WorldWideScience

Sample records for temperature co2 separation

  1. 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

  2. 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.

  3. 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.

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

    KAUST Repository

    Li, Peng

    2014-11-13

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

  6. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  7. Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature Range During Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Panagiotis G. Smirniotis

    2007-06-30

    In chapter 1, the studies focused on the development of novel sorbents for reducing the carbon dioxide emissions at high temperatures. Our studies focused on cesium doped CaO sorbents with respect to other major flue gas compounds in a wide temperature range. The thermo-gravimetric analysis of sorbents with loadings of CaO doped on 20 wt% cesium demonstrated high CO{sub 2} sorption uptakes (up to 66 wt% CO{sub 2}/sorbent). It is remarkable to note that zero adsorption affinity for N{sub 2}, O{sub 2}, H{sub 2}O and NO at temperatures as high as 600 C was observed. For water vapor and nitrogen oxide we observed a positive effect for CO{sub 2} adsorption. In the presence of steam, the CO{sub 2} adsorption increased to the highest adsorption capacity of 77 wt% CO{sub 2}/sorbent. In the presence of nitrogen oxide, the final CO{sub 2} uptake remained same, but the rate of adsorption was higher at the initial stages (10%) than the case where no nitrogen oxide was fed. In chapter 2, Ca(NO{sub 3}){sub 2} {center_dot} 4H{sub 2}O, CaO, Ca(OH){sub 2}, CaCO{sub 3}, and Ca(CH{sub 3}COO){sub 2} {center_dot} H{sub 2}O were used as precursors for synthesis of CaO sorbents on this work. The sorbents prepared from calcium acetate (CaAc{sub 2}-CaO) resulted in the best uptake characteristics for CO{sub 2}. It possessed higher BET surface area and higher pore volume than the other sorbents. According to SEM images, this sorbent shows 'fluffy' structure, which probably contributes to its high surface area and pore volume. When temperatures were between 550 and 800 C, this sorbent could be carbonated almost completely. Moreover, the carbonation progressed dominantly at the initial short period. Under numerous adsorption-desorption cycles, the CaAc{sub 2}-CaO demonstrated the best reversibility, even under the existence of 10 vol % water vapor. In a 27 cyclic running, the sorbent sustained fairly high carbonation conversion of 62%. Pore size distributions indicate that their

  8. Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature range during Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Panagiotis Smirniotis

    2002-09-17

    A number basic sorbents based on CaO were synthesized, characterized with novel techniques and tested for sorption of CO{sub 2} and selected gas mixtures simulating flue gas from coal fired boilers. Our studies resulted in highly promising sorbents which demonstrated zero affinity for N{sub 2}, O{sub 2}, SO{sub 2}, and NO very low affinity for water, ultrahigh CO{sub 2} sorption capacities, and rapid sorption characteristics, CO{sub 2} sorption at a very wide temperature range, durability, and low synthesis cost. One of the 'key' characteristics of the proposed materials is the fact that we can control very accurately their basicity (optimum number of basic sites of the appropriate strength) which allows for the selective chemisorption of CO{sub 2} at a wide range of temperatures. These unique characteristics of this family of sorbents offer high promise for development of advanced industrial sorbents for the effective CO{sub 2} removal.

  9. CO2-DISSOLVED and Aqueous Gas Separation

    OpenAIRE

    Gorensek, Maximillian; Hamm, Luther; Blount, Gerald; Kervévan, Christophe; O'Neil, Kathleen

    2016-01-01

    International audience; CO2-DISSOLVED (Kervévan et al, 2014) is a multinational project funded by the French National Research Agency (ANR) with Phase II funded as one of the first Geodenergies projects. Geodenergies is a French industry-driven initiative grouping 18 companies and research organizations aiming at: (1) structuring a community of expertise to promote subsurface energy technologies that are key to a global energy transition; (2) cross-fertilizing to develop 3 emerging industrial...

  10. A NOVEL CO2 SEPARATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. Copeland; Gokhan Alptekin; Mike Cesario; Steven Gebhard; Yevgenia Gershanovich

    1999-01-01

    Because of concern over global climate change, new systems are needed that produce electricity from fossil fuels and emit less CO{sub 2}. The fundamental problem with current CO{sub 2} separation systems is the need to separate dilute CO{sub 2} and pressurize it for storage or sequestration. This is an energy intensive process that can reduce plant efficiency by 9-37% and double the cost of electricity.

  11. 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.

  12. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  13. CO2 Fixation by Membrane Separated NaCl Electrolysis

    Directory of Open Access Journals (Sweden)

    Hyun Sic Park

    2015-08-01

    Full Text Available Atmospheric concentrations of carbon dioxide (CO2, a major cause of global warming, have been rising due to industrial development. Carbon capture and storage (CCS, which is regarded as the most effective way to reduce such atmospheric CO2 concentrations, has several environmental and technical disadvantages. Carbon capture and utilization (CCU, which has been introduced to cover such disadvantages, makes it possible to capture CO2, recycling byproducts as resources. However, CCU also requires large amounts of energy in order to induce reactions. Among existing CCU technologies, the process for converting CO2 into CaCO3 requires high temperature and high pressure as reaction conditions. This study proposes a method to fixate CaCO3 stably by using relatively less energy than existing methods. After forming NaOH absorbent solution through electrolysis of NaCl in seawater, CaCO3 was precipitated at room temperature and pressure. Following the experiment, the resulting product CaCO3 was analyzed with Fourier transform infrared spectroscopy (FT-IR; field emission scanning electron microscopy (FE-SEM image and X-ray diffraction (XRD patterns were also analyzed. The results showed that the CaCO3 crystal product was high-purity calcite. The study shows a successful method for fixating CO2 by reducing carbon dioxide released into the atmosphere while forming high-purity CaCO3.

  14. Amorphous Silk Fibroin Membranes for Separation of CO2

    Science.gov (United States)

    Aberg, Christopher M.; Patel, Anand K.; Gil, Eun Seok; Spontak, Richard J.; Hagg, May-Britt

    2009-01-01

    Amorphous silk fibroin has shown promise as a polymeric material derivable from natural sources for making membranes for use in removing CO2 from mixed-gas streams. For most applications of silk fibroin, for purposes other than gas separation, this material is used in its highly crystalline, nearly natural form because this form has uncommonly high tensile strength. However, the crystalline phase of silk fibroin is impermeable, making it necessary to convert the material to amorphous form to obtain the high permeability needed for gas separation. Accordingly, one aspect of the present development is a process for generating amorphous silk fibroin by treating native silk fibroin in an aqueous methanol/salt solution. The resulting material remains self-standing and can be prepared as thin film suitable for permeation testing. The permeability of this material by pure CO2 has been found to be highly improved, and its mixed-gas permeability has been found to exceed the mixed-gas permeabilities of several ultrahigh-CO2-permeable synthetic polymers. Only one of the synthetic polymers poly(trimethylsilylpropyne) [PTMSP] may be more highly permeable by CO2. PTMSP becomes unstable with time, whereas amorphous silk should not, although at the time of this reporting this has not been conclusively proven.

  15. Capture and separation of CO2 from flue gas by coupling free and immobilized amines.

    Science.gov (United States)

    Shi, Yao; Li, Wei

    2002-10-01

    A novel system was proposed for the capture and separation of CO2 from flue gas. In this method, a resin was employed to regenerate the amine capturing CO2 from flue gas at room temperature. The feasibility for the resin to regenerate amines such as MEA, MAE, TEA, and ammonia was demonstrated. It was also discovered that the resin could be regenerated by hot water.

  16. Evaluation of Mars CO2 Capture and Gas Separation Technologies

    Science.gov (United States)

    Muscatello, Anthony C.; Santiago-Maldonado, Edgardo; Gibson, Tracy; Devor, Robert; Captain, James

    2011-01-01

    Recent national policy statements have established that the ultimate destination of NASA's human exploration program is Mars. In Situ Resource Utilization (ISRU) is a key technology required to ,enable such missions and it is appropriate to review progress in this area and continue to advance the systems required to produce rocket propellant, oxygen, and other consumables on Mars using the carbon dioxide atmosphere and other potential resources. The Mars Atmospheric Capture and Gas separation project is selecting, developing, and demonstrating techniques to capture and purify Martian atmospheric gases for their utilization for the production of hydrocarbons, oxygen, and water in ISRU systems. Trace gases will be required to be separated from Martian atmospheric gases to provide pure CO2 to processing elements. In addition, other Martian gases, such as nitrogen and argon, occur in concentrations high enough to be useful as buffer gas and should be captured as well. To achieve these goals, highly efficient gas separation processes will be required. These gas separation techniques are also required across various areas within the ISRU project to support various consumable production processes. The development of innovative gas separation techniques will evaluate the current state-of-the-art for the gas separation required, with the objective to demonstrate and develop light-weight, low-power methods for gas separation. Gas separation requirements include, but are not limited to the selective separation of: (1) methane and water from unreacted carbon oxides (C02-CO) and hydrogen typical of a Sabatier-type process, (2) carbon oxides and water from unreacted hydrogen from a Reverse Water-Gas Shift process, (3)/carbon oxides from oxygen from a trash/waste processing reaction, and (4) helium from hydrogen or oxygen from a propellant scavenging process. Potential technologies for the separations include' freezers, selective membranes, selective solvents, polymeric sorbents

  17. Computational Studies of CO 2 Sorption and Separation in an Ultramicroporous Metal–Organic Material

    KAUST Repository

    Forrest, Katherine A.

    2013-08-29

    Grand canonical Monte Carlo (GCMC) simulations of CO2 sorption and separation were performed in [Zn(pyz)2SiF6], a metal-organic material (MOM) consisting of a square grid of Zn2+ ions coordinated to pyrazine (pyz) linkers and pillars of SiF6 2- ions. This MOM was recently shown to have an unprecedented selectivity for CO2 over N2, CH4, and H 2 under industrially relevant conditions. The simulated CO 2 sorption isotherms and calculated isosteric heat of adsorption, Qst, values were in excellent agreement with the experimental data for all the state points considered. CO2 saturation in [Zn(pyz) 2SiF6] was achieved at near-ambient temperatures and pressures lower than 1.0 atm. Moreover, the sorbed CO2 molecules were representative of a liquid/fluid under such conditions as confirmed through calculating the isothermal compressibility, βT, values. The simulated CO2 uptakes within CO2/N2 (10:90), CO2/CH4 (50:50), and CO2/H2 (30:70) mixture compositions, characteristic of flue gas, biogas, and syngas, respectively, were comparable to those that were produced in the single-component CO2 sorption simulations. The modeled structure at saturation revealed a loading of 1 CO2 molecule per unit cell. The favored CO2 sorption site was identified as the attraction of the carbon atoms of CO2 molecules to four equatorial fluorine atoms of SiF6 2- anions simultaneously, resulting in CO2 molecules localized at the center of the channel. Furthermore, experimental studies have shown that [Zn(pyz)2SiF6] sorbed minimal amounts of CO2 and N2 at their respective liquid temperatures. Analysis of the crystal structure at 100 K revealed that the unit cell undergoes a slight contraction in all dimensions and contains pyrazine rings that are mildly slanted with an angle of 13.9. Additionally, molecular dynamics (MD) simulations revealed that the sorbate molecules are anchored to the framework at low temperatures, which inhibits diffusion. Thus, it is hypothesized that the sorbed molecules

  18. Functionalized Mesoporous Silica Membranes for CO2 Separation Applications

    Directory of Open Access Journals (Sweden)

    Hyung-Ju Kim

    2015-01-01

    Full Text Available Mesoporous silica molecular sieves are emerging candidates for a number of potential applications involving adsorption and molecular transport due to their large surface areas, high pore volumes, and tunable pore sizes. Recently, several research groups have investigated the potential of functionalized mesoporous silica molecular sieves as advanced materials in separation devices, such as membranes. In particular, mesoporous silica with a two- or three-dimensional pore structure is one of the most promising types of molecular sieve materials for gas separation membranes. However, several important challenges must first be addressed regarding the successful fabrication of mesoporous silica membranes. First, a novel, high throughput process for the fabrication of continuous and defect-free mesoporous silica membranes is required. Second, functionalization of mesopores on membranes is desirable in order to impart selective properties. Finally, the separation characteristics and performance of functionalized mesoporous silica membranes must be further investigated. Herein, the synthesis, characterization, and applications of mesoporous silica membranes and functionalized mesoporous silica membranes are reviewed with a focus on CO2 separation.

  19. Phase Separation Kinetics in Isopycnic Mixtures of H2O/CO2/Ethoxylated Alcohol Surfactants

    Science.gov (United States)

    Lesemann, Markus; Paulaitis, Michael E.; Kaler, Eric W.

    1999-01-01

    Ternary mixtures of H2O and CO2 with ethoxylated alcohol (C(sub i)E(sub j)) surfactants form three coexisting liquid phases at conditions where two of the phases have equal densities (isopycnic phases). Isopycnic phase behavior has been observed for mixtures containing C8E5, C10E6, and C12E6 surfactants, but not for those mixtures containing either C4E1 or C8E3 surfactants. Pressure-temperature (PT) projections for this three-phase equilibrium were determined for H2O/CO2/C8E5 and H2O/CO2/C10E6 mixtures at temperatures from approximately 25 to 33 C and pressures between 90 and 350 bar. Measurements of the microstructure in H2O/CO2/C12E6 mixtures as a function of temperature (25-31 C), pressure (63.1-90.7 bar), and CO2 composition (0-3.9 wt%) have also been carried out to show that while micellar structure remains essentially un-changed, critical concentration fluctuations increase as the phase boundary and plait point are approached. In this report, we present our first measurements of the kinetics of isopycnic phase separation for ternary mixtures of H2O/CO2/C8E5.

  20. Analysis of a New Liquefaction Combined with Desublimation System for CO2 Separation Based on N2/CO2 Phase Equilibrium

    Directory of Open Access Journals (Sweden)

    Wenchao Yang

    2015-09-01

    Full Text Available Cryogenic CO2 capture is considered as a promising CO2 capture method due to its energy saving and environmental friendliness. The phase equilibrium analysis of CO2-mixtures at low temperature is crucial for the design and operation of a cryogenic system because it plays an important role in analysis of recovery and purity of the captured CO2. After removal of water and toxic gas, the main components in typical boiler gases are N2/CO2. Therefore, this paper evaluates the reliabilities of different cubic equations of state (EOS and mixing rules for N2/CO2. The results show that Peng-Robinson (PR and Soave-Redlich-Kwong (SRK fit the experimental data well, PR combined with the van der Waals (vdW mixing rule is more accurate than the other models. With temperature decrease, the accuracy of the model improves and the deviation of the N2 vapor fraction is 0.43% at 220 K. Based on the selected calculation model, the thermodynamic properties of N2/CO2 at low temperature are analyzed. According to the results, a new liquefaction combined with a desublimation system is proposed. The total recovery and purity of CO2 production of the new system are satisfactory enough for engineering applications. Additionally, the total energy required by the new system to capture the CO2 is about 3.108 MJ·kg−1 CO2, which appears to be at least 9% lower than desublimation separation when the initial concentration of CO2 is 40%.

  1. Novel CO2 Separation and Methanation for Oxygen and Fuel Production Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes a novel efficient, compact, and lightweight MicrolithREG-based CO2 separator and methanation reactor to separate CO2 from...

  2. A Superacid-Catalyzed Synthesis of Porous Membranes Based on Triazine Frameworks for CO2 Separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X; Tian, CC; Mahurin, SM; Chai, SH; Wang, CM; Brown, S; Veith, GM; Luo, HM; Liu, HL; Dai, S

    2012-06-27

    A general strategy for the synthesis of porous, fluorescent, triazine-framework-based membranes with intrinsic porosity through an aromatic nitrile trimerization reaction is presented. The essence of this strategy lies in the use of a superacid to catalyze the cross-linking reaction efficiently at a low temperature, allowing porous polymer membrane architectures to be facilely derived. With fiinctionalized triazine units, the membrane exhibits an increased selectivity for membrane separation of CO2 over N-2. The good ideal CO2/N-2 selectivity of 29 +/- 2 was achieved with a CO2 permeability of 518 +/- 25 barrer. Through this general synthesis protocol, a new class of porous polymer membranes with tunable functionalities and porosities can be derived, significantly expanding the currently limited library of polymers with intrinsic microporosity for synthesizing functional membranes in separation, catalysis, and energy storage/conversion.

  3. A superacid-catalyzed synthesis of porous membranes based on triazine frameworks for CO2 separation.

    Science.gov (United States)

    Zhu, Xiang; Tian, Chengcheng; Mahurin, Shannon M; Chai, Song-Hai; Wang, Congmin; Brown, Suree; Veith, Gabriel M; Luo, Huimin; Liu, Honglai; Dai, Sheng

    2012-06-27

    A general strategy for the synthesis of porous, fluorescent, triazine-framework-based membranes with intrinsic porosity through an aromatic nitrile trimerization reaction is presented. The essence of this strategy lies in the use of a superacid to catalyze the cross-linking reaction efficiently at a low temperature, allowing porous polymer membrane architectures to be facilely derived. With functionalized triazine units, the membrane exhibits an increased selectivity for membrane separation of CO(2) over N(2). The good ideal CO(2)/N(2) selectivity of 29 ± 2 was achieved with a CO(2) permeability of 518 ± 25 barrer. Through this general synthesis protocol, a new class of porous polymer membranes with tunable functionalities and porosities can be derived, significantly expanding the currently limited library of polymers with intrinsic microporosity for synthesizing functional membranes in separation, catalysis, and energy storage/conversion.

  4. Effects of elevated CO2 and temperature on seed quality

    OpenAIRE

    HAMPTON, J. G.; BOELT, B.; ROLSTON, M. P.; CHASTAIN, T. G.

    2012-01-01

    SUMMARY Successful crop production depends initially on the availability of high-quality seed. By 2050 global climate change will have influenced crop yields, but will these changes affect seed quality? The present review examines the effects of elevated carbon dioxide (CO2) and temperature during seed production on three seed quality components: seed mass, germination and seed vigour. In response to elevated CO2, seed mass has been reported to both increase and decrease in C3 plants, but not...

  5. Synthesis and characterization of ZIF-69 membranes and separation for CO2/CO mixture

    KAUST Repository

    Liu, Yunyang

    2010-05-01

    Continuous and c-oriented ZIF-69 membranes were successfully synthesized on porous alpha-alumina substrates by an in situ solvothermal method. The membranes were characterized by XRD, SEM and single-gas permeation tests. The BET measurements on crystals taken from the same mother liquor that was used for membrane synthesis yield a Langmuir surface area of 1138 m(2)/g. The stability of the membrane towards heat and different solvents were studied. Single-gas permeation experiments through ZIF-69 membranes were carried out by a vacuum method at room temperature using H-2, CH4, CO, CO2 and SF6, respectively. The permeances were in the order of H-2 > CO2 > CH4 > CO > SF6. The separation of CO2/CO gas mixture was investigated by gas chromatograph (GC) and the permselectivity of CO2/CO was 3.5 +/- 0.1 with CO2 permeance of 3.6 +/- 0.3 x 10(-8) mol m(-2) s(-1) Pa-1 at room temperature. (C) 2010 Elsevier B.V. All rights reserved.

  6. CO2 Plasticization of Polyethersulfone/Polyimide Gas-Separation Membranes

    NARCIS (Netherlands)

    Kapantaidakis, G.; Koops, G.H.; Wessling, Matthias; Kaldis, S.P.; Sakellaropoulos, G.P.

    2003-01-01

    This work reports the CO2 plasticization of gas-separation hollow-fiber membranes based on polyimide and polyethersulfone blends. The feed pressure effect on the permeance of pure gases (CO2, N2) and the separation performance of a gaseous mixture (CO2/N2, 55/45%) is examined. Contrary to dense

  7. Modeling Silicate Weathering for Elevated CO2 and Temperature

    Science.gov (United States)

    Bolton, E. W.

    2016-12-01

    A reactive transport model (RTM) is used to assess CO2 drawdown by silicate weathering over a wide range of temperature, pCO2, and infiltration rates for basalts and granites. Although RTM's have been used extensively to model weathering of basalts and granites for present-day conditions, we extend such modeling to higher CO2 that could have existed during the Archean and Proterozoic. We also consider a wide range of surface temperatures and infiltration rates. We consider several model basalt and granite compositions. We normally impose CO2 in equilibrium with the various atmospheric ranges modeled and CO2 is delivered to the weathering zone by aqueous transport. We also consider models with fixed CO2 (aq) throughout the weathering zone as could occur in soils with partial water saturation or with plant respiration, which can strongly influence pH and mineral dissolution rates. For the modeling, we use Kinflow: a model developed at Yale that includes mineral dissolution and precipitation under kinetic control, aqueous speciation, surface erosion, dynamic porosity, permeability, and mineral surface areas via sub-grid-scale grain models, and exchange of volatiles at the surface. Most of the modeling is done in 1D, but some comparisons to 2D domains with heterogeneous permeability are made. We find that when CO2 is fixed only at the surface, the pH tends toward higher values for basalts than granites, in large part due to the presence of more divalent than monovalent cations in the primary minerals, tending to decrease rates of mineral dissolution. Weathering rates increase (as expected) with increasing CO2 and temperature. This modeling is done with the support of the Virtual Planetary Laboratory.

  8. CO2 sorption of a ceramic separation membrane

    NARCIS (Netherlands)

    Wormeester, Herbert; Benes, Nieck Edwin; Spijksma, G.I.; Verweij, H.; Poelsema, Bene

    2004-01-01

    The ellipsometric characterization of the CO2 sorption of a silica membrane provides a fast and accurate technique for the characterization of maximum sorption and the heat of adsorption. Both parameters are evaluated for the 73 nm thick silica layer as well as the 1650 nm thick supporting γ-layer.

  9. 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.

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

    Science.gov (United States)

    Wang, Jun

    new series of oxygen-doped ACs were synthesized from polyfuran. Different factors that affect the AC formation were investigated, and two kinds of porogens (ZnC12 and KOH) and two active temperatures (600 and 800 °C) were tested. At 298K and 1bar, an excellent selectivity for separating CO2/N2 (41.7) and CO2/CH 4(6.8) gas mixture pairs was obtained on the PF-600 KOH. A breakthrough simulation was also performed to demonstrate the potential of industrial applications. The PF-600 KOH sample showed the best separation result in the simulated adsorption breakthrough as well. In chapter 4, quinone and hydroquinone on the surface of PF-600 ZnC1 2 were integrated. Significantly pore size shrinkage, improved CO 2/N2 and CO2/CH4 IAST selectivity were observed, which is 58.7% and 28.4 % higher than pristine porous carbon at 298K and 1 atm, respectively. In addition, transient breakthrough simulations for CO2/CH4/N2 binary mixtures were conducted in order to demonstrate the good separation performance in fixed bed adsorbers. In chapter 5, a novel nitrogen doped polymer poly(2-phenyl-1,3,6,8tetraazacyclodecane) will be used as the precursor to produce microporous N-doped activated carbons. Three activation temperatures (600, 700, and 800 °C) has been investigated with KOH as the porogen. High nitrogen content has been remained in the resultant carbon materials. Improved CO2 adsorption capacity and selectivites for the separation of CO2/CH4/N2 binary gas mixtures were achieved by the carbon adsorbents due to their N-containing groups, narrow pore size distribution, and large specific surface area. In chapter 6, MOF-derived activated carbons are developed from MIL-100(Al) as hard-template. Direct carbonization of MIL-100, MIL-100(Al)/F-127 composite, and MIL-100(Al)/KOH mixture has been investigated. Pore structure and surface morphology have been demonstrated. CO2/CH4/N2 binary selectivity, adsorption heats, and kinetic selectivity have been calculated. Breakthrough simulation

  11. Effects of elevated CO2 and temperature on seed quality

    DEFF Research Database (Denmark)

    Hampton, John G; Boelt, Birte; Rolston, M P

    2013-01-01

    Successful crop production depends initially on the availability of high-quality seed. By 2050 global climate change will have influenced crop yields, but will these changes affect seed quality? The present review examines the effects of elevated carbon dioxide (CO2) and temperature during seed...... species. Seed mass increases may result in a decrease of seed nitrogen (N) concentration in non-legumes. Increasing temperature may decrease seed mass because of an accelerated growth rate and reduced seed filling duration, but lower seed mass does not necessarily reduce seed germination or vigour. Like...... seed mass, reported seed germination responses to elevated CO2 have been variable. The reported changes in seed C/N ratio can decrease seed protein content which may eventually lead to reduced viability. Conversely, increased ethylene production may stimulate germination in some species. High-temperature...

  12. Separation of CO2 in a Solid Waste Management Incineration Facility Using Activated Carbon Derived from Pine Sawdust

    Directory of Open Access Journals (Sweden)

    Inés Durán

    2017-06-01

    Full Text Available The selective separation of CO2 from gas mixtures representative of flue gas generated in waste incineration systems is studied on two activated carbons obtained from pine sawdust and compared to a commercial activated carbon. Dynamic adsorption experiments were conducted in a fixed-bed adsorption column using a binary mixture (N2/CO2 with a composition representative of incineration streams at temperatures from 30 to 70 °C. The adsorption behavior of humid mixtures (N2/CO2/H2O was also evaluated in order to assess the influence of water vapor in CO2 adsorption at different relative humidity in the feed gas: 22% and 60%. Moreover, CO2 adsorption was studied in less favorable conditions, i.e., departing from a bed initially saturated with H2O. In addition, the effect of CO2 on H2O adsorption was examined. Experimental results showed that the CO2 adsorption capacity can be reduced significantly by the adsorption of H2O (up to 60% at high relative humidity conditions. On the other hand, the breakthrough tests over the adsorbent initially saturated with water vapor indicated that H2O is little affected by CO2 adsorption. The experimental results pointed out the biomass based carbons as best candidates for CO2 separation under incineration flue gas conditions.

  13. 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.

  14. 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.

  15. CO2 Separation Using Thermally Optimized Membranes: A Comprehensive Project Report (2000 - 2007)

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    2008-03-04

    This is a complete (Fiscal Years 2000–2006) collection of the Idaho National Laboratory’s (INL) research and development contributions to the project, “CO2 Separation Using Thermally Optimized Membranes.” The INL scientific contribution to the project has varied due to the fluctuations in funding from year to year. The focus of the project was polybenzimidazole (PBI) membranes and developing PBI compounds (both substitution and blends) that provide good film formation and gas separation membranes. The underlying problem with PBI is its poor solubility in common solvents. Typically, PBI is dissolved in “aggressive” solvents, like N,N-dimethylacetamide (DMAc) and N methylpyrrolidone (NMP). The INL FY-03 research was directed toward making soluble N-substituted PBI polymers, where INL was very successful. Many different types of modified PBI polymers were synthesized; however, film formation proved to be a big problem with both unsubstituted and N-substituted PBIs. Therefore, INL researchers directed their attention to using plasticizers or additives to make the membranes more stable and workable. During the course of these studies, other high-performance polymers (like polyamides and polyimides) were found to be better materials, which could be used either by themselves or blends with PBI. These alternative high-performance polymers provided the best pathway forward for soluble high-temperature polymers with good stable film formation properties. At present, the VTEC polyimides (product of RBI, Inc.) are the best film formers that exhibit high-temperature resistance. INL’s gas testing results show VTEC polyimides have very good gas selectivities for both H2/CO2 and CO2/CH4. Overall, these high-performance polymers pointed towards new research areas where INL has gained a greater understanding of polymer film formation and gas separation. These studies are making possible a direct approach to stable polymer-based high-temperature gas separation membranes

  16. CO2 Separation Using Thermally Optimized Membranes: A Comprehensive Project Report (2000 - 2007)

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Klaehn; C.J. Orme; E.S. Peterson; T.A. Luther; M.G. Jones; A.K. Wertsching

    2008-03-01

    This is a complete (Fiscal Years 2000–2006) collection of the Idaho National Laboratory’s (INL) research and development contributions to the project, “CO2 Separation Using Thermally Optimized Membranes.” The INL scientific contribution to the project has varied due to the fluctuations in funding from year to year. The focus of the project was polybenzimidazole (PBI) membranes and developing PBI compounds (both substitution and blends) that provide good film formation and gas separation membranes. The underlying problem with PBI is its poor solubility in common solvents. Typically, PBI is dissolved in “aggressive” solvents, like N,N-dimethylacetamide (DMAc) and N methylpyrrolidone (NMP). The INL FY-03 research was directed toward making soluble N-substituted PBI polymers, where INL was very successful. Many different types of modified PBI polymers were synthesized; however, film formation proved to be a big problem with both unsubstituted and N-substituted PBIs. Therefore, INL researchers directed their attention to using plasticizers or additives to make the membranes more stable and workable. During the course of these studies, other high-performance polymers (like polyamides and polyimides) were found to be better materials, which could be used either by themselves or blends with PBI. These alternative high-performance polymers provided the best pathway forward for soluble high-temperature polymers with good stable film formation properties. At present, the VTEC polyimides (product of RBI, Inc.) are the best film formers that exhibit high-temperature resistance. INL’s gas testing results show VTEC polyimides have very good gas selectivities for both H2/CO2 and CO2/CH4. Overall, these high-performance polymers pointed towards new research areas where INL has gained a greater understanding of polymer film formation and gas separation. These studies are making possible a direct approach to stable polymer-based high-temperature gas separation membranes

  17. 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

  18. Analysis of CO2 Separation from Flue Gas, Pipeline Transportation, and Sequestration in Coal

    Energy Technology Data Exchange (ETDEWEB)

    Eric P. Robertson

    2007-09-01

    This report was written to satisfy a milestone of the Enhanced Coal Bed Methane Recovery and CO2 Sequestration task of the Big Sky Carbon Sequestration project. The report begins to assess the costs associated with separating the CO2 from flue gas and then injecting it into an unminable coal seam. The technical challenges and costs associated with CO2 separation from flue gas and transportation of the separated CO2 from the point source to an appropriate sequestration target was analyzed. The report includes the selection of a specific coal-fired power plant for the application of CO2 separation technology. An appropriate CO2 separation technology was identified from existing commercial technologies. The report also includes a process design for the chosen technology tailored to the selected power plant that used to obtain accurate costs of separating the CO2 from the flue gas. In addition, an analysis of the costs for compression and transportation of the CO2 from the point-source to an appropriate coal bed sequestration site was included in the report.

  19. Use of reverse osmosis membranes for the separation of lemongrass essential oil and supercritical CO2

    Directory of Open Access Journals (Sweden)

    L.A.V. Sarmento

    2004-06-01

    Full Text Available Although it is still used very little by industry, the process of essential oil extraction from vegetable matrices with supercritical CO2 is regarded as a potentially viable technique. The operation of separating the extract from the solvent is carried out by reducing the pressure in the system. Separation by membranes is an alternative that offers lower energy consumption and easier operation than traditional methods of separation. Combining the processes essential oil extraction with supercritical CO2 and separation by membranes permits the separation of solvent and oil without the need for large variations in extraction conditions. This results in a large energy savings in the case of solvent repressurisation and reuse. In this study, the effectiveness of reverse osmosis membranes in separating lemongrass essential oil from mixtures with supercritical CO2 was tested. The effects of feed oil concentration and transmembrane pressure on CO2 permeate flux and oil retention were studied for three membrane models.

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

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

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

  1. Synthesis of asymmetric polyetherimide membrane for CO2/N2 separation

    Science.gov (United States)

    Ahmad, A. L.; Salaudeen, Y. O.; Jawad, Z. A.

    2017-06-01

    Large emission of carbon dioxide (CO2) to the environment requires mitigation to avoid unbearable consequences on global climate change. The CO2 emissions generated by fossil fuel combustion within the power and industrial sectors need to be quickly curbed. The gas emission can be abated using membrane technology; this is one of the most promising approaches for selective separation of CO2/N2. The purpose of the study is to synthesis an asymmetric polyetherimide (PEI) membrane and to establish its morphological characteristics for CO2/N2 separation. The PEI flat-sheet asymmetric membrane was fabricated using phase inversion with N-methyl-2-pyrrolidone (NMP) as solvent and water-isopropanol as a coagulant. Particularly, polymer concentration of 20, 25, and 30 wt. % were studied. In addition, the structure and morphology of the produced membrane were observed using scanning electron microscopy (SEM). Importantly, results showed that the membrane with high PEI concentration of 30 wt. % yield an optimal selectivity of 10.7 for CO2/Nitrogen (N2) separation at 1 bar and 25 ºC for pure gas, aided by the membrane surface morphology. The dense skin present was as a result of non-solvent (water) while isopropanol generates a porous sponge structure. This appreciable separation performance makes the PEI asymmetric membrane an attractive alternative for CO2/N2 separation.

  2. Graphene Oxide Membranes with Heterogeneous Nanodomains for Efficient CO2 Separations.

    Science.gov (United States)

    Wang, Shaofei; Xie, Yu; He, Guangwei; Xin, Qingping; Zhang, Jinhui; Yang, Leixin; Li, Yifan; Wu, Hong; Zhang, Yuzhong; Guiver, Michael D; Jiang, Zhongyi

    2017-11-06

    Achieving high membrane performance in terms of gas permeance and carbon dioxide selectivity is an important target in carbon capture. Aiming to manipulate the channel affinity towards CO2 to implement efficient separations, gas separation membranes containing CO2 -philic and non-CO2 -philic nanodomains in the interlayer channels of graphene oxide (GO) were formed by intercalating poly(ethylene glycol) diamines (PEGDA). PEGDA reacts with epoxy groups on the GO surface, constructing CO2 -philic nanodomains and rendering a high sorption capacity, whereas unreacted GO surfaces give non-CO2 -philic nanodomains, rendering low-friction diffusion. Owing to the orderly stacking of nanochannels through cross-linking and the heterogeneous nanodomains with moderate CO2 affinity, a GO-PEGDA500 membrane exhibits a high CO2 permeance of 175.5 GPU and a CO2 /CH4 selectivity of 69.5, which is the highest performance reported for dry-state GO-stacking membranes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Upgrading biogas by a low-temperature CO2 removal techni

    Directory of Open Access Journals (Sweden)

    Ahmed M.I. Yousef

    2016-06-01

    Full Text Available Biogas, a renewable energy source, is primarily composed of methane and carbon dioxide and other gaseous species. Biogas upgrading for removing CO2 from raw biogas is a necessary step before the biogas to be used as vehicle fuel or injected into the natural gas grid. Therefore, the present work aimed to propose a low-temperature CO2 removal process as an alternative to the conventional biogas upgrading technologies (water scrubbing, chemical and physical scrubbing, membranes and Pressure swing adsorption. A typical model biogas mixture of 60 mol.% CH4 and 40 mol.% CO2 is considered. The present process showed that a product purity of 94.5 mol.% CH4 is obtained from compressed biogas by combining distillation, flash separation, auxiliary refrigeration and internal heat recovery with a potential specific energy consumption of 0.26 kW h/Nm3 raw biogas. The process has been simulated in Aspen HYSYS with avoiding the occurrence of CO2 freeze-out. The process delivers the captured CO2 in liquid form with a purity of 99.7 mol.% as a by-product for transport at 110 bar. It is concluded that the proposed upgrading process can serve as a new environmentally friendly approach to CO2 removal with an interesting energy-efficient alternative to the conventional upgrading techniques.

  4. Porous materials with optimal adsorption thermodynamics and kinetics for CO2 separation.

    Science.gov (United States)

    Nugent, Patrick; Belmabkhout, Youssef; Burd, Stephen D; Cairns, Amy J; Luebke, Ryan; Forrest, Katherine; Pham, Tony; Ma, Shengqian; Space, Brian; Wojtas, Lukasz; Eddaoudi, Mohamed; Zaworotko, Michael J

    2013-03-07

    The energy costs associated with the separation and purification of industrial commodities, such as gases, fine chemicals and fresh water, currently represent around 15 per cent of global energy production, and the demand for such commodities is projected to triple by 2050 (ref. 1). The challenge of developing effective separation and purification technologies that have much smaller energy footprints is greater for carbon dioxide (CO2) than for other gases; in addition to its involvement in climate change, CO2 is an impurity in natural gas, biogas (natural gas produced from biomass), syngas (CO/H2, the main source of hydrogen in refineries) and many other gas streams. In the context of porous crystalline materials that can exploit both equilibrium and kinetic selectivity, size selectivity and targeted molecular recognition are attractive characteristics for CO2 separation and capture, as exemplified by zeolites 5A and 13X (ref. 2), as well as metal-organic materials (MOMs). Here we report that a crystal engineering or reticular chemistry strategy that controls pore functionality and size in a series of MOMs with coordinately saturated metal centres and periodically arrayed hexafluorosilicate (SiF(2-)(6)) anions enables a 'sweet spot' of kinetics and thermodynamics that offers high volumetric uptake at low CO2 partial pressure (less than 0.15 bar). Most importantly, such MOMs offer an unprecedented CO2 sorption selectivity over N2, H2 and CH4, even in the presence of moisture. These MOMs are therefore relevant to CO2 separation in the context of post-combustion (flue gas, CO2/N2), pre-combustion (shifted synthesis gas stream, CO2/H2) and natural gas upgrading (natural gas clean-up, CO2/CH4).

  5. Porous materials with optimal adsorption thermodynamics and kinetics for CO2 separation

    KAUST Repository

    Nugent, Patrick S.

    2013-02-27

    The energy costs associated with the separation and purification of industrial commodities, such as gases, fine chemicals and fresh water, currently represent around 15 per cent of global energy production, and the demand for such commodities is projected to triple by 2050 (ref. 1). The challenge of developing effective separation and purification technologies that have much smaller energy footprints is greater for carbon dioxide (CO2) than for other gases; in addition to its involvement in climate change, CO 2 is an impurity in natural gas, biogas (natural gas produced from biomass), syngas (CO/H 2, the main source of hydrogen in refineries) and many other gas streams. In the context of porous crystalline materials that can exploit both equilibrium and kinetic selectivity, size selectivity and targeted molecular recognition are attractive characteristics for CO 2 separation and capture, as exemplified by zeolites 5A and 13X (ref. 2), as well as metal-organic materials (MOMs). Here we report that a crystal engineering or reticular chemistry strategy that controls pore functionality and size in a series of MOMs with coordinately saturated metal centres and periodically arrayed hexafluorosilicate (SiF 6 2-) anions enables a \\'sweet spot\\' of kinetics and thermodynamics that offers high volumetric uptake at low CO2 partial pressure (less than 0.15 bar). Most importantly, such MOMs offer an unprecedented CO 2 sorption selectivity over N2, H 2 and CH 4, even in the presence of moisture. These MOMs are therefore relevant to CO2 separation in the context of post-combustion (flue gas, CO2/N2), pre-combustion (shifted synthesis gas stream, CO 2/H 2) and natural gas upgrading (natural gas clean-up, CO2/CH 4). © 2013 Macmillan Publishers Limited. All rights reserved.

  6. Analysis of a New Liquefaction Combined with Desublimation System for CO2 Separation Based on N2/CO2 Phase Equilibrium

    OpenAIRE

    Wenchao Yang; Shuhong Li; Xianliang Li; Yuanyuan Liang; Xiaosong Zhang

    2015-01-01

    Cryogenic CO2 capture is considered as a promising CO2 capture method due to its energy saving and environmental friendliness. The phase equilibrium analysis of CO2-mixtures at low temperature is crucial for the design and operation of a cryogenic system because it plays an important role in analysis of recovery and purity of the captured CO2. After removal of water and toxic gas, the main components in typical boiler gases are N2/CO2. Therefore, this paper evaluates the reliabilities of diff...

  7. 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.

  8. A microporous metal-organic framework for selective C2H2 and CO2 separation

    Science.gov (United States)

    Lin, Rong-Guang; Lin, Rui-Biao; Chen, Banglin

    2017-08-01

    A quartzlike metal-organic framework with interesting one dimensional channel has been synthesized. It exhibits considerable acetylene and carbon dioxide uptake of 41.5 and 24.6 cm3 g-1, respectively, and relatively high selectivity for separation of C2H2/C2H4, C2H2/CH4, CO2/CH4 and CO2/N2 at ambient condition.

  9. Ultem®/ZIF-8 mixed matrix hollow fiber membranes for CO2/N2 separations

    KAUST Repository

    Dai, Ying

    2012-05-01

    Organic-inorganic hybrid (mixed matrix) membranes can potentially extend the separation performance of traditional polymeric materials while maintaining processing convenience. Although many dense films studies have been reported, there have been few reported cases of these materials being successfully extended to asymmetric hollow fibers. In this work we report the first successful production of mixed matrix asymmetric hollow fiber membranes containing metal-organic-framework (MOF) ZIF-8 fillers. Specifically, we have incorporated ZIF-8 into a polyetherimide (Ultem ® 1000) matrix and produced dual-layer asymmetric hollow fiber membranes via the dry jet-wet quench method. The outer separating layer of these composite fibers contains 13wt% (17vol%) of ZIF-8 filler. These membranes have been tested over a range of temperatures and pressures for a variety of gas pairs. An increase in separation performance for the CO 2/N 2 gas pairs was observed for both pure gas and mixed gas feeds. © 2012 Elsevier B.V.

  10. 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.

  11. Response of microalgae to elevated CO2 and temperature: impact of climate change on freshwater ecosystems.

    Science.gov (United States)

    Li, Wei; Xu, Xiaoguang; Fujibayashi, Megumu; Niu, Qigui; Tanaka, Nobuyuki; Nishimura, Osamu

    2016-10-01

    To estimate the combined effects of elevated CO2 and temperature on microalgae, three typical and worldwide freshwater species, the green alga Scenedesmus acuminatus, the diatom Cyclotella meneghiniana, and the cyanobacterium Microcystis aeruginosa, as well as mixes of these three species were continuously cultured in controlled environment chambers with CO2 at 390 and 1000 ppm and temperatures of 20, 25, and 30 °C. CO2 and temperature significantly affected the production of microalgae. The cell productivity increased under elevated CO2 and temperature. Although the green alga dominated in the mixed culture within all CO2 and temperature conditions, rising temperature and CO2 intensified the competition of the cyanobacterium with other microalgae. CO2 affected the extracellular polymeric substances (EPS) characteristics of the green alga and the cyanobacterium. Elevated CO2 induced the generation of humic substances in the EPS fractions of the green alga, the cyanobacterium, and the mixed culture. The extracellular carbohydrates of the diatom and the extracellular proteins of the cyanobacterium increased with elevated CO2 and temperature, while the extracellular carbohydrates and proteins of the green alga and the mixes increased under elevated CO2 and temperature. There were synergistic effects of CO2 and temperature on the productivity and the EPS of microalgae. Climate change related CO2 and temperature increases will promote autochthonous organic carbon production in aquatic ecosystems and facilitate the proliferation of cyanobacteria, which potentially changes the carbon cycling and undermines the functioning of ecosystems.

  12. 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.

  13. Small CO2 Sensors Operate at Lower Temperature

    Science.gov (United States)

    Hunter, Gary W.; Xu, Jennifer C.

    2009-01-01

    Solid-electrolyte-based amperometric sensors for measuring concentrations of CO2 in air are being developed for use in detection of fires, environmental monitoring, and other applications where liquid-based electrochemical cells are problematic. These sensors are small (sizes of the order of a millimeter), are robust, are amenable to batch fabrication at relatively low cost, and exhibit short response times (seconds) and wide detection ranges. A sensor of this type at a previous stage of development included a solid electrolyte of Na3Zr2Si2PO12 deposited mainly between interdigitated Pt electrodes on an alumina substrate, all overcoated with an auxiliary solid electrolyte of (Na2CO3:BaCO3 in a molar ratio of 1:1.7). It was necessary to heat this device to a temperature as high as 600 C to obtain the desired sensitivity and rapid response. Heating sensors increases the power consumption of the sensor system and complicates the use of the sensor in some applications. Thus, decreasing a sensor s power consumption while maintaining its performance is a technical goal of ongoing development.

  14. Interactions between temperature and intercellular CO2 concentration in controlling leaf isoprene emission rates

    National Research Council Canada - National Science Library

    Monson, Russell K; Neice, Amberly A; Trahan, Nicole A; Shiach, Ian; McCorkel, Joel T; Moore, David J.P

    2016-01-01

    .... Evidence exists from a limited set of past observations that isoprene emission rate (I s ) decreases as a function of increasing atmospheric CO 2 concentration, and that increased temperature suppresses the CO 2 effect...

  15. Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

    Science.gov (United States)

    Monroe, Morgan M.; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W.

    2017-04-01

    The production of liquid fuel products via electrochemical reduction of CO2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O2) from reaching the cathode. Ion-conducting membranes have been applied in CO2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved.

  16. Optimized CO2-flue gas separation model for a coal fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Arachchige, Udara S.P.R. [Telemark University College, Porsgrunn (Norway); Mohsin, Muhammad [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The detailed description of the CO2 removal process using mono-ethylamine (MEA) as a solvent for coal-fired power plant is present in this paper. The rate based Electrolyte NRTL activity coefficient model was used in the Aspen Plus. The complete removal process with re-circulating solvent back to the absorber was implemented with the sequential modular method in Aspen Plus. The most significant cost related to CO2 capture is the energy requirement for re-generating solvent, i.e. re-boiler duty. Parameters’ effects on re-boiler duty were studied, resulting decreased re-boiler duty with the packing height and absorber packing diameter, absorber pressure, solvent temperature, stripper packing height and diameter. On the other hand, with the flue gas temperature, re-boiler duty is increased. The temperature profiles and CO2 loading profiles were used to check the model behavior.

  17. Microbial electrolytic capture, separation and regeneration of CO2 for biogas upgrading

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Zhang, Yifeng; Li, Xiaohu

    2017-01-01

    Biogas upgrading to natural gas quality is essential for the efficient use of biogas in various applications. Carbon dioxide (CO2) which constitutes a major part of the biogas is generally removed by physicochemical methods. However, most of the methods are expensive and often present environmental...... challenges. In this study, an innovative microbial electrolytic system was developed to capture, separate and regenerate CO2 for biogas upgrading without external supply of chemicals, and potentially to treat wastewater. The new system was operated at varied biogas flow rates and external applied voltages...

  18. Ionic Liquid Confined in Mesoporous Polymer Membrane with Improved Stability for CO2/N2 Separation

    Directory of Open Access Journals (Sweden)

    Ming Tan

    2017-09-01

    Full Text Available Supported ionic liquid membranes (SILMs have a promising prospect of application in flue gas separation, owing to its high permeability and selectivity of CO2. However, existing SILMs have the disadvantage of poor stability due to the loss of ionic liquid from the large pores of the macroporous support. In this study, a novel SILM with high stability was developed by confining ionic liquid in a mesoporous polymer membrane. First, a mesoporous polymer membrane derived from a soluble, low-molecular-weight phenolic resin precursor was deposited on a porous Al2O3 support, and then 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4] was immobilized inside mesopores of phenolic resin, forming the SILM under vacuum. Effects of trans-membrane pressure difference on the SILM separation performance were investigated by measuring the permeances of CO2 and N2. The SILM exhibits a high ideal CO2/N2 selectivity of 40, and an actual selectivity of approximately 25 in a mixed gas (50% CO2 and 50% N2 at a trans-membrane pressure difference of 2.5 bar. Compared to [emim][BF4] supported by polyethersulfone membrane with a pore size of around 0.45 μm, the [emim][BF4] confined in a mesoporous polymer membrane exhibits an improved stability, and its separation performance remained stable for 40 h under a trans-membrane pressure difference of 1.5 bar in a mixed gas before the measurement was intentionally stopped.

  19. CO2 Capture and Separation Properties in the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Nonafluorobutylsulfonate

    Directory of Open Access Journals (Sweden)

    Lingyun Zhou

    2014-05-01

    Full Text Available Recently, the use of ionic liquids (ILs for carbon capture and separation processes has gained great interest by many researchers due to the high solubility of CO2 in ILs. In the present work, solubility measurements of CO2 in the novel IL 1-n-butyl-3-methylimidazolium nonafluorobutylsulfonate [C4mim][CF3CF2CF2CF2SO3] were performed with a high-pressure view-cell technique in the temperature range from 293.15 to 343.15 K and pressures up to about 4.2 MPa. For comparison, solubilities of H2, N2, and O2 in the IL were also measured at 323.15 K via the same procedure. The Krichevsky-Kasarnovsky equation was employed to correlate the measured solubility data. Henry’s law constants, enthalpies, and entropies of absorption for CO2 in the IL were also determined and presented. The CO2 solubility in this IL was compared with other ILs sharing the same cation. It was shown that the solubility of CO2 in these ILs follows the sequence: [C4mim][CF3CF2CF2CF2SO3] ≈ [C4mim][Tf2N] > [C4mim][CF3CF2CF2COO] > [C4mim][BF4], and the solubility selectivity of CO2 relative to O2, N2, and H2 in [C4mim][CF3CF2CF2CF2SO3] was 8, 16, and 22, respectively. Furthermore, this IL is regenerable and exhibits good stability. Therefore, the IL reported here would be a promising sorbent for CO2.

  20. Computational evaluation of aluminophosphate zeotypes for CO2/N2 separation.

    Science.gov (United States)

    Fischer, Michael

    2017-08-30

    Zeolites and structurally related materials (zeotypes) have received considerable attention as potential adsorbents for selective carbon dioxide adsorption. Within this group, zeotypes with aluminophosphate composition (AlPOs) could be an interesting alternative to the more frequently studied aluminosilicate zeolites. So far, however, only a few AlPOs have been characterised experimentally in terms of their CO2 adsorption properties. In this study, force-field based grand-canonical Monte Carlo (GCMC) simulations were used to evaluate the potential of AlPOs for CO2/N2 separation, a binary mixture that constitutes a suitable model system for the removal of carbon dioxide from flue gases. A total of 51 frameworks were considered, all of which have been reported either as pure AlPOs or as heteroatom-containing AlPO derivatives. Prior to the GCMC simulations, all structures were optimised using dispersion-corrected density-functional theory calculations. The potential of these 51 systems for CO2/N2 separation was assessed in preliminary calculations (Henry constants and CO2 uptake at selected pressures). On the basis of these calculations, 21 AlPOs of particular interest were selected, for which 15 : 85 CO2/N2 mixture adsorption isotherms were calculated up to 10 bar. For adsorption-based separations using an adsorption pressure of 1 bar (vacuum-swing adsorption), AlPOs with GIS, ATN, ATT, and SIV topologies were predicted to be most attractive, as they combine high CO2/N2 selectivities (75 to 140) and reasonable CO2 working capacities (1 to 1.7 mmol g-1). Under pressure-swing adsorption conditions, there is a tradeoff between selectivity and working capacity: while highly selective AlPOs like GIS reach only moderate working capacities, the frameworks with the highest working capacities above 2 mmol g-1, AFY, KFI, and SAV, have lower selectivities between 25 and 35. To gain atomic-level insights into the host-guest interactions, interaction energy maps were computed

  1. Directing the structural features of N(2)-phobic nanoporous covalent organic polymers for CO(2) capture and separation.

    Science.gov (United States)

    Patel, Hasmukh A; Je, Sang Hyun; Park, Joonho; Jung, Yousung; Coskun, Ali; Yavuz, Cafer T

    2014-01-13

    A family of azo-bridged covalent organic polymers (azo-COPs) was synthesized through a catalyst-free direct coupling of aromatic nitro and amine compounds under basic conditions. The azo-COPs formed 3D nanoporous networks and exhibited surface areas up to 729.6 m(2)  g(-1) , with a CO2 -uptake capacity as high as 2.55 mmol g(-1) at 273 K and 1 bar. Azo-COPs showed remarkable CO2 /N2 selectivities (95.6-165.2) at 298 K and 1 bar. Unlike any other porous material, CO2 /N2 selectivities of azo-COPs increase with rising temperature. It was found that azo-COPs show less than expected affinity towards N2 gas, thus making the framework "N2 -phobic", in relative terms. Our theoretical simulations indicate that the origin of this unusual behavior is associated with the larger entropic loss of N2 gas molecules upon their interaction with azo-groups. The effect of fused aromatic rings on the CO2 /N2 selectivity in azo-COPs is also demonstrated. Increasing the π-surface area resulted in an increase in the CO2 -philic nature of the framework, thus allowing us to reach a CO2 /N2 selectivity value of 307.7 at 323 K and 1 bar, which is the highest value reported to date. Hence, it is possible to combine the concepts of "CO2 -philicity" and "N2 -phobicity" for efficient CO2 capture and separation. Isosteric heats of CO2 adsorption for azo-COPs range from 24.8-32.1 kJ mol(-1) at ambient pressure. Azo-COPs are stable up to 350 °C in air and boiling water for a week. A promising cis/trans isomerization of azo-COPs for switchable porosity is also demonstrated, making way for a gated CO2 uptake. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Improvement of CO2/N2 separation performance by polymer matrix cellulose acetate butyrate

    Science.gov (United States)

    Lee, R. J.; Jawad, Z. A.; Ahmad, A. L.; Ngo, J. Q.; Chua, H. B.

    2017-06-01

    With the rapid development of modern civilization, carbon dioxide (CO2) is produced in large quantities and mainly generated from industrial sectors. The gas emission is the major contributor to global warming. To address this issue, the membrane technology is implemented for the CO2 removal, due to the energy efficiency and economic advantages presented. Cellulose acetate butyrate (CAB) is selected as the polymeric material, due to the excellent film-forming properties and capable of developing a defect-free layer of neat membrane. This study described the fabrication development of CAB using a wet phase inversion method with different casting conditions. Where the composition of the casting solutions (3-5 wt %) and solvent evaporation time (4-6 min) were determined. The outcomes of these dominant parameters were then used to determine the best CAB membrane for CO2/Nitrogen (N2) separation and supported by the characterization i.e. scanning electron micrograph. Gas permeation measurements showed satisfactory performance for CAB membrane fabricated with 5 min evaporation time and 4 wt% polymer composition (M2). Where, its permeance and selectivity are 120.19 GPU and 3.17, respectively. In summary, this study showed a brief outlined of the future direction and perspective of CAB membrane for CO2/N2 separation.

  3. 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.

  4. The deep atmosphere of Venus and the possible role of density-driven separation of CO2 and N2

    Science.gov (United States)

    Lebonnois, Sebastien; Schubert, Gerald

    2017-07-01

    With temperatures around 700 K and pressures of around 75 bar, the deepest 12 km of the atmosphere of Venus are so hot and dense that the atmosphere behaves like a supercritical fluid. The Soviet VeGa-2 probe descended through the atmosphere in 1985 and obtained the only reliable temperature profile for the deep Venusian atmosphere thus far. In this temperature profile, the atmosphere appears to be highly unstable at altitudes below 7 km, contrary to expectations. We argue that the VeGa-2 temperature profile could be explained by a change in the atmospheric gas composition, and thus molecular mass, with depth. We propose that the deep atmosphere consists of a non-homogeneous layer in which the abundance of N2--the second most abundant constituent of the Venusian atmosphere after CO2--gradually decreases to near-zero at the surface. It is difficult to explain a decline in N2 towards the surface with known nitrogen sources and sinks for Venus. Instead we suggest, partly based on experiments on supercritical fluids, that density-driven separation of N2 from CO2 can occur under the high pressures of Venus's deep atmosphere, possibly by molecular diffusion, or by natural density-driven convection. If so, the amount of nitrogen in the atmosphere of Venus is 15% lower than commonly assumed. We suggest that similar density-driven separation could occur in other massive planetary atmospheres.

