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Sample records for high co2 content

  1. ABSORPTION OF CO2 IN HIGH ACRYLONITRILE CONTENT COPOLYMERS: DEPENDENCE ON ACRYLONITRILE CONTENT. (R829555)

    Science.gov (United States)

    In continuation of our goal to determine the ability of CO2 to plasticize acrylonitrile (AN) copolymers and facilitate melt processing at temperatures below the onset of thermal degradation, a systematic study has been performed to determine the influence of AN cont...

  2. One-Step Synthesis of Microporous Carbon Monoliths Derived from Biomass with High Nitrogen Doping Content for Highly Selective CO2 Capture.

    Science.gov (United States)

    Geng, Zhen; Xiao, Qiangfeng; Lv, Hong; Li, Bing; Wu, Haobin; Lu, Yunfeng; Zhang, Cunman

    2016-08-04

    The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrogen content. Synergetic effects of its high surface area, microporous structure and high nitrogen content, especially rich nitrogen-containing groups for effective CO2 capture (i.e., phenyl amine and pyridine-nitrogen) lead to superior CO2/N2 selectivity up to 82, which is the highest among known nanoporous carbons. In addition, the resulting nitrogen-doped active carbons can be easily regenerated under mild conditions. Considering the outstanding CO2 capture performance, low production cost, simple synthesis procedure and easy scalability, the resulting nitrogen-doped microporous carbon monoliths are promising candidates for selective capture of CO2 in industrial applications.

  3. N2 and CO2 Adsorption by Soils with High Kaolinite Content from San Juan Amecac, Puebla, México

    Directory of Open Access Journals (Sweden)

    Karla Quiroz-Estrada

    2016-07-01

    Full Text Available Carbon dioxide (CO2 is considered one of the most important greenhouse gases in the study of climate change. CO2 adsorption was studied using the gas chromatography technique, while the Freundlich and Langmuir adsorption models were employed for processing isotherm data in the temperature range of 473–573 K. The isosteric heat of adsorption was calculated from the Clausius–Clapeyron equation. Moreover, the thermodynamic properties ΔG, ΔU, and ΔS were evaluated from the adsorption isotherms of Langmuir using the Van’t Hoff Equation. The four soil samples were recollected from San Juan Amecac, Puebla, Mexico, and their morphologies were investigated through X-ray diffraction (XRD and N2 adsorption at 77 K. The SJA4 soil has a crystalline Kaolinite phase, which is one of its non-metallic raw materials, and N2 isotherms allowed for the determination of pore size distributions and specific surface areas of soil samples. The Barrett–Joyner–Halenda (BJH distribution of pore diameters was bimodal with peaks at 1.04 and 3.7 nm, respectively. CO2 adsorption showed that the SJA1 soil afforded a higher amount of adsorbed CO2 in the temperature range from 453 to 573 K followed by SJA4 and finally SJA2, classifying this process as exothermic physisorption.

  4. The Effect of Injection Timing on the Performance of Natural Gas with a High Carbon Dioxide (CO2 Content in a Direct Injection (DI Gas Engine

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    Wasiu Ayandotun B.

    2014-07-01

    Full Text Available This paper investigates the potential of utilizing raw natural gas from its reserves in Malaysia which are not harnessed because they are uneconomical due to the presence of large CO2 in it ranging from 25 to 89%. For this experimental work, the natural gas fields were simulated by adding CO2 at 10%, 20%, 30%, and 40% to pure natural gas, and tested in a single-cylinder spark-ignition direct injection (DI compressed natural gas (CNG engine. Various injection timings were used, the injection duration was maintained, the ignition timing was adjusted to obtain the maximum brake torque (MBT, and at wide open throttle (WOT. The tests were carried out at a constant engine speed to study the effect of injection timings on performance and emission of the engine. Experimental results show that generally, the presence of high carbon dioxide content in the natural gas reduces the heating value of the mixture when compared with pure natural gas but however could be enhanced with injection timing in the range of 120 and 180 particularly for 20% CO2 proportion in the mixture. There was a reduction in the NOX and CO emissions but an increase in the unburnt hydrocarbons (THC.

  5. Compact, High Accuracy CO2 Monitor Project

    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...

  6. Compact, High Accuracy CO2 Monitor Project

    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...

  7. Poly(ionic liquid)/Ionic Liquid Ion-Gels with High "Free" Ionic Liquid Content: Platform Membrane Materials for CO2/Light Gas Separations.

    Science.gov (United States)

    Cowan, Matthew G; Gin, Douglas L; Noble, Richard D

    2016-04-19

    The recycling or sequestration of carbon dioxide (CO2) from the waste gas of fossil-fuel power plants is widely acknowledged as one of the most realistic strategies for delaying or avoiding the severest environmental, economic, political, and social consequences that will result from global climate change and ocean acidification. For context, in 2013 coal and natural gas power plants accounted for roughly 31% of total U.S. CO2 emissions. Recycling or sequestering this CO2 would reduce U.S. emissions by ca. 1800 million metric tons-easily meeting the U.S.'s currently stated CO2 reduction targets of ca. 17% relative to 2005 levels by 2020. This situation is similar for many developed and developing nations, many of which officially target a 20% reduction relative to 1990 baseline levels by 2020. To make CO2 recycling or sequestration processes technologically and economically viable, the CO2 must first be separated from the rest of the waste gas mixture-which is comprised mostly of nitrogen gas and water (ca. 85%). Of the many potential separation technologies available, membrane technology is particularly attractive due to its low energy operating cost, low maintenance, smaller equipment footprint, and relatively facile retrofit integration with existing power plant designs. From a techno-economic standpoint, the separation of CO2 from flue gas requires membranes that can process extremely high amounts of CO2 over a short time period, a property defined as the membrane "permeance". In contrast, the membrane's CO2/N2 selectivity has only a minor effect on the overall cost of some separation processes once a threshold permeability selectivity of ca. 20 is reached. Given the above criteria, the critical properties when developing membrane materials for postcombustion CO2 separation are CO2 permeability (i.e., the rate of CO2 transport normalized to the material thickness), a reasonable CO2/N2 selectivity (≥20), and the ability to be processed into defect-free thin

  8. Utilization of high CO2 content formation gas for steam and electricity generation; Aprovechamiento del gas de formacion con alto contenido de CO2 para generacion de vapor y electricidad

    Energy Technology Data Exchange (ETDEWEB)

    Villagomez, Paul; Lamino, Marcelo; Jacome, Jose; Pastor, Santiago [EcuadorTLC, Quito (Ecuador). Grupo PETROBRAS

    2008-07-01

    Ecuador TLC SA, as part of the PETROBRAS Group, respecting its mission to act safe, cost-effectiveness, social and environmental responsibility, currently operates an oil production project in the Ecuatorian Amazon, known as Block 18. In Block 18, the process of gas burning is response for launch approximately 10 MMSCF of the gas associated with 77% CO2 in the environment. For this reason it was built a centralized power generation plants (PGE), of 17.38 MW, taking advantage of the gas with 77% CO2 from boilers to burn it, using it as a source of heat in a combined cycle steam turbines, generating electricity. This project is environmentally efficient with reduced emissions of CO2 and as reducing fuel costs to zero. The results of CO2 reduction is a corporate goal of PETROBRAS and this project will contribute to reducing CO2 emissions by approximately 400,000 Ton over the life of the project.

  9. THE HIGH GAIN CO2 LASER BY EFFECTIVE MIXING OF N2 AND CO2 GAS

    OpenAIRE

    Hara, H.; Fujisawa, A.

    1980-01-01

    A high-gain CO2 laser is described in which vibrationally excited N2 gas and cold CO2 gas are mixed effectively by means of the diffusion of CO2 gas into N2 gas. By using different types of mixing techniques, a maximum gain of 11 m-1 was obtained when CO2 gas was injected parallel to the expanding N2 gas flow. An output power of 4 W was obtained from an 1.2 cm active length. In addition, He gas addition to the N2 gas flow was found to decrease the small-signal gain with increasing He gas flow...

  10. Isolation of microorganisms from CO2 sequestration sites through enrichments under high pCO2

    Science.gov (United States)

    Peet, K. C.; Freedman, A. J.; Boreham, C.; Thompson, J. R.

    2012-12-01

    Carbon Capture and Storage (CCS) in geologic formations has the potential to reduce greenhouse gas emissions from fossil fuel processing and combustion. However, little is known about the effects that CO2 may have on biological activity in deep earth environments. To understand microorganisms associated with these environments, we have developed a simple high-pressure enrichment methodology to cultivate organisms capable of growth under supercritical CO2 (scCO2). Growth media targeting different subsurface functional metabolic groups is added to sterilized 316 stainless steel tubing sealed with quarter turn plug valves values and pressurized to 120-136 atm using a helium-padded CO2 tank, followed by incubation at 37 °C to achieve the scCO2 state. Repeated passages of crushed subsurface rock samples and growth media under supercritical CO2 headspaces are assessed for growth via microscopic enumeration. We have utilized this method to survey sandstone cores for microbes capable of growth under scCO2 from two different geologic sites targeted for carbon sequestration activities. Reproducible growth of microbial biomass under high pCO2 has been sustained from each site. Cell morphologies consist of primarily 1-2 μm rods and oval spores, with densities from 1E5-1E7 cells per ml of culture. We have purified and characterized a bacterial strain most closely related to Bacillus subterraneus (99% 16S rRNA identity) capable of growth under scCO2. Preliminary physiological characterization of this strain indicates it is a spore-forming facultative anaerobe able to grow in 0.5 to 50 ppt salinity. Genome sequencing and analysis currently in progress will help reveal genetic mechanisms of acclimation to high pCO2 conditions associated with geologic carbon sequestration.

  11. CO2-helium and CO2-neon mixtures at high pressures.

    Science.gov (United States)

    Mallick, B; Ninet, S; Le Marchand, G; Munsch, P; Datchi, F

    2013-01-28

    The properties of mixtures of carbon dioxide with helium or neon have been investigated as a function of CO(2) concentration and pressure up to 30 GPa at room temperature. The binary phase diagrams of these mixtures are determined over the full range of CO(2) concentrations using visual observations and Raman scattering measurements. Both diagrams are of eutectic type, with a fluid-fluid miscibility gap for CO(2) concentrations in the range [5, 75] mol. % for He and [8, 55] mol. % for Ne, and a complete separation between the two components in the solid phase. The absence of alloys or stoichiometric compounds for these two binary systems is consistent with the Hume-Rothery rules of hard sphere mixtures. The Raman spectra and x-ray diffraction patterns of solid CO(2) embedded in He or Ne for various initial concentrations have been measured up to 30 GPa and 12 GPa, respectively. The frequencies of the Raman modes and the volume of solid phase I are identical, within error bars, to those reported for 100% CO(2) samples, thus confirming the total immiscibility of CO(2) with He and Ne in the solid phase. These results demonstrate the possibility to perform high-pressure experiments on solid CO(2) under (quasi-)hydrostatic conditions using He or Ne as pressure transmitting medium.

  12. Novel porous carbon materials with ultrahigh nitrogen contents for selective CO 2 capture

    KAUST Repository

    Zhao, Yunfeng

    2012-01-01

    Nitrogen-doped carbon materials were prepared by a nanocasting route using tri-continuous mesoporous silica IBN-9 as a hard template. Rationally choosing carbon precursors and carefully controlling activation conditions result in an optimized material denoted as IBN9-NC1-A, which possesses a very high nitrogen doping concentration (∼13 wt%) and a large surface area of 890 m 2 g -1 arising from micropores (<1 nm). It exhibits an excellent performance for CO 2 adsorption over a wide range of CO 2 pressures. Specifically, its equilibrium CO 2 adsorption capacity at 25 °C reaches up to 4.50 mmol g -1 at 1 bar and 10.53 mmol g -1 at 8 bar. In particular, it shows a much higher CO 2 uptake at low pressure (e.g. 1.75 mmol g -1 at 25 °C and 0.2 bar) than any reported carbon-based materials, owing to its unprecedented nitrogen doping level. The high nitrogen contents also give rise to significantly enhanced CO 2/N 2 selectivities (up to 42), which combined with the high adsorption capacities, make these new carbon materials promising sorbents for selective CO 2 capture from power plant flue gas and other relevant applications. © 2012 The Royal Society of Chemistry.

  13. [Photosynthetic oxygen evolution and CO2 photoassimilation by cyanobacteria that form water-bloom spots in a sulfur spring with a high sulfide content].

    Science.gov (United States)

    Barskiĭ, E L; Nikitina, K A; Belogurova, N G; Gorskaia, N V; Gusev, M B

    1980-01-01

    Cyanobacteria belonging mainly to the genera Anabaena and Oscillatoria were isolated from water-bloom spots of a sulfur spring in Staraya Matsesta. Their suspensions evolved O2 at a rate of 6--8 nM/min per 1 mg of dry cell weight at an intensity of solar radiation being 60--75 mV/cm2 per 1 sec. The cells were also capable of CO2 photoassimilation in the presence of solfide at a rate of 10(-4) mg C per mg per hour. DCMU at a concentration of 10(-5) M completely inhibited O2 evolution and inhibited CO2 fixation by 80%. Oxygen assimilation in dark by the suspensions did not depend on the addition of cyanide and was caused apparently by nonenzymatic reduction of O2 with sulfide dissolved in the spring water. Oxygen assimilation by the suspensions in light in the presence of DCMU was by 20--30% greater than in dark. Therefore, the cells of cyanobacteria are characterized by photorespiration at the level of photosystem I. Presumably, sulfide at a concentration of 9 mM cannot significantly inhibit the photosynthetic processes in cyanobacteria producing water-bloom spots in the sulfur spring.

  14. High gain, multiatmosphere CO2 laser amplifier

    Science.gov (United States)

    Stuart, G. C.; Houtman, H.; Meyer, J.

    1987-02-01

    A novel TE discharge, 15-mm aperture, multiatmosphere, CO2 laser amplifier is described, with measured electrical characteristics and gain measurements on the 9.294-micron, 9R (16) line. The electrical circuit used in this amplifier is a realistic alternative to the Marx bank or conventional LC inversion circuit and, similarly, it would be useful for excitation of other gas lasers as well. This automatically preionized, double-sided, fourfold LC inversion circuit uses only one spark gap, and it is shown to provide small-signal gains of 5.7 percent/cm, at 120 J/l atm and 10 atm. The generalization to an n-stage device, which would be suitable for higher pressures, and larger apertures, is discussed.

  15. The Effect of CO2 Injection on Macroalgae Gelidium latifolium Biomass Growth Rate and Carbohydrate Content

    Directory of Open Access Journals (Sweden)

    Mujizat Kawaroe

    2016-06-01

    Full Text Available There are many species of macroalga grow in marine ecosystem and potentially as raw material for bioethanol resource. Bioethanol is a conversion result of carbohydrate, one of macroalgae biomass content. The exploration of macroalgae require information about  growth rate ability to determine availability in the nature. This research analyze growth rate and carbohydrate content of marine macroalga Gelidium latifolium on cultivation using varied injection of carbon dioxide and aeration. The treatments were control (K, 2000 cc CO2 injection and aeration (P1, 3000 cc CO2 injection and aeration (P2, 2000 cc CO2 injection without aeration (P3, and 3000 cc CO2 injection without aeration (P4. Samples weight were 3 gram in early cultivation on laboratorium scale for 42 days observation. The results showed that the daily growth rate Gelidium latifolium during the study ranged from 0.02-1.06%. The highest daily growth rate was 1.06±0.14% (P2. Carbohydrate yield was 18.23% in early cultivation then 19.40% (K and P2, 20.40% (P1, 16.87% (K3, and 16.40% (P4 after cultivation. The high of carbohydrates value may not guarantee the sustainable Gelidium latifolium biomass utilization as raw material for bioethanol production because of the low growth rate, thus it is necessary to modified and encourage cultivation method effectively. Keywords: CO2 injection, growth rate, carbohydrate, macroalgae, Gelidium latifolium

  16. Microbial growth under a high-pressure CO2 environment

    Science.gov (United States)

    Thompson, J. R.; Hernandez, H. H.

    2009-12-01

    Carbon capture and storage (CCS) of CO2 has the potential to significantly reduce the emission of greenhouse gasses associated with fossil fuel combustion. The largest potential for storing captured CO2 in the United Sates is in deep geologic saline formations. Currently, little is known about the effects of CO2 storage on biologically active microbial communities found in the deep earth biosphere. Therefore, to investigate how deep earth microbial communities will be affected by the storage of CO2, we have built a high-pressure microbial growth system in which microbial samples are subjected to a supercritical CO2 (scCO2) environment. Recently we have isolated a microbial consortium that is capable of growth and extracellular matrix production in nutrient media under a supercritical CO2 headspace. This consortium was cultivated from hydrocarbon residues associated with saline formation waters and includes members of the gram-positive Bacillus genus. The cultivation of actively growing cells in an environment containing scCO2 is unexpected based on previous experimental evidence of microbial sterilization attributed to the acidic, desiccating, and solvent-like properties of scCO2. Such microbial consortia have potential for development as (i) biofilm barriers for geological carbon-dioxide sequestration, and as (ii) agents of biocatalysis in environmentally-friendly supercritical (sc) CO2 solvent systems. The discovery that microbes can remain biologically active, and grow, in these environments opens new frontiers for the use of self-regenerating biological systems in engineering applications.

  17. Bubble formation and decrepitation control the CO2 content of olivine-hosted melt inclusions

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    Maclennan, J.

    2017-02-01

    The CO2 contents of olivine-hosted melt inclusions have previously been used to constrain the depth of magma chambers in basaltic systems. However, the vast majority of inclusions have CO2 contents which imply entrapment pressures that are significantly lower than those obtained from independent petrological barometers. Furthermore, a global database of melt inclusion compositions from low H2O settings, indicates that the distribution of saturation pressures varies surprisingly little between mid-ocean ridges, ocean islands, and continental rift zones. 95% of the inclusions in the database have saturation pressures of 200 MPa or less, indicating that melt inclusion CO2 does not generally provide an accurate estimate of magma chamber depths. A model of the P-V-T-X evolution of olivine-hosted melt inclusions was developed so that the properties of the inclusion system could be tracked as the hosts follow a model P-T path. The models indicate that the principal control on the saturation of CO2 in the inclusion and the formation of vapor bubbles is the effect of postentrapment crystallization on the major element composition of the inclusions and how this translates into variation in CO2 solubility. The pressure difference between external melt and the inclusion is likely to be sufficiently high to cause decrepitation of inclusions in most settings. Decrepitation can account for the apparent mismatch between CO2-based barometry and other petrological barometers, and can also account for the observed global distribution of saturation pressures. Only when substantial postentrapment crystallization occurs can reconstructed inclusion compositions provide an accurate estimate of magma chamber depth.

  18. Effects of explicit atmospheric convection at high CO2.

    Science.gov (United States)

    Arnold, Nathan P; Branson, Mark; Burt, Melissa A; Abbot, Dorian S; Kuang, Zhiming; Randall, David A; Tziperman, Eli

    2014-07-29

    The effect of clouds on climate remains the largest uncertainty in climate change predictions, due to the inability of global climate models (GCMs) to resolve essential small-scale cloud and convection processes. We compare preindustrial and quadrupled CO2 simulations between a conventional GCM in which convection is parameterized and a "superparameterized" model in which convection is explicitly simulated with a cloud-permitting model in each grid cell. We find that the global responses of the two models to increased CO2 are broadly similar: both simulate ice-free Arctic summers, wintertime Arctic convection, and enhanced Madden-Julian oscillation (MJO) activity. Superparameterization produces significant differences at both CO2 levels, including greater Arctic cloud cover, further reduced sea ice area at high CO2, and a stronger increase with CO2 of the MJO.

  19. 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.

  20. Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution

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    Yingying Jing

    2014-11-01

    Full Text Available Satellite measurements of the spatiotemporal distributions of atmospheric CO2 concentrations are a key component for better understanding global carbon cycle characteristics. Currently, several satellite instruments such as the Greenhouse gases Observing SATellite (GOSAT, SCanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY, and Orbiting Carbon Observatory-2 can be used to measure CO2 column-averaged dry air mole fractions. However, because of cloud effects, a single satellite can only provide limited CO2 data, resulting in significant uncertainty in the characterization of the spatiotemporal distribution of atmospheric CO2 concentrations. In this study, a new physical data fusion technique is proposed to combine the GOSAT and SCIAMACHY measurements. On the basis of the fused dataset, a gap-filling method developed by modeling the spatial correlation structures of CO2 concentrations is presented with the goal of generating global land CO2 distribution maps with high spatiotemporal resolution. The results show that, compared with the single satellite dataset (i.e., GOSAT or SCIAMACHY, the global spatial coverage of the fused dataset is significantly increased (reaching up to approximately 20%, and the temporal resolution is improved by two or three times. The spatial coverage and monthly variations of the generated global CO2 distributions are also investigated. Comparisons with ground-based Total Carbon Column Observing Network (TCCON measurements reveal that CO2 distributions based on the gap-filling method show good agreement with TCCON records despite some biases. These results demonstrate that the fused dataset as well as the gap-filling method are rather effective to generate global CO2 distribution with high accuracies and high spatiotemporal resolution.

  1. High-Density Nanosharp Microstructures Enable Efficient CO2 Electroreduction.

    Science.gov (United States)

    Saberi Safaei, Tina; Mepham, Adam; Zheng, Xueli; Pang, Yuanjie; Dinh, Cao-Thang; Liu, Min; Sinton, David; Kelley, Shana O; Sargent, Edward H

    2016-11-09

    Conversion of CO2 to CO powered by renewable electricity not only reduces CO2 pollution but also is a means to store renewable energy via chemical production of fuels from CO. However, the kinetics of this reaction are slow due its large energetic barrier. We have recently reported CO2 reduction that is considerably enhanced via local electric field concentration at the tips of sharp gold nanostructures. The high local electric field enhances CO2 concentration at the catalytic active sites, lowering the activation barrier. Here we engineer the nucleation and growth of next-generation Au nanostructures. The electroplating overpotential was manipulated to generate an appreciably increased density of honed nanoneedles. Using this approach, we report the first application of sequential electrodeposition to increase the density of sharp tips in CO2 electroreduction. Selective regions of the primary nanoneedles are passivated using a thiol SAM (self-assembled monolayer), and then growth is concentrated atop the uncovered high-energy planes, providing new nucleation sites that ultimately lead to an increase in the density of the nanosharp structures. The two-step process leads to a new record in CO2 to CO reduction, with a geometric current density of 38 mA/cm2 at -0.4 V (vs reversible hydrogen electrode), and a 15-fold improvement over the best prior reports of electrochemical surface area (ECSA) normalized current density.

  2. Enhanced lipid accumulation of photoautotrophic microalgae by high-dose CO2 mimics a heterotrophic characterization.

    Science.gov (United States)

    Sun, Zhilan; Dou, Xiao; Wu, Jun; He, Bing; Wang, Yuancong; Chen, Yi-Feng

    2016-01-01

    Microalgae possess higher photosynthetic efficiency and accumulate more neutral lipids when supplied with high-dose CO2. However, the nature of lipid accumulation under conditions of elevated CO2 has not been fully elucidated so far. We now revealed that the enhanced lipid accumulation of Chlorella in high-dose CO2 was as efficient as under heterotrophic conditions and this may be attributed to the driving of enlarged carbon source. Both photoautotrophic and heterotrophic cultures were established by using Chlorella sorokiniana CS-1. A series of changes in the carbon fixation, lipid accumulation, energy conversion, and carbon-lipid conversion under high-dose CO2 (1-10%) treatment were characterized subsequently. The daily carbon fixation rate of C. sorokiniana LS-2 in 10% CO2 aeration was significantly increased compared with air CO2. Correspondingly, double oil content (28%) was observed in 10% CO2 aeration, close to 32.3% produced under heterotrophic conditions. In addition, with 10% CO2 aeration, the overall energy yield (Ψ) in Chlorella reached 12.4 from 7.3% (with air aeration) because of the enhanced daily carbon fixation rates. This treatment also improved the energetic lipid yield (Ylipid/Es) with 4.7-fold, tending to the heterotrophic parameters. More significantly, 2.2 times of carbon-lipid conversion efficiency (ηClipid/Ctotal, 42.4%) was observed in 10% CO2 aeration, towards to 53.7% in heterotrophic cultures, suggesting that more fixed carbon might flow into lipid synthesis under both 10% CO2 aeration and heterotrophic conditions. Taken together, all our evidence showed that 10% CO2 may push photoautotrophic Chlorella to display heterotrophic-like efficiency at least in lipid production. It might bring us an efficient model of lipid production based on microalgal cells with high-dose CO2, which is essential to sustain biodiesel production at large scales.

  3. Leaf Photosynthesis and Respiration of High CO2-Grown Tobacco Plants Selected for Survival under CO2 Compensation Point Conditions 1

    Science.gov (United States)

    Delgado, Esteban; Azcón-Bieto, Joaquim; Aranda, Xavier; Palazón, Javier; Medrano, Hipólito

    1992-01-01

    Four self-pollinated, doubled-haploid tobacco, (Nicotiana tabacum L.) lines (SP422, SP432, SP435, and SP451), selected as haploids by survival in a low CO2 atmosphere, and the parental cv Wisconsin-38 were grown from seed in a growth room kept at high CO2 levels (600-700 parts per million). The selected plants were much larger (especially SP422, SP432, and SP451) than Wisconsin-38 nine weeks after planting. The specific leaf dry weight and the carbon (but not nitrogen and sulfur) content per unit area were also higher in the selected plants. However, the chlorophyll, carotenoid, and alkaloid contents and the chlorophyll a/b ratio varied little. The net CO2 assimilation rate per unit area measured in the growth room at high CO2 was not higher in the selected plants. The CO2 assimilation rate versus intercellular CO2 curve and the CO2 compensation point showed no substantial differences among the different lines, even though these plants were selected for survival under CO2 compensation point conditions. Adult leaf respiration rates were similar when expressed per unit area but were lower in the selected lines when expressed per unit dry weight. Leaf respiration rates were negatively correlated with specific leaf dry weight and with the carbon content per unit area and were positively correlated with nitrogen and sulfur content of the dry matter. The alternative pathway was not involved in respiration in the dark in these leaves. The better carbon economy of tobacco lines selected for low CO2 survival was not apparently related to an improvement of photosynthesis rate but could be related, at least partially, to a significantly reduced respiration (mainly cytochrome pathway) rate per unit carbon. ImagesFigure 1 PMID:16668769

  4. Lipid content and fatty acid composition of Porosira glacialis and Attheya longicornis in response to carbon dioxide (CO2 aeration.

    Directory of Open Access Journals (Sweden)

    E Y Artamonova

    Full Text Available In the current study two novel psychrophilic diatoms Porosira glacialis and Attheya longicornis were tested for suitability to CO2 mitigation coupled with production of the physiologically requisite omega- 3 fatty acids. This study is in line with the worldwide conducted research aimed at applying biorefinery concept to heavy polluting industries. Since the production of algal high value compounds, i.e. essential fatty acids, relies on utilization of residual CO2 emissions coming from industry, the costs of such production maybe substantially reduced. Besides, the ecological benefits of the biorefinery concept being implemented are obvious, since CO2 is one of the major greenhouse gases. The current research has shown that one of the tested microalgal species, the diatom P. glacialis showed good tolerance to high (20-25% levels of CO2 and maintained growth rates comparable to controls. The total lipid content in the CO2 aerated culture increased from 8.91 to 10.57% in cell dry mass. Additionally, the content of docosahexaenoic acid (DHA increased from 3.90 to 5.75%, while the concentration of eicosapentaenoic acid (EPA decreased from 26.59 to 23.66%. In contrast, A. longicornis did not demonstrate any significant increase in total lipid content. Besides, its growth was hampered by high levels of CO2 aeration.

  5. 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

  6. Effects of CO2 on stomatal conductance: do stomata open at very high CO2 concentrations?

    Science.gov (United States)

    Wheeler, R. M.; Mackowiak, C. L.; Yorio, N. C.; Sager, J. C.

    1999-01-01

    Potato and wheat plants were grown for 50 d at 400, 1000 and 10000 micromoles mol-1 carbon dioxide (CO2). and sweetpotato and soybean were grown at 1000 micromoles mol-1 CO2 in controlled environment chambers to study stomatal conductance and plant water use. Lighting was provided with fluorescent lamps as a 12 h photoperiod with 300 micromoles m-2 s-1 PAR. Mid-day stomatal conductances for potato were greatest at 400 and 10000 micromoles mol-1 and least at 1000 micromoles mol-1 CO2. Mid-day conductances for wheat were greatest at 400 micromoles mol-1 and least at 1000 and 10000 micromoles mol-1 CO2. Mid-dark period conductances for potato were significantly greater at 10000 micromoles mol-1 than at 400 or 1000 micromoles mol-1, whereas dark conductance for wheat was similar in all CO2 treatments. Temporarily changing the CO2 concentration from the native 1000 micromoles mol-1 to 400 micromoles mol-1 increased mid-day conductance for all species, while temporarily changing from 1000 to 10000 micromoles mol-1 also increased conductance for potato and sweetpotato. Temporarily changing the dark period CO2 from 1000 to 10000 micromoles mol-1 increased conductance for potato, soybean and sweetpotato. In all cases, the stomatal responses were reversible, i.e. conductances returned to original rates following temporary changes in CO2 concentration. Canopy water use for potato was greatest at 10000, intermediate at 400, and least at 1000 micromoles mol-1 CO2, whereas canopy water use for wheat was greatest at 400 and similar at 1000 and 10000 micromoles mol-1 CO2. Elevated CO2 treatments (i.e. 1000 and 10000 micromoles mol-1) resulted in increased plant biomass for both wheat and potato relative to 400 micromoles mol-1, and no injurious effects were apparent from the 10000 micromoles mol-1 treatment. Results indicate that super-elevated CO2 (i.e. 10000 micromoles mol-1) can increase stomatal conductance in some species, particularly during the dark period, resulting in

  7. Influence of shale-total organic content on CO2 geo-storage potential

    Science.gov (United States)

    Arif, Muhammad; Lebedev, Maxim; Barifcani, Ahmed; Iglauer, Stefan

    2017-09-01

    Shale CO2 wettability is a key factor which determines the structural trapping capacity of a caprock. However, the influence of shale-total organic content (TOC) on wettability (and thus on storage potential) has not been evaluated despite the fact that naturally occurring shale formations can vary dramatically in TOC, and that even minute TOC strongly affects storage capacities and containment security. Thus, there is a serious lack of understanding in terms of how shale, with varying organic content, performs in a CO2 geo-storage context. We demonstrate here that CO2-wettability scales with shale-TOC at storage conditions, and we propose that if TOC is low, shale is suitable as a caprock in conventional structural trapping scenarios, while if TOC is ultrahigh to medium, the shale itself is suitable as a storage medium (via adsorption trapping after CO2 injection through fractured horizontal wells).

  8. 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.

  9. 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.

  10. 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.

  11. Study of Pyridine-Mediated Electrochemical Reduction of CO2 to Methanol at High CO2 Pressure.

    Science.gov (United States)

    Rybchenko, Sergey I; Touhami, Dalila; Wadhawan, Jay D; Haywood, Stephanie K

    2016-07-07

    The recently proposed highly efficient route of pyridine-catalyzed CO2 reduction to methanol was explored on platinum electrodes at high CO2 pressure. At 55 bar (5.5 MPa) of CO2 , the bulk electrolysis in both potentiostatic and galvanostatic regimes resulted in methanol production with Faradaic yields of up to 10 % for the first 5-10 C cm(-2) of charge passed. For longer electrolysis, the methanol concentration failed to increase proportionally and was limited to sub-ppm levels irrespective of biasing conditions and pyridine concentration. This limitation cannot be removed by electrode reactivation and/or pre-electrolysis and appears to be an inherent feature of the reduction process. In agreement with bulk electrolysis findings, the CV analysis supported by simulation indicated that hydrogen evolution is still the dominant electrode reaction in pyridine-containing electrolyte solution, even with an excess CO2 concentration in the solution. No prominent contribution from either a direct or coupled CO2 reduction was found. The results obtained suggest that the reduction of CO2 to methanol is a transient process that is largely decoupled from the electrode charge transfer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. 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.

  13. Effect of CO_2 levels on nutrient content of lettuce and radish

    Science.gov (United States)

    McKeehen, J. D.; Smart, D. J.; Mackowiak, C. L.; Wheeler, R. M.; Nielsen, S. S.

    Atmospheric carbon-dioxide enrichment is known to affect the yield of lettuce and radish grown in controlled environments, but little is known about CO_2 enrichment effects on the chemical composition of lettuce and radish. These crops are useful model systems for a Controlled Ecological Life-Support System (CELSS), largely because of their relatively short production cycles. Lettuce (Lactuca sativa L.) cultivar `Waldmann's Green' and radish (Raphanus sativus L.) cultivar `Giant White Globe' were grown both in the field and in controlled environments, where hydroponic nutrient solution, light, and temperature were regulated, and where CO_2 levels were controlled at 400, 1000, 5000, or 10,000 ppm. Plants were harvested at maturity, dried, and analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate N, free sugars, starch, total dietary fiber, and minerals. Total N, protein N, nonprotein N (NPN), and nitrate N generally increased for radish roots and lettuce leaves when grown under growth chamber conditions compared to field conditions. The nitrate-N level of lettuce leaves, as a percentage of total NPN, decreased with increasing levels of CO_2 enrichment. The ash content of radish roots and of radish and lettuce leaves decreased with increasing levels of CO_2 enrichment. The levels of certain minerals differed between field- and chamber-grown materials, including changes in the calcium (Ca) and phosphorus (P) contents of radish roots and lettuce leaves, resulting in reduced Ca/P ratio for chamber-grown materials. The free-sugar contents were similar between the field and chamber-grown lettuce leaves, but total dietary fiber content was much higher in the field-grown plant material. The starch content of growth-chamber lettuce increased with CO_2 level.

  14. Effect of CO2 levels on nutrient content of lettuce and radish

    Science.gov (United States)

    McKeehen, J. D.; Smart, D. J.; Mackowiak, C. L.; Wheeler, R. M.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1996-01-01

    Atmospheric carbon-dioxide enrichment is known to affect the yield of lettuce and radish grown in controlled environments, but little is known about CO2 enrichment effects on the chemical composition of lettuce and radish. These crops are useful model systems for a Controlled Ecological Life-Support System (CELSS), largely because of their relatively short production cycles. Lettuce (Lactuca sativa L.) cultivar 'Waldmann's Green' and radish (Raphanus sativus L.) cultivar 'Giant White Globe' were grown both in the field and in controlled environments, where hydroponic nutrient solution, light, and temperature were regulated, and where CO2 levels were controlled at 400, 1000, 5000, or 10,000 ppm. Plants were harvested at maturity, dried, and analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate N, free sugars, starch, total dietary fiber, and minerals. Total N, protein N, nonprotein N (NPN), and nitrate N generally increased for radish roots and lettuce leaves when grown under growth chamber conditions compared to field conditions. The nitrate-N level of lettuce leaves, as a percentage of total NPN, decreased with increasing levels of CO2 enrichment. The ash content of radish roots and of radish and lettuce leaves decreased with increasing levels of CO2 enrichment. The levels of certain minerals differed between field- and chamber-grown materials, including changes in the calcium (Ca) and phosphorus (P) contents of radish and lettuce leaves, resulting in reduced Ca/P ratio for chamber-grown materials. The free-sugar contents were similar between the field and chamber-grown lettuce leaves, but total dietary fiber content was much higher in the field-grown plant material. The starch content of growth-chamber lettuce increased with CO2 level.

  15. Sudden and unpredictable below-surface ablation pattern changes by CO2 laser beams: a qualitative description of five macroscopic cases observed in PMMA with high probability to occur during surgery in low-water-content tissues.

    Science.gov (United States)

    Canestri, Franco

    2002-12-01

    This paper describes five cases of macroscopic irregular CO(2) laser-beam ablation patterns that can generate below-surface complications during surgery. These five cases are related to curved reflected beams, curved craters generation with abnormal superficial thermal damage, and craters that show irregular wall contours. Although these alterations have been observed during irradiation in PMMA samples (polymethilmethacrylate), it is possible that similar unpredictable changes also happen in low-water-content, hard and uniform biological tissues such as compact bone, enamel, and dentin. This fact can predict severe impacts on the quality of the final surgical outcome, especially there where precision surgery techniques are required. A qualitative description about the possible causes of these effects and how to avoid them during surgery have been suggested too. In the past decades, daily surgery and research studies have provided useful information about the interaction between medical CO(2) laser beams and animal, human, and other biological tissues. Several mathematical models describe with acceptable accuracy all the ablative properties of the 10.6 microm laser beam. Very few studies describe the presence and address the consequences of the ablative aberrations, which can frequently and randomly happen during laser surgery. The probability that these changes happen in below-surface, therefore invisible, parts of the biologic media under treatment makes the whole matter crucial, even in cases of traditional surgery. Where gross mass removals are considered, the presence of unpredictable and sudden deviations from the expected traditional cone-shaped patterns raise several questions about safety. The continuous need for properly engineered medical laser-beam devices, online laser-beam monitoring, and real-time control becomes mandatory in modern surgery. The equipment used in this study was provided by the National Cancer Institute of Milan, Milan, Italy, and by

  16. A 10 cm aperture, high quality TEA CO2 laser

    NARCIS (Netherlands)

    Ernst, G.J.

    1982-01-01

    Experiments have been performed on a corona preionization type 10 cm aperture TEA CO2 laser. For a CO2:N2:He=1: 1: 7: mixture an output energy of 34 joule per liter and for a 1 : 1 : 10 mixture 40 joule per liter could be obtained. The overall efficiency is about 18%. The time behaviour of the

  17. High-Performance Polymers for Membrane CO2/N2Separation.

    Science.gov (United States)

    Liu, Junyi; Hou, Xianda; Park, Ho Bum; Lin, Haiqing

    2016-11-02

    This Concept examines strategies to design advanced polymers with high CO 2 permeability and high CO 2 /N 2 selectivity, which are the key to the success of membrane technology for CO 2 capture from fossil fuel-fired power plants. Specifically, polymers with enhanced CO 2 solubility and thus CO 2 /N 2 selectivity are designed by incorporating CO 2 -philic groups in polymers such as poly(ethylene oxide)-containing polymers and poly(ionic liquids); polymers with enhanced CO 2 diffusivity and thus CO 2 permeability are designed with contorted rigid polymer chains to obtain high free volume, such as polymers with intrinsic microporosity and thermally rearranged polymers. The underlying rationales for materials design are discussed and polymers with promising CO 2 /N 2 separation properties for CO 2 capture from flue gas are highlighted. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Development of a mobile and high-precision atmospheric CO2 monitoring station

    Science.gov (United States)

    Molnár, M.; Haszpra, L.; Major, I.; Svingor, É.; Veres, M.

    2009-04-01

    Nowadays one of the most burning questions for the science is the rate and the reasons of the recent climate change. Greenhouse gases (GHG), mainly CO2 and CH4 in the atmosphere could affect the climate of our planet. However, the relation between the amount of atmospheric GHG and the climate is complex, full with interactions and feedbacks partly poorly known even by now. The only way to understand the processes, to trace the changes, to develop and validate mathematical models for forecasts is the extensive, high precision, continuous monitoring of the atmosphere. Fossil fuel CO2 emissions are a major component of the European carbon budget. Separation of the fossil fuel signal from the natural biogenic one in the atmosphere is, therefore, a crucial task for quantifying exchange flux of the continental biosphere through atmospheric observations and inverse modelling. An independent method to estimate trace gas emissions is the top-down approach, using atmospheric CO2 concentration measurements combined with simultaneous radiocarbon (14C) observations. As adding fossil fuel CO2 to the atmosphere, therefore, leads not only to an increase in the CO2 content of the atmosphere but also to a decrease in the 14C/12C ratio in atmospheric CO2. The ATOMKI has more than two decade long experience in atmospheric 14CO2 monitoring. As a part of an ongoing research project being carried out in Hungary to investigate the amount and temporal and spatial variations of fossil fuel CO2 in the near surface atmosphere we developed a mobile and high-precision atmospheric CO2 monitoring station. We describe the layout and the operation of the measuring system which is designed for the continuous, unattended monitoring of CO2 mixing ratio in the near surface atmosphere based on an Ultramat 6F (Siemens) infrared gas analyser. In the station one atmospheric 14CO2 sampling unit is also installed which is developed and widely used since more than one decade by ATOMKI. Mixing ratio of CO2 is

  19. Soil water content drives spatiotemporal patterns of CO2 and N2O emissions from a Mediterranean riparian forest soil

    Science.gov (United States)

    Poblador, Sílvia; Lupon, Anna; Sabaté, Santiago; Sabater, Francesc

    2017-09-01

    Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gas (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Riparian soils emitted larger amounts of CO2 (1.2-10 g C m-2 d-1) than N2O (0.001-0.2 mg N m-2 d-1) to the atmosphere attributed to high respiration and low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil water content across the riparian zone. Deep groundwater tables fueled large soil CO2 effluxes near the hillslope, while N2O emissions were higher in the wet zones adjacent to the stream channel. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil water content, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, our results highlight the role of water availability on riparian soil biogeochemistry and GHG emissions and suggest that climate change alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to regional and global biogeochemical cycles.

  20. Competitive sorption of CO2 and CH4 on coals as a function of maturity and moisture content

    Science.gov (United States)

    Merkel, Alexej; Gensterblum, Yves; Kroos, Bernhard; Littke, Ralf

    2013-04-01

    The competitive sorption of CH4 and CO2 from a two-component gas mixture on coals of different rank and moisture content has been studied at pressures up to 10 MPa. The aim of this study was to assess, the maximum sorption capacity as well as the selectivity of dry and moisturised coals of different rank with respect to sorption of CH4and CO2. The research addresses possible implications on Enhanced Coal Bed Methane (ECBM) recovery projects, where CO2is to be injected into coal seams to increase CH4production rates. The measurements were conducted using a manometric setup with continuous pressure and temperature recording and periodic analysis of gas compositions in the reference cell and the measuring cell throughout the duration of the experiment. Isotherms were determined with a gas mixture containing 70-80% CH4. Three isotherms were measured at three different moisture states for each of the three coal samples of different rank. A significant decrease of total excess sorption capacity was observed with increasing moisture content from the dry sample to the sample moisturised at 53% relative humidity (RH). The initial reduction of sorption capacity decreases with rank. Only a small further decrease occurred from 53% to the 97% RH moisturised coals. The effect of moisture on sorption capacity and selectivity is highly rank-dependent. In all cases the results show a preferential sorption of CO2from a binary CH4/CO2gas mixture at all three moisture states. Sorption capacity increases with rank for all but the dry state and in all cases the sample with the highest maturity shows the highest sorption capacity by far. Selectivity for CO2 decreases with increasing rank of the coal. The results of this study support that from the thermodynamic point of view coals have a tendency to selectively take up CO2under the conditions of ECBM recovery. The selectivity coefficients are important parameters for ECBM modelling and the design of production strategies.

  1. Simultaneous in situ CO2 soil flux and isotopic analysis in a high CO2 flux environment at Mammoth Mountain, CA

    Science.gov (United States)

    Bogue, R. R.; Oze, C.; Horton, T. W.; Defliese, W.

    2016-12-01

    Areas proximal to Mammoth Mountain, CA, have been emitting anomalously high CO2 for nearly three decades. High CO2 flux rates in these areas have resulted in tree kills and are potentially attributed to a large shallow CO2 reservoir fed by the breakdown of metasedimentary rocks and/or degassing from a mid-crustal magma body. Previous studies have focused largely on providing estimates of total CO2 efflux and the origin of CO2 release in the area. However, the nature and complexity of the interface between high CO2 flux and adjacent ecosystem have not been explored. Here we assess the spatial and temporal transition of the high CO2 flux zone and tree kill area into the adjacent forest ecosystem. In June and July 2016 extensive in situ diffuse soil CO2 flux and 13CO2 isotope measurements were conducted with a coupled West Systems/LICOR and Picarro. Additionally, gas samples were collected for Δ47 clumped isotope analyses. Compared to previous studies, areas of high CO2 flux have progressed northeast into a forest ecosystem, with some of the highest flux areas less than 20 meters from live trees. 13CO2 values primarily mirror areas of high CO2 flux with 13CO2 magmatic signatures; however, magmatic 13CO2 values are present in low CO2 flux and heavily forested areas. Δ47 values are depleted relative to equilibrium at ambient air and soil temperatures, indicating a high-temperature source. Young trees were also observed growing in areas that were part of the initial tree kill, providing tangible evidence of the impact of the movement of the high CO2 flux areas.

  2. Ocean Warming and CO2-Induced Acidification Impact the Lipid Content of a Marine Predatory Gastropod

    Directory of Open Access Journals (Sweden)

    Roselyn Valles-Regino

    2015-09-01

    Full Text Available Ocean warming and acidification are current global environmental challenges impacting aquatic organisms. A shift in conditions outside the optimal environmental range for marine species is likely to generate stress that could impact metabolic activity, with consequences for the biosynthesis of marine lipids. The aim of this study was to investigate differences in the lipid content of Dicathais orbita exposed to current and predicted future climate change scenarios. The whelks were exposed to a combination of temperature and CO2-induced acidification treatments in controlled flowthrough seawater mesocosms for 35 days. Under current conditions, D. orbita foot tissue has an average of 6 mg lipid/g tissue, but at predicted future ocean temperatures, the total lipid content dropped significantly, to almost half. The fatty acid composition is dominated by polyunsaturated fatty acids (PUFA 52% with an n-3:6 fatty acid ratio of almost 2, which remains unchanged under future ocean conditions. However, we detected an interactive effect of temperature and pCO2 on the % PUFAs and n-3 and n-6 fatty acids were significantly reduced by elevated water temperature, while both the saturated and monounsaturated fatty acids were significantly reduced under increased pCO2 acidifying conditions. The present study indicates the potential for relatively small predicted changes in ocean conditions to reduce lipid reserves and alter the fatty acid composition of a predatory marine mollusc. This has potential implications for the growth and survivorship of whelks under future conditions, but only minimal implications for human consumption of D. orbita as nutritional seafood are predicted.

  3. 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.

  4. Interactions between the effects of atmospheric CO2 content and P nutrition on photosynthesis in white lupin (Lupinus albus L.).

    Science.gov (United States)

    Campbell, Catherine D; Sage, Rowan E

    2006-05-01

    Phosphorus (P) is a major factor limiting the response of carbon acquisition of plants and ecosystems to increasing atmospheric CO2 content. An important consideration, however, is the effect of P deficiency at the low atmospheric CO2 content common in recent geological history, because plants adapted to these conditions may also be limited in their ability to respond to further increases in CO2 content. To ascertain the effects of low P on various components of photosynthesis, white lupin (Lupinus albus L.) was grown hydroponically at 200, 400 and 750 micromol mol(-1) CO2, under sufficient and deficient P supply (250 and 0.69 microM P, respectively). Increasing growth CO2 content increased photosynthesis only under sufficient growth P. Ribulose 1,5-biphosphate carboxylase/oxygenase (Rubisco) content and activation state were not reduced to the same degree as the net CO2 assimilation rate (A), and the in vivo rate of electron transport was sufficient to support photosynthesis in all cases. The rate of triose phosphate use did not appear limiting either, because all the treatments continued to respond positively to a drop in oxygen levels. We conclude that, at ambient and elevated CO2 content, photosynthesis in low-P plants appears limited by the rate of ribulose biphosphate (RuBP) regeneration, probably through inhibition of the Calvin cycle. This failure of P-deficient plants to respond to rising CO2 content above 200 micromol mol(-1) indicates that P status already imposes a widespread restriction in plant responses to increases in CO2 content from the pre-industrial level to current values.

  5. Non-photosynthetic enhancement of growth by high CO2 level in the nitrophilic seaweed Ulva rigida C. Agardh (Chlorophyta).

    Science.gov (United States)

    Gordillo, F J; Niell, F X; Figueroa, F L

    2001-05-01

    The effects of increased CO2 levels (10,000 microl l(-1)) in cultures of the green nitrophilic macroalga Ulva rigida C. Agardh were tested under conditions of N saturation and N limitation, using nitrate as the only N source. Enrichment with CO2 enhanced growth, while net photosynthesis, gross photosynthesis, dark respiration rates and soluble protein content decreased. The internal C pool remained constant at high CO2, while the assimilated C that was released to the external medium was less than half the values obtained under ambient CO2 levels. This higher retention of C provided the source for extra biomass production under N saturation. In N-sufficient thalli, nitrate-uptake rate and the activity of nitrate reductase (EC 1.6.6.1) increased under high CO2 levels. This did not affect the N content or the internal C:N balance, implying that the extra N-assimilation capacity led to the production of new biomass in proportion to C. Growth enhancement by increased level of CO2 was entirely dependent on the enhancement effect of CO2 on N-assimilation rates. The increase in nitrate reductase activity at high CO2 was not related to soluble carbohydrates or internal C. This indicates that the regulation of N assimilation by CO2 in U. rigida might involve a different pathway from that proposed for higher plants. The role of organic C release as an effective regulatory mechanism maintaining the internal C:N balance in response to different CO2 levels is discussed.

  6. Fatty acid production from a highly CO2 tolerant alga, Chlorocuccum littorale, in the presence of inorganic carbon and nitrate.

    Science.gov (United States)

    Ota, Masaki; Kato, Yoshitaka; Watanabe, Hiromoto; Watanabe, Masaru; Sato, Yoshiyuki; Smith, Richard L; Inomata, Hiroshi

    2009-11-01

    Photoautotrophic fatty acid production of a highly CO(2)-tolerant green alga Chlorococcum littorale was investigated in the presence of inorganic carbon and nitrate at 295 K and a light intensity of 170 micromol-photon m(-2) s(-1). CO(2) concentration in the bubbling gas was adjusted by mixing pure gas components of CO(2) and N(2) to avoid photorespiration and beta-oxidation of fatty acids under O(2) atmosphere conditions. Fatty acid content was almost constant for the CO(2) concentrations ranging from 5% to 50% under nitrate-rich conditions corresponding to the logarithmic growth phase. After nitrate depletion, the content drastically increased with a decrease in CO(2) concentration. HCO(3)(-)/CO(2) ratio in the culture media was found to be a controlling factor for fatty acid production after the nitrate limitation phase. For a CO(2) concentration of 5%, the fatty acid content was ca. 34 wt.% at maximum, which is comparable with other land plant seed oils.

