WorldWideScience

Sample records for ni yoru co2

  1. CO2 activation on bimetallic CuNi nanoparticles

    Directory of Open Access Journals (Sweden)

    Natalie Austin

    2016-10-01

    Full Text Available Density functional theory calculations have been performed to investigate the structural, electronic, and CO2 adsorption properties of 55-atom bimetallic CuNi nanoparticles (NPs in core-shell and decorated architectures, as well as of their monometallic counterparts. Our results revealed that with respect to the monometallic Cu55 and Ni55 parents, the formation of decorated Cu12Ni43 and core-shell Cu42Ni13 are energetically favorable. We found that CO2 chemisorbs on monometallic Ni55, core-shell Cu13Ni42, and decorated Cu12Ni43 and Cu43Ni12, whereas, it physisorbs on monometallic Cu55 and core-shell Cu42Ni13. The presence of surface Ni on the NPs is key in strongly adsorbing and activating the CO2 molecule (linear to bent transition and elongation of C˭O bonds. This activation occurs through a charge transfer from the NPs to the CO2 molecule, where the local metal d-orbital density localization on surface Ni plays a pivotal role. This work identifies insightful structure-property relationships for CO2 activation and highlights the importance of keeping a balance between NP stability and CO2 adsorption behavior in designing catalytic bimetallic NPs that activate CO2.

  2. Is NiCo2S4 really a semiconductor?

    KAUST Repository

    Xia, Chuan

    2015-08-31

    NiCo2S4 is a technologically important electrode material that has recently achieved remarkable performance in pseu-docapacitor, catalysis, and dye-synthesized solar cell applications.[1-5] Essentially, all reports on this material have pre-sumed it to be semiconducting, like many of the chalcogenides, with a reported band-gap in the range of 1.2-1.7 eV.[6,7] In this report, we have conducted detailed experimental and theoretical studies, most of which done for the first time, which overwhelmingly show that NiCo2S4 is in fact a metal. We have also calculated the Raman spectrum of this mate-rial and experimentally verified it for the first time, hence clarifying inconsistent Raman spectra reports. Some of the key results that support our conclusions include: (1) the measured carrier density in NiCo2S4 is 3.18×1022 cm-3, (2) Ni-Co2S4 has a room temperature resistivity of around 103 µΩ cm which increases with temperature, (3) NiCo2S4 exhibits a quadratic dependence of the magnetoresistance on magnetic field, (4) thermopower measurements show an extremely low Seebeck coefficient of 5 µV K-1, (5) first principles calculations confirm that NiCo2S4 is a metal. These results sug-gest that it is time to re-think the presumed semiconducting nature of this promising material. They also suggest that the metallic conductivity is another reason (besides the known significant redox activity) behind the excellent perfor-mance reported for this material.

  3. NiCo2O4-Based Supercapacitor Nanomaterials

    Science.gov (United States)

    Wang, Chenggang; Zhou, E; He, Weidong; Deng, Xiaolong; Huang, Jinzhao; Ding, Meng; Wei, Xianqi; Liu, Xiaojing; Xu, Xijin

    2017-01-01

    In recent years, the research on supercapacitors has ushered in an explosive growth, which mainly focuses on seeking nano-/micro-materials with high energy and power densities. Herein, this review will be arranged from three aspects. We will summarize the controllable architectures of spinel NiCo2O4 fabricated by various approaches. Then, we introduce their performances as supercapacitors due to their excellent electrochemical performance, including superior electronic conductivity and electrochemical activity, together with the low cost and environmental friendliness. Finally, the review will be concluded with the perspectives on the future development of spinel NiCo2O4 utilized as the supercapacitor electrodes. PMID:28336875

  4. Syngas Production from CO2 Reforming and CO2-steam Reforming of Methane over Ni/Ce-SBA-15 Catalyst

    Science.gov (United States)

    Tan, J. S.; Danh, H. T.; Singh, S.; Truong, Q. D.; Setiabudi, H. D.; Vo, D.-V. N.

    2017-06-01

    This study compares the catalytic performance of mesoporous 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane reactions in syngas production. The catalytic performance of 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane was evaluated in a temperature-controlled tubular fixed-bed reactor at stoichiometric feed composition, 1023 K and atmospheric pressure for 12 h on-stream with gas hourly space velocity (GHSV) of 36 L gcat -1 h-1. The 10 Ni/Ce-SBA-15 catalyst possessed a high specific BET surface area and average pore volume of 595.04 m2 g-1. The XRD measurement revealed the presence of NiO phase with crystallite dimension of about 13.60 nm whilst H2-TPR result indicates that NiO phase was completely reduced to metallic Ni0 phase at temperature beyond 800 K and the reduction temperature relied on different degrees of metal-support interaction associated with the location and size of NiO particles. The catalytic reactivity was significantly enhanced with increasing H2O/CO2 feed ratio. Interestingly, the H2/CO ratio for CO2-steam reforming of methane varied between 1 and 3 indicated the occurrence of parallel reactions, i.e., CH4 steam reforming giving a H2/CO of 3 whilst reverse water-gas shift (RWGS) reaction consuming H2 to produce CO gaseous product.

  5. Synthesis and catalytic activity of electrospun NiO/NiCo2O4 nanotubes for CO and acetaldehyde oxidation

    Science.gov (United States)

    Kim, Il Hee; Lee, Hyerim; Yu, Areum; Jeong, Jae Hwan; Lee, Youngmi; Kim, Myung Hwa; Lee, Chongmok; Dok Kim, Young

    2018-04-01

    NiO/NiCo2O4 nanotubes with a diameter of approximately 100 nm are synthesized using Ni and Co precursors via electro-spinning and subsequent calcination processes. The tubular structure is confirmed via transmission electron microscopy imaging, whereas the structures and elemental compositions of the nanotubes are determined using x-ray diffraction, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. N2 adsorption isotherm data reveal that the surface of the nanotubes consists of micropores, thereby resulting in a significantly higher surface area (˜20 m2 g-1) than expected for a flat-surface structure (present a study of the catalytic activity of our novel NiO/NiCo2O4 nanotubes for CO and acetaldehyde oxidation. The catalytic activity of NiO/NiCo2O4 is superior to Pt below 100 °C for CO oxidation. For acetaldehyde oxidation, the total oxidation activity of NiO/NiCo2O4 for acetaldehyde is comparable with that of Pt. Coexistence of many under-coordinated Co and Ni active sites in our structure is suggested be related to the high catalytic activity. It is suggested that our novel NiO/NiCo2O4 tubular structures with surface microporosity can be of interest for a variety of applications, including the catalytic oxidation of harmful gases.

  6. Hierarchically porous Ni monolith@branch-structured NiCo2O4 for high energy density supercapacitors

    Directory of Open Access Journals (Sweden)

    Mengjie Xu

    2016-06-01

    Full Text Available A variety of NiCo2O4 nanostrucutures ranging from nanowire to nanoplate and branched structures were successfully prepared via a simple hydrothermal process. The experimental results show that NiCo2O4 with branched structures possesses the best overall electrochemical performance. The improvement of energy density was explored in terms of hierarchically three-dimensional (3D metal substrates and a high specific area capacitance, and area energy density is obtained with hierarchically porous Ni monolith synthesized through a controlled combustion procedure.

  7. Heteromorphic NiCo2S4/Ni3S2/Ni Foam as a Self-Standing Electrode for Hydrogen Evolution Reaction in Alkaline Solution.

    Science.gov (United States)

    Liu, Hui; Ma, Xiao; Rao, Yuan; Liu, Yang; Liu, Jialiang; Wang, Luyang; Wu, Mingbo

    2018-04-04

    Considerable works have been devoted on developing high-efficiency nonplatinum electrocatalysts for hydrogen evolution reaction (HER). Herein, 3D heteromorphic NiCo 2 S 4 /Ni 3 S 2 nanosheets network has been constructed on Ni foam (denoted as NiCo 2 S 4 /Ni 3 S 2 /NF) serving as a self-standing electrocatalyst through directly thermal sulfurization of a single-source NiCo-layered double hydroxide precursor. The resultant NiCo 2 S 4 /Ni 3 S 2 /NF electrode exhibits outstanding electrocatalytic HER performance with an extremely low onset overpotential of 15 mV and long-term durability in alkaline solution. Such enhanced HER performance can be credited to (1) the massive exposed active sites provided by mixed transition metal chalcogenides (NiCo 2 S 4 and Ni 3 S 2 ), (2) the strong interfacial interaction at NiCo 2 S 4 /Ni 3 S 2 heterojunction interfaces with the strengthened H binding, and (3) the porous highly conductive Ni foam substrate with accelerated electron transfer. This work opens up a new direction to fabricate effective and non-noble-metal electrodes for water splitting and hydrogen generation.

  8. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    OpenAIRE

    Mengnan eWang; Jiaguang eZhang; Ning eYan

    2013-01-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active t...

  9. Carbon Deposition during CO2 Electrolysis in Ni-Based Solid-Oxide-Cell Electrodes

    DEFF Research Database (Denmark)

    Skafte, Theis Løye; Graves, Christopher R.; Blennow, P.

    2015-01-01

    -stabilized zirconia (Ni-YSZ) cermets were supplied by Haldor Topsoe A/S and the operating conditions were chosen so as to take stack relevant considerations into account. Formation of carbon nanotubes in Ni containing fuel electrodes has previously been observed in co-electrolysis of H2O and CO2 [1]. Hence....... Electrochemical impedance spectroscopy in both H2/H2O and CO/CO2 revealed an increase in resistance of the fuel electrode after each CO2 electrolysis current-voltage curve, indicating possible carbon deposition. The difference in partial oxygen pressure between inlet and outlet was analyzed to verify carbon...... in detail. In an attempt to mitigate the degradation due to carbon deposition, the Ni-YSZ electrode was infiltrated with a gadolinium doped ceria (CGO) solution. Initial results indicate that the coking tolerance was not enhanced, but it is still unclear whether infiltrated cells degrade less. However...

  10. Magnetic studies of Co2+, Ni2+, and Zn2+-modified DNA double-crossover lattices

    Science.gov (United States)

    Dugasani, Sreekantha Reddy; Oh, Young Hoon; Gnapareddy, Bramaramba; Park, Tuson; Kang, Won Nam; Park, Sung Ha

    2018-01-01

    We fabricated divalent-metal-ion-modified DNA double-crossover (DX) lattices on a glass substrate and studied their magnetic characteristics as a function of ion concentrations [Co2+], [Ni2+] and [Zn2+]. Up to certain critical concentrations, the DNA DX lattices with ions revealed discrete S-shaped hysteresis, i.e. characteristics of strong ferromagnetism, with significant changes in the coercive field, remanent magnetization, and susceptibility. Induced magnetic dipoles formed by metal ions in DNA duplex in the presence of a magnetic field imparted ferromagnetic behaviour. By considering hysteresis and the magnitude of magnetization in a magnetization-magnetic field curve, Co2+-modified DNA DX lattices showed a relatively strong ferromagnetic nature with an increasing (decreasing) trend of coercive field and remanent magnetization when [Co2+] ≤ 1 mM ([Co2+] > 1 mM). In contrast, Ni2+ and Zn2+-modified DNA DX lattices exhibited strong and weak ferromagnetic behaviours at lower (≤1 mM for Ni2+ and ≤0.5 mM for Zn2+) and higher (>1 mM for Ni2+ and >0.5 mM for Zn2+) concentrations of ions, respectively. About 1 mM of [Co2+], [Ni2+] and [Zn2+] in DNA DX lattices was of special interest with regard to physical characteristics and was identified to be an optimum concentration of each ion. Finally, we measured the temperature-dependent magnetic characteristics of the metal-ion-modified DNA DX lattices. Nonzero magnetization and inverse susceptibility with almost constant values were observed between 25 and 300 K, with no indication of a magnetic transition. This indicated that the magnetic Curie temperatures of Co2+, Ni2+ and Zn2+-modified DNA DX lattices were above 300 K.

  11. Catalytic hydrogenation of CO2 over Pt- and Ni-doped graphene: A comparative DFT study.

    Science.gov (United States)

    Esrafili, Mehdi D; Sharifi, Fahimeh; Dinparast, Leila

    2017-10-01

    Today, the global greenhouse effect of carbon dioxide (CO 2 ) is a serious environmental problem. Therefore, developing efficient methods for CO 2 capturing and conversion to valuable chemicals is a great challenge. The aim of the present study is to investigate the catalytic activity of Pt- or Ni-doped graphene for the hydrogenation of CO 2 by a hydrogen molecule. To gain a deeper insight into the catalytic mechanism of this reaction, the reliable density functional theory calculations are performed. The adsorption energies, geometric parameters, reaction barriers, and thermodynamic properties are calculated using the M06-2X density functional. Two reaction mechanisms are proposed for the hydrogenation of CO 2 . In the bimolecular mechanism, the reaction proceeds in two steps, initiating by the co-adsorption of CO 2 and H 2 molecules over the surface, followed by the formation of a OCOH intermediate by the transfer of H atom of H 2 toward O atom of CO 2 . In the next step, formic acid is produced as a favorable product with the formation of CH bond. In our proposed termolecular mechanism, however, H 2 molecule is directly activated by the two pre-adsorbed CO 2 molecules. The predicted activation energy for the formation of the OCOH intermediate in the bimolecular mechanism is 20.8 and 47.9kcalmol -1 over Pt- and Ni-doped graphene, respectively. On the contrary, the formation of the first formic acid in the termolecular mechanism is found as the rate-determining step over these surfaces, with an activation energy of 28.8 and 45.5kcal/mol. Our findings demonstrate that compared to the Ni-doped graphene, the Pt-doped surface has a relatively higher catalytic activity towards the CO 2 reduction. These theoretical results could be useful in practical applications for removal and transformation of CO 2 to value-added chemical products. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. CO2 capture in Mg oxides doped with Fe and Ni

    International Nuclear Information System (INIS)

    Sanchez S, I. F.

    2016-01-01

    In this work the CO 2 capture-desorption characteristics in Mg oxides doped with Fe and Ni obtained by the direct oxidation of Mg-Ni and Mg-Fe mixtures are presented. Mixtures of Mg-Ni and Mg-Fe in a different composition were obtained by mechanical milling in a Spex-type mill in a controlled atmosphere of ultra high purity argon at a weight / weight ratio of 4:1 powder using methanol as a lubricating agent, for 20 h. The powders obtained by mechanical milling showed as main phase, the Mg with nanocrystalline structure. Subsequently, the mixtures of Mg-Ni and Mg-Fe were oxidized within a muffle for 10 min at 600 degrees Celsius. By means of X-ray diffraction analysis, the Mg O with nano metric grain size was identified as the main phase, which was determined by the Scherrer equation. In the Mg O doped with Ni, was identified that as the Ni amount 1 to 5% by weight dispersed in the Mg O matrix was increased, the main peak intensity of the Ni phase increased, whereas in the Mg O doped with Fe was observed by XRD, that the Fe 2 O 3 phase was present and by increasing the amount of Fe (1 to 5% by weight) dispersed in the crystalline phase of Mg O, the intensity of this impurity also increased. Sem-EDS analysis showed that the Ni and Fe particles are dispersed homogeneously in the Mg O matrix, and the particles are porous, forming agglomerates. Through energy dispersive spectroscopy analysis, the elemental chemical composition obtained is very close to the theoretical composition. The capture of CO 2 in the Mg O-1% Ni was carried out in a Parr reactor at different conditions of pressure, temperature and reaction time. Was determined that under the pressure of 0.2 MPa at 26 degrees Celsius for 1 h of reaction, the highest CO 2 capture of 7.04% by weight was obtained, while in Mg O-1% Fe the CO 2 capture was 6.32% by weight. The other magnesium oxides doped in 2.5 and 5% by weight Ni and Fe showed lower CO 2 capture. The different stages of mass loss and thermal

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

    Science.gov (United States)

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

    2018-03-01

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

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

    Science.gov (United States)

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

    2018-04-01

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

  15. Facile synthesis of NiCo2O4@Polyaniline core-shell nanocomposite for sensitive determination of glucose.

    Science.gov (United States)

    Yu, Zhiyuan; Li, Hejun; Zhang, Xinmeng; Liu, Ningkun; Tan, Wenlong; Zhang, Xu; Zhang, Leilei

    2016-01-15

    In this work, the core-shell structure of NiCo2O4@Polyaniline (NiCo2O4@PANI) nanocomposite is fabricated via a facile hydrothermal treatment followed by a post-Polyaniline (PANI) coating process. The synthesized materials are characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectrometer. The biosensing properties of NiCo2O4@PANI composite and NiCo2O4 nanoparticles toward glucose are studied based on glassy carbon electrode. Electrochemical studies indicate that the obtained core-shell NiCo2O4@PANI composite shows higher electrocatalytic activity toward the oxidation of glucose, compared with NiCo2O4 nanoparticles. The enhanced performance is related to the core-shell structure of NiCo2O4@PANI composite and the outstanding conductivity of the polyaniline shell. At a potential of +0.5V, the NiCo2O4@PANI nanocomposite modified glass carbon electrode demonstrates a wide linear range up to 4.7350mM with sensitivity of 4.55mAmM(-1)cm(-2) and detection limit of 0.3833μM. It also shows significant electrochemical stability, good reproducibility and excellent selectivity. The results suggest that the NiCo2O4@PANI nanocomposite is a promising electrode material for electrochemical biosensor. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Synthesis and analysis of Fe 3, Co 2 and Ni 2: PEO+ PVP blended ...

    Indian Academy of Sciences (India)

    Blended polymer films of polyethylene oxide + polyvinyl pyrrolidone (PEO + PVP) containing transition metal (TM) ions like Fe3+, Co2+ and Ni2+ have been synthesized by a solution casting method. For these films, structural, thermal, magnetic and optical properties have been studied. X-ray diffraction results reveal the ...

  17. Atomically dispersed Ni(i) as the active site for electrochemical CO2 reduction

    Science.gov (United States)

    Yang, Hong Bin; Hung, Sung-Fu; Liu, Song; Yuan, Kaidi; Miao, Shu; Zhang, Liping; Huang, Xiang; Wang, Hsin-Yi; Cai, Weizheng; Chen, Rong; Gao, Jiajian; Yang, Xiaofeng; Chen, Wei; Huang, Yanqiang; Chen, Hao Ming; Li, Chang Ming; Zhang, Tao; Liu, Bin

    2018-02-01

    Electrochemical reduction of CO2 to chemical fuel offers a promising strategy for managing the global carbon balance, but presents challenges for chemistry due to the lack of effective electrocatalyst. Here we report atomically dispersed nickel on nitrogenated graphene as an efficient and durable electrocatalyst for CO2 reduction. Based on operando X-ray absorption and photoelectron spectroscopy measurements, the monovalent Ni(i) atomic center with a d9 electronic configuration was identified as the catalytically active site. The single-Ni-atom catalyst exhibits high intrinsic CO2 reduction activity, reaching a specific current of 350 A gcatalyst-1 and turnover frequency of 14,800 h-1 at a mild overpotential of 0.61 V for CO conversion with 97% Faradaic efficiency. The catalyst maintained 98% of its initial activity after 100 h of continuous reaction at CO formation current densities as high as 22 mA cm-2.

  18. Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst

    Science.gov (United States)

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-01-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability. PMID:24790945

  19. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    Science.gov (United States)

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-09-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  20. Transformation of sodium bicarbonate and CO2 into sodium formate over NiPd nanoparticle catalyst.

    Science.gov (United States)

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-01-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  1. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    Directory of Open Access Journals (Sweden)

    Mengnan eWang

    2013-09-01

    Full Text Available The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs. Ni NPs and eight NiM (M stands for a second metal NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  2. Flexible Asymmetric Threadlike Supercapacitors Based on NiCo2Se4Nanosheet and NiCo2O4/Polypyrrole Electrodes.

    Science.gov (United States)

    Wang, Qiufan; Ma, Yun; Wu, Yunlong; Zhang, Daohong; Miao, Menghe

    2017-04-10

    Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo 2 Se 4 positive electrode and a NiCo 2 O 4 @PPy (PPy: polypyrrole) negative electrode. The as-prepared electrodes display outstanding volume specific capacitance (14.2 F cm -3 ) and excellent cycling performance (94 % retention after 5000 cycles at 0.6 mA) owing to their nanosheet and nanosphere structures. The asymmetric all-solid-state threadlike supercapacitor expanded the stability voltage window from 0-1.0 V to 0-1.7 V and exhibits high volume energy density (5.18 mWh cm -3 ) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Facile synthesis of hierarchically mesoporous NiCo2O4 nanowires for sensitive nonenzymatic glucose detection

    Science.gov (United States)

    Qin, Zhenhua; Cheng, Qunpeng; Lu, Yao; Li, Jianfen

    2017-07-01

    Glucose nonenzymatic detection is of significance in the fields of biological, environmental, food monitoring, and clinical analysis. By employing mesoporous NiCo2O4 nanowires as electrochemical sensor, highly sensitive nonenzymatic detection of glucose has been realized. The NiCo2O4 nanowires were synthesized via a facile hydrothermal method and subsequent thermal treatment. Their crystalline structures were analyzed by X-ray diffraction, and morphologies were characterized using scanning electron microscopy and transmission electron microscopy. The porous characteristics and real surface areas of the synthesized NiCo2O4 were studied by Brunauer-Emmett-Teller method. Electro-catalytic oxidation of glucose on the NiCo2O4 electrode was investigated by cyclic voltammetry, linear sweep voltammetry, and amperometry. The nonenzymatic sensor based on NiCo2O4 exhibited superior performance for glucose detection, with a low detection limit and excellent sensitivity.

  4. Does terrestrial drought explain global CO2 flux anomalies induced by El Niño?

    Directory of Open Access Journals (Sweden)

    G. J. Collatz

    2011-09-01

    Full Text Available The El Niño Southern Oscillation is the dominant year-to-year mode of global climate variability. El Niño effects on terrestrial carbon cycling are mediated by associated climate anomalies, primarily drought, influencing fire emissions and biotic net ecosystem exchange (NEE. Here we evaluate whether El Niño produces a consistent response from the global carbon cycle. We apply a novel bottom-up approach to estimating global NEE anomalies based on FLUXNET data using land cover maps and weather reanalysis. We analyze 13 years (1997–2009 of globally gridded observational NEE anomalies derived from eddy covariance flux data, remotely-sensed fire emissions at the monthly time step, and NEE estimated from an atmospheric transport inversion. We evaluate the overall consistency of biospheric response to El Niño and, more generally, the link between global CO2 flux anomalies and El Niño-induced drought. Our findings, which are robust relative to uncertainty in both methods and time-lags in response, indicate that each event has a different spatial signature with only limited spatial coherence in Amazônia, Australia and southern Africa. For most regions, the sign of response changed across El Niño events. Biotic NEE anomalies, across 5 El Niño events, ranged from –1.34 to +0.98 Pg C yr−1, whereas fire emissions anomalies were generally smaller in magnitude (ranging from –0.49 to +0.53 Pg C yr−1. Overall drought does not appear to impose consistent terrestrial CO2 flux anomalies during El Niños, finding large variation in globally integrated responses from –1.15 to +0.49 Pg C yr−1. Despite the significant correlation between the CO2 flux and El Niño indices, we find that El Niño events have, when globally integrated, both enhanced and weakened terrestrial sink strength, with no consistent response across events.

  5. Hydrogenation of heteroaromatics by high pressure DTA techniques. 3; Koatsu DTA ho ni yoru hokozoku kagobutsu no suisoka (rutenium tanji shokubai ni yoru kakusuisoka datsu hetero hanno)

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, M.; Yoshida, T. [Hokkaido National Industrial Research Institute, Sapporo (Japan); Kotanigawa, T. [Japan International Cooperation Agency, Tokyo (Japan)

    1996-10-28

    Ring-opening of heteroaromatics and heteroatom-removal reaction were studied experimentally using the acidic catalyst containing phosphoric acid for improvement of an upgrading method of coal derived oils. In experiment, some Ru-carrying metal oxide catalysts such as RMZ, RML and RMN catalyst, and MNP catalyst containing phosphoric acid were used as specimens. Nuclear hydrogenation reaction and hydro-denitrogenation reaction of dibenzothiophene and carbazole were compared with each other. The experimental results are as follows. Both RMN and RMNP catalysts offer a superior selectivity in nuclear hydrogenation reaction and hydro-denitrogenation reaction of carbazole. Although both catalysts offer an extremely high nuclear hydrogenation activity at 360{degree}C, these offer the high selectivity of denitrogenation products at 430{degree}C. In comparison of the activities of MN and MNP catalysts with the same Mn2O3:NiO ratio, MNP catalyst offers the higher denitrogenation activity than MN catalyst at 430{degree}C. 1 ref., 3 tabs.

  6. NiCo2S4nanosheet-decorated 3D, porous Ni film@Ni wire electrode materials for all solid-state asymmetric supercapacitor applications.

    Science.gov (United States)

    Saravanakumar, Balasubramaniam; Jayaseelan, Santhana Sivabalan; Seo, Min-Kang; Kim, Hak-Yong; Kim, Byoung-Suhk

    2017-12-07

    Wire type supercapacitors with high energy and power densities have generated considerable interest in wearable applications. Herein, we report a novel NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode for high performance supercapacitor application. In this work, a facile method is introduced to fabricate a 3D, porous Ni film deposited on a Ni wire as a flexible electrode, followed by decoration with NiCo 2 S 4 as an electroactive material. The fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode displays a superior performance with an areal and volumetric capacitance of 1.228 F cm -2 and 199.74 F cm -3 , respectively, at a current density of 0.2 mA cm -1 with a maximum volumetric energy and power density (E V : 6.935 mW h cm -3 ; P V : 1.019 W cm -3 ). Finally, the solid state asymmetric wire type supercapacitor is fabricated using the fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire as a positive electrode and N-doped reduced graphene oxide (N-rGO) as a negative electrode and this exhibits good areal and volumetric capacitances of C A : 0.12 F cm -2 and C V : 19.57 F cm -2 with a higher rate capability (92%). This asymmetric wire type supercapacitor demonstrates a low leakage current and self-discharge with a maximum volumetric energy (E V : 5.33 mW h cm -3 ) and power (P V : 855.69 mW cm -3 ) density.

  7. Three-dimensional electrode of Ni/Co layered double hydroxides@NiCo2S4@graphene@Ni foam for supercapacitors with outstanding electrochemical performance

    International Nuclear Information System (INIS)

    Tao, Yan; Ruiyi, Li; Lin, Zhou; Chenyang, Ma; Zaijun, Li

    2015-01-01

    We reported a new strategy for fabricating three-dimensiona electrode of Ni/Co layered double hydroxide@NiCo 2 S 4 @graphene@Ni foam for supercapacitors. The resulting 3D electrode offers a jungle-like architecture. The unique structure creates ultra fast electron transfer and electrolyte transport as well as the maximum utilization rate of the space and the surface. The electrode exhibits a prominent advantage of high specific capacitance, high-current capacitive behaviour and cycle stability. - Highlights: • The study developed a new strategy for fabricating 3D electrode of Ni/Co-LDH@NiCo 2 S 4 @G. • The as-prepared 3D electrode offers a jungle-like architecture. • The unique structure creates an efficient conduction network and high mass loading. • The electrode achieves significantly synergetic effect among different materials. • The electrode exhibits an excellent electrochemical performance for supercapacitors. - ABSTRACT: Great challenge for the fabrication of free-standing three-dimensional electrode still remains to simultaneously achieve high specific capacitance, rate performance and cycle stability. The paper reprted a new three-dimensional (3D) electrode of Ni/Co layered double hydroxide@NiCo 2 S 4 @graphene@Ni foam (Ni/Co-LDH@NiCo 2 S 4 @G) for supercapacitors. The as-prepared 3D electrode offers an unique architecture, which create an efficient conduction network and maximum utilization of space and interface. The graphene acts as well-knit and conductive skin coated on the skeleton of Ni foam for growing NiCo 2 S 4 . The conductive NiCo 2 S 4 array serves as bridge between Ni/Co-LDH and graphene, leading to ultrafast electron transfer and electrolyte transport. A slew of splits and holes existing in the NiCo 2 S 4 array play one role as the ion-reservoir to contain host of electrolyte ions. To evaluate the feasibility of 3D electrode’s application in supercapacitors, the electrochemical performance was investigated by using the three

  8. Mo2NiB2-type Sm2Co2Al and Sm2Co2Ga compounds: Magnetic properties and giant low-temperature coercivity

    Science.gov (United States)

    Morozkin, A. V.; Garshev, A. V.; Yapaskurt, V. O.; Yao, Jinlei; Nirmala, R.; Quezado, S.; Malik, S. K.

    2018-04-01

    The magnetic ordering of Mo2NiB2-type Sm2Co2Al and Sm2Co2Ga (Immm, No. 71, oI10) compounds has been established using bulk magnetic measurements. Polycrystalline Sm2Co2Al and Sm2Co2Ga undergo ferromagnetic transitions (TC) at 50 K and 62 K, respectively, and low-temperature field induced transitions (Tm) around 14 K and 16 K (in a field of 10 kOe), respectively. Between TC and Tm Sm2Co2Al and Sm2Co2Ga are soft ferromagnets. Below Tm Sm2Co2Al and Sm2Co2Ga exhibit permanent magnet properties with a residual magnetization per samarium of 0.38 μB and 0.36 μB, respectively, and a large coercive field of 69 kOe and 72 kOe, respectively, at 5 K. The magnetocaloric effects of Sm2Co2Al and Sm2Co2Ga were calculated in terms of isothermal magnetic entropy change and they reach maximum values of -1.62 J/kg K and -1.31 J/kg K for a field change of 50 kOe at 50 K and 58 K, respectively. Low temperature magnetic ordering with enhanced anisotropy in Sm2Co2Al and Sm2Co2Ga is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +1.63 J/kg K and +1.06 J/kg K for a field change of 50 kOe at 10 K and 8 K, respectively. The magnetocaloric effects of Sm2Co2Al and Sm2Co2Ga were calculated in terms of isothermal magnetic entropy change and they reach maximum values of -1.62 J/kg K and -1.31 J/kg K for a field change of 50 kOe at 50 K and 58 K, respectively. Low temperature magnetic ordering with enhanced anisotropic effects in Sm2Co2Al and Sm2Co2Ga is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +1.63 J/kg K and +1.06 J/kg K for a field change of 50 kOe at 10 K and 8 K, respectively.

  9. Oxygen electrode bifunctional electrocatalyst NiCo2O4 spinel

    Science.gov (United States)

    Fielder, William L.; Singer, Joseph

    1988-01-01

    A significant increase in energy density may be possible if a two-unit alkaline regenerative H2-O2 fuel cell is replaced with a single-unit system that uses passive means for H2O transfer and thermal control. For this single-unit system, new electrocatalysts for the O2 electrode will be required which are not only bifunctionally active but also chemically and electrochemically stable between the voltage range of about 0.7 and 1.5 V. NiCo2O4 spinel is reported to have certain characteristics that make it useful for a study of electrode fabrication techniques. High surface area NiCo2O4 powder was fabricated into unsupported, bifunctional, PTFE-bonded, porous gas fuel cell electrodes by commercial sources using varying PTFE contents and sintering temperatures. The object of this study is to measure the bifunctional activities of these electrodes and to observe what performance differences might result from different commercial electrode fabricators. O2 evolution and O2 reduction data were obtained at 80 C (31 percent KOH). An irreversible reaction (i.e., aging) occurred during O2 evolution at potentials greater than about 1.5 V. Anodic Tafel slopes of 0.06 and 0.12 V/decade were obtained for the aged electrodes. Within the range of 15 to 25 percent, the PTFE content was not a critical parameter for optimizing the electrode for O2 evolution activity. Sintering temperatures between 300 and 340 C may be adequate but heating at 275 C may not be sufficient to properly sinter the PTFE-NiCo2O4 mixture. Electrode disintegration was observed during O2 reduction. Transport of O2 to the NiCo2O4 surface became prohibitive at greater than about -0.02 A/sq cm. Cathodic Tafel slopes of -0.6 and -0.12 V/decade were assumed for the O2 reduction process. A PTFE content of 25 percent (or greater) appears to be preferable for sintering the PTFE-NiCo2O4 mixture.

  10. Effects of Co2O3 on electromagnetic properties of NiCuZn ferrites

    Science.gov (United States)

    Yan, Shuoqing; Liu, Sheng; He, Jun; Luo, Heng; He, Longhui; Li, Yuhan; Huang, Shengxiang; Deng, Lianwen

    2018-04-01

    The effects of Co2O3 addition on the electromagnetic properties of NiCuZn ferrite were investigated, by considering the variation of complex permeability, complex permittivity and quasi-microwave absorption property in the 1-1000 MHz frequency range. Results show that the introduction of Co3+ ions in NiCuZn ferrite leads to the marked shifting of magnetic resonance towards high-frequency and a slight increase of the permittivity. These Co-related effects enhance the maximum reflection loss in NiCuZn ferrite to reach -55.1 dB with its absorption bandwidth being tunable in the frequency range 480-1000 MHz, which provides a potential absorber for the anti-electromagnetic interference applications in electronic industry.

  11. Nickel Nanowire@Porous NiCo2O4 Nanorods Arrays Grown on Nickel Foam as Efficient Pseudocapacitor Electrode

    Directory of Open Access Journals (Sweden)

    Houzhao Wan

    2017-12-01

    Full Text Available A three dimensional hierarchical nanostructure composed of nickel nanowires and porous NiCo2O4 nanorods arrays on the surface of nickel foam is successfully fabricated by a facile route. In this structure, the nickel nanowires are used as core materials to support high-pseudocapacitance NiCo2O4 nanorods and construct the well-defined NiCo2O4 nanorods shell/nickel nanowires core hierarchical structure on nickel foam. Benefiting from the participation of nickel nanowires, the nickel nanowire@NiCo2O4/Ni foam electrode shows a high areal specific capacitance (7.4 F cm−2 at 5 mA cm−2, excellent rate capability (88.04% retained at 100 mA cm−2, and good cycling stability (74.08% retained after 1,500 cycles. The superior electrochemical properties made it promising as electrode for supercapacitors.

  12. NiCo2S4 nanowires array as an efficient bifunctional electrocatalyst for full water splitting with superior activity

    Science.gov (United States)

    Liu, Danni; Lu, Qun; Luo, Yonglan; Sun, Xuping; Asiri, Abdullah M.

    2015-09-01

    The present communication reports the topotactic conversion of NiCo2O4 nanowires array on carbon cloth (NiCo2O4 NA/CC) into NiCo2S4 NA/CC, which is used as an efficient bifunctional electrocatalyst for water splitting with good durability and superior activity in 1.0 M KOH. This NiCo2S4 NA/CC electrode produces 100 mA cm-2 at an overpotential of 305 mV for hydrogen evolution and 100 mA cm-2 at an overpotential of 340 mV for oxygen evolution. To afford a 10 mA cm-2 water-splitting current, the alkaline water electrolyzer made from NiCo2S4 NA/CC needs a cell voltage of 1.68 V, which is 300 mV less than that for NiCo2O4 NA/CC, and has good stability.The present communication reports the topotactic conversion of NiCo2O4 nanowires array on carbon cloth (NiCo2O4 NA/CC) into NiCo2S4 NA/CC, which is used as an efficient bifunctional electrocatalyst for water splitting with good durability and superior activity in 1.0 M KOH. This NiCo2S4 NA/CC electrode produces 100 mA cm-2 at an overpotential of 305 mV for hydrogen evolution and 100 mA cm-2 at an overpotential of 340 mV for oxygen evolution. To afford a 10 mA cm-2 water-splitting current, the alkaline water electrolyzer made from NiCo2S4 NA/CC needs a cell voltage of 1.68 V, which is 300 mV less than that for NiCo2O4 NA/CC, and has good stability. Electronic supplementary information (ESI) available: Experimental section and ESI Figures. See DOI: 10.1039/c5nr04064g

  13. Recent Scientific Progress on Developing Supported Ni Catalysts for Dry (CO2 Reforming of Methane

    Directory of Open Access Journals (Sweden)

    Hyun Ook Seo

    2018-03-01

    Full Text Available Two major green house gases (CO2 and CH4 can be converted into useful synthetic gas (H2 and CO during dry reforming of methane (DRM reaction, and a lot of scientific efforts has been made to develop efficient catalysts for dry reforming of methane (DRM. Noble metal-based catalysts can effectively assist DRM reaction, however they are not economically viable. Alternatively, non-noble based catalysts have been studied so far, and supported Ni catalysts have been considered as a promising candidate for DRM catalyst. Main drawback of Ni catalysts is its catalytic instability under operating conditions of DRM (>700 °C. Recently, it has been demonstrated that the appropriate choice of metal-oxide supports can address this issue since the chemical and physical of metal-oxide supports can prevent coke formation and stabilize the small Ni nanoparticles under harsh conditions of DRM operation. This mini-review covers the recent scientific findings on the development of supported Ni catalysts for DRM reaction, including the synthetic methods of supported Ni nanoparticles with high sintering resistance.

  14. Efficient sulfur host based on NiCo2O4 hollow microtubes for advanced Li-S batteries

    Science.gov (United States)

    Iqbal, Azhar; Ali Ghazi, Zahid; Muqsit Khattak, Abdul; Ahmad, Aziz

    2017-12-01

    High energy density and cost effectiveness make lithium-sulfur battery a promising candidate for next-generation electrochemical energy storage technology. Here, we have synthesized a highly efficient sulfur host namely NiCo2O4 hollow microtubes/sulfur composite (NiCo2O4/S). The hollow interior cavity providing structural integrity while sufficient self-functionalized surfaces of NiCo2O4 chemically bind polysulfides to prevent their dissolution in the organic electrolyte. When used in lithium-sulfur batteries, the synthesized NiCo2O4/S cathode delivers high specific capacity (1274 mAh g-1 at 0.2 C), long cycling performance at 0.5 C, and good rate capability at high current rates.

  15. Closed Pore Structured NiCo2O4-Coated Nickel Foams for Stable and Effective Oil/Water Separation.

    Science.gov (United States)

    Li, Yan; Zheng, Xi; Yan, Zhanheng; Tian, Dongliang; Ma, Jianmin; Zhang, Xiaofang; Jiang, Lei

    2017-08-30

    To solve the serious problem caused by oily wastewater pollution, unique interface designs, for example, membranes with superwetting properties such as superhydrophobicity/superoleophilicity and superhydrophilicity/underwater superoleophobicity, provide a good way to achieve oil/water separation. Here, inspired by the liquid storage property of the honeycomb structure, we propose a strategy to fabricate NiCo 2 O 4 -coated nickel foams for stable and efficient oil/water separation. NiCo 2 O 4 with a closed-pore structure was formed by assembling nanoflakes with a micro/nanoscale hierarchical structure. Compared with nickel foam coated by NiCo 2 O 4 with an open-pore structure (NiCo 2 O 4 nanowires), the enclosed nanostructure of NiCo 2 O 4 nanoflakes can firmly hold water for a more stable superhydrophilic/underwater superoleophobic interface. As a consequence, the NiCo 2 O 4 -nanoflake-coated nickel foam has a larger oil breakthrough pressure than the NiCo 2 O 4 -nanowire-coated nickel foam because of a slightly larger oil advancing angle and a lower underwater oil adhesion force, which makes it more stable and efficient for oil/water separation. Moreover, the NiCo 2 O 4 -coated nickel foams have excellent chemical and mechanical stability, and they are reusable for oil-water separation. This work will be beneficial for the design and development of stable underwater superoleophobic self-cleaning materials and related device applications, such as oil/water separation.

  16. Carbon Supported Engineering NiCo2O4 Hybrid Nanofibers with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

    Science.gov (United States)

    Hassan, Diab; El-safty, Sherif; Khalil, Khalil Abdelrazek; Dewidar, Montasser; Abu El-magd, Gamal

    2016-01-01

    The design of cheap and efficient oxygen reduction reaction (ORR) electrocatalysts is of a significant importance in sustainable and renewable energy technologies. Therefore, ORR catalysts with superb electrocatalytic activity and durability are becoming a necessity but still remain challenging. Herein, we report C/NiCo2O4 nanocomposite fibers fabricated by a straightforward electrospinning technique followed by a simple sintering process as a promising ORR electrocatalyst in alkaline condition. The mixed-valence oxide can offer numerous accessible active sites. In addition, the as-obtained C/NiCo2O4 hybrid reveals significantly remarkable electrocatalytic performance with a highly positive onset potential of 0.65 V, which is only 50 mV lower than that of commercially available Pt/C catalysts. The analyses indicate that C/NiCo2O4 catalyst can catalyze O2-molecules via direct four electron pathway in a similar behavior as commercial Pt/C catalysts dose. Compared to single NiCo2O4 and carbon free NiCo2O4, the C/NiCo2O4 hybrid displays higher ORR current and more positive half-wave potential. The incorporated carbon matrices are beneficial for fast electron transfer and can significantly impose an outstanding contribution to the electrocatalytic activity. Results indicate that the synthetic strategy hold a potential as efficient route to fabricate highly active nanostructures for practical use in energy technologies. PMID:28773878

  17. Carbon Supported Engineering NiCo2O4 Hybrid Nanofibers with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Diab Hassan

    2016-09-01

    Full Text Available The design of cheap and efficient oxygen reduction reaction (ORR electrocatalysts is of a significant importance in sustainable and renewable energy technologies. Therefore, ORR catalysts with superb electrocatalytic activity and durability are becoming a necessity but still remain challenging. Herein, we report C/NiCo2O4 nanocomposite fibers fabricated by a straightforward electrospinning technique followed by a simple sintering process as a promising ORR electrocatalyst in alkaline condition. The mixed-valence oxide can offer numerous accessible active sites. In addition, the as-obtained C/NiCo2O4 hybrid reveals significantly remarkable electrocatalytic performance with a highly positive onset potential of 0.65 V, which is only 50 mV lower than that of commercially available Pt/C catalysts. The analyses indicate that C/NiCo2O4 catalyst can catalyze O2-molecules via direct four electron pathway in a similar behavior as commercial Pt/C catalysts dose. Compared to single NiCo2O4 and carbon free NiCo2O4, the C/NiCo2O4 hybrid displays higher ORR current and more positive half-wave potential. The incorporated carbon matrices are beneficial for fast electron transfer and can significantly impose an outstanding contribution to the electrocatalytic activity. Results indicate that the synthetic strategy hold a potential as efficient route to fabricate highly active nanostructures for practical use in energy technologies.

  18. Novel Catalytic Process for SNG Synthesis; Sesshokuho ni yoru atarashii daitai tennen gasu no seizo koutei

    Energy Technology Data Exchange (ETDEWEB)

    Ninomiya, Akira.; Sato, Misuzu.; Ishihara, Tatsumi.; Takita, Yusaku. [Oita University, Oita (Japan). Faculty of Engineering; Murata, Toshio. [Nippon Bunri University, Oita (Japan). Faculty of Engiineering

    1999-04-10

    Methane rich city gas has been synthesized by means of steam reforming of naphtha; houever, the produced gas always contains significant concentration of CO{sub 2}. Therefore, development of a methane production process containing no CO and CO{sub 2} removal processes is strongly requested. Authors reported in the previous paper that C{sub 3}H{sub 8}{yields}2CH{sub 4}+C(1) took place over Ni/SiO{sub 2} with 90% selectivity. In this paper, the catalyst supports were studied and found that neutral SiO{sub 2} and {alpha}-Al{sub 2}O{sub 3} are suitable but the activity was much reduced over Ni supported siO{sub 2}-Al{sub 2}O{sub 3}. Catalyst was diluted by various materials to avoid blocking-up by deposited carbon. Several diluted materials affected the convesion. {alpha}-Al{sub 2}O{sub 3} and basic MgO accelerated the reaction which may be to interaction between Ni and dilution materials with direct contact. Over Ni/SiO{sub 2}, reaction (1) took place with 90% selectivity, so that the produced gas always contained H{sub 2} formed by the C{sub 3}H{sub 8}{yields}3C+4H{sub 2} (2). It has confirmed that H{sub 2} in a high concentration of CH{sub 4} can be reacted with C{sub 3}H{sub 8} to produce CH{sub 4}. From these results,a following simple synthesis process can v/be constituted; the first step is CH{sub 4}, H{sub 2}, and solid C formation from C{sub 3}H{sub 8}, and the second step is succeeding H{sub 2} consumption process of the produced gas in the first step. (author)

  19. Self-template synthesis of yolk-shelled NiCo2O4 spheres for enhanced hybrid supercapacitors

    Science.gov (United States)

    Wang, Liang; Jiao, Xinyan; Liu, Peng; Ouyang, Yu; Xia, Xifeng; Lei, Wu; Hao, Qingli

    2018-01-01

    A self-template method is developed for hierarchically yolk-shelled NiCo2O4 spheres (YS-NiCo2O4) through a controlled hydrolysis process and followed by a thermal annealing treatment. The yolk-shelled NiCo2O4 spheres possess out-shell consisting of hundreds of ultrathin sheets with 3-5 nm in thickness and solid yolk composing of a large number of nanoparticles. The YS-NiCo2O4 generates a large specific surface area of 169.6 m2 g-1. Benefit from the large specific surface area and rich oxygen vacancy, the as-fabricated YS-NiCo2O4 as electrode materials for supercapacitor exhibits high specific capacitance of 835.7 F g-1 at 0.5 A g-1, an enhanced rate capability and excellent electrochemical stability with 93% retention after 10,000 cycles even at 10 A g-1. Moreover, a hybrid supercapacitor combined with YS-NiCo2O4 and graphene shows a high energy density of 34.7 Wh kg-1 at the power density of 395.0 W kg-1 at 0.5 A g-1, even at 20 A g-1, the hybrid supercapacitor still delivers the energy density of about 12.1 Wh kg-1 and the power density of 11697 W kg-1. The desirable performance of yolk-shelled NiCo2O4 suggests it to be a promising material as supercapacitor electrodes.

  20. Ni Nanoparticles Supported on Cage-Type Mesoporous Silica for CO2 Hydrogenation with High CH4 Selectivity.

    Science.gov (United States)

    Budi, Canggih Setya; Wu, Hung-Chi; Chen, Ching-Shiun; Saikia, Diganta; Kao, Hsien-Ming

    2016-09-08

    Ni nanoparticles (around 4 nm diameter) were successfully supported on cage-type mesoporous silica SBA-16 (denoted as Ni@SBA-16) via wet impregnation at pH 9, followed by the calcination-reduction process. The Ni@SBA-16 catalyst with a very high Ni loading amount (22.9 wt %) exhibited exceptionally high CH4 selectivity for CO2 hydrogenation. At a nearly identical loading amount, the Ni@SBA-16 catalysts with smaller particle size of Ni NPs surprisingly exhibited a higher catalytic activity of CO2 hydrogenation and also led to a higher selectivity on CH4 formation than the Ni@SiO2 catalysts. This enhanced activity of the Ni@SBA-16 catalyst is suggested to be an accumulative result of the advantageous structural properties of the support SBA-16 and the well confined Ni NPs within the support; both induced a favorable reaction pathway for high selectivity of CH4 in CO2 hydrogenation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Depolymerization of coal by oxidation and alkylation; Sanka bunkai to alkyl ka ni yoru sekitan kaijugo

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, H.; Isoda, T.; Kusakabe, K.; Morooka, S. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hayashi, J. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

    1996-10-28

    Change in depolymerization degree and coal structure was studied for depolymerization treatment of coal in various alcohol containing aqueous hydrogen peroxide. In experiment, the mixture of Yallourn coal, alcohol and aqueous hydrogen peroxide was agitated in nitrogen atmosphere of normal pressure at 70{degree}C for 12 hours. As the experimental result, the methanol solubility of only 5% of raw coal increased up to 35.2% by hydrogen peroxide treatment, while the yield of insoluble matters also decreased from 94% to 62%. Most of the gas produced during treatment was composed of inorganic gases such as CO and CO2, and its carbon loss was extremely decreased by adding alcohol. From the analytical result of carbon loss in hydrogen peroxide treatment, it was clarified that alkylation advances with introduction of alkyl group derived from alcohol into coal by hydrogen peroxide treatment under a coexistence of alcohol, and depolymerization reaction of coal itself is thus promoted by alcohol. 4 refs., 7 figs., 1 tab.

  2. Synthesis and characterization of NiCo2O4 nanoplates as efficient electrode materials for electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Kim, Taehyun; Ramadoss, Ananthakumar; Saravanakumar, Balasubramaniam; Veerasubramani, Ganesh Kumar; Kim, Sang Jae

    2016-01-01

    Highlights: • NiCo 2 O 4 nanoplates were synthesized through a facile approach. • The NiCo 2 O 4 nanoplates electrode material exhibit a specific capacitance of 332 F g −1 at 5 mV s −1 . • The fabricated NiCo 2 O 4 electrode reveals 86% retention of initial capacitance after 2000 cycles. - Abstract: In the present work, NiCo 2 O 4 nanoplates were prepared by a facile, low temperature, hydrothermal method, followed by thermal annealing and used supercapacitor applications. The physico-chemical characterization of as-prepared materials were investigated by means of X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM). The electrochemical measurements demonstrate that the NiCo 2 O 4 nanoplates electrode (NC-5) exhibits a high specific capacitance of 332 F g −1 at a scan rate of 5 mV s −1 and also retained about 86% of the initial specific capacitance value even after 2000 cycles at a current density of 2.5 A g −1 . These results suggest that the fabricated electrode material has huge potential as a novel electrode material for electrochemical capacitors.

  3. Comment on Qian et al. 2008: La Niña and El Niño composites of atmospheric CO2 change

    Directory of Open Access Journals (Sweden)

    Andrew M. Chiodi

    2014-02-01

    Full Text Available It is well known that interannual extremes in the rate of change of atmospheric CO2 are strongly influenced by the occurrence of El Niño-Southern Oscillation (ENSO events. Qian et al. presented ENSO composites of atmospheric CO2 changes. We show that their composites do not reflect the atmospheric changes that are most relevant to understanding the role of ENSO on atmospheric CO2 variability. We present here composites of atmospheric CO2 change that differ markedly from those of Qian et al., and reveal previously unreported asymmetries between the effects on the global carbon system of El Niño and La Niña events. The calendar-year timing differs; La Niña changes in atmospheric CO2 typically occur primarily over September–May, while El Niño changes occur primarily over December–August. And the net concentration change is quite different; La Niña changes are about half the size of El Niño changes. These results illustrate new aspects of the ENSO/global carbon budget interaction and provide useful global-scale benchmarks for the evaluation of Earth System Model studies of the carbon system.

  4. A two-step hydrothermal synthesis approach to synthesize NiCo2S4/NiS hollow nanospheres for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Xu, Rui; Lin, Jianming; Wu, Jihuai; Huang, Miaoliang; Fan, Leqing; He, Xin; Wang, Yiting; Xu, Zedong

    2017-11-01

    In this work, a high-performance asymmetric supercapacitor device based on NiCo2S4/NiS hollow nanospheres as the positive electrode and the porous activated carbon as the negative electrode was successfully fabricated via a facile two-step hydrothermal synthesis approach. This NiCo2S4/NiS//activated carbon asymmetric supercapacitor achieved a high energy density of 43.7 Wh kg-1 at a power density of 160 W kg-1, an encouraging specific capacitance of 123 F g-1 at a current density of 1 mA cm-2, as well as a long-term performance with capacitance degradation of 5.2% after 3000 consecutive cycles at 1 mA cm-2. Moreover, the NiCo2S4/NiS electrode also demonstrated an excellent specific capacitance (1947.5 F g-1 at 3 mA cm-2) and an outstanding cycling stability (retaining 90.3% after 1000 cycles). The remarkable electrochemical performances may be attributed to the effect of NiS doping on NiCo2S4 which could enlarge the surface area and increase the surface roughness.

  5. A Study of CO2 Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics

    Directory of Open Access Journals (Sweden)

    Yanyan Feng

    2015-01-01

    Full Text Available This work studied the influence of textural characteristics of CNTs on catalytic performance of Ni/CNTs for CO2 methanation. The CNTs supports were prepared by chemical vapor deposition method using Ni/MgO catalysts, and acetonitrile and ethanol were used as carbon sources, respectively. The Ni/CNTs catalysts were prepared via impregnation method and characterized by X-ray diffraction (XRD, N2 adsorption/desorption, and temperature-programmed reduction (H2-TPR techniques. The results indicated that the textural characteristics of CNTs supports significantly impacted on the catalytic performance of Ni/CNTs. The catalyst Ni/CNTs-E (CNTs using ethanol as carbon source had good reducibility, high specific surface area, and moderate defects, resulting in higher CO2 conversion and CH4 yield, followed by Ni/CNTs-C (commercial CNTs and Ni/CNTs-A (CNTs using acetonitrile as carbon source. Based on Arrhenius formula, activation energies of the catalysts were calculated and were found decreased for Ni/CNTs-A and Ni/CNTs-E.

  6. In Situ Exsolution of Bimetallic Rh-Ni Nanoalloys: a Highly Efficient Catalyst for CO2Methanation.

    Science.gov (United States)

    Arandiyan, Hamidreza; Wang, Yuan; Scott, Jason; Mesgari, Sara; Dai, Hongxing; Amal, Rose

    2018-03-22

    Unique CO 2 methanation catalysts comprising bimetallic Ni-Rh nanoalloy/3DOM LaAlO 3 have been successfully prepared via a poly(methyl methacrylate) microsphere colloidal crystal-templating route, followed by the in situ growth of Ni nanoparticles (NPs). Here, we show that unlike traditional Ni particles deposited on a perovskite support, the exsolution of Ni occurs on both the external and internal surface of the porous perovskite substrate, leading to a strong metal-support interaction. Owing to the exsolution of Ni and the formation of Ni-Rh nanoalloys, a 52% enhancement in the methanation turnover frequency was obtained over the Ni-Rh/3DOM LaAlO 3 [13.9 mol/(mol h)] compared to Rh/3DOM LaNi 0.08 Al 0.92 O 3 [9.16 mol/(mol h)] before reduction treatment. The results show that the low-temperature reducibility, rich surface adsorbed oxygen species, and basic sites of the catalyst greatly improve its activity toward CO 2 methanation. The hierarchically porous structure of the perovskite support provides a high dispersion of bimetallic Ni-Rh NPs.

  7. Magnetoresistance in Co/2D MoS2/Co and Ni/2D MoS2/Ni junctions.

    Science.gov (United States)

    Zhang, Han; Ye, Meng; Wang, Yangyang; Quhe, Ruge; Pan, Yuanyuan; Guo, Ying; Song, Zhigang; Yang, Jinbo; Guo, Wanlin; Lu, Jing

    2016-06-28

    Semiconducting single-layer (SL) and few-layer MoS2 have a flat surface, free of dangling bonds. Using density functional theory coupled with non-equilibrium Green's function method, we investigate the spin-polarized transport properties of Co/2D MoS2/Co and Ni/2D MoS2/Ni junctions with MoS2 layer numbers of N = 1, 3, and 5. Well-defined interfaces are formed between MoS2 and metal electrodes. The junctions with a SL MoS2 spacer are almost metallic owing to the strong coupling between MoS2 and the ferromagnets, while those are tunneling with a few layer MoS2 spacer. Both large magnetoresistance and tunneling magnetoresistance are found when fcc or hcp Co is used as an electrode. Therefore, flat single- and few-layer MoS2 can serve as an effective nonmagnetic spacer in a magnetoresistance or tunneling magnetoresistance device with a well-defined interface.

  8. NiCo2S4@NiMoO4 Core-Shell Heterostructure Nanotube Arrays Grown on Ni Foam as a Binder-Free Electrode Displayed High Electrochemical Performance with High Capacity

    Science.gov (United States)

    Zhang, Yan; Xu, Jie; Zheng, Yayun; Zhang, Yingjiu; Hu, Xing; Xu, Tingting

    2017-06-01

    Core-shell-structured system has been proved as one of the best architecture for clean energy products owing to its inherited superiorities from both the core and the shell part, which can provide better conductivity and high surface area. Herein, a hierarchical core-shell NiCo2S4@NiMoO4 heterostructure nanotube array on Ni foam (NF) (NiCo2S4@NiMoO4/NF) has been successfully fabricated. Because of its novel heterostructure, the capacitive performance has been enhanced. A specific capacitance up to 2006 F g-1 was obtained at a current density of 5 mA cm-2, which was far higher than that of pristine NiCo2S4 nanotube arrays (about 1264 F g-1). More importantly, NiCo2S4@NiMoO4/NF and active carbon (AC) were congregated as positive electrode and negative electrode in an asymmetric supercapacitor. As-fabricated NiCo2S4@NiMoO4/NF//AC device has a good cyclic behavior with 78% capacitance retention over 2000 cycles, and exhibits a high energy density of 21.4 Wh kg-1 and power density of 58 W kg-1 at 2 mA cm-2. As displayed, the NiCo2S4@NiMoO4/NF core-shell herterostructure holds great promise for supercapacitors in energy storage.

  9. Study of highly efficient power generation system based on chemical-looping combustion; Chemical loop nenshoho ni yoru kokoritsu hatsuden system no kaihatsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, S.; Suzuki, T.; Yamamoto, M. [Tokyo Institute of Technology, Tokyo (Japan). Research Laboratory of Resources Utilization

    1997-02-01

    This paper describes the research and development of power generation system by means of chemical-looping combustion. For this system, fuel flows in a reduction reactor and air flows in an oxidation reactor. These two flows are separated. As a result, recovery of CO2 without energy consumption, drastic improvement of power generation efficiency, and suppression of NOx emission are expected. To realize the above, two promising candidates, NiCoO2/YSZ and NiO2/NiAl2O4, have been found as recycle solid particles between the both reactors. These have excellent oxidation/reduction cycle characteristics. By these particles as well as the existing particle, NiO/YSZ, practical application of the chemical-looping combustion is realized. Besides LNG, coal and hydrogen were considered as fuels. When using coal or hydrogen, it was found that temperature of the reduction reactor should be increased the same as that of the oxidation reactor. This is a different point from a case using LNG as a fuel. 5 refs., 2 figs.

  10. Three-dimensional hierarchical NiCo2O4 nanowire@Ni3S2 nanosheet core/shell arrays for flexible asymmetric supercapacitors

    Science.gov (United States)

    Liu, Bo; Kong, Dezhi; Huang, Zhi Xiang; Mo, Runwei; Wang, Ye; Han, Zhaojun; Cheng, Chuanwei; Yang, Hui Ying

    2016-05-01

    Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power density of 56.33 W cm-3 at 0.94 mW h cm-3. As a result, the hybrid nanoarchitecture opens a new way to design high performance electrodes for electrochemical energy storage applications.Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power

  11. 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

  12. Mesoporous NiCo2O4 nano-needles supported by 3D interconnected carbon network on Ni foam for electrochemical energy storage

    Science.gov (United States)

    Lu, Congxiang; Liu, Wen-wen; Pan, Hui; Tay, Beng Kang; Wang, Xingli; Liang, Kun; Wei, Xuezhe

    2018-05-01

    In this work, a three dimensional (3D) interconnected carbon network consisting of ultrathin graphite (UG) and carbon nanotubes (CNTs) on Ni foam is fabricated and employed as a novel type of substrate for mesoporous NiCo2O4 nano-needles. The successfully synthesized NiCo2O4 nano-needles/CNTs/UG on Ni foam has many advantages including facile electrolyte access and direct conducting pathways towards current collectors, which enable it to be a promising electrode material in battery-like electrochemical energy storage. Encouragingly, a high capacity of 135.1 mAh/g at the current density of 1 A/g, superior rate performance and also stable cycling for 1200 cycles at the current density of 5 A/g have been demonstrated in this novel material.

  13. Fabrication of porous nanosheets assembled from NiCo2O4/NiO electrode for electrochemical energy storage application.

    Science.gov (United States)

    Wei, Chao; Huang, Ying; Chen, Menghua; Yan, Jing; Yao, Wen; Chen, Xuefang

    2017-10-15

    In this work, The NiCo 2 O 4 /NiO electrode materials are successfully synthesized via hydrothermal and following calcination approach. Due to the distinctive porous nanosheets assembled structure through controlling effectively the feeding amount of HMT, the NiCo 2 O 4 /NiO electrode possesses excellent specific surface area and reasonable pore size distribution, which hence minimizes the intrinsic electrode resistance and improves the morphology and structure stability. Therefore, the NiCo 2 O 4 /NiO electrode delivers a superior specific capacitance (Csp) (992.85Fg -1 at the current density of 1Ag -1 ), good rate capability (79.14% Csp retention even at 10Ag -1 ) and considerable cycle life (79.82% Csp retention at 10Ag -1 after 5000 times). Furthermore, the asymmetric supercapacitor is successfully assembled by NCN-0.1 as positive electrode and activated carbon (AC) as negative electrode. The NCN-0.1//AC device delivers a relatively excellent energy density of 47.43kWkg -1 at a power density of 0.389Whkg -1 . Consequently, the outstanding performance and stability of the ASC device shows great potential for future energy storage application. Copyright © 2017. Published by Elsevier Inc.

  14. 3-D honeycomb NiCo2S4 with high electrochemical performance used for supercapacitor electrodes

    Science.gov (United States)

    Zhang, Zhiguo; Huang, Xiao; Li, Huan; Zhao, Yingyuan; Ma, Tingli

    2017-04-01

    A new nanostructured 3-D honeycomb NiCo2S4 (NC-1) has been successfully prepared by a simple hydrothermal method assisted sulfuration procedure. The morphology of the 3-D honeycomb was investigated by FESEM and TEM, and the results suggest the NC-1 has a highly porous structure. Its chemical composition was characterized by XRD and XPS and the results indicate that the NC-1 is the pure phase of NiCo2S4. In order to study the effect of morphology on the electrochemical performance, we have also prepared needle-, flake- and petal-like nanostructured NiCo2S4 on Ni foam. When they were used as supercapacitor electrodes, the NC-1 exhibited the highest electrochemical performance among these four kinds of electrodes. Its maximum specific capacity was over 14 mAh cm-2 at 1 mA m-2 and it still yielded 7.96 mAh cm-2 even at 50 mA cm-2. The NC-1 remained 99.64% of the initial capacity after the long-term test of 1000 cycles. Consequently, the NC-1 has the promising potential as an energy storage system in the future and it can also be used as an ideal substrate for other active materials involving a faradaic process.

