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1

Chemistry of Carbon Gases in Volcanic Gases on Io  

Microsoft Academic Search

We use chemical equilibrium calculations to model the chemistry of carbon in volcanic gases on Io (Schaefer and Fegley 2004, ApJ, in review). The calculations covered temperatures from 500 - 2000 K, pressures from 10-8 to 10+2 bars, and bulk O\\/S atomic ratios from ˜ 0 to 3. These conditions overlap the nominal conditions at Pele, where T = 1760

L. Schaefer; B. Fegley Jr.

2004-01-01

2

Rare gases, water, and carbon in kaersutites  

Microsoft Academic Search

Kaersutites from Kakanui, New Zealand and from three localities in the southwestern United States have been analyzed for rare gases, water and carbon to investigate the volatile signature of the sub-continental mantle. This study does not confirm the high 3He\\/4He and 21Ne\\/22Ne ratios reported by Saito et al. [1] for the Kakanui kaersutite. Instead, a 3He\\/4He ratio of 6 RA

Robert J. Poreda; Asish R. Basu

1984-01-01

3

Adsorption of Gases on Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

This research focus in studying the interaction between various classical and quantum gases with novel carbon nanostructures, mainly carbon nanotubes (CNTs). Since their discovery by the Japanese physicist Sumio Iijima [1] carbon nanotubes have, experimentally and theoretically, been subjected to many scientific investigation. Studies of adsorption on CNTs are particularly directed toward their better usage in gas storage, gas separation, catalyst, drug delivery, and water purification. We explore the adsorption of different gases entrapped in a single, double, or multi-bundles of CNTs using computer simulations. The first system we investigate consists of Ar and Kr films adsorbed on zigzag or armchair nanotubes. Our simulations revealed that Kr atoms on intermediate size zigzag NTs undergo two phase transitions: A liquid-vapor (L?V), and liquid-commensurate (L?CS) with a fractional coverage of one Kr atoms adsorbed for every four carbon atoms. For Ar on zigzag and armchair NTs, the only transition observed is a L?V. In the second problem, we explore the adsorption of CO2 molecules in a nanotube bundle and calculate the isosteric heat of adsorption of the entrapped molecules within the groove. We observed that the lower the temperature, the higher the isosteric of adsorption. Last, we investigate the adsorption of hydrogen, Helium, and Neon gases on the groove site of two parallel nanotubes. At low temperature, the transverse motion on the plane perpendicular to the tubes' axis is frozen out and as a consequence, the heat capacity is reduced to 1/2. At high temperature, the atoms gain more degree of freedom and as a consequence the heat capacity is 5/2.

Mbaye, Mamadou Thiao

4

Clostridium stain which produces acetic acid from waste gases  

DOEpatents

A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

Gaddy, James L. (2207 Tall Oaks Dr., Fayetteville, AR 72703)

1997-01-01

5

Clostridium strain which produces acetic acid from waste gases  

DOEpatents

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 4 figs.

Gaddy, J.L.

1997-01-14

6

Rare gases, water, and carbon in kaersutites  

NASA Astrophysics Data System (ADS)

Kaersutites from Kakanui, New Zealand and from three localities in the southwestern United States have been analyzed for rare gases, water and carbon to investigate the volatile signature of the sub-continental mantle. This study does not confirm the high 3He/ 4He and 21Ne/ 22Ne ratios reported by Saito et al. [1] for the Kakanui kaersutite. Instead, a 3He/ 4He ratio of 6 RA and atmospheric 21Ne/ 22Ne ratios were measured which are consistent with our current knowledge of the earth's mantle. A low 40Ar/ 36Ar of 320 and more than 10 -8 cm 3/g of 36Ar confirms the argon results of Saito et al. and indicates that significant quantities of 36Ar reside in this portion of the mantle. Kaersutites from the southwestern United States (Arizona) have a heterogeneous helium isotope signature, ranging from 8.8 RA at San Carlos to 0.46 at Hoover Dam. All D/H ratios for the water in kaersutites (-56‰ to -78‰) represent typical mantle values with no apparent correlation with 3He/ 4He. The correlation of increasing carbon content (140-400 ppm) with increasing ? 13C (-24.5‰ to -16.7‰) may reflect differences in the proportions of oxidized and reduced carbon in these samples.

Poreda, Robert J.; Basu, Asish R.

1984-07-01

7

Processes to remove acid forming gases from exhaust gases  

DOEpatents

The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO[sub 2]; (B) contacting the gas sample of step (A) comprising NO[sub 2] with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0 and 100 C at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environmentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed. 16 figs.

Chang, S.G.

1994-09-20

8

Processes to remove acid forming gases from exhaust gases  

DOEpatents

The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO.sub.2 ; (B) contacting the gas sample of step (A) comprising NO.sub.2 with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0.degree. and 100.degree. C. at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environ-mentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed.

Chang, Shih-Ger (El Cerrito, CA)

1994-01-01

9

Use of salt hydrates as reversible absorbents of acid gases  

SciTech Connect

This patent describes a process for removing acid gases selected from the group consisting of CO{sub 2}, H{sub 2}S, SO{sub 2}, HCN, and COS from a gas mixture containing one or more of the gases and at least one other component. It comprises bringing the gas mixture into contact with a hydrated salt and carrying out the process at a temperature from 0{degrees} to 200{degrees}C whereby the salt hydrate reversibly absorbs the acid gases thereby removing them from the gas mixture.

Quinn, R.; Pez, G.P.

1990-11-27

10

Method for removing acid gases from a gaseous stream  

DOEpatents

In a process for hydrocracking a heavy aromatic polynuclear carbonaceous feedstock containing reactive alkaline constituents to produce liquid hydrocarbon fuels boiling below about 475.degree. C. at atmospheric pressure by contacting the feedstock with hydrogen in the presence of a molten metal halide catalyst, thereafter separating a gaseous stream containing hydrogen, at least a portion of the hydrocarbon fuels and acid gases from the molten metal halide and regenerating the molten metal halide, thereby producing a purified molten metal halide stream for recycle to the hydrocracking zone, an improvement comprising; contacting the gaseous acid gas, hydrogen and hydrocarbon fuels-containing stream with the feedstock containing reactive alkaline constituents to remove acid gases from the acid gas containing stream. Optionally at least a portion of the hydrocarbon fuels are separated from gaseous stream containing hydrogen, hydrocarbon fuels and acid gases prior to contacting the gaseous stream with the feedstock.

Gorin, Everett (San Rafael, CA); Zielke, Clyde W. (McMurray, PA)

1981-01-01

11

21 CFR 201.161 - Carbon dioxide and certain other gases.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Carbon dioxide and certain other gases. 201.161...LABELING Other Exemptions § 201.161 Carbon dioxide and certain other gases. (a) Carbon dioxide, cyclopropane, ethylene,...

2012-04-01

12

21 CFR 201.161 - Carbon dioxide and certain other gases.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Carbon dioxide and certain other gases. 201.161...LABELING Other Exemptions § 201.161 Carbon dioxide and certain other gases. (a) Carbon dioxide, cyclopropane, ethylene,...

2014-04-01

13

21 CFR 201.161 - Carbon dioxide and certain other gases.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Carbon dioxide and certain other gases. 201.161...LABELING Other Exemptions § 201.161 Carbon dioxide and certain other gases. (a) Carbon dioxide, cyclopropane, ethylene,...

2010-04-01

14

21 CFR 201.161 - Carbon dioxide and certain other gases.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Carbon dioxide and certain other gases. 201.161...LABELING Other Exemptions § 201.161 Carbon dioxide and certain other gases. (a) Carbon dioxide, cyclopropane, ethylene,...

2013-04-01

15

21 CFR 201.161 - Carbon dioxide and certain other gases.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Carbon dioxide and certain other gases. 201.161...LABELING Other Exemptions § 201.161 Carbon dioxide and certain other gases. (a) Carbon dioxide, cyclopropane, ethylene,...

2011-04-01

16

Diffusion of cis-5,8,11,14,17-eicosapentaenoic acid (1); carbon dioxide (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) cis-5,8,11,14,17-eicosapentaenoic acid; (2) carbon dioxide

Winkelmann, J.

17

Molecular Structure of Carbonic acid  

NSDL National Science Digital Library

The hypothetical acid formed with carbon dioxide and water; it is only in the H2CO3 form when in solution. This acid is found in everyday products, the most prominent of which include carbonated beverages. The conversion of carbonic acid into water and carbon dioxide in sodas is the reason the beverage looses the bubbling.

2002-09-10

18

Carbon isotopic composition of deep carbon gases in an ombrogenous peatland, northwestern Ontario, Canada  

SciTech Connect

Radiocarbon dating and carbon isotope analyses of deep peat and gases in a small ombrogenous peatland in northwestern Ontario reveals the presence of old gases at depth that are 1000-2000 yr younger than the enclosing peat. The authors suggest that the most likely explanation to account for this age discrepancy is the downward movement by advection of younger dissolved organic carbon for use by fermentation and methanogens bacteria. This study identifies a potentially large supply of old carbon gases in peatlands that should be considered in global carbon models of the terrestrial biosphere.

Aravena, R. (Univ. of Waterloo, Ontario (Canada). Center for Groundwater Research and Wetlands Research Center); Warner, B.G. (Univ. of Waterloo, Ontario (Canada). Wetlands Research Center and Dept. of Geography); Charman, D.J. (Univ. of Plymouth, Devon (United Kingdom). Dept. of Geographical Sciences); Belyea, L.R. (Queen Mary and Westfield College, London (United Kingdom). School of Biological Sciences); Mathur, S.P. (Foxleigh Crescent, Kanata, Ontario (Canada)); Dinel, H. (Center for Land and Biological Resources Research, Agriculture Canada, Ontario (Canada))

1993-01-01

19

Process for removal of ammonia and acid gases from contaminated waters  

DOEpatents

Contaminating basic gases, i.e., ammonia, and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with steam, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

King, C. Judson (Kensington, CA); MacKenzie, Patricia D. (Berkeley, CA)

1985-01-01

20

Process for removal of ammonia and acid gases from contaminated waters  

DOEpatents

Contaminating basic gases, i.e., ammonia and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with stream, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

King, C.J.; Mackenzie, P.D.

1982-09-03

21

MULTIPOLLUTANT MERCURY AND ACID GASES CONTROL TECHNOLOGY  

EPA Science Inventory

Plans are to continue testing for acid gas, mercury and NOx removal on baseline CFB operation with lime slurry, then use modified lime hydrates and slurries, and modified calcium silicates as additives for enhanced mercury and SO2 removal. Also, data from a coal-fired utility b...

22

ACID GASES IN CO2-RICH SUBSURFACE GEOLOGIC ENVIRONMENTS  

SciTech Connect

The analysis of species behavior involving dilute fluid environments has been crucial for the advance of modern solvation thermodynamics through molecular-based formalisms to guide the development of macroscopic regression tools in the description of fluid behavior and correlation of experimental data (Chialvo 2013). Dilute fluid environments involving geologic formations are of great theoretical and practical relevance regardless of the thermodynamic state conditions. The most challenging systems are those involving highly compressible and reactive confined environments, i.e., where small perturbations of pressure and/or temperature can trigger considerable density changes. This in turn can alter significantly the species solvation, their preferential solvation, and consequently, their reactivity with one another and with the surrounding mineral surfaces whose outcome is the modification of the substrate porosity and permeability, and ultimately, the integrity of the mineral substrates. Considering that changes in porosity and permeability resulting from dissolution and precipitation phenomena in confined environments are at the core of the aqueous CO2-mineral interactions, and that caprock integrity (e.g., sealing capacity) depends on these key parameters, it is imperative to gain fundamental understanding of the mineral-fluid interfacial phenomena and fluid-fluid equilibria under mineral confinement at subsurface conditions. In order to undertand the potential effects of acid gases as contaminants of supercritical CO2 streams, in the next section we will discuss the thermodynamic behavior of CO2 fluid systems by addressing two crucial issues in the context of carbon capture, utilization and sequestration (CCUS) technologies: (i) Why should we consider (acid gas) CO2 impurities? and (ii) Why are CO2 fluid - mineral interactions of paramount relevance?

Chialvo, Ariel A [ORNL] [ORNL; Vlcek, Lukas [ORNL] [ORNL; Cole, David [Ohio State University] [Ohio State University

2013-01-01

23

40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2010 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...affected facility any gases that contain nitrogen oxides in excess of the emission...

2010-07-01

24

40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2013 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...affected facility any gases that contain nitrogen oxides in excess of the emission...

2013-07-01

25

40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2014 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...affected facility any gases that contain nitrogen oxides in excess of the emission...

2014-07-01

26

40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2011 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...affected facility any gases that contain nitrogen oxides in excess of the emission...

2011-07-01

27

40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2012 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...affected facility any gases that contain nitrogen oxides in excess of the emission...

2012-07-01

28

Carbonic acid on Mars?  

NASA Astrophysics Data System (ADS)

For a long time carbonic acid (H 2CO 3) had defied many efforts for its detection by IR spectroscopic techniques. Recently H 2CO 3 has been synthesized at low temperature (?10-80 K), and stabilized up to ?250 K, by energetic ion irradiation of frozen targets made of H 2O:CO 2 ice mixtures (Moore and Khanna, Spectrochim. Acta47, 255-262, 1991; Moore et al., J, Geophys. Res.96(2), 17,541-17,545, 1991, DelloRusso et al., Geophys. Res.98(E3), 5505-5510, 1993; Brucato et al., Icarus 1996 (in press)) and by protonation of bicarbonate (Hage et al., J. Am. Chem. Soc.115, 8427-8431, 1993; J. Chem. Soc. Faraday Trans.91(17), 2823-2826, 1995). Its IR spectrum has been obtained. A comparison between the IR laboratory spectrum of H 2CO 3 with some spectra of Mars suggests that carbonic could be present on the surface and/or atmosphere of the red planet. Its firm identification requires the acquisition of better astronomical data possibly from space missions (e.g. Mars 96) and would be of primary relevance for both the organic and inorganic chemistry taking place on Mars.

Strazzulla, G.; Brucato, J. R.; Cimino, G.; Palumbo, M. E.

1996-11-01

29

Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid  

DOEpatents

Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

Chang, Shih-Ger (El Cerrito, CA); Liu, David K. (San Pablo, CA)

1992-01-01

30

Biological production of acetic acid from waste gases with Clostridium ljungdahlii  

DOEpatents

A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

Gaddy, James L. (Fayetteville, AR)

1998-01-01

31

Biological production of acetic acid from waste gases with Clostridium ljungdahlii  

DOEpatents

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 5 figs.

Gaddy, J.L.

1998-09-15

32

Nadir Sounding of Carbon Gases using SCIAMACHY Near Infrared Channels  

NASA Astrophysics Data System (ADS)

The Beer InfraRed Retrieval Algorithm (BIRRA) and Column EstimatoR Vertical InfraRed Sounding Atmosphere (CERVISA) codes have been designed to retrieve vertical column den-sities (VCDs) of atmospheric gases in the near and thermal infrared (NIR,TIR) region of the electromagnetic spectrum by means of non-linear least squares fitting of radiances. As part of the operational SCIAMACHY level 1-2 processor, BIRRA is currently used for the specific retrieval of carbon monoxide (CO) VCDs exploiting the fitting window 4282-4301 cm-1 within the SCIAMACHY channel 8. Using appropriate fitting windows in channel 6, BIRRA also allows to gain information on greenhouse gases such as methane and carbon dioxide. Unfortunately, the increasing number of dead and bad pixels -specially in the NIR channels -reduces the available spectral information and consequently makes the VCDs retrieval more and more challenging. The proper choice of the pixel mask, fitting window, auxiliary fit parameters, as well as the filtering of the Level 2 data is crucial for obtaining a high quality atmospheric product. For validation of BIRRA the closely related CERVISA code is used to retrieve CO and CH4 from nadir infrared sounding data of AIRS, IASI, or TES. BIRRA and CERVISA share a large portion of modules, e.g., for line-by-line absorption and the nonlinear least squares solver; the essential difference is the part of the forward model devoted to radiative transfer through the atmosphere, i.e., Beer's law for the NIR versus Schwarzschild's equation for the TIR. CERVISA retrieval results are compared both to the operational products of the TIR sounder and to the SCIAMACHY-BIRRA product. In this work, we present recent results of carbon monoxide and methane retrievals.

Gimeno García, Sebastián; Schreier, Franz; Lichtenberg, Günter; Slijkhuis, Sander; Hess, Michael; Aberle, Bernd

33

Carbon isotopes of hydrocarbons and carbon dioxide in natural gases in China  

NASA Astrophysics Data System (ADS)

130 natural gases in the continent of China were determined for the abundance and carbon isotopes of hydrocarbons and carbon dioxide. The ?13C (PDB) values of methane range from -68 to - 24.4%, and the largest isotopic variability for hydrocarbons is of ?13C 1 < ?13C; < ?13C; < ?13C 4 < ?13C 5. These characteristics suggest that the gaseous hydrocarbons originated principally from thermal and or microbial decomposition of organic matter. The wide variations of ?13C 0 distribution patterns (n = 1, 2, 3, 4 and 5) can be explained by (1) extensive mixture between thermogenic and microbial gases, or between thermogenic gases produced during different thermal stage, and or (2) preferential microbial oxidation. There is no direct evidence for the presence of abiogenic hydrocarbon in natural gases in China. One sample from Songliao basin shows a heavier ?13C 1 ( - 24‰) and reverse isotopic distribution pattern ( ?13C 1 > ?13C 2 > ?13C 3). Concerning the occurrence of mantle-derived He, Ne, Ar and Xe in the south Songliao basin, we propose that the methane mantle derived and heavy hydrocarbons (ethane, propane, butane, etc.) formed from polymerization of the mantle-derived methane. The ?13C values for carbon dioxide range from - 13.9 to + 13.5‰ suggesting the multiple origins. Gases with CO 2 concentrations greater than 10% have a narrow range of ?13C values, from - 8 to - 2‰, and show higher 1He 4He ratios ( > 0.1 times the atmospheric value), suggesting that a mantle-derived component is diluted by CO 2 derived from carbonate and or organic matter. Positive ?13C values ( + 4 - + 14‰) indicate CO 2 reduction to CH 2, CO 2 with trace concentration in CH 4-rich gases can be attributed to microbial decomposition of organic matter in sedimentary rocks.

Sheng, Xu; Nakai, Shun'ichi; Wakita, Hiroshi; Yongchang, Xu; Wang, Xianbin

1997-02-01

34

Plasma-chemical waste treatment of acid gases  

Microsoft Academic Search

The research to date has shown that a HâS waste-treatment process based on plasma-chemical dissociation technology is compatible with refinery and high-carbon-oxide acid-gas streams. The minor amounts of impurities produced in the plasma-chemical reactor should be treatable by an internal catalytic reduction step. Furthermore, the plasma-chemical technology appears to be more efficient and more economical than the current technology. The

J. B. L. Harkness; R. D; E. J. Daniels

1993-01-01

35

Removal of mercury from stack gases by activated carbon  

SciTech Connect

On combustion, the trace elements in the incinerator feed stream are partitioned between the bottom ash (slag) stream, and a flue gas stream containing suspended fly ash and vapors of volatile elements or compounds. A further partitioning of the flue gas stream takes place in the particulate emission control devices that efficiently remove larger fly ash particles but are less efficient for vapors and finer particles. Environmental control agencies, researchers, and general public have become increasingly concerned with the mobilization of trace elements to the environment from solid and hazardous waste incinerators. Mercury is the trace element of particular concern since, during combustion, most of the mercury present in the influent stream is transferred into the vapor phase due to its high volatility. There is a considerable evidence in the literature that currently used pollution abatement technologies (flue gas clean-up and particulate control devices) are not capable of controlling gas phase mercury emissions. Activated carbon adsorption is a unit process that offers great promise for achieving high quality air emissions with respect to mercury and other trace elements that might be present in gases emitted from solid and hazardous waste incinerators. This study is designed to evaluate the rate of vapor-phase mercury removal by virgin and sulfur impregnated activated carbons under various process conditions. The specific process conditions that will be evaluated for their effect on the rate and mechanism of mercury uptake include temperature, moisture content, oxygen partial pressure, and presence of other compounds and trace elements in the vapor-phase. Accurate description of the kinetics of mercury removal by activated carbon is an essential component in establishing design procedures that would ensure successful application of this efficient technology for mercury control.

Vidic, R.D. [Univ. of Pittsburgh, PA (United States)

1995-10-01

36

40 CFR 60.54a - Standard for municipal waste combustor acid gases.  

Code of Federal Regulations, 2011 CFR

...for municipal waste combustor acid gases. 60.54a Section...for municipal waste combustor acid gases. (a)-(b) [Reserved...corrected to 7 percent oxygen (dry basis), whichever is less stringent...corrected to 7 percent oxygen (dry basis), whichever is less...

2011-07-01

37

40 CFR 60.54a - Standard for municipal waste combustor acid gases.  

Code of Federal Regulations, 2012 CFR

...for municipal waste combustor acid gases. 60.54a Section...for municipal waste combustor acid gases. (a)-(b) [Reserved...corrected to 7 percent oxygen (dry basis), whichever is less stringent...corrected to 7 percent oxygen (dry basis), whichever is less...

2012-07-01

38

40 CFR 60.54a - Standard for municipal waste combustor acid gases.  

Code of Federal Regulations, 2013 CFR

...for municipal waste combustor acid gases. 60.54a Section...for municipal waste combustor acid gases. (a)-(b) [Reserved...corrected to 7 percent oxygen (dry basis), whichever is less stringent...corrected to 7 percent oxygen (dry basis), whichever is less...

2013-07-01

39

40 CFR 60.54a - Standard for municipal waste combustor acid gases.  

Code of Federal Regulations, 2014 CFR

...for municipal waste combustor acid gases. 60.54a Section...for municipal waste combustor acid gases. (a)-(b) [Reserved...corrected to 7 percent oxygen (dry basis), whichever is less stringent...corrected to 7 percent oxygen (dry basis), whichever is less...

2014-07-01

40

40 CFR 60.54a - Standard for municipal waste combustor acid gases.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standard for municipal waste combustor acid gases. 60.54a Section 60.54a Protection of Environment... § 60.54a Standard for municipal waste combustor acid gases. (a)-(b) [Reserved] (c) On and...

2010-07-01

41

Joseph Black, carbon dioxide, latent heat, and the beginnings of the discovery of the respiratory gases.  

PubMed

The discovery of carbon dioxide by Joseph Black (1728-1799) marked a new era of research on the respiratory gases. His initial interest was in alkalis such as limewater that were thought to be useful in the treatment of renal stone. When he studied magnesium carbonate, he found that when this was heated or exposed to acid, a gas was evolved that he called "fixed air" because it had been combined with a solid material. He showed that the new gas extinguished a flame, that it could not support life, and that it was present in gas exhaled from the lung. Within a few years of his discovery, hydrogen, nitrogen, and oxygen were also isolated. Thus arguably Black's work started the avalanche of research on the respiratory gases carried out by Priestley, Scheele, Lavoisier, and Cavendish. Black then turned his attention to heat and he was the first person to describe latent heat, that is the heat added or lost when a liquid changes its state, for example when water changes to ice or steam. Latent heat is a key concept in thermal physiology because of the heat lost when sweat evaporates. Black was a friend of the young James Watt (1736-1819) who was responsible for the development of early steam engines. Watt was puzzled why so much cooling was necessary to condense steam into water, and Black realized that the answer was the latent heat. The resulting improvements in steam engines ushered in the Industrial Revolution. PMID:24682452

West, John B

2014-06-15

42

Carbon Compounds in Pyrolysates and Amino Acids in Extracts of Apollo 14 Lunar Samples  

Microsoft Academic Search

The analysis of seven samples brought back by the Apollo 14 astronauts is described. Carbon was present in the gases evolved to between 76 and 161 p.p.m. Glycine, aspartic acid, glutamic acid and serine were among the most abundant amnio acids found.

VINCENT E. MODZELESKI; JUDITH E. MODZELESKI; M. A. JABBAR MOHAMMED; LOIS ANNE NAGY; BARTHOLOMEW NAGY; WILLIAM S. McEWAN; HAROLD C. UREY; PAUL B. HAMILTON

1973-01-01

43

Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution  

DOEpatents

A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

Rau, Gregory Hudson (Castro Valley, CA)

2012-05-15

44

Permeability of Nafion{reg_sign} 117 equilibrated with phosphoric acid to methanol fuel cell gases  

SciTech Connect

The permeability of Nafion 117 pre-equilibrated with phosphoric acid to various gases of interest in fuel cell applications is reported. The permeability measurements were carried out using three different techniques: a sorption technique, a closed volume technique based on ASTM D-1434, and a swept volume technique based on ASTM D-3985. The permeabilities of O{sub 2}, CO{sub 2}, and CH{sub 3}OH over the temperature range of 80--200 C range from 26 to 71 barrer, from 7 to 40 barrer, and from 6,400 to 28,000 barrer, respectively. The permeability of the system to oxygen and carbon dioxide are large enough to minimize mass transport limitations within electrodes, but small enough to not cause significant crossover. Equivalent current density losses due to methanol crossover are about 50 mA/cm{sup 2}.

Lux, K.W.; Wainright, J.S.; Savinell, R.F.; Landau, U. [Case Western Reserve Univ., Cleveland, OH (United States)

1994-12-31

45

OPERATION OF A SULFURIC ACID PLANT USING BLENDED COPPER SMELTER GASES  

EPA Science Inventory

A high degree of control of SOx emissions at copper smelters can be obtained by blending reverberatory furnace gases with gases from roasters and converters and using the combined stream as feed to a sulfuric acid plant. The Bor Copper Smelter in Bor, Yugoslavia, experimented wit...

46

Greenhouse Gases  

MedlinePLUS

... CFCs CO Additional Information Introduction What are greenhouse gases? Many chemical compounds present in Earth's atmosphere behave ... a greenhouse gas. Carbon Monoxide and other reactive gases Carbon monoxide (CO) is not considered a direct ...

47

Atmospheric Trace Gases from the Carbon Dioxide Information Analysis Center (CDIAC)  

DOE Data Explorer

CDIAC products are indexed and searchable through a customized interface powered by ORNL's Mercury search engine. Products include numeric data packages, publications, trend data, atlases, models, etc. and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Some of the collections may also be included in the CDIAC publication, Trends Online: A Compendium of Global Change Data. Most data sets, many with numerous data files, are free to download from CDIAC's ftp area. The collections under the CDIAC heading of Atmospheric Trace Gases include: Atmospheric Carbon Dioxide, Atmospheric Methane, Atmospheric Carbon Monoxide, Atmospheric Hydrogen, Isotopes in Greenhouse Gases, Radionuclides, Aerosols, and Other Trace Gases.

48

Relation of Hydrogen and Methane to Carbon Monoxide in Exhaust Gases from Internal-Combustion Engines  

NASA Technical Reports Server (NTRS)

The relation of hydrogen and methane to carbon monoxide in the exhaust gases from internal-combustion engines operating on standard-grade aviation gasoline, fighting-grade aviation gasoline, hydrogenated safety fuel, laboratory diesel fuel, and auto diesel fuel was determined by analysis of the exhaust gases. Two liquid-cooled single-cylinder spark-ignition, one 9-cylinder radial air-cooled spark-ignition, and two liquid-cooled single-cylinder compression-ignition engines were used.

Gerrish, Harold C; Tessmann, Arthur M

1935-01-01

49

Process for the removal of acid forming gases from exhaust gases  

DOEpatents

Exhaust gases are treated to remove NO or NO[sub x] and SO[sub 2] by contacting the gases with an aqueous emulsion or suspension of yellow phosphorus preferably in a wet scrubber. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50 C is attractive. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO[sub x] and SO[sub 2], alkalis that are used for flue gas desulfurization are preferred. With this process, 100% of the by-products created are usable, and close to 100% of the NO or NO[sub x] and SO[sub 2] can be removed in an economic fashion. 9 figs.

Chang, S.G.; Liu, D.K.

1992-11-17

50

Process for the removal of acid forming gases from exhaust gases  

DOEpatents

Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorus preferably in a wet scrubber. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. are attractive. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, 100% of the by-products created are usable, and close to 100% of the NO or NO and SO.sub.2 can be removed in an economic fashion.

Chang, Shih-Ger (El Cerrito, CA); Liu, David K. (San Pablo, CA)

1992-01-01

51

Helium, Argon, and Carbon in Some Natural Gases  

Microsoft Academic Search

Thirty-nine samples of natural gases representing varied chemical compositions and geological occurrences were analyzed for their helium, radiogenic argon, and atmospheric argon contents. The total range in the (He\\/A)rd ratio was found to be 1.6 to 130 with most samples having values between 6 and 25. This range of values is essentially equal to the production ratio from the uranium,

R. E. Zartman; G. J. Wasserburg; J. H. Reynolds

1961-01-01

52

Intrapore reaction of carbon fibers with oxygen-containing gases  

SciTech Connect

A study has been made of the conditions of the internal reaction of carbon fiber obtained from polyacrylonitrile under various conditions of heat thermal treatment (the final temperature was varied from 880/sup 0/C to 2400/sup 0/C) with gaseous oxidizing agents: atmospheric oxygen, carbon dioxide, and steam.

Elchina, V.I.; Fridman, L.I.; Gurdzhiyants, V.M.; Ivin, V.D.; Levit, R.M.; Samoilova, N.A.; Yavorskii, I.A.

1983-01-01

53

Chemical coupling between ammonia, acid gases, and fine particles Bok Haeng Baek, Viney P. Aneja*, Quansong Tong  

E-print Network

. The observational based analysis of ammonia, acid gases, and fine particles by annular denuder system (ADS) coupled). Ammonia gas is the dominant trace gas capable of neutralizing the acid gases produced by the oxidation acid (HNO3) produced by neutralization processes with atmospheric ammonia become atmospheric aerosols

Aneja, Viney P.

54

Natural sources of greenhouse gases: carbon dioxide emissions from volcanoes  

USGS Publications Warehouse

Volcanic degassing of carbon dioxide plays an important role in keeping the atmosphere-ocean portion of the carbon geochemical cycle in balance. The atmosphere-ocean carbon deficit requires replenishment of 6??1012 mol CO2/yr, and places an upper limit on the output of carbon dioxide from volcanoes. The CO2 output of the global mid-oceanic ridge system is ca. 0.7??1012 mol/yr, thus supplying only a fraction of the amount needed to balance the carbon deficit. The carbon dioxide flux from subaerial volcanoes is poorly known, but it appears to be at least as large as the mid-oceanic ridge flux. Much (perhaps most) of the CO2 emitted from volcanoes is degassed noneruptively. This mode of degassing may lead to impacts on the environment and biosphere that are fundamentally different in character from those envisioned in published scenarios, which are based on the assumption that CO2 degassing occurs predominantly by eruptive processes. Although the flux of carbon dioxide from volcanoes is poorly constrained at present, it is clearly two orders of magnitude lower than the anthropogenic output of CO2.

Gerlach, Terrence

1990-01-01

55

Acid sorption regeneration process using carbon dioxide  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Husson, Scott M. (Anderson, SC)

2001-01-01

56

Process for recovery of sulfur from acid gases  

DOEpatents

Elemental sulfur is recovered from the H.sub.2 S present in gases derived from fossil fuels by heating the H.sub.2 S with CO.sub.2 in a high-temperature reactor in the presence of a catalyst selected as one which enhances the thermal dissociation of H.sub.2 S to H.sub.2 and S.sub.2. The equilibrium of the thermal decomposition of H.sub.2 S is shifted by the equilibration of the water-gas-shift reaction so as to favor elemental sulfur formation. The primary products of the overall reaction are S.sub.2, CO, H.sub.2 and H.sub.2 O. Small amounts of COS, SO.sub.2 and CS.sub.2 may also form. Rapid quenching of the reaction mixture results in a substantial increase in the efficiency of the conversion of H.sub.2 S to elemental sulfur. Plant economy is further advanced by treating the product gases to remove byproduct carbonyl sulfide by hydrolysis, which converts the COS back to CO.sub.2 and H.sub.2 S. Unreacted CO.sub.2 and H.sub.2 S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H.sub.2 and CO, which has value either as a fuel or as a chemical feedstock and recovers the hydrogen value from the H.sub.2 S.

Towler, Gavin P. (Kirkbymoorside, GB2); Lynn, Scott (Pleasant Hill, CA)

1995-01-01

57

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

SciTech Connect

The Albany Research Center (ARC) of the US Department of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO{sub 2} pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185 C and a partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.

O'Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

2000-07-01

58

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

SciTech Connect

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.

O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

2000-01-01

59

Peatlands, carbon storage, greenhouse gases, and the Kyoto Protocol: Prospects and significance for Canada  

Microsoft Academic Search

The Kyoto Protocol accepts terrestrial sinks for greenhouse gases (GHGs) as offsets for fossil fuel emissions. Only carbon\\u000a sequestered in living biomass from re- and afforestation is presently considered, but the Protocol contains a provision for\\u000a the possible future inclusion of other land uses and soils. As a result, the possibility of sequestration of carbon in wetlands,\\u000a and particularly peatlands,

Nigel T. Roulet

2000-01-01

60

Steam Production from Waste Stack Gases in a Carbon Black Plant  

E-print Network

Waste stack gases from carbon black plant bag filters are used as fuel to produce superheated steam - G25 PSIG and 7500F. This steam is out into a steam header that serves Conoco plants in the Lake Charles, Louisiana area. Combustion of the waste...

Istre, R. I.

1981-01-01

61

Carbon and Conservation: Cropping systems and greenhouse gases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Quantifying and predicting soil carbon sequestration and greenhouse gas emissions from agricultural systems have been research goals for numerous institutions, especially since the turn of the millennium. Cost, time, and politics are variables that have limited the rapid development of robust quant...

62

SOLUBILITIES OF ACID GASES AND NITROGEN IN METHANOL  

EPA Science Inventory

The report describes a thermodynamic model, developed to predict the equilibrium behavior of carbon dioxide, hydrogen sulfide, nitrogen, and methanol mixtures. The model uses the four-suffix Margules equation to describe liquid-phase nonidealities and the Soave modification of th...

63

Pressure swing adsorption for carbon dioxide sequestration from exhaust gases  

Microsoft Academic Search

Carbon dioxide removal using pressure swing adsorption (PSA) processes were investigated both theoretically and experimentally. CO2 is the more strongly adsorbed compared to nitrogen in a flue gas with suitable molecular sieve adsorbents. Zeolite 13X was found to be suitable for CO2 sequestration on testing several adsorbents for sorption-based separation. Numerical simulations indicate that the purity of nitrogen gas recovered

Vincent G. Gomes; Kevin W. K. Yee

2002-01-01

64

Sorption of noble gases by solids, with reference to meteorites. II - Chromite and carbon. III - Sulfides, spinels, and other substances; on the origin of planetary gases  

NASA Technical Reports Server (NTRS)

The trapping of noble gases by chromite and carbon, two putative carriers of primordial noble gases in meteorites, was studied by synthesizing 19 samples in a Ne-Ar-Kr-Xe atmosphere at 440-720 K. Noble gas contents are found to approximately obey Henry's Law, but only slight correlations are found with composition, surface area, or adsorption temperature. Geometric mean distribution coefficients for bulk samples and HCl residues in 10 cu cm STP/g atm are: Xe 100, Kr 15, Ar 3.5, and Ne 0.62. Elemental fractionation data support the suggestion of Lewis et al. (1977) that chromite and carbon in C2 and C3 chondrites were formed by the reaction: Fe, Cr + 4CO yields (Fe, Cr)3O4 + 4C + carbides. In contrast to meteoritic minerals, the synthetic specimens show no isotopic fractionation of noble gases. In a subsequent study, attention is given to the cases of sulfides and spinels, on the way to consideration of the origin of planetary gases. Sulfides showed three distinctive trends relative to chromite or magnetite. The elemental fractionation pattern of Ar, Kr and Xe in meteorites, terrestrial rocks and planets resembles the adsorption patterns on the carbons, spinels, sulfides, and other solids studied. The high release temperature of meteoritic noble gases may be explained by transformation of the physisorbed or chemisorbed gas. The ready loss of meteoritic heavy gases on surficial oxidation is consistent with adsorption, as is the high abundance.

Yang, J.; Anders, E.

1982-01-01

65

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2010 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...plan shall include emission limits for nitrogen oxides at least as protective as...

2010-07-01

66

40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2010 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b...metals, acid gases, organics, and nitrogen oxides. (a) The limits for municipal...percent oxygen. (d) The limits for nitrogen oxides are specified in...

2010-07-01

67

40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2013 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b...metals, acid gases, organics, and nitrogen oxides. (a) The limits for municipal...percent oxygen. (d) The limits for nitrogen oxides are specified in...

2013-07-01

68

40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2012 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b...metals, acid gases, organics, and nitrogen oxides. (a) The limits for municipal...percent oxygen. (d) The limits for nitrogen oxides are specified in...

2012-07-01

69

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2012 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...plan shall include emission limits for nitrogen oxides at least as protective as...

2012-07-01

70

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2014 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...plan shall include emission limits for nitrogen oxides at least as protective as...

2014-07-01

71

40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2011 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b...metals, acid gases, organics, and nitrogen oxides. (a) The limits for municipal...percent oxygen. (d) The limits for nitrogen oxides are specified in...

2011-07-01

72

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2011 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...plan shall include emission limits for nitrogen oxides at least as protective as...

2011-07-01

73

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2013 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b...metals, acid gases, organics, and nitrogen oxides. (a) The emission limits...plan shall include emission limits for nitrogen oxides at least as protective as...

2013-07-01

74

40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.  

Code of Federal Regulations, 2014 CFR

...combustor metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b...metals, acid gases, organics, and nitrogen oxides. (a) The limits for municipal...percent oxygen. (d) The limits for nitrogen oxides are specified in...

2014-07-01

75

ARM Carbon Cycle Gases Flasks at SGP Site  

DOE Data Explorer

Data from flasks are sampled at the Atmospheric Radiation Measurement Program ARM, Southern Great Plains Site and analyzed by the National Oceanic and Atmospheric Administration NOAA, Earth System Research Laboratory ESRL. The SGP site is included in the NOAA Cooperative Global Air Sampling Network. The surface samples are collected from a 60 m tower at the ARM SGP Central Facility, usually once per week in the afternoon. The aircraft samples are collected approximately weekly from a chartered aircraft, and the collection flight path is centered over the tower where the surface samples are collected. The samples are collected by the ARM and LBNL Carbon Project.

Biraud, Sebastien

76

Exposure assessment of oxidant gases and acidic aerosols  

SciTech Connect

Clearly the presence of high ozone and acidic species in North America is primarily dependent upon photochemical air pollution. Evidence shows, however, that high acid exposures may occur in specific types of areas of high sulfur fuel use during the winter. At the present time, our concerns about exposure to local populations and regional populations should be directed primarily toward the outdoor activity patterns of individuals in the summer, and how those activity patterns relate to the location, duration, and concentrations of ozone and acid aerosol in photochemical air pollution episodes. Lioy Dyba and Mage et al have examined the activity patterns of children in summer camps. Because they spend more time outside than the normal population, these children form an important group of exercising individuals subject to photochemical pollution exposures. The dose of ozone inhaled by the children in the two camps was within 50% and 25% of the dose inhaled by adults in controlled clinical situations that produced clinically significant decrements in pulmonary function and increased the symptoms after 6.6 hr exposure in a given day. The chamber studies have used only ozone, whereas in the environment this effect may be enhanced by the presence of a complex mixture. The work of Lioy et al in Mendham, New Jersey found that hydrogen ion seemed to play a role in the inability of the children to return immediately to their normal peak expiratory flow rate after exposure. The camp health study conducted in Dunsville, Ontario suggested that children participating in a summer camp where moderate levels of ozone (100 ppb) but high levels of acid (46 micrograms/m3) occurred during an episode had a similar response. Thus, for children or exercising adults who are outdoors for at least one hour or more during a given day, the presence and persistence of oxidants in the environment are of particular concern. 63 references.

Lioy, P.J.

1989-01-01

77

A Laboratory Investigation of the Heterogeneous Reaction of Nitric Acid with Calcium Carbonate  

Microsoft Academic Search

Recent laboratory experiments on the heterogeneous reaction of nitric acid with calcium carbonate particles will be presented. Several different techniques are used to investigate and quantify morphology changes that occur during reaction, phase transformations, and the rate dependence of individual particles as a function of relative humidity. In addition, competitive reactions of other trace gases such as sulfur dioxide with

V. H. Grassian; B. J. Krueger; A. Preszler Prince; M. A. Young

2002-01-01

78

ARM-LBNL-NOAA Flask Sampler for Carbon Cycle Gases  

DOE Data Explorer

Data from ccg-flasks are sampled at the ARM SGP site and analyzed by the NOAA Earth System Research Laboratory (ESRL) as part of the NOAA Cooperative Global Air Sampling Network. Surface samples are collected from a 60m tower at the SGP Central Facility, usually once per week on one afternoon. The aircraft samples are collected approximately weekly from a chartered aircraft, and the collection flight path is centered over the tower where the surface samples are collected. Samples are collected by the ARM/LBNL Carbon Project. CO2 flask data contains measurements of CO2 concentration and CO2 stable isotope ratios (13CO2 and C18OO) from flasks collected at the SGP site. The flask samples are collected at 2m, 4m, 25m, and 60m along the 60m tower.

Torn, Margaret

79

Indoor and outdoor concentrations of inorganic acidic aerosols and gases  

SciTech Connect

Annular denuder-filter pack sampling systems were used to make indoor and outdoor measurements of aerosol strong H{sup +}, SO{sub 4}{sup 2{minus}}, NH{sub 4}{sup +}, NO{sub 3}{sup {minus}} and NO{sub 2}{sup {minus}}, and the gaseous pollutants SO{sub 2}, HNO{sub 3}, HONO and NH{sub 3} during summer and winter periods in Boston, Massachusetts. Outdoor levels of SO{sub 2}, HNO{sub 3}, H{sup +} and SO{sub 4}{sup 2{minus}} exceeded their indoor concentrations during both seasons. Winter indoor/outdoor ratios were lower than during the summer, probably due to lower air exchange rates during the winter period. During both monitoring periods, indoor/outdoor ratios of aerosol strong H{sub +} were 40-50% of the indoor/outdoor SO{sub 4}{sup 2{minus}} ratio. Since aerosol strong acidity is typically associated with SO{sub 4}{sup 2{minus}}, this finding is indicative of neutralization of the acidic aerosol by the higher indoor NH{sub 3} levels. Geometric mean indoor/outdoor NH{sub 3} ratios of 3.5 and 23 respectively were measured for the summer and winter sampling periods. For HONO, NH{sub 3}, NH{sub 4}{sup +} and NO{sub 2}{sup {minus}}, indoor concentrations were significantly higher than ambient levels. Indoor levels of NO{sub 3}{sup {minus}} were slightly less than outdoor concentrations.

Brauer, M.; Koutrakis, P.; Keeler, G.J.; Spengler, J.D. (Harvard Univ., Boston, MA (USA))

1991-02-01

80

Control of Effluent Gases from Solid Waste Processing Using Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

One of the major problems associated with solid waste processing technologies is the release of effluent gases and contaminants that are in gaseous formed from the processes. A number of other gases, in particular NO(x), SO2, NH3, Hydrocarbons (e.g. CH4) do present hazards to the crew in space habitats. Reduction of mass, power, volume and resupply can be achieved by using catalyst impregnated carbon nanotubes as compared to other catalytic systems. The development and characterization of an innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches. This is due to the ability to direct the selective uptake of gaseous species based on their controllable pore size, high adsorptive capacity and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. For example, SWNTs have high adsorptive capacity for NO and the adsorbed NO can be decomposed to N2 and O2 . Experimental results showing the decomposition of NO on metal impregnated carbon nanotubes is presented. Equivalent System Mass (ESM) comparisons are made of the existing TCCS systems with the carbon nanotube technology for removing NO(x). The potential for methane decomposition using carbon nanotubes catalysts is also discussed.

Fisher, John; Cinke, Martin; Wignarajab, Kanapathipillai

2005-01-01

81

Flame Synthesis of Carbon Nanotubes Using Low Calorific Value Gases  

SciTech Connect

Nanostructures formed in diffusion flames of pure fuels [CH{sub 4}, C{sub 3}H{sub 8}, and C{sub 2}H{sub 2}] at different fuel flow rates have been analyzed. Synthesis samples have been also collected from diffusion flames of various fuel blends [H{sub 2}-CH{sub 4}, H{sub 2}-CO, H{sub 2}-C{sub 3}H{sub 8}, H{sub 2}-C{sub 2}H{sub 2}] at different combustion conditions. SEM images of particulate samples collected from H{sub 2}-CH{sub 4} diffusion flames show formation of nanostructures. However, the formation of nanostructures only occurs at a narrow window of fuel compositions (< 10% H{sub 2} concentration in the mixture) and flow conditions (Jet Exit Reynolds number Re{sub j} = 200). At higher H{sub 2} concentration and flow velocity, formation of nanostructures diminishes and H{sub 2}-CH{sub 4} flames produce amorphous carbon and soot particles.

Jorge Camacho; Mahesh Subramanya; Ahsan R. Choudhuri

2007-03-31

82

Analysis of effluent gases during the CCVD growth of multi-wall carbon nanotubes from acetylene  

Microsoft Academic Search

Catalytic chemical vapor deposition was used to grow multi-walled carbon nanotubes on a Fe:Co:CaCO3 catalyst from acetylene. The influent and effluent gases were analyzed by gas chromatography and mass spectrometry at different time intervals during the nanotubes growth process in order to better understand and optimize the overall reaction. A large number of byproducts were identified and it was found

T. C. Schmitt; A. S. Biris; D. W. Miller; A. R. Biris; D. Lupu; S. Trigwell; Z. U. Rahman

2006-01-01

83

Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents  

DOEpatents

A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known pressure swing adsorption'' technique utilizing the same sorption material. 1 fig.

Judkins, R.R.; Burchell, T.D.

1999-07-20

84

Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents  

DOEpatents

A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known "pressure swing adsorption" technique utilizing the same sorption material.

Judkins, Roddie R. (9917 Rainbow Dr., Knoxville, TN 37922); Burchell, Timothy D. (109 Greywood Pl., Oak Ridge, TN 37830)

1999-01-01

85

Emission factors for particles, elemental carbon, and trace gases from the Kuwait oil fires  

SciTech Connect

Emission factors are presented for particles, elemental carbon (i.e., soot), total organic carbon in particles and vapor, and for various trace gases from the 1991 Kuwait oil fires. Particle emissions accounted for {approximately} 2% of the fuel burned. In general, soot emission factors were substantially lower than those used in recent {open_quotes}nuclear winter{close_quotes} calculations. Differences in the emissions and appearances of some of the individual fires are discussed. Carbon budget data for the composite plumes from the Kuwait fires are summarized; most of the burned carbon in the plumes was in the form of CO{sub 2}. Fluxes are presented for several combustion products. 26 refs., 1 fig., 5 tabs.