  7. A new frontier in CO2 flux measurements using a highly portable DIAL laser system

    Science.gov (United States)

    Queiβer, Manuel; Granieri, Domenico; Burton, Mike

    2016-01-01

    Volcanic CO2 emissions play a key role in the geological carbon cycle, and monitoring of volcanic CO2 fluxes helps to forecast eruptions. The quantification of CO2 fluxes is challenging due to rapid dilution of magmatic CO2 in CO2-rich ambient air and the diffuse nature of many emissions, leading to large uncertainties in the global magmatic CO2 flux inventory. Here, we report measurements using a new DIAL laser remote sensing system for volcanic CO2 (CO2DIAL). Two sites in the volcanic zone of Campi Flegrei (Italy) were scanned, yielding CO2 path-amount profiles used to compute fluxes. Our results reveal a relatively high CO2 flux from Campi Flegrei, consistent with an increasing trend. Unlike previous methods, the CO2DIAL is able to measure integrated CO2 path-amounts at distances up to 2000 m using virtually any solid surface as a reflector, whilst also being highly portable. This opens a new frontier in quantification of geological and anthropogenic CO2 fluxes. PMID:27652775

  8. 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

  9. 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

  10. 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

    2017-10-25

    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 -SO2 functionalized organic linker (H2SDB = 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 CO2 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 CH4 (17 cm(3) g(-1) at 273 K and 13.6 cm(3) g(-1) at 295 K) and N2 (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 CO2 from flue gas as well as a landfill gas mixture. Based on the ideal adsorbed solution theory (IAST), a CO2/N2 selectivity of 435.5 and a CO2/CH4 selectivity of 151.6 have been realized at 273 K/100 kPa. The values at 295 K are 147.8 for CO2/N2 and 23.8 for CO2/CH4 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 CO2 loading capacity of 2.04 mmol g(-1).

  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 CO2 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 CO2 capture and storage process is accomplished in an emulsion-templated polymer foam, in which CO2 is breathed-in under dark and breathed-out under light illumination. Such a process is likely to become a relay of natural CO2 capture by plants that on the contrary breathe out CO2 at night. Recyclable CO2 capture at room temperature and release under light irradiation guarantee its convenient and cost-effective regeneration in industry. Furthermore, CO2 mixed with CH4 is successfully separated through this reversible breathing in and out system, which offers great promise for CO2 enrichment and practical methane purification.

  12. High-CO2 tolerance in microalgae: possible mechanisms and implications for biotechnology and bioremediation.

    Science.gov (United States)

    Solovchenko, Alexei; Khozin-Goldberg, Inna

    2013-11-01

    Recent developments in the field of microalgal biotechnology, including CO2 biomitigation and the discovery of new species of microalgae that are tolerant to extremely high CO2 levels (40-100 vol%), have renewed interest in the physiological effects and mechanisms of high-CO2 tolerance in photoautotrophs. Photosynthetic apparatus state transitions that increase ATP generation, upregulation of H(+)-ATPases pumping protons out of the cell, rapid shutdown of CO2-concentrating mechanisms, and adjustment of membranes' fatty acid composition are currently believed to be the key mechanisms governing cellular pH homeostasis and hence microalgae's tolerance to high CO2 levels, which is especially characteristic of extremophile and symbiotic species. The mechanisms governing acclimation to high CO2 comprise the subject of this review and are discussed in view of the use of CO2 enrichment to increase the productivity of microalgal cultures, as well as the practice of carbon capture from flue gases.

  13. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.).

    Science.gov (United States)

    La, Gui-xiao; Fang, Ping; Teng, Yi-bo; Li, Ya-juan; Lin, Xian-yong

    2009-06-01

    The effects of CO(2) enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO(2) concentration was elevated from 350 to 800 microl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO(2) concentration, N concentration, and CO(2)xN interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO(2). However, at 20 mmol N/L, elevated CO(2) had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO(2) concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO(2) concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO(2) condition.

  14. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)*

    Science.gov (United States)

    La, Gui-xiao; Fang, Ping; Teng, Yi-bo; Li, Ya-juan; Lin, Xian-yong

    2009-01-01

    The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L, elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition. PMID:19489111

  15. Supercritical CO2 Extraction of Lavandula angustifolia Mill. Flowers: Optimisation of Oxygenated Monoterpenes, Coumarin and Herniarin Content.

    Science.gov (United States)

    Jerković, Igor; Molnar, Maja; Vidović, Senka; Vladić, Jelena; Jokić, Stela

    2017-11-01

    Lavandula angustifolia is good source of oxygenated monoterpenes containing coumarins as well, which are all soluble in supercritical CO2 (SC-CO2 ). The study objective is to investigate SC-CO2 extraction parameters on: the total yield; GC-MS profile of the extracts; relative content of oxygenated monoterpenes; the amount of coumarin and herniarin; and to determine optimal SC-CO2 extraction conditions by response surface methodology (RSM). SC-CO2 extraction was performed under different pressure, temperature and CO2 flow rate determined by Box-Behnken design (BBD). The sample mass and the extraction time were kept constant. The chemical profiles and relative content of oxygenated monoterpenes (as coumarin equivalents, CE) were determined by GC-MS. Coumarin and herniarin concentrations were dosed by HPLC. SC-CO2 extracts contained linalool (57.4-217.9 mg CE/100 g), camphor (10.6-154.4 mg CE/100 g), borneol (6.2-99.9 mg CE/100 g), 1,8-cineole (5.0-70.4 mg CE/100 g), linalyl acetate (86.1-267.9 mg CE/100 g), coumarin (0.95-18.16 mg/100 g), and herniarin (0.95-13.63 mg/100 g). The interaction between the pressure and CO2 flow rate as well as between the temperature and CO2 flow rate showed statistically significant influence on the extraction yield. Applying BBD, the optimum extraction conditions for higher monoterpenes and lower coumarin content were at 10 MPa, 41°C and CO2 flow rate 2.3 kg/h, and at 30 MPa, 50°C and CO2 flow rate 3 kg/h for higher monoterpenes and coumarin content. SC-CO2 extraction is a viable technique for obtaining lavender extracts with desirable flavour components. The second-order model based on BBD predicts the results for SC-CO2 extraction quite satisfactorily. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  16. 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.

  17. [Effects of drought stress, high temperature and elevated CO2 concentration on the growth of winter wheat].

    Science.gov (United States)

    Si, Fu-Yan; Qiao, Yun-Zhou; Jiang, Jing-Wei; Dong, Bao-Di; Shi, Chang-Hai; Liu, Meng-Yu

    2014-09-01

    The impacts of climate change on the grain yield, photosynthesis, and water conditions of winter wheat were assessed based on an experiment, in which wheat plants were subjected to ambient and elevated CO2 concentrations, ambient and elevated temperatures, and low and high water conditions independently and in combination. The CO2 enrichment alone had no effect on the photosynthesis of winter wheat, whereas higher temperature and drought significantly decreased the photosynthetic rate. Water conditions in flag leaves were not significantly changed at the elevated CO2 concentration or elevated temperature. However, drought stress decreased the relative water content in flag leaves, and the combination of elevated temperature and drought reduced the water potential in flag leaves. The combination of elevated CO2 concentration, elevated temperature, and drought significantly reduced the photosynthetic rate and water conditions, and led to a 41.4% decrease in grain yield. The elevated CO2 concentration alone increased the grain yield by 21.2%, whereas the elevated temperature decreased the grain yield by 12.3%. The grain yield was not affected by the combination of elevated CO2 concentration and temperature, but the grain yield was significantly decreased by the drought stress if combined with any of the climate scenarios applied in this study. These findings suggested that maintaining high soil water content might be a vital means of reducing the potential harm caused by the climate change.

  18. 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

    High-resolution transmission spectra of CO2 in the 2.7,4.3 and 15 μm regions at temperatures up to 1773 K and at approximately atmospheric pressure (1.00 ± 0.01atm) are measured and compared with line-by-line calculations based on the HITEMP-1995, HITEMP-2010, CDSD-HITEMP and CDSD-4000 databases....... 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......-resolution data obtained by Bharadwaj and Modest [6]. The deviations between the experimental spectra and the calculations at 1773 K and the vibrational energy exchange and thermal dissociation of CO2 at high temperatures are discussed....

  19. Sun leaves up-regulate the photorespiratory pathway to maintain a high rate of CO2 assimilation in tobacco

    Directory of Open Access Journals (Sweden)

    Wei eHuang

    2014-12-01

    Full Text Available The greater rate of CO2 assimilation in sun-grown tobacco leaves leads to lower intercellular and chloroplast CO2 concentrations and, thus, a higher rate of oxygenation of ribulose-1,5-bisphosphate (RuBP than in shade-grown leaves. Impairment of the photorespiratory pathway suppresses photosynthetic CO2 assimilation. Here, we hypothesized that sun leaves can up-regulate photorespiratory pathway to enhance the rate of CO2 assimilation in tobacco. To test this hypothesis, we examined the responses of photosynthetic electron flow and CO2 assimilation to incident light intensity and intercellular CO2 concentration (Ci in leaves of ‘k326’ tobacco plants grown at 95% sunlight (sun plants or 28% sunlight (shade plants. The sun leaves had higher photosynthetic capacity and electron flow devoted to RuBP carboxylation (JC than the shade leaves. When exposed to high light, the higher Rubisco content and lower Ci in the sun leaves led to greater electron flow devoted to RuBP oxygenation (JO. The JO/JC ratio was significantly higher in the sun leaves than in the shade leaves under strong illumination. As estimated from CO2-response curves, the maximum JO was linearly correlated with the estimated Rubisco content. Based on light-response curves, the light-saturated JO was linearly correlated with light-saturated photosynthetic electron flow and light-saturated photosynthesis. These findings indicate that enhancement of the photorespiratory pathway is an important strategy by which sun plants maintain a high rate of CO2 assimilation.

  20. High storage rates of anthropogenic CO_{2} in the Indian sector of the Southern Ocean

    Science.gov (United States)

    Murata, Akihiko; Kumamoto, Yu-ichiro; Sasaki, Ken-ichi

    2017-04-01

    Using high-quality data for CO2-system and related properties collected 17 years apart through international observation programs, we examined decadal-scale increases of anthropogenic CO2 along a zonal section at nominal 62˚ S ranging from 30˚ E to 160˚ E in the Indian sector of the Southern Ocean. In contrast to previous studies, increases of anthropogenic CO2 were largest (> 9.0 μmol kg-1) in Antarctic Bottom Water, where little storage of anthropogenic CO2 has been reported. Significant increases of anthropogenic CO2 in bottom and/or deep waters were detected through the section, although they became reduced in magnitude and depth range west of 110˚ E. Vertical distributions of anthropogenic CO2 showed significant positive correlations with decadal-scale changes in CFC-12, a proxy of circulation and ventilation, meaning that the distributions were mainly controlled by physical processes. Comparison of increases of anthropogenic CO2 between calculation methods with and without total alkalinity presented differences of increases of anthropogenic CO2west of 50˚ E. This is probably because decreases in production of particulate inorganic carbons in the Southern Ocean. The highest storage rate of anthropogenic CO2 was estimated to be 1.1 ± 0.6 mol m-2 a-1 at longitudes 130˚ -160˚ E. The results highlight storage rates higher than ever reported in the Southern Ocean, where very low storage of anthropogenic CO2 has been evidenced.

  1. Highly efficient CO2 sorbents: development of synthetic, calcium-rich dolomites.

    Science.gov (United States)

    Filitz, Rainer; Kierzkowska, Agnieszka M; Broda, Marcin; Müller, Christoph R

    2012-01-03

    The reaction of CaO with CO(2) is a promising approach for separating CO(2) from hot flue gases. The main issue associated with the use of naturally occurring CaCO(3), that is, limestone, is the rapid decay of its CO(2) capture capacity over repeated cycles of carbonation and calcination. Interestingly, dolomite, a naturally occurring equimolar mixture of CaCO(3) and MgCO(3), possesses a CO(2) uptake that remains almost constant with cycle number. However, owing to the large quantity of MgCO(3) in dolomite, the total CO(2) uptake is comparatively small. Here, we report the development of a synthetic Ca-rich dolomite using a coprecipitation technique, which shows both a very high and a stable CO(2) uptake over repeated cycles of calcination and carbonation. To obtain such an excellent CO(2) uptake characteristic it was found to be crucial to mix the Ca(2+) and Mg(2+) on a molecular level, that is, within the crystalline lattice. For sorbents which were composed of mixtures of microscopic crystals of CaCO(3) and MgCO(3), a decay behavior similar to natural limestone was observed. After 15 cycles, the CO(2) uptake of the best sorbent was 0.51 g CO(2)/g sorbent exceeding the CO(2) uptake of limestone by almost 100%.

  2. High-Surface-Area CO2 Sponge: High Performance CO2 Scrubbing Based on Hollow Fiber-Supported Designer Ionic Liquid Sponges

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-09-01

    IMPACCT Project: The team from ORNL and Georgia Tech is developing a new technology that will act like a sponge, integrating a new, alcohol-based ionic liquid into hollow fibers (magnified image, right) to capture CO2 from the exhaust produced by coal-fired power plants. Ionic liquids, or salts that exist in liquid form, are promising materials for carbon capture and storage, but their tendency to thicken when combined with CO2 limits their efficiency and poses a challenge for their development as a cost-effective alternative to current-generation solutions. Adding alcohol to the mix limits this tendency to thicken in the presence of CO2 but can also make the liquid more likely to evaporate, which would add significantly to the cost of CO2 capture. To solve this problem, ORNL is developing new classes of ionic liquids with high capacity for absorbing CO2. ORNL’s sponge would reduce the cost associated with the energy that would need to be diverted from power plants to capture CO2 and release it for storage.

  3. 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.

  4. Evaluation of catalyst for closed cycle operation of high energy pulsed CO2 lasers

    Science.gov (United States)

    Rogowski, R. S.; Miller, I. M.; Wood, G.; Schryer, D. R.; Hess, R. V.; Upchurch, B. T.

    1983-01-01

    Several catalyst materials have been tested for efficiency of converting CO and O2 to CO2 for use in a high energy CO2 laser. The composition of the gas mixtures was monitored by mass spectrometry and gas chromatography. A copper/copper oxide catalyst and a platinum/tin oxide catalyst were used for closed cycle operation of a CO2 laser (0.7 joules/pulse), operating at 10 pulses/sec.

  5. Liquid-vapor equilibrium of the systems butylmethylimidazolium nitrate-CO2 and hydroxypropylmethylimidazolium nitrate-CO2 at high pressure: influence of water on the phase behavior.

    Science.gov (United States)

    Bermejo, M Dolores; Montero, Marta; Saez, Elisa; Florusse, Louw J; Kotlewska, Aleksandra J; Cocero, M José; van Rantwijk, Fred; Peters, Cor J

    2008-10-30

    Ionic liquids (IL) are receiving increasing attention due to their potential as "green" solvents, especially when used in combination with SC-CO2. In this work liquid-vapor equilibria of binary mixtures of CO2 with two imidazolium-based ionic liquids (IL) with a nitrate anion have been experimentally determined: butylmethylimidazolium nitrate (BMImNO3) and hydroxypropylmethylimidazolium nitrate (HOPMImNO3), using a Cailletet apparatus that operates according to the synthetic method. CO2 concentrations from 5 up to 30 mol % were investigated. It was found that CO2 is substantially less soluble in HOPMImNO3 than in BMImNO3. Since these ILs are very hygroscopic, water easily can be a major contaminant, causing changes in the phase behavior. In case these Ils are to be used in practical applications, for instance, together with CO2 as a medium in supercritical enzymatic reactions, it is very important to have quantitative information on how the water content will affect the phase behavior. This work presents the first systematic study on the influence of water on the solubility of carbon dioxide in hygroscopic ILs. It was observed that the presence of water reduces the absolute solubility of CO2. However, at fixed ratios of CO2/IL, the bubble point pressure remains almost unchanged with increasing water content. In order to explain the experimental results, the densities of aqueous mixtures of both ILs were determined experimentally and the excess molar volumes calculated.

  6. Study of the thermohydraulics of CO2 discharge from a high pressure reservoir

    NARCIS (Netherlands)

    Ahmad, M.; Osch, M.B.V.; Buit, L.; Florisson, O.; Hulsbosch-Dam, C.; Spruijt, M.; Davolio, F.

    2013-01-01

    An experimental test set up has been constructed to carry out controlled CO2 release experiments from a high pressure vessel. The test set up is made up of a 500l stainless steel vessel where CO2 can be introduced up to high pressures and where controlled releases can be conducted. The work

  7. 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.

  8. High resolution infrared spectroscopy of carbon dioxide clusters up to (CO2)13

    OpenAIRE

    Norooz Oliaee, J.; Dehghany, M.; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2011-01-01

    Thirteen specific infrared bands in the 2350 cm−1 region are assigned to carbon dioxide clusters, (CO2)N, with N = 6, 7, 9, 10, 11, 12 and 13. The spectra are observed in direct absorption using a tuneable infrared laser to probe a pulsed supersonic jet expansion of a dilute mixture of CO2 in He carrier gas. Assignments are aided by cluster structure calculations made using two reliable CO2 intermolecular potential functions. For (CO2)6, two highly symmetric isomers are observed, one with S6 ...

  9. Selective hydrolysis of wheat straw hemicellulose using high-pressure CO2 as catalyst 

    OpenAIRE

    Relvas, F.; Morais, Ana Rita; Bogel-Lukasik, R.

    2015-01-01

    The processing of wheat straw using high-pressure CO2–H2O technology was studied with the objective to evaluate the effect of CO2 as catalyst on the hydrothermal production of hemicellulose-derived sugars either as oligomers or as monomers. Also, the reduction of the crystallinity of the cellulose-rich fraction was assessed. Over a range of reaction conditions (0 to 50 bar of initial CO2 pressure and 0 to 45 minutes of holding time, at T ¼ 180 C), the addition of CO2 to water-based processes ...

  10. Hierarchical NiCo2 S4 Nanotube@NiCo2 S4 Nanosheet Arrays on Ni Foam for High-Performance Supercapacitors.

    Science.gov (United States)

    Chen, Haichao; Chen, Si; Shao, Hongyan; Li, Chao; Fan, Meiqiang; Chen, Da; Tian, Guanglei; Shu, Kangying

    2016-01-01

    Hierarchical NiCo2 S4 nanotube@NiCo2 S4 nanosheet arrays on Ni foam have been successfully synthesized. Owing to the unique hierarchical structure, enhanced capacitive performance can be attained. A specific capacitance up to 4.38 F cm(-2) is attained at 5 mA cm(-2) , which is much higher than the specific capacitance values of NiCo2 O4 nanosheet arrays, NiCo2 S4 nanosheet arrays and NiCo2 S4 nanotube arrays on Ni foam. The hierarchical NiCo2 S4 nanostructure shows superior cycling stability; after 5000 cycles, the specific capacitance still maintains 3.5 F cm(-2) . In addition, through the morphology and crystal structure measurement after cycling stability test, it is found that the NiCo2 S4 electroactive materials are gradually corroded; however, the NiCo2 S4 phase can still be well-maintained. Our results show that hierarchical NiCo2 S4 nanostructures are suitable electroactive materials for high performance supercapacitors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. From the low past to the high future: Plant growth across CO2 levels

    Science.gov (United States)

    Temme, Andries; Cornwell, Will; Cornelissen, Hans; Aerts, Rien

    2014-05-01

    In today's atmosphere fossil fuel emissions and land use change since the industrial revolution have increased atmospheric CO2 concentration from 280 ppm to nearly 400 ppm, a value not experienced by plants for over 10 million years. In contrast, over the same period atmospheric CO2 levels have been much lower than preindustrial levels. Plants' recent evolutionary history has thus been under carbon starvation while over the next 90 years atmospheric CO2 is expected to rise to a bountiful ~800 ppm. Plants' response to this rapid increase is likely influenced by their long evolution in low CO2, but this has been hardly studied at all. Very little is known about how plant traits drove carbon cycling in the past and how these relationships may shift going from past to future CO2.In a climate chamber experiment we germinated and grew seedlings of 30 species (C3, C4, woody, herbaceous) at past low CO2 (150ppm), ambient CO2, and future high CO2(750ppm). Our aim was to understand how plant traits are affected by CO2 and if and why winners and losers in terms of growth performance shift going from past to future CO2 concentrations. Results show a great effect of low and high CO2 on specific leaf area, biomass and allocation shifts above and belowground but mixed results in patterns between species and plant types. Ongoing work focuses on leaf level chemistry and photosynthesis and the interaction between CO2 and drought stress with promising initial results.

  12. Biocapture of CO2 from biogas by oleaginous microalgae for improving methane content and simultaneously producing lipid.

    Science.gov (United States)

    Tongprawhan, Wassa; Srinuanpan, Sirasit; Cheirsilp, Benjamas

    2014-10-01

    This study aimed to use oleaginous microalgae to capture CO2 from biogas for improving methane content and simultaneously producing lipid. Several microalgae were screened for their ability to grow and produce lipid using CO2 in biogas. A marine Chlorella sp. was the most suitable strain for capturing CO2 and producing lipid using biogas (50% v/v CO2 in methane) as well as using 50% v/v CO2 in air. The medium and operating conditions were optimized through response surface methodology (RSM). The optimal concentrations of KNO3 and K2HPO4 were 0.80gL(-1) and 0.06gL(-1), respectively. The optimal operating conditions were: initial pH of 7.8, initial cell concentration of 10(7.5)cellsmL(-1), light intensity of 4500lux and gas flow rate of 0.03Lmin(-1). After optimization, 89.3% of CO2 was removed from biogas and the methane content was increased up to 94.7%. The lipid productivity was 94.7mgL(-1)day(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Changes in growth, rRNA content, and cell morphology of Listeria monocytogenes induced by CO2 up- and downshift

    DEFF Research Database (Denmark)

    Jydegaard-Axelsen, A.M.; Aaes-Jorgensen, A.; Koch, A.G.

    2005-01-01

    unchanged. On sausage slices, the number of colony forming units also increased rapidly for both strains in response to CO2 downshift. Large variations in rRNA content of individual cells were observed in the tested scenarios. The results demonstrate the risk of underestimating the number of infectious......Cell morphology, rRNA content, and growth were examined for Listeria monocytogenes LO28 and EGD, respectively, grown in brain-heart infusion (BHI) and on slices of sausage at 10degreesC in 100% CO2, 100% N-2, and air. In CO2, filamentous cells were formed by both strains on sausage slices and by L...... in air and CO2.. Septation and cell division were induced in the filaments after a CO2 downshift (i.e., exposure to air). In BHI, the number of colony forming units increased rapidly when L. monocytogenes EGD grown in CO2 was exposed to air whereas the number of L. monocytogenes LO28 remained almost...

  14. 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

  15. A 5 cm single-discharge CO2 laser having high power output

    NARCIS (Netherlands)

    Ernst, G.J.; Boer, A.G.

    1980-01-01

    A single-discharge self-sustained CO2 laser has been constructed with a gap distance of 5 cm. The system has a very simple construction; it produces a very uniform discharge with an output power of 50 Joules per liter for a CO2 : N2 : He = 1 : 1 : 3 mixture. The efficiency can be as high as 19%.

  16. Reconstruction of a continuous high-resolution CO2 record over the past 20 million years

    NARCIS (Netherlands)

    van de Wal, R.S.W.|info:eu-repo/dai/nl/101899556; de Boer, B.|info:eu-repo/dai/nl/304023183; Lourens, L.|info:eu-repo/dai/nl/125023103; Köhler, P.; Bintanja, R.|info:eu-repo/dai/nl/127306757

    2011-01-01

    The gradual cooling of the climate during the Cenozoic has generally been attributed to a decrease in CO2 concentration in the atmosphere. The lack of transient climate models and, in particular, the lack of high-resolution proxy records of CO2, beyond the ice-core record prohibit, however, a full

  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. Experimental determination of CO2 content at graphite saturation along a natural basalt-peridotite melt join: Implications for the fate of carbon in terrestrial magma oceans

    Science.gov (United States)

    Duncan, Megan S.; Dasgupta, Rajdeep; Tsuno, Kyusei

    2017-05-01

    Knowledge of the carbon carrying capacity of peridotite melt at reducing conditions is critical to constrain the mantle budget and planet-scale distribution of carbon set at early stage of differentiation. Yet, neither measurements of CO2 content in reduced peridotite melt nor a reliable model to extrapolate the known solubility of CO2 in basaltic (mafic) melt to solubility in peridotitic (ultramafic) melt exist. There are several reasons for this gap; one reason is due to the unknown relative contributions of individual network modifying cations, such as Ca2+ versus Mg2+, on carbonate dissolution particularly at reducing conditions. Here we conducted high pressure, temperature experiments to estimate the CO2 contents in silicate melts at graphite saturation over a compositional range from natural basalts toward peridotite at a fixed pressure (P) of 1.0 GPa, temperature (T) of 1600 °C, and oxygen fugacity (log ⁡ fO2 ∼ IW + 1.6). We also conducted experiments to determine the relative effects of variable Ca and Mg contents in mafic compositions on the dissolution of carbonate. Carbon in quenched glasses was measured and characterized using Fourier transform infrared spectroscopy (FTIR) and Raman Spectroscopy and was found to be dissolved as carbonate (CO32-). The FTIR spectra showed CO32- doublets that shifted systematically with the MgO and CaO content of silicate melts. Using our data and previous work we constructed a new composition-based model to determine the CO2 content of ultramafic (peridotitic) melt representative of an early Earth, magma ocean composition at graphite saturation. Our data and model suggest that the dissolved CO2 content of reduced, peridotite melt is significantly higher than that of basaltic melt at shallow magma ocean conditions; however, the difference in C content between the basaltic and peridotitic melts may diminish with depth as the more depolymerized peridotite melt is more compressible. Using our model of CO2 content at

  19. High-frequency analysis of the complex linkage between soil CO(2) fluxes, photosynthesis and environmental variables.

    Science.gov (United States)

    Martin, Jonathan G; Phillips, Claire L; Schmidt, Andres; Irvine, James; Law, Beverly E

    2012-01-01

    High-frequency soil CO(2) flux data are valuable for providing new insights into the processes of soil CO(2) production. A record of hourly soil CO(2) fluxes from a semi-arid ponderosa pine stand was spatially and temporally deconstructed in attempts to determine if variation could be explained by logical drivers using (i) CO(2) production depths, (ii) relationships and lags between fluxes and soil temperatures, or (iii) the role of canopy assimilation in soil CO(2) flux variation. Relationships between temperature and soil fluxes were difficult to establish at the hourly scale because diel cycles of soil fluxes varied seasonally, with the peak of flux rates occurring later in the day as soil water content decreased. Using a simple heat transport/gas diffusion model to estimate the time and depth of CO(2) flux production, we determined that the variation in diel soil CO(2) flux patterns could not be explained by changes in diffusion rates or production from deeper soil profiles. We tested for the effect of gross ecosystem productivity (GEP) by minimizing soil flux covariance with temperature and moisture using only data from discrete bins of environmental conditions (±1 °C soil temperature at multiple depths, precipitation-free periods and stable soil moisture). Gross ecosystem productivity was identified as a possible driver of variability at the hourly scale during the growing season, with multiple lags between ~5, 15 and 23 days. Additionally, the chamber-specific lags between GEP and soil CO(2) fluxes appeared to relate to combined path length for carbon flow (top of tree to chamber center). In this sparse and heterogeneous forested system, the potential link between CO(2) assimilation and soil CO(2) flux may be quite variable both temporally and spatially. For model applications, it is important to note that soil CO(2) fluxes are influenced by many biophysical factors, which may confound or obscure relationships with logical environmental drivers and act at

  20. Estimating respiration of roots in soil: interactions with soil CO2, soil temperature and soil water content

    NARCIS (Netherlands)

    Bouma, T.J.; Nielsen, K.F.; Eissenstat, D.M.; Lynch, J.P.

    1997-01-01

    Little information is available on the variability of the dynamics of the actual and observed root respiration rate in relation to abiotic factors. In this study, we describe I) interactions between soil CO2 concentration, temperature, soil water content and root respiration, and II) the effect of

  1. Gain kinetics of CO2 gasdynamic laser mixtures at high pressure.

    Science.gov (United States)

    Christiansen, W. H.; Tsongas, G. A.

    1971-01-01

    Description of a combined analytical and experimental investigation of rapidly expanded CO2 laser mixtures. Study of the vibrational kinetics indicates that population inversions with high vibrational energy density can be produced at high pressures by utilizing low (starved) concentrations of CO2. Scaling laws for predicting the gain of starved systems are developed. A description is given of gain measurements carried out using a CO2 laser to probe the flow in a nozzle at the point where the Mach number is approximately four. Population inversions at static pressures as high as about 1 atm have been observed and found to be in reasonable agreement with predictions.

  2. 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

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

    KAUST Repository

    Qi, Genggeng

    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.

  4. High Pressure Behavior of Precompressed CO2 Shocked to 10 Mbar

    Science.gov (United States)

    Crandall, L.; Rygg, J. R.; Collins, G. W.; Boehly, T. R.; Jenei, A.; Fratanduono, D. E.; Gregor, M. C.; Eggert, J. H.; Millot, M.; Spaulding, D.

    2017-10-01

    CO2 is present in the atmospheres and interiors of Jovian planets, atmospheres of exoplanets, and within Jovian moons. To study the high-pressure behavior of CO2, we used laser-driven shocks to compress CO2, to 1 TPa (10 Mbar). The CO2 was precompressed in diamond-anvil cells to 5 kbar, producing liquid at density ( 1.5 ggcm3 cm3) , and then shocked by the OMEGA Laser System. Equation of state, temperature, and optical reflectivity were measured between 150 and 950 GPa. CO2 undergoes an insulator-to-conductor transition above 200 GPa, which may be result from dissociation to metallic oxygen. These data can add to understanding of thermochemical histories of the giant planets. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Technology assessment of high pulse energy CO(2) lasers for remote sensing from satellites

    Science.gov (United States)

    Hess, R. V.; Brockman, P.; Schryer, D. R.; Miller, I. M.; Bair, C. H.; Sidney, B. D.; Wood, G. M.; Upchurch, B. T.; Brown, K. G.

    1985-01-01

    Developments and needs for research to extend the lifetime and optimize the configuration of CO2 laser systems for satellite based on remote sensing of atmospheric wind velocities and trace gases are reviewed. The CO2 laser systems for operational satellite application will require lifetimes which exceed 1 year. Progress in the development of efficient low temperature catalysts and gas mixture modifications for extending the lifetime of high pulse energy closed cycle common and rare isotope CO2 lasers and of sealed CW CO2 lasers is reviewed. Several CO2 laser configurations are under development to meet the requirements including: unstable resonators, master oscillator power amplifiers and telescopic stable resonators, using UV or E-beam preionization. Progress in the systems is reviewed and tradeoffs in the system parameters are discussed.

  6. 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.

  7. Energy balance in high-power CO2 laser welding

    Science.gov (United States)

    Del Bello, Umberto; Rivela, Cristina; Cantello, Maichi; Penasa, Mauro

    1991-10-01

    The laser energy impinging on a metal workpiece is partially absorbed and partially reflected by the material surface. This work is aimed at gaining a better insight into the energy balance of the process, and it can also provide the correct input for process modeling and the optimum choice of parameters for increasing welding efficiency. Measurements of the absorption coefficient were made using platinum-platinum rhodium thermocouples which monitored the temperature rise. The radiation backscattered by the workpiece or plasma plume was also recorded, and tests were performed to measure the total amount of material lost by evaporation during laser welding. All the tests were performed on austenitic stainless steel. The resulting absorption curves show different behavior at low or high speed and this can be explained only by taking into account the influence on the process of both the size and inclination of the keyhole. To conserve the keyhole, the interaction process must be rapidly interrupted so as to freeze the molten material and preserve the cavity in the form assumed during the process. A fast mechanical switch has been devised and tests seem to confirm the assumption made.

  8. 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.

  9. 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.

  10. Leaf day respiration: low CO2 flux but high significance for metabolism and carbon balance.

    Science.gov (United States)

    Tcherkez, Guillaume; Gauthier, Paul; Buckley, Thomas N; Busch, Florian A; Barbour, Margaret M; Bruhn, Dan; Heskel, Mary A; Gong, Xiao Ying; Crous, Kristine Y; Griffin, Kevin; Way, Danielle; Turnbull, Matthew; Adams, Mark A; Atkin, Owen K; Farquhar, Graham D; Cornic, Gabriel

    2017-12-01

    Contents 986 I. 987 II. 987 III. 988 IV. 991 V. 992 VI. 995 VII. 997 VIII. 998 References 998 SUMMARY: It has been 75 yr since leaf respiratory metabolism in the light (day respiration) was identified as a low-flux metabolic pathway that accompanies photosynthesis. In principle, it provides carbon backbones for nitrogen assimilation and evolves CO2 and thus impacts on plant carbon and nitrogen balances. However, for a long time, uncertainties have remained as to whether techniques used to measure day respiratory efflux were valid and whether day respiration responded to environmental gaseous conditions. In the past few years, significant advances have been made using carbon isotopes, 'omics' analyses and surveys of respiration rates in mesocosms or ecosystems. There is substantial evidence that day respiration should be viewed as a highly dynamic metabolic pathway that interacts with photosynthesis and photorespiration and responds to atmospheric CO2 mole fraction. The view of leaf day respiration as a constant and/or negligible parameter of net carbon exchange is now outdated and it should now be regarded as a central actor of plant carbon-use efficiency. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  11. Coastal CO2 climatology of Oahu, Hawaii: Six years of high resolution time-series data

    Science.gov (United States)

    Terlouw, G. J.; Drupp, P. S.; De Carlo, E. H.; Tomlinson, M.

    2014-12-01

    Six years of high resolution pCO2, water quality, and meteorological data were used to calculate air-sea CO2 fluxes on yearly, seasonal and monthly timescales, and relate the temporal and spatial variation in CO2 fluxes to meteorological events and land derived inputs. Three MAPCO2 buoys are deployed in coastal waters of Oahu as part of the NOAA/PMEL Carbon Program, that autonomously collects CO2 and water quality data at 3-hour intervals. The buoys are located on a backreef in Kaneohe Bay and two fringing reef sites on Oahu's south shore, the latter two in open ocean like conditions but with one also influenced by fluvial inputs. Data for this study were collected from June 2008 to July 2014. Mean pCO2 values at the Ala Wai, Kilo Nalu and CRIMP2 buoys were 396, 381 and 447μatm, respectively, with mean daily ranges of 51, 32 and 190 μatm, respectively. The daily range in pCO2 is largest at CRIMP2, reflecting a combination of higher primary production and respiration, vigorous calcification and longer water residence time within the barrier reef environment. Net annualized air-sea CO2 fluxes of the entire study period were 0.083, -0.014 and 1.167 mol C m-2 year-1 for Ala Wai, Kilo Nalu and CRIMP2, respectively. Positive values indicate a CO2 flux from the water to the atmosphere (source behavior), and negative values from the atmosphere to the water (sink behavior). This presentation will also discuss the effects physical and biogeochemical processes on the magnitude and variability of air-sea CO2 fluxes. We observe a negative correlation between CO2 flux and rainfall over monthly, seasonal, and annual timescales. This correlation however, can partly be explained by temperature, because increased rainfall is more common during the colder winter months. Nevertheless, rainfall affects CO2 fluxes, both by rain-induced nutrient and organic matter runoff, as well as the physical effect of raindrops on air-sea gas exchange and the dilution of the air-sea boundary layer

  12. Development and evaluation of a high sensitivity dial system for profiling atmospheric CO2

    Science.gov (United States)

    Ismail, S.; Koch, G. J.; Refaat, T.; Abedin, M. N.; Yu, J.; Singh, U. N.

    2017-11-01

    A ground-based 2-micron Differential Absorption Lidar (DIAL) CO2 profiling system for atmospheric boundary layer studies and validation of space-based CO2 sensors is being developed and tested at NASA Langley Research Center as part of the NASA Instrument Incubator Program. To capture the variability of CO2 in the lower troposphere a precision of 1-2 ppm of CO2 ( laser technology developed under NASA's Laser Risk Reduction Program (LRRP) and other NASA programs to develop new solid-state laser technology that provides high pulse energy, tunable, wavelength-stabilized, and double-pulsed lasers that are operable over pre-selected temperature insensitive strong CO2 absorption lines suitable for profiling of lower tropospheric CO2. It also incorporates new high quantum efficiency, high gain, and relatively low noise phototransistors, and a new receiver/signal processor system to achieve high precision DIAL measurements. This presentation describes the capabilities of this system for atmospheric CO2 and aerosol profiling. Examples of atmospheric measurements in the lidar and DIAL mode will be presented.

  13. High energy 2-micron solid-state laser transmitter for NASA's airborne CO2 measurements

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Bai, Yingxin

    2017-11-01

    A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

  14. Mapping of CO2 at High Spatiotemporal Resolution using Satellite Observations: Global distributions from OCO-2

    Science.gov (United States)

    Hammerling, Dorit M.; Michalak, Anna M.; Kawa, S. Randolph

    2012-01-01

    Satellite observations of CO2 offer new opportunities to improve our understanding of the global carbon cycle. Using such observations to infer global maps of atmospheric CO2 and their associated uncertainties can provide key information about the distribution and dynamic behavior of CO2, through comparison to atmospheric CO2 distributions predicted from biospheric, oceanic, or fossil fuel flux emissions estimates coupled with atmospheric transport models. Ideally, these maps should be at temporal resolutions that are short enough to represent and capture the synoptic dynamics of atmospheric CO2. This study presents a geostatistical method that accomplishes this goal. The method can extract information about the spatial covariance structure of the CO2 field from the available CO2 retrievals, yields full coverage (Level 3) maps at high spatial resolutions, and provides estimates of the uncertainties associated with these maps. The method does not require information about CO2 fluxes or atmospheric transport, such that the Level 3 maps are informed entirely by available retrievals. The approach is assessed by investigating its performance using synthetic OCO-2 data generated from the PCTM/ GEOS-4/CASA-GFED model, for time periods ranging from 1 to 16 days and a target spatial resolution of 1deg latitude x 1.25deg longitude. Results show that global CO2 fields from OCO-2 observations can be predicted well at surprisingly high temporal resolutions. Even one-day Level 3 maps reproduce the large-scale features of the atmospheric CO2 distribution, and yield realistic uncertainty bounds. Temporal resolutions of two to four days result in the best performance for a wide range of investigated scenarios, providing maps at an order of magnitude higher temporal resolution relative to the monthly or seasonal Level 3 maps typically reported in the literature.

  15. Whole-plant growth and N utilization in transgenic rice plants with increased or decreased Rubisco content under different CO2 partial pressures.

    Science.gov (United States)

    Sudo, Emi; Suzuki, Yuji; Makino, Amane

    2014-11-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) strongly limits photosynthesis at lower CO2 concentration [CO2] whereas [corrected] Rubisco limitation is cancelled by elevated [CO2]. Therefore, increase or reduction in Rubisco content by transformation with a sense or an antisense RBCS construct are expected to alter the biomass production under different CO2 levels. RBCS-sense (125% Rubisco of wild-type) and -antisense (35% Rubisco of wild-type) rice (Oryza sativa L.) plants were grown for 63 days at three different CO2 levels: low [CO2] (28 Pa), normal [CO2] (40 Pa) and elevated [CO2] (120 Pa). The biomass of RBCS-sense plants was 32% and 15% greater at low [CO2] and normal [CO2] than that of the wild-type plants, respectively, but did not differ at elevated [CO2]. Conversely, the biomass of RBCS-antisense plants was the smallest at low [CO2]. Thus, overproduction of Rubisco was effective for biomass production at low [CO2]. Greater biomass production at low [CO2] in RBCS-sense plants was caused by an increase in the net assimilation rate, and associated with an increase in the amount of N uptake. Furthermore, Rubisco overproduction in RBCS-sense plants was also promoted at low [CO2]. Although it seems that low [CO2]-growth additionally stimulates the effect of RBCS overexpression, such a phenomenon observed at low [CO2] was mediated through an increase in total leaf N content. Thus, the dependence of the growth improvement in RBCS-sense rice on growth [CO2] was closely related to the degree of Rubisco overproduction which was accompanied not only by leaf N content but also by whole plant N content. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. 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.

  17. 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.

  18. Ultrathin Composite Polymeric Membranes for CO2/N2Separation with Minimum Thickness and High CO2Permeance.

    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.

  19. Variation in Yield Responses to Elevated CO2 and a Brief High Temperature Treatment in Quinoa

    Science.gov (United States)

    Bunce, James A.

    2017-01-01

    Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient”) and 600 (“elevated”) μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control”) temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures) for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control) or increased (1.70 × control) seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined. PMID:28678208

  20. Variation in Yield Responses to Elevated CO2 and a Brief High Temperature Treatment in Quinoa

    Directory of Open Access Journals (Sweden)

    James A. Bunce

    2017-07-01

    Full Text Available Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient” and 600 (“elevated” μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control” temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control or increased (1.70 × control seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined.

  1. Reconstruction of a continuous high-resolution CO2 record over the past 20 million years

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2011-12-01

    Full Text Available The gradual cooling of the climate during the Cenozoic has generally been attributed to a decrease in CO2 concentration in the atmosphere. The lack of transient climate models and, in particular, the lack of high-resolution proxy records of CO2, beyond the ice-core record prohibit, however, a full understanding of, for example, the inception of the Northern Hemisphere glaciation and mid-Pleistocene transition. Here we elaborate on an inverse modelling technique to reconstruct a continuous CO2 series over the past 20 million year (Myr, by decomposing the global deep-sea benthic δ18O record into a mutually consistent temperature and sea level record, using a set of 1-D models of the major Northern and Southern Hemisphere ice sheets. We subsequently compared the modelled temperature record with ice core and proxy-derived CO2 data to create a continuous CO2 reconstruction over the past 20 Myr. Results show a gradual decline from 450 ppmv around 15 Myr ago to 225 ppmv for mean conditions of the glacial-interglacial cycles of the last 1 Myr, coinciding with a gradual cooling of the global surface temperature of 10 K. Between 13 to 3 Myr ago there is no long-term sea level variation caused by ice-volume changes. We find no evidence of change in the long-term relation between temperature change and CO2, other than the effect following the saturation of the absorption bands for CO2. The reconstructed CO2 record shows that the Northern Hemisphere glaciation starts once the long-term average CO2 concentration drops below 265 ppmv after a period of strong decrease in CO2. Finally, only a small long-term decline of 23 ppmv is found during the mid-Pleistocene transition, constraining theories on this major transition in the climate system. The approach is not accurate enough to revise current ideas about climate sensitivity.

  2. 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.

  3. 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.

  4. Engineering Carbon-Based Porous Materials from Selected Precursors for High-Capacity CO2 Capture

    OpenAIRE

    Zhu, B

    2015-01-01

    The mitigation of climate change is one of the major global challenges in the 21st Century. Carbon capture and storage (CCS) is a promising technology to effectively reduce anthropogenic CO2 emissions into the Earth’s atmosphere. There are various candidate materials for CO2 capture but each has its own advatanges and disadvantages. Carbon-based materials are of low-cost and have relatively high cyclicity for CO2 and its porous structure and surface functional groups can be tailored to improv...

  5. Experimental study of CO2 dissolution a convection phenomenon at high pressure

    Science.gov (United States)

    Ben Salem, Imen; Chevalier, Sylvie; Faisal, Titly Farhana; Abderrahmane, Hamid; Sassi, Mohamed

    2016-05-01

    The density driven convection phenomenon has a significant role in enhancing the CO2 geological storage capacity. Deep saline aquifers are targeted for large scale geological sequestration. Once the CO2 is injected in saline aquifer, the supercritical CO2 rises up, forms a thin layer of free phase CO2, and the dissolution and molecular diffusion of the dissolved CO2 in brine begins. The CO2 saturated brine is denser than the original brine leading to gravitational convection of CO2 saturated brine. Convection accelerates the dissolution process and thus improves the safety and the efficiency of the sequestration. Laboratory experiments have been previously performed with experimental set-ups allowing the visualization of the phenomenon (1) eventually combined to the measurements of the dissolved CO2 mass transfer (2) as a function of the permeability of the medium. The visualization of the process was possible as Hele-Shaw cells at atmospheric pressure were used. Pressurized cylindrical vessel containing porous media allows measuring mass transfer of CO2 using the pressure decay concept (3) but visualization of the convection/dissolution was not possible for these setups. In this work, we performed experiments in a pressurized transparent cell similar to a Hele-Shaw cell but with bigger aperture. Permeability was varied by changing the size of the glass beads filling the cell. Bromocrysol green was used as a dye to track the pH change due to the presence of dissolved CO2 (1). The phenomenon is captured by a high resolution camera. We studied the effect of the pressure and of the permeability on the fingering pattern, the onset and the timescale of the phenomenon and the quantitative mass transfer of dissolved CO2. Experiments were validated on numerical simulations performed using STOMP (Subsurface Transport Over Multiple Phases) developed by the PNNL (Pacific Northwest National Laboratory) Hydrology group of the Department of Energy, USA. (1) Kneafsey, T

  6. Cu-CDots nanocorals as electrocatalyst for highly efficient CO2 reduction to formate.

    Science.gov (United States)

    Guo, Sijie; Zhao, Siqi; Gao, Jin; Zhu, Cheng; Wu, Xiuqin; Fu, Yijun; Huang, Hui; Liu, Yang; Kang, Zhenhui

    2017-01-07

    Electrochemical reduction of CO2 is a key component of many prospective artificial technologies for renewable carbon-containing fuels, but it still suffers from the high overpotentials required to drive the process, low selectivity for diversiform products and the high cost of the catalyst. Here, we report that Cu-CDots nanocorals is a highly efficient, low-cost and stable electrocatalyst for CO2 reduction in aqueous solution. The major product of CO2 reduction on the Cu-CDots nanocorals is HCOOH with an inconceivable low overpotential of 0.13 V and a high Faraday efficiency of 79% at a moderate potential of -0.7 V vs. RHE. In the present system, CDots can increase the adsorption capacity of CO2 molecules and H+, which play important roles in CO2 reduction. The high selectivity of HCOOH for CO2 reduction may be ascribed to that CDots can greatly diminish the HCOOH desorption energy and improve the catalytic selectivity for HCOOH. Furthermore, Cu-CDots nanocorals exhibit a long-term stability during 5 h-electrolysis.

  7. High temporal resolution tracing of xylem CO2 transport in oak trees

    Science.gov (United States)

    Bloemen, Jasper; Ingrisch, Johannes; Bahn, Michael

    2016-04-01

    Carbon (C) allocation defines the flows of C between plant organs and their storage pools and metabolic processes and is therefore considered as an important determinant of forest C budgets and their responses to climate change. In trees, assimilates derived from leaf photosynthesis are transported via the phloem to above- and belowground sink tissues, where partitioning between growth, storage, and respiration occurs. At the same time, root- and aboveground respired CO2 can be dissolved in water and transported in the xylem tissue, thereby representing a C flux of large magnitude whose role in C allocation yet is unresolved. In this study, we infused 13C labeled water into the stem base of five year old potted oak (Quercus rubra) trees as a surrogate for respired CO2 to investigate the role of respired CO2 transport in trees in C allocation. We used high-resolution laser-based measurements of the isotopic composition of stem and soil CO2 efflux combined with stem gas probes to monitor the transport of 13C label. The high enrichment of the gas probes in the stem at the bottom of the canopy showed that the label was transported upwards from the base of the tree toward the top. During its ascent, the 13C label was removed from the transpiration stream and lost to the atmosphere at stem level, as was observed using the stem CO2 efflux laser-based measurements. This study is the first to show results from tracing xylem CO2 transport in trees at high temporal resolution using a 13C labeling approach. Moreover, they extend results from previous studies on internal CO2 transport in species with high transpiration rates like poplar to species with lower transpiration rates like oak. Internal transport of CO2 indicates that the current concepts of the tree C allocation need to be revisited, as they show that current gas exchange approach to estimating above- and belowground autotrophic respiration is inadequate.

  8. Highly efficient electro-reduction of CO2 to formic acid by nano-copper

    OpenAIRE

    Gupta, K; Bersani, M.; Darr, J. A.

    2016-01-01

    Ultra-fine copper(II) oxide nanoparticles were used for the electrocatalytic reduction of CO2 to formic acid at high Faradaic efficiencies. The nanoparticles were directly synthesised via continuous hydrothermal flow synthesis (CHFS) process, which used water as a solvent and reagent. The as-prepared nanoparticles were subsequently formulated into Nafion based inks. For the electroreduction of CO2, the influence of Nafion fraction on the Faradaic efficiencies and overpotential (for formic aci...

  9. Phosphoenolpyruvate carboxylase from cherimoya fruit: properties, kinetics and effects of high CO(2).

    Science.gov (United States)

    Muñoz, T; Escribano, M I; Merodio, C

    2001-12-01

    Phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) regulatory properties were studied in non-photosynthetic (mesocarp) and photosynthetic (peel) tissues from cherimoya (Annona cherimola Mill.) fruit stored in air, in order to gain a better understanding of in vivo enzyme regulation. Analyses were also performed with fruit treated with 20% CO(2)-20% O(2) to define the role of PEPC as part of an adaptive mechanism to high external carbon dioxide levels. The results revealed that the special kinetic characteristics of the enzyme from mesocarp--high V(max) and low sensibility to L-malate inhibition - are related to the active acid metabolism of these fruits and point to a high rate of reassimilation of respired CO(2) into keto-acids. With respect to fruit stored in air, PEPC in crude extracts from CO(2)-treated cherimoyas gave a similar V(max) (1.12+/-0.03 microkat x mg(-1) protein), a lower apparent K(m) (68+/-9 microM for PEP) and a higher I(50) of L-malate (5.95+/-0.3 mM). These kinetic values showed the increase in the affinity of this enzyme toward one of its substrate, PEP, by elevated external CO(2) concentrations. The lower K(m) value and lower sensitivity to L-malate are consistent with higher in vivo carboxylation reaction efficiency in CO(2)-treated cherimoyas, while pointing to an additional enzyme regulation system via CO(2).