  5. Cyclic Carbonation Calcination Studies of Limestone and Dolomite for CO2 Separation From Combustion Flue Gases

    OpenAIRE

    Sivalingam, S.;Gleis, S.;Hartmut, S.;Yrjas, P.;Hupa, M.

    2017-01-01

    Naturally occurring limestone and dolomite samples, originating from different geographical locations, were tested as potential sorbents for carbonation/calcination based CO2 capture from combustion flue gases. Samples have been studied in a thermogravimetric analyzer under simulated flue gas conditions at three calcination temperatures,viz., 750textdegreeC, 875textdegreeC, and 930textdegreeC for four carbonation calcination reaction (CCR) cycles. The dolomite sample exhibited the highest rat...

  6. Polymer-silica hybrids for separation of CO2 and catalysis of organic reactions

    Science.gov (United States)

    Silva Mojica, Ernesto

    Porous materials comprising polymeric and inorganic segments have attracted interest from the scientific community due to their unique properties and functionalities. The physical and chemical characteristics of these materials can be effectively exploited for adsorption applications. This dissertation covers the experimental techniques for fabrication of poly(vinyl alcohol) (PVA) and silica (SiO2) porous supports, and their functionalization with polyamines for developing adsorbents with potential applications in separation of CO2 and catalysis of organic reactions. The supports were synthesized by processes involving (i) covalent cross-linking of PVA, (ii) hydrolysis and poly-condensation of silica precursors (i,e,. sol-gel synthesis), and formation of porous structures via (iii) direct templating and (iv) phase inversion techniques. Their physical structure was controlled by the proper combination of the preparation procedures, which resulted in micro-structured porous materials in the form of micro-particles, membranes, and pellets. Their adsorption characteristics were tailored by functionalization with polyethyleneimine (PEI), and their physicochemical properties were characterized by vibrational spectroscopy (FTIR, UV-vis), microscopy (SEM), calorimetry (TGA, DSC), and adsorption techniques (BET, step-switch adsorption). Spectroscopic investigations of the interfacial cross-linking reactions of PEI and PVA with glutaraldehyde (GA) revealed that PEI catalyzes the cross-linking reactions of PVA in absence of external acid catalysts. In-situ IR spectroscopy coupled with a focal plane array (FPA) image detector allowed the characterization of a gradient interface on a PEI/PVA composite membrane and the investigation of the cross-linking reactions as a function of time and position. The results served as a basis to postulate possible intermediates, and propose the reaction mechanisms. The formulation of amine-functionalized CO2 capture sorbents was based on the

  7. Influx of CO2 from Soil Incubated Organic Residues at Constant Temperature

    Directory of Open Access Journals (Sweden)

    Shoukat Ali Abro

    2016-06-01

    Full Text Available Temperature induced CO2 from genotypic residue substances is still less understood. Two types of organic residues (wheat- maize were incubated at a constant temperature (25°C to determine the rate and cumulative influx of CO2 in laboratory experiment for 40 days. Further, the effect of surface and incorporated crop residues with and without phosphorus addition was also studied. Results revealed that mixing of crop residues increased CO2-C evolution significantly & emission rare was 37% higher than that of control. At constant temperature, soil mixed residues, had higher emission rates CO2-C than the residues superimposed. There was linear correlation of CO2-C influxed for phosphorus levels and residue application ways with entire incubation at constant temperature. The mixing of organic residues to soil enhanced SOC levels and biomass of microbially bound N; however to little degree ammonium (NH4-N and nitrate NO3-N nitrogen were decreased.

  8. 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

  9. 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.

  10. Effects of elevated CO2 partial pressure and temperature on the coccolithophore Syracosphaera pulchra

    NARCIS (Netherlands)

    Fiorini, S.; Middelburg, J.J.; Gattuso, J.P.

    2011-01-01

    The effects of elevated partial pressure of CO2 (pCO2) and temperature on the cocco - lithophore Syracosphaera pulchra were investigated in isolation and in combination. Both the diploid and the haploid life stages were studied. Batch cultures were grown under 4 conditions: 400 μatm and 19°C; 400

  11. Coupling between atmospheric CO2 and temperature during the onset of the Little Ice Age

    NARCIS (Netherlands)

    Hoof, T.B. van

    2004-01-01

    Present day global warming is primarily caused by the greenhouse effect of the increased CO2 emissions since the onset of the industrial revolution. A coupling between temperature and the greenhouse gas CO2 has also been observed in several ice-core records on a glacial-interglacial timescale as

  12. Do elevated temperature and CO2 generally have counteracting effects on phenolic phytochemistry of boreal trees?

    Science.gov (United States)

    T.O. Veteli; W.J. Mattson; P. Niemela; R. Julkunen-Tiitto; S. Kellomaki; K. Kuokkanen; A. Lavola

    2007-01-01

    Global climate change includes concomitant changes in many components of the abiotic flux necessary for plant life. In this paper, we investigate the combined effects of elevated CO2 (720 ppm) and temperature (+2 K) on the phytochemistry of three deciduous tree species. The analysis revealed that elevated CO2 generally...

  13. In-situ grafting to improve polarity of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes for CO2 separation.

    Science.gov (United States)

    Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2018-01-15

    Surface grafting modification was proposed to improve the surface polarity of polyacrylonitrile hollow fiber-supported polydimethylsiloxane (PDMS) membrane. The initiator 3-aminopropyltriethoxysilane containing one amine group was integrated into PDMS, and polyvinyl pyrrolidone (PVP) with strong polarity was connected to the surface by reacting with amine groups. Surface grafting modification was proven on X-ray photoelectron spectroscopy. The sharp decrease (from ∼98° to ∼28°) in water contact angle of the PDMS membrane indicated the significant improvement in surface polarity after the modification. The surface roughness of the PDMS membrane increased with the modification, and the PDMS surface immersed for 40s was almost covered with PVP. The membrane immersed in PVP solution for 10s improved CO2/H2, CO2/CH4, and CO2/N2 selectivities. While CO2 permeance slightly decreased from ∼2500 GPU to ∼2440 GPU. For the separation of CO2/CH4 and CO2/N2 mixed gases, all CO2/CH4 and CO2/N2 selectivities were improved after the modification. For the separation of CO2/H2 mixed gas, CO2/H2 selectivity was improved when the immersion time was below 30 s. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Preparation of a carbon molecular sieve and application to separation of N2, O2 and CO2 in a fixed bed

    Directory of Open Access Journals (Sweden)

    Soares J.L.

    2003-01-01

    Full Text Available The emission of CO2 from power plants that burn fossil fuels is the major cause of the accumulation of CO2 in the atmosphere. The separation of CO2 from CO2/air mixtures can play a key role in alleviating this problem. This separation can be carried out by using suitable adsorbents, such as carbon molecular sieves. In this work, a CMS was prepared by deposition of polyfurfuryl alcohol polymer on activated carbon. After deposition of the polymer, the material was carbonized at 800masculineC for 2 hours. This material was used to separate O2/N2 mixtures and CO2 in a fixed bed at room temperature. Experimental breakthrough curves obtained were fitted to theoretical models in order to establish the main mechanisms of mass transfer. The breakthrough curves showed that it is possible to separate O2, N2 and CO2. The shape of the breakthrough curves was not influenced by the total flow, indicating that the gas contact for the gas mixture was good. The experimental data were fitted to theoretical models and it was established that the main mechanism of mass transfer was intraparticle diffusion.

  15. Temperature- and CO2-dependent life table parameters of Spodoptera litura (Noctuidae: Lepidoptera) on sunflower and prediction of pest scenarios.

    Science.gov (United States)

    Manimanjari, D; Srinivasa Rao, M; Swathi, P; Rama Rao, C A; Vanaja, M; Maheswari, M

    2014-01-01

    Predicted increase in temperature and atmospheric CO2 concentration will influence the growth of crop plants and phytophagous insects. The present study, conducted at the Central Research Institute for Dryland Agriculture, Hyderabad, India, aimed at (1) construction of life tables at six constant temperatures viz., 20, 25, 27, 30, 33, and 35 ± 0.5 °C for Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera) reared on sunflower (Helianthus annus L.) grown under ambient and elevated CO2 (eCO2) (550 ppm) concentration in open top chambers and (2) prediction of the pest status in near future (NF) and distant future (DF) climate change scenarios at major sunflower growing locations of India. Significantly lower leaf nitrogen, higher carbon and higher relative proportion of carbon to nitrogen (C:N) were observed in sunflower foliage grown under eCO2 over ambient. Feeding trials conducted on sunflower foliage obtained from two CO2 conditions showed that the developmental time of S. litura (Egg to adult) declined with increase in temperature and was more evident at eCO2. Finite (λ) and intrinsic rates of increase (r(m)), net reproductive rate (Ro), mean generation time, (T) and doubling time (DT) of S. litura increased significantly with temperature up to 27-30 °C and declined with further increase in temperature. Reduction of 'T' was observed from maximum value of 58 d at 20 °C to minimum of 24.9 d at 35 °C. The DT of population was higher (5.88 d) at 20 °C and lower (3.05 d) at 30 °C temperature of eCO2. The data on these life table parameters were plotted against temperature and two nonlinear models were developed separately for each of the CO2 conditions for predicting the pest scenarios. The NF and DF scenarios temperature data of four sunflower growing locations in India is based on PRECIS A1B emission scenario. It was predicted that increased 'rm', 'λ', and 'Ro' and reduced 'T' would occur during NF and DF scenario over present period at all

  16. 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

  17. Soil CO2 Flux, Moisture, Temperature, and Litterfall, La Selva, Costa Rica, 2003-2010

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurements of soil carbon dioxide (CO2) emission rates, soil moisture, relative humidity (RH), temperature, and litterfall from six types of...

  18. Preparation of a Facilitated Transport Membrane Composed of Carboxymethyl Chitosan and Polyethylenimine for CO2/N2 Separation

    Directory of Open Access Journals (Sweden)

    Jiang-Nan Shen

    2013-02-01

    Full Text Available The miscibility of carboxymethyl chitosan/polyethylenimine (CMCS/PEI blends was analyzed by FT-IR, TGA and SEM. Defect-free CMCS/PEI blend membranes were prepared with polysulfone (PSf ultrafiltration membranes as support layer for the separation of CO2/N2 mixtures. The results demonstrate that the CMCS/PEI blend is miscible, due to the hydrogen bonding interaction between the two targeted polymers. For the blended membrane without water, the permeability of CO2 gas is 3.6 × 10−7 cm3 cm−2 s−1 cmHg−1 and the corresponding separation factor for CO2 and N2 gas is about 33 at the pressure of 15.2 cmHg. Meanwhile, the blended membrane with water has the better permselectivity. The blended membrane containing water with PEI content of 30 wt% has the permeance of 6.3 × 10−4 cm3 cm−2 s−1 cmHg−1 for CO2 gas and a separation factor of 325 for CO2/N2 mixtures at the same feed pressure. This indicates that the CO2 separation performance of the CMCS/PEI blend membrane is higher than that of other facilitated transport membranes reported for CO2/N2 mixture separation.

  19. Preparation of a Facilitated Transport Membrane Composed of Carboxymethyl Chitosan and Polyethylenimine for CO2/N2 Separation.

    Science.gov (United States)

    Shen, Jiang-Nan; Yu, Chang-Chao; Zeng, Gan-Ning; van der Bruggen, Bart

    2013-02-07

    The miscibility of carboxymethyl chitosan/polyethylenimine (CMCS/PEI) blends was analyzed by FT-IR, TGA and SEM. Defect-free CMCS/PEI blend membranes were prepared with polysulfone (PSf) ultrafiltration membranes as support layer for the separation of CO(2)/N(2) mixtures. The results demonstrate that the CMCS/PEI blend is miscible, due to the hydrogen bonding interaction between the two targeted polymers. For the blended membrane without water, the permeability of CO(2) gas is 3.6 × 10-7 cm3 cm-2 s-1 cmHg-1 and the corresponding separation factor for CO(2) and N(2) gas is about 33 at the pressure of 15.2 cmHg. Meanwhile, the blended membrane with water has the better permselectivity. The blended membrane containing water with PEI content of 30 wt% has the permeance of 6.3 × 10-4 cm3 cm-2 s-1 cmHg-1 for CO(2) gas and a separation factor of 325 for CO(2)/N(2) mixtures at the same feed pressure. This indicates that the CO(2) separation performance of the CMCS/PEI blend membrane is higher than that of other facilitated transport membranes reported for CO(2)/N(2) mixture separation.

  20. Martian Liquid CO2 and Metabolic Heat Regenerated Temperature Swing Adsorption for Portable Life Support Systems

    Science.gov (United States)

    Iacomini, Christine; MacCallum, Taber; Morin, Tom; Straub-Lopez, Kathrine; Paul, Heather

    2007-01-01

    Two of the fundamental problems facing the development of a Portable Life Support System (PLSS) for use on Mars, are (i) heat rejection (because traditional technologies use sublimation of water, which wastes a scarce resource and contaminates the premises), and (ii) rejection of CO2 in an environment with a ppCO2 of 0.4-0.9 kPa. This paper presents a conceptual system for CO2 collection, compression, and cooling to produce sub-critical (liquid) CO2. A first order estimate of the system mass and energy to condense and store liquid CO2 outside at Mars ambient temperature at 600 kPa is discussed. No serious technical hurdles were identified and it is likely that better overall performance would be achieved if the system were part of an integrated ISRU strategy rather than a standalone system. Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology for CO2 removal from a PLSS vent loop, where the Martian liquid CO2 is used as the heat sink is developed to utilize the readily available liquid CO2. This paper will describe the technology and present data in support of its design.

  1. CO2 CAPTURE PROJECT - AN INTEGRATED, COLLABORATIVE TECHNOLOGY DEVELOPMENT PROJECT FOR NEXT GENERATION CO2 SEPARATION, CAPTURE AND GEOLOGIC SEQUESTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Helen Kerr

    2003-08-01

    The CO{sub 2} Capture Project (CCP) is a joint industry project, funded by eight energy companies (BP, ChevronTexaco, EnCana, Eni, Norsk Hydro, Shell, Statoil, and Suncor) and three government agencies (1) European Union (DG Res & DG Tren), (2) Norway (Klimatek) and (3) the U.S.A. (Department of Energy). The project objective is to develop new technologies, which could reduce the cost of CO{sub 2} capture and geologic storage by 50% for retrofit to existing plants and 75% for new-build plants. Technologies are to be developed to ''proof of concept'' stage by the end of 2003. The project budget is approximately $24 million over 3 years and the work program is divided into eight major activity areas: (1) Baseline Design and Cost Estimation--defined the uncontrolled emissions from each facility and estimate the cost of abatement in $/tonne CO{sub 2}. (2) Capture Technology, Post Combustion: technologies, which can remove CO{sub 2} from exhaust gases after combustion. (3) Capture Technology, Oxyfuel: where oxygen is separated from the air and then burned with hydrocarbons to produce an exhaust with high CO{sub 2} for storage. (4) Capture Technology, Pre -Combustion: in which, natural gas and petroleum coke are converted to hydrogen and CO{sub 2} in a reformer/gasifier. (5) Common Economic Model/Technology Screening: analysis and evaluation of each technology applied to the scenarios to provide meaningful and consistent comparison. (6) New Technology Cost Estimation: on a consistent basis with the baseline above, to demonstrate cost reductions. (7) Geologic Storage, Monitoring and Verification (SMV): providing assurance that CO{sub 2} can be safely stored in geologic formations over the long term. (8) Non-Technical: project management, communication of results and a review of current policies and incentives governing CO{sub 2} capture and storage. Technology development work dominated the past six months of the project. Numerous studies are making

  2. CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

    Directory of Open Access Journals (Sweden)

    Laura Nebot-Andrés

    2017-09-01

    Full Text Available A recent trend to spread the use of CO2 refrigeration cycles in warm regions of the world is to combine a CO2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. Both respond to a similar configuration of the refrigeration cycle, they being based on the use of two compressors and same number of heat exchangers. However, the compressor, heat exchanger sizes and energy performance differ a lot between them. This work, using experimental relations for CO2 and R1234yf semi-hermetic compressors analyzes in depth both alternatives under the warm climate of Spain. In general, it was concluded that the CO2 refrigeration solution with mechanical subcooling would cover all the conditions with high overall energy efficiency, thus it being recommended for further extension of the CO2 refrigeration applications.

  3. Low temperature CO2 mineralization into basalt: solution chemistry and secondary mineral assemblages

    Science.gov (United States)

    Gysi, A.; Stefánsson, A.

    2009-12-01

    CO2 represents one of the most abundant acid supplies in nature and has an important impact on element fluxes and water chemistry on the Earth surface. CO2 emissions due to increased industrialization are causing an important imbalance in this surface system and affect the global climate. Therefore, different methods to trap CO2 are developed and studied in response to the CO2 increase. CO2 sequestration into secondary minerals is considered as one possible way of reducing those CO2 levels. The Carbfix project is a pilot study in SW Iceland aiming to inject CO2-loaded waters from the Hellisheidi geothermal powerplant into basaltic rock formations. The goal is to mineralize CO2 by reacting Ca+2, Mg+2 and Fe+2 ions released by the basalt into carbonates. We investigated the geochemical aspects of CO2-water-basalt interaction at pCO2 between 0-20 bar and temperatures of 25-40°C by combining experiments and numerical modelling. The aim of our studies are to gain a better understanding of the key reactions, mass fluxes and porosity changes associated to CO2-water-basalt interaction. Modelling results show that at low reaction progress (pH 8) the main stable minerals precipitating from solution are (Ca)-Mg-Fe clays, Ca-Mg carbonates and zeolites (Gysi and Stéfansson 2008). Laboratory experiments were performed by reacting basaltic glass with aqueous solutions initially saturated at pCO2 ranging between 0-10 bar at 40°C for 120 days. Results from solution chemistry show that there are three different element mobility behaviors: i) Si+4 and Al+3 dissolve non-stochiometrically and/or precipitate into secondary minerals independent of the intial pCO2 and the water/rock ratios used in the experiments, b) Ca+2 and Mg+2 dissolve stochiometrically independent of the initial pCO2, but precipitate into secondary minerals at high water/rock ratios and low initial pCO2 after about 100 days, c) elements like Fe show a mixed behavior from mobile to immobile depending on the

  4. Dynamics of temperature normalized stem CO2 efflux in Norway spruce stand

    Directory of Open Access Journals (Sweden)

    Eva Dařenová

    2011-01-01

    Full Text Available Respiration of stems contributes approximately 8 to 13 % to the total respiration of forest ecosystem, which is not negligible, and it has to be included in carbon flux estimates. The aim of this study was to determine dynamics of stem CO2 efflux during the growing season in Norway spruce stand and factors affecting this efflux. Continuous measurements of stem CO2 efflux were carried out by an automated system during the growing season in 2006–2009. Further measured characteristics were stem temperature, stem increment and precipitations. Stem CO2 efflux was in tight relationship with changes in temperature with the mean coefficient of determination of 0.76. This infers that temperature was the main factor driving changes in CO2 efflux during the season. To eliminate effect of temperature and determine other factors influencing stem CO2 efflux, CO2 efflux was normalized for temperature of 10 °C (R10. Basic seasonal course of R10 followed the pattern of stem growth rate with its maxima in June and July. The other factor effect, which was possible to determine, was presence of rainfall. Rainfall strong enough caused mostly increase in R10. This effect was the most significant when the R10 course had a decreasing trend in the second part of the growing season.

  5. Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean

    KAUST Repository

    Holding, J. M.

    2015-08-31

    The Arctic Ocean is warming at two to three times the global rate1 and is perceived to be a bellwether for ocean acidification2, 3. Increased CO2 concentrations are expected to have a fertilization effect on marine autotrophs4, and higher temperatures should lead to increased rates of planktonic primary production5. Yet, simultaneous assessment of warming and increased CO2 on primary production in the Arctic has not been conducted. Here we test the expectation that CO2-enhanced gross primary production (GPP) may be temperature dependent, using data from several oceanographic cruises and experiments from both spring and summer in the European sector of the Arctic Ocean. Results confirm that CO2 enhances GPP (by a factor of up to ten) over a range of 145–2,099 μatm; however, the greatest effects are observed only at lower temperatures and are constrained by nutrient and light availability to the spring period. The temperature dependence of CO2-enhanced primary production has significant implications for metabolic balance in a warmer, CO2-enriched Arctic Ocean in the future. In particular, it indicates that a twofold increase in primary production during the spring is likely in the Arctic.

  6. 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

  7. 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.

  8. Exploring the effect of fluorinated anions on the CO2/N2 separation of supported ionic liquid membranes.

    Science.gov (United States)

    Gouveia, Andreia S L; Tomé, Liliana C; Lozinskaya, Elena I; Shaplov, Alexander S; Vygodskii, Yakov S; Marrucho, Isabel M

    2017-11-01

    The CO2 and N2 permeation properties of ionic liquids (ILs) based on the 1-ethyl-3-methylimidazolium cation ([C2mim](+)) and different fluorinated anions, namely 2,2,2-trifluoromethylsulfonyl-N-cyanoamide ([TFSAM](-)), bis(fluorosulfonyl) imide ([FSI](-)), nonafluorobutanesulfonate ([C4F9SO3](-)), tris(pentafluoroethyl)trifluorophosphate ([FAP](-)), and bis(pentafluoroethylsulfonyl)imide ([BETI](-)) anions, were measured using supported ionic liquid membranes (SILMs). The results show that pure ILs containing [TFSAM](-) and [FSI](-) anions present the highest CO2 permeabilities, 753 and 843 Barrer, as well as the greatest CO2/N2 permselectivities of 43.9 and 46.1, respectively, with CO2/N2 separation performances on top of or above the Robeson 2008 upper bound. The re-design of the [TFSAM](-) anion by structural unfolding was investigated through the use of IL mixtures. The gas transport and CO2/N2 separation properties through a pure [C2mim][TFSAM] SILM are compared to those of two different binary IL mixtures containing fluorinated and cyano-functionalized groups in the anions. Although the use of IL mixtures is a promising strategy to tailor gas permeation through SILMs, the pure [C2mim][TFSAM] SILM displays higher CO2 permeability, diffusivity and solubility than the selected IL mixtures. Nevertheless, both the prepared mixtures present CO2 separation performances that are on top of or above the Robeson plot.

  9. 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.

  10. Low Temperature Thermodynamic Equilibrium of CO2 Dimer Anion Species in Cryogenic Argon and Krypton Matrices

    Science.gov (United States)

    Goodrich, Michael E.; Moore, David T.

    2016-06-01

    The separated CO2 dimer anion, (CO2)(CO2-), is observed by FTIR spectroscopy in matrix isolation experiments at 1652 cm-1 upon deposition of high energy argon ions into an argon matrix doped with 0.5% CO2. It has previously been reported by Andrews that upon annealing the matrix to 25K, the separated species converts to an oxalate-like C2O4- species which appears at 1856 cm-1.a We have observed that subsequently holding the matrix at 10K caused the C2O4- species to fully convert back to (CO2)(CO2-). Upon further investigation, we determined that the two species reversibly interconvert between 19K and 23K, suggesting the species are in thermodynamic equilibrium. The associated van't Hoff plot has a linear trend and indicates an endothermic reaction driven by a large increase in entropy. An analogous experiment in a krypton matrix was performed, and the equilibrium was found to occur between 26K and 31K. Interestingly, analysis revealed the reaction in krypton is more endothermic, but has nearly the same entropy value as was observed in the argon experiment. aZhou, M.; Andrews, L.; J. Chem. Phys. 110, 2414 (1999).

  11. An energy balance perspective on regional CO2-induced temperature changes in CMIP5 models

    OpenAIRE

    Räisänen, Jouni

    2017-01-01

    An energy balance decomposition of temperature changes is conducted for idealized transient CO2-only simulations in the fifth phase of the Coupled Model Intercomparison Project. The multimodel global mean warming is dominated by enhanced clear-sky greenhouse effect due to increased CO2 and water vapour, but other components of the energy balance substantially modify the geographical and seasonal patterns of the change. Changes in the net surface energy flux are important over the oceans, bein...

  12. Synergism between elevated pCO2 and temperature on the Antarctic sea ice diatom Nitzschia lecointei

    Directory of Open Access Journals (Sweden)

    A. Torstensson

    2013-10-01

    Full Text Available Polar oceans are particularly susceptible to ocean acidification and warming. Diatoms play a significant role in sea ice biogeochemistry and provide an important food source to grazers in ice-covered oceans, especially during early spring. However, the ecophysiology of ice-living organisms has received little attention in terms of ocean acidification. In this study, the synergism between temperature and partial pressure of CO2 (pCO2 was investigated in relationship to the optimal growth temperature of the Antarctic sea ice diatom Nitzschia lecointei. Diatoms were kept in cultures at controlled levels of pCO2 (∼390 and ∼960 μatm and temperature (−1.8 and 2.5 °C for 14 days. Synergism between temperature and pCO2 was detected in growth rate and acyl lipid fatty acid (FA content. Optimal growth rate was observed around 5 °C in a separate experiment. Carbon enrichment only promoted (6% growth rate closer to the optimal growth, but not at the control temperature (−1.8 °C. At −1.8 °C and at ∼960 μatm pCO2, the total FA content was reduced relative to the ∼390 μatm treatment, although no difference between pCO2 treatments was observed at 2.5 °C. A large proportion (97% of the total FAs comprised on average of polyunsaturated fatty acids (PUFA at −1.8 °C. Cellular PUFA content was reduced at ∼960 relative to ∼390 μatm pCO2. Effects of carbon enrichment may be different depending on ocean warming scenario or season, e.g. reduced cellular FA content in response to elevated CO2 at low temperatures only, reflected as reduced food quality for higher trophic levels. Synergy between warming and acidification may be particularly important in polar areas since a narrow thermal window generally limits cold-water organisms.

  13. Interactive effect of temperature and CO2 increase in Arctic phytoplankton

    Directory of Open Access Journals (Sweden)

    Alexandra eCoello-Camba

    2014-10-01

    Full Text Available An experiment was performed in order to analyze the effects of the increase in water temperature and CO2 partial pressure expected for the end of this century in a present phytoplankton community inhabiting the Arctic Ocean. We analyzed both factors acting independently and together, to test possible interactions between them. The arctic planktonic community was incubated under 6 different treatments combining three experimental temperatures (1 ºC, 6 ºC and 10 ºC with two different CO2 levels of 380 ppm or 1000 ppm, at the UNIS installations in Longyearbyen (Svalbard, in summer 2010. Under warmer temperatures, a decrease in chlorophyll a concentration, biovolume and primary production was found, together with a shift in community structure towards a dominance of smaller cells (nano-sized. Effects of increased pCO2 were more modest, and although interactions were weak, our results suggest antagonistic interactive effects amongst increased temperature and CO2 levels, as elevated CO2 compensated partially the decrease in phytoplankton biomass induced by temperature in some groups. Interactions between the two stressors were generally weak, but elevated CO2 was observed to lead to a stepper decline in primary production with warming. Our results also suggest that future increases in water temperature and pCO2 would lead to a decrease in the community chl a concentration and biomass in the Arctic phytoplankton communities examined, leading to communities dominated by smaller nano-phytoplankton groups, with important consequences for the flow of carbon and food web dynamics.

  14. Sensitivity of grapevine phenology to water availability, temperature and CO2 concentration

    Directory of Open Access Journals (Sweden)

    Johann Martínez-Lüscher

    2016-07-01

    Full Text Available In recent decades, mean global temperatures have increased in parallel with a sharp rise in atmospheric carbon dioxide (CO2 levels, with apparent implications for precipitation patterns. The aim of the present work is to assess the sensitivity of different phenological stages of grapevine to temperature and to study the influence of other factors related to climate change (water availability and CO2 concentration on this relationship. Grapevine phenological records from 9 plantings between 42.75°N and 46.03°N consisting of dates for budburst, flowering and fruit maturity were used. In addition, we used phenological data collected from two years of experiments with grapevine fruit-bearing cuttings with two grapevine varieties under two levels of water availability, two temperature regimes and two levels of CO2. Dormancy breaking and flowering were strongly dependent on spring temperature, while neither variation in temperature during the chilling period nor precipitation significantly affected budburst date. The time needed to reach fruit maturity diminished with increasing temperature and decreasing precipitation. Experiments under semi-controlled conditions revealed great sensitivity of berry development to both temperature and CO2. Water availability had significant interactions with both temperature and CO2; however, in general, water deficit delayed maturity when combined with other factors. Sensitivities to temperature and CO2 varied widely, but higher sensitivities appeared in the coolest year, particularly for the late ripening variety, ‘White Tempranillo’. The knowledge gained in whole plant physiology and multi stress approaches is crucial to predict the effects of climate change and to design mitigation and adaptation strategies allowing viticulture to cope with climate change.

  15. Elevated temperature and CO(2) concentration effects on xylem anatomy of Scots pine.

    Science.gov (United States)

    Kilpeläinen, Antti; Gerendiain, Ane Zubizarreta; Luostarinen, Katri; Peltola, Heli; Kellomäki, Seppo

    2007-09-01

    We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross

  16. 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...

  17. Projected near-future levels of temperature and pCO2 reduce coral fertilization success.

    Directory of Open Access Journals (Sweden)

    Rebecca Albright

    Full Text Available Increases in atmospheric carbon dioxide (pCO2 are projected to contribute to a 1.1-6.4°C rise in global average surface temperatures and a 0.14-0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C and pCO2 (+400 µatm projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2 and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential.

  18. 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.

  19. Novel silica membranes for high temperature gas separations

    KAUST Repository

    Bighane, Neha

    2011-04-01

    This article describes fabrication of novel silica membranes derived via controlled oxidative thermolysis of polydimethylsiloxane and their gas separation performance. The optimized protocol for fabrication of the silica membranes is described and pure gas separation performance in the temperature range 35-80°C is presented. It is observed that the membranes exhibit activated transport for small gas penetrants such as He, H 2 and CO 2. The membranes can withstand temperatures up to 350°C in air and may ultimately find use in H 2/CO 2 separations to improve efficiency in the water-gas shift reactor process. © 2011 Elsevier B.V.

  20. Light availability and temperature, not increased CO2, will structure future meadows of Posidonia oceanica

    KAUST Repository

    Hendriks, Iris E.

    2017-02-15

    We evaluated the photosynthetic performance of Posidonia oceanica during short-term laboratory exposures to ambient and elevated temperatures (24–25°C and 29–30°C) warming and pCO2 (380, 750 and 1000ppm pCO2) under normal and low light conditions (200 and 40μmol photons m−2s−1 respectively). Plant growth was measured at the low light regime and showed a negative response to warming. Light was a critical factor for photosynthetic performance, although we found no evidence of compensation of photosynthetic quantum efficiency in high light. Relative Electron Rate Transport (rETRmax) was higher in plants incubated in high light, but not affected by pCO2 or temperature. The saturation irradiance (Ik) was negatively affected by temperature. We conclude that elevated CO2 does not enhance photosynthetic activity and growth, in the short term for P. oceanica, while temperature has a direct negative effect on growth. Low light availability also negatively affected photosynthetic performance during the short experimental period examined here. Therefore increasing concentrations of CO2 may not compensate for predicted future conditions of warmer water and higher turbidity for seagrass meadows.

  1. Study on effect of temperature and humidity on the CO2 concentration measurement

    Science.gov (United States)

    Liu, YuLiang; Ni, Xiang; Wu, YuanXi; Zhang, Wei

    2017-08-01

    In the application of non dispersive infrared (NDIR) carbon dioxide (CO2) concentration measurement, we need avoid the interference factors (such as temperature, pressure, gas, fluctuation of the light source and dust pollution etc.). In the past experiments only single factor, such as temperature, is often emphasized to the influence on the measurement results, without considering the effect of multiple factors. In order to study the change of gas concentration with measurement parameters, we constructs a CO2 detecting device with a BM530 gas detecting module, TMD10 temperature and humidity sensor. The experimental results show that: there is a correlation between the two interference factors: temperature and humidity. With the decreasing temperature, gas concentration measurement value decreases too. In developing process of instruments, we can make correction of the concentration- temperature instead of that of the measurement results under different temperature and humidity conditions.

  2. Impact of drought and increasing temperatures on soil CO2 emissions in a Mediterranean shrubland (gariga)

    DEFF Research Database (Denmark)

    de Dato, Giovanbattista Domenico; De Angelis, Paolo; Sirca, Costantino

    2010-01-01

    In arid and semiarid shrubland ecosystems of the Mediterranean basin, soil moisture is a key factor controlling biogeochemical cycles and the release of CO2 via soil respiration. This is influenced by increasing temperatures. We manipulated the microclimate in a Mediterranean shrubland to increase......) by covering the vegetation during the night (Warming treatment) and during rain events (Drought treatment). Soil CO2 effluxes were monitored in the treatments and compared to a control over a 3-year period. Along with soil respiration measurements, we recorded soil temperature at 5 cm depth by a soil...... on only three of 10 occasions during 2004. The variation of soil respiration with temperature and soil water content did not differ significantly among the treatments, but was affected by the season. The annual CO2 emissions were not significantly affected by the treatments. In the semi-arid Mediterranean...

  3. Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation.

    Science.gov (United States)

    Frahm, Ken S; Andersen, Ole K; Arendt-Nielsen, Lars; Mørch, Carsten D

    2010-11-08

    CO2 lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers. In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO2 laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p 0.90, p CO2 laser stimulation intensity, temperature levels and nociceptor activation.

  4. 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....

  5. Sol-gel processed magnesium-doped silica membranes with improved H2/CO2 separation

    NARCIS (Netherlands)

    Karakiliç, Pelin; Huiskes, Cindy; Luiten-Olieman, Maria W.J.; Nijmeijer, Arian; Winnubst, A.J.A.

    2017-01-01

    Magnesium-doped silica membranes were synthesized and a large increase in H2/CO2 permselectivity is achieved as compared to undoped silica membranes. Three magnesium concentrations were studied, namely 10, 15 and 20 mol%, in order to find the optimal Mg-concentration for the highest H2/CO2

  6. Integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops

    DEFF Research Database (Denmark)

    Aaslyng, J.M.; Körner, O.; Andreassen, A.U.

    2005-01-01

    A leaf photosynthesis model is suggested for integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops. Three different approaches for the optimization are presented. First, results from greenhouse experiments with model based optimization are presented....... Second, a model-based analysis of a commercial grower's production possibility is shown. Third, results from a simulation of the effect of a new lighting strategy are demonstrated. The results demonstrate that it is possible to optimize plant production by using a model-based integrated optimization...... of temperature, CO2, and light in the greenhouse...

  7. Temperature Dependence of Solar Light Assisted CO2 Reduction on Ni Based Photocatalyst

    OpenAIRE

    Albero Sancho, Josep; García Gómez, Hermenegildo; Corma Canós, Avelino

    2016-01-01

    Methanation of CO2 by H-2 can be in the future an important reaction to store the surplus of renewable electricity during production peaks. The catalytic thermal CO2 methanation (the Sabatier reaction) can be carried out at temperatures above 250 degrees C using Ni supported on silica-alumina (Ni/SiO2-Al2O3). Recently it has been observed that this exothermic reaction can be promoted by solar light irradiation of Ni/SiO2-Al2O3 at initial near ambient temperatures. In the present work we provi...

  8. Scheduling the blended solution as industrial CO2 absorber in separation process by back-propagation artificial neural networks.

    Science.gov (United States)

    Abdollahi, Yadollah; Sairi, Nor Asrina; Said, Suhana Binti Mohd; Abouzari-lotf, Ebrahim; Zakaria, Azmi; Sabri, Mohd Faizul Bin Mohd; Islam, Aminul; Alias, Yatimah

    2015-11-05

    It is believe that 80% industrial of carbon dioxide can be controlled by separation and storage technologies which use the blended ionic liquids absorber. Among the blended absorbers, the mixture of water, N-methyldiethanolamine (MDEA) and guanidinium trifluoromethane sulfonate (gua) has presented the superior stripping qualities. However, the blended solution has illustrated high viscosity that affects the cost of separation process. In this work, the blended fabrication was scheduled with is the process arranging, controlling and optimizing. Therefore, the blend's components and operating temperature were modeled and optimized as input effective variables to minimize its viscosity as the final output by using back-propagation artificial neural network (ANN). The modeling was carried out by four mathematical algorithms with individual experimental design to obtain the optimum topology using root mean squared error (RMSE), R-squared (R(2)) and absolute average deviation (AAD). As a result, the final model (QP-4-8-1) with minimum RMSE and AAD as well as the highest R(2) was selected to navigate the fabrication of the blended solution. Therefore, the model was applied to obtain the optimum initial level of the input variables which were included temperature 303-323 K, x[gua], 0-0.033, x[MDAE], 0.3-0.4, and x[H2O], 0.7-1.0. Moreover, the model has obtained the relative importance ordered of the variables which included x[gua]>temperature>x[MDEA]>x[H2O]. Therefore, none of the variables was negligible in the fabrication. Furthermore, the model predicted the optimum points of the variables to minimize the viscosity which was validated by further experiments. The validated results confirmed the model schedulability. Accordingly, ANN succeeds to model the initial components of the blended solutions as absorber of CO2 capture in separation technologies that is able to industries scale up. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Performance Estimation of Supercritical Co2 Micro Modular Reactor (MMR) for Varying Cooling Air Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoonhan; Kim, Seong Gu; Cho, Seong Kuk; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-05-15

    A Small Modular Reactor (SMR) receives interests for the various application such as electricity co-generation, small-scale power generation, seawater desalination, district heating and propulsion. As a part of SMR development, supercritical CO2 Micro Modular Reactor (MMR) of 36.2MWth in power is under development by the KAIST research team. To enhance the mobility, the entire system including the power conversion system is designed for the full modularization. Based on the preliminary design, the thermal efficiency is 31.5% when CO2 is sufficiently cooled to the design temperature. A supercritical CO2 MMR is designed to supply electricity to the remote regions. The ambient temperature of the area can influence the compressor inlet temperature as the reactor is cooled with the atmospheric air. To estimate the S-CO2 cycle performance for various environmental conditions, A quasi-static analysis code is developed. For the off design performance of S-CO2 turbomachineries, the experimental result of Sandia National Lab (SNL) is utilized.

  10. Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

    DEFF Research Database (Denmark)

    Frahm, Ken Steffen; Andersen, Ole K.; Arendt-Nielsen, Lars

    2010-01-01

    Background: CO(2) lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial...... to deeper skin layers. Methods: In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO(2) laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were...... dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO(2) laser stimulation intensity, temperature levels and nociceptor activation....

  11. Pilot-scale multistage membrane process for the separation of CO2 from LNG-fired flue gas

    KAUST Repository

    Choi, Seung Hak

    2013-06-01

    In this study, a multistage pilot-scale membrane plant was constructed and operated for the separation of CO2 from Liquefied Natural Gas (LNG)-fired boiler flue gas of 1000 Nm3/day. The target purity and recovery of CO2 were 99 vol.% and 90%, respectively. For this purpose, asymmetric polyethersulfone (PES) hollow fibers membranes has been developed in our previous work and has evaluated the effects of operating pressure and feed concentration of CO2 on separation performance. The operating and permeation data obtained were also analyzed in relation with the numerical simulation data using countercurrent flow model. Based on these results, in this study, four-staged membrane process including dehumidification process has been designed, installed, and operated to demonstrate the feasibility of multistage membrane systems for removing CO2 from flue gases. The operation results using this plant were compared to the numerical simulation results on multistage membrane process. The experimental results matched well with the numerical simulation data. The concentration and the recovery of CO2 in the permeate stream of final stage were ranged from 95-99 vol.% and 70-95%, respectively, depending on the operating conditions. This study demonstrated the applicability of the membrane-based pilot plant for CO2 recovery from flue gas. © 2013 Elsevier B.V. All rights reserved.

  12. A generic analysis of energy use and solvent selection for CO2 separation from post-combustion flue gases

    Science.gov (United States)

    Lu, Y.; Chen, S.; Rostam-Abadi, M.

    2008-01-01

    A thermodynamic calculation was performed to determine the theoretical minimum energy used to separate CO2 from a coal combustion flue gas in a typical adsorption-desorption system. Under ideal conditions, the minimum energy required to separate CO2 from post-combustion flue gas and produce pure CO2 at 1 atmospheric pressure was only about 1183 kJ/kg CO2. This amount could double with the addition of the driving forces of mass and heat transfer and the adverse impacts of absorption heat release on adsorption capacity. Thermodynamic analyses were also performed for the aqueous amine-based absorption process. Two CO2 reaction mechanisms, the carbamate formation reaction with primary/secondary amines and the CO2 hydration reaction with tertiary amines, were included in the absorption reaction. The reaction heat, sensible heat, and stripping heat were all important to the total heat requirement. The heat use of an ideal tertiary amine amounted to 2786 kJ/kg, compared to 3211 kJ/kg for an ideal primary amine. The heat usage of an ideal amine was about 20% lower than that of commercially available amines. Optimizing the absorption process configuration could further reduce energy use. This is an abstract of a paper presented at the 2008 AIChE Spring National Meeting (New Orleans, LA 4/6-10/2008).

  13. Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage

    Energy Technology Data Exchange (ETDEWEB)

    Mahesh Iyer; Shwetha Ramkumar; Liang-Shih Fan

    2006-09-30

    Enhancement in the production of high purity hydrogen from fuel gas, obtained from coal gasification, is limited by thermodynamics of the Water Gas Shift Reaction. However, this constraint can be overcome by concurrent water-gas shift (WGS) and carbonation reactions to enhance H{sub 2} production by incessantly driving the equilibrium-limited WGS reaction forward and in-situ removing the CO2 product from the gas mixture. The spent sorbent is then regenerated by calcining it to produce a pure stream of CO{sub 2} and CaO which can be reused. However while performing the cyclic carbonation and calcination it was observed that the CO{sub 2} released during the in-situ calcination causes the deactivation of the iron oxide WGS catalyst. Detailed understanding of the iron oxide phase diagram helped in developing a catalyst pretreatment procedure using a H{sub 2}/H{sub 2}O system to convert the deactivated catalyst back to its active magnetite (Fe{sub 3}O{sub 4}) form. The water gas shift reaction was studied at different temperatures, different steam to carbon monoxide ratios (S/C) 3:1, 2:1, 1:1 and different total pressures ranging from 0-300 psig. The combined water gas shift and carbonation reaction was investigated at temperatures ranging from 600-700C, S/C ratio of 3:1 to 1:1 and at different pressures of 0-300 psig and the calcium looping process was found to produce high purity hydrogen with in-situ CO{sub 2} capture.

  14. Eroding vs. Depositional Sites: Varying Sensitivity of CO2 Emissions to Temperature

    Science.gov (United States)

    Wang, Rui; Du, Lanlan; Hu, Yaxian; Guo, Shengli

    2017-04-01

    Erosion induced lateral transport of soil particles not only geographically redistributes soil organic carbon (SOC) across landscapes, but also relocate them to different microclimate conditions, potentially experiencing distinctive biochemical processes. To fully understand the impacts of soil erosion to atmospheric CO2, it requires to identify individual contributions from different geographic positions. Apart from differentiated CO2 emission potentials on eroding and depositional sites, previous reports have also recognized that the extents of SOC mineralization during transport can shift erosion induced effects from net sink to net source. However, most of the research or modeling has been carried out under current climate conditions. With more variable temperature patterns in the future, it is essential to understand the varying sensitivity of CO2 emissions to temperature changes on eroding and depositional sites. To systematically investigate the potential effects of temperature changes to erosion-induced CO2 emissions, four erosion plots were set up on the Chinese Loess Plateau. Each of the four plots had an eroding slope (1 m * 5 m, inclined at 20) filled with dark loess soil, and a depositional site (water tank by 1 m * 1 m) at the lower end. Soil temperature, soil moisture and CO2 emissions from surface at upper, middle and lower positions on each plot were continuously monitored from July 2014 to September 2015 under natural precipitation. Our results show that: 1) The depositional sites had up to 31% greater CO2 emission rates than the eroding slopes (1.38 vs. 1.05 µmol m-2 s-1 on average). This was probably because the mineralization of the enriched SOC at the depositional sites (6% greater than the original soil of 6.83 g kg-1 ) was enhanced by the more favorable soil moisture contents (0.25 m3 m-3 vs. 0.21 m3 m-3 at the eroding slopes). 2) The CO2 emissions from the depositional sites were much more sensitive to seasonal temperature changes

  15. CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating.

    Science.gov (United States)

    Shivananju, B N; Yamdagni, S; Fazuldeen, R; Sarin Kumar, A K; Hegde, G M; Varma, M M; Asokan, S

    2013-06-01

    The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.

  16. New insights on CO2-methane separation using LTA zeolites with different Si/Al ratios and a first comparison with MOFs.

    Science.gov (United States)

    Palomino, Miguel; Corma, Avelino; Rey, Fernando; Valencia, Susana

    2010-02-02

    LTA zeolites can be synthesized with tailored adsorption properties by controlling the Al content in the framework. In this work, we have demonstrated that it is possible to adjust the polarity of the zeolitic adsorbent to optimize its thermodynamic adsorption properties for the energetically relevant CO(2)/CH(4) separation process. The thermodynamic study has been made from the corresponding adsorption isotherms of the pure gases carried out at different pressures and temperatures, as well as breakthrough separation experiments of CO(2)/CH(4) mixtures and the results were compared to those reported on MOFs. The separation values obtained allow us to conclude that LTA zeolites offer unique possibilities for CH(4) upgrading from natural gas.

  17. Effects of temperature and CO2 pressure on the emission of N,N ...

    Indian Academy of Sciences (India)

    Effects of temperature and CO2 pressure on the emission of. N,N -dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important? KIZHMURI P DIVYAa,b, MICHAEL J BERTOCCHIa and RICHARD G WEISSa,∗. aDepartment of Chemistry, Georgetown University, Washington ...

  18. Rational design of temperature swing adsorption cycles for post-combustion CO2 capture

    NARCIS (Netherlands)

    Joss, Lisa; Gazzani, Matteo; Mazzotti, Marco

    2017-01-01

    The design of temperature swing adsorption (TSA) cycles aimed at recovering the heavy product at high purity is investigated by model-based design and applied to the capture of CO2 from flue gases. This model based design strategy and an extensive parametric analysis enables gaining an understanding

  19. Effects of Temperature Rise and Increase in CO2 Concentration on Simulated Wheat Yields in Europe

    NARCIS (Netherlands)

    Nonhebel, Sanderine

    1996-01-01

    A crop-growth-simulation model based on SUCROS87 was used to study effects of temperature rise and increase of atmospheric CO2 concentration on wheat yields in several regions in Europe. The model simulated potential and water-limited crop production (growth with ample supply of nutrients and in the

  20. Glycine uptake in heath plants and soil microbes responds to elevated temperature, CO2 and drought

    DEFF Research Database (Denmark)

    Andresen, Luise C.; Michelsen, Anders; Jonasson, Sven

    2009-01-01

    Temperate terrestrial ecosystems are currently exposed to climatic and air quality changes with increased atmospheric CO2, increased temperature and prolonged droughts. The responses of natural ecosystems to these changes are focus for research, due to the potential feedbacks to the climate. We...

  1. Nitrogen transformations in a forested catchment in southern Norway subjected to elevated temperature and CO2

    NARCIS (Netherlands)

    Verburg, P.S.J.; Breemen, van N.

    2000-01-01

    Model predictions on the response of soil processes to global warming are mostly inferred from small-scale laboratory studies. In this study, a forested catchment in southern Norway was enclosed by a greenhouse and experimentally manipulated by increasing CO2 ( 200ll-1 above ambient) and temperature

  2. Optimisation of CO2 and Temperature in Terms of Crop Growth and Energy Use

    NARCIS (Netherlands)

    Dieleman, J.A.; Meinen, E.; Marcelis, L.F.M.; Zwart, de H.F.; Henten, van E.J.

    2005-01-01

    In current greenhouse climate control, temperature set points follow a pre-set trajectory based on absolute or solar time parameters, adapted only to instantaneous and daily radiation. CO2 is supplied during a well defined period of the day until a maximum concentration is reached. However, the rate

  3. Temperature response of biological materials to pulsed non-ablative CO2 laser irradiation

    NARCIS (Netherlands)

    Brugmans, M. J.; Kemper, J.; Gijsbers, G. H.; van der Meulen, F. W.; van Gemert, M. J.

    1991-01-01

    This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an

  4. Sensitivity to low-temperature events: Implications for CO2 dynamics in subtropical coastal ecosystems

    Science.gov (United States)

    Sparkle L. Malone; Jordan Barr; Jose D. Fuentes; Steven F. Oberbauer; Christina L. Staudhammer; Evelyn E. Gaiser; Gregory Starr

    2016-01-01

    We analyzed the ecosystem effects of low-temperature events (<5 °C) over 4 years (2009-2012) in subtropical short and long hydroperiod freshwater marsh and mangrove forests within Everglades National Park. To evaluate changes in ecosystem productivity, we measured temporal patterns of CO2 and the normalized difference vegetation index over the study period. Both...

  5. A statistical analysis of three ensembles of crop model responses to temperature and CO2 concentration

    Science.gov (United States)

    Ensembles of process-based crop models are now commonly used to simulate crop growth and development for climate scenarios of temperature and/or precipitation changes corresponding to different projections of atmospheric CO2 concentrations. This approach generates large datasets with thousands of de...

  6. Numerical simulation of CO2 separation from gas mixtures in membrane modules: Effect of chemical absorbent

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Reza Razavi

    2016-01-01

    Full Text Available In this study, a mathematical model is proposed for prediction of CO2 absorption from N2/CO2 mixture by potassium threonate in a hollow-fiber membrane contactor (HFMC. CFD technique using numerical method of finite element was applied to solve the governing equations of model. Effect of different factors on CO2 absorption was analyzed and for investigation of absorbent type effect, functioning of potassium threonate was compared with diethanolamine (DEA. Axial and radial diffusion can be described with the two dimensional model established in this work. The obtained simulation results were compared with the reported experimental data to ensure accuracy of the model predictions. Comparison of model results with experimental data revealed that the developed model can well predict CO2 capture by potassium threonate in HFMCs. Increment of absorbent flow rate and concentration eventuate in enhancement of CO2 absorption. On the other hand, capture of CO2 will be reduced with increment of gas flow rate. According to the model results, potassium threonate can be considered as a more efficient absorbent as compared with DEA.

  7. Modified ZIF-8 mixed matrix membrane for CO2/CH4 separation

    Science.gov (United States)

    Nordin, Nik Abdul Hadi Md; Ismail, Ahmad Fauzi; Misdan, Nurasyikin; Nazri, Noor Aina Mohd

    2017-10-01

    Tunability of metal-organic frameworks (MOFs) properties enables them to be tailored for specific applications. In this study, zeolitic imidazole framework 8 (ZIF-8), sub-class of MOF, underwent pre-synthesis and post-synthesis modifications. The pre-synthesis modification using GO (ZIF-8/GO) shows slight decrease in textural properties, while the post-synthesis modification using amine solution (ZIF-8/NH2) resulted in superior BET surface area and pore volume. Mixed matrix membranes (MMMs) derived from polysulfone (PSf) and the modified ZIF-8s were then prepared via dry/wet phase inversion. The polymer chain flexibility of the resulted MMMs shows rigidification, where ZIF-8/NH2 as filler resulting higher rigidification compared to ZIF-8/GO. The MMMs were further subjected to pure CO2 and CH4 gas permeation experiments. The PSf/ZIF-8/NH2 shows superior CO2/CH4 selectivity (88% increased) while sacrificing CO2 permeance due to combination of severe polymer chain rigidification and the presence of CO2-philic group, amine. Whereas, the PSf/ZIF-8/GO possess 64% increase in CO2 permeance without notable changes in CO2/CH4 selectivity.

  8. Unstable maternal environment, separation anxiety, and heightened CO2 sensitivity induced by gene-by-environment interplay.

    Directory of Open Access Journals (Sweden)

    Francesca R D'Amato

    2011-04-01

    Full Text Available In man, many different events implying childhood separation from caregivers/unstable parental environment are associated with heightened risk for panic disorder in adulthood. Twin data show that the occurrence of such events in childhood contributes to explaining the covariation between separation anxiety disorder, panic, and the related psychobiological trait of CO(2 hypersensitivity. We hypothesized that early interference with infant-mother interaction could moderate the interspecific trait of response to CO(2 through genetic control of sensitivity to the environment.Having spent the first 24 hours after birth with their biological mother, outbred NMRI mice were cross-fostered to adoptive mothers for the following 4 post-natal days. They were successively compared to normally-reared individuals for: number of ultrasonic vocalizations during isolation, respiratory physiology responses to normal air (20%O(2, CO(2-enriched air (6% CO(2, hypoxic air (10%O(2, and avoidance of CO(2-enriched environments.Cross-fostered pups showed significantly more ultrasonic vocalizations, more pronounced hyperventilatory responses (larger tidal volume and minute volume increments to CO(2-enriched air and heightened aversion towards CO(2-enriched environments, than normally-reared individuals. Enhanced tidal volume increment response to 6%CO(2 was present at 16-20, and 75-90 postnatal days, implying the trait's stability. Quantitative genetic analyses of unrelated individuals, sibs and half-sibs, showed that the genetic variance for tidal volume increment during 6%CO(2 breathing was significantly higher (Bartlett χ = 8.3, p = 0.004 among the cross-fostered than the normally-reared individuals, yielding heritability of 0.37 and 0.21 respectively. These results support a stress-diathesis model whereby the genetic influences underlying the response to 6%CO(2 increase their contribution in the presence of an environmental adversity. Maternal grooming

  9. Inter-annual variability in fossil-fuel CO2 emissions due to temperature anomalies

    Science.gov (United States)

    Bréon, F.-M.; Boucher, O.; Brender, P.

    2017-07-01

    It is well known that short-term (i.e. interannual) variations in fossil-fuel CO2 emissions are closely related to the evolution of the national economies. Nevertheless, a fraction of the CO2 emissions are linked to domestic and business heating and cooling, which can be expected to be related to the meteorology, independently of the economy. Here, we analyse whether the signature of the inter-annual temperature anomalies is discernible in the time series of CO2 emissions at the country scale. Our analysis shows that, for many countries, there is a clear positive correlation between a heating-degree-person index and the component of the CO2 emissions that is not explained by the economy as quantified by the gross domestic product (GDP). Similarly, several countries show a positive correlation between a cooling-degree-person (CDP) index and CO2 emissions. The slope of the linear relationship for heating is on the order of 0.5-1 kg CO2 (degree-day-person)-1 but with significant country-to-country variations. A similar relationship for cooling shows even greater diversity. We further show that the inter-annual climate anomalies have a small but significant impact on the annual growth rate of CO2 emissions, both at the national and global scale. Such a meteorological effect was a significant contribution to the rather small and unexpected global emission growth rate in 2014 while its contribution to the near zero emission growth in 2015 was insignificant.

  10. Tailoring the free volume of all-aromatic polyimide membranes for CO2/CH4 gas separation

    NARCIS (Netherlands)

    Madzarevic, Z.