Laursen, K.K.; Ferek, R.J.; Hobbs, P.V. [Univ. of Washington, Seattle, WA (United States); Rasmussen, R.A. [Oregon Graduate Institute of Science and Technology, Beaverton, OR (United States)

1992-09-20

86

Origins of natural gases from marine strata in Northeastern Sichuan Basin (China) from carbon molecular moieties and isotopic data  

NASA Astrophysics Data System (ADS)

To determine the origin, maturity, formation mechanism and secondary process of marine natural gases in Northeastern Sichuan area, molecular moieties and carbon isotopic data of the Carboniferous and Triassic gases have been analyzed. Typical samples of marine gas precursors including low-maturity kerogen, dispersed liquid hydrocarbons (DLHs) in source rocks, residual kerogen and oil have been examined in a closed system, and several published geochemical diagrams of gas origins have been calibrated by using laboratory data. Results show that both Carboniferous and Triassic gases in the study area have a thermogenic origin. Migration leads to stronger compositional and weak isotopic fractionation, and is path dependent. Carboniferous gases and low-H2S gases are mainly formed by secondary cracking of oil, whereas high-H2S gases are clearly related to the TSR (Thermal Sulfate Reduction) process. Gases in NE Sichuan show a mixture of heavy (13C-enriched) methane in comparison to the lower maturated ethane of Triassic gas samples, suggesting a similar source and maturity for ethane and propane of Carboniferous gases, and a mixture of heavy ethane to the propane for Triassic gases. Based on the data plotted in the diagram of Chung et al. (1988), the residual kerogen from Silurian marine shale and palaeo oil reservoirs are the main source for Carboniferous gases, and that the residual kerogen from Silurian and Permian marine rocks and Permian paleao oil reservoirs constitute the principal source of Triassic gases.

Wang, Yunpeng; Zhao, Changyi; Wang, Hongjun; Wang, Zhaoyun; Wang, Zecheng

2013-03-01

87

Soluble species in the Arctic summer troposphere - acidic gases, aerosols, and precipitation  

SciTech Connect

The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions. 61 refs.

Talbot, R.W.; Vijgen, A.S.; Harriss, R.C. (New Hampshire Univ., Durham (United States) Old Dominion Univ., Norfolk, VA (United States))

1992-10-01

88

Control of Effluent Gases from Solid Waste Processing using Impregnated Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

One of the major problems associated with solid waste processing technologies is effluent contaminants that are released in gaseous forms from the processes. This is a concern in both biological as well as physicochemical solid waste processing. Carbon dioxide (CO2), the major gas released, does not present a serious problem and there are currently in place a number of flight-qualified technologies for CO2 removal. However, a number of other gases, in particular NOx, SO2, NH3, and various hydrocarbons (e.g. CH4) do present health hazards to the crew members in space habitats. In the present configuration of solid waste processing in the International Space Station (ISS), some of these gases are removed by the Trace Contaminant Control System (TCCS), demands a major resupply. Reduction of the resupply can be effective by using catalyst impregnated carbon nanotubes. For example, NO decomposition to N2 and O2 is thermodynamically favored. Data showing decomposition of NO on metal impregnated carbon nanotubes is presented. Comparisons are made of the existing TCCS systems with the carbon nanotube based technology for removing NOx based on mass/energy penalties.

Li, Jing; Fisher, John; Wignarajah, Kanapathipillai

2005-01-01

89

High emissions of carbon gases from a boreal headwater stream network of Interior Alaska  

NASA Astrophysics Data System (ADS)

Small boreal streams integrate the signals of terrestrial and aquatic carbon cycling in their catchments. Recent evidence suggests that despite their limited coverage on the landscape, small streams play a significant role in the downstream delivery of carbon and the emission of trace carbon gases (methane and carbon dioxide) to the atmosphere. However, aquatic gas emissions have not been well documented in many parts of the boreal forest including interior Alaska. We measured carbon gas emissions from a headwater stream network in the Beaver Creek watershed, Yukon River basin, during May (spring thaw) to September, 2011 using discrete measurements and continuous monitoring of stream pCO2. Carbon dioxide emissions from all sites averaged >4.5 gC m-2 day-1, with small streams exhibiting the highest and most variable emission rates. All sites were supersaturated with CO2 for the entire open-water season. Methane emissions averaged >9.1 mgC m-2 day-1 with a maximum of ~37 mgC m-2 day-1 in a mostly burned catchment. Low water temperatures and short water residence times probably limit in-stream respiration and support the hypothesis that high pCO2 in these streams is derived from terrestrial respiration and groundwater sources. Lower pCO2 of larger streams is likely controlled by rapid outgassing in upstream reaches and poor hydrologic connectivity with portions of the surrounding landscape. Overall, these small upland streams are a constant source of trace gases to the atmosphere during the ice free season and exhibit much higher emission rates than most previously studied boreal stream networks. This reinforces the need for more complete characterization of the spatial and temporal patterns of stream C-gas emissions when assessing whole watershed carbon budgets.

Crawford, J. T.; Striegl, R. G.; Wickland, K. P.; Stanley, E. H.

2011-12-01

90

Raman Scattering Sensor for On-Line Monitoring of Amines and Acid Gases  

SciTech Connect

Sulfur and CO2 removal from hydrocarbon streams and power plant effluents are a major problem. The sulfur is normally in the form of H2S. These two acid gases are scrubbed using aqueous amine solutions that are difficult to control with conventional technology. Process Instruments Inc. developed Raman scattering technology for on-line, real-time monitoring of amine streams to improve their efficiency in scrubbing H2S and CO2 from hydrocarbon streams and power plant effluents. Improved control of amine and acid gas concentrations will allow refineries, natural gas processes and power plants to more efficiently scrub Sulfur and CO2, saving energy, time and financial resources.

Uibel, Rory; Smith, Lee

2010-05-20

91

Automatic Carbon Dioxide-Methane Gas Sensor Based on the Solubility of Gases in Water  

PubMed Central

Biogas methane content is a relevant variable in anaerobic digestion processing where knowledge of process kinetics or an early indicator of digester failure is needed. The contribution of this work is the development of a novel, simple and low cost automatic carbon dioxide-methane gas sensor based on the solubility of gases in water as the precursor of a sensor for biogas quality monitoring. The device described in this work was used for determining the composition of binary mixtures, such as carbon dioxide-methane, in the range of 0–100%. The design and implementation of a digital signal processor and control system into a low-cost Field Programmable Gate Array (FPGA) platform has permitted the successful application of data acquisition, data distribution and digital data processing, making the construction of a standalone carbon dioxide-methane gas sensor possible. PMID:23112626

Cadena-Pereda, Raúl O.; Rivera-Muñoz, Eric M.; Herrera-Ruiz, Gilberto; Gomez-Melendez, Domingo J.; Anaya-Rivera, Ely K.

2012-01-01

92

Utilization of carbon dioxide in industrial flue gases for the cultivation of microalga Chlorella sp.  

PubMed

The biomass and lipid productivity of Chlorella sp. MTF-15 cultivated using aeration with flue gases from a coke oven, hot stove or power plant in a steel plant of the China Steel Corporation in Taiwan were investigated. Using the flue gas from the coke oven, hot stove or power plant for cultivation, the microalgal strain obtained a maximum specific growth rate and lipid production of (0.827 d(-1), 0.688 g L(-1)), (0.762 d(-1), 0.961 g L(-1)), and (0.728 d(-1), 0.792 g L(-1)), respectively. This study demonstrated that Chlorella sp. MTF-15 could efficiently utilize the CO?, NOX and SO? present in the different flue gases. The results also showed that the growth potential, lipid production and fatty acid composition of the microalgal strain were dependent on the composition of the flue gas and on the operating strategy deployed. PMID:24950094

Kao, Chien-Ya; Chen, Tsai-Yu; Chang, Yu-Bin; Chiu, Tzai-Wen; Lin, Hsiun-Yu; Chen, Chun-Da; Chang, Jo-Shu; Lin, Chih-Sheng

2014-08-01

93

Stability of calcium carbonate and magnesium carbonate in rainwater and nitric acid solutions  

Microsoft Academic Search

Carbonation of magnesium and calcium silicates has emerged as an interesting option for long term storage of captured CO2. However, carbonated minerals are not stable in acidic environments. This study was conducted to determine if synthetically carbonated minerals dissolve in acidic rain and release CO2. Synthetic magnesium and calcium carbonates were leached in nitric acid solutions of various acidities, as

Sebastian Teir; Sanni Eloneva; Carl-Johan Fogelholm; Ron Zevenhoven

2006-01-01

94

Laboratory simulation of meteoritic noble gases. III - Sorption of neon, argon, krypton, and xenon on carbon - Elemental fractionation  

NASA Technical Reports Server (NTRS)

The sorption of Ne, Ar, Kr, and Xe was studied in carbon black, acridine carbon, and diamond in an attempt to understand the origin of trapped noble gases in meteorites. The results support a model in which gases are physically adsorbed on interior surfaces formed by a pore labyrinth within amorphous carbons. The data show that: (1) the adsorption/desorption times are controlled by choke points that restrict the movement of noble gas atoms within the pore labyrinth, and (2) the physical adsorption controls the temperature behavior and elemental fractionation patterns.

Wacker, John F.

1989-01-01

95

Impact of carbon dioxide, trace gases, and climate change on global agriculture  

SciTech Connect

Global climate change is one of several important issues that will command the attention of policymakers and scientist in the 1990s. The evidence that concentrations of carbon dioxide (CO{sub 2}), and other gases are increasing in the atmosphere is irrefutable. The evidence, and the knowledge that CO{sub 2} and trace gases may absorb thermal radiation sufficient to warm the atmosphere, has prompted much speculation that ensuing atmospheric warming may lead to changes in the distribution of precipitation, and of crop adaptation and productivity, that would alter the world supply of food and fiber. The implications of this speculation are compelling for agronomists, because agronomists are stewards of the world's food supply and of the natural resources that are used to produce food. Agronomists have a pivotal role in conducting the research needed to anticipate crop response to climate changes, and in informing policymakers and the general public about the adequacy of our knowledge. In this publication agronomists assess the current status of scientific knowledge about the putative role of greenhouse gases in global climate change and report their findings.

Not Available

1990-01-01

96

Analysis of Effluent Gases During the CCVD Growth of Multi Wall Carbon Nanotubes from Acetylene  

NASA Technical Reports Server (NTRS)

Catalytic chemical vapor deposition was used to grow multi-walled carbon nanotubes on a Fe:Co:CaCO3 catalyst from acetylene. The influent and effluent gases were analyzed by gas chromatography and mass spectrometry at different time intervals during the nanotubes growth process in order to better understand and optimize the overall reaction. A large number of byproducts were identified and it was found that the number and the level for some of the carbon byproducts significantly increased over time. The CaCO3 catalytic support thermally decomposed into CaO and CO2 resulting in a mixture of two catalysts for growing the nanotubes, which were found to have outer diameters belonging to two main groups 8 to 35 nm and 40 to 60 nm, respectively.

Schmitt, T. C.; Biris, A. S.; Miller, D. W.; Biris, A. R.; Lupu, D.; Trigwell, S.; Rahman, Z. U.

2005-01-01

97

Conductance isotherms for adsorption of noble gases on individual single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Using transistors made from suspended carbon nanotubes allows one to probe the interaction of adsorbed atoms and molecules with the carbon substrate electrons. We have studied the effects of adsorbing He, Ne, Ar, Kr, Xe, and other gases on the electrical properties of individual suspended single-walled nanotubes, as a function of pressure and temperature. The conductance changes measurably, and sometimes dramatically, as a monolayer forms and undergoes phase transitions. It yields complementary information to the coverage, which is obtained from the mass shift in the natural vibrational frequency of the nanotube. For example, measurements below the 2D critical point show nonmonotonic features and fluctuations heralding the first-order phase transition. Conductance changes can be measured on a timescale of milliseconds, permitting studies of the dynamics of the monolayer. In the nonlinear regime we observe features in the I-V characteristics as phase transitions are induced by the current and nonequilibrium stationary states occur.

Dzyubenko, Boris; Lee, Hao-Chun; Vilches, Oscar; Cobden, David

2012-02-01

98

Laboratory simulation of meteoritic noble gases. I - Sorption of xenon on carbon: Trapping experiments  

NASA Technical Reports Server (NTRS)

The sorption of Xe-127 at 5 x 10 to the -7th atm onto carbon black, pyrolyzed polyvinylidene chloride, and pyrolyzed acridine at 100-1000 C for 5 min-240 h is measured experimentally by gamma spectrometry. The results are presented in tables and graphs and characterized in detail. The tightly bound Xe remaining in the samples after 4000 min pumping at temperatures above 100 C is found to comprise two components: a low-temperature component attributed to physisorption within an atomic-scale labyrinth of micropores, and a high-temperature component due to volume diffusion. The implications for the trapping of noble gases near grain surfaces of amorphous carbon in meteorites are considered.

Wacker, J. F.; Zadnik, M. G.; Anders, E.

1985-01-01

99

Biogeochemical cycling of carbon, water, energy, trace gases, and aerosols in Amazonia: The LBA-EUSTACH experiments  

Microsoft Academic Search

The biogeochemical cycling of carbon, water, energy, aerosols, and trace gases in the Amazon Basin was investigated in the project European Studies on Trace Gases and Atmospheric Chemistry as a Contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA-EUSTACH). We present an overview of the design of the project, the measurement sites and methods, and the meteorological conditions during the

M. O. Andreae; P. Artaxo; C. Brandão; F. E. Carswell; P. Ciccioli; A. L. da Costa; A. D. Culf; J. L. Esteves; J. H. C. Gash; J. Grace; P. Kabat; J. Lelieveld; Y. Malhi; A. O. Manzi; F. X. Meixner; A. D. Nobre; C. A. Nobre; M. d. L. P. Ruivo; M. A. F. da Silva-Dias; P. Stefani; R. Valentini; J. von Jouanne; M. J. Waterloo

2002-01-01

100

Blood gases  

MedlinePLUS

Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine ... taking a sample of blood from the wrist area. The health care provider will insert a small ...

101

Study of Acid Response of Qatar Carbonate Rocks  

E-print Network

reservoirs. Recently papers published from industry discussed the techniques, planning, and optimization of acid stimulation for Qatar carbonate. To the best of author’s knowledge, no study has focused on the acid reaction to Qatar carbonates. The lack...

Wang, Zhaohong

2012-02-14

102

Lower mantle contribution to the genesis of carbonatites: the noble gases and carbon isotopic evidence  

NASA Astrophysics Data System (ADS)

It has been demonstrated that only 20 to 40% of the subducted CO2 is extracted by decarbonatation of descending slab. This, and the fact that some carbonatites exhibit HIMU-like Pb, Nd and Sr isotopic signatures, led to models invoking a carbonatite origin by partial melting of ancient subducted carbonated oceanic crust. A recycled carbon origin for diamonds has also been suggested. However the mantle is the largest carbon reservoir of the Earth and a non-recycled (i.e. primordial) origin for the carbon in carbonatites cannot be discarded. Some of the Cape Verde oceanic carbonatites present low 4He/3He ratios (down to 46,700; R/Ra up to 15.5) demonstrating that they sample a reservoir characterized by low time-integrated (U+Th)/3He. Such a reservoir, being clearly distinct from the crust or from the upper mantle sampled by the 60 000 km long oceanic ridge system, is thought to be localized in the lower mantle. For continental carbonatites several authors has also interpreted noble gases isotopic compositions as reflecting the contribution of a reservoir with time-integrated (U+Th)/(3He, 22Ne) and 40K/36Ar lower than the upper mantle, thus endorsing the contribution of the lower mantle [1;2;3]. Some carbonatites are also characterized by 129Xe anomalies relatively to the air (129Xe/130Xe up to 6.94 in Cape Verde). Considering that the recycling of carbonates, eventually characterized by high Te and Ba contents, would with time increase simultaneously the 129Xe and 130Xe, the observed 129Xe anomalies cannot be explained by models calling upon crustal carbonate recycling. We interpret them in terms of an ancient mantle origin by decay of the now extinct 129I. Moreover, experimental work has demonstrated that crustal carbonates are unlikely to be transported to lower mantle depth levels as a consequence of its removal by melting reactions. Thus, all the above described lower mantle signals are indicative of a non-recycled, lower mantle, origin for carbon, unless we admit that, during ascent, deep-seated mantle plumes entrain recycled carbon from the upper mantle. Nevertheless many carbonatites are also characterized by ^13C values (-8.0 to -4.25 per mil in Cape Verde) lighter than those characterizing crustal inorganic carbonates, endorsing the role of primordial carbon to the genesis of carbonatites. Taking into account that a recycled origin for some carbonatites is inescapable from carbon and noble gases signatures [e.g. 4; 5] we conclude that multiple origins (recycled vs. primordial) are possible for the carbon involved in the generation of carbonatitic magmas. Sasada et al. (1997) - Geochim. Cosmochim. Acta, 61: 4219-4228 Marty et al. (1998)- Earth Planet. Sci. Lett., 164: 179-192 Tolstikhin et al. (2002) - Geochim. Cosmochim. Acta, 66: 881-901 Ray et al. (1999) - Earth Planet Sci. Lett., 170; 205-214 Basu & Murty (2006) - Chem. Geol., 234: 236-250 This is a contribution from the FCT/FEDER project PLINT (POCTI/CTA/45802/2002)

Mata, J.; Moreira, M.; Mourão, C.; Ader, M.; Doucelance, R.

2009-04-01

103

Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases  

DOEpatents

Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

Wijmans, Johannes G. (Menlo Park, CA); Merkel, Timothy C (Menlo Park, CA); Baker, Richard W. (Palo Alto, CA)

2011-10-11

104

Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases.  

PubMed

The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay. PMID:23907148

Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

2013-01-01

105

Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases  

PubMed Central

The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay. PMID:23907148

Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

2013-01-01

106

Biological production of products from waste gases  

DOEpatents

A method and apparatus are designed for converting waste gases from industrial processes such as oil refining, and carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various products, such as organic acids, alcohols, hydrogen, single cell protein, and salts of organic acids by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified.

Gaddy, James L. (Fayetteville, AR)

2002-01-22

107

Water-responsive carbon nanotubes for selective detection of toxic gases  

NASA Astrophysics Data System (ADS)

Ammonia plays an important role in our daily lives and hence its quantitative and qualitative sensing has become necessary. Bulk structure of carbon nanotubes (CNTs) has been employed to detect the gas concentration of 10 ppm. Hydrophobic CNTs were turned to hydrophilic via the application of a ramp electric field that allowed confinement of a controlled amount of water inside CNT microstructure. These samples were then also used to detect different gases. A comparative study has been performed for sensing three reducing gases, namely, ammonia, sulphur-di-oxide, and hydrogen sulphide to elaborate the selectivity of the sensor. A considerable structural bending in the bulk CNT was observed on evaporation of the confined water, which can be accounted to the zipping of individual nanotubes. However, the rate of the stress induced on these bulk microstructures increased on the exposure of ammonia due to the change in the surface tension of the confined solvent. A prototype of an alarm system has been developed to illustrate sensing concept, wherein the generated stress in the bulk CNT induces a reversible loss in electrical contact that changes the equivalent resistance of the electrical circuit upon exposure to the gas.

Mukherjee, Soumalya; Sakorikar, Tushar; Mukherjee, Anwesha; Misra, Abha

2015-03-01

108

Greenhouse gases, climate change and the transition from coal to low-carbon electricity  

NASA Astrophysics Data System (ADS)

A transition from the global system of coal-based electricity generation to low-greenhouse-gas-emission energy technologies is required to mitigate climate change in the long term. The use of current infrastructure to build this new low-emission system necessitates additional emissions of greenhouse gases, and the coal-based infrastructure will continue to emit substantial amounts of greenhouse gases as it is phased out. Furthermore, ocean thermal inertia delays the climate benefits of emissions reductions. By constructing a quantitative model of energy system transitions that includes life-cycle emissions and the central physics of greenhouse warming, we estimate the global warming expected to occur as a result of build-outs of new energy technologies ranging from 100 GWe to 10 TWe in size and 1-100 yr in duration. We show that rapid deployment of low-emission energy systems can do little to diminish the climate impacts in the first half of this century. Conservation, wind, solar, nuclear power, and possibly carbon capture and storage appear to be able to achieve substantial climate benefits in the second half of this century; however, natural gas cannot.

Myhrvold, N. P.; Caldeira, K.

2012-03-01

109

Adsorption studies of simple gases on As-produced single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Adsorption isotherms measurements were used to study films of Xenon (Xe), Argon (Ar), Methane (CH4), Hydrogen (H2) and Neon (Ne) adsorbed on bundles of as-produced Single Walled Carbon Nanotubes (SWNT). A comparison of the specific surface areas of the SWNT samples measured with these various gases, as well as a comparison of the binding energies measured for each of them on the SWNT bundles; allows us to infer which of the possible groups of adsorption sites on the SWNT bundles are actually occupied by the adsorbed gases. The presence of substeps in the first layer isotherm data establishes the existence of different phases within the first layer film. A detailed comparison of our experimental results to recent computer simulations for these systems is done. This allows us to determine the nature of the phases present in the first layer. Evidence of the formation of a one-dimensional phase in the second layer film (i.e. the film that forms after the entire surface of the bundles is covered by one layer of gas) is observed in these studies. The sharpness of this second layer feature varies as a function of the molecular diameter of the adsorbate.

Talapatra, Saikat

110

Experimental High Velocity Acid Jetting in Limestone Carbonates  

E-print Network

Acid jetting is a well stimulation technique that is used in carbonate reservoirs. It typically involves injecting acid down hole at high flow rates through small orifices which cause high velocities of acid to strike the borehole wall...

Holland, Christopher

2014-04-30

111

Carbon Dioxide Separation from Flue Gases: A Technological Review Emphasizing Reduction in Greenhouse Gas Emissions  

PubMed Central

Increasing concentrations of greenhouse gases (GHGs) such as CO2 in the atmosphere is a global warming. Human activities are a major cause of increased CO2 concentration in atmosphere, as in recent decade, two-third of greenhouse effect was caused by human activities. Carbon capture and storage (CCS) is a major strategy that can be used to reduce GHGs emission. There are three methods for CCS: pre-combustion capture, oxy-fuel process, and post-combustion capture. Among them, post-combustion capture is the most important one because it offers flexibility and it can be easily added to the operational units. Various technologies are used for CO2 capture, some of them include: absorption, adsorption, cryogenic distillation, and membrane separation. In this paper, various technologies for post-combustion are compared and the best condition for using each technology is identified. PMID:24696663

Songolzadeh, Mohammad; Soleimani, Mansooreh; Takht Ravanchi, Maryam; Songolzadeh, Reza

2014-01-01

112

Foliage plants for indoor removal of the primary combustion gases carbon monoxide and nitrogen dioxide  

NASA Technical Reports Server (NTRS)

Foliage plants were evaluated for their ability to sorb carbon monoxide and nitrogen dioxide, the two primary gases produced during the combustion of fossil fuels and tobacco. The spider plant (Chlorophytum elatum var. vittatum) could sorb 2.86 micrograms CO/sq cm leaf surface in a 6 h photoperiod. The golden pothos (Scindapsus aureus) sorbed 0.98 micrograms CO/sq cm leaf surface in the same time period. In a system with the spider plant, greater than or equal to 99 percent of an initial concentration of 47 ppm NO2 could be removed in 6 h from a void volume of approximately 0.35 cu m. One spider plant potted in a 3.8 liter container can sorb 3300 micrograms CO and effect the removal of 8500 micrograms NO2/hour, recognizing the fact that a significant fraction of NO2 at high concentrations will be lost by surface sorption, dissolving in moisture, etc.

Wolverton, B. C.; Mcdonald, R. C.; Mesick, H. H.

1985-01-01

113

Carbon dioxide separation from flue gases: a technological review emphasizing reduction in greenhouse gas emissions.  

PubMed

Increasing concentrations of greenhouse gases (GHGs) such as CO2 in the atmosphere is a global warming. Human activities are a major cause of increased CO2 concentration in atmosphere, as in recent decade, two-third of greenhouse effect was caused by human activities. Carbon capture and storage (CCS) is a major strategy that can be used to reduce GHGs emission. There are three methods for CCS: pre-combustion capture, oxy-fuel process, and post-combustion capture. Among them, post-combustion capture is the most important one because it offers flexibility and it can be easily added to the operational units. Various technologies are used for CO2 capture, some of them include: absorption, adsorption, cryogenic distillation, and membrane separation. In this paper, various technologies for post-combustion are compared and the best condition for using each technology is identified. PMID:24696663

Songolzadeh, Mohammad; Soleimani, Mansooreh; Takht Ravanchi, Maryam; Songolzadeh, Reza

2014-01-01

114

Real-time trace-level detection of carbon dioxide and ethylene in car exhaust gases  

NASA Astrophysics Data System (ADS)

A direct-absorption spectrometer, based on a pulsed, distributed feedback, quantum cascade laser with a 10.26-?m wavelength and an astigmatic Herriott cell with a 66-m path length, has been developed for high-resolution IR spectroscopy. This spectrometer utilizes the intrapulse method, an example of sweep integration, in which the almost linear wavelength up-chirp obtained from a distributed feedback, quantum cascade laser yields a spectral microwindow of as many as 2.5 wave numbers/cm^-1. Within this spectral microwindow, molecular fingerprints can be monitored and recorded in real time. This system allows both the detection of carbon dioxide and ethylene and the real-time observation of the evolution of these gases in the exhaust by-products from several cars.

McCulloch, Michael T.; Langford, Nigel; Duxbury, Geoffrey

2005-05-01

115

Recycling and fluxes of carbon gases in a stratified boreal lake following experimental carbon addition  

NASA Astrophysics Data System (ADS)

Partly anoxic stratified humic lakes are important sources of methane (CH4) and carbon dioxide (CO2) to the atmosphere. We followed the fate of CH4 and CO2 in a small boreal stratified lake, Alinen Mustajärvi, during 2007-2009. In 2008 and 2009 the lake received additions of dissolved organic carbon (DOC) with stable carbon isotope ratio (?13C) around 16‰ higher than that of local allochthonous DOC. Carbon transformations in the water column were studied by measurements of ?13C of CH4 and of the dissolved inorganic carbon (DIC). Furthermore, CH4 and CO2 production, consumption and emissions were estimated. Methane oxidation was estimated by a diffusion gradient method. The amount, location and ?13C of CH4-derived biomass and CO2 in the water column were estimated from the CH4 oxidation pattern and from measured ?13C of CH4. Release of CH4 and CO2 to the atmosphere increased during the study. Methane production and almost total consumption of CH4 mostly in the anoxic water layers, was equivalent to the input from primary production (PP). ?13C of CH4 and DIC showed that hydrogenotrophic methanogenesis was the main source of CH4 to the water column, and methanogenic processes in general were the reasons for the 13C-enriched DIC at the lake bottom. CH4 and DIC became further 13C-enriched in the anoxic layer of the water column during the years of DOC addition. Even gradient diffusion measurements showed active CH4 oxidation in the anoxic portion of the water column; there was no clear 13C-enrichment of CH4 as generally used to estimate CH4 oxidation strength. Increase in ?13C-CH4 was clear between the metalimnion and epilimnion where the concentration of dissolved CH4 and the oxidation of CH4 were small. Thus, 13C-enrichment of CH4 does not reveal the main location of methanotrophy in a lake having simultaneous anaerobic and aerobic oxidation of CH4. Overall the results show that organic carbon is processed efficiently to CH4 and CO2 and recycled in the anoxic layer of stratified boreal lakes by CH4 oxidation. In spite of this, increased DOC input led to increased greenhouse gas release, mainly as CO2 but also as CH4. Due to the predominantly anaerobic CH4 oxidation, a relatively small amount of CH4-derived biomass was produced, while a large amount of CH4-derived CO2 was produced in the anoxic bottom zone of the lake.

Nykänen, H.; Peura, S.; Kankaala, P.; Jones, R. I.

2014-11-01

116

Carbon Dioxide Information Analysis Center and World Data Center for Atmospheric Trace Gases, Fiscal Year 2002 Annual Report  

SciTech Connect

The Carbon Dioxide Information Analysis Center (CDIAC), which includes the World Data Center (WDC) for Atmospheric Trace Gases, is the primary global change data and information analysis center of the U.S. Department of Energy (DOE). More than just an archive of data sets and publications, CDIAC has, since its inception in 1982, enhanced the value of its holdings through intensive quality assurance, documentation, and integration. Whereas many traditional data centers are discipline-based (for example, meteorology or oceanography), CDIAC's scope includes potentially anything and everything that would be of value to users concerned with the greenhouse effect and global climate change, including atmospheric concentrations and atmospheric emissions of carbon dioxide (CO{sub 2}) and other radiatively active gases; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; long-term climate trends; the effects of elevated CO{sub 2} on vegetation; and the vulnerability of coastal areas to rising sea levels.

Cushman, R.M.

2003-08-28

117

Carbon dioxide Information Analysis Center and World Data Center: A for Atmospheric trace gases. Annual progress report, FY 1994  

SciTech Connect

This report summarizes the activities and accomplishments made by the Carbon Dioxide Information Analysis Center and World Data Center-A for Atmospheric Trace Gases during the fiscal year 1994. Topics discussed in this report include; organization and staff, user services, systems, communications, Collaborative efforts with China, networking, ocean data and activities of the World Data Center-A.

Burtis, M.D. [comp.] [Tennessee Univ., Knoxville, TN (United States). Energy, Environment and Resources Center; Cushman, R.M.; Boden, T.A.; Jones, S.B.; Nelson, T.R.; Stoss, F.W. [Oak Ridge National Lab., TN (United States)

1995-03-01

118

Oceanic Trace Gases Numeric Data Packages from the Carbon Dioxide Information Analysis Center (CDIAC)  

DOE Data Explorer

CDIAC products include numeric data packages, publications, trend data, atlases, models, etc. and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Most data sets or packages, many with numerous data files, are free to download from CDIAC's ftp area. CDIAC lists the following numeric data packages under the broad heading of Oceanic Trace Gases: Carbon Dioxide, Hydrographic, and Chemical Data Obtained during the R/V Ronald H. Brown Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO2 Section A16S_2005 ( 01/11/05 - 022405) • Determination of Carbon Dioxide, Hydrographic, and Chemical Parameters during the R/V Nathaniel B. Palmer Cruise in the Southern Indian Ocean (WOCE Section S04I, 050396 - 070496) • Inorganic Carbon, Nutrient, and Oxygen Data from the R/V Ronald H. Brown Repeat Hydrography Cruise in the Atlantic Ocean: CLIVAR CO2 Section A16N_2003a (060403 – 081103) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Maurice Ewing Cruise in the Atlantic Ocean (WOCE Section A17, 010494 - 032194) • Global Ocean Data Analysis Project GLODAP: Results and Data • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Knorr Cruises in the North Atlantic Ocean on WOCE Sections AR24 (1102 – 120596) and A24, A20, and A22 (053097 – 090397) • Carbon Dioxide, Hydrographic and Chemical Data Obtained During the Nine R/V Knorr Cruises Comprising the Indian Ocean CO2 Survey (WOCE Sections I8SI9S, I9N, I8NI5E, I3, I5WI4, I7N, I1, I10, and I2; 120 194 – 012296) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Meteor Cruise 28/1 in the South Atlantic Ocean (WOCE Section A8, 032994 - 051294) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Knorr Cruise 138-3, -4, and -5 in the South Pacific Ocean (WOCE Sections P6E, P6C, and P6W, 050292 - 073092) • Global Distribution of Total Inorganic Carbon and Total Alkalinity below the deepest winter mixed layer depths • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V John V. Vickers Cruise in the Pacific Ocean (WOCE Section P13, NOAA CGC92 Cruise, 080492 – 102192) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Hesperides Cruise in the Atlantic Ocean (WOCE Section A5, 071492 - 081592) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Thomas G. Thompson Cruise in the Pacific Ocean (WOCE Section P10, 100593 – 111093) • The International Intercomparison Exercise of Underway fCO2 Systems during the R/V Meteor Cruise 36/1 in the North Atlantic Ocean • Carbon Dioxide, Hydrographic, and Chemical Data Obtained during the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (WOCE Section A10, Dec. 1992-Jan, 1993) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained in the South Pacific Ocean (WOCE Sections P16A/P17A, P17E/P19S, and P19C, R/V Knorr , Oct. 1992-April 1993) • Surface Water and Atmospheric Underway Carbon Data Obtained During the World Ocean Circulation Experiment Indian Ocean Survey Cruises (R/V Knorr, Dec. 1994 – Jan, 1996) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Akademik Ioffe Cruise in the South Pacific Ocean (WOCE Section S4P, Feb.-April 1992) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Thomas Washington Cruise TUNES-1 in the Equatorial Pacific Ocean (WOCE section P17C) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Thomas Washington Cruise TUNES-3 in the Equatorial Pacific Ocean (WOCE section P16C) • Carbon-14 Measurements in Surface Water CO2 from the Atlantic, Indian and Pacific Oceans, 1965-1994 • Carbon Dioxide, Hydrographic, and Chemical Data Obtained During R/V Meteor Cruise 18/1 in the North Atlantic Ocean (WOCE Section A1E) • Carbon Dioxide, Hydrographic, and Chemical Data Obtained in the Central South Pacific Ocean (WOCE Sections P17S and P16S) during the TUNES-2 Expedition of the R/V Th

119

One-step synthesis of novel sulfuric acid groups' functionalized carbon via hydrothermal carbonization  

Microsoft Academic Search

The novel sulfuric acid groups' functionalized carbon has been synthesized via one-step hydrothermal carbonization of polyvinyl alcohol and hydroxyethylsulfuric acid. The novel carbon exhibited high acidity and comparable activities to sulfonic acid for the traditional acid-catalyzed reactions, which indicated that it has great potential for the environmental-friendly processes. The copolymerization method provides an efficient procedure for the synthesis of various

Xuezheng Liang; Huiquan Xiao; Yongmiao Shen; Chenze Qi

2010-01-01

120

One-step synthesis of carbon functionalized with sulfonic acid groups using hydrothermal carbonization  

Microsoft Academic Search

Carbon functionalized with sulfonic acid groups has been synthesized using the one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid aqueous solution at 180°C for 4h. The carbon exhibited high acidity and comparable activities to sulfuric acid for the traditional acid-catalyzed reactions, which indicated that it has great potential for environment-friendly processes. The copolymerization method provides an efficient procedure for the

Xuezheng Liang; Minfeng Zeng; Chenze Qi

2010-01-01

121

Emission characteristics and control efficiency of acidic and basic gases and aerosols from packed towers  

NASA Astrophysics Data System (ADS)

Large amount of acidic liquids, such as H 2SO 4, HF, HCl and HNO 3, and basic NH 3 liquid are used in high-tech industries in cleaning and etching processes in the Hsinchu Science-Based Industrial Park in Taiwan. The industries use packed towers (or scrubbers) to control emission of these inorganic pollutants, in which acidic gases but not particles are regulated by the Taiwan EPA's strict emission standard for semiconductor industry. To understand whether the emission standard is met and to investigate the emission rates, emission profiles, emission factors, and control efficiencies of various gaseous/aerosol species, measurement of pollutants before and after the packed towers was conducted using a sensitive porous metal sampler during January 2001 to February 2003. Results show that the pollutants are mainly in the gaseous phase, and the control efficiency of pollutants is low and variable when the inlet concentration is low. In addition to the control efficiency data, emission factors before the control device for various gas and particle species have also been developed for estimating the emission rates.

Tsai, Chuen-Jinn; Chang, Chang-Tso; Liu, Tsing-Wei; Huang, Chun-Chao; Chien, Chih-Liang; Chein, Hung Min

122

Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes  

PubMed Central

Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas. PMID:23286690

2013-01-01

123

Isotope composition of carbon in amino acids of solid bitumens  

NASA Astrophysics Data System (ADS)

Primary data are presented on the isotope composition of carbon in individual amino acids from solid bitumens and several biological objects. The amino acids of biological objects are characterized by wide variations of the isotope composition of carbon. This fact occurs owing to the difference in biochemical paths of metabolism resulting in the synthesis of individual amino acids. The ?13C values are somewhat decreased for individual amino acids in asphaltenes, varying from -7.7 to -31.7‰. The carbon of amino acids is weighted in kerits from Bad'el' compared to asphaltenes. All the natural bitumens retain the characteristic trend for natural substances: the isotopically heavy and light amino acids by carbon are glycine and leucine, respectively. The isotope composition of amino-acid carbon is lightened compared to natural bitumens in the samples formed under a pronounced thermal impact (asphalt-like crust and kirishite).

Shanina, S. N.; Bushnev, D. A.

2014-06-01

124

Synthesis of a Novel Carbon Based Strong Acid Catalyst Through Hydrothermal Carbonization  

Microsoft Academic Search

A novel carbon based strong acid catalyst has been synthesized through the sulfonation of the carbon materials from glucose.\\u000a The novel acid catalyst was obtained through the hydrothermal carbonization instead of the traditional heat treatment, which\\u000a made the carbonization process under much milder condition with higher yield. The novel heterogeneous catalyst owned the advantages\\u000a of high acidity as much as

Xuezheng Liang; Jianguo Yang

2009-01-01

125

The Perils of Carbonic Acid and Equilibrium Constants.  

ERIC Educational Resources Information Center

Discusses the effects caused by small amounts of carbon dioxide usually present in water and acid-base equilibria of dilute solutions. Notes that dilute solutions of most weak acids and bases undergo significant dissociation or protonation. (MVL)

Jencks, William P.; Altura, Rachel A.

1988-01-01

126

High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.  

PubMed

The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential role of the dolomitic sorbent in enhancing the electric energy production efficiency of the plant, thanks to the better cleaning of the heat exchange surface that can be achieved. If such improvement is accounted for, all the potential impacts are considerably decreased (e.g. the Climate change by 28%), and in the comparison with the traditional operation 17 impact categories out of 19 are reduced. PMID:25465510

Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

2015-01-01

127

Functionalized carbon nanofibers as solid-acid catalysts for transesterification.  

PubMed

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient catalyst for the transesterification of triolein and methanol, outperforming conventional sulfonated carbons in both stability and activity per acid site. Upon comparing CNFs with varying degrees of functionalization, a linear correlation between sulfonic acid sites and catalytic performance was found. PMID:23908100

Stellwagen, Daniel R; van der Klis, Frits; van Es, Daan S; de Jong, Krijn P; Bitter, Johannes H

2013-09-01

128

Atmospheric Pollutants and Trace Gases Effects of Smelter Sulfur Dioxide Emissions: A Spatiotemporal Perspective Using Carbon Isotopes in Tree Rings  

Microsoft Academic Search

Most reports on tree-ring 13 C values address physiologi- cal questions, paleoclimatic records (e.g., Farquhar et We wanted to test the hypothesis that forest exposure to phytotoxic al., 1989; Lipp et al., 1996), or higher atmospheric CO2 gases indirectly affects their carbon uptake. We estimated that the concentration effects on tree growth (e.g., Bert et al., reduction of photosynthesis may

Martine M. Savard; Christian Begin; Michel Parent; Anna Smirnoff; Joelle Marion

129

Annular denuders for use in global climate and stratospheric measurements of acidic gases and particles  

NASA Technical Reports Server (NTRS)

Measurements of acidic and basic gases that coexist with fine particle (less than 2.5 micron) may be useful for determining the impact of these species on global climate changes and determining species that influence stratospheric ozone levels. Annular denuders are well suited for this purpose. A new concentric annular denuder system, consisting of a three channel denuder, a Teflon coated cyclone preseparator, and a multistage filter pack was developed, evaluated, and shown to provide reliable atmospheric measurements of SO2, HNO2, HNO3, NH3, SO4(=), NH4(+), NO3(-), and H(+). For example, the precision of the annular denuder for the ambient measurements of HNO3 and nitrates at concentrations between 0.1 to 3 microgram/cu m was + or - 12 and 16 pct., respectively. The 120 x 25 mm three channel denuder is encased in a stainless steel sheath and has annular spaces that are 1 mm wide. This design was shown to have nearly identical capacity for removal of SO2 as conventional 210 x 25 mm single channel denuder configurations. The cyclone preseparator was designed and tested to have a D sub 50 cutoff diameter of 2.5 micron and minimal retention of HNO3.

Stevens, Robert K.

1991-01-01

130

Impact of oxy-fuel combustion gases on mercury retention in activated carbons from a macroalgae waste: Effect of water.  

PubMed

The aim of this study is to understand the different sorption behaviors of mercury species on activated carbons in the oxy-fuel combustion of coal and the effect of high quantities of water vapor on the retention process. The work evaluates the interactions between the mercury species and a series of activated carbons prepared from a macroalgae waste (algae meal) from the agar-agar industry in oxy-combustion atmospheres, focussing on the role that the high concentration of water in the flue gases plays in mercury retention. Two novel aspects are considered in this work (i) the impact of oxy-combustion gases on the retention of mercury by activated carbons and (ii) the performance of activated carbons prepared from biomass algae wastes for this application. The results obtained at laboratory scale indicate that the effect of the chemical and textural characteristics of the activated carbons on mercury capture is not as important as that of reactive gases, such as the SOx and water vapor present in the flue gas. Mercury retention was found to be much lower in the oxy-combustion atmosphere than in the O2+N2 (12.6% O2) atmosphere. However, the oxidation of elemental mercury (Hg(0)) to form oxidized mercury (Hg(2+)) amounted to 60%, resulting in an enhancement of mercury retention in the flue gas desulfurization units and a reduction in the amalgamation of Hg(0) in the CO2 compression unit. This result is of considerable importance for the development of technologies based on activated carbon sorbents for mercury control in oxy-combustion processes. PMID:25585865

Lopez-Anton, M A; Ferrera-Lorenzo, N; Fuente, E; Díaz-Somoano, M; Suarez-Ruíz, I; Martínez-Tarazona, M R; Ruiz, B

2015-04-01

131

Low to middle tropospheric profiles and biosphere/troposphere fluxes of acidic gases in the summertime Canadian taiga  

NASA Technical Reports Server (NTRS)

We report features of acidic gases in the troposphere from 9 to 5000 m altitude above ground over the Canadian taiga in the summer of 1990. The measurements were conducted at a 30-m meteorological tower and from the NASA Wallops Electra aircraft as part of the joint U.S.-Canadian Arctic Boundary Layer Expedition (ABLE) 3B Northern Wetland Studies (NOWES). We sampled air for acidic gases using the mist chamber collector coupled with subsequent analysis using ion chromatography. At the tower we collected samples at two heights during a 13-day period, including diurnal studies. Using eddy flux and profile data, we estimated the biosphere/troposphere fluxes of nitric, formic, and acetic acids and sulfur dioxide. For the organic acids, emissions from the taiga in the afternoon hours and deposition during the predawn morning hours were observed. The flux intensities alone were however not high enough to explain the observed changes in mixing ratios. The measured deposition fluxes of nitric acid were high enough to have a significant influence on its mixing ratio in the boundary layer. On three days we measured vertical profiles of nitric, formic, and acetic acids through the lower to midtroposphere. We found that the chemical composition of the troposphere was extremely heterogenous. Pronounced layers of polluted air were readily apparent from our measurements. Local photochemical production and episodic long-range transport of trace components, originating from biomass burning and possibly industrial emissions, appear to have a strong influence on the composition of the troposphere and biosphere/troposphere fluxes of acidic gases at this site.

Klemm, O.; Talbot, R. W.; Fitzgerald, D. R.; Klemm, K. I.; Lefer, B. L.

1994-01-01

132

USE OF FATTY ACID STABLE CARBON ISOTOPE RATIO TO INDICATE MICROBIAL CARBON SOURCE IN TROPICAL SOILS  

EPA Science Inventory

We use measurements of the concentration and stable carbon isotope ratio of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels, broad microbial community structure, and microbial carbon source. For studies of soil o...

133

Surface modification of precipitated calcium carbonate using aqueous fluosilicic acid  

Microsoft Academic Search

Surface modification of calcium carbonate using aqueous fluosilicic acid (H2SiF6) was carried out in terms of the mole ratio of fluosilicic acid to calcium carbonate as well contact time. The resulting surface compounds of amorphous silica and calcium fluoride after surface modification were visualized on the surface of calcium carbonate. Amorphous silica was generated by the hydrolysis of silicon hexafluoride

Do Su Kim; Churl Kyoung Lee

2002-01-01

134

Hybrid Crystals of Calcium Carbonate and Amino Acids  

Microsoft Academic Search

We have investigated the effects of amino acids on the crystallization of calcium carbonate (CaCO3), and the reactivity between amino acids and CaCO3. Noncharged-polar and acidic amino acids are highly incorporated into CaCO3 and stabilize cauliflower-like grains composed of vaterite which is thermodynamically unstable in the CaCO3 polymorphs. Amino acids in the hybrid CaCO3 form radicals different from those in

Ayako Kai; Toshikatsu Miki

2000-01-01

135

High temperature abatement of acid gases from waste incineration. Part I: Experimental tests in full scale plants.  

PubMed

In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants. PMID:25465511

Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

2015-02-01

136

Acid Rain  

NSDL National Science Digital Library

Due to the presence of dissolved gases such as carbon dioxide, rainfall is naturally acidic. The release of other gases and chemicals such as sulfur dioxide during the combustion of coal and oil can cause rainfall to become even more acidic, sometimes to the point of toxicity. In this activity, students will measure the pH of local rainfall to see what effect these gases have in their region. They will also check an online resource to see how the releases of acid rain-causing chemicals have varied over the past 20 years, and answer questions about the information they uncover.