  10. A global coupled Eulerian-Lagrangian model and 1 × 1 km CO2 surface flux dataset for high-resolution atmospheric CO2 transport simulations

    Directory of Open Access Journals (Sweden)

    R. Toumi

    2012-02-01

    Full Text Available We designed a method to simulate atmospheric CO2 concentrations at several continuous observation sites around the globe using surface fluxes at a very high spatial resolution. The simulations presented in this study were performed using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA, comprising a Lagrangian particle dispersion model coupled to a global atmospheric tracer transport model with prescribed global surface CO2 flux maps at a 1 × 1 km resolution. The surface fluxes used in the simulations were prepared by assembling the individual components of terrestrial, oceanic and fossil fuel CO2 fluxes. This experimental setup (i.e. a transport model running at a medium resolution, coupled to a high-resolution Lagrangian particle dispersion model together with global surface fluxes at a very high resolution, which was designed to represent high-frequency variations in atmospheric CO2 concentration, has not been reported at a global scale previously. Two sensitivity experiments were performed: (a using the global transport model without coupling to the Lagrangian dispersion model, and (b using the coupled model with a reduced resolution of surface fluxes, in order to evaluate the performance of Eulerian-Lagrangian coupling and the role of high-resolution fluxes in simulating high-frequency variations in atmospheric CO2 concentrations. A correlation analysis between observed and simulated atmospheric CO2 concentrations at selected locations revealed that the inclusion of both Eulerian-Lagrangian coupling and high-resolution fluxes improves the high-frequency simulations of the model. The results highlight the potential of a coupled Eulerian-Lagrangian model in simulating high-frequency atmospheric CO2 concentrations at many locations worldwide. The model performs well in representing observations of atmospheric CO2 concentrations at high spatial and temporal resolutions, especially for coastal sites and sites located close to

  11. Highly efficient CO 2 bubble removal on carbon nanotube supported nanocatalysts for direct methanol fuel cell

    Science.gov (United States)

    Chen, Soon-Lin; Lin, Chun-Ting; Chieng, Ching-Chang; Tseng, Fan-Gang

    In this paper, we investigate the CO 2 microbubble removal on carbon nanotube (CNT)-supported Pt catalysts in direct methanol fuel cells (DMFCs). The experiments involve the incorporation of near-catalyst-layer bubble visualization and simultaneous electrochemical measurements in a DMFC anodic half cell system, in which CH 3OH electro-oxidation generate carbon dioxide (CO 2) microbubbles. We observe rapid removal of smaller CO 2 bubble sizes and less bubble accumulation on a Pt-coated CNT/CC (Pt/CNT/CC, CC means carbon cloth) electrode. The improved half cell performances of the high CO 2 microbubble removal efficiency on the CNT-modified electrode (Pt/CNT/CC) were 34% and 32% higher than on Pt/CC and Pt/CP electrodes, respectively.

  12. Wettability characteristics of carbon steel modified with CO2, Nd:YAG, Excimer and high power diode lasers

    OpenAIRE

    Lawrence, Jonathan; Li, Lin

    2000-01-01

    Interaction of CO2, Nd:YAG, excimer and high power diode laser (HPDL) radiation with the surface of a common mild steel (EN8) was found to effect changes in the wettability characteristics of the steel, namely changes in the measured contact angle. These modifications are related to changes in the surface roughness, changes in the surface oxygen content and changes in the surface energy of the mild steel. The wettability characteristics of the selected mild steel could be controll...

  13. The BErkeley Atmospheric CO2 Observation Network: design, calibration, and initial evaluation of a high-density CO2 surface network

    Science.gov (United States)

    Shusterman, A.; Teige, V.; Turner, A. J.; Newman, C.; Kim, J.; Cohen, R. C.

    2016-12-01

    Conventionally, ground-based carbon dioxide monitoring efforts rely on a small handful of costly instruments scattered thinly across large domains. While well characterizing total integrated emissions originating from a given metropolitan area, such approaches are ill suited to resolve the heterogeneous patterns of urban CO2 sources occurring within the domain, despite the fact that these sources are often regulated individually and independently of the regional total. To better observe said heterogeneities, we present the BErkeley Atmospheric CO2 Observation Network (BEACO2N), an ensemble of 28 moderate-cost CO2 and air quality sensing "nodes" distributed across and around the city of Oakland, California at 2 km intervals, constituting what is, to our knowledge, the highest density CO2 monitoring network to date. We evaluate the network on the basis of four performance parameters (cost, reliability, precision, and bias) and derive various post hoc mathematical treatments to compensate for the deleterious effects of meteorological variability, temporal drift, and uncharacterized atemporal biases on the sensor data. We find our approach to dependably provide observations of sufficient quality to faithfully represent intra-city phenomena while nonetheless remaining cost-competitive with sparser networks of more expensive instruments. Furthermore, preliminary analyses of the first three years of observations reveal small scale variability in CO2 concentrations that cannot be accurately captured by current mesoscale modeling techniques, reinforcing the importance of such high resolution top-down observational methodologies to our understanding of urban CO2 on the actual scales of emission and regulation.

  14. Mutate Chlorella sp. by nuclear irradiation to fix high concentrations of CO2.

    Science.gov (United States)

    Cheng, Jun; Huang, Yun; Feng, Jia; Sun, Jing; Zhou, Junhu; Cen, Kefa

    2013-05-01

    To improve biomass productivity and CO2 fixation of microalgae under 15% (v/v) CO2 of flue gas, Chlorella species were mutated by nuclear irradiation and domesticated with high concentrations of CO2. The biomass yield of Chlorella pyrenoidosa mutated using 500 Gy of (60)Co γ irradiation increased by 53.1% (to 1.12 g L(-1)) under air bubbling. The mutants were domesticated with gradually increased high concentrations of CO2 [from 0.038% (v/v) to 15% (v/v)], which increased the biomass yield to 2.41 g L(-1). When light transmission and culture mixing in photo-bioreactors were enhanced at 15% (v/v) CO2, the peak growth rate of the domesticated mutant (named Chlorella PY-ZU1) was increased to 0.68 g L(-1) d(-1). When the ratio of gas flow rate (L min(-1)) to 1L of microalgae culture was 0.011, the peak CO2 fixation rate and the efficiency of Chlorella PY-ZU1 were 1.54 g L(-1) d(-1) and 32.7%, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Winter-time CO2 addition in high rate algal mesocosms for enhanced microalgal performance.

    Science.gov (United States)

    Sutherland, Donna L; Montemezzani, Valerio; Mehrabadi, Abbas; Craggs, Rupert J

    2016-02-01

    Carbon limitation in domestic wastewater high rate algal ponds is thought to constrain microalgal photo-physiology and productivity and CO2 augmentation is often used to overcome this limitation in summer. However, the implications of carbon limitation during winter are poorly understood. This paper investigates the effects of 0.5%, 2%, 5% and 10% CO2 addition on the winter-time performance of wastewater microalgae in high rate algal mesocosms. Performance was measured in terms of light absorption, photosynthetic efficiency, biomass production and nutrient removal rates, along with community composition. Varying percentage CO2 addition and associated change in culture pH resulted in 3 distinct microalgal communities. Light absorption by the microalgae increased by up to 144% with CO2 addition, while a reduction in the package effect meant that there was less internal self-shading thereby increasing the efficiency of light absorption. Carbon augmentation increased the maximum rate of photosynthesis by up to 172%, which led to increased microalgal biovolume by up to 181% and an increase in total organic biomass for all treatments except 10% CO2. While 10% CO2 improved light absorption and photosynthesis this did not translate to enhanced microalgal productivity. Increased microalgal productivity with CO2 addition did not result in increased dissolved nutrient (nitrogen and phosphorus) removal. This experiment demonstrated that winter-time carbon augmentation up to 5% CO2 improved microalgal light absorption and utilisation, which ultimately increased microalgal biomass and is likely to enhance total annual microalgal areal productivity in HRAPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Influence of ameliorating soil acidity with dolomite on the priming of soil C content and CO2 emission.

    Science.gov (United States)

    Shaaban, Muhammad; Wu, Lei; Peng, Qi-An; van Zwieten, Lukas; Chhajro, Muhammad Afzal; Wu, Yupeng; Lin, Shan; Ahmed, Muhammad Mahmood; Khalid, Muhammad Salman; Abid, Muhammad; Hu, Ronggui

    2017-04-01

    Lime or dolomite is commonly implemented to ameliorate soil acidity. However, the impact of dolomite on CO2 emissions from acidic soils is largely unknown. A 53-day laboratory study was carried out to investigate CO2 emissions by applying dolomite to an acidic Acrisol (rice-rapeseed rotation [RR soil]) and a Ferralsol (rice-fallow/flooded rotation [RF soil]). Dolomite was dosed at 0, 0.5, and 1.5 g 100 g-1 soil, herein referred to as CK, L, and H, respectively. The soil pH(H2O) increased from 5.25 to 7.03 and 7.62 in L and H treatments of the RR soil and from 5.52 to 7.27 and 7.77 in L and H treatments of the RF soil, respectively. Dolomite application significantly (p ≤ 0.001) increased CO2 emissions in both RR and RF soils, with higher emissions in H as compared to L dose of dolomite. The cumulative CO2 emissions with H dose of dolomite were greater 136% in the RR soil and 149% in the RF soil as compared to CK, respectively. Dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased and reached at 193 and 431 mg kg-1 in the RR soil and 244 and 481 mg kg-1 in the RF soil by H treatments. The NH4--N and NO3--N were also increased by dolomite application. The increase in C and N contents stimulated microbial activities and therefore higher respiration in dolomite-treated soil as compared to untreated. The results suggest that CO2 release in dolomite-treated soils was due to the priming of soil C content rather than chemical reactions.

  17. A one-step carbonization route towards nitrogen-doped porous carbon hollow spheres with ultrahigh nitrogen content for CO 2 adsorption

    KAUST Repository

    Wang, Yu

    2015-01-01

    © The Royal Society of Chemistry 2015. Nitrogen doped porous carbon hollow spheres (N-PCHSs) with an ultrahigh nitrogen content of 15.9 wt% and a high surface area of 775 m2 g-1 were prepared using Melamine-formaldehyde nanospheres as hard templates and nitrogen sources. The N-PCHSs were completely characterized and were found to exhibit considerable CO2 adsorption performance (4.42 mmol g-1).

  18. High-surface-area carbon molecular sieves for selective CO(2) adsorption.

    Science.gov (United States)

    Wahby, Anass; Ramos-Fernández, José M; Martínez-Escandell, Manuel; Sepúlveda-Escribano, Antonio; Silvestre-Albero, Joaquín; Rodríguez-Reinoso, Francisco

    2010-08-23

    A series of carbon molecular sieves (CMSs) has been prepared, either as powders or monoliths, from petroleum pitch using potassium hydroxide as the activating agent. The CMS monoliths are prepared without the use of a binder based on the self-sintering ability of the mesophase pitch. Characterization results show that these CMSs combine a large apparent surface area (up to ca. 3100 m(2) g(-1)) together with a well-developed narrow microporosity (V(n) up to ca. 1.4 cm(3) g(-1)). The materials exhibit high adsorption capacities for CO(2) at 1 bar and 273 K (up to ca. 380 mg CO(2) g sorbent(-1)). To our knowledge, this is the best result obtained for CO(2) adsorption using carbon-based materials. Furthermore, although the CO(2) adsorption capacity for activated carbons has usually been considered lower than that of zeolites, the reported values exceed the total amount adsorbed on traditional 13X and 5A zeolites (ca. 230 mg and 180 mg CO(2) g sorbent(-1), respectively), under identical experimental conditions. Additionally, the narrow pore openings found in the CMS samples (ca. 0.4 nm) allows for the selective adsorption of CO(2) from molecules of similar dimensions (e.g., CH(4) and N(2)).

  19. High-resolution emissions of CO2 from power generation in the USA

    Science.gov (United States)

    PéTron, Garielle; Tans, Pieter; Frost, Gregory; Chao, Danlei; Trainer, Michael

    2008-12-01

    Electricity generation accounts for close to 40% of the U.S. CO2 emissions from fossil fuel burning, making it the economic sector with the largest source of CO2. Since the late 1990s, the Environmental Protection Agency Clean Air Markets Division (EPA CAMD) has kept a repository of hourly CO2 emission data for most power plants in the conterminous United States. In this study, the CAMD CO2 data are used to derive a high spatiotemporal resolution CO2 emissions inventory for the electricity generation sector (inventory available on request). Data from 1998 to 2006 have been processed. This unique inventory can be used to improve the understanding of the carbon cycle at fine temporal and spatial scales. The CAMD data set provides the first quantitative estimates of the diurnal and seasonal cycles of the emissions as well as the year to year variability. Emissions peak in the summertime owing to the widespread use of air conditioning. Summertime emissions are in fact highly correlated with the daily average temperature. In conjunction with the EPA Emissions and Generation Resource Integrated Database (eGRID), we have derived high-resolution maps of CO2 emissions by fossil fuel burned (coal, gas, oil) for the year 2004. The CAMD data set also reflects regional anomalies in power generation such as the August 2003 blackout in the northeastern United States and the 2000-2001 increase in production in California. We recommend that all sectors of the economy report similar high-resolution CO2 emissions because of their great usefulness both for carbon cycle science and for greenhouse gases emissions mitigation and regulation.

  20. Biological and physical influences on the carbon isotope content of CO2 in a subalpine forest snowpack, Niwot Ridge, Colorado

    Science.gov (United States)

    D. R. Bowling; W. J. Massman; S. M. Schaeffer; S. P. Burns; R. K. Monson; M. W. Williams

    2009-01-01

    Considerable research has recently been devoted to understanding biogeochemical processes under winter snow cover, leading to enhanced appreciation of the importance of many winter ecological processes. In this study, a comprehensive investigation of the stable carbon isotope composition (δ 13C) of CO2 within a high-elevation subalpine...

  1. 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.

  2. Effect of free Cr content on corrosion behavior of 3Cr steels in a CO2 environment

    Science.gov (United States)

    Li, Wei; Xu, Lining; Qiao, Lijie; Li, Jinxu

    2017-12-01

    The corrosion behavior of 3Cr steels with three microstructures (martensite, bainite, combined ferrite and pearlite) in simulated oil field formation water with a CO2 partial pressure of 0.8 MPa was investigated. The relationships between Cr concentrations in corrosion scales and corrosion rates were studied. The precipitated phases that contained Cr were observed in steels of different microstructures, and free Cr content levels were compared. The results showed that steel with the martensite microstructure had the highest free Cr content, and thus had the highest corrosion resistance. The free Cr content of bainite steel was lower than that of martensite steel, and the corrosion rate of bainite steel was higher than that of martensite steel. Because large masses of Cr were combined in ferrite and pearlite steel, the corrosion rates of ferrite and pearlite steel were the highest. Free Cr content in steel affects its corrosion behavior greatly.

  3. 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.

  4. Selective Metal-Free Hydrosilylation of CO2 Catalyzed by Triphenylborane in Highly Polar, Aprotic Solvents.

    Science.gov (United States)

    Mukherjee, Debabrata; Sauer, Daniel F; Zanardi, Alessandro; Okuda, Jun

    2016-06-01

    Triphenylborane (BPh3 ) in highly polar, aprotic solvents catalyzes hydrosilylation of CO2 effectively under mild conditions to provide silyl formates with high chemoselectivity (>95 %) and without over-reduction. This system also promotes reductive hydrosilylation of tertiary amides as well as dehydrogenative coupling of silane with alcohols. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Aesthetic skin resurfacing with the high-energy ultrapulsed CO2 laser.

    Science.gov (United States)

    Weinstein, C; Roberts, T L

    1997-04-01

    CO2 laser resurfacing, using the new generation high-energy output pulsed lasers, provides a highly accurate method of resurfacing and rejuvenating facial skin. Its applications are widespread and well accepted by the general population (Color Figs. 3 to 8). Complications may occur, which may be minimized through adequate laser training and appreciation of the mechanisms of skin healing.

  6. A reagent-free SIA module for monitoring of sugar, color and dissolved CO2 content in soft drinks.

    Science.gov (United States)

    Teerasong, S; Chan-Eam, S; Sereenonchai, K; Amornthammarong, N; Ratanawimarnwong, N; Nacapricha, D

    2010-05-23

    This work presents a new sequential injection analysis (SIA) method and a module for simultaneous and real-time monitoring of three key parameters for the beverage industry, i.e., the sugar content (measured in Brix), color and dissolved CO(2). Detection of the light reflection at the liquid interface (the schlieren effect) of sucrose and water was utilized for sucrose content measurement. A near infrared LED (890+/-40 nm) was chosen as the light source to ensure that all the ingredients and dyes in soft drinks will not interfere by contributing light absorption. A linear calibration was obtained for sucrose over a wide concentration range (3.1-46.5 Brix). The same module can be used to monitor the color of the soft drink as well as the dissolved CO(2) during production. For measuring the color, the sample is segmented between air plugs to avoid dispersion. An RGB-LED was chosen as the light source in order to make this module applicable to a wide range of colored samples. The module also has a section where dissolved CO(2) is measured via vaporization of the gas from the liquid phase. Dissolved CO(2), in a flowing acceptor stream of water resulting in the change of the acceptor conductivity, is detected using an in-house capacitively coupled contactless conductivity detector (C(4)D). The module includes a vaporization unit that is also used to degas the carbonated drink, prior the measurements of sucrose and color within the same system. The method requires no chemicals and is therefore completely friendly to the environment. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Gravity Wave-induced High-altitude CO2 Ice Clouds in Mars' Atmosphere

    Science.gov (United States)

    Yigit, E.; Medvedev, A. S.; Hartogh, P.

    2015-12-01

    First general circulation model simulations that quantify and reproduce patches of cold air required for CO2 condensation and ice cloud formation in Mars' atmosphere are presented. Results suggest that these ice clouds are generated by lower atmospheric small-scale gravity waves (GWs) accounted for in the model with the interactively implemented spectral GW parameterization of Yiğit et al. (2008). Distributions of GW-induced temperature fluctuations and occurrences of supersaturation conditions are in a good qualitative agreement with observations of high-altitude CO2 ice clouds. Our study confirms the key role of subgrid-scale GWs in facilitating high-altitude CO2 cloud formation and predicts clouds at altitudes higher than have been observed to date.

  8. Transport properties of high-performance all-Heusler Co2CrSi/Cu2CrAl/Co2CrSi giant magnetoresistance device

    Science.gov (United States)

    Bai, Z. Q.; Lu, Y. H.; Shen, L.; Ko, V.; Han, G. C.; Feng, Y. P.

    2012-05-01

    Transport properties of giant magnetoresistance (MR) junction consisting of trilayer Co2CrSi/Cu2CrAl/Co2CrSi Heusler alloys (L21) are studied using first-principles approach based on density functional theory and the non-equilibrium Green's function method. Highly conductive channels are found in almost the entire k-plane when the magnetizations of the electrodes are parallel, while they are completely blocked in the antiparallel configuration, which leads to a high magnetoresistance ratio (the pessimistic MR ratio is nearly 100%). Furthermore, the calculated I-V curve shows that the device behaves as a good spin valve with a considerable disparity in currents under the parallel and antiparallel magnetic configurations of the electrodes. The Co2CrSi/Cu2CrAl/Co2CrSi junction could be useful for high-performance all-metallic current-perpendicular-to-plane giant magnetoresistance reading head for the next generation high density magnetic storage.

  9.  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...

  10. High resolution infrared spectroscopy of carbon dioxide clusters up to (CO2)13.

    Science.gov (United States)

    Norooz Oliaee, J; Dehghany, M; McKellar, A R W; Moazzen-Ahmadi, N

    2011-07-28

    Thirteen specific infrared bands in the 2350 cm(-1) region are assigned to carbon dioxide clusters, (CO(2))(N), with N = 6, 7, 9, 10, 11, 12 and 13. The spectra are observed in direct absorption using a tuneable infrared laser to probe a pulsed supersonic jet expansion of a dilute mixture of CO(2) in He carrier gas. Assignments are aided by cluster structure calculations made using two reliable CO(2) intermolecular potential functions. For (CO(2))(6), two highly symmetric isomers are observed, one with S(6) symmetry (probably the more stable form), and the other with S(4) symmetry. (CO(2))(13) is also symmetric (S(6)), but the remaining clusters are asymmetric tops with no symmetry elements. The observed rotational constants tend to be slightly (≈2%) smaller than those from the predicted structures. The bands have increasing vibrational blueshifts with increasing cluster size, similar to those predicted by the resonant dipole-dipole interaction model but significantly larger in magnitude. © 2011 American Institute of Physics

  11. High quality electron bunch generation with CO2-laser-plasma interaction

    Science.gov (United States)

    Zhang, Lingang; Shen, Baifei; Xu, Jiancai; Ji, Liangliang; Zhang, Xiaomei; Wang, Wenpeng; Zhao, Xueyan; Yi, Longqing; Yu, Yahong; Shi, Yin; Xu, Tongjun; Xu, Zhizhan

    2015-02-01

    CO2 laser-driven electron acceleration in low-density plasma is demonstrated using particle-in-cell simulation. An intense CO2 laser pulse of long wavelength excites a wake bubble that has a large elongated volume for accelerating a large number of electrons before reaching the charge saturation limit. A transversely injected laser pulse is used to induce and control the electron injection. It is found that an electron bunch with total charge up to 10 nC and absolute energy spread less than 16 MeV can be obtained. As a result, the charge per energy interval of the bunch reaches up to 0.6 nC/MeV. Intense CO2-laser based electron acceleration can provide a new direction for generating highly charged electron bunches with low energy spread, which is of much current interest, especially for table-top X-ray generation.

  12. High quality electron bunch generation with CO2-laser plasma accelerator

    CERN Document Server

    Zhang, L G; Xu, J C; Ji, L L; Zhang, X M; Wang, W P; Zhao, X Y; Yi, L Q; Yu, Y H; Shi, Y; Xu, T J; Xu, Z Z

    2014-01-01

    CO2 laser-driven electron acceleration is demonstrated with particle-in-cell simulation in low-density plasma. An intense CO2 laser pulse with long wavelength excites wakefield. The bubble behind it has a broad space to sustain a large amount of electrons before reaching its charge saturation limit. A transversely propagating inject pulse is used to induce and control the ambient electron injection. The accelerated electron bunch with total charge up to 10 nC and the average charge per energy interval of more than 0.6 nC/MeV are obtained. Plasma-based electron acceleration driven by intense CO2 laser provides a new potential way to generate high-charge electron bunch with low energy spread, which has broad applications, especially for X-ray generation by table-top FEL and bremsstrahlung.

  13. 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

    Imaging nanoparticles under relevant reaction conditions of high temperature and gas pressure is difficult because conventional imaging techniques, like transmission electron microscopy, cannot be used. Here we demonstrate that the coherent diffractive imaging technique of X-ray ptychography can...... 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...

  14. Fluorous Metal-Organic Frameworks with Enhanced Stability and High H2/CO2 Storage Capacities

    Science.gov (United States)

    Zhang, Da-Shuai; Chang, Ze; Li, Yi-Fan; Jiang, Zhong-Yi; Xuan, Zhi-Hong; Zhang, Ying-Hui; Li, Jian-Rong; Chen, Qiang; Hu, Tong-Liang; Bu, Xian-He

    2013-01-01

    A new class of metal-organic frameworks (MOFs) has been synthesized by ligand-functionalization strategy. Systematic studies of their adsorption properties were performed at low and high pressure. Importantly, when fluorine was introduced into the framework via the functionalization, both the framework stabilities and adsorption capacities towards H2/CO2 were enhanced significantly. This consequence can be well interpreted by theoretical studies of these MOFs structures. In addition, one of these MOFs TKL-107 was used to fabricate mixed matrix membranes, which exhibit great potential for the application of CO2 separation. PMID:24264725

  15. 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

    in terms of a detailed chemical kinetic mechanism for hydrocarbon oxidation. On the basis of results of the present study, it can be expected that oxy-fuel combustion will lead to strongly increased CO concentrations in the near-burner region. The CO2 present will compete with O-2 for atomic hydrogen...... 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....

  16. 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.

  17. 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.

  18. High-temperature argon broadening of CO2 near 2190 cm-1 in a shock tube

    Science.gov (United States)

    Mulvihill, C. R.; Petersen, E. L.

    2017-10-01

    Scanned-wavelength laser absorption measurements of CO2 diluted in Ar were performed behind reflected shock waves at high temperatures (1158-2017 K) and low pressures (5.1-108.4 kPa). High-resolution (0.001 cm-1) scans were conducted in 0.4-cm-1 increments from about 2188.8 to 2191.8 cm-1 at a scan rate of 2 kHz. The HITRAN 2004, HITRAN 2012, and CDSD-296 databases were all found to underestimate the absorption, typically by an order of magnitude or more. The HITEMP database, however, closely predicted the measured data. For the assumed form γ_{{{CO}_{ 2} - {Ar}}} (T) = γ_{{{CO}_{ 2} - {Ar}}} (T0 )(T0 /T)n with T0 = 296 K, an optimization routine was implemented to determine the values of γ_{{{CO}_{ 2} - {Ar}}} (T0 ) and n. From the optimization, values of 0.033 ± 0.004 cm-1 atm.-1 and 0.61 ± 0.04 were determined for γ_{{{CO}_{ 2} - {Ar}}} (T0 ) and n, respectively, which are in good agreement with historical values. These values describe an average CO2-Ar broadening coefficient in the frequency range studied herein and are reliable within the experimental temperature range. In addition, a set of fixed-wavelength measurements at 2190.0175 cm-1 were carried out at 122, 446, and 1115 kPa between 1100 and 2100 K, and the HITEMP predictions incorporating the proposed Ar-broadening parameters showed excellent agreement with these data.

  19. 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 CO2 environments are more resilient compared with those molluscs naive to CO2 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-CO2 world; either high-shore oysters will be more tolerant of elevated PCO2 because of their regular acidosis, or elevated PCO2  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 PCO2 , and physiological variables were measured. The combined treatment of tidal emersion and elevated PCO2  interacted synergistically to reduce the haemolymph pH (pHe) of oysters, and increase the PCO2  in the haemolymph (Pe,CO2 ) 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-CO2 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 PCO2. © 2017. Published by The Company of Biologists Ltd.

  20. Tetrahedral tetrazolate frameworks for high CO2 and H2 uptake.

    Science.gov (United States)

    Wang, Fei; Hou, Duan-Chuan; Yang, Hui; Kang, Yao; Zhang, Jian

    2014-02-28

    Three tetrahedral tetrazolate frameworks with two different 4-connected topologies including lonsdaleite (lon, for 1) and diamond (dia, for 2 and 3) have been synthesized, and the lon-type framework with high CO2 and H2 uptake capacity can irreversibly transform to the dia-type framework via solvent-exchange.

  1. 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.

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

    Indian Academy of Sciences (India)

    A DC excited waveguide multibeam CO2 laser is reported having six glass discharge tubes. Simultaneous excitation of DC discharge in all sections is achieved by producing pre-ionization using an auxiliary high frequency pulsed discharge along with its other advantages. Maximum 170 W output power is obtained with all ...

  3. [Treatment of giant congenital nevus with high-energy pulsed CO2 laser].

    Science.gov (United States)

    Michel, J L; Caillet-Chomel, L

    2001-11-01

    All authors agree upon the need for early treatment of giant congenital nevi. The surgeon must seek to minimize the risk of malignancy. The objective calls for radical excision of all pigmented areas; this may be impossible because of the risk of leaving the patient with disfiguring scars. The aim of this study was to assess treatment of giant congenital nevi with the high-energy pulsed CO2 laser as an alternative to surgery. Between 1998 and 1999, the high-energy pulsed CO2 laser was used in nine newborns and five children. The treatment with the high-energy pulsed CO2 laser achieved 70-90% clearing of the giant nevi in most of the children. Two children developed hypertrophic scars on a companion nevi and on giant congenital nevi. One child required a skin graft because of tissue necrosis, associated with a disseminated intravascular coagulation and septic shock. Laser is a surface technique proposed when surgical excision cannot be performed because the surface is too large or the localization is incompatible with surgery. Early treatment, in the first 15 days, is not required for the quality of the cosmetic result. The high-energy pulsed CO2 laser provides satisfactory cosmetic results with short cicatrisation time. It allows the treatment of the companion nevi at the same time. The risk of malignant transformation is greatly but not totally reduced. Regular clinical surveillance should help reduce the risk.

  4. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  5. Highly Dense Cu Nanowires for Low-Overpotential CO2 Reduction.

    Science.gov (United States)

    Raciti, David; Livi, Kenneth J; Wang, Chao

    2015-10-14

    Electrochemical reduction of CO2, an artificial way of carbon recycling, represents one promising solution for energy and environmental sustainability. However, it is challenged by the lack of active and selective catalysts. Here, we report a two-step synthesis of highly dense Cu nanowires as advanced electrocatalysts for CO2 reduction. CuO nanowires were first grown by oxidation of Cu mesh in air and then reduced by either annealing in the presence of hydrogen or applying a cathodic electrochemical potential to produce Cu nanowires. The two reduction methods generated Cu nanowires with similar dimensions but distinct surface structures, which have provided an ideal platform for comparative studies of the effect of surface structure on the electrocatalytic properties. In particular, the Cu nanowires generated by electrochemical reduction were highly active and selective for CO2 reduction, requiring an overpotential of only 0.3 V to reach 1 mA/cm(2) electrode current density and achieving Faradaic efficiency toward CO as high as ∼60%. Our work has advanced the understanding of the structure-property relationship of Cu-based nanocatalysts, which could be valuable for the further development of advanced electrocatalytic materials for CO2 reduction.

  6. Ultrathin Bismuth nanosheets as highly efficient electrocatalyst for CO2 reduction.

    Science.gov (United States)

    Su, Panpan; Xu, Wenbin; Qiu, Yanling; Zhang, Taotao; Li, Xianfeng; Zhang, Huamin

    2018-01-11

    Electrochemical reducing CO2 to value-added products is an important and challenging reaction for sustainable energy study. In this study, bismuth nanosheets with thickness of ~10 nm were successfully prepared via electrochemical reduction of Bi3+. Ultrathin Bi nanosheets with numerous low-coordination sites can efficiently reduce CO2 to formate in aqueous solution. During the potential range of - 0.9 V to - 1.2 V vs RHE, the faradaic efficiency of formate is over 90%, which is one of the best reported Bi catalysts. At -0.7 V, the prepared Bi nanosheets exhibit much higher current for formate generation than that of bulk Bi, which is due to not only high surface area but also intrinsic electronic property change of ultrathin structure. Further, DFT calculation demonstrates that Bi nanosheets have the much higher electron state density around Fermi level than bulk counterpart, which favors the improvement of CO2 reduction on Bi nanosheets. At -1.0 V, Bi nanosheets exhibit high selectivity for formate and excellent stability during 5 hrs electrolysis measurement. The prepared Bi nanosheets with high activity and superior stability show great potential toward CO2 reduction area. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Altered Carbon Isotope Discrimination of C3 Plants Under Very High pCO2 Levels

    Science.gov (United States)

    Panetta, R. J.; Schubert, B.; Jahren, H.

    2009-12-01

    Various modeling and proxy-based reconstructions of atmospheric pCO2 levels for the last 120 Ma have estimated RCO2 as high as 12x for the Early Cretaceous, generally decreasing into the Cenozoic, and decreasing further into the Quaternary. Multiple ecological studies to assess the effect of elevated CO2 on plant biomass and δ13C value have been spurred on by recent increases in greenhouse gases, however these studies typically grow plants under only slightly elevated CO2 levels (i.e., the twenty foremost studies published since 1990 involved 550 to 750 ppm pCO2, which equals RCO2 = 1.4 to 1.9x). In order to recreate the highest pCO2 environments of the last 120 Ma, we grew radish (Raphanus sativus L.) in growth chambers that maintained controlled environmental conditions and pCO2 levels ranging from ~5 to 11x that of today’s atmosphere (1791 to 4200 ppm); upon harvest we measured total biomass and stable carbon isotope ratio (δ13Cplant) in both above and below ground plant tissue. Unlike the 1:1 relationship between stable isotopes of atmospheric CO2 (δ13Catm) and δ13Cplant observed at lower pCO2 levels (i.e., RCO2 = 1x to 3x; Jahren et al., 2008), the δ13Cplant of biomass grown at more elevated RCO2 was dependent upon δ13Catm according to the linear relationship: δ13Cplant = 1.9(δ13Cplant) - 12.2 ‰ (r2 = 0.71). Concomitantly, we see a highly significant (p sativus L. from -27.0 to -28.0 ‰ at RCO2 = 5x to 11x, respectively. We will discuss possible mechanisms for changing isotope discrimination at very high pCO2 levels that may not be operative at lower concentrations. For example, we noted a striking reduction in the variability of biomass between plants grown at the same (very high) level of pCO2. This variability (calculated as the standard deviation of the log-transformed biomass data after Poorter and Garnier, 1996) decreased by 37 % (above-ground) and 48 % (below-ground) for plants grown at RCO2 > 5x compared to plants grown at RCO2 = 1x to 3x

  8. 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.

  9. 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.

  10. Advanced concepts for high-power, short-pulse CO2 laser development

    Science.gov (United States)

    Gordon, Daniel F.; Hasson, Victor; von Bergmann, Hubertus; Chen, Yu-hsin; Schmitt-Sody, A.; Penano, Joseph R.

    2016-06-01

    Ultra-short pulse lasers are dominated by solid-state technology, which typically operates in the near-infrared. Efforts to extend this technology to longer wavelengths are meeting with some success, but the trend remains that longer wavelengths correlate with greatly reduced power. The carbon dioxide (CO2) laser is capable of delivering high energy, 10 micron wavelength pulses, but the gain structure makes operating in the ultra-short pulse regime difficult. The Naval Research Laboratory and Air Force Research Laboratory are developing a novel CO2 laser designed to deliver ~1 Joule, ~1 picosecond pulses, from a compact gain volume (~2x2x80 cm). The design is based on injection seeding an unstable resonator, in order to achieve high energy extraction efficiency, and to take advantage of power broadening. The unstable resonator is seeded by a solid state front end, pumped by a custom built titanium sapphire laser matched to the CO2 laser bandwidth. In order to access a broader range of mid infrared wavelengths using CO2 lasers, one must consider nonlinear frequency multiplication, which is non-trivial due to the bandwidth of the 10 micron radiation.

  11. 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.

  12. Relation between Cutting Surface Quality and Alloying Element Contents when Using a CO2 Laser

    Directory of Open Access Journals (Sweden)

    J. Litecká

    2011-01-01

    Full Text Available This paper deals with the influence of material content on changes in the quality parameters of the cutting surface when cutting with a laser. The study focuses on experiments to find the effect of material structure and cutting parameters on surface roughness, Vickers microhardness and precision of laser cutting. The experimental results are shown in graphs which illustrate the suitability of materials for achieving required cutting surface quality parameters. These results can be used for optimizing production in practical applications using a laser cutting machine.

  13. 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.

  14. 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.

  15. A new high precision 14CO2 time series for North American continental air

    Science.gov (United States)

    Turnbull, Jocelyn C.; Lehman, Scott J.; Miller, John B.; Sparks, Rodger J.; Southon, John R.; Tans, Pieter P.

    2007-06-01

    We develop a high precision Δ14CO2 measurement capability in 2-5 L samples of whole air for implementation within existing greenhouse gas flask sampling networks. The long-term repeatability of the measurement is 1.8‰ (1-sigma), as determined from repeated analyses of quality control standards and replicate extraction and measurement of authentic field samples. In a parallel effort, we have begun a Δ14CO2 measurement series from NOAA/ESRL's (formerly NOAA/CMDL) surface flask sampling site at Niwot Ridge, Colorado, USA (40.05°N, 105.58°W, 3475 masl) in order to monitor the isotopic composition of carbon dioxide in relatively clean air over the North American continent. Δ14CO2 at Niwot Ridge decreased by 5.7‰/yr from 2004 to 2006, with a seasonal amplitude of 3-5‰. A comparison with measurements from the free troposphere above New England, USA (41°N, 72°W) indicates that the Δ14CO2 series at the two sites are statistically similar at timescales longer than a few days to weeks (i.e., those of synoptic scale variations in transport), suggesting that the Niwot Ridge measurements can be used as a proxy for North American free tropospheric air in future carbon cycle studies.

  16. High power CO2 coherent ladar haven't quit the stage of military affairs

    Science.gov (United States)

    Zhang, Heyong

    2015-05-01

    The invention of the laser in 1960 created the possibility of using a source of coherent light as a transmitter for a laser radar (ladar). Coherent ladar shares many of the basic features of more common microwave radars. However, it is the extremely short operating wavelength of lasers that introduces new military applications, especially in the area of missile identification, space target tracking, remote rang finding, camouflage discrimination and toxic agent detection. Therefore, the most popular application field such as laser imaging and ranging were focused on CO2 laser in the last few decades. But during the development of solid state and fiber laser, some people said that the CO2 laser will be disappeared and will be replaced by the solid and fiber laser in the field of military and industry. The coherent CO2 laser radar will have the same destiny in the field of military affairs. However, to my opinion, the high power CO2 laser will be the most important laser source for laser radar and countermeasure in the future.

  17. Varying response of the concentration and content of soybean seed mineral elements, carbohydrates, organic acids, amino acids, protein, and oil to phosphorus starvation and CO2 enrichment

    Science.gov (United States)

    A detailed investigation of the concentration (g-1 seed weight) and content (g plant-1) of seed mineral elements and metabolic profile under phosphorus (P) starvation at ambient (aCO2) and elevated carbon dioxide (eCO2) in soybean is limited. Soybean plants were grown in a controlled environment at ...

  18. 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.

  19. Development of tunable high pressure CO2 laser for lidar measurements of pollutants and wind velocities

    Science.gov (United States)

    Levine, J. S.; Guerra, M.; Javan, A.

    1980-01-01

    The problem of laser energy extraction at a tunable monochromatic frequency from an energetic high pressure CO2 pulsed laser plasma, for application to remote sensing of atmospheric pollutants by Differential Absorption Lidar (DIAL) and of wind velocities by Doppler Lidar, was investigated. The energy extraction principle analyzed is based on transient injection locking (TIL) at a tunable frequency. Several critical experiments for high gain power amplification by TIL are presented.

  20. 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.

  1. High-resolution mapping of combustion processes and implications for CO2 emissions

    Science.gov (United States)

    Wang, R.; Tao, S.; Ciais, P.; Shen, H. Z.; Huang, Y.; Chen, H.; Shen, G. F.; Wang, B.; Li, W.; Zhang, Y. Y.; Lu, Y.; Zhu, D.; Chen, Y. C.; Liu, X. P.; Wang, W. T.; Wang, X. L.; Liu, W. X.; Li, B. G.; Piao, S. L.

    2013-05-01

    High-resolution mapping of fuel combustion and CO2 emission provides valuable information for modeling pollutant transport, developing mitigation policy, and for inverse modeling of CO2 fluxes. Previous global emission maps included only few fuel types, and emissions were estimated on a grid by distributing national fuel data on an equal per capita basis, using population density maps. This process distorts the geographical distribution of emissions within countries. In this study, a sub-national disaggregation method (SDM) of fuel data is applied to establish a global 0.1° × 0.1° geo-referenced inventory of fuel combustion (PKU-FUEL) and corresponding CO2 emissions (PKU-CO2) based upon 64 fuel sub-types for the year 2007. Uncertainties of the emission maps are evaluated using a Monte Carlo method. It is estimated that CO2 emission from combustion sources including fossil fuel, biomass, and solid wastes in 2007 was 11.2 Pg C yr-1 (9.1 Pg C yr-1 and 13.3 Pg C yr-1 as 5th and 95th percentiles). Of this, emission from fossil fuel combustion is 7.83 Pg C yr-1, which is very close to the estimate of the International Energy Agency (7.87 Pg C yr-1). By replacing national data disaggregation with sub-national data in this study, the average 95th minus 5th percentile ranges of CO2 emission for all grid points can be reduced from 417 to 68.2 Mg km-2 yr-1. The spread is reduced because the uneven distribution of per capita fuel consumptions within countries is better taken into account by using sub-national fuel consumption data directly. Significant difference in per capita CO2 emissions between urban and rural areas was found in developing countries (2.08 vs. 0.598 Mg C/(cap. × yr)), but not in developed countries (3.55 vs. 3.41 Mg C/(cap. × yr)). This implies that rapid urbanization of developing countries is very likely to drive up their emissions in the future.

  2. Wettability characteristics of a modified mild steel with CO2, Nd:YAG, excimer and high power diode lasers

    OpenAIRE

    Lawrence, Jonathan; Li, Lin

    1999-01-01

    Interaction of CO2, Nd:YAG, excimer and high-power diode laser radiation with the surface of a common mild steel (EN8) was found to effect changes in the wettability characteristics of the steel, namely changes in the measured contact angle of certain liquids. Such changes were identified as being due to modifications to (i) the surface roughness, (ii) changes in the surface oxygen content and (iii) changes in the surface energy of the mild steel. However, it was found that changes in the wet...

  3. 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 C. E.; Pfeil, Benjamin; Landa, Camilla S.; Metzl, Nicolas; O'Brien, Kevin M.; Olsen, Are; Smith, Karl; Cosca, Cathy; Harasawa, Sumiko; Jones, Stephen D.; Nakaoka, Shin-ichiro; Nojiri, Yukihiro; Schuster, Ute; Steinhoff, Tobias; Sweeney, Colm; Takahashi, Taro; Tilbrook, Bronte; Wada, Chisato; Wanninkhof, Rik; Alin, Simone R.; Balestrini, Carlos F.; Barbero, Leticia; Bates, Nicholas R.; 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 A.; Fransson, Agneta; Goyet, Catherine; Greenwood, Naomi; Gregor, Luke; Hankin, Steven; 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; 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, Doug; Ward, Brian; Watson, Andrew J.; Xu, Suqing

    2016-09-01

    The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 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 fCO2 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 fCO2 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). Individual

  4. The ever-increasing CO2 seasonal cycle amplitude: contributions from high latitude warming, CO2 fertilization, and the agricultural Green Revolution

    Science.gov (United States)

    Zeng, N.; Martin, C.; Zhao, F.; Collatz, G. J.; Kalnay, E.; Salawitch, R. J.; West, T. O.; Guanter, L.

    2014-12-01

    Human activities has tranformed the Earth's surface in complex ways. Here we show that not only land cover change, but also the management intensity, namely the intensification of agriculture through the Green Revolution has had a profound impact on the carbon cycle. A long-standing puzzle in the global carbon cycle is the increase in the amplitude of the seasonal cycle of atmospheric CO2. This increase likely reflects enhanced biological activity in the Northern Hemisphere (NH). It has been hypothesized that vegetation growth may have been stimulated by higher concentrations of CO2 as well as warming in recent decades, but the role of such specific mechanisms has not been quantified and they have been unable to explain the full range and magnitude of observations. Here we suggest another potential driver of the increased seasonal amplitude: the intensification of agriculture from the Green Revolution to feed a rising population, that led to a 3-fold increase in world crop production over the last 5 decades. Our analysis of CO2 data and atmospheric inversions shows a robust 15% long-term increase in CO2 seasonal amplitude from 1961 to 2010 that is punctuated by large decadal and interannual variations. The three pillars of the Green Revolution, consisting of high yield cultivars, fertilizer use, and irrigation, are represented in a terrestrial carbon cycle model. The results reveal that the long-term increase in CO2 seasonal amplitude arises from two major regions in the NH: the mid-latitude cropland between 25N-60N that encompasses the world's major agriculture zones in Asia, Europe and North America, and the high-latitude natural vegetation between 50N-70N that includes much of the Northern boreal forests, tundra and some deciduous forests. The long-term trend of seasonal amplitude is 0.3% per year, of which sensitivity experiments attribute 43% to land use change, 31% to climate variability and change, and 26% to CO2 fertilization. Our results suggest that human

  5. 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.; Keeling, Ralph F.; Johannessen, Truls; 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). 

  6. Starch Content in Leaf Sheath Controlled by CO2-Responsive CCT Protein is a Potential Determinant of Photosynthetic Capacity in Rice.

    Science.gov (United States)

    Morita, Ryutaro; Inoue, Kanako; Ikeda, Ken-Ichi; Hatanaka, Tomoko; Misoo, Shuji; Fukayama, Hiroshi

    2016-11-01

    CO2-responsive CCT protein (CRCT) is the suggested positive regulator of starch synthesis in vegetative organs, particularly the leaf sheath of rice. In this study, we analyzed the effects of the starch level in the leaf sheath on the photosynthetic rate in the leaf blade using CRCT overexpression and RNA interference (RNAi) knockdown transgenic rice grown under ambient (38 Pa) or elevated (100 Pa) CO2 conditions. In leaf sheath, the starch content was markedly changed in relation to CRCT expression levels under both CO2 conditions. In contrast, the soluble sugar and starch contents of the leaf blade were markedly increased in the knockdown line grown under elevated CO2 conditions. The overexpression or RNAi knockdown of CRCT did not cause large effects on the photosynthetic rate of the transgenic lines grown under ambient CO2 condition. However, the photosynthetic rate of the overexpression line was enhanced, while that of the knockdown line was substantially decreased under elevated CO2 conditions. These photosynthetic rates were weakly correlated with the nitrogen contents and negatively correlated with the total non-structural carbohydrate contents. Thus, the capacity for starch synthesis in leaf sheath, which is controlled by CRCT, can indirectly affect the carbohydrate content, and then the photosynthetic rate in the leaf blade of rice grown under elevated CO2 conditions. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. Mathematical model for CO2 laser high precision ablation of fused silica

    Science.gov (United States)

    He, Ting; Shao, Jianda; Wei, Chaoyang; Jiang, Zhigang; Zhao, Jiaoling

    2017-08-01

    Optics manufactured by mechanical grinding and polishing inevitably will bring surface/subsurface damages and defects during the machining process. Laser polishing has been demonstrated as a technique capable of achieving ultra-smooth surface with no damage and low-defects, but by far optics polished by this technology are only sufficient for illumination applications. To achieve high quality optics, high precision laser ablation has been proved to be a promising technology for shape correction. With pulsed CO2 laser, high precision laser ablation can be performed by direct evaporation of unwanted surface asperities. To acquire nanometer scale high precision ablation, an accurate control and meticulous adjustment of temperature should be needed. Herein, a mathematical model has been established to assist the understanding of the thermal mechanism of CO2 laser ablation and subsequently a series of simulations have been extended to investigate the phase change of evaporation. The temperature of fused silica irradiated by CO2 laser can be controlled via laser power and pulse duration. To achieve nanometer ablation depth, a gentle evaporation regime at low laser intensity is necessary. The results indicated that the ablation depth linearly depend on laser fluence and depth control levels of nanometer are obtainable with the control of laser fluence.

  8. 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.

  9. Enhancement of CO2 capture in limestone and dolomite granular beds by high intensity sound waves

    Directory of Open Access Journals (Sweden)

    Valverde Jose Manuel

    2017-01-01

    Full Text Available The calcium looping (CaL process, based on the calcination/carbonation of CaCO3 at high temperatures, has emerged in the last years as a potentially low cost technology for CO2 capture. In this work, we show that the application of high intensity sound waves to granular beds of limestone and dolomite in a CaL reactor enhances significantly their multicycle CO2 capture capacity. Sound waves are applied either during the calcination stage of each CaL cycle or in the carbonation stage. The effect of sound is to intensify the transfer of heat, mass and momentum and is more marked when sound is applied during calcination by promoting CaO regeneration. The application of sound would allow reducing the calcination temperature thereby mitigating the decay of capture capacity with the number of cycles and reducing the energy penalty of the technology.

  10. Enhancement of CO2 capture in limestone and dolomite granular beds by high intensity sound waves

    Science.gov (United States)

    Valverde, Jose Manuel; Perez-Ebri, Jose Manuel; Sanchez-Quintanilla, Miguel Angel

    2017-06-01

    The calcium looping (CaL) process, based on the calcination/carbonation of CaCO3 at high temperatures, has emerged in the last years as a potentially low cost technology for CO2 capture. In this work, we show that the application of high intensity sound waves to granular beds of limestone and dolomite in a CaL reactor enhances significantly their multicycle CO2 capture capacity. Sound waves are applied either during the calcination stage of each CaL cycle or in the carbonation stage. The effect of sound is to intensify the transfer of heat, mass and momentum and is more marked when sound is applied during calcination by promoting CaO regeneration. The application of sound would allow reducing the calcination temperature thereby mitigating the decay of capture capacity with the number of cycles and reducing the energy penalty of the technology.

  11. High energy optical parametric source for multi-wavelength CO2 dial

    Science.gov (United States)

    Barrientos-Barria, Jessica; Dherbecourt, Jean-Baptiste; Raybaut, Myriam; Godard, Antoine; Melkonian, Jean-Michel; Lefebvre, Michel

    2017-11-01

    In the scope of the preparation of spaceborne lidar missions to measure the concentration of greenhouse gases with differential absorption LIDAR techniques, we report on the development of a high energy 2.05 μm optical parametric source based on a versatile architecture enabling multiple wavelengths generation in the vicinity of the R30 absorption line of CO2. The multi-wavelength configuration is under study for a few greenhouse gas active detection missions, such as Ascend.

  12. Collisionless dissociation and isotopic enrichment of SF6 using high-powered CO2 laser radiation

    Science.gov (United States)

    Gower, M. C.; Billman, K. W.

    1977-01-01

    Dissociation of S-32F6 and the resultant isotopic enrichment of S-34F6 using high-powered CO2 laser radiation has been studied with higher experimental sensitivity than previously reported. Enrichment factors have been measured as a function of laser pulse number, wavelength, energy and time duration. A geometry independent dissociation cross section is introduced and measured values are presented. Threshold energy densities, below which no dissociation was observed, were also determined.

  13. High power pulsed fiber laser development for Co2 space based dial system

    Science.gov (United States)

    Canat, Guillaume; Le Gouët, Julien; Lombard, Laurent; Bresson, Alexandre; Goular, Didier; Dolfi-Bouteyre, Agnès.; Duzellier, Sophie; Boivin, Denis; Nilsson, Johan; Sahu, Jayata; Bordais, Sylvain

    2017-11-01

    High energy fiber lasers emitting around 1579nm is seen as a possible technology for the laser unit of a spaceborn CO2 DIAL system. We are developing an all fiber system with the following expected performances: pulse energy of 260μJ, pulse duration 150ns, beam quality M2 laser stability 200 kHz. One of our main concerns has been the radiation induced attenuation mitigation. Various fiber compositions have been investigated.

  14. CO2 laser scribe of chemically strengthened glass with high surface compressive stress

    Science.gov (United States)

    Li, Xinghua; Vaddi, Butchi R.

    2011-03-01

    Chemically strengthened glass is finding increasing use in handheld, IT and TV cover glass applications. Chemically strengthened glass, particularly with high (>600MPa) compressive stress (CS) and deeper depth of layer (DOL), enable to retain higher strength after damage than non-strengthened glass when its surface is abraded. Corning Gorilla® Glass has particularly proven to be advantageous over competition in this attribute. However, due to high compressive stress (CS) and Central Tension (CT) cutting ion-exchanged glass is extremely difficult and often unmanageable where ever the applications require dicing the chemically strengthened mother glass into smaller parts. We at Corning have developed a CO2 laser scribe and break method (LSB) to separate a single chemically strengthened glass sheet into plurality of devices. Furthermore, CO2 laser scribe and break method enables debris-free separation of glass with high edge strength due to its mirror-like edge finish. We have investigated laser scribe and break of chemically strengthened glass with surface compressive stress greater than 600 MPa. In this paper we present the results of CO2 scribe and break method and underlying laser scribing mechanisms. We demonstrated cross-scribe repetitively on GEN 2 size chemically strengthened glass substrates. Specimens for edge strength measurements of different thickness and CS/DOL glass were prepared using the laser scribe and break technique. The specimens were tested using the standard 4-point bend method and the results are presented.

