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Sample records for acetic acid-catalyzed hydrothermal

  1. Recovery of arabinan in acetic acid-catalyzed hydrothermal pretreatment on corn stover

    DEFF Research Database (Denmark)

    Xu, Jian; Hedegaard, Mette Christina; Thomsen, Anne Belinda

    2009-01-01

    Acetic acid-catalyzed hydrothermal pretreatment was done on corn stover under 195 °C, 15 min with the acetic acid ranging from 5 × 10−3 to 0.2 g g−1 corn stover. After pretreatment, the water-insoluble solids (WISs) and liquors were collected respectively. Arabinan recoveries from both WIS...

  2. Investigation of acetic acid-catalyzed hydrothermal pretreatment on corn stover

    DEFF Research Database (Denmark)

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2010-01-01

    Acetic acid (AA)-catalyzed liquid hot water (LHW) pretreatments on raw corn stover (RCS) were carried out at 195 °C at 15 min with the acetic acid concentrations between 0 and 400 g/kg RCS. After pretreatment, the liquor fractions and water-insoluble solids (WIS) were collected separately and tes...

  3. Acetic acid-catalyzed hydrothermal pretreatment of corn stover for the production of bioethanol at high-solids content.

    Science.gov (United States)

    Katsimpouras, Constantinos; Christakopoulos, Paul; Topakas, Evangelos

    2016-09-01

    Corn stover (CS) was hydrothermally pretreated using CH3COOH (0.3 %, v/v), and subsequently its ability to be utilized for conversion to ethanol at high-solids content was investigated. Pretreatment conditions were optimized employing a response surface methodology (RSM) with temperature and duration as independent variables. Pretreated CS underwent a liquefaction/saccharification step at a custom designed free-fall mixer at 50 °C for either 12 or 24 h using an enzyme loading of 9 mg/g dry matter (DM) at 24 % (w/w) DM. Simultaneous enzymatic saccharification and fermentation (SSF) of liquefacted corn stover resulted in high ethanol concentration (up to 36.8 g/L), with liquefaction duration having a negligible effect. The threshold of ethanol concentration of 4 % (w/w), which is required to reduce the cost of ethanol distillation, was surpassed by the addition of extra enzymes at the start up of SSF achieving this way ethanol titer of 41.5 g/L.

  4. Acetic acid-catalyzed formation of N-phenylphthalimide from phthalanilic acid: a computational study of the mechanism.

    Science.gov (United States)

    Takahashi, Ohgi; Kirikoshi, Ryota; Manabe, Noriyoshi

    2015-05-28

    In glacial acetic acid, phthalanilic acid and its monosubstituents are known to be converted to the corresponding phthalimides in relatively good yields. In this study, we computationally investigated the experimentally proposed two-step (addition-elimination or cyclization-dehydration) mechanism at the second-order Møller-Plesset perturbation (MP2) level of theory for the unsubstituted phthalanilic acid, with an explicit acetic acid molecule included in the calculations. In the first step, a gem-diol tetrahedral intermediate is formed by the nucleophilic attack of the amide nitrogen. The second step is dehydration of the intermediate to give N-phenylphthalimide. In agreement with experimental findings, the second step has been shown to be rate-determining. Most importantly, both of the steps are catalyzed by an acetic acid molecule, which acts both as proton donor and acceptor. The present findings, along with those from our previous studies, suggest that acetic acid and other carboxylic acids (in their undissociated forms) can catalyze intramolecular nucleophilic attacks by amide nitrogens and breakdown of the resulting tetrahedral intermediates, acting simultaneously as proton donor and acceptor. In other words, double proton transfers involving a carboxylic acid molecule can be part of an extensive bond reorganization process from cyclic hydrogen-bonded complexes.

  5. Additive effects of acetic acid upon hydrothermal reaction of amylopectin

    International Nuclear Information System (INIS)

    Sugano, Motoyuki; Katoh, Harumi; Komatsu, Akihiro; Kobayashi, Hiroshi; Okado, Kohta; Kakuta, Yusuke; Hirano, Katsumi

    2012-01-01

    It is well known that over 0.8 kg kg −1 of starch is consisted of amylopectin (AP). In this study, production of glucose for raw material of ethanol by hydrothermal reaction of AP as one of the model compound of food is discussed. Further, additive effects of acetic acid upon hydrothermal reactions of AP are also investigated. During hydrothermal reaction of AP, production of glucose occurred above 453 K, and the glucose yield increased to 0.48 kg kg −1 at 473 K. Upon hydrothermal reaction of AP at 473 K, prolongation of the holding time was not effective for the increase of the glucose yield. Upon hydrothermal reaction of AP at 473 K for 0 s, the glucose yield increased significantly by addition between 0.26 mol L −1 and 0.52 mol L −1 of acetic acid. However, the glucose yield decreased and the yield of the other constituents increased with the increases of concentration of acetic acid from 0.65 mol L −1 to 3.33 mol L −1 . It was considered that hydrolysis of AP to yield glucose was enhanced due to the increase of the amount of proton derived from acetic acid during hydrothermal reaction with 0.52 mol L −1 of acetic acid. -- Highlights: ► Glucose production by hydrothermal reaction of amylopectin (AP) at 473 K. ► Glucose yield increased to 0.48 kg kg -1 at 473 K. ► Prolongation of holding time was not effective for glucose yield. ► Glucose yield increased significantly by acetic acid (0.26–0.52 mol L-1) addition. ► Hydrolysis of AP to glucose was enhanced due to increase of proton from acetic acid.

  6. Investigation of the Characteristic Properties of Glacial Acetic Acid-Catalyzed Carbon Xerogels and Their Electrochemical Performance for Use as Electrode Materials in Electrical Double-Layer Capacitors

    Directory of Open Access Journals (Sweden)

    Nguyen Khanh Nguyen Quach

    2017-01-01

    Full Text Available Glacial acetic acid was used as a catalyst in the preparation process of carbon xerogels from the condensation of resorcinol and formaldehyde for shortening significantly the gelation time. The effect of the resorcinol/catalyst ratio over a large range of 2 to 500, the solvent exchange manner with acetone, and the pyrolysis temperature of 700 to 1000°C on the characteristic properties of the carbon xerogels were investigated. A resorcinol/catalyst ratio of 2 and a pyrolysis temperature at 800°C were found to be the optimal condition for the preparation of carbon xerogels with a well-balanced porosity between micro- and mesopores, high surface area (577.62 m2g−1, and large pore volume (0.97 cm3g−1, which are appropriate for use as electrode materials in an electrical double-layer capacitor. The carbon xerogel electrodes that were prepared under these optimal conditions exhibited a good electrochemical performance with the highest specific capacitance of 169 Fg−1 in 6 M KOH electrolyte at a scan rate of 5 mVs−1 from cyclic voltammetry.

  7. Identification and activity of acetate-assimilating bacteria in diffuse fluids venting from two deep-sea hydrothermal systems.

    Science.gov (United States)

    Winkel, Matthias; Pjevac, Petra; Kleiner, Manuel; Littmann, Sten; Meyerdierks, Anke; Amann, Rudolf; Mußmann, Marc

    2014-12-01

    Diffuse hydrothermal fluids often contain organic compounds such as hydrocarbons, lipids, and organic acids. Microorganisms consuming these compounds at hydrothermal sites are so far only known from cultivation-dependent studies. To identify potential heterotrophs without prior cultivation, we combined microbial community analysis with short-term incubations using (13)C-labeled acetate at two distinct hydrothermal systems. We followed cell growth and assimilation of (13)C into single cells by nanoSIMS combined with fluorescence in situ hybridization (FISH). In 55 °C-fluids from the Menez Gwen hydrothermal system/Mid-Atlantic Ridge, a novel epsilonproteobacterial group accounted for nearly all assimilation of acetate, representing the first aerobic acetate-consuming member of the Nautiliales. In contrast, Gammaproteobacteria dominated the (13) C-acetate assimilation in incubations of 37 °C-fluids from the back-arc hydrothermal system in the Manus Basin/Papua New Guinea. Here, 16S rRNA gene sequences were mostly related to mesophilic Marinobacter, reflecting the high content of seawater in these fluids. The rapid growth of microorganisms upon acetate addition suggests that acetate consumers in diffuse fluids are copiotrophic opportunists, which quickly exploit their energy sources, whenever available under the spatially and temporally highly fluctuating conditions. Our data provide first insights into the heterotrophic microbial community, catalyzing an under-investigated part of microbial carbon cycling at hydrothermal vents. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  8. DFT Investigation of the Diastereoselectivity of the MX2and MX3Lewis-Acid-Catalyzed Mukaiyama Aldol Reaction between C,O,O-Tris(trimethylsilyl)ketene Acetal and Aldehydes.

    Science.gov (United States)

    Mohamed, Slim Hadj; Champagne, Benoît; Trabelsi, Mahmoud

    2018-03-01

    The kinetics and diastereoselectivity of the Mukaiyama aldol reaction between C,O,O-tris(trimethylsilyl)ketene acetal and aldehydes bearing alkyl, vinyl, and aromatic substituents is influenced by the nature of Lewis acid catalysts. A density functional theory investigation using the M06-2X exchange-correlation functional and the PCM scheme to account for solvent effects has been carried out to characterize the structure and energetics of the transition state when the Lewis acid is ZnBr 2 (MX 2 ) or GaCl 3 (MX 3 ) in comparison to the uncatalyzed reaction. The main observations are that (i) the pro-syn transition states are always more stable than the pro-anti ones; (ii) for MX 2 , the transition state presents a cyclic structure, whereas it is open for MX 3 , owing to steric interactions; (iii) the difference of activation free enthalpy between the pro-anti and pro-syn transition states decreases when the reaction is catalyzed, by either MX 2 or MX 3 , demonstrating a reduction of the diastereoselectivity with respect to the uncatalyzed reaction; (iv) this decrease of diastereoselectivity is larger for MX 3 - than for MX 2 -catalyzed reactions; and (v) the MX 3 -catalyzed reactions are kinetically favored by 1-2 kcal mol -1 with respect to the MX 2 ones.

  9. Preparation of MnO nanofibers by novel hydrothermal treatment of manganese acetate/PVA electrospun nanofiber mats

    International Nuclear Information System (INIS)

    Barakat, Nasser A.M.; Park, Soo Jin; Khil, Myung Seob; Kim, Hak Yong

    2009-01-01

    In the present study, manganese monoxide (MnO) which is hard to prepare because of the chemical activity of the manganese metal has been synthesized in nanofibrous form. An electrospun manganese acetate/poly(vinyl alcohol) nanofiber mats have been hydrothermally treated by novel strategy. The treatment process was based on producing of water gas (Co and H 2 ) to eliminate the polymer and reduced the manganese acetate to manganese monoxide. The process was carried out by heating the dried nanofiber mates at 400 deg. C for 3 h in an especial designed reactor in which a stream of water vapor was passing through a bed of an activated carbon. The obtained physiochemical characterization results indicated that the proposed hydrothermal treatment process does have the ability to produce pure MnO nanofibers with good crystallinity.

  10. Production of acetic acid by hydrothermal two-step process of vegetable wastes for use as a road deicer

    Energy Technology Data Exchange (ETDEWEB)

    Jin, F; Watanabe, Y; Kishita, A; Enomoto, H [Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579 (Japan); Kishida, H [Environmental Systems Headquarters, Environmental Research and Development Center Hitachi Zosen Corporation, Kyoto 625-8501 (Japan)], E-mail: fmjin@mail.tongji.edu.cn

    2008-07-15

    This study aimed to produce acetic acid from vegetable wastes by a new hydrothermal two-step process. A continuous flow reaction system with a maximum treatment capacity of 2 kg/h of dry biomass developed by us was used. Five kinds of vegetables of carrots, white radish, chinese cabbage, cabbage and potato were selected as the representation of vegetable wastes. First, batch experiments with the selected vegetables were performed under the condition of 300 deg. C, 1 min for the first step, and 300 deg. C, 1 min and 70% oxygen supply for the second step, which is the optimum condition for producing acetic acid in the case of using starch as test material. The highest yields of acetic acid from five vegetables were almost the same as those obtained from starch. Subsequently, similar the highest yield of acetic acid and experimental conditions from vegetables were also obtained successfully using the continuous flow reaction system. These results should be useful for developing an industrial scale process.

  11. Selective Oxidation of 1,2-Propanediol to Carboxylic Acids Catalyzed by Copper Nanoparticles.

    Science.gov (United States)

    Xue, Wuping; Yin, Hengbo; Lu, Zhipeng; Wang, Aili; Liu, Shuxin; Shen, Lingqin

    2018-05-01

    Copper nanoparticles with different particle sizes were prepared by a wet chemical reduction method in the presence of organic modifiers, such as citric acid (CA), hexadecyl trimethyl ammonium bromide, Tween-80 (Tween), and polyethylene glycol 6000. Selective oxidation of sustainable 1,2-propanediol with O2 to high-valued lactic, formic, and acetic acids catalyzed by the copper nanoparticles in an alkaline medium was investigated. The small-sized CuCA nanoparticles with the average particle size of 15.2 nm favored the formation of acetic and formic acids while the CuTween nanoparticles with the average particle size of 26.9 nm were beneficial to the formation of lactic acid. The size effect of copper nanoparticles on the catalytic oxidation of 1,2-propanediol to the carboxylic acids was obvious.

  12. preparation of bicyclic lactones using lewis acids catalyzed ene

    African Journals Online (AJOL)

    Administrator

    LEWIS ACIDS CATALYZED ENE-REACTION. MAKAMA, B. Y.. Department of Petroleum Chemistry, ... the Lewis acid catalysed carbonyl-ene reaction which has been widely used to access carbocycles. In 1943 ..... Alkylaluminum halide induced cyclization of unsaturated carbonyl compounds. Journal of Organic Chemistry.

  13. Acid-catalyzed cyclization of cembrene and isocembrol

    Energy Technology Data Exchange (ETDEWEB)

    Dauben, W.G.; Hubbell, J.P.; Oberhansli, P.; Thiessen, W.E.

    1979-03-02

    The acid-catalyzed ring closure of cembrene, a 14-membered ring diterpene, and its derivatives have been studied. The predominant reaction pathway yields a hydrophenanthrene ring system. Under mild conditions isomeric tricyclic compounds are formed, but under more forcing conditions aromatization of a ring occurs. The detailed mechanisms of these reaction processes have been evaluated. 1 figure, 3 tables.

  14. 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.

  15. Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Dral, Albertine Petra

    2016-01-01

    Supported microporous organosilica membranes made from bridged silsesquioxane precursors by an acid-catalyzed sol–gel process have demonstrated a remarkable hydrothermal stability in pervaporation and gas separation processes, making them the first generation of ceramic molecular sieving membranes

  16. Kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2007-01-01

    A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is

  17. Template-assisted hydrothermally synthesized iron-titanium binary oxides and their application as catalysts for ethyl acetate oxidation

    Czech Academy of Sciences Publication Activity Database

    Tsoncheva, T.; Ivanova, R.; Dimitrov, M.; Paneva, D.; Kovacheva, D.; Henych, Jiří; Vomáčka, Petr; Kormunda, M.; Velinov, N.; Mitov, I.; Štengl, Václav

    2016-01-01

    Roč. 528, NOV (2016), s. 24-35 ISSN 0926-860X R&D Projects: GA MŠk(CZ) LM2015073 Institutional support: RVO:61388980 Keywords : Effect of Fe/Ti ratio and temperature of hydrothermal treatment * Hydrothermal synthesis * Iron-titanium binary oxides Subject RIV: CA - Inorganic Chemistry Impact factor: 4.339, year: 2016

  18. Template-assisted hydrothermally obtained titania-ceria composites and their application as catalysts in ethyl acetate oxidation and methanol decomposition with a potential for sustainable environment protection

    Czech Academy of Sciences Publication Activity Database

    Tsoncheva, T.; Mileva, A.; Issa, G.; Dimitrov, M.; Kovacheva, D.; Henych, Jiří; Scotti, N.; Kormunda, M.; Atanasova, G.; Štengl, Václav

    2017-01-01

    Roč. 396, FEB (2017), s. 1289-1302 ISSN 0169-4332 R&D Projects: GA MŠk(CZ) LM2015073 Grant - others:AV ČR(CZ) BAS-17-13 Program:Bilaterální spolupráce Institutional support: RVO:61388980 Keywords : Ceria-titania binary oxides * Template assisted hydrothermal synthesis * Methanol decomposition * Ethyl acetate oxidation Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 3.387, year: 2016

  19. Acid-catalyzed production of biodiesel from waste frying oil

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, S.; Dube, M.A.; McLean, D.D. [Department of Chemical Engineering, University of Ottawa, Ottawa, ON (Canada); Kates, M. [Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON (Canada)

    2006-03-15

    The reaction kinetics of acid-catalyzed transesterification of waste frying oil in excess methanol to form fatty acid methyl esters (FAME), for possible use as biodiesel, was studied. Rate of mixing, feed composition (molar ratio oil:methanol:acid) and temperature were independent variables. There was no significant difference in the yield of FAME when the rate of mixing was in the turbulent range 100 to 600rpm. The oil:methanol:acid molar ratios and the temperature were the most significant factors affecting the yield of FAME. At 70{sup o}C with oil:methanol:acid molar ratios of 1:245:3.8, and at 80{sup o}C with oil:methanol:acid molar ratios in the range 1:74:1.9-1:245:3.8, the transesterification was essentially a pseudo-first-order reaction as a result of the large excess of methanol which drove the reaction to completion (99+/-1% at 4h). In the presence of the large excess of methanol, free fatty acids present in the waste oil were very rapidly converted to methyl esters in the first few minutes under the above conditions. Little or no monoglycerides were detected during the course of the reaction, and diglycerides present in the initial waste oil were rapidly converted to FAME. (author)

  20. Sodium acetate assisted hydrothermal growth of dumbbell-like β -NaGdF4 nanobundles: Morphology control and products transformation

    Science.gov (United States)

    Wu, Kelu; Wang, Yi-Yan; Xia, Tian-Long

    2017-08-01

    Hierarchical β -NaGdF4 nanobundles are synthesized through a facile hydrothermal method with the use of sodium acetate (NaAc). A NaGdF4-GdF3-NaGdF4 products transformation with the increase of fluoride source (NaF) is observed. Results show that NaAc is the key factor in the synthesis of β -NaGdF4 at a low NaF/Gd3+ ratio and NaAc also plays a significant role in the formation of the hierarchical morphology. Meanwhile, the size of nanobundles increases with the increased ratio of NaF/NaAc. With altering the ratio of reactants, dumbbell-like, urchin-like or rod-like β -NaGdF4 nanobundles are obtained. The photoluminescent properties of β -NaGdF4: 2%Eu3+ are also measured.

  1. Acetic acid recovery from a hybrid biological-hydrothermal treatment process of sewage sludge - a pilot plant study.

    Science.gov (United States)

    Andrews, J; Dare, P; Estcourt, G; Gapes, D; Lei, R; McDonald, B; Wijaya, N

    2015-01-01

    A two-stage process consisting of anaerobic fermentation followed by sub-critical wet oxidation was used to generate acetic acid from sewage sludge at pilot scale. Volatile fatty acids, dominated by propionic acid, were produced over 4-6 days in the 2,000 L fermentation reactor, which also achieved 31% solids reduction. Approximately 96% of the carbon was retained in solution over the fermentation stage. Using a 200 L wet oxidation reactor operating in batch mode, the second stage achieved 98% volatile suspended solids (VSS) destruction and 67% total chemical oxygen demand (tCOD) destruction. Acetic acid produced in this stage was recalcitrant to further degradation and was retained in solution. The gross yield from VSS was 16% for acetic acid and 21% for volatile fatty acids across the process, higher than reported yields for wet oxidation alone. The pilot plant results showed that 72% of the incoming phosphorus was retained in the solids, 94% of the nitrogen became concentrated in solution and 41% of the carbon was converted to a soluble state, in a more degradable form. Acetic acid produced from the process has the potential to be used to offset ethanol requirements in biological nutrient removal plants.

  2. Pretreatment of corn stover with diluted acetic acid for enhancement of acidogenic fermentation.

    Science.gov (United States)

    Zhao, Xu; Wang, Lijuan; Lu, Xuebin; Zhang, Shuting

    2014-04-01

    A Box-Behnken design of response surface method was used to optimize acetic acid-catalyzed hydrothermal pretreatment of corn stover, in respect to acid concentration (0.05-0.25%), treatment time (5-15 min) and reaction temperature (180-210°C). Acidogenic fermentations with different initial pH and hydrolyzates were also measured to evaluate the optimal pretreatment conditions for maximizing acid production. The results showed that pretreatment with 0.25% acetic acid at 191°C for 7.74 min was found to be the most optimal condition for pretreatment of corn stover under which the production of acids can reach the highest level. Acidogenic fermentation with the hydrolyzate of pretreatment at the optimal condition at the initial pH=5 was shown to be butyric acid type fermentation, producing 21.84 g acetic acid, 7.246 g propionic acid, 9.170 butyric acid and 1.035 g isovaleric acid from 100g of corn stover in 900 g of water containing 2.25 g acetic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Acid-Catalyzed Preparation of Biodiesel from Waste Vegetable Oil: An Experiment for the Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Bladt, Don; Murray, Steve; Gitch, Brittany; Trout, Haylee; Liberko, Charles

    2011-01-01

    This undergraduate organic laboratory exercise involves the sulfuric acid-catalyzed conversion of waste vegetable oil into biodiesel. The acid-catalyzed method, although inherently slower than the base-catalyzed methods, does not suffer from the loss of product or the creation of emulsion producing soap that plagues the base-catalyzed methods when…

  4. Solid Acid-Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR-IR Spectroscopy

    NARCIS (Netherlands)

    Zakzeski, J.; Grisel, R.J.H.; Smit, A.T.; Weckhuysen, B.M.

    2012-01-01

    The solid acid-catalyzed hydrolysis of cellulose was studied under elevated temperatures and autogenous pressures using in situ ATR-IR spectroscopy. Standards of cellulose and pure reaction products, which include glucose, fructose, hydroxymethylfurfural (HMF), levulinic acid (LA), formic acid, and

  5. An enantioselective Brønsted acid catalyzed enamine Mannich reaction.

    Science.gov (United States)

    Tillman, A Louise; Dixon, Darren J

    2007-02-21

    An enantioselective Brønsted acid catalyzed Mannich reaction between acetophenone derived enamines and N-Boc imines has been developed. Simple diol (S)-H(8)-BINOL has been identified as the optimal catalyst, to afford versatile beta-amino aryl ketones in good yield and enantiomeric excess.

  6. A green non-acid-catalyzed process for direct N=N-C group formation: comprehensive study, modeling, and optimization.

    Science.gov (United States)

    Khakyzadeh, Vahid; Zolfigol, Mohammad Ali; Derakhshan-Panah, Fatemeh; Jafarian, Majid; Miri, Mir Vahid; Gilandoust, Maryam

    2018-01-04

    The aim of this work is to introduce, model, and optimize a new non-acid-catalyzed system for a direct N[Formula: see text]N-C bond formation. By reacting naphthols or phenol with anilines in the presence of the sodium nitrite as nitrosonium ([Formula: see text] source and triethylammonium acetate (TEAA), a N[Formula: see text]N-C group can be formed in non-acid media. Modeling and optimization of the reaction conditions were investigated by response surface method. Sodium nitrite, TEAA, and water were chosen as variables, and reaction yield was also monitored. Analysis of variance indicates that a second-order polynomial model with F value of 35.7, a P value of 0.0001, and regression coefficient of 0.93 is able to predict the response. Based on the model, the optimum process conditions were introduced as 2.2 mmol sodium nitrite, 2.2 mL of TEAA, and 0.5 mL [Formula: see text] at room temperature. A quadratic (second-order) polynomial model, by analysis of variance, was able to predict the response for a direct N=N-C group formation. Predicted response values were in good agreement with the experimental values. Electrochemistry studies were done to introduce new Michael acceptor moieties. Broad scope, high yields, short reaction time, and mild conditions are some advantages of the presented method.

  7. Elucidating Latent Mechanistic Complexity in Competing Acid-Catalyzed Reactions of Salicylaldehyde-Derived Baylis-Hillman Adducts.

    Science.gov (United States)

    Olomola, Temitope O; Klein, Rosalyn; Caira, Mino R; Kaye, Perry T

    2016-01-04

    (1)H NMR-based kinetic studies have revealed the latent mechanistic complexity of deceptively simple hydrochloric acid-catalyzed reactions of salicylaldehyde-derived Baylis-Hillman adducts. Reactions conducted at 0 °C afforded 2-(chloromethyl)cinnamic acid derivatives as the major products and the corresponding 3-(chloromethyl)coumarin derivatives as the minor products. In reactions conducted in refluxing acetic acid, however, the 3-(chloromethyl)coumarin derivatives are the sole products. Variable-temperature (1)H NMR analysis permitted the determination of the rate constants and kinetic parameters involved in the pseudo-first-order formation of (Z)-2-(chloromethyl)-3-(2-hydroxyphenyl)-2-propenoic acid. The kinetic data clearly preclude the operation of classical kinetic versus thermodynamic control and indicate the operation of three independent reaction pathways. Theoretical studies of these pathways undertaken at the B3LYP/6-31G(d) level permitted rationalization of the experimental data and provided insights into the possible mechanism of the enzymic E-Z isomerization and cyclization of (E)-cinnamic acid analogues to afford coumarins.

  8. On the Brønsted acid-catalyzed homogeneous hydrolysis of furans.

    Science.gov (United States)

    Nikbin, Nima; Caratzoulas, Stavros; Vlachos, Dionisios G

    2013-11-01

    Furan affairs: Electronic structure calculations of the homogeneous Brønsted acid-catalyzed hydrolysis of 2,5-dimethylfuran show that proton transfer to the β-position is rate-limiting and provides support that the hydrolysis follows general acid catalysis. By means of projected Fukui indices, we show this to be the case for unsubstituted, 2-, and 2,5-substituted furans with electron-donating groups. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Variables affecting the reactivity of acid-catalyzed transesterification of vegetable oil with methanol.

    Science.gov (United States)

    Furukawa, Shigeki; Uehara, Yoshihiro; Yamasaki, Hiroshi

    2010-05-01

    The dominant factors affecting the reactivity of acid-catalyzed transesterification of vegetable oil with methanol have been investigated. Effects of varying the acid catalyst species, surface active agent type and content were studied. Also, the effect of the type of oil was examined. Biodiesel fuel yields increased with the addition of sodium dodecylsulfonate as surface active agent because the mass transfer rates of protons and methanol to the oil phase through the oil-methanol interface were increased with increasing interfacial area. Evaluation of the reaction kinetics, based on changes in parent oils containing triglyceride or diglyceride showed that the activation energies were almost no change, but the frequency factors were 2210 and 9827mol(-1)min(-1), respectively. Therefore, it was concluded that a lower reactivity during acid-catalyzed transesterification with methanol was caused by a lower contact probability for oil, methanol and acid catalyst in the presence of an oil-methanol interface during the reaction. Copyright 2009 Elsevier Ltd. All rights reserved.

  10. Integrated Production of Xylonic Acid and Bioethanol from Acid-Catalyzed Steam-Exploded Corn Stover.

    Science.gov (United States)

    Zhu, Junjun; Rong, Yayun; Yang, Jinlong; Zhou, Xin; Xu, Yong; Zhang, Lingling; Chen, Jiahui; Yong, Qiang; Yu, Shiyuan

    2015-07-01

    High-efficiency xylose utilization is one of the restrictive factors of bioethanol industrialization. However, xylonic acid (XA) as a new bio-based platform chemical can be produced by oxidation of xylose with microbial. So, an applicable technology of XA bioconversion was integrated into the process of bioethanol production. After corn stover was pretreated with acid-catalyzed steam-explosion, solid and liquid fractions were obtained. The liquid fraction, also named as acid-catalyzed steam-exploded corn stover (ASC) prehydrolyzate (mainly containing xylose), was catalyzed with Gluconobacter oxydans NL71 to prepare XA. After 72 h of bioconversion of concentrated ASC prehydrolyzate (containing 55.0 g/L of xylose), the XA concentration reached a peak value of 54.97 g/L, the sugar utilization ratio and XA yield were 94.08 and 95.45 %, respectively. The solid fraction was hydrolyzed to produce glucose with cellulase and then fermented with Saccharomyces cerevisiae NL22 to produce ethanol. After 18 h of fermentation of concentrated enzymatic hydrolyzate (containing 86.22 g/L of glucose), the ethanol concentration reached its highest value of 41.48 g/L, the sugar utilization ratio and ethanol yield were 98.72 and 95.25 %, respectively. The mass balance showed that 1 t ethanol and 1.3 t XA were produced from 7.8 t oven dry corn stover.

  11. Sulfuric, hydrochloric, and nitric acid-catalyzed triacetone triperoxide (TATP) reaction mixtures: an aging study.

    Science.gov (United States)

    Fitzgerald, Mark; Bilusich, Daniel

    2011-09-01

    The organic peroxide explosive triacetone triperoxide (TATP) is regularly encountered by law enforcement agents in various stages of its production. This study utilizes solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) to examine sulfuric acid-, hydrochloric acid-, and nitric acid-catalyzed TATP syntheses during the initial 24 h of these reactions at low temperatures (5-9°C). Additionally, aging of the reaction mixtures was examined at both low and ambient temperatures (19-21°C) for a further 9 days. For each experiment, TATP could be readily identified in the headspace above the reaction mixture 1 h subsequent to the combination of reagents; at 24 h, TATP and diacetone diperoxide (DADP) were prominent. TATP degraded more rapidly than DADP. Additionally, chlorinated acetones chloroacetone and 1,1,-dichloroacetone were identified in the headspace above the hydrochloric acid-catalyzed TATP reaction mixture. These were not present when the catalyst was sulfuric acid or nitric acid. 2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.

  12. Solid acid-catalyzed depolymerization of barley straw driven by ball milling.

    Science.gov (United States)

    Schneider, Laura; Haverinen, Jasmiina; Jaakkola, Mari; Lassi, Ulla

    2016-04-01

    This study describes a time and energy saving, solvent-free procedure for the conversion of lignocellulosic barley straw into reducing sugars by mechanocatalytical pretreatment. The catalytic conversion efficiency of several solid acids was tested which revealed oxalic acid dihydrate as a potential catalyst with high conversion rate. Samples were mechanically treated by ball milling and subsequently hydrolyzed at different temperatures. The parameters of the mechanical treatment were optimized in order to obtain sufficient amount of total reducing sugar (TRS) which was determined following the DNS assay. Additionally, capillary electrophoresis (CE) and Fourier transform infrared spectrometry (FT-IR) were carried out. Under optimal conditions TRS 42% was released using oxalic acid dihydrate as a catalyst. This study revealed that the acid strength plays an important role in the depolymerization of barley straw and in addition, showed, that the oxalic acid-catalyzed reaction generates low level of the degradation product 5-hydroxymethylfurfural (HMF). Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Oxidation Chemistry and Kinetics of Model Compounds in Supercritical Water: Glucose, Acetic Acid, and Methylene Chloride

    Science.gov (United States)

    1993-06-01

    its destruction I I Objectives , 27 3 via SCWO in heterogeneous mixtures such as a soil slurry or in co-oxidation studies. Characterization of the...94, 199. I Frisch, M.A. (1992) ’Supercritical water oxidation of acetic acid catalyzed by CeO2 /MnO2.* Masters Thesis, The University of Texas

  14. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    2012-01-01

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed that th...

  15. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    2012-01-01

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed...

  16. Revised Theoretical Model on Enantiocontrol in Phosphoric Acid Catalyzed H-Transfer Hydrogenation of Quinoline.

    Science.gov (United States)

    Pastor, Julien; Rezabal, Elixabete; Voituriez, Arnaud; Betzer, Jean-François; Marinetti, Angela; Frison, Gilles

    2018-03-02

    The enantioselective H-transfer hydrogenation of quinoline by Hantzsch ester is a relevant example of Brønsted acid catalyzed cascade reactions, with phosphoric acid being a privileged catalyst. The generally accepted mechanism points out the hydride transfer step as the rate- and stereodetermining step, however computations based on these models do not totally fit with experimental observations. We hereby present a computational study that enlightens the stereochemical outcome and quantitatively reproduces the experimental enantiomeric excesses in a series of H-transfer hydrogenations. Our calculations suggest that the high stereocontrol usually attained with BINOL-derived phosphoric acids results mostly from the steric constraints generated by an aryl substituent of the catalyst, which hinders the access of the Hantzsch ester to the catalytic site and enforces approach through a specific way. It relies on a new model involving the preferential assembly of one of the stereomeric complexes formed by the chiral phosphoric acid and the two reaction partners. The stereodetermining step thus occurs prior to the H-transfer step.

  17. Investigation of the complex reaction coordinate of acid catalyzed amide hydrolysis from molecular dynamics simulations

    International Nuclear Information System (INIS)

    Zahn, Dirk

    2004-01-01

    The rate-determining step of acid catalyzed peptide hydrolysis is the nucleophilic attack of a water molecule to the carbon atom of the amide group. Therein the addition of the hydroxyl group to the amide carbon atom involves the association of a water molecule transferring one of its protons to an adjacent water molecule. The protonation of the amide nitrogen atom follows as a separate reaction step. Since the nucleophilic attack involves the breaking and formation of several bonds, the underlying reaction coordinate is rather complex. We investigate this reaction step from path sampling Car-Parrinello molecular dynamics simulations. This approach does not require the predefinition of reaction coordinates and is thus particularly suited for investigating reaction mechanisms. From our simulations the most relevant components of the reaction coordinate are elaborated. Though the C···O distance of the oxygen atom of the water molecule performing the nucleophilic attack and the corresponding amide carbon atom is a descriptor of the reaction progress, a complete picture of the reaction coordinate must include all three molecules taking part in the reaction. Moreover, the proton transfer is found to depend on favorable solvent configurations. Thus, also the arrangement of non-reacting, i.e. solvent water molecules needs to be considered in the reaction coordinate

  18. Application of acid-catalyzed hydrolysis of dispersed organic solvent in developing new microencapsulation process technology.

    Science.gov (United States)

    Lee, Honghwa; Lee, Sunhwa; Bhattacharjee, Himanshu; Sah, Hongkee

    2012-01-01

    The aim of this study was to evaluate a new microencapsulation technology employing an acid-catalyzed solvent extraction method in conjunction to an emulsion-based microencapsulation process. Its process consisted of emulsifying a dispersed phase of poly(D,L-lactide-co-glycolide) and isopropyl formate in an aqueous phase. This step was followed by adding hydrochloric acid to the resulting oil-in-water emulsion, in order to initiate the hydrolysis of isopropyl formate dissolved in the aqueous phase. Its hydrolysis caused the liberation of water-soluble species, that is, isopropanol and formic acid. This event triggered continual solvent leaching out of emulsion droplets, thereby initiating microsphere solidification. This new processing worked well for encapsulation of progesterone and ketoprofen that were chosen as a nonionizable model drug and a weakly acidic one, respectively. Furthermore, the structural integrity of poly(D,L-lactide-co-glycolide) was retained during microencapsulation. The new microencapsulation technology, being conceptually different from previous approaches, might be useful in preparing various polymeric particles.

  19. Acid-catalyzed disproportionation of oxoiron(IV) porphyrins to give oxoiron(IV) porphyrin radical cations.

    Science.gov (United States)

    Pan, Zhengzheng; Newcomb, Martin

    2011-06-01

    Disproportionation of oxoiron(IV) porphyrin (Compound II) to oxoiron(IV) porphyrin radical cation (Compound I) was studied in three P450 model systems with different electronic structures. Direct conversion of Compound II to Compound I has been observed for 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin (TDCPP) in acid-catalyzed reactions in a mixed solvent of acetonitrile and water (1:1, v/v) containing excess m-CPBA oxidant, with a second-order rate constant of (1.3 ± 0.2) × 10(2) M(-1) s(-1). The acid-catalyzed disproportionation heavily depends on the electron demand of the substituted aryl groups on the porphyrin macrocycle. The disproportionation equilibrium constants show drastic change for the three porphyrin systems.

  20. Levulinic acid production by two-step acid-catalyzed treatment of Quercus mongolica using dilute sulfuric acid.

    Science.gov (United States)

    Jeong, Hanseob; Jang, Soo-Kyeong; Hong, Chang-Young; Kim, Seon-Hong; Lee, Su-Yeon; Lee, Soo Min; Choi, Joon Weon; Choi, In-Gyu

    2017-02-01

    The objectives of this research were to produce a levulinic acid by two-step acid-catalyzed treatment of Quercus mongolica and to investigate the effect of treatment parameter (reaction temperature range: 100-230°C; sulfuric acid (SA) concentration range: 0-2%) on the levulinic acid yield. After 1 st step acid-catalyzed treatment, most of the hemicellulosic C5 sugars (15.6gg/100gbiomass) were released into the liquid hydrolysate at the reaction temperature of 150°C in 1% SA; the solid fraction, which contained 53.5% of the C6 sugars, was resistant to further loss of C6 sugars. Subsequently, 2 nd step acid-catalyzed treatment of the solid fractions was performed under more severe conditions. Finally, 16.5g/100g biomass of levulinic acid was produced at the reaction temperature of 200°C in 2% SA, corresponding to a higher conversion rate than during single-step treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Enhanced Hydrothermal Stability and Catalytic Activity of La x Zr y O z Mixed Oxides for the Ketonization of Acetic Acid in the Aqueous Condensed Phase

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Ruiz, Juan A. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Cooper, Alan R. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Li, Guosheng [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States; Albrecht, Karl O. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States

    2017-08-24

    Common ketonization catalysts such as ZrO2, CeO2, CexZryOz, and TiO2-based catalysts have been reported to lose surface area, undergo phase-transformation, and lose catalytic activity when utilized in the condensed aqueous phase. In this work, we synthesized and tested a series of LaxZryOz mixed metal oxides with different La:Zr atomic ratios with the goal of enhancing the catalytic activity and stability for the ketonization of acetic acid in condensed aqueous media at 568 K. We synthesized a hydrothermally stable LaxZryOz mixed-metal oxide catalyst with enhanced ketonization activities 360 and 40 times more active than La2O3 and ZrO2, respectively. Catalyst characterization techniques suggest that the formation of a hydrothermally stable catalyst which is isomorphic with tetragonal-ZrO2 under hydrothermal reaction conditions.

  2. Lewis-acid catalyzed depolymerization of Protobind lignin in supercritical water and ethanol

    NARCIS (Netherlands)

    Guvenatam, Burcu; Heeres, Erik H.J.; Pidko, Evgeny A.; Hensen, Ernie J. M.

    2016-01-01

    The use of metal acetates, metal chlorides and metal triflates as Lewis acid catalysts for the depolymerization of soda lignin under supercritical conditions was investigated. The reactions were carried out at 400 degrees C in water and ethanol. Lignin conversion in supercritical water led to

  3. Acid-catalyzed reductive amination of aldoses with 8-aminopyrene-1,3,6-trisulfonate.

    Science.gov (United States)

    Evangelista, R A; Guttman, A; Chen, F T

    1996-02-01

    The reductive amination of monosaccharides with 8-aminopyrene-1,3,6-trisulfonate (APTS) in seven different organic acids including the commonly used acetic acid was investigated by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. The correlation between the yields of the saccharide-APTS adducts and pKa of the organic acid catalyst is consistent with general acid catalysis of the rate-determining step of the reductive amination reaction. Derivatization in the presence of organic acids of higher strength than acetic acid produced substantially higher yields of APTS-sugar adducts, an effect which is more pronounced for N-acetylamino sugars. Optimum yields were obtained using citric acid as a catalyst. Conversion of a few nanomoles of neutral saccharides to the APTS derivatives is achieved at 75 degrees C in less than 60 min.

  4. A two-step acid-catalyzed process for the production of biodiesel from rice bran oil

    Energy Technology Data Exchange (ETDEWEB)

    Zullaikah, S.; Lai, Chao Chin; Vali, S.R.; Ju, Yi Hsu [National Taiwan Univ. of Science and Technology, Taipei (China). Dept. of Chemical Engineering

    2005-11-15

    A study was undertaken to examine the effect of temperature, moisture and storage time on the accumulation of free fatty acid in the rice bran. Rice bran stored at room temperature showed that most triacylglyceride was hydrolyzed and free fatty acid (FFA) content was raised up to 76% in six months. A two-step acid-catalyzed methanolysis process was employed for the efficient conversion of rice bran oil into fatty acid methyl ester (FAME). The first step was carried out at 60 {sup o}C. Depending on the initial FFA content of oil, 55-90% FAME content in the reaction product was obtained. More than 98% FFA and less than 35% of TG were reacted in 2 h. The organic phase of the first step reaction product was used as the substrate for a second acid-catalyzed methanolysis at 100 {sup o}C. By this two-step methanolysis reaction, more than 98% FAME in the product can be obtained in less than 8 h. Distillation of reaction product gave 99.8% FAME (biodiesel) with recovery of more than 96%. The residue contains enriched nutraceuticals such as {gamma}-oryzanol (16-18%), mixture of phytosterol, tocol and steryl ester (19-21%). (author)

  5. Production of Biodiesel from High Acid Value Waste Cooking Oil Using an Optimized Lipase Enzyme/Acid-Catalyzed Hybrid Process

    Directory of Open Access Journals (Sweden)

    N. Saifuddin

    2009-01-01

    Full Text Available The present study is aimed at developing an enzymatic/acid-catalyzed hybrid process for biodiesel production using waste cooking oil with high acid value (poor quality as feedstock. Tuned enzyme was prepared using a rapid drying technique of microwave dehydration (time required around 15 minutes. Further enhancement was achieved by three phase partitioning (TPP method. The results on the lipase enzyme which was subjected to pH tuning and TPP, indicated remarkable increase in the initial rate of transesterification by 3.8 times. Microwave irradiation was found to increase the initial reaction rates by further 1.6 times, hence giving a combined increase in activity of about 5.4 times. The optimized enzyme was used for hydrolysis and 88% of the oil taken initially was hydrolyzed by the lipase. The hydrolysate was further used in acid-catalyzed esterification for biodiesel production. By using a feedstock to methanol molar ratio of 1:15 and a sulphuric acid concentration of 2.5%, a biodiesel conversion of 88% was obtained at 50 °C for an hour reaction time. This hybrid process may open a way for biodiesel production using unrefined and used oil with high acid value as feedstock.

  6. Studies of Grafted and Sulfonated Spiro Poly(isatin-ethersulfone Membranes by Super Acid-Catalyzed Reaction

    Directory of Open Access Journals (Sweden)

    Lei Jin

    2016-03-01

    Full Text Available Spiro poly(isatin-ethersulfone polymers were prepared from isatin and bis-2,6-dimethylphenoxyphenylsulfone by super acid catalyzed polyhydroxyalkylation reactions. We designed and synthesized bis-2,6-dimethylphenoxyphenylsulfone, which is structured at the meta position steric hindrance by two methyl groups, because this structure minimized crosslinking reaction during super acid catalyzed polymerization. In addition, sulfonic acid groups were structured in both side chains and main chains to form better polymer chain morphology and improve proton conductivity. The sulfonation reactions were performed in two steps which are: in 3-bromo-1-propanesulfonic acid potassium salt and in con. sulfuric acid. The membrane morphology was studied by tapping mode atomic force microscope (AFM. The phase difference between the hydrophobic polymer main chain and hydrophilic sulfonated units of the polymer was shown to be the reasonable result of the well phase separated structure. The correlations of proton conductivity, ion exchange capacity (IEC and single cell performance were clearly described with the membrane morphology.

  7. Selective and recyclable depolymerization of cellulose to levulinic acid catalyzed by acidic ionic liquid.

    Science.gov (United States)

    Ren, Huifang; Girisuta, Buana; Zhou, Yonggui; Liu, Li

    2015-03-06

    Cellulose depolymerization to levulinic acid (LA) was catalyzed by acidic ionic liquids (ILs) selectively and recyclably under hydrothermal conditions. The effects of reaction temperature, time, water amount and cellulose intake were investigated. Dilution effect becomes more pronounced at lower cellulose intake, dramatically improving the yield of LA to 86.1%. A kinetic model has been developed based on experimental data, whereby a good fit was obtained and kinetic parameters were derived. The relationships between IL structure, polymeric structure and depolymerization efficiency were established, shedding light on the in-depth catalytic mechanism of IL, inclusive of acidity and hydrogen bonding ability. The LA product can be readily separated through extraction by methyl isobutyl ketone (MIBK) and IL can be reused over five cycles without loss of activity. This environmentally friendly methodology can be applied to selective production of LA from versatile biomass feedstocks, including cellulose and derivatives, glucose, fructose and HMF. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. The role of germacrene D as a precursor in sesquiterpene biosynthesis: investigations of acid catalyzed, photochemically and thermally induced rearrangements.

    Science.gov (United States)

    Bülow, N; Konig, W A

    2000-09-01

    Germacrene D is considered as a precursor of many sesquiterpene hydrocarbons. We have investigated the acid catalyzed as well as the photochemically and thermally induced rearrangement processes of germacrene D isolated from several Solidago species, which contain both enantiomers of germacrene D. Enantiomeric mixtures of sesquiterpenes of the cadinane, eudesmane (selinane), oppositane, axane, isodaucane, and bourbonane group as well as isogermacrene D were identified as main products and made available as reference compounds for structure investigations and stereochemical assignments of plant constituents. Delta-amorphene, one of the rearrangement products, was identified as a natural product for the first time. The absolute configuration of gamma-amorphene was revised by correlation with the absolute configuration of germacrene D. The mechanisms of the rearrangement reactions are discussed.

