WorldWideScience

Sample records for silicon-silicon dioxide structures

  1. Defects and defect generation in oxide layer of ion implanted silicon-silicon dioxide structures

    CERN Document Server

    Baraban, A P

    2002-01-01

    One studies mechanism of generation of defects in Si-SiO sub 2 structure oxide layer as a result of implantation of argon ions with 130 keV energy and 10 sup 1 sup 3 - 3.2 x 10 sup 1 sup 7 cm sup - sup 2 doses. Si-SiO sub 2 structures are produced by thermal oxidation of silicon under 950 deg C temperature. Investigations were based on electroluminescence technique and on measuring of high-frequency volt-farad characteristics. Increase of implantation dose was determined to result in spreading of luminosity centres and in its maximum shifting closer to boundary with silicon. Ion implantation was shown, as well, to result in increase of density of surface states at Si-SiO sub 2 interface. One proposed model of defect generation resulting from Ar ion implantation into Si-SiO sub 2

  2. Study of Silicon/silicon, Silicon/silicon Dioxide, and Metal-Oxide

    Science.gov (United States)

    Leung, To Chi

    A variable-energy positron beam is used to study Si/Si, Si/SiO_2, and metal-oxide -semiconductor (MOS) structures. The capability of depth resolution and the remarkable sensitivity to defects have made the positron annihilation technique a unique tool in detecting open-volume defects in the newly innovated low temperature (300^circC) molecular-beam-epitaxy (MBE) Si/Si. These two features of the positron beam have further shown its potential role in the study of the Si/SiO_2. Distinct annihilation characteristics has been observed at the interface and has been studied as a function of the sample growth conditions, annealing (in vacuum), and hydrogen exposure. The MOS structure provides an effective way to study the electrical properties of the Si/SiO_2 interface as a function of applied bias voltage. The annihilation characteristics show a large change as the device condition is changed from accumulation to inversion. The effect of forming gas (FG) anneal is studied using positron annihilation and the result is compared with capacitance-voltage (C -V) measurements. The reduction in the number of interface states is found correlated with the changes in the positron spectra. The present study shows the importance of the positron annihilation technique as a non-contact, non-destructive, and depth-sensitive characterization tool to study the Si-related systems, in particular, the Si/SiO_2 interface which is of crucial importance in semiconductor technology, and fundamental understanding of the defects responsible for degradation of the electrical properties.

  3. CHARACTERIZATION OF THE ELECTROPHYSICAL PROPERTIES OF SILICON-SILICON DIOXIDE INTERFACE USING PROBE ELECTROMETRY METHODS

    Directory of Open Access Journals (Sweden)

    V. А. Pilipenko

    2017-01-01

    Full Text Available Introduction of submicron design standards into microelectronic industry and a decrease of the gate dielectric thickness raise the importance of the analysis of microinhomogeneities in the silicon-silicon dioxide system. However, there is very little to no information on practical implementation of probe electrometry methods, and particularly scanning Kelvin probe method, in the interoperational control of real semiconductor manufacturing process. The purpose of the study was the development of methods for nondestructive testing of semiconductor wafers based on the determination of electrophysical properties of the silicon-silicon dioxide interface and their spatial distribution over wafer’s surface using non-contact probe electrometry methods.Traditional C-V curve analysis and scanning Kelvin probe method were used to characterize silicon- silicon dioxide interface. The samples under testing were silicon wafers of KEF 4.5 and KDB 12 type (orientation <100>, diameter 100 mm.Probe electrometry results revealed uniform spatial distribution of wafer’s surface potential after its preliminary rapid thermal treatment. Silicon-silicon dioxide electric potential values were also higher after treatment than before it. This potential growth correlates with the drop in interface charge density. At the same time local changes in surface potential indicate changes in surface layer structure.Probe electrometry results qualitatively reflect changes of interface charge density in silicon-silicon dioxide structure during its technological treatment. Inhomogeneities of surface potential distribution reflect inhomogeneity of damaged layer thickness and can be used as a means for localization of interface treatment defects.

  4. Effects of ion implantation on charges in the silicon--silicon dioxide system

    International Nuclear Information System (INIS)

    Learn, A.J.; Hess, D.W.

    1977-01-01

    Structures consisting of thermally grown oxide on silicon were implanted with boron, arsenic, or argon ions. For argon implantation through oxides, an increased fixed oxide charge (Q/sub ss/) was observed with the increase being greater for than for silicon. This effect is attributed to oxygen recoil which produces additional excess ionized silicon in the oxide of a type similar to that arising in thermal oxidation. Fast surface state (N/sub st/) generation was also noted which in most cases obscured the Q/sub ss/ increase. Of various heat treatments tested, only a 900 degreeC anneal in hydrogen annihilated N/sub st/ and allowed Q/sub ss/ measurement. Such N/sub st/ apparently arises as a consequence of implantation damage at the silicon--silicon dioxide interface. With the exception of boron implantations into thick oxides or through aluminum electrodes, reduction of the mobile ionic charge (Q/sub o/) was achieved by implantation. The reduction again is presumably damage related and is not negated by high-temperature annealing but may be counterbalanced by aluminum incorporation in the oxide

  5. Thermal Oxidation of Structured Silicon Dioxide

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Jensen, Jørgen Arendt

    2014-01-01

    The topography of thermally oxidized, structured silicon dioxide is investigated through simulations, atomic force microscopy, and a proposed analytical model. A 357 nm thick oxide is structured by removing regions of the oxide in a masked etch with either reactive ion etching or hydrofluoric acid....... Subsequent thermal oxidation is performed in both dry and wet ambients in the temperature range 950◦C to 1100◦C growing a 205 ± 12 nm thick oxide in the etched mask windows. Lifting of the original oxide near the edge of the mask in the range 6 nm to 37 nm is seen with increased lifting for increasing...

  6. Light emitting structures porous silicon-silicon substrate

    International Nuclear Information System (INIS)

    Monastyrskii, L.S.; Olenych, I.B.; Panasjuk, M.R.; Savchyn, V.P.

    1999-01-01

    The research of spectroscopic properties of porous silicon has been done. Complex of photoluminescence, electroluminescence, cathodoluminescence, thermostimulated depolarisation current analyte methods have been applied to study of geterostructures and free layers of porous silicon. Light emitting processes had tendency to decrease. The character of decay for all kinds of luminescence were different

  7. Structure of zirconium dioxide based porous glasses

    Czech Academy of Sciences Publication Activity Database

    Gubanova, N. N.; Kopitsa, G. P.; Ezdakova, K. V.; Baranchikov, A. Y.; Angelov, Borislav; Feoktystov, A.; Pipich, V.; Ryukhtin, Vasyl; Ivanov, V. K.

    2014-01-01

    Roč. 8, č. 5 (2014), s. 967-975 ISSN 1027-4510 R&D Projects: GA ČR GAP208/10/1600; GA MŠk(XE) LM2011019; GA ČR GB14-36566G Institutional support: RVO:61389013 ; RVO:61389005 Keywords : zirconium dioxide * porous glasse * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 0.359, year: 2012

  8. Industrial structural transformation and carbon dioxide emissions in China

    International Nuclear Information System (INIS)

    Zhou, Xiaoyan; Zhang, Jie; Li, Junpeng

    2013-01-01

    Using provincial panel data from the period 1995–2009 to analyze the relationship between the industrial structural transformation and carbon dioxide emissions in China, we find that the first-order lag of industrial structural adjustment effectively reduced the emissions; technical progress itself did not reduce the emissions, but indirectly led to decreasing emissions through the upgrading and optimization of industrial structure. Foreign direct investment and intervention by local governments reduced carbon dioxide emissions, but urbanization significantly increased the emissions. Thus, industrial structural adjustment is an important component of the development of a low-carbon economy. In the context of industrial structural transformation, an effective way to reduce a region’s carbon dioxide emissions is to promote the upgrading and optimization of industrial structure through technical progress. Tighter environmental access policies, selective utilization of foreign direct investment, and improvements in energy efficiency can help to reduce carbon dioxide emissions. - Highlights: ► Relationship between the transformation of industrial structure and CO 2 emissions in China. ► Dynamic panel data model. ► Industrial structural adjustments can effectively reduce current CO 2 emissions. ► Technical progress leads to decreasing CO 2 emissions through upgrading of industrial structure

  9. Strained silicon/silicon germanium heterojunction n-channel metal oxide semiconductor field effect transistors

    International Nuclear Information System (INIS)

    Olsen, Sarah H.

    2002-01-01

    Investigations into the performance of strained silicon/silicon-germanium (Si/SiGe) n-channel metal-oxide-semiconductor field effect transistors (MOSFETs) have been carried out. Theoretical predictions suggest that use of a strained Si/SiGe material system with advanced material properties compared with conventional silicon allows enhanced MOSFET device performance. This study has therefore investigated the practical feasibility of obtaining superior electrical performance using a Si/SiGe material system. The MOSFET devices consisted of a strained Si surface channel and were fabricated on relaxed SiGe material using a reduced thermal budget process in order to preserve the strain. Two batches of strained Si/SiGe devices fabricated on material grown by differing methods have been analysed and both showed good transistor action. A correlation of electrical and physical device data established that the electrical device behaviour was closely related to the SiGe material quality, which differed depending on growth technique. The cross-wafer variation in the electrical performance of the strained Si/SiGe devices was found to be a function of material quality, thus the viability of Si/SiGe MOSFET technology for commercial applications has been addressed. Of particular importance was the finding that large-scale 'cross-hatching' roughness associated with relaxed SiGe alloys led to degradation in the small-scale roughness at the gate oxide interface, which affects electrical device performance. The fabrication of strained Si MOSFET devices on high quality SiGe material thus enabled significant performance gains to be realised compared with conventional Si control devices. In contrast, the performance of devices fabricated on material with severe cross-hatching roughness was found to be diminished by the nanoscale oxide interface roughness. The effect of device processing on SiGe material with differing as-grown roughness has been carried out and compared with the reactions

  10. Segregation of boron implanted into silicon on angular configurations of silicon/silicon dioxide oxidation interface

    CERN Document Server

    Tarnavskij, G A; Obrekht, M S

    2001-01-01

    One studies segregation of boron implanted into silicon when a wave (interface) of oxidation moves within it. There are four types of angular configurations of SiO sub 2 /Si oxidation interface, that is: direct and reverse shoulders, trench type cavities and a square. By means of computer-aided simulation one obtained and analyzed complex patterns of B concentration distribution within Si, SiO sub 2 domains and at SiO sub 2 /Si interface for all types of angular configurations of the oxidation interface

  11. Electronic transport through organophosphonate monolayers on silicon/silicon dioxide substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Achyut; Pathak, Anshuma; Tornow, Marc [Institut fuer Halbleitertechnik, TU Braunschweig (Germany); Liao, Kung-Ching; Schwartz, Jeffrey [Department of Chemistry, Princeton University, NJ (United States); Cattani-Scholz, Anna; Abstreiter, Gerhard [Walter Schottky Institut, TU Muenchen (Germany)

    2011-07-01

    Understanding the electronic transport through layered systems of organic functional layers on semiconductor surfaces is of major importance for future applications in nanoelectronics, photovoltaics and sensors. We have prepared self-assembled monolayers (SAMs) of 9,10-diphenyl-2,6-diphosphono-anthracene and 11-hydroxyundecyl phosphonic acid precursors on highly p-doped silicon surfaces coated with a 1 nm SiO{sub 2} layer. Contact angle, AFM and ellipsometry evidenced the homogeneity of the formed SAMs, and their thickness was determined to be 0.82{+-}0.07 nm and 1.13{+-}0.09 nm, respectively. We provided large area electrical contacts on top of the SAMs by a hanging Hg drop electrode. The measured I-V characteristics revealed an enhanced conductance of the aromatic vs. the aliphatic compounds, with current densities of the order of 10 A/m{sup 2} and 0.01 A/m{sup 2}, at 0.5 V, respectively. We analyzed the data in terms of non-resonant tunneling through the combined oxide-SAM barrier and found good qualitative agreement up to 0.2 V bias. Preliminary measurements on organized bilayers of anthracene bisphosphonates that were grown using techniques of coordination chemistry are discussed, too.

  12. Porous silicon: silicon quantum dots for photonic applications

    International Nuclear Information System (INIS)

    Pavesi, L.; Guardini, R.

    1996-01-01

    Porous silicon formation and structure characterization are briefly illustrated. Its luminescence properties rae presented and interpreted on the basis of exciton recombination in quantum dot structures: the trap-controlled hopping mechanism is used to describe the recombination dynamics. Porous silicon application to photonic devices is considered: porous silicon multilayer in general, and micro cavities in particular are described. The present situation in the realization of porous silicon LEDs is considered, and future developments in this field of research are suggested. (author). 30 refs., 30 figs., 13 tabs

  13. Structure and amphoteric properties of titanium dioxide gels

    International Nuclear Information System (INIS)

    Kertesz, C.

    1991-01-01

    Mechanisms responsible for the in-solution ion retention by titanium dioxide are studied. Mineral oxide gel formation and structure are described and various titanium dioxide gel synthesis modes are presented. A two-phase model, taking into account the porous nature of the solid and allowing for the application of the mass action law, is adopted. The oxide amphoteric properties are studied with the potentiometric titration technique. Hysteresis loops are imputed to the slowness of the acid-basic neutralization reaction. The main characteristics are determined: isoelectric point, cation and anion retention capacity. Depending on the suspension agitation, the speed limiting factor may be the diffusion in the film or the diffusion in the particle. 60 fig., 128 ref

  14. Optical modulation in silicon-vanadium dioxide photonic structures

    Science.gov (United States)

    Miller, Kevin J.; Hallman, Kent A.; Haglund, Richard F.; Weiss, Sharon M.

    2017-08-01

    All-optical modulators are likely to play an important role in future chip-scale information processing systems. In this work, through simulations, we investigate the potential of a recently reported vanadium dioxide (VO2) embedded silicon waveguide structure for ultrafast all-optical signal modulation. With a VO2 length of only 200 nm, finite-differencetime- domain simulations suggest broadband (200 nm) operation with a modulation greater than 12 dB and an insertion loss of less than 3 dB. Predicted performance metrics, including modulation speed, modulation depth, optical bandwidth, insertion loss, device footprint, and energy consumption of the proposed Si-VO2 all-optical modulator are benchmarked against those of current state-of-the-art all-optical modulators with in-plane optical excitation.

  15. Gamma Radiation Dosimetry Using Tellurium Dioxide Thin Film Structures

    Directory of Open Access Journals (Sweden)

    Olga Korostynska

    2002-08-01

    Full Text Available Thin films of Tellurium dioxide (TeO2 were investigated for γ-radiation dosimetry purposes. Samples were fabricated using thin film vapour deposition technique. Thin films of TeO2 were exposed to a 60Co γ-radiation source at a dose rate of 6 Gy/min at room temperature. Absorption spectra for TeO2 films were recorded and the values of the optical band gap and energies of the localized states for as-deposited and γ-irradiated samples were calculated. It was found that the optical band gap values were decreased as the radiation dose was increased. Samples with electrical contacts having a planar structure showed a linear increase in current values with the increase in radiation dose up to a certain dose level. The observed changes in both the optical and the electrical properties suggest that TeO2 thin film may be considered as an effective material for room temperature real time γ-radiation dosimetry.

  16. Electronic structure of the actinides and their dioxides. Application to the defect formation energy and krypton solubility in uranium dioxide

    International Nuclear Information System (INIS)

    Petit, T.; CEA Centre d'Etudes de Grenoble, 38

    1996-01-01

    Uranium dioxide is the standard nuclear fuel used in French h power plants. During irradiation, fission products such as krypton and xenon are created inside fuel pellets. So, gas release could become, at very high burnup, a limiting factor in the reactor exploitation. To study this subject, we have realised calculations using the Density Functional Theory (DFT) into the Local Density Approximation (LDA) and the Atomic Sphere Approximation (ASA). First, we have validated our approach by calculating cohesive properties of thorium, protactinium and uranium metals. The good agreement between our results and experimental values implies that 5f electrons are itinerant. Calculated lattice parameter, cohesive energy and bulk modulus for uranium and thorium dioxides are in very good agreement with experiment. We show that binding between uranium and oxygen atoms is not completely ionic but partially covalent. The question of the electrical conductivity still remains an open problem. We have been able to calculate punctual defect formation energies in uranium dioxide. Accordingly to experimental observations, we find that it is easier to create a defect in the oxygen sublattice than in the uranium sublattice. Finally, we have been able to predict a probable site of krypton atoms in nuclear fuel: the Schottky trio. Experiences of Extended X-ray Absorption Fine structure Spectroscopy (EXAFS) and X-ray Photoelectron Spectroscopy (XPS) on uranium dioxide doped by ionic implantation will help us in the comprehension of the studied phenomena and the interpretation of our calculations. (author)

  17. Structural modeling and intermolecular correlation of liquid chlorine dioxide

    International Nuclear Information System (INIS)

    Ogata, Norio; Hironori, Shimakura; Kawakita, Yukinobu; Ohara, Yukoji; Kohara, Shinji; Takeda, Shinichi

    2009-01-01

    Chlorine dioxide (ClO 2 ) is water-soluble yellow gas at room temperature. It has long been used as a disinfectant of tap water and various commodities owing to its strong oxidizing activity against various microbial proteins. The oxidizing activity is believed to be due to the presence of unpaired electron in its molecular orbital. Despite wealth of physicochemical studies of gaseous ClO 2 , little is known about liquid ClO 2 , especially about fine molecular structure and intermolecular interactions of liquid ClO 2 . The purpose of this study is to elucidate the fine structure and intermolecular orientations of ClO 2 molecules in its liquid state using a high-energy X-ray diffraction technique. The measurements of liquid ClO 2 were carried out at -50 to 0 degree Celsius using a two-axis diffractometer installed at the BL04B2 beamline in the third-generation synchrotron radiation facility SPring-8 (Hyogo, Japan). The incident X-ray beamline was 113.4 keV in energy and 0.1093 Armstrong in wavelength from a Si(111) monochromator with the third harmonic reflection. Liquid ClO 2 held in a quartz capillary tube was placed in a temperature-controlled vacuum chamber. We obtained a structure factor S(Q) to a range of Q = 0.3-30 Amstrong -1 and a pair distribution function g(r) upon Fourier transform of the S(Q). The total g(r) showed peaks at 1.46, 2.08, 2.48, 3.16 and 4.24 Armstrong. From intramolecular bond lengths of 1.46 Armstrong for Cl-O and 2.48 Armstrong for O-O, O-Cl-O bond angle was estimated to be 116.1 degrees. Peaks at 3.16 and 4.24 Armstrong in the total g(r) strongly indicate presence of specific intermolecular orientations of ClO 2 molecules that are distinct from those observed as a dimer in the solid phase ClO 2 . This view was further supported by molecular simulation using a reverse Monte Carlo method (RMC). (author)

  18. Nanocomposites based on titanium dioxide and polythiophene: structure and properties

    Czech Academy of Sciences Publication Activity Database

    Vu, Q. T.; Pavlík, Martin; Hebestreit, N.; Rammelt, U.; Plieth, W.; Pfleger, Jiří

    2005-01-01

    Roč. 65, 1-2 (2005), s. 69-77 ISSN 1381-5148. [International Conference on Polymers and Organic Chemistry /11./. Prague, 18.06.2004-23.06.2004] R&D Projects: GA AV ČR IAA4050406 Grant - others:European Graduate School: Advanced Polymeric Materials(XE) IGK720 Institutional research plan: CEZ:AV0Z40500505 Keywords : polythiophene * titanium dioxide * nanocomposites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.565, year: 2005

  19. The fabrication and visible-near-infrared optical modulation of vanadium dioxide/silicon dioxide composite photonic crystal structure

    Science.gov (United States)

    Liang, Jiran; Li, Peng; Song, Xiaolong; Zhou, Liwei

    2017-12-01

    We demonstrated a visible and near-infrared light tunable photonic nanostructure, which is composed of vanadium dioxide (VO2) thin film and silicon dioxide (SiO2) ordered nanosphere arrays. The vanadium films were sputtered on two-dimensional (2D) SiO2 sphere arrays. VO2 thin films were prepared by rapid thermal annealing (RTA) method with different oxygen flow rates. The close-packed VO2 shell formed a continuous surface, the composition of VO2 films in the structure changed when the oxygen flow rates increased. The 2D VO2/SiO2 composite photonic crystal structure exhibited transmittance trough tunability and near-infrared (NIR) transmittance modulation. When the oxygen flow rate increased from 3 slpm to 4 slpm, the largest transmittance trough can be regulated from 904 to 929 nm at low temperature, the transmittance troughs also appear blue shift when the VO2 phase changes from insulator to metal. The composite nanostructure based on VO2 films showed visible transmittance tunability, which would provide insights into the glass color changing in smart windows.

  20. The fabrication and visible-near-infrared optical modulation of vanadium dioxide/silicon dioxide composite photonic crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jiran; Li, Peng; Song, Xiaolong; Zhou, Liwei [Tianjin University, School of Microelectronics, Tianjin (China)

    2017-12-15

    We demonstrated a visible and near-infrared light tunable photonic nanostructure, which is composed of vanadium dioxide (VO{sub 2}) thin film and silicon dioxide (SiO{sub 2}) ordered nanosphere arrays. The vanadium films were sputtered on two-dimensional (2D) SiO{sub 2} sphere arrays. VO{sub 2} thin films were prepared by rapid thermal annealing (RTA) method with different oxygen flow rates. The close-packed VO{sub 2} shell formed a continuous surface, the composition of VO{sub 2} films in the structure changed when the oxygen flow rates increased. The 2D VO{sub 2}/SiO{sub 2} composite photonic crystal structure exhibited transmittance trough tunability and near-infrared (NIR) transmittance modulation. When the oxygen flow rate increased from 3 slpm to 4 slpm, the largest transmittance trough can be regulated from 904 to 929 nm at low temperature, the transmittance troughs also appear blue shift when the VO{sub 2} phase changes from insulator to metal. The composite nanostructure based on VO{sub 2} films showed visible transmittance tunability, which would provide insights into the glass color changing in smart windows. (orig.)

  1. Experimental study on influence of carbon dioxide on porous structure and mechanical properties of shale rock

    Directory of Open Access Journals (Sweden)

    Danuta Miedzińska

    2017-12-01

    Full Text Available Shale rocks are geological formations which can be unconventional gas reservoirs. During their interaction with carbon dioxide, which can be used as a fracturing fluid in shale gas recovery process, many phenomena take place that can influence rock structure and mechanical properties. The research on changes in rock structure under super critical carbon dioxide interaction and their influence of shale properties were presented in the paper. The structural tests were carried out with the use of microscopic techniques with different resolutions of visualization. The uniaxial compression test was applied as a mechanical properties’ assessment experiment. As a result of research, some dependence was observed. The bigger decrease was in porosity after infiltration in lower zooms, the bigger increase in porosity in high zooms and mechanical properties was noticed. Keywords: geomechanics, shale rock, carbon dioxide

  2. A Revival of Waste: Atmospheric Pressure Nitrogen Plasma Jet Enhanced Jumbo Silicon/Silicon Carbide Composite in Lithium Ion Batteries.

    Science.gov (United States)

    Chen, Bing-Hong; Chuang, Shang-I; Liu, Wei-Ren; Duh, Jenq-Gong

    2015-12-30

    In this study, a jumbo silicon/silicon carbide (Si/SiC) composite (JSC), a novel anode material source, was extracted from solar power industry cutting waste and used as a material for lithium-ion batteries (LIBs), instead of manufacturing the nanolized-Si. Unlike previous methods used for preventing volume expansion and solid electrolyte interphase (SEI), the approach proposed here simply entails applying surface modification to JSC-based electrodes by using nitrogen-atmospheric pressure plasma jet (N-APPJ) treatment process. Surface organic bonds were rearranged and N-doped compounds were formed on the electrodes through applying different plasma treatment durations, and the qualitative examinations of before/after plasma treatment were identified by X-ray photoelectron spectroscopy (XPS) and electron probe microanalyzer (EPMA). The surface modification resulted in the enhancement of electrochemical performance with stable capacity retention and high Coulombic efficiency. In addition, depth profile and scanning electron microscope (SEM) images were executed to determine the existence of Li-N matrix and how the nitrogen compounds change the surface conditions of the electrodes. The N-APPJ-induced rapid surface modification is a major breakthrough for processing recycled waste that can serve as anode materials for next-generation high-performance LIBs.

  3. Sulfur cathodes with hydrogen reduced titanium dioxide inverse opal structure.

    Science.gov (United States)

    Liang, Zheng; Zheng, Guangyuan; Li, Weiyang; Seh, Zhi Wei; Yao, Hongbin; Yan, Kai; Kong, Desheng; Cui, Yi

    2014-05-27

    Sulfur is a cathode material for lithium-ion batteries with a high specific capacity of 1675 mAh/g. The rapid capacity fading, however, presents a significant challenge for the practical application of sulfur cathodes. Two major approaches that have been developed to improve the sulfur cathode performance include (a) fabricating nanostructured conductive matrix to physically encapsulate sulfur and (b) engineering chemical modification to enhance binding with polysulfides and, thus, to reduce their dissolution. Here, we report a three-dimensional (3D) electrode structure to achieve both sulfur physical encapsulation and polysulfides binding simultaneously. The electrode is based on hydrogen reduced TiO2 with an inverse opal structure that is highly conductive and robust toward electrochemical cycling. The relatively enclosed 3D structure provides an ideal architecture for sulfur and polysulfides confinement. The openings at the top surface allow sulfur infusion into the inverse opal structure. In addition, chemical tuning of the TiO2 composition through hydrogen reduction was shown to enhance the specific capacity and cyclability of the cathode. With such TiO2 encapsulated sulfur structure, the sulfur cathode could deliver a high specific capacity of ∼1100 mAh/g in the beginning, with a reversible capacity of ∼890 mAh/g after 200 cycles of charge/discharge at a C/5 rate. The Coulombic efficiency was also maintained at around 99.5% during cycling. The results showed that inverse opal structure of hydrogen reduced TiO2 represents an effective strategy in improving lithium sulfur batteries performance.

  4. Controlled Synthesis of Manganese Dioxide Nano structures via a Facile Hydrothermal

    International Nuclear Information System (INIS)

    Pang, R.S.C.; Chin, S.F.; Ye, Ch. Ling

    2012-01-01

    Manganese dioxide nano structures with controllable morphological structures and crystalline phases were synthesized via a facile hydrothermal route at low temperatures without using any templates or surfactants. Both the aging duration and aging temperatures were the main synthesis parameters used to influence and control the rate of morphological and structural evolution of MnO 2 nano structures. MnO 2 nano structures comprise of spherical nano particulate agglomerates and highly amorphous in nature were formed at lower temperature and/or short aging duration. In contrast, MnO 2 nano structures of sea-urchin-like and nano rods-like morphologies and nanocrystalline in nature were prepared at the combined higher aging temperatures and longer aging durations. These nano structures underwent notable phase transformation from d-MnO 2 to a-MnO 2 upon prolonged hydrothermal aging duration and exhibited accelerated rate of phase transformation at higher aging temperature.

  5. The silicon-silicon oxide multilayers utilization as intrinsic layer on pin solar cells

    International Nuclear Information System (INIS)

    Colder, H.; Marie, P.; Gourbilleau, F.

    2008-01-01

    Silicon nanostructures are promising candidate for the intrinsic layer on pin solar cells. In this work we report on new material: silicon-rich silicon oxide (SRSO) deposited by reactive magnetron sputtering of a pure silica target and an interesting structure: multilayers consisting of a stack of SRSO and pure silicon oxide layers. Two thicknesses of the SRSO sublayer, t SRSO , are studied 3 nm and 5 nm whereas the thickness of silica sublayer is maintaining at 3 nm. The presence of nanocrystallites of silicon, evidenced by X-Ray diffraction (XRD), leads to photoluminescence (PL) emission at room temperature due to the quantum confinement of the carriers. The PL peak shifts from 1.3 eV to 1.5 eV is correlated to the decreasing of t SRSO from 5 nm down to 3 nm. In the purpose of their potential utilization for i-layer, the optical properties are studied by absorption spectroscopy. The achievement a such structures at promising absorption properties. Moreover by favouring the carriers injection by the tunnel effect between silicon nanograins and silica sublayers, the multilayers seem to be interesting for solar cells

  6. The (2 × 2) tunnels structured manganese dioxide nanorods with α phase for lithium air batteries

    Science.gov (United States)

    Ghouri, Zafar Khan; Zahoor, Awan; Barakat, Nasser A. M.; Alsoufi, Mohammad S.; Bawazeer, Tahani M.; Mohamed, Ahmed F.; Kim, Hak Yong

    2016-02-01

    The (2 × 2) tunnels structured manganese dioxide nanorods with α phase (α-MnO2) are synthesized via simplistic hydrothermal method at low temperature. The obtained tunnels structured α-MnO2 nanorods are characterized by, Transmission electron microscopy, Scanning electron microscopy, and X-ray diffraction techniques. The oxygen reduction reaction (ORR) activity was studied by cyclic voltammetry and rotating ring-disc electrode voltammetry techniques in alkaline media. Moreover; the highly electrocatalytic tunnels structured α-MnO2 nanorods were then also applied as cathode in rechargeable Li-O2 cells. The Li-O2 cells exhibited initial discharge capacity as high as ∼4000 mAh/g with the tunnels structured α-MnO2 nanorods which was double the original capacity of the cells without any catalyst. Also we obtained 100% round trip efficiency upon cycling with limited capacity for more than 50 cycles.

  7. Relativistic band-structure calculations for electronic properties of actinide dioxides

    International Nuclear Information System (INIS)

    Maehira, Takahiro; Hotta, Takashi

    2007-01-01

    Energy band structures of actinide dioxides AnO 2 (An=Th, U, Np, and Pu) are investigated by a relativistic linear augmented-plane-wave method with the exchange-correlation potential in a local density approximation (LDA). It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the hybridization between actinide 5f and oxygen 2p electrons. By focusing on the crystalline electric field states, we point out the problem in the application of the LDA to AnO 2

  8. Microwave assisted growth of nanorods vanadium dioxide VO2 (R): structural and electrical properties

    Science.gov (United States)

    Derkaoui, I.; Khenfouch, M.; Mothudi, B. M.; Moloi, S. J.; Zorkani, I.; Jorio, A.; Maaza, M.

    2018-03-01

    Nanostructured metal oxides have attracted a lot of attention recently owning to their unique structural advantages and demonstrated promising chemical and physical properties for various applications. In this study, we report the structural and electrical properties of vanadium dioxide VO2 (R) prepared via a single reaction microwave (SRC) synthesis. Our results are revealing that the components of VO2 (R) films have a rod-like shape with a uniform size distribution. The nanorods with very smooth and flat surfaces have a typical length of up to 2μm and a width of about several nanometers. The structural investigations reveal the high crystallinity of VO2 (R) ensuring good electrical contact and showing a high conductivity as a function of temperature. This synthesis method provides a new simple route to fabricate one-dimensional nanostructured metal oxides which is suitable for a large field of applications especially for smart windows.

  9. Various continuum approaches for studying shock wave structure in carbon dioxide

    Science.gov (United States)

    Alekseev, I. V.; Kosareva, A. A.; Kustova, E. V.; Nagnibeda, E. A.

    2018-05-01

    Shock wave structure in carbon dioxide is studied using different continuum models within the framework of one-temperature thermal equilibrium flow description. Navier-Stokes and Euler equations as well as commonly used Rankine-Hugoniot equations with different specific heat ratios are used to find the gas-dynamic parameters behind the shock wave. The accuracy of the Rankine-Hugoniot relations in polyatomic gases is assessed, and it is shown that they give a considerable error in the predicted values of fluid-dynamic variables. The effect of bulk viscosity on the shock wave structure in CO2 is evaluated. Taking into account bulk viscosity yields a significant increase in the shock wave width; for the complete model, the shock wave thickness varies non-monotonically with the Mach number.

  10. Structure-Activity Relationships for Rates of Aromatic Amine Oxidation by Manganese Dioxide.

    Science.gov (United States)

    Salter-Blanc, Alexandra J; Bylaska, Eric J; Lyon, Molly A; Ness, Stuart C; Tratnyek, Paul G

    2016-05-17

    New energetic compounds are designed to minimize their potential environmental impacts, which includes their transformation and the fate and effects of their transformation products. The nitro groups of energetic compounds are readily reduced to amines, and the resulting aromatic amines are subject to oxidation and coupling reactions. Manganese dioxide (MnO2) is a common environmental oxidant and model system for kinetic studies of aromatic amine oxidation. In this study, a training set of new and previously reported kinetic data for the oxidation of model and energetic-derived aromatic amines was assembled and subjected to correlation analysis against descriptor variables that ranged from general purpose [Hammett σ constants (σ(-)), pKas of the amines, and energies of the highest occupied molecular orbital (EHOMO)] to specific for the likely rate-limiting step [one-electron oxidation potentials (Eox)]. The selection of calculated descriptors (pKa, EHOMO, and Eox) was based on validation with experimental data. All of the correlations gave satisfactory quantitative structure-activity relationships (QSARs), but they improved with the specificity of the descriptor. The scope of correlation analysis was extended beyond MnO2 to include literature data on aromatic amine oxidation by other environmentally relevant oxidants (ozone, chlorine dioxide, and phosphate and carbonate radicals) by correlating relative rate constants (normalized to 4-chloroaniline) to EHOMO (calculated with a modest level of theory).

  11. Structure-Activity Relationships for Rates of Aromatic Amine Oxidation by Manganese Dioxide

    International Nuclear Information System (INIS)

    Salter-Blanc, Alexandra J.; Lyon, Molly A.; Science University, Portland, OR; Ness, Stuart C.; Science University, Portland, OR; Tratnyek, Paul G.; Science University, Portland, OR

    2016-01-01

    New energetic compounds are designed to minimize their potential environmental impacts, which includes their transformation and the fate and effects of their transformation products. The nitro groups of energetic compounds are readily reduced to amines, and the resulting aromatic amines are subject to oxidation and coupling reactions. Manganese dioxide (MnO 2 ) is a common environmental oxidant and model system for kinetic studies of aromatic amine oxidation. Here in this study, a training set of new and previously reported kinetic data for the oxidation of model and energetic-derived aromatic amines was assembled and subjected to correlation analysis against descriptor variables that ranged from general purpose [Hammett σ constants (σ − ), pK a s of the amines, and energies of the highest occupied molecular orbital (E HOMO )] to specific for the likely rate-limiting step [one-electron oxidation potentials (E ox )]. The selection of calculated descriptors (pK a ), E HOMO , and E ox ) was based on validation with experimental data. All of the correlations gave satisfactory quantitative structure-activity relationships (QSARs), but they improved with the specificity of the descriptor. The scope of correlation analysis was extended beyond MnO 2 to include literature data on aromatic amine oxidation by other environmentally relevant oxidants (ozone, chlorine dioxide, and phosphate and carbonate radicals) by correlating relative rate constants (normalized to 4-chloroaniline) to E HOMO (calculated with a modest level of theory).

  12. Energetics of intrinsic point defects in uranium dioxide from electronic-structure calculations

    International Nuclear Information System (INIS)

    Nerikar, Pankaj; Watanabe, Taku; Tulenko, James S.; Phillpot, Simon R.; Sinnott, Susan B.

    2009-01-01

    The stability range of intrinsic point defects in uranium dioxide is determined as a function of temperature, oxygen partial pressure, and non-stoichiometry. The computational approach integrates high accuracy ab initio electronic-structure calculations and thermodynamic analysis supported by experimental data. In particular, the density functional theory calculations are performed at the level of the spin polarized, generalized gradient approximation and includes the Hubbard U term; as a result they predict the correct anti-ferromagnetic insulating ground state of uranium oxide. The thermodynamic calculations enable the effects of system temperature and partial pressure of oxygen on defect formation energy to be determined. The predicted equilibrium properties and defect formation energies for neutral defect complexes match trends in the experimental literature quite well. In contrast, the predicted values for charged complexes are lower than the measured values. The calculations predict that the formation of oxygen interstitials becomes increasingly difficult as higher temperatures and reducing conditions are approached

  13. Modelling and Simulation of Structural Deformation of Isothermal Subsurface Flow and Carbon Dioxide Injection

    KAUST Repository

    El-Amin, Mohamed

    2011-05-15

    Injection of CO2 in hydrocarbon reservoir has double benefit. On the one hand, it is a profitable method due to issues related to global warming, and on the other hand it is an effective mechanism to enhance hydrocarbon recovery. Such injection associates complex processes involving, e.g., solute transport of dissolved materials, in addition to local changes in density of the phases. Also, increasing carbon dioxide injection may cause a structural deformation of the medium, so it is important to include such effect into the model. The structural deformation modelling in carbon sequestration is important to evaluate the medium stability to avoid CO2 leakage to the atmosphere. On the other hand, geologic formation of the medium is usually heterogeneous and consists of several layers of different permeability. In this work we conduct numerical simulation of two-phase flow in a heterogeneous porous medium domain with dissolved solute transport as well as structural deformation effects. The solute transport of the dissolved component is described by concentration equation. The structural deformation for geomechanics is derived from a general local differential balance equation with neglecting the local mass balance of solid phase and the inertial force term. The flux continuity condition is used at interfaces between different permeability layers of the heterogeneous medium. We analyze the vertical migration of a CO2 plume injected into a 2D layered reservoir. Analysis of distribution of flow field components such as saturation, pressures, velocities, and CO2 concentration are presented.

  14. Investigation of high burnup structures in uranium dioxide applying cellular automata: algorithms and codes

    International Nuclear Information System (INIS)

    Akishina, E.P.; Kostenko, B.F.; Ivanov, V.V.

    2003-01-01

    A new method of research in spatial structures that result from uranium dioxide burning in nuclear reactors of modern atomic plants is suggested. The method is based on the presentation of images of the mentioned structures in the form of the working field of a cellular automaton (CA). First, it has allowed one to extract some important quantitative characteristics of the structures directly from the micrographs of the uranium fuel surface. Secondly, the CA has been found out to allow one to formulate easily the dynamics of the evolution of the studied structures in terms of such micrograph elements as spots, spots' boundaries, cracks, etc. Relation has been found between the dynamics and some exactly solvable models of the theory of cellular automata, in particular, the Ising model and the vote model. This investigation gives a detailed description of some CA algorithms which allow one to perform the fuel surface image processing and to model its evolution caused by burnup or chemical etching. (author)

  15. Membrane-on-a-Chip : Microstructured Silicon/Silicon-Dioxide Chips for High-Throughput Screening of Membrane Transport and Viral Membrane Fusion

    NARCIS (Netherlands)

    Kusters, Ilja; van Oijen, Antoine M.; Driessen, Arnold J. M.

    Screening of transport processes across biological membranes is hindered by the challenge to establish fragile supported lipid bilayers and the difficulty to determine at which side of the membrane reactants reside. Here, we present a method for the generation of suspended lipid bilayers with

  16. Theoretical study using electronic structure calculations of uranium and cerium dioxides containing defects and impurities

    International Nuclear Information System (INIS)

    Shi, Lei

    2016-01-01

    Uranium dioxide (UO_2) is the most widely used nuclear fuel in existing nuclear reactors around the world. While in service for energy supply, UO_2 is submitted to the neutron flux and undergoes nuclear fission chain reactions, which create large number of fission products and point defects. The study of the behavior of the fission products and point defects is important to understand the fuel properties under irradiation. We conduct electronic structure calculations based on the density functional theory (DFT) to model this radiation damage at the atomic scale. The DFT+U method is used to describe the strong correlation of the 4f electrons of cerium and 5f electrons of uranium in the materials studied (UO_2, CeO_2 and (U, Ce)O_2). (U, Ce)O_2 is studied because it is considered as a low radioactive model material of mixed actinide oxides such as the MOX fuel (U, Pu)O_2 used in light water reactors and fast neutron reactors. Cerium dioxide (CeO_2) is studied to provide reference data of (U, Ce)O_2. We perform a DFT+U study of point defects and gaseous fission products (Xe and Kr) in CeO_2 and compare our results to the existing ones of UO_2. We study the bulk properties as well as the behavior of defects for (U, Ce)O_2, and compare our results to the ones of (U, Pu)O_2. Furthermore, for the study of defects in UO_2, methodological improvements are explored considering the spin-orbit coupling effect and the finite-size effect of the simulation supercell. (author) [fr

  17. Investigating the structural changes of uranium dioxide dependent on additives, Phase I - Uranium-oxide system from structural-phase aspect

    International Nuclear Information System (INIS)

    Manojlovic, Lj.

    1962-12-01

    Having in mind the complex structure of the system uranium-oxygen, and that experimental studies of this system lead to controversial conclusions, an extensive review and analysis of the papers published on this subject were needed. This review wold be very useful for interpreting the expected structural changes of the uranium dioxide dependent on the additives

  18. In situ effects of titanium dioxide nanoparticles on community structure of freshwater benthic macroinvertebrates.

    Science.gov (United States)

    Jovanović, Boris; Milošević, Djuradj; Piperac, Milica Stojković; Savić, Ana

    2016-06-01

    For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg(-1) in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Hierarchically structured nanoporous carbon tubes for high pressure carbon dioxide adsorption

    Directory of Open Access Journals (Sweden)

    Julia Patzsch

    2017-05-01

    Full Text Available Mesoscopic, nanoporous carbon tubes were synthesized by a combination of the Stoeber process and the use of electrospun macrosized polystyrene fibres as structure directing templates. The obtained carbon tubes have a macroporous nature characterized by a thick wall structure and a high specific surface area of approximately 500 m²/g resulting from their micro- and mesopores. The micropore regime of the carbon tubes is composed of turbostratic graphitic areas observed in the microstructure. The employed templating process was also used for the synthesis of silicon carbide tubes. The characterization of all porous materials was performed by nitrogen adsorption at 77 K, Raman spectroscopy, infrared spectroscopy, thermal gravimetric analysis (TGA, scanning electron microscopy (SEM as well as transmission electron microscopy (TEM. The adsorption of carbon dioxide on the carbon tubes at 25 °C at pressures of up to 30 bar was studied using a volumetric method. At 26 bar, an adsorption capacity of 4.9 mmol/g was observed. This is comparable to the adsorption capacity of molecular sieves and vertically aligned carbon nanotubes. The high pressure adsorption process of CO2 was found to irreversibly change the microporous structure of the carbon tubes.

  20. Computational characterization of 13C NMR lineshapes of carbon dioxide in structure 1 clathrate hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Dornan, P.; Woo, T.K. [Ottawa Univ., ON (Canada). Dept. of Chemistry

    2008-07-01

    Nonspherical large cages in structure one clathrates impose non-uniform motion of nonspherical guest molecules and anisotropic lineshapes in nuclear magnetic resonance (NMR) spectra of the guest. This paper presented a general method for calculating the chemical shift lineshape anisotropy of guest molecules in clathrate hydrate compounds from molecular dynamics simulations for the case of weak host, guest dipolar coupling. In order to calculate the cage chemical shielding tensors and the NMR lineshape produced by each guest molecule, the study involved the use of orientational distributions from molecular dynamics simulation along with time and powder angle averaging. The total predicted lineshape anisotropy was calculated from the superposition of the lineshapes of all guests. The approach was applied to calculate the temperature dependent 13C NMR lineshape anisotropy of carbon dioxide in structure 1 clathrates. The paper presented the computational methodology and results and discussion. It was concluded that the resulting lineshapes were in good agreement with the experimental 13C NMR spectrum at each temperature. The method provided a uniform procedure to calculate the lineshapes at different temperatures and no prior assumptions about the nature of the motion of the guest in cages was required. 37 refs., 2 tabs., 3 figs.

  1. Structural controls on the emission of magmatic carbon dioxide gas, Long Valley Caldera, USA

    Science.gov (United States)

    Lucic, Gregor; Stix, John; Wing, Boswell

    2015-04-01

    We present a degassing study of Long Valley Caldera that explores the structural controls upon emissions of magmatic carbon dioxide gas. A total of 223 soil gas samples were collected and analyzed for stable carbon isotopes using a field-portable cavity ring-down spectrometer. This novel technique is flexible, accurate, and provides sampling feedback on a daily basis. Sampling sites included major and minor volcanic centers, regional throughgoing faults, caldera-related structures, zones of elevated seismicity, and zones of past and present hydrothermal activity. The classification of soil gases based on their δ13C and CO2 values reveals a mixing relationship among three end-members: atmospheric, biogenic, and magmatic. Signatures dominated by biogenic contributions (~4 vol %, -24‰) are found on the caldera floor, the interior of the resurgent dome, and areas associated with the Hilton Creek and Hartley Springs fault systems. With the introduction of the magmatic component (~100 vol %, -4.5‰), samples acquire mixing and hydrothermal signatures and are spatially associated with the central caldera and Mammoth Mountain. In particular, they are concentrated along the southern margin of the resurgent dome where the interplay between resurgence-related reverse faulting and a bend in the regional fault system has created a highly permeable fracture network, suitable for the formation of shallow hydrothermal systems. This contrasts with the south moat, where despite elevated seismicity, a thick sedimentary cover has formed an impermeable cap, inhibiting the ascent of fluids and gases to the surface.

  2. Computer simulation of structural modifications induced by highly energetic ions in uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Sasajima, Y., E-mail: sasajima@mx.ibaraki.ac.jp [Department of Materials Science and Engineering, Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi 316-8511 (Japan); Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Shirakata 162-4, Tokai 319-1106 (Japan); Osada, T. [Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi 316-8511 (Japan); Ishikawa, N. [Japan Atomic Energy Agency (JAEA), Shirakata Shirane 2-4, Tokai 319-1195 (Japan); Iwase, A. [Department of Materials Science, Osaka Prefecture University, Gakuen-cho 1-1, Sakai 599-8531 (Japan)

    2013-11-01

    The structural modification caused by the high-energy-ion irradiation of single-crystalline uranium dioxide was simulated by the molecular dynamics method. As the initial condition, high kinetic energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Basak et al. [C.B. Basak, A.K. Sengupta, H.S. Kamath, J. Alloys Compd. 360 (2003) 210–216] was utilized to calculate interaction between atoms. The supplied kinetic energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. The amorphous track radius R{sub a} was determined as a function of the effective stopping power gS{sub e}, i.e., the kinetic energy of atoms per unit length created by ion irradiation (S{sub e}: electronic stopping power, g: energy transfer ratio from stopping power to lattice vibration energy). It was found that the relationship between R{sub a} and gS{sub e} follows the relation R{sub a}{sup 2}=aln(gS{sub e})+b. Compared to the case of Si and β-cristobalite single crystals, it was harder to produce amorphous track because of the long range interaction between U atoms.

  3. Computer simulation of structural modifications induced by highly energetic ions in uranium dioxide

    International Nuclear Information System (INIS)

    Sasajima, Y.; Osada, T.; Ishikawa, N.; Iwase, A.

    2013-01-01

    The structural modification caused by the high-energy-ion irradiation of single-crystalline uranium dioxide was simulated by the molecular dynamics method. As the initial condition, high kinetic energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Basak et al. [C.B. Basak, A.K. Sengupta, H.S. Kamath, J. Alloys Compd. 360 (2003) 210–216] was utilized to calculate interaction between atoms. The supplied kinetic energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. The amorphous track radius R a was determined as a function of the effective stopping power gS e , i.e., the kinetic energy of atoms per unit length created by ion irradiation (S e : electronic stopping power, g: energy transfer ratio from stopping power to lattice vibration energy). It was found that the relationship between R a and gS e follows the relation R a 2 =aln(gS e )+b. Compared to the case of Si and β-cristobalite single crystals, it was harder to produce amorphous track because of the long range interaction between U atoms

  4. Structure and dielectric properties in the radio frequency range of polymer composites based on vanadium dioxide

    Directory of Open Access Journals (Sweden)

    Kolbunov V.R.

    2015-06-01

    Full Text Available Polymer composites with active fillers are recently considered to be promising materials for the design of new functional devices with controllable properties and are intensively investigated. Dielectric studies are one of the most effective methods for studying structural features and mechanisms of conductivity formation for this type of two-component systems. The paper presents research results of the dielectric characteristics in the range of radio frequency of 50 kHz — 10 MHz and temperature range of 30—60°C of polyethylene composites of vanadium dioxide with different volume fractions of filler. Two dispersion areas were found: a high-frequency area caused by the Maxwell charge separation on the boundaries of the polyethylene matrix — conductive filler of VI2 crystallites, and a low frequency area associated with the presence of the transition layer at this boundary. The relative permittivity of the composite has a tendency to a decrease in absolute value with increasing temperature. The analysis of the low-frequency dependence of the dielectric constant of the value of the filler’s volume fraction revealed that the investigated composite belongs to two-component statistical mixtures with a transition layer between the components.

  5. Electronic structure calculations of atomic transport properties in uranium dioxide: influence of strong correlations

    International Nuclear Information System (INIS)

    Dorado, B.

    2010-09-01

    Uranium dioxide UO 2 is the standard nuclear fuel used in pressurized water reactors. During in-reactor operation, the fission of uranium atoms yields a wide variety of fission products (FP) which create numerous point defects while slowing down in the material. Point defects and FP govern in turn the evolution of the fuel physical properties under irradiation. In this study, we use electronic structure calculations in order to better understand the fuel behavior under irradiation. In particular, we investigate point defect behavior, as well as the stability of three volatile FP: iodine, krypton and xenon. In order to take into account the strong correlations of uranium 5f electrons in UO 2 , we use the DFT+U approximation, based on the density functional theory. This approximation, however, creates numerous metastable states which trap the system and induce discrepancies in the results reported in the literature. To solve this issue and to ensure the ground state is systematically approached as much as possible, we use a method based on electronic occupancy control of the correlated orbitals. We show that the DFT+U approximation, when used with electronic occupancy control, can describe accurately point defect and fission product behavior in UO 2 and provide quantitative information regarding point defect transport properties in the oxide fuel. (author)

  6. Structural and magnetic properties of the nanocomposite materials based on a mesoporous silicon dioxide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Grigor’eva, N. A., E-mail: natali@lns.pnpi.spb.ru [St. Petersburg State University (Russian Federation); Eckerlebe, H. [Helmholtz-Zentrum Geesthacht (Germany); Eliseev, A. A.; Lukashin, A. V.; Napol’skii, K. S. [Moscow State University (Russian Federation); Kraje, M. [Reactor Institute Delft (Netherlands); Grigor’ev, S. V. [St. Petersburg State University (Russian Federation)

    2017-03-15

    The structural and magnetic properties of the mesoporous systems based on silicon dioxide with a regular hexagonal arrangement of pores several microns in length and several nanometers in diameter, which are filled with iron compound nanofilaments in various chemical states, are studied in detail. The studies are performed using the following mutually complementary methods: transmission electron microscopy, SQUID magnetometry, electron spin resonance, Mössbauer spectroscopy, polarized neutron small-angle diffraction, and synchrotron radiation diffraction. It is shown that the iron nanoparticles in pores are mainly in the γ phase of Fe{sub 2}O{sub 3} with a small addition of the α phase and atomic iron clusters. The effective magnetic field acting on a nanofilament from other nanofilaments is 11 mT and has a dipole nature, the ferromagnetic–paramagnetic transition temperature is in the range 76–94 K depending on the annealing temperature of the samples, and the temperature that corresponds to the change in the magnetic state of the iron oxide nanofilaments is T ≈ 50–60 K at H = 0 and T ≈ 80 K at H = 300 mT. It is also shown that the magnetization reversal of an array of nanofilaments is caused by the magnetostatic interaction between nanofilaments at the fields that are lower than the saturation field.

  7. Categorization of nano-structured titanium dioxide according to physicochemical characteristics and pulmonary toxicity

    Directory of Open Access Journals (Sweden)

    Naoki Hashizume

    Full Text Available A potentially useful means of predicting the pulmonary risk posed by new forms of nano-structured titanium dioxide (nano-TiO2 is to use the associations between the physicochemical properties and pulmonary toxicity of characterized forms of TiO2. In the present study, we conducted intratracheal administration studies in rats to clarify the associations between the physicochemical characteristics of seven characterized forms of TiO2 and their acute or subacute pulmonary inflammatory toxicity. Examination of the associations between the physicochemical characteristics of the TiO2 and the pulmonary inflammatory responses they induced revealed (1 that differences in the crystallinity or shape of the TiO2 particles were not associated with the acute pulmonary inflammatory response; (2 that particle size was associated with the acute pulmonary inflammatory response; and (3 that TiO2 particles coated with Al(OH3 induced a greater pulmonary inflammatory response than did non-coated particles. We separated the seven TiO2 into two groups: a group containing the six TiO2 with no surface coating and a group containing the one TiO2 with a surface coating. Intratracheal administration to rats of TiO2 from the first group (i.e., non-coated TiO2 induced only acute pulmonary inflammatory responses, and within this group, the acute pulmonary inflammatory response was equivalent when the particle size was the same, regardless of crystallinity or shape. In contrast, intratracheal administration to rats of the TiO2 from the second group (i.e., the coated TiO2 induced a more severe, subacute pulmonary inflammatory response compared with that produced by the non-coated TiO2. Since alteration of the pulmonary inflammatory response by surface treatment may depend on the coating material used, the pulmonary toxicities of coated TiO2 need to be further evaluated. Overall, the present results demonstrate that physicochemical properties may be useful for predicting the

  8. Effects of thickness on the nanocrystalline structure and semiconductor-metal transition characteristics of vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Zhenfei, E-mail: zhfluo8@yahoo.com [Terahertz Research Center, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Zhou, Xun, E-mail: zx_zky@yahoo.com [Terahertz Research Center, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Yan, Dawei [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Wang, Du; Li, Zeyu [Terahertz Research Center, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Yang, Cunbang [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang Sichuan 621900 (China); Jiang, Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2014-01-01

    Nanocrystalline vanadium dioxide (VO{sub 2}) thin films were grown on glass substrates by using reactive direct current magnetron sputtering and in situ thermal treatments at low preparation temperatures (≤ 350 °C). The VO{sub 2} thin films were characterized by grazing-incidence X-ray diffraction, field emission scanning electron microscope, transmission electron microscopy and spectroscopic ellipsometry (SE). The semiconductor-metal transition (SMT) characteristics of the films were investigated by four-point probe resistivity measurements and infrared spectrometer equipped with heating pads. The testing results showed that the crystal structure, morphology, grain size and semiconductor-metal transition temperature (T{sub SMT}) significantly changed as the film thickness decreased. Multilayer structures were observed in the particles of thinner films whose average particle size is much larger than the film thickness and average VO{sub 2} grain size. A competition mechanism between the suppression effect of decreased thickness and coalescence of nanograins was proposed to understand the film growth and the formation of multilayer structure. The value of T{sub SMT} was found to decrease as average VO{sub 2} grain size became smaller, and SE results showed that small nanograin size significantly affected the electronic structure of VO{sub 2} film. - Highlights: • Nanocrystalline vanadium dioxide thin films were prepared. • Multilayer structures were observed in the films with large particles. • The transition temperature of the film is correlated with its electronic structure.