    2017-01-01

    Efficient and cost-effective technologies that will enable separation and capture of CO2 are needed. The development of high-performance all-aromatic poly(ether)imide (P(E)I) membranes is attractive as they offer a large degree of design freedom and they are cheap to operate. However, the molecular

  11. Fabrication of COF-MOF Composite Membranes and Their Highly Selective Separation of H2/CO2.

    Science.gov (United States)

    Fu, Jingru; Das, Saikat; Xing, Guolong; Ben, Teng; Valtchev, Valentin; Qiu, Shilun

    2016-06-22

    The search for new types of membrane materials has been of continuous interest in both academia and industry, given their importance in a plethora of applications, particularly for energy-efficient separation technology. In this contribution, we demonstrate for the first time that a metal-organic framework (MOF) can be grown on the covalent-organic framework (COF) membrane to fabricate COF-MOF composite membranes. The resultant COF-MOF composite membranes demonstrate higher separation selectivity of H2/CO2 gas mixtures than the individual COF and MOF membranes. A sound proof for the synergy between two porous materials is the fact that the COF-MOF composite membranes surpass the Robeson upper bound of polymer membranes for mixture separation of a H2/CO2 gas pair and are among the best gas separation MOF membranes reported thus far.

  12. Interactions Between Temperature and Intercellular CO2 Concentration in Controlling Leaf Isoprene Emission Rates

    Science.gov (United States)

    Monson, Russell K.; Neice, Amberly A.; Trahan, Nicole A.; Shiach, Ian; McCorkel, Joel T.; Moore, David J. P.

    2016-01-01

    Plant isoprene emissions have been linked to several reaction pathways involved in atmospheric photochemistry. Evidence exists from a limited set of past observations that isoprene emission rate (I(sub s)) decreases as a function of increasing atmospheric CO2 concentration, and that increased temperature suppresses the CO2 effect. We studied interactions between intercellular CO2 concentration (C(sub I)) and temperature as they affect I(sub s) in field-grown hybrid poplar trees in one of the warmest climates on earth - the Sonoran Desert of the southwestern United States. We observed an unexpected midsummer down regulation of I(sub s) despite the persistence of relatively high temperatures. High temperature suppression of the I(sub s):C(sub I) relation occurred at all times during the growing season, but sensitivity of I(sub s) to increased C(sub I) was greatest during the midsummer period when I(subs) was lowest. We interpret the seasonal down regulation of I(sub s) and increased sensitivity of I(sub s) to C(sub I) as being caused by weather changes associated with the onset of a regional monsoon system. Our observations on the temperature suppression of the I(sub s):C(sub I) relation are best explained by the existence of a small pool of chloroplastic inorganic phosphate, balanced by several large, connected metabolic fluxes, which together, determine the C(sub I) and temperature dependencies of phosphoenolpyruvate import into the chloroplast.

  13. Climate change and agroecosystems: the effect of elevated atmospheric CO2 and temperature on crop growth, development, and yield

    Directory of Open Access Journals (Sweden)

    Streck Nereu Augusto

    2005-01-01

    Full Text Available The amount of carbon dioxide (CO2 of the Earths atmosphere is increasing, which has the potential of increasing greenhouse effect and air temperature in the future. Plants respond to environment CO2 and temperature. Therefore, climate change may affect agriculture. The purpose of this paper was to review the literature about the impact of a possible increase in atmospheric CO2 concentration and temperature on crop growth, development, and yield. Increasing CO2 concentration increases crop yield once the substrate for photosynthesis and the gradient of CO2 concentration between atmosphere and leaf increase. C3 plants will benefit more than C4 plants at elevated CO2. However, if global warming will take place, an increase in temperature may offset the benefits of increasing CO2 on crop yield.

  14. 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.

  15. Low transition temperature mixtures as innovative and sustainable CO2 capture solvents.

    Science.gov (United States)

    Zubeir, Lawien F; Lacroix, Mark H M; Kroon, Maaike C

    2014-12-11

    The potential of three newly discovered low transition temperature mixtures (LTTMs) is explored as sustainable substituents for the traditional carbon dioxide (CO2) absorbents. LTTMs are mixtures of two solid compounds, a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), which form liquids upon mixing with melting points far below those of the individual compounds. In this work the HBD is lactic acid and the HBAs are tetramethylammonium chloride, tetraethylammonium chloride, and tetrabutylammonium chloride. These compounds were found to form LTTMs for the first time at molar ratios of HBD:HBA = 2:1. First, the LTTMs were characterized by determining the thermal operating window (e.g., decomposition temperature and glass transition temperature) and the physical properties (e.g., density and viscosity). Thereafter, the phase behavior of CO2 with the LTTMs has been measured using a gravimetric magnetic suspension balance operating in the static mode at 308 and 318 K and pressures up to 2 MPa. The CO2 solubility increased with increasing chain length, increasing pressure, and decreasing temperature. The Peng-Robinson equation of state was applied to correlate the phase equilibria. From the solubility data, thermodynamic parameters were determined (e.g., Henry's law coefficient and enthalpy of absorption). The heat of absorption was found to be similar to that in conventional physical solvents (-11.21 to -14.87 kJ·mol(-1)). Furthermore, the kinetics in terms of the diffusion coefficient of CO2 in all LTTMs were determined (10(-11)-10(-10) m(2)·s(-1)). Even though the CO2 solubilities in the studied LTTMs were found to be slightly lower than those in thoroughly studied conventional physical solvents, LTTMs are a promising new class of absorbents due to their low cost, their environmentally friendly character, and their easy tunability, allowing further optimization for carbon capture.

  16. Stepwise observation and quantification and mixed matrix membrane separation of CO2within a hydroxy-decorated porous host.

    Science.gov (United States)

    Morris, Christopher G; Jacques, Nicholas M; Godfrey, Harry G W; Mitra, Tamoghna; Fritsch, Detlev; Lu, Zhenzhong; Murray, Claire A; Potter, Jonathan; Cobb, Tom M; Yuan, Fajin; Tang, Chiu C; Yang, Sihai; Schröder, Martin

    2017-04-01

    The identification of preferred binding domains within a host structure provides important insights into the function of materials. State-of-the-art reports mostly focus on crystallographic studies of empty and single component guest-loaded host structures to determine the location of guests. However, measurements of material properties ( e.g. , adsorption and breakthrough of substrates) are usually performed for a wide range of pressure (guest coverage) and/or using multi-component gas mixtures. Here we report the development of a multifunctional gas dosing system for use in X-ray powder diffraction studies on Beamline I11 at Diamond Light Source. This facility is fully automated and enables in situ crystallographic studies of host structures under (i) unlimited target gas loadings and (ii) loading of multi-component gas mixtures. A proof-of-concept study was conducted on a hydroxyl-decorated porous material MFM-300(V III ) under (i) five different CO 2 pressures covering the isotherm range and (ii) the loading of equimolar mixtures of CO 2 /N 2 . The study has successfully captured the structural dynamics underpinning CO 2 uptake as a function of surface coverage. Moreover, MFM-300(V III ) was incorporated in a mixed matrix membrane (MMM) with PIM-1 in order to evaluate the CO 2 /N 2 separation potential of this material. Gas permeation measurements on the MMM show a great improvement over the bare PIM-1 polymer for CO 2 /N 2 separation based on the ideal selectivity.

  17. CO2 laser-grooved long period fiber grating temperature sensor system based on intensity modulation.

    Science.gov (United States)

    Wang, Yi-Ping; Wang, Dong Ning; Jin, Wei

    2006-11-01

    A long period fiber grating (LPFG) temperature sensor system based on intensity modulation is developed. The LPFG employed is fabricated by the use of a focused CO2 laser beam to carve periodic grooves on the fiber. The temperature measurement resolution of up to 0.1 degrees C has been obtained within the temperature range between 20 degrees C and 100 degrees C. The system uses a simple intensity measurement method and exhibits the advantages of convenient intensity measurement, double temperature sensitivity, high resolution, simple configuration, and low cost.

  18. Effective Approach for Increasing the Heteroatom Doping Levels of Porous Carbons for Superior CO2 Capture and Separation Performance.

    Science.gov (United States)

    Abdelmoaty, Yomna H; Tessema, Tsemre-Dingel; Norouzi, Nazgol; El-Kadri, Oussama M; Turner, Joseph B McGee; El-Kaderi, Hani M

    2017-10-18

    Development of efficient sorbents for carbon dioxide (CO2) capture from flue gas or its removal from natural gas and landfill gas is very important for environmental protection. A new series of heteroatom-doped porous carbon was synthesized directly from pyrazole/KOH by thermolysis. The resulting pyrazole-derived carbons (PYDCs) are highly doped with nitrogen (14.9-15.5 wt %) as a result of the high nitrogen-to-carbon ratio in pyrazole (43 wt %) and also have a high oxygen content (16.4-18.4 wt %). PYDCs have a high surface area (SABET = 1266-2013 m(2) g(-1)), high CO2 Qst (33.2-37.1 kJ mol(-1)), and a combination of mesoporous and microporous pores. PYDCs exhibit significantly high CO2 uptakes that reach 2.15 and 6.06 mmol g(-1) at 0.15 and 1 bar, respectively, at 298 K. At 273 K, the CO2 uptake improves to 3.7 and 8.59 mmol g(-1) at 0.15 and 1 bar, respectively. The reported porous carbons also show significantly high adsorption selectivity for CO2/N2 (128) and CO2/CH4 (13.4) according to ideal adsorbed solution theory calculations at 298 K. Gas breakthrough studies of CO2/N2 (10:90) at 298 K showed that PYDCs display excellent separation properties. The ability to tailor the physical properties of PYDCs as well as their chemical composition provides an effective strategy for designing efficient CO2 sorbents.

  19. 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.

  20. Dual-Pump Coherent Anti-Stokes Raman Scattering Temperature and CO2 Concentration Measurements

    Science.gov (United States)

    Lucht, Robert P.; Velur-Natarajan, Viswanathan; Carter, Campbell D.; Grinstead, Keith D., Jr.; Gord, James R.; Danehy, Paul M.; Fiechtner, G. J.; Farrow, Roger L.

    2003-01-01

    Measurements of temperature and CO2 concentration using dual-pump coherent anti-Stokes Raman scattering, (CARS) are described. The measurements were performed in laboratory flames,in a room-temperature gas cell, and on an engine test stand at the U.S. Air Force Research Laboratory, Wright-Patterson Air Force Base. A modeless dye laser, a single-mode Nd:YAG laser, and an unintensified back-illuminated charge-coupled device digital camera were used for these measurements. The CARS measurements were performed on a single-laser-shot basis. The standard deviations of the temperatures and CO2 mole fractions determined from single-shot dual-pump CARS spectra in steady laminar propane/air flames were approximately 2 and 10% of the mean values of approximately 2000 K and 0.10, respectively. The precision and accuracy of single-shot temperature measurements obtained from the nitrogen part of the dual-pump CARS system were investigated in detail in near-adiabatic hydrogen/air/CO2 flames. The precision of the CARS temperature measurements was found to be comparable to the best results reported in the literature for conventional two-laser, single-pump CARS. The application of dual-pump CARS for single-shot measurements in a swirl-stabilized combustor fueled with JP-8 was also demonstrated.

  1. Time evolution of vibrational temperatures in a CO2 glow discharge measured with infrared absorption spectroscopy

    Science.gov (United States)

    Klarenaar, B. L. M.; Engeln, R.; van den Bekerom, D. C. M.; van de Sanden, M. C. M.; Morillo-Candas, A. S.; Guaitella, O.

    2017-11-01

    Vibrational temperatures of CO2 are studied in a pulsed glow discharge by means of time-resolved in situ Fourier transform infrared spectroscopy, with a 10 μs temporal resolution. A method to analyze the infrared transmittance through vibrationally excited CO2 is presented and validated on a previously published CO2 spectrum, showing good agreement between fit and data. The discharge under study is pulsed with a typical duty cycle of 5–10 ms on–off, at 50 mA and 6.7 mbar. A rapid increase of the temperature of the asymmetric stretch vibration (T 3) is observed at the start of the pulse, reaching 1050 K, which is an elevation of 550 K above the rotational temperature ({T}{{rot}}) of 500 K. After the plasma pulse, the characteristic relaxation time of T 3 to {T}{{rot}} strongly depends on the rotational temperature. By adjusting the duty cycle, the rotational temperature directly after the discharge is varied from 530 to 860 K, resulting in relaxation times between 0.4 and 0.1 ms. Equivalently, as the gas heats up during the plasma pulse, the elevation of T 3 above {T}{{rot}} decreases strongly.

  2. Preparation of a Facilitated Transport Membrane Composed of Carboxymethyl Chitosan and Polyethylenimine for CO2/N2 Separation

    OpenAIRE

    Jiang-Nan Shen; Chang-Chao Yu; Gan-Ning Zeng; Bart van der Bruggen

    2013-01-01

    The miscibility of carboxymethyl chitosan/polyethylenimine (CMCS/PEI) blends was analyzed by FT-IR, TGA and SEM. Defect-free CMCS/PEI blend membranes were prepared with polysulfone (PSf) ultrafiltration membranes as support layer for the separation of CO2/N2 mixtures. The results demonstrate that the CMCS/PEI blend is miscible, due to the hydrogen bonding interaction between the two targeted polymers. For the blended membrane without water, the permeability of CO2 gas is 3.6 × 10−7 cm3 cm−2 s...

  3. Tailoring the free volume of all-aromatic polyimide membranes for CO2/CH4 gas separation

    OpenAIRE

    Madzarevic, Z.

    2017-01-01

    Efficient and cost-effective technologies that will enable separation and capture of CO2 are needed. The development of high-performance all-aromatic poly(ether)imide (P(E)I) membranes is attractive as they offer a large degree of design freedom and they are cheap to operate. However, the molecular design rules towards P(E)I membranes that exhibit high selectivity and high permeability with no or little CO2 plasticization are still largely unknown. The main objective of the research presented...

  4. Spring photosynthetic recovery of boreal Norway spruce under conditions of elevated [CO(2)] and air temperature.

    Science.gov (United States)

    Wallin, Göran; Hall, Marianne; Slaney, Michelle; Räntfors, Mats; Medhurst, Jane; Linder, Sune

    2013-11-01

    Accumulated carbon uptake, apparent quantum yield (AQY) and light-saturated net CO2 assimilation (Asat) were used to assess the responses of photosynthesis to environmental conditions during spring for three consecutive years. Whole-tree chambers were used to expose 40-year-old field-grown Norway spruce trees in northern Sweden to an elevated atmospheric CO2 concentration, [CO2], of 700 μmol CO2 mol(-1) (CE) and an air temperature (T) between 2.8 and 5.6 °C above ambient T (TE), during summer and winter. Net shoot CO2 exchange (Anet) was measured continuously on 1-year-old shoots and was used to calculate the accumulated carbon uptake and daily Asat and AQY. The accumulated carbon uptake, from 1 March to 30 June, was stimulated by 33, 44 and 61% when trees were exposed to CE, TE, and CE and TE combined, respectively. Air temperature strongly influenced the timing and extent of photosynthetic recovery expressed as AQY and Asat during the spring. Under elevated T (TE), the recovery of AQY and Asat commenced ∼10 days earlier and the activity of these parameters was significantly higher throughout the recovery period. In the absence of frost events, the photosynthetic recovery period was less than a week. However, frost events during spring slowed recovery so that full recovery could take up to 60 days to complete. Elevated [CO2] stimulated AQY and Asat on average by ∼10 and ∼50%, respectively, throughout the recovery period, but had minimal or no effect on the onset and length of the photosynthetic recovery period during the spring. However, AQY, Asat and Anet all recovered at significantly higher T (average +2.2 °C) in TE than in TA, possibly caused by acclimation or by shorter days and lower light levels during the early part of the recovery in TE compared with TA. The results suggest that predicted future climate changes will cause prominent stimulation of photosynthetic CO2 uptake in boreal Norway spruce forest during spring, mainly caused by elevated T

  5. GWAS of Barley Phenotypes Established Under Future Climate Conditions of Elevated Temperature, CO2, O3 and Elevated Temperature and CO2 Combined

    DEFF Research Database (Denmark)

    Ingvordsen, Cathrine Heinz; Backes, G.; Lyngkjær, M. F.

    2015-01-01

    Climate change is likely to decrease crop yields worldwide. Developing climate resilient cultivars is one way to combat this production scarcity, however, little is known of crop response to future climate conditions and in particular the variability within crops.In Scandinavia, barley is widely...... yield, grain protein concentration, grain protein harvested, number of grains, number of ears, aboveground vegetative biomass and harvest index. In addition, stability of the production was calculated over the applied treatments for the assessed parameters.In the climate scenario of elevated temperature...... and [CO2] the grain yield of barley decreased 29% and harvested grain protein declined 22%. Vast variation was identified among the individual barley accessions, which should be exploited by plant breeders in the development of climate resilient cultivars.A genome-wide association study (GWAS) of recorded...

  6. 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

  7. Sub- T g Cross-Linking of a Polyimide Membrane for Enhanced CO 2 Plasticization Resistance for Natural Gas Separation

    KAUST Repository

    Qiu, Wulin

    2011-08-09

    Decarboxylation-induced thermal cross-linking occurs at elevated temperatures (∼15 °C above glass transition temperature) for 6FDA-DAM:DABA polyimides, which can stabilize membranes against swelling and plasticization in aggressive feed streams. Despite this advantage, such a high temperature might result in collapse of substructure and transition layers in the asymmetric structure of a hollow fibers based on such a material. In this work, the thermal cross-linking of the 6FDA-DAM:DABA at temperatures much below the glass transition temperature (∼387 °C by DSC) was demonstrated. This sub-Tg cross-linking capability enables extension to asymmetric structures useful for large scale membranes. The resulting polymer membranes were characterized by swelling in known solvents for the un-cross-linked materials, TGA analysis, and permeation tests of aggressive gas feed stream at higher pressure. The annealing temperature and time clearly influence the degree of cross-linking of the membranes, and results in a slight difference in selectivity for membranes under various cross-linking conditions. Results indicate that the sub-Tg thermal cross-linking of 6FDA-DAM:DABA dense film membrane can be carried out completely even at a temperature as low as 330 °C. Permeabilities were tested for the polyimide membranes using both pure gases (He, O2, N2, CH4, CO2) and mixed gases (CO2/CH4). The selectivity of the cross-linked membrane can be maintained even under very aggressive CO2 operating conditions that are not possible without cross-linking. Moreover, the plasticization resistance was demonstrated up to 700 psia for pure CO 2 gas or 1000 psia for 50% CO2 mixed gas feeds. © 2011 American Chemical Society.

  8. Elevated CO2 reduced floret death in wheat under warmer average temperatures and terminal drought.

    Directory of Open Access Journals (Sweden)

    Eduardo eDias de Oliveira

    2015-11-01

    Full Text Available Elevated CO2 often increases grain yield in wheat by enhancing grain number per ear, which can result from an increase in the potential number of florets or a reduction in the death of developed florets. The hypotheses that elevated CO2 reduces floret death rather than increases floret development, and that grain size in a genotype with more grains per unit area is limited by the rate of grain filling, were tested in a pair of sister lines contrasting in tillering capacity (restricted- vs free-tillering. The hypotheses were tested under elevated CO2, combined with +3 C above ambient temperature and terminal drought, using specialized field tunnel houses. Elevated CO2 increased net leaf photosynthetic rates and likely the availability of carbon assimilates, which significantly reduced the rates of floret death and increased the potential number of grains at anthesis in both sister lines by an average of 42%. The restricted-tillering line had faster grain-filling rates than the free-tillering line because the free-tillering line had more grains to fill. Furthermore, grain-filling rates were faster under elevated CO2 and +3 C above ambient. Terminal drought reduced grain yield in both lines by 19%. Elevated CO2 alone increased the potential number of grains, but a trade-off in yield components limited grain yield in the free-tillering line. This emphasizes the need for breeding cultivars with a greater potential number of florets, since this was not affected by the predicted future climate variables.

  9. Development and characterization of polyethersulfone/TiO2 mixed matrix membranes for CO2/CH4 separation

    Science.gov (United States)

    Galaleldin, S.; Mannan, H. A.; Mukhtar, H.

    2017-12-01

    In this study, mixed matrix membranes comprised of polyethersulfone as the bulk polymer phase and titanium dioxide (TiO2) nanoparticles as the inorganic discontinuous phase were prepared for CO2/CH4 separation. Membranes were synthesized at filler loading of 0, 5, 10 and 15 wt % via dry phase inversion method. Morphology, chemical bonding and thermal characteristics of membranes were scrutinized utilizing different techniques, namely: Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform InfraRed (FTIR) spectra and Thermogravimetric analysis (TGA) respectively. Membranes gas separation performance was evaluated for CO2 and CH4 gases at 4 bar feed pressure. The highest separation performance was achieved by mixed matrix membrane (MMM) at 5 % loading of TiO2.

  10. [Effect of air temperature and rainfall on wetland ecosystem CO2 exchange in China].

    Science.gov (United States)

    Chu, Xiao-jing; Han, Guang-xuan

    2015-10-01

    Wetland can be a potential efficient sink to reduce global warming due to its higher primary productivity and lower carbon decomposition rate. While there has been a series progress on the influence mechanism of ecosystem CO2 exchange over China' s wetlands, a systematic metaanalysis of data still needs to be improved. We compiled data of ecosystem CO2 exchange of 21 typical wetland vegetation types in China from 29 papers and carried out an integrated analysis of air temperature and precipitation effects on net ecosystem CO2 exchange (NEE), ecosystem respiration (Reco), gross primary productivity (GPP), the response of NEE to PAR, and the response of Reco to temperature. The results showed that there were significant responses (Pair temperature and enhanced precipitation on the annual scale. On the growing season scale, air temperature accounted for 50% of the spatial variation of NEE, 36% of GPP and 19% of Reco, respectively. Both NEE (R2 = 33%) and GPP (R2 =25%) were correlated positively with precipitation (P0.05). Across different Chinese wetlands, both precipitation and temperature had no significant effect on apparent quantum yield (α) or ecosystem respiration in the daytime (Reco,day, P>0.05). The maximum photosynthesis rate (Amax) was remarkably correlated with precipitation (P air temperature. Besides, there was no significant correlation between basal respiration (Rref) and precipitation (P>0.05). Precipitation was negatively correlated with temperature sensitivity of Reco (Q10, P<0.05). Furthermore, temperature accounted for 35% and 46% of the variations in temperature sensitivity of Reco (Q10) and basal respiration (Rref P<0.05), respectively.

  11. Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mahesh Iyer; Himanshu Gupta; Danny Wong; Liang-Shih Fan

    2005-09-30

    Hydrogen production from coal gasification can be enhanced by driving the equilibrium limited Water Gas Shift reaction forward by incessantly removing the CO{sub 2} by-product via the carbonation of calcium oxide. This project aims at using the OSU patented high-reactivity mesoporous precipitated calcium carbonate sorbent for removing the CO{sub 2} product. Preliminary experiments demonstrate the show the superior performance of the PCC sorbent over other naturally occurring calcium sorbents. Gas composition analyses show the formation of 100% pure hydrogen. Novel calcination techniques could lead to smaller reactor footprint and single-stage reactors that can achieve maximum theoretical H{sub 2} production for multicyclic applications. Sub-atmospheric calcination studies reveal the effect of vacuum level, diluent gas flow rate, thermal properties of the diluent gas and the sorbent loading on the calcination kinetics which play an important role on the sorbent morphology. Steam, which can be easily separated from CO{sub 2}, is envisioned to be a potential diluent gas due to its enhanced thermal properties. Steam calcination studies at 700-850 C reveal improved sorbent morphology over regular nitrogen calcination. A mixture of 80% steam and 20% CO{sub 2} at ambient pressure was used to calcine the spent sorbent at 820 C thus lowering the calcination temperature. Regeneration of calcium sulfide to calcium carbonate was achieved by carbonating the calcium sulfide slurry by bubbling CO{sub 2} gas at room temperature.

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

    Directory of Open Access Journals (Sweden)

    Christina Hemme

    2017-03-01

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

  13. Effects of elevated temperature and CO2 concentration on photosynthesis of the alpine plants in Zoige Plateau, China

    Science.gov (United States)

    Zijuan, Zhou; Peixi, Su; Rui, Shi; Tingting, Xie

    2017-04-01

    Increasing temperature and carbon dioxide concentration are the important aspects of global climate change. Alpine ecosystem response to global change was more sensitive and rapid than other ecosystems. Increases in temperature and atmospheric CO2concentrations have strong impacts on plant physiology. Photosynthesis is the basis for plant growth and the decisive factor for the level of productivity, and also is a very sensitive physiological process to climate change. In this study, we examined the interactive effects of elevated temperature and atmospheric CO2 concentration on the light response of photosynthesis in two alpine plants Elymus nutans and Potentilla anserine, which were widely distributed in alpine meadow in the Zoige Plateau, China. We set up as follows: the control (Ta 20˚ C, CO2 380μmolṡmol-1), elevated temperature (Ta 25˚ C, CO2 380 μmolṡmol-1), elevated CO2 concentration (Ta 20˚ C, CO2 700μmolṡmol-1), elevated temperature and CO2 concentration (Ta 25˚ C, CO2 700μmolṡmol-1). The results showed that compared to P. anserine, E. nutans had a higher maximum net photosynthetic rate (Pnmax), light saturation point (LSP) and apparent quantum yield (AQY) in the control. Elevated temperature increased the Pnmaxand LSP values in P. anserine, while Pnmaxand LSP were decreased in E. nutans. Elevated CO2 increased the Pnmaxand LSP values in E. nutans and P. anserine, while the light compensation point (LCP) decreased; Elevated both temperature and CO2, the Pnmaxand LSP were all increased for E. nutans and P. anserine, but did not significantly affect AQY. We concluded that although elevated temperature had a photoinhibition for E. nutans, the interaction of short-term elevated CO2 concentration and temperature can improve the photosynthetic capacity of alpine plants. Key Words: elevated temperature; CO2 concentration; light response; alpine plants

  14. In vitro Effects of Ice, Skin Refrigerant, and CO2 Snow on Intra-Pulpal Temperature.

    Science.gov (United States)

    1980-06-11

    subsequent histological findings in the pulp. They found that 53% of teeth with partial or total pulp necrosis responded to the electrical pulp tester...showed histologically , as early as 1937, that the test was not only easy and sure, but safe for the pulp. Given the apparent usefulness of the CO2 pencil...probe was placed intrapulpally next to the dentin , directly under the spot where cold tests were applied, to allow temperature monitoring. The pulp

  15. Potential impact of increased temperature and CO2 on particulate dimethylsulfoniopropionate in the Southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    Peter A. Lee

    2011-06-01

    Full Text Available The potential impact of elevated sea surface temperature (SST and pCO2 on algal community structure and particulate dimethylsulfoniopropionate (DMSPp concentrations in the southeastern Bering Sea was examined using a shipboard “Ecostat” continuous culture system. The ecostat system was used to mimic the conditions projected to exist in the world's oceans by the end of this century (i.e. elevated pCO2 (750 ppm and elevated SST (ambient + 4°C. Two experiments were conducted using natural phytoplankton assemblages from the high-nutrient low-chlorophyll (HNLC central basin and from the middle domain of the southeastern continental shelf. At the HNLC site, the relative abundances of haptophytes and pelagophytes were higher and the relative abundance of diatoms lower under “greenhouse” conditions (i.e. combined 750 ppm CO2 and elevated temperature than control conditions (380 ppm CO2 and ambient temperature. This shift in algal community structure was accompanied by increases in DMSPp (2–3 fold, DMSPp:Chl a (2–3 fold and DMSP:PON (2 fold. At the continental shelf site, the changes in the relative abundances of haptophytes, pelagophytes and diatoms under “greenhouse” conditions were similar to those observed at the HNLC site, with 2.5 fold increases in DMSPp, 50–100% increases in DMSPp:Chl a and 1.8 fold increases in DMSP:PON. At both locations, changes in community structure and the DMSPp parameters were largely driven by increasing temperature. The observed changes were also consistent with the phytoplankton-DMS-albedo climate feedback mechanism proposed in the Charlson-Lovelock-Andreae-Warren (CLAW hypothesis.

  16. Photoprotective responses in a brown macroalgae Cystoseira tamariscifolia to increases in CO2 and temperature.

    Science.gov (United States)

    Celis-Plá, Paula S M; Martínez, Brezo; Korbee, Nathalie; Hall-Spencer, Jason M; Figueroa, Félix L

    2017-09-01

    Global warming and ocean acidification are increasingly affecting coastal ecosystems, with impacts that vary regionally depending upon local biogeography. Ocean acidification drives shifts in seaweed community dominance that depend on interactions with other factors such as light and nutrients. In this study, we investigated the photophysiological responses in the brown macroalgae species Cystoseira tamariscifolia (Hudson) Papenfuss with important structural role in the coastal Mediterranean communities. These algae were collected in the Cabo de Gata-Nijar Natural Park in ultraoligotrophic waters (algae exposed under high irradiance and less nutrient conditions) vs. those collected in the La Araña beach in oligotrophic waters (algae exposed at middle nutrient and irradiance conditions) in the Mediterranean Sea. They were incubated in mesocosms, under two levels of CO2; ambient (400-500 ppm) and high CO2 (1200-1300 ppm), combined with two temperatures (ambient temperature; 20 °C and ambient temperature + 4 °C; 24 °C) and the same nutrient conditions of the waters of the origin of macroalgae. Thalli from two sites on the Spanish Mediterranean coast were significantly affected by increases in pCO2 and temperature. The carotenoids (fucoxanthin, violaxanthin and β-carotene) contents were higher in algae from oligotrophic than that from ultraoligotrophic water, i.e., algae collected under higher nutrient conditions respect to less conditions, increase photoprotective pigments content. Thalli from both locations upregulated photosynthesis (as Fv/Fm) at increased pCO2 levels. Our study shows that ongoing ocean acidification and warming can increase photoprotection and photosynthesis in intertidal macroalgae. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. CORRELATION BETWEEN POLYMER PACKING AND GAS TRANSPORT PROPERTIES FOR CO2/N2 SEPARATION IN GLASSY FLUORINATED POLYIMIDE MEMBRANE

    Directory of Open Access Journals (Sweden)

    P. C. TAN

    2016-07-01

    Full Text Available Gas separation performance of a membrane highly hinges on its physical properties. In this study, the interplay between polymer packing of a membrane and its gas transport behaviours (permeability and selectivity was investigated through a series of 6FDA-DAM:DABA (3:2 polyimide membranes with different polymer compactness. The chemical structure and the polymer packing of the resulting membrane were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR and packing density measurement, respectively. CO2/N2 separation efficiency of the membrane was evaluated at 25oC with feed pressure up to 6 bar. N2 permeability was found to rely on the membrane’s packing density, which signified its greater dependence on molecular sieving. In contrast, sorption showed a more vital role in determining the CO2 permeability. In this work, the membrane with a final thickness of 97±2 µm had successfully surpassed the Robeson’s 2008 upper bound plot with a CO2 permeability of 83 Barrer and CO2/N2 selectivity of 97 at 3 bar permeation.

  18. Impacts of land surface properties and atmospheric CO2 on the Last Glacial Maximum climate: a factor separation analysis

    Directory of Open Access Journals (Sweden)

    G. Munhoven

    2009-06-01

    Full Text Available Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in most previous studies, we applied the separation method of U. Stein et P. Alpert 1993, in order to determine rigorously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO2 and of the vegetation cover change on the LGM climate. The separation of the ice cover and orographic contributions shows that the ice albedo effect is the main contributor to the cooling of the Northern Hemisphere, whereas orography has only a local cooling impact over the ice sheets. The expansion of ice cover in the Northern Hemisphere causes a disruption of the tropical precipitation, and a southward shift of the ITCZ. The orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere, leading to a redistribution of the precipitation, but weakly impacts the tropics. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere that further affects the tropical precipitation and reinforce the southward shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non-linear interactions that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weaker than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the south-west to

  19. Temperature and peat type control CO2 and CH4 production in Alaskan permafrost peats.

    Science.gov (United States)

    Treat, C C; Wollheim, W M; Varner, R K; Grandy, A S; Talbot, J; Frolking, S

    2014-08-01

    Controls on the fate of ~277 Pg of soil organic carbon (C) stored in permafrost peatland soils remain poorly understood despite the potential for a significant positive feedback to climate change. Our objective was to quantify the temperature, moisture, organic matter, and microbial controls on soil organic carbon (SOC) losses following permafrost thaw in peat soils across Alaska. We compared the carbon dioxide (CO2 ) and methane (CH4 ) emissions from peat samples collected at active layer and permafrost depths when incubated aerobically and anaerobically at -5, -0.5, +4, and +20 °C. Temperature had a strong, positive effect on C emissions; global warming potential (GWP) was >3× larger at 20 °C than at 4 °C. Anaerobic conditions significantly reduced CO2 emissions and GWP by 47% at 20 °C but did not have a significant effect at -0.5 °C. Net anaerobic CH4 production over 30 days was 7.1 ± 2.8 μg CH4 -C gC(-1) at 20 °C. Cumulative CO2 emissions were related to organic matter chemistry and best predicted by the relative abundance of polysaccharides and proteins (R(2) = 0.81) in SOC. Carbon emissions (CO2 -C + CH4 -C) from the active layer depth peat ranged from 77% larger to not significantly different than permafrost depths and varied depending on the peat type and peat decomposition stage rather than thermal state. Potential SOC losses with warming depend not only on the magnitude of temperature increase and hydrology but also organic matter quality, permafrost history, and vegetation dynamics, which will ultimately determine net radiative forcing due to permafrost thaw. © 2014 John Wiley & Sons Ltd.

  20. Rapid, broadband spectroscopic temperature measurement of CO2 using VIPA spectroscopy

    CERN Document Server

    Klose, Andrew; Cruz, Flavio C; Maser, Daniel L; Diddams, Scott A

    2016-01-01

    Time-resolved spectroscopic temperature measurements of a sealed carbon dioxide sample cell were realized with an optical frequency comb combined with a two-dimensional dispersive spectrometer. A supercontinuum laser source based on an erbium fiber mode-locked laser was employed to generate coherent light around 2000 nm (5000 cm-1). The laser was passed through a 12-cm long cell containing CO2, and the transmitted light was analyzed in a virtually imaged phased array- (VIPA-) based spectrometer. Broadband spectra spanning more than 100 cm-1 with a spectral resolution of roughly 0.075 cm-1 (2.2 GHz) were acquired with an integration period of 2 ms. The temperature of the CO2 sample was deduced from fitting a modeled spectrum to the line intensities of the experimentally acquired spectrum. Temperature dynamics on the time scale of milliseconds were observed with a temperature resolution of 2.6 K. The spectroscopically-deduced temperatures agreed with temperatures of the sample cell measured with a thermistor. P...

  1. Uncertainty of Wheat Water Use: Simulated Patterns and Sensitivity to Temperature and CO2

    Science.gov (United States)

    Cammarano, Davide; Roetter, Reimund P.; Asseng, Senthold; Ewert, Frank; Wallach, Daniel; Martre, Pierre; Hatfield, Jerry L.; Jones, James W.; Rosenzweig, Cynthia E.; Ruane, Alex C.; hide

    2016-01-01

    Projected global warming and population growth will reduce future water availability for agriculture. Thus, it is essential to increase the efficiency in using water to ensure crop productivity. Quantifying crop water use (WU; i.e. actual evapotranspiration) is a critical step towards this goal. Here, sixteen wheat simulation models were used to quantify sources of model uncertainty and to estimate the relative changes and variability between models for simulated WU, water use efficiency (WUE, WU per unit of grain dry mass produced), transpiration efficiency (Teff, transpiration per kg of unit of grain yield dry mass produced), grain yield, crop transpiration and soil evaporation at increased temperatures and elevated atmospheric carbon dioxide concentrations ([CO2]). The greatest uncertainty in simulating water use, potential evapotranspiration, crop transpiration and soil evaporation was due to differences in how crop transpiration was modelled and accounted for 50 of the total variability among models. The simulation results for the sensitivity to temperature indicated that crop WU will decline with increasing temperature due to reduced growing seasons. The uncertainties in simulated crop WU, and in particularly due to uncertainties in simulating crop transpiration, were greater under conditions of increased temperatures and with high temperatures in combination with elevated atmospheric [CO2] concentrations. Hence the simulation of crop WU, and in particularly crop transpiration under higher temperature, needs to be improved and evaluated with field measurements before models can be used to simulate climate change impacts on future crop water demand.

  2. An overview of how rubisco and carbohydrate metabolism may be regulated at elevated atmospheric [CO2] and temperature

    Directory of Open Access Journals (Sweden)

    G. BOWES

    2008-12-01

    Full Text Available Although atmospheric CO2 concentration ([C02] has been up to 16-fold higher than at present, the past several million years have seen atypically low values. Thus, modern-day plants are adapted to cope with a low [CO2]/[O2] ratio. The present [CO2] does not saturate C3 photosynthesis, so its doubling produces an "efficiency effect", but it is not always fully realized. Acclimation to high [C02] during growth can down-regulate photosynthesis, presumably to optimize carbon acquisition and utilization. A primary factor in acclimation is a reduction in rubisco. Two crops, rice and soybean, were used to study this phenomenon. Rice photosynthesis and growth peaked at 500 mmol mol-1, whereas soybean responded up to 990 mmol mol-1 . Rubisco concentration declined under CO2-enrichment and increasing temperatures, more so in rice than soybean. The rubisco kcat of rice was unaffected by growth [CO2]or temperature, but that from soybean was increased by both. In rice the capacity to handle carbohydrate, as measured by sucrose phosphate synthase activity was up-regulated by CO2 -enrichment, but not by temperature. Leaf carbohydrates were increased by [CO2], but decreased by higher temperatures, starch more so than sucrose. Even though C3 species differ in response to [CO2]and temperature, CO2 -enrichment can moderate adverse effects of temperature extremes.;

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

    Directory of Open Access Journals (Sweden)

    Chun-Ying Chen

    2017-02-01

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

  4. Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger.

    Science.gov (United States)

    Ma, Y; Barbano, D M

    2003-12-01

    Raw skim milk, with or without added CO2, was heated, held, and cooled in a small pilot-scale tubular heat exchanger (372 ml/min). The experiment was replicated twice, and, for each replication, milk was first carbonated at 0 to 1 degree C to contain 0 (control), 600, 1200, 1800, and 2400 ppm added CO2 using a continuous carbonation unit. After storage at 0 to 1 degree C, portions of milk at each CO2 concentration were heated to 40, 56, 72, and 80 degrees C, held at the desired temperature for 30 s (except 80 degrees C, holding 20 s) and cooled to 0 to 1 degree C. At each temperature, five pressures were applied: 69, 138, 207, 276, and 345 kPa. Pressure was controlled with a needle valve at the heat exchanger exit. Both the pressure gauge and pH probe were inline at the end of the holding section. Milk pH during heating depended on CO2 concentration, temperature, and pressure. During heating of milk without added CO2, pH decreased linearly as a function of increasing temperature but was independent of pressure. In general, the pH of milk with added CO2 decreased with increasing CO2 concentration and pressure. For milk with added CO2, at a fixed CO2 concentration, the effect of pressure on pH decrease was greater at a higher temperature. At a fixed temperature, the effect of pressure on pH decrease was greater for milk with a higher CO2 concentration. Thermal death of bacteria during pasteurization of milk without added CO2 is probably due not only to temperature but also to the decrease in pH that occurs during the process. Increasing milk CO2 concentration and pressure decreases the milk pH even further during heating and may further enhance the microbial killing power of pasteurization.

  5. Biomass Production Potential of a Wastewater Alga Chlorella vulgaris ARC 1 under Elevated Levels of CO2 and Temperature

    Directory of Open Access Journals (Sweden)

    Senthil Chinnasamy

    2009-02-01

    Full Text Available The growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (ranging from 0.036 to 20% and temperature (30, 40 and 50oC. The highest chlorophyll concentration (11 µg mL-1 and biomass (210 µg mL-1, which were 60 and 20 times more than that of C. vulgaris at ambient CO2 (0.036%, were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them. Results showed that the optimum temperature for biomass production was 30oC under elevated CO2 (6%. Although increases in temperature above 30oC resulted in concomitant decrease in growth response, their adverse effects were significantly subdued at elevated CO2. There were also differential responses of the alga, assessed in terms of NaH14CO3 uptake and carbonic anhydrase activity, to increases in temperature at elevated CO2. The results indicated that Chlorella vulgaris grew better at elevated CO2 level at 30oC, albeit with lesser efficiencies at higher temperatures.

  6. Both experimental study and numerical modelling of the effect of temperature gradient on CO2 injection

    Science.gov (United States)

    Corvisier, J.; Lagneau, V.; Jobard, E.; Sterpenich, J.; Pironon, J.

    2010-12-01

    CO2 injection and underground storage obviously requires dealing with temperature differences between the injection well and the reservoir. Temperature enhances both species transport and reactions kinetics, while CO2 solubility also greatly decreases with temperature. This point could be of great importance especially in wellbore surroundings, although it has not been the subject of devoted studies up to now. To assess this issue, an experimental set up, COTAGES, has been designed (Fig.1). It consists in a 0.72m-long cylindrical autoclave (the diameter is 2.1cm) that can be filled with 12 fiberglass/teflon packets containing 12.5 grams of mineral grains and a pre-equilibrated saline aqueous solution. When loaded, one end of the autoclave is heaten up and maintained at 100°C. After having reached a steady-state, the other end is around 30°C. Finally, CO2 is injected in the cold zone (100 bars) and, from this moment, the experiment lasts 1 month while both pressure and temperatures (3 zones) are being monitored. The first results show the same general trend for both a reservoir rock such as oolitic limestone (Lavoux, France) and clay minerals such as COx argillite (Lundin, France). In these two experiments, a global mass loss is observed for all the packets except for those comprised between 75 and 95°C. There, a mass gain is noted and is remarkably important in the case of clay (greater than 11.5%). The greater losses are recorded around 65-70°C and are also of greater importance for COx clay (up to 10.0%). During the whole experiments, quite important variations of the total pressure are observed. Even if they are partly related to CO2 dissolution into water and to temperature variations (due to regulation), they shall also depend on involved chemical reactions. Indeed, after injection, pressure drastically decreases (up to 50 bar less). Since CO2 solubility is higher in the cold zone (more than 4 times), the aqueous solution gets more acidic there. It leads

  7. Gravimetric analysis of CO2 adsorption on activated carbon at various pressures and temperatures using piezoelectric microcantilevers.

    Science.gov (United States)

    Jin, Yusung; Lee, Dongkyu; Lee, Sangkyu; Moon, Wonkyu; Jeon, Sangmin

    2011-09-15

    We investigated the adsorption and desorption of CO(2) on activated carbon using piezoelectric microcantilevers. After coating the free end of a cantilever with activated carbon, variations in the resonance frequency of the cantilever were measured as a function of CO(2) pressure, which is related to mass changes due to the adsorption or desorption of CO(2). The pressure-dependent viscous damping effects were compensated in the calculation of the CO(2) adsorption capacity of the activated carbon by comparing the frequency differences between the coated and uncoated cantilevers. The mass sensitivity of the piezoelectric cantilever was found to be better than 1 pg. The fractional coverage of CO(2) agreed with a Langmuir adsorption isotherm, indicating that a submonolayer of adsorbed CO(2) occurred on the surface of the activated carbon under the experimental conditions. The heat of adsorption was determined using the Clausius-Clapeyron relation and the fractional coverage of CO(2) at various temperatures and pressures.

  8. Which are the most important parameters for modelling carbon assimilation in boreal Norway spruce under elevated [CO(2)] and temperature conditions?

    Science.gov (United States)

    Hall, Marianne; Medlyn, Belinda E; Abramowitz, Gab; Franklin, Oskar; Räntfors, Mats; Linder, Sune; Wallin, Göran

    2013-11-01

    Photosynthesis is highly responsive to environmental and physiological variables, including phenology, foliage nitrogen (N) content, atmospheric CO2 concentration ([CO2]), irradiation (Q), air temperature (T) and vapour pressure deficit (D). Each of these responses is likely to be modified by long-term changes in climatic conditions such as rising air temperature and [CO2]. When modelling photosynthesis under climatic changes, which parameters are then most important to calibrate for future conditions? To assess this, we used measurements of shoot carbon assimilation rates and microclimate conditions collected at Flakaliden, northern Sweden. Twelve 40-year-old Norway spruce trees were enclosed in whole-tree chambers and exposed to elevated [CO2] and elevated air temperature, separately and in combination. The treatments imposed were elevated temperature, +2.8 °C in July/August and +5.6 °C in December above ambient, and [CO2] (ambient CO2 ∼370 μ mol mol(-1), elevated CO2 ∼700 μ mol mol(-1)). The relative importance of parameterization of Q, T and D responses for effects on the photosynthetic rate, expressed on a projected needle area, and the annual shoot carbon uptake was quantified using an empirical shoot photosynthesis model, which was developed and fitted to the measurements. The functional form of the response curves was established using an artificial neural network. The [CO2] treatment increased annual shoot carbon (C) uptake by 50%. Most important was effects on the light response curve, with a 67% increase in light-saturated photosynthetic rate, and a 52% increase in the initial slope of the light response curve. An interactive effect of light saturated photosynthetic rate was found with foliage N status, but no interactive effect for high temperature and high CO2. The air temperature treatment increased the annual shoot C uptake by 44%. The most important parameter was the seasonality, with an elongation of the growing season by almost 4

  9. Enhanced Intermediate-Temperature CO2 Splitting Using Nonstoichiometric Ceria and Ceria-Zirconia

    KAUST Repository

    Zhao, Zhenlong

    2017-08-24

    CO2 splitting via thermo-chemical or reactive redox has emerged as a novel and promising carbon-neutral energy solution. Its performance depends critically on the properties of the oxygen carriers (OC). Ceria is recognized as one of the most promising OC candidates, because of its fast chemistry, high ionic diffusivity, and large oxygen storage capacity. The fundamental surface ion-incorporation pathways, along with the role of surface defects and the adsorbates remains largely unknown. This study presents a detailed kinetics study of CO2 splitting using CeO2 and Ce0.5Zr0.5O2 (CZO) in the temperature range 600-900℃. Given our interest in fuel-assisted reduction, we limit our study to relatively lower temperatures to avoid excessive sintering and the need for high temperature heat. Compared to what has been reported previously, we observe higher splitting kinetics, resulting from the utilization of fine particles and well-controlled experiments which ensure a surface-limited-process. The peak rates with CZO are 85.9 μmole g–1s–1 at 900℃ and 61.2 μmole g–1s–1 at 700℃, and those of CeO2 are 70.6 μmole g–1s–1 and 28.9 μmole g–1s–1. Kinetics models are developed to describe the ion incorporation dynamics, with consideration of CO2 activation and the charge transfer reactions. CO2 activation energy is found to be – 120 kJ mole-1 for CZO, half of that for CeO2, while CO desorption energetics is analogous among the two samples with the value of ~160 kJ mole-1. The charge-transfer process is found to be the rate-limiting step for CO2 splitting. The evolution of CO32- with surface Ce3+ is examined based on the modeled kinetics. We show that the concentration of CO32- varies with Ce3+ in a linear-flattened-decay pattern, resulting from a mismatch between the kinetics of the two reactions. Our study provides new insights into the significant role of the surface defects and adsorbates in determining the splitting kinetics.

  10. An energy balance perspective on regional CO2-induced temperature changes in CMIP5 models

    Science.gov (United States)

    Räisänen, Jouni

    2017-05-01

    An energy balance decomposition of temperature changes is conducted for idealized transient CO2-only simulations in the fifth phase of the Coupled Model Intercomparison Project. The multimodel global mean warming is dominated by enhanced clear-sky greenhouse effect due to increased CO2 and water vapour, but other components of the energy balance substantially modify the geographical and seasonal patterns of the change. Changes in the net surface energy flux are important over the oceans, being especially crucial for the muted warming over the northern North Atlantic and for the seasonal cycle of warming over the Arctic Ocean. Changes in atmospheric energy flux convergence tend to smooth the gradients of temperature change and reduce its land-sea contrast, but they also amplify the seasonal cycle of warming in northern North America and Eurasia. The three most important terms for intermodel differences in warming are the changes in the clear-sky greenhouse effect, clouds, and the net surface energy flux, making the largest contribution to the standard deviation of annual mean temperature change in 34, 29 and 20 % of the world, respectively. Changes in atmospheric energy flux convergence mostly damp intermodel variations of temperature change especially over the oceans. However, the opposite is true for example in Greenland and Antarctica, where the warming appears to be substantially controlled by heat transport from the surrounding sea areas.

  11. CO2 emission factors for waste incineration: Influence from source separation of recyclable materials

    DEFF Research Database (Denmark)

    Larsen, Anna Warberg; Astrup, Thomas

    2011-01-01

    variations between emission factors for different incinerators, but the background for these variations has not been thoroughly examined. One important reason may be variations in collection of recyclable materials as source separation alters the composition of the residual waste incinerated. The objective...... of this study was to quantify the importance of source separation for determination of emission factors for incineration of residual household waste. This was done by mimicking various source separation scenarios and based on waste composition data calculating resulting emission factors for residual waste...... waste; however the fossil carbon ratio of the waste after source separation was found to be appropriately correlated with the emission factor. Based on the results, it is recommended to carefully evaluate the source separation and collection systems behind reported literature values when comparing...

  12. Influence of vertical temperature contrasts and diel cycles on near-surface seawater pCO2

    Science.gov (United States)

    Matthews, Robin; deYoung, Brad

    2016-04-01

    While the oceanic mixed layer is sometimes assumed to be of vertically-uniform temperature, it is well-known that considerable temperature gradients (>0.1C/m) can develop within its upper few meters, particularly in the tropics during daytime. Given that the partial pressure of CO2 in seawater (pCO2sw) is strongly temperature-dependent, ceteris paribus (all else being equal), we would expect to observe sizeable corresponding vertical pCO2sw gradients under such situations. If prevalent and persistent, such gradients could affect the accuracy of large-scale air-sea CO2 flux estimates since, while intended to be representative of the sea surface skin, the pCO2sw measurements used to compute these are typically from underway systems sampling at 2-4m depth. Vertical variability in pCO2sw could thus be an important but as yet, poorly quantified uncertainty in air-sea CO2 flux estimates. As a first step towards assessing this uncertainty, we derive a global gridded monthly climatology for the peak daily vertical temperature contrast between the upper (0-2m) and lower (2-10m) sea surface and compute the corresponding vertical pCO2sw differences these would cause, ceteris paribus. The latter are an estimate of the temperature-driven pCO2 contrast we would expect to find in a given month between the upper sea surface and the sampling depth of an underway system at the time of the peak temperature contrast in the daily cycle. In addition, we construct a monthly climatology for the amplitude of diel variation in upper sea temperature and compute the corresponding diel pCO2sw amplitudes these would generate, ceteris paribus. While these analyses reveal the locations and months for which vertical temperature contrasts and diel cycles are likely to exert a strong influence on pCO2sw, temperature is only one factor influencing this carbonate chemistry parameter. In situ measurements are required to reveal the actual dynamics of pCO2sw under the influence of all competing factors

  13. Effect of temperature of CO2 injection on the pH and freezing point of milks and creams.

    Science.gov (United States)

    Ma, Y; Barbano, D M

    2003-05-01

    The objectives of this study were to measure the impact of CO2 injection temperature (0 degree C and 40 degrees C) on the pH and freezing point (FP) of (a) milks with different fat contents (i.e., 0, 15, 30%) and (b) creams with 15% fat but different fat characteristics. Skim milk and unhomogenized creams containing 15 and 30% fat were prepared from the same batch of whole milk and were carbonated at 0 and 40 degrees C in a continuous flow CO2 injection unit (230 ml/min). At 0 degree C, milk fat was mostly solid; at 40 degrees C, milk fat was liquid. At the same total CO2 concentration with CO2 injection at 0 degree C, milk with a higher fat content had a lower pH and FP, while with CO2 injection at 40 degrees C, milks with 0%, 15%, and 30% fat had the same pH. This indicated that less CO2 was dissolved in the fat portion of the milk when the CO2 was injected at 0 degree C than when it was injected at 40 degrees C. Three creams, 15% unhomogenized cream, 15% butter oil emulsion in skim milk, and 15% vegetable oil emulsion in skim milk were also carbonated and analyzed as described above. Vegetable oil was liquid at both 0 and 40 degrees C. At a CO2 injection temperature of 0 degree C, the 15% vegetable oil emulsion had a slightly higher pH than the 15% butter oil emulsion and the 15% unhomogenized cream, indicating that the liquid vegetable oil dissolved more CO2 than the mostly solid milk fat and butter oil. No difference in the pH or FP of the 15% unhomogenized cream and 15% butter oil emulsion was observed when CO2 was injected at 0 degree C, suggesting that homogenization or physical dispersion of milk fat globules did not influence the amount of CO2 dissolved in milk fat at a CO2 injection temperature of 0 degree C. At a CO2 injection temperature of 40 degrees C and at the same total CO2 concentration, the 15% unhomogenized cream, 15% vegetable oil emulsion, and 15% butter oil emulsion had similar pH. At the same total concentration of CO2 in cream, injection

  14. Effects of temperature and gas-liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO2 reduction electrocatalysts.

    Science.gov (United States)

    Lobaccaro, Peter; Singh, Meenesh R; Clark, Ezra Lee; Kwon, Youngkook; Bell, Alexis T; Ager, Joel W

    2016-09-29

    In the last few years, there has been increased interest in electrochemical CO2 reduction (CO2R). Many experimental studies employ a membrane separated, electrochemical cell with a mini H-cell geometry to characterize CO2R catalysts in aqueous solution. This type of electrochemical cell is a mini-chemical reactor and it is important to monitor the reaction conditions within the reactor to ensure that they are constant throughout the study. We show that operating cells with high catalyst surface area to electrolyte volume ratios (S/V) at high current densities can have subtle consequences due to the complexity of the physical phenomena taking place on electrode surfaces during CO2R, particularly as they relate to the cell temperature and bulk electrolyte CO2 concentration. Both effects were evaluated quantitatively in high S/V cells using Cu electrodes and a bicarbonate buffer electrolyte. Electrolyte temperature is a function of the current/total voltage passed through the cell and the cell geometry. Even at a very high current density, 20 mA cm-2, the temperature increase was less than 4 °C and a decrease of CO2 concentration is predicted. In contrast, limits on the CO2 gas-liquid mass transfer into the cells produce much larger effects. By using the pH in the cell to measure the CO2 concentration, significant undersaturation of CO2 is observed in the bulk electrolyte, even at more modest current densities of 10 mA cm-2. Undersaturation of CO2 produces large changes in the faradaic efficiency observed on Cu electrodes, with H2 production becoming increasingly favored. We show that the size of the CO2 bubbles being introduced into the cell is critical for maintaining the equilibrium CO2 concentration in the electrolyte, and we have designed a high S/V cell that is able to maintain the near-equilibrium CO2 concentration at current densities up to 15 mA cm-2.

  15. Shifts in microbial trophic strategy explain different temperature sensitivity of CO2 flux under constant and diurnally varying temperature regimes.