  9. Qualitative analysis of products formed during the acid catalyzed liquefaction of bagasse in ethylene glycol.

    Science.gov (United States)

    Zhang, Ting; Zhou, Yujie; Liu, Dehua; Petrus, Leo

    2007-05-01

    Bagasse was liquefied in ethylene glycol (EG) catalyzed by sulfuric acid at 190 degrees C under atmospheric pressure. The compositions of the crude products obtained were analyzed after separating them into three fractions: a water-soluble fraction, an acetone-soluble fraction and a residue. With infrared, gel permeation chromatography and elemental analyses, the residue mainly included undissolved cellulose and lignin derivatives and the acetone-soluble fraction mainly contained lignin degradation products with high molecular weights. The water-soluble fraction, after further analyzed by GC-MS and HPLC, showed EG, diethylene glycol, EG derivatives, saccharides, alcohols, aldehydes, ketones, phenols, especially some acids such as formic acid, levulinic acid, acetic acid, oxalic acid and 2-hydroxy-butyric acid and their esters. The Higher Heating Value (HHV) of the residue and the acetone-soluble fractions were higher than that of bagasse. The results showed that some useful chemicals and biofuels could be obtained by this process.

  10. Direct conversion of lignocellulose to levulinic acid catalyzed by ionic liquid.

    Science.gov (United States)

    Liu, Li; Li, Zhenrui; Hou, Wuxin; Shen, Haiyan

    2018-02-01

    Acidic ionic liquid (IL) [C 3 SO 3 Hmim]HSO 4 was applied to catalyze lignocellulose conversion to levulinic acid (LA) in one pot with high selectivity under hydrothermal conditions. Through the optimization of reaction conditions, the highest yield of LA is 96.6mol% (21.6wt%) based on the amount of C6-sugars in the straw. The relationship between IL structure and LA yield was established, disclosing that acidity and hydrogen bonding ability of anions are crucial to the yield of LA. Moreover, the LA product can be readily separated through extraction by methyl isobutyl ketone (MIBK) and IL can be reused over 5 cycles without loss of activity. In addition, the chemical structures and morphologies of the solid residues were investigated by DTG, SEM and IR, demonstrating the gradual conversion process of cellulose and hemicellulose accompanied by the formation of humin byproducts, whereas the lignin fraction of the straw sustains the scaffold structure without modifications during the reaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Synthesis of Tetrahydropyridazines by a Metal-carbene Directed Highly Enantioselective Vinylogous N-H Insertion/Lewis Acid Catalyzed Diastereoselective Mannich Addition

    Science.gov (United States)

    Xu, Xinfang; Zavalij, Peter Y.

    2012-01-01

    A versatile reaction cascade triggered by Rh(II)-catalyzed diazo decomposition followed by a vinylogous N-H insertion/Lewis acid catalyzed Mannich addition that produces highly substituted 1,2,3,6-tetrahydropyridazines in up to 97% ee with high yield and diastereocontrol has been developed. PMID:22945294

  12. Synthesis of Tetrahydropyridazines by a Metal-carbene Directed Highly Enantioselective Vinylogous N-H Insertion/Lewis Acid Catalyzed Diastereoselective Mannich Addition

    OpenAIRE

    Xu, Xinfang; Zavalij, Peter Y.; Doyle, Michael P.

    2012-01-01

    A versatile reaction cascade triggered by Rh(II)-catalyzed diazo decomposition followed by a vinylogous N-H insertion/Lewis acid catalyzed Mannich addition that produces highly substituted 1,2,3,6-tetrahydropyridazines in up to 97% ee with high yield and diastereocontrol has been developed.

  13. Optimization and kinetic analysis on the sulfuric acid - Catalyzed depolymerization of wheat straw.

    Science.gov (United States)

    Wu, Qian-Qian; Ma, Yu-Long; Chang, Xuan; Sun, Yong-Gang

    2015-09-20

    The objectives of this work were to optimize the experimental condition and to study the kinetic behavior of wheat straw depolymerization with sulfuric acid (2 wt%, 3 wt%, and 4 wt%) at different temperatures (120°C, 130°C, and 140°C). The two-fraction kinetic model was obtained for the prediction of the generations of product and by-product during depolymerization. The kinetic parameters of the two-fraction model were analyzed using an Arrhenius-type equation. Applying the kinetic two-fraction model, the optimum condition for wheat straw depolymerization was 3 wt% H2SO4 at 130°C for 75 min, which yielded a high concentration of fermentable sugars (xylose 8.934 g/L, glucose 1.363 g/L, and arabinose 1.203 g/L) and low concentrations of microbial inhibitors (furfural 0.526 g/L and acetic acid 1.192 g/L). These results suggest that the model obtained in this study can satisfactorily describe the formation of degradation products and the depolymerization mechanism of wheat straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    and in sedimented rifts adjacent to continental margins. The hydrothermal deposits mainly occur in the tectonically active regions, where plates shift and spread creating fissures in the seafloor. Mineralization at the spreading ridges is the result of sea-floor... processes. Submarine hydrothermal circulation in the oceanic crust and its activity on the ocean floor are fundamental processes controlling the transfer of energy and material from the lithosphere to the hydrosphere. Thermally induced circulation...

  15. Synthesis of deuterium-labeled desipramine through acid-catalyzed exchange reactions and the stability of deuterium labeling

    International Nuclear Information System (INIS)

    Baba, Shigeo; Sasaki, Yukihito

    1987-01-01

    Synthesis of three forms of selectively deuterated desipramine with high isotopic purity through acid-catalyzed hydrogen-deuterium exchange reactions and the stability of deuterium labeling are described. Deuterated desipramine labeled at positions 2,4,6 and 8 [DMI-d 4 (I)] was prepared directly by heating desipramine in 10% DCI-D 2 O at 80deg C for 8 hours. Desipramine labeled at all eight aromatic positions (DMI-d 8 ) was synthesized from iminodibenzyl-1,2,3,4,6,7,8,9-d 8 . Desipramine labeled at positions 1,3,7 and 9 [DMI-d 4 (II)] was obtained by the ''back-exchange'' of DMI-d 8 under the protio condition according to the exchange procedure of DMI-d 4 (I). Deuterium atoms labeled at positions 2,4,6 and 8 of desipramine were eliminated rapidly in 1N HCl at 80deg C, but those labeled at positions 1,3,7 and 9 of desipramine were quite chemically stable. (author)

  16. A kinetic mechanistic study of acid-catalyzed alkylation of isobutane with C4-olefins at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, B.M.

    1978-01-01

    A kinetic and mechanistic study of sulfuric acid-catalyzed alkylation of isobutane with C/sub 4/-Olefins at Low Temperatures(-20/sup 0/ to 0/sup 0/C) was based on a new two-step reaction sequence in which the desired first-step reactions are between acid and olefin to form sulfates and the desired second-step reactions are between sulfates and isobutane to form mostly trimethylpentanes. Linear butenes formed stable sulfates that formed alkylates of exceptionally high quality, up to 100 Research octane, whereas isobutylene and trimethylpentene mainly polymerized during the first step, and the alkylate produced had only 90 Research octane. Trimethylpentanes and dimethylhexanes, when contacted with concentrated sulfuric acid at -10/sup 0/ to +25/sup 0/C, degraded and isomerized to form C/sub 4/-C/sub 9/ and higher isoparaffins and acid-soluble hydrocarbons (conjunct polymers). For the two-step process and the degradation and isomerization reactions, kinetic models based on reaction at the interface were developed; but for isoolefins, a polymerization-cracking sequence (via C/sub 12/- and even C/sub 16/-olefins) is the preferred route. Commercial applications of the results are proposed.

  17. Ruthenium Hydride/Brønsted Acid-Catalyzed Tandem Isomerization/N-Acyliminium Cyclization Sequence for the Synthesis of Tetrahydro-β-carbolines

    DEFF Research Database (Denmark)

    Hansen, Casper Lykke; Clausen, Janie Regitse Waël; Ohm, Ragnhild Gaard

    2013-01-01

    This paper describes an efficient tandem sequence for the synthesis of 1,2,3,4-tetrahydro-β-carbolines (THBCs) relying on a ruthenium hydride/Brønsted acid- catalyzed isomerization of allylic amides to N-acyliminium ion intermediates which are trapped by a tethered indolenucleophile. The methodol......This paper describes an efficient tandem sequence for the synthesis of 1,2,3,4-tetrahydro-β-carbolines (THBCs) relying on a ruthenium hydride/Brønsted acid- catalyzed isomerization of allylic amides to N-acyliminium ion intermediates which are trapped by a tethered indolenucleophile...... the Suzuki cross-coupling reaction to the isomerization/N-acyliminium cyclization sequence. Finally, diastereo- and enantioselective versions of the title reaction have been examined using substrate control (with dr >15: 1) and asymmetric catalysis (ee up to 57%), respectively...

  18. Hydrothermal Processes

    Science.gov (United States)

    German, C. R.; von Damm, K. L.

    2003-12-01

    What is Hydrothermal Circulation?Hydrothermal circulation occurs when seawater percolates downward through fractured ocean crust along the volcanic mid-ocean ridge (MOR) system. The seawater is first heated and then undergoes chemical modification through reaction with the host rock as it continues downward, reaching maximum temperatures that can exceed 400 °C. At these temperatures the fluids become extremely buoyant and rise rapidly back to the seafloor where they are expelled into the overlying water column. Seafloor hydrothermal circulation plays a significant role in the cycling of energy and mass between the solid earth and the oceans; the first identification of submarine hydrothermal venting and their accompanying chemosynthetically based communities in the late 1970s remains one of the most exciting discoveries in modern science. The existence of some form of hydrothermal circulation had been predicted almost as soon as the significance of ridges themselves was first recognized, with the emergence of plate tectonic theory. Magma wells up from the Earth's interior along "spreading centers" or "MORs" to produce fresh ocean crust at a rate of ˜20 km3 yr-1, forming new seafloor at a rate of ˜3.3 km2 yr-1 (Parsons, 1981; White et al., 1992). The young oceanic lithosphere formed in this way cools as it moves away from the ridge crest. Although much of this cooling occurs by upward conduction of heat through the lithosphere, early heat-flow studies quickly established that a significant proportion of the total heat flux must also occur via some additional convective process (Figure 1), i.e., through circulation of cold seawater within the upper ocean crust (Anderson and Silbeck, 1981). (2K)Figure 1. Oceanic heat flow versus age of ocean crust. Data from the Pacific, Atlantic, and Indian oceans, averaged over 2 Ma intervals (circles) depart from the theoretical cooling curve (solid line) indicating convective cooling of young ocean crust by circulating seawater

  19. Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

    KAUST Repository

    Ajitha, Manjaly John

    2015-09-15

    The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X). The nucleophilic ring opening of epoxide by thiobenzoic acid was found to proceed via a concerted termolecular transition state with a simultaneous dual proton transfer to yield the β-hydroxy thioester product. Electrostatic interactions together with the steric environment inside the chiral catalyst play an important role in determining the enantioselectivity of the reaction.

  20. Synthesis of tetrahydropyridazines by a metal-carbene-directed enantioselective vinylogous N-H insertion/Lewis acid-catalyzed diastereoselective Mannich addition.

    Science.gov (United States)

    Xu, Xinfang; Zavalij, Peter Y; Doyle, Michael P

    2012-09-24

    A versatile cascade of reactions, triggered by Rh(II)-catalyzed diazo decomposition followed by a vinylogous N-H insertion/Lewis acid catalyzed Mannich addition, that produces highly substituted 1,2,3,6-tetrahydropyridazines in up to 97 % ee with high yield and diastereocontrol has been developed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Brønsted acid catalyzed regioselective aza-Ferrier reaction : A novel synthetic method of α-(N-Boc-2-pyrrolidinyl)aldehydes

    OpenAIRE

    Tayama, Eiji; Otoyama, Seijun; Isaka, Wataru

    2008-01-01

    The 1,4-elimination reaction of (Z)-N-Boc-2-(4-methoxy-2-alkenyloxy)pyrrolidines (1) is shown to proceed with high (1E,3E)-stereoselectivity to afford N-Boc-2-(1,3-dienyloxy)pyrrolidines (2); the Bronsted acid catalyzed aza-Ferrier reaction of the N-Boc-2-(1,3-dienyloxy)pyrrolidines (2) provides a-(N-Boc-2-pyrrolidinyl) aldehydes (3) in excellent yields with high a-regioselectivities.

  2. Phase Transformation of Hydrothermally Synthesized Nanoparticle ...

    African Journals Online (AJOL)

    Mild hydrothermal hydrolysis of TiCl4 produces nanorods of the rutile phase of titanium dioxide in high yield, while in the presence of organic acids (citric, acetic, D-tartaric and benzoic acids) anatase is the only product. The effect of these organic acids on the products of the hydrolysis reaction as well as the reaction kinetics ...

  3. The acid-catalyzed hydrolysis of an α-pinene-derived organic nitrate: kinetics, products, reaction mechanisms, and atmospheric impact

    Science.gov (United States)

    Rindelaub, Joel D.; Borca, Carlos H.; Hostetler, Matthew A.; Slade, Jonathan H.; Lipton, Mark A.; Slipchenko, Lyudmila V.; Shepson, Paul B.

    2016-12-01

    data, product identification confirms that a unimolecular specific acid-catalyzed mechanism is responsible for organic nitrate hydrolysis under acidic conditions. The free energies and enthalpies of the isobutyl nitrate hydrolysis intermediates and products were calculated using a hybrid density functional (ωB97X-V) to support the proposed mechanisms. These findings provide valuable information regarding the organic nitrate hydrolysis mechanism and its contribution to the fate of atmospheric NOx, aerosol phase processing, and BSOA composition.

  4. A chiral Brønsted acid-catalyzed highly enantioselective Mannich-type reaction of α-diazo esters with in situ generated N-acyl ketimines.

    Science.gov (United States)

    Unhale, Rajshekhar A; Sadhu, Milon M; Ray, Sumit K; Biswas, Rayhan G; Singh, Vinod K

    2018-04-03

    A chiral phosphoric acid-catalyzed asymmetric Mannich-type reaction of α-diazo esters with in situ generated N-acyl ketimines, derived from 3-hydroxyisoindolinones has been demonstrated in this communication. A variety of isoindolinone-based α-amino diazo esters bearing a quaternary stereogenic center were afforded in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the products has been depicted by the hydrogenation of the diazo moiety of adducts.

  5. Clostebol acetate

    Directory of Open Access Journals (Sweden)

    Elisabetta Maccaroni

    2011-08-01

    Full Text Available The title compound, C21H29ClO3 [systematic name (8R,9S,10R,13S,14S,17S-4-chloro-3-oxoandrost-4-en-17β-yl acetate], is a 4-chloro derivative of testosterone, used as an anabolic androgenic agent or applied topically in ophthalmological and dermatological treatments. The absolute configurations at positions 8, 9, 10, 13, 14 and 17 were established by refinement of the Flack parameter as R, S, R, S, S, and S, respectively. Rings B and C of the steroid ring system adopt chair conformations, ring A has a half-chair conformation, while ring D is in a C13 envelope conformation. Ring B and C, and C and D are trans fused. In the crystal, molecules are linked by a weak C—H...O interaction.

  6. Acid-catalyzed hydrogenation of olefins. A theoretical study of the HF- and H/sub 3/O/sup +/-catalyzed hydrogenation of ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Siria, J.C.; Duran, M.; Lledos, A.; Bertran, J.

    1987-12-09

    The HF- and H/sub 3/O/sup +/-catalyzed hydrogenation of ethylene and the direct addition of molecular hydrogen to ethylene have been studied theoretically by means of ab initio MO calculations using different levels of theory. The main results are that catalysis by HF lowers the potential energy barrier to a large extent, while catalysis by H/sub 3/O/sup +/ diminishes dramatically the barrier for the reaction. Entropic contributions leave these results unchanged. The mechanisms of the two acid-catalyzed hydrogenations are somewhat different. While catalysis by HF exhibits bifunctional characteristics, catalysis by H/sub 3/O/sup +/ proceeds via an initial formation of a carbocation. It is shown that catalysis by strong acids may be an alternate way for olefin hydrogenation.

  7. Quantitative analysis of acid-catalyzed levulinic acid product mixture from cellulose by mixed-mode liquid chromatography.

    Science.gov (United States)

    Liu, Junyan; Li, Jiwen; Zheng, Junlin; Wang, Chuan

    2017-10-01

    A mixed-mode weak anion-exchange/reversed-phase liquid chromatography (LC) column was successfully applied for the analysis of levulinic acid (4-oxopentanoic acid, LA) product mixture derived from cellulose. Due to the existence of ionic and neutral byproducts, the analysis of the product mixture usually requires ion chromatography, LC and gas chromatography simultaneously. The new method enables accomplishment of the analysis in one LC run within 6min. LC mobile phase of 10mM phosphate buffer containing 5% acetonitrile with pH=5.5 was used. The linear regression coefficients for the UV signal of standard compounds with the corresponding mass concentrations were greater than 0.999. The method recoveries were between 98.57-103.48%. The limits of quantification were 5, 10,1000, 1500 and 3000ng/mL for 5-hydroxymethylfurfural, furfural, acetic acid, formic acid and LA respectively. The mixed-mode column exhibits comprehensive separation mechanism of both reversed-phase and ion-exchange interactions. The mobile phase with different pH, organic modifier solvent and buffer concentration provided flexible LC method for the sample with different complexity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Steam reforming of acetic acid - A major component in the volatiles formed during gasification of humin

    NARCIS (Netherlands)

    Hoang, Thi Minh Chau; Geerdink, Bert; Sturm, Jacobus Marinus; Lefferts, Leonardus; Seshan, Kulathuiyer

    2015-01-01

    Acetic acid and phenols are the major components of the condensable by-products in the low temperature de-volatilisation stage of humin during gasification. Catalytic steam reforming of acetic acid using supported Ni on ceria-zirconia mixed oxide prepared via the hydrothermal route is discussed. The

  9. Obtaining of inulin acetate

    OpenAIRE

    Khusenov, Arslonnazar; Rakhmanberdiev, Gappar; Rakhimov, Dilshod; Khalikov, Muzaffar

    2014-01-01

    In the article first obtained inulin ester inulin acetate, by etherification of inulin with acetic anhydride has been exposed. Obtained product has been studied using elementary analysis and IR spectroscopy.

  10. Acid-, base-, and lewis-acid-catalyzed heterolysis of methoxide from an alpha-hydroxy-beta-methoxy radical: models for reactions catalyzed by coenzyme B12-dependent diol dehydratase.

    Science.gov (United States)

    Xu, Libin; Newcomb, Martin

    2005-11-11

    [Reaction: see text].A model for glycol radicals was employed in laser flash photolysis kinetic studies of catalysis of the fragmentation of a methoxy group adjacent to an alpha-hydroxy radical center. Photolysis of a phenylselenylmethylcyclopropane precursor gave a cyclopropylcarbinyl radical that rapidly ring opened to the target alpha-hydroxy-beta-methoxy radical (3). Heterolysis of the methoxy group in 3 gave an enolyl radical (4a) or an enol ether radical cation (4b), depending upon pH. Radicals 4 contain a 2,2-diphenylcyclopropane reporter group, and they rapidly opened to give UV-observable diphenylalkyl radicals as the final products. No heterolysis was observed for radical 3 under neutral conditions. In basic aqueous acetonitrile solutions, specific base catalysis of the heterolysis was observed; the pK(a) of radical 3 was determined to be 12.5 from kinetic titration plots, and the ketyl radical formed by deprotonation of 3 eliminated methoxide with a rate constant of 5 x 10(7) s(-1). In the presence of carboxylic acids in acetonitrile solutions, radical 3 eliminated methanol in a general acid-catalyzed reaction, and rate constants for protonation of the methoxy group in 3 by several acids were measured. Radical 3 also reacted by fragmentation of methoxide in Lewis-acid-catalyzed heterolysis reactions; ZnBr2, Sc(OTf)3, and BF3 were found to be efficient catalysts. Catalytic rate constants for the heterolysis reactions were in the range of 3 x 10(4) to 2 x 10(6) s(-1). The Lewis-acid-catalyzed heterolysis reactions are fast enough for kinetic competence in coenzyme B12 dependent enzyme-catalyzed reactions of glycols, and Lewis-acid-catalyzed cleavages of beta-ethers in radicals might be applied in synthetic reactions.

  11. Hydrolyses of 2- and 4-fluoro N-heterocycles. 3. Nucleophilic catalysis by buffer bases in the general acid catalyzed hydrolysis of 4-fluoroquinaldine

    International Nuclear Information System (INIS)

    Muscio, O.J. Jr.; Theobald, P.G.; Rutherford, D.R.

    1989-01-01

    Pseudo-first-order rate constants and catalytic rate constants are reported for the buffer-catalyzed hydrolysis of 4-fluoroquinaldine (1) in carboxylic acid and phosphoric acid buffers. The buffer catalysis is consistent with specific acid, general base catalysis. Hydrolyses in 99% 18 O-labeled acetate, indicate that the predominant catalytic mode for the acetic acid/acetate buffer system is nucleophilic catalysis by the acetate anion coupled with specific acid catalysis. The other buffers presumably react in a similar manner. A Broensted-type plot of the catalytic rate constants for hydrolysis of protonated 1 has a slope of 0.57, with formate deviating positively from the line determined by acetate, chloroacetate, monohydrogen phosphate, and water. This Broensted slope is less than that found for hydrolysis of the 2-fluoro-1-methylpyridinium ion, 2, but is still within the range expected for aromatic nucleophilic substitution. Rate constants and 18 O-labeling results for hydrolysis in acetate buffer are also reported for 4-acetoxyquinaldine (3), the proposed intermediate in the acetate-catalyzed hydrolysis of 1. 15 references, 5 figures, 3 tables

  12. Sequential one-pot synthesis of imidazoles and 2H-imidazolones from β-ketoamines, acylating agents and ammonium acetate

    Energy Technology Data Exchange (ETDEWEB)

    Jalani, Hitesh B.; Venkateswararao, Edda; Manickam, Manoj; Jung, Sang Hun [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon (Korea, Republic of)

    2016-12-15

    An efficient, practical, straight forward, and transition metal-free three-component synthesis of diversely substituted imidazoles and 2H-imidazolones from β-ketoamines, acylating agents, and ammonium acetate has been described herein. This approach involves [3+1+1] cyclization through consecutive formation of three C–N bonds as a sequence of initial amidation of β-ketoamines with acylating agent, β-iminoketoamide formation with ammonia, and acid catalyzed concomitant cyclodehydration to afford the imidazoles and 2H-imidazolones. This methodology has advantages such as single flask operation, readily available starting materials, mild conditions, broad functional groups tolerance, and simple work-up procedure.

  13. Pallidol hexa-acetate ethyl acetate monosolvate.

    Science.gov (United States)

    Mao, Qinyong; Taylor, Dennis K; Ng, Seik Weng; Tiekink, Edward R T

    2013-01-01

    The entire mol-ecule of pallidol hexa-acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis-[4-(acet-yloxy)phen-yl]-4b,5,9b,10-tetra-hydro-indeno-[2,1-a]indene-1,3,6,8-tetrayl tetra-acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol-ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ▶). Acta Cryst. D65, 148-155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa-acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å) is 54.73 (6)°, indicating a significant fold in the mol-ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C-O(carb-oxy)-C-C torsion angles = -70.24 (14), -114.43 (10) and -72.54 (13)°]. In the crystal, a three-dimensional architecture is sustained by C-H⋯O inter-actions which encompass channels in which the disordered ethyl acetate mol-ecules reside.

  14. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

    2011-01-01

    This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During...... the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed...... by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction...

  15. Acetic acid, a relatively green single-use catalyst for hydrogen generation from sodium borohydride

    Energy Technology Data Exchange (ETDEWEB)

    Akdim, O.; Demirci, U.B.; Miele, P. [Universite Lyon 1, CNRS, UMR 5615, Laboratoire des Multimateriaux et Interfaces, 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France)

    2009-09-15

    Acid-catalyzed hydrolysis of sodium borohydride (NaBH{sub 4}) has been studied (reactivity and kinetics) at high acid concentration (0.32 M). A mineral (hydrochloric acid, HCl) and an organic benign (acetic acid, CH{sub 3}COOH) acid have been chosen. Our study has three distinct objectives, namely: (i) combining the simplicity of the storage of solid NaBH{sub 4} with the simplicity of the aqueous solution of acid; (ii) showing CH{sub 3}COOH can be as reactive as HCl in specific well-chosen operating conditions; and (iii) emphasizing the relative greenness of the CH{sub 3}COOH-based process. All of these objectives have been fulfilled and show that CH{sub 3}COOH is a benign relatively green acid catalyst of choice for catalyzing hydrogen generation from NaBH{sub 4}, the acid-water-NaBH{sub 4} system being quite simple. (author)

  16. Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments

    Science.gov (United States)

    Bell, James B.; Reid, William D. K.; Pearce, David A.; Glover, Adrian G.; Sweeting, Christopher J.; Newton, Jason; Woulds, Clare

    2017-12-01

    Hydrothermal sediments are those in which hydrothermal fluid is discharged through sediments and are one of the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermal and background areas of the Bransfield Strait (1050-1647 m of depth). Microbial composition, biomass, and fatty acid signatures varied widely between and within hydrothermally active and background sites, providing evidence of diverse metabolic activity. Several species had different feeding strategies and trophic positions between hydrothermally active and inactive areas, and the stable isotope values of consumers were not consistent with feeding morphology. Niche area and the diversity of microbial fatty acids was lowest at the most hydrothermally active site, reflecting trends in species diversity. Faunal uptake of chemosynthetically produced organics was relatively limited but was detected at both hydrothermal and non-hydrothermal sites, potentially suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.

  17. Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

    Directory of Open Access Journals (Sweden)

    K. Yamamura

    2016-09-01

    Full Text Available This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

  18. Production of Valuables Organic Acids from Organic Wastes with Hydrothermal Treatment Process

    Directory of Open Access Journals (Sweden)

    Muhammad Faisal

    2009-06-01

    Full Text Available This article reports production of valuables organic acids from the hydrothermal treatment of representative organic wastes and compounds (i. e. domestic sludge, proteinaceous, cellulosic and plastic wastes with or without oxidant (H2O2. Organic acids such as acetic, formic, propionic, succinic and lactic acids were obtained in significant amounts. At 623 K (16.5 MPa, acetic acid of about 26 mg/g-dry waste fish entrails was obtained. This increased to 42 mg/g dry waste fish entrails in the presence of H2O2. Experiments on glucose to represent cellulosic wastes were also carried out, getting acetic acid of about 29 mg/g-glucose. The study was extended to terephthalic acid and glyceraldehyde, reaction intermediates of hydrothermal treatment of PET plastic wastes and glucose, respectively. Studies on temperature dependence of formation of organic acids showed thermal stability of acetic acid, whereas, formic acid decomposed readily under hydrothermal conditions. In general, results demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product. Keywords: hydrothermal treatment, organic acids, organic wastes, oxidant, supercritical water oxidation

  19. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  20. Four mechanisms in the reactions of 3-aminopyrrole with 1,3,5-triazines: inverse electron demand Diels-Alder cycloadditions vs S(N)Ar reactions via uncatalyzed and acid-catalyzed pathways.

    Science.gov (United States)

    De Rosa, Michael; Arnold, David; Hartline, Douglas

    2013-09-06

    Reaction of 3-aminopyrrole with seven 1,3,5-triazines was studied in a one-step reaction (in situ formation of 3-aminopyrrole) and a two-step reaction (using the tetraphenylborate salt and an amine base). An inverse-electron demand Diels-Alder reaction (IEDDA) was observed with R1 = CF3, CO2Et, and H with the formation of 5H-pyrrolo[3,2-d]pyrimidine derivatives. S(N)Ar was observed when 2,4,6-trifluoro- or 2,4,6-trichloro-1,3,5-triazine were used--1,3,5-triazines that had leaving groups. If excess 1,3,5-triazine was present the initial S(N)Ar product reacted further, in the presence of acid and water, with another equivalent of 1,3,5-triazine to give compounds containing three linked heterocyclic rings. No reaction was observed with R1 = C6H5 and OCH3. Four mechanisms are proposed to explain the experimental results: uncatalyzed and acid catalyzed inverse electron demand Diels-Alder cascades leading to cycloaddition, and uncatalyzed and acid-catalyzed S(N)Ar reactions leading, respectively, to single and double substitution products. Acid catalysis was a factor when there was reduced reactivity in either reactant.

  1. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, D.

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of

  2. The Lassen hydrothermal system

    Science.gov (United States)

    Ingebritsen, Steven E.; Bergfeld, Deborah; Clor, Laura; Evans, William C.

    2016-01-01

    The active Lassen hydrothermal system includes a central vapor-dominated zone or zones beneath the Lassen highlands underlain by ~240 °C high-chloride waters that discharge at lower elevations. It is the best-exposed and largest hydrothermal system in the Cascade Range, discharging 41 ± 10 kg/s of steam (~115 MW) and 23 ± 2 kg/s of high-chloride waters (~27 MW). The Lassen system accounts for a full 1/3 of the total high-temperature hydrothermal heat discharge in the U.S. Cascades (140/400 MW). Hydrothermal heat discharge of ~140 MW can be supported by crystallization and cooling of silicic magma at a rate of ~2400 km3/Ma, and the ongoing rates of heat and magmatic CO2 discharge are broadly consistent with a petrologic model for basalt-driven magmatic evolution. The clustering of observed seismicity at ~4–5 km depth may define zones of thermal cracking where the hydrothermal system mines heat from near-plastic rock. If so, the combined areal extent of the primary heat-transfer zones is ~5 km2, the average conductive heat flux over that area is >25 W/m2, and the conductive-boundary length <50 m. Observational records of hydrothermal discharge are likely too short to document long-term transients, whether they are intrinsic to the system or owe to various geologic events such as the eruption of Lassen Peak at 27 ka, deglaciation beginning ~18 ka, the eruptions of Chaos Crags at 1.1 ka, or the minor 1914–1917 eruption at the summit of Lassen Peak. However, there is a rich record of intermittent hydrothermal measurement over the past several decades and more-frequent measurement 2009–present. These data reveal sensitivity to climate and weather conditions, seasonal variability that owes to interaction with the shallow hydrologic system, and a transient 1.5- to twofold increase in high-chloride discharge in response to an earthquake swarm in mid-November 2014.

  3. Efficient synthesis of zinc-containing mesoporous silicas by microwave irradiation method and their high activities in acetylation of 1,2-dimethoxybenzene with acetic anhydride

    Directory of Open Access Journals (Sweden)

    K. Bachari

    2016-09-01

    Full Text Available A series of acid zinc-containing mesoporous materials have been synthesized by microwave irradiation method with different Si/Zn ratios (Si/Zn = 100, 65, 15 and characterized by several spectroscopic techniques such as: N2 physical adsorption, ICP, XRD, TEM, FT-IR and a temperature-programmed-desorption (TPD of pyridine. The liquid phase of acetylation of 1,2-dimethoxybenzene with acetic anhydride has been investigated over this series of catalysts. In fact, the catalyst Zn-JLU-15 (15 showed bigger performance in the acid-catalyzed acetylation of 1,2-dimethoxybenzene employing acetic anhydride as an acylating agent. Furthermore, the kinetics of the acetylation of 1,2-dimethoxybenzene over these catalysts have also been investigated.

  4. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica

    2014-01-01

    Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided...... into biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass...... into liquid biofuels, with the aim of describing the current status and development challenges of the technology. During the hydrothermal liquefaction process, the biomass macromolecules are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive...

  5. Sol-gel/hydrothermal synthesis of mixed metal oxide of Titanium and ...

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal condition using titanium oxy-(1, 2 - pentadione) and zinc acetate without hazardous additives. The resulting composites were characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscope ...

  6. EFFECT OF LEAD ACETATE

    African Journals Online (AJOL)

    MICROSOFT

    A significant (P<0.05) increase was recorded in GPT, creatinine and uric acid levels ... chemical composition of the compound containing lead, ... their body weight. Each group comprised five chicks. Treatment. Groups A, B, C, D, E and F were treated once a day with lead acetate at a dose rate of 80, 120, 160, 200, 240 and ...

  7. Kinetics of phosphotungstic acid catalyzed oxidation of propan-1,3-diol and butan-1,4-diol by N-chlorosaccharin

    Directory of Open Access Journals (Sweden)

    Sanjay Kumar Singh

    2011-09-01

    Full Text Available The kinetic studies of N-chlorosaccharin (NCSA oxidation of propan-1,3-diol and butan-1,4-diol have been reported in presence of phophotungstic acid and in aqueous acetic acid medium. The reactions follow first-order in NCSA and one to zero order with respect to substrate and phosphotungstic acid. Increase in the concentration of added perchloric acid increases the rate of oxidation. A negative effect on the oxidation rate is observed for solvent whereas the ionic strength does not influence the rate of reaction. Addition of the reaction product, saccharin, exhibited retarding effect. Various activation parameters have been evaluated. The products of the reactions were identified as the corresponding aldehydes. A suitable scheme of mechanism consistent with the experimental results has been proposed.

  8. Kinetic α secondary deuterium isotope effects for O-ethyl S-phenyl benzaldehyde acetal hydrolysis

    International Nuclear Information System (INIS)

    Ferraz, J.P.; Cordes, E.H.

    1979-01-01

    The rate of hydrolysis of O-ethyl S-phenyl benzaldehyde acetal at 25 0 C in 20% dioxane--80% water is independent of pH over the range pH6-12; k/sub obsd/ = 1.9 x 10 -7 s -1 . Under more acidic conditions, the rate increases linearly with the activity of the hydrated proton; k 2 = 2.95 x 10 -2 M -1 s -1 . The kinetic α secondary deuterium isotope effect for acid-catalyzed hydrolysis of O-ethyl S-phenyl benzaldehyde acetal, measured at 25 0 C in 20% aqueous dioxane containing 0.05 M HCl, is k/sub H//k/sub D/ = 1.038 +- 0.008, a value consistent with a transition state in which the C--S bond is stretched rather little. In contrast, the corresponding isotope effect for the pH-independent hydrolysis of this substrate, measured at 42.5 0 C in 20% dioxane, is 1.13 +- 0.02, a value consistent with complete C--S bond cleavage in the transition state and rate-determining diffusion apart of the ion-pair formed as the initial intermediate, in accord with the suggestion of Jensen and Jencks. 1 figure, 4 tables

  9. Hydrothermal Liquefaction of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2010-12-10

    Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international

  10. Hydrothermal-acid treatment for effectual extraction of eicosapentaenoic acid (EPA)-abundant lipids from Nannochloropsis salina.

    Science.gov (United States)

    Lee, Ilgyu; Han, Jong-In

    2015-09-01

    Hydrothermal acid treatment, was adopted to extract eicosapentaenoic acid (EPA) from wet biomass of Nannochloropsis salina. It was found that sulfuric acid-based treatment increased EPA yield from 11.8 to 58.1 mg/g cell in a way that was nearly proportional to its concentration. Nitric acid exhibited the same pattern at low concentrations, but unlike sulfuric acid its effectiveness unexpectedly dropped from 0.5% to 2.0%. The optimal and minimal conditions for hydrothermal acid pretreatment were determined using a statistical approach; its maximum EPA yield (predicted: 43.69 mg/g cell; experimental: 43.93 mg/g cell) was established at a condition of 1.27% of sulfuric acid, 113.34 °C of temperature, and 36.71 min of reaction time. Our work demonstrated that the acid-catalyzed cell disruption, accompanied by heat, can be one potentially promising option for ω-3 fatty acids extraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 2-Phenylimidazolium acetate

    Directory of Open Access Journals (Sweden)

    Ji-Huan Yao

    2010-03-01

    Full Text Available There are two 2-phenylimidazole cations and two acetate anions in the asymmetric unit of the title molecular salt, C9H9N2+·C2H3O2−. The dihredral angles between the five- and six-membered rings are 5.50 (2 and 6.90 (2° in the two molecules. The structure is stabilized by N—H...O and weak C—H...O hydrogen-bonding interactions between the cations and anions, resulting in chains propagating in [110].

  12. Co3O4–ZnO hierarchical nanostructures by electrospinning and hydrothermal methods

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmed; Sheikh, Faheem A.; Barakat, Nasser A.M.

    2011-01-01

    , containing ZnO nanoparticles (ZnNPs), were then exploited as seeds to produce ZnO nanobranches using a specific hydrothermal technique. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the as-spun nanofibers and the calcined product. X-ray powder......A new hierarchical nanostructure that consists of cobalt oxide (Co3O4) and zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, cobalt acetate tetrahydrate and poly...

  13. Hydrothermal Growth of Polyscale Crystals

    Science.gov (United States)

    Byrappa, Kullaiah

    In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.

  14. Antibiofilm Properties of Acetic Acid

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup

    2014-01-01

    of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram......-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms....

  15. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  16. Drug-loaded Cellulose Acetate and Cellulose Acetate Butyrate Films ...

    African Journals Online (AJOL)

    The purpose of this research work was to evaluate the contribution of formulation variables on release properties of matrix type ocular films containing chloramphenicol as a model drug. This study investigated the use of cellulose acetate and cellulose acetate butyrate as film-forming agents in development of ocular films.

  17. Characterization of the Interunit Bonds of Lignin Oligomers Released by Acid-Catalyzed Selective Solvolysis of Cryptomeria japonica and Eucalyptus globulus Woods via Thioacidolysis and 2D-NMR.

    Science.gov (United States)

    Saito, Kaori; Kaiho, Atsushi; Sakai, Ryo; Nishimura, Hiroshi; Okada, Hitomi; Watanabe, Takashi

    2016-12-07

    Acid-catalyzed degradation of lignin in toluene containing methanol selectively yields C6-C2 lignin monomers and releases lignin oligomers, a potential raw feedstock for epoxy resins. We herein characterize the structures of the lignin oligomers by focusing on the changes in the interunit linkage types during solvolysis. The oligomeric lignin products were analyzed via thioacidolysis and 2D-HSQC-NMR. The results show that lignin oligomers ranging from monomers to tetramers are released through considerable cleavage of the β-O-4 linkages. The lignin oligomers from Cryptomeria japonica (softwood) mainly comprise β-5, β-1, and tetrahydrofuran β-β linkages, whereas Eucalyptus globulus (hardwood) yields oligomers rich in β-1 and syringaresinol β-β linkages. Both wood samples exhibit selective release of β-β dimers and a relative decrease in 5-5 and 4-O-5 bonds during solvolysis. The method presented for the separation of lignin oligomers without β-O-4 linkages and with linkages unique to each wood species will be useful for the production of lignin-based materials.

  18. (VI) oxide in acetic acid

    African Journals Online (AJOL)

    The oxidation of cyclohexene by chromium (VI) oxide in aqueous and acetic media was studied. The reaction products were analysed using infra red (IR) and gas chromatography coupled with mass (GC/MS) spectroscopy. The major products of the oxidation reaction in acetic acid medium were cyclohexanol, ...

  19. Hydrothermal pretreatment of coal

    Energy Technology Data Exchange (ETDEWEB)

    Ross, D.S.

    1989-12-21

    We have examined changes in Argonne Premium samples of Wyodak coal following 30 min treatment in liquid water at autogenous pressures at 150{degrees}, 250{degrees}, and 350{degrees}C. In most runs the coal was initially dried at 60{degrees}C/1 torr/20 hr. The changes were monitored by pyrolysis field ionization mass spectrometry (py-FIMS) operating at 2.5{degrees}C/min from ambient to 500{degrees}C. We recorded the volatility patterns of the coal tars evolved over that temperature range, and in all cases the tar yields were 25%--30% of the starting coal on mass basis. There was essentially no change after the 150{degrees}C treatment. Small increases in volatility were seen following the 250{degrees}C treatment, but major effects were seen in the 350{degrees} work. The tar quantity remained unchanged; however, the volatility increased so the temperature of half volatility for the as-received coal of 400{degrees}C was reduced to 340{degrees}C. Control runs with no water showed some thermal effect, but the net effect from the presence of liquid water was clearly evident. The composition was unchanged after the 150{degrees} and 250{degrees}C treatments, but the 350{degrees} treatment brought about a 30% loss of oxygen. The change corresponded to loss of the elements of water, although loss of OH'' seemed to fit the analysis data somewhat better. The water loss takes place both in the presence and in the absence of added water, but it is noteworthy that the loss in the hydrothermal runs occurs at p(H{sub 2}O) = 160 atm. We conclude that the process must involve the dehydration solely of chemically bound elements of water, the dehydration of catechol is a specific, likely candidate.

  20. Hydrothermal conversion of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, D.

    2009-09-03

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of water and high energy consumption that it requires can be avoided. The main focus of this work was HTC process aiming at production of transportation fuel intermediates. For this study, a new experimental technique using quartz capillary batch reactors has been developed, allowing determination of the yields of gas, liquid and solid products, and their subsequent analysis. The study was performed using glucose, a biomass model compound, and complex feedstocks, wood and pyrolysis oil. Important HTC features have been studied such as, undesired char formation, deoxygenation, and mechanism and kinetics of formation of different lumped product classes. Special attention is also given to products of the initial glucose decomposition and the kinetics of their formation. Complete mass and elemental balances obtained in this work significantly complement the literature findings on the reaction mechanism of HTC. Two distinct mechanisms of char formation are identified and two mechanisms of deoxygenation (dehydration and decarboxylation) are discussed. The observed trends in the product formation rates and yields are used to obtain an engineering reaction model for decomposition of glucose, which can be adapted for the use with complex feedstocks. Finally, a bench scale continuous reactor setup for HTC is proposed and several features of the setup have been tested separately in cold-flow, such as, feeding of biomass water slurries with a piston autoclave and a lifting fluidized bed, heat transfer, fluid bed operation and state of mixing of liquid and solid phases in continuous operations.

  1. Inert Reassessment Document for Amyl Acetate

    Science.gov (United States)

    Both acetates have a number of industrial uses such as solvents for lacquers, paints, and inks. Pharmaceutically, ethyl acetate is a flavoring aid and amyl acetate is used in extraction of penicillin.

  2. Hydrothermal processes and radionuclide transport

    International Nuclear Information System (INIS)

    Chapman, N.; McKinley, I.; Shea, M.; Smellie, J.

    1993-01-01

    The fourth objective of Pocos de Caldas Project is related to the hydrothermal processes expected to occur in some high-level waste repository concepts. Such processes are modelled with the same physical model used to analyse the hydrothermal processes which occur during the formation of the primary uranium mineralisation in the breccia pipes at the Osamu Utsumi mine. The temperature distribution, system dimensions and mechanisms of rock alteration show marked similarities to a United States repository case, although the fluid flux is much smaller in the case of the repository. (author) 1 fig

  3. Catalytic Combustion of Ethyl Acetate

    OpenAIRE

    ÖZÇELİK, Tuğba GÜRMEN; ATALAY, Süheyda; ALPAY, Erden

    2014-01-01

    The catalytic combustion of ethyl acetate over prepared metal oxide catalysts was investigated. CeO, Co2O3, Mn2O3, Cr2O3, and CeO-Co2O3 catalysts were prepared on monolith supports and they were tested. Before conducting the catalyst experiments, we searched for the homogeneous gas phase combustion reaction of ethyl acetate. According to the homogeneous phase experimental results, 45% of ethyl acetate was converted at the maximum reactor temperature tested (350 °C). All the prepare...

  4. Positron Spectroscopy of Hydrothermally Grown Actinide Oxides

    Science.gov (United States)

    2014-03-27

    POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS Edward C. Schneider...United States Government. AFIT-ENP-14-M-33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS...33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES Edward C. Schneider, BS Captain, USAF Approved

  5. Antibiofilm Properties of Acetic Acid

    Science.gov (United States)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup; Nielsen, Anne K.; Johansen, Helle Krogh; Homøe, Preben; Høiby, Niels; Givskov, Michael; Kirketerp-Møller, Klaus

    2015-01-01

    Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms. PMID:26155378

  6. Radioluminescence of solid ethyl acetate

    International Nuclear Information System (INIS)

    Kroh, J.; Plonka, A.; Wyszywacz, K.

    1977-01-01

    In the crystalline environment the reaction of thermalized electrons with ethyl acetate molecules is less effective than in glassy environment. Therefore more excess electrons are observed in crystalline ethyl acetate by isothermal luminescence and radiothermoluminescence. In the glassy environment other trapped species, like radical-anions CH 3 COOC 2 H 5 - or radicals CH 3 COOCHCH 3 , become reactive at lower temperatures than in the crystalline environment because of glass transition. (author)

  7. Geology of hydrothermal uranium deposits

    International Nuclear Information System (INIS)

    Korolev, K.G.; Belov, V.K.; Putilov, G.S.

    1983-01-01

    Geological characteristics of hydrothermal phosphorus-uranium deposits placed in sedimentary, igneous-sedimentary, metamorphic and intrusion formations are presented. Attention is paid to mineral composition, texture and structure of ores, their genesis, tectonics. Geochemical peculiarities of ores and age of molybdenum-uranium and uranium deposits are described. Geological criteria and prospecting features of uranium and uranium-molybdenum deposits are given

  8. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

  9. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA HAQ NAWAZ SHEIKH. Volume 39 Issue 4 August 2016 pp 943-952 ...

  10. Production of biofuels via hydrothermal conversion

    DEFF Research Database (Denmark)

    Biller, Patrick; Ross, Andrew

    2016-01-01

    Hydrothermal processing has evolved as an alternative processing technology for wet biomass and waste materials in recent years. Using hot-compressed water as a reaction medium at temperatures of 200–500°C, materials with increased energy density can be obtained. The technology is particularly......). Each of these hydrothermal routes results in energy densification by removal of oxygen to produce hydrochar (HTC), biocrude (HTL), or syngas (HTG). The process chemistry and reactions in hydrothermal media are described for each process. Suitable feedstocks and their considerations are reviewed...... suited for wet and waste materials as drying of the feedstock is not required. Hydrothermal processing is divided into three separate areas depending on reaction severity: hydrothermal carbonization (HTC, 180–280°C), hydrothermal liquefaction (HTL, 280–375°C), and hydrothermal gasification (HTG, >350°C...

  11. 21 CFR 173.228 - Ethyl acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl acetate. 173.228 Section 173.228 Food and..., Lubricants, Release Agents and Related Substances § 173.228 Ethyl acetate. Ethyl acetate (CAS Reg. No. 141-78... the specifications of the Food Chemicals Codex, 1 (Ethyl Acetate; p. 372, 3d Ed., 1981), which are...

  12. 27 CFR 21.107 - Ethyl acetate.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ethyl acetate. 21.107....107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by...); for incorporation by reference, see § 21.6(b).) When 100 ml of ethyl acetate are distilled by this...

