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Sample records for sodium carbonate ph

  1. Sodium carbonate poisoning

    Science.gov (United States)

    Sodium carbonate (known as washing soda or soda ash) is a chemical found in many household and industrial products. This article focuses on poisoning due to sodium carbonate. This article is for information only. Do NOT ...

  2. Carbon transport in sodium systems

    International Nuclear Information System (INIS)

    Martin Espigares, M.; Lapena, J.; La Torre, M. de

    1983-01-01

    Carbon activities in dynamic non isothermal sodium system are determined using an equilibratium method. Foils of Fe-18 w% Cr-8 W% Ni alloy with low carbon content (in the as received condition) are exposed to dynamic liquid sodium in the temperature range between 450 0 C and 700 0 C. The analysis was used to evaluate the carburization-decarburization behaviour of type 304 stainless steel exposed to sodium. (author)

  3. 21 CFR 184.1742 - Sodium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium carbonate. 184.1742 Section 184.1742 Food... Specific Substances Affirmed as GRAS § 184.1742 Sodium carbonate. (a) Sodium carbonate (Na2CO3, CAS Reg. No... ore calcined to impure soda ash and then purified; or (3) synthesized from limestone by the Solvay...

  4. 21 CFR 582.1742 - Sodium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium carbonate. 582.1742 Section 582.1742 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1742 Sodium carbonate. (a) Product. Sodium carbonate. (b) Conditions of use. This substance...

  5. Consideration of Factors Affecting Strip Effluent PH and Sodium Content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  6. Internal Active Thermal Control System (IATCS) Sodium Bicarbonate/Carbonate Buffer in an Open Aqueous Carbon Dioxide System and Corollary Electrochemical/Chemical Reactions Relative to System pH Changes

    Science.gov (United States)

    Stegman, Thomas W.; Wilson, Mark E.; Glasscock, Brad; Holt, Mike

    2014-01-01

    The International Space Station (ISS) Internal Active Thermal Control System (IATCS) experienced a number of chemical changes driven by system absorption of CO2 which altered the coolant’s pH. The natural effects of the decrease in pH from approximately 9.2 to less than 8.4 had immediate consequences on system corrosion rates and corrosion product interactions with specified coolant constituents. The alkalinity of the system was increased through the development and implementation of a carbonate/bicarbonate buffer that would increase coolant pH to 9.0 – 10.0 and maintain pH above 9.0 in the presence of ISS cabin concentrations of CO2 up to twenty times higher than ground concentrations. This paper defines how a carbonate/bicarbonate buffer works in an open carbon dioxide system and summarizes the analyses performed on the buffer for safe and effective application in the on-orbit system. The importance of the relationship between the cabin environment and the IATCS is demonstrated as the dominant factor in understanding the system chemistry and pH trends before and after addition of the carbonate/bicarbonate buffer. The paper also documents the corollary electrochemical and chemical reactions the system has experienced and the rationale for remediation of these effects with the addition of the carbonate/bicarbonate buffer.

  7. Measurement of carbon thermodynamic activity in sodium

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, F A; Zagorulko, Yu I; Kovalev, Yu P; Alekseev, V V [Institute of Physics and Power Engineering, Obninsk (USSR)

    1980-05-01

    The report presents the brief outline on system of carbon activity detecting system in sodium (SCD), operating on the carbon-permeable membrane, of the methods and the results of testing it under the experimental circulating loop conditions. The results of carbon activity sensor calibration with the use of equilibrium samples of XI8H9, Fe -8Ni, Fe -12Mn materials are listed. The behaviour of carbon activity sensor signals in sodium under various transitional conditions and hydrodynamic perturbation in the circulating loop, containing carbon bearing impurities in the sodium flow and their deposits on the surfaces flushed by sodium, are described. (author)

  8. Chemistry of carbon in dynamic sodium

    International Nuclear Information System (INIS)

    Lievens, F.; Casteels, F.

    1980-01-01

    The chemistry of carbon in sodium is described by its chemical activity measurements using alloy monitor foils, by its behaviour in the heat exchanger of the Na 2 sodium loop after 60,000 hours of operation, and by measurements with on-line meters. Efforts toward the identification of the carbon chemical states present in dynamic sodium, and responsible for the carbon chemical activity, are described. (author)

  9. Chemistry of carbon in dynamic sodium

    Energy Technology Data Exchange (ETDEWEB)

    Lievens, F; Casteels, F [SCK/CEN, Mol (Belgium)

    1980-05-01

    The chemistry of carbon in sodium is described by its chemical activity measurements using alloy monitor foils, by its behaviour in the heat exchanger of the Na 2 sodium loop after 60,000 hours of operation, and by measurements with on-line meters. Efforts toward the identification of the carbon chemical states present in dynamic sodium, and responsible for the carbon chemical activity, are described. (author)

  10. A Simple Quantitative Synthesis: Sodium Chloride from Sodium Carbonate.

    Science.gov (United States)

    Gold, Marvin

    1988-01-01

    Describes a simple laboratory procedure for changing sodium carbonate into sodium chloride by adding concentrated HCl to cause the reaction and then evaporating the water. Claims a good stoichiometric yield can be obtained in one three-hour lab period. Suggests using fume hood for the reaction. (ML)

  11. Analysis and monitoring of carbon in sodium

    Energy Technology Data Exchange (ETDEWEB)

    Lievens, F; Parmentier, C [SCK/CEN, Mol (Belgium)

    1980-05-01

    Chemical analyses used by SCK/CEN at Mol Belgium, in the carbon mass transfer studies include on-line activity measurements, and off-line carbon determinations on sodium samples and on alloys equilibrated with the carbon activity in the loop sodium. For carbon activity measurements efforts were directed to the development of EMF and diffusion type carbon meters. The Monitor tab technique was used for calibration. Chemical off-line analyses were developed for identification and measurement of total carbon and for carbon chemical states in the ppb range. Analysed chemical states are carbides, Carbonates, Carbonyl and Cyanide. (author)

  12. Analysis and monitoring of carbon in sodium

    International Nuclear Information System (INIS)

    Lievens, F.; Parmentier, C.

    1980-01-01

    Chemical analyses used by SCK/CEN at Mol Belgium, in the carbon mass transfer studies include on-line activity measurements, and off-line carbon determinations on sodium samples and on alloys equilibrated with the carbon activity in the loop sodium. For carbon activity measurements efforts were directed to the development of EMF and diffusion type carbon meters. The Monitor tab technique was used for calibration. Chemical off-line analyses were developed for identification and measurement of total carbon and for carbon chemical states in the ppb range. Analysed chemical states are carbides, Carbonates, Carbonyl and Cyanide. (author)

  13. Mixed Solvent Reactive Recrystallization of Sodium Carbonate

    NARCIS (Netherlands)

    Gaertner, R.S.

    2005-01-01

    Investigation of the reactive recrystallization of trona (sodium sesquicarbonate) and sodium bicarbonate to sodium carbonate (soda) in a mixed solvent led to the design of several alternative, less energy consumptive, economically very attractive process routes for the production of soda from all

  14. Dosage of trace carbon in sodium (1963)

    International Nuclear Information System (INIS)

    Sannier, J.; Vasseur, A.

    1963-01-01

    A wet method for dosing carbon in sodium has been developed. The carbon is oxidised in a vacuum using Van SLYKE'S solution. The carbonic acid formed is measured volumetrically; its purity can be controlled by chromatographic analysis. The results obtained show that this method makes it possible to measure carbon in concentrations of about 10 ppm. (authors) [fr

  15. The effect of sodium bicarbonate on intracellular pH using 31P-MR spectroscopy

    International Nuclear Information System (INIS)

    Nakashima, Kazuya; Kashiwagi, Shiro; Ito, Haruhide; Yamashita, Tetsuo; Kitahara, Tetsuhiro; Nakayama, Naoto; Saito, Kennichi

    1997-01-01

    This report deals with the effects of sodium bicarbonate on the intracellular pH of the brain and cerebral blood flow (CBF); five normal volunteers were studied. Intracellular pH and CBF were measured by phosphorus 31 magnetic resonance spectroscopy ( 31 P-MRS) and stable xenon computed tomography (Xe-CT), respectively. Each individual received 7% sodium bicarbonate (3.5 ml/kg body weight), infused intravenously over a 15-min period. Intracellular pH, CBF, and physiological parameters were determined before and after the injection. Intracellular pH was significantly decreased and CBF was increased. Among the physiological parameters, the hematocrit was significantly decreased and arterial pressure of carbon dioxide (PaCO 2 ), increased. These results suggest that increasing CO 2 contributes to the decrease in intracellular pH. In conclusion, three factors increase CBF during the administration of sodium bicarbonate to humans: arterial dilatation in response to carbon dioxide; decrease of the hematocrit, and intracellular cerebral acidosis. (author)

  16. Sodium to sodium carbonate conversion process

    Science.gov (United States)

    Herrmann, Steven D.

    1997-01-01

    A method of converting radioactive alkali metal into a low level disposable solid waste material. The radioactive alkali metal is atomized and introduced into an aqueous caustic solution having caustic present in the range of from about 20 wt % to about 70 wt % to convert the radioactive alkali metal to a radioactive alkali metal hydroxide. The aqueous caustic containing radioactive alkali metal hydroxide and CO.sub.2 are introduced into a thin film evaporator with the CO.sub.2 present in an amount greater than required to convert the alkali metal hydroxide to a radioactive alkali metal carbonate, and thereafter the radioactive alkali metal carbonate is separated from the thin film evaporator as a dry powder. Hydroxide solutions containing toxic metal hydroxide including one or more metal ions of Sb, As, Ba, Be, Cd, Cr, Pb, Hg, Ni, Se, Ag and T1 can be converted into a low level non-hazardous waste using the thin film evaporator of the invention.

  17. Parametric Effect of Sodium Hydroxide and Sodium Carbonate on the Potency of a Degreaser

    OpenAIRE

    Babatope Abimbola Olufemi

    2016-01-01

    Experimental and statistical analysis was carried out on the comparative effect of sodium hydroxide and sodium carbonate on the potency of a laboratory produced degreaser in this work. The materials used include; octadecyl benzene sulphonic acid, sodium hydroxide, sodium carbonate, sodium metasilicate, carboxyl methyl cellulose (C.M.C), formadelhyde, perfume, colourant and distilled water. Different samples of degreaser were produced with varying composition of sodium hydroxide and sodium car...

  18. Process for the production of sodium carbonate anhydrate

    OpenAIRE

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium carbonate and sodium bicarbonate, in a mixture containing water and an organic, water miscible or partly water miscible solvent, which solvent influences the transition temperature below which sodium...

  19. Process for the production of sodium carbonate anhydrate

    NARCIS (Netherlands)

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m<3>, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium

  20. The foil equilibration method for carbon in sodium

    Energy Technology Data Exchange (ETDEWEB)

    Borgstedt, H; Frees, G; Peric, Z [Karlsruhe Nuclear Research Center, Institute of Materials and Solid State Research, Karlsruhe (Germany)

    1980-05-01

    Among the non-metallic impurities in sodium, carbon plays an important role since at high temperatures the structural materials exposed to sodium are subject to carburization and decarburization depending on the carbon activity of the sodium. Carburization of austenitic stainless steels leads to reduction in ductility and fatigue properties whereas decarburization results in a decrease in the high temperature creep strength. A knowledge of the carbon activities in sodium will help understanding of the carbon transfer phenomena in operating sodium systems of the fast reactors, and also carbon diffusion, microstructural stability and mechanical behaviour of materials under different service conditions. An understanding of the carbon behaviour in sodium becomes difficult in view of the complexities of the different species present as elemental carbon, carbide, acetylide, carbonate, and cyanide. Carbon estimation techniques for sodium presently in use are: chemical analytical methods, on-line carbon monitors, and oil equilibration method. Various chemical methods have been developed for the estimation of different species like acetylide, cyanide, carbonate, elemental carbon, and total carbon in sodium. All these methods are time consuming and subject to various errors. The on-line monitors developed for carbon in sodium are able to give continuous indication of carbon activities and have higher sensitivity than the chemical methods. A still more simple method for the determination of carbon activities is by the foil equilibration first published by Natesan et al. Because of its simplicity like the vanadium wire equilibration for oxygen it is being used widely for the estimation of carbon activities in sodium systems. Carbon concentrations in operating sodium systems estimated by this procedure by applying solubility relation to carbon activities have yielded very low values of carbon, lower than the sensitivity limits of the chemical estimation methods. Foil

  1. The foil equilibration method for carbon in sodium

    International Nuclear Information System (INIS)

    Borgstedt, H.; Frees, G.; Peric, Z.

    1980-01-01

    Among the non-metallic impurities in sodium, carbon plays an important role since at high temperatures the structural materials exposed to sodium are subject to carburization and decarburization depending on the carbon activity of the sodium. Carburization of austenitic stainless steels leads to reduction in ductility and fatigue properties whereas decarburization results in a decrease in the high temperature creep strength. A knowledge of the carbon activities in sodium will help understanding of the carbon transfer phenomena in operating sodium systems of the fast reactors, and also carbon diffusion, microstructural stability and mechanical behaviour of materials under different service conditions. An understanding of the carbon behaviour in sodium becomes difficult in view of the complexities of the different species present as elemental carbon, carbide, acetylide, carbonate, and cyanide. Carbon estimation techniques for sodium presently in use are: chemical analytical methods, on-line carbon monitors, and oil equilibration method. Various chemical methods have been developed for the estimation of different species like acetylide, cyanide, carbonate, elemental carbon, and total carbon in sodium. All these methods are time consuming and subject to various errors. The on-line monitors developed for carbon in sodium are able to give continuous indication of carbon activities and have higher sensitivity than the chemical methods. A still more simple method for the determination of carbon activities is by the foil equilibration first published by Natesan et al. Because of its simplicity like the vanadium wire equilibration for oxygen it is being used widely for the estimation of carbon activities in sodium systems. Carbon concentrations in operating sodium systems estimated by this procedure by applying solubility relation to carbon activities have yielded very low values of carbon, lower than the sensitivity limits of the chemical estimation methods. Foil

  2. Specialists' meeting on carbon in sodium. Summary report

    International Nuclear Information System (INIS)

    1980-05-01

    The purpose of the meeting was to provide a forum for the exchange of views on: the chemistry and thermodynamics of carbon in sodium; the analysis and monitoring of carbon in sodium; the behaviour of carbon in sodium circuits; and the implications of the above in LMFBRs. The technical parts of the meeting were divided into five major sessions

  3. Specialists' meeting on carbon in sodium. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1980-05-01

    The purpose of the meeting was to provide a forum for the exchange of views on: the chemistry and thermodynamics of carbon in sodium; the analysis and monitoring of carbon in sodium; the behaviour of carbon in sodium circuits; and the implications of the above in LMFBRs. The technical parts of the meeting were divided into five major sessions.

  4. Scientific Opinion on the safety evaluation of the active substances, sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate, bentonite, sodium chloride, sodium carbonate for use in active food contact materials

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2013-01-01

    This scientific opinion of the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the powder mixture of the active substances sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate (FCM substance No 1009), bentonite (CAS No 1302-78-9, FCM No 393), sodium chloride (CAS No 7647-14-5, FCM No 985), sodium carbonate (CAS No 497-19-8, FCM No 1008) which are intended to be used as combined oxygen generator and carbon...

  5. Dosage of trace carbon in sodium (1963); Dosage de traces de carbone dans le sodium (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Sannier, J; Vasseur, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    A wet method for dosing carbon in sodium has been developed. The carbon is oxidised in a vacuum using Van SLYKE'S solution. The carbonic acid formed is measured volumetrically; its purity can be controlled by chromatographic analysis. The results obtained show that this method makes it possible to measure carbon in concentrations of about 10 ppm. (authors) [French] Une methode de dosage par voie humide du carbone dans le sodium a ete mise au point. L'oxydation du carbone par la solution de Van SLYKE est realisee sous vide. Le gaz carbonique forme est dose volumetriquement; sa purete peut etre controlee par analyse chromatographique. Les resultats obtenus montrent que cette methode permet de doser des teneurs en carbone de l'ordre de 10 ppm. (auteurs)

  6. The effect of sodium bicarbonate on intracellular pH using {sup 31}P-MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Kazuya; Kashiwagi, Shiro; Ito, Haruhide [Yamaguchi Univ., Ube (Japan). School of Medicine; Yamashita, Tetsuo; Kitahara, Tetsuhiro; Nakayama, Naoto; Saito, Kennichi

    1997-03-01

    This report deals with the effects of sodium bicarbonate on the intracellular pH of the brain and cerebral blood flow (CBF); five normal volunteers were studied. Intracellular pH and CBF were measured by phosphorus 31 magnetic resonance spectroscopy ({sup 31}P-MRS) and stable xenon computed tomography (Xe-CT), respectively. Each individual received 7% sodium bicarbonate (3.5 ml/kg body weight), infused intravenously over a 15-min period. Intracellular pH, CBF, and physiological parameters were determined before and after the injection. Intracellular pH was significantly decreased and CBF was increased. Among the physiological parameters, the hematocrit was significantly decreased and arterial pressure of carbon dioxide (PaCO{sub 2}), increased. These results suggest that increasing CO{sub 2} contributes to the decrease in intracellular pH. In conclusion, three factors increase CBF during the administration of sodium bicarbonate to humans: arterial dilatation in response to carbon dioxide; decrease of the hematocrit, and intracellular cerebral acidosis. (author)

  7. Sodium Hypochlorite and Sodium Bromide Individualized and Stabilized Carbon Nanotubes in Water

    KAUST Repository

    Xu, Xuezhu

    2017-09-20

    Aggregation is a major problem for hydrophobic carbon nanomaterials such as carbon nanotubes (CNTs) in water because it reduces the effective particle concentration, prevents particles from entering the medium, and leads to unstable electronic device performances when a colloidal solution is used. Molecular ligands such as surfactants can help the particles to disperse, but they tend to degrade the electrical properties of CNTs. Therefore, self-dispersed particles without the need for surfactant are highly desirable. We report here, for the first time to our knowledge, that CNT particles with negatively charged hydrophobic/water interfaces can easily self-disperse themselves in water via pretreating the nanotubes with a salt solution with a low concentration of sodium hypochlorite (NaClO) and sodium bromide (NaBr). The obtained aqueous CNT suspensions exhibit stable and superior colloidal performances. A series of pH titration experiments confirmed the presence and role of the electrical double layers on the surface of the salted carbon nanotubes and of functional groups and provided an in-depth understanding of the phenomenon.

  8. Sodium Hypochlorite and Sodium Bromide Individualized and Stabilized Carbon Nanotubes in Water

    KAUST Repository

    Xu, Xuezhu; Zhou, Jian; Colombo, Veronica; Xin, Yangyang; Tao, Ran; Lubineau, Gilles

    2017-01-01

    Aggregation is a major problem for hydrophobic carbon nanomaterials such as carbon nanotubes (CNTs) in water because it reduces the effective particle concentration, prevents particles from entering the medium, and leads to unstable electronic device performances when a colloidal solution is used. Molecular ligands such as surfactants can help the particles to disperse, but they tend to degrade the electrical properties of CNTs. Therefore, self-dispersed particles without the need for surfactant are highly desirable. We report here, for the first time to our knowledge, that CNT particles with negatively charged hydrophobic/water interfaces can easily self-disperse themselves in water via pretreating the nanotubes with a salt solution with a low concentration of sodium hypochlorite (NaClO) and sodium bromide (NaBr). The obtained aqueous CNT suspensions exhibit stable and superior colloidal performances. A series of pH titration experiments confirmed the presence and role of the electrical double layers on the surface of the salted carbon nanotubes and of functional groups and provided an in-depth understanding of the phenomenon.

  9. Effects of sodium carbonate and sodium bicarbonate on yield and characteristics of Pacific white shrimp (Litopenaeus vannamei).

    Science.gov (United States)

    Chantarasuwan, C; Benjakul, S; Visessanguan, W

    2011-08-01

    Effects of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) on yield and characteristics of Pacific white shrimp (Litopenaeus vannamei) were studied. Shrimp soaked in 2.5% NaCl containing both compounds at different levels of pH (5.5, 7, 8.5, 10 and 11.5) showed an increase in the weight gain and cooking yield and a reduced cooking loss as pH of solutions increased (p<0.05). Increases in pH and salt content in soaked shrimp muscle were obtained with increasing pH (p<0.05). Higher pH of soaking solution partially solubilized proteins in the muscle as well as carotenoproteins. pH of solutions above 8.5 led to the pronounced leaching of pigments, associated with the lowered redness of cooked shrimp. Shear force of raw and cooked shrimp continuously decreased as pH of solution increased (p<0.05). Solution containing 2.5% NaCl and 2.0% NaHCO3 (pH 8.5) was recommended for treatment of white shrimp as a promising alternative for phosphates to increase the yield and to lower cooking loss without any negative effect on sensory properties.

  10. Behaviour of carbon-bearing impurity suspensions in sodium loops

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, F A; Zagorulko, Yu I; Alexseev, V V [Institute of Physics and Power Engineering, Obninsk (USSR)

    1980-05-01

    The experimental estimation results of the carbon-bearing impurity particle sizes in sodium by the sedimentometric analysis methods are presented. The techniques and results of the mass transfer calculations between the sodium flows contained the carbon-bearing impurity disperse phase, and the channel walls, the carbon particles solution kinetics and the soluble carbon near-wall concentration in channel with allowance for the flow-wall mass transfer processes, are given. (author)

  11. Behaviour of carbon-bearing impurity suspensions in sodium loops

    International Nuclear Information System (INIS)

    Kozlov, F.A.; Zagorulko, Yu.I.; Alexseev, V.V.

    1980-01-01

    The experimental estimation results of the carbon-bearing impurity particle sizes in sodium by the sedimentometric analysis methods are presented. The techniques and results of the mass transfer calculations between the sodium flows contained the carbon-bearing impurity disperse phase, and the channel walls, the carbon particles solution kinetics and the soluble carbon near-wall concentration in channel with allowance for the flow-wall mass transfer processes, are given. (author)

  12. Consideration of factors affecting strip effluent pH and sodium content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  13. The Renal Sodium Bicarbonate Cotransporter NBCe2: Is It a Major Contributor to Sodium and pH Homeostasis?

    Science.gov (United States)

    Felder, Robin A; Jose, Pedro A; Xu, Peng; Gildea, John J

    2016-09-01

    The sodium bicarbonate cotransporter (NBCe2, aka NBC4) was originally isolated from the human testis and heart (Pushkin et al. IUBMB Life 50:13-19, 2000). Subsequently, NBCe2 was found in diverse locations where it plays a role in regulating sodium and bicarbonate transport, influencing intracellular, extracellular, interstitial, and ultimately plasma pH (Boron et al. J Exp Biol. 212:1697-1706, 2009; Parker and Boron, Physiol Rev. 93:803-959, 2013; Romero et al. Mol Asp Med. 34:159-182, 2013). NBCe2 is located in human and rodent renal-collecting duct and proximal tubule. While much is known about the two electrogenic sodium bicarbonate cotransporters, NBCe1 and NBCe2, in the regulation of sodium homeostasis and pH balance in the rodent kidney, little is known about their roles in human renal physiology. NBCe2 is located in the proximal tubule Golgi apparatus under basal conditions and then disperses throughout the cell, but particularly into the apical membrane microvilli, during various maneuvers that increase intracellular sodium. This review will summarize our current understanding of the distribution and function of NBCe2 in the human kidney and how genetic variants of its gene, SLC4A5, contribute to salt sensitivity of blood pressure.

  14. Sodium-carbonate co-substituted hydroxyapatite ceramics

    Directory of Open Access Journals (Sweden)

    Zoltan Z. Zyman

    2013-12-01

    Full Text Available Powders of sodium-carbonate co-substituted hydroxyapatite, having sodium content in the range of 0.25–1.5 wt.% with a 0.25 wt.% step, were prepared by a precipitation-solid state reaction route. Compacts of the powders were sintered in a CO2 flow (4 mL/min at 1100 °C for 2 h. The sintered ceramics contained sodium and carbonate ions in the ranges of 0–1.5 wt.% and 1.3–6 wt.%, respectively, which are typical impurity concentrations in biological apatite. A relationship between sodium and carbonate contents and the type of carbonate substitution was found. The total carbonate content progressively increased with the sodium content. The obtained ceramics showed an AB-type carbonate substitution. However, the substitution became more B-type as the sodium content increased. As a result, the carbonation was almost B-type (94 % for the highest sodium content (1.5 wt.%.

  15. Carbon in sodium: a status review of the USA R and D work

    International Nuclear Information System (INIS)

    McCown, J.J.; Bagnall, C.

    1979-01-01

    A review is presented concerning R and D work on carbon in sodium with reference to LMFBR primary coolant circuits. The chemistry of carbon in sodium, analysis and monitoring of carbon in sodium, carbon meters, and problems of carbon in sodium are described. 31 references

  16. THE SODIUM PREVALENCE IN CARBONATED SOFT DRINKS SOLD IN BRAZIL

    Directory of Open Access Journals (Sweden)

    Sandra Fernanda Nunes

    2012-12-01

    Full Text Available The carbonated soft drinks intake has changed the children eating habits. This factor may be directly associated with arterial hypertension due the high consumption of sodium present in foods and drinks industrialized. This study was to compare sodium levels between two different types of carbonated soft drinks, carbonated sugar drinks and diet drinks to define what type of drink has the lowest sodium content and alerting healthcare professionals about the presence of sodium in industrialized beverages. The study included labels of carbonated soft drinks n = 33 – sugar drinks (n = 21 or diet drinks (n = 12 – of five different flavors.All carbonated soft drinks evaluated have sodium in its composition. However, the sodium presence in carbonated sugar drinks was significantly lower when compared with carbonated diet drinks (69.05 ± 16.55 vs. 145.30 ± 47.36mg Na/l, respectively.Studies to identify children's eating habits related with increased consumption of foods and drinks manufactured are needed to identify, reduce and prevent high blood pressure.

  17. Carbon Dioxide for pH Control

    Energy Technology Data Exchange (ETDEWEB)

    Wagonner, R.C.

    2001-08-16

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

  18. Reducing biomass recalcitrance via mild sodium carbonate pretreatment.

    Science.gov (United States)

    Mirmohamadsadeghi, Safoora; Chen, Zhu; Wan, Caixia

    2016-06-01

    This study examined the effects of mild sodium carbonate (Na2CO3) pretreatment on enzymatic hydrolysis of different feedstocks (i.e., corn stover, Miscanthus, and switchgrass). The results showed that sodium carbonate pretreatment markedly enhanced the sugar yields of the tested biomass feedstocks. The pretreated corn stover, Miscanthus, and switchgrass gave the glucose yields of 95.1%, 62.3%, and 81.3%, respectively, after enzymatic hydrolysis. The above glucose yields of pretreated feedstocks were 2-4 times that of untreated ones. The pretreatment also enhanced the xylose yields, 4 times for corn stover and 20 times for both Miscanthus and switchgrass. Sodium carbonate pretreatment removed 40-59% lignin from the tested feedstocks while preserving most of cellulose (sodium carbonate pretreatment was effective for reducing biomass recalcitrance and subsequently improving the digestibility of lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Reaction velocity of sodium hydration in humid air and sodium carbonation in humid carbon dioxide atmosphere. Fundamental study on sodium carbonate process in FBR bulk sodium coolant disposal technology

    International Nuclear Information System (INIS)

    Tadokoro, Yutaka; Yoshida, Eiichi

    1999-11-01

    A sodium carbonate processing method, which changes sodium to sodium carbonate and/or sodium bicarbonate by humid carbon dioxide, has been examined and about to be applied to large test loops dismantling. However, that the basic data regarding the progress of the reaction is insufficient on the other hand, is a present condition. The present report therefore aims at presenting basic data regarding the reaction velocity of sodium hydration in humid air and sodium carbonation in humid carbon dioxide atmosphere, and observing the reaction progress, for the application to large test loops dismantling. The test result is summarized as follows. (1) Although the reaction velocity of sodium varied with sodium specimen sizes and velocity measurement methods, the reaction velocity of sodium hydration was in about 0.16 ∼ 0.34 mmh -1 (0.016 ∼ 0.033g cm -2 h -1 , 6.8x10 -4 ∼ 1.4x10 -3 mol cm -2 h -1 ) and that of sodium carbonation was in about 0.16 ∼ 0.27mmh -1 (0.016 ∼ 0.023g cm -2 h -1 , 6.8x10 -4 ∼ 1.1x10 -3 mol cm -2 h -1 ) (26 ∼ 31degC, RH 100%). (2) The reaction velocity of sodium in carbon dioxide atmosphere was greatly affected by vapor partial pressure (absolutely humidity). And the velocity was estimated in 0.08 ∼ 0.12mmh -1 (0.008 ∼ 0.012g cm -2 h -1 , 3.4x10 -4 ∼ 5.2x10 -4 mol cm -2 h -1 ) in the carbon dioxide atmosphere, whose temperature of 20degC and relative humidity of 80% are assumed real sodium carbonate process condition. (3) By the X-ray diffraction method, NaOH was found in humid air reaction product. Na 2 CO 3 , NaHCO 3 were found in carbon dioxide atmosphere reaction product. It was considered that Sodium changes to NaOH, and subsequently to NaHCO 3 through Na 2 CO 3 . (4) For the application to large test loops dismantling, it is considered possible to change sodium to a target amount of sodium carbonate (or sodium bicarbonate) by setting up gas supply quantity and also processing time appropriately according to the surface area

  20. Eliminating radium from uranium mill acid effluent with barium chloride-sodium carbonate precipitation

    International Nuclear Information System (INIS)

    Xiao Jiayuan

    1998-01-01

    The eliminating radium procedure, barium chloride-sodium carbonate-sand filtering, being used, radium can be eliminated to 3.7 x 10 -2 Bq/L order of magnitude from uranium mill acid effluents which contain 3.7 Bq/L Ra and pH 6∼9 when Ba 2+ is added by 3∼5 mg per litre, Na 2 CO 3 5mg. The radium elimination rate is more than 90%

  1. pH and salivary sodium bicarbonate in cancer patients: correlation with seric concentration.

    Science.gov (United States)

    Rojas-Morales, Thais; Navas, Rita; Viera, Ninoska; Alvarez, Carmen Julia; Chaparro, Neira

    2008-07-01

    To determine the correlation between pH and bicarbonate of soda in blood and saliva in child and adolescent patients during the administration of 3 g/m2 of methotrexate. A controlled clinical test was performed on 23 patients diagnosed with Acute Lymphoblastic Leukemia. Ages ranged from 4 to 18. The Spearman Correlation Coefficient was used to interpret the data. No significant correlation was found between pH levels and seric and salivary sodium bicarbonate. However, there was a significant correlation between the levels of sodium bicarbonate in the body fluids evaluated (rs 0.2576, p=0.0354). Changes modifying the microenvironment of the oral cavity probably do not allow saliva to be used to determine blood pH and seric bicarbonate.

  2. Effects of Inulin and Sodium Carbonate in Phosphate-Free Restructured Poultry Steaks

    Science.gov (United States)

    Öztürk, B.; Serdaroğlu, M.

    2017-09-01

    Recently inorganic phosphates used in meat product formulations have caused negative impact on consumers due to their potential health risks. Therefore, utilization of natural ingredients as phosphate replacers has come into prominence as a novel research topic to meet consumer demands for clean-label trends. In this study, we objected to investigate the effects of inulin utilization either in the powder or gelled form, alone or in combination with sodium carbonate on quality of phosphate-free restructured chicken steaks. Total moisture, protein, lipid and ash values of the trial groups were in the range of 71.54-75.46%, 22.60-24.31%, 0.94-1.70% and 1.45-2.13%, respectively. pH of the samples was between 6.18-6.39, significant increments were recorded in samples containing inulin with sodium carbonate. L*, a* and b* values were recorded as 78.92-81.05, 1.76-3.05 and 10.80-11.94, respectively, where use of gelled inulin resulted in changes of L* and a* values. Utilization of inulin in combination with sodium carbonate decreased cook loss and enhanced product yield. Sensory scores in control group with phosphate showed a similar pattern to sensory scores in groups with inulin and sodium carbonate. During storage, purge loss and lipid oxidation rate were similar in control and inulin + sodium carbonate samples. The results showed that use of inulin in combination with sodium carbonate provided equivalent physical, chemical and sensory quality to phosphates in restructured chicken steaks.

  3. Survey on investigations on carbon chemistry and transfer in sodium

    International Nuclear Information System (INIS)

    Menken, G.; Jung, J.

    1980-01-01

    The operation of Liquid Metal Fast Reactor Systems at elevated temperatures requires the control of carbon impurities in sodium and of carbon transfer related to the metallic structural materials wetted by the coolant. This review is aimed at providing a brief statement of the objectives and accomplishments in some major areas of the investigations on the behaviour of carbon impurities in the heat transfer circuits of the SNR-300 reactor presently under construction at Kalkar on the Rhine

  4. Adsorption of sodium dodecylbenzenesulfonate on activated carbons: effects of solution chemistry and presence of bacteria.

    Science.gov (United States)

    Bautista-Toledo, M I; Méndez-Díaz, J D; Sánchez-Polo, M; Rivera-Utrilla, J; Ferro-García, M A

    2008-01-01

    The objective of the present investigation was to determine the effectiveness of activated carbon in removing sodium dodecylbenzenesulfonate (SDBS) and to analyze the chemical and textural characteristics of the activated carbons that are involved in the adsorption process. Studies were also performed on the influence of operational variables (pH, ionic strength, and presence of microorganisms) and on the kinetics and interactions involved in the adsorption of this pollutant on activated carbon. The kinetics study of SDBS adsorption revealed no problems in its diffusion on any of the activated carbons studied, and Weisz-Prater coefficient (C WP) values were considerably lower than unity for all activated carbons studied. SDBS adsorption isotherms on these activated carbons showed that: (i) adsorption capacity of activated carbons was very high (260-470 mg/g) and increased with larger surface area; and (ii) dispersive interactions between SDBS and carbon surface were largely responsible for the adsorption of this pollutant. SDBS adsorption was not significantly affected by the solution pH, indicating that electrostatic adsorbent-adsorbate interactions do not play an important role in this process. The presence of electrolytes (NaCl) in the medium favors SDBS adsorption, accelerating the process and increasing adsorption capacity. Under the working conditions used, SDBS is not degraded by bacteria; however, the presence of bacteria during the process accelerates and increases SDBS adsorption on the activated carbon. Microorganism adsorption on the activated carbon surface increases its hydrophobicity, explaining the results observed.

  5. Carbon in sodium - A review of work in the UK

    Energy Technology Data Exchange (ETDEWEB)

    Thorley, A W; Hobdell, M R [CEGB, Berkeley Nuclear Laboratories, Berkely, Gloucestershire (United Kingdom)

    1980-05-01

    It has been shown experimentally that when a difference in carbon potential exists between two points in a sodium circuit, carbon will move from regions of high carbon potential to regions of low carbon potential. Instrumental in this transport process is the liquid sodium which provides an efficient. means of transport between sources and sinks. In terms of operation of LMFBRs the point of concern is that impairment of mechanical properties may occur if significant amounts of carbon are gained or lost from structures exposed to sodium. In the UK the behaviour of carbon in liquid sodium is being studied at AERE Harwell, Berkeley Nuclear Laboratories (BNL), the Dounreay Nuclear Establishment (DNE), and the Risley Nuclear Laboratories (RNL). The scope of this review reflects the type of work being carried out at various establishments and presents our current views on certain topics. A survey of the UK position and an indication of where more work is required is also included in the paper. Specialist material is provided in the form of appendices.

  6. Carbon in sodium - A review of work in the UK

    International Nuclear Information System (INIS)

    Thorley, A.W.; Hobdell, M.R.

    1980-01-01

    It has been shown experimentally that when a difference in carbon potential exists between two points in a sodium circuit, carbon will move from regions of high carbon potential to regions of low carbon potential. Instrumental in this transport process is the liquid sodium which provides an efficient. means of transport between sources and sinks. In terms of operation of LMFBRs the point of concern is that impairment of mechanical properties may occur if significant amounts of carbon are gained or lost from structures exposed to sodium. In the UK the behaviour of carbon in liquid sodium is being studied at AERE Harwell, Berkeley Nuclear Laboratories (BNL), the Dounreay Nuclear Establishment (DNE), and the Risley Nuclear Laboratories (RNL). The scope of this review reflects the type of work being carried out at various establishments and presents our current views on certain topics. A survey of the UK position and an indication of where more work is required is also included in the paper. Specialist material is provided in the form of appendices

  7. Promoting effect of active carbons on methanol dehydrogenation on sodium carbonate - hydrogen spillover

    OpenAIRE

    Su, S.; Prairie, M.; Renken, A.

    1993-01-01

    Methanol dehydrogenation to formaldehyde was conducted in a fixed-bed flow reactor with sodium carbonate catalyst mixed with active carbons or transition metals. The additives promoted the reaction rate at 880-970 K without modifying formaldehyde selectivity. This effect increases with increasing carbon content in the carbon-carbonate mixture. Activation energy of methanol conversion is the same for the mixture and the carbonate alone. Temperature-programmed desorption experiments showed that...

  8. Measurement of carbon activity of sodium using nickel tabs and the Harwell Carbon Meter - Preliminary experience

    International Nuclear Information System (INIS)

    Blundell, A.; Thorley, A.W.

    1980-01-01

    Carbon can have an important effect on the mechanical properties of certain constructional materials likely to be used in the LMFBRs. Transfer of carbon will occur between the metal and the sodium at any particular location to bring the chemical potential of carbon in both components to the sam: value. Thus, in a mixed system containing austenitic stainless steel and unstabilized ferritic steel, carbon could be transferred by the sodium from the high carbon activity ferritic to the lower activity austenitic steel. Loss of carbon from the unstabilized ferritic steel leads to a weaker, more ductile material, while carburization of the stainless steel could lead to its embrittlement. Similarly carbon entering the coolant in the form of oil from leaking mechanical pumps could have similar effects on the mechanical property of stainless steels. In the light of these possibilities it is essential to measure the carbon activity of the sodium so that its effect on materials properties can be predicted

  9. Measurement of carbon activity of sodium using nickel tabs and the Harwell Carbon Meter - Preliminary experience

    Energy Technology Data Exchange (ETDEWEB)

    Blundell, A; Thorley, A W [UKAEA, Risley, Warrington, Cheshire (United Kingdom)

    1980-05-01

    Carbon can have an important effect on the mechanical properties of certain constructional materials likely to be used in the LMFBRs. Transfer of carbon will occur between the metal and the sodium at any particular location to bring the chemical potential of carbon in both components to the sam: value. Thus, in a mixed system containing austenitic stainless steel and unstabilized ferritic steel, carbon could be transferred by the sodium from the high carbon activity ferritic to the lower activity austenitic steel. Loss of carbon from the unstabilized ferritic steel leads to a weaker, more ductile material, while carburization of the stainless steel could lead to its embrittlement. Similarly carbon entering the coolant in the form of oil from leaking mechanical pumps could have similar effects on the mechanical property of stainless steels. In the light of these possibilities it is essential to measure the carbon activity of the sodium so that its effect on materials properties can be predicted.

  10. Influence of sodium carbonate on decomposition of formic acid by pulsed discharge plasma inside bubble in water

    Science.gov (United States)

    Iwabuchi, Masashi; Takahashi, Katsuyuki; Takaki, Koichi; Satta, Naoya

    2016-07-01

    The influence of sodium carbonate on the decomposition of formic acid by discharge inside bubbles in water was investigated experimentally. Oxygen or argon gases were injected into the water through a vertically positioned glass tube, in which the high-voltage wire electrode was placed to generate plasmas at low applied voltage. The concentration of formic acid was determined by ion chromatography. In the case of sodium carbonate additive, the pH increased owing to the decomposition of the formic acid. In the case of oxygen injection, the percentage of conversion of formic acid increased with increasing pH because the reaction rate of ozone with formic acid increased with increasing pH. In the case of argon injection, the percentage of conversion was not affected by the pH owing to the high rate loss of hydroxyl radicals.

  11. Crescimento de Acidovorax avenae subsp. citrulli sob diferentes temperaturas, pH, concentrações de cloreto de sódio e fontes de carbono Growth of Acidovorax avenae subsp. citrulli under different variable temperature, pH, sodium chloride concentrations and carbon sources

    Directory of Open Access Journals (Sweden)

    Márcia Tanajura Cavalcanti

    2005-12-01

    Full Text Available O objetivo deste estudo foi determinar o efeito da temperatura (0 a 45°C, pH (4 a 10 e concentração de NaCl (1 a 10% sobre o crescimento de Acidovorax avenae subsp. citrulli (Aac. Quatro estirpes de Aac foram cultivadas em meio de cultura líquido específico e o crescimento avaliado pela absorbância (580nm. Os dados obtidos foram submetidos à análise de regressão não linear. O crescimento das estirpes também foi avaliado em caldo base para fermentação contendo 1% dos carboidratos glicose, galactose, ramnose, sacarose, lactose, maltose, amido, inulina, manitol, dulcitol, sorbitol e salicina, indicada pela mudança da cor do meio. Com base nas análises de regressão, as temperaturas mínima, ótima e máxima para crescimento de Aac foram, respectivamente, 1, 32 e 41°C; o pH ótimo para crescimento dessa bactéria foi 7,4 com os extremos mínimo de 4,0 e máximo de 10,8 e; o crescimento de Aac decresceu com o aumento da concentração de NaCl, sendo o nível de 6,2% letal. Todos os carboidratos testados foram utilizados pelas estirpes de Aac como fonte de carbono, com pequena variação de crescimento observada pela velocidade e intensidade da utilização do substrato com produção de ácido.The objective of this study was to determine the effect of temperature (0 to 45°C, pH (4 to 10 and NaCl concentration (1 to 10% in the growth of Acidovorax avenae subsp. citrulli (Aac. Four Aac strains were grown in specific liquid medium, and their growth evaluated by absorbance (580nm. Data were submitted to nonlinear regression analysis. The bacterial growth was also studied in fermentation broth containing 1% of fermentable carbohydrates, glucose, galactose, rhamnose, sucrose, lactose, maltose, starch, inulin, mannitol, dulcitol, sorbitol and salicin, being evaluated by medium color change. Based upon regression analyses, the minimum, optimum and maximum temperatures for Aac growth were respectively 1, 32 and 41°C; the optimum pH for Aac

  12. Using Sodium Hydrogen Carbonate for Foaming Polymers

    Directory of Open Access Journals (Sweden)

    Satin Lukáš

    2016-09-01

    Full Text Available All plastics products are made of the essential polymer mixed with a complex blend of materials known collectively as additives. Without additives, plastics would not work, but with them, they can be made safer, cleaner, tougher and more colourful. Additives cost money, but by reducing production costs and making products live longer, they help us save money and conserve the world's precious raw material reserves. In fact, our world would be a lot less safe, a lot more expensive and a great deal duller without the additives that turn basic polymers into useful plastics. One of these additives is sodium bicarbonate. Influence of sodium bicarbonate on properties of the product made of polystyrene was observed in the research described in this paper. Since polystyrene is typically used as a material for electrical components, the mechanical properties of tensile strength and inflammability were measured as a priority. Inflammability parameters were measured using a cone calorimeter.

  13. Titration of Monoprotic Acids with Sodium Hydroxide Contaminated by Sodium Carbonate.

    Science.gov (United States)

    Michalowski, Tadeusz

    1988-01-01

    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)

  14. Measurement of carbon activity in sodium and steel and the behaviour of carbon-bearing species

    International Nuclear Information System (INIS)

    Rajendran Pillai, S.; Ranganathan, R.; Mathews, C.K.

    1988-01-01

    Carburization or decarburization of structural materials in a sodium system depends on the local differences in carbon activity. The behaviour of carbon-bearing species in sodium influences its carbon activity. In order to understand the behaviour of carbon in these systems, an electrochemical carbon meter was fabricated in our laboratory. The original version of this meter was capable of operating in the temperature range of 850-980 K. Studies are carried out to extend this lower limit of temperature. Employing the carbon meter, experiments were carried out to understand the behaviour of carbon-bearing species. Gas equilibration experiments were also carried out with the same view. A new method for measuring the carbon activity in steels are described which employs the carbon meter. A review on these investigations and the conclusions reached on the behaviour of carbon in fast reactor loops are described

  15. Effect of orally administered sodium bicarbonate on caecal pH.

    Science.gov (United States)

    Taylor, E A; Beard, W L; Douthit, T; Pohlman, L

    2014-03-01

    Caecal acidosis is a central event in the metabolic cascade that occurs following grain overload. Buffering the caecal acidosis by enterally administered sodium bicarbonate (NaHCO3 ) may be beneficial to affected horses. To determine the effect and duration of enterally administered NaHCO3 on caecal pH in healthy horses. Experimental study using horses with caecal cannulas. Nine horses had been previously fitted with a caecal cannula. Six horses received 1.0 g/kg bwt NaHCO3 and 3 control horses were given 3 l of water via nasogastric tube. Clinical parameters, water consumption, venous blood gases, caecal pH, faecal pH and faecal water content were measured at 6 h intervals over a 36 h study period. Horses that received enterally administered NaHCO3 had significantly increased caecal pH that lasted the duration of the study. Treated horses increased their water intake, and developed metabolic alkalaemia, significantly increased plasma sodium concentrations and significantly decreased plasma potassium concentrations. Enterally administered NaHCO3 may be beneficial in buffering caecal acidosis. © 2013 EVJ Ltd.

  16. The Effects of Sodium Bicarbonate and Sodium Citrate on Blood pH, HCO3-, Lactate Metabolism and Time to Exhaustion

    Directory of Open Access Journals (Sweden)

    Soetanto Hartono

    2017-02-01

    Full Text Available The purpose of this study was to compare the effects of sodium bicarbonate and sodium citrate in increasing lactate concentration, blood pH, HCO3-, and time to exhaustion. Increased time to exhaustion is an advantage since the athletes can do more anaerobic work. Exhaustion could be delayed by increasing HCO3- to catch H+ produced by lactate metabolism to form H2O and CO2. The design of this research was randomized pretest posttest control group design. Thirty badminton student players were randomly selected and randomly assigned to three groups. The first group (the control group was given placebo, NaCl .9 g/dl, the second group was given sodium bicarbonate 300 mg/kg in 500 ml aqua, and the third group was given sodium citrate 300 mg/kg in 500 ml aqua. Blood pH and bicarbonate ion (HCO3- were measured through Opti Medical Blood gas Analyzer. Lactate was measured by Cobas Roche lactate Analyzer. Data was analyzed using Manova with .05 significant level. Blood pH of the groups taking sodium bicarbonate and sodium citrate were higher significantly against control group (p.05. Sodium bicarbonate is better than sodium citrate, although both were better than control (p<.05. Sodium bicarbonate is better than sodium citrate in increasing blood pH and time to exhaustion. The disadvantage of using sodium bicarbonate is that it can cause gastrointestinal problem and headache, so it is not advisable to be used by athletes who have the symptoms.

  17. Microenvironmental pH measurement during sodium naproxenate dissolution in acidic medium by UV/vis imaging

    DEFF Research Database (Denmark)

    Ostergaard, Jesper; Jensen, Henrik; Larsen, Susan W

    2014-01-01

    Variable dissolution from sodium salts of drugs containing a carboxylic acid group after passing the acidic environment of the stomach may affect oral bioavailability. The aim of the present proof of concept study was to investigate pH effects in relation to the dissolution of sodium naproxenate...... in 0.01M hydrochloric acid. For this purpose a UV/vis imaging-based approach capable of measuring microenvironmental pH in the vicinity of the solid drug compact as well as monitoring drug dissolution was developed. Using a pH indicating dye real-time spatially resolved measurement of pH was achieved....... Sodium naproxenate, can significantly alter the local pH of the dissolution medium, is eventually neutralized and precipitates as the acidic species naproxen. The developed approach is considered useful for detailed studies of pH dependent dissolution phenomena in dissolution testing....

  18. Effect of initial pH in levan production by Zymomonas mobilis immobilized in sodium alginate

    Directory of Open Access Journals (Sweden)

    Vidiany Aparecida Queiroz Santos

    2014-04-01

    Full Text Available Zymomonas mobilis was immobilized using a cell suspension fixed to 8.6 x 107 CFU mL-1 by spectrophotometry. This biomass was suspended in sodium alginate solution (3% that was dropped with a hypodermic syringe into 0.2 M calcium chloride solution. Was test two initial pH of fermentation medium (4 and 5 and different sucrose concentrations 15, 20, 25, 30 and 35% at 30˚C, without stirring for 24, 48, 72 and 96 hours. The levan production to pH 4 was high in sucrose 25% for 24 (16.51 g L-1 and 48 (15.31 g L-1 hours. The best values obtained to pH 5 was in sucrose 35% during 48 (22.39 g L-1 and 96 (23.5 g L-1 hours, respectively. The maximum levan yield was 40.8% and 22.47% in sucrose 15% to pH 4 and 5, respectively. Substrate consumption to pH 4 was bigger in sucrose 15 (56.4% and 20% (59.4% and to pH 5 was in 25 (68.85% and 35% (64.64%. In relation to immobilization efficiency, Zymomonas mobilis showed high adhesion and colonization in support, indicated by cell growth increased from 107 to 109 CFU mL-1 during fermentation time.

  19. Carbon and nitrogen transport in sodium systems

    International Nuclear Information System (INIS)

    Schrock, S.L.; Shiels, S.A.; Bagnall, C.

    1976-01-01

    Materials for the liquid metal cooled fast breeder reactor will be exposed to high temperature sodium for time periods up to 30 years. One consequence of this exposure will be changes in the interstitial element concentrations of the alloys and concomitant alterations in their mechanical behavior characteristics. Several ongoing technology programs have as their objective a quantitative definition of the rate and extent of this interstitial movement. The paper summarizes the status of these programs and reports in detail on the results of a recently completed, USERDA funded program at the Advanced Reactors Division of Westinghouse. These results, while substantiating earlier reported trends on interstitial movement, indicate the problem is not as severe as initially estimated. Moreover, the present wastage allowance for most reactor components contains sufficient conservatism to compensate for changes in mechanical strength resulting from this change in interstitial concentration

  20. Controlling the pH of acid cheese whey in a two-stage anaerobic digester with sodium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ghaly, A.E.; Ramkumar, D.R.

    1999-07-01

    Anaerobic digestion of cheese whey offers a two-fold benefit: pollution potential reduction and biogas production. The biogas, as an energy source, could be used to reduce the consumption of traditional fuels in the cheese plant. However, as a result of little or no buffering capacity of whey, the pH of the anaerobic digester drops drastically and the process is inhibited. In this study, the effect of controlling the pH of the second chamber of a two-stage, 150 L anaerobic digester operating on cheese whey on the quality and quantity of biogas and the pollution potential reduction, was investigated using sodium hydroxide. The digester was operated at a temperature of 35 C and a hydraulic retention time of 15 days for three runs (no pH control, pH control with no reseeding, and pH control with reseeding) each lasting 50 days. The results indicated that operating the digester without pH control resulted in a low pH (3.3) which inhibited the methanogenic bacteria. The inhibition was irreversible and the digester did not recover (no methane production) when the pH was restored to 7.0 without reseeding, as the observed increased gas production was a false indication of recovery because the gas was mainly carbon dioxide. The addition of base resulted in a total alkalinity of 12,000 mg L as CaCO{sub 3}. When the system was reseeded and the pH controlled, the total volatile acid concentration was 15,100 mg L (as acetic acid), with acetic (28 %), propionic (21%), butyric (25%), valeric (8%), and caproic (15%) acids as the major constituents. The biogas production was 62.6 L d (0.84m{sup 3}m{sup 3} d) and the methane content was 60.7%. Reductions of 27.3, 30.4 and 23.3 % in the total solids, chemical oxygen demand and total Kjeldahl nitrogen were obtained, respectively. The ammonium nitrogen content increased significantly (140%). (author)

  1. Nickel adsorption by sodium polyacrylate-grafted activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ewecharoen, A. [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Thiravetyan, P., E-mail: paitip@hotmail.com [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Wendel, E.; Bertagnolli, H. [Institut fuer Physikalische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany)

    2009-11-15

    A novel sodium polyacrylate grafted activated carbon was produced by using gamma radiation to increase the number of functional groups on the surface. After irradiation the capacity for nickel adsorption was studied and found to have increased from 44.1 to 55.7 mg g{sup -1}. X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6 oxygen atoms at 2.04-2.06 A. It is proposed that this grafting technique could be applied to other adsorbents to increase the efficiency of metal adsorption.

  2. Voltammetric pH sensing using carbon electrodes: glassy carbon behaves similarly to EPPG.

    Science.gov (United States)

    Lu, Min; Compton, Richard G

    2014-09-21

    Developing and building on recent work based on a simple sensor for pH determination using unmodified edge plane pyrolytic graphite (EPPG) electrodes, we present a voltammetric method for pH determination using a bare unmodified glassy carbon (GC) electrode. By exploiting the pH sensitive nature of quinones present on carbon edge-plane like sites within the GC, we show how GC electrodes can be used to measure pH. The electro-reduction of surface quinone groups on the glassy carbon electrode was characterised using cyclic voltammetry (CV) and optimised with square-wave voltammetry (SWV) at 298 K and 310 K. At both temperatures, a linear correlation was observed, corresponding to a 2 electron, 2 proton Nernstian response over the aqueous pH range 1.0 to 13.1. As such, unmodified glassy carbon electrodes are seen to be pH dependent, and the Nernstian response suggests its facile use for pH sensing. Given the widespread use of glassy carbon electrodes in electroanalysis, the approach offers a method for the near-simultaneous measurement and monitoring of pH during such analyses.

  3. 40 CFR 180.1234 - Sodium carbonate; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Sodium carbonate; exemption from the... Exemptions From Tolerances § 180.1234 Sodium carbonate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sodium carbonate. [70 FR 33363...

  4. Effect of sodium bicarbonate on [HCO3-], pH, and gastrointestinal symptoms.

    Science.gov (United States)

    Carr, Amelia J; Slater, Gary J; Gore, Christopher J; Dawson, Brian; Burke, Louise M

    2011-06-01

    Sodium bicarbonate (NaHCO₃) is often ingested at a dose of 0.3 g/kg body mass (BM), but ingestion protocols are inconsistent in terms of using solution or capsules, ingestion period, combining NaHCO₃ with sodium citrate (Na₃C₆H₅O₇), and coingested food and fluid. To quantify the effect of ingesting 0.3 g/kg NaHCO₃ on blood pH, [HCO₃-], and gastrointestinal (GI) symptoms over the subsequent 3 hr using a range of ingestion protocols and, thus, to determine an optimal protocol. In a crossover design, 13 physically active subjects undertook 8 NaHCO₃ experimental ingestion protocols and 1 placebo protocol. Capillary blood was taken every 30 min and analyzed for pH and [HCO₃-]. GI symptoms were quantified every 30 min via questionnaire. Statistics used were pairwise comparisons between protocols; differences were interpreted in relation to smallest worthwhile changes for each variable. A likelihood of >75% was a substantial change. [HCO₃-] and pH were substantially greater than in placebo for all other ingestion protocols at almost all time points. When NaHCO3 was coingested with food, the greatest [HCO₃-] (30.9 mmol/kg) and pH (7.49) and lowest incidence of GI symptoms were observed. The greatest incidence of GI side effects was observed 90 min after ingestion of 0.3 g/kg NaHCO₃ solution. The changes in pH and [HCO₃-] for the 8 NaHCO₃-ingestion protocols were similar, so an optimal protocol cannot be recommended. However, the results suggest that NaHCO₃ coingested with a high-carbohydrate meal should be taken 120-150 min before exercise to induce substantial blood alkalosis and reduce GI symptoms.

  5. Laboratory-scale sodium-carbonate aggregate concrete interactions

    International Nuclear Information System (INIS)

    Westrich, H.R.; Stockman, H.W.; Suo-Anttila, A.

    1983-09-01

    A series of laboratory-scale experiments was made at 600 0 C to identify the important heat-producing chemical reactions between sodium and carbonate aggregate concretes. Reactions between sodium and carbonate aggregate were found to be responsible for the bulk of heat production in sodium-concrete tests. Exothermic reactions were initiated at 580+-30 0 C for limestone and dolostone aggregates as well as for hydrated limestone concrete, and at 540+-10 0 C for dehydrated limestone concrete, but were ill-defined for dolostone concrete. Major reaction products included CaO, MgO, Na 2 CO 3 , Na 2 O, NaOH, and elemental carbon. Sodium hydroxide, which forms when water is released from cement phases, causes slow erosion of the concrete with little heat production. The time-temperature profiles of these experiments have been modeled with a simplified version of the SLAM computer code, which has allowed derivation of chemical reaction rate coefficients

  6. A Small-Scale Capsule Test for Investigating the Sodium-Carbon Dioxide Reaction

    International Nuclear Information System (INIS)

    Kim, B. H.; Choi, J. H.; Suk, S. D.; Kim, J. M.; Choi, B. H.; Kim, B. H.; Hahn, D. H.

    2007-01-01

    The utilization of modular sodium-to-supercritical CO 2 heat exchangers may yield significant improvements for an overall plant energy utilization. The consequences of a failure of the sodium CO 2 heat exchanger boundary, however, would involve the blowdown and intermixing of high-pressure CO 2 in a sodium pool, causing a pressurization which may threaten the structural integrity of the heat exchanger. Available data seems to indicate that the chemical reaction between sodium and CO 2 would likely produce sodium oxides, sodium carbonate, carbon and carbon monoxide. Information on the kinetics of the sodium-CO 2 reaction is virtually non-existent

  7. Thermodynamics of aqueous carbonate solutions including mixtures of sodium carbonate, bicarbonate, and chloride

    Energy Technology Data Exchange (ETDEWEB)

    Peiper, J.C.; Pitzer, K.S.

    1982-01-01

    Recently the authors examined electrochemical-cell data leading to values of the activity coefficient for aqueous sodium bicarbonate. Since that preliminary analysis, new experimental measurements have been published which contribute significantly to the overall thermodynamic understanding of (sodium carbonate + sodium bicarbonate + carbonic acid). In this more extensive examination we consider a wide variety of measurements leading to activity coefficients of Na/sub 2/CO/sub 3/ and NaHCO/sub 3/ from 273 to 323 K and to relative molar enthalpies and heat capacities at 298.15 K. Tables of thermodynamic quantities at selected temperatures are included. 47 references, 2 figures, 6 tables.

  8. Separation of uranium from sodium carbonate - sodium bicarbonate eluate by ion exchange method

    International Nuclear Information System (INIS)

    Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko

    1982-01-01

    The ion exchange method was used for separating uranium from the eluate (0.5 N Na 2 CO 3 -0.5 N NaHCO 3 ) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/1 uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluant (5 % NaCl-0.5 % Na 2 CO 3 ). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased. (author)

  9. Separation of uranium from sodium carbonate-sodium bicarbonate eluate by ion exchange method

    International Nuclear Information System (INIS)

    Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko

    1982-01-01

    The ion exchange method was used for separating uranium from the eluate (0.5 N Na 2 CO 3 -0.5 N NaHCO 3 ) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/l uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluent (5% NaCl-0.5% Na 2 CO 3 ). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased. (author)

  10. Influence of the Dentinal Wall on the pH of Sodium Hypochlorite during Root Canal Irrigation

    NARCIS (Netherlands)

    Macedo, Ricardo Gomes; Herrero, Noemi Pascual; Wesselink, Paul; Versluis, Michel; van der Sluis, Luc

    Introduction: The purpose of this study was to evaluate the influence of dentin on the pH levels of different concentrations of sodium hypochlorite (NaOCl) solutions over time and to evaluate if preconditioning of dentin with 17% EDTA or agitation of the NaOCl solution influences these pH levels.

  11. Sodium bicarbonate ingestion and individual variability in time-to-peak pH.

    Science.gov (United States)

    Sparks, Andy; Williams, Emily; Robinson, Amy; Miller, Peter; Bentley, David J; Bridge, Craig; Mc Naughton, Lars R

    2017-01-01

    This study determined variability in time-to-peak pH after consumption of 300 mg kg - 1 of sodium bicarbonate. Seventeen participants (mean ± SD: age 21.38 ± 1.5 years; mass 75.8 ± 5.8 kg; height 176.8 ± 7.6 cm) reported to the laboratory where a resting capillary sample was taken. Then, 300 mg kg -1 of NaHCO 3 in 450 ml of flavoured water was ingested. Participants rested for 90 min and repeated blood samples were procured at 10 min intervals for 60 min and then every 5 min until 90 min. Blood pH concentrations were measured. Results suggested that time-to-peak pH (64.41 ± 18.78 min) was variable with a range of 10-85 min and a coefficient of variation of 29.16%. A bimodal distribution occurred, at 65 and 75 min. In conclusion, athletes, when using NaHCO 3 as an ergogenic aid, should determine their time-to-peak pH to best utilize the added buffering capacity this substance allows.

  12. Dehydration of sodium carbonate monohydrate with indirect microwave heating

    International Nuclear Information System (INIS)

    Seyrankaya, Abdullah; Ozalp, Baris

    2006-01-01

    In this study, dehydration of sodium carbonate monohydrate (Na 2 CO 3 .H 2 O) (SCM) in microwave (MW) field with silicon carbide (SiC) as an indirect heating medium was investigated. SCM samples containing up to 3% free moisture were placed in the microwave oven. The heating experiments showed that SCM is a poor microwave energy absorber for up to 6 min of irradiation at an 800 W of microwave power. The heat for SCM calcination is provided by SiC which absorbs microwave. The monohydrate is then converted to anhydrous sodium carbonate on the SiC plate by calcining, i.e. by removing the crystal water through heating of the monohydrate temperatures of over 120 deg. C. The calcination results in a solid phase recrystallization of the monohydrate into anhydrate. In the microwave irradiation process, dehydration of SCM in terms of indirect heating can be accelerated by increasing the microwave field power

  13. Leaching of uranium from Syrian phosphorite (sodium carbonate-bicarbonate)

    International Nuclear Information System (INIS)

    Abou-Jamous, J.Kh.

    1991-01-01

    The leaching of uranium from Syrian phosphorite by sodium carbonate-bicarbonate solution has been studied, using a batch technique. Parameters influencing percentage extraction of uranium that are considered and studies in this work are: Leachant concentration, particle size, heat treatment, leachant renewal, phosphorite renewal and contact time. All measurements of uranium from aqueous solutions were carried out by fluorometry. (author). 12 refs., 4 figs., 1 tab

  14. Reactions between sodium and various carbon bearing compounds

    Energy Technology Data Exchange (ETDEWEB)

    Raine, A C; Thorley, A W [UKAEA, Risley, Warrington, Cheshire (United Kingdom)

    1980-05-01

    The presence of carbon bearing materials in liquid sodium is undesirable because of their ability to carburise stainless steel components. It has been demonstrated for example that carbon taken up by stainless steels can affect their mechanical properties and that thinner sectioned material such as fuel cladding and the tubing of intermediate heat exchanger may be more sensitive to such effects. Generally speaking, there are a number of potential carbon sources in reactor systems. Some of the sources such as the graphite in neutron shield rods, boron carbide in control rods and carbide fuels are part of the reactor designs while others such as oil in mechanical pumps arid 'coupling-fluids' used to inspect plant components are associated with the respective operation arid inspection of the plant. In this paper it is intended to discuss in general terms the way these various compounds behave in liquid sodium and to assess what effect their presence will have on the materials of construction in fast reactor systems. The paper also reviews the chemistry of the environment in relation to the types of carburizing species which may exist in sodium systems.

  15. Sodium Carbonate is Saltier Than Sodium Chloride to Sodium-Depleted Rats.

    Science.gov (United States)

    St John, Steven J; McBrayer, Anya M; Krauskopf, Erin E

    2017-10-01

    In a series of behavioral experiments in the 1960s, G.R. Morrison identified several unique features of the taste of Na2CO3 to rats; namely, it is 1) considerably more intense than NaCl at isomolar concentrations, 2) avoided at 10 times lower concentrations than NaCl to thirsty rats, 3) preferred at 10 times lower concentrations than NaCl in sodium-depleted rats. He also demonstrated its qualitatively similarity to NaCl. In Experiment 1, we confirmed and extended many of Morrison's observations. Rats were injected with furosemide on 3 occasions to stimulate a sodium appetite. After each depletion, rats were given a brief-access taste test in a lickometer presenting, in random order, water and 7 concentrations of salt. One test used NaCl (0.028-0.89 M, quarter log steps), another used Na2CO3, and the third used Na2CO3, but at a tenfold lower concentration range (0.0028-0.089 M). Rats licked NaCl in an inverted-U shaped concentration-response function peaking at 0.158-0.281 M. As Morrison's results predicted, rats licked Na2CO3 in nearly identical fashion, but at a tenfold lower concentration range (peak at 0.0158-0.028 M). In a second experiment, furosemide-treated rats were repeatedly tested with the lower Na2CO3 range but mixed in the epithelial sodium channel blocker amiloride at various concentrations (3-300 μM, half log steps). Amiloride reduced licking for Na2CO3 and shifted the peak response rightward up to about half a log unit. Thus, this "super-saltiness" of Na2CO3 to rats is at least partly amiloride-dependent. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Stabilizing sodium hypochlorite at high pH: effects on soft tissue and dentin.

    Science.gov (United States)

    Jungbluth, Holger; Marending, Monika; De-Deus, Gustavo; Sener, Beatrice; Zehnder, Matthias

    2011-05-01

    When sodium hypochlorite solutions react with tissue, their pH drops and tissue sorption decreases. We studied whether stabilizing a NaOCl solution at a high pH would increase its soft-tissue dissolution capacity and effects on the dentin matrix compared with a standard NaOCl solution of the same concentration and similar initial pH. NaOCl solutions were prepared by mixing (1:1) a 10% stock solution with water (standard) or 2 mol/L NaOH (stabilized). Physiological saline and 1 mol/L NaOH served as the controls. Chlorine content and alkaline capacity of NaOCl solutions were determined. Standardized porcine palatal soft-tissue specimens and human root dentin bars were exposed to test and control solutions. Weight loss percentage was assessed in the soft-tissue dissolution assay. Three-point bending tests were performed on the root dentin bars to determine the modulus of elasticity and flexural strength. Values between groups were compared using one-way analysis of variance with the Bonferroni correction for multiple testing (α pH level of 7.5, respectively. The stabilized NaOCl dissolved significantly more soft tissue than the standard solution, and the pH remained high. It also caused a higher loss in elastic modulus and flexure strength (P < .05) than the control solutions, whereas the standard solution did not. NaOH-stabilized NaOCl solutions have a higher alkaline capacity and are thus more proteolytic than standard counterparts. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Coral calcifying fluid pH is modulated by seawater carbonate chemistry not solely seawater pH.

    Science.gov (United States)

    Comeau, S; Tambutté, E; Carpenter, R C; Edmunds, P J; Evensen, N R; Allemand, D; Ferrier-Pagès, C; Tambutté, S; Venn, A A

    2017-01-25

    Reef coral calcification depends on regulation of pH in the internal calcifying fluid (CF) in which the coral skeleton forms. However, little is known about calcifying fluid pH (pH CF ) regulation, despite its importance in determining the response of corals to ocean acidification. Here, we investigate pH CF in the coral Stylophora pistillata in seawater maintained at constant pH with manipulated carbonate chemistry to alter dissolved inorganic carbon (DIC) concentration, and therefore total alkalinity (A T ). We also investigate the intracellular pH of calcifying cells, photosynthesis, respiration and calcification rates under the same conditions. Our results show that despite constant pH in the surrounding seawater, pH CF is sensitive to shifts in carbonate chemistry associated with changes in [DIC] and [A T ], revealing that seawater pH is not the sole driver of pH CF Notably, when we synthesize our results with published data, we identify linear relationships of pH CF with the seawater [DIC]/[H + ] ratio, [A T ]/ [H + ] ratio and [[Formula: see text

  18. Effect of the coexistence of sodium caseinate and Tween 20 as stabilizers of food emulsions at acidic pH.

    Science.gov (United States)

    Perugini, Luisa; Cinelli, Giuseppe; Cofelice, Martina; Ceglie, Andrea; Lopez, Francesco; Cuomo, Francesca

    2018-02-05

    In the present investigation the properties of edible nanoemulsions were studied. Sodium caseinate represents a good candidate for food emulsion preparations thanks to its surface-active properties and because it is perceived as a natural product by consumers. Nevertheless, it is very sensitive to acidic pH close to its isoelectric point and, if used as emulsion stabilizer, this aspect can negatively affect the emulsion stability. In order to prevent this drawback, sodium caseinate was used in combination with a non-ionic surfactant (Tween 20) as emulsifier of oil/water nanoemulsions. For these reasons, nanoemulsions stabilized by Tween 20, sodium caseinate and by a blend of the two emulsifiers were studied and compared according to their response to pH variations. Nanoemulsions were characterized for size of the dispersed phase with variation of time and temperature, for their rheological properties, for surface charge as a function of pH and for protein fluorescence. Noticeably, it was ascertained that, at pH close to caseinate isoelectric point, emulsions stabilized with the blend of caseinate and Tween 20 were more stable, compared with emulsions stabilized only with sodium caseinate. Such behavior was explained according to the composition of the emulsifiers at the oil/water interface where, at acidic pH, the presence of Tween 20 ensured the steric stabilization thus improving the role of sodium caseinate as emulsion stabilizer. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Low-Dimensional Network Formation in Molten Sodium Carbonate.