  15. Spinel FeCo2S4 nanoflower arrays grown on Ni foam as novel binder-free electrodes for long-cycle-life supercapacitors

    Science.gov (United States)

    Deng, Cuifen; Yang, Lishan; Yang, Chunming; Shen, Ping; Zhao, Liping; Wang, Zhiyu; Wang, Chunhui; Li, Junhua; Qian, Dong

    2018-01-01

    Spinel FeCo2S4 nanoflower arrays grown on Ni foam (FeCo2S4@Ni) have been successfully fabricated via a facile hydrothermal sulfurization of the corresponding FeCo2O4 precursor. The results of X-ray diffraction and X-ray photoelectron spectroscopy characterizations affirm that partial Co2+/Co3+ ions in Co3S4 have been substituted by Fe2+/Fe3+ ions to form FeCo2S4. The obtained FeCo2S4@Ni exhibits an ultrahigh specific capacitance (1644.07 mF cm-2 at 50 mA cm-2) and a supreme cycling stability (∼100% after 10,000 cycles at 50 mA cm-2) as binder-free electrodes for supercapacitors. The cycling stability of the fabricated product is the highest among the documented ternary metallic sulfides so far. The excellent supercapacitive performance of FeCo2S4@Ni emanates from the unique architectures of Fe2Co2S4 nanoflower arrays constituted by ultrathin nanoflakes, three-dimensional porous and conductive Ni foam, and solid skeleton of Ni foam for robust connections to the Fe2Co2S4.

  16. Production of high-strength Al85Y8Ni5Co2 bulk alloy by spark plasma sintering

    International Nuclear Information System (INIS)

    Surreddi, K B; Scudino, S; Sakaliyska, M; Eckert, J; Srivastava, V C; Uhlenwinkel, V; Kim, J S

    2010-01-01

    Highly dense bulk samples were produced by spark plasma sintering (SPS) through combined devitrification and consolidation of partially amorphous Al 85 Y 8 Ni 5 Co 2 gas atomized powders. The microstructure of the consolidated samples shows a mixed structure containing crystalline, ultrafine-grained and amorphous/nanocrystalline particles. The sintered sample exhibits a remarkable high strength of about 1050 MPa combined with 3.7 % fracture strain.

  17. Synthesis of reticulated hollow spheres structure NiCo2S4 and its application in organophosphate pesticides biosensor.

    Science.gov (United States)

    Peng, Lei; Dong, Sheying; Wei, Wenbo; Yuan, Xiaojing; Huang, Tinglin

    2017-06-15

    Electrode materials play a key role in the development of electrochemical sensors, particularly enzyme-based biosensors. Here, a novel NiCo 2 S 4 with reticulated hollow spheres assembled from rod-like structures was prepared by a one-pot solvothermal method and its formation mechanism was discussed. Moreover, comparison of NiCo 2 S 4 materials from different experiment conditions as biosensors was investigated by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), and the best one that was reticulated hollow spheres assembled from rod-like structures NiCo 2 S 4 has been successfully employed as a matrix of AChE immobilization for the special structure, superior conductivity and rich reaction active sites. When using common two kinds of organophosphate pesticides (OPs) as model analyte, the biosensors demonstrated a wide linear range of 1.0×10 -12 -1.0×10 -8 gmL -1 with the detection limit of 4.2×10 -13 gmL -1 for methyl parathion, and 1.0×10 -13 -1.0×10 -10 gmL -1 with the detection limit of 3.5×10 -14 gmL -1 for paraoxon, respectively. The proposed biosensors exhibited many advantages such as acceptable stability and low cost, providing a promising tool for analysis of OPs. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. How easy is CO2 fixation by M-C bond containing complexes (M = Cu, Ni, Co, Rh, Ir)?

    KAUST Repository

    Nolan, Steve

    2015-11-27

    A comparison between different M–C bonds (M = Cu(I), Ni(II), Co(I), Rh(I) and Ir(I)) has been reported by using density functional theory (DFT) calculations to explore the role of the metal in the fixation or incorporation of CO2 into such complexes. The systems investigated are various metal based congeners of the Ir-complex 8 [(cod)(IiPr)Ir-CCPh], with a ligand scaffold based on cod and IiPr ligands (cod = 1,5-cyclooctadiene; IiPr = 1,3-bis(isopropyl)imidazol-2-ylidene). The results of this study show that the calculated CO2 insertion barriers follow the trend: Cu(I) (20.8 kcal mol−1) < Rh(I) (30.0 kcal mol−1) < Co(I) (31.3 kcal mol−1) < Ir(I) (37.5 kcal mol−1) < Ni(II) (45.4 kcal mol−1), indicating that the Cu(I) based analogue is the best CO2 fixer, while Ni(II) is the worst in the studied series.

  19. Highly stable ceria-zirconia-yttria supported Ni catalysts for syngas production by CO2 reforming of methane

    Science.gov (United States)

    Muñoz, M. A.; Calvino, J. J.; Rodríguez-Izquierdo, J. M.; Blanco, G.; Arias, D. C.; Pérez-Omil, J. A.; Hernández-Garrido, J. C.; González-Leal, J. M.; Cauqui, M. A.; Yeste, M. P.

    2017-12-01

    Ni/CeO2/YSZ and Ni/Ce0.15Zr0.85O2 have been investigated as catalysts for the dry reforming of methane at 750 °C. Ni was incorporated by the impregnation method. The supports were previously activated by using a thermo-chemical protocol consisting on a severe reduction (H2/Ar) at 950 °C followed by a mild oxidation (O2/He) at 500 °C. According to TPR results, this protocol leads to the development of unique redox properties in the case of the CeO2/YSZ oxide. Two types of CO2 + CH4 (1:1) mixtures (helium-diluted and undiluted) were used to feed the reactor. When using the Ni/Ce0.15Zr0.85O2 catalyst with undiluted feed, the reactor became plugged by coke. By contrast, Ni/CeO2/YSZ behaved as an active and stable catalyst even under the most severe operation conditions. The characterization of the spent Ni/CeO2/YSZ using TGA, TEM, Raman and XPS spectroscopy revealed that only a limited amount of graphitic carbon, in form of nanotubes, was formed. No evidences of deactivating carbonaceous forms were obtained. The singular redox properties of the activated CeO2/YSZ oxides are proposed as a key for designing Ni catalysts highly stable in reforming processes.

  20. 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.

  1. Nanostructural origin of semiconductivity and large magnetoresistance in epitaxial NiCo2O4/Al2O3 thin films

    Science.gov (United States)

    Zhen, Congmian; Zhang, XiaoZhe; Wei, Wengang; Guo, Wenzhe; Pant, Ankit; Xu, Xiaoshan; Shen, Jian; Ma, Li; Hou, Denglu

    2018-04-01

    Despite low resistivity (~1 mΩ cm), metallic electrical transport has not been commonly observed in inverse spinel NiCo2O4, except in certain epitaxial thin films. Previous studies have stressed the effect of valence mixing and the degree of spinel inversion on the electrical conduction of NiCo2O4 films. In this work, we studied the effect of nanostructural disorder by comparing the NiCo2O4 epitaxial films grown on MgAl2O4 (1 1 1) and on Al2O3 (0 0 1) substrates. Although the optimal growth conditions are similar for the NiCo2O4 (1 1 1)/MgAl2O4 (1 1 1) and the NiCo2O4 (1 1 1)/Al2O3 (0 0 1) films, they show metallic and semiconducting electrical transport, respectively. Post-growth annealing decreases the resistivity of NiCo2O4 (1 1 1)/Al2O3 (0 0 1) films, but the annealed films are still semiconducting. While the semiconductivity and the large magnetoresistance in NiCo2O4 (1 1 1)/Al2O3 (0 0 1) films cannot be accounted for in terms of non-optimal valence mixing and spinel inversion, the presence of anti-phase boundaries between nano-sized crystallites, generated by the structural mismatch between NiCo2O4 and Al2O3, may explain all the experimental observations in this work. These results reveal nanostructural disorder as being another key factor for controlling the electrical transport of NiCo2O4, with potentially large magnetoresistance for spintronics applications.

  2. Modeling of Gas Diffusion in Ni/YSZ Electrodes in CO2 and Co-electrolysis

    DEFF Research Database (Denmark)

    Duhn, Jakob Dragsbæk; Jensen, Anker Degn; Wedel, Stig

    2017-01-01

    to prevent its formation. For prediction of carbon formation, the gas composition in the electrode must be known. In this work, the diffusion of gases in the electrode has been modeled with the dusty gas model in 1 and 2 dimensions, and the effect of tortuosity, porosity, temperature, electrode thickness......Carbon formation may occur during CO2 and CO2/H2O electrolysis using solid oxide electrolyzer cells due to the Boudouard reaction (2CO →  CO2 + C(s)). Formed carbon may disintegrate the cell structure and it is therefore of importance to be able to predict when carbon is formed, and take actions......, pore diameter, current density, pitch and rib width has been investigated. It is shown that diffusion limitations on reactant/product transport may lead to carbon formation. The parameters describing the microstructure and the dimensions of the cathode channels and interconnect ribs are found to have...

  3. Study of the O2/CO2 combustion technology; Sanso nensho gijutsu ni kakawaru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kato, M. [Center for Coal Utilization, Japan, Tokyo (Japan); Kiga, T.; Yamada, T. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan); Arai, K. [Nippon Sanso K.K., Tokyo (Japan); Mori, T. [Inst. of Research and Innovation, Tokyo (Japan); Kimura, N.; Okawa, M. [Electric Power Development Co. Ltd., Tokyo (Japan)

    1996-09-01

    This study is being progressed during a period from 1992 to 1999 as part of the NEDO`s clean coal technology program. This paper describes what has been discussed to date. The absorption method and the adsorption method may be used to recover CO2 as means to deal with the problem of global warming resulted from burning coals. These methods, however, have problems in economy caused from concentration of CO2 in flue gas being low. The present study is intended to raise the CO2 concentration in flue gas by using oxygen plus circulated flue gas in the place of combustion air, so that CO2 may be recovered as it is without being separated from the flue gas. Therefore, an oxygen-blown pulverized coal fired power generation plant having a cryogenic oxygen manufacturing equipment was designed to discuss the plant operability and economy, and the pulverized coal combustion technology by using a dynamic simulation. A large number of findings have been obtained already, and the study has reached a level at which grasping the whole image is now possible. 13 figs.

  4. Kinetics for Steam and CO2 Reforming of Methane Over Ni/La/Al2O3 Catalyst.

    Science.gov (United States)

    Park, Myung Hee; Choi, Bong Kwan; Park, Yoon Hwa; Moon, Dong Ju; Park, Nam Cook; Kim, Young Chul

    2015-07-01

    Kinetic studies of mixed (steam and dry) reforming of methane on Ni/La/Al2O3 and Ni/La-Co (1, 3 wt%)/Al2O3 catalysts were performed in an atmospheric fixed-bed reactor. Kinetic parameters for the mixed reforming over these catalysts were obtained under reaction conditions free from heat and mass transfer limitations. Variables for the mixed reforming were the reaction temperature and partial pressure of reactants. The fitting of the experimental data for the rate of methane conversion, rCH4, using the power law rate equation rCH4 = k(PrCH4)α(PCO2)β(PH2O)γ showed that the reaction orders α, β, and γ are steady and obtained values equal to α = 1, β = 0, and γ = 0. In other words, among CH4, CO2, H2O, and H2, only CH4 reaction orders were not zero and they were affected by the promoters. The apparent activation energy on catalysts Ni/La/Al2O3, Ni/La-Co (1)/Al2O3 and Ni/La-Co (3)/Al2O3 is 85.2, 93.8, and 99.4 kJ/mol, respectively. The addition of Co to Ni/La/Al2O3 was increased the apparent activation energy of the mixed reforming reaction. And the Ni/La-Co (3 wt%)/Al2O3 catalyst showed the highest reforming activity and apparent activation energy. The Co promoters can increase the apparent activation energy of mixed reforming of methane.

  5. Economically synthesized NiCo2S4/reduced graphene oxide composite as efficient counter electrode in dye-sensitized solar cell

    Science.gov (United States)

    Nan, Hui; Han, Jianhua; Luo, Qiang; Yin, Xuewen; Zhou, Yu; Yao, Zhibo; Zhao, Xiaochong; Li, Xin; Lin, Hong

    2018-04-01

    Exploiting efficient Pt-free counter-electrode materials with low cost and highly catalytic property is a hot topic in the field of Dye-sensitized solar cells (DSCs). Here, NiCo2S4/reduced graphene oxide (RGO) was prepared via an economical synthesis route, and the as-prepared composite exhibited comparable electrocatalytic property with the conventional Pt electrode as the counter-electrode. Notably, the introduction of RGO into the NiCo2S4 counter-electrode induces a significantly promoted electrocatalytic rate towards the triiodide reduction than that of pristine NiCo2S4 by increasing surface area in the composite electrode, as revealed by electrochemical impedance spectroscopic measurement and Tafel polarization measurement. The easy synthesis, low cost and excellent electrochemical performance of the NiCo2S4/RGO composites enable themselves to serve as promising counter-electrode candidates for efficient DSCs.

  6. Carbon Deposition during CO2 Electrolysis in Ni-Based Solid-Oxide-Cell Electrodes

    DEFF Research Database (Denmark)

    Skafte, Theis Løye; Graves, Christopher R.; Blennow, P.

    2015-01-01

    threshold for carbon formation. The degradation observed was related to the fuel electrode, as confirmed by electrochemical impedance spectroscopy. Mitigation of the degradation mechanism was attempted by infiltrating gadolinium doped ceria. The onset of carbon deposition was largely unaffected......The carbon formation threshold in an operating cell was investigated during electrolysis of an idealized reactant atmosphere of CO and CO2. The electrolysis current was gradually increased in steps until the cell voltage spontaneously increased, thereby indicating cell degradation and possibly...... the onset of carbon deposition. The outlet gas composition at each current step was estimated based on the inlet gas composition and the reactant conversion using Faraday's law. The increase in voltage was observed at lower outlet pCO/pCO2 ratios than that corresponding to the expected thermodynamic...

  7. Electrodeposited binder-free NiCo2O4@carbon nanofiber as a high performance anode for lithium ion batteries

    Science.gov (United States)

    Zhang, Jie; Chu, Ruixia; Chen, Yanli; Jiang, Heng; Zhang, Ying; Huang, Nay Ming; Guo, Hang

    2018-03-01

    Binder-free nickel cobaltite on a carbon nanofiber (NiCo2O4@CNF) anode for lithium ion batteries was prepared via a two-step procedure of electrospinning and electrodeposition. The CNF was obtained by annealing electrospun poly-acrylonitrile (PAN) in nitrogen (N2). The NiCo2O4 nanostructures were then grown on the CNF by electrodeposition, followed by annealing in air. Experimental results showed that vertically aligned NiCo2O4 nanosheets had uniformly grown on the surface of the CNF, forming an interconnected network. The NiCo2O4@CNF possessed considerable lithium storage capacity and cycling stability. It exhibited a high reversible capacity of 778 mAhg-1 after 300 cycles at a current density of 0.25 C (1 C = 890 mAg-1) with an average capacity loss rate of 0.05% per cycle. The NiCo2O4@CNF had considerable rate capacities, delivering a capacity of 350 mAhg-1 at a current density of 2.0 C. The outstanding electrochemical performance can be mainly attributed to the following: (1) The nanoscale structure of NiCo2O4 could not only shorten the diffusion path of lithium ions and electrons but also increase the specific surface area, providing more active sites for electrochemical reactions. (2) The CNF with considerable mechanical strength and electrical conductivity could function as an anchor for the NiCo2O4 nanostructure and ensure an efficient electron transfer. (3) The porous structure resulted in a high specific surface area and an effective buffer for the volume changes during the repeated charge-discharge processes. Compared with a conventional hydrothermal method, electrodeposition could significantly simplify the preparation of NiCo2O4, with a shorter preparation period and lower energy consumption. This work provides an alternative strategy to obtain a high performance anode for lithium ion batteries.

  8. NiCo2O4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

    KAUST Repository

    Wang, Renqi

    2016-03-04

    Ternary transition metal oxides such as NiCo2O4 show great promise as supercapacitor electrode materials. However, the unsatisfactory rate performance of NiCo2O4 may prove to be a major hurdle to its commercial usage. Herein, we report the development of NiCo2O4@TiN core–shell nanostructures for all-solid-state supercapacitors with significantly enhanced rate capability. We demonstrate that a thin layer of TiN conformally grown by atomic layer deposition (ALD) on NiCo2O4 nanofiber arrays plays a key role in improving their electrical conductivity, mechanical stability, and rate performance. Fabricated using the hybrid NiCo2O4@TiN electrodes, the symmetric all-solid-state supercapacitor exhibited an impressive stack power density of 58.205 mW cm−3 at a stack energy density of 0.061 mWh cm−3. To the best of our knowledge, these values are the highest of any NiCo2O4-based all-solid-state supercapacitor reported. Additionally, the resulting NiCo2O4@TiN all-solid-state device displayed outstanding cycling stability by retaining 70% of its original capacitance after 20,000 cycles at a high current density of 10 mA cm−2. These results illustrate the promise of ALD-assisted hybrid NiCo2O4@TiN electrodes for sustainable and integrated energy storage applications.

  9. One-step hydrothermal synthesis of sandwich-type NiCo2S4@reduced graphene oxide composite as active electrode material for supercapacitors

    Science.gov (United States)

    Wang, Fangping; Li, Guifang; Zhou, Qianqian; Zheng, Jinfeng; Yang, Caixia; Wang, Qizhao

    2017-12-01

    A facile one step hydrothermal process is developed for the synthesis of NiCo2S4@reduced graphene oxide (NiCo2S4@RGO) composite as electrode for electrochemical supercapacitors. This NiCo2S4@RGO electrode exhibits an ultrahigh specific capacitance of 2003 F g-1 at 1 A g-1 and 1726 F g-1 at 20 A g-1 (86.0% capacitance retention from 1 A g-1 to 20 A g-1), excellent cycling stabilities (86.0% retention after 3500 cycles). Moreover, an asymmetric supercapacitor is successfully assembled by using NiCo2S4@RGO nanoparticle as the positive electrode and active carbon(AC) as the negative electrode in 2 M KOH electrolyte. The fabricated NiCo2S4@RGO//AC asymmetric supercapacitor exhibits a high energy density of 21.9 Wh kg-1 at a power density of 417.1 W kg-1 and still remains an impressive energy density of 13.5 Wh kg-1 at a large power density of 2700 W kg-1. The results demonstrate that the NiCo2S4@RGO composite is a promising electrode material as supercapacitors in energy storage.

  10. Multiscale Computational Study on the Adsorption and Separation of CO2 /CH4 and CO2 /H2 on Li+ -Doped Mixed-Ligand Metal-Organic Framework Zn2 (NDC)2 (diPyNI).

    Science.gov (United States)

    Sokhanvaran, Vahid; Yeganegi, Saeid

    2016-12-15

    The quantum mechanics (QM) method and grand canonical Monte Carlo (GCMC) simulations are used to study the effect of lithium cation doping on the adsorption and separation of CO 2 , CH 4 , and H 2 on a twofold interwoven metal-organic framework (MOF), Zn 2 (NDC) 2 (diPyNI) (NDC=2,6-naphthalenedicarboxylate; diPyNI=N,N'-di-(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide). Second-order Moller-Plesset (MP2) calculations on the (Li + -diPyNI) cluster model show that the energetically most favorable lithium binding site is above the pyridine ring side at a distance of 1.817 Å from the oxygen atom. The results reveal that the adsorption capacity of Zn 2 (NDC) 2 (diPyNI) for carbon dioxide is higher than those of hydrogen and methane at room temperature. Furthermore, GCMC simulations on the structures obtained from QM calculations predict that the Li + -doped MOF has higher adsorption capacities than the nondoped MOF, especially at low pressures. In addition, the probability density distribution plots reveal that CO 2 , CH 4 , and H 2 molecules accumulate close to the Li cation site. The selectivity results indicate that CO 2 /H 2 selectivity values in Zn 2 (NDC) 2 (diPyNI) are higher than those of CO 2 /CH 4 . The selectivity of CO 2 over CH 4 on Li + -doped Zn 2 (NDC) 2 (diPyNI) is improved relative to the nondoped MOF. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Application of Chemical Doping and Architectural Design Principles To Fabricate Nanowire Co2Ni3ZnO8 Arrays for Aqueous Asymmetric Supercapacitors.

    Science.gov (United States)

    Liu, Qi; Yang, Bin; Liu, Jingyuan; Yuan, Yi; Zhang, Hongsen; Liu, Lianhe; Wang, Jun; Li, Rumin

    2016-08-10

    Electrode materials derived from transition metal oxides have a serious problem of low electron transfer rate, which restricts their practical application. However, chemically doped graphene transforms the chemical bonding configuration to enhance electron transfer rate and, therefore, facilitates the successful fabrication of Co2Ni3ZnO8 nanowire arrays. In addition, the Co2Ni3ZnO8 electrode materials, considered as Ni and Zn ions doped into Co3O4, have a high electron transfer rate and electrochemical response capability, because the doping increases the degree of crystal defect and reaction of Co/Ni ions with the electrolyte. Hence, the Co2Ni3ZnO8 electrode exhibits a high rate property and excellent electrochemical cycle stability, as determined by electrochemical analysis of the relationship between specific capacitance, IR drop, Coulomb efficiency, and different current densities. From the results of a three-electrode system of electrochemical measurement, the Co2Ni3ZnO8 electrode demonstrates a specific capacitance of 1115 F g(-1) and retains 89.9% capacitance after 2000 cycles at a current density of 4 A g(-1). The energy density of the asymmetric supercapacitor (AC//Co2Ni3ZnO8) is 54.04 W h kg(-1) at the power density of 3200 W kg(-1).

  12. Oxidation Kinetics of Propane-Air Mixture over NiCo2O4 Catalyst Emitted from LPG Vehicles

    Directory of Open Access Journals (Sweden)

    Suverna Trivedi

    2017-05-01

    Full Text Available This paper describes the kinetics of catalytic air oxidation of propane. The kinetics data were collected in a plug flow tubular reactor. The experiments were performed over the NiCo2O4 catalyst prepared by co-precipitation method followed by calcination at 400 oC. The kinetic data were collected under the following conditions: 200 mg of catalyst, 2.5 % of propane in air, total flow rate of 60 mL/min, and temperature ranges of 130-170 oC. The data were fitted to the power law rate equation. The activation    energy and frequency factor were found to be 59.3 kJ/g mol and 2.9×108 (mol0.47.L0.53/g cat.h, respectively. Copyright © 2017 BCREC Group. All rights reserved Received: 20th November 2016; Revised: 26th February 2017; Accepted: 26th February 2017 How to Cite: Trivedi, S., Prasad, R., Chadha, S. (2017. Oxidation Kinetics of Propane-Air Mixture over NiCo2O4 Catalyst Emitted from LPG Vehicles. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2: 191-196 (doi:10.9767/bcrec.12.2.798.191-196 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.798.191-196

  13. El Niño Southern Oscillation (ENSO enhances CO2 exchange rates in freshwater Marsh ecosystems in the Florida everglades.

    Directory of Open Access Journals (Sweden)

    Sparkle L Malone

    Full Text Available This research examines the relationships between El Niño Southern Oscillation (ENSO, water level, precipitation patterns and carbon dioxide (CO2 exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009-2013 from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS and the long-hydroperiod site (Shark River Slough; SRS fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in both ENSO phase and annual net CO2 exchange rates co-occurred with changes in wet and dry season length and intensity. Combined with site-specific seasonality in CO2 exchanges rates, El Niño and La Niña phases magnified season intensity and CO2 exchange rates at both sites. At TS, net CO2 uptake rates were higher in the dry season, whereas SRS had greater rates of carbon sequestration during the wet season. As La Niña phases were concurrent with drought years and extended dry seasons, TS became a greater sink for CO2 on an annual basis (-11 to -110 g CO2 m-2 yr-1 compared to El Niño and neutral years (-5 to -43.5 g CO2 m-2 yr-1. SRS was a small source for CO2 annually (1.81 to 80 g CO2 m-2 yr-1 except in one exceptionally wet year that was associated with an El Niño phase (-16 g CO2 m-2 yr-1. Considering that future climate predictions suggest a higher frequency and intensity in El Niño and La Niña phases, these results indicate that changes in extreme ENSO phases will significantly alter CO2 dynamics in the Florida Everglades.

  14. SYNTHESIS AND CHARACTERIZATION OF Ni0.4Co2.6O4 SPINEL ...

    African Journals Online (AJOL)

    a

    Spinel oxides have long been known to be active in electrochemical evolution and reduction of oxygen [1, 2]. ... computer were used. Except where otherwise stated, an Hg/HgO 1 M KOH reference electrode. (0.098 V/NHE) was used. Nickel plates (1 x 2 cm²) cut from a Ni foil (99%, Aldrich) were used to realize the working ...

  15. Verifying the Rechargeability of Li-CO2 Batteries on Working Cathodes of Ni Nanoparticles Highly Dispersed on N-Doped Graphene.

    Science.gov (United States)

    Zhang, Zhang; Wang, Xin-Gai; Zhang, Xu; Xie, Zhaojun; Chen, Ya-Nan; Ma, Lipo; Peng, Zhangquan; Zhou, Zhen

    2018-02-01

    Li-CO 2 batteries could skillfully combine the reduction of "greenhouse effect" with energy storage systems. However, Li-CO 2 batteries still suffer from unsatisfactory electrochemical performances and their rechargeability is challenged. Here, it is reported that a composite of Ni nanoparticles highly dispersed on N-doped graphene (Ni-NG) with 3D porous structure, exhibits a superior discharge capacity of 17 625 mA h g -1 , as the air cathode for Li-CO 2 batteries. The batteries with these highly efficient cathodes could sustain 100 cycles at a cutoff capacity of 1000 mA h g -1 with low overpotentials at the current density of 100 mA g -1 . Particularly, the Ni-NG cathodes allow to observe the appearance/disappearance of agglomerated Li 2 CO 3 particles and carbon thin films directly upon discharge/charge processes. In addition, the recycle of CO 2 is detected through in situ differential electrochemical mass spectrometry. This is a critical step to verify the electrochemical rechargeability of Li-CO 2 batteries. Also, first-principles computations further prove that Ni nanoparticles are active sites for the reaction of Li and CO 2 , which could guide to design more advantageous catalysts for rechargeable Li-CO 2 batteries.

  16. Hierarchical MoS2 nanowires/NiCo2O4 nanosheets supported on Ni foam for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Wen, Shiyang; Liu, Yu; Zhu, Fangfang; Shao, Rong; Xu, Wei

    2018-01-01

    The hierarchical MoS2 nanowires/NiCo2O4 nanosheets (MS/NCO) supercapacitor electrode materials supported on Ni foam were synthesized by a two-step hydrothermal method. The capacitance was investigated by using various electrochemical methods including cyclic voltammetry, constant-current galvanostatic charge/discharge curves and electrochemical impedance spectroscopy. The MS/NCO networks show 7 times more capacitance (7.1 F cm-2) than pure NiCo2O4 nanosheets by CV at a scan rate of 2 mV s-1. The specific capacitance of the assembled MS/NCO//active carbon (AC) asymmetric supercapacitor could reach up to 51.7 F g-1 at a current density of 1.5 A g-1. Also, the maximum energy density of 18.4 W h kg-1 at a power density of 1200.2 W kg-1 was achieved, with 98.2% specific capacitance retention after 8000 cycles. These exciting results exhibit potential application in developing energy storage devices with high energy density and high power density.

  17. Two-step hydrothermal synthesis of NiCo2S4/Co9S8 nanorods on nickel foam for high energy density asymmetric supercapacitors

    Science.gov (United States)

    Xu, Rui; Lin, Jianming; Wu, Jihuai; Huang, Miaoliang; Fan, Leqing; Chen, Hongwei; He, Xin; Wang, Yiting; Xu, Zedong

    2018-03-01

    It is still a huge challenge to obtain a high-energy-density asymmetric supercapacitors and develop an active electrode material with excellent electrochemical characteristics. Although NiCo2S4 has been considered as one of the promising positive electrode materials for asymmetric supercapacitors, the electrochemical performance of the NiCo2S4-based positive electrodes is still relatively low and cannot meet the demand in the devices. Herein, NiCo2S4/Co9S8 nanorods with a large capacitance are synthesized via a simple two-step hydrothermal treatment. A high-performance asymmetric supercapacitor operating at 1.6 V is successfully assembled using the NiCo2S4/Co9S8 nanorods as positive electrode and activated carbon as negative electrode in 3 M KOH aqueous electrolyte, which demonstrates a fairly high energy density of 49.6 Wh kg-1 at a power density of 123 W kg-1, an excellent capacitance of 0.91 F cm-2 (139.42 F g-1) at current density of 1 mA cm-2 as well as a remarkable cycling stability due to the high physical strength, the large specific surface area, and the good conductivity for NiCo2S4/Co9S8 nanorods and the brilliant synergistic effect for NiCo2S4 and Co9S8 electrode materials. The as-prepared NiCo2S4/Co9S8 nanorods open up a new platform as positive electrode material for high-energy-density asymmetric supercapacitors in energy-storage.

  18. Carbon dioxide binding at a Ni/Fe center: synthesis and characterization of Ni(?1-CO2-?C) and Ni-?-CO2-?C:?2 O,O?-Fe? ?Electronic supplementary information (ESI) available: Characterization data for 3 and 5. CCDC 1492006 and 1492007. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc03450k Click here for additional data file. Click here for additional data file.

    OpenAIRE

    Yoo, Changho; Lee, Yunho

    2016-01-01

    The degree of CO2 activation can be tuned by incorporating a distinct electronic coordination environment at the nickel center. A mononuclear nickel carboxylate species (Ni?CO2, 3) and a dinuclear nickel?iron carboxylate species (Ni?CO2?Fe, 5) were prepared. The structure of 3 reveals a rare ?1-?C binding mode of CO2, while that of 5 shows bridging CO2 binding (?2-?C:?2 O,O?) between the nickel and iron, presented as the first example of a nickel-?-CO2-iron species. The structural analyses of...

  19. NiCo2O4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

    International Nuclear Information System (INIS)

    Wang, Ruiqi; Xia, Chuan; Wei, Nini; Alshareef, Husam N.

    2016-01-01

    Highlights: • NiCo 2 O 4 nanostructures are prepared via a simple hydrothermal method. • Outer shell of TiN is then grown through conformal atomic layer deposition. • Electrodes exhibit significantly enhanced rate capability with TiN coating. • Solid-state polymer electrolyte is employed to improve cycling stability. • Full devices show a stack power density of 58.205 mW cm −3 at 0.061 mWh cm −3 . - Abstract: Ternary transition metal oxides such as NiCo 2 O 4 show great potential as supercapacitor electrode materials. However, the unsatisfactory rate performance of NiCo 2 O 4 may prove to be a major hurdle to its commercial usage. Herein, we report the development of NiCo 2 O 4 @TiN core–shell nanostructures for all-solid-state supercapacitors with significantly enhanced rate capability. We demonstrate that a thin layer of TiN conformally grown by atomic layer deposition (ALD) on NiCo 2 O 4 nanofiber arrays plays a key role in improving their electrical conductivity, mechanical stability, and rate performance. Fabricated using the hybrid NiCo 2 O 4 @TiN electrodes, the symmetric all-solid-state supercapacitor exhibited an impressive stack power density of 58.205 mW cm −3 at a stack energy density of 0.061 mWh cm −3 . To the best of our knowledge, these values are the highest of any NiCo 2 O 4 -based all-solid-state supercapacitor reported. Additionally, the resulting NiCo 2 O 4 @TiN all-solid-state device displayed outstanding cycling stability by retaining 70% of its original capacitance after 20,000 cycles at a high current density of 10 mA cm −2 . These results illustrate the promise of ALD-assisted hybrid NiCo 2 O 4 @TiN electrodes within sustainable and integrated energy storage applications.

  20. Effect of Co(2+) and Ni(2+)-doped zinc borate nano crystalline powders by co-precipitation method.

    Science.gov (United States)

    Shim, Jaesool; Venkata Reddy, Ch; Sarma, G V S S; Narayana Murthy, P; Ravikumar, R V S S N

    2015-05-05

    A simple co-precipitation method has been used for the synthesis of Co(2+) and Ni(2+)-doped zinc borate nanopowders. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV/Vis absorption, Scanning electron microscope (SEM) with EDS and photoluminescence (PL) spectroscopies techniques has been employed for their characterization. Powder X-ray diffraction data reveals that the crystal structure belongs to monoclinic for both as-prepared samples. SEM images showed surface morphology of the prepared samples. Optical absorption spectra showed the characteristic bands of doped ions in octahedral site symmetry. From the optical absorption data crystal field and inter-electronic repulsion parameters are evaluated. The FT-IR spectra showed the characteristic vibrational bands related to ZnO, BO3 and BO4 molecules. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Three-Dimensional NiCo2O4@Polypyrrole Coaxial Nanowire Arrays on Carbon Textiles for High-Performance Flexible Asymmetric Solid-State Supercapacitor.

    Science.gov (United States)

    Kong, Dezhi; Ren, Weina; Cheng, Chuanwei; Wang, Ye; Huang, Zhixiang; Yang, Hui Ying

    2015-09-30

    In this article, we report a novel electrode of NiCo2O4 nanowire arrays (NWAs) on carbon textiles with a polypyrrole (PPy) nanosphere shell layer to enhance the pseudocapacitive performance. The merits of highly conductive PPy and short ion transport channels in ordered NiCo2O4 mesoporous nanowire arrays together with the synergistic effect between NiCo2O4 and PPy result in a high specific capacitance of 2244 F g(-1), excellent rate capability, and cycling stability in NiCo2O4/PPy electrode. Moreover, a lightweight and flexible asymmetric supercapacitor (ASC) device is successfully assembled using the hybrid NiCo2O4@PPy NWAs and activated carbon (AC) as electrodes, achieving high energy density (58.8 W h kg(-1) at 365 W kg(-1)), outstanding power density (10.2 kW kg(-1) at 28.4 W h kg(-1)) and excellent cycling stability (∼89.2% retention after 5000 cycles), as well as high flexibility. The three-dimensional coaxial architecture design opens up new opportunities to fabricate a high-performance flexible supercapacitor for future portable and wearable electronic devices.

  2. Chemical synthesis of hierarchical NiCo2S4nanosheets like nanostructure on flexible foil for a high performance supercapacitor.

    Science.gov (United States)

    Kim, D -Y; Ghodake, G S; Maile, N C; Kadam, A A; Sung Lee, Dae; Fulari, V J; Shinde, S K

    2017-08-29

    In this study, hierarchical interconnected nickel cobalt sulfide (NiCo 2 S 4 ) nanosheets were effectively deposited on a flexible stainless steel foil by the chemical bath deposition method (CBD) for high-performance supercapacitor applications. The resulting NiCo 2 S 4 sample was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical measurements. XRD and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of the ternary NiCo 2 S 4 sample with a pure cubic phase. FE-SEM and HR-TEM revealed that the entire foil surface was fully covered with the interconnected nanosheets like surface morphology. The NiCo 2 S 4 nanosheets demonstrated impressive electrochemical characteristics with a specific capacitance of 1155 F g -1 at 10 mV s -1 and superior cycling stability (95% capacity after 2000 cycles). These electrochemical characteristics could be attributed to the higher active area and higher conductivity of the sample. The results demonstrated that the interconnected NiCo 2 S 4 nanosheets are promising as electrodes for supercapacitor and energy storage applications.

  3. Effect of Temperature on the Kinetics of Sorption of Co2+ and Ni2+ Ions by a Sorbent Based on an Inositol Hexaphosphoric Acid Derivative

    Science.gov (United States)

    Yarusova, S. B.; Makarenko, N. V.; Gordienko, P. S.; Karpenko, M. A.; Novikova, E. S.

    2018-03-01

    Data on the effect temperature has on the kinetics of the removal of Co2+ and Ni2+ ions under static conditions by a sorbent based on a derivative of phytic acid fabricated from rice production waste are presented. It is shown that when the temperature is raised from 20 to 60°C, the sorption capacity of the sorbent based on phytic acid increases over the period of sorption and within 180 min reaches values of 1.4 mmol g-1 for Co2+ ions and 1.3 mmol g-1 for Ni2+ ions. It is established that for the investigated range of temperatures, order n of the sorption of Co2+ and Ni2+ ions is <1, which characterizes the reactions accompanied by diffusion processes. It is found that the process of removal of Co2+ and Ni2+ ions is characterized with low activation energy (20.74 kJ mol-1 for Co2+ ions and 14.2 kJ mol-1 for Ni2+ ions). It is also demonstrated that the sorption process in the considered time frame is best described by a kinetic model of a pseudo-second order, as is indicated by respective correlation coefficients.

  4. Adsorbed Carbon Formation and Carbon Hydrogenation for CO2 Methanation on the Ni(111) Surface: ASED-MO Study

    International Nuclear Information System (INIS)

    Choe, Sang Joon; Kang, Hae Jin; Kim, Su Jin; Park, Sung Bae; Park, Dong Ho; Huh, Do Sung

    2005-01-01

    Using the ASED-MO (Atom Superposition and Electron Delocalization-Molecular Orbital) theory, we investigated carbon formation and carbon hydrogenation for CO 2 methanation on the Ni (111) surface. For carbon formation mechanism, we calculated the following activation energies, 1.27 eV for CO 2 dissociation, 2.97 eV for the CO, 1.93 eV for 2CO dissociation, respectively. For carbon methanation mechanism, we also calculated the following activation energies, 0.72 eV for methylidyne, 0.52 eV for methylene and 0.50 eV for methane, respectively. We found that the calculated activation energy of CO dissociation is higher than that of 2CO dissociation on the clean surface and base on these results that the CO dissociation step are the ratedetermining of the process. The C-H bond lengths of CH 4 the intermediate complex are 1.21 A, 1.31 A for the C···H (1) , and 2.82 A for the height, with angles of 105 .deg. for H (1) CH and 98 .deg. for H (1) CH (1)

  5. Experimental study of mixed additive of Ni(II) and piperazine on ammonia escape in CO2 capture using ammonia solution

    International Nuclear Information System (INIS)

    Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Wen, Jiaqi; Gao, Ran; Ma, Lan; Chai, Jin

    2016-01-01

    Highlights: • Compound additive was used to obtain high CO 2 absorption efficiency and low NH 3 escape. • Both organic material and metal ion were applied as compound additive. • Influences of additives on CO 2 absorption and NH 3 escape were investigated. • Possible mechanism and products were analyzed by XRD and UV–visible spectrophotometer. - Abstract: In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

  6. Striking hierarchical urchin-like peapoded NiCo2O4@C as advanced bifunctional electrocatalyst for overall water splitting

    Science.gov (United States)

    Deng, Ju; Zhang, Huijuan; Zhang, Yan; Luo, Pan; Liu, Li; Wang, Yu

    2017-12-01

    Developing bifunctional electrocatalysts with features of wide source, low price and high efficiency for overall water splitting has the extremely vital significance on the energy front. Herein, we have designed and fabricated urchin-like peapoded NiCo2O4@C architecture for the first time, playing a prominent role in bifunctional alkaline catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M NaOH ascribed to outstanding catalytic performance and good stability. When the urchin-like peapoded NiCo2O4@C electrodes are integrated into the two-electrode system for alkaline overall water splitting, the potential as small as ∼1.608 V is a requisite for the current density of 10 mA cm-2. Given high activity and long-term stability, the harvested urchin-like peapoded NiCo2O4@C is of great potential for practical application.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-03-20

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

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

    KAUST Repository

    Eddaoudi, Mohamed

    2015-07-06

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

  9. Mace-like hierarchical MoS2/NiCo2S4 composites supported by carbon fiber paper: An efficient electrocatalyst for the hydrogen evolution reaction

    Science.gov (United States)

    Sun, Lan; Wang, Tao; Zhang, Long; Sun, Yunjin; Xu, Kewei; Dai, Zhengfei; Ma, Fei

    2018-02-01

    The rational design and preparation of earth-abundant, stable and efficient electrocatalysts for hydrogen production is currently the subject in extensive scientific and technological researches toward the future of a clean-energy society. Herein, a mace-like MoS2/NiCo2S4 hierarchical structure is designed and synthesized on carbon fiber paper via a facile hydrothermal method, and evaluated as electrocatalyst for hydrogen evolution reaction. In the MoS2/NiCo2S4/carbon fiber paper hierarchical structures, MoS2 nanosheets are dispersively distributed on the surface of NiCo2S4 nanowires, which provides an enlarged surface area, abundant interfaces and catalytic active sites. As for hydrogen evolution reaction, such MoS2/NiCo2S4/carbon fiber paper heterostructures give rise to a hydrogen evolution reaction catalytic current density of 10 mA cm-2 with a lower overpotential of 139 mV and a smaller Tafel slope of 37 mV·dec-1 than those of MoS2/carbon fiber paper and NiCo2S4/carbon fiber paper counterparts, exhibiting a prominent electrocatalytic performance. Moreover, the electrocatalytic properties change little after 5000 CV cycles and continual electrolysis for 12 h without obvious decay, respectively, demonstrating high durability and stability. The excellent hydrogen evolution reaction performances endow the hierarchical configuration MoS2/NiCo2S4/carbon fiber paper with promising alternative in HER and other related renewable energy fields.

  10. Recognition of Time-Equivalent Leaf-Based Signals of Atmospheric CO2 and El Niño Variability in Florida Wetland Species

    Science.gov (United States)

    Wagner, F.; Dilcher, D. L.; Visscher, H.; Kuerschner, W. M.

    2001-12-01

    Trees are equipped with a plastic phenotype, capable of sustained adjustment of numbers of leaf stomata to changes in atmospheric CO2 concentration. With high temporal resolution and accuracy, stomatal frequency data demonstrate that Holocene climate evolution has been influenced by century-scale CO2 fluctuations. Apart from adapting to changes in atmospheric CO2, leaf-epidermal properties are known to be sensitive to environmental factors such as water availability. In long-lived hygrophilous plants, epidermal tissue expansion is likely to be significantly influenced by changes in water availability. Concurrent analysis of the leaf morphology in CO2 sensitive trees (Myrica, Quercus, Acer) and a water-stress sensitive fern species (Osmunda regalis) from leaf assemblages preserved in peat deposits in Florida (USA), reveal distinct temporal changes in epidermal properties over the past 130 years. Stomatal frequency changes in the deciduous trees reflects the human induced CO2 increase. Epidermal-cell density changes in fern leaves, could well be interpreted in terms of El Niño / La Niña related precipitation trends. By quantifying the leaf morphological adaptation to known environmental conditions during historical times, a new paleobotanical proxy for past precipitation changes is introduced. Hence, in ENSO-sensitive regions, analysis of buried leaf assemblages offers the unique possibility of a direct recognition of time-equivalent leaf-based signals of paleo-atmospheric CO2 and El Niño variability.

  11. Direct growth of NiCo2O4 nanostructures on conductive substrates with enhanced electrocatalytic activity and stability for methanol oxidation.

    Science.gov (United States)

    Qian, Lei; Gu, Li; Yang, Li; Yuan, Hongyan; Xiao, Dan

    2013-08-21

    In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m(2) g(-1)) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity, large surface area of NiCo2O4 and the fast ion/electron transport in the electrode and at the electrolyte-electrode interface. This is important for further development of high performance non-platinum electrocatalysts for application in direct methanol fuel cells.

  12. Electrospun N-Doped Porous Carbon Nanofibers Incorporated with NiO Nanoparticles as Free-Standing Film Electrodes for High-Performance Supercapacitors and CO2 Capture.

    Science.gov (United States)

    Li, Qi; Guo, Jiangna; Xu, Dan; Guo, Jianqiang; Ou, Xu; Hu, Yin; Qi, Haojun; Yan, Feng

    2018-04-01

    Carbon nanofibers (CNF) with a 1D porous structure offer promising support to encapsulate transition-metal oxides in energy storage/conversion relying on their high specific surface area and pore volume. Here, the preparation of NiO nanoparticle-dispersed electrospun N-doped porous CNF (NiO/PCNF) and as free-standing film electrode for high-performance electrochemical supercapacitors is reported. Polyacrylonitrile and nickel acetylacetone are selected as precursors of CNF and Ni sources, respectively. Dicyandiamide not only improves the specific surface area and pore volume, but also increases the N-doping level of PCNF. Benefiting from the synergistic effect between NiO nanoparticles (NPs) and PCNF, the prepared free-standing NiO/PCNF electrodes show a high specific capacitance of 850 F g -1 at a current density of 1 A g -1 in 6 m KOH aqueous solution, good rate capability, as well as excellent long-term cycling stability. Moreover, NiO NPs dispersed in PCNF and large specific surface area provide many electroactive sites, leading to high CO 2 uptake, and high-efficiency CO 2 electroreduction. The synthesis strategy in this study provides a new insight into the design and fabrication of promising multifunctional materials for high-performance supercapacitors and CO 2 electroreduction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Synthesis of methanol from CO2hydrogenation promoted by dissociative adsorption of hydrogen on a Ga3Ni5(221) surface.

    Science.gov (United States)

    Tang, Qingli; Shen, Zhemin; Huang, Liang; He, Ting; Adidharma, Hertanto; Russell, Armistead G; Fan, Maohong

    2017-07-19

    Catalytic carbon dioxide (CO 2 ) hydrogenation to liquid fuels including methanol (CH 3 OH) has attracted great attention in recent years. In this work, density functional theory (DFT) calculations have been employed to study the reaction mechanisms of CO 2 hydrogenation to CH 3 OH on Ga 3 Ni 5 (221) surfaces. The results show that all intermediates except for the O atom prefer to adsorb on Ni sites, and dissociative adsorption of hydrogen (H 2 ) on the Ga 3 Ni 5 (221) surface is almost barrierless and highly exothermic, favoring CO 2 hydrogenation. Moreover, the presence of Ga indeed enhances the dissociative adsorption of H 2 , and this is verified by the projected density of states (PDOS) analysis. Importantly, three possible reaction pathways based on formate (HCOO) and hydrocarboxyl (COOH) formations and reverse water gas shift (rWGS) with carbon monoxide (CO) hydrogenation have been discussed. It is found that CO 2 reduction to CH 3 OH in these pathways prefers to occur entirely via the Langmuir-Hinshelwood (L-H) mechanism. COOH generation is the most favorable pathway because the HCOO and rWGS with CO hydrogenation pathways have high energy barriers and the resulting HCOOH intermediate in the HCOO pathway is unstable. In the COOH reaction pathway, CO 2 is firstly hydrogenated to trans-COOH, followed by the formation of COH via three isomers of COHOH, its hydrogenation to trans-HCOH, and then the production of CH 3 OH via a CH 2 OH intermediate.

  14. Response of CO2 and H2O fluxes in a mountainous tropical rainforest in equatorial Indonesia to El Niño events

    DEFF Research Database (Denmark)

    Olchev, A.; Ibrom, Andreas; Panferov, O.

    2015-01-01

    The possible impact of El Niño–Southern Oscillation (ENSO) events on the main components of CO2 and H2O fluxes in a pristine mountainous tropical rainforest growing in Central Sulawesi in Indonesia is described. The fluxes were continuously measured using the eddy covariance method for the period...

  15. Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Luoxiao Zhou

    2017-09-01

    Full Text Available Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4 core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2 and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

  16. Quantifying the impact of El Niño-driven variations in temperature and precipitation on regional atmospheric CO2 growth rate variations

    Science.gov (United States)

    Keppel-Aleks, G.; Butterfield, Z.; Doney, S. C.; Dlugokencky, E. J.; Miller, J.; Morton, D. C.

    2017-12-01

    Quantifying the climatic drivers of variations in atmospheric CO2 observations over a range of timescales is necessary to develop a mechanistic understanding of the global carbon cycle that will enable prediction of future changes. Here, we combine NOAA cooperative global air sampling network CO2 observations, remote sensing data, and a flux perturbation model to quantify the feedbacks between interannual variability in physical climate and the atmospheric CO2 growth rate. In particular, we focus on the differences between the 1997/1998 El Niño and the 2015/2016 El Niño during which atmospheric CO2 increased at an unprecedented rate. The flux perturbation model was trained on data from 1997 to 2012, and then used to predict regional atmospheric CO2 growth rate anomalies for the period from 2013 through 2016. Given gridded temperature anomalies from the Hadley Center's Climate Research Unit (CRU), precipitation anomalies from the Global Precipitation Climatology Project (GPCP), and fire emissions from the Global Fire Emissions Database (GFEDv4s), the model was able to the reproduce regional growth rate variations observed at marine boundary layer stations in the NOAA network, including the rapid CO2 growth rate in 2015/2016. The flux perturbation model output suggests that the carbon cycle responses differed for1997 and 2015 El Niño periods, with tropical precipitation anomalies causing a much larger net flux of CO2 to the atmosphere during the latter period, while direct fire emissions dominated the former. The flux perturbation model also suggests that high temperature stress in the Northern Hemisphere extratropics contributed almost one-third of the CO2 growth rate enhancement during the 2015 El Niño. We use satellite-based metrics for atmospheric column CO2, vegetation, and moisture to corroborate the regional El Niño impacts from the flux perturbation model. Finally, we discuss how these observational results and independent data on ocean air-sea flux

  17. Hierarchically constructed NiCo2S4@Ni(1-x)Co x (OH)2 core/shell nanoarrays and their application in energy storage.

    Science.gov (United States)

    Zhou, Weiwei; Yu, Kun; Wang, Dong; Chu, Jing; Li, Jieying; Zhao, Limin; Ding, Chunyan; Du, Yu; Jia, Xingtao; Wang, Huatao; Wen, Guangwu

    2016-06-10

    We report a new type of core-shell heterostructure consisting of a rod-like NiCo2S4 (NCS) core and an urchin-like Ni(1-x)Co x (OH)2 (NCOH) shell via a simple hydrothermal route coupled with a facile electrodeposition. NCS nanorod arrays (NRAs) can not only act as excellent electrochemically active materials by themselves, but they can also serve as hierarchical porous scaffolds capable of fast electron conduction and ion diffusion for loading a large amount of additional active materials. Moreover, it is observed that the urchin-like NCOH nanosheets coating could bind the inner NCS nanorods together and thereby reinforce the whole structure mechanically. Meanwhile, more effective pathways for electrons are available in the NCS@NCOH hybrids than an individual NCS nanorod. Benefiting from both structural and compositional features, the NCS@NCOH electrode exhibits greatly improved electrochemical performance with high capacity (3.54 C cm(-2) at 1 mA cm(-2)) and excellent cycling stability (78% capacity retention after 4000 cycles). Moreover, a battery-type device is also fabricated by using NCS@NCOH as a positive electrode and activated carbon (AC) as a negative electrode, displaying high capacity (2.51 C cm(-2) at 2 mA cm(-2)) and good durability (88.8% capacity retention after 4000 cycles) as well.

  18. Facile synthesis of three-dimensional structured carbon fiber-NiCo2O4-Ni(OH)2 high-performance electrode for pseudocapacitors

    Science.gov (United States)

    Li, Wei; Xin, Lipeng; Xu, Xin; Liu, Qida; Zhang, Ming; Ding, Shujiang; Zhao, Mingshu; Lou, Xiaojie

    2015-01-01

    Two-dimensional textured carbon fiber is an excellent electrode material and/or supporting substrate for active materials in fuel cells, batteries, and pseudocapacitors owing to its large surface area, high porosity, ultra-lightness, good electric conductivity, and excellent chemical stability in various liquid electrolytes. And Nickel hydroxide is one of the most promising active materials that have been studied in practical pseudocapacitor applications. Here we report a high-capacitance, flexible and ultra-light composite electrode that combines the advantages of these two materials for pseudocapacitor applications. Electrochemical measurements demonstrate that the 3D hybrid nanostructured carbon fiber–NiCo2O4–Ni(OH)2 composite electrode shows high capacitance, excellent rate capability. To the best of our knowledge, the electrode developed in this work possesses the highest areal capacitance of 6.04 F cm−2 at the current density of 5 mA cm−2 among those employing carbon fiber as the conductor. It still remains 64.23% at 40 mA cm−2. As for the cycling stability, the initial specific capacitance decreases only from 4.56 F cm−2 to 3.35 F cm−2 after 1000 cycles under a current density of 30 mA cm−2. PMID:25787769

  19. An Asymmetric Supercapacitor with Mesoporous NiCo2O4 Nanorod/Graphene Composite and N-Doped Graphene Electrodes

    Science.gov (United States)

    Mao, J. W.; He, C. H.; Qi, J. Q.; Zhang, A. B.; Sui, Y. W.; He, Y. Z.; Meng, Q. K.; Wei, F. X.

    2018-01-01

    In the present work, mesoporous NiCo2O4 nanorod/graphene oxide (NiCo2O4/GO) composite was prepared by a facile and cost-effective hydrothermal method and meanwhile, N-doped graphene (N-G) was fabricated also by a hydrothermal synthesis process. NiCo2O4/GO composite and N-G were used as positive and negative electrodes for the supercapacitor, respectively, which all displayed excellent electrochemical performances. The NiCo2O4/GO composite electrode exhibited a high specific capacitance of 709.7 F g-1 at a current density of 1 A g-1 and excellent rate capability as well as good cycling performance with 84.7% capacitance retention at 6 A g-1 after 3000 cycles. A high-voltage asymmetric supercapacitor (ASC) was successfully fabricated using NiCo2O4/GO composite and N-G as the positive and negative electrodes, respectively, in 1 M KOH aqueous electrolyte. The ASC delivered a high energy density of 34.4 Wh kg-1 at a power density of 800 W kg-1 and still maintained 28 Wh kg-1 at a power density of 8000 W kg-1. Furthermore, this ASC showed excellent cycling stability with 94.3% specific capacitance retained at 5 A g-1 after 5000 cycles. The impressive results can be ascribed to the positive synergistic effects of the two electrodes. Evidently, our work provides useful information for assembling high-performance supercapacitor devices.

  20. Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants

    Science.gov (United States)

    Sun, Shichen; Awadallah, Osama; Cheng, Zhe

    2018-02-01

    It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.

  1. Metal Doping Effect of the M-Co2P/Nitrogen-Doped Carbon Nanotubes (M = Fe, Ni, Cu) Hydrogen Evolution Hybrid Catalysts.

    Science.gov (United States)

    Pan, Yuan; Liu, Yunqi; Lin, Yan; Liu, Chenguang

    2016-06-08

    The enhancement of catalytic performance of cobalt phosphide-based catalysts for the hydrogen evolution reaction (HER) is still challenging. In this work, the doping effect of some transition metal (M = Fe, Ni, Cu) on the electrocatalytic performance of the M-Co2P/NCNTs (NCNTs, nitrogen-doped carbon nanotubes) hybrid catalysts for the HER was studied systematically. The M-Co2P/NCNTs hybrid catalysts were synthesized via a simple in situ thermal decomposition process. A series of techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, transmission electron microscopy, and N2 sorption were used to characterize the as-synthesized M-Co2P/NCNTs hybrid catalysts. Electrochemical measurements showed the catalytic performance according to the following order of Fe-Co2P/NCNTs > Ni-Co2P/NCNTs > Cu-Co2P/NCNTs, which can be ascribed to the difference of structure, morphology, and electronic property after doping. The doping of Fe atoms promote the growth of the [111] crystal plane, resulting in a large specific area and exposing more catalytic active sites. Meanwhile, the Fe(δ+) has the highest positive charge among all the M-Co2P/NCNTs hybrid catalysts after doping. All these changes can be used to contribute the highest electrocatalytic activity of the Fe-Co2P/NCNTs hybrid catalyst for HER. Furthermore, an optimal HER electrocatalytic activity was obtained by adjusting the doping ratio of Fe atoms. Our current research indicates that the doping of metal is also an important strategy to improve the electrocatalytic activity for the HER.

  2. Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H2S and CO2

    Science.gov (United States)

    Sui, Yiyong; Sun, Chong; Sun, Jianbo; Pu, Baolin; Ren, Wei; Zhao, Weimin

    2017-01-01

    The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H2S/CO2 environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H2S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni3S2, NiS, or Ni3S4, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate. PMID:28772995

  3. Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H2S and CO2

    Directory of Open Access Journals (Sweden)

    Yiyong Sui

    2017-06-01

    Full Text Available The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H2S/CO2 environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H2S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni3S2, NiS, or Ni3S4, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate.

  4. The Impact of Ce-Zr Addition on Nickel Dispersion and Catalytic Behavior for CO2 Methanation of Ni/AC Catalyst at Low Temperature

    Directory of Open Access Journals (Sweden)

    Minh Cam Le

    2017-01-01

    Full Text Available The CO2 methanation was studied over 7 wt.% nickel supported on Ce0.2Zr0.8O2/AC to evaluate the correlation of the structural properties with catalytic performance. The catalysts were investigated in more detail by means of X-ray diffraction (XRD, transmission electron microscopy (TEM, and scanning electron microscopy (SEM. A sample of 7 wt.% nickel loading supported on activated carbon (AC was also prepared for comparison. The results demonstrated that the ceria-zirconia solid solution phase could disperse and stabilize the nickel species more effectively and resulted in stronger interaction with nickel than the parent activated carbon phase. Therefore, 7% Ni/Ce0.2Zr0.8O2/AC catalyst exhibited higher activity for CO2 reduction than 7% Ni//AC. It can attain 85% CO2 conversion at 350°C and have a CH4 selectivity of 100% at a pressure as low as 1 atm. The high activity of prepared catalysts is attributed to the good interaction between Ni and Ce0.2Zr0.8O2 and the high CO2 adsorption capacity of the activated carbon as well.

  5. Facilitated Transport of Zn2+, Ni2+ and Co2+ by Liquid Membrane Using a Tertio Amine as Carrier

    Directory of Open Access Journals (Sweden)

    Hassaine-Sadi F.

    2013-04-01

    Full Text Available The environmental impact of the emissions of heavy metals (Zn2+, Ni2+, Co2+ present in the industrial effluents become extensive more and more. The discharge of toxic metals into environment is a serious problem facing numerous industries. So the search for extraction techniques to remove those heavy metals are increasing interest. Liquid membranes have shown great potentiel in this way especially in cases where metal concentrations are relatively low and other techniques cannot be applied efficiently.The fundamental parameters influencing the transport of the zinc (II, nickel (II and cobalt (II through the liquid membrane have been examined (the acidity, the time of transport. The coupling that makes itself thanks to the membrane (extractant + diluent permits to define the different phases of transfer and to determine the mechanisms of transportation membranaires. In thi study of th facilitated transport of zinc, nickel, cobalt ions by liquid membranes containing Tri-n-octyl amine as carrier. The chemical variable exam permitted to determine the parameters giving the extraction efficiency and reextraction optimum. Some performances have been gotten so much to the level of the extraction that of the reextraction. A chemical modelization has allowed to identify the extraction mechanism and transport. The coupling required a real optimization of the set of the parameters. The symmetrical behavior of the two compartments showed that the extraction – reextraction association permits to achieve a transportation, one counter - transportation and a positive coupling. This lets predict an applications as well in the field of metalliferous processing liquid waste not very in charge as in that of the industrial wastes. This also allows an effective protection of the environment while being profitable.

  6. System approach on solar hydrogen generation and the gas utilization; Taiyo energy ni yoru suiso no seisei oyobi sono riyo system ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, I.; Hirooka, N.; Deguchi, Y.; Narita, D. [Meiji University, Tokyo (Japan)

    1997-11-25

    An apparatus is developed to establish a system which allows utilization of hydrogen safely and easily, and its applicability to a hydrogen system for domestic purposes is tested. The system converts solar energy by the photovoltaic cell unit into power, which is used to generate hydrogen by electrolysis of water at the hydrogen generator, stores hydrogen in a metal hydride , and sends stored hydrogen to the burner and fuel cell units. It is found that a hydrogen occluding alloy of LaNi4.8Al0.2 stores hydrogen to approximately 80% when cooled to 20 to 25degC, and releases it to 10% when heated to 40degC. The fuel cell uses a solid polymer as the electrolyte. The hydrogen gas burner is a catalytic combustion burner with a Pt catalyst carried by expanded Ni-Al alloy. The optimum distance between the burner and object to be heated is 22mm. High safety and fabrication simplicity are confirmed for use for domestic purposes. The system characteristics will be further investigated. 4 refs., 8 figs.

  7. A facile enhancement in battery-type of capacitive performance of spinel NiCo2O4 nanostructure via directly tuning thermal decomposition temperature

    International Nuclear Information System (INIS)

    Jiang, Shu; Sun, Yujing; Dai, Haichao; Ni, Pengjuan; Lu, Wangdong; Wang, Yilin; Li, Zhen; Li, Zhuang

    2016-01-01

    A facile, low cost and time-saving method to synthesize porous NiCo 2 O 4 nanoplatelet and nanorod structures is developed via a simple two-step route. A flakes assembled precursor containing Ni-Co hydroxides is firstly prepared via a facile, low-cost chemical bath coprecipitation process only using diluted ammonia solution as a precipitant to govern over the nucleation, growth, and agglomeration processes.Then, porous NiCo 2 O 4 nanoplatelet and nanorod structures are successfully obtained through pyrolyzing the above precursor. The influence of the calcination temperature is mainly studied on the pyrolysis reaction. The calcination temperature has statistically significant effects on the morphology and structure evolution, crystallinity, electronic conductivity and the electrochemical performances of the products. The optimized, nanoplatelet predominated NiCo 2 O 4 spinel, calcinated at 300 ∘C for 6 h (denoted as NC300), has excellent crystallinity and electric conductivity. It shows a superior-specific capacitance of 1362F g −1 at a current density of 1 A g −1 .When the current density increases to 16 A g −1 , the specific capacity still retains 964 F g −1 (70.8% capacity retention). Ragone plot indicates maximum energy density of our porous NC300 electrode is 75.67 W h kg −1 at a power density of 499.82 W kg −1 . Cycle-life tests show that the specific capacitance of NC300 is nearly stable between 300 and 1500 cycles, indicating its potential use in energy-storage field.The simplicity and practicability of the modified pyrolysis process may facilitate the successful commercial applications in electrochemical capacitors for nanostructured NiCo 2 O 4 spinel.