  9. Effects of thickness on the nanocrystalline structure and semiconductor-metal transition characteristics of vanadium dioxide thin films

    International Nuclear Information System (INIS)

    Luo, Zhenfei; Zhou, Xun; Yan, Dawei; Wang, Du; Li, Zeyu; Yang, Cunbang; Jiang, Yadong

    2014-01-01

    Nanocrystalline vanadium dioxide (VO 2 ) thin films were grown on glass substrates by using reactive direct current magnetron sputtering and in situ thermal treatments at low preparation temperatures (≤ 350 °C). The VO 2 thin films were characterized by grazing-incidence X-ray diffraction, field emission scanning electron microscope, transmission electron microscopy and spectroscopic ellipsometry (SE). The semiconductor-metal transition (SMT) characteristics of the films were investigated by four-point probe resistivity measurements and infrared spectrometer equipped with heating pads. The testing results showed that the crystal structure, morphology, grain size and semiconductor-metal transition temperature (T SMT ) significantly changed as the film thickness decreased. Multilayer structures were observed in the particles of thinner films whose average particle size is much larger than the film thickness and average VO 2 grain size. A competition mechanism between the suppression effect of decreased thickness and coalescence of nanograins was proposed to understand the film growth and the formation of multilayer structure. The value of T SMT was found to decrease as average VO 2 grain size became smaller, and SE results showed that small nanograin size significantly affected the electronic structure of VO 2 film. - Highlights: • Nanocrystalline vanadium dioxide thin films were prepared. • Multilayer structures were observed in the films with large particles. • The transition temperature of the film is correlated with its electronic structure

  10. Crystal structure of di-μ-aqua-μ-(pyrazine N,N′-dioxide-κ2O:O-bis(diaquasodium tetraphenylborate dihydrate pyrazine N,N′-dioxide monosolvate

    Directory of Open Access Journals (Sweden)

    Elaine P. Boron

    2015-12-01

    Full Text Available The search for novel lanthanide coordination networks using pyrazine N,N′-dioxide (pzdo, C4H4N2O2 as a structure-directing unit, led to the synthesis and the structure determination of the title compound, [Na2(C4H4N2O2(H2O6][B(C6H54]2·C4H4N2O2·2H2O. The crystal structure is comprised of discrete [{Na(H2O2}2(μ-H2O2(μ-pzdo]2+ cations and tetraphenylborate anions, as well as pzdo and H2O solvent molecules. The dinuclear cation is located about a twofold rotation axis, and the symmetry-related NaI atoms display a distorted square-pyramidal coordination sphere defined by two O atoms of terminal water ligands, two O atoms of bridging water ligands and one O atom of a bridging pzdo ligand. In the crystal, O—H...O hydrogen bonds link the dinuclear cation and solvent pzdo molecules (point-group symmetry -1 into rectangular grid-like layers parallel to the bc plane. Additional C—H...O, O—H...O, C—H...π and O—H...π interactions link the anion and solvent water molecules to the layers. The layers are further linked into a three-dimensional network through a combination of C—H...π and O—H...π hydrogen bonds involving the tetraphenylborate anion.

  11. Surface Properties of Titanium dioxide and its Structural Modifications by Reactions with Transition Metals

    Science.gov (United States)

    Halpegamage, Sandamali

    Surfaces of metal oxides play a vital role in many technologically important applications. The surfaces of titanium dioxide, in particular, show quite promising properties that can be utilized in solid-state gas sensing and photocatalysis applications. In the first part of this dissertation we investigate these properties of TiO2 surfaces through a vigorous surface scientific approach. In the second part, we investigate the possibilities of modifying the TiO2 surfaces by depositing multi-component transition metal oxide monolayers so that the properties of bare TiO2 surface can be influenced in a beneficial way. For instance, via formation of new surface sites or cations that have different valance states, the chemisorption and catalytic properties can be modified. We use sophisticated experimental surface science techniques that are compatible with ultra-high vacuum technology for surface characterization. All the experimental results, except for the photocatalysis experiments, were compared to and verified by supporting DFT-based theoretical results produced by our theory collaborators. TiO2 based solid-state gas sensors have been used before for detecting trace amounts of explosives such as 2,4-dinitrololuene (DNT), a toxic decomposition product of the explosive 2,4,6-trinitrotoluene (TNT) that have very low vapor pressure. However, the adsorption, desorption and reaction mechanism were not well- understood. Here, we investigate 2,4-DNT adsorption on rutile-TiO2(110) surface in order to gain insight about these mechanisms in an atomistic level and we propose an efficient way of desorbing DNT from the surface through UV-light induced photoreactions. TiO2 exists in different polymorphs and the photocatalytic activity differs from one polymorph to another. Rutile and anatase are the most famous forms of TiO2 in photocatalysis and anatase is known to show higher activity than rutile. The photoactivity also varies depending on the surface orientation for the same

  12. Corrosion of Structural Materials for Advanced Supercritical Carbon- Dioxide Brayton Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States)

    2017-05-13

    The supercritical carbon-dioxide (referred to as SC-CO2 hereon) Brayton cycle is being considered for power conversion systems for a number of nuclear reactor concepts, including the sodium fast reactor (SFR), fluoride saltcooled high temperature reactor (FHR), and high temperature gas reactor (HTGR), and several types of small modular reactors (SMR). The SC-CO2 direct cycle gas fast reactor has also been recently proposed. The SC-CO2 Brayton cycle (discussed in Chapter 1) provides higher efficiencies compared to the Rankine steam cycle due to less compression work stemming from higher SC-CO2 densities, and allows for smaller components size, fewer components, and simpler cycle layout. For example, in the case of a SFR using a SC-CO2 Brayton cycle instead of a steam cycle would also eliminate the possibility of sodium-water interactions. The SC-CO2 cycle has a higher efficiency than the helium Brayton cycle, with the additional advantage of being able to operate at lower temperatures and higher pressures. In general, the SC-CO2 Brayton cycle is well-suited for any type of nuclear reactor (including SMR) with core outlet temperature above ~ 500°C in either direct or indirect versions. In all the above applications, materials corrosion in high temperature SC-CO2 is an important consideration, given their expected lifetimes of 20 years or longer. Our discussions with National Laboratories and private industry early on in this project indicated materials corrosion to be one of the significant gaps in the implementation of SC-CO2 Brayton cycle. Corrosion can lead to a loss of effective load-bearing wall thickness of a component and can potentially lead to the generation of oxide particulate debris which can lead to three-body wear in turbomachinery components. Another environmental degradation effect that is rather unique to CO2 environment is the possibility

  13. High performance multilayered nano-crystalline silicon/silicon-oxide light-emitting diodes on glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Darbari, S; Shahmohammadi, M; Mortazavi, M; Mohajerzadeh, S [Thin Film and Nano-Electronic Laboratory, School of ECE, University of Tehran, Tehran (Iran, Islamic Republic of); Abdi, Y [Nano-Physics Research Laboratory, Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Robertson, M; Morrison, T, E-mail: mohajer@ut.ac.ir [Department of Physics, Acadia University, Wolfville, NS (Canada)

    2011-09-16

    A low-temperature hydrogenation-assisted sequential deposition and crystallization technique is reported for the preparation of nano-scale silicon quantum dots suitable for light-emitting applications. Radio-frequency plasma-enhanced deposition was used to realize multiple layers of nano-crystalline silicon while reactive ion etching was employed to create nano-scale features. The physical characteristics of the films prepared using different plasma conditions were investigated using scanning electron microscopy, transmission electron microscopy, room temperature photoluminescence and infrared spectroscopy. The formation of multilayered structures improved the photon-emission properties as observed by photoluminescence and a thin layer of silicon oxy-nitride was then used for electrical isolation between adjacent silicon layers. The preparation of light-emitting diodes directly on glass substrates has been demonstrated and the electroluminescence spectrum has been measured.

  14. Plastic deformation of uranium dioxide: observation of the sub-structures of dislocations

    International Nuclear Information System (INIS)

    Alamo, A.; Lefebvre, J.M.; Soullard, J.

    1978-01-01

    Single crystals of uranium dioxide were deformed in compression at imposed strain rates in the temperature range of 700 0 C to 1400 0 C. The crystals were oriented to promote slip over one or two slip systems of the family [100] and also on the [110] system. Thin films of the deformed specimens were examined by transmission electron microscopy. When [100] single glide system operates, the dislocation substructure consist of numerous dipoles, their edge components lying along directions. For the [100] double glide system the grain boundaries and dislocation hexagonal network are observed, the complexity of which increases with the nominal strain. Dislocation arrangments consisting of extensive cellular networks of tangling dislocations and hexagonal netting were detected for [110] system. The auxillary role of [111] planes on the dislocation cross slip from [100] and [110] system was demonstrated. Weak beam images suggest that dissociation of dislocations can occur. (Auth.)

  15. Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Xiaoliang Wang

    2017-11-01

    Full Text Available Titanium dioxide (TiO2 materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO2 micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO2(B, and summarizes the major advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO2 micro and nano structures, and present the principles and growth mechanisms of TiO2 nanostructures via different strategies, with an emphasis on rational control of the surface and interface structures. We further discuss the applications of TiO2 micro and nano architectures in photocatalysis, lithium/sodium ion batteries, and Li–S batteries. Throughout the discussion, the relationship between the device performance and the surface/interface structures of TiO2 micro and nano structures will be highlighted. Then, we discuss the phase transitions of TiO2 nanostructures and possible strategies of improving the phase stability. The review concludes with a perspective on the current challenges and future research directions.

  16. Insights into the Electronic Structure of Ozone and Sulfur Dioxide from Generalized Valence Bond Theory: Addition of Hydrogen Atoms.

    Science.gov (United States)

    Lindquist, Beth A; Takeshita, Tyler Y; Dunning, Thom H

    2016-05-05

    Ozone (O3) and sulfur dioxide (SO2) are valence isoelectronic species, yet their properties and reactivities differ dramatically. In particular, O3 is highly reactive, whereas SO2 is chemically relatively stable. In this paper, we investigate serial addition of hydrogen atoms to both the terminal atoms of O3 and SO2 and to the central atom of these species. It is well-known that the terminal atoms of O3 are much more amenable to bond formation than those of SO2. We show that the differences in the electronic structure of the π systems in the parent triatomic species account for the differences in the addition of hydrogen atoms to the terminal atoms of O3 and SO2. Further, we find that the π system in SO2, which is a recoupled pair bond dyad, facilitates the addition of hydrogen atoms to the sulfur atom, resulting in stable HSO2 and H2SO2 species.

  17. Comparison of carbon dioxide emissions with fluid upflow, chemistry, and geologic structures at the Rotorua geothermal system, New Zealand

    International Nuclear Information System (INIS)

    Werner, Cynthia; Cardellini, Carlo

    2006-01-01

    During 2002 and 2003, carbon dioxide fluxes were measured across the Rotorua geothermal system in the Taupo Volcanic Zone (TVZ), New Zealand. The results of a 956-measurement survey and of modeling studies show that CO 2 fluxes could be used to determine the main hot fluid upflow areas in Rotorua, and perhaps in undeveloped geothermal regions. Elevated degassing was observed along inferred fault traces and structures, lending confidence to their existence at depth. Degassing was also observed along lineaments that were consistent with the alignment of basement faulting in the TVZ. Areas where elevated degassing was spatially extensive typically overlapped with known regions of hot ground; however, elevated CO 2 fluxes were also observed in isolated patches of non-thermal ground. The total emission rate calculated from sequential Gaussian simulation modeling of CO 2 fluxes across the geothermal system was 620td -1 from an 8.9-km 2 area. However, because approximately one-third of the geothermal system is known to extend beneath Lake Rotorua, we expect the emissions could be minimally on the order of 1000td -1 . Comparing the emission rate with geochemical analyses of geothermal fluids and estimated upflows suggests that the majority of deep carbon reaches the surface in the form of carbon dioxide gas, and that less than one tenth of the CO 2 emissions is dissolved in, or released from, the fluids at depth. Thus, the geothermal reservoir exerts very little control on deep degassing of CO 2 . Carbon isotopic analyses of soil gases suggest a primarily magmatic source for the origin of the CO 2 . The total Rotorua emission rate is comparable to those from active volcanoes such as at White Island, New Zealand, and, when normalized by geothermal area, is comparable to other volcanic and hydrothermal regions worldwide. (author)

  18. The Effect of Annealing on the Structural and Optical Properties of Titanium Dioxide Films Deposited by Electron Beam Assisted PVD

    Directory of Open Access Journals (Sweden)

    Yaser M. Abdulraheem

    2013-01-01

    Full Text Available Titanium dioxide thin films were deposited on crystalline silicon substrates by electron beam physical vapor deposition. The deposition was performed under vacuum ranging from 10−5 to 10−6 Torr without process gases, resulting in homogeneous TiO2-x layers with a thickness of around 100 nm. Samples were then annealed at high temperatures ranging from 500°C to 800°C for 4 hours under nitrogen, and their structural and optical properties along with their chemical structure were characterized before and after annealing. The chemical and structural characterization revealed a substoichiometric TiO2-x film with oxygen vacancies, voids, and an interface oxide layer. It was found from X-ray diffraction that the deposited films were amorphous and crystallization to anatase phase occurred for annealed samples and was more pronounced for annealing temperatures above 700°C. The refractive index obtained through spectroscopic ellipsometry ranged between 2.09 and 2.37 in the wavelength range, 900 nm to 400 nm for the as-deposited sample, and jumped to the range between 2.23 and 2.65 for samples annealed at 800°C. The minimum surface reflectance changed from around 0.6% for the as-deposited samples to 2.5% for the samples annealed at 800°C.

  19. The cohesive energy of uranium dioxide and thorium dioxide

    International Nuclear Information System (INIS)

    Childs, B.G.

    1958-08-01

    Theoretical values have been calculated of the heats of formation of uranium dioxide and thorium dioxide on the assumption that the atomic binding forces in these solids are predominantly ionic in character. The good agreement found between the theoretical and observed values shows that the ionic model may, with care, be used in calculating the energies of defects in the uranium and thorium dioxide crystal structures. (author)

  20. Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

    Science.gov (United States)

    Watson, David; Knox, James C.; West, Phillip; Stanley, Christine M.; Bush, Richard

    2015-01-01

    The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.

  1. Adsorption of Carbon Dioxide onto Tetraethylenepentamine Impregnated PMMA Sorbents with Different Pore Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Dong Hyun; Park, Cheonggi; Jung, Hyunchul; Kim, Sung Hyun [Korea University, Seoul (Korea, Republic of)

    2015-02-15

    Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb CO{sub 2}. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low CO{sub 2} capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for CO{sub 2} capture.

  2. Characterizing the relationship between hyperstoichiometry, defect structure and local corrosion kinetics of uranium dioxide

    International Nuclear Information System (INIS)

    He Heming; Qin, Z.; Shoesmith, D.W.

    2010-01-01

    The ability of the UO 2 fluorite structure to accommodate large amounts of interstitial oxygen in various lattice sites leads to the formation of hyper-stoichiometric phases. The defect structures occurring in hyper-stoichiometric UO 2+x over the range 0.02 ≤ x ≤ 0.1 have been characterized by SEM/EDX and Raman analyses. The results demonstrate that as the nominal stoichiometry increases from 2.002 to 2.1, the diversity of defective structures existing on the UO 2+ surface also increases. Scanning electrochemical microscopy (SECM) measurements combined with a theoretical model were used to determine the rate constant for the reduction of the redox mediator ferrocene methanol, acting as a cathodic oxidant to corrode the four UO 2+x specimens. The rate constant was found to vary with location on the surface. Stoichiometric locations, with a well defined fluorite structure, exhibited very low corrosion rates. Higher rates were observed at more non-stoichiometric locations with the highest rates being obtained on locations exhibiting tetragonal distortions as their composition approached UO 2.33 . The distribution of rates increases with the degree of nominal non-stoichiometry as the diversity of microstructures existing on the UO 2+x surface increases.

  3. Chlorine dioxide as biocide to prevent biofouling in the hydro technical structures at KKNPP

    International Nuclear Information System (INIS)

    Ganesh, S.; Selvaraj, S.; Balasubramanian, M.R.; Selvavinayagam, P.; Sundar, R.S.

    2008-01-01

    Chlorination is envisaged in the sea water systems of KKNPP to control macro and micro bio-fouling of underwater structures and equipments. KKNPP intake and the fore bay structures are shown in detail. The sodium hypo chlorite required for chlorination is produced in the electro chlorination plant at site by the electrolysis of sea water. It is added in the sea water at the intake structure, tunnels and fore bay on continuous as well as periodic basis. The sea water to chlorination plant is supplied by the pumps located at the main pump house. Chlorination of sea water system by electro-chlorination is possible only after pump house flooding and commissioning of electro-chlorination plant. So for the period from breach of temporary dyke till commissioning of electro chlorination plant, chlorination by temporary method has to be done to prevent the bio-fouling of underwater structures and equipments. The flooding of the pump house subsequent to breach of temporary dyke is done

  4. Carbon dioxide emission drivers for a typical metropolis using input–output structural decomposition analysis

    International Nuclear Information System (INIS)

    Wang, Yafei; Zhao, Hongyan; Li, Liying; Liu, Zhu; Liang, Sai

    2013-01-01

    As the capital of China, Beijing is regarded as a major metropolis in the world. Study of the variation in temporal CO 2 emissions generated by the driving forces in Beijing can provide guidance for policy decisions on CO 2 emissions mitigation in global metropolises. Based on input–output structural decomposition analysis (IO-SDA), we analysed the driving forces for the increment in CO 2 emissions in Beijing from both production and final demand perspectives during 1997–2010. According to our results, the CO 2 emission growth in Beijing is driven mainly by production structure change and population growth, partly offset by CO 2 emission intensity reduction as well as the decline in per capita final demand volume during the study period. Final demand structure change has a limited effect on the change in the CO 2 emissions in Beijing. From the final demand perspective, urban trades, urban residential consumption, government consumption and fixed capital formation are mainly responsible for the booming emissions. This study showed how the “top-down” IO-SDA methodology was implemented on a city scale. Policy implications from this study would be helpful for addressing CO 2 emissions mitigation in global capital cities and metropolises. - Highlights: • Changes in production structure and population are drivers of CO 2 increment. • Changes in CO 2 intensity and per capita GDP are forces to offset CO 2 increment. • Final demand structure change has limited effect on Beijing's CO 2 emission change. • Beijing's key final demand categories and economic sectors are identified. • Policy implications of Beijing's results are analyzed

  5. Titanium dioxide fine structures by RF magnetron sputter method deposited on an electron-beam resist mask

    Science.gov (United States)

    Hashiba, Hideomi; Miyazaki, Yuta; Matsushita, Sachiko

    2013-09-01

    Titanium dioxide (TiO2) has been draw attention for wide range of applications from photonic crystals for visible light range by its catalytic characteristics to tera-hertz range by its high refractive index. We present an experimental study of fabrication of fine structures of TiO2 with a ZEP electron beam resist mask followed by Ti sputter deposition techniques. A TiO2 thin layer of 150 nm thick was grown on an FTO glass substrate with a fine patterned ZEP resist mask by a conventional RF magnetron sputter method with Ti target. The deposition was carried out with argon-oxygen gases at a pressure of 5.0 x 10 -1 Pa in a chamber. During the deposition, ratio of Ar-O2 gas was kept to the ratio of 2:1 and the deposition ratio was around 0.5 Å/s to ensure enough oxygen to form TiO2 and low temperature to avoid deformation of fine pattern of the ZPU resist mask. Deposited TiO2 layers are white-transparent, amorphous, and those roughnesses are around 7 nm. Fabricated TiO2 PCs have wider TiO2 slabs of 112 nm width leaving periodic 410 x 410 nm2 air gaps. We also studied transformation of TiO2 layers and TiO2 fine structures by baking at 500 °C. XRD measurement for TiO2 shows that the amorphous TiO2 transforms to rutile and anatase forms by the baking while keeping the same profile of the fine structures. Our fabrication method can be one of a promising technique to optic devices on researches and industrial area.

  6. Structural and optical properties of titanium dioxide films deposited by reactive magnetron sputtering in pure oxygen plasma

    International Nuclear Information System (INIS)

    Asanuma, T.; Matsutani, T.; Liu, C.; Mihara, T.; Kiuchi, M.

    2004-01-01

    Titanium dioxide (TiO 2 ) thin films were deposited on unheated quartz (SiO 2 ) substrates in 'pure oxygen' plasma by reactive radio-frequency (rf) magnetron sputtering. The structural and optical properties of deposited films were systematically studied by changing the deposition parameters, and it was very recently found that crystalline TiO 2 films grew effectively in pure O 2 atmosphere. For TiO 2 films deposited at a rf power P rf of 200 W, x-ray diffraction patterns show the following features: (a) no diffraction peak was observed at a total sputtering pressure p tot of 1.3 Pa; (b) rutile (110) diffraction was observed at 4.0 Pa, (c) the dominant diffraction was from anatase (101) planes, with additional diffraction from (200), under p tot between 6.7 and 13 Pa. For the deposition at 140 W, however, crystalline films with mixed phases were observed only between 4.0 and 6.7 Pa. The peaks of both the deposition rate and the anatase weight ratio for the films produced at 140 W were found at p tot of approximately 6.7 Pa. This suggests that the nucleation and growth of TiO 2 films were affected by the composition, density, and kinetic energy of the particles impinging on the substrate surface. The optical absorption edge analysis showed that the optical band gap E g and the constant B could sensitively detect the film growth behavior, and determine the film structure and optical absorption. The change in the shape of the fundamental absorption edge is considered to reflect the variation of density and the short-range structural modifications

  7. Irreversible Change of the Pore Structure of ZIF-8 in Carbon Dioxide Capture with Water Coexistence

    DEFF Research Database (Denmark)

    Liu, Huang; Guo, Ping; Regueira Muñiz, Teresa

    2016-01-01

    The performance of zeolitic imidazolate framework 8 (ZIF-8) for CO2 capture under three different conditions (wetted ZIF-8, ZIF-8/water slurry, and ZIF-8/water-glycol slurry) was systemically investigated. This investigation included the study of the pore structure stability of ZIF-8 by using X......-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman detection technologies. Our results show that the CO2 adsorption ability of ZIF-8 could be substantially increased under the existence of liquid water. However, the structure characterization of the recovered ZIF-8...... showed an irreversible change of its framework, which occurs during the CO2 capture process. It was found that there is an irreversible chemical reaction among ZIF-8, water, and CO2, which creates both zinc carbonate (or zinc carbonate hydroxides) and single 2-methylimidazole crystals, and therefore...

  8. Structural, electronic, and thermodynamic properties of curium dioxide: Density functional theory calculations

    Science.gov (United States)

    Hou, Ling; Li, Wei-Dong; Wang, Fangwei; Eriksson, Olle; Wang, Bao-Tian

    2017-12-01

    We present a systematic investigation of the structural, magnetic, electronic, mechanical, and thermodynamic properties of CmO2 with the local density approximation (LDA)+U and the generalized gradient approximation (GGA)+U approaches. The strong Coulomb repulsion and the spin-orbit coupling (SOC) effects on the lattice structures, electronic density of states, and band gaps are carefully studied, and compared with other A O2 (A =U , Np, Pu, and Am). The ferromagnetic configuration with half-metallic character is predicted to be energetically stable while a charge-transfer semiconductor is predicted for the antiferromagnetic configuration. The elastic constants and phonon spectra show that the fluorite structure is mechanically and dynamically stable. Based on the first-principles phonon density of states, the lattice vibrational energy is calculated using the quasiharmonic approximation. Then, the Gibbs free energy, thermal expansion coefficient, specific heat, and entropy are obtained and compared with experimental data. The mode Grüneisen parameters are presented to analyze the anharmonic properties. The Slack relation is applied to obtain the lattice thermal conductivity in temperature range of 300-1600 K. The phonon group velocities are also calculated to investigate the heat transfer. For all these properties, if available, we compare the results of CmO2 with other A O2 .

  9. Structural and optical properties of 70-keV carbon ion beam synthesized carbon nanoclusters in thermally grown silicon dioxide

    International Nuclear Information System (INIS)

    Poudel, P.R.; Poudel, P.P.; Paramo, J.A.; Strzhemechny, Y.M.; Rout, B.; McDaniel, F.D.

    2015-01-01

    The structural and optical properties of carbon nanoclusters formed in thermally grown silicon dioxide film via the ion beam synthesis process have been investigated. A low-energy (70 keV) carbon ion beam (C - ) at a fluence of 3 x 10 17 atoms/cm 2 was used for implantation into a thermally grown silicon dioxide layer (500 nm thick) on a Si (100) wafer. Several parts of the implanted samples were subsequently annealed in a gas mixture (4 % H 2 + 96 % Ar) at 900 C for different time periods. The as-implanted and annealed samples were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The carbon ion implantation depth profile was simulated using a widely used Monte Carlo-based simulation code SRIM-2012. Additionally, the elemental depth profile of the implanted carbon along with host elements of silicon and oxygen were simulated using a dynamic ion-solid interaction code T-DYN, which incorporates the effects of the surface sputtering and gradual change in the elemental composition in the implanted layers due to high-fluence ion implantation. The elemental depth profile obtained from the XPS measurements matches closely to the T-DYN predictions. Raman measurements indicate the formation of graphitic phases in the annealed samples. The graphitic peak (G-peak) was found to be increased with the annealing time duration. In the sample annealed for 10 min, the sizes of the carbon nanoclusters were found to be 1-4 nm in diameter using TEM. The PL measurements at room temperature using a 325-nm laser show broad-band emissions in the ultraviolet to visible range in the as-implanted sample. Intense narrow bands along with the broad bands were observed in the annealed samples. The defects present in the as-grown samples along with carbon ion-induced defect centers in the as-implanted samples are the main contributors to the observed

  10. Structural and optical properties of 70-keV carbon ion beam synthesized carbon nanoclusters in thermally grown silicon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Poudel, P.R. [University of North Texas, Ion Beam Modification and Analysis Laboratory, Department of Physics, Denton, TX (United States); Intel Corporation, Rio Rancho, NM (United States); Poudel, P.P. [University of Kentucky, Department of Chemistry, Lexington, KY (United States); Paramo, J.A.; Strzhemechny, Y.M. [Texas Christian University, Department of Physics and Astronomy, Fort Worth, TX (United States); Rout, B. [University of North Texas, Ion Beam Modification and Analysis Laboratory, Department of Physics, Denton, TX (United States); University of North Texas, Center for Advanced Research and Technology, Denton, TX (United States); McDaniel, F.D. [University of North Texas, Ion Beam Modification and Analysis Laboratory, Department of Physics, Denton, TX (United States)

    2014-09-18

    The structural and optical properties of carbon nanoclusters formed in thermally grown silicon dioxide film via the ion beam synthesis process have been investigated. A low-energy (70 keV) carbon ion beam (C{sup -}) at a fluence of 3 x 10{sup 17} atoms/cm{sup 2} was used for implantation into a thermally grown silicon dioxide layer (500 nm thick) on a Si (100) wafer. Several parts of the implanted samples were subsequently annealed in a gas mixture (4 % H{sub 2} + 96 % Ar) at 900 C for different time periods. The as-implanted and annealed samples were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The carbon ion implantation depth profile was simulated using a widely used Monte Carlo-based simulation code SRIM-2012. Additionally, the elemental depth profile of the implanted carbon along with host elements of silicon and oxygen were simulated using a dynamic ion-solid interaction code T-DYN, which incorporates the effects of the surface sputtering and gradual change in the elemental composition in the implanted layers due to high-fluence ion implantation. The elemental depth profile obtained from the XPS measurements matches closely to the T-DYN predictions. Raman measurements indicate the formation of graphitic phases in the annealed samples. The graphitic peak (G-peak) was found to be increased with the annealing time duration. In the sample annealed for 10 min, the sizes of the carbon nanoclusters were found to be 1-4 nm in diameter using TEM. The PL measurements at room temperature using a 325-nm laser show broad-band emissions in the ultraviolet to visible range in the as-implanted sample. Intense narrow bands along with the broad bands were observed in the annealed samples. The defects present in the as-grown samples along with carbon ion-induced defect centers in the as-implanted samples are the main

  11. Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

    Science.gov (United States)

    Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

    2015-06-16

    Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

  12. Surface structured platinum electrodes for the electrochemical reduction of carbon dioxide in imidazolium based ionic liquids.

    Science.gov (United States)

    Hanc-Scherer, Florin A; Montiel, Miguel A; Montiel, Vicente; Herrero, Enrique; Sánchez-Sánchez, Carlos M

    2015-10-07

    The direct CO2 electrochemical reduction on model platinum single crystal electrodes Pt(hkl) is studied in [C2mim(+)][NTf2(-)], a suitable room temperature ionic liquid (RTIL) medium due to its moderate viscosity, high CO2 solubility and conductivity. Single crystal electrodes represent the most convenient type of surface structured electrodes for studying the impact of RTIL ion adsorption on relevant electrocatalytic reactions, such as surface sensitive electrochemical CO2 reduction. We propose here based on cyclic voltammetry and in situ electrolysis measurements, for the first time, the formation of a stable adduct [C2mimH-CO2(-)] by a radical-radical coupling after the simultaneous reduction of CO2 and [C2mim(+)]. It means between the CO2 radical anion and the radical formed from the reduction of the cation [C2mim(+)] before forming the corresponding electrogenerated carbene. This is confirmed by the voltammetric study of a model imidazolium-2-carboxylate compound formed following the carbene pathway. The formation of that stable adduct [C2mimH-CO2(-)] blocks CO2 reduction after a single electron transfer and inhibits CO2 and imidazolium dimerization reactions. However, the electrochemical reduction of CO2 under those conditions provokes the electrochemical cathodic degradation of the imidazolium based RTIL. This important limitation in CO2 recycling by direct electrochemical reduction is overcome by adding a strong acid, [H(+)][NTf2(-)], into solution. Then, protons become preferentially adsorbed on the electrode surface by displacing the imidazolium cations and inhibiting their electrochemical reduction. This fact allows the surface sensitive electro-synthesis of HCOOH from CO2 reduction in [C2mim(+)][NTf2(-)], with Pt(110) being the most active electrode studied.

  13. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    International Nuclear Information System (INIS)

    Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

    2016-01-01

    Graphical abstract: Carbonation conversions of (a) CC, (b) CH-2, (c) CH-4, (d) CH-6, (e) CH-8 precursor adsorbents for 10 cycles. - Highlights: • Ca(OH)_2 precursor was synthesized using precipitation method. • The effect of CTAB concentration on the synthesis of Ca(OH)_2 was studied. • The sorbent synthesized using 0.8 M of CTAB showed good CO_2 adsorption capacity. • The cyclic stability of Ca(OH)_2 was increased with increase of CTAB concentration. - Abstract: Calcium hydroxide (Ca(OH)_2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)_2 based adsorbents for carbon dioxide (CO_2) capture. The effect of CTAB concentration (0.2–0.8 M) on the structure, morphology and CO_2 adsorption performance of Ca(OH)_2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG–DTA) techniques. The phase purity, crystallite size, Brunauer–Emmett–Teller (BET) surface area and CO_2 adsorption performance of Ca(OH)_2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)_2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)_2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  14. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Hlaing, Nwe Ni, E-mail: nwenihlaing76@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Vignesh, K., E-mail: vignesh134@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Anano Sphere Sdn Bhd, Lorong Industri 11, Kawasan Industri Bukit Panchor, 14300 Nibong Tebal, Penang (Malaysia); Sreekantan, Srimala, E-mail: srimala@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Pung, Swee-Yong [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Hinode, Hirofumi; Kurniawan, Winarto [Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Othman, Radzali [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Malacca (Malaysia); Thant, Aye Aye [Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Mohamed, Abdul Rahman [Low Carbon Economy (LCE) Research Group, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Salim, Chris [Department of Environmental Engineering, Surya University, Tangerang 15810, Banten (Indonesia)

    2016-02-15

    Graphical abstract: Carbonation conversions of (a) CC, (b) CH-2, (c) CH-4, (d) CH-6, (e) CH-8 precursor adsorbents for 10 cycles. - Highlights: • Ca(OH){sub 2} precursor was synthesized using precipitation method. • The effect of CTAB concentration on the synthesis of Ca(OH){sub 2} was studied. • The sorbent synthesized using 0.8 M of CTAB showed good CO{sub 2} adsorption capacity. • The cyclic stability of Ca(OH){sub 2} was increased with increase of CTAB concentration. - Abstract: Calcium hydroxide (Ca(OH){sub 2}) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH){sub 2} based adsorbents for carbon dioxide (CO{sub 2}) capture. The effect of CTAB concentration (0.2–0.8 M) on the structure, morphology and CO{sub 2} adsorption performance of Ca(OH){sub 2} was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG–DTA) techniques. The phase purity, crystallite size, Brunauer–Emmett–Teller (BET) surface area and CO{sub 2} adsorption performance of Ca(OH){sub 2} precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH){sub 2} phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH){sub 2} precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  15. Oxidation of fluoroquinolone antibiotics and structurally related amines by chlorine dioxide: Reaction kinetics, product and pathway evaluation.

    Science.gov (United States)

    Wang, Pei; He, Yi-Liang; Huang, Ching-Hua

    2010-12-01

    Fluoroquinolones (FQs) are a group of widely prescribed antibiotics and have been frequently detected in the aquatic environment. The reaction kinetics and transformation of seven FQs (ciprofloxacin (CIP), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL), lomefloxacin (LOM), pipemidic acid (PIP) and flumequine (FLU)) and three structurally related amines (1-phenylpiperazine (PP), N-phenylmorpholine (PM) and 4-phenylpiperidine (PD)) toward chlorine dioxide (ClO(2)) were investigated to elucidate the behavior of FQs during ClO(2) disinfection processes. The reaction kinetics are highly pH-dependent, can be well described by a second-order kinetic model incorporating speciation of FQs, and follow the trend of OFL > ENR > CIP ∼ NOR ∼ LOM > > PIP in reactivity. Comparison among FQs and related amines and product characterization indicate that FQs' piperazine ring is the primary reactive center toward ClO(2). ClO(2) likely attacks FQ's piperazinyl N4 atom followed by concerted fragmentation involving piperazinyl N1 atom, leading to dealkylation, hydroxylation and intramolecular ring closure at the piperazine moiety. While FQs with tertiary N4 react faster with ClO(2) than FQs with secondary N4, the overall reactivity of the piperazine moiety also depends strongly on the quinolone ring through electronic effects. The reaction rate constants obtained in clean water matrix can be used to model the decay of CIP by ClO(2) in surface water samples, but overestimate the decay in wastewater samples. Overall, transformation of FQs, particularly for those with tertiary N4 amines, could be expected under typical ClO(2) disinfection conditions. However, the transformation may not eliminate antibacterial activity because of little destruction at the quinolone ring. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Thermal, structural and electrochemical properties of new aliphatic-aromatic imine with piperazine moieties blended with titanium dioxide

    Science.gov (United States)

    Różycka, Anna; Fryń, Patryk; Iwan, Agnieszka; Bogdanowicz, Krzysztof Artur; Filapek, Michal; Górska, Natalia; Dąbczyński, Paweł; Rysz, Jakub; Pociecha, Damian; Hreniak, Agnieszka; Marzec, Monika

    2018-02-01

    A new piperazine imine, (7E)-N-((4-((E)-(4-hexadecylphenylimino)methyl)piperazin-1-yl)methylene)-4-dodecylbenzenamine, has been synthesized by the condensation of 1,4-piperazinedicarboxaldehyde with 4-hexadecylaniline. The imine was characterized by cyclic voltammetry, Fourier transform middle-infrared absorption spectroscopy and X-ray diffraction. Thermal properties of imine was analyzed by differential scanning calorimetry method during first and second heating scan at 10 and 20 °C/min. Texture of imine was investigated by polarized optical microscopy and atomic force microscopy. Furthermore, imine was blended with titanium dioxide in anatase form and fully characterized by the same methods. Piperazine imine and its mixture with titanium dioxide exhibited only a transition from crystal to isotropic state. Imine exhibits two-step reduction wave attributed to one-electron transfer in each step as was found by cyclic voltammetry. Both titanium dioxide and poly(3-hexylthiophene) change the electrochemical properties of piperazine imine, however, in different ways. Studied imine blended with titanium dioxide exhibited higher value of energy band gap than pure piperazine imine and lower Eg than pure poly(3-hexylthiophene).

  17. Titanium dioxide nanoparticles modified by salicylic acid and arginine: Structure, surface properties and photocatalytic decomposition of p-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lei [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan 030051 (China); Feng, Yujie, E-mail: yujief@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Liu, Youzhi; Wei, Bing; Guo, Jiaxin; Jiao, Weizhou [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan 030051 (China); Zhang, Zhaohan [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Zhang, Qiaoling, E-mail: zhangqiaoling@nuc.edu.cn [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan 030051 (China)

    2016-02-15

    Graphical abstract: A simple and versatile synthetic method to produce TiO{sub 2} nanoparticles surface-modified with various organic capping agents can be used for novel multifunctional photocatalysts as required for various applications in energy saving and environmental protection. - Highlights: • SA and Arg was modified through the method of dipping treatment-based on chemical adsorption in saturated solution. • Surface modified TiO{sub 2} applied in photodecomposition of nitroaromatic. • The photoreduction of nitroaromatic and photocatalytic activity under visible light irradiation were enhanced by TiO{sub 2}–SA–Arg. • TiO{sub 2}–SA–Arg showed better lipophilic, dispersion and adsorption properties. - Abstract: In this study, titanium dioxide (TiO{sub 2}) nanoparticles were surface-modified with salicylic acid (SA) and arginine (Arg) using an environmentally friendly and convenient method, and the bonding structure, surface properties and degradation efficiency of p-nitrophenol (PNP) were investigated. X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), water contact angle (WCA) measurements, ζ-potentiometric analysis, UV/visible diffuse reflectance spectroscopy (UV–vis DRS), and thermogravimetric analysis (TGA) were performed to evaluate the modification effect. The degradation rates were determined by high-performance liquid chromatography (HPLC). The results show that bidentate or bridging bonds are most likely formed between SA/Arg and TiO{sub 2} surface. Surface modification with SA, Arg, or both can improve the lipophilic properties and decrease the zeta potential, and also result in a red shift of the absorption wavelength. TiO{sub 2} nanoparticles modified by Arg or both SA and Arg show a large specific surface area and pore volume. Further, degradation

  18. Electronic structure of the actinides and their dioxides. Application to the defect formation energy and krypton solubility in uranium dioxide; Etude de la structure electronique des actinides et de leurs dioxydes. Application aux defauts ponctuels et aux gaz de fission dans le dioxyde d`uranium

    Energy Technology Data Exchange (ETDEWEB)

    Petit, T. [CEA Centre d`Etudes Nucleaires de Grenoble, 38 (France)]|[CEA Centre d`Etudes de Grenoble, 38 (France). Dept. de Thermohydraulique et de Physique

    1996-09-28

    Uranium dioxide is the standard nuclear fuel used in French h power plants. During irradiation, fission products such as krypton and xenon are created inside fuel pellets. So, gas release could become, at very high burnup, a limiting factor in the reactor exploitation. To study this subject, we have realised calculations using the Density Functional Theory (DFT) into the Local Density Approximation (LDA) and the Atomic Sphere Approximation (ASA). First, we have validated our approach by calculating cohesive properties of thorium, protactinium and uranium metals. The good agreement between our results and experimental values implies that 5f electrons are itinerant. Calculated lattice parameter, cohesive energy and bulk modulus for uranium and thorium dioxides are in very good agreement with experiment. We show that binding between uranium and oxygen atoms is not completely ionic but partially covalent. The question of the electrical conductivity still remains an open problem. We have been able to calculate punctual defect formation energies in uranium dioxide. Accordingly to experimental observations, we find that it is easier to create a defect in the oxygen sublattice than in the uranium sublattice. Finally, we have been able to predict a probable site of krypton atoms in nuclear fuel: the Schottky trio. Experiences of Extended X-ray Absorption Fine structure Spectroscopy (EXAFS) and X-ray Photoelectron Spectroscopy (XPS) on uranium dioxide doped by ionic implantation will help us in the comprehension of the studied phenomena and the interpretation of our calculations. (author). 256 refs.

  19. Titanium Dioxide Photocatalytic Polymerization of Acrylamide for Gel Electrophoresis (TIPPAGE) of Proteins and Structural Identification by Mass Spectrometry

    Science.gov (United States)

    Zhang, Wenyang; Yuan, Zhiwei; Huang, Lulu; Kang, Jie; Jiang, Ruowei; Zhong, Hongying

    2016-01-01

    Polyacrylamide gel electrophoresis (PAGE) coupled with mass spectrometry has been well established for separating, identifying and quantifying protein mixtures from cell lines, tissues or other biological samples. The copolymerization process of acrylamide and bis-acrylamide is the key to mastering this powerful technique. In general, this is a vinyl addition reaction initiated by free radical-generating reagents such as ammonium persulfate (APS) and tetramethylethylenediamine (TEMED) under basic pH and degassing experimental condition. We report herein a photocatalytic polymerization approach that is based on photo-generated hydroxyl radicals with nanoparticles of titanium dioxide. It was shown that the polymerization process is greatly accelerated in acidic condition when ultraviolet light shots on the gel solution containing TiO2 nanoparticles without degassing. This feature makes it very useful in preparing Triton X-100 acid urea (TAU) gel that has been developed for separating basic proteins such as histones and variants in acidic experimental condition. Additionally, the presence of titanium dioxide in the gel not only improves mechanistic property of gels but also changes the migration pattern of different proteins that have different affinities to titanium dioxide. PMID:26865351

  20. Carbon dioxide sensor

    Science.gov (United States)

    Dutta, Prabir K [Worthington, OH; Lee, Inhee [Columbus, OH; Akbar, Sheikh A [Hilliard, OH

    2011-11-15

    The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

  1. Formation and properties of the buried isolating silicon-dioxide layer in double-layer “porous silicon-on-insulator” structures

    Energy Technology Data Exchange (ETDEWEB)

    Bolotov, V. V.; Knyazev, E. V.; Ponomareva, I. V.; Kan, V. E., E-mail: kan@obisp.oscsbras.ru; Davletkildeev, N. A.; Ivlev, K. E.; Roslikov, V. E. [Russian Academy of Sciences, Omsk Scientific Center, Siberian Branch (Russian Federation)

    2017-01-15

    The oxidation of mesoporous silicon in a double-layer “macroporous silicon–mesoporous silicon” structure is studied. The morphology and dielectric properties of the buried insulating layer are investigated using electron microscopy, ellipsometry, and electrical measurements. Specific defects (so-called spikes) are revealed between the oxidized macropore walls in macroporous silicon and the oxidation crossing fronts in mesoporous silicon. It is found that, at an initial porosity of mesoporous silicon of 60%, three-stage thermal oxidation leads to the formation of buried silicon-dioxide layers with an electric-field breakdown strength of E{sub br} ~ 10{sup 4}–10{sup 5} V/cm. Multilayered “porous silicon-on-insulator” structures are shown to be promising for integrated chemical micro- and nanosensors.

  2. Insights into the Electronic Structure of Ozone and Sulfur Dioxide from Generalized Valence Bond Theory: Bonding in O3 and SO2.

    Science.gov (United States)

    Takeshita, Tyler Y; Lindquist, Beth A; Dunning, Thom H

    2015-07-16

    There are many well-known differences in the physical and chemical properties of ozone (O3) and sulfur dioxide (SO2). O3 has longer and weaker bonds than O2, whereas SO2 has shorter and stronger bonds than SO. The O-O2 bond is dramatically weaker than the O-SO bond, and the singlet-triplet gap in SO2 is more than double that in O3. In addition, O3 is a very reactive species, while SO2 is far less so. These disparities have been attributed to variations in the amount of diradical character in the two molecules. In this work, we use generalized valence bond (GVB) theory to characterize the electronic structure of ozone and sulfur dioxide, showing O3 does indeed possess significant diradical character, whereas SO2 is effectively a closed shell molecule. The GVB results provide critical insights into the genesis of the observed difference in these two isoelectronic species. SO2 possesses a recoupled pair bond dyad in the a"(π) system, resulting in SO double bonds. The π system of O3, on the other hand, has a lone pair on the central oxygen atom plus a pair of electrons in orbitals on the terminal oxygen atoms that give rise to a relatively weak π interaction.

  3. Effects of Combined High Hydrostatic Pressure and Dense Phase Carbon Dioxide on the Activity, Structure and Size of Polyphenoloxidase.

    Science.gov (United States)

    Duong, Trang; Balaban, Murat; Perera, Conrad

    2015-11-01

    High hydrostatic pressure (HHP) may activate undesirable enzymes such as polyphenoloxidase (PPO). Carbon dioxide (CO2 ) addition to HHP could increase enzyme inactivation. We investigated the inactivation of combined HHP and dense phase carbon dioxide process on activity, secondary conformation and size of pure PPO from mushroom. Solutions (2.35μM, in phosphate buffer pH 6.8) were treated with HHP alone (HHP), or 3.6% w/w of CO2 was injected into the package (HHP+CO2). Treatment conditions were 600 MPa, 20 °C, for 1, 3, 5, 7, and 9 min. HHP+CO2 treatment significantly decreased residual enzyme activity (REA) to 30% to 12% after 1 to 9 min, respectively, whereas only HHP had no significant effect. Both HHP and HHP+CO2 treatments caused changes in secondary conformations, however HHP+CO2 changes were more extensive. Alpha-helix fractions were reduced by 32% and 41%, while β sheet, turn and unordered increased by 63% and 213%, 100% and 71%, and 118% and 82% for HHP and HHP+CO2, respectively after 9 min. The protein size in HHP+CO2 samples was 5- to 6-fold larger than that of Control and HHP treatment, and this increase was inversely correlated with REA. The best inactivation kinetics of HHP+CO2 model was the 2-fractional model with 2 simultaneous 1st-order steps, contributing 70% and 30% to original enzyme activity, with k(labile) = 12.15 min(-1) and k(stable) = 0.07 min(-1), respectively. No recovery in activity, secondary conformation and size in all samples were observed after 1-mo storage. Addition of CO2 in HHP treatment can improve enzyme inactivation, and therefore product shelf-life and quality. High hydrostatic pressure (HHP) achieves the safety of foods as a nonthermal method, but it may activate undesirable enzymes resulting in short shelf life due to, for example flavor and color changes. Our study determined that addition of CO2 to HHP has significant effects on enzyme inactivation, secondary conformational and molecular size changes of mushroom PPO

  4. Plasticized Starch Based Bionanocomposites Containing Cellulose Nanowhiskers and Titanium Dioxide Nanoparticles: Study of Structure and Water Vapor Permeability

    Directory of Open Access Journals (Sweden)

    Nasrin Jamshidi Kaljahi

    2014-08-01

    Full Text Available The starch-based films have some disadvantages such as weak mechanical and poor water barrier properties that restrict their applications in food packaging. In the present research, to improve the properties of the starch films, a constant level of citric acid and polyvinyl alcohol (PVA (10% with different amounts of glycerol (GLY as a lubricating agent, crystal nanowhiskers (CNW and titanium dioxide (TiO2 nanoparticles were used together. Finally, the effects of these compounds on permeability properties of the obtained starch-based bionanocomposites were studied and their optimum values were determined by central composite design of response surface methodology (RSM. The results of X-Ray diffraction (XRD test showed that at low levels of TiO2 and CNW there was no diffractogram peak obtained. However, at high levels of TiO2 and CNW there emerged distinct and sharp peak which was attributed to greater crystalline region and probably non-homogeneity in particle distribution. The Fourier transmission infrared (FTIR data showed that addition of CNW and TiO2 increased hydrogen binding between the nanofillers and biopolymer matrix. The effects of TiO2 and CNW concentrations as quadratic and glycerol concentration as linear and quadratic were significant on water vapor permeability (WVP. The optimum levels of TiO2, CNW and GLY for obtaining minimum WVP corresponded to 0.118, 0.3 g and 1.06 mL, respectively.

  5. Study of a QCM Dimethyl Methylphosphonate Sensor Based on a ZnO-Modified Nanowire-Structured Manganese Dioxide Film

    Directory of Open Access Journals (Sweden)

    Guang Li

    2010-09-01

    Full Text Available Sensitive, selective and fast detection of chemical warfare agents is necessary for anti-terrorism purposes. In our search for functional materials sensitive to dimethyl methylphosphonate (DMMP, a simulant of sarin and other toxic organophosphorus compounds, we found that zinc oxide (ZnO modification potentially enhances the absorption of DMMP on a manganese dioxide (MnO2 surface. The adsorption behavior of DMMP was evaluated through the detection of tiny organophosphonate compounds with quartz crystal microbalance (QCM sensors coated with ZnO-modified MnO2 nanofibers and pure MnO2 nanofibers. Experimental results indicated that the QCM sensor coated with ZnO-modified nanostructured MnO2 film exhibited much higher sensitivity and better selectivity in comparison with the one coated with pure MnO2 nanofiber film. Therefore, the DMMP sensor developed with this composite nanostructured material should possess excellent selectivity and reasonable sensitivity towards the tiny gaseous DMMP species.

  6. The role of extra-atomic relaxation in determining Si2p binding energy shifts at silicon/silicon oxide interfaces

    International Nuclear Information System (INIS)

    Zhang, K.Z.; Greeley, J.N.; Banaszak Holl, M.M.; McFeely, F.R.

    1997-01-01

    The observed binding energy shift for silicon oxide films grown on crystalline silicon varies as a function of film thickness. The physical basis of this shift has previously been ascribed to a variety of initial state effects (Si endash O ring size, strain, stoichiometry, and crystallinity), final state effects (a variety of screening mechanisms), and extrinsic effects (charging). By constructing a structurally homogeneous silicon oxide film on silicon, initial state effects have been minimized and the magnitude of final state stabilization as a function of film thickness has been directly measured. In addition, questions regarding the charging of thin silicon oxide films on silicon have been addressed. From these studies, it is concluded that initial state effects play a negligible role in the thickness-dependent binding energy shift. For the first ∼30 Angstrom of oxide film, the thickness-dependent binding energy shift can be attributed to final state effects in the form of image charge induced stabilization. Beyond about 30 Angstrom, charging of the film occurs. copyright 1997 American Institute of Physics

  7. Thermoexpanded graphite modification by titanium dioxide

    International Nuclear Information System (INIS)

    Semko, L.S.; Gorbik, P.P.; Chujko, O.O.; Kruchek, Ya.Yi.; Dzyubenko, L.S.; Orans'ka, O.Yi.

    2006-01-01

    A method of the synthesis of thermoexpanded graphite (TEG) powders coated by titanium dioxide is developed. The conversion of n-buthylorthotitanate into TiO 2 on the TEG surface is investigated. The optimal parameters of the synthesis and the structure of titanium dioxide clusters on the TEG surface are determined

  8. Influence of antimony on the elctrochemical behaviour and the structure of the lead dioxide active mass of lead/acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Pavlov, D. (Central Lab. of Electrochemical Power Sources, Bulgarian Academy of Sciences, Sofia (Bulgaria)); Dakhouche, A. (Central Lab. of Electrochemical Power Sources, Bulgarian Academy of Sciences, Sofia (Bulgaria)); Rogachev, T. (Central Lab. of Electrochemical Power Sources, Bulgarian Academy of Sciences, Sofia (Bulgaria))

    1993-01-29

    The effect of antimony on the formation of the skeleton structure of tubular electrodes filled with lead dioxide active mass (PAM) is investigated. Antimony is added as ions to the solution, as Sb[sub 2]O[sub 3] or Sb[sub 2]O[sub 5] to PAM, or as an additive to the electrode spine alloy. The effect of antimony on the crystallinity of PAM particles and agglomerates is examined. It is established that antimony increases the capacity of tubular powder electrodes when added either to the alloy or as antimony oxide to the PAM. It accelerates the processes of formation of the PAM skeleton structure and decreases the crystallinity of PAM particles and agglomerates. These effects of antimony are explained based on the concept of a gel-crystal structure for the PAM. Antimony improves the electron conductivity of gel zones. Its effect depends on the type and valency of the antimony ions, and on the density of the PAM. (orig.)

  9. CCDC 1505386: Experimental Crystal Structure Determination : catena-[bis(mu-pyrazine)-(mu-fluoro)-(mu-oxido)-tetrafluoro-nickel-niobium carbon dioxide

    KAUST Repository

    Bhatt, Prashant

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. Structure and phase composition of the titanium dioxide thin films deposited on the surface of the metallized track membranes from polyethyleneterephthalate by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Artoshina, O.V.; Semina, V.K.; Kochnev, Yu.K.; Nechaev, A.N.; Apel', P.Yu.; Milovich, F.O.; Iskhakova, L.D.; Ermakov, R.P.; Rossouw, A.; Gorberg, B.L.

    2016-01-01

    Thin films of TiO 2 , Ag, Ag-TiO 2 , Cu-TiO 2 deposited on the surface of polyethyleneterephthalate track membranes (TM) were investigated. Metals and oxide deposition was carried out by the method of vacuum reactive sputtering with application of a planar magnetron. The microstructure of samples was studied by the scanning and transmission electron microscopy (TEM) techniques. The elemental composition of coatings was investigated using energy-dispersive spectroscopy. For the identification of phase structure, X-ray diffraction phase analysis was used at various temperatures, and the XRD crystal structure patterns of the samples were obtained by the selected area electron diffraction (SAED) in TEM analysis. It was found that titanium dioxide on the TM surface can be present in three forms: nanocrystals of tetragonal anatase with impurity of rhombic brookite and the so-called X-ray amorphous TiO 2 . Cubical Cu 2 O was identified in TM metallized by copper. Optical properties of composite membranes and films were investigated by the method of absorption spectroscopy. Calculation of energies of the direct and indirect allowed optical transitions was carried out based on the analysis of absorption spectra of the studied composite membranes. [ru

  11. Stability analysis and structural rules of titanium dioxide clusters (TiO2)n with n = 1-9

    International Nuclear Information System (INIS)

    Zhang Weiwei; Han Ye; Yao Shuyu; Sun Haiqing

    2011-01-01

    Highlights: · We investigated the structure and stability of (TiO 2 ) n clusters with n = 1-9. · Some initial structures are introduced and proved to be the real global minimum. · We summarized the structural rules for small (TiO 2 ) n clusters. · The bonding features for the energy increment or decrement of the clusters are investigated. · A general shift of stability and reactivity with size for (TiO 2 ) n clusters. - Abstract: Atomic clusters have been considered as models for fundamental mechanistic insight into complex surfaces and catalysts. The structure and stability of (TiO 2 ) n clusters with n = 1-9 are investigated using the b3lyp hybrid density functional method in this paper. Some of the clusters are proposed initially and proved to be the real global minima. The stability and band gap of the clusters as a function of size are also investigated. The structural rules of the clusters are first summarized. The lowest-lying (TiO 2 ) n isomers tend to form some compact rather than quasi-linear or circular structures. The oxygen atom in 4-fold coordination and the titanium atom in 4-fold coordination favor the cluster stability. The 5-fold coordinated Ti-atom, the Ti-Ti bond and the terminal Ti-O bond lead to stability penalty for the clusters. No evidence for a regular variation in stability or reactivity with size of the clusters has shown. The structural rules can serve as guiding factors for formation research and structure design of (TiO 2 ) n and other transition metal oxide clusters.

  12. Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, N., E-mail: necastillo@yahoo.co [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Edificio B, 04510 Mexico DF (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico); Perez, R. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Campus Morelos, 62251 Cuernavaca Morelos (Mexico); Martinez-Ortiz, M.J.; Diaz-Barriga, L. [Instituto Politecnico Nacional - ESIQIE, UPALM Edif. 7, 07738 Mexico DF (Mexico); Garcia, L. [Instituto Politecnico Nacional - ESIT, UPALM, 07738 Mexico DF (Mexico); Conde-Gallardo, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico)

    2010-04-16

    Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO{sub 2} in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO{sub 2} were prepared by wetness impregnation techniques at different concentrations of Pt and Pd {approx}1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO{sub 2} were characterized by N{sub 2} physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO{sub 2} (anatase-like structure), and the materials present tetragonal structure nanoparticles (a = 0.37842, b = 0.37842, c = 0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt{sub x}-Pd{sub (1-x)}/TiO{sub 2} based system was then conducted to study the effects of metals on the nanostructure of the materials.

  13. Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

    International Nuclear Information System (INIS)

    Castillo, N.; Perez, R.; Martinez-Ortiz, M.J.; Diaz-Barriga, L.; Garcia, L.; Conde-Gallardo, A.