    Science.gov (United States)

    Wilding, Martin C; Wilson, Mark; Alderman, Oliver L G; Benmore, Chris; Weber, J K R; Parise, John B; Tamalonis, Anthony; Skinner, Lawrie

    2016-04-15

    Molten carbonates are highly inviscid liquids characterized by low melting points and high solubility of rare earth elements and volatile molecules. An understanding of the structure and related properties of these intriguing liquids has been limited to date. We report the results of a study of molten sodium carbonate (Na2CO3) which combines high energy X-ray diffraction, containerless techniques and computer simulation to provide insight into the liquid structure. Total structure factors (F(x)(Q)) are collected on the laser-heated carbonate spheres suspended in flowing gases of varying composition in an aerodynamic levitation furnace. The respective partial structure factor contributions to F(x)(Q) are obtained by performing molecular dynamics simulations treating the carbonate anions as flexible entities. The carbonate liquid structure is found to be heavily temperature-dependent. At low temperatures a low-dimensional carbonate chain network forms, at T = 1100 K for example ~55% of the C atoms form part of a chain. The mean chain lengths decrease as temperature is increased and as the chains become shorter the rotation of the carbonate anions becomes more rapid enhancing the diffusion of Na(+) ions.

  20. Label-Free Carbon-Dots-Based Ratiometric Fluorescence pH Nanoprobes for Intracellular pH Sensing.

    Science.gov (United States)

    Shangguan, Jingfang; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Liu, Jinquan; Tang, Jinlu; Yang, Xue; Huang, Jin

    2016-08-02

    Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels.

  1. Regulation of the glutamine transporter SN1 by extracellular pH and intracellular sodium ions

    International Nuclear Information System (INIS)

    Broeer, A.; Broeer, S.; Setiawan, I.; Lang, F.

    2001-01-01

    Full text: SN1 has recently been identified as one of the major glutamine transporters in hepatocytes and brain astrocytes. It appears to be the molecular correlate of the system N amino acid transporter. Two different transport mechanisms have been proposed for this transporter. Either an electroneutral mechanism, in which glutamine uptake is coupled to an exchange of 1Na + and 1H + , or an electrogenic mechanism coupled to the exchange of 2Na + against 1H + . This study was performed to solve the discrepancies and to investigate the reversibility of the transporter. When expressed in Xenopus laevis oocytes glutamine uptake activity increased strongly with increasing pH. In agreement with the pH-dependence we found that uptake of glutamine was accompanied by an alkalization of the cytosol, indicating that SN1 mediates Glutamine/H + -Antiport. Uptake of glutamine into oocytes was Na + -dependent. Analysis of the Na + -dependence of glutamine transport and Flux studies using 22 Na + indicated that two or more sodium ions were cotransported together with glutamine. However, at the same time intracellular Na + was exchanged against extracellular Na + . Taken together with the results of the pH-dependence it is proposed that SN1 mediates a Na + /Na + -exchange and a Na + /H + -exchange, both being coupled to the transport of glutamine. In agreement with this mechanism we found that acidic pH caused a reversal of the transporter. To investigate the source of the glutamine-induced inward currents, we compared inward currents generated by the 1Na + /glutamine cotransporter ATA1 with those generated by SN1. Currents induced by glutamine uptake in SN1 expressing oocytes were only a fraction of the currents induced by glutamine in ATA1 expressing oocytes, indicating that they were not generated by a stoichiometric uptake of ions. It is concluded that SN1 is tightly regulated by pH and intracellular Na + -ions and is capable of mediating glutamine uptake and release

  2. Separation of uranium from sodium carbonate - sodium bicarbonate eluate by ion exchange method

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko (Government Industrial Research Inst., Shikoku, Takamatsu (Japan))

    1982-09-01

    The ion exchange method was used for separating uranium from the eluate (0.5 N Na/sub 2/CO/sub 3/-0.5 N NaHCO/sub 3/) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/1 uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluant (5 % NaCl-0.5 % Na/sub 2/CO/sub 3/). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased.

  3. Separation of uranium from sodium carbonate-sodium bicarbonate eluate by ion exchange method

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, K.; Hirotsu, T.; Fujii, A.; Katoh, S.; Sugasaka, K. (Government Industrial Research. Inst., Shikoku, Takamatsu (Japan))

    1982-01-01

    The ion exchange method was used for separating uranium from the eluate (0.5 N Na/sub 2/CO/sub 3/-0.5 N NaHCO/sub 3/) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/l uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluent (5% NaCl-0.5% Na/sub 2/CO/sub 3/). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased.

  4. Measurement of the activity coefficient of carbon in steels in liquid sodium

    International Nuclear Information System (INIS)

    Surville, G.

    1983-06-01

    In sodium cooled fast reactors carbon is both a carbon impurity and element of structural materials. Carbon transfert through liquid sodium can produce carburization or decarburization of structural materials. Carbon content in sodium is determined with thin foils of austenitic alloys, when equilibrium is reached thermodynamic activity of carbon in sodium is deduced from carbon activity in alloys. Studied alloys are FeMn 20%, FeNi 30%, Z2CN 18-10 and Z3CND17-13. Carbon activity of alloys in sodium was between 5.10 -3 and 10 -1 at 600 and 650 0 C. Calibration was obtained with the alloys FeNi 30% in gaseous mixtures He-CO-CO 2 of known activity [fr

  5. Pyro-oxidation of plutonium spent salts with sodium carbonate

    International Nuclear Information System (INIS)

    Bourges, G.; Godot, A.; Valot, C.; Devillard, D.

    2001-01-01

    The purification of plutonium generates spent salts, which are temporarily stored in a nuclear building. A development programme for pyrochemical treatment is in progress to stabilize and concentrate these salts in order to reduce the quantities for long-term disposal. The treatment, inspired by work previously done by LANL, consists of a pyro-oxidation of the salt with sodium carbonate to convert the actinides into oxides, then of a vacuum distillation to separate the oxides from the volatile salt matrix. Pyro-oxidation of NaCl/KCl base spent salts first produces a 'black salt' which contains more than 97% of the initial actinides. XRD analyses indicate PuO 2 as major plutonium species and sodium plutonates or plutonium sub-oxides PuO 2-x can also be identified. Next appears a 'white salt' containing less than 500 ppm of plutonium, which meets the operational criterion for LLW discard. For these salts, the pyro-oxidation process in and of itself is expected to reduce the quantities to be stored on-site by more than one-third. The pyro-oxidation of CaCl 2 /NaCl base americium extraction salts leads to oxides PuO 2 and probably AmO 2 , but the yield of concentration in the black salt is lower and the white salt cannot be discarded as LLW. During vacuum distillation, excess carbonate can dissociate and damage the efficiency of the process. Appropriate chlorine sparging at the end of the oxidation can eliminate this carbonate. (authors)

  6. Enhanced electrochemical stability of carbon-coated antimony nanoparticles with sodium alginate binder for sodium-ion batteries

    Directory of Open Access Journals (Sweden)

    Jianmin Feng

    2018-04-01

    Full Text Available The poor cycling stability of antimony during a repeated sodium ion insertion and desertion process is the key issue, which leads to an unsatisfactory application as an anode material in a sodium-ion battery. Addressed at this, we report a facile two-step method to coat antimony nanoparticles with an ultrathin carbon layer of few nanometers (denoted Sb@C NPs for sodium-ion battery anode application. This carbon layer could buffer the volume change of antimony in the charge-discharge process and improve the battery cycle performance. Meanwhile, this carbon coating could also enhance the interfacial stability by firmly connecting the sodium alginate binders through its oxygen-rich surface. Benefitted from these advantages, an improved initial discharge capacity (788.5 mA h g−1 and cycling stability capacity (553 mA h g−1 after 50 times cycle have been obtained in a battery using Sb@C NPs as anode materials at 50 mA g−1. Keywords: Sodium-ion battery, Antimony, Sodium alginate, Liquid-phase reduction, Carbon coating

  7. A Small-Scale Capsule Test for Investigating the Sodium-Carbon Dioxide Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B. H.; Choi, J. H.; Suk, S. D.; Kim, J. M.; Choi, B. H.; Kim, B. H.; Hahn, D. H

    2007-01-15

    The utilization of modular sodium-to-supercritical CO{sub 2} heat exchangers may yield significant improvements for an overall plant energy utilization. The consequences of a failure of the sodium CO{sub 2} heat exchanger boundary, however, would involve the blowdown and intermixing of high-pressure CO{sub 2} in a sodium pool, causing a pressurization which may threaten the structural integrity of the heat exchanger. Available data seems to indicate that the chemical reaction between sodium and CO{sub 2} would likely produce sodium oxides, sodium carbonate, carbon and carbon monoxide. Information on the kinetics of the sodium-CO{sub 2} reaction is virtually non-existent.

  8. Ionophore-based optical nanosensors incorporating hydrophobic carbon dots and a pH-sensitive quencher dye for sodium detection.

    Science.gov (United States)

    Galyean, A A; Behr, M R; Cash, K J

    2018-01-21

    Nanosensors present a biological monitoring method that is biocompatible, reversible, and nano-scale, and they offer many advantages over traditional organic indicators. Typical ionophore-based nanosensors incorporate nile-blue derivative pH indicators but suffer from photobleaching while quantum dot alternatives pose a potential toxicity risk. In order to address this challenge, sodium selective nanosensors containing carbon dots and a pH-sensitive quencher molecule were developed based on an ion-exchange theory and a decoupled recognition element from the pH indicator. Carbon dots were synthesized and integrated into nanosensors containing a pH-indicator, an analyte-binding ligand (ionophore), and a charge-balancing additive. These nanosensors are ion-selective against potassium (selectivity coefficient of 0.4) and lithium (selectivity coefficient of 0.9). Reversible nanosensor response to sodium is also demonstrated. The carbon dot nanosensors are resistant to changes in optical properties for at least 12 h and display stable selectivity to physiologically-relevant sodium (alpha = 0.5 of 200 mM NaCl) for a minimum of 6 days.

  9. Continuous analyzers of hydrogen and carbon in liquid sodium and of hydrocarbon total in protective atmosphere above sodium

    International Nuclear Information System (INIS)

    Pitak, O.; Fresl, M.

    1980-01-01

    The principle is described of a leak detector for detecting water penetration into sodium in a steam generator. The device operates as a diffusion H-meter with an ion pump. Ni or Fe diffusion diaphragm is washed with sodium while diffused hydrogen is pumped and also monitored with the ion pump. Another detector uses the principle of analyzing hydrocarbons in the cover gas above the sodium level. The carrier gas flow for the analyzer divided into measuring and reference parts is passed through a chamber housing the diffusion standard. For measuring carbon content in sodium, the detector analytical part may be completed with a chamber with moisturizing filling for scrubbing gas. Carbon passing through the diffusion Fe diaphragm is scrubbed on the inner wall in the form of CO which is reduced to methane and measured using the detector C-meter. (M.S.)

  10. Study of new complexes of uranium and comba radical. I.- Complexes defective in sodium carbonate

    International Nuclear Information System (INIS)

    Vera Palomino, J.; Galiano Sedano, J. A.; Parellada Bellod, R.; Bellido Gonzalez, A.

    1975-01-01

    Some complexes formed in presence of defect of sodium carbonate with respect to the stoichiometric ratio (U): (C0 3 ) = 1:3 are studied. This ratio corresponds to the main complex which is responsible for the uranium extraction with CDMBAC organic solutions and from U(VI) aqueous solutions with an excess of sodium carbonate. (Author) 10 refs

  11. Comparative solubilisation of potassium carbonate, sodium bicarbonate and sodium carbonate in hot dimethylformamide: application of cylindrical particle surface-controlled dissolution theory.

    Science.gov (United States)

    Forryan, Claire L; Compton, Richard G; Klymenko, Oleksiy V; Brennan, Colin M; Taylor, Catherine L; Lennon, Martin

    2006-02-07

    A surface-controlled dissolution of cylindrical solid particles model is applied to potassium carbonate, sodium bicarbonate and sodium carbonate in dimethylformamide at elevated temperatures. Previously published data for the dissolution of potassium carbonate is interpreted assuming a cylindrical rather than a spherical shape of the particles, the former representing a closer approximation to the true shape of the particles as revealed by scanning electron microscopy. The dissolution kinetics of sodium carbonate and sodium bicarbonate in dimethylformamide at 100 degrees C were investigated via monitoring of the deprotonation of 2-cyanophenol with dissolved solid to form the 2-cyanophenolate anion that was detected with UV-visible spectroscopy. From fitting of experimental results to theory, the dissolution rate constant, k, for the dissolutions of potassium carbonate, sodium bicarbonate and sodium carbonate in dimethylformamide at 100 degrees C were found to have the values of (1.0 +/- 0.1) x 10(-7) mol cm(-2) s(-1), (5.5 +/- 0.3) x 10(-9) mol cm(-2) s(-1) and (9.7 +/- 0.8) x 10(-9) mol cm(-2) s(-1), respectively.

  12. The effect of sodium bicarbonate oral rinse on salivary pH and oral microflora: A prospective cohort study.

    Science.gov (United States)

    Chandel, Siddhartha; Khan, Mohsin Ali; Singh, Nishi; Agrawal, Amiya; Khare, Vinita

    2017-01-01

    Present study is designed to explore the effect of sodium bicarbonate oral rinse on salivary pH and oral micro flora. Twenty five healthy subjects were recruited for the study in department of dentistry in Era Medical College. Subjects were abstained from tooth brushing overnight pre rinse (control) samples were collected after one hour of dinner and were asked to rinse with pre calibrated freshly prepared sodium bicarbonate solution. The salivary samples were then collected the following morning using sterile gauze in marked bottles. Aerobic bacterial culture was done by plating the sample directly from the swab on the surface of Blood agar and Mac Conkeys media respectively. The colony forming units and ph were calculated for the pre rinse and post rinse saliva sample. Results shows that salivary pH increased significantly after sodium Bicarbonate oral rinse. There was a marginal decrease in number of CFU/ml for bacteria especially Viridans Streptococci, Moraxella species. Sodium Bicarbonate oral rinse may be considered as a cheap and effective alternative for chlorhexidine and alcohol based mouth wash, especially where long duration usage is required.

  13. Efficient lactulose production from cheese whey using sodium carbonate.

    Science.gov (United States)

    Seo, Yeong Hwan; Park, Gwon Woo; Han, Jong-In

    2015-04-15

    An economical method of lactulose production from cheese whey was developed using sodium carbonate (Na2CO3). Three parameters such as temperature, reaction time, and Na2CO3 concentration were identified as experimental factors, and yield was selected as a response parameter. The experimental factors were optimised employing Response Surface Methodology (RSM). Maximum yield of 29.6% was obtained at reaction time of 20.41 min, Na2CO3 of 0.51% at 90 °C. To overcome this limited lactulose yield, due to the conversion of lactulose to galactose, fed batch system was applied using dried cheese whey as lactose source. By this system, limit was broken, and 15.8 g/L of lactulose is produced in hour. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Application of a commercial diffusion type carbon meter in a sodium circuit

    International Nuclear Information System (INIS)

    Bhat, N.P.; Borgstedt, H.U.; Peric, Z.; Witting, G.

    1980-01-01

    The exchange of carbon between structural materials and liquid sodium influences the mechanical properties of components of the cooling circuits. Therefore, the estimation of the carbon content of the alkali metal and the knowledge of its carburizing potential is of importance. Since some years the measurement of the carburizing potential of sodium is easy to perform by the application of the foil equilibration method which leads to good results in spite of the very low carbon concentrations in the liquid metal. Thin foils (0.025 to 0.125 mm) of Fe-18Cr-8Ni-C alloy (corresponding to stainless steel type AISI 304) are immersed in sodium at 550 to 700 deg. C for 200 to 400 hours. The equilibrium of the carbon distribution must be reached. Chemical analyses of the steel tabs and relation of concentration to activity of carbon lead to information on the carbon concentration in the sodium, if the saturation concentration of carbon in sodium is known. The method gives arbitrary values over a longer period of time. The time needed for equilibration and analysis causes a delay for the getting of results. Therefore, there is a need for instruments which are capable to measure carbon directly in the circuits and give continuously information on the actual carbon activities in the fluid. Until 1975 only one carbon meter was commercially available. One unit in was tested a chemical analytical sodium circuit

  15. The effect of variations in carbon activity on the carburization of austenitic steels in sodium

    International Nuclear Information System (INIS)

    Gwyther, J.R.; Hobdell, M.R.; Hooper, A.J.

    1978-07-01

    Experience has shown that the liquid sodium coolant of fast breeder reactors is an effective carbon-transport medium; the resulting carburization of thin austenitic stainless steel components (eg IHX and fuel cladding) could adversely affect their mechanical integrity. The degree and nature of steel carburization depend, inter alia, on the carbon activity of the sodium environment. Exploratory tests are described in which specimens of austenitic stainless steel were carburized in sodium, the carbon activity of which was continuously monitored by a BNL electrochemical carbon meter. The sodium carbon activity was initially high, but decreased with time, simulating conditions equivalent to plant start-up or coolant clean-up following accidental oil ingress. The extent and nature of steel carburization was identified by metallography, electron microscopy, X-ray crystallography and chemical analysis. (author)

  16. Sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured rat caput epididymal epithelium.

    Science.gov (United States)

    Zuo, Wu-Lin; Li, Sheng; Huang, Jie-Hong; Yang, Deng-Liang; Zhang, Geng; Chen, Si-Liang; Ruan, Ye-Chun; Ye, Ke-Nan; Cheng, Christopher H K; Zhou, Wen-Liang

    2011-01-01

    The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na(+)/HCO(3)(-) cotransporter in the pH regulation in rat epididymis. Immunofluorescence staining of pan cytokeratin in the primary culture of rat caput epididymal epithelium showed that the system was a suitable model for investigating the function of epididymal epithelium. Intracellular and apical pH were measured using the fluorescent pH sensitive probe carboxy-seminaphthorhodafluor-4F acetoxymethyl ester (SNARF-4F) and sparklet pH electrode respectively to explore the functional role of rat epididymal epithelium. In the HEPES buffered Krebs-Henseleit (KH) solution, the intracellular pH (pHi) recovery from NH(4)Cl induced acidification in the cultured caput epididymal epithelium was completely inhibited by amiloride, the inhibitor of Na(+)/H(+) exchanger (NHE). Immediately changing of the KH solution from HEPES buffered to HCO(3)(-) buffered would cause another pHi recovery. The pHi recovery in HCO(3)(-) buffered KH solution was inhibited by 4, 4diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), the inhibitor of HCO(3)(-) transporter or by removal of extracellular Na(+). The extracellular pH measurement showed that the apical pH would increase when adding DIDS to the apical side of epididymal epithelial monolayer, however adding DIDS to the basolateral side had no effect on apical pH. The present study shows that sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured caput epididymal epithelium.

  17. Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage.

    Science.gov (United States)

    Johanningsmeier, Suzanne D; Franco, Wendy; Perez-Diaz, Ilenys; McFeeters, Roger F

    2012-07-01

    Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial instability. Objectives of this study were to determine the combined effects of NaCl and pH on fermented cucumber spoilage and to determine the ability of lactic acid bacteria (LAB) spoilage isolates to initiate lactic acid degradation in fermented cucumbers. Cucumbers fermented with 0%, 2%, 4%, and 6% NaCl were blended into slurries (FCS) and adjusted to pH 3.2, 3.8, 4.3, and 5.0 prior to centrifugation, sterile-filtration, and inoculation with spoilage organisms. Organic acids and pH were measured initially and after 3 wk, 2, 6, 12, and 18 mo anaerobic incubation at 25 °C. Anaerobic lactic acid degradation occurred in FCS at pH 3.8, 4.3, and 5.0 regardless of NaCl concentration. At pH 3.2, reduced NaCl concentrations resulted in increased susceptibility to spoilage, indicating that the pH limit for lactic acid utilization in reduced NaCl fermented cucumbers is 3.2 or lower. Over 18 mo incubation, only cucumbers fermented with 6% NaCl to pH 3.2 prevented anaerobic lactic acid degradation by spoilage bacteria. Among several LAB species isolated from fermented cucumber spoilage, Lactobacillus buchneri was unique in its ability to metabolize lactic acid in FCS with concurrent increases in acetic acid and 1,2-propanediol. Therefore, L. buchneri may be one of multiple organisms that contribute to development of fermented cucumber spoilage. Microbial spoilage of fermented cucumbers during bulk storage causes economic losses for producers. Current knowledge is insufficient to predict or control these losses. This study demonstrated that in the absence of oxygen, cucumbers fermented with 6% sodium chloride to pH 3.2 were not subject to spoilage. However, lactic acid was degraded

  18. Sodium

    Science.gov (United States)

    Table salt is a combination of two minerals - sodium and chloride Your body needs some sodium to work properly. It helps with the function ... in your body. Your kidneys control how much sodium is in your body. If you have too ...

  19. Evaluation of sodium carbonate peroxyhydrate as a potential catfish egg disinfectant.

    Science.gov (United States)

    Small, Brian C

    2009-06-01

    Two experiments were conducted to evaluate the efficacy of sodium carbonate peroxyhydrate (SCP) in improving the hatching success of channel catfish Ictalurus punctatus when used as a prophylactic chemotherapeutant during egg incubation. In the first experiment, the efficacy of SCP was evaluated in 379-L aluminum incubation troughs similar to those used in commercial hatcheries. Egg masses treated daily with 254 mg of SCP/L of water had significantly higher mean hatching success than untreated controls, and a pathogen-inhibiting effect was also evident (i.e., no gross infection was observed on the treated egg masses). In the second experiment, the hatching success of egg masses treated daily with 254 mg/L was compared with that of egg masses treated daily with hydrogen peroxide (70 mg/L). The effects of both treatments on the pH, dissolved oxygen, and hydrogen peroxide concentrations in the trough were also examined. Both SCP and hydrogen peroxide significantly improved hatching success. Unlike in the treatment with hydrogen peroxide, water pH increased during the treatment with SCP; however, no negative effects on hatching success were observed. The results of this research suggest that SCP acts similarly to hydrogen peroxide in improving channel catfish hatching success and warrants further research to determine whether it could be a practical and effective alternative for managing catfish egg infections in commercial hatcheries.

  20. Thermal Decomposition of Sodium Hydrogen Carbonate and Textural Features of Its Calcines

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Pohořelý, Michael; Šyc, Michal

    2013-01-01

    Roč. 52, č. 31 (2013), s. 10619-10626 ISSN 0888-5885 R&D Projects: GA MŠk(CZ) 7C11009 Grant - others:RFCS(XE) RFCR-CT-2010-00009 Institutional support: RVO:67985858 Keywords : thermal decomposition * sodium hydrogen carbonate * sodium bicarbonate Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.235, year: 2013

  1. Design and test of a vacuum distillation method for determining carbon in sodium

    International Nuclear Information System (INIS)

    Irmisch, R.; Rettig, D.; Woelke, K.

    1976-08-01

    A method is described for determining total and carbonate carbon in sodium samples until 10 g. Sodium is removed by vacuum distillation at 300 0 C and the carbon in the residue is converted to carbon dioxide by combustion in a stream of air or thermic splitting in a stream of cover gas at 1000 0 C. The carbon dioxide is measured manometrically. It is therefore not necessary to carry out calibration. Distillation and combustion rig are combined with inertgas filled transfer box. Therefore the sodium sample does not get into touch with air. Test of this method was carried out with Na 2 CO 3 and WC. Carbon recoveries were for Na 2 CO 3 between 103 and 107% and for WC between 92 and 96%. The blank value found being 9 μg C and sensitivity 3 μg C. (author)

  2. Modeling the Combined Effects of Temperature, pH, and Sodium Chloride and Sodium Lactate Concentrations on the Growth Rate of Lactobacillus plantarum ATCC 8014

    Directory of Open Access Journals (Sweden)

    Francieli Dalcanton

    2018-01-01

    Full Text Available Nowadays, microorganisms with probiotic or antimicrobial properties are receiving major attention as alternative resources for food preservation. Lactic acid bacteria are able to synthetize compounds with antimicrobial activity against pathogenic and spoilage flora. Among them, Lactobacillus plantarum ATCC 8014 has exhibited this capacity, and further studies reveal that the microorganism is able to produce bacteriocins. An assessment of the growth of L. plantarum ATCC 8014 at different conditions becomes crucial to predict its development in foods. A response surface model of the growth rate of L. plantarum was built in this study as a function of temperature (4, 7, 10, 13, and 16°C, pH (5.5, 6.0, 6.5, 7.0, and 7.5, and sodium chloride (0, 1.5, 3.0, 4.5, and 6.0% and sodium lactate (0, 1, 2, 3, and 4% concentrations. All the factors were statistically significant at a confidence level of 90%  (p<0.10. When temperature and pH increased, there was a corresponding increase in the growth rate, while a negative relationship was observed between NaCl and Na-lactate concentrations and the growth parameter. A mathematical validation was carried out with additional conditions, demonstrating an excellent performance of the model. The developed model could be useful for designing foods with L. plantarum ATCC 8014 added as a probiotic.

  3. Factors Affecting Dissolution Resistance of AC Anodizing Al in Sodium Carbonate Solution

    International Nuclear Information System (INIS)

    Abou-Krisha, M.

    2001-01-01

    Studies were performed to determine the effect of different factors on the properties and so the dissolution resistance of the anodic film of Al. Conductance and thermometric measurements were applied to evaluate the dissolution rate. The effect of applied AC voltage concentration of sodium carbonate solution, the anodization time and the temperature of sodium carbonate solutions show a parallel increase in the dissolution resistance of studied Al in hydrochloride acid. The results show that films formed by sodium carbonate solution were of porous type and have pronounced high resistance. Scanning electron microscope and x-ray diffraction further examined the films. The anodic and cathodic behavior and the effect of the scanning rate on the polarization of Al in sodium carbonate solution were studied. The regression analysis was applied to all results. (Author)

  4. Solubility of ammonium metavanadate in ammonium carbonate and sodium bicarbonate solutions at 25 deg C

    International Nuclear Information System (INIS)

    Fedorov, P.I.; Andreev, V.K.; Slotvinskij-Sidak, N.P.

    1978-01-01

    Solubility at 25 deg C has been studied in the system ammonium metavanadate - sodium bicarbonate - water which is a stable section of the corresponding quaternary mutual system. In the eutonic point the content of ammonium metavanadate is 4.95% and of sodium bicarbonate 12.1%. The crystallization branch of ammonium metavanadate has been studied in the system ammonium metavanadate - ammonium carbonate - water at 25 deg C. Metavanadate solubility attains minimum (0.14%) at ammonium carbonate concentration 2.6%. Three sections have been studied of the quaternary system ammonium - metavanadate - ammonium carbonate - sodium bicarbonate-water at 25 deg C in the crystallization region of ammonium metavanadate at a ratio of sodium bicarbonate to ammonium carbonate 3:1, 1:1, and 1:3. A region of minimum solubility of ammonium metavanadate has been detected (0.1%)

  5. Sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured rat caput epididymal epithelium.

    Directory of Open Access Journals (Sweden)

    Wu-Lin Zuo

    Full Text Available The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na(+/HCO(3(- cotransporter in the pH regulation in rat epididymis.Immunofluorescence staining of pan cytokeratin in the primary culture of rat caput epididymal epithelium showed that the system was a suitable model for investigating the function of epididymal epithelium. Intracellular and apical pH were measured using the fluorescent pH sensitive probe carboxy-seminaphthorhodafluor-4F acetoxymethyl ester (SNARF-4F and sparklet pH electrode respectively to explore the functional role of rat epididymal epithelium. In the HEPES buffered Krebs-Henseleit (KH solution, the intracellular pH (pHi recovery from NH(4Cl induced acidification in the cultured caput epididymal epithelium was completely inhibited by amiloride, the inhibitor of Na(+/H(+ exchanger (NHE. Immediately changing of the KH solution from HEPES buffered to HCO(3(- buffered would cause another pHi recovery. The pHi recovery in HCO(3(- buffered KH solution was inhibited by 4, 4diisothiocyanatostilbene-2,2-disulfonic acid (DIDS, the inhibitor of HCO(3(- transporter or by removal of extracellular Na(+. The extracellular pH measurement showed that the apical pH would increase when adding DIDS to the apical side of epididymal epithelial monolayer, however adding DIDS to the basolateral side had no effect on apical pH.The present study shows that sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured caput epididymal epithelium.

  6. Ultrasonic Assisted Synthesis of Chromenes Catalyzed by Sodium Carbonate in Aqueous Media.

    Science.gov (United States)

    Sabbaghan, Maryam; Sofalgar, Pegah

    2015-01-01

    A simple, efficient, and environmentally benign procedure for the synthesis of 2-amino-4H-chromene ring has been achieved by the three-component reaction of an aromatic aldehyde, malononitrile and diverse enolizable C-H activated compound under ultrasound irradiation using sodium carbonate as a catalyst in aqueous media. Sodium carbonate as a natural salt, being available as an inexpensive catalyst combined with ultrasound method promoted this protocol in comparison to other methods and catalysts.

  7. Geographic distribution of soluble salts, exchangeable sodium and calcium carbonate in the Caribbean Region of Colombia

    International Nuclear Information System (INIS)

    Pulido, Carlos E

    2000-01-01

    A research was carried out to establish the distribution of soluble salts, exchangeable sodium and calcium carbonate in the soils of the Caribbean Region. The results show that 28,3% (3.506.033 ha) of the soils have problems related to salinity. The soils of the arid and semiarid zones and those belonging to the sea plain are affected severely by soluble salts, exchangeable sodium and calcium carbonate

  8. Preliminary Plugging tests in Narrow Sodium Channels by Sodium and Carbon Dioxide reaction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    This report is on the investigation of the physical/chemical phenomena that a slow loss of CO{sub 2} inventory into sodium after the sodium-CO{sub 2} boundary failure in PCHEs in realistic operating conditions. The first phenomenon is potential channel plugging inside the narrow PCHE channel. Unlike a conventional shell and- tube type HXs, failures in a PCHE are expected to be small cracks. If the faulted channel is blocked, it may have a positive function for plant safety because the pressure boundary would automatically recover due to this self-plugging. The other one is damage propagation on pressure boundary, which is referred to as potential wastage with combined corrosion/erosion effect. Physical/chemical phenomena that a slow loss of CO{sub 2} inventory into sodium after the sodium-CO{sub 2} boundary failure in printed circuit heat exchangers (PCHEs) were investigated. Our preliminary experimental results of plugging show that sodium flow immediately stopped as CO{sub 2} was injected through the nozzle at 300-400 .deg. C in 3 mm sodium channels, whereas sodium flow stopped about 60 min after CO{sub 2} injection in 5 mm sodium channels.

  9. Investigation of Plugging of Narrow Sodium Channels by Sodium and Carbon Dioxide Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong; Kim, Tae-joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The supercritical CO{sub 2} Brayton cycle system is known to be a promising power conversion system for improving the efficiency and preventing the sodium water reaction (SWR) of the current SFR concept using a Rankine steam cycle. PCHEs are known to have potential for reducing the volume occupied by the sodium-to-CO{sub 2} exchangers as well as the heat exchanger mass relative to traditional shell-and-tube heat exchangers. Here, we report a study on a plugging test by the interaction of sodium and CO{sub 2} to investigate design parameters of sodium channels in the realistic operating conditions. We investigated a plugging test by an interaction of sodium and CO{sub 2} with different cross sectional areas of the sodium channels. It was found that the flow rate of sodium decreased earlier and faster with a narrower cross sectional area compared to a wider one. Our experimental results are expected to be used for determining the sodium channel areas of PCHEs.

  10. The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

    Science.gov (United States)

    Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

    2018-01-01

    Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

  11. Effect of Solution pH on the Adsorption of Paracetamol on Chemically Modified Activated Carbons

    Directory of Open Access Journals (Sweden)

    Valentina Bernal

    2017-06-01

    Full Text Available Paracetamol adsorption in acidic, neutral and basic media on three activated carbons with different chemistry surfaces was studied. A granular activated carbon (GAC was prepared from coconut shell; starting from this sample, an oxidized activated carbon (GACo was obtained by treating the GAC with a boiling solution of 6 M nitric acid, so to generate a greater number of oxygenated surface groups. In addition, a reduced activated carbon (GACr was obtained by heating the GAC at 1173 K, to remove the oxygenated surface groups. Paracetamol adsorption was higher for GACr due to the lower presence of oxygenated surface functional groups. Moreover, adsorption was highest at neutral pH. The magnitude of the interactions between paracetamol molecules and activated carbons was studied by measuring the immersion enthalpies of activated carbons in solution of paracetamol at different concentrations and pH values and by calculating the interaction enthalpy. The highest value was obtained for GACr in a paracetamol solution of 1000 mg L−1 at pH 7, confirming that paracetamol adsorption is favoured on basic activated carbons at pH values near to neutrality. Finally, the Gibbs energy changes confirmed the latter result, allowing explaining the different magnitudes of the interactions between paracetamol and activated carbons, as a function of solution pH.

  12. Fluoroethylene Carbonate-Based Electrolyte with 1 M Sodium Bis(fluorosulfonyl)imide Enables High-Performance Sodium Metal Electrodes.

    Science.gov (United States)

    Lee, Yongwon; Lee, Jaegi; Lee, Jeongmin; Kim, Koeun; Cha, Aming; Kang, Sujin; Wi, Taeung; Kang, Seok Ju; Lee, Hyun-Wook; Choi, Nam-Soon

    2018-05-02

    Sodium (Na) metal anodes with stable electrochemical cycling have attracted widespread attention because of their highest specific capacity and lowest potential among anode materials for Na batteries. The main challenges associated with Na metal anodes are dendritic formation and the low density of deposited Na during electrochemical plating. Here, we demonstrate a fluoroethylene carbonate (FEC)-based electrolyte with 1 M sodium bis(fluorosulfonyl)imide (NaFSI) salt for the stable and dense deposition of the Na metal during electrochemical cycling. The novel electrolyte combination developed here circumvents the dendritic Na deposition that is one of the primary concerns for battery safety and constructs the uniform ionic interlayer achieving highly reversible Na plating/stripping reactions. The FEC-NaFSI constructs the mechanically strong and ion-permeable interlayer containing NaF and ionic compounds such as Na 2 CO 3 and sodium alkylcarbonates.

  13. Effect of pH on structure, function, and stability of mitochondrial carbonic anhydrase VA.

    Science.gov (United States)

    Idrees, Danish; Shahbaaz, Mohd; Bisetty, Krishna; Islam, Asimul; Ahmad, Faizan; Hassan, Md Imtaiyaz

    2017-02-01

    Mitochondrial carbonic anhydrase VA (CAVA) catalyzes the hydration of carbon dioxide to produce proton and bicarbonate which is primarily expressed in the mitochondrial matrix of liver, and involved in numerous physiological processes including lipogenesis, insulin secretion from pancreatic cells, ureagenesis, gluconeogenesis, and neuronal transmission. To understand the effect of pH on the structure, function, and stability of CAVA, we employed spectroscopic techniques such as circular dichroism, fluorescence, and absorbance measurements in wide range of pH (from pH 2.0 to pH 11.5). CAVA showed an aggregation at acidic pH range from pH 2.0 to pH 5.0. However, it remains stable and maintains its secondary structure in the pH range, pH 7.0-pH 11.5. Furthermore, this enzyme has an appreciable activity at more than pH 7.0 (7.0 < pH ≤ 11.5) with maximum activity at pH 9.0. The maximal values of k cat and k cat /K m at pH 9.0 are 3.7 × 10 6  s -1 and 5.5 × 10 7  M -1  s -1 , respectively. However, this enzyme loses its activity in the acidic pH range. We further performed 20-ns molecular dynamics simulation of CAVA to see the dynamics at different pH values. An excellent agreement was observed between in silico and in vitro studies. This study provides an insight into the activity of CAVA in the pH range of subcellular environment.

  14. Carbon in sodium - A status review of the U.S.A. R and D work

    International Nuclear Information System (INIS)

    McCown, J.J.; Bagnall, C.

    1980-01-01

    Liquid Metal Fast Breeder Reactors contain several types of steel in primary and secondary sodium systems. Austenitic stainless steels are used for in-core components, valves, heat exchangers, tanks and fuel cladding in primary systems. In power generating plants, the secondary or intermediate heat transport system may contain both austenitic and ferritic steel such as 2-1/4 Cr-l Mo type. Sodium circulating throughout the plant contains a number of impurities, metallic and non-metallic, with the steel interstitial elements carbon, hydrogen and oxygen being of prime importance. These elements can affect corrosion rates and mechanical behavior of materials. In the case of carbon, the sodium provides a transport medium with carburization and decarburization occurring in several parts of a system at rates depending upon temperature and types of steel. The US Sodium Technology R and D programs have investigated the behavior, transport, measurement and control of carbon in sodium. Measurement and control methods for carbon-containing materials which might contaminate the plant systems during reactor operation have also been studied. During the early 1970's, several US laboratories were active in studying carbon solubility, activity in sodium and interstitial transfer using both theoretical and experimental approaches. Modelling studies were done and models were used to predict FFTF and CRBRP materials requirements, component design and plant operating conditions. Over the past several years, carbon work has not been heavily emphasized. Most of the R and D studies have centered on improving chemical analysis methods for measuring active carbon, both by on-line monitors and by metal foil equilibration procedures; and on studies of pump oil-sodium reactions, reaction products, temperature effects and oil leak detection methods. One program at General Electric is investigating carburization-decarburization in a ferritic-austenitic system simulating conditions expected in

  15. Carbon in sodium - A status review of the U.S.A. R and D work

    Energy Technology Data Exchange (ETDEWEB)

    McCown, J J; Bagnall, C [HEDL, Richland, WA (United States)

    1980-05-01

    Liquid Metal Fast Breeder Reactors contain several types of steel in primary and secondary sodium systems. Austenitic stainless steels are used for in-core components, valves, heat exchangers, tanks and fuel cladding in primary systems. In power generating plants, the secondary or intermediate heat transport system may contain both austenitic and ferritic steel such as 2-1/4 Cr-l Mo type. Sodium circulating throughout the plant contains a number of impurities, metallic and non-metallic, with the steel interstitial elements carbon, hydrogen and oxygen being of prime importance. These elements can affect corrosion rates and mechanical behavior of materials. In the case of carbon, the sodium provides a transport medium with carburization and decarburization occurring in several parts of a system at rates depending upon temperature and types of steel. The US Sodium Technology R and D programs have investigated the behavior, transport, measurement and control of carbon in sodium. Measurement and control methods for carbon-containing materials which might contaminate the plant systems during reactor operation have also been studied. During the early 1970's, several US laboratories were active in studying carbon solubility, activity in sodium and interstitial transfer using both theoretical and experimental approaches. Modelling studies were done and models were used to predict FFTF and CRBRP materials requirements, component design and plant operating conditions. Over the past several years, carbon work has not been heavily emphasized. Most of the R and D studies have centered on improving chemical analysis methods for measuring active carbon, both by on-line monitors and by metal foil equilibration procedures; and on studies of pump oil-sodium reactions, reaction products, temperature effects and oil leak detection methods. One program at General Electric is investigating carburization-decarburization in a ferritic-austenitic system simulating conditions expected in

  16. Binding of sodium dodecyl sulfate with linear and branched polyethyleneimines in aqueous solution at different pH values.

    Science.gov (United States)

    Wang, Hao; Wang, Yilin; Yan, Haike; Zhang, Jin; Thomas, Robert K

    2006-02-14

    Isothermal titration microcalorimetry (ITC), conductivity, and turbidity measurements have been carried out to study the interaction of sodium dodecyl sulfate (SDS) with polyethyleneimines (PEI) including linear PEI and branched PEI at different pH values of 3, 7, and 10. In all cases, the polymers show a remarkable affinity toward SDS. At pH 3, the polymer PEI is a strong polycation, and the binding is dominated by electrostatic 1:1 charge neutralization with the anionic surfactant. At pH 7, the electrostatic attraction between SDS and PEI is weak, and the hydrophobic interaction becomes stronger. At the natural pH of 10, PEI is essentially nonionic and binds SDS in the form of polymer-bound surfactant aggregates. The charge neutralization concentration (C1) of SDS for the PEI-SDS complex can be derived from the curves of variation of the enthalpy, conductivity, and turbidity with SDS concentration. There is good agreement between the results from the three methods and all show a decrease with increasing pH. The total interaction enthalpies (deltaH(total)) of PEI with SDS are obtained from the observed enthalpy curves and the difference enthalpy (deltaH*) between the total enthalpy of branched PEI with SDS, and the total enthalpy of linear PEI with SDS can be derived from the obtained deltaH(total). The difference deltaH* increases dramatically as pH increases, which indicates that the interactions are different for linear PEI and branched PEI at high pH values. A schematic map of the different states of aggregation is presented.

  17. Chemical modification of chitosan in the absence of solvent for diclofenac sodium removal: pH and kinetics studies

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Kerlaine Alexandre Araujo; Osorio, Luizangela Reis; Silva, Marcos Pereira; Silva Filho, Edson Cavalcanti da, E-mail: edsonfilho@ufpi.edu.br [Universidade Federal do Piaui (UFPI/CCN), Teresina, PI (Brazil). Centro de Ciencias da Natureza. Lab. Interdisciplinar de Materiais Avancados; Sousa, Kaline Soares [Universidade Federal da Paraiba (UFPB/CCEN), Joao Pessoa, PB (Brazil). Centro de Ciencias Exatas e da Natureza. Dept. de Quimica

    2014-08-15

    Chitosan was modified with acetylacetone and ethylenediamine in the absence of solvent. The new biopolymer obtained from the modification was characterized by elemental analysis and NMR 13C and applied in the removal of diclofenac sodium aqueous solution varying the pH and time. Through elemental analysis was possible to verify a decreasing in C/N relation after reaction with acetylacetone and an increasing after modification with ethylenediamine. From NMR analysis was verified the appearance of peaks around 160-210 ppm in both materials due to free carbonyl groups in the first step of the modification, besides the formation of imine bonds. The adsorption tests showed that the highest value occurred at pH 4 and from the results of the kinetic study was found that maximum adsorption occurred within 45 minutes and experimental data adjusted better to linear adjustment, following pseudo second-order model. The results show a material efficient in the removal of emerging pollutants. (author)

  18. Metal corrosion in a supercritical carbon dioxide - liquid sodium power cycle.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Conboy, Thomas M.

    2012-02-01

    A liquid sodium cooled fast reactor coupled to a supercritical carbon dioxide Brayton power cycle is a promising combination for the next generation nuclear power production process. For optimum efficiency, a microchannel heat exchanger, constructed by diffusion bonding, can be used for heat transfer from the liquid sodium reactor coolant to the supercritical carbon dioxide. In this work, we have reviewed the literature on corrosion of metals in liquid sodium and carbon dioxide. The main conclusions are (1) pure, dry CO{sub 2} is virtually inert but can be highly corrosive in the presence of even ppm concentrations of water, (2) carburization and decarburization are very significant mechanism for corrosion in liquid sodium especially at high temperature and the mechanism is not well understood, and (3) very little information could be located on corrosion of diffusion bonded metals. Significantly more research is needed in all of these areas.

  19. Na-ion capacitor using sodium pre-doped hard carbon and activated carbon

    International Nuclear Information System (INIS)

    Kuratani, Kentaro; Yao, Masaru; Senoh, Hiroshi; Takeichi, Nobuhiko; Sakai, Tetsuo; Kiyobayashi, Tetsu

    2012-01-01

    We assembled a sodium-ion capacitor (Na-IC) by combining sodium pre-doped hard carbon (HC) as the negative- and activated carbon (AC) as the positive-electrode. The electrochemical properties were compared with two lithium-ion capacitors (Li-ICs) in which the negative electrodes were prepared with Li pre-doped HC and mesocarbon microbeads (MCMB). The positive and negative electrodes were prepared using the established doctor blade method. The negative electrodes were galvanostatically pre-doped with Na or Li to 80% of the full capacity of carbons. The potential of the negative electrodes after pre-doping was around 0.0 V vs. Na/Na + or Li/Li + , which resulted in the higher output potential difference of the Na-IC and Li-ICs than that of the conventional electrochemical double-layer capacitors (EDLCs) because AC positive electrode works in the same principle both in the ion capacitors and in the EDLC. The state-of-charge of the negative electrode varied 80 ± 10% during the electrochemical charging and discharging. The capacity of the cell was evaluated using galvanostatic charge–discharge measurement. At the discharge current density of 10 mA cm −2 , the Na-IC maintained 70% of the capacity that obtained at the current density of 0.5 mA cm −2 , which was comparable to the Li-ICs. At 50 mA cm −2 , the capacities of the Li-IC(MCMB) and the Na-IC dropped to 20% whereas the Li-IC(HC) retained 30% of the capacity observed at 0.5 mA cm −2 . The capacities of the Na-IC and Li-ICs decreased by 9% and 3%, respectively, after 1000 cycles of charging and discharging.

  20. Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

    Science.gov (United States)

    Geer, Tyler D; Kinley, Ciera M; Iwinski, Kyla J; Calomeni, Alyssa J; Rodgers, John H

    2016-10-01

    Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the

  1. A computational model for the carbon transfer in stainless steel sodium systems

    International Nuclear Information System (INIS)

    Casadio, S.; Scibona, G.

    1980-01-01

    A method is proposed of computing the carbon transfer in the type 316, 304 and 321 stainless steels in sodium environment as a function of temperature, exposure time and carbon concentration in the sodium. The method is based on the criteria developed at ANL by introducing some simplifications and takes also into account the correlations obtained at WARD. Calculated carbon profiles are compared both with experimental data and with the results available by the other computer methods. The limits for quantitative predictions of the stainless steel carburization or decarburization exposed in a specific environment are discussed. (author)

  2. Crystal growth of calcium carbonate in silk fibroin/sodium alginate hydrogel

    Science.gov (United States)

    Ming, Jinfa; Zuo, Baoqi

    2014-01-01

    As known, silk fibroin-like protein plays a pivotal role during the formation of calcium carbonate (CaCO3) crystals in the nacre sheets. Here, we have prepared silk fibroin/sodium alginate nanofiber hydrogels to serve as templates for calcium carbonate mineralization. In this experiment, we report an interesting finding of calcium carbonate crystal growth in the silk fibroin/sodium alginate nanofiber hydrogels by the vapor diffusion method. The experimental results indicate calcium carbonate crystals obtained from nanofiber hydrogels with different proportions of silk fibroin/sodium alginate are mixture of calcite and vaterite with unusual morphologies. Time-dependent growth study was carried out to investigate the crystallization process. It is believed that nanofiber hydrogels play an important role in the process of crystallization. This study would help in understanding the function of organic polymers in natural mineralization, and provide a novel pathway in the design and synthesis of new materials related unique morphology and structure.

  3. Experimental Precipitation of Carbonate Minerals: Effect of pH, Supersaturation and Substrate

    OpenAIRE

    Tetteh, Abednego

    2012-01-01

    Understanding the controlling factors and elucidating the requirements and conditions necessary for carbon dioxide (CO2) storage by mineral trapping (or carbonation) is of paramount interest for any technical application as a means for carbon dioxide capture and storage (CCS). The effect of pH, supersaturation and substrate has been studied using non-stirred batch reactors at initial constant temperature of 150 oC. These conditions are relevant for mineral trapping. A set of experiments was c...

  4. Enhanced Lithium- and Sodium-Ion Storage in an Interconnected Carbon Network Comprising Electronegative Fluorine.

    Science.gov (United States)

    Hong, Seok-Min; Etacheri, Vinodkumar; Hong, Chulgi Nathan; Choi, Seung Wan; Lee, Ki Bong; Pol, Vilas G

    2017-06-07

    Fluorocarbon (C x F y ) anode materials were developed for lithium- and sodium-ion batteries through a facile one-step carbonization of a single precursor, polyvinylidene fluoride (PVDF). Interconnected carbon network structures were produced with doped fluorine in high-temperature carbonization at 500-800 °C. The fluorocarbon anodes derived from the PVDF precursor showed higher reversible discharge capacities of 735 mAh g -1 and 269 mAh g -1 in lithium- and sodium-ion batteries, respectively, compared to the commercial graphitic carbon. After 100 charge/discharge cycles, the fluorocarbon showed retentions of 91.3% and 97.5% in lithium (at 1C) and sodium (at 200 mA g -1 ) intercalation systems, respectively. The effects of carbonization temperature on the electrochemical properties of alkali metal ion storage were thoroughly investigated and documented. The specific capacities in lithium- and sodium-ion batteries were dependent on the fluorine content, indicating that the highly electronegative fluorine facilitates the insertion/extraction of lithium and sodium ions in rechargeable batteries.

  5. Effect of Sodium Chloride and pH on Enterotoxin C Production

    Science.gov (United States)

    Genigeorgis, Constantin; Foda, Mohamed S.; Mantis, Antony; Sadler, Walter W.

    1971-01-01

    Growth and production of enterotoxin C by Staphylococcus aureus strain 137 in 3% + 3% protein hydrolysate powder N-Z Amine NAK broths with 0 to 12% NaCl and an initial pH of 4.00 to 9.83 were studied during an 8-day incubation period at 37 C. Growth was initiated at pH values as low as 4.00 and as high as 9.83 at 0% salt level as long as the inoculum contained at least 108 cells per ml. Rate of growth decreased as the NaCl concentration was increased gradually to 12%. Enterotoxin C was produced in broths inoculated with 108 cells per ml and above and having initial pH ranges of 4.00 to 9.83, 4.40 to 9.43, 4.50 to 8.55 and respective NaCl concentrations of 0, 4, and 8%. In the presence of 10% NaCl, the pH range supporting enterotoxin C production was 5.45 to 7.30 for an inoculum level of 108 cells per ml and 6.38 to 7.30 for 3.6 × 106 cells per ml. In repeated experiments in which the inoculum contained 108 cells per ml, we failed to demonstrate enterotoxin C production in broths with 12% NaCl and a pH range of 4.50 to 8.55 and concentrated up to 14 times. The effect of NaCl on enterotoxin C production followed the same pattern as its effect on enterotoxin B production. As the concentration of NaCl increased from 0 to 10%, yields of enterotoxin B and C decreased to undetectable amounts. PMID:5574320

  6. Carbonate adsorption onto goethite as a function of pH and ionic strength

    International Nuclear Information System (INIS)

    Rundberg, R.S.; Albinsson, Y.

    1991-01-01

    The adsorption of carbonate onto geothite was studied as a function of both pH and ionic strength (NaClO 4 electrolyte) using 14 C tracer. The pH ranged from 2.5 to 11.6. The ionic strength was controlled by varying the NaClO 4 concentration and ranged from 0.01 to 0.1 molar. The results indicate that carbonate is adsorbed on goethite as primarily an inner-sphere complex at pH values above the point of zero charge. This is inferred from the lack of dependence on ionic strength in the adsorption of carbonate. Below the point of zero charge carbonate is adsorbed by an additional outer-sphere mechanism. An adsorption isotherm was measured at pH 7.0 with an electrolyte concentration of 0.01M. Deconvolution of the isotherm proved that at least two sorption mechanisms exist. These mechanisms lead to large distribution coefficients at low pH. Thereby making the complete removal and exclusion of carbonate from an aqueous goethite system difficult, for the purpose of characterizing a ''clean'' goethite surface

  7. Carbon dots with strong excitation-dependent fluorescence changes towards pH. Application as nanosensors for a broad range of pH

    Energy Technology Data Exchange (ETDEWEB)

    Barati, Ali [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of); Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Abdollahi, Hamid, E-mail: abd@iasbs.ac.ir [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of)

    2016-08-10

    In this study, preparation of novel pH-sensitive N-doped carbon dots (NCDs) using glucose and urea is reported. The prepared NCDs present strong excitation-dependent fluorescence changes towards the pH that is a new behavior from these nanomaterials. By taking advantage of this unique behavior, two separated ratiometric pH sensors using emission spectra of the NCDs for both acidic (pH 2.0 to 8.0) and basic (pH 7.0 to 14.0) ranges of pH are constructed. Additionally, by considering the entire Excitation–Emission Matrix (EEM) of NCDs as analytical signal and using a suitable multivariate calibration method, a broad range of pH from 2.0 to 14.0 was well calibrated. The multivariate calibration method was independent from the concentration of NCDs and resulted in a very low average prediction error of 0.067 pH units. No changes in the predicted pH under UV irradiation (for 3 h) and at high ionic strength (up to 2 M NaCl) indicated the high stability of this pH nanosensor. The practicality of this pH nanosensor for pH determination in real water samples was validated with good accuracy and repeatability. - Highlights: • Novel pH-sensitive carbon dots with strong FL changes towards pH are reported. • Ratiometric FL pH-sensors for both acidic and basic ranges of pH are constructed. • Multivariate calibration methods were used to calibrate a broad range of pH. • Using EEM of carbon dots and ANN, pH from 2.0 to 14.0 was well calibrated. • The pH prediction is stable even at high ionic strength up to 2 M NaCl.

  8. Carbon dots with strong excitation-dependent fluorescence changes towards pH. Application as nanosensors for a broad range of pH

    International Nuclear Information System (INIS)

    Barati, Ali; Shamsipur, Mojtaba; Abdollahi, Hamid

    2016-01-01

    In this study, preparation of novel pH-sensitive N-doped carbon dots (NCDs) using glucose and urea is reported. The prepared NCDs present strong excitation-dependent fluorescence changes towards the pH that is a new behavior from these nanomaterials. By taking advantage of this unique behavior, two separated ratiometric pH sensors using emission spectra of the NCDs for both acidic (pH 2.0 to 8.0) and basic (pH 7.0 to 14.0) ranges of pH are constructed. Additionally, by considering the entire Excitation–Emission Matrix (EEM) of NCDs as analytical signal and using a suitable multivariate calibration method, a broad range of pH from 2.0 to 14.0 was well calibrated. The multivariate calibration method was independent from the concentration of NCDs and resulted in a very low average prediction error of 0.067 pH units. No changes in the predicted pH under UV irradiation (for 3 h) and at high ionic strength (up to 2 M NaCl) indicated the high stability of this pH nanosensor. The practicality of this pH nanosensor for pH determination in real water samples was validated with good accuracy and repeatability. - Highlights: • Novel pH-sensitive carbon dots with strong FL changes towards pH are reported. • Ratiometric FL pH-sensors for both acidic and basic ranges of pH are constructed. • Multivariate calibration methods were used to calibrate a broad range of pH. • Using EEM of carbon dots and ANN, pH from 2.0 to 14.0 was well calibrated. • The pH prediction is stable even at high ionic strength up to 2 M NaCl.

  9. Salivary pH after a glucose rinse: effect of a new mucoadhesive spray (Cariex) based on sodium bicarbonate and xylitol.

    Science.gov (United States)

    Abbate, G M; Levrini, L; Caria, M P

    2014-01-01

    This study evaluated whether sodium bicarbonate applied on the oral mucosa through a new mucoadhesive spray (Cariex) could control a drop in salivary pH after a glucose rinse, and therefore enhance the buffering potential of saliva. A sample of 50 healthy adults was selected. At day 1, the measurement of salivary pH was performed in the lower fornix in correspondence with the lower molars. Each subject rinsed with 10 ml of a 10% glucose solution and then pH was monitored continually for 40 minutes. At day 2, the same experimental procedure was repeated and three shots of the spray were administered on the oral mucosa. The tested spray is composed of sodium bicarbonate, xylitol, and excipients. Without the mucoadhesive spray, salivary pH became significantly lower following the glucose rinse (p pH remained lower than 6.0 was reduced statistically significantly (p salivary pH was observed for the 40 minutes in which the pH recording was performed. Conclusions: The use of a sodium bicarbonate spray on the mucosa was shown to control the lowering of salivary pH following carbohydrate consumption, and might therefore add to the prevention of caries and dental erosion.

  10. Investigation of sodium - carbon dioxide interactions with calorimetric studies

    International Nuclear Information System (INIS)

    Simon, N.; Latge, C.; Gicquel, L.

    2007-01-01

    The supercritical CO 2 Brayton cycle could be a promising option to enhance the competitiveness of future Sodium fast reactors but it is highly necessary to get thermodynamic and kinetics information on potential sodium-CO 2 chemical reactions and their consequences. We have studied the interaction between Na and CO 2 via calorimetric methods. These methods are able to point out exothermic/endothermic phenomena and to measure heat of chemical reactions. The main feature of the Na/CO 2 interaction seems to be its sharp dependence on temperature. At low temperature, below 500 C degrees, CO 2 and sodium react and exhibit an induction time which decreases when temperature increases. Above 500 C degrees, we observe a global phenomenon with a fast and instantaneous chemical reaction which may be understood as an auto-combustion of CO 2 in sodium. We clearly demonstrated that Na/CO 2 interaction does not proceed as an auto-catalytic process and is more satisfactorily explained by the occurring of an auto-combustion phenomenon

  11. Chemical acceleration of a neutral granulated blast-furnace slag activated by sodium carbonate

    International Nuclear Information System (INIS)

    Kovtun, Maxim; Kearsley, Elsabe P.; Shekhovtsova, Julia

    2015-01-01

    This paper presents results of a study on chemical acceleration of a neutral granulated blast-furnace slag activated using sodium carbonate. As strength development of alkali-activated slag cements containing neutral GBFS and sodium carbonate as activator at room temperature is known to be slow, three accelerators were investigated: sodium hydroxide, ordinary Portland cement and a combination of silica fume and slaked lime. In all cements, the main hydration product is C–(A)–S–H, but its structure varies between tobermorite and riversideite depending on the accelerator used. Calcite and gaylussite are present in all systems and they were formed due to either cation exchange reaction between the slag and the activator, or carbonation. With accelerators, compressive strength up to 15 MPa can be achieved within 24 h in comparison to 2.5 MPa after 48 h for a mix without an accelerator

  12. Carbon coated anatase TiO2 mesocrystals enabling ultrastable and robust sodium storage

    Science.gov (United States)

    Zhang, Weifeng; Lan, Tongbin; Ding, Tianli; Wu, Nae-Lih; Wei, Mingdeng

    2017-08-01

    Nanoporous anatase TiO2 mesocrystals with tunable architectures and crystalline phases were successfully fabricated in the presence of the butyl oleate and oleylamine. Especially, the introduced surfactants served as a carbon source, bring a uniform carbon layer (about 2-8 nm) for heightening the electronic conductivity. The carbon coated TiO2 mesocrystals assembled from crystalline tiny subunits have more space sites for sodium-ion storage. When the material was applied as an electrode material in rechargeable sodium-ion batteries, it exhibited a superior capacity of about 90 mA h g-1 at 20 C (1 C = 168 mA g-1) and a highly reversible capacity for 5000 cycles, which is the longest cycle life reported for sodium storage in TiO2 electrodes.

  13. Biological activity and safety of Tripterygium extract prepared by sodium carbonate extraction.

    Science.gov (United States)

    Fang, Wei; Peng, Fan; Yi, Tao; Zhang, Cong; Wan, Chunxi; Xu, Huibi; Lam, Christopher Waikei; Yang, Xiangliang

    2012-09-17

    The commercial preparation named “Tripterygium glycosides” prepared by column chromatography has been used for the treatment of inflammatory and autoimmune diseases with significant efficacy but concurrent toxicity. The aim of this study was to reduce the toxicity of Tripterygium extracts, using cytotoxicity and anti-inflammatory activity of the three principal active components of Tripterygium wilfordii Hook. F. (TWHF)as guiding parameters. Column chromatography was replaced by sodium carbonate extraction for removing the acidic compounds and enriching epoxyditerpenoids and alkaloids in the extract. Results showed that the therapeutic index (IC50/EC50) on murine macrophage Raw 264.7 cells and rat mesangial HBZY-1 cells of the extract prepared by sodium carbonate extraction was significantly higher than that of Tripterygium glycosides(0.8 and 5.2 vs. 0.3 and 2.6, p sodium carbonate extraction may represent a potentially optimal source of medicine with good therapeutic index.

  14. Paper-based potentiometric pH sensor using carbon electrode drawn by pencil

    Science.gov (United States)

    Kawahara, Ryotaro; Sahatiya, Parikshit; Badhulika, Sushmee; Uno, Shigeyasu

    2018-04-01

    A flexible and disposable paper-based pH sensor fabricated with a pencil-drawn working electrode and a Ag/AgCl paste reference electrode is demonstrated for the first time to show pH response by the potentiometric principle. The sensor substrate is made of chromatography paper with a wax-printed hydrophobic area, and various types of carbon pencils are tested as working electrodes. The pH sensitivities of the electrodes drawn by carbon pencils with different hardnesses range from 16.5 to 26.9 mV/pH. The proposed sensor is expected to be more robust against shape change in electrodes on a flexible substrate than other types of chemiresistive/amperometric pH sensors.

  15. Effect of pH and phosphate on calcium carbonate polymorphs precipitated at near-freezing temperature

    NARCIS (Netherlands)

    Hu, Yu-Bin; Wolthers, Mariëtte; Wolf-Gladrow, Dieter A.; Nehrke, Gernot

    2015-01-01

    The effects of pH and phosphate on the precipitation of calcium carbonate polymorphs from aqueous solution were investigated. Experiments were carried out at near-freezing temperature and two different pH conditions (pH 13.4 and 9.0). At each pH condition, solutions having different concentrations

  16. Studies on sorption of plutonium on inorganic exchangers from sodium carbonate medium

    Energy Technology Data Exchange (ETDEWEB)

    Pius, I C; Charyulu, M M; Sivaramakrishnan, C K [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India); Venkataramani, B [Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Sorption of Pu(IV) from sodium carbonate medium has been investigated by using different inorganic exchangers alumina, silica gel and hydrous titanium oxide. Distribution ratios of Pu(IV) for its sorption on these exchangers from sodium carbonate medium were found to be sufficiently high indicating the suitability of these exchangers for the removal of Pu(IV). The presence of uranium and dibutyl phosphate do not have any effect on distribution ratio. The 10% Pu(IV) breakthrough capacities for above exchangers have been determined with 5 ml bed at a flow rate of 30 ml/hour. (author). 4 refs., 2 tabs.

  17. The evaluation of the efficacy of sodium carbonate as zearalenone destructor in feeding stuffs.

    Science.gov (United States)

    Polak, M; Gajecki, M; Kulik, T; Łuczyński, M K; Obremski, K; Góra, M; Gajecka, M; Jakimiuk, E; Zielonka, Ł

    2009-01-01

    Contamination of feed with zearalenone (ZEA) is still a serious problem in farm animals feeding, especially in gilts, sensitive to this compound. The relative failure of current methods of decontamination and quality control lead us to look for new techniques. The commonly accepted method for breaking down ZEA was performed in controlled temperature and time conditions. Various sodium carbonate doses (0.5 - 4%) were added to feed naturally contaminated with ZEA (ZEA biosynthesis by F. graminearum isolates). These doses were found to be effective in in vitro studies. The addition of 2% sodium carbonate gave the best results in reducing the phytoestrogen in the feed.

  18. Spatial variability of soil carbon, pH, available phosphorous and potassium in organic farm located in Mediterranean Croatia

    Science.gov (United States)

    Bogunović, Igor; Pereira, Paulo; Šeput, Miranda

    2016-04-01

    Soil organic carbon (SOC), pH, available phosphorus (P), and potassium (K) are some of the most important factors to soil fertility. These soil parameters are highly variable in space and time, with implications to crop production. The aim of this work is study the spatial variability of SOC, pH, P and K in an organic farm located in river Rasa valley (Croatia). A regular grid (100 x 100 m) was designed and 182 samples were collected on Silty Clay Loam soil. P, K and SOC showed moderate heterogeneity with coefficient of variation (CV) of 21.6%, 32.8% and 51.9%, respectively. Soil pH record low spatial variability with CV of 1.5%. Soil pH, P and SOC did not follow normal distribution. Only after a Box-Cox transformation, data respected the normality requirements. Directional exponential models were the best fitted and used to describe spatial autocorrelation. Soil pH, P and SOC showed strong spatial dependence with nugget to sill ratio with 13.78%, 0.00% and 20.29%, respectively. Only K recorded moderate spatial dependence. Semivariogram ranges indicate that future sampling interval could be 150 - 200 m in order to reduce sampling costs. Fourteen different interpolation models for mapping soil properties were tested. The method with lowest Root Mean Square Error was the most appropriated to map the variable. The results showed that radial basis function models (Spline with Tension and Completely Regularized Spline) for P and K were the best predictors, while Thin Plate Spline and inverse distance weighting models were the least accurate. The best interpolator for pH and SOC was the local polynomial with the power of 1, while the least accurate were Thin Plate Spline. According to soil nutrient maps investigated area record very rich supply with K while P supply was insufficient on largest part of area. Soil pH maps showed mostly neutral reaction while individual parts of alkaline soil indicate the possibility of penetration of seawater and salt accumulation in the

  19. Effect of pH on turbidity, size, viscosity and the shape of sodium caseinate aggregates with light scattering and rheometry.

    Science.gov (United States)

    Ghorbani Gorji, Sara; Ghorbani Gorji, Elham; Mohammadifar, Mohammad Amin

    2015-03-01

    The characterization of sodium caseinate solutions as a function of pH was determined using titration with HCL through turbidimetry in different concentrations (0.03 wt.%, 0.045 wt.%, 0.06 wt.%, 0.09 wt.%, 0.2 wt.%, and 0.3 wt.%). Additionally, the coupling of slow in situ acidification of the solution and rheometry was utilized to gain deeper insights into pH-induced structural transitions during the self assembly process and particle size distribution analysis have been used to determine the behavior of sodium caseinate solutions in different pHs. The formation of aggregates during the acidification process was clearly visualized using microscopy. Surprisingly the viscosity of sodium caseinate solution at pH 4.64 was maximum and decreased by lowering pH. Particle size analysis confirmed the onset of big aggregates on decreasing pH but further acidification led to formation of smaller aggregates. A small concentration effect on pI was seen where at sodium caseinate levels of 0.03 wt.% the pI occurred at 4.29, where at sodium caseinate levels of 0.30 wt.% pI value was 4.64.

  20. Analysis of carbon transport in the EBR-II and FFTF primary sodium systems

    International Nuclear Information System (INIS)

    Snyder, R.B.; Natesan, K.; Kassner, T.F.

    1976-01-01

    An analysis of the carburization-decarburization behavior of austenitic stainless steels in the primary heat-transport systems of the EBR-II and FFTF has been made that is based upon a kinetic model for the diffusion process and the surface area of steel in contact with flowing sodium at various temperatures in the two systems. The analysis was performed for operating conditions that result in sodium outlet temperatures of 474 and 566 0 C in the FFTF and 470 0 C in the EBR-II. If there was no external source of carbon to the system, i.e., other than the carbon initially present in the steel and the sodium, the dynamic-equilibrium carbon concentrations calculated for the FFTF primary sodium were approximately 0.025 and approximately 0.065 ppm for the 474 and 566 0 C outlet temperatures, respectively, and approximately 0.018 ppm for the EBR-II primary system. The analysis indicated that a carbon-source rate of approximately 250 g/y would be required to increase the carbon concentration of the EBR-II sodium to the measured range of approximately 0.16--0.19 ppm. An evaluation of possible carbon sources and the amount of carbonaceous material introduced into the reactor cover gas and sodium suggests that the magnitude of the calculated contamination rate is reasonable. For a 566 0 C outlet temperature, carbonaceous material would have to be introduced into the FFTF primary system at a rate approximately 4--6 times higher than in EBR-II to achieve the same carbon concentration in the sodium in the two systems. Since contamination rates of approximately 1500 g/y are unlikely, high-temperature fuel cladding in the FFTF should exhibit decarburization similar to that observed in laboratory loop systems, in contrast to the minimal compositional changes that result after exposure of Type 316 stainless steel to EBR-II sodium at temperatures between approximately 625 and 650 0 C

  1. A tunable ratiometric pH sensor based on carbon nanodots for the quantitative measurement of the intracellular pH of whole cells.