  8. g-C3N4/NiAl-LDH 2D/2D Hybrid Heterojunction for High-Performance Photocatalytic Reduction of CO2into Renewable Fuels.

    Science.gov (United States)

    Tonda, Surendar; Kumar, Santosh; Bhardwaj, Monika; Yadav, Poonam; Ogale, Satishchandra

    2018-01-24

    2D/2D interface heterostructures of g-C 3 N 4 and NiAl-LDH are synthesized utilizing strong electrostatic interactions between positively charged 2D NiAl-LDH sheets and negatively charged 2D g-C 3 N 4 nanosheets. This new 2D/2D interface heterojunction showed remarkable performance for photocatalytic CO 2 reduction to produce renewable fuels such as CO and H 2 under visible-light irradiation, far superior to that of either single phase g-C 3 N 4 or NiAl-LDH nanosheets. The enhancement of photocatalytic activity could be attributed mainly to the excellent interfacial contact at the heterojunction of g-C 3 N 4 /NiAl-LDH, which subsequently results in suppressed recombination, and improved transfer and separation of photogenerated charge carriers. In addition, the optimal g-C 3 N 4 /NiAl-LDH nanocomposite possessed high photostability after successive experimental runs with no obvious change in the production of CO from CO 2 reduction. Our findings regarding the design, fabrication and photophysical properties of 2D/2D heterostructure systems may find use in other photocatalytic applications including H 2 production and water purification.

  9. Morphology Control of Carbon-Free Spinel NiCo2O4 Catalysts for Enhanced Bifunctional Oxygen Reduction and Evolution in Alkaline Media.

    Science.gov (United States)

    Devaguptapu, Surya V; Hwang, Sooyeon; Karakalos, Stavros; Zhao, Shuai; Gupta, Shiva; Su, Dong; Xu, Hui; Wu, Gang

    2017-12-27

    Spinel NiCo 2 O 4 is considered a promising precious metal-free catalyst that is also carbon-free for oxygen electrocatalysis. Current efforts mainly focus on optimal chemical doping and substituent to tune its electronic structures for enhanced activity. Here, we study its morphology control and elucidate the morphology-dependent catalyst performance for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Three types of NiCo 2 O 4 catalysts with significantly distinct morphologies were prepared using temple-free, Pluronic-123 (P-123) soft, and SiO 2 hard templates, respectively, via hydrothermal methods followed by calcination. Whereas the hard-template yields spherelike dense structures, soft-template assists the formation of a unique nanoneedle cluster assembly containing abundant meso- and macropores. Furthermore, the effect of morphology of NiCo 2 O 4 on their corresponding bifunctional catalytic performance was systematically investigated. The flowerlike nanoneedle assembly NiCo 2 O 4 catalyst via the soft-template method exhibited the highest catalytic activity and stability for both ORR and OER. In particular, it exhibited an onset and half-wave potentials of 0.94 and 0.82 V versus reversible hydrogen electrode, respectively, for the ORR in alkaline media. Although it is still inferior to Pt, the NiCo 2 O 4 represents one of the best ORR catalyst compared to other reported carbon-free oxides. Meanwhile, remarkable OER activity and stability were achieved with an onset potential of 1.48 V and a current density of 15 mA/cm 2 at 1.6 V, showing no activity loss after 20 000 potential cycles (0-1.9 V). The demonstrated stability is even superior to Ir for the OER. The morphology-controlled approach provides an effective solution to create a robust three-dimensional architecture with increased surface areas and enhanced mass transfer. Importantly, the soft template can yield a high degree of spinel crystallinity with ideal

  10. Fe--12Ni--4Co--2Mo--.05Ti alloy for use at 770K and below

    International Nuclear Information System (INIS)

    Whitaker, B.W.

    1975-10-01

    A variant of the maraging class of steels is proposed for application at 77 0 K and below where a combination of very high strength and good toughness is required. The alloy has a composition of Fe-12Ni-4Co-2Mo-0.05Ti where low interstitial content. The as quenched and quenched and aged structures were completely martensitic with a prior austenitic grain size of 10 to 12 μm. This structure had a Y.S. of 138.5 ksi and 154 ksi before and after aging respectively. All aging was done at 444 0 C for 4 hours. The DBTT was shown to lie above 77 0 K as measured by C/sub v/ testing. Based on dilatometric studies of the α → γ and γ → α transformation temperatures a cycling treatment consisting of reportedly heating to above the A/sub f/ temperature followed by a water quench was utilized to further reduce the prior γ grain size to approximately 4 to 6 μm. The structure was completely martensitic and possessed a Y.S. of 151 ksi at 77 0 K in the unaged condition with a Y.S./K/sub IC/ ratio of 1.9 while the aged structure showed a Y.S. of 162 ksi with a Y.S./K/sub IC/ ratio of 1.3. C/sub v/ testing showed the DBTT to lie between 77 0 K and 4.2 0 K. Further grain refinement was accomplished by a 2 phase decomposition procedure which resulted in a grain size of 1 to 2 μm. The structure which contained decreasing amounts of austenite with temperature (3.0 percent at R.T. to 1.0 percent at 4.2 0 K) showed the best combination of strength and ductility at 4.2 0 K. A Y.S. of 205 ksi with a Y.S./K/sub IC/ ratio of 0.84 was achieved before aging. The aged structure was brittle at 4.2 0 K with a Y.S. of 218 ksi and a Y.S./K/sub IC/ ratio of 0.425

  11. Microwave Assisted Synthesis of Porous NiCo2O4 Microspheres: Application as High Performance Asymmetric and Symmetric Supercapacitors with Large Areal Capacitance.

    Science.gov (United States)

    Khalid, Syed; Cao, Chuanbao; Wang, Lin; Zhu, Youqi

    2016-03-03

    Large areal capacitance is essentially required to integrate the energy storage devices at the microscale electronic appliances. Energy storage devices based on metal oxides are mostly fabricated with low mass loading per unit area which demonstrated low areal capacitance. It is still a challenge to fabricate supercapacitor devices of porous metal oxides with large areal capacitance. Herein we report microwave method followed by a pyrolysis of the as-prepared precursor is used to synthesize porous nickel cobaltite microspheres. Porous NiCo2O4 microspheres are capable to deliver large areal capacitance due to their high specific surface area and small crystallite size. The facile strategy is successfully demonstrated to fabricate aqueous-based asymmetric &symmetric supercapacitor devices of porous NiCo2O4 microspheres with high mass loading of electroactive materials. The asymmetric &symmetric devices exhibit maximum areal capacitance and energy density of 380 mF cm(-2) &19.1 Wh Kg(-1) and 194 mF cm(-2) &4.5 Wh Kg(-1) (based on total mass loading of 6.25 &6.0 mg) respectively at current density of 1 mA cm(-2). The successful fabrication of symmetric device also indicates that NiCo2O4 can also be used as the negative electrode material for futuristic asymmetric devices.

  12. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

    Directory of Open Access Journals (Sweden)

    Vincenzo Naso

    2013-07-01

    Full Text Available The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO. The bed material simultaneously acts as reforming catalyst and CO2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH4 removal, with conversions near 100%, while the simultaneous CO2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO2 during the duty cycle.

  13. Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported Ni and Co Catalysts: Full Factorial Design Screening

    Directory of Open Access Journals (Sweden)

    M. Anwar Hossain

    2018-01-01

    Full Text Available In this study, the potential of dry reforming reaction over CaFe2O4 supported Ni and Co catalysts were investigated. The Co/CaFe2O4 and Ni/CaFe2O4 catalysts were synthesized using wet impregnation method by varying the metal loading from 5-15 %. The synthesized catalysts were tested in methane dry reforming reaction at atmospheric pressure and reaction temperature ranged 700-800 oC. The catalytic performance of the catalysts based on the initial screening is ranked as 5%Co/CaFe2O4 < 10%Co/CaFe2O4 < 5%Ni/CaFe2O4 < 10%Ni/CaFe2O4 according to their performance. The Ni/CaFe2O4 catalyst was selected for further investigation using full factorial design of experiment. The interaction effects of three factors namely metal loading (5-15 %, feed ratio (0.4-1.0, and reaction temperature (700-800 oC were evaluated on the catalytic activity in terms of CH4 and CO2 conversion as well as H2 and CO yield. The interaction between the factors showed significant effects on the catalyst performance at metal loading, feed ratio and reaction temperature of 15 %, 1.0, and 800 oC. respectively. The 15 wt% Ni/CaFe2O4 was subsequently characterized by Thermogravimetric (TGA, X-ray Diffraction (XRD, Field Emission Scanning Electron Microscopy (FESEM, Energy Dispersive X-ray Spectroscopy (EDX, X-ray Photoelectron Spectroscopy (XPS, N2-physisorption, Temperature Programmed Desorption (TPD-NH3, TPD-CO2, and Fourier Transform Infra Red (FTIR to ascertain its physiochemical properties.  This study demonstrated that the CaFe2O4 supported Ni catalyst has a good potential to be used for syngas production via methane dry reforming. Copyright © 2018 BCREC Group. All rights reserved Received: 5th May 2017; Revised: 8th August 2017; Accepted: 9th August 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Hossain, M.A., Ayodele, B.V., Cheng, C.K., Khan, M.R. (2018. Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported

  14. New type ternary NiAlCe layered double hydroxide photocatalyst for efficient visible-light photoreduction of CO2 into CH4

    Science.gov (United States)

    Li, Ji; (Bill Yang, Y. J.

    2018-02-01

    New type of ternary NiAlCe layered double hydroxide photocatalyst was synthesized by a simple hydrothermal reaction. The obtained photocatalyst shows efficient visible-light activity for CO2 reduction to CH4. We have investigated the optimal Ce content in the catalyst and analyzed the mechanism by materials characterization. Additionally, a novel alkali etching method was used to construct the porous structure. The effect of the porosity and morphologies on the activity is investigated. It is found that the ternary NiAlCe layered double hydroxide photocatalyst with porosity showing the best photocatalytic activity among all the samples. Based on the characterization and first principle calculation, the detailed photocatalytic mechanism of the ternary NiAlCe layered double hydroxide photocatalyst is deduced.

  15. NiCo2O4 surface coating Li[Ni0.03Mn1.97]O4 micro-/nano- spheres as cathode material for high-performance lithium ion battery

    Science.gov (United States)

    Ye, Pan; Dong, Hui; Xu, Yunlong; Zhao, Chongjun; Liu, Dong

    2018-01-01

    Here we report a novel transitional metal oxide (NiCo2O4) coated Li[Ni0.03Mn1.97]O4 micro-/nano- spheres as high-performance Li-ion battery cathode material. A thin layer of ∼10 nm NiCo2O4 was formed by simple wet-chemistry approach adjacent to the surface of Li[Ni0.03Mn1.97]O4 micro-/nano- spheres, leading to significantly enhanced battery electrochemical performance. The optimized sample(1 wt%) not only delivers excellent discharge capacity and cycling stability improvement at both room temperature and elevated temperatures, but also effectively prevents Mn dissolution while retaining its coating structure intact according to XRF and TEM results. The CV and EIS break-down analysis indicated a much faster electrochemical reaction kinetics, more reversible electrode process and greatly reduced charge transfer and Warburg resistance, clearly illustrating the dual role of NiCo2O4 coating to boost electron transport and Li+ diffusion, and alleviation of manganese dissolving. This approach may render as an efficient technique to realize high-performance lithium ion battery cathode material.

  16. Fiscal 1996 survey of potential international cooperation for a long-term scenario on CO2 reduction; 1996 nendo CO2 sakugen ni kakawaru choki shinario ni kansuru kokusai kyoryoku kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the purpose of working out a CO2 reduction scenario and a CO2 policy introduction scenario, a survey was conducted of comparisons between ten and several models which are world-known and models of the New Earth 21, potential international cooperation to be carried out in the future, etc. The survey included organizations which are developing CO2 policy evaluation models, survey reports made in the past, details of literature for the analysis and arrangement. From the result, details of the questionnaire survey and organizations to be surveyed were decided on for the questionnaire survey. Objects for the survey were 7 countries and 22 organizations, and survey items were places for information exchange, sending/receiving of researchers, exchange of input data, comparative calculation based on the common database, joint research work, economy, the carbon tax, impact, renewable energy, how to handle and think of the carbon isolation, etc. As a result of the survey, proposed were a workshop on CO2 reduction, a comparative study of simulation models, etc. 25 refs., 50 figs., 12 tabs.

  17. 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.

  18. Assessment of global environmental impacts by utilizing methodology of LCA on solar water heater for dwellings; LCA shuho ni yoru taiyonetsu onsuiki no kankyo fuka hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Kamoshida, J. [Shibaura Institute of Technology, Tokyo (Japan); Asai, S. [Yazaki Corp., Tokyo (Japan)

    1997-11-25

    CO2 emission was quantified through the life cycle of a solar water heater to assess its environment impact. Although LCA (life cycle assessment) originally sums up I/O of all materials and energy through the whole life cycle of a product to examine environment impact, this assessment was carried out for only CO2. Calculation of CO2 emission assumed a natural circulating solar water heater of 200 l in effective hot water capacity, 2.78m{sup 2} in effective collecting area, and 0.5 in average annual collecting efficiency of total solar radiation, and an auxiliary city gas heat source for compensating insufficient heat quantity. The total CO2 emission in the life cycle of a solar water heater was obtained from an industrial association table assuming the life cycles of 10 and 20 years. CO2 emission was estimated to be 5407.1kg-CO2 and 10665.2kg-CO2 for 10 and 20 years, respectively. CO2 emission due to city gas was largest in the total CO2 emission in the life cycle. As a result, for reduction of CO2 emission due to a solar water heater, improvement of equipment efficiency was most important. 6 refs., 5 figs., 3 tabs.

  19. SÍNTESE E CARACTERIZAÇÃO DE COBALTITA DE NIQUEL (NiCo2O4 OBTIDAS PELO MÉTODO DOS PRECURSORES POLIMÉRICOS

    Directory of Open Access Journals (Sweden)

    Marcelo Moizinho Oliveira

    2016-04-01

    Full Text Available A cobaltita de níquel NiCo2O4 de estrutura do tipo espinélia e suas soluções sólidas (NixCo1-xO4, tem sido amplamente utilizadas em materiais para armazenamento eletrônico de informação, catodo de baterias recargáveis de lítio, termistores, sensores de gás, eletrocatálise e supercapacitores, devido a sua elevada condutividade elétrica e propriedades antiferromagnéticas. Entretanto este material apresenta baixa estabilidade térmica em torno dos 400 °C, que ocasiona a perda de NiO, afetando de maneira significativa as propriedades físicas e estruturais do material produzido. Poucos trabalhos na literatura abordam procedimentos adequados para sua obtenção desse material sem a presença de fases cristalinas secundárias. Neste trabalho a cobaltita de níquel (NiCo2O4, foi preparada pelo método dos precursores poliméricos numa razão mássica de 60/40 entre o agente quelante (ácido cítrico e o polimerizante (etilenoglicol. O gel polimérico obtido foi calcinado a 350 °C para a eliminação do material orgânico e em seguida tratado termicamente às temperaturas de 450 °C, 550 °C e 750 °C. Os materiais obtidos foram caracterizados por TG/DSC, Difração de raios X (DRX, Refinamento Rietveld e Espectroscopia Raman. Os resultados mostraram que é possível se obter a fase cobaltita de níquel (NiCo2O4 independente do tratamento térmico empregado.

  20. Catalisadores sol-gel de Ni-SiO2 e Ni-Al2O3 aplicados na reforma de metano com CO2 = Ni-SiO2 and Ni-Al2O3 sol-gel catalysts applied to methane reforming with CO2

    Directory of Open Access Journals (Sweden)

    Giane Gonçalves

    2005-01-01

    Full Text Available A reação de reforma do metano com CO2 apresenta-se como um processopromissor de geração de gás de síntese e hidrogênio. Neste sentido, foram preparados catalisadores de níquel-sílica e níquel-alumina pelo método sol-gel, com carga metálica nominal de 8% em massa. Os catalisadores foram caracterizados por redução à temperatura programada, análise termogravimétrica e determinação da área superficial específica. A reação de reforma do metano com CO2 foi realizada em um micro-reator contendo 500 mg de catalisador, previamente ativado em uma mistura redutora contendo hidrogênio. Osensaios de reforma a seco do metano foram realizados a 800°C, na pressão atmosférica, por um período de 12 horas, com uma razão molar de alimentação de [CO2:CH4] = 6. Os produtos da reação foram analisados por cromatografia gasosa. Dentre os catalisadoresavaliados, nas condições de reação estudadas, o catalisador de níquel suportado em sílica foi o que apresentou o melhor desempenho.The dry reforming reaction of methane comes as a promising process of syngas and hydrogen. Nickel catalysts on Al2O3 and SiO2 were synthesized by sol-gel method, with metalic load of 8% weight. The catalysts were characterized by temperature programmed reduction (TPR, termogravimetry analysis (TGA and specific surface area measurements (BET. The dry reforming reaction was performed in a micro reactor packed with 500 mg of catalyst, previously activated in atmosphere of hydrogen. The dry reforming tests were done at 800oC and atmospheric pressure by a period of 12 hours, with a molar ratio in the feeding of [CO2:CH4] = 6. The products of the reaction were analyzed by gas chromatograph. The Ni-SiO2 catalysts showed better performance.

  1. La-Sr-Ni-Co-O based perovskite-type solid solutions as catalyst precursors in the CO 2 reforming of methane

    Science.gov (United States)

    Valderrama, Gustavo; Kiennemann, Alain; Goldwasser, Mireya R.

    La 1- xSr xNi 0.4Co 0.6O 3 and La 0.8Sr 0.2Ni 1- yCo yO 3 solid solutions with perovskite-type structure were synthesized by the sol-gel resin method and used as catalytic precursors in the dry reforming of methane with CO 2 to syngas, between 873 and 1073 K at atmospheric pressure under continuous flow of reactant gases with CH 4/CO 2 = 1 ratio. These quaternary oxides were characterized by X-ray diffraction (XRD), BET specific surface area and temperature-programmed reduction (TPR) techniques. XRD analyses of the more intense diffraction peaks and cell parameter measurements showed formation of La-Sr-Ni-Co-O solid solutions with La 0.9Sr 0.1CoO 3 and/or La 0.9Sr 0.1NiO 3 as the main crystallographic phases present on the solids depending on the degree of substitution. TPR analyses showed that Sr doping decreases the temperature of reduction via formation of intermediary species producing Ni 0, Co 0 with particle sizes in the range of nanometers over the SrO and La 2O 3 phases. These metallic nano particles highly dispersed in the solid matrix are responsible for the high activity shown during the reaction and avoid carbon formation. The presence of Sr in doping quantities also promotes the secondary reactions of carbon formation and water-gas shift in a very small extension during the dry reforming reaction.

  2. Fiscal 1995 investigation on biological fixation of carbon dioxide; 1995 nendo seibutsuteki CO2 kotei ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    To cope with the global warming caused by CO2, an investigation was conducted into biological fixation. It is necessary to make a many-sided and comprehensive study on the mechanism of CO2 fixation, the scale (area and carbon holding density), the rate and the environmental impact of the introduction of the technology and the technical problems, and to make a quantitative evaluation of each of the methods in order to make them practical proposals. The global ecosystem is classified into the land biota and ocean biota, and each typical ecosystem was surveyed in terms of the surface area, the carbon holding amount (presently existing amount), the net primary production amount, the required nutrient salt amount, the transpiration rate, etc. Next, a discussion was made on the increasing effect of the carbon fixation amount by changing the present ecosystem from the aspect of scale and rate. At the same time, a study was carried out of energy efficiency, economical efficiency and problems. Last, elementary technology was taken up which seems to be important for implementing measures for the biological carbon fixation. As to the ocean, it is necessary to obtain information, which is not sufficient to utilize marine biota for CO2 fixation, especially on the mechanism of depth-direction transfer of organism and its quantitative grasp. As to the land, one of the measures is conversion of the ecosystem where the amount of carbon fixed is small to the ecosystem where the amount is large. 249 refs., 58 figs., 51 tabs.

  3. Electrochemical Energy Storage Application and Degradation Analysis of Carbon-Coated Hierarchical NiCo2S4 Core-Shell Nanowire Arrays Grown Directly on Graphene/Nickel Foam.

    Science.gov (United States)

    Zou, Rujia; Yuen, Muk Fung; Yu, Li; Hu, Junqing; Lee, Chun-Sing; Zhang, Wenjun

    2016-02-01

    We developed a new electrode comprising thin carbon layer coated hierarchical NiCo2S4 core-shell nanowire arrays (NiCo2S4@C CSNAs) on graphene/Ni foam (Ni@G) substrates. The electrode showed outstanding electrochemical characteristics including a high specific capacitance of 253 mAh g(-1) at 3 A g(-1), high rate capability of 163 mAh g(-1) at 50 A g(-1) (~64.4% of that at 3 A g(-1)), and long-term cycling stability with a capacity retention of 93.9% after 5000 cycles. Comparative studies on the degradation of hierarchical NiCo2S4 CSNA electrodes with and without carbon coatings revealed that the morphology pulverization, structural separation at core/shell interface, and irretrievably chemical composition change of NiCo2S4 CSNAs electrode are major factors that deteriorate the electrochemical performance of the electrodes without carbon coating. The favorable roles of carbon coatings on hierarchical NiCo2S4 CSNAs were further clarified: (1) serving as a physical buffering layer that suppresses the structural breakdown; (2) retarding the chemical composition conversion of the NiCo2S4 CSNAs; and (3) providing extra path for charge transition in addition to the NiCo2S4 core nanowires. Understanding of the degradation mechanisms and the significance of the surface carbon coatings would provide useful guidelines for the design of new electrode materials for high-performance electrochemical devices.

  4. Ni/SiO2 Catalyst Prepared with Nickel Nitrate Precursor for Combination of CO2 Reforming and Partial Oxidation of Methane: Characterization and Deactivation Mechanism Investigation

    Directory of Open Access Journals (Sweden)

    Sufang He

    2015-01-01

    Full Text Available The performance of Ni/SiO2 catalyst in the process of combination of CO2 reforming and partial oxidation of methane to produce syngas was studied. The Ni/SiO2 catalysts were prepared by using incipient wetness impregnation method with nickel nitrate as a precursor and characterized by FT-IR, TG-DTA, UV-Raman, XRD, TEM, and H2-TPR. The metal nickel particles with the average size of 37.5 nm were highly dispersed over the catalyst, while the interaction between nickel particles and SiO2 support is relatively weak. The weak NiO-SiO2 interaction disappeared after repeating oxidation-reduction-oxidation in the fluidized bed reactor at 700°C, which resulted in the sintering of metal nickel particles. As a result, a rapid deactivation of the Ni/SiO2 catalysts was observed in 2.5 h reaction on stream.

  5. Removal of Heavy Metals Pb2+, Cu2+, Zn2+, Cd2+, Ni2+, Co2+ and Fe3+ from Aqueous Solutions by using Xanthium Pensylvanicum

    Directory of Open Access Journals (Sweden)

    Jaber SALEHZADEH

    2013-11-01

    Full Text Available The hazardous ill effects of heavy metals on the environment and public health is a matter of serious concern. Biosorption is emerging as a sustainable effective technology. Heavy metals in water resources are one of the most important environmental problems of countries. The intensification of industrial activity and environmental stress greatly contributes to the significant rise of heavy metal pollution in water resources making threats on terrestrial and aquatic life. The toxicity of metal pollution is slow and interminable, as these metal ions are non bio-degradable. The adsorption capacity of Xanthium Pensylvanicum towards metal ions such as Pb2+, Cu2+, Zn2+, Cd2+, Ni2+, Co2+ and Fe3+, was studied. The adsorption capacity was performed by batch experiments as a function of process parameters (such as sorption time and pH. Experimental results showed that the removal percentages increasing of metal ions at pH=4, initial concentration of metal ions 10 mg/L, and after 90 min of shaking was: Zn2+ < Cd2+ < Cu2+ < Pb2+ < Ni2+ < Fe3+ < Co2+.

  6. Characterization of a metal resistant Pseudomonas sp. isolated from uranium mine for its potential in heavy metal (Ni2+, Co2+, Cu2+, and Cd2+) sequestration.

    Science.gov (United States)

    Choudhary, Sangeeta; Sar, Pinaki

    2009-05-01

    Heavy metal sequestration by a multimetal resistant Pseudomonas strain isolated from a uranium mine was characterized for its potential application in metal bioremediation. 16S rRNA gene analysis revealed phylogenetic relatedness of this isolate to Pseudomonas fluorescens. Metal uptake by this bacterium was monophasic, fast saturating, concentration and pH dependent with maximum loading of 1048 nmol Ni(2+) followed by 845 nmol Co(2+), 828 nmol Cu(2+) and 700 nmol Cd(2+)mg(-1) dry wt. Preferential metal deposition in cell envelope was confirmed by TEM and cell fractionation. FTIR spectroscopy and EDX analysis revealed a major role of carboxyl and phosphoryl groups along with a possible ion exchange mechanism in cation binding. Binary system demonstrated selective metal binding affinity in the order of Cu(2+)>Ni(2+)>Co(2+)>Cd(2+). A comparison with similar metal uptake reports considering live bacteria strongly indicated the superiority of this strain in metal sequestration, which could be useful for developing efficient metal removal system.

  7. Microwave-Assisted Synthesis of NiCo2O4 Double-Shelled Hollow Spheres for High-Performance Sodium Ion Batteries

    Science.gov (United States)

    Zhang, Xiong; Zhou, Yanping; Luo, Bin; Zhu, Huacheng; Chu, Wei; Huang, Kama

    2018-03-01

    The ternary transitional metal oxide NiCo2O4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo2O4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt, and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized product was tested as an anode material in a sodium ion battery, was found to exhibit a high reversible specific capacity of 511 mAh g-1 at 100 mA g-1, and deliver high capacity retention after 100 cycles. [Figure not available: see fulltext.

  8. Hierarchical nanostructured NiCo2O4 as an efficient bifunctional non-precious metal catalyst for rechargeable zinc-air batteries

    Science.gov (United States)

    Prabu, Moni; Ketpang, Kriangsak; Shanmugam, Sangaraju

    2014-02-01

    A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo2O4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated. Single-phase, NCO with an average diameter of 100 nm, porous interconnected fibrous morphology was revealed by FESEM and FETEM analysis. The hierarchical nanostructured 1D-spinel NiCo2O4 materials showed a remarkable electrocatalytic activity towards oxygen reduction and evolution in an aqueous alkaline medium. The extraordinary bi-functional catalytic activity towards both ORR and OER was observed by the low over potential (0.84 V), which is better than that of noble metal catalysts [Pt/C (1.16 V), Ru/C (1.01 V) and Ir/C (0.92 V)], making them promising cathode materials for metal-air batteries. Furthermore, the rechargeable zinc-air battery with NCO-A1 as a bifunctional electrocatalyst displays high activity and stability during battery discharge, charge, and cycling processes.A nickel-doped cobalt oxide spinel structure is a promising non-precious metal electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal-air batteries and water electrolyzers operating with alkaline electrolytes. One dimensional NiCo2O4 (NCO) nanostructures were prepared by using a simple electrospinning technique with two different metal precursors (metal nitrate/PAN and metal acetylacetonate/PAN). The effect of precursor concentration on the morphologies was investigated. Single-phase, NCO with an average diameter of 100 nm, porous interconnected fibrous morphology was revealed by FESEM and FETEM analysis. The hierarchical nanostructured 1D-spinel NiCo2O4 materials showed a

  9. Synthesis of Supported NiPt Bimetallic Nanoparticles, Methods for Controlling the Surface Coverage of Ni Nanoparticles With Pt, Methods Of Making NiPt Multilayer Core-Shell Structures and Application of the Supported Catalysts for CO2 Reforming

    KAUST Repository

    Li, Lidong

    2015-06-25

    Embodiments of the present disclosure provide for supported Ni/Pt bimetallic nanoparticles, compositions including supported NiPt nanoparticles, methods of making supported NiPt nanoparticles, methods of using supported NiPt nanoparticles, and the like.

  10. Outline of investigation on restraint of carbon dioxide generation by green chemistry. 1999.1-1999.3; 1998 nendo green chemistry ni yoru CO2 hassei yokusei ni kakawaru chosa kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Investigations were conducted into the above in some leading OECD (Organization for Economic Cooperation and Development) member states. Green chemistry is a new concept in which clean technology, environment-friendly chemistry, and the like are combined, and is a chemical solution for reducing or stopping the use or generation of materials, products, by-products, solvents, reagents, etc., which are dangerous to health and environments, throughout the whole life cycle of chemicals covering the processes of their designing, manufacturing, dumping, and recycling. In this fiscal year, the actual state of the generation of biomass, regarded as representative of reproducible materials, and its feasibility as chemical resources were investigated. In an effort at finding out chemical reactions safer to health and causing less environmental impact, investigations were also conducted into the recent trends of catalysts, novel reactions for organic syntheses, use of supercritical fluids, photocatalysts, biomimetic processes, etc. The development of substitutes for plastic additives was also studied. Since acceptance by the citizenry is quite important for green chemistry to take effect, educating and enlightening activities in the U.S., Britain, France, and Germany were inquired into. (NEDO)

  11. Choice of precipitant and calcination temperature of precursor for synthesis of NiCo2O4 for control of CO-CH4 emissions from CNG vehicles.

    Science.gov (United States)

    Trivedi, Suverna; Prasad, Ram

    2018-03-01

    Compressed natural gas (CNG) is most appropriate an alternative of conventional fuel for automobiles. However, emissions of carbon-monoxide and methane from such vehicles adversely affect human health and environment. Consequently, to abate emissions from CNG vehicles, development of highly efficient and inexpensive catalysts is necessary. Thus, the present work attempts to scan the effects of precipitants (Na 2 CO 3 , KOH and urea) for nickel cobaltite (NiCo 2 O 4 ) catalysts prepared by co-precipitation from nitrate solutions and calcined in a lean CO-air mixture at 400°C. The catalysts were used for oxidation of a mixture of CO and CH 4 (1:1). The catalysts were characterized by X-ray diffractometer, Brunauer-Emmett-Teller surface-area, X-ray photoelectron spectroscopy; temperature programmed reduction and Scanning electron microscopy coupled with Energy-Dispersive X-Ray Spectroscopy. The Na 2 CO 3 was adjudged as the best precipitant for production of catalyst, which completely oxidized CO-CH 4 mixture at the lowest temperature (T 100 =350°C). Whereas, for catalyst prepared using urea, T 100 =362°C. On the other hand the conversion of CO-CH 4 mixture over the catalyst synthesized by KOH limited to 97% even beyond 400°C. Further, the effect of higher calcination temperatures of 500 and 600°C was examined for the best catalyst. The total oxidation of the mixture was attained at higher temperatures of 375 and 410°C over catalysts calcined at 500 and 600°C respectively. Thus, the best precipitant established was Na 2 CO 3 and the optimum calcination temperature of 400°C was found to synthesize the NiCo 2 O 4 catalyst for the best performance in CO-CH 4 oxidation. Copyright © 2017. Published by Elsevier B.V.

  12. Cultivation of spirulina platensis and its growth behavior controlling cultivation medium; Baiyoeki sosei no seigyo ni yoru spirulina platensis no baiyo oyobi sono zoshoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, K.; Fujita, K. [Babcock-Hitachi K.K., Tokyo (Japan)

    1996-01-20

    Cultivation of Spirulina platensis while controlling pH and nitrate ion in the culture medium was investigated in order to obtain a high density culture. In the cultivation of Spirulina platensis using sodium bicarbonate as a carbon source, the pH value increased during growth of Spirulina, and then the growth stopped at a pH value of more than 12. The cell concentration reached 2.2g/l by maintaining a pH range of 8.5 to 10.0 using CO2 gas without controlling the nitrate ion concentration. By controlling the pH and adding nitrate to a concentration of 2.0g/l, the cell concentration reached 4.2g/l at 350 hours. It was found that the cell concentration was about four times that of the culture without controlling pH and nitrate. 4 refs., 6 figs.

  13. Study of Paramagnetic Monohydrates MeSO4.1H2O (Me = Mn2+, Co2+, Fe2+, Ni2+, Cu2+

    Directory of Open Access Journals (Sweden)

    Jelšovská Kamila

    2000-09-01

    Full Text Available Nuclear magnetic resonance (NMR of protons of crystrallization water in isomorphous paramagnetic monohydrates MeSO4.1H2O with Me = Mn2+ , Co2+ , Fe2+ , Ni2+ , Cu2+ is studied in the present paper. Several physically important parameters characterizing the studied substances were derived from the NMR spectra. In this paper we analysed the dependences of the NMR second moment M2 on the magnitude of the external magnetic field induction Br and the temperature. The proton NMR spectra in paramagnetic hydrates have an asymmetric form caused by the anisotropy of the local magnetic field acting on resonating nuclei and their second moments, M2, depend linearly on the square of the external magnetic field Br. The parameters M20 (the part of the second moment M2 which corresponds to the nuclear dipole-dipole interactions and á which characterize nuclear dipole-dipole interactions of protons and paramagnetic ions, respectively, are derived from experimentally obtained dependences of M2 vs Br2. The measurements were performed at the room temperature. Calculations were realized using the approximation where two nearest neighbour ions Me2+ to each water molecule are considered. The temperature dependence of the second moment, which was realised in the temperature range 123-313 K, was more informative than the field one. Besides the individual dependences M2(T measured at fr1 and fr2 we analysed the temperature dependence of the difference ∆M2(T. Beside the second moment M20 the Curie-Weiss constant è and the magnetic moment µi of paramagnetic ions were determined from the temperature dependences. The parameters è and M20 were determined directly from the experimental data. Some knowledge on the crystalline structure for the studied substance was required for the calculation of the magnetic moment µi. By means of the classification of substances according to the Curie-Weiss parameter, the negative value of the temperature parameter è for all studied

  14. Observation of fine structure in auger electron spectra for chemical state analysis. Auger denshi bunko ho ni yoru jotai bunseki no tame no spectrum bisai kozo kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Hirokawa, K. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research); Fukuda, Y. (Shizuoka Univ., Shizuoka (Japan). Research Inst. of Electronics); Suzuki, K. (Nippon Steel Corp., Tokyo (Japan)); Hashimoto, S. (NKK Corp., Tokyo (Japan)); Suzuki, T. (Kawasaki Steel Corp., Kobe (Japan)); Usuki, N. (Sumotomo Metal Industries, Ltd., Osaka (Japan)); Gennai, N. (Kobelco Research Inst., Inc., Kobe (Japan)); Yoshida, S. (Daido Steel Co. Ltd., Nagoya (Japan)); Koda, M. (Nisshin Steel Co. Ltd., Tokyo (Japan)); Sezaki, H. (Hitachi Metals, Ltd., Tokyo (Japan)); Horie, H. (Kyushu Electronic Metal Co. Ltd., Fukuoka (Japan)); Tanaka, A. (ULVAC-PHI Incorporated, Kanagawa (Japan)); Otsubo, T. (The Japan Iron and Steel Federation, Tokyo (Japan))

    1991-09-01

    Cooperative researches by participation of 8 analytical laboratories such as Institute for Materials Research, Tohoku University and Steel Research Center, NKK Corporation, etc. were conducted wherein the common samples of Au, Fe, Ni, Al and their oxides were measured by means of Auger electron spectra. By virtue of an elastic scattering peak apparatus and the standardization of the sample locations, peak energy values of Auger electron spectra obtained by the respective equipment are neutrally in good agreement. Auger profiles (peak intensity) considerably change according to the respective units and the measuring conditions. When the spectra are as sharp as in LMM, LMV and LVV of Fe, Ni and their oxides, and emerge, as in the case of LMM and LMV, in mutually close energy value, the difference in the ratio of spectrum intensity by the respective machines and measuring methods is small in metal oxides, but, in the case of LVV LMM, the state analysis can be made by its slight change. 10 refs., 9 figs., 1 tab.

  15. Study of Ni-dopped MnCo2O4 Yolk-Shell Submicron-spheres with Fast Li+ Intercalation Pseudocapacitance As An Anode for High-Performance Lithium Ion Batteries

    International Nuclear Information System (INIS)

    Wu, Lijun; Lang, Junwei; Wang, Shuai; Zhang, Peng; Yan, Xingbin

    2016-01-01

    Spinel Ni-dopped MnCo 2 O 4 powder with fast Li + intercalation pseudocapacitance is prepared from transition metal carbonates of Ni, Co and Mn as precursors through a solvothermal synthesis followed by an annealing treatment. As-made products are nanovoids submicron-spheres (the diameter is 500 nm–700 nm) with an obvious yolk-shell structure and uniform elements distribution. As an anode material with fast Li + intercalation pseudocapacitance for lithium-ion battery (LIB), the Ni-dopped MnCo 2 O 4 submicron-spheres exhibit an impressively first discharge efficiency (70%) and outstanding large-current cycling performance. The excellent electrochemical performance is closely ascribed to Li + intercalation pseudocapacitance and the yolk-shell structure, which can effectively prevent the particles from being pulverized, and alleviate the volume changes of particles during the cycling process. In addition, the doping of Ni metal element to MnCo 2 O 4 greatly enhances the electrochemical stability of MnCo 2 O 4 , due to the complementarities and synergies between the three metallic elements during the process of Li insertion or extraction reactions.

  16. Effects of inorganic acids and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process.

    Science.gov (United States)

    Zhang, Jian; Xia, Yuguo; Zhang, Li; Chen, Dairong; Jiao, Xiuling

    2015-11-07

    In-depth understanding of the sol-gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4(-) on the surface of the γ-AlOOH particles, and the hydrogen in HSO4(-) pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg(-1). The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol-gel process.

  17. Chemical state and distribution of iodine deposits on 17% Cr/12% Ni steel oxidised in CO2/CH3I gas mixtures

    International Nuclear Information System (INIS)

    Allen, G.C.; Tyler, J.W.

    1990-01-01

    Iodine-131 is one of the most important volatile fission product elements with respect to radiobiological impact, and the characterisation of its chemical state and distribution on reactor surfaces is required for reactor safety assessments. To this end, duplicate samples of Type 316 (17% Cr/12% Ni) stainless steel oxidised in CO 2 /CH 3 I gas mixtures and previously characterised using X-ray photoelectron spectroscopy have been examined using Raman spectroscopy. The aim is to improve our understanding of the way in which iodine is distributed throughout the oxide scale and to identify its chemical state. In this paper we present Raman spectra recorded from a series of stainless steel specimens together with spectra recorded from a number of standard iodine compounds. It is demonstrated that the technique is well suited as a fingerprint method of species identification, can differentiate between the chemical state of iodine as iodide and iodate and can analyse thin oxide films (5-50 nm). Identification of iodine deposits in these oxide films at concentrations of ≤2 at% was not achieved however, there being insufficient iodine present to distinguish any peaks present from the background signal. It is concluded that local concentrations of iodine in oxide inclusions of different composition/morphology on the steel surface does not occur to any extent. (orig.)

  18. Selective laser melting of an Al86Ni6Y4.5Co2La1.5 metallic glass: Processing, microstructure evolution and mechanical properties

    International Nuclear Information System (INIS)

    Li, X.P.; Kang, C.W.; Huang, H.; Zhang, L.C.; Sercombe, T.B.

    2014-01-01

    In this study, single line scans at different laser powers were carried out using selective laser meting (SLM) equipment on a pre-fabricated porous Al 86 Ni 6 Y 4.5 Co 2 La 1.5 metallic glass (MG) preform. The densification, microstructural evolution, phase transformation and mechanical properties of the scan tracks were systematically investigated. It was found that the morphology of the scan track was influenced by the energy distribution of the laser beam and the heat transfer competition between convection and conduction in the melt pool. Due to the Gaussian distribution of laser energy and heat transfer process, different regions of the scan track experienced different thermal histories, resulting in a gradient microstructure and mechanical properties. Higher laser powers caused higher thermal stresses, which led to the formation of cracks; while low power reduced the strength of the laser track, also inducing cracking. The thermal fluctuation at high laser power produced an inhomogeneous chemical distribution which gave rise to severe crystallization of the MG, despite the high cooling rate. The crystallization occurred both within the heat affected zone (HAZ) and at the edge of melt pool. However, by choosing an appropriate laser power crack-free scan tracks could be produced with no crystallization. This work provides the necessary fundamental understanding that will lead to the fabrication of large-size, crack-free MG with high density, controllable microstructure and mechanical properties using SLM

  19. Comparative toxicity of VO3-, CrO42-, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ to lettuce seedlings

    International Nuclear Information System (INIS)

    Berry, W.L.

    1978-01-01

    Lettuce seeds imbibed, germinated, and grown in a 0.1-strength modified Hoagland culture solution were subjected to a series of increasing concentrations of individual heavy metals up to and exceeding lethal levels. After an exposure of 5 days, seedlings were harvested, examined, and measured to determine toxic effects. A log--log plot of root length (yield) vs. heavy metal concentration was made for each metal to produce a dose response curve. The curves showed a growth plateau at low concentrations of the respective metals which was equivalent to the growth of the control. All metals inhibited root growth and caused lethal toxicity in the sub- and low-milliequivalent range. When concentrations of the tested metals exceeded their thresholds of acute toxicity, root growth was inhibited. In the zone of inhibition, between the acute toxic threshold and complete inhibition, the log--log dose response curves were approximately linear or were a series of linear steps. The threshold toxicity and the response slope were characteristic for each metal. Seedling lettuce showed a monophasic response to VO 3 - , Cu 2+ , and Zn 2+ ; a biphasic response to CrO 4 2 -, Mn 2+ , Ni 2+ , and Cd 2+ ; and a quadraphasic response to Co 2+ . The acute toxicity threshold on an equivalent basis increased according to the following sequence: Cd 2+ much less than VO 3 - 2+ 2+ 2+ 4 2- 2+ much less than Mn 2+ . On this basis, Cd 2+ is the most toxic of the trace elements tested

  20. Synthesis and characterization of Ni0.4Co2.6O4 spinel mixed oxides powder: study of its surface properties by voltammetry, x-ray, ftir, UV-VIS-NIR spectroscopy and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Makhtar Guene

    2005-12-01

    Full Text Available Electrochemical studies were carried out on Ni0.4Co2.6O4 powders prepared by sol-gel via propionic acid method using cyclic and steady state voltammetries. The oxide surface was characterized by scanning electron microscopy (SEM, X-ray diffraction, UV-vis-NIR and FTIR spectroscopies. The results showed that the formation of homogeneous oxide with a single spinel phase occurred at 350°C. The surface redox couple NiOOH/Ni(OH2 is confined on the surface material l.

  1. Feasibility study of international cooperation on the chemical CO2 fixation and effective utilization technology in FY 1996; 1996 nendo kagakuteki CO2 koteika yuko riyo gijutsu ni kakawaru kokusai kyoryoku kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In this survey, candidate organizations to cooperate internationally in the development of chemical CO2 fixation technologies have been selected, and possible forms of the cooperation each organization would participate in have been examined. The chemical CO2 fixation technology project of RITE (Research Institute of Innovation Technology for the Earth) involves the essential themes of CO2 separation membrane technology, catalytic hydrogenation reaction technology, and hydrogen production/supply technology, as well as the overall system. Through the arrangement, 19 international research institutes were selected as the potential candidates for international research cooperation. Either direct visit or questionnaire by mail was conducted to these institutes. The purposes of international cooperation in each of essential study theme are to review the possibility of improving technologies in each theme by introducing new technologies, and to review the possibilities of promoting practical implementation of chemical CO2 fixation system. The research institutes to be reviewed as partners for joint research are summarized. 10 figs., 16 tabs.

  2. Report on survey of international cooperation possibility on chemical CO2 fixation and utilization technology in FY 1997; 1997 nendo chosa hokokusho (kagakuteki CO2 koteika yuko riyo gijutsu ni kakawaru kokusai kyoryoku kanosei chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This survey focused on the end of the more promising companion and promoting the international cooperation on chemical CO2 fixation and utilization technology. As a result, the way of the carrying-forward of the international cooperation with more than one companion could be arranged beforehand. It led to getting an arrangement about a secrecy agreement respectively with Lurgi company and ABB company in Europe, and to providing a catalyst sample developed by RITE to implement an examination by the other party and to show related technical information. In addition, it concluded a cooperation agreement about a total system of the chemical CO2 fixation and utilization technology and methanol synthesis with ZSW. In Australia, negotiation about international cooperation with CSIRO which is a federal research organization and CRC (Cooperative Research Centre) for renewable energy has been started. The ideal circumstances are being ready for the chemical CO2 fixation project for which the international cooperation with the country where the natural energy is rich like Australia is essential when coming to practical use. To do alternating current with further high density in the following year it is desired to build a concrete study cooperation system. 1 fig., 4 tabs.

  3. Investigational research on CO2 isolation technology in fiscal 1995; 1995 nendo nisanka tanso no kakuri gijutsu ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The paper studied present technical subjects and future study subjects of the CO2 isolation technology in order to clarify technical and social problems and the developmental subjects of the CO2 isolation technology and related technologies for separating/concentrating CO2 emitted in relation to quantity consumption of fossil fuel and storing it in ocean or underground. Main items for the study were: (1) investigational study of the technology of CO2 ocean storage, (2) investigational study of environmental effect assessment in storing CO2 in ocean, (3) investigational study of the technology of CO2 ocean storage, etc. Technologies required for the ocean isolation were arranged such as CO2 storage, injection, dispersion technique, CO2 behavior simulation, and the developmental subjects were extracted. Further, in the deep-sea bottom storage method, a simulation to calculate the range of PH effects was conducted presuming the specified amount of CO2 and applying known physical values, and evaluation of the CO2 ocean discharge/solution method was made. A method was also studied for experiments on water bacteria and benthos. 127 refs., 102 figs., 81 tabs.

  4. Basic investigation on promotion of joint implementation in fiscal 2000. Survey on energy saving and CO2 emission reduction in Cilacap Refinery; 2000 nendo kyodo jisshi nado suishin kiso chosa hokokusho. Cilacap seiyusho ni okeru shoene CO2 sakugen chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    With an objective of saving energy and reducing greenhouse gas emission, a basic survey has been performed on the atmospheric crude oil distillation units and the high vacuum distillation units at Cilacap Refinery in Indonesia. The first site survey in September 2000 has carried out a survey on the situation of the facilities and operation upon obtaining the facility data and operation information from Pertamina. As a result, it was revealed that there is a room of improvement in the heat recovery, whereas a modification design was executed on the improvement proposals on the heat exchanger system. However, the second site survey in November 2000 has revealed that Pertamina had executed in 1998 through 1999 the de-bottlenecking project on the crude oil atmospheric distillation units (two units) and the high vacuum distillation units (two units), by which the capability has been expanded, and the heat recovery rate has been increased. It is not possible to look for extremely large enhancement of the heat recovery rate beyond that point, and the reduction of CO2 emission would also be small. As a result of discussions, the present project was found capable of reducing annually the CO2 emission by 36,500 tons. (NEDO)

  5. Fiscal 1997 report on the survey of biological CO2 fixation using arid land and oligotrophic waters; 1997 nendo chosa hokokusho (kansochi, hin`eiyo kaiiki wo riyoshita seibutsuteki CO2 kotei ni kansuru chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This survey is aimed to investigate various measures to be taken for biological CO2 fixation, to synthetically study feasibilities of the measures from various aspects of CO2 fixation mechanism, scale, speed, and environmental effects and technical problems in case of introducing those, and to assess the measures quantitatively. In this fiscal year, a study was proceeded with of possibilities of carbon fixation by afforestation and that by fertilization into ocean. The paper defined significance of afforestation in arid land, and especially advantages in conducting researches in West Australia. Relationships were examined among afforestation, precipitation and topography. The result of the survey was described of water- and salt-transfer simulation methods. Studies of arid land were made in terms of photosynthetic speed, transpiration speed, soil characteristics, measuring methods for precipitation and vaporization amount, and the examples. Seven places of Leonora where water source and water quality were examined were selected, and the measuring results were described. The paper summed up the state of utilization of biomass energy obtained from forest and commented on a scenario on tree-planting. Finally, a possibility was stated of the carbon fixation by fermentation into ocean. 178 refs., 121 figs., 53 tabs.

  6. Fiscal 1997 survey report on the project on energy conservation by effectively using building energy in Indonesia; 1997 nendo chosa hokokusho (Indonesia ni okeru biru energy yuko riyo ni yoru sho energy ka project chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    As an energy conservation method for a model building, the following eight methods were selected and trially calculated of the effects. 1) adoption of high efficient illumination apparatus, 2) introduction of an illuminance control system, 3) cooling water secondary pump with invertor, 4) ventilation control for parking lots, 5) heightening of the established temperature, 6) improvement of the 24-hour run chiller, 7) elevator with invertor, and 8) introduction of the photovoltaic power generation. As a result, it was found out that energy was totally reduced by about 3,837.4 MWh/yr or 25.6%. If viewed from the amount of reduction in greenhouse gas, the amount of CO2 emitted from office buildings, approximately 0.22 million t-C/yr, decreases to approximately 0.16 million t-C/yr. Further, approximately 0.93 million t-C/yr, the amount of CO2 emitted from commercial use facilities such as office buildings, department stores and hotels is reduced to about 0.69 million t-C/yr, thanks to the effect of the project on energy saving buildings, which made a CO2 reduction by approximately 0.24 million t-C/yr possible. Validity of the project on energy conservation in Indonesia was confirmed. 2 refs., 55 figs., 38 tabs.

  7. A binder-free NiCo2O4nanosheet/3D elastic N-doped hollow carbon nanotube sponge electrode with high volumetric and gravimetric capacitances for asymmetric supercapacitors.

    Science.gov (United States)

    Tong, Hao; Yue, Shihong; Lu, Liang; Jin, Fengqiao; Han, Qiwei; Zhang, Xiaogang; Liu, Jie

    2017-11-09

    To increase the volumetric and gravimetric capacitances of supercapacitors, a new class of electrode materials with high electrochemical activity and favorable structures is extremely desired. In this work, a hollow novel nitrogen-doped 3D elastic single-walled carbon nanotube sponge (NSCS) which is ultra lightweight with the lowest density of 0.8 mg cm -3 , and has a high open surface structure for electrolyte accessibility and excellent compressible properties as the electrode scaffold has been successfully fabricated by the pyrolysis method which could produce the carbon nanotube sponge easily on a large scale without high-cost and time-consuming processes. Moreover, a NiCo 2 O 4 nanosheet supported on the NSCS has been successfully fabricated. The highest volumetric and gravimetric capacitance of this electrode is 790 F cm -3 at 1.43 g cm -3 and 1618 F g -1 at 0.54 g cm -3 with excellent cycling stability. The density of NiCo 2 O 4 /NSCS electrode was adjusted by mechanical compression and the most favorable density of the film for both high volumetric and gravimetric capacitances obtained was 1.21 g cm -3 . The thick NiCo 2 O 4 /NSCS film of 72 μm has been fabricated at this favorable density, presenting both high volumetric and gravimetric capacitances of 597 F cm -3 and 1074 F g -1 at 1 A g -1 , respectively, indicating that the structure of the NSCS is extremely feasible for obtaining a thick film electrode with excellent volumetric and gravimetric capacitances. Furthermore, an asymmetric supercapacitor of NiCo 2 O 4 /NSCS//NGN/CNTs was fabricated, exhibiting a high gravimetric energy density of 47.65 W h kg -1 at 536 W kg -1 and a volumetric energy density of 33.44 W h L -1 at 376.16 W L -1 .

  8. Features of electronic properties of band ferromagnets Co2 MeAl and Fe2 MeAl (Me  =  Ti, V, Cr, Mn, Fe, Ni)

    Science.gov (United States)

    Kourov, N. I.; Marchenkov, V. V.; Korolev, A. V.; Lukoyanov, A. V.; Shirokov, A. A.; Perevozchikova, Yu A.

    2017-11-01

    The results of the low-temperature (2  MeAl (Me  =  Ti, V, Cr, Mn, Fe, Ni) ordered in the L21 crystal structure are presented. A comparative analysis of the behaviour of electronic properties as a function of the number of valence electrons z in the alloys Co2 MeAl and Fe2 MeAl is carried out.

  9. EFFECT OF THE REDUCTION TEMPERATURE INTO CATALYTIC ACTIVITY OF Ni SUPPORTED BY TiO2, AL2O2 AND TiO2/AL2O3 FOR CONVERSION CO2 INTO METHANE

    Directory of Open Access Journals (Sweden)

    Hery Haerudin

    2010-06-01

    Full Text Available Nickel catalysts, containing 6% (w/w of nickel, have been prepared using TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9. The catalysts were used for CO2 conversion into methane. The characteristics of catalysts were studied by determination of its specific surface area, temperature programmed reaction technique and X-ray diffraction. The specific surface area were varied slightly by different temperature of reduction, namely after reduction at 300°C it was 39, 120 and 113 m2/g and after reduction at 400°C it was 42, 135  and 120 m2/g for 6% nickel catalysts supported on TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9 respectively. Temperature program reaction studies (TPO and TPR showed that NiTiOx species were possibly formed during the pretreatments which has shown by the shift of its peak to the lower temperature on Ni catalyst, that supported on mixture of TiO2-Al2O3 compared with catalysts supported on individual TiO2 or Al2O3. The nickel species on reduced Ni catalysts supported on TiO2 and on mixture of TiO2-Al2O3 could be detected by X-ray diffraction. The catalyst's activities toward CH4 formation were affected by the reduction temperature. Activity for CH4 formation was decreased in the following order: Ni/ TiO2 > Ni/ TiO2: Al2O3 > Ni/ Al2O3 and Ni/ TiO2: Al2O3 > Ni/ TiO2> Ni/ Al2O3, when catalysts were reduced at 300°C or 400°C respectively. The CO2 conversion was decreased in the following order: Ni/ Al2O3 > Ni/ TiO2: Al2O3 > Ni/ TiO2 when catalysts were reduced at 300°C or 400°C respectively.   Keywords: nickel catalyst, carbondioxide, methane

  10. Ultrasound assisted dispersion of different amount of Ni over ZSM-5 used as nanostructured catalyst for hydrogen production via CO2 reforming of methane

    International Nuclear Information System (INIS)

    Vafaeian, Yaser; Haghighi, Mohammad; Aghamohammadi, Sogand

    2013-01-01

    Graphical abstract: A series of Ni/ZSM-5 nanocatalysts with different amount of Ni were prepared via ultrasound assisted method and characterized with XRD, FESEM, TEM, BET and FTIR techniques. The research deals with catalyst development for dry reforming of methane with the aim of reaching the most stable catalyst specifically over nano-sized catalysts. About more than 99% of Ni particles size is less than 100 nm for the sample prepared with 8% Ni, which is essential to the relative suppression of the carbon formation on catalysts. Catalyst prepared with 8% Ni content showed superior activity in process expected due to its better catalytic properties. - Highlights: • Using ZSM-5 zeolite in dry reforming of methane. • Employing ultrasound energy in synthesis of Ni/ZSM-5 nanocatalyst. • Enhancement of Ni particles size to meet desired catalyst at lower amount of Ni loading. • Dry reforming of methane over Ni/ZSM-5 nanocatalyst with different Ni-loading. • Superior activity of Ni/ZSM-5 nanocatalyst synthesized with 8% Ni content. - Abstract: Carbon dioxide reforming of methane is an interesting route for synthesis gas production especially over nanostructured catalysts. The present research deals with nanocatalyst development by sonochemical method for dry reforming of methane with the aim of reaching the most efficient nanocatalyst. Effect of Ni metal content, one of the most significant variables, on the properties of the ZSM-5 supported nanocatalysts was taken into account. The Ni/ZSM-5 nanocatalysts were prepared via assisted traditional impregnation method via ultrasound irradiation and characterized with XRD, FESEM, TEM, BET and FTIR techniques. Comparison of XRD patterns implies that the peaks related to NiO become sharper by increasing metal content over the support. In the case of nanocatalysts with lower metal content (3% and 8%), the beneficial influence of ultrasound assisted procedure become more pronounced and the observed reduction in

  11. High-temperature electrolysis of CO2-enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells

    Science.gov (United States)

    Kim, Si-Won; Bae, Yonggyun; Yoon, Kyung Joong; Lee, Jong-Ho; Lee, Jong-Heun; Hong, Jongsup

    2018-02-01

    To mitigate CO2 emissions, its reduction by high-temperature electrolysis using solid oxide cells is extensively investigated, for which excessive steam supply is assumed. However, such condition may degrade its feasibility due to massive energy required for generating hot steam, implying the needs for lowering steam demand. In this study, high-temperature electrolysis of CO2-enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells is considered to satisfy such needs. The effect of internal and external steam supply on its electrochemical performance and gas productivity is elucidated. It is shown that the steam produced in-situ inside the fuel-electrode by a reverse water gas shift reaction may decrease significantly the electrochemical resistance of dry CO2-fed operations, attributed to self-sustaining positive thermo-electrochemical reaction loop. This mechanism is conspicuous at low current density, whereas it is no longer effective at high current density in which total reactant concentrations for electrolysis is critical. To overcome such limitations, a small amount of external steam supply to the CO2-enriched feed stream may be needed, but this lowers the CO2 conversion and CO/H2 selectivity. Based on these results, it is discussed that there can be minimum steam supply sufficient for guaranteeing both low electrochemical resistance and high gas productivity.

  12. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO2 reforming of methane

    KAUST Repository

    Biausque, Gregory

    2015-09-24

    Embodiments of the present disclosure provide for NiPt nanoparticles, compositions and supports including NiPt nanoparticles, methods of making NiPt nanoparticles, methods of supporting NiPt nanoparticles, methods of using NiPt nanoparticles, and the like.

  13. Síntese e caracterização de perovskitas LaNi(1-xCo xO3 como precursores de catalisadores para a conversão do metano a gás de síntese pela reforma com CO2 Preparation and characterization of LaNi(1-xCo xO3 perovskites as catalyst precursors for synthesis gas generation by CO2 reforming of methane

    Directory of Open Access Journals (Sweden)

    Sania Maria de Lima

    2007-04-01

    Full Text Available LaNiO3 perovskite was modified by partial substitution of nickel by cobalt in order to increase the stability and resistance to carbon deposition during the methane CO2 reforming. The results showed that a suitable combination of precipitation and calcination steps resulted in oxides with the desired structure and with important properties for application in heterogeneous catalysis. The partial substitution of Ni by Co resulted in lower rates of conversion of both the reactants, but the catalyst stability was highly increased. The LaNi0.3Co0.7O3 catalyst, calcined at 800 ºC, was the most active under the reaction conditions.

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

    Directory of Open Access Journals (Sweden)

    Chubin Wan

    2017-02-01

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

  15. 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

  16. Performance of polyethylene based radiation grafted anion exchange membrane with polystyrene-b-poly (ethylene/butylene)-b-polystyrene based ionomer using NiCo2O4 catalyst for water electrolysis

    Science.gov (United States)

    Gupta, Gaurav; Scott, Keith; Mamlouk, Mohamed

    2018-01-01

    A soluble anion exchange ionomer with high OH- ion conductivity comparable to that of H+ conductivity of Nafion is synthesised by chloromethylation of polystyrene-b-poly (ethylene/butylene)-b-polystyrene (SEBS) and used with NiCo2O4 electro-catalyst for water electrolysis. The ionomer has an ion exchange capacity of 1.9 mmol g-1 and ionic conductivity of 0.14 S cm-2 at 50 °C. The cell voltage at 20 °C at 100 mA cm-2 is 1.77 and 1.72 V in, 0.1 and 1.0 M NaOH, respectively, for an optimum loading of 10 mg cm-2 NiCo2O4. At 10 mg cm-2 NiCo2O4 electrolyser cell performance is at least equal to or superior to that of IrO2 at 2 mg cm-2 with excellent stability over 1 h. When the catalyst is sprayed on the GDL instead of CCM, the performance is further improved to 1.65 V at 100 mA cm-2 at 60 °C & 0.1 M KOH. The limited AEM electrolyser performance when operating with deionised water in comparison to PEM and alkaline electrolyser arises from the sluggish OER in the AEM environment equivalent to pH of 11.5 and the two orders of magnitude lower HER activity with respect to acid medium combined with the high Tafel slope of 120 mV dec-1.

  17. In-situ growing NiCo2O4 nanoplatelets on carbon cloth as binder-free catalyst air-cathode for high-performance microbial fuel cells

    International Nuclear Information System (INIS)

    Cao, Chun; Wei, Liling; Wang, Gang; Shen, Jianquan

    2017-01-01

    Highlights: • NiCo 2 O 4 nanoplatelets were in-situ growing on carbon cloth as ORR catalyst in biofuel cells. • Binder-free cathode with the lower internal resistance. • Binder-free cathode was low-cost. • NiCo 2 O 4 -CFC shows better power generation performance than Pt/C. - Abstract: Air-cathode microbial fuel cells (MFCs) was one of most promising sustainable new energy device as well as an advanced sewage treatment technology, and thoroughly studies have been devoted to lower its cost and enhance its power generation. Herein, a binder-free and low-cost catalyst air-cathode was fabricated by in-situ electro-deposition of NiCo 2 O 4 nanoplatelets on carbon cloth, followed by feasible calcinations. The catalytic activity of catalyst air-cathode was optimized by varying the deposition time. And the optimal air-cathode was installed in real MFCs and exhibited distinct maximum out-put power density (645 ± 6 mW m −2 ), which was 12.96% higher than commercial Pt/C (571 ± 11 mW m −2 ). Noted that its remarkable electricity generation performance in MFCs should absolutely attributed to the well catalytic activity for oxygen reduction reaction, and more likely ascribed to its low internal resistance since binder-free catalyst air-cathode can facilitate the electron/charge transfer process. Therefore, it was an efficient strategy to improve the electricity generation performance of MFCs by using this binder-free catalyst air-cathode, which was also potential for application in many other electrochemical devices.