Chris Fox

137

Comparison of Carbonate and Uricase-Carbonate Methods for the Determination of Uric Acid in Serum  

Microsoft Academic Search

A colorimetric carbonate procedure for the determination of uric acid has been modi- fied to include incubation of serum with uricase to destroy uric acid. Residual non- urate chromogens are subtracted from total chromogens to obtain the concentration of \\

Wendell T. Caraway; Herman Marable

1965-01-01

138

Nitric acid vapor removal by activated, impregnated carbons  

Microsoft Academic Search

Laboratory and industrial workers can be exposed to vapors of nitric acid, especially in accidents, such as spills. Nitric acid can also be a product of incineration for energy production or waste (e.g., CW agent) disposal. Activated carbons containing impregnants for enhancing vapor and gas removal have been tested for effectiveness in removing vapors of nitric acid from air. The

Wood

1996-01-01

139

The origins and concentrations of water, carbon, nitrogen and noble gases on Earth  

NASA Astrophysics Data System (ADS)

The isotopic compositions of terrestrial hydrogen and nitrogen are clearly different from those of the nebular gas from which the solar system formed, and also differ from most of cometary values. Terrestrial N and H isotopic compositions are in the range of values characterizing primitive meteorites, which suggests that water, nitrogen, and other volatile elements on Earth originated from a cosmochemical reservoir that also sourced the parent bodies of primitive meteorites. Remnants of the proto-solar nebula (PSN) are still present in the mantle, presumably signing the sequestration of PSN gas at an early stage of planetary growth. The contribution of cometary volatiles appears limited to a few percents at most of the total volatile inventory of the Earth. The isotope signatures of H, N, Ne and Ar can be explained by mixing between two end-members of solar and chondritic compositions, respectively, and do not require isotopic fractionation during hydrodynamic escape of an early atmosphere. The terrestrial inventory of 40Ar (produced by the decay of 40K throughout the Earth's history) suggests that a significant fraction of radiogenic argon may be still trapped in the silicate Earth. By normalizing other volatile element abundances to this isotope, it is proposed that the Earth is not as volatile-poor as previously thought. Our planet may indeed contain up to ~ 3000 ppm water (preferred range: 1000-3000 ppm), and up to ~ 500 ppm C, both largely sequestrated in the solid Earth. This volatile content is equivalent to an ~ 2 (± 1) % contribution of carbonaceous chondrite (CI-CM) material to a dry proto-Earth, which is higher than the contribution of chondritic material advocated to account for the platinum group element budget of the mantle. Such a (relatively) high contribution of volatile-rich matter is consistent with the accretion of a few wet planetesimals during Earth accretion, as proposed by recent dynamical models. The abundance pattern of major volatile elements and of noble gases is also chondritic, with two notable exceptions. Nitrogen is depleted by one order of magnitude relative to water, carbon and most noble gases, which is consistent with either N retention in a mantle phase during magma generation, or trapping of N in the core. Xenon is also depleted by one order of magnitude, and enriched in heavy isotopes relative to chondritic or solar Xe (the so-called "xenon paradox"). This depletion and isotope fractionation might have taken place due to preferential ionization of xenon by UV light from the early Sun, either before Earth's formation on parent material, or during irradiation of the ancient atmosphere. The second possibility is consistent with a recent report of chondritic-like Xe in Archean sedimentary rocks that suggests that this process was still ongoing during the Archean eon (Pujol et al., 2011). If the depletion of Xe in the atmosphere was a long-term process that took place after the Earth-building events, then the amounts of atmospheric 129Xe and 131-136Xe, produced by the short-lived radioactivities of 129I (T 1/2 = 16 Ma) and 244Pu (T 1/2 = 82 Ma), respectively, need to be corrected for subsequent loss. Doing so, the I-Pu-Xe age of the Earth becomes ? 50 Ma after start of solar system formation, instead of ~ 120 Ma as computed with the present-day atmospheric Xe inventory.

Marty, Bernard

2012-01-01

140

Microbial degradation of. beta. -chlorinated four-carbon aliphatic acids  

SciTech Connect

Alcaligenes sp. strain CC1 is able to grow on several {alpha}-chlorinated aliphatic acids (2-chlorobutyrate, 2-chloropropionate, and chloroacetate), as well as on the {beta}-chlorinate four-carbon aliphatic acids trans-3-chlorocrotonate, cis-3-chlorocrotonate, and 3-chlorobutyrate as sole carbon and energy sources. Dehalogenation of {alpha}-chlorinated acids could be measured by using resting cells grown on all the different carbon sources, whereas dehalogenation of {beta}-chlorinated four-carbon acids could be detected only by using resting cells grown on four-carbon compounds. A constitutive 2-haloacid dehalogenase, which did not show any activity with {beta}-chlorinate four-carbon acids, was detected in cell extracts. Cell extracts of crotonate-grown cells additionally contained a {beta}-haloacid dechlorination activity, which acted on trans-3-chlorocrotante, cis-3-chlorocrotonate, and 3-chlorobutyrate and was strictly on coenzyme A, ATP, and Mg{sup 2+}. Dechlorination of {beta}-chlorinate four-carbon acids takes places after activation of the acids to their coenzyme A derivatives and seems to be independent of the constitutive 2-haloacid dehalogenase.

Kohler-Staub, D.; Kohler, H.P.E. (Univ of California, Riverside (USA))

1989-03-01

141

Biological production of ethanol from waste gases with Clostridium ljungdahlii  

DOEpatents

A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products is disclosed. The method includes introducing the waste gases into a bioreactor where they are fermented to various product, such as organic acids, alcohols H.sub.2, SCP, and salts of organic acids by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified.

Gaddy, James L. (Fayetteville, AR)

2000-01-01

142

Operational characteristics of effective removal of H2S and NH3 waste gases by activated carbon biofilter.  

PubMed

Simultaneous removal of hydrogen sulfide (H2S) and ammonia (NH3) gases from gaseous streams was studied in a biofilter packed with granule activated carbon. Extensive studies, including the effects of carbon (C) source on the growth of inoculated microorganisms and gas removal efficiency, product analysis, bioaerosol emission, pressure drop, and cost evaluation, were conducted. The results indicated that molasses was a potential C source for inoculated cell growth that resulted in removal efficiencies of 99.5% for H2S and 99.2% for NH3. Microbial community observation by scanning electron microscopy indicated that granule activated carbon was an excellent support for microorganism attachment for long-term waste gas treatment. No disintegration or breakdown of biofilm was found when the system was operated for 140 days. The low bioaerosol concentration emitted from the biofilter showed that the system effectively avoided the environmental risk of bioaerosol emission. Also, the system is suitable to apply in the field because of its low pressure drop and treatment cost. Because NH3 gas was mainly converted to organic nitrogen, and H2S gas was converted to elemental sulfur, no acidification or alkalinity phenomena were found because of the metabolite products. Thus, the results of this study demonstrate that the biofilter is a feasible bioreactor in the removal of waste gases. PMID:15115374

Chung, Ying-Chien; Lin, Yu-Yen; Tseng, Ching-Ping

2004-04-01

143

Removal potential of toxic 2378-substituted PCDD/F from incinerator flue gases by waste-derived activated carbons  

SciTech Connect

The application of activated carbons has become a commonly used emission control protocol for the removal or adsorption of persistent organic pollutants from the flue gas streams of waste incinerators. In this study, the 2378-substituted PCDD/F removal efficiency of three types of activated carbons derived from the pyrolysis of refuse derived fuel, textile waste and scrap tyre was investigated and compared with that of a commercial carbon. Experiments were carried out in a laboratory scale fixed-bed reactor under a simulated flue gas at 275 deg. C with a reaction period of four days. The PCDD/F in the solid matrices and exhaust gas, were analyzed using gas chromatography coupled with a triple quadrupole mass spectrometer. In the absence of activated carbon adsorbent, there was a significant increase in the concentration of toxic PCDD/F produced in the reacted flyash, reaching up to 6.6 times higher than in the raw flyash. In addition, there was a substantial release of PCDD/F into the gas phase, which was found in the flue gas trapping system. By application of the different commercial, refuse derived fuel, textile and tyre activated carbons the total PCDD/F toxic equivalent removal efficiencies in the exhaust gas stream were 58%, 57%, 64% and 52%, respectively. In general, the removal of the PCDDs was much higher with an average of 85% compared to PCDFs at 41%. Analysis of the reacted activated carbons showed that there was some formation of PCDD/F, for instance, a total of 60.6 {mu}g I-TEQ kg{sup -1} toxic PCDD/F was formed in the refuse derived fuel activated carbon compared to 34 {mu}g I-TEQ kg{sup -1} in the commercial activated carbon. The activated carbons derived from the pyrolysis of waste, therefore, showed good potential as a control material for PCDD/F emissions in waste incinerator flue gases.

Hajizadeh, Yaghoub; Onwudili, Jude A. [Energy and Resources Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk [Energy and Resources Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom)

2011-06-15

144

75 FR 75059 - Mandatory Reporting of Greenhouse Gases: Injection and Geologic Sequestration of Carbon Dioxide  

Federal Register 2010, 2011, 2012, 2013, 2014

...which is located in part 72 of the Acid Rain Program regulations, is expanded...replacing specific references to the Acid Rain Program and draft permits with...quarterly under 40 CFR part 75 (acid rain program); and the...

2010-12-01

145

The hyporheic zone as a source of dissolved organic carbon and carbon gases to a temperate forested stream  

USGS Publications Warehouse

The objective of this study was to examine chemical changes in porewaters that occur over small scales (cm) as groundwater flows through the hyporheic zone and discharges to a stream in a temperate forest of northern Wisconsin. Hyporheic-zone porewaters were sampled at discrete depths of 2, 10, 15, 61, and 183 cm at three study sites in the study basin. Chemical profiles of dissolved organic carbon (DOC), CO2, CH4, and pH show dramatic changes between 61 cm sediment depth and the water-sediment interface. Unless discrete samples at small depth intervals are taken, these chemical profiles are not accounted for. Similar trends were observed at the three study locations, despite each site having very different hydraulic-flow regimes. Increases in DOC concentration by an order of magnitude from 61 to 15 cm depth with a corresponding decrease in pH and rapid decreases in the molecular weight of the DOC suggest that aliphatic compounds (likely organic acids) are being generated in the hyporheic zone. Estimated efflux rates of DOC, CO2, and CH4 to the stream are 6.2, 0.79, 0.13 moles m2 d-1, respectively, with the vast majority of these materials produced in the hyporheic zone. Very little of these materials are accounted for by sampling stream water, suggesting rapid uptake and/or volatilization.

Schindler, J.E.; Krabbenhoft, D.P.

1998-01-01

146

Helium and carbon isotopic compositions of hot spring gases in the Tibetan Plateau  

Microsoft Academic Search

The Tibetan Plateau is one of the most active geothermal areas in the Himalayan Geothermal Belt. However, the heat source of the geothermal manifestation is unknown because of a lack of Quaternary volcanoes in this area, except in western Yunnan and northern Tibet. In order to unravel the heat source and the origin of volatile components in hot spring gases

Tetsuya Yokoyama; Shun'ichi Nakai; Hiroshi Wakita

1999-01-01

147

Characterization of soil organic carbon pools by acid hydrolysis  

Microsoft Academic Search

Chemically stable fractions of the soil organic carbon (SOC) contribute to the soil C sequestration and may have an important role for the global C budget. Soil organic carbon characterization was studied using acid hydrolysis methods with 1 M and 6 M HCl and hot-water extraction in two coastal plain soils collected from different landscape positions. The residues after the chemical treatments

M. L. Silveira; N. B. Comerford; K. R. Reddy; H. El-Rifai

2008-01-01

148

Apparatus for purifying arsine, phosphine, ammonia, and inert gases to remove Lewis acid and oxidant impurities therefrom  

DOEpatents

An apparatus for purifying a gaseous mixture comprising arsine, phosphine, ammonia, and/or inert gases, to remove Lewis acid and/or oxidant impurities therefrom, comprising a vessel containing a bed of a scavenger, the scavenger including a support having associated therewith an anion which is effective to remove such impurities, such anion being selected from one or more members of the group consisting of: (i) carbanions whose corresponding protonated compounds have a pK.sub.a value of from about 22 to about 36; and (ii) anions formed by reaction of such carbanions with the primary component of the mixture.

Tom, Glenn M. (New Milford, CT); Brown, Duncan W. (Wilton, CT)

1991-01-08

149

Measurement and Analysis of the Relationship between Ammonia, Acid Gases, and Fine Particles in Eastern North  

E-print Network

, which consisted of a cyclone separator; two diffusion denuders coated with sodium carbonate and citric in eastern North Carolina (i.e., an NH3-rich environment). The so- dium carbonate denuders yielded average

Aneja, Viney P.

150

The Effect of Acid Additives on Carbonate Rock Wettability and Spent Acid Recovery in Low Permeability Gas Carbonates  

E-print Network

Spent acid retention in the near-wellbore region causes reduction of relative permeability to gas and eventually curtailed gas production. In low-permeability gas carbonate reservoirs, capillary forces are the key parameters that affect the trapping...

Saneifar, Mehrnoosh

2012-10-19

151

Carbon Dioxide Information Analysis Center and World Data Center-A for atmospheric trace gases: FY 1993 activities  

SciTech Connect

During the course of a fiscal year, Oak Ridge National Laboratory`s Carbon Dioxide Information Analysis Center (CDIAC) distributes thousands of specialty publications-numeric data packages (NDPs), computer model packages (CMPs), technical reports, public communication publications, newsletters, article reprints, and reference books-in response to requests for information related to global environmental issues, primarily those pertaining to climate change. CDIAC`s staff also provide technical responses to specific inquiries related to carbon dioxide (CO{sub 2}), other trace gases, and climate. Hundreds of referrals to other researchers, policy analysts, information specialists, or organizations are also facilitated by CDIAC`s staff. This report provides an account of the activities accomplished by CDIAC (including World Data Center-A for Atmospheric Trace Gases) during the period October 1, 1992, to September 30, 1993. An organizational overview of CDIAC and its staff is supplemented by a detailed description of inquiries received and CDIAC`s response to those inquiries. An analysis and description of the preparation and distribution of NDPS, CMPS, technical reports, newsletters, fact sheets, specialty publications, and reprints are provided. Comments and descriptions of CDIAC`s information management systems, professional networking, and special bilateral agreements are also presented.

Cushman, R.M. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center; Stoss, F.W. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center]|[Univ. of Tennessee, Knoxville, TN (United States). Energy, Environment, and Resources Center

1994-01-01

152

EasyDelta: A spreadsheet for kinetic modeling of the stable carbon isotope composition of natural gases  

NASA Astrophysics Data System (ADS)

A new kinetic model and an Excel © spreadsheet program for modeling the stable carbon isotope composition of natural gases is provided in this paper. The model and spreadsheet could be used to describe and predict the variances in stable carbon isotope of natural gases under both experimental and geological conditions with heating temperature or geological time. It is a user-friendly convenient tool for the modeling of isotope variation with time under experimental and geological conditions. The spreadsheet, based on experimental data, requires the input of the kinetic parameters of gaseous hydrocarbons generation. Some assumptions are made in this model: the conventional (non-isotope species) kinetic parameters represent the light isotope species; the initial isotopic value is the same for all parallel chemical reaction of gaseous hydrocarbons generation for simplicity, the re-exponential factor ratio, 13A/ 12A, is a constant, and both heavy and light isotope species have similar activation energy distribution. These assumptions are common in modeling of isotope ratios. The spreadsheet is used for searching the best kinetic parameters of the heavy isotope species to reach the minimum errors compared with experimental data, and then extrapolating isotopic changes to the thermal history of sedimentary basins. A short calculation example on the variation in ?13C values of methane is provided in this paper to show application to geological conditions.

Zou, Yan-Rong; Wang, Lianyuan; Shuai, Yanhua; Peng, Ping'an

2005-08-01

153

Potential effects of clean coal technologies on acid precipitation, greenhouse gases, and solid waste disposal  

SciTech Connect

The US Department of Energy`s (DOE`s) Clean Coal Technology Demonstration Program (CCTDP) was initially funded by Congress to demonstrate more efficient, economically feasible, and environmentally acceptable coal technologies. Although the environmental focus at first was on sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) because their relationship to acid precipitation, the CCTDP may also lead to reductions in carbon dioxide (CO{sub 2}) emissions and in the volume of solid waste produced, compared with conventional technologies. The environmental effects of clean coal technologies (CCTs) depend upon which (if any) specific technologies eventually achieve high acceptance in the marketplace. In general, the repowering technologies and a small group of retrofit technologies show the most promise for reducing C0{sub 2} emissions and solid waste. These technologies also compare favorably with other CCTs in terms of SO{sub 2} and NO{sub x} reductions. The upper bound for CO{sup 2} reductions in the year 2010 is only enough to reduce global ``greenhouse`` warming potential by about 1%. However, CO{sub 2} emissions come from such variety of sources around the globe that no single technological innovation or national policy change could realistically be expected to reduce these emissions by more than a few percent. Particular CCTs can lead to either increases or decreases in the amount of solid waste produced. However, even if decreases are not achieved, much of the solid waste from clean coal technologies would be dry and therefore easier to dispose of than scrubber sludge.

Blasing, T.J.; Miller, R.L.; McCold, L.N.

1993-11-01

154

Anaerobic Carbon Metabolism by the Tricarboxylic Acid Cycle 1  

PubMed Central

Nitrogen-limited cells of Selenastrum minutum (Naeg.) Collins are able to assimilate NH4+ in the dark under anaerobic conditions. Addition of NH4+ to anaerobic cells results in a threefold increase in tricarboxylic acid cycle (TCAC) CO2 efflux and an eightfold increase in the rate of anaplerotic carbon fixation via phosphoenolpyruvate carboxylase. Both of these observations are consistent with increased TCAC carbon flow to supply intermediates for amino acid biosynthesis. Addition of H14CO3? to anaerobic cells assimilating NH4+ results in the incorporation of radiolabel into the ?-carboxyl carbon of glutamic acid. Incorporation of radiolabel into glutamic acid is not simply a short-term phenomenon following NH4+ addition as the specific activity of glutamic acid increases over time. This indicates that this alga is able to maintain partial oxidative TCAC carbon flow while under anoxia to supply ?-ketoglutarate for glutamate production. During dark aerobic NH4+ assimilation, no radiolabel appears in fumarate or succinate and only a small amount occurs in malate. During anaerobic NH4+ assimilation, these metabolites contain a large proportion of the total radiolabel and radiolabel accumulates in succinate over time. Also, the ratio of dark carbon fixation to NH4+ assimilation is much higher under anaerobic than aerobic conditions. These observations suggest the operation of a partial reductive TCAC from oxaloacetic acid to malate, fumarate, and succinate. Such a pathway might contribute to redox balance in an anaerobic cell maintaining partial oxidative TCAC activity. PMID:16667215

Vanlerberghe, Greg C.; Horsey, Anne K.; Weger, Harold G.; Turpin, David H.

1989-01-01

155

A sampling method based on activated carbon for gaseous mercury in ambient air and flue gases  

Microsoft Academic Search

Activated C is a useful medium for simultaneous sampling of trace gases. However, preferential canals in the C cartridge and\\u000a water vapor condensation should be avoided. The most critical component is metallic Hg. Based on the principle of permeation,\\u000a a Hg calibration gas was prepaired with a concentration range between 4 and 300 ?g·m?3. The collection efficiency of Hgo on

R. Meu

1991-01-01

156

The Effect Of Viscoelastic Surfactants Used In Carbonate Matrix Acidizing On Wettability  

E-print Network

Carbonate reservoirs are heterogeneous; therefore, proper acid placement/diversion is required to make matrix acid treatments effective. Viscoelastic surfactants (VES) are used as diverting agents in carbonate matrix acidizing. However...

Adejare, Oladapo

2012-07-16

157

Procedures for safe handling of off-gases from electric vehicle lead-acid batteries during overcharge  

SciTech Connect

The potential for generation of toxic gases from lead-acid batteries has long been recognized. Prior to the current interest in electric vehicles, there were no studies specificaly oriented to toxic gas release from traction batteries, however. As the Department of Energy Demonstration Project (in the Electric and Hybrid Vehicle Program) progresses, available data from past studies and parallel health effects programs must be digested into guidance to the drivers and maintenance personnel, tailored to their contact with electric vehicles. The basic aspects of lead-acid battery operation, vehicle use, and health effects of stibine and arsine to provide electric vehicle users with the information behind the judgment that vehicle operation and testing may proceed are presented. Specifically, it is concluded that stibine generation or arsine generation at rapid enough rates to induce acute toxic response is not at all likely. Procedures to guard against low-level exposure until more definitive data on ambient concentrations of the gases are collected are presented for both charging the batteries and driving the vehicles. A research plan to collect additional quantitative data from electric traction batteries is presented.

LaBelle, S.J.; Bhattacharyya, M.H.; Loutfy, R.O.; Varma, R.

1980-01-25

158

Simultaneous control of acid gases and PAHs using a spray dryer combined with a fabric filter using different additives.  

PubMed

The purpose of this research was to simultaneously evaluate the removal efficiency of acid gases and PAHs from the flue gas emitted by a laboratory incinerator. This flue gas contained dust, acid gases, organics and heavy metals. A spray dryer combined with a fabric filter was used as the air pollution control device (APCD) in this study. The operating conditions investigated included different feedstock additives (polyvinyl chloride (PVC) and NaCl) and spray dryer additives (SiO2, CaCl2 and NaHCO3). The removal efficiency for SO2 could be enhanced by adding inorganic additives, such as SiO2, CaCl2 and NaHCO3. The presence of PVC in the incinerator feedstock also increased the removal efficiency of SO2in the spray dryer. The improved removal of PAHs could be attributed to the addition of feedstock additives (PVC and NaCl) and spray dryer additives (SiO2, CaCl2 and NaHCO3). PMID:11900910

Liu, Zhen Shu; Wey, Ming Yen; Lin, Chiou Liang

2002-04-26

159

Fluorecently labeled bionanotransporters of nucleic acid based on carbon nanotubes  

E-print Network

Here we propose the approach to design of the new type of hybrids of oligonucleotides with fluorescein-functionalized single-walled carbon nanotubes. The approach is based on stacking interactions of functionalized nanotubes with pyrene residues in conjugates of oligonucleotides. The amino- and fluorescein-modified single-walled carbon nanotubes were obtained, and their physico-chemical properties were investigated. The effect of carbon nanotubes functionalization type on the efficacy of sorption of pyrene conjugates of oligonucleotides was examined. Proposed non-covalent hybrids of fluorescein-labeled carbon nanotubes with oligonucleotides may be used for intracellular transport of functional nucleic acids.

Novopashina, D S; Venyaminova, A G

2012-01-01

160

Carbon formation on metal carbides in chlorine-containing gases at high temperature  

NASA Astrophysics Data System (ADS)

The formation of a carbon film on exposed surfaces has been observed after corrosion of silicon carbide, TiC, and TaC materials in chlorine containing environments. The formation of carbon film during chlorination of silicon carbide and some metal carbides are expected thermodynamically because of the relative stability of silicon or metal halides in comparison to carbon halogen compounds. Carbon or carbide coatings are widely used to improve the properties of engineering materials. Carbon coating with varying structure and composition are applied in fields from tribology to catalysis. There is not yet sufficient published information about the structure and properties of carbon films produced by etching in halogen containing media to determine whether these coatings have useful properties. This paper reports the results of investigations on the carbon films formed on beta-SiC, TiC, and TaC, after exposure to atmospheres containing chlorine and its compounds. Raman spectroscopy, XRD, and SEM have been applied to characterize the effects of the environment and substrate on the structure and properties of carbon film. In addition, spsp3-C rich carbon (or DLC, diamond) was formed on the surface of beta-SiC powder by the reaction in a chlorine-hydrogen gas mixture at atmospheric pressure and temperature 800-900 C.

Jeon, In-Deok

161

High rate chemical vapor deposition of carbon films using fluorinated gases  

DOEpatents

A high rate, low-temperature deposition of amorphous carbon films is produced by PE-CVD in the presence of a fluorinated or other halide gas. The deposition can be performed at less than 100.degree. C., including ambient room temperature, with a radio frequency plasma assisted chemical vapor deposition process. With less than 6.5 atomic percent fluorine incorporated into the amorphous carbon film, the characteristics of the carbon film, including index of refraction, mass density, optical clarity, and chemical resistance are within fifteen percent (15%) of those characteristics for pure amorphous carbon films, but the deposition rates are high.

Stafford, Byron L. (Arvada, CO); Tracy, C. Edwin (Golden, CO); Benson, David K. (Golden, CO); Nelson, Arthur J. (Longmont, CO)

1993-01-01

162

Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films  

SciTech Connect

The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CN{sub x}) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inert gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N{sub 2} was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CN{sub x} thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CN{sub x} films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CN{sub x} thin films.

Schmidt, Susann; Czigany, Zsolt; Greczynski, Grzegorz; Jensen, Jens; Hultman, Lars [Thin Film Physics Div., Department of Physics (IFM), Linkoeping University, SE-581 83 (Sweden); Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklos ut 29-33. H-1121 Budapest (Hungary); Thin Film Physics Div., Department of Physics (IFM), Linkoeping University, SE-581 83 (Sweden)

2013-01-15

163

Trends in source gases  

NASA Technical Reports Server (NTRS)

Source gases are defined as those gases that, by their breakdown, introduce into the stratosphere halogen, hydrogen, and nitrogen compounds that are important in stratospheric ozone destruction. Given here is an update of the existing concentration time series for chlorocarbons, nitrous oxide, and methane. Also reviewed is information on halogen containing species and the use of these data for establishing trends. Also reviewed is evidence on trends in trace gases that influence tropospheric chemistry and thus the tropospheric lifetimes of source gases, such as carbon dioxide, carbon monoxide, or nitrogen oxides. Much of the information is given in tabular form.

Ehhalt, D. H.; Fraser, P. J.; Albritton, D.; Cicerone, R. J.; Khalil, M. A. K.; Legrand, M.; Makide, Y.; Rowland, F. S.; Steele, L. P.; Zander, R.

1989-01-01

164

Nature of the carbon and sulfur phases and inorganic gases in the Kenna ureilite  

NASA Technical Reports Server (NTRS)

Abundances of carbon and sulfur in the Kenna ureilite are 2.219 plus or minus 0.060 wt. % C and 0.179 plus or minus 0.008 wt. % S. Secondary carbonates resulting from terrestrial weathering account for 0.25 plus or minus 0.02 wt. % C. No hydrocarbons were detected during gas release measurements. Most of the carbon is in graphite, diamond, or lonsdaleite. The sample of Kenna contained 0.95 plus or minus 0.05 wt.% H2O. Total carbon and sulfur measurements were made on three additional ureilites: Havero, Dingo Pup Donga, and North Haig. Ureilite carbon abundances are similar to those of C-2 chondrites, whereas sulfur abundances are a factor of 10 less than C-2 chondrites and ordinary chondrites. The elemental abundances, ratios, and phases present in the ureilites rule out a direct genetic relationship between the ureilites and the carbonaceous chondrites.

Gibson, E. K., Jr.

1976-01-01

165

PREDICTING TEMPERATURE BEHAVIOR IN CARBONATE ACIDIZING TREATMENTS  

E-print Network

is the heat generated by reaction, affecting the temperature behavior significantly. The result of the thermal model showed significant temperature effects caused by reaction, providing a mechanism to quantitatively determine the acid flow profile. Based... penetration and include the reaction between acid and rock. 5 ? Integrate the flow-back part into the program to achieve the temperature behavior in the wellbore. ? Study the sensitivity of flow-back temperature in the wellbore to the injection rate...

Tan, Xuehao

2010-01-16

166

Sorption of noble gases by solids, with reference to meteorites. I - Magnetite and carbon  

NASA Technical Reports Server (NTRS)

The trapping of meteoritic noble gases by solids is simulated through the synthesis of 18 Fe3O4 samples at 350-720 K in a noble gas atmosphere, by means of the reactions: (1) 3Fe + 4H2O yields Fe3O4 + 4H2, using Ne, Ar, Kr and Xe; and (2) 3Fe + 4CO yields Fe3O4 + 4C + carbides, using Xe. Etching experiments suggest an analogy with 'Phase Q' in meteorites. Adsorbed atmospheric gases are present in all samples, and dominate whenever the noble gas partial pressure in the atmosphere is greater than that in the synthesis. While many of the results of Lancet and Anders (1973) appear to have been dominated by such an atmospheric component, others are suspect. When the doubtful samples of Lancet and Anders are corrected or eliminated, the fractionation pattern no longer peaks at Ar, but rather, as in the present sample, rises monotonically from Ne to Xe. No evidence is found for the earlier study's claim of a strong temperature dependence.

Yang, J.; Lewis, R. S.; Anders, E.

1982-01-01

167

FIELD METHOD COMPARISON FOR THE CHARACTERIZATION OF ACID AEROSOLS AND GASES  

EPA Science Inventory

This paper presents findings from two intercomparison studies of acid aerosol measurement systems, which were conducted in Uniontown and State College, PA, during the summers of 1990 and 1991, respectively. s part of these studies, acid aerosol and gas concentrations (NH3, HNO3, ...

168

The HIPPO (HIAPER Pole-to-Pole Observations) study of the carbon cycle and greenhouse gases measured meteorology, atmospheric chemistry, and aerosol constituents along transects from approximately pole-to-pole  

E-print Network

The HIPPO (HIAPER Pole-to-Pole Observations) study of the carbon cycle and greenhouse gases measured meteorology, atmospheric chemistry, and aerosol constituents along transects from approximately of a comprehensive suite of atmospheric trace gases and aerosols pertinent to understanding the carbon cycle

169

Do Agricultural Soils of California have the Potential to Sequester Carbon and Mitigate Greenhouse Gases?  

NASA Astrophysics Data System (ADS)

Agricultural ecosystems play a major role in the global carbon cycle and can be both sources of carbon emissions to the atmosphere and also carbon sinks which may be used to offset any future greenhouse gas (GHG) emissions. In California, climate change predictions indicate major impacts and substantial alterations of agricultural systems over the next decades. In 2006, California passed the California Global Warming Solutions Act of 2006 (AB 32) that requires reduction of the three major GHG's (CO2, N2O and CH4) to 1990 levels by 2020. We surveyed and synthesized available data from recent studies describing the potential to sequester carbon and reduce other GHG emissions in California agricultural soils. The studies evaluated various management practices in both annual row and perennial cropping systems, with other studies focusing upon biogeochemical model predictions for carbon sequestration and GHG mitigation calibrated towards California agriculture. Management practices considered included minimum or no tillage, cover cropping, organic residue (low and high inputs) and nitrogen fertilizer management. Though practices involving inputs of carbon, such as cover cropping and organic amendments, were often associated with increases in soil organic carbon (SOC) in the top soil layer (0-20 cm), results were not consistent across farming systems. Several studies indicated that conservation tillage, alone, increased above-ground biomass, especially when used with a cover crop. However, the reduced soil disturbance from conservation tillage merely resulted in a redistribution of the soil carbon rather than an overall accumulation, when compared with standard tillage and cover cropping practices together. Predictions from biogeochemical models indicated that increased inputs of manure and increased organic residues led to substantial carbon sequestration but did not consistently reduce non-CO2 related GHG emissions. The most effective way to reduce non-CO2 GHG emissions, and simultaneously add organic matter to soil, was to employ reduced tillage techniques and low input farming which is based upon the reduction of chemical fertilizers, pesticides and herbicides without their complete elimination and to also add carbon to the soils through the addition and incorporation of organic amendments and cover crops.

Suddick, E. C.; Scow, K. M.; Six, J. W.

2008-12-01

170

Photosynthesis In Elodea canadensis Michx: Four-Carbon Acid Synthesis.  

PubMed

Experiments to determine the early labeled photosynthetic products in Elodea canadensis show that after 2 seconds of exposure to NaH(14)CO(3), 45% of the (14)C incorporated is located in malate and aspartate. Phosphoglyceric acid and sugars account for 27% of the label during similar exposures. Equivalent amounts of organic acids and C(3) cycle products are present after 8 seconds. Four-carbon acids remain relatively unchanged throughout the first 45 seconds of exposure, while sugars increase in a linear fashion. Enzyme assays indicate that ribulose diphosphate and phosphoenolpyruvate carboxylase enzymes are present in a ratio of approximately 2:1. It appears that E. canadensis is able to synthesize significant amounts of four-carbon acids via beta-carboxylation and this may play a role in maintaining a pH favorable for carboxylation in aquatic plants. PMID:16660008

Degroote, D; Kennedy, R A

1977-06-01

171

Effective matrix acidizing in carbonates using microemulsions  

SciTech Connect

The process of matrix acidizing of oil reservoirs is described. It is designed to improve well productivity by increasing rock permeability in the region surrounding the wellbore. As resistance to flow is reduced, oil can move more easily to the wellbore and production increases. A reacting mixture, usually containing HCI for limestone and an HCI/HF mixture for sandstone, is pumped into the well at pressures low enough to avoid fracturing the formation rock or to open existing fractures. The goal is to achieve a somewhat uniform radial penetration of acid into the formation porespace. Partial dissolution of the matrix can then take place, and rock permeability is increased.

Hoefner, M.L.; Fogler, H.S.

1985-05-01

172

Evaluation of carbon dioxide mass transfer in raceway reactors for microalgae culture using flue gases.  

PubMed

Mass transfer of CO2 from flue gas was quantified in a 100m(2) raceway. The carbonation sump was operated with and without a baffle at different liquid/gas ratios, with the latter having the greatest influence on CO2 recovery from the flue gas. A rate of mass transfer sufficient to meet the demands of an actively growing algal culture was best achieved by maintaining pH at ?8. Full optimisation of the process required both pH control and selection of the best liquid/gas flow ratio. A carbon transfer rate of 10gCmin(-1) supporting an algal productivity of 17gm(-2)day(-1) was achieved with only 4% direct loss of CO2 in the sump. 66% of the carbon was incorporated into biomass, while 6% was lost by outgassing and the remainder as dissolved carbon in the liquid phase. Use of a sump baffle required additional power without significantly improving carbon mass transfer. PMID:24374031

de Godos, I; Mendoza, J L; Acién, F G; Molina, E; Banks, C J; Heaven, S; Rogalla, F

2014-02-01

173

Evaluation of Perforated Carbonate Cores Under Acid Stimulation  

E-print Network

to evaluate the impact of reactive charges on acid wormholing in representative carbonate cores. A set of oil-saturated Indiana limestone and cream chalk cores have been perforated under simulated downhole conditions using either a conventional or a... thankful to Mohamed Mahmoud for running the chemical analysis of the core effluent fluids and Yanbin Zhang for teaching me everything needed to perform the acidizing experiments. I am also very thankful to John Maldonado for all his time and help...

Diaz, Nerwing Jose

2011-10-21

174

Partitioning and removal of dioxin-like congeners in flue gases treated with activated carbon adsorption.  

PubMed

Activated carbon adsorption is commonly used to control dioxin-like congener (PCDD/Fs and PCBs) emissions. Partitioning of PCDD/Fs and PCBs between vapor and solid phases and their removal efficiencies achieved with existing air pollution control devices (APCDs) at a large-scale municipal waste incinerator (MWI) and an industrial waste incinerator (IWI) are evaluated via intensive stack sampling and analysis. Those two facilities investigated are equipped with activated carbon injection (ACI) with bag filter (BF) and fixed activated carbon bed (FACB) as major PCDD/F control devices, respectively. Average PCDD/F and PCB concentrations of stack gas with ACI+BF as APCDs are 0.031 and 0.006ng-TEQ/Nm(3), and that achieved with FACB are 1.74 and 0.19ng-TEQ/Nm(3) in MWI and IWI, respectively. The results show that FACB could reduce vapor-phase PCDD/Fs and PCBs concentrations in flue gas, while the ACI+BF can effectively adsorb the vapor-phase dioxin-like congener and collect the solid-phase PCDD/Fs and PCBs in the meantime. Additionally, the results of the pilot-scale adsorption system (PAS) experimentation indicate that each gram activated carbon adsorbs 105-115ng-PCDD/Fs and each surface area (m(2)) of activated carbon adsorbs 10-25ng-PCDD/Fs. Based on the results of PAS experimentation, this study confirms that the surface area of mesopore+macropore (20-200A) of the activated carbon is a critical factor affecting PCDD/F adsorption capacity. PMID:16488462

Chi, Kai Hsien; Chang, Shu Hao; Huang, Chia Hua; Huang, Hung Chi; Chang, Moo Been

2006-08-01

175

A Pilot-Scale Evaluation of a New Technology to Control NO(x) Emissions from Boilers at KSC: Hydrogen Peroxide Injection into Boiler Flue Gases Followed by Wet Scrubbing of Acid Gases  

NASA Technical Reports Server (NTRS)

Emissions of nitrogen oxides NO(x) are a significant problem in the United States. NO(x) are formed in any combustion process, therefore it is not surprising that NO(x) are emitted from the boilers at KSC. Research at UCF has shown (in the laboratory) that injecting H2O2 into hot simulated flue gases can oxidize the NO and NO2 to their acid gas forms, HNO2 and HNO3, respectively. These acid gases are much more water soluble than their counterparts, and theoretically can be removed easily by wet scrubbing. This technology was of interest to NASA, both for their boilers at KSC, and for their combustion sources elsewhere. However, it was necessary to field test the technology and to provide pilot-scale data to aid in design of full-scale facilities. Hence this project was initiated in May of 1996.

Cooper, C. David

1997-01-01

176

Theoretical estimates of equilibrium 13C-18O clumping in carbonates and organic acids  

NASA Astrophysics Data System (ADS)

The development of techniques for measuring small gas-phase molecules containing more than one rare stable isotope (e.g., 13C18O16O) at natural, ppm-level abundances1,2 has made it possible to track sources and sinks of atmospheric gases from a new perspective. Similar measurements of 13C-18O clumping in ancient samples could improve our understanding of ancient climates, if the abundances of `clumped' rare stable isotopes in materials that retain isotopic signatures over geologic time can be measured with sufficient precision. This theoretical study estimates the abundances of such 13C-18O `clumps' in carbonates and organic acids and discusses their potential applications. Accompanying abstracts by Eiler et al. and Ghosh et al. will present the analytical methods and some initial data for carbonate minerals to examine the applicability of our theoretical models. Equilibrium isotopic speciations in carbonate minerals and organic acids are calculated from the reduced partition function ratios of isotopically substituted crystals and molecules. Vibrational frequencies used as input for these calculations come from ab initio force fields, determined using density functional theory. Our calculations indicate that carbonate minerals, including calcite, dolomite, and aragonite, when equilibrated at earth-surface temperatures, will have a slight overabundance of CO32- groups containing both 13C and 18O (i.e., 13C18O16O22-) relative to what would be expected if carbon and oxygen isotopes were distributed randomly in the crystal lattice. Calcite and dolomite crystals are predicted to have 0.4‰ excesses of 13C18O16O22- at 298 K; in aragonite the excess will be about 0.05‰ larger. The excesses are smaller for crystals formed or equilibrated at higher temperatures, decreasing by 0.003\\permil/oC at room temperature and essentially disappearing at temperatures of 1000 K or higher. Similarly, there is an excess of both 13C18O16OH and 13C16O18OH groups in organic acids like formic acid (HCOOH) and pyruvic acid (CH3COCOOH) that equilibrate at low temperatures. For gas-phase carboxylic acids, 13C-18O clumping in the COOH group is strongest at the C=O double bond, with an 1.0-1.1‰ excess at room temperature. The C-O-H subgroup has an ~0.4‰ 13C-18O excess, and thus the average anomaly for the whole COOH group is 0.7-0.8\\permil. As with carbonate minerals, these excesses decrease at higher temperatures. The magnitude of 13C-18O clumping in carboxylic acid is similar to gas-phase CO2 1,2,3, while in carbonate minerals the effect is about one-half as large. The temperature sensitivity of these isotopic clumping effects suggests that measurements of abundances of 13C-18O bonds in carbonates and organic acids could be useful for paleothermometry. The clumping equilibrium is an internal property of each phase, so temperature information can be obtained even when the isotopic composition of the fluid phase from which a sample precipitated is unknown. Clumping effects may also be able to distinguish pristine, unaltered sedimentary and biogenic carbonates and organic deposits from those that have undergone post-depositional diagenesis or metamorphism, even in samples that have not suffered extensive open-system exchange. Refs: 1Eiler et al. 2004, GCA in press; 2Schauble et al. in prep.; 3Wang et al. 2004, GCA in press.

Schauble, E. A.; Eiler, J. M.

2004-12-01

177

Effects of Biochar and Basalt Additions on Carbon Sequestration and Fluxes of Greenhouse Gases in Soils  

E-print Network

and combinations within agricultural soil. Analyses included comparisons of soil pH, moisture content, total carbon naturally improving soil health. Results of this investigation show that soils treated with different levels in Soils Zachary Pinto Program in Environmental Studies Middlebury College Middlebury, VT 05753

Vallino, Joseph J.

178

Shock-tube thermochemistry tables for high-temperature gases. Volume 5: Carbon dioxide  

NASA Technical Reports Server (NTRS)

Equilibrium thermodynamic properties and species concentrations for carbon dioxide are tabulated for moving, standing, and reflected shock waves. Initial pressures range from 6.665 to 6665 N/sq m (0.05 to 50.0 torr), and temperatures from 2,000 to over 80,000K. In this study, 20 molecular and atomic species were considered.

Menard, W. A.; Horton, T. E.

1971-01-01

179

MANAGING FOR MITIGATION OF GREENHOUSE GASES AND CARBON SEQUESTRATION IN THE MIDWEST  

Technology Transfer Automated Retrieval System (TEKTRAN)

The central USA contains some of the most productive agricultural land in the world. Due to the high proportion of land area committed to crops and pasture in this region, the carbon (C) stored and greenhouse gas (GHG) emissions represent a large percentage of the total for US agriculture. Our objec...

180

ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID  

EPA Science Inventory

The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot m...

181

Sulfuric acid vapor and other cloud-related gases in the Venus atmosphere - Abundances inferred from observed radio opacity  

NASA Technical Reports Server (NTRS)

It is suggested that the absorbing characteristics of sulfuric acid vapor appear to reconcile what had been thought to be an inconsistency among measurements and deductions regarding the constituents of the Venus atmosphere and radio occultation, radar reflection, and radio emission measurements of its opacity. Laboratory measurements of sulfuric acid, sulfur dioxide, water vapor, and carbon dioxide are used to model relative contributions to opacity as a function of height in a way that is consistent with observations of the constituents and absorbing properties of the atmosphere. It is concluded that sulfuric acid vapor is likely to be the principal microwave absorber in the 30-50 km altitude range of the middle atmosphere of Venus.

Steffes, P. G.; Eshleman, V. R.

1982-01-01

182

Synthesis and acid catalysis of cellulose-derived carbon-based solid acid  

NASA Astrophysics Data System (ADS)

SO 3H-bearing amorphous carbon, prepared by partial carbonization of cellulose followed by sulfonation in fuming H 2SO 4, was applied as a solid catalyst for the acid-catalyzed hydrolysis of ?-1,4 glucan, including cellobiose and crystalline cellulose. Structural analyses revealed that the resulting carbon material consists of graphene sheets with 1.5 mmol g -1 of SO 3H groups, 0.4 mmol g -1 of COOH, and 5.6 mmol g -1 of phenolic OH groups. The carbon catalyst showed high catalytic activity for the hydrolysis of ?-1,4 glycosidic bonds in both cellobiose and crystalline cellulose. Pure crystalline cellulose was not hydrolyzed by conventional strong solid Brønsted acid catalysts such as niobic acid, Nafion ® NR-50, and Amberlyst-15, whereas the carbon catalyst efficiently hydrolyzes cellulose into water-soluble saccharides. The catalytic performance of the carbon catalyst is due to the large adsorption capacity for hydrophilic reactants and the adsorption ability of ?-1,4 glucan, which is not adsorbed to other solid acids.

Suganuma, Satoshi; Nakajima, Kiyotaka; Kitano, Masaaki; Yamaguchi, Daizo; Kato, Hideki; Hayashi, Shigenobu; Hara, Michikazu

2010-06-01

183

Partitioning and removal of dioxin-like congeners in flue gases treated with activated carbon adsorption  

Microsoft Academic Search

Activated carbon adsorption is commonly used to control dioxin-like congener (PCDD\\/Fs and PCBs) emissions. Partitioning of PCDD\\/Fs and PCBs between vapor and solid phases and their removal efficiencies achieved with existing air pollution control devices (APCDs) at a large-scale municipal waste incinerator (MWI) and an industrial waste incinerator (IWI) are evaluated via intensive stack sampling and analysis. Those two facilities

Kai Hsien Chi; Shu Hao Chang; Chia Hua Huang; Hung Chi Huang; Moo Been Chang

2006-01-01

184

Palm oil and the emission of carbon-based greenhouse gases  

Microsoft Academic Search

The current use of South Asian palm oil as biofuel is far from climate neutral. Dependent on assumptions, losses of biogenic carbon associated with ecosystems, emission of CO2 due to the use of fossil fuels and the anaerobic conversion of palm oil mill effluent currently correspond in South Asia with an emission of about 2.8–19.7kg CO2 equivalent per kg of

L. Reijnders; M. A. J. Huijbregts

2008-01-01

185

Carbon dioxide analysers: accuracy, alarm limits and effects of interfering gases  

Microsoft Academic Search

Six mainstream and twelve sidestream infrared carbon dioxide (CO2) analysers were tested for accuracy of the CO2 display value, alarm activation and the effects of nitrous oxide (N2O), oxygen (O2) and water vapour according to the ISO Draft International Standard (DIS) #9918. Mainstream analysers (M-type): Novametrix\\u000a Capnogard 1265; Hewlett Packard HP M1166A (CO2module HP M1016A); Datascope Passport; Marquette Tramscope 12;

Rolf Lauber; Bruno Seeberger; Alex Martin Zbinden

1995-01-01

186

Photochemistry of biogenic gases  

NASA Technical Reports Server (NTRS)

The relationship between the biosphere and the atmosphere is examined, emphasizing the composition and photochemistry and chemistry of the troposphere and stratosphere. The reactions of oxygen, ozone, and hydroxyl are reviewed and the fate of the biogenic gases ammonia, methane, reduced sulfur species, reduced halogen species, carbon monoxide, nitric oxide, nitrous oxide, nitrogen, and carbon dioxide are described. A list is given of the concentration and sources of the various gases.

Levine, Joel S.

1989-01-01

187

Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.  

PubMed

Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 ?g m(-3)) was 2.7 times higher than nitrous acid (1.0 ?g m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 ?g m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area. PMID:22358115

Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

2012-05-01

188

ACIDIC GASES AND AEROSOLS IN THE EASTERN AND WESTERN UNITED STATES  

EPA Science Inventory

The USEPA National Dry Deposition Network (NDDN) is designed to provide long-term estimates of acidic gas and aerosol concentrations, and associated fluxes, across the continental United States. nspection of data collected since 1988 shows species-dependent variability in atmosph...

189

Differences in response between 18 carbon fatty acids and 12 14 carbon saturated fatty acids on plasma cholesterol in Guinea pigs  

Microsoft Academic Search

Male guinea pigs were fed four different diets rich in lauric plus myristic (LM), stearic (ST), oleic (OL) or linoleic (LN) fatty acids to compare the effects of 18 carbon fatty acids with different degrees of saturation with 1214 carbon saturated fatty acids on hepatic cholesterol metabolism. Animals fed the LM diet had 76–100% higher plasma total cholesterol and apo

Maria Luz Fernandez; Cristina Avalos; Marcela Vergara-Jimenez

1998-01-01

190

Separation and identification of carboxylic acids in MALT samples from the headspace gases in Hanford tank 103C  

SciTech Connect

Samples of headspace gases from Westinghouse Hanford Company (WHC) waste storage tank 103C were analyzed by gas chromatography/mass spectrometry by Pacific Northwest Laboratory staff. The samples were obtained using a cryo-trap sampler designed by WHC and known as the Mobile Analytical Laboratory Trap (MALT). The samples, which were obtained in September 1989, were available in large amounts (200 mi). The specific targets for this analysis were n-butyric, i-butyric, n-valeric, and i-valeric organic acids. Of the acids targeted, only n-butyric was found, and only trace amounts of it were detected with a detection limit below 1 ppM in the extract. The levels found were so low as to cause difficulty in quantitation. All concentrations reported here are for the methanol extract solutions and not the concentrations in the headspace of tank 103C. To calculate concentrations in the headspace, the MALT sampling volume and the methanol rinse volume must be obtained from the MALT personnel at WHC.