    2010-01-01

    Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO 2 in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO 2 were prepared by wetness impregnation techniques at different concentrations of Pt and Pd ∼1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO 2 were characterized by N 2 physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO 2 (anatase-like structure), and the materials present tetragonal structure nanoparticles (a = 0.37842, b = 0.37842, c = 0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt x -Pd (1-x) /TiO 2 based system was then conducted to study the effects of metals on the nanostructure of the materials.

  14. Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

    DEFF Research Database (Denmark)

    Wang, Xiaoliang; Zhao, Yanyan; Mølhave, Kristian

    2017-01-01

    advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO₂ micro and nano structures, and present the principles and growth mechanisms of TiO₂ nanostructures via different strategies...

  15. Electronic structure and core-level spectra of light actinide dioxides in the dynamical mean-field theory

    Czech Academy of Sciences Publication Activity Database

    Kolorenč, Jindřich; Shick, Alexander; Lichtenstein, A.I.

    2015-01-01

    Roč. 92, č. 8 (2015), "085125-1"-"085125-10" ISSN 1098-0121 R&D Projects: GA ČR GC15-05872J Institutional support: RVO:68378271 Keywords : electronic-structure calculations * dynamical mean-field theory * Mott insulators * actinides * oxides * photoemission Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

  16. Influence of structure of carrier (silica gel) on texture and catalytic properties of vanadium catalysts for sulfur dioxide oxidation

    International Nuclear Information System (INIS)

    Simonova, L.G.; Fenelonov, V.B.; Dzis'ko, V.A.; Noskova, S.P.; Kryukova, G.N.; Litvak, G.S.

    1982-01-01

    The influence of initial porous structure of a carrier-silica gel on texture and catalytic properties of vanadium catalysts is considered. It is shown that low thermal stability of the carrier results not only in considerable decrease of the catalyst surface during heat treatment but also in blocking part of active component in locked pores which accounts for the activity decrease in kinetic region and formation of active component forms that can not be extracted by acid

  17. Effects of ablation energy and post-irradiation on the structure and properties of titanium dioxide nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Guillén, G. García [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León, México (Mexico); Palma, M. I. Mendivil [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León, México (Mexico); Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455, México (Mexico); and others

    2017-05-31

    Highlights: • Highlights • TiO{sub 2} nanomaterials were prepared by PLALM. • Characterized these nanomaterials using TEM, XPS, XRD, optical and luminescence measurements. • Morphology of these nanomaterials were dependent on ablation wavelength, fluence and post-irradiation time. • Laser post irradiation modified the size, morphology and structure of these TiO{sub 2} nanomaterials. - Abstract: Nanomaterials of titanium oxide were prepared by pulsed laser ablation of a titanium metal target in distilled water. The ablation was performed at different laser energy (fluence) using a nanosecond pulsed Nd:YAG laser output of 1064 and 532 nm. A post-irradiation of titanium oxide nanocolloids obtained by ablation using 532 nm was carried out to explore its effects on the structure and properties. Analysis of morphology, crystalline phase, elemental composition, chemical state, optical and luminescent properties were performed using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), UV–-vis absorption spectroscopy and room temperature photoluminescence spectroscopy. It was found that titanium oxide nanomaterial morphologies and optical properties were determined by ablation wavelength and fluence. Further, nanocolloids prepared by 532 nm ablation showed a crystalline phase change by laser post-irradiation. The results showed that pulsed laser ablation in liquid as well as post-irradiation were effective in modifying the final structure and properties of titanium oxide nanocolloids.

  18. Effects of ablation energy and post-irradiation on the structure and properties of titanium dioxide nanomaterials

    International Nuclear Information System (INIS)

    Guillén, G. García; Shaji, S.; Palma, M. I. Mendivil; Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das

    2017-01-01

    Highlights: • Highlights • TiO_2 nanomaterials were prepared by PLALM. • Characterized these nanomaterials using TEM, XPS, XRD, optical and luminescence measurements. • Morphology of these nanomaterials were dependent on ablation wavelength, fluence and post-irradiation time. • Laser post irradiation modified the size, morphology and structure of these TiO_2 nanomaterials. - Abstract: Nanomaterials of titanium oxide were prepared by pulsed laser ablation of a titanium metal target in distilled water. The ablation was performed at different laser energy (fluence) using a nanosecond pulsed Nd:YAG laser output of 1064 and 532 nm. A post-irradiation of titanium oxide nanocolloids obtained by ablation using 532 nm was carried out to explore its effects on the structure and properties. Analysis of morphology, crystalline phase, elemental composition, chemical state, optical and luminescent properties were performed using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), UV–-vis absorption spectroscopy and room temperature photoluminescence spectroscopy. It was found that titanium oxide nanomaterial morphologies and optical properties were determined by ablation wavelength and fluence. Further, nanocolloids prepared by 532 nm ablation showed a crystalline phase change by laser post-irradiation. The results showed that pulsed laser ablation in liquid as well as post-irradiation were effective in modifying the final structure and properties of titanium oxide nanocolloids.

  19. Hybrid-DFT  +  V w method for band structure calculation of semiconducting transition metal compounds: the case of cerium dioxide.

    Science.gov (United States)

    Ivády, Viktor; Gali, Adam; Abrikosov, Igor A

    2017-11-15

    Hybrid functionals' non-local exchange-correlation potential contains a derivative discontinuity that improves on standard semi-local density functional theory (DFT) band gaps. Moreover, by careful parameterization, hybrid functionals can provide self-interaction reduced description of selected states. On the other hand, the uniform description of all the electronic states of a given system is a known drawback of these functionals that causes varying accuracy in the description of states with different degrees of localization. This limitation can be remedied by the orbital dependent exact exchange extension of hybrid functionals; the hybrid-DFT  +  V w method (Ivády et al 2014 Phys. Rev. B 90 035146). Based on the analogy of quasi-particle equations and hybrid-DFT single particle equations, here we demonstrate that parameters of hybrid-DFT  +  V w functional can be determined from approximate theoretical quasi-particle spectra without any fitting to experiment. The proposed method is illustrated on the charge self-consistent electronic structure calculation for cerium dioxide where itinerant valence states interact with well-localized 4f atomic like states, making this system challenging for conventional methods, either hybrid-DFT or LDA  +  U, and therefore allowing for a demonstration of the advantages of the proposed scheme.

  20. Erosion of common structural materials and the degradation of suspended particles in flowing suspension of graphite powder in carbon dioxide gas

    International Nuclear Information System (INIS)

    Garton, D.A.; Hawes, R.I.; Rose, P.W.

    1968-06-01

    Experiments have been performed to examine the erosion of common materials of construction by a flowing suspension of graphite powder in carbon dioxide gas and the degradation of the graphite powder in the suspension. The suspension was circulated through a stainless steel loop at a pressure of 200 p.s.i.g. and bulk fluid temperature of 100-150 deg. C. No change in the weight of pins of mild steel, stainless steel and zircaloy, which were placed across the flow stream in a region where the velocity approached 100 ft./sec, could be detected after 350 hours of circulation. Examination of micro-photographs of the cross sections of the specimens showed no change in the structure of the metals. Considerable erosion of graphite pins producing a 6% decrease in the weight was observed under similar conditions. Detailed spectrographic analysis of the suspended powder taken at various times during the experiment showed no noticeable increase in the impurity content which could be attributed to erosion of the test specimens. A considerable increase in the tungsten, tin and cobalt concentration was observed and this is attributed to wear of the pump seal surfaces. The mean particle size of the suspended graphite powder was observed to decrease rapidly from 5 microns to 3 microns after only a few hours of circulation in the loop. After this initial period there was little further change in the particle size, the mean diameter being 2.85 microns after 167 hours of circulation. (author)

  1. Molecular structure and infrared spectra of the monomeric 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (methyl pseudosaccharyl ether)

    Science.gov (United States)

    Kaczor, Agnieszka; Almeida, Rui; Gómez-Zavaglia, Andrea; Cristiano, Maria de Lurdes S.; Fausto, Rui

    2008-03-01

    The computational description of saccharin (1,2-benzisothiazol-3(2 H)-one-1,1-dioxide) and its derivatives is difficult due to the presence of hypervalent S dbnd O bonds in their structures. Therefore, in this investigation, the HF, DFT/B3LYP and MP2 methods were used to predict the geometry and the infrared spectrum of the saccharyl derivative 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (MBID). Their relative predictive capabilities were then evaluated by comparing the obtained results with experimentally available data, namely the newly obtained IR spectra of MBID isolated in low-temperature inert matrices. For each method, different basis sets [6-31++G(d,p), 6-31++G(3df,3pd), 6-311++G(d,p), 6-311++G(2df,2pd), 6-311++G(3df,3pd), aug-cc-pVDZ and aug-cc-pVTZ] were considered. The best overall agreement has been achieved at the B3LYP/6-311++G(3df,3pd) and B3LYP/6-31++G(3df,3pd) levels of theory, showing the adequacy of the B3LYP functional to describe the investigated properties in this type of compounds and stressing the relevance of including high-order polarization functions in the basis set. The chosen level of theory [B3LYP/6-311++G(3df,3pd)] was applied to analyze the vibrational spectra and the geometry of the title molecule. In agreement with the experiment, the C sbnd O sbnd C linkage in MBID is predicted by these calculations to exhibit considerably short (1.320 Å) and long (1.442 Å) (N dbnd )C sbnd O and (H 3)C sbnd O bonds, respectively, and a hybridization of the central oxygen atom close to sp 2 (the C sbnd O sbnd C angle is predicted to be ca. 117°). This C sbnd O sbnd C bonding pattern fits the well-known high reactivity of MBID upon thermal rearrangement, which has been shown to result in easy selective [1,3']-isomerization of the compound.

  2. Microlith-based Structured Sorbent for Carbon Dioxide, Humidity, and Trace Contaminant Control in Manned Space Habitats

    Science.gov (United States)

    Junaedi, Christian; Roychoudhury, SUbir; Howard, David F.; Perry, Jay L.; Knox, James C.

    2011-01-01

    To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.

  3. Optical and structural characterization od titanium dioxide films used for construction of dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Ivanovska, Tanja

    2012-01-01

    The dye-sensitized solar cells are the most serious concept that could replace the silicon solar cells. These are low-cost photovoltaic, and represent a technology which could seriously decrease the cost of the electrical energy they produce. The dye-sensitized solar cells are composed of several layers of materials that belong to the group of inorganic semiconductors. For the efficiency improvement of these cells, there are two basic concepts of research regarding the construction materials. On one side, investigation of new materials that will, as a result of their physical and electrochemical characteristics, increase the cell efficiency, and on the other side, use of materials that will contribute to the long term stability of the cell in atmospheric conditions. As a part of this Master thesis, compact and meso porous Ti(>2 films for dye- sensitized solar cells have been prepared. The compact Ti0 2 films were deposited with the technique of spray pyrolysis, and the preparation of the meso porous films was made with a blade casting technique. The optical and structural analysis and characterization of the films was done with optical spectroscopy in the visible and ultraviolet spectral region (UV- Vis), Raman spectroscopy and atomic force microscopy (AFM). The crystal structure of the films, surface uniformity, thickness and grain size dependence on the deposition parameters was investigated, this led to calculation of the optical constants for the compact films, as well as the determination of the electron transitions and the determination of the bang gap energy. Also regarding the structure and porosity of the meso porous films, characterization of the quality of the film depending on the chemical composition of the paste used for deposition was made. As a result of the preformed investigations, through defining the structural and optical parameters of quality compact and meso porous TiC>2 films for dye-sensitized solar cells, the optimal parameters for film

  4. Growth and structure of titanium dioxide on the transition metal surfaces Re(10-10) and Ru(0001); Wachstum und Struktur von Titandioxid auf den Uebergangsmetalloberflaechen Re(10-10) und Ru(0001)

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, D.

    2007-03-15

    In this work, we studied the growth and structure of titanium dioxide films on two morphologically different transition metal surfaces, namely the trench-like rhenium(10-10) and the hexagonal ruthenium(0001). The following methods were used: X-ray photoelectron and Auger-electron spectroscopy (XPS and AES), low energy electron diffraction (LEED), low energy Helium-ion scattering (LEIS), scanning tunneling microscopy (STM) and X-ray diffraction (XRD). Titanium dioxide films on rhenium(10-10) were synthesized by co-adsorption of titanium vapor in an oxygen atmosphere up to a thickness of 500 Aa and investigated by means of LEED, LEIS, XPS and XRD. In order to calibrate the titanium flux, the growth mode of titanium on the Re(10-10) surface was determined by means of LEIS, XPS and LEED. The growth of titanium dioxide on the hexagonal ruthenium(0001) surface was investigated by means of STM, XPS and AES. Due to the alloying affinity of Ti and Ru, a titanium oxide film pre-grown at low temperature was finally/fully oxidized at elevated temperature and pressure. First experiments concerning the growth of gold on these titanium dioxide films are presented. One important result of the ongoing work is the imaging of gold clusters with 2-5 atoms in the troughs of rutile(110) beside the typically observed clusters with 3 nm diameter by STM. (orig.)

  5. Investigating the structural changes of uranium dioxide dependent on additives, Phase I - Uranium-oxide system from structural-phase aspect; Ispitivanje strukturnih promena kod urandioksida u zavisnosti od aditiva, I faza - Sistem Uran-kiseonik sa strukturno-faznog aspekta

    Energy Technology Data Exchange (ETDEWEB)

    Manojlovic, Lj [Institute of Nuclear Sciences Boris Kidric, Laboratorija za reaktorske materijale, Vinca, Beograd (Serbia and Montenegro)

    1962-12-15

    Having in mind the complex structure of the system uranium-oxygen, and that experimental studies of this system lead to controversial conclusions, an extensive review and analysis of the papers published on this subject were needed. This review wold be very useful for interpreting the expected structural changes of the uranium dioxide dependent on the additives.

  6. The influence of hydrostatic pressure on the electronic structure and optical properties of tin dioxide: A first-principle study

    International Nuclear Information System (INIS)

    Cai Lugang; Liu Famin; Zhang Dian; Zhong Wenwu

    2013-01-01

    The evolutions of electronic structure and optical properties of SnO 2 under hydrostatic pressure are studied theoretically using first-principle calculations. The calculation results show that the energy band gap of SnO 2 expands with increasing pressure, and the relationship between them can be fitted well by a second order polynomial expression. The complex dielectric functions are calculated and it is found that its imaginary part moves to higher photon energy levels with increasing pressure; meanwhile the static dielectric function constant decreases correspondingly. The dependences of other optical properties, such as the reflectivity spectra and loss function, on the hydrostatic pressure are also calculated and obtained, and the relationships between the optical properties and hydrostatic pressure are discussed and analyzed.

  7. Influence of Pd Layer on the Sensitivity of CHx/PS/Si as Structure for Oxygen Sensing

    Directory of Open Access Journals (Sweden)

    N. Ghellai

    2008-04-01

    Full Text Available It has been demonstrated recently that the fabricated gas sensing device based on hydrocarbons (CHx/Porous silicon structure can be used for detecting a low concentration of a large variety of gases but does not respond to oxygen. In this work, an oxygen sensor based on Palladium/hydrocarbons (CHx/ Porous silicon/ Silicon structure has been studied in presence of oxygen gas. Current-voltage and capacitance-voltage characterizations show that Pd/CHx-PS/Si structure is very sensitive toward O2 gas. A fast response time of the sensor of about 3 s is measured.

  8. Structural in situ study of the thermal behavior of manganese dioxide materials: toward selected electrode materials for supercapacitors.

    Science.gov (United States)

    Ghodbane, Ouassim; Pascal, Jean-Louis; Fraisse, Bernard; Favier, Frédéric

    2010-12-01

    The thermal behavior of a series of MnO2 materials was investigated toward MnO2 microstructures under inert atmospheres. The byproduct formed during MnO2 heat treatments from the room temperature to 800 °C were characterized by in situ X-ray diffraction analyses. It was found that annealing spinel and ramsdellite phases caused the formation of MnO2 pyrolusite at 200 °C, Mn2O3, at 400 °C, and then Mn3O4 at higher temperatures. In the case of cryptomelane and birnessite phases, the heating process resulted in the formation of K0.51Mn0.93O2 at 600 °C, while Mn3O4 was also formed and still present up to 800 °C. Heat-treating Ni-todorokite and OMS-5 up to about 450 °C led to the formation of NiMn2O4 and NaxMnO2, respectively, and again Mn3O4 at higher temperatures. All of these structural transformations were correlated to resulting weight losses of MnO2 powders, measured by thermogravimetric analyses, during the heating process. Cyclic voltammetry measurements were performed in the presence of 0.5 M K2SO4 aqueous solution for annealed cryptomelane, K0.51Mn0.93O2, and Mn3O4-based electrodes. It was found that MnO2 cryptomelane is electrochemically stable upon heating. The long-term charge/discharge voltammetric cycling revealed that the specific capacitance of Mn3O4-based electrode is significantly improved from 14 F·g(-1) (after 20 cycles) to 123 F·g(-1) (after 500 cycles).

  9. Anatase titanium dioxide nanoparticles in mice: evidence for induced structural and functional sperm defects after short-, but not long-, term exposure

    Directory of Open Access Journals (Sweden)

    Michelle A Smith

    2015-04-01

    Full Text Available Titanium dioxide (TiO 2 nanoparticles (TNPs are widely used commercially and exist in a variety of products. To determine if anatase TNPs (ATNPs in doses smaller than previously used reach the scrotum after entry in the body at a distant location and induce sperm defects, 100% ATNP (2.5 or 5 mg kg−1 body weight was administered intraperitoneally to adult males for three consecutive days, followed by sacrifice 1, 2, 3, or 5 weeks later (long- or 24, 48 or 120 h (short-term exposure. Transmission electron microscopy revealed the presence of ANTP in scrotal adipose tissues collected 120 h postinjection when cytokine evaluation showed an inflammatory response in epididymal tissues and fluid. At 120 h and up to 3 weeks postinjection, testicular histology revealed enlarged interstitial spaces. Significantly increased numbers of terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling-positive (apoptotic germ (P = 0.002 and interstitial space cells (P = 0.04 were detected in treated males. Caudal epididymal sperm from the short-term, but not a long-term, arm showed significantly (P < 0.001 increased frequencies of flagellar abnormalities, excess residual cytoplasm (ERC, and unreacted acrosomes in treated versus controls (dose-response relationship. A novel correlation between ERC and unreacted acrosomes was uncovered. At 120 h, there were significant decreases in hyperactivated motility (P < 0.001 and mitochondrial membrane potential (P < 0.05, and increased reactive oxygen species levels (P < 0.00001 in treated versus control sperm. These results indicate that at 4-8 days postinjection, ANTP induce structural and functional sperm defects associated with infertility, and DNA damage via oxidative stress. Sperm defects were transient as they were not detected 10 days to 5 weeks postinjection.

  10. Anatase titanium dioxide nanoparticles in mice: evidence for induced structural and functional sperm defects after short-, but not long-, term exposure

    Science.gov (United States)

    Smith, Michelle A; Michael, Rowan; Aravindan, Rolands G; Dash, Soma; Shah, Syed I; Galileo, Deni S; Martin-DeLeon, Patricia A

    2015-01-01

    Titanium dioxide (TiO2) nanoparticles (TNPs) are widely used commercially and exist in a variety of products. To determine if anatase TNPs (ATNPs) in doses smaller than previously used reach the scrotum after entry in the body at a distant location and induce sperm defects, 100% ATNP (2.5 or 5 mg kg−1 body weight) was administered intraperitoneally to adult males for three consecutive days, followed by sacrifice 1, 2, 3, or 5 weeks later (long-) or 24, 48 or 120 h (short-term exposure). Transmission electron microscopy revealed the presence of ANTP in scrotal adipose tissues collected 120 h postinjection when cytokine evaluation showed an inflammatory response in epididymal tissues and fluid. At 120 h and up to 3 weeks postinjection, testicular histology revealed enlarged interstitial spaces. Significantly increased numbers of terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling-positive (apoptotic) germ (P = 0.002) and interstitial space cells (P = 0.04) were detected in treated males. Caudal epididymal sperm from the short-term, but not a long-term, arm showed significantly (P < 0.001) increased frequencies of flagellar abnormalities, excess residual cytoplasm (ERC), and unreacted acrosomes in treated versus controls (dose-response relationship). A novel correlation between ERC and unreacted acrosomes was uncovered. At 120 h, there were significant decreases in hyperactivated motility (P < 0.001) and mitochondrial membrane potential (P < 0.05), and increased reactive oxygen species levels (P < 0.00001) in treated versus control sperm. These results indicate that at 4–8 days postinjection, ANTP induce structural and functional sperm defects associated with infertility, and DNA damage via oxidative stress. Sperm defects were transient as they were not detected 10 days to 5 weeks postinjection. PMID:25370207

  11. Carbon dioxide as chemical feedstock

    National Research Council Canada - National Science Library

    Aresta, M

    2010-01-01

    ... Dioxide as an Inert Solvent for Chemical Syntheses 15 Alessandro Galia and Giuseppe Filardo Introduction 15 Dense Carbon Dioxide as Solvent Medium for Chemical Processes 15 Enzymatic Catalysis in Dense Carbon Dioxide 18 Other Reactions in Dense Carbon Dioxide 19 Polymer Synthesis in Supercritical Carbon Dioxide 20 Chain Polymerizations: Synt...

  12. Muon transfer to sulphur dioxide

    International Nuclear Information System (INIS)

    Mulhauser, F.; Schneuwly, H.

    1993-01-01

    A systematic study of muon capture and muon transfer has been performed in seven different H 2 + SO 2 gas mixtures. From the single-exponential time structure of the muonic sulphur x-rays, one determines the lifetime of the μp atoms under the given experimental conditions. The reduced muon transfer rates to the sulphur dioxide molecule, deduced from these lifetimes, all agree well with each other. The muonic oxygen time spectra show an additional structure as if μp atoms of another kind were present. Comparable time structures are observed in a D 2 + SO 2 mixture. (author)

  13. Influence of the incorporation of titanium dioxide (TiO{sub 2}) on the morphological, structural and electrical properties of Graphene oxide (GO) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Viana Junior, Emilson Ribeiro; Wegher, Gustavo; Deus, Jeferson Ferreira de, E-mail: emilsonjunior@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UFTPR), Curitiba (Brazil)

    2016-07-01

    Full text: Carbon based nanostructures, as Carbon Nanotubes (CNT), Graphene (G) and Graphene Oxide (GO) have been extensively studied in the last years due to their unique electrical and optical properties. Recent research show that graphene can be used to improve the dispersion and stabilization of metal and metal-oxide nanostructures. Titanium dioxide (TiO{sub 2}) has been studied due to its non-toxicity, chemical stability and optoelectronic properties. However, the recombination of photoinduced electrons and holes limits its use on optoelectronic devices. To improve the charge separation efficiency of TiO{sub 2}, much effort has been focused on TiO{sub 2} nanocomposites. In this work, thin films devices of GO and Graphene Oxide with TiO{sub 2} (GO-TiO{sub 2}) were prepared using an alternative chemical route based on the Hummer’s method. The morphology and crystalline structure of the GO and GO with TiO{sub 2} thin films was investigated by X-ray power diffraction (XRD) and scanning electron microscopy (SEM). Was found that the anatase TiO{sub 2} TF were incorporated on the GO structure. Ultraviolet-visible spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FTIR) were also performed in order to corroborate with the results of XRD and SEM obtained. The electrical characterization of the GO and GO-TiO{sub 2} TF were performed using the four-probe van der Pauw method. The resistivity, density and the mobility of the carriers in the TFs were determined as a function of temperature. It was found that the electrical resistivity, the concentration of the free-carriers, the activation energy, and the capacitance of the device decrease due to the incorporation of TiO{sub 2} on GO, but the mobility increases. Due to low values of the activation energy the density of carriers thermally induced was high enough that lead to a metal-to insulator transition near room temperature. The ratio TiO{sub 2}:GO will be studied, in order to provide the best

  14. Manufacturing sector carbon dioxide emissions in nine OECD countries 1973--87: A Divisia index decomposition to changes in fuel mix, emission coefficients, industry structure, energy intensities, and international structure

    International Nuclear Information System (INIS)

    Torvanger, A.

    1990-11-01

    In this paper the reduction in energy-related manufacturing carbon dioxide emissions for nine OECD countries in the period 1973 to 1987 is analyzed. Carbon dioxide emissions are estimated from energy use data. The emphasis is on carbon dioxide intensities, defined as emissions divided by value added. The overall manufacturing carbon dioxide intensity for the nine OECD countries was reduced by 42% in the period 1973--1987. Five fuels are specified together with six subsectors of manufacturing. Carbon dioxide emissions are estimated from fossil fuel consumption, employing emissions coefficients for gas, oil and solids. In addition, electricity consumption is specified. For electricity use an emission coefficient index is calculated from the shares of fossil fuels, nuclear power and hydro power used to generate electricity, and the efficiency in electricity generation from these energy sources. A Divisia index approach is used to sort out the contribution to reduced carbon dioxide intensity from different components. The major finding is that the main contribution to reduced carbon dioxide intensity is from the general reduction in manufacturing energy intensity, most likely driven by economic growth and increased energy prices, giving incentives to invest in new technology and new industrial processes. There is also a significant contribution from reduced production in the most carbon dioxide intensive subsectors, and a contribution from higher efficiency in electricity generation together with a larger nuclear power share at the expense of oil. 19 refs., 5 figs., 11 tabs

  15. Molecular Dynamics Simulation of Carbon Dioxide in Single-Walled Carbon Nanotubes in the Presence of Water: Structure and Diffusion Studies

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Martin; Brennan, J. K.; Lísal, Martin

    2015-01-01

    Roč. 113, 9-10 (2015), s. 1124-1136 ISSN 0026-8976 R&D Projects: GA ČR(CZ) GA13-02938S Institutional support: RVO:67985858 Keywords : carbon dioxide separation * density profiles * self-diffusion coefficients Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.837, year: 2015

  16. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1979-01-01

    Sintered uranium dioxide pellets composed of particles of size > 50 microns suitable for power reactor use are made by incorporating a small amount of sulphur into the uranium dioxide before sintering. The increase in grain size achieved results in an improvement in overall efficiency when such pellets are used in a power reactor. (author)

  17. Classification of titanium dioxide

    International Nuclear Information System (INIS)

    Macias B, L.R.; Garcia C, R.M.; Maya M, M.E.; Ita T, A. De; Palacios G, J.

    2002-01-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO 2 . The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  18. More bad news about carbon dioxide emissions

    International Nuclear Information System (INIS)

    Stonehouse, D.

    2000-01-01

    The affect that increased carbon dioxide concentrations has on plants and animals was discussed. Most research focuses on the impacts that carbon dioxide concentrations has on climatic change. Recent studies, however, have shown that elevated levels of carbon dioxide in the atmosphere caused by burning fossils fuels changes the chemical structure of plants and could lead to significant disruptions in ecological food chains. High carbon dioxide levels cause plants to speed up photosynthesis, take in the gas, and use the carbon to produce more fibre and starch while giving off oxygen as a byproduct. As plants produce more carbon, their levels of nitrogen diminish making them less nutritious for the insects and animals that feed on them. This has serious implications for farmers, as pests would have to eat more of their crops to survive. In addition, farmers would have to supplement livestock with nutrients

  19. Internal friction in uranium dioxide

    International Nuclear Information System (INIS)

    Paulin Filho, Pedro Iris

    1979-01-01

    The uranium dioxide inelastic properties were studied measuring internal friction at low frequencies (of the order of 1 Hz). The work was developed in the 160 to 400 deg C temperature range. The effect of stoichiometry variation was studied oxidizing the sample with consequent change of the defect structure originally present in the non-stoichiometric uranium dioxide. The presence of a wide and irregular peak due to oxidation was observed at low temperatures. Activation energy calculations indicated the occurrence of various relaxation processes and assuming the existence of a peak between - 80 and - 70 deg C , the absolute value obtained for the activation energy (0,54 eV) is consistent with the observed values determined at medium and high frequencies for the stress induced reorientation of defects. The microstructure effect on the inelastic properties was studied for stoichiometric uranium dioxide, by varying grain size and porosity. These parameters have influence on the high temperature measurements of internal friction. The internal friction variation for temperatures higher than 340 deg C is thought to be due to grain boundary relaxation phenomena. (author)

  20. Report of the Carbon Dioxide Committee II

    International Nuclear Information System (INIS)

    1994-01-01

    The Carbon Dioxide Committee was given the task of preparing a suggestion of the acts aimed at reducing the greenhouse gas emissions and increasing the sinks of carbon in Finland. Emissions of all greenhouse gases were in 1990 80 million tons. calculated as carbon dioxide. The carbon dioxide emissions were about 58 million tons of the total. The increase of forest resources binds carbon from the atmosphere and reduces thereby net emissions of Finland at present by nearly 30 million tons of carbon dioxide. Carbon dioxide emissions will grow during the next decades, unless strong measures to control them will not be taken. As a result of the Commissions examination, acts will be needed both in the production of energy and in its consumption. Emissions can be reduced by replacing fossil fuels with nuclear energy, bioenergy and other renewable energy sources. Saving of energy and improvement of energy efficiency will limit carbon dioxide emissions. The Commission has made suggestions both to change the structure of energy production and to control the consumption of energy. (orig.)

  1. Uranium dioxide. Sintering test

    International Nuclear Information System (INIS)

    Anon.

    Description of a sintering method and of the equipment devoted to uranium dioxide powder caracterization and comparison between different samples. Determination of the curve giving specific volume versus pressure and micrographic examination of a pellet at medium pressure [fr

  2. Carbon dioxide absorbent and method of using the same

    Science.gov (United States)

    Perry, Robert James; O'Brien, Michael Joseph

    2014-06-10

    In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.

  3. Carbon dioxide absorbent and method of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Robert James; O' Brien, Michael Joseph

    2015-12-29

    In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.

  4. IMPEDANCE SPECTROSCOPY OF POLYCRYSTALLINE TIN DIOXIDE FILMS

    Directory of Open Access Journals (Sweden)

    D. V. Adamchuck

    2016-01-01

    Full Text Available The aim of this work is the analysis of the influence of annealing in an inert atmosphere on the electrical properties and structure of non-stoichiometric tin dioxide films by means of impedance spectroscopy method. Non-stoichiometric tin dioxide films were fabricated by two-step oxidation of metallic tin deposited on the polycrystalline Al2O3 substrates by DC magnetron sputtering. In order to modify the structure and stoichiometric composition, the films were subjected to the high temperature annealing in argon atmosphere in temperature range 300–800 °С. AC-conductivity measurements of the films in the frequency range 20 Hz – 2 MHz were carried out. Variation in the frequency dependencies of the real and imaginary parts of the impedance of tin dioxide films was found to occur as a result of high-temperature annealing. Equivalent circuits for describing the properties of films with various structure and stoichiometric composition were proposed. Possibility of conductivity variation of the polycrystalline tin dioxide films as a result of аnnealing in an inert atmosphere was demonstrated by utilizing impedance spectroscopy. Annealing induces the recrystallization of the films, changing in their stoichiometry as well as increase of the sizes of SnO2 crystallites. Variation of electrical conductivity and structure of tin dioxide films as a result of annealing in inert atmosphere was confirmed by X-ray diffraction analysis. Analysis of the impedance diagrams of tin dioxide films was found to be a powerful tool to study their electrical properties. 

  5. Coupling of Carbon Dioxide with Epoxides Efficiently Catalyzed by Thioether-Triphenolate Bimetallic Iron(III) Complexes: Catalyst Structure-Reactivity Relationship and Mechanistic DFT Study

    KAUST Repository

    Della Monica, Francesco; Vummaleti, Sai V. C.; Buonerba, Antonio; Nisi, Assunta De; Monari, Magda; Milione, Stefano; Grassi, Alfonso; Cavallo, Luigi; Capacchione, Carmine

    2016-01-01

    A series of dinuclear iron(III)I complexes supported by thioether-triphenolate ligands have been prepared to attain highly Lewis acidic catalysts. In combination with tetrabutylammonium bromide (TBAB) they are highly active catalysts in the synthesis of cyclic organic carbonates through the coupling of carbon dioxide to epoxides with the highest initial turnover frequencies reported to date for the conversion of propylene oxide to propylene carbonate for iron-based catalysts (5200h-1; 120°C, 2MPa, 1h). In particular, these complexes are shown to be highly selective catalysts for the coupling of carbon dioxide to internal oxiranes affording the corresponding cyclic carbonates in good yield and with retention of the initial stereochemical configuration. A density functional theory (DFT) investigation provides a rational for the relative high activity found for these Fe(III) complexes, showing the fundamental role of the hemilabile sulfur atom in the ligand skeleton to promote reactivity. Notably, in spite of the dinuclear nature of the catalyst precursor only one metal center is involved in the catalytic cycle. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Coupling of Carbon Dioxide with Epoxides Efficiently Catalyzed by Thioether-Triphenolate Bimetallic Iron(III) Complexes: Catalyst Structure-Reactivity Relationship and Mechanistic DFT Study

    KAUST Repository

    Della Monica, Francesco

    2016-08-25

    A series of dinuclear iron(III)I complexes supported by thioether-triphenolate ligands have been prepared to attain highly Lewis acidic catalysts. In combination with tetrabutylammonium bromide (TBAB) they are highly active catalysts in the synthesis of cyclic organic carbonates through the coupling of carbon dioxide to epoxides with the highest initial turnover frequencies reported to date for the conversion of propylene oxide to propylene carbonate for iron-based catalysts (5200h-1; 120°C, 2MPa, 1h). In particular, these complexes are shown to be highly selective catalysts for the coupling of carbon dioxide to internal oxiranes affording the corresponding cyclic carbonates in good yield and with retention of the initial stereochemical configuration. A density functional theory (DFT) investigation provides a rational for the relative high activity found for these Fe(III) complexes, showing the fundamental role of the hemilabile sulfur atom in the ligand skeleton to promote reactivity. Notably, in spite of the dinuclear nature of the catalyst precursor only one metal center is involved in the catalytic cycle. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Substituent influence on the structural, vibrational and electronic properties of 2,5-dihydrothiophene-1,1-dioxide by experimental and DFT methods.

    Science.gov (United States)

    Arjunan, V; Thirunarayanan, S; Durga Devi, G; Mohan, S

    2015-11-05

    Spectroscopic and theoretical quantum chemical studies of 2,5-dihydrothiophene-1,1-dioxide and 3-methyl-2,5-dihydrothiophene-1,1-dioxide have been carried out by FTIR and FT-Raman spectral techniques along with B3LYP methods. The geometry of the compounds have been optimised by B3LYP method with 6-311++G(∗∗) and cc-pVTZ basis sets. The geometrical parameters obtained at B3LYP levels have been compared with the experimental values. Molecular electrostatic potential surface, total electron density distribution and frontier molecular orbital are constructed at B3LYP/cc-pVTZ level to understand the electronic properties. The charge density distribution and sites of chemical reactivity of the molecules have been obtained by mapping electron density isosurface with electrostatic potential surfaces. Natural bond orbital analysis of the molecules are carried out and the occupancies and the atomic hybrid contributions are calculated. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Morphological and structural evolution of the anatase phase of silicon modified titanium dioxide obtained by Sol-gel; Evolucao estrutural e morfologica da fase anatase de dioxido de titanio modificada com silicio obtido pelo Metodo Sol-Gel

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, S.A.; Oliveira, C.T.; Ciola, R.A.; Cavalheiro, A.A., E-mail: silvanicelopes@gmail.com [Universidade Estadual de Mato Grosso do Sul (CPTREN/UEMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    The photonic efficiency of the titanium dioxide photocatalyst is dependent on the crystalline structure and the anatase phase presents high efficiency in the border region between the UV-B and UV-A, with a redox potential sufficient to generate hydroxyl radicals and superoxide ion in order to oxidate organic compounds. In spite of the organic matter degradation effectiveness, the efficiency can be reduced substantially due to the presence of crystalline defects, which act as premature recombination centers of the electron-hole pair. The increasing of calcining temperature allows the elimination of most of these defects, but the structural ordering at temperatures around 600°C eventually leads to the phase transition toward rutile, which is not photoactive. In this work, it was demonstrated through FTIR and XRD that the silicon modifier presence stabilizes the anatase phase even at temperatures as high as 900°C. (author)

  9. Carbon dioxide and climate

    International Nuclear Information System (INIS)

    1991-10-01

    Global climate change is a serious environmental concern, and the US has developed ''An Action Agenda'' to deal with it. At the heart of the US effort is the US Global Change Research Program (USGCRP), which has been developed by the Committee on Earth and Environmental Sciences (CEES) of the Federal Coordinating Council for Sciences, Engineering, and Technology (FCCSET). The USGCRP will provide the scientific basis for sound policy making on the climate-change issue. The DOE contribution to the USGCRP is the Carbon Dioxide Research Program, which now places particular emphasis on the rapid improvement of the capability to predict global and regional climate change. DOE's Carbon Dioxide Research Program has been addressing the carbon dioxide-climate change connection for more than twelve years and has provided a solid scientific foundation for the USGCRP. The expansion of the DOE effort reflects the increased attention that the Department has placed on the issue and is reflected in the National Energy Strategy (NES) that was released in 1991. This Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1991 and gives a brief overview of objectives, organization, and accomplishments. The Environmental Sciences Division of the Office of Health and Environmental Research, Office of Energy Research supports a Carbon Dioxide Research Program to determine the scientific linkage between the rise of greenhouse gases in the atmosphere, especially carbon dioxide, and climate and vegetation change. One facet is the Core CO 2 Program, a pioneering program that DOE established more than 10 years ago to understand and predict the ways that fossil-fuel burning could affect atmospheric CO 2 concentration, global climate, and the Earth's biosphere. Major research areas are: global carbon cycle; climate detection and models of climate change; vegetation research; resource analysis; and, information and integration

  10. Gold nanorod–based poly(lactic-co-glycolic acid with manganese dioxide core–shell structured multifunctional nanoplatform for cancer theranostic applications

    Directory of Open Access Journals (Sweden)

    Wang L

    2017-04-01

    Full Text Available Lei Wang,1–3 Dong Li,1,2 Yongwei Hao,1,2 Mengya Niu,1,2 Yujie Hu,1,2 Hongjuan Zhao,1,2 Junbiao Chang,2,3 Zhenzhong Zhang,1,2 Yun Zhang1,2 1School of Pharmaceutical Sciences, Zhengzhou University, 2Key Laboratory of Targeting Therapy and Diagnosis for Critical Disease, Henan Province, 3School of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, People’s Republic of China Abstract: Recently, photothermal therapy has become a promising strategy in tumor treatment. However, the therapeutic effect was seriously hampered by the low tissue penetration of laser. Therefore, in this study, radiofrequency (RF with better tissue penetration was used for tumor hyperthermia. First, one type of gold nanorods (AuNRs suitable for RF hyperthermia was selected. Then, poly(lactic-co-glycolic acid (PLGA nanoparticles (NPs loaded with AuNRs and docetaxel (DTX (PLGA/AuNR/DTX NPs were constructed. Finally, manganese dioxide (MnO2 ultrathin nanofilms were coated on the surfaces of PLGA/AuNR/DTX NPs by the reduction of KMnO4 to construct the PLGA/AuNR/DTX@MnO2 drug delivery system. This drug delivery system can not only be used for the combined therapy of chemotherapy and RF hyperthermia but can also produce Mn2+ to enable magnetic resonance imaging. Furthermore, the RF hyperthermia and the degradation of MnO2 can significantly promote the controlled drug release in a tumor region. The in vitro and in vivo results suggested that the PLGA/AuNR/DTX@MnO2 multifunctional drug delivery system is a promising nanoplatform for effective cancer theranostic applications. Keywords: poly(lactic-co-glycolic acid, gold nanorod, manganese dioxide, radiofrequency, hyperthermia, dual-mode imaging, controlled release

  11. Deposition of carbon dioxide

    International Nuclear Information System (INIS)

    2001-01-01

    In Norway, there is currently a debate about whether or not to build gas power stations. To meet the possibility of reduced emission quotas for carbon dioxide in the future, current interest focuses on the incorporation of large-scale separation and deposition of carbon dioxide when such plants are planned. A group of experts concludes that this technology will become self-financing by means of environmental taxes. From the environmental point of view, taxes upon production are to be preferred over taxes on consumption

  12. Does Carbon Dioxide Predict Temperature?

    OpenAIRE

    Mytty, Tuukka

    2013-01-01

    Does carbon dioxide predict temperature? No it does not, in the time period of 1880-2004 with the carbon dioxide and temperature data used in this thesis. According to the Inter Governmental Panel on Climate Change(IPCC) carbon dioxide is the most important factor in raising the global temperature. Therefore, it is reasonable to assume that carbon dioxide truly predicts temperature. Because this paper uses observational data it has to be kept in mind that no causality interpretation can be ma...

  13. Carbon Dioxide Sensor Technology.

    Science.gov (United States)

    1983-04-01

    second gas permeable membrane separates a compartment containing the non-aqueous " solvent dimethylsulfoxide , ( DMSO ), from the aqueous solution...compartment. In DMSO carbon dioxide can be irreversibly reduced electrochemically to * non-interfering products...current due to its reduction in the DMSO solution is proportional to the partial pressure of CO2 in the gas phase. Overall, the linear response and

  14. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J. (Discovery Bay Marine Laboratory, Univ. of the West Indies (JM))

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  15. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T J [Discovery Bay Marine Laboratory, Univ. of the West Indies (JM)

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  16. Carbon dioxide absorbent and method of using the same

    Science.gov (United States)

    Perry, Robert James [Niskayuna, NY; Lewis, Larry Neil [Scotia, NY; O'Brien, Michael Joseph [Clifton Park, NY; Soloveichik, Grigorii Lev [Latham, NY; Kniajanski, Sergei [Clifton Park, NY; Lam, Tunchiao Hubert [Clifton Park, NY; Lee, Julia Lam [Niskayuna, NY; Rubinsztajn, Malgorzata Iwona [Ballston Spa, NY

    2011-10-04

    In accordance with one aspect, the present invention provides an amino-siloxane composition comprising at least one of structures I, II, III, IV or V said compositions being useful for the capture of carbon dioxide from gas streams such as power plant flue gases. In addition, the present invention provides methods of preparing the amino-siloxane compositions are provided. Also provided are methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention as species which react with carbon dioxide to form an adduct with carbon dioxide. The reaction of the amino-siloxane compositions provided by the present invention with carbon dioxide is reversible and thus, the method provides for multicycle use of said compositions.

  17. Carbon dioxide dangers demonstration model

    Science.gov (United States)

    Venezky, Dina; Wessells, Stephen

    2010-01-01

    Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

  18. Cellular Response to Titanium Dioxide Nanoparticles in Intestinal Epithelial Caco-2 Cells is Dependent on Endocytosis-Associated Structures and Mediated by EGFR

    Science.gov (United States)

    Krüger, Kristin; Schrader, Katrin; Klempt, Martin

    2017-01-01

    Titanium dioxide (TiO2) is one of the most applied nanomaterials and widely used in food and non-food industries as an additive or coating material (E171). It has been shown that E171 contains up to 37% particles which are smaller than 100 nm and that TiO2 nanoparticles (NPs) induce cytotoxicity and inflammation. Using a nuclear factor Kappa-light-chain enhancer of activated B cells (NF-κB) reporter cell line (Caco-2nfkb-RE), Real time polymerase chain reaction (PCR), and inhibition of dynamin and clathrin, it was shown that cellular responses induced by 5 nm and 10 nm TiO2 NPs (nominal size) depends on endocytic processes. As endocytosis is often dependent on the epithelial growth factor receptor (EGFR), further investigations focused on the involvement of EGFR in the uptake of TiO2 NPs: (1) inhibition of EGFR reduced inflammatory markers of the cell (i.e., nuclear factor (NF)-κB activity, mRNA of IL8, CCL20, and CXCL10); and (2) exposure of Caco-2 cells to TiO2 NPs activated the intracellular EGFR cascade beginning with EGFR-mediated extracellular signal-regulated kinases (ERK)1/2, and including transcription factor ELK1. This was followed by the expression of ERK1/2 target genes CCL2 and CXCL3. We concluded that TiO2 NPs enter the cell via EGFR-associated endocytosis, followed by activation of the EGFR/ERK/ELK signaling pathway, which finally induces NF-κB. No changes in inflammatory response are observed in Caco-2 cells exposed to 32 nm and 490 nm TiO2 particles. PMID:28387727

  19. Cellular Response to Titanium Dioxide Nanoparticles in Intestinal Epithelial Caco-2 Cells is Dependent on Endocytosis-Associated Structures and Mediated by EGFR.

    Science.gov (United States)

    Krüger, Kristin; Schrader, Katrin; Klempt, Martin

    2017-04-07

    Titanium dioxide (TiO₂) is one of the most applied nanomaterials and widely used in food and non-food industries as an additive or coating material (E171). It has been shown that E171 contains up to 37% particles which are smaller than 100 nm and that TiO₂ nanoparticles (NPs) induce cytotoxicity and inflammation. Using a nuclear factor Kappa-light-chain enhancer of activated B cells (NF-κB) reporter cell line (Caco-2 nfkb-RE ), Real time polymerase chain reaction (PCR), and inhibition of dynamin and clathrin, it was shown that cellular responses induced by 5 nm and 10 nm TiO₂ NPs (nominal size) depends on endocytic processes. As endocytosis is often dependent on the epithelial growth factor receptor (EGFR), further investigations focused on the involvement of EGFR in the uptake of TiO₂ NPs: (1) inhibition of EGFR reduced inflammatory markers of the cell (i.e., nuclear factor (NF)-κB activity, mRNA of IL8, CCL20, and CXCL10); and (2) exposure of Caco-2 cells to TiO₂ NPs activated the intracellular EGFR cascade beginning with EGFR-mediated extracellular signal-regulated kinases (ERK)1/2, and including transcription factor ELK1. This was followed by the expression of ERK1/2 target genes CCL2 and CXCL3. We concluded that TiO₂ NPs enter the cell via EGFR-associated endocytosis, followed by activation of the EGFR/ERK/ELK signaling pathway, which finally induces NF-κB. No changes in inflammatory response are observed in Caco-2 cells exposed to 32 nm and 490 nm TiO₂ particles.

  20. Methanation of Carbon Dioxide

    OpenAIRE

    Goodman, Daniel Jacob

    2013-01-01

    The emission of greenhouse gases into the atmosphere has been linked to global warming. Carbon dioxide's (CO2) one of the most abundant greenhouse gases. Natural gas, mainly methane, is the cleanest fossil fuel for electricity production helping meet the United States ever growing energy needs. The methanation of CO2 has the potential to address both of these problems if a catalyst can be developed that meets the activity, economic and environmental requirements to industrialize the process. ...

  1. CARBON DIOXIDE FIXATION.

    Energy Technology Data Exchange (ETDEWEB)

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  2. Production of uranium dioxide

    International Nuclear Information System (INIS)

    Hart, J.E.; Shuck, D.L.; Lyon, W.L.

    1977-01-01

    A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF 6 ) to ceramic-grade uranium dioxide (UO 2 ) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF 6 with steam in a first fluidized bed, preferably at about 550 0 C, to form solid intermediate reaction products UO 2 F 2 , U 3 O 8 and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF 4 ). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630 0 C. The second intermediate reaction product including uranium dioxide (UO 2 ) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650 0 C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO 2 and increase the oxygen-uranium ratio to about 2.25

  3. CCDC 1046719: Experimental Crystal Structure Determination : catena-[(mu-2,5-dioxidoterephthalato)-(mu-carbon dioxide)-di-zinc unknown solvate

    KAUST Repository

    Luo, Feng

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. Titanium dioxide modified with various amines used as sorbents of carbon dioxide

    International Nuclear Information System (INIS)

    Kapica-Kozar, Joanna; Pirog, Ewa; Kusiak-Nejman, Ewelina; Wrobel, Rafal J.; Gesikiewicz-Puchalska, Andzelika; Morawski, Antoni W.; Narkiewicz, Urszula; Michalkiewicz, Beata

    2017-01-01

    In this study, titanium dioxide was modified with various amines through hydrothermal treatment for adsorption of CO_2. The carbon dioxide adsorption performance of the prepared samples was measured using an STA 449 C thermo-balance (Netzsch Company, Germany). The morphological structures, functional groups and elemental compositions of the unmodified and amine-modified titanium dioxide sorbents were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR/DR) and scanning electron microscopy (SEM), respectively. The results showed that modification of TiO_2 with amines through hydrothermal treatment is a simple method to prepare CO_2 sorbents with high adsorption capacities. Moreover, the results revealed that TEPA-modified titanium dioxide shoved the highest adsorption capacity, enabling an increase in CO_2 uptake from 0.45 mmol CO_2 g"-"1 in the case of raw TiO_2 to 1.63 mmol CO_2 g"-"1. This result could be indirectly related to the fact that TEPA has the highest amino group content among the three amines used in our research. Additionally, durability tests performed by cyclic adsorption-desorption revealed that TEPA modified titanium dioxide also possesses excellent stability, despite a slight decrease in adsorption capacity over time. (authors)

  5. Molybdenum dioxide-molybdenite roasting

    International Nuclear Information System (INIS)

    Sabacky, B.J.; Hepworth, M.T.

    1984-01-01

    A process is disclosed for roasting molybdenite concentrates directly to molybdenum dioxide. The process comprises establishing a roasting zone having a temperature of about 700 0 C. to about 800 0 C., introducing into the roasting zone particulate molybdenum dioxide and molybdenite in a weight ratio of at least about 2:1 along with an oxygen-containing gas in amount sufficient to oxidize the sulfur content of the molybdenite to molybdenum dioxide

  6. Process for sequestering carbon dioxide and sulfur dioxide

    Science.gov (United States)

    Maroto-Valer, M Mercedes [State College, PA; Zhang, Yinzhi [State College, PA; Kuchta, Matthew E [State College, PA; Andresen, John M [State College, PA; Fauth, Dan J [Pittsburgh, PA

    2009-10-20

    A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

  7. Carbon dioxide and climate

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

  8. The [BN{sub 2}]{sup 3-} anion. A carbon dioxide isosteric building unit for a large family of complex nitridoborate structures

    Energy Technology Data Exchange (ETDEWEB)

    Poettgen, Rainer; Reckeweg, Olaf [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-07-01

    The crystal chemistry of nitridoborates with the CO{sub 2} analogous [BN{sub 2}]{sup 3-} ion is reviewed. Such nitridoborates form with the alkali and alkaline earth metals as well as with divalent europium. Also quaternary compounds with mixed cations along with nitridoborate nitrides, oxides, halides and hydrides are discussed. The spectroscopic (IR, Raman, solid state NMR and Moessbauer spectroscopy) and magnetic behavior as well as optical properties are discussed in the light of structure-property relationships.

  9. Remote measurement of canopy reflectance shows the effects of elevated carbon dioxide and ozone on the structure and functioning of soybeans in a field setting.

    Science.gov (United States)

    Gray, S.; Dermody, O.; Delucia, E.

    2006-12-01

    By altering physiological processes and modifying canopy structure, elevated atmospheric CO2 and O3 directly and indirectly change the productivity of agroecosystems. Remote sensing of canopy reflectance can be used to monitor physiological and structural changes in an ecosystem over a growing season. To examine effects of changing tropospheric chemistry on water content, chlorophyll content, and changes in leaf area index (LAI), Free-Air Concentration Enrichment (FACE) technology was used to expose large plots of soybean (Glycine max) to elevated atmospheric CO2, elevated O3 (1.5 x ambient), and combined elevated CO2 and O3. The following indices were calculated from weekly measurements of reflectance: water index (WI), photochemical reflectance index (PRI), chlorophyll index, near-infrared/ red (NIR/red), and normalized difference vegetation index (NDVI). NIR/red and LAI were strongly correlated throughout the growth season; however NDVI and LAI were highly correlated only up to LAI of 3. Exposure to elevated CO2 accelerated early-season canopy development and delayed late-season senescence. Growth in elevated O3 had the opposite effect. Additionally, elevated CO2 compensated for negative effects of O3 when the canopy was exposed to both gases simultaneously. Reflectance indices revealed several physiological and structural responses of this agroecosystem to tropospheric change, and ultimately that elevated CO2 and O3 significantly affected this system's productivity and period for carbon gain.

  10. Influences of metallic doping on anatase crystalline titanium dioxide: From electronic structure aspects to efficiency of TiO2-based dye sensitized solar cell (DSSC)

    International Nuclear Information System (INIS)

    Nguyen, Thuy Trang; Tran, Van Nam; Bach, Thanh Cong

    2014-01-01

    In this work, we examined the influences of metallic X dopants (X = Be, Mg, Ca, Zn, Al, W and Nb) on the electronic structure of anatase TiO 2 in the framework of density functional theory (DFT). The dopant-induced electronic structure modifications are believed to directly change the photovoltaic (PV) behaviors of the X-doped TiO 2 based DSSCs. The dopants are shown to either directly inhibit the intrinsic Ti 3+ and oxygen vacancy surface defects of TiO 2 or enhance these defects depending on their valence states. These dopant-induced defect modifications, in turn, strongly affect the PV behaviors of the DSSCs. The combined effect of electronic structure and surface-defect modifications determined the photoelectric efficiency of the device. - Highlights: • Ca, Al and W dopants strongly distort the lattice and narrowed the band gap. • Nb negatively shifts while the others positive shift the conduction band bottom. • Nb and W dopants reduce Ti 4+ to Ti 3+ without forming oxygen vacancy. • Be, Mg, Ca, Zn and Al dopants induce oxygen vacancy without Ti 3+ . • Nb and W inhibit the surface defects while the others do the reversed manner

  11. 1,4,2-Benzo/pyridodithiazine 1,1-dioxides structurally related to the ATP-sensitive potassium channel openers 1,2,4-Benzo/pyridothiadiazine 1,1-dioxides exert a myorelaxant activity linked to a distinct mechanism of action.

    Science.gov (United States)

    Pirotte, Bernard; de Tullio, Pascal; Florence, Xavier; Goffin, Eric; Somers, Fabian; Boverie, Stéphane; Lebrun, Philippe

    2013-04-25

    The synthesis of diversely substituted 3-alkyl/aralkyl/arylamino-1,4,2-benzodithiazine 1,1-dioxides and 3-alkylaminopyrido[4,3-e]-1,4,2-dithiazine 1,1-dioxides is described. Their biological activities on pancreatic β-cells and on smooth muscle cells were compared to those of the reference ATP-sensitive potassium channel (KATP channel) openers diazoxide and 7-chloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide. The aim was to assess the impact on biological activities of the replacement of the 1,2,4-thiadiazine ring by an isosteric 1,4,2-dithiazine ring. Most of the dithiazine analogues were found to be inactive on the pancreatic tissue, although some compounds bearing a 1-phenylethylamino side chain at the 3-position exerted a marked myorelaxant activity. Such an effect did not appear to be related to the opening of KATP channels but rather reflected a mechanism of action similar to that of calcium channel blockers. Tightly related 3-(1-phenylethyl)sulfanyl-4H-1,2,4-benzothiadiazine 1,1-dioxides were also found to exert a pronounced myorelaxant activity, resulting from both a KATP channel activation and a calcium channel blocker mechanism. The present work highlights the critical importance of an intracyclic NH group at the 4-position, as well as an exocyclic NH group linked to the 3-position of the benzo- and pyridothiadiazine dioxides, for activity on KATP channels.