    Science.gov (United States)

    Shi, Wen; Li, Xiaohua; Ma, Huimin

    2012-06-25

    The whole picture: Carbon nanodots labeled with two fluorescent dyes have been developed as a tunable ratiometric pH sensor to measure intracellular pH. The nanosensor shows good biocompatibility and cellular dispersibility. Quantitative determinations on intact HeLa cells and pH fluctuations associated with oxidative stress were performed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Antimony leaching from MSWI bottom ash: modelling of the effect of pH and carbonation.

    Science.gov (United States)

    Cornelis, Geert; Van Gerven, Tom; Vandecasteele, Carlo

    2012-02-01

    Development of treatment methods to reduce Sb leaching from municipal solid waste incinerator (MSWI) bottom ash, such as accelerated carbonation, is being complicated by insufficient understanding of Sb geochemistry. The leaching of antimonate (Sb(V)) and antimonite (Sb(III)) in MSWI bottom was studied as a function of pH and degree of carbonation. While total (Sb(V)+Sb(III)) leaching was lowest (1.2 mg kg(-1)) at the natural pH (i.e. 10.6) of uncarbonated bottom ash, HPLC-ICP-MS analysis showed that acidification and carbonation increased Sb(V) leaching, but decreased Sb(III) leaching, probably because Sb(III)(OH)(4)(-) became less stable. PHREEQC geochemical modelling suggested that Sb(V) concentrations approached equilibrium with the romeites, i.e. calcium antimonates, Ca(1.13)Sb(2)(OH)(0.26)·0.74H(2)O at pH=10.6 and Ca[Sb(OH)(6)](2) at pH=8. It is hypothesised that not interaction with ettringite but dissolution of romeite controls antimonate leaching in the pH range 8-11 in MSWI bottom ash, because while Ca is preferentially leached from romeite, the mineral structures containing more Ca at higher pH are less soluble. A model was proposed where acidification and carbonation both lead to lower Ca(2+) and/or hydroxyl concentration, which removes Ca(2+) and hydroxyls from the romeite structure and leads to comparably higher Sb(V) concentration in equilibrium with romeite. Sb solubility depends on pH and Ca(2+) availability in this model, which has implications for bottom ash valorisation and risk assessment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Effect of carbon activity on the creep behaviour of 21/4Cr, 1Mo steel in sodium

    International Nuclear Information System (INIS)

    Cordwell, J.E.; Charnock, W.; Nicholson, R.D.

    1979-02-01

    The creep endurance and creep cracking behaviour of 2 1/4Cr, 1Mo steel in sodium at 475 0 C have been studied at three different sodium carbon activities. Creep endurance was found to increase with increasing carbon activity of the sodium. Tests carried out in high carbon activity sodium were discontinued before fracture. Creep crack initiation displacement at notches decreased with increasing carbon activity, presumably as a result of notch tip carburisation. The plastic zones at the tips of blunt notches in specimens exposed in high carbon activity sodium were preferentially carburised. These observations were similar to those made previously on 9Cr, 1Mo steel. One difference detected metallographically was that in a high carburising environment uniform carburisation was obtained in the 2 1/4Cr, 1Mo steel specimens whereas carburisation gradients were observed in the 9Cr, 1Mo steel. Creep crack propagation rates for given notch opening displacement rates in low and intermediate carbon activity sodium were indistinguishable. However, the strenthening that resulted from the mild carburisation of the specimen in the intermediate carbon activity sodium caused slower notch opening displacement rates and crack propagation rates than in the low carbon activity sodium, when the rates were compared at the same crack length. (author)

  4. The variation of calcium, magnesium, sodium, potassium and bicarbonate concentration, pH and conductivity in groundwater of Karachi region

    International Nuclear Information System (INIS)

    Zubair, A.; Ali, S.I.

    2002-01-01

    Groundwater in Karachi is influenced mainly by the evaporation / crystallization process as expressed by the Na/(Na+Ca) weight concentration ratio. The high coefficient of determined between conductivity and total dissolved ions concentration in meq/sup -1/ revealed that major ions affect the conductivity of groundwater. It was also found that groundwater quality with respect to cations is not significantly influenced by geology, particularly in the Urban are of the city, where the 90% of the population resides. The relationship between conductivity and bicarbonate concentration shows that supersaturation of groundwater with carbon dioxide is responsible for general depression of pH. (author)

  5. Rubber-based carbon electrode materials derived from dumped tires for efficient sodium-ion storage.

    Science.gov (United States)

    Wu, Zhen-Yue; Ma, Chao; Bai, Yu-Lin; Liu, Yu-Si; Wang, Shi-Feng; Wei, Xiao; Wang, Kai-Xue; Chen, Jie-Sheng

    2018-04-03

    The development of sustainable and low cost electrode materials for sodium-ion batteries has attracted considerable attention. In this work, a carbon composite material decorated with in situ generated ZnS nanoparticles has been prepared via a simple pyrolysis of the rubber powder from dumped tires. Upon being used as an anode material for sodium-ion batteries, the carbon composite shows a high reversible capacity and rate capability. A capacity as high as 267 mA h g-1 is still retained after 100 cycles at a current density of 50 mA g-1. The well dispersed ZnS nanoparticles in carbon significantly enhance the electrochemical performance. The carbon composites derived from the rubber powder are proposed as promising electrode materials for low-cost, large-scale energy storage devices. This work provides a new and effective method for the reuse of dumped tires, contributing to the recycling of valuable waste resources.

  6. Room temperature synthesis of glycerol carbonate catalyzed by spray dried sodium aluminate microspheres

    OpenAIRE

    Sreerangappa, Ramesh; Debecker, Damien P.; 13th European Congress on Catalysis – EuropaCat 2017

    2017-01-01

    Nanostructured NaAlO2 microspheres are produced by one-pot spray dried route, and are characterized by various physico-chemical methods. The obtained solids are composed of spherical aggregates of sodium aluminate with small crystallite size and strong surface basicity. This makes them highly active catalysts in the base-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The catalyst does not leach and showed good reusability up to three cycles.

  7. Role of Sodium Bicarbonate Cotransporters in Intracellular pH Regulation and Their Regulatory Mechanisms in Human Submandibular Glands.

    Science.gov (United States)

    Namkoong, Eun; Shin, Yong-Hwan; Bae, Jun-Seok; Choi, Seulki; Kim, Minkyoung; Kim, Nahyun; Hwang, Sung-Min; Park, Kyungpyo

    2015-01-01

    Sodium bicarbonate cotransporters (NBCs) are involved in the pH regulation of salivary glands. However, the roles and regulatory mechanisms among different NBC isotypes have not been rigorously evaluated. We investigated the roles of two different types of NBCs, electroneutral (NBCn1) and electrogenic NBC (NBCe1), with respect to pH regulation and regulatory mechanisms using human submandibular glands (hSMGs) and HSG cells. Intracellular pH (pHi) was measured and the pHi recovery rate from cell acidification induced by an NH4Cl pulse was recorded. Subcellular localization and protein phosphorylation were determined using immunohistochemistry and co-immunoprecipitation techniques. We determined that NBCn1 is expressed on the basolateral side of acinar cells and the apical side of duct cells, while NBCe1 is exclusively expressed on the apical membrane of duct cells. The pHi recovery rate in hSMG acinar cells, which only express NBCn1, was not affected by pre-incubation with 5 μM PP2, an Src tyrosine kinase inhibitor. However, in HSG cells, which express both NBCe1 and NBCn1, the pHi recovery rate was inhibited by PP2. The apparent difference in regulatory mechanisms for NBCn1 and NBCe1 was evaluated by artificial overexpression of NBCn1 or NBCe1 in HSG cells, which revealed that the pHi recovery rate was only inhibited by PP2 in cells overexpressing NBCe1. Furthermore, only NBCe1 was significantly phosphorylated and translocated by NH4Cl, which was inhibited by PP2. Our results suggest that both NBCn1 and NBCe1 play a role in pHi regulation in hSMG acinar cells, and also that Src kinase does not regulate the activity of NBCn1.

  8. Role of Sodium Bicarbonate Cotransporters in Intracellular pH Regulation and Their Regulatory Mechanisms in Human Submandibular Glands.

    Directory of Open Access Journals (Sweden)

    Eun Namkoong

    Full Text Available Sodium bicarbonate cotransporters (NBCs are involved in the pH regulation of salivary glands. However, the roles and regulatory mechanisms among different NBC isotypes have not been rigorously evaluated. We investigated the roles of two different types of NBCs, electroneutral (NBCn1 and electrogenic NBC (NBCe1, with respect to pH regulation and regulatory mechanisms using human submandibular glands (hSMGs and HSG cells. Intracellular pH (pHi was measured and the pHi recovery rate from cell acidification induced by an NH4Cl pulse was recorded. Subcellular localization and protein phosphorylation were determined using immunohistochemistry and co-immunoprecipitation techniques. We determined that NBCn1 is expressed on the basolateral side of acinar cells and the apical side of duct cells, while NBCe1 is exclusively expressed on the apical membrane of duct cells. The pHi recovery rate in hSMG acinar cells, which only express NBCn1, was not affected by pre-incubation with 5 μM PP2, an Src tyrosine kinase inhibitor. However, in HSG cells, which express both NBCe1 and NBCn1, the pHi recovery rate was inhibited by PP2. The apparent difference in regulatory mechanisms for NBCn1 and NBCe1 was evaluated by artificial overexpression of NBCn1 or NBCe1 in HSG cells, which revealed that the pHi recovery rate was only inhibited by PP2 in cells overexpressing NBCe1. Furthermore, only NBCe1 was significantly phosphorylated and translocated by NH4Cl, which was inhibited by PP2. Our results suggest that both NBCn1 and NBCe1 play a role in pHi regulation in hSMG acinar cells, and also that Src kinase does not regulate the activity of NBCn1.

  9. Structural and surface functionality changes in reticulated vitreous carbon produced from poly(furfuryl alcohol) with sodium hydroxide additions

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, Silvia Sizuka, E-mail: silviaoishi@uol.com.br [LAS, Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas 1758, São José dos Campos, SP 12227-010 (Brazil); Botelho, Edson Cocchieri [Departamento de Materiais e Tecnologia, Univ Estadual Paulista (UNESP), Av. Doutor Ariberto Pereira da Cunha 333, Guaratinguetá, SP 12516-410 (Brazil); Rezende, Mirabel Cerqueira [Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP), Rua Talim 330, São José dos Campos, SP 12231-280 (Brazil); Ferreira, Neidenêi Gomes [LAS, Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas 1758, São José dos Campos, SP 12227-010 (Brazil)

    2017-02-01

    Highlights: • Reticulated vitreous carbon (RVC) was processed from poly(furfuryl alcohol) with different amounts of NaOH. • A correlation between microstructure and surface functionalities was proposed. • The structural ordering was mainly influenced by the cured PFA polymerization degree and carboxylic acid content on RVC surface. - Abstract: The use of sodium hydroxide to neutralize the acid catalyst increases the storage life of poly(furfuryl alcohol) (PFA) resin avoiding its continuous polymerization. In this work, a concentrated sodium hydroxide solution (NaOH) was added directly to the PFA resin in order to minimize the production of wastes generated when PFA is washed with diluted basic solution. Thus, different amounts of this concentrated basic solution were added to the resin up to reaching pH values of around 3, 5, 7, and 9. From these four types of modified PFA two sample sets of reticulated vitreous carbon (RVC) were processed and heat treated at two different temperatures (1000 and 1700 °C). A correlation among cross-link density of PFA and RVC morphology, structural ordering and surface functionalities was systematically studied using Fourier transform infrared spectroscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The PFA neutralization (pH 7) led to its higher polymerization degree, promoting a crystallinity decrease on RVC treated at 1000 °C as well as its highest percentages of carboxylic groups on surface. A NaOH excess (pH 9) substantially increased the RVC oxygen content, but its crystallinity remained similar to those for samples from pH 3 and 5 treated at 1000 °C, probably due to the reduced presence of carboxylic group and the lower polymerization degree of its cured resin. Samples with pH 3 and 5 heat treated at 1000 and 1700 °C can be considered the most ordered which indicated that small quantities of NaOH may be advantageous to minimize continuous

  10. sodium

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les initiatives de réduction de la consommation de sel qui visent l'ensemble de la population et qui ciblent la teneur en sodium des aliments et sensibilisent les consommateurs sont susceptibles de réduire la consommation de sel dans toutes les couches de la population et d'améliorer la santé cardiovasculaire. Ce projet a ...

  11. Microelectrode characterization of coral daytime interior pH and carbonate chemistry.

    Science.gov (United States)

    Cai, Wei-Jun; Ma, Yuening; Hopkinson, Brian M; Grottoli, Andréa G; Warner, Mark E; Ding, Qian; Hu, Xinping; Yuan, Xiangchen; Schoepf, Verena; Xu, Hui; Han, Chenhua; Melman, Todd F; Hoadley, Kenneth D; Pettay, D Tye; Matsui, Yohei; Baumann, Justin H; Levas, Stephen; Ying, Ye; Wang, Yongchen

    2016-04-04

    Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of coral calcification mechanisms. However, the concentration and speciation of dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter to constrain carbonate chemistry has been missing. Here we report the first carbonate ion concentration ([CO3(2-)]) measurements together with pH inside corals during the light period. We observe sharp increases in [CO3(2-)] and pH from the gastric cavity to the calcifying fluid, confirming the existence of a proton (H(+)) pumping mechanism. We also show that corals can achieve a high aragonite saturation state (Ωarag) in the calcifying fluid by elevating pH while at the same time keeping [DIC] low. Such a mechanism may require less H(+)-pumping and energy for upregulating pH compared with the high [DIC] scenario and thus may allow corals to be more resistant to climate change related stressors.

  12. Activated carbon addition affects substrate pH and germination of six plant species

    NARCIS (Netherlands)

    Kabouw, P.; Nab, M.; Dam, van M.

    2010-01-01

    Activated carbon (AC) is widely used in ecological studies for neutralizing allelopathic compounds. However, it has been suggested that AC has direct effects on plants because it alters substrate parameters such as nutrient availability and pH. These side-effects of AC addition may interfere with

  13. Activated carbon addition affects soil pH and germination of six plant species

    NARCIS (Netherlands)

    Kabouw, P.; Nab, M.R.; Van Dam, N.M.

    2010-01-01

    Activated carbon (AC) is widely used in ecological studies for neutralizing allelopathic compounds. However, it has been suggested that AC has direct effects on plants because it alters substrate parameters such as nutrient availability and pH. These side-effects of AC addition may interfere with

  14. Estimating marine biogeochemical rates of the carbonate pH system—A Kalman filter tested

    NARCIS (Netherlands)

    Soetaert, K.E.R.; Grégoire, M.

    2011-01-01

    Oxygen (O2), nitrate (NO3), dissolved inorganic carbon (DIC) or pCO2, and pH or total alkalinity (TA), are useful indices of marine chemical, physical and biological processes operating on varying time-scales. Although these properties are increasingly being monitored at high frequency, they have

  15. Sodium carbonate activated slag as cement replacement in autoclaved aerated concrete

    NARCIS (Netherlands)

    Yuan, B.; Straub, C.; Segers, S.; Yu, Q.; Brouwers, H.J.H.

    2017-01-01

    This paper aims to study the suitability of fully replacing cement by sodium carbonate activated slag in producing autoclaved aerated concrete (AAC). The material properties of the product are characterized in terms of green strength development, mechanical properties, pore related properties such

  16. Autogenous and drying shrinkage of sodium carbonate activated slag altered by limestone powder incorporation

    NARCIS (Netherlands)

    Yuan, B.; Yu, Q.L.; Dainese, E.; Brouwers, H.J.H.

    2017-01-01

    This paper aims to study the shrinkage mechanism of sodium carbonate activated slag containing limestone powder (LP). The workability, pore structure, reaction kinetics and strength development were characterized. The results show that the autogenous shrinkage increases when the dosage of LP is low

  17. Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

    NARCIS (Netherlands)

    Yuan, B.; Yu, Q.; Brouwers, H.J.H.

    2017-01-01

    This study aims to investigate the effect of limestone powder (LP) on the reaction of sodium carbonate activated slag. The results show that the incorporated LP up to 30% improves the strength development, especially at advanced curing ages. A slightly accelerated reaction is observed for samples

  18. The determination of hydroxide and carbonate in concentrated sodium chloride solutions

    NARCIS (Netherlands)

    Roolvink, W.B.; Bos, M.

    1980-01-01

    A computer method for the determination of carbonate and hydroxide in concentrated (2.89 M) sodium chloride solutions is described. The method is based on multiparametric curve-fitting and can also be applied to salts of dibasic acids with unknown equilibrium constants. The systematic error is not

  19. Efficacy of Sodium Carbonate Peroxyhydrate as A Catfish Egg Disinfectant and Comparison to Hydrogen Peroxide

    Science.gov (United States)

    Two experiments were conducted to evaluate the efficacy of sodium carbonate peroxyhydrate (SCP) for improving channel catfish Ictalurus punctatus hatching success when used as a prophylactic chemotherapeutant during egg incubation. In the first experiment, efficacy of SCP was evaluated in 379-L, al...

  20. Influences of sodium carbonate on physicochemical properties of lansoprazole in designed multiple coating pellets.

    Science.gov (United States)

    He, Wei; Yang, Min; Fan, Jun Hong; Feng, Cai Xia; Zhang, Su Juan; Wang, Jin Xu; Guan, Pei Pei; Wu, Wei

    2010-09-01

    Lansoprazole (LSP), a proton-pump inhibitor, belongs to class II drug. It is especially instable to heat, light, and acidic media, indicating that fabrication of a formulation stabilizing the drug is difficult. The addition of alkaline stabilizer is the most powerful method to protect the drug in solid formulations under detrimental environment. The purpose of the study was to characterize the designed multiple coating pellets of LSP containing an alkaline stabilizer (sodium carbonate) and assess the effect of the stabilizer on the physicochemical properties of the drug. The coated pellets were prepared by layer-layer film coating with a fluid-bed coater. In vitro release and acid-resistance studies were carried out in simulated gastric fluid and simulated intestinal fluid, respectively. Furthermore, the moisture-uptake test was performed to evaluate the influence of sodium carbonate on the drug stability. The results indicate that the drug exists in the amorphous state or small (nanometer size) particles without crystallization even after storage at 40°C/75% for 5 months. The addition of sodium carbonate to the pellet protects the drug from degradation in simulated gastric fluid in a dose-dependent manner. The moisture absorbed into the pellets has a detrimental effect on the drug stability. The extent of drug degradation is directly correlated with the content of moisture absorption. In conclusion, these results suggest that the presence of sodium carbonate influence the physicochemical properties of LSP, and the designed multiple coating pellets enhance the drug stability.

  1. Voltammetric Determination of Ivabradine Hydrochloride Using Multiwalled Carbon Nanotubes Modified Electrode in Presence of Sodium Dodecyl Sulfate

    Directory of Open Access Journals (Sweden)

    Ali Kamal Attia

    2017-04-01

    Full Text Available Purpose: A new sensitive sensor was fabricated for the determination of ivabradine hydrochloride (IH based on modification with multiwalled carbon nanotubes using sodium dodecyl sulfate as micellar medium to increase the sensitivity. Methods: The electrochemical behavior of IH was studied in Britton-Robinson buffer (pH: 2.0-11.0 using cyclic and differential pulse voltammetry. Results: The voltammetric response was linear over the range of 3.984 x 10-6-3.475 x 10-5 mol L-1. The limits of detection and quantification were found to be 5.160 x 10-7 and 1.720 x 10-6 mol L-1, respectively. Conclusion: This method is suitable for determination of IH in tablets and plasma.

  2. Voltammetric Determination of Ivabradine Hydrochloride Using Multiwalled Carbon Nanotubes Modified Electrode in Presence of Sodium Dodecyl Sulfate.

    Science.gov (United States)

    Attia, Ali Kamal; Abo-Talib, Nisreen Farouk; Tammam, Marwa Hosny

    2017-04-01

    Purpose: A new sensitive sensor was fabricated for the determination of ivabradine hydrochloride (IH) based on modification with multiwalled carbon nanotubes using sodium dodecyl sulfate as micellar medium to increase the sensitivity. Methods: The electrochemical behavior of IH was studied in Britton-Robinson buffer (pH: 2.0-11.0) using cyclic and differential pulse voltammetry. Results: The voltammetric response was linear over the range of 3.984 x 10 -6 -3.475 x 10 -5 mol L -1 . The limits of detection and quantification were found to be 5.160 x 10 -7 and 1.720 x 10-6 mol L -1 , respectively. Conclusion: This method is suitable for determination of IH in tablets and plasma.

  3. Oxidation Behavior of Carbon Steel: Effect of Formation Temperature and pH of the Environment

    Science.gov (United States)

    Dubey, Vivekanand; Kain, Vivekanand

    2017-11-01

    The nature of surface oxide formed on carbon steel piping used in nuclear power plants affects flow-accelerated corrosion. In this investigation, carbon steel specimens were oxidized in an autoclave using demineralized water at various temperatures (150-300 °C) and at pH levels (neutral, 9.5). At low temperatures ( 240 °C) as confirmed by scanning electron microscopy. Electrochemical impedance measurement followed by Mott-Schottky analysis indicated an increase in defect density with exposure duration at 150 °C at neutral pH but a low and stable defect density in alkaline environment. The defect density of the oxide formed at neutral pH at 150-300 °C was always higher than that formed in alkaline environment as reported in the literature.

  4. Characteristics of Sodium Polyacrylate/Nano-Sized Carbon Hydrogel for Biomedical Patch.

    Science.gov (United States)

    Park, Jong-Kyu; Seo, Sun-Kyo; Cho, Seungkwan; Kim, Han-Sung; Lee, Chi-Hwan

    2018-03-01

    Conductive hydrogels were prepared for biomedical patch in order to improve the electrical conductivity. Sodium polyacrylate and nano-sized carbon were mixed and fabricated by aqueous solution gelation process in various contents of nano-sized carbon with 0.1, 0.5, 1.0 and 2.0 wt%. Sodium polyacrylate/nano-sized carbon conductive hydrogels were investigated by molecular structure, surface morphology and electrical conductivity. The conductivity of the hydrogel/nano-sized carbon conductive hydrogel proved to be 10% higher than conductive hydrogel without nano-sized carbon. However, it was founded that conductive hydrogels with nano-sized carbon content from 0.5 up to 2.0 wt% were remarkably decreased. This may be due to the non-uniform distribution of nano-sized carbon, resulting from agglomerates of nano-sized carbon. The developed hydrogel is intended for use in the medical and cosmetic fields that is applicable to supply micro-current from device to human body.

  5. Effects of sodium bicarbonate on the end-tidal CO2, PaCO2, HCO3-, PH and cerebral blood flow

    International Nuclear Information System (INIS)

    Komatani, Akio; Akutsu, Tooru; Yoshida, Michihiko; Yamaguchi, Koichi; Seo, Hiroshi

    1992-01-01

    To estimate the quantitative reactivity of cerebral blood flow (CBF), the effects of sodium bicarbonate on the end-tidal CO 2 , arterial partial pressure of CO 2 (PaCO 2 ), HCO 3 - , pH and CBF were examined. The CBF was measured by 133 Xe inhalation method with ring type SPECT (HEADTOME). Activation study with sodium bicarbonate administration was performed after 30 minutes of resting study, and the reactivity of each parameters was investigated. The arterial HCO 3 - and pH increased with similar reactivity, but PaCO 2 , end-tidal CO 2 and CBF in the non-injured hemisphere changed with irregular reactivity. The excellent correlation between PaCO 2 and end-tidal CO 2 was vanished by the administration of sodium bicarbonate. The reactivity of CBF did not correlate with reactivity of PaCO 2 and end-tidal CO 2 , but correlated with arterial HCO 3 - and pH. Thus the measurement of arterial HCO 3 - and pH may be indispensable to estimate the CBF reactivity with the administration of sodium bicarbonate. (author)

  6. Effects of sodium bicarbonate on the end-tidal CO[sub 2], PaCO[sub 2], HCO[sub 3][sup -], PH and cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Komatani, Akio; Akutsu, Tooru; Yoshida, Michihiko; Yamaguchi, Koichi; Seo, Hiroshi (Yamagata Univ. (Japan). School of Medicine)

    1992-09-01

    To estimate the quantitative reactivity of cerebral blood flow (CBF), the effects of sodium bicarbonate on the end-tidal CO[sub 2], arterial partial pressure of CO[sub 2] (PaCO[sub 2]), HCO[sub 3][sup -], pH and CBF were examined. The CBF was measured by [sup 133]Xe inhalation method with ring type SPECT (HEADTOME). Activation study with sodium bicarbonate administration was performed after 30 minutes of resting study, and the reactivity of each parameters was investigated. The arterial HCO[sub 3][sup -] and pH increased with similar reactivity, but PaCO[sub 2], end-tidal CO[sub 2] and CBF in the non-injured hemisphere changed with irregular reactivity. The excellent correlation between PaCO[sub 2] and end-tidal CO[sub 2] was vanished by the administration of sodium bicarbonate. The reactivity of CBF did not correlate with reactivity of PaCO[sub 2] and end-tidal CO[sub 2], but correlated with arterial HCO[sub 3][sup -] and pH. Thus the measurement of arterial HCO[sub 3][sup -] and pH may be indispensable to estimate the CBF reactivity with the administration of sodium bicarbonate. (author).

  7. Behavior of sodium chloride during the combustion of carbon

    Energy Technology Data Exchange (ETDEWEB)

    Brinsmead, K H; Kear, R W

    1956-01-01

    The effects of combustion time, temperature, atmosphere, and the presence of other minerals on the release of Na and Cl from carbon that contained varying amounts of NaCl were examined. Initial testing consisted of adding 0.25, 12.7 and 2.54% NaCl to carbon, and pelletizing and burning the carbon for an hour at the following temperatures: 700, 800, 900, and 1000/sup 0/C. Pellets containing 1.27% NaCl were also burned at 400, 500, and 600/sup 0/C. Additional testing involved the combustion of pellets in dry nitrogen, dry air, moist nitrogen, moist air, and adding various amounts of kaolin to the carbon prior to pelletizing. The testing program demonstrated the following: in all tests the percentage of Na and Cl released increased as the temperature and the salt content increased; generally more Cl was released than Na, particularly at temperatures between 600 to 900 degrees; the release of Na and Cl was significantly less in an atmosphere of N, particularly at lower temperatures; the water vapor present in the moist air seemed to hinder the release of Na but increased the amount of Cl released; a reduction in the amount of Na but not the amount of Cl released was noticed when kaolin was added. The following was concluded from the test results: since Na and Cl were released at different rates there seems to be more than a physical volatization involved; water vapor in the air could affect the amount of Na and Clreleased by lowering the combustion temperature of the carbon, thereby allowing the Na and Cl to react with the water present to form NaOH and HC1; and the reduction in the amount of Na released when kaolin was added was a result of Na reacting with kaolin to form an insoluble silicate.

  8. Ubiquinone modified printed carbon electrodes for cell culture pH monitoring.

    Science.gov (United States)

    McBeth, Craig; Dughaishi, Rajaa Al; Paterson, Andrew; Sharp, Duncan

    2018-08-15

    The measurement of pH is important throughout many biological systems, but there are limited available technologies to enable its periodical monitoring in the complex, small volume, media often used in cell culture experiments across a range of disciplines. Herein, pad printed electrodes are developed and characterised through modification with: a commercially available fullerene multiwall carbon nanotube composite applied in Nafion, casting of hydrophobic ubiquinone as a pH probe to provide the electrochemical signal, and coated in Polyethylene glycol to reduce fouling and potentially enhance biocompatibility, which together are proven to enable the determination of pH in cell culture media containing serum. The ubiquinone oxidation peak position (E pa ) provided an indirect marker of pH across the applicable range of pH 6-9 (R 2 = 0.9985, n = 15) in complete DMEM. The electrochemical behaviour of these sensors was also proven to be robust; retaining their ability to measure pH in cell culture media supplemented with serum up to 20% (v/v) [encompassing the range commonly employed in cell culture], cycled > 100 times in 10% serum containing media and maintain > 60% functionality after 5 day incubation in a 10% serum containing medium. Overall, this proof of concept research highlights the potential applicability of this, or similar, electrochemical approaches to enable to detection or monitoring of pH in complex cell culture media. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Solvation behavior of carbonate-based electrolytes in sodium ion batteries.

    Science.gov (United States)

    Cresce, Arthur V; Russell, Selena M; Borodin, Oleg; Allen, Joshua A; Schroeder, Marshall A; Dai, Michael; Peng, Jing; Gobet, Mallory P; Greenbaum, Steven G; Rogers, Reginald E; Xu, Kang

    2016-12-21

    Sodium ion batteries are on the cusp of being a commercially available technology. Compared to lithium ion batteries, sodium ion batteries can potentially offer an attractive dollar-per-kilowatt-hour value, though at the penalty of reduced energy density. As a materials system, sodium ion batteries present a unique opportunity to apply lessons learned in the study of electrolytes for lithium ion batteries; specifically, the behavior of the sodium ion in an organic carbonate solution and the relationship of ion solvation with electrode surface passivation. In this work the Li + and Na + -based solvates were characterized using electrospray mass spectrometry, infrared and Raman spectroscopy, 17 O, 23 Na and pulse field gradient double-stimulated-echo pulse sequence nuclear magnetic resonance (NMR), and conductivity measurements. Spectroscopic evidence demonstrate that the Li + and Na + cations share a number of similar ion-solvent interaction trends, such as a preference in the gas and liquid phase for a solvation shell rich in cyclic carbonates over linear carbonates and fluorinated carbonates. However, quite different IR spectra due to the PF 6 - anion interactions with the Na + and Li + cations were observed and were rationalized with the help of density functional theory (DFT) calculations that were also used to examine the relative free energies of solvates using cluster - continuum models. Ion-solvent distances for Na + were longer than Li + , and Na + had a greater tendency towards forming contact pairs compared to Li + in linear carbonate solvents. In tests of hard carbon Na-ion batteries, performance was not well correlated to Na + solvent preference, leading to the possibility that Na + solvent preference may play a reduced role in the passivation of anode surfaces and overall Na-ion battery performance.

  10. Molecular dynamics simulations of a lithium/sodium carbonate mixture.

    Science.gov (United States)

    Ottochian, Alistar; Ricca, Chiara; Labat, Frederic; Adamo, Carlo

    2016-03-01

    The diffusion and ionic conductivity of Li x Na1-x CO3 salt mixtures were studied by means of Molecular Dynamics (MD) simulations, using the Janssen and Tissen model (Janssen and Tissen, Mol Simul 5:83-98; 1990). These salts have received particular attention due to their central role in fuel cells technology, and reliable numerical methods that could perform as important interpretative tool of experimental data are thus required but still lacking. The chosen computational model nicely reproduces the main structural behaviour of the pure Li2CO3, Na2CO3 and K2CO3 carbonates, but also of their Li/K and Li/Na mixtures. However, it fails to accurately describe dynamic properties such as activation energies of diffusion and conduction processes, outlining the need to develop more accurate models for the simulation of molten salt carbonates.

  11. Development and characterization of a voltammetric carbon-fiber microelectrode pH sensor.

    Science.gov (United States)

    Makos, Monique A; Omiatek, Donna M; Ewing, Andrew G; Heien, Michael L

    2010-06-15

    This work describes the development and characterization of a modified carbon-fiber microelectrode sensor capable of measuring real-time physiological pH changes in biological microenvironments. The reagentless sensor was fabricated under ambient conditions from voltammetric reduction of the diazonium salt Fast Blue RR onto a carbon-fiber surface in aprotic media. Fast-scan cyclic voltammetry was used to probe redox activity of the p-quinone moiety of the surface-bound molecule as a function of pH. In vitro calibration of the sensor in solutions ranging from pH 6.5 to 8.0 resulted in a pH-dependent anodic peak potential response. Flow-injection analysis was used to characterize the modified microelectrode, revealing sensitivity to acidic and basic changes discernible to 0.005 pH units. Furthermore, the modified electrode was used to measure dynamic in vivo pH changes evoked during neurotransmitter release in the central nervous system of the microanalytical model organism Drosophila melanogaster.

  12. Carbonic acid ionization and the stability of sodium bicarbonate and carbonate ion pairs to 200 °C - A potentiometric and spectrophotometric study

    Science.gov (United States)

    Stefánsson, Andri; Bénézeth, Pascale; Schott, Jacques

    2013-11-01

    Carbonic acid ionization and sodium bicarbonate and carbonate ion pair formation constants have been experimentally determined in dilute hydrothermal solutions to 200 °C. Two experimental approaches were applied, potentiometric acid-base titrations at 10-60 °C and spectrophotometric pH measurements using the pH indicators, 2-napthol and 4-nitrophenol, at 25-200 °C. At a given temperature, the first and second ionization constants of carbonic acid (K1, K2) and the ion pair formation constants for NaHCO(aq)(K) and NaCO3-(aq)(K) were simultaneously fitted to the data. Results of this study compare well with previously determined values of K1 and K2. The NaHCO(aq) and NaCO3-(aq) ion pair formation constants vary between 25 and 200 °C having values of logK=-0.18 to 0.58 and logK=1.01 to 2.21, respectively. These ion pairs are weak at low-temperatures but become increasingly important with increasing temperature under neutral to alkaline conditions in moderately dilute to concentrated NaCl solutions, with NaCO3-(aq) predominating over CO32-(aq) in ⩾0.1 M NaCl solution at temperatures above 100 °C. The results demonstrate that NaCl cannot be considered as an inert (non-complexing) electrolyte in aqueous carbon dioxide containing solutions at elevated temperatures.

  13. The monitoring of oxygen, hydrogen and carbon in the sodium circuits of the PFR

    International Nuclear Information System (INIS)

    Mason, L.; Morrison, N.S.; Robertson, C.M.; Trevillion, E.A.

    1984-01-01

    The paper reviews the instrumentation available for monitoring oxygen, hydrogen, tritium and carbon impurity levels on the primary and secondary circuits of PFR. Circuit oxygen levels measured using electrochemical oxygen meters are compared to estimates from circuit plugging meters. The data are interpreted in the light of information from cold trap temperatures. Measurements of secondary circuit hydrogen levels using both the sodium and gas phase hydrogen detection equipment are compared to estimates of circuit hydrogen levels from plugging meters and variations in sodium phase hydrogen levels during power operation are discussed. (author)

  14. Increased blood pH but not performance with sodium bicarbonate supplementation in elite rugby union players.

    Science.gov (United States)

    Cameron, Sonya L; McLay-Cooke, Rebecca T; Brown, Rachel C; Gray, Andrew R; Fairbairn, Kirsty A

    2010-08-01

    This study investigated the effect of ingesting 0.3 g/kg body weight (BW) of sodium bicarbonate (NaHCO₃) on physiological responses, gastrointestinal (GI) tolerability, and sprint performance in elite rugby union players. Twenty-five male rugby players, age 21.6 (2.6) yr, participated in a randomized, double-blind, placebo-controlled crossover trial. Sixty-five minutes after consuming 0.3 g/kg BW of either NaHCO₃ or placebo, participants completed a 25-min warm-up followed by 9 min of high-intensity rugby-specific training followed by a rugby-specific repeated-sprint test (RSRST). Whole-blood samples were collected to determine lactate and bicarbonate concentrations and pH at baseline, after supplement ingestion, and immediately after the RSRST. Acute GI discomfort was assessed by questionnaire throughout the trials, and chronic GI discomfort was assessed during the 24 hr postingestion. After supplement ingestion and immediately after the RSRST, blood HCO₃⁻ concentration and pH were higher for the NaHCO₃ condition than for the placebo condition (p < .001). After the RSRST, blood lactate concentrations were significantly higher for the NaHCO₃ than for the placebo condition (p < .001). There was no difference in performance on the RSRST between the 2 conditions. The incidence of belching, stomachache, diarrhea, stomach bloating, and nausea was higher after ingestion of NaHCO₃ than with placebo (all p < .050). The severity of stomach cramps, belching, stomachache, bowel urgency, diarrhea, vomiting, stomach bloating, and flatulence was rated worse after ingestion of NaHCO₃ than with placebo (p < .050). NaHCO₃ supplementation increased blood HCO₃⁻ concentration and attenuated the decline in blood pH compared with placebo during high-intensity exercise in well-trained rugby players but did not significantly improve exercise performance. The higher incidence and greater severity of GI symptoms after ingestion of NaHCO₃ may negatively affect

  15. Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents

    International Nuclear Information System (INIS)

    Saucier, Caroline; Adebayo, Matthew A.; Lima, Eder C.; Cataluña, Renato; Thue, Pascal S.; Prola, Lizie D.T.; Puchana-Rosero, M.J.; Machado, Fernando M.; Pavan, Flavio A.; Dotto, G.L.

    2015-01-01

    Highlights: • Microwave-assisted cocoa shell activated carbon was prepared and characterized. • The anti-inflammatories, diclofenac and nimesulide, were adsorbed onto MWCS-1.0. • Adsorption maximum values are 63.47 (diclofenac) and 74.81 mg g −1 (nimesulide). • General order kinetic model suitably explained the adsorption process. • MWCS-1.0 was effectively used for treatment of simulated hospital effluents. - Abstract: Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L −1 HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N 2 adsorption/desorption curves, X-ray diffraction, and point of zero charge (pH pzc ). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g −1 , respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations

  16. Effects of Jerusalem Artichoke Powder and Sodium Carbonate as Phosphate Replacers on the Quality Characteristics of Emulsified Chicken Meatballs.

    Science.gov (United States)

    Öztürk, Burcu; Serdaroğlu, Meltem

    2018-02-01

    Today incorporation of natural ingredients as inorganic phosphate replacers has come into prominence as a novel research topic due to health concerns about phosphates. In this study, we aimed to investigate the quality of emulsified chicken meatballs produced with Jerusalem artichoke powder (JAP), either alone or in combination with sodium carbonate (SC) as sodium tripolyphosphate (STPP) replacers. The results showed that naturally dried JAP showed favorable technological properties in terms of water-oil binding and gelling. Emulsion batters formulated with JAP-SC mixture showed lower jelly and fat separation, higher water-holding capacity and higher emulsion stability than control samples with STPP. In final product, incorporation of JAP-SC mixture increased moisture and reduced lipid and energy values, and kept the pH value similar to control. Added JAP lead to increments in b* values whereas decreases L* values. Cook yield was similar to control in phosphate-free samples formulated with JAP-SC mix. Either low or medium ratios of JAP in combination with SC managed to protect most of the sensory parameters, while sensory scores tend to decrease in samples containing high levels of JAP. Addition of JAP to formulations presented samples that have equivalent behavior to phosphates in terms of lipid oxidation. In conclusion, our study confirms that utilization of JAP in combination with SC had promising effects as phosphate replacers by presenting natural solutions and providing equivalent quality to standard phosphate containing products.

  17. Transport activity of the sodium bicarbonate cotransporter NBCe1 is enhanced by different isoforms of carbonic anhydrase.

    Directory of Open Access Journals (Sweden)

    Christina Schueler

    Full Text Available Transport metabolons have been discussed between carbonic anhydrase II (CAII and several membrane transporters. We have now studied different CA isoforms, expressed in Xenopus oocytes alone and together with the electrogenic sodium bicarbonate cotransporter 1 (NBCe1, to determine their catalytic activity and their ability to enhance NBCe1 transport activity. pH measurements in intact oocytes indicated similar activity of CAI, CAII and CAIII, while in vitro CAIII had no measurable activity and CAI only 30% of the activity of CAII. All three CA isoforms increased transport activity of NBCe1, as measured by the transport current and the rate of intracellular sodium rise in oocytes. Two CAII mutants, altered in their intramolecular proton pathway, CAII-H64A and CAII-Y7F, showed significant catalytic activity and also enhanced NBCe1 transport activity. The effect of CAI, CAII, and CAII mutants on NBCe1 activity could be reversed by blocking CA activity with ethoxyzolamide (EZA, 10 µM, while the effect of the less EZA-sensitive CAIII was not reversed. Our results indicate that different CA isoforms and mutants, even if they show little enzymatic activity in vitro, may display significant catalytic activity in intact cells, and that the ability of CA to enhance NBCe1 transport appears to depend primarily on its catalytic activity.

  18. Some observations on the carburization of type 316 stainless steel foil in a low carbon activity sodium environment

    International Nuclear Information System (INIS)

    Thorley, A.W.; Jeffcoat, P.J.

    1982-01-01

    Work currently being undertaken to establish the equilibrium composition of carbides which form in stainless steel foils during their exposure to low carbon activity sodium environment is described. The time it takes the carbon to reach equilibrium during exposure to sodium of different carbon activity is discussed. The lowest carbon activity measureable in test loops where the sodium is just above carburizing to stainless steel is reported. Analytical techniques are used to determine the composition of the carbide and the austenite matrix and hence estimate the carbon activity of the equilibrium structure. This provides a comparison with carbon activity values determined by alternative methods such as the Harwell Carbon Meter and nickel tab techniques

  19. Dielectrophoresis Aligned Single-Walled Carbon Nanotubes as pH Sensors

    Directory of Open Access Journals (Sweden)

    Wei Xue

    2011-01-01

    Full Text Available Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs. The SWNTs are dispersed in deionized (DI water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with “teeth”-like patterns—fabricated with photolithography and wet etching—are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to deposit and align in desired locations. The device fabrication is inexpensive, solution-based, and conducted at room temperature. The devices are used as pH sensors with the electrodes as the testing pads and the dielectrophoretically captured SWNTs as the sensing elements. When exposed to aqueous solutions with various pH values, the SWNTs change their resistance accordingly. The SWNT-based sensors demonstrate a linear relationship between the sensor resistance and the pH values in the range of 5–9. The characterization of multiple sensors proves that their pH sensitivity is highly repeatable. The real-time data acquisition shows that the sensor response time depends on the pH value, ranging from 2.26 s for the pH-5 solution to 23.82 s for the pH-9 solution. The long-term stability tests illustrate that the sensors can maintain their original sensitivity for a long period of time. The simple fabrication process, high sensitivity, and fast response of the SWNT-based sensors facilitate their applications in a wide range of areas.

  20. Dielectrophoresis Aligned Single-Walled Carbon Nanotubes as pH Sensors.

    Science.gov (United States)

    Li, Pengfei; Martin, Caleb M; Yeung, Kan Kan; Xue, Wei

    2011-01-31

    Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs). The SWNTs are dispersed in deionized (DI) water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with "teeth"-like patterns-fabricated with photolithography and wet etching-are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to deposit and align in desired locations. The device fabrication is inexpensive, solution-based, and conducted at room temperature. The devices are used as pH sensors with the electrodes as the testing pads and the dielectrophoretically captured SWNTs as the sensing elements. When exposed to aqueous solutions with various pH values, the SWNTs change their resistance accordingly. The SWNT-based sensors demonstrate a linear relationship between the sensor resistance and the pH values in the range of 5-9. The characterization of multiple sensors proves that their pH sensitivity is highly repeatable. The real-time data acquisition shows that the sensor response time depends on the pH value, ranging from 2.26 s for the pH-5 solution to 23.82 s for the pH-9 solution. The long-term stability tests illustrate that the sensors can maintain their original sensitivity for a long period of time. The simple fabrication process, high sensitivity, and fast response of the SWNT-based sensors facilitate their applications in a wide range of areas.

  1. Adsorption of cadmium by activated carbon cloth: influence of surface oxidation and solution pH.

    Science.gov (United States)

    Rangel-Mendez, J R; Streat, M

    2002-03-01

    The surface of activated carbon cloth (ACC), based on polyacrylonitrile fibre as a precursor, was oxidised using nitric acid, ozone and electrochemical oxidation to enhance cadmium ion exchange capacity. Modified adsorbents were physically and chemically characterised by pH titration, direct titration, X-ray photoelectron spectroscopy, elemental analysis, surface area and porosimetry, and scanning electron microscopy. BET surface area decreased after oxidation, however, the total ion exchange capacity increased by a factor of approximately 3.5 compared to the commercial as-received ACC. A very significant increase in cadmium uptake, by a factor of 13, was observed for the electrochemically oxidised ACC. Equilibrium sorption isotherms were determined at pH 4, 5 and 6 and these showed that cadmium uptake increased with increasing pH. There was clear evidence of physical damage to ozone-oxidised fibre, however, acid and electrochemically oxidised samples were completely stable.

  2. Biochar alters microbial community and carbon sequestration potential across different soil pH.

    Science.gov (United States)

    Sheng, Yaqi; Zhu, Lizhong

    2018-05-01

    Biochar application to soil has been proposed for soil carbon sequestration and global warming mitigation. While recent studies have demonstrated that soil pH was a main factor affecting soil microbial community and stability of biochar, little information is available for the microbiome across different soil pH and the subsequently CO 2 emission. To investigate soil microbial response and CO 2 emission of biochar across different pH levels, comparative incubation studies on CO 2 emission, degradation of biochar, and microbial communities in a ferralsol (pH5.19) and a phaeozems (pH7.81) with 4 biochar addition rates (0.5%, 1.0%, 2.0%, 5.0%) were conducted. Biochar induced higher CO 2 emission in acidic ferralsol, largely due to the higher biochar degradation, while the more drastic negative priming effect (PE) of SOC resulted in decreased total CO 2 emission in alkaline phaeozems. The higher bacteria diversity, especially the enrichment of copiotrophic bacteria such as Bacteroidetes, Gemmatimonadetes, and decrease of oligotrophic bacteria such as Acidobacteria, were responsible for the increased CO 2 emission and initial positive PE of SOC in ferralsol, whereas biochar did not change the relative abundances of most bacteria at phylum level in phaeozems. The relative abundances of other bacterial taxa (i.e. Actinobacteria, Anaerolineae) known to degrade aromatic compounds were also elevated in both soils. Soil pH was considered to be the dominant factor to affect CO 2 emission by increasing the bioavailability of organic carbon and abundance of copiotrophic bacteria after biochar addition in ferralsol. However, the decreased bioavailability of SOC via adsorption of biochar resulted in higher abundance of oligotrophic bacteria in phaeozems, leading to the decrease in CO 2 emission. Copyright © 2017. Published by Elsevier B.V.

  3. Inactivation of Foot-and-Mouth Disease Virus by Citric Acid and Sodium Carbonate with Deicers

    Science.gov (United States)

    Hong, Jang-Kwan; You, Su-Hwa; Kim, Su-Mi; Tark, Dongseob; Lee, Hyang-Sim; Ko, Young-Joon; Seo, Min-Goo; Park, Jong-Hyeon; Kim, Byounghan

    2015-01-01

    Three out of five outbreaks of foot-and-mouth disease (FMD) since 2010 in the Republic of Korea have occurred in the winter. At the freezing temperatures, it was impossible to spray disinfectant on the surfaces of vehicles, roads, and farm premises because the disinfectant would be frozen shortly after discharge and the surfaces of the roads or machines would become slippery in cold weather. In this study, we added chemical deicers (ethylene glycol, propylene glycol, sodium chloride, calcium chloride, ethyl alcohol, and commercial windshield washer fluid) to keep disinfectants (0.2% citric acid and 4% sodium carbonate) from freezing, and we tested their virucidal efficacies under simulated cold temperatures in a tube. The 0.2% citric acid could reduce the virus titer 4 logs at −20°C with all the deicers. On the other hand, 4% sodium carbonate showed little virucidal activity at −20°C within 30 min, although it resisted being frozen with the function of the deicers. In conclusion, for the winter season, we may recommend the use of citric acid (>0.2%) diluted in 30% ethyl alcohol or 25% sodium chloride solvent, depending on its purpose. PMID:26319879

  4. Inactivation of foot-and-mouth disease virus by citric acid and sodium carbonate with deicers.

    Science.gov (United States)

    Hong, Jang-Kwan; Lee, Kwang-Nyeong; You, Su-Hwa; Kim, Su-Mi; Tark, Dongseob; Lee, Hyang-Sim; Ko, Young-Joon; Seo, Min-Goo; Park, Jong-Hyeon; Kim, Byounghan

    2015-11-01

    Three out of five outbreaks of foot-and-mouth disease (FMD) since 2010 in the Republic of Korea have occurred in the winter. At the freezing temperatures, it was impossible to spray disinfectant on the surfaces of vehicles, roads, and farm premises because the disinfectant would be frozen shortly after discharge and the surfaces of the roads or machines would become slippery in cold weather. In this study, we added chemical deicers (ethylene glycol, propylene glycol, sodium chloride, calcium chloride, ethyl alcohol, and commercial windshield washer fluid) to keep disinfectants (0.2% citric acid and 4% sodium carbonate) from freezing, and we tested their virucidal efficacies under simulated cold temperatures in a tube. The 0.2% citric acid could reduce the virus titer 4 logs at -20°C with all the deicers. On the other hand, 4% sodium carbonate showed little virucidal activity at -20°C within 30 min, although it resisted being frozen with the function of the deicers. In conclusion, for the winter season, we may recommend the use of citric acid (>0.2%) diluted in 30% ethyl alcohol or 25% sodium chloride solvent, depending on its purpose. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Adsorption of phenol by activated carbon: Influence of activation methods and solution pH

    International Nuclear Information System (INIS)

    Beker, Ulker; Ganbold, Batchimeg; Dertli, Halil; Guelbayir, Dilek Duranoglu

    2010-01-01

    Cherry stone based activated carbon derived from a canning industry was evaluated for its ability to remove phenol from an aqueous solution in a batch process. A comparative adsorption on the uptake of phenol by using commercial activated carbon (Chemviron CPG-LF), and two non-functional commercial polymeric adsorbents (MN-200 and XAD-2) containing a styrene-divinylbenzene macroporous hyperreticulated network have been also examined. Equilibrium studies were conducted in 25 mg L -1 initial phenol concentrations, 6.5-9 solution pH and at temperature of 30 deg. C. The experimental data were analyzed by the Langmuir and Freundlich isotherm models. Besides, the cherry stone based activated carbons were carried out by using zinc chloride and KOH activation agents at different chemical ratios (activating agent/precursor), to develop carbons with well-developed porosity. The cherry stone activated carbon prepared using KOH as a chemical agent showed a high surface area. According to the results, activated carbons had excellent adsorptive characteristics in comparison with polymeric sorbents and commercial activated carbon for the phenol removal from the aqueous solutions.

  6. Activated carbons as potentially useful non-nutritive additives to prevent the effect of fumonisin B1 on sodium bentonite activity against chronic aflatoxicosis.

    Science.gov (United States)

    Monge, María Del Pilar; Magnoli, Alejandra Paola; Bergesio, Maria Virginia; Tancredi, Nestor; Magnoli, Carina E; Chiacchiera, Stella Maris

    2016-06-01

    Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins that often co-occur in feedstuffs. The ingestion of AFB1 causes aflatoxicosis in humans and animals. Sodium bentonite (NaB), a cheap non-nutritive unselective sequestering agent incorporated in animal diets, can effectively prevent aflatoxicosis. Fumonisins are responsible for equine leukoencephalomalacia and porcine pulmonary oedema, and often have subclinical toxic effects in poultries. Fumonisin B1 and aflatoxin B1 are both strongly adsorbed in vitro on sodium bentonite. Co-adsorption studies, carried out with a weight ratio of FB1 to AFB1 that mimics the natural occurrence (200:1), showed that FB1 greatly decreases the in vitro ability of NaB to adsorb AFB1. The ability of two activated carbons to adsorb FB1 was also investigated. Both carbons showed high affinity for FB1. A complex behaviour of the FB1 adsorption isotherms with pH was observed. In vitro results suggest that under natural contamination levels of AFB1 and FB1, a mixture of activated carbon and sodium bentonite might be potentially useful for prevention of sub-acute aflatoxicosis.

  7. One-step microwave synthesis of photoluminescent carbon nanoparticles from sodium dextran sulfate water solution

    Science.gov (United States)

    Kokorina, Alina A.; Goryacheva, Irina Y.; Sapelkin, Andrei V.; Sukhorukov, Gleb B.

    2018-04-01

    Photoluminescent (PL) carbon nanoparticles (CNPs) have been synthesized by one-step microwave irradiation from water solution of sodium dextran sulfate (DSS) as the sole carbon source. Microwave (MW) method is very simple and cheap and it provides fast synthesis of CNPs. We have varied synthesis time for obtaining high luminescent CNPs. The synthesized CNPs exhibit excitation-dependent photoluminescent. Final CNPs water solution has a blue- green luminescence. CNPs have low cytotoxicity, good photostability and can be potentially suitable candidates for bioimaging, analysis or analytical tests.

  8. Room temperature synthesis of glycerol carbonate catalyzed by spray dried sodium aluminate microspheres

    OpenAIRE

    Sreerangappa, Ramesh; Debecker, Damien P.

    2017-01-01

    Nanostructured NaAlO2 microspheres are produced from an aqueous solution, by a one-pot spray drying route. The obtained solids are composed of spherical aggregates of sodium aluminate with small crystallite size and strong surface basicity. This makes them highly active catalysts in the base-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The new catalyst does not leach and is recyclable. NaAlO2 microspheres outcompete commercially available NaAlO2 as well as o...

  9. Recent Progress in Design of Biomass-Derived Hard Carbons for Sodium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Joanna Górka

    2016-12-01

    Full Text Available Sodium ion batteries (SIBs have attracted lots of attention over last few years due to the abundance and wide availability of sodium resources, making SIBs the most cost-effective alternative to the currently used lithium ion batteries (LIBs. Many efforts are underway to find effective anodes for SIBs since the commercial anode for LIBs, graphite, has shown very limited capacity for SIBs. Among many different types of carbons, hard carbons—especially these derived from biomass—hold a great deal of promise for SIB technology thanks to their constantly improving performance and low cost. The main scope of this mini-review is to present current progress in preparation of negative electrodes from biomass including aspects related to precursor types used and their impact on the final carbon characteristics (structure, texture and composition. Another aspect discussed is how certain macro- and microstructure characteristics of the materials translate to their performance as anode for Na-ion batteries. In the last part, current understanding of factors governing sodium insertion into hard carbons is summarized, specifically those that could help solve existing performance bottlenecks such as irreversible capacity, initial low Coulombic efficiency and poor rate performance.

  10. Clinical findings and effect of sodium hydrogen carbonate in patients with glutathione synthetase deficiency.

    Science.gov (United States)

    Gündüz, Mehmet; Ünal, Özlem; Kavurt, Sumru; Türk, Emrecan; Mungan, Neslihan Önenli

    2016-04-01

    Glutathione synthetase (GS) deficiency is a rare inborn error of glutathione (GSH) metabolism manifested by severe metabolic acidosis, hemolytic anemia, neurological problems and massive excretion of pyroglutamic acid (5-oxoproline) in the urine. The disorder has mild, moderate, and severe clinical variants. We aimed to report clinical and laboratory findings of four patients, effect of sodium hydrogen carbonate treatment and long-term follow up of three patients. Urine organic acid analysis was performed with gas chromatography-mass spectrometry. Molecular genetic analysis was performed in three patients, mutation was found in two of them. Enzyme analysis was performed in one patient. Clinical and laboratory findings of four patients were evaluated. One patient died at 4 months old, one patient's growth and development are normal, two patients have developed intellectual disability and seizures in the long term follow up period. Three patients benefited from sodium hydrogen carbonate treatment. The clinical picture varies from patient to patient, so it is difficult to predict the prognosis and the effectiveness of treatment protocols. We reported long term follow up of four patients and demonstrated that sodium hydrogen carbonate is effective for treatment of chronic metabolic acidosis in GS deficieny.

  11. Integrated carbon nanospheres arrays as anode materials for boosted sodium ion storage

    Directory of Open Access Journals (Sweden)

    Wangjia Tang

    2018-01-01

    Full Text Available Developing cost-effective advanced carbon anode is critical for innovation of sodium ion batteries. Herein, we develop a powerful combined method for rational synthesis of free-standing binder-free carbon nanospheres arrays via chemical bath plus hydrothermal process. Impressively, carbon spheres with diameters of 150–250 nm are randomly interconnected with each other forming highly porous arrays. Positive advantages including large porosity, high surface and strong mechanical stability are combined in the carbon nanospheres arrays. The obtained carbon nanospheres arrays are tested as anode material for sodium ion batteries (SIBs and deliver a high reversible capacity of 102 mAh g−1 and keep a capacity retention of 95% after 100 cycles at a current density of 0.25 A g−1 and good rate performance (65 mAh g−1 at a high current density of 2 A g−1. The good electrochemical performance is attributed to the stable porous nanosphere structure with fast ion/electron transfer characteristics.

  12. Effect of ion concentrations on uranium absorption from sodium carbonate solutions

    International Nuclear Information System (INIS)

    Traut, D.E.; El Hazek, N.M.T.; Palmer, G.R.; Nichols, I.L.

    1979-01-01

    The effect of various ion concentrations on uranium absorption from a sodium carbonate solution by a strong-base, anion resin was investigated in order to help assure an adequate uranium supply for future needs. The studies were conducted to improve the recovery of uranium from in situ leach solutions by ion exchange. The effects of carbonate, bicarbonate, chloride, and sulfate ions were examined. Relatively low (less than 5 g/l) concentrations of chloride, sulfate, and bicarbonate were found to be detrimental to the absorption of uranium. High (greater than 10 g/l) carbonate concentrations also adversely affected the uranium absorption. In addition, the effect of initial resin form was investigated in tests of the chloride, carbonate, and bicarbonate forms; resin form was shown to have no effect on the absorption of uranium

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

    Science.gov (United States)

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

    2015-06-16

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

  14. High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate

    KAUST Repository

    Imran, Ali; Bramer, Eddy A.; Seshan, Kulathuiyer; Brem, Gerrit

    2014-01-01

    Performance of a novel alumina-supported sodium carbonate catalyst was studied to produce a valuable bio-oil from catalytic flash pyrolysis of lignocellulosic biomass. Post treatment of biomass pyrolysis vapor was investigated in a catalyst fixed

  15. Comparison of the use of sodium carbonate (washing soda crystals) and apomorphine for inducing emesis in dogs.

    Science.gov (United States)

    Yam, E; Hosgood, G; Smart, L

    2016-12-01

    To describe the use of sodium carbonate and apomorphine in a historical cohort of dogs, compare the occurrence of emesis and report any adverse effects recorded. This historical, observational study included information from medical records of dogs that received an emetic agent. The occurrence of emesis with apomorphine or sodium carbonate was calculated and the association between emesis and agent was explored, with the odds ratio and 95% confidence interval (CI) reported. A non-inferiority analysis of the occurrence of emesis for sodium carbonate was performed against an equivalence range of ±7% of the estimated occurrence of emesis with apomorphine. Owners were emailed a short survey about their dog's health after their visit to the hospital for induced emesis. Records for 787 dogs seen from January 2007 to December 2013 were included. For apomorphine, 382/392 dogs showed emesis (97%, 95% CI 95-100%). For sodium carbonate, 320/395 dogs showed emesis (81%, 95% CI 77-85%), which fell below the equivalence range for apomorphine (97 ± 7%, 90-100%) and was considered inferior. The odds ratio of emesis with apomorphine to sodium carbonate was 9.0 (95% CI 4.6-17.6). Of 18 responses to the survey, 5 reported abnormalities after emesis (3 with sodium carbonate, 2 with apomorphine). The occurrence of emesis with sodium carbonate was high but inferior to apomorphine. However, the advantages of sodium carbonate, including less expense and ease of accession compared with apomorphine, make it a viable choice in emergency medicine. © 2016 Australian Veterinary Association.

  16. Highly Stretchable Potentiometric pH Sensor Fabricated via Laser Carbonization and Machining of Carbon-Polyaniline Composite.

    Science.gov (United States)

    Rahimi, Rahim; Ochoa, Manuel; Tamayol, Ali; Khalili, Shahla; Khademhosseini, Ali; Ziaie, Babak

    2017-03-15

    The development of stretchable sensors has recently attracted considerable attention. These sensors have been used in wearable and robotics applications, such as personalized health-monitoring, motion detection, and human-machine interfaces. Herein, we report on a highly stretchable electrochemical pH sensor for wearable point-of-care applications that consists of a pH-sensitive working electrode and a liquid-junction-free reference electrode, in which the stretchable conductive interconnections are fabricated by laser carbonizing and micromachining of a polyimide sheet bonded to an Ecoflex substrate. This method produces highly porous carbonized 2D serpentine traces that are subsequently permeated with polyaniline (PANI) as the conductive filler, binding material, and pH-sensitive membrane. The experimental and simulation results demonstrate that the stretchable serpentine PANI/C-PI interconnections with an optimal trace width of 0.3 mm can withstand elongations of up to 135% and are robust to more than 12 000 stretch-and-release cycles at 20% strain without noticeable change in the resistance. The pH sensor displays a linear sensitivity of -53 mV/pH (r 2 = 0.976) with stable performance in the physiological range of pH 4-10. The sensor shows excellent stability to applied longitudinal and transverse strains up to 100% in different pH buffer solutions with a minimal deviation of less than ±4 mV. The material biocompatibility is confirmed with NIH 3T3 fibroblast cells via PrestoBlue assays.

  17. Active Control of pH in the Bioculture System Through Carbon Dioxide Control

    Science.gov (United States)

    Monhollon, Luke; Pletcher, David; Hauss, Jessica

    2016-01-01

    For successful cell research, the growth culture environment must be tightly controlled. Deviance from the optimal conditions will mask the desired variable being analyzed or lead to inconstancies in the results. In standard laboratories, technology and procedures are readily available for the reliable control of variables such as temperature, pH, nutrient loading, and dissolved gases. Due to the nature of spaceflight, and the inherent constraints to engineering designs, these same elements become a challenge to maintain at stable values by both automated and manual approaches. Launch mass, volume, and power usage create significant constraints to cell culture systems; nonetheless, innovative solutions for active environmental controls are available. The acidity of the growth media cannot be measured through standard probes due to the degradation of electrodes and reliance on indicators for chromatography. Alternatively, carbon dioxide sensors are capable of monitoring the pH by leveraging the relationship between the partial pressure of carbon dioxide and carbonic acid in solution across a membrane. In microgravity cell growth systems, the gas delivery system can be used to actively maintain the media at the proper acidity by maintaining a suitable gas mixture around permeable tubing. Through this method, launch mass and volume are significantly reduced through the efficient use of the limited gas supply in orbit.

  18. Sodium phthalamates as corrosion inhibitors for carbon steel in aqueous hydrochloric acid solution

    International Nuclear Information System (INIS)

    Flores, Eugenio A.; Olivares, Octavio; Likhanova, Natalya V.; Dominguez-Aguilar, Marco A.; Nava, Noel; Guzman-Lucero, Diego; Corrales, Monica

    2011-01-01

    Highlights: → N-Alkyl-sodium phthalamates as corrosion inhibitors for industry in acidic medium. → Compounds behaved as mixed type inhibitors and followed Langmuir adsorption isotherm. → Efficiencies were proportional to aliphatic chain length and inhibitor concentration. → Iron complexes and chelates with phthalamates contributed to carbon steel protection. - Abstract: Three compounds of N-alkyl-sodium phthalamates were synthesized and tested as corrosion inhibitors for carbon steel in 0.5 M aqueous hydrochloric acid. Tests showed that inhibitor efficiencies were related to aliphatic chain length and dependent on concentration. N-1-n-tetradecyl-sodium phthalamate displayed moderate efficiency against uniform corrosion, 42-86% at 25 deg. C and 25-60% at 40 o C. Tests indicated that compounds behave as mixed type inhibitors where molecular adsorption on steel followed Langmuir isotherm, whereas thermodynamic suggested that a physisorption process occurred. XPS analysis confirmed film formation on surface, where Fe +2 complexes and Fe +2 chelates with phthalamates prevented steel from further corrosion.

  19. Benefits of carbon dioxide as pH reducer in chlorinated indoor swimming pools.

    Science.gov (United States)

    Gomà, Anton; Guisasola, Albert; Tayà, Carlota; Baeza, Juan A; Baeza, Mireia; Bartrolí, Albert; Lafuente, Javier; Bartrolí, Jordi

    2010-06-01

    Carbon dioxide is seldom used as pH reducer in swimming pools. Nevertheless it offers two interesting advantages. First, its use instead of the usual hydrochloric acid avoids the characteristic and serious accident of mixing the disinfectant with that strong acid, which forms a dangerous chlorine gas cloud and, second, it allows the facility to become slightly a depository of that greenhouse gas. This work introduces the experience of using CO(2) as pH reducer in real working swimming pools, showing three more advantages: lower chlorine consumption, lower presence of oxidants in the air above the swimming pool and a diminished formation of trihalomethanes in the swimming pool water. Experiments lasted 4years and they were run in three swimming pools in the Barcelona area, where the conventional system based upon HCl and a system based upon CO(2) were consecutively exchanged.

  20. Adsorption of a reactive dye on chemically modified activated carbons--influence of pH.

    Science.gov (United States)

    Orfão, J J M; Silva, A I M; Pereira, J C V; Barata, S A; Fonseca, I M; Faria, P C C; Pereira, M F R

    2006-04-15

    The surface chemistry of a commercial activated carbon with a slightly basic nature was modified by appropriate treatments in order to obtain two additional samples, respectively with acidic and basic properties, without changing its textural parameters significantly. Different techniques (N2 adsorption at 77 K, temperature programmed desorption, and determination of acidity, basicity, and pH at the point of zero charge) were used to characterize the adsorbents. Kinetic and equilibrium adsorption data of a selected textile reactive dye (Rifafix Red 3BN, C.I. reactive red 241) on the mentioned materials were obtained at the pH values of 2, 7, and 12. The kinetic curves are fitted using the second-order model. The respective rate constants seem to diminish progressively with the initial concentration for the more diluted solutions tested, reaching a constant value at higher concentrations, which depends on the experimental system under consideration (adsorbent and pH). In general, the Langmuir model provides the best fit for the equilibrium data. The different uptakes obtained are discussed in relation to the surface chemical properties of the adsorbents. It is shown that the adsorption of the reactive (anionic) dye on the basic sample (prepared by thermal treatment under H2 flow at 700 degrees C) is favored. This conclusion is explained on the basis of the dispersive and electrostatic interactions involved. Moreover, it is also shown that the optimal adsorption condition for all the activated carbons tested corresponds to solution pH values not higher than the pH(pzc) of the adsorbents, which may be interpreted by taking into account the electrostatic forces present.

  1. pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

    Science.gov (United States)

    Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

    2016-10-18

    Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

  2. Stable carbon and nitrogen isotope ratios of sodium and potassium cyanide as a forensic signature.

    Science.gov (United States)

    Kreuzer, Helen W; Horita, Juske; Moran, James J; Tomkins, Bruce A; Janszen, Derek B; Carman, April

    2012-01-01

    Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. Upon analysis, a few of the cyanide samples displayed nonhomogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of the 65 cyanide samples, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples. © 2011 American Academy of Forensic Sciences.

  3. Influence of ph on corrosion control of carbon steel by peroxide injection in sour water

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Martins Magda; Baptista, Walmar; Joia, Carlos Jose Bandeira de Mello [PROTEMP - PETROBRAS/CENPES, Cidade Universitaria, Quadra 7, Rio de Janeiro, CEP 21949-900 (Brazil); Ponciano, Gomes Jose Antonio da Cunha [Departamento de Engenharia Metalurgica e de Materiais-COPPE/UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil)

    2004-07-01

    Sour hydrogen damage is considered the most important corrosive process in the light-ends recovery section of Fluid Catalytic Cracking Units (FCCU). Corrosion in this condition is due to heavy gas oil that originates great amount of contaminants, such as H{sub 2}S, NH{sub 3} and HCN. Hydrogen absorption is promoted by the presence of free cyanides in the environment. The attenuation of this process requires the use of some inhibitors, such as oxygen, hydrogen peroxide (H{sub 2}O{sub 2}) or commercial polysulfides. The effect of these compounds is to neutralize free cyanides (CN{sup -}) into thio-sulfides (SCN{sup -}). When peroxide injection is selected, cyanide concentration in sour water has been used as key parameter to start the peroxide introduction. However, the importance of pH in this system has been pointed out by many authors. The aim of this work is to investigate the influence of pH when peroxide injection is carried out in less alkaline conditions of sour water. Electrochemical techniques - like anodic polarization and hydrogen permeation tests - and weight loss measurements were used to evaluate the effectiveness of corrosion control of carbon steel. It was concluded that at pH 7.5 peroxide injection can drive to an increment of the corrosion rate. Besides that, it was concluded that hydrogen permeation into the metal is promoted. Both detrimental effects were due to elemental sulfur generation in this pH range. The adoption of pH as a key parameter for peroxide injection is then suggested. (authors)

  4. Synthesis of carbon-13 and carbon-14 labeled paldimycin tri-sodium salt

    International Nuclear Information System (INIS)

    Hsi, R.S.P.; Witz, D.F.; Visser, J.; Stolle, W.T.; Ditto, C.L.