Clauss, S.A.; Lucke, R.B.

1993-08-01

191

Total organic carbon concentrations in acidic lakes in southern Norway  

SciTech Connect

Regional surveys in Norway demonstrate that most of the lakes have low concentrations of total organic carbon (TOC); 60% of the lakes had TOC < 2 mg/L and 90% had TOC < 6 mg/L. There was no apparent relationship between lake water pH and TOC. For the 1005 lakes sampled throughout Norway in 1986, organic anions represent <10% of the anions in all ranges of lake water pH. In the acidic lakes in southern Norway, TOC concentrations and the contributions of organic acids to acidity were very low. Lake water TOC decreased markedly with elevation and all lakes above 900 m had TOC < 2 mg/L. Strong acid concentrations were a function of base cation, excess sulfate, TOC, and NO/sub 3/ concentrations, but only 1.6% of the variation in strong acids in southernmost Norway was explained by TOC. The acidic lakes in southern Norway was explained by TOC. The acidic lakes in southern Norway sampled by regional surveys are mainly inorganic solutions with concentrations of excess sulfate that are high relative to base cations and with little contribution of organic anions to acidity.

Henriksen, A.; Brakke, D.F.; Norton, S.A.

1988-09-01

192

Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media  

PubMed Central

The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40?°C, 0.2?M formic acid can be obtained under 200?bar, however, in DMSO the same catalyst affords 1.9?M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes. PMID:24886955

Moret, Séverine; Dyson, Paul J.; Laurenczy, Gábor

2014-01-01

193

Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media.  

PubMed

The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40?°C, 0.2?M formic acid can be obtained under 200?bar, however, in DMSO the same catalyst affords 1.9?M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes. PMID:24886955

Moret, Séverine; Dyson, Paul J; Laurenczy, Gábor

2014-01-01

194

Adsorption of noble gases on individual suspended single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Suspended single-walled carbon nanotubes can act as nanomechanical resonators, offering the ability to detect an adsorbed substance with very high sensitivity via the frequency shift due to the adsorbed mass. By measuring the resonance frequency electrically in the presence of vapors at controlled temperature and pressure we have obtained isotherms for 4He, Ar, Kr and Xe, on multiple nanotubes. The behavior resembles that on graphite but with notable differences, including weaker binding energies. The lower binding allows access to behavior at lower 2D chemical potential than on conventional substrates. For 4He the binding energy is reduced by as much as a factor of two. For Ar the derived two-dimensional phase diagram is similar to that on conventional substrates. For Kr there is variation between nanotubes which may be related to commensurability and area per site on the surface of a cylinder. Work supported by NSF DMR 0907690.

Lee, Hao-Chun; Wang, Zenghui; Roy, Richard; Fredrickson, Erik; Vilches, Oscar; Cobden, David

2012-02-01

195

Laboratory simulation of meteoritic noble gases. II - Sorption of xenon on carbon: Etching and heating experiments  

NASA Technical Reports Server (NTRS)

The release of trapped Xe from amorphous-C phases of meteorites is simulated experimentally by HNO3 etching of carbon-black and pyrolyzed polyvinylidene chloride samples exposed to Xe-127 for 0.5-240 h at 100-1000 C and then degassed for 9 h or more at the same temperatures, as reported by Wacker et al. (1985). The results are presented in tables and graphs and characterized in detail. Samples exposed at 100-200 C are found to lose most of their Xe after etching to a depth of only about 20 pm, while those exposed at 800-1000 C exhibit a second more tightly bound component extending to a depth of 3 nm, indicative of diffusion of Xe during exposure and resembling planetary Xe. The higher noble-gas concentrations measured in meteorites are attributed to rate-controlled Xe uptake over a long period in the solar nebula.

Zadnik, M. G.; Wacker, J. F.; Lewis, R. S.

1985-01-01

196

Carbon and nitrogen dynamics and greenhouse gases emissions in constructed wetlands: a review  

NASA Astrophysics Data System (ADS)

The nitrogen (N) removal efficiency of constructed wetlands (CWs) is very inconsistent and does not alone explain if the removed species are reduced by physical attenuation or if they are transformed to other reactive forms (pollution swapping). There are many pathways for the removed N to remain in the system: accumulation in the sediments, leaching to groundwater (nitrate-NO3- and ammonium-NH4+), emission to atmosphere via nitrous oxide- N2O and ammonia and/or conversion to N2 gas and adsorption to sediments. The kinetics of these pathways/processes varies with CWs management and therefore needs to be studied quantitatively for the sustainable use of CWs. For example, the quality of groundwater underlying CWs with regards to the reactive N (Nr) species is largely unknown. Equally, there is a dearth of information on the extent of Nr accumulation in soils and discharge to surface waters and air. Moreover, CWs are rich in dissolved organic carbon (DOC) and produce substantial amounts of CO2 and CH4. These dissolved carbon (C) species drain out to ground and surface waters and emit to the atmosphere. The dynamics of dissolved N2O, CO2 and CH4 in CWs is a key "missing piece" in our understanding of global greenhouse gas budgets. In this review we provide an overview of the current knowledge and discussion about the dynamics of C and N in CWs and their likely impacts on aquatic and atmospheric environments. We suggest that the fate of various N species in CWs and their surface emissions and subsurface drainage fluxes need to be evaluated in a holistic way to better understand their potential for pollution swapping. Research on the process based N removal and balancing the end products into reactive and benign forms are critical to assess environmental impacts of CWs. Thus we strongly suggest that in situ N transformation and fate of the transformation products with regards to pollution swapping requires further detailed examination.

Jahangir, M. M. R.; Fenton, O.; Gill, L.; Müller, C.; Johnston, P.; Richards, K. G.

2014-07-01

197

Robust IR Remote Sensing Technique of the Total Column of Trace Gases Including Carbon Dioxide and Methane  

NASA Technical Reports Server (NTRS)

Progress on the development of a differential radiometer based upon the Fabry-Perot interferometer (FPI) for methane (CH4) and carbon dioxide (C02) detection in the atmosphere is presented. Methane measurements are becoming increasingly important as a component of NASA's programs to understand the global carbon cycle and quantifY the threat of global warming. Methane is the third most important greenhouse gas in the Earth's radiation budget (after water vapor and carbon dioxide) and the second most important anthropogenic contributor to global warming. The importance of global warming and air quality to society caused the National Research Council to recommend that NASA develop the following missions [1]: ASCENDS (Active Sensing of C02 Emissions over Nights, Days, and Seasons), GEOCAPE (Geostationary Coastal and Air Pollution Events), and GACM (Global Atmosphere Composition Mission). Though methane measurements are not specifically called out in these missions, ongoing environmental changes have raised the importance of understanding the methane budget. In the decadal survey is stated that "to close the carbon budget, we would also address methane, but the required technology is not obvious at this time. If appropriate and cost-effective methane technology becomes available, we strongly recommend adding a methane capability". In its 2007 report the International Panel on Climate Change identified methane as a key uncertainty in our understanding saying that the causes of recent changes in the growth rate of atmospheric CH4 are not well understood. What we do know is that methane arises from a number of natural sources including wet lands and the oceans plus man made sources from agriculture, as well as coal and petroleum production and distribution. It has recently been pointed out that large amount of methane are frozen in the permafrost of Canada and Siberia. There is a fear that melting of this permafrost driven by global warming may release large amounts of methane very suddenly further exacerbating climate change [2]. Last year our group began a joint effort with Johns Hopkins Applied Physics Laboratory to investigate the possibility of developing a small unmanned aerial vehicle (UAV) equipped to measure greenhouse gases-particularly methane. Although we are targeting our system for smaller UAV's the instrument will be directly applicable to missions involving larger NASA UAV's such as Global Hawk or even on missions utilizing manned aircraft. Because of its small size, inherent ruggedness and simplicity some version of our proposed instrument may find a role as a satellite instrument for NASA or NOAA.

Georgieva, E. M.; Heaps, W. S.

2011-01-01

198

Amino acids of the Murchison meteorite. III - Seven carbon acyclic primary alpha-amino alkanoic acids  

NASA Technical Reports Server (NTRS)

All of the eighteen possible seven-carbon acyclic primary alpha-amino alkanoic acids have been positively identified in a hot-water extract of the Murchison meteorite by the combined use of gas chromatography-mass spectrometry, ion exchange chromatography and reversed-phase chromatography. None of these amino acids has previously been found in meteorites or in any other natural material. They range in concentration from less than or equal to 0.5 to 5.3 nmol/g. Configuration assignments were made for 2-amino-3,4-dimethylpentanoic acid and allo-2-amino-3,4-dimethylpentanoic acid and the diasteromer ratio was determined. Fifty-five amino acids have now been positively identified in the Murchison meteorite, 36 of which are unknown in terrestrial materials. This unique suite of amino acids is characterized by the occurrence of all structural isomers within the two major classes of amino acids represented, by the predominance of branched chain isomers, and by an exponential decline in amount with increasing carbon chain length within homologous series. These characteristics of the Murchison amino acids are suggestive of synthesis before incorporation into a parent body.

Cronin, John R.; Pizzarello, Sandra

1986-01-01

199

Capture of carbon dioxide from flue gases by amine-functionalized TiO2 nanotubes  

NASA Astrophysics Data System (ADS)

The novel carbon dioxide (CO2) adsorbents with high capture efficiency were prepared through impregnating TiO2 nanotubes (TiNT) with four kinds of amines, namely monoethanolamine (MEA), ethylenediamine (EDA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), respectively. The samples were characterized by thermogravimetric analysis, low temperature N2 adsorption and transmission electron microscopy. CO2 capture was investigated in a dynamic packed column. The TEPA-loaded sample showed a better adsorption capacity due to its higher amino-groups content. In condition, TiNT-TEPA-69 shows the highest CO2 adsorption capacity among the four TEPA-loaded samples, approximately 4.37 mmol/g at 60 °C. The adsorption capacity was enhanced to 5.24 mmol/g under moisture conditions. TiNT-TEPA-69 was selected as adsorbent to study the adsorption/desorption behavior in the absence of moisture and in the presence of moisture. While the former is fairly stable after 5 adsorption/desorption cycles, the latter decreases dramatically.

Song, Fujiao; Zhao, Yunxia; Cao, Yan; Ding, Jie; Bu, Yunfei; Zhong, Qin

2013-03-01

200

The Chemistry of Biological Gases  

Microsoft Academic Search

\\u000a Today there are at least four biological gases: oxygen (O2), nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide\\u000a (H2S). Except for molecular oxygen, many of these gases were originally known for their detrimental physiological effects.\\u000a However, the current consensus suggests that these gases play a role in signal transduction, modulating physiological function.\\u000a The roles of these gases are complex

D. Jeannean Carver; Lisa A. Palmer

201

Effects of Lime and Carbonate of Lime on Acid Phosphate.  

E-print Network

phosphate. AcL 0.1 grzm calcium carbonate mixed with the acid phosphate be- fore putting in the soil. One gram sulphate of potash and 1 gram ammonium nitrate added to all pots. Corn pIanted May S, harvested Julv 10-14, 1911. Four stalks. One gram... .................. ' 1,ah. No. 3653 3653 .0004 0015 0 .0433 .0113 4604 1 -AC corn. .................... ........................... 2-AC. 3-ACL ........................... ........................... 4-ACL I-AC sorghum. ........... : .... 2-AC...

Fraps, G. S. (George Stronach)

1917-01-01

202

Activated carbon passes tests for acid-gas cleanup  

Microsoft Academic Search

Use of activated carbon to remove hydrocarbon contaminants from the acid-gas feed to Claus sulfur-recovery units has been successfully pilot tested in Saudi Arabia. Pilot plant results are discussed here along with issues involved in scale-up to commercial size. Heavy hydrocarbons, particularly benzene, toluene, and xylene (BTX) have been linked to coke formation and catalyst deactivation in Claus converters. This

L. G. Harruff; S. J. Bushkuhl

1996-01-01

203

Production of sulfur gases and carbon dioxide by synthetic weathering of crushed drill cores from the Santa Cruz porphyry copper deposit near Casa Grande, Pinal County, Arizona  

USGS Publications Warehouse

Samples of ground drill cores from the southern part of the Santa Cruz porphyry copper deposit, Casa Grande, Arizona, were oxidized in simulated weathering experiments. The samples were also separated into various mineral fractions and analyzed for contents of metals and sulfide minerals. The principal sulfide mineral present was pyrite. Gases produced in the weathering experiments were measured by gas chromatography. Carbon dioxide, oxygen, carbonyl sulfide, sulfur dioxide and carbon disulfide were found in the gases; no hydrogen sulfide, organic sulfides, or mercaptans were detected. Oxygen concentration was very important for production of the volatiles measured; in general, oxygen concentration was more important to gas production than were metallic element content, sulfide mineral content, or mineral fraction (oxide or sulfide) of the sample. The various volatile species also appeared to be interactive; some of the volatiles measured may have been formed through gas reactions. ?? 1990.

Hinkle, M.E.; Ryder, J.L.; Sutley, S.J.; Botinelly, T.

1990-01-01

204

REACTIONS OF CHLORITE WITH ACTIVATED CARBON AND WITH VANILLIC ACID AND INDAN ADSORBED ON ACTIVATED CARBON  

EPA Science Inventory

The reaction between chlorite (CO2(-1)) and vanillic acid, at pH 6.0 in the presence of granular activated carbon (GAC), yielded several reaction products identifiable by GC/MS; no products were found in the absence of GAC. Indan and ClO2 or ClO2(-1) reacted in aqueous solution a...

205

Abundance and isotope systematics of carbon in subglacial basalts, geothermal gases and fluids from Iceland's rift zones  

NASA Astrophysics Data System (ADS)

P. H. BARRY1*, D. R. HILTON1, E. FÜRI1, S.A. HALLDÓRSON1, T.P. FISCHER2, K. GRONVOLD3 1 Scripps Institution of Oceanography, UCSD, La Jolla, California 92093, USA (*Correspondence: pbarry@ucsd.edu). 2University of New Mexico, Albuquerque, NM 87131, USA. 3University of Iceland, Askja, Sturlugata 7, IS-101, Reykjavik, Iceland Carbon dioxide (CO2) is the dominant non-aqueous volatile species found in oceanic basalts and geothermal fluids and serves as the carrier gas for trace volatiles such as He and other noble gases. The aim of this study is to identify the superimposed effects of degassing and crustal contamination on the CO2 systematics of the Icelandic hotspot in order to reveal and characterize the carbon abundance and isotopic features of the underlying mantle source. Our approach involves coupling CO2 with He, utilizing the sensitivity of 3He/4He ratios to reveal mantle and crustal inputs. We report new C-isotope (?13C) and abundance characteristics for a suite of 47 subglacial basalts and 50 geothermal gases and fluids from Iceland. CO2 contents in hyaloclastite glasses are extremely low (10-100 ppm) and likely residual following extensive degassing whereas geothermal fluids are dominated by CO2 (>90 %). C-isotopes range from -27.2 to -3.6 ‰ (vs. PDB) for basalts and from -18.8 to 2.86 ‰ (vs. PDB) for geothermal samples (mean = -4.2 ± 3.6 ‰). CO2/3He ratios range from 108 to 1012 for basalts and from 105 to 1012 for geothermal samples: In both cases, our results extend He-CO2 relationships over a much broader range than reported previously [1]. Taken together, these data suggest that several processes including mixing, degassing, and/or syn- or post-eruptive crustal contamination may act to modify CO2 source characteristics. Equilibrium degassing models are compatible with ~75 % of the basalt data, and preliminary results indicate that initial Icelandic source characteristics are ~500 ppm CO2 and ?13C ~ -5 ‰ (vs. PDB). These values are high compared to N-MORB mantle source estimates (72-134 ppm) based upon CO2/Nb ratios [2, 3]; however, they are in good agreement with those from submarine glasses on adjacent segments from the Reykjanes and Kolbeinsey ridges [4,5]. Significantly, the model-derived ?13C estimate is close to the mean Icelandic geothermal value, implying that fluids closely resemble source values, i.e. they likely represent the exsolved component. Integrating the estimated source CO2 content with magma production values of 0.079 km3/yr [6] yields a CO2 flux of ~1.2 x 1011 mol CO2 yr-1for Iceland, representing ~ 5.4 % of the total carbon ridge flux of 2.2 x 1012 mol CO2 yr-1 [7]. Thus, the average CO2 flux estimate for Iceland is ~2.2 x 108 mol CO2 yr-1km-1 strike of ridge axis, which compares to an overall ridge flux (including Iceland) of ~2.9 x 107 mol CO2 yr-1km-1. This difference highlights both heterogeneity in source volatile contents and magma production rates as important controls for determining mantle CO2 fluxes. [1] Poreda et al., 1992 [2] Saal et al., 2002. [3] Shaw et al., 2010. [4] de Leeuw, 2007 [5] Macpherson et al., 2005. [6] Thordarson et al., 2007 [7] Marty et al., 1998.

Barry, P. H.; Hilton, D. R.; Fueri, E.; Halldorsson, S. A.; Fischer, T. P.; Gronvold, K.

2010-12-01

206

Carbon nanoparticles with tosyl functional group for distinguishing voltammetric peaks of ascorbic acid and uric acid.  

PubMed

In this approach, electro-oxidation of a mixture of uric acid and ascorbic acid at the surface of tosyl surface carbon nanoparticles/glassy carbon electrode has been performed. The electro-oxidation of these compounds at bare electrode is sluggish and there is no suitable peak separation between them. However, using functionalized carbon nanoparticles, two well-defined anodic peaks with a considerable enhancement in the peak current and a remarkable peak potential separation near 452 mV is obtained. The porous interfacial layer of the carbon nanoparticles modified electrode with a high specific surface area increases the conductive area; molecules can penetrate through the conductive porous channels onto the electrode more easily so leading to higher sensitivity and selectivity. The dynamic linear ranges of 1.0 × 10(-5) to 3.0 × 10(-3)M and 1.0 × 10(-7) to 1.0 × 10(-4)M with detection limits 1.0 × 10(-5)M and 2.0 × 10(-8)M (for S/N=3) were obtained for ascorbic acid and uric acid, respectively. Analytical utility of the modified electrode has been examined successfully using human urine samples and vitamin C commercial tablets. PMID:25492188

Amiri, Mandana; Imanzadeh, Hamideh; Banaei, Alireza

2015-02-01

207

Biosynthesis of 2-hydroxyisobutyric acid (2-HIBA) from renewable carbon.  

PubMed

Nowadays a growing demand for green chemicals and cleantech solutions is motivating the industry to strive for biobased building blocks. We have identified the tertiary carbon atom-containing 2-hydroxyisobutyric acid (2-HIBA) as an interesting building block for polymer synthesis. Starting from this carboxylic acid, practically all compounds possessing the isobutane structure are accessible by simple chemical conversions, e. g. the commodity methacrylic acid as well as isobutylene glycol and oxide. During recent years, biotechnological routes to 2-HIBA acid have been proposed and significant progress in elucidating the underlying biochemistry has been made. Besides biohydrolysis and biooxidation, now a bioisomerization reaction can be employed, converting the common metabolite 3-hydroxybutyric acid to 2-HIBA by a novel cobalamin-dependent CoA-carbonyl mutase. The latter reaction has recently been discovered in the course of elucidating the degradation pathway of the groundwater pollutant methyl tert-butyl ether (MTBE) in the new bacterial species Aquincola tertiaricarbonis. This discovery opens the ground for developing a completely biotechnological process for producing 2-HIBA. The mutase enzyme has to be active in a suitable biological system producing 3-hydroxybutyryl-CoA, which is the precursor of the well-known bacterial bioplastic polyhydroxybutyrate (PHB). This connection to the PHB metabolism is a great advantage as its underlying biochemistry and physiology is well understood and can easily be adopted towards producing 2-HIBA. This review highlights the potential of these discoveries for a large-scale 2-HIBA biosynthesis from renewable carbon, replacing conventional chemistry as synthesis route and petrochemicals as carbon source. PMID:20184738

Rohwerder, Thore; Müller, Roland H

2010-01-01

208

Acid dew and the role of chemistry in the dry deposition of reactive gases to wetted surfaces  

NASA Technical Reports Server (NTRS)

A formalism is developed to describe the dry deposition of soluble reactive gases to wetted surfaces in terms of the relevant meteorological conditions, the surface roughness, the total amount of liquid water present on the surface, the rate of accumulation of this water, and the species' solubility and reactivity in the surface water. This formulation is then incorporated into a model designed to simulate the generation of acidic dew from the deposition of HNO3, SO2, S(IV) oxidants, H2O2, and O3. Similar to the observations of dew in the continental U.S., the model generates a dewdrop pH of about 4 by the end of the night; the pH can rapidly fall to toxic levels due to rapid evaporation after sunrise. Relatively low deposition velocities are predicted for the SO2 and O3 because of their lower solubilities and hence larger surface resistances than those of the other oxidants. Because the chemical lifetime of the SO2 in the dew is influenced by the atmospheric levels of H2O2, O3, and SO2, the SO2 deposition velocity is a strong function of these species' atmospheric abundances.

Chameides, William L.

1987-01-01

209

Effects of flow rate and starvation of reactant gases on the performance of phosphoric acid fuel cells  

NASA Astrophysics Data System (ADS)

Effects of reactant gas flow rates and starvation on the performance of phosphoric acid fuel cells were studied using single cells. As the reactant gas flow rates of single cell increased, the performance of the cell increased, and then remained constant. The optimum flow rates of hydrogen, oxygen and air under cell operating condition of 150 mA/cm 2 at 190°C were found to be 5 cc/min·cm 2, 5 cc/min·cm 2, and 15 cc/min·cm 2 at 1 atm and room temperature, respectively. The open circuit voltage of the single cell decreased with increasing oxygen flow rate at constant hydrogen flow rate, which is attributed to the increased gas cross-over rate. When the reactant gases were again supplied to the cell after gas starvation, the cell voltage losses were found to be about 5 mV in the case of hydrogen starvation and about 1 mV for oxygen starvation, and the voltage loss was independent of gas starvation time. These results were discussed from the electrochemical viewpoint of the cell.

Song, Rak-Hyun; Kim, Chang-Soo; Shin, Dong Ryul

210

Amino acids of the Murchison meteorite. II - Five carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids  

NASA Technical Reports Server (NTRS)

The five-carbon acyclic primary beta, gamma, and delta amino alkanoic acids of the Murchison meteorite are studied using gas chromatography-mass spectrometry and ion exchange chromatography. The chromatograms reveal that alpha is the most abundant monoamino alkanoic acid followed by gamma and beta, and an exponential increase in the amount of amino acid is observed as the carbon number increases in the homologous series. The influence of frictional heating, spontaneous thermal decomposition, and radiation of the synthesis of amino acids is examined. The data obtained support an amino acid synthesis process involving random combination of single-carbon precursors.

Cronin, J. R.; Pizzarello, S.; Yuen, G. U.

1985-01-01

211

Black Carbon in Sedimentary Organic Carbon in the Northeast Pacific using the Benzene Polycarboxylic Acid Method  

NASA Astrophysics Data System (ADS)

Black carbon (BC) in the Northeast Pacific ultrafiltered dissolved organic matter (UDOM) was found to be surprisingly old with a 14C age of 18,000 +/-3,000 14C years (Ziolkowski and Druffel, 2010) using the Benzene Polycarboxylic Acid (BPCA) method, while BC in sedimentary organic carbon (SOC) was found to be 2,400-12,900 14C years older than non-BC SOC (Masiello and Druffel, 1998) with a different method. Using the dichromate-sulfuric acid oxidation method (Wolbach and Anders, 1989), Masiello and Druffel (1998) estimated that 12-31% of SOC in the Northeast Pacific and the Southern Ocean surface sediments was black carbon (BC). However, the dichromate-sulfuric acid oxidation may over-estimate the concentration of BC, because this method is more biased toward modern (char) material (Currie et al., 2002). Alternatively, the BPCA method isolates aromatic components of BC as benzene rings substituted with carboxylic acid groups, and provides structural information about the BC. Recent modifications to the BPCA method by Ziolkowski and Druffel (2009) involve few biases in quantifying BC in the continuum between char and soot in UDOM. Here we use the BPCA method to determine the concentrations and 14C values of BC in sediments from three sites in the Northeast Pacific Ocean. Constraining the difference between non-BC SOC and BC-SOC using the BPCA method allows for a more precise estimate of how much BC is present in the sediments and its 14C age. Presumably, the intermediate reservoir of BC is oceanic dissolved organic carbon (DOC) and is, in part, responsible for DOC’s great 14C age. These results can be utilized to better constrain the oceanic carbon budget as a possible sink of BC. References: Currie, L. A., Benner Jr., B. A., Kessler, J.D., et al (2002), A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, nist srm 1649a, J. Res. Natl. Inst. Stand. Technol., 107, 279-298. Masiello, C., and E. R. Druffel (1988), Black carbon in deep-sea sediments, Science, 280, 1911-1913. Wolbach, W., and E. Anders (1989), Elemental carbon in sediments: Determination and isotopic analysis in presence of kerogen, Geochim. Cosmochim. Acta, 53, 1637-1647. Ziolkowski, L. A., and E. R. Druffel (2010), Aged black carbon identified in marine dissolved organic carbon, J. Geophys. Res., 37, L16601, doi: 10.1029/2010GL043963.

Coppola, A. I.; Ziolkowski, L. A.; Druffel, E. R.

2010-12-01

212

Helium and carbon isotope systematics of Rungwe geothermal gases and fluids; southern Tanzania  

NASA Astrophysics Data System (ADS)

P. H. BARRY1*, D. R. HILTON1, T. P. FISCHER2, J. M. DE MOOR2, F. MANGASINI3 C. RAMIREZ4 1 Geosciences Research Division, Scripps Institution of Oceanography, UCSD, La Jolla, California 92093-0244, USA (*Correspondence: pbarry@ucsd.edu) 2 Department of Earth and Planetary Sciences, MSC 03 2040, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA. 3 Department of Mining and Mineral Processing Engineering, University of Dar Es Salaam, PO Box 35131, Dar Es Salaam, Tanzania. 4 Centro de Investigaciones en Ciencias Geologicas, Escuela Centroamericana de Geologia, Universidad de Costa Rica. The East African Rift (EAR) is the largest modern example of continental rifting, extending from the Afar depression in the north to the Rungwe region in southern Tanzania. EAR volcanism is attributed to the presence of one or more mantle plumes [1]. Late Miocene to recent volcanism and geothermal activity mark the Rungwe region [2], with mafic eruptions as recently as 200 years ago. Our aim is to delineate the southern geographical extent of plume influence on the propagating EAR by investigating the He-CO2 characteristics of geothermal fluids in the Rungwe region. We report new helium (He) and carbon (C) isotopes (3He/4He, ?13C) and relative abundance (CO2/3He) characteristics for a suite of 20 geothermal gas and fluid samples from 11 different localities in the Rungwe region. He-isotopes are in good agreement with previous reports [3], and range from ~1 RA to ~7 RA (MORB-like values), indicating admixture between upper mantle He and variable proportions of radiogenic He. C-isotopes ranges from -2.8 to -6.5 ‰ (vs. PDB) with all falling in the MORB range (~4.5 ± 2‰). CO2/3He ratios vary over 5 orders of magnitude from ~3 x 10^9 (MORB-like) to higher values (up to ~3 x 10^13) normally associated with crustal lithologies. Taken together, the He-CO2 data can be explained by 2-component mixing of a deep-seated mantle source with crustal component(s). There are no observed latitudinal isotopic trends in He-CO2. However, the two localities with MORB-like 3He/4He ratios ~6 to 7 RA, ?13C ~ -4 to -5 ‰ and CO2/3He ~ 4 x10^9 are both cold temperature (~ 15°C) CO2 gas vents. The MORB-like characteristics of these cold vents are comparable to MORB-like values observed at Oldoinyo Lengai in northern Tanzania [4], suggesting that both Rungwe region and Oldoinyo Lengai may derive their volatile compositions from a homogeneous (MORB-like) mantle source common to the entire segment of the southern EAR. [1] Furman (2007) Journal of African Earth Sciences 48, 147-160. [2] Ebinger et al. (1989) Journal of Geophysical Research 94, 15,785-15,803. [3] Pik et al. (2006) Chemical Geology 226, 100-114. [4] Fisher et al. (2009) Nature 459, 77-80.

Barry, P. H.

2009-12-01

213

Parallel-plate wet denuder coupled ion chromatograph for near-real-time detection of trace acidic gases in clean room air.  

PubMed

This paper describes the performance of our automated acidic (CH(3)COOH, HCOOH, HCl, HNO(2), SO(2), and HNO(3)) gases monitor utilizing a parallel-plate wet denuder (PPWD). The PPWD quantitatively collects gaseous contaminants at a high sample flow rate (?8 dm(3) min(-1)) compared to the conventional methods used in a clean room. Rapid response to any variability in the sample concentration enables near-real-time monitoring. In the developed monitor, the analyte collected with the PPWD is pumped into one of two preconcentration columns for 15 min, and determined by means of ion chromatography. While one preconcentration column is used for chromatographic separation, the other is used for loading the sample solution. The system allows continuous monitoring of the common acidic gases in an advanced semiconductor manufacturing clean room. PMID:21828917

Takeuchi, Masaki; Tsunoda, Hiromichi; Tanaka, Hideji; Shiramizu, Yoshimi

2011-01-01

214

Deterministic modeling of the corrosion of a low-carbon steel by carbon dioxide and the effect of acetic acid  

Microsoft Academic Search

The current work is carried out with the aim of developing a deterministic model of the corrosion of low-carbon steel by carbon dioxide including the effect of acetic acid. The interaction of acetic acid with the corrosion-products layer is studied and the system is modelled by considering reactions and the transport processes within the boundary layer along with protective film

Omar Rosas-Camacho

2010-01-01

215

Synthesis of acid-functionalized composite via surface deposition of acid-containing amorphous carbon  

NASA Astrophysics Data System (ADS)

A synthetic procedure, including two steps: a hydrothermal treatment using H2SO4 solution and a thermal treatment with concentrated H2SO4 in Teflon-lined stainless autoclaves was developed to synthesize acid-functionalized composite. In this process, the carbonization of glucose which contributed to the formation of carbon species with acid functional groups occurred on the silica surface. The resultant composite, investigated by powder XRD, low temperature N2 sorption and TEM, possessed well-defined mesostructure. And it was determined by XPS that amorphous carbon was deposited at the silica surface of SBA-15. The presence of multi-functional groups in the composite was confirmed by FT-IR results. Furthermore, carboxylic and sulfonic groups could be incorporated into the composite material via the covalent bond. The composite was employed as the catalyst for the acetalization of carbonyl compounds. It was suggested that acid sites were well dispersed, which was responsible for the good performance in the catalytic test. According to these facts, a synthesis route for mesostructured composite with acid functional groups has been proposed.

Du, Bin; Zhang, Xuan; Lou, Lan-Lan; Dong, Yanling; Liu, Gaixia; Liu, Shuangxi

2012-07-01

216

Stable carbon isotopic compositions of bacterial fatty acids in a seagrass dominated system  

E-print Network

. The stable carbon isotope ratios ([ð]¹³C) of branched chain fatty acids, iso- and anteiso-15:0 (i&a15:0) found only in bacteria were used to assess carbon utilization. The [ð]¹³C of total organic carbon (TO¹³C) and the ubiquitous fatty acid 16:0 were used...

Jones, Walter Brian

2001-01-01

217

Electrochemical determination of glycoalkaloids using a carbon nanotubes-phenylboronic acid modified glassy carbon electrode.  

PubMed

A versatile strategy for electrochemical determination of glycoalkaloids (GAs) was developed by using a carbon nanotubes-phenylboronic acid (CNTs-PBA) modified glassy carbon electrode. PBA reacts with ?-solanine and ?-chaconine to form a cyclic ester, which could be utilized to detect GAs. This method allowed GA detection from 1 ?M to 28 ?M and the detection limit was 0.3 ?M. Affinity interaction of GAs and immobilized PBA caused an essential change of the peak current. The CNT-PBA modified electrodes were sensitive for detection of GAs, and the peak current values were in quite good agreement with those measured by the sensors. PMID:24287539

Wang, Huiying; Liu, Mingyue; Hu, Xinxi; Li, Mei; Xiong, Xingyao

2013-01-01

218

Electrochemical Determination of Glycoalkaloids Using a Carbon Nanotubes-Phenylboronic Acid Modified Glassy Carbon Electrode  

PubMed Central

A versatile strategy for electrochemical determination of glycoalkaloids (GAs) was developed by using a carbon nanotubes-phenylboronic acid (CNTs-PBA) modified glassy carbon electrode. PBA reacts with ?-solanine and ?-chaconine to form a cyclic ester, which could be utilized to detect GAs. This method allowed GA detection from 1 ?M to 28 ?M and the detection limit was 0.3 ?M. Affinity interaction of GAs and immobilized PBA caused an essential change of the peak current. The CNT-PBA modified electrodes were sensitive for detection of GAs, and the peak current values were in quite good agreement with those measured by the sensors. PMID:24287539

Wang, Huiying; Liu, Mingyue; Hu, Xinxi; Li, Mei; Xiong, Xingyao

2013-01-01

219

NOBLE GASES  

EPA Science Inventory

The Noble Gases symposium, on which this report is based, provided comprehensive coverage of the noble gases. The coverage included, but was not limited to, the properties, biokinetics, bioeffects, production and release to the environment, detection techniques, standards, and ap...

220

Carbon isotope fractionation in phospholipid fatty acid biomarkers of bacteria and fungi native to an acid mine drainage lake  

Microsoft Academic Search

This study identifies isotope signatures associated with autotrophic and heterotrophic microbial communities that may provide a means to determine carbon cycling relationships in situ for acid mine drainage (AMD) sites. Stable carbon isotope ratios (?13C) of carbon sources, bulk cells, and membrane phospholipids (PLFA) were measured for autotrophic and heterotrophic microbial enrichment cultures from a mine tailings impoundment in northern

Benjamin R. Cowie; Gregory F. Slater; Luc Bernier; Lesley A. Warren

2009-01-01

221

Bias-dependent amino-acid-induced conductance changes in short semi-metallic carbon nanotubes  

E-print Network

Bias-dependent amino-acid-induced conductance changes in short semi-metallic carbon nanotubes G the interaction between short semi-metallic carbon nanotubes and different amino acids using molecular dynamics different mechanisms of nanotube-conductance-change upon adsorption of amino acids: one due to the change

Pulfrey, David L.

222

Isotopic fractionations associated with phosphoric acid digestion of carbonate minerals: Insights from first-principles theoretical  

E-print Network

Isotopic fractionations associated with phosphoric acid digestion of carbonate minerals: Insights 27 May 2009; available online 23 June 2009 Abstract Phosphoric acid digestion has been used with phosphoric acid digestion of carbonates at 25 °C are 10.72&, 0.220&, 0.137&, 0.593& for, respectively, 18 O

Goddard III, William A.

223

Modeling of Water-rock interaction in the Mackenzie Basin: competition between sulfuric and carbonic acids  

E-print Network

sulfuric and carbonic acids E. Beaulieu, Y. Godd´eris, D. Labat, C. Roelandt, D. Calmels, J. Gail- lardet in the Mackenzie Basin: competition between sulfuric and carbonic acids. E. Beaulieu1 , Y. Goddéris1 , D. Labat1, a simulation is performed removing the contribution of sulfuric acid to the weathering system. The main

224

The application of activated carbon enhanced lime for controlling acid gases, mercury, and dioxins from MWCs  

Microsoft Academic Search

Environmental control agencies have sought to reduce Municipal Waste Combustor (MWC) emission rates by the implementation of new regulations. Examples of these regulations are Germany`s 17th Federal Regulation on Emission Protection; the Clean Air Act Amendments of 1990; EPA`s New Source Performance Standards (NSPS) and Emission Guidelines; and recent regulatory actions in Minnesota, New Jersey, and Florida to adopt Hg

A. Licata; M. Babu; W. Carlson

1996-01-01

225

Determination of the acidic sites of purified single-walled carbon nanotubes by acid–base titration  

Microsoft Academic Search

We report the measurement of the acidic sites in three different samples of commercially available full-length purified single-walled carbon nanotubes (SWNTs) – as obtained from CarboLex (CLI), Carbon Solutions (CSI) and Tubes@Rice (TAR) – by simple acid–base titration methods. Titration of the purified SWNTs with NaOH and NaHCO3 solutions was used to determine the total percentage of acidic sites and

H. Hu; P Bhowmik; B Zhao; M. A Hamon; M. E Itkis; R. C Haddon

2001-01-01

226

Elevated carbon dioxide increases salicylic acid in Glycine max.  

PubMed

Concentrations of carbon dioxide (CO(2)) are increasing in the atmosphere, affecting soybean (Glycine max L.) phytohormone signaling and herbivore resistance. Whether the impact of elevated CO(2) on phytohormones and induced defenses is a generalized response within this species is an open question. We examined jasmonic acid (JA) and salicylic acid (SA) under ambient and elevated CO(2) concentrations with and without Japanese beetle (Popillia japonica Newman) damage and artificial damage across six soybean cultivars (HS93-4118, Pana, IA 3010, Loda, LN97-15076, and Dwight). Elevated CO(2) reduced constitutive levels of JA and related transcripts in some but not all soybean cultivars. In contrast to the variation in JA, constitutive levels of salicylic were increased universally among soybean cultivars grown under elevated CO(2). Variation in hormonal signaling may underpin observed variation in the response of insect herbivores and pathogens to plants grown under elevated CO(2). PMID:23321090

Casteel, Clare L; Segal, Lauren M; Niziolek, Olivia K; Berenbaum, May R; DeLucia, Evan H

2012-12-01

227

A bio-inspired two-layer sensing structure of polypeptide and multiple-walled carbon nanotube to sense small molecular gases.  

PubMed

In this paper, we propose a bio-inspired, two-layer, multiple-walled carbon nanotube (MWCNT)-polypeptide composite sensing device. The MWCNT serves as a responsive and conductive layer, and the nonselective polypeptide (40 mer) coating the top of the MWCNT acts as a filter into which small molecular gases pass. Instead of using selective peptides to sense specific odorants, we propose using nonselective, peptide-based sensors to monitor various types of volatile organic compounds. In this study, depending on gas interaction and molecular sizes, the randomly selected polypeptide enabled the recognition of certain polar volatile chemical vapors, such as amines, and the improved discernment of low-concentration gases. The results of our investigation demonstrated that the polypeptide-coated sensors can detect ammonia at a level of several hundred ppm and barely responded to triethylamine. PMID:25751078

Wang, Li-Chun; Su, Tseng-Hsiung; Ho, Cheng-Long; Yang, Shang-Ren; Chiu, Shih-Wen; Kuo, Han-Wen; Tang, Kea-Tiong

2015-01-01

228

The Effect of Temperature and Acid Concentration on Corrosion of Low Carbon Steel in Hydrochloric Acid Media  

Microsoft Academic Search

Problem statement: The effect of different temperatures and acid conc entrations on the corrosion of low carbon steel in hydrochloric acid were addressed in this study. Approach: The effect of temperature was explained by application of Arrhenius equation and transition state theory, while the acid concentration effect was explained u sing reaction kinetic equations. The combined effect of temperature and

Anees A. Khadom; Aprael S. Yaro; Abdul Amir; H. Kadum; Ahmed S. AlTaie

2009-01-01

229

Hydrogen storage and delivery: the carbon dioxide - formic acid couple.  

PubMed

Carbon dioxide and the carbonates, the available natural C1 sources, can be easily hydrogenated into formic acid and formates in water; the rate of this reduction strongly depends on the pH of the solution. This reaction is catalysed by ruthenium(II) pre-catalyst complexes with a large variety of water-soluble phosphine ligands; high conversions and turnover numbers have been realised. Although ruthenium(II) is predominant in these reactions, the iron(II) - tris[(2-diphenylphosphino)-ethyl]phosphine (PP3) complex is also active, showing a new perspective to use abundant and inexpensive iron-based compounds in the CO2 reduction. In the catalytic hydrogenation cycles the in situ formed metal hydride complexes play a key role, their structures with several other intermediates have been proven by multinuclear NMR spectroscopy. In the other hand safe and convenient hydrogen storage and supply is the fundamental question for the further development of the hydrogen economy; and carbon dioxide has been recognised to be a viable H2 vector. Formic acid--containing 4.4 weight % of H2, that is 53 g hydrogen per litre--is suitable for H2 storage; we have shown that in aqueous solutions it can be selectively decomposed into CO-free (CO < 10 ppm) CO2 and H2. The reaction takes place under mild experimental conditions and it is able to generate high pressure H2 (up to 600 bar). The cleavage of HCOOH is catalysed by several hydrophilic Ru(II) phosphine complexes (meta-trisulfonated triphenylphosphine, mTPPTS, being the most efficient one), either in homogeneous systems or as immobilised catalysts. We have also shown that the iron(II)--hydrido tris[(2-diphenylphosphino)ethyl]phosphine complex catalyses with an exceptionally high rate and efficiency (turnover frequency, TOF = 9425 h(-1)mol(-1); turnover number, TON = 92400) the formic acid cleavage, in environmentally friendly propylene carbonate solution, opening the way to use cheap, non-noble metal based catalysts for this reaction, too. PMID:22026175

Laurenczy, Gábor

2011-01-01

230

Amino acids of the Murchison meteorite. I - Six carbon acyclic primary alpha-amino alkanoic acids  

NASA Technical Reports Server (NTRS)

Six of the seven chain isomers of six-carbon acyclic primary alpha-amino alkanoic acids (leucine isomers) have been either identified or confirmed in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography. 2-Amino-2-ethylbutyric acid, 2-amino-2,3-dimethylbutyric acid, pseudoleucine, and 2-methylnorvaline were positively identified by GC-MS. These amino acids have not been previously reported to occur in natural materials and may be uniquely meteoritic in origin. The presence of leucine and isoleucine (including the diastereoisomer, alloisoleucine) was confirmed. Peaks corresponding to norleucine were seen by ion-exchange and gas chromatography but characteristic mass spectra were not obtained. The alpha-branched chain isomers in this series are quantitatively the most significant. These results are compared with literature data on amino acid synthesis by electrical discharge and Fischer-Tropsch-type catalysis. Neither model system produces an amino acid suite that is completely comparable to that found in the Murchison meteorite.

Cronin, J. R.; Gandy, W. E.; Pizzarello, S.

1981-01-01

231

Differential effects of insulin signaling on individual carbon fluxes for fatty acid synthesis in brown adipocytes  

E-print Network

Considering the major role of insulin signaling on fatty acid synthesis via stimulation of lipogenic enzymes, differential effects of insulin signaling on individual carbon fluxes for fatty acid synthesis have been ...

Yoo, Hyuntae

232

40 CFR 600.108-08 - Analytical gases.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Analytical gases. 600.108-08 Section 600... FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related... § 600.108-08 Analytical gases. The analytical gases...

2012-07-01

233

40 CFR 600.108-08 - Analytical gases.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Analytical gases. 600.108-08 Section 600... FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related... § 600.108-08 Analytical gases. The analytical gases...

2013-07-01

234

40 CFR 600.108-78 - Analytical gases.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Analytical gases. 600.108-78 Section 600...CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy Regulations... § 600.108-78 Analytical gases. The analytical gases for all fuel economy testing...

2010-07-01

235

40 CFR 600.108-78 - Analytical gases.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Analytical gases. 600.108-78 Section 600...CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and... § 600.108-78 Analytical gases. The analytical gases for all fuel economy testing...

2011-07-01

236

Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents  

SciTech Connect

The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (particle size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a filter house and the filter disk with a filter cake, operating continuously, simulating filter cake build-up and cleaning of the filter medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from zero to 20 vol%. The experimental program with NaHCO{sub 3} is listed in Table 1. In addition, model calculations were carried out based on own and published experimental results that estimate residence time and temperature effects on removal efficiencies.

Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.

2002-09-20

237

Water-soluble organic carbon, dicarboxylic acids, ketoacids, and ?-dicarbonyls in the tropical Indian aerosols  

Microsoft Academic Search

Tropical aerosol (PM10) samples (n = 49) collected from southeast coast of India were studied for water-soluble dicarboxylic acids (C2–C12), ketocarboxylic acids (C2–C9), and ?-dicarbonyls (glyoxal and methylglyoxal), together with analyses of total carbon (TC) and water-soluble organic carbon (WSOC). Their distributions were characterized by a predominance of oxalic acid followed by terephthalic (t-Ph), malonic, and succinic acids. Total concentrations

Chandra Mouli Pavuluri; Kimitaka Kawamura; T. Swaminathan

2010-01-01

238

Poly(carbonate ester)s Based on Units of 6-Hydroxyhexanoic Acid and Glycerol  

E-print Network

(trimethylene carbon- ate), and most notably poly(glycolic acid) and poly(lactic acid), have met wide acceptance or succinic acids have also been reported.20 Poly( -caprolactone) is one polymer that has been used widely- lactone) is because of its slow degradation rate which does not create acidic microenvironments like poly(glycolic

239

Carbonic Acid by Ion Implantation in Water_solarCarbon Dioxide Ice Mixtures  

NASA Astrophysics Data System (ADS)

We present the results of experiments performed by keV ion (He and H) bombardment of frozen mixtures of H 2O:CO 2and of pure CO 2ice. Using keV He ions we confirm the already reported measurement of carbonic acid (H 2CO 3) production in an ice mixture of frozen water and carbon dioxide (1:1) after irradiation by 0.7 MeV H ions (Moore, M. H., and R. K. Khanna 1991. Spectrochim. Acta47, 255-262; Moore, M. H., R. K. Khanna, and B. Donn 1991. J. Geophys. Res. E96(2), 17,541-17,545.). Contrary to a previous report (Pirronello, V., W. L. Brown, L. J. Lanzerotti, K. J. Marcantonio, and E. H. Simmons 1982. Astrophys. J.262, 636-640.), formaldehyde (H 2CO), if any, is not a major product. Implantation with hydrogen ions demonstrates that carbonic acid is formed even if the irradiated target is pure CO 2; i.e., the implanted ion is incorporated into the target and forms new bonds. Some possible astrophysical applications on Solar System objects or (pre-solar) interstellar grains are discussed.

Brucato, J. R.; Palumbo, M. E.; Strazzulla, G.