  12. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L [Batavia, IL; Ackerman, John P [Prescott, AZ; Williamson, Mark A [Naperville, IL

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  13. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1982-01-01

    A process for the preparation of a sintered, high density, large crystal grain size uranium dioxide pellet is described which involves: (i) reacting a uranyl nitrate of formula UO 2 (NO 3 ) 2 .6H 2 O with a sulphur source, at a temperature of from about 300 deg. C to provide a sulphur-containing uranium trioxide; (ii) reacting the thus-obtained modified uranium trioxide with ammonium nitrate to form an insoluble sulphur-containing ammonium uranate; (iii) neutralizing the thus-formed slurry with ammonium hydroxide to precipitate out as an insoluble ammonium uranate the remaining dissolved uranium; (iv) recovering the thus-formed precipitates in a dry state; (v) reducing the dry precipitate to UO 2 , and forming it into 'green' pellets; and (vi) sintering the pellets in a hydrogen atmosphere at an elevated temperature

  14. Forecasting carbon dioxide emissions.

    Science.gov (United States)

    Zhao, Xiaobing; Du, Ding

    2015-09-01

    This study extends the literature on forecasting carbon dioxide (CO2) emissions by applying the reduced-form econometrics approach of Schmalensee et al. (1998) to a more recent sample period, the post-1997 period. Using the post-1997 period is motivated by the observation that the strengthening pace of global climate policy may have been accelerated since 1997. Based on our parameter estimates, we project 25% reduction in CO2 emissions by 2050 according to an economic and population growth scenario that is more consistent with recent global trends. Our forecasts are conservative due to that we do not have sufficient data to fully take into account recent developments in the global economy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Uranium dioxide calcining apparatus

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 deg C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means. (author)

  16. The construction of ventilation turrets in Atta vollenweideri leaf-cutting ants: Carbon dioxide levels in the nest tunnels, but not airflow or air humidity, influence turret structure.

    Directory of Open Access Journals (Sweden)

    Florian Halboth

    Full Text Available Nest ventilation in the leaf-cutting ant Atta vollenweideri is driven via a wind-induced mechanism. On their nests, workers construct small turrets that are expected to facilitate nest ventilation. We hypothesized that the construction and structural features of the turrets would depend on the colony's current demands for ventilation and thus might be influenced by the prevailing environmental conditions inside the nest. Therefore, we tested whether climate-related parameters, namely airflow, air humidity and CO2 levels in the outflowing nest air influenced turret construction in Atta vollenweideri. In the laboratory, we simulated a semi-natural nest arrangement with fungus chambers, a central ventilation tunnel providing outflow of air and an aboveground building arena for turret construction. In independent series, different climatic conditions inside the ventilation tunnel were experimentally generated, and after 24 hours, several features of the built turret were quantified, i.e., mass, height, number and surface area (aperture of turret openings. Turret mass and height were similar in all experiments even when no airflow was provided in the ventilation tunnel. However, elevated CO2 levels led to the construction of a turret with several minor openings and a larger total aperture. This effect was statistically significant at higher CO2 levels of 5% and 10% but not at 1% CO2. The construction of a turret with several minor openings did not depend on the strong differences in CO2 levels between the outflowing and the outside air, since workers also built permeated turrets even when the CO2 levels inside and outside were both similarly high. We propose that the construction of turrets with several openings and larger opening surface area might facilitate the removal of CO2 from the underground nest structure and could therefore be involved in the control of nest climate in leaf-cutting ants.

  17. Carbon dioxide and future climate

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J M

    1977-03-01

    The addition of carbon dioxide to the atmosphere due to burning fossil fuel is discussed. The release rate of carbon dioxide has been growing since at least 1950 at an average rate of 4.3% per year. If all known fossil fuel reserves in the world are consumed, a total of between 5 and 14 times the present amount of carbon dioxide in the atmosphere will be released. The oceans would then be unlikely to withdraw the proportion of perhaps 40% which they are believed to have withdrawn up to the present. The increase in the atmosphere would be in excess of 3 times or conceivably ten times the present amount. If the reserves are used up within a few hundred years, more than half the excess carbon dioxide would remain in the atmosphere after a thousand years. The ''greenhouse'' effect of carbon dioxide is explained. The simulation with numerical models of the effects of carbon dioxide on atmospheric radiation fluxes is discussed. An estimated increase in the average annual temperature of the earth of 2.4 to 2.9C is given for doubling the carbon dioxide content; also a 7% increase in global average precipitation. The effect of increasing carbon dioxide on global mean temperature is viewed in the perspective of the glacial-interglacial cycles. The warming effect of carbon dioxide may induce a ''super-interglacial'' on the present interglacial which is expected to decline toward a new ice age in the next several thousand years. Finally it is proposed that it may be necessary to phase out the use of fossil fuels before all the knowledge is acquired which would necessitate such an action.

  18. Effects of Cr and Fe co-doping on structural, optical, electrical and magnetic properties of titanium dioxide (TiO2

    Directory of Open Access Journals (Sweden)

    Waseem Salma

    2015-09-01

    Full Text Available A series of Ti0.9Fe0.1-xCrxO2 (where x = 0.0, 0.02, 0.04, 0.6, 0.08, 0.10 was synthesized using the powder metallurgy route. The structural, morphological, magnetic, optical and electrical properties were investigated by X-ray diffractometry (XRD, Raman spectroscopy, scanning electron microscopy (SEM, vibrating sample magnetometry (VSM, UV-Vis spec­troscopy and four probe technique, respectively. The rutile phase was confirmed by XRD analysis which was also verified by Raman spectroscopy. It was observed that the grain size increased as the concentration of Cr increased. M-H loops ex­tracted from VSM analysis revealed anti-ferromagnetic, weak ferromagnetic and paramagnetic behaviors at room temperature. The band gap energy and resistivity measurements exhibited the semiconducting nature of Ti0.9Fe0.1-xCrxO2 based diluted magnetic semiconductors.

  19. Spatial and Temporal Variability of Carbon Dioxide Using Structure Functions in Urban Areas: Insights for Future Active Remote CO2 Sensors

    Science.gov (United States)

    Choi, Yonghoon; Yang, Melissa; Kooi, Susan A.; Browell, Edward V.; DiGangi, Joshua P.

    2015-01-01

    High resolution in-situ CO2 measurements were recorded onboard the NASA P-3B during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Field Campaigns during July 2011 over Washington DC/Baltimore, MD; January-February 2013 over the San Joaquin Valley, CA; September 2013 over Houston, TX; and July-August 2014 over Denver, CO. Each of these campaigns have approximately two hundred vertical soundings of CO2 within the lower troposphere (surface to about 5 kilometers) at 6-8 different sites in each of the urban areas. In this study, we used structure function analysis, which is a useful way to quantify spatial and temporal variability, by displaying differences with average observations, to evaluate the variability of CO2 in the 0-2 kilometers range (representative of the planetary boundary layer). These results can then be used to provide guidance in the development of science requirements for the future ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission to measure near-surface CO2 variability in different urban areas. We also compare the observed in-situ CO2 variability with the variability of the CO2 column-averaged optical depths in the 0-1 kilometer and 0-3.5 kilometers altitude ranges in the four geographically different urban areas, using vertical weighting functions for potential future ASCENDS lidar CO2 sensors operating in the 1.57 and 2.05 millimeter measurement regions. In addition to determining the natural variability of CO2 near the surface and in the column, radiocarbon method using continuous CO2 and CO measurements are used to examine the variation of emission quantification between anthropogenic and biogenic sources in the DC/Maryland urban site.

  20. Decontamination of radioactive clothing using microemulsion in carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jaeryong; Jang, Jina; Park, Kwangheon; Kim, Hongdoo; Kim, Hakwon [Kyunghee Univ., Seoul (Korea, Republic of); Yim, Sanghak; Yoon, Weonseob [Ulchin Nuclear Power Site, Ulchin (Korea, Republic of)

    2006-07-01

    Nuclear power is intrinsically a clean energy source due to its high energy density and low generation of waste. However, as the nuclear industry grows, a variety of radioactive wastes are increased gradually. Major subjects include contaminated components, tools, equipment, containers and facilities as well as nuclear waste such as uranium scrap and radioactive clothing. The radioactive waste can be classified by its creation. There are Trans-Uranium Nuclides (TRU), Fission Products (FP) and corrosion products. Nuclear decontamination has become an important issue in the nuclear industry. The conventional methods have some problems such as the production of secondary wastes and the use of toxic solvents. We need to develop a new method of decontamination and suggest a use of microemulsion in carbon dioxide to overcome these disadvantages. The microemulsion is the clear solution that contains the water, surfactant and carbon dioxide. The surfactant surrounded the droplet into carbon dioxide and this state is thermodynamically stable. That is, the microemulsion has a structure similar to that of a conventional water-based surfactant system. Generally, the size of droplet is about 5 {approx} 10nm. The microemulsion is able to decontaminate radioactive waste so that the polar substance is removed by water and the non-polar substance is removed by carbon dioxide. After the decontamination process, the microemulsion is separated easily to surfactant and water by decreasing the pressure under the cloud point. This way, only radioactive wastes are left in the system. Cleaned carbon dioxide is then collected and reused. Thus, there are no secondary wastes. Carbon dioxide is considered an alternative process medium. This is because it is non-toxic, non-flammable, inexpensive and easy to handle. Additionally, the tunable properties of carbon dioxide through pressure and temperature control are versatile for use in extracting organic materials. In this paper, we examine the

  1. Decontamination of radioactive clothing using microemulsion in carbon dioxide

    International Nuclear Information System (INIS)

    Yoo, Jaeryong; Jang, Jina; Park, Kwangheon; Kim, Hongdoo; Kim, Hakwon; Yim, Sanghak; Yoon, Weonseob

    2006-01-01

    Nuclear power is intrinsically a clean energy source due to its high energy density and low generation of waste. However, as the nuclear industry grows, a variety of radioactive wastes are increased gradually. Major subjects include contaminated components, tools, equipment, containers and facilities as well as nuclear waste such as uranium scrap and radioactive clothing. The radioactive waste can be classified by its creation. There are Trans-Uranium Nuclides (TRU), Fission Products (FP) and corrosion products. Nuclear decontamination has become an important issue in the nuclear industry. The conventional methods have some problems such as the production of secondary wastes and the use of toxic solvents. We need to develop a new method of decontamination and suggest a use of microemulsion in carbon dioxide to overcome these disadvantages. The microemulsion is the clear solution that contains the water, surfactant and carbon dioxide. The surfactant surrounded the droplet into carbon dioxide and this state is thermodynamically stable. That is, the microemulsion has a structure similar to that of a conventional water-based surfactant system. Generally, the size of droplet is about 5 ∼ 10nm. The microemulsion is able to decontaminate radioactive waste so that the polar substance is removed by water and the non-polar substance is removed by carbon dioxide. After the decontamination process, the microemulsion is separated easily to surfactant and water by decreasing the pressure under the cloud point. This way, only radioactive wastes are left in the system. Cleaned carbon dioxide is then collected and reused. Thus, there are no secondary wastes. Carbon dioxide is considered an alternative process medium. This is because it is non-toxic, non-flammable, inexpensive and easy to handle. Additionally, the tunable properties of carbon dioxide through pressure and temperature control are versatile for use in extracting organic materials. In this paper, we examine the

  2. Extraction of Uranium Using Nitrogen Dioxide and Carbon Dioxide for Spent Fuel Reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kayo Sawada; Daisuke Hirabayashi; Youichi Enokida [EcoTopia Science Institute, Nagoya University, Nagoya, 464-8603 (Japan)

    2008-07-01

    For the reprocessing of spent nuclear fuels, a new method to extract actinides from spent fuel using highly compressed gases, nitrogen dioxide and carbon dioxide was proposed. Uranium extraction from broken pieces, whose average grain size was 5 mm, of uranium dioxide pellet with nitrogen dioxide and carbon dioxide was demonstrated in the present study. (authors)

  3. Hydrothermal synthesis of tungsten doped tin dioxide nanocrystals

    Science.gov (United States)

    Zhou, Cailong; Li, Yufeng; Chen, Yiwen; Lin, Jing

    2018-01-01

    Tungsten doped tin dioxide (WTO) nanocrystals were synthesized through a one-step hydrothermal method. The structure, composition and morphology of WTO nanocrystals were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, UV-vis diffuse reflectance spectra, zeta potential analysis and high-resolution transmission electron microscopy. Results show that the as-prepared WTO nanocrystals were rutile-type structure with the size near 13 nm. Compared with the undoped tin dioxide nanocrystals, the WTO nanocrystals possessed better dispersity in ethanol phase and formed transparent sol.

  4. Reducing carbon dioxide to products

    Science.gov (United States)

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  5. Method for carbon dioxide sequestration

    Science.gov (United States)

    Wang, Yifeng; Bryan, Charles R.; Dewers, Thomas; Heath, Jason E.

    2017-12-05

    A method for geo-sequestration of a carbon dioxide includes selection of a target water-laden geological formation with low-permeability interbeds, providing an injection well into the formation and injecting supercritical carbon dioxide (SC-CO.sub.2) and water or bine into the injection well under conditions of temperature, pressure and density selected to cause the fluid to enter the formation and splinter and/or form immobilized ganglia within the formation.

  6. Recuperative supercritical carbon dioxide cycle

    Science.gov (United States)

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

    2014-11-18

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  7. The preparation and the sustained release of titanium dioxide hollow particles encapsulating L-ascorbic acid

    Science.gov (United States)

    Tominaga, Yoko; Kadota, Kazunori; Shimosaka, Atsuko; Yoshida, Mikio; Oshima, Kotaro; Shirakawa, Yoshiyuki

    2018-05-01

    The preparation of the titanium dioxide hollow particles encapsulating L-ascorbic acid via sol-gel process using inkjet nozzle has been performed, and the sustained release and the effect protecting against degradation of L-ascorbic acid in the particles were investigated. The morphology of titanium dioxide particles was evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The sustained release and the effect protecting against degradation of L-ascorbic acid were estimated by dialysis bag method in phosphate buffer saline (PBS) (pH = 7.4) as release media. The prepared titanium dioxide particles exhibited spherical porous structures. The particle size distribution of the titanium dioxide particles was uniform. The hollow titanium dioxide particles encapsulating L-ascorbic acid showed the sustained release. It was also found that the degradation of L-ascorbic acid could be inhibited by encapsulating L-ascorbic acid in the titanium dioxide hollow particles.

  8. Study by X-ray diffraction of structure modifications induced by pressure in different actinide compounds: AnO2 dioxides (An=Th, Pu, Am), AnCl4 tetrachlorides (An=Th, U), UBx borides (x=2,4,12) and the carbide UC2

    International Nuclear Information System (INIS)

    Dancausse, J.P.

    1991-01-01

    Structural transitions, induced by pressure, of actinide compounds are studied by X-ray diffraction, the determination of incompressibility is also studied at atmospheric pressure. The crystal structure of ThO 2 , PuO 2 and AmO 2 evolves, near 40 MPa from a fcc lattice to an orthorhombic lattice. Incompressibility values associated to UO 2 and NpO 2 incompressibility evidence an important discontinuity between UO 2 and NpO 2 and other dioxides due to their different electronic structure. Tetragonal ThCl 4 and UCl 4 undergo a structure transition respectively at 2 and 5 GPa. UCl 4 becomes monoclinic and its color changes. At higher pressure these compounds become progressively amorphous. The crystal structure of uranium borides is not changed up to 50 GPa. UC 2 presents a phase transition at 17.6 GPa from a tetragonal to a hexagonal lattice

  9. High-pressure behavior of nano titanium dioxide

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Jiang, Jianzhong

    2002-01-01

    Nanocrystalline rutile Titanium dioxide has been studied by X-ray diffraction at ambient temperature up to 47.4 GPa. The material is found to transform to the monoclinic baddeleyite structure between 20 and 30 GPa, which is higher than the corresponding pressure range for bulk material. Upon deco...

  10. Study of effect of chromium on titanium dioxide phase transformation ...

    Indian Academy of Sciences (India)

    Administrator

    Study of effect of chromium on titanium dioxide phase transformation by A Bellifa (pp 669–677). Figure S1. Structural ... 4 × 1⋅9486; 2 × 1⋅9799. Octahedral packing. 2 × 2 shared edges. 8 free edges. 3 shared edges. 4 corners. 5 free edges. 2 parallel shared edges. 2 corners. 10 free edges. O. O. Coordination scheme.

  11. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    DEFF Research Database (Denmark)

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum

    2017-01-01

    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energy...

  12. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION; SEMIANNUAL

    International Nuclear Information System (INIS)

    Jerry Y.S. Lin; Jun-ichi Ida

    2001-01-01

    This project is aimed at demonstrating technical feasibility for a lithium zirconate based dense ceramic membrane for separation of carbon dioxide from flue gas at high temperature. The research work conducted in this reporting period was focused on several fundamental issues of lithium zirconate important to the development of the dense inorganic membrane. These fundamental issues include material synthesis of lithium zirconate, phases and microstructure of lithium zirconate and structure change of lithium zirconate during sorption/desorption process. The results show difficulty to prepare the dense ceramic membrane from pure lithium zirconate, but indicate a possibility to prepare the dense inorganic membrane for carbon dioxide separation from a composite lithium zirconate

  13. Carbon dioxide: emissions and effects

    Energy Technology Data Exchange (ETDEWEB)

    Smith, I M

    1982-01-01

    This review provides a comprehensive guide to work carried out since 1978 in the many disciplines involved in this complex issue. Possible scenarios for carbon dioxide emissions, sources and sinks in the carbon cycle and for climatic changes are examined. The current concensus (by no means unanimous) of specialists on this issue appears to be that a continuation of reduced trends in energy consumption since 1973 is likely to double the atmospheric carbon dioxide concentration to 600 ppmv during the latter part of the next century. However, a higher demand scenario, requiring an upper limit of coal production, would bring forward the doubling to about the middle of the next century. Current climatic models predict that such a concentration of carbon dioxide would cause an average global warming of from 1.0 to 4.5/sup 0/C which might be delayed by the thermal inertia of the oceans. A warming due to estimated increases in carbon dioxide should, if the model results are correct, become apparent at the end of this century. Regional climatic changes are likely to vary considerably and prove disadvantageous to some regions and beneficial to others. Different strategies for dealing with the carbon dioxide issue are considered: no response, alleviation, countermeasures and prevention. It is concluded that uncertainties do not justify either the use of carbon dioxide disposal and other technical fixes at present or a policy of no further growth in fossil fuel consumption. On the other hand, major efforts to conserve energy would give more time to adapt to changes. The alleviation of climatic impacts and other desirable dual-benefit measures are advocated in addition to continuing international, interdisciplinary research on all aspects.

  14. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  15. Tunable functionality and toxicity studies of titanium dioxide nanotube layers

    International Nuclear Information System (INIS)

    Feschet-Chassot, E.; Raspal, V.; Sibaud, Y.; Awitor, O.K.; Bonnemoy, F.; Bonnet, J.L.; Bohatier, J.

    2011-01-01

    In this study, we have developed a simple process to fabricate scalable titanium dioxide nanotube layers which show a tunable functionality. The titanium dioxide nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt.% hydrofluoric acid solution. The nanotube layers structure and morphology were characterized using X-ray diffraction and scanning electron microscopy. The surface topography and wettability were studied according to the anodization time. The sample synthesized displayed a higher contact angle while the current density reached a local minimum. Beyond this point, the contact angles decreased with anodization time. Photo-degradation of acid orange 7 in aqueous solution was used as a probe to assess the photocatalytic activity of titanium dioxide nanotube layers under UV irradiation. We obtained better photocatalytic activity for the sample fabricated at higher current density. Finally we used the Ciliated Protozoan T. pyriformis, an alternative cell model used for in vitro toxicity studies, to predict the toxicity of titanium dioxide nanotube layers in a biological system. We did not observe any characteristic effect in the presence of the titanium dioxide nanotube layers on two physiological parameters related to this organism, non-specific esterases activity and population growth rate.

  16. Carbon materials-functionalized tin dioxide nanoparticles toward robust, high-performance nitrogen dioxide gas sensor.

    Science.gov (United States)

    Zhang, Rui; Liu, Xiupeng; Zhou, Tingting; Wang, Lili; Zhang, Tong

    2018-08-15

    Carbon (C) materials, which process excellent electrical conductivity and high carrier mobility, are promising sensing materials as active units for gas sensors. However, structural agglomeration caused by chemical processes results in a small resistance change and low sensing response. To address the above issues, structure-derived carbon-coated tin dioxide (SnO 2 ) nanoparticles having distinct core-shell morphology with a 3D net-like structure and highly uniform size are prepared by careful synthesis and fine structural design. The optimum carbon-coated SnO 2 nanoparticles (SnO 2 /C)-based gas sensor exhibits a low working temperature, excellent selectivity and fast response-recovery properties. In addition, the SnO 2 /C-based gas sensor can maintain a sensitivity to nitrogen dioxide (NO 2 ) of 3 after being cycled 4 times at 140 °C for, suggesting its good long-term stability. The structural integrity, good synergistic properties, and high gas-sensing performance of SnO 2 /C render it a promising sensing material for advanced gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Importance of halogen···halogen contacts for the structural and magnetic properties of CuX2(pyrazine-N,N′-dioxide)(H2O)2 (X = Cl and Br).

    Science.gov (United States)

    Schlueter, John A; Park, Hyunsoo; Halder, Gregory J; Armand, William R; Dunmars, Cortney; Chapman, Karena W; Manson, Jamie L; Singleton, John; McDonald, Ross; Plonczak, Alex; Kang, Jinhee; Lee, Chaghoon; Whangbo, Myung-Hwan; Lancaster, Tom; Steele, Andrew J; Franke, Isabel; Wright, Jack D; Blundell, Stephen J; Pratt, Francis L; deGeorge, Joseph; Turnbull, Mark M; Landee, Christopher P

    2012-02-20

    The structural and magnetic properties of the newly crystallized CuX(2)(pyzO)(H(2)O)(2) (X = Cl, Br; pyzO = pyrazine-N,N'-dioxide) coordination polymers are reported. These isostructural compounds crystallize in the monoclinic space group C2/c with, at 150 K, a = 17.0515(7) Å, b = 5.5560(2) Å, c = 10.4254(5) Å, β = 115.400(2)°, and V = 892.21(7) Å(3) for X = Cl and a = 17.3457(8) Å, b = 5.6766(3) Å, c = 10.6979(5) Å, β = 115.593(2)°, and V = 950.01(8) Å(3) for X = Br. Their crystal structure is characterized by one-dimensional chains of Cu(2+) ions linked through bidentate pyzO ligands. These chains are joined together through OH···O hydrogen bonds between the water ligands and pyzO oxygen atoms and Cu-X···X-Cu contacts. Bulk magnetic susceptibility measurements at ambient pressure show a broad maximum at 7 (Cl) and 28 K (Br) that is indicative of short-range magnetic correlations. The dominant spin exchange is the Cu-X···X-Cu supersuperexchange because the magnetic orbital of the Cu(2+) ion is contained in the CuX(2)(H(2)O)(2) plane and the X···X contact distances are short. The magnetic data were fitted to a Heisenberg 1D uniform antiferromagnetic chain model with J(1D)/k(B) = -11.1(1) (Cl) and -45.9(1) K (Br). Magnetization saturates at fields of 16.1(3) (Cl) and 66.7(5) T (Br), from which J(1D) is determined to be -11.5(2) (Cl) and -46.4(5) K (Br). For the Br analog the pressure dependence of the magnetic susceptibility indicates a gradual increase in the magnitude of J(1D)/k(B) up to -51.2 K at 0.84 GPa, suggesting a shortening of the Br···Br contact distance under pressure. At higher pressure X-ray powder diffraction data indicates a structural phase transition at ∼3.5 GPa. Muon-spin relaxation measurements indicate that CuCl(2)(pyzO)(H(2)O)(2) is magnetically ordered with T(N) = 1.06(1) K, while the signature for long-range magnetic order in CuBr(2)(pyzO)(H(2)O)(2) was much less definitive down to 0.26 K. The results for the Cu

  18. Carbon Dioxide Embolism during Laparoscopic Surgery

    Science.gov (United States)

    Park, Eun Young; Kwon, Ja-Young

    2012-01-01

    Clinically significant carbon dioxide embolism is a rare but potentially fatal complication of anesthesia administered during laparoscopic surgery. Its most common cause is inadvertent injection of carbon dioxide into a large vein, artery or solid organ. This error usually occurs during or shortly after insufflation of carbon dioxide into the body cavity, but may result from direct intravascular insufflation of carbon dioxide during surgery. Clinical presentation of carbon dioxide embolism ranges from asymptomatic to neurologic injury, cardiovascular collapse or even death, which is dependent on the rate and volume of carbon dioxide entrapment and the patient's condition. We reviewed extensive literature regarding carbon dioxide embolism in detail and set out to describe the complication from background to treatment. We hope that the present work will improve our understanding of carbon dioxide embolism during laparoscopic surgery. PMID:22476987

  19. Degradation of sulfur dioxide using plasma technology

    International Nuclear Information System (INIS)

    Estrada M, N.; Garcia E, R.; Pacheco P, M.; Valdivia B, R.; Pacheco S, J.

    2013-01-01

    This paper presents the electro-chemical study performed for sulfur dioxide (SO 2 ) treatment using non thermal plasma coupled to a nano structured fluid bed enhancing the toxic gas removal and the adsorption of acids formed during plasma treatment, more of 80% of removal was obtained. Non thermal plasma was ignited by dielectric barrier discharge (Dbd). The research was developed through an analysis of the chemical kinetics of the process and experimental study of degradation; in each experiment the electrical parameters and the influence of carbon nano structures were monitored to establish the optimal conditions of degradation. We compared the theoretical and experimental results to conclude whether the proposed model is correct for degradation. (Author)

  20. Hodgkin's disease following thorium dioxide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Gotlieb, A I; Kirk, M E [McGill Univ., Montreal, Quebec (Canada). Dept. of Pathology; Hutchison, J L [Montreal General Hospital, Quebec (Canada)

    1976-09-04

    Hodgkin's disease occurred in a 53-year-old man who, 25 years previously, had undergone cerebral angiography, for which thorium dioxide suspension (Thorotrast) was used. Deposits of thorium dioxide were noted in reticuloendothelial cells in various locations. An association between thorium dioxide administration and the subsequent development of malignant tumours and neoplastic hematologic disorders has previously been reported.

  1. 21 CFR 582.1240 - Carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Carbon dioxide. 582.1240 Section 582.1240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1240 Carbon dioxide. (a) Product. Carbon dioxide. (b) Conditions of use. This substance is generally...

  2. 21 CFR 73.1575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  3. 40 CFR 180.1195 - Titanium dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or on...

  4. 21 CFR 73.2575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  5. 21 CFR 73.575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2) Color...

  6. 21 CFR 73.3126 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891, shall...

  7. Crystal structures of [Ln(NO33(μ2-bpydo2], where Ln = Ce, Pr or Nd, and bpydo = 4,4′-bipyridine N,N′-dioxide: layered coordination networks containing 44 grids

    Directory of Open Access Journals (Sweden)

    Michael L. Stromyer

    2016-01-01

    Full Text Available Three isostructural coordination networks of Ce, Pr, and Nd nitrate with 4,4′-bipyridine N,N′-dioxide (bpydo are reported, namely poly[[tris(nitrato-κ2O,O′cerium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Ce(NO33(C10H8N2O22], poly[[tris(nitrato-κ2O,O′praeseodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Pr(NO33(C10H8N2O22], and poly[[tris(nitrato-κ2O,O′neodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Nd(NO33(C10H8N2O22]. All three compounds are isostructural to the previously reported La analogue. The asymmetric unit of [Ln(NO33(μ2-bpydo2] contains one lanthanide cation, two bpydo ligands, and three nitrate anions. Both bpydo ligands act as end-to-end μ2-bridges and display nearly ideal cis and gauche conformations, respectively. The bpydo ligands link the ten-coordinate LnIII cations, forming interdigitating 44 grid-like layers extending parallel to (-101, where interdigitation of layers is promoted by C—H...O interactions between nitrate anions and bpydo ligands. The interdigitated layers are linked to sets of neighboring layers via further C—H...O and π–π interactions.

  8. Radiation induced sulfur dioxide removal

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2000-01-01

    The biggest source of air pollution is the combustion of fossil fuels, were pollutants such as particulate, sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NO x ) removal processes, which is based on pure radiation induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanism of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kaweczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland. (author)

  9. Modelling Sublimation of Carbon Dioxide

    Science.gov (United States)

    Winkel, Brian

    2012-01-01

    In this article, the author reports results in their efforts to model sublimation of carbon dioxide and the associated kinetics order and parameter estimation issues in their model. They have offered the reader two sets of data and several approaches to determine the rate of sublimation of a piece of solid dry ice. They presented several models…

  10. Thermal conductivity of uranium dioxide

    International Nuclear Information System (INIS)

    Pillai, C.G.S.; George, A.M.

    1993-01-01

    The thermal conductivity of uranium dioxide of composition UO 2.015 was measured from 300 to 1400 K. The phonon component of the conductivity is found to be quantitatively accounted for by the theoretical expression of Slack derived by modifying the Leibfried-Schlomann equation. (orig.)

  11. Modeling 4f–4f intensity parameters as a function of structural distortions in Ln(2,2′-bipyridine-1,1′-dioxide){sub 4}(ClO{sub 4}){sub 3} complexes (Ln=Pr{sup 3+}, Nd{sup 3+})

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, A.N. [Departamento de Química Fundamental, Universidade Federal de Pernambuco-CCEN, Cidade Universitária, Recife-PE 50670-901 (Brazil); Huskowska, E.; Gawryszewska, P. [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw (Poland); Legendziewicz, J., E-mail: janina.legendziewicz@chem.uni.wroc.pl [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw (Poland); Malta, O.L. [Departamento de Química Fundamental, Universidade Federal de Pernambuco-CCEN, Cidade Universitária, Recife-PE 50670-901 (Brazil)

    2016-01-15

    This work reports on the influence of structural distortions on 4f–4f intensity parameters. These distortions in the first coordination sphere were applied to two complexes with similar structures, Ln(bpyO{sub 2}){sub 4}(ClO{sub 4}){sub 3} (Ln=Pr{sup 3+}, Nd{sup 3+} ions and bpyO{sub 2}=2,2′-bipyridine-1,1′-dioxide). The 4f–4f intensity theory and the PM3/Sparkle model were used. It is concluded that larger distortions are predicted in the case of the Pr complex, and that this point might contribute to the rationalization of the much higher values of the Ω{sub λ} intensity parameters in the Pr complex than in the Nd one. - Highlights: • The influence of structural distortions on 4f–4f intensity parameters was demonstrated for Nd and Pr complexes with 2,2′-bipyridine-1,1′-dioxide.

  12. Low temperature sintering of hyperstoichiometric uranium dioxide

    International Nuclear Information System (INIS)

    Chevrel, H.

    1991-12-01

    In the lattice of uranium dioxide with hyperstoichiometric oxygen content (UO 2+x ), each additional oxygen atoms is introduced by shifting two anions from normal sites to interstitial ones, thereby creating two oxygen vacancies. The point defects then combine to form complex defects comprising several interstitials and vacancies. The group of anions (3x) in the interstitial position participate in equilibria promoting the creation of uranium vacancies thereby considerably increasing uranium self-diffusion. However, uranium grain boundaries diffusion governs densification during the first two stages of sintering of uranium dioxide with hyperstoichiometric oxygen content, i.e., up to 93% of the theoretical density. Surface diffusion and evaporation-condensation, which are considerably accentuated by the hyperstoichiometric deviation, play an active role during sintering by promoting crystalline growth during the second and third stages of sintering. U 8 O 8 can be added to adjust the stoichiometry and to form a finely porous structure and thus increase the pore area subjected to surface phenomena. The composition with an O/U ratio equal to 2.25 is found to densify the best, despite a linear growth in sintering activation energy with hyperstoichiometric oxygen content, increasing from 300 kj.mol -1 for UO 2.10 to 440 kJ.mol -1 for UO 2.25 . Seeds can be introduced to obtain original microstructures, for example the presence of large grains in small-grain matrix

  13. Antibotulinal efficacy of sulfur dioxide in meat.

    Science.gov (United States)

    Tompkin, R B; Christiansen, L N; Shaparis, A B

    1980-01-01

    The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulfur dioxide offers a new option for the control of botulinal outgrowth in cured or noncured meat and poultry products. PMID:6996613

  14. Perspectives in the use of carbon dioxide

    Directory of Open Access Journals (Sweden)

    Aresta Michele

    1999-01-01

    Full Text Available The mitigation of carbon dioxide is one of the scientific and technological challenges of the 2000s. Among the technologies that are under assessment, the recovery of carbon dioxide from power plants or industrial flue gases plays a strategic role. Recovered carbon dioxide can be either disposed in natural fields or used. The availability of large amounts of carbon dioxide may open new routes to its utilisation in biological, chemical and innovative technological processes. In this paper, the potential of carbon dioxide utilisation in the short-, medium-term is reviewed.

  15. Layered tin dioxide microrods

    International Nuclear Information System (INIS)

    Duan Junhong; Huang Hongbo; Gong Jiangfeng; Zhao Xiaoning; Cheng Guangxu; Yang Shaoguang

    2007-01-01

    Single-crystalline layered SnO 2 microrods were synthesized by a simple tin-water reaction at 900 deg. C. The structural and optical properties of the sample were characterized by x-ray powder diffraction, energy-dispersive x-ray spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, Raman scattering and photoluminescence (PL) spectroscopy. High resolution transmission electron microscopy studies and selected area electron diffraction patterns revealed that the layered SnO 2 microrods are single crystalline and their growth direction is along [1 1 0]. The growth mechanism of the microrods was proposed based on SEM, TEM characterization and thermodynamic analysis. It is deduced that the layered microrods grow by the stacking of SnO 2 sheets with a (1 1 0) surface in a vapour-liquid-solid process. Three emission peaks at 523, 569 and 626 nm were detected in room-temperature PL measurements

  16. High capacity carbon dioxide sorbent

    Science.gov (United States)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  17. Oxygen and carbon dioxide sensing

    Science.gov (United States)

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  18. Carbon dioxide retention in divers

    Energy Technology Data Exchange (ETDEWEB)

    Florio, J.T.; Mackenzie, D.A.R.; McKenzie, R.S. [ARE Physiological Laboratory, Gosport (United Kingdom)

    1998-04-01

    This report summarises the work carried out at the ARE Physiological Laboratory (ARE(PL)) between July 1978 and December 1983. The work was intended to examine the proposition that some divers have a low ventilatory response to carbon dioxide; that this results in a low ventilatory response to exercise with consequent hypercapnia; and that these characteristics put the diver at a greater-than-normal risk by increasing the individual`s susceptibility to oxygen toxicity and to other hazards associated with diving (e.g. nitrogen narcosis, decompression sickness and hypothermia). The specific aims of the project can be summarised as follows: (a) to demonstrate the existence of divers who exhibit the tendency to `retain carbon dioxide` when working in hyperbaric conditions; (b) to define the circumstances under which such individuals are at risk; (c) to assess the magnitude of the risk; and (d) to recommend ways to eliminate or to reduce the risk. (author)

  19. CARBON DIOXIDE AS A FEEDSTOCK.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,C.; FUJITA,E.

    2000-12-09

    This report is an overview on the subject of carbon dioxide as a starting material for organic syntheses of potential commercial interest and the utilization of carbon dioxide as a substrate for fuel production. It draws extensively on literature sources, particularly on the report of a 1999 Workshop on the subject of catalysis in carbon dioxide utilization, but with emphasis on systems of most interest to us. Atmospheric carbon dioxide is an abundant (750 billion tons in atmosphere), but dilute source of carbon (only 0.036 % by volume), so technologies for utilization at the production source are crucial for both sequestration and utilization. Sequestration--such as pumping CO{sub 2} into sea or the earth--is beyond the scope of this report, except where it overlaps utilization, for example in converting CO{sub 2} to polymers. But sequestration dominates current thinking on short term solutions to global warming, as should be clear from reports from this and other workshops. The 3500 million tons estimated to be added to the atmosphere annually at present can be compared to the 110 million tons used to produce chemicals, chiefly urea (75 million tons), salicylic acid, cyclic carbonates and polycarbonates. Increased utilization of CO{sub 2} as a starting material is, however, highly desirable, because it is an inexpensive, non-toxic starting material. There are ongoing efforts to replace phosgene as a starting material. Creation of new materials and markets for them will increase this utilization, producing an increasingly positive, albeit small impact on global CO{sub 2} levels. The other uses of interest are utilization as a solvent and for fuel production and these will be discussed in turn.

  20. Manufacture of uranium dioxide powder

    International Nuclear Information System (INIS)

    Becker, M.

    1976-01-01

    Uranium dioxide powder is prepared by the AUC (ammonium uranyl carbonate) method. Supplementing the known process steps, the AUC, after separation from the mother liquor, is washed with an ammonium hydrogen carbonate or an NH 4 OH solution and is subsequently post-treated with a liquid which reduces the surface tension of the residual water in an AUC. Such a liquid is, for instance, alcohol

  1. Growth and characterization of iridium dioxide nanorods

    International Nuclear Information System (INIS)

    Chen, R.S.; Huang, Y.S.; Liang, Y.M.; Tsai, D.S.; Tiong, K.K.

    2004-01-01

    Conductive iridium dioxide (IrO 2 ) nanorods have been successfully grown on the Si(1 0 0) substrates via metalorganic chemical vapor deposition (MOCVD). A wedge-shaped morphology and naturally formed sharp tips are observed for IrO 2 nanorods using field-emission scanning electron microscopy (FESEM). High-resolution transmission electron microscopy (TEM) image and electron diffraction pattern show the growth of IrO 2 nanorods preferentially along c-axis. Structure and composition of IrO 2 nanorods have also been characterized using the techniques of Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. It is noted that the IrO 2 nanorods are self-mediated instead of the conventional vapor-liquid-solid (VLS) approach or catalyst-mediated method

  2. Carbon dioxide capture and storage

    International Nuclear Information System (INIS)

    Durand, B.

    2011-01-01

    The author first highlights the reasons why storing carbon dioxide in geological formations could be a solution in the struggle against global warming and climate change. Thus, he comments various evolutions and prospective data about carbon emissions or fossil energy consumption as well as various studies performed by international bodies and agencies which show the interest of carbon dioxide storage. He comments the evolution of CO 2 contributions of different industrial sectors and activities, notably in France. He presents the different storage modes and methods which concern different geological formations (saline aquifers, abandoned oil or gas fields, not exploitable coal seams) and different processes (sorption, carbonation). He discusses the risks associated with these storages, the storable quantities, evokes some existing installations in different countries. He comments different ways to capture carbon dioxide (in post-combustion, through oxy-combustion, by pre-combustion) and briefly evokes some existing installations. He evokes the issue of transport, and discusses efficiency and cost aspects, and finally has few words on legal aspects and social acceptability

  3. Carbon Dioxide Removal via Passive Thermal Approaches

    Science.gov (United States)

    Lawson, Michael; Hanford, Anthony; Conger, Bruce; Anderson, Molly

    2011-01-01

    A paper describes a regenerable approach to separate carbon dioxide from other cabin gases by means of cooling until the carbon dioxide forms carbon dioxide ice on the walls of the physical device. Currently, NASA space vehicles remove carbon dioxide by reaction with lithium hydroxide (LiOH) or by adsorption to an amine, a zeolite, or other sorbent. Use of lithium hydroxide, though reliable and well-understood, requires significant mass for all but the shortest missions in the form of lithium hydroxide pellets, because the reaction of carbon dioxide with lithium hydroxide is essentially irreversible. This approach is regenerable, uses less power than other historical approaches, and it is almost entirely passive, so it is more economical to operate and potentially maintenance- free for long-duration missions. In carbon dioxide removal mode, this approach passes a bone-dry stream of crew cabin atmospheric gas through a metal channel in thermal contact with a radiator. The radiator is pointed to reject thermal loads only to space. Within the channel, the working stream is cooled to the sublimation temperature of carbon dioxide at the prevailing cabin pressure, leading to formation of carbon dioxide ice on the channel walls. After a prescribed time or accumulation of carbon dioxide ice, for regeneration of the device, the channel is closed off from the crew cabin and the carbon dioxide ice is sublimed and either vented to the environment or accumulated for recovery of oxygen in a fully regenerative life support system.

  4. Optical and structural characterization of titanium dioxide films growth by the r f-sputtering technique; Caracterizacion optica y estructural de peliculas de dioxido de titanio crecidas por la tecnica de rf-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Florido C, A.; Calderon, A. [CICATA-IPN, Av. Legaria 694, 11500 Mexico D.F. (Mexico); Mendoza A, J.G.; Becerril, M.; Zelaya A, O. [CINVESTAV, A.P. 14-740, 07000 Mexico D.F. (Mexico)

    2007-07-01

    Full text: The elaboration of a series of grown films of TiO on Corning glaze substrates, as well as silicon, by means of the rf-sputtering technique using one power of 160 watts, with the objective of obtaining the anatase phase which one presents better activity for applications in photo catalysis. In the process of growth it was used a temperature in the range from 300 to 600 C and a separation distance among the target and the substrate of 3.5 cm. The used atmosphere was a mixture of argon and oxygen. It was carried out the characterization of the films obtained by means of UV-vis spectrophotometry, and photoluminescence (FL). The microstructure analysis was carried out by means of X-ray diffraction (XRD), micro-Raman (MR), and atomic force microscopy (AFM). By means of the diffractographs it was determined the grain size. Our results show that in our films they are present the anatase and rutile phases of the titanium dioxide. The analysis of the results of optical spectra shows a forbidden band of the titanium dioxide around 3.2 eV. (Author)

  5. Extended-length fiber optic carbon dioxide monitoring

    Science.gov (United States)

    Delgado-Alonso, Jesus; Lieberman, Robert A.

    2013-05-01

    This paper discusses the design and performance of fiber optic distributed intrinsic sensors for dissolved carbon dioxide, based on the use optical fibers fabricated so that their entire lengths are chemically sensitive. These fibers use a polymer-clad, silica-core structure where the cladding undergoes a large, reversible, change in optical absorbance in the presence of CO2. The local "cladding loss" induced by this change is thus a direct indication of the carbon dioxide concentration in any section of the fiber. To create these fibers, have developed a carbon dioxide-permeable polymer material that adheres well to glass, is physically robust, has a refractive index lower than fused silica, and acts as excellent hosts for a unique colorimetric indicator system that respond to CO2. We have used this proprietary material to produce carbon-dioxide sensitive fibers up to 50 meters long, using commercial optical fiber fabrication techniques. The sensors have shown a measurement range of dissolved CO2 of 0 to 1,450 mg/l (0 to 100% CO2 saturation), limit of detection of 0.3 mg/l and precision of 1.0 mg/l in the 0 to 50 mg/l dissolved CO2 range, when a 5 meter-long sensor fiber segment is used. Maximum fiber length, minimum detectable concentration, and spatial resolution can be adjusted by adjusting indicator concentration and fiber design.

  6. Absorption of carbon dioxide in waste tanks

    International Nuclear Information System (INIS)

    Hobbs, D.T.

    1987-01-01

    Air flow rates and carbon dioxide concentrations of air entering and exiting eight H-Area waste tanks were monitored for a period of one year. The average instanteous concentration of carbon dioxide in air is within the range reported offsite, and therefore is not affect by operation of the coal-fired power plant adjacent to the tank farm. Waste solutions in each of the tanks were observed to be continuously absorbing carbon dioxide. The rate of absorption of carbon dioxide decreased linearly with the pH of the solution. Personnel exposure associated with the routine sampling and analysis of radioactive wastes stored at SRP to determine the levels of corrosion inhibitors in solution could be reduced by monitoring the absorption of carbon dioxide and using the relationship between pH and carbon dioxide absorption to determine the free hydroxide concentration in solution

  7. 21 CFR 184.1240 - Carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Carbon dioxide. 184.1240 Section 184.1240 Food and... Substances Affirmed as GRAS § 184.1240 Carbon dioxide. (a) Carbon dioxide (empirical formula CO2, CAS Reg. No.... The solid form, dry ice, sublimes under atmospheric pressure at a temperature of −78.5 °C. Carbon...

  8. A METHOD OF PREPARING URANIUM DIOXIDE

    Science.gov (United States)

    Scott, F.A.; Mudge, L.K.

    1963-12-17

    A process of purifying raw, in particular plutonium- and fission- products-containing, uranium dioxide is described. The uranium dioxide is dissolved in a molten chloride mixture containing potassium chloride plus sodium, lithium, magnesium, or lead chloride under anhydrous conditions; an electric current and a chlorinating gas are passed through the mixture whereby pure uranium dioxide is deposited on and at the same time partially redissolved from the cathode. (AEC)

  9. Methods and compositions for removing carbon dioxide from a gaseous mixture

    Science.gov (United States)

    Li, Jing; Wu, Haohan

    2014-06-24

    Provided is a method for adsorbing or separating carbon dioxide from a mixture of gases by passing the gas mixture through a porous three-dimensional polymeric coordination compound having a plurality of layers of two-dimensional arrays of repeating structural units, which results in a lower carbon dioxide content in the gas mixture. Thus, this invention provides useful compositions and methods for removal of greenhouse gases, in particular CO.sub.2, from industrial flue gases or from the atmosphere.

  10. Combined effect of sulfur dioxide and carbon dioxide gases on mold fungi

    Energy Technology Data Exchange (ETDEWEB)

    Kochurova, A.I.; Karpova, T.N.

    1974-01-01

    Sulfur dioxide at 0.08% killed Penicillium expansum, Stemphylium macrosporium, and Botrytis cinerea within 24 hours. At 0.2%, it killed P. citrinum, Alternaria tenuis, and Fusarium moniliforme. Sulfur dioxide (at 0.04%) and Sulfur dioxide-carbon dioxide mixtures (at 0.02 and 5% respectively) completely suppressed the growth of P. citrinum, P. expansum, P. rubrum, A. tenuis, S. macrosporium, B. cinerea, and F. moniliforme in laboratory experiments. 1 table.

  11. Experimental nitrogen dioxide poisoning in cattle

    Energy Technology Data Exchange (ETDEWEB)

    Cutlip, R C

    1966-01-01

    Experimental nitrogen dioxide inhalation has been reported to produce signs and lesions typical of field cases of bovine pulmonary adenomatosis (BPA) as described by Monlux et al, and Seaton. Similar lesions have been produced in mice and guinea pigs. These studies were conducted because of the similarities between silo-filler's disease of man, caused by nitrogen dioxide, and BPA. Since previous studies involved inadequate numbers of cattle, a more critical evaluation of the effects of nitrogen dioxide was needed. This project was designed to study the clinical and pathologic alterations induced in cattle by repeated exposure to nitrogen dioxide gas.

  12. Metal-insulator transition in vanadium dioxide

    International Nuclear Information System (INIS)

    Zylbersztejn, A.; Mott, N.F.

    1975-01-01

    The basic physical parameters which govern the metal-insulator transition in vanadium dioxide are determined through a review of the properties of this material. The major importance of the Hubbard intra-atomic correlation energy in determining the insulating phase, which was already evidence by studies of the magnetic properties of V 1 -/subx/Cr/subx/O 2 alloys, is further demonstrated from an analysis of their electrical properties. An analysis of the magnetic susceptibility of niobium-doped VO 2 yields a picture for the current carrier in the low-temperature phase in which it is accompanied by a spin cloud (owing to Hund's-rule coupling), and has therefore an enhanced mass (m approx. = 60m 0 ). Semiconducting vanadium dioxide turns out to be a borderline case for a classical band-transport description; in the alloys at high doping levels, Anderson localization with hopping transport can take place. Whereas it is shown that the insulating phase cannot be described correctly without taking into account the Hubbard correlation energy, we find that the properties of the metallic phase are mainly determined by the band structure. Metallic VO 2 is, in our view, similar to transition metals like Pt or Pd: electrons in a comparatively wide band screening out the interaction between the electrons in a narrow overlapping band. The magnetic susceptibility is described as exchange enhanced. The large density of states at the Fermi level yields a substantial contribution of the entropy of the metallic electrons to the latent heat. The crystalline distortion removes the band degeneracy so that the correlation energy becomes comparable with the band width and a metal-insulator transition takes place

  13. Black Titanium Dioxide Nanomaterials in Photocatalysis

    Directory of Open Access Journals (Sweden)

    Xiaodong Yan

    2017-01-01

    Full Text Available Titanium dioxide (TiO2 nanomaterials are widely considered to be state-of-the-art photocatalysts for environmental protection and energy conversion. However, the low photocatalytic efficiency caused by large bandgap and rapid recombination of photo-excited electrons and holes is a challenging issue that needs to be settled for their practical applications. Structure engineering has been demonstrated to be a highly promising approach to engineer the optical and electronic properties of the existing materials or even endow them with unexpected properties. Surface structure engineering has witnessed the breakthrough in increasing the photocatalytic efficiency of TiO2 nanomaterials by creating a defect-rich or amorphous surface layer with black color and extension of optical absorption to the whole visible spectrum, along with markedly enhanced photocatalytic activities. In this review, the recent progress in the development of black TiO2 nanomaterials is reviewed to gain a better understanding of the structure-property relationship with the consideration of preparation methods and to project new insights into the future development of black TiO2 nanomaterials in photocatalytic applications.

  14. Titanium dioxide nanomaterials for photocatalysis

    International Nuclear Information System (INIS)

    Liu, Yan; Li, Zhe; Green, Michael; Just, Michael; Chen, Xiaobo; Li, Yang Yang

    2017-01-01

    Titanium dioxide (TiO 2 ) has been long regarded as one of the more promising photocatalysts to remove environmental pollution and to generate hydrogen from water under sunlight irradiation via photocatalysis. TiO 2 is environmentally benign and thus is considered a ‘green’ catalyst. In this review we present a short introduction to the physical and electronic properties of TiO 2 , its photocatalytic mechanisms, and some recent examples of various TiO 2 materials used for photocatalysis; these examples include 0, 1, 2, 3D, faceted, defected, composited, and hydrogenated TiO 2 materials. (topical review)

  15. Driving factors behind carbon dioxide emissions in China: A modified production-theoretical decomposition analysis

    International Nuclear Information System (INIS)

    Wang, Qunwei; Chiu, Yung-Ho; Chiu, Ching-Ren

    2015-01-01

    Research on the driving factors behind carbon dioxide emission changes in China can inform better carbon emission reduction policies and help develop a low-carbon economy. As one of important methods, production-theoretical decomposition analysis (PDA) has been widely used to understand these driving factors. To avoid the infeasibility issue in solving the linear programming, this study proposed a modified PDA approach to decompose carbon dioxide emission changes into seven drivers. Using 2005–2010 data, the study found that economic development was the largest factor of increasing carbon dioxide emissions. The second factor was energy structure (reflecting potential carbon), and the third factor was low energy efficiency. Technological advances, energy intensity reductions, and carbon dioxide emission efficiency improvements were the negative driving factors reducing carbon dioxide emission growth rates. Carbon dioxide emissions and driving factors varied significantly across east, central and west China. - Highlights: • A modified PDA used to decompose carbon dioxide emission changes into seven drivers. • Two models were proposed to ameliorate the infeasible occasions. • Economic development was the largest factor of increasing CO_2 emissions in China.

  16. Three-dimensional ordered titanium dioxide-zirconium dioxide film-based microfluidic device for efficient on-chip phosphopeptide enrichment.

    Science.gov (United States)

    Zhao, De; He, Zhongyuan; Wang, Gang; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang

    2016-09-15

    Microfluidic technology plays a significant role in separating biomolecules, because of its miniaturization, integration, and automation. Introducing micro/nanostructured functional materials can improve the properties of microfluidic devices, and extend their application. Inverse opal has a three-dimensional ordered net-like structure. It possesses a large surface area and exhibits good mass transport, making it a good candidate for bio-separation. This study exploits inverse opal titanium dioxide-zirconium dioxide films for on-chip phosphopeptide enrichment. Titanium dioxide-zirconium dioxide inverse opal film-based microfluidic devices were constructed from templates of 270-, 340-, and 370-nm-diameter poly(methylmethacrylate) spheres. The phosphopeptide enrichments of these devices were determined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The device constructed from the 270-nm-diameter sphere template exhibited good comprehensive phosphopeptide enrichment, and was the best among these three devices. Because the size of opal template used in construction was the smallest, the inverse opal film therefore had the smallest pore sizes and the largest surface area. Enrichment by this device was also better than those of similar devices based on nanoparticle films and single component films. The titanium dioxide-zirconium dioxide inverse opal film-based device provides a promising approach for the efficient separation of various biomolecules. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Sulfur Dioxide Analyzer Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Springston, Stephen R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-05-01

    The Sulfur Dioxide Analyzer measures sulfur dioxide based on absorbance of UV light at one wavelength by SO2 molecules which then decay to a lower energy state by emitting UV light at a longer wavelength. Specifically, SO2 + hυ1 →SO2 *→SO2 + hυ2 The emitted light is proportional to the concentration of SO2 in the optical cell. External communication with the analyzer is available through an Ethernet port configured through the instrument network of the AOS systems. The Model 43i-TLE is part of the i-series of Thermo Scientific instruments. The i-series instruments are designed to interface with external computers through the proprietary Thermo Scientific iPort Software. However, this software is somewhat cumbersome and inflexible. Brookhaven National Laboratory (BNL) has written an interface program in National Instruments LabView that both controls the Model 43i-TLE Analyzer AND queries the unit for all measurement and housekeeping data. The LabView vi (the software program written by BNL) ingests all raw data from the instrument and outputs raw data files in a uniform data format similar to other instruments in the AOS and described more fully in Section 6.0 below.

  18. Carbon Dioxide for pH Control

    Energy Technology Data Exchange (ETDEWEB)

    Wagonner, R.C.

    2001-08-16

    Cardox, the major supplier of carbon dioxide, has developed a diffuser to introduce carbon dioxide into a water volume as small bubbles to minimize reagent loss to the atmosphere. This unit is integral to several configurations suggested for treatment to control alkalinity in water streams.

  19. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept

  20. Trading coalbed methane for carbon dioxide

    International Nuclear Information System (INIS)

    Greenberger, L.S.

    1991-01-01

    This article discusses a proposal for reducing methane emissions in coal mining activities and at the same time reducing the burden on utilities to cut carbon dioxide emissions. Emission credits would be issued to mines that recover the methane for use. These credits could then be bought by utilities and exchanged for the right to emit carbon dioxide

  1. Pressure pumping of carbon dioxide from soil

    Science.gov (United States)

    E. S. Takle; J. R. Brandle; R. A. Schmidt; R. Garcia; I. V. Litvina; G. Doyle; X. Zhou; Q. Hou; C. W. Rice; W. J. Massman

    2000-01-01

    Recent interest in atmospheric increases in carbon dioxide have heightened the need for improved accuracy in measurements of fluxes of carbon dioxide from soils. Diffusional movement has long been considered the dominant process by which trace gases move from the subsurface source to the surface, although there has been some indication that atmospheric pressure...

  2. Process for the preparation of uranium dioxide

    International Nuclear Information System (INIS)

    Watt, G.W.; Baugh, D.W. Jr.

    1981-01-01

    A method for the preparation of actinide dioxides using actinide nitrate hexahydrates as starting materials is described. The actinide nitrate hexahydrate is reacted with sodium dithionite, and the product is heated in the absence of oxygen to obtain the dioxide. Preferably, the actinide is uranium, plutonium or neptunium. (LL)

  3. Hemispherical Scanning Imaging DOAS: Resolving nitrogen dioxide in the urban environment

    Science.gov (United States)

    Leigh, R. J.; Graves, R. R.; Lawrence, J.; Faloon, K.; Monks, P. S.