    Science.gov (United States)

    Bai, Zhen; Xie, Hongtu; Kao-Kniffin, Jenny; Chen, Baodong; Shao, Pengshuai; Liang, Chao

    2017-05-01

    Understanding soil CO2 flux temperature sensitivity (Q10) is critical for predicting ecosystem-level responses to climate change. Yet, the effects of warming on microbial CO2 respiration still remain poorly understood under current Earth system models, partly as a result of thermal acclimation of organic matter decomposition. We conducted a 117-day incubation experiment under constant and diurnally varying temperature treatments based on four forest soils varying in vegetation stand and soil horizon. Our results showed that Q10 was greater under varying than constant temperature regimes. This distinction was most likely attributed to differences in the depletion of available carbon between constant high and varying high-temperature treatments, resulting in significantly higher rates of heterotrophic respiration in the varying high-temperature regime. Based on 16S rRNA gene sequencing data using Illumina, the varying high-temperature regime harbored higher prokaryotic alpha-diversity, was more dominated by the copiotrophic strategists and sustained a distinct community composition, in comparison to the constant-high treatment. We found a tightly coupled relationship between Q10 and microbial trophic guilds: the copiotrophic prokaryotes responded positively with high Q10 values, while the oligotrophs showed a negative response. Effects of vegetation stand and soil horizon consistently supported that the copiotrophic vs oligotrophic strategists determine the thermal sensitivity of CO2 flux. Our observations suggest that incorporating prokaryotic functional traits, such as shifts between copiotrophy and oligotrophy, is fundamental to our understanding of thermal acclimation of microbially mediated soil organic carbon cycling. Inclusion of microbial functional shifts may provide the potential to improve our projections of responses in microbial community and CO2 efflux to a changing environment in forest ecosystems. © FEMS 2017. All rights reserved. For permissions

  16. Plasticization-resistant hollow fiber membranes for CO2/CH4 separation based on a thermally crosslinkable polyimide

    KAUST Repository

    Chen, Chien-Chiang

    2011-10-01

    Decarboxylation-induced thermal crosslinking has been demonstrated to be effective for stabilizing membranes against plasticization in dense films. This study extends this promising crosslinking approach from dense films to industrially relevant asymmetric hollow fiber membranes. Crosslinkable asymmetric hollow fiber membranes were spun from a carboxylic acid containing polyimide, 6FDA-DAM:DABA. Dope and spinning conditions were optimized to obtain fibers with a defect-free selective skin layer. It is found that slightly defective fibers suffered severe selectivity loss after thermal crosslinking, suggesting that defect-free property is essential to the performance of the resulting crosslinked hollow fiber membranes. The crosslinked fibers were tested for CO 2/CH 4 separation. The excellent plasticization resistance under high pressure feeds (with highest CO 2 partial pressure of 400psia) suggests that these robust membranes are promising for aggressive natural gas purification. © 2011 Elsevier B.V.

  17. EXPERIMENTAL DESIGN AND RESPONSE SURFACE MODELING OF PI/PES-ZEOLITE 4A MIXED MATRIX MEMBRANE FOR CO2 SEPARATION

    Directory of Open Access Journals (Sweden)

    T. D. KUSWORO

    2015-09-01

    Full Text Available This paper investigates the effect of preparation of polyimide/polyethersulfone (PI/PES blending-zeolite mixed matrix membrane through the manipulation of membrane production variables such as polymer concentration, blending composition and zeolite loading. Combination of central composite design and response surface methodology were applied to determine the main effect and interaction effects of these variables on membrane separation performance. The quadratic models between each response and the independent parameters were developed and the response surface models were tested with analysis of variance (ANOVA. In this study, PI/ (PES–zeolite 4A mixed matrix membranes were casted using dry/wet phase inversion technique. The separation performance of mixed matrix membrane had been tested using pure gases such as CO2 and CH4. The results showed that zeolite loading was the most significant variable that influenced the CO2/CH4 selectivity among three variables and the experimental results were in good agreement with those predicted by the proposed regression models. The gas separation performance of the membrane was relatively higher as compare to polymeric membrane. Therefore, combination of central composite design and response surface methodology can be used to prepare optimal condition for mixed matrix membrane fabrication. The incorporation of 20 wt% zeolite 4A into 25 wt% of PI/PES matrix had resulted in a high separation performance of membrane material.

  18. Mixed-linker zeolitic imidazolate framework mixed-matrix membranes for aggressive CO2 separation from natural gas

    KAUST Repository

    Thompson, Joshua A.

    2014-07-01

    Zeolitic imidazolate framework (ZIF) materials are a promising subclass of metal-organic frameworks (MOF) for gas separations. However, due to the deleterious effects of gate-opening phenomena associated with organic linker rotation near the limiting pore apertures of ZIFs, there have been few demonstrations of improved gas separation properties over pure polymer membranes when utilizing ZIF materials in composite membranes for CO2-based gas separations. Here, we report a study of composite ZIF/polymer membranes, containing mixed-linker ZIF materials with ZIF-8 crystal topologies but composed of different organic linker compositions. Characterization of the mixed-linker ZIFs shows that the mixed linker approach offers control over the porosity and pore size distribution of the materials, as determined from nitrogen physisorption and Horváth-Kawazoe analysis. Single gas permeation measurements on mixed-matrix membranes reveal that inclusion of mixed-linker ZIFs yields membranes with better ideal CO2/CH4 selectivity than membranes containing ZIF-8. This improvement is shown to likely occur from enhancement in the diffusion selectivity of the membranes associated with controlling the pore size distribution of the ZIF filler. Mixed-gas permeation experiments show that membranes with mixed-linker ZIFs display an effective plasticization resistance that is not typical of the pure polymeric matrix. Overall, we demonstrate that mixed-linker ZIFs can improve the gas separation properties in composite membranes and may be applicable to aggressive CO2 concentrations in natural gas feeds. © 2013 Elsevier Inc. All rights reserved.

  19. [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.

  20. Analysis of CO2 separation and simulation of a partially wetted hollow fiber membrane contactor.

    Science.gov (United States)

    Keshavarz, P; Fathikalajahi, J; Ayatollahi, S

    2008-04-15

    A steady state model was developed for a microporous hollow fiber membrane contactor operated under partially wetted conditions accompanied by chemical reactions, to analyze CO2 absorption into the aqueous solution of diethanolamine (DEA). The proposed diffusion-reaction model contains reversible chemical reactions in the liquid bulk as well as wetted parts of the membrane pores. A numerical scheme was employed to solve the simultaneous nonlinear mathematical expressions, and the results were validated with experimental data in the literature. The gas phase concentration and velocity profile in axial direction inside the shell, liquid concentration profile in axial and radial directions inside the fibers, and also those within the wetted parts of the pores were predicted by using the model. The results of the model and proposed numerical scheme show that membrane wetting, even in very low fractions, can decrease the absorption flux significantly. The wetting fraction of membrane was predicted both with and without consideration of chemical reactions inside the wetted pores. The results indicate that the chemical reactions inside the wetted pores, which have been disregarded in the literature, have considerable effects on the prediction of membrane wetting fraction.

  1. Effects of Single and Multifactor Treatments with Elevated Temperature, CO2 and Ozone on Oilseed Rape and Barley

    DEFF Research Database (Denmark)

    Clausen, Sabine Karin; Frenck, Georg; van der Linden, Leon Gareth

    2011-01-01

    barley (Hordeum vulgare L.). Seven genotypes of each species were cultivated in six single- and multifactor treatments with ambient or elevated CO2 (385 ppm and 700 ppm), O3 (20 ppb and 60 ppb) and temperature (12/19 °C and 17/24 °C). Growth and production parameters were measured. Elevated CO2 increased...

  2. New Meets Old: Accelerating Membrane-based CO2 Separation by Soluble Nanoporous Polymer Networks Produced Via Mechanochemical Oxidative Coupling.

    Science.gov (United States)

    Zhu, Xiang; Hua, Yinying; Tian, Chengcheng; Abney, Carter W; Zhang, Peng; Jin, Tian; Liu, Gongping; Browning, Katie L; Sacci, Robert L; Veith, Gabriel M; Zhou, Hong-Cai; Jin, Wanqin; Dai, Sheng

    2017-12-29

    Achieving homogeneous dispersion of nanoporous fillers within membrane architectures remains a great challenge for mixed-matrix membrane (MMMs) technology. Imparting solution processability of nanoporous materials would help advance the development of MMMs for membrane-based gas separations. For the first time, we report a novel mechanochemical-assisted oxidative coupling polymerization strategy to create a new family of soluble nanoporous polymer networks. The solid-state ball-milling methodology affords inherent control over polymer growth and therefore provides tunable solubility in the resulting nanoporous frameworks. MMM-based CO2/CH4 separation performance was significantly accelerated by these new soluble fillers. We anticipate this facile protocol will facilitate new possibilities for the rational design and synthesis of soluble nanoporous polymer networks and promote their applications in membrane-based gas separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Effect of solvents on the morphology and performance of Polyethersulfone (PES) polymeric membranes material for CO2/CH4 separation

    Science.gov (United States)

    Ahmad, M. S.; Mohshim, D. F.; Nasir, R.; Mannan, H. A.; Mukhtar, H.

    2018-01-01

    Membrane technology has several advantages such as the ability to separate chemical species within compact plant footprints, low thermal energy requirements and simple process flow schemes. By optimizing the available materials and analysis, this work comes with the objective to synthesize the polymeric membrane, which has the best separation performance. In this work, three (03) membranes have been synthesized and a comparative analysis were conducted based on different types of solvent namely N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), N-methyl-2-pyrrolidinone (NMP). In characterizing the synthesized membrane, Thermo Gravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were used. A comparative study was carried out to compare the effects of each solvent towards CO2 separation performance.

  4. Expression of calcification and metabolism-related genes in response to elevated pCO2 and temperature in the reef-building coral Acropora millepora.

    Science.gov (United States)

    Rocker, Melissa M; Noonan, Sam; Humphrey, Craig; Moya, Aurelie; Willis, Bette L; Bay, Line K

    2015-12-01

    Declining health of scleractinian corals in response to deteriorating environmental conditions is widely acknowledged, however links between physiological and functional genomic responses of corals are less well understood. Here we explore growth and the expression of 20 target genes with putative roles in metabolism and calcification in the branching coral, Acropora millepora, in two separate experiments: 1) elevated pCO2 (464, 822, 1187 and 1638 μatm) and ambient temperature (27°C), and 2) elevated pCO2 (490 and 822 μatm) and temperature (28 and 31 °C). After 14 days of exposure to elevated pCO2 and ambient temperatures, no evidence of differential expression of either calcification or metabolism genes was detected between control and elevated pCO2 treatments. After 37 days of exposure to control and elevated pCO2, Ubiquinol-Cytochrome-C Reductase Subunit 2 gene (QCR2; a gene involved in complex III of the electron chain transport within the mitochondria and critical for generation of ATP) was significantly down-regulated in the elevated pCO2 treatment in both ambient and elevated temperature treatments. Overall, the general absence of a strong response to elevated pCO2 and temperature by the other 19 targeted calcification and metabolism genes suggests that corals may not be affected by these stressors on longer time scales (37 days). These results also highlight the potential for QCR2 to act as a biomarker of coral genomic responses to changing environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Dissolution kinetics of magnesium hydroxide for CO2 separation from coal-fired power plants.

    Science.gov (United States)

    Bharadwaj, Hari Krishna; Lee, Joo-Youp; Li, Xin; Liu, Zhouyang; Keener, Tim C

    2013-04-15

    The dissolution of magnesium hydroxide in water for the release of magnesium and hydroxyl ions into the solution to maintain suitable alkalinity is a crucial step in the Mg(OH)2-based CO2 absorption process. In this study, the rate of dissolution of Mg(OH)2 was investigated under different operating conditions using a pH stat apparatus. The dissolution process was modeled using a shrinking core model and the overall Mg(OH)2 dissolution process was found to be controlled by the surface chemical reaction of Mg(OH)2 with H(+) ions. Under the chemical reaction control regime, the dissolution of Mg(OH)2 in alkaline conditions was found not to follow a first-order reaction, and the fractional order of reaction was estimated to lie between 0.20 and 0.31. This suggests that the dissolution reaction is a non-elementary reaction, consisting of a sequence of elementary reactions, via most likely forming a surface magnesium complex. The true activation energy value of 76 ± 11 kJ/gmol was found to be almost twice as much as the observed activation energy value of 42 ± 6 kJ/gmol determined at pH 8.6, and was comparable with the previously reported values. The particle sizes predicted from the intrinsic kinetics determined from the model were in good agreement with the experimentally measured particle sizes during the dissolution process. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Late Oligocene decoupling of temperature and pCO2: Insights from TEX86 paleothermometry

    Science.gov (United States)

    O'Brien, C. L.; Pagani, M.

    2016-12-01

    Current paleo-proxy reconstructions for the late Oligocene ( 28-23 Ma) indicate a decoupling of temperature and pCO2. Specifically, benthic oxygen isotope data suggest either stable conditions or warming/deglaciation, while alkenone-based pCO2 estimates indicate a decline from 700 to 400 ppm. Existing sea surface temperature (SST) proxy estimates for this interval are sparse and the appearance of decoupling could be fallacious. Using late Oligocene marine sediments from a range of oceanographic and latitudinal settings, in particular Atlantic Ocean sites ODP 929A (5°N), DSDP 608 (42°N) and DSDP 516F (30°S), we are applying the TEX86 paleothermometer to provide improved constraints on late Oligocene warmth. Thought to originate mainly from planktonic, ammonia-oxidizing Thaumarchaeota, the sedimentary TEX86 signal is complicated by potential influences from additional sources and non-thermal effects (e.g., water chemistry, nutrient dynamics, growth stage and ecology). Thus, we are simultaneously testing assumptions regarding the fidelity of the TEX86 paleo-SST proxy. Our new TEX86H-SST data from Atlantic site ODP 929A indicate stable SSTs in the tropics (often reflective of global conditions) during the late Oligocene, with no reduction in SST coincident with declining pCO2 during the period 28-24 Ma. Importantly, TEX86H-SST data show a lack of coherence with latitude exemplified by similar stable SSTs, 28°C, at tropical and southern mid-latitude Atlantic sites ODP 929 and DSDP 516F, respectively. This absence of a decrease in SST with increasing site latitude suggests that additional non-thermal factors may be influencing the TEX86 signal at certain locations and/or a need for regional-based TEX86-SST calibrations. Indeed, if our tropical TEX86-SST reconstructions ( 28°C) are valid then this would imply the late Oligocene tropical Atlantic was no warmer than the Pliocene, contradicting multiple lines of evidence that the world was warmer (e.g., higher pCO2

  7. ENHANCED HYDROGEN PRODUCTION INTEGRATED WITH CO2 SEPARATION IN A SINGLE-STAGE REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Himanshu Gupta; Mahesh Iyer; Bartev Sakadjian; Liang-Shih Fan

    2005-03-10

    Hydrogen production cannot be maximized from fossil fuels (gas/coal) via the WGS reaction at high temperatures as the WGS-equilibrium constant K{sub WGS} (= [CO{sub 2}][H{sub 2}]/[CO][H{sub 2}O]), falls with increasing temperatures. However, CO{sub 2} removal down to ppm levels by the carbonation of CaO to CaCO{sub 3} in the temperature range 650-850 C, leads to the possibility of stoichiometric H{sub 2} production at high temperature/pressure conditions and at low steam to fuel ratios. Further, CO{sub 2} is also captured in the H{sub 2} generation process, making this coal to hydrogen process compatible with CO{sub 2} sequestration goals. While microporous CaO sorbents attain <50% conversion over cyclical carbonation-calcination, the OSU-patented, mesoporous CaO sorbents are able to achieve >95% conversion. Novel calcination techniques could lead to an ever-smaller footprint, single-stage reactors that achieve maximum theoretical H{sub 2} production at high temperatures and pressures for on/off site usage. Experimental results indicate that the PCC-CaO sorbent is able to achieve complete conversion of CO for 240 seconds as compared to only a few seconds with CaO derived from natural sources.

  8. Molecular simulation and mathematical modelling of glass transition temperature depression induced by CO2 plasticization in Polysulfone membranes

    Science.gov (United States)

    Lock, S. S. M.; Lau, K. K.; Lock Sow Mei, Irene; Shariff, A. M.; Yeong, Y. F.; Bustam, A. M.

    2017-08-01

    A sequence of molecular modelling procedure has been proposed to simulate experimentally validated membrane structure characterizing the effect of CO2 plasticization, whereby it can be subsequently employed to elucidate the depression in glass transition temperature (Tg ). Based on the above motivation, unswollen and swollen Polysulfone membrane structures with different CO2 loadings have been constructed, whereby the accuracy has been validated through good compliance with experimentally measured physical properties. It is found that the presence of CO2 constitutes to enhancement in polymeric chain relaxation, which consequently promotes the enlargement of molecular spacing and causes dilation in the membrane matrix. A series of glass transition temperature treatment has been conducted on the verified molecular structure to elucidate the effect of CO2 loadings to the depression in Tg induced by plasticization. Subsequently, a modified Michealis-Menten (M-M) function has been implemented to quantify the effect of CO2 loading attributed to plasticization towards Tg .

  9. ELEVATED TEMPERATURE, SOIL MOISTURE AND SEASONALITY BUT NOT CO2 AFFECT CANOPY ASSIMILATION AND SYSTEM RESPIRATION IN SEEDLING DOUGLAS-FIR ECOSYSTEMS

    Science.gov (United States)

    We investigated the effects of elevated atmospheric CO2 and air temperature on C cycling in trees and associated soil system, focusing on canopy CO2 assimilation (Asys) and system CO2 loss through respiration (Rsys). We hypothesized that both elevated CO2 and elevated temperature...

  10. Compensatory water effects link yearly global land CO2 sink changes to temperature

    Science.gov (United States)

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R.; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K.; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  11. Compensatory Water Effects Link Yearly Global Land CO2 Sink Changes to Temperature

    Science.gov (United States)

    Jung, Martin; Reichstein, Markus; Tramontana, Gianluca; Viovy, Nicolas; Schwalm, Christopher R.; Wang, Ying-Ping; Weber, Ulrich; Weber, Ulrich; Zaehle, Soenke; Zeng, Ning; hide

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems13. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales314. Here we use empirical models based on eddy covariance data15 and process-based models16,17 to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance36,9,11,12,14. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  12. [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.

  13. ENHANCED HYDROGEN PRODUCTION INTEGRATED WITH CO2 SEPARATION IN A SINGLE-STAGE REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Himanshu Gupta; Mahesh Iyer; Bartev Sakadjian; Liang-Shih Fan

    2005-04-01

    Hydrogen production by the water gas shift reaction (WGSR) is equilibrium limited due to thermodynamic constrains. However, this can be overcome by continuously removing the product CO{sub 2}, thereby driving the WGSR in the forward direction to enhance hydrogen production. This project aims at using a high reactivity, mesoporous calcium based sorbent (PCC-CaO) for removing CO{sub 2} using reactive separation scheme. Preliminary results have shown that PCC-CaO dominates in its performance over naturally occurring limestone towards enhanced hydrogen production. However, maintenance of high reactivity of the sorbent over several reaction-regeneration cycles warrants effective regeneration methods. We have identified sub-atmospheric calcination (vacuum) as vital regeneration technique that helps preserve the sorbent morphology. Sub-atmospheric calcination studies reveal the significance of vacuum level, diluent gas flow rate, thermal properties of diluent gas, and sorbent loading on the kinetics of calcination and the morphology of the resultant CaO sorbent. Steam, which can be easily separated from CO{sub 2}, has been envisioned as a potential diluent gas due to its better thermal properties resulting in effective heat transfer. A novel multi-fixed bed reactor was designed which isolates the catalyst bed from the sorbent bed during the calcination step. This should prevent any potential catalyst deactivation due to oxidation by CO{sub 2} during the regeneration phase.

  14. Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shwetha Ramkumar; Mahesh Iyer; Danny Wong; Himanshu Gupta; Bartev Sakadjian; Liang-Lhih Fan

    2008-09-30

    High purity hydrogen is commercially produced from syngas by the Water Gas Shift Reaction (WGSR) in high and low temperature shift reactors using iron oxide and copper catalysts respectively. However, the WGSR is thermodynamically limited at high temperatures towards hydrogen production necessitating excess steam addition and catalytic operation. In the calcium looping process, the equilibrium limited WGSR is driven forward by the incessant removal of CO{sub 2} by-product through the carbonation of calcium oxide. At high pressures, this process obviates the need for a catalyst and excess steam requirement, thereby removing the costs related to the procurement and deactivation of the catalyst and steam generation. Thermodynamic analysis for the combined WGS and carbonation reaction was conducted. The combined WGS and carbonation reaction was investigated at varying pressures, temperatures and S/C ratios using a bench scale reactor system. It was found that the purity of hydrogen increases with the increase in pressure and at a pressure of 300 psig, almost 100% hydrogen is produced. It was also found that at high pressures, high purity hydrogen can be produced using stoichiometric quantities of steam. On comparing the catalytic and non catalytic modes of operation in the presence of calcium oxide, it was found that there was no difference in the purity of hydrogen produced at elevated pressures. Multicyclic reaction and regeneration experiments were also conducted and it was found that the purity of hydrogen remains almost constant after a few cycles.

  15. Dependence of MgGa2O4:Co2+ photoluminescence on temperature and impurity concentration

    Science.gov (United States)

    Sosman, L. P.; Dias Tavares, A., Jr.; da Fonseca, R. J. M.; Papa, A. R. R.

    2008-10-01

    Polycrystalline samples of MgGa2O4 doped with 0.1 and 1.0% of Co2+ ions were produced by ceramic methods and investigated by x-ray diffraction and luminescence spectroscopy. Emission data at room temperature and 77 K, as well as transition lifetimes obtained by the phase-shift method, are presented. The emission is attributed to ^{4} {T}_{1}({}^{4} {P}) \\to {}^{4} {A_{2}({}{}^{4} {F})} of Co2+ ions in tetrahedral sites. The excitation spectra are associated with ^{4} {A}_{2}({}^{4} {F}) \\to {}^{2} {A}_{1}(^{2} {G}) , ^{4} {A}_{2}({}^{4} {F}) \\to {}^{2} {E}(^{2} {G}) and ^{4} {A}_{2}({}^{4} {F}) \\to {}^{4} {T}_{1}({}^{4} {P}) electronic transitions. The crystal field Dq and Racah parameter B were obtained from the spectra and Tanabe-Sugano energy level diagram. The highlights of the present work are the relatively simple sample obtention process as well as its reproducibility and the high photoluminescence quantum efficiency (near to 1.0) together with the intense and broad emission band which make the MgGa2O4 a very attractive material for use as tunable media.

  16. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

    OpenAIRE

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-01-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140?C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and ?-glucan and protein digestibility (PD)...

  17. Toluene impurity effects on CO2 separation using a hollow fiber membrane for natural gas

    KAUST Repository

    Omole, Imona C.

    2011-03-01

    The performance of defect-free cross-linkable polyimide asymmetric hollow fiber membranes was characterized using an aggressive feed stream containing up to 1000ppm toluene. The membrane was shown to be stable against toluene-induced plasticization compared with analogs made from Matrimid®, a commercial polyimide. Permeation and sorption analysis suggest that the introduction of toluene vapors in the feed subjects the membrane to antiplasticization, as the permeance decreases significantly (to less than 30%) under the most aggressive conditions tested. Separation efficiencies reflected by permselectivities were less affected. The effect of the toluene on the membrane was shown to be reversible when the toluene was removed. © 2010 Elsevier B.V.

  18. Synergistic effects of temperature extremes, hypoxia, and increases in CO2 on marine animals: From Earth history to global change

    Science.gov (United States)

    PöRtner, Hans O.; Langenbuch, Martina; Michaelidis, Basile

    2005-09-01

    Currently rising CO2 levels in atmosphere and marine surface waters as well as projected scenarios of CO2 disposal in the ocean emphasize that CO2 sensitivities need to be investigated in aquatic organisms, especially in animals which may well be the most sensitive. Moreover, to understand causes and effects, we need to identify the physiological processes that are sensitive to CO2 beyond the current emphasis on calcification. Few animals may be acutely sensitive to moderate CO2 increases, but subtle changes due to long-term exposure may already have started to be felt in a wide range of species. CO2 effects identified in invertebrate fauna from habitats characterized by oscillating CO2 levels include depressed metabolic rates and reduced ion exchange and protein synthesis rates. These result in shifts in metabolic equilibria and slowed growth. Long-term moderate hypercapnia has been observed to produce enhanced mortality with as yet unidentified cause and effect relationships. During future climate change, simultaneous shifts in temperature, CO2, and hypoxia levels will enhance sensitivity to environmental extremes relative to a change in just one of these variables. Some interactions between these variables result from joint effects on the same physiological mechanisms. Such interactions need to be considered in terms of future increases in atmospheric CO2 and its uptake by the ocean as well as in terms of currently proposed mitigation scenarios. These include purposeful injection of CO2 in the deep ocean or Fe fertilization of the surface ocean, which reduces subsurface O2 levels. The resulting ecosystem shifts could develop progressively, rather than beyond specific thresholds, such that effects parallel CO2 oscillations. It is unsure to what extent and how quickly species may adapt to permanently elevated CO2 levels by microevolutionary compensatory processes.

  19. The Contribution of Non-CO2 Greenhouse Gas Mitigation to Achieving Long-Term Temperature Goals

    Directory of Open Access Journals (Sweden)

    Ajay Gambhir

    2017-05-01

    Full Text Available This paper analyses the emissions and cost impacts of mitigation of non-CO2 greenhouse gases (GHGs at a global level, in scenarios aimed at meeting a range of long-term temperature goals (LTTGs. The study combines an integrated assessment model (TIAM-Grantham representing CO2 emissions (and their mitigation from the fossil fuel combustion and industrial sectors, coupled with a model covering non-CO2 emissions (GAINS, using the latest global warming potentials from the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. We illustrate that in general non-CO2 mitigation measures are less costly than CO2 mitigation measures, with the majority of their abatement potential achievable at US2005$100/tCO2e or less throughout the 21st century (compared to a marginal CO2 mitigation cost which is already greater than this by 2030 in the most stringent mitigation scenario. As a result, the total cumulative discounted cost over the period 2010–2100 (at a 5% discount rate of limiting global average temperature change to 2.5 °C by 2100 is $48 trillion (about 1.6% of cumulative discounted GDP over the period 2010–2100 if only CO2 from the fossil fuel and industrial sectors is targeted, whereas the cost falls to $17 trillion (0.6% of GDP by including non-CO2 GHG mitigation in the portfolio of options—a cost reduction of about 65%. The criticality of non-CO2 mitigation recommends further research, given its relatively less well-explored nature when compared to CO2 mitigation.

  20. ENHANCED HYDROGEN PRODUCTION INTEGRATED WITH CO2 SEPARATION IN A SINGLE-STAGE REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Himanshu Gupta; Mahesh Iyer; Bartev Sakadjian; Liang-Shih Fan

    2005-03-10

    The water gas shift reaction (WGSR) plays a major role in increasing the hydrogen production from fossil fuels. However, the enhanced hydrogen production is limited by thermodynamic constrains posed by equilibrium limitations of WGSR. This project aims at using a mesoporous, tailored, highly reactive calcium based sorbent system for incessantly removing the CO{sub 2} product which drives the equilibrium limited WGSR forward. In addition, a pure sequestration ready CO{sub 2} stream is produced simultaneously. A detailed project vision with the description of integration of this concept with an existing coal gasification process for hydrogen production is presented. Conceptual reactor designs for investigating the simultaneous water gas shift and the CaO carbonation reactions are presented. In addition, the options for conducting in-situ sorbent regeneration under vacuum or steam are also reported. Preliminary, water gas shift reactions using high temperature shift catalyst and without any sorbent confirmed the equilibrium limitation beyond 600 C demonstrating a carbon monoxide conversion of about 80%. From detailed thermodynamic analyses performed for fuel gas streams from typical gasifiers the optimal operating temperature range to prevent CaO hydration and to effect its carbonation is between 575-830 C.

  1. 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.

  2. Spatial and Seasonal Variability of Temperature in CO2 Emission from Mars' Mesosphere

    Science.gov (United States)

    Livengood, Timothy A.; Kostiuk, Theodor; Hewagama, Tilak; Kolasinski, John R.; Henning, Wade; Fast, Kelly Elizabeth; Sonnabend, Guido; Sornig, Manuela

    2017-10-01

    We have observed non-local thermodynamic equilibrium (non-LTE) emission of carbon dioxide that probes Mars’ mesosphere in 2001, 2003, 2007, 2012, 2014, and 2016. These measurements were conducted at 10.6 μm wavelength using the Goddard Space Flight Center Heterodyne Instrument for Planetary Winds and Composition (HIPWAC) from the NASA Infrared Telescope Facility (IRTF) at resolving power (1-33)×106. The Maxwellian broadening of the emission line can be measured at this resolution, providing a direct determination of temperature in the mesosphere. The nonLTE line appears as a narrow emission core within a broad absorption formed by tropospheric CO2, which provides temperature information reaching down to the martian surface, while the mesospheric line probes temperature at about 60-80 km altitude. We will report on the spatial distribution of temperature and emission line strength with local solar time on Mars, with latitude, as well as long-term variability including seasonal effects that modify the overall thermal structure of the atmosphere. These remote measurements complement results from orbital spacecraft through access to a broad range of local solar time on each occasion.This work has been supported by the NASA Planetary Astronomy and Solar Systems Observations Programs

  3. Ab initio molecular dynamics study of fluid H2O-CO2 mixture in broad pressure-temperature range

    Science.gov (United States)

    Fu, Jie; Zhao, Jijun; Plyasunov, Andrey V.; Belonoshko, Anatoly B.

    2017-11-01

    Properties of H2O and CO2 fluid and their mixtures under extreme pressures and temperatures are poorly known yet critically important in a number of applications. Several hundreds of first-principles molecular dynamics (FPMD) runs have been performed to obtain the pressure-volume-temperature (P-V-T) data on supercritical H2O, CO2, and H2O-CO2 mixtures. The pressure-temperature (P-T) range are from 0.5 GPa to 104 GPa (48.5 GPa for CO2) and from 600 K to 4000 K. Based on these data, we evaluate several existing equations of state (EOS) for the fluid H2O, CO2, and H2O-CO2 mixture. The results show that the EOS for H2O from Belonoshko et al. [Geochim. Cosmochim. Acta 55, 381-387; Geochim. Cosmochim. Acta 55, 3191-3208; Geochim. Cosmochim. Acta 56, 3611-3626; Comput. Geosci. 18, 1267-1269] not only can be used in the studied P-T range but also is accurate enough to be used for prediction of P-V-T data. In addition, IAPWS-95 EOS for H2O shows excellent extrapolation behavior beyond 1.0 GPa and 1273 K. However, for the case of CO2, none of the existing EOS produces data in agreement with the FPMD results. We created new EOS for CO2. The precision of the new EOS is tested by comparison to the calculated P-V-T data, fugacity coefficient of the CO2 fluid derived from high P-T experimental data as well as to the (very scarce) experimental volumetric data in the high P-T range. On the basis of our FPMD data we created a new EOS for H2O-CO2 mixture. The new EOS for the mixture is in reasonable agreement with experimental data.

  4. Do all leaf photosynthesis parameters of rice acclimate to elevated CO2, elevated temperature, and their combination, in FACE environments?

    Science.gov (United States)

    Cai, Chuang; Li, Gang; Yang, Hailong; Yang, Jiaheng; Liu, Hong; Struik, Paul C; Luo, Weihong; Yin, Xinyou; Di, Lijun; Guo, Xuanhe; Jiang, Wenyu; Si, Chuanfei; Pan, Genxing; Zhu, Jianguo

    2018-04-01

    Leaf photosynthesis of crops acclimates to elevated CO 2 and temperature, but studies quantifying responses of leaf photosynthetic parameters to combined CO 2 and temperature increases under field conditions are scarce. We measured leaf photosynthesis of rice cultivars Changyou 5 and Nanjing 9108 grown in two free-air CO 2 enrichment (FACE) systems, respectively, installed in paddy fields. Each FACE system had four combinations of two levels of CO 2 (ambient and enriched) and two levels of canopy temperature (no warming and warmed by 1.0-2.0°C). Parameters of the C 3 photosynthesis model of Farquhar, von Caemmerer and Berry (the FvCB model), and of a stomatal conductance (g s ) model were estimated for the four conditions. Most photosynthetic parameters acclimated to elevated CO 2 , elevated temperature, and their combination. The combination of elevated CO 2 and temperature changed the functional relationships between biochemical parameters and leaf nitrogen content for Changyou 5. The g s model significantly underestimated g s under the combination of elevated CO 2 and temperature by 19% for Changyou 5 and by 10% for Nanjing 9108 if no acclimation was assumed. However, our further analysis applying the coupled g s -FvCB model to an independent, previously published FACE experiment showed that including such an acclimation response of g s hardly improved prediction of leaf photosynthesis under the four combinations of CO 2 and temperature. Therefore, the typical procedure that crop models using the FvCB and g s models are parameterized from plants grown under current ambient conditions may not result in critical errors in projecting productivity of paddy rice under future global change. © 2017 John Wiley & Sons Ltd.

  5. Does long-term cultivation of saplings under elevated CO2 concentration influence their photosynthetic response to temperature?

    Science.gov (United States)

    Šigut, Ladislav; Holišová, Petra; Klem, Karel; Šprtová, Mirka; Calfapietra, Carlo; Marek, Michal V.; Špunda, Vladimír; Urban, Otmar

    2015-01-01

    Background and Aims Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature optima of photosynthetic processes will shift towards higher temperatures and the thermostability of the photosynthetic apparatus will increase. Methods The hypothesis was tested for saplings of broadleaved Fagus sylvatica and coniferous Picea abies exposed for 4–5 years to either ambient (AC; 385 µmol mol−1) or elevated (EC; 700 µmol mol−1) CO2 concentrations. Temperature response curves of photosynthetic processes were determined by gas-exchange and chlorophyll fluorescence techniques. Key Results Initial assumptions of reduced light-saturated stomatal conductance and increased leaf temperatures for EC plants were confirmed. Temperature response curves revealed stimulation of light-saturated rates of CO2 assimilation (Amax) and a decline in photorespiration (RL) as a result of EC within a wide temperature range. However, these effects were negligible or reduced at low and high temperatures. Higher temperature optima (Topt) of Amax, Rubisco carboxylation rates (VCmax) and RL were found for EC saplings compared with AC saplings. However, the shifts in Topt of Amax were instantaneous, and disappeared when measured at identical CO2 concentrations. Higher values of Topt at elevated CO2 were attributed particularly to reduced photorespiration and prevailing limitation of photosynthesis by ribulose-1,5-bisphosphate (RuBP) regeneration. Temperature response curves of fluorescence parameters suggested a negligible effect of EC on enhancement of thermostability of photosystem II photochemistry. Conclusions Elevated CO2 instantaneously increases temperature optima of Amax due to reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, this increase disappears when plants

  6. Room temperature CO2 gas sensors of AuNPs/mesoPSi hybrid structures

    Science.gov (United States)

    Alwan, Alwan M.; Dheyab, Amer B.

    2017-10-01

    Mesoporous silicon (mesoPSi) layer prepared by a laser-assisted etching process in HF acid has been employed as CO2 gas sensors. The surface morphology of mesoPSi was modified by embedding gold nanoparticles AuNPs by simple and quick dipping process in different gold salts concentrations to form mesoPSi/AuNPs hybrid structures. Morphology of hybrid structures was investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrical characteristics of the prepared gas sensor were carried out at room temperature. It was found that the nanoparticles size, shape and the specific surface area of the nanoparticle strongly influence the current-voltage characteristics. Considerable improvement was noticed in sensitivity, response and recovery times of gas sensor with decreasing incorporated AuNPs into the mesoPSi matrix.

  7. Effect of diurnal and seasonal temperature variation on Cussac cave ventilation using co2 assessment

    Science.gov (United States)

    Peyraube, Nicolas; Lastennet, Roland; Villanueva, Jessica Denila; Houillon, Nicolas; Malaurent, Philippe; Denis, Alain

    2017-08-01

    Cussac cave was investigated to assess the cave air temperature variations and to understand its ventilation regime. This cave is located in an active karst system in the south west part of France. It has a single entrance and is considered as a cold air trap. In this study, air mass exchanges were probed. Measurements of temperature and Pco2 with a 30-min frequency were made in several locations close to the cave entrance. Speed of the air flow was also measured at the door of cave entrance. Results show that cave air Pco2 varies from 0.18 to 3.33 %. This cave appears to be a CO2 source with a net mass of 2319 tons blown in 2009. Carbon-stable isotope of CO2 (13Cco2) ranges from -20.6 ‰ in cold season to -23.8 ‰ in warm season. Cave air is interpreted as a result of a mix between external air and an isotopically depleted air, coming from the rock environment. The isotopic value of the light member varies through time, from -23.9 to -22.5 ‰. Furthermore, this study ascertains that the cave never stops in communicating with the external air. The ventilation regime is identified. (1) In cold season, the cave inhales at night and blows a little at the warmest hours. However, in warm season, (2) cave blows at night, but (3) during the day, a convection loop takes place in the entrance area and prevents the external air from entering the cave, confirming the cold air trap.

  8. Experimental Evidence for High-Pressure Phase Separation in the H2O-CO2-CaCl2 System: Implications for Rock Rheology

    Science.gov (United States)

    Selverstone, J.; Chernak, L.; Tullis, J.; Cooper, R.

    2007-12-01

    As part of a study to examine the effect of CO2 on deformation mechanisms in quartz, axial compression experiments were carried out at 900°C and 1500 MPa on cores of Black Hills quartzite (BHQ) with a layer of dolomite powder (± 0.05 wt% H2O) in the center of each charge (some runs included buffer assemblages at sample ends). All runs released CO2 via the reaction dol + qtz = diop + CO2 during run-up to experimental conditions. BHQ starting material contains three types of naturally occurring fluid inclusions (FIs): pure H2O, H2O + 6-18 wt% CaCl2, and pure CO2. Deformation experiments on as-is BHQ (no dol powder) result in destruction of most optical FIs. In contrast, experiments with wet dol powder produced visible FIs in nearly all samples, though most were too small to analyze by microthermometry. One hydrostatic experiment with dolomite generated FIs up to 15 microns across near the reaction zone. FIs within this sample fall into two types: (1) superdense CO2 (homogenization to liquid below -50°C), and (2) H2O-CO2-CaCl2 solutions with variable X(CO2) and bulk density and up to 40 wt% CaCl2 (referenced to aqueous phase only). Both inclusion types occur within the same clusters, and likely result from interaction of CO2 released by dol breakdown with H2O and FI fluids released from the starting material. Isochores from the Type 1 CO2 FIs record pressures of 1200- 1400 MPa at 900°C. Estimation of bulk density for Type 2 FIs is hampered by complex microthermometric behavior and incomplete equation of state data for this fluid system, but model isochores overlap with those of Type 1 FIs at 900°C. Entrapment of the two types of FIs and variable phase proportions in Type 2 inclusions are consistent with fluid phase separation at experimental conditions. Deformation experiments run at f(O2)field and result in an increase in both a(H2O) and f(H2O), which in turn will facilitate strain accommodation by dislocation and/or diffusion creep. Shmulovich & Graham (2004

  9. Evidence that higher [CO2] increases tree growth sensitivity to temperature: a comparison of modern and paleo oaks

    Science.gov (United States)

    Steven L. Voelker; Michael C. Stambaugh; J. Renée Brooks; Frederick C. Meinzer; Barbara Lachenbruch; Richard P. Guyette

    2017-01-01

    To test tree growth-sensitivity to temperature under different ambient CO2 concentrations, we determined stem radial growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatial variation in temperature across the modern species distributional...

  10. Accelerated Carbonate Dissolution as a CO2 Separation and Sequestration Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Caldeira, K G; Knauss, K G; Rau, G H

    2004-02-18

    We have proposed a technique that could reduce CO{sub 2} emissions from near coastal fossil-fuel power plants using existing power plant cooling water flow rates (Rau and Caldeira, 1999; Caldeira and Rau, 2000). Preliminary cost estimates are as low as $68 per tonne C sequestered, as compared to > $170 per tonne C estimated for other approaches to CO{sub 2} separation with geologic or deep-ocean storage. Engineers at McDermott Technologies, Inc., have independently estimated the cost of our proposed technique, and came to the conclusion that our cost estimates were at the high end of the likely range. Interest has been expressed in pursuing this approach further both in Norway and in Japan. We have proved the viability of our concept using (1) bench-top laboratory experiments (Figures 1 and 2), (2) computer modeling of those experiments, (3) more sophisticated cost estimates, and (4) three-dimensional computer modeling of the consequences to global ocean chemistry (Figure 3 and 4). The climate and environmental impacts of our current, carbon intensive energy usage demands that effective and practical energy alternatives and CO{sub 2} mitigation strategies be found. As part of this effort, various means of capturing and storing CO{sub 2} generated from fossil-fuel-based energy production are being investigated (e.g. [3,4]). One of the proposed methods involves a geochemistry-based capture and sequestration process [5,6] that hydrates point-source, waste CO{sub 2} with water to produce a carbonic acid solution. This in turn is reacted and neutralized with limestone, thus converting the original CO{sub 2} gas to calcium bicarbonate in solution, the overall reaction being: CO{sub 2(g)} + H{sub 2}O{sub (l)} + CaCO{sub 3(s)} {yields} Ca{sub (aq)}{sup 2+} + 2HCO{sub 3(aq)}{sup -} The dissolved calcium bicarbonate produced is then released and diluted in the ocean where it would add minimally to the large, benign pool of these ions already present in seawater. Such a

  11. Growth performance and survival of larval Atlantic herring, under the combined effects of elevated temperatures and CO2.

    Directory of Open Access Journals (Sweden)

    Michael Sswat

    Full Text Available In the coming decades, environmental change like warming and acidification will affect life in the ocean. While data on single stressor effects on fish are accumulating rapidly, we still know relatively little about interactive effects of multiple drivers. Of particular concern in this context are the early life stages of fish, for which direct effects of increased CO2 on growth and development have been observed. Whether these effects are further modified by elevated temperature was investigated here for the larvae of Atlantic herring (Clupea harengus, a commercially important fish species. Over a period of 32 days, larval survival, growth in size and weight, and instantaneous growth rate were assessed in a crossed experimental design of two temperatures (10°C and 12°C with two CO2 levels (400 μatm and 900 μatm CO2 at food levels mimicking natural levels using natural prey. Elevated temperature alone led to increased swimming activity, as well as decreased survival and instantaneous growth rate (Gi. The comparatively high sensitivity to elevated temperature in this study may have been influenced by low food levels offered to the larvae. Larval size, Gi and swimming activity were not affected by CO2, indicating tolerance of this species to projected "end of the century" CO2 levels. A synergistic effect of elevated temperature and CO2 was found for larval weight, where no effect of elevated CO2 concentrations was detected in the 12°C treatment, but a negative CO2 effect was found in the 10°C treatment. Contrasting CO2 effects were found for survival between the two temperatures. Under ambient CO2 conditions survival was increased at 12°C compared to 10°C. In general, CO2 effects were minor and considered negligible compared to the effect of temperature under these mimicked natural food conditions. These findings emphasize the need to include biotic factors such as energy supply via prey availability in future studies on interactive

  12. Oxygen and carbon isotope fractionation in the system dolomite-water-CO2 to elevated temperatures

    Science.gov (United States)

    Horita, Juske

    2014-03-01

    An experimental study was conducted to determine oxygen and carbon isotope fractionation factors in the system dolomite-water-CO2 at 80-350 and 100-250 °C, respectively, by means of direct precipitation (80 °C) and dolomitization of CaCO3 (100-350 °C). The products are protodolomite with slight Ca-excess (80-100 °C) and well-ordered stoichiometric dolomite (150-350 °C). Several experimental artifacts (inheritance, premature reactions, and kinetic effects) were tested, although attainment of isotope equilibrium cannot be proven. 18O/16O fractionation factors of (proto)dolomite-water at 80-350 °C can be readily expressed with 1σ error: 103lnα=3.140(±0.022)·{106}/{T2}-3.14(±0.11). Our experimental study, which is generally consistent with a majority of experimental and theoretical studies in the literature, provides for the first time an accurate equation over a wide range of temperature. In combination of the calcite-water equation (O’Neil et al., 1969; Friedman and O’Neil, 1977), 18O/16O fractionation factors of (proto)dolomite-calcite at 80-350 °C can also be expressed with 1σ error: 103lnα=0.351(±0.028)·{106}/{T2}-0.25(±0.13). Dolomite is slightly (0.7-2.6‰) enriched in 18O relative to calcite in this temperature range. Given the very good linearity with a 1/T2 term, the above two equations may be extrapolated beyond the temperature range. Our experimental results of 13C/12C fractionation between CO2 and dolomite at 100-250 °C also show a linear function with a 1/T2 term with a cross-over temperature of 200 °C, which differs from results of theoretical calculations.

  13. Combined effects of elevated temperature and CO2 concentration on Cd and Zn accumulation dynamics in Triticum aestivum L.

    Science.gov (United States)

    Wang, Xiaoheng; Li, Yu; Lu, Hong; Wang, Shigong

    2016-09-01

    A simulated climate warming experiment was conducted to evaluate the combined effects of elevated temperature and CO2 concentration on the bioaccumulation, translocation and subcellular distributions of Cd and Zn in wheat seedlings (Triticum aestivum L. cv. Xihan 1.) at Dingxi, Gansu Province, China. The objective was to find evidence that global climate change is affecting the bioaccumulation of Cd and Zn in T. aestivum L. cv. Xihan 1. The results showed that compared to control A, elevated temperature and CO2 increased Cd bioaccumulation in the shoots by 1.4-2.5 times, and increased that in the roots by 1.2-1.5 times, but decreased Zn levels in wheat shoots by 1.4-2.0 times, while decreased that in the roots by 1.6-1.9 times. Moreover, temperature and CO2 concentration increase also led to increased Cd concentration, and decreased Zn concentration in subcellular compartments of wheat seedlings. The largest Cd concentration increase (174.4%) was observed in the cell wall and debris fractions of shoots after they were subjected to the highest CO2 and temperature treatment (TC3). The largest Zn concentration decrease (53.1%) was observed in the soluble (F3) fractions of shoots after they were subjected to the medium CO2 and temperature treatment (TC2). The temperature and CO2 increase had no significant effect on the proportional distribution of Cd and Zn in the subcellular fractions. The root-to-shoot translocation of Cd increased with the increasing temperature and CO2 concentration. However, the Zn distributions only fluctuated within a small range. Copyright © 2016. Published by Elsevier B.V.

  14. A novel rate of the reaction between NaOH with CO2 at low temperature in spray dryer

    Directory of Open Access Journals (Sweden)

    Yadollah Tavan

    2017-03-01

    Full Text Available Carbon dioxide (CO2 is an influential greenhouse gas that has a significant impact on global warming partly. Nowadays, many techniques are available to control and remove CO2 in different chemical processes. Since the spray dryer has high removal efficiency rate, a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH. In the present study, the impact of NaOH concentration, operating temperature and nozzle diameter on removal efficiency of CO2 is explored through experimental study. Moreover, the reaction kinetic of NaOH with CO2 is studied over the temperature range of 50–100 °C in a laboratory-scale spray dryer absorber. In the present contribution, a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.

  15. Effect of water and temperature on absorption of CO2 by amine-functionalized anion-tethered ionic liquids.

    Science.gov (United States)

    Goodrich, Brett F; de la Fuente, Juan C; Gurkan, Burcu E; Lopez, Zulema K; Price, Erica A; Huang, Yong; Brennecke, Joan F

    2011-07-28

    Amine-functionalized anion-tethered ionic liquids (ILs) trihexyl(tetradecyl)phosphonium asparaginate [P(66614)][Asn], glutaminate [P(66614)][Gln], lysinate [P(66614)][Lys], methioninate [P(66614)][Met], prolinate [P(66614)][Pro], taurinate [P(66614)][Tau], and threoninate [P(66614)][Thr] were synthesized and investigated as potential absorbents for CO(2) capture from postcombustion flue gas. Their physical properties, including density, viscosity, glass transition temperature, and thermal decomposition temperature were determined. Furthermore, the CO(2) absorption isotherms of [P(66614)][Lys], [P(66614)][Tau], [P(66614)][Pro], and [P(66614)][Met] were measured using a volumetric method, and the results were modeled with two different Langmuir-type absorption models. The most important result of this study is that the viscosity of [P(66614)][Pro] only increased by a factor of 2 when fully complexed with 1 bar of CO(2) at room temperature. This is in stark contrast to the other chemically reacted ILs investigated here and all other amino acid-based ILs reported in the literature, which dramatically increase in viscosity, typically by 2 orders of magnitude, when complexed with CO(2). The unique behavior of [P(66614)][Pro] is likely due to its ring structure, which limits the number and availability of hydrogen atoms that can participate in a hydrogen bonding network. We found that water can be used to further reduce the viscosity of the CO(2)-complexed IL, while only slightly decreasing the CO(2) capacity. Finally, from temperature-dependent isotherms, we estimate a heat of absorption of -63 kJ/mol of CO(2) for the 1:1 reaction of CO(2) with [P(66614)][Pro], when we use the two-reaction model. © 2011 American Chemical Society

  16. Monitoring gaseous CO2 and ethanol above champagne glasses: flute versus coupe, and the role of temperature.

    Directory of Open Access Journals (Sweden)

    Gérard Liger-Belair

    Full Text Available In champagne tasting, gaseous CO(2 and volatile organic compounds progressively invade the headspace above glasses, thus progressively modifying the chemical space perceived by the consumer. Simultaneous quantification of gaseous CO(2 and ethanol was monitored through micro-gas chromatography (μGC, all along the first 15 minutes following pouring, depending on whether a volume of 100 mL of champagne was served into a flute or into a coupe. The concentration of gaseous CO(2 was found to be significantly higher above the flute than above the coupe. Moreover, a recently developed gaseous CO(2 visualization technique based on infrared imaging was performed, thus confirming this tendency. The influence of champagne temperature was also tested. As could have been expected, lowering the temperature of champagne was found to decrease ethanol vapor concentrations in the headspace of a glass. Nevertheless, and quite surprisingly, this temperature decrease had no impact on the level of gaseous CO(2 found above the glass. Those results were discussed on the basis of a multiparameter model which describes fluxes of gaseous CO(2 escaping the liquid phase into the form of bubbles.

  17. Effects of temperature, pH, water activity and CO2 concentration on growth of Rhizopus oligosporus NRRL 2710.

    Science.gov (United States)

    Sparringa, R A; Kendall, M; Westby, A; Owens, J D

    2002-01-01

    To investigate the effects of temperature, pH, water activity (aw) and CO2 concentration on the growth of Rhizopus oligosporus NRRL 2710. Hyphal extension rates from mycelial and spore inocula were measured on media with different aw (approximately 1.0, 0.98 and 0.96) and pH (3.5, 5.5 and 7.5) incubated at 30, 37 or 42 degrees C in atmospheres containing 0.03, 12.5 or 25% (v/v) CO2. The effects of environmental conditions on hyphal extension rate were modelled using surface response methodology. The rate of hyphal extension was very sensitive to pH, exhibiting a pronounced optimum at pH 5.5-5.8. The hyphal extension rate was less sensitive to temperature, aw or CO2, exhibiting maximum rates at 42 degrees C, a(w) approximately 1.0 and 0.03% (v/v) CO2. The fastest hyphal extension rate (1.7 mm h(-1)) was predicted to occur at 42 degrees C, pH 5.85, a(w) approximately 1.0 and 0.03% CO2. The present work is the first to model the simultaneous effects of temperature, pH, aw and CO2 concentration on mould growth. The information relates to tempe fermentation and to possible control of the microflora in Tanzanian cassava heap fermentations.

  18. Monitoring gaseous CO2 and ethanol above champagne glasses: flute versus coupe, and the role of temperature.

    Science.gov (United States)

    Liger-Belair, Gérard; Bourget, Marielle; Pron, Hervé; Polidori, Guillaume; Cilindre, Clara

    2012-01-01

    In champagne tasting, gaseous CO(2) and volatile organic compounds progressively invade the headspace above glasses, thus progressively modifying the chemical space perceived by the consumer. Simultaneous quantification of gaseous CO(2) and ethanol was monitored through micro-gas chromatography (μGC), all along the first 15 minutes following pouring, depending on whether a volume of 100 mL of champagne was served into a flute or into a coupe. The concentration of gaseous CO(2) was found to be significantly higher above the flute than above the coupe. Moreover, a recently developed gaseous CO(2) visualization technique based on infrared imaging was performed, thus confirming this tendency. The influence of champagne temperature was also tested. As could have been expected, lowering the temperature of champagne was found to decrease ethanol vapor concentrations in the headspace of a glass. Nevertheless, and quite surprisingly, this temperature decrease had no impact on the level of gaseous CO(2) found above the glass. Those results were discussed on the basis of a multiparameter model which describes fluxes of gaseous CO(2) escaping the liquid phase into the form of bubbles.

  19. Plant nutrient mobilization in temperate heathland responds to elevated CO2, temperature and drought

    DEFF Research Database (Denmark)

    Andresen, Louise C.; Michelsen, Anders; Jonasson, Sven

    2010-01-01

    when combined with CO2 and drought. Below Deschampsia, the net nitrification rate decreased in response to drought and, while phosphorus availability and microbial P immobilization decreased, but nitrification increased in response to elevated CO2. Furthermore, leaf litter decomposition of both species...

  20. Evidence that higher CO2 increases tree growth sensitivity to temperature: a comparison of modern and paleo oaks

    Science.gov (United States)

    Aim: To test the growth-sensitivity to temperature under different ambient CO2 concentrations, we determined paleo tree growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatia...

  1. Effects of Changes in Temperature and CO2 Concentration on Simulated Spring Wheat Yields in The Netherlands

    NARCIS (Netherlands)

    Nonhebel, Sanderine

    1993-01-01

    A crop growth simulation model based on SUCROS87 was constructed to study the effects of temperature rise and increase of the atmospheric CO2 concentration on spring wheat yields in The Netherlands. The model simulated potential production (limited by crop characteristics, temperature and radiation

  2. Competition between cheatgrass and bluebunch wheatgrass is altered by temperature, resource availability, and atmospheric CO2 concentration.

    Science.gov (United States)

    Larson, Christian D; Lehnhoff, Erik A; Noffsinger, Chance; Rew, Lisa J

    2017-12-22

    Global change drivers (elevated atmospheric CO2, rising surface temperatures, and changes in resource availability) have significant consequences for global plant communities. In the northern sagebrush steppe of North America, the invasive annual grass Bromus tectorum (cheatgrass) is expected to benefit from projected warmer and drier conditions, as well as increased CO2 and nutrient availability. In growth chambers, we addressed this expectation using two replacement series experiments designed to test competition between B. tectorum and the native perennial bunchgrass Pseudoroegneria spicata. In the first experiment, we tested the effects of elevated temperature, decreased water and increased nutrient availability, on competition between the two species. In the second, we tested the effects of elevated atmospheric CO2 and decreased water availability on the competitive dynamic. In both experiments, under all conditions, P. spicata suppressed B. tectorum, though, in experiment one, warmer and drier conditions and elevated nutrient availability increased B. tectorum's competitiveness. In experiment two, when grown in monoculture, both species responded positively to elevated CO2. However, when grown in competition, elevated CO2 increased P. spicata's suppressive effect, and the combination of dry soil conditions and elevated CO2 enhanced this effect. Our findings demonstrate that B. tectorum competitiveness with P. spicata responds differently to global change drivers; thus, future conditions are unlikely to facilitate B. tectorum invasion into established P. spicata communities of the northern sagebrush steppe. However, disturbance (e.g., fire) to these communities, and the associated increase in soil nutrients, elevates the risk of B. tectorum invasion.