1997-01-01

240

Electronegative gases  

SciTech Connect

Recent knowledge on electronegative gases essential for the effective control of the number densities of free electrons in electrically stressed gases is highlighted. This knowledge aided the discovery of new gas dielectrics and the tailoring of gas dielectric mixtures. The role of electron attachment in the choice of unitary gas dielectrics or electronegative components in dielectric gas mixtures, and the role of electron scattering at low energies in the choice of buffer gases for such mixtures is outlined.

Christophorou, L.G.

1981-01-01

241

Visible-light photoconversion of carbon dioxide into organic acids in an aqueous solution of carbon dots.  

PubMed

Carbon "quantum" dots (or carbon dots) have emerged as a new class of optical nanomaterials. Beyond the widely reported bright fluorescence emissions in carbon dots, their excellent photoinduced redox properties that resemble those found in conventional semiconductor nanostructures are equally valuable, with photon-electron conversion applications from photovoltaics to CO2 photocatalytic reduction. In this work we used gold-doped carbon dots from controlled synthesis as water-soluble catalysts for a closer examination of the visible-light photoconversion of CO2 into small organic acids, including acetic acid (for which the reduction requires many more electrons than that for formic acid) and, more interestingly, for the significantly enhanced photoconversion with higher CO2 pressures over an aqueous solution of the photocatalysts. The results demonstrate the nanoscale semiconductor-equivalent nature of carbon dots, with excellent potential in energy conversion applications. PMID:24972094

Sahu, Sushant; Liu, Yamin; Wang, Ping; Bunker, Christopher E; Fernando, K A Shiral; Lewis, William K; Guliants, Elena A; Yang, Fan; Wang, Jinping; Sun, Ya-Ping

2014-07-22

242

Greenhouse Gases: A Closer Look  

NSDL National Science Digital Library

This lesson covers different aspects of the major greenhouse gases - water vapor, carbon dioxide, methane, nitrous oxides and CFCs - including some of the ways in which human activities are affecting the atmospheric concentrations of these key greenhouse gases. This is lesson six in a nine-lesson module about climate change.

King's Centre for Visualization in Science

243

Voluntary Reporting of Greenhouse Gases  

EIA Publications

The Voluntary Reporting of Greenhouse Gases Program was suspended May 2011. It was a mechanism by which corporations, government agencies, individuals, voluntary organizations, etc., could report to the Energy Information Administration, any actions taken that have or are expected to reduce/avoid emissions of greenhouse gases or sequester carbon.

2011-01-01

244

Starch saccharification by carbon-based solid acid catalyst  

NASA Astrophysics Data System (ADS)

The hydrolysis of cornstarch using a highly active solid acid catalyst, a carbon material bearing SO 3H, COOH and OH groups, was investigated at 353-393 K through an analysis of variance (ANOVA) and an artificial neural network (ANN). ANOVA revealed that reaction temperature and time are significant parameters for the catalytic hydrolysis of starch. The ANN model indicated that the reaction efficiency reaches a maximum at an optimal condition (water, 0.8-1.0 mL; starch, 0.3-0.4 g; catalyst, 0.3 g; reaction temperature, 373 K; reaction time, 3 h). The relationship between the reaction and these parameters is discussed on the basis of the reaction mechanism.

Yamaguchi, Daizo; Hara, Michikazu

2010-06-01

245

Sorption of boric acid and borax by activated carbon impregnated with various compounds  

Microsoft Academic Search

The separation of boron compounds, boric acid and borax from aqueous solution by activated carbon before and after impregnation with various compounds was studied. A series of activated carbons was prepared from coconut shell impregnated with calcium and barium chlorides, citric and tartaric acids. The examined processes were performed in batch and continuous systems under equilibrium and dynamic conditions. Impregnation

Lj. V. Rajakovi?; M. Dj. Risti?

1996-01-01

246

Improved acid neutralisation capacity assessment of iron carbonates by titration and theoretical calculation  

Microsoft Academic Search

The acid neutralisation capacity (ANC) of a rock sample containing significant amounts of Fe carbonates, as conducted to determine net acid production potential (NAPP), can be a difficult parameter to determine. Various ANC tests are available to determine the ANC of carbonates. This work does not attempt to create another ANC test protocol; rather, it provides a refinement for existing

P. A Weber; J. E Thomas; W. M Skinner; R. St. C Smart

2004-01-01

247

Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution  

DOEpatents

A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

Rau, Gregory Hudson

2014-07-01

248

Hydrophobic Catalysts For Removal Of NOx From Flue Gases  

NASA Technical Reports Server (NTRS)

Improved catalysts for removal of nitrogen oxides (NO and NO2) from combustion flue gases formulated as composites of vanadium pentoxide in carbon molecular sieves. Promotes highly efficient selective catalytic reduction of NOx at relatively low temperatures while not being adversely affected by presence of water vapor and sulfur oxide gases in flue gas. Apparatus utilizing catalyst of this type easily integrated into exhaust stream of power plant to remove nitrogen oxides, generated in combustion of fossil fuels and contribute to formation of acid rain and photochemical smog.

Sharma, Pramod K.; Hickey, Gregory S.; Voecks, Gerald E.

1995-01-01

249

Measurements of Acidic Gases and Aerosol Species Aboard the NASA DC-8 Aircraft During the Pacific Exploratory Mission in the Tropics (PEM-Tropics A)  

NASA Technical Reports Server (NTRS)

We received funding to provide measurements of nitric acid (HNO3), formic acid (HCOOH), acetic acid (CH3COOH), and the chemical composition of aerosols aboard the NASA Ames DC-8 research aircraft during the PEM-Tropics A mission. These measurements were successfully completed and the final data resides in the electronic archive (ftp-gte.larc.nasa.gov) at NASA Langley Research Center. For the PEM-Tropics A mission the University of New Hampshire group was first author of four different manuscripts. Three of these have now appeared in the Journal of Geophysical Research-Atmospheres, included in the two section sections on PEM-Tropics A. The fourth manuscript has just recently been submitted to this same journal as a stand alone paper. All four of these papers are included in this report. The first paper (Influence of biomass combustion emissions on the distribution of acidic trace gases over the Southern Pacific basin during austral springtime) describes the large-scale distributions of HNO3, HCOOH, and CH3COOH. Arguments were presented to show, particularly in the middle tropospheric region, that biomass burning emissions from South America and Africa were a major source of acidic gases over the South Pacific basin. The second paper (Aerosol chemical composition and distribution during the Pacific Exploratory Mission (PEM) Tropics) covers the aerosol aspects of our measurement package. Compared to acidic gases, O3, and selected hydrocarbons, the aerosol chemistry showed little influence from biomass burning emissions. The data collected in the marine boundary layer showed a possible marine source of NH3 to the troposphere in equatorial areas. This source had been speculated on previously, but our data was the first collected from an airborne platform to show its large-scale features. The third paper (Constraints on the age and dilution of Pacific Exploratory Mission-Tropics biomass burning plumes from the natural radionuclide tracer Pb-210) utilized the unexpectedly high concentrations of Pb-210 in the combustion plumes to estimate their ages and mixing along the transport route to the South Pacific basin. The final paper in the group (Tropospheric reactive-odd nitrogen over the South Pacific in austral springtime). This paper provides a summary of reactive nitrogen during PEM-Tropics A, with HNO3 and PAM showing the most impact from combustion emission.

Talbot, Robert W.; Dibb, Jack E.

1999-01-01

250

USE OF THE COMPOSITION AND STABLE CARBON ISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING  

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (Gamma 13C) of individual microbial phospholipid fatty acids (PLFAS) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SO...

251

Carbonate equilibria in hydrothermal systems: First ionization of carbonic acid in NaCl media to 300°C  

Microsoft Academic Search

The ionization quotients of aqueous carbon dioxide (carbonic acid) have been precisely determined in NaCl media to 5 m and from 50° to 300°C using potentiometric apparatus previously developed at Oak Ridge National Laboratory. The pressure coefficient was also determined to 250°C in the same media. These results have been combined with selected information in the literature and modeled in

C. S. Patterson; G. H. Slocum; R. H. Busey; R. E. Mesmer

1982-01-01

252

Separation of gases through gas enrichment membrane composites  

DOEpatents

Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.

Swedo, R.J.; Kurek, P.R.

1988-07-19

253

Separation of gases through gas enrichment membrane composites  

DOEpatents

Thin film composite membranes having as a permselective layer a film of a homopolymer of certain vinyl alkyl ethers are useful in the separation of various gases. Such homopolymers have a molecular weight of greater than 30,000 and the alkyl group of the vinyl alkyl monomer has from 4 to 20 carbon atoms with branching within the alkyl moiety at least at the carbon atom bonded to the ether oxygen or at the next adjacent carbon atom. These membranes show excellent hydrolytic stability, especially in the presence of acidic or basic gaseous components.

Swedo, Raymond J. (Mt. Prospect, IL); Kurek, Paul R. (Schaumburg, IL)

1988-01-01

254

Acid-base characteristics of organic carbon in the HUMEX Lake Skjervatjern  

SciTech Connect

The Humic Lake Acidification Experiment (HUMEX) was launched in 1988 to study the role of humic substances in the acidification of surface waters and the impacts of acidic deposition on the chemical and biological properties of humic substances. This subproject was designed to determine the contribution of organic acids to the acidity of Lake Skjervatjern (the HUMEX Lake) and the impacts of the acidification on the characteristics of organic carbon. In order to get an empirical measure for organic acidity, dissolved organic carbon (DOC) was fractionated, isolated, and base-titrated from each half of Lake Skjervatjern. Hydrophobic acids were the dominant organic carbon fraction; the total organic acid content was generally greater than 80% of the DOC. The reliability of the fractionation procedure was tested with synthetic acids and the Nordic Fulvic acid. The DOC fractions did not show high variation over the 1.5-y acidification period. Hydrophilic acids had consistently greater exchange acidities compared to hydrophobic acids, averaging 12.9 [mu]eq/mg DOC vs. 10.9 [mu]eq/mg DOC, respectively. The dissociation of organic acids during acid-base titrations clearly increased with increasing pH. The high organic anion contribution to the ion balances indicates that humic matter is an important acidity source in Lake Skjervatjern. There are slight signs that the contribution of organic acids to overall lake acidity has decreased since acidification was initiated. 22 refs., 5 figs., 1 tab.

Kortelainen, P.; David, M.B.; Roila, T.; Maekinen, I. (National Board of Waters and the Environment, Helsinki (Finland))

1992-01-01

255

The rate of carbonic acid decomposition in sea water and its oceanographic significance  

E-print Network

with and without the influence of atmospheric carbon dioxide based upon Buch's tables on the carbon dioxide and boric acid system in sea water are compared with exper- imental data obtained by the method of Mitchell and Rakestraw(1933) and Stoddard (1952... Mixtures of weak acids and their salts or of weak bases and their sa3ts are called buffer solutions, since they resist a change in pH upon addit1on oi' sli~ht amounts oi' acid or bases (Kolthoff', 1949). Sea water contairs carbonic and boric acids...

Park, Kilho

1957-01-01

256

Determination of tannic acid by adsorptive anodic stripping voltammetry at porous pseudo-carbon paste electrode  

Microsoft Academic Search

A novel and sensitive electrochemical sensor based on porous pseudo-carbon paste electrode (PPCPE) for tannic acid detection is described. PPCPE is fabricated by mixing calcium carbonate microspheres as the template, graphite powders as the filler, and pyrrole as the precursor of polymer which actually acted as the paste. After the polymerization of pyrrole catalyzed by Fe3+, the template calcium carbonate

Lijian Xu; Nongyue He; Jingjing Du; Yan Deng

2008-01-01

257

Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)  

USGS Publications Warehouse

Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side. Differences in microbial sulfate reduction, organic matter supply, and/or groundwater residence time likely contributed to this pattern. The contrasting features of the east and west sub-marsh zones highlight the need for multiple techniques for characterization of submarine groundwater discharge sources and the impact of biogeochemical processes on the delivery of nutrients and carbon to coastal areas via submarine groundwater discharge.

Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.

2014-01-01

258

Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)  

NASA Astrophysics Data System (ADS)

Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side. Differences in microbial sulfate reduction, organic matter supply, and/or groundwater residence time likely contributed to this pattern. The contrasting features of the east and west sub-marsh zones highlight the need for multiple techniques for characterization of submarine groundwater discharge sources and the impact of biogeochemical processes on the delivery of nutrients and carbon to coastal areas via submarine groundwater discharge.

Porubsky, W. P.; Weston, N. B.; Moore, W. S.; Ruppel, C.; Joye, S. B.

2014-04-01

259

Carbon and hydrogen isotopic characteristics of natural gases from the Luliang and Baoshan basins in Yunnan Province, China  

Microsoft Academic Search

The Luliang and Baoshan basins of Yunnan Province are two small-sized continental oil\\/gas-bearing sedimentary basins, which\\u000a were developed at the bases of the Carboniferous and Devonian systems during the Late Tertiary, covering an area of 325 km2 and 254 km2, respectively. Since the 1990s, there have been discovered small-sized natural gas pools in these two basins. The natural\\u000a gases are

Yongchang Xu; Wenhui Liu; Ping Shen; Wanchun Wang; Xiaofeng Wang; Tenger; Yaomin Yan; Ruobin Liu

2006-01-01

260

Thermal device and method for production of carbon monoxide and hydrogen by thermal dissociation of hydrocarbon gases  

DOEpatents

Carbon monoxide is produced in a fast quench reactor. The production of carbon monoxide includes injecting carbon dioxide and some air into a reactor chamber having a high temperature at its inlet and a rapidly expanding a reactant stream, such as a restrictive convergent-divergent nozzle at its outlet end. Carbon dioxide and other reactants such as methane and other low molecular weight hydrocarbons are injected into the reactor chamber. Other gas may be added at different stages in the process to form a desired end product and prevent back reactions. The resulting heated gaseous stream is then rapidly cooled by expansion of the gaseous stream.

Detering, Brent A. (Idaho Falls, ID); Kong, Peter C. (Idaho Falls, ID)

2001-01-01

261

The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black - Spill-over phenomenon and the important role of strong sites.  

PubMed

We analyse in detail our experimental data, our simulation results and data from the literature, for the adsorption of argon, nitrogen, carbon dioxide, methanol, ammonia and water on graphitized carbon black (GTCB), and show that there are two mechanisms of adsorption at play, and that their interplay governs how different gases adsorb on the surface by either: (1) molecular layering on the basal plane or (2) clustering around very strong sites on the adsorbent whose affinity is much greater than that of the basal plane or the functional groups. Depending on the concentration of the very strong sites or the functional groups, the temperature and the relative strength of the three interactions, (a) fluid-strong sites (fine crevices and functional group) (F-SS), (b) fluid-basal plane (FB) and (c) fluid-fluid (FF), the uptake of adsorbate tends to be dominated by one mechanism. However, there are conditions (temperature and adsorbate) where two mechanisms can both govern the uptake. For simple gases, like argon, nitrogen and carbon dioxide, adsorption proceeds by molecular layering on the basal plane of graphene, but for water which represents an extreme case of a polar molecule, clustering around the strong sites or the functional groups at the edges of the graphene layers is the major mechanism of adsorption and there is little or no adsorption on the basal planes because the F-SS and FF interactions are far stronger than the FB interaction. For adsorptives with lower polarity, exemplified by methanol or ammonia, the adsorption mechanism switches from clustering to layering in the order: ammonia, methanol; and we suggest that the bridging between these two mechanisms is a molecular spill-over phenomenon, which has not been previously proposed in the literature in the context of physical adsorption. PMID:25660710

Do, D D; Johnathan Tan, S L; Zeng, Yonghong; Fan, Chunyan; Nguyen, Van T; Horikawa, Toshihide; Nicholson, D

2015-05-15

262

Wormhole initiation and propagation of emulsified acid in carbonate cores using computerized tomography  

Microsoft Academic Search

Emulsified acids are widely used for stimulating carbonate reservoirs. This study examines alternate ways to evaluate the performance of emulsified acids by using a non-destructive visual-based technique. Using advanced image processing software and techniques, it was possible to examine the dissolution patterns created by emulsified acids at different operating conditions. Computerized Tomography (CT) was successful in monitoring wormhole initiation and

Shameem Siddiqui; Hisham A. Nasr-El-Din; Aon A. Khamees

2006-01-01

263

Kinetics of esterification of aromatic carboxylic acids over zeolites H? and HZSM5 using dimethyl carbonate  

Microsoft Academic Search

Esterification of benzoic acid and substituted benzoic acids has been carried out efficiently over zeolite H? and HZSM5 in an autoclave using dimethyl carbonate (DMC) as the methylating agent. The wide applicability of this esterification method to esterify a wide range of aromatic carboxylic acids has been demonstrated. This method is a viable and safe alternative to other esterification processes,

Sharath R. Kirumakki; N. Nagaraju; Komandur V. R. Chary; Sankarasubbier Narayanan

2003-01-01

264

Hydrothermal carbonization of microalgae II. Fatty acid, char, and algal nutrient products  

Microsoft Academic Search

A process for isolation of three products (fatty acids, chars and nutrient-rich aqueous phases) from the hydrothermal carbonization of microalgae is described. Fatty acid products derived from hydrolysis of fatty acid ester groups in the microalgae were obtained in high yield and were found to be principally adsorbed onto the char also created in the process. With the highest lipid-containing

Steven M. Heilmann; Lindsey R. Jader; Laurie A. Harned; Michael J. Sadowsky; Frederick J. Schendel; Paul A. Lefebvre; Marc G. von Keitz; Kenneth J. Valentas

2011-01-01

265

Activated carbon fibers from Nomex by chemical activation with phosphoric acid  

Microsoft Academic Search

The preparation of activated carbon fibers (ACFs) by phosphoric acid activation of Nomex [poly(m-phenylene isophthalamide)] polyaramid fibers was studied. Nomex pyrolysis in the presence of phosphoric acid was followed by thermogravimetry and infrared spectroscopy in order to establish the nature of transformations involved. Then, ACFs were obtained by impregnating Nomex with different amounts of phosphoric acid, followed by pyrolysis and

Fabián Suárez-Garc??a; Amelia Mart??nez-Alonso; Juan M. D Tascón

2004-01-01

266

Toxicity of pyrolysis gases from polypropylene  

NASA Technical Reports Server (NTRS)

A sample of polypropylene was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. The gases from this sample appeared to be equivalent or less toxic than the gases from a sample of polyethylene under these particular test conditions. Carbon monoxide appeared to be the principal toxicant.

Hilado, C. J.; Schneider, J. E.; Brauer, D. F.

1979-01-01

267

Electron microscopy of carbonaceous matter in Allende acid residues  

NASA Technical Reports Server (NTRS)

On the basis of characteristic diffuse ring diffraction patterns, much of the carbonaceous matter in a large suite of Allende acid residues has been identified as a variety of turbostratic carbon. Crystallites of this phase contain randomly stacked sp(2) hybridized carbon layers and diffraction patterns resemble those from carbon black and glassy carbon. Carbynes are probably absent, and are certainly restricted to less than 0.5% of these acid residues. The work of Ott et al. (1981) provides a basis for the possibility that turbostratic carbon is a carrier of noble gases, but an additional component - amorphous carbon - may be necessary to explain the high release temperatures of noble gases as well as the glassy character of many of the carbonaceous particles. Carbynes are considered to be questionable as important carriers of noble gases in the Allende acid residues.

Lumpkin, G. R.

1982-01-01

268

Thermodynamic limitations in organic acid-carbonate systems  

Microsoft Academic Search

Dow Chemical Co. and the University of Texas at Austin developed a correlation that permits the amount of unreacted organic acid (used in a well stimulation) to be calculated as a function of both temperature and initial acid strength. Organic acids are often used for the matrix acidization and the acid fracturing of carbonaceous formations because the rates of reaction

J. C. Chatelain; I. H. Silberberg; R. S. Schechter

1975-01-01

269

The Formation and Stability of Carbonic Acid on Outer Solar System Bodies  

NASA Technical Reports Server (NTRS)

The radiation chemistry, thermal stability, and vapor pressure of solid-phase carbonic acid (H2CO3) have been studied with mid-infrared spectroscopy. A new procedure for measuring this molecule's radiation stability has been used to obtain intrinsic IR band strengths and half-lives for radiolytic destruction. Results are compared to literature values. We report, for the first time, measurements of carbonic acid's vapor pressure and its heat of sublimation. We also report the first observation of a chemical reaction involving solid-phase carbonic acid. Possible applications of these findings are discussed, with an emphasis on the outer Solar System.

Peeters, Z.; Hudson, R. L.; Moore, M. H.; Lewis, Ariel

2009-01-01

270

16 Rangelands educing concentrations of greenhouse gases  

E-print Network

sequestration or decrease carbon loss will be especially important. The Terrestrial Carbon Cycle Prior the current amount of carbon being stored in an area. In the terrestrial carbon cycle (Supplemental Material and the atmosphere. Carbon dioxide (CO2 ) is one of the primary anthropogenic greenhouse gases. Reductions

271

Teacher's Resource Book for Balloons and Gases. Grade 6. Revised. Anchorage School District Elementary Science Program.  

ERIC Educational Resources Information Center

This resource book introduces sixth-grade children to the physical and chemical properties of gases. The unit begins with an investigation of acids and bases. Students then generate carbon dioxide, oxygen, and hydrogen, and investigate the properties of each. The unit culminates with an activity involving an unknown gas. Students conduct tests to…

Anchorage School District, AK.

272

Effect of Acid Oxidation on the Dispersion Property of Multiwalled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

A means of dispersion of multiwalled carbon nanotube (MWCNT) via mixed acid (HNO3 and H2SO4) oxidation with different treatment durations was investigated through the solubility study of the treated carbon nanotubes in some common solvents. Fourier transformed infrared (FTIR) characterization of the reaction products revealed that the surface of MWCNTs was successfully functionalized with surface acidic groups. The acid-base titration demonstrated that the amount of surface acidic groups increased in parallel with the refluxing duration. The acid modified MWCNTs were found to be well dispersed in polar solvents, such as ethanol and water due to the presence of the hydrophilic acid functional groups on the surface of raw MWCNTs. Such chemical modification of carbon nanotube properties will pave the way towards the realistic applications in the nanotechnology world.

Goh, P. S.; Ismail, A. F.; Aziz, M.

2009-06-01

273

Carbon Dioxide Information Analysis Center and World Data Center - A for atmospheric trace gases. Fiscal year 1996, annual report  

SciTech Connect

Fiscal year 1996 was especially productive for the Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL). This report describes publications and statistical data from the CDIAC.

Cushman, R.M.; Boden, T.A.; Jones, S.B. [and others

1997-02-01

274

Sulfonated mesoporous silica-carbon composites and their use as solid acid catalysts  

NASA Astrophysics Data System (ADS)

The synthesis of highly functionalized porous silica-carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica-carbon composites contain ˜30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.sbnd SO3H, sbnd COOH and sbnd OH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica-carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15.

Valle-Vigón, Patricia; Sevilla, Marta; Fuertes, Antonio B.

2012-11-01

275

Measurement of fossil fuel carbon dioxide and other anthropogenic trace gases from MEGAPOLI intensive campaign in Paris during winter 2010.  

NASA Astrophysics Data System (ADS)

The Paris agglomeration is the third biggest megacity in Europe (12 million inhabitants) and according to national emission inventories, is responsible for 15 % of the French anthropogenic CO2 emissions mainly originating from road transport, and residential and industrial energy consumption. The objective of our feasibility study was to design an efficient monitoring strategy in order to quantify future trends in anthropogenic CO2 emission in Paris area. During the winter campaign of the European project MEGAPOLI and the French project CO2-MEGAPARIS, we performed measurements of CO2 and related trace gases from January to February 2010. The RAMCES (Atmospheric Network for Greenhouse Gases Monitoring) team at LSCE monitored CO2 and CO mixing ratio with high temporal resolution using instruments based on Cavity Ring Down Spectroscopy (CRDS) in the thirteenth arrondissement of Paris (south). We also sampled air in more than fifty flasks covering three full days at the same place. Flask were analysed in the RAMCES central laboratory with a Gas Chromatograph system for CO2, CO, CH4, N2O, SF6 and H2 mixing ratios and also by Mass Spectroscopy for CO2 isotopic ratios (?13C and ?18O). In order to quantify the fossil fuel CO2 (CO2ff) most flasks were analysed at INSTAAR for ?14C in CO2. In addition, 13CO2 isotopic ratio and total CO2 concentration were measured at high temporal resolution (< 1 min) over three days at Paris with the SIMCO instrument developed at LPMAA. In parallel with the Paris measurements, in-situ CO2, CO and other trace gases were monitored at Gif-sur-Yvette, a semi urban station 20km south west of Paris and also at the Trainou tower, 100 km south of Paris. Similar synoptic variations of CO2and CO mixing ratios were found in Paris and Gif with maximum mixing ratio up to 495 ppm CO2 and 1000 ppb CO downtown Paris. The mean diurnal variation during this winter period shows a peak to peak amplitude of 15 ppm CO2 and 150 ppb CO at Paris and 10 ppm CO2 and 40 CO ppb at Gif station. Using the MEGAPOLI database we will test different tracers (CO, VOCs, NOx) as possible candidate to quantify CO2ff (fossil fuel) based on calibration of these tracers against CO2ff estimates based on D14C. These results from the campaign will be compared to the emission inventories from EDGAR 4.2 (global inventories) and the national ones from CITEPA and AirParif.

Lopez, M.; Schmidt, M.; Delmotte, M.; Gros, V.; Mondelain, D.; Lehman, S. J.; Ramonet, M.; Vuillemin, C.; Xueref-Remy, I.

2012-04-01

276

Measurement of fossil fuel carbon dioxide and other anthropogenic trace gases from MEGAPOLI intensive campaign in Paris during winter 2010  

NASA Astrophysics Data System (ADS)

The Paris agglomeration is the third biggest megacity in Europe (12 million inhabitants) and according to national emission inventories, is responsible for 15 % of the French anthropogenic CO2 emissions mainly originating from road transport, residential and industrial energy consumption. The objective of our feasibility study was to design an efficient monitoring strategy in order to quantify future trends in anthropogenic CO2 emission in Paris area. During the winter campaign of the European project MEGAPOLI and French project CO2-MEGAPARIS, we performed measurements of CO2 and related trace gases from January to February 2010. The RAMCES (Atmospheric Network for Greenhouse Gases Monitoring) team at LSCE monitored CO2 and CO mixing ratio with high temporal resolution using instruments based on Cavity Ring Down Spectroscopy (CRDS) in the thirteenth arrondissement of Paris (south). We also sampled air in more than fifty flasks covering three full days at the same place. Flasks were analysed in the RAMCES central laboratory with a Gas Chromatograph system for CO2, CO, CH4, N2O, SF6 and H2 mixing ratios and also by Mass Spectroscopy for CO2 isotopic ratios (?13C and ?18O). In order to quantify the fossil fuel CO2 (CO2ff) most flasks were analysed at INSTAAR for ?14C in CO2. In addition, 13CO2 isotopic ratio and total CO2 concentration were measured at high temporal resolution (< 1 min) over three days at Paris with Tunable Diode Laser Spectroscope developed at LPMAA. In parallel with the Paris measurements, in-situ CO2, CO and other trace gases were monitored at Gif-sur-Yvette, a semi urban station 20km south west of Paris. Similar synoptic variations of CO2 and CO mixing ratios were found in Paris and Gif with maximum mixing ratio up to 495 ppm CO2 and 1000 ppb CO downtown Paris. The mean diurnal variation during this winter period shows peak to peak amplitude of 15 ppm CO2 and 150 ppb CO at Paris and 10 ppm CO2 and 40 CO ppb at Gif station. We focused on CO and NOx as tracer of fossil fuel emission to estimate CO2ff. We calibrated these tracers against CO2ff estimates based on ?14C. Moreover, ?13C measurements were used to quantify the contribution of the different combustion sources for CO2 emission. Finally, we compared our results to the emission inventories from EDGAR 4.2 (global inventories), IER (European inventory) and the national ones from CITEPA and AirParif.

Lopez, M.; Schmidt, M.; Delmotte, M.; Gros, V.; Mondelain, D.; Lehman, S.; Ramonet, M.; Vuillemin, C.; Xueref-remy, I. C.

2012-12-01

277

Stability of carbon nanowalls against chemical attack with acid solutions  

NASA Astrophysics Data System (ADS)

In this paper we report on the stability of CNW layers, synthesized by a radiofrequency plasma jet, against the chemical attack with different acid solutions (sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid). We present the changes of the morphology and structure of the CNW caused by the post-growth chemical treatments. We demonstrate that self-sustaining and transferable CNW layers can be obtained, by chemically dissolving the substrates, while the initial characteristics of the material are well preserved.

Vizireanu, Sorin; Dinescu, Gheorghe; Nistor, Leona Cristina; Baibarac, Mihaela; Ruxanda, Grigore; Stancu, Mihaela; Ciuparu, Dragos

2013-01-01

278

Pyrolytic carbon membranes containing silica derived from poly(imide siloxane): the effect of siloxane chain length on gas transport behavior and a study on the separation of mixed gases  

Microsoft Academic Search

Poly(imide siloxane) (PIS) precursors have been synthesized in different compositions and appraised in their ability to form carbon membranes containing silica (C–SiO2). During inert pyrolysis, the imide domains in the PIS were transformed into a carbon-rich phase conferring a molecular sieving capability for molecular pairs of small gases, such as H2\\/N2, He\\/N2, CO2\\/N2, and O2\\/N2. The siloxane domains in the

Ho Bum Park; Chul Ho Jung; Youn Kook Kim; Sang Yong Nam; Sun Yong Lee; Young Moo Lee

2004-01-01

279

Molten Carbonate and Phosphoric Acid Stationary Fuel Cells: Overview and Gap Analysis  

SciTech Connect

This report describes the technical and cost gap analysis performed to identify pathways for reducing the costs of molten carbonate fuel cell (MCFC) and phosphoric acid fuel cell (PAFC) stationary fuel cell power plants.

Remick, R.; Wheeler, D.

2010-09-01

280

A model for matrix acidizing of long horizontal well in carbonate reservoirs  

E-print Network

of horizontal wells is attributed to various factors such as drilling induced formation damage, high completion skins, and variable formation properties along the length of the wellbore as in the case of heterogeneous carbonate reservoirs. Matrix acidizing...

Mishra, Varun

2009-06-02

281

Fabrication of carbon-aerogel electrodes for use in phosphoric acid fuel cells  

E-print Network

An experiment was done to determine the ability to fabricate carbon aerogel electrodes for use in a phosphoric acid fuel cell (PAFC). It was found that the use of a 25% solution of the surfactant Cetyltrimethylammonium ...

Tharp, Ronald S

2005-01-01

282

Surfactant Screening to Alter the Wettability and Aid in Acidizing Carbonate Formations  

E-print Network

Surfactant flooding in carbonate matrix acidizing treatment has been widely used for changing the wettability of the rock and to achieve low IFT values. Optimizing the type of surfactant and concentration for the specific oil field is very important...

Yadhalli Shivaprasad, Arun Kumar

2013-02-26

283

A tabulation of meterorological variables and concentrations of helium, carbon dioxide, oxygen, and nitrogen in soil gases collected regularly from four sites at the Roosevelt Hot Springs Known Geothermal Resources Area, Utah  

Microsoft Academic Search

A U.S. Geological Survey report is presented giving a tabulation of meterorological variables and concentrations of helium, carbon dioxide, oxygen, and nitrogen in soil gases collected regularly from four sites at the Roosevelt Hot Springs Known Geothermal Resources Area, Utah.

Hinkle

1989-01-01

284

Atmospheric gases  

NSDL National Science Digital Library

Which gases make up the atmosphere? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to the gaseous components of the atmosphere. Students explore the main gases of the atmosphere using a pop-up pie chart. Descriptions of the gases and their percentages in the atmosphere are provided. Students read about water vapor in the atmosphere, and an animation shows a simplified process of precipitation. A pop-up window explains the effects of dust on the atmosphere, and a photograph shows how large amounts of dust in the atmosphere create the reds and oranges displayed in sunsets. Finally, ozone is introduced to students as a necessary component of human life on Earth. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

285

Acid resistance contributes to the high-pressure carbon dioxide resistance of Escherichia coli K-12.  

PubMed

Effect of deletion of acid resistant genes of E. coli on the high-pressure carbon dioxide (HPC) resistance was investigated. Genes coding amino acid decarboxylases, such as lysine, arginine, and glutamate decarboxylase, were found to contribute to HPC resistance. Protonophore-treated cells showed hypersensitivity to HPC, confirming that HPC induced cytoplasm acidification and exerted severe damage on cells by intrusion of gaseous carbon dioxide into cytoplasm. PMID:25119308

Furukawa, Soichi; Shimazaki, Junji; Kawaharada, Kazumichi; Matsuda, Tsukasa; Aoyagi, Hiroki; Wakabayashi, Hidekazu; Ogihara, Hirokazu; Yamasaki, Makari; Morinaga, Yasushi

2015-01-01

286

Catalytic synthesis of benzoic esters with carbon-based solid acid from coal tar  

Microsoft Academic Search

A new carbon-based solid acid catalyst (C- SO3H) was prepared by simultaneous cross- linking coal tar with benzaldehyde,hoist temperature -curing ,sulphonation in sulfuric acid and was characterized by FT-IR,TG-DTG,XRD and neutralization potentiometric titration, and SEM techniques. The results indicated that there is the high density of SO3H groups in forming amorphous coke consisting of polycyclic aromatic carbon sheets, and the

Haie Hao; Baojun Ma; Jinxin Ma; Sun Yuan; Wanyi Liu

2011-01-01

287

The use of coiled tubing during matrix acidizing of carbonate reservoirs  

SciTech Connect

A laboratory and field study directed at improved well performance of horizontal wells is discussed. During the study, several wells were matrix acidized using bullhead and coiled tubing placement techniques. The study performed in carbonate reservoirs indicates acid placed with coiled tubing diverted with foam provides excellent zone coverage and damage removal. Conventional bullhead techniques do not result in effective damage removal. The study emphasizes the evaluation of the treatment results and the development of improved acidizing techniques. Laboratory simulations of matrix acidizing indicate proper placement techniques are essential. This observation is supported by field data in oil wells completed in carbonate reservoirs. The key to successful damage removal is (1) the placement of acid via coiled tubing and (2) proper diversion. Production logging and well performance data support this claim. The proposed treatment is applicable in both horizontal and vertical wells completed in carbonate reservoirs.

Thomas, R.L.; Milne, A.

1995-10-01

288

Isotopic composition of gases from mud volcanoes  

SciTech Connect

A study has been made of the isotopic composition of the carbon in methane and carbon dioxide, as well as hydrogen in the methane, in the gases of mud volcanoes, for all main mud volcano areas in the USSR. The isotopic composition of carbon and hydrogen in methane shows that the gases resemble those of oil and gas deposits, while carbon dioxide of these volcanoes has a heavier isotopic composition with a greater presence of ''ultraheavy'' carbon dioxide. By the chemical and isotopic composition of gases, Azerbaidzhan and South Sakhalin types of mud volcano gases have been identified, as well as Bulganak subtypes and Akhtala and Kobystan varieties. Correlations are seen between the isotopic composition of gases and the geological build of mud volcano areas.

Valysaev, B.M.; Erokhin, V.E.; Grinchenko, Y.I.; Prokhorov, V.S.; Titkov, G.A.

1985-09-01

289

Carbon dioxide and organic acids: origin and role in burial diagenesis (Texas Gulf Coast Tertiary)  

Microsoft Academic Search

Carbon dioxide produced by decarboxylation of organic matter is not a dominant factor in secondary porosity development. Material balance calculations indicate the amount of feldspar and carbonate dissolution that has taken place in Tertiary sandstones of the Texas Gulf Coast far exceeds that which is explainable by decarboxylation. Other potential sources of acid for dissolution reactions include reverse weathering reactions

Lundegard

1985-01-01

290

USE OF THE COMPOSITION AND STABLE CARBONIISOTOPE RATIO OF MICROBIAL FATTY ACIDS TO STUDY CARBON CYCLING  

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (*13C) of individual microbial phospholipid fatty acids (PLFAs) in soils and sediments as indicators of live microbial biomass levels and microbial carbon source. For studies of soil organic matter (SOM) cy...

291

Chemical modification of carbon fiber surfaces by nitric acid oxidation followed by reaction with tetraethylenepentamine  

Microsoft Academic Search

Amino groups react rapidly with both isocyanates and epoxides. Thus, to prepare carbon fibers which might exhibit enhanced adhesion to both polyurethanes and epoxy resin matrices, attempts were made to introduce a high surface amine concentration onto high-strength carbon fibers (derived from PAN) by nitric acid oxidation followed by reaction with excess tetraethylenepentamine (TEPA). Fibers were oxidized with concentrated (70%)

C. U. Pittman; G.-R. He; B. Wu; S. D. Gardner

1997-01-01

292

SIMULTANEOUS INHIBITION OF CARBON AND NITROGEN MINERALIZATION IN A FOREST SOIL BY SIMULATED ACID PRECIPITATION  

EPA Science Inventory

Acid Precipitation may alter the rates of microbial processes in soil that are important for forest productivity. Acidification of soil can result in a depression of carbon mineralization. The present study was designed to determine whether the inhibition of carbon mineralization...

293

Fiscal Year 1998 Annual Report, Carbon Dioxide Information Analysis Center, World Data Center -- A for Atmospheric Trace Gases  

SciTech Connect

Once again, the most recent fiscal year was a productive one for the Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL), as well as a year for change. The FY 1998 in Review section in this report summarizes quite a few new and updated data and information products, and the ''What's Coming in FY 1999'' section describes our plans for this new fiscal year. During FY 1998, CDIAC began a data-management system for AmeriFlux, a long-term study of carbon fluxes between the terrestrial biosphere of the Western Hemisphere and the atmosphere. The specific objectives of AmeriFlux are to establish an infrastructure for guiding, collecting, synthesizing, and disseminating long-term measurements of CO{sub 2}, water, and energy exchange from a variety of ecosystems; collect critical new information to help define the current global CO{sub 2} budget; enable improved predictions of future concentrations of atmospheric CO{sub 2}; and enhance understanding of carbon fluxes. Net Ecosystem Production (NEP), and carbon sequestration in the terrestrial biosphere. The data-management system, available from CDIAC'S AmeriFlux home page (http://cdiac.esd.ornl.gov/programs/ameriflux/ ) is intended to provide consistent, quality-assured, and documented data across all AmeriFlux sites in the US, Canada, Costa Rica, and Brazil. It is being developed by Antoinette Brenkert and Tom Boden, with assistance from Susan Holladay (who joined CDIAC specifically to support the AmeriFlux data-management effort).

Cushman, R.M.; Boden, T.A.; Hook, L.A.; Jones, S.B.; Kaiser, D.P.; Nelson, T.R.

1999-03-01

294

Integrated 3D Acid Fracturing Model for Carbonate Reservoir Stimulation  

E-print Network

in integrating fracture propagation, acid transport and dissolution, and well performance models in a seamless fashion for acid fracturing design. In this new approach, the fracture geometry data of a hydraulic fracture is first obtained from commercial models...

Wu, Xi

2014-06-23

295

Solid-State Carbon-13 Nuclear Magnetic Resonance of Humic Acids at High Magnetic Field Strengths  

E-print Network

commonplace in studies of humic substances in soils and sediments, but when modern high-field spectrometersSolid-State Carbon-13 Nuclear Magnetic Resonance of Humic Acids at High Magnetic Field Strengths were insignificant, and spectral interference due humic acids taken under a variety of conditions. We

Hemminga, Marcus A.

296

Polyvinylpyrrolidone and polyethylenimine as inhibitors for the corrosion of a low carbon steel in phosphoric acid  

Microsoft Academic Search

Polarization and weight loss studies showed that both polyvinylpyrrolidonc and polyethylenimine are effective for the inhibition of low carbon steel over a wide concentration range of aqueous phosphoric acid (H3PO4) solutions. Both polymers retard the anodic and cathodic corrosion reactions with emphasis on the former. The results for uninhibited acid confirm the kinetic expression proposed by Mathur and Vasudevan.

Y. Jianguo; W. Lin; V. Otieno-Alego; D. P. Schweinsberg

1995-01-01

297

Duboscic acid: a potent ?-glucosidase inhibitor with an unprecedented triterpenoidal carbon skeleton from Duboscia macrocarpa.  

PubMed

Duboscic acid (1), a triterpenoid with a unique carbon backbone, was isolated from Duboscia macrocarpa Bocq. It is the first member of a new class of triterpenoids, for which the name "dubosane" is proposed. Duboscic acid has a potent ?-glucosidase inhibition, and its structure was unambiguously deduced by a single-crystal X-ray diffraction study. PMID:21090700

Wafo, Pascal; Kamdem, Ramsay S T; Ali, Zulfiqar; Anjum, Shazia; Khan, Shamsun Nahar; Begum, Afshan; Krohn, Karsten; Abegaz, Berhanu M; Ngadjui, Bonaventure T; Choudhary, Muhammad Iqbal

2010-12-17

298

Carbon Isotope Compositions of Fatty Acids in Mussels from Newfoundland Estuaries  

NASA Astrophysics Data System (ADS)

This paper examines the carbon isotopic compositions of free fatty acids of two species of mussels (i.e. Mytilus edulis and Modiolus modiolus) from two estuarine environments around Newfoundland. Gas chromatography and conventional isotope ratio mass spectrometry were employed to characterize bulk fatty acids and gas chromatography/combustion/isotope ratio mass spectrometry was utilized to characterize the carbon isotope compositions of individual fatty acids. The bulk fatty acid distribution (dominance of 16:0, 20:5n3, 22:6n3 and 16:1) and carbon isotopic compositions (-27·3 to -25·8 per mil) indicate a dominant marine phytoplankton dietary source for the mussels. In contrast to the narrow range of bulk fatty acid ? 13C values, up to 7 per mil variation in ? 13C of individual fatty acids was observed. In general, saturated fatty acids are isotopically heavier than corresponding mono- and polyunsaturates, consistent with previously suggested kinetic isotope effect associated with de novo desaturation reactions. The depletion of 13 C in 18:4n3 compared with 22:6n3 and 20:5n3 indicates a distinct dietary source for 18:4n3. The present study shows the potential for detailed assessment of carbon flow in benthic ecosystems using fatty acids and other compound classes by gas chromatography/combustion/isotope ratio mass spectrometry.

Murphy, Dena E.; Abrajano, Teofilo A.

1994-09-01

299

PERFORMANCE AND MODELING OF A HOT POTASSIUM CARBONATE ACID GAS REMOVAL SYSTEM IN TREATING COAL GAS  

EPA Science Inventory

The report discusses the performance and modeling of a hot potassium carbonate (K2CO3) acid gas removal system (AGRS) in treating coal gas. Aqueous solutions of K2CO3, with and without amine additive, were used as the acid gas removal solvent in the Coal Gasification/Gas Cleaning...

300

Low-pressure adsorption of Ar, Kr, and Xe on carbonaceous materials (kerogen and carbon blacks), ferrihydrite, and montmorillonite: Implications for the trapping of noble gases onto meteoritic matter  

NASA Astrophysics Data System (ADS)

Noble gases trapped in meteorites are tightly bound in a carbonaceous carrier labeled "phase Q." Mechanisms having led to their retention in this phase or in its precursors are poorly understood. To test physical adsorption as a way of retaining noble gases into precursors of meteoritic materials, we have performed adsorption experiments for Ar, Kr, and Xe at low pressures (10 -4 mbar to 500 mbar) encompassing pressures proposed for the evolving solar nebula. Low-pressure adsorption isotherms were obtained for ferrihydrite and montmorillonite, both phases being present in Orgueil (CI), for terrestrial type III kerogen, the best chemical analog of phase Q studied so far, and for carbon blacks, which are present in phase Q and can be considered as possible precursors. Based on adsorption data obtained at low pressures relevant to the protosolar nebula, we propose that the amount of noble gases that can be adsorbed onto primitive materials is much higher than previously inferred from experiments carried out at higher pressures. The adsorption capacity increases from kerogen, carbon blacks, montmorillonite to ferrihydrite. Because of its low specific surface area, kerogen can hardly account for the noble gas inventory of Q. Carbon blacks in the temperature range 75 K-100 K can adsorb up to two orders of magnitude more noble gases than those found in Q. Irreversible trapping of a few percent of noble gases adsorbed on such materials could represent a viable process for incorporating noble gases in phase Q precursors. This temperature range cannot be ruled out for the zone of accretion of the meteorite precursors according to recent astrophysical models and observations, although it is near the lower end of the temperatures proposed for the evolving solar nebula.

Marrocchi, Yves; Razafitianamaharavo, Angelina; Michot, Laurent J.; Marty, Bernard

2005-05-01

301

Studies of the terrestrial O{sub 2} and carbon cycles in sand dune gases and in biosphere 2  

SciTech Connect

Molecular oxygen in the atmosphere is coupled tightly to the terrestrial carbon cycle by the processes of photosynthesis, respiration, and burning. This dissertation examines different aspects of this coupling in four chapters. Chapter 1 explores the feasibility of using air from sand dunes to reconstruct atmospheric O{sub 2} composition centuries ago. Such a record would reveal changes in the mass of the terrestrial biosphere, after correction for known fossil fuel combustion, and constrain the fate of anthropogenic CO{sub 2}.

Severinghaus, J.P.

1995-12-31

302

On the formation of carbonic acid (H2CO3) in solar system ices Weijun Zheng a,b  

E-print Network

On the formation of carbonic acid (H2CO3) in solar system ices Weijun Zheng a,b , Ralf I. Kaiser b) of the formation pro- cesses. Our experimental results indicate that carbonic acid might be present in the solar with energetic electrons in an ultrahigh vacuum chamber. Our laboratory studies confirm that ­ besides carbon

Kaiser, Ralf I.

303

Urinary homovanillic acid and vanillylmandelic acid in workers exposed to carbon disulfide.  