  13. Acetate Kinase Isozymes Confer Robustness in Acetate Metabolism

    DEFF Research Database (Denmark)

    Chan, Siu Hung Joshua; Nørregaard, Lasse; Solem, Christian

    2014-01-01

    Acetate kinase (ACK) (EC no: 2.7.2.1) interconverts acetyl-phosphate and acetate to either catabolize or synthesize acetyl-CoA dependent on the metabolic requirement. Among all ACK entries available in UniProt, we found that around 45% are multiple ACKs in some organisms including more than 300...... species but surprisingly, little work has been done to clarify whether this has any significance. In an attempt to gain further insight we have studied the two ACKs (AckA1, AckA2) encoded by two neighboring genes conserved in Lactococcus lactis (L. lactis) by analyzing protein sequences, characterizing...

  14. Hydrothermal synthesis of nanostructured titania

    International Nuclear Information System (INIS)

    Yoshito, Walter Kenji; Ferreira, Nildemar A.M.; Rumbao, Ana Carolina S. Coutinho; Lazar, Dolores R.R.; Ussui, Valter

    2009-01-01

    Titania ceramics have many applications due to its surface properties and, recently, its nanostructured compounds, prepared by hydrothermal treatments, have been described to improve these properties. In this work, commercial titanium dioxide was treated with 10% sodium hydroxide solution in a pressurized reactor at 150°C for 24 hours under vigorous stirring and then washed following two different procedures. The first one consisted of washing with water and ethanol and the second with water and hydrochloric acid solution (1%). Resulting powders were characterized by X-ray diffraction, N 2 gas adsorption and field emission gun scanning and transmission electronic microscopy. Results showed that from an original starting material with mainly rutile phase, both anatase and H 2 Ti 3 O 7 phase could be identified after the hydrothermal treatment. Surface area of powders presented a notable increase of one order of magnitude and micrographs showed a rearrangement on the microstructure of powders. (author)

  15. Hydrothermal synthesis of nanostructured titania

    International Nuclear Information System (INIS)

    Yoshito, W.K.; Ferreira, N.A.M.; Lazar, D.R.R.; Ussui, V.; Rumbao, A.C.S.

    2011-01-01

    Titania ceramics have many applications due to its surface properties and, recently, its nanostructured compounds, prepared by hydrothermal treatments, have been described to improve these properties. In this work, commercial titanium dioxide was treated with 10% sodium hydroxide solution in a pressurized reactor at 150 deg C for 24 hours under vigorous stirring and then washed following two different procedures. The first one consisted of washing with water and ethanol and the second with water and hydrochloric acid solution (1%). Resulting powders were characterized by X-ray diffraction, N 2 gas adsorption and field emission gun scanning and transmission electronic microscopy. Results showed that from an original starting material with mainly rutile phase, both anatase and H 2 Ti 3 O 7 phase could be identified after the hydrothermal treatment. Surface area of powders presented a notable increase of one order of magnitude and micrographs showed a rearrangement on the microstructure of powders. (author)

  16. Effect of preparation procedure on the formation of nanostructuredceria–zirconia mixed oxide catalysts for ethyl acetate oxidation:Homogeneous precipitation with urea vs template-assistedhydrothermal synthesis

    Czech Academy of Sciences Publication Activity Database

    Tsoncheva, T.; Ivanova, R.; Henych, Jiří; Dimitrov, M.; Kormunda, M.; Kovacheva, D.; Scotti, N.; Dal Santo, V.; Štengl, Václav

    2015-01-01

    Roč. 502, JUL (2015), s. 418-432 ISSN 0926-860X Institutional support: RVO:61388980 Keywords : Ceria–zirconia mixed oxides * Template -assisted hydrothermal method * Urea hydrolysis * Ethyl acetate oxidationa Subject RIV: CA - Inorganic Chemistry Impact factor: 4.012, year: 2015

  17. Analysis of proteins responsive to acetic acid in Acetobacter: molecular mechanisms conferring acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro

    2008-06-30

    Acetic acid bacteria are used for industrial vinegar production because of their remarkable ability to oxidize ethanol and high resistance to acetic acid. Although several molecular machineries responsible for acetic acid resistance in acetic acid bacteria have been reported, the entire mechanism that confers acetic acid resistance has not been completely understood. One of the promising methods to elucidate the entire mechanism is global analysis of proteins responsive to acetic acid by two-dimensional gel electrophoresis. Recently, two proteins whose production was greatly enhanced by acetic acid in Acetobacter aceti were identified to be aconitase and a putative ABC-transporter, respectively; furthermore, overexpression or disruption of the genes encoding these proteins affected acetic acid resistance in A. aceti, indicating that these proteins are involved in acetic acid resistance. Overexpression of each gene increased acetic acid resistance in Acetobacter, which resulted in an improvement in the productivity of acetic acid fermentation. Taken together, the results of the proteomic analysis and those of previous studies indicate that acetic acid resistance in acetic acid bacteria is conferred by several mechanisms. These findings also provide a clue to breed a strain having high resistance to acetic acid for vinegar fermentation.

  18. Radiation sterilization of hydrocortisone acetate

    International Nuclear Information System (INIS)

    Charef, A.; Boussaha, A.

    1989-09-01

    The feasibility of using high energy ionizing radiation for the sterilization of hydrocortisone acetate was investigated. Hydrocortisone acetate in the form of powder was exposed to different dose levels of gamma radiation using a Cobalt-60 source. The irradiated samples were examined by various physico-chemical techniques in order to detect possible radiolysis products. It was of interest to know if one could insure sterility and retain biological properties of the drug by suitable choice of radiation dose. The results showed that a 10 KGy radiation dose causes no change in the physico-chemical properties of the drug and is sufficient to obtain contaminant-free product

  19. 5-(Chloromethylquinolin-8-yl acetate

    Directory of Open Access Journals (Sweden)

    Ling-Qian Kong

    2008-08-01

    Full Text Available The title compound, C12H10ClNO2, crystallizes with two independent molecules in the asymmetric unit; these are approximate mirror images of each other. In each molecule, the chloromethyl and acetate groups lie on the same side of the quinoline ring system, with dihedral angles between the ring plane and the plane of the acetate group of 82.0 (1 and −79.2 (1°. The C—C—C—Cl torsion angles for the chloromethyl groups of the two molecules are 80.9 (2 and −83.1 (2°.

  20. Desmopressin Acetate in Intracranial Haemorrhage

    Directory of Open Access Journals (Sweden)

    Thomas Kapapa

    2014-01-01

    Full Text Available Introduction. The secondary increase in the size of intracranial haematomas as a result of spontaneous haemorrhage or trauma is of particular relevance in the event of prior intake of platelet aggregation inhibitors. We describe the effect of desmopressin acetate as a means of temporarily stabilising the platelet function. Patients and Methods. The platelet function was analysed in 10 patients who had received single (N=4 or multiple (N=6 doses of acetylsalicylic acid and 3 patients (control group who had not taken acetylsalicylic acid. All subjects had suffered intracranial haemorrhage. Analysis was performed before, half an hour and three hours after administration of desmopressin acetate. Statistical analysis was performed by applying a level of significance of P≤0.05. Results. (1 Platelet function returned to normal 30 minutes after administration of desmopressin acetate. (2 The platelet function worsened again after three hours. (3 There were no complications related to electrolytes or fluid balance. Conclusion. Desmopressin acetate can stabilise the platelet function in neurosurgical patients who have received acetylsalicylic acid prior to surgery without causing transfusion-related side effects or a loss of time. The effect is, however, limited and influenced by the frequency of drug intake. Further controls are needed in neurosurgical patients.

  1. Hydrothermal synthesis of cubic boron nitride crystals

    International Nuclear Information System (INIS)

    Yu Meiyan; Cui Deliang; Kai Li; Yin Yansheng; Wang Qilong; Lei Chu

    2005-01-01

    Cubic boron nitride (cBN) crystals have been successfully synthesized by in situ hydrothermal method. In order to obtain cBN pure phase crystals, two comparative experiments were carried out. The experimental results indicated that compared to one-step in situ hydrothermal method, multi-step in situ hydrothermal method was beneficial to the synthesis of cBN. It is believed that the multi-step in situ hydrothermal method is the optimal route to synthesize pure cBN bulk crystals

  2. Resource recovery from waste LCD panel by hydrothermal transformation of polarizer into organic acids.

    Science.gov (United States)

    Li, Feng; Bai, Lan; He, Wenzhi; Li, Guangming; Huang, Juwen

    2015-12-15

    Based on the significant advantages of hydrothermal technology, it was applied to treat polarizer from the waste LCD panel with the aim of transforming it into organic acids (mainly acetic acid and lactic acid). Investigation was done to evaluate the effects of different factors on yields of organic acids, including the reaction temperature, reaction time and H2O2 supply, and the degradation process of polarizer was analyzed. Liquid samples were analyzed by GC/MS and HPLC, and solid-phase products were characterized by SEM and FTIR. Results showed that at the condition of temperature 300 °C and reaction time 5 min, the organic materials reached its highest conversion rate of 71.47% by adding 0.2 mL H2O2 and acetic acid was dominant in the products of organic acids with the yield of 6.78%. When not adding H2O2 to the system, the yields of lactic and acetic acid were respectively 4.24% and 3.80% at a nearly equal degree, they are suitable for esterification to form ethyl lactate instead of separating them for this case. In the hydrothermal process, polarizer was first decomposed to monosaccharides, alkane, etc., and then furfural and acids are produced with further decomposition. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Modeling Hydrothermal Activity on Enceladus

    Science.gov (United States)

    Stamper, T., Jr.; Farough, A.

    2017-12-01

    Cassini's mass spectrometer data and gravitational field measurements imply water-rock interactions around the porous core of Enceladus. Using such data we characterize global heat and fluid transport properties of the core and model the ongoing hydrothermal activity on Enceladus. We assume that within the global ocean beneath the surface ice, seawater percolates downward into the core where it is heated and rises to the oceanfloor where it emanates in the form of diffuse discharge. We utilize the data from Hsu et al., [2015] with models of diffuse flow in seafloor hydrothermal systems by Lowell et al., [2015] to characterize the global heat transport properties of the Enceladus's core. Based on direct observations the gravitational acceleration (g) is calculated 0.123 m s-2. We assume fluid's density (ρ) is 10­3 kg m-3 and the specific heat of the fluid (cf) is 4000 Jkg-1 °C-1. From these values effective thermal diffusivity (a*) is calculated as 10­-6 m2 s-1. We also assume the coefficient of thermal expansion of fluid (αf) and the kinematic viscosity of fluid (ν) to be 10-4 °C-1 and 10­-6 m2 s-1 respectively. The estimated Rayleigh number (Ra) ranges between 0.11-2468.0, for core porosity (φ) of 5-15%, permeability (k) between 10-12-10-8 m2 and temperature between 90-200 °C and the depth of fluid circulation of 100 m. High values of Rayleigh number, cause vigorous convection within the core of Enceladus. Numerical modeling of reactive transport in multicomponent, multiphase systems is required to obtain a full understanding of the characteristics and evolution of the hydrothermal system on Enceladus, but simple scaling laws can provide insight into the physics of water-rock interactions.

  4. Biofiltration of ethyl acetate and amyl acetate using a composite bead biofilter.

    Science.gov (United States)

    Chan, Wu-Chung; Su, Mei-Qi

    2008-11-01

    Biodegradation kinetic behaviors of ethyl acetate and amyl acetate in a composite bead biofilter were investigated. The composite bead was the spherical PVA/peat/KNO3/GAC composite bead which was prepared in our previous works. Both microbial growth rate and biochemical reaction rate were inhibited at higher inlet concentration. For the microbial growth process, the microbial growth rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The degree of inhibitive effect was almost the same for ethyl acetate and amyl acetate in this concentration range. The half-saturation constant Ks values of ethyl acetate and amyl acetate were 16.26 and 12.65ppm, respectively. The maximum reaction rate Vm values of ethyl acetate and amyl acetate were 4.08 and 3.53gCh(-1)kg(-1) packed material, respectively. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The inhibitive effect for ethyl acetate was more pronounced than that for AA in this concentration range. The maximum elimination capacity of ethyl acetate and amyl acetate were 82.3 and 37.93gCh(-1)m(-3) bed volume, respectively. Ethyl acetate degraded by microbial was easier than amyl acetate did.

  5. 21 CFR 184.1185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

    ... CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific...-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be...

  6. Hydrothermal performance of catalyst supports

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.; Marshall, Christopher L.; Libera, Joseph A.; Dumesic, James A.; Pagan-Torres, Yomaira J.

    2018-04-10

    A high surface area catalyst with a mesoporous support structure and a thin conformal coating over the surface of the support structure. The high surface area catalyst support is adapted for carrying out a reaction in a reaction environment where the thin conformal coating protects the support structure within the reaction environment. In various embodiments, the support structure is a mesoporous silica catalytic support and the thin conformal coating comprises a layer of metal oxide resistant to the reaction environment which may be a hydrothermal environment.

  7. Solubility determination and thermodynamic models for dehydroepiandrosterone acetate in mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol) and (ethyl acetate + isopropanol)

    International Nuclear Information System (INIS)

    Cheng, Chao; Cong, Yang; Du, Cunbin; Wang, Jian; Yao, Ganbing; Zhao, Hongkun

    2016-01-01

    Highlights: • Solubilities of dehydroepiandrosterone acetate in mixed solvents were determined. • The measured solubility data were correlated with three thermodynamic models. • The standard dissolution enthalpies of dehydroepiandrosterone acetate were calculated. - Abstract: The solubility of dehydroepiandrosterone acetate in binary solvent mixtures of (ethyl acetate + methanol), (ethyl acetate + ethanol) and (ethyl acetate + isopropanol) was determined experimentally by using an isothermal dissolution equilibrium method within the temperature range from (273.15 to 313.15) K under atmosphere pressure (101.1 kPa). The solubility of dehydroepiandrosterone acetate increases with increasing temperature and mass fraction of ethyl acetate in each binary system. At the same temperature and mass fraction of ethyl acetate, the solubility of dehydroepiandrosterone acetate was greater in (ethyl acetate + isopropanol) than in the other two mixed solvents. The measured solubility values were correlated with the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model, and modified Apelblat-Jouyban-Acree model. The Jouyban-Acree model was proven to give better representation for the experimental solubility, which provided the lowest relative average deviation and root-mean-square deviation (0.49 × 10 −2 and 0.97 × 10 −4 for ethyl acetate + methanol, 0.44 × 10 −2 and 0.82 × 10 −4 for ethyl acetate + ethanol, and 0.92 × 10 −2 and 3.05 × 10 −4 for ethyl acetate + isopropanol, respectively). Based on the solubility values obtained, the standard dissolution enthalpies for the dissolution process were computed. The dissolution process of dehydroepiandrosterone acetate in these mixed solvents was endothermic. The experimental solubility and the equations presented in the present work can be employed as essential data and models in the practical process for production and purification of dehydroepiandrosterone acetate.

  8. rights reserved Geophysical Identification of Hydrothermally Altered ...

    African Journals Online (AJOL)

    ADOWIE PERE

    the pole to the magnetic data aided in mapping of various hydrothermally altered structures that may favour gold mineralisation. The interpretation of the aero data set has enhanced a lot of ... water serves as a concentrating, transporting and depositing agent through faults (structures) to the earth's surface. Hydrothermal ...

  9. Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

    Science.gov (United States)

    Shi, Weidong; Song, Shuyan; Zhang, Hongjie

    2013-07-07

    Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

  10. Geophysical Identification of Hydrothermally Altered Structures That ...

    African Journals Online (AJOL)

    This research study uses geophysical method (aeromagnetic) to identify hydrothermally altered structures which favour the inflow of hydrothermal fluid that usually brings about gold mineralisation in Egbe-Isanlu Schist Belt Area, North Central Nigeria. The application of data enhancement filtering algorithm such as ...

  11. Whole Algae Hydrothermal Liquefaction Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, M.; Davis, R.; Jones, S.

    2013-03-01

    This technology pathway case investigates the feasibility of using whole wet microalgae as a feedstock for conversion via hydrothermal liquefaction. Technical barriers and key research needs have been assessed in order for the hydrothermal liquefaction of microalgae to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

  12. 21 CFR 582.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is generally...

  13. Pallidol hexaacetate ethyl acetate monosolvate

    Directory of Open Access Journals (Sweden)

    Qinyong Mao

    2013-07-01

    Full Text Available The entire molecule of pallidol hexaacetate {systematic name: (±-(4bR,5R,9bR,10R-5,10-bis[4-(acetyloxyphenyl]-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-1,3,6,8-tetrayl tetraacetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate molecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009. Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexaacetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å is 54.73 (6°, indicating a significant fold in the molecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carboxy—C—C torsion angles = −70.24 (14, −114.43 (10 and −72.54 (13°]. In the crystal, a three-dimensional architecture is sustained by C—H...O interactions which encompass channels in which the disordered ethyl acetate molecules reside.

  14. Antibiofilm Properties of Acetic Acid

    OpenAIRE

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup; Nielsen, Anne K.; Johansen, Helle Krogh; Homøe, Preben; Høiby, Niels; Givskov, Michael; Kirketerp-Møller, Klaus

    2015-01-01

    Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacteri...

  15. Arctic Ocean: hydrothermal activity on Gakkel Ridge.

    Science.gov (United States)

    Jean-Baptiste, Philippe; Fourré, Elise

    2004-03-04

    In the hydrothermal circulation at mid-ocean ridges, sea water penetrates the fractured crust, becomes heated by its proximity to the hot magma, and returns to the sea floor as hot fluids enriched in various chemical elements. In contradiction to earlier results that predict diminishing hydrothermal activity with decreasing spreading rate, a survey of the ultra-slowly spreading Gakkel Ridge (Arctic Ocean) by Edmonds et al. and Michael et al. suggests that, instead of being rare, the hydrothermal activity is abundant--exceeding by at least a factor of two to three what would be expected by extrapolation from observation on faster spreading ridges. Here we use helium-3 (3He), a hydrothermal tracer, to show that this abundance of venting sites does not translate, as would be expected, into an anomalous hydrothermal 3He output from the ridge. Because of the wide implications of the submarine hydrothermal processes for mantle heat and mass fluxes to the ocean, these conflicting results call for clarification of the link between hydrothermal activity and crustal production at mid-ocean ridges.

  16. Dynamics of the Yellowstone hydrothermal system

    Science.gov (United States)

    Hurwitz, Shaul; Lowenstern, Jacob B.

    2014-01-01

    The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a hydrothermal system that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and hydrothermal explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the hydrothermal system have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the hydrothermal system. Specific advances include more refined geophysical images of the magmatic system, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of hydrothermal explosions and their relation to glacial cycles, defining possible links between hydrothermal activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive hydrothermal activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.

  17. A thermoelectric cap for seafloor hydrothermal vents

    International Nuclear Information System (INIS)

    Xie, Yu; Wu, Shi-jun; Yang, Can-jun

    2016-01-01

    Highlights: • We developed a thermoelectric cap (TC) to harvest hydrothermal energy. • The TC was deployed at a hydrothermal vent site near Kueishantao islet, Taiwan. • The TC monitored the temperature of the hydrothermal fluids during the field test. • The TC could make the thermal energy of hydrothermal fluids a viable power source. - Abstract: Long-term in situ monitoring is crucial to seafloor scientific investigations. One of the challenges of operating sensors in seabed is the lifespan of the sensors. Such sensors are commonly powered by batteries when other alternatives, such as tidal or solar energy, are unavailable. However, the batteries have a limited lifespan and must be recharged or replaced periodically, which is costly and impractical. A thermoelectric cap, which harvests the thermal energy of hydrothermal fluids through a conduction pipe and converts the heat to electrical energy by using thermoelectric generators, was developed to avoid these inconveniences. The thermoelectric cap was combined with a power and temperature measurement system that enables the thermoelectric cap to power a light-emitting diode lamp, an electronic load (60 Ω), and 16 thermocouples continuously. The thermoelectric cap was field tested at a shallow hydrothermal vent site near Kueishantao islet, which is located offshore of northeastern Taiwan. By using the thermal gradient between hydrothermal fluids and seawater, the thermoelectric cap obtained a sustained power of 0.2–0.5 W during the field test. The thermoelectric cap successfully powered the 16 thermocouples and recorded the temperature of the hydrothermal fluids during the entire field test. Our results show that the thermal energy of hydrothermal fluids can be an alternative renewable power source for oceanographic research.

  18. Seawater bicarbonate removal during hydrothermal circulation

    Science.gov (United States)

    Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

    2013-12-01

    High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

  19. Powering hydrothermal activity on Enceladus

    Science.gov (United States)

    Tobie, Gabriel; Choblet, Gael; Sotin, Christophe; Behounkova, Marie; Cadek, Ondrej; Postberg, Frank; Soucek, Ondrej

    2017-04-01

    A series of evidence gathered by the Cassini spacecraft indicates that the intense activity at the South Pole of Saturn's moon Enceladus is related to a subsurface salty water reservoir associated with seafloor hydrothermal activity (Hsu et al. 2015, Waite et al. 2017). The observation of an elevated libration implies that this reservoir is global with a thin ice shell (20-25 km in average (Thomas et al. 2016) and friction in the porous core and simulate heat transport by water flow for core porosities consistent with Cassini gravity data (Iess et al. 2014). We demonstrate that, for effective viscosity and permeability values typical of water-saturated terrestrial rock analogues, more than 20 GW can be generated in the core, which can maintain a global liquid ocean and power hydrothermal activity at the seafloor. By performing 3D simulations of water flow in a tidally-heated porous rock matrix, we show that heat is extracted from the core in the form of focused outflows of hot water (> 90 °C) mostly in the polar regions, explaining strongly localized ice shell thinning. Owing to strong dissipation in Saturn (Lainey et al. 2017), we show that circulation of hot waters in the core may last at least 20-25 million years and that 10 to 100% of the oceanic volume may be processed in the core at temperature higher than 90°C on this timescale. Whether this has been sufficient for the emergence of life can be explored by future spacecraft missions (Mitri et al., this meeting; Lunine et al. 2017).

  20. Hydrothermal processing of actinide contaminated organic wastes

    International Nuclear Information System (INIS)

    Worl, A.; Buelow, S.J.; Le, L.A.; Padilla, D.D.; Roberts, J.H.

    1997-01-01

    Hydrothermal oxidation is an innovative process for the destruction of organic wastes, that occurs above the critical temperature and pressure of water. The process provides high destruction and removal efficiencies for a wide variety of organic and hazardous substances. For aqueous/organic mixtures, organic materials, and pure organic liquids hydrothermal processing removes most of the organic and nitrate components (>99.999%) and facilitates the collection and separation of the actinides. We have designed, built and tested a hydrothermal processing unit for the removal of the organic and hazardous substances from actinide contaminated liquids and solids. Here we present results for the organic generated at the Los Alamos National Laboratory Plutonium Facility

  1. The kinetics of inhibitor production resulting from hydrothermal deconstruction of wheat straw studied using a pressurised microwave reactor.

    Science.gov (United States)

    Ibbett, Roger; Gaddipati, Sanyasi; Greetham, Darren; Hill, Sandra; Tucker, Greg

    2014-03-29

    The use of a microwave synthesis reactor has allowed kinetic data for the hydrothermal reactions of straw biomass to be established from short times, avoiding corrections required for slow heating in conventional reactors, or two-step heating. Access to realistic kinetic data is important for predictions of optimal reaction conditions for the pretreatment of biomass for bioethanol processes, which is required to minimise production of inhibitory compounds and to maximise sugar and ethanol yields. The gravimetric loss through solubilisation of straw provided a global measure of the extent of hydrothermal deconstruction. The kinetic profiles of furan and lignin-derived inhibitors were determined in the hydrothermal hydrolysates by UV analysis, with concentrations of formic and acetic acid determined by HPLC. Kinetic analyses were either carried out by direct fitting to simple first order equations or by numerical integration of sequential reactions. A classical Arrhenius activation energy of 148 kJmol-1 has been determined for primary solubilisation, which is higher than the activation energy associated with historical measures of reaction severity. The gravimetric loss is primarily due to depolymerisation of the hemicellulose component of straw, but a minor proportion of lignin is solubilised at the same rate and hence may be associated with the more hydrophilic lignin-hemicellulose interface. Acetic acid is liberated primarily from hydrolysis of pendant acetate groups on hemicellulose, although this occurs at a rate that is too slow to provide catalytic enhancement to the primary solubilisation reactions. However, the increase in protons may enhance secondary reactions leading to the production of furans and formic acid. The work has suggested that formic acid may be formed under these hydrothermal conditions via direct reaction of sugar end groups rather than furan breakdown. However, furan degradation is found to be significant, which may limit ultimate

  2. Hydrothermal system of Long Valley caldera, California

    Energy Technology Data Exchange (ETDEWEB)

    Sorey, M.L.; Lewis, R.E.; Olmsted, F.H.

    1978-01-01

    The geologic and hydrologic setting of the hydrothermal system are described. The geochemical and thermal characteristics of the system are presented. A mathematical model of the Long Valley caldera is analyzed. (MHR)

  3. Hydrothermal industrialization: direct heat development. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-01

    A description of hydrothermal resources suitable for direct applications, their associated temperatures, geographic distribution and developable capacity are given. An overview of the hydrothermal direct-heat development infrastructure is presented. Development activity is highlighted by examining known and planned geothermal direct-use applications. Underlying assumptions and results for three studies conducted to determine direct-use market penetration of geothermal energy are discussed.

  4. 21 CFR 184.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation of...

  5. Thermodynamics of Organic Compound Alteration in Hydrothermal Systems

    Science.gov (United States)

    Shock, E. L.

    2005-12-01

    Organic compounds enter hydrothermal systems through infiltrating surface waters, zones of microbial productivity in the subsurface, extracts of organic matter in surrounding host rocks, and abiotic synthesis. Owing to variations in pH, oxidation state, composition, temperature, and pressure throughout the changing pathways of fluid migration over the duration of the system, organic compounds from all of these sources are introduced to conditions where their relative stabilities and reactivities can be dramatically transformed. If those transformations were predictable, then the extent to which organic alteration reactions have occurred could be used to reveal flowpaths and histories of hydrothermal systems. Speciation and mass transfer calculations permit some insight into the underlying thermodynamic driving forces that result in organic compound alteration. As an example, the speciation of many geochemist's canonical organic matter: CH2O depends strongly on oxidation state, temperature, and total concentration of dissolved organic matter. Calculations show that at oxidation states buffered by iron-bearing mineral assemblages, organic acids dominate the speciation of CH2O throughout hydrothermal systems, with acetic acid (itself equivalent to 2 CH2O by bulk composition) and propanoic acid generally the most abundant compounds. However, at more reduced conditions, which may prevail in organic-rich iron-poor sediments, the drive is to form ketones and especially alcohols at the expense of organic acids. The distribution of organic carbon among the various members of these compound classes is strongly dependent on the total concentration of dissolved organic matter. As an example, at a bulk concentration equivalent to average dissolved organic matter in seawater (45μm), the dominant alcohols at 100°C are small compounds like ethanol and 1-propanol. In contrast, at a higher bulk concentration of 500μm, there is a drive to shift large percentages of dissolved

  6. Kinetics and mechanism of the general-acid-catalyzed ring-closure of the malondialdehyde-DNA adduct, N2-(3-oxo-1-propenyl)deoxyguanosine (N2OPdG-), to 3-(2'-Deoxy-beta-D-erythro-pentofuranosyl)pyrimido[1,2-alpha]purin- 10(3H)-one (M1dG).

    Science.gov (United States)

    Riggins, James N; Pratt, Derek A; Voehler, Markus; Daniels, J Scott; Marnett, Lawrence J

    2004-09-01

    3-(2'-Deoxy-beta-D-erythro-pentofuranosyl)pyrimido[1,2-alpha]purin-10(3H)-one (M1dG) is the major product of the reaction of deoxyguanosine with malondialdehyde (MDA). M1dG blocks replication by DNA polymerases in vitro and is mutagenic in vivo. M1dG reacts with hydroxide to form the N2-(3-oxo-1-propenyl)deoxyguanosine anion (N2OPdG-). This reaction is pH-dependent and reverses under neutral and acidic conditions to form M1dG. Here we describe the kinetics and mechanism of the ring-closure reaction in both the nucleoside and oligonucleotides. Kinetic analysis of absorbance and fluorescence changes demonstrates that ring-closure is biphasic, leading to the rapid formation of an intermediate that slowly converts to M1dG in a general-acid-catalyzed reaction. The dependence of the rate of the rapid phase on pH reveals the pKa for protonated N2OPdG is 6.9. One-dimensional 1H NMR and DQF-COSY experiments identified two distinct intermediates, N2OPdG-H and 8-hydroxy-6,7-propenodeoxyguanosine (HO-Prene-dG), that are formed upon acidification of N2OPdG-. Characterization of ring-closure in single-stranded and in melted duplex oligonucleotides shows M1dG formation is also acid-catalyzed in single-stranded oligonucleotides and that the denaturation of an oligonucleotide duplex enhances ring-closure. This work details the complexity of ring-closure in the nucleoside and oligonucleotides and provides new insight into the role of duplex DNA in catalyzing ring-opening and ring-closing of M1dG and N2OPdG. Copyright 2004 American Chemical Society

  7. Positron scattering from vinyl acetate

    International Nuclear Information System (INIS)

    Chiari, L; Brunger, M J; Zecca, A; Blanco, F; García, G

    2014-01-01

    Using a Beer–Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C 4 H 6 O 2 ) in the incident positron energy range 0.15–50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1–1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ∼2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect. (paper)

  8. Synthesis and Electrochemical Performance of LiMnPO4 by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Daichi Fujimoto

    2014-01-01

    Full Text Available LiMnPO4 with olivinestructure which is the promising candidate for high voltage cathode material was synthesized by hydrothermal method. In order to synthesize high purity and well-defined LiMnPO4, several precursors for Li, Mn, and P sources and hydrothermal reaction parameters including temperature and [H2O]/[Mn] value are optimized. By analyzing the structure, Mn valence, morphology, and chemical ratio via XRD, XPS, Raman, SEM, and ICP LiMnPO4 synthesized from manganese acetate tetrahydrate have single phase of LiMnPO4 without impurity and showed charge and discharge reaction caused by Mn2+/Mn3+ redox. Specific capacity of synthesized LiMnPO4 grew up during cycling. Moreover, when hydrothermal temperature was set at 150°C and [H2O]/[Mn] value was set at 15, discharge capacity as high as 70 mAh/g was obtained at 1/20  C rate.

  9. Manufacturing Ethyl Acetate From Fermentation Ethanol

    Science.gov (United States)

    Rohatgi, Naresh K.; Ingham, John D.

    1991-01-01

    Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

  10. Double Intramolecular Transacetalization of Polyhydroxy Acetals: Synthesis of Conformationally-Restricted 1,3-Dioxanes with Axially-Oriented Phenyl Moiety

    Directory of Open Access Journals (Sweden)

    Samuel Asare-Nkansah

    2016-11-01

    Full Text Available The synthesis of conformationally-restricted 1,3-dioxanes with a phenyl moiety fixed in an axial orientation at the acetalic center is described. Starting with diethyl 3-hydroxyglutarate (15, benzaldehyde acetal 12a and acetophenone ketal 12b bearing a protected 1,3,5-trihydroxypentyl side chain in the o-position were prepared. The first acid-catalyzed intramolecular transacetalization gave a mixture of diastereomeric 2-benzofurans 18 (ratio of diastereomers 2:2:1:1. After OH group deprotection, the second intramolecular transacetalization afforded tricyclic alcohol 14a (2-(1,5-epoxy-1,3,4,5-tetrahydro-2-benzoxepin-3-yl]ethan-1-ol. Analogous cyclizations led to the corresponding silyl ether 22a (19% and azide 23a (13%. Whereas tricyclic alcohol 14a was obtained as a 1:1 mixture of diastereomers, the silyl ether 22a and the azide 23a afforded only one diastereomer. This observation indicates a faster cyclization of the minor diastereomers providing the thermodynamically-favored compounds with equatorially-oriented substituents in the 3-position of the tricyclic 1,5-epoxy-2-benzoxepine system. In general, acetophenone-derived ketalic compounds (b-series required very mild reaction conditions and gave lower yields than the corresponding acetalic compounds (a-series.

  11. Hydrothermal growth of titania nanowires for SAW device sensing area

    Science.gov (United States)

    Rosydi Zakaria, Mohd; Ayub, Sh. Nadzirah S.; Hafiz Ismail, Mohd; Johari, Shazlina; Hashim, Uda

    2017-11-01

    Synthesis of titania or titanium dioxide (TiO2) is attracted to energy and environmental applications. Here, the growth of nanostructure TiO2 nanowires on Si (100) substrates by using the two-step method. Different seed layers of TiO2 were deposited by spin coating and annealing, followed by the growth of TiO2 nanowires by using the hydrothermal method. The sol-gel technique was used in preparing the TiO2 solution for the thin film deposition purpose. Acetic acid, hydrochloric acid and tris (2-aminoethyl) amine were used as a stabilizer to synthesize three different TiO2 seed layers. The aim of this study was to understand the role of polycrystalline size on thin film towards the diameter of nanowires grown as a sensing area in Surface Acoustic Wave (SAW) Biosensor. The morphology and structure of the thin film and TiO2 nanowires were characterized using X-Ray diffraction (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM).

  12. Peptide synthesis in early earth hydrothermal systems

    Science.gov (United States)

    Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.

    2009-01-01

    We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made hydrothermal reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol-1) exergonic shift. In contrast to previous hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.

  13. An experimental determination of ferrous chloride and acetate complexation in aqueous solutions to 300°C

    Science.gov (United States)

    Palmer, Donald A.; Hyde, K. E.

    1993-04-01

    The formation of the monochloroiron(II) complex, FeCl +, was studied potentiometrically from 125 to 295°C at 25 degree intervals at one molal ionic strength in aqueous solutions containing acetic acid, sodium acetate, and sodium trifluoromethanesulfonate. In this method, competition between chloride and acetate ions for the ferrous cation resulted in a change in solution pH, which in turn was monitored in situ in a hydrogen-electrode, concentration cell. A simple empirical approach was used to extrapolate these formation quotients to infinite dilution. The resulting constants proved to be in excellent agreement with previous spectrophotometric results obtained from 25 to 200°C. Thus, the present study confirms the validity of the conclusions made based on these earlier data concerning the solubility of Fe-containing minerals in hydrothermal brines. Formation constants at infinite dilution for FeCl + are compared with the stability of ferrous acetate and hydroxide complexes. The original potentiometric titration data for ferrous acetate complex formation were combined in a new fit with values determined from the present study at unit ionic strength. Two empirical treatments (namely the isocoulombic method and the temperature/water density function) were considered for fitting and extrapolating the infinite dilution formation constants to 350°C.

  14. Ulipristal acetate in emergency contraception.

    Science.gov (United States)

    Goldstajn, Marina Sprem; Baldani, Dinka Pavicić; Skrgatić, Lana; Radaković, Branko; Vrbić, Hrvoje; Canić, Tomislav

    2014-03-01

    Despite the widespread availability of highly effective methods of contraception, unintended pregnancy is common. Unplanned pregnancies have been linked to a range of health, social and economic consequences. Emergency contraception reduces risk of pregnancy after unprotected intercourse, and represents an opportunity to decrease number of unplanned pregnancies and abortions. Emergency contraception pills (ECP) prevent pregnancy by delaying or inhibiting ovulation, without interfering with post fertilization events. If pregnancy has already occurred, ECPs will not be effective, therefore ECPs are not abortificants. Ulipristal acetate (17alpha-acetoxy-11beta-(4N-N,N-dymethilaminophenyl)-19-norpregna--4,9-diene-3,20-dione) is the first drug that was specifically developed and licensed for use as an emergency contraceptive. It is an orally active, synthetic, selective progesterone modulator that acts by binding with high affinity to the human progesterone receptor where it has both antagonist and partial agonist effects. It is a new molecular entity and the first compound in a new pharmacological class defined by the pristal stem. Up on the superior clinical efficacy evidence, UPA has been quickly recognized as the most effective emergency contraceptive pill, and recently recommended as the first prescription choice for all women regardless of the age and timing after intercourse. This article provides literature review of UPA and its role in emergency contraception.

  15. Hydrothermally synthesized PZT film grown in highly concentrated KOH solution with large electromechanical coupling coefficient for resonator

    Science.gov (United States)

    Feng, Guo-Hua; Lee, Kuan-Yi

    2017-12-01

    This paper presents a study of lead zirconate titanate (PZT) films hydrothermally grown on a dome-shaped titanium diaphragm. Few articles in the literature address the implementation of hydrothermal PZT films on curved-diaphragm substrates for resonators. In this study, a 50-μm-thick titanium sheet is embossed using balls of designed dimensions to shape a dome-shaped cavity array. Through single-process hydrothermal synthesis, PZT films are grown on both sides of the processed titanium diaphragm with good adhesion and uniformity. The hydrothermal synthesis process involves a high concentration of potassium hydroxide solution and excess amounts of lead acetate and zirconium oxychloride octahydrate. Varied deposition times and temperatures of PZT films are investigated. The grown films are characterized by X-ray diffraction and scanning electron microscopy. The 10-μm-thick PZT dome-shaped resonators with 60- and 20-μm-thick supporting layers are implemented and further tested. Results for both resonators indicate that large electromechanical coupling coefficients and a series resonance of 95 MHz from 14 MHz can be attained. The device is connected to a complementary metal-oxide-semiconductor integrated circuit for analysis of oscillator applications. The oscillator reaches a Q value of 6300 in air. The resonator exhibits a better sensing stability when loaded with water when compared with air.

  16. The BGU/CERN solar hydrothermal reactor

    CERN Document Server

    Bertolucci, Sergio; Caspers, Fritz; Garb, Yaakov; Gross, Amit; Pauletta, Stefano

    2014-01-01

    We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (BGU) and the European Organization for Nuclear Research CERN. We describe in broad terms the several novel aspects of the device and, by extension, of the niche it occupies: in particular, enabling direct off-grid conversion of a range of organic feedstocks to sterile useable (solid, liquid) fuels, nutrients, products using only solar energy and water. We then provide a brief description of the high temperature high efficiency panels that provide process heat to the hydrothermal reactor, and review the basics of hydrothermal processes and conversion taking place in this. We conclude with a description of a simulation of the pilot system that will begin operation later this year.

  17. Hydrothermal Ni Prospectivity Analysis of Tasmania, Australia

    Science.gov (United States)

    Gonzalez-Alvarez, I.; Porwal, A.; McCuaig, T. C.; Maier, W.

    2009-04-01

    Tasmania contains the largest hydrothermal Ni deposit in Australia: Avebury (118,000 Ni metal tonnes). This Devonian deposit was discovered in 1998 in the Dundas geological region, and consists of a system of hydrothermal Ni ore bodies. They are hosted by an intensely altered and serpentinized Cambrian ultramafic suite in close proximity to major structural features. The mineralization is considered to be the result of hydrothermal scavenging and remobilization of the original nickel content of mafic/ultramafic rocks in the area, and subsequent re-deposition in favourable structural traps. This is based on the low sulphur, low Cu and Platinum element content of the mineralization. The mineralization is spatially (at the edge) and temporally related to a large granitic intrusion, the Heemskirk Granite, which is considered to be the source of the hydrothermal fluids as well as the necessary thermal gradients for the circulation of the fluids. Tasmania is largely covered by the Jurassic Ferrar continental flood basalt province in the East and constrains a number of early Cambrian ultramafic-mafic complexes in the West. The Ferrar large igneous province (LIP) extends over to Antarctica and is temporally and genetically related to the Karoo igneous province in southern Africa that comprises tholeiitic lava flows, sills, and dyke swarms. The Ferrar and Karoo igneous provinces were associated with the same thermal anomaly that was responsible for the break up of eastern Gondwana at ca 180 Ma. Despite of timeframe differences between the Avebury Ni deposits and the Ferrar LIP emplacement, similar geological settings to the Avebury could be duplicated along the Ferrar LIP. The presence of mafic/ultramafic rocks in favourable lithological packages and/or structural traps along the margins of the province indicate that this LIP could represent a possible exploration target for Ni hydrothermal deposits. Based on this background, a prospectivity analysis for hydrothermal Ni

  18. Hydrothermal processing of radioactive combustible waste

    International Nuclear Information System (INIS)

    Worl, L.A.; Buelow, S.J.; Harradine, D.; Le, L.; Padilla, D.D.; Roberts, J.H.

    1998-01-01

    Hydrothermal processing has been demonstrated for the treatment of radioactive combustible materials for the US Department of Energy. A hydrothermal processing system was designed, built and tested for operation in a plutonium glovebox. Presented here are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. Experiments show the destruction of the organic component to CO 2 and H 2 O, with 30 wt.% H 2 O 2 as an oxidant, at 540 C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provide corrosion resistance for the oxidation of chlorinated organics. The treatment of solid material is accomplished by particle size reduction and the addition of a viscosity enhancing agent to generate a homogeneous pumpable mixture

  19. Hydrothermal processing of transuranic contaminated combustible waste

    International Nuclear Information System (INIS)

    Buelow, S.J.; Worl, L.; Harradine, D.; Padilla, D.; McInroy, R.

    2001-01-01

    Experiments at Los Alamos National Laboratory have demonstrated the usefulness of hydrothermal processing for the disposal of a wide variety of transuranic contaminated combustible wastes. This paper provides an overview of the implementation and performance of hydrothermal treatment for concentrated salt solutions, explosives, propellants, organic solvents, halogenated solvents, and laboratory trash, such as paper and plastics. Reaction conditions vary from near ambient temperatures and pressure to over 1000degC and 100 MPa pressure. Studies involving both radioactive and non-radioactive waste simulants are discussed. (author)

  20. Hydrothermal Synthesis of Nanostructured Vanadium Oxides

    Science.gov (United States)

    Livage, Jacques

    2010-01-01

    A wide range of vanadium oxides have been obtained via the hydrothermal treatment of aqueous V(V) solutions. They exhibit a large variety of nanostructures ranging from molecular clusters to 1D and 2D layered compounds. Nanotubes are obtained via a self-rolling process while amazing morphologies such as nano-spheres, nano-flowers and even nano-urchins are formed via the self-assembling of nano-particles. This paper provides some correlation between the molecular structure of precursors in the solution and the nanostructure of the solid phases obtained by hydrothermal treatment. PMID:28883325

  1. Acetobacter pasteurianus metabolic change induced by initial acetic acid to adapt to acetic acid fermentation conditions.

    Science.gov (United States)

    Zheng, Yu; Zhang, Renkuan; Yin, Haisong; Bai, Xiaolei; Chang, Yangang; Xia, Menglei; Wang, Min

    2017-09-01

    Initial acetic acid can improve the ethanol oxidation rate of acetic acid bacteria for acetic acid fermentation. In this work, Acetobacter pasteurianus was cultured in ethanol-free medium, and energy production was found to increase by 150% through glucose consumption induced by initial acetic acid. However, oxidation of ethanol, instead of glucose, became the main energy production pathway when upon culturing ethanol containing medium. Proteome assay was used to analyze the metabolism change induced by initial acetic acid, which provided insight into carbon metabolic and energy regulation of A. pasteurianus to adapt to acetic acid fermentation conditions. Results were further confirmed by quantitative real-time PCR. In summary, decreased intracellular ATP as a result of initial acetic acid inhibition improved the energy metabolism to produce more energy and thus adapt to the acetic acid fermentation conditions. A. pasteurianus upregulated the expression of enzymes related to TCA and ethanol oxidation to improve the energy metabolism pathway upon the addition of initial acetic acid. However, enzymes involved in the pentose phosphate pathway, the main pathway of glucose metabolism, were downregulated to induce a change in carbon metabolism. Additionally, the enhancement of alcohol dehydrogenase expression promoted ethanol oxidation and strengthened the acetification rate, thereby producing a strong proton motive force that was necessary for energy production and cell tolerance to acetic acid.

  2. The chemistry of hydrothermal magnetite: a review

    Science.gov (United States)

    Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John

    2014-01-01

    Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks. Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of the respective magnetite. Two fundamental questions underlie these efforts — (i) How can the composition of igneous and, more importantly, hydrothermal magnetite be used to discriminate mineralized areas from barren host rocks, and (ii) how can this assist exploration geologists to target ore deposits at greater and greater distances from the main mineralization? Similar to igneous magnetite, the most important factors that govern compositional variations in hydrothermal magnetite are (A) temperature, (B) fluid composition — element availability, (C) oxygen and sulfur fugacity, (D) silicate and sulfide activity, (E) host rock buffering, (F) re-equilibration processes, and (G) intrinsic crystallographic controls such as ionic radius and charge balance. We discuss how specific formation conditions are reflected in the composition of magnetite and review studies that investigate the chemistry of hydrothermal and igneous magnetite from various mineral deposits and their host rocks. Furthermore, we discuss the redox-related alteration of magnetite (martitization and mushketovitization) and mineral inclusions in magnetite and their effect on chemical analyses. Our database includes published and previously unpublished magnetite minor and trace element data for magnetite from (1) banded iron formations (BIF) and related high-grade iron ore deposits in Western Australia, India, and Brazil, (2) Ag–Pb–Zn veins of the Coeur d'Alene district, United States, (3) porphyry Cu–(Au)–(Mo) deposits and associated (4) calcic and magnesian skarn deposits in the southwestern United

  3. complexes containing acetate and tetradentate Schiff bases

    Indian Academy of Sciences (India)

    s12039-015-0842-x. Syntheses, structures and luminescence behaviour of some zinc(II) complexes containing acetate and tetradentate Schiff bases. ASHIS KUMAR MAJI, SUBHASIS ROY, SOMNATH CHOUBEY, RAJARSHI GHOSH∗ and.

  4. Clostridium thermosaccharolyticum strain deficient in acetate production

    Energy Technology Data Exchange (ETDEWEB)

    Rothstein, D.M.

    1986-01-01

    A mutant of Clostridium thermosaccharolyticum that is blocked in acetate production was isolated after treatment with nitrosoguanidine and selection for fluoroacetate resistance. The mutant produced more ethanol than the parent strain did.