    1989-01-01

    Carbon-14 labeled paldimycin trisodium salt was prepared by addition of N-acetyl-L-cysteine to [ 14 C]paulomycin, the radioactive antibiotic produced by fermentation of Streptomyces paulus in the presence of L-methionine labeled with carbon-14 in the S-methyl group. Carbon-13 nuclear magnetic resonance (NMR) spectra of paulomycin produced when the fermentation was carried out in the presence of L-[S-methyl- 13 C]methionine showed that the isotope incorporation had occurred specifically at the methoxy group of ring C, i.e., the 2-deoxy sugar portion of paulomycin. With sustained slow feed of labeled precursors during the optimum antibiotic production period, carbon-14 isotope yields of up to 17.5% with specific activity of up to 11.4 μCi per milligram of paulomycin, and carbon-13 isotope yields of up to 24% with 17-fold isotope enrichment over natural abundance, were achieved. (author)

  5. Reduction of deoxynivalenol in barley by treatment with aqueous sodium carbonate and heat.

    Science.gov (United States)

    Abramson, David; House, James D; Nyachoti, C Martin

    2005-11-01

    Naturally contaminated lots of Canadian barley containing either 18.4 or 4.3 microg/g deoxynivalenol (DON) were heated at 80 degrees C, with small amounts of water or 1 M sodium carbonate solution to study the rate of DON reduction. Samples were heated in sealed polypropylene containers for periods of up to 8 days. In the 18.4 microg/g DON barley, rapid reductions were observed: with no solutions added, DON declined to 14.7 microg/g after 1 day, and to 4.9 microg/g after 8 days solely due to heat; with water at 10 mL/100 g barley, DON levels reached 3.7 microg/g after 8 days; with 1 M sodium carbonate solution added at 10 mL/100 g barley, DON declined to 4.7 microg/g after 1 day, and to 0.4 microg/g after 8 days; with 20 mL/100 g barley, DON declined to 1.4 microg/g after 1 day and to near-zero levels after 8 days. In the 4.3 microg/g DON barley, more gradual reductions were evident: with no solutions added, DON declined to 2.9 microg/g after 8 days solely due to heat; with water at 10 mL/100 g barley, DON levels reached 2.3 microg/g after 8 days; with 1 M sodium carbonate solution added at 10 mL/100 g barley, DON declined to 2.7 microg/g after 1 day, and to near-zero levels after 8 days; with 20 mL/100 g barley, DON declined to 1.4 microg/g after 1 day and to near-zero levels after 3, 5 and 8 days.

  6. Synthesis of carbon-14-labeled sodium palmoxirate and its coenzyme A ester

    Energy Technology Data Exchange (ETDEWEB)

    Weaner, L.E.; Hoerr, D.C.

    1986-04-01

    Synthetic procedures for the preparation of carbon-14-labeled sodium palmoxirate (TDGA), labeled either in the carboxyl position or in the tetradecyl hydrocarbon chain, are described. In addition, the synthesis of the coenzyme A ester of TDGA-14C with a specific activity of 51 mCi/mmol is reported. The coenzyme A ester was prepared by formation of the acyl chloride with oxalyl chloride followed by reaction with coenzyme A (CoA) in a borate-buffered tetrahydrofuran solution. Purification methods and analytical and stability data are reported for the compounds.

  7. Reactive extraction of carboxylic acids from apolar hydrocarbons using aqueous solutions of sodium hydrogen carbonate with back-recovery using carbon dioxide under pressure

    NARCIS (Netherlands)

    Kuzmanovic, B.; Kuipers, N.J.M.; de Haan, A.B.; Kwant, Gerard

    2005-01-01

    A combination of using an aqueous solution of sodium hydrogen carbonate for forward-extraction of carboxylic acids from a dilute apolar organic solvent, and carbon dioxide under pressure for its back-recovery, is studied. Used in combination, these two steps might provide a technique for the

  8. Zinc(II Adsorption by Low-Carbon Shungite: The Effect of pH

    Directory of Open Access Journals (Sweden)

    Axel R. Fischer

    2018-04-01

    Full Text Available Shungite is a carbonaceous rock which is abundant in Karelia (Russian Federation. Large deposits of shungite with low levels of carbon (approx. 10% C are also found in Kazakhstan, where it is mined under the trade name Taurit (Koksu Mining Company. Although Taurit has been reported to be used as an adsorbent for hazardous compounds in water treatment, there is very little precise data about its adsorption capacity or the compounds adsorbed. In this study, the ability of Taurit to adsorb Zn(II was investigated and Freundlich isotherms were determined for both distilled water and tap water. Taurit was found to have a high buffer capacity leading to pH values > 7.0 in aqueous solution. Because dissolved zinc precipitates as Zn(OH2 under alkaline conditions, the pH must be carefully controlled and kept ≤7.0. Despite the small inner surface area (BET of Taurit (13.4 m2 g−1, Freundlich coefficients for distilled water (Kf = 2.4, n = 4.0 and tap water (Kf = 1.5, n = 2.5 were similar to other adsorbents. Our results indicate that Taurit could provide a cheap alternative to activated carbon since both substances have a similar adsorption capacity (at least for Zn(II.

  9. The role of soil pH on soil carbonic anhydrase activity

    Science.gov (United States)

    Sauze, Joana; Jones, Sam P.; Wingate, Lisa; Wohl, Steven; Ogée, Jérôme

    2018-01-01

    Carbonic anhydrases (CAs) are metalloenzymes present in plants and microorganisms that catalyse the interconversion of CO2 and water to bicarbonate and protons. Because oxygen isotopes are also exchanged during this reaction, the presence of CA also modifies the contribution of soil and plant CO18O fluxes to the global budget of atmospheric CO18O. The oxygen isotope signatures (δ18O) of these fluxes differ as leaf water pools are usually more enriched than soil water pools, and this difference is used to partition the net CO2 flux over land into soil respiration and plant photosynthesis. Nonetheless, the use of atmospheric CO18O as a tracer of land surface CO2 fluxes requires a good knowledge of soil CA activity. Previous studies have shown that significant differences in soil CA activity are found in different biomes and seasons, but our understanding of the environmental and ecological drivers responsible for the spatial and temporal patterns observed in soil CA activity is still limited. One factor that has been overlooked so far is pH. Soil pH is known to strongly influence microbial community composition, richness and diversity in addition to governing the speciation of CO2 between the different carbonate forms. In this study we investigated the CO2-H2O isotopic exchange rate (kiso) in six soils with pH varying from 4.5 to 8.5. We also artificially increased the soil CA concentration to test how pH and other soil properties (texture and phosphate content) affected the relationship between kiso and CA concentration. We found that soil pH was the primary driver of kiso after CA addition and that the chemical composition (i.e. phosphate content) played only a secondary role. We also found an offset between the δ18O of the water pool with which CO2 equilibrates and total soil water (i.e. water extracted by vacuum distillation) that varied with soil texture. The reasons for this offset are still unknown.

  10. The role of soil pH on soil carbonic anhydrase activity

    Directory of Open Access Journals (Sweden)

    J. Sauze

    2018-01-01

    Full Text Available Carbonic anhydrases (CAs are metalloenzymes present in plants and microorganisms that catalyse the interconversion of CO2 and water to bicarbonate and protons. Because oxygen isotopes are also exchanged during this reaction, the presence of CA also modifies the contribution of soil and plant CO18O fluxes to the global budget of atmospheric CO18O. The oxygen isotope signatures (δ18O of these fluxes differ as leaf water pools are usually more enriched than soil water pools, and this difference is used to partition the net CO2 flux over land into soil respiration and plant photosynthesis. Nonetheless, the use of atmospheric CO18O as a tracer of land surface CO2 fluxes requires a good knowledge of soil CA activity. Previous studies have shown that significant differences in soil CA activity are found in different biomes and seasons, but our understanding of the environmental and ecological drivers responsible for the spatial and temporal patterns observed in soil CA activity is still limited. One factor that has been overlooked so far is pH. Soil pH is known to strongly influence microbial community composition, richness and diversity in addition to governing the speciation of CO2 between the different carbonate forms. In this study we investigated the CO2–H2O isotopic exchange rate (kiso in six soils with pH varying from 4.5 to 8.5. We also artificially increased the soil CA concentration to test how pH and other soil properties (texture and phosphate content affected the relationship between kiso and CA concentration. We found that soil pH was the primary driver of kiso after CA addition and that the chemical composition (i.e. phosphate content played only a secondary role. We also found an offset between the δ18O of the water pool with which CO2 equilibrates and total soil water (i.e. water extracted by vacuum distillation that varied with soil texture. The reasons for this offset are still unknown.

  11. Influence of pH on the adsorption of uranium ions by oxidized activated carbon and chitosan

    International Nuclear Information System (INIS)

    Park, G.I.; Park, H.S.; Woo, S.I.

    1999-01-01

    The adsorption characteristics of uranyl ions on surface-oxidized carbon were compared with those of powdered chitosan over a wide pH range. In particular, an extensive analysis was made on solution pH variation during the adsorption process or after adsorption equilibrium. Uranium adsorption on the two adsorbents was revealed to be strongly dependent on the initial pH of the solution. A quantitative comparison of the adsorption capacities of the two adsorbents was made, based on the isotherm data obtained at initial pH 3, 4, and 5. In order to analyze the adsorption kinetics incorporated with pH effects, batch experiments at various initial pH values were carried out, and solution pH profiles with the adsorption time were also evaluated. The breakthrough behavior in a column packed with oxidized carbon was also characterized with respect to the variation of effluent pH. Based on these experimental results, the practical applicability of oxidized carbon for uranium removal from acidic radioactive liquid waste was suggested

  12. Scalable and sustainable synthesis of carbon microspheres via a purification-free strategy for sodium-ion capacitors

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Jin, Dongdong; Zhang, Li

    2018-03-01

    Sodium-based energy storage receives a great deal of interest due to the virtually inexhaustible sodium reserve, while the scalable and sustainable strategies to synthesize carbon-based materials with suitable interlayer spaces and large sodium storage capacities are yet to be fully investigated. Carbon microspheres, with regular geometry, non-graphitic characteristic, and stable nature are promising candidates, yet the synthetic methods are usually complex and energy consuming. In this regard, we report a scalable purification-free strategy to synthesize carbon microspheres directly from 5 species of fresh juice. As-synthesized carbon microspheres exhibit dilated interlayer distance of 0.375 nm and facilitate Na+ uptake and release. For example, such carbon microsphere anodes have a specific capacity of 183.9 mAh g-1 at 50 mA g-1 and exhibit ultra-stability (99.0% capacity retention) after 10000 cycles. Moreover, via facile activation, highly porous carbon microsphere cathodes are fabricated and show much higher energy density at high rate than commercial activated carbon. Coupling the compelling anodes and cathodes above, novel sodium-ion capacitors show the high working potential up to 4.0 V, deliver a maximum energy density of 52.2 Wh kg-1, and exhibit an acceptable capacity retention of 85.7% after 2000 cycles.

  13. Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

    Science.gov (United States)

    He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

    2017-10-27

    Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

  14. Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium

    International Nuclear Information System (INIS)

    Afkhami, Abbas; Bahiraei, Atousa; Madrakian, Tayyebeh

    2016-01-01

    A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03–200 μmol L −1 . The lower detection limits were found to be 0.02 μmol L −1 . The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. - Highlights: • GCE was modified with multiwalled carbon nanotube and gold nanoparticles. • AuNP/MWCNT/GCE was used for the determination of diclofenac sodium. • Modified electrode was characterized by SEM, EDS and EIS. • The proposed method showed excellent analytical figures of merit. • This sensor was used for the determination of diclofenac sodium in real samples.

  15. Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium

    Energy Technology Data Exchange (ETDEWEB)

    Afkhami, Abbas, E-mail: afkhami@basu.ac.ir; Bahiraei, Atousa; Madrakian, Tayyebeh

    2016-02-01

    A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03–200 μmol L{sup −1}. The lower detection limits were found to be 0.02 μmol L{sup −1}. The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. - Highlights: • GCE was modified with multiwalled carbon nanotube and gold nanoparticles. • AuNP/MWCNT/GCE was used for the determination of diclofenac sodium. • Modified electrode was characterized by SEM, EDS and EIS. • The proposed method showed excellent analytical figures of merit. • This sensor was used for the determination of diclofenac sodium in real samples.

  16. Amorphous Red Phosphorus Embedded in Sandwiched Porous Carbon Enabling Superior Sodium Storage Performances.

    Science.gov (United States)

    Wu, Ying; Liu, Zheng; Zhong, Xiongwu; Cheng, Xiaolong; Fan, Zhuangjun; Yu, Yan

    2018-03-01

    The red P anode for sodium ion batteries has attracted great attention recently due to the high theoretical capacity, but the poor intrinsic electronic conductivity and large volume expansion restrain its widespread applications. Herein, the red P is successfully encapsulated into the cube shaped sandwich-like interconnected porous carbon building (denoted as P@C-GO/MOF-5) via the vaporization-condensation method. Superior cycling stability (high capacity retention of about 93% at 2 A g -1 after 100 cycles) and excellent rate performance (502 mAh g -1 at 10 A g -1 ) can be obtained for the P@C-GO/MOF-5 electrode. The superior electrochemical performance can be ascribed to the successful incorporation of red P into the unique carbon matrix with large surface area and pore volume, interconnected porous structure, excellent electronic conductivity and superior structural stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effects of sodium hypochlorite and high pH buffer solution in electrokinetic soil treatment on soil chromium removal and the functional diversity of soil microbial community

    International Nuclear Information System (INIS)

    Cang Long; Zhou Dongmei; Alshawabkeh, Akram N.; Chen Haifeng

    2007-01-01

    Effects of sodium hypochlorite (NaClO), applied as an oxidant in catholyte, and high pH buffer solution on soil Cr removal and the functional diversity of soil microbial community during enhanced electrokinetic treatments of a chromium (Cr) contaminated red soil are evaluated. Using pH control system to maintain high alkalinity of soil together with the use of NaClO increased the electrical conductivities of soil pore liquid and electroosmotic flux compared with the control (Exp-01). The pH control and NaClO improved the removal of Cr(VI) and total Cr from the soil. The highest removal percentages of soil Cr(VI) and total Cr were 96 and 72%, respectively, in Exp-04 when the pH value of the anolyte was controlled at 10 and NaClO was added in the catholyte. The alkaline soil environment and introduction of NaClO in the soil enhanced the desorption of Cr(VI) from the soil and promoted Cr(III) oxidation to mobile Cr(VI), respectively. However, the elevated pH and introduction of NaClO in the soil, which are necessary for improving the removal efficiency of soil Cr, resulted in a significantly adverse impact on the functional diversity of soil microbial community. It suggests that to assess the negative impact of extreme conditions for enhancing the extraction efficiencies of Cr on the soil properties and function is necessary

  18. EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS; TOPICAL

    International Nuclear Information System (INIS)

    Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

    2001-01-01

    New federal drinking water regulations have been promulgated to restrict the levels of disinfection by-products (DBPs) in finished public water supplies. DBPs are suspected carcinogens and are formed when organic material is partially oxidized by disinfectants commonly used in the water treatment industry. Additional federal mandates are expected in the near future that will also affect public water suppliers with respect to DBPs. These new federal drinking water regulations may require public water suppliers to adjust treatment practices or incorporate additional treatment operations into their existing treatment trains. Many options have been identified, including membrane processes, granular activated carbon, powered activated carbon (PAC), enhanced coagulation and/or softening, and alternative disinfectants (e.g., chlorine dioxide, ozone, and chloramines). Of the processes being considered, PAC appears to offer an attractive benefit-to-cost advantage for many water treatment plants, particularly small systems (those serving fewer than 10,000 customers). PAC has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated DBPs. Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. Activated carbons can be produced from a variety of raw materials, including wood, peat, coconut husks, and numerous types of coal. The Energy and Environmental Research Center (EERC) has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During that study, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon

  19. High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate

    KAUST Repository

    Imran, Ali

    2014-11-01

    Performance of a novel alumina-supported sodium carbonate catalyst was studied to produce a valuable bio-oil from catalytic flash pyrolysis of lignocellulosic biomass. Post treatment of biomass pyrolysis vapor was investigated in a catalyst fixed bed reactor at the downstream of the pyrolysis reactor. In-situ catalytic upgrading of biomass pyrolysis vapor was conducted in an entrained flow pyrolysis reactor by feeding a premixed feedstock of the catalyst and biomass. Na2CO3/gamma-Al2O3 was very effective for de-oxygenation of the pyrolysis liquid and oxygen content of the bio-oil was decreased from 47.5 wt.% to 16.4 wt.%. An organic rich bio-oil was obtained with 5.8 wt.% water content and a higher heating value of 36.1 MJ/kg. Carboxylic acids were completely removed and the bio-oil had almost a neutral pH. This bio-oil of high calorific low, low water and oxygen content may be an attractive fuel precursor. In-situ catalytic upgrading of biomass pyrolysis vapor produced a very similar quality bio-oil compared to post treatment of pyrolysis vapors, and shows the possible application of Na2CO3/gamma-Al2O3 in a commercial type reactor system such as a fluidized bed reactor. (C) 2014 Elsevier B.V. All rights reserved.

  20. Measurement of carbon activity in sodium by Fe-Mn 20% alloy, and by strainless austenitic steel 304L and 316L

    International Nuclear Information System (INIS)

    Oberlin, C.; Saint Paul, P.; Baque, P.; Champeix, L.

    1980-01-01

    Precise knowledge of carbon activity in sodium used as coolant in fast breeder reactors, is essential for continuous survey of carburization-decarburization processes. Carbon activity can be periodically surveyed by measuring the carbon concentration or by hot trap like metal alloy strip placed in sodium loop. In fact, in equilibrium, activity of carbon in sodium is equal to the activity in metal alloy. Thus if the relation between concentration of carbon and it activity in the alloy is known, it is possible to estimate the activity of carbon in sodium. Materials to be used should have high solubility in carbon at the needed temperature. They should quickly attain equilibrium with sodium and they should not contain impurities that can affect the results. Materials chosen according to these criteria were Fe-Mn 20%, stainless austenitic steel AISI 304L and 316L

  1. Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium.

    Science.gov (United States)

    Afkhami, Abbas; Bahiraei, Atousa; Madrakian, Tayyebeh

    2016-02-01

    A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03-200μmolL(-1). The lower detection limits were found to be 0.02μmolL(-1). The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

    Science.gov (United States)

    Li, Dong; Yin, Wan-zhong; Xue, Ji-wei; Yao, Jin; Fu, Ya-feng; Liu, Qi

    2017-07-01

    The effects of carbonate minerals (dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared (FTIR) spectroscopic studies, and X-ray photoelectron spectroscopy (XPS) analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations (Ca2+ and Mg2+) and CO3 2- ions dissolved from dolomite depressed hematite flotation, whereas only the CO3 2- ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca2+, Mg2+, and CO3 2- (HCO3 -) could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.

  3. Effect of pH on turbidity, size, viscosity and the shape of sodium caseinate aggregates with light scattering and rheometry

    OpenAIRE

    Ghorbani Gorji, Sara; Ghorbani Gorji, Elham; Mohammadifar, Mohammad Amin

    2013-01-01

    The characterization of sodium caseinate solutions as a function of pH was determined using titration with HCL through turbidimetry in different concentrations (0.03 wt.%, 0.045 wt.%, 0.06 wt.%, 0.09 wt.%, 0.2 wt.%, and 0.3 wt.%). Additionally, the coupling of slow in situ acidification of the solution and rheometry was utilized to gain deeper insights into pH-induced structural transitions during the self assembly process and particle size distribution analysis have been used to determine th...

  4. Cation modulation of hemoglobin interaction with sodium n-dodecyl sulphate (SDS) iv: magnesium modulation at pH 7.20

    OpenAIRE

    Ali Akbar Moosavi-Movahedi; Ferdinand C. Chilaka; Charles O. Nwamba

    2016-01-01

    We investigate the interaction of Mg2+ (0–2.30 mM) and sodium n-dodecyl sulfate (SDS) with hemoglobins (Hbs) A and S at pH 7.20. SDS was used to model both membranes (0.60 mM SDS) and proteases (5.0 mM SDS). Via UV-visible spectroscopy, second derivative and difference second derivative spectroscopy, we interrogated for difference(s) in the interaction of these ligands with the proteins that can account for the HbS resistance to malaria parasite while been prone to sickling. Our results show ...

  5. Studies on the kinetics of UO2 dissolution in carbonate-bicarbonate medium using sodium hypochlorite as oxidant

    International Nuclear Information System (INIS)

    Sharma, J.N.; Bhattacharya, K.; Swami, R.G.; Tangri, S.K.; Mukherjee, T.K.

    1996-01-01

    The dissolution of UO 2 in carbonate-bicarbonate solutions containing sodium hypochlorite as an oxidant has been investigated. The effect of temperature, sodium hypochlorite concentration and stirring speed was examined. In the temperature range of 303 to 318 K, the leaching reaction displayed linear kinetics. Apparent activation energy obtained from the differential approach was found to be 57 kJ mol -1 . This relatively high activation energy value indicates a chemically controlled behavior of UO 2 dissolution. The order of reaction with respect to sodium hypochlorite concentration was found to be unity. (author). 18 refs., 6 figs

  6. A low cytotoxic and ratiometric fluorescent nanosensor based on carbon-dots for intracellular pH sensing and mapping

    International Nuclear Information System (INIS)

    Du Fangkai; Ming Yunhao; Zeng Fang; Yu Changmin; Wu Shuizhu

    2013-01-01

    Intracellular pH plays a critical role in the function of cells, and its regulation is essential for most cellular processes. In this study, we demonstrate a fluorescence resonance energy transfer (FRET)-based ratiometric pH nanosensor with carbon-dot (CD) as the carrier. The sensor was prepared by covalently linking a pH-sensitive fluorescent dye (fluorescein isothiocyanate, FITC) onto carbon-dot. As the FRET donor, the carbon-dot exhibits bright fluorescence emission as well as λ ex -dependent photoluminescence emission, and a suitable excitation wavelength for the donor (CD) can be chosen to match the energy acceptor (fluorescein moiety). The fluorescein moieties on a CD undergo structural and spectral conversion as the pH changes, affording the nanoplatform a FRET-based pH sensor. The CD-based system exhibits a significant change in fluorescence intensity ratio between pH 4 and 8 with a pK a value of 5.69. It also displays excellent water dispersibility, good spectral reversibility, satisfactory cell permeability and low cytotoxicity. Following the living cell uptake, this nanoplatform with dual-chromatic emissions can facilitate real-time visualization of the pH evolution involved in the endocytic pathway of the nanosensor. This reversible and low cytotoxic fluorescent nanoplatform may be highly valuable in a variety of biological studies, such as endocytic trafficking, endosome/lysosome maturation, and pH regulation in subcellular organelles. (paper)

  7. Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Ashleigh; Phair, Jolene; Benson, John; Meenan, Brian; Davis, James, E-mail: james.davis@ulster.ac.uk

    2014-10-01

    The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population of endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Graphical abstract: The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Highlights: • In situ creation of pH sensitive quinone groups on carbon fibre • Versatile and accessible approach to manufacturing disposable pH sensors • Miniature probe design enables monitoring pH in small volumes. • Detailed surface characterisation of electrochemically modified carbon fibre.

  8. Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors

    International Nuclear Information System (INIS)

    Anderson, Ashleigh; Phair, Jolene; Benson, John; Meenan, Brian; Davis, James

    2014-01-01

    The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population of endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Graphical abstract: The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Highlights: • In situ creation of pH sensitive quinone groups on carbon fibre • Versatile and accessible approach to manufacturing disposable pH sensors • Miniature probe design enables monitoring pH in small volumes. • Detailed surface characterisation of electrochemically modified carbon fibre

  9. Manipulating Adsorption-Insertion Mechanisms in Nanostructured Carbon Materials for High-Efficiency Sodium Ion Storage

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Shen [College of Chemistry and Molecular Sciences, Hubei Key Laboratory of Electrochemical Power Sources, Wuhan University, Wuhan 430072 China; Xiao, Lifen [College of Chemistry, Central China Normal University, Wuhan 430079 China; Pacific Northwest National Laboratory, Richland WA 99352 USA; Sushko, Maria L. [Pacific Northwest National Laboratory, Richland WA 99352 USA; Han, Kee Sung [Pacific Northwest National Laboratory, Richland WA 99352 USA; Shao, Yuyan [Pacific Northwest National Laboratory, Richland WA 99352 USA; Yan, Mengyu [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 China; Liang, Xinmiao [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071 China; Mai, Liqiang [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 China; Feng, Jiwen [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071 China; Cao, Yuliang [College of Chemistry and Molecular Sciences, Hubei Key Laboratory of Electrochemical Power Sources, Wuhan University, Wuhan 430072 China; Ai, Xinping [College of Chemistry and Molecular Sciences, Hubei Key Laboratory of Electrochemical Power Sources, Wuhan University, Wuhan 430072 China; Yang, Hanxi [College of Chemistry and Molecular Sciences, Hubei Key Laboratory of Electrochemical Power Sources, Wuhan University, Wuhan 430072 China; Liu, Jun [Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-05-12

    Hard carbon is one of the most promising anode materials for sodium-ion batteries, but the low coulombic efficiency is still a key barrier. In this paper we synthesized a series of nanostructured hard carbon materials with controlled architectures. Using a combination of in-situ XRD mapping, ex-situ NMR, EPR, electrochemical techniques and simulations, an “adsorption-intercalation” (A-I) mechanism is established for Na ion storage. During the initial stages of Na insertion, Na ions adsorb on the defect sites of hard carbon with a wide adsorption energy distribution, producing a sloping voltage profile. In the second stage, Na ions intercalate into graphitic layers with suitable spacing to form NaCx compounds similar to the Li ion intercalation process in graphite, producing a flat low voltage plateau. The cation intercalation with a flat voltage plateau should be enhanced and the sloping region should be avoided. Guided by this knowledge, non-porous hard carbon material has been developed which has achieved high reversible capacity and coulombic efficiency to fulfill practical application.

  10. Application of sodium carbonate prevents sulphur poisoning of catalysts in automated total mercury analysis

    Science.gov (United States)

    McLagan, David S.; Huang, Haiyong; Lei, Ying D.; Wania, Frank; Mitchell, Carl P. J.

    2017-07-01

    Analysis of high sulphur-containing samples for total mercury content using automated thermal decomposition, amalgamation, and atomic absorption spectroscopy instruments (USEPA Method 7473) leads to rapid and costly SO2 poisoning of catalysts. In an effort to overcome this issue, we tested whether the addition of powdered sodium carbonate (Na2CO3) to the catalyst and/or directly on top of sample material increases throughput of sulphur-impregnated (8-15 wt%) activated carbon samples per catalyst tube. Adding 5 g of Na2CO3 to the catalyst alone only marginally increases the functional lifetime of the catalyst (31 ± 4 g of activated carbon analyzed per catalyst tube) in relation to unaltered catalyst of the AMA254 total mercury analyzer (17 ± 4 g of activated carbon). Adding ≈ 0.2 g of Na2CO3 to samples substantially increases (81 ± 17 g of activated carbon) catalyst life over the unaltered catalyst. The greatest improvement is achieved by adding Na2CO3 to both catalyst and samples (200 ± 70 g of activated carbon), which significantly increases catalyst performance over all other treatments and enables an order of magnitude greater sample throughput than the unaltered samples and catalyst. It is likely that Na2CO3 efficiently sequesters SO2, even at high furnace temperatures to produce Na2SO4 and CO2, largely negating the poisonous impact of SO2 on the catalyst material. Increased corrosion of nickel sampling boats resulting from this methodological variation is easily resolved by substituting quartz boats. Overall, this variation enables an efficient and significantly more affordable means of employing automated atomic absorption spectrometry instruments for total mercury analysis of high-sulphur matrices.

  11. Early Jurassic Carbon and Sodium Sequestration in a CAMP basalt flow

    Science.gov (United States)

    Block, K. A.; Puffer, J. H.

    2017-12-01

    The initial HTQ-type CAMP Orange Mountain Basalt flow, as well as related pillowed flows and the overlying Preakness flows, locally underwent substantial and well documented albitization, chloritization, and sulphate, carbonate, and zeolite mineralization. Layers representing at least 25 vol % of the Orange Mountain Basalt have undergone a major net increase in sodium and carbon content and a major redistribution of magnesium and calcium. Most alteration occurred during the development of a widespread early Jurassic geothermal system similar to the active system of Iceland. In both cases alteration was controlled by active circulation of basin brines through vesicular layers during rapid burial at temperatures that were kept elevated by recurring magmatism. Whole rock Na2O levels typically increased from 2.2 wt. % in unaltered layers to 3.2 wt. % in vesicular layers, and commonly reached levels exceeding 5 wt. %. The environmental implications of the removal of such massive amounts of sodium from the geothermal system on the chlorine budget and the salt content of Early Jurassic lakes are currently being evaluated. Massive amounts of carbon sequestration from the geothermal system may have mitigated an increased burden on the early Jurassic atmosphere where geothermal CO2 may have otherwise been vented at hot springs or solfataras. Calcite amygdules typically account for 5 to 10 vol. % of the vesiculated layers amounting to 66 to 132 kg of CO2 per m3 of basalt. If 25 vol. % of the 160 thick Orange Mountain Basalt is vesiculated that would equate to about 2640 to 5280 kg of CO2 per m2 of basalt. The full extent of calcite enrichment across the entire CAMP province, however, has not yet been determined.

  12. Selective entrapment of the cationic form of norfloxacin within anionic sodium dodecyl sulfate micelles at physiological pH and its effect on the drug photodecomposition.

    Science.gov (United States)

    Sortino, Salvatore

    2006-01-01

    The binding of the photosensitizing fluoroquinolone (FQ) antibiotic norfloxacin (NX) to sodium dodecyl sulfate (SDS) micelles and the photoreactivity of the NX/SDS complex under physiological pH conditions are investigated by means of absorption and emission spectroscopy, steady-state and laser flash photolysis. It is shown that the photolabile zwitterionic form of NX, which is dominant at physiological pH, is not the most abundant species in the presence of SDS micelles. This medium exhibits a high preference for the cationic form of the drug, which is selectively and successfully entrapped within the micellar cage (K(ass) = 6 x 10(4) M(-1) +/- 3000), becoming the largely dominant species at neutral pH. The effect of this trapping is drastically reflected on both efficiency and nature of the drug photodecomposition. It is observed that the photostability of NX incorporated in the micellar pseudophase increases of more than one order of magnitude if compared to that of the "free" drug. Furthermore, the radical photodecomposition mechanism occurring in phosphate buffered solution is suppressed by the micellar medium and the low photodegradation observed seems to take place preferentially through an ionic pathway. Hopefully, the results presented herein may contribute to a better understanding of the bio-distribution of NX in biological systems and provide helpful and stimulating information in order to get the control of FQ photoreactivity under physiological pH conditions.

  13. A pH-, salt- and solvent-responsive carboxymethylcellulose-g-poly(sodium acrylate/medical stone superabsorbent composite with enhanced swelling and responsive properties

    Directory of Open Access Journals (Sweden)

    2011-05-01

    Full Text Available Free-radical graft copolymerization among sodium carboxymethylcellulose (CMC, partially neutralized acrylic acid (NaA, medical stone (MS and crosslinker N,N'-methylene-bis-acrylamide (MBA was performed to prepare new carboxymethylcellulose-g-poly(sodium acrylate/medical stone (CMC-g-PNaA/MS superabsorbent composites. Fourier transform infrared (FTIR spectra, thermogravimetry- differential scanning calorimetry (TG-DSC and field emission scanning electromicrsocopic (FESEM analysis confirmed that NaA had been grafted onto CMC backbone and MS participated in polymerization, and the thermal stability and surface morphologies were improved by the addition of MS. Energy dispersive spectrometer (EDS and elemental map (EM analyses revealed the better distribution of MS in the CMC-g-PNaA matrix. The incorporation of 20 wt% MS clearly enhanced the water absorption by 100% (from 317 to 634 g/g. The developed composites showed enhanced swelling rate and On-Off switching swelling characteristics in various pH solutions, saline solutions and hydrophilic organic solvents, which represented interesting and reversible pH-, saline- and hydrophilic organic solvent-responsive characteristics. In addition, the composite exhibited intriguing time-dependent kinetic swelling properties in various heavy metal solutions.

  14. Sorption of triclosan onto activated carbon, kaolinite and montmorillonite: effects of pH, ionic strength, and humic acid.

    Science.gov (United States)

    Behera, Shishir Kumar; Oh, Seok-Young; Park, Hung-Suck

    2010-07-15

    Sorption of triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in triclosan sorption was 1.2, approximately 4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1x10(-3) to 5x10(-1) M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g(-1) by increasing the HA concentration to 200 mg C L(-1). However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K(ow)=4.76) of triclosan; and (ii) complexation of HA with triclosan. Though triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of triclosan in subsurface environment can still be appreciable. 2010 Elsevier B.V. All rights reserved.

  15. Evaluation of the pH- and Thermal Stability of the Recombinant Green Fluorescent Protein (GFP) in the Presence of Sodium Chloride

    Science.gov (United States)

    Ishii, Marina; Kunimura, Juliana Sayuri; Jeng, Hélio Tallon; Vessoni Penna, Thereza Christina; Cholewa, Olivia

    The thermal stability of recombinant green fluorescent protein (GFP) in sodium chloride (NaCl) solutions at different concentrations, pH, and temperatures was evaluated by assaying the loss of fluorescence intensity as a measure of denaturation. GFP, extracted from Escherichia coli cells by the three-phase partitioning method and purified through a butyl hydrophobic interaction chromatography (HIC) column, was diluted in water for injection (WFI) (pH 6.0-7.0) and in 10 mM buffer solutions (acetate, pH 5.0; phosphate, pH 7.0; and Tris-EDTA, pH 8.0) with 0.9-30% NaCl or without and incubated at 80-95°C. The extent of protein denaturation was expressed as a percentage of the calculated decimal reduction time (D-value). In acetate buffer (pH 4.84 ±0.12), the mean D-values for 90% reduction in GFP fluorescence ranged from 2.3 to 3.6 min, independent of NaCl concentration and temperature. GFP thermal stability diluted in WFI (pH 5.94±0.60) was half that observed in phosphate buffer (pH 6.08±0.60); but in both systems, D-values decreased linearly with increasing NaCl concentration, with D-values (at 80°C) ranging from 3.44, min (WFI) to 6.1 min (phosphate buffer), both with 30% NaCl. However, D-values in Tris-EDTA (pH 7.65±0.17) were directly dependent on the NaCl concentration and 5-10 times higher than D-values for GFP in WFI at 80°C. GFP pH-and thermal stability can be easily monitored by the convenient measure of fluorescence intensity and potentially be used as an indicator to monitor that processing times and temperatures were attained.

  16. Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents

    Energy Technology Data Exchange (ETDEWEB)

    Saucier, Caroline [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Adebayo, Matthew A. [Department of Chemical Sciences, Ajayi Crowther University, Oyo, Oyo State (Nigeria); Lima, Eder C., E-mail: eder.lima@ufrgs.br [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Cataluña, Renato [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Thue, Pascal S. [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Department of Applied Chemistry, University of Ngaoundere, P.O. Box 455, Ngaoundere (Cameroon); Prola, Lizie D.T.; Puchana-Rosero, M.J. [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Machado, Fernando M. [Technology Development Center, Federal University of Pelotas (UFPEL), Pelotas (Brazil); Pavan, Flavio A. [Institute of Chemistry, Federal University of Pampa (UNIPAMPA), Bagé, RS (Brazil); Dotto, G.L. [Chemical Engineering Department, Federal University of Santa Maria (UFSM), Santa Maria, RS (Brazil)

    2015-05-30

    Highlights: • Microwave-assisted cocoa shell activated carbon was prepared and characterized. • The anti-inflammatories, diclofenac and nimesulide, were adsorbed onto MWCS-1.0. • Adsorption maximum values are 63.47 (diclofenac) and 74.81 mg g{sup −1} (nimesulide). • General order kinetic model suitably explained the adsorption process. • MWCS-1.0 was effectively used for treatment of simulated hospital effluents. - Abstract: Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L{sup −1} HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N{sub 2} adsorption/desorption curves, X-ray diffraction, and point of zero charge (pH{sub pzc}). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g{sup −1}, respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations.

  17. Functionalization of carbon nanotubes with a pH-responsive molecule to produce a pH sensor

    International Nuclear Information System (INIS)

    Zhao Liping; Nakayama, Tomonobu; Tomimoto, Hiroyuki; Shingaya, Yoshitaka; Huang Qing

    2009-01-01

    Carbon nanotubes were functionalized with the ratiometric pH-responsive dye molecule 6,8-dihydroxy-1,3-pyrenedisulfonic acid disodium salt, which enabled them to indicate pH values over the range of pH 5.6-8.3. The nanotubes were coated with a layer of electron-donating ZnPc, which strengthened the CNT-dye interaction. The range of pH response is relevant for biological systems, which makes the nanotubes suitable for a wide range of applications within nanobiotechnology.

  18. Turning into carbonate the residual sodium left in BN-350 circuits may alleviate concerns over their long term safe confinement

    International Nuclear Information System (INIS)

    Rahmani, L

    2000-01-01

    After the coolant is drained from the reactor vessel and from the primary and secondary circuits of the BN-350 nuclear power plant, what sodium is left in ponds and films may amount to hundreds of kilograms. For the long term safe storage period which is to follow, preliminary safety analyses (e.g. derived from those made for French sodium cooled reactors) might show that the risks incurred through loss of leaktightness are significant. The ingress of moisture into the circuits would generate, by reaction with the sodium, two undesirable products : sodium hydroxide and hydrogene. Even when considering that water would enter the circuits progressively, so that the heat of the reaction does not give rise to over-pressure, some main risk factors remain. The most promising solution to this challenge appears to be the carbonation of the sodium residues, by progressive diffusion of an appropriate association of carbon dioxyde and water vapour through the inert gaseous medium which fills the circuits. The desired product is porous sodium hydrogenocarbonate

  19. Studies Conducted of Sodium Carbonate Contaminant Found on the Wing Leading Edge and the Nose Cap of the Space Shuttle Orbiter

    Science.gov (United States)

    Jacobson, Nathan S.; Palou, Jaime J.

    2003-01-01

    In early 2001, three of the space shuttle orbiters were found to have a sodium carbonate contaminant on the wing leading edge and nose cap. These parts are made of a reinforced carbon/carbon material protected by silicon carbide (SiC) and a glass coating. The glass coating is known as Type A and is primarily sodium silicate with particles of SiC. NASA Glenn Research Center's Environmental Durability Branch was asked to determine the chemistry of this deposit formation and assess any possible detrimental effects. At low temperatures, the reverse reaction is favorable. Previous studies of the corrosion of glass show that carbon dioxide in the presence of water does form sodium carbonate on sodium silicate glass (ref. 1). It is quite likely that a similar scenario exists for the orbiter wing leading edge. All three orbiters that formed sodium carbonate were exposed to rain. This formation of sodium carbonate was duplicated in the laboratory. The Type A glass, which coats the wing leading edge and nose cap, was made in a freestanding form and exposed to water in two separate experiments. In one set of experiments, the coating was placed in a petri dish filled with water. As the water evaporated, sodium carbonate formed. In another case, water was slowly dripped on the coating and sodium carbonate formed. The sodium carbonate was detected by chemical analysis and, in some cases, xray diffraction showed a hydrated sodium carbonate. The next step was to examine possible detrimental effects of this sodium carbonate. There are three likely scenarios for the sodium carbonate deposit: (1) it may be removed with a simple rinse, (2) it may remain and flow back into the Type A glass after heating during reentry, or (3) it may remain and flow onto unprotected SiC and/or other parts after heating during reentry. The effect of case 1 is to remove the Na2O constituent from the Type A glass, thus decreasing its effectiveness as a sealant. Even so, overall, it is probably the best

  20. Green synthesis of graphitic carbon nitride nanodots using sodium chloride template

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Bo [National University of Defense Technology, College of Science (China); Zou, Xianshuai; Yan, Tingnan; Fei, Junjie [Xiangtan University, College of Chemistry (China); Chu, Zengyong, E-mail: chuzy@nudt.edu.cn [National University of Defense Technology, College of Science (China)

    2016-05-15

    Graphitic carbon nitride (g-C{sub 3}N{sub 4}) nanodots are simply prepared by a thermal treatment of dicyandiamide (DCDA) confined within NaCl templates. Cyano groups are introduced to the nanodots due to the catalytic effect of NaCl. NaCl could facilitate the polymerization of DCDA at lower temperatures, but will promote the decomposition when the temperature is above 550 °C. Thermal treatment at 600 °C for 30 min is the optimal condition for the scalable synthesis of g-C{sub 3}N{sub 4} nanodots with an average diameter of ~9 nm. g-C{sub 3}N{sub 4} nanodots have a higher band gap of 3.1 eV, which can emit bright blue light due to the decreased diameter, the introduction of cyano groups, and the incorporation of some sodium ions. The residue sodium ions and the cyano groups might lead to the local distortion of the graphitic crystals, or act as recombination centers for the enhanced photoluminescence.Graphical Abstract.

  1. Unusual Passivation Ability of Superconcentrated Electrolytes toward Hard Carbon Negative Electrodes in Sodium-Ion Batteries.

    Science.gov (United States)

    Takada, Koji; Yamada, Yuki; Watanabe, Eriko; Wang, Jianhui; Sodeyama, Keitaro; Tateyama, Yoshitaka; Hirata, Kazuhisa; Kawase, Takeo; Yamada, Atsuo

    2017-10-04

    The passivation of negative electrodes is key to achieving prolonged charge-discharge cycling with Na-ion batteries. Here, we report the unusual passivation ability of superconcentrated Na-salt electrolytes. For example, a 50 mol % sodium bis(fluorosulfonyl)amide (NaFSA)/succinonitrile (SN) electrolyte enables highly reversible Na + insertion into a hard carbon negative electrode without any electrolyte additive, functional binder, or electrode pretreatment. Importantly, an anion-derived passivation film is formed via preferential reduction of the anion upon charging, which can effectively suppress further electrolyte reduction. As a structural characteristic of the electrolyte, most anions are coordinated to multiple Na + cations at high concentration, which shifts the lowest unoccupied molecular orbitals of the anions downward, resulting in preferential anion reduction. The present work provides a new understanding of the passivation mechanism with respect to the coordination state of the anion.

  2. Changes in bone sodium and carbonate in metabolic acidosis and alkalosis in the dog

    Science.gov (United States)

    Burnell, James M.

    1971-01-01

    Metabolic acidosis and alkalosis were produced in adult dogs over 5- to 10-day periods. Midtibial cortical bone was analyzed for calcium, sodium, phosphorus, and carbonate. In acidosis bone CO3/Ca decreased 9.5% and bone Na/Ca decreased 6.3%. In alkalosis bone CO3/Ca increased 3.1% and bone Na/Ca increased 3.0%. Previous attempts to account for changes in net acid balance by summation of extra- and intracellular acid-base changes have uniformly resulted in about 40-60% of acid gained or lost being “unaccounted for.” If it is assumed that changes in tibial cortex reflect changes in the entire skeletal system, changes in bone CO3= are sufficiently large to account for the “unaccounted for” acid change without postulating changes in cellular metabolic acid production. PMID:5540172

  3. Kinetic Effect on the Freezing of Ammonium-Sodium-Carbonate-Chloride Brines and Implications for Origin of Ceres' Bright Spots

    Science.gov (United States)

    Hodyss, R. P.; Thomas, E. C.; Vu, T. H.; Johnson, P. V.; Choukroun, M.

    2017-12-01

    Subsurface brines on Ceres containing natrite (Na2CO3) and smaller amounts of NH4Cl or NH4HCO3 have been proposed to reach the dwarf planet's surface from an internal reservoir, where the brines freeze and result in bright spots across Ceres. Kinetically frozen solutions containing the likely constituents of Ceres' subsurface brines (ammonium, sodium, carbonate, and chloride ions) were studied via infrared and micro-Raman spectroscopy, where the flash-frozen mixtures were found to preferentially form ammonium chloride and ammonium bicarbonate, even in sodium-dominated solutions. Additionally, sodium chloride only formed when sodium or chloride (or both) were present in excess in the brine solutions. Raman spectroscopy was further employed to analyze the effect of vacuum exposure on these frozen brines over longer periods of time to simulate the surface conditions of Ceres.

  4. Removal efficiency of methylene blue using activated carbon from waste banana stem: Study on pH influence

    Science.gov (United States)

    Misran, E.; Bani, O.; Situmeang, E. M.; Purba, A. S.

    2018-02-01

    The effort to remove methylene blue in artificial solution had been conducted using adsorption process. The abundant banana stem waste was utilized as activated carbon precursor. This study aimed to analyse the influence of solution pH to removal efficiency of methylene blue using activated carbon from banana stem as adsorbent. Activated carbon from banana stem was obtained by chemical activation using H3PO4 solution. Proximate analysis result showed that the activated carbon has 47.22% of fixed carbon. This value exhibited that banana stem was a potential adsorbent precursor. Methylene blue solutions were prepared at initial concentration of 50 ppm. The influence of solution pH was investigated with the use of 0.2 g adsorbent for 100 mL dye solution. The adsorption was conducted using shaker with at a constant rate of 100 rpm at room temperature for 90 minutes. The results showed that solution pH influenced the adsorption. The activated carbon from banana stem demonstrated satisfying performance since removal efficiencies of methylene blue were higher than 99%.

  5. Application of a fluidized bed reactor charged with aragonite for control of alkalinity, pH and carbon dioxide in marine recirculating aquaculture systems

    Science.gov (United States)

    Paul S Wills, PhD; Pfeiffer, Timothy; Baptiste, Richard; Watten, Barnaby J.

    2016-01-01

    Control of alkalinity, dissolved carbon dioxide (dCO2), and pH are critical in marine recirculating aquaculture systems (RAS) in order to maintain health and maximize growth. A small-scale prototype aragonite sand filled fluidized bed reactor was tested under varying conditions of alkalinity and dCO2 to develop and model the response of dCO2 across the reactor. A large-scale reactor was then incorporated into an operating marine recirculating aquaculture system to observe the reactor as the system moved toward equilibrium. The relationship between alkalinity dCO2, and pH across the reactor are described by multiple regression equations. The change in dCO2 across the small-scale reactor indicated a strong likelihood that an equilibrium alkalinity would be maintained by using a fluidized bed aragonite reactor. The large-scale reactor verified this observation and established equilibrium at an alkalinity of approximately 135 mg/L as CaCO3, dCO2 of 9 mg/L, and a pH of 7.0 within 4 days that was stable during a 14 day test period. The fluidized bed aragonite reactor has the potential to simplify alkalinity and pH control, and aid in dCO2 control in RAS design and operation. Aragonite sand, purchased in bulk, is less expensive than sodium bicarbonate and could reduce overall operating production costs.

  6. Three-dimensional iron sulfide-carbon interlocked graphene composites for high-performance sodium-ion storage

    DEFF Research Database (Denmark)

    Huang, Wei; Sun, Hongyu; Shangguan, Huihui

    2018-01-01

    Three-dimensional (3D) carbon-wrapped iron sulfide interlocked graphene (Fe7S8@C-G) composites for high-performance sodium-ion storage are designed and produced through electrostatic interactions and subsequent sulfurization. The iron-based metal–organic frameworks (MOFs, MIL-88-Fe) interact with...

  7. High quality bio-oil from catalytic flash pyrolysis of lignocellulosic biomass over alumina-supported sodium carbonate

    NARCIS (Netherlands)

    Ali Imran, A.; Bramer, Eduard A.; Seshan, Kulathuiyer; Brem, Gerrit

    2014-01-01

    Performance of a novel alumina-supported sodium carbonate catalyst was studied to produce a valuable bio-oil from catalytic flash pyrolysis of lignocellulosic biomass. Post treatment of biomass pyrolysis vapor was investigated in a catalyst fixed bed reactor at the downstream of the pyrolysis

  8. Effect of Sodium Carbonate Concentrations on the Formation and Mechanism of Regenerated Silk Fibroin Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Hao Dou

    2014-01-01

    Full Text Available Degumming is the first process for the preparation of all silk-based products. In this paper, effect of sodium carbonate concentrations for silk degumming on the formation of electrospun silk fibroin nanofibers was investigated and the reason for the silk electrospinning process was explained for the first time by differences from the microstructure of regenerated silk fibroin. With increasing the sodium carbonate concentration, microstructure both in the aqueous solutions and in the electrospinning solutions transformed from nanofibrils to nanoparticles, leading to obvious changes on rheological property; electrospinning solutions with nanofibrils behaved like the native silk dope and owned remarkably higher viscosity than the solutions with nanoparticles showing very low viscosity. More interestingly, nanofibrils favored the formation of silk nanofibers with ease, and even nanofibers could be electrospun at concentration 2%. However, nanoparticles were completely unable to generate nanofibers at high spinning concentration 8%. Importance of sodium carbonate concentrations is heavily emphasized for impacting the microstructure types and further influencing the electrospinning performance of regenerated silk. Hence, sodium carbonate concentrations provide a controllable choice for the preparation of silk-based electrospun biomaterials with desired properties.

  9. Continuing assessment of the 5 day sodium carbonate-ammonium nitrate extraction assay as an indicator test for silicon fertilizers

    Science.gov (United States)

    The five day sodium carbonate-ammonium nitrate extraction assay has been proposed by the AAFPCO as a standard test to identify fertilizers that provide plant-available Si. A single-lab validation test was previously performed; however, the analysis lacked any correlation to a grow-out study. To do...

  10. Surface chemistry of pyrite during the pre-processing for the flotation in alkaline sodium carbonate medium during uranium ore processing

    International Nuclear Information System (INIS)

    Neudert, A.; Sommer, H.; Schubert, H.

    1991-01-01

    It is often necessary during processing of uranium ore to flotate pyrite at sodium carbonate alkaline pH value caused by the subsequent hydrometallurgical process stages. It was found out by ESCA analyses that the pyrite surface changes chemically prior to the addition of flotation agents. FeS 2 becomes FeO within a few hours in the case of storage in process water; limonite and/or geothite result from pyrite. The copper ions of the activator CuSO 4 are exclusively monovalent on the pyrite surface. The resulting heavy metal xanthogenate is Cu(I) xanthogenate. Conclusions are derived for the flotation practice for the intensification of the reagent regime. (orig./HP) [de

  11. The pH Dependence of Brown Carbon Formation in Maillard Chemistry

    Science.gov (United States)

    Hawkins, L. N.; Welsh, H.; Alexander, M. V.

    2017-12-01

    Secondary organic aerosol (SOA) composes a non-negligible fraction of brown carbon (BrC), and typically appears as small, nitrated aromatics or larger, highly functionalized humic-like substances (HULIS). Both nitrated aromatics and HULIS contain nitrogen, indicating the importance of nitrogen to light-absorbing aerosol. It is therefore unsurprising that BrC, when generated in aqueous phase reactions (aqBrC) between amines and small aldehydes, often resembles atmospheric HULIS. The effects of pH and aqueous phase oxidation on absorptivity and composition were simulated using bulk (microliter) samples under a variety of experimental conditions, including evaporation. The system of amines and small aldehydes included methylamine, ammonium sulfate, glyoxal, and methylglyoxal. Chemical composition of these products was characterized using an Aerosol Chemical Speciation Monitor (ACSM) and a desorption-based atmospheric pressure chemical ionization (APCI) spectrometer. The results of this study indicate that methylamine and methylglyoxal form the most absorptive BrC, cloud processing serves to increase BrC absorptivity, and the generated BrC is highly persistent to oxidative and photodegradation. Lowering the pH to values below 6 reduces absorptivity at shorter wavelengths, but produces a new shoulder beyond 400 nm indicating new chromophore formation. Results of this research also show that evaporation increased formation of large molecular fragments (m/z > 100). Furthermore, the mass spectra showed significant formation of these larger fragments in methylamine systems with little evidence for similar compounds in ammonium sulfate systems. Systems with methylglyoxal had higher absorptivity than all other systems, although in both methylamine and ammonium sulfate systems, glyoxal appeared to result in a higher percentage of large fragments than methylglyoxal. Lastly, hydroxyl radical degradation seemed to have a minimal effect on absorptivity and composition, although

  12. Influence of sodium dodecyl sulfonate (SDS) on the hydrothermal synthesis of YVO4:Eu3+ crystals in a wide pH range

    International Nuclear Information System (INIS)

    Wang Juan; Xu Yunhua; Hojamberdiev, Mirabbos; Zhu Gangqiang

    2009-01-01

    In this work, a facile hydrothermal route has been proposed for the morphology-controllable preparation of Eu-doped yttrium orthovanadate (YVO 4 :Eu 3+ ) powders in the presence of sodium dodecyl sulfonate (SDS) as a template in a wide pH range. The structure, composition, morphology, and optical properties of the final products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL), respectively. It was found that single phase YVO 4 :Eu 3+ micro- and nanocrystals with different shapes can be fabricated at 180 deg. C for 24 h with suitable amount of SDS in a wide pH range. The formation mechanism and the influence of SDS on the morphology of YVO 4 :Eu 3+ micro- and nanocrystals were investigated as a function of pH value. The PL measurement revealed that the samples with different morphologies exhibited different values for optical properties, especially soybean-like nanopowders showed a higher intensity compared to other samples with different morphologies due mainly to their high packing densities and low scattering of light.

  13. Controllable synthesis of green and blue fluorescent carbon nanodots for pH and Cu(2+) sensing in living cells.

    Science.gov (United States)

    Shi, Lihong; Li, Yanyan; Li, Xiaofeng; Zhao, Bo; Wen, Xiangping; Zhang, Guomei; Dong, Chuan; Shuang, Shaomin

    2016-03-15

    We report a controllable strategy for fabrication of green and blue fluorescent carbon nanodots (CDs), and demonstrate their applications for pH and Cu(2+) sensing in living cells. Green and blue fluorescent CDs have been synthesized by hydrothermal method and pyrolysis of leeks, respectively, providing an easy way for the production of CDs without the request of tedious synthetic methodology or the use of toxic/expensive solvents and starting materials. Green fluorescent CDs (G-CDs) exhibit high tolerance to pH values and external cations. Blue fluorescent CDs (B-CDs) can be applied to pH and Cu(2+) sensing. The linear range of Cu(2+) detection is 0.01-10.00 μM and the detection limit is 0.05 μM. For pH detection, there is a good linearity in the pH range of 3.5-10.0. The linear and rapid response of B-CDs to Cu(2+) and pH is valuable for Cu(2+) and pH sensing in living cells. Confocal fluorescent imaging of human cervical carcinoma cells indicates that B-CDs could visualize Cu(2+) and pH fluctuations in living cells with negligible autofluorescence. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Growth limitation of three Arctic sea-ice algae species: effects of salinitty, pH and inorganic carbon availability

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Hansen, Per Juel; Rysgaard, Søren

    2011-01-01

    The effect of salinity, pH, and dissolved inorganic carbon (TCO(2)) on growth and survival of three Arctic sea ice algal species, two diatoms (Fragilariopsis nana and Fragilariopsis sp.), and one species of chlorophyte (Chlamydomonas sp.) was assessed in controlled laboratory experiments. Our res...

  15. Ketoprofen-loaded Eudragit RSPO microspheres: an influence of sodium carbonate on in vitro drug release and surface topology.

    Science.gov (United States)

    Pandit, Sachin S; Hase, Dinesh P; Bankar, Manish M; Patil, Arun T; Gaikwad, Naresh J

    2009-05-01

    Eudragit RSPO microspheres containing ketoprofen as model drug, prepared by solvent evaporation technique using acetone-liquid paraffin (heavy) solvent system were examined. Depending upon polymer concentration in the internal phase, microspheres of particle mean diameter (122.8, 213.6 and 309.5 μm) were obtained. The influence of surface washing of microspheres with n-hexane, i.e. untreated microspheres (UM) on the drug content, drug release and surface topology of microspheres were compared to those of microspheres washed with sodium carbonate, i.e. treated microspheres (TM) in order to make the non-encapsulated surface drug soluble. The significant reduction in encapsulation efficiency (p < 0.001) and drug content (p < 0.001) after treatment, in combination with the small crystalline peaks observed during XRD testing and lack of melting endotherm observed in DSC testing, suggests that the washing process actually removes a significant amount of drug (p < 0.001) from the surface and encapsulated near to the surface of the microsphere polymer matrix. Scanning electron microscopy (SEM) examination revealed that the removal of surface drug did not affect the size of microspheres but the topology of treated smallest microspheres was modified. The ketoprofen release profiles were examined in phosphate buffer pH 7.4, using USPXXIII paddle type dissolution apparatus. In general both UM and TM result in biphasic release patterns, but the initial burst effect (first release phase) of TM was lower than that of UM. The second release phase did not change for the bigger size but increased for the smallest microspheres, probably owing to the modification of matrix porosity.

  16. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    Science.gov (United States)

    Zaini, Mariana Binti Mohd; Badri, Khairiah Haji

    2014-09-01

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber.

  17. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Zaini, Mariana Binti Mohd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Badri, Khairiah Haji [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia and Polymer Research Center, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43 (Malaysia)

    2014-09-03

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber.

  18. Pitting corrosion of lead in sodium carbonate solutions containing NO3- ions

    International Nuclear Information System (INIS)

    Amin, Mohammed A.; Abdel Rehim, Sayed S.

    2004-01-01

    Pitting corrosion of Pb in Na 2 CO 3 solutions (pH=10.8) containing NaNO 3 as a pitting corrosion agent has been studied using potentiodynamic anodic polarization, cyclic voltammetry and chronoamperometry techniques, complemented with scanning electron microscopy (SEM) examinations of the electrode surface. In the absence of NO 3 - , the anodic voltammetric response exhibits three anodic peaks prior to oxygen evolution. The first anodic peak A 1 corresponds to the formation of PbCO 3 layer and soluble Pb 2+ species in solution. The second anodic peak A 2 is due to the formation of PbO beneath the carbonate layer. Peak A 2 is followed by a wide passive region which extends up to the appearance of the third anodic peak A 3 . The later is related to the formation of PbO 2 . Addition of NO 3 - to the carbonate solution stimulates the anodic dissolution through peaks A 1 and A 2 and breaks down the dual passive layer prior to peak A 3 . The breakdown potential decreases with an increase in nitrate concentration, temperature and electrode rotation rate, but increases with an increase in carbonate concentration and potential scan rate. Successive cycling leads to a progressive increase in breakdown potential. The current/time transients show that the incubation time for passivity breakdown decreases with increasing the applied anodic potential, nitrate concentration and temperature

  19. The anodic dissolution of SIMFUEL (UO2) in slightly alkaline sodium carbonate/bicarbonate solutions

    International Nuclear Information System (INIS)

    Keech, P.G.; Goldik, J.S.; Qin, Z.; Shoesmith, D.W.

    2011-01-01

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U VI corrosion product, [UO 2 ] 2+ . As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO 2 ) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U IV → U V → U VI ). At low potentials (≤250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U VI O 2 CO 3 surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  20. pH responsive controlled release of anti-cancer hydrophobic drugs from sodium alginate and hydroxyapatite bi-coated iron oxide nanoparticles.

    Science.gov (United States)

    Manatunga, Danushika C; de Silva, Rohini M; de Silva, K M Nalin; de Silva, Nuwan; Bhandari, Shiva; Yap, Yoke Khin; Costha, N Pabakara

    2017-08-01

    Developing a drug carrier system which could perform targeted and controlled release over a period of time is utmost concern in the pharmaceutical industry. This is more relevant when designing drug carriers for poorly water soluble drug molecules such as curcumin and 6-gingerol. Development of a drug carrier system which could overcome these limitations and perform controlled and targeted drug delivery is beneficial. This study describes a promising approach for the design of novel pH sensitive sodium alginate, hydroxyapatite bilayer coated iron oxide nanoparticle composite (IONP/HAp-NaAlg) via the co-precipitation approach. This system consists of a magnetic core for targeting and a NaAlg/HAp coating on the surface to accommodate the drug molecules. The nanocomposite was characterized using FT-IR spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. The loading efficiency and loading capacity of curcumin and 6-gingerol were examined. In vitro drug releasing behavior of curcumin and 6-gingerol was studied at pH 7.4 and pH 5.3 over a period of seven days at 37°C. The mechanism of drug release from the nanocomposite of each situation was studied using kinetic models and the results implied that, the release is typically via diffusion and a higher release was observed at pH 5.3. This bilayer coated system can be recognized as a potential drug delivery system for the purpose of curcumin and 6-gingerol release in targeted and controlled manner to treat diseases such as cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Fluidized-Bed Coating with Sodium Sulfate and PVA-TiO2, 2. Influence of Coating Solution Viscosity, Stickiness, pH, and Droplet Diameter on Agglomeration

    DEFF Research Database (Denmark)

    Hede, Peter Dybdahl; Bach, Poul; Jensen, Anker Degn

    2009-01-01

    In the first part of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 49, 1914], agglomeration regime maps were developed for two types of coatings: sodium sulfate and PVA-TiO2. It was observed here how the agglomeration tendency is always lower for the salt coating...... the PVA-TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to that of the salt coating process. The best results for the PVA-TiO2 solution are obtained by substituting the PVA-TiO2 in equal amounts with Neodol 23-6.5 and further reducing the pH value in the coating...

  2. Desorption of Reactive Red 198 from activated carbon prepared from walnut shells: effects of temperature, sodium carbonate concentration and organic solvent dose

    Directory of Open Access Journals (Sweden)

    Zohreh Alimohamadi

    2017-04-01

    Full Text Available This study investigated the effect of temperature, different concentrations of sodium carbonate,and the dose of organic solvent on the desorption of Reactive Red 198 dye from dye-saturated activated carbon using batch and continuous systems. The results of the batch desorption test showed 60% acetone in water as the optimum amount. However, when the concentration of sodium carbonate was raised, the dye desorption percentage increased from 26% to 42% due to economic considerations; 15 mg/L of sodium carbonate was selected to continue the processof desorption. Increasing the desorption temperature can improve the dye desorption efficiency.According to the column test results, dye desorption concentration decreased gradually with the passing of time. The column test results showed that desorption efficiency and the percentage of dye adsorbed decreased; however, it seemed to stabilize after three repeated adsorption/desorption cycles. The repeated adsorption–desorption column tests (3 cycles showed that the activated carbon which was prepared from walnut shell was a suitable and economical adsorbent for dye removal.

  3. Intracellular pH homeostasis and serotonin-induced pH changes in Calliphora salivary glands: the contribution of V-ATPase and carbonic anhydrase.

    Science.gov (United States)

    Schewe, Bettina; Schmälzlin, Elmar; Walz, Bernd

    2008-03-01

    Blowfly salivary gland cells have a vacuolar-type H(+)-ATPase (V-ATPase) in their apical membrane that energizes secretion of a KCl-rich saliva upon stimulation with serotonin (5-hydroxytryptamine, 5-HT). We have used BCECF to study microfluometrically whether V-ATPase and carbonic anhydrase (CA) are involved in intracellular pH (pH(i)) regulation, and we have localized CA activity by histochemistry. We show: (1) mean pH(i) in salivary gland cells is 7.5+/-0.3 pH units (N=96), higher than that expected from passive H(+) distribution; (2) low 5-HT concentrations (0.3-3 nmol l(-1)) induce a dose-dependent acidification of up to 0.2 pH units, with 5-HT concentrations >10 nmol l(-1), causing monophasic or multiphasic pH changes; (3) the acidifying effect of 5-HT is mimicked by bath application of cAMP, forskolin or IBMX; (4) salivary gland cells exhibit CA activity; (5) CA inhibition with acetazolamide and V-ATPase inhibition with concanamycin A lead to a slow acidification of steady-state pH(i); (6) 5-HT stimuli in the presence of acetazolamide induce an alkalinization that can be decreased by simultaneous application of the V-ATPase inhibitor concanamycin A; (7) concanamycin A removes alkali-going components from multiphasic 5-HT-induced pH changes; (8) NHE activity and a Cl(-)-dependent process are involved in generating 5-HT-induced pH changes; (9) the salivary glands probably contain a Na(+)-driven amino acid transporter. We conclude that V-ATPase and CA contribute to steady-state pH(i) regulation and 5-HT-induced outward H(+) pumping does not cause an alkalinization of pH(i) because of cytosolic H(+) accumulation attributable to stimulated cellular respiration and AE activity, masking the alkalizing effect of V-ATPase-mediated acid extrusion.

  4. Technical Information on the Carbonation of the EBR-II Reactor, Summary Report Part 1: Laboratory Experiments and Application to EBR-II Secondary Sodium System

    Energy Technology Data Exchange (ETDEWEB)

    Steven R. Sherman

    2005-04-01

    Residual sodium is defined as sodium metal that remains behind in pipes, vessels, and tanks after the bulk sodium metal has been melted and drained from such components. The residual sodium has the same chemical properties as bulk sodium, and differs from bulk sodium only in the thickness of the sodium deposit. Typically, sodium is considered residual when the thickness of the deposit is less than 5-6 cm. This residual sodium must be removed or deactivated when a pipe, vessel, system, or entire reactor is permanently taken out of service, in order to make the component or system safer and/or to comply with decommissioning regulations. As an alternative to the established residual sodium deactivation techniques (steam-and-nitrogen, wet vapor nitrogen, etc.), a technique involving the use of moisture and carbon dioxide has been developed. With this technique, sodium metal is converted into sodium bicarbonate by reacting it with humid carbon dioxide. Hydrogen is emitted as a by-product. This technique was first developed in the laboratory by exposing sodium samples to humidified carbon dioxide under controlled conditions, and then demonstrated on a larger scale by treating residual sodium within the Experimental Breeder Reactor II (EBR-II) secondary cooling system, followed by the primary cooling system, respectively. The EBR-II facility is located at the Idaho National Laboratory (INL) in southeastern Idaho, U.S.A. This report is Part 1 of a two-part report. It is divided into three sections. The first section describes the chemistry of carbon dioxide-water-sodium reactions. The second section covers the laboratory experiments that were conducted in order to develop the residual sodium deactivation process. The third section discusses the application of the deactivation process to the treatment of residual sodium within the EBR-II secondary sodium cooling system. Part 2 of the report, under separate cover, describes the application of the technique to residual sodium

  5. Full color emitting fluorescent carbon material as reversible pH sensor with multicolor live cell imaging.

    Science.gov (United States)

    Sharma, Vinay; Kaur, Navpreet; Tiwari, Pranav; Mobin, Shaikh M

    2018-05-01

    Carbon-based nano materials are developed as a cytocompatible alternative to semiconducting quantum dots for bioimaging and fluorescence-based sensing. The green alternatives for the synthesis of carbon materials are imminent. The present study demonstrates microwave based one step quick synthesis of fluorescent carbon material (FCM) having three variants: (i) un-doped fluorescent carbon material (UFCM) (ii) nitrogen doped FCM (N@FCM), and (iii) nitrogen & phosphorus co-doped FCM (N-P@FCM) using sugarcane extract as a carbon source. The N doping was performed using ethylenediamine and phosphoric acid was used for P doping. The heteroatom doped FCM were synthesized due to insolubility of UFCM in water. Unlike, UFCM, the N@FCM and N-P@FCM were found to be highly soluble in water. The N-P@FCM shows highest quantum yield among the three. The N-P@FCM was explored for alkaline pH sensing and it shows a quenching of fluorescence in the pH range 09-14. The sensing behaviour shows reversibility and high selectivity. Further, the sensor was also investigated for their biocompatibility and hence employed as a promising multicolour probe for cancer cell imaging. The generality in cell imaging was investigated by flow cytometry. The hetero-atom doped green carbon-dots may open new avenues for sensing and selective cellular targeting. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Hydrothermal carbonization (HTC) of wheat straw: influence of feedwater pH prepared by acetic acid and potassium hydroxide.

    Science.gov (United States)

    Reza, M Toufiq; Rottler, Erwin; Herklotz, Laureen; Wirth, Benjamin

    2015-04-01

    In this study, influence of feedwater pH (2-12) was studied for hydrothermal carbonization (HTC) of wheat straw at 200 and 260°C. Acetic acid and KOH were used as acidic and basic medium, respectively. Hydrochars were characterized by elemental and fiber analyses, SEM, surface area, pore volume and size, and ATR-FTIR, while HTC process liquids were analyzed by HPLC and GC. Both hydrochar and HTC process liquid qualities vary with feedwater pH. At acidic pH, cellulose and elemental carbon increase in hydrochar, while hemicellulose and pseudo-lignin decrease. Hydrochars produced at pH 2 feedwater has 2.7 times larger surface area than that produced at pH 12. It also has the largest pore volume (1.1 × 10(-1) ml g(-1)) and pore size (20.2 nm). Organic acids were increasing, while sugars were decreasing in case of basic feedwater, however, phenolic compounds were present only at 260°C and their concentrations were increasing in basic feedwater. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Dissolution of barite for the analysis of strontium isotopes and other chemical and isotopic variations using aqueous sodium carbonate

    Science.gov (United States)

    Breit, G.N.; Simmons, E.C.; Goldhaber, M.B.