PubMed

Homovanillic acid (HVA) and vanillylmandelic acid (VMA), two end products of dopamine metabolism, were measured in 60 workers exposed to carbon disulfide (CS(2)) in a rayon factory and in 48 unexposed workers. The airborne CS(2) concentrations in eight major exposure zones of the plant were measured monthly over a period of 4 years, from 1990 to 1994. In addition, the exposure concentrations and exposure history of each worker were integrated to estimate the overall lifetime exposure. Industrial hygiene data showed that the geometric mean concentrations of CS(2) in the plant ranged from 2.68 to 20.19 ppm, and more than 15% of the studied population had been repeatedly exposed to CS(2) at concentrations exceeding the ACGIH recommended time-weighted average of 10 ppm. The results showed that there was a significantly lower level and a higher proportion of CS(2) workers with decreased HVA and VMA excretion. However, there were no statistical correlations between the two dopaminergic metabolites and the mean CS(2) concentration, and years of employment. In contrast, significant dose-effect relationships were observed between these two metabolites and the integrated cumulative exposure (ICE) variable. The correlation coefficients for ICE and HVA, and ICE and VMA were -0.35 (p < 0.01) and -0.20 (p <0.05), respectively. These data suggest that chronic exposure to CS(2) was associated with measurable reduction in catecholamine metabolite concentrations. This finding is compatible with the earlier observations in laboratory animals that CS(2) exposures interfere with neurochemical metabolism. PMID:8833779

Yang, X F; Lee, B L; New, A L; Ong, H Y; Ma, L; Zhang, Q; Ong, C N

1996-03-01

304

Stable carbon isotope ratios of fatty acids in seagrass and redhead ducks  

Microsoft Academic Search

Fatty acids were extracted from roots and rhizomes of the seagrass, Halodule wrightii, and from subcutaneous fat tissues of eight redhead ducks (Aythya americana) collected either in Texas or South Dakota. Stable carbon isotope ratios (?13C) of individual fatty acids were measured by gas chromatography\\/combustion\\/isotope ratio mass spectrometry (GC\\/C\\/IRMS). In cases where individual fatty acids were not completely resolved by

Beth Trust Hammer; Marilyn L. Fogel; Thomas C. Hoering

1998-01-01

305

Arsenopyrite mineral based electrochemical sensor for acid–base titrations in ? -butyrolactone and propylene carbonate  

Microsoft Academic Search

\\u000a Abstract  A novel acid–base sensor based on the natural mineral arsenopyrite for titrations in ?-butyrolactone and propylene carbonate is validated and studied. This sensor, which requires only small sample volumes, was\\u000a employed for the titrations of some important organic acids (benzoic, anthranilic, and salicylic acid) with potassium hydroxide.\\u000a A stable stationary potential was attained at the arsenopyrite electrode in ?-butyrolactone and

Zorka Stani?; Jelena Stepanovi?; Zoran Simi?

306

Roles of oleic acid during micropore dispersing preparation of nano-calcium carbonate particles  

Microsoft Academic Search

In the present work, nano-calcium carbonate powder was prepared by micropore dispersion method with assistance of oleic acid as surfactant. CO2 gas was dispersed into the Ca(OH)2\\/H2O slurry via a glass micropore-plate with the diameter of micropore about 20?m. To investigate the effect of oleic acid on the size of CaCO3 particles, different amount of oleic acid was added in

Jiuxin Jiang; Jie Liu; Chang Liu; Gaowen Zhang; Xinghou Gong; Jianing Liu

2011-01-01

307

Simplified Fixed Bed Design Models for the Adsorption of Acid Dyes on Novel Pine Cone Derived Activated Carbon  

Microsoft Academic Search

A novel activated carbon has been prepared by the activation of ground pine cones using phosphoric acid activation, and the\\u000a nitrogen Brunauer–Emmett–Teller surface area was 869 m2 g?1. Equilibrium isotherms were performed to assess the capacity of the activated carbon using two acidic dyes, namely Acid Blue\\u000a 113 and Acid Black 1. The monolayer equilibrium isotherm capacities of Acid Blue 113 and

Mahdi Hadi; Mohammad Reza Samarghandi; Gordon McKay

2011-01-01

308

X-ray microtomography of hydrochloric acid propagation in carbonate rocks.  

PubMed

Acid treatments are used in the oil and gas industry, to increase the permeability of the carbonate reservoirs by creating preferential channels, called wormholes. Channels formation is strongly influenced by acid type and injection rate. The aim of this study is to evaluate some characteristics of the microporous system of carbonate rocks, before and after acidizing. For that purpose X-ray high-resolution microtomography was used. The results show that this technique can be used as a reliable method to analyze microstructural characteristics of the wormholes. PMID:25485884

Machado, A C; Oliveira, T J L; Cruz, F B; Lopes, R T; Lima, I

2015-02-01

309

The Adsorption of Gold, Palladium, and Platinum from Acidic Chloride Solutions on Mesoporous Carbons  

SciTech Connect

Studies on the adsorption characteristics of gold, palladium, and platinum on mesoporous carbon (CMK-3) and sulfur-impregnated mesoporous carbon (CMK-3/S) evaluated the benefits/drawbacks of the presence of a layer of elemental sulfur inside mesoporous carbon structures. Adsorption isotherms collected for Au(III), Pd(II), and Pt(IV) on those materials suggest that sulfur does enhance the adsorption of those metal ions in mildly acidic environment (pH 3). The isotherms collected in 1 M HCl show that the benefit of sulfur disappears due to the competing influence of large concentration of chloride ions on the ion-exchanging mechanism of metal ions sorption on mesoporous carbon surfaces. The collected acid dependencies illustrate similar adsorption characteristics for CMK-3 and CMK-3/S in 1-5MHCl concentration range. Sorption of metal ions from diluted aqueous acidic mixtures of actual leached electronic waste demonstrated the feasibility of recovery of gold from such liquors.

Peter R. Zalupski; Rocklan McDowell

2014-10-01

310

Highly ordered three dimensional macroporous carbon spheres and their acid catalytic properties  

NASA Astrophysics Data System (ADS)

Highly ordered three dimensional macroporous carbon spheres bearing sulfonic acid groups (MPCS-SO3H) were prepared by incomplete carbonization of glucose in silica crystal bead template, followed by sulfonation and removal of the template. The composition and porous structure of the obtained carbon spheres were investigated by physical adsorption of nitrogen, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. The catalytic properties of the MPCS-SO3H were evaluated by esterification of ethanol with acetic acid, indicating that MPCS-SO3H possess remarkable catalytic performance (high stability and acid catalytic ability) for the esterification.

Huang, Hui; Zhang, Jianming; Zhang, Yuxiao; Lian, Suoyuan; Liu, Yang

2013-10-01

311

Porous structure and surface chemistry of phosphoric acid activated carbon from corncob  

NASA Astrophysics Data System (ADS)

Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (SBET = 2081 m2/g, Vtot = 1.1 cm3/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

Sych, N. V.; Trofymenko, S. I.; Poddubnaya, O. I.; Tsyba, M. M.; Sapsay, V. I.; Klymchuk, D. O.; Puziy, A. M.

2012-11-01

312

Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.  

PubMed

Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10?mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications. PMID:25371160

Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

2015-05-01

313

Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System  

PubMed Central

Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin. PMID:19582225

Fujioka, Kouki; Futamura, Yasuhiro; Shiohara, Tomoo; Hoshino, Akiyoshi; Kanaya, Fumihide; Manome, Yoshinobu; Yamamoto, Kenji

2009-01-01

314

Evaluation of different oxygen carriers for biomass tar reforming (II): Carbon deposition in experiments with methane and other gases  

Microsoft Academic Search

This work is a continuation of a previous paper by the authors [1] which analyzed the suitability of the Chemical Looping technology in biomass tar reforming. Four different oxygen carriers were tested with toluene as tar model compound: 60% NiO\\/MgAl2O4 (Ni60), 40% NiO\\/NiAl2O4 (Ni40), 40% Mn3O4\\/Mg–ZrO2 (Mn40) and FeTiO3 (Fe) and their tendency to carbon deposition was analyzed in the

Teresa Mendiara; Joakim M. Johansen; Rubén Utrilla; Anker D. Jensen; Peter Glarborg

2011-01-01

315

Fumaric acid: an overlooked form of fixed carbon in Arabidopsis and other plant species  

SciTech Connect

Photoassimilates are used by plants for production of energy, as carbon skeletons and in transport of fixed carbon between different plant organs. Many studies have been devoted to characterizing the factors that. regulate photoassimilate concentrations in different plant species. Most studies examining photoassimilate concentrations in C{sub 3} plants have focused on analyzing starch and soluble sugars. However, work presented here demonstrates that a number of C{sub 3} plants, including the popular model organism Arabidopsis thaliana (L.) Heynh., and agriculturally important plants, such as soybean [Glycine ma (L.) Merr.], contain significant quantities of furnaric acid. In fact, furnaric acid can accumulate to levels of several mg per g fresh weight in A-abidopsis leaves, often exceeding starch and soluble sugar levels. Furnaric acid is a component of the tricarboxylic acid cycle and, like starch and soluble sugars, can be metabolized to yield energy and carbon skeletons for production of other compounds. Fumaric acid concentrations increase with plant age and light intensity in Arabidopsis leaves. Arabidopsis phloem exudates contain significant quantities of fumaric acid, raising the possibility that fumaric acid may function in carbon transport.

Chia, D.W.; Yoder, T.J.; Reiter, W.D.; Gibson, S.I.

2000-10-01

316

Greenhouse Gases  

NSDL National Science Digital Library

This is a lesson where learners engage in a radiating heat activity and an activity that measures temperature in models with and without greenhouse gases. Learners will draw conclusions about the effect of greenhouse gases on temperature and on human life and kinesthetically model the absorbing and re-radiation of heat. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes, prerequisite concepts, common misconceptions, student journal and reading. This is lesson 3 in the Astro-Venture Atmospheric Science Training Unit. The purpose of the unit is to increase students’ awareness of and interest in astrobiology and the many career opportunities that utilize science, math and technology skills. The lessons are designed for educators to use in conjunction with the Astro-Venture multimedia modules.

317

Why strong acid pays off in carbonate reservoirs  

Microsoft Academic Search

The properties of hydrochloric acid in concentrations greater than 15% and how they can be used to increase formation conductivity, get greater penetration, and shorten well clean-up time are discussed. The factors affecting the fracturing efficiency of a high strength acid include reaction rates, spending time, effect of calcium chloride, fracture penetration, formation etching test, and inhibition. Graphs are included

O. E. Harris; C. W. Crowe; R. W. Dennis

1966-01-01

318

The Orbiting Carbon Observatory (OCO-2) Mission and Experience Gained from the Greenhouse gases Observing Satellite (GOSAT)  

NASA Astrophysics Data System (ADS)

The NASA Orbiting Carbon Observatory (OCO-2) will make space-based measurements of atmospheric CO2 with the precision, resolution, and coverage needed to characterize CO2 sources and sinks on regional scales and quantify their variability over the seasonal cycle. The OCO-2 mission will be a 'carbon copy' of the OCO mission, to minimize schedule and cost risks. The OCO-2 instrument has been built and is undergoing testing and characterization. OCO-2 will carry a single instrument that incorporates 3 high resolution grating spectrometers that will make bore-sighted measurements of reflected sunlight in near-infrared CO2 and molecular oxygen (O2) absorption bands. These measurements will be combined to provide spatially resolved estimates of the column-averaged CO2 dry air mole fraction, XCO2. The instrument collects 12 to 24 XCO2 soundings/second over the sunlit portion of the orbit, yielding 200 to 400 soundings per degree of latitude, or 0.5 to 1 million soundings every day. Thick clouds and aerosols will reduce the number of soundings available for XCO2 retrievals by 80-90%, but the remaining data is expected to yield XCO2 estimates with accuracies of ~0.3 to 0.5% (1 to 2 ppm) on regional scales every month. To verify the accuracy of the space-based XCO2 data, the OCO-2 validation program will use ground-based, solar-viewing Fourier Transform Spectrometers (FTS) in the Total Carbon Column Observing Network (TCCON) to tie the space-based XCO2 with the World Meteorological Organization (WMO) standard for atmospheric CO2, which is based on in situ observations of CO2 from flask measurements, tall towers, and aircraft. In preparation for the OCO-2 mission, we are using the OCO-2 algorithm to retrieve XCO2 from GOSAT measurements. We now retrieved XCO2 from GOSAT data from April 2009 to present. These retrievals are being validated with the TCCON network. This presentation will provide an overview of OCO-2 mission, including science objectives, instrument, algorithm, and validation plans as well as recent results from the GOSAT retrievals.

Eldering, A.; Gunson, M.; Crisp, D.; Miller, C. E.

2012-04-01

319

Production and characterization of methyl ester sophorolipids with 22-carbon-fatty acids.  

PubMed

In this study, various fatty acids of 18 and 22 carbons were used as substrates to produce sophorolipids in Candida bombicola ATCC 22214. Methyl esterification of erucic acid and C22-enriched rapeseed oil generated mainly acidic sophorolipids with different degrees of saturation in the fatty acid chain, which was demonstrated by structural analysis using HPLC, LC-MS and NMR spectroscopy. Regardless of methyl esterification, the rapeseed oil served as the best substrate for high production of sophorolipids among the tested. Methyl esterification also had no noticeable effect on the interfacial properties of sophorolipids. However, 22 carbons introduced in the fatty acid chain increased the hydrophobicity of sophorolipids, and therefore improved surface-active properties and biodegradability. PMID:20053555

Shin, Jae Dong; Lee, Jeongmi; Kim, Yong Bum; Han, In-Sun; Kim, Eun-Ki

2010-05-01

320

Chemical and biological consequences of using carbon dioxide versus acid additions in ocean acidification experiments  

USGS Publications Warehouse

Use of different approaches for manipulating seawater chemistry during ocean acidification experiments has confounded comparison of results from various experimental studies. Some of these discrepancies have been attributed to whether addition of acid (such as hydrochloric acid, HCl) or carbon dioxide (CO2) gas has been used to adjust carbonate system parameters. Experimental simulations of carbonate system parameter scenarios for the years 1766, 2007, and 2100 were performed using the carbonate speciation program CO2SYS to demonstrate the variation in seawater chemistry that can result from use of these approaches. Results showed that carbonate system parameters were 3 percent and 8 percent lower than target values in closed-system acid additions, and 1 percent and 5 percent higher in closed-system CO2 additions for the 2007 and 2100 simulations, respectively. Open-system simulations showed that carbonate system parameters can deviate by up to 52 percent to 70 percent from target values in both acid addition and CO2 addition experiments. Results from simulations for the year 2100 were applied to empirically derived equations that relate biogenic calcification to carbonate system parameters for calcifying marine organisms including coccolithophores, corals, and foraminifera. Calculated calcification rates for coccolithophores, corals, and foraminifera differed from rates at target conditions by 0.5 percent to 2.5 percent in closed-system CO2 gas additions, from 0.8 percent to 15 percent in the closed-system acid additions, from 4.8 percent to 94 percent in open-system acid additions, and from 7 percent to 142 percent in open-system CO2 additions.

Yates, Kimberly K.; DuFore, Christopher M.; Robbins, Lisa L.

2013-01-01

321

Assessing the potential of amino acid ?13C patterns as a carbon source tracer in marine sediments: effects of algal growth conditions and sedimentary diagenesis  

NASA Astrophysics Data System (ADS)

Burial of organic carbon in marine sediments has a profound influence in marine biogeochemical cycles, and provides a sink for greenhouse gases such as CO2 and CH4. However, tracing organic carbon from primary production sources as well as its transformations in the sediment record remains challenging. Here we examine a novel but growing tool for tracing biosynthetic origin of amino acid carbon skeletons, based on natural occurring stable carbon isotope patterns in individual amino acids (?13CAA). We focus on two important aspects for ?13CAA utility in sedimentary paleoarchives: first, the fidelity of source diagnostic of algal ?13CAA patterns across different oceanographic growth conditions; and second, the ability of ?13CAA patterns to record the degree of subsequent microbial amino acid synthesis after sedimentary burial. Using the marine diatom Thalassiosira weissflogii, we tested under controlled conditions how ?13CAA patterns respond to changing environmental conditions, including light, salinity, temperature, and pH. Our findings show that while differing oceanic growth conditions can change macromolecular cellular composition, ?13CAA isotopic patterns remain largely invariant. These results underscore that ?13CAA patterns should accurately record biosynthetic sources across widely disparate oceanographic conditions. We also explored how ?13CAA patterns change as a function of age, total nitrogen and organic carbon content after burial, in a marine sediment core from a coastal upwelling area off Peru. Based on the four most informative amino acids for distinguishing between diatom and bacterial sources (i.e. isoleucine, lysine, leucine and tyrosine), bacterial derived amino acids ranged from 10-15% in the sediment layers from the last 5000 years to 35% during the last glacial period. The larger bacterial fractions in older sediments indicate that bacterial activity and amino acid resynthesis progressed, approximately as a function of sediment age, to a substantially larger degree than suggested by changes in total organic nitrogen and carbon content. Taken together, these culturing and sediment studies suggest that ?13CAA patterns in sediments represent a novel proxy for understanding both primary production sources, as well as direct bacterial role in the ultimate preservation of sedimentary organic matter.

Larsen, T.; Bach, L. T.; Salvatteci, R.; Wang, Y. V.; Andersen, N.; Ventura, M.; McCarthy, M. D.

2015-01-01

322

Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice.  

PubMed

Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 microg of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 microg LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 microg of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 microg of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon nanotubes. Further experiments are needed to understand the physico-chemical processes involved in this phenomenon. PMID:19481103

Tong, Haiyan; McGee, John K; Saxena, Rajiv K; Kodavanti, Urmila P; Devlin, Robert B; Gilmour, M Ian

2009-09-15

323

Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice  

SciTech Connect

Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 {mu}g of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 {mu}g LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 {mu}g of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 {mu}g of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon nanotubes. Further experiments are needed to understand the physico-chemical processes involved in this phenomenon.

Tong Haiyan [Human Studies Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)], E-mail: tong.haiyan@epa.gov; McGee, John K. [Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Saxena, Rajiv K. [School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Kodavanti, Urmila P. [Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Devlin, Robert B. [Human Studies Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Gilmour, M. Ian [Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)

2009-09-15

324

A facile hydrothermal approach towards photoluminescent carbon dots from amino acids.  

PubMed

A facile one-pot method to fabricate photoluminescent carbon dots (CDs) was developed by the hydrothermal treatment of amino acids at mild temperatures. Derived from three different kinds of amino acids including serine, histidine, and cystine, the resultant CDs show uniform spherical morphology with the diameters in the range of ?2.5-4.7nm. These amino acid derived CDs also manifest excellent photoluminescence behavior with the quantum yields (QYs) of ?7.5% and high stability. More importantly, this method provides the opportunity to modify the sizes, structures, and photoluminescent behavior of CDs by the utilization of diversified amino acids with different structural characteristics. PMID:25463184

Pei, Supeng; Zhang, Jing; Gao, Mengping; Wu, Dongqing; Yang, Yuxing; Liu, Ruili

2015-02-01

325

Effects of moisture and burning on soil-atmosphere exchange of trace carbon gases in a southern African savanna  

NASA Astrophysics Data System (ADS)

Soil fluxes of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) were measured during a period of extreme drought at semi-arid savanna sites located in the Kruger National Park (KNP), South Africa, as part of the SAFARI-92 experiments (Sept., 1992). Soil respiration in this savanna was little affected by burning, but was strongly stimulated by addition of moisture. Mean soil respiration from the dry soil was 0.4 g C m-2 d-1 in open savanna plots that had been burned biennially and 0.5 g C m-2 d-1 in woody savanna plots. A light natural rain (about 0.6 mm) increased the CO2 flux in the open savanna sites by 5-fold but the effect was short-lived. A simulated heavy rain (25 mm of added distilled water) increased CO2 fluxes by over an order of magnitude in both burned and control sites and the emissions remained over 5 times pre-wetting values during a week of drying. Over 65% of our measurements indicated no significant soil-atmosphere methane exchange; most of the few non-zero measurements indicated a small (<1 mg CH4-C m-2 d-1) flux of methane to the atmosphere. Soil-atmosphere CH4 exchange was not significantly affected by either burning the grass layer or by the addition of distilled water to the soil. The net soil CO fluxes, which generally increased with increasing soil temperature, were positive up to 356 × 109 molecules cm-2 s-1 with an average of 8.8 × 1010 molecules cm-2 s-1 for the untreated open savanna plots. After burning, the fluxes rose by over an order of magnitude but dropped back to preburn levels within a few days. Observed CO fluxes were higher than those previously reported for southern Africa savannas during non-drought conditions. Added moisture had little effect on CO fluxes during the 3-week period of SAFARI-92.

Zepp, Richard G.; Miller, William L.; Burke, Roger A.; Parsons, Dirk A. B.; Scholes, Mary C.

1996-10-01

326

Carbon dioxide-sustained adsorption of lactic acid at pH > pK{sub a} of the acid  

SciTech Connect

Experimental data are presented for batch and fixed-bed adsorption of lactic acid from aqueous sodium lactate solutions onto the tertiary amine sorbents, Dowex MWA-1 and Amberlite IRA-35, in the presence of carbon dioxide. The effects of carbon dioxide pressure and sodium lactate concentration on lactate uptake capacity were measured. A simple complexation model, which includes chemical-equilibria and mass- and charge-balance equations, was developed to describe the system. There are no fitted parameters in the model. The model predictions compare well with batch adsorption data.

Husson, S.M.; King, C.J. [Lawrence Berkeley National Lab., CA (United States)] [Lawrence Berkeley National Lab., CA (United States)

1999-04-01

327

Pressure-Activated Microsyringe Composite Scaffold of Poly(L-lactic acid) and Carbon Nanotubes for Bone Tissue Engineering  

E-print Network

Pressure-Activated Microsyringe Composite Scaffold of Poly(L-lactic acid) and Carbon Nanotubes biocompatibility. In this study, we microfabricated three-dimensional (3D) scaffolds by mixing poly(L-lactic acid

Daraio, Chiara

328

[Preparation, characterization and adsorption performance of mesoporous activated carbon with acidic groups].  

PubMed

Mesoporous activated carbons containing acidic groups were prepared with cotton stalk based fiber as raw materials and H3PO4 as activating agent by one step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on the yield, elemental composition, oxygen-containing acid functional groups and adsorptive capacity of activated carbon were studied. The adsorption capacity of the prepared activated carbon AC-01 for p-nitroaniline and Pb(II) was studied, and the adsorption mechanism was also suggested according to the equilibrium experimental results. The maximum yield of activated carbons prepared from cotton stalk fiber reached 35.5% when the maximum mesoporous volume and BET surface area were 1.39 cm3 x g(-1) and 1 731 m2 x g(-1), respectively. The activated carbon AC-01 prepared under a H3 PO4/precursor ratio of 3:2 and activated at 900 degrees C for 90 min had a total pore volume of 1.02 cm3 x g(-1), a micoporous ratio of 31%, and a mesoporous ratio of 65%. The pore diameter of the mesoporous activated carbon was mainly distributed in the range of 2-5 nm. The Langmuir maximum adsorption capacities of Pb(II) and p-nitroaniline on cotton stalk fiber activated carbon were 123 mg x g(-1) and 427 mg x g(-1), respectively, which were both higher than those for commercial activated carbon fiber ACF-CK. The equilibrium adsorption experimental data showed that mesopore and oxygen-containing acid functional groups played an important role in the adsorption. PMID:23947073

Li, Kun-Quan; Li, Ye; Zheng, Zheng; Zhang, Yu-Xuan

2013-06-01

329

Grafting of Polyesters from Carbon Fiber. Anionic Ring-Opening Copolymerization of Epoxides with Cyclic Acid Anhydrides Initiated by COOK Groups on the Surface of Carbon Fiber  

Microsoft Academic Search

To modify the surface of carbon fiber, the anionic grafting of polyesters from potassium carboxylate (COOK) groups on the surface was investigated. The COOK groups were introduced onto the surface of carbon fiber by the reaction of carboxyl groups (introduced by the oxidation of the surface with nitric acid) with potassium hydroxide. Untreated carbon fiber has no ability to initiate

Norio Tsubokawa; Hiroshi Hamada; Yasuo Sone

1989-01-01

330

Use of molecular modeling to determine the interaction and competition of gases within coal for carbon dioxide sequestration  

SciTech Connect

Molecular modeling was employed to both visualize and probe our understanding of carbon dioxide sequestration within a bituminous coal. A large-scale (>20,000 atoms) 3D molecular representation of Pocahontas No. 3 coal was generated. This model was constructed based on a the review data of Stock and Muntean, oxidation and decarboxylation data for aromatic clustersize frequency of Stock and Obeng, and the combination of Laser Desorption Mass Spectrometry data with HRTEM, enabled the inclusion of a molecular weight distribution. The model contains 21,931 atoms, with a molecular mass of 174,873 amu, and an average molecular weight of 714 amu, with 201 structural components. The structure was evaluated based on several characteristics to ensure a reasonable constitution (chemical and physical representation). The helium density of Pocahontas No. 3 coal is 1.34 g/cm{sup 3} (dmmf) and the model was 1.27 g/cm{sup 3}. The structure is microporous, with a pore volume comprising 34% of the volume as expected for a coal of this rank. The representation was used to visualize CO{sub 2}, and CH{sub 4} capacity, and the role of moisture in swelling and CO{sub 2}, and CH{sub 4} capacity reduction. Inclusion of 0.68% moisture by mass (ash-free) enabled the model to swell by 1.2% (volume). Inclusion of CO{sub 2} enabled volumetric swelling of 4%.

Jeffrey D. Evanseck; Jeffry D. Madura; Jonathan P. Mathews

2006-04-21

331

Carbon isotope composition of low molecular weight hydrocarbons and monocarboxylic acids from Murchison meteorite  

NASA Technical Reports Server (NTRS)

Carbon isotopic compositions have been measured for individual hydrocarbons and monocarboxylic acids from the Murchison meteorite, a C2 carbonaceous chondrite which fell in Australia in 1969. With few exceptions, notably benzene, the volatile products are substantially isotopically heavier than their terrestrial counterparts, signifying their extraterrestrial origin. For both classes of compounds, the ratio of C-13 to C-12 decreases with increasing carbon number in a roughly parallel manner, and each carboxylic acid exhibits a higher isotopic ratio than the hydrocarbon containing the same number of carbon atoms. These trends are consistent with the kinetically controlled synthesis of higher homologues from lower ones. The results suggest the possibility that the production mechanisms for hydrocarbons and carboxylic acids may be similar, and impose constraints on the identity of the reactant species.

Yuen, G.; Blair, N.; Des Marais, D. J.; Chang, S.

1984-01-01

332

One-Pot synthesis of phosphorylated mesoporous carbon heterogeneous catalysts with tailored surface acidity  

SciTech Connect

Soft-templated phosphorylated mesoporous carbons with homogeneous distributions of phosphate groups were prepared by a 'one-pot' synthesis method using mixtures of phosphoric acid with hydrochloric, or nitric acids in the presence of Pluronic F127 triblock copolymer. Adjusting the various ratios of phosphoric acid used in these mixtures resulted in carbons with distinct adsorption, structural and surface acidity properties. The pore size distributions (PSDs) from nitrogen adsorption at -196 C showed that mesoporous carbons exhibit specific surface areas as high as 551 m{sup 2}/g and mesopores as large as 13 nm. Both structural ordering of the mesopores and the final phosphate contents were strongly dependent on the ratios of H{sub 3}PO{sub 4} in the synthesis gels, as shown by transmission electron microscopy (TEM), X-ray photoelectron (XPS) and energy dispersive X-ray spectroscopy (EDS). The number of surface acid sites determined from temperature programmed desorption of ammonia (NH{sub 3}-TPD) were in the range of 0.3-1.5 mmol/g while the active surface areas are estimated to comprise 5-54% of the total surface areas. Finally, the conversion temperatures for the isopropanol dehydration were lowered by as much as 100 C by transitioning from the least acidic to the most acidic catalysts surface.

Fulvio, Pasquale F [ORNL; Mahurin, Shannon Mark [ORNL; Mayes, Richard T [ORNL; Bauer, Christopher [ORNL; Wang, Xiqing [ORNL; Veith, Gabriel M [ORNL; Dai, Sheng [ORNL

2012-01-01

333

An Examination of the Carbon Isotope Effects Associated with Amino Acid Biosynthesis  

NASA Astrophysics Data System (ADS)

Stable carbon isotope ratios (?13C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, methylotrophic, methanogenic, acetogenic, acetotrophic, and naturally occurring cryptoendolithic communities from the Dry Valleys of Antarctica. Here we demonstrated that reactions involved in amino acid biosynthesis can be used to distinguish amino acids formed by life from those formed by nonbiological processes. The unique patterns of ?13C imprinted by life on amino acids produced a biological bias. We also showed that, by applying discriminant function analysis to the ?13C value of a pool of amino acids formed by biological activity, it was possible to identify key aspects of intermediary carbon metabolism in the microbial world. In fact, microorganisms examined in this study could be placed within one of three metabolic groups: (1) heterotrophs that grow by oxidizing compounds containing three or more carbon-to-carbon bonds (fermenters and organotrophs), (2) autotrophs that grow by taking up carbon dioxide (chemolitotrophs and phototrophs), and (3) acetoclastic microbes that grow by assimilation of formaldehyde or acetate (methylotrophs, methanogens, acetogens, and acetotrophs). Furthermore, we demonstrated that cryptoendolithic communities from Antarctica grouped most closely with the autotrophs, which indicates that the dominant metabolic pathways in these communities are likely those utilized for CO2 fixation. We propose that this technique can be used to determine the dominant metabolic types in a community and reveal the overall flow of carbon in a complex ecosystem.

Scott, James H.; O'Brien, Diane M.; Emerson, David; Sun, Henry; McDonald, Gene D.; Salgado, Antonio; Fogel, Marilyn L.

2006-12-01

334

An examination of the carbon isotope effects associated with amino acid biosynthesis.  

PubMed

Stable carbon isotope ratios (delta(13)C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, methylotrophic, methanogenic, acetogenic, acetotrophic, and naturally occurring cryptoendolithic communities from the Dry Valleys of Antarctica. Here we demonstrated that reactions involved in amino acid biosynthesis can be used to distinguish amino acids formed by life from those formed by nonbiological processes. The unique patterns of delta(13)C imprinted by life on amino acids produced a biological bias. We also showed that, by applying discriminant function analysis to the delta(13)C value of a pool of amino acids formed by biological activity, it was possible to identify key aspects of intermediary carbon metabolism in the microbial world. In fact, microorganisms examined in this study could be placed within one of three metabolic groups: (1) heterotrophs that grow by oxidizing compounds containing three or more carbon-to-carbon bonds (fermenters and organotrophs), (2) autotrophs that grow by taking up carbon dioxide (chemolitotrophs and phototrophs), and (3) acetoclastic microbes that grow by assimilation of formaldehyde or acetate (methylotrophs, methanogens, acetogens, and acetotrophs). Furthermore, we demonstrated that cryptoendolithic communities from Antarctica grouped most closely with the autotrophs, which indicates that the dominant metabolic pathways in these communities are likely those utilized for CO(2 )fixation. We propose that this technique can be used to determine the dominant metabolic types in a community and reveal the overall flow of carbon in a complex ecosystem. PMID:17155886

Scott, James H; O'Brien, Diane M; Emerson, David; Sun, Henry; McDonald, Gene D; Salgado, Antonio; Fogel, Marilyn L

2006-12-01

335

USE OF MOLECULAR MODELING TO DETERMINE THE INTERACTION AND COMPETITION OF GASES WITHIN COAL FOR CARBON DIOXIDE SEQUESTRATION  

SciTech Connect

We have made progress in carrying out large scale molecular dynamics simulations using the CHARMM force field in order to refine our coal/guest interactions. There have been two issues facing us over the last year. First, we have had to create a completely new topology and parameter definition for coal. Since we are using a classical force field, we have adopted the strategy of treating coal composed of individual common fragments based upon a distribution of mass, composition, and bonding. Our procedure is similar to treating a protein as being composed of the discrete set of amino acids. Second, we have had to incorporate the quality CO{sub 2} parameters that we have developed over the last two years. There are the geometric and arithmetic procedures, which we have successfully implemented. We have utilized computational molecular modeling to generate a state-of-the-art large scale structural representation of a bituminous coal of low volatile bituminous rank. This structure(s) has been used to investigate the molecular forces between the bituminous coal structure (or idealized pores) and the molecular species CH{sub 4} and CO{sub 2}. We are close to carrying out molecular dynamics simulations, which will allow us to explore and test the newly created model of coal.

Jeffrey D. Evanseck; Jeffry D. Madura; Jonathan P. Mathews

2005-05-27

336

Degradation of poly(ethylene- co-methacrylic acid)–calcium carbonate nanocomposites  

Microsoft Academic Search

Composites of poly(ethylene-co-methacrylic acid) with 5 mass fraction percent of precipitated calcium carbonate nanoparticles were prepared by melt extrusion on a miniature melt-blender and medium-scale production equipment. The composites consisted mostly of isolated particles. The ultimate mechanical properties of the nanocomposites were consequently largely superior to composites with micron-sized filler. The calcium carbonate particles were shown to offer a large

R. H. Krämer; M. A. Raza; U. W. Gedde

2007-01-01

337

Interaction of organic compounds with calcium carbonate--III. Amino acid composition of sorbed layers  

Microsoft Academic Search

Nitrogenous organic compounds in sorbed surface layers and in calcified organic matter associated with calcium carbonate sediment particles consist of 40-50% amino acids, 2% amino sugars and 25% ammonia. In grain size classes > 20 m these compounds are mainly contained in the calcified protein of carbonate secreting organisms but with smaller grain sizes--and consequently increased specific surface area--they are

Peter J. Müller; Erwin Suess

1977-01-01

338

Wine wastes as carbon source for biological treatment of acid mine drainage  

Microsoft Academic Search

Possible use of wine wastes containing ethanol as carbon and energy source for sulphate-reducing bacteria (SRB) growth and activity in the treatment of acid mine drainage (AMD) is studied for the first time. The experiments were performed using anaerobic down-flow packed bed reactors in semi-continuous systems. The performance of two bioreactors fed with wine wastes or ethanol as carbon sources

M. C. Costa; E. S. Santos; R. J. Barros; C. Pires; M. Martins

2009-01-01

339

Utilization of carbon and nitrogen sources and acid\\/alkali production by cowpea rhizobia  

Microsoft Academic Search

Summary Sixteen slow-growing strains of rhizobia (15 cowpea rhizobia and oneR. japonicum) were examined to determine the effects of carbon and nitrogen sources on acid\\/alkali production in culture media. We found that the pH changes of the medium were more influenced by nitrogen sources than carbon sources (with the exception of ribose). When ammonium sulphate was used as a nitrogen

M. H. Ahmad; Eustace Smith

1985-01-01

340

Covalent functionalization of single walled carbon nanotubes with peptide nucleic acid: Nanocomponents for molecular level electronics  

Microsoft Academic Search

Imparting molecular recognition to carbon nanotubes (CNTs) by conjugating them with bio-molecules has been an area of great interest as the resulting highly functionalized CNT-bioconjugates find their applications in various fields like molecular level electronics, pharmaceuticals, drug delivery, novel materials and many others. In this work we demonstrate the synthesis of functionally engineered single walled carbon nanotubes (SWNTs)-peptide nucleic acid

Krishna V. Singh; Rajeev R. Pandey; Xu Wang; Roger Lake; Cengiz S. Ozkan; Kang Wang; Mihrimah Ozkan

2006-01-01

341

Electroplated reticulated vitreous carbon current collectors for lead–acid batteries: opportunities and challenges  

Microsoft Academic Search

Reticulated, open-cell structures based on vitreous carbon substrates electroplated with a Pb–Sn (1wt.%) alloy were investigated as current collectors for lead–acid batteries. Scanning and backscattered electron microscopy, cyclic voltammetry, anodic polarization and flooded 2V single-cell battery testing was employed to characterize the performance of the proposed collectors. A battery equipped with pasted electroplated reticulated vitreous carbon (RVC) electrodes of 137cm2

Elod Gyenge; Joey Jung; Basanta Mahato

2003-01-01

342

Solubilities of benzoin, propyl 4-hydroxybenzoate and mandelic acid in supercritical carbon dioxide  

Microsoft Academic Search

A semi-flow type apparatus was used to measure the equilibrium solubilities of benzoin , propyl 4-hydroxybenzoate, and mandelic acid in supercritical carbon dioxide at 308.15, 318.15, and 328.15K over the pressure range from 9 to 24MPa. New equilibrium data of solid solubility in supercritical carbon dioxide are presented. The approach to solid–fluid phase equilibrium is examined based on a plug

Kong-Wei Cheng; Muoi Tang; Yan-Ping Chen

2002-01-01

343

Kinetics of dodecanoic acid adsorption from caustic solution by activated carbon  

Microsoft Academic Search

This study examines the influences of adsorbent porosity and surface chemistry and of carbon dosage on dodecanoic acid adsorption kinetics from aqueous and 2 M NaOH solutions as batch adsorption processes. Both adsorbents are steam-activated carbons prepared from either coconut or coal precursors. Prior to use the adsorbents were washed in deionized water or 2 M NaOH. Mass transfer coefficients and effective

Phillip Pendleton; Sophie Hua Wu

2003-01-01

344

Catalytic ozonation of p-chlorobenzoic acid by activated carbon and nickel supported activated carbon prepared from petroleum coke.  

PubMed

The aim of this research was to investigate catalytic activity of petroleum coke, activated carbon (AC) prepared from this material, Ni supported catalyst on activated carbon (Ni/AC) in the ozonation of aqueous phase p-chlorobenzoic acid (p-CBA). Activated carbon and Ni/AC catalyst were characterized by XRD and SEM. The presence of petroleum coke did not improve the degradation of p-CBA compared to ozonation alone, but it was advantageous for p-CBA mineralization (total organic carbon, TOC, reduction), indicating the generation of highly oxidant species (*OH) in the medium. The presence of either activated carbon or Ni/AC considerably improves TOC removal during p-CBA ozonation. Ni/AC catalyst shows the better catalytic activity and stability based on five repeated tests during p-CBA ozonation. During the ozonation (50 mg/h ozone flow rate) of a 10 mg/L p-CBA (pH 4.31), it can be more mineralized in the presence of Ni/AC catalyst (5.0 g/L), TOC removal rate is over 60% in 60 min, 43% using activated carbon as catalyst, only 30% with ozonation alone. PMID:18667273

Li, Xukai; Zhang, Qiuyun; Tang, Lili; Lu, Ping; Sun, Fengqiang; Li, Laisheng

2009-04-15

345

REMOVAL OF MOLYBDENUM FROM ACID LEACH LIQUORS BY ACTIVATED CARBON  

Microsoft Academic Search

Data are presented on the absorption of molybdenum on activated carbon. ;\\u000a The effect of retention time and linear flow on absorption, the use of sodium ;\\u000a hydroxide as an eluant, and the possibility of recovering molybdenum from the ;\\u000a caustic eluate are discussed. (auth)

E. T. Hollis; H. E. Dixon

1958-01-01

346

Recovery of calcium carbonate from steelmaking slag and utilization for acid mine drainage pre-treatment.  

PubMed

The conversion of steelmaking slag (a waste product of the steelmaking process) to calcium carbonate (CaCO(3)) was tested using hydrochloric acid, ammonium hydroxide and carbon dioxide via a pH-swing process. Batch reactors were used to assess the technical feasibility of calcium carbonate recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effects of key process parameters, such as the amount of acid (HCl/calcium molar ratio), the pH and the CO(2) flow rate were considered. It was observed that calcium extraction from steelmaking slag significantly increased with an increase in the amount of hydrochloric acid. The CO(2) flow rate also had a positive effect on the carbonation reaction rate but did not affect the morphology of the calcium carbonate produced for values less than 2 L/min. The CaCO(3) recovered from the bench scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with the commercial laboratory grade CaCO(3). PMID:22643421

Mulopo, J; Mashego, M; Zvimba, J N

2012-01-01

347

The electrochemical reduction of carbon dioxide to formate/formic acid: engineering and economic feasibility.  

PubMed

The engineering and economic feasibility of large-scale electrochemical reduction of carbon dioxide to formate salts and formic acid is the focus of this Full Paper. In our study we investigated the long-term performance of tin and other proprietary catalysts in the reduction of carbon dioxide to formate/formic acid at a gas/solid/liquid interface, using a flow-through reactor. The overall economics and energy consumption of the process are evaluated through a value chain analysis. The sensitivity of the net present value of the process to various process parameters is examined. PMID:21922681

Agarwal, Arun S; Zhai, Yumei; Hill, Davion; Sridhar, Narasi

2011-09-19

348

Simultaneous determination of levodopa, NADH, and tryptophan using carbon paste electrode modified with carbon nanotubes and ferrocenedicarboxylic acid  

Microsoft Academic Search

The redox response of a modified carbon nanotube paste electrode of ferrocenedicarboxylic acid was investigated. Cyclic voltammetry,\\u000a differential pulse voltammetry, and chronoamperometry were used to investigate the electrochemical behavior of levodopa (LD)\\u000a at modified electrode. Under the optimized conditions (pH 5.0), the modified electrode showed high electrocatalytic activity\\u000a toward LD oxidation; the overpotential for the oxidation of LD was decreased

Mohammad Reza Akhgar; Mohammad Salari; Hassan Zamani

2011-01-01

349

Corrosion effects of hydrogen sulfide on coiled tubing and carbon steel in hydrochloric acid  

SciTech Connect

Coiled tubing is commonly used in oilwell drilling and stimulation. It has been reported to be less susceptible to acid attack than carbon steel in acidizing. Corrosion problems are frequently reported from field activities and include corrosion/erosion, galvanic attack, brine/oxygen/acid attack, and HCl/H{sub 2}S attack. In this study, coiled tubing was exposed to inhibited HCl acid in the presence and absence of H{sub 2}S. Four HCl inhibitors and one H{sub 2}S inhibitor were evaluated, and the corrosion rates of coiled tubing, carbon steel (J-55), and carburized steel were compared. Tests were conducted at atmospheric pressure for temperatures less than and equal to 200 F. At temperatures greater than 200 F; tests were conducted at 4,000 psi.

NONE

1997-09-01

350

Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

2013-02-01

351

Stable carbon isotopic compositions of organic acids in total suspended particles and dusts from Guangzhou, China  

NASA Astrophysics Data System (ADS)

Stable carbon isotopic compositions of individual organic acids were determined in total suspended particles and dusts from Guangzhou. The ? 13C values of high molecular weight n-alkanoic acids (C 20-C 28) varied from -34.1‰ to -32.4‰ and tended to be heavier in summer and lighter in winter. These ? 13C values indicate that high molecular weight n-alkanoic acids were derived mainly from emission by C 3 plants. Reduced biological synthesis of high molecular weight n-alkanoic acids in winter may be the reason for the light carbon isotopic composition. The ? 13C values of low molecular weight n-alkanoic acids (C 10-C 18) changed from -31.7‰ to -30.3‰ and exhibited a reverse seasonal trend, i.e., heavier in winter and lighter in summer. Slightly heavier ? 13C values of low molecular weight n-alkanoic acids than those of high molecular weight n-alkanoic acids suggested that they may be emitted from blended sources, e.g., anthropogenic sources and vegetation waxes. Lighter ? 13C values in summer may be attributed to relatively low anthropogenic sources and high botanic sources in summer. Dicarboxylic acids and aromatic acids have been proposed as secondary products from photochemical degradation. The average ? 13C values of dicarboxylic acids and aromatic acids were heavier, and ranged from -25.2‰ to -22.9‰ and from -30.0‰ to -27.6‰, respectively. Both dicarboxylic acids and aromatic acids displayed the same temporal variations in the ? 13C values, i.e., negative ? 13C in the summer samples and positive in the winter samples, which may be controlled by photochemical reactions; they are generally severe in winter in Guangzhou under the monsoon weather system. The heaviest ? 13C values were observed in dicarboxylic acids, indicating that dicarboxylic acids were formed by fast and more complete oxidation reactions. These results indicate that the stable carbon isotopic composition of organic acids may provide important information about sources and photochemical reactions of organic matter in the atmosphere.

Ma, Shexia; Peng, Ping'an; Song, Jianzhong; Zhao, Jinping; He, Lulu; Sheng, Guoying; Fu, Jiamo

2010-10-01

352

Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling  

PubMed Central

Using a pulse chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of rhizosphere soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h) and DNA (30 h) turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 days), while phospholipid fatty acids (PLFAs) had the slowest turnover (42 days). PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings.

Malik, Ashish A.; Dannert, Helena; Griffiths, Robert I.; Thomson, Bruce C.; Gleixner, Gerd

2015-01-01

353

Rheology and Phase Behavior of Single Wall Carbon Nanotube / Strong Acid Systems  

NASA Astrophysics Data System (ADS)

Assessing potential routes to single wall carbon nanotube fiber production requires an understanding of the rheological properties of the dispersions involved. SWNT have been successfully dispersed in strong acids at a wide range of concentrations (0.1 - 10wt%) for fiber production. These SWNT/acid systems exhibit interesting phase behavior analogous to rigid-rod polymer molecule systems, including a liquid crystalline phase. In addition, rheometry experiments reveal the SWNT dispersions to be highly shear-thinning power law liquids.

Pasquali, Matteo; Davis, Virginia A.; Ericson, Lars M.; Smalley, Richard E.; Winey, Karen I.

2002-03-01

354

Carbon nanotubes as electronic interconnects in solid acid fuel cell electrodes.  

PubMed

Carbon nanotubes have been explored as interconnects in solid acid fuel cells to improve the link between nanoscale Pt catalyst particles and macroscale current collectors. The nanotubes were grown by chemical vapor deposition on carbon paper substrates, using nickel nanoparticles as the catalyst, and were characterized using scanning electron microscopy and Raman spectroscopy. The composite electrode material, consisting of CsH2PO4, platinum nanoparticles, and platinum on carbon-black nanoparticles, was deposited onto the nanotube-overgrown carbon paper by electrospraying, forming a highly porous, fractal structure. AC impedance spectroscopy in a symmetric cell configuration revealed a significant reduction of the electrode impedance as compared to similarly prepared electrodes without carbon nanotubes. PMID:23942778

Varga, Áron; Pfohl, Moritz; Brunelli, Nicholas A; Schreier, Marcel; Giapis, Konstantinos P; Haile, Sossina M

2013-10-01

355

Efficient optical resolution of amino acid by alanine racemaze chiral analogue supported on mesoporous carbon  

NASA Astrophysics Data System (ADS)

Optically pure D-amino acids are industrially important chiral building blocks for the synthesis of pharmaceuticals, food ingredients, and drug intermediates. Chemoenzymatic dynamic kinetic-resolution processes have recently been developed for deracemization of amino acids. S-ARCA would be a good candidate for the selective adsorption of D amino acid through the imine formation reaction. The organic phase containing S-ARCA adsorbent, TPPC or Ionic Liquid (as a phase transfer catalyst) in MC were coated on the surfaces of mesoporous carbon C-SBA-15(CMK). The aqueous solution of racemic D/L-amino acid and NaOH were added to the carbon support coated with ARCA. The D/L ratios on ARCA and in solution were determined with increasing reaction time. S-ARCA has a unique property for the selective adsorption of D- amino acid (up to 90% selcetivity) in the racemic mixture. The fixed bed reactor containing ARCA/carbon support was also adopted successfully for the selective separation of amino acid.

Jang, D.; Kim, K.; Park, D.; Kim, G.

2012-09-01

356

Toxicity of pyrolysis gases from polyoxymethylene  

NASA Technical Reports Server (NTRS)

A sample of polyoxymethylene was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. Under several test conditions, this material gave shorter times to death than many other synthetic polymers. Carbon monoxide appeared to be the principal toxicant in the pyrolysis gases.

Hilado, C. J.; Schneider, J. E.; Brauer, D. P.