  5. Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass - the "hydrothermal pump hypothesis"

    Science.gov (United States)

    Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim

    2018-03-01

    Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis).

  6. Combined hydrothermal liquefaction and catalytic hydrothermal gasification system and process for conversion of biomass feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.

    2017-09-12

    A combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) system and process are described that convert various biomass-containing sources into separable bio-oils and aqueous effluents that contain residual organics. Bio-oils may be converted to useful bio-based fuels and other chemical feedstocks. Residual organics in HTL aqueous effluents may be gasified and converted into medium-BTU product gases and directly used for process heating or to provide energy.

  7. Hydrothermal synthesis, structure and characterization of new ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Hydrothermal; crystal structure; solid electrolyte; iron (III) pyrophosphate. 1. Introduction ... tion, structure and electrical conductivity and the higher values of ..... type cavity structure. Acknowledgements. The authors would like to express their thanks to DST,. New Delhi, for financial assistance under the projects.

  8. Phase Transformation of Hydrothermally Synthesized Nanoparticle ...

    African Journals Online (AJOL)

    NJD

    Mild hydrothermal hydrolysis of TiCl4 produces nanorods of the rutile phase of titanium dioxide in high yield, while in the presence of organic ..... Reading, MA, 1969. 39 H.P. Klug and L.E. Alexander, X-ray Diffraction Procedures for. Polycrystalline and Amorphous Materials, 2nd edn. John Wiley & Sons,. New York, 1974.

  9. Hydrothermal synthesis, structure and characterization of new ...

    Indian Academy of Sciences (India)

    Unknown

    The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability. Keywords. Hydrothermal; crystal structure; solid electrolyte; iron (III) pyrophosphate. 1. Introduction. NASICON and related compounds belong to the well known family of solid ...

  10. Treatment of urban sludge by hydrothermal carbonization.

    Science.gov (United States)

    Xu, Xiwei; Jiang, Enchen

    2017-08-01

    Urban sludge was treated by Hydrothermal carbonization (HTC). The effect of hydrothermal carbonization temperature, mixing with or without catalysts on solid products yield, heavy metal contents, turbidity and COD value was evaluated. The result showed solid products yield decreased from 92.04% to 52.65% when the temperature increased from 180 to 300°C. And the Cu, Zn, and Pb contents under exchangeable states decreased and reached discharge standard. Addition of FeCl 3 or Al(OH) 3 resulted in a significant increase in the exchangeable states of Zn, Pb, Cr, and Cd and decrease in their residual states. The turbidity and COD value of hydrothermal liquid decreased from 450° to 175°, and 13 to 6.8g/L, with increasing hydrothermal temperature. Comparison with HTC, solid productivity from low-temperature pyrolysis is higher. The exchangeable states of Cu, Zn, and Cr exceeded the limiting values. Our results show HTC can facilitate transforming urban sludge into no-pollution and energy-rich products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Hydrothermal Liquefaction of the Microalgae Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Sigaard Christensen, Per; Peng, Gaël; Vogel, Frédéric

    2014-01-01

    The microalgae Phaeodactylum tricornutum was processed by hydrothermal liquefaction in order to assess the influence of reaction temperature and reaction time on the product and elemental distribution. The experiments were carried out at different reaction times (5 and 15 min) and over a wide range...

  12. Direct hydrothermal synthesis of metal intercalated hexagonal ...

    Indian Academy of Sciences (India)

    Unknown

    Increasing reaction time, temperature or decreasing pH of the initial solution with concentrated HCl or HNO3 or change in molar ratio of the reactants did not result in a single phase. The reaction of α-MoO3 with thallium chloride under hydrothermal condition yielded a new unidentified phase. In the case of silver we ended ...

  13. Hydrothermal synthesis, crystal structure and luminescence property ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 12. Hydrothermal synthesis, crystal structure and luminescence property of a three dimensional Sm(III) coordination polymer with 2,5-pyridinedicarboxylic acid. Kranthi Kumar Gangu Anima S Dadhich Saratchandra Babu Mukkamala. Volume 127 Issue 12 ...

  14. Hydrothermal synthesis of fine oxide powders

    Indian Academy of Sciences (India)

    Unknown

    Tokyo Institute of Technology, and Teikyo University of Science and Technology, 3-7-19 Seijo, Setagaya,. Tokyo 157-0066 ... peratures from 100–10,000°C. Hydrothermal is one of the best methods to produce pure fine oxide powders. The authors ... bombs and gas intensifiers for specialized gases, A, H2,. O2, NH3, etc.

  15. Geochemistry of hydrothermal gold deposits: A review

    Directory of Open Access Journals (Sweden)

    Yongfeng Zhu

    2011-07-01

    Full Text Available Mineral assemblages formed during hydrothermal alteration reflect the geochemical composition of ore-forming fluids. Gold is mainly transported in solution as Au–Cl and Au–S complexes. The change of physicochemical conditions such as temperature, pressure, oxygen fugacity, and sulfur fugacity are effective mechanisms for gold precipitation. Gold tends to be concentrated in the vapor phase of fluids at high temperatures and pressures. Au–As and Au–Sb associations are common in gold deposit. Native antimony and/or arsenic – native gold assemblages may precipitate from hydrothermal fluids with low sulfur fugacity. Hydrothermal fluids forming epithermal gold deposits are Au-saturated in most cases, whereas fluids of Carlin-type are Au-undersaturated. Quasi-steady As-bearing pyrite extracts solid solution Au from hydrothermal fluids through absorption. The capability of As-bearing pyrite to absorb Au from under-saturated fluid is the key to the formation of large-scale Carlin-type deposits. With increasing new data, studies on the geochemistry of gold deposits can be used to trace the origin of ore-forming fluids, the source of gold, and the transporting form of Au and other ore-forming elements, such as Si, S, F, Cl, As and Ag.

  16. Hydrothermal synthesis and electrochemical properties of a ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 5. Hydrothermal synthesis and electrochemical properties of a coordination polymer based on dinuclear (Pyrazinyl tetrazolate) Copper(II) cations and βOctamolybdate Anions. SHAOBIN LI LI ZHANG HUIYUAN MA HAIJUN PANG. Regular Article Volume ...

  17. HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF A ...

    African Journals Online (AJOL)

    Preferred Customer

    HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF A BINUCLEAR. COMPLEX AND A COORDINATION POLYMER OF COPPER(II). Masoumeh Tabatabaee1*, Reza Mohamadinasab1, Kazem Ghaini1 and Hamid Reza Khavasi2. 1Department of Chemistry, Islamic Azad University, Yazd Branch, Yazd, Iran.

  18. Valorization of Furfural Residue by Hydrothermal Carbonization

    DEFF Research Database (Denmark)

    Yue, Fen; Zhang, Jia; Pedersen, Christian Marcus

    2017-01-01

    Furfural residue (FR) is a low-cost by-product generated in the furfural production from corncobs, which is mainly composed of cellulose and lignin. In this report, hydrothermal carbonization (HTC) of deashed FR was conducted at various reaction temperatures (200, 220 and 240 °C) and reaction tim...

  19. Trace elements characterization of the hydrothermally deposited ...

    African Journals Online (AJOL)

    With the exception of higher barium contents in pelites, trace element contents in the psammitic and pelitic gneisses show some similarities while in the hydrothermally altered rocks where gemstones (tanzanite and green grossular) are localized reveal that the following trace elements: Ba, Cu, Mo, Ni, Rb, Sr, U, V and Zn ...

  20. Role of hydrothermal temperature on crystallinity ...

    Indian Academy of Sciences (India)

    M MALLIGAVATHY

    2018-02-22

    Feb 22, 2018 ... vapour was better compared to other gases for the sample synthesised at 160. ◦. C. Keywords. Hydrothermal method ... obstacle against ionic exchange which slows down the breaking of surface oxide layer and thus, ... to achieve a higher degradation rate is discussed. The sensing properties of various ...

  1. Hemo-De as substitute for ethyl acetate in formalin-ethyl acetate concentration technique.

    OpenAIRE

    Neimeister, R; Logan, A L; Gerber, B; Egleton, J H; Kleger, B

    1987-01-01

    In comparative studies, Hemo-De (PMP Medical Industries, Inc., Irving, Tex.) was found to be a suitable replacement for ethyl acetate in the Formalin-ethyl acetate concentration technique. With essentially equivalent recovery rates for both procedures, the Formalin-Hemo-De concentration technique is considered to be the preferred technique because Hemo-De is less toxic and less flammable and does not present disposal problems, and its cost is approximately one-fourth that of ethyl acetate.

  2. Demand boom boosts ethyl, butyl acetate

    International Nuclear Information System (INIS)

    Coeyman, M.

    1993-01-01

    US ethyl and butyl acetate markets are being described as 'extremely tight.' One major domestic producer is 'in a sold-out position' and has 'gone on sales control' with respect to these two products. Producers say that sales of both ethyl and butyl acetate have increased during the past year, and industry observers say they expect to see an April 1 price initiative of 2 cts to 3 cts/lb, and possibly a second increase in October. While one producer suggests that this market strength could be 'a sign that the coatings industry is turning around,' most agree that reformulation is the principal driver of growth. Ethyl acetate is said to be replacing methyl ethyl ketone in many formulations, while butyl acetate and butyl acetate blends are substituting for methyl isobutyl ketone. In addition, both ethyl and butyl acetate work as substitutes for xylene and toluene in certain applications. In an effort to conform to the requirements of the Clean Air Act of 1990 and to cooperate with the Environmental Protection Agency's 33/50 voluntary emissions reduction program, coatings manufacturers are moving as quickly as possible to eliminate solvents from their products. And although solvents as a whole will eventually see a dramatic decline in consumption, the temporary beneficiaries of reformulation will be certain of the oxygenated solvents, says Jeff Back, business manager at Kline ampersand Co

  3. Hydrothermal focusing of chemical and chemiosmotic energy, supported by delivery of catalytic Fe, Ni, Mo/W, Co, S and Se, forced life to emerge.

    Science.gov (United States)

    Nitschke, Wolfgang; Russell, Michael J

    2009-11-01

    Energised by the protonmotive force and with the intervention of inorganic catalysts, at base Life reacts hydrogen from a variety of sources with atmospheric carbon dioxide. It seems inescapable that life emerged to fulfil the same role (i.e., to hydrogenate CO(2)) on the early Earth, thus outcompeting the slow geochemical reduction to methane. Life would have done so where hydrothermal hydrogen interfaced a carbonic ocean through inorganic precipitate membranes. Thus we argue that the first carbon-fixing reaction was the molybdenum-dependent, proton-translocating formate hydrogenlyase system described by Andrews et al. (Microbiology 143:3633-3647, 1997), but driven in reverse. Alkaline on the inside and acidic and carbonic on the outside - a submarine chambered hydrothermal mound built above an alkaline hydrothermal spring of long duration - offered just the conditions for such a reverse reaction imposed by the ambient protonmotive force. Assisted by the same inorganic catalysts and potential energy stores that were to evolve into the active centres of enzymes supplied variously from ocean or hydrothermal system, the formate reaction enabled the rest of the acetyl coenzyme-A pathway to be followed exergonically, first to acetate, then separately to methane. Thus the two prokaryotic domains both emerged within the hydrothermal mound-the acetogens were the forerunners of the Bacteria and the methanogens were the forerunners of the Archaea.

  4. Organic sulfur metabolisms in hydrothermal environments.

    Science.gov (United States)

    Rogers, Karyn L; Schulte, Mitchell D

    2012-07-01

    Sulfur is central to the metabolisms of many organisms that inhabit extreme environments. While biotic and abiotic cycling of organic sulfur compounds has been well documented in low-temperature anaerobic environments, cycling of organic sulfur in hydrothermal environments has received less attention. Recently published thermodynamic data have been used to estimate aqueous alkyl thiol and sulfide activities in deep-sea hydrothermal systems. Here we use geochemical mixing models to predict fluid compositions that result from mixing end-member hydrothermal fluid from the East Pacific Rise with bottom seawater. These fluid compositions are combined with estimates of methanethiol and dimethylsulfide activities to evaluate energy yields for potential organic sulfur-based metabolisms under hydrothermal conditions. Aerobic respiration has the highest energy yields (over -240 kJ/mol e⁻) at lower temperature; however, oxygen is unlikely to persist at high temperatures, restricting aerobic respiration to mesophilic communities. Nitrite reduction to N₂ has the highest energy yields at higher temperatures (greater than ∼40 °C). Nitrate and nitrite reduction to ammonium also yield significant energy (up to -70 kJ/mol e⁻). Much lower, but still feasible energy yields are calculated for sulfate reduction, disproportionation, and reduction with H₂. Organic compound family and the activity of methanethiol and dimethylsulfide were less important than metabolic strategy in determining overall energy yields. All metabolic strategies considered were exergonic within some portion of the mixing regime suggesting that organic sulfur-based metabolisms may be prevalent within deep-sea hydrothermal vent microbial communities. © 2012 Blackwell Publishing Ltd.

  5. Voltammetric Investigation Of Hydrothermal Iron Speciation

    Directory of Open Access Journals (Sweden)

    Charlotte eKleint

    2016-05-01

    Full Text Available Hydrothermal vent fluids are highly enriched in iron (Fe compared to ambient seawater, and organic ligands may play a role in facilitating the transport of some hydrothermal Fe into the open ocean. This is important since Fe is a limiting micronutrient for primary production in large parts of the world`s surface ocean. We have investigated the concentration and speciation of Fe in several vent fluid and plume samples from the Nifonea vent field, Coriolis Troughs, New Hebrides Island Arc, South Pacific Ocean using competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE - AdCSV with salicylaldoxime (SA as the artificial ligand. Our results for total dissolved Fe (dFe in the buoyant hydrothermal plume samples showed concentrations up to 3.86 µM dFe with only a small fraction between 1.1% and 11.8% being chemically labile. Iron binding ligand concentrations ([L] were found in µM level with strong conditional stability constants up to log K[L],Fe3+ of 22.9. Within the non-buoyant hydrothermal plume above the Nifonea vent field, up to 84.7% of the available Fe is chemically labile and [L] concentrations up to 97 nM were measured. [L] was consistently in excess of Felab, indicating that all available Fe is being complexed, which in combination with high Felab values in the non-buoyant plume, signifies that a high fraction of hydrothermal dFe is potentially being transported away from the plume into the surrounding waters, contributing to the global oceanic Fe budget.

  6. Hydrothermal systems in small ocean planets.

    Science.gov (United States)

    Vance, Steve; Harnmeijer, Jelte; Kimura, Jun; Hussmann, Hauke; Demartin, Brian; Brown, J Michael

    2007-12-01

    We examine means for driving hydrothermal activity in extraterrestrial oceans on planets and satellites of less than one Earth mass, with implications for sustaining a low level of biological activity over geological timescales. Assuming ocean planets have olivine-dominated lithospheres, a model for cooling-induced thermal cracking shows how variation in planet size and internal thermal energy may drive variation in the dominant type of hydrothermal system-for example, high or low temperature system or chemically driven system. As radiogenic heating diminishes over time, progressive exposure of new rock continues to the current epoch. Where fluid-rock interactions propagate slowly into a deep brittle layer, thermal energy from serpentinization may be the primary cause of hydrothermal activity in small ocean planets. We show that the time-varying hydrostatic head of a tidally forced ice shell may drive hydrothermal fluid flow through the seafloor, which can generate moderate but potentially important heat through viscous interaction with the matrix of porous seafloor rock. Considering all presently known potential ocean planets-Mars, a number of icy satellites, Pluto, and other trans-neptunian objects-and applying Earth-like material properties and cooling rates, we find depths of circulation are more than an order of magnitude greater than in Earth. In Europa and Enceladus, tidal flexing may drive hydrothermal circulation and, in Europa, may generate heat on the same order as present-day radiogenic heat flux at Earth's surface. In all objects, progressive serpentinization generates heat on a globally averaged basis at a fraction of a percent of present-day radiogenic heating and hydrogen is produced at rates between 10(9) and 10(10) molecules cm(2) s(1).

  7. 21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl alcohol containing ethyl acetate. 584.200... Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets... having had added the equivalent of 4.25 gallons of 100 percent ethyl acetate. It is used in accordance...

  8. Solution (31)P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U24Pp12} Nanocluster, [(UO2)24(O2)24(P2O7)12](48-), and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction.

    Science.gov (United States)

    Dembowski, Mateusz; Olds, Travis A; Pellegrini, Kristi L; Hoffmann, Christina; Wang, Xiaoping; Hickam, Sarah; He, Junhong; Oliver, Allen G; Burns, Peter C

    2016-07-13

    The first neutron diffraction study of a single crystal containing uranyl peroxide nanoclusters is reported for pyrophosphate-functionalized Na44K6[(UO2)24(O2)24(P2O7)12][IO3]2·140H2O (1). Relative to earlier X-ray studies, neutron diffraction provides superior information concerning the positions of H atoms and lighter counterions. Hydrogen positions have been assigned and reveal an extensive network of H-bonds; notably, most O atoms present in the anionic cluster accept H-bonds from surrounding H2O molecules, and none of the surface-bound O atoms are protonated. The D4h symmetry of the cage is consistent with the presence of six encapsulated K cations, which appear to stabilize the lower symmetry variant of this cluster. (31)P NMR measurements demonstrate retention of this symmetry in solution, while in situ (31)P NMR studies suggest an acid-catalyzed mechanism for the assembly of 1 across a wide range of pH values.

  9. Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.

    Science.gov (United States)

    Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

    2015-05-01

    In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid.

  10. Genera and species in acetic acid bacteria.

    Science.gov (United States)

    Yamada, Yuzo; Yukphan, Pattaraporn

    2008-06-30

    Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically.

  11. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A., E-mail: ivan_melendez380@hotmail.com [Centro de Investigacion en Quimica Aplicada, Bldv. Enrique Reyna Hermosillo No. 140, Saltillo 25294, Coahuila (Mexico)

    2013-08-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na{sub 2}SiO{sub 3}) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO{sub 2} molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO{sub 2} molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  12. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    International Nuclear Information System (INIS)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A.

    2013-01-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na 2 SiO 3 ) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO 2 molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO 2 molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  13. Hydrothermal syntheses and crystal structure of NH

    International Nuclear Information System (INIS)

    Kang, Z. J.; Wang, Y. X.; You, F. T.; Lin, J. H.

    2001-01-01

    Ammonium rare earth fluorides NH(sub 4)Ln(sub 3)F(sub 10) (Ln=Dy, Ho, Y, Er, Tm) were synthesized by a hydrothermal method. Two polymorphs, of the hexagonal(beta)-KYb(sub 3)F(sub 10) and the cubic(gamma)-KYb(sub 3)F(sub 10) structure types, were formed under hydrothermal conditions for most of the rare earth fluorides except NH(sub 4)Dy(sub 3)F(sub 10), for which only the cubic -phase was obtained. The crystal structures of MLn(sub 3)F(sub 10) (M=alkaline metal, NH(sup+4) and Ln=rare earth) show a strong correlation to the ratio of ionic radii (R(sub M)/R(sub Ln)), which has been expressed in a structure phase diagram of the ionic radii of univalent and rare earth cations

  14. Silicon nanochains preparation with hydrothermal synthesis

    International Nuclear Information System (INIS)

    Chen, Y.W.; Tang, Y.H.; Pei, L.Z.; Guo, C.; Lin, L.W.

    2007-01-01

    Silicon nanochains over 1 μm in length and 50-100 nm in diameter have been synthesized by hydrothermal synthesis with silicon powders as start materials and de-ionized water as reaction medium, the growth condition was controlled at 470 deg. C and 9.7 MPa in a sealed reaction kettle. The morphology and microstructure of the production were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED); the results revealed that the silicon nanochains have diamond structure. Energy dispersive X-ray spectrum (EDS) was used to analyze the composition of the final production and the possible growth mechanism of silicon nanochain under supercritical hydrothermal condition was proposed

  15. Hydrothermal scheduling using chaotic hybrid differential evolution

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Xiaohui [School of Hydropower and Information Engineering, Huazhong University of Science and Technology, 430074 Wuhan (China)], E-mail: yxh71@163.com; Cao Bo; Yang Bo [Central China Grid Company Limited, 430077 Wuhan (China); Yuan Yanbin [School of Resource and Environmental Engineering, Wuhan University of Technology, 430070 Wuhan (China)

    2008-12-15

    This paper proposes a chaotic hybrid differential evolution algorithm to solve short-term hydrothermal system generation scheduling problem. In the proposed method, chaos theory is applied to obtain self-adaptive parameter settings in differential evolution (DE). In order to handle constraints effectively, feasibility-based selection comparison techniques and heuristic rules embedded into DE are devised to guide the process toward the feasible region of the search space. A test hydrothermal system is used to verify the feasibility and effectiveness of the proposed method. Results from the proposed method are compared with those obtained by augmented Lagrange and two-phase neural network methods in terms of solution quality. It is shown that the proposed method is able to obtain higher quality solutions.

  16. Whole Algae Hydrothermal Liquefaction Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, Mary J.; Davis, Ryan; Jones, Susanne B.; Zhu, Yunhua

    2013-03-31

    In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to hydrocarbon fuels to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This pathway case investigates the feasibility of using whole wet microalgae as a feedstock for conversion via hydrothermal liquefaction. Technical barriers and key research needs have been assessed in order for the hydrothermal liquefaction of microalgae to be competitive with petroleum-derived gasoline, diesel and jet range blendstocks.

  17. Physical balances in subseafloor hydrothermal convection cells

    Science.gov (United States)

    Jupp, Tim E.; Schultz, Adam

    2004-05-01

    We use a simplified model of convection in a porous medium to investigate the balances of mass and energy within a subseafloor hydrothermal convection cell. These balances control the steady state structure of the system and allow scalings for the height, permeability, and residence time of the "reaction zone" at the base of the cell to be calculated. The scalings are presented as functions of (1) the temperature TD of the heat source driving the convection and (2) the total power output ΦU. The model is then used to illustrate how the nonlinear thermodynamic properties of water may impose the observed upper limit of ˜400°C on vent temperatures. The properties of water at hydrothermal conditions are contrasted with those of a hypothetical "Boussinesq fluid" for which temperature variations in fluid properties are either linearized or ignored. At hydrothermal pressures, water transports a maximum amount of energy by buoyancy-driven advection at ˜400°C. This maximum is a consequence of the nonlinear thermodynamic properties of water and does not arise for a simple Boussinesq fluid. Inspired by the "Malkus hypothesis" and by recent work on dissipative systems, we speculate that convection cells in porous media attain a steady state in which the upwelling temperature TU maximizes the total power output of the cell. If true, this principle would explain our observation (in previous numerical simulations) that water in hydrothermal convection cells upwells at TU ˜ 400°C when driven by a heat source above ˜500°C.

  18. Numerical modeling of oceanic crustal hydrothermal systems

    Science.gov (United States)

    Latychev, Konstantin

    The oceanic crust is a complex rock-mineral formation which extends up to several kilometers below the sea floor and covers laterally about two thirds of the planet. Hydrothermal circulation within the crust is driven by magmatic sources and carried by the fluid residing in pores and cracks. Hydrothermal advection transfers about one quarter of the Earth's total heat power from the interior. Marine sediments are believed to be the largest repositories of solid ice-like methane clathrate hydrates. The compliance technique is an important tool for assessment of this resource. It makes use of the oceanic surface gravity waves to induce pressure variations on the sea floor and measure the corresponding vertical deformation. This thesis deals with the convective heat and mass transfer within the oceanic crust, as a fractured porous medium, and the elastic, quasi-static response of hydrated marine sediments to gravity wave loading. Both generic and site-specific applications are considered. Most applications are tackled numerically in three spatial dimensions. The major results are as follows. Fractures can trigger and maintain hydrothermal circulation. The permeability-thickness product in the direction of flow is an adequate parameter to represent the fracture if convection is not vigorous. A new temperature homogenization mechanism for the off-axial convection is proposed which is due to quasi-lateral circulation within a permeable zone between sediment cover and basalt. It explains both the observed correlation between surface heat flux and sediment thickness, as well as regular heat flux variations when no buried topography is present. A hydrothermal model for the CoAxial Segment of the Juan de Fuca Ridge predicts ridge-parallel convection with the low-temperature vents spaced 1 km apart. The compliance approach is feasible for a non-layered medium. The average compliance response depends on the bulk hydrate content, but not on a particular connectivity pattern

  19. Hydrothermal pretreatments of macroalgal biomass for biorefineries

    DEFF Research Database (Denmark)

    Ruiz, Héctor A.; Rodríguez-Jasso, Rosa M.; Aguedo, Mario

    2015-01-01

    ecently, macroalgal biomass is gaining wide attention as an alternative in the production of biofuels (as bioetanol and biogas) and compounds with high added value with specific properties (antioxidants, anticoagulants, anti–inflammatories) for applications in food, medical and energy industries...... in accordance with the integrated biorefineries. Furthermore, biorefinery concept requires processes that allow efficient utilization of all components of the biomass. The pretreatment step in a biorefinery is often based on hydrothermal principles of high temperatures in aqueous solution. Therefore...

  20. Rapid hydrothermal flow synthesis and characterisation of carbonate- and silicate-substituted calcium phosphates

    Science.gov (United States)

    Knowles, Jonathan C; Rehman, Ihtesham; Darr, Jawwad A

    2013-01-01

    A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising phase pure carbonated hydroxyapatite (CO3-HA) with ≈5 wt% substituted carbonate content (sample 7.5CO3-HA) and it was found that a further increase in urea concentration in solution resulted in biphasic mixtures of carbonate-substituted hydroxyapatite and calcium carbonate. Transmission electron microscopy images revealed that the particle size of hydroxyapatite decreased with increasing urea concentration. Energy-dispersive X-ray spectroscopy result revealed a calcium deficient apatite with Ca:P molar ratio of 1.45 (±0.04) in sample 7.5CO3-HA. For silicate-substituted hydroxyapatite (SiO4-HA) silicon acetate was used as a silicate ion source. It was observed that a substitution threshold of ∼1.1 wt% exists for synthesis of SiO4-HA in the continuous hydrothermal flow synthesis system, which could be due to the decreasing yields with progressive increase in silicon acetate concentration. All the as-precipitated powders (without any additional heat treatments) were analysed using techniques including Transmission electron microscopy, X-ray powder diffraction, Differential scanning calorimetry, Thermogravimetric analysis, Raman spectroscopy and Fourier transform infrared spectroscopy. PMID:22983020

  1. Hydrothermal treatment of coprecipitated YSZ powders

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo; Yoshito, Walter Kenji; Ussui, Valter; Lazar, Dolores Ribeiro Ricci

    2009-01-01

    Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermally treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, uniaxially pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N 2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density. (author)

  2. Acetic acid mediated interactions between alumina surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kimiyasu, E-mail: sato.kimiyasu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Anagahora 2266-98, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Y Latin-Small-Letter-Dotless-I lmaz, Hueseyin [National Institute of Advanced Industrial Science and Technology (AIST), Anagahora 2266-98, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Gebze Institute of Technology, Materials Science and Engineering Department, 41400, Gebze-Kocaeli (Turkey); Ijuin, Atsuko; Hotta, Yuji; Watari, Koji [National Institute of Advanced Industrial Science and Technology (AIST), Anagahora 2266-98, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan)

    2012-02-01

    Low-molecular-weight organic acids have been known to modify colloidal stability of alumina-based suspensions. We investigated interaction forces between alumina surfaces mediated by acetic acid which is one of the simplest organic acids. Forces between alumina surfaces were measured using the colloid-probe method of atomic force microscope (AFM). Repulsive forces attributed to steric repulsion due to adsorbed molecules and electrostatic repulsion dominated the interaction. Results of rheological characterization of the alumina slurry containing acetic acid supported the finding.

  3. Characterization of biochars and dissolved organic matter phases obtained upon hydrothermal carbonization of Elodea nuttallii.

    Science.gov (United States)

    Poerschmann, J; Weiner, B; Wedwitschka, H; Zehnsdorf, A; Koehler, R; Kopinke, F-D

    2015-01-01

    The invasive aquatic plant Elodea nuttallii was subjected to hydrothermal carbonization at 200 °C and 240 °C to produce biochar. About 58% w/w of the organic carbon of the pristine plant was translocated into the solid biochar irrespectively of the operating temperature. The process water rich in dissolved organic matter proved a good substrate for biogas production. The E. nuttallii plants showed a high capability of incorporating metals into the biomass. This large inorganic fraction which was mainly transferred into the biochar (except sodium and potassium) may hamper the prospective application of biochar as soil amendment. The high ash content in biochar (∼ 40% w/w) along with its relatively low content of organic carbon (∼ 36% w/w) is associated with low higher heating values. Fatty acids were completely hydrolyzed from lipids due to hydrothermal treatment. Low molecular-weight carboxylic acids (acetic and lactic acid), phenols and phenolic acids turned out major organic breakdown products. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Hydrothermal growth of upright-standing ZnO sheet microcrystals

    International Nuclear Information System (INIS)

    Shi, Ruixia; Yang, Ping; Dong, Xiaobin; Jia, Changchao; Li, Jia

    2014-01-01

    Highlights: • Upright-standing ZnO sheet microcrystals were hydrothermally fabricated. • The ZnO sheets were prepared with sodium oxalate at 70 °C without any surfactant. • The preferable adsorption of oxalate anions causes the formation of ZnO sheet. • The continuous growth in six directions leads to the formation of hexagonal sheets. - Abstract: Large-scale upright-standing ZnO sheet microcrystals were fabricated on Zn substrate using sodium oxalate as structure-directing agent by a hydrothermal method at low temperature (70 °C) without any surfactant. The sheets are about 3–5 μm in dimension and 100–300 nm in thickness. The strong and narrow diffraction peaks of ZnO indicate that the sample has a good crystallinity and size. The morphology of sheet-like ZnO varied with the concentrations of sodium oxalate and reaction time. The sheet-like ZnO would transform into rod-like ones when sodium oxalate was substituted by equivalent sodium acetate. The formation of sheet-like ZnO is attributed to the preferable adsorption of oxalate anions on (0 0 0 1) face of ZnO, which inhibits the intrinsic growth of ZnO. Additionally, the continuous growth in six (0 1 −1 0) directions that have the lowest surface energy leads to the formation of hexagonal sheets

  5. Temporal changes in fluid chemistry and energy profiles in the vulcano island hydrothermal system.

    Science.gov (United States)

    Rogers, Karyn L; Amend, Jan P; Gurrieri, Sergio

    2007-12-01

    In June 2003, the geochemical composition of geothermal fluids was determined at 9 sites in the Vulcano hydrothermal system, including sediment seeps, geothermal wells, and submarine vents. Compositional data were combined with standard state reaction properties to determine the overall Gibbs free energy (DeltaG(r) ) for 120 potential lithotrophic and heterotrophic reactions. Lithotrophic reactions in the H-O-N-S-C-Fe system were considered, and exergonic reactions yielded up to 120 kJ per mole of electrons transferred. The potential for heterotrophy was characterized by energy yields from the complete oxidation of 6 carboxylic acids- formic, acetic, propanoic, lactic, pyruvic, and succinic-with the following redox pairs: O(2)/H(2)O, SO(4) (2)/H(2)S, NO(3) ()/NH(4) (+), S(0)/H(2)S, and Fe(3)O(4)/Fe(2+). Heterotrophic reactions yielded 6-111 kJ/mol e(). Energy yields from both lithotrophic and heterotrophic reactions were highly dependent on the terminal electron acceptor (TEA); reactions with O(2) yielded the most energy, followed by those with NO(3) (), Fe(III), SO(4) (2), and S(0). When only reactions with complete TEA reduction were included, the exergonic lithotrophic reactions followed a similar electron tower. Spatial variability in DeltaG(r) was significant for iron redox reactions, owing largely to the wide range in Fe(2+) and H(+) concentrations. Energy yields were compared to those obtained for samples collected in June 2001. The temporal variations in geochemical composition and energy yields observed in the Vulcano hydrothermal system between 2001 and 2003 were moderate. The largest differences in DeltaG(r) over the 2 years were from iron redox reactions, due to temporal changes in the Fe(2+) and H(+) concentrations. The observed variations in fluid composition across the Vulcano hydrothermal system have the potential to influence not only microbial diversity but also the metabolic strategies of the resident microbial communities.

  6. Silver nanoparticles in combination with acetic acid and zinc oxide quantum dots for antibacterial activities improvement—A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Sedira, Sofiane, E-mail: sofianebilel@gmail.com [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Ayachi, Ahmed Abdelhakim, E-mail: ayachi-med@hotmail.fr [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Lakehal, Sihem, E-mail: lakehal.lakehal@gmail.com [Ceramic Laboratory, University of Constantine1, Constantine (Algeria); Fateh, Merouane, E-mail: merouane.fateh@gmail.com [Microbiological Laboratory Engineering and Application, University of Constantine1, Constantine (Algeria); Achour, Slimane, E-mail: achourslimane11@yahoo.fr [Ceramic Laboratory, University of Constantine1, Constantine (Algeria)

    2014-08-30

    Graphical abstract: - Highlights: • Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method. • Ag NPs exert their bactericidal effect mainly by Ag{sup +} ions. • CH{sub 3}COOH addition to Ag NPs improves bactericidal effect more than ZnO Qds addition. • E. coli and P. aeruginosa are more sensitive to NPs than K. pneumonia and S. aureus. - Abstract: Due to their remarkable antibacterial/antivirus properties, silver nanoparticles (Ag NPs) and zinc oxide quantum dots (ZnO Qds) have been widely used in the antimicrobial field. The mechanism of action of Ag NPs on bacteria was recently studied and it has been proven that Ag NPs exerts their antibacterial activities mainly by the released Ag{sup +}. In this work, Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method, respectively. It was demonstrated that Ag NPs can be oxidized easily in aqueous solution and the addition of acetic acid can increase the Ag{sup +} release which improves the antibacterial activity of Ag NPs. A comparative study between bactericidal effect of Ag NPs/acetic acid and Ag NPs/ZnO Qds on Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus was undertaken using agar diffusion method. The obtained colloids were characterized using UV–vis spectroscopy, Raman spectrometry, X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM)

  7. A case of anaphylactoid reaction to acetate in acetate-containing bicarbonate dialysate.

    Science.gov (United States)

    Misaki, Taro; Suzuki, Yumiko; Naito, Yoshitaka; Shiooka, Tempei; Isozaki, Taisuke

    2015-05-01

    A 35-year-old man with end-stage kidney disease due to chronic glomerulonephritis was admitted to our hospital to start maintenance hemodialysis (HD). One hour after starting the first session of HD, he experienced general pruritus, urticaria, and dyspnea. Signs and symptoms were resolved by discontinuing HD and administrating an antihistamine drug; HD-associated anaphylactoid reactions were therefore suspected. Over the next few HD sessions, we changed the dialysis membrane, anticoagulant, HD circuit and needle, in that order, but general pruritus and urticaria again appeared within 3 h after starting each session of HD. Finally, when we changed the dialysate from acetate-containing bicarbonate dialysate to acetate-free bicarbonate dialysate, urticaria was clearly less than that seen in previous HD sessions, and subsided after discontinuation of HD. Subsequently, 20 mg of oral prednisolone (PSL) was administered 1 h before starting HD, and the patient did not experience general pruritus, urticaria, or dyspnea after starting the session. When administered acetate-containing bicarbonate dialysate after oral PSL pretreatment, the patient again experienced general pruritus, urticaria and dyspnea. Few reports have been published on the occurrence of anaphylactoid reactions during HD using acetate dialysate. We report a rare case of anaphylactoid reactions with acetate in acetate-containing bicarbonate dialysate that were reduced with the use of acetate-free bicarbonate dialysate and oral PSL pretreatment.

  8. Direct catalytic hydrothermal liquefaction of spirulina to biofuels with hydrogen

    Science.gov (United States)

    Zeng, Qin; Liao, Hansheng; Zhou, Shiqin; Li, Qiuping; Wang, Lu; Yu, Zhihao; Jing, Li

    2018-01-01

    We report herein on acquiring biofuels from direct catalytic hydrothermal liquefaction of spirulina. The component of bio-oil from direct catalytic hydrothermal liquefaction was similar to that from two independent processes (including liquefaction and upgrading of biocrude). However, one step process has higher carbon recovery, due to the less loss of carbons. It was demonstrated that the yield and HHV of bio-oil from direct catalytic algae with hydrothermal condition is higher than that from two independent processes.

  9. Hydrothermal plumes over the Carlsberg Ridge, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ray, D.; KameshRaju, K.A.; Baker, E.T.; Rao, A.S.; Mudholkar, A.V.; Lupton, J.E.; SuryaPrakash, L.; Gawas, R.B.; VijayaKumar, T.

    year later [Ray et al., 2008] found evidence of a chronic hydrothermal plume. Neither study was able to provide any information about the location of seafloor vent sources. Other than these slim results, no other hydrothermal evidence has been.... The newly discovered submarine plumes have a maximum thickness of ~200 m and maximum rise height of about 400 m from seafloor, resembling a typical chronic hydrothermal plume rather than the apparent event plume discovered on the Carlsberg Ridge by Murton...

  10. Vinyl acetate polymerization by ionizing radiation

    International Nuclear Information System (INIS)

    Mesquita, Andrea Cercan

    2002-01-01

    The aim of this work is the synthesis and characterization of the poly(vinyl acetate) using the ionizing radiation. Six polymerizations of vinyl acetate were carried out using three techniques of polymerization: in bulk, emulsion and solution. In the technique of solution polymerization were used two solvents, the alcohol ethyl and the methylethylketone, in two proportions 1:0.5 and 1:1 related to the monomer. The solutions were irradiated with gamma rays from a 60 Co source, with dose rate between 5.25 kGy/h and 6.26 kGy/h. The polymers obtained were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The glass transition temperature (Tg) was investigated by Differential Scanning Calorimeter (DSC). The molecular weight was analyzed by the technique of Gel Permeation Chromatography (GPC). Tests of density, hardness and Vicat softening temperature were carried out. The infrared spectroscopy and others results confirmed that the polymers obtained by polymerization of vinyl acetate in bulk, emulsion and solution, using ionizing radiation, really correspond at poly(vinyl acetate). (author)

  11. Cellulose acetate electrospun nanofibrous membrane: fabrication ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Bulletin of Materials Science; Volume 39; Issue 2. Cellulose acetate electrospun nanofibrous membrane: fabrication, characterization, drug loading and antibacterial properties. NAZNIN SULTANA ... The CA nanofibrous membrane was non-toxic to human skin fibroblast cells. Thus the CA ...

  12. 21 CFR 73.2396 - Lead acetate.

    Science.gov (United States)

    2010-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR... mustaches, eyelashes, eyebrows, or hair on parts of the body other than the scalp. (d) Labeling requirements... displayed thereon: CAUTION: Contains lead acetate. For external use only. Keep this product out of children...

  13. Cuprous oxide thin films grown by hydrothermal electrochemical deposition technique

    International Nuclear Information System (INIS)

    Majumder, M.; Biswas, I.; Pujaru, S.; Chakraborty, A.K.

    2015-01-01

    Semiconducting cuprous oxide films were grown by a hydrothermal electro-deposition technique on metal (Cu) and glass (ITO) substrates between 60 °C and 100 °C. X-ray diffraction studies reveal the formation of cubic cuprous oxide films in different preferred orientations depending upon the deposition technique used. Film growth, uniformity, grain size, optical band gap and photoelectrochemical response were found to improve in the hydrothermal electrochemical deposition technique. - Highlights: • Cu 2 O thin films were grown on Cu and glass substrates. • Conventional and hydrothermal electrochemical deposition techniques were used. • Hydrothermal electrochemical growth showed improved morphology, thickness and optical band gap

  14. Inhibitors degradation and microbial response during continuous anaerobic conversion of hydrothermal liquefaction wastewater.

    Science.gov (United States)

    Si, Buchun; Li, Jiaming; Zhu, Zhangbing; Shen, Mengmeng; Lu, Jianwen; Duan, Na; Zhang, Yuanhui; Liao, Qiang; Huang, Yun; Liu, Zhidan

    2018-07-15

    One critical challenge of hydrothermal liquefaction (HTL) is its complex aqueous product, which has a high concentration of organic pollutants (up to 100gCOD/L) and diverse fermentation inhibitors, such as furfural, phenolics and N-heterocyclic compounds. Here we report continuous anaerobic digestion of HTL wastewater via an up-flow anaerobic sludge bed reactor (UASB) and packed bed reactor (PBR). Specifically, we investigated the transformation of fermentation inhibitors and microbial response. GC-MS identified the complete degradation of furfural and 5-hydroxymethylfurfural (5-HMF), and partial degradation (54.0-74.6%) of organic nitrogen and phenolic compounds, including 3-hydroxypyridine, phenol and 4-ethyl-phenol. Illumina MiSeq sequencing revealed that the bacteria families related to detoxification increased in response to the HTL aqueous phase. In addition, the increase of acetate-oxidizing bacteria in UASB and acetogens in PBR showed a strengthened acetogenesis. As for the archaeal communities, an increase in hydrogenotrophic methanogens was observed. Based on GC-MS/HPLC and microbial analysis, we speculate that dominant fermentation inhibitors were transformed into intermediates (Acetyl-CoA and acetate), further contributing to biomethane formation. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Hydrothermal germination models: Improving experimental efficiency by limiting data collection to the relevant hydrothermal range

    Science.gov (United States)

    Hydrothermal models used to predict germination response in the field are usually parameterized with data from laboratory experiments that examine the full range of germination response to temperature and water potential. Inclusion of low water potential and high and low-temperature treatments, how...

  16. Hydrothermal synthesis of hexagonal magnesium hydroxide nanoflakes

    International Nuclear Information System (INIS)

    Wang, Qiang; Li, Chunhong; Guo, Ming; Sun, Lingna; Hu, Changwen

    2014-01-01

    Graphical abstract: Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method in the presence of PEG-20,000. Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake yielded different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. - Highlights: • Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method. • PEG-20,000 plays an important role in the formation of hexagonal nanostructure. • Mg(OH) 2 nanoflakes show different crystalline structures at different positions. • The probable formation mechanism of hexagonal Mg(OH) 2 nanoflakes was reported. - Abstract: Hexagonal magnesium hydroxide (Mg(OH) 2 ) nanoflakes were successfully synthesized via hydrothermal method in the presence of the surfactant polyethylene glycol 20,000 (PEG-20,000). Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The composition, morphologies and structure of the Mg(OH) 2 nanoflakes were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake show different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. Brunauer–Emmett–Teller (BET) analysis were performed to investigate the porous structure and surface area of the as-obtained nanoflakes

  17. Oestrus induction using fluorogestone acetate sponges and equine ...

    African Journals Online (AJOL)

    fluorogestone acetate sponge) alone or in combination with equine chorionic gonadotrophin (eCG) on oestrus response in Red Sokoto (RS) goats. One hundred RS does were treated with 30 mg fluorogestone acetate (FGA) sponges for 14 ...

  18. 21 CFR 182.8892 - α-Tocopherol acetate.

    Science.gov (United States)

    2010-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8892 α-Tocopherol acetate. (a) Product. α-Tocopherol acetate. (b) Conditions of use. This substance is generally...

  19. Sonar observation of diffuse hydrothermal flows

    Science.gov (United States)

    Jackson, D. R.; Ivakin, A. N.; Xu, G.; Bemis, K. G.

    2017-05-01

    Previous studies have used multibeam sonar data to map diffuse hydrothermal flows by exploiting the decorrelation of successive seafloor echoes caused by temperature fluctuations. The present work extends this approach to quantify temperature fluctuations integrated along the sonar line of sight. The method is illustrated using data from the Cabled Observatory Vent Imaging Sonar deployed at the Grotto Vent complex on the Endeavour Segment of the Juan de Fuca Ridge. Inversion results are presented in the form of the structure function for integrated temperature fluctuations. A three-parameter fit to the structure function provides time series encapsulating statistics of these fluctuations.

  20. Hydrothermal Liquefaction Treatment Preliminary Hazard Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, Peter P.; Wagner, Katie A.

    2015-08-31

    A preliminary hazard assessment was completed during February 2015 to evaluate the conceptual design of the modular hydrothermal liquefaction treatment system. The hazard assessment was performed in 2 stages. An initial assessment utilizing Hazard Identification and Preliminary Hazards Analysis (PHA) techniques identified areas with significant or unique hazards (process safety-related hazards) that fall outside of the normal operating envelope of PNNL and warranted additional analysis. The subsequent assessment was based on a qualitative What-If analysis. This analysis was augmented, as necessary, by additional quantitative analysis for scenarios involving a release of hazardous material or energy with the potential for affecting the public.

  1. Vertical Cable Seismic Survey for Hydrothermal Deposit

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2012-04-01

    The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (Vertical Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the vertical cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have, however, also confirmed that the uncertainty in the locations of the source and of the hydrophones could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures a accurate positioning and a deployment techniques

  2. Hydrothermal synthesis of bismuth germanium oxide

    Science.gov (United States)

    Boyle, Timothy J.

    2016-12-13

    A method for the hydrothermal synthesis of bismuth germanium oxide comprises dissolving a bismuth precursor (e.g., bismuth nitrate pentahydrate) and a germanium precursor (e.g., germanium dioxide) in water and heating the aqueous solution to an elevated reaction temperature for a length of time sufficient to produce the eulytite phase of bismuth germanium oxide (E-BGO) with high yield. The E-BGO produced can be used as a scintillator material. For example, the air stability and radioluminescence response suggest that the E-BGO can be employed for medical applications.

  3. Expression of acetate permease-like (apl) genes in subsurface communities of Geobacter species under fluctuating acetate concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Elifantz, H.; N' Guessan, L.A.; Mouser, P.J.; Williams, K H.; Wilkins, M J.; Risso, C.; Holmes, D.E.; Long, P.E.; Lovley, D.R.