    1985-01-01

    A simple procedure for preparing barite samples for chemical and isotopic analysis is described. Sulfate ion, in barite, in the presence of high concentrations of aqueous sodium carbonate, is replaced by carbonate. This replacement forms insoluble carbonates with the cations commonly in barite: Ba, Sr, Ca and Pb. Sulfate is released into the solution by the carbonate replacement and is separated by filtration. The aqueous sulfate can then be reprecipitated for analysis of the sulfur and oxygen isotopes. The cations in the carbonate phase can be dissolved by acidifying the solid residue. Sr can be separated from the solution for Sr isotope analysis by ion-exchange chromatography. The sodium carbonate used contains amounts of Sr which will affect almost all barite 87Sr 86Sr ratios by less than 0.00001 at 1.95?? of the mean. The procedure is preferred over other techniques used for preparing barite samples for the determination of 87Sr 86Sr ratios because it is simple, rapid and enables simultaneous determination of many compositional parameters on the same material. ?? 1985.

  8. The effect of buffering dairy cow diets with limestone, calcareous marine algae, or sodium bicarbonate on ruminal pH profiles, production responses, and rumen fermentation.

    Science.gov (United States)

    Cruywagen, C W; Taylor, S; Beya, M M; Calitz, T

    2015-08-01

    Six ruminally cannulated Holstein cows were used to evaluate the effect of 2 dietary buffers on rumen pH, milk production, milk composition, and rumen fermentation parameters. A high concentrate total mixed ration [35.2% forage dry matter (DM)], formulated to be potentially acidotic, was used to construct 3 dietary treatments in which calcareous marine algae (calcified remains of the seaweed Lithothamnium calcareum) was compared with limestone (control) and sodium bicarbonate plus limestone. One basal diet was formulated and the treatment diets contained either 0.4% of dietary DM as Acid Buf, a calcified marine algae product (AB treatment), or 0.8% of dietary DM as sodium bicarbonate and 0.37% as limestone (BC treatment), or 0.35% of dietary DM as limestone [control (CON) treatment]. Cows were randomly allocated to treatments according to a double 3×3 Latin square design, with 3 treatments and 3 periods. The total experimental period was 66 d during which each cow received each treatment for a period of 15 d before the data collection period of 7 d. Rumen fluid was collected to determine volatile fatty acids, lactic acid, and ammonia concentrations. Rumen pH was monitored every 10min for 2 consecutive days using a portable data logging system fitted with in-dwelling electrodes. Milk samples were analyzed for solid and mineral contents. The effect of treatment on acidity was clearly visible, especially from the period from midday to midnight when rumen pH dropped below 5.5 for a longer period of time (13 h) in the CON treatment than in the BC (8.7 h) and AB (4 h) treatments. Daily milk, 4% fat-corrected milk, and energy-corrected milk yields differed among treatments, with AB being the highest, followed by BC and CON. Both buffers increased milk fat content. Treatment had no effect on milk protein content, but protein yield was increased in the AB treatment. Total rumen volatile fatty acids and acetate concentrations were higher and propionate was lower in the AB

  9. Cation modulation of hemoglobin interaction with sodium n-dodecyl sulphate (SDS iv: magnesium modulation at pH 7.20

    Directory of Open Access Journals (Sweden)

    Ali Akbar Moosavi-Movahedi

    2016-03-01

    Full Text Available We investigate the interaction of Mg2+ (0–2.30 mM and sodium n-dodecyl sulfate (SDS with hemoglobins (Hbs A and S at pH 7.20. SDS was used to model both membranes (0.60 mM SDS and proteases (5.0 mM SDS. Via UV-visible spectroscopy, second derivative and difference second derivative spectroscopy, we interrogated for difference(s in the interaction of these ligands with the proteins that can account for the HbS resistance to malaria parasite while been prone to sickling. Our results show that Mg2+ interaction with the proteins lowered the HbS oxygen affinity in comparison with the HbA. Additionally, [SDS]-protein interactions resulted in oxoferryl heme species formation that was prominent for the HbA and highly diminished for the HbS. [Mg2+] introduction to the [SDS]-protein mixture, however decreased the concentration of denatured protein species. The [Mg2+]-[SDS]-protein interactions suggest that while ionic or coulomb interactions for the HbA, in the presence of the surfactants, are [Mg2+] dependent, those of the HbS are not. Furthermore, hydrophobicity is a crucial force for the HbS interaction at neutral pH and is little-masked by ionic, electrostatic or coulombic interactions. In conclusion, at physiological pH, the Mg-SDS interaction decreased the HbS denaturation in comparison to the HbA.

  10. Uranium recovery by leaching with sodium carbonate at high temperature and pressure

    International Nuclear Information System (INIS)

    Soerensen, E.; Koefoed, S.; Lundgaard, T.

    1983-11-01

    The principal uranium bearing mineral in Greenland steenstrupine is a complex sodium REE phosphosilicate in which Fe, Mn, Th, U are minor constituents. The Na 2 CO 3 extractant is used for specially acidconsuming ores. However, steenstrupine is decomposed by Na 2 CO 3 only at temperatures above 220degC, so the leaching must be carried out under pressure. Laboratory tests have shown the optimal temperature to be 260degC and the leach liquor composition120 g/l of NaHCO 3 and 20 g/l of Na 2 CO 3 . Addition of oxygen is necessary as uranium will not dissolve in carbonate unless it is brought in its highest state of oxidation. According to the laboratory tests it may be estimated that 1 kg of ore suspended in 1 l of leach liquor and ground to 80% minus 200 mesh can be extracted in 20-40 minutes. On the basis of data obtained a process was suggested in which the ore is ground with carbonate leach liquor to a suitable suspension which is fed to an autoclave with a retentiontime of 20 minutes at 260degC. The residue is filtered off and the liquor reused for grinding and ex- traction. The demand for a reaction temperature near 300degC, a pressure up to 120 atm. and a continuos operation favours a tubular flow autoclave with so narrow a bore that the turbulence provides the mechanical agitation of the suspension. From the mined material it appears that more than 80% of the uranium can be extracted in the pipe autoclave. Some samples give off the obtainable uranium in 20 minutes. The precipitated yellow cake is contaminated with more Na and Si than admitted by international standards. (EG)

  11. THE STIMULATING EFFECT OF LASER RED LIGHT, FAR RED LIGHT AND SODIUM CARBONATE AT THE INITIAL STAGES OF BARLEY ONTOGENESIS

    Directory of Open Access Journals (Sweden)

    G. P. Dudin

    2014-01-01

    Full Text Available Summary. Modern ecological state of the environment and human unhealthy diet cause many diseases. A healthy diet is the one that contains adequate amounts of proteins, fats, carbohydrates, vitamins, macronutrients and micronutrients. Photosynthesis i. e. the process by which plants produce organic compounds from carbon dioxide and water, is the source of life, the source of evolution and proliferation of life forms on the Earth. Thus, the juice made from sprouted barley provides physiologically active chlorophyll, macronutrients and micronutrients, vitamins А, В2 , В3 , В5 , В6 , В8 , Е and К. It is well known that light from a red laser with a wavelength of 638.2 nm has a stimulating action on the germination energy, germination ability and productivity of seeds, and on the crop yields. Therefore, this research is of primary importance today. The research result produced a sharp decline in plant vigor and germinating capacity of barley when soaking in 1n sodium carbonate solution, as well as changes in the ratio of potassium-sodium balance in plants. Thus at lower concentrations of sodium carbonate and 0.1 n sodium increasing of pigment content in barley is observed on the seventh day. The red laser light has a similar stimulating action: the chlorophyll content of barley plants increased after the red laser treatment of barley seeds. However, the chlorophyll contents were depressed when the seeds were exposed to far red light with wavelengths of 754±10 nm. Using these factors, one can manage the content of chlorophyll and sodium-potassium balance in the initial stages of barley ontogenesis in the technology of barley juice or the powder for a healthy and proper human diet.

  12. Carbon-supported cobalt catalyst for hydrogen generation from alkaline sodium borohydride solution

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongyan; Liu, Xinmin; Cao, Changqing; Guo, Qingjie [College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Dai, Ping [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China)

    2008-08-01

    Low cost transition metal catalysts with high performance are attractive for the development of on-board hydrogen generation systems by catalytic hydrolysis of sodium borohydride (NaBH{sub 4}) in fuel cell fields. In this study, hydrogen production from alkaline NaBH{sub 4} via hydrolysis process over carbon-supported cobalt catalysts was studied. The catalytic activity of the supported cobalt catalyst was found to be highly dependent on the calcination temperatures. The hydrogen generation rate increases with calcination temperatures in the range of 200-400 C, but a high calcination temperature above 500 C led to markedly decreased activity. X-ray diffraction patterns reveal that the catalysts experience phase transition from amorphous Co-B to crystalline cobalt hydroxide with increase in calcination temperatures. The reaction performance is also dependent on the concentration of NaBH{sub 4}, and the hydrogen generation rate increases for lower NaBH{sub 4} concentrations and decreases after reaching a maximum at 10 wt.% of NaBH{sub 4}. (author)

  13. Evaluation of cardiovascular toxicity of carbon nanotubes functionalized with sodium hyaluronate in oral regenerative medicine

    Energy Technology Data Exchange (ETDEWEB)

    Joviano-Santos, J.V.; Sá, M.A.; De Maria, M.L.A.; Almeida, T.C.S. [Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Geraldo, V.; Oliveira, S.; Ladeira, L.O. [Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Ferreira, A.J. [Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil)

    2014-05-23

    It has been demonstrated that carbon nanotubes (CNTs) associated with sodium hyaluronate (HY-CNTs) accelerate bone repair in the tooth sockets of rats. Before clinical application of HY-CNTs, it is important to assess their biocompatibility. Moreover, cardiac toxicity may be caused by the translocation of these particles to the blood stream. The aim of this study was to evaluate possible changes in cardiovascular function in male Wistar rats whose tooth sockets were treated with either CNTs or HY-CNTs (100 μg/mL, 0.1 mL). Blood pressure and heart rate were monitored in conscious rats 7 days after treatment. Cardiac function was evaluated using the Langendorff perfusion technique. The data showed no changes in blood pressure or heart rate in rats treated with either CNTs or HY-CNTs, and no significant changes in cardiac function were found in any of the groups. To confirm these findings, experiments were conducted in rats injected intraperitoneally with a high concentration of either CNTs or HY-CNTs (0.75 mg/kg). The same parameters were analyzed and similar results were observed. The results obtained 7 days following injection indicate that the administration of low concentrations of CNTs or HY-CNTs directly into tooth sockets did not cause any significant change in cardiovascular function in the rats. The present findings support the possibility of using these biocomposites in humans.

  14. Carbon nanotubes functionalized with sodium hyaluronate restore bone repair in diabetic rat sockets.

    Science.gov (United States)

    Sá, M A; Andrade, V B; Mendes, R M; Caliari, M V; Ladeira, L O; Silva, E E; Silva, G A B; Corrêa-Júnior, J D; Ferreira, A J

    2013-07-01

    We evaluated the effects of sodium hyaluronate (HY) and carbon nanotubes functionalized with HY (HY-CNT) on bone repair in the tooth sockets of diabetic rats. Diabetes was induced by streptozotocin (50 mg kg(-1) i.v.), and the sockets were divided into normal control, diabetic control, diabetic treated with HY (1%), and diabetic treated with HY-CNT (100 μg ml(-1)) groups. The sockets were analyzed according to the percentage of bone formation and the number of cell nuclei. The percentage of bone trabeculae was lower in diabetic control animals (11.16 ± 5.10% vs 41.92 ± 6.34% in normal animals) after 14 days. Treating diabetic animals with HY or HY-CNT significantly increased the percentage of neoformed trabeculae (HY: 29.43 ± 3.29%; HY-CNT: 36.90 ± 3.07%). Moreover, the sockets of diabetic animals had an increased number of cell nuclei and HY or HY-CNT reduced this parameter. Our results indicate that HY and HY-CNT restore bone repair in the tooth sockets of diabetic rats, suggesting that these biomaterials are potential adjuvant therapies for the management of diabetes. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Uranium recovery by leaching with sodium carbonate at high temperature and pressure

    International Nuclear Information System (INIS)

    Soerensen, E.; Koefoed, S.; Lundgaard, T.

    1990-09-01

    An alkaline rock from the Ilimaussaq instrusion, SW Greenland, was proposed as a source of uranium. Its principal uranium bearing mineral, Steenstrupine, is a complex sodium REE phosphosilicate in which Fe, Mn, Th and U are minor constituents. A special feature of this ore body is the content of water soluble minerals: NaF (Villiaumite), Na 2 Si 2 O 5 (Natrosilite) and an organic substance which displays the characteristics of humus. Sulfides are sparse, the most important one being ZnS (Sphalerite) of which the content is generally less than 0.5%. In the mineral under consideration (Lujavrite) the Steenstrupine is mainly finelay disseminated throughout the rock, yielding a uranium content of 300-400 ppm and thorium content of 800-1000 ppm. Laboratory tests indicated that high temperature carbonate leaching was necessary to decompose Steenstrupine. The optium temperature was shown to be 260 deg. C and the leach liquor composition 120 g/l of NaHCO 3 and 20 g/l of Na 2 C0 3 . Addition of oxygen is necessary. The process was developed to industrial scale in a continuous pipe autoclave with a retention time of 20 min. After filtering on a belt filter, the liquor was recycled several times to obtain a higher U-concentration. By reductive precipitation with iron powder a raw UO 2 was obtained. It was purified after dissolution in HNO 3 . An overall yield of 80% could be obtained. (author) 32 tabs., 13 ills., 24 refs

  16. Effects of sodium carbonate pretreatment on the chemical compositions and enzymatic saccharification of rice straw.

    Science.gov (United States)

    Yang, Linfeng; Cao, Jie; Jin, Yongcan; Chang, Hou-min; Jameel, Hasan; Phillips, Richard; Li, Zhongzheng

    2012-11-01

    The effects of sodium carbonate (Na(2)CO(3)) pretreatment on the chemical compositions and enzymatic saccharification of rice straw were investigated. The enzymatic digestibility of rice straw is enhanced after pretreatment since pretreated solids show significant delignification with high sugar availability. During pretreatment, an increasing temperature and Na(2)CO(3) charge leads to enhanced delignification, whereas an increased degradation of polysaccharides as well, of which xylan acts more susceptible than glucan. The sugar recovery of enzymatic hydrolysis goes up rapidly with the total titratable alkali (TTA) increasing from 0% to 8%, and then it reaches a plateau. The highest sugar recovery of rice straw after pretreatment, 71.7%, 73.2%, and 76.1% for total sugar, glucan, and xylan, respectively, is obtained at 140°C, TTA 8% and cellulase loading of 20 FPU/g-cellulose. In this condition, the corresponding delignification ratio of pretreated solid is 41.8%, while 95% of glucan and 76% of xylan are conserved. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Experimental and numerical analysis of sodium-carbonate salt gradient solar-pond performance under simulated solar-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Hueseyin; Ozkaymak, Mehmet [Zonguldak Karaelmas University, Technical Education Faculty, 78200 Karabuk (Turkey); Binark, A. Korhan [Marmara University, Technical Education Faculty, 34722 Kuyubasi-Istanbul (Turkey)

    2006-04-01

    The objective of this study is to investigate experimentally and theoretically whether sodium carbonate (Na{sub 2}CO{sub 3}) salt is suitable for establishing a salinity gradient in a salt-gradient solar-pond (SGSP). For this purpose, a small-scale prismatic solar-pond was constructed. Experiments were conducted in the laboratory under the incident radiation from two halogen-lamps acting as a solar simulator. Furthermore, a one-dimensional transient mathematical model that describes the heat and mass transfer behaviour of the SGSP was developed. The differential equations obtained were solved numerically using a finite-difference method. It was found from the experiments that the density gradient, achieved using sodium carbonate salt, can suppress convection from the bottom to the surface of the pond. (author)

  18. Comparison of sodium carbonate pretreatment for enzymatic hydrolysis of wheat straw stem and leaf to produce fermentable sugars.

    Science.gov (United States)

    Jin, Yongcan; Huang, Ting; Geng, Wenhui; Yang, Linfeng

    2013-06-01

    The specific characteristics of biomass structure and chemical composition of straw stem and leaf may result in different behavior of pretreatment and enzymatic hydrolysis. In this work, sodium carbonate (SC) was employed as a pretreatment to improve the enzymatic digestibility of wheat straw. The chemical composition and enzymatic hydrolysis of wheat straw stem and leaf (sheath included) were investigated comparatively. Most of the polysaccharides are kept in the solid fractions after SC pretreatment, while the stem has better delignification selectivity than leaf at high temperature. The enzymatic hydrolysis efficiency of wheat straw leaf is significantly higher than that of stem. The maximum total sugar yield from SC pretreated leaf was about 16% higher than stem. The results show that sodium carbonate is of great potential to be used as a pretreatment for the production of bioethanol from straw handling waste in a straw pulp mill with a low feedstock cost. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Experimental and numerical analysis of sodium-carbonate salt gradient solar-pond performance under simulated solar-radiation

    International Nuclear Information System (INIS)

    Kurt, Hueseyin; Ozkaymak, Mehmet; Binark, A. Korhan

    2006-01-01

    The objective of this study is to investigate experimentally and theoretically whether sodium carbonate (Na 2 CO 3 ) salt is suitable for establishing a salinity gradient in a salt-gradient solar-pond (SGSP). For this purpose, a small-scale prismatic solar-pond was constructed. Experiments were conducted in the laboratory under the incident radiation from two halogen-lamps acting as a solar simulator. Furthermore, a one-dimensional transient mathematical model that describes the heat and mass transfer behaviour of the SGSP was developed. The differential equations obtained were solved numerically using a finite-difference method. It was found from the experiments that the density gradient, achieved using sodium carbonate salt, can suppress convection from the bottom to the surface of the pond

  20. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model

    Science.gov (United States)

    Krissansen-Totton, Joshua; Arney, Giada N.; Catling, David C.

    2018-04-01

    The early Earth’s environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from 6.6‑0.4+0.6 (2σ) at 4.0 Ga to 7.0‑0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9‑0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering.

  1. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model.

    Science.gov (United States)

    Krissansen-Totton, Joshua; Arney, Giada N; Catling, David C

    2018-04-17

    The early Earth's environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0-50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from [Formula: see text] (2σ) at 4.0 Ga to [Formula: see text] (2σ) at the Archean-Proterozoic boundary, and to [Formula: see text] (2σ) at the Proterozoic-Phanerozoic boundary. This evolution is driven by the secular decline of pCO 2 , which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. Copyright © 2018 the Author(s). Published by PNAS.

  2. Reaction of Hydrogen Chloride Gas with Sodium Carbonate and Its Deep Removal in a Fixed-Bed Reactor

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Pohořelý, Michael; Šyc, Michal; Chen, Po-Ch.

    2014-01-01

    Roč. 53, č. 49 (2014), s. 19145-19158 ISSN 0888-5885 R&D Projects: GA ČR GC14-09692J Grant - others:NSC(TW) 102WBS0300011 Institutional support: RVO:67985858 Keywords : hot fuel gas purification * hydrogen chloride gas * active sodium carbonate Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.587, year: 2014

  3. Effect of Calcium Nitrate and Sodium Nitrite on the Rebar Corrosion of Medium Carbon Steel in Seawater and Cassava Fluid

    OpenAIRE

    Adamu, M; Umoru, LE; Ige, OO

    2014-01-01

    Inhibitors are regularly used as one of the principal prevention and control techniques in reinforcement corrosion. Hence this study investigates the effect of calcium nitrate and sodium nitrite inhibitors on the rebar corrosion of medium carbon steel in seawater and cassava fluid with a view to determining inhibitive potentials of the different inhibitors in the two media. Gravimetric and voltametric techniques were employed in this study and a total of forty-five corrosion coupons of differ...

  4. The use of sodium carbonate to improve curing treatments against green and blue moulds on citrus fruits.

    Science.gov (United States)

    Plaza, Pilar; Usall, Josep; Torres, Rosario; Abadias, Maribel; Smilanick, Joseph L; Viñas, Immaculada

    2004-08-01

    The effectiveness of curing oranges and lemons at 33 degrees C for 65h followed by storage under ambient and cold-storage conditions was investigated. This treatment effectively reduced the incidence of Penicillium digitatum (Pers) Sacc and P italicum Wehmer decay on inoculated and naturally infected oranges and lemons stored at 20 degrees C for 7 days. However, it failed to control green and blue mould infections on fruits placed in long-term cold storage, except green mould on oranges, which was effectively controlled. Dipping fruits in a sodium carbonate solution (20 g litre(-1)) for 2.5 min following a curing treatment at 33 degrees C for 65 h satisfactorily reduced green and blue mould incidence during subsequent long-term storage at 4 degrees C on oranges and at 10 degrees C on lemons. The efficacy was greater on injured fruits inoculated after the combination of treatments was applied, achieving a 60-80% reduction in decay in comparison with the curing treatment alone in all cases. A significant reduction of blue mould was also observed on fruits inoculated both before the treatments and on those re-inoculated after the treatments, demonstrating both protectant and eradicant activity. Thus, combining curing at 33 degrees C for 65 h with sodium carbonate treatment effectively controlled these post-harvest diseases on artificially inoculated citrus fruits and protected against re-infection. With naturally inoculated lemons, curing followed by sodium carbonate significantly reduced both green and blue mould incidence, but was not superior to curing alone. With naturally infected oranges, curing significantly reduced blue mould, but decay was not reduced further when followed by sodium carbonate treatment.

  5. Morphological alteration, lysosomal membrane fragility and apoptosis of the cells of Indian freshwater sponge exposed to washing soda (sodium carbonate).

    Science.gov (United States)

    Mukherjee, Soumalya; Ray, Mitali; Dutta, Manab Kumar; Acharya, Avanti; Mukhopadhyay, Sandip Kumar; Ray, Sajal

    2015-12-01

    Washing soda is chemically known as sodium carbonate and is a component of laundry detergent. Domestic effluent, drain water and various anthropogenic activities have been identified as major routes of sodium carbonate contamination of the freshwater ecosystem. The freshwater sponge, Eunapius carteri, bears ecological and evolutionary significance and is considered as a bioresource in aquatic ecosystems. The present study involves estimation of morphological damage, lysosomal membrane integrity, activity of phosphatases and apoptosis in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Exposure to washing soda resulted in severe morphological alterations and damages in cells of E. carteri. Fragility and destabilization of lysosomal membranes of E. carteri under the sublethal exposure was indicative to toxin induced physiological stress in sponge. Prolonged exposure to sodium carbonate resulted a reduction in the activity of acid and alkaline phosphatases in the cells of E. carteri. Experimental concentration of 8 mg/l of washing soda for 192 h yielded an increase in the physiological level of cellular apoptosis among the semigranulocytes and granulocytes of E. carteri, which was suggestive to possible shift in apoptosis mediated immunoprotection. The results were indicative of an undesirable shift in the immune status of sponge. Contamination of the freshwater aquifers by washing soda thus poses an alarming ecotoxicological threat to sponges. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Modelling with response surface methodology of the effects of egg yolk, egg white and sodium carbonate on some textural properties of beef patties.

    Science.gov (United States)

    Parlak, Ozgür; Zorba, Omer; Kurt, Sükrü

    2014-04-01

    This study was accomplished to determine the effects of egg yolk, egg white and sodium carbonate on textural properties of beef patties by using Central Composite Design of Response Surface Methodology. Meat patties were prepared using beef, lamb tail fat and spices. Effects of addition of egg yolk powder (0-1%), egg white powder (0-1%) and sodium carbonate (0-1%) on textural properties were studied by using a texture analyzer. The TPA and cutting force tests were measured in the samples. Effects of sodium carbonate were found to be significant (P  0.05). The levels of sodium carbonate up to 0.72% improved the textural properties of beef patties.

  7. A simple protocol for the routine calibration of pH meters

    Directory of Open Access Journals (Sweden)

    A. FEDERMAN NETO

    2009-01-01

    Full Text Available

    A simplified laboratory protocol for the calibration of pH meters is described and tested. It is based on the use of two analytical primary buffer solutions, potassium hydrogen phthalate and Borax (sodium tetraborate decahydrate of precisely known concentrations and pH. The solutions may be stored at room temperature for long periods, without decomposition and used directly. The calibration of the meter can be checked with standard solutions of sodium dihydrogen phosphate, sodium carbonate, sodium benzoate, sodium salicylate or potassium oxalate. Methods for the purification of Borax and potassium chloride are also given, and a new method for the neutralization of 0.9% saline is suggested. Keywords: pH meters (calibration; saline (0.9%; pH standards; potassium biphthalate; Borax.

  8. High cyclability of carbon-coated TiO2 nanoparticles as anode for sodium-ion batteries

    International Nuclear Information System (INIS)

    Ge, Yeqian; Jiang, Han; Zhu, Jiadeng; Lu, Yao; Chen, Chen; Hu, Yi; Qiu, Yiping; Zhang, Xiangwu

    2015-01-01

    Highlights: • Titanium oxide nanopaticles were modified by carbon coating from pyrolyzing of PVP. • Carbon coating gave rise to excellent cycling ability of TiO 2 for sodium-ion batteries. • The reversible capacity of carbon-coated TiO 2 reached 242.3 mAh g −1 at 30 mA g −1 . • Good rate performance of carbon-coated TiO 2 was presented up to 800 mA g −1 . - Abstract: Owing to the merits of good chemical stability, elemental abundance and nontoxicity, titanium dioxide (TiO 2 ) has drawn increasing attraction for use as anode material in sodium-ion batteries. Nanostructured TiO 2 was able to achieve high energy density. However, nanosized TiO 2 is typically electrochemical instable, which leads to poor cycling performance. In order to improve the cycling stability, carbon from thermolysis of poly(vinyl pyrrolidone) was coated onto TiO 2 nanoparticles. Electronic conductivity and electrochemical stability were enhanced by coating carbon onto TiO 2 nanoparticles. The resultant carbon-coated TiO 2 nanoparticles exhibited high reversible capacity (242.3 mAh g −1 ), high coulombic efficiency (97.8%), and good capacity retention (87.0%) at 30 mA g −1 over 100 cycles. By comparison, untreated TiO 2 nanoparticles showed comparable reversible capacity (237.3 mAh g −1 ) and coulombic efficiency (96.2%), but poor capacity retention (53.2%) under the same condition. The rate performance of carbon-coated TiO 2 nanoparticles was also displayed as high as 127.6 mAh g −1 at a current density of 800 mA g −1 . The improved cycling performance and rate capability were mostly attributed to protective carbon layer helping stablize solid electrolyte interface formation of TiO 2 nanoparticles and improving the electronic conductivity. Therefore, it is demonstrated that carbon-coated TiO 2 nanoparticles are promising anode candidate for sodium-ion batteries

  9. Long-term progress prediction for the carbon steel corrosion in diluted artificial seawater with and without zinc / sodium carbonate mixed phosphate

    International Nuclear Information System (INIS)

    Fujii, Kazumi; Ishioka, Shinichi; Iwanami, Masaru; Kaneko, Tetsuji; Tanaka, Norihiko; Kawaharada, Yoshiyuki; Yokoyama, Yutaka; Umehara, Ryuji; Kato, Chiaki; Ueno, Fumiyoshi; Fukaya, Yuichi; Kumaga, Katsuhiko

    2017-01-01

    The Fukushima Daiichi Nuclear Power Plants (1F) were damaged by an unprecedented severe accident in the great east Japan earthquake on 11th, March, 2011, and seawater and fresh water were injected as an emergency countermeasure for the core cooling. The primary containment vessels (PCVs), made of carbon steel, were exposed to seawater and fresh water, and have had the possibility of corrosion. The PCVs of 1F are the most important equipment for the core cooling and removal of the fuel debris, the structural integrity of the PCV must be maintained until decommissioning. Therefore, evaluation of PCV carbon steel corrosion behavior is important, as well as evaluation of corrosion inhibitors as one of the corrosion protection methods. In this study, long-term immersion corrosion tests for up to 10000 hours were performed in diluted artificial seawater simulating 1F with and without zinc / sodium carbonate mixed phosphate. Based on the long-term immersion corrosion test results, diagnosis method of the reduction in plate thickness of the nuclear vessel was examined. The validity of the existing corrosion progress models following parabolic rate law was confirmed. The corrosion progress models were also applicable to the corrosion inhibited condition adding zinc / sodium carbonate mixed phosphate. It was found that the corrosion rate of carbon steel drastically fell down by adding this corrosion inhibitor. (author)

  10. Comparison of sodium carbonate-oxygen and sodium hydroxide-oxygen pretreatments on the chemical composition and enzymatic saccharification of wheat straw.

    Science.gov (United States)

    Geng, Wenhui; Huang, Ting; Jin, Yongcan; Song, Junlong; Chang, Hou-Min; Jameel, Hasan

    2014-06-01

    Pretreatment of wheat straw with a combination of sodium carbonate (Na2CO3) or sodium hydroxide (NaOH) with oxygen (O2) 0.5MPa was evaluated for its delignification ability at relatively low temperature 110°C and for its effect on enzymatic hydrolysis efficiency. In the pretreatment, the increase of alkali charge (as Na2O) up to 12% for Na2CO3 and 6% for NaOH, respectively, resulted in enhancement of lignin removal, but did not significantly degrade cellulose and hemicellulose. When the pretreated solid was hydrolyzed with a mixture of cellulases and hemicellulases, the sugar yield increased rapidly with the lignin removal during the pretreatment. A total sugar yield based on dry matter of raw material, 63.8% for Na2CO3-O2 and 71.9% for NaOH-O2 was achieved under a cellulase loading of 20FPU/g-cellulose. The delignification efficiency and total sugar yield from enzymatic hydrolysis were comparable to the previously reported results at much higher temperature without oxygen. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Solution pH and oligoamine molecular weight dependence of the transition from monolayer to multilayer adsorption at the air-water interface from sodium dodecyl sulfate/oligoamine mixtures.

    Science.gov (United States)

    Halacheva, S S; Penfold, J; Thomas, R K; Webster, J R P

    2013-05-14

    Neutron reflectivity and surface tension have been used to investigate the solution pH and oligoamine molecular weight dependence of the adsorption of sodium dodecyl sulfate (SDS)/oligoamine mixtures at the air-water interface. For diethylenetriamine, triamine, or triethylenetetramine, tetramine mixed with SDS, there is monolayer adsorption at pH 7 and 10, and multilayer adsorption at pH 3. For the slightly higher molecular weight tetraethylenepentamine, pentamine, and pentaethylenehexamine, hexamine, the adsorption is in the form of a monolayer at pH 3 and multilayers at pH 7 and 10. Hence, there is a pH driven transition from monolayer to multilayer adsorption, which shifts from low pH to higher pH as the oligoamine molecular weight increases from tetramine to pentamine. This results from the relative balance between the electrostatic attraction between the SDS and amine nitrogen group which decreases as the charge density decreases with increasing pH, the ion-dipole interaction between the amine nitrogen and SDS sulfate group which is dominant at higher pH, and the hydrophobic interalkyl chain interaction between bound SDS molecules which changes with oligoamine molecular weight.

  12. Synthesis of sodium caseinate-calcium carbonate microspheres and their mineralization to bone-like apatite

    Science.gov (United States)

    Xu, Zhewu; Liang, Guobin; Jin, Lin; Wang, Zhenling; Xing, Chao; Jiange, Qing; Zhang, Zhiguang

    2014-06-01

    Phosphoproteins can induce and stabilize calcium carbonate (CaCO3) vaterite, which has desirable features for high reactivity. The purpose of this study was to synthesize bioactive CaCO3 microspheres for bone regeneration. Sodium caseinate (NaCas)-containing CaCO3 microspheres, with the crystal phase of vaterite, were synthesized by fast precipitation in an aqueous solution of CaCl2, Na2CO3, and 2 mg/mL of NaCas. The uniform microspheres exhibited rougher surfaces and lower negative charges than CaCO3 particles without NaCas addition. Fourier-transform infrared spectroscopy (FT-IR) of the microspheres showed characteristic peaks or bands corresponding to phosphate and hydroxyl groups. Thermogravimetric analysis (TGA) curves exhibited approximately 5% weight loss below 600 °C due to the decomposition of NaCas. Scanning electron microscope (SEM) images showed lath-like hydroxyapatite (HAp) on the surface after soaking in simulated body fluid (SBF) at 37 °C for 5 and 10 days. Energy dispersive X-ray spectrometry (EDS) revealed that the agglomerates were composed of Ca, C, O, P, Na, and Mg elements, and the Ca/P ratios ranged from 1.53 to 1.56. X-ray diffraction (XRD) patterns exhibited peaks characteristic of hydroxyapatite. The results of this study demonstrated that the addition of NaCas induced the formation of vaterite microspheres which possesses an enhanced apatite formation after soaking in SBF at 37 °C for 5 and 10 days. These NaCas-CaCO3 microspheres may be a potential biomaterial for bone regeneration.

  13. Effect of sodium carbonate solution on self-setting properties of tricalcium silicate bone cement.

    Science.gov (United States)

    Zhiguang Huan; Jiang Chang

    2008-11-01

    In this study, the effects of sodium carbonate (Na(2)CO(3) ) solution with different concentrations (10, 15, 20, and 25 wt%) as liquid phase on the setting time and compressive strength of tricalcium silicate bone cements are investigated. The in vitro bioactivity and degradability of the resultant Ca(3)SiO(5)-Na(2)CO(3) solution paste was also studied. The results indicate that as the concentration of Na(2)CO(3) solution varies from 0 to 25 wt%, the initial and final setting time of the cement decrease significantly from 90 to 20 min and from 180 to 45 min, respectively. After setting for 24 h, the compressive strength of Ca(3)SiO(5)-Na(2)CO(3) solution paste reaches 5.1 MPa, which is significantly higher than that of Ca( 3)SiO(5)-water cement system. The in vitro bioactivity of the cements is investigated by soaking in simulated body fluid (SBF) for 7 days. The results show that the Ca(3)SiO(5)-Na(2)CO( 3) solution bone cement has a good bioactivity and can degrade in Ringer's solution. The results indicate that Na(2)CO(3) solution as a liquid phase significantly improves the self-setting properties of Ca( 3)SiO(5) cement as compared to water. The Ca(3)SiO( 5) cement paste prepared using Na(2)CO(3) solution shows good bioactivity and moderate degradability, and the Ca(3)SiO( 5)-Na(2)CO(3) solution system may be used as degradable and bioactive bone defect filling materials.

  14. MoS{sub 2}/cotton-derived carbon fibers with enhanced cyclic performance for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang [School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, 510641 (China); Yang, Yan [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); Liu, Jiangwen; Ouyang, Liuzhang; Liu, Jun; Hu, Renzong [School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, 510641 (China); Yang, Lichun, E-mail: mslcyang@scut.edu.cn [School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, 510641 (China); Zhu, Min [School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, 510641 (China)

    2017-08-15

    Highlights: • MoS{sub 2} nanosheets vertically grow on cotton-derived carbon microfibers. • The carbon fibers facilitate charge transfer and structure stabilization. • The MoS{sub 2}/CDCFs exhibit enhanced cyclic performance for reversible Na{sup +} storage. - Abstract: Carbon fibers derived from bio-template are low cost and environmental benign, therefore have attracted much attention in energy storage materials. In this work, we successfully fabricated MoS{sub 2}/cotton-derived carbon fibers (MoS{sub 2}/CDCFs) via hydrothermal route followed by carbonization process. In the composite of MoS{sub 2}/CDCFs, MoS{sub 2} nanosheets vertically grow on the carbon fibers which offer fast ways for electron transfer and at the same time act as robust support to buffer the volume changes of MoS{sub 2} nanosheets during discharge/charge cycles. As anode materials for sodium-ion batteries, MoS{sub 2}/CDCFs exhibit good rate performance and markedly enhanced cyclic stability due to the conductive support of CDCFs. At a current density of 0.1 A g{sup −1}, the MoS{sub 2}/CDCFs-1 shows an initial reversible capacity of 504.9 mAh g{sup −1}, and maintains 444.5 mAh g{sup −1} after 50 cycles. Even when the current density increases to 0.5 A g{sup −1}, it maintains 323.1 mAh g{sup −1} after 150 cycles, which is much higher than the capacity retention of 149.6 mAh g{sup −1} for the bare MoS{sub 2} nanosheets. The improved electrochemical performance verifies the effective strategy of using cotton as carbon source to construct hierarchical composites for sodium-ion batteries.

  15. The Dissolution of Synthetic Na-Boltwoodite in Sodium Carbonate Solutions

    International Nuclear Information System (INIS)

    Ilton, Eugene S.; Liu, Chongxuan; Yantasee, Wassana; Wang, Zheming; Moore, Dean A.; Felmy, Andrew R.; Zachara, John M.

    2006-01-01

    Uranyl silicates such as uranophane and Na-boltwoodite appear to control the solubility of uranium in the contaminated sediments at the US Department of Energy Hanford site (Liu et al., 2004). Consequently, the solubility of synthetic Na-boltwoodite was determined over a wide range of bicarbonate concentrations, from circumneutral to alkaline pH, that are representative of porewater and groundwater compositions at the Hanford site. Results show that Na-boltwoodite dissolution was nearly congruent and its solubility increased with increasing bicarbonate concentration. Calculated solubility constants varied by nearly 2 log units from low bicarbonate (no added NaCO3) to 50 mmol/L bicarbonate. However, the solubility constants only vary by 0.5 log units from 0 added bicarbonate to 1.2 mmol/L bicarbonate, where logKsp = 5.39-5.92 and the average logKsp = 5.63. No systematic trend in logKsp was apparent over this range in bicarbonate concentrations. LogKsp values trended down with increasing bicarbonate concentration, where logKsp = 4.06 at 50 mmol/L bicarbonate. We conclude that the calculated solubility constants at high bicarbonate are compromised by an incomplete or inaccurate uranyl-carbonate speciation model

  16. Carbon Quantum Dot Surface-Engineered VO2 Interwoven Nanowires: A Flexible Cathode Material for Lithium and Sodium Ion Batteries.

    Science.gov (United States)

    Balogun, Muhammad-Sadeeq; Luo, Yang; Lyu, Feiyi; Wang, Fuxin; Yang, Hao; Li, Haibo; Liang, Chaolun; Huang, Miao; Huang, Yongchao; Tong, Yexiang

    2016-04-20

    The use of electrode materials in their powdery form requires binders and conductive additives for the fabrication of the cells, which leads to unsatisfactory energy storage performance. Recently, a new strategy to design flexible, binder-, and additive-free three-dimensional electrodes with nanoscale surface engineering has been exploited in boosting the storage performance of electrode materials. In this paper, we design a new type of free-standing carbon quantum dot coated VO2 interwoven nanowires through a simple fabrication process and demonstrate its potential to be used as cathode material for lithium and sodium ion batteries. The versatile carbon quantum dots that are vastly flexible for surface engineering serve the function of protecting the nanowire surface and play an important role in the diffusion of electrons. Also, the three-dimensional carbon cloth coated with VO2 interwoven nanowires assisted in the diffusion of ions through the inner and the outer surface. With this unique architecture, the carbon quantum dot nanosurface engineered VO2 electrode exhibited capacities of 420 and 328 mAh g(-1) at current density rate of 0.3 C for lithium and sodium storage, respectively. This work serves as a milestone for the potential replacement of lithium ion batteries and next generation postbatteries.

  17. Novel pH- and temperature-responsive blend hydrogel microspheres of sodium alginate and PNIPAAm-g-GG for controlled release of isoniazid.

    Science.gov (United States)

    Kajjari, Praveen B; Manjeshwar, Lata S; Aminabhavi, Tejraj M

    2012-12-01

    This paper reports the preparation and characterization of novel pH- and thermo-responsive blend hydrogel microspheres of sodium alginate (NaAlg) and poly(N-isopropylacrylamide)(PNIPAAm)-grafted-guar gum (GG) i.e., PNIPAAm-g-GG by emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. Isoniazid (INZ) was chosen as the model antituberculosis drug to achieve encapsulation up to 62%. INZ has a plasma half-life of 1.5 h, whose release was extended up to 12 h. Fourier transform infrared spectroscopy was used to confirm the grafting reaction and chemical stability of INZ during the encapsulation. Differential scanning calorimetry was used to investigate the drug's physical state, while powder X-ray diffraction confirmed the molecular level dispersion of INZ in the matrix. Scanning electron microscopy confirmed varying surface morphologies of the drug-loaded microspheres. Temperature- and pH-responsive nature of the blend hydrogel microspheres were investigated by equilibrium swelling, and in vitro release experiments were performed in pH 1.2 and pH 7.4 buffer media at 37°C as well as at 25°C. Kinetics of INZ release was analyzed by Ritger-Peppas empirical equation to compute the diffusional exponent parameter (n), whose value ranged between 0.27 and 0.58, indicating the release of INZ follows a diffusion swelling controlled release mechanism.

  18. Nitrifying aerobic granular sludge fermentation for releases of carbon source and phosphorus: The role of fermentation pH.

    Science.gov (United States)

    Zou, Jinte; Pan, Jiyang; He, Hangtian; Wu, Shuyun; Xiao, Naidong; Ni, Yongjiong; Li, Jun

    2018-07-01

    The effect of fermentation pH (uncontrolled, 4 and 10) on the releases of carbon source and phosphorus from nitrifying aerobic granular sludge (N-AGS) was investigated. Meanwhile, metal ion concentration and microbial community characterization were explored during N-AGS fermentation. The results indicated that N-AGS fermentation at pH 10 significantly promoted the releases of soluble chemical oxygen demand (SCOD) and total volatile fatty acids (TVFAs). However, SCOD and TVFA released from N-AGS were inhibited at pH 4. Moreover, acidic condition promoted phosphorus release (mainly apatite) from N-AGS during anaerobic fermentation. Nevertheless, alkaline condition failed to increase phosphorus concentration due to the formation of chemical-phosphate precipitates. Compared with the previously reported flocculent sludge fermentation, N-AGS fermentation released more SCOD and TVFAs, possibly due to the greater extracellular polymeric substances content and some hydrolytic-acidogenic bacteria in N-AGS. Therefore, N-AGS alkaline fermentation facilitated the carbon source recovery, while N-AGS acidic fermentation benefited the phosphorus recovery. Copyright © 2018. Published by Elsevier Ltd.

  19. Preparation of Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) Material and its Application to Electrochemical Degradation of Methylene Blue in Sodium Chloride Solution

    Science.gov (United States)

    Riyanto; Prawidha, A. D.

    2018-01-01

    Electrochemical degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode in sodium chloride have been done. The aim of this work was to degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC). Carbon chitosan composite electrode was preparing by Carbon and Chitosan powder and PVC in 4 mL tetrahydrofuran (THF) solvent and swirled flatly to homogeneous followed by drying in an oven at 100 °C for 3 h. The mixture was placed in stainless steel mould and pressed at 10 ton/cm2. Sodium chloride was used electrolyte solution. The effects of the current and electrolysis time were investigated using spectrophotometer UV-Visible. The experimental results showed that the carbon-chitosan composite electrode have higher effect in the electrochemical degradation of methylene blue in sodium chloride. Based on UV-visible spectra analysis shows current and electrolysis time has high effect to degradation of methylene blue in sodium chloride. Chitosan and polyvinyl chloride can strengthen the bond between the carbons so that the material has the high stability and conductivity. As conclusions is Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode have a high electrochemical activity for degradation of methylene blue in sodium chloride.

  20. Three-Dimensional SnS Decorated Carbon Nano-Networks as Anode Materials for Lithium and Sodium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Yanli Zhou

    2018-02-01

    Full Text Available The three-dimensional (3D SnS decorated carbon nano-networks (SnS@C were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g−1 for SnS@C composites can be obtained at 100 mA·g−1 after 100 cycles. Even cycled at a high current density of 2 A·g−1, the reversible capacity of this composite can be maintained at 610 mAh·g−1 after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g−1, and it retains a reversible capacity of 186 mAh·g−1 at 100 mA·g−1 after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles.

  1. Fractional ablative carbon dioxide laser followed by topical sodium stibogluconate application: A treatment option for pediatric cutaneous leishmaniasis.

    Science.gov (United States)

    Hilerowicz, Yuval; Koren, Amir; Mashiah, Jacob; Katz, Oren; Sprecher, Eli; Artzi, Ofir

    2018-05-01

    Leishmaniasis is a protozoan zoonotic parasitic infection with cutaneous, mucocutaneous, and visceral manifestations. Israel is endemic for cutaneous leishmaniasis, which is a self-limited disease but is associated with scarring, which is often a source of psychological and social burden for patients. Scars can be especially devastating for children and teenagers. A wide range of physical and medical approaches is used to treat cutaneous leishmaniasis, among which intralesional injections of sodium stibogluconate rank among the most frequently used. Unfortunately, despite being effective, this therapeutic modality can be very painful. Fractional ablative laser creates a controlled mesh-like pattern of tissue ablation in the skin that promotes dermal remodeling and collagen production while at the same time facilitating enhanced delivery of topically applied medications. Patients were treated with fractional ablative carbon dioxide laser followed by immediate topical application of sodium stibogluconate. All children were diagnosed with cutaneous leishmaniasis prior to treatment initiation.. Ten children were treated. One leishmania tropica-positive girl failed to respond. The other nine patients achieved clinical cure and demonstrated good to excellent final cosmesis. Self-rated patient satisfaction and tolerance were high No adverse effects were observed or reported during treatment. Fractional ablative carbon dioxide laser followed by topical sodium stibogluconate application appears to be a safe and promising treatment for cutaneous leishmaniasis infection in children. Future controlled studies are required to validate these findings and compare this technique with traditional approaches. © 2018 Wiley Periodicals, Inc.

  2. Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength

    KAUST Repository

    Lee, Jieun; Jeong, Sanghyun; Ye, Yun; Chen, Vicki; Vigneswaran, Saravanamuthu; Leiknes, TorOve; Liu, Zongwen

    2016-01-01

    The protein fouling behavior was investigated in the filtration of the multiwall carbon nanotube (MWCNT) composite membrane and commercial polyethersulfone ultrafiltration (PES-UF) membrane. The effect of solution chemistry such as pH and ionic strength on the protein fouling mechanism was systematically examined using filtration model such as complete pore blocking, intermediate pore blocking and cake layer formation. The results showed that the initial permeate flux pattern and fouling behavior of the MWCNT composite membrane were significantly influenced by pH and ionic strength while the effect of PES-UF membrane on flux was minimal. In a lysozyme (Lys) filtration, the severe pore blocking in the MWCNT membrane was made by the combined effect of intra-foulant interaction (Lys-Lys) and electrostatic repulsion between the membrane surface and the foulant at pH 4.7 and 10.4, and increasing ionic strength where the foulant-foulant interaction and membrane-fouling interaction were weak. In a bovine serum albumin (BSA) filtration, severe pore blocking was reduced by less deposition via the electrostatic interaction between the membrane and foulant at pH 4.7 and 10.4 and increasing ionic strength, at which the interaction between the membrane and BSA became weak. For binary mixture filtration, the protein fouling mechanism was more dominantly affected by foulant-foulant interaction (Lys-BSA, Lys-Lys, and BSA-BSA) at pH 7.0 and increase in ionic strength. This research demonstrates that MWCNT membrane fouling can be alleviated by changing pH condition and ionic strength based on the foulant-foulant interaction and the electrostatic interaction between the membrane and foulant.

  3. Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength

    KAUST Repository

    Lee, Jieun

    2016-11-04

    The protein fouling behavior was investigated in the filtration of the multiwall carbon nanotube (MWCNT) composite membrane and commercial polyethersulfone ultrafiltration (PES-UF) membrane. The effect of solution chemistry such as pH and ionic strength on the protein fouling mechanism was systematically examined using filtration model such as complete pore blocking, intermediate pore blocking and cake layer formation. The results showed that the initial permeate flux pattern and fouling behavior of the MWCNT composite membrane were significantly influenced by pH and ionic strength while the effect of PES-UF membrane on flux was minimal. In a lysozyme (Lys) filtration, the severe pore blocking in the MWCNT membrane was made by the combined effect of intra-foulant interaction (Lys-Lys) and electrostatic repulsion between the membrane surface and the foulant at pH 4.7 and 10.4, and increasing ionic strength where the foulant-foulant interaction and membrane-fouling interaction were weak. In a bovine serum albumin (BSA) filtration, severe pore blocking was reduced by less deposition via the electrostatic interaction between the membrane and foulant at pH 4.7 and 10.4 and increasing ionic strength, at which the interaction between the membrane and BSA became weak. For binary mixture filtration, the protein fouling mechanism was more dominantly affected by foulant-foulant interaction (Lys-BSA, Lys-Lys, and BSA-BSA) at pH 7.0 and increase in ionic strength. This research demonstrates that MWCNT membrane fouling can be alleviated by changing pH condition and ionic strength based on the foulant-foulant interaction and the electrostatic interaction between the membrane and foulant.

  4. Decreasing pH trend estimated from 25-yr time series of carbonate parameters in the western North Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Midorikawa, Takashi; Ishii, Masao; Sasano, Daisuke; Kosugi, Naohiro (Geochemical Research Dept., Meteorological Research Institute Tsukuba (Japan)), e-mail: midorika@mri-jma.go.jp; Saito, Shu (Geochemical Research Dept., Meteorological Research Institute, Tsukuba (Japan); Institute of Observational Research for Global Change (IORGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka (Japan)); Motoi, Tatsuo (Oceanographic Research Dept., Meteorological Research Institute, Tsukuba (Japan)); Kamiya, Hitomi; Nakadate, Akira; Nemoto, Kazuhiro (Global Environment and Marine Dept., Japan Meteorological Agency, Tokyo (Japan)); Inoue, Hisayuki Y. (Graduate School of Environmental Earth Science, Hokkaido Univ., Sapporo (Japan))

    2010-11-15

    We estimated long-term trends of ocean acidification in surface waters in latitudinal zones from 3 deg N to 33 deg N along the repeat hydrographic line at 137 deg E in the western North Pacific Ocean. Estimates were based on the observational records of oceanic CO{sub 2} partial pressure and related surface properties over the last two decades. The computed pH time series both for 25 yr in winter (late January to early February) and for 21 yr in summer (June-July) exhibited significant decreasing trends in the extensive subtropical to equatorial zones, with interannual variations that were larger in summer. The calculated rates of pH decrease ranged from 0.0015 to 0.0021 yr-1 (average, 0.0018 +- 0.0002 yr-1) in winter and from 0.0008 to 0.0019 yr-1 (average, 0.0013 +- 0.0005 yr-1 ) in summer. The thermodynamic effects of rising sea surface temperature (SST) accounted for up to 44% (average, 15%) of the trend of pH decrease in the subtropical region in winter, whereas a trend of decreasing SST slowed the pH decrease in the northern subtropical region (around 25 deg N) in summer. We used the results from recent trends to evaluate future possible thermodynamic changes in the upper ocean carbonate system

  5. The Sensitivity Of Carbon Steels' Susceptibility To Localized Corrosion To The pH Of Nitrate Based Nuclear Wastes

    International Nuclear Information System (INIS)

    Boomer, K.D.

    2010-01-01

    The Hanford tank reservation contains approximately 50 million gallons of liquid legacy radioactive waste from cold war weapons production, which is stored in 177 underground storage tanks. The tanks will be in use until waste processing operations are completed. The wastes tend to be high pH (over 10) and nitrate based. Under these alkaline conditions carbon steels tend to be passive and undergo relatively slow uniform corrosion. However, the presence of nitrate and other aggressive species, can lead to pitting and stress corrosion cracking. This work is a continuation of previous work that investigated the propensity of steels to suffer pitting and stress corrosion cracking in various waste simulants. The focus of this work is an investigation of the sensitivity of the steels' pitting and stress corrosion cracking susceptibility tosimulant pH. Previous work demonstrated that wastes that are high in aggressive nitrate and low in inhibitory nitrite are susceptible to localized corrosion. However, the previous work involved wastes with pH 12 or higher. The current work involves wastes with lower pH of 10 or 11. It is expected that at these lower pHs that a higher nitrite-to-nitrate ratio will be necessary to ensure tank integrity. This experimental work involved both electrochemical testing, and slow strain rate testing at either the free corrosion potential or under anodic polarization. The results of the current work will be discussed, and compared to work previously presented.

  6. Removal of Uranium and Associated Contaminants from Aqueous Solutions Using Functional Carbon Nanotubes-Sodium Alginate Conjugates

    Directory of Open Access Journals (Sweden)

    Hussein Allaboun

    2016-02-01

    Full Text Available Synthesis of hydrophilic/hydrophobic beads from functional carbon nanotubes (CNTs conjugated with sodium alginate was investigated. Glutaraldehyde was used as a coupling agent and Ca2+ as a crosslinking agent. The formed conjugate comprises two-dimensional sheets of sodium alginate bounded to long tufts of functional CNT tails of micro-size geometry. Detailed characterization of the conjugates was performed using thermogravimetric analysis (TGA and its first derivative (DTG, Fourier transform infrared (FTIR, and scanning electron microscope (SEM techniques. Different ratios of the conjugate were successfully prepared and used as biodegradable environmentally friendly sorbents. Removal of U6+, V3+, Cr3+, Mo3+, Pb2+, Mn2+, Cu2+, Ti4+ and Ni2+ from aqueous solutions using the synthesized biosorbent was experimentally demonstrated. Maximum metal uptake of 53 mg/g was achieved using the % Functional CNTs = 33 sample.

  7. Study of lithium extraction from brine water, Bledug Kuwu, Indonesia by the precipitation series of oxalic acid and carbonate sodium

    Science.gov (United States)

    Sulistiyono, Eko; Lalasari, Latifa Hanum; Mayangsari, W.; Prasetyo, A. B.

    2018-05-01

    Lithium is one of the key elements in the development of batteries for electric car applications. Currently, the resources of the world's lithium are derived from brine water and lithium mineral based on spodumene rock. Indonesia which is located in the area of the ring of fire, has potential brine water resources in some area, such as brine water from Bledug Kuwu, Central Java that used in this research. The purposes of this research are to characterize brine water, Bledug Kuwu and to investigate the influence of chemical solvents on Li, Na, K, Ca, Mg, Al, B ion precipitation from brine water. This research was done with 2 times the process of chemical precipitation that runs series as follows: 5 liters of brine water were chemically precipitated using 400 ml of 12.43 N oxalic acid and followed by chemical precipitation using 400 mL of 7.07 N sodium carbonate solutions. Evaporation and filtration processes were also done twice in an effort to separate white precipitate and filtrate. The filtrate was analyzed by ICP-OES and white precipitates (salts) were analyzed by SEM, XRD, and XRF. The result shows that oxalate precipitation process extracted 32.24% Al, 23.42% B, 22.43% Ca, 14.26% Fe, 3.21 % K, 9.86% Na and 14.26% Li, the following process by carbonate precipitation process extracted 98.86% Mg, 73% Ca, 22.53% Li, 82.04% Al, 14.38% B, 12.50% K, 2.27% Na. There is 63.21% lithium is not extracted from the series process. The SEM analysis shows that the structure of granules on the precipitated salts by oxalic acid form gentle cubic-shaped solid. In the other hand, oxalate precipitation followed by sodium carbonate has various particle sizes and the shape of crystals is fragments, prism and cube look like magnesium carbonate, calcium chloride, and calcite's crystal respectively. This is in accordance with XRD analysis that phases of whewellite (CaC2O4.H2O), disodium oxalate (Na2C2O4), magnesite (MgCO3), calcium lithium aluminum (Al1.19 Ca1Li0.81), dolomite (CaCO3

  8. In vivo measurement of intracellular pH in human brain during different tensions of carbon dioxide in arterial blood. A 31P-NMR study

    DEFF Research Database (Denmark)

    Jensen, K E; Thomsen, C; Henriksen, O

    1988-01-01

    The effect of changes in carbon dioxide tension in arterial blood upon intracellular pH in brain tissue was studied in seven healthy volunteers, aged 22-45 years. The pH changes were monitored by use of 31P nuclear magnetic resonance spectroscopy, performed on a whole-body 1.5 Tesla Siemens imaging...

  9. REDUCTION OF PLUTONIUM TO Pu$sup +3$ BY SODIUM DITHIONITE IN POTASSIUM CARBONATE

    Science.gov (United States)

    Miller, D.R.; Hoekstra, H.R.

    1958-12-16

    Plutonium values are reduced in an alkaline aqueous medlum to the trlvalent state by means of sodium dlthionite. Plutonlum values are also separated from normally assoclated contaminants by metathesizing a lanthanum fluoride carrier precipitate containing plutonium with a hydroxide solution, performing the metathesis in the presence of about 0.2 M sodium dithionite at a temperature of between 40 and 90 icient laborato C.

  10. Mutant carbonic anhydrase 4 impairs pH regulation and causes retinal photoreceptor degeneration.

    NARCIS (Netherlands)

    Yang, Z.; Alvarez, B.V.; Chakarova, C.; Jiang, L.; Karan, G.; Frederick, J.M.; Zhao, Y.; Sauve, Y.; Li, X.; Zrenner, E.; Wissinger, B.; Hollander, A.I. den; Katz, B.; Baehr, W.; Cremers, F.P.M.; Casey, J.R.; Bhattacharya, S.S.; Zhang, K.

    2005-01-01

    Retina and retinal pigment epithelium (RPE) belong to the metabolically most active tissues in the human body. Efficient removal of acid load from retina and RPE is a critical function mediated by the choriocapillaris. However, the mechanism by which pH homeostasis is maintained is largely unknown.

  11. Inhibitive effect of N,N'-Dimethylaminoethanol on carbon steel corrosion in neutral sodium chloride solution, at different temperatures

    Directory of Open Access Journals (Sweden)

    Hassoune Mohammed

    2018-01-01

    Full Text Available The inhibition of carbon steel corrosion in neutral sodium chloride solution by N,N'- Dimethylaminoethanol (DMEA, at different temperatures, was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS techniques. The results obtained confirm that DMEA is a good organic corrosion inhibitor for carbon steel in 0.5M of NaCl (concentration encountered in the Mediterranean seawater, over the whole range of temperatures studied. The inhibition efficiency (IE% increases with increasing DMEA concentration; it reaches highest value for a concentration around 0.125 mol.L-1. Potentiodynamic polarization data show that, the compound studied in this research predominantly act as anodic-type inhibitor. The EIS study reveals that the addition of DMEA decreases the corrosion rate of carbon steel in neutral sodium chloride solution, due to the fact that the inhibitor molecules are strongly adsorbed on the active sites following Langmuir isotherm, thus leading to the formation of a stable protective film on the steel surface which is able to keep the metal/solution interface in a passive state. Furthermore, the values of the activation parameters, i.e. ΔHa and Ea obtained in this study indicate that the adsorption process of DMEA is endothermic and could be mainly attributed to chemisorption, respectively.

  12. Rational design of Sn/SnO{sub 2}/porous carbon nanocomposites as anode materials for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaojia [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Xifei, E-mail: xfli2011@hotmail.com [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Center for Advanced Energy Materials and Devices, Xi’an University of Technology, Xi’an 710048 (China); Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071 (China); Fan, Linlin; Yu, Zhuxin; Yan, Bo; Xiong, Dongbin; Song, Xiaosheng; Li, Shiyu [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Adair, Keegan R. [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Li, Dejun, E-mail: dejunli@mail.tjnu.edu.cn [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Sun, Xueliang, E-mail: xsun9@uwo.ca [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China)

    2017-08-01

    Highlights: • Sn/SnO{sub 2}/porous carbon nanocomposites are rationally designed via a facile strategy. • The porous carbon mitigates the volume change and poor conductivity of Sn/SnO{sub 2}. • The nanocomposites exhibit the enhanced sodium storage performance. - Abstract: Sodium-ion batteries (SIBs) have successfully attracted considerable attention for application in energy storage, and have been proposed as an alternative to lithium ion batteries (LIBs) due to the abundance of sodium resources and low price. Sn has been deemed as a promising anode material in SIBs which holds high theoretical specific capacity of 845 mAh g{sup −1}. In this work we design nanocomposite materials consisting of porous carbon (PC) with SnO{sub 2} and Sn (Sn/SnO{sub 2}/PC) via a facile reflux method. Served as an anode material for SIBs, the Sn/SnO{sub 2}/PC nanocomposite delivers the primary discharge and charge capacities of 1148.1 and 303.0 mAh g{sup −1}, respectively. Meanwhile, it can preserve the discharge capacity approximately of 265.4 mAh g{sup −1} after 50 cycles, which is much higher than those of SnO{sub 2}/PC (138.5 mAh g{sup −1}) and PC (92.2 mAh g{sup −1}). Furthermore, the Sn/SnO{sub 2}/PC nanocomposite possesses better cycling stability with 77.8% capacity retention compared to that of SnO{sub 2}/PC (61.88%) over 50 cycles. Obviously, the Sn/SnO{sub 2}/PC composite with excellent electrochemical performance shows the great possibility of application in SIBs.

  13. Thermal stability and oxidizing properties of mixed alkaline earth-alkali molten carbonates: A focus on the lithium-sodium carbonate eutectic system with magnesium additions

    International Nuclear Information System (INIS)

    Frangini, Stefano; Scaccia, Silvera

    2013-01-01

    Highlights: • TG/DSC analysis was conducted on magnesium-containing eutectic Li/Na eutectic carbonates. • Magnesium influence on the oxygen solubility properties of carbonate was also experimentally determined at 600 °C and 650 °C. • A reproducible partial decarbonation process in premelting region caused formation of magnesium oxycarbonate-like phases. • The acidobase buffering action of magnesium oxycarbonate species could explain the high basic/oxidizing properties of such carbonate melts. • A general correlation between thermal instability in premelting region and basic/oxidizing melt properties was established. - Abstract: A comparative study on thermal behavior and oxygen solubility properties of eutectic 52/48 lithium/sodium carbonate salt containing minor additions of magnesium up to 10 mol% has been made in order to determine whether a general correlation between these two properties can be found or not. Consecutive TG/DSC heating/cooling thermal cycles carried out under alternating CO 2 and N 2 gas flows allowed to assign thermal events observed in the premelting region to a partial decarbonation process of the magnesium-alkali mixed carbonates. The observed decarbonation process at 460 °C is believed to come from initial stage of thermal decomposition of magnesium carbonate resulting in the metastable formation of magnesium oxycarbonate-like phases MgO·2MgCO 3 , in a similar manner as previously reported for lanthanum. Reversible formation and decomposition of the magnesium carbonate phase has been observed under a CO 2 gas atmosphere. The intensity of the decomposition process shows a maximum for a 3 mol% MgO addition that gives also the highest oxygen solubility, suggesting therefore that instability thermal analysis in the premelting region can be considered as providing an effective measure of the basicity/oxidizing properties of alkali carbonate melts with magnesium or, in more general terms, with cations that are strong modifiers of

  14. Lithium and sodium ion capacitors with high energy and power densities based on carbons from recycled olive pits

    Science.gov (United States)

    Ajuria, Jon; Redondo, Edurne; Arnaiz, Maria; Mysyk, Roman; Rojo, Teófilo; Goikolea, Eider

    2017-08-01

    In this work, we are presenting both lithium and sodium ion capacitors (LIC and NIC) entirely based on electrodes designed from recycled olive pit bio-waste derived carbon materials. On the one hand, olive pits were pyrolized to obtain a low specific surface area semigraphitic hard carbon to be used as the ion intercalation (battery-type) negative electrode. On the other hand, the same hard carbon was chemically activated with KOH to obtain a high specific surface area activated carbon that was further used as the ion-adsorption (capacitor-type) positive electrode. Both electrodes were custom-made to be assembled in a hybrid cell to either build a LIC or NIC in the corresponding Li- and Na-based electrolytes. For comparison purposes, a symmetric EDLC supercapacitor cell using the same activated carbon in 1.5 M Et4NBF4/acetonitrile electrolyte was also built. Both LIC and NIC systems demonstrate remarkable energy and power density enhancement over its EDLC counterpart while showing good cycle life. This breakthrough offers the possibility to easily fabricate versatile hybrid ion capacitors, covering a wide variety of applications where different requirements are demanded.

  15. Effect of ordered mesoporous carbon contact layer on the sensing performance of sputtered RuO2 thin film pH sensor.

    Science.gov (United States)

    Lonsdale, W; Maurya, D K; Wajrak, M; Alameh, K

    2017-03-01

    The effect of contact layer on the pH sensing performance of a sputtered RuO 2 thin film pH sensor is investigated. The response of pH sensors employing RuO 2 thin film electrodes on screen-printed Pt, carbon and ordered mesoporous carbon (OMC) contact layers are measured over a pH range from 4 to 10. Working electrodes with OMC contact layer are found to have Nernstian pH sensitivity (-58.4mV/pH), low short-term drift rate (5.0mV/h), low hysteresis values (1.13mV) and fast reaction times (30s), after only 1h of conditioning. A pH sensor constructed with OMC carbon contact layer displays improved sensing performance compared to Pt and carbon-based counterparts, making this electrode more attractive for applications requiring highly-accurate pH sensing with reduced conditioning time. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Use of sodium carbonate as a binder in ceramic tile compositions; Uso del carbonato sodico como ligante en composiciones de baldosas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Quereda, F.; Sanchez, E.; Garcia-Ten, J.; Gozalbo, A.; Beltran, V.; Sanchez, J.; Sales, J.

    2010-07-01

    This study analyses, first, the influence of sodium carbonate content on the behaviour of the ceramic tile body composition during the different manufacturing process stages (preparation of the suspension, pressing, and firing), as well as on unfired tile mechanical strength. It has been verified that sodium carbonate can be used as a binder in ceramic tile compositions, since small percentages considerably enhance dry tile mechanical strength. It has furthermore been determined that for each composition there is an optimum addition content, with high increased mechanical strength (up to 70%), without this noticeably affecting the rheological behaviour of the suspension to be spray dried. These results are currently being patented (patent application P200930148). Once the binding effect of sodium carbonate had been verified, it was sought to establish its action mechanism. For this purpose, drops of mixtures of a standard ceramic composition and increasing quantities of sodium carbonate were prepared. The drops were rapidly dried and the granules were characterised by scanning electron microscopy. It was thus verified that the most likely sodium carbonate action mechanism was formation of solid bridges by crystallisation. (Author)

  17. Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature.

    Science.gov (United States)

    Qian, Jin; Shen, Mengmeng; Wang, Peifang; Wang, Chao; Li, Kun; Liu, Jingjing; Lu, Bianhe; Tian, Xin

    2017-09-01

    Powdered activated carbon (PAC), as an adsorbent, was applied to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Laboratory batch experiments were performed to investigate the influences of phosphate (P) competition, temperature, and pH for PFOS adsorption onto PAC. The results showed that higher temperature favored PFOS adsorption in single and binary systems. The kinetic data fitted very well to the pseudo second-order kinetic model. Thermodynamically, the endothermic enthalpy of the PFOS adsorption in single and binary systems were 125.07 and 21.25 kJ mol -1 , respectively. The entropy of the PFOS adsorption in single and binary systems were 0.479 and 0.092 kJ mol -1  K -1 , respectively. And the Gibbs constants were negative. These results indicated that the adsorption processes were spontaneous. The adsorption isotherms of PFOS agreed well with the Langmuir model. In the single system, PFOS adsorption decreased with increased pH value. The difference in the amount of PFOS adsorption between the single and binary systems increased at higher pH. Frustrated total internal reflection (FTIR) demonstrated that P competition increased the hydrophilicity of the PAC and the electrostatic repulsion between PFOS and PAC, then the PFOS adsorption amount decreased. It also demonstrated that, at higher temperature, increased PFOS adsorption was mainly due to the higher diffusion rate of PFOS molecules and greater number of active sites opened on the PAC surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Effects of carbon, nitrogen and ambient pH on patulin production and related gene expression in Penicillium expansum.