    2012-12-01

    Imaging DOAS techniques have been used for nitrogen dioxide and sulfer dioxide for a number of years. This presentation describes a novel system which images concentrations of nitrogen dioxide by scanning an imaging spectrometer 360 degrees azimuthally, covering a region from 5 degrees below the horizon, to the zenith. The instrument has been built at the University of Leicester (UK), on optical designs by Surrey Satellite Technologies Ltd, and incorporates an Offner relay with Schwarzchild fore-optics, in a rotating mount. The spectrometer offers high fidelity spectroscopic retrievals of nitrogen dioxide as a result of a reliable Gaussian line shape, zero smile and low chromatic aberration. The full hemispherical scanning provides complete coverage of nitrogen dioxide concentrations above approximately 5 ppbv in urban environments. Through the use of multiple instruments, the three-dimensional structure of nitrogen dioxide can be sampled and tomographically reconstructed, providing valuable information on nitrogen dioxide emissions and downwind exposure, in addition to new understanding of boundary layer dynamics through the use of nitrogen dioxide as a tracer. Furthermore, certain aerosol information can be retrieved through absolute intensity measurements in each azimuthal direction supplemented by traditional techniques of O4 spectroscopy. Such measurements provide a new tool for boundary layer measurement and monitoring at a time when air quality implications on human health and climate are under significant scrutiny. This presentation will describe the instrument and tomographic potential of this technique. First measurements were taken as part of the international PEGASOS campaign in Bologna, Italy. Results from these measurements will be shown, including imaging of enhanced NO2 in the Bologna urban boundary layer during a severe thunderstorm. A Hemispherical Scanning Imaging DOAS instrument operating in Bologna, Italy in June 2012. Visible in the background

  4. Nr 470 - Report on the behalf of the Commission of foreign affairs, defence and armed forces on the bill project authorizing the approval of amendments of appendices II and III to the OSPAR convention for the protection of the marine environment of the North-East Atlantic related to the storage of carbon dioxide fluxes in geological structures

    International Nuclear Information System (INIS)

    Aichi, Leila

    2013-01-01

    This report first discusses the necessity to protect the marine environment of the north-east Atlantic Ocean. It briefly recalls the content and objectives of the OSPAR convention, and outlines the need of a permanent update of this convention to take measures of struggle against climate change into account. Notably, two amendments introduced the interdiction of storage of carbon dioxide fluxes. It highlights the need to protect the Arctic Ocean area. In a second part, the report discusses the emergence of a new technique for the storage of CO 2 (the injection in geological structures), and shows that this technique complies with the objective of struggle against climate change. However, the authors also mention the worrying potential risk for the ecosystem, and the fact that this technique should complement but not replace other measures against climate change

  5. Reaction mechanisms for enhancing carbon dioxide mineral sequestration

    Science.gov (United States)

    Jarvis, Karalee Ann

    Increasing global temperature resulting from the increased release of carbon dioxide into the atmosphere is one of the greatest problems facing society. Nevertheless, coal plants remain the largest source of electrical energy and carbon dioxide gas. For this reason, researchers are searching for methods to reduce carbon dioxide emissions into the atmosphere from the combustion of coal. Mineral sequestration of carbon dioxide reacted in electrolyte solutions at 185°C and 2200 psi with olivine (magnesium silicate) has been shown to produce environmentally benign carbonates. However, to make this method feasible for industrial applications, the reaction rate needs to be increased. Two methods were employed to increase the rate of mineral sequestration: reactant composition and concentration were altered independently in various runs. The products were analyzed with complete combustion for total carbon content. Crystalline phases in the product were analyzed with Debye-Scherrer X-ray powder diffraction. To understand the reaction mechanism, single crystals of San Carlos Olivine were reacted in two solutions: (0.64 M NaHCO3/1 M NaCl) and (5.5 M KHCO3) and analyzed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and fluctuation electron microscopy (FEM) to study the surface morphology, atomic crystalline structure, composition and amorphous structure. From solution chemistry studies, it was found that increasing the activity of the bicarbonate ion increased the conversion rate of carbon dioxide to magnesite. The fastest conversion, 60% conversion in one hour, occurred in a solution of 5.5 M KHCO3. The reaction product particles, magnesium carbonate, significantly increased in both number density and size on the coupon when the bicarbonate ion activity was increased. During some experiments reaction vessel corrosion also altered the mineral sequestration mechanism. Nickel ions from vessel

  6. Carbon dioxide production in animal houses

    DEFF Research Database (Denmark)

    Pedersen, Søren; Blanes-Vidal, Victoria; Joergensen, H.

    2008-01-01

    cellars are emptied regularly in a four weeks interval. Due to a high and variable carbon dioxide production in deep straw litter houses and houses with indoor storage of manure longer than four weeks, we do not recommend to calculate the ventilation flow based on the carbon dioxide concentration......This article deals with carbon dioxide production from farm animals; more specifically, it addresses the possibilities of using the measured carbon dioxide concentration in animal houses as basis for estimation of ventilation flow (as the ventilation flow is a key parameter of aerial emissions from...... animal houses). The investigations include measurements in respiration chambers and in animal houses, mainly for growing pigs and broilers. Over the last decade a fixed carbon dioxide production of 185 litres per hour per heat production unit, hpu (i.e. 1000 W of the total animal heat production at 20o...

  7. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    equilibrium and associated property models are used. Simulations are performed to investigate the sensitivity of the process variables to change in the design variables including process inputs and disturbances in the property model parameters. Results of the sensitivity analysis on the steady state...... performance of the process to the L/G ratio to the absorber, CO2 lean solvent loadings, and striper pressure are presented in this paper. Based on the sensitivity analysis process optimization problems have been defined and solved and, a preliminary control structure selection has been made.......Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  8. Conformational and structural analysis of 2-allyl-1,2-benzisothiazol-3(2 H)-one 1,1-dioxide as probed by matrix-isolation spectroscopy and quantum chemical calculations

    Science.gov (United States)

    Gómez-Zavaglia, Andrea; Kaczor, Agnieszka; Coelho, Daniela; Cristiano, M. Lurdes S.; Fausto, Rui

    2009-02-01

    2-Allyl-1,2-benzisothiazol-3(2 H)-one 1,1-dioxide (ABIOD) has been studied by matrix-isolation infrared spectroscopy and quantum chemical calculations. A conformational search on the B3LYP/6 -311++G(3df,3pd) potential energy surface of the molecule demonstrated the existence of three conformers, Sk, Sk' and C, with similar energies, differing in the orientation of the allyl group. The calculations predicted the Sk form as the most stable in the gaseous phase, whereas the Sk' and C conformers have calculated relative energies of ca. 0.6 and 0.8-3.0 kJ mol -1, respectively (depending on the level of theory). In agreement with the relatively large (>6 kJ mol -1) calculated barriers for conformational interconversion, the three conformers could be efficiently trapped in an argon matrix at 10 K, the experimental infrared spectrum of the as-deposited matrix fitting well the simulated spectrum built from the calculated spectra for individual conformers scaled by their predicted populations at the temperature of the vapour of the compound prior to matrix deposition. Upon annealing the matrix at 24 K, however, both Sk and Sk' conformers were found to convert to the more polar C conformer, indicating that this latter form becomes the most stable ABIOD conformer in the argon matrix.

  9. Forest response to carbon dioxide

    International Nuclear Information System (INIS)

    Pitelka, L.

    1992-01-01

    It has been suggested that planting trees could help slow the buildup of carbon dioxide in the atmosphere. Since elevated levels of CO 2 are known to enhance photosynthesis and growth in many plants, it is possible that trees could become progressively more effective in storing carbon as atmospheric CO 2 increases. However, early results from experiments with ponderosa and loblolly pines indicate that the relationship between tree growth and rising CO 2 concentrations may be more complex than scientists once thought. In these experiments, the response to elevated CO 2 has been highly dependent both on species and on mineral nutrient levels in the soil. Further work is necessary to clarify the mechanisms involved. This research will ultimately contribute to an integrated model for predicting forest ecosystem response to elevated CO 2

  10. Electrochemical processing of carbon dioxide.

    Science.gov (United States)

    Oloman, Colin; Li, Hui

    2008-01-01

    With respect to the negative role of carbon dioxide on our climate, it is clear that the time is ripe for the development of processes that convert CO(2) into useful products. The electroreduction of CO(2) is a prime candidate here, as the reaction at near-ambient conditions can yield organics such as formic acid, methanol, and methane. Recent laboratory work on the 100 A scale has shown that reduction of CO(2) to formate (HCO(2)(-)) may be carried out in a trickle-bed continuous electrochemical reactor under industrially viable conditions. Presuming the problems of cathode stability and formate crossover can be overcome, this type of reactor is proposed as the basis for a commercial operation. The viability of corresponding processes for electrosynthesis of formate salts and/or formic acid from CO(2) is examined here through conceptual flowsheets for two process options, each converting CO(2) at the rate of 100 tonnes per day.

  11. Nongovernmental valorization of carbon dioxide

    International Nuclear Information System (INIS)

    Petersen, Gene; Viviani, Donn; Magrini-Bair, Kim; Kelley, Stephen; Moens, Luc; Shepherd, Phil; DuBois, Dan

    2005-01-01

    Carbon dioxide (CO 2 ) is considered the largest contributor to the greenhouse gas effect. Most attempts to manage the flow of CO 2 or carbon into our environment involve reducing net emissions or sequestering the gas into long-lived sinks. Using CO 2 as a chemical feedstock has a long history, but using it on scales that might impact the net emissions of CO 2 into the atmosphere has not generally been considered seriously. There is also a growing interest in employing our natural biomes of carbon such as trees, vegetation, and soils as storage media. Some amelioration of the net carbon emissions into the atmosphere could be achieved by concomitant large withdrawals of carbon. This report surveys the potential and limitations in employing carbon as a resource for organic chemicals, fuels, inorganic materials, and in using the biome to manage carbon. The outlook for each of these opportunities is also described

  12. Erbium diffusion in titanium dioxide

    Directory of Open Access Journals (Sweden)

    Louise Basse

    2017-04-01

    Full Text Available The diffusivity of erbium in the anatase phase of titanium dioxide (TiO2 has been studied for various temperatures ranging from 800 °C to 1, 000 °C. Samples of TiO2, with a 10 nm thick buried layer containing 0.5 at% erbium, were fabricated by radio-frequency magnetron sputtering and subsequently heat treated. The erbium concentration profiles were measured by secondary ion mass spectrometry, allowing for determination of the temperature-dependent diffusion coefficients. These were found to follow an Arrhenius law with an activation energy of ( 2.1 ± 0.2 eV. X-ray diffraction revealed that the TiO2 films consisted of polycrystalline grains of size ≈ 100 nm.

  13. Carbon dioxide cleaning pilot project

    International Nuclear Information System (INIS)

    Knight, L.; Blackman, T.E.

    1994-01-01

    In 1989, radioactive-contaminated metal at the Rocky Flats Plant (RFP) was cleaned using a solvent paint stripper (Methylene chloride). One-third of the radioactive material was able to be recycled; two-thirds went to the scrap pile as low-level mixed waste. In addition, waste solvent solutions also required disposal. Not only was this an inefficient process, it was later prohibited by the Resource Conservation and Recovery Act (RCRA), 40 CFR 268. A better way of doing business was needed. In the search for a solution to this situation, it was decided to study the advantages of using a new technology - pelletized carbon dioxide cleaning. A proof of principle demonstration occurred in December 1990 to test whether such a system could clean radioactive-contaminated metal. The proof of principle demonstration was expanded in June 1992 with a pilot project. The purpose of the pilot project was three fold: (1) to clean metal so that it can satisfy free release criteria for residual radioactive contamination at the Rocky Flats Plant (RFP); (2) to compare two different carbon dioxide cleaning systems; and (3) to determine the cost-effectiveness of decontamination process in a production situation and compare the cost of shipping the metal off site for waste disposal. The pilot project was completed in August 1993. The results of the pilot project were: (1) 90% of those items which were decontaminated, successfully met the free release criteria , (2) the Alpheus Model 250 was selected to be used on plantsite and (3) the break even cost of decontaminating the metal vs shipping the contaminated material offsite for disposal was a cleaning rate of 90 pounds per hour, which was easily achieved

  14. Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Qureshi, Uzma; Dunnill, Charles W.; Parkin, Ivan P.

    2009-01-01

    Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)-nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO 2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

  15. Surface characterisation and electrochemical behaviour of porous titanium dioxide coated 316L stainless steel for orthopaedic applications

    International Nuclear Information System (INIS)

    Nagarajan, S.; Rajendran, N.

    2009-01-01

    Porous titanium dioxide was coated on surgical grade 316L stainless steel (SS) and its role on the corrosion protection and enhanced biocompatibility of the materials was studied. X-ray diffraction analysis (XRD), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were carried out to characterise the surface morphology and also to understand the structure of the as synthesised coating on the substrates. The corrosion behaviour of titanium dioxide coated samples in simulated body fluid was evaluated using polarisation and impedance spectroscopy studies. The results reveal that the titanium dioxide coated 316L SS exhibit a higher corrosion resistance than the uncoated 316L SS. The titanium dioxide coated surface is porous, uniform and also it acts as a barrier layer to metallic substrate and the porous titanium dioxide coating induces the formation of hydroxyapatite layer on the metal surface.

  16. Somewhere beyond the sea? The oceanic - carbon dioxide - reactions

    Science.gov (United States)

    Meisinger, Philipp; Wittlich, Christian

    2014-05-01

    In correlation to climate change and CO2 emission different campaigns highlight the importance of forests and trees to regulate the concentration of carbon dioxide in the earths' atmosphere. Seeing millions of square miles of rainforest cut down every day, this is truly a valid point. Nevertheless, we often tend to forget what scientists like Spokes try to raise awareness for: The oceans - and foremost deep sea sections - resemble the second biggest deposit of carbon dioxide. Here carbon is mainly found in form of carbonate and hydrogen carbonate. The carbonates are needed by corals and other sea organisms to maintain their skeletal structure and thereby to remain vital. To raise awareness for the protection of this fragile ecosystem in schools is part of our approach. Awareness is achieved best through understanding. Therefore, our approach is a hands-on activity that aims at showing students how the carbon dioxide absorption changes in relation to the water temperature - in times of global warming a truly sensitive topic. The students use standard syringes filled with water (25 ml) at different temperatures (i.e. 10°C, 20°C, 40°C). Through a connector students inject carbon dioxide (25ml) into the different samples. After a fixed period of time, students can read of the remaining amount of carbon dioxide in relation to the given water temperature. Just as with every scientific project, students need to closely monitor their experiments and alter their setups (e.g. water temperature or acidity) according to their initial planning. A digital template (Excel-based) supports the analysis of students' experiments. Overview: What: hands-on, minds -on activity using standard syringes to exemplify carbon dioxide absorption in relation to the water temperature (Le Chatelier's principle) For whom: adjustable from German form 11-13 (age: 16-19 years) Time: depending on the prior knowledge 45-60 min. Sources (extract): Spokes, L.: Wie Ozeane CO2 aufnehmen. Environmental

  17. Surface Characterization and Electrochemical Oxidation of Metal Doped Uranium Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeongmook; Kim, Jandee; Youn, Young-Sang; Kim, Jong-Goo; Ha, Yeong-Keong; Kim, Jong-Yun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Trivalent element in UO{sub 2} matrix makes the oxygen vacancy from loss of oxygen for charge compensation. Tetravalent element alters lattice parameter of UO{sub 2} due to diameter difference between the tetravalent element and replaced U. These structural changes have significant effect on not only relevant fuel performance but also the kinetics of fuel oxidation. Park and Olander explained the stabilization of Ln (III)-doped UO{sub 2} against oxidation based on oxygen potential calculations. In this work, we have been investigated the effect of Gd{sup 3+} and Th{sup 4+} doping on the UO{sub 2} structure with Raman spectroscopy and X-ray diffraction to characterize the surface structure of nuclear fuel material. For Gd doped UO{sub 2}, its electrochemical oxidation behaviors are also investigated. The Gd and Th doped uranium dioxide solid solution pellets with various doping level were investigated by XRD, Raman spectroscopy, SEM, electrochemical experiments to investigate surface structure and electro chemical oxidation behaviors. The lattice parameter evaluated from XRD spectra indicated the formation of solid solutions. Raman spectra showed the existence of the oxygen vacancy. SEM images showed the grain structure on the surface of Gd doped uranium dioxide depending on doping level and oxygen-to-metal ratio.

  18. Reaction of yttrium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Khokhlov, A.D.; Reznikova, N.F.

    1986-01-01

    It has been proved that heating of yttrium and tantalum in carbon dioxide to 500 and 800 0 C alters the gas phase composition, causing formation of carbon monoxide and reduction of oxygen content. A study of the thermal stability of yttrium polonides in carbon dioxide showed that yttrium sesqui- and monopolonides decompose at 400-430 0 C. The temperature dependence of the vapor pressure of polonium obtained upon decomposition of the referred polonides has been determined in a carbon dioxide environment radiotensometrically. The enthalpy of the process calculated from this dependence is close to the enthalpy of vaporization of elemental polonium in vacuo. The mechanism of the reactions has been suggested

  19. Regional sulfur dioxide emissions: shall we achieve the goal?

    Science.gov (United States)

    Tan, X.; Shi, L.; Wang, M.; Wang, JY

    2017-01-01

    Although economic growth is slowing down in the new normal period, air pollution is still a very serious problem in China. The 15% binding goal of sulfur dioxide emission reduction from 2016 to 2020, as stipulated in the 13th Five-Year Plan, has been an ambitious target for the Chinese government. This paper studies the synthetic evaluation and forecasting analysis of sulfur dioxide in China by means of a “grey model” approach combined with the grey relational analysis methods, with the panel data of 31 provinces from 2005 to 2015. Grey analysis used to analyse a system with imperfect information, such that a variety of available solutions is reviewed, and the optimal solution is identified. Some encouraging results show that national emissions and a majority of provinces will achieve the target. Over time, the gap of regional differences is rapidly closing. According to the results of grey relational analysis, we find industrial structure and energy consumption have a more significant impact on sulfur dioxide emissions than GDP. Atmospheric treatment investment and environmental protection manpower play a more important role in emissions variation. Based on the findings, we should distinguish different factors and take different measures to protect the environment.

  20. Nanomaterial Case Studies: Nanoscale Titanium Dioxide ...

    Science.gov (United States)

    This draft document presents two case studies of nanoscale titanium dioxide (nano-TiO2) used (1) to remove arsenic from drinking water and (2) as an active ingredient in topical sunscreen. The draft case studies are organized around a comprehensive environmental assessment approach that combines a product life cycle framework with the risk assessment paradigm. The document does not draw conclusions about potential risks. Rather, the case studies are intended to help identify what needs to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. This draft document is part of a process that will inform the development of EPA’s research strategy to support nanomaterial risk assessments. The complex properties of various nanomaterials make evaluating them in the abstract or with generalizations difficult if not impossible. Thus, this document focuses on two specific uses of nano-TiO2, as a drinking water treatment and as topical sunscreen. These case studies do not represent completed or even preliminary assessments; rather, they present the structure for identifying and prioritizing research needed to support future assessments.

  1. 46 CFR 97.37-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Carbon dioxide alarm. 97.37-9 Section 97.37-9 Shipping... Markings for Fire and Emergency Equipment, Etc. § 97.37-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING...

  2. 46 CFR 78.47-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Carbon dioxide alarm. 78.47-9 Section 78.47-9 Shipping... and Emergency Equipment, Etc. § 78.47-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED.” (b) [Reserved] ...

  3. 46 CFR 169.732 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Carbon dioxide alarm. 169.732 Section 169.732 Shipping... Control, Miscellaneous Systems, and Equipment Markings § 169.732 Carbon dioxide alarm. Each carbon dioxide alarm must be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED.” ...

  4. 46 CFR 196.37-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Carbon dioxide alarm. 196.37-9 Section 196.37-9 Shipping... Markings for Fire and Emergency Equipment, etc. § 196.37-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING...

  5. 46 CFR 108.627 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Carbon dioxide alarm. 108.627 Section 108.627 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.627 Carbon dioxide alarm. Each carbon dioxide alarm must be identified by marking: “WHEN ALARM SOUNDS VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED” next to...

  6. Sequestering carbon dioxide in industrial polymers: Building materials for the 21st century

    Energy Technology Data Exchange (ETDEWEB)

    Molton, P.M.; Nelson, D.A.

    1993-06-01

    This study was undertaken to determine the possibility of developing beneficial uses for carbon dioxide as a key component for a large-volume building product. Such a use may provide an alternative to storing the gas in oceanic sinks or clathrates as a way to slow the rate of global warming. The authors investigated the concept that carbon dioxide might be used with other chemicals to make carbon-dioxide-based polymers which would be lightweight, strong, and economical alternatives to some types of wood and silica-based building materials. As a construction-grade material, carbon dioxide would be fixed in a solid, useful form where it would not contribute to global warming. With the probable imposition of a fuel carbon tax in industrialized countries, this alternative would allow beneficial use of the carbon dioxide and could remove it from the tax basis if legislation were structured appropriately. Hence, there would be an economic driver towards the use of carbon-dioxide-based polymers which would enhance their future applications. Information was obtained through literature searches and personal contacts on carbon dioxide polymers which showed that the concept (1) is technically feasible, (2) is economically defensible, and (3) has an existing industrial infrastructure which could logically develop it. The technology exists for production of building materials which are strong enough for use by industry and which contain up to 90% by weight of carbon dioxide, both chemically and physically bound. A significant side-benefit of using this material would be that it is self-extinguishing in case of fire. This report is the first stage in the investigation. Further work being proposed will provide details on costs, specific applications and volumes, and potential impacts of this technology.

  7. Novel Antimicrobial Titanium Dioxide Nanotubes Obtained through a Combination of Atomic Layer Deposition and Electrospinning Technologies

    Science.gov (United States)

    Patiño, Cristian; Galotto, María Jose; Palma, Juan Luis; Alburquenque, Daniela

    2018-01-01

    The search for new antimicrobial substances has increased in recent years. Antimicrobial nanostructures are one of the most promising alternatives. In this work, titanium dioxide nanotubes were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers (PVN) at different temperatures with the purpose of obtaining antimicrobial nanostructures with a high specific area. Electrospinning and ALD parameters were studied in order to obtain PVN with smallest diameter and highest deposition rate, respectively. Chamber temperature was a key factor during ALD process and an appropriate titanium dioxide deposition performance was achieved at 200 °C. Subsequently, thermal and morphological analysis by SEM and TEM microscopies revealed hollow nanotubes were obtained after calcination process at 600 °C. This temperature allowed complete polymer removal and influenced the resulting anatase crystallographic structure of titanium dioxide that positively affected their antimicrobial activities. X-ray analysis confirmed the change of titanium dioxide crystallographic structure from amorphous phase of deposited PVN to anatase crystalline structure of nanotubes. These new nanostructures with very large surface areas resulted in interesting antimicrobial properties against Gram-positive and Gram-negative bacteria. Titanium dioxide nanotubes presented the highest activity against Escherichia coli with 5 log cycles reduction at 200 μg/mL concentration. PMID:29495318

  8. Theoretical study of carbon dioxide adsorption and diffusion in MIL-127(Fe) metal organic framework

    Science.gov (United States)

    Pongsajanukul, Pavee; Parasuk, Vudhichai; Fritzsche, Siegfried; Assabumrungrat, Suttichai; Wongsakulphasatch, Suwimol; Bovornratanaraks, Thiti; Chokbunpiam, Tatiya

    2017-07-01

    The UFF force field is found to reproduce the adsorption isotherm of carbon dioxide in MIL-127(Fe) well. It has therefore been used to investigate the structure and self-diffusion of carbon dioxide molecules in the MIL which is a candidate for membrane or adsorption application. The structure of the adsorbed phase shows different regions of high concentration. The highest particle concentration was found in the central regions of the channels. The self-diffusion coefficient slightly increases with the loading for low concentration of guest molecules while for higher concentrations it decreases because of mutual hindrance of guest molecules.

  9. Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water

    International Nuclear Information System (INIS)

    Nakajima, Hayato; Imai, Yoshiyuki; Kasahara, Seiji; Kubo, Shinji; Onuki, Kaoru

    2007-01-01

    Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water, which is a unit reaction in the IS process for thermochemical hydrogen production, was studied experimentally at 323 K under iodine saturation. Quasi-equilibrium state was observed in the presence of sulfur dioxide gas at constant pressure. The composition of the poly-hydriodic acid solution formed was discussed assuming an ideal desulfurization by the reverse reaction of the Bunsen reaction. The value of HI/(HI+H 2 O) of the desulfurized solution was large at high sulfur dioxide pressure and reached the maximum of 15.7 ± 0.3 mol%. (author)

  10. Carbon dioxide: making the right connection

    African Journals Online (AJOL)

    This highlights safety issues concerning pipeline provision of carbon dioxide, and that it is of utmost ... capnograph sample line, gas analysis unit, water trap and soda .... The heat generated by the chemical reaction between soda lime.

  11. Electrochemical reduction of sulfur dioxide in sulfolane

    Energy Technology Data Exchange (ETDEWEB)

    Vorob' ev, A.S.; Gavrilova, A.A.; Kolosnitsyn, V.S.; Nikitin, Yu.E.

    1985-09-01

    Solutions of sulfur dioxide in aproptic media are promising electrolyte oxidizing agents for chemical current sources with anodes of active metals. This work describes the electrochemical reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte which was investigated by the methods of voltamperometry and chronopotentiometry. The dependence of the current of the cathodic peak on the concentration of the supporting electrolyte salts, sulfur dioxide and water, was studied. On the basis of the data obtained, a hypothesis was advanced on the nature of the limiting step. The investigation showed that at low polarizing current densities, a substantial influence on the reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte is exerted by blockage of the electrode surface by sparingly soluble reaction products.

  12. integrated vertical photobioreactor system for carbon dioxide

    African Journals Online (AJOL)

    Astri Nugroho

    2013-07-02

    Jul 2, 2013 ... efficient system for converting carbon dioxide (CO2) into biomass. The use of ... often been thought to achieve the most efficient mixing and the best ... such process a photobioreactor is designed. Photobioreactor is a device ...

  13. Technology of getting of microspheric thorium dioxide

    International Nuclear Information System (INIS)

    Balakhonov, V.G.; Matyukha, V.A.; Saltan, N.P.; Filippov, E.A.; Zhiganov, A.N.

    1999-01-01

    There has been proposed a technique for getting granulated thorium dioxide from its salts solutions according to the cryogenic technology by the method of a solid phase conversion. It includes the following operations: dispersion of the initial solution into liquid nitrogen and getting of cryogranules of the necessary size by putting oscillations of definite frequency on a die device and by charging formed drops in the constant electric field; solid phase conversion of thorium salts into its hydroxide by treating cryogranules with a cooled ammonia solution, drying and calcination of hydroxide granules having got granulated thorium dioxide. At the pilot facility there have been defined and developed optimum regimes for getting granulated thorium dioxide. The mechanism of thorium hydroxide cryogranules conversion into thorium dioxide was investigated by the thermal analysis methods. (author)

  14. Antipollution system to remove nitrogen dioxide gas

    Science.gov (United States)

    Metzler, A. J.; Slough, J. W.

    1971-01-01

    Gas phase reaction system using anhydrous ammonia removes nitrogen dioxide. System consists of ammonia injection and mixing section, reaction section /reactor/, and scrubber section. All sections are contained in system ducting.

  15. Doped titanium dioxide nanocrystalline powders with high photocatalytic activity

    International Nuclear Information System (INIS)

    Castro, A.L.; Nunes, M.R.; Carvalho, M.D.; Ferreira, L.P.; Jumas, J.-C.; Costa, F.M.; Florencio, M.H.

    2009-01-01

    Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with anatase structure were successfully synthesized through an hydrothermal route preceded by a precipitation doping step. Structural and morphological characterizations were performed by powder XRD and TEM. Thermodynamic stability studies allowed to conclude that the anatase structure is highly stable for all doped TiO 2 prepared compounds. The photocatalytic efficiency of the synthesized nanopowders was tested and the results showed an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 , whereas no photocatalytic activity was detected for the Fe:TiO 2 and Co:TiO 2 nanopowders. These results were correlated to the doping ions oxidation states, determined by Moessbauer spectroscopy and magnetization data. - Graphical abstract: Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with highly stable anatase structure were successfully synthesized through an hydrothermal route. The photocatalytic efficiencies of the synthesized nanopowders were tested and the results show an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 .

  16. Thorium dioxide: properties and nuclear applications

    International Nuclear Information System (INIS)

    Belle, J.; Berman, R.M.

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core

  17. Thorium dioxide: properties and nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Belle, J.; Berman, R.M. (eds.)

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

  18. Supercritical carbon dioxide hop extraction

    Directory of Open Access Journals (Sweden)

    Pfaf-Šovljanski Ivana I.

    2005-01-01

    Full Text Available The hop of Magnum cultivar was extracted using supercritical carbon dioxide (SFE-as extractant. Extraction was carried out in the two steps: the first one being carried out at 150 bar and 40°C for 2.5 h (Extract A, and the second was the extraction of the same hop sample at 300 bar and 40°C for 2.5 h (Extract B. Extraction kinetics of the system hop-SFE-CO2 was investigated. Two of four most common compounds of hop aroma (α-humulene and β-caryophyllene were detected in Extract A. Isomerised α-acids and β-acids were detected too. a-Acid content in Extract B was high (that means it is a bitter variety of hop. Mathematical modeling using empirical model characteristic time model and simple single sphere model has been performed on Magnum cultivar extraction experimental results. Characteristic time model equations, best fitted experimental results. Empirical model equation, fitted results well, while simple single sphere model equation poorly approximated the results.

  19. Local structure reconstruction in hydrogenated amorphous silicon from angular correlation and synchrotron diffraction studies

    International Nuclear Information System (INIS)

    Britton, D.T.; Minani, E.; Knoesen, D.; Schut, H.; Eijt, S.W.H.; Furlan, F.; Giles, C.; Haerting, M.

    2006-01-01

    Hydrogenated amorphous silicon (a-Si:H) is a widely used thin film semiconductor material which is still incompletely understood. It is generally assumed to form a continuous random network, with a high concentration of coordination defects (dangling bonds), which are hydrogen terminated. Neither the exact nature of these sites nor the degree of medium range order has been fully determined. In this paper, we present the first results for the local structure, from a combined study using angular correlation of positron annihilation radiation (ACAR) and synchrotron radiation diffraction. Reciprocal space information is obtained directly, for the mesoscale structure and the local defect structure, from the orientation dependent diffraction and 2D-ACAR patterns, respectively. Furthermore, inversion of both patterns yields a comparison of real space information through maps of the silicon-silicon pair correlation function and the electron-positron autocorrelation function B 2γ (r). From this information, it is possible to identify the dominant structural defect as a vacancy-size dangling bond cluster, around which the network strain is fully relaxed

  20. Geographical Detector Model for Influencing Factors of Industrial Sector Carbon Dioxide Emissions in Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Rina Wu

    2016-02-01

    Full Text Available Studying the influencing factors of carbon dioxide emissions is not only practically but also theoretically crucial for establishing regional carbon-reduction policies, developing low-carbon economy and solving the climate problems. Therefore, we used a geographical detector model which is consists of four parts, i.e., risk detector, factor detector, ecological detector and interaction detector to analyze the effect of these social economic factors, i.e., GDP, industrial structure, urbanization rate, economic growth rate, population and road density on the increase of energy consumption carbon dioxide emissions in industrial sector in Inner Mongolia northeast of China. Thus, combining with the result of four detectors, we found that GDP and population more influence than economic growth rate, industrial structure, urbanization rate and road density. The interactive effect of any two influencing factors enhances the increase of the carbon dioxide emissions. The findings of this research have significant policy implications for regions like Inner Mongolia.

  1. Effects of sulfur dioxide pollution on bark epiphytes

    Energy Technology Data Exchange (ETDEWEB)

    Coker, P D

    1967-01-01

    The destructive effects of sulfur dioxide pollution on epiphytic bryophytes is seen to be due to chlorophyll degradation and the impairment of cell structure and function through plasmolysis. Morphological changes noted by Pearson and Skye (1965) in lichens were not seen, although stunting and infertility are evident in epiphyte remnants in polluted areas. The investigation of the ion exchange and buffer capacities of sycamore bark indicates a loss of both in approximate proportion to the degree of pollution. Smoke and aerosol particles are not considered to be of particular importance at the present time although they may well have been important in the past.

  2. Random Surface Texturing of Silicon Dioxide Using Gold Agglomerates

    Science.gov (United States)

    2016-07-01

    a visual indicator of the formation of gold clusters on the SiO2 . The glass would make observing a color change in the gold film easier later in the...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT A fabrication process for creating a silicon dioxide ( SiO2 ) light-trapping structure as part of...even distribution of irregular agglomerates, also known as “complete islanding”. By using these gold agglomerations as a metal mask, the SiO2 can be

  3. A Review of Carbon Dioxide Selective Membranes: A Topical Report

    Energy Technology Data Exchange (ETDEWEB)

    Dushyant Shekhawat; David R. Luebke; Henry W. Pennline

    2003-12-01

    Carbon dioxide selective membranes provide a viable energy-saving alternative for CO2 separation, since membranes do not require any phase transformation. This review examines various CO2 selective membranes for the separation of CO2 and N2, CO2 and CH4, and CO2 and H2 from flue or fuel gas. This review attempts to summarize recent significant advances reported in the literature about various CO2 selective membranes, their stability, the effect of different parameters on the performance of the membrane, the structure and permeation properties relationships, and the transport mechanism applied in different CO2 selective membranes.

  4. Understanding the carbon dioxide gaps.

    Science.gov (United States)

    Scheeren, Thomas W L; Wicke, Jannis N; Teboul, Jean-Louis

    2018-06-01

    The current review attempts to demonstrate the value of several forms of carbon dioxide (CO2) gaps in resuscitation of the critically ill patient as monitor for the adequacy of the circulation, as target for fluid resuscitation and also as predictor for outcome. Fluid resuscitation is one of the key treatments in many intensive care patients. It remains a challenge in daily practice as both a shortage and an overload in intravascular volume are potentially harmful. Many different approaches have been developed for use as target of fluid resuscitation. CO2 gaps can be used as surrogate for the adequacy of cardiac output (CO) and as marker for tissue perfusion and are therefore a potential target for resuscitation. CO2 gaps are easily measured via point-of-care analysers. We shed light on its potential use as nowadays it is not widely used in clinical practice despite its potential. Many studies were conducted on partial CO2 pressure differences or CO2 content (cCO2) differences either alone, or in combination with other markers for outcome or resuscitation adequacy. Furthermore, some studies deal with CO2 gap to O2 gap ratios as target for goal-directed fluid therapy or as marker for outcome. CO2 gap is a sensitive marker of tissue hypoperfusion, with added value over traditional markers of tissue hypoxia in situations in which an oxygen diffusion barrier exists such as in tissue oedema and impaired microcirculation. Venous-to-arterial cCO2 or partial pressure gaps can be used to evaluate whether attempts to increase CO should be made. Considering the potential of the several forms of CO2 measurements and its ease of use via point-of-care analysers, it is recommendable to implement CO2 gaps in standard clinical practice.

  5. Graphite suspension in carbon dioxide

    International Nuclear Information System (INIS)

    Roche, R.

    1965-01-01

    Since 1963 the Atomic Division of SNECMA has been conducting, under a contract with the CEA, an experimental work with a two-component fluid comprised of carbon dioxide and small graphite particles. The primary purpose was the determination of basic engineering information pertaining to the stability and the flowability of the suspension. The final form of the experimental loop consists mainly of the following items: a light-phase compressor, a heavy-phase pump, an electrical-resistance type heater section, a cooling heat exchanger, a hairpin loop, a transparent test section and a separator. During the course of the testing, it was observed that the fluid could be circulated quite easily in a broad range of variation of the suspension density and velocity - density from 30 to 170 kg/m 3 and velocity from 2 to 24 m/s. The system could be restarted and circulation maintained without any difficulty, even with the heavy-phase pump alone. The graphite did not have a tendency to pack or agglomerate during operation. No graphite deposition was observed on the wall of the tubing. A long period run (250 hours) has shown the evolution of the particle dimensions. Starting with graphite of surface area around 20 m 2 /g (graphite particles about 1 μ), the powder surface area reaches an asymptotic value of 300 m 2 /g (all the particles less than 0.3 μ). Moisture effect on flow stability, flow distribution between two parallel channels, pressure drop in straight tubes, recompression ratio in diffusers were also investigated. (author) [fr

  6. Characterisation of chemically lithiated heat-treated electrolytic manganese dioxide

    International Nuclear Information System (INIS)

    Dose, Wesley M.; Lehr, Joshua; Donne, Scott W.

    2012-01-01

    Highlights: ► Manganese oxides are a promising cathode material for lithium ion batteries. Here we examine the structural and morphological changes that occur upon reduction, and assess its impact on material performance. ► Upon reduction, MnO 2 transforms into LiMn 2 O 4 , which is subsequently reduced to Li 2 Mn 2 O 4 . ► Significant morphological changes occur, particularly to the material porosity. ► This transformation for MnO 2 has not been reported previously. -- Abstract: Heat treated manganese dioxide is partially lithiated using butyl-lithium to determine the changes in crystal structure, chemical composition and morphology upon reduction, as a means of simulating its discharge behaviour in a non-aqueous battery cathode. As reduction proceeds, and lithium ions are inserted into the heat treated electrolytic manganese dioxide (EMD) structure, the material undergoes a phase transition to LiMn 2 O 4 . This new phase is further reduced to Li 2 Mn 2 O 4 . Reduction initially results in a 56% decrease in the surface area of the material; however, at higher degrees of reduction a slight increase in this value is observed, as a consequence of the strain placed on the lattice through continued lithium insertion.

  7. Chemoselective alternating copolymerization of limonene dioxide and carbon dioxide : a new highly functional aliphatic epoxy polycarbonate

    NARCIS (Netherlands)

    Li, C.; Sablong, R.J.; Koning, C.E.

    The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg) up

  8. Process for the preparation of uranium dioxide

    International Nuclear Information System (INIS)

    Watt, G.W.; Baugh, D.W. Jr.

    1977-01-01

    An actinide dioxide, e.g., uranium dioxide, plutonium dioxide, neptunium dioxide, etc., is prepared by reacting the actinide nitrate hexahydrate with sodium dithionite as a first step; the reaction product from this first step is a novel composition of matter comprising the actinide sulfite tetrahydrate. The reaction product resulting from this first step is then converted to the actinide dioxide by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) to a temperature of about 500 0 to about 950 0 C for about 15 to about 135 minutes. If the reaction product resulting from the first step is, prior to carrying out the second heating step, exposed to an oxygen-containing atmosphere such as air, the resultant product is a novel composition of matter comprising the actinide oxysulfite tetrahydrate which can also be readily converted to the actinide dioxide by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) at a temperature of about 400 0 to about 900 0 C for about 30 to about 150 minutes. Further, the actinide oxysulfite tetrahydrate can be partially dehydrated at reduced pressures (and in the presence of a suitable dehydrating agent such as phosphorus pentoxide). The partially dehydrated product may be readily converted to the dioxide form by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) at a temperature of about 500 0 to about 900 0 C for about 30 to about 150 minutes. 16 claims

  9. Nitrogen dioxide exposures inside ice skating rinks.

    Science.gov (United States)

    Brauer, M; Spengler, J D

    1994-01-01

    OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

  10. Sol-gel growth of vanadium dioxide

    International Nuclear Information System (INIS)

    Speck, K.R.

    1990-01-01

    This thesis examines the chemical reactivity of vanadium (IV) tetrakis(t-butoxide) as a precursor for the sol-gel synthesis of vanadium dioxide. Hydrolysis and condensation of the alkoxide was studied by FTIR spectroscopy. Chemical modification of the vanadium tetraalkoxide by alcohol interchange was studied using 51 V NMR and FTIR. Vanadium dioxide thin films and powders were made from vanadium tetrakis(t-butoxide) by standard sol-gel techniques. Post-deposition heating under nitrogen was necessary to transform amorphous gels into vanadium dioxide. Crystallization of films and powders was studied by FTIR, DSC, TGA, and XRD. Gel-derived vanadium dioxide films undergo a reversible semiconductor-to-metal phase transition near 68C, exhibiting characteristic resistive and spectral changes. The electrical resistance decreased by two to three orders of magnitude and the infrared transmission sharply dropped as the material was cycled through this thermally induced phase transition. The sol-gel method was also used to make doped vanadium dioxide films. Films were doped with tungsten and molybdenum ions to effectively lower the temperature at which the transition occurs

  11. Effects of sulfur dioxide on vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, G S

    1939-11-11

    A discussion is presented on the effects of sulfur dioxide on vegetation as observed at Trail, British Columbia. The investigation was carried out over a period of eight years, 1929 to 1937. The concentration of sulfur dioxide at the United States border was carefully determined throughout the crop season at a point 16 miles from the source of sulfur dioxide. Maximum and average concentrations in part per million are given. The sulfur content of vegetation was determined and was found to diminish as the distance from the smelter increased. It was determined that the sulfur content may rise to four times the normal amount without injurious effect. This is particularly so with prolonged low concentration. The effect on the soil was determined by measuring soluble sulfate, pH and exchangeable bases. The soil near the plant was affected, but this fell off rapidly with increase in distance so that eight miles from the smelter the soil was substantially normal. No effect on water supplies was found. An appreciable retardation in growth, as determined by annular rings, was noted for trees exposed to the sulfur dioxide. This effect was lost following installation of sulfur dioxide control at Trail. Conifers were found more susceptible during periods of active growth than when dormant. Also, transplanted conifers were more severly affected than native trees. Seedlings were less resistant that older trees.

  12. Carbon dioxide and climate: an astrophysical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kandel, R S

    1979-01-01

    In this survey the earth is viewed from the astrophysical perspective, i.e. using global mean values of environmental parameters. The role of carbon dioxide is described in the processes of energy transfer from the earth's surface to space, which determine global climate as measured by the mean surface temperature. Analogies and differences between the problems of the terrestrial atmosphere and those of the solar and stellar atmospheres are examined, both in the computation of model atmospheres and in remote sensing of atmospheric temperature and composition. Subsequently, the temporal astrophysical perspective, with a review of the evolution of CO/sub 2/ abundance and climate on astrophysical or geological time scales, on earth as an Venus (the runaway greenhouse) and on Mars is introduced. Variation of CO/sub 2/ may have been critical to the maintenance of an environment in which life could originate and evolve, and may itself have been affected by life. On human time scales, the recent and continuing increase in atmospheric CO/sub 2/ raises new problems, which are briefly surveyed. It is argued, that the differential greenhouse effect of increased CO/sub 2/ in the earth's atmosphere is essentially identifical to the blanketing effect of spectral lines on the temperature structure of stellar atmospheres. The methods used by astrophysicists in such studies are reviewed and compared with those used to evaluate the differential greenhouse effect of CO/sub 2/ in radiative-convective models of the earth's atmosphere. The latter methods remain relatively crude, but recent results by different authors are in reasonably good agreement; however, the astrophysical perspective, i.e. the use of one-dimensional global mean models, remains a gross simplification of the real complexity of the earth's climate system, which is also true in stellar atmospheres.

  13. Carbon dioxide thesaurus: a comprehensive list of terms in use in the CO2 field

    International Nuclear Information System (INIS)

    Redford, J.S.

    1981-10-01

    Standardized terms structured to allow consistent machine storage and retrieval of information pertaining to carbon dioxide and the environment are included in this thesaurus. Although terminology is based on the Energy Data Base Subject Thesaurus used by the Technical Information Center in indexing information of importance to the DOE mission, additional terms highly specific to the CO 2 literature are also included

  14. Photoluminescence and hydrogen gas-sensing properties of titanium dioxide nanostructures synthesized by hydrothermal treatments

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2012-03-01

    Full Text Available Titanium dioxide (TiO2) nanostructures were synthesized by microwave-assisted and conventionally heated hydrothermal treatment of TiO2 powder. The tubular structures were converted to a rodlike shape by sintering the samples at various temperatures...

  15. Polymorph-dependent titanium dioxide nanoparticle dissolution in acidic and alkali digestions

    Science.gov (United States)

    Multiple polymorphs (anatase, brookite and rutile) of titanium dioxide nanoparticles (TiO2-NPs) with variable structures were quantified in environmental matrices via microwave-based hydrofluoric (HF) and nitric (HNO3) mixed acid digestion and muffle furnace (MF)-based potassium ...

  16. Structuralism.

    Science.gov (United States)

    Piaget, Jean

    Provided is an overview of the analytical method known as structuralism. The first chapter discusses the three key components of the concept of a structure: the view of a system as a whole instead of so many parts; the study of the transformations in the system; and the fact that these transformations never lead beyond the system but always…

  17. Reaction of titanium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

    1987-01-01

    It has been ascertained that heating titanium and tantalum in carbon dioxide to temperatures of 500 or 800 0 C alters the composition of the gas phase, causing the advent of carbon monoxide and lowering the oxygen content. Investigation of the thermal stability of titanium polonides in a carbon dioxide medium has shown that titanium mono- and hemipolonides are decomposed at temperatures below 350 0 C. The temperature dependence of the vapor pressure of polonium produced in the decomposition of these polonides in a carbon dioxide medium have been determined by a radiotensimetric method. The enthalpy of the process, calculated from this relationship, is close to the enthalpy of vaporization of elementary polonium in vacuo

  18. Measurement of nitrogen dioxide in the air

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J T

    1967-01-01

    The Hersch electrolytic nitrogen dioxide generator has been used to provide accurately known weights of nitrogen dioxide and hence to evaluate a calibration factor for the colorimetric reagent described by Saltaman for the determination of this gas. A method of testing whether the electrolytic generator was giving a quantitative output of NO/sub 2/ is described. The work has confirmed Saltman's value of 0.72 for the calibration factor. An assertion that the calibration factor is dependent on the concentration of nitrogen dioxide sampled, is re-examined and dismissed, the observations being re-interpreted on a simple basis. A tentative suggestion is made as to why, in recent work by Stratmann and Buck, a calibration factor equal to unity has been found. 8 references, 4 figures, 1 table.

  19. Use of carbon dioxide as an intravascular contrast agent: A review of current literature

    OpenAIRE

    Ali, Fahad; Mangi, Muhammad Asif; Rehman, Hiba; Kaluski, Edo

    2017-01-01

    Use of X-ray contrast allows us to differentiate between two or more adjacent structures on radiographic studies. The X-ray contrast agent can be the one with increase X-ray absorption, like iodine and a barium X-ray contrast agent or the one with decrease X-ray absorption like air and carbon dioxide contrast agent. Each contrast agent possesses different risks and benefits in various ways. Carbon dioxide as an intravascular contrast agent can be used as an alternative intravascular contrast ...

  20. Evaluation of uranium dioxide thermal conductivity using molecular dynamics simulations

    International Nuclear Information System (INIS)

    Kim, Woongkee; Kaviany, Massoud; Shim, J. H.

    2014-01-01

    It can be extended to larger space, time scale and even real reactor situation with fission product as multi-scale formalism. Uranium dioxide is a fluorite structure with Fm3m space group. Since it is insulator, dominant heat carrier is phonon, rather than electrons. So, using equilibrium molecular dynamics (MD) simulation, we present the appropriate calculation parameters in MD simulation by calculating thermal conductivity and application of it to the thermal conductivity of polycrystal. In this work, we investigate thermal conductivity of uranium dioxide and optimize the parameters related to its process. In this process, called Green Kubo formula, there are two parameters i.e correlation length and sampling interval, which effect on ensemble integration in order to obtain thermal conductivity. Through several comparisons, long correlation length and short sampling interval give better results. Using this strategy, thermal conductivity of poly crystal is obtained and comparison with that of pure crystal is made. Thermal conductivity of poly crystal show lower value that that of pure crystal. In further study, we broaden the study to transport coefficient of radiation damaged structures using molecular dynamics. Although molecular dynamics is tools for treating microscopic scale, most macroscopic issues related to nuclear materials such as voids in fuel materials and weakened mechanical properties by radiation are based on microscopic basis. Thus, research on microscopic scale would be expanded in this field and many hidden mechanism in atomic scales will be revealed via both atomic scale simulations and experiments

  1. Determination of the stoichiometric ratio uranium dioxide samples

    International Nuclear Information System (INIS)

    Moura, Sergio Carvalho

    1999-01-01

    The determination of the O/U stoichiometric ratio in uranium dioxide is an important parameter in order to qualify nuclear fuels. The excess oxygen in the crystallographic structure can cause changes in the physico-chemical properties of this compound such as variation of the thermal conductivity alterations, fuel plasticity and others, affecting the efficiency of this material when it is utilized as nuclear fuel in the reactor core. The purpose of this work is to evaluate methods for the determination of uranium oxide samples from two different production processes, using gravimetric, voltammetric and X-ray diffraction techniques. After the evaluation of these techniques, the main aspect of this work is to define a reliable methodology in order to characterize the behavior of uranium oxide. The methodology used in this work consisted of two different steps: utilization of gravimetric and volumetric methods in order to determine the ratio in uranium dioxide samples; utilization of X-ray diffraction technique in order to determine the lattice parameters using patterns and application of the Rietveld method during refining of the structural data. As a result of the experimental part of this work it was found that the X-ray diffraction analysis performs better and detects the presence of more phases than gravimetric and voltammetric techniques, not sensitive enough in this detection. (author)

  2. INTERACTION OF CARBON DIOXIDE WITH CARBON ADSORBENTS BELOW 400 C

    Energy Technology Data Exchange (ETDEWEB)

    Deitz, V R; Carpenter, F G; Arnold, R G

    1963-06-15

    The adsorption of carbon dioxide on carbon adsorbents (FT carbon, coconut charcoal, acid-washed bone char) and adsorbents containing basic calcium phosphate (hydroxylapatite, bone char, ash of bone char) was studied. Special consideration was given to the pretreatment of the materials. The carbons equilibrated as rapidly as the temperature; the basic calcium phosphates showed a rapid initial adsorption followed by a very slow rate which continued for days. Linear adsorption isotherms were found on FT carbon and the isosteric heats varied slightiy with coverage. The isotherms for the remaining materials had varying curvature and were for the most part in the same sequence as the estimated surface areas. The isosteric heats of carbon dioxide correlated very well with the magnitude of surface hydroxyl groups, an estimate of which was made from the chemical composition. There appeared to be three increasing levels of interaction: (1) pure physical adsorption; (2) an adsorption complex having 'bicarbonate structure'; and (3) an adsorption complex having 'carbonate structure'. (auth)

  3. High-pressure phase transformations of fluorite-type dioxides

    International Nuclear Information System (INIS)

    Lin-Gun Liu

    1980-01-01

    Phase transformations in six fluorite-type dioxides ('TbO 2 ', PbO 2 , 'PrO 2 ', CeO 2 , UO 2 and ThO 2 in the order of increasing cation size, where the quotation marks indicate non-stoichiometric materials) have been investigated in the diamond-anvil press coupled with laser heating. Together with earlier work, the results show that the post-fluorite phase transformations of these dioxides fall into two groups. The smaller cation group (HfO 2 , ZrO 2 and 'TbO 2 ') transforms to a cotunnite or a distorted cotunnite-type structure at pressures in the vicinity of 100 kbar and at about 1000 0 C. The larger cation group (from PbO 2 to ThO 2 ) is believed to transform to a different type of orthorhombic modification at high pressures. It is plausible that this high-pressure phase may possess a Ni 2 Si-related structure, as was observed in ThO 2 and 'PrO 2 ' at pressures greater than 150 and 200 kbar, respectively. (orig./ME)

  4. Carbon dioxide problem: solution by technical countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Bach, W

    1978-02-15

    A rough assessment indicates that anthropogenic influences might raise the mean global surface temperature by 0.8 to 1.2 C in 2000 AD and by 2 to 4 C in 2050 AD. The rapidly increasing levels of atmospheric carbon dioxide are largely responsible for this warming trend. A variety of measures for the reduction of carbon dioxide emissions is presented. One promising approach is to work out a world-wide energy mix that can counteract a temperature increase. (In German)

  5. Environmental effects of increased atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Soon, W.; Baliunas, S.L.; Robinson, A.B.; Robinson, Z.W.

    1999-01-01

    A review of the literature concerning the environmental consequences of increased levels of atmospheric carbon dioxide leads to the conclusion that increases during the 20th century have produced no deleterious effects upon global climate or temperature. Increased carbon dioxide has, however, markedly increased plant growth rates as inferred from numerous laboratory and field experiments. There is no clear evidence, nor unique attribution, of the global effects of anthropogenic CO 2 on climate. Meaningful integrated assessments of the environmental impacts of anthropogenic CO 2 are not yet possible because model estimates of global and regional climate changes on interannual, decadal and centennial timescales remain highly uncertain.(author)

  6. Biological fixation of carbon dioxide. Seibutsu ni yoru nisanka tanso no kotei

    Energy Technology Data Exchange (ETDEWEB)

    Someya, J [Fermentaion Research Institute, Tsukuba (Japan)

    1991-10-20

    Bulks of photosynthetic product to reduce the carbon dioxide by the light energy are forests, represented by the tropical rain forests, on the land, and marine algae and coral reefs in the ocean. For the purpose of effectively utilizing the fixation power of carbon dioxide through the photosynthesis by higher plants and algae, it is necessary to make many further researches, starting with a conditional selection of species, excellent in both absorption and fixation of carbon dioxide. The Japan Technology Transfer Association has recently issued a design to build a large scale closed type farm in the vicinity of factory, exhausting the carbon dioxide, and supply it to structure a system of producing vegetable and other food. What largely contributes to the calcification in the ocean is the coral reefs, where coral is symbiotic with brown algae., called dinoflagellatae. Those algae are judged to accelerate the formation of calcium carbonate by the photosynthesis. To estimate the absorption power of oceanic carbon dioxide, it is important to quantitatively know the calcification by the coral. 4 figs., 1 tab.

  7. Thermodynamic promotion of carbon dioxide-clathrate hydrate formation by tetrahydrofuran, cyclopentane and their mixtures

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2013-01-01

    Gas clathrate hydrate dissociation pressures are reported for mixtures of carbon dioxide, water and thermodynamic promoters forming structure II hydrates.Hydrate (H)-aqueous liquid (Lw)-vapour (V) equilibrium pressures for the ternary system composed of water, tetrahydrofuran (THF), and carbon....... It is shown that upon adding THF to the pure aqueous phase to form a 4mass percent solution, the equilibrium pressure of the formed hydrates may be lowered compared to the ternary system of water, cyclopentane and carbon dioxide. © 2013 Elsevier Ltd....... dioxide (CO2), with 5.0mole percent THF in the initial aqueous phase, are presented in the temperature range from 283.3K to 285.2K. At 283.3K, the three-phase equilibrium pressure is determined to be 0.61MPa (absolute pressure).Four-phase hydrate (H)-aqueous liquid (Lw)-organic liquid (La)-vapour (V...

  8. Effect of pressure on f-electron delocalization and oxidation in actinide dioxides

    Energy Technology Data Exchange (ETDEWEB)

    Petit, L., E-mail: leon.petit@stfc.ac.uk [Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Szotek, Z.; Temmerman, W.M. [Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Stocks, G.M. [Materials Science and Technology Division and Center for Defect Physics, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Svane, A. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

    2014-08-01

    Using first principles calculations, we have investigated f-electron delocalization and oxidation in the actinide dioxides under pressure. Whilst UO{sub 2} is found on the verge of an insulator to metal transition at the equilibrium volume, increasingly larger pressures are required to delocalize f-electrons in NpO{sub 2}, PuO{sub 2}, and AmO{sub 2}, respectively 49, 112, and 191 GPa. Compared to this broad range of pressures, the experimentally observed structural transitions, in all four dioxides, occur between 30 and 40 GPa, which leads us to conclude that the associated volume collapse is not due to f-electron delocalization. In contrast, oxidation of the dioxides is found to be linked to the degree of f-electron localization, but it emerges that for naturally occurring pressures (<10 GPa), higher oxides only exist for UO{sub 2}.