  15. Achieving Highly Efficient, Selective, and Stable CO2 Reduction on Nitrogen-Doped Carbon Nanotubes.

    Science.gov (United States)

    Wu, Jingjie; Yadav, Ram Manohar; Liu, Mingjie; Sharma, Pranav P; Tiwary, Chandra Sekhar; Ma, Lulu; Zou, Xiaolong; Zhou, Xiao-Dong; Yakobson, Boris I; Lou, Jun; Ajayan, Pulickel M

    2015-05-26

    The challenge in the electrosynthesis of fuels from CO2 is to achieve durable and active performance with cost-effective catalysts. Here, we report that carbon nanotubes (CNTs), doped with nitrogen to form resident electron-rich defects, can act as highly efficient and, more importantly, stable catalysts for the conversion of CO2 to CO. The unprecedented overpotential (-0.18 V) and selectivity (80%) observed on nitrogen-doped CNTs (NCNTs) are attributed to their unique features to facilitate the reaction, including (i) high electrical conductivity, (ii) preferable catalytic sites (pyridinic N defects), and (iii) low free energy for CO2 activation and high barrier for hydrogen evolution. Indeed, DFT calculations show a low free energy barrier for the potential-limiting step to form key intermediate COOH as well as strong binding energy of adsorbed COOH and weak binding energy for the adsorbed CO. The highest selective site toward CO production is pyridinic N, and the NCNT-based electrodes exhibit no degradation over 10 h of continuous operation, suggesting the structural stability of the electrode.

  16. Vanadium Oxide Supported on MSU-1 as a Highly Active Catalyst for Dehydrogenation of Isobutane with CO2

    Directory of Open Access Journals (Sweden)

    Guosong Sun

    2016-03-01

    Full Text Available Vanadium oxide supported on MSU-1, with VOx loading ranging from 2.5 to 17.5 wt. %, was developed as a highly active catalyst in dehydrogenation of isobutane with CO2. The obtained catalysts of VOx/MSU-1 were characterized by X-ray diffraction (XRD, N2 adsorption-desorption, and H2-temperature programmed reduction (H2-TPR methods and the results showed that the large surface area of MSU-1 was favorable for the dispersion of VOx species and the optimal loading of VOx was 12.0 wt. %. Meanwhile, the catalytic activity of VOx/MSU-1 was investigated, and VOx/MSU-1 with 12.0 wt. % VOx content was found to be the best one, with the conversion of isobutane (58.8% and the selectivity of isobutene (78.5% under the optimal reaction conditions. In contrast with the reaction in the absence of CO2, the presence of CO2 in the reaction stream could obviously enhance the isobutane dehydrogenation, which raised the conversion of reaction and the stability of VOx/MSU-1.

  17. 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.

  18. Phase Behavior at High Pressure of the Ternary System: CO2, Ionic Liquid and Disperse Dye

    Directory of Open Access Journals (Sweden)

    Helen R. Mazzer

    2012-01-01

    Full Text Available High pressure phase behavior experimental data have been measured for the systems carbon dioxide (CO2 + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6] and carbon dioxide (CO2 + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6] + 1-amino-2-phenoxy-4-hydroxyanthraquinone (C.I. Disperse Red 60. Measurements were performed in the pressure up to 18 MPa and at the temperature (323 to 353 K. As reported in the literature, at higher concentrations of carbon dioxide the phase transition pressure increased very steeply. The experimental data for the binary and ternary systems were correlated with good agreement using the Peng-Robinson equation of state. The amount of water in phase behavior of the systems was evaluated.

  19. Effects of high-pressure CO2 processing on flavor, texture, and color of foods.

    Science.gov (United States)

    Zhou, Linyan; Bi, Xiufang; Xu, Zenghui; Yang, Yingjie; Liao, Xiaojun

    2015-01-01

    High-pressure CO2 (HPCD) is a pasteurization method that inactivates microorganism and enzymes through molecular effects of CO2 under pressures below 50 MPa without exposing foods to adverse effects of heat. Thermal pasteurization can impart undesirable changes on organoleptic and nutritional quality of the foods, which can reduce sensory perception and consumer acceptance of the foods. As a novel nonthermal processing technique, HPCD does avoid drawbacks such as loss of flavor, denaturation of nutrients, production of side toxic reactions, as well as changes in physical, mechanical, and optical properties of the food materials involved in the processing. This review gives a survey and analysis of recent publications regarding the effects of HPCD on the flavor, texture and color of processed foods, and possible mechanisms explaining HPCD technique on the flavor, texture, and color of the foods were discussed.

  20. High-pressure refrigeration system with CO2 in automobile air-conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Wertenbach, J.; Kauf, F. [Daimler-Benz, Stuttgart (Germany)

    1998-12-31

    Due to high consumer acceptance of automobile air conditioning systems, the discussion of the effects of refrigerants on global warming is becoming more important to an environmentally-aware public. The consumption of fossil fuels to operate air conditioning systems, combined with refrigerant emissions, contribute to the greenhouse effect. Substitution of conventional refrigerants with CO2 reduces the load on heat-adsorbing gases in our atmosphere by providing an environment-friendly alternative. Because the amount of engine power devoted to air conditioning systems is limited, carbon dioxide makes an attractive substitute for HFC refrigerants in vehicle applications. In this paper, TEWI-figures for a vehicle with A/C System are considered, and the reduction potential due to CO2 as refrigerant as a motive for phasing out current technology is shown. This includes a comparison of COP`s between a conventional cold vapor cycle and the transcritical refrigerant cycle using CO2 to evaluate benefits and disadvantages. The high pressure refrigerant cycle has to be seen in the light of the requirement profile for introduced MACS. Furthermore, assorted results from the European RACE (Refrigeration and Automotive Climate systems under Environmental aspects) project are presented. The theory of the refrigerant cycle, tests results, packaging in a vehicle, and first experiences of component development are discussed, as well as difficulties in adapting this `Green Technology` to a car. 7 refs.

  1. Response of Rates and Sources of Ecosystem CO2 Efflux to Increasing Levels of Winter Snow Depth in the High Arctic of Northwest Greenland

    Science.gov (United States)

    Thomas, J. S.; Lupascu, M.; Xu, X.; Maseyk, K. S.; Welker, J. M.; Czimczik, C. I.

    2011-12-01

    Arctic soils contain vast amounts of organic carbon (C) that range in age from modern to ancient. These soil C pools may be especially vulnerable to changes in conditions; especially increases in winter snowfall, as deeper snow will insulate soils in winter, and add moisture in summer. While, snowfall is increasing in many parts of the Arctic, how increases in winter precipitation affect C cycling in the High Arctic is largely unknown. In this project, we used a long-term snowpack manipulation to develop a better understanding of current and future soil C cycling under conditions of deep winter snow pack and the associated feedbacks to future atmospheric CO2 levels. We examined the effects of three levels of winter snowpack (ambient (0.25 m), ×2, ×4) on the timing, magnitude and sources of ecosystem CO2 efflux and soil microclimate in prostrate dwarf-shrub tundra on patterned ground in the High Arctic of NW Greenland. From June to August 2010 and 2011 we monitored ecosystem CO2 efflux and soil CO2 concentrations (LI-COR 800 & 840) together with soil temperature and moisture daily and the radiocarbon (14C) content of CO2 monthly. The 14C content of CO2 can be used to infer the dominant source of CO2 (plant vs. microbially-respired) as well as the age of microbially-respired CO2. Initial results indicate that during the 2010 sampling period (Jun 28 - Aug 16), daily CO2 emissions from vegetated areas were higher under ×4 ambient snowpack relative to ambient snowpack (84.9 vs. 53.1 mmol m-2 d-1), but lower under ×2 ambient snowpack (56.7 mmol m-2 d-1). CO2 emissions from bare areas increased with snowpack depth from ambient (8.6 mmol m-2 d-1) to ×2 ambient snowpack (16.5 mmol m-2 d-1) to x4 ambient snowpack (18.9 mmol m-2 d-1). Midsummer ecosystem CO2 emissions were dominated by modern C; additional 14C measurements are in progress. Our findings indicate that increases in snowpack may stimulate C loss from this high arctic ecosystem - probably facilitated by

  2. A Convective Cloud Feedback and Spring Arctic Sea Ice Forecasting at High CO2

    Science.gov (United States)

    Abbot, D. S.; Walker, C. C.; Tziperman, E.

    2008-12-01

    Winter and spring sea ice dramatically cool the Arctic climate during the the coldest seasons of the year and may have remote effects on global climate as well. Accurate forecasting of winter and spring sea ice has significant social and economic benefits. Such forecasting requires the identification and understanding of all the feedbacks that can affect sea ice. A novel convective cloud feedback has recently been proposed in the context of explaining equable climates, e.g., the climate of the Eocene, that might be important for determining future winter and spring sea ice. In this feedback CO2 -initiated warming leads to sea ice reduction, which which allows increased heat and moisture fluxes from the ocean surface, which destabilizes the atmosphere and leads to atmospheric convection. This atmospheric convection produces high and optically thick convective clouds and increases high-altitude moisture levels, both of which trap outgoing longwave radiation and therefore result in a further warming and sea ice loss. Here it is shown that this convective cloud feedback is active during winter in the coupled ocean-sea ice-land-atmosphere global climate models used for the 1%/year CO2 increase to quadrupling scenario of the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report. It is further shown that the convective cloud feedback plays an essential role in the elimination of maximum seasonal (spring) sea ice in NCAR's CCSM model, one of the IPCC models that nearly completely loses spring sea ice. This is done by performing a sensitivity analysis using the atmospheric component of CCSM, run at a CO2 concentration of 1120 ppm, by selectively disabling the convective cloud feedback and the ocean heat transport feedback. The result is that both feedbacks are necessary for the elimination of spring sea ice at this CO2 concentration.

  3. Near-infrared spectroscopic study of a water-in-supercritical CO2 microemulsion as a function of the water content.

    Science.gov (United States)

    Takebayashi, Yoshihiro; Sagisaka, Masanobu; Sue, Kiwamu; Yoda, Satoshi; Hakuta, Yukiya; Furuya, Takeshi

    2011-05-19

    A water-in-supercritical CO(2) microemulsion is a reverse micelle encapsulating a nanometer-size water droplet dispersed in supercritical CO(2). In the microemulsion solution, water exists not only in the reverse micelle but also in the solvent CO(2). For quantitative analysis of the water distribution, near-infrared spectra of water + CO(2) and water + surfactant + CO(2) mixtures were measured over a wide range of water/CO(2) ratios from 0.1 to 1.0 wt% at 60 °C and 30.0 MPa. The stretching combination band of water was decomposed into two components, a sharp one peaked at 7194 cm(-1) assigned to monomeric water dissolved in CO(2) and a broad one around 7000 cm(-1) corresponding to aggregated water in the microemulsion. Integrated molar absorptivities of these types of water were negligibly different from each other, despite the different hydrogen-bonding environments. The spectral decomposition revealed that water is distributed mainly into CO(2) at water contents smaller than 0.5 wt% and then is introduced into the microemulsion after saturation of water in CO(2) and full hydration of the surfactant headgroup. © 2011 American Chemical Society

  4. Benefits of CO2 laser heating for high reliability fiber splicing

    Science.gov (United States)

    Duke, Douglas M.; Nasir, Usman; Saravanos, Elli

    2016-03-01

    The use of a CO2 laser as a heat source became commercially available for optical fiber splicing and component fabrication only in recent years. In addition to long-term trouble-free and low-maintenance heat source operation, laser fusion splicing offers unique benefits for fabricating high-power optical components, as well as for splice reliability. When used as the heating method for fiber splicing, the energy of the CO2 laser beam is efficiently absorbed by the outer layer of the glass, and is then conducted inwards. This heating method is well controlled, and results in a smooth and contamination-free glass surface. Other heating methods, such as arc fusion or resistive heating, may leave tungsten, graphite, or metal oxide deposits on the spliced fiber surface. By contrast, with CO2 laser splicing, the lack of surface irregularities and contamination enables remarkable spliced-fiber strength results, with some strength results nearly within the range of coated fiber breaking strength.

  5. High-Frequency, Automated Measurements of CO2, N2O and CH4 from Forested Soils

    Science.gov (United States)

    Savage, K. E.; Davidson, E. A.; Phillips, R. L.

    2011-12-01

    Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are the most important anthropogenic greenhouse gases. Soils are the dominant natural source of N2O, and fertilized agricultural soils are a major source of increasing anthropogenic N2O. Anthropogenic sources of CH4 include rice cultivation, while wetlands are a significant natural source, and upland soils are a natural CH4 sink. While most anthropogenic CO2 is derived from fossil fuel combustion, a significant fraction is from land use change, including a portion from loss of soil carbon. Soils play a central role as sources and sinks of the three most important anthropogenic greenhouse gases of the 21st century, CO2, CH4, and N2O. Variation in soil moisture can be very dynamic, and it is one of the dominant factors controlling soil aeration, and hence the balance between aerobic (CO2 producing) and anaerobic (CH4 producing) respiration. The production and consumption of N2O is also highly dependent on spatial and temporal variation in soil moisture. Although technologies for high frequency, precise measurements of CO2 have been available for years, methods for measuring soil fluxes of CH4 and N2O at high temporal frequency have been hampered by lack of appropriate technology for in situ real-time measurements. We utilized a previously developed automated chamber system for measuring CO2 efflux (Licor 6252 IRGA) from soils, and configured it to run in-line with a new model quantum cascade laser (QCL) system which measures N2O and CH4 (Aerodyne model QC-TILDAS-CS). The QCL is thermoelectrically cooled and uses a 76-meter path length, 0.5 liter volume, and multiple pass absorption cell for sampling. The QCL sampling frequency is 10Hz, and its range is 0.3 to 3000 ppb for N2O with a sensitivity of 0.3 ppb, and 0.5 to 5000 ppb for CH4 with a sensitivity of 0.5 ppb. Six sampling chambers, with corresponding soil water content and soil temperature sensors, were deployed at the Howland Forest ME, in an upland

  6. Predation in High CO2 Waters: Prey Fish from High-Risk Environments are Less Susceptible to Ocean Acidification.

    Science.gov (United States)

    Ferrari, Maud C O; McCormick, Mark I; Watson, Sue-Ann; Meekan, Mark G; Munday, Philip L; Chivers, Douglas P

    2017-07-01

    Most studies investigating the effects of anthropogenic environmental stressors do so in conditions that are often optimal for their test subjects, ignoring natural stressors such as competition or predation. As such, the quantitative results from such studies may often underestimate the lethality of certain toxic compounds. A well-known example of this concept is illustrated by the marked increase in the lethality of pesticides when larval amphibians are concurrently exposed to the odor of potential predators. Here, we investigated the interaction between background levels of environmental predation risk (high vs. low) and ocean acidification (ambient vs. elevated CO2) in 2 × 2 design. Wild-caught juvenile damselfish, Pomacentrus amboinensis, were exposed in the laboratory to the different risk and CO2 conditions for 4 days and released onto coral reef patches. Using a well-established field assay, we monitored the in situ behavior and mortality of the damselfish for 2 days. We predicted that juvenile fish exposed to elevated CO2 and high-risk conditions would display more severe behavioral impairments and increased mortality compared to fish exposed to elevated CO2 maintained under low-risk conditions. As expected, elevated CO2 exposure led to impaired antipredator responses and increased mortality in low-risk fish compared to ambient CO2 controls. However, we failed to find an effect of elevated CO2 on the behavior and survival of the high-risk fish. We hypothesized that the results may stem from either a behavioral compensation or a physiological response to high risk. Our results provide insights into the interactive nature of environmental and natural stressors and advance our understanding of the predicted effect of ocean acidification on aquatic ecosystems. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  7. 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

  8. 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 CO2 (0.04 % in ambient air) with Li anode may lead to the irreversible formation of insulating Li2 CO3 , making the battery less rechargeable. To make the Li-CO2 batteries usable under ambient conditions, it is critical to develop highly efficient catalysts for the CO2 reduction and evolution reactions and investigate the electrochemical behavior of Li-CO2 batteries. Here, we demonstrate a rechargeable Li-CO2 battery with a high reversibility by using B,N-codoped holey graphene as a highly efficient catalyst for CO2 reduction and evolution reactions. Benefiting from the unique porous holey nanostructure and high catalytic activity of the cathode, the as-prepared Li-CO2 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 CO2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High-Yield Process for Selectively Converting CO2 to Aromatics and Olefins Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Phase I addresses the selective conversion of CO2 to hydrocarbons via integrated CO2-to-methanol, methanol-to-olefins, and olefins-to-aromatics...

  10. High-Precision Instrumentation for CO2 Isotope Ratio Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Knowing atmospheric 13CO2/12CO2 ratios precisely is important to understanding biogenic and anthroprogenic sources and sinks for carbon. Currently available field...

  11. Evaluating atmospheric CO2 inversions at multiple scales over a highly-inventoried agricultural landscape.

    Energy Technology Data Exchange (ETDEWEB)

    Schuh, Andrew E.; Lauvaux, Thomas; West, Tristram O.; Denning, A.; Davis, Kenneth J.; Miles, Natasha; Richardson, S. J.; Uliasz, Marek; Lokupitiya, Erandathie; Cooley, Dan; Andrews, Arlyn; Ogle, Stephen

    2013-05-01

    An intensive regional research campaign was conducted by the North American Carbon Program (NACP) in 2005 to study the carbon cycle of the highly productive agricultural regions of the Midwestern United States. Forty-_ve di_erent associated projects were spawned across _ve U.S. agencies over the course of nearly a decade involving hundreds of researchers. The primary objective of the project was to investigate the ability of atmospheric inversion techniques to use highly calibrated CO2 mixing ratio data to estimate CO2 exchange over the major croplands of the U.S. Statistics from densely monitored crop production, consisting primarily corn and soybeans, provided the backbone of a well-studied\\bottom up"flux estimate that was used to evaluate the atmospheric inversion results. Three different inversion systems, representing spatial scales varying from high resolution mesoscale, to continental, to global, coupled to different transport models and optimization techniques were compared to the bottom up" inventory estimates. The mean annual CO2-C sink for 2007 from the inversion systems ranged from 120 TgC to 170 TgC, when viewed across a wide variety of inversion setups, with the best" point estimates ranging from 145 TgC to 155 TgC. Inversion-based mean C sink estimates were generally slightly stronger, but statistically indistinguishable,from the inventory estimate whose mean C sink was 135 TgC. The inversion results showed temporal correlations at seasonal lengths while week to week correlations remained low. Comparisons were made between atmospheric transport yields of the two regional inversion systems, which despite having different influence footprints in space and time due to differences in underlying transport models and external forcings, showed similarity when aggregated in space and time.

  12. Molecular basis for the high CO2 adsorption capacity of chabazite zeolites.

    Science.gov (United States)

    Pham, Trong D; Hudson, Matthew R; Brown, Craig M; Lobo, Raul F

    2014-11-01

    CO2 adsorption in Li-, Na-, K-CHA (Si/Al=6,=12), and silica chabazite zeolites was investigated by powder diffraction. Two CO2 adsorption sites were found in all chabazites with CO2 locating in the 8-membered ring (8MR) pore opening being the dominant site. Electric quadrupole-electric field gradient and dispersion interactions drive CO2 adsorption at the middle of the 8 MRs, while CO2 polarization due to interaction with cation sites controls the secondary CO2 site. In Si-CHA, adsorption is dominated by dispersion interactions with CO2 observed on the pore walls and in 8 MRs. CO2 adsorption complexes on dual cation sites were observed on K-CHA, important for K-CHA-6 samples due to a higher probability of two K(+) cations bridging CO2. Trends in isosteric heats of CO2 adsorption based on cation type and concentration can be correlated with adsorption sites and CO2 quantity. A decrease in the hardness of metal cations results in a decrease in the direct interaction of these cations with CO2. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Dentin bond strength after ablation using a CO2 laser operating at high pulse repetition rates

    Science.gov (United States)

    Hedayatollahnajafi, Saba; Staninec, Michal; Watanabe, Larry; Lee, Chulsung; Fried, Daniel

    2009-02-01

    Pulsed CO2 lasers show great promise for the rapid and efficient ablation of dental hard tissues. Our objective was to demonstrate that CO2 lasers operated at high repetition rates can be used for the rapid removal of dentin without excessive thermal damage and without compromising adhesion to restorative materials. Human dentin samples (3x3mm2) were rapidly ablated with a pulsed CO2 laser operating at a wavelength of 9.3-µm, pulse repetition rate of 300-Hz and an irradiation intensity of 18-J/cm2. The bond strength to composite was determined by the modified single plane shear test. There were 8 test groups each containing 10 blocks: negative control (non-irradiated non-etched), positive control (non-irradiated acid-etched), and six laser treated groups (three etched and three non-etched sets). The first and second etched and non-etched sets were ablated at a speed of 25 mm/sec and 50 mm/sec with water, respectively. The third set was also ablated at 50 mm/sec without application of water during laser irradiation. Minimal thermal damage was observed on the dentin surfaces for which water cooling was applied. Bond strengths exceeded 20 MPa for laser treated surfaces that were acid-etched after ablation (25-mm/sec: 29.9-MPa, 50-mm/sec: 21.3-MPa). The water-cooled etched laser groups all produced significantly stronger bonds than the negative control (pbond strength than the positive control (pbond strength than the acid-etched control samples is clinically significant where durability of these bonded restoration supersedes high bond strength.

  14. Hypercapnia Accelerates Adipogenesis: A Novel Role of High CO2 in Exacerbating Obesity.

    Science.gov (United States)

    Kikuchi, Ryota; Tsuji, Takao; Watanabe, Osamu; Yamaguchi, Kazuhiro; Furukawa, Kinya; Nakamura, Hiroyuki; Aoshiba, Kazutetsu

    2017-11-01

    Obesity is a major risk factor for the development of obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS), which manifest as intermittent hypercapnia and sustained plus intermittent hypercapnia, respectively. In this study, we investigated whether CO2 affects adipocyte differentiation (adipogenesis) and maturation (hypertrophy). Human visceral or subcutaneous preadipocytes were grown to confluence and then induced to differentiate to adipocytes under hypocapnia, normocapnia, and hypercapnia with or without hypoxia. Adipogenesis was also induced under intermittent or sustained hypercapnia. Differentiated adipocytes were maintained to maturity under normocapnia or hypercapnia. Our main findings are as follows: (1) hypercapnia accelerated adipogenesis in visceral and subcutaneous preadipocytes, whereas hypocapnia inhibited adipogenesis; (2) hypercapnia did not affect adipocyte hypertrophy; (3) hypercapnia-accelerated adipogenesis was independent of extracellular acidosis, oxygen concentration, or either intermittent or sustained exposure to high CO2; and (4) the mechanisms underlying hypercapnia-accelerated adipogenesis involved increased production of cyclic adenosine monophosphate (cAMP) via soluble adenylyl cyclase, leading to the activation of protein kinase A and exchanger protein directly activated by cAMP, which, in turn, activated proadipogenic transcription factors, such as cAMP response element binding protein, CCAAT/enhancer binding protein β, and peroxisome proliferator-activated receptor γ. This study reveals a novel role of high CO2 in promoting adipogenesis, which provides mechanistic clues to a pathoetiological interaction between OSA/OHS and obesity. Our data suggest a vicious cycle of disease progression via the following mechanism: OSA/OHS → hypoventilation → hypercapnia → increased adipogenesis → increased fat mass → exacerbated OSA/OHS.

  15. 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.

  16. Highly Permeable Graphene Oxide/Polyelectrolytes Hybrid Thin Films for Enhanced CO2/N2 Separation Performance.

    Science.gov (United States)

    Heo, Jiwoong; Choi, Moonhyun; Chang, Jungyun; Ji, Dahye; Kang, Sang Wook; Hong, Jinkee

    2017-03-28

    Separation of CO2 from other gasses offers environmental benefits since CO2 gas is the main contributor to global warming. Recently, graphene oxide (GO) based gas separation membranes are of interest due to their selective barrier properties. However, maintaining selectivity without sacrificing permeance is still challenging. Herein, we described the preparation and characterization of nanoscale GO membranes for CO2 separation with both high selectivity and permeance. The internal structure and thickness of the GO membranes were controlled by layer-by-layer (LbL) self-assembly. Polyelectrolyte layers are used as the supporting matrix and for facilitating CO2 transport. Enhanced gas separation was achieved by adjusting pH of the GO solutions and by varying the number of GO layers to provide a pathway for CO2 molecules. Separation performance strongly depends on the number of GO bilayers. The surfaces of the multilayered GO and polyelectrolyte films are characterized by atomic force microscopy and scanning electron microscopy. The (poly (diallyldimethylammonium chloride) (PDAC)/polystyrene sulfonate (PSS)) (GO/GO) multilayer membranes show a maximum CO2/N2 selectivity of 15.3 and a CO2 permeance of 1175.0 GPU. LbL-assembled GO membranes are shown to be effective candidates for CO2 separation based on their excellent CO2/N2 separation performance.

  17. Ultraviolet (UV) Raman Spectroscopy Study of the Soret Effect in High-Pressure CO2-Water Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Maupin, Gary D.; McGrail, B. Peter

    2012-07-01

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O or D2O subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O, at 10 MPa and temperatures near the critical point of CO2, had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19 C. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for D2O were too weak to measure with confidence even at the limit of D2O solubility.

  18. 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...

  19. 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.

  20. High temperatures and high pressures Brillouin scattering studies of liquid H(2)O+CO(2) mixtures.

    Science.gov (United States)

    Qin, Junfeng; Li, Min; Li, Jun; Chen, Rongyan; Duan, Zhenhao; Zhou, Qiang; Li, Fangfei; Cui, Qiliang

    2010-10-21

    The Brillouin scattering spectroscopy studies have been conducted in a diamond anvil cell for a liquid mixtures composed of 95 mol % H(2)O and 5 mol % CO(2) under high temperatures and pressures. The sound velocity, refractive index, density, and adiabatic bulk modulus of the H(2)O+CO(2) mixtures were determined under pressures up to the freezing point at 293, 453, and 575 K. It is found from the experiment that sound velocities of the liquid mixture are substantially lower than those of pure water at 575 K, but not at lower temperatures. We presented an empirical relation of the density in terms of pressure and temperature. Our results show that liquid H(2)O+CO(2) mixtures are more compressible than water obtained from an existing equation of state of at 453 and 575 K.

  1. Janus Reactors with Highly Efficient Enzymatic CO2Nanocascade at Air-Liquid Interface.

    Science.gov (United States)

    Gao, Song; Mohammad, Munirah; Yang, Hao-Cheng; Xu, Jia; Liang, Kang; Hou, Jingwei; Chen, Vicki

    2017-12-13

    Though enzymatic cascade reactors have been the subject of intense research over the past few years, their application is still limited by the complicated fabrication protocols, unsatisfactory stability and lack of effective reactor designs. In addition, the spatial positioning of the cascade reactor has so far not been investigated, which is of significant importance for biphase catalytic reaction systems. Inspired by the Janus properties of the lipid cellular membrane, here we show a highly efficient Janus gas-liquid reactor for CO 2 hydration and conversion. Within the Janus reactor, nanocascades containing the nanoscale compartmentalized carbonic anhydrase and formic dehydrogenase were positioned at a well-defined gas-liquid interface, with a high substrate concentration gradient. The Janus reactor exhibited 2.5 times higher CO 2 hydration efficiency compared with the conventional gas-liquid contactor with pristine membranes, and the formic acid conversion rate can reach approximately 90%. Through this work, we provide evidence that the spatial arrangement of the nanocascade is also crucial to efficient reactions, and the Janus reactor can be a promising candidate for the biphase catalytic reactions in environmental, biological and energy aspects.

  2. Toward observationally constrained high space and time resolution CO2 urban emission inventories

    Science.gov (United States)

    Maness, H.; Teige, V. E.; Wooldridge, P. J.; Weichsel, K.; Holstius, D.; Hooker, A.; Fung, I. Y.; Cohen, R. C.

    2013-12-01

    The spatial patterns of greenhouse gas (GHG) emission and sequestration are currently studied primarily by sensor networks and modeling tools that were designed for global and continental scale investigations of sources and sinks. In urban contexts, by design, there has been very limited investment in observing infrastructure, making it difficult to demonstrate that we have an accurate understanding of the mechanism of emissions or the ability to track processes causing changes in those emissions. Over the last few years, our team has built a new high-resolution observing instrument to address urban CO2 emissions, the BErkeley Atmospheric CO2 Observing Network (BEACON). The 20-node network is constructed on a roughly 2 km grid, permitting direct characterization of the internal structure of emissions within the San Francisco East Bay. Here we present a first assessment of BEACON's promise for evaluating the effectiveness of current and upcoming local emissions policy. Within the next several years, a variety of locally important changes are anticipated--including widespread electrification of the motor vehicle fleet and implementation of a new power standard for ships at the port of Oakland. We describe BEACON's expected performance for detecting these changes, based on results from regional forward modeling driven by a suite of projected inventories. We will further describe the network's current change detection capabilities by focusing on known high temporal frequency changes that have already occurred; examples include a week of significant freeway traffic congestion following the temporary shutdown of the local commuter rail (the Bay Area Rapid Transit system).

  3. 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.

  4. High Repetition Rate Pulsed 2-Micron Laser Transmitter for Coherent CO2 DIAL Measurement

    Science.gov (United States)

    Singh, Uprendra N.; Bai, Yingxin; Yu, Jirong; Petros, Mulugeta; Petzar, Paul J.; Trieu, Bo C.; Lee, Hyung

    2009-01-01

    A high repetition rate, highly efficient, Q-switched 2-micron laser system as the transmitter of a coherent differential absorption lidar for CO2 measurement has been developed at NASA Langley Research Center. Such a laser transmitter is a master-slave laser system. The master laser operates in a single frequency, either on-line or off-line of a selected CO2 absorption line. The slave laser is a Q-switched ring-cavity Ho:YLF laser which is pumped by a Tm:fiber laser. The repetition rate can be adjusted from a few hundred Hz to 10 kHz. The injection seeding success rate is from 99.4% to 99.95%. For 1 kHz operation, the output pulse energy is 5.5mJ with the pulse length of approximately 50 ns. The optical-to-optical efficiency is 39% when the pump power is 14.5W. The measured standard deviation of the laser frequency jitter is about 3 MHz.

  5. Utility of deep sea CO2 release experiments in understanding the biology of a high-CO2 ocean: Effects of hypercapnia on deep sea meiofauna

    Science.gov (United States)

    Barry, James P.; Buck, Kurt R.; Lovera, Chris; Kuhnz, Linda; Whaling, Patrick J.

    2005-09-01

    Oceanic CO2 levels are expected to rise during the next 2 centuries to levels not seen for 10-150 million years by the uptake of atmospheric CO2 in surface waters or potentially through the disposal of waste CO2 in the deep sea. Changes in ocean chemistry caused by CO2 influx may have broad impacts on ocean ecosystems. Physiological processes animals use to cope with CO2-related stress are known, but the range of sensitivities and effects of changes in ocean chemistry on most ocean life remain unclear. We evaluate the effectiveness of various designs for in situ CO2 release experiments in producing stable perturbations in seawater chemistry over experimental seafloor plots, as is desirable for evaluating the CO2 sensitivities of deep sea animals. We also discuss results from a subset of these experiments on the impacts of hypercapnia on deep sea meiofauna, in the context of experimental designs. Five experiments off central California show that pH perturbations were greatest for experiments using "point source" CO2 pools surrounded by experimental plots. CO2 enclosure experiments with experimental plots positioned within a circular arrangement of CO2 pools had more moderate pH variation. The concentration of dissolution plumes from CO2 pools were related to the speed and turbulence of near-bottom currents, which influence CO2 dissolution and advection. Survival of meiofauna (nematodes, amoebae, euglenoid flagellates) was low after episodic severe hypercapnia but lower and variable where pH changes ranged from 0 to 0.2 pH units below normal.

  6. A sublimation technique for high-precision d13C on CO2 and CO2 mixing ratio from air trapped in deep ice cores

    OpenAIRE

    Schmitt, Jochen

    2006-01-01

    Glacier ice represents the only direct archive to retrieve information about the composition of the paleoatmosphere. During the glacials the CO2 concentration was about 90 ppmv lower than during the warm interglacials. The task to quantitatively understand the processes behind these observed CO2 changes is of outstanding importance not only for the paleo climate community, but also to predict the CO2 concentration in the future. One crucial key to unravel the open questions about the coupling...

  7. Variation of photoautotrophic fatty acid production from a highly CO2 tolerant alga, Chlorococcum littorale, with inorganic carbon over narrow ranges of pH.

    Science.gov (United States)

    Ota, Masaki; Takenaka, Motohiro; Sato, Yoshiyuki; Smith, Richard L; Inomata, Hiroshi

    2015-01-01

    Photoautotrophic fatty acid production of a highly CO2 -tolerant green alga Chlorococcum littorale in the presence of inorganic carbon at 295 K and light intensity of 170 µmol-photon m(-2) s(-1) was investigated. CO2 concentration in the bubbling gas was adjusted by mixing pure gas components of CO2 and N2 to avoid photorespiration and β-oxidation of fatty acids under O2 surrounding conditions. Maximum content of total fatty acid showed pH-dependence after nitrate depletion of the culture media and increased with the corresponding inorganic carbon ratio. Namely, [HCO3 (-) ]/([CO2 ]+n[ CO32-]) ratio in the culture media was found to be a controlling factor for photoautotrophic fatty acid production after the nitrate limitation. At a CO2 concentration of 5% (vol/vol) and a pH of 6.7, the fatty acid content was 47.8 wt % (dry basis) at its maximum that is comparable with land plant seed oils. © 2015 American Institute of Chemical Engineers.

  8. High-performance multilayer composite membranes with mussel-inspired polydopamine as a versatile molecular bridge for CO2 separation.

    Science.gov (United States)

    Li, Panyuan; Wang, Zhi; Li, Wen; Liu, Yanni; Wang, Jixiao; Wang, Shichang

    2015-07-22

    It is desirable to develop high-performance composite membranes for efficient CO2 separation in CO2 capture process. Introduction of a highly permeable polydimethylsiloxane (PDMS) intermediate layer between a selective layer and a porous support has been considered as a simple but efficient way to enhance gas permeance while maintaining high gas selectivity, because the introduced intermediate layer could benefit the formation of an ultrathin defect-free selective layer owing to the circumvention of pore penetration phenomenon. However, the selection of selective layer materials is unfavorably restricted because of the low surface energy of PDMS. Various highly hydrophilic membrane materials such as amino group-rich polyvinylamine (PVAm), a representative facilitated transport membrane material for CO2 separation, could not be facilely coated over the surface of the hydrophobic PDMS intermediate layer uniformly. Inspired by the hydrophilic nature and strong adhesive ability of polydopamine (PDA), PDA was therefore selected as a versatile molecular bridge between hydrophobic PDMS and hydrophilic PVAm. The PDA coating endows a highly compatible interface between both components with a large surface energy difference via multiple-site cooperative interactions. The resulting multilayer composite membrane with a thin facilitated transport PVAm selective layer exhibits a notably enhanced CO2 permeance (1887 GPU) combined with a slightly improved CO2/N2 selectivity (83), as well as superior structural stability. Similarly, the multilayer composite membrane with a hydrophilic CO2-philic Pebax 1657 selective layer was also developed for enhanced CO2 separation performance.

  9. 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.

  10. 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.

  11. 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.

  12. Longitudinally excited CO2 laser with short laser pulse operating at high repetition rate

    Science.gov (United States)

    Li, Jianhui; Uno, Kazuyuki; Akitsu, Tetsuya; Jitsuno, Takahisa

    2016-11-01

    A short-pulse longitudinally excited CO2 laser operating at a high repetition rate was developed. The discharge tube was made of a 45 cm-long or 60 cm-long dielectric tube with an inner diameter of 16 mm and two metallic electrodes at the ends of the tube. The optical cavity was formed by a ZnSe output coupler with a reflectivity of 85% and a high-reflection mirror. Mixed gas (CO2:N2:He = 1:1:2) was flowed into the discharge tube. A high voltage of about 33 kV with a rise time of about 200 ns was applied to the discharge tube. At a repetition rate of 300 Hz and a gas pressure of 3.4 kPa, the 45 cm-long discharge tube produced a short laser pulse with a laser pulse energy of 17.5 mJ, a spike pulse energy of 0.2 mJ, a spike width of 153 ns, and a pulse tail length of 90 μs. The output power was 5.3 W. The laser pulse waveform did not depend on the repetition rate, but the laser beam profile did. At a low repetition rate of less than 50 Hz, the laser beam had a doughnut-like shape. However, at a high repetition rate of more than 150 Hz, the discharge concentrated at the center of the discharge tube, and the intensity at the center of the laser beam was higher. The laser beam profile depended on the distribution of the discharge. An output power of 7.0 W was achieved by using the 60 cm-long tube.

  13. [Measurements of CO2 concentration at high temperature and pressure environments using tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Cai, Ting-Dong; Gao, Guang-Zhen; Wang, Min-Rui; Wang, Gui-Shi; Gao, Xiao-Ming

    2014-07-01

    The present research was planned to develop a method for species concentration measurements under high temperature and pressure environments. The characteristics of CO2 spectrum at high temperature and pressure were studied at first. Based on the research above, tunable diode-laser absorption of CO2 near 2.0 microm incorporating fixed-wavelength modulation spectroscopy with second-harmonic detection was used to provide a method for sensitive and accurate measurements of gas temperature and CO2 concentration at high temperature and pressure. Measurements were performed in a well-controlled high temperature and pressure static cell. The results show that the average error of the CO2 concentration measurements at 5 atm, 500 K and 10 atm, 1000 K is 4. 49%. All measurements show the accuracy and potential utility of the method for high temperature and pressure diagnostics.

  14. High Temperature, High Ambient CO2 Affect the Interactions between Three Positive-Sense RNA Viruses and a Compatible Host Differentially, but not Their Silencing Suppression Efficiencies

    Science.gov (United States)

    Del Toro, Francisco J.; Aguilar, Emmanuel; Hernández-Walias, Francisco J.; Tenllado, Francisco; Chung, Bong-Nam; Canto, Tomas

    2015-01-01

    We compared infection of Nicotiana benthamiana plants by the positive-sense RNA viruses Cucumber mosaic virus (CMV), Potato virus Y (PVY), and by a Potato virus X (PVX) vector, the latter either unaltered or expressing the CMV 2b protein or the PVY HCPro suppressors of silencing, at 25°C vs. 30°C, or at standard (~401 parts per million, ppm) vs. elevated (970 ppm) CO2 levels. We also assessed the activities of their suppressors of silencing under those conditions. We found that at 30°C, accumulation of the CMV isolate and infection symptoms remained comparable to those at 25°C, whereas accumulation of the PVY isolate and those of the three PVX constructs decreased markedly, even when expressing the heterologous suppressors 2b or HCPro, and plants had either very attenuated or no symptoms. Under elevated CO2 plants grew larger, but contained less total protein/unit of leaf area. In contrast to temperature, infection symptoms remained unaltered for the five viruses at elevated CO2 levels, but viral titers in leaf disks as a proportion of the total protein content increased in all cases, markedly for CMV, and less so for PVY and the PVX constructs. Despite these differences, we found that neither high temperature nor elevated CO2 prevented efficient suppression of silencing by their viral suppressors in agropatch assays. Our results suggest that the strength of antiviral silencing at high temperature or CO2 levels, or those of the viral suppressors that counteract it, may not be the main determinants of the observed infection outcomes. PMID:26313753

  15. Seasonally varying contributions to urban CO2 in the Chicago, Illinois, USA region: Insights from a high-resolution CO2 concentration and δ13C record

    Directory of Open Access Journals (Sweden)

    Joel Moore

    2015-06-01

    Full Text Available Abstract Understanding urban carbon cycling is essential given that cities sustain 54% of the global population and contribute 70% of anthropogenic CO2 emissions. When combined with CO2 concentration measurements ([CO2], stable carbon isotope analyses (δ13C can differentiate sources of CO2, including ecosystem respiration and combustion of fossil fuels, such as petroleum and natural gas. In this study, we used a wavelength scanned-cavity ringdown spectrometer to collect ∼2x106 paired measurements for [CO2] and δ13C values in Evanston, IL for August 2011 through February 2012. Evanston is located immediately north of Chicago, IL, the third largest city in the United States. The measurements represent one of the longest records of urban [CO2] and δ13C values thus far reported. We also compiled local meteorological information, as well as complementary [CO2] and δ13C data for background sites in Park Falls, WI and Mauna Loa, HI. We use the dataset to examine how ecosystem processes, fossil fuel usage, wind speed, and wind direction control local atmospheric [CO2] and δ13C in a midcontinent urban setting on a seasonal to daily basis. On average, [CO2] and δ13C values in Evanston were 16–23 ppm higher and 0.97–1.13‰ lower than the background sites. While seasonal [CO2] and δ13C values generally followed broader northern hemisphere trends, the difference between Evanston and the background sites was larger in winter versus summer. Mixing calculations suggest that ecosystem respiration and petroleum combustion equally contributed CO2 in excess of background during the summer and that natural gas combustion contributed 80%–94% of the excess CO2 in winter. Wind speed and direction strongly influenced [CO2] and δ13C values on an hourly time scale. The highest [CO2] and lowest δ13C values occurred at wind speeds <3 m s−1 and when winds blew from the northwest, west, and south over densely populated neighborhoods.

  16. The response to high CO2 levels requires the neuropeptide secretion component HID-1 to promote pumping inhibition.

    Directory of Open Access Journals (Sweden)

    Kfir Sharabi

    2014-08-01

    Full Text Available Carbon dioxide (CO2 is a key molecule in many biological processes; however, mechanisms by which organisms sense and respond to high CO2 levels remain largely unknown. Here we report that acute CO2 exposure leads to a rapid cessation in the contraction of the pharynx muscles in Caenorhabditis elegans. To uncover the molecular mechanisms underlying this response, we performed a forward genetic screen and found that hid-1, a key component in neuropeptide signaling, regulates this inhibition in muscle contraction. Surprisingly, we found that this hid-1-mediated pathway is independent of any previously known pathways controlling CO2 avoidance and oxygen sensing. In addition, animals with mutations in unc-31 and egl-21 (neuropeptide secretion and maturation components show impaired inhibition of muscle contraction following acute exposure to high CO2 levels, in further support of our findings. Interestingly, the observed response in the pharynx muscle requires the BAG neurons, which also mediate CO2 avoidance. This novel hid-1-mediated pathway sheds new light on the physiological effects of high CO2 levels on animals at the organism-wide level.

  17. 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.

  18. Impact of high pCO2 on shell structure of the bivalve Cerastoderma edule.

    Science.gov (United States)

    Milano, Stefania; Schöne, Bernd R; Wang, Schunfeng; Müller, Werner E

    2016-08-01

    Raised atmospheric emissions of carbon dioxide (CO2) result in an increased ocean pCO2 level and decreased carbonate saturation state. Ocean acidification potentially represents a major threat to calcifying organisms, specifically mollusks. The present study focuses on the impact of elevated pCO2 on shell microstructural and mechanical properties of the bivalve Cerastoderma edule. The mollusks were collected from the Baltic Sea and kept in flow-through systems at six different pCO2 levels from 900 μatm (control) to 24,400 μatm. Extreme pCO2 levels were used to determine the effects of potential leaks from the carbon capture and sequestration sites where CO2 is stored in sub-seabed geological formations. Two approaches were combined to determine the effects of the acidified conditions: (1) Shell microstructures and dissolution damage were analyzed using scanning electron microscopy (SEM) and (2) shell hardness was tested using nanoindentation. Microstructures of specimens reared at different pCO2 levels do not show significant changes in their size and shape. Likewise, the increase of pCO2 does not affect shell hardness. However, dissolution of ontogenetically younger portions of the shell becomes more severe with the increase of pCO2. Irrespective of pCO2, strong negative correlations exist between microstructure size and shell mechanics. An additional sample from the North Sea revealed the same microstructural-mechanical interdependency as the shells from the Baltic Sea. Our findings suggest that the skeletal structure of C. edule is not intensely influenced by pCO2 variations. Furthermore, our study indicates that naturally occurring shell mechanical property depends on the shell architecture at μm-scale. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. High-stability non-invasive autoclavable naked optical CO2 sensor.

    Science.gov (United States)

    Ge, Xudong; Kostov, Yordan; Rao, Govind

    2003-07-01

    The fabrication and characterization of a high-stability non-invasive autoclavable naked optical CO(2) sensor is described in this report. The sensor was made by using 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) as the fluorescence dye and cetyltrimethylammonium hydroxide (CTMAOH) as the phase transfer agent (the base). A highly hydrophobic two-component silicone film was used as the polymer matrix, which overcame some of the limitations of the existing plastic type CO(2) sensors, such as dye leaching and cross-sensitivity to ions. To improve the stability of the sensor, several affecting factors were investigated. Experimental results showed that sufficient base and a small amount of water in the sensing film were critical factors that affected the stability of the sensor. Although the sensor was more stable when kept in water, the function of the sensor could recover when the sensor kept in air was transferred into water. The sensor has a lifetime of several months. The detection limit of the sensing film was about 0.03%. The average response and recovery times were 0.66 and 1.94 min, respectively. It had no cross-sensitivity to salt concentrations in the range of 0-0.2 M and to pH in the range of 5.6-8.0, so it can be used in processes with changing ion concentration and pH. It was sterilizable and could be autoclaved many times without losing its sensitivity. The applicability of the sensor in real application was successfully tested in the fermentation of Escherichia coli.

  20. Pore space partition and charge separation in cage-within-cage indium-organic frameworks with high CO2 uptake.

    Science.gov (United States)

    Zheng, Shou-Tian; Bu, Julia T; Li, Yufei; Wu, Tao; Zuo, Fan; Feng, Pingyun; Bu, Xianhui

    2010-12-08

    The integration of negatively charged single-metal building blocks {In(CO2)4} and positively charged trimeric clusters {In3O} leads to three unique cage-within-cage-based porous materials, which exhibit not only high hydrothermal, thermal, and photochemical stability but also attractive structural features contributing to a very high CO2 uptake capacity of up to 119.8 L/L at 273 K and 1 atm.

  1. Simple, compact, and low cost CO2 laser driven by fast high voltage solid state switch for industrial application

    Science.gov (United States)

    Tanaka, Miyu; Tei, Masaya; Uno, Kazuyuki; Nakano, Hitoshi

    2017-02-01

    A longitudinally excited CO2 laser driven with a reverse recovery characteristics of high voltage diode has been developed. A diode is used to control the high voltage pulse as an opening switch. Power supply for longitudinally excited CO2 laser is composed of a pulse generator, transformer, capacitor, and a diode, is very simple. Laser oscillation has been successfully achieved, several tens of mJ in laser energy has been obtained.

  2. Isolation of Cu Atoms in Pd Lattice: Forming Highly Selective Sites for Photocatalytic Conversion of CO2 to CH4.

    Science.gov (United States)

    Long, Ran; Li, Yu; Liu, Yan; Chen, Shuangming; Zheng, Xusheng; Gao, Chao; He, Chaohua; Chen, Nanshan; Qi, Zeming; Song, Li; Jiang, Jun; Zhu, Junfa; Xiong, Yujie

    2017-03-29

    Photocatalytic conversion of CO2 to CH4, a carbon-neutral fuel, represents an appealing approach to remedy the current energy and environmental crisis; however, it suffers from the large production of CO and H2 by side reactions. The design of catalytic sites for CO2 adsorption and activation holds the key to address this grand challenge. In this Article, we develop highly selective sites for photocatalytic conversion of CO2 to CH4 by isolating Cu atoms in Pd lattice. According to our synchrotron-radiation characterizations and theoretical simulations, the isolation of Cu atoms in Pd lattice can play dual roles in the enhancement of CO2-to-CH4 conversion: (1) providing the paired Cu-Pd sites for the enhanced CO2 adsorption and the suppressed H2 evolution; and (2) elevating the d-band center of Cu sites for the improved CO2 activation. As a result, the Pd7Cu1-TiO2 photocatalyst achieves the high selectivity of 96% for CH4 production with a rate of 19.6 μmol gcat-1 h-1. This work provides fresh insights into the catalytic site design for selective photocatalytic CO2 conversion, and highlights the importance of catalyst lattice engineering at atomic precision to catalytic performance.

  3. 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.

  4. High pressure solubility of carbon dioxide (CO2) in aqueous solution of piperazine (PZ) activated N-methyldiethanolamine (MDEA) solvent for CO2 capture

    Science.gov (United States)

    Khan, Saleem Nawaz; Hailegiorgis, Sintayehu Mekuria; Man, Zakaria; Shariff, Azmi Mohd

    2017-10-01

    In this study, the solubility of carbon dioxide (CO2) in the aqueous solution of piperazine (PZ) activated N-methyldiethanolamine (MDEA) was investigated. In the aqueous solution the concentrations of the N-methyldiethanolamine (MDEA) and piperazine (PZ) were kept constant at 30 wt. % and 3 wt. %, respectively. The solubility experiments were carried out between the temperatures ranges of 303.15 to 333.15 K. The pressure range was selected as 2-50 bar for solubility of carbon dioxide in the aqueous solution. The solubility of the CO2 is reported in terms of CO2 loading capacity of the solvent. The loading capacity of the solvent is the ratio between the numbers of moles of CO2 absorbed to the numbers of moles of solvent used. The experimental data showed that the CO2 loading increased with increase in CO2 partial pressure, while it decreased with increase in system's temperature. It was also observed from the experimental data that the higher pressure favors the absorption process while the increased temperature hinders the absorption process of CO2 capture. The loading capacity of the investigated solvent was compared with the loading capacity of the solvents reported in the literature. The investigated solvent showed better solubility in terms of loading capacity.

  5. Characterization of the physicochemical properties of phospholipid vesicles prepared in CO2/water systems at high pressure.

    Science.gov (United States)

    Nakamura, Hidemi; Taguchi, Shogo; Suga, Keishi; Hayashi, Keita; Jung, Ho-Sup; Umakoshi, Hiroshi

    2015-09-21

    Phospholipid vesicles were prepared by the nonsolvent method using high-pressure CO2/water systems. The membrane properties of vesicles prepared at different pressures and temperatures were mainly characterized based on analysis of the membrane fluidity and membrane polarity, using the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene and 6-dodecanoyl-N,N-dimethyl-2-naphthylamine, respectively. The CO2(liquid)/water(liquid) and the CO2(supercritical)/water(liquid) two-phase (heterogeneous) systems resulted in the formation of vesicles with high yield (ca. 85%-88%). The membrane fluidity and polarity of the vesicles were similar to those of liposomes prepared by the conventional method. It is suggested that high-pressure CO2 can be used to form an appropriate hydrophobic-hydrophilic interface where phospholipid molecules as a self-assembled membrane.