    Science.gov (United States)

    Zong, Yuanyuan; Li, Boqiang; Tian, Shiping

    2015-08-03

    Patulin, a potent mycotoxin which can cause serious health concerns, is mainly produced in foods by Penicillium expansum. Environmental factors play important roles in regulating biosynthesis of mycotoxins; however, information about the effects of environmental factors on patulin production and the involved mechanisms in P. expansum is limited. Here, we investigated the effects of different carbon (C) and nitrogen (N) sources, and ambient pH on patulin production in three P. expansum strains T01, M1 and Pe21, and the expression profile of 15 genes involved in patulin biosynthetic pathway. It was found that C and N sources and pH had great influence on patulin production in P. expansum. In general, patulin production of all three P. expansum strains showed similar trends under different C and N sources and pH conditions, though there were some differences in the optimal conditions among these strains. Glucose-containing sugars, complex N sources, and acidic conditions were favorable conditions for patulin production. The results of RT-qPCR showed that the relative expressions of most of the patulin genes were up-regulated under patulin-permissive conditions, indicating that patulin biosynthesis was mainly regulated at transcriptional level by these environmental factors. These findings will provide useful information to better understand the regulation mechanisms of patulin biosynthesis, and be helpful in developing effective means for controlling patulin contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

    Science.gov (United States)

    Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

    2012-11-01

    The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  20. Treatment of simulated wastewater containing Reactive Red 195 by zero-valent iron/activated carbon combined with microwave discharge electrodeless lamp/sodium hypochlorite.

    Science.gov (United States)

    Fu, Jie; Xu, Zhen; Li, Qing-Shan; Chen, Song; An, Shu-Qing; Zeng, Qing-Fu; Zhu, Hai-Liang

    2010-01-01

    A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon (ZVI/AC), microwave discharge electrodeless lamp/sodium hypochlorite (MDEL/NaClO) and the combination of ZVI/AC-MDEL/NaClO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaClO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaClO, we found that in the ZVI/AC-MEDL/NaClO process, ZVI/AC could break the azo bond firstly and then MEDL/NaClO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.

  1. Voltammetric determination of sudan ii in food samples at graphene modified glassy carbon electrode based on the enhancement effect of sodium dodecyl sulfate

    International Nuclear Information System (INIS)

    Ma, X.; Chen, M.; Chao, M.

    2013-01-01

    Summary: Herein, a novel electrochemical method was de veloped for the determination of Sudan II based on the electrochemical catalytic activity of graphene modified glassy carbon electrode (GME) and the enhancement effect of sodium dodecyl sulfate (SDS). In a pH 6.0 phosphate buffer solution, Sudan II exhibited a pair of well-defined quasi reversible redox peaks at the GME in the presence of 5.0x10/sup -5/ mol L/sup 1/ SDS. The oxidation peak current of Sudan II was linearly proportional to its concentration in a range from 4.0x10/sup -8/ to 4.0x10/sup -6/ mol L/sup 1/, with a linear regression equation of ipa (A) = 3.35 c + 5.96 x 10/sup -6/, r = 0.9988 and a detection limit of 8.0x10/sup -9/ mol L/sup 1/. The recoveries from the standards fortified blank samples were in the range of 94.7% to 97.5% with RSD lower than 4.0%. The novel method has been successfully used to determine Sudan II in food products with satisfactory results. (author)

  2. Mesoporous-activated carbon prepared from chitosan flakes via single-step sodium hydroxide activation for the adsorption of methylene blue.

    Science.gov (United States)

    Marrakchi, F; Ahmed, M J; Khanday, W A; Asif, M; Hameed, B H

    2017-05-01

    In this work, mesoporous-activated carbon (CSAC) was prepared from chitosan flakes (CS) via single-step sodium hydroxide activation for the adsorption of methylene blue (MB). CSAC was prepared using different impregnation ratios of NaOH:CS (1:1, 2:1, 3:1, and 4:1) at 800°C for 90min. The adsorption performance of CSAC was evaluated for MB at different adsorption variables, such MB initial concentrations (25-400mg/L), solution pH (3-11), and temperature (30-50°C). The adsorption isotherm data of CSAC-MB were well fitted to Langmuir model with a maximum adsorption capacity 143.53mg/g at 50°C. Best representation of kinetic data was obtained by the pseudo-second order model. CSAC exhibited excellent adsorption uptake for MB and can potentially be used for other cationic dyes. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Carbon dioxide, oxygen, and pH detection in animal adipose tissue by means of extracorporeal microdialysis

    Science.gov (United States)

    Baldini, F.; Bizzarri, A.; Cajlakovic, M.; Feichtner, F.; Gianesello, L.; Giannetti, A.; Gori, G.; Konrad, C.; Mencaglia, A. A.; Mori, E.; Pavoni, V.; Perna, A. M.; Trono, C.

    2007-05-01

    Atypical physiological symptoms can be developed in healthy people under critically ill conditions. pH, pO II and pCO II are informative indicators of the conditions of a living system and can be valuable in determining the physiologic status of the critically ill patients. The continuous monitoring of these small molecules into the interstitial fluid (ISF) is a promising approach to reduce diagnostic blood loss and painful stress associated with blood sampling. Microdialysis is the approach followed for the extraction of the sample from the subcutaneous adipose tissue; the drawn interstitial fluid flows through a microfluidic circuit formed by the microdialysis catheter in series with a glass capillary on the internal wall of which the appropriate chemistry for sensing is immobilised. Absorption changes for pH sensor and modulation of the fluorescence lifetime for pO II and pCO II are the working principle. Phenol red covalently bound into the internal wall of a glass capillary by means of the Mannich reaction and platinum(II) tetrakis-pentafluorophenyl-porphyrine entrapped within a polymerised polystyrene layer are the chemical transducers used for pH and oxygen detection; the ion pair 8- hydroxypyrene-1,3,6-trisulfonic acid trisodium salt/ tetraoctylammonium hydroxide, dissolved in a silicon-based polymeric matrix, is used for the carbon dioxide detection. A suitable hemorrhagic shock model was developed in order to validate clinically the developed sensors in the condition of extreme stress and the obtained results show that the adipose tissue can become an alternative site for the continuous oitoring of pH, pO II and pCO II.

  4. A high energy and power sodium-ion hybrid capacitor based on nitrogen-doped hollow carbon nanowires anode

    Science.gov (United States)

    Li, Dongdong; Ye, Chao; Chen, Xinzhi; Wang, Suqing; Wang, Haihui

    2018-04-01

    The sodium ion hybrid capacitor (SHC) has been attracting much attention. However, the SHC's power density is significantly confined to a low level due to the sluggish ion diffusion in the anode. Herein, we propose to use an electrode with a high double layer capacitance as the anode in the SHC instead of insertion anodes. To this aim, nitrogen doped hollow carbon nanowires (N-HCNWs) with a high specific surface area are prepared, and the high capacitive contribution during the sodium ion storage process is confirmed by a series of electrochemical measurements. A new SHC consisting of a N-HCNW anode and a commercial active carbon (AC) cathode is fabricated for the first time. Due to the hybrid charge storage mechanism combining ion insertion and capacitive process, the as-fabricated SHC strikes a balance between the energy density and power density, a energy density of 108 Wh kg-1 and a power density of 9 kW kg-1 can be achieved, which overwhelms the electrochemical performances of most reported AC-based SHCs.

  5. [Effect of sodium carbonate assisted hydrothermal process on heavy metals stabilization in medical waste incinerator fly ash].

    Science.gov (United States)

    Jin, Jian; Li, Xiao-dong; Chi, Yong; Yan, Jian-hua

    2010-04-01

    A sodium carbonate assisted hydrothermal process was induced to stabilize the fly ash from medical waste incinerator. The results showed that sodium carbonate assisted hydrothermal process reduced the heavy metals leachability of fly ash, and the heavy metal waste water from the process would not be a secondary pollution. The leachability of heavy metals studied in this paper were Cd 1.97 mg/L, Cr 1.56 mg/L, Cu 2.56 mg/L, Mn 17.30 mg/L, Ni 1.65 mg/L, Pb 1.56 mg/L and Zn 189.00 mg/L, and after hydrothermal process with the optimal experimental condition (Na2CO3/fly ash dosage = 5/20, reaction time = 8 h, L/S ratio = 10/1) the leachability reduced to < 0.02 mg/L for Cd, Cr, Cu, Mn, Ni, Pb, and 0.05 mg/L for Zn, according to GB 5085.3-2007. Meanwhile, the concentrations of heavy metals in effluent after hydrothermal process were less than 0.8 mg/L. The heavy metals leachability and concentration in effluent reduced with prolonged reaction time. Prolonged aging can affect the leachability of metals as solids become more crystalline, and heavy metals transferred inside of crystalline. The mechanism of heavy metal stabilization can be concluded to the co precipitation and adsorption effect of aluminosilicates formation, crystallization and aging process.

  6. Combined computational and biochemical study reveals the importance of electrostatic interactions between the "pH sensor" and the cation binding site of the sodium/proton antiporter NhaA of Escherichia coli.

    Science.gov (United States)

    Olkhova, Elena; Kozachkov, Lena; Padan, Etana; Michel, Hartmut

    2009-08-15

    Sodium proton antiporters are essential enzymes that catalyze the exchange of sodium ions for protons across biological membranes. The crystal structure of NhaA has provided a basis to explore the mechanism of ion exchange and its unique regulation by pH. Here, the mechanism of the pH activation of the antiporter is investigated through functional and computational studies of several variants with mutations in the ion-binding site (D163, D164). The most significant difference found computationally between the wild type antiporter and the active site variants, D163E and D164N, are low pK(a) values of Glu78 making them insensitive to pH. Although in the variant D163N the pK(a) of Glu78 is comparable to the physiological one, this variant cannot demonstrate the long-range electrostatic effect of Glu78 on the pH-dependent structural reorganization of trans-membrane helix X and, hence, is proposed to be inactive. In marked contrast, variant D164E remains sensitive to pH and can be activated by alkaline pH shift. Remarkably, as expected computationally and discovered here biochemically, D164E is viable and active in Na(+)/H(+) exchange albeit with increased apparent K(M). Our results unravel the unique electrostatic network of NhaA that connect the coupled clusters of the "pH sensor" with the binding site, which is crucial for pH activation of NhaA. 2009 Wiley-Liss, Inc.

  7. Studies of the pH dependence of 13C shifts and carbon-carbon coupling constants of [U-13C]aspartic and -glutamic acids

    International Nuclear Information System (INIS)

    London, R.E.; Walker, T.E.; Kollman, V.H.; Matwiyoff, N.A.

    1978-01-01

    13 C NMR studies of the chemical shifts and carbon--carbon spin--spin coupling constants of 90% [U- 13 C]aspartic and -glutamic acids are reported. Effects of titration of the two carboxyl groups are separated computationally and the results compared with those for asparagine and glutamine, aspartate and glutamate containing peptides, and a series of amino-n-butyric acids. The results indicate that the carboxyl carbon shift resulting from titration of the carboxyl group is strongly dependent on its distance (number of bonds) from an amino group. Alternatively, remote methyl groups exhibit a much smaller titration induced shift than carboxyl groups in the corresponding position. Significant remote effects of pH titration on the one-bond carbon-carbon coupling are also observed, particularly for couplings involving the side-chain carboxyl carbons. These results are discussed in terms of polarization of the C--O bonds in response to titration of a remote carboxyl group. Values of 3 J/sub CC/ in asparate and glutamate indicate a strong conformational dependence. Rotamer populations predicted on the basis of the observed couplings and theoretical INDO calculations are in good agreement with values based on analysis of the 3 J/sub HH/ and 3 J/sub CH/ couplings. For a given conformation of glutamic acid, it is found that 3 J 14 is considerably smaller than 3 J 25 . This result is consistent with obsrvations on a number of other 13 C-labeled amino acids. 5 figures, 4 tables

  8. Effect of the pH in the adsorption and in the immersion enthalpy of monohydroxylated phenols from aqueous solutions on activated carbons.

    Science.gov (United States)

    Blanco-Martínez, D A; Giraldo, L; Moreno-Piraján, J C

    2009-09-30

    An activated carbon Carbochem--PS230 was modified by chemical and thermal treatment in flow of H(2) in order to evaluate the influence of the activated carbon chemical surface in the adsorption of the monohydroxylated phenols. The solid-solution interaction was determined by analyzing the adsorption isotherms at 298 K at pH 7, 9 and 11 during 48 h. The adsorption capacity of activated carbons increases when the pH solution decreases. The amount adsorbed increases in the reduced carbon at the maximum adsorption pH and decreases in the oxidized carbon. In the sample of granulated activated carbon, CAG, the monohydroxylated phenols adsorption capacity diminishes in the following order catechol >hydroquinone >resorcinol, at the three pH values. The experimental data are evaluated with Freundlich's and Langmuir's models. The immersion enthalpies are determined and increase with the retained amount, ranging between 21.5 and 45.7 J g(-1). In addition, the immersion enthalpies show more interaction with the reduced activated carbon that has lower total acidity contents.

  9. The Effects of Voltage and Concentration of Sodium Bicarbonate on Electrochemical Synthesis of Ethanol from Carbon Dioxide Using Brass as Cathode

    Science.gov (United States)

    Ramadan, Septian; Fariduddin, Sholah; Rizki Aminudin, Afianti; Kurnia Hayatri, Antisa; Riyanto

    2017-11-01

    The effects of voltage and concentration of sodium bicarbonate were investigated to determine the optimum conditions of the electrochemical synthesis process to convert carbon dioxide into ethanol. The conversion process is carried out using a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor equipped with a cathode and anode. As the cathode was used brass, while as the anode carbon was utilized. Sample of the electrochemical synthesis process was analyzed by gas chromatography to determine the content of the compounds produced. The optimum electrochemical synthesis conditions to convert carbon dioxide into ethanol are voltage and concentration of sodium bicarbonate are 3 volts and 0.4 M with ethanol concentration of 1.33%.

  10. Roles of putative sodium-hydrogen antiporter (SHA) genes in S. coelicolor A3(2) culture with pH variation.

    Science.gov (United States)

    Kim, Yoon Jung; Moon, Myung Hee; Lee, Jae Sun; Hong, Soon-Kwang; Chang, Yong Keun

    2011-09-01

    Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative Na(+)/H(+) antiporter (sha) genes in S. coelicolor have been investigated in this study to elucidate the association of the sha on pH variation and secondary metabolism. Through the transcriptional analysis and overexpression experiments on 8 sha genes, we observed that most of the sha expressions were promoted by pH shock, and in the opposite way the pH changes and actinorhodin production were enhanced by the overexpression of each sha. We also confirmed that sha8 especially has a main role in maintaining cell viability and pH homeostasis through Na(+) extrusion, in salt effect experiment under the alkaline medium condition by deleting sha8. Moreover, this gene was observed to have a function of pH recovery after pH variation such as the pH shock, being able to cause the sporulation. However, actinorhodin production was not induced by the only pH recovery. The sha8 gene could confer on the host cell the ability to recover pH to the neutral level after pH variation like a pH drop. Sporulation was closely associated with this pH recovery caused by the action of sha8, whereas actinorhodin production was not due to such pH variation patterns alone.

  11. Potential role of sodium-proton exchangers in the low concentration arsenic trioxide-increased intracellular pH and cell proliferation.

    Directory of Open Access Journals (Sweden)

    Carmen Aravena

    Full Text Available Arsenic main inorganic compound is arsenic trioxide (ATO presented in solution mainly as arsenite. ATO increases intracellular pH (pHi, cell proliferation and tumor growth. Sodium-proton exchangers (NHEs modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 µmol/L, 0-48 hours in the absence or presence of 5-N,N-hexamethylene amiloride (HMA, 5-100 µmol/L, NHEs inhibitor, PD-98059 (30 µmol/L, MAPK1/2 inhibitor, Gö6976 (10 µmol/L, PKCα, βI and μ inhibitor, or Schering 28080 (10 µmol/L, H(+/K(+ATPase inhibitor plus concanamycin (0.1 µmol/L, V type ATPases inhibitor. Incorporation of [(3H]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescein loaded cells. The Na(+-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44(mapk were also determined. Lowest ATO (0.05 µmol/L, ~0.01 ppm used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or Gö6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1-like transport dependent-increased pHi requiring p42/44(mapk and PKCα, βI and/or μ activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and

  12. Electrochemical Corrosion Behavior of Carbon Steel and Hot Dip Galvanized Steel in Simulated Concrete Solution with Different pH Values

    Directory of Open Access Journals (Sweden)

    Wanchen XIE

    2017-08-01

    Full Text Available Hot dip galvanizing technology is now widely used as a method of protection for steel rebars. The corrosion behaviors of Q235 carbon steel and hot galvanized steel in a Ca(OH2 solution with a pH from 10 to 13 was investigated by electrode potential and polarization curves testing. The results indicated that carbon steel and hot galvanized steel were all passivated in a strong alkaline solution. The electrode potential of hot dip galvanized steel was lower than that of carbon steel; thus, hot dip galvanized steel can provide very good anodic protection for carbon steel. However, when the pH value reached 12.5, a polarity reversal occurred under the condition of a certain potential. Hot dip galvanized coating became a cathode, and the corrosion of carbon steel accelerated. The electrochemical behaviors and passivation abilities of hot dip galvanized steel and carbon steel were affected by pH. The higher the pH value was, the more easily they were passivated.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16675

  13. Potential phosphorus eutrophication mitigation strategy: Biochar carbon composition, thermal stability and pH influence phosphorus sorption.

    Science.gov (United States)

    Ngatia, L W; Hsieh, Y P; Nemours, D; Fu, R; Taylor, R W

    2017-08-01

    Phosphorus (P) eutrophication is a major pollution problem globally, with unprecedented amount of P emanating from agricultural sources. But little is known about the optimization of soil-biochar P sorption capacity. The study objective was to determine how biochar feedstocks and pyrolysis conditions influences carbon (C) thermal stability, C composition and pH and in turn influence the phosphorus sorption optimization. Biochar was produced from switchgrass, kudzu and Chinese tallow at 200, 300, 400, 500, 550, 650,750 °C. Carbon thermal stability was determined by multi-element scanning thermal analysis (MESTA), C composition was determined using solid state 13 C NMR. Phosphorus sorption was determined using a mixture of 10% biochar and 90% sandy soil after incubation. Results indicate increased P sorption (P biochar pyrolysis temperature. However, optimum P sorption was feedstock specific with switchgrass indicating P desorption between 200 and 550 °C. Phosphorus sorption was in the order of kudzu > switchgrass > Chinese tallow. Total C, C thermal stability, aromatic C and alkalinity increased with elevated pyrolysis temperature. Biochar alkalinity favored P sorption. There was a positive relationship between high thermal stable C and P sorption for Kudzu (r = 0.62; P = 0.0346) and Chinese tallow (r = 0.73; P = 0.0138). In conclusion, biochar has potential for P eutrophication mitigation, however, optimum biochar pyrolysis temperature for P sorption is feedstock specific and in some cases might be out of 300-500 °C temperature range commonly used for agronomic application. High thermal stable C dominated by aromatic C and alkaline pH seem to favor P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Biomass carbon micro/nano-structures derived from ramie fibers and corncobs as anode materials for lithium-ion and sodium-ion batteries

    International Nuclear Information System (INIS)

    Jiang, Qiang; Zhang, Zhenghao; Yin, Shengyu; Guo, Zaiping; Wang, Shiquan; Feng, Chuanqi

    2016-01-01

    Highlights: • Ramie fibers and corncobs are used as precursors to prepare the biomass carbons. • The ramie fiber carbon (RFC) took on morphology of 3D micro-rods. • The corncob carbon (CC) possessed a 2D nanosheets structure. • Both RFC and CC exhibited outstanding electrochemical performances in LIBs and SIBs systems. - Abstract: Three-dimensional (3D) rod-like carbon micro-structures derived from natural ramie fibers and two-dimensional (2D) carbon nanosheets derived from corncobs have been fabricated by heat treatment at 700 °C under argon atomsphere. The structure and morphology of the as-obtained ramie fiber carbon (RFC) and corncob carbon (CC) were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique. The electrochemical performances of the biomass carbon-based anode in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) were investigated. When tested as anode material for lithium ion batteries, both the RFC microrods and CC nanosheets exhibited high capacity, excellent rate capability, and stable cyclability. The specific capacity were still as high as 489 and 606 mAhg −1 after 180 cycles when cycled at room temperature in a 3.0–0.01 V potential (vs. Li/Li + ) window at current density of 100 mAg −1 , respectively, which are much higher than that of graphite (375 mAhg −1 ) under the same current density. Although the anodes in sodium ion batteries showed poorer specific capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 122 and 139 mAhg −1 with similar cycling stability. The feature of stable cycling performance makes the biomass carbon derived from natural ramie fibers and corncobs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries.

  15. Biomass carbon micro/nano-structures derived from ramie fibers and corncobs as anode materials for lithium-ion and sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Qiang; Zhang, Zhenghao [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Yin, Shengyu [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Guo, Zaiping [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Institute for Superconducting & Electronic Materials, University of Wollongong, NSW 2522 (Australia); Wang, Shiquan [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Feng, Chuanqi, E-mail: cfeng@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China)

    2016-08-30

    Highlights: • Ramie fibers and corncobs are used as precursors to prepare the biomass carbons. • The ramie fiber carbon (RFC) took on morphology of 3D micro-rods. • The corncob carbon (CC) possessed a 2D nanosheets structure. • Both RFC and CC exhibited outstanding electrochemical performances in LIBs and SIBs systems. - Abstract: Three-dimensional (3D) rod-like carbon micro-structures derived from natural ramie fibers and two-dimensional (2D) carbon nanosheets derived from corncobs have been fabricated by heat treatment at 700 °C under argon atomsphere. The structure and morphology of the as-obtained ramie fiber carbon (RFC) and corncob carbon (CC) were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique. The electrochemical performances of the biomass carbon-based anode in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) were investigated. When tested as anode material for lithium ion batteries, both the RFC microrods and CC nanosheets exhibited high capacity, excellent rate capability, and stable cyclability. The specific capacity were still as high as 489 and 606 mAhg{sup −1} after 180 cycles when cycled at room temperature in a 3.0–0.01 V potential (vs. Li/Li{sup +}) window at current density of 100 mAg{sup −1}, respectively, which are much higher than that of graphite (375 mAhg{sup −1}) under the same current density. Although the anodes in sodium ion batteries showed poorer specific capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 122 and 139 mAhg{sup −1} with similar cycling stability. The feature of stable cycling performance makes the biomass carbon derived from natural ramie fibers and corncobs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries.

  16. Relationship among salivary carbonic anhydrase VI activity and flow rate, biofilm pH and caries in primary dentition.

    Science.gov (United States)

    Frasseto, F; Parisotto, T M; Peres, R C R; Marques, M R; Line, S R P; Nobre Dos Santos, M

    2012-01-01

    This study aimed to determine the activity of carbonic anhydrase isoenzyme VI (CAVI) in the saliva of preschool children with caries and to investigate the relationship between caries and salivary CAVI activity, salivary flow rate and biofilm pH before and after a 20% sucrose rinse. Thirty preschool children aged 45.3-80.3 months were divided into two groups: a caries-free group and a caries group. Clinical examinations were conducted by one examiner (κ = 0.95) according to WHO criteria (dmfs) and early caries lesions. From each subject, CAVI activity, salivary flow rate and plaque pH were determined before and after a sucrose rinse. The results were submitted to Wilcoxon, Mann-Whitney and Spearman correlation tests (α = 0.05). The results showed that prerinse CAVI activity and its variation were higher in the saliva from caries children than from caries-free children. No difference was found between the two groups in postrinse salivary CAVI activity. After rinsing, biofilm pH differences were lower in both groups (p = 0.0012 and p = 0.0037 for the caries and caries-free groups, respectively). Also, after the sucrose rinse, salivary flow rate significantly increased in caries and caries-free groups (p = 0.0003, p = 0.0037). The variation of salivary CAVI activity was negatively correlated with caries (r = -0.501, p = 0.005). Child's age showed a positive correlation with caries (r = 0.456, p = 0.011). These results suggest that variation of salivary CAVI activity and child's age are associated with dental caries in preschool children. Copyright © 2012 S. Karger AG, Basel.

  17. Study of new complexes of uranium and comba radical. I.- Complexes defective in sodium carbonate; Estudio de nuevos complejos entre el uranio y el radical CDMBA. I. Complejos con defectos de carbonato sodico

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Galiano Sedano, J A; Parellada Bellod, R; Bellido Gonzalez, A

    1975-07-01

    Some complexes formed in presence of defect of sodium carbonate with respect to the stoichiometric ratio (U): (C0{sub 3}) = 1:3 are studied. This ratio corresponds to the main complex which is responsible for the uranium extraction with CDMBAC organic solutions and from U(VI) aqueous solutions with an excess of sodium carbonate. (Author) 10 refs.

  18. Microwave assisted synthesis of cyclic carbonates from olefins with sodium bicarbonates as the C1 source.

    Science.gov (United States)

    Yang, Xiaoqing; Wu, Jie; Mao, Xianwen; Jamison, Timothy F; Hatton, T Alan

    2014-03-25

    An effective transformation of alkenes into cyclic carbonates has been achieved using NaHCO3 as the C1 source in acetone-water under microwave heating, with selectivities and yields significantly surpassing those obtained using conventional heating.

  19. An Amorphous Carbon Nitride Composite Derived from ZIF-8 as Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Fan, Jing-Min; Chen, Jia-Jia; Zhang, Qian; Chen, Bin-Bin; Zang, Jun; Zheng, Ming-Sen; Dong, Quan-Feng

    2015-06-08

    An composite comprising amorphous carbon nitride (ACN) and zinc oxide is derived from ZIF-8 by pyrolysis. The composite is a promising anode material for sodium-ion batteries. The nitrogen content of the ACN composite is as high as 20.4 %, and the bonding state of nitrogen is mostly pyridinic, as determined by X-ray photoelectron spectroscopy (XPS). The composite exhibits an excellent Na(+) storage performance with a reversible capacity of 430 mA h g(-1) and 146 mA h g(-1) at current densities of 83 mA g(-1) and 8.33 A g(-1) , respectively. A specific capacity of 175 mA h g(-1) was maintained after 2000 cycles at 1.67 A g(-1) , with only 0.016 % capacity degradation per cycle. Moreover, an accelerating rate calorimetry (ARC) test demonstrates the excellent thermal stability of the composite, with a low self heating rate and high onset temperature (210 °C). These results shows its promise as a candidate material for high-capacity, high-rate anodes for sodium-ion batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Immediate acid-suppressing effects of ranitidine hydrochloride and rabeprazole sodium following initial administration and reintroduction: A randomized, cross-over study using wireless pH monitoring capsules.

    Science.gov (United States)

    Ono, Shouko; Kato, Mototsugu; Ono, Yuji; Imai, Aki; Yoshida, Takeshi; Shimizu, Yuichi; Asaka, Masahiro

    2009-04-01

    Histamine 2 receptor antagonists and proton-pump inhibitors, drugs that are widely used for the treatment of acid-related diseases, have different clinical characteristics. The objective of this study was to compare the acid-suppressing effects of ranitidine hydrochloride and those of rabeprazole sodium at the first administration and re-administration after withdrawal. The study was designed as an open-label, randomized, two-way cross-over trial. Seven Helicobacter pylori-negative healthy volunteers were enrolled in this study. Ranitidine hydrochloride (300 mg/day) or rabeprazole sodium (20 mg/day) was administered from days 1 to 7 and from days 11 to 13. The percentage of time with gastric pH sodium maintained a potent and stable effect from days 2 to 7 (ranitidine vs rabeprazole: P hydrochloride was attenuated after day 4. In addition, the effect of ranitidine hydrochloride at re-administration was attenuated (days 11, 12, and 13 vs pre-administration: not significant). In view of our observations, we expect symptoms associated with gastric acidity to be more adequately controlled with rabeprazole sodium in the short term when compared to ranitidine hydrochloride.

  1. Sustained release of simvastatin from hollow carbonated hydroxyapatite microspheres prepared by aspartic acid and sodium dodecyl sulfate.

    Science.gov (United States)

    Wang, Ke; Wang, Yinjing; Zhao, Xu; Li, Yi; Yang, Tao; Zhang, Xue; Wu, Xiaoguang

    2017-06-01

    Hollow carbonated hydroxyapatite (HCHAp) microspheres as simvastatin (SV) sustained-release vehicles were fabricated through a novel and simple one-step biomimetic strategy. Firstly, hollow CaCO 3 microspheres were precipitated through the reaction of CaCl 2 with Na 2 CO 3 in the presence of aspartic acid and sodium dodecyl sulfate. Then, the as-prepared hollow CaCO 3 microspheres were transformed into HCHAp microspheres with a controlled anion-exchange method. The HCHAp microspheres were 3-5μm with a shell thickness of 0.5-1μm and were constructed of short needle nanoparticles. The HCHAp microspheres were then loaded with SV, exhibiting excellent drug-loading capacity and sustained release properties. These results present a new material synthesis strategy for HCHAp microspheres and suggest that the as-prepared HCHAp microspheres are promising for applications in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. The Effect of DNA and Sodium Cholate Dispersed Single-Walled Carbon Nano tubes on the Green Algae Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Williams, R.M.; Cox, Z.; Dolash, B.D.; Sooter, L.J.; Williams, R.M.; Taylor, H.K.; Thomas, J.

    2014-01-01

    Increasing use of single-walled carbon nano tubes (SWCNTs) will lead to their increased release into the environment. Previous work has shown negative effects of SWCNT on growth and survival of model organisms. The aim of the current study was to determine the effect of SWCNT well-dispersed by either DNA or sodium cholate (SC) on the unicellular green algae Chlamydomonas reinhardtii in stagnant water conditions. Growth measurements were taken up to ten days for algae treated with varied levels of DNA:SWCNT or SC:SWCNT or controls, and chlorophyll content after 10 days was determined. Results show no effect on either growth or chlorophyll content of algae at any concentration or duration. This is in contradiction to prior work showing toxicity of SWCNT to environmental model organisms.

  3. Physicochemical properties, firmness, and nanostructures of sodium carbonate-soluble pectin of 2 Chinese cherry cultivars at 2 ripening stages.

    Science.gov (United States)

    Zhang, Lifen; Chen, Fusheng; An, Hongjie; Yang, Hongshun; Sun, Xiaoyang; Guo, Xingfeng; Li, Lite

    2008-08-01

    Firmness and physicochemical properties of 2 Chinese cherry (Prunus pseudocerasus L.) cultivars (soft cultivar "Caode" and crisp cultivar "Bende") at unripe and ripe stages were investigated, and the qualitative and quantitative information about sodium carbonate-soluble pectin (SSP) nanostructures was determined by atomic force microscopy (AFM). The lengths and widths of the cherry SSPs are very regular: almost all of the widths and lengths of SSP single molecules are composed of several basic units. The widths of the SSP chains are 37, 47, 55, and 61 nm, and the lengths are 123, 202, and 380 nm in both cultivars. The results show that the firmer cherry groups (crisp fruit) contain more percentages of wide and short SSP chains than soft fruit, and the unripe groups contain more percentages of wide and long SSP chains than corresponding ripe groups. They indicate that those nanostructural characteristics of SSP are closely related with firmness of the Chinese cherries in each cultivar.

  4. In vitro study of the effect of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate on acid-softened enamel.

    Science.gov (United States)

    Rege, Aarti; Heu, Rod; Stranick, Michael; Sullivan, Richard J

    2014-01-01

    To investigate the possible mode of action of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and sodium monofluorophosphate in delivering the benefits of preventing acid erosion and rehardening acid-softened enamel. The surfaces of acid-softened bovine enamel specimens were evaluated after application of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate in vitro. Scanning Electron Microscopy (SEM), Electronic Spectrometry for Chemical Analysis (ESCA), and Secondary Ion Mass Spectrometry (SIMS) were used to characterize the enamel surfaces. Exposure of pristine enamel surfaces to citric acid resulted in clear roughening of the surface. Multiple applications of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to the surface of the enamel resulted in the disappearance of the microscopic voids observed by SEM as a function of treatment applications. The ESCA analysis demonstrated that both the nitrogen and carbonate levels increased as the number of treatments increased, which provides evidence that arginine and calcium carbonate were bound to the surface. Observance of arginine's signature mass fragmentation pattern by SIMS analysis confirmed the identity of arginine on the enamel surface. A series of in vitro experiments has demonstrated a possible mode of action by which a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate delivers the benefits of preventing acid erosion and rehardening acid-softened enamel. The combination of arginine and calcium carbonate adheres to the enamel surface and helps to fill the microscopic gaps created by acid, which in turn helps repair the enamel and provides a protective coating against future acid attacks.

  5. Nitrogen-rich functional groups carbon nanoparticles based fluorescent pH sensor with broad-range responding for environmental and live cells applications.

    Science.gov (United States)

    Shi, Bingfang; Su, Yubin; Zhang, Liangliang; Liu, Rongjun; Huang, Mengjiao; Zhao, Shulin

    2016-08-15

    A nitrogen-rich functional groups carbon nanoparticles (N-CNs) based fluorescent pH sensor with a broad-range responding was prepared by one-pot hydrothermal treatment of melamine and triethanolamine. The as-prepared N-CNs exhibited excellent photoluminesence properties with an absolute quantum yield (QY) of 11.0%. Furthermore, the N-CNs possessed a broad-range pH response. The linear pH response range was 3.0 to 12.0, which is much wider than that of previously reported fluorescent pH sensors. The possible mechanism for the pH-sensitive response of the N-CNs was ascribed to photoinduced electron transfer (PET). Cell toxicity experiment showed that the as-prepared N-CNs exhibited low cytotoxicity and excellent biocompatibility with the cell viabilities of more than 87%. The proposed N-CNs-based pH sensor was used for pH monitoring of environmental water samples, and pH fluorescence imaging of live T24 cells. The N-CNs is promising as a convenient and general fluorescent pH sensor for environmental monitoring and bioimaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The influence of activating agents on the performance of rice husk-based carbon for sodium lauryl sulfate and chrome (Cr) metal adsorptions

    Science.gov (United States)

    Arneli; Safitri, Z. F.; Pangestika, A. W.; Fauziah, F.; Wahyuningrum, V. N.; Astuti, Y.

    2017-02-01

    This research aims to study the influence of activating agents to produce rice husk based-carbon with high adsorption capacity and efficiency for either hazardous organic molecules or heavy metals which are unfriendly for the environment. Firstly, rice husk was burned by pyrolysis at different temperatures to produce rice husk-based carbon. To improve its ability as an adsorbent, carbon was treated with activating agents, namely, H3PO4 and KOH at room and high temperature (420 °C). The performance of carbon was then tested by contacting it with surfactant (SLS). Finally, the surfactant-modified active carbon was applied for chrome metal removal. The result shows that activation of carbon using phosphate acid (H3PO4) was more effective than potassium hydroxide (KOH) conducted at high temperature to adsorb sodium lauryl sulfate (SLS) and chrome metal with the adsorption capacity 1.50 mgg-1 and 0.375 mgg-1, respectively.

  7. Adsorption of Carbon Dioxide on Sodium and Potassium Forms of STI Zeolite

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Zones, S. I.; Kubů, Martin; Davis, T. M.; Čejka, Jiří

    2012-01-01

    Roč. 77, č. 8 (2012), s. 675-681 ISSN 2192-6506 R&D Projects: GA ČR GA203/08/0604 Institutional support: RVO:61388955 Keywords : adsorption * carbon dioxide * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry

  8. Pyrolytic Carbon Nanosheets for Ultrafast and Ultrastable Sodium-Ion Storage.

    Science.gov (United States)

    Cho, Se Youn; Kang, Minjee; Choi, Jaewon; Lee, Min Eui; Yoon, Hyeon Ji; Kim, Hae Jin; Leal, Cecilia; Lee, Sungho; Jin, Hyoung-Joon; Yun, Young Soo

    2018-04-01

    Na-ion cointercalation in the graphite host structure in a glyme-based electrolyte represents a new possibility for using carbon-based materials (CMs) as anodes for Na-ion storage. However, local microstructures and nanoscale morphological features in CMs affect their electrochemical performances; they require intensive studies to achieve high levels of Na-ion storage performances. Here, pyrolytic carbon nanosheets (PCNs) composed of multitudinous graphitic nanocrystals are prepared from renewable bioresources by heating. In particular, PCN-2800 prepared by heating at 2800 °C has a distinctive sp 2 carbon bonding nature, crystalline domain size of ≈44.2 Å, and high electrical conductivity of ≈320 S cm -1 , presenting significantly high rate capability at 600 C (60 A g -1 ) and stable cycling behaviors over 40 000 cycles as an anode for Na-ion storage. The results of this study show the unusual graphitization behaviors of a char-type carbon precursor and exceptionally high rate and cycling performances of the resulting graphitic material, PCN-2800, even surpassing those of supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. One-dimensional coaxial Sb and carbon fibers with enhanced electrochemical performance for sodium-ion batteries

    Science.gov (United States)

    Zhu, Mengnan; Kong, Xiangzhong; Yang, Hulin; Zhu, Ting; Liang, Shuquan; Pan, Anqiang

    2018-01-01

    Antimony (Sb) has been intensively investigated as a promising anode material for sodium ion batteries (SIBs) in recent years. However, bulk Sb particles usually suffer from excessive volume expansion thus leading to dramatic capacity decay after cycling. To address this issue, Sb has been uniformly decorated on Polyacrylonitrile (PAN) derived carbon nanofibers (PCFs) via a simple chemical deposition strategy to form a one-dimensional (1D) core-shell nanostructure of Sb@PCFs. PCFs were first derived from electrospun PAN fibers and treated with subsequent calcination. The PCFs constructed an interwoven carbon network were later employed for Sb deposition, which can effectively alleviate aggregation or further cracking of Sb nanoparticles occurred in electrochemical kinetic process. The as-obtained Sb@PCFs nanocomposites demonstrated excellent cycling stability with good rate performances. This carefully designed core-shell nanostructure of antimony nanoparticles wrapped PCFs are responsible for good electrochemical Na-ion storage. Moreover, the 1D nanostructure manage to pave pathways for fast ions transfer during charge-discharge, which could extra contribute to the enhanced SIBs performances.

  10. Study of Activated Carbons by Pyrolysis of Mangifera Indica Seed (Mango in Presence of Sodium and Potassium Hydroxide

    Directory of Open Access Journals (Sweden)

    J. C. Moreno-Piraján

    2012-01-01

    Full Text Available Activated carbons (ACs were prepared by pyrolysis of seeds mango in presence of sodium and potassium hydroxide (chemical activities. Seeds mango from Colombian Mango cultives were impregnated with aqueous solutions of NaOH and KOH following a variant of the incipient wetness method. Different concentrations were used to produce impregnation ratios of 3:1 (weight terms. Activation was carried out under argon flow by heating to 823 K with 1 h soaking time. The porous texture of the obtained ACs was characterized by physical adsorptions of N2 at 77 K and CO2 at 273 K. The impregnation ration and hydroxide type had a strong influence on the pore structure of these ACs, which could be easily controlled by simply varying the proportion of the hydroxides used in the activation. Thus, the development of porosity for precursors with low structural order (high reactivity is better with NaOH than KOH, whereas the opposite is observed for the highly ordered ones. Variable adsorption capacities and porosity distributions can be achieved depending on the activating agent selected. In general, KOH produces activated carbons with narrower micropore distributions than those prepared by NaOH.

  11. The anodic dissolution of SIMFUEL (UO{sub 2}) in slightly alkaline sodium carbonate/bicarbonate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Keech, P.G.; Goldik, J.S.; Qin, Z. [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.ca [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London ON, N6A 5B7 (Canada)

    2011-09-30

    The corrosion of nuclear fuel under waste disposal conditions is likely to be influenced by the bicarbonate/carbonate content of the groundwater since it increases the solubility of the U{sup VI} corrosion product, [UO{sub 2}]{sup 2+}. As one of the half reactions involved in the corrosion process, the anodic dissolution of SIMFUEL (UO{sub 2}) has been studied in bicarbonate/carbonate solutions (pH 9.8) using voltammetric and potentiostatic techniques and electrochemical impedance spectroscopy. The reaction proceeds by two consecutive one electron transfer reactions (U{sup IV} {yields} U{sup V} {yields} U{sup VI}). At low potentials ({<=}250 mV (vs. SCE) the rate of the first electron transfer reaction is rate determining irrespective of the total carbonate concentration. At potentials >250 mV (vs. SCE) the formation of a U{sup VI}O{sub 2}CO{sub 3} surface layer begins to inhibit the dissolution rate and the current becomes independent of potential indicating rate control by the chemical dissolution of this layer.

  12. A comparative clinical study investigating the efficacy of a test dentifrice containing 8% strontium acetate and 1040 ppm sodium fluoride versus a marketed control dentifrice containing 8% arginine, calcium carbonate, and 1450 ppm sodium monofluorophosphate in reducing dentinal hypersensitivity.

    Science.gov (United States)

    Hughes, Nathan; Mason, Stephen; Jeffery, Peter; Welton, Helen; Tobin, Maira; O'Shea, Caoimhe; Browne, Mairead

    2010-01-01

    The objective of this clinical study was to evaluate and compare the efficacy in reducing dentin hypersensitivity of an 8% strontium acetate, 1040 ppm sodium fluoride dentifrice to a marketed control 8% arginine, calcium carbonate, 1450 ppm sodium monofluorophosphate dentifrice after twice-daily brushing for two, four, and eight weeks. This was a randomized, examiner-blind, two-arm parallel group, eight-week longitudinal clinical study with seventy-nine subjects, stratified based on baseline tooth sensitivity (Schiff score, Yeaple). Subjects brushed with either an 8% strontium acetate-based dentifrice or a marketed 8% arginine calcium carbonate dentifrice twice daily for approximately one minute. At screening, baseline, weeks two, four, and eight, subjects' tooth sensitivity was determined through both evaporative (Schiff and Visual Analogue Scale [VAS]) and tactile stimuli (Yeaple probe). Subject assessments using each stimulus were performed by the same examiner throughout the study. Seventy-seven subjects completed this clinical study. Both subject groups exhibited significant cumulative reductions from baseline to Days 14, 28, and 56 in dentin hypersensitivity as measured by Schiff, Yeaple, and VAS (for the 8% strontium acetate group, p carbonate group, p = 0.0031 for Yeaple at Day 14, p = 0.0015 for VAS at Day 14, and p 0.05) were observed between treatments for any of the time points and measures except for tactile sensitivity at Day 56, for which the 8% strontium acetate-based dentifrice was statistically superior (p = 0.0391) to the control 8% arginine calcium carbonate dentifrice. The 8% strontium acetate, 1040 ppm sodium fluoride dentifrice provided significant reductions in dentin hypersensitivity (p carbonate dentifrice showed no significant differences (p > 0.05) apart from tactile (Yeaple) sensitivity at week 8, where the 8% strontium acetate-based dentifrice showed significant improvement over the control (p = 0.0391).

  13. Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies.

    Directory of Open Access Journals (Sweden)

    David I Kline

    Full Text Available Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC and total alkalinity (TA, rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 - 6.6°C and lowest diel ranges (0.9 - 3.2°C were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 - 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall to December (end of Spring. Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems.

  14. Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies.

    Science.gov (United States)

    Kline, David I; Teneva, Lida; Hauri, Claudine; Schneider, Kenneth; Miard, Thomas; Chai, Aaron; Marker, Malcolm; Dunbar, Rob; Caldeira, Ken; Lazar, Boaz; Rivlin, Tanya; Mitchell, Brian Gregory; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-01-01

    Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC) and total alkalinity (TA), rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 - 6.6°C) and lowest diel ranges (0.9 - 3.2°C) were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 - 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall) to December (end of Spring). Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems.

  15. Effect of surface chemistry, solution pH, and ionic strength on the removal of herbicides diuron and amitrole from water by an activated carbon fiber.

    Science.gov (United States)

    Fontecha-Cámara, M A; López-Ramón, M V; Alvarez-Merino, M A; Moreno-Castilla, C

    2007-01-30

    A study was conducted on the effects of carbon surface chemistry, solution pH, and ionic strength on the removal of diuron and amitrole from aqueous solutions by adsorption on an as-received and oxidized activated carbon fiber. Results obtained were explained by the surface characteristics of the adsorbents and the characteristics of the herbicide molecules. Under the experimental conditions used, diuron uptake was much higher than that of amitrole, despite its larger molecular dimensions, due to the lesser water solubility, greater hydrophobicity, and larger dipolar moment of diuron compared with amitrole. Uptake variations associated with differences in carbon surface oxidation, solution pH, and ionic strength were explained by corresponding changes in electrostatic, hydrophobic, and van der Waals interactions.

  16. Electrochemical Performance of Electrospun carbon nanofibers as free-standing and binder-free anodes for Sodium-Ion and Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Jin, Juan; Shi, Zhi-qiang; Wang, Cheng-yang

    2014-01-01

    Highlights: • Electrospun carbon nanofiber webs were prepared by pyrolysis of polyacrylonitrile. • The webs as binder-free and current collector-free electrodes for SIBs and LIBs. • Different layer spacing and pore size for Li and Na lead different electrochemical behavior. • Electrochemical performances of the electrodes were high. - Abstract: A series of hard carbon nanofiber-based electrodes derived from electrospun polyacrylonitrile (PAN) nanofibers (PAN-CNFs) have been fabricated by stabilization in air at about 280 °C and then carbonization in N 2 at heat treatment temperatures (HTT) between 800 and 1500 °C. The electrochemical performances of the binder-free, current collector-free carbon nanofiber-based anodes in lithium-ion batteries and sodium-ion batteries are systematically investigated and compared. We demonstrate the presence of similar alkali metal insertion mechanisms in both cases, but just the differences of the layer spacing and pore size available for lithium and sodium ion lead the discharge capacity delivered at sloping region and plateau region to vary from the kinds of alkali elements. Although the anodes in sodium-ion batteries show poorer rate capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 275 mAh g −1 and similar cycling stability due to the conductive 3-D network, weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets. The feature of high capacity and stable cycling performance makes PAN-CNFs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries

  17. Determination of antihypertensive drug moexipril hydrochloride based on the enhancement effect of sodium dodecyl sulfate at carbon paste electrode.

    Science.gov (United States)

    Attia, Ali K

    2010-04-15

    Herein, an electrochemical differential pulse voltammetric method was developed for the determination of moexipril hydrochloride based on the enhancement effect of sodium dodecyl sulfate. The oxidation process has been carried out in Britton-Robinson buffer. Moexipril hydrochloride exhibits a well-defined irreversible oxidation peak over the entire pH range (2-11). The peak current varied linearly over the range from 4.0 x 10(-7) to 5.2 x 10(-6) mol L(-1). The limits of detection and quantification were 6.87 x 10(-8) mol L(-1) and 2.29 x 10(-7) mol L(-1), respectively. The recovery was found in the range from 99.65% to 100.76%. The relative standard deviation was found in the range from 0.429% to 0.845%. The proposed method possesses high sensitivity, accuracy and rapid response. Finally, this method was successfully used to determine moexipril hydrochloride in tablets. (c) 2009 Elsevier B.V. All rights reserved.

  18. Contribution to the simultaneous determination of several light elements in alkalin metals by gamma photon and charged particle activation. Application to carbon and nitrogen determination in sodium

    International Nuclear Information System (INIS)

    Bock, Patrice.

    1976-10-01

    A new γ activation method for the simultaneous determination of carbon and nitrogen in sodium is described. It makes use of the nuclear reactions: 12 C(γ,n) 11 C and 14 N(γ,n) 13 N. The process used to separate carbone-11 and nitrogen-13 from sodium with a view to their radio-activity determination is based on vacuum dissolution of the sample in a mixture of oxidizing and acid fused salts. The oxidized carbon is trapped as CO 2 on soda asbestos and the nitrogen as N 2 on molecular sieve at -196 deg C. The efficiency of the technique is estimated by means of tracer tests and by proton activation. The relative influence of competitive nuclear reactions on elements close to the above two impurities, or even on the matrix itself, is examined. The method described has a theoretical detection limit of some 10 -8 g.g -1 for the two elements in question and mean concentrations of 0.3+-0.1x10 -6 g.g -1 carbon and 1.0+-0.5x10 -6 g.g -1 nitrogen have in fact been measured in a batch of 0.5 g sodium samples [fr

  19. Experimental Study of Effects of pH, Temperature and H2O2 on Gasoline Removal from Contaminated Water Using Granular Activated Carbon

    Directory of Open Access Journals (Sweden)

    Hasti Hasheminejad

    2010-01-01

    Full Text Available Contamination of water with petroleum compounds is a serious environmental problem in Iran. Old fuel storage tanks, gasoline stations, and oil refineries are the main sources of gasoline leakage into water resources. In this study, the batch adsorption technique was used to investigate adsorption of petroleum compounds (gasoline on granular activated carbon. Experiments showed that the adsorption capacity of activated carbon is a function of pH, temperature, and H2O2 concentration in solution. Maximum adsorption of petroleum compounds was obtained at pH of 8. Adsorption of petroleum compounds was increased by decreasing temperature (due to decreasing van der Waals forces between the adsorbent and the adsorbate and H2O2 concentration in solution (due to the decrease in the initial concentration of the adsorbate by oxidation . In this experiment, the maximum equilibrium capacity of granular activated carbon was 129.05 mg COD/g GAC at pH 8 and at an ambient temperature of 10˚C. The experimental adsorption data were fitted to the Freundlich and Langmuir adsorption model. The correlation coefficients calculated indicate that the Freundlich model was best fitted. Also, the regression analysis was used with a correlation coefficient of 0.981 to develop a model for describing the relationship between absorption variation in equilibrium state, pH, temperature, and H2O2. On the whole, the correlation coefficient calculated by the proposed model was found to be higher than Freundlich’s.

  20. Effect of Sodium Sulfide on Ni-Containing Carbon Monoxide Dehydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Jian Feng; Paul A. Lindahl

    2004-07-28

    OAK-B135 The structure of the active-site C-cluster in CO dehydrogenase from Carboxythermus hydrogenoformans includes a {mu}{sup 2}-sulfide ion bridged to the Ni and unique Fe, while the same cluster in enzymes from Rhodospirillum rubrum (CODH{sub Rr}) and Moorella thermoacetica (CODH{sub Mt}) lack this ion. This difference was investigated by exploring the effects of sodium sulfide on activity and spectral properties. Sulfide partially inhibited the CO oxidation activity of CODH{sub Rr} and generated a lag prior to steady-state. CODH{sub Mt} was inhibited similarly but without a lag. Adding sulfide to CODH{sub Mt} in the C{sub red1} state caused the g{sub av} = 1.82 EPR signal to decline and new features to appear, including one with g = 1.95, 1.85 and (1.70 or 1.62). Removing sulfide caused the g{sub av} = 1.82 signal to reappear and activity to recover. Sulfide did not affect the g{sub av} = 1.86 signal from the C{sub red2} state. A model was developed in which sulfide binds reversibly to C{sub red1}, inhibiting catalysis. Reducing this adduct causes sulfide to dissociate, C{sub red2} to develop, and activity to recover. Using this model, apparent K{sub I} values are 40 {+-} 10 nM for CODH{sub Rr} and 60 {+-} 30 {micro}M for CODH{sub Mt}. Effects of sulfide are analogous to those of other anions, including the substrate hydroxyl group, suggesting that these ions also bridge the Ni and unique Fe. This proposed arrangement raises the possibility that CO binding labilizes the bridging hydroxyl and increases its nucleophilic tendency towards attacking Ni-bound carbonyl.

  1. Enhancement of uranium loading on ion exchange resin from carbonate leachate by lowering pH from 8 to 6.5

    International Nuclear Information System (INIS)

    Otto, J.B.

    1984-01-01

    This paper discusses a laboratory study that shows the saturation ion-exchange loading of uranium from carbonate leachate can be doubled by lowering the pH of the leachate from 8 to 6.5. Small column and batch resin loading tests using Dowex 21K ion-exchange resin are described. The leachate contained 3,300 ppm chloride, 2,400 ppm carbonate, and 220 ppm U 3 O 8 , and had a pH of 8. Even at this rather mild salinity the saturation ion-exchange loading was found to be only about 3 to 4 lbm U 3 O 8 /cu ft resin (48 to 64 g/dm 3 ) because of competition with the chloride ion for exchange sites on the anionic resin. Lowering the pH of the leachate to 6.5 by CO 2 gas addition, however, increased loading to about 8 lbm U 3 O 8 /cu ft resin (128 g/dm 3 ). The pH-lowering effect worked especially well at relatively high salt concentration. The same leachate, with its chloride content increased to 12,000 ppm, loaded only 0.5 lbm U 3 O 8 /cu ft resin (8 g/dm 3 ) at pH 8 but loaded 5.5 lbm U 3 O 8 /cu ft resin (88 g/dm 3 ) at pH 6.5

  2. Efeitos de meio de cultura, fontes de carbono e nitrogênio, pH e regime luminoso no crescimento de Mycosphaerella musicola Effects of medium, carbon and nitrogen source, pH and light on the growth of Mycosphaerella musicola

    Directory of Open Access Journals (Sweden)

    Angélica Virgínia Valois Montarroyos

    2007-03-01

    Full Text Available Este trabalho objetivou o estabelecimento de condições favoráveis ao crescimento micelial de M. musicola in vitro, pela avaliação em quatro experimentos, da influência de diferentes meios de cultura (BDA, BDA/IFB, V8, V8/IFB, V8/CaCO3 e V8/CaCO3/IFB; combinações de fontes de carbono (dextrose, maltose, sacarose e xilose e nitrogênio (peptona, glicina, nitrato de potássio e de sódio; valores de pH (6,8; 6,4; 5,7 e 4,9 e regimes luminosos (escuro contínuo, alternância luminosa e claro contínuo. Observou-se um maior crescimento de M. musicola quando cultivado nos meios de cultura BDA/IFB, V8/IFB e BDA. As fontes de carbono sacarose, maltose e dextrose quando combinadas com a peptona como fonte de nitrogênio, promoveram um maior crescimento micelial de M. musicola. O meio de cultura BDA/IFB, com o valor final de pH ajustado para 5,7, em regime de escuro contínuo, apresentou-se como o melhor para o crescimento de M. musicola.This work aimed the establishment of the best growth conditions of M. musicola mycelia in vitro through the analysis of the influence of different culture media (BDA, BDA/IFB, V8, V8/IFB, V8/CaCO3 and V8/CaCO3/IFB, combinations of carbon (dextrose, maltose, sucrose and xylose and nitrogen (peptone, glycine, potassium nitrate and sodium nitrate sources, medium pH values (6.8, 6.4, 5.7 and 4.9 and photoperiods (continuous darkness, alternating darkness/lightness and continuous lightness. At the end of the evaluation period, cultural parameters and the dry weights of colonies were annotated. BDA/IFB, V8/IFB and BDA culture media promoted the best mycelial growth. The experiments also demonstrated that dextrose and sucrose when combined with peptose as a nitrogen source, are the best carbon sources as they promoted the most vigorous mycelial growth. The use of BDA/IFB culture medium, with its final pH adjusted to 5.7, and a photoperiod of continuous darkness was the best condition for the growth of M. musicola.

  3. DFT investigation of NH_3, PH_3, and AsH_3 adsorptions on Sc-, Ti-, V-, and Cr-doped single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Buasaeng, Prayut; Rakrai, Wandee; Wanno, Banchob; Tabtimsai, Chanukorn

    2017-01-01

    Highlights: • Transition metal-doped single wall carbon nanotubes and their adsorption with NH_3, PH_3 and AsH_3 molecules were investigated using a DFT method. • Adsorptions of NH_3, PH_3 and AsH_3 molecules on pristine single wall carbon nanotubeswere improved by transition metal doping. • Structural and electronic properties of single wall carbon nanotubes were significantly changed by transition metal doping and gas adsorptions. - Abstract: The adsorption properties of ammonia (NH_3), phosphine (PH_3), and arsine (AsH_3) on pristine and transition metal- (TM = Sc, Ti, V, and Cr) doped (5,5) armchair single-walled carbon nanotubes (SWCNTs) were theoretically investigated. The geometric and electronic properties and adsorption abilities for the most stable configuration of NH_3, PH_3, and AsH_3 adsorptions on pristine and TM-doped SWCNTs were calculated. It was found that the binding abilities of TMs to the SWCNT were in the order: Cr > V > Sc > Ti. However, the adsorption energy showed that the pristine SWCNT weakly adsorbed gas molecules and its electronic properties were also insensitive to gas molecules. By replacing a C atom with TM atoms, all doping can significantly enhance the adsorption energy of gas/SWCNT complexes and their adsorption ability was in the same order: NH_3 > PH_3 > AsH_3. A remarkable increase in adsorption energy and charge transfer of these systems was expected to induce significant changes in the electrical conductivity of the TM-doped SWCNTs. This work revealed that the sensitivity of SWCNT-based chemical gas adsorptions and sensors can be greatly improved by introducing an appropriate TM dopant. Accordingly, TM-doped SWCNTs are more suitable for gas molecule adsorptions and detections than the pristine SWCNT.

  4. The diffusivity of cesium, strontium, carbon and nickel in concrete and mixtures of sodium bentonite and crushed rock

    International Nuclear Information System (INIS)

    Muurinen, A.; Penttilae-Hiltunen, P.; Rantanen, J.

    1986-07-01

    The engineering barriers suggested to be used for the disposal of low and intermediate level wastes in Finland are concrete and crushed rock or mixtures of crushed rock and bentonite. In the repository the barriers are saturated by groundwater and radionuclides may be released by diffusion through the barries. For safety analysis, the mechanisms by which the nuclides migrate and corresponding parameters should be known. In this study diffusion measurements on different types of concrete and mixtures of sodium bentonite and crushed rock were carried out. Radioactive isotopes of cesium, strontium, carbon and nickel were used as tracers. The apparent diffusivities (Dsub(a)) were evaluated on the basis of the measurements. The apparent diffusivity of cesium in concretes was 10 -14 ...10 -15 m 2 /s. Strontium was mainly sorbed on cement where it diffuses slowly. Part of strontium propably penetrates in the rock ballast by diffusion. The diffusivities of carbon and nickel in the concrete was low. The upper limit was evaluated to be Dsub(a) -14 m 2 /s. The diffusivity of cesium in the mixtures of crushed rock and bentonite varies between 0.5x10 -12 and 7x10 -12 m 2 /s. Cesium was mainly sorbed on the rock. The diffusivity of strontium was 2x10 -11 ...2x10 -12 m 2 /s. Strontium was mainly sorbed on bentonite. The diffusion of the sorbed ions (surface diffusion) seems to be a additional migration mechanism in the case of cesium and strontium in the mixture of bentonite and crushed rock. The diffusivity of carbon in the mixtures of crushed rock and bentonite was 6x10 -11 ...4x10 -12 m 2 /s. No sorption was found in the case of carbon. The measured Dsub(a) of nickel in the mixtures of crushed rock and bentonite was 4x10 -14 ...2x10 -15 m 2 /s. The experimental arrangement was not, however, in the stationary state and the more correct values would propably be 10 -13 ...10 -14 m 2 /s. No surface diffusion was found in the case of nickel. (author)

  5. A comparative study on production of stable carbon nano tube dispersions using gum arabic and sodium dodecyl sulphate

    International Nuclear Information System (INIS)

    Rashmi, W.; Ismail, A.F.; Jameel, A.T.; Yusof, F.; Khalid, M.; Mubarak, N.M.

    2009-01-01

    Full text: Improvements on the stability of carbon nano tube (CNT)-water suspensions are necessary to enhance the performance of CNT nano fluids. CNTs are usually packed into crystalline ropes that form strong networks due to Van der Waals attraction. Aggregation of these CNTs is obstacle to most of the applications which diminished its special properties. Thus, this paper aims to produce stable CNT dispersion using Gum Arabic (GA) and Sodium dodecyl sulphate (SDS) as dispersants. The CNT concentration is varied from 0.01-0.1 wt% while the concentration of dispersants is varied from 1-12 wt%, respectively. This work gives detailed information on effect of CNT concentration, dispersant concentration and sonication time on stability of CNT dispersions. UV-Vis Spectrophotometer was used to measure the concentration of CNTs with respect to sedimentation time. CNT-GA suspensions were found to be more stable compared to CNT-SDS suspensions. The homogeneous suspension of CNT-GA is stable for several months. (author)

  6. The quantitative monitoring of mechanochemical reaction between solid L-tartaric acid and sodium carbonate monohydrate by terahertz spectroscopy

    Science.gov (United States)

    Liu, Xiaohong; Liu, Guifeng; Zhao, Hongwei; Zhang, Zengyang; Wei, Yongbo; Liu, Min; Wen, Wen; Zhou, Xingtai

    2011-11-01

    The solid-state reaction of chiral tartaric acid and alkali carbonate was studied by terahertz time-domain spectroscopy (THz-TDS). The sodium tartrate dihydrate was synthesized with high efficiency by mechanical grinding in the solid-state without waste that is particularly sustainable and environmentally benign. Distinct THz absorptions were observed for reactants and products. It indicates that THz spectroscopy is sensitive to different materials and crystal structures. The characteristic THz absorption peak at 1.09 THz of L (+)-Tartaric acid was selected for quantitative analysis. The reaction kinetics could be expressed by the Second-order equation and the Jander equation, which is consistent with a three-dimensional diffusion mechanism. The combination of multi-techniques including synchrotron radiation X-ray powder diffraction (SRXRPD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) was used to investigate the grinding process and presented supporting evidences. The results demonstrate that THz spectroscopy technique has great potential applications in process monitoring and analysis in pharmaceutical and chemical synthesis industry.

  7. Ultrafast atomic process in X-ray emission by using inner-shell ionization method for sodium and carbon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Moribayashi, Kengo; Sasaki, Akira; Tajima, Toshiki [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment

    1998-07-01

    An ultrafast inner-shell ionization process with X-ray emission stimulated by high-intensity short-pulse X-ray is studied. Carbon and sodium atoms are treated as target matter. It is shown that atomic processes of the target determine the necessary X-ray intensity for X-ray laser emission as well as the features of X-ray laser such as wavelength and duration time. The intensity also depends on the density of initial atoms. Furthermore, we show that as the intensity of X-ray source becomes high, the multi-inner-shell ionization predominates, leading to the formation of hollow atoms. As the density of hollow atoms is increased by the pumping X-ray power, the emission of X-rays is not only of significance for high brightness X-ray measurement but also is good for X-ray lasing. New classes of experiments of pump X-ray probe and X-ray laser are suggested. (author)

  8. pH sensing in aqueous solutions using a MnO2 thin film electrodeposited on a glassy carbon electrode

    International Nuclear Information System (INIS)

    Cherchour, N.; Deslouis, C.; Messaoudi, B.; Pailleret, A.

    2011-01-01

    An electrolysis technique at a constant potential was used to develop a highly reproducible and fast elaboration method of adherent manganese dioxide thin films on a glassy carbon electrode from aqueous solutions containing sulfuric acid and manganese sulfate. The resulting films were found to have a nanostructured character presumably due rather to birnessite (δ-MnO 2 ) than to γ-MnO 2 , as suggested by their Raman and XRD signatures. They lead to modified electrodes that present an obvious although complex pH dependent potentiometric response. This sensor indeed showed a single slope non-Nernstian linear behaviour over the 1.5-12 pH range for increasing pH direction ('trace'), whereas a Nernstian two slopes linear behaviour was observed for decreasing pH direction ('re-trace'). Preliminary EIS experiments carried out at a pH value of 1.8 seem to reveal a sensitivity mechanism based on proton insertion process at least at highly acidic pH values.

  9. pH sensing in aqueous solutions using a MnO{sub 2} thin film electrodeposited on a glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cherchour, N. [Laboratoire de Technologie des Materiaux et Genie des Procedes (LTMGP), Departement de Genie des Procedes, Universite A. Mira, Route de Targa Ouzemmour, 06000 Bejaia (Algeria); CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); Deslouis, C. [CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); Messaoudi, B. [Laboratoire de Technologie des Materiaux et Genie des Procedes (LTMGP), Departement de Genie des Procedes, Universite A. Mira, Route de Targa Ouzemmour, 06000 Bejaia (Algeria); Pailleret, A., E-mail: alain.pailleret@upmc.fr [CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France)

    2011-11-30

    An electrolysis technique at a constant potential was used to develop a highly reproducible and fast elaboration method of adherent manganese dioxide thin films on a glassy carbon electrode from aqueous solutions containing sulfuric acid and manganese sulfate. The resulting films were found to have a nanostructured character presumably due rather to birnessite ({delta}-MnO{sub 2}) than to {gamma}-MnO{sub 2}, as suggested by their Raman and XRD signatures. They lead to modified electrodes that present an obvious although complex pH dependent potentiometric response. This sensor indeed showed a single slope non-Nernstian linear behaviour over the 1.5-12 pH range for increasing pH direction ('trace'), whereas a Nernstian two slopes linear behaviour was observed for decreasing pH direction ('re-trace'). Preliminary EIS experiments carried out at a pH value of 1.8 seem to reveal a sensitivity mechanism based on proton insertion process at least at highly acidic pH values.

  10. Sodium fire protection

    International Nuclear Information System (INIS)

    Raju, C.; Kale, R.D.

    1979-01-01

    Results of experiments carried out with sodium fires to develop extinguishment techniques are presented. Characteristics, ignition temperature, heat evolution and other aspects of sodium fires are described. Out of the powders tested for extinguishment of 10 Kg sodium fires, sodium bi-carbonate based dry chemical powder has been found to be the best extinguisher followed by large sized vermiculite and then calcium carbonate powders distributed by spray nozzles. Powders, however, do not extinguish large fires effectively due to sodium-concrete reaction. To control large scale fires in a LMFBR, collection trays with protective cover have been found to cause oxygen starvation better than flooding with inert gas. This system has an added advantage in that there is no damage to the sodium facilities as has been in the case of powders which often contain chlorine compounds and cause stress corrosion cracking. (M.G.B.)

  11. Combined effect of glycation and sodium carbonate-bicarbonate buffer concentration on IgG binding, IgE binding and conformation of ovalbumin.

    Science.gov (United States)

    Ma, Xiao-juan; Gao, Jin-yan; Chen, Hong-bing

    2013-10-01

    Ovalbumin (OVA) is a major allergen in hen egg. During thermal processing, reducing sugars contained in the hen egg white might easily undergo glycation with OVA, but few studies have been conducted on its corresponding immunoreactivity changes. The aim of the present study was to assess changes of the antigenicity, potential allergenicity and conformation of OVA after glycation in a wet-thermal processing system under different concentrations of sodium carbonate-bicarbonate buffer. IgE binding of the glycated OVA was increased after glycation, and the higher the sodium carbonate-bicarbonate buffer concentration, the higher the IgE binding capacity. The increase in IgE binding of OVA corresponded well with the disruption of the disulfide bond, which exposed the epitopes initially buried. Antigenicity of the glycated OVA was increased, and the amount of the increase varied among samples treated under different buffer concentrations. Glycation increased the allergenic potential for OVA, with the amount of increase varying with different sodium carbonate-bicarbonate buffer concentrations. © 2013 Society of Chemical Industry.

  12. A wide range optical pH sensor for living cells using Au@Ag nanoparticles functionalized carbon nanotubes based on SERS signals.

    Science.gov (United States)

    Chen, Peng; Wang, Zhuyuan; Zong, Shenfei; Chen, Hui; Zhu, Dan; Zhong, Yuan; Cui, Yiping

    2014-10-01

    p-Aminothiophenol (pATP) functionalized multi-walled carbon nanotubes (MWCNTs) have been demonstrated as an efficient pH sensor for living cells. The proposed sensor employs gold/silver core-shell nanoparticles (Au@Ag NPs) functionalized MWCNTs hybrid structure as the surface-enhanced Raman scattering (SERS) substrate and pATP molecules as the SERS reporters, which possess a pH-dependent SERS performance. By using MWCNTs as the substrate to be in a state of aggregation, the pH sensing range could be extended to pH 3.0∼14.0, which is much wider than that using unaggregated Au@Ag NPs without MWCNTs. Furthermore, the pH-sensitive performance was well retained in living cells with a low cytotoxicity. The developed SERS-active MWCNTs-based nanocomposite is expected to be an efficient intracellular pH sensor for bio-applications.