1979-01-01

357

Modeling and optimizing the design of matrix treatments in carbonate reservoirs with self-diverting acid systems  

NASA Astrophysics Data System (ADS)

Application of a self-diverting-acid based on viscoelastic surfactant (SDVA) is a promising technology for improving the efficacy of acid treatment in oil and gas-bearing carbonate reservoirs. In this study, we present a mathematical model for assessing SDVA flow and reaction with carbonate rock using the SDVA rheological characteristics. The model calculates the technological parameters for acidizing operations and the prediction of well productivity after acid treatment, in addition to technical and economic optimization of the acidizing process by modeling different acid treatment options with varying volumes, injection rates, process fluids stages and initial economic scenarios.

Bulgakova, G. T.; Kharisov, R. Ya; Sharifullin, A. R.; Pestrikov, A. V.

2015-01-01

358

Whole-body pharmacokinetics of HDAC inhibitor drugs, butyric acid, valproic acid and 4-phenylbutyric acid measured with carbon-11 labeled analogs by PET  

PubMed Central

The fatty acids, n-butyric acid (BA), 4-phenylbutyric acid (PBA) and valproic acid (VPA, 2-propylpentanoic acid) have been used for many years in the treatment of a variety of CNS and peripheral organ diseases including cancer. New information that these drugs alter epigenetic processes through their inhibition of histone deacetylases (HDACs) has renewed interest in their biodistribution and pharmacokinetics and the relationship of these properties to their therapeutic and side effect profile. In order to determine the pharmacokinetics and biodistribution of these drugs in primates, we synthesized their carbon-11 labeled analogues and performed dynamic positron emission tomography (PET) in six female baboons over 90 min. The carbon-11 labeled carboxylic acids were prepared by using 11CO2 and the appropriate Grignard reagents. [11C]BA was metabolized rapidly (only 20% of the total carbon-11 in plasma was parent compound at 5 min post injection) whereas for VPA and PBA 98% and 85% of the radioactivity was the unmetabolized compound at 30 min after their administration respectively. The brain uptake of all three carboxylic acids was very low (<0.006%ID/cc, BA>VPA>PBA), which is consistent with the need for very high doses for therapeutic efficacy. Most of the radioactivity was excreted through the kidneys and accumulated in the bladder. However, the organ biodistribution between the drugs differed. [11C]BA showed relatively high uptake in spleen and pancreas whereas [11C]PBA showed high uptake in liver and heart. Notably, [11C]VPA showed exceptionally high heart uptake possibly due to its involvement in lipid metabolism. The unique biodistribution of each of these drugs may be of relevance in understanding their therapeutic and side effect profile including their teratogenic effects. PMID:23906667

Kim, Sung Won; Hooker, Jacob M.; Otto, Nicola; Win, Khaing; Muench, Lisa; Shea, Colleen; Carter, Pauline; King, Payton; Reid, Alicia E.; Volkow, Nora D.; Fowler, Joanna S.

2013-01-01

359

Synergistic effect of self-assembled carboxylic acid-functionalized carbon nanotubes and carbon fiber for improved electro-activated polymeric shape-memory nanocomposite  

NASA Astrophysics Data System (ADS)

The present work studies the synergistic effect of self-assembled carboxylic acid-functionalized carbon nanotube (CNT) and carbon fiber on the electrical property and electro-activated recovery behavior of shape memory polymer (SMP) nanocomposites. The combination of CNT and carbon fiber results in improved electrical conductivity in the SMP nanocomposites. Carboxylic acid-functionalized CNTs are grafted onto the carbon fibers and then self-assembled by deposition to significantly enhance the reliability of the bonding between carbon fiber and SMP via van der Waals and covalent crosslink. Furthermore, the self-assembled carboxylic acid-functionalized CNTs and carbon fibers enable the SMP nanocomposites for Joule heating triggered shape recovery.

Lu, Haibao; Min Huang, Wei

2013-06-01

360

On the abiotic formation of amino acids I. HCN as a precursor of amino acids detected in extracts of lunar samples II. Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples  

Microsoft Academic Search

Summary Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is

S. Yuasa; D. Flory; B. Basile; J. Oró

1984-01-01

361

Carbon isotope and abundance systematics of Icelandic geothermal gases, fluids and subglacial basalts with implications for mantle plume-related CO2 fluxes  

NASA Astrophysics Data System (ADS)

We report new carbon dioxide (CO2) abundance and isotope data for 71 geothermal gases and fluids from both high-temperature (HT > 150 °C at 1 km depth) and low-temperature (LT < 150 °C at 1 km depth) geothermal systems located within neovolcanic zones and older segments of the Icelandic crust, respectively. These data are supplemented by CO2 data obtained by stepped heating of 47 subglacial basaltic glasses collected from the neovolcanic zones. The sample suite has been characterized previously for He-Ne (geothermal) and He-Ne-Ar (basalt) systematics (Füri et al., 2010), allowing elemental ratios to be calculated for individual samples. Geothermal fluids are characterized by a wide range in carbon isotope ratios (?13C), from -18.8‰ to +4.6‰ (vs. VPDB), and CO2/3He values that span eight orders of magnitude, from 1 × 104 to 2 × 1012. Extreme geothermal values suggest that original source compositions have been extensively modified by hydrothermal processes such as degassing and/or calcite precipitation. Basaltic glasses are also characterized by a wide range in ?13C values, from -27.2‰ to -3.6‰, whereas CO2/3He values span a narrower range, from 1 × 108 to 1 × 1012. The combination of both low ?13C values and low CO2 contents in basalts indicates that magmas are extensively and variably degassed. Using an equilibrium degassing model, we estimate that pre-eruptive basaltic melts beneath Iceland contain ?531 ± 64 ppm CO2 with ?13C values of -2.5 ± 1.1‰, in good agreement with estimates from olivine-hosted melt inclusions (Metrich et al., 1991) and depleted MORB mantle (DMM) CO2 source estimates (Marty, 2012). In addition, pre-eruptive CO2 compositions are estimated for individual segments of the Icelandic axial rift zones, and show a marked decrease from north to south (Northern Rift Zone = 550 ± 66 ppm; Eastern Rift Zone = 371 ± 45 ppm; Western Rift Zone = 206 ± 24 ppm). Notably, these results are model dependent, and selection of a lower ?13C fractionation factor will result in lower source estimates and larger uncertainties associated with the initial ?13C estimate. Degassing can adequately explain low CO2 contents in basalts; however, degassing alone is unlikely to generate the entire spectrum of observed ?13C variations, and we suggest that melt-crust interaction, involving a low ?13C component, may also contribute to observed signatures. Using representative samples, the CO2 flux from Iceland is estimated using three independent methods: (1) combining measured CO2/3He values (in gases and basalts) with 3He flux estimates (Hilton et al., 1990), (2) merging basaltic emplacement rates of Iceland with pre-eruptive magma source estimates of ?531 ± 64 ppm CO2, and (3) combining fluid CO2 contents with estimated regional fluid discharge rates. These methods yield CO2 flux estimates from of 0.2-23 × 1010 mol a-1, which represent ?0.1-10% of the estimated global ridge flux (2.2 × 1012 mol a-1; Marty and Tolstikhin, 1998).

Barry, P. H.; Hilton, D. R.; Füri, E.; Halldórsson, S. A.; Grönvold, K.

2014-06-01

362

Acid rain damage to carbonate stone: a quantitative assessment based on the aqueous geochemistry of rainfall runoff from stone  

USGS Publications Warehouse

An onsite experimental procedure was used to identify and quantify acid rain damage to carbonate stone, based on the change in rain runoff chemical composition. Onsite data obtained during the summer and fall of 1984 at three locations in the northeastern United States indicate that carbonate stone surface recession is related to acid deposition. -from Author

Reddy, M.M.

1988-01-01

363

The formation of amino acid precursors in the reaction of atomic carbon with water and ammonia at 77 K  

Microsoft Academic Search

When atomic carbon is condensed on a surface at 77 K containing ammonia and water, glycine, N-methylglycine, alanine, beta-alanine, aspartic acid and serine are generated. It is postulated that these reactions may mimic those which occur when an extraterrestrial carbon atom condenses on a frozen surface coated with water and ammonia and may provide a route to extraterrestrial amino acids.

Daniel W. McPherson; Kazi Rahman; Iris Martinez; Philip B. Shevlin

1987-01-01

364

Sources of black carbon aerosols in South Asia and surrounding regions during the Integrated Campaign for Aerosols, Gases and Radiation Budget (ICARB)  

NASA Astrophysics Data System (ADS)

The dominant sources of black carbon (BC) in South Asia and surrounding regions are inferred during March-May 2006 (Integrated Campaign for Aerosols, Gases and Radiation Budget, ICARB) period by introducing BC tracers in the Weather Research and Forecasting Model coupled with Chemistry. The model reproduced the magnitude, temporal and spatial variability of BC distribution observed during the ICARB ship-cruise. Average and SD (representing the spatial and temporal variability) in observed and modeled BC mass concentrations along the ship-track are estimated as 755 ± 734 and 732 ± 913 ng m-3 respectively. Average modeled values at most of the inland stations were also found to fall within the range of observed values. Model results show that ICARB measurements were fairly well representative of the Arabian Sea and the Bay of Bengal during the pre-monsoon season. Results show that anthropogenic and biomass burning emissions, respectively, accounted for 70 and 28 % of the average ± SD BC mass concentration (1480 ± 5920 ng m-3) in South Asia. BC emissions from residential (49 %) and industrial (37 %) sectors appear to be the major anthropogenic sources, except in the Himalayas where vehicular emissions dominated. We find that, while all parts of continental India contributed to anthropogenic BC over the Bay of Bengal, contribution over the Arabian Sea came mostly from southern Peninsula. We also show that regional-scale transport of anthropogenic emissions contribute up to 30 % of BC mass concentrations in western and eastern India, suggesting that it is important to consider non-local sources along with the local emissions while designing strategies for mitigating BC emissions.

Kumar, R.; Barth, M. C.; Nair, V. S.; Pfister, G. G.; Babu, S. S.; Satheesh, S. K.; Moorthy, K. K.; Carmichael, G. R.

2014-12-01

365

Carbon Isotopic Ratios of Amino Acids in Stardust-Returned Samples  

NASA Technical Reports Server (NTRS)

NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here. we present the carbon isotopic ratios of glycine and E-aminocaproic acid (EACH), the two most abundant amino acids observed, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio crass spectrometry coupled with quadrupole mass spectrometry (GC-QMS/IRMS).

Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

2009-01-01

366

Carbon Isotopic Measurements of Amino Acids in Stardust-Returned Samples  

NASA Technical Reports Server (NTRS)

NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here, we present the carbon isotopic ratios of glycine and e-aminocaproic acid (EACA), the two most abundant amino acids, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio mass spectrometry coupled with quadrupole mass spectrometry (GC-CAMS/IRMS).

Elsila, Jamie

2009-01-01

367

Microbial mediated formation of Fe-carbonate minerals under extreme acidic conditions  

NASA Astrophysics Data System (ADS)

Discovery of Fe-carbonate precipitation in Rio Tinto, a shallow river with very acidic waters, situated in Huelva, South-western Spain, adds a new dimension to our understanding of carbonate formation. Sediment samples from this low-pH system indicate that carbonates are formed in physico-chemical conditions ranging from acid to neutral pH. Evidence for microbial mediation is observed in secondary electron images (Fig. 1), which reveal rod-shaped bacteria embedded in the surface of siderite nanocrystals. The formation of carbonates in Rio Tinto is related to the microbial reduction of ferric iron coupled to the oxidation of organic compounds. Herein, we demonstrate for the first time, that Acidiphilium sp. PM, an iron-reducing bacterium isolated from Rio Tinto, mediates the precipitation of siderite (FeCO3) under acidic conditions and at a low temperature (30°C). We describe nucleation of siderite on nanoglobules in intimate association with the bacteria cell surface. This study has major implications for understanding carbonate formation on the ancient Earth or extraterrestrial planets.

Sánchez-Román, Mónica; Fernández-Remolar, David; Amils, Ricardo; Sánchez-Navas, Antonio; Schmid, Thomas; Martin-Uriz, Patxi San; Rodríguez, Nuria; McKenzie, Judith A.; Vasconcelos, Crisogono

2014-04-01

368

Microbial mediated formation of Fe-carbonate minerals under extreme acidic conditions  

PubMed Central

Discovery of Fe-carbonate precipitation in Rio Tinto, a shallow river with very acidic waters, situated in Huelva, South-western Spain, adds a new dimension to our understanding of carbonate formation. Sediment samples from this low-pH system indicate that carbonates are formed in physico-chemical conditions ranging from acid to neutral pH. Evidence for microbial mediation is observed in secondary electron images (Fig. 1), which reveal rod-shaped bacteria embedded in the surface of siderite nanocrystals. The formation of carbonates in Rio Tinto is related to the microbial reduction of ferric iron coupled to the oxidation of organic compounds. Herein, we demonstrate for the first time, that Acidiphilium sp. PM, an iron-reducing bacterium isolated from Rio Tinto, mediates the precipitation of siderite (FeCO3) under acidic conditions and at a low temperature (30°C). We describe nucleation of siderite on nanoglobules in intimate association with the bacteria cell surface. This study has major implications for understanding carbonate formation on the ancient Earth or extraterrestrial planets. PMID:24755961

Sánchez-Román, Mónica; Fernández-Remolar, David; Amils, Ricardo; Sánchez-Navas, Antonio; Schmid, Thomas; Martin-Uriz, Patxi San; Rodríguez, Nuria; McKenzie, Judith A.; Vasconcelos, Crisogono

2014-01-01

369

FATTY ACID STABLE ISOTOPE INDICATORS OF MICROBIAL CARBON SOURCE IN TROPICAL SOILS  

EPA Science Inventory

The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

370

SURFACE AREA MEASUREMENT BY THE SORPTION OF STEARIC ACID1CARBON14  

Microsoft Academic Search

A technique was developed for determimng the surface area of non-porous ; powders by their sorption of stearic acid-l-carbon-14 from benzene solutions. ; Aliquots of the initial solution and of the solution in equilibrium with a sample ; were plated on chilled watch glasses and assayed by thin end-window Geiger ; counters. Specific surface areas obtained by this method for

M. C. Kordecki; M. B. Gandy

1961-01-01

371

EFFECT OF ACID TREATMENT ON DISSOLVED ORGANIC CARBON RETENTION BY A SPODIC HORIZON  

EPA Science Inventory

Processes involving the movement of organic substances in forest soils are not well understood. This study was conducted to examine the role of acidic inputs on dissolved organic carbon (DOC) mobility, processes affecting the retention of DOV by a B horizon, and SO2-4 adsorption....

372

Titration of Monoprotic Acids with Sodium Hydroxide Contaminated by Sodium Carbonate.  

ERIC Educational Resources Information Center

Discusses the effects of using carbon dioxide contaminated sodium hydroxide solution as a titrant for a solution of a weak monoprotic acid and the resulting distortion of the titration curve in comparison to one obtained when an uncontaminated titrant is used. (CW)

Michalowski, Tadeusz

1988-01-01

373

Simultaneous requirement of carbon dioxide and abscisic acid for stomatal closing in Xanthium strumarium L  

Microsoft Academic Search

Open stomata of detached leaves of Xanthium strumarium L. closed only when carbon dioxide and abscisic acid (ABA) were presented simultaneously. Three parameters of stomatal closing were determined after additions of ABA to the irrigation water of detached leaves, while the leaves were exposed to various CO2 concentrations ([CO2]s) in the air; a) the delay between addition of ABA and

Klaus Raschke

1975-01-01

374

Formic acid electro-synthesis from carbon dioxide in a room temperature ionic liquid.  

PubMed

The novel synthesis of formic acid has been achieved in a room temperature ionic liquid via the reaction of electro-activated carbon dioxide and protons on pre-anodised platinum. Only mild reaction conditions of room temperature and 1 atm CO(2) were used. This work highlights the effect of pre-anodisation on Pt surfaces. PMID:22622393

Martindale, Benjamin C M; Compton, Richard G

2012-07-01

375

Generation of aliphatic acid anions and carbon dioxide by hydrous pyrolysis of crude oils  

USGS Publications Warehouse

Two crude oils with relatively high (0.60 wt%) and low (0.18 wt%) oxygen contents were heated in the presence of water in gold-plated reactors at 300??C for 2348 h. The high-oxygen oil was also heated at 200??C for 5711 h. The compositions of aqueous organic acid anions of the oils and of the headspace gases were monitored inn order to investigate the distribution of organic acids that can be generated from liquid petroleum. The oil with higher oxygen content generated about five times as much organic anions as the other oil. The dominant organic anions produced were acetate, propionate and butyrate. Small amounts of formate, succinate, methyl succinate and oxalate were also produced. The dominant oxygen-containing product was CO2, as has been observed in similar studies on the hydrous pyrolysis of kerogen. These results indicate that a significant portion (10-30%) of organic acid anions reported i be generated by thermal alteration of oils in reservoir rocks. The bulk of organic acid anions present in formation waters, however, is most likely generated by thermal alteration of kerogen in source rocks. Kerogen is more abundant than oil in sedimentary basins and the relative yields of organic acid anions reported from the hydrous pyrolysis of kerogen are much higher than the yields obtained for the two oils. ?? 1993.

Kharaka, Y.K.; Lundegard, P.D.; Ambats, G.; Evans, William C.; Bischoff, J.L.

1993-01-01

376

Greenhouse Gases  

NSDL National Science Digital Library

Explore how the Earth's atmosphere affects the energy balance between incoming and outgoing radiation. Using an interactive model, adjust realistic parameters such as how many clouds are present or how much carbon dioxide is in the air, and watch how these factors affect the global temperature.

2012-07-19

377

Solubility of Small-Chain Carboxylic Acids in Supercritical Carbon Dioxide  

SciTech Connect

The solubility of heptanoic acid and octanoic acid in supercritical carbon dioxide has been determined at temperatures of (313.15, 323.15, and 333.15) K over a pressure range of (8.5 to 30.0) MPa, depending upon the solute. The solubility of heptanoic acid ranged from a solute concentration of (0.08 ± 0.03) kg�m -3 (T = 323.15 K, p = 8.5 MPa) to (147 ± 0.2) kg�m -3 (T = 323.15 K, p = 20.0 MPa). The lowest octanoic acid solubility obtained was a solute concentration of (0.40 ± 0.1) kg�m -3 (T = 333.15 K, p = 10.0 MPa), while the highest solute concentration was (151 ± 2) kg�m -3 (T = 333.15 K, p = 26.7 MPa). Additionally, solubility experiments were performed for nonanoic acid in supercritical carbon dioxide at 323.15 K and pressures of (10.0 to 30.0) MPa to add to the solubility data previously published by the authors. In general, carboxylic acid solubility increased with increasing solvent density. The results also showed that the solubility of the solutes decreased with increasing molar mass at constant supercritical-fluid density. Additionally, the efficacy of Chrastil's equation and other density-based models was evaluated for each fatty acid.

Sparks, Darrell L.; Estevez, L. Antonio; Hernandez, Rafael; McEwen, Jason; French, Todd

2010-07-08

378

Preliminary simulations of planned experiments to study the impact of trace gases on the capacity of the Weyburn-Midale field to store carbon dioxide  

SciTech Connect

The CO{sub 2} stream injecting into the Weyburn-Midale field can be generally classified as a reducing stream with residual H{sub 2}S and low-molecular weight hydrocarbons. The composition of the CO{sub 2} gas stream from the Dakota Gasification Company is reported to be 95% CO{sub 2}, 4% hydrocarbons, and 1% H{sub 2}S by volume (Huxley 2006). In addition to the H{sub 2}S introduced at the injection wells, significant concentrations of H{sub 2}S are thought to have been produced in-situ by sulfate reducing bacteria from previous water floods for enhanced oil production. Produced gas compositions range in H{sub 2}S concentrations from 1 to 6 volume percent. The produced gas, including the trace impurities, is re-injected into the field. Although there is no evidence for inorganic reduction of SO{sub 4}{sup 2-} to H{sub 2}S at the Weyburn-Midale field, Sitchler and Kazuba (2009) suggest that SO{sub 4}{sup 2-} can be inorganically reduced to elemental sulfur in highly reducing environments based on a natural analog study of the Madison Formation in Wyoming. They propose that elevated concentrations of CO{sub 2} dissolve anhydrite to produce the sulfate that is then reduced. Oxidizing CO{sub 2} streams with residual O{sub 2} and SO{sub 2} typical of streams captured from oxyfuel and post combustion processes are not presently an issue at the Weyburn-Midale field. However it is possible that the oxidizing CO{sub 2} streams may be injected in the future in carbonate reservoirs similar to the Weyburn-Midale field. To date there are few modeling and experimental studies that have explored the impact of impurity gases in CO{sub 2} streams targeted for geologic storage (Gale 2009). Jacquemet et al (2009) reviewed select geochemical modeling studies that explored the impact of SO{sub 2} and H{sub 2}S impurities in the waste streams (Gunter et al., 2000, Knauss et al., 2005, Xu et al., 2007). These studies collectively show that SO{sub 2} significantly reduces the pH when oxidized to H{sub 2}SO{sub 4} causing enhanced dissolution of carbonate minerals and some sulfate mineral precipitation. Low pH results in higher mineral solubility and faster dissolution rates and is thought to enhance porosity and permeability near the injection well when trace amounts of SO{sub 2} is injected with CO{sub 2}. The impact of H{sub 2}S on storage reservoir performance appears to more subtle. Knauss et al (2005) report no significant impacts of injection of CO{sub 2} gas streams with and without H{sub 2}S (1 M Pascal H{sub 2}S + 8.4 M Pascal CO{sub 2}) in simulations of CO{sub 2} storage in the Frio sandstone formation. Geochemical reactions for H{sub 2}S impurities include enhance field alkalinity and reaction with iron bearing minerals that may delay breakthrough of H{sub 2}S relative to CO{sub 2}. Emberley et al. (2005) report that half of the alkalinity measured at monitoring wells at the Weyburn-Midale field is due to HS{sup -}. Schoonen and Xu (2004) report that H{sub 2}S can be sequestered as pyrite in sandstones and carbonates by dissolving iron hydroxides and iron-bearing clays. Similarly, Gunter et al (2000) propose the that siderite converts to iron sulfides when it is reacted with H{sub 2}S. The geochemical reactions between H{sub 2}S and iron bearing minerals together with the high solubility of H{sub 2}S relative to CO{sub 2} may contribute to the delayed break though of H{sub 2}S in experiments. A few core flood experiments have shown that the injection of supercritical CO{sub 2} into carbonate aquifers has the potential to significantly alter the porosity in the absence of trace gases such as SO{sub 2} and H{sub 2}S. Luquot and Gouze (2009) documented a 2% porosity increase in carbonate cores when rock-water interactions were transport limited and solution concentrations were closer to equilibrium and a 4% porosity increase when rock-water interactions were reaction limited and solution compositions were further from equilibrium. Similarly Le Guen et al (2007) used x-ray micro-tomography and geochemistry to show that porosity signific

Carroll, S; Hao, Y

2009-11-13

379

Artificial photosynthesis of. beta. -ketocarboxylic acids from carbon dioxide and ketones via enolate complexes of aluminum porphyrin  

Microsoft Academic Search

Photochemical fixation of carbon dioxide is of much interest in connection with biological photosynthesis by green plants as well as from the viewpoint of carbon resource utilization. One of the important steps in the assimilation of carbon dioxide is the carboxylation of a carbonyl compound into ketocarboxylic acid, where the reaction proceeds via an enolate species as reactive intermediate. For

Yasuhiro Hirai; Takuzo Aida; Shohei Inoue

1989-01-01

380

Kinetics of dodecanoic acid adsorption from caustic solution by activated carbon.  

PubMed

This study examines the influences of adsorbent porosity and surface chemistry and of carbon dosage on dodecanoic acid adsorption kinetics from aqueous and 2 M NaOH solutions as batch adsorption processes. Both adsorbents are steam-activated carbons prepared from either coconut or coal precursors. Prior to use the adsorbents were washed in deionized water or 2 M NaOH. Mass transfer coefficients and effective overall diffusion coefficients indicate a minor contribution from adsorbent porosity. In contrast, high surface oxygen content impedes transport to and into the adsorbent structure. Carbon dosage shows a proportional increase in transport coefficients with increasing mass; these coefficients are constant when normalized per unit mass. Neither water nor NaOH treatment of the adsorbents has a significant influence on dodecanoic acid adsorption kinetics. Molecular and Knudsen diffusion coefficients are defined to demonstrate that the overall effective diffusion coefficient values and the diffusion process are controlled by surface diffusion. PMID:14527446

Pendleton, Phillip; Wu, Sophie Hua

2003-10-15

381

Synthesis of sulfonated porous carbon nanospheres solid acid by a facile chemical activation route  

NASA Astrophysics Data System (ADS)

Generally, porous carbon nanospheres materials are usually prepared via a template method, which is a multi-steps and high-cost strategy. Here, we reported a porous carbon nanosphere solid acid with high surface area and superior porosity, as well as uniform nanospheical morphology, which prepared by a facile chemical activation with ZnCl2 using resorcinol-formaldehyde (RF) resins spheres as precursor. The activation of RF resins spheres by ZnCl2 at 400 °C brought high surface area and large volume, and simultaneously retained numerous oxygen-containing and hydrogen-containing groups due to the relatively low processing temperature. The presence of these functional groups is favorable for the modification of -SO3H groups by a followed sulfonation treating with sulphuric acid and organic sulfonic acid. The results of N2 adsorption-desorption and electron microscopy clearly showed the preservation of porous structure and nanospherical morphology. Infrared spectra certified the variation of surface functional groups after activation and the successful modification of -SO3H groups after sulfonation. The acidities of catalysts were estimated by an indirect titration method and the modified amount of -SO3H groups were examined by energy dispersive spectra. The results suggested sulfonated porous carbon nanospheres catalysts possessed high acidities and -SO3H densities, which endowed their significantly catalytic activities for biodiesel production. Furthermore, their excellent stability and recycling property were also demonstrated by five consecutive cycles.

Chang, Binbin; Guo, Yanzhen; Yin, Hang; Zhang, Shouren; Yang, Baocheng

2015-01-01

382

Acceleration of carbon-13 spin-lattice relaxation times in amino acids by electrolytes.  

PubMed

Measurements of the enhancement, by various electrolytes, of the spin-lattice relaxation time of carbon-13 at different locations in a number of amino acids are reported. Spin-lattice relaxation times T1 of all the carbons in amino acids generally tend to decrease with increase in the concentration of electrolytes, the largest effects often being observed for the charged carboxylate groups of the amino acids. Carboxylic carbons in amino acids are the sensitive 'acceptor' of the 13C spin-lattice relaxation accelerating effects offered by electrolytes, and the 13C spin-lattice relaxation accelerating ability of electrolytes decreases in the order Mg(ClO4)2 > MgCl2 > CaCl2 > NaCl > KCl > LiClO4 > NaOH. The mechanisms of the observed phenomena are discussed in terms of intermolecular interaction, paramagnetic impurities in electrolytes and other mechanisms; large contributions of intermolecular interactions with electrolytes are present on complex formation between amino acids and metal ions and the incoming 'unsaturation' of the primary solvation shell of cations with the increase in electrolyte concentration. PMID:15181635

Tian, Jinping; Yin, Yingwu

2004-07-01

383

[Studies on carbonization of saccharides by using aqueous solution of various acids].  

PubMed

The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol · L(-1) acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease compared with pure 2-deoxy-ribose and fructose. In the XPS spectra, the is peaks of 2-deoxy-ribose, strong sub peak at 286. 05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C is peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1 600 cm(-1), indicating that C==C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency. PMID:25532323

Zhang, Xin; He, An-Qi; Kang, Ting-Guo; Xia, Jin-Ming; Weng, Shi-Fu; Xu, Yi-Zhuang; Wu, Jin-Guang

2014-09-01

384

Stable carbon isotopic compositions of total carbon, dicarboxylic acids and glyoxylic acid in the tropical Indian aerosols: Implications for sources and photochemical processing of organic aerosols  

NASA Astrophysics Data System (ADS)

The tropical Indian aerosols (PM10) collected on day- and nighttime bases in winter and summer, 2007 from Chennai (13.04°N; 80.17°E) were studied for stable carbon isotopic compositions (?13C) of total carbon (TC), individual dicarboxylic acids (C2-C9) and glyoxylic acid (?C2). ?13C values of TC ranged from -23.9‰ to -25.9‰ (-25.0 ± 0.6‰; n = 49). Oxalic (C2) (-17.1 ± 2.5‰), malonic (C3) (-20.8 ± 1.8‰), succinic (C4) (-22.5 ± 1.5‰) and adipic (C6) (-20.6 ± 4.1‰) acids and ?C2 acid (-22.4 ± 5.5‰) were found to be more enriched with 13C compared to TC. In contrast, suberic (C8) (-29.4 ± 1.8‰), phthalic (Ph) (-30.1 ± 3.5‰) and azelaic (C9) (-28.4 ± 5.8‰) acids showed smaller ?13C values than TC. Based on comparisons of ?13C values of TC in Chennai aerosols to those (-24.7 ± 2.2‰) found in unburned cow-dung samples collected from Chennai and isotopic signatures of the particles emitted from point sources, we found that biofuel/biomass burning are the major sources of carbonaceous aerosols in South and Southeast Asia. The decrease in ?13C values of C9 diacid by about 5‰ from winter to summer suggests that tropical plant emissions also significantly contribute to organic aerosol in this region. Significant increase in ?13C values from C4 to C2 diacids in Chennai aerosols could be attributed for their photochemical processing in the tropical atmosphere during long-range transport from source regions.

Pavuluri, Chandra Mouli; Kawamura, Kimitaka; Swaminathan, T.; Tachibana, Eri

2011-09-01

385

Controlled exposures of volunteers to respirable carbon and sulfuric acid aerosols  

SciTech Connect

Respirable carbon or fly ash particles are suspected to increase the respiratory toxicity of coexisting acidic air pollutants, by concentrating acid on their surfaces and so delivering it efficiently to the lower respiratory tract. To investigate this issue, the authors exposed 15 healthy and 15 asthmatic volunteers in a controlled-environment chamber to four test atmospheres: (1) clean air; (2) 0.5-{mu}m H{sub 2}SO{sub 4} aerosol at {approx}100 {mu}g/m{sup 3}, generated from water solution; (3) 0.5-{mu}m carbon aerosol at {approx}250 {mu}g/m{sup 3}, generated from highly pure carbon black with specific surface area comparable to ambient pollution particles; and (4) carbon as in (3) plus {approx}100 {mu}g/m{sup 3} of ultrafine H{sub 2}SO{sub 4} aerosol generated from fuming sulfuric acid. Electron microscopy showed that nearly all acid in (4) became attached to carbon particle surfaces, and that most particles remained in the sub-{mu}m size range. Exposures were performed double-blind, 1 week apart. They lasted 1 hr each, with alternate 10-min periods of heavy exercise (ventilation {approx}50 L/min) and rest. Subjects gargled citrus juice before exposure to suppress airway ammonia. Lung function and symptoms were measured pre-exposure, after initial exercise, and at end-exposure. Bronchial reactivity to methacholine was measured after exposure. Statistical analyses tested for effects of H{sub 2}SO{sub 4} or carbon, separate or interactive, on health measures.

Anderson, K.R.; Avol, E.L.; Edwards, S.A.; Shamoo, D.A.; Ruchuan Peng; Linn, W.S.; Hackney, J.D. (Univ. of Southern California, Downey (United States))

1992-06-01

386

Matrix Isolation Studies of Carbonic Acid—The Vapor Phase above the ?-Polymorph  

PubMed Central

Twenty years ago two different polymorphs of carbonic acid, ?- and ?-H2CO3, were isolated as thin, crystalline films. They were characterized by infrared and, of late, by Raman spectroscopy. Determination of the crystal structure of these two polymorphs, using cryopowder and thin film X-ray diffraction techniques, has failed so far. Recently, we succeeded in sublimating ?-H2CO3 and trapping the vapor phase in a noble gas matrix, which was analyzed by infrared spectroscopy. In the same way we have now investigated the ?-polymorph. Unlike ?-H2CO3, ?-H2CO3 was regarded to decompose upon sublimation. Still, we have succeeded in isolation of undecomposed carbonic acid in the matrix and recondensation after removal of the matrix here. This possibility of sublimation and recondensation cycles of ?-H2CO3 adds a new aspect to the chemistry of carbonic acid in astrophysical environments, especially because there is a direct way of ?-H2CO3 formation in space, but none for ?-H2CO3. Assignments of the FTIR spectra of the isolated molecules unambiguously reveal two different carbonic acid monomer conformers (C2v and Cs). In contrast to the earlier study on ?-H2CO3, we do not find evidence for centrosymmetric (C2h) carbonic acid dimers here. This suggests that two monomers are entropically favored at the sublimation temperature of 250 K for ?-H2CO3, whereas they are not at the sublimation temperature of 210 K for ?-H2CO3. PMID:23631554

2013-01-01

387

Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves.  

PubMed

Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H2O and CO2. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16-33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. PMID:24582232

Gallyamov, Marat O; Chaschin, Ivan S; Khokhlova, Marina A; Grigorev, Timofey E; Bakuleva, Natalia P; Lyutova, Irina G; Kondratenko, Janna E; Badun, Gennadii A; Chernysheva, Maria G; Khokhlov, Alexei R

2014-04-01

388

Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups  

SciTech Connect

Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

Fifield, Leonard S.; Grate, Jay W.

2010-06-01

389

Solubilities of stearic acid, stearyl alcohol, and arachidyl alcohol in supercritical carbon dioxide at 35[degree]C  

SciTech Connect

The solubilities of stearic acid (octadecanoic acid), stearyl alcohol (1-octadecanol), and arachidyl alcohol (1-eicosanol) in supercritical carbon dioxide were measured by using a flow-type apparatus at 35 C up to 23.7 MPa. The solubilities of those substances and other fatty acids and higher alcohols in supercritical carbon dioxide at 35 C were correlated by a solution model based on the regular solution model coupled with the Flory-Huggins theory.

Iwai, Yoshio; Koga, Yoshio; Maruyama, Hironori; Arai, Yasuhiko (Kyushu Univ., Fukuoka (Japan). Dept. of Chemical Engineering)

1993-10-01

390

Reaction rate vs. transport limited dissolution during carbonate acidizing: Application of network model  

SciTech Connect

Coreflood experiments have been performed and a two dimensional network model has been developed to study the flow, dissolution, and permeability increase in carbonates during acid stimulation treatments. The goal is to be able to predict the behaviour of the random flow channels, called wormholes, that form in the rock as a result of acid attack. Understanding this channeling phenomenon is essential in predicting acid penetration distances and the resulting injectivity or productivity increases during matrix acidizing, or in understanding acid leakoff behaviour during fracture acidizing. Until now, relatively little has been known about the wormholing phenomenon because of the stochastic nature of channel formation and the inherent difficulty in modelling the random behaviour. Model predictions and experimental coreflood results are compared for linear systems. The model predicts wormholing and the effects of acidizing parameters such as fluid velocity, mineral dissolution rate, and rock properties on channel structure and the corresponding rate of channel propagation. Experimental data and model prediction support the conclusion that wormholing is necessary for matrix treatment effectiveness, but does not occur for the extremes of high and low values of the Damkohler number for flow and reaction, which controls the process. The model thus accounts for the ineffectiveness of aqueous hydrochloric acid for matrix treatments in limestone due to rapid acid spending, and for the possible ineffectiveness of treatments in dolomite due to mineral dissolution rates that are too slow to promote channel formation.

Hoefner, M.L.; Fogler, H.S.

1986-01-01

391

Vertically aligned carbon nanofiber electrode arrays for nucleic acid detection  

NASA Astrophysics Data System (ADS)

We present electrochemical detection of DNA targets that corresponds to Escherichia coli O157:H7 16S rRNA gene using a nanoelectrode array consisting of vertically aligned carbon nanofiber (VACNF) electrodes. Parylene C is used as gap filling 'matrix' material to avoid high temperature processing in electrode construction. This easy to deposit film of several micron heights provides a conformal coating between the high aspect ratio VACNFs with negligible pin-holes. The low background currents show the potential of this approach for ultra-sensitive detection. Consistent and reproducible electrochemical-signals are achieved using a simple electrode preparation. This simple, reliable and low-cost approach is a forward step in developing practical sensors for applications like pathogen detection, early cancer diagnosis and environmental monitoring.

Arumugam, Prabhu U.; Yu, Edmond; Riviere, Roger; Meyyappan, M.

2010-10-01

392

SORPTION OF MERCURY SPECIES BY ACTIVATED CARBONS AND CALCIUM-BASES SORBENTS: EFFECT OF TEMPERATURE, MERCURY CONCENTRATION AND ACID GASES  

EPA Science Inventory

Bench-scale studies of mercury/sorbent reactions were conducted to understand mechanistic limitations of field-scale attempts to reduce emissions of mercury from combustion processes. The effects of temperature (60 - 140 degrees C), sulfur dioxide (SO2, 1000 ppm ), hydrogen chlor...

393

Amperometric uric acid biosensor based on poly(vinylferrocene)-gelatin-carboxylated multiwalled carbon nanotube modified glassy carbon electrode.  

PubMed

In this study, a new uric acid biosensor was constructed based on ferrocene containing polymer poly(vinylferrocene) (PVF), carboxylated multiwalled carbon nanotubes (c-MWCNT) and gelatin (GEL) modified glassy carbon electrode (GCE). Uricase enzyme (UOx) was immobilized covalently through N-ethyl-N'-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxyl succinimide (NHS) chemistry onto c-MWCNT/GEL/PVF/GCE. The c-MWCNT/GEL/PVF composite was characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters such as pH, applied potential, enzyme loading, PVF and c-MWCNT concentration were investigated in detail. Under the optimal conditions the dynamic linear range of uric acid was 2.0×10(-7) M-7.1×10(-4) M (R=0.9993) with the detection limit low to 2.3×10(-8) M. With good selectivity and sensitivity, the biosensor was successfully applied to determine the uric acid in human serum. The results of the biosensor were in good agreement with those obtained from standard method. Therefore, the presented biosensor could be a good promise for practical applications in real samples. PMID:25618698

Erden, P?nar Esra; Kaçar, Ceren; Öztürk, Funda; K?l?ç, Esma

2015-03-01

394

Solids Liquids and Gases  

NSDL National Science Digital Library

Compare and contrast the three states of matter: solids, liquids and gases. First you will begin by looking at characteristics of each solids, liquids and gasesGases, Liquids and Solids Facts. Then you will look at examples of each stateSolids, Liquids and Gases Video. Demonstrate an understanding of solids, liquids and gases by playing interactive gameSolids, Liquids and Gases Game. Graphic Organizer is here to be filled out as you learn during this lesson. Use the red ...

Ms. Salter

2009-10-22

395

On the abiotic formation of amino acids. I - HCN as a precursor of amino acids detected in extracts of lunar samples. II - Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples  

NASA Technical Reports Server (NTRS)

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.

Yuasa, S.; Flory, D.; Basile, B.; Oro, J.

1984-01-01

396

On the abiotic formation of amino acids. I. HCN as a precursor of amino acids detected in extracts of lunar samples. II. Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples.  

PubMed

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water. PMID:6330374

Yuasa, S; Flory, D; Basile, B; Oró, J

1984-01-01

397

Effect of Nitric Acid “Washing” Procedure on Electrochemical Behavior of Carbon Nanotubes and Glassy Carbon ?-Particles  

PubMed Central

The electroanalytic performances of glassy carbon paste electrode (GCPE), multi-walled carbon nanotube (MWCNT)-GCPE and double-walled carbon nanotube (DWCNT)-GCPE, which include HNO3 washed/unwashed materials, were compared by monitoring cyclic voltammograms of potassium ferricyanide and catechol. Electrodes were prepared by introducing proper amount of DWCNT and MWCNT into GCPE. First untreated materials (DWCNT, MWCNT, GC ?-particles) were used in the electrodes and then HNO3-treated materials were utilized for comparing difference in electrochemical performances. The effect of treatment procedure was also examined by applying Raman spectroscopy to treated and untreated materials. Moreover, TEM images were obtained for further investigation of MWCNT and DWCNT. PMID:20672081

2010-01-01

398

Analysis of the stable carbon isotope composition of formic and acetic acids.  

PubMed

Formic and acetic acids are ubiquitous in the environment and in many biological processes. Analysis of the stable carbon isotope composition (?(13)C) of formic and acetic acids is important to understanding their biogeochemical cycles. However, it has been faced with poor accuracy and high detection limits due to their low carbon number, high hydrophilicity, and semi-volatility. Here we developed an analytical technique by needle trap and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The organic acids in aqueous solution were extracted using a NeedlEx needle through purge-and-trap and were analyzed by GC-IRMS for ?(13)C. The procedures incur no isotope fractionation. Defined as the point at which the mean ?(13)C is statistically the same as the given value and the analytical error starts rising, the method's detection limits are 200 and 100 mg/L for formic and acetic acids, respectively, with an uncertainty of approximately 0.5‰ in direct extraction and analysis. They were lowered to 1 mg/L with precision of 0.9‰ after samples were subjected to preconcentration. The method was successfully applied to natural samples as diverse as precipitation, vinegars, ant plasma, and vehicle exhaust, which vary considerably in concentration and matrix of the organic acids. It is applicable to the organic acids in not only aqueous solution but also gaseous phase. PMID:23395975

Lee, Xinqing; Zhang, Like; Huang, Daikuan; An, Ning; Yang, Fang; Jiang, Wei; Fang, Bin

2013-05-15

399

Design and synthesis of palladium/graphitic carbon nitride/carbon black hybrids as high-performance catalysts for formic acid and methanol electrooxidation  

NASA Astrophysics Data System (ADS)

Here we report a facile two-step method to synthesize high-performance palladium/graphitic carbon nitride/carbon black (Pd/g-C3N4/carbon black) hybrids for electrooxidizing formic acid and methanol. The coating of g-C3N4 on carbon black surface is realized by a low-temperature heating treatment, followed by the uniform deposition of palladium nanoparticles (Pd NPs) via a wet chemistry route. Owning to the significant synergistic effects of the individual components, the preferred Pd/g-C3N4/carbon black electrocatalyst exhibits exceptional forward peak current densities as high as 2155 and 1720 mA mg-1Pd for formic acid oxidation in acid media and methanol oxidation in alkaline media, respectively, far outperforming the commercial Pd-C catalyst. The catalyst also shows reliable stability, demonstrating that the newly-designed hybrids have great promise in constructing high-performance portable fuel cell systems.

Qian, Huayu; Huang, Huajie; Wang, Xin

2015-02-01

400

Calcium carbonate breath test for non-invasive estimation of gastric acid secretion.  

PubMed

Gastric acid measurement is useful in assessing the effectiveness of antisecretory drugs, however, the conventional tests involve invasive nasogastric intubation. Orally administered ¹³C-labeled calcium carbonate (Ca¹³CO?) reacts with gastric acid to produce ¹³C-labeled carbon dioxide (¹³CO?), which is then excreted in the breath. The objective of this study was to evaluate the suitability of Ca¹³CO3 breath test for estimating gastric acid secretion in human noninvasively. First, the Ca¹³CO? breath test and the measurement of pooled gastric acid under a fasting condition were performed in 6 healthy volunteers to evaluate the correlation between the two parameters. Next, endoscopic gastric acid collection and the Ca¹³CO? breath test were performed on different days after pentagastrin injection in 20 subjects to evaluate the correlation between the tests and the reproducibility. Finally, the same studies were repeated in 4 subjects before and after 1-week rabeprazole, a proton pump inhibitor, administration. The maximum CO? concentration (Cmax) correlated very well with the amount of pooled gastric acid (r = 0.95), suggesting that Ca¹³CO? breath test values well reflected the fasting intragastric acidity. The ¹³CO? concentration after pentagastrin injection correlated well with pentagastrin-stimulated maximal acid output (r = 0.79 at 20 min). The reproducibility of the Ca¹³CO? breath test under pentagastrin-stimulation was good (coefficient of variation = 0.11). Rabeprazole administration markedly reduced the values of the Ca¹³CO? breath test, suggesting that it can sensitively assess the efficacy of rabeprazole. The Ca¹³CO? breath test can potentially be a useful method for non-invasive estimation for gastric acid secretion in human. PMID:24670370

Shinkai, Hirohiko; Iijima, Katsunori; Koike, Tomoyuki; Nakagawa, Kenichiro; Maejima, Ryuhei; Endo, Hiroyuki; Ara, Nobuyuki; Asano, Naoki; Imatani, Akira; Ohara, Shuichi; Shimosegawa, Tooru

2014-01-01

401

ESTERIFICATION OF OLEIC ACID IN SUPERCRITICAL CARBON DIOXIDE CATALYZED BY FUNCTIONALIZED MESOPOROUS SILICA AND AN IMMOBILIZED LIPASE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organosulfonic acid-functionalized mesoporous silicas were tested for catalytic performance in the esterification of oleic acid with methanol in flowing supercritical carbon dioxide. The energy of activation of the sulfonic acid catalysts was found to be about 42 kJ/mol and was shown to be independ...

402

Nomex polyaramid as a precursor for activated carbon fibres by phosphoric acid activation. Temperature and time effects  

Microsoft Academic Search

This work concerns the preparation of activated carbon fibres (ACFs) by phosphoric acid activation of Nomex [poly(m-phenylene isophthalamide)] polyaramid fibres. The transformations involved in Nomex pyrolysis in the presence of phosphoric acid as a function of temperature were studied by infrared spectroscopy. Then, ACFs were prepared by impregnating Nomex with phosphoric acid, followed by pyrolysis and washing with water. The

Fabián Suárez-García; Amelia Martínez-Alonso; Juan M. D. Tascón

2004-01-01

403

The adsorption of gold, palladium and platinum from acidic chloride solutions on mesoporous carbons.  

SciTech Connect

Studies on the adsorption characteristics of gold, palladium and platinum on mesoporous carbon (CMK-3) and sulfur-impregnated mesoporous carbon (CMK-3/S) evaluated the benefits/drawbacks of the presence of a layer of elemental sulfur inside mesoporous carbon structures. Adsorption isotherms collected for Au(III), Pd(II) and Pt(IV) on those materials suggest that sulfur does enhance the adsorption of those metal ions in mildly acidic environment (pH 3). The isotherms collected in 1 M HCl show that the benefit of sulfur disappears due to the competing influence of large concentration of hydrogen ions on the ion-exchanging mechanism of metal ions sorption on mesoporous carbon surfaces. The collected acid dependencies illustrate similar adsorption characteristics for CMK-3 and CMK-3/S in 1-5 M HCl concentration range. Sorption of metal ions from diluted aqueous acidic mixtures of actual leached electronic waste demonstrated the feasibility of recovery of gold from such liquors.