  18. Raman spectroscopy of DNA-metal complexes. II. The thermal denaturation of DNA in the presence of Sr2+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+.

    OpenAIRE

    Duguid, J G; Bloomfield, V A; Benevides, J M; Thomas, G J

    1995-01-01

    Differential scanning calorimetry, laser Raman spectroscopy, optical densitometry, and pH potentiometry have been used to investigate DNA melting profiles in the presence of the chloride salts of Ba2+, Sr2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+. Metal-DNA interactions have been observed for the molar ratio [M2+]/[PO2-] = 0.6 in aqueous solutions containing 5% by weight of 160 bp mononucleosomal calf thymus DNA. All of the alkaline earth metals, plus Mn2+, elevate the melting temperature of ...

  19. CO2 sequestration

    International Nuclear Information System (INIS)

    Favre, E.; Jammes, L.; Guyot, F.; Prinzhofer, A.; Le Thiez, P.

    2009-01-01

    This document presents the summary of a conference-debate held at the Academie des Sciences (Paris, France) on the topic of CO 2 sequestration. Five papers are reviewed: problems and solutions for the CO 2 sequestration; observation and surveillance of reservoirs; genesis of carbonates and geological storage of CO 2 ; CO 2 sequestration in volcanic and ultra-basic rocks; CO 2 sequestration, transport and geological storage: scientific and economical perspectives

  20. Morphology Effect on Enhanced Li+-Ion Storage Performance for Ni2+/3+ and/or Co2+/3+ Doped LiMnPO4 Cathode Nanoparticles

    Directory of Open Access Journals (Sweden)

    Young Jun Yun

    2015-01-01

    Full Text Available The electrochemical performance of Li(Mn, MPO4 (M = Co2+/3+, Ni2+/3+ was investigated with regard to the particle morphology. Within a controlled chemical composition, Li(Mn0.92Co0.04Ni0.04PO4, the resultant cathode exhibited somewhat spherical-shaped nanocrystalline particles and enhanced Li+-ion storage, which was even better than the undoped LiMnPO4, up to 16% in discharge capacity at 0.05 C. The outstanding electrochemical performance is attributed to the well-dispersed spherical-shaped particle morphology, which allows the fast Li+-ion migration during the electrochemical lithiation/delithiation process, especially at high current density.

  1. FY 1996 annual report of investigation on biological fixation of carbon dioxide. 2; 1996 nendo seibutsuteki CO2 kotei ni kansuru chosa hokokusho. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Various kinds of biological fixation processes of CO2 were evaluated from the various viewpoints. Afforestation of tropical and temperate areas, greening of desert, biomass energy production in these areas by energy plantation, coastal mangrove plantation, fertilization with nitrogen and phosphate to outer ocean and coastal, upwelling zone fertilization with iron, and coral reef expansion combined with OTEC (ocean thermal energy conversion) were comparatively investigated as the selected measures. As a result, the cost of CO2 fixation by cultivation of sea weed and plankton was much higher than that of afforestation. The iron fertilization method which was considered to be one of the high CO2 reduction potentials might be economical. However, its effect could not be quantitatively evaluated. The afforestation of tropical and temperate areas seemed to be most feasible in a short term from the viewpoints of economy and environment. It was suggested that the establishment of a systematic water management technology could make greening and afforestation of desert. 76 refs., 27 figs., 28 tabs.

  2. Ni-based electrocatalyst for water oxidation developed In-situ in a HCO3 -/CO2 system at near-neutral pH

    KAUST Repository

    Joya, Khurram Saleem

    2014-03-10

    Electrochemically generated NiOx nanoworms from a neutral bicarbonate system split water into dioxygen and protons with tremendous efficiency and stability. The NiOx electrocatalyst follows a pH-potential dependence, revealing a PCET (proton coupled electron transfer) mechanism of one electron and one proton oxidation. It does not require proton abstracting phosphate or borate buffers for electrogeneration and catalysis, and shows promising activity for anodic oxidation of water in phosphate, borate, and carbonate buffers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Sono-synthesis and characterization of bimetallic Ni-Co/Al2O3-MgO nanocatalyst: Effects of metal content on catalytic properties and activity for hydrogen production via CO2 reforming of CH4.

    Science.gov (United States)

    Abdollahifar, Mozaffar; Haghighi, Mohammad; Babaluo, Ali Akbar; Talkhoncheh, Saeed Khajeh

    2016-07-01

    Sono-dispersion of Ni, Co and Ni-Co over Al2O3-MgO with Al/Mg ratio of 1.5 was prepared and tested for dry reforming of methane. The samples were characterized by XRD, FESEM, PSD, EDX, TEM, BET and FTIR analyses. In order to assess the effect of ultrasound irradiation, Ni-Co/Al2O3-MgO with Co content of 8% prepared via sonochemistry and impregnation methods. The sono-synthesized sample showed better textural properties and higher activity than that of impregnated one. Comparison of XRD patterns indicated that the NiO peaks became broader by increasing Co content over the support. The FESEM images displayed the particles are small and well-dispersed as a result of sonochemistry method. Also, EDX analysis demonstrated better dispersion of Ni and Co as a result of sonochemistry method in confirmation of XRD analysis. The sono-synthesized Ni-Co/Al2O3-MgO as a superior nanocatalyst with Co content of 3% illustrates much higher conversions (97.5% and 99% for CH4 and CO2 at 850 °C), yields (94% and 96% for H2 and CO at 850 °C) and 0.97 of H2/CO molar ratio in all samples using an equimolar feed ratio at 850 °C. During the 1200 min stability test, H2/CO molar ratio remained constant for the superior nanocatalyst. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. SYNGAS PRODUCTION FROM CO2-REFORMING OF CH4 OVER SOL-GEL SYNTHESIZED Ni-Co/Al2O3-MgO-ZrO2 NANOCATALYST: EFFECT OF ZrO2 PRECURSOR ON CATALYST PROPERTIES AND PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Seyed Mehdi Sajjadi

    2015-05-01

    Full Text Available Ni-Co/Al2O3-MgO-ZrO2 nanocatalyst with utilization of two different zirconia precursors, namely, zirconyl nitrate hydrate (ZNH and zirconyl nitrate solution (ZNS, was synthesized via the sol-gel method. The physiochemical properties of nanocatalysts were characterized by XRD, FESEM, EDX, BET and FTIR analyses and employed for syngas production from CO2-reforming of CH4. XRD patterns, exhibiting proper crystalline structure and homogeneous dispersion of active phase for the nanocatalyst ZNS precursor employed (NCAMZ-ZNS. FESEM and BET results of NCAMZ-ZNS presented more uniform morphology and smaller particle size and consequently higher surface areas. In addition, average particle size of NCAMZ-ZNS was 15.7 nm, which is close to the critical size for Ni-Co catalysts to avoid carbon formation. Moreover, FESEM analysis indicated both prepared samples were nanoscale. EDX analysis confirmed the existence of various elements used and also supported the statements made in the XRD and FESEM analyses regarding dispersion. Based on the excellent physiochemical properties, NCAMZ-ZNS exhibited the best reactant conversion across all of the evaluated temperatures, e.g. CH4 and CO2 conversions were 97.2 and 99% at 850 ºC, respectively. Furthermore, NCAMZ-ZNS demonstrated a stable yield with H2/CO close to unit value during the 1440 min stability test.

  5. Syngas production from CO2-reforming of CH4 over sol-gel synthesized Ni-Co/Al2O3-MgOZrO2 nanocatalyst: effect of ZrO2 precursor on catalyst properties and performance

    International Nuclear Information System (INIS)

    Sajjadi, Seyed Mehdi; Haghighi, Mohammad; Rahmani, Farhad

    2015-01-01

    Ni-Co/Al 2 O 3 -MgO-ZrO 2 nanocatalyst with utilization of two different zirconia precursors, namely, zirconyl nitrate hydrate (ZNH) and zirconyl nitrate solution (ZNS), was synthesized via the sol-gel method. The physiochemical properties of nanocatalysts were characterized by XRD, FESEM, EDX, BET and FTIR analyses and employed for syngas production from CO 2 -reforming of CH 4 . XRD patterns, exhibiting proper crystalline structure and homogeneous dispersion of active phase for the nanocatalyst ZNS precursor employed (NCAMZ-ZNS). FESEM and BET results of NCAMZ-ZNS presented more uniform morphology and smaller particle size and consequently higher surface areas. In addition, average particle size of NCAMZ-ZNS was 15.7 nm, which is close to the critical size for Ni-Co catalysts to avoid carbon formation. Moreover, FESEM analysis indicated both prepared samples were nanoscale. EDX analysis confirmed the existence of various elements used and also supported the statements made in the XRD and FESEM analyses regarding dispersion. Based on the excellent physiochemical properties, NCAMZ-ZNS exhibited the best reactant conversion across all of the evaluated temperatures, e.g. CH 4 and CO 2 conversions were 97.2 and 99% at 850 °C, respectively. Furthermore, NCAMZZNS demonstrated a stable yield with H 2 /CO close to unit value during the 1440 min stability test. (author)

  6. The role of a low-energy–density re-scan in fabricating crack-free Al85Ni5Y6Co2Fe2 bulk metallic glass composites via selective laser melting

    International Nuclear Information System (INIS)

    Li, X.P.; Kang, C.W.; Huang, H.; Sercombe, T.B.

    2014-01-01

    Highlights: • We proposed a re-scan strategy to prevent crack propagation in SLM. • The re-scan should be carried out at a low laser energy density. • The underlying mechanism is through reduction and relief of residual stresses. • Lowered temperature gradient and superplasticity account for reduction of stress. • For the first time, a crack-free BMGCs gear with a large size was produced. - Abstract: In this paper, we have investigated the use of a re-scanning strategy to prevent propagation of macro-cracks during the selective laser melting of an Al 85 Ni 5 Y 6 Co 2 Fe 2 bulk metallic glass composites (BMGCs). These cracks form as a result of the high residual stress caused by the rapid heating and cooling of the material by the laser beam. Unlike crystalline materials, the BMGCs possess a supercooled liquid region in which the residual stress can be relieved by plastic flow. We show that by using a high power initial scan (designed to melt the material) followed by a lower power re-scan (for stress relief) cracking can be prevented. Using this approach, crack-free Al 85 Ni 5 Y 6 Co 2 Fe 2 BMGCs components have been fabricated, including a gear with a diameter ∼25 mm and height ∼10 mm

  7. Kinetics of CO/CO2 and H2/H2O reactions at Ni-based and ceria-based solid-oxide-cell electrodes

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2015-01-01

    The solid oxide electrochemical cell (SOC) is an energy conversion technology that can be operated reversibly, to efficiently convert chemical fuels to electricity (fuel cell mode) as well as to store electricity as chemical fuels (electrolysis mode). The SOC fuel-electrode carries out......, a composite of nickel and yttria/scandia stabilized zirconia (Ni–SZ). Ni–SZ is known to be more active for H2/H2O than for CO/CO2 reactions, but the reported relative activity varies widely. Here we compare AC impedance and DC current–overpotential data measured in the two gas environments for several...

  8. CO2 blood test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003469.htm CO2 blood test To use the sharing features on this page, ... a substance called bicarbonate (HCO3-). Therefore, the CO2 blood test is really a measure of your blood bicarbonate ...

  9. La0.8Sr0.2Co0.8Ni0.2O3-δ impregnated oxygen electrode for H2O/CO2 co-electrolysis in solid oxide electrolysis cells

    Science.gov (United States)

    Zheng, Haoyu; Tian, Yunfeng; Zhang, Lingling; Chi, Bo; Pu, Jian; Jian, Li

    2018-04-01

    High-temperature H2O/CO2 co-electrolysis through reversible solid oxide electrolysis cell (SOEC) provides potentially a feasible and eco-friendly way to convert electrical energy into chemicals stored in syngas. In this work, La0.8Sr0.2Co0.8Ni0.2O3-δ (LSCN) impregnated Gd0.1Ce0.9O1.95 (GDC)-(La0.8Sr0.2)0.95MnO3-δ (LSM) composite oxygen electrode is studied as high-performance electrode for H2O/CO2 co-electrolysis. The LSCN impregnated cell exhibits competitive performance with the peak power density of 1057 mW cm-2 at 800 °C in solid oxide fuel cell (SOFC) mode; in co-electrolysis mode, the current density can reach 1.60 A cm-2 at 1.5 V at 800 °C with H2O/CO2 ratio of 2/1. With LSCN nanoparticles dispersed on the surface of GDC-LSM to maximize the reaction active sites, the LSCN impregnated cell shows significant enhanced electrochemical performance at both SOEC and SOFC modes. The influence of feed gas composition (H2O-H2-CO2) and operating voltages on the performance of co-electrolysis are discussed in detail. The cell shows a very stable performance without obvious degradation for more than 100 h. Post-test characterization is analyzed in detail by multiple measurements.

  10. Theoretical Insights into the Nature of Nickel-Carbon Dioxide Interactions in Ni(PH3)2(eta2-CO2)

    Czech Academy of Sciences Publication Activity Database

    Kegl, T.; Ponec, Robert; Kollar, L.

    2011-01-01

    Roč. 115, č. 45 (2011), s. 12463-12473 ISSN 1089-5639 R&D Projects: GA ČR GA203/09/0118 Grant - others:HSRF(HU) OTKA NK 71906; HSRF(HU) OTKA-NKTH CK 78553; RTI(HU) SROP-4.2.2/08/1/2008-2011 Institutional research plan: CEZ:AV0Z40720504 Keywords : carbon dioxide coordination to Ni * analysis of bonding interactions * density functional methods Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.946, year: 2011

  11. Biomass derived Ni(OH)2@porous carbon/sulfur composites synthesized by a novel sulfur impregnation strategy based on supercritical CO2 technology for advanced Li-S batteries

    Science.gov (United States)

    Xia, Yang; Zhong, Haoyue; Fang, Ruyi; Liang, Chu; Xiao, Zhen; Huang, Hui; Gan, Yongping; Zhang, Jun; Tao, Xinyong; Zhang, Wenkui

    2018-02-01

    The rational design and controllable synthesis of sulfur cathode with high sulfur content, superior structural stability and fascinating electrochemical properties is a vital step to realize the large-scale application of rechargeable lithium-sulfur (Li-S) batteries. However, the electric insulation of elemental sulfur and the high solubility of lithium polysulfides are two intractable obstacles to hinder the success of Li-S batteries. In order to overcome aforementioned issues, a novel strategy combined supercritical CO2 fluid technology and biotemplating method is developed to fabricate Ni(OH)2 modified porous carbon microspheres as sulfur hosts to ameliorate the electronic conductive of sulfur and enhance simultaneously the physical and chemical absorptions of polysulfides. This elaborately designed Ni(OH)2@PYC/S composite cathode exhibits high reversible discharge capacity (1335 mAh g-1 at 0.1 C), remarkable cyclic stability (602 mAh g-1 after 200 cycles at 0.2 C) and superior rate capability, which is much better than its PYC/S counterpart. These results clearly demonstrate that the advanced porous carbon with good conductivity and the polar Ni(OH)2 coating layer with strong trapping ability of polysulfides are responsible for the enhanced electrochemical performance.

  12. Wrong Forms of some Yorùbá Personal Names: Some Phonological and Sociolinguistic Implications

    Directory of Open Access Journals (Sweden)

    Reuben Olúwáfẹ́mi Ìkọ̀tún

    2014-12-01

    Full Text Available In this study, we examine the wrong forms of some Yorùbá sentences that have become personal names through compounding. The data were extracted from the Joint Admissions and Matriculation Board (JAMB lists of candidates that were considered for admission into three Nigerian Universities between the 2005 and 2010 academic sessions. The names extracted from that source were compared with names written in the staff lists of the three Universities in Nigeria. The wrongly written names were recorded on tapes and some native speakers were asked to listen to them to determine their correctness. We argue that wrong forms of some Yorùbá sentential/personal names are common occurrences and establish that they are traceable to the freedom granted by Yorùbá orthography developers. We also argue that, the confusion that results from the different spelling forms of some Yorùbá personal names is seriously observable in social interactions, labour market, schools or Colleges of Education/Universities, Embassies and Nigerian civil service both Federal and State and that court affidavits become imperative to authenticate or reconcile both the wrong and the correct forms for the purposes of admissions, appointments and overseas travelling documents. Similarly, we show that the position of the Yorùbá orthography developers has resulted in a loss of the actual pronunciation of some Yorùbá personal names which has severe implications for the semantic contents of the names as well as implications for the rich religious, cultural and philosophical heritage of the Yorùbá people.

  13. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  14. Synthesis, characterization and application of some nanosized mixed metal oxides as high heat resistant pigments: Ca2CuO3, Ca3Co2O6, and NiSb2O6

    International Nuclear Information System (INIS)

    Fouad, Osama A.; Hassan, Ali M.; Abd El-Wahab, Hamada; Mohy Eldin, Adel; Naser, Abdel-Rahman M.; Wahba, Osama A.G.

    2012-01-01

    Graphical abstract: Mixed metal oxides have been widely used for various applications such as pigments in coatings. This work presents synthesis of a group of mixed metal oxides (Ca 2 CuO 3 , Ca 3 Co 2 O 6 and NiSb 2 O 6 ) by employing two simple synthesis techniques namely; co-precipitation and solid-state calcinations methods. The prepared pigments were characterized using X-ray diffraction, infra-red spectroscopy, and scanning electron microscopy. The obtained XRD results showed that single phase double oxide compounds were the main components in each case. SEM images showed the formation of either platelet or well defined polyhedron crystal structures based on the type of the double oxide and the preparation method. The physical, mechanical, heat and corrosion resistance of dry paint films were also examined. The obtained results revealed that the prepared calcium based pigments showed excellent heat and corrosion resistance and that with copper oxide is the best in performance among others. Highlights: ► Synthesis of single phase mixed metal oxide pigments by two simple methods; co-precipitation and solid state reaction. ► The painted films using the prepared pigments showed high heat resistant up to 600 °C. ► The painted films over mild steel sheets showed high corrosion resistant characteristics in 5% NaCl salt solution for 500 h. - Abstract: Mixed metal oxides have been widely used for various applications such as pigments in coatings. This work presents synthesis of a group of mixed metal oxides (Ca 2 CuO 3, Ca 3 Co 2 O 6 and NiSb 2 O 6 ) by employing two simple synthesis techniques namely; co-precipitation and solid-state calcination method. The prepared pigments were characterized using X-ray diffraction, infra-red spectroscopy, and scanning electron microscopy. The obtained XRD results showed that single phase double oxide compounds were the main components in each case. SEM images showed the formation of either platelet or well defined

  15. CO2 chemical valorization

    International Nuclear Information System (INIS)

    Kerlero De Rosbo, Guillaume; Rakotojaona, Loic; Bucy, Jacques de; Clodic, Denis; Roger, Anne-Cecile; El Khamlichi, Aicha; Thybaud, Nathalie; Oeser, Christian; Forti, Laurent; Gimenez, Michel; Savary, David; Amouroux, Jacques

    2014-07-01

    Facing global warming, different technological solutions exist to tackle carbon dioxide (CO 2 ) emissions. Some inevitable short term emissions can be captured so as to avoid direct emissions into the atmosphere. This CO 2 must then be managed and geological storage seems to currently be the only way of dealing with the large volumes involved. However, this solution faces major economic profitability and societal acceptance challenges. In this context, alternative pathways consisting in using CO 2 instead of storing it do exist and are generating growing interest. This study ordered by the French Environment and Energy Management Agency (ADEME), aims at taking stock of the different technologies used for the chemical conversion of CO 2 in order to have a better understanding of their development potential by 2030, of the conditions in which they could be competitive and of the main actions to be implemented in France to foster their emergence. To do this, the study was broken down into two main areas of focus: The review and characterization of the main CO 2 chemical conversion routes for the synthesis of basic chemical products, energy products and inert materials. This review includes a presentation of the main principles underpinning the studied routes, a preliminary assessment of their performances, advantages and drawbacks, a list of the main R and D projects underway, a focus on emblematic projects as well as a brief analysis of the markets for the main products produced. Based on these elements, 3 routes were selected from among the most promising by 2030 for an in-depth modelling and assessment of their energy, environmental and economic performances. The study shows that the processes modelled do have favorable CO 2 balances (from 1 to 4 t-CO 2 /t-product) and effectively constitute solutions to reduce CO 2 emissions, despite limited volumes of CO 2 in question. Moreover, the profitability of certain solutions will remain difficult to reach, even with an

  16. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  17. CO2NNIE

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2015-01-01

    We propose a system for calculating the personalized annual fuel consumption and CO2 emissions from transportation. The system, named CO2NNIE, estimates the fuel consumption on the fastest route between the frequent destinations of the user. The travel time and fuel consumption estimated are based...... on 3.8 billion GPS records from 16 thousand cars and 198 million records from 218 cars annotated with fuel consumption data, respectively. The fuel consumption estimates from the system are validated using fuel-pump data. We find that estimates have good accuracy, i.e., are generally within 10......% of the actual fuel consumption (4.6% deviation on average). We conclude, that the system provides new detailed information on CO2 emissions and fuel consumption for any make and model....

  18. CO2-strategier

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2008-01-01

    I 2007 henvendte Lyngby-Taarbæk kommunens Agenda 21 koordinator sig til Videnskabsbutikken og spurgte om der var interesse for at samarbejde om CO2-strategier. Da Videnskabsbutikken DTU er en åben dør til DTU for borgerne og deres organisationer, foreslog Videnskabsbutikken DTU at Danmarks...

  19. CO2-neutral fuels

    Science.gov (United States)

    Goede, A. P. H.

    2015-08-01

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

  20. 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

  1. Características elétricas do sistema varistor ZnO.Bi2O3.Co2O 3.MnO2 dopado com Ni2O3 Electrical characteristics of Ni2O3- doped ZnO. Bi2O3.Co2O3.MnO2 varistor systems

    Directory of Open Access Journals (Sweden)

    Ana Cristina F. M. Costa

    1998-08-01

    Full Text Available Este trabalho tem como objetivo analisar o efeito do óxido de níquel sobre as propriedades elétricas do sistema varistor ZnO.Bi2O3.Co2O3.MnO2 . Os sistemas foram sinterizados a 1100ºC, 1150 ºC, 1200 ºC e 1250 ºC, por 1 hora. A caracterização elétrica foi feita por meio de medidas de densidade de corrente em função do campo elétrico aplicado. A caracterização microestrutural foi obtida por meio de difração de raios X e microscopia eletrônica de varredura. As melhores propriedades elétricas foram obtidas para o sistema contendo 1,0% em mol de óxido de níquel, sinterizado a 1100 oC. A elevação da temperatura de sinterização causou uma redução nas propriedades elétricas, provavelmente devido a formação de uma microestrutura mais heterogênea.The effect of nickel oxide addition on the electrical properties of the ZnO. Bi2O3. Co2O3. MnO2 varistor system was investigated. This system was sintered at 1100 ºC, 1150 ºC, 1200 ºC and 1250 ºC for one hour and electrical measurements (current density as a function of the applied electrical field were carried out. The microstructural analyses were performed by scanning electron microscopy and X-ray diffraction. The best electrical properties were obtained for the system containing 1.0 mol% of nickel oxide, and sintered at 1100 ºC. A degradation in the electrical properties with increasing sintering temperature has been observed, probably due to an increase in the microstructural heterogeneity.

  2. BTX production by in-situ contact reforming of low-temperature tar from coal with zeolite-derived catalysts; Zeolite kei shokubai wo mochiita sekitan teion tar no sesshoku kaishitsu ni yoru BTX no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, T.; Fuda, K.; Murakami, K.; Kyo, M.; Hosoya, S.; Kobayashi, S. [Akita University, Akita (Japan). Mining College

    1996-10-28

    On BTX production process from low-temperature tar obtained by pyrolysis of coal, the effect of exchanged metallic species and reaction temperature were studied using metallic ion-exchanged Y-zeolite as catalyst. In experiment, three kinds of coals with different produced tar structures such as Taiheiyo and PSOC-830 sub-bituminous coals and Loy Yang brown coal were used. Y-zeolite ion-exchanged with metal chloride aqueous solution was used as catalyst. Zn{sup 2+}, Ni{sup 2+} and In{sup 3+} were used as metal ions to be exchanged. The experiment was conducted by heating a pyrolysis section up to 600{degree}C for one hour after preheating a contact reforming section up to a certain proper temperature. As a result, the Ni system catalyst was effective for BTX production from aromatic-abundant tar, while the Zn system one from lower aromatic tar. In general, relatively high yields of toluene and xylene were obtained at lower temperature, while those of benzene at higher temperature. 4 figs., 1 tab.

  3. FY 1998 annual report on the CO{sub 2} reduction by 30 manufacturing companies (plants) through energy conservation. Thailand; Seizogyo 30 sha (kojo) no sho energy ni yoru CO{sub 2} haishutsuryo sakugen 1998 nendo chosa hokokusho. Taikoku

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This project is aimed at energy-saving diagnosis of 30 energy-intensive manufacturing plants in Thailand, to draw the project plans and clarify, e.g., greenhouse effect gas reduction and cost-effectiveness effects, on the basis of transferring and applying the energy management and energy-saving equipment technologies now being used by the manufacturing sector in Japan. The 30 plants analyzed are 6 metal-related plants, 3 non-ferrous plants, 5 chemical plants, 6 ceramics plant, 4 textile plants, 4 food processing plants and 2 pulp plants. Two or more feasible energy-saving measures are studied for each plant. A total of 178 improvement measures (approximately 6 on the average for each plant) are identified as the ones related to energy-saving and operation controlling techniques. These measures could reduce CO2 emissions by 145,000 t/y from 1,370,000 t/y released from the 30 plants. The measures of high cost-effectiveness are (use of an appropriate pressure for air compressors) and (resting of transformers on non-working days). (NEDO)

  4. Raman spectroscopy of DNA-metal complexes. II. The thermal denaturation of DNA in the presence of Sr2+, Ba2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+.

    Science.gov (United States)

    Duguid, J G; Bloomfield, V A; Benevides, J M; Thomas, G J

    1995-12-01

    Differential scanning calorimetry, laser Raman spectroscopy, optical densitometry, and pH potentiometry have been used to investigate DNA melting profiles in the presence of the chloride salts of Ba2+, Sr2+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, and Cd2+. Metal-DNA interactions have been observed for the molar ratio [M2+]/[PO2-] = 0.6 in aqueous solutions containing 5% by weight of 160 bp mononucleosomal calf thymus DNA. All of the alkaline earth metals, plus Mn2+, elevate the melting temperature of DNA (Tm > 75.5 degrees C), whereas the transition metals Co2+, Ni2+, and Cd2+ lower Tm. Calorimetric (delta Hcal) and van't Hoff (delta HVH) enthalpies of melting range from 6.2-8.7 kcal/mol bp and 75.6-188.6 kcal/mol cooperative unit, respectively, and entropies from 17.5 to 24.7 cal/K mol bp. The average number of base pairs in a cooperative melting unit () varied from 11.3 to 28.1. No dichotomy was observed between alkaline earth and transition DNA-metal complexes for any of the thermodynamic parameters other than their effects on Tm. These results complement Raman difference spectra, which reveal decreases in backbone order, base unstacking, distortion of glycosyl torsion angles, and rupture of hydrogen bonds, which occur after thermal denaturation. Raman difference spectroscopy shows that transition metals interact with the N7 atom of guanine in duplex DNA. A broader range of interaction sites with single-stranded DNA includes ionic phosphates, the N1 and N7 atoms of purines, and the N3 atom of pyrimidines. For alkaline earth metals, very little interaction was observed with duplex DNA, whereas spectra of single-stranded complexes are very similar to those of melted DNA without metal. However, difference spectra reveal some metal-specific perturbations at 1092 cm-1 (nPO2-), 1258 cm-1 (dC, dA), and 1668 cm-1 (nC==O, dNH2 dT, dG, dC). Increased spectral intensity could also be observed near 1335 cm-1 (dA, dG) for CaDNA. Optical densitometry, employed to detect DNA

  5. FY 2000 report on the results of the R and D of the prediction technology for environmental effects of CO2 ocean sequestration. Ocean survey and development of the assessment technology for capacity of CO2 sequestration; 2000 nendo nisanka tanso no kaiyo kakuri ni tomonau kankyo eikyo yosoku gijutsu kenkyu kaihatsu seika hokokusho. Kaiyo chosa oyobi CO2 kakuri noryoku hyoka gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Assuming the dissolution/sequestration of CO2 at the medium-depth sea area around Japan (depth: 1,000-2,000m), the development was being proceeded with of the assessment technology for capacity of CO2 ocean sequestration and the prediction technology of environmental effects at the point of CO2 discharge. In FY 2000, conducted were the ocean survey and the development of assessment technology for CO2 sequestration capacity. In the investigational study, the following three were carried out: 1) survey/observation of the flow field on the line of 165 degrees of east longitude, and acquisition of various data such as the distribution of carbonic acid base substances and the speed of carbon transport; 2) study of the amount of existence of organisms and kind/composition of the medium-depth plankton at the typical observation points; 3) test/experiment actually conducted in the sea area for the experimental equipment for CaCO3 dissolution experimental equipment for studying interactions between the CO2 and CaCO3 dissolved into the medium-depth sea. As to the development of the assessment technology, carried out were the heightening of accuracy of medium-depth ocean circulation models using the inverse method already developed and the estimation of the flow field using the observation data. At the same time, the estimation of the flow field, etc. were conducted using large circulation ocean models. (NEDO)

  6. Design of environment-friendly and next generation-type conversion system for unused carbon resources by developing highly functional materials; Kokino zairyo kaihatsu ni yoru kankyo chowagata jisedai miriyo tanso shigen tenkan system no kochiku

    Energy Technology Data Exchange (ETDEWEB)

    Wakabayashi, K.; Morooka, S.; Arai, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Sakanishi, K. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1997-02-01

    Studies are conducted for the development of now-unused kinds of fossil carbon resources, such as low rank coal and heavy gravity crude oil, into higher-value liquid fuel. In the preliminary treatment process, the fossil carbon resources are dried by use of supercritical carbon dioxide, when it is found that the resources are disintegrated and water is desorbed. In a low rank coal liquefaction process using the NiMo/KB (Kefjen Black) catalyst, more than 60% is converted into oil, which rate is improved by use of the dual-temperature liquefaction process. This catalyst may be recovered by separation utilizing specific gravity difference. As a low temperature gasification catalyst, the alkaline carbonate-carried carbon catalyst is very quick at the initial stage of reaction. The perovskite-carried alkaline carbonate catalyst is high in carbon oxidizing/activating efficiency at low temperatures. The silica film deposited on an alumina-coated support tube is excellent in selectivity and speed as a hydrogen separating film, and a carbonized polyimide film as a carbon dioxide separating film. For the supercritical phase adsorption/separation of chemicals not to be distilled easily, the NaY-type zeolite functions effectively. Pd/ZrO2 serving as a carbon monoxide conversion catalyst enables the recovery of more MeOH when Pd grains are smaller in diameter.

  7. Fiscal 1997 survey report on the jointly executed/promoted basic survey project (the jointly executed activity Japan Program). Feasibility survey for CO2 reduction by deregulating heavy traffic at specified crossings in Bangkok, Thailand; 1997 nendo chosa hokokusho (kyodo jisshi suishin kiso chosa jigyo (kyodo jisshi katsudo Japan program)). Taikoku Bangkok no tokutei kosaten ni okeru kotsu jutai kanwa ni yoru CO2 sakugen kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The monetary crisis in Thailand with the baht drop in July 1997 as a beginning rapidly worsened the Thai economy. With it, the number of automobiles sold sharply declined, and automobile manufacturers were also heavily damaged as seen in the temporary discontinued production, etc. Under such economic situation, a discussion was made on execution of the project with the Thai Automotive Industry Association (TAIA), a partner at the Thai side. As a result, agreement was made on the positioning of the project, role sharing, and selection of measures against heavy traffic as follows: Japan Automobile Manufacturers Association (JAMA) conducts a feasibility study, proposal of a construction plan and confirmation of effects, and bears the costs. TAIA bears the execution and cost of construction (Due to the worsened Thai economy, JAMA paid almost all the construction expenses). In the light of the economic situation in Thailand, `improvement of the signal control system` was selected as an execution candidate, which has the highest cost effect among the measures against heavy traffic. In the future, the application, registration and execution are done for joint activities for the project. 49 figs., 59 tabs.

  8. CO2 laser development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The research and development programs on high-energy, short-pulse CO 2 lasers were begun at LASL in 1969. Three large systems are now either operating or are being installed. The Single-Beam System (SBS), a four-stage prototype, was designed in 1971 and has been in operation since 1973 with an output energy of 250 J in a 1-ns pulse with an on-target intensity of 3.5 x 10 14 W/cm 2 . The Dual-Beam System (DBS), now in the final stages of electrical and optical checkout, will provide about ten times more power for two-beam target irradiation experiments. Four such dual-beam modules are being installed in the Laser-Fusion Laboratory to provide an Eight-Beam System (EBS) scheduled for operation at the 5- to 10-TW level in 1977. A fourth system, a 100- to 200-TW CO 2 laser, is being designed for the High-Energy Gas Laser Facility (HEGLF) program

  9. FY 1999 report on the results of the R and D project on the industrial technology for the global environment. R and D of the prediction technology of environmental effects brought by CO2 ocean sequestration (Ocean survey and development of evaluation technology for CO2 sequestration ability); 1999 nendo chikyu kankyo sangyo gijutsu kenkyu kaihatsu jigyo NEDO seika hokokusho. Nisankatanso no kaiyo kakuri ni tomonau kankyo eikyo yosoku gijutsu kenkyu kaihatsu (Kaiyo chosa oyobi CO2 kakuri noryoku hyoka gijutsu no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Assuming the melting and sequestration of CO2 at the intermediate depth of the sea area around Japan, study of evaluation technology of CO2 sequestration ability in ocean was studied, and the FY 1999 results were summed up. In the ocean survey, survey was conducted by ship (No.2 Hakurei-maru) mainly at typical observation points and traverse lines of long. 147 E and long. 155 E. In the survey, the following data were acquired: data on seawater density and chemical tracer, data on release of intermediate-depth/independent buoys, concentration distribution of carbonic acid base substances/nutrient salts/chlorophyll, data on the existing amount of marine organisms and primary production speed measurement experiment, data on experiment on CO2 on-board exposure to organisms in the intermediate depth of ocean, etc. In the measurement/analysis of the sediment particle flux amount, sediment traps were installed/recovered. Further, for the purpose of measuring the neutralizing effect of calcium carbonate, operation test on CaCO{sub 3} melting experimental equipment was conducted in the actual sea area. In the development of a model for evaluation of CO2 sequestration ability, carried out were the improvement of the model using the inverse method, study of the estimated accuracy using the ocean observation data, etc. (NEDO)

  10. Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbol-lylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

    Directory of Open Access Journals (Sweden)

    E. MAKRLÍK

    2008-12-01

    Full Text Available The exchange extraction constants corresponding to the general equilibrium M2+(aq + SrL2+(nb D ML2+ (nb + Sr2+ (aq occurring in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase were evaluated from extraction experiments and -activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

  11. India Co2 Emissions

    Science.gov (United States)

    Sharan, S.; Diffenbaugh, N. S.

    2010-12-01

    created a balance in between the “developed” and developing countries. If India was producing the same amounts of emissions per capita as the it would have a total of 20 billion metric tons of CO2 emissions annually.

  12. CO2 as a refrigerant

    CERN Document Server

    2014-01-01

    A first edition, the IIR guide “CO2 as a Refrigerant” highlights the application of carbon dioxide in supermarkets, industrial freezers, refrigerated transport, and cold stores as well as ice rinks, chillers, air conditioning systems, data centers and heat pumps. This guide is for design and development engineers needing instruction and inspiration as well as non-technical experts seeking background information on a specific topic. Written by Dr A.B. Pearson, a well-known expert in the field who has considerable experience in the use of CO2 as a refrigerant. Main topics: Thermophysical properties of CO2 – Exposure to CO2, safety precautions – CO2 Plant Design – CO2 applications – Future prospects – Standards and regulations – Bibliography.

  13. Novel layered solid oxide fuel cells with multiple-twinned Ni0.8Co0.2 nanoparticles: the key to thermally independent CO2 utilization and power-chemical cogeneration

    NARCIS (Netherlands)

    Hua, B.; Yan, N.; Li, M.; Zhang, Y.-Q.; Sun, Y.-F.; Li, J.; Etsell, T.; Sarkar, P.; Chuang, K.T.; Luo, J.L.

    2016-01-01

    To energy-efficiently offset our carbon footprint, we herein developed a novel CH4–CO2 dry reforming process to co-produce electricity and CO-concentrated syngas, which takes advantage of the selective oxidation of H2 in high performance proton-conducting solid oxide fuel cells (SOFCs). In these

  14. CO2 interaction with geomaterials.

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, George D. (U.S. Department of Energy, Pittsburgh, PA); Al-Saidi, Wissam A. (University of Pittsburgh, Pittsburgh, PA); Jordan, Kenneth D. (University of Pittsburgh, Pittsburgh, PA); Voora, Vamsee, K. (University of Pittsburgh, Pittsburgh, PA); Romanov, Vyacheslav N. (U.S. Department of Energy, Pittsburgh, PA); Lopano, Christina L (U.S. Department of Energy, Pittsburgh, PA); Myshakin, Eugene M. (URS Corporation, Pittsburgh, PA); Hur, Tae Bong (University of Pittsburgh, Pittsburgh, PA); Warzinski, Robert P. (U.S. Department of Energy, Pittsburgh, PA); Lynn, Ronald J. (URS Corporation, Pittsburgh, PA); Howard, Bret H. (U.S. Department of Energy, Pittsburgh, PA); Cygan, Randall Timothy

    2010-09-01

    This work compares the sorption and swelling processes associated with CO2-coal and CO2-clay interactions. We investigated the mechanisms of interaction related to CO2 adsortion in micropores, intercalation into sub-micropores, dissolution in solid matrix, the role of water, and the associated changes in reservoir permeability, for applications in CO2 sequestration and enhanced coal bed methane recovery. The structural changes caused by CO2 have been investigated. A high-pressure micro-dilatometer was equipped to investigate the effect of CO2 pressure on the thermoplastic properties of coal. Using an identical dilatometer, Rashid Khan (1985) performed experiments with CO2 that revealed a dramatic reduction in the softening temperature of coal when exposed to high-pressure CO2. A set of experiments was designed for -20+45-mesh samples of Argonne Premium Pocahontas No.3 coal, which is similar in proximate and ultimate analysis to the Lower Kittanning seam coal that Khan used in his experiments. No dramatic decrease in coal softening temperature has been observed in high-pressure CO2 that would corroborate the prior work of Khan. Thus, conventional polymer (or 'geopolymer') theories may not be directly applicable to CO2 interaction with coals. Clays are similar to coals in that they represent abundant geomaterials with well-developed microporous structure. We evaluated the CO2 sequestration potential of clays relative to coals and investigated the factors that affect the sorption capacity, rates, and permanence of CO2 trapping. For the geomaterials comparison studies, we used source clay samples from The Clay Minerals Society. Preliminary results showed that expandable clays have CO2 sorption capacities comparable to those of coal. We analyzed sorption isotherms, XRD, DRIFTS (infrared reflectance spectra at non-ambient conditions), and TGA-MS (thermal gravimetric analysis) data to compare the effects of various factors on CO2 trapping. In montmorillonite, CO

  15. Convergent Cenozoic CO2 history

    Science.gov (United States)

    Royer, D. L.; Beerling, D. J.

    2011-12-01

    The quality and quantity of Cenozoic CO2 records have increased significantly in the last decade. Gains in quality have come primarily from a fuller accounting of confounding factors; examples include soil respiration rates in the pedogenic carbonate method, alkalinity and seawater δ11B in the boron method, and cell size in the alkenone phytoplankton method. Previously, variability across Cenozoic CO2 estimates in a given time period sometimes exceeded an order of magnitude, but through these improvements variability has been reduced to a factor of two or less. Further improvements in the record can probably be facilitated by more robust quantification of statistical error, generation of CO2 estimates at single locations from multiple methods, and cross-calibration with Pleistocene ice-core CO2 records (Beerling & Royer, 2011, Nature Geoscience 4: 418-420). An improved Cenozoic CO2 record offers opportunities for better understanding Earth system processes. We provide one example related to climate sensitivity. We find a significant relationship between CO2 radiative forcing and global temperature during the Cenozoic, even after accounting for forcings related to solar evolution and paleogeographic changes. Although the calculations are based on simple assumptions and should be taken as provisional, the mean Cenozoic climate sensitivity (3 °C or higher per CO2 doubling) is similar to or higher than calculations for the present-day (~3 °C per CO2 doubling).

  16. 14CO2 in breath

    International Nuclear Information System (INIS)

    Rabinowitz, J.L.; Lopez-Majano, V.

    1981-01-01

    The diagnosis of metabolic disorders can be made by detecting 14 CO 2 in the breath. This is possible because 14 CO 2 can label any organic compound without any deteriorations in the nature of the compound. This type of analysis is dependable, noninvasive and simple to perform with a scintillation counter. (orig.)

  17. The sequestration of CO2

    International Nuclear Information System (INIS)

    Le Thiez, P.

    2004-01-01

    The reduction of greenhouse gas emissions, especially CO 2 , represents a major technological and societal challenge in the fight against climate change. Among the measures likely to reduce anthropic CO 2 emissions, capture and geological storage holds out promise for the future. (author)

  18. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  19. CO2 Sequestration short course

    Energy Technology Data Exchange (ETDEWEB)

    DePaolo, Donald J. [Lawrence Berkeley National Laboratory; Cole, David R [The Ohio State University; Navrotsky, Alexandra [University of California-Davis; Bourg, Ian C [Lawrence Berkeley National Laboratory

    2014-12-08

    Given the public’s interest and concern over the impact of atmospheric greenhouse gases (GHGs) on global warming and related climate change patterns, the course is a timely discussion of the underlying geochemical and mineralogical processes associated with gas-water-mineral-interactions encountered during geological sequestration of CO2. The geochemical and mineralogical processes encountered in the subsurface during storage of CO2 will play an important role in facilitating the isolation of anthropogenic CO2 in the subsurface for thousands of years, thus moderating rapid increases in concentrations of atmospheric CO2 and mitigating global warming. Successful implementation of a variety of geological sequestration scenarios will be dependent on our ability to accurately predict, monitor and verify the behavior of CO2 in the subsurface. The course was proposed to and accepted by the Mineralogical Society of America (MSA) and The Geochemical Society (GS).

  20. FY 2000 report on the results of the project on the R and D of the global environmental industry technology. R and D of the technology for predicting environmental effects associated with the CO2 ocean sequestration (Development of the technology for predicting environmental effects in the area around the CO2 discharge point and survey for supporting study); 2000 nendo chikyu kankyo sangyo gijutsu kenkyu kaihatsu jigyo. Nisanka tanso no kaiyo kakuri ni tomonau kankyo eikyo yosoku gijutsu kenkyu kaihatsu (CO2 horyuten shuhen'iki no kankyo eikyo yosoku gijutsu no kaihatsu narabini kenkyu shien chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-03-01

    To obtain the technical outlook for CO2 ocean sequestration by CO2 discharge into the intermediate layer, the R and D was conducted of the technology for predicting environmental effects in the area around the CO2 discharge point, and the FY 2000 results were summed up. In the elucidation study of the behavior at the time of discharging liquid CO2, the melting process of CO2 droplets discharged/dispersed into the seawater of the intermediate layer was observed, and the specific phenomenon of hydrate formation in the process of CO2 droplet formation was grasped. As to the technology for sending CO2 into the ocean and diluting it, experimental study was made of CO2 transportation technology from on the sea to the intermediate layer, technology for rapid dilution immediately after discharge, etc. About the indoor experiment on the CO2 influence on marine organisms, experiment on the CO2 influence was carried out using shells, sea urchin, red sea bream, etc. In the developmental study of models for predicting environmental effects in the area around the CO2 discharge point, the 3D two-phase flow LES model was developed as a model for predicting the CO2 behavior, and the simulation of the liquid CO2 discharge was made at the planned experimental site. The model for evaluation of the biological influence was also made which can consider the interaction between two kinds of organisms. (NEDO)

  1. CO2 pellet blasting studies

    International Nuclear Information System (INIS)

    Archibald, K.E.

    1997-01-01

    Initial tests with CO 2 pellet blasting as a decontamination technique were completed in 1993 at the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory (INEL). During 1996, a number of additional CO 2 pellet blasting studies with Alpheus Cleaning Technologies, Oak Ridge National Laboratory, and Pennsylvania State University were conducted. After the testing with Alpheus was complete, an SDI-5 shaved CO 2 blasting unit was purchased by the ICPP to test and determine its capabilities before using in ICPP decontamination efforts. Results of the 1996 testing will be presented in this report

  2. FY 1999 report on the results of the R and D project on the industrial technology for the global environment. R and D of the prediction technology of environmental effects brought by CO2 ocean sequestration (Development of prediction technology of environmental effects around the point of CO2 discharge and the research support survey); 1999 nendo chikyu kankyo sangyo gijutsu kenkyu kaihatsu jigyo NEDO seika hokokusho. Nisankatanso no kaiyo kakuri ni tomonau kankyo eikyo yosoku gijutsu kenkyu kaihatsu (CO2 horyuten shuhen'iki no kankyo eikyo yosoku gijutsu no kaihatsu narabini kenkyu shien chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    For the purpose of studying viability of CO2 ocean sequestration by discharging it at the intermediate depth of ocean, the R and D were conducted of 'prediction technology of environmental effects around the point of CO2 discharge,' and the FY 1999 results were summarized. In the study of elucidation of behavior of liquid CO2 at the time of discharge, melting speed of CO2 in water and seawater, 2D CO2 concentration distribution, etc. were measured using the circulation type deep-sea simulation experimental equipment. In the study of technology to send CO2 into the sea and dilute it, the process test using mock liquid was conducted. In the indoor experiment on CO2 effects on marine organisms, conducted were the detailed experiment on long-term effects of low concentration CO2 on sea urchins and shellfish, experiment on CO2 acute effects on eggs/fry and experiment on CO2 effects on adult fish. In the developmental study of the model to predict environmental effects around the point of CO2 discharge, carried out were the improvement of the model for prediction of effects on marine organisms, study of the CO2 diffusion in topographic features supposed to be Hawaii, etc. In the international joint study, measurement/observation technology, facilities, etc. were studied in preparation for the experiment actually conducted in the sea. (NEDO)

  3. CO2 capture-sequestration

    International Nuclear Information System (INIS)

    Huffer, Elisabeth

    2008-01-01

    CO 2 capture-sequestration could be an acceptable temporary solution for the abatement of greenhouse gas releases to the atmosphere, before the implementation of new carbon-free power generation means. This paper briefly summarizes the principles of this technology: capture (post-combustion, oxi-combustion, pre-combustion); CO 2 transport and sequestration (deep saline aquifers, injection in depleted hydrocarbon reservoirs, injection in abandoned coal seams); examples of operations in progress

  4. Foraminiferal calcification and CO2

    Science.gov (United States)

    Nooijer, L. D.; Toyofuku, T.; Reichart, G. J.

    2017-12-01

    Ongoing burning of fossil fuels increases atmospheric CO2, elevates marine dissolved CO2 and decreases pH and the saturation state with respect to calcium carbonate. Intuitively this should decrease the ability of CaCO3-producing organisms to build their skeletons and shells. Whereas on geological time scales weathering and carbonate deposition removes carbon from the geo-biosphere, on time scales up to thousands of years, carbonate precipitation increases pCO2 because of the associated shift in seawater carbon speciation. Hence reduced calcification provides a potentially important negative feedback on increased pCO2 levels. Here we show that foraminifera form their calcium carbonate by active proton pumping. This elevates the internal pH and acidifies the direct foraminiferal surrounding. This also creates a strong pCO2 gradient and facilitates the uptake of DIC in the form of carbon dioxide. This finding uncouples saturation state from calcification and predicts that the added carbon due to ocean acidification will promote calcification by these organisms. This unknown effect could add substantially to atmospheric pCO2 levels, and might need to be accounted for in future mitigation strategies.

  5. Elementary reaction modeling of reversible CO/CO2 electrochemical conversion on patterned nickel electrodes

    Science.gov (United States)

    Luo, Yu; Shi, Yixiang; Li, Wenying; Cai, Ningsheng

    2018-03-01

    CO/CO2 are the major gas reactant/product in the fuel electrode of reversible solid oxide cells (RSOC). This study proposes a two-charge-transfer-step mechanism to describe the reaction and transfer processes of CO-CO2 electrochemical conversion on a patterned Ni electrode of RSOC. An elementary reaction model is developed to couple two charge transfer reactions, C(Ni)+O2-(YSZ) ↔ CO(Ni)+(YSZ) +2e- and CO(Ni)+O2-(YSZ) ↔ CO2(Ni)+(YSZ)+2e-, with adsorption/desorption, surface chemical reactions and surface diffusion. This model well validates in both solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) modes by the experimental data from a patterned Ni electrode with 10 μm stripe width at different pCO (0-0.25 atm), pCO2 (0-0.35 atm) and operating temperature (600-700 °C). This model indicates SOEC mode is dominated by charge transfer step C(Ni)+O2-(YSZ)↔CO(Ni)+(YSZ) +2e-, while SOFC mode by CO(Ni)+ O2-(YSZ)↔CO2(Ni)+(YSZ)+2e- on the patterned Ni electrode. The sensitivity analysis shows charge transfer step is the major rate-determining step for RSOC, besides, surface diffusion of CO and CO2 as well as CO2 adsorption also plays a significant role in the electrochemical reaction of SOEC while surface diffusion of CO and CO2 desorption could be co-limiting in SOFC.

  6. ACCURACY OF CO2 SENSORS

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Faulkner, David; Sullivan, Douglas P.

    2008-10-01

    Are the carbon dioxide (CO2) sensors in your demand controlled ventilation systems sufficiently accurate? The data from these sensors are used to automatically modulate minimum rates of outdoor air ventilation. The goal is to keep ventilation rates at or above design requirements while adjusting the ventilation rate with changes in occupancy in order to save energy. Studies of energy savings from demand controlled ventilation and of the relationship of indoor CO2 concentrations with health and work performance provide a strong rationale for use of indoor CO2 data to control minimum ventilation rates1-7. However, this strategy will only be effective if, in practice, the CO2 sensors have a reasonable accuracy. The objective of this study was; therefore, to determine if CO2 sensor performance, in practice, is generally acceptable or problematic. This article provides a summary of study methods and findings ? additional details are available in a paper in the proceedings of the ASHRAE IAQ?2007 Conference8.

  7. A Biomimetic Nickel Complex with a Reduced CO2 Ligand Generated by Formate Deprotonation and its Behaviour towards CO2.

    Science.gov (United States)

    Limberg, Christian; Zimmermann, Philipp; Hoof, Santina; Braun-Cula, Beatrice; Herwig, Christian

    2018-04-10

    Reduced CO2 species are key intermediates in a variety of natural and synthetic processes. In the majority of systems, however, they elude isolation or characterisation due to high reactivity or limited accessibility (heterogeneous systems) and thus formulations often remain uncertain or based on calculations only. We herein report on a Ni-CO22- complex that is unique in many ways. While its structural and electronic features help understanding the CO2 bound state in Ni,Fe carbon monoxide dehydrogenases, its reactivity sheds light on how CO2 can be converted into CO/CO32- by nickel complexes. In addition, the complex has been generated via a rare example of formate β deprotonation, a mechanistical step relevant to nickel catalysed conversion of HxCOyz- at electrodes and formate oxidation in formate dehydrogenases. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. CO2 storage in Sweden

    International Nuclear Information System (INIS)

    Ekstroem, Clas; Andersson, Annika; Kling, Aasa; Bernstone, Christian; Carlsson, Anders; Liljemark, Stefan; Wall, Caroline; Erstedt, Thomas; Lindroth, Maria; Tengborg, Per; Edstroem, Mikael

    2004-07-01

    This study considers options, that could be feasible for Sweden, to transport and geologically store CO 2 , providing that technology for electricity production with CO 2 capture will be available in the future and also acceptable from cost- and reliability point of view. As a starting point, it is assumed that a new 600-1000 MW power plant, fired with coal or natural gas, will be constructed with CO 2 capture and localised to the Stockholm, Malmoe or Goeteborg areas. Of vital importance for storage of carbon dioxide in a reservoir is the possibility to monitor its distribution, i.e. its migration within the reservoir. It has been shown in the SACS-project that the distribution of carbon dioxide within the reservoir can be monitored successfully, mainly by seismic methods. Suitable geologic conditions and a large storage potential seems to exist mainly in South West Scania, where additional knowledge on geology/hydrogeology has been obtained since the year 2000 in connection to geothermal energy projects, and in the Eastern part of Denmark, bordering on South West Scania. Storage of carbon dioxide from the Stockholm area should not be excluded, but more studies are needed to clarify the storage options within this area. The possibilities to use CO 2 for enhanced oil recovery, EOR, in i.a. the North Sea should be investigated, in order to receive incomes from the CO 2 and shared costs for infrastructure, and by this also make the CO 2 regarded as a trading commodity, and thereby achieving a more favourable position concerning acceptance, legal issues and regulations. The dimensions of CO 2 -pipelines should be similar to those for natural natural gas, although regarding some aspects they have different design and construction prerequisites. To obtain cost efficiency, the transport distances should be kept short, and possibilities for co-ordinated networks with short distribution pipelines connected to common main pipelines, should be searched for. Also, synergies

  9. The CO2nnect activities

    Science.gov (United States)

    Eugenia, Marcu

    2014-05-01

    Climate change is one of the biggest challenges we face today. A first step is the understanding the problem, more exactly what is the challenge and the differences people can make. Pupils need a wide competencies to meet the challenges of sustainable development - including climate change. The CO2nnect activities are designed to support learning which can provide pupils the abilities, skills, attitudes and awareness as well as knowledge and understanding of the issues. The project "Together for a clean and healthy world" is part of "The Global Educational Campaign CO2nnect- CO2 on the way to school" and it was held in our school in the period between February and October 2009. It contained a variety of curricular and extra-curricular activities, adapted to students aged from 11 to 15. These activities aimed to develop in students the necessary skills to understanding man's active role in improving the quality of the environment, putting an end to its degrading process and to reducing the effects of climate changes caused by the human intervention in nature, including transport- a source of CO2 pollution. The activity which I propose can be easily adapted to a wide range of age groups and linked to the curricula of many subjects: - Investigate CO2 emissions from travel to school -Share the findings using an international database -Compare and discuss CO2 emissions -Submit questions to a climate- and transport expert -Partner with other schools -Meet with people in your community to discuss emissions from transport Intended learning outcomes for pupils who participate in the CO2nnect campaign are: Understanding of the interconnected mobility- and climate change issue climate change, its causes and consequences greenhouse-gas emissions from transport and mobility the interlinking of social, environmental, cultural and economic aspects of the local transport system how individual choices and participation can contribute to creating a more sustainable development

  10. Fiscal 1997 survey report. Investigational study on the cascade utilization of thermal energy (cold heat and hot heat) (feasibility study by the off-line system); 1997 nendo chosa hokokusho. Netsu energy (reinetsu to onnetsu) no cascade riyo ni kansuru chosa kenkyu (off-line hoshiki ni yoru feasibility study)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The paper studied a system to effectively use unused and low-grade thermal energy (cold heat and hot heat) in the Tokyo-Yokohama seaside area. For transportation of thermal energy, the batch transportation, that is, off-line system was discussed which uses insulated tank loaded barges and railroad freight trains. Thermal energy supply sources are 1) 0.3 million kW class thermal power plant, and 2) LNG storage base of 3 million ton/year class. Thermal energy users are Tokyo (Haneda) Airport D.H.C. (District Heating/Cooling Co.), MM 21 D.H.C. and Shin-Kawasaki D.H.C. The cold heat energy supplied to these three is about 1.5 million Mcal/daytimes300 days/year, and the hot heat energy supplied is about 1.33 million Mcal/daytimes150 days/year. Cold heat is obtained from seawater after the LNG vaporization, and hot heat from heat extracted from thermal turbine. Subcooled ice was selected for cold heat medium, and PCM-120A for hot heat medium. For batch transportation, an STL heat storage system is used which transports plastic capsules sealed with heat medium. Oil saving of 62,000 tons/year and CO2 reduction of about 53,000 tons/year can be expected. 85 figs., 98 tabs.

  11. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  12. Nuclear power and CO2

    International Nuclear Information System (INIS)

    Chawla, R.

    2005-01-01

    Temperatures in the atmosphere have risen by nearly one degree in the twentieth century. To contain changes in global climate and their consequences, worldwide emissions of CO 2 need to be curbed drastically in the future. Even if CO 2 emissions are not taken into account, nuclear power has no economic disadvantages compared to fossil fuels. On the basis of an amount of money per ton of carbon emitted, nuclear power is cheaper than coal and, in most cases, also than natural gas. Actually, the worldwide CO 2 problem and energy generation are part of the ongoing 'sustainability' debate. The following arguments, among others, used in the discussion show the sustainable character of nuclear power: - Comparison of the risks associated with major accidents for various sources of energy show nuclear power to be relatively free from hazard. - The introduction of fast breeders and other technical factors will make it possible to use nuclear fission as an important source of energy for many centuries. - The radiotoxicity of waste over very long periods of time can be influenced, for instance, by transmutation. The need to further develop CO 2 -free nuclear power has been recognized by many countries, among them Switzerland. The Generation IV International Forum (GIF) works towards developing a new generation of nuclear power plants by 2030. It will be the symbiosis of the new types of reactors with today's modern plants which finally will establish CO 2 -free nuclear fission as a sustainable cornerstone of energy generation worldwide. That nuclear power has this potential for further development must be acknowledged generally. (orig.)

  13. Studies on coordination chemistry and bioactivity of complexes of a bidentate oxygen-oxygen donor ligand, 1,2-dibenzoylhydrazine, with Cr3+, Co2+, Ni2+, Cu2+ and Zn2+ Ions

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Lai Wee Wong; Crouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

    2003-08-01

    A new bidentate ligand, 1,2-dibenzoylhydrazine (DBHz), with OO donor sequences, was prepared. Several complexes of DBHz containing Cr(JJI), Fe(UI), Co(U), Ni(JJ), Cu(II) and Zn(TJ) ions have been synthesized and characterized by CHN analyses, IR, molar conductivity and UV/Visible spectroscopic studies. All of the compounds were tested for their antibacterial, antifungal and anticancer properties. DBHz was very effective against Pseudomonas aeruginosa, Bacillus subtilis mutant and Bacillus subtilis wild type bacteria. It was also effective against Saccaromyces cereiviceae, Candida albicans, Candida albicans lypolytica and Aspergillus ochraceous fungi. The free ligand, DBHz, in particular, was strongly active against colon cancer cell lines (HT-29), with a CD 50 value of 2.5 /μg/ml. (author)

  14. CO2 emission of Indonesian fires in 2015 estimated from satellite-derived atmospheric CO2 concentrations

    Science.gov (United States)

    Heymann, J.; Reuter, M.; Buchwitz, M.; Schneising, O.; Bovensmann, H.; Burrows, J. P.; Massart, S.; Kaiser, J. W.; Crisp, D.

    2017-02-01

    Indonesia experienced an exceptional number of fires in 2015 as a result of droughts related to the recent El Niño event and human activities. These fires released large amounts of carbon dioxide (CO2) into the atmosphere. Emission databases such as the Global Fire Assimilation System version 1.2 and the Global Fire Emission Database version 4s estimated the CO2 emission to be approximately 1100 MtCO2 in the time period from July to November 2015. This emission was indirectly estimated by using parameters like burned area, fire radiative power, and emission factors. In the study presented in this paper, we estimate the Indonesian fire CO2 emission by using the column-averaged dry air mole fraction of CO2, XCO2, derived from measurements of the Orbiting Carbon Observatory-2 satellite mission. The estimated CO2 emission is 748 ± 209 MtCO2, which is about 30% lower than provided by the emission databases.

  15. Spatiotemporal characteristics of seasonal to multidecadal variability of pCO2 and air-sea CO2 fluxes in the equatorial Pacific Ocean

    Science.gov (United States)

    Valsala, Vinu K.; Roxy, Mathew Koll; Ashok, Karumuri; Murtugudde, Raghu

    2014-12-01

    Seasonal, interannual, and multidecadal variability of seawater pCO2 and air-sea CO2 fluxes in the equatorial Pacific Ocean for the past 45 years (1961-2005) are examined using a suite of experiments performed with an offline biogeochemical model driven by reanalysis ocean products. The processes we focus on are: (a) the evolution of seasonal cycle of pCO2 and air-sea CO2 fluxes during the dominant interannual mode in the equatorial Pacific, i.e., the El Niño-Southern Oscillation (ENSO), (b) its spatiotemporal characteristics, (c) the combined and individual effects of wind and ocean dynamics on pCO2 and CO2 flux variability and their relation to canonical (eastern Pacific) and central Pacific (Modoki) ENSOs and (d) the multidecadal variability of carbon dynamics in the equatorial Pacific and its association with the Pacific Decadal Oscillations (PDO). The simulated mean and seasonal cycle of pCO2 and CO2 fluxes are comparable with the observational estimates and with other model results. A new analysis methodology based on the traditional Empirical Orthogonal Functions (EOF) applied over a time-time domain is employed to elucidate the dominant mode of interannual variability of pCO2 and air-sea CO2 fluxes at each longitude in the equatorial Pacific. The results show that the dominant interannual variability of CO2 fluxes in the equatorial Pacific (averaged over 5°N-10°S) coevolves with that of ENSO. Generally a reduced CO2 source in the central-to-eastern equatorial Pacific evident during June-July of the El Niño year (Year:0) peaks through September of Year:0 to February of Year:+1 and recovers to a normal source thereafter. In the region between 160°W and 110°W, the canonical El Niño controls the dominant variability of CO2 fluxes (mean and RMS of anomaly from 1961 to 2005 is 0.43±0.12 PgC yr-1). However, in the western (160°E-160°W) and far eastern (110°W-90°W) equatorial Pacific, CO2 flux variability is dominantly influenced by the El Ni

  16. Fang CO2 med Aminosyrer

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    2010-01-01

    Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer.......Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer....