  3. 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.

  4. 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.

  5. Facile preparation of ordered mesoporous MnCo2O4 for low-temperature selective catalytic reduction of NO with NH3

    Science.gov (United States)

    Qiu, Mingying; Zhan, Sihui; Yu, Hongbing; Zhu, Dandan; Wang, Shengqiang

    2015-01-01

    Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale.Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale. Electronic supplementary information (ESI) available: Low-angle XRD

  6. Temperature versus plant effects on diel dynamics of soil CO2 production and efflux: a controlled environment study

    Science.gov (United States)

    Reinthaler, David; Roy, Jacques; Landais, Damien; Piel, Clement; Resco de Dios, Victor; Bahn, Michael

    2015-04-01

    Soil respiration (Rs) is the biggest source of CO2 emitted from terrestrial ecosystems to the atmosphere. Therefore the understanding of its drivers is of major importance for models of carbon cycling. Next to temperature as a major abiotic factor, photosynthesis has been suggested as an important driver influencing diel patterns in Rs. Under natural conditions it is difficult to disentangle abiotic and biotic effects on soil CO2 production, as fluctuating light intensity affects both photosynthetic activity and soil temperature. To analyse individual and combined effects of soil temperature and light on the dynamics of soil CO2 production and efflux, we performed a controlled environment study at the ECOTRON facility in Montpellier. The study manipulated temperature and photosynthetically active radiation independently and was carried out in large macrocosms, hosting canopies of either a woody (cotton) or a herbaceous (bean) crop. In each macrocosm membrane tubes had been installed across the soil profile for continuous measurement of soil CO2 concentrations. In addition, an automated soil respiration system was installed in each macrocosm, whose data were also used for validating a model of soil CO2 production and transport based on the concentration profiles. Both for cotton and for bean canopies, under conditions of naturally fluctuating temperature and light conditions, soil CO2 production and efflux followed a clear diel pattern. Under constantly dark conditions (excluding immediate effects of photosynthesis) and constant temperature, no significant diel changes in Rs could be observed. Furthermore, soil CO2 production and efflux did not increase significantly upon exposure of previously darkened macrocosms to light. Under constant temperature and fluctuating light conditions, we observed a dampened diel pattern of Rs, which did not match diurnal solar cycles. A detailed residual analysis accounting for temporal trends in soil moisture suggested a significant

  7. Combined effects of CO2 enrichment and elevated growth temperatures on metabolites in soybean leaflets; evidence for dynamic changes of TCA cycle intermediates

    Science.gov (United States)

    Soybean (Glycine max [Merr.]L.) was grown in indoor chambers with ambient (38 Pa) and elevated (70 Pa) CO2 and day/night temperature treatments of 28/20, 32/24, and 36/28 °C. Net rates of CO2 assimilation increased with growth temperature and were enhanced an additional 25% on average by CO2 enrich...

  8. Sensitivity of temperate grassland species to elevated atmospheric CO2 and the interaction with temperature and water stress

    Directory of Open Access Journals (Sweden)

    M.B. JONES

    2008-12-01

    Full Text Available The annual cycle of growth of many temperate grasses is limited by low temperatures during the winter and spring and water stress during the summer. Climate change, induced by increase in the concentration of greenhouse gases in the atmosphere, can affect the growth and community structure of temperate grasslands in two ways. The first is directly through changes in atmospheric concentration of CO2 and the second is indirectly through changes in temperature and rainfall. At higher latitudes, where growth is largely temperature limited, it is probable that the direct effects of enhanced CO2 will be less than at low latitudes. However, interactions with increasing temperature and water stress are complex. Temperate grasslands range from intensively managed monocultures of sown species to speciesrich natural and semi-natural communities whose local distributions are controlled by variations in soil type and drainage. The different species can show marked differences in their responses to increasing CO2 concentrations, rising temperatures and water stress. This will probably result in major alterations in the community structure of temperate grasslands in the future. In addition to impacts on primary productivity and community structure, a long-term effect of elevated CO2 on grasslands is likely to be a significant increase in soil carbon storage. However, this may be counteracted by increases in temperature.;

  9. 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

  10. Metabolic Heat Regenerated Temperature Swing Adsorption for CO2, Thermal and Humidity Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MTSA technology specifically addresses the thermal, CO2 and humidity control challenges faced by Portable Life Support Systems (PLSS) to be used in NASA's...

  11. 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.

  12. Metabolic Heat Regenerated Temperature Swing Adsorption for CO2 and Heat Removal/Rejection in a Martian PLSS

    Science.gov (United States)

    Iacomini, Christine; Powers, Aaron; Bower, Chad; Straub-Lopez, Kathrine; Anderson, Grant; MacCallum, Taber; Paul, Heather L.

    2007-01-01

    Two of the fundamental problems facing the development of a Portable Life Support System (PLSS) for use on Mars, are (i) heat rejection (because traditional technologies use sublimation of water, which wastes a scarce resource and contaminates the premises), and (ii) rejection of carbon dioxide (CO2) in an environment with a CO2 partial pressure (ppCO2) of 0.4-0.9 kPa. Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed to address both these challenges. The technology utilizes an adsorbent that when cooled with liquid CO2 to near sublimation temperatures (195K) removes metabolically-produced CO2 in the ventilation loop. Once fully loaded, the adsorbent is then warmed externally by the ventilation loop (300K), rejecting the captured CO2 to Mars ambient. Two beds are used to provide a continuous cycle of CO2 removal/rejection as well as facilitate heat exchange out of the ventilation loop. Any cryogenic fluid can be used in the application; however, since CO2 is readily available on Mars and can be easily produced and stored on the Martian surface, the solution is rather elegant and less complicated when employing liquid CO2. As some metabolic heat will need to be rejected anyway, finding a practical use for metabolic heat is also an overall benefit to the PLSS. To investigate the feasibility of the technology, a series of experiments were conducted which lead to the selection and partial characterization of an appropriate adsorbent. The Molsiv Adsorbents 13X 8x12 (also known as NaX zeolite) successfully removed CO2 from a simulated ventilation loop at the prescribed temperature swing anticipated during PLSS operating conditions on Mars using a cryogenic fluid. Thermal conductivity of the adsorbent was also measured to eventually aid in a demonstrator design of the technology. These results provide no show stoppers to the development of MTSA technology and allow its development to focus on other design

  13. Simple additive effects are rare: a quantitative review of plant biomass and soil process responses to combined manipulations of CO2 and temperature

    NARCIS (Netherlands)

    Dieleman, W.; Vicca, S.; Dijkstra, F.A.; Hoosbeek, M.R.

    2012-01-01

    In recent years, increased awareness of the potential interactions between rising atmospheric CO2 concentrations ([ CO2 ]) and temperature has illustrated the importance of multifactorial ecosystem manipulation experiments for validating Earth System models. To address the urgent need for increased

  14. Geological Sequestration Training and Research Program in Capture and Transport: Development of the Most Economical Separation Method for CO2 Capture

    Energy Technology Data Exchange (ETDEWEB)

    Vahdat, Nader

    2013-09-30

    The project provided hands-on training and networking opportunities to undergraduate students in the area of carbon dioxide (CO2) capture and transport, through fundamental research study focused on advanced separation methods that can be applied to the capture of CO2 resulting from the combustion of fossil-fuels for power generation . The project team’s approach to achieve its objectives was to leverage existing Carbon Capture and Storage (CCS) course materials and teaching methods to create and implement an annual CCS short course for the Tuskegee University community; conduct a survey of CO2 separation and capture methods; utilize data to verify and develop computer models for CO2 capture and build CCS networks and hands-on training experiences. The objectives accomplished as a result of this project were: (1) A comprehensive survey of CO2 capture methods was conducted and mathematical models were developed to compare the potential economics of the different methods based on the total cost per year per unit of CO2 avoidance; and (2) Training was provided to introduce the latest CO2 capture technologies and deployment issues to the university community.

  15. A Study on the Applicability of Kinetic Models for Shenfu Coal Char Gasification with CO2 at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Jinsheng Gao

    2009-07-01

    Full Text Available In this paper, measurements of the CO2 gasification kinetics for two types of Shenfu coal chars, which were respectively prepared by slow and rapid pyrolysis at temperatures of 950 °C and 1,400 °C, were performed by an isothermal thermo-gravimetric analysis under ambient pressure and elevated temperature conditions. Simultaneously, the applicability of the kinetic model for the CO2 gasification reaction of Shenfu coal chars was discussed. The results showed: (i the shrinking un-reacted core model was not appropriate to describe the gasification reaction process of Shenfu coal chars with CO2 in the whole experimental temperature range; (ii at the relatively low temperatures, the modified volumetric model was as good as the random pore model to simulate the CO2 gasification reaction of Shenfu coal chars, while at the elevated temperatures, the modified volumetric model was superior to the random pore model for this process; (iii the integral expression of the modified volumetric model was more favorable than the differential expression of that for fitting the experimental data. Moreover, by simply introducing a function: A = A★exp(ft, it was found that the extensive model of the modified volumetric model could make much better predictions than the modified volumetric model. It was recommended as a convenient empirical model for comprehensive simulation of Shenfu coal char gasification with under conditions close to those of entrained flow gasification.

  16. Characterization of an urban-rural CO 2 /temperature gradient and associated changes in initial plant productivity during secondary succession

    Energy Technology Data Exchange (ETDEWEB)

    Ziska, L. H.; Bunce, J. A.; Goins, E. W.

    2004-05-01

    To examine the impact of climate change on vegetative productivity, we exposed fallow agricultural soil to an in situ temperature and CO2 gradient between urban, suburban and rural areas in 2002. Along the gradient, average daytime CO2 concentration increased by 21% and maximum (daytime) and minimum (nighttime) daily temperatures increased by 1.6 and 3.3°C, respectively in an urban relative to a rural location. Consistent location differences in soil temperature were also ascertained. No other consistent differences in meteorological variables (e.g. wind speed, humidity, PAR, tropospheric ozone) as a function of urbanization were documented. The urban-induced environmental changes that were observed were consistent with most short-term (~50 year) global change scenarios regarding CO2 concentration and air temperature. Productivity, determined as final above-ground biomass, and maximum plant height were positively affected by daytime and soil temperatures as well as enhanced [CO2], increasing 60 and 115% for the suburban and urban sites, respectively, relative to the rural site. While long-term data are needed, these initial results suggest that urban environments may act as a reasonable surrogate for investigating future climatic change in vegetative communities.

  17. 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...

  18. 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.

  19. Links between iron supply, marine productivity, sea surface temperature, and CO2 over the last 1.1 Ma

    Science.gov (United States)

    MartíNez-Garcia, Alfredo; Rosell-Melé, Antoni; Geibert, Walter; Gersonde, Rainer; Masqué, Pere; Gaspari, Vania; Barbante, Carlo

    2009-03-01

    Paleoclimatic reconstructions have provided a unique data set to test the sensitivity of climate system to changes in atmospheric CO2 concentrations. However, the mechanisms behind glacial/interglacial (G/IG) variations in atmospheric CO2 concentrations observed in the Antarctic ice cores are still not fully understood. Here we present a new multiproxy data set of sea surface temperatures (SST), dust and iron supply, and marine export productivity, from the marine sediment core PS2489-2/ODP Site 1090 located in the subantarctic Atlantic, that allow us to evaluate various hypotheses on the role of the Southern Ocean (SO) in modulating atmospheric CO2 concentrations back to 1.1 Ma. We show that Antarctic atmospheric temperatures are closely linked to changes in SO surface temperatures over the last 800 ka and use this to synchronize the timescales of our marine and the European Project for Ice Coring in Antarctica (EPICA) Dome C (EDC) records. The close correlation observed between iron inputs and marine export production over the entire interval implies that the process of iron fertilization of marine biota has been a recurrent process operating in the subantarctic region over the G/IG cycles of the last 1.1 Ma. However, our data suggest that marine productivity can only explain a fraction of atmospheric CO2 changes (up to around 40-50 ppmv), occurring at glacial maxima in each glacial stage. In this sense, the good correlation of our SST record to the EDC temperature reconstruction suggests that the initial glacial CO2 decrease, as well as the change in the amplitude of the CO2 cycles observed around 400 ka, was most likely driven by physical processes, possibly related to changes in Antarctic sea ice extent, surface water stratification, and westerly winds position.

  20. Stoichiometry and temperature sensitivity of methanogenesis and CO2 production from saturated polygonal tundra in Barrow, Alaska.

    Science.gov (United States)

    Roy Chowdhury, Taniya; Herndon, Elizabeth M; Phelps, Tommy J; Elias, Dwayne A; Gu, Baohua; Liang, Liyuan; Wullschleger, Stan D; Graham, David E

    2015-02-01

    Arctic permafrost ecosystems store ~50% of global belowground carbon (C) that is vulnerable to increased microbial degradation with warmer active layer temperatures and thawing of the near surface permafrost. We used anoxic laboratory incubations to estimate anaerobic CO2 production and methanogenesis in active layer (organic and mineral soil horizons) and permafrost samples from center, ridge and trough positions of water-saturated low-centered polygon in Barrow Environmental Observatory, Barrow AK, USA. Methane (CH4 ) and CO2 production rates and concentrations were determined at -2, +4, or +8 °C for 60 day incubation period. Temporal dynamics of CO2 production and methanogenesis at -2 °C showed evidence of fundamentally different mechanisms of substrate limitation and inhibited microbial growth at soil water freezing points compared to warmer temperatures. Nonlinear regression better modeled the initial rates and estimates of Q10 values for CO2 that showed higher sensitivity in the organic-rich soils of polygon center and trough than the relatively drier ridge soils. Methanogenesis generally exhibited a lag phase in the mineral soils that was significantly longer at -2 °C in all horizons. Such discontinuity in CH4 production between -2 °C and the elevated temperatures (+4 and +8 °C) indicated the insufficient representation of methanogenesis on the basis of Q10 values estimated from both linear and nonlinear models. Production rates for both CH4 and CO2 were substantially higher in organic horizons (20% to 40% wt. C) at all temperatures relative to mineral horizons (<20% wt. C). Permafrost horizon (~12% wt. C) produced ~5-fold less CO2 than the active layer and negligible CH4 . High concentrations of initial exchangeable Fe(II) and increasing accumulation rates signified the role of iron as terminal electron acceptors for anaerobic C degradation in the mineral horizons. Published 2014. This article is a U.S. Government work and is in the public domain in

  1. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals.

    Science.gov (United States)

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-09-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals.

  2. Effects of Temperature and pCO2 on Population Regulation of Symbiodinium spp. in a Tropical Reef Coral.

    Science.gov (United States)

    Baghdasarian, Garen; Osberg, Andrew; Mihora, Danielle; Putnam, Hollie; Gates, Ruth D; Edmunds, Peter J

    2017-04-01

    This study tested the bleaching response of the Pacific coral Seriatopora caliendrum to short-term exposure to high temperature and elevated partial pressure of carbon dioxide (pCO2). Juvenile colonies collected from Nanwan Bay, Taiwan, were used in a factorial experimental design in which 2 temperatures (∼27.6 °C and ∼30.4 °C) and 2 pCO2 values (∼47.2 Pa and ∼90.7 Pa) were crossed to evaluate, over 12 days, the effects on the densities and physiology of the symbiotic dinoflagellates (Symbiodinium) in the corals. Thermal bleaching, as defined by a reduction of Symbiodinium densities at high temperature, was unaffected by high pCO2. The division, or mitotic index (MI), of Symbiodinium remaining in thermally bleached corals was about 35% lower than in control colonies, but they contained about 53% more chlorophyll. Bleaching was highly variable among colonies, but the differences were unrelated to MI or pigment content of Symbiodinium remaining in the coral host. At the end of the study, all of the corals contained clade C Symbiodinium (either C1d or C15), and the genetic variation of symbionts did not account for among-colony bleaching differences. These results showed that high temperature causes coral bleaching independent of pCO2, and underscores the potential role of the coral host in driving intraspecific variation in coral bleaching.

  3. 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

  4. Temperature dependence of the relationship between pCO2 and dissolved organic carbon in lakes

    KAUST Repository

    Pinho, L.

    2016-02-15

    The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for low-latitude lakes (< 33°), despite very broad ranges in both pCO2 and DOC levels. These results suggest substantial differences in the carbon cycling of low-latitude lakes, which must be considered when upscaling limnetic carbon cycling to global scales.

  5. CO2 CAPTURE PROJECT-AN INTEGRATED, COLLABORATIVE TECHNOLOGY DEVELOPMENT PROJECT FOR NEXT GENERATION CO2 SEPARATION, CAPTURE AND GEOLOGIC SEQUESTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Helen Kerr

    2004-04-01

    The CO{sub 2} Capture Project (CCP) is a joint industry project, funded by eight energy companies (BP, ChevronTexaco, EnCana, Eni, Norsk Hydro, Shell, Statoil, and Suncor) and three government agencies (European Union (DG Res & DG Tren), Norway (Klimatek) and the U.S.A. (Department of Energy)). The project objective is to develop new technologies, which could reduce the cost of CO{sub 2} capture and geologic storage by 50% for retrofit to existing plants and 75% for new-build plants. Technologies are to be developed to ''proof of concept'' stage by the end of 2003. The project budget is approximately $24 million over 3 years and the work program is divided into eight major activity areas: (1) Baseline Design and Cost Estimation--defined the uncontrolled emissions from each facility and estimate the cost of abatement in $/tonne CO{sub 2}. (2) Capture Technology, Post Combustion--technologies, which can remove CO{sub 2} from exhaust gases after combustion. (3) Capture Technology, Oxyfuel--where oxygen is separated from the air and then burned with hydrocarbons to produce an exhaust with wet high concentrations of CO{sub 2} for storage. (4) Capture Technology, Pre-Combustion--in which, natural gas and petroleum coke are converted to hydrogen and CO{sub 2} in a reformer/gasifier. (5) Common Economic Model/Technology Screening--analysis and evaluation of each technology applied to the scenarios to provide meaningful and consistent comparison. (6) New Technology Cost Estimation: on a consistent basis with the baseline above, to demonstrate cost reductions. (7) Geologic Storage, Monitoring and Verification (SMV)--providing assurance that CO{sub 2} can be safely stored in geologic formations over the long term. (8) Non-Technical: project management, communication of results and a review of current policies and incentives governing CO{sub 2} capture and storage. Technology development work dominated the past six months of the project. Numerous studies

  6. CO2 Capture Project-An Integrated, Collaborative Technology Development Project for Next Generation CO2 Separation, Capture and Geologic Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Helen Kerr; Linda M. Curran

    2005-04-15

    The CO{sub 2} Capture Project (CCP) was a joint industry project, funded by eight energy companies (BP, ChevronTexaco, EnCana, ENI, Norsk Hydro, Shell, Statoil, and Suncor) and three government agencies (European Union [DG RES & DG TREN], the Norwegian Research Council [Klimatek Program] and the U.S. Department of Energy [NETL]). The project objective was to develop new technologies that could reduce the cost of CO{sub 2} capture and geologic storage by 50% for retrofit to existing plants and 75% for new-build plants. Technologies were to be developed to ''proof of concept'' stage by the end of 2003. Certain promising technology areas were increased in scope and the studies extended through 2004. The project budget was approximately $26.4 million over 4 years and the work program is divided into eight major activity areas: Baseline Design and Cost Estimation--defined the uncontrolled emissions from each facility and estimate the cost of abatement in $/tonne CO{sub 2}. Capture Technology, Post Combustion: technologies, which can remove CO{sub 2} from exhaust gases after combustion. Capture Technology, Oxyfuel: where oxygen is separated from the air and then burned with hydrocarbons to produce an exhaust with high CO{sub 2} for storage. Capture Technology, Pre-Combustion: in which, natural gas and petroleum cokes are converted to hydrogen and CO{sub 2} in a reformer/gasifier. Common Economic Model/Technology Screening: analysis and evaluation of each technology applied to the scenarios to provide meaningful and consistent comparison. New Technology Cost Estimation: on a consistent basis with the baseline above, to demonstrate cost reductions. Geologic Storage, Monitoring and Verification (SMV): providing assurance that CO{sub 2} can be safely stored in geologic formations over the long term. Non-Technical: project management, communication of results and a review of current policies and incentives governing CO{sub 2} capture and storage. Pre

  7. Effect of measurement time of the day on the relationship between temperature and soil CO2 efflux

    Directory of Open Access Journals (Sweden)

    Eva Dařenová

    2011-01-01

    Full Text Available In this study we investigated effect of the time of the day when manual measurements of soil CO2 efflux are performed on estimates of seasonal sums of released carbon from the soil. We subsampled continuous measurement of soil CO2 efflux into six sets of data in accordance to the time of the day when the measurements were taken – 0 h, 4 h, 8 h, 12 h, 16 h and 20 h. To estimate seasonal carbon flux from the soil we used continuously measured soil temperature and parameters R10 (soil CO2 efflux normalized for temperature of 10 °C and Q10 (the proportional change in CO2 efflux caused by 10 °C increase in temperature calculated from continuous measurements and from measurements taken at individual hours. Values of Q10 calculated from 12 h and 16 h data were lower than Q10 calculated from continuous measurements. On the contrary, Q10 at 0 h, 4 h, 8 h and 20 h were higher. Seasonal carbon flux from the soil based on 0 h, 4 h and 8 h measurements was overestimated compare to the flux calculated from continuous measurements. On the contrary, measurements at 12 h, 16 h and 20 h measurements underestimated the carbon flux. The under- or overestimation was significant for 0 h, 4 h, 8 h and 20 h data sub-sets.

  8. 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

  9. 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.

  10. Healing and sliding stability of simulated anhydrite fault gouge : Effects of water, temperature and CO2

    NARCIS (Netherlands)

    Pluymakers, Anne M H; Niemeijer, André R.

    2015-01-01

    Anhydrite-bearing faults are currently of interest to 1) CO2-storage sites capped by anhydrite caprocks (such as those found in the North Sea) and 2) seismically active faults in evaporite formations (such as the Italian Apennines). In order to assess the likelihood of fault reactivation, the mode

  11. Effects of temperature and CO2 on the frictional behavior of simulated anhydrite fault rock

    NARCIS (Netherlands)

    Pluymakers, Anne M.H.; Samuelson, Jon E.; Niemeijer, André; Spiers, Christopher

    2014-01-01

    The frictional behavior of anhydrite‐bearing faults is of interest to a) the safety and effectiveness of CO2 storage in anhydrite‐capped reservoirs, b) seismicity induced by hydrocarbon production, and c) natural seismicity nucleated in evaporite formations. We performed direct shear experiments on

  12. Two-phase change in CO2, Antarctic temperature and global climate during Termination II

    NARCIS (Netherlands)

    Landais, A.; Dreyfus, G.; Capron, E.; Jouzel, J; Masson-Delmotte, V.; Roche, D.M.V.A.P.; Prie, F; Caillon, N.

    2013-01-01

    The end of the Last Glacial Maximum (Termination I), roughly 20 thousand years ago (ka), was marked by cooling in the Northern Hemisphere, a weakening of the Asian monsoon, a rise in atmospheric CO 2 concentrations and warming over Antarctica. The sequence of events associated with the previous

  13. Impact of temperature, CO2 fixation and nitrate reduction on selenium reduction, by a paddy soil Clostridium strain.

    Science.gov (United States)

    Bao, P; Huang, H; Hu, Z-Y; Häggblom, M M; Zhu, Y-G

    2013-03-01

    To elucidate the impact of CO(2) fixation, nitrate reduction and temperature on selenium reduction by a newly identified acetogenic bacterium, Clostridium sp. BXM. A series of culture experiments were designed to evaluate the impact of temperature, CO(2) fixation and nitrate reduction on the rate and extent of selenium reduction by strain BXM. The products of selenium reduction, CO(2) fixation and nitrate reduction were determined. Molecular analysis was performed to identify the functional genes involved in the selenium reduction process. CO(2) may have enhanced the activity of hydrogenase I and/or the level of cytochrome b, thus increasing selenium reduction. Nitrate may inhibit selenium reduction due to its higher reduction potential and/or by decreasing selenite/selenate reductase activity. The suitable temperature was 37 and 30 °C for selenite reduction under anaerobic and aerobic conditions, respectively. The optimum temperature was 30 °C for selenate reduction under both anaerobic and aerobic conditions. CO(2) fixation and nitrate reduction by Clostridium sp. BXM stimulated each other. Clostridium sp. BXM was capable of reducing up to 36-94% of 1 mmol l(-1) selenate and selenite under anaerobic or aerobic conditions over 15 days. The strain might be used for the precipitation of Se from highly selenium-contaminated water or sediments. The findings contribute to the current understanding about the role that micro-organisms play in the detoxification of toxic selenium compounds in paddy soils. Micro-organisms in paddy soils can influence selenium accumulation in rice grain and hence human selenium intake. © 2012 The Society for Applied Microbiology.

  14. The effect of increased atmospheric temperature and CO2 concentration during crop growth on the chemical composition and in vitro rumen fermentation characteristics of wheat straw.

    Science.gov (United States)

    He, Xiangyu; Wu, Yanping; Cai, Min; Mu, Chunlong; Luo, Weihong; Cheng, Yanfen; Zhu, Weiyun

    2015-01-01

    This experiment was conducted to investigate the effects of increased atmospheric temperature and CO2 concentration during crop growth on the chemical composition and in vitro rumen fermentation characteristics of wheat straw. The field experiment was carried out from November 2012 to June 2013 at Changshu (31°32'93″N, 120°41'88″E) agro-ecological experimental station. A total of three treatments were set. The concentration of CO2 was increased to 500 μmol/mol in the first treatment (CO2 group). The temperature was increased by 2 °C in the second treatment (TEM group) and the concentration of CO2 and temperature were both increased in the third treatment (CO2 + TEM group). The mean temperature and concentration of CO2 in control group were 10.5 °C and 413 μmol/mol. At harvesting, the wheat straws were collected and analyzed for chemical composition and in vitro digestibility. Results showed that dry matter was significantly increased in all three treatments. Ether extracts and neutral detergent fiber were significantly increased in TEM and CO2 + TEM groups. Crude protein was significantly decreased in CO2 + TEM group. In vitro digestibility analysis of wheat straw revealed that gas production was significantly decreased in CO2 and CO2 + TEM groups. Methane production was significantly decreased in TEM and CO2 + TEM groups. Ammonia nitrogen and microbial crude protein were significantly decreased in all three treatments. Total volatile fatty acids were significantly decreased in CO2 and CO2 + TEM groups. In conclusion, the chemical composition of the wheat straw was affected by temperature and CO2 and the in vitro digestibility of wheat straw was reduced, especially in the combined treatment of temperature and CO2.

  15. Adsorption and separation of CO2 on KFI zeolites: effect of cation type and Si/Al ratio on equilibrium and kinetic properties.

    Science.gov (United States)

    Remy, Tom; Peter, Sunil A; Van Tendeloo, Leen; Van der Perre, Stijn; Lorgouilloux, Yannick; Kirschhock, Christine E A; Martens, Johan A; Xiong, Yanliang; Baron, Gino V; Denayer, Joeri F M

    2013-04-23

    Selective separation of CO2 is becoming one of the key technologies in the (petro-) chemical industry. This study focuses on the adsorption and separation of CO2 from CH4 on a new low-silica (LS) type of the eight-membered ring KFI zeolite. A series of alkali (Li, Na, K) and alkaline-earth (Mg, Ca, Sr) exchanged samples of the new LS KFI were synthesized and characterized. LS Li-KFI showed the largest pore volume, whereas LS Na-KFI and LS K-KFI were inaccessible for Argon at 87 K. Adsorption of CO2 at 303 K demonstrated the dominant quadrupolar interaction on alkali-exchanged LS KFI samples. LS Li-KFI showed the largest capacities upon high pressure isotherm measurements of CO2 (4.8 mmol/g), CH4 (2.6 mmol/g), and N2 (2.2 mmol/g) up to 40 bar at 303 K. The performance of the new LS KFI was compared to a KFI sample (ZK-5) with a higher Si/Al ratio. Isotherm measurements and dynamic breakthrough experiments demonstrated that ZK-5 samples show larger working capacities for CO2/CH4 separations at low pressure. Li-ZK-5 and Na-ZK-5 show the highest capacities and high selectivities (similar to benchmark 13X).

  16. 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.

  17. Effects of temperature, CO2/O2 concentrations and light intensity on cellular multiplication of microalgae, Euglena gracilis

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    2005-01-01

    Microalgae culture is likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO2 to O2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular multiplication of microalgae, Euglena gracilis, was investigated as a fundamental study to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperatures (25-33 degrees C), three levels of CO2 concentrations (2-6%), five levels of O2 concentrations (10-30%), and six levels of photosynthetic photon flux (20-200 micromoles m-2 s-1). The number of Euglena cells in a certain volume of solution was monitored with a microscope under each environmental condition. The multiplication rate of the cells was highest at temperatures of 27-31 degrees C, CO2 concentration of 4%, O2 concentration of 20% and photosynthetic photon flux of about 100 micromoles m-2 s-1. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO2 to O2 under relatively low light intensities in aquatic food production modules. c2005 Published by Elsevier Ltd on behalf of COSPAR.

  18. Effects of temperature, CO 2/O 2 concentrations and light intensity on cellular multiplication of microalgae, Euglena gracilis

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    Microalgae culture is likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO 2 to O 2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular multiplication of microalgae, Euglena gracilis, was investigated as a fundamental study to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperatures (25-33 °C), three levels of CO 2 concentrations (2-6%), five levels of O 2 concentrations (10-30%), and six levels of photosynthetic photon flux (20-200 μmol m -2 s -1). The number of Euglena cells in a certain volume of solution was monitored with a microscope under each environmental condition. The multiplication rate of the cells was highest at temperatures of 27-31 °C, CO 2 concentration of 4%, O 2 concentration of 20% and photosynthetic photon flux of about 100 μmol m -2 s -1. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO 2 to O 2 under relatively low light intensities in aquatic food production modules.

  19. Drought responses of two gymnosperm species with contrasting stomatal regulation strategies under elevated [CO2] and temperature.

    Science.gov (United States)

    Duan, Honglang; O'Grady, Anthony P; Duursma, Remko A; Choat, Brendan; Huang, Guomin; Smith, Renee A; Jiang, Yanan; Tissue, David T

    2015-07-01

    Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (C(a) (ambient, 400 μl l(-1)) and C(e) (elevated, 640 μl l(-1))) and two temperature (T(a) (ambient) and T(e) (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. C(e) did not delay the time-to-mortality in either species under drought or T(e) treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l(-1)) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought.

  20. 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.

  1. Accumulation of secondary metabolites in healthy and diseased barley, grown under future climate levels of CO2, ozone and temperature.

    Science.gov (United States)

    Mikkelsen, B L; Olsen, C E; Lyngkjær, M F

    2015-10-01

    Plants produce secondary metabolites promoting adaptation to changes in the environment and challenges by pathogenic microorganisms. A future climate with increased temperature and CO2 and ozone levels will likely alter the chemical composition of plants and thereby plant-pathogen interactions. To investigate this, barley was grown at elevated CO2, temperature and ozone levels as single factors or in combination resembling future climatic conditions. Increased basal resistance to the powdery mildew fungus was observed when barley was grown under elevated CO2, temperature and ozone as single factors. However, this effect was neutralized in the combination treatments. Twenty-five secondary metabolites were putatively identified in healthy and diseased barley leaves, including phenylpropanoids, phenolamides and hydroxynitrile glucosides. Accumulation of the compounds was affected by the climatic growth conditions. Especially elevated temperature, but also ozone, showed a strong impact on accumulation of many compounds, suggesting that these metabolites play a role in adaptation to unfavorable growth conditions. Many compounds were found to increase in powdery mildew diseased leaves, in correlation with a strong and specific influence of the climatic growth conditions. The observed disease phenotypes could not be explained by accumulation of single compounds. However, decreased accumulation of the powdery mildew associated defense compound p-coumaroylhydroxyagmatine could be implicated in the increased disease susceptibility observed when barley was grown under combination of elevated CO2, temperature and ozone. The accumulation pattern of the compounds in both healthy and diseased leaves from barley grown in the combination treatments could not be deduced from the individual single factor treatments. This highlights the complex role and regulation of secondary metabolites in plants' adaptation to unfavorable growth conditions. Copyright © 2015 Elsevier Ltd. All

  2. 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.

  3. Role of intrachain rigidity in the plasticization of intrinsically microporous triptycene-based polyimide membranes in mixed-Gas CO2/CH4 separations

    KAUST Repository

    Swaidan, Raja

    2014-11-11

    Based on high-pressure pure- and mixed-gas (50:50) CO2/CH4 separation properties of two intrinsically microporous triptycene-based polyimides (TPDA-TMPD and TPDA-6FpDA), the intrachain rigidity central to "conventional PIM" design principles is not a singular solution to intrinsic plasticization resistance. Despite the significant intrachain rigidity in TPDA-TMPD, a 300% increase in PMIX(CH4), 50% decrease in α(CO2/CH4) from 24 to 12, and continuous increase in PMIX(CO2) occurred from 4 to 30 bar. On the other hand, the more flexible and densely packed TPDA-6FpDA exhibited a slight upturn in PMIX(CO2) at 20 bar similar to a dense cellulose acetate (CA) film, also reported here, despite a 4-fold higher CO2 sorption capacity. Microstructural investigations suggest that the interconnected O2- and H2-sieving ultramicroporosity of TPDA-TMPD is more sensitive to slight CO2-induced dilations and is the physical basis for a more extensive and accelerated plasticization. Interchain rigidity, potentially by interchain interactions, is emphasized and may be facilitated by intrachain mobility.

  4. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G. [East Tennessee Technology Park, Oak Ridge, TN (United States)

    1997-12-01

    The separative performance of the authors` ceramic membranes has been determined in the past using a permeance test system that measured flows of pure gases through a membrane at temperatures up to 275 C. From these data, the separation factor was determined for a particular gas pair from the ratio of the pure gas specific flows. An important project goal this year has been to build a Mixed Gas Separation System (MGSS) for measuring the separation efficiencies of membranes at higher temperatures and using mixed gases. The MGSS test system has been built, and initial operation has been achieved. The MGSS is capable of measuring the separation efficiency of membranes at temperatures up to 600 C and pressures up to 100 psi using a binary gas mixture such as hydrogen/methane. The mixed gas is fed into a tubular membrane at pressures up to 100 psi, and the membrane separates the feed gas mixture into a permeate stream and a raffinate stream. The test membrane is sealed in a stainless steel holder that is mounted in a split tube furnace to permit membrane separations to be evaluated at temperatures up to 600 C. The compositions of the three gas streams are measured by a gas chromatograph equipped with thermal conductivity detectors. The test system also measures the temperatures and pressures of all three gas streams as well as the flow rate of the feed stream. These data taken over a range of flows and pressures permit the separation efficiency to be determined as a function of the operating conditions. A mathematical model of the separation has been developed that permits the data to be reduced and the separation factor for the membrane to be determined.

  5. 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.

  6. 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.

  7. Pure- and mixed-gas CO2/CH4 separation properties of PIM-1 and an amidoxime-functionalized PIM-1

    KAUST Repository

    Swaidan, Raja

    2014-05-01

    The prototypical solution-processable polymer of intrinsic microporosity, PIM-1, and derivatives thereof offer combinations of permeability and selectivity that make them potential candidate materials for membrane-based gas separations. Paramount to the design and evaluation of PIMs for economical natural gas sweetening is a high and stable CO2/CH4 selectivity under realistic, mixed-gas conditions. Here, amidoxime-functionalized PIM-1 (AO-PIM-1) was prepared and examined for fundamental structure/property relationships. Qualitative NLDFT pore-size distribution analyses of physisorption isotherms (N2 at -196 oC; CO2 at 0 oC) reveal a tightened microstructure indicating size-sieving ultra-microporosity (<7Å). AO-PIM-1 demonstrated a three-fold increase in αD(CO2/CH4) over PIM-1, surpassing the 2008 upper bound with P(CO2)=1153Barrer and ideal α(CO2/CH4)=34. Under a 50:50 CO2:CH4 mixed-gas feed, AO-PIM-1 showed less selectivity loss than PIM-1, maintaining a mixed-gas α(CO2/CH4) ~21 across a 20bar pressure range. Conversely, PIM-1 endured up to 60% increases in mixed-gas CH4 permeability over pure-gas values concurrent with a selectivity of only ~8 at 20bar. A pervasive intermolecular hydrogen bonding network in AO-PIM-1 predominantly yields a rigidified microstructure that mitigates CO2-induced matrix dilations, reducing detrimental mixed-gas CH4 copermeation. © 2014 Elsevier B.V.

  8. 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.

  9. Sensory Qualities of Oysters Unaltered by a Short Exposure to Combined Elevated pCO2 and Temperature

    Directory of Open Access Journals (Sweden)

    Anaëlle J. Lemasson

    2017-11-01

    Full Text Available Reliance on the marine environment for the provision of food is ever-increasing, but future climate change threatens production. Despite this concern, the impact on seafood quality and success of the seafood industry is unknown. Using a short-term study, we test these concerns using a major aquaculture species—Crassostrea gigas—exposing them to three acidification and warming scenarios: (1 ambient pCO2 (~400 ppm & control temperature (15°C, (2 ambient pCO2 (~400 ppm & elevated temperature (20°C, (3 elevated pCO2 (~1,000 ppm & elevated temperature (20°C. Oyster quality was assessed by scoring appearance, aroma, taste, and overall acceptability. A panel of five experts was asked to score nine oysters—three from each treatment—according to agreed criteria. Results indicate that these levels of acidification and warming did not significantly alter the sensory properties of C. gigas, and notably the overall acceptability remained unchanged. Non-statistically supported trends suggest that several sensory attributes—opacity, mouthfeel, aspect of meat, shininess, meat resistance, meat texture, and creaminess—may improve under acidification and warming scenarios. These findings can be considered positive for the future of the aquaculture and food sectors. Crassostrea gigas therefore is expected to remain a key species for food security that is resilient to climate change, whilst retaining its valuable attributes.

  10. Temperature and atmospheric CO2 concentration estimates through the PETM using triple oxygen isotope analysis of mammalian bioapatite.

    Science.gov (United States)

    Gehler, Alexander; Gingerich, Philip D; Pack, Andreas

    2016-07-12

    The Paleocene-Eocene Thermal Maximum (PETM) is a remarkable climatic and environmental event that occurred 56 Ma ago and has importance for understanding possible future climate change. The Paleocene-Eocene transition is marked by a rapid temperature rise contemporaneous with a large negative carbon isotope excursion (CIE). Both the temperature and the isotopic excursion are well-documented by terrestrial and marine proxies. The CIE was the result of a massive release of carbon into the atmosphere. However, the carbon source and quantities of CO2 and CH4 greenhouse gases that contributed to global warming are poorly constrained and highly debated. Here we combine an established oxygen isotope paleothermometer with a newly developed triple oxygen isotope paleo-CO2 barometer. We attempt to quantify the source of greenhouse gases released during the Paleocene-Eocene transition by analyzing bioapatite of terrestrial mammals. Our results are consistent with previous estimates of PETM temperature change and suggest that not only CO2 but also massive release of seabed methane was the driver for CIE and PETM.

  11. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1996-08-01

    Ceramic gas separation membranes can provide very high separation factors if the pore size is sufficiently small to separate gas molecules by molecular sieving and if oversized pores are adequately limited. Ceramic membranes typically have some pores that are substantially larger than the mean pore size and that should be regarded as defects. To assess the effects of such defects on the performance of ceramic membranes, a simple mathematical model has been developed to describe flow through a gas separation membrane that has a primary mode of flow through very small pores but that has a secondary mode of flow through undesirably large pores. This model permits separation factors to be calculated for a specified gas pair as a function of the molecular weights and molecular diameters of the gases, the membrane pore diameter, and the diameter and number of defects. This model will be described, and key results from the model will be presented. The separation factors of the authors membranes continue to be determined using a permeance test system that measures flows of pure gases through a membrane at temperatures up to 275{degrees}C. A primary goal of this project for FY 1996 is to develop a mixed gas separation system for measuring the separation efficiency of membranes at higher temperatures. Performance criteria have been established for the planned mixed gas separation system and design of the system has been completed. The test system is designed to measure the separation efficiency of membranes at temperatures up to 600{degrees}C and pressures up to 100 psi by separating the constituents of a gas mixture containing hydrogen. The system will accommodate the authors typical experimental membrane that is tubular and has a diameter of about 9 mm and a length of about 23 cm. The design of the new test system and its expected performance will be discussed.

  12. CO2 and water vapour exchange in four alpine herbs at two altitudes and under varying light and temperature conditions.

    Science.gov (United States)

    Rawat, A S; Purohit, A N

    1991-06-01

    CO2 and water vapour exchange rates of four alpine herbs namely: Rheum emodi, R. moorcroftianum, Megacarpaea polyandra and Rumex nepalensis were studied under field conditions at 3600 m (natural habitat) and 550 m altitudes. The effect of light and temperature on CO2 and water vapour exchange was studied in the plants grown at lower altitude. In R. moorcroftianum and R. nepalensis, the average photosynthesis rates were found to be about three times higher at 550 m as compared to that under their natural habitat. However, in M. polyandra, the CO2 exchange rates were two times higher at 3600 m than at 550 m but in R. emodi, there were virtually no differences at the two altitudes. These results indicate the variations in the CO2 exchange rates are species specific. The change in growth altitude does not affect this process uniformly.The transpiration rates in R. emodi and M. polyandra were found to be very high at 3600 m compared to 550 m and are attributed to overall higher stomatal conductance in plants of these species, grown at higher altitude. The mid-day closure of stomata and therefore, restriction of transpirational losses of water were observed in all the species at 550 m altitude. In addition to the effect of temperature and relative humidity, the data also indicate some endogenous rhythmic control of stomatal conductance.The temperature optima for photosynthesis was close to 30°C in M. polyandra and around 20°C in the rest of the three species. High temperature and high light intensity, as well as low temperature and high light intensity, adversely affect the net rate of photosynthesis in these species.Both light compensation point and dark respiration rate increased with increasing temperature.The effect of light was more prominent on photosynthesis than the effect of temperature, however, on transpiration the effect of temperature was more prominent than the effect of light intensity.No definite trends were found in stomatal conductance with respect to

  13. LASER EMISSIONS FROM CO2 VIBRATIONAL TRANSITIONS IN A LOW TEMPERATURE SUPERSONIC FLOW EXCITED BY A PULSED ELECTRON BEAM STABILIZED DISCHARGE

    OpenAIRE

    Fontaine, B.; Forestier, B.; Gross, P.; Koudriavtsev, E.

    1980-01-01

    High power long pulse infrared laser emission has been achieved on CO2 molecule with the high density and very low temperature supersonic flow-electron beam-stabilized discharge excitation device developped at I.M.F.M. ([MATH] [MATH] 2 amagats, T [MATH] 70 - 150 K). Laser emission at [MATH] = 10.6 µ has been achieved for a resonant cavity set at the discharge location and also 3 cm downstream of the discharge location. With Ar/CO2, Ar/CO2/H2, He/CO2, and He/CO2/N2 mixtures, lasing energy and ...

  14. Modeling of mass transfer of Phospholipids in separation process with supercritical CO2 fluid by RBF artificial neural networks

    Science.gov (United States)

    An artificial Radial Basis Function (RBF) neural network model was developed for the prediction of mass transfer of the phospholipids from canola meal in supercritical CO2 fluid. The RBF kind of artificial neural networks (ANN) with orthogonal least squares (OLS) learning algorithm were used for mod...

  15. The effect of nonlinearity in CO2 heating rates on the attribution of stratospheric ozone and temperature changes

    Directory of Open Access Journals (Sweden)

    T. G. Shepherd

    2009-11-01

    Full Text Available An analysis of the attribution of past and future changes in stratospheric ozone and temperature to anthropogenic forcings is presented. The analysis is an extension of the study of Shepherd and Jonsson (2008 who analyzed chemistry-climate simulations from the Canadian Middle Atmosphere Model (CMAM and attributed both past and future changes to changes in the external forcings, i.e. the abundances of ozone-depleting substances (ODS and well-mixed greenhouse gases. The current study is based on a new CMAM dataset and includes two important changes. First, we account for the nonlinear radiative response to changes in CO2. It is shown that over centennial time scales the radiative response in the upper stratosphere to CO2 changes is significantly nonlinear and that failure to account for this effect leads to a significant error in the attribution. To our knowledge this nonlinearity has not been considered before in attribution analysis, including multiple linear regression studies. For the regression analysis presented here the nonlinearity was taken into account by using CO2 heating rate, rather than CO2 abundance, as the explanatory variable. This approach yields considerable corrections to the results of the previous study and can be recommended to other researchers. Second, an error in the way the CO2 forcing changes are implemented in the CMAM was corrected, which significantly affects the results for the recent past. As the radiation scheme, based on Fomichev et al. (1998, is used in several other models we provide some description of the problem and how it was fixed.

  16. Fabrication of 6FDA-durene membrane incorporated with zeolite T and aminosilane grafted zeolite T for CO2/CH4 separation

    Science.gov (United States)

    Jusoh, Norwahyu; Fong Yeong, Yin; Keong Lau, Kok; Shariff, Azmi Mohd

    2017-08-01

    In the present work, zeolite T and aminosilane grafted zeolite T are embedded into 6FDA-durene polyimide phase for the fabrication of mixed matrix membranes (MMMs). FESEM images demonstrated that the improvement of interfacial adhesion between zeolite and polymer phases in MMM loaded with aminosilane grafted zeolite T was not significant as compared to zeolite T/6FDA-durene MMM. From the gas permeation test, CO2/CH4 selectivity up to 26.4 was achieved using MMM containing aminosilane grafted zeolite T, while MMM loaded with ungrafted zeolite T showed CO2/CH4 selectivity of 19.1. In addition, MMM incorporated with aminosilane grafted zeolite T particles successfully lies on Robeson upper bound 2008, which makes it an attractive candidate for CO2/CH4 separation.

  17. Final Report for Fractionation and Separation of Polydisperse Nanoparticles into Distinct Monodisperse Fractions Using CO2 Expanded Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Chistopher Roberts

    2007-08-31

    The overall objective of this project was to facilitate efficient fractionation and separation of polydisperse metal nanoparticle populations into distinct monodisperse fractions using the tunable solvent properties of gas expanded liquids. Specifically, the dispersibility of ligand-stabilized nanoparticles in an organic solution was controlled by altering the ligand-solvent interaction (solvation) by the addition of carbon dioxide (CO{sub 2}) gas as an antisolvent (thereby tailoring the bulk solvent strength) in a custom high pressure apparatus developed in our lab. This was accomplished by adjusting the CO{sub 2} pressure over the liquid dispersion, resulting in a simple means of tuning the nanoparticle precipitation by size. Overall, this work utilized the highly tunable solvent properties of organic/CO{sub 2} solvent mixtures to selectively size-separate dispersions of polydisperse nanoparticles (ranging from 1 to 20 nm in size) into monodisperse fractions ({+-}1nm). Specifically, three primary tasks were performed to meet the overall objective. Task 1 involved the investigation of the effects of various operating parameters (such as temperature, pressure, ligand length and ligand type) on the efficiency of separation and fractionation of Ag nanoparticles. In addition, a thermodynamic interaction energy model was developed to predict the dispersibility of different sized nanoparticles in the gas expanded liquids at various conditions. Task 2 involved the extension of the experimental procedures identified in task 1 to the separation of other metal particles used in catalysis such as Au as well as other materials such as semiconductor particles (e.g. CdSe). Task 3 involved using the optimal conditions identified in tasks 1 and 2 to scale up the process to handle sample sizes of greater than 1 g. An experimental system was designed to allow nanoparticles of increasingly smaller sizes to be precipitated sequentially in a vertical series of high pressure vessels by

  18. Effects of simultaneously elevated temperature and CO2 levels on Nicotiana benthamiana and its infection by different positive-sense RNA viruses are cumulative and virus type-specific.

    Science.gov (United States)

    Del Toro, Francisco J; Rakhshandehroo, Farshad; Larruy, Beatriz; Aguilar, Emmanuel; Tenllado, Francisco; Canto, Tomás

    2017-11-01

    We have studied how simultaneously elevated temperature and CO2 levels [climate change-related conditions (CCC) of 30°C, 970 parts-per-million (ppm) of CO2 vs. standard conditions (SC) of 25°C, ~ 405ppm CO2] affect physiochemical properties of Nicotiana benthamiana leaves, and also its infection by several positive-sense RNA viruses. In previous works we had studied effects of elevated temperature, CO2 levels separately. Under CCC, leaves of healthy plants almost doubled their area relative to SC but contained less protein/unit-of-area, similarly to what we had found under conditions of elevated CO2 alone. CCC also affected the sizes/numbers of different foliar cell types differently. Under CCC, infection outcomes in titers and symptoms were virus type-specific, broadly similar to those observed under elevated temperature alone. Under either condition, infections did not significantly alter the protein content of leaf discs. Therefore, effects of elevated temperature and CO2 combined on properties of the pathosystems studied were overall cumulative. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. The Feasibility of Detecting a Burner-Can Burn-Through by Means of CO, CO2, Pressure, and Air Temperature Levels in a Jet Engine Nacelle.

    Science.gov (United States)

    feasibility of detecting a burn-through by monitoring the carbon monoxide (CO), carbon dioxide (CO2), a pressure level, or air temperature in the nacelle...before, during, and after engine case rupture. Results of the tests indicated that CO, CO2, pressure, and air temperature in the nacelle cannot be

  20. Biomass Production Potential of a Wastewater Alga Chlorella vulgaris ARC 1 under Elevated Levels of CO2 and Temperature

    National Research Council Canada - National Science Library

    Chinnasamy, Senthil; Ramakrishnan, Balasubramanian; Bhatnagar, Ashish; Das, Keshav C

    2009-01-01

    .... vulgaris at ambient CO2 (0.036%), were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them...

  1. A room temperature CO$_2$ line list with ab initio computed intensities

    CERN Document Server

    Zak, Emil; Polyansky, Oleg L; Lodi, Lorenzo; Zobov, Nikolay F; Tashkun, Sergey A; Perevalov, Valery I

    2016-01-01

    Atmospheric carbon dioxide concentrations are being closely monitored by remote sensing experiments which rely on knowing line intensities with an uncertainty of 0.5% or better. We report a theoretical study providing rotation-vibration line intensities substantially within the required accuracy based on the use of a highly accurate {\\it ab initio} dipole moment surface (DMS). The theoretical model developed is used to compute CO$_2$ intensities with uncertainty estimates informed by cross comparing line lists calculated using pairs of potential energy surfaces (PES) and DMS's of similar high quality. This yields lines sensitivities which are utilized in reliability analysis of our results. The final outcome is compared to recent accurate measurements as well as the HITRAN2012 database. Transition frequencies are obtained from effective Hamiltonian calculations to produce a comprehensive line list covering all $^{12}$C$^{16}$O$_2$ transitions below 8000 cm$^{-1}$ and stronger than 10$^{-30}$ cm / molecule at ...

  2. 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.

  3. Equations for O2 and CO2 solubilities in saline and plasma: combining temperature and density dependences.

    Science.gov (United States)

    Christmas, Kevin M; Bassingthwaighte, James B

    2017-05-01

    Solubilities of respiratory gasses in water, saline, and plasma decrease with rising temperatures and solute concentrations. Henry's Law, C = α·P, states that the equilibrium concentration of a dissolved gas is solubility times partial pressure. Solubilities in the water of a solution depend on temperature and the content of other solutes. Blood temperatures may differ more than 20°C between skin and heart, and an erythrocyte will undergo that range as blood circulates. The concentrations of O2 and CO2 are the driving forces for diffusion, exchanges, and for reactions. We provide an equation for O2 and CO2 solubilities, α, that allows for continuous changes in temperature, T, and solution density, ρ, in dynamically changing states:[Formula: see text]This two-exponential expression with a density scalar γ, and a density exponent β, accounts for solubility changes due to density changes of an aqueous solution. It fits experimental data on solubilities in water, saline, and plasma over temperatures from 20 to 40°C, and for plasma densities, ρsol up to 1.020 g/ml with ~0.3% error. The amounts of additional bound O2 (to Hb) and CO2 (bicarbonate and carbamino) depend on the concentrations in the local water space and the reaction parameters. During exercise, solubility changes are large; both ρsol and T change rapidly with spatial position and with time. In exercise hemoconcentration plasma, ρsol exceeds 1.02, whereas T may range over 20°C. The six parameters for O2 and the six for CO2 are constants, so solubilities are calculable continuously as T and ρsol change.NEW & NOTEWORTHY Solubilities for oxygen and carbon dioxide are dependent on the density of the solution, on temperature, and on the partial pressure. We provide a brief equation suitable for hand calculators or mathematical modeling, accounting for these factors over a wide range of temperatures and solution densities for use in rapidly changing conditions, such as extreme exercise or osmotic

  4. Effects of experimental water table and temperature manipulations on ecosystem CO2 fluxes in an Alaskan rich fen

    Science.gov (United States)

    Chivers, M.R.; Turetsky, M.R.; Waddington, J.M.; Harden, J.W.; McGuire, A.D.

    2009-01-01

    Peatlands store 30% of the world's terrestrial soil carbon (C) and those located at northern latitudes are expected to experience rapid climate warming. We monitored growing season carbon dioxide (CO2) fluxes across a factorial design of in situ water table (control, drought, and flooded plots) and soil warming (control vs. warming via open top chambers) treatments for 2 years in a rich fen located just outside the Bonanza Creek Experimental Forest in interior Alaska. The drought (lowered water table position) treatment was a weak sink or small source of atmospheric CO2 compared to the moderate atmospheric CO2 sink at our control. This change in net ecosystem exchange was due to lower gross primary production and light-saturated photosynthesis rather than increased ecosystem respiration. The flooded (raised water table position) treatment was a greater CO2 sink in 2006 due largely to increased early season gross primary production and higher light-saturated photosynthesis. Although flooding did not have substantial effects on rates of ecosystem respiration, this water table treatment had lower maximum respiration rates and a higher temperature sensitivity of ecosystem respiration than the control plot. Surface soil warming increased both ecosystem respiration and gross primary production by approximately 16% compared to control (ambient temperature) plots, with no net effect on net ecosystem exchange. Results from this rich fen manipulation suggest that fast responses to drought will include reduced ecosystem C storage driven by plant stress, whereas inundation will increase ecosystem C storage by stimulating plant growth. ?? 2009 Springer Science+Business Media, LLC.

  5. Diverging temperature responses of CO2 assimilation and plant development explain the overall effect of temperature on biomass accumulation in wheat leaves and grains.