  13. Synthesis of yellow fluorescent carbon dots and their application to the determination of chromium(III) with selectivity improved by pH tuning

    International Nuclear Information System (INIS)

    Chang, Melissa May Fung; Ginjom, Irine Runnie; Ng, Sing Muk; Ngu-Schwemlein, Maria

    2016-01-01

    Carbon dots with yellow fluorescence (y-CDs) were synthesized from sucrose by acid carbonization with phosphoric acid as the dehydrating agent. Optimal yield was obtained by heating sucrose in concentrated phosphoric acid to 85 °C for 30 min. The resulting y-CDs under the photo-excitation at 360 nm display an emission band peaking at 560 nm. The fluorescence is independent of pH values in the range from pH 4.0 to 11.4, and at ionic strengths of up to 4.7 M of potassium chloride. We also show that these y-CDs are viable fluorescent probes for the detection of chromium(III). At near neutral pH conditions, several metal ions quench the emission of the y-CDs, but under acidic conditions (pH 4), fluorescence is strongly affected by Cr(III) only. Quenching depends on the concentration of Cr(III) in the range up to 200 μM, and the limit of detection is 24.6 μM. (author)

  14. SnSe/carbon nanocomposite synthesized by high energy ball milling as an anode material for sodium-ion and lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Zhian; Zhao, Xingxing; Li, Jie

    2015-01-01

    Graphical abstract: A homogeneous nanocomposite of SnSe and carbon black was synthesised by high energy ball milling and empolyed as an anode material for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). The nanocomposite anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Highlights: • A homogeneous nanocomposite of SnSe and carbon black was fabricated by high energy ball milling. • SnSe and carbon black are homogeneously mixed at the nanoscale level. • The SnSe/C anode exhibits excellent electrochemical performances in both SIBs and LIBs. - Abstract: A homogeneous nanocomposite of SnSe and carbon black, denoted as SnSe/C nanocomposite, was fabricated by high energy ball milling and empolyed as a high performance anode material for both sodium-ion batteries and lithium-ion batteries. The X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy observations confirmed that SnSe in SnSe/C nanocomposite was homogeneously distributed within carbon black. The nanocomposite anode exhibited enhanced electrochemical performances including a high capacity, long cycling behavior and good rate performance in both sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). In SIBs, an initial capacitiy of 748.5 mAh g −1 was obtained and was maintained well on cycling (324.9 mAh g −1 at a high current density of 500 mA g −1 in the 200 th cycle) with 72.5% retention of second cycle capacity (447.7 mAh g −1 ). In LIBs, high initial capacities of approximately 1097.6 mAh g −1 was obtained, and this reduced to 633.1 mAh g −1 after 100 cycles at 500 mA g −1

  15. Influence of the alloying elements vanadium, chromium and carbon on the electrochemical behavior of uranium in media with a pH 13 or a pH acid

    International Nuclear Information System (INIS)

    Pommier, Gerard; Jouve, Gerard; Lacombe, Paul.

    1976-06-01

    The electrochemical properties of uranium alloys with low vanadium and chromium contents were studied in aqueous medium for different pH values of the solution (pH between 0 and 5 in H 2 SO 4 medium and pH=13 in NaOH medium). In acid medium, the study of the behavior of the two types of alloys carried out by the potentiokinetic method is described. The specific role of chromium concerning the anodic process is demonstrated and the influence of vanadium in specimens of same nominal vanadium contents but different carbon contents is revealed by the modification of the reduction overvoltage of water. In basic medium, the electrochemical study was supported by an optical method of determining the relative growth kinetics of the films in situ and continuously. At lower values of potential, the growth of an oxide film of UO 2 with linear growth kinetics is demonstrated; at higher values of potential a system of two layers is observed and its evolution is followed kinematically. The film initially formed is constituted of an oxide UO 3 2H 2 O, and its growth is linear, then a film of UO 2 develops underneath. A structural evolution of the superficial film is then observed, an evolution which leads to its cracking after breakdown. These phenomena were followed by electron microscopy using a technic of two stage replicas [fr

  16. Changes in EC , pH and in the concentrations of nitrate, ammonium, sodium and chlorine in the drainage solution of a crop of roses on substrates with drainage recycling

    Directory of Open Access Journals (Sweden)

    Mariela Rodríguez

    2012-08-01

    Full Text Available The rose cultivation system has been changing from soil to substrate on the Plateau of Bogota. The objective of this study was the monitoring of the EC, pH, and the levels of nitrate, ammonium, sodium and chlorine in a drainage solution in a crop of roses with substrates based on burnt rice husk and coconut fiber. The Charlotte rose variety grafted onto ‘Natal Briar’ was planted in a greenhouse located in one of the SENA facilities in Mosquera (Colombia; with a density of 6.5 plants/ m². For this experiment, a split plot design was used arranged in randomized blocks with a three-level recirculating system (0, 50 and 100% on the substrates 100% burnt rice husk; 65% burnt rice husk plus 35% coconut fiber; and 35% burnt rice husk plus 65% coconut fiber, repeated three times. The EC decreased from 2.7 to 1.3 mS cm-1 within weeks 2 and 5 which demonstrated an increase of mineral consumption by the plants. The pH levels dropped from 7.46 to 6.27 within weeks 3 to 8 and then increased to 7.39 within weeks 8 to 12. Nitrate concentrations showed a decreasing trend in recirculation treatments within weeks 2 to 12. A lower ammonium concentration was observed at week 4 in treatments with and without recirculation during the vegetative stage. The levels of sodium and chloride increased in treatments with a recirculation system, without signs of toxicity

  17. Continuing Assessment of the 5-Day Sodium Carbonate-Ammonium Nitrate Extraction Assay as an Indicator Test for Silicon Fertilizers.

    Science.gov (United States)

    Zellner, Wendy; Friedrich, Russell L; Kim, Sujin; Sturtz, Douglas; Frantz, Jonathan; Altland, James; Krause, Charles

    2015-01-01

    The 5-day sodium carbonate-ammonium nitrate extraction assay (5-day method) has been recognized by the American Association of Plant Food Control Officials as a validated test method to identify fertilizers or beneficial substances that provide plant-available silicon (Si). The test method used the molybdenum blue colorimetric assay to quantify percentage Si; however, laboratories may use inductively coupled plasma optical emission spectroscopy (ICP-OES) for elemental analysis. To examine the use of either colorimetric or ICP-OES methods for Si determination, the 5-day method was performed on the following Si-containing compounds; wollastonite, sand, biochar, and a basic oven furnace (BOF) slag. Grow-out studies using Zinnia elegans were also performed using varying rates of the wollastonite, biochar, and BOF slag. Our results show using the 5-day method, wollastonite had the highest extracted amounts of silicic acid (H4SiO4) at 4% followed by biochar (2%), BOF slag (1%), and sand (0%). Extraction values calculated using either the molybdenum blue colorimetric assay or ICP-OES for detection of the H4SiO4 had a significant correlation, supporting the application of either detection method for this type of analysis. However, when extracted values were compared to amounts of Si taken up by the plants, the 5-day method overestimated both wollastonite and biochar. While this method is a valid indicator test for determining a soluble Si source, other plant species and methods should be perused to potentially provide more quantitative analyses for plant-available Si content of all materials.

  18. Self-doped carbon architectures with heteroatoms containing nitrogen, oxygen and sulfur as high-performance anodes for lithium- and sodium-ion batteries

    International Nuclear Information System (INIS)

    Lu, Mingjie; Yu, Wenhua; Shi, Jing; Liu, Wei; Chen, Shougang; Wang, Xin; Wang, Huanlei

    2017-01-01

    Highlights: •Self-doped carbon architectures with nitrogen, oxygen, and sulfur are derived from Carrageen. •The obtained carbon materials exhibit excellent electrochemical property. •The strategy provides a one-step synthesis route to design advanced anodes for batteries. -- Abstract: Nitrogen, oxygen and sulfur tridoped porous carbons have been successfully synthesized from natural biomass algae-Carrageen by using a simultaneous carbonization and activation procedure. The doped carbons with sponge-like interconnected architecture, partially ordered graphitic structure, and abundant heteroatom doping perform outstanding features for electrochemical energy storage. When tested as lithium-ion battery anodes, a high reversible capacity of 839 mAh g −1 can be obtained at the current density of 0.1 A g −1 after 100 cycles, while a high capacity of 228 mAh g −1 can be maintained at 10 A g −1 . Tested against sodium, a high specific capacity of 227 can be delivered at 0.1 A g −1 after 100 cycles, while a high capacity of 109 mAh g −1 can be achieved at 10 A g −1 . These results turn out that the doped carbons would be potential anode materials for lithium- and sodium-ion batteries, which can be achieved by a one-step and large-scale synthesis route. Our observation indicates that heteroatom doping (especially sulfur) can significantly promote ion storage and reduce irreversible ion trapping to some extent. This work gives a general route for designing carbon nanostructures with heteroatom doping for efficient energy storage.

  19. Effects of the addition of nanoparticulate calcium carbonate on setting time, dimensional change, compressive strength, solubility and pH of MTA.

    Science.gov (United States)

    Bernardi, A; Bortoluzzi, E A; Felippe, W T; Felippe, M C S; Wan, W S; Teixeira, C S

    2017-01-01

    To evaluate nanoparticulate calcium carbonate (NPCC) using transmission electron microscopy and the effects of NPCC addition to MTA in regard to the setting time, dimensional change, compressive strength, solubility and pH. The experimental groups were G1 (MTA), G2 (MTA with 5% NPCC) and G3 (MTA with 10% NPCC). The tests followed ISO and ADA standards. The specimens in the dimensional change and compressive strength tests were measured immediately after setting, after 24 h and after 30 days. In the solubility test, rings filled with cement were weighed after setting and after 30 days. The pH was measured after 24 h and 30 days. The data were analysed with the ANOVA, Tukey's and Kruskal-Wallis tests (α = 5%). The setting time was reduced (P  G2 > G3). The solubility test revealed a difference amongst the groups when the specimens were hydrated: G2 > G1 > G3 and dehydrated: G3 > G2 > G1. The pH of the groups was similar at 24 h with higher values in each group after 30 days (P calcium carbonate had a cubic morphology with few impurities. The addition of nanoparticulate calcium carbonate to MTA accelerated the setting time, decreased compressive strength and, after 30 days, resulted in lower dimensional change (G2), higher solubility and a higher pH. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  20. Influence of Synthesis pH on Textural Properties of Carbon Xerogels as Supports for Pt/CXs Catalysts for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    C. Alegre

    2012-01-01

    Full Text Available Carbon xerogels (CXs have been prepared by polycondensation of resorcinol and formaldehyde. Two synthesis pHs were studied in order to evaluate its influence on the electrochemical behaviour of Pt catalysts supported on previous carbon xerogels, synthesized by conventional impregnation method. Catalysts were also synthesized over a commercial carbon black (Vulcan-XC-72R for comparison purposes. Characterization techniques included nitrogen physisorption, scanning electron microscopy, and X-ray diffraction. Catalysts electrochemical activity towards the oxidation of carbon monoxide and methanol was studied by cyclic voltammetry and chronoamperometry to establish the effect of the carbon support on the catalysts performance. Commercial Pt/C catalyst (E-TEK was analyzed for comparison purposes. It was observed that the more developed and mesopore-enriched porous structure of the carbon xerogel synthesized at a higher initial pH resulted in an optimal utilization of the active phase and in an enhanced and promising catalytic activity in the electrooxidation of methanol, in comparison with commercial catalysts.

  1. Degradation modes of austenitic and ferritic–martensitic stainless steels in He–CO–CO2 and liquid sodium environments of equivalent oxygen and carbon chemical potentials

    International Nuclear Information System (INIS)

    Gulsoy, G.; Was, G.S.; Pawel, S.J.; Busby, J.T.

    2013-01-01

    The objective of this work is to explore possible thermodynamic correlations between the degradation modes of austenitic and ferritic–martensitic alloys observed in high temperature He–CO–CO 2 environments with oxygen and carbon chemical potentials equivalent to that in a liquid sodium environment containing 2–5 molppm oxygen and 0.02–0.2 molppm carbon at temperatures 500–700 °C. Two He–CO–CO 2 environments (Pco/Pco 2 = 1320, Pco = 1980 molppm, and Pco/Pco 2 = 9, Pco = 13.5 molppm) were selected to test alloys NF616 and 316L at 700 and 850 °C. Upon exposure to He environments at 850 °C, 316L samples exhibited thick surface Cr 2 O 3 scales and substantial internal oxidation; however at 700 °C no significant internal oxidation was observed. NF616 samples exhibited relatively thinner surface Cr 2 O 3 scales compared to 316L samples at both temperatures. NF616 samples exposed to liquid sodium at 700 °C and He–Pco/Pco 2 = 9 at 850 °C showed decarburization. No surface oxide formation was observed on the sample exposed to the Na environment. Results obtained from He exposure experiments provide insight into what may occur during long exposure times in a sodium environment

  2. Degradation modes of austenitic and ferritic–martensitic stainless steels in He–CO–CO{sub 2} and liquid sodium environments of equivalent oxygen and carbon chemical potentials

    Energy Technology Data Exchange (ETDEWEB)

    Gulsoy, G., E-mail: gulsoy@umich.edu [Department of Materials Science and Engineering, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Was, G.S. [Department of Materials Science and Engineering, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Pawel, S.J.; Busby, J.T. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2013-10-15

    The objective of this work is to explore possible thermodynamic correlations between the degradation modes of austenitic and ferritic–martensitic alloys observed in high temperature He–CO–CO{sub 2} environments with oxygen and carbon chemical potentials equivalent to that in a liquid sodium environment containing 2–5 molppm oxygen and 0.02–0.2 molppm carbon at temperatures 500–700 °C. Two He–CO–CO{sub 2} environments (Pco/Pco{sub 2} = 1320, Pco = 1980 molppm, and Pco/Pco{sub 2} = 9, Pco = 13.5 molppm) were selected to test alloys NF616 and 316L at 700 and 850 °C. Upon exposure to He environments at 850 °C, 316L samples exhibited thick surface Cr{sub 2}O{sub 3} scales and substantial internal oxidation; however at 700 °C no significant internal oxidation was observed. NF616 samples exhibited relatively thinner surface Cr{sub 2}O{sub 3} scales compared to 316L samples at both temperatures. NF616 samples exposed to liquid sodium at 700 °C and He–Pco/Pco{sub 2} = 9 at 850 °C showed decarburization. No surface oxide formation was observed on the sample exposed to the Na environment. Results obtained from He exposure experiments provide insight into what may occur during long exposure times in a sodium environment.

  3. Geochemical Impacts to Groundwater from Geologic Carbon Sequestration: Controls on pH and Inorganic Carbon Concentrations from Reaction Path and Kinetic Modeling

    Science.gov (United States)

    Geologic carbon sequestration has the potential to cause long-term reductions in global emissions of carbon dioxide to the atmosphere. Safe and effective application of carbon sequestration technology requires an understanding of the potential risks to the quality of underground...

  4. Carbon Dioxide Nucleation as a Novel Cleaning Method for Sodium Alginate Fouling Removal from Reverse Osmosis Membranes desalination

    KAUST Repository

    Alnajjar, Heba

    2017-05-01

    The use of Reverse osmosis (RO) membranes have been significantly increasing in water desalination, and the main operational obstacle in RO desalination plants is membrane fouling. Among other solutes, dissolved biopolymers, such as polysaccharides can lead to severe membrane fouling especially with the addition of calcium ions because of the complexation formation between the surface of membrane and foulants materials. However, this complexation can also take place in the feed bulk, resulting in foulants aggregates formation. Although there are some physical techniques that can maintain the membrane performance without reducing its lifetime, only chemical cleanings are still commonly used in RO plants. In this study, a novel cleaning method is proposed to restore the membrane performance by removing the deposited foulants without reducing the membrane lifetime. The cleaning method is based on using water saturated with dissolved CO2 gas, and its principle is based on producing spontaneous CO2 bubbles due to local pressure difference leading to nucleation of bubbles throughout the membrane surface, especially at nucleation sites, which improve the cleaning efficiency. Alginic acid sodium salt was used as a model of polysaccharides foulants in presence of different concentrations of NaCl and calcium ions aiming to enhance membrane fouling, and then CO2 cleaning solution efficiency, in terms flux recovery (FR), was tested under different operating conditions and compared to other cleaning methods. Average FR of 20%±3, 25%±3 and 80%±3 for MilliQ water, a cleaning solution at pH4, and CO2 solution at 6 bar, 0.17 m/s, and 23 ̊C ±0.2 for 6 minutes were obtained, respectively. The efficiency of this novel cleaning method was also compared to direct osmosis overnight, and the average flux was comparable (about 60%±3), though that the cleaning time was significantly different. Various calcium concentrations (0-10 mM) were added in the alginate solution to study the

  5. Micro-syntheses for the use of carbon 13 or carbon 14. Micro-preparations of methyl alcohol, methyl iodide, and sodium acetate labeled in the methyl group; Microsyntheses pour l'emploi de carbone 13 ou de carbone 14. Micropreparations d'alcool methylique, d'iodure de methyle et d'acetate de sodium marque sur le groupement methyle

    Energy Technology Data Exchange (ETDEWEB)

    Baret, C; Pichat, L

    1951-11-01

    Apparatus and technique are described in detail for (1) reduction of CO{sub 2} to CH{sub 3}OH with LiAlH{sub 4}, (2) conversion of the methanol to CH{sub 3}I by HI, (3) formation of the Mg Grignard reagent, and (4) addition of inactive CO{sub 2} to form CH{sub 3}COOH. All these operations have been carried out on 0.005 moles. Methyl-labeled Na acetate has been prepared in 67% yield based on the Ba{sup 14}CO{sub 3} used as starting material. (author) [French] Description detaillee d'une technique deja connue pour la reduction du gaz carbonique en alcool methylique par LiAlH{sub 4}. Conversion du methanol en iodure de methyle. Ce dernier transforme en reactif de Grigard, et carbonate, fournit de l'acide acetique. Toutes ces operations on ete effectuees sur 5 x 10{sup -3} moles. La methode a ete appliquee a la synthese d'acetate de sodium marque par le groupement methyle par {sup 14}C avec un rendement global de 67% base sur le carbonate de baryum radioactif mis en oeuvre. (auteurs)

  6. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.

    Science.gov (United States)

    Uchimiya, Minori; Bannon, Desmond I

    2013-08-14

    Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 °C (CH350) and 700 °C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.

  7. One-step synthesis of nitrogen-doped carbon nanodots for ratiometric pH sensing by femtosecond laser ablation method

    International Nuclear Information System (INIS)

    Xu, Huanhuan; Yan, Lihe; Nguyen, Vanthan; Yu, Yang; Xu, Yanmin

    2017-01-01

    Highlights: • Nitrogen-containing carbon nanodots (CDs) are synthesize using pulsed laser ablation in liquid. • The CDs show a strong fluorescence consisting of a dual-band luminescence peak. • The as prepared CDs can offer a ratiometric sensing platform for the detection the pH values. - Abstract: Nitrogen-doped carbon nanodots (CDs) are synthesized by one-step femtosecond laser ablation of graphite powder in aminotoluene at room temperature. The as-prepared CDs have the average diameter of 2.87 nm and possess an excitation-independent emission covering nearly the whole visible light region at a single excitation wavelength. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicate that there are a huge number of multiple oxygen groups and amine groups on the surface of the CDs. As their different fluorescence peaks originated from different emission surface groups on the nanodots show different pH dependence, these CDs can be used for ratiometric pH sensing.

  8. One-step synthesis of nitrogen-doped carbon nanodots for ratiometric pH sensing by femtosecond laser ablation method

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Huanhuan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Yan, Lihe, E-mail: liheyan@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Nguyen, Vanthan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Le Quy Don Technical University, Hanoi 122314 (Viet Nam); Yu, Yang; Xu, Yanmin [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

    2017-08-31

    Highlights: • Nitrogen-containing carbon nanodots (CDs) are synthesize using pulsed laser ablation in liquid. • The CDs show a strong fluorescence consisting of a dual-band luminescence peak. • The as prepared CDs can offer a ratiometric sensing platform for the detection the pH values. - Abstract: Nitrogen-doped carbon nanodots (CDs) are synthesized by one-step femtosecond laser ablation of graphite powder in aminotoluene at room temperature. The as-prepared CDs have the average diameter of 2.87 nm and possess an excitation-independent emission covering nearly the whole visible light region at a single excitation wavelength. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicate that there are a huge number of multiple oxygen groups and amine groups on the surface of the CDs. As their different fluorescence peaks originated from different emission surface groups on the nanodots show different pH dependence, these CDs can be used for ratiometric pH sensing.

  9. In situ Microscopic Observation of Sodium Deposition/Dissolution on Sodium Electrode

    OpenAIRE

    Yuhki Yui; Masahiko Hayashi; Jiro Nakamura

    2016-01-01

    Electrochemical sodium deposition/dissolution behaviors in propylene carbonate-based electrolyte solution were observed by means of in situ light microscopy. First, granular sodium was deposited at pits in a sodium electrode in the cathodic process. Then, the sodium particles grew linearly from the electrode surface, becoming needle-like in shape. In the subsequent anodic process, the sodium dissolved near the base of the needles on the sodium electrode and the so-called ?dead sodium? broke a...

  10. Sodium carbonate revisted

    Czech Academy of Sciences Publication Activity Database

    Dušek, Michal; Chapuis, G.; Meyer, M.; Petříček, Václav

    2003-01-01

    Roč. 59, - (2003), s. 337-352 ISSN 0108-7681 R&D Projects: GA ČR GA202/02/0916 Institutional research plan: CEZ:AV0Z1010914 Keywords : structure determination * modulated crystal of Na 2 CO 3 * incommensurate and commensurate phases Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.643, year: 2003

  11. Emission switching in carbon dots coated CdTe quantum dots driving by pH dependent hetero-interactions

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Xiao; Wang, Hao; Yi, Qinghua; Wang, Yun; Cong, Shan; Zhao, Jie; Sun, Yinghui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn, E-mail: jiexiong@uestc.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Qian, Zhicheng [School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Huang, Jianwen; Xiong, Jie, E-mail: zouguifu@suda.edu.cn, E-mail: jiexiong@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Luo, Hongmei [Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States)

    2015-11-16

    Due to the different emission mechanism between fluorescent carbon dots and semiconductor quantum dots (QDs), it is of interest to explore the potential emission in hetero-structured carbon dots/semiconducting QDs. Herein, we design carbon dots coated CdTe QDs (CDQDs) and investigate their inherent emission. We demonstrate switchable emission for the hetero-interactions of the CDQDs. Optical analyses indicate electron transfer between the carbon dots and the CdTe QDs. A heterojunction electron process is proposed as the driving mechanism based on N atom protonation of the carbon dots. This work advances our understanding of the interaction mechanism of the heterostructured CDQDs and benefits the future development of optoelectronic nanodevices with new functionalities.

  12. Ultra-bright red-emitting photostable perylene bisimide dyes: new indicators for ratiometric sensing of high pH or carbon dioxide.

    Science.gov (United States)

    Pfeifer, David; Klimant, Ingo; Borisov, Sergey M

    2018-05-08

    New pH sensitive perylene bisimide indicator dyes were synthesised and used for fabrication of optical sensors. The highly photostable dyes show absorption/emission bands in the red/near-infrared (NIR) region of the electromagnetic spectrum, high molar absorption coefficients (up to 100 000 M-1 cm-1) and fluorescence quantum yields close to unity. The absorption and emission spectra show strong bathochromic shift upon deprotonation of imidazole nitrogen which makes the dyes promising as ratiometric fluorescent indicators. Physical entrapment of the indicators into polyurethane hydrogel enables pH determination in alkaline pH. It is also shown that plastic carbon dioxide solid state sensor can be manufactured via immobilization of the pH indicator in a hydrophilic polymer, along with a quaternary ammonium base. The influence of plasticizer, different lipophilic bases and humidity on the sensitivity of the sensor material were systematically investigated. The disubstituted perylene, particularly, features two deprotonation equilibria enabling sensing over a very broad range from 0.5 to 1000 hPa pCO2. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. pH neutralization of the by-product sludge waste water generated from waste concrete recycling process using the carbon mineralization

    Science.gov (United States)

    Ji, Sangwoo; Shin, Hee-young; Bang, Jun Hwan; Ahn, Ji-Whan

    2017-04-01

    About 44 Mt/year of waste concrete is generated in South Korea. More than 95% of this waste concrete is recycled. In the process of regenerating and recycling pulmonary concrete, sludge mixed with fine powder generated during repeated pulverization process and water used for washing the surface and water used for impurity separation occurs. In this way, the solid matter contained in the sludge as a by-product is about 40% of the waste concrete that was input. Due to the cement component embedded in the concrete, the sludge supernatant is very strong alkaline (pH about 12). And it is necessary to neutralization for comply with environmental standards. In this study, carbon mineralization method was applied as a method to neutralize the pH of highly alkaline waste water to under pH 8.5, which is the water quality standard of discharged water. CO2 gas (purity 99%, flow rate 10ml/min.) was injected and reacted with the waste water (Ca concentration about 750mg/L) from which solid matter was removed. As a result of the experiment, the pH converged to about 6.5 within 50 minutes of reaction. The precipitate showed high whiteness. XRD and SEM analysis showed that it was high purity CaCO3. For the application to industry, it is needed further study using lower concentration CO2 gas (about 14%) which generated from power plant.

  14. Total aerobic destruction of azo contaminants with nanoscale zero-valent copper at neutral pH: promotion effect of in-situ generated carbon center radicals.

    Science.gov (United States)

    Dong, Guohui; Ai, Zhihui; Zhang, Lizhi

    2014-12-01

    In this study, nanoscale zero-valent copper (nZVC) was synthesized with a facile solvothermal method and used for the aerobic removal of azo contaminants at neutral pH for the first time. We found that both Cu(I) and OH generated during the nZVC induced molecular oxygen activation process accounted for the rapid total destruction of azo contaminants in the nZVC/Air system, where nZVC could activate molecular oxygen to produce H2O2, and also release Cu(I) to break the -NN- bond of azo contaminants via the sandmeyer reaction for the generation of carbon center radicals. The in-situ generated carbon center radicals would then react with OH produced by the Cu(I) catalyzed decomposition of H2O2, resulting in the generation of low molecular weight organic acids and their subsequent mineralization. The indispensible role of Cu(I) catalyzed sandmeyer reaction and the promotion effect of in-situ generated carbon center radicals on the rapid total destruction of azo contaminants in the nZVC/Air system were confirmed by gas chromatography-mass spectrometry analysis. This study can deepen our understanding on the degradation of organic pollutant with molecular oxygen activated by zero valent metal, and also provide a new method to remove azo contaminants at neutral pH. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Carboxylated, Fe-filled multiwalled carbon nanotubes as versatile catalysts for O2 reduction and H2 evolution reactions at physiological pH.

    Science.gov (United States)

    Bracamonte, M Victoria; Melchionna, Michele; Stopin, Antoine; Giulani, Angela; Tavagnacco, Claudio; Garcia, Yann; Fornasiero, Paolo; Bonifazi, Davide; Prato, Maurizio

    2015-09-01

    The development of new electrocatalysts for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at physiological pH is critical for several fields, including fuel cells and biological applications. Herein, the assembly of an electrode based on carboxyl-functionalised hydrophilic multiwalled carbon nanotubes (MWCNTs) filled with Fe phases and their excellent performance as electrocatalysts for ORR and HER at physiological pH are reported. The encapsulated Fe dramatically enhances the catalytic activity, and the graphitic shells play a double role of efficiently mediating the electron transfer to O2 and H2 O reactants and providing a cocoon that prevents uncontrolled Fe oxidation or leaching. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Functional significance of tree species diversity and species identity on soil organic carbon, C/N ratio and pH in major European forest types

    DEFF Research Database (Denmark)

    Dawud, Seid Muhie

    Forests provide different ecosystem functions and services including soil carbon sequestration and nutrient supply to maintain growth and productivity. This PhD thesis explored tree species diversity and tree species identity (conifer proportion of basal area) effects on soil C stock and nutrient...... 8 and 12 years old common garden stands established in two contrasting bioclimatic regions. In all the studied contexts, tree species identity (confers versus broadleaves) was stronger than diversity in consistently driving variability of the examined soil properties and root characteristics......, particularly in topsoil layers. Diversity did not affect fine root characteristics of the young forests and effects on soil properties were different under the investigated contexts. Across the different European sites, diversity had no effect on C/N ratio and pH but under comparable environmental conditions...

  17. Long-term stabilization of crop residues and soil organic carbon affected by residue quality and initial soil pH.

    Science.gov (United States)

    Wang, Xiaojuan; Butterly, Clayton R; Baldock, Jeff A; Tang, Caixian

    2017-06-01

    Residues differing in quality and carbon (C) chemistry are presumed to contribute differently to soil pH change and long-term soil organic carbon (SOC) pools. This study examined the liming effect of different crop residues (canola, chickpea and wheat) down the soil profile (0-30cm) in two sandy soils differing in initial pH as well as the long-term stability of SOC at the amended layer (0-10cm) using mid-infrared (MIR) and solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy. A field column experiment was conducted for 48months. Chickpea- and canola-residue amendments increased soil pH at 0-10cm in the Podzol by up to 0.47 and 0.36units, and in the Cambisol by 0.31 and 0.18units, respectively, at 48months when compared with the non-residue-amended control. The decomposition of crop residues was greatly retarded in the Podzol with lower initial soil pH during the first 9months. The MIR-predicted particulate organic C (POC) acted as the major C sink for residue-derived C in the Podzol. In contrast, depletion of POC and recovery of residue C in MIR-predicted humic organic C (HOC) were detected in the Cambisol within 3months. Residue types showed little impact on total SOC and its chemical composition in the Cambisol at 48months, in contrast to the Podzol. The final HOC and resistant organic C (ROC) pools in the Podzol amended with canola and chickpea residues were about 25% lower than the control. This apparent priming effect might be related to the greater liming effect of these two residues in the Podzol. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate).

    Science.gov (United States)

    Mukherjee, Soumalya; Ray, Mitali; Ray, Sajal

    2016-09-01

    Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. A new slurry pH model accounting for effects of ammonia and carbon dioxide volatilization on solution speciation

    DEFF Research Database (Denmark)

    Petersen, V.; Markfoged, R.; Hafner, S. D.

    2014-01-01

    a reduced variable that combines time and location and an analytical approach to solving the resulting system of equations using Mathematica. To evaluate the model, we made measurements of pH at a resolution of 0.1 mm in the top 30 mm of an ammonium bicarbonate solution. These measurements show the creation...

  20. Photon mass energy absorption coefficients from 0.4 MeV to 10 MeV for silicon, carbon, copper and sodium iodide

    International Nuclear Information System (INIS)

    Oz, H.; Gurler, O.; Gultekin, A.; Yalcin, S.; Gundogdu, O.

    2006-01-01

    The absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy absorption coefficients for gamma rays with an incident energy range between 0.4 MeV and 10 MeV in silicon, carbon, copper and sodium iodide. The mass energy absorption coefficients for gamma rays were calculated, and the results obtained were compared with the values reported in the literature.

  1. Photon mass energy absorption coefficients from 0.4 MeV to 10 MeV for silicon, carbon, copper and sodium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Oz, H.; Gurler, O.; Gultekin, A. [Uludag University, Bursa (Turkmenistan); Yalcin, S. [Kastamonu University, Kastamonu (Turkmenistan); Gundogdu, O. [University of Surrey, Guildford (United Kingdom)

    2006-07-15

    The absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy absorption coefficients for gamma rays with an incident energy range between 0.4 MeV and 10 MeV in silicon, carbon, copper and sodium iodide. The mass energy absorption coefficients for gamma rays were calculated, and the results obtained were compared with the values reported in the literature.

  2. Integrated combined effects of temperature, pH and sodium chloride concentration on biofilm formation by Salmonella enterica ser. Enteritidis and Typhimurium under low nutrient food-related conditions.

    Science.gov (United States)

    Iliadis, Ioannis; Daskalopoulou, Aikaterini; Simões, Manuel; Giaouris, Efstathios

    2018-05-01

    Salmonella enterica is a major foodborne bacterial pathogen. This forms biofilms on surfaces and persists, depending on the strain and the environment. The integrative interaction of temperature (T; 13-39 °C), pH (5-8) and sodium chloride (NaCl) concentration (0.5-8.5%) on biofilm formation by two S. enterica strains (ser. Enteritidis and Typhimurium) was here evaluated under low nutrient conditions. This was achieved using response surface methodology to model the combined effect of each factor on the response, through mathematical quadratic fitting of the outcomes of a sequence of designed experiments. These last were executed by incubating stainless steel coupons carrying sessile bacteria, for 24 h, in 1:10 diluted tryptone soya broth, under 15 different combinations of three independent factors (T, pH and NaCl). For each strain, a second order polynomial model, describing the relationship between biofilm formation (log CFU/cm 2 ) and the factors (T, pH and NaCl), was developed using least square regression analysis. Both derived models predicted the combined influences of these factors on biofilm formation, with agreement between predictions and experimental observations (R 2  ≥ 0.96, P ≤ 0.0001). For both strains, the increase of NaCl content restricted their sessile growth, while under low salinity conditions (NaCl formation was favored as pH increased, regardless of T. Interestingly, under low salt content, and depending on the strain, biofilm formation was either favored or hindered by increasing T. Thus, 34.5 and 13 °C were the T predicted to maximize biofilm formation by strains Enteritidis and Typhimurium, respectively, something which was also experimentally verified. To sum, these models can predict the interactive influences of crucial food-related factors on biofilm growth of a significant foodborne pathogen towards the efforts to limit its persistence in food industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Pasteurization of fruit juices of different pH values by combined high hydrostatic pressure and carbon dioxide.

    Science.gov (United States)

    Li, Wang; Pan, Jian; Xie, Huiming; Yang, Yi; Zhou, Dianfei; Zhu, Zhaona

    2012-10-01

    The inactivation of the selected vegetative bacteria Escherichia coli, Listeria innocua, and Lactobacillus plantarum by high hydrostatic pressure (HHP) in physiological saline (PS) and in four fruit juices with pHs ranging from 3.4 to 6.3, with or without dissolved CO(2), was investigated. The inactivation effect of HHP on the bacteria was greatly enhanced by dissolved CO(2). Effective inactivation (>7 log) was achieved at 250 MPa for E. coli and 350 MPa for L. innocua and L. plantarum in the presence of 0.2 M CO(2) at room temperature for 15 min in PS, with additional inactivation of more than 4 log for all three bacteria species compared with the results with HHP treatment alone. The combined inactivation by HHP and CO(2) in tomato juice of pH 4.2 and carrot juice of pH 6.3 showed minor differences compared with that in PS. By comparison, the combined effect in orange juice of pH 3.8 was considerably promoted, while the HHP inactivation was enhanced only to a limited extent. In another orange juice with a pH of 3.4, all three strains lost their pressure resistance. HHP alone completely inactivated E. coli at relatively mild pressures of 200 MPa and L. innocua and L. plantarum at 300 MPa. Observations of the survival of the bacteria in treated juices also showed that the combined treatment caused more sublethal injury, which increased further inactivation at a relatively mild pH of 4.2 during storage. The results indicated that the combined treatment of HHP with dissolved CO(2) may provide an effective method for the preservation of low- or medium-acid fruit and vegetable juices at relatively low pressures. HHP alone inactivated bacteria effectively in high-acid fruit juice.

  4. Enhanced cyclic stability of SnS microplates with conformal carbon coating derived from ethanol vapor deposition for sodium-ion batteries

    Science.gov (United States)

    Li, Xiang; Liu, Jiangwen; Ouyang, Liuzhang; Yuan, Bin; Yang, Lichun; Zhu, Min

    2018-04-01

    Carbon coated SnS microplates (SnS@C MPs) were prepared via a facile chemical vapor deposition method using SnS2 nanoflakes as precursor and ethanol vapor as carbon source. The carbon coating restrains the growth of SnS during the heat treatment. Furthermore, it improves the electronic conductivity as well as accommodates volume variations of SnS during the sodiation and desodiation processes. Therefore, the rate capability and cycle performance of the SnS@C MPs as anode materials for sodium-ion batteries are remarkably enhanced compared with the bare SnS and the SnS2 precursor. At current densities of 0.1, 0.2, 0.5, 1 and 2 A g-1, the optimized SnS@C MPs exhibit stable capacities of 602.9, 532.1, 512.2, 465.9 and 427.2 mAh g-1, respectively. At 1 A g-1, they show a reversible capacity of 528.8 mAh g-1 in the first cycle, and maintain 444.7 mAh g-1 after 50 cycles, with capacity retention of 84.1%. The carbon coating through chemical vapor deposition using ethanol vapor as carbon sources is green, simple and cost-effective, which shows great promise to improve the reversible Na+ storage of electrode materials.

  5. Mechanistic deductions from kinetic isotope effects and pH studies of pyridoxal phosphate dependent carbon-carbon lyases: Erwinia herbicola and Citrobacter freundii tyrosine phenol-lyase

    International Nuclear Information System (INIS)

    Kiick, D.M.; Phillips, R.S.

    1988-01-01

    The pH dependence of the kinetic parameters and primary deuterium isotope effects have been determined for tyrosine phenol-lyase from both Erwinia herbicola and Citrobacter freundii. The primary deuterium isotope effects indicate that proton abstraction from the 2-position of the substrate is partially rate-limiting for both enzymes. The C. freundii enzyme primary deuterium isotope effects [DV = 3.5 and D(V/Ktyr) = 2.5] are pH independent, indicating that tyrosine is not sticky (i.e., does not dissociate slower than it reacts to give products). Since Vmax for both tyrosine and the alternate substrate S-methyl-L-cysteine is also pH independent, substrate binds only to the correctly protonated form of the enzyme. For the E. herbicola enzyme, both Vmax and V/K for tyrosine or S-methyl-L-cysteine are pH dependent, as well as both DV and D(V/Ktyr). Thus, while both the protonated and unprotonated enzyme can bind substrate, and may be interconverted directly, only the unprotonated Michaelis complex is catalytically competent. At pH 9.5, DV = 2.5 and D(V/Ktyr) = 1.5. However, at pH 6.4 the isotope effect on both parameters is equal to 4.1. From these data, the forward commitment factor (cf = 5.2) and catalytic ratio (cvf = 1.1) for tyrosine and S-methyl-L-cysteine (cf = 2.2, cvf = 24) are calculated. Also, the Michaelis complex partition ratio (cf/cvf) for substrate and products is calculated to be 4.7 for tyrosine and 0.1 for S-methyl-L-cysteine

  6. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to carbonate and bicarbonate salts of sodium and potassium and maintenance of normal bone (ID 331, 1402) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to carbonate and bicarbonate salts of sodium and potassium and maintenance of normal bone. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member...... States or directly from stakeholders. The food constituents that are the subject of the health claim are carbonate and bicarbonate salts of sodium and potassium. The Panel considers that carbonate and bicarbonate salts of sodium and potassium are sufficiently characterised. The claimed effects are “acid...... the dietary intake of carbonate or bicarbonate salts of sodium or potassium and maintenance of normal bone....

  7. Simultaneous determination of copper, cobalt, and mercury ions in water samples by solid-phase extraction using carbon nanotube sponges as adsorbent after chelating with sodium diethyldithiocarbamate prior to high performance liquid chromatography.

    Science.gov (United States)

    Wang, Lei; Zhou, Jia-Bin; Wang, Xia; Wang, Zhen-Hua; Zhao, Ru-Song

    2016-06-01

    Recently, a sponge-like material called carbon nanotube sponges (CNT sponges) has drawn considerable attention because it can remove large-area oil, nanoparticles, and organic dyes from water. In this paper, the feasibility of CNT sponges as a novel solid-phase extraction (SPE) adsorbent for the enrichment and determination of heavy metal ions (Co(2+), Cu(2+), and Hg(2+)) was investigated for the first time. Sodium diethyldithiocarbamate (DDTC) was used as the chelating agent and high performance liquid chromatography (HPLC) for the final analysis. Important factors which may influence extraction efficiency of SPE were optimized, such as the kind and volume of eluent, volume of DDTC, sample pH, flow rate, etc. Under the optimized conditions, wide range of linearity (0.5-400 μg L(-1)), low limits of detection (0.089~0.690 μg L(-1); 0.018~0.138 μg), and good repeatability (1.27~3.60 %, n = 5) were obtained. The developed method was applied for the analysis of the three metal ions in real water samples, and satisfactory results were achieved. All of these findings demonstrated that CNT sponges will be a good choice for the enrichment and determination of target ions at trace levels in the future.

  8. Influence of carbon source, pH, and temperature on the polygalacturonase activity of Kluyveromyces marxianus CCMB 322

    Directory of Open Access Journals (Sweden)

    Rodrigo de Queiroz Oliveira

    2012-09-01

    Full Text Available Microbial pectinolytic enzymes are known to play a commercially important role in a number of industrial processes. Two kinds of yeast can be discerned regarding the production of enzymes. One group includes those which can produce enzymes in the absence of an inducer, and the other group comprises the yeasts that produce enzymes in the presence of an inducer. The objective of this study was to investigate the influence of pectic substances, glucose, pH, and temperature on the polygalacturonase activity by Kluyveromyces marxianus CCMB 322. The yeast was grown in a fermentation broth containing different concentrations of glucose and pectic substances. The polygalacturonase activity was determined by the DNS method, and the pH and temperature were optimized using a central composite experimental design. The polygalacturonase secreted by K. marxianus CCMB 322 was partially constitutive showing optimum pH and temperature of 7.36 and 70 °C, respectively, and maintained approximately 93% of its original activity for 50 minutes at 50 °C. Thermal stability of the polygalacturonase enzyme was studied at different temperatures (50, 60, 70, and 80 °C and different incubation times (0, 10, 20, 30, 40, and 50 minutes. This study showed that glucose can influence the regulation of the synthesis of polygalacturonase.

  9. A potential explanation for the effect of carbon source on the ...

    African Journals Online (AJOL)

    This paper proposes a new theory to account for the effect of carbon source on the characteristics of acetate-fed and glucose-fed aerobic granules. It is well known that reactor pH can vary in response to the oxidation of glucose or sodium acetate. As such, the effects associated with the carbon sources may be explained by ...

  10. Effect of Strength and Microstructure on Stress Corrosion Cracking Behavior and Mechanism of X80 Pipeline Steel in High pH Carbonate/Bicarbonate Solution

    Science.gov (United States)

    Zhu, Min; Du, Cuiwei; Li, Xiaogang; Liu, Zhiyong; Wang, Shengrong; Zhao, Tianliang; Jia, Jinghuan

    2014-04-01

    The stress corrosion cracking (SCC) behaviors and mechanisms of X80 pipeline steels with different strength and microstructure in high pH carbonate/bicarbonate solution were investigated by slow strain rate testing and electrochemical test. The results showed that the cracking mode of low strength X80 steel composed of bulky polygonal ferrite and granular bainite in high pH solution was intergranular (IGSCC), and the SCC mechanism was anodic dissolution (AD). While the mixed cracking mode of high strength X80 steel consisted of fine acicular ferrite and granular bainite was intergranular (IGSCC) in the early stage, and transgranular (TGSCC) in the later stage. The decrease of pH value of crack tip was probably the key reason for the occurrence of TGSCC. The SCC mechanism may be a mixed mode of AD and hydrogen embrittlement (HE), and the HE mechanism may play a significant role in the deep crack propagation at the later stage. The cracking modes and SCC mechanisms of the two X80 steels were associated with its microstructure and strength.

  11. High-sensitivity pH sensor using separative extended-gate field-effect transistors with single-walled carbon-nanotube networks

    Science.gov (United States)

    Pyo, Ju-Young; Cho, Won-Ju

    2018-04-01

    We fabricate high-sensitivity pH sensors using single-walled carbon-nanotube (SWCNT) network thin-film transistors (TFTs). The sensing and transducer parts of the pH sensor are composed of separative extended-sensing gates (ESGs) with SnO2 ion-sensitive membranes and double-gate structure TFTs with thin SWCNT network channels of ∼1 nm and AlO x top-gate insulators formed by the solution-deposition method. To prevent thermal process-induced damages on the SWCNT channel layer due to the post-deposition annealing process and improve the electrical characteristics of the SWCNT-TFTs, microwave irradiation is applied at low temperatures. As a result, a pH sensitivity of 7.6 V/pH, far beyond the Nernst limit, is obtained owing to the capacitive coupling effect between the top- and bottom-gate insulators of the SWCNT-TFTs. Therefore, double-gate structure SWCNT-TFTs with separated ESGs are expected to be highly beneficial for high-sensitivity disposable biosensor applications.

  12. Is Tree Species Diversity or Species Identity the More Important Driver of Soil Carbon Stocks, C/N Ratio, and pH?

    DEFF Research Database (Denmark)

    Dawud, Seid Muhie; Raulund-Rasmussen, Karsten; Domisch, Timo

    2016-01-01

    We explored tree species diversity effects on soil C stock, C/N ratio, and pH as compared with effects of tree species identity. We sampled forest floors and mineral soil (0–40 cm) in a diversity gradient of 1–5 tree species composed of conifers and broadleaves in Białowieża Forest, Poland...... mechanism for higher root carbon input and in turn a deeper distribution of C in diverse forests. Diversity and identity affected soil pH in topsoil with positive and negative impacts, respectively. More diverse forests would lead to higher soil nutrient status as reflected by higher topsoil p......H, but there was a slight negative effect on N status as indicated by higher C/N ratios in the deeper layers. We conclude that tree species diversity increases soil C stocks and nutrient status to some extent, but tree species identity is a stronger driver of the studied soil properties, particularly in the topsoil....

  13. N/S Co-Doped 3 D Porous Carbon Nanosheet Networks Enhancing Anode Performance of Sodium-Ion Batteries.

    Science.gov (United States)

    Zou, Lei; Lai, Yanqing; Hu, Hongxing; Wang, Mengran; Zhang, Kai; Zhang, Peng; Fang, Jing; Li, Jie

    2017-10-12

    A facile and scalable method is realized for the in situ synthesis of N/S co-doped 3 D porous carbon nanosheet networks (NSPCNNs) as anode materials for sodium-ion batteries. During the synthesis, NaCl is used as a template to prepare porous carbon nanosheet networks. In the resultant architecture, the unique 3 D porous architecture ensures a large specific surface area and fast diffusion paths of both electrons and ions. In addition, the import of N/S produces abundant defects, increased interlayer spacings, more active sites, and high electronic conductivity. The obtained products deliver a high specific capacity and excellent long-term cycling performance, specifically, a capacity of 336.2 mA h g -1 at 0.05 A g -1 , remaining as large as 214.9 mA h g -1 after 2000 charge/discharge cycles at 0.5 A g -1 . This material has great prospects for future applications of scalable, low-cost, and environmentally friendly sodium-ion batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Synthesis and electrochemical probing of water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Du Feipeng; Yang Yingkui; Xie Xiaolin; Wu Kangbing; Gan Tian; Liu Lang

    2008-01-01

    Water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes (MWNT-g-P(SSS-co-AA)) with core-shell nanostructure were successfully synthesized by in situ free radical copolymerization of sodium 4-strenesulfonate (SSS) and acrylic acid (AA) in the presence of MWNTs terminated with vinyl groups; their structure was characterized by FTIR, 1 H NMR, Raman, TGA and TEM. The results showed that the thickness and content of the copolymer layer grafted onto the MWNT surface are about 7-12 nm and 82.3%, respectively. The P(SSS-co-AA) covalently grafted on MWNTs provides MWNT-g-P(SSS-co-AA) with good hydrophilicity and solubility in water. Then a novel MWNT-g-P(SSS-co-AA)-modified glassy carbon electrode was fabricated by coating; its electrochemical properties were evaluated by electrochemical probe of K 3 [Fe(CN) 6 ], and its catalytic behaviors to the electrochemical oxidation processes of dopamine (DA) and serotonin (5-HT) were investigated. Since the MWNT-g-P(SSS-co-AA)-modified electrode possesses strong electron transfer capability, high electrochemical activity and catalytic ability, it can be used in sensitive, selective, rapid and simultaneous monitoring of biomolecules

  15. Electrocatalytic reduction of oxygen at glassy carbon electrode modified by polypyrrole/anthraquinones composite film in various pH media

    International Nuclear Information System (INIS)

    Valarselvan, S.; Manisankar, P.

    2011-01-01

    Graphical abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . Highlights: → Hydroxyl derivatives of anthraquinones as electrocatalysts for dioxygen reduction. → AQ/PPy composite film on GC electrode exhibits potent electrocatalytic activity. → Substituent groups influence electrocatalytic dioxygen reduction. → Surface coverage varies the rate of electrocatalytic dioxygen reduction. - Abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. The electrochemical behaviour of the modified electrodes was examined in various pH media and both the formal potential of anthraquinones and reduction potential of dioxygen exhibited pH dependence. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . pH 6.0 was chosen as the most suitable medium to study the electrocatalysis by comparing the peak potential of oxygen reduction and enhancement in peak current for oxygen reduction. The diffusion coefficient values of AQ at the modified electrodes and the number of electrons involved in AQ reduction were evaluated by chronoamperometric and chronocoulometric techniques, respectively. In addition, hydrodynamic voltammetric studies showed the involvement of two electrons in O 2 reduction. The mass specific activity of AQ used, the diffusion coefficient of oxygen and the heterogeneous rate constants for the oxygen reduction at the surface of modified electrodes were also determined by rotating disk voltammetry.

  16. Cobalt-Embedded Nitrogen-Rich Carbon Nanotubes Efficiently Catalyze Hydrogen Evolution Reaction at All pH Values

    Czech Academy of Sciences Publication Activity Database

    Zou, X.; Huang, X.; Goswami, A.; Silva, R.; Sathe, B. R.; Mikmeková, Eliška; Asefa, T.

    2014-01-01

    Roč. 53, č. 17 (2014), s. 4372-4376 ISSN 1433-7851 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : carbon nanotubes * cobalt nanoparticles * electrocatalysis * hydrogen evolution reaction * water splitting Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 11.261, year: 2014

  17. Degradation Kinetics of Carbon Tetrachloride by Sulfate Green Rust as Influenced by pH and Copper Ions (Stillwater)

    Science.gov (United States)

    Chlorinated solvents such as trichloroethene (TCE, C2HCl3) and carbon tetrachloride (CT, CCl4) are priority groundwater contaminants at many EPA field sites. Green rust (GR) minerals are important corrosion products of zerovalent iron (Fe0) that has been used in permeable react...

  18. Degradation Kinetics of Carbon Tetrachloride by Sulfate Green Rust as Influenced by pH and Copper Ions

    Science.gov (United States)

    Chlorinated solvents such as trichloroethene (TCE, C2HCl3) and carbon tetrachloride (CT, CCl4) are priority groundwater contaminants at many EPA field sites. Green rust (GR) minerals are important corrosion products of zerovalent iron (Fe0) that has been used in permeable reactiv...

  19. Theoretical study on the interactions between chlordecone hydrate and acidic surface groups of activated carbon under basic pH conditions.

    Science.gov (United States)

    Melchor-Rodríguez, Kenia; Gamboa-Carballo, Juan José; Ferino-Pérez, Anthuan; Passé-Coutrin, Nady; Gaspard, Sarra; Jáuregui-Haza, Ulises Javier

    2018-05-01

    A theoretical study of the influence of acidic surface groups (SG) of activated carbon (AC) on chlordecone hydrate (CLDh) adsorption is presented, in order to help understanding the adsorption process under basic pH conditions. A seven rings aromatic system (coronene) with a functional group in the edge was used as a simplified model of AC to evaluate the influence of SG in the course of adsorption from aqueous solution at basic pH conditions. Two SG were modeled in their deprotonated form: carboxyl and hydroxyl (COO - and O - ), interacting with CLDh. In order to model the solvation process, all systems under study were calculated with up to three water molecules. Multiple Minima Hypersurface (MMH) methodology was employed to study the interactions of CLDh with SG on AC using PM7 semiempirical Hamiltonian, to explore the potential energy surfaces of the systems and evaluate their thermodynamic association energies. The re-optimization of representative structures obtained from MMH was done using M06-2X Density Functional Theory. The Quantum Theory of Atoms in Molecules (QTAIM) was used to characterize the interaction types. As result, the association of CLDh with acidic SG at basic pH conditions preferentially occurs between the two alcohol groups of CLDh with COO - and O - groups and by dispersive interactions of chlorine atoms of CLDh with the graphitic surface. On the other hand, the presence of covalent interactions between the negatively charged oxygen of SG and one hydrogen atom of CLDh alcohol groups (O - ⋯HO interactions) without water molecules, was confirmed by QTAIM study. It can be concluded that the interactions of CLDh with acidic SG of AC under basic pH conditions confirms the physical mechanisms of adsorption process. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Honeycomb-inspired design of ultrafine SnO2@C nanospheres embedded in carbon film as anode materials for high performance lithium- and sodium-ion battery

    Science.gov (United States)

    Ao, Xiang; Jiang, Jianjun; Ruan, Yunjun; Li, Zhishan; Zhang, Yi; Sun, Jianwu; Wang, Chundong

    2017-08-01

    Tin oxide (SnO2) has been considered as one of the most promising anodes for advanced rechargeable batteries due to its advantages such as high energy density, earth abundance and environmental friendly. However, its large volume change during the Li-Sn/Na-Sn alloying and de-alloying processes will result in a fast capacity degradation over a long term cycling. To solve this issue, in this work we design and synthesize a novel honeycomb-like composite composing of carbon encapsulated SnO2 nanospheres embedded in carbon film by using dual templates of SiO2 and NaCl. Using these composites as anodes both in lithium ion batteries and sodium-ion batteries, no discernable capacity degradation is observed over hundreds of long term cycles at both low current density (100 mA g-1) and high current density (500 mA g-1). Such a good cyclic stability and high delivered capacity have been attributed to the high conductivity of the supported carbon film and hollow encapsulated carbon shells, which not only provide enough space to accommodate the volume expansion but also prevent further aggregation of SnO2 nanoparticles upon cycling. By engineering electrodes of accommodating high volume expansion, we demonstrate a prototype to achieve high performance batteries, especially high-power batteries.

  1. Effects of sodium bicarbonate concentration on growth, photosynthesis, and carbonic anhydrase activity of macroalgae Gracilariopsis lemaneiformis, Gracilaria vermiculophylla, and Gracilaria chouae (Gracilariales, Rhodophyta).

    Science.gov (United States)

    Zhou, Wei; Sui, Zhenghong; Wang, Jinguo; Hu, Yiyi; Kang, Kyoung Ho; Hong, Hye Ran; Niaz, Zeeshan; Wei, Huihui; Du, Qingwei; Peng, Chong; Mi, Ping; Que, Zhou

    2016-06-01

    There is potential for bicarbonate to improve crop yields and economic efficiency of marine algae. However, few studies have focused on the effect of bicarbonate on the growth, photosynthesis, and enzyme activity associated with carbon utilization, especially in commercial macroalgae. Here, the addition of bicarbonate (up to 420 mg L(-1)) to macroalgal cultures has been evaluated for Gracilariopsis lemaneiformis, Gracilaria vermiculophylla, and Gracilaria chouae with respect to growth rate, photosynthetic activity, carbonic anhydrase activity, and biochemical composition. The results showed that the effects of NaHCO3 on growth, chlorophyll a, phycoerythrin, photosynthetic oxygen evolution, photochemical parameters of PSI and PSII, carbonic anhydrase activity, and nitrogen content were significant (P 336 mg L(-1) for Gp. lemaneiformis and >420 mg L(-1) for the other two species). Moreover, species-specific differences induced by supplementation with bicarbonate were discovered during culture. Optimal concentrations of NaHCO3 used in this study were 252 mg L(-1) for Gp. lemaneiformis and 336 mg L(-1) for G. vermiculophylla and G. chouae. These results suggest that an adequate supplementation of sodium bicarbonate is a viable strategy for promoting growth and photosynthetic activity in some macroalgae as well as for improving biochemical composition. The study will help to accelerate the growth rate of algae and improve the quality of thalli, and will also be useful for enhancing the understanding of carbon utilization in macroalgae.

  2. Decomposition of Sodium Tetraphenylborate

    International Nuclear Information System (INIS)

    Barnes, M.J.

    1998-01-01

    The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate (NaTPB) has been investigated. The focus of the investigation is on the determination of additives and/or variables which influence NaTBP decomposition. This document describes work aimed at providing better understanding into the relationship of copper (II), solution temperature, and solution pH to NaTPB stability

  3. Effect of carbon dioxide on the rate of iodine vapor absorption by aqueous solution of sodium hydroxide

    International Nuclear Information System (INIS)

    Eguchi, Wataru; Adachi, Motonari; Miyake, Yoshikazu

    1978-01-01

    There is always carbon dioxide in the atmosphere as an impurity. Since this is an acid gas similar to iodine, each absorption rate seems to be affected by the other due to the coexistence of these two. Experiments have been conducted to clarify the absorption rate and absorption mechanism of iodine in the simultaneous absorption of iodine and carbon dioxide. Carbon dioxide coexisting with gas phases as an impurity decreases the absorption rate of iodine in the removal by washing with water of iodine mixed in the air. The first cause of this is that the diffusion coefficient of iodine in gas phase decreases with the carbon dioxide content in the gas phase. The second cause is that coexistent carbon dioxide is an acid gas, dissociates by dissolving into the absorbing solution, increases hydrogen ion concentration together with the formation of negative ions of bicarbonate and carbonate, and reduces hydroxyl ion concentration as a result. It is more important that existence of iodine has a catalytic effect to the rate of basic catalytic hydrolysis of carbon dioxide simultaneously dissolved in water phase, and accelerates this reaction rate. The mechanism of catalytic effect of iodine for the hydrolysis of carbon dioxide can not be clarified in detail only by this experiment, but the simultaneous absorption rate of iodine and carbon dioxide can be explained satisfactorily. (Wakatsuki, Y

  4. Iodine evolution and pH control

    International Nuclear Information System (INIS)

    Beahm, E.C.; Lorenz, R.A.; Weber, C.F.

    1993-01-01

    The pH is the major factor in determining the extent of I 2 in solution. In containment where no pH-control chemicals are present, the acidity or basicity of the water pool will be determined by materials that are introduced into containment as a result of the accident itself. These materials may be fission products (i.e., cesium compounds), thermally produced products (i.e., core-concrete aerosols), or compounds produced by radiation (i.e., nitric acid). In situations where pH levels fall below ∼7, the formation of I 2 will occur in irradiated iodide solutions. A correlation between pH and iodine formation is needed so that the amounts I 2 in water pools can be assessed. This, in turn, determines the amount of I 2 in the atmosphere available for escape by containment leakage. A number of calculational routines based on more than 100 differential equations representing individual reactions can be found in the literature. In this work, it is shown that a simpler approach based on the steady-state decomposition of hydrogen peroxide should correctly describe iodine formation in severe accidents. Comparisons with test data show this approach to be valid. The most important acids in containment will be nitric acid (HNO 3 ), produced by irradiation of water and air, and hydrochloric acid (HCl), produced by irradiation or heating of electrical cable insulation. The most important bases in containment will be cesium hydroxide, cesium borate (or cesium carbonate), and in some plants pH additives, such as sodium hydroxide or sodium phosphate

  5. Reconstruction of pH and partial pressure of carbon dioxide during the Mesozoic era period using boron and oxygen isotopic compositions of fresh ammonoids & nautiloids

    Science.gov (United States)

    Kawahata, Hodaka; Fukushima, Ayaka; Moriya, Kazuyori; Ishikawa, Tsuyoshi; Suzuki, Atsushi; Tanabe, Kazushige

    2013-04-01

    The increase of partial pressure of carbon dioxide (pCO2) in the atmosphere induces global warming and ocean acidification at the modern condition. The reconstruction of pCO2 during the geological time is required together with proxy calibration by laboratory experiments to predict the future environments. Boron isotopic ratio is an excellent proxy for pH and the relevant partial pressure of carbon dioxide in the seawater (PCO2). This study is the first to quantify pH dependence of delta 11B of the ammonoids and nautiloids mainly in the Cretaceous and in Jurassic (70-162 Ma), which are expected to be much warmer due to higher PCO2. However, no reliable reconstruction data using foraminiferal delta 11B before Cenozoic era has been reported. We used the very fresh aragonite shells of ammonoids and nautiloids by big advantages. Since aragonite changes into secondary calcite by diagenesis, it is easy and effective to identify the degree of alteration at each sample by measuring calcite/aragonite ratio. Also we carefully conducted the assessment of secondary alteration from three perspectives: 1) Determination of calcite/aragonite ratio by X-ray diffraction (XRD), 2) Observation of microstructures of the nacreous layers by scanning electron microscope (SEM), and 3) Measurement of trace element contents and stable isotope ratios. We conducted high precision boron isotope analysis of biogenic carbonates with +/- 0.1 per mil reproducibility by adopting positive thermal ionization mass spectrometry (P-TIMS) methods. Also we analyzed delta 18O to estimate paleo-temperature, at which biogenic aragonite was formed. Combination of delta 11B and delta 18O of biogenic aragonite in 80 Ma and 86 Ma revealed that deeper dwellers showed lower delta 11B values, which corresponded to lower pH. This feature is consistent with those observed in the modern vertical water column. The respective shallow water temperature was 19.7 and 19.1 centigrade. Based on these results, the

  6. Mechanistic deductions from multiple kinetic and solvent deuterium isotope effects and pH studies of pyridoxal phosphate dependent carbon-carbon lyases: escherichia coli tryptophan indole-lyase

    International Nuclear Information System (INIS)

    Kiick, D.M.; Phillips, R.S.

    1988-01-01

    Analysis of the pH dependence of the kinetic parameters and competitive inhibitor Ki values for tryptophan indole-lyase suggests two enzymic groups must be unprotonated in order to facilitate binding and catalysis of tryptophan. The V/K for tryptophan and the pKi for oxindolyl-L-alanine, a putative transition state analogue and competitive inhibitor, decrease below two pK values of 7.6 and 6.0, while the Ki for L-alanine, also a competitive inhibitor, is 3300-fold larger (20 mM) than that for oxindolyl-L-alanine and increases below a single pK of 7.6. A single pK of 7.6 is also observed in the V/K profile for the alternate substrate, S-methyl-L-cysteine. Therefore, the enzymic group with a pK of 7.6 is responsible for proton abstraction at the 2-position of tryptophan, while the enzymic group with a pK of 6.0 interacts with the indole portion of tryptophan and probably catalyzes formation of the indolenine tautomer of tryptophan (in concert with proton transfer to C-3 of indole from the group with pK 7.6) to facilitate carbon-carbon bond cleavage and elimination of indole. The pH variation of the primary deuterium isotope effects for proton abstraction at the 2-position of tryptophan (DV = 2.5 and D(V/Ktrp) = 2.8) are pH independent, while the Vmax for tryptophan or S-methyl-L-cysteine is the same and also pH independent. Thus, substrates bind only to the correctly protonated form of the enzyme. Further, tryptophan is not sticky, and the pK values observed in both V/K profiles are the correct ones

  7. Effects of medium, carbon and nitrogen source, pH and light on the growth of Mycosphaerella musicola

    OpenAIRE

    Montarroyos, Angélica Virgínia Valois; Coelho, Rildo Sartori Barbosa; Ferraz, Gabriela de Morais Guerra; Santos, Rômulo dos; Santos, Venézio Felipe dos; Andrade, Paulo Paes de

    2007-01-01

    Este trabalho objetivou o estabelecimento de condições favoráveis ao crescimento micelial de M. musicola in vitro, pela avaliação em quatro experimentos, da influência de diferentes meios de cultura (BDA, BDA/IFB, V8, V8/IFB, V8/CaCO3 e V8/CaCO3/IFB); combinações de fontes de carbono (dextrose, maltose, sacarose e xilose) e nitrogênio (peptona, glicina, nitrato de potássio e de sódio); valores de pH (6,8; 6,4; 5,7 e 4,9) e regimes luminosos (escuro contínuo, alternância luminosa e claro contí...

  8. EFFECT OF pH ON ELECTROLESS Ni-P COATING OF CONDUCTIVE AND NON-CONDUCTIVE MATERIALS

    Directory of Open Access Journals (Sweden)

    Subrata Roy

    2011-12-01

    Full Text Available Electroless nickel-phosphorus (Ni-P coating of carbon steel as well as a polypropylene substrate was conducted using sodium hypophosphite as a reducing agent in alkaline media. The influence of pH on coating appearances and the properties of the coatings for both steel and the polypropylene substrate were studied. A nickel-phosphorus coating of good appearance was obtained in the pH range between 5.5 and 12.5 on the carbon steel substrate and between 8.5 and 12 on the polypropylene substrate. The percentage of Ni content in the coating increased with increasing pH of the bath solution. A smooth, uniform microstructure was found in the coating deposited in relatively lower pH solutions compared to higher pH baths. The microhardness of the Ni-P coating decreased with an increasing percentage Ni content in the deposit.

  9. Sodium Bicarbonate mouth rinse: An Uncommon Complication

    OpenAIRE

    Fatih Mehmet Coskunses

    2012-01-01

    Sodium bicarbonate is a natural buffer that maintains a healthy pH in mouth to promote a clean and fresh oral environment. Sodium-bicarbonate rinse is empirically suggested to patients by dentist and people around, and may prove to be harmful. In this short communication, we present chemical burn of oral mucosa because of sodium-bicarbonate rinse after misfit dental impression.

  10. Evaluation of sampling methods for measuring exposure to volatile inorganic acids in workplace air. Part 2: Sampling capacity and breakthrough tests for sodium carbonate-impregnated filters.

    Science.gov (United States)

    Demange, Martine; Oury, Véronique; Rousset, Davy

    2011-11-01

    In France, the MétroPol 009 method used to measure workplace exposure to inorganic acids, such as HF, HCl, and HNO3, consists of a closed-face cassette fitted with a prefilter to collect particles, and two sodium carbonate-impregnated filters to collect acid vapor. This method was compared with other European methods during the development of a three-part standard (ISO 21438) on the determination of inorganic acids in workplace air by ion chromatography. Results of this work, presented in a companion paper, led to a need to go deeper into the performance of the MétroPol 009 method regarding evaluation of the breakthrough of the acids, both alone and in mixtures, interference from particulate salts, the amount of sodium carbonate required to impregnate the sampling filter, the influence of sampler components, and so on. Results enabled improvements to be made to the sampling device with respect to the required amount of sodium carbonate to sample high HCl or HNO3 concentrations (500 μL of 5% Na2CO3 on each of two impregnated filters). In addition, a PVC-A filter used as a prefilter in a sampling device showed a propensity to retain HNO3 vapor so a PTFE filter was considered more suitable for use as a prefilter. Neither the material of the sampling cassette (polystyrene or polypropylene) nor the sampling flowrate (1 L/min or 2 L/min) influenced the performance of the sampling device, as a recovery of about 100% was achieved in all experiments for HNO3, HCl, and HF, as well as HNO3+HF and HNO3+HCl mixtures, over a wide range of concentrations. However, this work points to the possibility of interference between an acid and salts of other acids. For instance, interference can occur through interaction of HNO3 with chloride salts: the stronger the acid, the greater the interference. Methods based on impregnated filters are reliable for quantitative recovery of inorganic volatile acids in workplace atmosphere but are valuable only in the absence of interferents.

  11. Effect of pH on saturated hydraulic conductivity and soil dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, D.L.; Roades, J.D.; Lavado, R.; Grieve, C.M.

    The adverse effects of exchangeable sodium on soil hydraulic conductivity (K) are well known, but at present only sodicity and total electrolyte concentration are used in evaluating irrigation water suitability. In arid areas, high sodicity is often associatd with high dissolved carbonate and thus high pH, but in humid areas high sodicity may be associated with low pH. To evaluate the effect of pH (as an independent variable) on K, solutions with the same SAR and electrolyte level were prepared at pH 6, 7, 8, and 9. Saturated K values were determined at constant flux in columns packed at a bulk density of 1.5 Mg m/sup -3/. At pH 9, saturated K values were lower than at pH 6 for a montmorillonitic and kaolinitic soil. For a vermiculitic soil with lower organic carbon and higher silt content, pH changes did not cause large K differences. Decreases in K were not reversible on application of waters with higher electrolyte levels. The results from the K experiments were generally consistent with optical transmission measurements of dispersion. Although anion adsorption was at or below detection limits and cation exchange capacity (CEC) was only slightly dependent on pH, differences in pH effects on K among soils are likely due to differences in quantities of variable-charge minerals and organic matter.

  12. Carbon with Expanded and Well-Developed Graphene Planes Derived Directly from Condensed Lignin as a High-Performance Anode for Sodium-Ion Batteries.

    Science.gov (United States)

    Yoon, Dohyeon; Hwang, Jieun; Chang, Wonyoung; Kim, Jaehoon

    2018-01-10

    In this study, we demonstrate that lignin, which constitutes 30-40 wt % of the terrestrial lignocellulosic biomass and is produced from second generation biofuel plants as a cheap byproduct, is an excellent precursor material for sodium-ion battery (NIB) anodes. Because it is rich in aromatic monomers that are highly cross-linked by ether and condensed bonds, the lignin material carbonized at 1300 °C (C-1300) in this study has small graphitic domains with well-developed graphene layers, a large interlayer spacing (0.403 nm), and a high micropore surface area (207.5 m 2 g -1 ). When tested as an anode in an NIB, C-1300 exhibited an initial Coulombic efficiency of 68% and a high reversible capacity of 297 mA h g -1 at 50 mA g -1 after 50 cycles. The high capacity of 199 mA h g -1 at less than 0.1 V with a flat voltage profile and an extremely low charge-discharge voltage hysteresis (sugar-derived carbons and a low-temperature carbonized sample (900 °C), the reasons for the excellent performance of C-1300 were determined to result from facilitated Na + -ion transport to the graphitic layer and the microporous regions that penetrate through the less defective and enlarged interlayer spacings.