  17. Global energy / CO2 projections

    International Nuclear Information System (INIS)

    Sinyak, Y.

    1990-09-01

    Section headings are: (1) Social and economic problems of the 21 st century and the role of energy supply systems (2) Energy-environment interactions as a central point of energy research activities (3) New ways of technological progress and its impacts on energy demand and supply (4) Long-term global energy projections (5) Comparative analysis of global long-term energy / CO 2 studies (6) Conclusions. The author shows that, in order to alleviate the negative impacts of energy systems on the climate, it will be necessary to undertake tremendous efforts to improve the energy use efficiency, to drastically change the primary energy mix, and, at the same time, to take action to reduce greenhouse emissions from other sources and increase the CO 2 sink through enhanced reforestation. (Quittner)

  18. CO2 reduction by dematerialization

    Energy Technology Data Exchange (ETDEWEB)

    Hekkert, M.P. [Department of Innovation Studies, Copernicus Institute, Utrecht University, Utrecht (Netherlands)

    2002-04-01

    Current policy for the reduction of greenhouse gases is mainly concerned with a number of types of solutions: energy saving, shifting to the use of low-carbon fuels and the implementation of sustainable energy technologies. Recent research has shown that a strategy directed at a more efficient use of materials could make a considerable contribution to reducing CO2 emissions. Moreover, the costs to society as a whole of such a measure appear to be very low.

  19. CO2 blasting in Europe

    International Nuclear Information System (INIS)

    Vankerckhoven, Patrick

    1995-01-01

    Carbon dioxide blasting can be used during the lifetime of nuclear facilities to remove deposited contamination and reduce the dose to personnel during repair and maintenance. By contrast with conventional mechanical or chemical decontamination methods, it does not leave additional secondary wastes. During the process, liquid CO 2 is expanded and converted into dry snow which is compressed and extruded to form small dry ice pellets. These low temperature pellets are blasted at high speed in a stream of compressed air against the surface to be treated where the mechanical and thermal shock embrittles the contaminating layer and severs its bond with the surface. The dry ice sublimes into the atmosphere as CO 2 gas and the loosened contamination can be removed via a ventilation and filtration system. Some examples of the effective use of CO 2 blasting are given. They include decontamination of: a supercompactor used on radioactive waste drums; the walls and floors of a nuclear fuel fabrication plant; the vacuum vessel of the Joint European Torus, hot cells; a phosphate fertilizer plant contaminated by radium 226. (UK)

  20. Improving CO2 permeation and separation performance of CO2-philic polymer membrane by blending CO2 absorbents

    Science.gov (United States)

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

    2017-07-01

    To research effects of CO2 absorption capacity and type of CO2 absorbent on the CO2 separation and free-volume properties of facilitated transport membranes, two types of CO2 absorbents, namely monoethanolamine (MEA) and ionic liquids (ILs:[P66614][Triz] and [P66614][2-Op]), were adopted. The CO2 absorption capacities of MEA, [P66614][Triz] and [P66614][2-Op] were about 0.561 mol CO2 per mol, 0.95 mol CO2 per mol and 1.60 mol CO2 per mol, respectively. All mean free-volume hole radiuses of membranes decreased after blending CO2 absorbents. After polymer membrane blended with two ILs, number of free-volume hole increased, resulting in modest increase of the fractional free volume. Both CO2 permeability and selectivity increased after blending MEA and ILs. The increasing range of CO2 permeability corresponded with CO2 absorption capacity of CO2 absorbents, and membrane blending with [P66614][2-Op] showed the highest CO2 permeability of 672.1 Barrers at 25 °C. Pebax/PEGDME membrane blending with MEA obtained the highest CO2/H2 and CO2/CH4 selectivity at 17.8 and 20.5, respectively.

  1. Mechanism for reversible CO/CO2 electrochemical conversion on a patterned nickel electrode

    Science.gov (United States)

    Luo, Yu; Li, Wenying; Shi, Yixiang; Cai, Ningsheng

    2017-10-01

    The patterned Ni negative electrode on single-crystal YSZ in CO-CO2 atmosphere is investigated in both the solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) modes. The effects of the temperature T, partial pressure of CO and CO2 (pCO and pCO2) on the electrochemical performance are measured to obtain the intrinsic kinetic parameters by natural logarithm linear fitting. The strong dependency of surface diffusion resistance on pCO implies that surface diffusion could be related to CO(Ni). The electrochemical performance had an obviously positive correlation with T and pCO. The limitation of CO2 adsorption leads to a weak dependency of polarization on pCO2. The electrochemical performance of SOEC mode in the atmosphere without CO is 1.21 times higher than that in the atmosphere without CO2, which implies that CO electrochemical reduction could be more significant than CO2 electrochemical reduction in the patterned Ni electrode. An analytical calculation is performed for the speculation of rate-limiting steps. In the SOFC mode, CO oxidation into CO2 is speculated to be rate-determining, besides, adsorbed carbon oxidation into CO could be also non-ignorable. In the SOEC mode, CO reduction into carbon could be more probably the major electrochemical reaction on the pure Ni surface.

  2. Methanation of CO2 over Zeolite-Encapsulated Nickel Nanoparticles

    DEFF Research Database (Denmark)

    Goodarzi, Farnoosh; Kang, Liqun; Wang, Feng Ryan

    2018-01-01

    Efficient methanation of CO2 relies on the development of more selective and stable heterogeneous catalysts. Here we present a simple and effective method to encapsulate Ni nanoparticles in zeolite silicalite-1. In this method, the zeolite is modified by selective desilication, which creates intr...... Ni h-1. The encapsulated Ni nanoparticles show no change in activity or selectivity after 50 h of operation, although post-catalysis characteri-sation reveals some particle migration.......Efficient methanation of CO2 relies on the development of more selective and stable heterogeneous catalysts. Here we present a simple and effective method to encapsulate Ni nanoparticles in zeolite silicalite-1. In this method, the zeolite is modified by selective desilication, which creates intra......-particle voids and mesopores that facilitate the formation of small and well-dispersed nanoparticles upon impregnation and reduction. TEM and XPS analysis confirm that a significant part of the Ni nanoparticles are situated inside the zeolite rather than on the outer surface. The encapsulation results...

  3. RODZAJE METOD SEKWESTRACJI CO2

    Directory of Open Access Journals (Sweden)

    Zofia LUBAŃSKA

    Full Text Available Z pojęciem ochrony środowiska wiąże się bardzo szeroko w ostatnim czasie omawiane zagadnienie dotyczące ograniczenia emisji CO2. Konsekwencją globalnych zmian klimatu wywołanego przez ludzi jest wzrost stężenia atmosferycznego gazów cieplarnianych, które powodują nasilający się efekt cieplarniany. Wzrasta na świecie liczba ludności, a co za tym idzie wzrasta konsumpcja na jednego mieszkańca, szczególnie w krajach szeroko rozwiniętych gospodarczo. Protokół z Kioto ściśle określa działania jakie należy podjąć w celu zmniejszenia stężenia dwutlenku węgla w atmosferze. Pomimo maksymalnej optymalizacji procesu spalania paliw kopalnianych wykorzystywanych do produkcji energii, zastosowania odnawialnych źródeł energii zmiana klimatu jest nieunikniona i konsekwentnie będzie postępować przez kolejne dekady. Prognozuje się, że duże znaczenie odegra nowoczesna technologia, która ma za zadanie wychwycenie CO2 a następnie składowanie go w odpowiednio wybranych formacjach geologicznych (CCS- Carbon Capture and Storage. Eksperci są zgodni, że ta technologia w niedalekiej przyszłości stanie się rozwiązaniem pozwalającym ograniczyć ogromną ilość emisji CO2 pochodzącą z procesów wytwarzania energii z paliw kopalnych. Z analiz Raportu IPCC wynika, iż technologia CSS może się przyczynić do ok. 20% redukcji emisji dwutlenku węgla przewidzianej do 2050 roku [3]. Zastosowanie jej napotyka na wiele barier, nie tylko technologicznych i ekonomicznych, ale także społecznych. Inną metodą dającą ujemne źródło emisji CO2 jest możliwość wykorzystania obszarów leśnych o odpowiedniej strukturze drzewostanu. Środkiem do tego celu, oprócz ograniczenia zużycia emisjogennych paliw kopalnych (przy zachowaniu zasad zrównoważonego rozwoju może być intensyfikacja zalesień. Zwiększanie lesistości i prawidłowa gospodarka leśna należy do najbardziej efektywnych sposobów kompensowania

  4. A fine-tuned fluorinated MOF addresses the needs for trace CO2 removal and air capture using physisorption.

    KAUST Repository

    Bhatt, Prashant

    2016-07-08

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, from con-fined spaces (<0.5 %) and particularly from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal-organic framework (MOF), NbOFFIVE-1-Ni, with the proper pore system (size, shape and functionality), ideal for efficient and effective traces carbon dioxide removal. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm3.cm-3) for physical adsorbents at 400 ppm CO2 and 298 K. Practically, the NbOFFIVE-1-Ni affords the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in reference physical adsorbents but considerably lower than the conventional chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2-selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on the NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2-selectivity under practical carbon capture conditions. Pertinently, the no-table hydrolytic stability positions the NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces.

  5. Plasma catalytic process for CO2 methanation

    International Nuclear Information System (INIS)

    Nizio, Magdalena

    2016-01-01

    The limited resources of oil and natural gas, together with an increasing energy demand, forces us to seek more and more efficient and cleaner energy production alternatives. Hydrogen has been recently considered as a promising energy carrier. However, there are several inherent problems to the utilization of H 2 , from its transportation to its distribution. Transformation of the H 2 molecule by fixing into a carbon-containing compound, i.e. CH 4 , will offer the possibility of using the conventional transportation network. Indeed, the Sabatier reaction, which is highly exothermic, involves the reaction of carbon dioxide and hydrogen gas in order to produce methane and water. This process, called methanation, represents a feasible approach contributing to the reduction of the CO 2 emissions in our atmosphere, through a closed carbon cycle involving the valorization of CO 2 , i.e. from capture. However, below a temperature of 250 C, the conversion becomes practically close to 0 %, whereas at higher temperatures, i.e., (≥300 C), the co-existence of secondary reactions favours the formation of CO and H 2 . This is the reason why new catalysts and process conditions are continuously being investigated in order to maximize the methane selectivity at low reaction temperatures at atmospheric pressure. Therefore, by using catalysts combined to Dielectric Barrier Discharge plasmas (DBD), the activation of the methanation reaction can be enhanced and overcome the drawbacks of existing conventional processes. Several Ni-containing catalysts were prepared using various ceria-zirconia oxides as supports, with different Ce/Zr ratios. The results obtained in the adiabatic conditions at low temperatures (ranging between 100-150 C), in the presence of catalysts activated by plasma, are promising. Indeed, the conversion of CO 2 to CH 4 is about 85 % with a selectivity close to 100 %. The same conversion in the absence of the plasma activation of the catalyst is observed at 350 C

  6. Alberta industrial synergy CO2 programs initiative

    International Nuclear Information System (INIS)

    Yildirim, E.

    1998-01-01

    The various industrial sectors within Alberta produce about 350,000 tonnes of CO 2 per day. This presentation was concerned with how this large volume and high concentration of CO 2 can be used in industrial and agricultural applications, because every tonne of CO 2 used for such purposes is a tonne that does not end up in the atmosphere. There is a good potential for an industrial synergy between the producers and users of CO 2 . The Alberta Industrial Synergy CO 2 Programs Initiative was established to ultimately achieve a balance between the producers of CO 2 and the users of CO 2 by creating ways to use the massive quantities of CO 2 produced by Alberta's hydrocarbon-based economy. The Alberta CO 2 Research Steering Committee was created to initiate and support CO 2 programs such as: (1) CO 2 use in enhanced oil recovery, (2) creation of a CO 2 production inventory, (3) survey of CO 2 users and potential users, (4) investigation of process issues such as power generation, oil sands and cement manufacturing, and (5) biofixation by plants, (6) other disposal options (e.g. in depleted oil and gas reservoirs, in aquifers, in tailings ponds, in coal beds). The single most important challenge was identified as 'rationalizing the formation of the necessary infrastructure'. Failing to do that will greatly impede efforts directed towards CO 2 utilization

  7. CO2 Capture for Cement Technology

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar

    ppmvin 1960 to 390 ppmv in 2012, probably due to human activity. A lot of research is being carried out forreducing CO2emissions from large stationary sources. Ofwhich, the carbonate looping process is anew process and has the potential to reduce CO2emissions with lower energy penalties. Most of thework...... and the main parameter that controls the performance of the carbonator, a process model integrating the carbonate looping process with the cement pyro-process was simulated. The process simulation results indicate that the CO2 emission was only 0.07 kg/ kg cl, with an energy penalty of 2 MJ/kg CO2 captured......Production of cement is an energy intensive process and is the source of considerable CO2emissions. Itis estimated that the cement industry contributes around 8% of total global CO2emissions. CO2is oneof the major greenhouse gases. In the atmosphere, the CO2concentration has increased from 310...

  8. CO2 Virtual Science Data Environment API

    Data.gov (United States)

    National Aeronautics and Space Administration — The CO2 Virtual Data Environment is a comprehensive effort at bringing together the models, data, and tools necessary to perform research on atmospheric CO2.This...

  9. ISLSCP II Globalview: Atmospheric CO2 Concentrations

    Data.gov (United States)

    National Aeronautics and Space Administration — The GlobalView Carbon Dioxide (CO2) data product contains synchronized and smoothed time series of atmospheric CO2 concentrations at selected sites that were created...

  10. ISLSCP II Globalview: Atmospheric CO2 Concentrations

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The GlobalView Carbon Dioxide (CO2) data product contains synchronized and smoothed time series of atmospheric CO2 concentrations at selected sites that...

  11. Atmospheric Pressure Non-Thermal Plasma Activation of CO2in a Packed-Bed Dielectric Barrier Discharge Reactor.

    Science.gov (United States)

    Mei, Danhua; Tu, Xin

    2017-11-17

    Direct conversion of CO 2 into CO and O 2 is performed in a packed-bed dielectric barrier discharge (DBD) non-thermal plasma reactor at low temperatures and atmospheric pressure. The maximum CO 2 conversion of 22.6 % is achieved when BaTiO 3 pellets are fully packed into the discharge gap. The introduction of γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 catalyst into the BaTiO 3 packed DBD reactor increases both CO 2 conversion and energy efficiency of the plasma process. Packing γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 upstream of the BaTiO 3 bed shows higher CO 2 conversion and energy efficiency compared with that of mid- or downstream packing modes because the reverse reaction of CO 2 conversion-the recombination of CO and O to form CO 2 -is more likely to occur in mid- and downstream modes. Compared with the γ-Al 2 O 3 support, the coupling of the DBD with the Ni catalyst shows a higher CO 2 conversion, which can be attributed to the presence of Ni active species on the catalyst surface. The argon plasma treatment of the reacted Ni catalyst provides extra evidence to confirm the role of Ni active species in the conversion of CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Bioelectrochemical conversion of CO2 to chemicals

    NARCIS (Netherlands)

    Bajracharya, Suman; Vanbroekhoven, Karolien; Buisman, Cees J.N.; Strik, David P.B.T.B.; Pant, Deepak

    2017-01-01

    The recent concept of microbial electrosynthesis (MES) has evolved as an electricity-driven production technology for chemicals from low-value carbon dioxide (CO2) using micro-organisms as biocatalysts. MES from CO2 comprises bioelectrochemical reduction of CO2 to multi-carbon organic compounds

  13. Re-evaluating the 1940s CO2 plateau

    Science.gov (United States)

    Bastos, Ana; Ciais, Philippe; Barichivich, Jonathan; Bopp, Laurent; Brovkin, Victor; Gasser, Thomas; Peng, Shushi; Pongratz, Julia; Viovy, Nicolas; Trudinger, Cathy M.

    2016-09-01

    The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940-1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940-1950 ranges between 0.9 and 2.0 Pg C yr-1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr-1 uptake, but it is unlikely to be higher. The impact of the 1940-1942 El Niño on the

  14. CO2 Permeability of Biological Membranes and Role of CO2 Channels

    Science.gov (United States)

    Endeward, Volker; Arias-Hidalgo, Mariela; Al-Samir, Samer; Gros, Gerolf

    2017-01-01

    We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO2 permeabilities in various tissues; (b) the physiological significance of the value of the CO2 permeability; (c) the mechanisms by which membrane CO2 permeability is modulated; (d) the role of the intracellular diffusivity of CO2 for the quantitative significance of cell membrane CO2 permeability; (e) the available evidence for the existence of CO2 channels in mammalian and artificial systems, with a brief view on CO2 channels in fishes and plants; and, (f) the possible significance of CO2 channels in mammalian systems. PMID:29064458

  15. Forest succession at elevated CO2

    Energy Technology Data Exchange (ETDEWEB)

    Clark, James S.; Schlesinger, William H.

    2002-02-01

    We tested hypotheses concerning the response of forest succession to elevated CO2 in the FACTS-1 site at the Duke Forest. We quantified growth and survival of naturally recruited seedlings, tree saplings, vines, and shrubs under ambient and elevated CO2. We planted seeds and seedlings to augment sample sites. We augmented CO2 treatments with estimates of shade tolerance and nutrient limitation while controlling for soil and light effects to place CO2 treatments within the context of natural variability at the site. Results are now being analyzed and used to parameterize forest models of CO2 response.

  16. Signals of ENSO related precipitation changes and atmospheric CO2 levels in Florida wetland vegetation

    Science.gov (United States)

    Wagner, F.

    2003-04-01

    Trees are equipped with a plastic phenotype, capable of sustained adjustment of leaf stomata to changes in atmospheric [CO2] concentration. With high temporal resolution and accuracy, stomatal frequency data demonstrate that Holocene climate evolution has been influenced by century-scale [CO2] fluctuations. Apart from adapting to changes in [CO2], leaf-epidermal properties are known to be sensitive to environmental factors such as water availability. In long-lived hygrophilous plants, epidermal tissue expansion is likely to be significantly influenced by changes in water availability. Synchronous analysis of the leaf-morphology in [CO2] sensitive trees and water-stress sensitive fern species from leaf assemblages preserved in peat deposits in Florida (USA), reveals distinct temporal changes in epidermal properties over the past 100 years. Stomatal frequency changes in the deciduous trees reflects the human induced [CO2] increase. Epidermal-cell density changes in fern leaves, could well be interpreted in terms of El Niño / La Niña related precipitation trends. By quantifying the leaf morphological adaptation to known environmental conditions during historical times, a new palaeobotanical proxy for past precipitation changes is introduced. Hence, in El Niño sensitive regions, analysis of buried leaf assemblages offers the unique possibility of a direct recognition of time-equivalent leaf-based signals of palaeo-atmospheric [CO2] and El Niño variability.

  17. Extraction of stevia glycosides with CO2 + water, CO2 + ethanol, and CO2 + water + ethanol

    Directory of Open Access Journals (Sweden)

    A. Pasquel

    2000-09-01

    Full Text Available Stevia leaves are an important source of natural sugar substitute. There are some restrictions on the use of stevia extract because of its distinctive aftertaste. Some authors attribute this to soluble material other than the stevia glycosides, even though it is well known that stevia glycosides have to some extent a bitter taste. Therefore, the purpose of this work was to develop a process to obtain stevia extract of a better quality. The proposed process includes two steps: i Pretreatment of the leaves by SCFE; ii Extraction of the stevia glycosides by SCFE using CO2 as solvent and water and/or ethanol as cosolvent. The mean total yield for SCFE pretreatment was 3.0%. The yields for SCFE with cosolvent of stevia glycosides were below 0.50%, except at 120 bar, 16°C, and 9.5% (molar of water. Under this condition, total yield was 3.4%. The quality of the glycosidic fraction with respect to its capacity as sweetener was better for the SCFE extract as compared to extract obtained by the conventional process. The overall extraction curves were well described by the Lack extended model.

  18. Surface decontamination using microemulsion of F-AOT in liquid/supercritical CO2

    International Nuclear Information System (INIS)

    Youn, C. H.; Gho, M. S.; Park, G. H.; Kim, H. D.; Kim, H. W.

    2003-01-01

    Conventional chemical decontamination method for surface decontamination cause not only the 2nd radioactive wastes, but also corrosion and defect on the surface of equipment. If CO 2 is used as a solvent for decontamination of radioactive contaminants, the waste can be effectively reduced by recycling of CO 2 where only contaminants are left as wastes during evaporation of CO 2 . Polar material can be dissolved by microemulsion using F-AOT and HNO 3 (1M). We use these two technique for surface decontamination. Cu and Ni specimens made by electroplating Conventional chemical decontamination method for surface decontamination cause not only the 2nd radioactive wastes, but also corrosion and defect on the surface of equipment. If CO 2 is used as a solvent for decontamination of radioactive contaminants, the waste can be effectively reduced by recycling of CO 2 where only contaminants are left as wastes during evaporation of CO 2 . Polar material can be dissolved by microemulsion using F-AOT and HNO 3 (1M). We use these two technique for surface decontamination. Cu and Ni specimens made by electroplating on the QCM surface. The QCM was used for the quantitative analysis. In the case of Cu, The 0.054μg/sec and 0.024μg/sec of decontamination efficiency were obtained in LCO 2 /ScCO 2 microemulsion respectively. The 0.066μg/sec of decontamination efficiency was obtained in the case of Ni

  19. Catalytic combustion of the retentate gas from a CO2/H2 separation membrane reactor for further CO2 enrichment and energy recovery

    International Nuclear Information System (INIS)

    Hwang, Kyung-Ran; Park, Jin-Woo; Lee, Sung-Wook; Hong, Sungkook; Lee, Chun-Boo; Oh, Duck-Kyu; Jin, Min-Ho; Lee, Dong-Wook; Park, Jong-Soo

    2015-01-01

    The CCR (catalytic combustion reaction) of the retentate gas, consisting of 90% CO 2 and 10% H 2 obtained from a CO 2 /H 2 separation membrane reactor, was investigated using a porous Ni metal catalyst in order to recover energy and further enrich CO 2 . A disc-shaped porous Ni metal catalyst, namely Al[0.1]/Ni, was prepared by a simple method and a compact MCR (micro-channel reactor) equipped with a catalyst plate was designed for the CCR. CO 2 and H 2 concentrations of 98.68% and 0.46%, respectively, were achieved at an operating temperature of 400 °C, GHSV (gas-hourly space velocity) of 50,000 h −1 and a H 2 /O 2 ratio (R/O) of 2 in the unit module. In the case of the MCR, a sheet of the Ni metal catalyst was easily installed along with the other metal plates and the concentration of CO 2 in the retentate gas increased up to 96.7%. The differences in temperatures measured before and after the CCR were 31 °C at the product outlet and 19 °C at the N 2 outlet in the MCR. The disc-shaped porous metal catalyst and MCR configuration used in this study exhibit potential advantages, such as high thermal transfer resulting in improved energy recovery rate, simple catalyst preparation, and easy installation of the catalyst in the MCR. - Highlights: • The catalytic combustion of a retentate gas obtained from the H 2 /CO 2 separation membrane. • A disc-shaped porous nickel metal catalyst and a micro-channel reactor for catalytic hydrogen combustion. • CO 2 enrichment up to 98.68% at 400 °C, 50,000 h −1 and H 2 /O 2 ratio of 2.

  20. Changes in photosynthesis, mesophyll conductance to CO2, and isoprenoid emissions in Populus nigra plants exposed to excess nickel

    International Nuclear Information System (INIS)

    Velikova, Violeta; Tsonev, Tsonko; Loreto, Francesco; Centritto, Mauro

    2011-01-01

    Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 μM Ni (Ni 30 and Ni 200 ). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO 2 ] than in control leaves. However chloroplastic [CO 2 ] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-β-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. - Graphical abstract: Visible damage caused by Ni treatment. 1 - Ni 0 (control plants); 2 - Ni 200 ; M = mature and D = developing Populus nigra leaves. Display Omitted Highlights: → We study the effect of Ni pollution on photosynthesis and isoprenoid emissions. → Ni stress significantly decreases photosynthesis. The main limitations are attributed to mesophyll conductance and metabolism impairment. → Constitutive isoprene emission was significantly stimulated in Ni-stressed leaves. Exposure to enhanced Ni concentration induces cis-beta-ocimene and linalool emissions. - The study reveals consequences of Ni stress on plant physiology, namely increasing diffusional limitation to photosynthesis and isoprenoid emissions.

  1. CO2 flux from Javanese mud volcanism

    Science.gov (United States)

    Burton, M. R.; Arzilli, F.; Chiarugi, A.; Marliyani, G. I.; Anggara, F.; Harijoko, A.

    2017-01-01

    Abstract Studying the quantity and origin of CO2 emitted by back‐arc mud volcanoes is critical to correctly model fluid‐dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s−1 (117 t d−1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d−1, comparable with the expected back‐arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man‐portable active remote sensing instruments for probing natural gas releases, enabling bottom‐up quantification of CO2 fluxes. PMID:28944134

  2. Modeling of CO2 storage in aquifers

    International Nuclear Information System (INIS)

    Savioli, Gabriela B; Santos, Juan E

    2011-01-01

    Storage of CO 2 in geological formations is a means of mitigating the greenhouse effect. Saline aquifers are a good alternative as storage sites due to their large volume and their common occurrence in nature. The first commercial CO 2 injection project is that of the Sleipner field in the Utsira Sand aquifer (North Sea). Nevertheless, very little was known about the effectiveness of CO 2 sequestration over very long periods of time. In this way, numerical modeling of CO 2 injection and seismic monitoring is an important tool to understand the behavior of CO 2 after injection and to make long term predictions in order to prevent CO 2 leaks from the storage into the atmosphere. The description of CO 2 injection into subsurface formations requires an accurate fluid-flow model. To simulate the simultaneous flow of brine and CO 2 we apply the Black-Oil formulation for two phase flow in porous media, which uses the PVT data as a simplified thermodynamic model. Seismic monitoring is modeled using Biot's equations of motion describing wave propagation in fluid-saturated poroviscoelastic solids. Numerical examples of CO 2 injection and time-lapse seismics using data of the Utsira formation show the capability of this methodology to monitor the migration and dispersal of CO 2 after injection.

  3. CO2 flux from Javanese mud volcanism

    Science.gov (United States)

    Queißer, M.; Burton, M. R.; Arzilli, F.; Chiarugi, A.; Marliyani, G. I.; Anggara, F.; Harijoko, A.

    2017-06-01

    Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s-1 (117 t d-1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d-1, comparable with the expected back-arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO2 fluxes.

  4. Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Teng, Baiyang

    2013-05-01

    Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.

  5. Explaining CO2 fluctuations observed in snowpacks

    Science.gov (United States)

    Graham, Laura; Risk, David

    2018-02-01

    Winter soil carbon dioxide (CO2) respiration is a significant and understudied component of the global carbon (C) cycle. Winter soil CO2 fluxes can be surprisingly variable, owing to physical factors such as snowpack properties and wind. This study aimed to quantify the effects of advective transport of CO2 in soil-snow systems on the subdiurnal to diurnal (hours to days) timescale, use an enhanced diffusion model to replicate the effects of CO2 concentration depletions from persistent winds, and use a model-measure pairing to effectively explore what is happening in the field. We took continuous measurements of CO2 concentration gradients and meteorological data at a site in the Cape Breton Highlands of Nova Scotia, Canada, to determine the relationship between wind speeds and CO2 levels in snowpacks. We adapted a soil CO2 diffusion model for the soil-snow system and simulated stepwise changes in transport rate over a broad range of plausible synthetic cases. The goal was to mimic the changes we observed in CO2 snowpack concentration to help elucidate the mechanisms (diffusion, advection) responsible for observed variations. On subdiurnal to diurnal timescales with varying winds and constant snow levels, a strong negative relationship between wind speed and CO2 concentration within the snowpack was often identified. Modelling clearly demonstrated that diffusion alone was unable to replicate the high-frequency CO2 fluctuations, but simulations using above-atmospheric snowpack diffusivities (simulating advective transport within the snowpack) reproduced snow CO2 changes of the observed magnitude and speed. This confirmed that wind-induced ventilation contributed to episodic pulsed emissions from the snow surface and to suppressed snowpack concentrations. This study improves our understanding of winter CO2 dynamics to aid in continued quantification of the annual global C cycle and demonstrates a preference for continuous wintertime CO2 flux measurement systems.

  6. Explaining CO2 fluctuations observed in snowpacks

    Directory of Open Access Journals (Sweden)

    L. Graham

    2018-02-01

    Full Text Available Winter soil carbon dioxide (CO2 respiration is a significant and understudied component of the global carbon (C cycle. Winter soil CO2 fluxes can be surprisingly variable, owing to physical factors such as snowpack properties and wind. This study aimed to quantify the effects of advective transport of CO2 in soil–snow systems on the subdiurnal to diurnal (hours to days timescale, use an enhanced diffusion model to replicate the effects of CO2 concentration depletions from persistent winds, and use a model–measure pairing to effectively explore what is happening in the field. We took continuous measurements of CO2 concentration gradients and meteorological data at a site in the Cape Breton Highlands of Nova Scotia, Canada, to determine the relationship between wind speeds and CO2 levels in snowpacks. We adapted a soil CO2 diffusion model for the soil–snow system and simulated stepwise changes in transport rate over a broad range of plausible synthetic cases. The goal was to mimic the changes we observed in CO2 snowpack concentration to help elucidate the mechanisms (diffusion, advection responsible for observed variations. On subdiurnal to diurnal timescales with varying winds and constant snow levels, a strong negative relationship between wind speed and CO2 concentration within the snowpack was often identified. Modelling clearly demonstrated that diffusion alone was unable to replicate the high-frequency CO2 fluctuations, but simulations using above-atmospheric snowpack diffusivities (simulating advective transport within the snowpack reproduced snow CO2 changes of the observed magnitude and speed. This confirmed that wind-induced ventilation contributed to episodic pulsed emissions from the snow surface and to suppressed snowpack concentrations. This study improves our understanding of winter CO2 dynamics to aid in continued quantification of the annual global C cycle and demonstrates a preference for continuous wintertime CO2 flux

  7. Technological CO2 reduction potential for transport in CO2; Technologisch CO2-reductie potentieel voor transport in 2040

    Energy Technology Data Exchange (ETDEWEB)

    Passier, G.L.M.; Driever, J.P.M.; Van Baalen, J.; Foster, D.; Kadijk, G.; Verbeek, R.

    2008-09-15

    TNO conducted a study of the CO2 reduction potential in Dutch continental transport up to 2040. The main conclusion is that reduction of approximately 40% in CO2 emissions compared to 1990 is feasible by means of technological innovations and deployment of alternative energy sources. (mk) [Dutch] TNO heeft een studie uitgevoerd naar CO2-besparingsmogelijkheden in het Nederlandse continentaal vervoer tot het jaar 2040. De hoofdconclusie is dat een reductie van ca. 40% in de CO2-uitstoot ten opzichte van 1990 mogelijk is door middel van technologische innovaties en toepassing van alternatieve energiebronnen.

  8. Different CO2 absorbents-modified SBA-15 sorbent for highly selective CO2 capture

    Science.gov (United States)

    Liu, Xiuwu; Zhai, Xinru; Liu, Dongyang; Sun, Yan

    2017-05-01

    Different CO2 absorbents-modified SBA-15 materials are used as CO2 sorbent to improve the selectivity of CH4/CO2 separation. The SBA-15 sorbents modified by physical CO2 absorbents are very limited to increasing CO2 adsorption and present poor selectivity. However, the SBA-15 sorbents modified by chemical CO2 absorbents increase CO2 adsorption capacity obviously. The separation coefficients of CO2/CH4 increase in this case. The adsorption and regeneration properties of the SBA-15 sorbents modified by TEA, MDEA and DIPA have been compared. The SBA-15 modified by triethanolamine (TEA) presents better CO2/CH4 separation performance than the materials modified by other CO2 absorbents.

  9. Energyless CO2 Absorption, Generation, and Fixation Using Atmospheric CO2.

    Science.gov (United States)

    Inagaki, Fuyuhiko; Okada, Yasuhiko; Matsumoto, Chiaki; Yamada, Masayuki; Nakazawa, Kenta; Mukai, Chisato

    2016-01-01

    From an economic and ecological perspective, the efficient utilization of atmospheric CO2 as a carbon resource should be a much more important goal than reducing CO2 emissions. However, no strategy to harvest CO2 using atmospheric CO2 at room temperature currently exists, which is presumably due to the extremely low concentration of CO2 in ambient air (approximately 400 ppm=0.04 vol%). We discovered that monoethanolamine (MEA) and its derivatives efficiently absorbed atmospheric CO2 without requiring an energy source. We also found that the absorbed CO2 could be easily liberated with acid. Furthermore, a novel CO2 generator enabled us to synthesize a high value-added material (i.e., 2-oxazolidinone derivatives based on the metal catalyzed CO2-fixation at room temperature) from atmospheric CO2.

  10. Global CO2 Emission from Volcanic Lakes

    Science.gov (United States)

    Perez, N.; Hernandez Perez, P. A.; Padilla, G.; Melian Rodriguez, G.; Padron, E.; Barrancos, J.; Calvo, D.; Kusukabe, M.; Mori, T.; Nolasco, D.

    2009-12-01

    During the last two decades, scientists have paid attention to CO2 volcanic emissions and its contribution to the global C budget. Excluding MORBs as a net source of CO2 to the atmosphere, the global CO2 discharge from subaerial volcanism has been estimated about 300 Mt y-1 and this rate accounts for both visible (plume & fumaroles) and non-visible (diffuse) volcanic gas emanations (Mörner & Etíope, 2002). However, CO2 emissions from volcanic lakes have not been considered to estimate the global CO2 discharge from subaerial volcanoes. In order to improve this global CO2 emission rate and estimate the global CO2 emission from volcanic lakes, an extensive research on CO2 emission of volcanic lakes from Phillipines, Nicaragua, Guatemala, Mexico, Indonesia, Germany, France, Cameroon, Costa Rica, El Salvador and Ecuador had been recently carried out. In-situ measurements of CO2 efflux from the surface environment of volcanic lakes were performed by means of a modified floating device of the accumulation chamber method. To quantify the total CO2 emission from each volcanic lake, CO2 efflux maps were constructed using sequential Gaussian simulations (sGs). CO2 emission rates were normalized by the lake area (km2), and volcanic lakes were grouped following classification in acid, alkaline and neutral lakes. The observed average normalized CO2 emission rate values increase from alkaline (5.5 t km-2 d-1), neutral (210.0 t km-2 d-1), to acid (676.8 t km-2 d-1) volcanic lakes. Taking into account (i) these normalized CO2 emission rates from 31 volcanic lakes, (ii) the number of volcanic lakes in the world (~ 1100), (iii) the fraction of the investigated alkaline (45%), neutral (39%), and acid (16%) volcanic lakes, and (iv) the average areas of the investigated alkaline (36,8 km2), neutral (3,7 km2), and acid (0,5 km2) volcanic lakes; the global CO2 emission from volcanic lakes is about ~ 182 Mt year-1. This estimated value is about ~ 50% of the actual estimated global CO2

  11. Metal-Organic Framework-Stabilized CO2/Water Interfacial Route for Photocatalytic CO2Conversion.

    Science.gov (United States)

    Luo, Tian; Zhang, Jianling; Li, Wei; He, Zhenhong; Sun, Xiaofu; Shi, Jinbiao; Shao, Dan; Zhang, Bingxing; Tan, Xiuniang; Han, Buxing

    2017-11-29

    Here, we propose a CO 2 /water interfacial route for photocatalytic CO 2 conversion by utilizing a metal-organic framework (MOF) as both an emulsifier and a catalyst. The CO 2 reduction occurring at the CO 2 /water interface produces formate with remarkably enhanced efficiency as compared with that in conventional solvent. The route is efficient, facile, adjustable, and environmentally benign, which is applicable for the CO 2 transformation photocatalyzed by different kinds of MOFs.

  12. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone....... The CO2 capture capacity of limestone in the raw meal is lower than for pure limestone. The difference in the CO2 capture capacity decreases with an increase in cycle number. The calcination conditions and composition are major factors that influence the CO2 capture capacity of limestone. At 850 °C in N2...

  13. Advanced technology development reducing CO2 emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sup

    2010-09-15

    Responding to Korean government policies on green growth and global energy/ environmental challenges, SK energy has been developing new technologies to reduce CO2 emissions by 1) CO2 capture and utilization, 2) efficiency improvement, and 3) Li-ion batteries. The paper introduces three advanced technologies developed by SK energy; GreenPol, ACO, and Li-ion battery. Contributing to company vision, a more energy and less CO2, the three technologies are characterized as follows. GreenPol utilizes CO2 as a feedstock for making polymer. Advanced Catalytic Olefin (ACO) reduces CO2 emission by 20% and increase olefin production by 17%. Li-ion Batteries for automotive industries improves CO2 emission.

  14. CO2 sequestration: Storage capacity guideline needed

    Science.gov (United States)

    Frailey, S.M.; Finley, R.J.; Hickman, T.S.

    2006-01-01

    Petroleum reserves are classified for the assessment of available supplies by governmental agencies, management of business processes for achieving exploration and production efficiency, and documentation of the value of reserves and resources in financial statements. Up to the present however, the storage capacity determinations made by some organizations in the initial CO2 resource assessment are incorrect technically. New publications should thus cover differences in mineral adsorption of CO2 and dissolution of CO2 in various brine waters.

  15. CO2 Allowance and Electricity Price Interaction

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    With the introduction of CO2 emission constraints on power generators in the European Union, climate policy is starting to have notable effects on energy markets. This paper sheds light on the links between CO2 prices, electricity prices, and electricity costs to industry. It is based on a series of interviews with industrial and electricity stakeholders, as well as a rich literature seeking to estimate the exact effect of CO2 prices on electricity prices.

  16. CO2 capture in different carbon materials.

    Science.gov (United States)

    Jiménez, Vicente; Ramírez-Lucas, Ana; Díaz, José Antonio; Sánchez, Paula; Romero, Amaya

    2012-07-03

    In this work, the CO(2) capture capacity of different types of carbon nanofibers (platelet, fishbone, and ribbon) and amorphous carbon have been measured at 26 °C as at different pressures. The results showed that the more graphitic carbon materials adsorbed less CO(2) than more amorphous materials. Then, the aim was to improve the CO(2) adsorption capacity of the carbon materials by increasing the porosity during the chemical activation process. After chemical activation process, the amorphous carbon and platelet CNFs increased the CO(2) adsorption capacity 1.6 times, whereas fishbone and ribbon CNFs increased their CO(2) adsorption capacity 1.1 and 8.2 times, respectively. This increase of CO(2) adsorption capacity after chemical activation was due to an increase of BET surface area and pore volume in all carbon materials. Finally, the CO(2) adsorption isotherms showed that activated amorphous carbon exhibited the best CO(2) capture capacity with 72.0 wt % of CO(2) at 26 °C and 8 bar.

  17. Synthetic biology for CO2fixation.

    Science.gov (United States)

    Gong, Fuyu; Cai, Zhen; Li, Yin

    2016-11-01

    Recycling of carbon dioxide (CO 2 ) into fuels and chemicals is a potential approach to reduce CO 2 emission and fossil-fuel consumption. Autotrophic microbes can utilize energy from light, hydrogen, or sulfur to assimilate atmospheric CO 2 into organic compounds at ambient temperature and pressure. This provides a feasible way for biological production of fuels and chemicals from CO 2 under normal conditions. Recently great progress has been made in this research area, and dozens of CO 2 -derived fuels and chemicals have been reported to be synthesized by autotrophic microbes. This is accompanied by investigations into natural CO 2 -fixation pathways and the rapid development of new technologies in synthetic biology. This review first summarizes the six natural CO 2 -fixation pathways reported to date, followed by an overview of recent progress in the design and engineering of CO 2 -fixation pathways as well as energy supply patterns using the concept and tools of synthetic biology. Finally, we will discuss future prospects in biological fixation of CO 2 .

  18. Life testing of metal-ceramic CO2 lasers

    Science.gov (United States)

    Fahlen, T. S.; Radecki, D. J.; Reynolds, R. S.; Targ, R.

    1971-01-01

    The main purpose of this program was to determine the life characteristics of nine space-qualified, metal-ceramic CO2 lasers. Lifetimes ranged between about 400 hours to over 2000 hours (the limit of testing) with a high degree of consistency in like groups. In all cases the tubes which had failed could be restored to near their original power by doubling the cathode current for 30 minutes. Periodic rejuvenation allowed operation for the full 2000 hours on all tubes. The failure mechanism appears to involve formation of NiO and C on the nickel cathode emission surface with subsequent absorption of tube gases.

  19. Experimental Ion Mobility measurements in Ne-CO$_2$ and CO$_2$-N$_2$ mixtures

    CERN Document Server

    Encarnação, P.M.C.C.; Veenhof, R.; Neves, P.N.B.; Santos, F.P.; Trindade, A.M.F.; Borges, F.I.G.M.; Conde, C.A.N.

    2016-01-01

    In this paper we present the experimental results for the mobility, K0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N2) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm2V−1s−1 in the 10%-99% interval of CO2, and from 4.61 ± 0.19 to 3.00 ± 0.09 cm2V−1s−1 for the second peak observed (10%–25% of CO2). For the CO2-N2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+(CO2), with a second peak appearing for CO2 concentrations below 10%. This secon...

  20. Highly Dispersed Metal Carbide on ZIF-Derived Pyridinic-N-Doped Carbon for CO2Enrichment and Selective Hydrogenation.

    Science.gov (United States)

    Li, Yunhua; Cai, Xiaohu; Chen, Sijing; Zhang, Hua; Zhang, Kevin H L; Hong, Jinqing; Chen, Binghui; Kuo, Dong-Hau; Wang, Wenju

    2018-02-08

    Catalytic conversion of CO 2 into chemicals is a critical issue for energy and environmental research. Among such reactions, converting CO 2 into CO has been regarded as a significant foundation to generate a liquid fuels and chemicals on a large scale. In this work, zeolitic imidazolate framework-derived N-doped carbon-supported metal carbide catalysts (M/ZIF-8-C; M=Ni, Fe, Co and Cu) with highly dispersed metal carbide were prepared for selective CO 2 hydrogenation. Under the same metal loadings, catalytic activity for CO 2 hydrogenation to CO follows the order: Ni/ZIF-8-C≈Fe/ZIF-8-C>Co/ZIF-8-C>Cu/ZIF-8-C. These catalysts are composed of carbide or metal supported on pyridinic N sites within the N-doped carbon structure. ZIF-8-derived pyridinic nitrogen and carbide effect CO 2 adsorption, whereas dispersed Ni or Fe carbide and metal species serve as an active site for CO 2 hydrogenation. The supported Ni catalyst exhibits extraordinary catalytic performance, which results from high dispersion of the metal and exposure of the carbide. Based on high-sensitivity low-energy ion scattering (HS-LEIS) and line scan results, density functional theory (DFT) was used to understand reaction mechanism of selective CO 2 hydrogenation over Ni/ZIF-8-C. The product CO is derived mainly from the direct cleavage of C-O bonds in CO 2 * rather than decomposition of COOH*. The CO* desorption energy on Ni/ZIF-8-C is lower than that for further hydrogenation and dissociation. Comparison of Ni/ZIF-8-C with ZIF-8-C indicates that the combined effects of the highly dispersed metal or carbide and weak CO adsorption result in high CO selectivity for CO 2 hydrogenation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. CO2-Brine Displacement in Geological CO2 Sequestration: Microfluidic Flow Model Study

    Science.gov (United States)

    Cao, S. C.; Jung, J.

    2014-12-01

    Geological CO2 sequestration is a promising method to reduce atmospheric CO2 and deep saline aquifers is one of the most important options due to their capacity for CO2 storage. Thus, a better understanding of two immiscible brine-CO2 mobility and its saturation, including invading patterns in deep saline aquifers as CO2 storage sites is required. Lenormand (1990) explored the invading patterns of two immiscible fluids in porous media with a transition region and three dominant regions: capillary fingering, viscous fingering, and stable displacement. These are determined by two main aspect ratios Nm and Nc through experimental studies using micromodel. Micromodel provides the opportunity to discover unrecognized processes, and test existing theories and assumptions in fluid flow through porous media. In this study, the micromodel was used to explore the effects of the scCO2 injecting velocity and ionic strength on invading patterns in geological CO2 sequestration. When scCO2 was injected into the micromodel that has already saturated with brine, the brine in the micromodel was displaced by injected scCO2. Continuous scCO2 injection into the micromodel leaded the scCO2 to pass through the micromodel. And the scCO2-brine displacement distribution in the micromodel remained constant during additional 100 PV scCO2 injection after injecting scCO2 passed through micromodel. When scCO2 passed through the porous media, the scCO2-brine displacement distribution represented the maximum displacement ratio. Results showed that scCO2-brine displacement ratios increased with: elevated pressures in the range of 3MPa~8MPa, decreased ionic strength from 5M to 1M NaCl, and increased scCO2 injecting velocity up to 40 μL/min. Also, Nm and Nc obtained in this study are located in transition region of the invading patterns suggested by Lenormand (1990).

  2. 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

  3. Recent development of capture of CO2

    CERN Document Server

    Chavez, Rosa Hilda

    2014-01-01

    "Recent Technologies in the capture of CO2" provides a comprehensive summary on the latest technologies available to minimize the emission of CO2 from large point sources like fossil-fuel power plants or industrial facilities. This ebook also covers various techniques that could be developed to reduce the amount of CO2 released into the atmosphere. The contents of this book include chapters on oxy-fuel combustion in fluidized beds, gas separation membrane used in post-combustion capture, minimizing energy consumption in CO2 capture processes through process integration, characterization and application of structured packing for CO2 capture, calcium looping technology for CO2 capture and many more. Recent Technologies in capture of CO2 is a valuable resource for graduate students, process engineers and administrative staff looking for real-case analysis of pilot plants. This eBook brings together the research results and professional experiences of the most renowned work groups in the CO2 capture field...

  4. Corn residue removal and CO2 emissions

    Science.gov (United States)

    Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are the primary greenhouse gases (GHG) emitted from the soil due to agricultural activities. In the short-term, increases in CO2 emissions indicate increased soil microbial activity. Soil micro-organisms decompose crop residues and release...

  5. Capturing CO2 via reactions in nanopores.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Kevin; Nenoff, Tina Maria; Criscenti, Louise Jacqueline; Tang, Z; Dong, J. H.

    2008-10-01

    This one-year exploratory LDRD aims to provide fundamental understanding of the mechanism of CO2 scrubbing platforms that will reduce green house gas emission and mitigate the effect of climate change. The project builds on the team members expertise developed in previous LDRD projects to study the capture or preferential retention of CO2 in nanoporous membranes and on metal oxide surfaces. We apply Density Functional Theory and ab initio molecular dynamics techniques to model the binding of CO2 on MgO and CaO (100) surfaces and inside water-filled, amine group functionalized silica nanopores. The results elucidate the mechanisms of CO2 trapping and clarify some confusion in the literature. Our work identifies key future calculations that will have the greatest impact on CO2 capture technologies, and provides guidance to science-based design of platforms that can separate the green house gas CO2 from power plant exhaust or even from the atmosphere. Experimentally, we modify commercial MFI zeolite membranes and find that they preferentially transmit H2 over CO2 by a factor of 34. Since zeolite has potential catalytic capability to crack hydrocarbons into CO2 and H2, this finding paves the way for zeolite membranes that can convert biofuel into H2 and separate the products all in one step.

  6. The challenges of monitoring CO2 storage

    NARCIS (Netherlands)

    Arts, R.; Vandeweijer, V.

    2011-01-01

    At present there is an increasing consensus that the global climate is changing as a result of increased atmospheric concentration of greenhouse gases such as CO2. The emissions of CO2 are directly linked to the abundant application of fossil energy sources. © 2011 Society of Exploration

  7. Flow assurance studies for CO2 transport

    NARCIS (Netherlands)

    Veltin, J.; Belfroid, S.P.C.

    2013-01-01

    In order to compensate for the relative lack of experience of the CCTS community, Flow Assurance studies of new CO2 pipelines and networks are a very important step toward reliable operation. This report details a typical approach for Flow Assurance study of CO2 transport pipeline. Considerations to

  8. Options for CO2 sequestration in Kuwait

    NARCIS (Netherlands)

    Neele, F.; Vandeweijer, V.; Mayyan, H.; Sharma, S.R.; Kamal, D.

    2017-01-01

    In preparation for future requirements to abate CO2 emission levels, a CO2 storage feasibility study was carried out for the country of Kuwait. At present, no definite plans exist to install capture facilities at the larger emission points in the country; the study presented is one of the first

  9. Monitoring Options for CO2 Storage

    NARCIS (Netherlands)

    Arts, R.; Winthaegen, P.

    2005-01-01

    This chapter provides an overview of various monitoring techniques for CO2 storage that is structured into three categories-instrumentation in a well (monitoring well); instrumentation at the (near) surface (surface geophysical methods); and sampling at the (near) surface measuring CO2

  10. CO2 Absorbing Capacity of MEA

    Directory of Open Access Journals (Sweden)

    José I. Huertas

    2015-01-01

    Full Text Available We describe the use of a gas bubbler apparatus in which the gas phase is bubbled into a fixed amount of absorbent under standard conditions as a uniform procedure for determining the absorption capacity of solvents. The method was systematically applied to determine the CO2 absorbing capacity of MEA (Ac at several aqueous MEA (β and gas-phase CO2 concentrations. Ac approached the nominal CO2 absorbing capacity of MEA (720 g CO2/kg MEA at very low β levels, increasing from 447.9±18.1 to 581.3±32.3 g CO2/kg MEA as β was reduced from 30 to 2.5% (w/w. Ac did not depend on the CO2 concentration in the inlet gas stream as long as the gas stream did not include other amine sensitive components. During the bubbling tests the outlet CO2 concentration profiles exhibited a sigmoidal shape that could be described by an exponential equation characterized by an efficiency factor (a and a form factor (n. Statistical analysis based on correlation analysis indicated that in all cases the experimental data fit the equation well when a was 6.1±0.35 and n was 2.5±0.12. The results of these experiments may be used to optimize scrubber designs for CO2 sequestration from fossil fuel derived flue gases.

  11. Toxic emissions and devaluated CO2-neutrality

    DEFF Research Database (Denmark)

    Czeskleba-Dupont, Rolf

    with a climate policy whose goals of CO2-reduction were made operational by green-wash. Arguments are given for the devaluation of CO2- neutrality in case of burning wood. Alternative practices as storing C in high quality wood products and/or leaving wood in the forest are recommended. A counter...

  12. Increasing CO2 storage in oil recovery

    International Nuclear Information System (INIS)

    Jessen, Kristian; Kovscek, Anthony R.; Orr, Franklin M.

    2005-01-01

    Oil fields offer a significant potential for storing CO 2 and will most likely be the first large scale geological targets for sequestration as the infrastructure, experience and permitting procedures already exist. The problem of co-optimizing oil production and CO 2 storage differs significantly from current gas injection practice due to the cost-benefit imbalance resulting from buying CO 2 for enhanced oil recovery projects. Consequently, operators aim to minimize the amount of CO 2 required to sweep an oil reservoir. For sequestration purposes, where high availability of low cost CO 2 is assumed, the design parameters of enhanced oil recovery processes must be re-defined to optimize the amount of CO 2 left in the reservoir at the time of abandonment. To redefine properly the design parameters, thorough insight into the mechanisms controlling the pore scale displacement efficiency and the overall sweep efficiency is essential. We demonstrate by calculation examples the different mechanisms controlling the displacement behavior of CO 2 sequestration schemes, the interaction between flow and phase equilibrium and how proper design of the injection gas composition and well completion are required to co-optimize oil production and CO 2 storage

  13. The ins and outs of CO2.

    Science.gov (United States)

    Raven, John A; Beardall, John

    2016-01-01

    It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3(-). The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3(-) use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3(-) active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3(-) can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3(-) pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3(-). Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  14. The ins and outs of CO2

    Science.gov (United States)

    Raven, John A.; Beardall, John

    2016-01-01

    It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3 –. The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3 – use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3 – active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3 – can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3 – pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3 –. Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation. PMID:26466660

  15. Silvering substrates after CO2 snow cleaning

    Science.gov (United States)

    Zito, Richard R.

    2005-09-01

    There have been some questions in the astronomical community concerning the quality of silver coatings deposited on substrates that have been cleaned with carbon dioxide snow. These questions center around the possible existence of carbonate ions left behind on the substrate by CO2. Such carbonate ions could react with deposited silver to produce insoluble silver carbonate, thereby reducing film adhesion and reflectivity. Carbonate ions could be produced from CO2 via the following mechanism. First, during CO2 snow cleaning, a small amount of moisture can condense on a surface. This is especially true if the jet of CO2 is allowed to dwell on one spot. CO2 gas can dissolve in this moisture, producing carbonic acid, which can undergo two acid dissociations to form carbonate ions. In reality, it is highly unlikely that charged carbonate ions will remain stable on a substrate for very long. As condensed water evaporates, Le Chatelier's principle will shift the equilibrium of the chain of reactions that produced carbonate back to CO2 gas. Furthermore, the hydration of CO2 reaction of CO2 with H20) is an extremely slow process, and the total dehydrogenation of carbonic acid is not favored. Living tissues that must carry out the equilibration of carbonic acid and CO2 use the enzyme carbonic anhydrase to speed up the reaction by a factor of one million. But no such enzymatic action is present on a clean mirror substrate. In short, the worst case analysis presented below shows that the ratio of silver atoms to carbonate radicals must be at least 500 million to one. The results of chemical tests presented here support this view. Furthermore, film lift-off tests, also presented in this report, show that silver film adhesion to fused silica substrates is actually enhanced by CO2 snow cleaning.

  16. Dynamics of CO2 fluxes and concentrations during a shallow subsurface CO2 release

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, J.L.; Hilley, G.E.; Dobeck, L.; Spangler, L.

    2009-09-01

    A field facility located in Bozeman, Montana provides the opportunity to test methods to detect, locate, and quantify potential CO2 leakage from geologic storage sites. From 9 July to 7 August 2008, 0.3 t CO2 d{sup -1} were injected from a 100-m long, {approx}2.5 m deep horizontal well. Repeated measurements of soil CO2 fluxes on a grid characterized the spatio-temporal evolution of the surface leakage signal and quantified the surface leakage rate. Infrared CO2 concentration sensors installed in the soil at 30 cm depth at 0 to 10 m from the well and at 4 cm above the ground at 0 and 5 m from the well recorded surface breakthrough of CO2 leakage and migration of CO2 leakage through the soil. Temporal variations in CO2 concentrations were correlated with atmospheric and soil temperature, wind speed, atmospheric pressure, rainfall, and CO2 injection rate.

  17. Potential and economics of CO2 sequestration

    International Nuclear Information System (INIS)

    Jean-Baptiste, Ph.; Ciais, Ph.; Orr, J.

    2001-01-01

    Increasing atmospheric level of greenhouse gases are causing global warming and putting at risk the global climate system. The main anthropogenic greenhouse gas is CO 2 . Some techniques could be used to reduced CO 2 emission and stabilize atmospheric CO 2 concentration, including i) energy savings and energy efficiency, ii) switch to lower carbon content fuels (natural gas) and use energy sources with zero CO 2 emissions such as renewable or nuclear energy, iii) capture and store CO 2 from fossil fuels combustion, and enhance the natural sinks for CO 2 (forests, soils, ocean...). The purpose of this report is to provide an overview of the technology and cost for capture and storage of CO 2 and to review the various options for CO 2 sequestration by enhancing natural carbon sinks. Some of the factors which will influence application, including environmental impact, cost and efficiency, are discussed. Capturing CO 2 and storing it in underground geological reservoirs appears as the best environmentally acceptable option. It can be done with existing technology, however, substantial R and D is needed to improve available technology and to lower the cost. Applicable to large CO 2 emitting industrial facilities such as power plants, cement factories, steel industry, etc., which amount to about 30% of the global anthropic CO 2 emission, it represents a valuable tool in the baffle against global warming. About 50% of the anthropic CO 2 is being naturally absorbed by the biosphere and the ocean. The 'natural assistance' provided by these two large carbon reservoirs to the mitigation of climate change is substantial. The existing natural sinks could be enhanced by deliberate action. Given the known and likely environmental consequences, which could be very damaging indeed, enhancing ocean sinks does not appears as a satisfactory option. In contrast, the promotion of land sinks through demonstrated carbon-storing approach to agriculture, forests and land management could

  18. Carbonation and CO2 uptake of concrete

    International Nuclear Information System (INIS)

    Yang, Keun-Hyeok; Seo, Eun-A; Tae, Sung-Ho

    2014-01-01

    This study developed a reliable procedure to assess the carbon dioxide (CO 2 ) uptake of concrete by carbonation during the service life of a structure and by the recycling of concrete after demolition. To generalize the amount of absorbable CO 2 per unit volume of concrete, the molar concentration of carbonatable constituents in hardened cement paste was simplified as a function of the unit content of cement, and the degree of hydration of the cement paste was formulated as a function of the water-to-cement ratio. The contribution of the relative humidity, type of finishing material for the concrete surface, and the substitution level of supplementary cementitious materials to the CO 2 diffusion coefficient in concrete was reflected using various correction factors. The following parameters varying with the recycling scenario were also considered: the carbonatable surface area of concrete crusher-runs and underground phenomena of the decreased CO 2 diffusion coefficient and increased CO 2 concentration. Based on the developed procedure, a case study was conducted for an apartment building with a principal wall system and an office building with a Rahmen system, with the aim of examining the CO 2 uptake of each structural element under different exposure environments during the service life and recycling of the building. As input data necessary for the case study, data collected from actual surveys conducted in 2012 in South Korea were used, which included data on the surrounding environments, lifecycle inventory database, life expectancy of structures, and recycling activity scenario. Ultimately, the CO 2 uptake of concrete during a 100-year lifecycle (life expectancy of 40 years and recycling span of 60 years) was estimated to be 15.5%–17% of the CO 2 emissions from concrete production, which roughly corresponds to 18%–21% of the CO 2 emissions from the production of ordinary Portland cement. - Highlights: • CO 2 uptake assessment approach owing to the

  19. CO2 Sink/Source Characteristics in the Tropical Indonesian Seas

    KAUST Repository

    Kartadikaria, Aditya R.

    2015-11-05

    Two distinct CO2 sink/source characteristics are found in the tropical Indonesian seas from the compilation of observed data for the period 1984-2013. The western region persistently emits CO2 to the atmosphere, whereas the eastern region is dynamic and acts either as a small source or sink of CO2 to the atmosphere, depending on sites. The segregation is proximal to the Makassar Strait, which is located over the continental shelf and is one of the main routes of the Indonesian Throughflow (ITF). Lower salinity and higher silicate were found in the western region, suggesting a terrestrial influence in this area. Temperature has a limited influence in controlling different CO2 sink/source characteristics in the west and east. However, an SST change of -2.0°C during La Niña events effectively reduces the pCO2 difference between the atmosphere and surface seawater by 50% compared to normal year conditions. During La Niña events, higher wind speeds double the CO2 flux from the ocean to the atmosphere compared to that of a normal year. In the continental shelf area where the CO2 sink area was found, data of over 29 years show that the seawater pCO2 increased by 0.6-3.8 μatm yr−1. Overall, the seawater pCO2 of the Indonesian Seas is supersaturated relative to the atmosphere by 15.9 ± 8.6 μatm and thus acts as a source of CO2 to the atmosphere. This article is protected by copyright. All rights reserved.

  20. Chemical looping combustion. Fuel conversion with inherent CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Brandvoll, Oeyvind

    2005-07-01

    Chemical looping combustion (CLC) is a new concept for fuel energy conversion with CO2 capture. In CLC, fuel combustion is split into separate reduction and oxidation processes, in which a solid carrier is reduced and oxidized, respectively. The carrier is continuously recirculated between the two vessels, and hence direct contact between air and fuel is avoided. As a result, a stoichiometric amount of oxygen is transferred to the fuel by a regenerable solid intermediate, and CLC is thus a variant of oxy-fuel combustion. In principle, pure CO2 can be obtained from the reduction exhaust by condensation of the produced water vapour. The thermodynamic potential and feasibility of CLC has been studied by means of process simulations and experimental studies of oxygen carriers. Process simulations have focused on parameter sensitivity studies of CLC implemented in 3 power cycles; CLC-Combined Cycle, CLC-Humid Air Turbine and CLC-Integrated Steam Generation. Simulations indicate that overall fuel conversion ratio, oxidation temperature and operating pressure are among the most important process parameters in CLC. A promising thermodynamic potential of CLC has been found, with efficiencies comparable to, - or better than existing technologies for CO2 capture. The proposed oxygen carrier nickel oxide on nickel spinel (NiONiAl) has been studied in reduction with hydrogen, methane and methane/steam as well as oxidation with dry air. It has been found that at atmospheric pressure and temperatures above 600 deg C, solid reduction with dry methane occurs with overall fuel conversion of 92%. Steam methane reforming is observed along with methane cracking as side reactions, yielding an overall selectivity of 90% with regard to solid reduction. If steam is added to the reactant fuel, coking can be avoided. A methodology for long-term investigation of solid chemical activity in a batch reactor is proposed. The method is based on time variables for oxidation. The results for Ni

  1. Estimating CO2 Emission Reduction of Non-capture CO2 Utilization (NCCU) Technology

    International Nuclear Information System (INIS)

    Lee, Ji Hyun; Lee, Dong Woog; Gyu, Jang Se; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo; Choi, Jong Shin

    2015-01-01

    Estimating potential of CO 2 emission reduction of non-capture CO 2 utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of CO 2 contained in the flue gas. For the estimating the CO 2 emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle CO 2 of 100 tons per day was performed, Also for the estimation of the indirect CO 2 reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall CO 2 emission was estimated as 48,862 ton per year based on the energy consumption for the production of NaHCO 3 (7.4 GJ/tNaHCO 3 ). While for the NCCU technology, the direct CO 2 reduction through the CO 2 carbonation was estimated as 36,500 ton per year and the indirect CO 2 reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of CO 2 contained in the flue was energy efficient and could be one of the promising technology for the low CO 2 emission technology.