    Science.gov (United States)

    Collins, Nicholas C; Parent, Boris

    2017-01-09

    There is a growing consensus in the literature that rising temperatures influence the rate of biomass accumulation by shortening the development of plant organs and the whole plant and by altering rates of respiration and photosynthesis. A model describing the net effects of these processes on biomass would be useful, but would need to reconcile reported differences in the effects of night and day temperature on plant productivity. In this study, the working hypothesis was that the temperature responses of CO2 assimilation and plant development rates were divergent, and that their net effects could explain observed differences in biomass accumulation. In wheat (Triticum aestivum) plants, we followed the temperature responses of photosynthesis, respiration and leaf elongation, and confirmed that their responses diverged. We measured the amount of carbon assimilated per "unit of plant development" in each scenario and compared it to the biomass that accumulated in growing leaves and grains. Our results suggested that, up to a temperature optimum, the rate of any developmental process increased with temperature more rapidly than that of CO2 assimilation and that this discrepancy, summarised by the CO2 assimilation rate per unit of plant development, could explain the observed reductions in biomass accumulation in plant organs under high temperatures. The model described the effects of night and day temperature equally well, and offers a simple framework for describing the effects of temperature on plant growth. Published by Oxford University Press on behalf of the Annals of Botany Company.

  6. Effects of winter temperature and summer drought on net ecosystem exchange of CO2 in a temperate peatland

    Science.gov (United States)

    Helfter, Carole; Campbell, Claire; Dinsmore, Kerry; Drewer, Julia; Coyle, Mhairi; Anderson, Margaret; Skiba, Ute; Nemitz, Eiko; Billett, Michael; Sutton, Mark

    2014-05-01

    Northern peatlands are one of the most important global sinks of atmospheric carbon dioxide (CO2); their ability to sequester C is a natural feedback mechanism controlled by climatic variables such as precipitation, temperature, length of growing season and period of snow cover. In the UK it has been predicted that peatlands could become a net source of carbon in response to climate change with climate models predicting a rise in global temperature of ca. 3oC between 1961-1990 and 2100. Land-atmosphere exchange of CO2in peatlands exhibits marked seasonal and inter-annual variations, which have significant short- and long-term effects on carbon sink strength. Net ecosystem exchange (NEE) of CO2 has been measured continuously by eddy-covariance (EC) at Auchencorth Moss (55° 47'32 N, 3° 14'35 W, 267 m a.s.l.), a temperate peatland in central Scotland, since 2002. Auchencorth Moss is a low-lying, ombrotrophic peatland situated ca. 20 km south-west of Edinburgh. Peat depth ranges from 5 m and the site has a mean annual precipitation of 1155 mm. The vegetation present within the flux measurement footprint comprises mixed grass species, heather and substantial areas of moss species (Sphagnum spp. and Polytrichum spp.). The EC system consists of a LiCOR 7000 closed-path infrared gas analyser for the simultaneous measurement of CO2 and water vapour and of a Gill Windmaster Pro ultrasonic anemometer. Over the 10 year period, the site was a consistent yet variable sink of CO2 ranging from -34.1 to -135.9 g CO2-C m-2 yr-1 (mean of -69.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing seasons and mean winter air temperature explained 93% of the variability in summertime sink strength, indicating a phenological memory-effect. Plant development and productivity were stunted by colder winters causing a net reduction in the annual carbon sink strength of this peatland where autotrophic processes are thought to be

  7. Effect of elevated CO2 and temperature on abiotic and biologically-driven basalt weathering and C sequestration

    Science.gov (United States)

    Juarez, Sabrina; Dontsova, Katerina; Le Galliard, Jean-François; Chollet, Simon; Llavata, Mathieu; Massol, Florent; Cros, Alexis; Barré, Pierre; Gelabert, Alexandre; Daval, Damien; Corvisier, Jérôme; Troch, Peter; Barron-Gafford, Greg; Van Haren, Joost; Ferrière, Régis

    2016-04-01

    Weathering of primary silicates is one of the mechanisms involved in carbon removal from the atmosphere, affecting the carbon cycle at geologic timescales with basalt significantly contributing to the global weathering CO2 flux. Mineral weathering can be enhanced by microbiota and plants. Increase in both temperature and amount of CO2 in the atmosphere can directly increase weathering and can also affect weathering through impact on biological systems. This would result in possible negative feedback on climate change. The goal of this research was to quantify direct and indirect effects of temperature and elevated CO2 on basalt weathering and carbon sequestration. In order to achieve this goal we performed controlled-environment mesocosm experiments at Ecotron Ile-de-France (France). Granular basalt collected in Flagstaff (AZ, USA) was exposed to rainfall at equilibrium with two different CO2 concentrations in the air, ambient (400 ppm) and elevated (800 ppm); and kept at two climate regimes, with ambient and elevated (+ 4° C) temperature. Four biological treatments were superimposed on this design: a plant-free control; N-fixing grass (Alfalfa, Medicago sativa), N-fixing tree (Velvet mesquite, Prosopis velutina); and grass that does not form symbiotic relationships with N fixers (Green Sprangletop, Leptochloa dubia). All used basalt had native microbial community. Mesocosms were equipped with solution and gas samplers. To monitor biogenic and lithogenic weathering product concentrations, soil solution samples were collected under vacuum after each rainfall event and analyzed to determine pH, electrical conductivity, major and trace elements concentrations, anions concentrations, and aqueous phase organic matter chemistry. Soil gases were monitored for CO2 using porous Teflon gas samplers connected to the Vaisala probes. Plant biomass was collected at the end of the experiment to determine dry weight, as well as removal of N and lithogenic elements by the plants

  8. Dual-Channel, Molecular-Sieving Core/Shell ZIF@MOF Architectures as Engineered Fillers in Hybrid Membranes for Highly Selective CO2Separation.

    Science.gov (United States)

    Song, Zhuonan; Qiu, Fen; Zaia, Edmond W; Wang, Zhongying; Kunz, Martin; Guo, Jinghua; Brady, Michael; Mi, Baoxia; Urban, Jeffrey J

    2017-11-08

    A novel core/shell porous crystalline structure was prepared using a large pore metal organic framework (MOF, UiO-66-NH 2 , pore size, ∼ 0.6 nm) as core surrounded by a small pore zeolitic imidazolate framework (ZIF, ZIF-8, pore size, ∼ 0.4 nm) through a layer-by-layer deposition method and subsequently used as an engineered filler to construct hybrid polysulfone (PSF) membranes for CO 2 capture. Compared to traditional fillers utilizing only one type of porous material with rigid channels (either large or small), our custom designed core/shell fillers possess clear advantages via pore engineering: the large internal channels of the UiO-66-NH 2 MOFs create molecular highways to accelerate molecular transport through the membrane, while the thin shells with small pores (ZIF-8) or even smaller pores generated at the interface by the imperfect registry between the overlapping pores of ZIF and MOF enhance molecular sieving thus serving to distinguish slightly larger N 2 molecules (kinetic diameter, 0.364 nm) from smaller CO 2 molecules (kinetic diameter, 0.33 nm). The resultant core/shell ZIF@MOF and as-prepared hybrid PSF membranes were characterized by transmission electron microscopy, X-ray diffraction, wide-angle X-ray scattering, scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, and contact angle tests. The dependence of the separation performance of the membranes on the MOF/ZIF ratio was also studied by varying the number of layers of ZIF coatings. The integrated PSF-ZIF@MOF hybrid membrane (40 wt % loading) with optimized ZIF coating cycles showed improved hydrophobicity and excellent CO 2 separation performance by simultaneously increasing CO 2 permeability (CO 2 permeability of 45.2 barrer, 710% higher than PSF membrane) and CO 2 /N 2 selectivity (CO 2 /N 2 selectivity of 39, 50% higher than PSF membrane), which is superior to most reported hybrid PSF membranes. The strategy of using

  9. Shifting from right to left: the combined effect of elevated CO2 and temperature on behavioural lateralization in a coral reef fish.

    Directory of Open Access Journals (Sweden)

    Paolo Domenici

    Full Text Available Recent studies have shown that elevated CO2 can affect the behaviour of larval and juvenile fishes. In particular, behavioural lateralization, an expression of brain functional asymmetries, is affected by elevated CO2 in both coral reef and temperate fishes. However, the potentially interacting effects of rising temperatures and CO2 on lateralization are unknown. Here, we tested the combined effect of near-future elevated-CO2 concentrations (930 µatm and temperature variation on behavioural lateralization of a marine damselfish, Pomacentrus wardi. Individuals exposed to one of four treatments (two CO2 levels and two temperatures were observed in a detour test where they made repeated decisions about turning left or right. Individuals exposed to current CO2 and ambient temperature levels showed a significant right-turning bias at the population level. This biased was reversed (i.e. to the left side in fish exposed to the elevated-CO2 treatment. Increased temperature attenuated this effect, resulting in lower values of relative lateralization. Consequently, rising temperature and elevated CO2 may have different and interactive effects on behavioural lateralization and therefore future studies on the effect of climate change on brain functions need to consider both these critical variables in order to assess the potential consequences for the ecological interactions of marine fishes.

  10. Reducing CO2 emissions in temperature-controlled road transportation using the LDVRP model

    NARCIS (Netherlands)

    Stellingwerf, Helena M.; Kanellopoulos, Argyris; Vorst, van der Jack G.A.J.; Bloemhof, Jacqueline M.

    2018-01-01

    Temperature-controlled transport is needed to maintain the quality of products such as fresh and frozen foods and pharmaceuticals. Road transportation is responsible for a considerable part of global emissions. Temperature-controlled transportation exhausts even more emissions than ambient

  11. Effects of temperature and CO2 during late incubation on broiler chicken development

    NARCIS (Netherlands)

    Maatjens, C.M.

    2016-01-01

    Incubation conditions need to be adjusted to meet embryonic requirements to obtain optimal chick quality and hatchability. Eggshell temperature (EST) can be used as a non- invasive method to determine embryo temperature. A high EST of 38.9°C during the second or third week of incubation

  12. Simple additive effects are rare: a quantitative review of plant biomass and soil process responses to combined manipulations of CO2 and temperature

    DEFF Research Database (Denmark)

    Dieleman, Wouter I.J.; Vicca, Sara; Dijkstra, Feike A.

    2012-01-01

    In recent years, increased awareness of the potential interactions between rising atmospheric CO2 concentrations ([ CO2 ]) and temperature has illustrated the importance of multifactorial ecosystem manipulation experiments for validating Earth System models. To address the urgent need for increased...... understanding of responses in multifactorial experiments, this article synthesizes how ecosystem productivity and soil processes respond to combined warming and [ CO2 ] manipulation, and compares it with those obtained in single factor [ CO2 ] and temperature manipulation experiments. Across all combined...... and the [ CO2 ]-only treatments elicited larger stimulation of fine root biomass than of aboveground biomass, consistently stimulated soil respiration, and decreased foliar nitrogen (N) concentration. Nonetheless, mineral N availability declined less in the combined treatment than in the [ CO2 ]-only treatment...

  13. Simple additive effects are rare: a quantitative review of plant biomass and soil process responses to combined manipulations of CO2 and temperature

    DEFF Research Database (Denmark)

    Dieleman, Wouter I. J.; Vicca, Sara; Dijkstra, Feike A.

    2012-01-01

    In recent years, increased awareness of the potential interactions between rising atmospheric CO2 concentrations ([ CO2 ]) and temperature has illustrated the importance of multifactorial ecosystem manipulation experiments for validating Earth System models. To address the urgent need for increased...... understanding of responses in multifactorial experiments, this article synthesizes how ecosystem productivity and soil processes respond to combined warming and [ CO2 ] manipulation, and compares it with those obtained in single factor [ CO2 ] and temperature manipulation experiments. Across all combined...... and the [ CO2 ]‐only treatments elicited larger stimulation of fine root biomass than of aboveground biomass, consistently stimulated soil respiration, and decreased foliar nitrogen (N) concentration. Nonetheless, mineral N availability declined less in the combined treatment than in the [ CO2 ]‐only treatment...

  14. 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

  15. Metabolic Heat Regenerated Temperature Swing Adsorption for CO2, Thermal and Humidity Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is proposed for a Portable Life Support System to remove and reject heat and carbon dioxide...

  16. Effect of temperature on coke properties and CO2 reactivity under laboratory conditions and in an experimental blast furnace

    OpenAIRE

    Hilding, Tobias; Kazuberns, Kelli; Gupta, Sushil; Sahajwalla, Veena; Sakurovs, Richard; Björkman, Bo; Wikström, Jan-Olov

    2005-01-01

    Physical and chemical properties of coke samples excavated from LKAB's Experimental Blast Furnace (EBF) at MEFOS in Lulea, Sweden were characterized. A thermal annealing study the raw coke used in the EBF was also conducted in a horizontal furnace in a neutral environment at a range of temperatures up to 1650DGC. Carbon crystallite height of the EBF coke and of the cokes treated in the laboratory furnace were measured by XRD while mineral phases were characterized by using SEM/EDS. The CO2 re...

  17. A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101.

    Directory of Open Access Journals (Sweden)

    Tobias G Boatman

    Full Text Available Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 - 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin but had no effect on the optimum temperature (Topt at which growth was maximal or the maximum temperature tolerance limit (Tmax; low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2. In the context of environmental change, our results suggest that the (i nutrient replete growth rate of Trichodesmium IMS101 would have been severely limited by low pCO2 at the last glacial maximum (LGM, (ii future increases in pCO2 will increase growth rates in areas where temperature ranges between Tmin to Topt, but will have negligible effect at temperatures between Topt and Tmax, (iii areal increase of warm surface waters (> 18°C has allowed the geographic range to increase significantly from the LGM to present and that the range will continue to expand to higher latitudes with continued warming, but (iv continued global warming may exclude Trichodesmium spp. from some tropical regions by 2100 where temperature exceeds Topt.

  18. Photosynthesis and Rubisco kinetics in spring wheat and meadow fescue under conditions of simulated climate change with elevated CO2 and increased temperatures

    Directory of Open Access Journals (Sweden)

    K. HAKALA

    2008-12-01

    Full Text Available Spring wheat (Triticum aestivum L.cv.Polkkaand meadow fescue (Festuca pratensis Hudson cv. Kalevicwere grown in ambient and elevated (700 µl l -1 carbon dioxide concentration both at present ambient temperatures and at temperatures 3°C higher than at present simulating a future climate.The CO2 concentrations were elevated in large (3 m in diameteropen top chambers and the temperatures in a greenhouse built over the experimental field.The photosynthetic rate of both wheat and meadow fescue was 31 –37%higher in elevated carbon dioxide (eCO2 than in ambient CO 2 (aCO2 throughout the growing season.The enhancement in wheat photosynthesis in eCO2 declined 10 –13 days before yellow ripeness,at which point the rate of photosynthesis in both CO 2 treatments declined.The stomatal conductance of wheat and meadow fescue was 23–36% lower in eCO2 than in aCO2 .The amount and activity of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco in wheat were lower under conditions of eCO2 ,except at elevated temperatures in 1993 when there was a clear yield increase.There was no clear change in the amount and activity of Rubisco in meadow fescue under eCO2 at either elevated or ambient temperature.This suggests that adaptation to elevated CO2 at biochemical level occurs only when there is insufficient sink for photosynthetic products.While the sink size of wheat can be increased only by introducing new,more productive genotypes,the sink size of meadow fescue can be regulated by fitting the cutting schedule to growth.;

  19. Interfacial Design of Ternary Mixed Matrix Membranes Containing Pebax 1657/Silver-Nanopowder/[BMIM][BF4] for Improved CO2 Separation Performance.

    Science.gov (United States)

    Ghasemi Estahbanati, Ehsan; Omidkhah, Mohammadreza; Ebadi Amooghin, Abtin

    2017-03-22

    In this research, Pebax1657 as an organic phase and silver nanoparticles as an inorganic phase were used for preparation of binary mixed matrix membranes (MMMs). Silver nanoparticles as a filler could enter the polymer chains and enhance the gas permeability by increasing the fractional free volume of membranes. Afterward, ternary MMMs were fabricated by addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid, in order to have better polymer/filler adhesion and eliminate interfacial defects and nonselective voids. In addition, positively polarized silver nanoparticles in the presence of the IL could interact with PEO segment of the polymer and increase the CO2 affinity of membranes, which results in increasing the CO2/light gases permselectivity of MMMs. Gas permeation properties of MMMs were studied at a temperature of 35 °C and operating pressures from 2 to 10 bar. Moreover, fabricated membranes were characterized by fourier transform infrared-attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The analysis revealed that there is a proper adhesion between positively charged surface of nanoparticles and the polymer, and both filler and IL decrease the crystallinity of the membranes, which could enhance the polar gas transport properties. Gas permeation results showed significant enhancement in CO2 permeability (325 Barrer) for binary membrane (Pebax 1657/1%Ag) at 35 °C and 10 bar. Moreover, ternary MMM (Pebax 1657/0.5%Ag/50%IL) encountered significant increase in both permeability and selectivity in comparison with neat membrane. Indeed, the CO2 permeability increased from 110 Barrer to 180 (about 64%). Moreover, the related CO2/CH4 and CO2/N2 selectivities were increased from 20.8 to 61.0 (more than 193%) and from 78.6 to 187.5 (about 139%), respectively.

  20. Degradation of metaflumizone in soil: impact of varying moisture, light, temperature, atmospheric CO2 level, soil type and soil sterilization.

    Science.gov (United States)

    Chatterjee, Niladri Sekhar; Gupta, Suman; Varghese, Eldho

    2013-01-01

    Soil is a major sink for the bulk of globally used pesticides. Hence, fate of pesticides in soil under the influence of various biotic and abiotic factors becomes important for evaluation of stability and safety. This paper presents the impact of varying moisture, light, temperature, atmospheric CO(2) level, soil type and soil sterilization on degradation of metaflumizone, a newly registered insecticide in India. Degradation of metaflumizone in soil followed the first order reaction kinetics and its half life values varied from ~20 to 150 d. Under anaerobic condition, degradation of metaflumizone was faster (t(½) 33.4 d) compared to aerobic condition (t(½) 50.1 d) and dry soil (t(½) 150.4 d). Under different light exposures, degradation was the fastest under UV light (t(½) 27.3 d) followed by Xenon light (t(½) 43 d) and dark condition (t(½) 50.1 d). Degradation rate of metaflumizone increased with temperature and its half life values ranged from 30.1 to 100.3d. Elevated atmospheric CO(2) level increased the degradation in soil (t(½) 20.1-50.1 d). However, overall degradation rate was the fastest at 550 ppm atmospheric CO(2) level, followed by 750 ppm and ambient level (375 ppm). Degradation of metaflumizone was faster in Oxisol (pH 5.2, Total Organic Carbon 1.2%) compared to Inceptisol (pH 8.15, TOC 0.36%). In sterile soil, only 5% dissipation of initial concentration was observed after 90 d of sampling. Under various conditions, 4-cyanobenzoic acid (0.22-1.86 mg kg(-1)) and 4-trifluoromethoxy aniline (0.21-1.23 mg kg(-1)) were detected as major degradation products. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Flame temperature trends in reacting vanadium and tungsten ethoxide fluid sprays during CO2-laser pyrolysis

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2011-09-01

    Full Text Available in these sprays suggest that these are electronic heat capacities rather than lattice heat capacities; enthalpies are also obtained. Our temperature-laser power trends are in agreement with previous findings. The damping coefficients and hence the saturation...

  2. A reconstruction of temperature, ice volume and atmospheric CO2 over the past 40 million years

    NARCIS (Netherlands)

    de Boer, B.|info:eu-repo/dai/nl/304023183

    2012-01-01

    Knowledge on past climate change largely emerges from sediment records drilled from the ocean floor and ice-core records from the Antarctic and Greenland ice sheets. From these records proxy data is obtained indicating changes in, for example, temperature, sea level and greenhouse gas

  3. Synergistic effect of elevated temperature, pCO2 and nutrients on marine biofilm

    Digital Repository Service at National Institute of Oceanography (India)

    Baragi, L.V.; Anil, A.C.

    Natural marine biofilms provide signatures of the events that occur over a period of time and can be used as bioindicators of environmental changes. Hence, the effects of temperature (30 and 34 °C), pCO2 (400 and 1500 microatm...

  4. Quantification of temperature, CO2, and light effects on crop photosynthesis as a basis for model-based greenhouse climate control

    NARCIS (Netherlands)

    Körner, O.; Heuvelink, E.; Niu, Q.

    2009-01-01

    Detailed measurements of crop photosynthesis at supra-optimal temperatures and high CO2 levels, to validate models for use in model-based greenhouse climate control, are still lacking. We performed CO2 gas exchange measurements to estimate gross crop photosynthesis (Pgc) from measured net crop gas

  5. Simultaneous Measurements of CO2 Concentration and Temperature profiles using 1.6 μm DIAL in the Lower-Atmosphere

    Science.gov (United States)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2016-12-01

    High-accurate vertical carbon dioxide (CO2) profiles are highly desirable in the inverse method to improve quantification and understanding of the global sink and source of CO2, and also global climate change. We have developed a ground based 1.6μm differential absorption lidar (DIAL) to achieve measurements of vertical CO2 profiles in the atmosphere. As the spectra of absorption lines of any molecules are influenced basically by the temperature and pressure in the atmosphere, it is important to measure them simultaneously so that the better accuracy of the DIAL measurement is realized. The barometric formula can derive atmospheric pressure of each altitude using atmospheric pressure of ground level at the lidar site. Comparison of atmospheric pressure prlofiles calculated from this equation and those obtained from radiosonde observations at Tateno, Japan are consisted within 0.2 % below 3 km altitude. So, we have developed a 1.6 μm CO2 DIAL system for simultaneous measurements of the CO2 concentration and temperature profiles in the lower-atmosphere. Laser beams of three wavelengths around a CO2 absorption spectrum is transmitted alternately to the atmosphere. Moreover, the value of the retrieved CO2 concentration will be improved remarkably by processing the iteration assignment of CO2 concentration and temperature, which measured by these DIAL techniques. We have acheived vertical CO2 concentration and temperature profile from 0.5 to 2.0 km altitude by this DIAL system. In the next step, we will use this high accuracy CO2 concentration profile and back-trajectory analysis for the behavior analysis of the CO2 mass. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency.

  6. H2O and CO2 vapor pressure measurements at temperatures relevant to the middle atmosphere of Earth and Mars

    Science.gov (United States)

    Nachbar, M.; Duft, D.; Leisner, T.

    2017-09-01

    Measurements of the vapor pressure of H2O and CO2 at temperatures relevant to the middle atmosphere of Earth and Mars are rare but important in order to describe cloud formation and ice particle growth processes. In this contribution we present a novel technique for measuring the vapor pressure of condensable gases by analyzing the depositional growth rates on free nanoparticles at high supersaturation. The method is applied to measure the vapor pressure of CO2 between 75K and 85K. By comparison with previous measurements and parameterizations we are able to show the excellent functionality of the method. In addition, the method is used to measure the vapor pressure over H2O ice between 135K and 160K. We show that the vapor pressure of so called stacking disordered ice Isd deposited at temperatures below 160K is significantly higher compared to hexagonal ice Ih. The consequences for ice cloud formation in the atmosphere of Earth and Mars will be discussed.

  7. Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets

    Energy Technology Data Exchange (ETDEWEB)

    Menon, Surabi; Akbari, Hashem; Mahanama, Sarith; Sednev, Igor; Levinson, Ronnen

    2010-02-12

    The two main forcings that can counteract to some extent the positive forcings from greenhouse gases from pre-industrial times to present-day are the aerosol and related aerosol-cloud forcings, and the radiative response to changes in surface albedo. Here, we quantify the change in radiative forcing and land surface temperature that may be obtained by increasing the albedos of roofs and pavements in urban areas in temperate and tropical regions of the globe by 0.1. Using the catchment land surface model (the land model coupled to the GEOS-5 Atmospheric General Circulation Model), we quantify the change in the total outgoing (outgoing shortwave+longwave) radiation and land surface temperature to a 0.1 increase in urban albedos for all global land areas. The global average increase in the total outgoing radiation was 0.5 Wm{sup -2}, and temperature decreased by {approx}0.008 K for an average 0.003 increase in surface albedo. These averages represent all global land areas where data were available from the land surface model used and are for the boreal summer (June-July-August). For the continental U.S. the total outgoing radiation increased by 2.3 Wm{sup -2}, and land surface temperature decreased by {approx}0.03 K for an average 0.01 increase in surface albedo. Based on these forcings, the expected emitted CO{sub 2} offset for a plausible 0.25 and 0.15 increase in albedos of roofs and pavements, respectively, for all global urban areas, was found to be {approx} 57 Gt CO{sub 2}. A more meaningful evaluation of the impacts of urban albedo increases on global climate and the expected CO{sub 2} offsets would require simulations which better characterizes urban surfaces and represents the full annual cycle.

  8. High temperature inorganic membranes for separating hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1995-08-01

    Effort has continued to accumulate data on the transport of gases over the temperature range from room temperature to 275{degrees}C with inorganic membranes having a range of pore radii from approximately 0.25 nm to 3 mn. An experimental alumina membrane having an estimated mean pore radius of 0.25 nm has been fabricated and tested. Extensive testing of this membrane indicated that the separation factor for helium and carbon tetrafluoride at 250{degrees}C was 59 and the extrapolated high temperature separation factor was 1,193. For safety reasons, earlier flow measurements concentrated on helium, carbon dioxide, and carbon tetrafluoride. New data have been acquired with hydrogen to verify the agreement with the other gases. During the measurements with hydrogen, it was noted that a considerable amount of moisture was present in the test gas. The source of this moisture and its effect on permeance was examined. Improvements were implemented to the flow test system to minimize the water content of the hydrogen test gas, and subsequent flow measurements have shown excellent results with hydrogen. The extrapolation of separation factors as a function of temperature continues to show promise as a means of using the hard sphere model to determine the pore size of membranes. The temperature dependence of helium transport through membranes appears to be considerably greater than other gases for the smallest pore sizes. The effort to extend temperature dependence to the hard sphere model continues to be delayed, primarily because of a lack of adequate adsorption data.

  9. Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

    KAUST Repository

    Babarao, Ravichandar

    2010-07-06

    The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.

  10. Effects of elevated CO2 and temperature on yield and fruit quality of strawberry (Fragaria × ananassa Duch.) at two levels of nitrogen application.

    Science.gov (United States)

    Sun, Peng; Mantri, Nitin; Lou, Heqiang; Hu, Ya; Sun, Dan; Zhu, Yueqing; Dong, Tingting; Lu, Hongfei

    2012-01-01

    We investigated if elevated CO(2) could alleviate the negative effect of high temperature on fruit yield of strawberry (Fragaria × ananassa Duch. cv. Toyonoka) at different levels of nitrogen and also tested the combined effects of CO(2), temperature and nitrogen on fruit quality of plants cultivated in controlled growth chambers. Results show that elevated CO(2) and high temperature caused a further 12% and 35% decrease in fruit yield at low and high nitrogen, respectively. The fewer inflorescences and smaller umbel size during flower induction caused the reduction of fruit yield at elevated CO(2) and high temperature. Interestingly, nitrogen application has no beneficial effect on fruit yield, and this may be because of decreased sucrose export to the shoot apical meristem at floral transition. Moreover, elevated CO(2) increased the levels of dry matter-content, fructose, glucose, total sugar and sweetness index per dry matter, but decreased fruit nitrogen content, total antioxidant capacity and all antioxidant compounds per dry matter in strawberry fruit. The reduction of fruit nitrogen content and antioxidant activity was mainly caused by the dilution effect of accumulated non-structural carbohydrates sourced from the increased net photosynthetic rate at elevated CO(2). Thus, the quality of strawberry fruit would increase because of the increased sweetness and the similar amount of fruit nitrogen content, antioxidant activity per fresh matter at elevated CO(2). Overall, we found that elevated CO(2) improved the production of strawberry (including yield and quality) at low temperature, but decreased it at high temperature. The dramatic fluctuation in strawberry yield between low and high temperature at elevated CO(2) implies that more attention should be paid to the process of flower induction under climate change, especially in fruits that require winter chilling for reproductive growth.

  11. Arctic Sea ice decay simulated for a CO2-induced temperature rise

    Science.gov (United States)

    Parkinson, C. L.; Kellogg, W. W.

    1981-01-01

    A large scale numerical time-dependent model of sea ice that takes into account the heat fluxes in and out of the ice, the seasonal occurrence of snow, and ice motions was used in an experiment to determine the response of the Arctic Ocean ice pack to a warming of the atmosphere. The degree of warming specified is that expected for a doubling of atmospheric carbon dioxide with its associated greenhouse effect, a condition that could occur before the middle of the next century. The results of three 5-year simulations with a warmer atmosphere and varied boundary conditions were: (1) that in the face of a 5 K surface atmospheric temperature increase the ice pack disappeared completely in August and September but reformed in the central Arctic Ocean in mid fall; (2) that the simulations were moderately dependence on assumptions concerning cloud cover; and (3) that even when atmospheric temperature increases of 6-9 K were combined with an order-of-magnitude increase in the upward heat flux from the ocean, the ice still appeared in winter. It should be noted that a year-round ice-free Arctic Ocean has apparently not existed for a million years or more.

  12. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

    Directory of Open Access Journals (Sweden)

    Ricardo Couto

    2015-01-01

    Full Text Available In this work, a supported ionic liquid membrane (SILM was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA] ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2 and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73 for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

  13. Effect temperature of supercritical CO2 fluid extraction on phytochemical analysis and antioxidant activity of Zingiber officinale Roscoe

    Science.gov (United States)

    Sondari, Dewi; Irawadi, Tun Tedja; Setyaningsih, Dwi; Tursiloadi, Silvester

    2017-11-01

    Supercritical fluid extraction of Zingiber officinale Roscoe has been carried out at a pressure of 16 MPa, with temperatures between 20-40 °C, during extraction time of 6 hours and the flow rate of CO2 fluid 5.5 ml/min. The result of supercritical method was compared with the extraction maceration using a mixture of water and ethanol (70% v/v) for 24 hours. The main content in ginger that has a main role as an antioxidant is a gingerol compound that can help neutralize the damaging effects caused by free radicals in the body, as anti-coagulant, and inhibit the occurrence of blood clots. This study aims to determine the effect of temperature on chemical components contained in rough extract of Zingiber officinale Roscoe and its antioxidant activity, total phenol and total flavonoid content. To determine the chemical components contained in the crude extract of Zingiber officinale Roscoe extracted by supercritical fluid and maceration extraction, GC-MS analysis was performed. Meanwhile, the antioxidant activity of the extract was evaluated based on a 2.2-diphenyl-1-picrylhydrazyl (DPPH) free radical damping method. The results of the analysis show that the result of ginger extract by using the supercritical CO2 extraction method has high antioxidant activity than by using maceration method. The highest total phenol content and total flavonoids were obtained on ginger extraction using supercritical CO2 fluid extraction, indicating that phenol and flavonoid compounds contribute to antioxidant activity. Chromatographic analysis showed that the chemical profile of ginger extract containing oxygenated monoterpenes, monoterpene hydrocarbons, sesquiterpene hydrocarbons, oxygenated monoterpene gingerol and esters. In supercritical fluid extraction, the compounds that can be identified at a temperature of 20-40 °C contain 27 compounds, and 11 compounds from the result of maceration extract. The main component of Zingiber officinale Roscoe extracted using supercritical fluid

  14. The acclimation of photosynthesis and respiration to temperature in the C3 -C4 intermediate Salsola divaricata: induction of high respiratory CO2 release under low temperature.

    Science.gov (United States)

    Gandin, Anthony; Koteyeva, Nuria K; Voznesenskaya, Elena V; Edwards, Gerald E; Cousins, Asaph B

    2014-11-01

    Photosynthesis in C(3) -C(4) intermediates reduces carbon loss by photorespiration through refixing photorespired CO(2) within bundle sheath cells. This is beneficial under warm temperatures where rates of photorespiration are high; however, it is unknown how photosynthesis in C(3) -C(4) plants acclimates to growth under cold conditions. Therefore, the cold tolerance of the C(3) -C(4) Salsola divaricata was tested to determine whether it reverts to C(3) photosynthesis when grown under low temperatures. Plants were grown under cold (15/10 °C), moderate (25/18 °C) or hot (35/25 °C) day/night temperatures and analysed to determine how photosynthesis, respiration and C(3) -C(4) features acclimate to these growth conditions. The CO(2) compensation point and net rates of CO(2) assimilation in cold-grown plants changed dramatically when measured in response to temperature. However, this was not due to the loss of C(3) -C(4) intermediacy, but rather to a large increase in mitochondrial respiration supported primarily by the non-phosphorylating alternative oxidative pathway (AOP) and, to a lesser degree, the cytochrome oxidative pathway (COP). The increase in respiration and AOP capacity in cold-grown plants likely protects against reactive oxygen species (ROS) in mitochondria and photodamage in chloroplasts by consuming excess reductant via the alternative mitochondrial respiratory electron transport chain. © 2014 John Wiley & Sons Ltd.

  15. Temporal and spatial temperature distribution in the glabrous skin of rats induced by short-pulse CO2 laser

    Science.gov (United States)

    Lu, Pen-Li; Hsu, Shu-Shen; Tsai, Meng-Li; Jaw, Fu-Shan; Wang, An-Bang; Yen, Chen-Tung

    2012-11-01

    Pain is a natural alarm that aids the body in avoiding potential danger and can also present as an important indicator in clinics. Infrared laser-evoked potentials can be used as an objective index to evaluate nociception. In animal studies, a short-pulse laser is crucial because it completes the stimulation before escape behavior. The objective of the present study was to obtain the temporal and spatial temperature distributions in the skin caused by the irradiation of a short-pulse laser. A fast speed infrared camera was used to measure the surface temperature caused by a CO2 laser of different durations (25 and 35 ms) and power. The measured results were subsequently implemented with a three-layer finite element model to predict the subsurface temperature. We found that stratum corneum was crucial in the modeling of fast temperature response, and escape behaviors correlated with predictions of temperature at subsurface. Results indicated that the onset latency and duration of activated nociceptors must be carefully considered when interpreting physiological responses evoked by infrared irradiation.

  16. Are global warming and ocean acidification conspiring against marine ectotherms? A meta-analysis of the respiratory effects of elevated temperature, high CO2 and their interaction.

    Science.gov (United States)

    Lefevre, Sjannie

    2016-01-01

    With the occurrence of global change, research aimed at estimating the performance of marine ectotherms in a warmer and acidified future has intensified. The concept of oxygen- and capacity-limited thermal tolerance, which is inspired by the Fry paradigm of a bell-shaped increase-optimum-decrease-type response of aerobic scope to increasing temperature, but also includes proposed negative and synergistic effects of elevated CO2 levels, has been suggested as a unifying framework. The objectives of this meta-analysis were to assess the following: (i) the generality of a bell-shaped relationship between absolute aerobic scope (AAS) and temperature; (ii) to what extent elevated CO2 affects resting oxygen uptake MO2rest and AAS; and (iii) whether there is an interaction between elevated temperature and CO2. The behavioural effects of CO2 are also briefly discussed. In 31 out of 73 data sets (both acutely exposed and acclimated), AAS increased and remained above 90% of the maximum, whereas a clear thermal optimum was observed in the remaining 42 data sets. Carbon dioxide caused a significant rise in MO2rest in only 18 out of 125 data sets, and a decrease in 25, whereas it caused a decrease in AAS in four out of 18 data sets and an increase in two. The analysis did not reveal clear evidence for an overall correlation with temperature, CO2 regime or duration of CO2 treatment. When CO2 had an effect, additive rather than synergistic interactions with temperature were most common and, interestingly, they even interacted antagonistically on MO2rest and AAS. The behavioural effects of CO2 could complicate experimental determination of respiratory performance. Overall, this meta-analysis reveals heterogeneity in the responses to elevated temperature and CO2 that is not in accordance with the idea of a single unifying principle and which cannot be ignored in attempts to model and predict the impacts of global warming and ocean acidification on marine ectotherms.

  17. Simultaneous sensing of temperature, CO, and CO2 in a scramjet combustor using quantum cascade laser absorption spectroscopy

    Science.gov (United States)

    Spearrin, R. M.; Goldenstein, C. S.; Schultz, I. A.; Jeffries, J. B.; Hanson, R. K.

    2014-07-01

    A mid-infrared laser absorption sensor was developed for gas temperature and carbon oxide (CO, CO2) concentrations in high-enthalpy, hydrocarbon combustion flows. This diagnostic enables non-intrusive, in situ measurements in harsh environments produced by hypersonic propulsion ground test facilities. The sensing system utilizes tunable quantum cascade lasers capable of probing the fundamental mid-infrared absorption bands of CO and CO2 in the 4-5 µm wavelength domain. A scanned-wavelength direct absorption technique was employed with two lasers, one dedicated to each species, free-space fiber-coupled using a bifurcated hollow-core fiber for remote light delivery on a single line of sight. Scanned-wavelength modulation spectroscopy with second-harmonic detection was utilized to extend the dynamic range of the CO measurement. The diagnostic was field-tested on a direct-connect scramjet combustor for ethylene-air combustion. Simultaneous, laser-based measurements of carbon monoxide and carbon dioxide provide a basis for evaluating combustion completion or efficiency with temporal and spatial resolution in practical hydrocarbon-fueled engines.

  18. Effects of nitrogen fertilizer sources and temperature on soil CO2 efflux in Italian ryegrass crop under Mediterranean conditions

    Directory of Open Access Journals (Sweden)

    Roberto Lai

    2012-06-01

    Full Text Available We report the results of a study that aimed to assess the dynamics of total and heterotrophic soil respiration and its relationships with soil temperature or soil moisture of an Italian ryegrass haycrop managed with different nitrogen (N fertilizer sources. The field experiment was carried out in the Nitrate Vulnerable Zone of the dairy district of Arborea, a reclaimed wetland in central-western Sardinia, Italy. This is an area characterized by sandy soils, shallow water table and intensive dairy cattle farming systems. Italian ryegrass is grown for hay production in the context of a double cropping rotation with silage maize. We analyzed the effects of N fertilizer treatments on soil carbon dioxide (CO2 efflux, soil water content and soil temperature: i farmyard manure; ii cattle slurry; iii mineral fertilizer; iv 70 kg ha-1 from slurry and 60 kg ha-1 from mineral fertilizer that corresponds to the prescriptions of the vulnerable zone management plan. During the monitoring period, soil water content never fell below 8.6% vol., corresponding to approximately -33 kPa matric potential. Total and heterotrophic soil respiration dynamics were both influenced by soil temperature over winter and early spring, reaching a maximum in the first ten days of April in manure and slurry treatments. In the last 30 days of the Italian ryegrass crop cycle, total soil respiration decreased and seemed not to be affected by temperature. The analysis of covariance with soil temperature as covariate showed that average respiration rates were significantly higher under the manure treatment and lower with mineral fertilizer than the slurry and slurry+mineral treatments, but with similar rates of respiration per unit increase of soil temperature for all treatments. The average soil respiration rates were significantly and positively related to the soil carbon (C inputs derived from fertilizers and preceding crop residuals. We concluded that: i the fertilizer source

  19. Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid asymmetric hollow fiber membranes

    NARCIS (Netherlands)

    David, Oana C.; Gorri, Daniel; Nijmeijer, Dorothea C.; Ortiz, Inmaculada; Urtiaga, Ane

    2012-01-01

    The application of hollow fiber membranes for the separation of industrial gas mixtures relies on the correct characterization of the permeation of the involved gaseous components through the hollow fiber membranes. Thus, this study is focused on the characterization of the permeation through

  20. Electronic phase separation and high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kivelson, S.A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Emery, V.J. [Brookhaven National Lab., Upton, NY (United States)

    1994-01-11

    The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional.

  1. Tight coupling between atmospheric ρCO2 and temperature change during the Late Triassic: observational evidence for enhanced climate sensitivity in a hothouse state

    Science.gov (United States)

    Knobbe, T.; Schaller, M. F.

    2015-12-01

    Climate sensitivity is the change in global equilibrium surface temperature per doubling of atmospheric ρCO2. Modern climate sensitivity, based on paleoclimate data and fast-feedback processes (Charney sensitivity), is observed to be ~3°C per doubling of CO2. However, Charney sensitivity may not be representative of ice-free hothouse states that have dominated most of Earth history where sensitivity may be higher. Few opportunities exist to empirically determine climate sensitivity during a hothouse state based on contemporaneous observations of ρCO2 and temperature. Here we present evidence for tight coupling between ρCO2 and temperature during the Late Triassic (end-Norian through Rhaetian) from the Newark basin and Lagonegro/Sicani basins, respectively. Detailed magnetostratigraphy and biostratigraphy allows for correlation between the Lagonegro and Sicani basins (Italy), which are magnetostratigraphically correlated to the Newark basin. Temperature is calculated from δ18O values of conodont apatite published from the Lagonegro and Sicani basins, while ρCO2 estimates are from pedogenic carbonates in the Newark basin. We find a distinct rise and subsequent fall in atmospheric ρCO2 that is precisely mirrored by a contemporaneous rise and fall in temperature. Between 212-209 Ma, we observe a concomitant increase in ρCO2 (1900 to 4800 ppm) and temperature (20 to 27°C), followed by a more protracted concomitant decrease in atmospheric ρCO2 (4800 to 2200 ppm) and temperature (27 to 21°C) from 209-202 Ma. We use simple numerical methods to calculate climate sensitivity for the Late Triassic from these complementary data sets and find that sensitivity through both a doubling and subsequent halving of pCO2 are on the order of 5°C, in close agreement with empirically based model assessments from younger sections. We note sensitivities as high as 7°C/doubling are observed when using the lowest pCO2 estimate allowed by the formal error window assigned to the

  2. A supermolecular building layer approach for gas separation and storage applications: the eea and rtl MOF platforms for CO 2 capture and hydrocarbon separation

    KAUST Repository

    Chen, Zhijie

    2015-02-11

    The supermolecular building layer (SBL) approach was employed to deliberately synthesize five novel metal–organic frameworks (1–5) with an exposed array of amide or amine functionalities within their pore system. The ability to decorate the pores with nitrogen donor moieties offers potential to evaluate/elucidate the structure–adsorption property relationship. Two MOF platforms, eea-MOF and rtl-MOF, based on pillaring of kgm-a or sql-a layers with heterofunctional 3-connected organic building blocks were targeted and constructed to purposely introduce and expose the desired amide or amine functionalities. Interestingly, gas adsorption properties of eea-MOF-4 (1) and eea-MOF-5 (2) showed that by simply altering the nitrogen donor position within the ligand, it is possible to relatively reduce the pore size of the related eea-MOF material and subsequently increase the associated CO2 uptake. The slightly confined pore space in 2, relative to 1, has enabled an enhancement of the pore local charge density and thus the observed relative increase in the CO2 and H2 isosteric heat of adsorption (Qst). In addition, light hydrocarbon adsorption studies revealed that 2 is more selective toward C2H6 and C3H8 over CH4 than 1, as exemplified for C2H6 : CH4 (5 : 95) or C3H8 : CH4 (5 : 95) binary gas mixtures.

  3. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  4. Effect of the annealing temperature on dynamic and structural properties of Co2FeAl thin films

    Directory of Open Access Journals (Sweden)

    Belmeguenai M.

    2014-07-01

    Full Text Available 10 nm and 50 nm thick Co2FeAl (CFA thin films have been deposited on thermally oxidized Si(001 substrates by magnetron sputtering using a Tantalum cap layer and were then ex-situ annealed at 415°C, 515°C and 615°C during 15 minutes in vacuum. X-rays diffraction indicates that films CFA are polycrystalline and exhibit an in-plane isotropy growth. Ferromagnetic resonance measurements, using a microstrip line (MS-FMR, reveal a huge interfacial perpendicular magnetic anisotropy and small in-plane uniaxial anisotropy both annealing temperature-dependent. The MS-FMR data also allow concluding that the gyromagnetic factor remains constant and that the exchange stiffness constant increases with annealing temperature. Finally, the FMR linewidth decreases with increasing annealing temperature due to the enhancement of the chemical order, and allow deriving a very low intrinsic damping parameter (1.3×10−3 at 615°C.

  5. Temperature-dependent Gilbert damping of Co2FeAl thin films with different degree of atomic order

    Science.gov (United States)

    Kumar, Ankit; Pan, Fan; Husain, Sajid; Akansel, Serkan; Brucas, Rimantas; Bergqvist, Lars; Chaudhary, Sujeet; Svedlindh, Peter

    2017-12-01

    Half-metallicity and low magnetic damping are perpetually sought for spintronics materials, and full Heusler compounds in this respect provide outstanding properties. However, it is challenging to obtain the well-ordered half-metallic phase in as-deposited full Heusler compound thin films, and theory has struggled to establish a fundamental understanding of the temperature-dependent Gilbert damping in these systems. Here we present a study of the temperature-dependent Gilbert damping of differently ordered as-deposited Co2FeAl full Heusler compound thin films. The sum of inter- and intraband electron scattering in conjunction with the finite electron lifetime in Bloch states governs the Gilbert damping for the well-ordered phase, in contrast to the damping of partially ordered and disordered phases which is governed by interband electronic scattering alone. These results, especially the ultralow room-temperature intrinsic damping observed for the well-ordered phase, provide fundamental insights into the physical origin of the Gilbert damping in full Heusler compound thin films.

  6. Temperature-, pH- and CO2-Sensitive Poly(N-isopropylacryl amide-co-acrylic acid Copolymers with High Glass Transition Temperatures

    Directory of Open Access Journals (Sweden)

    Yeong-Tarng Shieh

    2016-12-01

    Full Text Available A series of poly(N-isopropylacrylamide-co-acrylic acid (PNIPAAm-co-PAA random copolymers were synthesized through free radical copolymerization in MeOH. The incorporation of the acrylic acid units into PNIPAAm tended to enhance the glass transition temperature (Tg, due to strong intermolecular hydrogen bonding between the amide groups of PNIPAAm and the carboxyl groups of PAA, as observed using 1H nuclear magnetic resonance (NMR and Fourier transform infrared (FTIR spectroscopic analyses. The lower critical solution temperature (LCST increased upon increasing the pH of the aqueous solution containing PNIPAAm-co-PAA because the COOH groups of the PAA segment dissociated into COO− groups, enhancing the solubility of the copolymer. In addition, high-pressure differential scanning calorimetry revealed that the LCSTs of all the aqueous solutions of the copolymers decreased upon increasing the pressure of CO2, suggesting that CO2 molecules had displaced H2O molecules around the polar CONH and COOH groups in PNIPAAm-co-PAA, thereby promoting the hydrophobicity of the copolymers in the aqueous solution. In addition, the values of Tg of a film sample increased upon treatment with supercritical CO2, implying that intermolecular interactions in the copolymer had been enhanced after such treatment.

  7. Development of Highly Durable and Reactive Regenerable Magnesium-Based Sorbents for CO2 Separation in Coal Gasification Process

    Energy Technology Data Exchange (ETDEWEB)

    Javad Abbasian; Armin Hassanzadeh Khayyat; Rachid B. Slimane

    2005-06-01

    The specific objective of this project was to develop physically durable and chemically regenerable MgO-based sorbents that can remove carbon dioxide from raw coal gas at operating condition prevailing in IGCC processes. A total of sixty two (62) different sorbents were prepared in this project. The sorbents were prepared either by various sol-gel techniques (22 formulations) or modification of dolomite (40 formulations). The sorbents were prepared in the form of pellets and in granular forms. The solgel based sorbents had very high physical strength, relatively high surface area, and very low average pore diameter. The magnesium content of the sorbents was estimated to be 4-6 % w/w. To improve the reactivity of the sorbents toward CO{sub 2}, The sorbents were impregnated with potassium salts. The potassium content of the sorbents was about 5%. The dolomite-based sorbents were prepared by calcination of dolomite at various temperature and calcination environment (CO{sub 2} partial pressure and moisture). Potassium carbonate was added to the half-calcined dolomite through wet impregnation method. The estimated potassium content of the impregnated sorbents was in the range of 1-6% w/w. In general, the modified dolomite sorbents have significantly higher magnesium content, larger pore diameter and lower surface area, resulting in significantly higher reactivity compared to the sol-gel sorbents. The reactivities of a number of sorbents toward CO{sub 2} were determined in a Thermogravimetric Analyzer (TGA) unit. The results indicated that at the low CO{sub 2} partial pressures (i.e., 1 atm), the reactivities of the sorbents toward CO{sub 2} are very low. At elevated pressures (i.e., CO{sub 2} partial pressure of 10 bar) the maximum conversion of MgO obtained with the sol-gel based sorbents was about 5%, which corresponds to a maximum CO{sub 2} absorption capacity of less than 1%. The overall capacity of modified dolomite sorbents were at least one order of magnitude

  8. Effect of elevated CO2 concentration and temperature on antioxidant capabilities of multiple generations of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Li, Ning; Li, Yaohua; Zhang, Shize; Fan, Yongliang; Liu, Tongxian

    2017-10-19

    A rise in atmospheric carbon dioxide concentration ([CO2]) and a warming climate are two of the most conspicuous characteristics of global climate change in this century. However, studies addressing the combined impact of rising [CO2] and temperature on herbivore insect physiology are still limited. In this study we investigated the combined effects of elevated [CO2] and temperature on major antioxidative enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidases (POD) and detoxification enzymes of glutathione-S-transferases (GST) and acetylcholinesterase (AChE) in three consecutive generations of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1, commonly known as B biotype) adults. The results indicated that the antioxidant capabilities of B. tabaci differed significantly during different treatments across different generations. Elevated [CO2] markedly increased POD, GST and AChE activities in the first generation, and SOD, CAT and GST activities in the second generation, but reduced POD activity in the third generation at ambient temperature. Under elevated temperature, elevated [CO2] significantly increased GST and AChE activities in the first generation and CAT activity in the third generation, reduced SOD activity in the third generation and reduced AChE activity in the second generation. [CO2], temperature and insect generation interacted to affect the antioxidant capabilities of B. tabaci. These results suggest both that changes in antioxidant capabilities vary in response to either [CO2] or temperature, or a combination of both, leading to oxidative stress and also that antioxidant enzymes play important roles in reducing oxidative damage in B. tabaci. Changes in the exposure of antioxidant compounds over the course of three generations suggest that acclimation and/or adaptation to elevated [CO2] and temperature may have occurred. This study represents the first comprehensive report on the antioxidant defense mechanism in successive multiple

  9. Response to multi-generational selection under elevated [CO2] in two temperature regimes suggests enhanced carbon assimilation and increased reproductive output in Brassica napus L.

    Science.gov (United States)

    Frenck, Georg; van der Linden, Leon; Mikkelsen, Teis Nørgaard; Brix, Hans; Jørgensen, Rikke Bagger

    2013-01-01

    Functional plant traits are likely to adapt under the sustained pressure imposed by environmental changes through natural selection. Employing Brassica napus as a model, a multi-generational study was performed to investigate the potential trajectories of selection at elevated [CO2] in two different temperature regimes. To reveal phenotypic divergence at the manipulated [CO2] and temperature conditions, a full-factorial natural selection regime was established in a phytotron environment over the range of four generations. It is demonstrated that a directional response to selection at elevated [CO2] led to higher quantities of reproductive output over the range of investigated generations independent of the applied temperature regime. The increase in seed yield caused an increase in aboveground biomass. This suggests quantitative changes in the functions of carbon sequestration of plants subjected to increased levels of CO2 over the generational range investigated. The results of this study suggest that phenotypic divergence of plants selected under elevated atmospheric CO2 concentration may drive the future functions of plant productivity to be different from projections that do not incorporate selection responses of plants. This study accentuates the importance of phenotypic responses across multiple generations in relation to our understanding of biogeochemical dynamics of future ecosystems. Furthermore, the positive selection response of reproductive output under increased [CO2] may ameliorate depressions in plant reproductive fitness caused by higher temperatures in situations where both factors co-occur. PMID:23762504

  10. Response to multi-generational selection under elevated [CO2] in two temperature regimes suggests enhanced carbon assimilation and increased reproductive output in Brassica napus L

    DEFF Research Database (Denmark)

    Frenck, Georg; van der Linden, Leon; Mikkelsen, Teis Nørgaard

    2013-01-01

    different temperature regimes. To reveal phenotypic divergence at the manipulated [CO2] and temperature conditions, a full-factorial natural selection regime was established in a phytotron environment over the range of four generations. It is demonstrated that a directional response to selection at elevated......Functional plant traits are likely to adapt under the sustained pressure imposed by environmental changes through natural selection. Employing Brassica napus as a model, a multi-generational study was performed to investigate the potential trajectories of selection at elevated [CO2] in two...... subjected to increased levels of CO2 over the generational range investigated. The results of this study suggest that phenotypic divergence of plants selected under elevated atmospheric CO2 concentration may drive the future functions of plant productivity to be different from projections that do...

  11. Influence of elevated temperature, pCO2, and nutrients on larva-biofilm interaction: Elucidation with acorn barnacle, Balanus amphitrite Darwin (Cirripedia: Thoracica)

    Science.gov (United States)

    Baragi, Lalita V.; Anil, Arga Chandrashekar

    2017-02-01

    Selection of optimal habitat by larvae of sessile organism is influenced by cues offered by the biofilm. Ocean warming and acidification are likely to enforce changes in the biofilm community and inturn influence the settlement process. Hence, we evaluated the influence of biofilm (multispecies and unialgal) and diet-mediated changes on the settlement of Balanus amphitrite cyprids (presettlement non-feeding larval stage) under different combinations of temperature (28, 30, 32 and 34 °C), pCO2 (400, 750 and 1500 μatm) and nutrient (unenriched and f/2 enriched). Nutrient enrichment enhanced the diatom and bacterial abundance at ambient temperature (30 °C) and pCO2 (400 μatm), which inturn increased larval settlement. Elevated pCO2 (750 and 1500 μatm) had no direct effect but a variable cascading effect on the settlement via biofilm-mediated changes was observed, depending on the type of biofilm. In contrast, elevated temperature (32 and 34 °C), either individually or in combination with elevated pCO2 had direct negative effect on settlement. However, biofilm-mediated changes compensated this negative effect. The larval settlement was also influenced by changes in the larval diet. Under elevated temperature and pCO2, cyprids raised with a feed (Chaetoceros calcitrans) from ambient temperature and pCO2 were of poor quality (lower RNA:DNA ratio, lower protein synthetic capacity) and yielded lower settlement. However, cyprids raised with a feed from elevated temperature and pCO2 were of better quality (higher RNA:DNA ratio, higher protein synthetic capacity) and yielded higher settlement. Overall, the observations from the present study provide insights into the significance of biotic interactions on the coastal biofouling communities under future climatic scenario and emphasise the need for future experiments on these aspects.

  12. The direct effects of increasing CO2 and temperature on non-calcifying organisms: increasing the potential for phase shifts in kelp forests.

    Science.gov (United States)

    Connell, Sean D; Russell, Bayden D

    2010-05-07

    Predictions about the ecological consequences of oceanic uptake of CO(2) have been preoccupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks the direct effects of CO(2) on non-calcareous taxa, particularly those that play critical roles in ecosystem shifts. We used two experiments to investigate whether increased CO(2) could exacerbate kelp loss by facilitating non-calcareous algae that, we hypothesized, (i) inhibit the recovery of kelp forests on an urbanized coast, and (ii) form more extensive covers and greater biomass under moderate future CO(2) and associated temperature increases. Our experimental removal of turfs from a phase-shifted system (i.e. kelp- to turf-dominated) revealed that the number of kelp recruits increased, thereby indicating that turfs can inhibit kelp recruitment. Future CO(2) and temperature interacted synergistically to have a positive effect on the abundance of algal turfs, whereby they had twice the biomass and occupied over four times more available space than under current conditions. We suggest that the current preoccupation with the negative effects of ocean acidification on marine calcifiers overlooks potentially profound effects of increasing CO(2) and temperature on non-calcifying organisms.