    2010-03-01

    The addition of acetate to uranium-contaminated aquifers in order to stimulate the growth and activity of Geobacter species that reduce uranium is a promising in situ bioremediation option. Optimizing this bioremediation strategy requires that sufficient acetate be added to promote Geobacter species growth. We hypothesized that under acetate-limiting conditions, subsurface Geobacter species would increase the expression of either putative acetate symporters genes (aplI and aplII). Acetate was added to a uranium-contaminated aquifer (Rifle, CO) in two continuous amendments separated by 5 days of groundwater flush to create changing acetate concentrations. While the expression of aplI in monitoring well D04 (high acetate) weakly correlated with the acetate concentration over time, the transcript levels for this gene were relatively constant in well D08 (low acetate). At the lowest acetate concentrations during the groundwater flush, the transcript levels of aplII were the highest. The expression of aplII decreased 2-10-fold upon acetate reintroduction. However, the overall instability of acetate concentrations throughout the experiment could not support a robust conclusion regarding the role of apl genes in response to acetate limitation under field conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

  4. Sulfur Metabolism of Hydrogenovibrio thermophilus Strain S5 and Its Adaptations to Deep-Sea Hydrothermal Vent Environment

    Directory of Open Access Journals (Sweden)

    Lijing Jiang

    2017-12-01

    Full Text Available Hydrogenovibrio bacteria are ubiquitous in global deep-sea hydrothermal vents. However, their adaptations enabling survival in these harsh environments are not well understood. In this study, we characterized the physiology and metabolic mechanisms of Hydrogenovibrio thermophilus strain S5, which was first isolated from an active hydrothermal vent chimney on the Southwest Indian Ridge. Physiological characterizations showed that it is a microaerobic chemolithomixotroph that can utilize sulfide, thiosulfate, elemental sulfur, tetrathionate, thiocyanate or hydrogen as energy sources and molecular oxygen as the sole electron acceptor. During thiosulfate oxidation, the strain produced extracellular sulfur globules 0.7–6.0 μm in diameter that were mainly composed of elemental sulfur and carbon. Some organic substrates including amino acids, tryptone, yeast extract, casamino acids, casein, acetate, formate, citrate, propionate, tartrate, succinate, glucose and fructose can also serve as carbon sources, but growth is weaker than under CO2 conditions, indicating that strain S5 prefers to be chemolithoautotrophic. None of the tested organic carbons could function as energy sources. Growth tests under various conditions confirmed its adaption to a mesophilic mixing zone of hydrothermal vents in which vent fluid was mixed with cold seawater, preferring moderate temperatures (optimal 37°C, alkaline pH (optimal pH 8.0, microaerobic conditions (optimal 4% O2, and reduced sulfur compounds (e.g., sulfide, optimal 100 μM. Comparative genomics showed that strain S5 possesses more complex sulfur metabolism systems than other members of genus Hydrogenovibrio. The genes encoding the intracellular sulfur oxidation protein (DsrEF and assimilatory sulfate reduction were first reported in the genus Hydrogenovibrio. In summary, the versatility in energy and carbon sources, and unique physiological properties of this bacterium have facilitated its adaptation to deep

  5. Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

    Science.gov (United States)

    Ridley, W.I.; Perfit, M.R.; Josnasson, I.R.; Smith, M.F.

    1994-01-01

    The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85??49???W and 85??55???W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens' equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (< 10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. The precipitation of base-metal sulfides beneath the seafloor is probably a result of fluid mixing and cooling. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems

  6. Acid-base behavior in hydrothermal processing of wastes. 1997 annual progress report

    International Nuclear Information System (INIS)

    1997-01-01

    'A major obstacle to the development of hydrothermal technology for treating DOE wastes has been a lack of scientific knowledge of solution chemistry, thermodynamics and transport phenomena. The progress over the last year is highlighted in the following four abstracts from manuscripts which have been submitted to journals. The authors also have made considerable progress on a spectroscopic study of the acid-base equilibria of Cr(VI). They have utilized novel spectroscopic indicators to study acid-base equilibria up to 380 C. Until now, very few systems have been studied at such high temperatures, although this information is vital for hydrothermal processing of wastes. The pH values of aqueous solutions of boric acid and KOH were measured with the optical indicator 2-naphthol at temperatures from 300 to 380 C. The equilibrium constant Kb-l for the reaction B(OH)3 + OH - = B(OH) -4 was determined from the pH measurements and correlated with a modified Born model. The titration curve for the addition of HCl to sodium borate exhibits strong acid-strong base behavior even at 350 C and 24.1 MPa. At these conditions, aqueous solutions of sodium borate buffer the pH at 9.6 t 0.25. submitted to Ind. Eng. Chem. Res. Acetic Acid and HCl Acid-base titrations for the KOH-acetic acid or NH 3 -acetic acid systems were monitored with the optical indicator 2-naphthoic acid at 350 C and 34 MPa, and those for the HCl;Cl- system with acridine at 380 C and up to 34 MPa (5,000 psia ). KOH remains a much stronger base than NH,OH at high temperature. From 298 K to the critical temperature of water, the dissociation constant for HCl decreases by 13 orders of magnitude, and thus, the basicity of Cl - becomes significant. Consequently, the addition of NaCl to HCl raises the pH. The pH titration curves may be predicted with reasonable accuracy from the relevant equilibrium constants and Pitzer''s formulation of the Debye- Htickel equation for the activity coefficients.'

  7. Synthesis of hierarchical SnO{sub 2} nanoflowers with enhanced acetic acid gas sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Jin, W.X.; Ma, S.Y., E-mail: Jinwenxuan8756@163.com; Tie, Z.Z.; Li, W.Q.; Luo, J.; Cheng, L.; Xu, X.L.; Wang, T.T.; Jiang, X.H.; Mao, Y.Z.

    2015-10-30

    Highlights: • We use glycol and deionized water as solvent jointly. • Our products have good selectivity and excellent response to acetic acid. • We obtain different morphologies’ hierarchical SnO{sub 2} nanoflowers through changing the volume ratio of glycol and deionized water. - Abstract: Different morphologies hierarchical flower-like tin dioxide (SnO{sub 2}) nanostructures were fabricated by changing the volume ratio of glycol and de-ionized water (V{sub g}:V{sub w} = 0, 1:2, 1:1 and 2:1) under a template-free and low-cost hydrothermal method and subsequent calcinations. The architectures, morphologies and gas sensing performances of the products were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and gas-sensing measurement device. It can be observed that all the nanoflowers were composed of two-dimensional (2D) nanosheets, and the thickness of nanosheets is only about 9 nm when V{sub g}:V{sub w} = 1:1. The sensor based on the product of V{sub g}:V{sub w} = 1:1 exhibited excellent gas sensing performance toward 500 ppm acetic acid at 260 °C, and the response value of this sensor was about 153.6, which was above 7.5 times higher than that of ammonia (about 20.3). In addition, the 3D flower-like SnO{sub 2} nanostructures exhibited not only high response and selectivity to ppm level acetone, but also fast response and recovery time within 10 s, demonstrating it can be used as a potential candidate for detecting acetic acid. Finally, the possible formation mechanism was proposed, too.

  8. EFFECTS OF HEAT-FLOW AND HYDROTHERMAL FLUIDS FROM ...

    African Journals Online (AJOL)

    Volcanic intrusions and hydrothermal activity have modified the diagenetic minerals. In the Ulster Basin, UK, most of the authigenic mineralization in the Permo-Triassic sandstones pre-dated tertiary volcanic intrusions. The hydrothermal fluids and heat-flow from the volcanic intrusions did not affect quartz and feldspar ...

  9. Hydrothermal Processes in the Archean - New Insights from Imaging Spectroscopy

    NARCIS (Netherlands)

    Ruitenbeek, F.J.A. van

    2007-01-01

    The aim of this research was to gain new insights in fossil hydrothermal systems using airborne imaging spectroscopy. Fossil submarine hydrothermal systems in Archean greenstone belts and other geologic terranes are important because of their relationship with volcanic massive sulfide (VMS) mineral

  10. Levulinic acid from orange peel waste by hydrothermal carbonization (HTC)

    NARCIS (Netherlands)

    Puccini, Monica; Licursi, Domenico; Stefanelli, Eleonora; Vitolo, Sandra; Galletti, Anna Maria Raspolli; Heeres, Hero Jan

    2016-01-01

    With the awareness of the need for optimal and sustainable use of natural resources, hydrothermal treatment of biomass and biomass waste for energy and resource recovery has received increasing attention. The hydrothermal carbonization (HTC) of a biomass is achieved using water as the reaction

  11. Hydrothermal stability of microporous silica and niobia-silica membranes

    NARCIS (Netherlands)

    Boffa, V.; Blank, David H.A.; ten Elshof, Johan E.

    2008-01-01

    The hydrothermal stability of microporous niobia–silica membranes was investigated and compared with silica membranes. The membranes were exposed to hydrothermal conditions at 150 and 200 °C for 70 h. The change of pore structure before and after exposure to steam was probed by single-gas permeation

  12. 21 CFR 522.2477 - Trenbolone acetate and estradiol.

    Science.gov (United States)

    2010-04-01

    ... mg trenbolone acetate and 4 mg estradiol, and 1 pellet containing 29 mg tylosin tartrate) per implant... estradiol, and 1 pellet containing 29 mg tylosin tartrate) per implant dose. (F) 80 mg trenbolone acetate... trenbolone acetate and 4 mg estradiol, and 1 pellet containing 29 mg tylosin tartrate) per implant dose. (G...

  13. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    Science.gov (United States)

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  14. Air-oxidized linalyl acetate - an emerging fragrance allergen?

    Science.gov (United States)

    Hagvall, Lina; Berglund, Victoria; Bråred Christensson, Johanna

    2015-04-01

    Linalyl acetate is a fragrance chemical that is prone to autoxidation. Exposure to linalyl acetate occurs through cosmetic products and essential oils, but is difficult to assess, as linalyl acetate is not labelled in the EU. To investigate the frequencies of contact allergy to oxidized linalyl acetate among dermatitis patients, and to investigate the autoxidation of linalyl acetate in terms of hydroperoxide formation and sensitization potency. Hydroperoxide formation in air-exposed linalyl acetate was determined with high-performance liquid chromatography. The sensitization potencies of hydroperoxides were determined with the local lymph node assay. One thousand seven hundred and seventeen patients were patch tested with oxidized linalyl acetate at 6.0% in petrolatum. Of the patients, 2.2% showed positive reactions to oxidized linalyl acetate. Forty-three per cent of the positive patients also had positive patch test reactions to other fragrance markers. Linalyl acetate hydroperoxides were detected early in the autoxidation process, and accumulated to a concentration of 37% after 42 weeks of air exposure. The linalyl acetate hydroperoxides were classified as moderate sensitizers. The frequency of positive reactions to oxidized linalyl acetate is comparable to that of previously studied oxidized fragrance terpenes. Oxidized linalyl acetate could thus be a common fragrance contact allergen. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate in wine.

    Science.gov (United States)

    Khopkar, Yashdeep; Kojtari, Arben; Swearer, Dayne; Zivanovic, Sandra; Ji, Hai-Feng

    2014-09-01

    We report the application of perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate. The conductivity of the crystalline nano/microwires increases quickly and selectively in the presence of ethyl acetate vapor, but not with water, acid and alcohol vapors, suggesting that the nanowires of PTCDI may be used for monitoring ethyl acetate during a wine manufacturing process.

  16. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  17. Avalanches in Mn12-Acetate: ``Magnetic Burning"

    Science.gov (United States)

    McHugh, Sean; Suzuki, Y.; Graybill, D.; Sarachik, M. P.; Avraham, N.; Myasoedov, Y.; Shtrikman, H.; Zeldov, E.; Bagai, R.; Chakov, N. E.; Christou, G.

    2006-03-01

    From local time-resolved measurements of fast reversal of the magnetization in single crystals of the molecular magnet Mn12-acetate, we have shown[1] that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity roughly two orders of magnitude smaller than the speed of sound. This phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance. The propagation speed of the avalanche depends on the energy stored in each molecule, which can be controlled and tuned using an external magnetic field. We report studies of propagation speed with different external fields in Mn12-acetate. [1] Yoko Suzuki, M.P. Sarachik, E.M. Chudnovsky, S. McHugh, R. Gonzalez-Rubio, N. Avraham, Y. Myasoedov, H. Shtrikman, E. Zeldov, N.E. Chakov and G. Christou, Phys. Rev. Lett. 95, 147201 (2005).

  18. Acetate in Oz: Some Strategic Moves

    Directory of Open Access Journals (Sweden)

    Colin Webb

    2005-08-01

    Full Text Available I would like to add my voice to the words of congratulations and thanks to the British Library for organising this forum, and for their generosity in making it possible for me to come across the world to be part of it. The issues we are discussing today have an importance extending beyond cellulose acetate, as they reflect our ability as custodians to deal with common threats to the documentary heritage we are charged with preserving. As I will argue later, we need to see this situation in the context of the full range of preservation management issues that face our institutions. While it imposes a burden and a challenge on us as preservation managers, it also presents opportunities to sort out some things that have needed attention for some time. I have been asked to talk about problems with cellulose acetate microfilm collections in Australia, and specifically the strategies – both national and local – that have been adopted or at least explored in response to those problems. In the time I have I will not be going into any of these in great detail, but I hope I can give you some sense of the situation down under, and perhaps draw out a few issues that might make this more than just an ‘us too’ session! One thing to emphasise from the start is that we have had a number of goes at dealing with acetate microfilm collections: it is not a newly discovered problem in Australia. One significant context in which we have been working is that of a national strategy for all kinds of cellulose acetate collection materials. Explaining this national strategy will form a major part of my presentation, with issues and approaches specific to microfilm discussed towards the end.

  19. Hydrothermal carbonization and torrefaction of grape pomace: a comparative evaluation.

    Science.gov (United States)

    Pala, Mehmet; Kantarli, Ismail Cem; Buyukisik, Hasan Baha; Yanik, Jale

    2014-06-01

    Grape pomace was treated by hydrothermal carbonization (sub-critical water, 175-275°C) and torrefaction (nitrogen atmosphere, 250 and 300°C), with mass yield of solid product (char) ranging between 47% and 78%, and energy densification ratio to 1.42-1.15 of the original feedstock. The chars were characterised with respect to their fuel properties, morphological and structural properties and combustion characteristics. The hydrothermal carbonization produced the char with greater energy density than torrefaction. The chars from torrefaction were found to be more aromatic in nature than that from hydrothermal carbonization. Hydrothermal carbonization process produced the char having high combustion reactivity. Most interesting was the finding that aqueous phase from hydrothermal carbonization had antioxidant activity. The results obtained in this study showed that HTC appears to be promising process for a winery waste having high moisture content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Ultrasound-assisted dyeing of cellulose acetate.

    Science.gov (United States)

    Udrescu, C; Ferrero, F; Periolatto, M

    2014-07-01

    The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C. The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively. Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Potentiometric titrations in anhydrous acetic acid

    International Nuclear Information System (INIS)

    Le Port, L.

    1966-03-01

    The method used for studying anhydrous acetic acid is potentiometry with a glass electrode. We have in this way studied the titration of common inorganic acids (HClO 4 - HBr - H 2 SO 4 - HCl - HNO 3 - H 3 PO 4 ) and of some metallic salts. Furthermore we have shown that complex acids are formed between HCl and some metallic chlorides. An analysis of the titration curves for the inorganic acids against pyridinium chloride has made it possible to calculate a certain number of values for the dissociation pK of these acids and of the corresponding pyridinium salts. The titration of metallic perchlorates constitutes a method of studying the stability of acetates; we have thus been able to draw up a classification for some of these acetates. The metallic chlorides studied fall into two groups according to their behaviour in weak or strong acids. The differences have been explained on the basis of the role played by solvolysis. In the third part we have studied the acidic properties of mixtures of HCl with certain metallic chlorides. This work has demonstrated the existence, in certain cases, of acid complexes of the type (HCl) m MCl n . (author) [fr

  2. Powering prolonged hydrothermal activity inside Enceladus

    Science.gov (United States)

    Choblet, Gaël; Tobie, Gabriel; Sotin, Christophe; Běhounková, Marie; Čadek, Ondřej; Postberg, Frank; Souček, Ondřej

    2017-12-01

    Geophysical data from the Cassini spacecraft imply the presence of a global ocean underneath the ice shell of Enceladus1, only a few kilometres below the surface in the South Polar Terrain2-4. Chemical analyses indicate that the ocean is salty5 and is fed by ongoing hydrothermal activity6-8. In order to explain these observations, an abnormally high heat power (>20 billion watts) is required, as well as a mechanism to focus endogenic activity at the south pole9,10. Here, we show that more than 10 GW of heat can be generated by tidal friction inside the unconsolidated rocky core. Water transport in the tidally heated permeable core results in hot narrow upwellings with temperatures exceeding 363 K, characterized by powerful (1-5 GW) hotspots at the seafloor, particularly at the south pole. The release of heat in narrow regions favours intense interaction between water and rock, and the transport of hydrothermal products from the core to the plume sources. We are thus able to explain the main global characteristics of Enceladus: global ocean, strong dissipation, reduced ice-shell thickness at the south pole and seafloor activity. We predict that this endogenic activity can be sustained for tens of millions to billions of years.

  3. Hydrothermal Liquefaction of Wastewater Treatment Plant Solids

    Energy Technology Data Exchange (ETDEWEB)

    Billing, Justin M.

    2016-10-16

    Feedstock cost is the greatest barrier to the commercial production of biofuels. The merits of any thermochemical or biological conversion process are constrained by their applicability to the lowest cost feedstocks. At PNNL, a recent resource assessment of wet waste feedstocks led to the identification of waste water treatment plant (WWTP) solids as a cost-negative source of biomass. WWTP solids disposal is a growing environmental concern [1, 2] and can account for up to half of WWTP operating costs. The high moisture content is well-suited for hydrothermal liquefaction (HTL), avoiding the costs and parasitic energy losses associated with drying the feedstock for incineration. The yield and quality of biocrude and upgraded biocrude from WWTP solids is comparable to that obtained from algae feedstocks but the feedstock cost is $500-1200 less per dry ton. A collaborative project was initiated and directed by the Water Environment & Reuse Foundation (WERF) and included feedstock identification, dewatering, shipping to PNNL, conversion to biocrude by HTL, and catalytic hydrothermal gasification of the aqueous byproduct. Additional testing at PNNL included biocrude upgrading by catalytic hydrotreatment, characterization of the hydrotreated product, and a preliminary techno-economic analysis (TEA) based on empirical results. This short article will cover HTL conversion and biocrude upgrading. The WERF project report with complete HTL results is now available through the WERF website [3]. The preliminary TEA is available as a PNNL report [4].

  4. Acid catalyzed reactions of cyclohexanol in liquid phase

    OpenAIRE

    Liu, Yuanshuai

    2017-01-01

    Hydronium ions in aqueous phase catalyze the dehydration of cyclohexanol via monomolecular precursors. In confines such as zeolite pores they are more active than in water, which is caused by an enhanced association between the hydronium ion and alcohol, as well as a greater activation entropy. Alcohol dimers, forming in apolar solvents, reduce the rate of reaction by stabilizing the ground state. Alkylation of arene rings with cyclohexanol requires the formation of a cyclohexyl carbenium ion...

  5. KSF-SUPPORTED HETEROPOLY ACIDS CATALYZED ONE-POT ...

    African Journals Online (AJOL)

    Preferred Customer

    this transformation [7-24], have been used to circumvent some of the problems associated with the classical ... coupled plasma (ICP) atomic emission spectroscopy on a Spectro Ciros CCd spectrometer. (Germany). The morphology of supported catalyst was studied by scanning electron microscopy. (SEM) using XL30 ...

  6. Conversion of Cyclohexanone to Adipic Acid Catalyzed by Heteropoly Compounds

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2015-03-01

    Full Text Available Conversion of cyclohexanone to adipic acid using hydrogen peroxide as green oxidant catalyzed by heteropoly compounds i.e. H5[a-BW12O40] H4[a-SiW12O40] and H4[a-PVMo11O40] has been carried out systematically in one pot synthesis under mild condition. The product of adipic acid was characterized using GC-MS, FT-IR, 1H-NMR and 13C-NMR spectroscopy. The results show that cyclohexanone could be converted into adipic acid by using H5[a-BW12O40] H4[a-SiW12O40] as catalysts, whereas H4[a-PVMo11O40] did not shows catalytic activity in this reaction. The effect of reaction time gave adipic acid 41% for reaction time 7 h. The yield of adipic acid was 30% with melting point 149-151 °C. The oxidation temperature at 100 °C gave the highest adipic acid 48% was obtained. The FT-IR, 1H-NMR and 13C-NMR spectra of the product are well agreed to the adipic acid standard.

  7. Development of Fluorous Lewis Acid-Catalyzed Reactions

    Directory of Open Access Journals (Sweden)

    Joji Nishikido

    2006-08-01

    Full Text Available Organic synthetic methodology in the 21st century aims to conform to the principles of green sustainable chemistry (GSC and we may expect that in the future, the realization of GSC will be an important objective for chemical industries. An important aim of synthetic organic chemistry is to implement waste-free and environmentally-benign industrial processes using Lewis acids as versatile as aluminum choride. A key technological objective of our work in this area has been to achieve a “catalyst recycling system that utilizes the high activity and structural features of fluorous Lewis acid catalysts”. Thus, we have developed a series of novel fluorous Lewis acid catalysts, namely the ytterbium(III, scandium(III, tin(IV or hafnium(IV bis(perfluoroalkanesulfonylamides or tris(perfluoro- alkanesulfonylmethides. Our catalysts are recyclable and effective for acylations of alcohols and aromatics, Baeyer-Villiger reactions, direct esterifications and transesterifications in a fluorous biphasic system (FBS, in supercritical carbon dioxide and on fluorous silica gel supports.

  8. Organic acid catalyzed carbon aerogels with freeze-drying

    Science.gov (United States)

    Xu, Yuelong; Yan, Meifang; Liu, Zhenfa

    2017-09-01

    Carbon aerogels (CAs) were synthesized via a sol-gel process by condensation-polymerization of phloroglucinol, resorcinol and formaldehyde using 2,4-dihydroxybenzoic acid as catalyst with freeze-drying. The effects of the freeze-drying method on the texture and pore structure were studied. Meanwhile the structure of carbon aerogels was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and a surface-area analyzer. The results show that the freeze-drying method and acid catalyst were good for the specific surface area of carbon aerogel, up to 765m2 g-1, and pore size distribution.

  9. Acetic acid sclerotheraphy of renal cysts

    International Nuclear Information System (INIS)

    Hong, Hoon Pyo; Oh, Joo Hyeong; Yoon, Yup; Kong, Keun Young; Kim, Eui Jong; Goo, Jang Sung

    1998-01-01

    Sclerotherapy for renal cysts was performed, using 50% acetic acid as new sclerosing agent. We report the methods and results of this procedure. Fifteen patients underwent sclerotherapy for renal cyst, using 50% acetic acid. Because four patients were lost to follow-up, only 11 of the 15 were included in this study. The renal cysts, including one infected case, were diagnosed by ultrasonograpy (n=3D10) ormagnetic resonance imaging (n=3D1). The patient group consisted of four men and seven women(mean age, 59 years; range, 23-77). At first, the cyst was completely aspirated, and 25 volume% of aspirated volume was replaced with 50% sterile acetic acid through the drainage catheter. During the follwing 20 minutes, the patient changed position, and the acetic acid was then removed from the cyst. Finally, the drainage catheter was removed, after cleaning the cyst with saline. After treatment of infection by antibiotics and catheter drainage for 7 days, sclerotherapy in the infected case followed the same procedure. In order to observe changes in the size of renal cysts and recurrence, all patients were followed up by ultrasound between 2 and 8 months. We defined response to therapy as follows:complete regression as under 5 volume%, partial regression as 5-50 volume% and no response as more than 50 volume% of initial cyst volume. No clinically significant complication occured during the procedures or follow-up periods. All cysts regressed completely during follow-up of 8 months. Complete regression occurred as follows: two cysts at 2 months, seven cysts at 4 months, two cysts at 6 months. Two cysts showed residues at the last follow-up, at 4 and 6 months, respectively. The volume of residual cysts decreased to under 5 volume% of initial volume, however. Completely regressed cysts did not recurr during follow-up. Acetic acid sclerotherapy for renal cysts showed good results, regardless of the dilution of sclerosing agent with residual cyst fluid, and no significant

  10. The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation

    Science.gov (United States)

    Teske, Andreas; de Beer, Dirk; McKay, Luke J.; Tivey, Margaret K.; Biddle, Jennifer F.; Hoer, Daniel; Lloyd, Karen G.; Lever, Mark A.; Røy, Hans; Albert, Daniel B.; Mendlovitz, Howard P.; MacGregor, Barbara J.

    2016-01-01

    The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heat flow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for comprehensive surveys of the wider spreading region. PMID:26925032

  11. Lipase Mediated Isoamyl Acetate Synthesis in Solvent-Free System Using Vinyl Acetate as Acyl Donor

    Directory of Open Access Journals (Sweden)

    Annapurna Kumari

    2009-01-01

    Full Text Available Synthesis of isoamyl acetate, a flavour ester extensively used in food industry, has been carried out in a solvent-free system. In the present study, an attempt has been made to enhance the isoamyl acetate synthesis yield by transesterification of isoamyl alcohol with vinyl acetate using immobilized Rhizopus oryzae NRRL 3562 lipase. In the present synthesis, substrates had no inhibitory effect on immobilized lipase. The effects of various reaction parameters on isoamyl acetate synthesis were studied and maximum conversion was achieved at 16 % (by mass per volume of immobilized lipase, 40 °C and 200 rpm. Under these conditions, 8-hour reaction time was sufficient to reach a high ester conversion of 95 % with 0.5 mol/L of isoamyl alcohol. The structure of the transesterified product was confirmed by infrared and nuclear magnetic resonance spectroscopic studies. Immobilized lipase had Km and vmax values of 306.53 mmol/L and 99 µmol/(h·g respectively, for isoamyl acetate synthesis in a solvent-free system.

  12. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided.

  13. Two-dimensional NMR evidence for cleavage of lignin and xylan substituents in wheat straw through hydrothermal pretreatment and enzymatic hydrolysis

    DEFF Research Database (Denmark)

    Yelle, Daniel J.; Kaparaju, Laxmi-Narasimha Prasad; Hunt, Christopher G.

    2013-01-01

    correlation spectroscopy, via an heteronuclear single quantum coherence experiment, revealed substantial lignin β-aryl ether cleavage, deacetylation via cleavage of the natural acetates at the 2-O- and 3-O-positions of xylan, and uronic acid depletion via cleavage of the (1 → 2)-linked 4-O....... g., further deacylation revealed by the depletion in ferulate and p-coumarate structures). Supplementary chemical analyses showed that the hydrothermal pretreatment increased the cellulose and lignin concentration with partial removal of extractives and hemicelluloses. The subsequent enzymatic...

  14. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    Science.gov (United States)

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-08

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. © 2016 American Institute of Chemical Engineers.

  15. Thermodynamics of hydrothermal systems with oxalate ion

    Science.gov (United States)

    Khodakovsky, I. L.; Devina, O. A.

    2009-04-01

    The geochemical and industrial significance of oxalates have led to great interest in the behavior of oxalate ion in hydrothermal systems. On the basis of a study by G.B. Naumov et al (1971) of gaseous-liquid inclusions it is shown that whewellite (CaC2O4•H2O) which was found in quartz-calcite-fluorite veins in the uranium ore deposit of the Eastern Transbaikal region was formed at temperatures about 150°C and pressure CO2 of 600-860 atm. The isotopic composition of carbon for these hydrothermal whewellite samples was determined by Galimov et al (1975): Delta13C from -1.56 to -2.22%. In a continuation of the study of organic-acid-water-rock interactions the thermodynamics of hydrothermal equilibriums for the systems Ox-H, Ox-H-Ca, Ox-H-Mg (where Ox = C2O42-), are described up to 200°C. The key network reactions and compounds related to the aqueous ion C2O42- are discussed and used to define the key values. The critical evaluation of thermodynamic properties for this ion is a part of the development of the new key values system for the joint thermodynamic database in the Internet. The evaluation involves the analysis of the enthalpy changes, Gibbs energy changes, and the entropy calculations for all key substances in the key network. A consistent set of thermodynamic property values is given for α-H2C2O4(cr), β-H2C2O4(cr), H2C2O4•H2O(cr), CaC2O4(cr), CaC2O4•H2O(cr,whewellite), NaC2O4(cr,natroxalate), MgC2O4•2H2O(cr,glushinskite) and aqueous species C2O42-, HC2O4-, H2C2O4°, CaC2O4°. This study was funded by Russian Foundation for Basic Research (project N 07-05-01108).

  16. Entropy Production in Convective Hydrothermal Systems

    Science.gov (United States)

    Boersing, Nele; Wellmann, Florian; Niederau, Jan

    2016-04-01

    Exploring hydrothermal reservoirs requires reliable estimates of subsurface temperatures to delineate favorable locations of boreholes. It is therefore of fundamental and practical importance to understand the thermodynamic behavior of the system in order to predict its performance with numerical studies. To this end, the thermodynamic measure of entropy production is considered as a useful abstraction tool to characterize the convective state of a system since it accounts for dissipative heat processes and gives insight into the system's average behavior in a statistical sense. Solving the underlying conservation principles of a convective hydrothermal system is sensitive to initial conditions and boundary conditions which in turn are prone to uncertain knowledge in subsurface parameters. There exist multiple numerical solutions to the mathematical description of a convective system and the prediction becomes even more challenging as the vigor of convection increases. Thus, the variety of possible modes contained in such highly non-linear problems needs to be quantified. A synthetic study is carried out to simulate fluid flow and heat transfer in a finite porous layer heated from below. Various two-dimensional models are created such that their corresponding Rayleigh numbers lie in a range from the sub-critical linear to the supercritical non-linear regime, that is purely conductive to convection-dominated systems. Entropy production is found to describe the transient evolution of convective processes fairly well and can be used to identify thermodynamic equilibrium. Additionally, varying the aspect ratio for each Rayleigh number shows that the variety of realized convection modes increases with both larger aspect ratio and higher Rayleigh number. This phenomenon is also reflected by an enlarged spread of entropy production for the realized modes. Consequently, the Rayleigh number can be correlated to the magnitude of entropy production. In cases of moderate

  17. Detoxification of biomass derived acetate via metabolic conversion to ethanol, acetone, isopropanol, or ethyl acetate

    Energy Technology Data Exchange (ETDEWEB)

    Sillers, William Ryan; Van Dijken, Hans; Licht, Steve; Shaw, IV, Arthur J.; Gilbert, Alan Benjamin; Argyros, Aaron; Froehlich, Allan C.; McBride, John E.; Xu, Haowen; Hogsett, David A.; Rajgarhia, Vineet B.

    2017-03-28

    One aspect of the invention relates to a genetically modified thermophilic or mesophilic microorganism, wherein a first native gene is partially, substantially, or completely deleted, silenced, inactivated, or down-regulated, which first native gene encodes a first native enzyme involved in the metabolic production of an organic acid or a salt thereof, thereby increasing the native ability of said thermophilic or mesophilic microorganism to produce lactate or acetate as a fermentation product. In certain embodiments, the aforementioned microorganism further comprises a first non-native gene, which first non-native gene encodes a first non-native enzyme involved in the metabolic production of lactate or acetate. Another aspect of the invention relates to a process for converting lignocellulosic biomass to lactate or acetate, comprising contacting lignocellulosic biomass with a genetically modified thermophilic or mesophilic microorganism.

  18. Non-traditional Stable Isotope Systematics of Seafloor Hydrothermal Systems

    Science.gov (United States)

    Rouxel, O. J.

    2009-05-01

    Seafloor hydrothermal activity at mid-ocean ridges is one of the fundamental processes controlling the chemistry of the oceans and the altered oceanic crust. Past studies have demonstrated the complexity and diversity of seafloor hydrothermal systems and have highlighted the importance of subsurface environments in controlling the composition of hydrothermal fluids and mineralization types. Traditionally, the behavior of metals in seafloor hydrothermal systems have been investigated by integrating results from laboratory studies, theoretical models, mineralogy and fluid and mineral chemistry. Isotope ratios of various metals and metalloids, such as Fe, Cu, Zn, Se, Cd and Sb have recently provided new approaches for the study of seafloor hydrothermal systems. Despite these initial investigations, the cause of the isotopic variability of these elements remains poorly constrained. We have little understanding of the isotope variations between vent types (black or white smokers) as well as the influence of source rock composition (basalt, felsic or ultrabasic rocks) and alteration types. Here, I will review and present new results of metal isotope systematics of seafloor hydrothermal systems, in particular: (1) determination of empirical isotope fractionation factors for Zn, Fe and Cu-isotopes through isotopic analysis of mono-mineralic sulfide grains lining the internal chimney wall in contact with hydrothermal fluid; (2) comparison of Fe- and Cu-isotope signatures of vent fluids from mid- oceanic and back-arc hydrothermal fields, spanning wide ranges of pH, temperature, metal concentrations and contributions of magmatic fluids enriched in SO2. Ultimately, the use of complementary non-traditional stable isotope systems may help identify and constrain the complex interactions between fluids,minerals, and organisms in seafloor hydrothermal systems.

  19. Aerobic oxidation of aqueous ethanol using heterogeneous gold catalysts: Efficient routes to acetic acid and ethyl acetate

    DEFF Research Database (Denmark)

    Jørgensen, Betina; Christiansen, Sofie Egholm; Thomsen, M.L.D.

    2007-01-01

    The aerobic oxidation of aqueous ethanol to produce acetic acid and ethyl acetate was studied using heterogeneous gold catalysts. Comparing the performance of Au/MgAl2O4 and Au/TiO2 showed that these two catalysts exhibited similar performance in the reaction. By proper selection of the reaction......, the possibilities for producing ethyl acetate by the aerobic oxidation of ethanol is also studied. At low ethanol concentrations, the main product is acetic acid; at concentrations >60 wt%, it is ethyl acetate....... conditions, yields of 90-95% of acetic acid could be achieved at moderate temperatures and pressures. Based on our findings, a reaction pathway for the catalytic oxidation of ethanol via acetaldehyde to acetic acid is proposed, and the rate-determining step (RDS) in the mechanism is found to be the (possibly...

  20. Hydrothermal conditions around a radioactive waste repository

    International Nuclear Information System (INIS)

    Thunvik, R.; Braester, C.

    1981-12-01

    Numerical solutions for the hydrothermal conditions around a hard rock repository for nuclear fuel waste are presented. The objective of the present investigation is to illustrate in principle the effect of heat released from a hypothetical radioactive waste repository with regard to anisotropy in the rock permeability. Permeability and porosity are assumed to be constant or to decrease exponentially with depth. The hypothetical repository is situated below a horizontal ground surface or below the crest of a hill, and it is assumed that the water table follows the topography. Major interest in the analysis is directed towards the influence of anisotropy in the permeability on the flow patterns and travel times for water particles, being traced from the repository to the ground surface. The presented results show that anisotropy in the permeability may have a significant influence on the flow conditions around the repository and subsequently also on the travel times from the repository. (Authors)

  1. Tuning magnetization avalanches in Mn12-acetate

    Science.gov (United States)

    Wen, Bo; McHugh, S.; Ma, Xiang; Sarachik, M. P.; Myasoedov, Y.; Shtrikman, H.; Zeldov, E.; Bagai, R.; Christou, G.

    2009-03-01

    We report the results of a systematic study of magnetic avalanches (abrupt magnetization reversals) in the molecular magnet Mn12-acetate using a micron-sized Hall sensor array. Measurements were taken for: (a) fixed magnetic field (constant barrier against spin reversal); and (b) fixed energy release obtained by adjusting the barrier and δM. A detailed comparison with the theory of magnetic deflagration of Garanin and Chudnovsky [1] will be presented and discussed. [1] D. A. Garanin and E. M. Chudnovsky, Phys. Rev. B 76, 054410 (2007)

  2. Potential biomass in deep-sea hydrothermal vent ecosystem

    Science.gov (United States)

    Nakamura, K.; Takai, K.

    2012-12-01

    Since the first discovery of black smoker vents hosting chemosynthetic macrofaunal communities (Spiess et al., 1980), submarine hydrothermal systems and associated biota have attracted interest of many researchers (e.g., Humphris et al., 1995; Van Dover, 2000; Wilcock et al., 2004). In the past couple of decades, particular attention has been paid to chemolithoautotrophic microorganisms that sustain the hydrothermal vent-endemic animal communities as the primary producer. This type of microorganisms obtains energy from inorganic substances (e.g., sulfur, hydrogen, and methane) derived from hydrothermal vent fluids, and is often considered as an important modern analogue to the early ecosystems of the Earth as well as the extraterrestrial life in other planets and moons (e.g., Jannasch and Mottl, 1985; Nealson et al., 2005; Takai et al., 2006). Even today, however, the size of this type of chemosynthetic deep-sea hydrothermal vent ecosystem is largely unknown. Here, we present geophysical and geochemical constraints on potential biomass in the deep-sea hydrothermal vent ecosystem. The estimation of the potential biomass in the deep-sea hydrothermal vent ecosystem is based on hydrothermal fluid flux calculated from heat flux (Elderfield and Schltz, 1996), maximum chemical energy available from metabolic reactions during mixing between hydrothermal vent fluids and seawater (McCollom, 2007), and maintenance energy requirements of the chemolithoautotrophic microorganisms (Hoehler, 2004). The result shows that the most of metabolic energy sustaining the deep-sea hydrothermal vent ecosystem is produced by oxidation reaction of reduced sulfur, although some parts of the energy are derived from hydrogenotrophic and methanotrophic reactions. The overall total of the potential biomass in deep-sea hydrothermal vent ecosystem is calculated to be much smaller than that in terrestrial ecosystems including terrestrial plants. The big difference in biomass between the

  3. Coupling hydrothermal liquefaction and anaerobic digestion for energy valorization from model biomass feedstocks.

    Science.gov (United States)

    Posmanik, Roy; Labatut, Rodrigo A; Kim, Andrew H; Usack, Joseph G; Tester, Jefferson W; Angenent, Largus T

    2017-06-01

    Hydrothermal liquefaction converts food waste into oil and a carbon-rich hydrothermal aqueous phase. The hydrothermal aqueous phase may be converted to biomethane via anaerobic digestion. Here, the feasibility of coupling hydrothermal liquefaction and anaerobic digestion for the conversion of food waste into energy products was examined. A mixture of polysaccharides, proteins, and lipids, representing food waste, underwent hydrothermal processing at temperatures ranging from 200 to 350°C. The anaerobic biodegradability of the hydrothermal aqueous phase was examined through conducting biochemical methane potential assays. The results demonstrate that the anaerobic biodegradability of the hydrothermal aqueous phase was lower when the temperature of hydrothermal processing increased. The chemical composition of the hydrothermal aqueous phase affected the anaerobic biodegradability. However, no inhibition of biodegradation was observed for most samples. Combining hydrothermal and anaerobic digestion may, therefore, yield a higher energetic return by converting the feedstock into oil and biomethane. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Long-term continuous evolution of acetate resistant Acetobacter aceti.

    Science.gov (United States)

    Steiner, Peter; Sauer, Uwe

    2003-10-05

    Elevated concentrations of cytotoxic acetate are found in many environmental niches, and few species are relatively resistant to acetate. In particular the high-level acetate resistance of so-called acetic acid bacteria that occurs in industrial settings must be constantly selected for. To investigate the nature of such high-level resistance, we grew the moderately acetate-resistant Acetobacter aceti wild-type and acetate-sensitive Escherichia coli in long-term continuous cultures with increasing acetate concentrations at near neutral pH. While E. coli did not acquire any significant resistance after 125 generations of selection, A. aceti evolved the capability to grow at acetate concentrations exceeding 50 g/L within 240 generations. This phenotype was found to be stable for several generations in the absence of selective pressure, hence must be genetically determined. Intracellular acetate concentrations were significantly lower in evolved A. aceti, when compared to wild-type A. aceti and E. coli, indicating that cytoplasmatic anion accumulation is an important component of acetate toxicity. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 40-44, 2003.

  5. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii.

    Science.gov (United States)

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2016-04-01

    Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic-acid-tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo-lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin-treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress. © 2015 Wiley Periodicals, Inc.

  6. Glycerol transesterification with ethyl acetate to synthesize acetins using ethyl acetate as reactant and entrainer

    Directory of Open Access Journals (Sweden)

    Amin Shafiei

    2017-03-01

    Full Text Available Transesterification of glycerol with ethyl acetate was performed over acidic catalysts in the batch and semi-batch systems. Ethyl acetate was used as reactant and entrainer to remove the produced ethanol during the reaction, through azeotrope formation. Since the azeotrope of ethyl acetate and ethanol forms at 70 oC, all the experiments were performed at this temperature. Para-toluene sulfonic acid, sulfuric acid, and Amberlyst 36 were used as catalyst. The effect of process parameters including ethyl acetate to glycerol molar ratio (6-12, reaction time (3-9 h, and the catalyst to glycerol weight (2.5-9.0%, on the conversion and products selectivities were investigated. Under reflux conditions, 100% glycerol conversion was obtained with 45%, 44%, and 11% selectivity to monoacetin, diacetin, and triacetin, respectively. Azeotropic reactive distillation led to 100% conversion of glycerol with selectivities of 3%, 48% and 49% for monoacetin, diacetin, and triacetin. During the azeotropic reactive distillation, it was possible to remove ethanol to shift the equilibrium towards diacetin and triacetin. Therefore, the total selectivity to diacetin and triacetin was increased from 55% to 97% through azeotropic distillation.

  7. SPECTROPHOTOMETRIC AND LUMINESCENCE DETERMINATION OF ABIRATERONE ACETATE

    Directory of Open Access Journals (Sweden)

    I. I. Leonenko

    2015-02-01

    Full Text Available The methods of the spectrophotometric (SP and fluorimetric (FL determination of a new anticancer drug, abiraterone acetate (AA have been proposed. SP method is based on measurement of light absorbance of ethanol solution of AA at a wavelength 253 nm. The calibration graph (CG is linear in the concentration range 1.0–30.0 AA μg/ml, the limit of detection (LOD is 0.35 μg/ml.Two versions of FL determination of AA: on its native luminescence (λex=253 nm; λlum=350  nm and on quenching sensitized luminescence of the terbium(III complex by abiraterone acetate have been developed. CG in the case of native fluorescence is linear in the range of 0.05–7.0 μg/ml, Stern-Folmer calibration curve is linear in the interval of concentrations of AA 0.5– 70 μg/ml. LOD of both fluorescent methods is 0.017 μg/ml.

  8. Immunotoxicity of trenbolone acetate in Japanese quail

    Science.gov (United States)

    Quinn, M.J.; McKernan, M.; Lavoie, E.T.; Ottinger, M.A.

    2007-01-01

    Trenbolone acetate is a synthetic androgen that is currently used as a growth promoter in many meat-exporting countries. Despite industry laboratories classifying trenbolone as nonteratogenic, data showed that embryonic exposure to this androgenic chemical altered development of the immune system in Japanese quail. Trenbolone is lipophilic, persistent, and released into the environment in manure used as soil fertilizer. This is the first study to date to assess this chemical's immunotoxic effects in an avian species. A one-time injection of trenbolone into yolks was administered to mimic maternal deposition, and subsequent effects on the development and function of the immune system were determined in chicks and adults. Development of the bursa of Fabricius, an organ responsible for development of the humoral arm of the immune system, was disrupted, as indicated by lower masse, and smaller and fewer follicles at day 1 of hatch. Morphological differences in the bursas persisted in adults, although no differences in either two measures of immune function were observed. Total numbers of circulating leukocytes were reduced and heterophil-lymphocyte ratios were elevated in chicks but not adults. This study shows that trenbolone acetate is teratogenic and immunotoxic in Japanese quail, and provides evidence that the quail immune system may be fairly resilient to embryonic endocrine-disrupting chemical-induced alterations following no further exposure posthatch.

  9. Electrochemical Partial Reforming of Ethanol into Ethyl Acetate Using Ultrathin Co3O4 Nanosheets as a Highly Selective Anode Catalyst.

    Science.gov (United States)

    Dai, Lei; Qin, Qing; Zhao, Xiaojing; Xu, Chaofa; Hu, Chengyi; Mo, Shiguang; Wang, Yu Olivia; Lin, Shuichao; Tang, Zichao; Zheng, Nanfeng

    2016-08-24

    Electrochemical partial reforming of organics provides an alternative strategy to produce valuable organic compounds while generating H2 under mild conditions. In this work, highly selective electrochemical reforming of ethanol into ethyl acetate is successfully achieved by using ultrathin Co3O4 nanosheets with exposed (111) facets as an anode catalyst. Those nanosheets were synthesized by a one-pot, templateless hydrothermal method with the use of ammonia. NH3 was demonstrated critical to the overall formation of ultrathin Co3O4 nanosheets. With abundant active sites on Co3O4 (111), the as-synthesized ultrathin Co3O4 nanosheets exhibited enhanced electrocatalytic activities toward water and ethanol oxidations in alkaline media. More importantly, over the Co3O4 nanosheets, the electrooxidation from ethanol to ethyl acetate was so selective that no other oxidation products were yielded. With such a high selectivity, an electrolyzer cell using Co3O4 nanosheets as the anode electrocatalyst and Ni-Mo nanopowders as the cathode electrocatalyst has been successfully built for ethanol reforming. The electrolyzer cell was readily driven by a 1.5 V battery to achieve the effective production of both H2 and ethyl acetate. After the bulk electrolysis, about 95% of ethanol was electrochemically reformed into ethyl acetate. This work opens up new opportunities in designing a material system for building unique devices to generate both hydrogen and high-value organics at room temperature by utilizing electric energy from renewable sources.

  10. Direct use of hydrothermal energy: a review of environmental aspects

    Energy Technology Data Exchange (ETDEWEB)

    O' Banion, K.; Layton, D.

    1981-08-28

    The potential environmental impacts of the exploration, development, and production of hydrothermal geothermal energy for direct use applications are reviewed and evaluated. Mitigation strategies and research and development needs are included. (MHR)

  11. Whole Algae Hydrothermal Liquefaction: 2014 State of Technology

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Susanne B.; Zhu, Yunhua; Snowden-Swan, Lesley J.; Anderson, Daniel; Hallen, Richard T.; Schmidt, Andrew J.; Albrecht, Karl O.; Elliott, Douglas C.

    2014-07-30

    This report describes the base case yields and operating conditions for converting whole microalgae via hydrothermal liquefaction and upgrading to liquid fuels. This serves as the basis against which future technical improvements will be measured.