  2. CO2 content of electricity losses

    International Nuclear Information System (INIS)

    Daví-Arderius, Daniel; Sanin, María-Eugenia; Trujillo-Baute, Elisa

    2017-01-01

    Countries are implementing policies to develop greener energy markets worldwide. In Europe, the ¨2030 Energy and Climate Package¨ asks for further reductions of green house gases, renewable sources integration, and energy efficiency targets. But the polluting intensity of electricity may be different in average than when considering market inefficiencies, in particular losses, and therefore the implemented policy must take those differences into account. Precisely, herein we study the importance in terms of CO2 emissions the extra amount of energy necessary to cover losses. With this purpose we use Spanish market and system data with hourly frequency from 2011 to 2013. Our results show that indeed electricity losses significantly explain CO2 emissions, with a higher CO2 emissions rate when covering losses than the average rate of the system. Additionally, we find that the market closing technologies used to cover losses have a positive and significant impact on CO2 emissions: when polluting technologies (coal or combined cycle) close the market, the impact of losses on CO2 emissions is high compared to the rest of technologies (combined heat and power, renewables or hydropower). To the light of these results we make some policy recommendations to reduce the impact of losses on CO2 emissions. - Highlights: • Electricity losses significantly explain CO2 emissions. • Policies aimed to reducing losses have a positive impact on CO2 emissions. • The market closing technology used to cover losses have impacts on CO2 emissions. • Pollutant technologies that close the market should be replaced by renewables.

  3. Studies on CO 2 laser marking

    Science.gov (United States)

    Ueda, Masahiro; Saitoh, Yoshikazu; Hachisuka, Hideki; Ishigaki, Hiroyuki; Gokoh, Yukihiro; Mantani, Hiroshi

    The nature of CO 2 laser marking was studied with a view to putting these lasers to practical use in the semiconductor industry. The marking is found to be due to surface spattering rather than burning, which is the main factor in YAG laser marking. The visibility greatly increases by the application of a surface treatment such as marker ink, varnish or poster color. The CO 2 laser may therefore be used in place of the YAG laser, now widely used for marking, with some merits: CO 2 laser marking is cheaper and faster, and in addition there is no danger of injury from irradiating laser light.

  4. Studies on CO2 Laser Marking

    OpenAIRE

    UEDA, Masahiro; SAITOH, Yoshikazu; HACHISUKA, Hideki; ISHIGAKI, Hiroyuki; GOKOH, Yukihiro; MANTANI, Hiroshi

    1989-01-01

    The nature of CO2 laser marking was studied with a view to putting these lasers to practical use in the semiconductor industry. The marking is found to be due to surface spattering rather than burning, which is the main factor in YAG laser marking. The visibility greatly increases by the application of a surface treatment such as marker ink, varnish or poster color. The CO2 laser may therefore be used in place of the YAG laser, now widely used for marking, with some merits: CO2 laser marki...

  5. The Idea of Global CO2 Trade

    DEFF Research Database (Denmark)

    Svendsen, Gert Tinggaard

    1998-01-01

    -effective control which can solve future global environmental problems. The gains from CO2 trade may give vital financial subsidies from the EU to Eastern Europe, for example, and it will probably not pay to cheat if quotas are renewed periodically by the UN. Cheating countries are then to be excluded from further......The US has been criticized for wanting to earn a fortune on a global CO2 market. However, compared to the situation without trade and provided that such a market is designed so that it does not pay to cheat, a global CO2 market may provide the world with an epoch-making means of cost...

  6. Detection of seismic phases by wavelet transform. Dependence of its performance on wavelet functions; Wavelet henkan ni yoru jishinha no iso kenshutsu. Wavelet ni yoru sai

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X.; Yamazaki, K. [Tokyo Gakugei University, Tokyo (Japan); Oguchi, Y. [Hosei University, Tokyo (Japan)

    1997-10-22

    A study has been performed on wavelet analysis of seismic waves. In the wavelet analysis of seismic waves, there is a possibility that the results according to different wavelet functions may come out with great difference. The study has carried out the following analyses: an analysis of amplitude and phase using wavelet transform which uses wavelet function of Morlet on P- and S-waves generated by natural earthquakes and P-wave generated by an artificial earthquake, and an analysis using continuous wavelet transform, which uses a constitution of complex wavelet function constructed by a completely diagonal scaling function of Daubechies and the wavelet function. As a result, the following matters were made clear: the result of detection of abnormal components or discontinuity depends on the wavelet function; if the Morlet wavelet function is used to properly select angular frequency and scale, equiphase lines in a phase scalogram concentrate on the discontinuity; and the result of applying the complex wavelet function is superior to that of applying the wavelet function of Morlet. 2 refs., 5 figs.

  7. Equilibration of metabolic CO2 with preformed CO2 and bicarbonate

    International Nuclear Information System (INIS)

    Hems, R.; Saez, G.T.

    1983-01-01

    Entry of metabolic 14 CO 2 into urea is shown to occur more readily than it equilibrates with the general pool of cellular plus extracellular bicarbonate plus CO 2 . Since the sites of CO 2 production (pyruvate dehydrogenase and oxoglutarate dehydrogenase) and of fixation (carbamoylphosphate synthetase) are intramitochondrial, it is likely that the fixation of CO 2 is also more rapid than its equilibration with the cytoplasmic pool of bicarbonate plus CO 2 . This observation may point to a more general problem concerning the interpretation of isotope data, with compartmentation or proximity of sites of production and utilisation of metabolites may result in the isotope following a preferred pathway. (Auth.)

  8. Photocatalytic Conversion of CO2 on Mars

    Science.gov (United States)

    Meier, Annie; Hare, Bryan

    2016-01-01

    Light on Mars shows potential for providing the energy means necessary for enhanced In-Situ Resource Utilization (ISRU). Through photocatalysis, the energy barrier required to convert CO2 is lowered and CH4 production is favorable.

  9. Policy Options for Reducing CO2 Emissions

    National Research Council Canada - National Science Library

    Bogusz, Christine; Howlett, Christian

    2008-01-01

    .... Reducing that risk would require restraining the growth of CO2 emissions and ultimately limiting those emissions to a level that would stabilize atmospheric concentrations which would involve costs...

  10. Sustainable Process Networks for CO2 Conversion

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Kongpanna, P.; Pavarajam, V.

    , such as methanol (MeOH) have the largest market, this network will include a variety of thermodynamically feasible conversion paths [4]. From reviews of work previously done, there are ranges of possible products that are formed from CO2 and another co-reactant directly. Methanol, dimethyl ether, dimethyl...... the emissions is the conversion of CO2 into useful products, such as methanol [3]. In this work, through a computer-aided framework for process network synthesis-design, a network of feasible conversion processes that all use emitted CO2 is investigated. CO2 is emitted into the environment from various sources......: power generation, industrial processes, transportation and commercial processes. Within these there are high-purity emissions and low-purity emissions. Rather than sending these to the atmosphere, it is possible to collect them and use them for other purposes. In this work, the first step is determining...

  11. CO2 emissions in the steel industry

    Directory of Open Access Journals (Sweden)

    M. Kundak

    2009-07-01

    Full Text Available Global CO2 emissions caused by the burning of fossil fuels over the past century are presented. Taking into consideration the total world production of more than 1,3 billion tons of steel, the steel industry produces over two billion tons of CO2. Reductions in CO2 emissions as a result of technological improvements and structural changes in steel production in industrialized countries during the past 40 years are described. Substantial further reductions in those emissions will not be possible using conventional technologies. Instead, a radical cutback may be achieved if, instead of carbon, hydrogen is used for direct iron ore reduction. The cost and the ensuing CO2 generation in the production of hydrogen as a reducing agent from various sources are analysed.

  12. CO2 Washout Capability with Breathing Manikin

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon Dioxide (CO2) Washout performance is a critical parameter needed to ensure proper and sufficient designs in a spacesuit and in vehicle applications such as...

  13. Capture and geological storage of CO2

    International Nuclear Information System (INIS)

    2013-03-01

    Capture and geological storage of CO 2 could be a contribution to reduce CO 2 emissions, and also a way to meet the factor 4 objective of reduction of greenhouse gas emissions. This publication briefly presents the capture and storage definitions and principles, and comments some key data related to CO 2 emissions, and their natural trapping by oceans, soils and forests. It discusses strengths (a massive and perennial reduction of CO 2 emissions, a well defined regulatory framework) and weaknesses (high costs and uncertain cost reduction perspectives, a technology which still consumes a lot of energy, geological storage capacities still to be determined, health environmental impacts and risks to be controlled, a necessary consultation of population for planned projects) of this option. Actions undertaken by the ADEME are briefly reviewed

  14. Thermodynamic modeling of CO2 mixtures

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel

    Knowledge of the thermodynamic properties and phase equilibria of mixtures containing carbon dioxide (CO2) is important in several industrial processes such as enhanced oil recovery, carbon capture and storage, and supercritical extractions, where CO2 is used as a solvent. Despite this importance......, accurate predictions of the thermodynamic properties and phase equilibria of mixtures containing CO2 are challenging with classical models such as the Soave-Redlich-Kwong (SRK) equation of state (EoS). This is believed to be due to the fact, that CO2 has a large quadrupole moment which the classical models...... and with or without introducing an additional pure compound parameter. In the absence of quadrupolar compounds qCPA reduces to CPA, which itself reduces toSRK in the absence of association. As the number of adjustable parameters in thermodynamic models increase, the parameter estimation problem becomes increasingly...

  15. The ATLAS IBL CO2 Cooling System

    CERN Document Server

    Verlaat, Bartholomeus; The ATLAS collaboration

    2016-01-01

    The Atlas Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity. This paper describes the design, development, construction and commissioning of the IBL CO2 cooling system. It describes the challenges overcome and the important lessons learned for the development of future systems which are now under design for the Phase-II upgrade detectors.

  16. Natural Analogues of CO2 Geological Storage

    International Nuclear Information System (INIS)

    Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2007-01-01

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  17. Pulmonary CO2 elimination during surgical procedures using intra- or extraperitoneal CO2 insufflation.

    Science.gov (United States)

    Mullett, C E; Viale, J P; Sagnard, P E; Miellet, C C; Ruynat, L G; Counioux, H C; Motin, J P; Boulez, J P; Dargent, D M; Annat, G J

    1993-03-01

    We examined end-tidal CO2 tension (PETCO2) and pulmonary CO2 elimination of CO2 (VECO2) during CO2 insufflation under general anesthesia for three surgical procedures: gynecologic laparoscopy (intraperitoneal CO2 insufflation for 43 +/- 4 min), laparoscopic cholecystectomy (intraperitoneal CO2 insufflation for 125 +/- 14 min), and pelviscopy (extraperitoneal CO2 insufflation for 45 +/- 3 min). All patients (10 in each group) underwent controlled mechanical ventilation. Oxygen consumption (VO2) and VECO2 were measured at 2-min intervals by a system using a mass spectrometer. For the three surgical procedures, VO2 remained stable, whereas VECO2 and PETCO2 increased in parallel from the 8th to the 10th min after the start of CO2 insufflation. A plateau was reached 10 min later in patients having intraperitoneal insufflation, whereas VECO2 and PETCO2 continued to increase slowly throughout CO2 insufflation during pelviscopy. During pelviscopy, the maximum increase in VECO2 and PETCO2 (76 +/- 5% and 71 +/- 7%) was significantly more pronounced than that observed during cholecystectomy (25 +/- 4% and 25 +/- 4%) and gynecologic laparoscopy (15 +/- 3% and 12 +/- 2%). The authors conclude that CO2 diffusion into the body is more marked during extraperitoneal than during intraperitoneal CO2 insufflation but is not influenced markedly by the duration of intraperitoneal insufflation.

  18. CO2 Sensing and CO2 Regulation of Stomatal Conductance: Advances and Open Questions.

    Science.gov (United States)

    Engineer, Cawas B; Hashimoto-Sugimoto, Mimi; Negi, Juntaro; Israelsson-Nordström, Maria; Azoulay-Shemer, Tamar; Rappel, Wouter-Jan; Iba, Koh; Schroeder, Julian I

    2016-01-01

    Guard cells form epidermal stomatal gas-exchange valves in plants and regulate the aperture of stomatal pores in response to changes in the carbon dioxide (CO2) concentration ([CO2]) in leaves. Moreover, the development of stomata is repressed by elevated CO2 in diverse plant species. Evidence suggests that plants can sense [CO2] changes via guard cells and via mesophyll tissues in mediating stomatal movements. We review new discoveries and open questions on mechanisms mediating CO2-regulated stomatal movements and CO2 modulation of stomatal development, which together function in the CO2 regulation of stomatal conductance and gas exchange in plants. Research in this area is timely in light of the necessity of selecting and developing crop cultivars that perform better in a shifting climate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Udvikling af CO2 neutralt byrumsarmatur

    DEFF Research Database (Denmark)

    Poulsen, Peter Behrensdorff; Dam-Hansen, Carsten; Corell, Dennis Dan

    Denne rapport indeholder en beskrivelse af arbejdet udført i og resultaterne af forsknings- og udviklingsprojektet ” Udvikling af CO2 neutralt byrumsarmatur” og udgør slutrapportering for dette projekt.......Denne rapport indeholder en beskrivelse af arbejdet udført i og resultaterne af forsknings- og udviklingsprojektet ” Udvikling af CO2 neutralt byrumsarmatur” og udgør slutrapportering for dette projekt....

  20. Combustion of hythane diluted with CO2

    Directory of Open Access Journals (Sweden)

    Hraiech Ibtissem

    2015-01-01

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

  1. Membraneless water filtration using CO2

    OpenAIRE

    Shin, Sangwoo; Shardt, Orest; Warren, Patrick B.; Stone, Howard A.

    2017-01-01

    Water purification technologies such as microfiltration/ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO2. Dissolution of CO2 into the suspension creates solute gradients that drive phoreti...

  2. Flow assurance studies for CO2 transport

    OpenAIRE

    Veltin, J.; Belfroid, S.P.C.

    2013-01-01

    In order to compensate for the relative lack of experience of the CCTS community, Flow Assurance studies of new CO2 pipelines and networks are a very important step toward reliable operation. This report details a typical approach for Flow Assurance study of CO2 transport pipeline. Considerations to take during the design of a pipeline are highlighted, with an emphasis on operability of the system. The steady state aspects of a pipeline operation are first addressed, putting some highlight in...

  3. Anthropogenic CO2 in the ocean

    Directory of Open Access Journals (Sweden)

    Tsung-Hung Peng

    2005-06-01

    Full Text Available The focus of this review article is on the anthropogenic CO2 taken up by the ocean. There are several methods of identifying the anthropogenic CO2 signal and quantifying its inventory in the ocean. The ?C* method is most frequently used to estimate the global distribution of anthropogenic CO2 in the ocean. Results based on analysis of the dataset obtained from the comprehensive surveys of inorganic carbon distribution in the world oceans in the 1990s are given. These surveys were jointly conducted during the World Ocean Circulation Experiment (WOCE and the Joint Global Ocean Flux Study (JGOFS. This data set consists of 9618 hydrographic stations from a total of 95 cruises, which represents the most accurate and comprehensive view of the distribution of inorganic carbon in the global ocean available today. The increase of anthropogenic CO2 in the ocean during the past few decades is also evaluated using direct comparison of results from repeat surveys and using statistical method of Multi-parameter Linear Regression (MLR. The impact of increasing oceanic anthropogenic CO2 on the calcium carbonate system in the ocean is reviewed briefly as well. Extensive studies of CaCO3 dissolution as a result of increasing anthropogenic CO2 in the ocean have revealed several distinct oceanic regions where the CaCO3 undersaturation zone has expanded.

  4. CO2 efflux from cleared mangrove peat.

    Directory of Open Access Journals (Sweden)

    Catherine E Lovelock

    Full Text Available BACKGROUND: CO(2 emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. METHODOLOGY/PRINCIPAL FINDINGS: We measured CO(2 efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO(2 efflux. CO(2 efflux from soils declines from time of clearing from ∼10,600 tonnes km(-2 year(-1 in the first year to 3000 tonnes km(2 year(-1 after 20 years since clearing. Disturbing peat leads to short term increases in CO(2 efflux (27 umol m(-2 s(-1, but this had returned to baseline levels within 2 days. CONCLUSIONS/SIGNIFICANCE: Deforesting mangroves that grow on peat soils results in CO(2 emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks.

  5. Density of aqueous solutions of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Julio E.

    2001-10-10

    In this report, we present a numerical representation for the partial molar volume of CO2 in water and the calculation of the corresponding aqueous solution density. The motivation behind this work is related to the importance of having accurate representations for aqueous phase properties in the numerical simulation of carbon dioxide disposal into aquifers as well as in geothermal applications. According to reported experimental data the density of aqueous solutions of CO2 can be as much as 2-3% higher than pure water density. This density variation might produce an influence on the groundwater flow regime. For instance, in geologic sequestration of CO2, convective transport mixing might occur when, several years after injection of carbon dioxide has stopped, the CO2-rich gas phase is concentrated at the top of the formation, just below an overlaying caprock. In this particular case the heavier CO2 saturated water will flow downward and will be replaced by water with a lesser CO2 content.

  6. Abatement of CO2 emissions: IFP's solutions

    International Nuclear Information System (INIS)

    2003-01-01

    In a context of increasing energy consumption and world economic growth, the fight against greenhouse gases has become a major technological challenge for the coming years. The capture and sequestration of CO 2 in the underground is a promising solution in terms of environmental impact, especially in places and sectors characterized by a strong concentration of CO 2 emissions (power generation plants, big industries). However, such a solution requires important R and D efforts to reduce the costs and warrant the long-term reliability of the storage. The French institute of petroleum (IFP) will play an important role in the implementation of the geological sequestration. This press kit comprises 7 documents: a press release from November 4, 2003; a press conference with a series of slides presenting the stakes, solutions and actions proposed by the IFP in collaboration with several foreign partners (CO 2 capture, storage in depleted hydrocarbon deposits, saline aquifers or abandoned coal seams, storage potential, reduction of costs); a summary of the stakes and solutions for CO 2 sequestration in deep underground; a similar document presented at the Panorama 2003 colloquium; the CO 2 constraint in France and in Europe (international consensus on climatic change, Kyoto protocol, European directive about tradable carbon permits, voluntary commitment of companies in the fight against greenhouse effects (AERES)); the European project Castor (CO 2 from capture to storage); and the IFP brochure 'innovating for a sustainable development in the energy domain'. (J.S.)

  7. How much CO2 is trapped in carbonate minerals of a natural CO2 occurrence?

    Science.gov (United States)

    Király, Csilla; Szabó, Zsuzsanna; Szamosfalvi, Ágnes; Cseresznyés, Dóra; Király, Edit; Szabó, Csaba; Falus, György

    2017-04-01

    Carbon Capture and Storage (CCS) is a transitional technology to decrease CO2 emissions from human fossil fuel usage and, therefore, to mitigate climate change. The most important criteria of a CO2 geological storage reservoir is that it must hold the injected CO2 for geological time scales without its significant seepage. The injected CO2 undergoes physical and chemical reactions in the reservoir rocks such as structural-stratigraphic, residual, dissolution or mineral trapping mechanisms. Among these, the safest is the mineral trapping, when carbonate minerals such as calcite, ankerite, siderite, dolomite and dawsonite build the CO2 into their crystal structures. The study of natural CO2 occurrences may help to understand the processes in CO2 reservoirs on geological time scales. This is the reason why the selected, the Mihályi-Répcelak natural CO2 occurrence as our research area, which is able to provide particular and highly significant information for the future of CO2 storage. The area is one of the best known CO2 fields in Central Europe. The main aim of this study is to estimate the amount of CO2 trapped in the mineral phase at Mihályi-Répcelak CO2 reservoirs. For gaining the suitable data, we apply petrographic, major and trace element (microprobe and LA-ICP-MS) and stable isotope analysis (mass spectrometry) and thermodynamic and kinetic geochemical models coded in PHREEQC. Rock and pore water compositions of the same formation, representing the pre-CO2 flooding stages of the Mihályi-Répcelak natural CO2 reservoirs are used in the models. Kinetic rate parameters are derived from the USGS report of Palandri and Kharaka (2004). The results of petrographic analysis show that a significant amount of dawsonite (NaAlCO3(OH)2, max. 16 m/m%) precipitated in the rock due to its reactions with CO2 which flooded the reservoir. This carbonate mineral alone traps about 10-30 kg/m3 of the reservoir rock from the CO2 at Mihályi-Répcelak area, which is an

  8. Experimental Ion Mobility measurements in Ne-CO2 and CO2-N2 mixtures

    International Nuclear Information System (INIS)

    Encarnação, P.M.C.C.; Cortez, A.F.V.; Santos, F.P.; Trindade, A.M.F.; Borges, F.I.G.M.; Conde, C.A.N.; Veenhof, R.; Neves, P.N.B.

    2016-01-01

    In this paper we present the experimental results for the mobility, K 0 , of ions in neon-carbon dioxide (Ne-CO 2 ) and carbon dioxide-nitrogen (CO 2 -N 2 ) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO 2 mixture only one peak was observed for CO 2 concentrations above 25%, which has been identified as an ion originated in CO 2 , while below 25% of CO 2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm 2 V −1 s −1 in the 10%-99% interval of CO 2 , and from 4.61 ± 0.19 to 3.00 ± 0.09 cm 2 V −1 s −1 for the second peak observed (10%–25% of CO 2 ). For the CO 2 -N 2 , the time-of-arrival spectra displayed only one peak for CO 2 concentrations above 10%, which was attributed to ions originated in CO 2 , namely CO 2 + (CO 2 ), with a second peak appearing for CO 2 concentrations below 10%. This second peak, with higher mobility, was attributed to CO 2 + ions. The mobility values of the main peak range between 2.11 ± 0.04 and 1.10 ± 0.03 cm 2 V −1 s −1 in the 1%–99% interval of CO 2 , while the second peak's from 2.26 ± 0.02 and 1.95 ± 0.04 cm 2 V −1 s −1 (1%–10% of CO 2 ). The inverse of the mobility displays an aproximately linear dependence on the CO 2 concentration in the mixture.

  9. Nepenthes pitchers are CO2-enriched cavities, emit CO2to attract preys.

    Science.gov (United States)

    Baby, Sabulal; Johnson, Anil John; Zachariah, Elavinamannil Jacob; Hussain, Abdul Azeez

    2017-09-12

    Carnivorous plants of the genus Nepenthes supplement their nutrient deficiency by capturing arthropods or by mutualistic interactions, through their leaf-evolved biological traps (pitchers). Though there are numerous studies on these traps, mostly on their prey capture mechanisms, the gas composition inside them remains unknown. Here we show that, Nepenthes unopened pitchers are CO 2 -enriched 'cavities', when open they emit CO 2 , and the CO 2 gradient around open pitchers acts as a cue attracting preys towards them. CO 2 contents in near mature, unopened Nepenthes pitchers were in the range 2500-5000 ppm. Gas collected from inside open N. khasiana pitchers showed CO 2 at 476.75 ± 59.83 ppm. CO 2 -enriched air-streaming through N. khasiana pitchers (at 619.83 ± 4.53 ppm) attracted (captured) substantially higher number of aerial preys compared to air-streamed pitchers (CO 2 at 412.76 ± 4.51 ppm). High levels of CO 2 dissolved in acidic Nepenthes pitcher fluids were also detected. We demonstrate respiration as the source of elevated CO 2 within Nepenthes pitchers. Most unique features of Nepenthes pitchers, viz., high growth rate, enhanced carbohydrate levels, declined protein levels, low photosynthetic capacity, high respiration rate and evolved stomata, are influenced by the CO 2 -enriched environment within them.

  10. Primary, secondary, and tertiary amines for CO2 capture: designing for mesoporous CO2 adsorbents.

    Science.gov (United States)

    Ko, Young Gun; Shin, Seung Su; Choi, Ung Su

    2011-09-15

    CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket". Copyright © 2011. Published by Elsevier Inc.

  11. Modeling CO2 Gas Migration of Shallow Subsurface CO2 Leakage Experiments

    Science.gov (United States)

    Porter, M. L.; Plampin, M. R.; Pawar, R.; Illangasekare, T. H.

    2013-12-01

    Leakage of injected CO2 into shallow subsurface aquifers or back into the atmosphere at geologic carbon sequestration sites is a risk that must be minimized. One potential CO2 leakage pathway involves the transport of dissolved CO2 into a shallow aquifer where the CO2 exsolves, forming a free CO2 gas phase that subsequently migrates through the aquifer. In order to reduce the negative effects of CO2 exsolution, it is important to fully understand each of the processes controlling the movement CO2, as well as the effects of aquifer heterogeneity on the overall fate and transport of CO2. In this work, we present multiphase flow simulations of intermediate scale CO2 exsolution experiments. The multiphase flow simulations were carried out using the Finite Element Heat and Mass Transfer code (FEHM) developed at Los Alamos National Laboratory. Simulations were first designed to model experiments conducted in two different homogeneous packed sands. PEST (Parameter Estimation and Uncertainty Analysis) was used to optimize multiphase flow parameters (i.e., porosity, permeability, relative permeability, and capillary pressure) within FEHM. The optimized parameters were subsequently used to model heterogeneous experiments consisting of various packing configurations using the same sands. Comparisons of CO2 saturation between experiments and simulations will be presented and analyzed.

  12. Combining CO2 reduction with propane oxidative dehydrogenation over bimetallic catalysts.

    Science.gov (United States)

    Gomez, Elaine; Kattel, Shyam; Yan, Binhang; Yao, Siyu; Liu, Ping; Chen, Jingguang G

    2018-04-11

    The inherent variability and insufficiencies in the co-production of propylene from steam crackers has raised concerns regarding the global propylene production gap and has directed industry to develop more on-purpose propylene technologies. The oxidative dehydrogenation of propane by CO 2 (CO 2 -ODHP) can potentially fill this gap while consuming a greenhouse gas. Non-precious FeNi and precious NiPt catalysts supported on CeO 2 have been identified as promising catalysts for CO 2 -ODHP and dry reforming, respectively, in flow reactor studies conducted at 823 K. In-situ X-ray absorption spectroscopy measurements revealed the oxidation states of metals under reaction conditions and density functional theory calculations were utilized to identify the most favorable reaction pathways over the two types of catalysts.

  13. Carbon Dioxide, Hydrographic and Chemical Data Obtained During the Nine R/V Knorr Cruises Comprising the Indian Ocean CO2 Survey (WOCE Sections I8SI9S, I9N, I8NI5E, I3, I5WI4, I7N, I1, I10, and I2; December 1, 1994 - January 22, 1996) (NODC Accession 0115009)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115009 includes chemical, discrete sample, physical and profile data collected from R/V Knorr Cruises Comprising the Indian Ocean CO2 Survey (WOCE...

  14. CO2-Water-Rock Wettability: Variability, Influencing Factors, and Implications for CO2Geostorage.

    Science.gov (United States)

    Iglauer, Stefan

    2017-05-16

    Carbon geosequestration (CGS) has been identified as a key technology to reduce anthropogenic greenhouse gas emissions and thus significantly mitigate climate change. In CGS, CO 2 is captured from large point-source emitters (e.g., coal fired power stations), purified, and injected deep underground into geological formations for disposal. However, the CO 2 has a lower density than the resident formation brine and thus migrates upward due to buoyancy forces. To prevent the CO 2 from leaking back to the surface, four trapping mechanisms are used: (1) structural trapping (where a tight caprock acts as a seal barrier through which the CO 2 cannot percolate), (2) residual trapping (where the CO 2 plume is split into many micrometer-sized bubbles, which are immobilized by capillary forces in the pore network of the rock), (3) dissolution trapping (where CO 2 dissolves in the formation brine and sinks deep into the reservoir due to a slight increase in brine density), and (4) mineral trapping (where the CO 2 introduced into the subsurface chemically reacts with the formation brine or reservoir rock or both to form solid precipitates). The efficiency of these trapping mechanisms and the movement of CO 2 through the rock are strongly influenced by the CO 2 -brine-rock wettability (mainly due to the small capillary-like pores in the rock which form a complex network), and it is thus of key importance to rigorously understand CO 2 -wettability. In this context, a substantial number of experiments have been conducted from which several conclusions can be drawn: of prime importance is the rock surface chemistry, and hydrophilic surfaces are water-wet while hydrophobic surfaces are CO 2 -wet. Note that CO 2 -wet surfaces dramatically reduce CO 2 storage capacities. Furthermore, increasing pressure, salinity, or dissolved ion valency increases CO 2 -wettability, while the effect of temperature is not well understood. Indeed theoretical understanding of CO 2 -wettability and the

  15. Economic efficiency of CO2 reduction programs

    International Nuclear Information System (INIS)

    Tahvonen, O.; Storch, H. von; Storch, J. von

    1993-01-01

    A highly simplified time-dependent low-dimensional system has been designed to describe conceptually the interaction of climate and economy. Enhanced emission of carbon dioxide (CO 2 ) is understood as the agent that not only favors instantaneous consumption but also causes unfavorable climate changes at a later time. The problem of balancing these two counterproductive effects of CO 2 emissions on a finite time horizon is considered. The climate system is represented by just two parameters, namely a globally averaged near-surface air-temperature and a globally averaged troposheric CO 2 concentration. The costs of abating CO 2 emissions are monitored by a function which depends quadratically on the percentage reduction of emission compared to an 'uncontrolled emission' scenario. Parameters are fitted to historical climate data and to estimates from studies of CO 2 abatement costs. Two optimization approaches, which differ from earlier attempts to describe the interaction of economy and climate, are discussed. In the 'cost oriented' strategy an optimal emission path is identified which balances the abatement costs and explicitly formulated damage costs. These damage costs, whose estimates are very uncertain, are hypothesized to be a linear function of the time-derivative of temperature. In the 'target oriented' strategy an emission path is chosen so that the abatement costs are minimal while certain restrictions on the terminal temperature and concentration change are met. (orig.)

  16. Rangeland -- plant response to elevated CO2

    International Nuclear Information System (INIS)

    Owensby, C.E.; Coyne, P.I.; Ham, J.M.; Parton, W.; Rice, C.; Auen, L.M.; Adam, N.

    1993-01-01

    Plots of a tallgrass prairie ecosystem were exposed to ambient and twice-ambient CO 2 concentrations in open-top chambers and compared to unchambered ambient CO 2 plots during the entire growing season from 1989 through 1992. Relative root production among treatments was estimated using root ingrowth bags which remained in place throughout the growing season. Latent heat flux was simulated with and without water stress. Botanical composition was estimated annuallyin all treatments. Open-top chambers appeared to reduce latent heat flux and increase water use efficiency similar to elevated CO 2 when water stress was not severe, but under severe water stress, chamber effect on water use efficiency was limited. In natural ecosystems with periodic moisture stress, increased water use efficiency under elevated CO 2 apparently would have a greater impact on productivity than photosynthetic pathway. Root ingrowth biomass was greater in 1990 and 1991 on elevated CO 2 plots compared to ambient or chambered-ambient plots. In 1992, there was no difference in root ingrowth biomass among treatments

  17. CO2 and CO Simulations and Their Source Signature Indicated by CO/CO2

    Science.gov (United States)

    Kawa, Randy; Huisheng, Bian

    2004-01-01

    Three years (2000-2002) atmospheric CO2 and CO fields are simulated by a Chemistry Transport Model driven by the assimilated meteorological fields from GEOS-4. The simulated CO2 and CO are evaluated by measurements from surface (CMDL), satellite (MOPITT/CO), and aircraft. The model-observation comparisons indicate reasonable agreement in both source and remote regions, and in the lower and upper troposphere. The simulation also captures the seasonality of CO2 and CO variations. The ratios of CO/CO2 are analyzed over different representative regions to identify the source signature, since the anthropogenic CO comes fiom the same combustion processes as CO2. This work enables us to improve satellite inversion estimates of CO2 sources and sinks by simultaneously using satellite CO measurement.

  18. CO2-Switchable Membranes Prepared by Immobilization of CO2-Breathing Microgels.

    Science.gov (United States)

    Zhang, Qi; Wang, Zhenwu; Lei, Lei; Tang, Jun; Wang, Jianli; Zhu, Shiping

    2017-12-20

    Herein, we report the development of a novel CO 2 -responsive membrane system through immobilization of CO 2 -responsive microgels into commercially available microfiltration membranes using a method of dynamic adsorption. The microgels, prepared from soap-free emulsion polymerization of CO 2 -responsive monomer 2-(diethylamino)ethyl methacrylate (DEA), can be reversibly expanded and shrunken upon CO 2 /N 2 alternation. When incorporated into the membranes, this switching behavior was preserved and further led to transformation between microfiltration and ultrafiltration membranes, as indicated from the dramatic changes on water flux and BSA rejection results. This CO 2 -regulated performance switching of membranes was caused by the changes of water transportation channel, as revealed from the dynamic water contact angle tests and SEM observation. This work represents a simple yet versatile strategy for making CO 2 -responsive membranes.

  19. CO2 sensing and CO2 regulation of stomatal conductance: advances and open questions

    Science.gov (United States)

    Engineer, Cawas; Hashimoto-Sugimoto, Mimi; Negi, Juntaro; Israelsson-Nordstrom, Maria; Azoulay-Shemer, Tamar; Rappel, Wouter-Jan; Iba, Koh; Schroeder, Julian

    2015-01-01

    Guard cells form epidermal stomatal gas exchange valves in plants and regulate the aperture of stomatal pores in response to changes in the carbon dioxide (CO2) concentration in leaves. Moreover, the development of stomata is repressed by elevated CO2 in diverse plant species. Evidence suggests that plants can sense CO2 concentration changes via guard cells and via mesophyll tissues in mediating stomatal movements. We review new discoveries and open questions on mechanisms mediating CO2-regulated stomatal movements and CO2 modulation of stomatal development, which together function in CO2-regulation of stomatal conductance and gas exchange in plants. Research in this area is timely in light of the necessity of selecting and developing crop cultivars which perform better in a shifting climate. PMID:26482956

  20. Effective CO2 lifetime and future CO2 levels based on fit function

    Directory of Open Access Journals (Sweden)

    G. R. Sonnemann

    2013-09-01

    Full Text Available The estimated global CO2 emission rates and the measured atmospheric CO2 concentrations show that only a certain share of the emitted CO2 accumulates in the atmosphere. For given atmospheric emissions of CO2, the effective lifetime determines its accumulation in the atmosphere and, consequently, its impact on the future global warming. We found that on average the inferred effective lifetime of CO2 decreases as its atmospheric concentration increases, reducing the rate of its accumulation in the atmosphere. We derived a power function that fits the varying lifetimes. Based on this fitting function, we calculated the increase of CO2 for different scenarios of future global emission rates.

  1. CO2-based hydrogen storage: CO2 hydrogenation to formic acid, formaldehyde and methanol

    Science.gov (United States)

    Schaub, Thomas

    2018-02-01

    The storage of hydrogen via hydrogenation of CO2 to small organic molecules can be attractive for mobile applications. In this article, the state of the art regarding hydrogen storage in Methanol, Formic Acid as well as Formaldehyde and derivates based on CO2 hydrogenation is summarized. The reverse reaction, the release of hydrogen from these molecules is also crucial and described in the articles together with possible concepts for the use of hydrogen storage by CO2 hydrogenation.

  2. Behavior of CO2/water flow in porous media for CO2geological storage.

    Science.gov (United States)

    Jiang, Lanlan; Yu, Minghao; Liu, Yu; Yang, Mingjun; Zhang, Yi; Xue, Ziqiu; Suekane, Tetsuya; Song, Yongchen

    2017-04-01

    A clear understanding of two-phase fluid flow properties in porous media is of importance to CO 2 geological storage. The study visually measured the immiscible and miscible displacement of water by CO 2 using MRI (magnetic resonance imaging), and investigated the factor influencing the displacement process in porous media which were filled with quartz glass beads. For immiscible displacement at slow flow rates, the MR signal intensity of images increased because of CO 2 dissolution; before the dissolution phenomenon became inconspicuous at flow rate of 0.8mLmin -1 . For miscible displacement, the MR signal intensity decreased gradually independent of flow rates, because supercritical CO 2 and water became miscible in the beginning of CO 2 injection. CO 2 channeling or fingering phenomena were more obviously observed with lower permeable porous media. Capillary force decreases with increasing particle size, which would increase permeability and allow CO 2 and water to invade into small pore spaces more easily. The study also showed CO 2 flow patterns were dominated by dimensionless capillary number, changing from capillary finger to stable flow. The relative permeability curve was calculated using Brooks-Corey model, while the results showed the relative permeability of CO 2 slightly decreases with the increase of capillary number. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Evasion of CO2 injected into the ocean in the context of CO2 stabilization

    International Nuclear Information System (INIS)

    Kheshgi, Haroon S.

    2004-01-01

    The eventual evasion of injected CO 2 to the atmosphere is one consideration when assessing deep-sea disposal of CO 2 as a potential response option to climate change concerns. Evasion estimated using an ocean carbon cycle model is compared to long-term trajectories for future CO 2 emissions, including illustrative cases leading to stabilization of CO 2 concentration at various levels. Modeled residence time for CO 2 injected into the deep ocean exceeds the 100-year time-scale usually considered in scenarios for future emissions, and the potential impacts of climate change. Illustrative cases leading monotonically to constant CO 2 concentration have been highlighted by the Intergovernmental Panel on Climate Change to give guidance on possible timing of emission reductions that may be required to stabilize greenhouse gas concentrations at various levels. For stabilization cases considered, significant modeled evasion does not occur until long after CO 2 emissions have reached a maximum and begun to decline. Illustrative cases can also lead to a maximum in CO 2 concentration followed by a decline to slowly decreasing concentrations. In such cases, future injection of emissions into the deep ocean leads to lower maximum CO 2 concentration, with less effect on concentration later on in time

  4. Effect of Uncertainties in CO2 Property Databases on the S-CO2 Compressor Performance

    International Nuclear Information System (INIS)

    Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu; Cha, Je Eun

    2013-01-01

    Various S-CO 2 Brayton cycle experiment facilities are on the state of construction or operation for demonstration of the technology. However, during the data analysis, S-CO 2 property databases are widely used to predict the performance and characteristics of S-CO 2 Brayton cycle. Thus, a reliable property database is very important before any experiment data analyses or calculation. In this paper, deviation of two different property databases which are widely used for the data analysis will be identified by using three selected properties for comparison, C p , density and enthalpy. Furthermore, effect of above mentioned deviation on the analysis of test data will be briefly discussed. From this deviation, results of the test data analysis can have critical error. As the S-CO 2 Brayton cycle researcher knows, CO 2 near the critical point has dramatic change on thermodynamic properties. Thus, it is true that a potential error source of property prediction exists in CO 2 properties near the critical point. During an experiment data analysis with the S-CO 2 Brayton cycle experiment facility, thermodynamic properties are always involved to predict the component performance and characteristics. Thus, construction or defining of precise CO 2 property database should be carried out to develop Korean S-CO 2 Brayton cycle technology

  5. The Abundance of Atmospheric CO_2 in Ocean Exoplanets: a Novel CO_2 Deposition Mechanism

    International Nuclear Information System (INIS)

    Levi, A.; Sasselov, D.; Podolak, M.

    2017-01-01

    We consider super-Earth sized planets which have a water mass fraction large enough to form an external mantle composed of high-pressure water-ice polymorphs and also lack a substantial H/He atmosphere. We consider such planets in their habitable zone, so that their outermost condensed mantle is a global, deep, liquid ocean. For these ocean planets, we investigate potential internal reservoirs of CO_2, the amount of CO_2 dissolved in the ocean for the various saturation conditions encountered, and the ocean-atmosphere exchange flux of CO_2. We find that, in a steady state, the abundance of CO_2 in the atmosphere has two possible states. When wind-driven circulation is the dominant CO_2 exchange mechanism, an atmosphere of tens of bars of CO_2 results, where the exact value depends on the subtropical ocean surface temperature and the deep ocean temperature. When sea-ice formation, acting on these planets as a CO_2 deposition mechanism, is the dominant exchange mechanism, an atmosphere of a few bars of CO_2 is established. The exact value depends on the subpolar surface temperature. Our results suggest the possibility of a negative feedback mechanism, unique to water planets, where a reduction in the subpolar temperature drives more CO_2 into the atmosphere to increase the greenhouse effect.

  6. Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

    KAUST Repository

    Hengne, Amol Mahalingappa

    2018-04-02

    Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO2) catalysts showed a very high selectivity for methane (99%) during CO2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO2 (5% Ni-5% Sn/ZrO2) showed the rate of methanol formation to be 0.0417 μmol/(gcat·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO2 (5Ni5Sn/10InZrO2) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO2 (0.1043 μmol/(gcat·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO2-temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni28Sn27, Ni18Sn37, and Ni37Sn18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO2 by the H2 reduction process with high methanol selectivity.

  7. The idea of global CO2 trade

    International Nuclear Information System (INIS)

    Svendsen, G.T.

    1999-01-01

    The US has been criticized for wanting to earn a fortune on a global CO 2 market. However, compared to the situation without trade and provided that such a market is designed so that it does not pay to cheat, a global CO 2 market may provide the world with an epoch-making means of cost-effective control which can solve future global environmental problems. The economic gains from 'hot air' distributions of permits and CO 2 trade make the system politically attractive to potential participants. For example, vital financial subsidies from the EU to Eastern Europe are to be expected. It will probably not pay to cheat if quotas are renewed periodically by the UN. Cheating countries are then to be excluded from further profitable trade. Also, a periodical renewal of permits makes it possible to tighten target levels in the future

  8. The Idea of Global CO2 Trade

    DEFF Research Database (Denmark)

    Svendsen, Gert Tinggaard

    1999-01-01

    The US has been criticized for wanting to earn a fortune on a global CO2 market. However, compared to the situation without trade and provided that such a market is designed so that it does not pay to cheat, a global CO2 market may provide the world with an epoch-making means of cost......-effective control which can solve future global environmental problems. The economic gains from 'hot air' distributions of permits and CO2 trade make the system politically attractive to potential participants. For example, vital financial subsidies from the EU to Eastern Europe are to be expected. It will probably...... not pay to cheat if quotas are renewed periodically by the UN. Cheating countries are then to be excluded from further profitable trade. Also, a periodical renewal of permits makes it possible to tighten target levels in the future....

  9. CO2 utilization: Developments in conversion processes

    Directory of Open Access Journals (Sweden)

    Erdogan Alper

    2017-03-01

    The potential utilization of CO2, captured at power plants, should also been taken into consideration for sustainability. This CO2 source, which is potentially a raw material for the chemical industry, will be available at sufficient quality and at gigantic quantity upon realization of on-going tangible capture projects. Products resulting from carboxylation reactions are obvious conversions. In addition, provided that enough supply of energy from non-fossil resources, such as solar [1], is ensured, CO2 reduction reactions can produce several valuable commodity chemicals including multi-carbon compounds, such as ethylene and acrylic acid, in addition to C1 chemicals and polymers. Presently, there are only few developing technologies which can find industrial applications. Therefore, there is a need for concerted research in order to assess the viability of these promising exploratory technologies rationally.

  10. Upscaling of enzyme enhanced CO2 capture

    DEFF Research Database (Denmark)

    Gladis, Arne Berthold

    the mass transfer of CO2 with slow-capturing but energetically favorable solvents can open up a variety of new process options for this technology. The ubiquitous enzyme carbonic anhydrase (CA), which enhances the mass transfer of CO2 in the lungs by catalyzing the reversible hydration of CO2, is one very...... promising mass transfer rate promoter for CCS. This process has been previously been tested successfully in lab scale and in some rare cases in pilot scale, but no validated process model for this technology has been published yet. This PhD thesis presents an investigation of the feasibility of enzyme...... enzyme kinetic model and validating it against in-house pilot plant experiments. The work consisted of identifying a suitable enzyme-solvent system and the ideal process conditions by comparing mass transfer rates of different solvents and enzyme enhanced solvents in a lab scale wetted wall column...

  11. Assessment of CO2 free energy options

    International Nuclear Information System (INIS)

    Cavlina, N.; Raseta, D.; Matutinovic, I.

    2014-01-01

    One of the European Union climate and energy targets is to significantly reduce CO 2 emissions, at least 20% by 2020, compared to 1990. In the power industry, most popular solution is use of solar and wind power. Since their production varies significantly during the day, for the purpose of base-load production they can be paired with gas-fired power plant. Other possible CO 2 -free solution is nuclear power plant. This article compared predicted cost of energy production for newly built nuclear power plant and newly built combination of wind or solar and gas-fired power plant. Comparison was done using Levelized Unit of Energy Cost (LUEC). Calculations were performed using the Monte Carlo method. For input parameters that have biggest uncertainty (gas cost, CO 2 emission fee) those uncertainties were addressed not only through probability distribution around predicted value, but also through different scenarios. Power plants were compared based on their economic lifetime. (authors)

  12. Membraneless water filtration using CO2.

    Science.gov (United States)

    Shin, Sangwoo; Shardt, Orest; Warren, Patrick B; Stone, Howard A

    2017-05-02

    Water purification technologies such as microfiltration/ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO 2 . Dissolution of CO 2 into the suspension creates solute gradients that drive phoretic motion of particles. Due to the large diffusion potential generated by the dissociation of carbonic acid, colloidal particles move either away from or towards the gas-liquid interface depending on their surface charge. Using the directed motion of particles induced by exposure to CO 2 , we demonstrate a scalable, continuous flow, membraneless particle filtration process that exhibits low energy consumption, three orders of magnitude lower than conventional microfiltration/ultrafiltration processes, and is essentially free from fouling.

  13. Molecular simulations of CO2 at interfaces

    DEFF Research Database (Denmark)

    Silvestri, Alessandro

    . DFT has some advantages over MD in terms of computational cost but MD allows exploration of larger and more complex systems. Dierent options for geologic storage of CO2 have been proposed. Carbonate minerals are ubiquitous, limestone, chalk and marble constitute a signicant fraction of the sedimentary...... rock record and the formations are generally porous so their probable response to CO2 sequestration needs to be investigated. However, despite the large number of geologic sequestration publications on water{rock interactions over the last decade, studies on carbonate reservoirs remain scarce....... Carbonate reservoirs are being considered as CO2 storage sites so more information is needed, for providing data for safety assessment models and for fundamental understanding of the relevant processes and their in uence. Theoretical approaches for the carbonate minerals are even more scarce and only few...

  14. CO2 fluxes near a forest edge

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Leclerc, Monique Y.; Zhang, Gensheng

    2008-01-01

    the concentration and flux fields against those of a uniform forested surface. We use an atmospheric boundary layer two-equation closure model that accounts for the flow dynamics and vertical divergence of CO2 sources/sinks within a plant canopy. This paper characterizes the spatial variation of CO2 fluxes...... as a function of both sources/sinks distribution and the vertical structure of the canopy. Results suggest that the ground source plays a major role in the formation of wave-like vertical CO2 flux behavior downwind of a forest edge, despite the fact that the contribution of foliage sources/sinks changes...... monotonously. Such a variation is caused by scalar advection in the trunk space and reveals itself as a decrease or increase in vertical fluxes over the forest relative to carbon dioxide exchange of the underlying forest. The effect was more pronounced in model forests where the leaf area is concentrated...

  15. A cost effective CO2 strategy

    DEFF Research Database (Denmark)

    are evaluated according to CO2 reduction potential and according to the ‘shadow price’ on a reduction of one ton CO2. The shadow price reflects the costs (and benefits) of the different measures. Comparing the measures it is possible to identify cost effective measures, but these measures are not necessarily......) between measures are also addressed. It has not been possible to analyse combinations and packages of measures consistently in a model like the on outlined above. However, the obvious connections are addressed and clearly show the limitations with respect to fulfilling the target set by the Kyoto protocol...... national strategies for climate and transport and associated implementation deficits will be discussed, reflecting the presently changing institutional conditions for policy formulation and implementation. The main differences compared to earlier CO2 strategies are the EU ETS and targets set for non...

  16. The ATLAS IBL CO2 Cooling System

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00237783; The ATLAS collaboration; Zwalinski, L.; Bortolin, C.; Vogt, S.; Godlewski, J.; Crespo-Lopez, O.; Van Overbeek, M.; Blaszcyk, T.

    2017-01-01

    The ATLAS Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity.

  17. Decoupling of CO2 emissions and GDP

    Directory of Open Access Journals (Sweden)

    Yves Rocha de Salles Lima

    2016-12-01

    Full Text Available The objetive of this work is to analyze the variation of CO2 emissions and GDP per capita throughout the years and identify the possible interaction between them. For this purpose, data from the International Energy Agency was collected on two countries, Brazil and the one with the highest GDP worldwide, the United States. Thus, the results showed that CO2 emissions have been following the country’s economic growth for many years. However, these two indicators have started to decouple in the US in 2007 while in Brazil the same happened in 2011. Furthermore, projections for CO2 emissions are made until 2040, considering 6 probable scenarios. These projections showed that even if the oil price decreases, the emissions will not be significantly affected as long as the economic growth does not decelerate.

  18. Local CO2-induced swelling of shales

    Science.gov (United States)

    Pluymakers, Anne; Dysthe, Dag Kristian

    2017-04-01

    In heterogeneous shale rocks, CO2 adsorbs more strongly to organic matter than to the other components. CO2-induced swelling of organic matter has been shown in coal, which is pure carbon. The heterogeneity of the shale matrix makes an interesting case study. Can local swelling through adsorption of CO2 to organic matter induce strain in the surrounding shale matrix? Can fractures close due to CO2-induced swelling of clays and organic matter? We have developed a new generation of microfluidic high pressure cells (up to 100 bar), which can be used to study flow and adsorption phenomena at the microscale in natural geo-materials. The devices contain one transparent side and a shale sample on the other side. The shale used is the Pomeranian shale, extracted from 4 km depth in Poland. This formation is a potential target of a combined CO2-storage and gas extraction project. To answer the first question, we place the pressure cell under a Veeco NT1100 Interferometer, operated in Vertical Scanning Interferometry mode and equipped with a Through Transmissive Media objective. This allows for observation of local swelling or organic matter with nanometer vertical resolution and micrometer lateral resolution. We expose the sample to CO2 atmospheres at different pressures. Comparison of the interferometry data and using SEM-EDS maps plus optical microscopy delivers local swelling maps where we can distinguish swelling of different mineralogies. Preliminary results indicate minor local swelling of organic matter, where the total amount is both time- and pressure-dependent.

  19. 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

  20. Kronikken: Handel og handling med CO2

    DEFF Research Database (Denmark)

    Andersen, M. S.

    2000-01-01

    De fleksible mekanismer i Kyoto-aftalen fortjener indgående overvejelser, ikke kun fordi de giver mulighed for en rabat på CO2-reduktionen, men også fordi de rummer globale og sikkerhedspolitiske dimensioner som er essentielle.......De fleksible mekanismer i Kyoto-aftalen fortjener indgående overvejelser, ikke kun fordi de giver mulighed for en rabat på CO2-reduktionen, men også fordi de rummer globale og sikkerhedspolitiske dimensioner som er essentielle....

  1. Modelling the Martian CO2 Ice Clouds

    Science.gov (United States)

    Listowski, Constantino; Määttänen, A.; Montmessin, F.; Lefèvre, F.

    2012-10-01

    Martian CO2 ice cloud formation represents a rare phenomenon in the Solar System: the condensation of the main component of the atmosphere. Moreover, on Mars, condensation occurs in a rarefied atmosphere (large Knudsen numbers, Kn) that limits the growth efficiency. These clouds form in the polar winter troposphere and in the mesosphere near the equator. CO2 ice cloud modeling has turned out to be challenging: recent efforts (e.g. [1]) fail in explaining typical small sizes (80 nm-130 nm) observed for mesospheric clouds [2]. Supercold pockets (TWood, S. E., (1999), Ph.D. thesis, UCLA [6] Young, J. B., J. Geophys. Res., 36, 294-2956, 1993

  2. Capture and Geological Storage of CO2

    International Nuclear Information System (INIS)

    Kerr, T.; Brockett, S.; Hegan, L.; Barbucci, P.; Tullius, K.; Scott, J.; Otter, N.; Cook, P.; Hill, G.; Dino, R.; Aimard, N.; Giese, R.; Christensen, N.P.; Munier, G.; Paelinck, Ph.; Rayna, L.; Stromberg, L.; Birat, J.P.; Audigane, P.; Loizzo, M.; Arts, R.; Fabriol, H.; Radgen, P.; Hartwell, J.; Wartmann, S.; Drosin, E.; Willnow, K.; Moisan, F.

    2009-01-01

    To build on the growing success of the first two international symposia on emission reduction and CO 2 capture and geological storage, held in Paris in 2005 and again in 2007, IFP, ADEME and BRGM organised a third event on the same topic the 5-6 November 2009. This time, the focus was on the urgency of industrial deployment. Indeed, the IPCC 4. assessment report indicates that the world must achieve a 50 to 85% reduction in CO 2 emissions by 2050 compared to 2000, in order to limit the global temperature increase to around 2 deg. C. Moreover, IPCC stresses that a 'business as usual' scenario could lead to a temperature increase of between 4 deg. C to 7 deg. C across the planet. The symposium was organized in 4 sessions: Session I - Regulatory framework and strategies for enabling CCS deployment: - CCS: international status of political, regulatory and financing issues (Tom Kerr, IEA); - EC regulatory framework (Scott Brockett, European Commission, DG ENV); - Canada's investments towards implementation of CCS in Canada (Larry Hegan, Office of Energy Research and Development - Government of Canada); - A power company perspective (Pietro Barbucci, ENEL); - EC CCS demonstration network (Kai Tullius, European Commission, DG TREN); - Strategies and policies for accelerating global CCS deployment (Jesse Scott, E3G); - The global CCS Institute, a major initiative to facilitate the rapid deployment of CCS (Nick Otter, GCCSI); Session II - From pilot to demonstration projects: - Otway project, Australia (David Hilditch, CO2 CRC); - US regional partnerships (Gerald Hill, Southeast Regional Carbon Sequestration Partnership - SECARB); - CCS activities in Brazil (Rodolfo Dino, Petrobras); - Lessons learnt from Ketzin CO2Sink project in Germany (Ruediger Giese, GFZ); - CO 2 storage - from laboratory to reality (Niels-Peter Christensen, Vattenfall); - Valuation and storage of CO 2 : A global project for carbon management in South-East France (Gilles Munier, Geogreen); Session III

  3. CO2 convective dissolution controlled by temporal changes in free-phase CO2 properties

    Science.gov (United States)

    Jafari Raad, S. M.; Emami-Meybodi, H.; Hassanzadeh, H.

    2017-12-01

    Understanding the factors that control CO2 convective dissolution, which is one of the permanent trapping mechanisms, in the deep saline aquifer is crucial in the long-term fate of the injected CO2. The present study investigates the effects of temporal changes in the solubility of CO2 at the free-phase CO2/brine interface on the onset of natural convection and the subsequent convective mixing by conducting linear stability analyses (LSA) and direct numerical simulations (DNS). A time-dependent concentration boundary is considered for the free-phase CO2/brine interface where the CO2 concentration first decreases with the time and then remains constant. The LSA results show that the temporal variation in the concentration increases the onset of natural convection up to two orders of magnitude. In addition, the critical Rayleigh number significantly increases as CO2 concentration decreases. In other words, size and pressure of the injected CO2 affect the commencement of convective mixing. Based on LSA results, several scaling relations are proposed to correlate critical Rayleigh number, critical time, and its corresponding wavenumbers with time-dependent boundary's parameters, such as concentration decline rate and equilibrium concentration ratio. The DNS results reveal that the convective fingering patterns are significantly influenced by the variation of CO2 concentration at the interface. These findings improve our understanding of CO2 solubility trapping and are particularly important in estimation of potential storage capacity, risk assessment, and storage sites characterization and screening. Keywords: CO2 sequestration; natural convection; solubility trapping; time-dependent boundary condition; numerical simulation; stability analysis

  4. CO2 emissions of nuclear electricity generation

    International Nuclear Information System (INIS)

    Wissel, Steffen; Mayer-Spohn, Oliver; Fahl, Ulrich; Blesl, Markus; Voss, Alfred

    2008-01-01

    A survey of LCA studies on nuclear electricity generation revealed life cycle CO 2 emissions ranging between 3 g/kWhe to 60 g/kWhe and above. Firstly, this paper points out the discrepancies in studies by estimating the CO 2 emissions of nuclear power generation. Secondly, the paper sets out to provide critical review of future developments of the fuel cycle for light water reactors and illustrates the impact of uncertainties on the specific CO 2 emissions of nuclear electricity generation. Each step in the fuel cycle will be considered and with regard to the CO 2 emissions analysed. Thereby different assumptions and uncertainty levels are determined for the nuclear fuel cycle. With the impacts of low uranium ore grades for mining and milling as well as higher burn-up rates future fuel characteristics are considered. Sensitivity analyses are performed for all fuel processing steps, for different technical specifications of light water reactors as well as for further external frame conditions. (authors)

  5. Plasma Arc Augmented CO2 laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Andersen, Mikkel; Frederiksen, Niels

    2001-01-01

    In order to reduce the hardness of laser beam welded 2.13 mm medium strength steel CMn 250, a plasma arc has been used simultaneously with a 2.6 kW CO2 laser source. In a number of systematic laboratory tests, the plasma arc current, plasma gas flow and distance to the laser source were varied...

  6. Chilled ammonia process for CO2 capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; van Well, Willy J. M

    2009-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2-10 degrees C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows...

  7. Chilled Ammonia Process for CO2 Capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

    2010-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...

  8. Artificial photosynthesis - CO2 towards methanol

    Science.gov (United States)

    Nazimek, D.; Czech, B.

    2011-03-01

    The new insight into the problem of carbon dioxide utilization into valuable compound - methanol and then its transformation into fuel is presented. Because the highly endothermic requirements of the reaction of CO2 hydrogenation a photocatalytic route is applied. Combining of the two reactions: water splitting and CO2 hydrogenation using H2O as a source of hydrogen at the same time and place are proposed. The studies over modified TiO2 catalysts supported on Al2O3 were conducted in a self-designed circulated photocatalytic reaction system under at room temperature and constant pressure. Experimental results indicated that the highest yield of the photoreduction of CO2 with H2O were obtained using TiO2 with the active anatase phase modified by Ru and WO3 addition. The conversion was very high - almost 97% of CO2 was transformed mainly into methanol (14%vol.) and into small amount of formic and acetic acid and ester.

  9. Harvesting Energy from CO2 Emissions

    NARCIS (Netherlands)

    Hamelers, H.V.M.; Schaetzle, O.; Paz-García, J.M.; Biesheuvel, P.M.; Buisman, C.J.N.

    2014-01-01

    When two fluids with different compositions are mixed, mixing energy is released. This holds true for both liquids and gases, though in the case of gases, no technology is yet available to harvest this energy source. Mixing the CO2 in combustion gases with air represents a source of energy with a

  10. Carbon dioxide (CO2) utilizing strain database

    African Journals Online (AJOL)

    Jane

    2011-10-17

    Oct 17, 2011 ... CSD can be used to gain information related to CO2 fixing microbes. It can also contribute to devising biological strategies for reducing carbon dioxide from the environment. It introduces an innovative idea of exploring the potential of these bacterial strains for reversing global warming. The CSD can be.

  11. Climate change and CO2 emission reductions

    International Nuclear Information System (INIS)

    Ha Duong, M.; Campos, A.S.

    2007-04-01

    This paper presents the results of an opinion poll performed on a representative sample of 1000 persons about their sensitivity to climate change and to environment protection, their knowledge about technologies which are useful for environment protection, their opinion about geological CO 2 sequestration, and technologies to be developed to struggle against climate warming

  12. CO2 laser used in cosmetology

    Science.gov (United States)

    Su, Chenglie

    1993-03-01

    Cases of various kinds of warts, nevi, papillomas, skin angiomas, ephilises, skin vegetation, scars and brandy noses were vaporized and solidified with a 2.5 - 8 W low power CO2 laser with an overall satisfaction rate up to 99.8% and the satisfaction rate for one time 92%.

  13. CO2 laser in stapes surgery

    Science.gov (United States)

    Jovanovic, Sergije; Schoenfeld, Uwe; Berghaus, Andreas; Fischer, R.; Scherer, Hans H.

    1993-07-01

    Stapedotomy is not only one of the most successful interventions in otology but also one of the most dangerous for the inner ear. To reduce the risk of damaging middle and inner ear structures through manipulations with conventional instruments, the CO2 laser beam is used for perforating the footplate and removing the suprastructures. This non-contact technique aims at precise and controlled management of middle ear structures. Consideration is given to the impact of experimental data on the clinical application of the CO2 laser in stapes surgery. The discussion covers the advantages and disadvantages with regard to optical and tissue-related properties and points out possible dangers to the inner ear. Our experimental and clinical experience is taken as a basis for examining the surgical technique and the varying demands made on the laser beam in treating the stapedial tendon, crura and footplate. Attention is called to the need for additional instruments. Effective energy parameters for CO2 laser stapedeotomy are evaluated for different lasers. Application of the CO2 laser contributes towards optimization of this high-precision intervention and promises to reduce the incidence of inner ear damages in large numbers of cases. This technique appears useful particularly in difficult anatomic situations and, above all, for revisional operations.