  13. Sick building syndrome in relation to air exchange rate, CO(2), room temperature and relative air humidity in university computer classrooms: an experimental study.

    Science.gov (United States)

    Norbäck, Dan; Nordström, Klas

    2008-10-01

    To study the effects of ventilation and temperature changes in computer classrooms on symptoms in students. Technical university students participated in a blinded study. Two classrooms had higher air exchange (4.1-5.2 ac/h); two others had lower (2.3-2.6 ac/h) air exchange. After 1 week, ventilation conditions were interchanged between the rooms. The students reported symptoms during the last hour, on a seven-step rating scale. Room temperature, relative air humidity (RH) carbon dioxide (CO(2)), PM10 and ultra-fine particles (UFP) were measured simultaneously (1 h). Illumination, air velocity, operative temperature, supply air temperature, formaldehyde, NO(2) and O(3) were measured. Multiple logistic regression was applied in cross-sectional analysis of the first answer (N = 355). Those participating twice (N = 121) were analysed longitudinally. Totally 31% were females, 2.9% smokers and 3.8% had asthma. Mean CO(2) was 993 ppm (674-1,450 ppm), temperature 22.7 degrees C (20-25 degrees C) and RH 24% (19-35%). Lower and higher air exchange rates corresponded to a personal outdoor airflow of 7 l/s*p and 10-13 L/s*P, respectively. Mean PM10 was 20 microg/m(3) at lower and 15 microg/m(3) at higher ventilation flow. Ocular, nasal and throat symptoms, breathlessness, headache and tiredness were significantly more common at higher CO(2) and temperature. After mutual adjustment, ocular (OR = 1.52 per 1 degrees C), nasal (OR = 1.62 per 1 degrees C) and throat symptoms (OR = 1.53 per 1 degrees C), headache (OR = 1.51 per 1 degrees C) and tiredness (OR = 1.54 per 1 degrees C) were significantly associated with temperature; headache was associated only with CO(2) (OR = 1.19 per 100 ppm CO(2)). Longitudinal analysis demonstrated that increased room temperature was related to tiredness (P < 0.05). Computer classrooms may have CO(2) above 1,000 ppm and temperatures above 22 degrees C. Increased temperature and CO(2) may affect mucosal membrane symptoms, headaches and tiredness

  14. Extraction and Separation of Volatile and Fixed Oils from Berries of Laurus nobilis L. by Supercritical CO2

    Directory of Open Access Journals (Sweden)

    M. Assunta Dessì

    2008-08-01

    Full Text Available Isolation of volatile and fixed oils from dried berries of Laurus nobilis L. from Tunisia have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at a temperature of 40 °C and pressures of 90 and 250 bar. The extraction step performed at 90 bar produced a volatile fraction mainly composed of (E-β-ocimene (20.9%, 1,8-cineole (8.8%, α-pinene (8.0%, β-longipinene (7.1%, linalool acetate (4.5%, cadinene (4.7%, β-pinene (4.2%, α-terpinyl acetate (3.8% and α-bulnesene (3.5%. The oil yield in this step of the process was 0.9 % by weight charged. The last extraction step at 250 bar produced an odorless liquid fraction, in which a very small percentage of fragrance compounds was found, whereas triacylglycerols were dominant. The yield of this step was 15.0 % by weight. The most represented fatty acids of the whole berry fixed oil were 12:0 (27.6%, 18:1 n-9 (27.1%, 18:2 n-6 (21.4%, and 16:0 (17,1%, with the 18:1 n-9 and 18:2 n-6 unsaturated fatty acids in particular averaging 329 μg/mg of oil.

  15. Antecedent moisture and temperature conditions modulate the response of ecosystem respiration to elevated CO2 and warming

    Science.gov (United States)

    Terrestrial plant and soil respiration, or ecosystem respiration (Reco), represents a major CO2 flux in the global carbon cycle. However, there is disagreement in how Reco will respond to future global changes, such as elevated atmosphere CO2 and warming. To address this, we synthesized six years (2...

  16. Arrangement of experiments for simulating the effects of elevated temperatures and elevated CO2 levels on field-sown crops in Finland

    Directory of Open Access Journals (Sweden)

    K. HAKALA

    2008-12-01

    Full Text Available The experimental plants: spring wheat, winter wheat, spring barley, meadow fescue, potato, strawberry and black currant were sown or planted directly in the field, part of which was covered by an automatically controlled greenhouse to elevate the temperature by 3°C. The temperature of the other part of the field (open field was not elevated, but the field was covered with the same plastic film as the greenhouse to achieve radiation and rainfall conditions comparable to those in the greenhouse. To elevate the CO2 concentrations, four open top chambers (OTC were built for the greenhouse, and four for the open field. Two of these, both in the greenhouse and in the open field, were supplied with pure CO2 to elevate their CO2 level to 700 ppm. The temperatures inside the greenhouse followed accurately the desired level. The relative humidity was somewhat higher in the greenhouse and in the OTC:s than in the open field, especially after the modifications in the ventilation of the greenhouse and in the OTC:s in 1994. Because the OTC:s were large (3 m in diameter, the temperatures inside them differed very little from the surrounding air temperature. The short-term variation in the CO2 concentrations in the OTC:s with elevated CO2 was, however, quite high. The control of the CO2 concentrations improved each year from 1992 to 1994, as the CO2 supplying system was modified. The effects of the experimental conditions on plant growth and phenology are discussed.;

  17. Investigating cluster formation in adsorption of CO2, CH4, and Ar in zeolites and metal organic frameworks at subcritical temperatures

    NARCIS (Netherlands)

    Krishna, R.; van Baten, J.M.

    2010-01-01

    The critical temperatures, T-c, of CO2, CH4, and Ar are 304 K, 191 K, and 151 K, respectively. This paper highlights some unusual characteristics of adsorption and diffusion of these molecules in microporous structures such as zeolites and metal organic frameworks at temperatures T < T-c. Published

  18. 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.

  19. CO2Removal from Biogas by Cyanobacterium Leptolyngbya sp. CChF1 Isolated from the Lake Chapala, Mexico: Optimization of the Temperature and Light Intensity.

    Science.gov (United States)

    Choix, Francisco J; Snell-Castro, Raúl; Arreola-Vargas, Jorge; Carbajal-López, Alberto; Méndez-Acosta, Hugo O

    2017-12-01

    In the present study, the capacity of the cyanobacterium Leptolyngbya sp. CChF1 to remove CO 2 from real and synthetic biogas was evaluated. The identification of the cyanobacterium, isolated from the lake Chapala, was carried out by means of morphological and molecular analyses, while its potential for CO 2 removal from biogas streams was evaluated by kinetic experiments and optimized by a central composite design coupled to a response surface methodology. Results demonstrated that Leptolyngbya sp. CChF1 is able to remove CO 2 and grow indistinctly in real or synthetic biogas streams, showing tolerance to high concentrations of CO 2 and CH 4 , 25 and 75%, respectively. The characterization of the biomass composition at the end of the kinetic assays revealed that the main accumulated by-products under both biogas streams were lipids, followed by proteins and carbohydrates. Regarding the optimization experiments, light intensity and temperature were the studied variables, while synthetic biogas was the carbon source. Results showed that light intensity was significant for CO 2 capture efficiency (p = 0.0290), while temperature was significant for biomass production (p = 0.0024). The predicted CO 2 capture efficiency under optimal conditions (27.1 °C and 920 lx) was 93.48%. Overall, the results of the present study suggest that Leptolyngbya sp. CChF1 is a suitable candidate for biogas upgrading.

  20. Simple synthesis of porous melamine-formaldehyde resins by low temperature solvothermal method and its CO2 adsorption properties

    Directory of Open Access Journals (Sweden)

    F. Yin

    2017-11-01

    Full Text Available A simple and environmentally-friendly approach for the preparation of porous melamine-formaldehyde resins (PMFRs was developed by using low-boiling-point solvents, such as water, as pore-forming agent. With using dimethyl sulfoxide (DMSO and low-boiling solvents cosolvent method, PMFRs with a high specific surface area and well-defined pore structure can be synthesized at a low reaction temperature of 140 °C for a short reaction duration in 20 hours, which can replace the conventional methods that use dimethyl sulfoxide (DMSO as reaction medium and require 3 days at 170 °C to achieve similar surface area. When loaded with polyethylenimine (PEI, the PMFR-PEI-30% showed good CO2 adsorption performance with a capacity of up to 2.89 mmol/g at 30 °C. These results bring new perspectives for the development of lowcost and environmentally-friendly synthetic methods for porous materials, which can boost their widespread applications.

  1. Gas liquid equilibrium prediction of system (CO2-aqueous ethanol at moderate pressure and different temperatures using PR-EOS

    Directory of Open Access Journals (Sweden)

    Hadi Jasim Arkan

    2013-01-01

    Full Text Available One of the most important design considerations which should not be ignored during the equipment designing for some industrial purpose is vapour-liquid equilibrium (VLE. Thus, in chemical engineering, the first step is the computation of VLE properties of materials by employing Equation of state (EOS. In this study, we have used a thermodynamic model which was established for binary system of carbon dioxide (1-(2 solubility of CO2 in aqueous ethanol and it was employed to estimate the gas-liquid equilibrium at moderate pressures (till 6 bar and varying temperatures (288 K to 323 K. Peng-Robinson EOS was employed to determine the VLE properties. Mixing rules such as vanderWaals and quadratic mixing rules were also used for the determination of ethanol-water mixture critical parameters which entails the pseudo-critical method as one component and results obtained from this study were similar to the ones reported in recent literature for empirical phase equilibrium studies.

  2. Physiographic position modulates the influence of temperature and precipitation as controls over leaf and ecosystem level CO2 flux in shrubland ecosystems

    Science.gov (United States)

    Barron-Gafford, G. A.; Scott, R. L.; Jenerette, G. D.; Hamerlynck, E. P.; Huxman, T. E.

    2010-12-01

    Conversion of semiarid grasslands to shrublands may alter the sensitivity of CO2 exchange of both the dominant plants and the entire ecosystem to variation in air temperature and precipitation. We used a combination of leaf-level gas exchange experimentation and ecosystem-level eddy covariance monitoring techniques to quantify the temperature sensitivity of a riparian and upland shrubland across seasonal periods of differing precipitation input in southeastern Arizona, USA. Maximum rates of net CO2 uptake were estimated from a Lorentzian peak function fitted to net uptake plotted against air temperature, with optimum temperature being that at which maximum uptake occurred. The convexity of the temperature response function was quantified by the range of temperatures over which a leaf or an ecosystem assimilated 50% and 75% of maximum net CO2 uptake. We quantified the temperature response of both the dominant vegetative components within both semiarid shrublands of differing physiographic position and the ecosystems themselves to examine how temperature sensitivity varies with access to stable groundwater. By repeatedly measuring CO2 uptake across a wide range of temperatures and estimating soil respiration, we quantified the temperature sensitivity of these systems, computed changes in those responses due to periods of precipitation input, and estimated the role of component fluxes in driving ecosystem-scale responses. We found that having a connectivity to stable groundwater sources decoupled leaf-and ecosystem-scale temperature sensitivity relative to comparable sites lacking such access. Access to groundwater not only resulted in the temperature sensitivity of the riparian shrubland being nearly half that of the upland throughout all seasonal periods, but also actual rates of net ecosystem productivity (NEP) being 1.5X greater when precipitation was relatively abundant and five times greater when it was not. Maxima rates of NEP were nine times more responsive to

  3. Effect of pristine and functionalized single- and multi-walled carbon nanotubes on CO2separation of mixed matrix membranes based on polymers of intrinsic microporosity (PIM-1): a molecular dynamics simulation study.

    Science.gov (United States)

    Golzar, Karim; Modarress, Hamid; Amjad-Iranagh, Sepideh

    2017-08-19

    Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations were conducted to investigate the transport properties of carbon dioxide, methane, nitrogen, and oxygen through pure and mixed matrix membranes (MMMs) based on polymers of intrinsic microporosity (PIM-1). For this purpose, first, 0.5 to 3 wt% of pristine single-walled carbon nanotube (p-SWCNT) and multi-walled carbon nanotube (p-MWCNT) were embedded into the pure PIM-1, and then for better dispersion of CNT particles into the polymer matrix and to improve the performance of the resulting MMMs, polyethylene glycol (PEG) functionalized SWCNT and MWCNT (f-SWCNT and f-MWCNT, respectively) were loaded. The characterization of the obtained MMMs was carried out by using density, glass transition temperature, X-ray pattern, and fractional free volume calculations. Comparing the obtained results with the available reported experimental data, indicate the authenticity of the applied simulation approach. The simulation results exhibit that the pristine and PEG-functionalized CNT particles improve the transport properties such as diffusivity, solubility, and permeability of the PIM-1 membranes, without sacrificing their selectivity. Also, the MMMs incorporated with 2 wt% of the functionalized CNT particles indicate better performance for the CO 2 separation from other gases. According to the calculated results, the highest permeability and diffusivity for CO 2 are observed in the [PIM-1/f-SWCNT] MMM among the other membranes which represent that the loading of the f-SWCNTs can enhance the CO 2 separation performance of PIM-1 more than other CNTs studied in this work.

  4. Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root / shoot herbivores

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2013-11-01

    Full Text Available Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT and elevated atmospheric carbon dioxide (eCO2 are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus and colonisation by the pea aphid (Acyrthosiphon pisum, on three cultivars of a common host plant, lucerne (Medicago sativa. Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 on three trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing, with cultivar ‘Sequel’ achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonisation was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonisation rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

  5. Devices and methods to measure H2 and CO2 concentrations in gases released from soils and low temperature fumaroles in volcanic areas

    Science.gov (United States)

    di Martino, R. M. R.; Camarda, M.; Gurrieri, S.; Valenza, M.

    2009-04-01

    response time, and linearity of signal. We determine the CO2 concentration in the gas mixture with an I.R. spectrometer that has a measuring range of 0-100% with accuracy of ± 2% of the range and response time of 10 seconds. The laboratory results confirm our hypothesis of interference between H2, H2S and CO in the full concentration range of contaminant species. Therefore, according to our studies, the assignment of the fuel cell signal output variations only to H2 variation of concentration as in past studies, without physical separation of different reducing species may be misleading. Continuous measurements and periodical measurement field trip were performed at Torre Del Filosofo site on the upper part of the Etna volcano from the end of July to the middle October 2008. In field applications, H2S was removed with a Pb(COOH)2 trap whereas CO interference was neglected because H2/CO ratios in volcanic gases are typically high. Field time-series measurements of H2 and CO2 in gases emitted by low temperature fumaroles at Torre del Filosofo site showed a close positive correlation between explosion activity and the major peaks in the hydrogen concentration.

  6. Cooling-induced shape memory effect and inverse temperature dependence of superelastic stress in Co2Cr(Ga,Si) ferromagnetic Heusler alloys

    Science.gov (United States)

    Xu, Xiao; Omori, Toshihiro; Nagasako, Makoto; Okubo, Akinari; Umetsu, Rie Y.; Kanomata, Takeshi; Ishida, Kiyohito; Kainuma, Ryosuke

    2013-10-01

    Normally, shape memory effect (SME) is obtained by the reverse martensitic transformation, therefore only induced by heating a sample from the deformed martensite phase. In this study, we report a phenomenon of cooling-induced SME, observed in a Co2Cr(Ga,Si) Heusler alloy, where the normal heating-induced SME can be obtained at the same time. The cooling-induced SME is attributed to an abnormal martensitic transformation in Co2Cr(Ga,Si) Heusler alloy. Moreover, an inverse temperature dependence of superelastic stress was also observed. The discoveries of these phenomena provide application possibilities for shape memory alloys, especially at low temperatures.

  7. Increased [CO2] does not compensate for negative effects on yield caused by higher temperature and [O3] in Brassica napus L

    DEFF Research Database (Denmark)

    Frenck, Georg; van der Linden, Leon Gareth; Mikkelsen, Teis Nørgaard

    2011-01-01

    in existing genotypes is vital. In this study, the responses in yield and biomass production of four different cultivars of oilseed rape (Brassica napus L.) were tested under five different combinations of increased [CO2] (700 ppm), temperature (+5 °C) and [O3] (+40 ppb). Especially the multifactor treatments....... Our results suggest that future breeding of B. napus should be based on old cultivars, since more modern varieties seem to have lower potentials to respond to CO2 and thus counteract the detrimental effects of yield reducing environmental factors such as temperature and O3....

  8. Concurrent elevation of CO2, O3 and temperature severely affects oil quality and quantity in rapeseed

    DEFF Research Database (Denmark)

    Namazkar, Shahla; Stockmarr, Anders; Frenck, Georg

    2016-01-01

    Plant oil is an essential dietary and bio-energy resource. Despite this, the effects of climate change on plant oil quality remain to be elucidated. The present study is the first to show changes in oil quality and quantity of four rapeseed cultivars in climate scenarios with elevated [CO2], [O3...... FAs remained unchanged or even increased. Most reduced was the FA essential for human nutrition, C18:3-ω3, which decreased by 39% and 45% in the combined scenarios with elevated [CO2]+T+[O3] and [CO2]+T, respectively. Average oil content decreased 3–17%. When [CO2] and T were elevated concurrently......, the seed biomass was reduced by half, doubling the losses in FAs and oil content. This corresponded to a 58% reduction in the oil yield per hectare, and C18:3-ω3 decreased by 77%. Furthermore, the polyunsaturated FAs were significantly decreased. The results indicate undesirable consequences for production...

  9. Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil.

    Science.gov (United States)

    Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

    2016-09-29

    Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

  10. Industrial-age changes in atmospheric [CO2] and temperature differentially alter responses of faster- and slower-growing Eucalyptus seedlings to short-term drought.

    Science.gov (United States)

    Lewis, James D; Smith, Renee A; Ghannoum, Oula; Logan, Barry A; Phillips, Nathan G; Tissue, David T

    2013-05-01

    Climate change may alter forest composition by differentially affecting the responses of faster- and slower-growing tree species to drought. However, the combined effects of rising atmospheric CO2 concentration ([CO2]) and temperature on drought responses of trees are poorly understood. Here, we examined interactive effects of temperature (ambient, ambient + °C) and [CO2] (290, 400 and 650mu;l l(-1)) on drought responses of Eucalyptus saligna Sm. (faster-growing) and E. sideroxylon A. Cunn. ex Woolls (slower-growing) seedlings. Drought was imposed via a controlled reduction in soil water over 1-2 weeks, re-watering seedlings when leaves visibly wilted. In ambient temperature, the effect of drought on the light-saturated net photosynthetic rate (Asat) in E. saligna decreased as [CO2] increased from pre-industrial to future concentrations, but rising [CO2] did not affect the response in Eucalyptus sideroxylon. In contrast, elevated temperature exacerbated the effect of drought in reducing Asat in both species. The drought response of Asat reflected changes in stomatal conductance (gs) associated with species and treatment differences in (i) utilization of soil moisture and (ii) leaf area ratio (leaf area per unit plant dry mass). Across [CO2] and temperature treatments, E. saligna wilted at higher soil water potentials compared with E. sideroxylon. Photosynthetic recovery from drought was 90% complete 2 days following re-watering across all species and treatments. Our results suggest that E. saligna (faster-growing) seedlings are more susceptible to drought than E. sideroxylon (slower-growing) seedlings. The greater susceptibility to drought of E. saligna reflected faster drawdown of soil moisture, associated with more leaf area and leaf area ratio, and the ability of E. sideroxylon to maintain higher gs at a given soil moisture. Inclusion of a pre-industrial [CO2] treatment allowed us to conclude that susceptibility of these species to short-term drought

  11. Seasonality in a boreal forest ecosystem affects the use of soil temperature and moisture as predictors of soil CO2 efflux

    Directory of Open Access Journals (Sweden)

    S. Kellomäki

    2011-11-01

    Full Text Available Our objectives were to identify factors related to temporal variation of soil CO2 efflux in a boreal pine forest and to evaluate simple predictive models of temporal variation of soil CO2 efflux. Soil CO2 efflux was measured with a portable chamber in a Finnish Scots pine forest for three years, with a fourth year for model evaluation. Plot averages for soil CO2 efflux ranged from 0.04 to 0.90 g CO2 m−2 h−1 during the snow-free period, i.e. May–October, and from 0.04 to 0.13 g CO2 m−2 h−1 in winter. Soil temperature was a good predictor of soil CO2 efflux. A quadratic model of ln-transformed efflux explained 76–82 % of the variation over the snow-free period. The results revealed an effect of season: at a given temperature of the organic layer, soil CO2 efflux was higher later in the snow-free period (in August and September than in spring and early summer (in May and June. Regression coefficients for temperature (approximations of a Q10 value of month-specific models decreased with increasing average soil temperatures. Efflux in July, the month of peak photosynthesis, showed no clear response to temperature or moisture. Inclusion of a seasonality index, degree days, improved the accuracy of temperature response models to predict efflux for the fourth year of measurements, which was not used in building of regression models. During peak efflux from mid-July to late-August, efflux was underestimated with the models that included degree days as well as with the models that did not. The strong influence of the flux of photosynthates belowground and the importance of root respiration could explain the relative temperature insensitivity observed in July and together with seasonality of growth of root and root-associated mycorrhizal fungi could explain partial failure of models to predict magnitude of efflux in the peak season from mid-July to August. The effect of moisture early in the season was confounded by simultaneous advancement of

  12. 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.

  13. Synthesis and development of ordered, phase-separated, room-temperature ionic liquid-based AB and ABC block copolymers for gas separation applications

    Science.gov (United States)

    Wiesenauer, Erin F.

    CO2 capture process development is an economically and environmentally important challenge, as concerns over greenhouse gas emissions continue to receive worldwide attention. Many applications require the separation of CO 2 from other light gases such as N2, CH4, and H2 and a number of technologies have been developed to perform such separations. While current membrane technology offers an economical, easy to operate and scale-up solution, polymeric membranes cannot withstand high temperatures and aggressive chemical environments, and they often exhibit an unfavorable tradeoff between permeability and selectivity. Room-temperature ionic-liquids (RTILs) are very attractive as next-generation CO2-selective separation media and their development into polymerized membranes combat these challenges. Furthermore, polymers that can self-assemble into nanostructured, phase-separated morphologies (e.g., block copolymers, BCPs) have a direct effect on gas transport as materials morphology can influence molecular diffusion and membrane transport performance. In this thesis, nanophase-separated, RTIL-based AB and ABC di- and tri-BCPs were prepared via the sequential, living ring-opening metathesis polymerization (ROMP) of an IL-based monomer and one or more mutually immiscible co-monomers. This novel type of ion-containing BCP system forms various ordered nanostructures in the melt state via primary and secondary structure control. Monomer design and control of block composition, sequence, and overall polymer lengths were found to directly affect the ordered polymer assembly. Supported, composite membranes of these new BCPs were successfully fabricated, and the effect of BCP composition and nanostructure on CO2/light gas transport properties was studied. These nanostructured IL-based BCPs represent innovative polymer architectures and show great potential CO2/light gas membrane separation applications.

  14. Micro-scale thermal imaging of CO2 absorption in the thermochemical energy storage of Li metal oxides at high temperature

    Science.gov (United States)

    Morikawa, Junko; Takasu, Hiroki; Zamengo, Massimiliano; Kato, Yukitaka

    2017-05-01

    Li-Metal oxides (typical example: lithium ortho-silicate Li4SiO4) are regarded as a novel solid carbon dioxide CO2 absorbent accompanied by an exothermic reaction. At temperatures above 700°C the sorbent is regenerated with the release of the captured CO2 in an endothermic reaction. As the reaction equilibrium of this reversible chemical reaction is controllable only by the partial pressure of CO2, the system is regarded as a potential candidate for chemical heat storage at high temperatures. In this study, we applied our recent developed mobile type instrumentation of micro-scale infrared thermal imaging system to observe the heat of chemical reaction of Li4SiO4 and CO2 at temperature higher than 600°C or higher. In order to quantify the micro-scale heat transfer and heat exchange in the chemical reaction, the superimpose signal processing system is setup to determine the precise temperature. Under an ambient flow of carbon dioxide, a powder of Li4SiO4 with a diameter 50 micron started to shine caused by an exothermic chemical reaction heat above 600°C. The phenomena was accelerated with increasing temperature up to 700°C. At the same time, the reaction product lithium carbonate (Li2CO3) started to melt with endothermic phase change above 700°C, and these thermal behaviors were captured by the method of thermal imaging. The direct measurement of multiple thermal phenomena at high temperatures is significant to promote an efficient design of chemical heat storage materials. This is the first observation of the exothermic heat of the reaction of Li4SiO4 and CO2 at around 700°C by the thermal imaging method.

  15. Kinetic study of low-temperature CO2 plasmas under non-equilibrium conditions. I. Relaxation of vibrational energy

    Science.gov (United States)

    Silva, T.; Grofulović, M.; Klarenaar, B. L. M.; Morillo-Candas, A. S.; Guaitella, O.; Engeln, R.; Pintassilgo, C. D.; Guerra, V.

    2018-01-01

    A kinetic model describing the time evolution of ∼70 individual CO2(X1Σ+) vibrational levels during the afterglow of a pulsed DC glow discharge is developed in order to contribute to the understanding of vibrational energy transfer in CO2 plasmas. The results of the simulations are compared against in situ Fourier transform infrared spectroscopy data obtained in a pulsed DC glow discharge and its afterglow at pressures of a few Torr and discharge currents of around 50 mA. The very good agreement between the model predictions and the experimental results validates the kinetic scheme considered here and the corresponding vibration–vibration and vibration–translation rate coefficients. In this sense, it establishes a reaction mechanism for the vibrational kinetics of these CO2 energy levels and offers a firm basis to understand the vibrational relaxation in CO2 plasmas. It is shown that first-order perturbation theories, namely, the Schwartz–Slawsky–Herzfeld and Sharma–Brau methods, provide a good description of CO2 vibrations under low excitation regimes.

  16. Elevated CO2, warmer temperatures and soil water deficit affect plant growth, physiology and water use of cotton (Gossypium hirsutum L.)

    Science.gov (United States)

    Changes in temperature, atmospheric [CO2] and precipitation under the scenarios of projected climate change present a challenge to crop production, and may have significant impacts on the physiology, growth and yield of cotton (Gossypium hirsutum L.). A glasshouse experiment explored the early growt...

  17. ELEVATED CO2 AND ELEVATED TEMPERATURE HAVE NO EFFECT ON DOUGLAS-FIR FINE-ROOT DYNAMICS IN NITROGEN-POOR SOIL

    Science.gov (United States)

    Here, we investigate fine-root production, mortality and standing crop of Douglas-fir (Pseudotsuga menziesii) seedlings exposed to elevated atmospheric CO2 and elevated air temperature. We hypothesized that these treatments would increase fine-root production, but that mortality ...

  18. Investigation on temperature separation and flow behaviour in vortex chamber

    Science.gov (United States)

    Matsuno, Yuhi; Fukushima, Yusuke; Matsuo, Shigeru; Hashimoto, Tokitada; Setoguchi, Toshiaki; Kim, Heuy Dong

    2015-04-01

    In the previous researches, it is known that the swirl flow in circular pipe causes the temperature separation. Recently, it is shown that the temperature separation occurs in a vortex chamber when compressed air are pumped into this device from the periphery. Especially, in a cavity installed in the periphery of the chamber, the highest temperature was observed. Therefore, it is expected that this device can be used as a heat source in the engineering field. In recent researches, the mechanism of temperature separation in vortex chamber has been investigated by some researchers. However, there are few researches for the effect of diameter and volume of vortex chamber, height of central rod and position of cavity on the temperature separation. Further, no detailed physical explanation has been made for the temperature separation phenomena in the vortex chamber. In the present study, the effects of chamber configuration and position of the cavity on temperature separation in the vortex chamber were investigated experimentally.

  19. A flow-through, elevated-temperature and -pressure NMR apparatus for in-situ CO2 sequestration studies.

    Science.gov (United States)

    Sesti, Erika L; Cui, Jinlei; Hayes, Sophia E; Conradi, Mark S

    2017-09-01

    We report an apparatus for in-situ nuclear magnetic resonance (NMR) studies of chemical reactions of dissolved 13CO2 with minerals (rock or powder) under continuous flow. The operating range of the apparatus is 18-150°C and 1-140bar. A flow pump is used to circulate a CO2-water solution, with a heated mixing vessel where CO2 gas equilibrates with a water solution. The NMR probe is built around a strong zirconia ceramic vessel, with o-ring sealed connections; the mineral is contained inside. The horizontal orientation of the zirconia vessels allows use of a radio frequency (rf) solenoid for improved spin sensitivity. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Drought increases heat tolerance of leaf respiration in Eucalyptus globulus saplings grown under both ambient and elevated atmospheric [CO2] and temperature

    Science.gov (United States)

    Gauthier, Paul P. G.; Crous, Kristine Y.; Ayub, Gohar; Duan, Honglang; Weerasinghe, Lasantha K.; Ellsworth, David S.; Tjoelker, Mark G.; Evans, John R.; Tissue, David T.; Atkin, Owen K.

    2014-01-01

    Climate change is resulting in increasing atmospheric [CO2], rising growth temperature (T), and greater frequency/severity of drought, with each factor having the potential to alter the respiratory metabolism of leaves. Here, the effects of elevated atmospheric [CO2], sustained warming, and drought on leaf dark respiration (R dark), and the short-term T response of R dark were examined in Eucalyptus globulus. Comparisons were made using seedlings grown under different [CO2], T, and drought treatments. Using high resolution T–response curves of R dark measured over the 15–65 °C range, it was found that elevated [CO2], elevated growth T, and drought had little effect on rates of R dark measured at T drought on T response of R dark. However, drought increased R dark at high leaf T typical of heatwave events (35–45 °C), and increased the measuring T at which maximal rates of R dark occurred (T max) by 8 °C (from 52 °C in well-watered plants to 60 °C in drought-treated plants). Leaf starch and soluble sugars decreased under drought and elevated growth T, respectively, but no effect was found under elevated [CO2]. Elevated [CO2] increased the Q 10 of R dark (i.e. proportional rise in R dark per 10 °C) over the 15–35 °C range, while drought increased Q 10 values between 35 °C and 45 °C. Collectively, the study highlights the dynamic nature of the T dependence of R dark in plants experiencing future climate change scenarios, particularly with respect to drought and elevated [CO2]. PMID:25205579

  1. Study of pressure broadening effects of H2 on CO2 and CO in the near infrared region between 6317 and 6335 cm-1 at room temperature

    Science.gov (United States)

    Padmanabhan, A.; Tzanetakis, T.; Chanda, A.; Thomson, M. J.

    2014-01-01

    In this absorption spectroscopy study of CO2 and CO in the near-infrared (NIR) region between 6317 and 6335 cm-1, we focus on the broadening effect of H2 at room temperature (296 K). Absorption spectra were collected using a Tunable Diode Laser (TDL) operating in the NIR for various gas mixtures filled in a monel gas cell. The experimental parameters chosen in this study are highly relevant to combustion-related industrial applications where TDL sensors are employed to monitor CO2 and CO emissions. In many such applications H2 is always present and there is a need to understand the broadening effect of H2 on CO2 and CO to improve the detection quality of such sensors. Voigt profile analysis was performed to retrieve the experimental parameters. CO2-H2 broadening coefficients are presented for room temperature. From our study on the CO-H2 broadening effect at room temperature, we conclude that within the sensitivity of the measurements made, the presence of H2 has no significant effect in this region. The parameters calculated in this study are intended to be an addition to spectroscopic databases such as HITRAN.

  2. Arbuscular Mycorrhizal Fungi May Mitigate the Influence of a Joint Rise of Temperature and Atmospheric CO2 on Soil Respiration in Grasslands

    Directory of Open Access Journals (Sweden)

    S. Vicca

    2009-01-01

    Full Text Available We investigated the effects of mycorrhizal colonization and future climate on roots and soil respiration (Rsoil in model grassland ecosystems. We exposed artificial grassland communities on pasteurized soil (no living arbuscular mycorrhizal fungi (AMF present and on pasteurized soil subsequently inoculated with AMF to ambient conditions and to a combination of elevated CO2 and temperature (future climate scenario. After one growing season, the inoculated soil revealed a positive climate effect on AMF root colonization and this elicited a significant AMF x climate scenario interaction on root biomass. Whereas the future climate scenario tended to increase root biomass in the noninoculated soil, the inoculated soil revealed a 30% reduction of root biomass under warming at elevated CO2 (albeit not significant. This resulted in a diminished response of Rsoil to simulated climatic change, suggesting that AMF may contribute to an attenuated stimulation of Rsoil in a warmer, high CO2 world.

  3. 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.

  4. The temperature response of CO2 assimilation, photochemical activities and Rubisco activation in Camelina sativa, a potential bioenergy crop with limited capacity for acclimation to heat stress.

    Science.gov (United States)

    Carmo-Silva, A Elizabete; Salvucci, Michael E

    2012-11-01

    The temperature optimum of photosynthesis coincides with the average daytime temperature in a species' native environment. Moderate heat stress occurs when temperatures exceed the optimum, inhibiting photosynthesis and decreasing productivity. In the present study, the temperature response of photosynthesis and the potential for heat acclimation was evaluated for Camelina sativa, a bioenergy crop. The temperature optimum of net CO(2) assimilation rate (A) under atmospheric conditions was 30-32 °C and was only slightly higher under non-photorespiratory conditions. The activation state of Rubisco was closely correlated with A at supra-optimal temperatures, exhibiting a parallel decrease with increasing leaf temperature. At both control and elevated temperatures, the modeled response of A to intercellular CO(2) concentration was consistent with Rubisco limiting A at ambient CO(2). Rubisco activation and photochemical activities were affected by moderate heat stress at lower temperatures in camelina than in the warm-adapted species cotton and tobacco. Growth under conditions that imposed a daily interval of moderate heat stress caused a 63 % reduction in camelina seed yield. Levels of cpn60 protein were elevated under the higher growth temperature, but acclimation of photosynthesis was minimal. Inactivation of Rubisco in camelina at temperatures above 35 °C was consistent with the temperature response of Rubisco activase activity and indicated that Rubisco activase was a prime target of inhibition by moderate heat stress in camelina. That photosynthesis exhibited no acclimation to moderate heat stress will likely impact the development of camelina and other cool season Brassicaceae as sources of bioenergy in a warmer world.

  5. Long-term variability of iron supply, marine export production, and sea surface temperature in the subantarctic Atlantic, implications for atmospheric CO2

    Science.gov (United States)

    Martinez-Garcia, A.; Rosell-Mele, A.; Geibert, W.; Gersonde, R.; Masque, P.; Gaspari, V.; Barbante, C.

    2008-12-01

    Paleoclimatic reconstructions have provided a unique dataset to test the sensitivity of climate system to changes in atmospheric CO2 concentrations. However, the mechanisms behind glacial/interglacial (G/IG) variations in atmospheric CO2 concentrations observed in the Antarctic ice cores over the last 800 ky are still not completely understood. Here we present a multiproxy dataset of sea surface temperatures (SST), dust and iron supply, and marine export production, from the marine sediment core PS2489-2/ODP Site 1090 located in the subantarctic Atlantic (SA). This dataset allows us to evaluate various hypotheses focussing on the role of the Southern Ocean (SO) in modulating atmospheric CO2 over the last 800ky, and provides new information on SST, dust, and export production back to the Pliocene. The close correlation observed between iron inputs and marine export production in our record suggests that the process of iron fertilization has been a recurrent process operating in the SA over the G/IG cycles of the last 1.1 My. However, our data indicates that marine productivity in the present Subantarctic Zone can only explain a fraction of atmospheric CO2 changes occurring at glacial maxima in each glacial stage. Moreover, the good correlation of our SST to the EPICA Dome C records (EDC) temperature reconstruction over the last 800ka, suggest that physical processes, possibly related to changes in Antarctic sea-ice extent, surface water stratification and westerly winds position have also played an important role in modulating atmospheric CO2 over the last 800ky. On the long-term, our paleo-SST record reveals a major cooling event around 1.2-1.5 Ma that may have caused a profound impact on atmospheric CO2 and hence in the transition to a 100 kyr world during the Middle Pleistocene Climatic Transition.

  6. Are microbial N transformation rates in a permanent grassland soil after 17 years of elevated atmospheric CO2 sensitive to soil temperature?

    Science.gov (United States)

    Moser, Gerald; Gorenflo, André; Brenzinger, Kristof; Clough, Tim; Braker, Gesche; Müller, Christoph

    2016-04-01

    Long-term observations (17 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed that the carbon fertilization caused significant changes in the ecosystem nitrogen cycle. These changes are responsible for a doubling of annual N2O emissions under elevated atmospheric CO2 (eCO2) caused by increased emissions during the plant growing season. The goal of this lab study was to understand how soil temperature influences the long-term effects of eCO2 and plant carbon input on microbial N transformations in the Giessen FACE. Therefore, a pulse labelling study with 15N tracing of 15NH4+ and 15NO3- was carried out with incubated soil samples from elevated and ambient CO2 FACE rings in climate chambers at two different temperatures (10°C and 19°C), while water filled pore space of the samples was adjusted to the same level. The various N pools in the soil (NH4+, NO3-, NO2-, soil organic matter), N2O emissions and simultaneous gross N transformation rates were quantified. The quantification of the gross N transformations are based on the turnover of 15NH4+, 15NO3-, 15NO2- and shall illuminate the interaction between carbon fertilization, temperature and changes in nitrogen cycle in this grassland soil. While the soil respiration after labelling was significantly increased at 19°C compared to 10°C, N2O emissions showed no significant differences. There were also no significant differences of N2O emissions between soil samples from control and elevated CO2 rings within each temperature level. As the soil temperature (within the range of 10-19°C) had no significant effects on N transformations responsible for the observed doubling of N2O emissions under eCO2, it seems most likely that other factors like direct carbon input by plants and/or soil moisture differences between ambient and elevated rings in the field are responsible for the observed increase in N2O emissions under eCO2.

  7. Five-years of microenvironment data along an urban-rural transect; temperature and CO2 concentrations in urban area at levels expected globally with climate change.

    Energy Technology Data Exchange (ETDEWEB)

    George, Kate; Ziska, Lewis H; Bunce, James A; Quebedeaux, Bruno

    2007-11-01

    The heat island effect and the high use of fossil fuels in large city centers is well documented, but by how much fossil fuel consumption is elevating atmospheric CO2 concentrations and whether elevations in both atmospheric CO2 and air temperature are consistent from year to year are less well known. Our aim was to record atmospheric CO2 concentrations, air temperature and other environmental variables in an urban area and compare it to suburban and rural sites to see if urban sites are experiencing climates expected globally in the future with climate change. A transect was established from Baltimore city center (Urban site), to the outer suburbs of Baltimore (suburban site) and out to an organic farm (rural site). At each site a weather station was set-up to monitor environmental variables annually for five years. Atmospheric CO2 was significantly increased on average by 66 ppm from the rural to the urban site over the five years of the study. Air temperature was significantly higher at the urban site (14.8 oC) compared to the suburban (13.6 oC) and rural (12.7 oC) sites. Relative humidity was not different between sites but vapor pressure deficit (VPD) was significantly higher at the urban site compared to the suburban and rural sites. During wet years relative humidity was significantly increased and VPD significantly reduced. Increased nitrogen deposition at the rural site (2.1 % compared to 1.8 and 1.2 % at the suburban and urban sites) was small enough not to affect soil nitrogen content. Dense urban areas with large populations and high vehicular traffic have significantly different microclimates compared to outlying suburban and rural areas. The increases in atmospheric CO2 and air temperature are similar to changes predicted in the short term with global climate change, therefore providing an environment suitable for studying future effects of climate change on terrestrial ecosystems.

  8. Effect of monomer mixture composition on structure and chromatographic properties of poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monolithic rod columns for separation of small molecules.

    Science.gov (United States)

    Smirnov, Konstantin N; Dyatchkov, Ivan A; Telnov, Maxim V; Pirogov, Andrey V; Shpigun, Oleg A

    2011-07-29

    Porous poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monoliths were synthesized via thermally initiated free-radical polymerization in confines of surface-vinylized glass columns (150 mm × 3 mm i.d.) and applied to the reversed-phase separation of low-molecular-weight aromatic compounds. In order to compensate for the polymer shrinkage during the synthesis and prevent the monolith from detachment from the column wall, polymerization was conducted under nitrogen pressure. The reaction proceeded at 60°C for 22 h. 2,2'-Azo-bis-isobutironitrile was used as the initiator and 1-dodecanol was used as the porogen. A series of monoliths with different monomer ratios were obtained. All the monoliths had high specific surface areas ranging from 370 to 490 m(2)/g. In the studied range of monomer mixture compositions, the mechanical stability of the stationary phase in water/acetonitrile eluents was found to be high enough and practically insensitive to the fraction of 2-hydroxyethyl methacrylate (HEMA). Increasing the molar fraction of HEMA from 10.5% to 14.7% resulted in the decrease of column permeability by two orders of magnitude (from 1.1×10(-12) to 1.8×10(-14) m(2)) and led to weaker retention of alkylbenzenes. The higher HEMA content was shown to reduce the plate height of the columns in the separation of small molecules from 160-490 μm to 40-76 μm. This was attributed mainly to the decrease of the domain size of the monoliths leading to lower eddy dispersion and mass transfer resistance in the column. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. In-line formation of chemically cross-linked P84® co-polyimide hollow fibre membranes for H2/CO2 separation

    KAUST Repository

    Choi, Seung Hak

    2010-12-13

    In this study, chemically cross-linked asymmetric P84® co-polyimide hollow fibre membranes with enhanced separation performance were fabricated, using a dry-wet spinning process with an innovative in-line cross-linking step. The chemical modification was conducted by controlled immersion of the coagulated fibre in an aqueous 1,5-diamino-2-methylpentane (DAMP) cross-linker solution before the take-up. The effect of the cross-linker concentration on the thermal, mechanical, chemical and gas transport properties of the membranes was investigated. FT-IR/ATR analysis was used to identify the chemical changes in the polymer, while DSC analysis confirmed the changes in the Tg and the specific heat of the polymer upon cross-linking. Chemical cross-linking with a 10 wt.% aqueous DAMP solution strongly enhanced the H2/CO2 ideal selectivity from 5.3 to 16.1, while the H2 permeance of the membranes decreased from 7.06 × 10−3 to 1.01 × 10−3 m3(STP) m−2 h−1 bar−1 for a feed pressure of 1 bar at 25 °C. The increase of selectivity with decreasing permeance is somewhat higher than the slope in the Robeson upper bound, evidencing the positive effect of the cross-linking on the separation performance of the fibres. Simultaneously, the cross-linking leads to improved mechanical resistance of the membranes, which could be further enhanced by an additional thermal treatment. The produced membranes are therefore more suitable for use under harsh conditions and have a better overall performance than the uncross-linked ones.

  10. Temperature changes inside the molar pulp chamber and on the enamel and root surfaces induced by the CO2 laser beam, in vitro

    Science.gov (United States)

    Anic, Ivica; Dzubur, A.; Skala, Karolj; Sutalo, Jozo

    1993-12-01

    The application of the CO2 laser continuous wave to hard dental tissue causes temperature changes on the impact area, on the adjacent area and inside the pulp chamber. The purpose of this study was to investigate the thermal effects induced by the CO2 laser continuous wave, and the temperature flow through adjacent areas. Forty healthy molars, 15 molars with class II amalgam restoration and 10 canines with cervical caries extracted for periodontal reasons were irradiated with laser beam. On the occlusal surface the class I preparation was made just beyond the dentine-enamel junction. Temperature changes were measured at the enamel, root surface and at the cross section of the previously prepared holes 3 mm in diameter which were made 2 mm above the bifurcation level.

  11. Culture characteristics of the atmospheric and room temperature plasma-mutated Spirulina platensis mutants in CO2 aeration culture system for biomass production.

    Science.gov (United States)

    Tan, Yinyee; Fang, Mingyue; Jin, Lihua; Zhang, Chong; Li, He-Ping; Xing, Xin-Hui

    2015-10-01

    For biomass production of Spirulina platensis as feedstock of fermentation, the culture characteristics of three typical mutants of 3-A10, 3-B2 and 4-B3 generated by atmospheric and room temperature plasmas (ARTP) mutagenesis were systematically studied by using CO2 aeration culture system and compared with the wild strain. The specific growth rate of wild strain in the pure air aeration culture system exhibited a 76.2% increase compared with static culture, while the specific growth rates of the 3-A10, 3-B2 and 4-B3 in pure air aeration culture system were increased by 114.4%, 95.9% and 88.2% compared with their static cultures. Compared with static culture, the carbohydrate contents of wild strain, 3-A10, 3-B2 and 4-B3 in pure air aeration culture system dropped plainly by 51.0%, 79.3%, 85.5% and 26.1%. Increase of CO2 concentration enhanced carbohydrate content and productivity. Based on the carbohydrate productivity, the optimal inlet of CO2 concentration in aeration culture was determined to be 12% (v/v). Under this condition, 3-B2 exhibited the highest carbohydrate content (30.7%), CO2 fixation rate (0.120gCO2·g(-1)·d(-1)) and higher growth rate (0.093 g L(-1)·d(-1)), while 3-A10 showed the highest growth rate (0.118 g L(-1)·d(-1)) and higher CO2 fixation rate (0.117gCO2·g(-1)·d(-1)) but low carbohydrate content (24.5%), and 4-B3 showed the highest chlorophyll (Chl) content (3.82 mg·g(-1)). The most outstanding mutant by static culture in terms of growth rate and carbohydrate productivity (3-B2), was also demonstrated by CO2 aeration culture system. This study revealed that the ARTP mutagenesis could generate the S. platensis mutants suitable for CO2 aeration culture aiming at biomass production. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Effects of temperature, CO2/O2 concentrations and light intensity on cellular prolification of microalgae, eugrena gracilis, in aquatic food production of bioregenerative life support systems

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    Microalgae are likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO_2 to O_2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular proliferation of microalgae, Eugrena gracilis, was investigated to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperature (25-33°C), three levels of CO_2 concentration (2-6%), four levels of O_2 concentration (10-25%), and three levels of photosynthetic photon flux density (50-120 μmol m-2 s-1). The number of Eugrena cells in a certain volume of solution was monitored with a microscope under each environment. The multiplication rate of the cells was highest at temperatures of 29°C, 4% CO_2, 20% O_2 and 90 μmol m-2 s-1 PPFD. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO_2 to O_2 under relatively low light intensities in aquatic food production modules.

  13. 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

  14. 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.

  15. 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.

  16. Photoacoustic study of the influence of the cooling temperature on the CO2 emission rate by Carica papaya L. in modified atmosphere

    Science.gov (United States)

    Schramm, D. U.; Sthel, M. S.; da Silva, M. G.; Carneiro, L. O.; Silva, H. R. F.; Martins, M. L. L.; Resende, E. D.; Vitorazi, L.; Vargas, H.

    2005-06-01

    The monitoring of trace gas emitted by papaya fruits and assessments of its mass loss can contribute to improve the conditions for their storage and transport. The C02 emission rate by the papaya fruits, monitored by a commercial infrared-based gas analyzer, was influenced by the temperature and storage time. The fruits stored at temperature of 13 °C accumulated more CO2 inside the PEBD bags than those fruits stored at 6 °C. The loss of mass of the fruits progressively increased with storage time for both temperatures until the saturation of the moisture inside the PEBD bag, been more pronounced at 13 ºC.

  17. Leaf d15N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated [CO2], temperature and low water availability

    Directory of Open Access Journals (Sweden)

    Idoia eAriz

    2015-08-01

    Full Text Available The natural 15N/14N isotope composition (δ15N of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ15N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L. plants were subjected to distinct conditions of [CO2] (400 versus 700 mol mol-1, temperature (ambient versus ambient + 4ºC and water availability (fully watered versus water deficiency - WD. As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ15N in leaves, stems, roots and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP contents detected at 700 mol mol-1 [CO2] and WD conditions. In summary, leaf δ15N provides relevant information integrating parameters which condition plant responsiveness (e.g. photosynthesis, TSP, N demand and water transpiration to environmental conditions.

  18. Effect of the temperature and the CO2 concentration on the behaviour of the citric acid as a scale inhibitor of CaCO3

    Science.gov (United States)

    Blanco, K.; Aponte, H.; Vera, E.

    2017-12-01

    For all Industrial sector is important to extend the useful life of the materials that they use in their process, the scales of CaCO3 are common in situation where fluids are handled with high concentration of ions and besides this temperatures and CO2 concentration dissolved, that scale generates large annual losses because there is a reduction in the process efficiency or corrosion damage under deposit, among other. In order to find new alternatives to this problem, the citric acid was evaluated as scale of calcium carbonate inhibition in critical condition of temperature and concentration of CO2 dissolved. Once the results are obtained it was carried out the statistical evaluation in order to generate an equation that allow to see that behaviour, giving as result, a good efficiency of inhibition to the conditions evaluated the scales of products obtained were characterized through scanning electron microscopy.

  19. Crystal structure and high temperature transport properties of Yb-filled p-type skutterudites YbxCo2.5Fe1.5Sb12

    KAUST Repository

    Dong, Yongkwan

    2014-01-01

    Partially Yb-filled Fe substituted polycrystalline p-type skutterudites with nominal compositions YbxCo2.5Fe1.5Sb 12, with varying filler concentrations x, were synthesized by reacting the constituent elements and subsequent solid state annealing, followed by densification by hot-pressing. The compositions and filling fractions were confirmed with a combination of Rietveld refinement and elemental analysis. Their thermoelectric properties were evaluated from 300 to 800 K. The Seebeck coefficients for the specimens increase with increasing temperature and plateau at around 750 K. The thermal conductivity decreases with increasing Yb filling fraction, and bipolar conduction becomes evident and increases at elevated temperatures. A maximum ZT value of 0.8 was obtained at 750 K for Yb 0.47Co2.6Fe1.4Sb12. The thermoelectric properties and potential for further optimization are discussed in light of our results. © 2013 Elsevier Inc.

  20. Effect of calcination temperature on the structure and catalytic performance of 80Ni20CO/SiO2 catalyst for CO2 methanation

    Science.gov (United States)

    Md Ali, S. A.; Hamid, K. H. K.; Ismail, K. N.

    2017-09-01

    The 80Ni20Co/SiO2 catalysts prepared using co-precipitate and incipient wetness impregnation method were used for production of methane through CO2 methanation reaction between CO and H2 gases. The effect of a range of calcination temperature on the structure and catalytic performance of 80Ni20Co/SiO2 catalyst was investigated using microactivity fixed bed reactor. It was found that the catalyst calcined at 400°C for 4.5 h under air atmosphere has shown the best catalytic performance for CO2 methanation. Characterization of 80Ni20Co/SiO2 catalyst calcined fresh samples was carried out using TPR-H2 analysis, Brunauere Emmette Teller (BET) measurements and X-ray diffraction (XRD. It was observed that calcination temperature influenced the structure, morphology and catalytic performance of the catalysts.

  1. Does the growth response of woody plants to elevated CO2 increase with temperature? A model-oriented meta-analysis.

    Science.gov (United States)

    Baig, Sofia; Medlyn, Belinda E; Mercado, Lina M; Zaehle, Sönke

    2015-12-01

    The temperature dependence of the reaction kinetics of the Rubisco enzyme implies that, at the level of a chloroplast, the response of photosynthesis to rising atmospheric CO2 concentration (Ca ) will increase with increasing air temperature. Vegetation models incorporating this interaction predict that the response of net primary productivity (NPP) to elevated CO2 (eCa ) will increase with rising temperature and will be substantially larger in warm tropical forests than in cold boreal forests. We tested these model predictions against evidence from eCa experiments by carrying out two meta-analyses. Firstly, we tested for an interaction effect on growth responses in factorial eCa  × temperature experiments. This analysis showed a positive, but nonsignificant interaction effect (95% CI for above-ground biomass response = -0.8, 18.0%) between eCa and temperature. Secondly, we tested field-based eCa experiments on woody plants across the globe for a relationship between the eCa effect on plant biomass and mean annual temperature (MAT). This second analysis showed a positive but nonsignificant correlation between the eCa response and MAT. The magnitude of the interactions between CO2 and temperature found in both meta-analyses were consistent with model predictions, even though both analyses gave nonsignificant results. Thus, we conclude that it is not possible to distinguish between the competing hypotheses of no interaction vs. an interaction based on Rubisco kinetics from the available experimental database. Experiments in a wider range of temperature zones are required. Until such experimental data are available, model predictions should aim to incorporate uncertainty about this interaction. © 2015 John Wiley & Sons Ltd.

  2. 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

  3. Influence of elevated temperature and pCO2 on the marine periphytic diatom Navicula distans and its associated organisms in culture

    Digital Repository Service at National Institute of Oceanography (India)

    Baragi, L.V.; Khandeparker, L.; Anil, A.C.

    version: Hydrobiologia (2015) 762:127-142 Influence of elevated temperature and pCO2 on the marine periphytic diatom Navicula distans and its associated organisms in culture Lalita V. Baragi, Lidita Khandeparker, Arga C. Anil* Academy of Scientific... (picoperiphyte and heterotrophic bacteria). Materials and methods Culture conditions Navicula distans, a pennate periphytic diatom, was isolated from a biofilm developed on a glass slide submerged in the waters of Dona Paula Bay located along the west coast...

  4. Parthenium weed (Parthenium hysterophorus L.) and climate change: the effect of CO2concentration, temperature, and water deficit on growth and reproduction of two biotypes.

    Science.gov (United States)

    Nguyen, Thi; Bajwa, Ali Ahsan; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2017-04-01

    Climate change will have a considerable impact upon the processes that moderate weed invasion, in particular to that of parthenium weed (Parthenium hysterophorus L.). This study evaluated the performance of two Australian biotypes of parthenium weed under a range of environmental conditions including soil moisture (100 and 50% of field capacity), atmospheric carbon dioxide (CO 2 ) concentration (390 and 550 ppm), and temperature (35/20 and 30/15 °C/day/night). Measurements were taken upon growth, reproductive output, seed biology (fill, viability and dormancy) and soil seed longevity. Parthenium weed growth and seed output were significantly increased under the elevated CO 2 concentration (550 ppm) and in the cooler (30/15 °C) and wetter (field capacity) conditions. However, elevated CO 2 concentration could not promote growth or seed output when the plants were grown under the warmer (35/20 °C) and wetter conditions. Warm temperatures accelerated the growth of parthenium weed, producing plants with greater height biomass but with a shorter life span. Warm temperatures also affected the reproductive output by promoting both seed production and fill, and promoting seed longevity. Dryer soil conditions (50% of field capacity) also promoted the reproductive output, but did not retain high seed fill or promote seed longevity. Therefore, the rising temperatures, the increased atmospheric CO 2 concentration and the longer periods of drought predicted under climate change scenarios are likely to substantially enhance the growth and reproductive output of these two Australian parthenium weed biotypes. This may facilitate the further invasion of this noxious weed in tropical and sub-tropical natural and agro-ecosystems.