  12. Hydrothermal Carbonization of Seaweed For Advanced Biochar Production

    Directory of Open Access Journals (Sweden)

    Prakoso Tirto

    2018-01-01

    Full Text Available Seaweed such as Eucheuma Cottonii is a potential source of biomaterialIts high moisture content makes it suitable for hydrothermal conversion process since it doesn’t need to utilize dry feedstock. The aim of this study is to convert the biomass of red seaweed Eucheuma Cottonii into alternative fuels and high value biomaterials using hydrothermal process. The hydrothermal process seaweed Eucheuma Cottonii produce two types of products, liquid product and char (solid. This research focus on the char product. The char from hydrothermal process was then activated using the tubular furnace. The yield for activated char is 7.5 % and results of SEM analysis of activated char showed the formation of allotropes carbon include carbon micro spheres, carbon micro fibres and graphene. These structures have encountered application in a wide range of technological fields, such as adsorption, catalysis, hydrogen storage or electronics.

  13. Development of a hydrothermal method to synthesize spherical ...

    African Journals Online (AJOL)

    Vis spectroscopy. Through these techniques, it was found that the pure ZnSe nanoparticles have a zinc blend structure and in a spherical form with average diameter of 30 nm. KEY WORDS: ZnSe, Nanosphere, Hydrothermal, Surfactant. Bull.

  14. Radionuclides in hydrothermal systems as indicators of repository conditions

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Flexser, S.; Smith, A.R.

    1990-11-01

    Hydrothermal systems in tuffaceous and older sedimentary rocks contain evidence of the interaction of radionuclides in fluids with rock matrix minerals and with materials lining fractures, in settings somewhat analogous to the candidate repository site at Yucca Mountain, NV. Earlier studies encompassed the occurrences of U and Th in a ''fossil'' hydrothermal system in tuffaceous rock of the San Juan Mountains volcanic field, CO. More recent and ongoing studies examine active hydrothermal systems in calderas at Long Valley, CA and Valles, NM. At the Nevada Test Site, occurrences of U and Th in fractured and unfractured rhyolitic tuff that was heated to simulate the introduction of radioactive waste are also under investigation. Observations to date suggest that U is mobile in hydrothermal systems, but that localized reducing environments provided by Fe-rich minerals and/or carbonaceous material concentrate U and thus attenuate its migration. 11 refs., 6 figs., 1 tab

  15. Fabrication of Gold Nanochains with Octreotide Acetate Template

    Directory of Open Access Journals (Sweden)

    Jing Zhou

    2013-01-01

    Full Text Available We described a facile method for assembly gold nanochains by using octreotide acetate as template in aqueous environment. In acidic solution, octreotide acetate was conferred positive charges and its structure changed to chain-like. The monodisperse negative gold nanoparticles were bound to the surface of octreotide acetate template by electrostatic attraction and the interaction of gold nanoparticles with amino acid residues (tryptophan and lysine. The fabricated gold nanostructure presented chain-like observed by transmission electron microscopy. The cytotoxicity of gold nanochains was examined by tetrazolium dye-based microtitration (MTT assay, which demonstrated significantly less toxicity than that of octreotide acetate alone. The MTT assay also reflected the combinative action between the gold nanoparticles with octreotide acetate. Our work lays the groundwork for developing octreotide acetate-templated nanomaterials that can be used as a building block for the creation of nanomaterials. Meanwhile, the harmfulless gold nanochains have great application prospects in the biomedical filed.

  16. Genetic dissection of acetic acid tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Geng, Peng; Xiao, Yin; Hu, Yun; Sun, Haiye; Xue, Wei; Zhang, Liang; Shi, Gui-Yang

    2016-09-01

    Dissection of the hereditary architecture underlying Saccharomyces cerevisiae tolerance to acetic acid is essential for ethanol fermentation. In this work, a genomics approach was used to dissect hereditary variations in acetic acid tolerance between two phenotypically different strains. A total of 160 segregants derived from these two strains were obtained. Phenotypic analysis indicated that the acetic acid tolerance displayed a normal distribution in these segregants, and suggested that the acetic acid tolerant traits were controlled by multiple quantitative trait loci (QTLs). Thus, 220 SSR markers covering the whole genome were used to detect QTLs of acetic acid tolerant traits. As a result, three QTLs were located on chromosomes 9, 12, and 16, respectively, which explained 38.8-65.9 % of the range of phenotypic variation. Furthermore, twelve genes of the candidates fell into the three QTL regions by integrating the QTL analysis with candidates of acetic acid tolerant genes. These results provided a novel avenue to obtain more robust strains.

  17. Novel technology for hydrothermal treatment of NPP evaporator concentrates

    International Nuclear Information System (INIS)

    Avramenko, Valentin; Dobrzhansky, Vitaly; Marinin, Dmitry; Sergienko, Valentin; Shmatko, Sergey

    2007-01-01

    A novel technology was developed for treatment of evaporator concentrates produced as a result of operation of evaporation devices comprising the main component of special water purification systems of nuclear power plants (NPP). The developed technology includes a hydrothermal (T=250-300 deg. C and P=80-120 bar) processing of evaporator concentrates in oxidation medium in order to destruct stable organic complexes of cobalt radionuclides and remove these radionuclides by oxide materials formed during such a processing. The cesium radionuclides contained in evaporator concentrates are removed by a conventional method-through application of one of the developed composite sorbents with ferrocyanides of transition metals used as active agents. Extensive laboratory studies of the processes occurring in evaporator concentrates under hydrothermal conditions were performed. It was shown that hydrothermal oxidation of evaporator concentrates has a number of advantages as compared to traditional oxidation methods (ozonization, photo-catalytic, electrochemical and plasma oxidation). A laboratory installation was built for the flow-type hydrothermal oxidation of NPP evaporator concentrates. The obtained experimental results showed good prospects for the developed method application. On the basis of the results obtained, a pilot installation of productivity up to 15 l/hour was developed and built in order to work out the technology of evaporator concentrates hydrothermal treatment. The pilot tests of the hydrothermal technology for evaporator concentrates hydrothermal treatment were performed for 6 months in 2006 at the 1. reactor unit of the Novovoronezhskaya NPP (Voronezh Region, Russia). Optimal technological regimes were determined, and estimations of the economic soundness of the technology were made. The advantages of the presented technology in terms of management of concentrated liquid radioactive wastes (LRW) at nuclear cycle facilities, as compared to other methods

  18. Volcano-hydrothermal energy research at white Island, New Zealand

    International Nuclear Information System (INIS)

    Allis, R.G.

    1994-01-01

    This paper presents the White Island (New Zealand) volcano-hydrothermal research project by the N.Z. DSIR and the Geological Survey of Japan, which is investigating the coupling between magmatic and geothermal systems. The first phase of this investigation is a geophysical survey of the crater floor of the andesite volcano, White Island during 1991/1992, to be followed by drilling from the crater floor into the hydrothermal system. (TEC). 4 figs., 8 refs

  19. The hydrothermal evolution of the Kawerau geothermal system, New Zealand

    Science.gov (United States)

    Milicich, S. D.; Chambefort, I.; Wilson, C. J. N.; Charlier, B. L. A.; Tepley, F. J.

    2018-03-01

    Hydrothermal alteration zoning and processes provide insights into the evolution of heat source(s) and fluid compositions associated with geothermal systems. Traditional petrological techniques, combined with hydrothermal alteration studies, stable isotope analyses and geochronology can resolve the nature of the fluids involved in hydrothermal processes and their changes through time. We report here new findings along with previous unpublished works on alteration patterns, fluid inclusion measurements and stable isotope data to provide insights into the thermal and chemical evolution of the Kawerau geothermal system, New Zealand. These data indicate the presence of two hydrothermal events that can be coupled with chronological data. The earlier period of hydrothermal activity was initiated at 400 ka, with the heat driving the hydrothermal system inferred to be from the magmatic system that gave rise to rhyolite lavas and sills of the Caxton Formation. Isotopic data fingerprint fluids attributed to this event as meteoric, indicating that the magma primarily served as a heat source driving fluid circulation, and was not releasing magmatic fluids in sufficient quantity to affect the rock mineralogy and thus inferred fluid compositions. The modern Kawerau system was initiated at 16 ka with hydrothermal eruptions linked to shallow intrusion of magma at the onset of activity that gave rise to the Putauaki andesite cone. Likely associated with this later event was a pulse of magmatic CO2, resulting in large-scale deposition of hydrothermal calcite enriched in 18O. Meteoric water-dominated fluids subsequently overwhelmed the magmatic fluids associated with this 18O-rich signature, and both the fluid inclusion microthermometry and stable isotope data reflect a change to the present-day fluid chemistry of low salinity, meteoric-dominated waters.

  20. Proton conductivity and relaxation properties of chitosan-acetate films

    International Nuclear Information System (INIS)

    Prokhorov, E.; Luna-Bárcenas, G.; González-Campos, J.B.; Kovalenko, Yu.; García-Carvajal, Z.Y.; Mota-Morales, J.

    2016-01-01

    Graphical abstract: Temperature dependence of conductivity, the number of density and proton mobility in chitosan-acetate film. - Highlights: • DD, conductivity, Vogel temperature dependent on the concentration of acetic acid. • Proton conductivity of CS-acetate films interpreted using two Grotthuss mechanisms. • Transformation between two mechanisms observed at the glass transition temperature. - Abstract: The effect of aqueous acetic acid solution concentration during the preparation of chitosan-acetate (CS-acetate) films on the conductivity and relaxation properties were studied by dielectric and FTIR spectroscopies, TGA measurements and X-Ray diffraction. Analyses of the experimental results on the degree of deacetylation, water absorption, conductivity, Vogel temperature and activation energy demonstrate a strong dependence of these parameters on the concentration of the acid acetic solutions from which the films have been obtained. The proton conductivity and relaxation properties of CS-acetate films have been interpreted using two Grotthuss “structural diffusion” and “pack-acid” mechanisms. The transformation between these two mechanisms observed at temperature higher than CS-acetate glass transition temperature is due to an increase in the thermal motion of CS chains, water evaporation, hydrogen bond between water molecules and side groups of CS breaking and formation of new bonds between NH 3 + and acetate ions. Additionally, application of the Rice and Roth model allowed estimating the temperature dependence of proton number and their mobility in CS-acetate films. A systematic interpretation on the appropriate conductivity mechanism will help trigger the design of smart materials used in flexible electronic, solid polymer electrolytes for fuel cells and solid polymer batteries based on CS-acetate films.

  1. Method for calibrating olfactometer output. Part 2. Amyl acetate.

    Science.gov (United States)

    Maiolo, K C; Walker, J C; Ogden, M W

    2000-07-01

    A method for measuring amyl acetate in air was developed and validated. Known volumes of air samples from the output of an olfactometer, a device used to generate odor stimuli, were passed through charcoal sorbent tubes. Following extraction of the sorbent with carbon disulfide, the amount of amyl acetate collected on each tube was determined by gas chromatography with flame ionization detection. The method was used to determine the actual concentrations of amyl acetate presented to experimental participants in odor sensitivity testing.

  2. Leuprorelin Acetate in Prostate Cancer: a European Update

    OpenAIRE

    Persad R

    2002-01-01

    This review provides an update on leuprorelin acetate, the world's most widely prescribed depot luteinising hormone-releasing hormone analogue. Leuprorelin acetate has been in clinical use in the palliative treatment of prostate cancer for more than 20 years, but advances continue to be made in terms of convenience and flexibility of administration, and in the incorporation of leuprorelin acetate into novel treatment regimens. The drug is administered in the form of a depot injection containi...

  3. Impact of hydrothermalism on the ocean iron cycle.

    Science.gov (United States)

    Tagliabue, Alessandro; Resing, Joseph

    2016-11-28

    As the iron supplied from hydrothermalism is ultimately ventilated in the iron-limited Southern Ocean, it plays an important role in the ocean biological carbon pump. We deploy a set of focused sensitivity experiments with a state of the art global model of the ocean to examine the processes that regulate the lifetime of hydrothermal iron and the role of different ridge systems in governing the hydrothermal impact on the Southern Ocean biological carbon pump. Using GEOTRACES section data, we find that stabilization of hydrothermal iron is important in some, but not all regions. The impact on the Southern Ocean biological carbon pump is dominated by poorly explored southern ridge systems, highlighting the need for future exploration in this region. We find inter-basin differences in the isopycnal layer onto which hydrothermal Fe is supplied between the Atlantic and Pacific basins, which when combined with the inter-basin contrasts in oxidation kinetics suggests a muted influence of Atlantic ridges on the Southern Ocean biological carbon pump. Ultimately, we present a range of processes, operating at distinct scales, that must be better constrained to improve our understanding of how hydrothermalism affects the ocean cycling of iron and carbon.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2016 The Author(s).

  4. Biosphere in 3.5 Ga submarine hydrothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Yuichiro [Tokyo Univ. (Japan). Dept. of Earth Science and Astronomy

    2003-04-01

    Abundant organic matter (kerogen) was identified in {approx}3.5 Ga hydrothermal silica dikes from the North Pole area in the Pilbara craton, Western Australia. The silica dikes developed in the uppermost 1000 m of the ancient oceanic crust. Thus, they would have been deposited in the 3.5 Ga sub-seafloor hydrothermal system. The carbon and nitrogen isotopic compositions of the kerogen were analyzed in this study. Their highly {sup 13}C-depleted isotopic compositions ({delta}{sup 13}C = -38 to -33 per mille) strongly suggest that they are originally derived from biologically produced organic matter. The remarkable similarity of the {delta}{sup 13}C values between the kerogen and modern hydrothermal vent organisms may suggest that the kerogen was derived from chemoautotrophic organisms. This idea is also consistent with their nitrogen isotopic compositions ({delta}{sup 15}N = -4 to +4 per mille). The silica dikes consist mainly of fine-grained silica with minor pyrite and sphalerite. These mineral assemblages indicate that the silica dike was deposited from relatively low-temperature (probably less than 150degC) reducing hydrothermal fluid. Thus, anaerobic thermophilic/hyperthermophilic organisms could have survived in the hydrothermal fluid, which formed the silica dikes. Therefore, it is plausible that a chemoautotrophic-based biosphere (possibly methanogenesis) probably existed in the Early Archean sub-seafloor hydrothermal system. (author)

  5. Molybdenum isotope behaviour in groundwaters and terrestrial hydrothermal systems, Iceland

    Science.gov (United States)

    Neely, Rebecca A.; Gislason, Sigurdur R.; Ólafsson, Magnus; McCoy-West, Alex J.; Pearce, Christopher R.; Burton, Kevin W.

    2018-03-01

    Molybdenum (Mo) isotopes have proved useful in the reconstruction of paleoredox conditions. Their application generally relies upon a simplified model of ocean inputs in which rivers dominate Mo fluxes to the oceans and hydrothermal fluids are considered to be a minor contribution. To date, however, little attention has been paid to the extent of Mo isotope variation of hydrothermal waters, or to the potential effect of direct groundwater discharge to the oceans. Here we present Mo isotope data for two Icelandic groundwater systems (Mývatn and Þeistareykir) that are both influenced by hydrothermal processes. Relative to NIST 3134 = +0.25‰, the cold (Icelandic rivers. In contrast, waters that are hydrothermally influenced (>10 °C) possess isotopically heavy δ98/95MoHYDROTHERMAL values of +0.25‰ to +2.06‰ (n = 18) with the possibility that the high temperature endmembers are even heavier. Although the mechanisms driving this fractionation remain unresolved, the incongruent dissolution of the host basalt and both the dissolution and precipitation of sulfides are considered. Regardless of the processes driving these variations, the δ98Mo data presented in this study indicate that groundwater and hydrothermal waters have the potential to modify ocean budget calculations.

  6. Spontaneous pregnancy during ulipristal acetate treatment of giant uterine leiomyoma.

    Science.gov (United States)

    Hrgovic, Z; Habek, D; Cerkez Habek, J; Hrgovic, I; Jerkovic Gulin, S; Gulin, D

    2018-02-01

    Ulipristal acetate, a progesterone receptor modulator, pharmacologically inhibits endometrial proliferation and thereby prevents pregnancy. It is primarily used as emergency contraception, but also for the treatment of fibroids in women of reproductive age. There have been no published cases of pregnancy, while on therapy with ulipristal acetate. In this article, we present a case report of spontaneous pregnancy during ulipristal acetate therapy. To our knowledge, this is the first patient with spontaneous conception, while on ulipristal acetate treatment. There were no drug-related complications, and the pregnancy resulted in the delivery of a healthy baby. © 2017 John Wiley & Sons Ltd.

  7. Omics analysis of acetic acid tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Geng, Peng; Zhang, Liang; Shi, Gui Yang

    2017-05-01

    Acetic acid is an inhibitor in industrial processes such as wine making and bioethanol production from cellulosic hydrolysate. It causes energy depletion, inhibition of metabolic enzyme activity, growth arrest and ethanol productivity losses in Saccharomyces cerevisiae. Therefore, understanding the mechanisms of the yeast responses to acetic acid stress is essential for improving acetic acid tolerance and ethanol production. Although 329 genes associated with acetic acid tolerance have been identified in the Saccharomyces genome and included in the database ( http://www.yeastgenome.org/observable/resistance_to_acetic_acid/overview ), the cellular mechanistic responses to acetic acid remain unclear in this organism. Post-genomic approaches such as transcriptomics, proteomics, metabolomics and chemogenomics are being applied to yeast and are providing insight into the mechanisms and interactions of genes, proteins and other components that together determine complex quantitative phenotypic traits such as acetic acid tolerance. This review focuses on these omics approaches in the response to acetic acid in S. cerevisiae. Additionally, several novel strains with improved acetic acid tolerance have been engineered by modifying key genes, and the application of these strains and recently acquired knowledge to industrial processes is also discussed.

  8. Metal mobilisation in hydrothermal sediments at the TAG Hydrothermal Field (MAR, 26°N)

    Science.gov (United States)

    Dutrieux, A. M.; Lichtschlag, A.; Martins, S.; Barriga, F. J.; Petersen, S.; Murton, B. J.

    2017-12-01

    Metalliferous sediments in the vicinity of hydrothermal systems are enriched in base metals, but few studies have addressed their potential as mineral resources. These metalliferous sediments have been accumulated by different processes and reflect modifications of the primary mineral deposits by: oxidation of the chimney materials, in situ precipitation of low-temperature minerals and mass wasting. To understand the post-formation processes in metalliferous sediments, we investigated sub-seafloor metal mobilisation in different geological environments. This presentation focuses on the TAG Hydrothermal Field (Mid-Atlantic Ridge, 26°N) and explores sediment and pore water compositions using ICP-MS and ICP-OES. We use reactive transport modelling to interpret the degree of metal remobilisation and to identify the most important geochemical reactions in the different sediments. The pore water concentrations measured in sediments above inactive sulphide mounds present constant major elements composition that indicates this environment is dominated by complete exchange with seawater. The sediments, that are mainly composed of hematite and goethite formed during the oxidation of sulphides, have low Cu concentrations (metal concentrations affected by diagenesis and redox-sensitive metals are released at depth (e.g. Mn2+ and Cu2+). The leaching of the primary sulphides (e.g. deprecated grains of chalcopyrite), and metal mobilisation lead to an enrichment of Cu and Zn at shallower depth. Here, some stratigraphic horizons scavenge metallic cations back into solid phases and form Mn-oxide crusts between 30 and 60 cm, in which Cu concentrations also increase. Our results demonstrate that metal mobilisation differs depending on the geological environment and their related accumulation processes, causing the absence of Cu on the top of inactive hydrothermal mounds but enriched in more distal sediment basins.

  9. LIQUID-LIQUID EQUILIBRIA OF THE ACETIC ACID-WATER-MIXED SOLVENT (CYCLOHEXYL ACETATE-CYCLOHEXANOL SYSTEM

    Directory of Open Access Journals (Sweden)

    S. Çehreli

    2002-03-01

    Full Text Available Mixtures of cyclohexyl acetate and cyclohexanol were used as a mixed solvent to study liquid-liquid equilibria (LLE of the acetic acid-water-cyclohexanol-cyclohexyl acetate quaternary system. The solubility diagram and tie-line data were determined at 298±0.20 K and atmospheric pressure, using various compositions of mixed solvent. Reliability of the data was ascertained by making Othmer-Tobias and Hand plots.

  10. LIQUID-LIQUID EQUILIBRIA OF THE ACETIC ACID-WATER-MIXED SOLVENT (CYCLOHEXYL ACETATE-CYCLOHEXANOL) SYSTEM

    OpenAIRE

    Çehreli S.

    2002-01-01

    Mixtures of cyclohexyl acetate and cyclohexanol were used as a mixed solvent to study liquid-liquid equilibria (LLE) of the acetic acid-water-cyclohexanol-cyclohexyl acetate quaternary system. The solubility diagram and tie-line data were determined at 298±0.20 K and atmospheric pressure, using various compositions of mixed solvent. Reliability of the data was ascertained by making Othmer-Tobias and Hand plots.

  11. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena

    2016-06-14

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  12. Emergency Contraception Options: Focus on Ulipristal Acetate

    Directory of Open Access Journals (Sweden)

    Sharon T. Cameron

    2012-01-01

    Full Text Available Ulipristal acetate (UPA is a progesterone receptor modulator that is available for emergency contraception (EC and can be taken up to 120 hours after unprotected intercourse. A meta-analysis of clinical trials comparing UPA with levonorgestrel (LNG for EC, demonstrated that UPA has higher efficacy than LNG. This higher efficacy is supported by biomedical studies that have demonstrated that UPA is a more potent inhibitor of ovulation, being able to delay ovulation in the immediate preovulatory period, when LNG is no longer effective. A recent study that explored risk factors for failure of EC, demonstrated that obese women were at increased risk of EC failure, with either UPA or LNG. However, failure was significantly less amongst women receiving UPA than those receiving LNG. There is growing evidence therefore, that UPA should be the preferred oral method of EC.

  13. DEOXYRIBONUCLEIC ACID HYBRIDS OF ACETIC ACID BACTERIA

    Science.gov (United States)

    De Ley, J.; Friedman, S.

    1964-01-01

    De Ley, J. (State University, Ghent, Belgium), and S. Friedman. Deoxyribonucleic acid hybrids of acetic acid bacteria. J. Bacteriol. 88:937–945. 1964.—Deuterated N15-labeled deoxyribonucleic acid (DNA) from Acetobacter aceti (mesoxydans 4) forms hybrids with ordinary DNA from other species of this genus (A. xylinum, A. pasteurianus, A. estunensis, and possibly A. xylinoides) when the guanine plus cytosine base composition does not vary by more than 1 to 2%. Beyond this limit (A. aceti Ch31 and A. muciparus 5) no hybrids are formed. The hybrids are apparently derived from an asymmetrical part of the compositional distribution. The results lend strength to the concept of a genetic species rather than to a division of a genus into sharply separated species, based on small phenotypic differences. Taxonomic implications are discussed. PMID:14219057

  14. Ulipristal acetate as an emergency contraceptive agent.

    Science.gov (United States)

    Martinez, Alan M; Thomas, Michael A

    2012-09-01

    Emergency contraceptive agents play a crucial role in preventing unplanned pregnancy. These agents and devices have been studied since the 1960s and have had varied results in terms of side effects and efficacy. A new oral tablet for emergency contraception (EC), ulipristal acetate (UPA) , is a selective progesterone receptor modulator and can be used up to 120 h following unprotected intercourse, without an increase in adverse effects or a decrease in efficacy. This article reviews studies that evaluate the pharmacodynamics, pharmacokinetics, clinical efficacy, and safety profile of UPA as an emergency contraceptive agent. UPA, a selective progesterone receptor modulator, is administered as a single 30 mg dose for EC. This agent provides a comparable, if not better, efficacy and side effect profile than seen with levonorgestrel or mifepristone. Because it has both agonistic and antagonistic effects on the progesterone receptor, ongoing clinical trials are documenting UPA's use for patients with endometriosis and as an extended use contraceptive.

  15. Ulipristal acetate: a new emergency contraceptive.

    Science.gov (United States)

    Sullivan, Jade L; Bulloch, Marilyn N

    2011-07-01

    Ulipristal acetate (UPA) is a newly developed emergency contraceptive currently available in the USA and Europe. It is approved as a 30 mg one-time dose taken within 120 h (5 days) of unprotected intercourse or failed contraception. This selective progesterone receptor modulator appears to be more effective than the levonorgestrel-containing emergency contraceptive, which must be taken within 72 h of unprotected intercourse. According to pharmacodynamic trials, UPA delays follicular maturation and ovulation. In addition, UPA may modulate the endometrium. Both Phase III clinical trials found that UPA does not lose efficacy within the 120-h dosing interval. Throughout all phases of clinical studies, UPA was shown to be well tolerated with only minimal adverse drug reactions, all of which are similar to competitor therapies.

  16. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  17. Light at deep sea hydrothermal vents

    Science.gov (United States)

    Van Dover, Cindy Lee; Cann, J. R.; Cavanaugh, Colleen; Chamberlain, Steven; Delaney, John R.; Janecky, David; Imhoff, Johannes; Tyson, J. Anthony

    We usually think of the bottom of the sea as a dark environment, lit only by flashes of bioluminescent light. Discovery of light associated with geothermal processes at deep sea hydrothermal vents forces us to qualify our textbook descriptions of the seafloor as a uniformly dark environment. While a very dim glow emitted from high temperature (350°) vents (black smokers) at mid-oceanic ridge spreading centers has been documented [Van Dover et al, 1988], the source of this light and its role, if any, in the evolution and adaptation of photobiochemical processes have yet to be determined. Preliminary studies indicate that thermal radiation alone may account for the “glow” ]Smith and Delaney, 1989] and that a novel photoreceptor in shrimp-colonizing black smoker chimneys may detect this “glow” [Van Dover et al., 1989; Pelli and Chamberlain, 1989]. A more controversial question, posed by C. L. Van Dover, J. R. Cann, and J. R. Delaney at the 1993 LITE Workshop at the Woods Hole Oceanographic Institution in Massachusetts, is whether there may be sufficient light of appropriate wavelengths to support geothermally driven photosynthesis by microorganisms.

  18. Hydrothermal Gasification for Waste to Energy

    Science.gov (United States)

    Epps, Brenden; Laser, Mark; Choo, Yeunun

    2014-11-01

    Hydrothermal gasification is a promising technology for harvesting energy from waste streams. Applications range from straightforward waste-to-energy conversion (e.g. municipal waste processing, industrial waste processing), to water purification (e.g. oil spill cleanup, wastewater treatment), to biofuel energy systems (e.g. using algae as feedstock). Products of the gasification process are electricity, bottled syngas (H2 + CO), sequestered CO2, clean water, and inorganic solids; further chemical reactions can be used to create biofuels such as ethanol and biodiesel. We present a comparison of gasification system architectures, focusing on efficiency and economic performance metrics. Various system architectures are modeled computationally, using a model developed by the coauthors. The physical model tracks the mass of each chemical species, as well as energy conversions and transfers throughout the gasification process. The generic system model includes the feedstock, gasification reactor, heat recovery system, pressure reducing mechanical expanders, and electricity generation system. Sensitivity analysis of system performance to various process parameters is presented. A discussion of the key technological barriers and necessary innovations is also presented.

  19. Hydrothermal Liquefaction Treatment Hazard Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, Peter P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wagner, Katie A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-12

    Hazard analyses were performed to evaluate the modular hydrothermal liquefaction treatment system. The hazard assessment process was performed in 2 stages. An initial assessment utilizing Hazard Identification and Preliminary Hazards Analysis (PHA) techniques identified areas with significant or unique hazards (process safety-related hazards) that fall outside of the normal operating envelope of PNNL and warranted additional analysis. The subsequent assessment was based on a qualitative What-If analysis. The analysis was augmented, as necessary, by additional quantitative analysis for scenarios involving a release of hazardous material or energy with the potential for affecting the public. The following selected hazardous scenarios received increased attention: •Scenarios involving a release of hazardous material or energy, controls were identified in the What-If analysis table that prevent the occurrence or mitigate the effects of the release. •Scenarios with significant consequences that could impact personnel outside the immediate operations area, quantitative analyses were performed to determine the potential magnitude of the scenario. The set of “critical controls” were identified for these scenarios (see Section 4) which prevent the occurrence or mitigate the effects of the release of events with significant consequences.

  20. Hydrothermal evolution of repository groundwaters in basalt

    International Nuclear Information System (INIS)

    Apps, J.A.

    1984-01-01

    Groundwaters in the near field of a radioactive waste repository in basalt will change their chemical composition in response to reactions with the basalt. These reactions will be promoted by the heat generated by the decaying waste. It is important to predict both the rate and the extent of these reactions, and the secondary minerals produced, because the alteration process controls the chemical environment affecting the corrosion of the canister, the solubility and complexation of migrating radionuclides, the reactivity of the alteration products to radionuclides sorption, and the porosity and permeability of the host rock. A comprehensive review of the literature leads to the preliminary finding that hydrothermally altering basalts in geothermal regions such as Iceland lead to a secondary mineralogy and groundwater composition similar to that expected to surround a repository. Furthermore, laboratory experiments replicating the alteration conditions approximate those observed in the field and expected in a repository. Preliminary estimates were made of the rate of hydration and devitrification of basaltic glass and the zero-order dissolution rate of basaltic materials. The rates were compared with those for rhyolitic glasses and silicate minerals. Preliminary calculations made of mixed process alteration kinetics, involving pore diffusion and surface reaction suggest that at temperatures greater than 150 0 C, alteration proceeds so rapidly as to become pervasive in normally fractured basalt exposed to higher temperatures in the field. 70 references

  1. Reconnaissance of the hydrothermal resources of Utah

    Energy Technology Data Exchange (ETDEWEB)

    Rush, F.E.

    1983-01-01

    Geologic factors in the Basin and Range province in Utah are more favorable for the occurrence of geothermal resources than in other areas on the Colorado Plateaus or in the Middle Rocky Mountains. These geologic factors are principally crustal extension and crustal thinning during the last 17 million years. Basalts as young as 10,000 years have been mapped in the area. High-silica volcanic and intrusive rocks of Quaternary age can be used to locate hydrothermal convection systems. Drilling for hot, high-silica, buried rock bodies is most promising in the areas of recent volcanic activity. Southwestern Utah has more geothermal potential than other parts of the Basin and Range province in Utah. The Roosevelt Hot Springs area, the Cove Fort-Sulphurdale area, and the area to the north as far as 60 kilometers from them probably have the best potential for geothermal development for generation of electricity. Other areas with estimated reservoir temperatures greater than 150/sup 0/C are Thermo, Monroe, Red Hill (in the Monroe-Joseph Known Geothermal Resource Area), Joseph Hot Springs, and the Newcastle area. The rates of heat and water discharge are high at Crater, Meadow, and Hatton Hot Springs, but estimated reservoir temperatures there are less than 150/sup 0/C. Additional exploration is needed to define the potential in three additional areas in the Escalante Desert. 28 figs., 18 tabs.

  2. The behaviour of tungsten electrodes in a mixture of acetic acid and acetic anhydride

    International Nuclear Information System (INIS)

    Pastor, T.J.; Vajgand, V.H.

    1976-01-01

    Tungsten electrodes have advantageously been used for potentiometric end-point detection in perchloric acid titration of bases in a mixture of acetic acid and acetic anhydride. They have also given good results in biamperometric detection of the equivalence point in continuous coulometric titration of small quantities of bases and acids in the same solvent. Tungsten electrodes in the presence of quinhydrone behave like platinum electrodes, but in biamperometric end-point determination in the absence of quinhydrone it is better to remove the oxide layer from their surface. Some other factors affecting their behaviour have also been studied. Errors in determination do not exceed +-2% even in titration of very small quantities of substances. (author)

  3. Liquid-Liquid equilibria of the water-acetic acid-butyl acetate system

    Directory of Open Access Journals (Sweden)

    Ince E.

    2002-01-01

    Full Text Available Experimental liquid-liquid equilibria of the water-acetic acid-butyl acetate system were studied at temperatures of 298.15± 0.20, 303.15± 0.20 and 308.15± 0.20 K. Complete phase diagrams were obtained by determining solubility and tie-line data. The reliability of the experimental tie-line data was ascertained by using the Othmer and Tobias correlation. The UNIFAC group contribution method was used to predict the observed ternary liquid-liquid equilibrium (LLE data. It was found that UNIFAC group interaction parameters used for LLE did not provide a good prediction. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  4. Kinetic Modelling and Experimental Study of Small Esters: Methyl Acetate and Ethyl Acetate

    KAUST Repository

    Ahmed, Ahfaz

    2017-12-14

    A detailed chemical kinetic mechanism comprising methyl acetate and ethyl acetate has been developed based on the previous work by Westbrook et al. [1]. The newly developed kinetic mechanism has been updated with new reaction rates from recent theoretical studies. To validate this model, shock tube experiments measuring ignition delay time have been conducted at 15 & 30 bar and equivalence ratio 0.5, 1.0 and 2.0. Another set of experiments measuring laminar burning velocity was also performed on a heat flux burner at atmospheric pressure over wide range of equivalence ratios [~0.7-1.4]. The new mechanism shows significant improvement in prediction of experimental data over earlier model across the range of experiments.

  5. Anaerobic digestion of post-hydrothermal liquefaction wastewater for improved energy efficiency of hydrothermal bioenergy processes.

    Science.gov (United States)

    Zhou, Yan; Schideman, Lance; Zheng, Mingxia; Martin-Ryals, Ana; Li, Peng; Tommaso, Giovana; Zhang, Yuanhui

    2015-01-01

    Hydrothermal liquefaction (HTL) is a promising process for converting wet biomass and organic wastes into bio-crude oil. It also produces an aqueous product referred to as post-hydrothermal liquefaction wastewater (PHWW) containing up to 40% of the original feedstock carbon, which reduces the overall energy efficiency of the HTL process. This study investigated the feasibility of using anaerobic digestion (AD) to treat PHWW, with the aid of activated carbon. Results showed that successful AD occurred at relatively low concentrations of PHWW (≤ 6.7%), producing a biogas yield of 0.5 ml/mg CODremoved, and ∼53% energy recovery efficiency. Higher concentrations of PHWW (≥13.3%) had an inhibitory effect on the AD process, as indicated by delayed, slower, or no biogas production. Activated carbon was shown to effectively mitigate this inhibitory effect by enhancing biogas production and allowing digestion to proceed at higher PHWW concentrations (up to 33.3%), likely due to sequestering toxic organic compounds. The addition of activated carbon also increased the net energy recovery efficiency of AD with a relatively high concentration of PHWW (33.3%), taking into account the energy for producing activated carbon. These results suggest that AD is a feasible approach to treat PHWW, and to improve the energy efficiency of the HTL processes.

  6. Emerging diversity of hydrothermal systems on slow spreading ocean ridges

    Science.gov (United States)

    Rona, Peter A.

    The development of seafloor hydrothermal research has followed a classic scientific progression in which discoveries were initially interpreted as special cases until further exploration revealed their more general significance. The first high-temperature seafloor hydrothermal system was found at the Atlantis II Deep of the slow spreading Red Sea in 1963. At that time, the hydrothermal activity was largely discounted as an anomaly associated with continental rifting rather than as part of an early stage of opening of an ocean basin that could continue with the development of ocean ridges as in the Atlantic. When high-temperature black smoker hydrothermal venting was found on the East Pacific Rise in 1979, the scientific consensus then held that the relatively high rate of magma supply at intermediate to fast spreading rates was required for such activity. Accordingly, high-temperature hydrothermal activity could not occur on the slow spreading half of the global ocean ridge system. High-temperature black smokers like those on the East Pacific Rise were first discovered on a slow spreading ocean ridge at the TAG hydrothermal field on the Mid-Atlantic Ridge in 1985. The scientific consensus then ruled out the possibility for such activity on the ultraslow portion of the ocean ridge system. Plumes indicative of active high-temperature black smokers were found on the ultraslow spreading Gakkel Ridge in the Arctic in 2001, and active black smokers were found on the Southwest Indian Ridge in 2006. A diversity of high-temperature hydrothermal systems remains to be found on ocean ridges, particularly at slow spreading rates.

  7. Sulfur Isotope Geochemistry of Mariana Arc Hydrothermal Systems

    Science.gov (United States)

    Miyabe, S.; Butterfield, D. A.; Roe, K. K.; Ishibashi, J.; Embley, R. W.; Chiba, H.; Nakamura, K.

    2004-12-01

    Sulfur isotope measurments were performed on H2S and SO4 in hydrothermal fluids together with elemental sulfur precipitates collected from newly discovered active hydrothermal systems in Mariana Arc. These samples were collected during R/V Thomas G Thompson cruise with ROPOS at March 2004, conducted under Submarine Ring of Fire 2004 project. We report sulfur isotope systematics of these hydrothermal fluids comparing with those from TOTO cauldron in southern Mariana Arc previously studied. The venting fluids from some Mariana Arc hydrothermal systems have remarkably low \\delta 34S(H2S) values (-5.9 to -10.0\\permil for NW Rota, -3.0 to -6.9\\permil for NW Eifuku, -5.5\\permil for Kasuga 2) as well as TOTO ( -3.8\\permil). Compared with mid-oceanic ridge hydrothermal fluids showing \\delta 34S of -2.3 to + 7.3\\permil, these low values suggests that the Mariana Arc and TOTO caldera hydrothermal systems are distinctive in terms of production mechanisms of hydrogen sulfide or source of sulfur. At NW Rota Pit, we found that, venting fluid has higher sulfate concentration (35.4mM) and slightly lower\\delta 34S value (19.0\\permil) than ambient seawater (28mM, 21.0\\permil). We also confirmed existence of sulfur spherules (\\delta 34S =-5.1\\permil). These results suggest disproportionation reaction of the exsolved SO2 from a magma body is a predominant mechanism of sulfur species of the hydrothermal system. Extremely low pH of the fluid agrees with production of sulfuric acid by disproportionation.

  8. The potential hydrothermal systems unexplored in the Southwest Indian Ocean

    Science.gov (United States)

    Suo, Yanhui; Li, Sanzhong; Li, Xiyao; Zhang, Zhen; Ding, Dong

    2017-06-01

    Deep-sea hydrothermal vents possess complex ecosystems and abundant metallic mineral deposits valuable to human being. On-axial vents along tectonic plate boundaries have achieved prominent results and obtained huge resources, while nearly 90% of the global mid-ocean ridge and the majority of the off-axial vents buried by thick oceanic sediments within plates remain as relatively undiscovered domains. Based on previous detailed investigations, hydrothermal vents have been mapped along five sections along the Southwest Indian Ridge (SWIR) with different bathymetry, spreading rates, and gravity features, two at the western end (10°-16°E Section B and 16°-25°E Section C) and three at the eastern end (49°-52°E Section D, 52°-61°E Section E and 61°-70°E Section F). Hydrothermal vents along the Sections B, C, E and F with thin oceanic crust are hosted by ultramafic rocks under tectonic-controlled magmatic-starved settings, and hydrothermal vents along the Section D are associated with exceed magmatism. Limited coverage of investigations is provided along the 35°-47°E SWIR (between Marion and Indomed fracture zones) and a lot of research has been done around the Bouvet Island, while no hydrothermal vents has been reported. Analyzing bathymetry, gravity and geochemical data, magmatism settings are favourable for the occurrence of hydrothermal systems along these two sections. An off-axial hydrothermal system in the southern flank of the SWIR that exhibits ultra-thin oceanic crust associated with an oceanic continental transition is postulated to exist along the 100-Ma slow-spreading isochron in the Enderby Basin. A discrete, denser enriched or less depleted mantle beneath the Antarctic Plate is an alternative explanation for the large scale thin oceanic crust concentrated on the southern flank of the SWIR.

  9. Bioelectrochemical Ethanol Production through Mediated Acetate Reduction by Mixed Cultures

    NARCIS (Netherlands)

    Steinbusch, K.J.J.; Hamelers, H.V.M.; Schaap, J.D.; Kampman, C.; Buisman, C.J.N.

    2010-01-01

    Biological acetate reduction with hydrogen is a potential method to convert wet biomass waste into ethanol. Since the ethanol concentration and reaction rates are low, this research studies the feasibility of using an electrode, in stead of hydrogen, as an electron donor for biological acetate

  10. Effects of culture conditions on acetic acid production by bacteria ...

    African Journals Online (AJOL)

    SARAH

    2015-11-30

    Nov 30, 2015 ... implicated in conversion of ethanol into acetic acid. (Tayama et al., 1989). Therefore, incapacity of these strains to produce acetic acid at 45 °C is probably due to several factors unexplained in our knowledge especially since Moghadami et al. (2013) have demonstrated that thermotolerant strains have high.

  11. Fermentation characteristics of Fusarium oxysporum grown on acetate

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Pachidou, Fotini; Petroutsos, Dimitris

    2008-01-01

    TCA cycle intermediates when F. oxysporum cells were grown on mixtures of acetate and glucose compared to growth on only glucose. Our data support the hypothesis that it higher flux through TCA cycle during acetate consumption could significantly increase the pool of NADH, resulting in the activation...

  12. Modelling and Simulation of the Batch Hydrolysis of Acetic ...

    African Journals Online (AJOL)

    The kinetic modelling of the batch synthesis of acetic acid from acetic anhydride was investigated. The kinetic data of the reaction was obtained by conducting the hydrolysis reaction in a batch reactor. A dynamic model was formulated for this process and simulation was carried out using gPROMS® an advanced process ...

  13. Development of Chitosan Acetate Films for Transdermal Delivery of ...

    African Journals Online (AJOL)

    Methods: Chitosan acetate was chemically modified with acetaldehyde and the solution was prepared with 1 % acetic acid, in which was dissolved propranolol hydrochloride, was cast as films in Petri dish and characterised by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and ...

  14. Effect of antimicrobial agents on cellulose acetate nano composites properties

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Francisco J.; Bruna, Julio E.; Galotto, Maria J.; Guarda, Abel; Sepulveda, Hugo, E-mail: francisco.rodriguez.m@usach.cl [Center for the Development of Nanoscience and Nanotechnology (CEDENNA). Universidad de Santiago de Chile. Faculty of Technology. Department of Food Science and Technology. Food Packaging Laboratory. Santiago (Chile)

    2011-07-01

    Nano composites based on cellulose acetate, Cloisite 30B, triethyl citrate and thymol or cinnamaldehyde were prepared using a dissolution casting technique. The effect of thymol and cinnamaldehyde on the cellulose acetate nano composite properties was evaluated by XRD and DSC. Important changes on the thermal properties and morphological structure were observed according to thymol and cinnamaldehyde content. (author)

  15. Ethyl acetate production by the elusive alcohol acetyltransferase from yeast

    NARCIS (Netherlands)

    Kruis, Alex; Levisson, Mark; Mars, Astrid E.; Ploeg, van der Max; Garcés Daza, Fernando; Ellena, Valeria; Kengen, Servé W.M.; Oost, van der John; Weusthuis, Ruud A.

    2017-01-01

    Ethyl acetate is an industrially relevant ester that is currently produced exclusively through unsustainable processes. Many yeasts are able to produce ethyl acetate, but the main responsible enzyme has remained elusive, hampering the engineering of novel production strains. Here we describe the

  16. Antimicrobial activity of ethyl acetate extract of Citrullus lanatus seeds

    African Journals Online (AJOL)

    Purpose: To determine the antimicrobial activity and chemical constituents of ethyl acetate extract of Citrullus lanatus seeds. Methods: Antimicrobial activity of the ethyl acetate extract of the seeds of C. lanatus was evaluated against Staphylococus aureus ATCC 25923, Escherichia coli ATCC 25922, Bacillus subtilis ...

  17. Antibacterial activity of various fractions of ethyl acetate extract from ...

    African Journals Online (AJOL)

    The antibacterial activity of various fractions of ethyl acetate extract isolated from edible fungi, Tirmania pinoyi (Maire) Malençon, growing in Algeria, was investigated. Extraction was done by the Soxhlet and the fractions obtained were purified with silica-gel column. Two fractions of ethyl acetate extract were tested against ...

  18. Controlled free radical polymerization of vinyl acetate with cobalt ...

    Indian Academy of Sciences (India)

    C, the colour-free reaction without solid catalyst impurity was 95% complete within a few hours. The high molecular weight of polyvinyl acetate (PVAc) with its relatively low molecular distribution without unreacted monomer provided a new method in microprocessing of the controlled radical polymerization of vinyl acetate in ...

  19. Antimycobacterial activity of two natural alkaloids, vasicine acetate ...

    Indian Academy of Sciences (India)

    MADHU

    natural compounds, vasicine acetate and 2-acetyl benzylamine, were isolated from it. They were ... [Ignacimuthu S and Shanmugam N 2010 Antimycobacterial activity of two natural alkaloids, vasicine acetate and 2-acetyl benzylamine, isolated from Indian shrub ..... of natural products for antimycobacterial activity by using.

  20. Acetalization of furfural with zeolites under benign reaction conditions

    DEFF Research Database (Denmark)

    Rubio-Caballeroa, Juan Miguel; Shunmugavel, Saravanamurugan; Maireles-Torres, Pedro

    2014-01-01

    to form furfuraldiethyl acetal at room temperature using ethanol as a renewable solvent. Among the tested catalysts,H-USY (6) provided the highest catalytic activity (79% acetal yield), excellent selectivity and reusabilityin five consecutive reaction runs. Process parameters such as, e.g. reaction time...

  1. Effect of antimicrobial agents on cellulose acetate nano composites properties

    International Nuclear Information System (INIS)

    Rodriguez, Francisco J.; Bruna, Julio E.; Galotto, Maria J.; Guarda, Abel; Sepulveda, Hugo

    2011-01-01

    Nano composites based on cellulose acetate, Cloisite 30B, triethyl citrate and thymol or cinnamaldehyde were prepared using a dissolution casting technique. The effect of thymol and cinnamaldehyde on the cellulose acetate nano composite properties was evaluated by XRD and DSC. Important changes on the thermal properties and morphological structure were observed according to thymol and cinnamaldehyde content. (author)

  2. Microbial acetate oxidation in horizontal rotating tubular bioreactor

    Indian Academy of Sciences (India)

    The microbial culture was not only grown in a suspension but also in the form of a biofilm on the interior surface of HRTB. Efficiency of the bioprocess was monitored by determination of the acetate concentration and chemical oxygen demand (COD). While acetate inlet concentration and feeding rate influenced efficiency of ...