  9. A supercritical carbon dioxide plasma process for preparing tungsten oxide nanowires

    International Nuclear Information System (INIS)

    Kawashima, Ayato; Nomura, Shinfuku; Toyota, Hiromichi; Takemori, Toshihiko; Mukasa, Shinobu; Maehara, Tsunehiro

    2007-01-01

    A supercritical carbon dioxide (CO 2 ) plasma process for fabricating one-dimensional tungsten oxide nanowires coated with amorphous carbon is presented. High-frequency plasma was generated in supercritical carbon dioxide at 20 MPa by using tungsten electrodes mounted in a supercritical cell, and subsequently an organic solvent was introduced with supercritical carbon dioxide into the plasma. Electron microscopy and Raman spectroscopy investigations of the deposited materials showed the production of tungsten oxide nanowires with or without an outer layer. The nanowires with an outer layer exhibited a coaxial structure with an outer concentric layer of amorphous carbon and an inner layer of tungsten oxide with a thickness and diameter of 20-30 and 10-20 nm, respectively

  10. Determination of sulfur dioxide by a radiorelease method

    Energy Technology Data Exchange (ETDEWEB)

    Sriman Narayanan, S.; Rao, V.R.S. (Indian Inst. of Tech., Madras. Dept. of Chemistry)

    1983-04-13

    A radiorelease technique for the determination of sulfur dioxide using radiochlor /sup 36/Cl-amine-T is described. Methods for the elimination of interference from coexisting gases are also reported. 1-40 ppm sulfur dioxide can be determined.

  11. Determination of sulfur dioxide by a radiorelease method

    International Nuclear Information System (INIS)

    Sriman Narayanan, S.; Rao, V.R.S.

    1983-01-01

    A radiorelease technique for the determination of sulfur dioxide using radiochlor 36 Cl-amine-T is described. Methods for the elimination of interference from coexisting gases are also reported. 1-40 ppm sulfur dioxide can be determined. (author)

  12. Catalyst retention in continuous flow with supercritical carbon dioxide

    NARCIS (Netherlands)

    Stouten, S.C.; Noel, T.; Wang, Q.; Hessel, V.

    2014-01-01

    This review discusses the retention of organometallic catalysts in continuous flow processes utilizing supercritical carbon dioxide. Due to its innovative properties, supercritical carbon dioxide offers interesting possibilities for process intensification. As a result of safety and cost

  13. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. [Reserved] 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...: Nitrogen dioxide. [Reserved] ...

  14. Effect of minor addition of titanium- and molybdenum dioxides on thermodynamic properties of vanadium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vasil' eva, I A; Sulejmenova, G S

    1984-07-01

    The effect of minor additions (0.5 and 1%) of TiO2 and MoO2 on the partial thermodynamic functions of oxygen in vanadium dioxide was studied by the method of electromotive force with solid electrolyte on the base of stabilized ZrO2 possessing the oxygen conductivity. Investigations were conducted at 1050-1360 K for single-phase samples of monoclinic crystal structure. The addition MoO2 to VO2 is shown to reduce the equilibrium oxygen pressure above the Vsub(1-x) Msub(x)Osub(1.998) (M=Mo, Ti) thiosulfate ion in aqueous solution. Three thiosulfates of monovalent indium were isolated in solid state: In2S2O3x2H2O, In2S2O3xInOHx2H2O and In2S2O3x2InNO3x2H2O. Infrared spectra were investigated and thermal decomposition of prepared compounds was studied.

  15. Effect of sulfur dioxide on proteins of the vegetable organism

    Energy Technology Data Exchange (ETDEWEB)

    Reckendorfer, P; Beran, F

    1931-01-01

    Experiments were performed to determine the effects of sulfur dioxide on red clover in a controlled environment. An increase in the concentration of sulfur dioxide caused a significant decrease in the digestible protein. However, after the sulfur dioxide was discontinued, there was a decrease in the indigestible protein. The leaves showed an increase in spotting with an increase in sulfur dioxide concentration. Chemical analysis of the soil revealed a higher sulfur content in these experiments.

  16. Array of titanium dioxide nanostructures for solar energy utilization

    Science.gov (United States)

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

  17. Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during ...

    African Journals Online (AJOL)

    Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during laparoscopic surgery: changes in pH, arterial partial Pressure of Carbon Dioxide (PaCo 2 ) and End Tidal Carbon Dioxide (EtCO 2 ) ... Respiratory adjustments were done for EtCO2 levels above 60mmHg or SPO2 below 92% or adverse haemodynamic changes.

  18. 27 CFR 24.319 - Carbon dioxide record.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Carbon dioxide record. 24..., DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.319 Carbon dioxide record. A proprietor who uses carbon dioxide in still wine shall maintain a record of the laboratory tests conducted to...

  19. 40 CFR 180.444 - Sulfur dioxide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... § 180.444 Sulfur dioxide; tolerances for residues. A tolerance is established as follows for sulfite residues of the fungicide sulfur dioxide (determined as (SO2)) in or on the following raw agricultural... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Sulfur dioxide; tolerances for...

  20. 27 CFR 26.222 - Still wines containing carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... carbon dioxide. 26.222 Section 26.222 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... ISLANDS Formulas for Products From the Virgin Islands § 26.222 Still wines containing carbon dioxide. (a) General. Still wines may contain not more than 0.392 gram of carbon dioxide per 100 milliliters of wine...

  1. 27 CFR 26.52 - Still wines containing carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... carbon dioxide. 26.52 Section 26.52 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... ISLANDS Formulas for Products From Puerto Rico § 26.52 Still wines containing carbon dioxide. (a) General. Still wines may contain not more than 0.392 gram of carbon dioxide per 100 milliliters of wine; except...

  2. Microwave Effect for Glycosylation Promoted by Solid Super Acid in Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Takahiko Maeda

    2009-12-01

    Full Text Available The effects of microwave irradiation (2.45 GHz, 200 W on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule.

  3. 21 CFR 172.480 - Silicon dioxide.

    Science.gov (United States)

    2010-04-01

    ... alcohol in tableted foods for special dietary use, in an amount not greater than that required to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silicon dioxide. 172.480 Section 172.480 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  4. Yellow cake to ceramic uranium dioxide

    International Nuclear Information System (INIS)

    Zawidzki, T.W.; Itzkovitch, I.J.

    1983-01-01

    This overview article first reviews the processes for converting uranium ore concentrates to ceramic uranium dioxide at the Port Hope Refinery of Eldorado Resources Limited. In addition, some of the problems, solutions, thoughts and research direction with respect to the production and properties of ceramic UO 2 are described

  5. Carbon dioxide capture and air quality

    NARCIS (Netherlands)

    Horssen, A. van; Ramirez, C.A.; Harmelen, T. van; Koornneef, J.

    2011-01-01

    Carbon dioxide (CO2) is one of the most important greenhouse gases (GHG). The most dominant source of anthropogenic CO2 contributing to the rise in atmospheric concentration since the industrial revolution is the combustion of fossil fuels. These emissions are expected to result in global climate

  6. Electrocatalytic carbon dioxide reduction - a mechanistic study

    NARCIS (Netherlands)

    Schouten, Klaas Jan Schouten

    2013-01-01

    This thesis presents new insights into the reduction of carbon dioxide to methane and ethylene on copper electrodes. This electrochemical process has great potential for the storage of surplus renewable electrical energy in the form of hydrocarbons. The research described in this thesis focuses on

  7. Carbon dioxide enhances fragility of ice crystals

    International Nuclear Information System (INIS)

    Qin Zhao; Buehler, Markus J

    2012-01-01

    Ice caps and glaciers cover 7% of the Earth, greater than the land area of Europe and North America combined, and play an important role in global climate. The small-scale failure mechanisms of ice fracture, however, remain largely elusive. In particular, little understanding exists about how the presence and concentration of carbon dioxide molecules, a significant component in the atmosphere, affects the propensity of ice to fracture. Here we use atomic simulations with the first-principles based ReaxFF force field capable of describing the details of chemical reactions at the tip of a crack, applied to investigate the effects of the presence of carbon dioxide molecules on ice fracture. Our result shows that increasing concentrations of carbon dioxide molecules significantly decrease the fracture toughness of the ice crystal, making it more fragile. Using enhanced molecular sampling with metadynamics we reconstruct the free energy landscape in varied chemical microenvironments and find that carbon dioxide molecules affect the bonds between water molecules at the crack tip and decrease their strength by altering the dissociation energy of hydrogen bonds. In the context of glacier dynamics our findings may provide a novel viewpoint that could aid in understanding the breakdown and melting of glaciers, suggesting that the chemical composition of the atmosphere can be critical to mediate the large-scale motion of large volumes of ice.

  8. Diiodination of Alkynes in supercritical Carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 谢叶香; 尹笃林; 江焕峰

    2003-01-01

    A general,green and efficient method for the synthesis of transdiiodoalkenes in CO2(sc) has been developed.Trans-diiodoalkenes were obtained stereospecifically in quantitative yields via diiodination of both electron-rich and electron-deficient alkynes in the presence of KI,Ce(SO4)2 and water in supercritical carbon dioxide [CO2(sc)]at 40℃.

  9. Tourism Transport, Technology, and Carbon Dioxide Emissions

    NARCIS (Netherlands)

    Peeters, P.M.

    2010-01-01

    Technological development from horse-drawn carriages to the new Airbus A380 has led to a remarkable increase in both the capacity and speed of tourist travel. This development has an endogenous systemic cause and will continue to increase carbon dioxide emissions/energy consumption if left

  10. Improved ionic model of liquid uranium dioxide

    NARCIS (Netherlands)

    Gryaznov, [No Value; Iosilevski, [No Value; Yakub, E; Fortov, [No Value; Hyland, GJ; Ronchi, C

    The paper presents a model for liquid uranium dioxide, obtained by improving a simplified ionic model, previously adopted to describe the equation of state of this substance [1]. A "chemical picture" is used for liquid UO2 of stoichiometric and non-stoichiometric composition. Several ionic species

  11. Carbon dioxide sensing with sulfonated polyaniline

    NARCIS (Netherlands)

    Doan, D.C.T.; Ramaneti, R.; Baggerman, J.; Bent, van der J.; Marcelis, A.T.M.; Tong, H.D.; Rijn, van C.J.M.

    2012-01-01

    The use of polyaniline and especially sulfonated polyaniline (SPAN) is explored for sensing carbon dioxide (CO2) at room temperature. Frequency-dependent AC measurements were carried out to detect changes in impedance of the polymer, drop casted on interdigitated electrodes, when exposed to CO2 gas.

  12. Conductive polymers for carbon dioxide sensing

    NARCIS (Netherlands)

    Doan, T.C.D.

    2012-01-01

    Augmented levels of carbon dioxide (CO2) in greenhouses stimulate plant growth through photosynthesis. Wireless sensor networks monitoring CO2 levels in greenhouses covering large areas require preferably low power sensors to minimize energy consumption. Therefore, the main

  13. Transport properties of supercritical carbon dioxide

    NARCIS (Netherlands)

    Lavanchy, F.; Fourcade, E.; de Koeijer, E.A.; Wijers, J.G.; Meyer, T.; Keurentjes, J.T.F.; Kemmere, M.F.; Meyer, T.

    2005-01-01

    Recently, supercritical fluids have emerged as more sustainable alternatives for the organic solvents often used in polymer processes. This is the first book emphasizing the potential of supercritical carbon dioxide for polymer processes from an engineering point of view. It develops a

  14. Blended polymer materials extractable with supercritical carbon dioxide

    Science.gov (United States)

    Cai, Mei

    Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a much broader range of physical and chemical transformations. However the available data show that a lot of commercially valuable substances are not soluble in supercritical carbon dioxide due to their polar structures. This fact really limits the application of SCF extraction technology to much broader industrial applications. Therefore, the study of a polymer's solubility in a given supercritical fluid and its thermodynamic behavior becomes one of the most important research topics. The major objective of this dissertation is to develop a convenient and economic way to enhance the polymer's solubility in supercritical carbon dioxide. Further objective is to innovate a new process of making metal casting parts with blended polymer materials developed in this study. The key technique developed in this study to change a polymer's solubility in SCF CO2 is to thermally blend a commercially available and CO2 non-soluble polymer material with a low molecular weight CO2 soluble organic chemical that acts as a co-solute. The mixture yields a plastic material that can be completely solubilized in SCF CO2 over a range of temperatures and pressures. It also exhibits a variety of physical properties (strength, hardness, viscosity, etc.) depending on variations in the mixture ratio. The three organic chemicals investigated as CO2 soluble materials are diphenyl carbonate, naphthalene, and benzophenone. Two commercial polymers, polyethylene glycol and polystyrene, have been investigated as CO2 non-soluble materials. The chemical

  15. Experimental investigations of driven Alfven wave resonances in a tokamak plasma using carbon dioxide laser interferometry

    International Nuclear Information System (INIS)

    Evans, T.E.

    1984-09-01

    The first direct observation of the internal structure of driven global Alfven eigenmodes in a tokamak plasma is presented. A carbon dioxide laser scattering/interferometer has been designed, built, and installed on the PRETEXT tokamak. By using this diagnostic system in the interferometer configuration, we have for the first time, thoroughly investigated the resonance conditions required for, and the spatial wave field structure of, driven plasma eigenmodes at frequencies below the ion cyclotron frequency in a confined, high temperature, tokamak plasma

  16. Effects of rapid thermal annealing on structural, chemical, and electrical characteristics of atomic-layer deposited lanthanum doped zirconium dioxide thin film on 4H-SiC substrate

    International Nuclear Information System (INIS)

    Lim, Way Foong; Quah, Hock Jin; Lu, Qifeng; Mu, Yifei; Ismail, Wan Azli Wan; Rahim, Bazura Abdul; Esa, Siti Rahmah; Kee, Yeh Yee; Zhao, Ce Zhou

    2016-01-01

    Graphical abstract: - Highlights: • Studies of RTA temperatures on La doped ZrO2 atomic layer deposited on 4HSiC. • Oxygen vacancies improved insulating and catalytic properties of La doped ZrO2. • 700 °C annealed sample showed the highest EB, k value, and sensitivity on O2. • La doped ZrO2 was proposed as a potential metal reactive oxide on 4H-SiC. - Abstract: Effects of rapid thermal annealing at different temperatures (700–900 °C) on structural, chemical, and electrical characteristics of lanthanum (La) doped zirconium oxide (ZrO_2) atomic layer deposited on 4H-SiC substrates have been investigated. Chemical composition depth profiling analysis using X-ray photoelectron spectroscopy (XPS) and cross-sectional studies using high resolution transmission electron microscopy equipped with energy dispersive X-ray spectroscopy line scan analysis were insufficient to justify the presence of La in the investigated samples. The minute amount of La present in the bulk oxide was confirmed by chemical depth profiles of time-of-flight secondary ion mass spectrometry. The presence of La in the ZrO_2 lattice led to the formation of oxygen vacancies, which was revealed through binding energy shift for XPS O 1s core level spectra of Zr−O. The highest amount of oxygen vacancies in the sample annealed at 700 °C has yielded the acquisition of the highest electric breakdown field (∼ 6.3 MV/cm) and dielectric constant value (k = 23) as well as the highest current–time (I–t) sensor response towards oxygen gas. The attainment of both the insulating and catalytic properties in the La doped ZrO_2 signified the potential of the doped ZrO_2 as a metal reactive oxide on 4H-SiC substrate.

  17. Convergence in carbon dioxide emissions among industrialised countries revisited

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Avila, Diego [Pablo de Olavide University, Department of Economics, Carretera de Utrera, Km. 1, 41089, Seville (Spain)

    2008-09-15

    This paper examines the existence of stochastic and deterministic convergence of carbon dioxide (CO{sub 2}) emissions in 23 countries over the period 1960-2002. For that purpose, we conduct unit root testing by employing the recently developed panel stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre, J-L, del Barrio-Castro, T., Lopez-Bazo, E., 2005. Breaking the panels: An application to the GDP per capita. Econometrics Journal 8, 159-175] which assumes a highly flexible trend function by incorporating an unknown number of structural breaks. We accommodate general forms of cross-sectional dependence as well as control for finite-sample bias through bootstrap methods. Overall, our analysis provides strong evidence supporting both stochastic and deterministic convergence in CO{sub 2} emissions, thus confirming Strazicich and List [Strazicich, M.C., List, J.A., 2003. Are CO{sub 2} emission levels converging among industrial countries? Environmental and Resource Economics 24, 263-271] and Westerlund and Basher [Westerlund, J., Basher, S.A., 2007. Testing for convergence in carbon dioxide emissions using a century of panel data. Environmental and Resource Economics, forthcoming] findings of convergence. (author)

  18. Convergence in carbon dioxide emissions among industrialised countries revisited

    International Nuclear Information System (INIS)

    Romero-Avila, Diego

    2008-01-01

    This paper examines the existence of stochastic and deterministic convergence of carbon dioxide (CO 2 ) emissions in 23 countries over the period 1960-2002. For that purpose, we conduct unit root testing by employing the recently developed panel stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre, J-L, del Barrio-Castro, T., Lopez-Bazo, E., 2005. Breaking the panels: An application to the GDP per capita. Econometrics Journal 8, 159-175] which assumes a highly flexible trend function by incorporating an unknown number of structural breaks. We accommodate general forms of cross-sectional dependence as well as control for finite-sample bias through bootstrap methods. Overall, our analysis provides strong evidence supporting both stochastic and deterministic convergence in CO 2 emissions, thus confirming Strazicich and List [Strazicich, M.C., List, J.A., 2003. Are CO 2 emission levels converging among industrial countries? Environmental and Resource Economics 24, 263-271] and Westerlund and Basher [Westerlund, J., Basher, S.A., 2007. Testing for convergence in carbon dioxide emissions using a century of panel data. Environmental and Resource Economics, forthcoming] findings of convergence

  19. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Navalon, Sergio; Alvaro, Mercedes; Garcia, Hermenegildo

    2009-01-01

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO 2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO 2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO 2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO 2 with ubiquitous amino acids present in natural waters.

  20. Titanium dioxide thin films by atomic layer deposition: a review

    Science.gov (United States)

    Niemelä, Janne-Petteri; Marin, Giovanni; Karppinen, Maarit

    2017-09-01

    Within its rich phase diagram titanium dioxide is a truly multifunctional material with a property palette that has been shown to span from dielectric to transparent-conducting characteristics, in addition to the well-known catalytic properties. At the same time down-scaling of microelectronic devices has led to an explosive growth in research on atomic layer deposition (ALD) of a wide variety of frontier thin-film materials, among which TiO2 is one of the most popular ones. In this topical review we summarize the advances in research of ALD of titanium dioxide starting from the chemistries of the over 50 different deposition routes developed for TiO2 and the resultant structural characteristics of the films. We then continue with the doped ALD-TiO2 thin films from the perspective of dielectric, transparent-conductor and photocatalytic applications. Moreover, in order to cover the latest trends in the research field, both the variously constructed TiO2 nanostructures enabled by ALD and the Ti-based hybrid inorganic-organic films grown by the emerging ALD/MLD (combined atomic/molecular layer deposition) technique are discussed.

  1. Titanium Dioxide Nanoparticles: a Risk for Human Health?

    Science.gov (United States)

    Grande, Fedora; Tucci, Paola

    2016-01-01

    Titanium dioxide (TiO2) is a natural oxide of the element titanium with low toxicity, and negligible biological effects. The classification as bio-inert material has given the possibility to normal-sized (>100 nm) titanium dioxide particles (TiO2-NPs) to be extensively used in food products and as ingredients in a wide range of pharmaceutical products and cosmetics, such as sunscreens and toothpastes. Therefore, human exposure may occur through ingestion and dermal penetration, or through inhalation route, during both the manufacturing process and use. In spite of the extensively use of TiO2-NPs, the biological effects and the cellular response mechanisms are still not completely elucidated and thus a deep understanding of the toxicological profile of this compound is required. The main mechanism underlining the toxicity potentially triggered by TiO2-NPs seems to involve the reactive oxygen species (ROS) production, resulting in oxidative stress, inflammation, genotoxicity, metabolic change and potentially carcinogenesis. The extent and type of cell damage strongly depend on chemical and physical characteristics of TiO2-NPs, including size, crystal structure and photo-activation. In this mini-review, we would like to discuss the latest findings on the adverse effects and on potential human health risks induced by TiO2-NPs exposure.

  2. Monitoring carbon dioxide in mechanically ventilated patients during hyperbaric treatment

    DEFF Research Database (Denmark)

    Bjerregård, Asger; Jansen, Erik

    2012-01-01

    Measurement of the arterial carbon dioxide (P(a)CO(2)) is an established part of the monitoring of mechanically ventilated patients. Other ways to get information about carbon dioxide in the patient are measurement of end-tidal carbon dioxide (P(ET)CO(2)) and transcutaneous carbon dioxide (PTCCO2......). Carbon dioxide in the blood and cerebral tissue has great influence on vasoactivity and thereby blood volume of the brain. We have found no studies on the correlation between P(ET)CO(2) or P(TC)CO(2), and P(a)CO(2) during hyperbaric oxygen therapy (HBOT)....

  3. Energy efficient solvent regeneration process for carbon dioxide capture

    Science.gov (United States)

    Zhou, Shaojun; Meyer, Howard S.; Li, Shiguang

    2018-02-27

    A process for removing carbon dioxide from a carbon dioxide-loaded solvent uses two stages of flash apparatus. Carbon dioxide is flashed from the solvent at a higher temperature and pressure in the first stage, and a lower temperature and pressure in the second stage, and is fed to a multi-stage compression train for high pressure liquefaction. Because some of the carbon dioxide fed to the compression train is already under pressure, less energy is required to further compress the carbon dioxide to a liquid state, compared to conventional processes.

  4. Enhancement of magneto-conductance in n-Si/n-PS/NPB structures at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Radaoui, M., E-mail: Raddaouimoufid@gmail.com [Laboratoire Matériaux Avancés et Phénomènes Quantiques, Faculté des Sciences de Tunis, Université El Manar, 2092 Campus Universitaire, Tunis (Tunisia); Ben Fredj, A. [Laboratoire Matériaux Avancés et Phénomènes Quantiques, Faculté des Sciences de Tunis, Université El Manar, 2092 Campus Universitaire, Tunis (Tunisia); Romdhane, S. [Laboratoire Matériaux Avancés et Phénomènes Quantiques, Faculté des Sciences de Tunis, Université El Manar, 2092 Campus Universitaire, Tunis (Tunisia); Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Bizerte (Tunisia); Bouaïcha, M. [Laboratoire de Photovoltaïque, Centre de Recherches et des Technologies de l’Energie, BP 95, Hammam-Lif 2050 (Tunisia); Bouchriha, H. [Laboratoire Matériaux Avancés et Phénomènes Quantiques, Faculté des Sciences de Tunis, Université El Manar, 2092 Campus Universitaire, Tunis (Tunisia)

    2013-12-01

    Highlights: • Current–voltage (I–V) characteristic of the Al/NPB/n-porous-silicon/silicon/Al. • Magnetic effect on I(V). • Use of two porosities P{sub 1} = 46% and P{sub 2} = 55% with fixed thicknesses of the NPB. • Ideality factors, barrier heights, series resistance are extracted. • Observation of a positive magneto-conductance (MC). • MC attained values of 4.7% for a magnetic field around 0.8 T. -- Abstract: Hybrid organic–inorganic semiconductor heterojunction with a sandwich structure have been prepared and studied. The inorganic semiconductor is n-type Porous Silicon (n-PS) elaborated on n-type crystalline silicon, the used conjugated polymer is the N,N′-diphenyl-N,N′-bis(1-naphthyl-pheny1)-(1,1′-biphenyl)-4,4′-diamine (NPB). Current–voltage (I–V) at transverse static magnetic field effect was used to study the electrical properties of the devices at room temperature. The electrical parameters such as the ideality factor ‘n’, the barrier height and the series resistance are determined from the I–V curve. We report the observed magneto-conductance (MC) in a weak magnetic field. The observed positive MC was enhanced when we partially filled pores with the NPB. This effect reaches up to 4.7% at a magnetic field of 0.8 T.

  5. The Crystal structure of InAs nanorods grown onto Si[111] substrate

    Energy Technology Data Exchange (ETDEWEB)

    Davydok, Anton; Biermanns, Andreas; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Walter-Flex-Str. 3,57072, Siegen (Germany); Breuer, Steffen; Dimakis, Manos; Geelhaar, Lutz [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2011-07-01

    Nanowires are of particular interest due to the ability to synthesize heterostructures in the nanometer range. It was found that nearly any AIIIBV semiconductor material can be grown as NWs onto another AIIIBV or group IV [111] substrate independent from lattice mismatch. We presented an X-ray characterization of InAs NRs on Si [111] grown by assist free MBE method. Lattice mismatch of this materials is 11%. For study of strain realizing we concentrated our research on initial stages of growth process investigating samples set with different growth time. Using synchrotron radiation we have performed experiments in symmetrical and asymmetrical out-of plane scattering geometry and grazing-incidence diffraction. Combining the results we were able to characterize the transition between silicon silicon substrate and InAs NWs. We find in-plane lattice mismatch of -0.18% close to the interface compared to InAs bulk material. With help of micro-focus setup we are able measure structural parameters of single NWs to determine the strain accomodation as function of NW size. In particular using asymmetric wurzite-sensitive reflections under coherent beam illumination we could quantify the number of stacking faults. In the talk we present details of the analysis and first simulation results.

  6. Research Progress in Carbon Dioxide Storage and Enhanced Oil Recovery

    Science.gov (United States)

    Wang, Keliang; Wang, Gang; Lu, Chunjing

    2018-02-01

    With the rapid development of global economy, human beings have become highly dependent upon fossil fuel such as coal and petroleum. Much fossil fuel is consumed in industrial production and human life. As a result, carbon dioxide emissions have been increasing, and the greenhouse effects thereby generated are posing serious threats to environment of the earth. These years, increasing average global temperature, frequent extreme weather events and climatic changes cause material disasters to the world. After scientists’ long-term research, ample evidences have proven that emissions of greenhouse gas like carbon dioxide have brought about tremendous changes to global climate. To really reduce carbon dioxide emissions, governments of different countries and international organizations have invested much money and human resources in performing research related to carbon dioxide emissions. Manual underground carbon dioxide storage and carbon dioxide-enhanced oil recovery are schemes with great potential and prospect for reducing carbon dioxide emissions. Compared with other schemes for reducing carbon dioxide emissions, aforementioned two schemes exhibit high storage capacity and yield considerable economic benefits, so they have become research focuses for reducing carbon dioxide emissions. This paper introduces the research progress in underground carbon dioxide storage and enhanced oil recovery, pointing out the significance and necessity of carbon dioxide-driven enhanced oil recovery.

  7. Uranium Dioxide Powder Flow ability Improvement Using Sol-Gel

    International Nuclear Information System (INIS)

    Juanda, D.; Sambodo Daru, G.

    1998-01-01

    The improvement of flow ability characteristics of uranium dioxide powder has been done using sol-gel process. To anticipate a pellet mass production with uniform pellet dimension, the uranium dioxide powder must be have a spherical form. Uranium dioxide spherical powder has been diluted in acid transformed into sol colloidal solution. To obtain uranium dioxide spherical form, the uranium sol-colloidal solution has been dropped in a hot paraffin ( at the temperature of 90 0 C) to form gelatinous colloid and then dried at 800 0 C, and sintered at the temperature of 1700 0 C. The flow ability of spherical uranium dioxide powder has been examined by using Flowmeter Hall (ASTM. B. 213-46T). The measurement result reveals that the spherical uranium dioxide powder has a flow ability twice than that of unprocessed uranium dioxide powder

  8. Carbon dioxide conversion over carbon-based nanocatalysts.

    Science.gov (United States)

    Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2013-07-01

    The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.

  9. Branch growth and gas exchange in 13-year old loblobby pine (Pinus taeda) trees in response to elevated carbon dioxide concentration and fertilization

    International Nuclear Information System (INIS)

    Maier, C. A.; Johnsen, K. H.; Butnor, J.; Kress, L. W.; Anderson, P. H.

    2002-01-01

    The combined effects of nutrient availability and carbon dioxide on growth and physiology in mature loblobby pine trees was investigated. Whole-tree open top chambers were used to expose 13-year old loblobby pine trees, growing in soil with high or low nutrient availability to elevated carbon dioxide to examine how carbon dioxide, foliar nutrition and crown position affect branch growth, phenology and physiology. Results showed that fertilization and elevated carbon dioxide increased branch leaf area, and the combined effects were additive. However, fertilization and elevated carbon dioxide differentially altered needle lengths, number of fascicles and flush length in such a way that flush density increased with improved nutrition but decreased with exposure to elevated carbon dioxide. Based on these results, it was concluded that changes in nitrogen availability and atmospheric carbon dioxide may alter canopy structure, facilitating greater foliage retention and deeper crowns in loblobby pine forests. Net photosynthesis and photosynthetic efficiency was increased in the presence of elevated carbon dioxide concentration and lowered the light compensation point, whereas fertilization had no appreciable effect on foliage gas exchange. 71 refs., 7 tabs., 7 figs

  10. Photoactivity of Titanium Dioxide Foams

    Directory of Open Access Journals (Sweden)

    Maryam Jami

    2018-01-01

    Full Text Available TiO2 foams have been prepared by a simple mechanical stirring method. Short-chain amphiphilic molecules have been used to stabilize colloidal suspensions of TiO2 nanoparticles. TiO2 foams were characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, UV-vis absorption spectroscopy, and scanning electron microscopy (SEM. The photoassisted oxidation of NO in the gas phase according to ISO 22197-1 has been used to compare the photoactivity of the newly prepared TiO2 foams to that of the original powders. The results showed that the photoactivity is increased up to about 135%. Foam structures seem to be a good means of improving the photoactivity of semiconductor materials and can readily be used for applications such as air purification devices.

  11. Structures for capturing CO.sub.2, methods of making the structures, and methods of capturing CO.sub.2

    Science.gov (United States)

    Jones, Christopher W; Hicks, Jason C; Fauth, Daniel J; McMahan, Gray

    2012-10-30

    Briefly described, embodiments of this disclosure, among others, include carbon dioxide (CO.sub.2) sorption structures, methods of making CO.sub.2 sorption structures, and methods of using CO.sub.2 sorption structures.

  12. Method and aparatus for flue gas cleaning by separation and liquefaction of sulfur dioxide and carbon dioxide

    International Nuclear Information System (INIS)

    Abdelmalek, F.T.

    1992-01-01

    This patent describes a method for recovering sulfur dioxide, carbon dioxide, and cleaning flue gases emitted from power plants. It comprises: electronically treating the flue gases to neutralize its electrostatic charges and to enhance the coagulation of its molecules and particles; exchanging sensible and latent heat of the neutralized flue gases to lower its temperature down to a temperature approaching the ambient temperature while recovering its separating the flue gas in a first stage; cooling the separated enriched carbon dioxide gas fraction, after each separation stage, while removing its vapor condensate, then compressing the enriched carbon dioxide gas fraction and simultaneously cooling the compressed gas to liquefy the sulfur dioxide gas then; allowing the sulfur dioxide gas to condense, and continuously removing the liquefied sulfur dioxide; compressing he desulfurized enriched carbon dioxide fraction to further increase its pressure, and simultaneously cooling he compressed gas to liquefy the carbon dioxide gas, then; allowing the carbon dioxide gas to condense and continuously removing the liquefied carbon dioxide; allowing the light components of the flue gas to be released in a cooling tower discharge plume

  13. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  14. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2011-02-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  15. Thermal properties of nonstoichiometry uranium dioxide

    Science.gov (United States)

    Kavazauri, R.; Pokrovskiy, S. A.; Baranov, V. G.; Tenishev, A. V.

    2016-04-01

    In this paper, was developed a method of oxidation pure uranium dioxide to a predetermined deviation from the stoichiometry. Oxidation was carried out using the thermogravimetric method on NETZSCH STA 409 CD with a solid electrolyte galvanic cell for controlling the oxygen potential of the environment. 4 samples uranium oxide were obtained with a different ratio of oxygen-to-metal: O / U = 2.002, O / U = 2.005, O / U = 2.015, O / U = 2.033. For the obtained samples were determined basic thermal characteristics of the heat capacity, thermal diffusivity, thermal conductivity. The error of heat capacity determination is equal to 5%. Thermal diffusivity and thermal conductivity of the samples decreased with increasing deviation from stoichiometry. For the sample with O / M = 2.033, difference of both values with those of stoichiometric uranium dioxide is close to 50%.

  16. Measurement of nitrogen dioxide in the air

    Energy Technology Data Exchange (ETDEWEB)

    Monteriolo, S C; Bertolaccini, M A

    1973-01-01

    A comparative study of automatic analytical methods for the monitoring of nitric oxide and nitrogen dioxide in the air indicates the need for a correct chemical conversion of the nonmeasurable species into the measurable species to obtain dependable results. The automatic colorimetric and chemiluminescent methods were compared to the manual colorimeter, and the electrochemical method was compared to chemiluminescence. Average, minimum, and maximum values are given for each comparison. All three methods are equally valid, in response linearity, sensitivity, and concentration limit, for the determination of nitric oxide, the measurable species. The determination of nitrogen dioxide, however, is strictly dependent on the efficiency of the conversion of the non-measurable species into the measurable form.

  17. Recycling technology of emitted carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Hironori [National Inst. of Materials and Chemical Research (NIMC), Ibaraki (Japan)

    1993-12-31

    Ways to halt global warming are being discussed worldwide. Global warming is an energy problem which is mainly attributed to the large volumes of carbon dioxide (CO{sub 2}) released into the atmosphere from the rapid increase in energy consumption since the Industrial Revolution. The basic solution to the problem, therefore, is to cut consumption of fossil fuels. To this end, it is important to promote energy conservation by improving the fuel efficiency of machines, as well as shift to energy sources that do not emit carbon dioxide and develop related technologies. If current trends in economic growth continue in the devloping world as well as the developed countries, there can be no doubt that energy consumption will increase. Therefore, alongside energy conservation and the development of alternative energies, the importance of technologies to recover and fix CO{sub 2} will increase in the fight against global warming.

  18. Carbon dioxide may become a resource

    International Nuclear Information System (INIS)

    Haugneland, Petter; Areklett, Ivar

    2002-01-01

    The greenhouse gas CO 2 may become a product that the oil companies would pay for. In an extensive international resource project methods for CO 2 capture, transport and storage are being investigated. CO 2 capture means that carbon dioxide that is formed in the combustion of fossil fuels is separated out from the process, either from the fuel (decarbonization), or from the flue gas, and then stored. The article briefly describes the international joint project CO 2 Capture Project (CCP), in which eight oil companies are participating. If one can find a method for injecting CO 2 into oil reservoirs that leads to increased oil production, then part of the extra cost of removing the carbon dioxide from flue gas may be repaid

  19. Direct carbon dioxide emissions from civil aircraft

    OpenAIRE

    Grote, Matt; Williams, Ian; Preston, John

    2014-01-01

    Global airlines consume over 5 million barrels of oil per day, and the resulting carbon dioxide (CO2) emitted by aircraft engines is of concern. This article provides a contemporary review of the literature associated with the measures available to the civil aviation industry for mitigating CO2 emissions from aircraft. The measures are addressed under two categories – policy and legal-related measures, and technological and operational measures. Results of the review are used to develop sever...

  20. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  1. Adsorption of water and carbon dioxide on hematite and consequences for possible hydrate formation.

    Science.gov (United States)

    Kvamme, Bjørn; Kuznetsova, Tatiana; Kivelae, Pilvi-Helina

    2012-04-07

    The interest in carbon dioxide for enhanced oil recovery is increasing proportional to the decline in naturally driven oil production and also due to the increasing demand for reduced emission of carbon dioxide into the atmosphere. Transport of carbon dioxide in offshore pipelines involves high pressure and low temperatures, conditions which may lead to formation of hydrates from residual water dissolved in carbon dioxide and carbon dioxide. The critical question is whether the water at certain temperatures and pressures will drop out as liquid droplets first, and then form hydrates, or alternatively, adsorb on the pipeline surfaces, and subsequently form hydrates heterogeneously. In this work, we used several different basis sets of density functional theory in ab initio calculations to estimate the charge distribution of hematite (the dominating component of rust) crystals. These rust particles were embedded in water and chemical potential for adsorbed water molecules was estimated through thermodynamic integration and compared to similar estimates for water clusters of the same size. While the generated charges were not unique, the use of high order approximations and different basis sets provides a range of likely charge distributions. Values obtained for the chemical potential of water in different surroundings indicated that it would be thermodynamically favorable for water to adsorb on hematite, and that evaluation of potential carbon dioxide hydrate formation conditions and kinetics should be based on this formation mechanism. Depending on the basis set and approximations, the estimated gain for water to adsorb on the hematite surface rather than condense as droplets varied between -1.7 kJ mole(-1) and -3.4 kJ mole(-1). The partial charge distribution on the hematite surface is incompatible with the hydrate structure, and thus hydrates will be unable to attach to the surface. The behavior of water outside the immediate vicinity of hematite (beyond 3

  2. Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Marvin, E-mail: marvin.kant@tu-berlin.de [Department of Entrepreneurship and Innovation Management, Technische Universität Berlin, Berlin (Germany)

    2017-09-13

    The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-)design of a dedicated support system are proposed on four levels: (a) actors, (b) resources, (c) institutional settings, and (d) the coordination of the support system.

  3. Fabrication of mesoporous cerium dioxide films by cathodic electrodeposition.

    Science.gov (United States)

    Kim, Young-Soo; Lee, Jin-Kyu; Ahn, Jae-Hoon; Park, Eun-Kyung; Kim, Gil-Pyo; Baeck, Sung-Hyeon

    2007-11-01

    Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templating agent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating.

  4. Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

    International Nuclear Information System (INIS)

    Kant, Marvin

    2017-01-01

    The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-)design of a dedicated support system are proposed on four levels: (a) actors, (b) resources, (c) institutional settings, and (d) the coordination of the support system.

  5. Biological effects data: Fluoride and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

    1975-04-01

    The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

  6. Carbon isotope ratios of atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Sakai, Hitoshi; Kishima, Noriaki; Tsutaki, Yasuhiro.

    1982-01-01

    The delta 13 C values relative to PDB were measured for carbon dioxide in air samples collected at various parts of Japan and at Mauna Loa Observatory, Hawaii in the periods of 1977 and 1978. The delta 13 C values of the ''clean air'' are -7.6 % at Hawaii and -8.1 per mille Oki and Hachijo-jima islands. These values are definitely lighter than the carbon isotope ratios (-6.9 per mille) obtained by Keeling for clean airs collected at Southern California in 1955 to 1956. The increase in 12 C in atmospheric carbon dioxide is attributed to the input of the anthropogenic light carbon dioxides (combustion of fossil fuels etc.) Taking -7.6 per mille to be the isotope ratio of CO 2 in the present clean air, a simple three box model predicts that the biosphere has decreased rather than increased since 1955, implying that it is acting as the doner of carbon rather than the sink. (author)

  7. Electrocatalytic process for carbon dioxide conversion

    Science.gov (United States)

    Masel, Richard I.; Salehi-Khojin, Amin; Kutz, Robert

    2017-11-14

    An electrocatalytic process for carbon dioxide conversion includes combining a Catalytically Active Element and a Helper Polymer in the presence of carbon dioxide, allowing a reaction to proceed to produce a reaction product, and applying electrical energy to said reaction to achieve electrochemical conversion of said carbon dioxide reactant to said reaction product. The Catalytically Active Element can be a metal in the form of supported or unsupported particles or flakes with an average size between 0.6 nm and 100 nm. The reaction products comprise at least one of CO, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, (COOH).sub.2, (COO.sup.-).sub.2, and CF.sub.3COOH.

  8. Carbon dioxide in Arctic and subarctic regions

    Energy Technology Data Exchange (ETDEWEB)

    Gosink, T. A.; Kelley, J. J.

    1981-03-01

    A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

  9. Synthesis and Characterization of Germanium Dioxide - Dioxide Waveguides

    Science.gov (United States)

    Chen, Din-Guo

    The increasing use of single mode fibers in local -area networks (LAN) and customer premises networks (CPN) will increase the need for passive optical components, such as branching devices, mixers, etc. Integrated optical devices are potentially ideal for these applications, provided that they can be made compatible with single mode fibers. The use of GeO_2 as the core dopant and SiO_2 as the substrate ensures that these waveguides will have virtually identical characteristics to single mode fibers. Additionally, glasses in the form of waveguides have recently been used to study various nonlinear optical phenomena, which provide great potential applications such as data storage and information processing. The present study has for the first time demonstrated the feasibility of employing both sol-gel multiple dip -coating and low pressure chemical vapor deposition (LPCVD) in the production of GeO_2-SiO _2 waveguiding films with various germania contents. The thin film characteristics were studied by various analytical techniques (e.g. ellipsometry, waveguiding Raman spectroscopy, FTIR, XPS, SEM/TEM, etc.). The composition dependence of the linear refractive index of GeO _2-SiO_2 films follows that predicted by the Lorenz-Lorenz model. Vibrational spectroscopy revealed the existence of Si-O-Ge linkages in GeO_2-SiO_2 glass network. The addition of GeO_2 in SiO_2 caused a decrease in the size of both the D1 and D2 defect bands in the SiO _2 Raman spectra. The structure of the LPCVD film appears to be dominated by D1 and D2 defect bands. Using a three-prism loss measurement technique, the propagation losses were found to be 3.31 dB/cm and 2.59dB/cm for sol-gel and LPCVD films, respectively. These losses are attributed to various scattering processes in the films. The mode indices of the waveguide were measured using a prism coupling technique. The measured mode indices were found to agree with the calculated value based upon a step-index profile assumption. The

  10. Sun protection enhancement of titanium dioxide crystals by the use of carnauba wax nanoparticles: the synergistic interaction between organic and inorganic sunscreens at nanoscale.

    Science.gov (United States)

    Villalobos-Hernández, J R; Müller-Goymann, C C

    2006-09-28

    Carnauba wax is partially composed of cinnamates. The rational combination of cinnamates and titanium dioxide has shown a synergistic effect to improve the sun protection factor (SPF) of cosmetic preparations. However, the mechanism of this interaction has not been fully understood. In this study, an ethanolic extract of the carnauba wax and an ethanolic solution of a typical cinnamate derivative, ethylcinnamate, were prepared and their UV absorption and SPF either alone or in the presence of titanium dioxide were compared. The titanium dioxide crystals and the cinnamates solutions were also distributed into a matrix composed of saturated fatty acids to emulate the structure of the crystallized carnauba wax. SPF, differential scanning calorimetry (DSC) and X-ray studies of these matrices were performed. Additionally, carnauba wax nanosuspensions containing titanium dioxide either in the lipid phase or in the aqueous phase were prepared to evaluate their SPFs and their physical structure. Strong UV absorption was observed in diluted suspensions of titanium dioxide after the addition of cinnamates. The saturated fatty acid matrices probably favored the adsorption of the cinnamates at the surface of titanium dioxide crystals, which was reflected by an increase in the SPF. No modification of the crystal structure of the fatty acid matrices was observed after the addition of cinnamates or titanium dioxide. The distribution of the titanium dioxide inside the lipid phase of the nanosuspensions was more effective to reach higher SPFs than that at the aqueous phase. The close contact between the carnauba wax and the titanium dioxide crystals after the high-pressure homogenization process was confirmed by transmission electron microscopy (TEM).

  11. Electronic structure of the chromium dioxide (001) surface

    NARCIS (Netherlands)

    Leuken, H. van; Groot, R.A. de

    1995-01-01

    Local-density calculations on the CrO2 (001) surface are reported. The half-metallic character of the bulk is found to be maintained at the surface. Surface states of oxygen p character at the top of the valence band for the semiconducting spin direction are discussed.

  12. Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge.

    Science.gov (United States)

    Xu, Shijing; Wang, Jingyao; Wu, Jiazhong; Liu, Qingjie; Sun, Chengzhen; Bai, Bofeng

    2018-04-19

    Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges. As the surface charge density exceeds a critical value of 0.992 e/nm 2 , the contact angle reaches up to 78.8° and the water-wet state is very apparent. The variation of contact angles can be confirmed from the number density distributions of oil molecules. With increasing the surface charge density, the adsorption of oil molecules weakens and the contact areas between nano-droplets and silicon dioxide surface are reduced. In addition, the number density distributions, RDF distributions, and molecular orientations indicate that the oil molecules are adsorbed on the silicon dioxide surface layer-by-layer with an orientation parallel to the surface. However, the layered structure of oil molecules near the silicon dioxide surface becomes more and more obscure at higher surface charge densities.

  13. Study of Soil Decontamination Method Using Supercritical Carbon Dioxide and TBP

    International Nuclear Information System (INIS)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung

    2014-01-01

    The result of this study means that we have a possible new method for cheap and less wasteful nuclear waste decontamination. When severe accidents such as the incident at the Fukushima nuclear site occur, the soil near the power plant is contaminated with fission products or the activation metal structure of the power plant. The soil pollution form depends on the environment and soil characteristics of the contaminated areas. Thus, a- single-decontamination method is not effective for site cleanup. In addition, some soil decontamination methods are expensive and large amounts of secondary waste are generated. Therefore, we need new soil decontamination methods. In this study, instead of using a conventional solvent method that generates secondary waste, supercritical carbon dioxide was used to remove metal ions from the soil. Supercritical carbon dioxide is known for good permeation characteristics. We expect that we will reduce the cost of soil pollution management. Supercritical carbon dioxide can decontaminate soil easily, as it has the ability to penetrate even narrow gaps with very good moisture permeability. We used TBP, which is a known for extractant of actinium metal. TBP is usually used for uranium and strontium extraction. Using TBP-HNO 3 complex and supercritical carbon dioxide, we did extraction experiments for several heavy metals in contaminated soil

  14. Study of Soil Decontamination Method Using Supercritical Carbon Dioxide and TBP

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung [Kyunghee Univ., Yongin (Korea, Republic of)

    2014-05-15

    The result of this study means that we have a possible new method for cheap and less wasteful nuclear waste decontamination. When severe accidents such as the incident at the Fukushima nuclear site occur, the soil near the power plant is contaminated with fission products or the activation metal structure of the power plant. The soil pollution form depends on the environment and soil characteristics of the contaminated areas. Thus, a- single-decontamination method is not effective for site cleanup. In addition, some soil decontamination methods are expensive and large amounts of secondary waste are generated. Therefore, we need new soil decontamination methods. In this study, instead of using a conventional solvent method that generates secondary waste, supercritical carbon dioxide was used to remove metal ions from the soil. Supercritical carbon dioxide is known for good permeation characteristics. We expect that we will reduce the cost of soil pollution management. Supercritical carbon dioxide can decontaminate soil easily, as it has the ability to penetrate even narrow gaps with very good moisture permeability. We used TBP, which is a known for extractant of actinium metal. TBP is usually used for uranium and strontium extraction. Using TBP-HNO{sub 3} complex and supercritical carbon dioxide, we did extraction experiments for several heavy metals in contaminated soil.

  15. Solid carbon dioxide to promote the extraction of extra-virgin olive oil

    Energy Technology Data Exchange (ETDEWEB)

    Zinnai, A.; Venturi, F.; Quartacci, V.F.; Sanmartin, C.; Favati, F.; Andrich, G.

    2016-07-01

    The use of solid carbon dioxide (dry ice) as a cryogen is widespread in the food industry to produce high quality wines, rich in color and perfumes. The direct addition of carbon dioxide to olives in the solid state before milling represents a fundamental step which characterizes this innovative extraction system. At room temperature conditions solid carbon dioxide evolves directly into the air phase (sublimation), and the direct contact between the cryogen and the olives induces a partial solidification of the cellular water inside the fruits. Since the volume occupied by water in the solid state is higher than that in the liquid state, the ice crystals formed are incompatible with the cellular structure and induce the collapse of the cells, besides promoting the diffusion of the cellular substances in the extracted oil, which is thus enriched with cellular metabolites characterized by a high nutraceutical value. Furthermore, a layer of CO2 remains over the olive paste to preserve it from oxidative degradation. The addition of solid carbon dioxide to processed olives induced a statistically significant increase in oil yield and promoted the accumulation of tocopherols in the lipid phase, whereas a not significant increase in the phenolic fraction of the oil occurred. (Author)

  16. Carbon dioxide emissions embodied in international trade in Central Europe between 1995 and 2008

    Directory of Open Access Journals (Sweden)

    Vlčková Jana

    2015-12-01

    Full Text Available Climate change and environmental policies are widely discussed, but much less is known about emissions embodied in goods traded internationally, and the distinction between emission producers and consumers. The carbon dioxide emissions embodied in international trade in Central European countries are subject to examination in this paper. As a result of industrial restructuring and environmental legislation, air pollution has improved significantly in Central European countries since the 1989 transition. On the other hand, economic growth has been accompanied by a rise in consumerism. Despite the increasing role of exports, the Visegrad group countries have become net importers of carbon dioxide emissions between 1995 and 2008. This seems to be the ‘standard trajectory’ of a country’s transition toward a more developed and consumption-oriented economy. The global patterns of carbon dioxide emissions embodied in manufacturing exports are also mapped, using network analysis and constructing ‘product space’. The analysis confirms that industrial re-structuring played an important role in lowering the production of carbon dioxide emissions in the Visegrad countries.

  17. High Rate Performance Nanocomposite Electrode of Mesoporous Manganese Dioxide/Silver Nanowires in KI Electrolytes

    Directory of Open Access Journals (Sweden)

    Yanhua Jiang

    2015-10-01

    Full Text Available In recent years, manganese dioxide has become a research hotspot as an electrode material because of its low price. However, it has also become an obstacle to industrialization due to its low ratio of capacitance and the low rate performance which is caused by the poor electrical conductivity. In this study, a KI solution with electrochemical activity was innovatively applied to the electrolyte, and we systematically investigated the rate performance of the mesoporous manganese dioxide and the composite electrode with silver nanowires in supercapacitors. The results showed that when mesoporous manganese dioxide and mesoporous manganese dioxide/silver nanowires composite were used as electrodes, the strength of the current was amplified five times (from 0.1 to 0.5 A/g, the remaining rates of specific capacitance were 95% (from 205.5 down to 197.1 F/g and 92% (from 208.1 down to 191.7 F/g in the KI electrolyte, and the rate performance was much higher than which in an Na2SO4 electrolyte with a remaining rate of 25% (from 200.3 down to 49.1 F/g and 60% (from 187.2 down to 113.1 F/g. The morphology and detail structure were investigated by Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry and Nitrogen adsorption-desorption isotherms. The electrochemical performance was assessed by cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy.

  18. The carbon dioxide thermometer and the cause of global warming

    International Nuclear Information System (INIS)

    Calder, Nigel

    1999-01-01

    Carbon dioxide in the air may be increasing because the world is warming. This possibility, which contradicts the hypothesis of an enhanced greenhouse warming driven by manmade emissions, is here pursued in two ways. First, increments in carbon dioxide are treated as readings of a natural thermometer that tracks global and hemispheric temperature deviations, as gauged by meteorologists' thermometers. Calibration of the carbon dioxide thermometer to conventional temperatures then leads to a history of carbon dioxide since 1856 that diverges from the ice-core record. Secondly, the increments of carbon dioxide can also be accounted for, without reference to temperature, by the combined effects of cosmic rays, El Nino and volcanoes. The most durable effect is due to cosmic rays. A solar wind history, used as a long-term proxy for the cosmic rays, gives a carbon dioxide history similar to that inferred from the global temperature deviations. (author)

  19. Amperometric sensor for carbon dioxide: design, characteristics, and perforance

    International Nuclear Information System (INIS)

    Evans, J.; Pletcher, D.; Warburton, P.R.G.; Gibbs, T.K.

    1989-01-01

    A new sensor for atmospheric carbon dioxide is described. It is an amperometric device based on a porous electrode in a three-electrode cell and the electrolyte is a copper diamine complex in aqueous potassium chloride. The platinum cathode, held at constant potential, is used to detect the formation of Cu 2+ following the change in the pH of the solution when the sensor is exposed to an atmosphere containing carbon dioxide. The sensor described is designed to monitor carbon dioxide concentrations in the range 0-5%, although with some modifications, other ranges would be possible. The response to a change in the carbon dioxide content of the atmosphere is rapid (about 10s) while the monitored current is strongly (but nonlinearly) dependent on carbon dioxide concentration. Unlike other amperometric devices for carbon dioxide, there is no interference from oxygen although other acid gases would lead to an interfering response

  20. Effects of carbon dioxide on Penicillium chrysogenum: an autoradiographic study

    International Nuclear Information System (INIS)

    Edwards, A.G.; Ho, C.S.

    1988-01-01

    Previous research has shown that dissolved carbon dioxide causes significant changes in submerged penicillin fermentations, such as stunted, swollen hyphae, increased branching, lower growth rates, and lower penicillin productivity. Influent carbon dioxide levels of 5 and 10% were shown through the use of autoradiography to cause an increase in chitin synthesis in submerged cultures of Penicillium chrysogenum. At an influent 5% carbon dioxide level, chitin synthesis is ca. 100% greater in the subapical region of P. chrysogenum hyphae than that of the control, in which there was no influent carbon dioxide. Influent carbon dioxide of 10% caused an increase of 200% in chitin synthesis. It is believed that the cell wall must be plasticized before branching can occur and that high amounts of dissolved carbon dioxide cause the cell to lose control of the plasticizing effect, thus the severe morphological changes occur

  1. Investigation of photocatalytic activity of titanium dioxide deposited on metallic substrates by DC magnetron sputtering

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Canulescu, Stela; Dirscherl, Kai

    2013-01-01

    The photocatalytic properties of titanium dioxide (TiO2) coating in the anatase crystalline structure deposited on aluminium AA1050 alloy and stainless steel S316L substrates were investigated. The coating was prepared by DC magnetron sputtering. The microstructure and surface morphology of the c......The photocatalytic properties of titanium dioxide (TiO2) coating in the anatase crystalline structure deposited on aluminium AA1050 alloy and stainless steel S316L substrates were investigated. The coating was prepared by DC magnetron sputtering. The microstructure and surface morphology...... sweep voltammetry, impedance measurements. The microstructure and surface morphology of the coating were similar irrespective of the nature of the substrate, while the photocatalytic behaviour was found to vary depending on the substrate type. In general the TiO2 coating on stainless steel was shown...

  2. Point Defects in 3D and 1D Nanomaterials: The Model Case of Titanium Dioxide

    International Nuclear Information System (INIS)

    Knauth, Philippe

    2010-01-01

    Titanium dioxide is one of the most important oxides for applications in energy and environment, such as solar cells, photocatalysis, lithium-ion batteries. In recent years, new forms of titanium dioxide with unusual structure and/or morphology have been developed, including nanocrystals, nanotubes or nanowires. We have studied in detail the point defect chemistry in nanocrystalline TiO 2 powders and ceramics. There can be a change from predominant Frenkel to Schottky disorder, depending on the experimental conditions, e.g. temperature and oxygen partial pressure. We have also studied the local environment of various dopants with similar ion radius, but different ion charge (Zn 2+ , Y 3+ , Sn 4+ , Zr 4+ , Nb 5+ ) in TiO 2 nanopowders and nanoceramics by Extended X-Ray Absorption Fine Structure (EXAFS) Spectroscopy. Interfacial segregation of acceptors was demonstrated, but donors and isovalent ions do not segregate. An electrostatic 'space charge' segregation model is applied, which explains well the observed phenomena.

  3. Adverse effects of the automotive industry on carbon dioxide emissions

    OpenAIRE

    Mpho Bosupeng

    2016-01-01

    This study aims to determine the effects of the automotive industry on carbon dioxide emissions for the period from 1997 to 2010 for diverse economies, as well as the relationships between carbon dioxide discharges and output. The study applies cointegration and causality tests to validate these associations. The results of the Johansen cointegration test depict long-run associations between the quantity of passenger cars and carbon dioxide emissions in France, Sweden, Spain, Hungary and Japa...