  6. Comparison between the ESFT method and LBL method of CO2 retrieval for high-resolution satellite

    Science.gov (United States)

    Li, Yanfen; Zhang, Chunmin; Wang, Dingyi; Chen, Jie; Liu, Dongdong; Rong, Piao

    2015-02-01

    The spectra of O2 A-band (0.76 μm) and CO2 near-infrared emissions (1.6 μm) for Medium-resolution Satellite (SCIAMACHY) are simulated by the SCIATRAN model (V3.1.29), and compared with the ESFT and LBL method, as the inversion accuracy and time consuming. The time consuming of LBL was more than ESFT with the relative error less than 1%, especially for the CO2 band. But for the CO2 (2.0 um) of High-resolution Satellite, the opposite result was found. That is to say, the LBL method was more suitable for High-resolution Satellite. Different wavelength intervals and integral wavelength steps are applied to the LBL to select the most appropriate combination for High-resolution SatelliteO2 A-band (0.76 μm) and CO2 near-infrared band (1.58 μm).

  7. Pillar[5]arene-based supramolecular organic frameworks for highly selective CO2-capture at ambient conditions.

    Science.gov (United States)

    Tan, Li-Li; Li, Haiwei; Tao, Yanchun; Zhang, Sean Xiao-An; Wang, Bo; Yang, Ying-Wei

    2014-11-05

    Low-density, solid-state, porous supramolecular organic frameworks are constructed using pillarenes. The frameworks have a honeycomb-like structure, permanent porosity, high thermal stability, and selective and reversible sorption properties toward CO2. The exceptionally selective CO2-sorption properties (375/1, 339/1) of one framework over N2 and CH4 indicate potential applications in CO2-capture for post-combustion power plants and natural gas sweetening. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Constraining the H2O and CO2 Contents of Basaltic Arc Magmas from Melt Inclusions: Diffusive H Loss and Shrinkage Bubble Formation, and Implications for the CO2 Contents of Primary Melts

    Science.gov (United States)

    Wallace, P. J.; Walowski, K. J.; Aster, E. M.

    2016-12-01

    The volatiles H2O and CO2 play a major role in arc magmatism, and tracking their return flux from the subducted slab to the Earth's surface is important for understanding global geochemical cycles. Melt inclusions (MIs) are a commonly used tool for measuring the concentrations of volatiles in magmas. However, recent studies have shown that MIs are imperfect storage containers that can lose H by diffusion through the mineral host and CO2 due to formation of a vapor bubble in the inclusion. Here, we use data for MIs from primitive basaltic magmas in the Lassen region of the Cascade arc [1] to show how post-entrapment processes can be distinguished from magmatic variability. Using the highest measured H2O from MIs at each volcanic center, we use correlations of volatile and trace element ratios (H2O/Ce, Cl/Nb, Sr/Nd) to demonstrate that primary geochemical variability results from variable addition of a hydrous subduction component to the mantle wedge. However, volcanic centers in the Lassen region and at nearby Mt. Shasta with the highest Sr/Nd, and therefore largest amount of a subduction component, have low H2O/Ce, suggesting that MIs in the most H2O-rich magmas were affected by diffusive H loss after trapping. For CO2 in MIs, we correct for the loss of CO2 to a vapor bubble formed by post-entrapment crystallization and thermal contraction [2]. The results suggest minimum magmatic values of 1500-6000 ppm CO2, but these likely reflect the depths of stalling and crystallization in the crust rather than primary magma values. Our results are similar to estimates for other arc volcanoes that range up to 4000 ppm CO2 (Fuego [3]), 3800 ppm (Klyuchevskoy [4]) and 7000 ppm (Jorullo [2]). The highest of these values overlap with the estimate of 0.6 - 1.3 wt% CO2 in primary arc magmas inferred from arc volcano CO2 emissions [5]. [1] Walowski et al. 2016, EPSL; [2] Aster et al. 2016, JVGR; [3] Moore et al. 2015, Am. Min.; [4] Mironov et al. 2015, EPSL; [5] Wallace 2005, JVGR.

  9. High-resolution pCO2 reconstruction across the early Cenozoic greenhouse and late Cenozoic icehouse climates

    Science.gov (United States)

    Cui, Y.; Schubert, B.

    2016-12-01

    Historical data and ice core records provide the best-constrained data on global temperatures and atmospheric carbon dioxide concentrations (pCO2), which can be used to calculate short-term estimates of climate sensitivity. These data, however, may not be representative of longer timescales and represent a period of Earth history when pCO2 and global temperatures were relatively low; recent work suggests that climate sensitivity may change under different climate states and timescales. Here we present a new high-resolution pCO2 reconstruction for the early (65 to 50 Ma) and late (30 to 0 Ma) Cenozoic using a proxy based on changes in carbon isotope fractionation in C3 land plants. This work uses widely available carbon isotope data from various terrestrial organic substrates to produce a nearly continuous record of pCO2. This record identifies both large-scale trends (e.g., the early Cenozoic is characterized by higher pCO2 than the late Cenozoic), as well as transient, highly elevated pCO2 during the early Eocene hyperthermals. We discuss the uncertainties associated with this new pCO2 reconstruction, which include the effects of precipitation, plant community shifts, and source effects on the δ13C record. Additionally, uncertainty associated with the correlation in time between δ13C estimates of atmospheric CO2 and the terrestrial δ13C of organic matter is included in the error propagation. Comparison of the new pCO2 record to existing global average temperature records based on the δ18O value of well-preserved marine foraminifera can yield new insight into Earth system climate sensitivity across a wide range of climate states and timescales.

  10. Ectomycorrhizal fungi and past high CO2 atmospheres enhance mineral weathering through increased below-ground carbon-energy fluxes.

    Science.gov (United States)

    Quirk, Joe; Andrews, Megan Y; Leake, Jonathan R; Banwart, Steve A; Beerling, David J

    2014-07-01

    Field studies indicate an intensification of mineral weathering with advancement from arbuscular mycorrhizal (AM) to later-evolving ectomycorrhizal (EM) fungal partners of gymnosperm and angiosperm trees. We test the hypothesis that this intensification is driven by increasing photosynthate carbon allocation to mycorrhizal mycelial networks using 14CO2-tracer experiments with representative tree–fungus mycorrhizal partnerships. Trees were grown in either a simulated past CO2 atmosphere (1500 ppm)—under which EM fungi evolved—or near-current CO2 (450 ppm). We report a direct linkage between photosynthate-energy fluxes from trees to EM and AM mycorrhizal mycelium and rates of calcium silicate weathering. Calcium dissolution rates halved for both AM and EM trees as CO2 fell from 1500 to 450 ppm, but silicate weathering by AM trees at high CO2 approached rates for EM trees at near-current CO2. Our findings provide mechanistic insights into the involvement of EM-associating forest trees in strengthening biological feedbacks on the geochemical carbon cycle that regulate atmospheric CO2 over millions of years.

  11. Improvement of dermatochalasis and periorbital rhytides with a high-energy pulsed CO2 laser: a retrospective study.

    Science.gov (United States)

    Alster, Tina S; Bellew, Supriya G

    2004-04-01

    Upper eyelid dermatochalasis is typically treated with excisional blepharoplasty. The role of the CO2 laser previously had been confined to that of a vaporizing, incisional, or hemostatic tool. Over the past several years, however, ablative CO2 laser skin resurfacing has been popularized as an adjunctive treatment to blepharoplasty to minimize periorbital rhytides through its vaporizing as well as skin-tightening action. To evaluate the safety and efficacy of a high-energy pulsed CO2 laser as a stand-alone treatment for dermatochalasis and periorbital rhytides. Sixty-seven patients (skin phototypes I-IV) with mild-to-severe upper eyelid dermatochalasis and periorbital rhytides received periocular CO2 laser skin treatment. Global assessment scores of dermatochalasis and rhytides were determined by a side-by-side comparison of periocular photographs preoperatively and 1, 3, and 6 months postoperatively. In addition, caliper measurements of upper eyelids before and 1, 3, and 6 months after treatment were obtained. Both dermatochalasis and periorbital rhytides were significantly improved after periocular CO2 laser skin resurfacing. Patients with more severe dermatochalasis and rhytides showed greater improvement after CO2 laser treatment than did those with mild or moderate involvement. Side effects were limited to erythema and transient hyperpigmentation. No scarring, hypopigmentation, or ectropion were observed. Periocular skin resurfacing with a CO2 laser can safely and effectively improve upper eyelid dermatochalasis and periorbital rhytides.

  12. Chlorophyll content of spring wheat flag leaves grown under elevated CO2 concentrations and other environmental stresses within the 'ESPACE-wheat' project

    NARCIS (Netherlands)

    Ommen, O.E.; Donnelly, A.; Vanhoutvin, S.; Oijen, van M.; Manderscheid, R.

    1999-01-01

    Spring wheat cv. Minaret was grown in open-top chambers at four sites across Europe. The effect of different treatments (CO2 enrichment, O3 fumigation, drought stress and temperature) on the chlorophyll content of the flag leaf was investigated using the MINOLTA SPAD-502 meter. Under optimum growth

  13. Physiological and genetic control mechanisms for plant adaptation to high temperature and elevated CO2

    Energy Technology Data Exchange (ETDEWEB)

    Zeiger, Eduardo

    2001-02-01

    Acclimations of the stomatal response to CO2 were characterized. Stomata from the model plant used, Vicia faba, are very sensitive to ambient CO2 when grown in growth chambers as compared to stomata from green house grown leaves. The different CO2 sensitivities of growth chamber and green house grown guard cells was confirmed by reciprocal transfer experiments. Stomata acclimated to their new environment and acquired the CO2 sensitivity typical of that environment. A mechanism for CO2 sensing was also characterized. Results show that CO2 concentration alters the concentration of zeaxanthin in the guard cell chloroplast, thus modifying the light response of the guard cells. This mechanism accounts for the well characterized interactions of light and CO2 in the stomatal responses. The xanthophyll cycle in the stomata of the facultative CAM plant, Mesembryanthemum crystallinum, was characterized. In the C3 mode, zeaxanthin is formed in the light and stomata open. Upon induction of the CAM mode, zeaxanthin synthesis is blocked and stomata no longer respond to light. These results implicate the regulation of the xanthophyll cycle of guard cells in the CAM adaptation.

  14. Aquaporin plays an important role in mediating chloroplastic CO2 concentration under high-N supply in rice (Oryza sativa) plants.

    Science.gov (United States)

    Ding, Lei; Gao, Limin; Liu, Wei; Wang, Min; Gu, Mian; Ren, Binbin; Xu, Guohua; Shen, Qirong; Guo, Shiwei

    2015-09-18

    Our previous studies demonstrated that chloroplastic CO2 concentration (Cc) is not sufficient under high-nitrogen (N) supply in rice plants. In this research, we studied how aquaporins- (AQPs) mediated Cc under different N-supply levels. A hydroponic experiment was conducted in a greenhouse with three different N levels (low N, 0.71 mM; intermediate N, 2.86 mM; and high N, 7.14 mM) in a rice cultivar (Oryza sativa cv. Shanyou 63) and with an ospip1;1 mutant (Oryza sativa cv. Nipponbare). The photosynthetic nitrogen-use efficiency (PNUE) decreased with increasing leaf-N content. Under high-N supply, the estimated Cc was significantly lower than the theoretical Cc and the specific Rubisco activity (carboxylation efficiency/Rubisco content, CE/Rubisco) decreased, because of a decrease of relative CO2 diffusion conductance (total CO2 diffusion conductance/leaf-N content, gt /N) in mesophyll cells. Real Time Quantitative PCR (Q-RT-PCR) showed that most OsPIP1s and OsPIP2s expression were downregulated under the high-N supply. Furthermore, Cc and gm decreased in the ospip1;1 mutant line compared with that of the wild-type plant. It was concluded that under high-N supply, the decreased PNUE was associated with non-sufficient Cc, mediated by AQP in mesophyll conductance. © 2015 Scandinavian Plant Physiology Society.

  15. 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

  16. 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.

  17. Methylcellulose-Directed Synthesis of Nanocrystalline Zeolite NaA with High CO2 Uptake

    Directory of Open Access Journals (Sweden)

    Dilshod Shakarova

    2014-07-01

    Full Text Available Zeolite NaA nanocrystals with a narrow particle size distribution were prepared by template-free hydrothermal synthesis in thermo-reversible methylcellulose gels. The effects of the amount of methylcellulose, crystallization time and hydrothermal treatment temperature on the crystallinity and particle size distribution of the zeolite NaA nanocrystals were investigated. We found that the thermogelation of methylcellulose in the alkaline Na2O-SiO2-Al2O3-H2O system played an important role in controlling the particle size. The synthesized zeolite nanocrystals are highly crystalline, as demonstrated by X-ray diffraction (XRD, and scanning electron microscopy (SEM shows that the nanocrystals can also display a well-defined facetted morphology. Gas adsorption studies on the synthesized nanocrystalline zeolite NaA showed that nanocrystals with a size of 100 nm displayed a high CO2 uptake capacity (4.9 mmol/g at 293 K at 100 kPa and a relatively rapid uptake rate compared to commercially available, micron-sized particles. Low-cost nanosized zeolite adsorbents with a high and rapid uptake are important for large scale gas separation processes, e.g., carbon capture from flue gas.

  18. CO2 and H2O Contents of Melt Inclusions from the 1891 Basaltic Balloon Eruption of Foerstner Submarine Volcano, Italy

    Science.gov (United States)

    Balcanoff, J. R.; Carey, S.; Kelley, K. A.; Boesenberg, J. S.

    2016-12-01

    Eruptions that produce basaltic balloon products are an uncommon eruption style only observed in five cases during historical times. Basaltic balloon products form in gas rich shallow submarine eruptions, which produce large hollow clasts with sufficient buoyancy to float on seawater. Foerstner submarine volcano, off the coast of Pantelleria (Italy), erupted with this style in 1891 and is the only eruption where the vent site (250 m water depth) has been studied and sampled in detail with remotely operated vehicles (ROVs). Here, we report Fournier Transform Infrared Spectroscopy (FTIR) and electron microprobe (EMP) analyses of major elements and dissolved volatiles in melt inclusions from olivine and plagioclase phenocrysts picked from highly vesicular clasts recovered from the seafloor. The trachybasaltic melt is enriched in alkalis with notably high phosphorus (1.82-2.38 wt%), and melt inclusions show elevated H2O concentrations of 0.17 to 1.2 wt.% and highly elevated CO2 concentrations of 928 to 1864 ppm. Coexisting matrix glass is completely degassed with respect to carbon dioxide but has variable water contents up to 0.19 %. The maximum carbon dioxide value implies saturation at 1.5 kb, or 4.5 km below the volcano. Trends in the CO2 and H2O data are most compatible with calculated open system degassing behavior. This is consistent with a proposed balloon formation mechanism involving a hybrid strombolian eruption style with the potential accumulation of gas-rich pockets below the vent as gas bubbles moved upwards independent of the low viscosity basaltic melt. Discharge of the gas-rich pockets led to the discharge of meter-sized slugs of magma with large internal vesicles (several tens of centimeters). A subset of these clasts had bulk densities that were lower than seawater, allowing them to rise to the sea surface where they either exploded or became water saturated and sank back to the seafloor.

  19. Safety and efficacy of high fluence CO2 laser skin resurfacing with a single pass.

    Science.gov (United States)

    Khosh, M M; Larrabee, W F; Smoller, B

    1999-01-01

    Carbon dioxide (CO2) laser skin resurfacing has nearly replaced more traditional methods of superficial skin rejuvenation. Post-treatment erythema is the most common side effect of this method of skin resurfacing. Sublethal thermal damage to the dermis has been proposed as an etiology for post laser erythema. Recent developments in laser resurfacing technology have aimed at minimizing thermal damage to the dermis. To determine depth of skin ablation, extent of thermal injury, and ideal laser parameters for the FeatherTouch laser system. To assess the safety and efficacy of laser resurfacing at high energy fluences with a single pass. Laser resurfacing was performed in the preauricular skin of five patients undergoing rhytidectomy. A total of 60 sites were tested with fluences of 7 to 17 Joules/cm2. Histologic evaluation of excised skin showed maximal thermal injury to be restricted to 60 microns in the papillary dermis. The reticular dermis showed no evidence of injury. Based on these findings, laser resurfacing at 17 J/cm2 (70 watts) was performed on 30 patients (in the periorbital area, a maximum of 9 J/cm2 or 36 watts was used). Follow up ranged between 12 and 18 months. Based on histologic comparison of average and high fluence laser resurfacing, high fluence laser resurfacing did not cause added thermal damage to the reticular dermis. In the clinical group, no major complications such as scarring, scleral show, infection or ectropion were encountered. Transient hyperpigmentation was noted in three patients. Overall patient satisfaction was good to excellent. Post-treatment erythema lasted an average of 4 weeks. We conclude that CO2 laser resurfacing of the face (excluding the periorbital region) can be performed safely and effectively, with the FeatherTouch laser, at 17 J/cm2 with one pass. In our group of patients, laser resurfacing with a single pass at 17 J/cm2 caused less post-operative erythema than two or more passes at 9 J/cm2.

  20. HIGH POWER, HELIUM-FREE, SUPERATMOSPHERIC CO2, MINI-TEA LASER

    OpenAIRE

    Marchetti, S.; Simili, R.; Giorgi, M.

    1987-01-01

    Large Helium -free emissions are obtained in two mini-TEA CO2 lasers , by using always a corona preionization, without additives, with a maximum energy density of 900 J/lt. deposited into the discharge

  1. 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 CO2 (currently ~400 μatm) is driving climate change and causing acidification of both marine and freshwater environments. Physiologists have long known that CO2 directly affects acid-base and ion regulation, respiratory function and aerobic performance in aquatic animals. More recently, many studies have demonstrated that elevated CO2 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 CO2 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' CO2 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 CO2 levels; or 4) the breeding of species within intensive aquaculture having further selected traits that confer tolerance to elevated CO2 . 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 CO2 on future aquatic ecosystems and the sustainability of fish and shellfish aquaculture.

  2. Highly accurate intensity factors of pure CO2 lines near 2 μ m

    Science.gov (United States)

    Odintsova, T. A.; Fasci, E.; Moretti, L.; Zak, E. J.; Polyansky, O. L.; Tennyson, J.; Gianfrani, L.; Castrillo, A.

    2017-06-01

    Line intensities for carbon dioxide are measured with a novel spectroscopic approach, assisted by an optical frequency comb synthesizer for frequency calibration purposes. The main feature of the spectrometer consists in the exploitation of optical feedback from a V-shaped high-finesse optical resonator to effectively narrow a distributed feedback diode laser at the wavelength of 2 μ m. Laser-gas interaction takes place inside an isothermal cell, which is placed on the transmission from the cavity. High quality, self-calibrated, absorption spectra are observed in pure CO2 samples at different gas pressures, in coincidence with three lines of the R-branch of the ν1 + 2ν2 + ν3 band. Line intensities are determined using a global fitting approach in which a manifold of spectra are simultaneously analyzed across the range of pressures between 5 and 100 Torr, sharing a restricted number of unknown parameters. Various sources of uncertainty have been identified and carefully quantified, thus leading to an overall uncertainty ranging between 0.17% and 0.23%. The measured values are in a very good agreement with recent ab initio predictions.

  3. Feasibility study of a space-based high pulse energy 2  μm CO2 IPDA lidar.

    Science.gov (United States)

    Singh, Upendra N; Refaat, Tamer F; Ismail, Syed; Davis, Kenneth J; Kawa, Stephan R; Menzies, Robert T; Petros, Mulugeta

    2017-08-10

    Sustained high-quality column carbon dioxide (CO2) atmospheric measurements from space are required to improve estimates of regional and continental-scale sources and sinks of CO2. Modeling of a space-based 2 μm, high pulse energy, triple-pulse, direct detection integrated path differential absorption (IPDA) lidar was conducted to demonstrate CO2 measurement capability and to evaluate random and systematic errors. Parameters based on recent technology developments in the 2 μm laser and state-of-the-art HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) detection system were incorporated in this model. Strong absorption features of CO2 in the 2 μm region, which allows optimum lower tropospheric and near surface measurements, were used to project simultaneous measurements using two independent altitude-dependent weighting functions with the triple-pulse IPDA. Analysis of measurements over a variety of atmospheric and aerosol models using a variety of Earth's surface target and aerosol loading conditions were conducted. Water vapor (H2O) influences on CO2 measurements were assessed, including molecular interference, dry-air estimate, and line broadening. Projected performance shows a measurements related to column CO2 optical depth for the space-based IPDA using 10 s signal averaging over the Railroad Valley (RRV) reference surface under clear and thin cloud conditions.

  4. Shellfish face uncertain future in high CO2 world: influence of acidification on oyster larvae calcification and growth in estuaries.

    Directory of Open Access Journals (Sweden)

    A Whitman Miller

    Full Text Available BACKGROUND: Human activities have increased atmospheric concentrations of carbon dioxide by 36% during the past 200 years. One third of all anthropogenic CO(2 has been absorbed by the oceans, reducing pH by about 0.1 of a unit and significantly altering their carbonate chemistry. There is widespread concern that these changes are altering marine habitats severely, but little or no attention has been given to the biota of estuarine and coastal settings, ecosystems that are less pH buffered because of naturally reduced alkalinity. METHODOLOGY/PRINCIPAL FINDINGS: To address CO(2-induced changes to estuarine calcification, veliger larvae of two oyster species, the Eastern oyster (Crassostrea virginica, and the Suminoe oyster (Crassostrea ariakensis were grown in estuarine water under four pCO(2 regimes, 280, 380, 560 and 800 microatm, to simulate atmospheric conditions in the pre-industrial era, present, and projected future concentrations in 50 and 100 years respectively. CO(2 manipulations were made using an automated negative feedback control system that allowed continuous and precise control over the pCO(2 in experimental aquaria. Larval growth was measured using image analysis, and calcification was measured by chemical analysis of calcium in their shells. C. virginica experienced a 16% decrease in shell area and a 42% reduction in calcium content when pre-industrial and end of 21(st century pCO(2 treatments were compared. C. ariakensis showed no change to either growth or calcification. Both species demonstrated net calcification and growth, even when aragonite was undersaturated, a result that runs counter to previous expectations for invertebrate larvae that produce aragonite shells. CONCLUSIONS AND SIGNIFICANCE: Our results suggest that temperate estuarine and coastal ecosystems are vulnerable to the expected changes in water chemistry due to elevated atmospheric CO(2 and that biological responses to acidification, especially calcifying

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

    Science.gov (United States)

    Laruelle, Goulven G.; Landschützer, Peter; Gruber, Nicolas; Tison, Jean-Louis; Delille, Bruno; Regnier, Pierre

    2017-10-01

    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 temperature

  6. 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

  7. Effects of elevated CO2 on grapevine (Vitis vinifera L.): volatile composition, phenolic content, and in vitro antioxidant activity of red wine.

    Science.gov (United States)

    Gonçalves, Berta; Falco, Virgílio; Moutinho-Pereira, José; Bacelar, Eunice; Peixoto, Francisco; Correia, Carlos

    2009-01-14

    The impact of elevated carbon dioxide concentration ([CO2]) on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro, was investigated during 2005 and 2006. Grapevines were grown either in open-top chambers (OTC) with ambient (365 +/- 10 ppm) or elevated (500 +/-16 ppm) [CO2] or in an outside plot. In general, the increase of [CO2] did not affect berry characteristics, especially the total anthocyan and tannin concentrations. However, the total anthocyan and polyphenol concentrations of the red wine were inhibited under elevated [CO2]. The antioxidant capacity of the wines was determined by DPPH, ABTS, and TBARS assays and, despite the low concentrations of phenolics, the elevated [CO2] did not significantly change the total antioxidant capacity of the red wines. Thirty-five volatile compounds belonging to seven chemical groups were identified: C6 alcohols, higher alcohols, esters, terpenols, carbonyl compounds, acids, volatile phenols, and C13 norisoprenoids. Generally, the same volatile compounds were present in all of the wines, but the relative levels varied among the treatments. The effect of elevated [CO2] was significant because it was detected as an increase in ethyl 2-methylbutyrate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, butyric acid, and isovaleric acid concentrations and a decrease in ethyl acetate concentration when compared to wines produced in ambient [CO2] in 2005. In elevated [CO2], wines from 2006 had lower methionol, 1-octanol, and 4-ethylguaiacol and higher ethyl lactate and linalool concentrations. The increase in [CO2] did not significantly affect C6 alcohols, citronellol, carbonyl compounds, and beta-damascenone concentrations. This study showed that the predicted rise in [CO2] did not produce negative

  8. Interacting ZnCo2O4 and Au nanodots on carbon nanotubes as highly efficient water oxidation electrocatalyst

    Science.gov (United States)

    Cheng, Hui; Su, Chang-Yuan; Tan, Zhi-Yun; Tai, Su-Zhen; Liu, Zhao-Qing

    2017-07-01

    An advanced hybrid electrocatalyst consisting of ZnCo2O4 nanodots and Au decorated carbon nanotubes is developed for oxygen evolution reaction (OER). In the catalyst system, carbon nanotubes are served as the support substrate to enhance the conductivity of ZnCo2O4 and provide a high specific area; meanwhile, Au species accelerate the electron-stripping from cobalt ions during the catalytic process, leading to a fast promotion of cobalt ions with high valence state which possess a highly electrocatalytic efficiency. With the well synergistic effect between the components, ZnCo2O4/Au/CNTs exhibits low potential of 1.67 V at j = 10 mA cm-2, large current density of 97.8 mA cm-2 at high operating potential (1.8 V), and prominent durability in alkaline. This finding will pave a new avenue to search highly efficient and stable electrocatalysts for water splitting devices.

  9. Blunt-Body Aerothermodynamic Database from High-Enthalpy CO2 Testing in an Expansion Tunnel

    Science.gov (United States)

    Hollis, Brian R.; Prabhu, Dinesh K.; Maclean, Matthew; Dufrene, Aaron

    2016-01-01

    An extensive database of heating, pressure, and flow field measurements on a 70-deg sphere-cone blunt body geometry in high-enthalpy, CO2 flow has been generated through testing in an expansion tunnel. This database is intended to support development and validation of computational tools and methods to be employed in the design of future Mars missions. The test was conducted in an expansion tunnel in order to avoid uncertainties in the definition of free stream conditions noted in previous studies performed in reflected shock tunnels. Data were obtained across a wide range of test velocity/density conditions that produced various physical phenomena of interest, including laminar and transitional/turbulent boundary layers, non-reacting to completely dissociated post-shock gas composition and shock-layer radiation. Flow field computations were performed at the test conditions and comparisons were made with the experimental data. Based on these comparisons, it is recommended that computational uncertainties on surface heating and pressure, for laminar, reacting-gas environments can be reduced to +/-10% and +/-5%, respectively. However, for flows with turbulence and shock-layer radiation, there were not sufficient validation-quality data obtained in this study to make any conclusions with respect to uncertainties, which highlights the need for further research in these areas.

  10. Transformation of hydroxyapatite to fluorapatite by irradiation with high-energy CO2 laser.

    Science.gov (United States)

    Meurman, J H; Hemmerlé, J; Voegel, J C; Rauhamaa-Mäkinen, R; Luomanen, M

    1997-01-01

    High-energy laser irradiation has been shown to cause crystalline transformations in apatites, which may lead to the formation of tricalcium phosphates with a resulting decrease in acid resistance. Depending on the nature and energy density of laser irradiation used, however, an increase of acid resistance of dental enamel has also been reported after laser irradiation. The aim of the present study was to investigate the phase transformation of hydroxyapatite (HA) to fluorapatite (FA) in a model system that incorporates sodium fluoride (NaF) into apatite structure by using laser irradiation. A CO2 laser was used at energy densities ranging from 21 to 500 J/cm2. Synthetic HA mixed with NaF (10:1) was the target of laser irradiation. The crystalline structures were then investigated using X-ray diffraction analysis. The results showed that a phase transformation of HA to FA could be realized, and that the threshold energy density needed was 38 J/cm2. Not only is the finding crystallographically important, but it also opens new perspectives for future research regarding the development of laser technology for clinical purposes.

  11. 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.......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 most widely used applications of these systems is given and the potential advantages of the energy enhancer are discussed.The basic principle behind the energy enhancing technique is explained and two new energy enhancers are presented and evaluated. The first one is designed especially for single text...

  12. Stability information in plasma image of high-power CO 2 laser welding

    Science.gov (United States)

    Li, Guohua; Cai, Yan; Wu, Yixiong

    2009-09-01

    In deep penetration laser welding, a capillary called keyhole is formed when the energy intensity reaches 10 6 W/cm 2. During this process, the vaporized metal and the surrounding atmosphere can be ionized to form plasma both in and above the keyhole. The stability of the keyhole has an important influence on the properties of welded components and the fluctuations of plasma. In this paper, a method was developed to acquire the stability information from plasma images taken by high-speed photography. The influences of surface impurity and the flowrate of side-assist gas on the stability were investigated. Bead-on-plate welding was performed on 12 mm E-grade shipbuilding steel plates using a 15 kW CO 2 laser, with helium as the blowing gas. Three characteristic parameters were used to evaluate the stability. It was found that these three characteristic parameters can effectively indicate the stability variation caused by the surface impurity and gas flowrate. The present research provides important insights into developing image-based sensors to monitor the welding process.

  13. An efficient system for carbonation of high-rate algae pond water to enhance CO2 mass transfer.

    Science.gov (United States)

    Putt, Ron; Singh, Manjinder; Chinnasamy, Senthil; Das, K C

    2011-02-01

    High-rate algal ponds have the potential to produce 59 T of dry biomass ha(-1)year(-1) based on the specific productivity of 20 g m(-2) day(-1). Atmospheric air provides only 5% of the CO(2) to the pond surface required for photosynthesis. Hence, CO(2) is usually provided via bubbling of concentrated CO(2)-air mixture into the algae ponds. This process is, however, not significantly effective in terms of mass transfer. Use of bubble column to increase the interfacial area of contact available for gas exchange is proposed as an efficient alternative. A carbonation column (CC) was modeled and designed to measure CO(2) absorptivity in-pond water at various pH regimes. The CC performed at 83% CO(2) transfer efficiency. An air-to-pond mass transport coefficient of 0.0037 m min(-1) was derived. The proposed device can be used with any exhaust gas stream with higher concentrations of CO(2) in conjunction with raceways for optimizing algae production. Published by Elsevier Ltd.

  14. 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

  15. Process control in continuous high-power CO2 laser beam welding

    Science.gov (United States)

    Seidel, Bernd; Beersiek, Jorg; Beyer, Eckhard

    1994-09-01

    The use of high power CO2 lasers in welding enables processing with high laser intensities at the workpiece which is connected with the formation of a laser induced plasma at the surface of the workpiece. Therefore the effect of deep penetration welding by formation of a plasma filled keyhole and plasma plume above the workpiece is possible, including the risk of plasma shielding, which means strong absorption of the incident laser beam above the workpiece and thus interruption of the welding process. The conditions for ignition of plasma shielding, which is determined by electron density, are mainly influenced by laser intensity, process gas and material. Variations of these parameters have been conducted in order to find limits for the appearance of plasma shielding. Experimental data are used to verify a model concerning the absorption mechanism of a stationary shielding plasma state. The dynamic behavior is treated by time resolved spectroscopic analysis of the light emitted by the plasma above the workpiece yielding monitoring signals that have a strong correlation with the formation of plasma shielding. Based on these investigations a closed-loop process control in continuous high power laser welding has been developed. Using the intensity of a spectral line of laser induced plasma as monitoring signal and the regulation of laser intensity via laser power, plasma shielding can be suppressed. From the industrial point of view increase in economy and reliability of the laser welding process combined with quality improvements which are induced by the application of the plasma shielding controller (PSC) are of great importance. For this reason three examples of PSC application are presented.

  16. 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.

  17. 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

  18. Metabolically active microbial communities in marine sediment under high-CO(2) and low-pH extremes.

    Science.gov (United States)

    Yanagawa, Katsunori; Morono, Yuki; de Beer, Dirk; Haeckel, Matthias; Sunamura, Michinari; Futagami, Taiki; Hoshino, Tatsuhiko; Terada, Takeshi; Nakamura, Ko-Ichi; Urabe, Tetsuro; Rehder, Gregor; Boetius, Antje; Inagaki, Fumio

    2013-03-01

    Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO(2) in the seabed. The emission of CO(2) may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO(2) and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO(2)-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO(2) concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO(2) concentration, indicating that microbial activity and community structure are sensitive to CO(2) venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13-30 cm in depth) characterized by high CO(2). Measurement of the potential sulfate reduction rate at pH conditions of 3-9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO(2)-seep sedimentary environment; however

  19. Metabolically active microbial communities in marine sediment under high-CO2 and low-pH extremes

    Science.gov (United States)

    Yanagawa, Katsunori; Morono, Yuki; de Beer, Dirk; Haeckel, Matthias; Sunamura, Michinari; Futagami, Taiki; Hoshino, Tatsuhiko; Terada, Takeshi; Nakamura, Ko-ichi; Urabe, Tetsuro; Rehder, Gregor; Boetius, Antje; Inagaki, Fumio

    2013-01-01

    Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO2 in the seabed. The emission of CO2 may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO2 and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO2-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO2 concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO2 concentration, indicating that microbial activity and community structure are sensitive to CO2 venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13–30 cm in depth) characterized by high CO2. Measurement of the potential sulfate reduction rate at pH conditions of 3–9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO2-seep sedimentary environment; however, CO2 and p

  20. High CO2 enhances the competitive strength of seaweeds over corals

    Science.gov (United States)

    Diaz-Pulido, Guillermo; Gouezo, Marine; Tilbrook, Bronte; Dove, Sophie; Anthony, Kenneth R N

    2011-01-01

    Space competition between corals and seaweeds is an important ecological process underlying coral-reef dynamics. Processes promoting seaweed growth and survival, such as herbivore overfishing and eutrophication, can lead to local reef degradation. Here, we present the case that increasing concentrations of atmospheric CO2 may be an additional process driving a shift from corals to seaweeds on reefs. Coral (Acropora intermedia) mortality in contact with a common coral-reef seaweed (Lobophora papenfussii) increased two- to threefold between background CO2 (400 ppm) and highest level projected for late 21st century (1140 ppm). The strong interaction between CO2 and seaweeds on coral mortality was most likely attributable to a chemical competitive mechanism, as control corals with algal mimics showed no mortality. Our results suggest that coral (Acropora) reefs may become increasingly susceptible to seaweed proliferation under ocean acidification, and processes regulating algal abundance (e.g. herbivory) will play an increasingly important role in maintaining coral abundance. PMID:21155961

  1. High-Throughput Synthesis of Mixed-Metal Electrocatalysts for CO2 Reduction.

    Science.gov (United States)

    He, Jingfu; Dettelbach, Kevan E; Salvatore, Danielle A; Li, Tengfei; Berlinguette, Curtis P

    2017-05-22

    The utilization of CO2 as a feedstock requires fundamental breakthroughs in catalyst design. The efficiencies and activities of pure metal electrodes towards the CO2 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 CO2 catalyst compositions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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.

  3. 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.

  4. Polydopamine-based synthesis of a zeolite imidazolate framework ZIF-100 membrane with high H2/CO2 selectivity

    OpenAIRE

    Wang, Nanyi; Liu, Yi; Qiao, Zhiwei; Diestel, Lisa; Zhou, Jian; Huang, Aisheng; Caro, Jürgen

    2015-01-01

    A highly permselective ZIF-100 molecular sieve membrane has been prepared on a polydopamine (PDA)-modified support. Attributed to the formation of strong covalent and non-covalent bonds between PDA and ZIF-100, the ZIF-100 nutrients are attracted and bound to the support surface, thus promoting the growth of well-intergrown and phase-pure ZIF-100 membranes. The developed ZIF-100 membranes show high H2/CO2 selectivity due to the outstanding CO2 adsorption capacity of ZIF-100.

  5. highly selective amino acid salt solutions as absorption liquid for CO(2) capture in gas-liquid membrane contactors.

    Science.gov (United States)

    Simons, Katja; Nijmeijer, Kitty; Mengers, Harro; Brilman, Wim; Wessling, Matthias

    2010-08-23

    The strong anthropogenic increase in the emission of CO(2) and the related environmental impact force the developments towards sustainability and carbon capture and storage (CCS). In the present work, we combine the high product yields and selectivities of CO(2) absorption processes with the advantages of membrane technology in a membrane contactor for the separation of CO(2) from CH(4) using amino acid salt solutions as competitive absorption liquid to alkanol amine solutions. Amino acids, such as sarcosine, have the same functionality as alkanol amines (e.g., monoethanolamine=MEA), but in contrast, they exhibit a better oxidative stability and resistance to degradation. In addition, they can be made nonvolatile by adding a salt functionality, which significantly reduces the liquid loss due to evaporation at elevated temperatures in the desorber. Membrane contactor experiments using CO(2)/CH(4) feed mixtures to evaluate the overall process performance, including a full absorption/desorption cycle show that even without a temperature difference between absorber and desorber, a CO(2)/CH(4) selectivity of over 70 can be easily achieved with the sarcosine salt solution as absorption liquid. This selectivity reaches values of 120 at a temperature difference between absorber and desorber of 35 degrees C, compared to a value of only 60 for MEA under the same conditions. Although CO(2) permeance values are somewhat lower than the values obtained for MEA, the results clearly show the potential of amino acid salt solutions as competitive absorption liquids for the energy efficient removal of CO(2). In addition, due to the low absorption of CH(4) in sarcosine compared to MEA, the loss of CH(4) is reduced and significantly higher CH(4) product yields can be obtained.

  6. 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.

  7. Metal–organic framework based mixed matrix membranes : A solution for highly efficient CO2 capture?

    NARCIS (Netherlands)

    Seoane, B.; Coronas, J.; Gascon, I.; Benavides, M.E.; Karvan, O.; Caro, J.; Kapteijn, F.; Gascon, J.

    2015-01-01

    The field of metal–organic framework based mixed matrix membranes (M4s) is critically reviewed, with special emphasis on their application in CO2 capture during energy generation. After introducing the most relevant parameters affecting membrane performance, we define targets in terms of selectivity

  8. Adsorptive separation of CO2/CH4/CO gas mixtures at high pressures

    NARCIS (Netherlands)

    Krishna, R.

    2012-01-01

    The major objective of this communication is to compare the performance of three metal-organic frameworks (MOFs): CuBTC, MIL-101, and Zn(bdc)dabco, with that of NaX zeolite for selective adsorption of CO2 from mixtures containing CH4 and CO in a pressure swing adsorption (PSA) unit operating at

  9. 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

  10. High prevalence of diffusive uptake of CO2 by macroalgae in a temperate subtidal ecosystem.

    Science.gov (United States)

    Cornwall, Christopher E; Revill, Andrew T; Hurd, Catriona L

    2015-05-01

    Productivity of most macroalgae is not currently considered limited by dissolved inorganic carbon (DIC), as the majority of species have CO2-concentrating mechanisms (CCM) allowing the active uptake of DIC. The alternative, diffusive uptake of CO2 (non-CCM), is considered rare (0-9% of all macroalgal cover in a given ecosystem), and identifying species without CCMs is important in understanding factors controlling inorganic carbon use by eukaryotic algae. CCM activity has higher energetic requirements than diffusive CO2 uptake, therefore when light is low, CCM activity is reduced in favour of diffusive CO2 uptake. We hypothesized that the proportional cover of macroalgae without CCMs (red and green macroalgae) would be low (green macroalgae (two species). The proportion of non-CCM species increased with depth at three of four sites. 35% of species tested had significantly depleted δ(13)C values at deeper depths. Non-CCM macroalgae are more abundant in some temperate reefs than previously thought. If ocean acidification benefits non-CCM species, the ramifications for subtidal macroalgal assemblages could be larger than previously considered.

  11. The effects of high soil CO2 concentrations on leaf reflectance of maize plants

    NARCIS (Netherlands)

    Noomen, M.F.; Skidmore, A.K.

    2009-01-01

    Carbon dioxide gas at higher concentrations is known to kill vegetation and can also lead to asphyxiation in humans and animals. The objective of this study is to test whether soil CO2 concentrations ranging from 2% to 50% can be detected using vegetative spectral reflectance. A greenhouse

  12. How do polymerized room-temperature ionic liquid membranes plasticize during high pressure CO2 permeation?

    NARCIS (Netherlands)

    Simons-Fischbein, K.; Nijmeijer, Dorothea C.; Bara, J.B.; Noble, R.D.; Wessling, Matthias

    2010-01-01

    Room-temperature ionic liquids (RTILs) are a class of organic solvents that have been explored as novel media for CO2 separations. Polymerized RTILs (poly(RTILs)) can be synthesized from RTIL monomers to form dense, solid gas selective membranes. It is of interest to understand the permeation

  13. 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

  14. Physiological basis for high CO2 tolerance in marine ectothermic animals: pre-adaptation through lifestyle and ontogeny?

    Science.gov (United States)

    Melzner, F.; Gutowska, M. A.; Langenbuch, M.; Dupont, S.; Lucassen, M.; Thorndyke, M. C.; Bleich, M.; Pörtner, H.-O.

    2009-10-01

    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 efficient compensation of

  15. Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2Adsorption Membrane.

    Science.gov (United States)

    Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

    2017-12-01

    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 CO 2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO 2 and 99% N 2 . 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 CO 2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO 2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO 2 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.

  16. Retrieval of Atmospheric CO2 and CH4 Variations Using Ground-Based High Resolution Fourier Transform Infrared Spectra

    Directory of Open Access Journals (Sweden)

    Tian Yuan

    2015-01-01

    Full Text Available High resolution Fourier transform near IR solar spectra are used to estimate the column-averaged dry-air mole fraction (DMF of CO2 and CH4 variations in the atmosphere. The preliminary retrieval results for CO2 and CH4 variations in the area of Hefei, China, are presented, and the underlying error sources are also analyzed. Both a forward analysis and an inversion algorithm are included in the retrieval. The forward analysis uses the modeled atmospheric transmittance to line-by-line (LBL convolute the instrument line shape function. The influences of the temperature, pressure, humidity, and a priori gases are considered in the atmospheric transmittance model. The inversion algorithm is based on the nonlinear iterative and nonlinear least squares spectral fitting, which is used to obtain VCDCO2 and VCDCH4 (which represent vertical column density of CO2 and CH4, resp.. Furthermore, the VCDO2 is also retrieved for converting the VCDs into DMFs. DMFs are final products of data analysis. The inversion results can clearly resolve the tiny variations of CO2 and CH4 under strong atmospheric background. Spectral fitting residuals for both VCDCO2 and VCDCH4 are less than 0.5%. Finally, CO2 and CH4 diurnal variations are investigated based on a typical observation. About 2 ppm amplitude for DMFCO2 diurnal variations and less than 15 ppb amplitude for DMFCH4 are observed.

  17. Swelling Behavior of High-Chromium, Vanadium-Bearing Titanomagnetite Pellets in H2-CO-CO2 Gas Mixtures

    Science.gov (United States)

    Li, F.; Chu, M. S.; Tang, J.; Liu, Z. G.; Feng, C.; Tang, Y. T.

    2017-10-01

    In this study, the effects of temperature, gas composition and reduction degree on the reduction swelling index (RSI) of high-chromium vanadium-bearing titanomagnetite (HCVT) pellets during reduction with H2-CO-CO2 gas mixtures are investigated. The results show that the formation of massive wüstite causes most of the volume expansion of the pellets. The swelling of HCVT pellets is intensified with the temperature and content of CO, and the RSI reaches a maximum at the reduction degree of 35-50%. In H2/CO = 5/2 (volume ratio) with a temperature range from 1223 K to 1373 K, the maximum RSI increases from 14.68% to 22.54%. Nevertheless, when the ratio of H2/CO increases from 2/5 to 5/2 at 1223 K, the maximum RSI of the pellets decreases from 21.25% to 19.55%. Meanwhile, the shrinking rate of the pellets also decreases from 33.20% to 27.26%.

  18. 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.

  19. 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.

  20. Differential regulation of dehydrin expression and trehalose levels in Cardinal table grape skin by low temperature and high CO2.

    Science.gov (United States)

    Navarro, Sara; Vazquez-Hernandez, María; Rosales, Raquel; Sanchez-Ballesta, María Teresa; Merodio, Carmen; Escribano, María Isabel

    2015-05-01

    Dehydrins and trehalose are multifunctional protective biomolecules that play a role in counteracting cellular damage during dehydrative stresses. In this paper, we studied dehydrin isoform patterns, dehydrin gene expression and trehalose levels in the skin of Cardinal (Vitis vinifera L.) table grapes, along with their regulation by different cold postharvest storage conditions. Immunoanalysis with K-segment antibody recognizes four constitutive dehydrins (from 17 to 44 kDa) that are tightly regulated by low temperature and high CO2. Phosphatase treatment showed that DHN44 and DHN22 isoforms are phosphorylated polypeptides, while MALDI-TOF MS and MS/MS analysis suggested that 44 kDa polypeptide may be a dehydrin homodimer. At the transcriptional level, dehydrins are also regulated by low temperature and high CO2, showing a fairly good correlation with their mRNA levels. Trehalose was quantified by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), revealing a progressive increase of this metabolite throughout storage at 0 °C and the sudden transitory increases in short-term high CO2-treated fruit. We propose that the constitutive presence and up-regulation of dehydrins and trehalose during low temperature postharvest storage could be positively correlated with the relative chilling tolerance of table grapes and the adaptive responses activated by high CO2 levels to preserve cell water status and to counteract the disruption of physiological processes during cold storage. Copyright © 2015 Elsevier GmbH. All rights reserved.

  1. 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.

    . Appalanaidu, B. Sridevi, B.S.K. Kumar, M.D. Bharati, Ch.V. Subbaiah, T. Acharya, G.D. Rao, R. Viswanadham, L. Gawade, D.T. Manjary, P. P. Kumar, K. Rajeev, N.P.C. Reddy, V.V. Sarma, M.D. Kumar, Y. Sadhuram and T.V.R. Murty National Institute...). The evaluated CO 2 uptake by continental shelves (Borges et al., 2005; Laruelle et al., 2010) range between -0.22 and -1.0 PgC y -1 while Laruelle et al. (2010) estimated emission of CO 2 from estuaries to be +0.27 PgC y -1 . All these estimates, however...

  2. 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

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

    OpenAIRE

    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

    2014-01-01

    This work was funded by the UK Ocean Acidification Research Programme (cofunded by NERC, Defra, and DECC), NERC OARP Grant: NE/H016996/1 “Ocean Acidification Impacts on Sea-Surface Biogeochemistry and climate”, with additional support from the Marine Biological Association (MBA) and the Natural History Museum. 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 mo...

  4. High-quality eddy-covariance CO2 budgets under cold climate conditions

    Science.gov (United States)

    Kittler, Fanny; Eugster, Werner; Foken, Thomas; Heimann, Martin; Kolle, Olaf; Göckede, Mathias

    2017-08-01

    This study aimed at quantifying potential negative effects of instrument heating to improve eddy-covariance flux data quality in cold environments. Our overarching objective was to minimize heating-related bias in annual CO2 budgets from an Arctic permafrost system. We used continuous eddy-covariance measurements covering three full years within an Arctic permafrost ecosystem with parallel sonic anemometers operation with activated heating and without heating as well as parallel operation of open- and closed-path gas analyzers, the latter serving as a reference. Our results demonstrate that the sonic anemometer heating has a direct effect on temperature measurements while the turbulent wind field is not affected. As a consequence, fluxes of sensible heat are increased by an average 5 W m-2 with activated heating, while no direct effect on other scalar fluxes was observed. However, the biased measurements in sensible heat fluxes can have an indirect effect on the CO2 fluxes in case they are used as input for a density-flux WPL correction of an open-path gas analyzer. Evaluating the self-heating effect of the open-path gas analyzer by comparing CO2 flux measurements between open- and closed-path gas analyzers, we found systematically higher CO2 uptake recorded with the open-path sensor, leading to a cumulative annual offset of 96 gC m-2, which was not only the result of the cold winter season but also due to substantial self-heating effects during summer. With an inclined sensor mounting, only a fraction of the self-heating correction for vertically mounted instruments is required.

  5. Positron Annihilation Spectroscopy of High Performance Polymer Films under CO2 Pressure

    Energy Technology Data Exchange (ETDEWEB)

    C.A. Quarles; John R. Klaehn; Eric S. Peterson; Jagoda M. Urban-Klaehn

    2010-08-01

    Positron annihilation Lifetime and Doppler broadening measurements are reported for six polymer films as a function of carbon dioxide absolute pressure ranging from 0 to 45 psi. Since the polymer films were thin and did not absorb all positrons, corrections were made in the lifetime analysis for the absorption of positrons in the positron source and sample holder using the Monte Carlo transport code MCNP. Different polymers are found to behave differently. Some polymers studied form positronium and some, such as the polyimide structures, do not. For those samples that form positronium an interpretation in terms of free volume is possible; for those that don’t form positronium, further work is needed to determine how best to describe the behavior in terms of the bulk positron annihilation parameters. Some polymers exhibit changes in positron lifetime and intensity under CO2 pressure which may be described by the Henry or Langmuir sorption models, while the positron response of other polymers is rather insensitive to the CO2 pressure. The results demonstrate the usefulness of positron annihilation spectroscopy in investigating the sorption of CO2 into various polymers at pressures up to about 3 atm.

  6. Enhancing growth rate and lipid yield of Chlorella with nuclear irradiation under high salt and CO2 stress.

    Science.gov (United States)

    Cheng, Jun; Lu, Hongxiang; Huang, Yun; Li, Ke; Huang, Rui; Zhou, Junhu; Cen, Kefa

    2016-03-01

    In order to produce biodiesel from microalgae cultured with abundant seawater, Chlorella sp. was mutated with (137)Se-γ ray irradiation and domesticated with f/2 seawater culture medium (salinity=3 wt.%) under 15 vol.% CO2 stress. Biomass yield of the mutant increased by 25% compared with wild species and lipid content increased to 54.9%. When nitrogen and phosphorus concentrations in the initial substrate increased, the increased propagation speed of the mutant resulted in decreased cell diameter by 26.6% and decreased cell wall thickness by 69.7%. The dramatically increased biomass yield of the mutant with sufficient initial substrate and relative nitrogen starvation in the later growth period with continuous 15 vol.% CO2 led to an increased lipid yield of 1.0 g/L. The long-chain unsaturated fatty acids increased, whereas short-chain saturated fatty acids decreased. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. 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 CO2 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 CO2 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 CO2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO2. 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.