  3. Antimicrobial activity of ethyl acetate extract of Citrullus lanatus seeds

    African Journals Online (AJOL)

    Purpose: To determine the antimicrobial activity and chemical constituents of ethyl acetate extract of. Citrullus lanatus seeds. Methods: Antimicrobial activity of the ethyl acetate extract of the seeds of C. lanatus was evaluated against Staphylococus aureus ATCC 25923, Escherichia coli ATCC 25922, Bacillus subtilis ...

  4. Samarium (III) acetate-chloride hydrates: dimers and chains

    International Nuclear Information System (INIS)

    Meyer, G.; Lossin, A.; Schleid, T.

    1991-01-01

    Except for samarium chloride and samarium acetate, the system Sm 3+ /Ac - /Cl - /H 2 0 contains two acetate-chloride hydrates, [SmAc(H 2 0) 6 ]Cl 2 . H 2 0 (1) and [SmAc 2 (H 2 0) 3 ]Cl (2). Single crystals of 1 are obtained from an aqueous acetic-acid solution of SmCl 3 .6H 2 0 by slow isothermal evaporation at room temperature, those of 2 analogously but from a solution of SmOCl. 1 crystallizes with the triclinic system and contains centro-symmetric dimers with nine-coordinate Sm 3+ (six aquo ligands and one tridentate bridging acetate anion). 2 crystallizes with the monoclinic system with one-dimensional infinite chains, and Sm 3+ again in a ninefold oxygen coordination (three aquo and two tridentate bridging acetate ligands)

  5. Antimicrobial activity of Butyl acetate, Ethyl acetate and Isopropyl alcohol on undesirable microorganisms in cosmetic products.

    Science.gov (United States)

    Lens, C; Malet, G; Cupferman, S

    2016-10-01

    The microbiological contamination risk of a cosmetic product has to be assessed by the manufacturer, according to the composition, to determine whether microbiological testing is required. Certain ingredients in cosmetic formulations help to create an environment hostile towards microbial growth. In this study, the influence on microbial survival of some solvents used in nail varnishes was evaluated. The purpose of this study was two-fold. The first was to define the thresholds to be considered for the exemption of products from microbiological testing. The second was to assess the cross-contamination risk linked to the use on successive consumers of solvent-based products in beauty salons. Strains of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans and Trichophyton rubrum were exposed to various concentrations of ethyl acetate, butyl acetate and isopropyl alcohol in culture medium to estimate their MIC (minimum inhibitory concentration). These strains are relevant to cosmetic products as they are associated with skin and nail infections. Mixtures of the three solvents, which are characteristic of nail varnish compositions, were also tested for their cidal activity. Ethyl and butyl acetates had a stronger impact than isopropyl alcohol: the MIC of ethyl and butyl acetate is ≤5% for all of the tested strains, whereas that of isopropyl alcohol is ≤10%. Various combinations of the three solvents tested showed a significant effect on both fungal and bacterial strains (greater than 3 log reduction in 15 min for the bacterial test strains and in 30 min for T. rubrum). Products containing more than 5% ethyl or butyl acetate or more than 10% isopropyl alcohol are hostile towards microbial growth. These products can therefore be considered as microbiologically low risk during both production and use, and so do not require microbiological testing (challenge test and end-product testing). Moreover, the nine tested mixtures of these three

  6. Phreatic and Hydrothermal Explosions: A Laboratory Approach

    Science.gov (United States)

    Scheu, B.; Dingwell, D. B.

    2010-12-01

    Phreatic eruptions are amongst the most common eruption types on earth. They might be precursory to another type of volcanic eruption but often they stand on their one. Despite being the most common eruption type, they also are one of the most diverse eruptions, in appearance as well as on eruption mechanism. Yet steam is the common fuel behind all phreatic eruptions. The steam-driven explosions occur when water beneath the ground or on the surface is heated by magma, lava, hot rocks, or fresh volcanic deposits (such as ignimbrites, tephra and pyroclastic-flow deposits) and result in crater, tuff rings and debris avalanches. The intense heat of such material may cause water to boil and flash to steam, thereby generating an explosion of steam, water, ash, blocks, and bombs. Another wide and important field affected by phreatic explosions are hydrothermal areas; here phreatic explosions occur every few months creating explosion craters and resemble a significant hazard to hydrothermal power plants. Despite of their hazard potential, phreatic explosions have so far been overlooked by the field of experimental volcanology. A part of their hazard potential in owned by the fact that phreatic explosions are hardly predictable in occurrence time and size as they have manifold triggers (variances in groundwater and heat systems, earthquakes, material fatigue, water level, etc..) A new set of experiments has been designed to focus on this phreatic type of steam explosion, whereas classical phreatomagmatic experiments use molten fuel-coolant interaction (e.g., Zimanowski, et al., 1991). The violent transition of the superheated water to vapour adds another degree of explosivity to the dry magmatic fragmentation, driven mostly by vesicle bursting due to internal gas overpressure. At low water fractions the fragmentation is strongly enforced by the mixture of these two effects and a large fraction of fine pyroclasts are produced, whereas at high water fraction in the sample the

  7. Delineation of myocardial oxygen utilization with carbon-11-labeled acetate

    International Nuclear Information System (INIS)

    Brown, M.; Marshall, D.R.; Sobel, B.E.; Bergmann, S.R.

    1987-01-01

    Although positron-emission tomography (PET) with labeled fatty acid delineates infarct size and permits qualitative assessment of fatty acid utilization, quantification of oxidative metabolism is limited by complex alterations in the pattern of utilization of fatty acid during ischemia and reperfusion. Because metabolism of acetate by myocardium is less complex than that of glucose or palmitate, we characterized kinetics of utilization of radiolabeled acetate in 37 isolated rabbit hearts perfused with modified Krebs-Henseleit buffer and performed a pilot tomographic study in man. Results of initial experiments with carbon-14-labeled acetate ( 14 C-acetate) indicated that the steady-state extraction fraction of acetate averaged 61.5 +/- 4.0% in control hearts (n = 4), 93.6 +/- 0.9% in hearts rendered ischemic (n = 4), and 54.8 +/- 4.0% in hearts reperfused after 60 min of ischemia (n = 3). Oxidation of 14 C-acetate, assessed from the rate of efflux of 14 CO 2 in the venous effluent, correlated closely with the rate of oxygen consumption under diverse metabolic conditions (r = .97, p less than .001). In addition, no significant differences were observed between rates of efflux of total 14 C in all chemical species (reflecting total clearance of tracer from myocardium) and efflux of 14 CO 2 . Clearance of 11 C-acetate, measured externally with gamma probes in normal and ischemic myocardium, correlated closely with clearance of 14 C-acetate measured directly in the effluent (r = .99, p less than .001) and with overall myocardial oxygen consumption (r = .95, p less than .001). Accumulation and clearance of 11 C-acetate from human myocardium with PET demonstrated kinetics comparable to those seen with radiolabeled acetate in vitro

  8. Hydrothermally Synthesized Zinc Sulphide Microspheres for Solar Light-Driven Photocatalytic Properties

    Science.gov (United States)

    Waghadkar, Yogesh; Arbuj, Sudhir; Shinde, Manish; Ballal, Reshma; Rane, Sunit B.; Gosavi, Suresh; Fouad, H.; Chauhan, Ratna

    2018-02-01

    In this work, we reported the synthesis of zinc sulphide microspheres using the hydrothermal method. ZnS microspheres were synthesized using water, zinc acetate, thiourea and ammonia solution at 150°C for 6 h, 12 h, and 24 h. The as-synthesized ZnS powders were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-Vis) spectroscopy. XRD indicates the cubic (major phase) as well as hexagonal (minor phase) crystalline phase with enhanced crystallinity increased gradually with more reaction time. UV-Vis spectra show the absorption peaks in the UV-Vis region for all the samples. The Tauc's plot was used to calculate the band gap energy of ZnS samples, which are found to be 3.39 eV, 3.4 eV, and 3.42 eV for the samples synthesized at reaction times of 6 h, 12 h, and 24 h, respectively. FESEM images confirm the formation of microspheres as aggregates of spherical nanoparticles. The as-synthesized ZnS microspheres have been explored for solar light-induced photo-catalytic dye degradation of methylene blue (MB), and the results confirm that such microspheres exhibit effectual photocatalytic properties.

  9. The Geological Setting of Hydrothermal Vent Sites on Gakkel Ridge

    Science.gov (United States)

    Edwards, M. H.; Edmonds, H. N.; Johnson, P. D.

    2006-12-01

    In 1998 and 1999, the Science Ice Exercises (SCICEX) mapped the fine-scale textures of the flanks and axial valley of Gakkel Ridge, the slowest-spreading mid-ocean ridge on Earth (full-spreading rates 250 teleseismic events that occurred in 1999 [Müller and Jokat, 1999; Edwards et al., 2001]. During the 2001 Arctic Mid-Ocean Ridge Expedition (AMORE), hydrothermal plume reconnaissance conducted during rock sampling operations revealed evidence of abundant hydrothermal venting on the Gakkel Ridge [Edmonds et al., 2003]. Comparison of the plume distributions with multibeam bathymetry data collected during AMORE showed that vent plumes were closely associated with topographic highs located inside the axial valley, with the largest and highest-temperature plume coinciding with the 85°E volcano. We describe the geological setting of vent plumes discussed in Edmonds et al. [2003] by integrating water column information from the AMORE program with detailed textural data from the SCICEX surveys and develop predictions for locations where hydrothermal venting is likely to occur on ultra-slow spreading mid-ocean ridges. Our efforts focus on five hydrothermal sites identified by Edmonds et al. [2003] and Baker et al. [2004] (7.5°E, 37°°E, 43°E, 55°E and 85°E). We co-register the observed plume distributions with interpretative maps showing the locations of tectonic and volcanic features such as faults and reflective lava flows in order to characterize the hydrothermal sites. These results are compared with similar interpretative products for the 69°E region and other sites where plume signals were observed but the hydrothermal activity could not be localized based on the strength of the hydrothermal signals or the occurrence of "near-field" signatures such as distinct layering or temperature anomalies. Finally, we examine reflective regions not associated with plumes, either because no hydrothermal anomalies were detected or the regions were not hydrographically

  10. Bacterial Diets of Primary Consumers at Hydrothermal Vents

    Science.gov (United States)

    Govenar, B.; Shank, T. M.

    2008-12-01

    Chemical energy produced by mixing hydrothermal fluids and seawater supports dense biological communities on mid-ocean ridges. The base of the food web at deep-sea hydrothermal vents is formed by chemolithoautotrophic bacteria that use the energy from the oxidation of reduced chemicals to fix inorganic carbon into simple sugars. With the exception of a few species that have chemolithoautotropic bacterial symbionts, most of the vent-endemic macrofauna are heterotrophs that feed on free-living bacteria, protists, and other invertebrates. The most abundant and diverse group of primary consumers in hydrothermal vent communities belong to the Gastropoda, particularly the patellomorph limpets. Gastropod densities can be as high as 2000 individuals m-2, and there can be as many as 13 species of gastropods in a single aggregation of the siboglinid tubeworm Riftia pachyptila and more than 40 species along the East Pacific Rise. Some gastropods are ubiquitous and others are found in specific microhabitats, stages of succession, or associated with different foundation species. To determine the mechanisms of species coexistence (e.g. resource partitioning or competition) among hydrothermal vent primary consumers and to track the flow of energy in hydrothermal vent communities, we employed molecular genetic techniques to identify the gut contents of four species of co-occurring hydrothermal vent gastropods, Eulepetopsis vitrea, Lepetodrilus elevatus, Lepetodrilus ovalis and Lepetodrilus pustulosus, collected from a single diffuse-flow hydrothermal vent site on the East Pacific Rise. Unique haplotypes of the 16S gene that fell among the epsilon-proteobacteria were found in the guts of every species, and two species had gut contents that were similar only to epsilon-proteobacteria. Two species had gut contents that also included haplotypes that clustered with delta-proteobacteria, and one species had gut contents that clustered with alpha- proteobacteria. Differences in the diets

  11. Effects of process parameters on hydrothermal carbonization

    Science.gov (United States)

    Uddin, Md. Helal

    In recent years there has been increased research activity in renewable energy, especially upgrading widely available lignicellulosic biomass, in a bid to counter the increasing environmental concerns related with the use of fossil fuels. Hydrothermal carbonization (HTC), also known as wet torrefaction or hot water pretreatment, is a process for pretreatment of diverse lignocellulosic biomass feedstocks, where biomass is treated under subcritical water conditions in short contact time to produce high-value products. The products of this process are: a solid mass characterized as biochar/biocoal/biocarbon, which is homogeneous, energy dense, and hydrophobic; a liquid stream composed of five and six carbon sugars, various organic acids, and 5-HMF; and a gaseous stream, mainly CO2. A number of process parameters are considered important for the extensive application of the HTC process. Primarily, reaction temperature determines the characteristics of the products. In the solid product, the oxygen carbon ratio decreases with increasing reaction temperature and as a result, HTC biochar has the similar characteristics to low rank coal. However, liquid and gaseous stream compositions are largely correlated with the residence time. Biomass particle size can also limit the reaction kinetics due to the mass transfer effect. Recycling of process water can help to minimize the utility consumption and reduce the waste treatment cost as a result of less environmental impact. Loblolly pine was treated in hot compressed water at 200 °C, 230 °C, and 260 °C with 5:1 water:biomass mass ratio to investigate the effects of process parameters on HTC. The solid product were characterized by their mass yields, higher heating values (HHV), and equilibrium moisture content (EMC), while the liquid were characterized by their total organic carbon content and pH value.

  12. Silver nanoparticles in combination with acetic acid and zinc oxide quantum dots for antibacterial activities improvement-A comparative study

    Science.gov (United States)

    Sedira, Sofiane; Ayachi, Ahmed Abdelhakim; Lakehal, Sihem; Fateh, Merouane; Achour, Slimane

    2014-08-01

    Due to their remarkable antibacterial/antivirus properties, silver nanoparticles (Ag NPs) and zinc oxide quantum dots (ZnO Qds) have been widely used in the antimicrobial field. The mechanism of action of Ag NPs on bacteria was recently studied and it has been proven that Ag NPs exerts their antibacterial activities mainly by the released Ag+. In this work, Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method, respectively. It was demonstrated that Ag NPs can be oxidized easily in aqueous solution and the addition of acetic acid can increase the Ag+ release which improves the antibacterial activity of Ag NPs. A comparative study between bactericidal effect of Ag NPs/acetic acid and Ag NPs/ZnO Qds on Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus was undertaken using agar diffusion method. The obtained colloids were characterized using UV-vis spectroscopy, Raman spectrometry, X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM).

  13. Structural Evolution of Molybdenum Carbides in Hot Aqueous Environments and Impact on Low-Temperature Hydroprocessing of Acetic Acid

    Directory of Open Access Journals (Sweden)

    Jae-Soon Choi

    2015-03-01

    Full Text Available We investigated the structural evolution of molybdenum carbides subjected to hot aqueous environments and their catalytic performance in low-temperature hydroprocessing of acetic acid. While bulk structures of Mo carbides were maintained after aging in hot liquid water, a portion of carbidic Mo sites were converted to oxidic sites. Water aging also induced changes to the non-carbidic carbon deposited during carbide synthesis and increased surface roughness, which in turn affected carbide pore volume and surface area. The extent of these structural changes was sensitive to the initial carbide structure and was lower under actual hydroprocessing conditions indicating the possibility of further improving the hydrothermal stability of Mo carbides by optimizing catalyst structure and operating conditions. Mo carbides were active in acetic acid conversion in the presence of liquid water, their activity being comparable to that of Ru/C. The results suggest that effective and inexpensive bio-oil hydroprocessing catalysts could be designed based on Mo carbides, although a more detailed understanding of the structure-performance relationships is needed, especially in upgrading of more complex reaction mixtures or real bio-oils.

  14. The origin of methanethiol in midocean ridge hydrothermal fluids

    Science.gov (United States)

    Reeves, Eoghan P.; McDermott, Jill M.; Seewald, Jeffrey S.

    2014-01-01

    Simple alkyl thiols such as methanethiol (CH3SH) are widely speculated to form in seafloor hot spring fluids. Putative CH3SH synthesis by abiotic (nonbiological) reduction of inorganic carbon (CO2 or CO) has been invoked as an initiation reaction for the emergence of protometabolism and microbial life in primordial hydrothermal settings. Thiols are also presumptive ligands for hydrothermal trace metals and potential fuels for associated microbial communities. In an effort to constrain sources and sinks of CH3SH in seafloor hydrothermal systems, we determined for the first time its abundance in diverse hydrothermal fluids emanating from ultramafic, mafic, and sediment-covered midocean ridge settings. Our data demonstrate that the distribution of CH3SH is inconsistent with metastable equilibrium with inorganic carbon, indicating that production by abiotic carbon reduction is more limited than previously proposed. CH3SH concentrations are uniformly low (∼10−8 M) in high-temperature fluids (>200 °C) from all unsedimented systems and, in many cases, suggestive of metastable equilibrium with CH4 instead. Associated low-temperature fluids (fluids, resembling our observations from a sediment-hosted system. This strongly implicates thermogenic interactions between upwelling fluids and microbial biomass or associated dissolved organic matter during subsurface mixing in crustal aquifers. Widespread thermal degradation of subsurface organic matter may be an important source of organic production in unsedimented hydrothermal systems and may influence microbial metabolic strategies in cooler near-seafloor and plume habitats. PMID:24706901

  15. The hydrothermal exploration system on the 'Qianlong2' AUV

    Science.gov (United States)

    Tao, W.; Tao, C.; Jinhui, Z.; Cai, L.; Guoyin, Z.

    2016-12-01

    ABSTRACT: Qianlong2, is a fully Autonomous Underwater Vehicle (AUV) designed for submarine resources research, especially for polymetallic sulphides, and the survey depths of is up to 4500 m. Qianlong2 had successfully explored hydrothermal vent field on the Southwest Indian Ridge (SWIR), and collected conductance, temperature and depth (CTD), turbidity, and Oxidation-Reduction Potential (ORP) data. It also had mapped precise topography by high resolution side scan sonar (HRBSSS) during every dive; and obtained photographs of sulfide deposits during some dives. Here, we detailedly described the implementation of investigation, data administration, and fast mapping of hydrothermal exploration system by Qianlong2. Giving a description of how to remove the platform magnetic interference by using magnetic data during Qianlong2 spin. Based on comprehensive hydrochemical anomalies, we get a rapid method for finding the localization of hydrothermal vents. Taking one dive as an example, we systemically showed the process about how to analyse hydrothermal survey data and acquire the location results of hydrothermal vents. Considering that this method is effective and can be used in other deep-submergence assets such as human occupied vehicles (HOVs) and remotely operated vehicles (ROVs) during further studies. Finally, we discussed how to promote and optimize the installation and application of those sensors and how to improve Qianlong2's autonomy of investigation.

  16. Duration of hydrothermal treatment and peeling of 'Murcott' tangor

    Directory of Open Access Journals (Sweden)

    Ana Luiza Pinheiro

    2011-12-01

    Full Text Available Hydrothermal treatment facilitates the peeling of 'Pera' sweet orange fruit and does not alter its quality. The aim of this work was to adapt the technology of peeling for the use of hydrothermal treatment in 'Murcott' tangor and to evaluate its influence in the CO2 production and the physicochemical, microbiologic and sensorial characteristics of fruits. The peeling time, the yield of marketable fruits and the internal temperature of fruits during the treatment were also evaluated. The hydrothermal treatment consisted of placing the fruits in a water-bath at 50 ºC for 5, 10, 15, 20, 25 and 30 min. Fruits were peeled by first opening a gap in the peduncle region with a knife and then manually removing the flavedo and albedo. Fruits were stored at 5 ºC for six days. Hydrothermal treatment caused changes in the fruits' CO2 production for only the first few hours after processing. Internal fruit temperature after 30 min of treatment reached 35 ºC. There were no changes in the physicochemical and microbiologic characteristics of the fruits. The treatment did not change the flavor, improved the fruits' appearance, decreased the peeling time of the treated fruits by 57 % and increased the yield of marketable fruits. In conclusion, the hydrothermal treatment accomplished from 5 to 30 min at 50 ºC can be used as part of the peeling process for 'Murcott' tangor.

  17. Hydrothermal influence on nearshore sediments of Kos Island, Aegean Sea

    Science.gov (United States)

    Megalovasilis, Pavlos; Godelitsas, Athanasios

    2015-04-01

    The Kos-Nisyros volcanic centre is a long-active, Plio-Pleistocene magmatic system in the subduction zone along the easternmost edge of the active Hellenic volcanic arc in the Aegean Sea. Although today there are signs of relative quiescence in volcanic activity, active onshore fumaroles and shallow-sea hydrothermal vents persist on, amongst others, the island of Kos. The present study explores the large-scale imprint of hydrothermally sourced heavy metals and nutrients on the island's coastal marine environment, based on geochemical data collected in September 2007 from hydrothermal waters and surficial nearshore sediments (measurement period on 15-16 September 2007. Confirming earlier work, hydrothermal waters had higher levels of F, Ca and Sr, and lower levels of Na, Mg and SO4 compared with ambient seawater. Moreover, there was novel evidence of strong, widespread Zn and also Mn enhancement. Cluster and factor analyses of surficial sediment data from the Bros Thermi vents (fine (mud) fractions, metallic sulphide deposits of hydrothermal origin at depth beneath Kos.

  18. Metallogenesis of rich uranium deposits in Xiangshan hydrothermal ore field

    International Nuclear Information System (INIS)

    Wen Zhijian; Du Letian; Liu Zhengyi

    2001-01-01

    Xiangshan Uranium Ore field located in Jiangxi Province, south of China, is one of the largest volcanogenic hydrothermal uranium ore fields in China. There are apparent difference in uranium metallogenesis between low-grade deposits and rich uranium ones (U > 0.3%, especially U > 1%) in Xiangshan hydrothermal uranium ore field. The special hydrothermal solution with higher content of P, Ti, K elements is a geochemical controlling factor for rich uranium mineralization. Fluorine is an important transporter for uranium migration in hydrothermal system, however, it plays a limited function of uranium mineralization. In fact, uranium and thorium are migrated and precipitated through some complicated processes including alkali-metasomatism, co-migration, colloid co-precipitation with phosphate minerals and gas reduction etc., which has been proved by field investigation, experiments and a number of analysis. The deeper the orebodies are located, the higher the grade of ore is. The reasonable explanation is as following: (1) the contents of P, Ti, F, K. U and reducing gases in hydrothermal solution increase along with deepness; (2) The temperature and pressure in deep are higher than that on shallower parts. All the factors mentioned above together play active roles in uranium enrichment. Some suggestions for further exploitation and exploration in Xiangshan area have been put forward

  19. Evidence for Hesperian Impact-Induced Hydrothermalism on Mars

    Science.gov (United States)

    Marzo, Giuseppe A.; Davila, Alfonso F.; Tornabene, Livio L.; Dohm, James M.; Fairen, Alberto G.; Gross, Christoph; Kneissl, Thomas; Bishop, Janice L.; Roush, Ted L.; McKay, Chris P.

    2010-01-01

    Several hydrated silicate deposits on Mars are observed within craters and are interpreted as excavated Noachian material. Toro crater (71.8 deg E, 17.0 deg N), located on the northern edge of the Syrtis Major Volcanic Plains, shows spectral and morphologic evidence of impact-induced hydrothermal activity. Spectroscopic observations were used to identify extensive hydrated silicate deposits, including prehnite, chlorites, smectites, and opaline material, a suite of phases that frequently results from hydrothermal alteration in terrestrial craters and also expected on Mars from geochemical modeling of hydrothermal environments. When combined with altimetry and high-resolution imaging data, these deposits appear associated predominantly with the central uplift and with portions of the northern part of the crater floor. Detailed geologic mapping of these deposits reveals geomorphic features that are consistent with hydrothermal activity that followed the impact event, including vent-like and conical mound structures, and a complex network of tectonic structures caused by fluid interactions such as fractures and joints. The crater age has been calculated from the cumulative crater size-frequency distributions and is found to be Early Hesperian. The evidence presented here provides support for impact-induced hydrothermal activity in Toro crater, that extends phyllosilicate formation processes beyond the Noachian era.

  20. Impact-generated Hydrothermal Activity at the Chicxulub Crater

    Science.gov (United States)

    Kring, D. A.; Zurcher, L.; Abramov, O.

    2007-05-01

    Borehole samples recovered from PEMEX exploration boreholes and an ICDP scientific borehole indicate the Chicxulub impact event generated hydrothermal alteration throughout a large volume of the Maya Block beneath the crater floor and extending across the bulk of the ~180 km diameter crater. The first indications of hydrothermal alteration were observed in the crater discovery samples from the Yucatan-6 borehole and manifest itself in the form of anhydrite and quartz veins. Continuous core from the Yaxcopoil-1 borehole reveal a more complex and temporally extensive alteration sequence: following a brief period at high temperatures, impact- melt-bearing polymict breccias and a thin, underlying unit of impact melt were subjected to metasomatism, producing alkali feldspar, sphene, apatite, and magnetite. As the system continued to cool, smectite-series phyllosilicates appeared. A saline solution was involved. Stable isotopes suggest the fluid was dominated by a basinal brine created mostly from existing groundwater of the Yucatan Peninsula, although contributions from down-welling water also occurred in some parts of the system. Numerical modeling of the hydrothermal system suggests circulation occurred for 1.5 to 2.3 Myr, depending on the permeability of the system. Our understanding of the hydrothermal system, however, is still crude. Additional core recovery projects, particularly into the central melt sheet, are needed to better evaluate the extent and duration of hydrothermal alteration.

  1. The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses

    Directory of Open Access Journals (Sweden)

    Lindinger Michael I

    2007-12-01

    Full Text Available Abstract Aim Sodium acetate (NaAcetate has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial; or 2 a hay/grain meal alone (Control trial. Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse.

  2. Biological Function of Acetic Acid-Improvement in Obesity and Glucose Tolerance by Acetic Acid in Type 2 Diabetic Rats.

    Science.gov (United States)

    Yamashita, Hiromi

    2016-07-29

    Fatty acids derived from adipose tissue are oxidized by β-oxidation to form ketone bodies as final products under the starving condition. Previously, we found that free acetic acid was formed concomitantly with the production of ketone bodies in isolated rat liver perfusion, and mitochondrial acetyl CoA hydrolase was appeared to be involved with the acetic acid production. It was revealed that acetic acid was formed as a final product of enhanced β-oxidation of fatty acids and utilized as a fuel in extrahepatic tissues under the starving condition. Under the fed condition, β-oxidation is suppressed and acetic acid production is decreased. When acetic acid was taken daily by obesity-linked type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats under the fed condition, it protected OLETF rats against obesity. Furthermore, acetic acid contributed to protect from the accumulation of lipid in the liver as well as abdominal fat in OLETF rats. Transcripts of lipogenic genes in the liver were decreased, while transcripts of myoglobin and Glut4 genes in abdominal muscles were increased in the acetic acid-administered OLETF rats. It is indicated that exogenously administered acetic acid would have effects on lipid metabolism in both the liver and the skeletal muscles, and have function that works against obesity and obesity-linked type 2 diabetes.

  3. Microsomal metabolism of trenbolone acetate metabolites ...

    Science.gov (United States)

    Trenbolone acetate (TBA) is a synthetic growth promoter widely used in animal agriculture, and its metabolites are suspected endocrine disrupting compounds in agriculturally impacted receiving waters. However, beyond the three widely recognized TBA metabolites (17-trenbolone, 17-trenbolone and trendione), little is known about other metabolites formed in vivo and subsequently discharged into the environment, with some evidence suggesting these unknown metabolites comprise a majority of the TBA mass dosed to the animal. Here, we explored the metabolism of the three known TBA metabolites using rat liver microsome studies. All TBA metabolites are transformed into a complex mixture of monohydroxylated products. Based on product characterization, the majority are more polar than the parent metabolites but maintain their characteristic trienone backbone. A minor degree of interconversion between known metabolites was also observed, as were higher order hydroxylated products with a greater extent of reaction. Notably, the distribution and yield of products were generally comparable across a series of variably induced rat liver microsomes, as well as during additional studies with human and bovine liver microsomes. Bioassays conducted with mixtures of these transformation products suggest that androgen receptor (AR) binding activity is diminished as a result of the microsomal treatment, suggesting that the transformation products are generally less potent than

  4. Effect of Acetate Group Content in Ethylene-Vinyl Acetate Copolymer on Properties of Composite Based on Low Density Polyethylene and Polyamide-6

    OpenAIRE

    Nhi Dinh Bui; Ngo Dinh Vu; Thao Thi Minh; Huong Thi Thanh Dam; Regina Romanovna Spiridonova; Semenovich Alexandr Sirotkin

    2016-01-01

    The effect of the content of vinyl acetate groups in ethylene-vinyl acetate copolymer on the properties of polymer composite based on low density polyethylene and polyamide-6 was studied. Ethylene-vinyl acetate copolymer containing less vinyl acetate groups (10–14 wt.%) has a positive compatibility effect on polymer composite than ethylene-vinyl acetate copolymer containing 21–30 wt.% vinyl acetate groups. The polymer composites of LDPE, PA-6, and EVA containing 10–14 wt.% vinyl acetate group...

  5. Vapour pressures and vapour-liquid equilibria of propyl acetate and isobutyl acetate with ethanol or 2-propanol at 0.15 MPa. Binary systems

    Directory of Open Access Journals (Sweden)

    Susial Pedro

    2012-01-01

    Full Text Available Vapour pressures of propyl acetate, isobutyl acetate and 2-propanol from 0.004 to 1.6 MPa absolute pressure and VLE data for the binary systems propyl acetate+ethanol, propyl acetate+2-propanol, isobutyl acetate+ethanol and isobutyl acetate+2-propanol at 0.15 MPa have been determined. The experimental VLE data were verified with the test of van Ness and the Fredenslund criterion. The propyl acetate+ethanol or +2-propanol binary systems have an azeotropic point at 0.15 MPa. The different versions of the UNIFAC and ASOG group contribution models were applied.

  6. Application of cultural algorithm to generation scheduling of hydrothermal systems

    International Nuclear Information System (INIS)

    Yuan Xiaohui; Yuan Yanbin

    2006-01-01

    The daily generation scheduling of hydrothermal power systems plays an important role in the operation of electric power systems for economics and security, which is a large scale dynamic non-linear constrained optimization problem. It is difficult to solve using traditional optimization methods. This paper proposes a new cultural algorithm to solve the optimal daily generation scheduling of hydrothermal power systems. The approach takes the water transport delay time between connected reservoirs into consideration and can conveniently deal with the complicated hydraulic coupling simultaneously. An example is used to verify the correctness and effectiveness of the proposed cultural algorithm, comparing with both the Lagrange method and the genetic algorithm method. The simulation results demonstrate that the proposed algorithm has rapid convergence speed and higher solution precision. Thus, an effective method is provided to solve the optimal daily generation scheduling of hydrothermal systems

  7. Process characteristics for microwave assisted hydrothermal carbonization of cellulose.

    Science.gov (United States)

    Zhang, Junting; An, Ying; Borrion, Aiduan; He, Wenzhi; Wang, Nan; Chen, Yirong; Li, Guangming

    2018-07-01

    The process characteristics of microwave assisted hydrothermal carbonization of cellulose was investigated and a first order kinetics model based on carbon concentration was developed. Chemical properties analysis showed that comparing to conventional hydrothermal carbonization, hydrochar with comparable energy properties can be obtained with 5-10 times decrease in reaction time with assistance of microwave heating. Results from kinetics study was in great agreement with experimental analysis, that they both illustrated the predominant mechanism of the reaction depend on variations in the reaction rates of two co-existent pathways. Particularly, the pyrolysis-like intramolecular dehydration reaction was proved to be the predominant mechanism for hydrochar generation under high temperatures. Finally, the enhancement effects of microwave heating were reflected under both soluble and solid pathways in this research, suggesting microwave-assisted hydrothermal carbonization as a more attracting method for carbon-enriched hydrochar recovery. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Hydrothermal metallurgy for recycling of slag and glass

    International Nuclear Information System (INIS)

    Tanaka, Toshihiro; Yoshikawa, Takeshi; Hirai, Nobumitsu; Katsuyama, Shigeru

    2009-01-01

    The authors have applied hydrothermal reactions to develop recycling processing of slag or glass. As an example, under hydrothermal conditions such as 200 300 deg. C and 30 40MPa with H 2 O, powders made of glass can be sintered to become solidified glass materials containing about 10mass% H 2 O. When the glass containing H 2 O is heated again under normal pressure, the glass expands releasing H 2 O to make porous microstructure. H 2 O starts to emit just above the glass transition temperature. Therefore, when we have a glass with low glass transition temperature, we can make low temperature foaming glass. The SiO 2 -Na 2 O-B 2 O 3 glass is a candidate to be such a foaming glass. In this paper, we describe our recent trial on the fabrication of the low temperature foaming glass by using hydrothermal reaction.

  9. Fractionation of Boron Isotopes in Icelandic Hydrothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, J.K.; Palmer, M.R.

    1995-01-01

    Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive {delta}{sup 11}B than the high temperature systems, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems.

  10. Study on hydrothermal synthesis dynamics of nanoscale xonotlite fibers

    Science.gov (United States)

    Liu, F.; Chen, S.; Lin, Q.; Wang, X. D.; Cao, J. X.

    2018-01-01

    The xonotlite crystals were synthesized via the hydrothermal synthesis manner from CaO and SiO2 as the raw materials with their Si/Ca molar ratio of 1.0. Hydrothermal synthesis dynamics of nanoscale xonotlite fibers was explored by masterly measuring the electrical conductivities and the calcium concentrations of product slurries synthesized at various reaction temperature in this paper. The results indicated that the calculated values of the products’ quality at various reaction temperatures were consistent with the measured values. Based on chemical reaction kinetic, using fourth-order Runge-Kutta method, spline interpolation and least-squares fitting method, the dynamic relationship of xonotlite fibers synthesized via hydrothermal synthesis process is of -{dc}A/{dt}={kc}A4/5.

  11. Chemical reaction path modeling of hydrothermal processes on Mars: Preliminary results

    Science.gov (United States)

    Plumlee, Geoffrey S.; Ridley, W. Ian

    1992-01-01

    Hydrothermal processes are thought to have had significant roles in the development of surficial mineralogies and morphological features on Mars. For example, a significant proportion of the Martian soil could consist of the erosional products of hydrothermally altered impact melt sheets. In this model, impact-driven, vapor-dominated hydrothermal systems hydrothermally altered the surrounding rocks and transported volatiles such as S and Cl to the surface. Further support for impact-driven hydrothermal alteration on Mars was provided by studies of the Ries crater, Germany, where suevite deposits were extensively altered to montmorillonite clays by inferred low-temperature (100-130 C) hydrothermal fluids. It was also suggested that surface outflow from both impact-driven and volcano-driven hydrothermal systems could generate the valley networks, thereby eliminating the need for an early warm wet climate. We use computer-driven chemical reaction path calculation to model chemical processes which were likely associated with postulated Martian hydrothermal systems.

  12. Perspectives for the biotechnological production of ethyl acetate by yeasts.

    Science.gov (United States)

    Löser, Christian; Urit, Thanet; Bley, Thomas

    2014-06-01

    Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester.

  13. Exploration Method Development for hydrothermal plume hunting by XCTD

    Science.gov (United States)

    Kitagawa, Y.; Ikeda, M.; Kadoshima, K.; Koizumi, Y.; Nakano, J.; Asakawa, E.; Sumi, T.

    2017-12-01

    J-MARES (Research and Development Partnership for Next Generation Technology of Marine Resources Survey, JAPAN) has been designing a low-cost and high-efficiency exploration system for seafloor hydrothermal massive sulfide deposits in "Cross-ministerial Strategic Innovation Promotion Program (SIP)" granted by the Cabinet Office, Government of Japan since 2014. We proposed hydrothermal plume hunting by XCTD (eXpendables Conductivity, Temperature and Depth). We applied this method to an area of interest more than 100km x 100km over Okinawa Trough, including some known seafloor massive sulfide deposits. Generally, hydrothermal plume exploration has been by ship mounted with MBES (Multi Beam Echo Sounder) or AUV with sound anomaly observation. However, these methods have to charter the sophisticated ship costly. On the other hand, throw-in type water quality meters (eg. XCTD and XBT) can be low-cost and easily operable. Moreover, that can make a quick look at seawater temperature and conductivity even in rough waters.Firstly, we confirmed XCTD probes position on the seafloor by ROV mounted deep-sea high vision camera. As a result of the test, probes swept downstream about 40 m in horizontal distance from throwing positions with about 1,600m in water depth. Following the previous test results, we had performed to the next test that confirmed detection range of hydrothermal plume at the chimney of North Mound in Izena Cauldron, so we had caught anomaly of seawater temperature and conductivity successfully which could be possibly derived from hydrothermal activities. Although averaged seawater temperature at a depth of 1500 m or more was about 3.95 degrees C, near the chimney was about 4.93 degrees C. The temperature anomalies originated from the hydrothermal plumes could be distributed at most 30m in horizontal distance and became smaller away from the chimney. Moreover, temperature anomaly mass of sea water tended to move upward in depth with distance away from the

  14. Coastal submarine hydrothermal activity off northern Baja California

    International Nuclear Information System (INIS)

    Vidal, V.M.V.; Vidal, F.V.; Isaacs, J.D.; Young, D.R.

    1978-01-01

    In situ observations of submarine hydrothermal activity have been conducted in Punta Banda. Baja Califronia, Mexico, approximately 400 m from the coast and at a seawater depth of 30 m. The hydrothermal activity occurs within the Agua Blanca Fault, a major transverse structure of Northern Baja California. Hot springwater samples have been collected and analyzed. Marked differences exist between the submarine hot springwater, local land hot springwaters, groundwater, and local seawater. SiO 2 , HCO 3 , Ca, K, Li, B, Ba, Rb, Fe, Mn, As, and Zn are enriched in the submarine hot springwater, while Cl, Na, So 4 2 , Mg, Cu, Ni, Cd, Cr, and perhaps Pb are depleted in relation to average and local seawater values. Very high temperatures, at the hydrothermal vents, have been recorded (102 0 C at 4-atm pressure). Visible gaseous emanations rich in CH 4 and N 2 coexist with the hydrothermal solutions. Metalliferous deposits, pyrite, have been encountered with high concentrations of Fe, S, Si, Al, Mn, Ca, and the volatile elements As, Hg, Sb, and Tl, X ray dispersive spectrometry (1500-ppm detection limit). X ray diffraction, and scanning electron microscopy of the isolated metalliferous precipitates indicate that the principal products of precipitation are pyrite and gypsum accompanied by minor amounts of amorphous material containing Si and Al. Chemical analyses and XRD of the reference control rocks of the locality (volcanics) versus the hydrothermally altered rocks indicate that high-temperature and high-pressure water-rock interactions can in part explain the water chemistry characteristics of the submarine hydrothermal waters. Their long residence time, the occurrence of an extensive marine sedimentary formation, their association with CH 4 and their similarities with connate waters of oil and gas fields suggest that another component of their genesis could be in cation exchange reactions within deeply buried sediments of marine origin

  15. Electrochemistry of Prebiotic Early Earth Hydrothermal Chimney Systems

    Science.gov (United States)

    Hermis, N.; Barge, L. M.; Chin, K. B.; LeBlanc, G.; Cameron, R.

    2017-12-01

    Hydrothermal chimneys are self-organizing chemical garden precipitates generated from geochemical disequilibria within sea-vent environments, and have been proposed as a possible setting for the emergence of life because they contain mineral catalysts and transect ambient pH / Eh / chemical gradients [1]. We simulated the growth of hydrothermal chimneys in early Earth vent systems by using different hydrothermal simulants such as sodium sulfide (optionally doped with organic molecules) which were injected into an early Earth ocean simulant containing dissolved ferrous iron, nickel, and bicarbonate [2]. Chimneys on the early Earth would have constituted flow-through reactors, likely containing Fe/Ni-sulfide catalysts that could have driven proto-metabolic electrochemical reactions. The electrochemical activity of the chimney system was characterized non-invasively by placing electrodes at different locations across the chimney wall and in the ocean to analyze the bulk properties of surface charge potential in the chimney / ocean / hydrothermal fluid system. We performed in-situ characterization of the chimney using electrochemical impedance spectroscopy (EIS) which allowed us to observe the changes in physio-chemical behavior of the system through electrical spectra of capacitance and impedance over a wide range of frequencies during the metal sulfide chimney growth. The electrochemical properties of hydrothermal chimneys in natural systems persist due to the disequilibria maintained between the ocean and hydrothermal fluid. When the injection in our experiment (analogous to fluid flow in a vent) stopped, we observed a corresponding decline in open circuit voltage across the chimney wall, though the impedance of the precipitate remained lor. Further work is needed to characterize the electrochemistry of simulated chimney systems by controlling response factors such as electrode geometry and environmental conditions, in order to simulate electrochemical reactions

  16. Dynamic behavior of Kilauea Volcano and its relation to hydrothermal systems and geothermal energy

    Science.gov (United States)

    Kauhikaua, Jim; Moore, R.B.; ,

    1993-01-01

    Exploitation of hydrothermal systems on active basaltic volcanoes poses some unique questions about the role of volcanism and hydrothermal system evolution. Volcanic activity creates and maintains hydrothermal systems while earthquakes create permeable fractures that, at least temporarily, enhance circulation. Magma and water, possibly hydrothermal water, can interact violently to produce explosive eruptions. Finally, we speculate on whether volcanic behavior can be affected by high rates of heat extraction.

  17. Integrated analysis of hydrothermal flow through pretreatment

    Directory of Open Access Journals (Sweden)

    Archambault-Leger Veronique

    2012-07-01

    Full Text Available Abstract Background The impact of hydrothermal flowthrough (FT pretreatment severity on pretreatment and solubilization performance metrics was evaluated for three milled feedstocks (corn stover, bagasse, and poplar and two conversion systems (simultaneous saccharification and fermentation using yeast and fungal cellulase, and fermentation by Clostridium thermocellum. Results Compared to batch pretreatment, FT pretreatment consistently resulted in higher XMG recovery, higher removal of non-carbohydrate carbon and higher glucan solubilization by simultaneous saccharification and fermentation (SSF. XMG recovery was above 90% for FT pretreatment below 4.1 severity but decreased at higher severities, particularly for bagasse. Removal of non-carbohydrate carbon during FT pretreatment increased from 65% at low severity to 80% at high severity for corn stover, and from 40% to 70% for bagasse and poplar. Solids obtained by FT pretreatment were amenable to high conversion for all of the feedstocks and conversion systems examined. The optimal time and temperature for FT pretreatment on poplar were found to be 16 min and 210°C. At these conditions, SSF glucan conversion was about 85%, 94% of the XMG was removed, and 62% of the non carbohydrate mass was solubilized. Solubilization of FT-pretreated poplar was compared for C. thermocellum fermentation (10% inoculum, and for yeast-fungal cellulase SSF (5% inoculum, cellulase loading of 5 and 10 FPU/g glucan supplemented with β-glucosidase at 15 and 30 U/g glucan. Under the conditions tested, which featured low solids concentration, C. thermocellum fermentation achieved faster rates and more complete conversion of FT-pretreated poplar than did SSF. Compared to SSF, solubilization by C. thermocellum was 30% higher after 4 days, and was over twice as fast on ball-milled FT-pretreated poplar. Conclusions XMG removal trends were similar between feedstocks whereas glucan conversion trends were significantly

  18. Fate of Organic Micropollutants during Hydrothermal Carbonization

    Science.gov (United States)

    Weiner, B.; Baskyr, I.; Pörschmann, J.; Kopinke, F.-D.

    2012-04-01

    The hydrothermal carbonization (HTC) is an exothermic process, in which biomass in an aqueous suspension is transformed into a bituminous coal-like material (hydrochar) at temperatures between 180-250°C and under moderate pressure. With these process conditions, little gas is generated (1-5%), and a fraction of the organic carbon is dissolved in the aqueous phase (10-30%) but the largest part is obtained as solid char. The respective yields and the molecular composition depend on the choice of educts and the process conditions, such as temperature, pH-value, and reaction time. Various biomass-educts have recently been studied, such as waste materials from agriculture, brewer's spent grains, sewage sludge, as well as wood and paper materials. Besides their use for energy generation, the hydrochars have also been investigated as soil amendments. Prior to addition of the chars to soil, these should be free of toxic components that could be released into the environment as harmful organic pollutants. Herein, the potential for the degradation of trace organic pollutants, such as pesticides and pharmaceuticals, under typical HTC conditions will be presented. The degradation of selected organic pollutants with different polarity and hydrophobicity was investigated. Scope and limitations of the degradation potential of the HTC are discussed on examples of micro pollutants such as hormones, residues of pharmaceuticals and personal care products including their metabolites, and pesticides. We will show that the target analytes are partially and in some cases completely degraded. The degree of degradation depends on the HTC process conditions such as reaction temperature and time, the solution pH value, the presence of catalysts or additional reagents. The biotic and abiotic degradation of chlorinated organic compounds, in particular chlorinated aromatics, has been a well-known environmental problem and remains a challenging issue for the development of a HTC process for

  19. Hydrothermal plume anomalies over the southwest Indian ridge: magmatic control

    Science.gov (United States)

    Yue, X.; Li, H.; Tao, C.; Ren, J.; Zhou, J.; Chen, J.; Chen, S.; Wang, Y.