  4. On reaction of titanium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

    1986-01-01

    The reaction between titanium polonides and carbon dioxide has been studied by comparing titanium polonide thermal resistance in vacuum and in carbon dioxide. The investigation has shown that titanium mono- and semipolonides fail at temperatures below 350 deg C. Temperature dependence of polonium vapor pressure prepared at failure of the given polonides is determined by the radiotensiometry in carbon dioxide. Enthalpy calculated for this dependence is close to the enthalpy of elementary polonium evaporation in vacuum

  5. Supercritical carbon dioxide: a solvent like no other

    Directory of Open Access Journals (Sweden)

    Jocelyn Peach

    2014-08-01

    Full Text Available Supercritical carbon dioxide (scCO2 could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs. Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity.

  6. The removal of phenols from oily wastewater by chlorine dioxide

    OpenAIRE

    Hsu, Chung-Jung

    1988-01-01

    Treatability studies were performed on oily wastewaters produced by petroleum and canning industries. Chlorine dioxide was used for the removal of phenolic compounds from these oily wastewaters. Most of phenolic compounds can be destroyed by chlorine dioxide within 15 minutes if CI02-to-phenol ratios of higher than 5.0 are provided. Factors such as pH, temperature, and COD have little effect on phenol removal. The effectiveness of chlorine dioxide treatment depends critic...

  7. Investigation of the thermal decomposition of a new titanium dioxide material

    Czech Academy of Sciences Publication Activity Database

    Palkovská, Monika; Slovák, V.; Šubrt, Jan; Boháček, Jaroslav; Barbieriková, Z.; Brezová, V.; Fajgar, Radek

    2016-01-01

    Roč. 125, č. 3 (2016), s. 1071-1078 ISSN 1388-6150 R&D Projects: GA ČR(CZ) GA14-20744S; GA MŠk(CZ) 7AMB14SK178 Institutional support: RVO:61388980 ; RVO:67985858 Keywords : Titanium dioxide * Rod-shaped structure * Thermal analysis * Evolved gas analysis * EPR spectroscopy Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UCHP-M) Impact factor: 1.953, year: 2016

  8. Contribution to the study of the microstructure of uranium dioxide (1962)

    International Nuclear Information System (INIS)

    Porneuf, A.

    1960-05-01

    The microstructure of sintered uranium dioxide is studied in relation with several parameters, specially the sintering temperatures and atmospheres. The external surface and the internal microstructure of the sintered are examined, using fractography and ceramography. Various techniques for preparing surfaces (mechanical and electrolytic polishing) and for revealing the structure (chemical and anodic attack, ionic bombardment oxidation) have been experienced and compared. Patterns similar to those revealed in metals and probably related with interactions between dislocations and vacancies have been observed. (author) [fr

  9. Ultrafast Phase Transition in Vanadium Dioxide Driven by Hot-Electron Injection

    Directory of Open Access Journals (Sweden)

    Prasankumar R. P.

    2013-03-01

    Full Text Available We present a novel all-optical method of triggering the phase transition in vanadium dioxide by means of ballistic electrons injected across the interface between a mesh of Au nanoparticles coveringd VO2 nanoislands. By performing non-degenerate pump-probe transmission spectroscopy on this hybrid plasmonic/phase-changing nanostructure, structural and electronic dynamics can be retrieved and compared.

  10. Two Iron Complexes as Homogeneous and Heterogeneous Catalysts for the Chemical Fixation of Carbon Dioxide.

    Science.gov (United States)

    Karan, Chandan Kumar; Bhattacharjee, Manish

    2018-04-16

    Two new bimetallic iron-alkali metal complexes of amino acid (serine)-based reduced Schiff base ligand were synthesized and structurally characterized. Their efficacy as catalysts for the chemical fixation of carbon dioxide was explored. The heterogeneous version of the catalytic reaction was developed by the immobilization of these homogeneous bimetallic iron-alkali metal complexes in an anion-exchange resin. The resin-bound complexes can be used as recyclable catalysts up to six cycles.

  11. Radon, carbon dioxide and fault displacements in Central Europe related to the Tohoku earthquake

    Czech Academy of Sciences Publication Activity Database

    Briestenský, Miloš; Thinová, L.; Praksová, R.; Stemberk, Josef; Rowberry, Matthew David; Knejflová, Z.

    2014-01-01

    Roč. 160, 1-3 (2014), s. 78-82 ISSN 0144-8420 R&D Projects: GA MŠk LM2010008; GA ČR GAP210/12/0573 Institutional support: RVO:67985891 Keywords : carbon dioxide * radon * fault displacements * Tohoku earthquake Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.913, year: 2014 http://rpd.oxfordjournals.org/content/early/2014/04/06/rpd.ncu090

  12. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

  13. Selective free radical reactions using supercritical carbon dioxide.

    Science.gov (United States)

    Cormier, Philip J; Clarke, Ryan M; McFadden, Ryan M L; Ghandi, Khashayar

    2014-02-12

    We report herein a means to modify the reactivity of alkenes, and particularly to modify their selectivity toward reactions with nonpolar reactants (e.g., nonpolar free radicals) in supercritical carbon dioxide near the critical point. Rate constants for free radical addition of the light hydrogen isotope muonium to ethylene, vinylidene fluoride, and vinylidene chloride in supercritical carbon dioxide are compared over a range of pressures and temperatures. Near carbon dioxide's critical point, the addition to ethylene exhibits critical speeding up, while the halogenated analogues display critical slowing. This suggests that supercritical carbon dioxide as a solvent may be used to tune alkene chemistry in near-critical conditions.

  14. Mechanism of the toxic action of sulfur dioxide on plants

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaevskii, V S; Miroshnikova, A T; Firger, V V; Belokrylova, L M

    1975-01-01

    Experiments were performed to determine the effects of sulfur dioxide on U CO2 metabolism and photosynthesis in fescue and timothy grass and in maple and barberry branches. The free radical inhibitors, ascorbic acid and thiourea, were found to decrease the damaging effects of the sulfur dioxide. These results indicated that the processes involved are of the free-radical chain type. Even at low sulfur dioxide concentrations, photosphosphorylation and carbon dioxide assimilation were inhibited. In addition, starch and protein as well as the formation of polymeric substances were also inhibited.

  15. A Review on the Effects of Supercritical Carbon Dioxide on Enzyme Activity

    Directory of Open Access Journals (Sweden)

    Marie Zarevúcka

    2010-01-01

    Full Text Available Different types of enzymes such as lipases, several phosphatases, dehydrogenases, oxidases, amylases and others are well suited for the reactions in SC-CO2. The stability and the activity of enzymes exposed to carbon dioxide under high pressure depend on enzyme species, water content in the solution and on the pressure and temperature of the reaction system. The three-dimensional structure of enzymes may be significantly altered under extreme conditions, causing their denaturation and consequent loss of activity. If the conditions are less adverse, the protein structure may be largely retained. Minor structural changes may induce an alternative active protein state with altered enzyme activity, specificity and stability.

  16. Carbon Dioxide Separation Using Thermally Optimized Membranes

    Science.gov (United States)

    Young, J. S.; Jorgensen, B. S.; Espinoza, B. F.; Weimer, M. W.; Jarvinen, G. D.; Greenberg, A.; Khare, V.; Orme, C. J.; Wertsching, A. K.; Peterson, E. S.; Hopkins, S. D.; Acquaviva, J.

    2002-05-01

    The purpose of this project is to develop polymeric-metallic membranes for carbon dioxide separations that operate under a broad range of industrially relevant conditions not accessible with present membrane units. The last decade has witnessed a dramatic increase in the use of polymer membranes as an effective, economic and flexible tool for many commercial gas separations including air separation, the recovery of hydrogen from nitrogen, carbon monoxide, and methane mixtures, and the removal of carbon dioxide from natural gas. In each of these applications, high fluxes and excellent selectivities have relied on glassy polymer membranes which separate gases based on both size and solubility differences. To date, however, this technology has focused on optimizing materials for near ambient conditions. The development of polymeric materials that achieve the important combination of high selectivity, high permeability, and mechanical stability at temperatures significantly above 25oC and pressures above 10 bar, respectively, has been largely ignored. Consequently, there is a compelling rationale for the exploration of a new realm of polymer membrane separations. Indeed, the development of high temperature polymeric-metallic composite membranes for carbon dioxide separation at temperatures of 100-450 oC and pressures of 10-150 bar would provide a pivotal contribution with both economic and environmental benefits. Progress to date includes the first ever fabrication of a polymeric-metallic membrane that is selective from room temperature to 370oC. This achievement represents the highest demonstrated operating temperature at which a polymeric based membrane has successfully functioned. Additionally, we have generated the first polybenzamidizole silicate molecular composites. Finally, we have developed a technique that has enabled the first-ever simultaneous measurements of gas permeation and membrane compaction at elevated temperatures. This technique provides a unique

  17. Carbon dioxide and methane fluxes from arctic mudboils

    International Nuclear Information System (INIS)

    Wilson, K.S.; Humphreys, E.R.

    2010-01-01

    Carbon-rich ecosystems in the Arctic have large stores of soil carbon. However, small changes in climate have the potential to change the carbon (C) balance. This study examined how changes in ecosystem structure relate to differences in the exchange of greenhouse gases, notably carbon dioxide (CO 2 ) and methane (CH 4 ), between the atmosphere and soil. In particular, it examined low-center mudboils to determine the influence that this distinct form of patterned ground in the Arctic may have on the overall C balance of Tundra ecosystems. The net ecosystem exchange of carbon dioxide (NEE) was measured along with methane efflux along a 35-m transect intersecting two mudboils in a wet sedge fen in Canada's Southern Arctic during the summer of 2008. Mudboil features revealed significant variations in vegetation, soil temperature and thaw depth, and soil organic matter content along this transect. Variations in NEE were attributed to changes in the amount of vascular vegetation, but CO 2 and CH 4 effluxes were similar among the two mudboil and the sedge fen sampling areas. The study showed that vegetation played a key role in limiting temporal variations in CH 4 effluxes through plant mediated transport in both mudboil and sedge fen sampling areas. The negligible vascular plant colonization in one of the mudboils was likely due to more active frost heave processes. Growth and decomposition of cryptogamic organisms along with inflow of dissolved organic C and warmer soil temperatures may have been the cause of the rather high CO 2 and CH 4 efflux in this mudboil area.

  18. On the nature of the phase transition in uranium dioxide

    Science.gov (United States)

    Gofryk, K.; Mast, D.; Antonio, D.; Shrestha, K.; Andersson, D.; Stanek, C.; Jaime, M.

    Uranium dioxide (UO2) is by far the most studied actinide material as it is a primary fuel used in light water nuclear reactors. Its thermal and magnetic properties remain, however, a puzzle resulting from strong couplings between magnetism and lattice vibrations. UO2 crystalizes in the face-centered-cubic fluorite structure and is a Mott-Hubbard insulator with well-localized uranium 5 f-electrons. In addition, below 30 K, a long range antiferromagnetic ordering of the electric-quadrupole of the uranium moments is observed, forming complex non-collinear 3-k magnetic structure. This transition is accompanied by Jahn-Teller distortion of oxygen atoms. It is believed that the first order nature of the transition results from the competition between the exchange interaction and the Jahn-Teller distortion. Here we present results of our extensive thermodynamic investigations on well-characterized and oriented single crystals of UO2+x (x = 0, 0.033, 0.04, and 0.11). By focusing on the transition region under applied magnetic field we are able to study the interplay between different competing interactions (structural, magnetic, and electrical), its dynamics, and relationship to the oxygen content. We will discuss implications of these results. Work supported by the Department of Energy, Office of Basic Energy Sciences, Materials Sciences, and Engineering Division.

  19. Pyrochemical reduction of uranium dioxide and plutonium dioxide by lithium metal

    International Nuclear Information System (INIS)

    Usami, T.; Kurata, M.; Inoue, T.; Sims, H.E.; Beetham, S.A.; Jenkins, J.A.

    2002-01-01

    The lithium reduction process has been developed to apply a pyrochemical recycle process for oxide fuels. This process uses lithium metal as a reductant to convert oxides of actinide elements to metal. Lithium oxide generated in the reduction would be dissolved in a molten lithium chloride bath to enhance reduction. In this work, the solubility of Li 2 O in LiCl was measured to be 8.8 wt% at 650 deg. C. Uranium dioxide was reduced by Li with no intermediate products and formed porous metal. Plutonium dioxide including 3% of americium dioxide was also reduced and formed molten metal. Reduction of PuO 2 to metal also occurred even when the concentration of lithium oxide was just under saturation. This result indicates that the reduction proceeds more easily than the prediction based on the Gibbs free energy of formation. Americium dioxide was also reduced at 1.8 wt% lithium oxide, but was hardly reduced at 8.8 wt%

  20. Polarographic determination of uranium dioxide stoichiometry

    International Nuclear Information System (INIS)

    Viguie, J.; Uny, G.

    1966-10-01

    The method described allows the determination of small deviations from stoichiometry for uranium dioxide. It was applied to the study of surface oxidation of bulk samples. The sample is dissolved in phosphoric acid under an argon atmosphere; U(VI) is determined by polarography in PO 4 H 3 4.5 N - H 2 SO 4 4 N. U(IV) is determined by potentiometry. The detection limit is UO 2,0002 . The accuracy for a single determination at the 95% confidence level is ±20 per cent for samples with composition included between UO 2,001 and UO 2,01 . (authors) [fr

  1. Heat transfer coefficient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1998-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The calculated heat transfer coeeficient has been compared with the Chart correlation of Shah. The Chart Correlation predits too low heat transfer coefficient but the ratio...... between the measured and the calculated heat transfer coefficient is nearly constant and equal 1.9. With this factor the correlation predicts the measured data within 14% (RMS). The pressure drop is of the same order as the measuring uncertainty and the pressure drop has not been compared with correlation's....

  2. Carbon Dioxide Mitigation by Microalgal Photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Mijeong Lee; Gillis, James M.; Hwang, Jiann Yang [Michigan Technological University, Houghton (United States)

    2003-12-15

    Algal growth studies of Chlorella strains were conducted in a batch mode with bench type experiments. Carbon dioxide fixation rates of the following green microalgae were determined: Chlorella sp. H84, Chlorella sp. A2, Chlorella sorokiniana UTEX 1230, Chlorella vulgaris, and Chlorella pyrenoidosa. C. vulgaris, among other strains of microalgae, showed the highest growth rate (1.17 optical density/5 days). Cultivating conditions for C. vulgaris that produced the highest growth rate were at concentrations of 243 μg CO{sub 2}/mL, 10 mM ammonia, and 1 mM phosphate, with an initial pH range of 7-8.

  3. Nuclear power and carbon dioxide free automobiles

    International Nuclear Information System (INIS)

    Pendergast, D.R.

    1999-01-01

    Nuclear energy has been developed as a major source of electric power in Canada. Electricity from nuclear energy already avoids the emission of about 100 million tonnes of carbon dioxide to the atmosphere in Canada. This is a significant fraction of the 619 million tonnes of Canadian greenhouse gas emissions in 1995. However, the current scope of application of electricity to end use energy needs in Canada limits the contribution nuclear energy can make to carbon dioxide emission reduction. Nuclear energy can also contribute to carbon dioxide emissions reduction through expansion of the use of electricity to less traditional applications. Transportation, in particular contributed 165 million tonnes of carbon dioxide to the Canadian atmosphere in 1995. Canada's fleet of personal vehicles consisted of 16.9 million cars and light trucks. These vehicles were driven on average 21,000 km/year and generated 91 million tonnes of greenhouse gases expressed as a C02 equivalent. Technology to improve the efficiency of cars is under development which is expected to increase the energy efficiency from the 1995 level of about 10 litres/100 km of gasoline to under 3 litres/100km expressed as an equivalent referenced to the energy content of gasoline. The development of this technology, which may ultimately lead to the practical implementation of hydrogen as a portable source of energy for transportation is reviewed. Fuel supply life cycle greenhouse gas releases for several personal vehicle energy supply systems are then estimated. Very substantial reductions of greenhouse gas emissions are possible due to efficiency improvements and changing to less carbon intensive fuels such as natural gas. C02 emissions from on board natural gas fueled versions of hybrid electric cars would be decreased to approximately 25 million t/year from the current 91 million tonnes/year. The ultimate reduction identified is through the use of hydrogen fuel produced via electricity from CANDU power

  4. Method for Extracting and Sequestering Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Rau, Gregory H.; Caldeira, Kenneth G.

    2005-05-10

    A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO2 from a gaseous environment.

  5. Apparatus for extracting and sequestering carbon dioxide

    Science.gov (United States)

    Rau, Gregory H [Castro Valley, CA; Caldeira, Kenneth G [Livermore, CA

    2010-02-02

    An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

  6. Ultrathin, epitaxial cerium dioxide on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Flege, Jan Ingo, E-mail: flege@ifp.uni-bremen.de; Kaemena, Björn; Höcker, Jan; Schmidt, Thomas; Falta, Jens [Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen (Germany); Bertram, Florian [Photon Science, Deutsches Elektronensynchrotron (DESY), Notkestraße 85, 22607 Hamburg (Germany); Wollschläger, Joachim [Department of Physics, University of Osnabrück, Barbarastraße 7, 49069 Osnabrück (Germany)

    2014-03-31

    It is shown that ultrathin, highly ordered, continuous films of cerium dioxide may be prepared on silicon following substrate prepassivation using an atomic layer of chlorine. The as-deposited, few-nanometer-thin Ce{sub 2}O{sub 3} film may very effectively be converted at room temperature to almost fully oxidized CeO{sub 2} by simple exposure to air, as demonstrated by hard X-ray photoemission spectroscopy and X-ray diffraction. This post-oxidation process essentially results in a negligible loss in film crystallinity and interface abruptness.

  7. Advanced Rechargeable Lithium Sulfur Dioxide Cell

    Science.gov (United States)

    1991-11-01

    AD-A274 908IIIIlIIIE McDonald , P. Harris, F. Goebel, S. Hossi ierra, M. Guentert, C. Todino 7 ad r nse TECHNICAL PRODUCTS INCY DTIC ELECTE JAN26 1994...Pawcatuck, CT 06379 94-02298 1425 Best Available Copy I ADVANCED RECHARGEABLE LITHIUM SULFUR DIOXIDE CELL I R.C. McDonald , P. Harris, F. Goebel, S. Hossain...20 minutes. The electrochemical measurements were carried out using a I Starbuck 20-station cycler system which is connected to a computer to monitor

  8. Nuclear energy significantly reduces carbon dioxide emissions

    International Nuclear Information System (INIS)

    Koprda, V.

    2006-01-01

    This article is devoted to nuclear energy, to its acceptability, compatibility and sustainability. Nuclear energy is non-dispensable part of energy sources with vast innovation potential. The safety of nuclear energy, radioactive waste deposition, and prevention of risk from misuse of nuclear material have to be very seriously adjudged and solved. Nuclear energy is one of the ways how to decrease the contamination of atmosphere with carbon dioxide and it solves partially also the problem of global increase of temperature and climate changes. Given are the main factors responsible for the renaissance of nuclear energy. (author)

  9. The carbon dioxide capture and geological storage

    International Nuclear Information System (INIS)

    2006-06-01

    This road-map proposes by the Group Total aims to inform the public on the carbon dioxide capture and geological storage. One possible means of climate change mitigation consists of storing the CO 2 generated by the greenhouse gases emission in order to stabilize atmospheric concentrations. This sheet presents the CO 2 capture from lage fossil-fueled combustion installations, the three capture techniques and the CO 2 transport options, the geological storage of the CO 2 and Total commitments in the domain. (A.L.B.)

  10. Characterization of transport properties in uranium dioxide: the case of the oxygen auto-diffusion

    International Nuclear Information System (INIS)

    Fraczkiewicz, M.; Baldinozzi, G.

    2008-01-01

    Point defects in uranium dioxide which control the transport phenomena are still badly known. The aim of this work is to show how in carrying out several experimental techniques, it is possible to demonstrate both the existence and to determine the nature (charge and localization) of predominant defects responsible of the transport phenomena in a fluorite-type structure oxide. The oxygen diffusion in the uranium dioxide illustrates this. In the first part of this work, the accent is put on the electric properties of uranium dioxide and more particularly on the variation laws of the electric conductivity in terms of temperature, of oxygen potential and of the impurities amounts present in the material. These evolutions are connected to point and charged complex defects models and the pertinence of these models is discussed. Besides, it is shown how the electric conductivity measurements can allow to define oxygen potential domains in which the concentrations in electronic carriers are controlled. This characterization being made, it is shown that the determination of the oxygen intrinsic diffusion coefficient and particularly its dependence to the oxygen potential and to the amount of impurity, allows to determine the main defect responsible to the atomic diffusion as well as its nature and its charge. In the second part, the experimental techniques to determine the oxygen diffusion coefficient are presented: there are the isotopic exchange technique for introducing the tracer in the material, and two techniques to characterize the diffusion profiles (SIMS and NRA). Examples of preliminary results are given for mono and polycrystalline samples. At last, from this methodology on uranium dioxide, studies considered to quantify the thermal and physicochemical effects are presented. Experiments considered with the aim to characterize the radiation diffusion in uranium dioxide are presented too. (O.M.)

  11. Carbon dioxide emissions reduction in China's transport sector: A dynamic VAR (vector autoregression) approach

    International Nuclear Information System (INIS)

    Xu, Bin; Lin, Boqiang

    2015-01-01

    Energy saving and carbon dioxide emission reduction in China is attracting increasing attention worldwide. At present, China is in the phase of rapid urbanization and industrialization, which is characterized by rapid growth of energy consumption. China's transport sector is highly energy-consuming and pollution-intensive. Between 1980 and 2012, the carbon dioxide emissions in China's transport sector increased approximately 9.7 times, with an average annual growth rate of 7.4%. Identifying the driving forces of the increase in carbon dioxide emissions in the transport sector is vital to developing effective environmental policies. This study uses Vector Autoregressive model to analyze the influencing factors of the changes in carbon dioxide emissions in the sector. The results show that energy efficiency plays a dominant role in reducing carbon dioxide emissions. Private vehicles have more impact on emission reduction than cargo turnover due to the surge in private car population and its low energy efficiency. Urbanization also has significant effect on carbon dioxide emissions because of large-scale population movements and the transformation of the industrial structure. These findings are important for the relevant authorities in China in developing appropriate energy policy and planning for the transport sector. - Highlights: • The driving forces of CO 2 emissions in China's transport sector were investigated. • Energy efficiency plays a dominant role in reducing carbon dioxide emissions. • Urbanization has significant effect on CO 2 emissions due to large-scale migration. • The role of private cars in reducing emissions is more important than cargo turnover

  12. Ocean Acidification: Investigation and Presentation of the Effects of Elevated Carbon Dioxide Levels on Seawater Chemistry and Calcareous Organisms

    Science.gov (United States)

    Buth, Jeffrey M.

    2016-01-01

    Ocean acidification refers to the process by which seawater absorbs carbon dioxide from the atmosphere, producing aqueous carbonic acid. Acidic conditions increase the solubility of calcium carbonate, threatening corals and other calcareous organisms that depend on it for protective structures. The global nature of ocean acidification and the…

  13. Investigation of silicon/silicon germanium multiple quantum well layers in silicon avalanche photodiodes

    International Nuclear Information System (INIS)

    Loudon, A.Y.

    2002-01-01

    Silicon single photon avalanche diodes (SPADs) are currently utilised in many single photon counting systems due to their high efficiency, fast response times, low voltage operation and potentially low cost. For fibre based applications however (at wavelengths 1.3 and 1.55μm) and eye-safe wavelength applications (>1.4μm), Si devices are not suitable due to their 1.1μm absorption edge and hence greatly reduced absorption above this wavelength. InGaAs/InP or Ge SPADs absorb at these longer wavelengths, but both require cryogenic cooling for low noise operation and III-V integration with conventional Si circuitry is difficult. Si/SiGe is currently attracting great interest for optoelectronic applications and attempts to combine Si avalanche photodiodes with Si/SiGe multiple quantum well absorbing layers have been successful. Here, an effort to utilise this material system has shown an improvement in photon counting efficiency above 1.1μm of more than 30 times compared to an all-Si control device. In addition to its longer wavelength response, this Si/SiGe device has room temperature operation, low cost fabrication and is compatible with conventional Si circuitry. (author)

  14. Continuous Process for the Etching, Rinsing and Drying of MEMS Using Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Min, Seon Ki; Han, Gap Su; You, Seong-sik [Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2015-10-15

    The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-CO{sub 2} (supercritical-CO{sub 2}) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-CO{sub 2}. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-CO{sub 2} without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, 25 .deg. C) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, 5 .deg. C), we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-CO{sub 2} (7.5 Mpa, 40 .deg. C), we had as good results as those of the case using gas-CO{sub 2}. Besides the processing time was shortened compared with that of the case of using gas-CO{sub 2}.

  15. BILP-19-An Ultramicroporous Organic Network with Exceptional Carbon Dioxide Uptake.

    Science.gov (United States)

    Klumpen, Christoph; Radakovitsch, Florian; Jess, Andreas; Senker, Jürgen

    2017-08-12

    Porous benzimidazole-based polymers (BILPs) have proven to be promising for carbon dioxide capture and storage. The polarity of their chemical structure in combination with an inherent porosity allows for adsorbing large amounts of carbon dioxide in combination with high selectivities over unpolar guest molecules such as methane and nitrogen. For this reason, among purely organic polymers, BILPs contain some of the most effective networks to date. Nevertheless, they are still outperformed by competitive materials such as metal-organic frameworks (MOFs) or metal doped porous polymers. Here, we report the synthesis of BILP-19 and its exceptional carbon dioxide uptake of up to 6 mmol•g-1 at 273 K, making the network comparable to state-of-the-art materials. BILP-19 precipitates in a particulate structure with a strongly anisotropic growth into platelets, indicating a sheet-like structure for the network. It exhibits only a small microporous but a remarkable ultra-microporous surface area of 144 m2•g-1 and 1325 m2•g-1, respectively. We attribute the exceptional uptake of small guest molecules such as carbon dioxide and water to the distinct ultra-microporosity. Additionally, a pronounced hysteresis for both guests is observed, which in combination with the platelet character is probably caused by an expansion of the interparticle space, creating additional accessible ultra-microporous pore volume. For nitrogen and methane, this effect does not occur which explains their low affinity. In consequence, Henry selectivities of 123 for CO2/N2 at 298 K and 12 for CO2/CH4 at 273 K were determined. The network was carefully characterized with solid-state nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, thermal gravimetry (TG) and elemental analyses as well as physisorption experiments with Ar, N2, CO2, CH4 and water.

  16. Use of supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Masayuki (Niigata Univ., Faculty of Engineering, Niigata, (Japan))

    1989-09-25

    Supercritical fluid extraction is a novel diffusion and separation technique which exploits simultaneously the increase of vapor pressure and the difference of chemical affinities of fluids near the critical point. A solvent which is used as the supercritical fluid has the following features: the critical point exists in the position of relatively ease of handling, the solvent is applicable to the extraction of a physiological active substance of thermal instability. Carbon dioxide as the solvent is non-flammable, non-corrosive, non-toxic, cheap, and readily available of high purity. The results of studies on the use of supercritical carbon dioxide (SC-CO{sub 2}) as a solvent for natural products in the fermentation and food industries, were collected. SC-CO{sub 2} extraction are used in many fields, examples for the application are as follows: removal of organic solvents from antibiotics; extraction of vegetable oils contained in wheat germ oil, high quality mustard seeds, rice bran and so on; brewing of sake using rice and rice-koji; use as a non-aqueous medium for the synthesis of precursors of the Aspartame; and use in sterilization. 66 refs., 17 figs., 21 tabs.

  17. Integrated Assessment of Carbon Dioxide Removal

    Science.gov (United States)

    Rickels, W.; Reith, F.; Keller, D.; Oschlies, A.; Quaas, M. F.

    2018-03-01

    To maintain the chance of keeping the average global temperature increase below 2°C and to limit long-term climate change, removing carbon dioxide from the atmosphere (carbon dioxide removal, CDR) is becoming increasingly necessary. We analyze optimal and cost-effective climate policies in the dynamic integrated assessment model (IAM) of climate and the economy (DICE2016R) and investigate (1) the utilization of (ocean) CDR under different climate objectives, (2) the sensitivity of policies with respect to carbon cycle feedbacks, and (3) how well carbon cycle feedbacks are captured in the carbon cycle models used in state-of-the-art IAMs. Overall, the carbon cycle model in DICE2016R shows clear improvements compared to its predecessor, DICE2013R, capturing much better long-term dynamics and also oceanic carbon outgassing due to excess oceanic storage of carbon from CDR. However, this comes at the cost of a (too) tight short-term remaining emission budget, limiting the model suitability to analyze low-emission scenarios accurately. With DICE2016R, the compliance with the 2°C goal is no longer feasible without negative emissions via CDR. Overall, the optimal amount of CDR has to take into account (1) the emission substitution effect and (2) compensation for carbon cycle feedbacks.

  18. Methanation of hydrogen and carbon dioxide

    International Nuclear Information System (INIS)

    Burkhardt, Marko; Busch, Günter

    2013-01-01

    Highlights: • The biologic methanation of exclusively gases like hydrogen and carbon dioxide is feasible. • Electrical energy can be stored in the established gas grid by conversion to methane. • The quality of produced biogas is very high (c CH4 = 98 vol%). • The conversion rate is depending on H 2 -flow rate. - Abstract: A new method for the methanation of hydrogen and carbon dioxide is presented. In a novel anaerobic trickle-bed reactor, biochemical catalyzed methanation at mesophilic temperatures and ambient pressure can be realized. The conversion of gaseous substrates by immobilized hydrogenotrophic methanogens is a unique feature of this reactor type. The already patented reactor produces biogas which has a very high quality (c CH4 = 97.9 vol%). Therefore, the storage of biogas in the existing natural gas grid is possible without extensive purification. The specific methane production was measured with P = 1.17 Nm CH4 3 /(m R 3 d). It is conceivable to realize the process at sites that generate solar or wind energy and sites subject to the conditions for hydrogen electrolysis (or other methods of hydrogen production). The combination with conventional biogas plants under hydrogen addition to methane enrichment is possible as well. The process enables the coupling of various renewable energy sources

  19. Studies on carbon dioxide power plant, (3)

    International Nuclear Information System (INIS)

    Akagawa, Koji; Fujii, Terushige; Sakaguchi, Tadashi; Kawabata, Yasusuke; Kuroda, Toshihiro.

    1980-01-01

    A power generating plant using carbon dioxide instead of water has been studied by the authors, as high efficiency can be obtained in high temperature range (higher than 650 deg C) and turbines become compact as compared with the Rankine steam cycle. In this paper, the theoretical analysis of the dynamic characteristics of this small power generating plant of supercritical pressure and the comparison with the experimental results are reported. In the theoretical analysis, the linear approximation method using small variation method was adopted for solution. Every component was modeled as the concentrated constant system, and the transfer function for each component was determined, then simulation was carried out for the total system synthesizing these components. The approximation of physical values, and the analysis of a plunger pump, a regenerator, a heater, a vapor valve, a turbine and a blower, piping, and pressure drop are described. The response to the stepwise changes of heating, flow rate, opening of a vapor valve and a load control valve for a blower was investigated. The theoretical anaysis and the experimental results were in good agreement, and this analysis is applicable to the carbon dioxide plant of practical scale. (Kako, I.)

  20. Design of a Uranium Dioxide Spheroidization System

    Science.gov (United States)

    Cavender, Daniel P.; Mireles, Omar R.; Frendi, Abdelkader

    2013-01-01

    The plasma spheroidization system (PSS) is the first process in the development of tungsten-uranium dioxide (W-UO2) fuel cermets. The PSS process improves particle spherocity and surface morphology for coating by chemical vapor deposition (CVD) process. Angular fully dense particles melt in an argon-hydrogen plasma jet at between 32-36 kW, and become spherical due to surface tension. Surrogate CeO2 powder was used in place of UO2 for system and process parameter development. Particles range in size from 100 - 50 microns in diameter. Student s t-test and hypothesis testing of two proportions statistical methods were applied to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders show great than 800% increase in the number of spherical particles over the stock powder with the mean spherocity only mildly improved. It is recommended that powders be processed two-three times in order to reach the desired spherocity, and that process parameters be optimized for a more narrow particles size range. Keywords: spherocity, spheroidization, plasma, uranium-dioxide, cermet, nuclear, propulsion

  1. Nanomaterial Case Studies: Nanoscale Titanium Dioxide in ...

    Science.gov (United States)

    EPA announced the availability of the final report, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen. This report is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: (1) as an agent for removing arsenic from drinking water; and (2) as an active ingredient in topical sunscreen. These case studies are organized around a comprehensive environmental assessment (CEA) framework that combines a product life cycle perspective with the risk assessment paradigm. They are intended to help identify what may need to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. These “case studies” do not represent completed or even preliminary assessments, nor are they intended to serve as a basis for risk management decisions in the near term on these specific uses of nano TiO2. Rather, the intent is to use this document in developing the scientific and technical information needed for future assessment efforts.

  2. Molecular and physiological responses to titanium dioxide ...

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that exposure to either nanoparticle altered the transcriptomes of rosette leaves and roots, with comparatively larger numbers of differentially expressed genes (DEGs) found under nano-titania exposure. Nano-titania induced more DEGs in rosette leaves, whereas roots had more DEGs under nano-ceria exposure. MapMan analyses indicated that while nano-titania up-regulated overall and secondary metabolism in both tissues, metabolic processes under nano-ceria remained mostly unchanged. Gene enrichment analysis indicated that both nanoparticles mainly enriched ontology groups such as responses to stress (abiotic and biotic), and defense responses (pathogens), and responses to endogenous stimuli (hormones). Nano-titania specifically induced genes associated with photosynthesis, whereas nano-ceria induced expression of genes related to activating transcription factors, most notably those belonging to the ethylene responsive element binding protein family. Interestingly, there were also increased numbers of rosette leaves and plant biomass under nano-ceria exposure, but not under nano-titania. Other transcriptomic responses did not clearly relate to responses observed at the organism level. This may b

  3. Adaptation to carbon dioxide tax in shipping

    International Nuclear Information System (INIS)

    Olsen, Kristian

    2000-01-01

    This note discusses the consequences for the sea transport sector between Norway and continental Europe of levying a carbon dioxide tax on international bunker. The influence of such a tax on the operational costs of various types of ship and various transport routes is calculated. The profit obtainable from the following ways of adapting to an increased tax level is assessed: (1) Reducing the speed, (2) Rebuilding the engine to decrease fuel consumption, (3) Changing the design speed for new ships. It is found that a carbon dioxide tax of NOK 200 per tonne of CO 2 will increase the transport costs by 3 - 15 percent. In the long run much of this may be transferred to the freight rates since so much of the sea transport are in segments in which the demand for the service is not sensitive to the prices. Even if the freight rates are not changed, a tax this size will not make it necessary to reduce the speed of the existing fleet. The income lost by taking fewer trips will exceed the costs saved in reducing the speed. However, the optimum design speed for new ships may be somewhat reduced (0.5 knots). Rebuilding engines to reduce the fuel consumption would pay off were it not for the fact that the remaining life of the present fleet is probably too short for this to be interesting

  4. The effect of alkaline cations on the Intercalation of Carbon Dioxide in Sepiolite Minerals: a Molecular Dynamics Investigation.

    Science.gov (United States)

    Tavanti, Francesco; Muniz-Miranda, Francesco; Pedone, Alfonso

    2018-03-01

    The ability of the sepiolite mineral to intercalate CO2 molecules inside its channels in the presence of different alkaline cations (K+, Na+ and Li+) has been studied by classical Molecular Dynamics simulations. Starting from an alkaline-free sepiolite crystalline model we built three models with stoichiometry Mg320Si440Al40O1200(OH)160X+40•480H2O. On these models, we gradually replaced the water molecules present in the channels with carbon dioxide and determined the energy of this exchange reaction as well as the structural organization and dynamics of carbon dioxide in the channels. The adsorption energy shows that the Li-containing sepiolite mineral retains more carbon dioxide with respect to those with sodium and potassium cations in the channels. Moreover, the ordered patterns of CO2 molecules observed in the alkaline-free sepiolite mineral are in part destabilized by the presence of cations decreasing the adsorption capacity of this clay mineral.

  5. [The clinical application of zirconium-dioxide-ceramics. Case report].

    Science.gov (United States)

    Somfai, Dóra; Zsigmond, Ágnes; Károlyházy, Katalin; Kispély, Barbara; Hermann, Péter

    2015-12-01

    Due to its outstanding physical, mechanical and esthetic properties, zirconium-dioxide is one of the most popular non-metal denture, capable of surpassing PFM in most cases. The recent advances of CAD/CAM technology makes it a good alternitve. Here we show the usefulness of zirconium-dioxide in everyday dental practice through three case reports.

  6. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

    2001-07-01

    Sodium based sorbents including sodium carbonate may be used to capture carbon dioxide from flue gas. A relatively concentrated carbon dioxide stream may be recoverable for sequestration when the sorbent is regenerated. Electrobalance tests indicated that sodium carbonate monohydrate was formed in a mixture of helium and water vapor at temperatures below 65 C. Additional compounds may also form, but this could not be confirmed. In the presence of carbon dioxide and water vapor, both the initial reaction rate of sodium carbonate with carbon dioxide and water and the sorbent capacity decreased with increasing temperature, consistent with the results from the previous quarter. Increasing the carbon dioxide concentration at constant temperature and water vapor concentration produced a measurable increase in rate, as did increasing the water vapor concentration at constant carbon dioxide concentration and temperature. Runs conducted with a flatter TGA pan resulted in a higher initial reaction rate, presumably due to improved gas-solid contact, but after a short time, there was no significant difference in the rates measured with the different pans. Analyses of kinetic data suggest that the surface of the sodium carbonate particles may be much hotter than the bulk gas due to the highly exothermic reaction with carbon dioxide and water, and that the rate of heat removal from the particle may control the reaction rate. A material and energy balance was developed for a cyclic carbonation/calcination process which captures about 26 percent of the carbon dioxide present in flue gas available at 250 C.

  7. Flexible substrates as basis for photocatalytic reduction of carbon dioxide

    DEFF Research Database (Denmark)

    Jensen, Jacob; Mikkelsen, Mette; Krebs, Frederik C

    2011-01-01

    A photocatalytic system for converting carbon dioxide into carbon monoxide was designed and constructed. The system relies on thin films of the photocatalyst prepared at low temperature using spray coating. We formulated inks based on the well-known photocatalyst titanium dioxide and characterized...

  8. Carbon Dioxide and Global Warming: A Failed Experiment

    Science.gov (United States)

    Ribeiro, Carla

    2014-01-01

    Global warming is a current environmental issue that has been linked to an increase in anthropogenic carbon dioxide in the atmosphere. To raise awareness of the problem, various simple experiments have been proposed to demonstrate the effect of carbon dioxide on the planet's temperature. This article describes a similar experiment, which…

  9. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  10. Conversion of metal plutonium to plutonium dioxide by pyrochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Panov, A.V.; Subbotin, V.G. [Russian Federal Nuclear Center, ALL-Russian Science and Research Institute of Technical Physics, Snezhinsk (Russian Federation); Mashirev, V.P. [ALL-Russian Science and Research Institute of Chemical Technology, Moscow (Russian Federation)

    2000-07-01

    Report contains experimental results on metal plutonium of weapon origin samples conversion to plutonium dioxide by pyrochemical method. Circuits of processes are described. Their advantages and shortcomings are shown. Parameters of plutonium dioxide powders (phase and fraction compositions, poured density) manufactured by pyrochemical method in RFNC-VNIITF are shown as well. (authors)

  11. Classification of titanium dioxide; Clasificacion del dioxido de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Macias B, L.R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Garcia C, R.M.; Maya M, M.E. [Secretaria de Hacienda y Credito Publico de Mexico, Mexico (Mexico); Ita T, A. De [Universidad Autonoma Metropolitana Azcapotzalco, Mexico (Mexico); Palacios G, J. [Instituto Politecnico Nacional (Mexico)

    2002-07-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO{sub 2}. The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  12. Model studies of limitation of carbon dioxide emissions reduction

    International Nuclear Information System (INIS)

    1992-01-01

    The report consists of two papers concerning mitigation of CO 2 emissions in Sweden, ''Limitation of carbon dioxide emissions. Socio-economic effects and the importance of international coordination'', and ''Model calculations for Sweden's energy system with carbon dioxide limitations''. Separate abstracts were prepared for both of the papers

  13. Balance and forecasts of french carbon dioxide emissions

    International Nuclear Information System (INIS)

    1992-11-01

    This paper strikes the balance of carbon dioxide emissions in France between 1986 and 1991 and gives forecasts till 2010. Since 1986, France has reduced its efforts for energy conservation and air pollution by carbon dioxide begins to growth again in connection with consumption growth in transport area, development of computer and simulation needs

  14. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1676 Section 52.1676 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347...

  15. 40 CFR 52.1576 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1576 Section 52.1576 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  16. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1876 Section 52.1876 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan...

  17. Fixation of carbon dioxide into dimethyl carbonate over ...

    Science.gov (United States)

    A titanium-based zeolitic thiophene-benzimidazolate framework has been designed for the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. The developed catalyst activates carbon dioxide and delivers over 16% yield of DMC without the use of any dehydrating agent or requirement for azeotropic distillation. Prepared for submission to Nature Scientific reports.

  18. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    Science.gov (United States)

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  19. Capacitance-Assisted Sustainable Electrochemical Carbon Dioxide Mineralisation.

    Science.gov (United States)

    Lamb, Katie J; Dowsett, Mark R; Chatzipanagis, Konstantinos; Scullion, Zhan Wei; Kröger, Roland; Lee, James D; Aguiar, Pedro M; North, Michael; Parkin, Alison

    2018-01-10

    An electrochemical cell comprising a novel dual-component graphite and Earth-crust abundant metal anode, a hydrogen producing cathode and an aqueous sodium chloride electrolyte was constructed and used for carbon dioxide mineralisation. Under an atmosphere of 5 % carbon dioxide in nitrogen, the cell exhibited both capacitive and oxidative electrochemistry at the anode. The graphite acted as a supercapacitive reagent concentrator, pumping carbon dioxide into aqueous solution as hydrogen carbonate. Simultaneous oxidation of the anodic metal generated cations, which reacted with the hydrogen carbonate to give mineralised carbon dioxide. Whilst conventional electrochemical carbon dioxide reduction requires hydrogen, this cell generates hydrogen at the cathode. Carbon capture can be achieved in a highly sustainable manner using scrap metal within the anode, seawater as the electrolyte, an industrially relevant gas stream and a solar panel as an effective zero-carbon energy source. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  20. Adverse effects of the automotive industry on carbon dioxide emissions

    Directory of Open Access Journals (Sweden)

    Mpho Bosupeng

    2016-05-01

    Full Text Available This study aims to determine the effects of the automotive industry on carbon dioxide emissions for the period from 1997 to 2010 for diverse economies, as well as the relationships between carbon dioxide discharges and output. The study applies cointegration and causality tests to validate these associations. The results of the Johansen cointegration test depict long-run associations between the quantity of passenger cars and carbon dioxide emissions in France, Sweden, Spain, Hungary and Japan. In addition, significant relations were observed between output and carbon dioxide discharges in Spain, Canada, India and Japan. Changes in output had substantial impact on emissions in Germany, Canada and India. The results also show that the number of passenger cars influences the magnitude of emissions in multiple economies. In conclusion, the automotive industry has to be considered in policies that aim to reduce carbon dioxide emissions.

  1. Carbon dioxide for enhanced oil recovery in Canada

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, S.; Manbybura, F.; Sparks, N.

    1985-01-01

    This paper examines the potential for carbon dioxide as a major miscible solvent in Canada and describes Shell Canada's carbon dioxide exploration efforts over the last few years. Enhanced oil recovery, specifically miscible flooding, has been recognized as a technically and economically feasible method for adding reserves and productive capacity to Canada's light and medium oil. The fiscal regime has been altered by both the federal and provincial governments to encourage miscible flooding development. As a result many projects have been initiated with others being evaluated and designed. This paper analyzes the history and the direction of miscible flooding in the United States, where carbon dioxide is becoming the predominant miscible solvent. The potential for future use of carbon dioxide in Canada is specifically addressed: potential oil recovery solvent supply, and economics. Shell's carbon dioxide exploration play currently underway is also discussed.

  2. Carbon dioxide from fossil fuels: adapting to uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K; Winter, R C; Bergman, M K

    1980-12-01

    If present scientific information is reasonable, the world is likely to experience noticeable global warming by the beginning of the next century if high annual growth rates of fossil-fuel energy use continue. Only with optimistic assumptions and low growth rates will carbon-dioxide-induced temperature increases be held below 2/sup 0/C or so over the next century. Conservation, flexible energy choices, and control options could lessen the potential effects of carbon dioxide. Though perhaps impractical from the standpoint of costs and efficiency losses, large coastal centralized facilities would be the most amenable to carbon dioxide control and disposal. Yet no country can control carbon dioxide levels unilaterally. The USA, however, which currently contributes over a quarter of all fossil-fuel carbon dioxide emissions and possesses a quarter of the world's coal resources, could provide a much needed role in leadership, research and education. 70 references.

  3. Carbon dioxide stripping in aquaculture. part 1: terminology and reporting

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ⇔ H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (<2000 μeq/kg), the difference between the true and apparent removal is small and can be ignored for many applications. Analytical and reporting standards are recommended to improve our understanding of carbon dioxide removal.

  4. Carbon Dioxide Detection and Indoor Air Quality Control.

    Science.gov (United States)

    Bonino, Steve

    2016-04-01

    When building ventilation is reduced, energy is saved because it is not necessary to heat or cool as much outside air. Reduced ventilation can result in higher levels of carbon dioxide, which may cause building occupants to experience symptoms. Heating or cooling for ventilation air can be enhanced by a DCV system, which can save energy while providing a comfortable environment. Carbon dioxide concentrations within a building are often used to indicate whether adequate fresh air is being supplied to the building. These DCV systems use carbon dioxide sensors in each space or in the return air and adjust the ventilation based on carbon dioxide concentration; the higher the concentration, the more people occupy the space relative to the ventilation rate. With a carbon dioxide sensor DCV system, the fresh air ventilation rate varies based on the number ofpeople in the space, saving energy while maintaining a safe and comfortable environment.

  5. Difficult colonoscopy: air, carbon dioxide, or water insufflation?

    Science.gov (United States)

    Chaubal, Alisha; Pandey, Vikas; Patel, Ruchir; Poddar, Prateik; Phadke, Aniruddha; Ingle, Meghraj; Sawant, Prabha

    2018-04-01

    This study aimed to compare tolerance to air, carbon dioxide, or water insufflation in patients with anticipated difficult colonoscopy (young, thin, obese individuals, and patients with prior abdominal surgery or irradiation). Patients with body mass index (BMI) less than 18 kg/m 2 or more than 30 kg/m 2 , or who had undergone previous abdominal or pelvic surgeries were randomized to air, carbon dioxide, or water insufflation during colonoscopy. The primary endpoint was cecal intubation with mild pain (less than 5 on visual analogue scale [VAS]), without use of sedation. The primary end point was achieved in 32.7%, 43.8%, and 84.9% of cases with air, carbon dioxide and water insufflation ( P carbon dioxide, and water insufflation ( P carbon dioxide for pain tolerance. This was seen in the subgroups with BMI 30 kg/m 2 .

  6. New technology for carbon dioxide at high pressure

    International Nuclear Information System (INIS)

    Hassina, Bazaze; Raouf, Zehioua; Menial, A. H.

    2006-01-01

    Carbon dioxide has long been the nemesis of environmentalists because of its role in global warming, but under just the right conditions-namely, high pressure and high temperature its one of nature's best and most environmentally benign solvents. Decaf-coffee lovers, for instance, benefit from its ability to remove caffeine from coffee beans.During the last few years, carbon dioxide has also made inroads in the dry-cleaning industry, providing a safe cleaning alternative to the chemical perchloroethylene. But it's on the high-tech front that carbon dioxide may make its biggest impact. T here are huge opportunities. Scientists have known for more than a century that at 75 times atmospheric pressure and 31 degree centigrade, carbon dioxide goes into and odd state that chemists called s upercritical . What's interesting to industry is that supercritical carbon dioxide may be an enabling technology for going to smaller dimensions.(Author)

  7. Preparation and Performance Validation of Nano-Perovskite Type for Carbon Dioxide Reforming of Methane.

    Science.gov (United States)

    Kim, Taegyu; Park, Daeil

    2018-02-01

    This paper describes the La0.8Sr0.2NiO3 perovskite-type catalysts supported on α-Al2O3 that were prepared by polyol method and used as a catalyst for the carbon dioxide reforming of methane. The effect of the molar concentration of polyvinyl-pyrrolidone (PVP) on the reducibility, structural properties and carbon deposition was characterized by XRD, and TGA. The carbon dioxide reforming of methane on the catalyst was performed at the different concentration of PVP. At the 1 M PVP, main characteristic peaks of perovskite structure were established without impurities, thus showing the highest catalytic activity; 87.7% and 92.1% in CH4 and CO2 conversion, respectively. After the reaction, carbon deposition was 0.4-0.6%, while 6.2% on the existing Ni catalyst, indicating the perovskite-type catalyst has a superior characteristic preventing it from the carbon deposition at the carbon dioxide reforming of methane.

  8. Nickel metal with various morphologies: synthesis and performances for catalytic carbon dioxide reforming with methane.

    Science.gov (United States)

    Teabpinyok, Nopporn; Samingprai, Sutheerawat; Chareonpanich, Metta

    2012-12-01

    In this research, nickel metal of three different morphologies including nanostar, icosahedra, and microsphere structures were synthesized. It was found nanostar nickel revealed the Ni(111) crystallographic plane with particle size in the range of 150-200 nm and BET surface area of 13 m2/g. The icosahedra nickel also showed the Ni(111) crystallographic plane with larger particle size (300-400 nm) and BET surface area of 20 m2/g, whereas microsphere nickel exhibited the relatively large cluster size (approximately 3 microm) and BET surface area (114 m2/g) as a result of an aggregation of Ni(101) nanoplates. The obtained nickel catalysts were tested for the activity in carbon dioxide reforming with methane. Based on the similar specific surface area of catalysts, nanostar nickel showed the highest carbon dioxide and methane conversions due to its crystallographic structure. At 700 degrees C, nanostar nickel catalyst exhibited the highest carbon dioxide and methane conversions of 17.6 and 10.5 times higher than those of microsphere nickel catalyst, respectively.

  9. Photocatalytically active titanium dioxide nanopowders: Synthesis, photoactivity and magnetic separation

    International Nuclear Information System (INIS)

    Nikkanen, J-P; Heinonen, S; Saarivirta, E Huttunen; Honkanen, M; Levänen, E

    2013-01-01

    Two approaches were used to obtain nanocrystalline titanium dioxide (TiO 2 ) photocatalyst powders. Firstly, low-temperature synthesis method and secondly liquid flame spraying. The structural properties of the produced powders were determined with X-ray diffraction, transmission electron microscopy and nitrogen adsorption tests. The photocatalytic properties of the powders were studied with methylene blue (MB) discoloration tests. After discolorations tests, TiO 2 was coagulated with magnetite particles using FeCl 3 ·6 H 2 O at a fixed pH value. Magnetic separation of coagulated TiO 2 and magnetite was carried out by a permanent magnet. The obtained results showed that the particle size of the powders synthesized at low-temperature was very small and the specific surface area high. The phase content of the powder was also shown to depend greatly on the acidity of the synthesis solution. Powder synthesized by liquid flame spraying was mixture of anatase and rutile phases with essentially larger particle size and lower specific surface area than those of low-temperature synthesized powders. The MB discoloration test showed that photocatalytic activity depends on the phase structure as well as the specific surface area of the synthesized TiO 2 powder. The magnetic separation of TiO 2 –magnetite coagulate from solution proved to be efficient around pH:8

  10. Irradiation of TZM: Uranium dioxide fuel pin at 1700 K

    Science.gov (United States)

    Mcdonald, G. E.

    1973-01-01

    A fuel pin clad with TZM and containing solid pellets of uranium dioxide was fission heated in a static helium-cooled capsule at a maximum surface temperature of 1700 K for approximately 1000 hr and to a total burnup of 2.0 percent of the uranium-235. The results of the postirradiation examination indicated: (1) A transverse, intergranular failure of the fuel pin occurred when the fuel pin reached 2.0-percent burnup. This corresponds to 1330 kW-hr/cu cm, where the volume is the sum of the fuel, clad, and void volumes in the fuel region. (2) The maximum swelling of the fuel pin was less than 1.5 percent on the fuel-pin diameter. (3) There was no visible interaction between the TZM clad and the UO2. (4) Irradiation at 1700 K produced a course-grained structure, with an average grain diameter of 0.02 centimeter and with some of the grains extending one-half of the thickness of the clad. (5) Below approximately 1500 K, the irradiation of the clad produced a moderately fine-grained structure, with an average grain diameter of 0.004 centimeter.

  11. Design, fabrication and characterization of a two-step released silicon dioxide piezoresistive microcantilever immunosensor

    International Nuclear Information System (INIS)

    Zhou, Youzheng; Wang, Zheyao; Wang, Chaonan; Ruan, Wenzhou; Liu, Litian

    2009-01-01

    This paper presents the design, fabrication and characterization of a silicon dioxide piezoresistive microcantilever immunosensor fabricated on silicon-on-insulator (SOI) wafers. The microcantilever consists of two strips of single crystalline silicon piezoresistors sandwiched in between two silicon dioxide layers. A theoretical model for the laminated microcantilever with a discontinuous layer is deduced using classic laminated beam theory. A two-step release method combining anisotropic and isotropic etching is developed to suspend the microcantilever, and the fabrication results show an excellent yield. The residual stress-induced free bending of the microcantilever and the stress caused by self-heating of the piezoresistors are discussed. The microcantilever sensor is characterized as an immunosensor using specific binding of antigen and antibody. These methods and some conclusions are also applicable to the development of other piezoresistive sensors that use laminated structures

  12. Social Roots of Global Environmental Change: A World-Systems Analysis of Carbon Dioxide Emissions

    Directory of Open Access Journals (Sweden)

    J. Timmons Roberts

    2015-08-01

    Full Text Available Carbon dioxide is understood to be the most important greenhouse gas believed to be altering the global climate. This article applies world-system theory to environmental damage. An analysis of 154 countries examines the contribution of both position in the world economy and internal class and political forces in determining a nation's CO, intensity. CO, intensity is defined here as the amount of carbon dioxide released per unit of economic output. An inverted U distribution of CO, intensity across the range of countries in the global stratification system is identified and discussed. Ordinary Least Squares regression suggests that the least efficient consumers of fossil fuels are some countries within the semi-periphery and upper periphery, spe-cifically those nations which are high exporters, those highly in debt, nations with higher military spending, and those with a repressive social structure.

  13. Investigation of plasma dynamics during the growth of amorphous titanium dioxide thin films

    Science.gov (United States)

    Kim, Jin-Soo; Jee, Hyeok; Yu, Young-Hun; Seo, Hye-Won

    2018-06-01

    We have grown amorphous titanium dioxide thin films by reactive DC sputtering method using a different argon/oxygen partial pressure at a room temperature. The plasma dynamics of the process, reactive and sputtered gas particles was investigated via optical emission spectroscopy. We then studied the correlations between the plasma states and the structural/optical properties of the films. The growth rate and morphology of the titanium dioxide thin films turned out to be contingent with the population and the energy profile of Ar, O, and TiO plasma. In particular, the films grown under energetic TiO plasma have shown a direct band-to-band transition with an optical energy band gap up to ∼4.2 eV.