  8. High CO2 concentration increases relative leaf carbon gain under dynamic light in Dipterocarpus sublamellatus seedlings in a tropical rain forest, Malaysia.

    Science.gov (United States)

    Tomimatsu, Hajime; Iio, Atsuhiro; Adachi, Minaco; Saw, Leng-Guan; Fletcher, Christine; Tang, Yanhong

    2014-09-01

    Understory plants in tropical forests often experience a low-light environment combined with high CO2 concentration. We hypothesized that the high CO2 concentration may compensate for leaf carbon loss caused by the low light, through increasing light-use efficiency of both steady-state and dynamic photosynthetic properties. To test the hypothesis, we examined CO2 gas exchange in response to an artificial lightfleck in Dipterocarpus sublamellatus Foxw. seedlings under contrasting CO2 conditions: 350 and 700 μmol CO2 mol(-1) air in a tropical rain forest, Pasoh, Malaysia. Total photosynthetic carbon gain from the lightfleck was about double when subjected to the high CO2 when compared with the low CO2 concentration. The increase of light-use efficiency in dynamic photosynthesis contributed 7% of the increased carbon gain, most of which was due to reduction of photosynthetic induction to light increase under the high CO2. The light compensation point of photosynthesis decreased by 58% and the apparent quantum yield increased by 26% at the high CO2 compared with those at the low CO2. The study suggests that high CO2 increases photosynthetic light-use efficiency under both steady-state and fluctuating light conditions, which should be considered in assessing the leaf carbon gain of understory plants in low-light environments. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Chemical analysis and surface morphology of enamel and dentin following 9.6mu CO2 laser irradiation versus high speed drilling.

    Science.gov (United States)

    Moshonov, Joshua; Stabholz, Adam; Bar-Hilel, Rita; Peretz, Benjamin

    2005-05-01

    The purpose of the present in vitro study was to determine whether there is a change in the chemical composition and surface morphology of enamel and dentin following 9.6mu CO2 laser irradiation and high-speed drilling. Ten permanent, non-carious, young premolars, extracted for orthodontic reasons, were selected. The crowns were separated longitudinally into two equal parts at their mesiodistal axis. Two areas on the inner enamel surface of each specimen and two on the dentinal surface were selected. A high-speed drill and 9.6mu CO2 laser irradiation were applied to the selected enamel and dentinal areas. A random area on the unlased enamel and on the unlased dentin of each specimen served as controls. The morphology of the specimens was evaluated using scanning electron microscopy. Calcium, phosphorus and oxygen levels were measured using an energy dispersive spectrometer. Mineral analysis revealed no significant difference in the mineral content of the enamel and dentin after laser irradiation or high speed drilling versus the control. Use of the high-speed drill on enamel and dentin resulted in very clear cavity margins, with characteristic grooves, whereas laser irradiation of enamel and dentin did not produce clear margins and the floor of the cavity displayed an irregular surface. The 9.6mu CO2 laser appears to be a promising tool in the clinical setting. However, further investigation is indicated to ensure maximum effectiveness.

  10. Combined and isolated effects of pCO2 and soil water content on carbon isotope discrimination during C3 photosynthesis

    Science.gov (United States)

    Schubert, B.; Jahren, A. H.

    2016-12-01

    Biomass produced via C3 photosynthesis dominates the terrestrial organic matter (TOM) found within the geologic record. Our previous work revealed an increase in net discrimination (Δ13C) ≈ +4‰ across an increase in pCO2 level from ambient to RCO2 = 6x within the model C3 plant Arabidopsis thaliana, grown to maturity under constant conditions of light, moisture, and nutrient availability (Schubert and Jahren, 2012, GCA), leading us to suggest that changes in ancient pCO2 level can be reconstructed from Δ13C within terrestrial sediments. Others have observed an average change in Δ13C ≈ +4‰ when comparing the δ13C value of herbarium samples collected from cool-cold forests to tropical environments against the MAP recorded (Diefendorf et al., 2010, PNAS), leading those authors to suggest that changes in the Δ13C value of TOM recovered from the geological record can be interpreted as changes in precipitation level and/or water availability. Because decreasing moisture availability and increasing pCO2 level exert control over Δ13C through distinctly different mechanisms (i.e., decreased stomatal conductance vs. inhibition of photorespiration, respectively), a simultaneous change in both pCO2 level and moisture availability could combine to influence carbon isotope fractionation. Here we present experiments in which we grew 230 A. thaliana plants at each of 5 levels of pCO2: 390, 685, 1075, 1585, and 2175 ppmv. Within each growth chamber, soil moisture content (θm) was maintained at 1.50 g g-1 for 11 days following germination. Afterwards, we allowed 170 of the plants to dry to θm = 0.83, 0.44, and 0.38 g g-1. After 3 weeks of total growth, tissues were analyzed for δ13C value. We compare the isolated and combined effects of pCO2 and soil moisture upon carbon isotope fractionation across the total range of pCO2 levels reconstructed for the last 350 million years and across moisture levels associated with a 4.5x change in plant biomass.

  11. 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

  12. A Small Decrease in Rubisco Content by Individual Suppression of RBCS Genes Leads to Improvement of Photosynthesis and Greater Biomass Production in Rice Under Conditions of Elevated CO2.

    Science.gov (United States)

    Kanno, Keiichi; Suzuki, Yuji; Makino, Amane

    2017-03-01

    Rubisco limits photosynthesis at low CO2 concentrations ([CO2]), but does not limit it at elevated [CO2]. This means that the amount of Rubisco is excessive for photosynthesis at elevated [CO2]. Therefore, we examined whether a small decrease in Rubisco content by individual suppression of the RBCS multigene family leads to increases in photosynthesis and biomass production at elevated [CO2] in rice (Oryza sativa L.). Our previous studies indicated that the individual suppression of RBCS decreased Rubisco content in rice by 10-25%. Three lines of BC2F2 progeny were selected from transgenic plants with individual suppression of OsRBCS2, 3 and 5. Rubisco content in the selected lines was 71-90% that of wild-type plants. These three transgenic lines showed lower rates of CO2 assimilation at low [CO2] (28 Pa) but higher rates of CO2 assimilation at elevated [CO2] (120 Pa). Similarly, the biomass production and relative growth rate (RGR) of the two lines were also smaller at low [CO2] but greater than that of wild-type plants at elevated [CO2]. This greater RGR was caused by the higher net assimilation rate (NAR). When the nitrogen use efficiency (NUE) for the NAR was estimated by dividing the NAR by whole-plant leaf N content, the NUE for NAR at elevated [CO2] was higher in these two lines. Thus, a small decrease in Rubisco content leads to improvements of photosynthesis and greater biomass production in rice under conditions of elevated CO2. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. A simple high-performance matrix-free biomass molten carbonate fuel cell without CO2 recirculation

    Science.gov (United States)

    Lan, Rong; Tao, Shanwen

    2016-01-01

    In previous reports, flowing CO2 at the cathode is essential for either conventional molten carbonate fuel cells (MCFCs) based on molten carbonate/LiAlO2 electrolytes or matrix-free MCFCs. For the first time, we demonstrate a high-performance matrix-free MCFC without CO2 recirculation. At 800°C, power densities of 430 and 410 mW/cm2 are achieved when biomass—bamboo charcoal and wood, respectively–is used as fuel. At 600°C, a stable performance is observed during the measured 90 hours after the initial degradation. In this MCFC, CO2 is produced at the anode when carbon-containing fuels are used. The produced CO2 then dissolves and diffuses to the cathode to react with oxygen in open air, forming the required CO32− or CO42− ions for continuous operation. The dissolved O2− ions may also take part in the cell reactions. This provides a simple new fuel cell technology to directly convert carbon-containing fuels such as carbon and biomass into electricity with high efficiency. PMID:27540588

  14. Malate metabolism and adaptation to chilling temperature storage by pretreatment with high CO2 levels in Annona cherimola fruit.

    Science.gov (United States)

    Maldonado, Roberto; Sanchez-Ballesta, M Teresa; Alique, Rafael; Escribano, M Isabel; Merodio, Carmen

    2004-07-28

    In this study we focused on the effect of a pretreatment with high (20%) CO2 levels on malic acid metabolism in cherimoya (Annona cherimola Mill) fruit stored at chilling temperature. We analyzed the activity of phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (MDH), and the NADP-malic enzyme (NADP-ME), involved in the carboxylation/decarboxylation of malate. Our results show that CO2 treatment, which improves tolerance to prolonged storage at chilling temperature, was closely linked to considerably greater NADP-ME activity. These results, combined with lower PEPC activity, may explain the significantly lower amount of malic acid and titratable acidity quantified in CO2-treated fruit. Moreover, the high cytoplasmic MDH enzyme activity and the strong stimulation of NADP-ME activity exhibited by CO2-treated fruit could be contributing factors in the maintenance of fruit energy metabolism, pH stability, and the promotion of synthesis of defense compounds that prevent or repair damage caused by chilling temperature. Copyright 2004 American Chemical Society

  15. High CO2 concentration as an inductor agent to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

    Science.gov (United States)

    Ruiz, Cristina; Pla, Maria; Company, Nuri; Riudavets, Jordi; Nadal, Anna

    2016-03-01

    Cationic α-helical antimicrobial peptides such as BP100 are of increasing interest for developing novel phytosanitary or therapeutic agents and products with industrial applications. Biotechnological production of these peptides in plants can be severely impaired due to the toxicity exerted on the host by high-level expression. This can be overcome by using inducible promoters with extremely low activity throughout plant development, although the yields are limited. We examined the use of modified atmospheres using the increased levels of [CO2], commonly used in the food industry, as the inductor agent to biotechnologically produce phytotoxic compounds with higher yields. Here we show that 30% [CO2] triggered a profound transcriptional response in rice leaves, including a change in the energy provision from photosynthesis to glycolysis, and the activation of stress defense mechanisms. Five genes with central roles in up-regulated pathways were initially selected and their promoters successfully used to drive the expression of phytotoxic BP100 in genetically modified (GM) rice. GM plants had a normal phenotype on development and seed production in non-induction conditions. Treatment with 30 % [CO2] led to recombinant peptide accumulation of up to 1 % total soluble protein when the Os.hb2 promoter was used. This is within the range of biotechnological production of other peptides in plants. Using BP100 as a proof-of-concept we demonstrate that very high [CO2] can be considered an economically viable strategy to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

  16. Active microbial community in gas reservoirs in the North German Plain and the effects of high CO2 concentrations

    Science.gov (United States)

    Frerichs, Janin; Gniese, Claudia; Mühling, Martin; Krüger, Martin

    2010-05-01

    From the IPCC report on global warming, it is clear that large-scale solutions are needed immediately to reduce emissions of greenhouse gases. The CO2 capture and storage offers one option for reducing the greenhouse gas emissions. Favourable CO2 storage sites are depleted gas and oil fields and thus, are currently investigated by the BMBF-Geotechnologien RECOBIO-2 project. Our study is focussing on the direct influence of high CO2 concentrations on the autochthonous microbial population and environmental parameters (e.g. availability of nutrients). The gas fields Schneeren in the 'North German Plain' is operated by Gaz de France SUEZ E&V Deutschland GmbH. The conditions in the reservoir formation waters of two bore wells differ in various geochemical parameters (pH, salinity and temperature). In previous studies the community of this gas field was described by Ehinger et al. 2009. Based on these results our study included cultivation and molecular biological approaches. Our results showed significant differences of the community structure in regional distinctions of the gas reservoir. The activity profiles of two wells differed clearly in the inducible activity after substrate addition. The fluids of well A showed a high methane production rate after the addition of methanol or acetate. Well B showed a high sulphide production after the addition of sulphate and hydrogen. The molecular biological analysis of the original fluids supports the activity profile for both sites. The community analysis via real-time PCR showed for the production well head A a higher abundances for Archaea than for B. The community at site B in contrast was dominated by Bacteria. Fluids of both wells were also incubated with high CO2 concentrations in the headspace. These enrichments showed a significant decrease of methane and sulphide production with increasing CO2 levels. Currently, the community composition is analysed to identify changes connected to increased CO2 concentrations. This

  17. 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.

  18. 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

  19. 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 laser diode with minimal heating of the fiber coating and packaging adhesives.

  20. 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...

  1. Design of Control Software for a High-Speed Coherent Doppler Lidar System for CO2 Measurement

    Science.gov (United States)

    Vanvalkenburg, Randal L.; Beyon, Jeffrey Y.; Koch, Grady J.; Yu, Jirong; Singh, Upendra N.; Kavaya, Michael J.

    2010-01-01

    The design of the software for a 2-micron coherent high-speed Doppler lidar system for CO2 measurement at NASA Langley Research Center is discussed in this paper. The specific strategy and design topology to meet the requirements of the system are reviewed. In order to attain the high-speed digitization of the different types of signals to be sampled on multiple channels, a carefully planned design of the control software is imperative. Samples of digitized data from each channel and their roles in data analysis post processing are also presented. Several challenges of extremely-fast, high volume data acquisition are discussed. The software must check the validity of each lidar return as well as other monitoring channel data in real-time. For such high-speed data acquisition systems, the software is a key component that enables the entire scope of CO2 measurement studies using commercially available system components.

  2. Increased Ocean Heat Convergence Into the High Latitudes With CO2 Doubling Enhances Polar-Amplified Warming

    Science.gov (United States)

    Singh, H. A.; Rasch, P. J.; Rose, B. E. J.

    2017-10-01

    We isolate the role of the ocean in polar climate change by directly evaluating how changes in ocean dynamics with quasi-equilibrium CO2 doubling impact high-latitude climate. With CO2 doubling, the ocean heat flux convergence (OHFC) shifts poleward in winter in both hemispheres. Imposing this pattern of perturbed OHFC in a global climate model results in a poleward shift in ocean-to-atmosphere turbulent heat fluxes (both sensible and latent) and sea ice retreat; the high latitudes warm, while the midlatitudes cool, thereby amplifying polar warming. Furthermore, midlatitude cooling is propagated to the polar midtroposphere on isentropic surfaces, augmenting the (positive) lapse rate feedback at high latitudes. These results highlight the key role played by the partitioning of meridional energy transport changes between the atmosphere and ocean in high-latitude climate change.

  3. 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.

  4. Imagining CO2: development and assessment of interactive visualizations for high resolution greenhouse gas observations collected by BEACO2N

    Science.gov (United States)

    Raheja, G.; Shusterman, A.; Martin, S.; Shahar, E.; Laughner, J.; Turner, A. J.; Miller, M. K.; Cohen, R. C.

    2016-12-01

    The Berkeley Atmospheric CO2 Observation Network (BEACO2N) is a high-density network of 28 carbon dioxide sensors distributed around the San Francisco Bay Area that serve to enhance understanding of intra-city variations in CO2 concentrations that are not necessarily captured by sparser networks maintained by local and national air quality management agencies. We partner with designers at the San Francisco Exploratorium to create a suite of interactive exhibits and hands-on activities that creatively visualize data from BEACO2N for general audiences. Museum goers can manipulate a light-up "bar graph" of live CO2 concentrations by exhaling on an in-room sensor, query the current readings of rooftop sensors using a scale model of the Wired Pier observation system, scroll through the data from other BEACO2N sites projected on a 3-D "topographic table" of the Bay Area, and view interpolated CO2 fields driven by research-grade weather models on a nine-screen LCD display. We present lessons learned from these initial installations, from layperson audience feedback to details of the Stochastic Time-Inverted Lagrangian Transport (STILT) model coupled to Weather Research and Forecasting (WRF) weather fields used to generate intuitive concentration maps. We propose that compelling visual demonstrations of elevated CO2 concentrations due to routine small-scale high-emission anthropogenic activities (e.g. rush hour) and/or special events (such as fireworks or factory fires) generate deeper engagement in local environmental issues and interest in undertaking personal actions that can become part of the broader climate solution. While global means and other large-scale aggregate climate metrics can lead to feelings of disconnect and subsequent ambivalence, via such exhibitions, distributed network instruments like BEACO2N can provide the local sensitivity needed to "personalize" greenhouse gas concentrations to a given individual or community and incite the drive toward

  5. On the relative influence of initial H2O and CO2 contents on the primitive surface conditions and evolution of rocky (exo-)planets

    Science.gov (United States)

    Salvador, Arnaud; Massol, Helène; Davaille, Anne; Marcq, Emmanuel; Chassefière, Eric; Sarda, Philippe

    2017-04-01

    Estimates of initial volatile contents inside planets primitive magma oceans (hereafter « MO ») varies by several orders of magnitude. However, the release of greenhouse gasses such as H2O and CO2 during cooling and crystallization of the MO will greatly affect the atmosphere formation, the planet cooling time scale, its surface temperature, and its potential for water condensation and habitability. We have therefore conducted a systematic study of the influence of volatile contents on the secular convective cooling and solidification of a MO in interaction with the outgassed atmosphere. We developed a 1D model coupling MO dynamics with a convective-radiative atmosphere using either a grey approximation or k-correlated opacities, with or without clouds. Initial CO2 and H2O contents were varied between 10-3 and 14×10-2 wt%, and from 0.05 to 2.2 times the Earth Ocean current mass (MEO). We considered an Earth-like planet, with its Sun intensity ranging from half to the present-day value and a solar distance from 0.63 to 1.30 AU. The atmosphere albedo was varied between 0.2 and 0.8. All cases shows the same evolution in two main episodes : after (1) a very rapid cooling stage driven by the MO cooling and crystallization, the planet reaches (2) a quasi-steady state where subsequent evolution will take billions of years. The surface temperature is controlled by the balance between the IR outgoing flux, and the heat flux out of the MO during (1), and the solar flux during (2). At the end of the first regime (hereafter « ERCS »), the planetary surface can (i) still be molten or partially-molten, (ii) solid but dry, (iii) solid and covered by a water ocean, depending on the initial volatile contents, sun characteristics and sun-planet distance. Regimes diagrams were obtained. There is a critical sun-planet distance Dc below which water will never condense, whatever the initial volatile content. For distances larger than Dc, water condensation strongly depends on the

  6. Raman spectroscopy differentiates squamous cell carcinoma (SCC) from normal skin following treatment with a high-powered CO2 laser.

    Science.gov (United States)

    Fox, Sara A; Shanblatt, Ashley A; Beckman, Hugh; Strasswimmer, John; Terentis, Andrew C

    2014-12-01

    The number of cases of non-melanoma skin cancer (NMSC), which include squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), continues to rise as the aging population grows. Mohs micrographic surgery has become the treatment of choice in many cases but is not always necessary or feasible. Ablation with a high-powered CO2 laser offers the advantage of highly precise, hemostatic tissue removal. However, confirmation of complete cancer removal following ablation is difficult. In this study we tested for the first time the feasibility of using Raman spectroscopy as an in situ diagnostic method to differentiate NMSC from normal tissue following partial ablation with a high-powered CO2 laser. Twenty-five tissue samples were obtained from eleven patients undergoing Mohs micrographic surgery to remove NMSC tumors. Laser treatment was performed with a SmartXide DOT Fractional CO2 Laser (DEKA Laser Technologies, Inc.) emitting a wavelength of 10.6 μm. Treatment levels ranged from 20 mJ to 1200 mJ total energy delivered per laser treatment spot (350 μm spot size). Raman spectra were collected from both untreated and CO2 laser-treated samples using a 785 nm diode laser. Principal Component Analysis (PCA) and Binary Logistic Regression (LR) were used to classify spectra as originating from either normal or NMSC tissue, and from treated or untreated tissue. Partial laser ablation did not adversely affect the ability of Raman spectroscopy to differentiate normal from cancerous residual tissue, with the spectral classification model correctly identifying SCC tissue with 95% sensitivity and 100% specificity following partial laser ablation, compared with 92% sensitivity and 60% selectivity for untreated NMSC tissue. The main biochemical difference identified between normal and NMSC tissue was high levels of collagen in the normal tissue, which was lacking in the NMSC tissue. The feasibility of a combined high-powered CO2 laser ablation, Raman diagnostic procedure for the

  7. Energy balance in high-quality cutting of steel by fiber and CO2 lasers

    Science.gov (United States)

    Fomin, V. M.; Golyshev, A. A.; Orishich, A. M.; Shulyat'ev, V. B.

    2017-03-01

    The energy balance of laser cutting of low-carbon and stainless steel sheets with the minimum roughness of the cut surface is experimentally studied. Experimental data obtained in wide ranges of cutting parameters are generalized with the use of dimensionless parameters (Peclet number and absorbed laser energy). It is discovered for the first time that the minimum roughness is ensured at a certain value of energy per unit volume of the melt (approximately 26 J/mm3), regardless of the gas type (oxygen or nitrogen) and laser type (fiber laser with a wavelength of 1.07 μm or CO2 laser with a wavelength of 10.6 μm).

  8. Mesoporous thin-film on highly-sensitive resonant chemical sensor for relative humidity and CO2 detection.

    Science.gov (United States)

    Lee, Hyunjoo J; Park, Kwan Kyu; Kupnik, Mario; Melosh, Nicholas A; Khuri-Yakub, Butrus T

    2012-04-03

    Distributed sensing of gas-phase chemicals is a promising application for mesoporous materials when combined with highly sensitive miniaturized gas sensors. We present a direct application of a mesoporous silica thin film on a highly sensitive miniaturized resonant chemical sensor with a mass sensitivity at the zeptogram scale for relative humidity and CO(2) detection. Using mesoporous silica thin-film, we report one of the lowest volume resolutions and a sensitive detection of 5.1 × 10(-4)% RH/Hz to water vapor in N(2), which is 70 times higher than a device with a nontemplated silica layer. In addition, a mesoporous thin-film that is functionalized with an amino-group is directly applied on the resonant sensor, which exhibits a volume sensitivity of 1.6 × 10(-4)%/Hz and a volume resolution of 1.82 × 10(-4)% to CO(2) in N(2).

  9. Atmospheric measurement of point source fossil fuel CO2 emissions

    Science.gov (United States)

    Turnbull, J. C.; Keller, E. D.; Baisden, W. T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2013-11-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m a.g.l. We also determined the surface CO2ff content averaged over several weeks from the 14CO2 content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~1 week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14CO2 sampling strategies.

  10. Regulation of defense and cryoprotective proteins by high levels of CO(2) in Annona fruit stored at chilling temperature.

    Science.gov (United States)

    Goñi, Oscar; Sanchez-Ballesta, María T; Merodio, Carmen; Escribano, María I

    2009-02-15

    This study focuses on how the length of exposure to chilling temperature and atmosphere storage conditions regulate the hydrolytic activity and expression of chitinase (PR-Q) and 1,3-beta-glucanase (PR-2) isoenzymes in cherimoyas (Annona cherimola Mill.). Storage at 6 degrees C modified the expression of constitutive isoenzymes and induced the appearance of novel acidic chitinases, AChi26 and AChi24, at the onset of the storage period, and of a basic chitinase, BChi33, after prolonged storage. The induction of this basic isoenzyme was concomitant with the accumulation of basic constitutive 1,3-beta-glucanases. These low-temperature-induced chitinases modified the growth inhibition in vitro of Botrytis cinerea. Short-term high CO(2) treatment activated a coordinated response of acidic chitinases and 1,3-beta-glucanases after prolonged storage at chilling temperature. Moreover, the high in vitro cryoprotective activity of CO(2)-treated protein extracts was associated with the induction of two low molecular mass isoenzymes, AGlu19 and BChi14. Thus, exposure to high concentrations of CO(2) modified the response of fruit to low temperature, inducing the synthesis of cryoprotectant proteins such as specific pathogenesis-related isoenzymes that could be functionally associated with an increase in chilling tolerance in vivo.

  11. Transcriptome and key genes expression related to carbon fixation pathways in Chlorella PY-ZU1 cells and their growth under high concentrations of CO2.

    Science.gov (United States)

    Huang, Yun; Cheng, Jun; Lu, Hongxiang; He, Yong; Zhou, Junhu; Cen, Kefa

    2017-01-01

    The biomass yield of Chlorella PY-ZU1 drastically increased when cultivated under high CO2 condition compared with that cultivated under air condition. However, less attention has been given to the microalgae photosynthetic mechanisms response to different CO2 concentrations. The genetic reasons for the higher growth rate, CO2 fixation rate, and photosynthetic efficiency of microalgal cells under higher CO2 concentration have not been clearly defined yet. In this study, the Illumina sequencing and de novo transcriptome assembly of Chlorella PY-ZU1 cells cultivated under 15% CO2 were performed and compared with those of cells grown under air. It was found that carbonic anhydrase (CAs, enzyme for interconversion of bicarbonate to CO2) dramatically decreased to near 0 in 15% CO2-grown cells, which indicated that CO2 molecules directly permeated into cells under high CO2 stress without CO2-concentrating mechanism. Extrapolating from the growth conditions and quantitative Real-Time PCR of CCM-related genes, the Km (CO2) (the minimum intracellular CO2 concentration that rubisco required) of Chlorella PY-ZU1 might be in the range of 80-192 μM. More adenosine triphosphates was saved for carbon fixation-related pathways. The transcript abundance of rubisco (the most important enzyme of CO2 fixation reaction) was 16.3 times higher in 15% CO2-grown cells than that under air. Besides, the transcript abundances of most key genes involved in carbon fixation pathways were also enhanced in 15% CO2-grown cells. Carbon fixation and nitrogen metabolism are the two most important metabolisms in the photosynthetic cells. These genes related to the two most metabolisms with significantly differential expressions were beneficial for microalgal growth (2.85 g L(-1)) under 15% CO2 concentration. Considering the micro and macro growth phenomena of Chlorella PY-ZU1 under different concentrations of CO2 (0.04-60%), CO2 transport pathways responses to different CO2 (0

  12. CO2 Emission Factors for Coals

    Directory of Open Access Journals (Sweden)

    P. Orlović-Leko

    2015-03-01

    (calcite and siderite directly contribute CO2 when they decompose during coal combustion. Variations in the maceral content can also influence CO2 emissions; high inertinite contents increase CO2 emissions. Sulphur in coal reduces EF(CO2. Fuel analysis is very important when estimating greenhouse gas emissions and emission factors. In this preliminary study, based on the results of the fuel analysis, CO2 emission factors for coals and peat from Livno, B&H have been calculated. EF(CO2 is defined as the amount of carbon dioxide emission per unit net calorific values of the fuel. Net calorific value (the lower heating value corresponds to the heat produced by combustion where total water in the combustion products exists as water vapour. The EF(CO2 obtained for sub-bituminous coal, lignite and peat were: 98.7, 109.5, and 147.9 t TJ−1, respectively, which correspond to the following net calorific values: 20.6, 11.5 and 3.6 MJ kg−1. The heating value is generally known to increase with the increase in carbon content (this parameter is connected with the degree of coalification, coal age. The other indispensable parameters are hydrogen, which has a positive effect on the net calorific value, and oxygen and water which impact the net calorific value negatively. The differences in net calorific values can be explained in part by the difference of total moisture content among the different fuel types. The CO2 emission factors calculated in this study were compared with those of IPCC. A significant difference was observed for peat (39.5 %, followed by lignite (8.2 % and sub-bituminous coal (4.3 %.

  13. 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

    2017-05-19

    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).

  14. 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.

  15. 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

    2014-01-01

    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. PMID:25077027

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Time-resolved remote Raman study of minerals under supercritical CO2 and high temperatures relevant to Venus exploration.

    Science.gov (United States)

    Sharma, Shiv K; Misra, Anupam K; Clegg, Samuel M; Barefield, James E; Wiens, Roger C; Acosta, Tayro

    2010-07-13

    We report time-resolved (TR) remote Raman spectra of minerals under supercritical CO(2) (approx. 95 atm pressure and 423 K) and under atmospheric pressure and high temperature up to 1003 K at distances of 1.5 and 9 m, respectively. The TR Raman spectra of hydrous and anhydrous sulphates, carbonate and silicate minerals (e.g. talc, olivine, pyroxenes and feldspars) under supercritical CO(2) (approx. 95 atm pressure and 423 K) clearly show the well-defined Raman fingerprints of each mineral along with the Fermi resonance doublet of CO(2). Besides the CO(2) doublet and the effect of the viewing window, the main differences in the Raman spectra under Venus conditions are the phase transitions, the dehydration and decarbonation of various minerals, along with a slight shift in the peak positions and an increase in line-widths. The dehydration of melanterite (FeSO(4).7H(2)O) at 423 K under approximately 95 atm CO(2) is detected by the presence of the Raman fingerprints of rozenite (FeSO(4).4H(2)O) in the spectrum. Similarly, the high-temperature Raman spectra under ambient pressure of gypsum (CaSO(4).2H(2)O) and talc (Mg(3)Si(4)O(10)(OH)(2)) indicate that gypsum dehydrates at 518 K, but talc remains stable up to 1003 K. Partial dissociation of dolomite (CaMg(CO(3))(2)) is observed at 973 K. The TR remote Raman spectra of olivine, alpha-spodumene (LiAlSi(2)O(6)) and clino-enstatite (MgSiO(3)) pyroxenes and of albite (NaAlSi(3)O(8)) and microcline (KAlSi(3)O(8)) feldspars at high temperatures also show that the Raman lines remain sharp and well defined in the high-temperature spectra. The results of this study show that TR remote Raman spectroscopy could be a potential tool for exploring the surface mineralogy of Venus during both daytime and nighttime at short and long distances.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Laser CO2 vaporization for high-grade cervical intraepithelial neoplasia: a long-term follow-up series.

    Science.gov (United States)

    Fallani, Maria Grazia; Penna, Carlo; Fambrini, Massimiliano; Marchionni, Mauro

    2003-10-01

    The goal of this study was to evaluate the effectiveness of laser CO(2) vaporization for conservative treatment of ectocervical high-grade cervical intraepithelial neoplasia (CIN) particularly by the evaluation of the reappearance risk of disease in long-term follow-up. One hundred fifty-nine patients were submitted to CO(2) laser vaporization for high-grade CIN and followed up for a minimum of 5 years. Selection of cases, depth of ablation, complications, and cure rate (percentage of treated patients in whom there was no recurrent/persistent high-grade CIN at the 5-year follow-up examination) were retrospectively evaluated. Selected cases for colposcopy were submitted to a 6-mm mean depth of vaporization without intra- or postoperative complications. The cure rate for a single treatment was 97.5% and a satisfactory colposcopic follow-up was possible in 99.4% of treated patients. No case of invasive carcinoma occurred after a mean follow-up of 7.1 years. Four cases (2.5%) were high-grade CIN persistence observed after a mean time of 3.75 months, suggesting incomplete destruction of the deepest part of the lesion involving the glandular crypt base. Long-term follow-up proves that laser CO(2) vaporization still has a place in the treatment of CIN. In selected cases it represents a safe alternative for conization in the treatment of high-grade CIN, but colposcopic expertise is essential for adequate preoperative selection of cases.

  6. Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People?

    Science.gov (United States)

    Pendleton, Linwood; Comte, Adrien; Langdon, Chris; Ekstrom, Julia A; Cooley, Sarah R; Suatoni, Lisa; Beck, Michael W; Brander, Luke M; Burke, Lauretta; Cinner, Josh E; Doherty, Carolyn; Edwards, Peter E T; Gledhill, Dwight; Jiang, Li-Qing; van Hooidonk, Ruben J; Teh, Louise; Waldbusser, George G; Ritter, Jessica

    2016-01-01

    Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses: 1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and 2) ocean acidification. These global stressors: cannot be avoided by local management, compound local stressors, and hasten the loss of ecosystem services. Impacts to people will be most grave where a) human dependence on coral reef ecosystems is high, b) sea surface temperature reaches critical levels soonest, and c) ocean acidification levels are most severe. Where these elements align, swift action will be needed to protect people's lives and livelihoods, but such action must be informed by data and science. Designing policies to offset potential harm to coral reef ecosystems and people requires a better understanding of where CO2-related global environmental stresses could cause the most severe impacts. Mapping indicators has been proposed as a way of combining natural and social science data to identify policy actions even when the needed science is relatively nascent. To identify where people are at risk and where more science is needed, we map indicators of biological, physical and social science factors to understand how human dependence on coral reef ecosystems will be affected by globally-driven threats to corals expected in a high-CO2 world. Western Mexico, Micronesia, Indonesia and parts of Australia have high human dependence and will likely face severe combined threats. As a region, Southeast Asia is particularly at risk. Many of the countries most dependent upon coral reef ecosystems are places for which we have the least robust data on ocean acidification. These areas require new data and interdisciplinary scientific research to help coral reef-dependent human communities better prepare for a high CO2 world.

  7. Determining the high variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake

    Directory of Open Access Journals (Sweden)

    Denise Tonetta

    2014-09-01

    Full Text Available The aquatic metabolism comprises production and mineralization of organic matter through biological processes, such as primary production and respiration that can be estimated by gases concentration in the water column. AIM: The study aimed to assess the temporal variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake. Our hypotheses are i high variability in meteorological conditions, such as temperature and light, drive the high variability in pCO2 and pO2, and ii the lake is permanently heterotrophic due to the low phosphorus concentration. METHODS: We estimated pCO2 from pH-alkalinity method, and pO2 from dissolved oxygen concentration and water temperature measured in free-water during 24 hours in the autumn, winter, spring and summer. RESULTS: Our findings showed that limnological variables had low temporal variability, while the meteorological variables and pCO2 presented a high coefficient of variation, which is representative of each climatic season. In autumn and winter, it was recorded that the lake was supersaturated in CO2 relative to the atmosphere, while in spring and summer CO2 concentration was below the concentration found in the atmosphere. Over 24 hours, pCO2 also showed high variability, with autumn presenting higher concentration during the night when compared to daytime. Water temperature and chlorophyll a were negatively correlated with pCO2, while pO2 was positively correlated with wind and light. CONCLUSION: Agreeing with our first hypothesis, pCO2 showed an expressive temporal variation in a subtropical lake associated to the high variability in meteorological conditions. On the other hand, our second hypothesis was not confirmed, since Peri Lake exported CO2 to the atmosphere in some periods and in others, CO2 was removed from the atmosphere.

  8. Monitoring the bio-stimulation of hydrocarbon-contaminated soils by measurements of soil electrical properties, and CO2 content and its 13C/12C isotopic signature

    Science.gov (United States)

    Noel, C.; Gourry, J.; Ignatiadis, I.; Colombano, S.; Dictor, M.; Guimbaud, C.; Chartier, M.; Dumestre, A.; Dehez, S.; Naudet, V.

    2013-12-01

    Hydrocarbon contaminated soils represent an environmental issue as it impacts on ecosystems and aquifers. Where significant subsurface heterogeneity exists, conventional intrusive investigations and groundwater sampling can be insufficient to obtain a robust monitoring of hydrocarbon contaminants, as the information they provide is restricted to vertical profiles at discrete locations, with no information between sampling points. In order to obtain wider information in space volume on subsurface modifications, complementary methods can be used like geophysics. Among geophysical methods, geoelectrical techniques such as electrical resistivity (ER) and induced polarization (IP) seem the more promising, especially to study the effects of biodegradation processes. Laboratory and field geoelectrical experiments to characterize soils contaminated by oil products have shown that mature hydrocarbon-contaminated soils are characterized by enhanced electrical conductivity although hydrocarbons are electrically resistive. This high bulk conductivity is due to bacterial impacts on geological media, resulting in changes in the chemical and physical properties and thus, to the geophysical properties of the ground. Moreover, microbial activity induced CO2 production and isotopic deviation of carbon. Indeed, produced CO2 will reflect the pollutant isotopic signature. Thus, the ratio δ13C(CO2) will come closer to δ13C(hydrocarbon). BIOPHY, project supported by the French National Research Agency (ANR), proposes to use electrical methods and gas analyses to develop an operational and non-destructive method for monitoring in situ biodegradation of hydrocarbons in order to optimize soil treatment. Demonstration field is located in the South of Paris (France), where liquid fuels (gasoline and diesel) leaked from some tanks in 1997. In order to stimulate biodegradation, a trench has been dug to supply oxygen to the water table and thus stimulate aerobic metabolic bioprocesses. ER and

  9. Electronic Coupling in a Highly Preorganized Bimetallic Complex Comprising Pyrazolate-Bridged CpMn(CO)2 Moieties

    OpenAIRE

    Röder, Jens C.; Meyer, Franc; Hyla-Kryspin, Isabella; Winter, Rainer; Kaifer, Elisabeth

    2003-01-01

    By means of a multistep synthetic procedure a dimanganese complex has been prepared, in which a N,N′-bridging pyrazolate ligand spans two CpMn(CO)2 subunits in a highly preorganized chelate arrangement. The Xray crystallographic analyses of the MnIMnI complex K+1− and of its non-chelate precursor complex elucidate details of the molecular structure, in particular an unusual pyrazolate binding mode in the solid state and intertwining of the CO ligands in the crowded bimetallic array 1−. The Mn...

  10. Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature

    Science.gov (United States)

    Wang, Hongbo; Zeuschner, Janek; Eremets, Mikhail; Troyan, Ivan; Willams, Jonathan

    2016-01-01

    Carbonic acid (H2CO3) forms in small amounts when CO2 dissolves in H2O, yet decomposes rapidly under ambient conditions of temperature and pressure. Despite its fleeting existence, H2CO3 plays an important role in the global carbon cycle and in biological carbonate-containing systems. The short lifetime in water and presumed low concentration under all terrestrial conditions has stifled study of this fundamental species. Here, we have examined CO2/H2O mixtures under conditions of high pressure and high temperature to explore the potential for reaction to H2CO3 inside celestial bodies. We present a novel method to prepare solid H2CO3 by heating CO2/H2O mixtures at high pressure with a CO2 laser. Furthermore, we found that, contrary to present understanding, neutral H2CO3 is a significant component in aqueous CO2 solutions above 2.4 GPa and 110 °C as identified by IR-absorption and Raman spectroscopy. This is highly significant for speciation of deep C-O-H fluids with potential consequences for fluid-carbonate-bearing rock interactions. As conditions inside subduction zones on Earth appear to be most favorable for production of aqueous H2CO3, a role in subduction related phenomena is inferred.

  11. Combustion of hythane diluted with CO2

    Directory of Open Access Journals (Sweden)

    Hraiech Ibtissem

    2015-01-01

    Full Text Available With increasing concern about energy shortage and environmental protection, improving engine fuel economy and reducing exhaust emissions have become major research topics in combustion and engine development. Hythane (a blend of hydrogen H2 and natural gas NG has generated a significant interest as an alternative fuel for the future. This paper describes an experimental study of the effects of CO2 addition on the stability of a turbulent jet diffusion NG-H2 flame. The mole fraction of hydrogen (% H2 in NG-H2 mixture was varied from 0% to 50%. The equivalence ratio of the hythane/CO2/air mixture was kept at stoichiometry. The results show that the lift-off height increases with the addition of CO2 at various % H2 content in hythane. However, we observe that with 20% H2, we can obtain a stable flame diluted with 40% CO2, while for 0% H2, the flame is blown out above 20% CO2. This means that the limits of flame blowing out are pushed with the additions of H2. Moreover, the results show that for %H2 content in NG-H2 fuel up to 10%, the addition of CO2 could produce lifted flame if the % CO2 is low. At higher % CO2 dilution, flame would remain attached until blow-out. This is mainly due to the fact that the dilution leads to ejection velocities very high but reactivity of the mixture does not change so the flame tends to stretch.

  12. Atmospheric measurement of point source fossil CO2 emissions

    Science.gov (United States)

    Turnbull, J. C.; Keller, E. D.; Baisden, T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2014-05-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m above ground level. We also determined the surface CO2ff content averaged over several weeks from the 14C content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~ one week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14C sampling strategies.

  13. Selectivity on Etching: Creation of High-Energy Facets on Copper Nanocrystals for CO2 Electrochemical Reduction.

    Science.gov (United States)

    Wang, Zhenni; Yang, Guang; Zhang, Zhaorui; Jin, Mingshang; Yin, Yadong

    2016-04-26

    Creating high-energy facets on the surface of catalyst nanocrystals represents a promising method for enhancing their catalytic activity. Herein we show that crystal etching as the reverse process of crystal growth can directly endow nanocrystal surfaces with high-energy facets. The key is to avoid significant modification of the surface energies of the nanocrystal facets by capping effects from solvents, ions, and ligands. Using Cu nanocubes as the starting material, we have successfully demonstrated the creation of high-energy facets in metal nanocrystals by controlled chemical etching. The etched Cu nanocrystals with enriched high-energy {110} facets showed significantly enhanced activity toward CO2 reduction. We believe the etching-based strategy could be extended to the synthesis of nanocrystals of many other catalysts with more active high-energy facets.

  14. Photosynthetic down-regulation in N2-fixing alfalfa under elevated CO2 alters rubisco content and decreases nodule metabolism via nitrogenase and tricarboxylic acid cycle

    OpenAIRE

    Erice, Gorka; Sanz-Sáez, Álvaro; Ricardo F Aroca; Ruiz-Lozano, Juan Manuel; Avice, Jean Christophe; Irigoyen, Juan José; Sánchez-Díaz, Manuel; Aranjuelo, Iker

    2014-01-01

    Although responsiveness of N2-fixing plants to elevated CO2 conditions have been analyzed in previous studies, important uncertainties remain in relation to the effect enhanced CO2 in nodule proteomic profile and its implication in leaf responsiveness. The aim of our study was to deepen our understanding of the relationship between leaf and nodule metabolism of N2-fixing alfalfa plants after long-term exposure to elevated CO2. After 30-day exposure to elevated CO2, plants showed photosyntheti...

  15. Soret Effect Study on High-Pressure CO2-Water Solutions Using UV-Raman Spectroscopy and a Concentric-Tube Optical Cell

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; McGrail, B. Peter; Maupin, Gary D.

    2012-01-01

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O (or D2O), which were subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O at 10 MPa and temperatures near the critical point of CO2 had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude of |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19oC. The presence of 1 M NaCl did not make a difference. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for H2O were too weak to measure with confidence even at the limit of D2O solubility.

  16. Hierarchical chestnut-like MnCo2O4 nanoneedles grown on nickel foam as binder-free electrode for high energy density asymmetric supercapacitors

    Science.gov (United States)

    Hui, Kwun Nam; Hui, Kwan San; Tang, Zikang; Jadhav, V. V.; Xia, Qi Xun

    2016-10-01

    Hierarchical chestnut-like manganese cobalt oxide (MnCo2O4) nanoneedles (NNs) are successfully grown on nickel foam using a facile and cost-effective hydrothermal method. High resolution TEM image further verifies that the chestnut-like MnCo2O4 structure is assembled by numerous 1D MnCo2O4 nanoneedles, which are formed by numerous interconnected MnCo2O4 nanoparticles with grain diameter of ∼10 nm. The MnCo2O4 electrode exhibits high specific capacitance of 1535 F g-1 at 1 A g-1 and good rate capability (950 F g-1 at 10 A g-1) in a 6 M KOH electrolyte. An asymmetric supercapacitor is fabricated using MnCo2O4 NNs on Ni foam (MnCo2O4 NNs/NF) as the positive electrode and graphene/NF as the negative electrode. The device shows an operation voltage of 1.5 V and delivers a high energy density of ∼60.4 Wh kg-1 at a power density of ∼375 W kg-1. Moreover, the device exhibits an excellent cycling stability of 94.3% capacitance retention after 12000 cycles at 30 A g-1. This work demonstrates that hierarchical chestnut-like MnCo2O4 NNs could be a promising electrode for the high performance energy storage devices.

  17. Preferentially Oriented Ag Nanocrystals with Extremely High Activity and Faradaic Efficiency for CO2 Electrochemical Reduction to CO.

    Science.gov (United States)

    Peng, Xiong; Karakalos, Stavros G; Mustain, William E

    2018-01-17

    Selective electrochemical reduction of CO2 is one of the most important processes to study because of its promise to convert this greenhouse gas to value-added chemicals at low cost. In this work, a simple anodization treatment was devised that first oxidizes Ag to Ag2CO3, then uses rapid electrochemical reduction to create preferentially oriented nanoparticles (PONs) of metallic Ag (PON-Ag) with high surface area as well as high activity and very high selectivity for the reduction of CO2 to CO. The PON-Ag catalyst was dominated by (110) and (100) orientation, which allowed PON-Ag to achieve a CO Faradaic efficiency of 96.7% at an operating potential of -0.69 V vs RHE. This performance is not only significantly higher than that of polycrystalline Ag (60% at -0.87 V vs RHE) but also represents one of the best combinations of activity and selectivity achieved to date - all with a very simple, scalable approach to electrode fabrication.

  18. Elevated CO2 induces substantial and persistent declines in forage digestibility and protein content irrespective of warming in mixed-grass prairie

    Science.gov (United States)

    Increasing atmospheric [CO2] and temperature are expected to affect the productivity, species composition, biogeochemistry, and therefore the quantity and quality of forage available to herbivores in rangeland ecosystems. Both elevated CO2 (eCO2) and warming affect plant tissue chemistry through mul...

  19. Comparison of Source Partitioning Methods for CO2 and H2O Fluxes Based on High Frequency Eddy Covariance Data

    Science.gov (United States)

    Klosterhalfen, Anne; Moene, Arnold; Schmidt, Marius; Ney, Patrizia; Graf, Alexander

    2017-04-01

    Source partitioning of eddy covariance (EC) measurements of CO2 into respiration and photosynthesis is routinely used for a better understanding of the exchange of greenhouse gases, especially between terrestrial ecosystems and the atmosphere. The most frequently used methods are usually based either on relations of fluxes to environmental drivers or on chamber measurements. However, they often depend strongly on assumptions or invasive measurements and do usually not offer partitioning estimates for latent heat fluxes into evaporation and transpiration. SCANLON and SAHU (2008) and SCANLON and KUSTAS (2010) proposed an promising method to estimate the contributions of transpiration and evaporation using measured high frequency time series of CO2 and H2O fluxes - no extra instrumentation necessary. This method (SK10 in the following) is based on the spatial separation and relative strength of sources and sinks of CO2 and water vapor among the sub-canopy and canopy. Assuming that air from those sources and sinks is not yet perfectly mixed before reaching EC sensors, partitioning is estimated based on the separate application of the flux-variance similarity theory to the stomatal and non-stomatal components of the regarded fluxes, as well as on additional assumptions on stomatal water use efficiency (WUE). The CO2 partitioning method after THOMAS et al. (2008) (TH08 in the following) also follows the argument that the dissimilarities of sources and sinks in and below a canopy affect the relation between H2O and CO2 fluctuations. Instead of involving assumptions on WUE, TH08 directly screens their scattergram for signals of joint respiration and evaporation events and applies a conditional sampling methodology. In spite of their different main targets (H2O vs. CO2), both methods can yield partitioning estimates on both fluxes. We therefore compare various sub-methods of SK10 and TH08 including own modifications (e.g., cluster analysis) to each other, to established

  20. CO2 blood test

    Science.gov (United States)

    Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum; Acidosis - CO2; Alkalosis - CO2 ... The CO2 test is most often done as part of an electrolyte or basic metabolic panel. Changes in your ...

  1. Exploring the MIS M2 glaciation occurring during a warm and high atmospheric CO2 Pliocene background climate

    Science.gov (United States)

    Tan, Ning; Ramstein, Gilles; Dumas, Christophe; Contoux, Camille; Ladant, Jean-Baptiste; Sepulchre, Pierre; Zhang, Zhongshi; De Schepper, Stijn

    2017-08-01

    Prior to the Northern Hemisphere glaciation around ∼2.7 Ma, a large global glaciation corresponding to a 20 to 60 m sea-level drop occurred during Marine Isotope Stage (MIS) M2 (3.312-3.264 Ma), interrupted the period of global warmth and high CO2 concentration (350-450 ppmv) of the mid Piacenzian. Unlike the late Quaternary glaciations, the M2 glaciation only lasted 50 kyrs and occurred under uncertain CO2 concentration (220-390 ppmv). The mechanisms causing the onset and termination of the M2 glaciation remain enigmatic, but a recent geological hypothesis suggests that the re-opening and closing of the shallow Central American Seaway (CAS) might have played a key role. In this article, thanks to a series of climate simulations carried out using a fully coupled Atmosphere Ocean General Circulation Model (GCM) and a dynamic ice sheet model, we show that re-opening of the shallow CAS helps precondition the low-latitude oceanic circulation and affects the related northward energy transport, but cannot alone explain the onset of the M2 glaciation. The presence of a shallow open CAS, together with favourable orbital parameters, 220 ppmv of CO2 concentration, and the related vegetation and ice sheet feedback, led to a global ice sheet build-up producing a global sea-level drop in the lowest range of proxy-derived estimates. More importantly, our results show that the simulated closure of the CAS has a negligible impact on the NH ice sheet melt and cannot explain the MIS M2 termination.

  2. Rovibrational states of N3- and CO2 up to high J: a theoretical study beyond fc-CCSD(T).

    Science.gov (United States)

    Sebald, Peter; Stein, Christopher; Oswald, Rainer; Botschwina, Peter

    2013-12-19

    An accurate near-equilibrium potential energy surface (PES) has been constructed for the azide ion (N(3)(-)) on the basis of coupled cluster calculations up to CCSDTQ (Kállay, M.; Surján, P. R. J. Chem. Phys. 2001, 115, 2945.), with contributions from inner-shell correlation and special relativity being taken into account as well. A larger number of rovibrational states has been investigated by variational calculations with Watson's isomorphic Hamiltonian for linear molecules. Analogous calculations for CO2 demonstrate the high quality of this type of calculations. The G(v) values of the symmetric stretching and bending vibration of 14N(3)(-) are predicted to be ν1 = 1307.9 cm(-1) and ν2 = 629.3 cm(-1), with an uncertainty of ca. 1 cm(-1). Fermi resonance is less pronounced for the lower polyads of 14N(3)(-) compared with 12C16O2 but is as strong as in CO2 for the lowest diad of isotopologue 15-14-15. The band origin of the antisymmetric stretching vibration of 14N(3)(-) is calculated to be ν3 = 1986.4 cm(-1), only 0.1 cm(-1) lower than the experimental value. The corresponding vibrational transition dipole moment is predicted to be as large as μ = 0.476 D, 46% higher than calculated for CO2. The perturbed combination tone (01(1)1), which was accessible through diode laser IR spectroscopy, undergoes anharmonic interaction with at least two other vibrational states.

  3. 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.

  4. Synthesis of Two-dimensional Microporous Carbonaceous Polymer Nanosheets and Their Application as High-performance CO2 Capture Sorbent.