Peter Zalupski; Rocklan McDowell; Guy Dutech

2014-10-01

404

REACTIVE FLOW IN VUGGY CARBONATES: METHODS AND MODELS APPLIED TO MATRIX ACIDIZING OF CARBONATES  

E-print Network

dissolution of fossil fragments, or voids within or between fossils that were never filled in by sediment (Lucia, 1999). Carbonate rocks contain more than 50% of the world?s hydrocarbon reserves many of them exhibit complex geology such as the vuggy...

Izgec, Omer

2010-07-14

405

One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production  

SciTech Connect

This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. (CBS)

Zeikus, J.G.; Jain, M.K.

1992-01-01

406

Neutralizing Carbonic Acid in Deep Carbonate Strata below the North Atlantic  

SciTech Connect

Our research is aimed at investigating several technical issues associated with carbon dioxide sequestration in calcium carbonate sediments below the sea floor through laboratory experiments and chemical transport modeling. Our goal is to evaluate the basic feasibility of this approach, including an assessment of optimal depths, sediment types, and other issues related to site selection. The results of our modeling efforts were published this past summer in the Proceedings of the National Academy of Sciences. We are expanding on that work through a variety of laboratory and modeling efforts. In the laboratories at Columbia and at Harvard, we are studying the flow of liquid carbon dioxide and carbon dioxide-water mixtures through calcium carbonate sediments to better understand the geomechanical and structural stability of the sediments during and after injection. We are currently preparing the results of these findings for publication. In addition, we are investigating the kinetics of calcium carbonate dissolution in the presence of CO{sub 2}-water fluids, which is a critical feature of the system as it allows for increased permeability during injection. We are also investigating the possibility of carbon dioxide hydrate formation in the pore fluid, which might complicate the injection procedure by reducing sediment permeability but might also provide an upper seal in the sediment-pore fluid system, preventing release of CO{sub 2} into the deep ocean, particularly if depth and temperature at the injection point rule out immediate hydrate formation. This is done by injecting liquid CO{sub 2} into various types of porous media, and then monitoring the changes in permeability. Finally, we are performing an economic analysis to estimate costs of drilling and gas injection, site monitoring as well as the availability of potential disposal sites with particular emphasis on those sites that are within the 200-mile economic zone of the United States. We present some preliminary results from these analyses. A paper discussing the site selection based on data from the Ocean Drilling Program and Deep Sea Drilling Program is currently in preparation.

Daniel P. Schrag

2006-07-14

407

Preparation of iron oxide-impregnated spherical granular activated carbon-carbon composite and its photocatalytic removal of methylene blue in the presence of oxalic acid.  

PubMed

The spherical granular activated carbon-carbon composites (GAC-Fe) with different iron oxide contents (Fe mass% = 0.6-10) were prepared by a pore volume impregnation method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2-adsorption results confirm the presence of amorphous iron oxide, pyrolytic carbon, and graphitized globular carbon nanoparticles covered with amorphous carbon in the CAG-Fe. The rate of photodegradation of methylene blue (MB) in aqueous solution under UV light in the presence of oxalic acid correlates with porosity of the prepared materials. The total MB removal includes the combination of adsorption and photodegradation without the addition of H2O2. The results of total organic carbon (TOC) analysis reveal that the decolorization of MB in aqueous solution containing oxalic acid corresponds to the decomposition of organic compounds to CO2 and H2O. PMID:24679083

Kadirova, Zukhra C; Hojamberdiev, Mirabbos; Katsumata, Ken-Ichi; Isobe, Toshihiro; Matsushita, Nobuhiro; Nakajima, Akira; Sharipov, Khasan; Okada, Kiyoshi

2014-01-01

408

From the First Measurements of Atmospheric Carbon Dioxide During the IGY to the Global Annual Greenhouse Gas Index in 2006: The Evolution of the Global Observing Network for Greenhouse Gases.  

NASA Astrophysics Data System (ADS)

During the International Geophysical Year, Dr. Charles "Dave" Keeling instituted both air sample collections at the South Pole in Antarctica and continuous carbon dioxide measurements with an infrared analyzer at the Mauna Loa Observatory in Hawaii. Both of these locations were later to become Observatories of the U.S. National Oceanic and Atmospheric Administration (NOAA), following its formation in 1970, and the pioneering measurements of Dave Keeling continued to be supported by NOAA at these sites until this day. In addition to instituting Observatories at key background locations (Pt. Barrow, Alaska; American Samoa; and more recently Trinidad Head, California, in addition to the Hawaii and Antarctic sites) the forerunners of NOAA/ESRL also began a global cooperative air sampling network in the late 1960's. The air samples were analyzed for carbon dioxide and other gases in the Boulder, Colorado laboratories. With the help of many people in many nations, this network has grown to the largest such effort in the world, numbering about 90 sites, including three ship routes, at present. In 1996, data from this network and from other networks around the world formed the basis of GLOBALVIEW, a web-based collection of carbon dioxide and methane data used extensively with transport models to determine global carbon dioxide sources and sinks. This data set is available at http://www.cmdl.noaa.gov/ccgg/globalview/index.html . In 2004, the global measurements of all the long-lived greenhouse gases, including carbon dioxide, methane, nitrous oxide, the chlorofluorocarbons, and ten minor halogen gases were condensed into a simple index, the "Annual Greenhouse Gas Index" (AGGI) by summing their radiative climate forcing since the pre-industrial era (taken as 1750). The NOAA AGGI is designed to enhance the connection between scientists and society by providing a normalized standard that can be easily understood and followed. The contribution of long-lived greenhouse gases to climate forcing is well understood by scientists and has been reported through a range of national and international assessments. Nevertheless, the language of scientists (for example, watts per square meter per year) often eludes policy makers, educators, and the general public. This index is designed to help bridge that gap.

Hofmann, D. J.; Butler, J. H.; Dlugokencky, E. J.; Elkins, J. W.; Masarie, K.; Montzka, S. A.; Tans, P. P.

2006-05-01

409

In vitro toxicological characterization of perfluorinated carboxylic acids with different carbon chain lengths.  

PubMed

Perfluorooctanoic acid (PFOA) is in use for the production of fluoropolymers (PFT). Due to its toxic properties it was proposed to replace the substance in its industrial applications by homologous compounds with shorter carbon chain length that were supposed to be less toxic compared to PFOA, however, the smaller PFOA homologs are poorly characterized so far. In this study we have conducted a comparative analysis of the toxicity of perfluorinated carboxylic acids (PFCA) with a carbon chain length ranging from four to twelve carbon atoms. By using the human hepatocarcinoma cell line HepG2 as an in vitro model for human hepatocytes we could show a positive correlation between the carbon chain length of the respective PFCA and its cytotoxicity. There was, however, no indication of an apoptotic mechanism for cytotoxicity. All PFCA under investigation were negative in two independent genotoxicity assays. As PFOA, being a well-known peroxisome proliferator, the other PFCA tested in this study were also shown to activate human peroxisome proliferator-activated receptor alpha (PPAR?) with PFOA having the highest potential of PPAR? activation. Moreover, the compounds showed weak potential to activate PPAR? and hardly activated PPAR?. Taken together, the in vitro study revealed that PFCA with a shorter carbon chain length seem to be less toxic than PFOA. PMID:23391484

Buhrke, Thorsten; Kibellus, Anja; Lampen, Alfonso

2013-04-12

410

Competition between humic acid and carbonates for rare earth elements complexation.  

PubMed

The competitive binding of rare earth elements (REE) to humic acid (HA) and carbonates was studied experimentally at various pH and alkalinity values by combining ultrafiltration and inductively coupled plasma mass spectrometry techniques. The results show that the REE species occur as binary humate or carbonate complexes but not as ternary REE-carbonate-humate as previously proposed. The results also reveal the strong pH and alkalinity dependence of the competition as well as the existence of a systematic fractionation across the REE series. Specifically, carbonate complexation is at a maximum at pH 10 and increase with increasing alkalinity and with the atomic number of the REE (LuCO(3)>LaCO(3)). Modeling of the data using Model VI and recently published stability constants for complexation of REE by humic acid well reproduced the experimental data, confirming the ability of Model VI to accurately determine REE speciation in natural waters. This modeling also confirms the reliability of recently published stability constants. This work shed more light not only on the competition between carbonates and HA for REE complexation but also on the reliability of WHAM 6 and Model VI for calculating the speciation of REE with organic matter in alkaline organic-rich water. PMID:17052726

Pourret, Olivier; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

2007-01-01

411

Trade-off in emissions of acid gas pollutants and of carbon dioxide in fossil fuel power plants with carbon capture  

Microsoft Academic Search

This paper investigates the impact of capture of carbon dioxide (CO2) from fossil fuel power plants on the emissions of nitrogen oxides (NOX) and sulphur oxides (SOX), which are acid gas pollutants. This was done by estimating the emissions of these chemical compounds from natural gas combined cycle and pulverized coal plants, equipped with post-combustion carbon capture technology for the

Evangelos Tzimas; Arnaud Mercier; Calin-Cristian Cormos; Stathis D. Peteves

2007-01-01

412

Enhancing thermal conductivity of palmitic acid based phase change materials with carbon nanotubes as fillers  

SciTech Connect

Multi-walled carbon nanotubes (CNTs) as produced are usually entangled and not ready to be dispersed into organic matrix. CNTs were treated by mechano-chemical reaction with ball milling the mixture of potassium hydroxide and the pristine CNTs. Hydroxide radical functional groups have been introduced on the CNT surfaces, which enabled to make stable and homogeneous CNT composites. Treated CNTs were successfully dispersed into the palmitic acid matrix without any surfactant. Transient short-hot-wire apparatus was used to measure the thermal conductivities of these nanotube composites. Nanotube composites have substantially higher thermal conductivities than the base palmitic acid matrix, with the enhancement increasing with the mass fraction of CNTs in both liquid state and solid state. The enhancements of the thermal conductivity are about 30% higher than the reported corresponding values for palmitic acid based phase change nanocomposites containing 1 wt% CNTs treated by concentrated acid mixture. (author)

Wang, Jifen [School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209 (China); State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xie, Huaqing; Li, Yang; Chen, Lifei [School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209 (China); Xin, Zhong [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2010-02-15

413

Selective Acidic Leaching of Spent Zinc-Carbon Batteries Followed by Zinc Electrowinning  

NASA Astrophysics Data System (ADS)

In this work, a selective acidic leaching procedure was employed for recycling zinc from spent zinc-carbon batteries. Leaching experiments were carried out in order to maximize zinc recovery and minimize manganese recovery in diluted sulfuric acid media. Response surface methodology and analysis of variance were employed for experimental design, data analysis, and leaching optimization. The experimental design has 28 experiments that include 24 main runs and four replicate in center point. The optimal conditions obtained from the selective acidic leaching experiments, were sulfuric acid concentration of 1 pct v/v, leaching temperature of 343 K (70 °C), pulp density of 8 pct w/v, and stirring speed of 300 rpm. The results show that the zinc and manganese recoveries after staged selective leaching are about 92 and 15 pct, respectively. Finally, metallic zinc with purity of 99.9 pct and electrolytic manganese dioxide were obtained by electrowinning.

Shalchian, Hossein; Rafsanjani-Abbasi, Ali; Vahdati-Khaki, Jalil; Babakhani, Abolfazl

2015-02-01

414

The influence of some Arylazobenzoyl acetonitrile derivatives on the behaviour of carbon steel in acidic media  

NASA Astrophysics Data System (ADS)

The effect of a new class of corrosion inhibitors, namely, Arylazobenzoyl acetonitrile derivatives, on the corrosion of carbon steel in 2 M HCl and 1 M H 2SO 4 solutions has been studied by electrochemical polarisation methods (potentiodynamic, Tafel extrapolation and the determination of polarisation resistance). Generally, inhibition efficiency of the investigated compounds was found to increases with increasing concentration. Results obtained from both potentiodynamic and polarisation resistance techniques reveal that these compounds are good inhibitors and behave better in 2 M HCl than 1 M H 2SO 4. The adsorption of the compounds on the carbon steel in both acidic media follows a Langmuir adsorption isotherm.

Abd El-Maksoud, S. A.

2003-02-01

415

Microwave-assisted polyol synthesis of carbon nitride dots from folic acid for cell imaging  

PubMed Central

A green, one-step microwave-assisted polyol synthesis was employed to prepare blue luminescent carbon nitride dots (CNDs) using folic acid molecules as both carbon and nitrogen sources. The as-prepared CNDs had an average size of around 4.51 nm and could be well dispersed in water. Under excitation at 360 nm, the CNDs exhibited a strong blue luminescence and the quantum yield was estimated to be 18.9%, which is greater than that of other reported CNDs. Moreover, the CNDs showed low cytotoxicity and could efficiently label C6 glioma cells, demonstrating their potential in cell imaging. PMID:25382977

Guan, Weiwei; Gu, Wei; Ye, Ling; Guo, Chenyang; Su, Su; Xu, Pinxiang; Xue, Ming

2014-01-01

416

Extraction of palladium from acidic solutions with the use of carbon adsorbents  

SciTech Connect

We studied the sorption of palladium(II) on LKAU-4, LKAU-7, and BAU carbon adsorbents from model hydrochloric acid solutions and the solutions of spent palladium-containing catalysts. It was found that sorbents based on charcoal (BAU) and anthracite (LKAU-4) were characterized by high sorption capacities for palladium. The kinetics of the saturation of carbon adsorbents with palladium(II) ions was studied, and it was found that more than 60% of the initial amount of Pd(II) was recovered in a 1-h contact of an adsorbent with a model solution. This value for the solutions of spent catalysts was higher than 35%.

O.N. Kononova; N.G. Goryaeva; N.B. Dostovalova; S.V. Kachin; A.G. Kholmogorov [Krasnoyarsk State University, Krasnoyarsk (Russian Federation)

2007-08-15

417

Abating environmentally harmful waste gases  

NASA Astrophysics Data System (ADS)

A gas-purification method, based on the condensation of nitrogen, sulfur, and carbon-containing environmentally hazardous gases produced from industrial processes, is proposed in this article. The method, which utilizes the cooling capacity of waste nitrogen in the oxygen plant to condense the hazardous gases, is capable of removing hazardous impurities up to 99.98%. Theoretical calculations underlying the condensation process are presented employing gases produced in a blast furnace and coke oven in an integrated steel plant. The cooling power required for the condensation process is calculated using the waste nitrogen generated from an oxygen plant that generates captive oxygen for the steel plant. Design modifications that need to be made to the oxygen plant in order to utilize the cooling power of the waste nitrogen gas are also presented. As a case study, the advantages of the method are illustrated with purification of coke-oven gas. The economic impact and the investment aspects are also discussed.

Sridhar, S.; Sichen, Du; Pal, U. B.; Seetharaman, S.

2002-05-01

418

Fatty acid and stable carbon isotope characterization of Camelina sativa oil: implications for authentication.  

PubMed

The importance of authenticity characterization is an increasing and pressing requirement for all foods. Vegetable oil is one of the most studied foods because of its nutritional and medicinal properties in a correct diet. In this study, a total of 53 Camelina sativa samples, from all known growing areas, were chemically and isotopically characterized. The fatty acid content of camelina oil was determined by gas chromatography (GC), and the ratios of stable carbon isotopes ((13)C/(12)C) of individual fatty acids and seed/bulk oil were determined by gas chromatography-combustion-stable isotope ratio mass spectrometry (GC/C/IRMS) and elemental analysis-stable isotope ratio mass spectrometry (IRMS). A total of 17 different fatty acids were detected by GC, with omega3 R-linolenic acid (C(18:3n3)) being the most abundant (29.7-40.0 wt %). Oleic acid (C(18:1n9)), linoleic acid (C(18:2n6)) and eicosenoic acid (C(20:1n9)) all belong to the second group of major fatty acids. The stable carbon isotopic values (delta(13)C) fell into a range typical for C(3) plants. The use of delta(13)C(18:2n6) vs delta(13)C(18:3n3) correlation could show cases where impurity or adulteration is suspected, whereas principal component analysis clearly separates oil samples from different continents. Preliminary results on the camelina oil authentication procedure provide a basis for the investigation of geographical origin and the further distinction between camelina and camelina refined or other, less expensive oils. PMID:19123821

Hrastar, Robert; Petrisic, Marinka G; Ogrinc, Nives; Kosir, Iztok Joze

2009-01-28

419

Optimization of modified carbon paste electrode with multiwalled carbon nanotube/ionic liquid/cauliflower-like gold nanostructures for simultaneous determination of ascorbic acid, dopamine and uric acid.  

PubMed

We describe the modification of a carbon paste electrode (CPE) with multiwalled carbon nanotubes (MWCNTs) and an ionic liquid (IL). Electrochemical studies by using a D-optimal mixture design in Design-Expert software revealed an optimized composition of 60% graphite, 14.2% paraffin, 10.8% MWCNT and 15% IL. The optimal modified CPE shows good electrochemical properties that are well matched with model prediction parameters. In the next step, the optimized CPE was modified with gold nanostructures by applying a double-pulse electrochemical technique. The resulting electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. It gives three sharp and well-separated oxidation peaks for ascorbic acid (AA), dopamine (DA), and uric acid (UA). The sensor enables simultaneous determination of AA, DA and UA with linear responses from 0.3 to 285, 0.08 to 200, and 0.1 to 450 ?M, respectively, and with 120, 30 and 30 nM detection limits (at an S/N of 3). The method was successfully applied to the determination of AA, DA, and UA in spiked samples of human serum and urine. PMID:25280680

Afraz, Ahmadreza; Rafati, Amir Abbas; Najafi, Mojgan

2014-11-01

420

Characterization of nano-lead-doped active carbon and its application in lead-acid battery  

NASA Astrophysics Data System (ADS)

In this paper, nano-lead-doped active carbon (nano-Pb/AC) composite with low hydrogen evolution current for lead-acid battery was prepared by ultrasonic-absorption and chemical-precipitate method. The nano-Pb/AC composite was characterized by SEM, EDS and TEM. The electrochemical characterizations are performed by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in a three-electrode system. Since intermediate adsorption is the rate-determining step, the hydrogen evolution reaction (HER) is markedly inhibited as the intermediate adsorption impedance of nano-Pb/AC increased. Meanwhile, the working potential of nano-Pb/AC is widened to the whole potential region of Pb negative plate (from -1.36 V to -0.86 V vs. Hg/HgSO4) in lead-acid battery. In addition, nano-Pb can improve the interfacial compatibility between AC and Pb paste, accordingly relieve the symptoms of carbon floatation. Finally, 2.0 V single-cell flooded lead-acid batteries with 1.0 wt.% nano-Pb/AC or 1.0 wt.% AC addition in negative active materials are assembled. The cell performances test results show that the 3 h rate capacity, quick charging performance, high current discharging performance and cycling performance of nano-Pb/AC modified battery are all improved compared with regular lead-acid battery and AC modified lead-acid battery.

Hong, Bo; Jiang, Liangxing; Xue, Haitao; Liu, Fangyang; Jia, Ming; Li, Jie; Liu, Yexiang

2014-12-01

421

Surface and catalytic properties of acid metal carbons prepared by the sol gel method  

NASA Astrophysics Data System (ADS)

The sol-gel method has been applied for the synthesis of a series of acid metal-carbon xerogels (with M = V, Cr, Mo and Ni) by polymerisation of resorcinol with formaldehyde in the presence of metallic precursors. A blank sample was also prepared without any metal addition. The xerogels were heated in nitrogen at 1000 °C to obtain the pyrolysed products. The samples were characterised by different techniques such as thermal-mass spectrometry analysis, gas physisorption, and mercury porosimetry. In addition, the acid character of the pyrolysed products was tested by the Claisen-Schmidt condensation between benzaldehyde and acetophenone for the formation of chalcones.

Aguado-Serrano, J.; Rojas-Cervantes, M. L.; Martín-Aranda, R. M.; López-Peinado, A. J.; Gómez-Serrano, V.

2006-06-01

422

Scalable, Non-Invasive Glucose Sensor Based on Boronic Acid Functionalized Carbon Nanotube Transistors  

E-print Network

We developed a scalable, label-free all-electronic sensor for D-glucose based on a carbon nanotube transistor functionalized with pyrene-1-boronic acid. This sensor responds to glucose in the range 1 uM - 100 mM, which includes typical glucose concentrations in human blood and saliva. Control experiments establish that functionalization with the boronic acid provides high sensitivity and selectivity for glucose. The devices show better sensitivity than commercial blood glucose meters and could represent a general strategy to bloodless glucose monitoring by detecting low concentrations of glucose in saliva.

Lerner, Mitchell B; Mendoza, Ryan; Villechenon, Romain; Lopez, Manuel A Bonilla; Johnson, A T Charlie

2013-01-01

423

Scalable, non-invasive glucose sensor based on boronic acid functionalized carbon nanotube transistors  

NASA Astrophysics Data System (ADS)

We developed a scalable, label-free all-electronic sensor for D-glucose based on a carbon nanotube transistor functionalized with pyrene-1-boronic acid. This sensor responds to glucose in the range 1 ?M-100 mM, which includes typical glucose concentrations in human blood and saliva. Control experiments establish that functionalization with the boronic acid provides high sensitivity and selectivity for glucose. The devices show better sensitivity than commercial blood glucose meters and could represent a general strategy to bloodless glucose monitoring by detecting low concentrations of glucose in saliva.

Lerner, Mitchell B.; Kybert, Nicholas; Mendoza, Ryan; Villechenon, Romain; Bonilla Lopez, Manuel A.; Charlie Johnson, A. T.

2013-05-01

424

Carbon quantum dots with photo-generated proton property as efficient visible light controlled acid catalyst  

NASA Astrophysics Data System (ADS)

Developing light-driven acid catalyst will be very meaningful for the controlled-acid catalytic processes towards a green chemical industry. Here, based on scanning electrochemical microscopy (SECM) and ?pH testing, we demonstrate that the 5-10 nm carbon quantum dots (CQDs) synthesized by electrochemical ablation of graphite have strong light-induced proton properties under visible light in solution, which can be used as an acid catalyst. The 5-10 nm CQDs' catalytic activity is strongly dependent on the illumination intensity and the temperature of the reaction system. As an effective visible light driven and controlled acid-catalyst, 5-10 nm CQDs can catalyze a series of organic reactions (esterification, Beckmann rearrangement and aldol condensation) with high conversion (34.7-46.2%, respectively) in water solution under visible light, while the 1-4 nm CQDs and 10-2000 nm graphite do not have such excellent catalytic activity. The use of 5-10 nm CQDs as a light responsive and controllable photocatalyst is truly a novel application of carbon-based nanomaterials, which may significantly push research in the current catalytic industry, environmental pollution and energy issues.Developing light-driven acid catalyst will be very meaningful for the controlled-acid catalytic processes towards a green chemical industry. Here, based on scanning electrochemical microscopy (SECM) and ?pH testing, we demonstrate that the 5-10 nm carbon quantum dots (CQDs) synthesized by electrochemical ablation of graphite have strong light-induced proton properties under visible light in solution, which can be used as an acid catalyst. The 5-10 nm CQDs' catalytic activity is strongly dependent on the illumination intensity and the temperature of the reaction system. As an effective visible light driven and controlled acid-catalyst, 5-10 nm CQDs can catalyze a series of organic reactions (esterification, Beckmann rearrangement and aldol condensation) with high conversion (34.7-46.2%, respectively) in water solution under visible light, while the 1-4 nm CQDs and 10-2000 nm graphite do not have such excellent catalytic activity. The use of 5-10 nm CQDs as a light responsive and controllable photocatalyst is truly a novel application of carbon-based nanomaterials, which may significantly push research in the current catalytic industry, environmental pollution and energy issues. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03996j

Li, Haitao; Liu, Ruihua; Kong, Weiqian; Liu, Juan; Liu, Yang; Zhou, Lei; Zhang, Xing; Lee, Shuit-Tong; Kang, Zhenhui

2013-12-01

425

Isotopic composition of Murchison organic compounds: Intramolecular carbon isotope fractionation of acetic acid. Simulation studies of cosmochemical organic syntheses  

NASA Technical Reports Server (NTRS)

Recently, in our laboratories, samples of Murchison acetic acid were decarboxylated successfully and the carbon isotopic composition was measured for the methane released by this procedure. These analyses showed significant differences in C-13/C-12 ratios for the methyl and carboxyl carbons of the acetic acid molecule, strongly suggesting that more than one carbon source may be involved in the synthesis of the Murchison organic compounds. On the basis of this finding, laboratory model systems simulating cosmochemical synthesis are being studied, especially those processes capable of involving two or more starting carbon sources.

Yuen, G. U.; Cronin, J. R.; Blair, N. E.; Desmarais, D. J.; Chang, S.

1991-01-01

426

Effects of Acid Additives on Spent Acid Flowback through Carbonate Cores  

E-print Network

Io Intensity of the emitted x-ray beam I Intensity of the detected x-ray beam H Thickness of the object being scanned PPE Personal Protective Equipment MSDS Material Safety Data Sheet PVC Polyvinyl chloride exp. Experiment FA-CI Formic Acid...-ICA ........................................................................ 19 xi FIGURE Page 3.16 Iron control agent T...

Nasir, Ehsaan Ahmad

2012-07-16

427

Investigating the Effect of Oil Saturation on Acid Propagation during Matrix Acidization of Carbonate Rocks  

E-print Network

and dolomite reservoir cores, and low permeability Indiana limestone cores of dimensions 3 and 6 in. length and 1.5 in. diameter. Absolute permeability of the cores ranged from 1 to 78 md. The study involved acidizing cores saturated with water, oil...

Kumar, Rahul Pradeep

2014-01-02

428

Acid Diversion in Carbonate Reservoirs Using Polymer-Based In-Situ Gelled Acids  

E-print Network

and the acid injection rate should be determined based on the expected shear rate in the formation. A core flood experiment is recommended to confirm optimum injected rate. Well flow back is needed to minimize the residual gel inside the formation. The data...

Gomaa, Ahmed Mohamed Mohamed

2012-07-16

429

AIR INFILTRATION MEASUREMENTS USING TRACER GASES: A LITERATURE REVIEW  

EPA Science Inventory

The report gives results of a literature review of air filtration measurements using tracer gases, including sulfur hexafluoride, hydrogen, carbon monoxide, carbon dioxide, nitrous oxide, and radioactive argon and krypton. Sulfur hexafluoride is the commonest tracer gas of choice...

430

Carbon and hydrogen isotopic evidence for the origin of combustible gases in water-supply wells in north-central Pennsylvania  

USGS Publications Warehouse

The origin of the combustible gases in groundwater from glacial-outwash and fractured-bedrock aquifers was investigated in northern Tioga County, Pennsylvania. Thermogenic methane (CH4) and ethane (C2H6) and microbial CH4 were found. Microbial CH4 is from natural in situ processes in the shale bedrock and occurs chiefly in the bedrock aquifer. The ?13C values of CH4 and C2H6 for the majority of thermogenic gases from water wells either matched or were between values for the samples of non-native storage-field gas from injection wells and the samples of gas from storage-field observation wells. Traces of C2H6 with microbial CH4 and a range of C and H isotopic compositions of CH4 indicate gases of different origins are mixing in sub-surface pathways; gas mixtures are present in groundwater. Pathways for gas migration and a specific source of the gases were not identified. Processes responsible for the presence of microbial gases in groundwater could be elucidated with further geochemical study.

Révész, K. M.; Breen, K.J.; Baldassare, A.J.; Burruss, R.C.

2010-01-01

431

Modulation of acetone-butanol-ethanol fermentation by carbon monoxide and organic acids  

SciTech Connect

Metabolic modulation of acetone-butanol-ethanol fermentation by Clostridium acetobutylicum with carbon monoxide (CO) and organic acids is described. CO, which is a known inhibitor of hydrogenase, was found to be effective in the concentration range of dissolved CO corresponding to a CO partial pressure of 0.1 to 0.2 atm. Metabolic modulation by CO was particularly effective when organic acids such as acetic and butyric acids were added to the fermentation as electron sinks. The uptake of organic acids was enhanced, and increases in butyric acid uptake by 50 to 200% over control were observed. Hydrogen production could be reduced by 50% and the ratio of solvents could be controlled by CO modulation and organic acid addition. Acetone production could be eliminated if desired. Butanol yield could be increased by 10 to 15%. Total solvent yield could be increased 1 to 3% and the electron efficiency to acetone-butanol-ethanol solvents could be increased from 73 to 78% for controls to 80 to 85% for CO- and organic acid-modulated fermentations. Based on these results, the dynamic nature of electron flow in this fermentation has been elucidated and mechanisms for metabolic control have been hypothesized.

Datta, R.; Zeikus, J.G.

1985-03-01

432

Carbon honeycomb grids for advanced lead-acid batteries. Part I: Proof of concept  

NASA Astrophysics Data System (ADS)

The carbon honeycomb grid is proposed as innovative solution for high energy density lead acid battery. The proof of concept is demonstrated, developing grids suitable for the small capacity, scale of valve-regulated lead acid batteries with 2.5-3 Ah plates. The manufacturing of the grids, includes fast, known and simple processes which can be rescaled for mass production with a minimum, investment costs. The most critical process of green composite carbonisation by heating in inert, atmosphere from 200 to 1000 °C takes about 5 h, guaranteeing the low cost of the grids. An AGM-VRLA, cell with prototype positive plate based on the lead-2% tin electroplated carbon honeycomb grid and, conventional negative plates is cycled demonstrating 191 deep cycles. The impedance spectroscopy, measurements indicate the grid performance remains acceptable despite the evolution of the corrosion, processes during the cycling.

Kirchev, Angel; Kircheva, Nina; Perrin, Marion

2011-10-01

433

Simultaneous adsorption of copper ions and humic acid onto an activated carbon.  

PubMed

In this study, simultaneous adsorption of copper ions and humic acid (HA) from Aldrich onto an activated carbon is investigated. It is found that the HA adsorption in the absence of copper decreases as the pH is increased. It leads to a reduction of 34.7% in the specific surface area of carbon. There exists a critical concentration (CC) of HA for copper adsorption. At HA concentrations < CC, a decrease in copper adsorption is observed; however, the HA improves the adsorption at HA concentrations > CC. An increase in ionic strength can enhance the copper uptake; however, zinc and/or cobalt ions have an insignificant influence on copper adsorption. The adsorption is significantly increased by citric acid, whereas addition of EDTA slightly decreases the uptake. An intraparticle diffusion model is successfully used to describe the copper adsorption kinetics. PMID:15533405

Chen, J Paul; Wu, Shunnian

2004-12-15

434

Formaldehyde removal by Rayon-based activated carbon fibers modified by P -aminobenzoic acid  

Microsoft Academic Search

We impregnated Rayon-based activated carbon fibers (ACFs) by p-aminobenzoic acid (PABA) and systematically investigated their porous structure, surface chemistry, and formaldehyde removal\\u000a behavior. Using standard nitrogen adsorption analysis, we found that the specific surface area, the micropore volume, and\\u000a the total pore volume decreased with increasing concentration of PABA. Through elemental analysis and X-ray photoelectron\\u000a spectroscopy, it was found that

Haiqin Rong; Zhenyu Liu; Qilin Wu; Ding Pan; Jingtang Zheng

2010-01-01

435

Antimicrobial biomaterials based on carbon nanotubes dispersed in poly(lactic-co-glycolic acid)  

Microsoft Academic Search

Biomaterials that inactivate microbes are needed to eliminate medical device infections. We investigate here the antimicrobial nature of single-walled carbon nanotubes (SWNTs) incorporated within the biomedical polymer poly(lactic-co-glycolic acid) (PLGA). We find Escherichia coli and Staphylococcus epidermidis viability and metabolic activity to be significantly diminished in the presence of SWNT-PLGA, and to correlate with SWNT length and concentration (<2% by

Seyma Aslan; Codruta Zoican Loebick; Seoktae Kang; Menachem Elimelech; Lisa D. Pfefferle; Paul R. van Tassel

2010-01-01

436

Poly(lactic–co-glycolic acid): Carbon nanofiber composites for myocardial tissue engineering applications  

Microsoft Academic Search

The objective of the present in vitro research was to investigate cardiac tissue cell functions (specifically cardiomyocytes and neurons) on poly(lactic–co-glycolic acid) (PLGA) (50:50wt.%)–carbon nanofiber (CNF) composites to ascertain their potential for myocardial tissue engineering applications. CNF were added to biodegradable PLGA to increase the conductivity and cytocompatibility of pure PLGA. For this reason, different PLGA:CNF ratios (100:0, 75:25, 50:50,

David A. Stout; Bikramjit Basu; Thomas J. Webster

2011-01-01

437

The erosion of carbonate stone by acid rain: Laboratory and field investigations  

USGS Publications Warehouse

One of the goals of research on the effects of acidic deposition on carbonate stone surfaces is to define the incremental impact of acidic deposition relative to natural weathering processes on the rate of carbonate stone erosion. If rain that impacts carbonate stone surfaces is resident on the surface long enough to approach chemical equilibrium, the incremental effect of hydrogen ion is expected to be small (i.e., 6% for a rain of pH 4.0). Under nonequilibrium (i.e., high flow rate) conditions, kinetic considerations suggest that the incremental effect of hydrogen ion deposition could be quite significant. Field run-off experiments involving the chemical analysis of rain collected from inclined stone slabs have been used to evaluate stone dissolution processes under ambient conditions of wet and dry deposition of acidic species. The stoichiometry of the reaction of stone with hydrogen ion is difficult to define from the field data due to scatter in the data attributed to hydrodynamic effects. Laboratory run-off experiments show that the stoichiometry is best defined by a reaction with H+ in which CO2 is released from the system. The baseline effect caused by water in equilibrium with atmospheric CO2 is identical in the field and in laboratory simulation. The experiments show that the solutions are close enough to equilibrium for the incremental effect of hydrogen ion to be minor (i.e., 24% for marble for a rain of pH 4.0) relative to dissolution due to water and carbonic acid reactions. Stone erosion rates based on physical measurement are approximately double the recession rates that are due to dissolution (estimated from the observed calcium content of the run-off solutions). The difference may reflect the loss of granular material not included in recession estimates based on the run-off data. Neither the field nor the laboratory run-off experiments indicate a pH dependence for the grain-removal process.

Baedecker, P.A.; Reddy, M.M.

1993-01-01

438

Efficient Synthesis of ?-Monoglycerides via Solventless Condensation of Fatty Acids with Glycerol Carbonate  

Microsoft Academic Search

Highly pure ?-monoglycerides (5a–e) were successfully prepared in high yields by the condensation of fatty acids such as lauric,\\u000a myristic, palmitic, stearic and oleic (2a–e) with glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) (1) in the presence\\u000a of triethylamine as catalyst. Reaction conditions and spectroscopic identification of products will be presented in this article.

Mehdi Ghandi; Abdoljalil Mostashari; Mojgan Karegar; Mina Barzegar

2007-01-01

439

Preparation of ?-Ca 3(PO 4) 2 bioceramic powder from calcium carbonate and phosphoric acid  

Microsoft Academic Search

When preparing ?-tricalcium phosphate (?-TCP) with Ca(NO3)2 or Ca(OH)2 as the raw materials, because of the problem of filtering, it is difficult to industrialize traditional methods. In this paper, ?-TCP was prepared with calcium carbonate and phosphoric acid. According to XRD spectrum, the precursor of this system is octacalcium phosphate (OCP) [Ca8H2(PO4)6·5H2O] instead of non-stoichiometric hydroxyapatite (HA) obtained from traditional

Yun Zhang; Guangfu Yin; Shifu Zhu; Dali Zhou; Yuehua Wang; Yong Li; Lin Luo

2005-01-01

440

Preparation of poly(lactic acid)\\/siloxane\\/calcium carbonate composite membranes with antibacterial activity  

Microsoft Academic Search

A poly(lactic acid) (PLA)\\/siloxane\\/calcium carbonate composite membrane containing mercapto groups (PSC-SH) with antibacterial ability and excellent bone-forming ability was prepared using 3-mercaptopropyltrimethoxysilane for application in guided bone regeneration. Mercapto groups were reported to adsorb silver ions, which are well known to show antibacterial activity. Ionic silicon species were reported to stimulate the proliferation of osteoblasts. A PSC-SH membrane with a

Shingo Tokuda; Akiko Obata; Toshihiro Kasuga

2009-01-01

441

Heterogeneous reactions of gaseous methanesulfonic acid with calcium carbonate and kaolinite particles  

Microsoft Academic Search

Heterogeneous reactions of gaseous methanesulfonic acid (MSA) with calcium carbonate (CaCO3) and kaolinite particles at room temperature were investigated using diffuse reflectance infrared Fourier transform spectroscopy\\u000a (DRIFTS) and ion chromatography (IC). Methanesulfonate (MS?) was identified as the product in the condensed phase, in accordance with the product of the reaction of gaseous MSA with\\u000a NaCl and sea salt particles. When

MingJin Tang; MengQiu Li; Tong Zhu

2010-01-01

442

Free nitrous acid pretreatment of wasted activated sludge to exploit internal carbon source for enhanced denitrification.  

PubMed

Using internal carbon source contained in waste activated sludge (WAS) is beneficial for nitrogen removal from wastewater with low carbon/nitrogen ratio, but it is usually limited by sludge disintegration. This study presented a novel strategy based on free nitrous acid (FNA) pretreatment to intensify the release of organic matters from WAS for enhanced denitrification. During FNA pretreatment, soluble chemical oxygen demand (SCOD) production kept increasing when FNA increased from 0 to 2.04mg HNO2-N/L. Compared with untreated WAS, the internal carbon source production increased by 50% in a simultaneous fermentation and denitrification reactor fed with WAS pretreated by FNA for 24h at 2.04mg HNO2-N/L. This also increased denitrification efficiency by 76% and sludge reduction by 87.5%. More importantly, greenhouse gas nitrous oxide production in denitrification was alleviated since more electrons could be provided by FNA pretreated WAS. PMID:25514398

Ma, Bin; Peng, Yongzhen; Wei, Yan; Li, Baikun; Bao, Peng; Wang, Yayi

2015-03-01

443

Inertisation of galvanic sludge with calcium oxide, activated carbon, and phosphoric acid.  

PubMed

In this study we compared three methods for the treatment of electroplating sludge highly loaded with zinc and iron: (1) calcium oxide-based solidification/stabilisation; (2) conversion into inert material by adsorption of organic and inorganic pollutants onto activated carbon; and (3) conversion of mobile waste components into insoluble phosphates. All three methods proved highly efficient in the conversion of hazardous waste into inert material. Under optimum treatment conditions zinc concentration in the leachate of solidified waste was reduced by 99.7 % compared to untreated sludge. Zinc retention efficiency in the waste treated with activated carbon and phosphoric acid was 99.9 % and 98.7 %, respectively. The advantages of electroplating sludge treatment with activated carbon over the other two methods are high sorption capacity, insignificant pH and volume changes of the sludge, and simple use. PMID:23152383

Oreš?anin, Višnja; Lovren?i? Mikeli?, Ivanka; Kollar, Robert; Mikuli?, Nenad; Meduni?, Gordana

2012-09-01

444

Electrochemical and XPS studies of decylamides of ?-amino acids adsorption on carbon steel in acidic environment  

NASA Astrophysics Data System (ADS)

Corrosion inhibition of steel in hydrochloric acid by decylamides of ?-amino acids derivatives was studied using gravimetric and electrochemical techniques. Protection efficiencies of 90% were obtained with 100 ppm of tyrosine and glycine derivatives, while alanine and valine derivatives reached only 80%. The order of increasing inhibition efficiency was correlated with the modification of the molecular structure of inhibitors. Potentiodynamic polarization curves indicated that both the decylamide of tyrosine and glycine acted primarily as anodic type inhibitors, whereas the decylamide of alanine and valine were of the cathodic type. Thermodynamic parameters and Flory-Huggins adsorption isotherms described the experimental findings. The number of active sites, equilibrium constant, enthalpy and change of free energy were computed for all inhibitors studied. This information suggested that organic molecules were adsorbed and displaced water molecules from the steel surface. X-ray photoelectron spectroscopy confirmed that species of N, C and O interacted with steel to form a continuous protective film.

Olivares, O.; Likhanova, N. V.; Gómez, B.; Navarrete, J.; Llanos-Serrano, M. E.; Arce, E.; Hallen, J. M.

2006-02-01

445

Tracing Carbon Sources through Aquatic and Terrestrial Food Webs Using Amino Acid Stable Isotope Fingerprinting  

PubMed Central

Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring ?13C patterns among amino acids (?13CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that ?13CAA patterns in contrast to bulk ?13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their ?13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk ?13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer ?13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. PMID:24069196

Larsen, Thomas; Ventura, Marc; Andersen, Nils; O’Brien, Diane M.; Piatkowski, Uwe; McCarthy, Matthew D.

2013-01-01

446

Extreme carbon dioxide concentrations in acidic pit lakes provoked by water/rock interaction.  

PubMed

We quantify the gas pressure and concentration of a gas-charged acidic pit lake in SW Spain. We measured total dissolved gas pressure, carbon dioxide (CO2) concentration, major ion concentration, isotopic composition of dissolved inorganic carbon (?(13)C(DIC)), and other physicochemical parameters. CO2 is the dominant dissolved gas in this lake and results mainly from carbonate dissolution during the interaction of acidic water with wall rocks, followed by diffusive and advective transport through the water column. The ?(13)C(DIC) values suggest that the biological contribution is comparatively small. Maximum CO2 concentrations higher than 0.1 M (?5000 mg/L) have been measured, which are only comparable to those found in volcanic crater lakes. The corresponding gas pressures of CO2 alone (pCO2 ?3.6 bar) imply 60% saturation relative to local pressure at 50 m depth. High CO2 concentrations have been observed in other pit lakes of the region. We recommend gas-specific monitoring in acidic pit lakes and, if necessary, the design of feasible degassing strategies. PMID:24628479

Sánchez-España, Javier; Boehrer, Bertram; Yusta, Iñaki

2014-04-15

447

Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.  

PubMed

Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring ?(13)C patterns among amino acids (?(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that ?(13)CAA patterns in contrast to bulk ?(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their ?(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk ?(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer ?(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. PMID:24069196

Larsen, Thomas; Ventura, Marc; Andersen, Nils; O'Brien, Diane M; Piatkowski, Uwe; McCarthy, Matthew D

2013-01-01

448

Amino acid diagenesis, organic carbon and nitrogen mineralization in surface sediments from the inner Oslofjord, Norway  

SciTech Connect

Total hydrolyzed amino acids (THAA), total organic carbon (TOC), and total nitrogen (TN) have been measured in an oxic and anoxic surface sediment from the inner Oslofjord. Downcore variations of these parameters are ascribed to both diagenesis and changes in organic matter supply, the latter being most important. These changes are most prominent in the anoxic sediment, which reflects the eutrophication history of the innermost part of the fjord. Downcore, THAA content decreased from 3.8 to 2.0 mg/g (salt-free dry weight) in the oxic sediment and from 22.3 to 3.8 mg/g in the anoxic sediment. Total amino acid nitrogen varied between 17 and 34% of total nitrogen in the oxic, and 25 and 54% in the anoxic, sediment. Organic carbon and organic nitrogen accumulation rates and depth integrated mineralization rates are about three times higher in the anoxic sediment than in the oxic sediment. Recycling of amino acids accounted for 4 to 12% of the total organic carbon and 13 to 40% of the total organic nitrogen regenerated in these sediments.

Haugen, J.E. (National Inst. of Public Health, Oslo (Norway)); Lichtentaler, R. (Norwegian Inst. for Water Research, Oslo (Norway))

1991-06-01

449

Potentially bioavailable natural organic carbon and hydrolyzable amino acids in aquifer sediments  

USGS Publications Warehouse

This study evaluated the relationship between concentrations of operationally defined potentially bioavailable organic -carbon (PBOC) and hydrolyzable amino acids (HAAs) in sediments collected from a diverse range of chloroethene--contaminated sites. Concentrations of PBOC and HAA were measured using aquifer sediment samples collected at six selected study sites. Average concentrations of total HAA and PBOC ranged from 1.96 ± 1.53 to 20.1 ± 25.6 mg/kg and 4.72 ± 0.72 to 443 ± 65.4 mg/kg, respectively. Results demonstrated a statistically significant positive relationship between concentrations of PBOC and total HAA present in the aquifer sediment (p < 0.05). Higher levels of HAA were consistently observed at sites with greater levels of PBOC and first-order decay rates. Because amino acids are known to be readily biodegradable carbon compounds, this relationship suggests that the sequential chemical extraction procedure used to measure PBOC is a useful indicator of bioavailable carbon in aquifer sediments. This, in turn, is consistent with the interpretation that PBOC measurements can be used for estimating the amount of natural organic carbon available for driving the reductive dechlorination of chloroethenes in groundwater systems.

Thomas, Lashun K.; Widdowson, Mark A.; Novak, John T.; Chapelle, Francis H.; Benner, Ronald; Kaiser, Karl

2012-01-01

450

NON-CO2 GREENHOUSE GASES IN THE ATMOSPHERE  

Microsoft Academic Search

Abstract Although global warming is generally linked to increasing levels of carbon dioxide, there are many other gases produced from industrial, agricultural, and energy-generating sources that can also cause the Earth's temperature to rise. Individually these gases are not likely to make a significant contribution, but, taken together, it is believed that they can rival the effects of carbon dioxide.

M. A. K. Khalil

1999-01-01

451

The performance of a gas and aerosol monitoring system (GAMS) for the determination of acidic water soluble organic and inorganic gases and ammonia as well as related particles from the atmosphere  

NASA Astrophysics Data System (ADS)

A new application of the quasi-simultaneous gas/particle phase sampling and analysis principle first proposed by Simon and Dasgupta (Anal. Chem. 34 (1995) 71) is described. For the first time, a gradient chromatograph is used in connection with such a sampling system to allow the simultaneous determination of major organic (formic, acetic, propionic, oxalic, malonic and succinic) and inorganic (SO 2, HNO 2, HNO 3, HCl and H 2F 2) acidic gases and related particles. Another addition to the previous systems is the analysis of cations other than ammonium from the particulate phase. The time resolution of the instrument still remains high, 1 h, during which gaseous water-soluble acidic compounds, ammonia, as well as related anionic particles and inorganic major cations are analysed. Sampling is based on diffusion in a wetted parallel plate denuder for gases and on growth in supersaturated water vapour for particles. The determination limits range from 2 ppt (acetate) to 0.4 ppb (ammonia) in the gas phase and 0.01 ?g m -3 (citric acid) to 0.79 ?g m -3 (calcium) for particulate matter. Collection efficiencies for gas and aerosol sampling were quantified and the supersaturation in the aerosol sampling apparatus investigated. The system has been used for field measurements at a background station; selected results of these measurements are presented.

Löflund, M.; Kasper-Giebl, A.; Tscherwenka, W.; Schmid, M.; Giebl, H.; Hitzenberger, R.; Reischl, G.; Puxbaum, H.