  13. Kinetic of formation for single carbon dioxide and mixed carbon dioxide and tetrahydrofuran hydrates in water and sodium chloride aqueous solution

    NARCIS (Netherlands)

    Sabil, K.M.; Duarte, A.R.C.; Zevenbergen, J.F.; Ahmad, M.M.; Yusup, S.; Omar, A.A.; Peters, C.J.

    2010-01-01

    A laboratory-scale reactor system is built and operated to measure the kinetic of formation for single and mixed carbon dioxide-tetrahydrofuran hydrates. The T-cycle method, which is used to collect the kinetic data, is briefly discussed. For single carbon dioxide hydrate, the induction time

  14. Characterization of Sodium Carbonate (Na2CO3) Treated Rice Husk Activated Carbon and Adsorption of Lead from Car Battery Wastewater

    Science.gov (United States)

    Hanum, F.; Bani, O.; Izdiharo, A. M.

    2017-03-01

    The use of rice husk as adsorbent would not only reduce its disposal problems, but would also produce value-added products, such as activated carbon derived from rice husk. This study aimed to determine the optimum carbonization temperature for activated carbon production from rice husk and its adsorption performance on Pb in car battery wastewater. In this study, activated carbon was produced by carbonizing rice husk 400-600 °C for 90-150 minutes followed by chemical activation using 5% Na2CO3 and sieving to 100 meshes. Lead adsorption was measured using atomic absorption spectroscopy (AAS). Results suggested that highest carbon yield of 47.75% was obtained for carbonization at 500 °C for 150 minutes. At that condition, produced activated carbon contained 3.35% moisture, 30.86% ash, 18.04% volatile matter. The adsorption capacity was found to be 0.6007 mg lead/g adsorbent with % adsorpsi 58.08%

  15. Stability of sodium bicarbonate injection 8.4% in syringes over a six-week period in refrigerated temperature.

    Science.gov (United States)

    Seki, Jack T; Wang, Tian Q; Yip, Paul M; Mazzulli, Tony; Minden, Mark D

    2018-04-01

    Background Dysfunctional central venous catheter prohibits the administration of potential life-saving chemotherapy and the delivery of essential supportive care needs to patients. Sodium bicarbonate injection has been shown to impede against fibrin clot formation and prolong prothrombin time and thrombin clotting time. Sodium bicarbonate injection has been tried as a second-line agent with good results in a small number of patients (internal data not published) when alteplase failed. We assessed whether the pre-filled sodium bicarbonate injection in 5 mL syringes would not only preserve sterility and retain its pH and concentration but also amount to the potential cost savings for future use when stored in a refrigerated environment. Methodology Twelve pre-filled 5 mL syringes were prepared aseptically, of which four each were tested for pH, sodium bicarbonate injection concentration and sterility when stored in refrigerated temperature over a six-week period. A standard pH meter, enzymatic carbon dioxide analyzer, and a 14-day incubation for microbial detection were employed for this study. Results Sodium bicarbonate concentration measured in the form of carbon dioxide ranged from 923 mmol/L or (1846 mosol/L) to 1006 mmol/L or (2012 mosmol/L), and pH ranged from (7.88 to 8.05) were reported over the duration of the study period. The 14-day incubation period resulted in no microbial growth. Conclusion Our study results have indicated that the pH and sodium bicarbonate injection concentration values were stable and within range, comparable to those reported by the manufacturer within the study period. The contents of the subdivided sodium bicarbonate injection 5 mL syringes retained sterility over a 14-day incubation period.

  16. The Pochonia chlamydosporia serine protease gene vcp1 is subject to regulation by carbon, nitrogen and pH: implications for nematode biocontrol.

    Science.gov (United States)

    Ward, Elaine; Kerry, Brian R; Manzanilla-López, Rosa H; Mutua, Gerald; Devonshire, Jean; Kimenju, John; Hirsch, Penny R

    2012-01-01

    The alkaline serine protease VCP1 of the fungus Pochonia chlamydosporia belongs to a family of subtilisin-like enzymes that are involved in infection of nematode and insect hosts. It is involved early in the infection process, removing the outer proteinaceous vitelline membrane of nematode eggs. Little is known about the regulation of this gene, even though an understanding of how nutrients and other factors affect its expression is critical for ensuring its efficacy as a biocontrol agent. This paper provides new information on the regulation of vcp1 expression. Sequence analysis of the upstream regulatory region of this gene in 30 isolates revealed that it was highly conserved and contained sequence motifs characteristic of genes that are subject to carbon, nitrogen and pH-regulation. Expression studies, monitoring enzyme activity and mRNA, confirmed that these factors affect VCP1 production. As expected, glucose reduced VCP1 expression and for a few hours so did ammonium chloride. Surprisingly, however, by 24 h VCP1 levels were increased in the presence of ammonium chloride for most isolates. Ambient pH also regulated VCP1 expression, with most isolates producing more VCP1 under alkaline conditions. There were some differences in the response of one isolate with a distinctive upstream sequence including a variant regulatory-motif profile. Cryo-scanning electron microscopy studies indicated that the presence of nematode eggs stimulates VCP1 production by P. chlamydosporia, but only where the two are in close contact. Overall, the results indicate that readily-metabolisable carbon sources and unfavourable pH in the rhizosphere/egg-mass environment may compromise nematode parasitism by P. chlamydosporia. However, contrary to previous indications using other nematophagous and entomopathogenic fungi, ammonium nitrate (e.g. from fertilizers) may enhance biocontrol potential in some circumstances.

  17. The Pochonia chlamydosporia serine protease gene vcp1 is subject to regulation by carbon, nitrogen and pH: implications for nematode biocontrol.

    Directory of Open Access Journals (Sweden)

    Elaine Ward

    Full Text Available The alkaline serine protease VCP1 of the fungus Pochonia chlamydosporia belongs to a family of subtilisin-like enzymes that are involved in infection of nematode and insect hosts. It is involved early in the infection process, removing the outer proteinaceous vitelline membrane of nematode eggs. Little is known about the regulation of this gene, even though an understanding of how nutrients and other factors affect its expression is critical for ensuring its efficacy as a biocontrol agent. This paper provides new information on the regulation of vcp1 expression. Sequence analysis of the upstream regulatory region of this gene in 30 isolates revealed that it was highly conserved and contained sequence motifs characteristic of genes that are subject to carbon, nitrogen and pH-regulation. Expression studies, monitoring enzyme activity and mRNA, confirmed that these factors affect VCP1 production. As expected, glucose reduced VCP1 expression and for a few hours so did ammonium chloride. Surprisingly, however, by 24 h VCP1 levels were increased in the presence of ammonium chloride for most isolates. Ambient pH also regulated VCP1 expression, with most isolates producing more VCP1 under alkaline conditions. There were some differences in the response of one isolate with a distinctive upstream sequence including a variant regulatory-motif profile. Cryo-scanning electron microscopy studies indicated that the presence of nematode eggs stimulates VCP1 production by P. chlamydosporia, but only where the two are in close contact. Overall, the results indicate that readily-metabolisable carbon sources and unfavourable pH in the rhizosphere/egg-mass environment may compromise nematode parasitism by P. chlamydosporia. However, contrary to previous indications using other nematophagous and entomopathogenic fungi, ammonium nitrate (e.g. from fertilizers may enhance biocontrol potential in some circumstances.

  18. Background electrolytes and pH effects on selenate adsorption using iron-impregnated granular activated carbon and surface binding mechanisms.

    Science.gov (United States)

    Zhang, Ning; Gang, Daniel Dianchen; McDonald, Louis; Lin, Lian-Shin

    2018-03-01

    Iron-impregnated granular activated carbon (Fe-GAC) has been shown effective for selenite adsorptive removal from aqueous solutions, but similar effectiveness was not observed with selenate. This study examined the effects of background electrolytes and pH on selenate adsorption on to Fe-GAC, and surface bindings to elucidate the selenate adsorption mechanisms. The decrease magnitude of selenate adsorption capacity under three background electrolytes followed the order: LiCl > NaCl > KCl, as ionic strength increased from 0.01 to 0.1 M. Larger adsorption capacity differences among the three electrolytes were observed under the higher ionic strengths (0.05 and 0.1 M) than those under 0.01 M. Multiplet peak fittings of high resolution X-ray photoelectron spectra for O1s and Fe2p 3/2 indicated the presence of iron (III) on adsorbent surface. pH variations during the adsorbent preparation within 3-8 in NaCl solutions did not cause appreciable changes in the iron redox state and composition. Raman spectra showed the formation of both monodentate and bidentate inner sphere complexes under pHs adsorption under alkaline conditions. Mechanisms for monodentate and bidentate formations and a stable six-member ring structure were proposed. Two strategies were recommended for modifying Fe-GAC preparation procedure to enhance the selenate adsorption: (1) mixed-metal oxide coatings to increase the point of zero charge (pH zpc ); and (2) ferrous iron coating to initially reduce selenate followed by selenite adsorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The radiation chemistry of aqueous sodium terephthalate solutions

    International Nuclear Information System (INIS)

    Matthews, R.W.

    1980-04-01

    The radiation chemistry of cobalt-60 gamma-irradiated aqueous sodium terephthalate solutions has been studied. In aerated 4 x 10 -4 M sodium hydroxide solutions, the main products are hydroxyterephthalate (HTA) (G = 0.99 +- 0.01), carbonate (G = 1.31 +- 0.08), and peroxides (G = 2.84 +- 0.04). The HTA and carbonate species are both formed as a result of hydroxyl radical attack and account for approximately 90 per cent of hydroxyl radical reactions. Oxygen needs to be present for efficient conversion of the terephthalate-OH radical adduct to HTA and oxygenation increases G(HTA) above the aerated solution value. G(HTA) is unaffected by changes in terephthalate concentration between 1 x 10 -4 M and 1 x 10 -2 M in sodium hydroxide solutions at pH 10. Decreasing the solution pH does however affect G(HTA). In phosphate buffered solutions pH 6.85, G(HTA) is 0.93 +- 0.01 and lower values are obtained with further decrease in solution pH. The lowering of the G(HTA) value is attributed to recombination reactions between the terephthalate-OH radical products and reducing radical products. Experimental evidence supporting the recombination postulate was obtained from the measurement of a parallel decrease in the peroxide yield and the observation of a dose rate effect on G(HTA). Competition kinetic studies with the added solutes carbonate and bicarbonate gave the rate ratios k (OH + TA 2- ) : k(OH + CO 3 2- ) : k(OH + HCO 3 - ) = 1 : 0.105 : 0.0036

  20. The effect of sulfide on the aerobic corrosion of carbon steel in near-neutral pH saline solutions

    International Nuclear Information System (INIS)

    Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

    2013-01-01

    Highlights: ► The corrosion rate is low when steel is exposed to anaerobic conditions (pH = 8.9). ► An anaerobic to aerobic corrosion with sulfide switch increases the corrosion rate. ► Aerobic exposure induces the formation of goethite-covered tubercles. ► Continual sulfide exposure leads to the slow conversion of goethite to mackinawite. - Abstract: Severe corrosion damage may occur when gas transmission pipelines are exposed, at disbonded coating locations, to trapped waters containing sulfide followed by secondary exposure to air. Aerobic corrosion with sulfide was investigated in a long-term corrosion experiment in which corrosion was monitored by measurement of the corrosion potential and polarization resistance obtained from linear polarization resistance measurements. The properties and composition of the corrosion product deposits formed were determined using scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy. A switch from aerobic to aerobic-with-sulfide corrosion doubles the relative corrosion rate.

  1. Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes

    International Nuclear Information System (INIS)

    Holm, Allan Hjarbaek; Vase, Karina Hojrup; Winther-Jensen, Bjorn; Pedersen, Steen Uttrup; Daasbjerg, Kim

    2007-01-01

    The hydroquinone/quinone (H 2 Q/Q) redox system was tethered to glassy carbon surfaces using first an electrochemical pre-oxidation treatment to afford carboxylic acid functionalities followed by immobilizing the H 2 Q precursor, n-(2,5-dimethoxyphenyl)alkan-1-amine (general structure: H 2 N-(CH 2 ) n -C 6 H 3 (OCH 3 ) 2 , n = 1, 2, 4, 8, and 12), by carbodiimide chemistry and a final demethylation reaction. The resultant surfaces exhibited the expected chemical reversibility in aqueous solution with a pH-sensitive position of the formal potential (∼55 mV/pH unit), and an increase in the peak potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics was faster than expected for longer alkyl spacers. We suggest that film disorder, electrode-mediating effects, and a roughened electrode material could account for these apparent inconsistencies. To further understand such effects, two complementary electrode modification strategies leading to better film ordering on carbon were adapted; immobilizing a thin layer of benzoic acid by oxidative deposition of 4-aminobenzoic acid or employing a plasma deposition process to tether an acid analogue. Analysis of the various electrodes was accomplished by electrochemical methods, atomic force microscopy, and X-ray photoelectron spectroscopy

  2. Ultrathin molybdenum diselenide nanosheets anchored on multi-walled carbon nanotubes as anode composites for high performance sodium-ion batteries

    Science.gov (United States)

    Zhang, Zhian; Yang, Xing; Fu, Yun; Du, Ke

    2015-11-01

    Ultrathin molybdenum diselenide nanosheets are decorated on the surface of multi-walled carbon nanotubes (MWCNT) via a one-step hydrothermal method. Uniform MoSe2 nanosheets are firmly anchored on MWCNT according to the characterizations of scanning electron microscope (SEM), transmission electron microscope (TEM). When evaluated as anodes for sodium storage, the MoSe2@MWCNT composites deliver a reversible specific capacity of 459 mAh g-1 at a current of 200 mA g-1 over 90 cycles, and a specific capacity of 385 mAh g-1 even at a current rate of 2000 mAh g-1, which is better than the MoSe2 nanosheets. The enhanced electrochemical performance of the MoSe2@MWCNT composites can be ascribed to the synergic effects of MoSe2 nanosheets and MWCNT. The high capacity and good rate performance reveal that the MoSe2@MWCNT composites are very promising for applications in sodium-ion batteries.

  3. A green and efficient method to produce graphene for electrochemical capacitors from graphene oxide using sodium carbonate as a reducing agent

    Science.gov (United States)

    Jin, Yuhong; Huang, Shuo; Zhang, Mei; Jia, Mengqiu; Hu, Dong

    2013-03-01

    The green and efficient synthesis of graphene using sodium carbonate (Na2CO3) as a chemical reducing agent was studied. Extensive characterization confirmed the formation of graphene from graphene oxide using a Na2CO3 solution. The C/O atomic ratio of the as-prepared graphene has increased from 2.48 to 8.15 after reduction as determined by X-ray photoelectron spectroscopy. The conductivity of as-prepared graphene sheets is as high as 10 S m-1. After electrochemical measurements, gravimetric capacitances of 228 and 166 F g-1 at current densities of 5 and 25 mA cm-2, respectively, were obtained with KOH electrolyte.

  4. The dismantling of fast reactors: sodium processing

    International Nuclear Information System (INIS)

    Rodriguez, G.; Berte, M.; Serpante, J.P.

    1999-01-01

    Fast reactors require a coolant that does not slow down neutrons so water can not be used. Metallic sodium has been chosen because of its outstanding neutronic and thermal properties but sodium reacts easily with air and water and this implies that sodium-smeary components can not be considered as usual nuclear wastes. A stage of sodium neutralizing is necessary in the processing of wastes from fast reactors. Metallic sodium is turned into a chemically stable compound: soda, carbonates or sodium salts. This article presents several methods used by Framatome in an industrial way when dismantling sodium-cooled reactors. (A.C.)

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

    Science.gov (United States)

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

    2015-01-01

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

  6. Modeling Effects of Bicarbonate Release on Carbonate Chemistry and pH of the North Sea: A Pilot Study for Atmospheric CO2 Reduction

    Science.gov (United States)

    Lettmann, K.; Kirchner, J.; Schnetger, B.; Wolff, J. O.; Brumsack, H. J.

    2016-12-01

    Rising CO2-emissions accompanying the industrial revolution are the main drivers for climate change and ocean acidification. Several methods have been developed to capture CO2 from effluents and reduce emission. Here, we consider a promising approach that mimics natural limestone weathering: CO2 in effluent gas streams reacts with calcium carbonate in a limestone suspension. The resulting bicarbonate-rich solution can be released into natural systems. In comparison to classical carbon capture and storage (CCS) methods this artificial limestone weathering is cheaper and does not involve using toxic chemical compounds. Additionally there is no need for the controversially discussed storage of CO2 underground. The reduction of CO2-emissions becomes more important for European industries as the EU introduced a system that limits the amount of allowable CO2-emissions. Therefore, large CO2 emitters are forced to find cheap methods for emission reduction, as they often cannot circumvent CO2-production. The method mentioned above is especially of interest for power plants located close to the coast that are already using seawater for cooling purposes. Thus, it is important to estimate the environmental effects if several coastal power plants will release high amounts of bicarbonate-rich waters into coastal waters, e.g. the North Sea. In a first pilot study, the unstructured-grid finite-volume community ocean model (FVCOM) was combined with a chemical submodul (mocsy 2.0) to model the hydrodynamic circulation and mixing of bicarbonate-rich effluents from a gas power plant located at the German North Sea coast. Here, we present the first preliminary results of this project, which include modelled changes of the North Sea carbonate system and changes in pH value after the introduction of these bicarbonate-rich waters on short time scales up to one year.

  7. Influence of metallurgical phase transformation on crack propagation of 15-5PH stainless steel and 16MND5 low carbon steel

    International Nuclear Information System (INIS)

    Liu, J.

    2012-01-01

    This study focuses on the effects of phase transformations on crack propagation. We want to understand the changes of fracture toughness during welding. In this work, fracture toughness is expressed by J-integral. There are many experimental methods to obtain the critical toughness JIC but they are impractical for our investigation during phase transformation. That is the reason why we have proposed a method coupling mechanical tests, digital image correlation and finite element simulation. The fracture tests are implemented on pre-cracked single edge notched plate sample which is easy for machining and heat conduct during phase transformation. The tests are conducted at different temperatures until rupture. Digital image correlation gives us the displacement information on every sample. Each test is then simulated by finite element where the fracture toughness is evaluated by the method G-Theta at the crack propagation starting moment found by potential drop method and digital image correlation technical. Two materials have been studied, 15Cr-5Ni martensitic precipitation hardening stainless steel and 16MND5 ferritic low carbon steel. For these two materials, different test temperatures were chosen before, during and after phase transformation for testing and failure characterization of the mechanical behavior. Investigation result shows that metallurgical phase transformation has an influence on fracture toughness and further crack propagation. For 15-5PH, the result of J1C shows that the as received 15-5PH has higher fracture toughness than the one at 200 C. The toughness is also higher than the original material after one cycle heat treatment probably due to some residual austenite. Meanwhile, pure austenite 15-5PH at 200 C has higher fracture toughness than pure martensitic 15-5PH at 200 C. For 16MND5, the result also proves that the phase transformation affects fracture toughness. The as received material has bigger J1C than the situation where it was heated

  8. Final chlorine dioxide stage at near-neutral pH for bleaching eucalypt pulp

    Directory of Open Access Journals (Sweden)

    Robisnéa A. Ribeiro

    2014-01-01

    Full Text Available It is well known that pH is an important parameter for controlling the eucalyptus pulp bleaching when using the final chlorine dioxide stage, since it affects the effectiveness of the process. Recommendations found in the literature for operating are in the 3.5 to 4.0 range. However, in this paper it was shown that final chlorine dioxide has better performance, with significant brightness gain while also preserving pulp quality, when it is operated at near neutral pH. This result can be explained by the generation of sodium bicarbonate in situ upon adding carbon dioxide at this stage.

  9. PH sensor

    OpenAIRE

    Artero, C.; Nogueras Cervera, Marc; Manuel Lázaro, Antonio

    2012-01-01

    This paper presents a design of a marine instrument for the measurement of pH in seawater. The measurement system consists of a pH electrode connected to the underwater observatory OBSEA. The extracted data are useful for scientists researching ocean acidification. Peer Reviewed

  10. Molecular dynamics simulation of siderite-hematite-quartz flotation with sodium oleate

    Science.gov (United States)

    Li, Lixia; Hao, Haiqing; Yuan, Zhitao; Liu, Jiongtian

    2017-10-01

    Models of sodium oleate adsorption on siderite, hematite and quartz were investigated by molecular dynamic simulation, respectively. Surface energy was calculated to confirm the cleavage plan of hematite and quartz. Both natural cleavage plane of siderite and calculated plane were used to investigate the flotation of the three minerals. Based on the molecular simulation in solution with water as medium, adsorption quantity and interaction capability of oleate ions on the three minerals indicated that siderite could be collected efficiently by sodium oleate at neutral pH. Results of flotation experiments were further demonstrated by analysis of relative concentration of carbon atoms and oxygen atoms.

  11. Effects of the dissolved organic carbon of treated municipal wastewater on soil infiltration as related to sodium adsorption ratio and pH

    Science.gov (United States)

    Increasing scarcity of fresh water in arid and semi arid regions means that we must utilize alternative water supplies for irrigation if we are to sustain agricultural production in these regions. Treated municipal wastewaters are being increasingly utilized for irrigation. In general only the salin...

  12. Evaluation of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to prevent enamel loss after erosive challenges using an intra-oral erosion model.

    Science.gov (United States)

    Sullivan, R; Rege, A; Corby, P; Klaczany, G; Allen, K; Hershkowitz, D; Godder, B; Wolff, M

    2014-01-01

    The objective of this study was to assess the ability of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin' Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP) to prevent enamel loss from an erosive acid challenge in comparison to a silica-based dentifrice with 1450 ppm fluoride as MFP using an intra-oral erosion model. The intra-oral clinical study used a double blind, two-treatment, crossover design. A palatal retainer was used to expose the enamel specimens to the oral environment during the five-day treatment period. The retainer was designed to house three partially demineralized bovine enamel samples. The study population was composed of 24 adults, ages 18 to 70 years. The study consisted of two treatment periods, with a washout period lasting seven (+/- three) days preceding each treatment phase. A silica-based dentifrice without fluoride was used during the washout period. The Test Dentifrice used in this study contained 8% arginine and calcium carbonate (Pro-Argin Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP). The Control Dentifrice was silica-based and contained 1450 ppm fluoride as MFP. The treatment period lasted five days, during which the panelists wore the retainer 24 hours a day (except during meals and the ex vivo acid challenges) and brushed with their assigned product while wearing the retainer. The panelists brushed once in the morning and once in the evening each day for one minute, followed by a one-minute swish with the slurry and a rinse with 15 ml of water. The panelists brushed only their teeth and not the specimens directly. There were four ex vivo challenges with 1% citric acid dispersed throughout the day: two in the morning, one in the afternoon, and one in the evening. Mineral loss was monitored by a quantitative light fluorescence (QLF) technique. Twenty-three of 24 subjects successfully completed the study. The one subject who did not complete the study did so for

  13. Evaluation of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to repair acid-softened enamel using an intra-oral remineralization model.

    Science.gov (United States)

    Sullivan, R; Rege, A; Corby, P; Klaczany, G; Allen, K; Hershkowitz, D; Goldder, B; Wolff, M

    2014-01-01

    An intra-oral remineralization study was conducted to compare the ability of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP) to remineralize acid-softened bovine enamel specimens compared to a silica-based dentifrice with 1450 ppm fluoride as MFP. The intra-oral clinical study employed a double blind, two-treatment, crossover design, and used an upper palatal retainer to expose the enamel specimens to the oral environment during product use and periods of remineralization. The retainer was designed to house three partially demineralized bovine enamel samples. The study population was comprised of 30 adults, ages 18 to 70 years. The study consisted of two treatment phases with a washout period lasting seven (+/- three) days preceding each treatment phase. A silica-based dentifrice without fluoride was used during the washout period. The Test Dentifrice used in this study contained 8% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate (MFP). The Control Dentifrice was silica-based and contained 1450 ppm fluoride as MFP. The treatment period consisted of a three-day lead-in period with the assigned product. The panelists brushed two times per day during the three-day lead-in period with the assigned product. On the fourth day, the panelists began brushing with the assigned product with the retainer in their mouth. The panelists brushed for one minute, followed by a one-minute swish with the slurry and a rinse with 15 ml of water in the morning, in the afternoon, and night with the retainer in the mouth. The panelists brushed only their teeth and not the specimens directly. Changes in mineral content before and after treatment were measured using a Knoop microhardness tester. The results of the study showed that percent remineralization values for the Test Dentifrice and Control Dentifrice were 14.99% and 8.66%, respectively. A statistical analysis

  14. Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrhizal isolates from Pinus heldreichii forest

    Energy Technology Data Exchange (ETDEWEB)

    Lazarević, J.; Stojičić, D.; Keča, N.

    2016-07-01

    Aim of study: This study aims to provide basic information about physiological characteristics of isolates of Lactarius deliciosus (L.) Gray, Russula sanguinaria (Schumach.) Rauschert, Suillus collinitus (Fr) Kuntze, Suillus granulatus (L.) Rousell, Tricholoma batchii Gulden and Tricholoma imbricatum (Fr.) Kumm. Area of study: The isolates are obtained from Pinus heldreichii H. Christ forest in the south-eastern part of Montenegro. Material and methods: The isolates were molecularly characterised by internal transcribed spacer (ITS) sequencing and restriction fragment length polymorphism (RFLP) analysis. The effects of different temperatures (20, 22, 25°C), pHs (4, 4.5, 5.2, 5.8, 6.5, 7.5), and carbon (glucose, sucrose, dextrin, arabinose, xylose and starch) and nitrogen (NH4+, NO3- and protein) sources on their growth were examined under laboratory conditions. Main results: The studied factors established significant differences in the development of isolates. Isolates of R. sanguinaria, L. deliciosus and both Suillus, were characterised by faster growth at 22°C, while Tricholoma isolates grew faster at 25°C. S. granulatus, S. collinitus and T. imbticatum isolates grew well at lower pH values (4 - 5.2), while L. deliciosus, R. sanguinaria and T. bachii exhibited faster growth at pHs between 5.8 and 6.5. The examined isolates were able to utilize various carbohydrates as carbon sources. The biggest mycelial growth was characterised for sucrose, then glucose, dextrin, arabinose, starch and xylose. They grew on all examined nitrogen sources, while the biggest mycelia growth was achieved on ammonium, followed by nitrate and protein. Those characteristics varied amongst the species. Research highlights: Information about physiological characteristics of Tricholoma, Lactarius, Russula, as well as Suillus, are sparse. Hence, the data obtained in this study could contribute to the understanding of their function in ecosystems. (Author)

  15. Control of red cell volume and pH in trout: Effects of isoproterenol, transport inhibitors, and extracellular pH in bicarbonate/carbon dioxide-buffered media

    DEFF Research Database (Denmark)

    NIKINMAA, M; STEFFENSEN, JF; TUFTS, BL

    1987-01-01

    The effects of extracellular pH and beta-adrenergic stimula-tion on the volume and pH of rainbow. trout red cells were studied in HCO3-/ CO2 butfered media. A decrease in extracellular pH caused an increase in red cell volume and a decrease in intracellular pH. The pH-induced changes in cell volume......, and that the Na+/H+ exchanger is not activated by changes in intracellular pH alone. The adrenergic drug, isoproterenol, promoted cell swelling and proton extrusion even in the presence of 10 mM HCO3-, showing that the adrenergic response plays a significant role in the control of cytoplasmic pH. These responses...... were enhanced by a decrease in extracellular pH, showing that the adrenergic response is of benefit to stressed animals. DIDS markedly enhanced the effect of isoproterenol on the pHi, but abolished the increase in red cell volume. The effects of furosemide were similar to those of DIDS, suggesting...

  16. Amorphous MoS3 Infiltrated with Carbon Nanotubes as an Advanced Anode Material of Sodium-Ion Batteries with Large Gravimetric, Areal, and Volumetric Capacities

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Hualin [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Wang, Lu [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Deng, Shuo [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Zeng, Xiaoqiao [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont IL 60439 USA; Nie, Kaiqi [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Duchesne, Paul N. [Department of Chemistry, Dalhousie University, Halifax NS B3H 4R2 Canada; Wang, Bo [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Liu, Simon [Department of Chemical Engineering, University of Waterloo, Ontario N2L 3G1 Canada; Zhou, Junhua [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Zhao, Feipeng [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Han, Na [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Zhang, Peng [Department of Chemistry, Dalhousie University, Halifax NS B3H 4R2 Canada; Zhong, Jun [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Sun, Xuhui [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Li, Youyong [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Li, Yanguang [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 China; Lu, Jun [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont IL 60439 USA

    2016-11-17

    The search for earth-abundant and high-performance electrode materials for sodium-ion batteries represents an important challenge to current battery research. 2D transition metal dichalcogenides, particularly MoS2, have attracted increasing attention recently, but few of them so far have been able to meet expectations. In this study, it is demonstrated that another phase of molybdenum sulfide—amorphous chain-like MoS3—can be a better choice as the anode material of sodium-ion batteries. Highly compact MoS3 particles infiltrated with carbon nanotubes are prepared via the facile acid precipitation method in ethylene glycol. Compared to crystalline MoS2, the resultant amorphous MoS3 not only exhibits impressive gravimetric performance—featuring excellent specific capacity (≈615 mA h g-1), rate capability (235 mA h g-1 at 20 A g-1), and cycling stability but also shows exceptional volumetric capacity of ≈1000 mA h cm-3 and an areal capacity of >6.0 mA h cm-2 at very high areal loadings of active materials (up to 12 mg cm-2). The experimental results are supported by density functional theory simulations showing that the 1D chains of MoS3 can facilitate the adsorption and diffusion of Na+ ions. At last, it is demonstrated that the MoS3 anode can be paired with an Na3V2(PO4)3 cathode to afford full cells with great capacity and cycling performance.

  17. Preparation of a Si/SiO2 -Ordered-Mesoporous-Carbon Nanocomposite as an Anode for High-Performance Lithium-Ion and Sodium-Ion Batteries.

    Science.gov (United States)

    Zeng, Lingxing; Liu, Renpin; Han, Lei; Luo, Fenqiang; Chen, Xi; Wang, Jianbiao; Qian, Qingrong; Chen, Qinghua; Wei, Mingdeng

    2018-04-03

    In this work, an Si/SiO 2 -ordered-mesoporous carbon (Si/SiO 2 -OMC) nanocomposite was initially fabricated through a magnesiothermic reduction strategy by using a two-dimensional bicontinuous mesochannel of SiO 2 -OMC as a precursor, combined with an NaOH etching process, in which crystal Si/amorphous SiO 2 nanoparticles were encapsulated into the OMC matrix. Not only can such unique porous crystal Si/amorphous SiO 2 nanoparticles uniformly dispersed in the OMC matrix mitigate the volume change of active materials during the cycling process, but they can also improve electrical conductivity of Si/SiO 2 and facilitate the Li + /Na + diffusion. When applied as an anode for lithium-ion batteries (LIBs), the Si/SiO 2 -OMC composite displayed superior reversible capacity (958 mA h g -1 at 0.2 A g -1 after 100 cycles) and good cycling life (retaining a capacity of 459 mA h g -1 at 2 A g -1 after 1000 cycles). For sodium-ion batteries (SIBs), the composite maintained a high capacity of 423 mA h g -1 after 100 cycles at 0.05 A g -1 and an extremely stable reversible capacity of 190 mA h g -1 was retained even after 500 cycles at 1 A g -1 . This performance is one of the best long-term cycling properties of Si-based SIB anode materials. The Si/SiO 2 -OMC composites exhibited great potential as an alternative material for both lithium- and sodium-ion battery anodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sodium alginate: A promising biopolymer for corrosion protection of API X60 high strength carbon steel in saline medium.

    Science.gov (United States)

    Obot, I B; Onyeachu, Ikenna B; Kumar, A Madhan

    2017-12-15

    Sodium alginate (SA), a polysaccharide biopolymer, has been studied as an effective inhibitor against the corrosion of API X60 steel in neutral 3.5% NaCl using gravimetric and electrochemical techniques (OCP, EIS and EFM). The inhibition efficiency of the SA increased with concentration but was lower at higher temperature (70°C). Electrochemical measurements showed that the SA shifted the steel corrosion potential to more positive value and reduced the kinetics of corrosion by forming an adsorbed layer which mitigated the steel surface wetting, based on contact angle measurement. SEM-EDAX was used to confirm the inhibition of SA on API X60 steel surfaces. The SA adsorbs on the steel surface through a physisorption mechanism using its carboxylate oxygen according to UV-vis and ATR-IR measurements, respectively. This phenomena result in decreased localized pitting corrosion of the API X60 steel in 3.5% NaCl solution. Theoretical results using quantum chemical calculations and Monte Carlo simulations provide further atomic level insights into the interaction of SA with steel surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Carbon steel corrosion under anaerobic-aerobic cycling conditions in near-neutral pH saline solutions - Part 1: Long term corrosion behaviour

    International Nuclear Information System (INIS)

    Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

    2011-01-01

    Highlights: → Anaerobic-aerobic cycling on pipeline steel forms two distinct surface morphologies. → Seventy-five percentage of the surface was covered by a black, compact layer ∼4.5 μm thick. → A tubercle, ∼3 to 4 mm in cross section, covered the remaining 25% of surface. → The tubercle cross section showed a single large pit ∼275 μm deep. - Abstract: The influence of anaerobic-aerobic cycling on pipeline steel corrosion was investigated in near-neutral carbonate/sulphate/chloride solution (pH 9) over 238 days. The corrosion rate increased and decreased as exposure conditions were switched between redox conditions. Two distinct corrosion morphologies were observed. The majority of the surface corroded uniformly to produce a black magnetite/maghemite layer approximately 4.5 μm thick. The remaining surface was covered with an orange tubercle, approximately 3-4 mm in cross section. Analysis of the tubercle cross section revealed a single large pit approximately 275 μm deep. Repeated anaerobic-aerobic cycling localized the corrosion process within this tubercle-covered pit.

  20. An active structure preservation method for developing functional graphitic carbon dots as an effective antibacterial agent and a sensitive pH and Al(iii) nanosensor.

    Science.gov (United States)

    Hou, Peng; Yang, Tong; Liu, Hui; Li, Yuan Fang; Huang, Cheng Zhi

    2017-11-16

    Functional engineering is a crucial prerequisite for specific and wide applications of optical probes. In this study, we proposed a facile active structure preservation (ASP) method to directly develop new self-functional graphitic carbon dots (g-CDs) through a hydrothermal synthesis route by taking ciprofloxacin hydrochloride, an antibiotic belonging to a group of fluoroquinolone drugs, as an example. To retain the functional structures of the starting materials, the reaction temperature is intentionally controlled below the decomposition temperature of the reactants that hold the functional groups. As a proof of concept, we successfully prepared g-CDs with ciprofloxacin-like structures on its surface, as identified by mass spectrometric (MS) analysis. The as-prepared g-CDs not only exhibit effective antibacterial activity towards the bacteria Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), but can also optically sense pH in the range from 5.02 to 9.91. Furthermore, the g-CDs can coordinate with aluminum ions to show a chelation-enhanced photoluminescence (CHEP) effect. These results indicate that the ASP method can be promising for engineering CDs with various properties.

  1. The nature of rusts and corrosion characteristics of low alloy and plain carbon steels in three kinds of concrete pore solution with salinity and different pH

    International Nuclear Information System (INIS)

    Singh, J.K.; Singh, D.D.N.

    2012-01-01

    Highlights: ► LAS rebars corrode 2–3 times slower than PCS in concrete pore solution and mortars. ► Raman and XRD studies show that goethite and maghemite phases of rusts formed on LAS. ► On PCS unstable phases of lepidocrocite and akaganite are formed. ► EIS confirms more stable rust on LAS than on PCS. ► A model is proposed to explain formation of passive film on surface of steels. - Abstract: Correlation of corrosion characteristics and nature of rusts on low alloy (LA) and plain carbon (PC) steels exposed in simulated concrete pore solution of different pH is studied. Rusts formed under wet/dry conditions are examined by Raman spectroscopy and X-ray diffraction. LA rust is more adherent compared to PC as confirmed by measurement of weight in gain and electrochemical studies. EIS results show improvement in protective properties of steels with passage of time. Both steels are found prone to pitting attack in chloride contaminated pore solution. Rebars embedded in concrete exhibit same trend as recorded in solution exposure tests.

  2. Low sodium diet (image)

    Science.gov (United States)

    ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ...

  3. High Antifouling Property of Ion-Selective Membrane: toward In Vivo Monitoring of pH Change in Live Brain of Rats with Membrane-Coated Carbon Fiber Electrodes.

    Science.gov (United States)

    Hao, Jie; Xiao, Tongfang; Wu, Fei; Yu, Ping; Mao, Lanqun

    2016-11-15

    In vivo monitoring of pH in live brain remains very essential to understanding acid-base chemistry in various physiological processes. This study demonstrates a potentiometric method for in vivo monitoring of pH in the central nervous system with carbon fiber-based proton-selective electrodes (CF-H + ISEs) with high antifouling property. The CF-H + ISEs are prepared by formation of a H + -selective membrane (H + ISM) with polyvinyl chloride polymeric matrixes containing plasticizer bis(2-ethylhexyl)sebacate, H + ionophore tridodecylamine, and ion exchanger potassium tetrakis(4-chlorophenyl)borate onto carbon fiber electrodes (CFEs). Both in vitro and in vivo studies demonstrate that the H + ISM exhibits strong antifouling property against proteins, which enables the CF-H + ISEs to well maintain the sensitivity and reversibility for pH sensing after in vivo measurements. Moreover, the CF-H + ISEs exhibit a good response to pH changes within a narrow physiological pH range from 6.0 to 8.0 in quick response time with high reversibility and selectivity against species endogenously existing in the central nervous system. The applicability of the CF-H + ISEs is illustrated by real-time monitoring of pH changes during acid-base disturbances, in which the brain acidosis is induced by CO 2 inhalation and brain alkalosis is induced by bicarbonate injections. The results demonstrate that brain pH value rapidly decreases in the amygdaloid nucleus by ca. 0.14 ± 0.01 (n = 5) when the rats breath in pure CO 2 gas, while increases in the cortex by about 0.77 ± 0.12 (n = 3) following intraperitoneal injection of 5 mmol/kg NaHCO 3 . This study demonstrates a new potentiometric method for in vivo measurement of pH change in the live brain of rats with high reliability.

  4. Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution-precipitation reactions in sodium carbonate solution.

    Science.gov (United States)

    Ishikawa, Kunio; Kawachi, Giichiro; Tsuru, Kanji; Yoshimoto, Ayami

    2017-03-01

    Calcium carbonate (CaCO 3 ) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6×3mm) were fabricated by compositional transformation based on dissolution-precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution-precipitation reactions, both CaSO 4 ·2H 2 O and CaSO 4 transformed into calcite, a polymorph of CaCO 3 , while maintaining their macroscopic structure when immersed in 1mol/L Na 2 CO 3 solution at 80°C for 1week. The diametral tensile strengths of the calcite blocks formed using CaSO 4 ·2H 2 O and CaSO 4 were 1.0±0.3 and 2.3±0.7MPa, respectively. The fabrication of calcite blocks using CaSO 4 ·2H 2 O and CaSO 4 proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The effect of pH on the complexation of Cd, Ni and Zn by dissolved organic carbon from leachate-polluted groundwater

    DEFF Research Database (Denmark)

    Christensen, J. B.; Christensen, Thomas Højlund

    2000-01-01

    model provided useful predictions of the complexation of Cd and Zn by DOC in the pH range 5±8, and of Ni in the pH range 5±7. At pH 8, however, the model overestimates the extent of Ni-DOC complexation to an unacceptable degree. The MINTEQA2 model predicts virtually no pH dependence for DOC complexation...

  6. The pH sensing characteristics of the extended-gate field-effect transistors of multi-walled carbon-nanotube thin film using low-temperature ultrasonic spray method.

    Science.gov (United States)

    Chien, Yun-Shan; Yang, Po-Yu; Tsai, Wan-Lin; Li, Yu-Ren; Chou, Chia-Hsin; Chou, Jung-Chuan; Cheng, Huang-Chung

    2012-07-01

    A novel, simple and low-temperature ultrasonic spray method was developed to fabricate the multi-walled carbon-nanotubes (MWCNTs) based extended-gate field-effect transistors (EGFETs) as the pH sensor. With an acid-treated process, the chemically functionalized two-dimensional MWCNT network could provide plenty of functional groups which exhibit hydrophilic property and serve as hydrogen sensing sites. For the first time, the EGFET using a MWCNT structure could achieve a wide sensing rage from pH = 1 to pH = 13. Furthermore, the pH sensitivity and linearity values of the CNT pH-EGFET devices were enhanced to 51.74 mV/pH and 0.9948 from pH = 1 to pH = 13 while the sprayed deposition reached 50 times. The sensing properties of hydrogen and hydroxyl ions show significantly dependent on the sprayed deposition times, morphologies, crystalline and chemical bonding of acid-treated MWCNT. These results demonstrate that the MWCNT-EGFETs are very promising for the applications in the pH and biomedical sensors.

  7. Foliar pH as a new plant trati: van it explain variation in foliar chemistry and carbon cycling processes among subarctiv plant species and types?

    NARCIS (Netherlands)

    Cornelissen, J.H.C.; Quested, H.M.; van Logtestijn, R.S.P; Perez-Harguindeguy, N.; Gwynn-Jones, D.; Diaz, S.; Callaghan, T.V.; Press, M.C.; Aerts, R.

    2006-01-01

    Plant traits have become popular as predictors of interspecific variation in important ecosystem properties and processes. Here we introduce foliar pH as a possible new plant trait, and tested whether (1) green leaf pH or leaf litter pH correlates with biochemical and structural foliar traits that

  8. Hidden Sodium

    Centers for Disease Control (CDC) Podcasts

    2013-03-04

    In this podcast, learn about reducing sodium intake by knowing what to eat and the main sources of sodium in the diet. It's important for a healthy lifestyle.  Created: 3/4/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/4/2013.

  9. Dietary sodium

    DEFF Research Database (Denmark)

    Graudal, Niels

    2015-01-01

    The 2013 Institute of Medicine (IOM) report "Sodium Intake in Populations: Assessment of Evidence" did not support the current recommendations of the IOM and the American Heart Association (AHA) to reduce daily dietary sodium intake to below 2,300 mg. The report concluded that the population...

  10. Subsurface pH and carbonate saturation state of aragonite on the Chinese side of the North Yellow Sea: seasonal variations and controls

    Science.gov (United States)

    Zhai, W.-D.; Zheng, N.; Huo, C.; Xu, Y.; Zhao, H.-D.; Li, Y.-W.; Zang, K.-P.; Wang, J.-Y.; Xu, X.-M.

    2014-02-01

    Based upon eight field surveys conducted between May 2011 and May 2012, we investigated seasonal variations in pH, carbonate saturation state of aragonite (Ωarag), and ancillary data on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were CO2-undersaturated in May and nearly in equilibrium with atmospheric CO2 in June. From July to October, the fugacity of CO2 (fCO2) of bottom water gradually increased from 438 ± 44 μatm to 630 ± 84 μatm, and pHT decreased from 8.02 ± 0.04 to 7.88 ± 0.06 due to local aerobic remineralization of primary-production-induced biogenic particles. The subsurface community respiration rates in summer and autumn were estimated to be from 0.80 to 1.08 μmol-O2 kg-1 d-1 within a relatively high salinity range of 31.63 to 32.25. From November to May in the next year, however, subsurface fCO2 gradually decreased and pH increased due to cooling and water column ventilation. The corresponding bottom water Ωarag was 1.85 ± 0.21 (May), 1.79 ± 0.24 (June), 1.75 ± 0.27 (July), 1.76 ± 0.29 (August), 1.45 ± 0.31 (October), 1.52 ± 0.25 (November), and 1.41 ± 0.12 (January). Extremely low Ωarag values (from 1.13 to 1.40) were observed mainly in subsurface waters within the high salinity range of 31.63 to 32.25, which covered a major fraction of the study area in October and November. Of the China seas, the North Yellow Sea represents one of the systems most vulnerable to the potential negative effects of ocean acidification.

  11. Radiolytic synthesis of carbon-supported PtRu nanoparticles using high-energy electron beam: effect of pH control on the PtRu mixing state and the methanol oxidation activity

    International Nuclear Information System (INIS)

    Ohkubo, Yuji; Kageyama, Satoru; Seino, Satoshi; Nakagawa, Takashi; Kugai, Junichiro; Nitani, Hiroaki; Ueno, Koji; Yamamoto, Takao A.

    2013-01-01

    Electrode catalysts composed of carbon-supported PtRu nanoparticles (PtRu/C) for use as a direct methanol fuel cell anode were synthesized by the reduction of precursor ions in an aqueous solution via irradiation with a high-energy electron beam. The effect of pH control in the precursor solution on the PtRu mixing state and the methanol oxidation activity was studied in order to enhance the catalytic activity for methanol oxidation. The PtRu/C structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray fluorescence spectrometry, and X-ray diffraction and X-ray absorption fine structure techniques. The methanol oxidation activity was evaluated by linear sweep voltammetry. The initial pH of the precursor solution has little influence on the average grain size for the metal particles (approximately 3.5 nm) on the carbon particle supports, but the dispersibility of the metal particles, PtRu mixing state, and methanol oxidation activity differed. The maintenance of a low pH in the precursor solution gave the best dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles, whereas, a high pH gave the best PtRu mixing state and the highest oxidation current although a low dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles was obtained. The PtRu mixing state strongly correlated with the methanol oxidation current. In addition, a high pH was more effective for PtRu mixing when using an electron beam irradiation reduction method, because the complexation reaction of the chelating agents was improved, which resulted in an enhancement of the catalytic activity for methanol oxidation.

  12. DFT investigation of NH{sub 3}, PH{sub 3}, and AsH{sub 3} adsorptions on Sc-, Ti-, V-, and Cr-doped single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Buasaeng, Prayut; Rakrai, Wandee [Computational Chemistry Center for Nanotechnology and Department of Chemistry, Faculty of Science and Technology, Rajabhat Maha Sarakham University, Maha Sarakham, 44000 (Thailand); Wanno, Banchob [Center of Excellence for Innovation in Chemistry and Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, Mahasarakham University, Maha Sarakham, 44150 (Thailand); Tabtimsai, Chanukorn, E-mail: tabtimsai.c@gmail.com [Computational Chemistry Center for Nanotechnology and Department of Chemistry, Faculty of Science and Technology, Rajabhat Maha Sarakham University, Maha Sarakham, 44000 (Thailand)

    2017-04-01

    Highlights: • Transition metal-doped single wall carbon nanotubes and their adsorption with NH{sub 3}, PH{sub 3} and AsH{sub 3} molecules were investigated using a DFT method. • Adsorptions of NH{sub 3}, PH{sub 3} and AsH{sub 3} molecules on pristine single wall carbon nanotubeswere improved by transition metal doping. • Structural and electronic properties of single wall carbon nanotubes were significantly changed by transition metal doping and gas adsorptions. - Abstract: The adsorption properties of ammonia (NH{sub 3}), phosphine (PH{sub 3}), and arsine (AsH{sub 3}) on pristine and transition metal- (TM = Sc, Ti, V, and Cr) doped (5,5) armchair single-walled carbon nanotubes (SWCNTs) were theoretically investigated. The geometric and electronic properties and adsorption abilities for the most stable configuration of NH{sub 3}, PH{sub 3}, and AsH{sub 3} adsorptions on pristine and TM-doped SWCNTs were calculated. It was found that the binding abilities of TMs to the SWCNT were in the order: Cr > V > Sc > Ti. However, the adsorption energy showed that the pristine SWCNT weakly adsorbed gas molecules and its electronic properties were also insensitive to gas molecules. By replacing a C atom with TM atoms, all doping can significantly enhance the adsorption energy of gas/SWCNT complexes and their adsorption ability was in the same order: NH{sub 3} > PH{sub 3} > AsH{sub 3}. A remarkable increase in adsorption energy and charge transfer of these systems was expected to induce significant changes in the electrical conductivity of the TM-doped SWCNTs. This work revealed that the sensitivity of SWCNT-based chemical gas adsorptions and sensors can be greatly improved by introducing an appropriate TM dopant. Accordingly, TM-doped SWCNTs are more suitable for gas molecule adsorptions and detections than the pristine SWCNT.

  13. Radiolytic synthesis of carbon-supported PtRu nanoparticles using high-energy electron beam: effect of pH control on the PtRu mixing state and the methanol oxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, Yuji, E-mail: okubo@mit.eng.osaka-u.ac.jp; Kageyama, Satoru; Seino, Satoshi; Nakagawa, Takashi; Kugai, Junichiro [Osaka University, Graduate School of Engineering (Japan); Nitani, Hiroaki [High Energy Accelerator Research Organization (KEK), Institute of Materials Structure Science (Japan); Ueno, Koji [Japan Electron Beam Irradiation Service Ltd (Japan); Yamamoto, Takao A. [Osaka University, Graduate School of Engineering (Japan)

    2013-05-15

    Electrode catalysts composed of carbon-supported PtRu nanoparticles (PtRu/C) for use as a direct methanol fuel cell anode were synthesized by the reduction of precursor ions in an aqueous solution via irradiation with a high-energy electron beam. The effect of pH control in the precursor solution on the PtRu mixing state and the methanol oxidation activity was studied in order to enhance the catalytic activity for methanol oxidation. The PtRu/C structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray fluorescence spectrometry, and X-ray diffraction and X-ray absorption fine structure techniques. The methanol oxidation activity was evaluated by linear sweep voltammetry. The initial pH of the precursor solution has little influence on the average grain size for the metal particles (approximately 3.5 nm) on the carbon particle supports, but the dispersibility of the metal particles, PtRu mixing state, and methanol oxidation activity differed. The maintenance of a low pH in the precursor solution gave the best dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles, whereas, a high pH gave the best PtRu mixing state and the highest oxidation current although a low dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles was obtained. The PtRu mixing state strongly correlated with the methanol oxidation current. In addition, a high pH was more effective for PtRu mixing when using an electron beam irradiation reduction method, because the complexation reaction of the chelating agents was improved, which resulted in an enhancement of the catalytic activity for methanol oxidation.

  14. Reactions of solid CaSO{sub 4} and Na{sub 2}CO{sub 3} and formation of sodium carbonate sulfate double salts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinsheng; Wu, Yinghai; Anthony, Edward J. [CANMET Energy Technology Centre, Natural Resources Canada, 1 Haanel Dr., Ottawa, Ontario K1A 1M1 (Canada)

    2007-07-01

    High-temperature chemical reactions in mixtures of solid CaSO{sub 4} and Na{sub 2}CO{sub 3} were investigated in order to explore the mechanisms of enhanced sulfur capture by limestones doped with Na{sub 2}CO{sub 3} in fluidized bed combustion. Drastic weight loss of the mixtures was observed in a thermogravimetric analyzer near the melting temperature of Na{sub 2}CO{sub 3}, indicating chemical reaction. X-ray diffraction analysis for a mixture of the solids following a heat treatment at 850 C revealed the existence of two sodium carbonate sulfate double salts that have not been reported before for the present system. The formation of Na{sub 2}SO{sub 4} in the melt of Na{sub 2}CO{sub 3} appears to precede the formation of the double salts. The two double salts are believed to have high porosity and specific surface area similar to those of a better-known double salt, burkeite. The implications of these findings for the enhancement of limestone sulfation by Na{sub 2}CO{sub 3} are also discussed. (author)

  15. Reactions of solid CaSO{sub 4} and Na{sub 2}CO{sub 3} and formation of sodium carbonate sulfate double salts

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jinsheng [CANMET Energy Technology Centre, Natural Resources Canada, 1 Haanel Dr., Ottawa, Ontario K1A 1M1 (Canada)]. E-mail: jiwang@nrcan.gc.ca; Wu Yinghai [CANMET Energy Technology Centre, Natural Resources Canada, 1 Haanel Dr., Ottawa, Ontario K1A 1M1 (Canada); Anthony, Edward J. [CANMET Energy Technology Centre, Natural Resources Canada, 1 Haanel Dr., Ottawa, Ontario K1A 1M1 (Canada)

    2007-07-01

    High-temperature chemical reactions in mixtures of solid CaSO{sub 4} and Na{sub 2}CO{sub 3} were investigated in order to explore the mechanisms of enhanced sulfur capture by limestones doped with Na{sub 2}CO{sub 3} in fluidized bed combustion. Drastic weight loss of the mixtures was observed in a thermogravimetric analyzer near the melting temperature of Na{sub 2}CO{sub 3}, indicating chemical reaction. X-ray diffraction analysis for a mixture of the solids following a heat treatment at 850 deg. C revealed the existence of two sodium carbonate sulfate double salts that have not been reported before for the present system. The formation of Na{sub 2}SO{sub 4} in the melt of Na{sub 2}CO{sub 3} appears to precede the formation of the double salts. The two double salts are believed to have high porosity and specific surface area similar to those of a better-known double salt, burkeite. The implications of these findings for the enhancement of limestone sulfation by Na{sub 2}CO{sub 3} are also discussed.

  16. Hydrogen generation from the hydrolysis of sodium borohydride using chemically modified multiwalled carbon nanotubes with pyridinium based ionic liquid and decorated with highly dispersed Mn nanoparticles

    Science.gov (United States)

    Chinnappan, Amutha; Puguan, John Marc C.; Chung, Wook-Jin; Kim, Hern

    2015-10-01

    Multiwalled carbon nanotubes (MWCNTs)/Ionic liquid (IL)/Mn nanohybrids are synthesized and their catalytic activity is examined for hydrogen generation from the hydrolysis of sodium borohydride (NaBH4). Transmission electron microscopy reveals that Mn nanoparticles well-distributed on the MWCNTs surface. Energy dispersive x-ray spectrometer and x-ray photoelectron spectroscopy confirms the presence of Mn and Ni atom in the nanohybrids. The nanohybrids exhibit excellent catalytic lifetime and gives the total turnover number of 18496 mol H2/mol catalyst in the hydrolysis of NaBH4, which can be attributed to the presence of Mn atom and IL containing nickel halide anion. It is worthy of note that a very small amount of catalyst is used for this hydrolysis reaction. The activation energy is found to be 40.8 kJ/mol by MWCNTs/IL/Mn nanohybrids from the kinetic study of the hydrogen generation from the hydrolysis of NaBH4. The improved hydrogen generation rate, lower activation energy, and less expensive make the nanohybrids promising candidate as catalyst for the hydrogen generation from NaBH4 solution. The nanohybrids are easy to prepare, store and yet catalytically active. The recycling process is very simple and further purification is not tedious.

  17. Selective extraction of chromium(VI) using a leaching procedure with sodium carbonate from some plant leaves, soil and sediment samples

    Energy Technology Data Exchange (ETDEWEB)

    Elci, Latif, E-mail: elci@pamukkale.edu.tr [Department of Chemistry, Pamukkale University, 20017 Denizli (Turkey); Divrikli, Umit; Akdogan, Abdullah; Hol, Aysen; Cetin, Ayse [Department of Chemistry, Pamukkale University, 20017 Denizli (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, 38039 Kayseri (Turkey)

    2010-01-15

    Speciation of chromium in some plant leaves, soil and sediment samples was carried out by selective leaching of Cr(VI) using a sodium carbonate leaching procedure. Total chromium from the samples was extracted using aqua regia and oxidative acid digestion, respectively. The concentrations of chromium species in the extracts were determined using by graphite furnace atomic absorption spectrometry (GFAAS). Uncoated graphite furnace tubes were used as an atomizer. Due to the presence of relatively high amounts of Na{sub 2}CO{sub 3} in the resulting samples, the possible influences of Na{sub 2}CO{sub 3} on the absorbance signals were checked. There is no interference of Na{sub 2}CO{sub 3} on the chromium absorbance up to 0.1 mol L{sup -1} Na{sub 2}CO{sub 3}. A limit of detection (LOD) for determination of Cr(VI) in 0.1 Na{sub 2}CO{sub 3} solution by GFAAS was found to be 0.93 {mu}g L{sup -1}. The procedure was applied to environmental samples. The relative standard deviation, R.S.D. as precision for 10 replicate measurements of 20 {mu} L{sup -1} Cr in processed soil sample was 4.2%.

  18. Selective extraction of chromium(VI) using a leaching procedure with sodium carbonate from some plant leaves, soil and sediment samples.

    Science.gov (United States)

    Elci, Latif; Divrikli, Umit; Akdogan, Abdullah; Hol, Aysen; Cetin, Ayse; Soylak, Mustafa

    2010-01-15

    Speciation of chromium in some plant leaves, soil and sediment samples was carried out by selective leaching of Cr(VI) using a sodium carbonate leaching procedure. Total chromium from the samples was extracted using aqua regia and oxidative acid digestion, respectively. The concentrations of chromium species in the extracts were determined using by graphite furnace atomic absorption spectrometry (GFAAS). Uncoated graphite furnace tubes were used as an atomizer. Due to the presence of relatively high amounts of Na(2)CO(3) in the resulting samples, the possible influences of Na(2)CO(3) on the absorbance signals were checked. There is no interference of Na(2)CO(3) on the chromium absorbance up to 0.1 mol L(-1) Na(2)CO(3). A limit of detection (LOD) for determination of Cr(VI) in 0.1 Na(2)CO(3) solution by GFAAS was found to be 0.93 microg L(-1). The procedure was applied to environmental samples. The relative standard deviation, R.S.D. as precision for 10 replicate measurements of 20 microL(-1) Cr in processed soil sample was 4.2%.

  19. Restraining Sodium Volatilization in the Ferric Bauxite Direct Reduction System

    Directory of Open Access Journals (Sweden)

    Wentao Hu

    2016-03-01

    Full Text Available Direct reduction is an emerging utilization technology of ferric bauxite. However, it requires much more sodium carbonate than ordinary bauxite does. The volatilization is one of the most significant parts of sodium carbonate consumption, as reported in previous studies. Based on the new direct reduction method for utilization of ferric bauxite, this paper has systematically investigated factors including heating temperature, heating time, and sodium carbonate dosage influencing sodium volatilization. For the purpose of reducing sodium volatilization, the Box–Benhken design was employed, and the possibility of separating iron and sodium after direct reduction was also investigated.

  20. An efficient and high-yielding one-pot synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones catalyzed by sodium hydrogen carbonate under solvent-free conditions

    OpenAIRE

    Asieh Vafaee; Abolghasem Davoodnia; Mehdi Pordel; Mohammad Reza Bozorgmehr

    2015-01-01

    Sodium hydrogen carbonate, NaHCO3, efficiently catalyzes the one-pot, three-component reaction of phthalhydrazide, an aromatic aldehyde, and malononitrile or ethyl cyanoacetate under solvent-free conditions, to afford the corresponding 1H-pyrazolo[1,2-b]phthalazine-5,10-diones in high yields. Easy work‐up, inexpensive and readily available catalyst and avoiding the use of harmful organic solvents are other advantages of this simple procedure.

  1. Composition-property relationships in multifunctional hollow mesoporous carbon nanosystems for PH-responsive magnetic resonance imaging and on-demand drug release

    Science.gov (United States)

    Zhang, Shengjian; Qian, Xiaoqing; Zhang, Linlin; Peng, Weijun; Chen, Yu

    2015-04-01

    The construction of intelligent stimuli-responsive nanosystems can substantially improve the sensitivity/resolution/specificity of diagnostic imaging and enhance the therapeutic efficiency of chemotherapy for cancer treatment. This work reports on a generic construction strategy to achieve a multiple stimuli-responsive theranostic system for cancer simply by optimizing the chemical compositions of inorganic nanoplatforms to avoid the tedious and complicated synthetic procedure for traditional organic or organic/inorganic nanosystems. Based on the ``breaking up'' nature of manganese oxides and specific features of the carbonaceous framework to interact with aromatic drug molecules, manganese oxide nanoparticles were elaborately integrated into hollow mesoporous carbon nanocapsules by a simple in situ framework redox strategy to realize concurrent pH-sensitive T1-weighted magnetic resonance imaging (MRI) and pH-/HIFU-responsive on-demand drug release. The ultrasensitive disease-triggered MRI performance has been successfully demonstrated by a 52.5-fold increase of longitudinal relaxivity (r1 = 10.5 mM-1 s-1) and on nude mice 4T1 xenograft. The pH- and HIFU-triggered doxorubicin release and enhanced therapeutic outcome against multidrug resistance of cancer cells were systematically confirmed. In particular, the fabricated inorganic composite nanocapsules were found to feature unique biological behaviours, such as antimetastasis effect, extremely low hemolysis against red blood cells and high in vivo histocompatibility. This report on the successful construction of a pure inorganic nanosystem with multiple stimuli-responsivenesses may pave the way to new methods for the development of intelligent nanofamilies for cancer therapy.The construction of intelligent stimuli-responsive nanosystems can substantially improve the sensitivity/resolution/specificity of diagnostic imaging and enhance the therapeutic efficiency of chemotherapy for cancer treatment. This work reports

  2. Impact of a sodium carbonate spray combined with professional oral hygiene procedures in patients with Sjögren's syndrome: an explorative study.

    Science.gov (United States)

    Gambino, Alessio; Broccoletti, Roberto; Cafaro, Adriana; Cabras, Marco; Carcieri, Paola; Arduino, Paolo G

    2017-06-01

    The aim of this study was to make an initial estimation on the effects of a sodium bicarbonate and xylitol spray (Cariex ® ), associated with non-surgical periodontal therapy, in participants with primary Sjögren's syndrome. Sjögren's syndrome (SS) is a multisystem autoimmune disease that predominantly involves salivary and lachrymal glands, with the clinical effect of dry eyes and mouth. A prospective cohort of 22 women and two men has been evaluated. They were randomized into three groups (eight patients each): Group A) those treated once with non-surgical periodontal therapy, education and motivation to oral hygiene, associated with the use of Cariex ® ; Group B) treated only with Cariex ® ; Group C) treated only with non-surgical periodontal therapy, education and motivation to oral hygiene. Clinical variables described after treatment were unstimulated whole salivary flow, stimulated whole salivary flow, salivary pH, reported pain (using Visual Analogue Scale) and the Periodontal Screening and Recording index. Salivary flow rate improved in all groups, but the difference was statistically significant only in those treated with Cariex ® , alone or in combination with periodontal therapy. Gingival status improved in participants who underwent periodontal non-surgical therapy while remained unchanged in those only treated with Cariex ® . Reported pain decreased in all groups, showing the best result in participants treated with periodontal therapy together with Cariex ® . We propose a practical approach for improving gingival conditions and alleviating oral symptoms in patients with SS. Future randomized and controlled trials are however required to confirm these results as well as larger population, and also assessing other parameters due to oral dryness, possible oral infections and more comprehensive periodontal indices. © 2016 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

  3. Foliar pH as a new plant trait: can it explain variation in foliar chemistry and carbon cycling processes among subarctic plant species and types?

    Science.gov (United States)

    Cornelissen, J H C; Quested, H M; van Logtestijn, R S P; Pérez-Harguindeguy, N; Gwynn-Jones, D; Díaz, S; Callaghan, T V; Press, M C; Aerts, R

    2006-03-01

    Plant traits have become popular as predictors of interspecific variation in important ecosystem properties and processes. Here we introduce foliar pH as a possible new plant trait, and tested whether (1) green leaf pH or leaf litter pH correlates with biochemical and structural foliar traits that are linked to biogeochemical cycling; (2) there is consistent variation in green leaf pH or leaf litter pH among plant types as defined by nutrient uptake mode and higher taxonomy; (3) green leaf pH can predict a significant proportion of variation in leaf digestibility among plant species and types; (4) leaf litter pH can predict a significant proportion of variation in leaf litter decomposability among plant species and types. We found some evidence in support of all four hypotheses for a wide range of species in a subarctic flora, although cryptogams (fern allies and a moss) tended to weaken the patterns by showing relatively poor leaf digestibility or litter decomposability at a given pH. Among seed plant species, green leaf pH itself explained only up to a third of the interspecific variation in leaf digestibility and leaf litter up to a quarter of the interspecific variation in leaf litter decomposability. However, foliar pH substantially improved the power of foliar lignin and/or cellulose concentrations as predictors of these processes when added to regression models as a second variable. When species were aggregated into plant types as defined by higher taxonomy and nutrient uptake mode, green-specific leaf area was a more powerful predictor of digestibility or decomposability than any of the biochemical traits including pH. The usefulness of foliar pH as a new predictive trait, whether or not in combination with other traits, remains to be tested across more plant species, types and biomes, and also in relation to other plant or ecosystem traits and processes.

  4. 2D ratiometric fluorescent pH sensor for tracking of cells proliferation and metabolism.

    Science.gov (United States)

    Ma, Jun; Ding, Changqin; Zhou, Jie; Tian, Yang

    2015-08-15

    Extracellular pH plays a vital role no matter in physiological or pathological studies. In this work, a hydrogel, CD@Nile-FITC@Gel (Gel sensor), entrapping the ratiometric fluorescent probe CD@Nile-FITC was developed. The Gel sensor was successfully used for real-time extracellular pH monitoring. In the case of CD@Nile-FITC, pH-sensitive fluorescent dye fluorescein isothiocyanate (FITC) was chosen as the response signal for H(+) and Nile blue chloride (Nile) as the reference signal. The developed fluorescent probe exhibited high selectivity for pH over other metal ions and amino acids. Meanwhile, the carbon-dots-based inorganic-organic probe demonstrated excellent photostability against long-term light illumination. In order to study the extracellular pH change in processes of cell proliferation and metabolism, CD@Nile-FITC probe was entrapped in sodium alginate gel and consequently formed CD@Nile-FITC@Gel. The MTT assay showed low cytotoxicity of the Gel and the pH titration indicated that it could monitor the pH fluctuations linearly and rapidly within the pH range of 6.0-9.0, which is valuable for physiological pH determination. As expected, the real-time bioimaging of the probe was successfully achieved. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Sodium Oxybate

    Science.gov (United States)

    ... or give your sodium oxybate to anyone else; selling or sharing it is against the law. Store ... dehydrogenase deficiency (an inherited condition in which certain substances build up in the body and cause retardation ...

  6. Sodium Azide

    Science.gov (United States)

    ... Exposure to a large amount of sodium azide by any route may cause these other health effects as well: Convulsions Low blood pressure Loss of consciousness Lung injury Respiratory failure leading to death Slow heart rate ...

  7. The various sodium purification techniques

    International Nuclear Information System (INIS)

    Courouau, J.L.; Masse, F.; Rodriguez, G.; Latge, C.; Redon, B.

    1997-01-01

    In the framework of sodium waste treatment, the sodium purification phase plays an essential role in the chain of operations leading to the transformation of the active sodium, considered as waste, into a stable sodium salt. The objectives of the purification operations are: To keep a low impurity level, particularly a low concentration in oxygen and hydrogen, in order to allow its transfer to a processing plant, and in order to avoid risks of plugging and/or corrosion in sodium facilities; To reduce the sodium activity in order to limit the dose rate close to the facilities, and in order to reduce the activity of the liquid and gaseous effluents. After a recall of the different kind of impurities that can be present in sodium, and of the different purification methods that could be associated with, the following points are highlighted: (i) Oxygen and hydrogen purification needs, and presentation of some selection criteria for a purification unit adapted to a sodium processing plant, as well as 2 cold trap concepts that are in accordance with these criteria: PSICHOS and PIRAMIDE. (ii) Tritium reduction in a bulk of liquid sodium by swamping, isotopic exchange, or permeation throughout a membrane. (iii) Caesium trapping on carbonaceous matrix. The main matrices used at present are R.V.C. (Reticulated Vitreous Carbon) and Actitex/Pica products. Tests in the laboratory and on an experimental device have demonstrated the performances of these materials, which are able to reduce sodium activity in Cs 134 and Cs 137 to very low values. The sodium purification processes as regards to the hydrogen, oxygen and caesium, that are aimed at facilitating the subsequent treatment of sodium, are therefore mastered operations. Regarding the operations associated with the reduction of the tritium activity, the methods are in the process of being qualified, or to be qualified. (author)

  8. Sodium sampling and impurities determination

    International Nuclear Information System (INIS)

    Docekal, J.; Kovar, C.; St