    Science.gov (United States)

    Zhang, Miao; Liu, Lin; He, Teng; Wu, Guotao; Chen, Ping

    2016-06-21

    The synthesis of two-dimensional (2D) polymer nanosheets with a well-defined microporous structure remains challenging in materials science. Here, a new kind of 2D microporous carbonaceous polymer nanosheets was synthesized through polymerization of a very low concentration of 1,4-dicyanobenzene in molten zinc chloride at 400-500 °C. This type of nanosheets has a thickness in the range of 3-20 nm, well-defined microporosity, a high surface area (∼537 m(2)  g(-1) ), and a large micropore volume (∼0.45 cm(3)  g(-1) ). The microporous carbonaceous polymer nanosheets exhibit superior CO2 sorption capability (8.14 wt % at 298 K and 1 bar) and a relatively high CO2 selectivity toward N2 (25.6). Starting from different aromatic nitrile monomers, a variety of 2D carbonaceous polymer nanosheets can be obtained showing a certain universality of the ionothermal method reported herein. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Narrow Energy-Spread Proton Beams Generated in a Gas Jet by High-Power CO2 Laser Pulses

    Science.gov (United States)

    Haberberger, D.; Tochitsky, S.; Gong, C.; Mori, W.; Joshi, C.; Fiuza, F.; Fonseca, R.; Silva, L.

    2011-11-01

    At the UCLA Neptune Laboratory, we have investigated laser driven ion acceleration using a high-power CO2 laser pulse in a H2 gas jet tuned around the critical plasma density of 10^19cm-3 for 10μm light. The CO2 laser pulses consist of a train of 3ps pulses separated by 18ps with a peak power of up to 4TW and total energy of 50J [1]. Protons have been accelerated from this interaction to energies up to 22MeV, which far exceeds that predicted by ponderomotive force scaling for our vacuum ao˜2. Furthermore, these high energy protons are contained within an energy spread of δE/EFWHM ˜ 1%, and have an estimated transverse emittance of down to ˜1mm.mrad. The evolution of the plasma density profile was probed with 532nm interferometry revealing a steep rise (< 10 λ) to overcritical densities followed by long exponential fall on the back side of the plasma. 2D OSIRIS simulations run with the experimentally measured plasma density profile have uncovered a multistage process for the production of monoenergetic protons based on the shock acceleration mechanism which will be discussed.[4pt][1] D. Haberberger et. al., Opt. Exp. 18, 17865 (2010)

  6. 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

  7. Changes in the salinity tolerance of sweet pepper plants as affected by nitrogen form and high CO2 concentration.

    Science.gov (United States)

    Piñero, María C; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2016-08-01

    The assimilation and availability of nitrogen in its different forms can significantly affect the response of primary productivity under the current atmospheric alteration and soil degradation. An elevated CO2 concentration (e[CO2]) triggers changes in the efficiency and efficacy of photosynthetic processes, water use and product yield, the plant response to stress being altered with respect to ambient CO2 conditions (a[CO2]). Additionally, NH4(+) has been related to improved plant responses to stress, considering both energy efficiency in N-assimilation and the overcoming of the inhibition of photorespiration at e[CO2]. Therefore, the aim of this work was to determine the response of sweet pepper plants (Capsicum annuum L.) receiving an additional supply of NH4(+) (90/10 NO3(-)/NH4(+)) to salinity stress (60mM NaCl) under a[CO2] (400μmolmol(-1)) or e[CO2] (800μmolmol(-1)). Salt-stressed plants grown at e[CO2] showed DW accumulation similar to that of the non-stressed plants at a[CO2]. The supply of NH4(+) reduced growth at e[CO2] when salinity was imposed. Moreover, NH4(+) differentially affected the stomatal conductance and water use efficiency and the leaf Cl(-), K(+), and Na(+) concentrations, but the extent of the effects was influenced by the [CO2]. An antioxidant-related response was prompted by salinity, the total phenolics and proline concentrations being reduced by NH4(+) at e[CO2]. Our results show that the effect of NH4(+) on plant salinity tolerance should be globally re-evaluated as e[CO2] can significantly alter the response, when compared with previous studies at a[CO2]. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Integrated High Temperature Coal-to-Hydrogen System with CO2 Separation

    Energy Technology Data Exchange (ETDEWEB)

    James A. Ruud; Anthony Ku; Vidya Ramaswamy; Wei Wei; Patrick Willson

    2007-05-31

    A significant barrier to the commercialization of coal-to-hydrogen technologies is high capital cost. The purity requirements for H{sub 2} fuels are generally met by using a series of unit clean-up operations for residual CO removal, sulfur removal, CO{sub 2} removal and final gas polishing to achieve pure H{sub 2}. A substantial reduction in cost can be attained by reducing the number of process operations for H{sub 2} cleanup, and process efficiency can be increased by conducting syngas cleanup at higher temperatures. The objective of this program was to develop the scientific basis for a single high-temperature syngas-cleanup module to produce a pure stream of H{sub 2} from a coal-based system. The approach was to evaluate the feasibility of a 'one box' process that combines a shift reactor with a high-temperature CO{sub 2}-selective membrane to convert CO to CO{sub 2}, remove sulfur compounds, and remove CO{sub 2} in a simple, compact, fully integrated system. A system-level design was produced for a shift reactor that incorporates a high-temperature membrane. The membrane performance targets were determined. System level benefits were evaluated for a coal-to-hydrogen system that would incorporate membranes with properties that would meet the performance targets. The scientific basis for high temperature CO{sub 2}-selective membranes was evaluated by developing and validating a model for high temperature surface flow membranes. Synthesis approaches were pursued for producing membranes that integrated control of pore size with materials adsorption properties. Room temperature reverse-selectivity for CO{sub 2} was observed and performance at higher temperatures was evaluated. Implications for future membrane development are discussed.

  9. Greenhouse gas (CO2 and CH4) emissions from a high altitude hydroelectric reservoir in the tropics (Riogrande II, Colombia)

    Science.gov (United States)

    Guérin, Frédéric; Leon, Juan

    2015-04-01

    Tropical hydroelectric reservoirs are considered as very significant source of methane (CH4) and carbon dioxide (CO2), especially when flooding dense forest. We report emissions from the Rio Grande II Reservoir located at 2000 m.a.s.l. in the Colombian Andes. The dam was built at the confluence of the Rio Grande and Rio Chico in 1990. The reservoir has a surface of 12 km2, a maximum depth of 40m and a residence time of 2.5 month. Water quality (temperature, oxygen, pH, conductivity), nitrate, ammonium, dissolved and particulate organic carbon (DOC and POC), CO2 and CH4 were monitored bi-monthly during 1.5 year at 9 stations in the reservoir. Diffusive fluxes of CO2 and CH4 and CH4 ebullition were measured at 5 stations. The Rio grande II Reservoir is weakly stratified thermally with surface temperature ranging from 20 to 24°C and a constant bottom temperature of 18°C. The reservoir water column is well oxygenated at the surface and usually anoxic below 10m depth. At the stations close to the tributaries water inputs, the water column is well mixed and oxygenated from the surface to the bottom. As reported for other reservoirs located in "clear water" watersheds, the concentrations of nutrients are low (NO3-10 mmol m-2 d-1) were observed during the dry season. Close to the tributaries water inputs where the water column is well mixed, the average diffusive flux is 8 mmol m-2 d-1. CH4 ebullition was 3.5 mmol m-2 d-1 and no ebullition was observed for a water depth higher than 5m. The zone under the influence of the water inputs from tributaries represents 25% of the surface of the reservoir but contributed half of total CH4 emissions from the reservoir (29MgC month-1). Ebullition contributed only to 12% of total CH4 emissions over a year but it contributed up to 60% during the dry season. CH4 emissions from the Rio Grande Reservoir contributed 30% of the total GHG emissions (38GgCO2eq y-1). Overall, this study show that the majority of CH4 emissions from this

  10. Recent Results in High Power CO2-Laser Cutting for Shipbuilding Industry

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Juhl, Thomas Winther; Nielsen, Jakob Skov

    2003-01-01

    In 1997 a high power laser cutting and welding test facility was established at the Danish shipyard Odense Steel Shipyard (OSS). Research and development projects were initiated in order to establish the basis for applying the full power of the laser for laser-cutting, by developing mirror based...... cutting systems. In this paper the results of these projects will be presented....

  11. Forecasting global atmospheric CO2

    Science.gov (United States)

    Agustí-Panareda, A.; Massart, S.; Chevallier, F.; Boussetta, S.; Balsamo, G.; Beljaars, A.; Ciais, P.; Deutscher, N. M.; Engelen, R.; Jones, L.; Kivi, R.; Paris, J.-D.; Peuch, V.-H.; Sherlock, V.; Vermeulen, A. T.; Wennberg, P. O.; Wunch, D.

    2014-11-01

    A new global atmospheric carbon dioxide (CO2) real-time forecast is now available as part of the pre-operational Monitoring of Atmospheric Composition and Climate - Interim Implementation (MACC-II) service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS). One of the strengths of the CO2 forecasting system is that the land surface, including vegetation CO2 fluxes, is modelled online within the IFS. Other CO2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP) system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO2 fluxes also lead to accumulating errors in the CO2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO2 fluxes compared to total optimized fluxes and the atmospheric CO2 compared to observations. The largest biases in the atmospheric CO2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO2 analyses based on the assimilation of CO2 products retrieved from satellite measurements and

  12. Effect of a high-end CO2-emission scenario on hydrology

    DEFF Research Database (Denmark)

    Karlsson, Ida Bjørnholt; Sonnenborg, Torben Obel; Seaby, Lauren Paige

    2015-01-01

    In the latest IPCC report, worst case scenarios of climate change describe average global surface warming of up to 6°C from pre-industrial times by the year 2100. This study highlights the influence of a high-end 6 degree climate change on the hydrology of a catchment in central Denmark. A simula......In the latest IPCC report, worst case scenarios of climate change describe average global surface warming of up to 6°C from pre-industrial times by the year 2100. This study highlights the influence of a high-end 6 degree climate change on the hydrology of a catchment in central Denmark...... and the less extreme RCP4.5 emission scenario are evaluated for the future period 2071−2099. The downscaled climate variables are applied to a fully distributed, physically based, coupled surface−subsurface hydrological model based on the MIKE SHE model code. The impacts on soil moisture dynamics...

  13. High-resolution data on the impact of warming on soil CO2 efflux from an Asian monsoon forest

    Science.gov (United States)

    Liang, Naishen; Teramoto, Munemasa; Takagi, Masahiro; Zeng, Jiye

    2017-01-01

    This paper describes a project for evaluation of global warming’s impacts on soil carbon dynamics in Japanese forest ecosystems. We started a soil warming experiment in late 2008 in a 55-year-old evergreen broad-leaved forest at the boundary between the subtropical and warm-temperate biomes in southern Japan. We used infrared carbon-filament heat lamps to increase soil temperature by about 2.5 °C at a depth of 5 cm and continuously recorded CO2 emission from the soil surface using a multichannel automated chamber system. Here, we present details of the experimental processes and datasets for the CO2 emission rate, soil temperature, and soil moisture from control, trenched, and warmed trenched plots. The long term of the study and its high resolution make the datasets meaningful for use in or development of coupled climate-ecosystem models to tune their dynamic behaviour as well as to provide mean parameters for decomposition of soil organic carbon to support future predictions of soil carbon sequestration. PMID:28291228

  14. Design hierarchical electrodes with highly conductive NiCo2S4 nanotube arrays grown on carbon fiber paper for high-performance pseudocapacitors.

    Science.gov (United States)

    Xiao, Junwu; Wan, Lian; Yang, Shihe; Xiao, Fei; Wang, Shuai

    2014-02-12

    We report on the development of highly conductive NiCo2S4 single crystalline nanotube arrays grown on a flexible carbon fiber paper (CFP), which can serve not only as a good pseudocapacitive material but also as a three-dimensional (3D) conductive scaffold for loading additional electroactive materials. The resulting pseudocapacitive electrode is found to be superior to that based on the sibling NiCo2O4 nanorod arrays, which are currently used in supercapacitor research due to the much higher electrical conductivity of NiCo2S4. A series of electroactive metal oxide materials, including CoxNi1-x(OH)2, MnO2, and FeOOH, were deposited on the NiCo2S4 nanotube arrays by facile electrodeposition and their pseudocapacitive properties were explored. Remarkably, the as-formed CoxNi1-x(OH)2/NiCo2S4 nanotube array electrodes showed the highest discharge areal capacitance (2.86 F cm(-2) at 4 mA cm(-2)), good rate capability (still 2.41 F cm(-2) at 20 mA cm(-2)), and excellent cycling stability (∼ 4% loss after the repetitive 2000 cycles at a charge-discharge current density of 10 mA cm(-2)).

  15. SIMULTANEOUS PRODUCTION OF HIGH-PURITY HYDROGEN AND SEQUESTRATION-READY CO2 FROM SYNGAS

    Energy Technology Data Exchange (ETDEWEB)

    Linda Denton; Hana Lorethova; Tomasz Wiltowski; Court Moorefield; Parag Kulkarni; Vladimir Zamansky; Ravi Kumar

    2003-12-01

    This final report summarizes the progress made on the program ''Simultaneous Production of High-Purity Hydrogen and Sequestration-Ready CO{sub 2} from Syngas (contract number DE-FG26-99FT40682)'', during October 2000 through September of 2003. GE Energy and Environmental Research (GE-EER) and Southern Illinois University (SIU) at Carbondale conducted the research work for this program. This program addresses improved methods to efficiently produce simultaneous streams of high-purity hydrogen and separated carbon dioxide from synthesis gas (syngas). The syngas may be produced through either gasification of coal or reforming of natural gas. The process of production of H{sub 2} and separated CO{sub 2} utilizes a dual-bed reactor and regenerator system. The reactor produces hydrogen and the regenerator produces separated CO{sub 2}. The dual-bed system can be operated under either a circulating fluidized-bed configuration or a cyclic fixed-bed configuration. Both configurations were evaluated in this project. The experimental effort was divided into lab-scale work at SIU and bench-scale work at GE-EER. Tests in a lab-scale fluidized bed system demonstrated the process for the conversion of syngas to high purity H{sub 2} and separated CO{sub 2}. The lab-scale system generated up to 95% H{sub 2} (on a dry basis). Extensive thermodynamic analysis of chemical reactions between the syngas and the fluidized solids determined an optimum range of temperature and pressure operation, where the extent of the undesirable reactions is minimum. The cycling of the process between hydrogen generation and oxygen regeneration has been demonstrated. The fluidized solids did not regenerate completely and the hydrogen purity in the reuse cycle dropped to 70% from 95% (on a dry basis). Changes in morphology and particle size may be the most dominant factor affecting the efficiency of the repeated cycling between hydrogen production and oxygen regeneration. The concept of

  16. 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.

  17. Highly Efficient Oxygen-Storage Material with Intrinsic Coke Resistance for Chemical Looping Combustion-Based CO2 Capture.

    Science.gov (United States)

    Imtiaz, Qasim; Kurlov, Alexey; Rupp, Jennifer Lilia Marguerite; Müller, Christoph Rüdiger

    2015-06-22

    Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging thermochemical CO2 capture cycles that allow the capture of CO2 with a small energy penalty. Here, the development of suitable oxygen carrier materials is a key aspect to transfer these promising concepts to practical installations. CuO is an attractive material for CLC and CLOU because of its high oxygen-storage capacity (20 wt %), fast reaction kinetics, and high equilibrium partial pressure of oxygen at typical operating temperatures (850-1000 °C). However, despite its promising characteristics, its low Tammann temperature requires the development of new strategies to phase-stabilize CuO-based oxygen carriers. In this work, we report a strategy based on stabilization by co-precipitated ceria (CeO2-x ), which allowed us to increase the oxygen capacity, coke resistance, and redox stability of CuO-based oxygen carriers substantially. The performance of the new oxygen carriers was evaluated in detail and compared to the current state-of-the-art materials, that is, Al2 O3 -stabilized CuO with similar CuO loadings. We also demonstrate that the higher intrinsic oxygen uptake, release, and mobility in CeO2-x -stabilized CuO leads to a three times higher carbon deposition resistance compared to that of Al2 O3 -stabilized CuO. Moreover, we report a high cyclic stability without phase intermixing for CeO2-x -supported CuO. This was accompanied by a lower reduction temperature compared to state-of-the-art Al2 O3 -supported CuO. As a result of its high resistance towards carbon deposition and fast oxygen uncoupling kinetics, CeO2-x -stabilized CuO is identified as a very promising material for CLC- and CLOU-based CO2 capture architectures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available The need for storage of renewable energy (RE generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel

  19. CO2-neutral fuels

    Science.gov (United States)

    Goede, A. P. H.

    2015-08-01

    The need for storage of renewable energy (RE) generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G) scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel cycle is

  20. Mesoporous carbon stabilized MgO nanoparticles synthesized by pyrolysis of MgCl2 preloaded waste biomass for highly efficient CO2 capture.

    Science.gov (United States)

    Liu, Wu-Jun; Jiang, Hong; Tian, Ke; Ding, Yan-Wei; Yu, Han-Qing

    2013-08-20

    Anthropogenic CO2 emission makes significant contribution to global climate change and CO2 capture and storage is a currently a preferred technology to change the trajectory toward irreversible global warming. In this work, we reported a new strategy that the inexhaustible MgCl2 in seawater and the abundantly available biomass waste can be utilized to prepare mesoporous carbon stabilized MgO nanoparticles (mPC-MgO) for CO2 capture. The mPC-MgO showed excellent performance in the CO2 capture process with the maximum capacity of 5.45 mol kg(-1), much higher than many other MgO based CO2 trappers. The CO2 capture capacity of the mPC-MgO material kept almost unchanged in 19-run cyclic reuse, and can be regenerated at low temperature. The mechanism for the CO2 capture by the mPC-MgO was investigated by FTIR and XPS, and the results indicated that the high CO2 capture capacity and the favorable selectivity of the as-prepared materials were mainly attributed to their special structure (i.e., surface area, functional groups, and the MgO NPs). This work would open up a new pathway to slow down global warming as well as resolve the pollution of waste biomass.

  1. Simple template fabrication of porous MnCo2O4 hollow nanocages as high-performance cathode catalysts for rechargeable Li-O2 batteries

    Science.gov (United States)

    Cao, Y. L.; Lv, F. C.; Yu, S. C.; Xu, J.; Yang, X.; Lu, Z. G.

    2016-04-01

    Porous MnCo2O4 hollow nanocages have been fabricated via a simple template method using carbon spheres as a template. The hydrophilic surface of carbon spheres can adsorb Mn2+ and Co2+ ions simultaneously to form Mn,Co-adsorbed carbon spheres. The calcination of Mn,Co-adsorbed carbon spheres can result in porous hollow nanocages of MnCo2O4. The MnCo2O4 hollow nanocages are built by nanoscale MnCo2O4 crystals. Because of the unique porous hollow nanostructures, the resulting MnCo2O4/KB cathode shows an efficient electrocatalytic performance in LiTFSI/TEGDME electrolyte-based Li-O2 batteries. The MnCo2O4 hollow nanocages as the cathode catalysts can deliver better performance during the discharge/charge processes and good cycle stability compared with that of the pure KB carbon. The preliminary results manifest that porous MnCo2O4 hollow nanocages are promising high-performance cathode catalysts for Li-O2 batteries. This template technique is a simple, general, low-cost and controllable method and can be extended to prepare other transition metal oxide hollow nanostructures.

  2. Modelling the diurnal and seasonal dynamics of soil CO2 exchange in a semiarid ecosystem with high plant–interspace heterogeneity

    Directory of Open Access Journals (Sweden)

    J. Gong

    2018-01-01

    Full Text Available We used process-based modelling to investigate the roles of carbon-flux (C-flux components and plant–interspace heterogeneities in regulating soil CO2 exchanges (FS in a dryland ecosystem with sparse vegetation. To simulate the diurnal and seasonal dynamics of FS, the modelling considered simultaneously the CO2 production, transport and surface exchanges (e.g. biocrust photosynthesis, respiration and photodegradation. The model was parameterized and validated with multivariate data measured during the years 2013–2014 in a semiarid shrubland ecosystem in Yanchi, northwestern China. The model simulation showed that soil rewetting could enhance CO2 dissolution and delay the emission of CO2 produced from rooting zone. In addition, an ineligible fraction of respired CO2 might be removed from soil volumes under respiration chambers by lateral water flows and root uptakes. During rewetting, the lichen-crusted soil could shift temporally from net CO2 source to sink due to the activated photosynthesis of biocrust but the restricted CO2 emissions from subsoil. The presence of plant cover could decrease the root-zone CO2 production and biocrust C sequestration but increase the temperature sensitivities of these fluxes. On the other hand, the sensitivities of root-zone emissions to water content were lower under canopy, which may be due to the advection of water flows from the interspace to canopy. To conclude, the complexity and plant–interspace heterogeneities of soil C processes should be carefully considered to extrapolate findings from chamber to ecosystem scales and to predict the ecosystem responses to climate change and extreme climatic events. Our model can serve as a useful tool to simulate the soil CO2 efflux dynamics in dryland ecosystems.

  3. Modelling the diurnal and seasonal dynamics of soil CO2 exchange in a semiarid ecosystem with high plant-interspace heterogeneity

    Science.gov (United States)

    Gong, Jinnan; Wang, Ben; Jia, Xin; Feng, Wei; Zha, Tianshan; Kellomäki, Seppo; Peltola, Heli

    2018-01-01

    We used process-based modelling to investigate the roles of carbon-flux (C-flux) components and plant-interspace heterogeneities in regulating soil CO2 exchanges (FS) in a dryland ecosystem with sparse vegetation. To simulate the diurnal and seasonal dynamics of FS, the modelling considered simultaneously the CO2 production, transport and surface exchanges (e.g. biocrust photosynthesis, respiration and photodegradation). The model was parameterized and validated with multivariate data measured during the years 2013-2014 in a semiarid shrubland ecosystem in Yanchi, northwestern China. The model simulation showed that soil rewetting could enhance CO2 dissolution and delay the emission of CO2 produced from rooting zone. In addition, an ineligible fraction of respired CO2 might be removed from soil volumes under respiration chambers by lateral water flows and root uptakes. During rewetting, the lichen-crusted soil could shift temporally from net CO2 source to sink due to the activated photosynthesis of biocrust but the restricted CO2 emissions from subsoil. The presence of plant cover could decrease the root-zone CO2 production and biocrust C sequestration but increase the temperature sensitivities of these fluxes. On the other hand, the sensitivities of root-zone emissions to water content were lower under canopy, which may be due to the advection of water flows from the interspace to canopy. To conclude, the complexity and plant-interspace heterogeneities of soil C processes should be carefully considered to extrapolate findings from chamber to ecosystem scales and to predict the ecosystem responses to climate change and extreme climatic events. Our model can serve as a useful tool to simulate the soil CO2 efflux dynamics in dryland ecosystems.

  4. High resolution fossil fuel combustion CO2 emission fluxes for the United States

    Energy Technology Data Exchange (ETDEWEB)

    Gurney, Kevin R.; Mendoza, Daniel L.; Zhou, Yuyu; Fischer, Marc L.; Miller, Chris C.; Geethakumar, Sarath; de la Rue du Can, Stephane

    2009-03-19

    Quantification of fossil fuel CO{sub 2} emissions at fine space and time resolution is emerging as a critical need in carbon cycle and climate change research. As atmospheric CO{sub 2} measurements expand with the advent of a dedicated remote sensing platform and denser in situ measurements, the ability to close the carbon budget at spatial scales of {approx}100 km{sup 2} and daily time scales requires fossil fuel CO{sub 2} inventories at commensurate resolution. Additionally, the growing interest in U.S. climate change policy measures are best served by emissions that are tied to the driving processes in space and time. Here we introduce a high resolution data product (the 'Vulcan' inventory: www.purdue.edu/eas/carbon/vulcan/) that has quantified fossil fuel CO{sub 2} emissions for the contiguous U.S. at spatial scales less than 100 km{sup 2} and temporal scales as small as hours. This data product, completed for the year 2002, includes detail on combustion technology and 48 fuel types through all sectors of the U.S. economy. The Vulcan inventory is built from the decades of local/regional air pollution monitoring and complements these data with census, traffic, and digital road data sets. The Vulcan inventory shows excellent agreement with national-level Department of Energy inventories, despite the different approach taken by the DOE to quantify U.S. fossil fuel CO{sub 2} emissions. Comparison to the global 1{sup o} x 1{sup o} fossil fuel CO{sub 2} inventory, used widely by the carbon cycle and climate change community prior to the construction of the Vulcan inventory, highlights the space/time biases inherent in the population-based approach.

  5. An improved method of high-precision determination of Δ(17)O of CO2 by catalyzed exchange with O2 using hot platinum.

    Science.gov (United States)

    Mahata, Sasadhar; Bhattacharya, S K; Liang, Mao-Chang

    2016-01-15

    CO2 and O2 can exchange their oxygen isotopes rapidly in the presence of hot (~670 °C) platinum and this has led to a method for determining the δ(17)O value of a CO2 sample. We have improved the method to achieve a precision of 0.008 ‰ (1-σ standard deviation) in the determination of δ(17)O values. Such high precision is essential to identify the stratospheric component in tropospheric CO2 and use it for global carbon flux studies. The crucial issue in the accurate determination of the δ(17)O value is estimation of a correction factor, which depends on the amount ratio CO2/O2. An attempt was also made to investigate the mechanism of exchange with their controlling parameters. The oxygen isotopes of a CO2 sample gas are exchanged with those of an appropriate amount of tank O2 in the presence of hot platinum. The pre-exchange CO2 and O2 gas samples as well as the post-exchange O2 sample are analyzed by isotope ratio mass spectrometry. A mixing model was developed involving the δ(18)O value of the CO2 and δ(17)O and δ(18)O values of pre- and post-exchange O2 to obtain the δ(17)O value of the CO2 sample. A correction to the measured value was determined to obtain the actual value with high accuracy and precision. To obtain a precision better than 0.01 ‰ requires the amount ratio CO2/O2 to be controlled to better than ~15 %. We also find that the oxygen isotopes are nearly homogeneously distributed between the O2 and the CO2 molecules. In addition, determination of the (16) O(13)C(18)O/(16)O(12)C(16)O isotopologue ratio in the CO2 shows that the abundance of (16)O(13)C(18)O is close to that expected for random partitioning of the isotopes among the CO2 isotopologues. The isotopic scrambling between O2 and CO2 that occurs on hot platinum allows one to accurately determine the δ(17)O values of CO2 through isotopic analysis of O2. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Using TOUGH2/ECO2H for modeling high-pressure and high-temperature CO2-enhanced geothermal energy extraction from saline systems

    Science.gov (United States)

    Borgia, A.; Pruess, K.; Kneafsey, T. J.; Oldenburg, C. M.

    2011-12-01

    Conventional geothermal energy uses water as the fluid to transport heat to the surface. This has a number of drawbacks principally related to strong water-rock chemical reactions, but also in terms of environmental impacts through overdraft of shallow aquifers with valuable water resources. Various authors have proposed the use of CO2 instead of water to transfer heat because such use may result in better rate of heat extraction, less fluid-rock reactivity, and less demand for scarce ground or surface water resources. TOUGH2/ECO2H was developed to study the behavior of high-pressure high-temperature H2O-CO2-NaCl geothermal systems. To demonstrate and test the code, we have modeled an idealized fractured geothermal system. Based on a five-spot well pattern and its inherent symmetry, we use a model grid of 1/8 of a square with sides of 1 km. In the model, CO2 is injected at the four corner-wells at 20 °C and constant pressure of 2.1*10^7 Pa into a variable salinity reservoir which is initially at 200 °C. The center well produces fluid at a constant pressure of 1.9*10^7 Pa. Initially, H2O + NaCl are produced, followed by a mixture of H2O + CO2 + NaCl and, finally only CO2. As soon as the injected CO2 reaches the production well, usually less than 2 months after injection begins, there is a drastic drop in heat production. This decrease occurs because of a reduced flow rate induced by reduction in effective permeability associated with two-phase flow (liquid + gas) in the reservoir. As the liquid phase dries out, the CO2 flow rate increases slowly over about 2-3 years and the heat production reaches a maximum rate that is about 40% larger than the initial rate of production with just water. Our modeling suggests that this same behavior occurs for highly saline geothermal reservoirs, even though the absolute rate of heat production is about 30% lower than the non-saline models. The decrease in production for saline systems is due to a marked reduction in permeability

  7. Preliminary investigation into laser high voltage interaction in the case of streamer-to-leader process using a high power CO 2 laser

    CSIR Research Space (South Africa)

    West, NJ

    2006-01-01

    Full Text Available This paper describes the preliminary small-scale experiments conducted in order to investigate the influence of intensely focused laser light produced by a CO 2 laser on high voltage fields. The laser used operated at a maximum energy of 430 mJ per...

  8. First Spectroscopic Identification of Pyrocarbonate for High CO2 Flux Membranes Containing Highly Interconnected Three Dimensional Ionic Channels

    Science.gov (United States)

    2013-01-01

    the CO2/MC interface and internal ionic transfer at 2PBs of the SDC /MC interface. The species C2O5 2 (pyrocarbonate or dicarbonate anion) possessing a...C2O5(MC) 2 (3) Once formed, C2O5 2 can immediately react with O2 available at the SDC /MC interface, dissociating into two CO3 2 that can...3PBs to 2PBs in dual-phase MOCC membranes; SDC = Sm2O3-doped CeO2; MC = molten carbonate. Fig. 2 Equilibrium geometry of the C2O5 2 species. The unit of

  9. Long term effects of forest fires to soil C content and soil CO_{2} efflux in hemiboreal Scots pine forests of Estonia.

    Science.gov (United States)

    Köster, Kajar; Metslaid, Marek; Orumaa, Argo; Parro, Kristi; Jõgiste, Kalev; Berninger, Frank; Pumpanen, Jukka; Köster, Egle

    2016-04-01

    Fire is the primary process which organizes the physical and biological attributes of the boreal biome and influences energy flows and biogeochemical cycles, particularly the carbon (C) cycle. Especially the soil organic matter pool in boreal forests is an important C storage with a long C turnover time, but fire frequencies that are expected to increase with changing climate, can change that. We compared the initial recovery of C pools and CO2 efflux following fire disturbances in Scots pine (Pinus sylvesteris L.) stands with different time since fire. The study areas are located in hemiboreal vegetation zone, in northwestern Estonia, in Vihterpalu. Six areas (with extensive fires 200 ha and more) were chosen for study: fire in a year 1837, 1940, 1951, 1982, 1997, and 2008. In all areas we are dealing with stand replacing fires where all (or almost all) of the stand was destroyed by fire. On every area we established three permanent sample plots. Soil respiration was measured manually from all sample plots (measuring interval of two - three weeks). Manual chamber measurements are performed on 5 collars (north - south orientated and the distance between collars is 5 m) at each sample plot from May till November 2015. To characterize the soil C and N content and fine root biomass at the sites, 5 soil cores (0.5 m long and 0.05 m in diameter) were taken from each sample plot. Our results show that forest fire has a substantial effect on the C content in the top soil layer, but not in the humus layer and in mineral soil layers. Soil respiration showed similar chronological response to the time since the forest fire indicating that substantial proportion of the respiration was originating from the very top of the soil. Soil respiration values were lowest on the area where the fire was in a year 2008 and the respiration values followed also seasonal pattern being highest in August and lowest in May and November. The CO2 effluxes were lowest on newly burned area through

  10. A porous Cd(II) metal-organic framework with high adsorption selectivity for CO2 over CH4

    Science.gov (United States)

    Zhu, Chunlan

    2017-05-01

    Metal-organic frameworks (MOFs) have attracted a lot of attention in recent decades. We applied a semi-rigid four-carboxylic acid linker to assemble with Cd(II) ions to generate a novel microporous Cd(II) MOF material. Single crystal X-ray diffraction study reveals the different two dimension (2D) layers can be further packed together with an AB fashion by hydrogen bonds (O4sbnd H4⋯O7 = 1.863 Å) to construct a three dimension (3D) supermolecular architecture. The resulting sample can be synthesized under solvothermal reactions successfully, which exhibits high selectivity adsorption of CO2 over CH4 at room temperature. In addition, the obtained sample was characterized by thermal gravimetric analyses (TGA), Fourier-transform infrared spectra (FT-IR), elemental analysis (CHN) and powder X-ray diffraction (PXRD).

  11. Hierarchical Mesoporous 3D Flower-like CuCo2O4/NF for High-Performance Electrochemical Energy Storage

    National Research Council Canada - National Science Library

    Jadhav, Harsharaj S; Pawar, Sambhaji M; Jadhav, Arvind H; Thorat, Gaurav M; Seo, Jeong Gil

    2016-01-01

    Ternary spinel CuCo2O4 nanostructure clenches great potential as high-performance electrode material for next-generation energy storage systems because of its higher electrical conductivity and electrochemical activity...

  12. Coccolithophores in a High CO2 World: Long-Term Trends and Rapid Events in the Paleogene

    Science.gov (United States)

    Dunkley Jones, T.; Bown, P. R.; Maslin, M. A.

    2008-12-01

    Predicting the response of the calcareous phytoplankton to increased sea surface temperatures and ocean acidity has provoked extensive debate amongst biologists, oceanographers and micropaleontologists, with attention focusing on coccolithophore culture experiments and extreme climate events in the geological record such as the Paleocene/Eocene thermal maximum (PETM). Less attention has been directed at understanding the long-term macroevolutionary response of coccolithophores to high pCO2 warm-climate states or to rapid cooling events in earth history. The Paleogene epoch encompasses many of the key intervals of Cenozoic coccolithophore evolution and is ideally suited to an assessment of both the long-term impact of a high pCO2 warm-climate state on coccolithophore macroevolution and the effects of the most significant rapid warming (PETM) and cooling events (Eocene/Oligocene Transition; EOT) of the Cenozoic. Here we present records of the coccolithophore response to both the PETM and EOT from the Kilwa Group calcareous microfossil Konservat-Lagerstätte of southern Tanzania. Through all the intervals studied the calcareous nannoplankton recovered from these sediments are more diverse than any previously documented sections of the same age and include many small and fragile taxa that are new to science. In the Tanzanian sections the onset of the PETM is marked by rapid and significant nannoplankton assemblage shifts and synchronous extinctions representing around 10% of the total diversity, indicative of a severe disruption of the photic zone environment. Nannofossil assemblage data across the EOT reveal a significant drop in diversity and the abundance of oligotrophic taxa directly coincident with global cooling, indicating a significant increase in nutrient availability in the low-latitude surface ocean. These two rapid climatic events bound the Eocene epoch and we discuss the connections between coccolithophore macroevolution and Eocene climate and the critical

  13. A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

    KAUST Repository

    Eddaoudi, Mohamed

    2015-07-06

    The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.

  14. Synthesis of highly efficient CaO-based, self-stabilizing CO2 sorbents via structure-reforming of steel slag.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo; Yan, Feng; Li, Kaimin; Chen, Xuejing

    2015-06-16

    Capturing anthropogenic CO2 in a cost-effective and highly efficient manner is one of the most challenging issues faced by scientists today. Herein, we report a novel structure-reforming approach to convert steel slag, a cheap, abundant, and nontoxic calcium-rich industrial waste, as the only feedstock into superior CaO-based, self-stabilizing CO2 sorbents. The CO2 capture capacity of all the steel slag-derived sorbents was improved more than 10-fold compared to the raw slag, with the maximum uptake of CO2 achieving at 0.50 gCO2 gsorbent(-1). Additionally, the initial steel slag-derived sorbent could retain 0.25 gCO2 gsorbent(-1), that is, a decay rate of only 12% over 30 carbonation-calcination cycles, the excellent self-stabilizing property allowed it to significantly outperform conventional CaO, and match with most of the existing synthetic CaO-based sorbents. A synergistic effect that facilitated CO2 capture by CaO-based sorbents was clearly recognized when Mg and Al, the most common elements in steel slag, coexisted with CaO in the forms of MgO and Al2O3, respectively. During the calcium looping process, MgO served as a well spacer to increase the porosity of sorbents together with Al2O3 serving as a durable stabilizer to coresist the sintering of CaCO3 grains at high temperatures.

  15. Construction of a Hierarchical NiCo2S4@PPy Core-Shell Heterostructure Nanotube Array on Ni Foam for a High-Performance Asymmetric Supercapacitor.

    Science.gov (United States)

    Yan, Minglei; Yao, Yadong; Wen, Jiqiu; Long, Lu; Kong, Menglai; Zhang, Guanggao; Liao, Xiaoming; Yin, Guangfu; Huang, Zhongbing

    2016-09-21

    In this paper, a hierarchical NiCo2S4@polypyrrole core-shell heterostructure nanotube array on Ni foam (NiCo2S4@PPy/NF) was successfully developed as a bind-free electrode for supercapacitors. NiCo2S4@PPy-50/NF obtained under 50 s PPy electrodeposition shows a low charge-transfer resistance (0.31 Ω) and a high area specific capacitance of 9.781 F/cm(2) at a current density of 5 mA/cm(2), which is two times higher than that of pristine NiCo2S4/NF (4.255 F/cm(2)). Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4@PPy-50/NF as positive electrode and activated carbon (AC) as negative electrode. The resulting NiCo2S4@PPy-50/NF//AC device exhibits a high energy density of 34.62 Wh/kg at a power density of 120.19 W/kg with good cycling performance (80.64% of the initial capacitance retention at 50 mA/cm(2) over 2500 cycles). The superior electrochemical performance can be attributed to the combined contribution of both component and unique core-shell heterostructure. The results demonstrate that the NiCo2S4@PPy-50 core-shell heterostructure nanotube array is promising as electrode material for supercapacitors in energy storage.

  16. Formate-Dependent Microbial Conversion of CO2 and the Dominant Pathways of methanogenesis in production water of high-temperature oil reservoirs amended with bicarbonate

    Directory of Open Access Journals (Sweden)

    Guang-Chao eYang

    2016-03-01

    Full Text Available CO2 sequestration in deep-subsurface formations including oil reservoirs is a potential measure to reduce the CO2 concentration in the atmosphere. However, the fate of the CO2 and the ecological influences in Carbon Dioxide Capture and Storage (CDCS facilities is not understood clearly. In the current study, the fate of CO2 (in bicarbonate form (0~90 mM with 10 mM of formate as electron donor and carbon source was investigated with high-temperature production water from oilfield in China. The isotope data showed that bicarbonate could be reduced to methane by methanogens and major pathway of methanogenesis could be syntrophic formate oxidation coupled with CO2 reduction and formate methanogenesis under the anaerobic conditions. The bicarbonate addition induced the shift of microbial community. Addition of bicarbonate and formate was associated with a decrease of Methanosarcinales, but promotion of Methanobacteriales in all treatments. Thermodesulfovibrio was the major group in all the samples and Thermacetogenium dominated in the high bicarbonate treatments. The results indicated that CO2 from CDCS could be transformed to methane and the possibility of microbial CO2 conversion for enhanced microbial energy recovery in oil reservoirs.

  17. High CO2 atmosphere modulating the phenolic response associated with cell adhesion and hardening of Annona cherimola fruit stored at chilling temperature.

    Science.gov (United States)

    Maldonado, Roberto; Molina-Garcia, Antonio D; Sanchez-Ballesta, Maria T; Escribano, Maria I; Merodio, Carmen

    2002-12-18

    Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5.) activity, tanning ability, and polyphenols levels were measured in cherimoya (Annona cherimola Mill.) fruit treated with 20% CO(2) + 20% O(2) + 60% N(2) for 1, 3, or 6 days during chilling temperature (6 degrees C) storage. The residual effect of CO(2) after transfer to air was also studied. These observations were correlated with texture and cellular characteristics, visualized by cryo-SEM. Tanning ability and the early increase in tannin polyphenols induced by chilling temperature were reduced by CO(2) treatment. Conversely, high CO(2) atmosphere enhanced the nontannin polyphenol fraction as compared with fruit stored in air. Lignin accumulation and PAL activation observed in untreated fruit after prolonged storage at chilling temperature were prevented by high CO(2). Moreover, the restraining effect on lignification was less effective when the CO(2) treatment was prolonged for 6 days. In addition, fruits held at these conditions had greater firmness and the histological characterization of the separation between cells was similar to that in untreated fruits. We conclude that CO(2) treatment modulates the phenolic response that seems to regulate the strength of cell adhesion and so to prevent hardening caused by chilling temperature storage.

  18. CuCo2O4 nanoplate film as a low-cost, highly active and durable catalyst towards the hydrolytic dehydrogenation of ammonia borane for hydrogen production

    Science.gov (United States)

    Liu, Quanbing; Zhang, Shengjie; Liao, Jinyun; Feng, Kejun; Zheng, Yuying; Pollet, Bruno G.; Li, Hao

    2017-07-01

    Catalytic dehydrogenation of ammonia borane is one of the most promising routes for the production of clean hydrogen as it is seen as a highly efficient and safe method. However, its large-scale industrial application is either limited by the high cost of the catalyst (usually a noble metal based catalyst) or by the low activity and poor reusability (usually a non-noble metal catalyst). In this study, we have successfully prepared three low-cost CuCo2O4 nanocatalysts, namely: (i) Ti supported CuCo2O4 film made of CuCo2O4 nanoplates, (ii) Ti supported CuCo2O4 film made of CuCo2O4 nanosheets, and (iii) unsupported CuCo2O4 nanoparticles. Among the three catalysts used for the hydrolytic dehydrogeneration of ammonia borane, the CuCo2O4 nanoplate film exhibits the highest catalytic activity with a turnover frequency (TOF) of ∼44.0 molhydrogen min-1 molcat-1. This is one of the largest TOF value for noble-metal-free catalysts ever reported in the literature. Moreover, the CuCo2O4 nanoplate film almost keeps its original catalytic activity after eight cycles, indicative of its high stability and good reusability. Owing to its advantages, the CuCo2O4 nanoplate film can be a promising catalyst for the hydrolytic dehydrogenation of ammonia borane, which may find important applications in the field of hydrogen energy.

  19. Photosynthesis of Scenedesmus obliquus in outdoor open thin-layer cascade system in high and low CO2 in Belgium.

    Science.gov (United States)

    de Marchin, Thomas; Erpicum, Michel; Franck, Fabrice

    2015-12-10

    Two outdoor open thin-layer cascade systems operated as batch cultures with the alga Scenedesmus obliquus were used to compare the productivity and photosynthetic acclimations in control and CO2 supplemented cultures in relation with the outdoor light irradiance. We found that the culture productivity was limited by CO2 availability. In the CO2 supplemented culture, we obtained a productivity of up to 24gdwm(-2)day(-1) and found a photosynthetic efficiency (value based on the PAR solar radiation energy) of up to 5%. In the CO2 limited culture, we obtained a productivity of up to 10gdwm(-2)day(-1) while the photosynthetic efficiency was up to 3.3% and decreased to 2.1% when the integrated daily PAR increased. Fluorescence and oxygen evolution measurements showed that ETR and oxygen evolution light saturation curves, as well as light-dependent O2 uptake were similar in algal samples from both cultures when the CO2 limitation was removed. In contrast, we found that CO2 limitation conducted to a decreased PSII photochemical efficiency and an increased light-induced heat-dissipation in the control culture compared to the CO2 supplemented culture. These features are in line with a lower light use efficiency and may therefore contribute to the lower productivity observed in absence of CO2 supplementation in outdoor mass cultures of S. obliquus. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Zeolite Rho: a highly selective adsorbent for CO2/CH4 separation induced by a structural phase modification.

    Science.gov (United States)

    Palomino, Miguel; Corma, Avelino; Jordá, Jose L; Rey, Fernando; Valencia, Susana

    2012-01-07

    Zeolite Rho is able to successfully separate CO(2) from CH(4) with the highest selectivity ever observed on the basis of pore diameter and surface polarity. The adsorption of CO(2) provokes structural changes in the zeolite Rho. This journal is © The Royal Society of Chemistry 2012

  1. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    Science.gov (United States)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  2. A Triazole-Containing Metal-Organic Framework as a Highly Effective and Substrate Size-Dependent Catalyst for CO2 Conversion.

    Science.gov (United States)

    Li, Pei-Zhou; Wang, Xiao-Jun; Liu, Jia; Lim, Jie Sheng; Zou, Ruqiang; Zhao, Yanli

    2016-02-24

    A highly porous metal-organic framework (MOF) incorporating both exposed metal sites and nitrogen-rich triazole groups was successfully constructed via solvothermal assembly of a clicked octcarboxylate ligand and Cu(II) ions, which presents a high affinity toward CO2 molecules clearly verified by gas adsorption and Raman spectral detection. The constructed MOF featuring CO2-adsorbing property and exposed Lewis-acid metal sites could serve as an excellent catalyst for CO2-based chemical fixation. Catalytic activity of the MOF was confirmed by remarkably high efficiency on CO2 cycloaddition with small epoxides. When extending the substrates to larger ones, its activity showed a sharp decrease. These observations reveal that MOF-catalyzed CO2 cycloaddition of small substrates was carried out within the framework, while large ones cannot easily enter into the porous framework for catalytic reactions. Thus, the synthesized MOF exhibits high catalytic selectivity to different substrates on account of the confinement of the pore diameter. The high efficiency and size-dependent selectivity toward small epoxides on catalytic CO2 cycloaddition make this MOF a promising heterogeneous catalyst for carbon fixation.

  3. Combining an automated closed chamber system with a quantum cascade laser for high-frequency measurements of δ13C of ecosystem CO2 fluxes

    Science.gov (United States)

    Brændholt, Andreas; Ibrom, Andreas; Ambus, Per; Steenberg Larsen, Klaus; Pilegaard, Kim

    2017-04-01

    Advances in laser spectroscopy have allowed for online high-frequency measurements of the isotopic composition of C and O in CO2, thereby providing new ways to investigate CO2 flux partitioning and carbon cycling in natural ecosystems. In this study, we combined an Aerodyne quantum cascade laser for CO2 isotopes with the LI-COR LI-8100A/8150 automatic closed chamber system to yield the δ13C of CO2 during automated closed chamber measurements. The system was used during a two month campaign in a Danish beech forest, where δ13C was measured for a total of 12 chambers, each enclosing either intact soil, trenched soil, tree stem or a tree root. By applying the Keeling plot methodology to the change in δ13C of CO2 during a chamber measurement, the isotopic composition of the respired CO2 was determined. The poster presents δ13C data of ecosystem CO2 fluxes on both a daily and diel scale for soil, roots and tree stems that revealed interesting information about forest ecosystem carbon cycling. Furthermore, it explores the unique setup and the tests required for precise automated chamber-based measurements of δ13C by a quantum cascade laser. Acknowledgements: This study was funded by the free Danish Ministry for Research, Innovation and higher Education, the free Danish Research Council (DFF - 1323-00182).

  4. Tuning of ZIF-Derived Carbon with High Activity, Nitrogen Functionality, and Yield - A Case for Superior CO2 Capture.

    Science.gov (United States)

    Gadipelli, Srinivas; Guo, Zheng Xiao

    2015-06-22

    A highly effective and facile synthesis route is developed to create and tailor metal-decorated and nitrogen-functionalized active microporous carbon materials from ZIF-8. Clear metal- and pyrrolic-N-induced enhancements of the cyclic CO2 uptake capacities and binding energies are achieved, particularly at a much lower carbonization temperature of 700 °C than those often reported (1000 °C). The high-temperature carbonization can enhance the porosity but only at the expense of considerable losses of sample yield and metal and N functional sites. The findings are comparatively discussed with carbons derived from metal-organic frameworks (MOFs) reported previously. Furthermore, the porosity of the MOF-derived carbon is critically dependent on the structure of the precursor MOF and the crystal growth. The current strategy offers a new and effective route for the creation and tuning of highly active and functionalized carbon structures in high yields and with low energy consumption. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  5. Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency

    Science.gov (United States)

    Monje, O.; Bugbee, B.

    1998-01-01

    The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 micromoles mol-1 [CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102.8 +/- 4.7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P < 0.05) and root respiration (24%, P < 0.05). These data indicate that plant communities adapt to CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.

  6. Edge-functionalized nanoporous carbons for high adsorption capacity and selectivity of CO2 over N2

    Science.gov (United States)

    Zhou, Sainan; Guo, Chen; Wu, Zhonghua; Wang, Maohuai; Wang, Zhaojie; Wei, Shuxian; Li, Shaoren; Lu, Xiaoqing

    2017-07-01

    Single-component adsorption and competitive behavior of binary CO2/N2 mixture in the edge-functionalized nanoporous carbons (NPCs) were investigated by grand canonical Monte Carlo simulation. Results demonstrated that edge-functionalization effectively improved the pore topology and morphological characteristics of NPCs. Evaluation of adsorption capacity and analyses of the isosteric heat and radial distribution functions confirmed that edge-functionalization can evidently enhance the single-component adsorption of CO2/N2. Temperature had a negative effect on the single-component adsorption of CO2/N2 whereas pressure had a positive effect before adsorption reaches a stable equilibrium state. Edge-functionalization can significantly increase the selectivity of CO2 over N2 in NPCs, which demonstrate the following sequence according to selectivity: NH2sbnd NPC > COOHsbnd NPC > OHsbnd NPC > Hsbnd NPC > NPC. The increased CO2 molar fraction in the binary CO2/N2 mixture decreased the selectivity and saturation pressure to reach a stable equilibrium state. Overall, this work highlighted the effects of edge-functionalization on the adsorption and separation of CO2/N2 in NPCs, and provided an effective strategy for designing and screening adsorbent materials for carbon capture and separation.

  7. Increasing summer net CO2 uptake in high northern ecosystems inferred from atmospheric inversions and comparisons to remote-sensing NDVI

    Science.gov (United States)

    Welp, Lisa R.; Patra, Prabir K.; Rödenbeck, Christian; Nemani, Rama; Bi, Jian; Piper, Stephen C.; Keeling, Ralph F.