  14. Managing CO2 emissions in Nigeria

    International Nuclear Information System (INIS)

    Obioh, I.B.; Oluwole, A.F.; Akeredolu, F.A.

    1994-01-01

    The energy resources in Nigeria are nearly equally divided between fossil fuels and biofuels. The increasing pressure on them, following expected increased population growth, may lead to substantial emissions of carbon into the atmosphere. Additionally agricultural and forestry management practices in vogue are those related to savannah burning and rotational bush fallow systems, which have been clearly implicated as important sources of CO 2 and trace gases. An integrated model for the prediction of future CO 2 emissions based on fossil fuels and biomass fuels requirements, rates of deforestation and other land-use indices is presented. This is further based on trends in population and economic growth up to the year 2025, with a base year in 1988. A coupled carbon cycle-climate model based on the contribution of CO 2 and other trace gases is established from the proportions of integrated global warming effects for a 20-year averaging time using the product of global warming potential (GWP) and total emissions. An energy-technology inventory approach to optimal resources management is used as a tool for establishing the future scope of reducing the CO 2 emissions through improved fossil fuel energy efficiencies. Scenarios for reduction based on gradual to swift shifts from biomass to fossil and renewable fuels are presented together with expected policy options required to effect them

  15. Detection of 14CO2 in radiotoxicology

    International Nuclear Information System (INIS)

    Simonnet, Francoise; Bocquet, Colette.

    1980-12-01

    14 CO 2 is detected in exhaled air by conversion to Ba 14 CO 3 which is then filtered, dried and weighed. The radioactivity is measured by liquid scintillation counting. The radioactivity is expressed in μCi per litre of exhaled air according to the ICRP recommendations. The detection threshold is well below the values indicated by the ICRP [fr

  16. Stereotactic CO2 laser therapy for hydrocephalus

    Science.gov (United States)

    Kozodoy-Pins, Rebecca L.; Harrington, James A.; Zazanis, George A.; Nosko, Michael G.; Lehman, Richard M.

    1994-05-01

    A new fiber-optic delivery system for CO2 radiation has been used to successfully treat non-communicating hydrocephalus. This system consists of a hollow sapphire waveguide employed in the lumen of a stereotactically-guided neuroendoscope. CO2 gas flows through the bore of the hollow waveguide, creating a path for the laser beam through the cerebrospinal fluid (CSF). This delivery system has the advantages of both visualization and guided CO2 laser radiation without the same 4.3 mm diameter scope. Several patients with hydrocephalus were treated with this new system. The laser was used to create a passage in the floor of the ventricle to allow the flow of CSF from the ventricles to the sub-arachnoid space. Initial postoperative results demonstrated a relief of the clinical symptoms. Long-term results will indicate if this type of therapy will be superior to the use of implanted silicone shunts. Since CO2 laser radiation at 10.6 micrometers is strongly absorbed by the water in tissue and CSF, damage to tissue surrounding the lesion with each laser pulse is limited. The accuracy and safety of this technique may prove it to be an advantageous therapy for obstructive hydrocephalus.

  17. Heterotrophic fixation of CO2 in soil

    Czech Academy of Sciences Publication Activity Database

    Šantrůčková, Hana; Bird, M. I.; Elhottová, Dana; Novák, Jaroslav; Picek, T.; Šimek, Miloslav; Tykva, Richard

    2005-01-01

    Roč. 49, č. 2 (2005), s. 218-225 ISSN 0095-3628 R&D Projects: GA ČR(CZ) GA206/02/1036; GA AV ČR(CZ) IAA6066901 Institutional research plan: CEZ:AV0Z60660521 Keywords : heterotrophic fixation * CO2 * soil Subject RIV: EH - Ecology, Behaviour Impact factor: 2.674, year: 2005

  18. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    , the capacity of synthetic raw meal was similar to that of pure limestone, whereas at 950 °C in N2 and in a CO2-rich atmosphere there was a significant difference. The SEM and BET analyses indicate that sintering is the main reason for the lower capture capacity of the limestone in the raw meal. The main...

  19. Exercise carbon dioxide (CO2) retention with inhaled CO2 and breathing resistance.

    Science.gov (United States)

    Shykoff, Barbara E; Warkander, Dan E

    2012-01-01

    Combined effects on respiratory minute ventilation (VE)--and thus, on end-tidal carbon dioxide partial pressure (P(ET)CO2)--of breathing resistance and elevated inspired carbon dioxide (CO2) had not been determined during heavy exercise. In this Institutional Review Board-approved, dry, sea-level study, 12 subjects in each of three phases exercised to exhaustion at 85% peak oxygen uptake while V(E) and P(ET)CO2 were measured. Participants inhaled 0%, 1%, 2% or 3% CO2 in air, or 0% or 2% CO2 in oxygen, with or without breathing resistance, mimicking the U.S. Navy's MK 16 rebreather underwater breathing apparatus (UBA). Compared to air baseline (0% inspired CO2 in air without resistance): (1) Oxygen decreased baseline V(E) (p carbon dioxide partial pressure and respiratory effort. Because elevated CO2 may not increase V(E) if breathing resistance and VE are high, rebreather UBA safety requires very low inspired CO2.

  20. Sustained effects of atmospheric [CO2] and nitrogen availability on forest soil CO2 efflux

    Science.gov (United States)

    A. Christopher Oishi; Sari Palmroth; Kurt H. Johnsen; Heather R. McCarthy; Ram. Oren

    2014-01-01

    Soil CO2 efflux (Fsoil) is the largest source of carbon from forests and reflects primary productivity as well as how carbon is allocated within forest ecosystems. Through early stages of stand development, both elevated [CO2] and availability of soil nitrogen (N; sum of mineralization, deposition, and fixation) have been shown to increase gross primary productivity,...

  1. Uncertainties in the CO2 buget associated to boundary layer dynamics and CO2-advection

    NARCIS (Netherlands)

    Kaikkonen, J.P.; Pino, D.; Vilà-Guerau de Arellano, J.

    2012-01-01

    The relationship between boundary layer dynamics and carbon dioxide (CO2) budget in the convective boundary layer (CBL) is investigated by using mixed-layer theory. We derive a new set of analytical relations to quantify the uncertainties on the estimation of the bulk CO2 mixing ratio and the

  2. Literatuuronderzoek CAM-fotosynthese en CO2-bemesting en CO2-bemesting bij bromelia's

    NARCIS (Netherlands)

    Marissen, A.; Warmenhoven, M.G.

    2004-01-01

    De ‘normale’ wijze van CO2-opname gebeurt bij de meeste planten overdag, wanneer er licht is om de opgenomen CO2 door middel van fotosynthese direct om te zetten in suikers. Hiervoor is het nodig dat de huidmondjes overdag open staan, ‘s nachts zijn huidmondjes meestal dicht. Via de huidmondjes gaat

  3. CO2 emissions vs. CO2 responsibility: An input-output approach for the Turkish economy

    International Nuclear Information System (INIS)

    Ipek Tunc, G.; Tueruet-Asik, Serap; Akbostanci, Elif

    2007-01-01

    Recently, global warming (greenhouse effect) and its effects have become one of the hottest topics in the world agenda. There have been several international attempts to reduce the negative effects of global warming. The Kyoto Protocol can be cited as the most important agreement which tries to limit the countries' emissions within a time horizon. For this reason, it becomes important to calculate the greenhouse gas emissions of countries. The aim of this study is to estimate the amount of CO 2 -the most important greenhouse gas-emissions, for the Turkish economy. An extended input-output model is estimated by using 1996 data in order to identify the sources of CO 2 emissions and to discuss the share of sectors in total emission. Besides, 'CO 2 responsibility', which takes into account the CO 2 content of imports, is estimated for the Turkish economy. The sectoral CO 2 emissions and CO 2 responsibilities are compared and these two notions are linked to foreign trade volume. One of the main conclusions is that the manufacturing industry has the first place in both of the rankings for CO 2 emissions and CO 2 responsibilities, while agriculture and husbandry has the last place

  4. Development of Novel CO2 Adsorbents for Capture of CO2 from Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Fauth, D.J.; Filburn, T.P. (University of Hartford, West Hartford, CT); Gray, M.L.; Hedges, S.W.; Hoffman, J.; Pennline, H.W.; Filburn, T.

    2007-06-01

    Capturing CO2 emissions generated from fossil fuel-based power plants has received widespread attention and is considered a vital course of action for CO2 emission abatement. Efforts are underway at the Department of Energy’s National Energy Technology Laboratory to develop viable energy technologies enabling the CO2 capture from large stationary point sources. Solid, immobilized amine sorbents (IAS) formulated by impregnation of liquid amines within porous substrates are reactive towards CO2 and offer an alternative means for cyclic capture of CO2 eliminating, to some degree, inadequacies related to chemical absorption by aqueous alkanolamine solutions. This paper describes synthesis, characterization, and CO2 adsorption properties for IAS materials previously tested to bind and release CO2 and water vapor in a closed loop life support system. Tetraethylenepentamine (TEPA), acrylonitrile-modified tetraethylenepentamine (TEPAN), and a single formulation consisting of TEPAN and N, N’-bis(2-hydroxyethyl)ethylenediamine (BED) were individually supported on a poly (methyl methacrylate) (PMMA) substrate and examined. CO2 adsorption profiles leading to reversible CO2 adsorption capacities were obtained using thermogravimetry. Under 10% CO2 in nitrogen at 25°C and 1 atm, TEPA supported on PMMA over 60 minutes adsorbed ~3.2 mmol/g{sorbent} whereas, TEPAN supported on PMMA along with TEPAN and BED supported on PMMA adsorbed ~1.7 mmol/g{sorbent} and ~2.3 mmol/g{sorbent} respectively. Cyclic experiments with a 1:1 weight ratio of TEPAN and BED supported on poly (methyl methacrylate) beads utilizing a fixed-bed flow system with 9% CO2, 3.5% O2, nitrogen balance with trace gas constituents were studied. CO2 adsorption capacity was ~ 3 mmols CO2/g{sorbent} at 40°C and 1.4 atm. No beneficial effect on IAS performance was found using a moisture-laden flue gas mixture. Tests with 750 ppmv NO in a humidified gas stream revealed negligible NO sorption onto the IAS. A high SO2

  5. Extraction of lipids from microalgae using CO2-expanded methanol and liquid CO2.

    Science.gov (United States)

    Paudel, Ashok; Jessop, Michael J; Stubbins, Spencer H; Champagne, Pascale; Jessop, Philip G

    2015-05-01

    The use of CO2-expanded methanol (cxMeOH) and liquid carbon dioxide (lCO2) is proposed to extract lipids from Botryococcus braunii. When compressed CO2 dissolves in methanol, the solvent expands in volume, decreases in polarity and so increases in its selectivity for biodiesel desirable lipids. Solid phase extraction of the algal extract showed that the cxMeOH extracted 21 mg of biodiesel desirable lipids per mL of organic solvent compared to 3mg/mL using either neat methanol or chloroform/methanol mixture. The non-polar lCO2 showed a high affinity for non-polar lipids. Using lCO2, it is possible to extract up to 10% neutral lipids relative to the mass of dry algae. Unlike extractions using conventional solvents, these new methods require little to no volatile, flammable, or chlorinated organic solvents. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Flash scanning the CO2 laser: a revival of the CO2 laser in plastic surgery

    Science.gov (United States)

    Lach, Elliot

    1994-09-01

    The CO2 laser has broad clinical application yet also presents a number of practical disadvantages. These drawbacks have limited the success and utilization of this laser in plastic surgery. Flashscanner technology has recently been used for char-free CO2 laser surgery of the oropharynx, the external female genital tract, and perirectal mucosa. A commercially available optomechanical flashscanner unit `Swiftlase,' was adapted to a CO2 laser and used for treatment in numerous plastic surgical applications. Conditions and situations that were treated in this study included generalized neurofibromatosis, tuberous sclerosis, rhinophyma, viral warts, breast reconstruction, and deepithelialization prior to microsurgery or local flap transfer and/or skin graft placement. There were no significant wound healing complications. Some patients previously sustained undue scarring from conventional CO2 laser surgery. Conservative, primarily ablative CO2 laser surgery with the Swiftlase has usefulness for treatment of patients in plastic surgery including those that were previously unsuccessfully treated.

  7. The Li–CO2 battery: a novel method for CO2 capture and utilization

    KAUST Repository

    Xu, Shaomao

    2013-01-01

    We report a novel primary Li-CO2 battery that consumes pure CO2 gas as its cathode. The battery exhibits a high discharge capacity of around 2500 mA h g-1 at moderate temperatures. At 100 °C the discharge capacity is close to 1000% higher than that at 40 °C, and the temperature dependence is significantly weaker for higher surface area carbon cathodes. Ex-situ FTIR and XRD analyses convincingly show that lithium carbonate (Li2CO3) is the main component of the discharge product. The feasibility of similar primary metal-CO2 batteries based on earth abundant metal anodes, such as Al and Mg, is demonstrated. The metal-CO2 battery platform provides a novel approach for simultaneous capturing of CO2 emissions and producing electrical energy. © 2013 The Royal Society of Chemistry.

  8. Imaging volcanic CO2 and SO2

    Science.gov (United States)

    Gabrieli, A.; Wright, R.; Lucey, P. G.; Porter, J. N.

    2017-12-01

    Detecting and quantifying volcanic carbon dioxide (CO2) and sulfur dioxide (SO2) emissions is of relevance to volcanologists. Changes in the amount and composition of gases that volcanoes emit are related to subsurface magma movements and the probability of eruptions. Volcanic gases and related acidic aerosols are also an important atmospheric pollution source that create environmental health hazards for people, animals, plants, and infrastructures. For these reasons, it is important to measure emissions from volcanic plumes during both day and night. We present image measurements of the volcanic plume at Kīlauea volcano, HI, and flux derivation, using a newly developed 8-14 um hyperspectral imaging spectrometer, the Thermal Hyperspectral Imager (THI). THI is capable of acquiring images of the scene it views from which spectra can be derived from each pixel. Each spectrum contains 50 wavelength samples between 8 and 14 um where CO2 and SO2 volcanic gases have diagnostic absorption/emission features respectively at 8.6 and 14 um. Plume radiance measurements were carried out both during the day and the night by using both the lava lake in the Halema'uma'u crater as a hot source and the sky as a cold background to detect respectively the spectral signatures of volcanic CO2 and SO2 gases. CO2 and SO2 path-concentrations were then obtained from the spectral radiance measurements using a new Partial Least Squares Regression (PLSR)-based inversion algorithm, which was developed as part of this project. Volcanic emission fluxes were determined by combining the path measurements with wind observations, derived directly from the images. Several hours long time-series of volcanic emission fluxes will be presented and the SO2 conversion rates into aerosols will be discussed. The new imaging and inversion technique, discussed here, are novel allowing for continuous CO2 and SO2 plume mapping during both day and night.

  9. CO2 Orbital Trends in Comets

    Science.gov (United States)

    Kelley, Michael; Feaga, Lori; Bodewits, Dennis; McKay, Adam; Snodgrass, Colin; Wooden, Diane

    2014-12-01

    Spacecraft missions to comets return a treasure trove of details of their targets, e.g., the Rosetta mission to comet 67P/Churyumov-Gerasimenko, the Deep Impact experiment at comet 9P/Tempel 1, or even the flyby of C/2013 A1 (Siding Spring) at Mars. Yet, missions are rare, the diversity of comets is large, few comets are easily accessible, and comet flybys essentially return snapshots of their target nuclei. Thus, telescopic observations are necessary to place the mission data within the context of each comet's long-term behavior, and to further connect mission results to the comet population as a whole. We propose a large Cycle 11 project to study the long-term activity of past and potential future mission targets, and select bright Oort cloud comets to infer comet nucleus properties, which would otherwise require flyby missions. In the classical comet model, cometary mass loss is driven by the sublimation of water ice. However, recent discoveries suggest that the more volatile CO and CO2 ices are the likely drivers of some comet active regions. Surprisingly, CO2 drove most of the activity of comet Hartley 2 at only 1 AU from the Sun where vigorous water ice sublimation would be expected to dominate. Currently, little is known about the role of CO2 in comet activity because telluric absorptions prohibit monitoring from the ground. In our Cycle 11 project, we will study the CO2 activity of our targets through IRAC photometry. In conjunction with prior observations of CO2 and CO, as well as future data sets (JWST) and ongoing Earth-based projects led by members of our team, we will investigate both long-term activity trends in our target comets, with a particular goal to ascertain the connections between each comet's coma and nucleus.

  10. The Role of the CO2 Laser and Fractional CO2 Laser in Dermatology.

    Science.gov (United States)

    Omi, Tokuya; Numano, Kayoko

    2014-03-27

    Tremendous advances have been made in the medical application of the laser in the past few decades. Many diseases in the dermatological field are now indications for laser treatment that qualify for reimbursement by many national health insurance systems. Among laser types, the carbon dioxide (CO2) laser remains an important system for the dermatologist. The lasers used in photosurgery have wavelengths that differ according to their intended use and are of various types, but the CO2 laser is one of the most widely used lasers in the dermatology field. With its wavelength in the mid-infrared at 10,600 nm, CO2 laser energy is wellabsorbed in water. As skin contains a very high water percentage, this makes the CO2 laser ideal for precise, safe ablation with good hemostasis. In addition to its efficacy in ablating benign raised lesions, the CO2 laser has been reported to be effective in the field of esthetic dermatology in the revision of acne scars as well as in photorejuvenation. With the addition of fractionation of the beam of energy into myriad microbeams, the fractional CO2 laser has offered a bridge between the frankly full ablative indications and the nonablative skin rejuvenation systems of the 2000s in the rejuvenation of photoaged skin on and off the face. The CO2 laser remains an efficient, precise and safe system for the dermatologist. Technological advances in CO2 laser construction have meant smaller spot sizes and greater precision for laser surgery, and more flexibility in tip sizes and protocols for fractional CO2 laser treatment. The range of dermatological applications of the CO2 laser is expected to continue to increase in the future.

  11. Nickel Nanoparticles Production using Pulsed Laser Ablation under Pressurized CO2

    Science.gov (United States)

    Mardis, Mardiansyah; Takada, Noriharu; Machmudah, Siti; Diono, Wahyu; Kanda, Hideki; Sasaki, Koichi; Goto, Motonobu

    2014-10-01

    We used nickel (Ni) plate as a target and irradiated pulse laser ablation with a fundamental wavelength of 1064 nm under pressurized CO2. The Ni plate was ablated at various pressure (5-15 MPa), temperature (15-80°), and irradiation time (3-30 min). The method successfully generated Ni nanoparticles in various shape and size. Generated Ni nanoparticles collected on a Si wafer and the ablated Ni plate were analyzed by Field Emission Scanning Electron Microscope (FE-SEM). With changing pressure and temperature, the structures of Ni nanoparticles also changed. The shape of generated particles is sphere-like structure with diameter around 10--100 nm. Also it was observed that a network structure of smaller particles was fabricated. The mechanism of nanoparticles fabrication could be explained as follows. Ablated nickel plate melted during the ablation process and larger particles formed, then ejected smaller spherical nanoparticles, which formed nanoclusters attached on the large particles. This morphology of particles was also observed for gold and silver nanoparticles with same condition. Further, the optical emission intensity from ablation plasma and the volume of the ablated crater were also examined under pressurized CO2.

  12. CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project

    Directory of Open Access Journals (Sweden)

    C. Lac

    2013-05-01

    Full Text Available Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is a challenging and interesting task needed to be performed in order to utilise CO2 measurements in an atmospheric inverse framework and to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town Energy Balance (TEB urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs surface scheme, allowing a full interaction of CO2 modelling between the surface and the atmosphere. Statistical scores show a good representation of the urban heat island (UHI with stronger urban–rural contrasts on temperature at night than during the day by up to 7 °C. Boundary layer heights (BLH have been evaluated on urban, suburban and rural sites during the campaign, and also on a suburban site over 1 yr. The diurnal cycles of the BLH are well captured, especially the onset time of the BLH increase and its growth rate in the morning, which are essential for tall tower CO2 observatories. The main discrepancy is a small negative bias over urban and suburban sites during nighttime (respectively 45 m and 5 m, leading to a few overestimations of nocturnal CO2 mixing ratios at suburban sites and a bias of +5 ppm. The diurnal CO2 cycle is generally well captured for all the sites. At the Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the atmospheric boundary layer (ABL growth reaches the measurement height. At suburban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a strong spatio-temporal variability. A

  13. Strengthening seasonal marine CO2 variations due to increasing atmospheric CO2

    Science.gov (United States)

    Landschützer, Peter; Gruber, Nicolas; Bakker, Dorothee C. E.; Stemmler, Irene; Six, Katharina D.

    2018-02-01

    The increase of atmospheric CO2 (ref. 1) has been predicted to impact the seasonal cycle of inorganic carbon in the global ocean2,3, yet the observational evidence to verify this prediction has been missing. Here, using an observation-based product of the oceanic partial pressure of CO2 (pCO2) covering the past 34 years, we find that the winter-to-summer difference of the pCO2 has increased on average by 2.2 ± 0.4 μatm per decade from 1982 to 2015 poleward of 10° latitude. This is largely in agreement with the trend expected from thermodynamic considerations. Most of the increase stems from the seasonality of the drivers acting on an increasing oceanic pCO2 caused by the uptake of anthropogenic CO2 from the atmosphere. In the high latitudes, the concurrent ocean-acidification-induced changes in the buffer capacity of the ocean enhance this effect. This strengthening of the seasonal winter-to-summer difference pushes the global ocean towards critical thresholds earlier, inducing stress to ocean ecosystems and fisheries4. Our study provides observational evidence for this strengthening seasonal difference in the oceanic carbon cycle on a global scale, illustrating the inevitable consequences of anthropogenic CO2 emissions.

  14. Flexible metal-organic framework compounds: In situ studies for selective CO2 capture

    International Nuclear Information System (INIS)

    Allen, A.J.; Espinal, L.; Wong-Ng, W.; Queen, W.L.; Brown, C.M.; Kline, S.R.; Kauffman, K.L.; Culp, J.T.; Matranga, C.

    2015-01-01

    Results are presented that explore the dynamic structural changes occurring in two highly flexible nanocrystalline metal-organic framework (MOF) compounds during the adsorption and desorption of pure gases and binary mixtures. The Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN) 4 ] and catena-bis(dibenzoylmethanato)-(4,4′-bipyridyl)nickel(II) chosen for this study are 3-D and 1-D porous coordination polymers (PCP) with a similar gate opening pressure response for CO 2 isotherms at 303 K, but with differing degrees of flexibility for structural change to accommodate guest molecules. As such, they serve as a potential model system for evaluating the complex kinetics associated with dynamic structure changes occurring in response to gas adsorption in flexible MOF systems. Insights into the crystallographic changes occurring as the MOF pore structure expands and contracts in response to interactions with CO 2 , N 2 , and CO 2 /N 2 mixtures have been obtained from in situ small-angle neutron scattering and neutron diffraction, combined with ex situ X-ray diffraction structure measurements. The role of structure in carbon capture functionality is discussed with reference to the ongoing characterization challenges and a possible materials-by-design approach. - Graphical abstract: We present in situ small-angle neutron scattering results for two flexible metal-organic frameworks (MOFs). The figure shows that for one (NiBpene, high CO 2 adsorption) the intensity of the Bragg peak for the expandable d-spacing most associated with CO 2 adsorption varies approximately with the isotherm, while for the other (NiDBM-Bpy, high CO 2 selectivity) the d-spacing, itself, varies with the isotherm. The cartoons show the proposed modes of structural change. - Highlights: • Dynamic structures of two flexible MOF CO 2 sorbent compounds are compared in situ. • These porous solid sorbents serve as models for pure & dual gas adsorption. • Different degrees of structural freedom give different

  15. CO2 Capture by Injection of Flue Gas or CO2-N2 Mixtures into Hydrate Reservoirs: Dependence of CO2 Capture Efficiency on Gas Hydrate Reservoir Conditions.

    Science.gov (United States)

    Hassanpouryouzband, Aliakbar; Yang, Jinhai; Tohidi, Bahman; Chuvilin, Evgeny; Istomin, Vladimir; Bukhanov, Boris; Cheremisin, Alexey

    2018-04-03

    Injection of flue gas or CO 2 -N 2 mixtures into gas hydrate reservoirs has been considered as a promising option for geological storage of CO 2 . However, the thermodynamic process in which the CO 2 present in flue gas or a CO 2 -N 2 mixture is captured as hydrate has not been well understood. In this work, a series of experiments were conducted to investigate the dependence of CO 2 capture efficiency on reservoir conditions. The CO 2 capture efficiency was investigated at different injection pressures from 2.6 to 23.8 MPa and hydrate reservoir temperatures from 273.2 to 283.2 K in the presence of two different saturations of methane hydrate. The results showed that more than 60% of the CO 2 in the flue gas was captured and stored as CO 2 hydrate or CO 2 -mixed hydrates, while methane-rich gas was produced. The efficiency of CO 2 capture depends on the reservoir conditions including temperature, pressure, and hydrate saturation. For a certain reservoir temperature, there is an optimum reservoir pressure at which the maximum amount of CO 2 can be captured from the injected flue gas or CO 2 -N 2 mixtures. This finding suggests that it is essential to control the injection pressure to enhance CO 2 capture efficiency by flue gas or CO 2 -N 2 mixtures injection.

  16. The Relationship Between CO2 Levels and CO2 Related Symptoms Reported on the ISS

    Science.gov (United States)

    VanBaalen, M.; Law, J.; Foy, M.; Wear, M. L.; Mason, S.; Mendez, C.; Meyers, V.

    2014-01-01

    Medical Operations, Toxicology, and the Lifetime Surveillance of Astronaut Health collaborated to assess the association of CO2 levels on board the International Space Station and USOS crew reported symptoms inflight, i.e. headache and vision changes. Private Medical Conference (PMC) documents and the weekly Space Medicine Operations Team (SMOT) Notes were used to provide a robust data set of inflight medical events. All events and non-events were documented independent of CO2 levels and other potential contributors. Average (arithmetic mean) and single point maximum ppCO2 was calculated for the 24 hours and 7 days prior to the PMC or SMOT date and time provided by LSAH. Observations falling within the first 7 days of flight (147) were removed from the datasets analyzed to avoid confounding with Space Adaptation Syndrome. The final analysis was based on 1716 observations. For headache, 46 headaches were observed. CO2 level, age at launch, time inflight, and data source were all significantly associated with headache. In particular, for each 1 mmHg increase in CO2, the odds of a crewmember reporting a headache doubled. For vision changes, 29 reports of vision changes were observed. These observations were not found to be statistically associated with CO2 levels as analyzed. While the incidence of headache has was not high (3%), headaches may be an indicator of underlying increases in intracranial pressure, which may result likely from the synergy between CO2-induced cerebral vasodilatation and decreased venous drainage in microgravity. Vision changes were inconsistently reported and as a result did not align appropriately with the CO2 levels. Further analysis is needed. Our results support ongoing efforts to lower the CO2 exposure limits in spacecraft.

  17. Sustainable Concrete Performance—CO2-Emission

    Directory of Open Access Journals (Sweden)

    Rafal Latawiec

    2018-02-01

    Full Text Available The balance of carbon dioxide emissions and other greenhouse gases in the life cycle of concrete is one of the important elements affecting the sustainable development of concrete technology. Modifications in the composition in the aim of minimization of so-called “carbon footprint” of concrete also affect the majority of its technical features, including primarily the mechanical properties and durability. The article presents a desirability function that would allow us to estimate the combined effect of the modification in terms of both CO2 emissions and some of the technical features of the concrete. As criterial features equivalent CO2 emission, compressive strength and susceptibility/resistance to concrete carbonation are selected. Selected features should be considered as an example for the presentation of the proposed methodology and represent the three pillars of concrete desirability in terms of sustainable development, i.e., the constructional usefulness, durability, and environmental performance.

  18. National CO2 emissions trading in European perspective; Nationale CO2-emissiehandel in Europees perspectief

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    This report is the reaction of the Social and economic council (SER) in the Netherlands to the request of the Dutch Ministry of Housing, Spatial Planning en Environment (VROM) to formulate an advice on the final report of the Committee CO2 Trade (a.k.a the Vogtlander Committee). This Committee has drafted a proposal for a CO2 emission trade system in the Netherlands. The SER has also taken into account the proposal of the European Committee on a guideline for CO2 emission trade in the European Union (EU)

  19. Determinants of CO2 growth in Italy

    International Nuclear Information System (INIS)

    Cozzi, L.; Di Giulio, E.

    1999-01-01

    In order to obtain a clear understanding of the relationship between the Italian economy and CO 2 emissions in the 1975-1995 period, a sectorial decomposition analysis of emissions, based on Laspeyres index analysis, were calculated. Building on this analysis, qualitative reflections are made in order to individuate the more appropriate areas of action to respect the target that the Kyoto Protocol assigns to Italy [it

  20. Integration of CO2 assessment tools

    OpenAIRE

    van Noort, Martijn; Mahmod, Mohamed Kamil Morsi; Behrisch, Michael; Benz, Thomas

    2014-01-01

    The assessment of the CO2 impacts of ICT measures in transport requires a chain of software tools that need to be used in an integrated way. This paper reports on work performed in the Amitran project on a standard and an implementation for the assessment framework and interfaces that will enable researchers to easily combine these tools according to their preferences, and provides details on the implemented interfaces.

  1. Panorama 2016 - Chemical recycling of CO2

    International Nuclear Information System (INIS)

    Forti, Laurent; Fosse, Florian

    2015-12-01

    The ongoing rise of atmospheric carbon dioxide concentration is a major environmental and societal concern. Among the potential solutions for reducing carbon emissions in the energy sector, the chemical recycling of CO 2 has received considerable attention. Conversion of carbon dioxide into other recoverable substances offers the benefit of reducing the carbon footprint of newly developed products and of shifting away from the use of fossil resources. Various methods to create a wide range of products are currently being studied. (authors)

  2. Continuous CO2 extractor and methods

    International Nuclear Information System (INIS)

    2010-01-01

    The purpose of this CRADA was to assist in technology transfer from Russia to the US and assist in development of the technology improvements and applications for use in the U.S. and worldwide. Over the period of this work, ORNL has facilitated design, development and demonstration of a low-pressure liquid extractor and development of initial design for high-pressure supercritical CO2 fluid extractor.

  3. Continuous CO2 extractor and methods

    Energy Technology Data Exchange (ETDEWEB)

    None listed

    2010-06-15

    The purpose of this CRADA was to assist in technology transfer from Russia to the US and assist in development of the technology improvements and applications for use in the U.S. and worldwide. Over the period of this work, ORNL has facilitated design, development and demonstration of a low-pressure liquid extractor and development of initial design for high-pressure supercritical CO2 fluid extractor.

  4. Bifunctional Catalysts for CO2 Reduction

    Science.gov (United States)

    2014-09-30

    dioxide reduction catalysis . (SA 1 – Catalyst candidate synthesis) As outlined in the original proposal, ligand platforms have been synthesized to...was limited to outer-sphere electron transfer (necessary oxidation potentials for catalysis > –2.1 V vs. [Cp2Fe] +/0). Thus, we pursued two...high altitude air travel is the transportation of the fuel itself. Our targeted strategy is to transform CO2 into viable building blocks for synthetic

  5. CO2 capture takes its industrial turn

    International Nuclear Information System (INIS)

    Remoue, A.; Lutzky, A.

    2009-01-01

    The CO 2 capture and sequestration is entering the industrial era. The technologies are ready, the regulation is progressively put into action, the financing of demonstration facilities is unfreezing and companies are on the starting line from Canada to China, including the USA and Europe. The market takeoff is expected for 2015 but the competition is already hard between equipment manufacturers who wish to develop proprietary technologies. (J.S.)

  6. Towards Overhauser DNP in supercritical CO(2).

    Science.gov (United States)

    van Meerten, S G J; Tayler, M C D; Kentgens, A P M; van Bentum, P J M

    2016-06-01

    Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for (1)H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in (1)H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4T on high pressure superheated water and model systems such as toluene in high pressure CO2. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Martian Gullies: Formation by CO2 Fluidification

    Science.gov (United States)

    Cedillo-Flores, Y.; Durand-Manterola, H. J.

    2006-12-01

    Some of the geomorphological features in Mars are the gullies. Some theories developed tried explain its origin, either by liquid water, liquid carbon dioxide or flows of dry granular material. We made a comparative analysis of the Martian gullies with the terrestrial ones. We propose that the mechanism of formation of the gullies is as follows: In winter CO2 snow mixed with sand falls in the terrain. In spring the CO2 snow sublimate and gaseous CO2 make fluid the sand which flows like liquid eroding the terrain and forming the gullies. By experimental work with dry granular material, we simulated the development of the Martian gullies injecting air in the granular material. We present the characteristics of some terrestrial gullies forms at cold environment, sited at Nevado de Toluca Volcano near Toluca City, México. We compare them with Martian gullies choose from four different areas, to target goal recognize or to distinguish, (to identify) possible processes evolved in its formation. Also, we measured the lengths of those Martian gullies and the range was from 24 m to 1775 meters. Finally, we present results of our experimental work at laboratory with dry granular material.

  8. 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.

  9. Polymeric nanoporous materials fabricated with supercritical CO2 and CO2-expanded liquids.

    Science.gov (United States)

    Zhang, Aijuan; Zhang, Qingkun; Bai, Hua; Li, Lei; Li, Jun

    2014-01-01

    Both academia and industries have put great efforts into developing non-destructive technologies for the fabrication of polymeric nanoporous materials. Such non-destructive technologies developed with supercritical CO2 (scCO2) and CO2-expanded liquids (CXLs) have been attracting more and more attention because they have been demonstrated to be green and effective media for porous polymer preparation and processing. In this tutorial review, we present several such new technologies with scCO2 and CXLs, which have the capacity to prepare polymeric nanoporous materials with unique morphologies. The fabricated nanoporous polymers have significantly improved the performance of polymeric monoliths and films, and have found wide applications as templates, antireflection coatings, low-k materials, tissue engineering scaffolds and filtration membranes. This tutorial review also introduces the associated characterization methods, including the imaging, scattering and physisorption techniques.

  10. Biosequestration of atmospheric CO2 and flue gas-containing CO2 by microalgae.

    Science.gov (United States)

    Cheah, Wai Yan; Show, Pau Loke; Chang, Jo-Shu; Ling, Tau Chuan; Juan, Joon Ching

    2015-05-01

    The unceasing rise of greenhouse gas emission has led to global warming and climate change. Global concern on this phenomenon has put forward the microalgal-based CO2 sequestration aiming to sequester carbon back to the biosphere, ultimately reducing greenhouse effects. Microalgae have recently gained enormous attention worldwide, to be the valuable feedstock for renewable energy production, due to their high growth rates, high lipid productivities and the ability to sequester carbon. The photosynthetic process of microalgae uses atmospheric CO2 and CO2 from flue gases, to synthesize nutrients for their growth. In this review article, we will primarily discuss the efficiency of CO2 biosequestration by microalgae species, factors influencing microalgal biomass productions, microalgal cultivation systems, the potential and limitations of using flue gas for microalgal cultivation as well as the bio-refinery approach of microalgal biomass. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Natural Analogues of CO2 Geological Storage; Analogos Naturales del Almacenamiento Geologico de CO2

    Energy Technology Data Exchange (ETDEWEB)

    Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2007-07-20

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  12. A single-ligand ultra-microporous MOF for precombustion CO2 capture and hydrogen purification.

    Science.gov (United States)

    Nandi, Shyamapada; De Luna, Phil; Daff, Thomas D; Rother, Jens; Liu, Ming; Buchanan, William; Hawari, Ayman I; Woo, Tom K; Vaidhyanathan, Ramanathan

    2015-12-01

    Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate)2 with a cubic framework that exhibits exceptionally high CO2/H2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO2 adsorption-desorption cycling and has CO2 self-diffusivities of ~3 × 10(-9) m(2)/s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO2-CO2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams.

  13. A single-ligand ultra-microporous MOF for precombustion CO2 capture and hydrogen purification

    Science.gov (United States)

    Nandi, Shyamapada; De Luna, Phil; Daff, Thomas D.; Rother, Jens; Liu, Ming; Buchanan, William; Hawari, Ayman I.; Woo, Tom K.; Vaidhyanathan, Ramanathan

    2015-01-01

    Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate)2 with a cubic framework that exhibits exceptionally high CO2/H2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO2 adsorption-desorption cycling and has CO2 self-diffusivities of ~3 × 10−9 m2/s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO2-CO2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams. PMID:26824055

  14. Short-term CO2 exchange response to temperature, irradiance, and CO2 concentration in strawberry.

    Science.gov (United States)

    Campbell, D E; Young, R

    1986-01-01

    Relative importance of short-term environmental interaction and preconditioning to CO2 exchange response was examined in Fragaria ananasa (strawberry, cv. Quinault). Tests included an orthogonal comparison of 15 to 60-min and 6 to 7-h exposures to different levels of temperature (16 to 32°C), photosynthetically active radiation (PAR, 200 to 800 μE m(2) s(-1)), and CO2 (300 to 600 μl/l) on successive days of study. Plants were otherwise maintained at 21°C, 300 μE m(2) s(-1) PAR and 300-360 μl/l CO2 as standard conditions. Treatment was restricted to the mean interval of 14 h daily illumination and the first 3-4 days of each test week over a 12-week cultivation period. CO2 exchange rates were followed with each step-change in environmental level including ascending/descending temperature/PAR within a test period, initial response at standard conditions on successive days of testing, and measurement at reduced O2. Response generally supported prior concepts of leaf biochemical modeling in identifying CO2 fixation as the major site of environmental influence, while overall patterns of whole plant CO2 exchange suggested additional effects for combined environmental factors and preconditioning. These included a positive interaction between temperature and CO2 concentration on photosynthesis at high irradiance and a greater contribution by 'dark' respiration at lower PAR than previously indicated. The further importance of estimating whole plant CO2 exchange from repetitive tests and measurements was evidenced by a high correlation of response to prior treatment both during the daily test period and on consecutive days of testing.

  15. Recycling CO 2 ? Computational Considerations of the Activation of CO 2 with Homogeneous Transition Metal Catalysts

    KAUST Repository

    Drees, Markus

    2012-08-10

    Faced with depleting fossil carbon sources, the search for alternative energy carriers and energy storage possibilities has become an important issue. Nature utilizes carbon dioxide as starting material for storing sun energy in plant hydrocarbons. A similar approach, storing energy from renewable sources in chemical bonds with CO 2 as starting material, may lead to partial recycling of CO 2 created by human industrial activities. Unfortunately, currently available routes for the transformation of CO 2 involve high temperatures and are often not selective. With the development of more sophisticated methods and better software, theoretical studies have become both increasingly widespread and useful. This concept article summarizes theoretical investigations of the current state of the feasibility of CO 2 activation with molecular transition metal catalysts, highlighting the most promising reactions of CO 2 with olefins to industrially relevant acrylic acid/acrylates, and the insertion of CO 2 into metal-element bonds, particularly for the synthesis of cyclic carbonates and polymers. Rapidly improving computational power and methods help to increase the importance and accuracy of calculations continuously and make computational chemistry a useful tool helping to solve some of the most important questions for the future. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. CO2 capture by gas hydrate crystallization: Application on the CO2-N2 mixture

    International Nuclear Information System (INIS)

    Bouchemoua, A.

    2012-01-01

    CO 2 capture and sequestration represent a major industrial and scientific challenge of this century. There are different methods of CO 2 separation and capture, such as solid adsorption, amines adsorption and cryogenic fractionation. Although these processes are well developed at industrial level, they are energy intensive. Hydrate formation method is a less energy intensive and has an interesting potential to separate carbon dioxide. Gas hydrates are Document crystalline compounds that consist of hydrogen bonded network of water molecules trapping a gas molecule. Gas hydrate formation is favored by high pressure and low temperature. This study was conducted as a part of the SECOHYA ANR Project. The objective is to study the thermodynamic and kinetic conditions of the process to capture CO 2 by gas hydrate crystallization. Firstly, we developed an experimental apparatus to carry out experiments to determine the thermodynamic and kinetic formation conditions of CO 2 -N 2 gas hydrate mixture in water as liquid phase. We showed that the operative pressure may be very important and the temperature very low. For the feasibility of the project, we used TBAB (Tetrabutylammonium Bromide) as thermodynamic additive in the liquid phase. The use of TBAB may reduce considerably the operative pressure. In the second part of this study, we presented a thermodynamic model, based on the van der Waals and Platteeuw model. This model allows the estimation of thermodynamic equilibrium conditions. Experimental equilibrium data of CO 2 -CH 4 and CO 2 -N 2 mixtures are presented and compared to theoretical results. (author)

  17. Production of DHA by microalga; Bisai sorui ni yoru DHA seisan

    Energy Technology Data Exchange (ETDEWEB)

    Tatsuzawa, H.; Nishiwaki, E. [Ebara Research Co. Ltd., Kanagawa (Japan)

    1995-01-20

    By selecting the Pavlova lutheri CSIRO-182, marine microalga, as an object, its cultural condition was studied to synthesize the DHA (docosahexaenoic acid) which was regarded as an operator of physiological activation useful as a polyunsaturated fatty acid. Belonging to the Haptophyceae having flagella, the P. lutheri alga is being used as feed in the fish-rising industry. For the culture, the alga was made 15 and 25{degree}C, and 2500 to 15000 lx in temperature and optical intensity, respectively after putting a 1.5l cultural medium in the 2l flask. Air was fed at the rate of 1l/min through a filter having 0.2 micron m pores, which feeding aimed simultaneously at agitating the algae. In case of 2500 lx, it became steady in 7 days and 12 days at 25{degree}C and 15{degree}C, respectively, and was then recovered. Though its respective maximum numbers of stems did not differ, its EPA (eicosapentaenoic acid) content and DHA content per the total fatty acid at 15{degree}C became 1.4 times and 2.0 times, respectively as high as at 25{degree}C. Its total quantity of fatty acid per l, and EPA content and DHA content per total fatty acid at 10000 lx became 2.8 times, and 2.0 times and 2.5 times, respectively as large/high as at 2500 lx. 6 refs., 6 figs., 2 tabs.

  18. Measurement of crack in rock using transmitted elastic wave; Toka danseiha ni yoru ganbannai kiretsu keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Tomishima, Y. [National Institute for Resources and Environment, Tsukuba (Japan)

    1997-10-22

    With an objective to measure at high accuracy the positions and sizes of cracks existing in rocks, a theoretical study has been carried out on a method which utilizes initial movement characteristics of P-wave. The P-wave which diffracts and propagates at a crack tip has a characteristic that its phase may reverse according to the positional relationship between vibration transmitting and receiving points. This positional relationship is decided by the Poisson ratio of media alone. Therefore, when the P-wave is measured while the vibration transmitting and receiving points are moved sandwiching a crack, the polarity of received waveform is changed from negative to positive at a certain position as a boundary. In order to measure this change at high accuracy, an elastic wave of high frequency is required, but it is not easy to obtain the wave in situ. In contrast, utilizing the initial movement polarity can not only identify the change in the polarity, but also perform measurement at high accuracy. The present study discussed a case where cracks are parallel with a free surface and a case where the cracks have angles with the free surface, whereas it was shown that positions of the upper and lower tips of a crack, and length of the crack can be measured accurately. 4 refs., 5 figs.

  19. Foods hygiene management according to HACCP.; HACCP ni yoru shokuhin eisei kanri

    Energy Technology Data Exchange (ETDEWEB)

    Seki, T. [Niigata Enginering Co., Ltd., Tokyo (Japan)

    2000-11-01

    New foods hygiene management system HACCP(Hazard Analysis and Critical Control Point) was explained, which prevents food poisoning. Followings are described; (1) Outline of HACCP, (2) History of HAPPC, (3) Process to perform HACCP, (4) Infrastructure for HACCP, (5) How to promote HACCP, (6) Certification system in Japan. HACCP secures the safety in foods hygiene by making rules of Critical Control Points (CCP) on foods hygiene and by administrating strictly their performance. Details of works, frequency and person in charge of the work and methods to confirm and record the work are prescribed in PP (Prerequisite Program) and SSOP (Sanitation Standard Operation Procedure). (NEDO)

  20. Groundwater exploration by self-potential method; Shizen den`iho ni yoru chikasui tansa

    Energy Technology Data Exchange (ETDEWEB)

    Onaru, I.; Irie, S.; Mizunaga, H.; Ushijima, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1997-05-27

    This paper describes results measured from the field experiments and data analysis of the groundwater exploration by self-potential method. The field survey was conducted in the vicinity of spring water source in the suburbs of Fukuoka City. For the field experiments, potential differences from the standard potential electrode set at the distance about 200 m were measured at multi-points, simultaneously. For the laboratory experiments, assuming that the groundwater flows in a permeable layer, streaming potential change was observed against the changes of flow rate and electrical conductivity. Thus, the generation of streaming potential was investigated. For the experiment using specimens obtained at the spring water source, the potential changed to negative and was stabilized in around -80 mV after 15 minutes. Numerical simulation was conducted by means of the three-dimensional finite difference method using parameters obtained from the laboratory experiments. From these results, the groundwater flow image could be obtained. It was also confirmed that the self-potential observed in the spring water source area was caused by the streaming potential. 11 refs., 9 figs.

  1. 3D pre-stack time migration; Kiruhihoffuho ni yoru sanjigen jugo mae jikan migration shori

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Y.; Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsuru, T. [Japan National Oil Corp., Tokyo (Japan)

    1997-05-27

    This paper reports pre-stack migration in elastic wave exploration as to its algorithm and examples of processed data. The time migration processing hypothesizes that seismic waves propagate linearly. It calculates travel time by dividing the sum of the straight distance from a vibration transmitting point to an image point and the straight distance from the image point to a vibration receiving point with RMS velocity given as a parameter. To maintain the relative relation of amplitude sizes, the signal on an elliptic body is made smaller in inverse proportion to the size of that elliptic body. With regard to apparent interval of input trace as seen from the reflection surface, or with regard to density, the signal is made smaller by cos{theta} times. While this program deals with three-dimensional migration, its output turns out as an arbitrary two-dimensional plane. The program requires a huge amount of data processing, whereas a method is used, that the input trace is divided, each group is processed by using separate computers, and the results are summed up. 3 refs., 4 figs.

  2. Continuous gravity monitoring of geothermal activity; Renzoku juryoku sokutei ni yoru chinetsu katsudo no monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, M. [Geological Survey of Japan, Tsukuba (Japan)

    1997-05-27

    To clarify the geothermal activity in the geothermal fields in New Zealand, gravity monitoring was conducted using SCINTREX automatic gravimeter. The measurements were conducted between the end of January and the beginning of March, 1996. Firstly, continuous monitoring was conducted at the standard point for about ten days, and the tidal components were estimated from the records. After that, continuous monitoring was conducted at Waimangu area for several days. Continuous monitoring was repeated at the standard point, again. At the Waimangu area, three times of changes in the pulse-shape amplitude of 0.01 mgal having a width of several hours were observed. For the SCINTREX gravimeter, the inclination of gravimeter is also recorded in addition to the change of gravity. During the monitoring, the gravimeter was also inclined with the changes of gravity. This inclination was useful not only for the correction of gravity measured, but also for evaluating the ground fluctuation due to the underground pressure source. It is likely that the continuous gravity monitoring is the relatively conventional technique which is effective for prospecting the change of geothermal reservoir. 2 figs.

  3. Three dimensional wavefield modeling using the pseudospectral method; Pseudospectral ho ni yoru sanjigen hadoba modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T.; Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Saeki, T. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1997-05-27

    Discussed in this report is a wavefield simulation in the 3-dimensional seismic survey. With the level of the object of exploration growing deeper and the object more complicated in structure, the survey method is now turning 3-dimensional. There are several modelling methods for numerical calculation of 3-dimensional wavefields, such as the difference method, pseudospectral method, and the like, all of which demand an exorbitantly large memory and long calculation time, and are costly. Such methods have of late become feasible, however, thanks to the advent of the parallel computer. As compared with the difference method, the pseudospectral method requires a smaller computer memory and shorter computation time, and is more flexible in accepting models. It outputs the result in fullwave just like the difference method, and does not cause wavefield numerical variance. As the computation platform, the parallel computer nCUBE-2S is used. The object domain is divided into the number of the processors, and each of the processors takes care only of its share so that parallel computation as a whole may realize a very high-speed computation. By the use of the pseudospectral method, a 3-dimensional simulation is completed within a tolerable computation time length. 7 refs., 3 figs., 1 tab.

  4. Extraction of DNA by the reverse micelle; Gyaku miseru ni yoru DNA no chushutsu

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Masahiro [Kyushu University, Fukuoka (Japan). Graduate School; Ono, Tsutomu; Horiuchi, Akihiko; Furusaki, Shintaro

    1999-03-05

    Using the reverse micelle which consisted of the surfactant of the cations, it succeeded in DNA extraction of the salmon spermatozoon. The transfer of DNA formed in the isooctane from water phase to the reverse micelle is greatly dependent on type and ionic strength of the surfactant. By the surfactant of quaternary ammonium salt type with two long-chain alkyl units, the DNA which was charged anionic was efficiently extracted in the reverse micelle. (translated by NEDO)

  5. Maintaining mine roadway using rock bolts. Rock bolt ni yoru kodo iji

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, T. (Taiheiyo Coal Mining Co. Ltd., Tokyo (Japan))

    1992-11-01

    This paper describes the rock bolt method, devices and construction experiences in maintaining mine roadway drilling with Wombat-type rock bolt drilling and driving machines. Keeping the pace with coal mining zones reaching increasingly greater depths, timbering arch frames have grown larger and heavier, with frame intervals decreased. The described method was adopted to improve work efficiency and save manpowers. The Wombat, 1200-90 machine uses a driving air pressure at 7 kgf/cm[sup 2] a torque at 170 N/m to 180 N/m, and a free rotation at 800 rpm, consumes a r at 60 L/S, weighs 38 kg., and measures 1,370 mm to 3,420 mm in length. The machine is scheduled for use with three gates placed at a depth below sea level as deep as about 600 m, with gate diameters from about 5.0 m to 5.5 m and a length of about 8000 m. Effectiveness and safety of the rock bolts were verified using an extensometer made in the U.S.A. Roof subsidence after a working face has been drilled to 20 m to 30 m was about one third of that when no rock bolts were used, thus the adaptability of the method was verified. Although the drilling technique using the Wombat machine has taken roots at this particular coal mine, problems still remain such as in workability, for which further efficiency improvement and manpower saving are desired. 4 figs., 3 tabs.

  6. Reaction mechanism of catalytic reduction of NO by urea. Nyoso ni yoru sesshoku dassho hanno kiko

    Energy Technology Data Exchange (ETDEWEB)

    Tachi, T.; Kato, A.; Yamashita, H. (Hitachi, Ltd., Tokyo (Japan))

    1992-08-10

    Discussion was given on NH[sub 3] substituting reducing agents used in contact reduction process for NO[sub x] discharged from fossil fuels. The selected reducing agents are odorless and highly stable urea, cianuric acid, meramine, and biuret. An MoO[sub 2]carried TiO[sub 2]catelyst was used. The experiment was performed at a temperature ranging from 250[degree]C to 500[degree]C and a space velocity from 1000 h[sup [minus]1] to 120000 h[sup [minus]1] using simulated discharge gases. The findings from the experiment are summarized as follows: All of the reducing agents showed denitration capability equivalent to that with NH[sub 3]; discussions of reaction amount theory on highly practicable urea revealed that the urea and NO react at a molar ratio of 1:2; the urea is hydrolyzed into NH[sub 3] and CO[sub 3] under the presence of steam, and the generated NH[sub 3]involves in the denitrating reaction; catalyst surface adsorption species were discussed using FT-IR, whereas the catalyst contacted with vaporized urea exhibited NH[sub 4][sup +] specie on Bronsted acid site. The specie disappeared when NO was flown through. The result suggests that NO reacts with the NH[sub 3] adsorption specie generated on the catalyst. 6 refs., 7 figs., 1 tab.

  7. Countermeasures for increasing sequence continuous casting; Renchu kinosei taikabutsu zaishitsu, kozo kaizen ni yoru renrenchusu kojosaku

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, Masato; Shinagawa, Hiroaki; Kamada, Ryuji; Hiraga, Yutaka; Hara, Takayasu [Nippon Steel Corp., Tokyo (Japan)

    1999-06-01

    In the second continuous casting line of Kure Iron Works, Nisshin Steel Co., Ltd. improvement of the continuous casting counts per tundish was attempted for a target of max. 20. The results are as follows: (1) Non-SiO{sub 2} conversion of material for the long nozzle immersed part: About 20% improvement of durability compared with a conventional material to clear 0.059 mm/min of the targeted erosion speed when 20 CCC/TD is realized, (2) Durability improvement of SN plate: About 20% durability improvement was attained compared with a conventional material by the adoption of a non-SiO{sub 2} material, (3) Erosion resistance improvement of the immersed nozzle slug line part: Castable period was extended to 1 ch life improvement by increasing zirconia content, (4) Rise of stopper full open position: The rise of the full open position produced less variation of melt level than the conventional structure without increase of the SN opening, enabling plugging prevention between the stopper head and the upper nozzle which was an objective of this improvement, (5) Structure improvement of the upper nozzle: This improvement successfully prevented leaks from damage of the casting stop nozzle metal case and enabled casting under low gas flow even in TD nozzle plugging. These improvements gave a possibility to achieve max. 20 CCC/TD. (NEDO)

  8. Development of plastic pulley by injection molding; Shashutsu keisei ni yoru jushi pulley no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizumi, F.; Funatsu, A.; Yazawa, H. [Sumitomo Bakelite Co. Ltd., Tokyo (Japan)

    1997-10-01

    We developed plastic pulley for automobile manufactured by injection molding which will reduce manufacturing cost. We have developed product design, injection molding technology especially to improve mechanical strength and phenolic molding compound with good wear resistance and high mechanical strength. We have established `Injection Compression molding` technology to improve mechanical strength of weld portion. We also developed phenolic molding compound which is composed of one step resin and long organic fiber to obtain good wear resistance and high mechanical strength. Manufacturing cost will be reduced by using injection molding combined with lower material cost of the newly developed compound. 12 figs., 2 tabs.

  9. Characterization of earthquake fault by borehole experiments; Koseinai sokutei ni yoru jishin danso no kenshutsu

    Energy Technology Data Exchange (ETDEWEB)

    Ito, H.; Miyazaki, T.; Nishizawa, O.; Kuwahara, Y.; Kiguchi, T. [Geological Survey of Japan, Tsukuba (Japan)

    1996-05-01

    A borehole was excavated to penetrate the Nojima fault at the Hirabayashi area, to investigate the underground structures of the fault by observation of the cores and well logging. The borehole was excavated from 74.6m east of the fault surface. Soil is of granodiorite from the surface, and fault clay at a depth in a range from 624.1 to 625.1m. Observation of the cores, collected almost continuously, indicates that the fault fracture zone expands in a depth range from 557 to 713.05m. The well logging experiments are natural potential, resistivity, density, gamma ray, neutron, borehole diameter, microresistivity and temperature. They are also for DSI- and FMI-observation, after expansion of the borehole. The well logging results indicate that resistivity, density and elastic wave velocity decrease as distance from fault clay increases, which well corresponds to the soil conditions. The BHTV and FMI analyses clearly detect the fault clay demarcations, and show that elastic wave velocity and BHTV results differ at above and below the fault. 3 refs., 3 figs.

  10. Seismic traveltime tomography by use of gridpoints discritization; Koshitenho ni yoru danseiha tomography kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, T.; Watanabe, T.; Sassa, K. [Kyoto University, Kyoto (Japan). Faculty of Engineering

    1996-05-01

    Efforts were made to enhance analytical precision and stabilize the results in seismic traveltime tomography by use of a method wherein the velocity distribution is expressed as a continuous function interpolated by parameters respectively assigned to the gridpoints. In this method, the slowness data are regarded as the parameters respectively assigned to the gridpoints, and the slowness value at a given point is determined after interpolation by the gridpoints surrounding the said point. A method based on the variation principle was used for ray tracing. As the result, it was confirmed that this method determines the ray path and traveltime with high precision. A method of least squares using Lagrange`s multiplier was applied for inversion. Comparison was made between the use of cells and the use of gridpoints in the results of inversions performed for an inclined 4-layer structure model, when it was found that the values involving the boundaries between layers, inclinations of the layers, and velocities of seismic waves are ambiguous with the cells while those with the gridpoints are reconstructed roughly correctly. 5 refs., 7 figs., 1 tab.

  11. Ground water contamination by electrical prospecting; Denki tansaho ni yoru chikasui osen chosa

    Energy Technology Data Exchange (ETDEWEB)

    Irie, S.; Fujii, Y.; Sakaguchi, S.; Ushijima, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1996-05-01

    A report is made about the result of vertical electric sounding conducted in the MK district, Fukuoka City, where Kyushu University is about to move. As for the method of electrical prospecting, in consideration of the need for probing a depth of 50m at the shallowest, vertical electrical sounding with a Schlumberger array of electrodes was employed. Measurements were made for 57 locations on the planar ground, the interval between electrodes gradually increased from 1 to 200m. In the 2D structure model analysis, a 2D inversion program was utilized in the ABIC minimization method. Also investigated were the relationship of electric prospecting and the geology, geological conditions, water level in the well, water quality, salt water, and pore rate from the previously-conducted investigative boring. As the result, it was estimated that the boundary between the first and second layers detected by electric prospecting reflected the level of underground water and that the boundary between the second and third layers reflected the portion where the N-value sharply increases. 4 refs., 8 figs.

  12. Archaeological prospecting by DEF method; Denkai zansaho ni yoru iseki tansa

    Energy Technology Data Exchange (ETDEWEB)

    Kishikawa, H.; Aono, T.; Tanaka, T.; Mizunaga, H. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1996-05-01

    A study is made of a newly-developed differential electric field (DEF) method, wherein potentials between potential electrodes equidistant from a current electrode is measured for directly detecting the secondary potential attributable to an anomalous-resistivity body. In this method, a current is fed into the ground from a point source C1, and four potential electrodes, two each on the X-axis and Y-axis, are provided equidistant from the point source C1 for the measurement of the potentials in the directions of X and Y. Numerical experiments and field experiments in a playground were conducted for this DEF method, and it was found that this method is effective in detecting an anomalous-resistivity bodies (ruins, etc.) situated in a homogeneous medium or in a horizontal multi-layer structure, is capable of displaying anomalous vectors enabling the estimation of the direction from the observation point of the anomalous-resistivity body, improves on work efficiency over the conventional mapping method, enables the estimation of the boundary of the anomalous-resistivity body on the basis of the peak of the anomalous electric field residue on the display, and that the obtained data can be easily processed by use of a personal computer on the site. 3 refs., 9 figs.

  13. Faults survey by 3D reflection seismics; Sanjigen hanshaho jishin tansa ni yoru danso chosa

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, T.; Ejiri, T.; Yamada, N.; Narita, N.; Aso, H.; Takano, H.; Matsumura, M. [Dia Consultants Company, Tokyo (Japan)

    1996-10-01

    This paper describes fault survey by 3D seismic reflection exploration. Survey has been conducted mainly at flat land area without pavement not in urban area in Japan. Subsurface structure is complicated with intersecting multiple faults. In this area, a lot of geological investigations have been done prior to the seismic reflection exploration. Fairly certain images of faults have been obtained. However, there were still unknown structures. Survey was conducted at an area of 170m{times}280m in the CDP range. Measurements were carried out by using 100 g of dynamite per seismic generation point combined with 40 Hz velocity geophones. Fixed distribution consisting of lattice points of 12{times}12 was adopted as an observation method. In and around the lattice, a great number of explosions were carried out. The CDP stacking method and the method of migration after stacking were used for the data processing. The 3D structures of six horizons and five faults could be interpreted. Interpreted horizons were well agreed with the logging results. 3 figs.

  14. FY1995 community support by mobile agents; 1995 nendo mobile agent ni yoru community keisei shien

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The purpose is to develop fundamental technologies for navigation systems and mobile computing systems in museums, theme parks and cities. Concretely, we implement software agents into the mobile computing environment which consists of PHS, mobile computers and mobile robots, and realize various functions to access regional information. We have studied on Communityware which supports human activities and communities by using mobile agents implemented into mobile computers and town robots. The mobile agents, which intelligently process information obtained in physical and virtual worlds, access regional information which is omnipresent in the environment. With respect to the approach using mobile computers, we have provided one hundred mobile computers in the international conference on multiagent systems 1996 and carried out the first experimentation of mobile computing in the world. The mobile computer has two functions: Community Viewer which displays interactions between members of communities and Social Matchmaker which supports to hold meetings by searching for people who have common interests. With respect to the approach using town robots, we have developed a robot system which can robustly behave in a complex outdoor environment by using vision agents embedded in the environment. The system aims at support of people in streets. (NEDO)

  15. Laser material purification of neodymium. Hikari reiki seiseiho ni yoru neodymium no kojundoka

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Y.; Ozaki, T.; Yoshimatsu, S. (National Research Institute for Metals, Tokyo (Japan)); Chiba, K.; Umeda, H.; Saeki, M. (Nippon Steel Corp., Tokyo (Japan))

    1991-05-20

    Selective photoexcitation and photoionization of neodymium atoms were studied basically by using laser. Also, using their properties, feasibility of laser material purification (LPM) technology in gaseous phase was presented. In the selective 3-step ionization, laser beam with two kinds of proper wave length causes resonance exitation of the target element, which goes up to the excitation level of the first step, and the element is ionized by the second laser beam and the third laser beam. The 3-step ionization scheme by a single wave length laser beam of 577.612nm was used for the ionization of Nd. Nd ionized selectively by laser beam was recovered as thin layer at the negative potential side of plane electrodes placed at both sides of the laser irradiation area. In the layer formed by the TPD technology with this scheme, it is possible to decrease impuritis such as Pr by 1/16 and to form highly purified thin layer. 13 refs., 12 figs., 1 tab.