  5. Dynamic Response of CoSb2O6 Trirutile-Type Oxides in a CO2 Atmosphere at Low-Temperatures

    Directory of Open Access Journals (Sweden)

    Alex Guillén-Bonilla

    2014-08-01

    Full Text Available Experimental work on the synthesis of the CoSb2O6 oxide and its CO2 sensing properties is presented here. The oxide was synthesized by a microwave-assisted colloidal method in presence of ethylenediamine after calcination at 600 °C. This CoSb2O6 oxide crystallized in a tetragonal structure with cell parameters  and  Å, and space group P42/mnm. To prove its physical, chemical and sensing properties, the oxide was subjected to a series of tests: Raman spectroscopy, Scanning Electron Microscopy (SEM and impedance (Z measurements. Microstructures, like columns, bars and hollow hemispheres, were observed. For the CO2 sensing test, a thick film of CoSb2O6 was used, measuring the impedance variations on the presence of air/CO2 flows (0.100 sccm/0.100 sccm using AC (alternating current signals in the frequency-range 0.1–100 kHz and low relative temperatures (250 and 300 °C. The CO2 sensing results were quite good.

  6. Responses of methanogenic and methanotrophic communities to elevated atmospheric CO2 and temperature in a paddy field

    Directory of Open Access Journals (Sweden)

    Yuan Liu

    2016-11-01

    Full Text Available Although climate change is predicted to affect methane (CH4 emissions in paddy soil, the dynamics of methanogens and methanotrophs in paddy fields under climate change have not yet been fully investigated. To address this issue, a multifactor climate change experiment was conducted in a Chinese paddy field using the following experimental treatments: (1 enrichment of atmospheric CO2 concentrations (500 ppm, CE, (2 canopy air warming (2°C above the ambient, WA, (3 combined CO2 enrichment and warming (CW, and (4 ambient conditions (CK. We analyzed the abundance of methanogens and methanotrophs, community structures, CH4 production and oxidation potentials, in situ CH4 emissions using real-time PCR, T-RFLP and clone library techniques, as well as biochemical assays. Compared to the control under CE and CW treatments, CH4 production potential, methanogenic gene abundance and soil microbial biomass carbon (SMBC significantly increased; the methanogenic community however remained stable. The canopy air warming treatment only had an effect on CH4 oxidation potential at the ripening stage. Phylogenic analysis indicated that methanogens in the rhizosphere were dominated by Methanosarcina, Methanocellales, Methanobacteriales and Methanomicrobiales, while methanotrophic sequences were classified as Methylococcus, Methylocaldum, Methylomonas, Methylosarcina (Type I and Methylocystis (Type II. However, the relative abundance of Methylococcus (Type I decreased under CE and CW treatments and the relative abundance of Methylocystis (Type II increased. The in situ CH4 fluxes indicated similar seasonal patterns between treatments; both CE and CW increased CH4 emissions. In conclusion results suggest that methanogens and methanotrophs respond differently to elevated atmospheric CO2 concentrations and warming, thus adding insights into the effects of simulated global climate change on CH4 emissions in paddy fields.

  7. The acclimation process of phytoplankton biomass, carbon fixation and respiration to the combined effects of elevated temperature and pCO2in the northern South China Sea.

    Science.gov (United States)

    Gao, Guang; Jin, Peng; Liu, Nana; Li, Futian; Tong, Shanying; Hutchins, David A; Gao, Kunshan

    2017-05-15

    We conducted shipboard microcosm experiments at both off-shore (SEATS) and near-shore (D001) stations in the northern South China Sea (NSCS) under three treatments, low temperature and low pCO 2 (LTLC), high temperature and low pCO 2 (HTLC), and high temperature and high pCO 2 (HTHC). Biomass of phytoplankton at both stations were enhanced by HT. HTHC did not affect phytoplankton biomass at station D001 but decreased it at station SEATS. HT alone increased net primary productivity by 234% at station SEATS and by 67% at station D001 but the stimulating effect disappeared when HC was combined. HT also increased respiration rate by 236% at station SEATS and by 87% at station D001 whereas HTHC reduced it by 61% at station SEATS and did not affect it at station D001. Overall, our findings indicate that the positive effect of ocean warming on phytoplankton assemblages in NSCS could be damped or offset by ocean acidification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effects of elevated atmospheric CO2 concentration and temperature on the soil profile methane distribution and diffusion in rice-wheat rotation system.

    Science.gov (United States)

    Yang, Bo; Chen, Zhaozhi; Zhang, Man; Zhang, Heng; Zhang, Xuhui; Pan, Genxing; Zou, Jianwen; Xiong, Zhengqin

    2015-06-01

    The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments: ambient conditions (CKs), CO2 concentration elevated to ~500 μmol/mol (FACE), temperature elevated by ca. 2°C (T) and combined elevation of CO2 concentration and temperature (FACE+T). A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE+T and T treatments, respectively, at the 7 cm depth during the rice season (pCO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem (p<0.05). Copyright © 2015. Published by Elsevier B.V.

  9. Carbon balance, partitioning and photosynthetic acclimation in fruit-bearing grapevine (Vitis vinifera L. cv. Tempranillo) grown under simulated climate change (elevated CO2, elevated temperature and moderate drought) scenarios in temperature gradient greenhouses.

    Science.gov (United States)

    Salazar-Parra, Carolina; Aranjuelo, Iker; Pascual, Inmaculada; Erice, Gorka; Sanz-Sáez, Álvaro; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Araus, José Luis; Morales, Fermín

    2015-02-01

    Although plant performance under elevated CO2 has been extensively studied in the past little is known about photosynthetic performance changing simultaneously CO2, water availability and temperature conditions. Moreover, despite of its relevancy in crop responsiveness to elevated CO2 conditions, plant level C balance is a topic that, comparatively, has received little attention. In order to test responsiveness of grapevine photosynthetic apparatus to predicted climate change conditions, grapevine (Vitis vinifera L. cv. Tempranillo) fruit-bearing cuttings were exposed to different CO2 (elevated, 700ppm vs. ambient, ca. 400ppm), temperature (ambient vs. elevated, ambient +4°C) and irrigation levels (partial vs. full irrigation). Carbon balance was followed monitoring net photosynthesis (AN, C gain), respiration (RD) and photorespiration (RL) (C losses). Modification of environment (13)C isotopic composition (δ(13)C) under elevated CO2 (from -10.30 to -24.93‰) enabled the further characterization of C partitioning into roots, cuttings, shoots, petioles, leaves, rachides and berries. Irrespective of irrigation level and temperature, exposure to elevated CO2 induced photosynthetic acclimation of plants. C/N imbalance reflected the inability of plants grown at 700ppm CO2 to develop strong C sinks. Partitioning of labeled C to storage organs (main stem and roots) did not avoid accumulation of labeled photoassimilates in leaves, affecting negatively Rubisco carboxylation activity. The study also revealed that, after 20 days of treatment, no oxidative damage to chlorophylls or carotenoids was observed, suggesting a protective role of CO2 either at current or elevated temperatures against the adverse effect of water stress. Copyright © 2014 Elsevier GmbH. All rights reserved.

  10. Assessment of cultivated and wild, weedy rice lines to concurrent changes in CO2 concentration and air temperature: Determining traits for enhanced seed yield with increasing atmospheric CO2

    Science.gov (United States)

    Although a number of studies have examined intra-specific variability in growth and yield to projected atmospheric CO2 concentration, [CO2], none have compared the relative responses of cultivated and wild, weedy crop lines. We quantified the growth and seed yield response for three cultivated ("44...

  11. 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

  12. 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

  13. 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 ...

  14. Co-composting of poultry manure mixtures amended with biochar - The effect of biochar on temperature and C-CO2 emission.

    Science.gov (United States)

    Czekała, Wojciech; Malińska, Krystyna; Cáceres, Rafaela; Janczak, Damian; Dach, Jacek; Lewicki, Andrzej

    2016-01-01

    Biochar as an amendment could have an impact on composting dynamics. This study investigated the effect of the addition of biochar (B) to poultry manure (P) mixed with wheat straw (S) (i.e. P:S, P:S+5%B and P:S+10%B) on temperature and carbon dioxide emission. For temperature studies a modified equation for net degree-hour parameter DHnet (°Chday(-1)) was proposed. The modified equation takes into account ambient temperature. The highest daily temperatures DHnet were observed on day 2 and the mixture with the highest addition of biochar (P:S+10%) reached the max temperature. The period of thermophilic temperatures (40°C>) was shorter for mixtures amended with biochar. The addition of biochar increased C-CO2 emission and the total C-CO2 emission were higher about 6.9% and 7.4% for P:S+5%B and P:S+10%B, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Selectivity and self-diffusion of CO2 and H2 in a mixture on a graphite surface

    NARCIS (Netherlands)

    Trinh, T.T.; Vlugt, T.J.H.; Hägg, M.B.; Bedeaux, D.; Kjelstrup, S.H.

    2013-01-01

    We performed classical molecular dynamics (MD) simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30) and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of

  16. Temperature and CO2 dependency of the photosynthetic photon flux density responses of leaves of Vitis vinifera cvs. Chardonnay and Merlot grown in a hot climate.

    Science.gov (United States)

    Greer, Dennis H

    2017-02-01

    Comparisons of the photosynthetic responses to light and temperature between related cultivars are important to understand how well matched they are to the climate where they are grown. Photosynthetic light responses at a range of leaf temperatures and two CO2 concentrations were measured on leaves of two grapevine cultivars (Vitis vinifera L.) Chardonnay and Merlot vines growing in field conditions. The objective was to assess the interaction between photon flux density (PFD), leaf temperature and CO2 on photosynthesis and to compare the two cultivars. Merlot leaves maintained higher light-saturated rates of photosynthesis at all leaf temperatures compared with the Chardonnay leaves. At low temperatures, a reduced photon yield offset with a high stomatal conductance accounted for the low rates of the Chardonnay leaves. At moderate to high temperatures, photon yields, PFDs at light saturation and stomatal conductances did not account for differences between Merlot and Chardonnay leaves. At elevated CO2 (800 μmol mol-1) concentrations, the differences in photosynthetic performance between the cultivars were enhanced, with 30% higher light saturated rates for Merlot compared with Chardonnay leaves. Merlot berries accumulated more sugar, consistent with published data. These results demonstrate Chardonnay, unlike Merlot, appeared to be poorly matched to the hot climate. However, considering the current market and political trends, low alcoholic wines (and, thus, low sugar grapes) should be preferred. Especially in hot climates, it is always hard to obtain such kind of wines and, thus, the most interesting agronomical challenge, especially for Chardonnay vines could be interpreted in an opposite way. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Interactive effects of increased temperature, pCO2and the synthetic progestin levonorgestrel on the fitness and breeding of the amphipod Gammarus locusta.

    Science.gov (United States)

    Cardoso, P G; Loganimoce, E M; Neuparth, T; Rocha, M J; Rocha, E; Arenas, F

    2017-10-25

    Given the lack of knowledge regarding climate change-chemical exposure interactions, it is vital to evaluate how these two drivers jointly impact aquatic species. Thus, for the first time, we aimed at investigating the combined effects of increased temperature, pCO 2 and the synthetic progestin levonorgestrel on survival, growth, consumption rate and reproduction of the amphipod Gammarus locusta. For that, a full factorial design manipulating temperature [ambient temperature and warming (+4 °C)], pCO 2 [normocapnia and hypercapnia (Δ pH 0.5 units)] and the progestin levonorgestrel (LNG: L1 - 10 ngLL -1 and L2 - 1000 ngLL -1 , control - no progestin and solvent control - vehicle ethanol (0.01%)) was implemented for 21 days. G. locusta was strongly negatively affected by warming, experiencing higher mortality rates (50-80%) than in any other treatments. Instead, growth rates were significantly affected by interactions of LNG with temperature and pCO 2 . It was observed, in the short-term (7d) that under ambient temperature (18 °C) and hypercapnic conditions (pH 7.6), the LNG presence promoted the amphipod's growth, while in the medium-term (21d) this response was not observed. Relative consumption rates (RCRs), during the first week were higher than in the third week. Furthermore, in the first week, RCRs were negatively affected by higher temperature while in the third week, RCRs were negatively affected by acidification. Furthermore, it was observed a negative effect of higher temperature and acidification on G. locusta fecundity, contrarily to LNG. Concluding, the impact of increased temperature and pCO 2 was clearly more adverse for the species than exposure to the synthetic progestin, however, some interactions between the progestin and the climate factors were observed. Thus, in a future scenario of global change, the presence of LNG (and other progestins alike) may modulate to a certain level the effects of climate drivers (and vice-versa) on the

  18. CO2 capture and separation from N2/CH4 mixtures by Co@B8/Co@B8(-) and M@B9/M@B9(-) (M = Ir, Rh, Ru) clusters: a theoretical study.

    Science.gov (United States)

    Wang, Weihua; Zhang, Xiaoxiao; Li, Ping; Sun, Qiao; Li, Zhen; Ren, Cong; Guo, Chao

    2015-01-29

    The discovery of advanced materials with high selectivity and efficiency is essential to realize practical carbon capture and sequestration. Here, we have investigated the interactions of the Co@B8/Co@B8(-) and M@B9/M@B9(-) (M = Ir, Rh, Ru) clusters with CO2, N2, and CH4 gas molecules theoretically. We found that neutral boron clusters have weak interaction with CO2, N2, and CH4 molecules. Similarly, the clusters with their negative charge states have also weak interaction with N2 and CH4 molecules. However, anionic clusters have a strong interaction with CO2, which can be explained by the Lewis acid-base interaction as CO2 (Lewis acid) can gain electron easily from the electron-rich anionic clusters. Moreover, the kinetic stability of the formed complexes after CO2 capture has been validated by ab initio molecular dynamics. In all, the present study demonstrates, for the first time, that the anionic boron wheel ring clusters can be used as potential advanced materials for CO2 capture and separation from flue gas and natural gas mixtures.

  19. One crop breeding cycle from starvation? How engineering crop photosynthesis for rising CO2 and temperature could be one important route to alleviation.

    Science.gov (United States)

    Kromdijk, Johannes; Long, Stephen P

    2016-03-16

    Global climate change is likely to severely impact human food production. This comes at a time when predicted demand for primary foodstuffs by a growing human population and changing global diets is already outpacing a stagnating annual rate of increase in crop productivity. Additionally, the time required by crop breeding and bioengineering to release improved varieties to farmers is substantial, meaning that any crop improvements needed to mitigate food shortages in the 2040s would need to start now. In this perspective, the rationale for improvements in photosynthetic efficiency as a breeding objective for higher yields is outlined. Subsequently, using simple simulation models it is shown how predicted changes in temperature and atmospheric [CO2] affect leaf photosynthetic rates. The chloroplast accounts for the majority of leaf nitrogen in crops. Within the chloroplast about 25% of nitrogen is invested in the carboxylase, Rubisco, which catalyses the first step of CO2 assimilation. Most of the remaining nitrogen is invested in the apparatus to drive carbohydrate synthesis and regenerate ribulose-1:5-bisphosphate (RuBP), the CO2-acceptor molecule at Rubisco. At preindustrial [CO2], investment in these two aspects may have been balanced resulting in co-limitation. At today's [CO2], there appears to be over-investment in Rubisco, and despite the counter-active effects of rising temperature and [CO2], this imbalance is predicted to worsen with global climate change. By breeding or engineering restored optimality under future conditions increased productivity could be achieved in both tropical and temperate environments without additional nitrogen fertilizer. Given the magnitude of the potential shortfall, better storage conditions, improved crop management and better crop varieties will all be needed. With the short time-scale at which food demand is expected to outpace supplies, all available technologies to improve crop varieties, from classical crop breeding to

  20. A novel modelling and experimental technique to predict and measure tissue temperature during CO2 laser stimuli for human pain studies.

    Science.gov (United States)

    Al-Saadi, Mohammed Hamed; Nadeau, V; Dickinson, M R

    2006-07-01

    Laser nerve stimulation is now accepted as one of the preferred methods for applying painful stimuli to human skin during pain studies. One of the main concerns, however, is thermal damage to the skin. We present recent work based on using a CO2 laser with a remote infrared (IR) temperature sensor as a feedback system. A model for predicting the subcutaneous skin temperature derived from the signal from the IR detector allows us to accurately predict the laser parameters, thus maintaining an optimum pain stimulus whilst avoiding dangerous temperature levels, which could result in thermal damage. Another aim is to relate the modelling of the CO2 fibre laser interaction to the pain response and compare these results with practical measurements of the pain threshold for various stimulus parameters. The system will also allow us to maintain a constant skin temperature during the stimulus. Another aim of the experiments underway is to review the psychophysics for pain in human subjects, permitting an investigation of the relationship between temperature and perceived pain.

  1. Low temperature and short-term high-CO2 treatment in postharvest storage of table grapes at two maturity stages: Effects on transcriptome profiling.

    Directory of Open Access Journals (Sweden)

    Raquel Rosales

    2016-07-01

    Full Text Available Table grapes (Vitis vinifera cv. Cardinal are highly perishable and their quality deteriorates during postharvest storage at low temperature mainly because of sensitivity to fungal decay and senescence of rachis. The application of a 3-day CO2 treatment (20 kPa CO2 + 20 kPa O2 + 60 kPa N2 at 0ºC reduced total decay and retained fruit quality in early and late-harvested table grapes during postharvest storage. In order to study the transcriptional responsiveness of table grapes to low temperature and high CO2 levels in the first stage of storage and how the maturity stage affect these changes, we have performed a comparative large-scale transcriptional analysis using the custom-made GrapeGen GeneChip®. In the first stage of storage, low temperature led to a significantly intense change in grape skin transcriptome irrespective of fruit maturity, although there were different changes within each stage. In the case of CO2 treated samples, in comparison to fruit at time zero, only slight differences were observed. Functional enrichment analysis revealed that major modifications in the transcriptome profile of early- and late-harvested grapes stored at 0ºC are linked to biotic and abiotic stress-responsive terms. However, in both cases there is a specific reprogramming of the transcriptome during the first stage of storage at 0ºC in order to withstand the cold stress. Thus, genes involved in gluconeogenesis, photosynthesis, mRNA translation and lipid transport were up-regulated in the case of early-harvested grapes, and genes related to protein folding stability and intracellular membrane trafficking in late-harvested grapes. The beneficial effect of high CO2 treatment maintaining table grape quality seems to be an active process requiring the induction of several transcription factors and kinases in early-harvested grapes, and the activation of processes associated to the maintenance of energy in late-harvested grapes.

  2. CO2 flux geothermometer for geothermal exploration

    Science.gov (United States)

    Harvey, M. C.; Rowland, J. V.; Chiodini, G.; Rissmann, C. F.; Bloomberg, S.; Fridriksson, T.; Oladottir, A. A.

    2017-09-01

    A new geothermometer (TCO2 Flux) is proposed based on soil diffuse CO2 flux and shallow temperature measurements made on areas of steam heated, thermally altered ground above active geothermal systems. This CO2 flux geothermometer is based on a previously reported CO2 geothermometer that was designed for use with fumarole analysis. The new geothermometer provides a valuable additional exploration tool for estimating subsurface temperatures in high-temperature geothermal systems. Mean TCO2 Flux estimates fall within the range of deep drill hole temperatures at Wairakei (New Zealand), Tauhara (New Zealand), Rotokawa (New Zealand), Ohaaki (New Zealand), Reykjanes (Iceland) and Copahue (Argentina). The spatial distribution of geothermometry estimates is consistent with the location of major upflow zones previously reported at the Wairakei and Rotokawa geothermal systems. TCO2 Flux was also evaluated at White Island (New Zealand) and Reporoa (New Zealand), where limited sub-surface data exists. Mode TCO2 Flux at White Island is high (320 °C), the highest of the systems considered in this study. However, the geothermometer relies on mineral-water equilibrium in neutral pH reservoir fluids, and would not be reliable in such an active and acidic environment. Mean TCO2 Flux at Reporoa (310 °C) is high, which indicates Reporoa has a separate upflow from the nearby Waiotapu geothermal system; an outflow from Waiotapu would not be expected to have such high temperature.

  3. [The effect of light and temperature of the CO2 exchange of different life forms in the ground vegetation of a montane beech forest].

    Science.gov (United States)

    Schulze, E-D

    1972-09-01

    In a montane beech (Fagus sylvatica) forest the influence of the climatic factors, light and temperature, on net photosynthesis and on the CO2 balance of the ground vegetation was investigated. The total turnover of carbon was calculated. Species studied included: Athyrium filix-femina, Oxalis acetosella, Luzula luzuloides, Deschampsia flexuosa and young plants of Fagus sylvatica. 1. The light compensation point in all spp. is between 300 and 500 lux except for D. flexuosa where it is 2 klx. Light saturation is attained at 2-3 klx for A. filix-femina, at 5-6 klx for O. acetosella, and at 6-7 klx for L. luzuloides and F. sylvatica. The net photosynthesis of D. flexuosa increases linearly upto 12 klx. This plant, therefore, is more closely related to plants with high light requirements than all the other species under experiment. 2. The maximum rates of net photosynthesis in O. acetosella and A. filix-femina are higher than in all the other plants, independent of the reference system. Per unit dry weight they even attain rates of CO2 uptake (22-27 mg CO2/gdw·h) known from herbs under the much better light conditions of an open habitat. F. sylvatica and L. luzuloides exhibit per unit dry weight only 30% of this rate and D. flexuosa 25%. On a leaf surface area and chlorophyll content basis differences are smaller: F. sylvatics attains 75%, L. luzuloides reaches 50% and D. flexuosa only 30% of the maximal rates of net photosynthesis of O. acetosella and A. filix-femina. The higher CO2 uptake of O. acetosella and A. filix-femina points to a better adaptation of their photosynthetic apparatus in comparison to all the other species of the same habitat. 3. At light saturation the temperature optimum of A. filix-femina and O. acetosella covers a smaller range at lower temperatures than was found in the other species. These attain almost maximal rates of net photosynthesis over the whole range of temperatures of their natural habitat. At decreasing light intensities the

  4. Visualizing MOF Mixed Matrix Membranes at the Nanoscale : Towards Structure-Performance Relationships in CO 2 /CH 4 Separation Over NH 2 -MIL-53(Al)@PI

    NARCIS (Netherlands)

    Rodenas, T.; Van Dalen, M.; Garcia-Perez, E.; Serra-Crespo, P.; Zornoza, B.; Kapteijn, F.; Gascon, J.

    2013-01-01

    Mixed matrix membranes (MMMs) composed of metal organic framework (MOF) fi llers embedded in a polymeric matrix represent a promising alternative for CO 2 removal from natural gas and biogas. Here, MMMs based on NH 2 -MIL-53(Al) MOF and polyimide are successfully synthesized with MOF loadings up to

  5. Unusual isotopic composition of C-CO2 from sterilized soil microcosms: a new way to separate intracellular from extracellular respiratory metabolisms.

    Science.gov (United States)

    Kéraval, Benoit; Alvarez, Gaël; Lehours, Anne Catherine; Amblard, Christian; Fontaine, Sebastien

    2015-04-01

    The mineralization of organic C requires two main steps. First, microorganisms secrete exoenzymes in soil in order to depolymerize plant and microbial cell walls and release soluble substrates for microbial assimilation. The second step of mineralization, during which C is released as CO2, implies the absorption and utilization of solubilized substrates by microbial cells with the aim to produce energy (ATP). In cells, soluble substrates are carried out by a cascade of respiratory enzymes, along which protons and electrons are transferred from a substrate to oxygen. Given the complexity of this oxidative metabolism and the typical fragility of respiratory enzymes, it is traditionally considered that respiration (second step of C mineralization process) is strictly an intracellular metabolism process. The recurrent observations of substantial CO2 emissions in soil microcosms where microbial cells have been reduced to extremely low levels challenges this paradigm. In a recent study where some respiratory enzymes have shown to function in an extracellular context in soils, Maire et al. (2013) suggested that an extracellular oxidative metabolism (EXOMET) substantially contributes to CO2 emission from soils. This idea is supported by the recent publication of Blankinship et al., 2014 who showed the presence of active enzymes involved in the Krebs cycle on soil particles. Many controversies subsist in the scientific community due to the presence of non-proliferating but morphologically intact cells after irradiation that could substantially contribute to those soil CO2 emissions. To test whether a purely extracellular oxidative metabolism contribute to soil CO2 emissions, we combined high doses of gamma irradiations to different time of soil autoclaving. The presence of active and non-active cells in soil was checked by DNA and RNA extraction and by electronic microscopy. None active cells (RNA-containing cells) were detectable after irradiation, but some morphological

  6. One‐Step Reforming of CO2 and CH4 into High‐Value Liquid Chemicals and Fuels at Room Temperature by Plasma‐Driven Catalysis

    Science.gov (United States)

    Wang, Li; Yi, Yanhui; Wu, Chunfei; Guo, Hongchen

    2017-01-01

    Abstract The conversion of CO2 with CH4 into liquid fuels and chemicals in a single‐step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one‐step process from CO2 and CH4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50–60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH4 and CO2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process. PMID:28842938

  7. One-Step Reforming of CO2 and CH4 into High-Value Liquid Chemicals and Fuels at Room Temperature by Plasma-Driven Catalysis.

    Science.gov (United States)

    Wang, Li; Yi, Yanhui; Wu, Chunfei; Guo, Hongchen; Tu, Xin

    2017-10-23

    The conversion of CO2 with CH4 into liquid fuels and chemicals in a single-step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one-step process from CO2 and CH4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50-60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH4 and CO2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  8. 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

  9. 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.

  10. 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

  11. Regulation of anthrax toxin activator gene (atxA) expression in Bacillus anthracis: temperature, not CO2/bicarbonate, affects AtxA synthesis.

    OpenAIRE

    Dai, Z; Koehler, T M

    1997-01-01

    Anthrax toxin gene expression in Bacillus anthracis is dependent on the presence of atxA, a trans-acting regulatory gene located on the resident 185-kb plasmid pXO1. In atxA+ strains, expression of the toxin genes (pag, lef, and cya) is enhanced by two physiologically significant signals: elevated CO2/bicarbonate and temperature. To determine whether increased toxin gene expression in response to these signals is associated with increased atxA expression, we monitored steady-state levels of a...

  12. Effects of elevated atmospheric CO2, prolonged summer drought and temperature increase on N2O and CH4 fluxes in a temperate heathland

    DEFF Research Database (Denmark)

    Carter, Mette Sustmann; Ambus, Per; Albert, Kristian Rost

    2011-01-01

    In temperate regions, climate change is predicted to increase annual mean temperature and intensify the duration and frequency of summer droughts, which together with elevated atmospheric carbon dioxide (CO2) concentrations, may affect the exchange of nitrous oxide (N2O) and methane (CH4) between...... terrestrial ecosystems and the atmosphere. We report results from the CLIMAITE experiment, where the effects of these three climate change parameters were investigated solely and in all combinations in a temperate heathland. Field measurements of N2O and CH4 fluxes took place 1–2 years after the climate...

  13. Growth of mature boreal Norway spruce was not affected by elevated [CO(2)] and/or air temperature unless nutrient availability was improved.

    Science.gov (United States)

    Sigurdsson, Bjarni D; Medhurst, Jane L; Wallin, Göran; Eggertsson, Olafur; Linder, Sune

    2013-11-01

    The growth responses of mature Norway spruce (Picea abies (L.) Karst.) trees exposed to elevated [CO(2)] (CE; 670-700 ppm) and long-term optimized nutrient availability or elevated air temperature (TE; ±3.9 °C) were studied in situ in northern Sweden in two 3 year field experiments using 12 whole-tree chambers in ca. 40-year-old forest. The first experiment (Exp. I) studied the interactions between CE and nutrient availability and the second (Exp. II) between CE and TE. It should be noted that only air temperature was elevated in Exp. II, while soil temperature was maintained close to ambient. In Exp. I, CE significantly increased the mean annual height increment, stem volume and biomass increment during the treatment period (25, 28, and 22%, respectively) when nutrients were supplied. There was, however, no significant positive CE effect found at the low natural nutrient availability. In Exp. II, which was conducted at the natural site fertility, neither CE nor TE significantly affected height or stem increment. It is concluded that the low nutrient availability (mainly nitrogen) in the boreal forests is likely to restrict their response to the continuous rise in [CO(2)] and/or TE.

  14. Spin valve-like magnetic tunnel diode exhibiting giant positive junction magnetoresistance at low temperature in Co2MnSi/SiO2/p-Si heterostructure

    Science.gov (United States)

    Maji, Nilay; Kar, Uddipta; Nath, T. K.

    2018-02-01

    The rectifying magnetic tunnel diode has been fabricated by growing Co2MnSi (CMS) Heusler alloy film carefully on a properly cleaned p-Si (100) substrate with the help of electron beam physical vapor deposition technique and its structural, electrical and magnetic properties have been experimentally investigated in details. The electronic- and magneto-transport properties at various isothermal conditions have been studied in the temperature regime of 78-300 K. The current-voltage ( I- V) characteristics of the junction show an excellent rectifying magnetic tunnel diode-like behavior throughout that temperature regime. The current ( I) across the junction has been found to decrease with the application of a magnetic field parallel to the plane of the CMS film clearly indicating positive junction magnetoresistance (JMR) of the heterostructure. When forward dc bias is applied to the heterostructure, the I- V characteristics are highly influenced on turning on the field B = 0.5 T at 78 K, and the forward current reduces abruptly (99.2% current reduction at 3 V) which is nearly equal to the order of the magnitude of the current observed in the reverse bias. Hence, our Co2MnSi/SiO2/p-Si heterostructure can perform in off ( I off)/on ( I on) states with the application of non-zero/zero magnetic field like a spin valve at low temperature (78 K).

  15. Temperature modulates the response of the thermophilous sea urchin Arbacia lixula early life stages to CO2-driven acidification.

    Science.gov (United States)

    Gianguzza, Paola; Visconti, Giulia; Gianguzza, Fabrizio; Vizzini, Salvatrice; Sarà, Gianluca; Dupont, Sam

    2014-02-01

    The increasing abundances of the thermophilous black sea urchin Arbacia lixula in the Mediterranean Sea are attributed to the Western Mediterranean warming. However, few data are available on the potential impact of this warming on A. lixula in combination with other global stressors such as ocean acidification. The aim of this study is to investigate the interactive effects of increased temperature and of decreased pH on fertilization and early development of A. lixula. This was tested using a fully crossed design with four temperatures (20, 24, 26 and 27 °C) and two pH levels (pHNBS 8.2 and 7.9). Temperature and pH had no significant effect on fertilization and larval survival (2d) for temperature <27 °C. At 27 °C, the fertilization success was very low (<1%) and all larvae died within 2d. Both temperature and pH had effects on the developmental dynamics. Temperature appeared to modulate the impact of decreasing pH on the % of larvae reaching the pluteus stage leading to a positive effect (faster growth compared to pH 8.2) of low pH at 20 °C, a neutral effect at 24 °C and a negative effect (slower growth) at 26 °C. These results highlight the importance of considering a range of temperatures covering today and the future environmental variability in any experiment aiming at studying the impact of ocean acidification. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream

    Science.gov (United States)

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung; Parks, II, James E.

    2017-01-10

    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

  17. Temperature Dependence of Near-Infrared CO_2 Line Shapes Measured by Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Ghysels, Mélanie; Fleisher, Adam J.; Liu, Qingnan; Hodges, Joseph T.

    2017-06-01

    We present high signal-to-noise ratio, mode-by-mode cavity ring-down spectroscopy (CRDS) line shape measurements of air-broadened transitions in the 30013 → 0001 band of ^{12}C^{16}O_2 located near λ = 1.6 μm. Absorption spectra were acquired from (230-290) K with a variable-temperature spectrometer developed in the framework of the NASA Orbiting Carbon Observatory-2 Mission to improve our understanding of carbon dioxide and oxygen line shape parameters. This system comprises a monolithic, thermally stabilized two-mirror, optical resonator exhibiting a mode stability of 200 kHz and a minimum detectable absorption coefficient of 10^{-11} cm^{-1}. Observed spectra were modeled the using the recently recommended Hartmann-Tran line profile (HTP) (and several of its limiting cases) which includes the effects of Dicke narrowing, speed dependent broadening, correlation between velocity- and phase-changing collisions and first-order line mixing effects. At fixed temperature, line shape parameters were determined by constrained multispectrum fitting of spectra acquired over the pressure range (30 - 300) Torr. For each transition considered, analysis of the temperature dependence of the fitted line shape parameters yielded the pressure-broadening temperature exponent and speed dependence parameter, where the latter quantity was found to be in good agreement with theoretical values consistent with the HTP model. Tennyson, et al., Pure Appl. Chem. 86, (2014) 1931

  18. A Comparison of Arrhenius and Macromolecular Rate Theory for Predicting Temperature Responses of Soil CO2 Production

    Science.gov (United States)

    Alster, C. J.; Koyama, A.; Johnson, N. G.; von Fischer, J.

    2015-12-01

    Soil microbes catalyze many key ecosystem functions, including soil respiration, and are thus important for understanding global carbon cycles and other biogeochemical cycles. One important component in predicting rates of respiration is determining how microbial communities respond to temperature. A range of models have been developed for determining temperature sensitivity of soil biological activities, most of which are based on the Arrhenius equation. This equation predicts an exponential increase in rate with temperature, despite field and laboratory results suggesting a temperature optimum below the denaturation point. Recently, Schipper et al. (2014) developed a novel theory, Macromolecular Rate Theory (MMRT), which explains this trend due to heat capacity (CP) changes associated with enzymes. We applied MMRT to respiration data collected using a reciprocal transplant design with soils from three different sites across the U.S. Great Plains to isolate the effects of microbial community type from edaphic factors. We found that MMRT provided a better fit to the data than Arrhenius in 8 out of the 9 soil x inocula combinations. Our analysis revealed that the microbial communities have distinct CP values largely independent of soil type. These results have significant implications for fundamental understanding of microbial enzyme dynamics in soils as well as for ecosystem and global carbon modeling.

  19. The space-time continuum: the effects of elevated CO2 and temperature on trees and the importance of scaling.

    Science.gov (United States)

    Way, Danielle A; Oren, Ram; Kroner, Yulia

    2015-06-01

    To predict how forests will respond to rising temperatures and atmospheric CO₂ concentrations, we need to understand how trees respond to both of these environmental factors. In this review, we discuss the importance of scaling, moving from leaf-level responses to those of the canopy, and from short-term to long-term responses of vegetation to climate change. While our knowledge of leaf-level, instantaneous responses of photosynthesis, respiration, stomatal conductance, transpiration and water-use efficiency to elevated CO₂ and temperature is quite good, our ability to scale these responses up to larger spatial and temporal scales is less developed. We highlight which physiological processes are least understood at various levels of study, and discuss how ignoring differences in the spatial or temporal scale of a physiological process impedes our ability to predict how forest carbon and water fluxes forests will be altered in the future. We also synthesize data from the literature to show that light respiration follows a generalized temperature response across studies, and that the light compensation point of photosynthesis is reduced by elevated growth CO₂. Lastly, we emphasize the need to move beyond single factorial experiments whenever possible, and to combine both CO₂ and temperature treatments in studies of tree performance. © 2015 John Wiley & Sons Ltd.

  20. Does elevated CO2 protect photosynthesis from damage by high temperature via modifying leaf water status in maize seedlings?

    Science.gov (United States)

    Because high temperatures under field conditions are associated with high water vapor pressure deficits, often causing leaf desiccation, we hypothesized that decreased stomatal conductance at elevated carbon dioxide may increase leaf water potential and protect photosynthesis in C4 species from dama...

  1. Linking phytoplankton community size composition with temperature, plankton food web structure and sea–air CO2 flux

    DEFF Research Database (Denmark)

    Hilligsøe, Karen Marie; Richardson, Katherine; Bendtsen, Jørgen

    2011-01-01

    Data collected at open water stations (depth>400m) in all major ocean basins in 2006–2008 are used to examine the relationship between the size structure of the phytoplankton community (determined by size fractionated chlorophyll filtration), temperature and inorganic nutrient availability. A sig...

  2. Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; Manohar S. Sohal; Lila Mulloth; Bernadette Luna; Morgan B. Abney

    2010-03-01

    NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developed and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon

  3. Expression Profiles and DNA-Binding Affinity of Five ERF Genes in Bunches of Vitis vinifera cv. Cardinal Treated with High Levels of CO2 at Low Temperature.

    Science.gov (United States)

    Romero, Irene; Vazquez-Hernandez, Maria; Escribano, M I; Merodio, Carmen; Sanchez-Ballesta, M T

    2016-01-01

    Ethylene response factors (ERFs) play an important role in plants by regulating defense response through interaction with various stress pathways. After harvest, table grapes (Vitis vinifera L.) are subject to a range of problems associated with postharvest storage at 0°C, such as fungal attack, water loss and rachis browning. The application of a 3-day high CO2 treatment maintained fruit quality and activated the induction of transcription factors belonging to different families such as ERF. In this paper, we have isolated five VviERFs from table grapes cv. Cardinal, whose deduced amino acid sequence contained the conserved apetalous (AP2)/ERF domain. The phylogeny and putative conserved motifs in VviERFs were analyzed and compared with those previously reported in Vitis. VviERFs-c gene expression was studied by quantitative real-time RT-PCR in the different tissues of bunches stored at low temperature and treated with high levels of CO2. The results showed that in most of the tissues analyzed, VviERFs-c gene expression was induced by the storage under normal atmosphere although the application of high levels of CO2 caused a greater increase in the VviERFs-c transcript accumulation. The promoter regions of two PRs (pathogenesis related proteins), Vcchit1b and Vcgns1, were obtained and the in silico analysis revealed the presence of a cis-acting ethylene response element (GCC box). In addition, expression of these two PR genes was analyzed in the pulp and rachis of CO2-treated and non-treated table grapes stored at 0°C and results showed significant correlations with VviERF2-c and VviERF6L7-c gene expression in rachis, and between VviERF11-c and Vcchit1b in pulp. Finally by using electro mobility shift assays, we denoted differences in binding of VviERFs to the GCC sequences present in the promoters of both PRs, with VviERF6L7-c being the only member which did not bind to any tested probe. Overall, our results suggest that the beneficial effect of high CO2

  4. Expression Profiles and DNA-Binding Affinity of Five ERF Genes in Bunches of Vitis vinifera cv. Cardinal Treated with High Levels of CO2 at Low Temperature

    Science.gov (United States)

    Romero, Irene; Vazquez-Hernandez, Maria; Escribano, M. I.; Merodio, Carmen; Sanchez-Ballesta, M. T.

    2016-01-01

    Ethylene response factors (ERFs) play an important role in plants by regulating defense response through interaction with various stress pathways. After harvest, table grapes (Vitis vinifera L.) are subject to a range of problems associated with postharvest storage at 0°C, such as fungal attack, water loss and rachis browning. The application of a 3-day high CO2 treatment maintained fruit quality and activated the induction of transcription factors belonging to different families such as ERF. In this paper, we have isolated five VviERFs from table grapes cv. Cardinal, whose deduced amino acid sequence contained the conserved apetalous (AP2)/ERF domain. The phylogeny and putative conserved motifs in VviERFs were analyzed and compared with those previously reported in Vitis. VviERFs-c gene expression was studied by quantitative real-time RT-PCR in the different tissues of bunches stored at low temperature and treated with high levels of CO2. The results showed that in most of the tissues analyzed, VviERFs-c gene expression was induced by the storage under normal atmosphere although the application of high levels of CO2 caused a greater increase in the VviERFs-c transcript accumulation. The promoter regions of two PRs (pathogenesis related proteins), Vcchit1b and Vcgns1, were obtained and the in silico analysis revealed the presence of a cis-acting ethylene response element (GCC box). In addition, expression of these two PR genes was analyzed in the pulp and rachis of CO2-treated and non-treated table grapes stored at 0°C and results showed significant correlations with VviERF2-c and VviERF6L7-c gene expression in rachis, and between VviERF11-c and Vcchit1b in pulp. Finally by using electro mobility shift assays, we denoted differences in binding of VviERFs to the GCC sequences present in the promoters of both PRs, with VviERF6L7-c being the only member which did not bind to any tested probe. Overall, our results suggest that the beneficial effect of high CO2

  5. Post combustion CO2 capture using zeolite membrane

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.

    2017-03-01

    Carbon dioxide emission is the major cause of global warming. It is believed that reducing carbon dioxide emission from fossil fuel combustion is the most effective way to prevent global warming. Membrane separation using zeolites offers energy efficient way to capture CO2 compared to conventional separation techniques such as amine absorption. In general, flue gas has high temperature and mainly consisting nitrogen, water, CO2 and traces of other compounds. These compounds have similar kinetic diameter thus simple Knudsen diffusion cannot separate CO2 from flue gas mixture. Zeolite is beneficial to post-combustion CO2 capture not only because it can withstand high temperature but also because of its unique sorption-diffusion separation mechanism. However, zeolite membrane faced a challenge to make it easier to fabricate. Relatively high zeolite price is also a significant hurdle to broaden its application. In order to relieve this problem, a lot of modifications have been performed. Zeolite modification by polymer has gained increased attention for post-combustion CO2 capture application. To present a clear background, this work will present modifications of zeolite membrane using polymer. Special attention will be given to composite and mixed matrix membrane configuration. Several drawbacks and problems encountered will also be discussed.

  6. Temperature-responsive chromatography for the separation of biomolecules.

    Science.gov (United States)

    Kanazawa, Hideko; Okano, Teruo

    2011-12-09

    Temperature-responsive chromatography for the separation of biomolecules utilizing poly(N-isopropylacrylamide) (PNIPAAm) and its copolymer-modified stationary phase is performed with an aqueous mobile phase without using organic solvent. The surface properties and function of the stationary phase are controlled by external temperature changes without changing the mobile-phase composition. This analytical system is based on nonspecific adsorption by the reversible transition of a hydrophilic-hydrophobic PNIPAAm-grafted surface. The driving force for retention is hydrophobic interaction between the solute molecules and the hydrophobized polymer chains on the stationary phase surface. The separation of the biomolecules, such as nucleotides and proteins was achieved by a dual temperature- and pH-responsive chromatography system. The electrostatic and hydrophobic interactions could be modulated simultaneously with the temperature in an aqueous mobile phase, thus the separation system would have potential applications in the separation of biomolecules. Additionally, chromatographic matrices prepared by a surface-initiated atom transfer radical polymerization (ATRP) exhibit a strong interaction with analytes, because the polymerization procedure forms a densely packed polymer, called a polymer brush, on the surfaces. The copolymer brush grafted surfaces prepared by ATRP was an effective tool for separating basic biomolecules by modulating the electrostatic and hydrophobic interactions. Applications of thermally responsive columns for the separations of biomolecules are reviewed here. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Effect of drainage on CO2 exchange patterns in an intensively managed peat pasture

    NARCIS (Netherlands)

    Dirks, B.O.M.; Hensen, A.; Goudriaan, J.

    2000-01-01

    Eddy correlation measurements of CO2 exchange were made in intensively managed peat pastures at 2 different groundwater tables during most of a growing season. F was separated into a respiratory and an assimilatory CO2 flux. The fit of the Arrhenius temperature response to Fr showed that Fr was

  8. Rapid responses of mesophyll conductance to changes of CO2 concentration, temperature and irradiance are affected by N supplements in rice.

    Science.gov (United States)

    Xiong, Dongliang; Liu, Xi; Liu, Limin; Douthe, Cyril; Li, Yong; Peng, Shaobing; Huang, Jianliang

    2015-12-01

    Photosynthesis in C3 plants is significantly limited by mesophyll conductance (gm ), which can vary with leaf anatomical traits and nitrogen (N) supplements. Several studies have investigated the response of gm to N supplements; however, none examined the implications of N supplements on the response of gm to rapid environmental changes. Here we investigated the effect of N supplement on gm and the response of gm to change of CO2 , temperature and irradiance in rice. High N supplement (HN) increased mesophyll cell wall surface area and chloroplast surface area exposed to intercellular airspace per leaf area, and reduced cell wall thickness. These changes resulted in increased gm . The gm of leaves with HN was more sensitive to changes in CO2 concentration, temperature and irradiance. The difference in leaf structural features between low N supplement and HN indicates that a rapid change in gm is related to the regulation of diffusion through biological membranes rather than leaf structural features. These results will contribute to an understanding of the determinants of gm response to rapid changes in environmental factors. © 2015 John Wiley & Sons Ltd.

  9. 10 MW Supercritical CO2 Turbine Test

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, Craig

    2014-01-29

    The Supercritical CO2 Turbine Test project was to demonstrate the inherent efficiencies of a supercritical carbon dioxide (s-CO2) power turbine and associated turbomachinery under conditions and at a scale relevant to commercial concentrating solar power (CSP) projects, thereby accelerating the commercial deployment of this new power generation technology. The project involved eight partnering organizations: NREL, Sandia National Laboratories, Echogen Power Systems, Abengoa Solar, University of Wisconsin at Madison, Electric Power Research Institute, Barber-Nichols, and the CSP Program of the U.S. Department of Energy. The multi-year project planned to design, fabricate, and validate an s-CO2 power turbine of nominally 10 MWe that is capable of operation at up to 700°C and operates in a dry-cooled test loop. The project plan consisted of three phases: (1) system design and modeling, (2) fabrication, and (3) testing. The major accomplishments of Phase 1 included: Design of a multistage, axial-flow, s-CO2 power turbine; Design modifications to an existing turbocompressor to provide s-CO2 flow for the test system; Updated equipment and installation costs for the turbomachinery and associated support infrastructure; Development of simulation tools for the test loop itself and for more efficient cycle designs that are of greater commercial interest; Simulation of s-CO2 power cycle integration into molten-nitrate-salt CSP systems indicating a cost benefit of up to 8% in levelized cost of energy; Identification of recuperator cost as a key economic parameter; Corrosion data for multiple alloys at temperatures up to 650ºC in high-pressure CO2 and recommendations for materials-of-construction; and Revised test plan and preliminary operating conditions based on the ongoing tests of related equipment. Phase 1 established that the cost of the facility needed to test the power turbine at its full power and temperature would exceed the planned funding for Phases 2 and 3. Late

  10. GC/MS Gas Separator Operates At Lower Temperatures

    Science.gov (United States)

    Sinha, Mahadeva P.; Gutnikov, George

    1991-01-01

    Experiments show palladium/silver tube used to separate hydrogen carrier gas from gases being analyzed in gas-chromatography/mass-spectrometry (GC/MS) system functions satisfactorily at temperatures as low as 70 to 100 degrees C. Less power consumed, and catalytic hydrogenation of compounds being analyzed diminished. Because separation efficiency high even at lower temperatures, gas load on vacuum pump of mass spectrometer kept low, permitting use of smaller pump. These features facilitate development of relatively small, lightweight, portable GC/MS system for such uses as measuring concentrations of pollutants in field.

  11. Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal

    Science.gov (United States)

    Siriwardane, Ranjani V; Fisher, II, James C

    2013-12-31

    The disclosure utilizes a hydroxide sorbent for humidification and CO.sub.2 removal from a gaseous stream comprised of CO and CO.sub.2 prior to entry into a water-gas-shift reactor, in order to decrease CO.sub.2 concentration and increase H.sub.2O concentration and shift the water-gas shift reaction toward the forward reaction products CO.sub.2 and H.sub.2. The hydroxide sorbent may be utilized for absorbtion of CO.sub.2 exiting the water-gas shift reactor, producing an enriched H.sub.2 stream. The disclosure further provides for regeneration of the hydroxide sorbent at temperature approximating water-gas shift conditions, and for utilizing H.sub.2O product liberated as a result of the CO.sub.2 absorption.

  12. Who's driving?: Separating Fire, CO2, and Climate Change Influences on Vegetation and Carbon Dynamics on MC2 Results for Western Oregon and Washington, United States

    Science.gov (United States)

    Sheehan, T.; Bachelet, D. M.; Ferschweiler, K.

    2016-12-01

    For Oregon and Washington west of the Cascade Mountain crest, results from the MC2 global dynamic vegetation model have projected a shift in potential vegetation type from predominantly conifer to predominantly mixed forest over the 21st century, with a shift from mixed to conifer in some areas. Carbon stocks have been projected to fall over this period. We ran MC2 using the CCSM4 RCP 8.5 climate future downscaled to 2.5 arc minute resolution with 5 different configurations: no fire; assumed ignitions without fire suppression; assumed ignitions with fire suppression; assumed ignitions with fire suppression and with CO2 concentration held at the preindustrial level; and stochastic ignitions without fire suppression. Results show that vegetation change is the result of climate change alone, while carbon is influenced by both fire occurrence and CO2-induced increased water use efficiency. While model results do not indicate a large change in carbon dynamics concomitant with the shift in vegetation, it is reasonable to expect that a change in conditions resulting in such a change in vegetation type would stress the existing vegetation resulting in some mortality and loss of live carbon.

  13. Thermoacoustic mixture separation with an axial temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Geller, Drew W [Los Alamos National Laboratory; Swift, Gregory A [Los Alamos National Laboratory

    2008-01-01

    The theory of thermoacoustic mixture separation is extended to include the effect of a nonzero axial temperature gradient. The analysis yields a new term in the second-order mole flux that is proportional to the temperature gradient and to the square of the volumetric velocity and is independent of the phasing of the wave. Because of this new term, thermoacoustic separation stops at a critical temperature gradient and changes direction above that gradient. For a traveling wave, this gradient is somewhat higher than that predicted by a simple four-step model. An experiment tests the theory for temperature gradients from 0 to 416 K/m in 50-50 He-Ar mixtures.

  14. Membrane Technologies for CO2 Capture

    NARCIS (Netherlands)

    Simons-Fischbein, K.

    2010-01-01

    This thesis investigates the potential of membrane technology for the effective CO2/CH4 separation. The work focuses on two different membrane processes to accomplish the separation: 1) The use of a gas-liquid membrane contactor for the selective absorption of CO2 from CH4 2) The use of thin, dense

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

    KAUST Repository

    Swaidan, Raja

    2013-11-01

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

  16. Simultaneous remote measurement of CO2 concentration, humidity and temperature with a matrix of optical fiber sensors

    Science.gov (United States)

    Wysokiński, Karol; Filipowicz, Marta; Stańczyk, Tomasz; Lipiński, Stanisław; Napierała, Marek; Murawski, Michał; Nasiłowski, Tomasz

    2017-10-01

    A matrix of optical fiber sensors eligible for remote measurements is reported in this paper. The aim of work was to monitor the air quality with a device, which does not need any electricity on site of the measurement. The matrix consists of several sensors detecting carbon dioxide concentration, relative humidity and temperature. Sensors utilize active optical materials, which change their color when exposed to varied conditions. All the sensors are powered with standard light emitting diodes. Light is transmitted by an optical fiber from the light source and then it reaches the active layer which changes its color, when the conditions change. This results in a change of attenuation of light passing through the active layer. Modified light is then transmitted by another optical fiber to the detector, where simple photoresistor is used. It is powered by a stabilized DC power supply and the current is measured. Since no expensive elements are needed to manufacture such a matrix of sensors, its price may be competitive to the price of the devices already available on the market, while the matrix also exhibits other valuable properties.

  17. A Reversed Photosynthesis-like Process for Light-Triggered CO2 Capture, Release, and Conversion.

    Science.gov (United States)

    Wang, Dingguan; Liao, Shenglong; Zhang, Shiming; Wang, Yapei

    2017-06-22

    Materials for CO2 capture have been extensively exploited for climate governance and gas separation. However, their regeneration is facing the problems of high energy cost and secondary CO2 contamination. Herein, a reversed photosynthesis-like process is proposed, in which CO2 is absorbed in darkness while being released under light illumination. The process is likely supplementary to natural photosynthesis of plants, in which, on the contrary, CO2 is released during the night. Remarkably, the material used here is able to capture 9.6 wt.% CO2 according to its active component. Repeatable CO2 capture at room temperature and release under light irradiation ensures its convenient and cost-effective regeneration. Furthermore, CO2 released from the system is successfully converted into a stable compound in tandem with specific catalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nanostructured LnBaCo2O6− (Ln = Sm, Gd with layered structure for intermediate temperature solid oxide fuel cell cathodes

    Directory of Open Access Journals (Sweden)

    Augusto E. Mejía Gómez

    2017-04-01

    Full Text Available In this work, we present the combination of two characteristics that are beneficial for solid oxide fuel cell (SOFC cathodic performance in one material. We developed and evaluated for the first time nanostructured layered perovskites of formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respectively as SOFC cathodes, finding promising electrochemical properties in the intermediate temperature range. We obtained those nanostructures by using porous templates to confine the chemical reagents in regions of 200-800 nm. The performance of nanostructured SBCO and GBCO cathodes was analyzed by electrochemical impedance spectroscopy technique under different operating conditions using Gd2O3-doped CeO2 as electrolyte. We found that SBCO cathodes displayed lower area-specific resistance than GBCO ones, because bulk diffusion of oxide ions is enhanced in the former. We also found that cathodes synthesized using smaller template pores exhibited better performance.

  19. Controlling Cooperative CO2Adsorption in Diamine-Appended Mg2(dobpdc) Metal-Organic Frameworks.

    Science.gov (United States)

    Siegelman, Rebecca L; McDonald, Thomas M; Gonzalez, Miguel I; Martell, Jeffrey D; Milner, Phillip J; Mason, Jarad A; Berger, Adam H; Bhown, Abhoyjit S; Long, Jeffrey R

    2017-08-02

    In the transition to a clean-energy future, CO 2 separations will play a critical role in mitigating current greenhouse gas emissions and facilitating conversion to cleaner-burning and renewable fuels. New materials with high selectivities for CO 2 adsorption, large CO 2 removal capacities, and low regeneration energies are needed to achieve these separations efficiently at scale. Here, we present a detailed investigation of nine diamine-appended variants of the metal-organic framework Mg 2 (dobpdc) (dobpdc 4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) that feature step-shaped CO 2 adsorption isotherms resulting from cooperative and reversible insertion of CO 2 into metal-amine bonds to form ammonium carbamate chains. Small modifications to the diamine structure are found to shift the threshold pressure for cooperative CO 2 adsorption by over 4 orders of magnitude at a given temperature, and the observed trends are rationalized on the basis of crystal structures of the isostructural zinc frameworks obtained from in situ single-crystal X-ray diffraction experiments. The structure-activity relationships derived from these results can be leveraged to tailor adsorbents to the conditions of a given CO 2 separation process. The unparalleled versatility of these materials, coupled with their high CO 2 capacities and low projected energy costs, highlights their potential as next-generation adsorbents for a wide array of CO 2 separations.

  20. Highly CO2-Tolerant Cathode for Intermediate-Temperature Solid Oxide Fuel Cells: Samarium-Doped Ceria-Protected SrCo0.85Ta0.15O3-δ Hybrid.

    Science.gov (United States)

    Li, Mengran; Zhou, Wei; Zhu, Zhonghua

    2017-01-25

    Susceptibility to CO2 is one of the major challenges for the long-term stability of the alkaline-earth-containing cathodes for intermediate-temperature solid oxide fuel cells. To alleviate the adverse effects from CO2, we incorporated samarium-stabilized ceria (SDC) into a SrCo0.85Ta0.15O3-δ (SCT15) cathode by either mechanical mixing or a wet impregnation method and evaluated their cathode performance stability in the presence of a gas mixture of 10% CO2, 21% O2, and 69% N2. We observed that the CO2 tolerance of the hybrid cathode outperforms the pure SCT15 cathode by over 5 times at 550 °C. This significant enhancement is likely attributable to the low CO2 adsorption and reactivity of the SDC protective layer, which are demonstrated through thermogravimetric analysis, energy-dispersive spectroscopy, and electrical conductivity study.