    2016-07-01

    Warmer temperatures and elevated atmospheric CO2 concentrations over the last several decades have been credited with increasing vegetation activity and photosynthetic uptake of CO2 from the atmosphere in the high northern latitude ecosystems: the boreal forest and arctic tundra. At the same time, soils in the region have been warming, permafrost is melting, fire frequency and severity are increasing, and some regions of the boreal forest are showing signs of stress due to drought or insect disturbance. The recent trends in net carbon balance of these ecosystems, across heterogeneous disturbance patterns, and the future implications of these changes are unclear. Here, we examine CO2 fluxes from northern boreal and tundra regions from 1985 to 2012, estimated from two atmospheric inversions (RIGC and Jena). Both used measured atmospheric CO2 concentrations and wind fields from interannually variable climate reanalysis. In the arctic zone, the latitude region above 60° N excluding Europe (10° W-63° E), neither inversion finds a significant long-term trend in annual CO2 balance. The boreal zone, the latitude region from approximately 50-60° N, again excluding Europe, showed a trend of 8-11 Tg C yr-2 over the common period of validity from 1986 to 2006, resulting in an annual CO2 sink in 2006 that was 170-230 Tg C yr-1 larger than in 1986. This trend appears to continue through 2012 in the Jena inversion as well. In both latitudinal zones, the seasonal amplitude of monthly CO2 fluxes increased due to increased uptake in summer, and in the arctic zone also due to increased fall CO2 release. These findings suggest that the boreal zone has been maintaining and likely increasing CO2 sink strength over this period, despite browning trends in some regions and changes in fire frequency and land use. Meanwhile, the arctic zone shows that increased summer CO2 uptake, consistent with strong greening trends, is offset by increased fall CO2 release, resulting in a net neutral

  8. Increasing summer net CO2 uptake in high northern ecosystems inferred from atmospheric inversions and comparisons to remote-sensing NDVI

    Directory of Open Access Journals (Sweden)

    L. R. Welp

    2016-07-01

    Full Text Available Warmer temperatures and elevated atmospheric CO2 concentrations over the last several decades have been credited with increasing vegetation activity and photosynthetic uptake of CO2 from the atmosphere in the high northern latitude ecosystems: the boreal forest and arctic tundra. At the same time, soils in the region have been warming, permafrost is melting, fire frequency and severity are increasing, and some regions of the boreal forest are showing signs of stress due to drought or insect disturbance. The recent trends in net carbon balance of these ecosystems, across heterogeneous disturbance patterns, and the future implications of these changes are unclear. Here, we examine CO2 fluxes from northern boreal and tundra regions from 1985 to 2012, estimated from two atmospheric inversions (RIGC and Jena. Both used measured atmospheric CO2 concentrations and wind fields from interannually variable climate reanalysis. In the arctic zone, the latitude region above 60° N excluding Europe (10° W–63° E, neither inversion finds a significant long-term trend in annual CO2 balance. The boreal zone, the latitude region from approximately 50–60° N, again excluding Europe, showed a trend of 8–11 Tg C yr−2 over the common period of validity from 1986 to 2006, resulting in an annual CO2 sink in 2006 that was 170–230 Tg C yr−1 larger than in 1986. This trend appears to continue through 2012 in the Jena inversion as well. In both latitudinal zones, the seasonal amplitude of monthly CO2 fluxes increased due to increased uptake in summer, and in the arctic zone also due to increased fall CO2 release. These findings suggest that the boreal zone has been maintaining and likely increasing CO2 sink strength over this period, despite browning trends in some regions and changes in fire frequency and land use. Meanwhile, the arctic zone shows that increased summer CO2 uptake, consistent with strong greening trends, is offset by

  9. 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.

  10. High temporal resolution ecosystem CH4, CO2 and H2O flux data measured with a novel chamber technique

    Science.gov (United States)

    Steenberg Larsen, Klaus; Riis Christiansen, Jesper

    2016-04-01

    switching automatically between transparent and darkened mode enabling for separation of light-sensitive and light-indifferent processes in chambers. In a pilot study we measured hourly fluxes of CO2, H2O and CH4 continuously for two weeks in Danish Calluna vulgaris (common heather) heathland (Larsen et al. 2011). We will present an analysis of the novel, high-frequency data of CH4 fluxes under light and dark conditions, assess the advantages and limitations of the experimental setup and recommend future improvements of the technology involved. References: Carter, M.S., Larsen, K.S., et al. 2012. Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands: responses to climatic and environmental changes. Biogeosciences 3739-3755. Christiansen, J.R., Korhonen, J.F.J., et al. 2011. Assessing the effects of chamber placement, manual sampling and headspace mixing on CH4 fluxes in a laboratory experiment. Plant and Soil 343, 171-185. Christiansen, J.R., Outhwaite, J., et al. 2015. Comparison of CO2, CH4 and N2O soil-atmosphere exchange measured in static chambers with cavity ring-down spectroscopy and gas chromatography. Agricultural and Forest Meteorology 211-212, 48-57. Creelman, C., Nickerson, N., Risk, D., 2013. Quantifying Lateral Diffusion Error in Soil Carbon Dioxide Respiration Estimates using Numerical Modeling. Soil Science Society of America Journal 77, 699-708. Larsen, K.S., Andresen, L.C., et al. 2011. Reduced N cycling in response to elevated CO2, warming, and drought in a Danish heathland: Synthesizing results of the CLIMAITE project after two years of treatments. Global Change Biology 17, 1884-1899. Pihlatie, M.K., Christiansen, J.R., et al. 2013. Comparison of static chambers to measure CH4 emissions from soils. Agricultural and Forest Meteorology 171-172, 124-136.

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

    Science.gov (United States)

    Ohtomo, Yoko; Ijiri, Akira; Ikegawa, Yojiro; Tsutsumi, Masazumi; Imachi, Hiroyuki; Uramoto, Go-Ichiro; Hoshino, Tatsuhiko; Morono, Yuki; Sakai, Sanae; Saito, Yumi; Tanikawa, Wataru; Hirose, Takehiro; Inagaki, Fumio

    2013-01-01

    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 δ(13)Cacetate, 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 acetate.

  12. 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

  13. Larvae of the coral eating crown-of-thorns starfish, Acanthaster planci in a warmer-high CO2 ocean.

    Science.gov (United States)

    Kamya, Pamela Z; Dworjanyn, Symon A; Hardy, Natasha; Mos, Benjamin; Uthicke, Sven; Byrne, Maria

    2014-11-01

    Outbreaks of crown-of-thorns starfish (COTS), Acanthaster planci, contribute to major declines of coral reef ecosystems throughout the Indo-Pacific. As the oceans warm and decrease in pH due to increased anthropogenic CO2 production, coral reefs are also susceptible to bleaching, disease and reduced calcification. The impacts of ocean acidification and warming may be exacerbated by COTS predation, but it is not known how this major predator will fare in a changing ocean. Because larval success is a key driver of population outbreaks, we investigated the sensitivities of larval A. planci to increased temperature (2-4 °C above ambient) and acidification (0.3-0.5 pH units below ambient) in flow-through cross-factorial experiments (3 temperature × 3 pH/pCO2 levels). There was no effect of increased temperature or acidification on fertilization or very early development. Larvae reared in the optimal temperature (28 °C) were the largest across all pH treatments. Development to advanced larva was negatively affected by the high temperature treatment (30 °C) and by both experimental pH levels (pH 7.6, 7.8). Thus, planktonic life stages of A. planci may be negatively impacted by near-future global change. Increased temperature and reduced pH had an additive negative effect on reducing larval size. The 30 °C treatment exceeded larval tolerance regardless of pH. As 30 °C sea surface temperatures may become the norm in low latitude tropical regions, poleward migration of A. planci may be expected as they follow optimal isotherms. In the absence of acclimation or adaptation, declines in low latitude populations may occur. Poleward migration will be facilitated by strong western boundary currents, with possible negative flow-on effects on high latitude coral reefs. The contrasting responses of the larvae of A. planci and those of its coral prey to ocean acidification and warming are considered in context with potential future change in tropical reef ecosystems.

  14. Nucleotide pyrophosphatase/phosphodiesterase 1 exerts a negative effect on starch accumulation and growth in rice seedlings under high temperature and CO2 concentration conditions.

    Science.gov (United States)

    Kaneko, Kentaro; Inomata, Takuya; Masui, Takahiro; Koshu, Tsutomu; Umezawa, Yukiho; Itoh, Kimiko; Pozueta-Romero, Javier; Mitsui, Toshiaki

    2014-02-01

    Nucleotide pyrophosphatase/phosphodiesterase (NPP) is a widely distributed enzymatic activity occurring in both plants and mammals that catalyzes the hydrolytic breakdown of the pyrophosphate and phosphodiester bonds of a number of nucleotides. Unlike mammalian NPPs, the physiological function of plant NPPs remains largely unknown. Using a complete rice NPP1-encoding cDNA as a probe, in this work we have screened a rice shoot cDNA library and obtained complete cDNAs corresponding to six NPP genes (NPP1-NPP6). As a first step to clarify the role of NPPs, recombinant NPP1, NPP2 and NPP6 were purified from transgenic rice cells constitutively expressing NPP1, NPP2 and NPP6, respectively, and their enzymatic properties were characterized. NPP1 and NPP6 exhibited hydrolytic activities toward ATP, UDP-glucose and the starch precursor molecule, ADP-glucose, whereas NPP2 did not recognize nucleotide sugars as substrates, but hydrolyzed UDP, ADP and adenosine 5'-phosphosulfate. To gain insight into the physiological function of rice NPP1, an npp1 knockout mutant was characterized. The ADP-glucose hydrolytic activities in shoots of npp1 rice seedlings were 8% of those of the wild type (WT), thus indicating that NPP1 is a major determinant of ADP-glucose hydrolytic activity in rice shoots. Importantly, when seedlings were cultured at 160 Pa CO2 under a 28°C/23°C (12 h light/12 h dark) regime, npp1 shoots and roots were larger than those of wild-type (WT) seedlings. Furthermore, the starch content in the npp1 shoots was higher than that of WT shoots. Growth and starch accumulation were also enhanced under an atmospheric CO2 concentration (40 Pa) when plants were cultured under a 33°C/28°C regime. The overall data strongly indicate that NPP1 exerts a negative effect on plant growth and starch accumulation in shoots, especially under high CO2 concentration and high temperature conditions.

  15. Two-step hydrothermal synthesis of NiCo2S4/Co9S8 nanorods on nickel foam for high energy density asymmetric supercapacitors

    Science.gov (United States)

    Xu, Rui; Lin, Jianming; Wu, Jihuai; Huang, Miaoliang; Fan, Leqing; Chen, Hongwei; He, Xin; Wang, Yiting; Xu, Zedong

    2018-03-01

    It is still a huge challenge to obtain a high-energy-density asymmetric supercapacitors and develop an active electrode material with excellent electrochemical characteristics. Although NiCo2S4 has been considered as one of the promising positive electrode materials for asymmetric supercapacitors, the electrochemical performance of the NiCo2S4-based positive electrodes is still relatively low and cannot meet the demand in the devices. Herein, NiCo2S4/Co9S8 nanorods with a large capacitance are synthesized via a simple two-step hydrothermal treatment. A high-performance asymmetric supercapacitor operating at 1.6 V is successfully assembled using the NiCo2S4/Co9S8 nanorods as positive electrode and activated carbon as negative electrode in 3 M KOH aqueous electrolyte, which demonstrates a fairly high energy density of 49.6 Wh kg-1 at a power density of 123 W kg-1, an excellent capacitance of 0.91 F cm-2 (139.42 F g-1) at current density of 1 mA cm-2 as well as a remarkable cycling stability due to the high physical strength, the large specific surface area, and the good conductivity for NiCo2S4/Co9S8 nanorods and the brilliant synergistic effect for NiCo2S4 and Co9S8 electrode materials. The as-prepared NiCo2S4/Co9S8 nanorods open up a new platform as positive electrode material for high-energy-density asymmetric supercapacitors in energy-storage.

  16. High resolution pCO2 monitoring reveals ventilation of Bunker Cave (NW Germany) and its impact on speleothem growth

    Science.gov (United States)

    Riechelmann, Sylvia; Breitenbach, Sebastian F. M.; Schröder-Ritzrau, Andrea; Immenhauser, Adrian

    2017-04-01

    Understanding the environmental processes that influence geochemical proxies archived in speleothems depends critically on detailed cave monitoring. Cave air pCO2 is one of the most important factors controlling speleothem growth. The pCO2 concentration of cave air depends on (i) the productivity of its source(s), (ii) CO2-transport dynamics through the epikarst and (iii) cave ventilation processes. We monitored the pCO2 concentration ca. 100 m from the lower entrance of the Bunker-Emst-Cave system (NW Germany) with a CORA CO2-logger at a two-hourly resolution between April 2012 and February 2014. Near-atmospheric minimum pCO2 concentrations of 408 ppm are observed in winter, while higher values up to 811 ppm are recorded in summer. Higher summer concentrations are due to increased plant and soil microbial activity, resulting in elevated CO2 in the soil, which is transferred to the cave with infiltrating water. Generally, the front passages of Bunker Cave are well ventilated. Besides the seasonal pattern, pCO2 concentrations vary at diurnal scale. Correlations of pCO2 with the temperature difference between surface and cave air are positive during summer and negative in winter, with no clear pattern for spring and autumn months. Thus, Bunker Cave ventilation is driven by temperature and density differences between cave and surface air, with two entrances at different elevations allowing dynamic ventilation. During summer, relatively cooler cave air flows from the upper to the lower entrance, while in winter this pattern is reversed due to ascending warm cave air. The situation is further complicated by preferential south/southwestern winds that point directly on the cave entrances. Thus, cave ventilation is frequently disturbed, especially during periods of higher wind speed. Modern ventilation systematics only developed when the two cave entrances were artificially opened (1863 and 1926). Before that, ventilation was restricted and cave pCO2 concentrations were

  17. Highly stable ceria-zirconia-yttria supported Ni catalysts for syngas production by CO2 reforming of methane

    Science.gov (United States)

    Muñoz, M. A.; Calvino, J. J.; Rodríguez-Izquierdo, J. M.; Blanco, G.; Arias, D. C.; Pérez-Omil, J. A.; Hernández-Garrido, J. C.; González-Leal, J. M.; Cauqui, M. A.; Yeste, M. P.

    2017-12-01

    Ni/CeO2/YSZ and Ni/Ce0.15Zr0.85O2 have been investigated as catalysts for the dry reforming of methane at 750 °C. Ni was incorporated by the impregnation method. The supports were previously activated by using a thermo-chemical protocol consisting on a severe reduction (H2/Ar) at 950 °C followed by a mild oxidation (O2/He) at 500 °C. According to TPR results, this protocol leads to the development of unique redox properties in the case of the CeO2/YSZ oxide. Two types of CO2 + CH4 (1:1) mixtures (helium-diluted and undiluted) were used to feed the reactor. When using the Ni/Ce0.15Zr0.85O2 catalyst with undiluted feed, the reactor became plugged by coke. By contrast, Ni/CeO2/YSZ behaved as an active and stable catalyst even under the most severe operation conditions. The characterization of the spent Ni/CeO2/YSZ using TGA, TEM, Raman and XPS spectroscopy revealed that only a limited amount of graphitic carbon, in form of nanotubes, was formed. No evidences of deactivating carbonaceous forms were obtained. The singular redox properties of the activated CeO2/YSZ oxides are proposed as a key for designing Ni catalysts highly stable in reforming processes.

  18. The effect of wiping on skin resurfacing in a pig model using a high energy pulsed CO2 laser system.

    Science.gov (United States)

    Ross, E V; Mowlavi, A; Barnette, D; Glatter, R D; Grevelink, J M

    1999-02-01

    The impact of wiping in laser skin resurfacing has not been systematically studied. We examined the effects of wiping during single- and multiple-pass high energy pulsed CO2 laser skin resurfacing in a farm pig. Consequences of wiping were evaluated with regard to depth of residual thermal damage, tissue necrosis, and fibroplasia. Also, the impact of wiping on gross wound healing was observed. Wounds were followed for 21 days and biopsies were obtained on postoperative days 0, 1, and 21. Immediate postoperative biopsies of single-pass wounds showed equivalent residual thermal damage regardless of wiping; in contrast, biopsies from multiple-pass sites without wiping showed more extensive and variable residual thermal damage than wiped sites. On postoperative day one, single pass sites without wiping were grossly less erythematous than wiped sites, and biopsies showed less extensive necrosis and inflammation. In contrast, multiple pass sites without wiping were grossly more erythematous than corresponding wiped sites, and biopsies revealed significantly increased and variable necrosis. After 21 days, multiple pass sites without wiping were grossly more erythematous and showed a thicker band of fibroplasia microscopy. For single pass wounds, not wiping decreased the level of wounding. In contrast, not wiping in multiple pass wounds significantly increased the depth and variability of residual thermal damage and necrosis, resulting in prolonged healing.

  19. 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.

  20. Hydrogenation of organic matter as a terminal electron sink sustains high CO 2 :CH 4 production ratios during anaerobic decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Rachel M.; Tfaily, Malak M.; Rich, Virginia I.; Keller, Jason K.; Bridgham, Scott D.; Zalman, Cassandra Medvedeff; Meredith, Laura; Hanson, Paul J.; Hines, Mark; Pfeifer-Meister, Laurel; Saleska, Scott R.; Crill, Patrick; Cooper, William T.; Chanton, Jeff P.; Kostka, Joel E.

    2017-10-01

    Once inorganic electron acceptors are depleted, organic matter in anoxic environments decomposes by hydrolysis, fermentation, and methanogenesis, requiring syntrophic interactions between microorganisms to achieve energetic favorability. In this classic anaerobic food chain, methanogenesis represents the terminal electron accepting (TEA) process, ultimately producing equimolar CO2 and CH4 for each molecule of organic matter degraded. However, CO2:CH4 production in Sphagnum-derived, mineral-poor, cellulosic peat often substantially exceeds this 1:1 ratio, even in the absence of measureable inorganic TEAs. Since the oxidation state of C in both cellulose-derived organic matter and acetate is 0, and CO2 has an oxidation state of +4, if CH4 (oxidation state -4) is not produced in equal ratio, then some other compound(s) must balance CO2 production by receiving 4 electrons. Here we present evidence for ubiquitous hydrogenation of diverse unsaturated compounds that appear to serve as organic TEAs in peat, thereby providing the necessary electron balance to sustain CO2:CH4 >1. While organic electron acceptors have previously been proposed to drive microbial respiration of organic matter through the reversible reduction of quinone moieties, the hydrogenation mechanism that we propose, by contrast, reduces C-C double bonds in organic matter thereby serving as 1) a terminal electron sink, 2) a mechanism for degrading complex unsaturated organic molecules, 3) a potential mechanism to regenerate electron-accepting quinones, and, in some cases, 4) a means to alleviate the toxicity of unsaturated aromatic acids. This mechanism for CO2 generation without concomitant CH4 production has the potential to regulate the global warming potential of peatlands by elevating CO2:CH4 production ratios.

  1. Three-Dimensional NiCo2O4@Polypyrrole Coaxial Nanowire Arrays on Carbon Textiles for High-Performance Flexible Asymmetric Solid-State Supercapacitor.

    Science.gov (United States)

    Kong, Dezhi; Ren, Weina; Cheng, Chuanwei; Wang, Ye; Huang, Zhixiang; Yang, Hui Ying

    2015-09-30

    In this article, we report a novel electrode of NiCo2O4 nanowire arrays (NWAs) on carbon textiles with a polypyrrole (PPy) nanosphere shell layer to enhance the pseudocapacitive performance. The merits of highly conductive PPy and short ion transport channels in ordered NiCo2O4 mesoporous nanowire arrays together with the synergistic effect between NiCo2O4 and PPy result in a high specific capacitance of 2244 F g(-1), excellent rate capability, and cycling stability in NiCo2O4/PPy electrode. Moreover, a lightweight and flexible asymmetric supercapacitor (ASC) device is successfully assembled using the hybrid NiCo2O4@PPy NWAs and activated carbon (AC) as electrodes, achieving high energy density (58.8 W h kg(-1) at 365 W kg(-1)), outstanding power density (10.2 kW kg(-1) at 28.4 W h kg(-1)) and excellent cycling stability (∼89.2% retention after 5000 cycles), as well as high flexibility. The three-dimensional coaxial architecture design opens up new opportunities to fabricate a high-performance flexible supercapacitor for future portable and wearable electronic devices.

  2. The hybrid nanostructure of MnCo2O4.5 nanoneedle/carbon aerogel for symmetric supercapacitors with high energy density.

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Li, Liyi; Tuan, Chia-Chi; Li, Haidong; Sang, Yuanhua; Jiang, Huaidong; Wong, C P; Liu, Hong

    2015-09-14

    Current applications of carbon-based supercapacitors are limited by their low energy density. One promising strategy to enhance the energy density is to couple metal oxides with carbon materials. In this study, a porous MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure was synthesized by assembling MnCo2O4.5 nanoneedle arrays on the surface of channel walls of hierarchical porous carbon aerogels derived from chitosan for the supercapacitor application. The synthetic process of the hybrid nanostructure involves two steps, i.e. the growth of Mn-Co precursors on carbon aerogel by a hydrothermal process and the conversion of the precursor into MnCo2O4.5 nanoneedles by calcination. The carbon aerogel exhibits a high electrical conductivity, high specific surface area and porous structure, ensuring high electrochemical performance of the hybrid nanostructure when coupled with the porous MnCo2O4.5 nanoneedles. The symmetric supercapacitor using the MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure as the active electrode material exhibits a high energy density of about 84.3 Wh kg(-1) at a power density of 600 W kg(-1). The voltage window is as high as 1.5 V in neutral aqueous electrolytes. Due to the unique nanostructure of the electrodes, the capacitance retention reaches 86% over 5000 cycles.

  3. 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

  4. 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.

  5. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: the effect of donor fluorination on strong collision energy transfer.

    Science.gov (United States)

    Kim, Kilyoung; Johnson, Alan M; Powell, Amber L; Mitchell, Deborah G; Sevy, Eric T

    2014-12-21

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm(-1)) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ∼41,000 cm(-1) was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1→S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ΔE region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ΔE region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.

  6. Multi-Channel Auto-Dilution System for Remote Continuous Monitoring of High Soil-CO2 Fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Amonette, James E.; Barr, Jonathan L.

    2009-04-23

    Geological sequestration has the potential capacity and longevity to significantly decrease the amount of anthropogenic CO2 introduced into the atmosphere by combustion of fossil fuels such as coal. Effective sequestration, however, requires the ability to verify the integrity of the reservoir and ensure that potential leakage rates are kept to a minimum. Moreover, understanding the pathways by which CO2 migrates to the surface is critical to assessing the risks and developing remediation approaches. Field experiments, such as those conducted at the Zero Emissions Research and Technology (ZERT) project test site in Bozeman, Montana, require a flexible CO2 monitoring system that can accurately and continuously measure soil-surface CO2 fluxes for multiple sampling points at concentrations ranging from background levels to several tens of percent. To meet this need, PNNL is developing a multi-port battery-operated system capable of both spatial and temporal monitoring of CO2 at concentrations from ambient to at least 150,000 ppmv. This report describes the system components (sampling chambers, measurement and control system, and power supply) and the results of a field test at the ZERT site during the late summer and fall of 2008. While the system performed well overall during the field test, several improvements to the system are suggested for implementation in FY2009.

  7. Selection of microalgae for high CO2 fixation efficiency and lipid accumulation from ten Chlorella strains using municipal wastewater.

    Science.gov (United States)

    Hu, Xia; Zhou, Jiti; Liu, Guangfei; Gui, Bing

    2016-08-01

    As significant differences in cellular physiology, metabolic potential and genetics occur among strains with morphological similarity, the screening of appropriate microalgae species for effective CO2 fixation and biodiesel production is extremely critical. In this study, ten strains of Chlorella were cultivated in municipal wastewater influent (MWI) and their tolerance for MWI, CO2 fixation efficiency and lipid productivity were assessed. The results showed that the biomass concentrations of four strains (Chlorella vulgaris, Chlorella 64.01, Chlorella regularis var. minima and Chlorella sp.) were significantly higher than other strains. When the cultivation systems were aerated with 10% CO2, Chlorella sp. showed the highest CO2 fixation efficiency (35.51%), while the highest lipid accumulation (58.48%) was observed with C. vulgaris. Scanning electron microscopy images revealed that the cells of both Chlorella sp. and C. vulgaris kept their normal morphologies after 15day batch culture. These findings indicated that Chlorella sp. and C. vulgaris have fairly good tolerance for MWI, and moreover, Chlorella sp. was appropriate for CO2 fixation while C. vulgaris represented the highest potential for producing biodiesel. Copyright © 2016. Published by Elsevier B.V.

  8. Hydrothermal synthesis of Mn-doped ZnCo2O4 electrode material for high-performance supercapacitor

    Science.gov (United States)

    Mary, A. Juliet Christina; Bose, A. Chandra

    2017-12-01

    Mn-doped ZnCo2O4 nanoparticle has been synthesized by hydrothermal method without adding any surfactants. Structural, morphological and electrochemical performances have been studied for the pure and various concentration of Mn-doped ZnCo2O4 nanoparticles. XRD and Raman studies demonstrate the crystalline structure of the material. Specific capacitance of the 10 wt% Mn doped ZnCo2O4 nanomaterial is analysed using the three-electrode system. 10 wt% Mn-doped ZnCo2O4 has a maximum capacitance of 707.4 F g-1 at a current density of 0.5 A g-1. Coulombic efficiency of the material is 96.3% for 500 cycles in the KOH electrolyte medium. A two-electrode device using 10 wt% Mn-doped ZnCo2O4 exhibits the highest specific capacitance of 6.5 F g-1 at a current density of 0.03 A g-1 which is the suitable material for supercapacitor application.

  9. Electrocatalytic CO2 Reduction with a Homogeneous Catalyst in Ionic Liquid: High Catalytic Activity at Low Overpotential.

    Science.gov (United States)

    Grills, David C; Matsubara, Yasuo; Kuwahara, Yutaka; Golisz, Suzanne R; Kurtz, Daniel A; Mello, Barbara A

    2014-06-05

    We describe a new strategy for enhancing the efficiency of electrocatalytic CO2 reduction with a homogeneous catalyst, using a room-temperature ionic liquid as both the solvent and electrolyte. The electrochemical behavior of fac-ReCl(2,2'-bipyridine)(CO)3 in neat 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][TCB]) was compared with that in acetonitrile containing 0.1 M [Bu4N][PF6]. Two separate one-electron reductions occur in acetonitrile (-1.74 and -2.11 V vs Fc(+/0)), with a modest catalytic current appearing at the second reduction wave under CO2. However, in [emim][TCB], a two-electron reduction wave appears at -1.66 V, resulting in a ∼0.45 V lower overpotential for catalytic reduction of CO2 to CO. Furthermore, the apparent CO2 reduction rate constant, kapp, in [emim][TCB] exceeds that in acetonitrile by over one order of magnitude (kapp = 4000 vs 100 M(-1) s(-1)) at 25 ± 3 °C. Supported by time-resolved infrared measurements, a mechanism is proposed in which an interaction between [emim](+) and the two-electron reduced catalyst results in rapid dissociation of chloride and a decrease in the activation energy for CO2 reduction.

  10. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Science.gov (United States)

    Bermúdez, José M.; Dominguez, Pablo Haro; Arenillas, Ana; Cot, Jaume; Weber, Jens; Luque, Rafael

    2013-01-01

    Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar) and capacities (>2 mmol·g−1 at 273 K). Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes. PMID:28788352

  11. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Directory of Open Access Journals (Sweden)

    Ana Arenillas

    2013-10-01

    Full Text Available Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar and capacities (>2 mmol·g−1 at 273 K. Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes.

  12. High Resilience in Heathland Plants to Changes in Temperature, Drought, and CO2 in Combination: Results from the CLIMAITE Experiment

    DEFF Research Database (Denmark)

    Kongstad, J.; Schmidt, Inger K.; Riis-Nielsen, Torben

    2012-01-01

    the standingbiomass for either D. flexuosa or the ecosystem asmore litter was produced. Treatment combinationsshowed little interactions on the measuredparameters and in particular elevated CO2 did notcounterbalance the drought effect on plant growth,as we had anticipated. The plant community didnot show any......Climate change scenarios predict simultaneouslyincrease in temperature, altered precipitation patternsand elevated atmospheric CO2 concentration,which will affect key ecosystem processes and plantgrowth and species interactions. In a large-scaleexperiment, we investigated the effects...... of in situexposure to elevated atmospheric CO2 concentration,increased temperature and prolonged droughtperiods on the plant biomass in a dry heathland(Brandbjerg, Denmark). Results after 3 yearsshowed that drought reduced the growth of thetwo dominant species Deschampsia flexuosa and Callunavulgaris. However, both...

  13. High-altitude CO2 Clouds On Mars: A View From MEx Observations, The LMD MGCM, And Convective Potential Calculations

    Science.gov (United States)

    Maattanen, Anni; Montmessin, F.; Gondet, B.; Hoffmann, H.; Scholten, F.; Gonzalez-Galindo, F.; Spiga, A.; Forget, F.; Hauber, E.; Bertaux, J.; Bibring, J.; Neukum, G.

    2010-10-01

    We will summarize 3.5 Martian years (Mars Years 27-30) of high-altitude CO2 cloud data from MEx/OMEGA and selected results from Mex/HRSC. The 3-year dataset shows that the equatorial cloud activity is centered around the northern summer solstice with a pause at the aphelion, and that their appearance is limited in latitude and longitude. HRSC-measured altitudes and cloud speeds provide a rare dataset for comparison with GCMs. A comparison with the LMD Mars Global Climate Model shows a good agreement between the model-predicted winds and those observed by the HRSC. The LMD-MGCM predicts a strong diurnal variation of temperature at the cloud observation altitudes due to the propagation of the diurnal thermal tide. The coldest temperatures in the near-equator cloud altitude range (60-85 km) are observed towards the end of the afternoon, whereas the warmest temperatures are found in the early morning hours. Most of the observed clouds are cirrus-type, filamented clouds, but some OMEGA-observed clouds exhibit round, clumpy structures that have been suggested to be of convective origin. We asses the plausibility of the hypothesis of mesospheric convection in light of observations and theoretical Convective Available Potential Energy calculations. Estimates of convective potential and vertical velocities based on observed cloud properties suggest that the convective clouds could most likely be clusters of smaller scale convective updrafts. SPICAM stellar occultations have revealed large supersaturations at high altitudes: to attain the estimated values of CAPE and vertical velocity, most probably only moderate deviations from saturation are required. Based on nucleation modeling, such deviations may imply cloud formation via heterogeneous nucleation onto small condensation nuclei.

  14. High-Pressure Measurements of Temperature and CO2 Concentration Using Tunable Diode Lasers at 2 μm.

    Science.gov (United States)

    Cai, Tingdong; Gao, Guangzhen; Wang, Minrui; Wang, Guishi; Liu, Ying; Gao, Xiaoming

    2016-03-01

    A sensor for simultaneous measurements of temperature and carbon dioxide (CO2) concentration at elevated pressure is developed using tunable diode lasers at 2 µm. Based on some selection rules, a CO2 line pair at 5006.140 and 5010.725 cm(-1) is selected for the TDL sensor. In order to ensure the accuracy and rapidity of the sensor, a quasi-fixed-wavelength WMS is employed. Normalization of the 2f signal with the 1f signal magnitude is used to remove the need for calibration and correct for transmission variation due to beam steering, mechanical misalignments, soot, and windows fouling. Temperatures are obtained from comparison of the background-subtracted 1f-normalized WMS-2f signals ratio and a 1f-normalized WMS-2f peak values ratio model. CO2 concentration is inferred from the 1f-normalized WMS-2f peak values of the CO2 transition at 5006.140 cm(-1). Measurements of temperature and CO2 concentration are carried out in static cell experiments (P = 1-10 atm, T = 500-1200 K) to validate the accuracy and ability of the sensor. The results show that accuracy of the sensor for temperature and CO2 concentration are 1.66% temperature and 3.1%, respectively. All the measurements show the potential utility of the sensor for combustion diagnose at elevated pressure. © The Author(s) 2016.

  15. The fate of pelagic CaCO3 production in a high CO2 ocean: a model study

    OpenAIRE

    Gehlen, M; R. Gangstø; Schneider, B.; L. Bopp; O. Aumont; Ethe, C.

    2007-01-01

    This model study addresses the change in pelagic calcium carbonate production (CaCO3, as calcite in the model) and dissolution in response to rising atmospheric CO2. The parameterization of CaCO3 production includes a dependency on the saturation state of seawater with respect to calcite. It was derived from laboratory and mesocosm studies on particulate organic and inorganic carbon production in Emiliania huxleyi as a function of pCO2. The model predicts values of CaCO3 pro...

  16. Vertical profiling of CH4 and CO2 based on high resolution ground-based NIR heterodyne spectro-radiometry

    Science.gov (United States)

    Klimchuk, Artem; Rodin, Alexander V.; Nadezhdinskii, Alexander; Spiridonov, Maxim; Churbanov, Dmitriy

    A compact, lightweight heterodyne NIR spectro-radiometer suitable for ground-based atmospheric sounding by direct spectro-radimetry of Sun spectrum with spectral resolution lambda / deltalambda=5*10 (7) has been used for precise measurements and vertical profiling of methane and carbon dioxide. Highly stabilized DFB laser was used as local oscillator, while single model quartz fiber Y-coupler served as a diplexer. Radiation mixed in the single mode fiber was detected by quadratic detector using p-i-n diode within the bandpass of 10 MHz. Wavelength coverage of spectral measurement was provided by sweeping local oscillator frequency in the range 1,1 cm (-1) . With the exposure time of 15 min, the absorption spectrum of the atmosphere over Moscow has been recorded with S/N=300. We retrieved methane vertical profile using Tikhonov method of smooth functional, which takes into account a priori information about first guess profile. The reference to model methane profile means that the regularization procedure always selects a priori values unless the measurements contradict this assumption. The retrieved methane profile demonstrates higher abundances in the lower scale height compared to the assumed model profile, well expected in the megalopolis center. The retrievals sensitivity is limited by 10 ppb, with the exception of the lower part of the profile where the tendency to lower values is revealed. Thus the methane abundance variations may be evaluated with relative accuracy better than 1%, which fits the requirements of greenhouse gas monitoring. The CO2 profile has also been retrieved with the accuracy sufficient for analyzing regional sources of greenhouse gases.

  17. Chemical synthesis of hierarchical NiCo2S4 nanosheets like nanostructure on flexible foil for a high performance supercapacitor.

    Science.gov (United States)

    Kim, D -Y; Ghodake, G S; Maile, N C; Kadam, A A; Sung Lee, Dae; Fulari, V J; Shinde, S K

    2017-08-29

    In this study, hierarchical interconnected nickel cobalt sulfide (NiCo2S4) nanosheets were effectively deposited on a flexible stainless steel foil by the chemical bath deposition method (CBD) for high-performance supercapacitor applications. The resulting NiCo2S4 sample was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical measurements. XRD and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of the ternary NiCo2S4 sample with a pure cubic phase. FE-SEM and HR-TEM revealed that the entire foil surface was fully covered with the interconnected nanosheets like surface morphology. The NiCo2S4 nanosheets demonstrated impressive electrochemical characteristics with a specific capacitance of 1155 F g-1 at 10 mV s-1 and superior cycling stability (95% capacity after 2000 cycles). These electrochemical characteristics could be attributed to the higher active area and higher conductivity of the sample. The results demonstrated that the interconnected NiCo2S4 nanosheets are promising as electrodes for supercapacitor and energy storage applications.

  18. The metabolic response of thecosome pteropods from the North Atlantic and North Pacific oceans to high CO2 and low O2

    Science.gov (United States)

    Maas, Amy E.; Lawson, Gareth L.; Aleck Wang, Zhaohui

    2016-11-01

    As anthropogenic activities directly and indirectly increase carbon dioxide (CO2) and decrease oxygen (O2) concentrations in the ocean system, it becomes important to understand how different populations of marine animals will respond. Water that is naturally low in pH, with a high concentration of carbon dioxide (hypercapnia) and a low concentration of oxygen, occurs at shallow depths (200-500 m) in the North Pacific Ocean, whereas similar conditions are absent throughout the upper water column in the North Atlantic. This contrasting hydrography provides a natural experiment to explore whether differences in environment cause populations of cosmopolitan pelagic calcifiers, specifically the aragonitic-shelled pteropods, to have a different physiological response when exposed to hypercapnia and low O2. Using closed-chamber end-point respiration experiments, eight species of pteropods from the two ocean basins were exposed to high CO2 ( ˜ 800 µatm) while six species were also exposed to moderately low O2 (48 % saturated, or ˜ 130 µmol kg-1) and a combined treatment of low O2/high CO2. None of the species tested showed a change in metabolic rate in response to high CO2 alone. Of those species tested for an effect of O2, only Limacina retroversa from the Atlantic showed a response to the combined treatment, resulting in a reduction in metabolic rate. Our results suggest that pteropods have mechanisms for coping with short-term CO2 exposure and that there can be interactive effects between stressors on the physiology of these open ocean organisms that correlate with natural exposure to low O2 and high CO2. These are considerations that should be taken into account in projections of organismal sensitivity to future ocean conditions.

  19. The metabolic response of thecosome pteropods from the North Atlantic and North Pacific oceans to high CO2 and low O2

    Directory of Open Access Journals (Sweden)

    A. E. Maas

    2016-11-01

    Full Text Available As anthropogenic activities directly and indirectly increase carbon dioxide (CO2 and decrease oxygen (O2 concentrations in the ocean system, it becomes important to understand how different populations of marine animals will respond. Water that is naturally low in pH, with a high concentration of carbon dioxide (hypercapnia and a low concentration of oxygen, occurs at shallow depths (200–500 m in the North Pacific Ocean, whereas similar conditions are absent throughout the upper water column in the North Atlantic. This contrasting hydrography provides a natural experiment to explore whether differences in environment cause populations of cosmopolitan pelagic calcifiers, specifically the aragonitic-shelled pteropods, to have a different physiological response when exposed to hypercapnia and low O2. Using closed-chamber end-point respiration experiments, eight species of pteropods from the two ocean basins were exposed to high CO2 ( ∼  800 µatm while six species were also exposed to moderately low O2 (48 % saturated, or  ∼  130 µmol kg−1 and a combined treatment of low O2/high CO2. None of the species tested showed a change in metabolic rate in response to high CO2 alone. Of those species tested for an effect of O2, only Limacina retroversa from the Atlantic showed a response to the combined treatment, resulting in a reduction in metabolic rate. Our results suggest that pteropods have mechanisms for coping with short-term CO2 exposure and that there can be interactive effects between stressors on the physiology of these open ocean organisms that correlate with natural exposure to low O2 and high CO2. These are considerations that should be taken into account in projections of organismal sensitivity to future ocean conditions.

  20. Lime-Based Sorbents for High-Temperature CO2 Capture—A Review of Sorbent Modification Methods

    Directory of Open Access Journals (Sweden)

    Edward J. Anthony

    2010-08-01

    Full Text Available This paper presents a review of the research on CO2 capture by lime-based looping cycles undertaken at CanmetENERGY’s (Ottawa, Canada research laboratories. This is a new and very promising technology that may help in mitigation of global warming and climate change caused primarily by the use of fossil fuels. The intensity of the anticipated changes urgently requires solutions such as more cost-effective technologies for CO2 capture. This new technology is based on the use of lime-based sorbents in a dual fluidized bed combustion (FBC reactor which contains a carbonator—a unit for CO2 capture, and a calciner—a unit for CaO regeneration. However, even though natural materials are cheap and abundant and very good candidates as solid CO2 carriers, their performance in a practical system still shows significant limitations. These limitations include rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation from FBC reactors. Therefore, research on sorbent performance is critical and this paper reviews some of the promising ways to overcome these shortcomings. It is shown that reactivation by steam/water, thermal pre-treatment, and doping simultaneously with sorbent reforming and pelletization are promising potential solutions to reduce the loss of activity of these sorbents over multiple cycles of use.

  1. 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.

  2. Development of tunable high pressure CO2 laser for lidar measurements of pollutants and wind velocities, January 1976 to December 1977

    Science.gov (United States)

    Javan, A.

    1979-01-01

    A tunable multiatmospheric pulsed CO2 laser with emphasis on experimental features and supporting theoretical analyses important to differential absorption lidar and Doppler lidar measurement of pollutants and wind velocities is reported. The energy deposition and the means to produce the uniform high density plasma in the multiatmospheric medium, through UV preionization of an organic seed gas is discussed. Design features of the pulsed CO2 laser are presented. The radiative processes which are operative and prevent the laser from breaking into oscillations in a large number of modes over its broad amplification bandwidth are described. The mode competition for the transient pulsed laser oscillation in a standing wave and traveling wave ring laser configuration is discussed and contrasted with the approach to steady state oscillations. The latter findings are important to transient injection locking for production of a highly stable pulsed CO2 laser output.

  3. Global distributions of CO2 volume mixing ratio in the middle and upper atmosphere from daytime MIPAS high-resolution spectra

    Science.gov (United States)

    Aythami Jurado-Navarro, Á.; López-Puertas, Manuel; Funke, Bernd; García-Comas, Maya; Gardini, Angela; González-Galindo, Francisco; Stiller, Gabriele P.; von Clarmann, Thomas; Grabowski, Udo; Linden, Andrea

    2016-12-01

    Global distributions of the CO2 vmr (volume mixing ratio) in the mesosphere and lower thermosphere (from 70 up to ˜ 140 km) have been derived from high-resolution limb emission daytime MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) spectra in the 4.3 µm region. This is the first time that the CO2 vmr has been retrieved in the 120-140 km range. The data set spans from January 2005 to March 2012. The retrieval of CO2 has been performed jointly with the elevation pointing of the line of sight (LOS) by using a non-local thermodynamic equilibrium (non-LTE) retrieval scheme. The non-LTE model incorporates the new vibrational-vibrational and vibrational-translational collisional rates recently derived from the MIPAS spectra by [Jurado-Navarro et al.(2015)]. It also takes advantage of simultaneous MIPAS measurements of other atmospheric parameters (retrieved in previous steps), such as the kinetic temperature (derived up to ˜ 100 km from the CO2 15 µm region of MIPAS spectra and from 100 up to 170 km from the NO 5.3 µm emission of the same MIPAS spectra) and the O3 measurements (up to ˜ 100 km). The latter is very important for calculations of the non-LTE populations because it strongly constrains the O(3P) and O(1D) concentrations below ˜ 100 km. The estimated precision of the retrieved CO2 vmr profiles varies with altitude ranging from ˜ 1 % below 90 km to 5 % around 120 km and larger than 10 % above 130 km. There are some latitudinal and seasonal variations of the precision, which are mainly driven by the solar illumination conditions. The retrieved CO2 profiles have a vertical resolution of about 5-7 km below 120 km and between 10 and 20 km at 120-140 km. We have shown that the inclusion of the LOS as joint fit parameter improves the retrieval of CO2, allowing for a clear discrimination between the information on CO2 concentration and the LOS and also leading to significantly smaller systematic errors. The retrieved CO2 has an improved

  4. Viability of sublethally injured coliform bacteria on fresh-cut cabbage stored in high CO2atmospheres following rinsing with electrolyzed water.

    Science.gov (United States)

    Izumi, Hidemi; Inoue, Ayano

    2018-02-02

    The extent of sublethally injured coliform bacteria on shredded cabbage, either rinsed or not rinsed with electrolyzed water, was evaluated during storage in air and high CO 2 controlled atmospheres (5%, 10%, and 15%) at 5°C and 10°C using the thin agar layer (TAL) method. Sublethally injured coliform bacteria on nonrinsed shredded cabbage were either absent or they were injured at a 64-65% level when present. Rinsing of shredded cabbage with electrolyzed water containing 25ppm available chlorine reduced the coliform counts by 0.4 to 1.1 log and caused sublethal injury ranging from 42 to 77%. Pantoea ananatis was one of the species injured by chlorine stress. When shredded cabbage, nonrinsed or rinsed with electrolyzed water, was stored in air and high CO 2 atmospheres at 5°C for 7days and 10°C for 5days, coliform counts on TAL plates increased from 3.3-4.5 to 6.5-9.0 log CFU/g during storage, with the increase being greater at 10°C than at 5°C. High CO 2 of 10% and 15% reduced the bacterial growth on shredded cabbage during storage at 5°C. Although injured coliform bacteria were not found on nonrinsed shredded cabbage on the initial day, injured coliforms at a range of 49-84% were detected on samples stored in air and high CO 2 atmospheres at 5°C and 10°C. Injured cells were detected more frequently during storage at both temperatures irrespective of the CO 2 atmosphere when shredded cabbage was rinsed with electrolyzed water. These results indicated that injured coliform bacteria on shredded cabbage, either rinsed or not rinsed with electrolyzed water, exhibited different degrees of injury during storage regardless of the CO 2 atmosphere and temperature tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Daily Changes in CO2 and Water Vapor Exchange, Chlorophyll Fluorescence, and Leaf Water Relations in the Halophyte Mesembryanthemum crystallinum during the Induction of Crassulacean Acid Metabolism in Response to High NaCl Salinity 1

    Science.gov (United States)

    Winter, Klaus; Gademann, Rolf

    1991-01-01

    Simultaneous measurements of net CO2 exchange, water vapor exchange, and leaf water relations were performed in Mesembryanthemum crystallinum during the development of crassulacean acid metabolism (CAM) in response to high NaCl salinity in the rooting medium. Determinations of chlorophyll a fluorescence were used to estimate relative changes in electron transport rate. Alterations in leaf mass per unit area, which—on a short-term basis—largely reflect changes in water content, were recorded continuously with a beta-gauge. Turgor pressure of mesophyll cells was determined with a pressure probe. As reported previously (K Winter, DJ von Willert [1972] Z Pflanzenphysiol 67: 166-170), recently expanded leaves of plants grown under nonsaline conditions showed gas-exchange characteristics of a C3 plant. Although these plants were not exposed to any particular stress treatment, water content and turgor pressure regularly decreased toward the end of the 12 hour light periods and recovered during the following 12 hours of darkness. When the NaCl concentration of the rooting medium was raised to 400 millimolar, in increments of 100 millimolar given at the onset of the photoperiods for 4 consecutive days, leaf water content and turgor pressure decreased by as much as 30 and 60%, respectively, during the course of the photoperiods. These transient decreases probably triggered the induction of the biochemical machinery which is required for CAM to operate. After several days at 400 millimolar NaCl, when leaves showed features typical of CAM, overall turgor pressure and leaf mass per unit area had increased above the levels before onset of the salt treatment, and diurnal alterations in leaf water content were reduced. Net carbon gain during photoperiods and average intercellular CO2 partial pressures at which net CO2 uptake occurred, progressively decreased upon salinization. Reversible diurnal depressions in leaf conductance and net CO2 uptake, with minima recorded in the

  6. CO2NNIE

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2015-01-01

    We propose a system for calculating the personalized annual fuel consumption and CO2 emissions from transportation. The system, named CO2NNIE, estimates the fuel consumption on the fastest route between the frequent destinations of the user. The travel time and fuel consumption estimated are based......% of the actual fuel consumption (4.6% deviation on average). We conclude, that the system provides new detailed information on CO2 emissions and fuel consumption for any make and model....

  7. Self-assembled NiCo2O4-anchored reduced graphene oxide nanoplates as high performance anode materials for lithium ion batteries

    Science.gov (United States)

    Yang, Juan; Tian, Hangyu; Tang, Jingjing; Bai, Tao; Xi, Lihua; Chen, Sanmei; Zhou, Xiangyang

    2017-12-01

    The NiCo2O4-anchored reduced graphene oxide (NiCo2O4@rGO) nanoplates have been synthesized by a facile self-assembly process. The morphology, crystalline structure and electrochemical performance of the materials have been investigated comprehensively. The results of SEM manifest that NiCo2O4 particles have been densely anchored on the surface of rGO with a mesoporous structure, and the morphology is tunable via altering concentration of urea during the preparation process. Due to the high ratio of NiCo2O4 in the composite and the plate structure, the electrochemical performance of as-prepared material has been greatly improved. When evaluated as anode materials in lithium ion batteries (LIBs), the as-prepared NiCo2O4@rGO nanocomposite delivers a reversible capacity of 994 mAh g-1 at a current density of 200 mA g-1 with outstanding rate capability, revealing that it could be a promising anode for LIBs.

  8. A Moisture Stable 3D Microporous Co(II)-MOF with Potential for Highly Selective CO2 Separation under Ambient Conditions.

    Science.gov (United States)

    Chand, Santanu; Pal, Arun; Das, Madhab C

    2018-02-13

    Selective adsorption and separation of CO2 from flue gas and landfill gas mixtures have drawn great attention in industry. Porous MOF materials are promising alternatives to achieve such separations, however, the stability in presence of moisture must be taken into consideration. Here, we have constructed a microporous MOF {[Co(OBA)(L)0.5]·S}n (IITKGP-8), by employing a V-shaped organic linker with a azo functionalized N,N' spacer forming a 3D network with mab topology and 1D rhombus-shaped channels along crystallographic 'b' axis with void volume of 34.2 %. The activated MOF reveals moderate CO2 uptake capacity of 55.4 and 26.5 cm3g-1 at 273K/1 bar and 295 K/1 bar respectively, whereas it takes up significantly lower amount of CH4 and N2 under similar conditions and thus exhibiting its potential for highly selective sorption of CO2 with excellent IAST selectivity of CO2/N2 (106 at 273K and 43.7 at 295K) and CO2/CH4 (17.7 at 273K and 17.1 at 295K) under 1 bar. More importantly, this MOF exhibits excellent moisture stability as assessed through PXRD experiments coupled with surface area analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. CO2Plasma-Treated TiO2Film as an Effective Electron Transport Layer for High-Performance Planar Perovskite Solar Cells.

    Science.gov (United States)

    Wang, Kang; Zhao, Wenjing; Liu, Jia; Niu, Jinzhi; Liu, Yucheng; Ren, Xiaodong; Feng, Jiangshan; Liu, Zhike; Sun, Jie; Wang, Dapeng; Liu, Shengzhong Frank

    2017-10-04

    Perovskite solar cells (PSCs) have received great attention because of their excellent photovoltaic properties especially for the comparable efficiency to silicon solar cells. The electron transport layer (ETL) is regarded as a crucial medium in transporting electrons and blocking holes for PSCs. In this study, CO 2 plasma generated by plasma-enhanced chemical vapor deposition (PECVD) was introduced to modify the TiO 2 ETL. The results indicated that the CO 2 plasma-treated compact TiO 2 layer exhibited better surface hydrophilicity, higher conductivity, and lower bulk defect state density in comparison with the pristine TiO 2 film. The quality of the stoichiometric TiO 2 structure was improved, and the concentration of oxygen-deficiency-induced defect sites was reduced significantly after CO 2 plasma treatment for 90 s. The PSCs with the TiO 2 film treated by CO 2 plasma for 90 s exhibited simultaneously improved short-circuit current (J SC ) and fill factor. As a result, the PSC-based TiO 2 ETL with CO 2 plasma treatment affords a power conversion efficiency of 15.39%, outperforming that based on pristine TiO 2 (13.54%). These results indicate that the plasma treatment by the PECVD method is an effective approach to modify the ETL for high-performance planar PSCs.

  10. Synergistic effect in the heterostructure of ZnCo2O4 and hydrogenated zinc oxide nanorods for high capacitive response.

    Science.gov (United States)

    Deka Boruah, Buddha; Maji, Arnab; Misra, Abha

    2017-07-13

    Herein, a novel heterostructure was fabricated by combining electrochemically and optically active materials to ach