  16. Surface photo reaction processes using synchrotron radiation; Hoshako reiki ni yoru hyomenko hanno process

    Energy Technology Data Exchange (ETDEWEB)

    Imaizumi, Y. [Tohoku University, Sendai (Japan). Institute for Materials Research; Yoshigoe, A. [Toyohashi University of Technology, Aichi (Japan); Urisu, T. [Toyohashi University of Technology, Aichi (Japan). Institute for Molecular Science

    1997-08-20

    This paper introduces the surface photo reaction processes using synchrotron radiation, and its application. A synchrotron radiation process using soft X-rays contained in electron synchrotron radiated light as an excited light source has a possibility of high-resolution processing because of its short wave length. The radiated light can excite efficiently the electronic state of a substance, and can induce a variety of photochemical reactions. In addition, it can excite inner shell electrons efficiently. In the aspect of its application, it has been found that, if radiated light is irradiated on surfaces of solids under fluorine-based reaction gas or Cl2, the surfaces can be etched. This technology is utilized practically. With regard to radiated light excited CVD process, it may be said that anything that can be deposited by the ordinary plasma CVD process can be deposited. Its application to epitaxial crystal growth may be said a nano processing application in thickness direction, such as forming an ultra-lattice structure, the application being subjected to expectation. In micromachine fabricating technologies, a possibility is searched on application of a photo reaction process of the radiated light. 5 refs., 6 figs.

  17. Fault structure analysis by means of large deformation simulator; Daihenkei simulator ni yoru danso kozo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Y.; Shi, B. [Geological Survey of Japan, Tsukuba (Japan); Matsushima, J. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

    1997-05-27

    Large deformation of the crust is generated by relatively large displacement of the mediums on both sides along a fault. In the conventional finite element method, faults are dealt with by special elements which are called joint elements, but joint elements, elements microscopic in width, generate numerical instability if large shear displacement is given. Therefore, by introducing the master slave (MO) method used for contact analysis in the metal processing field, developed was a large deformation simulator for analyzing diastrophism including large displacement along the fault. Analysis examples were shown in case the upper basement and lower basement were relatively dislocated with the fault as a boundary. The bottom surface and right end boundary of the lower basement are fixed boundaries. The left end boundary of the lower basement is fixed, and to the left end boundary of the upper basement, the horizontal speed, 3{times}10{sup -7}m/s, was given. In accordance with the horizontal movement of the upper basement, the boundary surface largely deformed. Stress is almost at right angles at the boundary surface. As to the analysis of faults by the MO method, it has been used for a single simple fault, but should be spread to lots of faults in the future. 13 refs., 2 figs.

  18. PLAINS CO2 REDUCTION (PCOR) PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; Daniel J. Daly; Lynette L. de Silva; John A. Harju; Melanie D. Jensen; Erin M. O' Leary; Wesley D. Peck; Steven A. Smith; James A. Sorensen

    2006-01-01

    During the period of October 1, 2003, through September 30, 2005, the Plains CO2 Reduction (PCOR) Partnership, identified geologic and terrestrial candidates for near-term practical and environmentally sound carbon dioxide (CO2) sequestration demonstrations in the heartland of North America. The PCOR Partnership region covered nine states and three Canadian provinces. The validation test candidates were further vetted to ensure that they represented projects with (1) commercial potential and (2) a mix that would support future projects both dependent and independent of CO2 monetization. This report uses the findings contained in the PCOR Partnership's two dozen topical reports and half-dozen fact sheets as well as the capabilities of its geographic information system-based Decision Support System to provide a concise picture of the sequestration potential for both terrestrial and geologic sequestration in the PCOR Partnership region based on assessments of sources, sinks, regulations, deployment issues, transportation, and capture and separation. The report also includes concise action plans for deployment and public education and outreach as well as a brief overview of the structure, development, and capabilities of the PCOR Partnership. The PCOR Partnership is one of seven regional partnerships under Phase I of the U.S. Department of Energy National Energy Technology Laboratory's Regional Carbon Sequestration Partnership program. The PCOR Partnership, comprising 49 public and private sector members, is led by the Energy & Environmental Research Center at the University of North Dakota. The international PCOR Partnership region includes the Canadian provinces of Alberta, Saskatchewan, and Manitoba and the states of Montana (part), Wyoming (part), North Dakota, South Dakota, Nebraska, Missouri, Iowa, Minnesota, and Wisconsin.

  19. Atmospheric CO2 from fossil plant cuticles.

    Science.gov (United States)

    Kerp, Hans

    2002-01-03

    Plants respond to changes in atmospheric carbon dioxide levels by regulating the number of stomata in their leaves. In his reconstruction of a continuous, 300-million-year record of atmospheric CO2, Retallack bases his curve on stomatal counts of fossil plant cuticles taken from published micrographs. However, the preservation of cuticles from Permian times is generally too fragmentary for the stomatal index to be reliably determined, the micrographs used could have biased the results, and there are important errors in the supplementary data - all of which cast doubt on the Permian part of Retallack's record.

  20. Childhood asthma and anthropogenic CO2 emissions

    Directory of Open Access Journals (Sweden)

    Dosanjh A

    2011-10-01

    Full Text Available Amrita DosanjhPediatric Pulmonologist, San Diego, California, USATrends in the incidence of childhood asthma worldwide have paralleled the sharp increase in carbon dioxide (CO2 emissions, over at least the last two decades. The prevalence of asthma in the United States has quadrupled over the last 20 years in part due to climate-related factors. In a report released by Harvard Medical School and the Center for Health and the Global Environment, it was noted that there was an increase in asthma incidence of 160% from 1980–1994 among preschool children.  

  1. Photosynthesis and Plant Growth at Elevated Levels of CO_2

    OpenAIRE

    Amane, Makino; Tadahiko, Mae; Department of Applied Plant Science, Graduate School of Agricultural Sciences, Tohoku University; Department of Applied Plant Science, Graduate School of Agricultural Sciences, Tohoku University

    1999-01-01

    In this review, we discuss the effects of elevated CO_2 levels on photosynthesis in relation to the whole plant growth in terrestrial higher C_3 plants. Short-term CO_2 enrichment stimulates the rate of phtosynthesis. Plant mass is also enhanced by CO_2 enrichment. However, the effects of long-term CO_2 enrichment on photosynthesis are variable. Generally, the prolonged exposure to CO_2 enrichment reduces the initial stimulation of photosynthesis in many spesies, and frequently suppresses pho...

  2. Saturated CO2 inhibits microbial processes in CO2-vented deep-sea sediments

    Science.gov (United States)

    de Beer, D.; Haeckel, M.; Neumann, J.; Wegener, G.; Inagaki, F.; Boetius, A.

    2013-08-01

    This study focused on biogeochemical processes and microbial activity in sediments of a natural deep-sea CO2 seepage area (Yonaguni Knoll IV hydrothermal system, Japan). The aim was to assess the influence of the geochemical conditions occurring in highly acidic and CO2 saturated sediments on sulfate reduction (SR) and anaerobic methane oxidation (AOM). Porewater chemistry was investigated from retrieved sediment cores and in situ by microsensor profiling. The sites sampled around a sediment-hosted hydrothermal CO2 vent were very heterogeneous in porewater chemistry, indicating a complex leakage pattern. Near the vents, droplets of liquid CO2 were observed emanating from the sediments, and the pH reached approximately 4.5 in a sediment depth > 6 cm, as determined in situ by microsensors. Methane and sulfate co-occurred in most sediment samples from the vicinity of the vents down to a depth of 3 m. However, SR and AOM were restricted to the upper 7-15 cm below seafloor, although neither temperature, low pH, nor the availability of methane and sulfate could be limiting microbial activity. We argue that the extremely high subsurface concentrations of dissolved CO2 (1000-1700 mM), which disrupt the cellular pH homeostasis, and lead to end-product inhibition. This limits life to the surface sediment horizons above the liquid CO2 phase, where less extreme conditions prevail. Our results may have to be taken into consideration in assessing the consequences of deep-sea CO2 sequestration on benthic element cycling and on the local ecosystem state.

  3. Saturated CO2 inhibits microbial processes in CO2-vented deep-sea sediments

    Directory of Open Access Journals (Sweden)

    D. de Beer

    2013-08-01

    Full Text Available This study focused on biogeochemical processes and microbial activity in sediments of a natural deep-sea CO2 seepage area (Yonaguni Knoll IV hydrothermal system, Japan. The aim was to assess the influence of the geochemical conditions occurring in highly acidic and CO2 saturated sediments on sulfate reduction (SR and anaerobic methane oxidation (AOM. Porewater chemistry was investigated from retrieved sediment cores and in situ by microsensor profiling. The sites sampled around a sediment-hosted hydrothermal CO2 vent were very heterogeneous in porewater chemistry, indicating a complex leakage pattern. Near the vents, droplets of liquid CO2 were observed emanating from the sediments, and the pH reached approximately 4.5 in a sediment depth > 6 cm, as determined in situ by microsensors. Methane and sulfate co-occurred in most sediment samples from the vicinity of the vents down to a depth of 3 m. However, SR and AOM were restricted to the upper 7–15 cm below seafloor, although neither temperature, low pH, nor the availability of methane and sulfate could be limiting microbial activity. We argue that the extremely high subsurface concentrations of dissolved CO2 (1000–1700 mM, which disrupt the cellular pH homeostasis, and lead to end-product inhibition. This limits life to the surface sediment horizons above the liquid CO2 phase, where less extreme conditions prevail. Our results may have to be taken into consideration in assessing the consequences of deep-sea CO2 sequestration on benthic element cycling and on the local ecosystem state.

  4. Effects of CO2 solubility on the long-term fate of CO2 sequestered in a saline aquifer

    NARCIS (Netherlands)

    Meer, L.G.H. van der; Wees, J.D. van

    2006-01-01

    Sequestering CO2 in aquifers is an attractive option for reducing CO2 emissions into the atmosphere. The success of CO2 sequestration during the Statoil Sleipner injection project proves that under the right conditions large volumes of CO2 can be stored in a water-bearing subsurface formation. In

  5. Reconsideration of atmospheric CO2 lifetime: potential mechanism for explaining CO2 missing sink

    Science.gov (United States)

    Kikuchi, R.; Gorbacheva, T.; Gerardo, R.

    2009-04-01

    Carbon cycle data (Intergovernmental Panel on Climate Change 1996) indicate that fossil fuel use accounts for emissions to the atmosphere of 5.5±0.5 GtC (Gigatons of carbon) annually. Other important processes in the global CO2 budget are tropical deforestation, estimated to generate about 1.6±1.0 GtC/yr; absorption by the oceans, removing about 2.0±0.8 GtC/yr; and regrowth of northern forests, taking up about 0.5±0.5 GtC/yr. However, accurate measurements of CO2 show that the atmosphere is accumulating only about 3.3±0.2 GtC/yr. The imbalance of about 1.3±1.5 GtC/yr, termed the "missing sink", represents the difference between the estimated sources and the estimated sinks of CO2; that is, we do not know where all of the anthropogenic CO2 is going. Several potential mechanisms have been proposed to explain this missing carbon, such as CO2 fertilization, climate change, nitrogen deposition, land use change, forest regrowth et al. Considering the complexity of ecosystem, most of ecosystem model cannot handle all the potential mechanisms to reproduce the real world. It has been believed that the dominant sink mechanism is the fertilizing effects of increased CO2 concentrations in the atmosphere and the addition to soils of fixed nitrogen from fossil-fuel burning and agricultural fertilizers. However, a recent analysis of long-term observations of the change in biomass and growth rates suggests that such fertilization effects are much too small to explain more than a small fraction of the observed sink. In addition, long-term experiments in which small forest patches and other land ecosystems have been exposed to elevated CO2 levels for extended periods show a rapid decrease of the fertilization effect after an initial enhancement. We will explore this question of the missing sink in atmospheric CO2 residence time. Radioactive and stable carbon isotopes (13-C/12-C) show the real CO2 lifetime is about 5 years; i.e. CO2 is quickly taken out of the atmospheric

  6. Global CO2 emissions from cement production

    Science.gov (United States)

    Andrew, Robbie M.

    2018-01-01

    The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 Gt CO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831455.

  7. Public Acceptance for Geological CO2-Storage

    Science.gov (United States)

    Schilling, F.; Ossing, F.; Würdemann, H.; Co2SINK Team

    2009-04-01

    Public acceptance is one of the fundamental prerequisites for geological CO2 storage. In highly populated areas like central Europe, especially in the vicinity of metropolitan areas like Berlin, underground operations are in the focus of the people living next to the site, the media, and politics. To gain acceptance, all these groups - the people in the neighbourhood, journalists, and authorities - need to be confident of the security of the planned storage operation as well as the long term security of storage. A very important point is to show that the technical risks of CO2 storage can be managed with the help of a proper short and long term monitoring concept, as well as appropriate mitigation technologies e.g adequate abandonment procedures for leaking wells. To better explain the possible risks examples for leakage scenarios help the public to assess and to accept the technical risks of CO2 storage. At Ketzin we tried the following approach that can be summed up on the basis: Always tell the truth! This might be self-evident but it has to be stressed that credibility is of vital importance. Suspiciousness and distrust are best friends of fear. Undefined fear seems to be the major risk in public acceptance of geological CO2-storage. Misinformation and missing communication further enhance the denial of geological CO2 storage. When we started to plan and establish the Ketzin storage site, we ensured a forward directed communication. Offensive information activities, an information centre on site, active media politics and open information about the activities taking place are basics. Some of the measures were: - information of the competent authorities through meetings (mayor, governmental authorities) - information of the local public, e.g. hearings (while also inviting local, regional and nation wide media) - we always treated the local people and press first! - organizing of bigger events to inform the public on site, e.g. start of drilling activities (open

  8. Wheat response to CO2 enrichment: CO2 exchanges transpiration and mineral uptakes

    Science.gov (United States)

    Andre, M.; Ducloux, H.; Richaud, C.

    1986-01-01

    When simulating canopies planted in varied densities, researchers were able to demonstrate that increase of dry matter production by enhancing CO2 quickly becomes independant of increase of leaf area, especially above leaf area index of 2; dry matter gain results mainly from photosynthesis stimulation per unit of surface (primary CO2 effect). When crop density is low (the plants remaining alone a longer time), the effects of increasing leaf surface (tillering, leaf elongation here, branching for other plants etc.) was noticeable and dry matter simulation factor reached 1.65. This area effect decreased when canopy was closed in, as the effect of different surfaces no longer worked. The stimulation of photosynthesis reached to the primary CO2 effect. The accumulation in dry matter which was fast during that phase made the original weight advantage more and more neglectible. Comparison with short term measurements showed that first order long term effect of CO2 in wheat is predictible with short term experiment, from the effect of CO2 on photosynthesis measured on reference sample.

  9. Effect of CO2 partial pressure and different CO2 phases on carbon steel corrosion

    Science.gov (United States)

    Mahlobo, MGR; Premlall, K.; Olubambi, PA

    2017-12-01

    Carbon capture and storage (CCS) is the recent promising technology aimed at reducing greenhouse gas emission. Like many other developed technologies, CCS is faced with great challenges such as pipeline transportation failure due to corrosion. There are many factors contributing to steel corrosion during the pipeline transportation of carbon dioxide (CO2). This study focuses on CO2 partial pressure and different phases of CO2 as some of the factors contributing to steel corrosion. Carbon steel was used as a testing specimen. High pressure reactor was used in this study to compress CO2 from low to high pressures ultimately changing the CO2 from gaseous phase to gas/liquid phase (subcritical) and to dense phase (supercritical). Weight loss method was employed to determine the corrosion rate while scanning electron microscopy (SEM) and X-Ray diffraction (XRD) were used to study the carbon steel morphology and phase analysis. Using low magnification digital camera, the type of corrosion that took place on the carbon steel surface was identified.

  10. A review of dry (CO2) reforming of methane over noble metal catalysts.

    Science.gov (United States)

    Pakhare, Devendra; Spivey, James

    2014-11-21

    Dry (CO2) reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. This reaction produces syngas that can be used to produce a wide range of products, such as higher alkanes and oxygenates by means of Fischer-Tropsch synthesis. DRM is inevitably accompanied by deactivation due to carbon deposition. DRM is also a highly endothermic reaction and requires operating temperatures of 800-1000 °C to attain high equilibrium conversion of CH4 and CO2 to H2 and CO and to minimize the thermodynamic driving force for carbon deposition. The most widely used catalysts for DRM are based on Ni. However, many of these catalysts undergo severe deactivation due to carbon deposition. Noble metals have also been studied and are typically found to be much more resistant to carbon deposition than Ni catalysts, but are generally uneconomical. Noble metals can also be used to promote the Ni catalysts in order to increase their resistance to deactivation. In order to design catalysts that minimize deactivation, it is necessary to understand the elementary steps involved in the activation and conversion of CH4 and CO2. This review will cover DRM literature for catalysts based on Rh, Ru, Pt, and Pd metals. This includes the effect of these noble metals on the kinetics, mechanism and deactivation of these catalysts.

  11. A Review on Bimetallic Nickel-Based Catalysts for CO2Reforming of Methane.

    Science.gov (United States)

    Bian, Zhoufeng; Das, Sonali; Wai, Ming Hui; Hongmanorom, Plaifa; Kawi, Sibudjing

    2017-11-17

    In recent years, CO 2 reforming of methane (dry reforming of methane, DRM) has become an attractive research area because it converts two major greenhouse gasses into syngas (CO and H 2 ), which can be directly used as fuel or feedstock for the chemical industry. Ni-based catalysts have been extensively used for DRM because of its low cost and good activity. A major concern with Ni-based catalysts in DRM is severe carbon deposition leading to catalyst deactivation, and a lot of effort has been put into the design and synthesis of stable Ni catalysts with high carbon resistance. One effective and practical strategy is to introduce a second metal to obtain bimetallic Ni-based catalysts. The synergistic effect between Ni and the second metal has been shown to increase the carbon resistance of the catalyst significantly. In this review, a detailed discussion on the development of bimetallic Ni-based catalysts for DRM including nickel alloyed with noble metals (Pt, Ru, Ir etc.) and transition metals (Co, Fe, Cu) is presented. Special emphasis has been provided on the underlying principles that lead to synergistic effects and enhance catalyst performance. Finally, an outlook is presented for the future development of Ni-based bimetallic catalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. The Influence of CO2 Solubility in Brine on Simulation of CO2 Injection into Water Flooded Reservoir and CO2 WAG

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan

    2010-01-01

    Injection of CO2 into depleted oil reservoirs is not only a traditional way to enhance oil recovery but also a relatively cheaper way to sequester CO2 underground since the increased oil production can offset some sequestration cost. CO2 injection process is often applied to water flooded...... reservoirs and in many situations alternating injection of water and CO2 is required to stabilize the injection front. Both scenarios involve a large amount of water, making CO2 solubility in brine, which is around ten times higher than methane solubility, a non-negligible factor in the relevant reservoir...... simulations. In our previous study, a 1-D slimtube simulator, which rigorously accounts for both CO2 solubility in brine and water content in hydrocarbon phases using the Peng-Robinson EoS modified by Soreide and Whitson, has been used to investigate the influence of CO2 solubility on the simulation...

  13. The magnetic hyperfine field in the 181Ta site in the Co2HfAl and Co2HfGa Heusler alloys

    International Nuclear Information System (INIS)

    Silva, R. da.

    1979-01-01

    The hyperfine magnetic fields at 181 Ta nuclei in Heusler alloys Co 2 HfZ (Z=Al, Ga) have been measured using the time differential perturbed gamma-gamma angular correlation (TDPAC) method. The hyperfine fields obtained from these measurements at the liquid nitrogen temperature are -189 and +- 150 kOersted for Co 2 HfAl and Co 2 HfGa, respectively. The concept that the hyperfine field at the Y site is similar to the solute fields in Fe, Co, Ni and Gd matrices is corroborated. We have verified that ratios H sub(hf) sub(Ta)/T sub(c) and H sub(hf) sub(Ta)μ sub(Co) in Co 2 HfZ compounds (Z=Al, Ga, Sn) do not depend on the nature of Z element. However a dependence in the value of observed field with the s-p element in Z site was noticed. We feel that the samples are not completely ordered cubic as observed by the quadrupole interaction measurements. The results are interpreted in terms of the Campbell-Blandin formalism, and it is shown that the spin polarization of conduction electrons at Hf and Ta have opposite signs. (Author) [pt

  14. CO2 store: the Valleys case study on CO2 capture, transport and storage

    International Nuclear Information System (INIS)

    2006-01-01

    This report summarises results of a study of the potential to capture and store underground the emissions from the proposed Valleys power plant, a 450MW IGCC plant, fuelled by a mixture of petroleum coke (petcoke) and locally mined anthracite, to be constructed at Onllwyn, near Drym, in the South Wales Coalfield. The study is based upon 85% of the total carbon dioxide (CO 2 ) emissions, approximately 2.45 million tonnes of CO 2 per year, being captured annually from the Valleys power plant, compressed to 110bar pressure and sent by pipeline for storage in an underground geological reservoir. Fitted for CO 2 capture, the net output of the power plant would be 400MW. Feedstock utilisation would be around 1.05Mt/year based on an annual load factor for the gasification plant of 87.5%. The plant would be economically viable providing carbon credits of 20 Euros per tonne of CO 2 avoided were available, e.g. from the European Union (EU) Emission Trading Scheme (ETS). This is approximately the current price of EU ETS credits at the time of writing. The CO 2 would be captured pre-combustion, using a physical solvent process. The pipeline would be constructed of carbon steel and would consist of an onshore leg of around 90km and an offshore leg of around 45km. Pipeline capital costs are assessed at between 50-70MEuros. Annual pipeline operation and maintenance costs are assessed as 3% of the capital cost, at around 1.8MEuros. Geological investigations demonstrated that the opportunities for geological storage of CO 2 in the Welsh coalfield and the Bristol Channel are limited, and the best potential for a geological CO 2 storage site for the CO 2 captured from the Valleys power plant is in the St George's Channel Basin (SGCB), off the NW coast of Pembrokeshire. An outline risk assessment of CO 2 storage at this site was undertaken. The reservoir consists of relatively thin fluvial sands that occur near the base of the Cainozoic succession. The distribution of these sands in 3

  15. Aluminophosphate monoliths with high CO2-over-N2 selectivity and CO2 capture capacity

    OpenAIRE

    Akhtar, Farid; Keshavarzi, Neda; Shakarova, Dilshod; Cheung, Ocean; Hedin, Niklas; Bergström, Lennart

    2014-01-01

    Monoliths of microporous aluminophosphates (AlPO4-17 and AlPO4-53) were structured by binder-freepulsed current processing. Such monoliths could be important for carbon capture from flue gas. TheAlPO4-17 and AlPO4-53 monoliths exhibited a tensile strength of 1.0 MPa and a CO2 adsorption capacityof 2.5 mmol g1 and 1.6 mmol g1, respectively at 101 kPa and 0 C. Analyses of single component CO2and N2 adsorption data indicated that the AlPO4-53 monoliths had an extraordinarily high CO2-over-N2sele...

  16. Reducing CO2 from shipping – do non-CO2 effects matter?

    Directory of Open Access Journals (Sweden)

    M. S. Eide

    2013-04-01

    Full Text Available Shipping is a growing sector in the global economy, and it contributions to global CO2 emissions are expected to increase. CO2 emissions from the world shipping fleet will likely be regulated in the near future, and studies have shown that significant emission reductions can be achieved at low cost. Regulations are being discussed for both existing ships as well as for future additions to the fleet. In this study a plausible CO2 emission reduction inventory is constructed for the cargo fleet existing in 2010, as well as for container ships, bulk ships and tankers separately. In the reduction inventories, CO2 emissions are reduced by 25–32% relative to baseline by applying 15 technical and operational emission reduction measures in accordance with a ship-type-specific cost-effectiveness criterion, and 9 other emission compounds are changed as a technical implication of reducing CO2. The overall climate and environmental effects of the changes to all 10 emission components in the reduction inventory are assessed using a chemical transport model, radiative forcing (RF models and a simple climate model. We find substantial environmental and health benefits with up to 5% reduction in surface ozone levels, 15% reductions in surface sulfate and 10% reductions in wet deposition of sulfate in certain regions exposed to heavy ship traffic. The major ship types show distinctly different contributions in specific locations. For instance, the container fleet contributes 50% of the sulfate decline on the west coast of North America. The global radiative forcing from a 1 yr emission equal to the difference between baseline and reduction inventory shows an initial strong positive forcing from non-CO2 compounds. This warming effect is due to reduced cooling by aerosols and methane. After approximately 25 yr, the non-CO2 forcing is balanced by the CO2 forcing. For the global mean temperature change, we find a shift from warming to cooling after approximately 60

  17. Synthesis and characterization of mesoporous materials for CO2 capture: influence of nickel oxide

    International Nuclear Information System (INIS)

    Nascimento, Alexsandra Rodrigues do

    2014-01-01

    Several materials are currently under study for the CO 2 capture process, like the metal oxides and mixed metal oxides, zeolites, carbonaceous materials, metal-organic frameworks (MOF's) organosilica and modified silica surfaces. In this work, evaluated the adsorption capacity of CO 2 in mesoporous materials of different structures, such as MCM-48 and SBA-15 without impregnating and impregnated with nickel in the proportions 5 %, 10 % and 20 % (m/m), known as 5Ni-MCM-48, 10Ni-MCM-48, 20Ni-MCM-48 and 5Ni-SBA-15, 10Ni-SBA-15, 20Ni-SBA-15. The materials were characterized by means of X-ray diffraction (XRD), thermal analysis (TG and DTG), Fourier transform infrared spectroscopy (FT-IR), N 2 adsorption and desorption (BET) and scanning electron microscopy (SEM) with EDS. The adsorption process was performed varying the pressure of 100 - 4000 kPa and keeping the temperature constant and equal to 298 K. At a pressure of 100 kPa, higher concentrations of adsorption occurred for the materials 5Ni-MCM-48 (0.795 mmol g -1 ) and SBA-15 (0.914 mmol g -1 ) is not impregnated, and at a pressure of 4000 kPa for MCM-48 materials (14.89 mmol g -1 ) and SBA-15 (9.97 mmol g -1 ) not impregnated. The results showed that the adsorption capacity varies positively with the specific area, however, has a direct dependency on the type and geometry of the porous structure of channels. The data were fitted using the Langmuir and Freundlich models and were evaluated thermodynamic parameters Gibbs free energy and entropy of the adsorption system. (author)

  18. Response of atmospheric CO2 to changes in land use

    International Nuclear Information System (INIS)

    King, A.W.; Emanuel, W.R.; Post, W.M.

    1991-01-01

    This chapter examines how different histories of CO 2 release from past changes in land use influence the simulation of past and future changes in atmospheric CO 2 . The authors first simulate past change in atmospheric CO 2 using reconstructed histories of land-use CO 2 release from a historical-ecological model of land-use change and CO 2 release. They examine the impact of each history on the coincidence between simulated and observed atmospheric CO 2 . They then compare these CO 2 release histories, and their contribution to coincidence or noncoincidence of simulation and observation, with histories reconstructed by deconvolution of the atmospheric CO 2 record. They conclude by exploring the implications of these deconvolved reconstructions for the simulation of future changes in atmospheric CO 2

  19. CO2 Emissions from Fuel Combustion 2011: Highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    How much CO2 are countries emitting? Where is it coming from? In the lead-up to the UN climate negotiations in Durban, the latest information on the level and growth of CO2 emissions, their source and geographic distribution will be essential to lay the foundation for a global agreement. To provide input to and support for the UN process the IEA is making available for free download the 'Highlights' version of CO2 Emissions from Fuel Combustion. This annual publication contains: - estimates of CO2 emissions by country from 1971 to 2009; - selected indicators such as CO2/GDP, CO2/capita, CO2/TPES and CO2/kWh; - CO2 emissions from international marine and aviation bunkers, and other relevant information. These estimates have been calculated using the IEA energy databases and the default methods and emission factors from the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories.

  20. CO(2) Inhibits Respiration in Leaves of Rumex crispus L.

    Science.gov (United States)

    Amthor, J S; Koch, G W; Bloom, A J

    1992-02-01

    Curly dock (Rumex crispus L.) was grown from seed in a glasshouse at an ambient CO(2) partial pressure of about 35 pascals. Apparent respiration rate (CO(2) efflux in the dark) of expanded leaves was then measured at ambient CO(2) partial pressure of 5 to 95 pascals. Calculated intercellular CO(2) partial pressure was proportional to ambient CO(2) partial pressure in these short-term experiments. The CO(2) level strongly affected apparent respiration rate: a doubling of the partial pressure of CO(2) typically inhibited respiration by 25 to 30%, whereas a decrease in CO(2) elicited a corresponding increase in respiration. These responses were readily reversible. A flexible, sensitive regulatory interaction between CO(2) (a byproduct of respiration) and some component(s) of heterotrophic metabolism is indicated.

  1. CO2 Emissions from Fuel Combustion - 2012 Highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    How much CO2 are countries emitting? Where is it coming from? In the lead-up to the UN climate negotiations in Doha, the latest information on the level and growth of CO2 emissions, their source and geographic distribution will be essential to lay the foundation for a global agreement. To provide input to and support for the UN process the IEA is making available for free download the 'Highlights' version of CO2 Emissions from Fuel Combustion. This annual publication contains: estimates of CO2 emissions by country from 1971 to 2010; selected indicators such as CO2/GDP, CO2/capita, CO2/TPES and CO2/kWh; and CO2 emissions from international marine and aviation bunkers, and other relevant information.

  2. CO2 point sources and subsurface storage capacities for CO2 in aquifers in Norway

    International Nuclear Information System (INIS)

    Boee, Reidulv; Magnus, Christian; Osmundsen, Per Terje; Rindstad, Bjoern Ivar

    2002-01-01

    The GESTCO project comprises a study of the distribution and coincidence of thermal CO 2 emission sources and location/quality of geological storage capacity in Europe. Four of the most promising types of geological storage are being studied. 1. Onshore/offshore saline aquifers with or without lateral seal. 2. Low entalpy geothermal reservoirs. 3. Deep methane-bearing coal beds and abandoned coal and salt mines. 4. Exhausted or near exhausted hydrocarbon structures. In this report we present an inventory of CO 2 point sources in Norway (1999) and the results of the work within Study Area C: Deep saline aquifers offshore/near shore Northern and Central Norway. Also offshore/near shore Southern Norway has been included while the Barents Sea is not described in any detail. The most detailed studies are on the Tilje and Aare Formations on the Troendelag Platform off Mid-Norway and on the Sognefjord, Fensfjord and Krossfjord Formations, southeast of the Troll Field off Western Norway. The Tilje Formation has been chosen as one of the cases to be studied in greater detail (numerical modelling) in the project. This report shows that offshore Norway, there are concentrations of large CO 2 point sources in the Haltenbanken, the Viking Graben/Tampen Spur area, the Southern Viking Graben and the central Trough, while onshore Norway there are concentrations of point sources in the Oslofjord/Porsgrund area, along the coast of western Norway and in the Troendelag. A number of aquifers with large theoretical CO 2 storage potential are pointed out in the North Sea, the Norwegian Sea and in the Southern Barents Sea. The storage capacity in the depth interval 0.8 - 4 km below sea level is estimated to be ca. 13 Gt (13000000000 tonnes) CO 2 in geological traps (outside hydrocarbon fields), while the storage capacity in aquifers not confined to traps is estimated to be at least 280 Gt CO 2 . (Author)

  3. Interface characteristics in Co2MnSi/Ag/Co2MnSi trilayer

    Science.gov (United States)

    Li, Yang; Chen, Hong; Wang, Guangzhao; Yuan, Hongkuan

    2016-05-01

    Interface characteristics of Co2MnSi/Ag/Co2MnSi trilayer have been investigated by means of first-principles. The most likely interface is formed by connecting MnSi-termination to the bridge site between two Ag atoms. As annealed at high temperature, the formation of interface DO3 disorder is most energetically favorable. The spin polarization is reduced by both the interface itself and interface disorder due to the interface state occurs in the minority-spin gap. As a result, the magneto-resistance ratio has a sharp drop based on the estimation of a simplified modeling.

  4. Influence of the cation substitution on the magnetic properties of LiCo2O4 and Li(Me,Co2O4 spinels

    Directory of Open Access Journals (Sweden)

    Gautier, J. L.

    2004-08-01

    Full Text Available Lithium-based cells LiCo2O4 have been characterized by magnetic techniques, looking at the influence of the partial substitution of cobalt by 3d or 4d transition metal elements (Fe, Ni, Cu, Cr, Mo. The non-substituted compound LiCo2O4 behaves as an antiferromagnet, with a Néel temperature TN of 30 K, although antiferromagnetic interactions are much more important, as suggested by a Weiss parameter Θ of the order of ‑225 K. In the solid solution Li(NixCo2‑xO4 the Weiss parameter Θ changes with x(Ni, reaching large positive values (e.g., Θ ~ +230 K, for x = 0.5. This phenomenon suggests the existence of a canted‑antiferromagnetic or ferrimagnetic structures with large ferromagnetic components. Substitution of cobalt by other 3d or 4d transition metals in the LiMe0.5Co1.5O4 series shows dramatic effects with respect to the non-substituted LiCo2O4 compound : copper completely suppresses the magnetic order, while iron increases TN to almost room temperature. No modifications are observed when molybdenum substitutes cobalt, while chromium transforms the AF order in a ferromagnetic one, with Tc of about 90 K.Se ha caracterizado por técnicas magnéticas, el efecto de la sustitución parcial de Co por elementos de transición 3d o 4d (Fe, Ni, Cu, Cr, Mo en celdas LiCo2O4 a base de litio. El compuesto no sustituído LiCo2O4, se comporta como un antiferromagneto de temperatura de Néel TN de 30 K, aunque existen interacciones antiferromagnéticas mucho más importantes, como lo indica un parámetro de Weiss Θ del orden de -225K. En la solución sólida Li(NixCo2‑xO4, el parámetro de Weiss Θ cambia con x(Ni, alcanzando valores positivos altos (e.g., Θ ~ +230K, para x=0.5. Este fenómeno sugiere la existencia de una estructura antiferromagnética inclinada (“AF-canted” o de una estructura ferrimagnética, donde predominan componentes ferromagnéticas importantes. La sustitución del cobalto por otros elementos de transición 3d o 4d en

  5. Power stabilized CO2 gas transport laser

    International Nuclear Information System (INIS)

    Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

    1975-01-01

    The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

  6. Enhanced Molecular Sieve CO2 Removal Evaluation

    Science.gov (United States)

    Rose, Susan; ElSherif, Dina; MacKnight, Allen

    1996-01-01

    The objective of this research is to quantitatively characterize the performance of two major types of molecular sieves for two-bed regenerative carbon dioxide removal at the conditions compatible with both a spacesuit and station application. One sorbent is a zeolite-based molecular sieve that has been substantially improved over the materials used in Skylab. The second sorbent is a recently developed carbon-based molecular sieve. Both molecular sieves offer the potential of high payoff for future manned missions by reducing system complexity, weight (including consumables), and power consumption in comparison with competing concepts. The research reported here provides the technical data required to improve CO2 removal systems for regenerative life support systems for future IVA and EVA missions.

  7. High gain, multiatmosphere CO2 laser amplifier

    Science.gov (United States)

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

    1987-02-01

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

  8. Smart Transportation CO2 Emission Reduction Strategies

    Science.gov (United States)

    Tarulescu, S.; Tarulescu, R.; Soica, A.; Leahu, C. I.

    2017-10-01

    Transport represents the sector with the fastest growing greenhouse gas emissions around the world. The main global objective is to reduce energy usage and associated greenhouse gas emissions from the transportation sector. For this study it was analyzed the road transportation system from Brasov Metropolitan area. The study was made for the transportation route that connects Ghimbav city to the main surrounding objectives. In this study ware considered four optimization measures: vehicle fleet renewal; building the detour belt for the city; road increasing the average travel speed; making bicycle lanes; and implementing an urban public transport system for Ghimbav. For each measure it was used a mathematical model to calculate the energy consumption and carbon emissions from the road transportation sector. After all four measures was analyzed is calculated the general energy consumption and CO2 reduction if this are applied from year 2017 to 2020.

  9. Tritium removal by CO2 laser heating

    International Nuclear Information System (INIS)

    Skinner, C.H.; Kugel, H.; Mueller, D.

    1997-01-01

    Efficient techniques for rapid tritium removal will be necessary for ITER to meet its physics and engineering goals. One potential technique is transient surface heating by a scanning CO 2 or Nd:Yag laser that would release tritium without the severe engineering difficulties of bulk heating of the vessel. The authors have modeled the heat propagation into a surface layer and find that a multi-kW/cm 2 flux with an exposure time of order 10 ms is suitable to heat a 50 micron co-deposited layer to 1,000--2,000 degrees. Improved wall conditioning may be a significant side benefit. They identify remaining issues that need to be addressed experimentally

  10. Tritium removal by CO2 laser heating

    International Nuclear Information System (INIS)

    Skinner, C.H.; Kugel, H.; Mueller, D.

    1997-10-01

    Efficient techniques for rapid tritium removal will be necessary for ITER (International Thermonuclear Experimental Reactor) to meet its physics and engineering goals. One potential technique is transient surface heating by a scanning CO 2 or Nd:YAG laser that would release tritium without the severe engineering difficulties of bulk heating of the vessel. The authors have modeled the heat propagation into a surface layer and find that a multi-kW/cm 2 flux with an exposure time of order 10 msec is suitable to heat a 50 micron co-deposited layer to 1,000--2,000 degrees. Improved wall conditioning may be a significant side benefit. They identify remaining issues that need to be addressed experimentally

  11. Goodbye water use, tailings and Co2?

    Energy Technology Data Exchange (ETDEWEB)

    Stastny, R.P.

    2011-03-15

    Alberta Bitumen Link (ABL), a new integrated oilsands technology, is described. ABL combines the use of dimethyl ester (DME) as a solvent at lower temperatures in SAGD and the manufacture of DME by gasification of coal and asphaltenes so CO2 formation is reduced. The heat from the gasification process cogenerates electricity, while the produced DME is sent for use in the in-situ bitumen recovery. ABL finds the same mobility in bitumen stimulated with solvent at 80 C as a reservoir heated to 230 C by steam. The intellectual property now resides with Envirotech Consulting Inc. of Edmonton and Thermax Systems Co. of Japan and the technology is in small-scale testing. 1 fig.

  12. Experimental Investigations into CO2 Interactions with Injection Well Infrastructure for CO2 Storage

    Science.gov (United States)

    Syed, Amer; Shi, Ji-Quan; Durucan, Sevket; Nash, Graham; Korre, Anna

    2013-04-01

    Wellbore integrity is an essential requirement to ensure the success of a CO2 Storage project as leakage of CO2 from the injection or any other abandoned well in the storage complex, could not only severely impede the efficiency of CO2 injection and storage but also may result in potential adverse impact on the surrounding environment. Early research has revealed that in case of improper well completions and/or significant changes in operating bottomhole pressure and temperature could lead to the creation of microannulus at cement-casing interface which may constitute a preferential pathway for potential CO2 leakage during and post injection period. As a part of a European Commission funded CO2CARE project, the current research investigates the sealing behaviour of such microannulus at the cement-casing interface under simulated subsurface reservoir pressure and temperature conditions and uses the findings to develop a methodology to assess the overall integrity of CO2 storage. A full scale wellbore experimental test set up was constructed for use under elevated pressure and temperature conditions as encountered in typical CO2 storage sites. The wellbore cell consists of an assembly of concentric elements of full scale casing (Diameter= 0.1524m), cement sheath and an outer casing. The stainless steel outer ring is intended to simulate the stiffness offered by the reservoir rock to the displacement applied at the wellbore. The Central Loading Mechanism (CLM) consists of four case hardened shoes that can impart radial load onto the well casing. The radial movement of the shoes is powered through the synchronised movement of four precision jacks controlled hydraulically which could impart radial pressures up to 15 MPa. The cell body is a gas tight enclosure that houses the wellbore and the central loading mechanism. The setup is enclosed in a laboratory oven which acts both as temperature and safety enclosure. Prior to a test, cement mix is set between the casing and

  13. CO2 laser milling of hard tissue

    Science.gov (United States)

    Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

    2007-02-01

    Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 μm) with pulse duration of 50 - 100 μs, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

  14. CO2 chemoreception in cardiorespiratory control.

    Science.gov (United States)

    Putnam, Robert W

    2010-06-01

    Considerable progress has been made elucidating the cellular signals and ion channel targets involved in the response to increased CO2/H+ of brain stem neurons from chemosensitive regions. Intracellular pH (pHi) does not exhibit recovery from an acid load when extracellular pH (pHo) is also acid. This lack of pHi recovery is an essential but not unique feature of all chemosensitive neurons. These neurons have pH-regulating transporters, especially Na+/H+ exchangers, but some may also contain HCO3--dependent transporters as well. Studies in locus ceruleus (LC) neurons have shown that firing rate will increase in response to decreased pHi or pHo but not in response to increased CO2 alone. A number of K+ channels, as well as other channels, have been suggested to be targets of these pH changes with a fall of pH inhibiting these channels. In neurons from some regions it appears that multiple signals and multiple channels are involved in their chemosensitive response while in neurons from other regions a single signal and/or channel may be involved. Despite the progress, a number of key issues remain to be studied. A detailed study of chemosensitive signaling needs to be done in neurons from more brain stem regions. Fully describing the chemosensitive signaling pathways in brain stem neurons will offer new targets for therapies to alter the strength of central chemosensitivity and will yield new insights into the reason why there are multiple central chemoreceptive sites.

  15. Test results on vegetable cultivation using fish breeding water; Yogyosui riyo ni yoru yasai saibai shikenkekka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, S. [Hokuriku Electric Power Co. Inc., Toyama (Japan)

    1997-10-30

    Although a part of the entrails of fishes, birds and livestock is used for food, most of them are treated by costly combustion because of their bad odor and looking, and International Environment and Welfare Laboratory, Toyama prefecture in Japan is studying their profitable treatment. As a part of such study, possibility of hydroponic cultivation of vegetable was tested using fish breeding water including excretions of fishes and residual feeds after use of waste as feed, and the growth condition, safety and effectiveness of cultured vegetable were verified. Three-hundred and fifty viviparous Oryzias were released into a breeding water area with no controlled pH and EC (electric conductivity). For comparison a culture solution area of 6.0 in pH and 1.2ms/cm in EC was prepared. The result on cultivation of 6 kinds of vegetable in culture beds supported by circulation of these water showed that hydroponic cultivation of vegetable using fish breeding water is possible, and average growth of 68% is obtained although difference in growth for every vegetable is found. 8 figs., 5 tabs.

  16. Test results of cultivation of vegetables with fish breeding water; Yogyosui riyo ni yoru yasai saibai shiken kekka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, S. [Hokuriku Electric Power Co. Inc., Toyama (Japan)

    1997-10-28

    Entrails of fish, fowls and domestic animals are mostly incinerated at large expenses, although partly used as foods. This study is to test `possibility of vegetable cultivation with fish breeding water,` where the entrail wastes are used as baits for fish breeding, and fish excretions are used as the fertilizer for vegetable cultivation to purify water for fish breeding. The cultivation bed consists of two sections, one for fish breeding/vegetable cultivation and the other for vegetable cultivation by the normal method. Vegetable grow notably less in the former than in the latter, 54.6 to 79.5 versus 100. Spinach contains slightly higher contents of vitamins A and C by 6 and 13%, when cultivated in the former than in the latter. Quantities of total nitrogen, phosphorus and potassium as the fertilizer components in the former are 49, 49 and 1.7% of those in the latter. It is predicted, judging from growth of the vegetables, that the former gives a harvest comparable with that by the latter, when given a 6 to 13 days longer cultivation period. 3 figs., 2 tabs.

  17. Research on environmental bioecosensing technology using ecological information; Seitaikei joho ni yoru kankyo bio eco sensing gijutsu ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The bioecosensing technology was studied which detects and identifies feeble signals generated by biosystem communication in wide biological environment. The following were reported as current notable environmental biosensing technologies: a quick measurement method of environmental contaminants using immunological measurement method, analysis method of ecological state of microorganism using DNA probes, observation of ecosystem by bioluminescent system, measurement method of environmental changes and contaminants using higher animals and plants, and detection method of chemical contaminants using chemotaxis of microorganism. As a result, the new bioecosensing/monitoring technology in molecular level was suggested for identifying comprehensive environmental changes which could not be measured by previous physical and chemical methods, as changes in ecosystem corresponding to environmental changes. As the wide area remote sensing technology of environmental ecological information, sensing technology on the earth, aircraft and satellite was also discussed. 247 refs., 55 figs., 17 tabs.

  18. Flat plate approximation in the three-dimensional slamming; Heiban kinji ni yoru sanjigen suimen shogeki keisanho ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, Y. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

    1996-12-31

    A slamming load generated by interactive motions between a ship body and water face is an important load in ensuring safety of the ship. A flat plate approximation developed by Wagner is used as a two-dimensional slamming theory, but it has a drawback in handling edges of a flat plate. Therefore, an attempt was made to expand the two-dimensional Wagner`s theory to three dimensions. This paper first shows a method to calculate water face slamming of an arbitrary axisymmetric body by using circular plate approximation. The paper then proposes a method to calculate slamming pressure distribution and slamming force for the case when shape of the water contacting surface may be approximated by an elliptic shape. Expansion to the three dimensions made clear to some extent the characteristics of the three-dimensional slamming. In the case of two dimensions or a circular column for example, the water contacting area increases rapidly in the initial stage generating large slamming force. However, in the case of three dimensions, since the water contacting area expands longitudinally and laterally, the slamming force tends to increase gradually. Maximum slamming pressure was found proportional to square of moving velocity in a water contacting boundary in the case of three dimensions, and similar to stagnation pressure on a gliding plate. 12 refs., 17 figs., 1 tab.

  19. Research on crystal growth by using pressure as a control parameter; Atsuryoku seigyo ni yoru kessho seicho ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-31

    This research project aims to establish a technique for crystal growth using pressure as a principal control parameter, and combining it with a microgravity condition, to develop a novel process material fabrication. Since the solubility of materials depends on pressure, it is possible to control a supersaturated condition for crystal growth by changing pressure. The growth condition can be controlled precisely, which is not possible by conventional methods that vary temperature and other factors. On the other hand, because a concentration diffusing field is formed autonomically around crystals in association with their growth, density convection is generated under gravity as a result of difference in the concentrations, making the growth conditions severely complex and uncontrollable. Ideal crystal growth condition control may be possible if the pressure control is performed under micro-gravity by which generation of the density convection can be suppressed. Realization has been achieved on in-situ observation by using high-magnification microscope which uses a diamond anvil cell, development of a hydraulic type optic pressure cell, and a high- speed crystal growing technology by means of pressure control utilizing the cell. New findings were also obtained on effects of pressure on crystal forms, and the pressure induced solid phase transfer mechanism. 67 refs., 49 figs., 3 tabs.

  20. Consideration on local blast vibration control by delay blasting; Danpatsu happa ni yoru kyokuchiteki shindo seigyo ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Mogi, Gento; Adachi, Tsuyoshi; Yamatomi, Jiro [The University of Tokyo School of Engineering Department of Geosystem Engineering, Tokyo (Japan); Hoshino, Tatsuya [Mitsui Mining and Smelting Corp., Tokyo (Japan)

    1999-10-31

    In this research, local blast vibration control based on the theory of superposition of waves was investigated. Firstly, the influence of delay time errors of conventional electric detonators upon the level of local blast vibration was examined. Secondly, for a further effective local blast vibration control, a new delay blasting design concept 'combined delay blasting' that postulates the use of electronic detonators, which virtually have no delay time errors, is proposed. For a delay blasting with uniform detonation time intervals, an optimum time interval to minimize the local PPV (Peak Particle Velocity) is obtained based on the relationship between the PPV and the time interval, which is derived by superposing identical vibration time histories of each single hole shot. However, due to the scattering of the actual delay time caused by errors, PPV of a production blast seldom coincides with the estimated one. Since the expected value and the variance of PPV mainly depend on sensitivity of PPV around the nominal delay time, it is proposed that not only the optimum but also several sub-optimum candidates of delay time should be examined taking error into consideration. Concerning the 'combined delay blasting', its concept and some simulation results are presented. The estimated reduction effect of blast vibration of a delay blast based on this concept was quite favorable, indicating a possibility for further effective local blast vibration control. (author)

  1. Faults as Windows to Monitor Gas Seepage: Application to CO2 Sequestration and CO2-EOR

    Directory of Open Access Journals (Sweden)

    Ronald W. Klusman

    2018-03-01

    Full Text Available Monitoring of potential gas seepage for CO2 sequestration and CO2-EOR (Enhanced Oil Recovery in geologic storage will involve geophysical and geochemical measurements of parameters at depth and at, or near the surface. The appropriate methods for MVA (Monitoring, Verification, Accounting are needed for both cost and technical effectiveness. This work provides an overview of some of the geochemical methods that have been demonstrated to be effective for an existing CO2-EOR (Rangely, CA, USA and a proposed project at Teapot Dome, WY, USA. Carbon dioxide and CH4 fluxes and shallow soil gas concentrations were measured, followed by nested completions of 10-m deep holes to obtain concentration gradients. The focus at Teapot Dome was the evaluation of faults as pathways for gas seepage in an under-pressured reservoir system. The measurements were supplemented by stable carbon and oxygen isotopic measurements, carbon-14, and limited use of inert gases. The work clearly demonstrates the superiority of CH4 over measurements of CO2 in early detection and quantification of gas seepage. Stable carbon isotopes, carbon-14, and inert gas measurements add to the verification of the deep source. A preliminary accounting at Rangely confirms the importance of CH4 measurements in the MVA application.

  2. Root-derived CO2 efflux via xylem stream rivals soil CO2 efflux

    Science.gov (United States)

    Doug P. Aubrey; Robert O. Teskey

    2009-01-01

    Respiration consumes a large portion of annual gross primary productivity in forest ecosystems and is dominated by belowground metabolism. Here, we present evidence of a previously unaccounted for internal CO2 flux of large magnitude from tree roots through stems. If this pattern is shown to persist over time and in other forests, it suggests...

  3. Enhanced transport phenomena in CO2 sequestration and CO2 EOR

    NARCIS (Netherlands)

    Farajzadeh, R.

    2009-01-01

    The results of this thesis give insight into the (mass)-transfer during flow of gases, especially CO2, in various gas-liquid systems. A number of experiments was performed to investigate the transport phenomena through interfaces with and without surfactant monolayers. The observed phenomena have

  4. CO2-ECBM and CO2 Sequestration in Polish Coal Seam – Experimental Study

    Directory of Open Access Journals (Sweden)

    Paweł Baran

    2014-01-01

    Originality/value: The results indicate successful sorption of carbon dioxide in each experiment. This provides the rationale to study the application of the coal tested to obtain methane genetic origin genetic methane with the use of the CO2 injection.

  5. Interface characteristics in Co2MnSi/Ag/Co2MnSi trilayer

    International Nuclear Information System (INIS)

    Li, Yang; Chen, Hong; Wang, Guangzhao; Yuan, Hongkuan

    2016-01-01

    Highlights: • Inferface DO 3 disorder is most favorable in Co 2 MnSi/Ag/Co 2 MnSi trilayer. • Interface itself and inferface DO 3 disorder destroy the half-metallicity of interface layers. • Magnetoresistance is reduced by the interface itself and interface disorder. • Magnetotransport coefficient is largely reduced by the interface itself and interface disorder. - Abstract: Interface characteristics of Co 2 MnSi/Ag/Co 2 MnSi trilayer have been investigated by means of first-principles. The most likely interface is formed by connecting MnSi-termination to the bridge site between two Ag atoms. As annealed at high temperature, the formation of interface DO 3 disorder is most energetically favorable. The spin polarization is reduced by both the interface itself and interface disorder due to the interface state occurs in the minority-spin gap. As a result, the magneto-resistance ratio has a sharp drop based on the estimation of a simplified modeling.

  6. Decontamination of solid matrices using supercritical CO2: study of contaminant-additives-CO2

    International Nuclear Information System (INIS)

    Galy, J.

    2006-11-01

    This work deals with the decontamination of solid matrices by supercritical CO 2 and more particularly with the study of the interactions between the surfactants and the CO 2 in one part, and with the interactions between the contaminant and the surfactants in another part. The first part of this study has revealed the different interactions between the Pluronics molecules and the supercritical CO 2 . The diagrams graphs have shown that the pluronics (PE 6100, PE 8100 and PE 10100) present a solubility in the supercritical CO 2 low but sufficient (0.1% m/m at 25 MPa and 313 K) for the studied application: the treatment of weak quantities of cerium oxide (or plutonium). An empirical approach based on the evolutions of the slops value and of the origin ordinates of the PT diagrams has been carried out to simulate the phase diagrams PT of the Pluronics. A modeling based on the state equations 'SAFT' (Statistical Associating Fluid Theory) has been studied in order to confirm the experimental results of the disorder points and to understand the role of the different blocks 'PEO' and 'PPO' in the behaviour of Pluronics; this modeling confirms the evolution of the slopes value with the 'CO 2 -phily' of the system. The measure of the surface tension in terms of the Pluronics concentration (PE 6100, 81000 and 10100) has shown different behaviours. For the PE 6100, the surface tension decreases when the surfactant concentration increases (at constant pressure and temperature); on the other hand, for the PE 8100 a slop rupture appears and corresponds to the saturation of the interface water/CO 2 and allows then to determine the Interface Saturation Concentration (ISC). The ISC value (at constant pressure and temperature) increases with an increase of the 'CO 2 -phily'). The model hydrophilous medium being an approximation, it has been replaced by a solid polar phase of CeO 2 . A parallel has been established between the evolution of the surface tension between the water and

  7. High-resolution global CO2 modeling: a comparison to GOSAT column CO2 retrievals

    Science.gov (United States)

    Baker, D. F.

    2010-12-01

    Over a year’s worth of column CO2 concentrations retrieved by the Japanese Greenhouse-gases Observing Satellite (GOSAT) are now available: with a global distribution and good sensitivity down to the surface, these data could provide an important new view of the functioning of the global carbon cycle. The retrievals seem to be corrupted by systematic errors with a magnitude of several ppm, however; to be truly useful, these biases must be greatly reduced before being used in atmospheric transport inversions. Here GOSAT column CO2 retrievals are compared to values from a high-resolution global atmospheric transport model; the residuals are correlated with a variety of factors (including aerosol optical depth, cloud coverage, surface type, and viewing geometry) globally, across a full year of data, to help identify systematic errors in the retrievals and attribute them to possible causes. This broad comparison to model data is meant to complement the comparison to in situ CO2 measurements and upward-looking Fourier spectrometer data currently being used to validate the retrievals at a relatively few times and locations. NASA’s GEOS5 analyzed meteorology products at 0.5° x 0.67° resolution (lat/lon) are used both to compute diurnally-varying land biospheric fluxes (with the SiB model) and to transport these fluxes through the atmosphere with the off-line PCTM model (40 vertical layers, also at 0.5° x 0.67°). Global fossil fuel fluxes with similarly-high spatial resolution, but low temporal resolution, plus monthly varying air-sea fluxes from an ocean model, are also transported. The net fluxes and CO2 fields are optimized at coarse scales in a Transcom-like time-dependent inversion to agree with data from the in situ CO2 measurement network before the GOSAT comparison is made.

  8. Novel Long-Term CO2 Removal System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Current Technology for CO2 removal from enclosed air of spacecraft utilizes LiOH canisters for CO2 absorption. This absorption is irreversible so longer flights...

  9. Non-CO2 Greenhouse Gases: International Emissions and Projections

    Science.gov (United States)

    EPA August 2011 report on global non-CO2 emissions projections (1990-2030) for emissions of non-CO2 greenhouse gases (methane, nitrous oxide, and fluorinated greenhouse gases) from more than twenty emissions sources.

  10. Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

    Science.gov (United States)

    This revision of the 2011 report, Accounting Framework for Biogenic CO2 Emissions from Stationary Sources, evaluates biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with assessing biogenic carbon dioxide...

  11. Understanding activity and selectivity of metal-nitrogen-doped carbon catalysts for electrochemical reduction of CO2.

    Science.gov (United States)

    Ju, Wen; Bagger, Alexander; Hao, Guang-Ping; Varela, Ana Sofia; Sinev, Ilya; Bon, Volodymyr; Roldan Cuenya, Beatriz; Kaskel, Stefan; Rossmeisl, Jan; Strasser, Peter

    2017-10-16

    Direct electrochemical reduction of CO 2 to fuels and chemicals using renewable electricity has attracted significant attention partly due to the fundamental challenges related to reactivity and selectivity, and partly due to its importance for industrial CO 2 -consuming gas diffusion cathodes. Here, we present advances in the understanding of trends in the CO 2 to CO electrocatalysis of metal- and nitrogen-doped porous carbons containing catalytically active M-N x moieties (M = Mn, Fe, Co, Ni, Cu). We investigate their intrinsic catalytic reactivity, CO turnover frequencies, CO faradaic efficiencies and demonstrate that Fe-N-C and especially Ni-N-C catalysts rival Au- and Ag-based catalysts. We model the catalytically active M-N x moieties using density functional theory and correlate the theoretical binding energies with the experiments to give reactivity-selectivity descriptors. This gives an atomic-scale mechanistic understanding of potential-dependent CO and hydrocarbon selectivity from the M-N x moieties and it provides predictive guidelines for the rational design of selective carbon-based CO 2 reduction catalysts.Inexpensive and selective electrocatalysts for CO 2 reduction hold promise for sustainable fuel production. Here, the authors report N-coordinated, non-noble metal-doped porous carbons as efficient and selective electrocatalysts for CO 2 to CO conversion.

  12. CO2 perturbation in aquifers : reaction kinetics and metals behavior

    OpenAIRE

    Rillard, Jean

    2013-01-01

    The aim of this thesis was to investigate hydrogeochemical perturbation induced by CO2 in natural aquifers. In a first step, we used chemical data from natural CO2-rich hydrothermal water. We studied variation of fluid chemical composition as a function of CO2 content in order to evaluate reactivity of minerals composing the initial reservoir. Fluid chemical analyses showed decrease in pH, and systematic enrichment in alkalinity and major cations correlated to increase in CO2 content. Chemica...

  13. Can elevated CO(2) improve salt tolerance in olive trees?

    Science.gov (United States)

    Melgar, Juan Carlos; Syvertsen, James P; García-Sánchez, Francisco

    2008-04-18

    We compared growth, leaf gas exchange characteristics, water relations, chlorophyll fluorescence, and Na(+) and Cl(-) concentration of two cultivars ('Koroneiki' and 'Picual') of olive (Olea europaea L.) trees in response to high salinity (NaCl 100mM) and elevated CO(2) (eCO(2)) concentration (700microLL(-1)). The cultivar 'Koroneiki' is considered to be more salt sensitive than the relatively salt-tolerant 'Picual'. After 3 months of treatment, the 9-month-old cuttings of 'Koroneiki' had significantly greater shoot growth, and net CO(2) assimilation (A(CO(2))) at eCO(2) than at ambient CO(2), but this difference disappeared under salt stress. Growth and A(CO(2)) of 'Picual' did not respond to eCO(2) regardless of salinity treatment. Stomatal conductance (g(s)) and leaf transpiration were decreased at eCO(2) such that leaf water use efficiency (WUE) increased in both cultivars regardless of saline treatment. Salt stress increased leaf Na(+) and Cl(-) concentration, reduced growth and leaf osmotic potential, but increased leaf turgor compared with non-salinized control plants of both cultivars. Salinity decreased A(CO(2)), g(s), and WUE, but internal CO(2) concentrations in the mesophyll were not affected. eCO(2) increased the sensitivity of PSII and chlorophyll concentration to salinity. eCO(2) did not affect leaf or root Na(+) or Cl(-) concentrations in salt-tolerant 'Picual', but eCO(2) decreased leaf and root Na(+) concentration and root Cl(-) concentration in the more salt-sensitive 'Koroneiki'. Na(+) and Cl(-) accumulation was associated with the lower water use in 'Koroneiki' but not in 'Picual'. Although eCO(2) increased WUE in salinized leaves and decreased salt ion uptake in the relatively salt-tolerant 'Koroneiki', growth of these young olive trees was not affected by eCO(2).

  14. [Effects of plastic film mulching on soil CO2 efflux and CO2 concentration in an oasis cotton field].

    Science.gov (United States)

    Yu, Yong-xiang; Zhao, Cheng-yi; Jia, Hong-tao; Yu, Bo; Zhou, Tian-he; Yang, Yu-guang; Zhao, Hua

    2015-01-01

    A field study was conducted to compare soil CO2 efflux and CO2 concentration between mulched and non-mulched cotton fields by using closed chamber method and diffusion chamber technique. Soil CO2 efflux and CO2 concentration exhibited a similar seasonal pattern, decreasing from July to October. Mulched field had a lower soil CO2 efflux but a higher CO2 concentration, compared to those of non-mulched fields. Over the measurement period, cumulative CO2 efflux was 1871.95 kg C . hm-2 for mulched field and 2032.81 kg C . hm-2 for non-mulched field. Soil CO2 concentration was higher in mulched field (ranging from 5137 to 25945 µL . L-1) than in non- mulched field (ranging from 2165 to 23986 µL . L-1). The correlation coefficients between soil CO2 concentrations at different depths and soil CO2 effluxes were 0.60 to 0.73 and 0.57 to 0.75 for the mulched and non-mulched fields, indicating that soil CO2 concentration played a crucial role in soil CO2 emission. The Q10 values were 2.77 and 2.48 for the mulched and non-mulched fields, respectively, suggesting that CO2 efflux in mulched field was more sensitive to the temperature.

  15. CO2 (dry ice) cleaning system

    Science.gov (United States)

    Barnett, Donald M.

    1995-01-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system