  14. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).

    Science.gov (United States)

    Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

    2010-01-15

    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. Copyright 2009 Elsevier B.V. All rights reserved.

  15. Pulsed TEA CO2 Laser Irradiation of Titanium in Nitrogen and Carbon Dioxide Gases

    Science.gov (United States)

    Ciganovic, J.; Matavulj, P.; Trtica, M.; Stasic, J.; Savovic, J.; Zivkovic, S.; Momcilovic, M.

    2017-12-01

    Surface changes created by interaction of transversely excited atmospheric carbon dioxide (TEA CO2) laser with titanium target/implant in nitrogen and carbon dioxide gas were studied. TEA CO2 laser operated at 10.6 μm, pulse length of 100 ns and fluence of ˜17 J/cm2 which was sufficient for inducing surface modifications. Induced changes depend on the gas used. In both gases the grain structure was produced (central irradiated zone) but its forms were diverse, (N2: irregular shape; CO2: hill-like forms). Hydrodynamic features at peripheral zone, like resolidified droplets, were recorded only in CO2 gas. Elemental analysis of the titanium target surface indicated that under a nitrogen atmosphere surface nitridation occurred. In addition, irradiation in both gases was followed by appearance of plasma in front of the target. The existence of plasma indicates relatively high temperatures created above the target surface offering a sterilizing effect.

  16. Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China

    NARCIS (Netherlands)

    Seow, Wei Jie; Downward, George S; Wei, Hu; Rothman, Nathaniel; Reiss, Boris; Xu, Jun; Bassig, Bryan A; Li, Jihua; He, Jun; Hosgood, H Dean; Wu, Guoping; Chapman, Robert S; Tian, Linwei; Wei, Fusheng; Caporaso, Neil E; Vermeulen, Roel; Lan, Qing

    2016-01-01

    The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation

  17. Dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate-hydrogen peroxide

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Pathak, P.N.; Mohapatra, P.K.; Manchanda, V.K.

    2009-01-01

    Direct dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate (TBP) has been attempted. The effects of TBP concentration and pressure on the extraction of uranium have been studied. Addition of hydrogen peroxide in the modifier enhances the dissolution/extraction of uranium. (author)

  18. Photobiological hydrogen production and carbon dioxide sequestration

    Science.gov (United States)

    Berberoglu, Halil

    Photobiological hydrogen production is an alternative to thermochemical and electrolytic technologies with the advantage of carbon dioxide sequestration. However, it suffers from low solar to hydrogen energy conversion efficiency due to limited light transfer, mass transfer, and nutrient medium composition. The present study aims at addressing these limitations and can be divided in three parts: (1) experimental measurements of the radiation characteristics of hydrogen producing and carbon dioxide consuming microorganisms, (2) solar radiation transfer modeling and simulation in photobioreactors, and (3) parametric experiments of photobiological hydrogen production and carbon dioxide sequestration. First, solar radiation transfer in photobioreactors containing microorganisms and bubbles was modeled using the radiative transport equation (RTE) and solved using the modified method of characteristics. The study concluded that Beer-Lambert's law gives inaccurate results and anisotropic scattering must be accounted for to predict the local irradiance inside a photobioreactor. The need for accurate measurement of the complete set of radiation characteristics of microorganisms was established. Then, experimental setup and analysis methods for measuring the complete set of radiation characteristics of microorganisms have been developed and successfully validated experimentally. A database of the radiation characteristics of representative microorganisms have been created including the cyanobacteria Anabaena variabilis, the purple non-sulfur bacteria Rhodobacter sphaeroides and the green algae Chlamydomonas reinhardtii along with its three genetically engineered strains. This enabled, for the first time, quantitative assessment of the effect of genetic engineering on the radiation characteristics of microorganisms. In addition, a parametric experimental study has been performed to model the growth, CO2 consumption, and H 2 production of Anabaena variabilis as functions of

  19. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  20. Impact of silica dioxide nanoparticles on the morphology of internal organs in rats by oral supplementation

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2016-12-01

    Full Text Available The object of the study was amorphous silica dioxide (SiO 2 , which is widely used as a food additive (E551, a subsidiary component in pharmaceutical preparations, perfumery and cosmetic products etc. In the specification of JECFA silica dioxide does not have information about the size of its particles, which allows the use of fine amorphous SiO 2 , obtained by gas phase hydrolysis of tetrachlorosilane as a food additive. This material, known as the "Aerosil", is characterized by the size of the specific surface area of 300–380 m 2 /g and the size of its relatively weakly agglomerated particles of 6–30 nm, i.e., it is a nanomaterial. In the biological model the morphological changes in organs and tissue systems on oral supplementation of nanoscale particles of silica dioxide were studied. Wistar male rats were given nanosized silica dioxide with specific surface area of 300 m 2 /g and primary nanoparticle size on the basis of data of electrical, atomic-powered microscopy, and dynamic light scattering in the range of 20–60 nm during 92 days. Light microscopic morphological examination of organs of rats showed a relatively mild inflammation in the structure of parenchymal organs (liver, kidney, not showing a certain dose-dependent nanoparticles. The most pronounced changes were in ileum morphology, consisting of a massive lymph macrophage and eosinophil infiltration of villi, without any apparent violation of their epithelial layer structure, which indirectly indicates the absence of violations of the barrier function of the intestinal epithelium. At the maximum dose of 100 mg/kg bw, the increased immune response was the most significant in the wall of the ileum. The results indicate the potential risks to human health when using SiO 2 having a specific surface area of 300 m 2 /g or higher in the composition of food products as a food additive.

  1. Systematic framework for carbon dioxide capture and utilization processes to reduce the global carbon dioxide emissions

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Plaza, Cristina Calvera; Gani, Rafiqul

    information-data on various carbon dioxide emission sources and available capture-utilization technologies; the model and solution libraries [2]; and the generic 3-stage approach for determining more sustainable solutions [3] through superstructure (processing networks) based optimization – adopted for global...... need to provide, amongst other options: useful data from in-house databases on carbon dioxide emission sources; mathematical models from a library of process-property models; numerical solvers from library of implemented solvers; and, work-flows and data-flows for different benefit scenarios...... to be investigated. It is useful to start by developing a prototype framework and then augmenting its application range by increasing the contents of its databases, libraries and work-flows and data-flows. The objective is to present such a prototype framework with its implemented database containing collected...

  2. Sulfur dioxide: foe or friend for life?

    Science.gov (United States)

    Wang, Xin-Bao; Cui, Hong; Liu, Xiaohong; Du, Jun-Bao

    2017-12-01

    Sulfur dioxide (SO₂) is a toxic gas and air pollutant. The toxic effects of SO₂ have been extensively studied. Oxidative damage due to SO₂ can occur in multiple organs. Inhaled SO₂ can also cause chromosomal aberrations, DNA damage and gene mutations in mammals. However, SO₂ can also be generated from the sulfur-containing amino acid, L-cysteine. Recent studies have shown that SO₂ has a vasorelaxant effect, and ameliorates pulmonary hypertension and vascular remodeling. SO₂ can also reduce lung injury and myocardial injury in rats. In addition, SO₂ reduces myocardial ischemia-reperfusion injury and atherosclerotic lesions. Therefore, SO₂ exerts both detrimental and protective effects in mammals. Is SO₂ a foe or friend for life?.

  3. Miniaturized remission sensor for carbon dioxide detection

    International Nuclear Information System (INIS)

    Martan, T; Will, M

    2010-01-01

    Recently, optical sensors for detection of carbon dioxide (CO 2 ) have been explored for variety of applications in chemistry, industry, and medicine. This paper deals with the development of a planar optical remission sensor employing a dye immobilized in a polymer layer designed for gaseous CO 2 detection. The principle of CO 2 detection was based on colour changes of Tetraethylammonium Cresol red immobilized in a special composed polymer layer that was irradiated by LED diodes. Absorption properties of the dye were changed due to its chemical reaction with CO 2 and corresponding colour changes were detected by PIN diodes. These changes were analyzed by using a PC-controlled board connected by USB. The sensitivity, response time, and the detection limit of the remission sensor were characterized.

  4. Carbon dioxide: Global warning for nephrologists.

    Science.gov (United States)

    Marano, Marco; D'Amato, Anna; Cantone, Alessandra

    2016-09-06

    The large prevalence of respiratory acid-base disorders overlapping metabolic acidosis in hemodialysis population should prompt nephrologists to deal with the partial pressure of carbon dioxide (pCO2) complying with the reduced bicarbonate concentration. What the most suitable formula to compute pCO2 is reviewed. Then, the neglected issue of CO2 content in the dialysis fluid is under the spotlight. In fact, a considerable amount of CO2 comes to patients' bloodstream every hemodialysis treatment and "acidosis by dialysate" may occur if lungs do not properly clear away this burden of CO2. Moreover, vascular access recirculation may be easy diagnosed by detecting CO2 in the arterial line of extracorporeal circuit if CO2-enriched blood from the filter reenters arterial needle.

  5. Carbon dioxide neutral, integrated biofuel facility

    Energy Technology Data Exchange (ETDEWEB)

    Powell, E.E.; Hill, G.A. [Department of Chemical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan, S7N 5A9 (Canada)

    2010-12-15

    Algae are efficient biocatalysts for both capture and conversion of carbon dioxide in the environment. In earlier work, we have optimized the ability of Chlorella vulgaris to rapidly capture CO{sub 2} from man-made emission sources by varying environmental growth conditions and bioreactor design. Here we demonstrate that a coupled biodiesel-bioethanol facility, using yeast to produce ethanol and photosynthetic algae to produce biodiesel, can result in an integrated, economical, large-scale process for biofuel production. Each bioreactor acts as an electrode for a coupled complete microbial fuel cell system; the integrated cultures produce electricity that is consumed as an energy source within the process. Finally, both the produced yeast and spent algae biomass can be used as added value byproducts in the feed or food industries. Using cost and revenue estimations, an IRR of up to 25% is calculated using a 5 year project lifespan. (author)

  6. Fluorination reaction uranium dioxide by fluorine

    International Nuclear Information System (INIS)

    Ogata, Shinji; Homma, Shunji; Koga, Jiro; Matsumoto, Shiro; Sasahira, Akira; Kawamura, Fumio

    2004-01-01

    Kinetics of the fluorination reaction of uranium dioxide is studied using un-reacted core model with shrinking particles. The model includes the film mass transfer of fluorine gas and its diffusion in the particle. The rate constants of the model are determined by fitting the experimental data for 370-450degC. The model successfully represents the fluorination in this temperature range. The rate control step is identified by examining the rate constants of the model for 300-1,800degC. For temperature range up to 900degC, the fluorination reaction is rate controlling. For over 900degC, both mechanisms of the mass transfer of fluorine and the fluorination reaction control the rate of the fluorination. With further increase of the temperature, however, the fluorination reaction becomes so fast that the mass transfer of fluorine eventually controls the rate of the fluorination. (author)

  7. Carbon dioxide removal with inorganic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, R.R.; Fain, D.E. [Oak Ridge National Laboratory, TN (United States)

    1993-12-31

    The increasing concentrations of greenhouse gases, particularly carbon dioxide, in the atmosphere has sparked a great deal of interest in the removal of CO{sub 2} from flue gases of fossil fueled plants. Presently, several techniques for the removal of CO{sub 2} are considered to have potential, but are lacking in practicality. For example, amine scrubbing of flue gas streams is potential, but are lacking in practically. For example, amine scrubbing of flue gas streams is effective in removing CO{sub 2}, but costs are high; efficiency suffers; and other acid gases must be removed prior to amine stripping. Membrane systems for CO{sub 2} removal are held in high regard, and inorganic, particularly ceramic, membranes offer the potential for high temperature, thus energy saving, removal.

  8. Heat transfer coeffcient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1997-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The pipe is heated by condensing R22 outside the pipe. The heat input is supplied by an electrical heater wich evaporates the R22. With the heat flux assumed constant over...... the whole surface and with measured temperature difference between the inner surface and the evaporation temperature a mean heat transfer coefficient is calculated. The calculated heat transfer coefficient has been compared with the Chart Correlation of Shah. The Chart Correlation predicts too low heat...... transfer coefficient but the ratio between the measured and the calculated heat transfer coefficient is nearly constant and equal 1.9. With this factor the correlation predicts the measured data within 14% (RMS). The pressure drop is of the same order as the measuring uncertainty and the pressure drop has...

  9. Dissolution experiments of unirradiated uranium dioxide pellets

    International Nuclear Information System (INIS)

    Ollila, K.

    1985-01-01

    The purpose of this study was to measure the dissolution rate of uranium from unirradiated uranium dioxide pellets in deionized water and natural groundwater. Moreover, the solubility limit of uranium in natural groundwater was measured. Two different temperatures, 25 and 60 deg C were used. The low oxygen content of deep groundwater was simulated. The dissolution rate of uranium varied from 10 -7 to 10 -8 g cm -2 d -1 . The rate in reionized water was one order of magnitude lower than in groundwater. No great difference was observed between the natural groundwaters with different composition. Temperature seems to have effect on the dissolution rate. The solubility limit of uranium in natural groundwater in reducing conditions, at 25 deg C, varied from 20 to 600 μg/l and in oxidizing conditions, at 60 deg C, from 4 to 17 mg/l

  10. Carbon Dioxide in Arable Soil Profiles

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Plauborg, Finn; Heckrath, Goswin Johann

    2014-01-01

    on the comparability of results obtained using different methods is limited. We therefore aimed to compare the dynamics in soil CO2 concentrations obtained from an automated system (GMP343 sensors) to those from a manually operated measurement system (i.e., soil gas sampled using stainless steel needles and rods......Carbon dioxide (CO2) concentrations in arable soil profiles are influenced by autotrophic and heterotrophic respiration as well as soil physical properties that regulate gas transport. Whereas different methods have been used to assess dynamics of soil CO2 concentrations, our understanding...... systems. Within the measurement range for the GMP343 sensors (0-20,000 ppm), mean results from the two systems were similar within the plough layer at the upslope (P = 0.060) and footslope (P = 0.139) position, and also below the plough layer at the upslope position (P = 0.795). However, results from...

  11. Carbon dioxide emissions from biochar in soil

    DEFF Research Database (Denmark)

    Bruun, Sander; Clauson-Kaas, Anne Sofie Kjærulff; Bobuľská, L.

    2014-01-01

    The stability of biochar in soil is of importance if it is to be used for carbon sequestration and long-term improvement of soil properties. It is well known that a significant fraction of biochar is highly stable in soil, but carbon dioxide (CO2) is also released immediately after application....... This study investigated the nature of the early release of CO2 and the degree to which stabilizing mechanisms protect biochar from microbial attack. Incubations of 14C-labelled biochar produced at different temperatures were performed in soils with different clay contents and in sterilized and non......-sterilized soils. It emerged that carbonate may be concentrated or form during or after biochar production, resulting in significant carbonate contents. If CO2 released from carbonates in short-term experiments is misinterpreted as mineralization of biochar, the impact of this process may be significantly over...

  12. Precipitated nanosized titanium dioxide for electrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kirillov, S.A. [Joint Department of Electrochemical Energy Systems, 38A Vernadsky Ave., 03142 Kyiv (Ukraine); Institute for Sorption and Problems of Endoecology, 13 Gen. Naumov St., 03164 Kyiv (Ukraine); Lisnycha, T.V. [Institute for Sorption and Problems of Endoecology, 13 Gen. Naumov St., 03164 Kyiv (Ukraine); Chernukhin, S.I. [Joint Department of Electrochemical Energy Systems, 38A Vernadsky Ave., 03142 Kyiv (Ukraine)

    2011-02-15

    Two types of titanium dioxide samples precipitated from aqueous solutions of titanium tetrachloride are investigated. Crystalline materials are obtained by means of neutralization of TiCl{sub 4} with the solution of an alkali metal hydroxide. The change of the order of mixing leads to amorphous materials. The evolution of the samples upon the thermal treatment is characterized using XRD, SEM, TEM and porosity studies. The application of crystalline TiO{sub 2} as an electrode material in lithium-ion 2016 sample cells enable one to yield specific currents up to 3350 mA g{sup -1}. On the other hand, the thermal treatment of initially amorphous materials does not lead to complete crystallization, and the presence of amorphous TiO{sub 2} is well seen as the so-called capacity behavior of cyclic voltammetry curves. (author)

  13. Uranium dioxide calcining apparatus and method

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 0 C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving, cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means

  14. Preparation and integration of nanostructured titanium dioxide

    KAUST Repository

    Zeng, Hua Chun

    2011-10-01

    Titanium dioxide (TiO2) is a chemically stable nontoxic transition-metal oxide associated with a wide range of existing chemical engineering processes. In this short review, recent research endeavors in preparation and integration of nanostructured TiO2 materials system will be featured and discussed for their potential new applications. Because material development always plays pivotal roles in the progress of a particular engineering discipline, the reviewed subjects will provide useful information to stimulate nanoscale research of chemical engineering, linking established fundamentals with practical applications. Some critical issues and challenges regarding further development of this important functional material for nanotechnology will also be addressed. © 2011 Elsevier Ltd. All rights reserved.

  15. Hydrodynamic Controls on Carbon Dioxide Efflux from Inland Waters

    Science.gov (United States)

    Long, H. E.; Waldron, S.; Hoey, T.; Newton, J.; Quemin, S.

    2013-12-01

    Intensive research has been undertaken on carbon dioxide efflux from lakes, estuaries and oceans, but much less attention has been given to rivers and streams, especially lower order streams. River systems are often over-saturated with carbon dioxide and so tend to act as sources of carbon dioxide to the atmosphere. It has been thought that rivers act as pipes carrying this terrestrial carbon to the oceans. However, recent studies have shown that a significant amount of the carbon is reprocessed within the system in a series of transformations and losses. Fluvial evasion of carbon dioxide is now recognised to be a significant component of carbon cycles, however the factors controlling carbon dioxide efflux and its magnitude remain poorly understood and quantified. This research aims to quantify, and better understand the controls on, freshwater carbon dioxide evasion. Data are presented here from field measurements that commenced in Sept 2013 in two contrasting Scottish rivers: the River Kelvin which has a large (335 km.sq) part-urban catchment with predominantly non-peat soils and Drumtee Water, a small (9.6 km.sq) rural catchment of peat soils and agricultural land. Using a floating chamber with the headspace connected to an infrared gas analyser to measure changes in carbon dioxide concentration, efflux rates from 0.22 - 47.4 μmol CO2/m.sq/sec were measured, these close to the middle of the range of previously reported values. At one site on the River Kelvin in May 2013 an influx of -0.61 - -3.53 μmol CO2/m.sq/sec was recorded. Whereas previous research finds carbon dioxide efflux to increase with decreasing river size and a more organic-rich soil catchment, here the controls on carbon dioxide evasion are similar across the contrasting catchments. Carbon dioxide evasion shows seasonality, with maximum fluxes in the summer months being up to twice as high as the winter maxima. Linear regression demonstrates that evasion increases with increased flow velocity

  16. Coiled tubing drilling with supercritical carbon dioxide

    Science.gov (United States)

    Kolle , Jack J.

    2002-01-01

    A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO.sub.2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO.sub.2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC--CO.sub.2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC--CO.sub.2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC--CO.sub.2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC--CO.sub.2 much more effective than water jet erosion. SC--CO.sub.2 jets can be used to assist mechanical drilling, for erosion drilling, or for scale removal. A choke manifold at the well head or mud cap drilling equipment can be used to control the pressure within the borehole, to ensure that the temperature and pressure conditions necessary for CO.sub.2 to exist as either a supercritical fluid or a dense gas occur at the drill site. Spent CO.sub.2 can be vented to the atmosphere, collected for reuse, or directed into the formation to aid in the recovery of petroleum.

  17. Intraosseous Venography with Carbon Dioxide in Percutaneous Vertebroplasty: Carbon Dioxide Retention in Renal Veins

    International Nuclear Information System (INIS)

    Komemushi, Atsushi; Tanigawa, Noboru; Kariya, Shuji; Kojima, Hiroyuki; Shomura, Yuzo; Tokuda, Takanori; Nomura, Motoo; Terada, Jiro; Kamata, Minoru; Sawada, Satoshi

    2008-01-01

    The objective of the present study was to determine the frequency of gas retention in the renal vein following carbon dioxide intraosseous venography in the prone position and, while citing references, to examine its onset mechanisms. All percutaneous vertebroplasties performed at our hospital from January to December 2005 were registered and retrospectively analyzed. Of 43 registered procedures treating 79 vertebrae, 28 procedures treating 54 vertebrae were analyzed. Vertebral intraosseous venography was performed using carbon dioxide as a contrast agent in all percutaneous vertebroplasty procedures. In preoperative and postoperative vertebral CT, gas retention in the renal vein and other areas was assessed. Preoperative CT did not show gas retention (0/28 procedures; 0%). Postoperative CT confirmed gas retention in the renal vein in 10 of the 28 procedures (35.7%). Gas retention was seen in the right renal vein in 8 procedures (28.6%), in the left renal vein in 5 procedures (17.9%), in the left and right renal veins in 3 procedures (10.7%), in vertebrae in 22 procedures (78.6%), in the soft tissue around vertebrae in 14 procedures (50.0%), in the spinal canal in 12 procedures (42.9%), and in the subcutaneous tissue in 5 procedures (17.9%). In conclusion, in our study, carbon dioxide gas injected into the vertebra frequently reached and remained in the renal vein.

  18. Computational Recreation of Carbon Dioxide Hydrates at Habitable Planetary Conditions

    Science.gov (United States)

    Recio, J. M.; Izquierdo-Ruiz, F.; Prieto-Ballesteros, O.

    2017-12-01

    Gas clathrate hydrates are proposed as constituents of the icy moons of the giant planets in the Solar System [1]. Carbon dioxide has been detected on the surface of the moons of Jupiter, supposedly originated by internal degasification. In Ganymede, an aqueous ocean is proposed to exist under a thick ice crust in coexistence with several forms of ice, with pressure reaching up to 1.3 GPa [2]. Due to the limited available data on these systems under these conditions, we propose a combination of computational and experimental studies to describe microscopically and macroscopically the structural and chemical behavior of CO2@H2O polymorphs. This will allow us to understand how their presence affects the geophysical structure and activity and their impact on the habitability of the icy moon. A transition from the sI cubic structure to a high pressure phase at around 0.7 GPa has been found for CO2@H2O. In spite of different attempts to characterize the new structure, a definite answer has not been provided yet. A MH-III Filled Ice Structure type was proposed after neutron diffraction experiments in contrast with an alternative structure similar to the hexagonal C0 type for H2 hydrates [3]. It has an estimated hydration level ratio up to 2H2O:1CO2 and 6 water molecules per unit cell. In the figure below, our optimized unit cell based on this hexagonal C0 structure is displayed. Ab initio calculations using the XDM approximation to include van der Waals effects are performed in our search for the pressure evolution of the equilibrium geometries of the C0-CO2@H2O phase and those of a close related structure to this one called Ih-C0, with 8 water molecules per unit cell. We obtain occupation energies at different hydration ratios, densities, equations of state parameters, and stability energies with respect to decomposition. Raman and IR frequencies are also computed in the 0-2 GPa range. High pressure experiments are also being done in a newly designed chamber able to

  19. Modeling and calculation of open carbon dioxide refrigeration system

    International Nuclear Information System (INIS)

    Cai, Yufei; Zhu, Chunling; Jiang, Yanlong; Shi, Hong

    2015-01-01

    Highlights: • A model of open refrigeration system is developed. • The state of CO 2 has great effect on Refrigeration capacity loss by heat transfer. • Refrigeration capacity loss by remaining CO 2 has little relation to the state of CO 2 . • Calculation results are in agreement with the test results. - Abstract: Based on the analysis of the properties of carbon dioxide, an open carbon dioxide refrigeration system is proposed, which is responsible for the situation without external electricity unit. A model of open refrigeration system is developed, and the relationship between the storage environment of carbon dioxide and refrigeration capacity is conducted. Meanwhile, a test platform is developed to simulation the performance of the open carbon dioxide refrigeration system. By comparing the theoretical calculations and the experimental results, several conclusions are obtained as follows: refrigeration capacity loss by heat transfer in supercritical state is much more than that in two-phase region and the refrigeration capacity loss by remaining carbon dioxide has little relation to the state of carbon dioxide. The results will be helpful to the use of open carbon dioxide refrigeration

  20. Investigation of transformation of uranium hexafluoride into dioxide

    International Nuclear Information System (INIS)

    Galkin, N.P.; Veryatin, U.D.; Yakhonin, I.F.; Logunov, A.F.; Dymkov, Yu.M.

    1982-01-01

    The process of transformation of uranium hexafluoride into dioxide using the method of pyrohydrolysis by steam-hydrogen mixture in a boiling layer using uranium dioxide granules applicable for production of fuel elements is considered. Technological parameters and equipment of the process are described, intermediate stages and process products are considered. Physicochemical and physicomechanical properties of the obtained uranium dioxide granules are given. The results of metallographical investigations into solid products of pyrohydrolysis in phase transformations at certain stages of the process as well as test on vibration packing of the obtained granules in fuel cans are presented

  1. Carbon dioxide fluid-flow modeling and injectivity calculations

    Science.gov (United States)

    Burke, Lauri

    2011-01-01

    At present, the literature lacks a geologic-based assessment methodology for numerically estimating injectivity, lateral migration, and subsequent long-term containment of supercritical carbon dioxide that has undergone geologic sequestration into subsurface formations. This study provides a method for and quantification of first-order approximations for the time scale of supercritical carbon dioxide lateral migration over a one-kilometer distance through a representative volume of rock. These calculations provide a quantified foundation for estimating injectivity and geologic storage of carbon dioxide.

  2. Carbon dioxide and nisin act synergistically on Listeria monocytogenes

    DEFF Research Database (Denmark)

    Nilsson, Lilian; Chen, Y.H.; Chikindas, M.L.

    2000-01-01

    This paper examines the synergistic action of carbon dioxide and nisin on Listeria monocytogenes Scott A wild-type and nisin-resistant (Nis(r)) cells grown in broth at 4 degrees C. Carbon dioxide extended the lag phase and decreased the specific growth rate of both strains, but to a greater degree...... for cultures in CO2. This synergism between nisin and CO2 was examined mechanistically by following the leakage of carboxyfluorescein (CF) from listerial liposomes. Carbon dioxide enhanced nisin-induced CF leakage, indicating that the synergistic action of CO2 and nisin occurs at the cytoplasmic membrane...

  3. Terpolymerization of ethylene, sulfur dioxide and carbon monoxide

    Science.gov (United States)

    Johnson, R.; Steinberg, M.

    This invention relates to high molecular weight terpolymer of ethylene, sulfur dioxide and carbon monoxide stable to 280/sup 0/C and containing as little as 36 mo1% ethylene and about 41 to 51 mo1% sulfur dioxide, and to the method of producing said terpolymer by irradiation of a liquid and gaseous mixture of ethylene, sulfur dioxide and carbon monoxide by means of Co-60 gamma rays or an electron beam, at a temperature of about 10 to 50/sup 0/C, and at a pressure of about 140 to 680 atmospheres, to initiate polymerization.

  4. Stratospheric nitrogen dioxide in the vicinity of Soufriere, St. Vincent

    Science.gov (United States)

    Romick, G. J.; Murcray, D. G.; Williams, W. J.

    1982-01-01

    In April 1979, measurements of nitrogen dioxide in the upper atmosphere were made near Soufriere Volcano by twilight optical-absorption techniques. The derived value of 5 x 10 to the 15th molecules per square centimeter column implies an enhancement of 25 percent over earlier abundances measured in the same latitudinal regions. This enhancement may represent the normal stratospheric variability of nitrogen dioxide in the equatorial region, but in any case may be considered an upper limit to the volcano's effect on the total nitrogen dioxide abundance.

  5. Behaviour of uranium dioxide in liquid nitrogen tetraoxide

    International Nuclear Information System (INIS)

    Kobets, L.V.; Klavsut', G.N.; Dolgov, V.M.

    1983-01-01

    Interaction kinetics of uranium dioxide with liquid nitrogen tetroxide at 25-150 deg C has been studied. It is shown that in the temperature range studied NO[UO 2 (NO 3 ) 3 ] is the final product of the reaction. With the increase of specific surface of uranium dioxide and with the temperature increase the degree of oxide transformation increases. Uranium dioxide-liquid N 2 O 4 interaction proceeds in the diffusion region. Seeming activation energies and rate constants of the mentioned processes are calculated. Effect of nitrogen trioxide additions on transformation kinetics is considered

  6. Production and emission of methane and carbon dioxide by ruminants

    International Nuclear Information System (INIS)

    Chouinard, Y.

    2003-01-01

    Animal digestion is responsible for the production of both carbon dioxide and methane, while breathing produces only carbon dioxide. The author described the digestion mechanism of ruminants, explaining that they produce higher levels of methane and carbon dioxide than other animals. Fermentation stoichiometry of ruminants was also discussed along with the influence that diet has on methane production. It was noted that methane production can be decreased by increasing animal productivity, or by using ionophore antibiotics and long chain fatty acids. Test results from each of these methods have revealed side effects and none appears to be applicable for the time being. 10 refs., 1 tab., 1 fig

  7. Interaction of titanium and vanadium with carbon dioxide under heating

    International Nuclear Information System (INIS)

    Vlasyuk, R.Z.; Kurovskij, V.Ya.; Lyapunov, V.P.; Radomysel'skij, I.D.

    1986-01-01

    The methods of gravitmetric and X-ray phase analysis as well as analysis of composition of gases in the heating chamber have been used to investigate the mechanism of titanium and vanadium interaction with carbon dioxide in the 300-1000 deg C temperature range. The analogy of mechanisms of the interaction of titanium and vanadium with carbon dioxide in oxides production on the metal surface with subsequent carbidizing treatment at temperatures above 800 deg C is shown. Temperature limits of material operation on the base of titanium or vanadium in carbon dioxide must not exceed 400 or 600 deg C, respectively

  8. Degradation of sulfamethoxazole using ozone and chlorine dioxide - Compound-specific stable isotope analysis, transformation product analysis and mechanistic aspects.

    Science.gov (United States)

    Willach, Sarah; Lutze, Holger V; Eckey, Kevin; Löppenberg, Katja; Lüling, Michelle; Terhalle, Jens; Wolbert, Jens-Benjamin; Jochmann, Maik A; Karst, Uwe; Schmidt, Torsten C

    2017-10-01

    The sulfonamide antibiotic sulfamethoxazole (SMX) is a widely detected micropollutant in surface and groundwaters. Oxidative treatment with e.g. ozone or chlorine dioxide is regularly applied for disinfection purposes at the same time exhibiting a high potential for removal of micropollutants. Especially for nitrogen containing compounds such as SMX, the related reaction mechanisms are largely unknown. In this study, we systematically investigated reaction stoichiometry, product formation and reaction mechanisms in reactions of SMX with ozone and chlorine dioxide. To this end, the neutral and anionic SMX species, which may occur at typical pH-values of water treatment were studied. Two moles of chlorine dioxide and approximately three moles of ozone were consumed per mole SMX degraded. Oxidation of SMX with ozone and chlorine dioxide leads in both cases to six major transformation products (TPs) as revealed by high-resolution mass spectrometry (HRMS). Tentatively formulated TP structures from other studies could partly be confirmed by compound-specific stable isotope analysis (CSIA). However, for one TP, a hydroxylated SMX, it was not possible by HRMS alone to identify whether hydroxylation occurred at the aromatic ring, as suggested in literature before, or at the anilinic nitrogen. By means of CSIA and an analytical standard it was possible to identify sulfamethoxazole hydroxylamine unequivocally as one of the TPs of the reaction of SMX with ozone as well as with chlorine dioxide. H-abstraction and electron transfer at the anilinic nitrogen are suggested as likely initial reactions of ozone and chlorine dioxide, respectively, leading to its formation. Oxidation of anionic SMX with ozone did not show any significant isotopic fractionation whereas the other reactions studied resulted in a significant carbon isotope fractionation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Achievement report of projects in fiscal 2000 for measures on technologies to fix and utilize effectively carbon dioxide. Development of program system technologies to fix and utilize effectively carbon dioxide - researches on key technologies (Developing technology to fix carbon dioxide electrochemically); 2000 nendo program hoshiki nisanka tanso koteika yuko riyo gijutsu kaihatsu (kiban gijutsu kenkyu) seika hokokusho (kokaiyo). Nisanka tanso no denki kagakuteki koteika gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    With an objective to prevent global warming, research and development has been made on a carbon dioxide fixation technology using electrochemical means. This paper summarizes the achievements in fiscal 2000. In the research of a technology to return carbon dioxide to hydrocarbon such as methane electrochemically utilizing the high concentration carbon dioxide-methanol system, basic studies were performed on electrolytic reduction of CO2 using a methanol solvent system, and experimental studies were executed on high-speed reduction of carbon dioxide using gas diffusion electrodes. In the basic property experiment on diamond electrodes, high carbon dioxide reduction activity was obtained by having copper carried in the diamond electrode. In the CO2 electrolytic reduction experiment on three-phase interface using a copper net electrode, CO, ethylene, and methane were produced, while the electrode has retained the activity for an extended period of time, and the CO2 conversion rate reached about 66%. In structuring an electrochemical carbon dioxide fixation system, specifications for the CO2 electrolytic reduction equipment were determined, design, manufacturing, and electrode materials were selected, supporting electrolytes were discussed, and the entire system flow and liquid resistance were discussed. (NEDO)

  10. Copolymerisation of Propylene Oxide and Carbon Dioxide by Dinuclear Cobalt Porphyrins

    KAUST Repository

    Anderson, Carly E.

    2013-09-18

    Two dinuclear cobalt porphyrins comprising different structural tethering motifs at the porphyrin periphery were synthesised, along with a representative mononuclear cobalt porphyrin, and their catalytic activities tested towards carbon dioxide-propylene oxide copolymerisation in the presence of bis(triphenylphosphoranyl)ammonium chloride cocatalyst. The catalytic activities of the mononuclear and the bis-para-tethered dinuclear cobalt porphyrin with selective formation of poly(propylene carbonate) are largely comparable, showing no benefit of dinuclearity in contrast to the case of cobalt salen complexes and suggesting that polymer growth proceeds exclusively from one metal centre. The alternative bis-ortho-tethered porphyrin demonstrated considerably reduced activity, with dominant formation of cyclic propylene carbonate, as a result of hindered substrate approach at the metal centre. Time-resolved UV/Vis spectroscopic studies suggested a general intolerance of the cobalt(III) porphyrin catalysts towards the copolymerisation conditions in the absence of carbon dioxide pressure, leading to catalytically inactive cobalt(II) species. In the presence of carbon dioxide, the bis-ortho-tethered catalyst showed the fastest deactivation, which is related to an unfavourable steric arrangement of the linker fragment, as was also confirmed by NMR spectroscopic measurements. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Copolymerisation of Propylene Oxide and Carbon Dioxide by Dinuclear Cobalt Porphyrins

    KAUST Repository

    Anderson, Carly E.; Vagin, Sergei I.; Hammann, Markus; Zimmermann, Leander; Rieger, Bernhard

    2013-01-01

    Two dinuclear cobalt porphyrins comprising different structural tethering motifs at the porphyrin periphery were synthesised, along with a representative mononuclear cobalt porphyrin, and their catalytic activities tested towards carbon dioxide-propylene oxide copolymerisation in the presence of bis(triphenylphosphoranyl)ammonium chloride cocatalyst. The catalytic activities of the mononuclear and the bis-para-tethered dinuclear cobalt porphyrin with selective formation of poly(propylene carbonate) are largely comparable, showing no benefit of dinuclearity in contrast to the case of cobalt salen complexes and suggesting that polymer growth proceeds exclusively from one metal centre. The alternative bis-ortho-tethered porphyrin demonstrated considerably reduced activity, with dominant formation of cyclic propylene carbonate, as a result of hindered substrate approach at the metal centre. Time-resolved UV/Vis spectroscopic studies suggested a general intolerance of the cobalt(III) porphyrin catalysts towards the copolymerisation conditions in the absence of carbon dioxide pressure, leading to catalytically inactive cobalt(II) species. In the presence of carbon dioxide, the bis-ortho-tethered catalyst showed the fastest deactivation, which is related to an unfavourable steric arrangement of the linker fragment, as was also confirmed by NMR spectroscopic measurements. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of additives on enhanced sintering and grain growth in uranium dioxide

    International Nuclear Information System (INIS)

    Bourgeois, L.

    1992-06-01

    The use of sintering additives has been the most effective way of promoting grain growth of uranium dioxide. We have established a same mechanism for additives which belongs to corundum structure: chromium, aluminium, vanadium and titanium sesquioxides. Study of thermodynamical stabilities of dopants has lead to define suitable sintering atmospheres in order to enhance grain growth. Low solubility limits have been defined at T=1700 deg C for four additives, from variations of final grain size versus initial dopant concentration Identification of second phase after cooling has been done from electronic diffraction patterns. It appears that these solubilities decrease sharply as positive deviation from stoichiometry of uranium dioxide increases. Dilatometric analysis of sintering of doped uranium dioxide has shown in certain cases some enhancement in densification rates, at the point of onset of abnormal grain growth, which is believed to be the source. Nevertheless, the following growth is accompanied with pores coalescence mechanisms and pores entrapment inside grains. Increased thermal stability, during standard annealing, is expected, limiting thereby redensification of nuclear fuel in reactors. Finally, from investigations of additives vaporizations, Al 2 O 3 and Cr 2 O 3 , oxygen exchanges between additives and matrix are believed to occur, which should lead to enhance pore mobility. (Author)., refs., figs., tabs

  13. Ballistic Phonon Penetration Depth in Amorphous Silicon Dioxide.

    Science.gov (United States)

    Yang, Lin; Zhang, Qian; Cui, Zhiguang; Gerboth, Matthew; Zhao, Yang; Xu, Terry T; Walker, D Greg; Li, Deyu

    2017-12-13

    Thermal transport in amorphous silicon dioxide (a-SiO 2 ) is traditionally treated as random walks of vibrations owing to its greatly disordered structure, which results in a mean free path (MFP) approximately the same as the interatomic distance. However, this picture has been debated constantly and in view of the ubiquitous existence of thin a-SiO 2 layers in nanoelectronic devices, it is imperative to better understand this issue for precise thermal management of electronic devices. Different from the commonly used cross-plane measurement approaches, here we report on a study that explores the in-plane thermal conductivity of double silicon nanoribbons with a layer of a-SiO 2 sandwiched in-between. Through comparing the thermal conductivity of the double ribbon samples with that of corresponding single ribbons, we show that thermal phonons can ballistically penetrate through a-SiO 2 of up to 5 nm thick even at room temperature. Comprehensive examination of double ribbon samples with various oxide layer thicknesses and van der Waals bonding strengths allows for extraction of the average ballistic phonon penetration depth in a-SiO 2 . With solid experimental data demonstrating ballistic phonon transport through a-SiO 2 , this work should provide important insight into thermal management of electronic devices.

  14. Ganglion dynamics and its implications to geologic carbon dioxide storage.

    Science.gov (United States)

    Wang, Yifeng; Bryan, Charles; Dewers, Thomas; Heath, Jason E; Jove-Colon, Carlos

    2013-01-02

    Capillary trapping of a nonwetting fluid phase in the subsurface has been considered as an important mechanism for geologic storage of carbon dioxide (CO(2)). This mechanism can potentially relax stringent requirements for the integrity of cap rocks for CO(2) storage and therefore can significantly enhance storage capacity and security. We here apply ganglion dynamics to understand the capillary trapping of supercritical CO(2) (scCO(2)) under relevant reservoir conditions. We show that, by breaking the injected scCO(2) into small disconnected ganglia, the efficiency of capillary trapping can be greatly enhanced, because the mobility of a ganglion is inversely dependent on its size. Supercritical CO(2) ganglia can be engineered by promoting CO(2)-water interface instability during immiscible displacement, and their size distribution can be controlled by injection mode (e.g., water-alternating-gas) and rate. We also show that a large mobile ganglion can potentially break into smaller ganglia due to CO(2)-brine interface instability during buoyant rise, thus becoming less mobile. The mobility of scCO(2) in the subsurface is therefore self-limited. Vertical structural heterogeneity within a reservoir can inhibit the buoyant rise of scCO(2) ganglia. The dynamics of scCO(2) ganglia described here provides a new perspective for the security and monitoring of subsurface CO(2) storage.

  15. Gas-phase Crystallization of Titanium Dioxide Nanoparticles

    International Nuclear Information System (INIS)

    Ahonen, P.P.; Moisala, A.; Tapper, U.; Brown, D.P.; Jokiniemi, J.K.; Kauppinen, E.I.

    2002-01-01

    We have investigated the development of crystal morphology and phase in ultrafine titanium dioxide particles. The particles were produced by a droplet-to-particle method starting from propanolic titanium tetraisopropoxide solution, and calcined in a vertical aerosol reactor in air. Mobility size classified 40-nm diameter particles were conveyed to the aerosol reactor to investigate particle size changes at 20-1200 deg. C with 5-1-s residence time. In addition, polydisperse particles were used to study morphology and phase formation by electron microscopy. According to differential mobility analysis, the particle diameter was reduced to 21-23-nm at 600 deg. C and above. Precursor decomposition occurred between 20 deg. C and 500 deg. C. The increased mobility particle size at 700 deg. C and above was observed to coincide with irregular particles at 700 deg. C and 800 deg. C and faceted particles between 900 deg. C and 1200 deg. C, according to transmission electron microscopy. The faceted anatase particles were observed to approach a minimized surface energy by forming {101} and {001} crystallographic surfaces. Anatase phase was observed at 500-1200 deg. C and above 600 deg. C the particles were single crystals. Indications of minor rutile formation were observed at 1200 deg. C. The relatively stable anatase phase vs. temperature is attributed to the defect free structure of the observed particles and a lack of crystal-crystal attachment points

  16. Particle length-dependent titanium dioxide nanomaterials toxicity and bioactivity

    Directory of Open Access Journals (Sweden)

    Buford Mary

    2009-12-01

    Full Text Available Abstract Background Titanium dioxide (TiO2 nanomaterials have considerable beneficial uses as photocatalysts and solar cells. It has been established for many years that pigment-grade TiO2 (200 nm sphere is relatively inert when internalized into a biological model system (in vivo or in vitro. For this reason, TiO2 nanomaterials are considered an attractive alternative in applications where biological exposures will occur. Unfortunately, metal oxides on the nanoscale (one dimension Results TiO2 nanospheres, short ( 15 μm nanobelts were synthesized, characterized and tested for biological activity using primary murine alveolar macrophages and in vivo in mice. This study demonstrates that alteration of anatase TiO2 nanomaterial into a fibre structure of greater than 15 μm creates a highly toxic particle and initiates an inflammatory response by alveolar macrophages. These fibre-shaped nanomaterials induced inflammasome activation and release of inflammatory cytokines through a cathepsin B-mediated mechanism. Consequently, long TiO2 nanobelts interact with lung macrophages in a manner very similar to asbestos or silica. Conclusions These observations suggest that any modification of a nanomaterial, resulting in a wire, fibre, belt or tube, be tested for pathogenic potential. As this study demonstrates, toxicity and pathogenic potential change dramatically as the shape of the material is altered into one that a phagocytic cell has difficulty processing, resulting in lysosomal disruption.

  17. Overcoming Barriers to Successfully Commercializing Carbon Dioxide Utilization

    Directory of Open Access Journals (Sweden)

    Marvin Kant

    2017-09-01

    Full Text Available The successful transition to a low-carbon economy hinges on innovative solutions and collaborative action on a global scale. Sustainable entrepreneurship is thereby recognized as a key driver in the creation and transformation of ecologically and socially sustainable economic systems. The purpose of this article is to contribute to this topic by understanding commercialization barriers for strong sustainability-oriented new technology ventures and to derive recommendations to overcome them. A qualitative multilevel approach is applied to identify barriers and drivers within the internal dynamic capabilities of the organization and within the organization’s external stakeholders. A model of barriers has been developed based on semi-structured interviews with new carbon dioxide utilization ventures and associated industry players in Canada, the USA, and the European Economic Area. Resulting recommendations to facilitate the (re-design of a dedicated support system are proposed on four levels: (a actors, (b resources, (c institutional settings, and (d the coordination of the support system.

  18. Studies on the sintering behaviour of uranium dioxide powder compacts

    International Nuclear Information System (INIS)

    Das, P.; Chowdhury, R.

    1988-01-01

    Uranium dioxide fuel pellets are normally made from their precursor ammonium diuranate, followed by calcination, subsequent reduction to sinterable grade powders and a post operation treatment of pressing and sintering. The low temperature calcined powders, usually exhibiting non-crystalline behaviour (under X-ray diffraction studies) progressively transforms into a crystalline variety on subsequent heat treatment at higher temperature. It is observed however that powders calcined between 800 to 900 0 C exhibit enhanced densification behaviour when sintered at higher temperatures. The isothermal shrinkage versus time plot of the sintered compacts are well described by a hyperbolic relationship which takes care of the observed shrinkage (λ) as caused due to a cumulative effect from the initial sintering of the powder compacts at zero time (α) and that caused due to the structural transformation from a non-crystalline modification with increased thermal treatment (β). The derived equation is a modification of the sintering mechanism of the viscous flow type proposed by Frenkel, involving sintering of an amorphous phase, the viscosity of the latter is presumed to increase with increasing thermal treatment to assume the final modified form as λ=t/(α+βt), where t = time, λ = shrinkage and α and β are the unknown parameters. (orig.)

  19. 49 CFR 195.4 - Compatibility necessary for transportation of hazardous liquids or carbon dioxide.

    Science.gov (United States)

    2010-10-01

    ... hazardous liquids or carbon dioxide. 195.4 Section 195.4 Transportation Other Regulations Relating to... necessary for transportation of hazardous liquids or carbon dioxide. No person may transport any hazardous liquid or carbon dioxide unless the hazardous liquid or carbon dioxide is chemically compatible with both...

  20. Membranes for separation of carbon dioxide

    Science.gov (United States)

    Ku, Anthony Yu-Chung [Rexford, NY; Ruud, James Anthony [Delmar, NY; Ramaswamy, Vidya [Niskayuna, NY; Willson, Patrick Daniel [Latham, NY; Gao, Yan [Niskayuna, NY

    2011-03-01

    Methods for separating carbon dioxide from a fluid stream at a temperature higher than about 200.degree. C. with selectivity higher than Knudsen diffusion selectivity include contacting a porous membrane with the fluid stream to preferentially transport carbon dioxide. The porous membrane includes a porous support and a continuous porous separation layer disposed on a surface of the porous support and extending between the fluid stream and the porous support layer. The porous support comprises alumina, silica, zirconia, stabilized zirconia, stainless steel, titanium, nickel-based alloys, aluminum-based alloys, zirconium-based alloys or a combination thereof. Median pore size of the porous separation layer is less than about 10 nm, and the porous separation layer comprises titania, MgO, CaO, SrO, BaO, La.sub.2O.sub.3, CeO.sub.2, HfO.sub.2, Y.sub.2O.sub.3, VO.sub.z, NbO.sub.z, TaO.sub.z, ATiO.sub.3, AZrO.sub.3, AAl.sub.2O.sub.4, A.sup.1FeO.sub.3, A.sup.1MnO.sub.3, A.sup.1CoO.sub.3, A.sup.1NiO.sub.3, A.sup.2HfO.sub.3, A.sup.3 CeO.sub.3, Li.sub.2ZrO.sub.3, Li.sub.2SiO.sub.3, Li.sub.2TiO.sub.3, Li.sub.2HfO.sub.3, A.sup.4N.sup.1.sub.yO.sub.z, Y.sub.xN.sup.1.sub.yO.sub.z, La.sub.xN.sup.1.sub.yO.sub.z, HfN.sup.2.sub.yO.sub.z, or a combination thereof; wherein A is La, Mg, Ca, Sr or Ba; A.sup.1 is La, Ca, Sr or Ba; A.sup.2 is Ca, Sr or Ba; A.sup.3 is Sr or Ba; A.sup.4 is Mg, Ca, Sr, Ba, Ti or Zr; N.sup.1 is V, Nb, Ta, Cr, Mo, W, Mn, Si or Ge; N.sup.2 is V, Mo, W or Si; x is 1 or 2; y ranges from 1 to 3; and z ranges from 2 to 7.

  1. Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Viani, Brian

    2013-01-29

    A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

  2. Electrochemical Reactor for Producing Oxygen From Carbon Dioxide, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — An electrochemical reactor is proposed by MicroCell Technologies, LLC to electrochemically reduce carbon dioxide to oxygen. In support of NASA's advanced life...

  3. Carbon dioxide inhalation treatments of neurotic anxiety. An overview.

    Science.gov (United States)

    Wolpe, J

    1987-03-01

    A lucky chance more than 30 years ago revealed the remarkable efficacy of single inhalations of high concentrations of carbon dioxide in eliminating or markedly reducing free-floating anxiety. The reduction of anxiety lasts for days, weeks, or longer--well beyond the persistence of carbon dioxide in the body. The effects are explicable on the hypothesis that free-floating anxiety is anxiety conditioned to continuously present sources of stimulation, such as background noise or the awareness of space or time, and that the anxiety response habit is weakened when the anxiety is inhibited by the competition of responses that carbon dioxide induces. More recently, it has become apparent that inhalations of carbon dioxide, applied in a different manner, are effective in overcoming maladaptive anxiety responses to specific stimuli, e.g., social stimuli. The substance is also proving to be a valuable resource in the treatment of the common variety of panic attacks.

  4. Monthly Carbon Dioxide in Troposphere (AIRS on AQUA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon dioxide (CO2) is an important greenhouse gas released through natural processes such as respiration and volcano eruptions and through huma activities such as...

  5. Induction of ovoviviparity in Rhabditis by sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J T; Tsui, R K

    1968-01-01

    While investigating the influence of atmospheric pollutants on soil and plant microbiotas, ovoviviparity was observed in the saprophagous nematode, Rhabditis sp., after exposure to various concentrations of sulfur dioxide.

  6. Studies on carbon dioxide system in central Arabian sea

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; Singbal, S.Y.S.

    significantly with depth Bicarbonate ion is quantitatively the major component of the carbon dioxide system The observed vertical distributions are discussed in terms of biological and geochemical processes in the sea...

  7. Energy costs of carbon dioxide concentrating mechanisms in aquatic organisms

    Czech Academy of Sciences Publication Activity Database

    Raven, John A.; Beardall, J.; Giordano, Mario

    2014-01-01

    Roč. 121, 2-3 (2014), s. 111-124 ISSN 0166-8595 Institutional support: RVO:61388971 Keywords : carbon dioxide * environmental change * radiation Subject RIV: EE - Microbiology, Virology Impact factor: 3.502, year: 2014

  8. Quantitative aspects of oxygen and carbon dioxide exchange ...

    African Journals Online (AJOL)

    Quantitative aspects of oxygen and carbon dioxide exchange through the ... ceratophthalmus (Crustacea: Decapoda) during rest and exercise in water and ... intersects zero time on the x-axis, indicating rapid gas exchange at the lung surface.

  9. Carbon dioxide and water vapour characteristics on the west coast ...

    Indian Academy of Sciences (India)

    Carbon dioxide, water vapour, air temperature and wind measurements at 10 Hz sampling rate were carried out over the ... seasonal and annual variations in the CO2 bal- ance. Hence, it is .... motion below produced by shear stress near the.

  10. Preliminary study of varietal susceptibility to sulfur dioxide

    International Nuclear Information System (INIS)

    Miller, J.E.; Xerikos, P.B.

    1976-01-01

    The injury response of plants to air pollutants, such as sulfur dioxide, is known to vary in severity and type for different varieties or cultivars of a species. Differences in the susceptibility of soybean varieties to sulfur dioxide have previously been noted, but sufficient information is not available concerning the sulfur dioxide resistance of varieties commonly grown in the Midwest. Results are reported from preliminary experiments concerning acute sulfur dioxide effects on 12 soybean varieties. The injury symptoms ranged from cream colored necrotic lesions (generally on younger leaves) to a reddish brown necrotic stipling (on older leaves). Differences in the severity of symptom development for the varieties was evident on both the younger and older leaves. No injury was apparent with three of the varieties

  11. Gas flaring: Carbon dioxide contribution to global warming ...

    African Journals Online (AJOL)

    Journal Home > Vol 20, No 2 (2016) > ... The quantitative method of analysis showed that carbon dioxide from gas ... gas flaring cause environmental degradation, health risks and constitute financial loss to the local oil producing communities.

  12. ISLSCP II Air-Sea Carbon Dioxide Gas Exchange

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the calculated net ocean-air carbon dioxide (CO2) flux and sea-air CO2 partial pressure (pCO2) difference. The estimates are based on...

  13. Carbon dioxide and nitrous oxide in the North Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; Naqvi, S.W.A; Jayakumar, D.A; George, M.D.; Narvekar, P.V.; DeSousa, S

    The understanding of biogeochemical cycling of carbon dioxide and nitrous oxide in the oceans is essential for predicting the fate of anthropogenically emitted components. The North Indian Ocean, with its diverse regimes, provides us with a natural...

  14. Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

    OpenAIRE

    Jeena, Vineet; Robinson, Ross S

    2009-01-01

    Summary The application of titanium dioxide as an oxidant in tandem oxidation type processes is described. Under microwave irradiation, quinoxalines have been synthesized in good yields from the corresponding ?-hydroxyketones.

  15. Dose-response relationships of acute exposure to sulfur dioxide

    International Nuclear Information System (INIS)

    Englehardt, F.R.; Holliday, M.G.

    1981-01-01

    Acute toxicity effects of sulphur dioxide are reviewed, and the derivation of a dose-lethality curve (presented as LC 50 vs. time) for human exposure to sulphur dioxide is attempted for periods ranging from ten seconds to two hours. As an aid to assessment of the hazards involved in operating heavy water manufacturing facilities, the fact that sulphur dioxide would be produced by the combustion of hydrogen sulphide was briefly considered in an appendix. It is suggested that sulphuric acid, a much more toxic substance than sulphur dioxide, may also be formed in such an event. It is concluded, therefore, that an overall hazard evaluation may have to address the contributory effects of sulphuric acid. (author)

  16. Gas Flaring: Carbon dioxide Contribution to Global Warming ...

    African Journals Online (AJOL)

    PROF HORSFALL

    emissions resulting from high consumption of fossil fuels. Flaring been a ... method of analysis showed that carbon dioxide from gas flaring constitute 1% of the total ... Although of these, methane is potentially the most .... in some gas plants.

  17. The effect of cutting on carbon dioxide absorption and carbohydrate ...

    African Journals Online (AJOL)

    grass) and Osteospermun sinuatum (Karoo-bush) plants during the flag leaf and flower bud stages respectively resulted in a sharp decline in net carbon dioxide absorption. As new photosynthetic material was produced the total carbon ...

  18. Drying of supercritical carbon dioxide with membrane processes

    NARCIS (Netherlands)

    Lohaus, Theresa; Scholz, Marco; Koziara, Beata; Benes, Nieck Edwin; Wessling, Matthias

    2015-01-01

    In supercritical extraction processes regenerating the supercritical fluid represents the main cost constraint. Membrane technology has potential for cost efficient regeneration of water-loaded supercritical carbon dioxide. In this study we have designed membrane-based processes to dehydrate

  19. A Carbon Dioxide Laser Bibliography, 1964-1969,

    Science.gov (United States)

    A bibliography concerning carbon dioxide lasers has been compiled covering the period 1964 through 1969. The chronologically listed references have also been catalogued into an author index and a subject index. (Author)

  20. Robust optical carbon dioxide isotope analyzer, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Isotopic analysis of carbon dioxide is an important tool for characterization of the exchange and transformation of carbon between the biosphere and the atmosphere....