    2017-12-01

    Here we firstly reported the extensive survey results of the hydrothermal activity along the ultra-slow spreading southwest Indian ridge (SWIR). The study area is located at segment 27, between the Indomed and Gallieni transform faults, SWIR. The seismic crustal thickness reaches 9.5km in this segment (Li et al., 2015), which is much thicker than normal crustal. The anomaly thickened crust could be affected by the Crozet hotspot or highly focused melt delivery from the mantle. The Duanqiao hydrothermal field was reported at the ridge valley of the segment by Tao et al (2009). The Deep-towed Hydrothermal Detection System (DHDS) was used to collect information related with hydrothermal activity, like temperature, turbidity, oxidation-reduction potential (ORP) and seabed types. There are 15 survey lines at the interval of 2 to 3 km which are occupied about 1300 km2 in segment 27. After processing the raw data, including wiping out random noise points, 5-points moving average processing and subtracting the ambient, we got anomalous Nephelometric Turbidity Units values (ΔNTU). And dE/dt was used to identify the ORP anomalous as the raw data is easily influenced by electrode potentials drifting (Baker et al., 2016). According to the results of water column turbidity and ORP distributions, we confirmed three hydrothermal anomaly fields named A1, A2 and A3. The three fields are all located in the western part of the segment. The A1 field lies on the ridge valley, west side of Duanqiao field. The A2 and A3 field lie on the northern and southern of the ridge valley, respectively. We propose that recent magmatic activity probably focus on the western part of segment 27.And the extensive distribution of hydrothermal plume in the segment is the result of the discrete magma intrusion. References Baker E T, et al. How many vent fields? New estimates of vent field populations on ocean ridges from precise mapping of hydrothermal discharge locations. EPSL, 2016, 449:186-196. Li J

  20. Integration of hydrothermal-energy economics: related quantitative studies

    Energy Technology Data Exchange (ETDEWEB)

    1982-08-01

    A comparison of ten models for computing the cost of hydrothermal energy is presented. This comparison involved a detailed examination of a number of technical and economic parameters of the various quantitative models with the objective of identifying the most important parameters in the context of accurate estimates of cost of hydrothermal energy. Important features of various models, such as focus of study, applications, marked sectors covered, methodology, input data requirements, and output are compared in the document. A detailed sensitivity analysis of all the important engineering and economic parameters is carried out to determine the effect of non-consideration of individual parameters.

  1. Acetate oxidation by bloodstream forms of Trypanosoma cruzi.

    Science.gov (United States)

    Docampo, R; Cruz, F S; Leon, W; Schmunis, G A

    1979-05-01

    Bloodstream forms of Trypanosoma cruzi had a substantial increase in respiration in the presence of acetate. Oxidation of acetate took place via the tricarboxylic acid cycle and involved an antimycin A-sensitive respiratory pathway. Oxygen uptake in the presence of acetate was a sensitive to antimycin A inhibition as was CO2 production. There was a 6--7% residual O2 uptake which was not inhibited by high antimycin concentrations. Human anti-T. cruzi sera had no effect on oxygen uptake.

  2. Study of alkaline-earth element complexes in anhydrous acetic acid

    International Nuclear Information System (INIS)

    Petit, N.

    1968-10-01

    We have studied the complexes of alkaline-earth elements in anhydrous acetic acid. Using glass-electrode potentiometry we have studied the titration of alkaline earth acetates with perchloric acid which is the strongest acid in anhydrous acetic acid. These titrations have shown that the basic strength of these acetates increases as follows: Mg 4 ); the mixed acetate-acid sulfate complex of barium: Ba (OAc)(HSO 4 ); the mixed acetate-chloride of barium: Ba (OAc)(Cl). (author) [fr

  3. Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.

    Science.gov (United States)

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent…

  4. Measurement and correlation of the solubility of gossypol acetic acid and gossypol acetic acid of optical activity in different solvents

    Science.gov (United States)

    Zhang, B.; Tang, H.; Liu, X. Y.; Zhai, X.; Yao, X. C.

    2018-01-01

    The equilibrium method was used to measure the solubility of gossypol acetic acid and gossypol acetic acid of optical activity in isopropyl alcohol, ethanol, acetic acid and ethyl acetate at temperature from 288.15 to 315.15. The Empirical equation and the Apelblat equation model were adopted to correlate the experimental data. For gossypol acetic acid, the root-mean-square deviations (RMSD) were observed in the range of 0.023-4.979 and 0.0112-0.614 for the Empirical equation and the Apelblat equation, respectively. For gossypol acetic acid of optical activity, the RMSD were observed in the range of 0.021-2.211 and 0.021-2.243 for the Empirical equation and the Apelblat equation, individually. And the maximum relative average deviation was 7.5%. Both equations offered an accurate mathematical expression of the experimental results. The calculated solubility showed a good relationship with the experimental solubility for most of solvents. This study provided valuable datas not only for optimizing the process of purification of gossypol acetic acid of optical activity in industry but also for further theoretical studies.

  5. Cosolvent gel-like materials from partially hydrolyzed poly(vinyl acetate)s and borax.

    Science.gov (United States)

    Angelova, Lora V; Terech, Pierre; Natali, Irene; Dei, Luigi; Carretti, Emiliano; Weiss, Richard G

    2011-09-20

    A gel-like, high-viscosity polymeric dispersion (HVPD) based on cross-linked borate, partially hydrolyzed poly(vinyl acetate) (xPVAc, where x is the percent hydrolysis) is described. Unlike hydro-HVPDs prepared from poly(vinyl alcohol) (PVA) and borate, the liquid portion of these materials can be composed of up to 75% of an organic cosolvent because of the influence of residual acetate groups on the polymer backbone. The effects of the degree of hydrolysis, molecular weight, polymer and cross-linker concentrations, and type and amount of organic cosolvent on the rheological and structural properties of the materials are investigated. The stability of the systems is explored through rheological and melting-range studies. (11)B NMR and small-angle neutron scattering (SANS) are used to probe the structure of the dispersions. The addition of an organic liquid to the xPVAc-borate HVPDs results in a drastic increase in the number of cross-linked borate species as well as the agglomeration of the polymer into bundles. These effects result in an increase in the relaxation time and thermal stability of the networks. The ability to make xPVAc-borate HVPDs with very large amounts of and rather different organic liquids, with very different rheological properties that can be controlled easily, opens new possibilities for applications of PVAc-based dispersions. © 2011 American Chemical Society

  6. Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide

    Science.gov (United States)

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  7. Characterization of indole acetic acid endophyte producers in ...

    African Journals Online (AJOL)

    Valued Acer Customer

    2015-02-18

    academicjournals.org/AJB. African Journal of Biotechnology. Full Length Research Paper. Characterization of indole acetic acid endophyte producers in authoctonus Lemna gibba plants from. Xochimilco Lake. Orlando Ortega-Acosta.

  8. Spectroscopic studies of rotational isomerism in ethyl halo acetate

    International Nuclear Information System (INIS)

    Jasem, N.A.

    1985-01-01

    Infrared spectra of ethyl flouro acetate,ethyl chloro acetate ethyl bromo acetate and ethyl iodo acetate have been recorded in the region 4000-200 cm - 1 in the solid liquid and vapour phases.The spectra have shown that some bands are increasing in intensity upon moving from the solid to the liquid and to the vapour phases and some other bands are decreasing.Vibrational frequency assignments of the fundamental modes of vibration were made enthalpy differences between these isomers were determined for each compound in each phase.The values were used as a measure of the relative stability of the isomers.Furthermore,activation energy for the conformations from one isomer into another were estimated using arrhenius equation.Effects of solvents were investigated in this work too.(39 tabs., 46 figs., 55 refs.)

  9. Degradation by acetic acid for crystalline Si photovoltaic modules

    Science.gov (United States)

    Masuda, Atsushi; Uchiyama, Naomi; Hara, Yukiko

    2015-04-01

    The degradation of crystalline Si photovoltaic modules during damp-heat test was studied using some test modules with and without polymer film insertion by observing electrical and electroluminescence properties and by chemical analyses. Acetic acid generated by the hydrolysis decomposition of ethylene vinyl acetate used as an encapsulant is the main origin of degradation. The change in electroluminescence images is explained on the basis of the corrosion of electrodes by acetic acid. On the other hand, little change was observed at the pn junction even after damp-heat test for a long time. Therefore, carrier generation occurs even after degradation; however, such generated carriers cannot be collected owing to corrosion of electrodes. The guiding principle that module structure and module materials without saving acetic acid into the modules was obtained.

  10. Densities, speeds of sound, and refractive indices of the ternary mixtures (toluene + methyl acetate + butyl acetate) and (toluene + methyl acetate + methyl heptanoate) at 298.15 K

    International Nuclear Information System (INIS)

    Mariano, Alejandra; Postigo, Miguel; Gonzalez-Salgado, Diego; Romani, Luis

    2007-01-01

    Density, ρ, speed of sound, u, and refractive index, n D , at 298.15 K and atmospheric pressure have been measured over the entire composition range for (toluene + methyl acetate + butyl acetate) and (toluene + methyl acetate + methyl heptanoate) systems. Excess molar volumes, V E , isentropic compressibility, κ s , isentropic compressibility deviations, Δκ s , and changes of refractive index on mixing, Δn D , for the above systems, have been calculated from experimental data and fitted to Cibulka, Singh et al., and Nagata and Sakura equations, standard deviations from the regression lines are shown. Geometrical solution models, Tsao and Smith, Kholer, Jacob and Fitzner, Rastogi et al. were also applied to predict ternary properties from binary contributions

  11. Acetate transiently inhibits myocardial contraction by increasing mitochondrial calcium uptake.

    Science.gov (United States)

    Schooley, James F; Namboodiri, Aryan M A; Cox, Rachel T; Bünger, Rolf; Flagg, Thomas P

    2014-12-09

    There is a close relationship between cardiovascular disease and cardiac energy metabolism, and we have previously demonstrated that palmitate inhibits myocyte contraction by increasing Kv channel activity and decreasing the action potential duration. Glucose and long chain fatty acids are the major fuel sources supporting cardiac function; however, cardiac myocytes can utilize a variety of substrates for energy generation, and previous studies demonstrate the acetate is rapidly taken up and oxidized by the heart. In this study, we tested the effects of acetate on contractile function of isolated mouse ventricular myocytes. Acute exposure of myocytes to 10 mM sodium acetate caused a marked, but transient, decrease in systolic sarcomere shortening (1.49 ± 0.20% vs. 5.58 ± 0.49% in control), accompanied by a significant increase in diastolic sarcomere length (1.81 ± 0.01 μm vs. 1.77 ± 0.01 μm in control), with a near linear dose response in the 1-10 mM range. Unlike palmitate, acetate caused no change in action potential duration; however, acetate markedly increased mitochondrial Ca(2+) uptake. Moreover, pretreatment of cells with the mitochondrial Ca(2+) uptake blocker, Ru-360 (10 μM), markedly suppressed the effect of acetate on contraction. Lehninger and others have previously demonstrated that the anions of weak aliphatic acids such as acetate stimulate Ca(2+) uptake in isolated mitochondria. Here we show that this effect of acetate appears to extend to isolated cardiac myocytes where it transiently modulates cell contraction.

  12. The reactivity of phenylethanethiolated gold nanoparticles with acetic acid.

    Science.gov (United States)

    Xia, Nan; Gan, Zibao; Liao, Lingwen; Zhuang, Shengli; Wu, Zhikun

    2017-10-24

    We report the size-dependent reactivity of phenylethanethiolated gold nanoparticles with acetic acid. Employing this reactivity, we synthesize a novel nanocluster Au 38 (PET) 26 (PET: phenylethanethiolate), which is otherwise difficult to obtain and exhibits remarkably different photoluminescence and electrochemical properties compared with the well-known Au 38 (PET) 24 nanoclusters. And the reaction process between Au 38 (PET) 26 and acetic acid was probed by matrix-assisted laser desorption/ionization time of flight mass spectrometry.

  13. Hydroxypropyl Methylcellulose Acetate Succinate: Potential Drug–Excipient Incompatibility

    OpenAIRE

    Dong, Zedong; Choi, Duk Soon

    2008-01-01

    The stability of hydroxypropyl methylcellulose acetate succinate (HPMC-AS) and its potential incompatibility with active pharmaceutical ingredients (API) carrying hydroxyl group(s) were investigated in this research. HPMC-AS may undergo hydrolysis under harsh processing conditions with the generation of succinic acid and acetic acid, which can form ester bond(s) with the hydroxyl group(s) in API. In this case, the hot-melt extrusion (HME) product prepared from HPMC-AS and our model compound (...

  14. Hydrothermal carbonization of tobacco stalk for fuel application.

    Science.gov (United States)

    Cai, Jiaxiao; Li, Bin; Chen, Chaoying; Wang, Jing; Zhao, Min; Zhang, Ke

    2016-11-01

    Tobacco stalks are an abundant biomass resource which are otherwise treated as waste. In this work, the effect of hydrothermal carbonization temperature and time on the structures, chemical compositions and combustion characteristics of hydrochars obtained from tobacco stalks were evaluated. The carbon content, higher heating value, and energy yield increased with accompanying decrease in hydrogen and oxygen contents with the increase of treatment temperature and time. The evolution of the H/C and O/C atomic ratios indicated dehydration and devolatilization processes occurred during hydrothermal carbonization. The weight loss, combustion range and characteristic temperatures of tobacco stalks were significantly modified after hydrothermal carbonization, resulting in higher ignition temperatures and higher energy density. The kinetics model, Coats-Redfern method revealed the activation energy of hydrochars in zone 2 and 3 were among 43.7-74.8kJ/mol and 46.7-85.8kJ/mol, respectively. Our results show that hydrothermal carbonization reaction can facilitate transforming tobacco stalks into energy-rich solid fuel. Copyright © 2016. Published by Elsevier Ltd.

  15. Hydrothermal synthesis and photoluminescent properties of stacked indium sulfide superstructures.

    Science.gov (United States)

    Xing, Yan; Zhang, Hongjie; Song, Shuyan; Feng, Jing; Lei, Yongqian; Zhao, Lijun; Li, Meiye

    2008-03-28

    Unusual hierarchical stacked superstructures of cubic beta-In2S3 were fabricated via a facile hydrothermal process in the presence of a surfactant cetyltrimethylammonium bromide CTAB; the 3D superstructures were developed by helical propagation of surface steps from microflakes of 10-20 nm thickness.

  16. Mapping hydrothermal altered mineral deposits using Landsat 7 ...

    Indian Academy of Sciences (India)

    The colour composite and band ratio methods showed very clearly the hydrothermal altered deposits of clay minerals, iron oxides and ferric oxides around the fumaroles. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral ...

  17. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from.

  18. Ethanol Production from Hydrothermally-Treated Biomass from West Africa

    DEFF Research Database (Denmark)

    Bensah, Edem C.; Kádár, Zsófia; Mensah, Moses Y.

    2015-01-01

    Despite the abundance of diverse biomass resources in Africa, they have received little research and development focus. This study presents compositional analysis, sugar, and ethanol yields of hydrothermal pretreated (195 degrees C, 10 min) biomass from West Africa, including bamboo wood, rubber ...

  19. Hydrothermal gold mineralization and structural controls near May ...

    African Journals Online (AJOL)

    Ezana Mining Development Company has recently reported presence of gold mineralization near May Hibey area, western Tigray, northern Ethiopia. It is in association with hydrothermal quartz veins within the Neoproterozoic low grade basement rocks, metavolcanics and metasedimentary rocks. Structural data suggests ...

  20. Facile template-free hydrothermal synthesis and microstrain ...

    Indian Academy of Sciences (India)

    Administrator

    electrodeposition (Kim et al 2006), template basis syn- thesis (Li et al 2000), thermal evaporation (Umar et al. 2006) and electrochemical deposition (Ko et al 2012). Among these techniques, preparing ZnO nanorods via hydrothermal route provides an easy and convenient method with high ability in controlling the physics ...

  1. Sol-Gel/Hydrothermal Synthesis of Mixed Metal Oxide

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal condition ... Keywords: Nanocomposites, Titanium dioxide, Zinc oxide, Particle sizes, Optical property, X-Ray Diffraction. ABSTRACT. 321 ... doping with other semiconductors like zinc oxide, aluminium oxide ...

  2. Hydrothermal liquefaction of microalgae's for bio oil production

    DEFF Research Database (Denmark)

    Toor, Saqib; Reddy, Harvind; Deng, Shuguang

    process water for algae cultivation. GC-MS, elemental analyzer, calorimeter and nutrient analysis were used to analyze bio-crude, lipid-extracted algae and water samples produced in the hydrothermal liquefaction process. The highest bio-oil yield of 46% was obtained on Nannochloropsis salina at 310 °C...

  3. Hydrothermal synthesis, characterization, and magneticproperties of cobalt chromite nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Zákutná, Dominika; Repko, A.; Matulková, I.; Nižňanský, Daniel; Ardu, A.; Cannas, C.; Mantlíková, Alice; Vejpravová, Jana

    2014-01-01

    Roč. 16, č. 2 (2014), 1-14 ISSN 1388-0764 R&D Projects: GA ČR GAP108/10/1250 Institutional support: RVO:68378271 ; RVO:61388980 Keywords : cobalt chromite * hydrothermal method * nanoparticles * size effect * multiferroic materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.184, year: 2014

  4. Hydrogen is an energy source for hydrothermal vent symbioses.

    Science.gov (United States)

    Petersen, Jillian M; Zielinski, Frank U; Pape, Thomas; Seifert, Richard; Moraru, Cristina; Amann, Rudolf; Hourdez, Stephane; Girguis, Peter R; Wankel, Scott D; Barbe, Valerie; Pelletier, Eric; Fink, Dennis; Borowski, Christian; Bach, Wolfgang; Dubilier, Nicole

    2011-08-10

    The discovery of deep-sea hydrothermal vents in 1977 revolutionized our understanding of the energy sources that fuel primary productivity on Earth. Hydrothermal vent ecosystems are dominated by animals that live in symbiosis with chemosynthetic bacteria. So far, only two energy sources have been shown to power chemosynthetic symbioses: reduced sulphur compounds and methane. Using metagenome sequencing, single-gene fluorescence in situ hybridization, immunohistochemistry, shipboard incubations and in situ mass spectrometry, we show here that the symbionts of the hydrothermal vent mussel Bathymodiolus from the Mid-Atlantic Ridge use hydrogen to power primary production. In addition, we show that the symbionts of Bathymodiolus mussels from Pacific vents have hupL, the key gene for hydrogen oxidation. Furthermore, the symbionts of other vent animals such as the tubeworm Riftia pachyptila and the shrimp Rimicaris exoculata also have hupL. We propose that the ability to use hydrogen as an energy source is widespread in hydrothermal vent symbioses, particularly at sites where hydrogen is abundant.

  5. Hydrothermal liquefaction of barley straw to bio-crude oil

    DEFF Research Database (Denmark)

    Zhu, Zhe; Rosendahl, Lasse; Toor, Saqib

    2015-01-01

    Hydrothermal liquefaction (HTL) of barley straw with K2CO3 at different temperatures (280–400 C) was conducted and compared to optimize its process conditions; the aqueous phase as a co-product from this process was recycled to explore the feasibility of implementing wastewater reuse for bio...

  6. Synthesis of ZrO2 nanoparticles by hydrothermal treatment

    International Nuclear Information System (INIS)

    Machmudah, Siti; Widiyastuti, W.; Prastuti, Okky Putri; Nurtono, Tantular; Winardi, Sugeng; Wahyudiono,; Kanda, Hideki; Goto, Motonobu

    2014-01-01

    Zirconium oxide (zirconia, ZrO 2 ) is the most common material used for electrolyte of solid oxide fuel cells (SOFCs). Zirconia has attracted attention for applications in optical coatings, buffer layers for growing superconductors, thermal-shield, corrosion resistant coatings, ionic conductors, and oxygen sensors, and for potential applications including transparent optical devices and electrochemical capacitor electrodes, fuel cells, catalysts, and advanced ceramics. In this work, zirconia particles were synthesized from ZrCl 4 precursor with hydrothermal treatment in a batch reactor. Hydrothermal treatment may allow obtaining nanoparticles and sintered materials with controlled chemical and structural characteristics. Hydrothermal treatment was carried out at temperatures of 150 – 200°C with precursor concentration of 0.1 – 0.5 M. Zirconia particles obtained from this treatment were analyzed by using SEM, PSD and XRD to characterize the morphology, particle size distribution, and crystallinity, respectively. Based on the analysis, the size of zirconia particles were around 200 nm and it became smaller with decreasing precursor concentration. The increasing temperature caused the particles formed having uniform size. Zirconia particles formed by hydrothermal treatment were monoclinic, tetragonal and cubic crystal

  7. thermal power stations' reliability evaluation in a hydrothermal system

    African Journals Online (AJOL)

    Dr Obe

    A quantitative tool for the evaluation of thermal power stations reliability in a hydrothermal system is presented. A reliable power station is one which would supply the required power within its installed capacity at any time within the specified voltage and frequency limits. Required for this evaluation are the station's installed ...

  8. Hydrothermal synthesis of titania powders and their photocatalyc properties

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Bakardjieva, Snejana; Murafa, Nataliya; Houšková, Vendula

    2008-01-01

    Roč. 52, č. 4 (2008), s. 278-290 ISSN 0862-5468 R&D Projects: GA ČR GA203/08/0334 Institutional research plan: CEZ:AV0Z40320502 Keywords : anatase * rutile * hydrothermal synthesis Subject RIV: CA - Inorganic Chemistry Impact factor: 0.644, year: 2008

  9. Borehole plugging by hydrothermal transport. A feasibility report

    Energy Technology Data Exchange (ETDEWEB)

    Roy, D.M.; White, W.B.

    1975-05-30

    The possibility of forming borehole plugs by hydrothermal transport was examined with respect to five systems, utilizing available literature data. In general, it would appear possible to create plugs with hydrothermal cements, with hydrothermally transported quartz, and with carbonates precipitated in-situ using carbon dioxide or carbon dioxide and water as reacting fluids. Hydrothermal cements appear to be most feasible from an engineering and economic point of view using a slurry with a lime-alumina-silica composition carried into the hole in a single pipe at temperatures in the range of 200/sup 0/C and requiring only enough pressure to drive the mixture into the hole. Quartz or chalcedony plugs would be the most impervious, have the lowest chemical reactivity with groundwater, the lowest thermal expansion, and be most compatible with the wall rock. Deposition is likely to be slow, and there are severe engineering problems associated with a single pipe system carrying silica-rich solutions at temperatures in excess of 500/sup 0/C at pressure of 2000 bars (30,000 psi). Calcite plugs could be formed as compatible plug materials in contact with a limestone or dolomite wall rock. It is not known whether non-porous plugs can be readily formed and there is also a problem of chemical reaction with percolating groundwater. The clay-water and sulfur-water systems do not appear to be viable plug systems. In-situ reconstitution of the wall rock does not appear to be an economically feasible possibility.

  10. Hydrothermal assessment of temporal variability in seedbed microclimate

    Science.gov (United States)

    Stuart P. Hardegree; Corey A. Moffet; Gerald N. Flerchinger; Jaepil Cho; Bruce A. Roundy; Thomas A. Jones; Jeremy J. James; Patrick E. Clark; Frederick B. Pierson

    2013-01-01

    The microclimatic requirements for successful seedling establishment are much more restrictive than those required for adult plant survival. The purpose of the current study was to use hydrothermal germination models and a soil energy and water flux model to evaluate intra- and interannual variability in seedbed microclimate relative to potential germination response...

  11. Hydrothermal emergence model for ripgut brome (Bromus diandrus)

    Science.gov (United States)

    A model that describes the emergence of ripgut brome (Bromus diandrus) was developed using a two-season data set from a no-tilled field in northeastern Spain. The relationship between cumulative emergence and hydrothermal time (HTT) was described by a sigmoid growth function (Chapman equation). HTT ...

  12. Mineralization of Alvinella polychaete tubes at hydrothermal vents.

    Science.gov (United States)

    Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

    2015-03-01

    Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs. © 2014 The Authors. Geobiology Published by John Wiley & Sons Ltd.

  13. Inversion Approach For Thermal Data From A Convecting Hydrothermal System

    Energy Technology Data Exchange (ETDEWEB)

    Kasameyer, P.; Younker, L.; Hanson, J.

    1985-01-01

    Hydrothermal systems are often studied by collecting thermal gradient data and temperature depth curves. These data contain important information about the flow field, the evolution of the hydrothermal system, and the location and nature of the ultimate heat sources. Thermal data are conventionally interpreted by the ''forward'' method; the thermal field is calculated based on selected initial conditions and boundary conditions such as temperature and permeability distributions. If the calculated thermal field matches the data, the chosen conditions are inferred to be possibly correct. Because many sets of initial conditions may produce similar thermal fields, users of the ''forward'' method may inadvertently miss the correct set of initial conditions. Analytical methods for ''inverting'' data also allow the determination of all the possible solutions consistent with the definition of the problem. In this paper we suggest an approach for inverting thermal data from a hydrothermal system, and compare it to the more conventional approach. We illustrate the difference in the methods by comparing their application to the Salton Sea Geothermal Field by Lau (1980a) and Kasameyer, et al. (1984). In this particular example, the inverse method was used to draw conclusions about the age and total rate of fluid flow into the hydrothermal system.

  14. Hydrothermal Gold Mineralization and Structural Controls near May ...

    African Journals Online (AJOL)

    Mickiale

    ABSTRACT. Ezana Mining Development Company has recently reported presence of gold mineralization near. May Hibey area, western Tigray, northern Ethiopia. It is in association with hydrothermal quartz veins within the Neoproterozoic low grade basement rocks, metavolcanics and metasedimentary rocks. Structural ...

  15. Facile template-free hydrothermal synthesis and microstrain ...

    Indian Academy of Sciences (India)

    Administrator

    method with high ability in controlling the physics of rods. Hydrothermal processing has some major differences from other techniques such as preparing the powders di- rectly from solution, ability to control the shape and size of structures, being highly reactive in sintering and not needed in calcination and milling process ( ...

  16. development of a hydrothermal method to synthesize spherical znse

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Hydrothermal method was used to synthesize pure ZnSe nanosphere materials. The effects of the reducing agent amount, the reaction time and temperature were investigated on the purity of ZnSe. Also, the effects of surfactants such as sodium dodecyl sulfate (SDS) (anionic) and cetyl trimethylammonium ...

  17. Highly Hydrothermally Stable Microporous Membranes for Hydroge Separation

    NARCIS (Netherlands)

    Wei, Qi; Wang, Fei; Wang, F.; Nie, Zuo-Ren; Song, C.; Wang, Yan-Li; Li, Qun-Yan

    2008-01-01

    Fluorocarbon-modified silica membranes were deposited on γ-Al2O3/α-Al2O3 supports by the sol−gel technique for hydrogen separation. The hydrophobic property, pore structure, gas transport and separation performance, and hydrothermal stability of the modified membranes were investigated. It is

  18. Explorations of Mariana Arc Volcanoes Reveal New Hydrothermal Systems

    Science.gov (United States)

    Embley, R. W.; Baker, E. T.; Chadwick, W. W., Jr.; Lupton, J. E.; Resing, J. A.; Massoth, G. J.; Nakamura, K.

    2004-01-01

    Some 20,000 km of volcanic arcs, roughly one-third the length of the global mid-ocean ridge (MOR) system, rim the western Pacific Ocean. Compared to 25 years of hydrothermal investigations along MORs, exploration of similar activity on the estimated ~600 submarine arc volcanoes is only beginning [Ishibashi and Urabe, 1995; De Ronde et al., 2003]. To help alleviate this under-sampling, the R/V T. G. Thompson was used in early 2003 (9 February to 5 March) to conduct the first complete survey of hydrothermal activity along 1200 km of the Mariana intra-oceanic volcanic arc. This region includes both the Territory of Guam and the Commonwealth of the Northern Mariana Islands. The expedition mapped over 50 submarine volcanoes with stunning new clarity (Figures 1 and 2) and found active hydrothermal discharge at 12 sites, including the southern back-arc site. This includes eight new sites along the arc (West Rota, Northwest Rota, E. Diamante, Zealandia Bank, Maug Caldera, Ahyi, Daikoku, and Northwest Eifuku) and four sites of previously known hydrothermal activity (Seamount X, Esmeralda, Kasuga 2, and Nikko) (Figures 1 and 2). The mapping also fortuitously provided a ``before'' image of the submarine flanks of Anatahan Island, which had its first historical eruption on 10 May 2003 (Figures 1 and 3).

  19. hydrothermal synthesis and characterisation of amine-templated

    African Journals Online (AJOL)

    PROF EKWUEME

    showed that the complexes were insoluble in water, ethanol, DMF and DMSO. KEYWORDS: Hydrothermal synthesis, metal phosphates, p-aminobenzoic acid, ethylacetoacetate, ethylammonium-. 4-aminobenzoate. INTRODUCTION. One of the major areas of materials science is the development of solid state materials with ...

  20. Origin of Magnetism in Hydrothermally Aged 2-Line Ferrihydrite Suspensions.

    Science.gov (United States)

    Cao, Liang; Jiang, Zhao-Xia; Du, Yong-Hua; Yin, Xin-Mao; Xi, Shi-Bo; Wen, Wen; Roberts, Andrew P; Wee, Andrew T S; Xiong, Yi-Min; Liu, Qing-Song; Gao, Xing-Yu

    2017-03-07

    As an iron oxyhydroxide, nanosized ferrihydrite (Fh) is important in Earth science, biology, and industrial applications. However, its basic structure and origin of its magnetism have long been debated. We integrate synchrotron-based techniques to explore the chemical structures of 2-line ferrihydrite and to determine the origin of its magnetism during hydrothermal aging in air. Our results demonstrate that both the magnetism and X-ray magnetic circular dichroism (XMCD) signal of 2-line ferrihydrite are enhanced with aging time, and that XMCD spectral patterns resemble that of maghemite (γ-Fe 2 O 3 ) rather than magnetite (Fe 3 O 4 ). Fe L-edge and K-edge X-ray absorption spectroscopy (XAS) further indicate formation of both maghemite and hematite (α-Fe 2 O 3 ) with increasing concentrations with longer hydrothermal aging time. Thus, magnetic enhancement with longer hydrothermal aging time is attributed to increasing maghemite concentration instead of a magnetically ordered ferrihydrite as previously reported. Moreover, L-edge and K-edge XAS spectra with different probing depths yield different ratios of these Fe oxides, which suggest the formation of a core (ferrihydrite-rich)-shell (with a mixture of both allotropes; α-Fe 2 O 3 and γ-Fe 2 O 3 ) structure during hydrothermal aging. Our results provide insights into the chemical evolution of 2-line ferrihydrite that reveal unambiguously the origin of its magnetism.

  1. Mapping hydrothermal altered mineral deposits using Landsat 7 ...

    Indian Academy of Sciences (India)

    spatial patterns of alteration makes the 'remote sensing technique' one of the standard procedures in exploration geology, due to its high efficiency and low cost (Yetkin 2003). There are many studies around the world related to hydrothermal alteration mapping using multi- spectral satellite images especially, Landsat and.

  2. Mapping hydrothermal altered mineral deposits using Landsat 7 ...

    Indian Academy of Sciences (India)

    To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7. ETM+ image in and around ... component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and ..... target detection algorithms for hyperspectral imagery; In: Algorithms and ...

  3. thermal power stations' reliability evaluation in a hydrothermal system

    African Journals Online (AJOL)

    Dr Obe

    R. C. OKONKWO. Department of Electrical Engineering. UNIVERSITY OF NIGERIA. NSUKKA. ABSTRACT. A quantitative tool for the evaluation of thermal power stations reliability in a hydrothermal system is presented. A reliable power station is one which would supply the required power within its installed capacity at any ...

  4. Load frequency control of three area interconnected hydro-thermal ...

    African Journals Online (AJOL)

    This paper present analysis on dynamic performance of Load Frequency Control (LFC) of three area interconnected hydrothermal reheat power system by the use of Artificial Intelligent and PI Controller. In the proposed scheme, control methodology developed using conventional PI controller, Artificial Neural Network ...

  5. Metaproteogenomic Profiling of Microbial Communities Colonizing Actively Venting Hydrothermal Chimneys

    Directory of Open Access Journals (Sweden)

    Petra Pjevac

    2018-04-01

    Full Text Available At hydrothermal vent sites, chimneys consisting of sulfides, sulfates, and oxides are formed upon contact of reduced hydrothermal fluids with oxygenated seawater. The walls and surfaces of these chimneys are an important habitat for vent-associated microorganisms. We used community proteogenomics to investigate and compare the composition, metabolic potential and relative in situ protein abundance of microbial communities colonizing two actively venting hydrothermal chimneys from the Manus Basin back-arc spreading center (Papua New Guinea. We identified overlaps in the in situ functional profiles of both chimneys, despite differences in microbial community composition and venting regime. Carbon fixation on both chimneys seems to have been primarily mediated through the reverse tricarboxylic acid cycle and fueled by sulfur-oxidation, while the abundant metabolic potential for hydrogen oxidation and carbon fixation via the Calvin–Benson–Bassham cycle was hardly utilized. Notably, the highly diverse microbial community colonizing the analyzed black smoker chimney had a highly redundant metabolic potential. In contrast, the considerably less diverse community colonizing the diffusely venting chimney displayed a higher metabolic versatility. An increased diversity on the phylogenetic level is thus not directly linked to an increased metabolic diversity in microbial communities that colonize hydrothermal chimneys.

  6. Rapid hydrothermal route to synthesize cubic-phase gadolinium ...

    Indian Academy of Sciences (India)

    Administrator

    Dhananjaya et al 2012a, b), vapour-phase transport pro- cess (Wu and Yang 2000) and .... The colloids, while partially dissolved in water results in a metastable super- saturated solution under hydrothermal environment. On cooling back to room temperature, a large number of seed particles of Gd(OH)3 were formed ...

  7. Hydrothermally stable molecular separation membranes from organically linked silica

    NARCIS (Netherlands)

    Castricum, H.L.; Ashima sah, A.S.; Kreiter, Robert; Blank, David H.A.; Vente, Jaap F.; ten Elshof, Johan E.

    2008-01-01

    A highly hydrothermally stable microporous network material has been developed that can be applied in energy-efficient molecular sieving. The material was synthesized by employing organically bridged monomers in acid-catalysed sol–gel hydrolysis and condensation, and is composed of covalently bonded

  8. Hydrothermally stable molecular separation membranes from organically linked silica

    NARCIS (Netherlands)

    Castricum, H.L.; Sah, A.; Kreiter, R.; Blank, D.H.A.; Vente, J.F.; ten Elshof, J.E.

    2008-01-01

    A highly hydrothermally stable microporous network material has been developed that can be applied in energy-efficient molecular sieving. The material was synthesized by employing organically bridged monomers in acid-catalysed sol-gel hydrolysis and condensation, and is composed of covalently bonded

  9. Hydrothermal synthesis and characterisation of amine-templated ...

    African Journals Online (AJOL)

    Hydrothermal synthesis and characterisation of amine-templated metal phosphate framework. ... The complexes were thermally stable up to 3000C, after which the organic components starts decomposing. The solubility test in a wide spectrum of solvents (at room temperature) showed that the complexes were insoluble in ...

  10. Borehole plugging by hydrothermal transport. A feasibility report

    International Nuclear Information System (INIS)

    Roy, D.M.; White, W.B.

    1975-01-01

    The possibility of forming borehole plugs by hydrothermal transport was examined with respect to five systems, utilizing available literature data. In general, it would appear possible to create plugs with hydrothermal cements, with hydrothermally transported quartz, and with carbonates precipitated in-situ using carbon dioxide or carbon dioxide and water as reacting fluids. Hydrothermal cements appear to be most feasible from an engineering and economic point of view using a slurry with a lime-alumina-silica composition carried into the hole in a single pipe at temperatures in the range of 200 0 C and requiring only enough pressure to drive the mixture into the hole. Quartz or chalcedony plugs would be the most impervious, have the lowest chemical reactivity with groundwater, the lowest thermal expansion, and be most compatible with the wall rock. Deposition is likely to be slow, and there are severe engineering problems associated with a single pipe system carrying silica-rich solutions at temperatures in excess of 500 0 C at pressure of 2000 bars (30,000 psi). Calcite plugs could be formed as compatible plug materials in contact with a limestone or dolomite wall rock. It is not known whether non-porous plugs can be readily formed and there is also a problem of chemical reaction with percolating groundwater. The clay-water and sulfur-water systems do not appear to be viable plug systems. In-situ reconstitution of the wall rock does not appear to be an economically feasible possibility

  11. Roots of Acetate-Vanadium Linkage Isomerism: A QTAIM Study.

    Science.gov (United States)

    Teixeira, Filipe; Mosquera, Ricardo; Melo, André; Freire, Cristina; Cordeiro, M Natália D S

    2016-04-04

    The possibility of linkage isomerism in a number of vanadium(IV) and vanadium(V) complexes with acetate was surveyed using Density Functional Theory (DFT) and Bader's Quantum Theory of Atoms in Molecules (QTAIM). The results show that vanadium-acetate linkages may be classified as bidentate symmetrical, bidentate asymmetrical, or monodentate, the latter being observed in about 40% of the cases. These latter ones correspond to situations where the two oxygen atoms of the acetate moiety are not equivalent. They are associated with an energy penalty of about 263 kJ·mol(-1), as determined by the distribution of the scaled kinetic energy of the atomic basins forming the acetate ligand. In the presence of bidentate symmetrical vanadium-acetate linkages, the inner valence-shell charge concentrations on the vanadium atom deviate from the traditional VSEPR-derived arrangement, with an energy penalty of about 780 kJ·mol(-1). A compromise situation is partially accomplished in the case of bidentate asymmetrical linkages, which allow a Gillespiean-like arrangement of the inner valence-shell charge concentrations. In this case, one of these local charge concentrations lies close to a V-OAcO bond, which slightly disrupts the equivalence between the two oxygen atoms in the acetate ligand.

  12. Fixing of metallic acetates on an anion-exchange resin

    International Nuclear Information System (INIS)

    Brigaudeau-Vaissiere, M.

    1966-06-01

    After giving a brief review of the theoretical principles governing the fixation of anionic complexes of metallic elements on an anion exchange resin, we consider the particular case of uranyl acetate. By plotting the partition curves we have been able to calculate the exchange constants in the resin. By studying the changes in the logarithm of the limiting partition coefficient as a function of the logarithm of the free acetate ion concentration, it has been possible to calculate the dissociation constants for the complexes in solution. The fixation of a large number of metallic acetates has been studied. All the tests have been negative except in the case of mercury. For this reason we have been able to consider the possibility of separating uranium from a certain number of elements. Some of these separations are possible even in the presence of interfering anions such as chlorides which have a greater affinity for the resin than have the acetate ions. In the case of water-ethanol and water-isopropanol mixtures, we have improved the conditions under which copper acetate and mercury acetate may be fixed. This study has enabled us to calculate the dissociation constant for the CuAc 3 - complex in the mixtures water +40% (by weight) isopropanol and water +50% (by weight) isopropanol. It should also make it possible to use separation conditions which could not hitherto be applied in aqueous media. (author) [fr

  13. Ethyl acetate production by the elusive alcohol acetyltransferase from yeast.

    Science.gov (United States)

    Kruis, Aleksander J; Levisson, Mark; Mars, Astrid E; van der Ploeg, Max; Garcés Daza, Fernando; Ellena, Valeria; Kengen, Servé W M; van der Oost, John; Weusthuis, Ruud A

    2017-05-01

    Ethyl acetate is an industrially relevant ester that is currently produced exclusively through unsustainable processes. Many yeasts are able to produce ethyl acetate, but the main responsible enzyme has remained elusive, hampering the engineering of novel production strains. Here we describe the discovery of a new enzyme (Eat1) from the yeast Wickerhamomyces anomalus that resulted in high ethyl acetate production when expressed in Saccharomyces cerevisiae and Escherichia coli. Purified Eat1 showed alcohol acetyltransferase activity with ethanol and acetyl-CoA. Homologs of eat1 are responsible for most ethyl acetate synthesis in known ethyl acetate-producing yeasts, including S. cerevisiae, and are only distantly related to known alcohol acetyltransferases. Eat1 is therefore proposed to compose a novel alcohol acetyltransferase family within the α/β hydrolase superfamily. The discovery of this novel enzyme family is a crucial step towards the development of biobased ethyl acetate production and will also help in selecting improved S. cerevisiae brewing strains. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  14. Mitigation of radiation injury by polyphenolic acetates

    International Nuclear Information System (INIS)

    Venkateswaran, Kavya; Singh, Saurabh; Agrawala, Paban K.

    2014-01-01

    Polyphenols are naturally occurring heterocyclic compounds, which have diverse biological and pharmacological implications. Calreticulin mediated protein acetylation (CRTase) system has been recently demonstrated by our groups using semi-synthetic polyphenolic acetates (PA) as the acetyl group donor. Owing to the anti-oxidant property of the parental moiety (polyphenols) coupled with the acetyl group donating ability; PAs have the potential to be developed as countermeasure agents against radiation damage. Therefore, we investigated the protective and mitigative potential of PAs namely 7,8-diacetoxy-4-methylcoumarin (DAMC) and 7,8-diacetoxy-4-methylthiocoumarin (DAMTC) in total body irradiated (TBI) mice. These compounds exhibited protective as well as mitigative potential against lethal dose of radiation, with ∼ 80% survival conferred by DAMTC when administered 24 h post TBl. A 3.8 fold increase in the number of splenic colonies at day 10 post TBI in the DAMTC treated mice as visualised by the endogenous spleen colony forming assay suggested amelioration of radiation induced hematopoietic injury. A significant recovery in the numbers of WBCs and lymphocytes was noted on day 21 post TBI by DAMTC with a ∼ 2.6 fold increase for WBCs and ∼ 6.5 for lymphocytes. DAMTC reduced the radiation induced apoptosis and increased cell proliferation in the bone marrow and spleen at days 3 and 21 post TBI corroborating its potency in stimulating hematopoietic recovery after TBl. Histopathology revealed ∼ 3 fold and ∼ 2.2 fold increases in the numbers of intestinal crypts on days 3 and 7 respectively in the DAMTC treated mice. A significant increase (∼ 3.5 and ∼ 2.9 fold) in the villi length was observed on days 3 and 7 respectively, accompanied by a concomitant increase in the crypt height by ∼ 3.5 folds. These results establish the potential of DAMTC to mitigate acute effects of radiation that appear to stem from its ability to ameliorate radiation induced

  15. First Survey For Submarine Hydrothermal Vents In NE Sulawesi, Indonesia

    Science.gov (United States)

    McConachy, T.; Binns, R.; Permana, H.

    2001-12-01

    The IASSHA-2001 cruise (Indonesia-Australia Survey for Submarine Hydrothermal Activity) was successfully conducted from June 1 to June 29 on board Baruna Jaya VIII. Preliminary results are reported of the first expedition to locate and study submarine hydrothermal activity in north east Sulawesi. Leg A focussed on Tomini Bay, a virtually unexplored Neogene sedimentary basin. Its objective was to test whether modern sediment-hosted hydrothermal activity occurred on the sea floor. The results of new bathymetric mapping, sediment coring and CTD/transmissometer hydrocasts negate the likely presence in central Tomini Bay of large-scale modern analogues of hydrothermal massive sulfide environments involving hydrothermal venting of basinal or magma-derived fluids into reduced sediments. It is possible that the "heat engine" required to drive circulation of basinal and hydrothermal fluids is today too weak. Surveys around Colo volcano indicate that it may be in its final stage of evolution. Leg B studied the arc and behind-arc sectors of the Sangihe volcanic island chain extending northwards from Quaternary volcanoes on the northeastern tip of Sulawesi's North Arm, near Manado. West of the main active chain and extending northwards from Manado there is a subparallel ridge surmounted by a number of high (>2000 m) seamounts of uncertain age. Fifteen relatively high-standing submarine edifices were crossed during this leg, of which nine were tested for hydrothermal activity by hydrocast and dredging. Eight sites were known from previous bathymetric surveys, and seven are new discoveries made by narrow-beam or multibeam echo sounding. Two submarine edifices at least 1000 m high were discovered in the strait immediately north of Awu volcano on Sangihe Island. One, with crest at 206 m, is surrounded by a circular platform 300m deep which we infer to be a foundered fringing reef to a formerly emergent island. The other, lacking such a platform, appears relatively young and may be

  16. Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds

    Science.gov (United States)

    Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik

    2016-10-01

    Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline hydrothermal vents (Russell et al., 2014). Hydrothermal chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311-318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm. 51

  17. Hydrothermal impacts on trace element and isotope ocean biogeochemistry.

    Science.gov (United States)

    German, C R; Casciotti, K A; Dutay, J-C; Heimbürger, L E; Jenkins, W J; Measures, C I; Mills, R A; Obata, H; Schlitzer, R; Tagliabue, A; Turner, D R; Whitby, H

    2016-11-28

    Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, the calculated rate of entrainment of the entire ocean volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable to that of deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within deep-ocean hydrothermal plumes have long been known to have the potential to impact global-scale biogeochemical cycles. More recently, new results from GEOTRACES have revealed that plumes rich in dissolved Fe, an important micronutrient that is limiting to productivity in some areas, are widespread above mid-ocean ridges and extend out into the deep-ocean interior. While Fe is only one element among the full suite of TEIs of interest to GEOTRACES, these preliminary results are important because they illustrate how inputs from seafloor venting might impact the global biogeochemical budgets of many other TEIs. To determine the global impact of seafloor venting, however, requires two key questions to be addressed: (i) What processes are active close to vent sites that regulate the initial high-temperature hydrothermal fluxes for the full suite of TEIs that are dispersed through non-buoyant hydrothermal plumes? (ii) How do those processes vary, globally, in response to changing geologic settings at the seafloor and/or the geochemistry of the overlying ocean water? In this paper, we review key findings from recent work in this realm, highlight a series of key hypotheses arising from that research and propose a series of new GEOTRACES modelling, section and process studies that could be implemented, nationally and internationally, to address these issues.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2015 The Authors.

  18. Hydrothermal activity at the Arctic mid-ocean ridges

    Science.gov (United States)

    Pedersen, Rolf B.; Thorseth, Ingunn H.; Nygård, Tor Eivind; Lilley, Marvin D.; Kelley, Deborah S.

    Over the last 10 years, hydrothermal activity has been shown to be abundant at the ultraslow spreading Arctic Mid-Ocean Ridges (AMOR). Approximately 20 active and extinct vent sites have been located either at the seafloor, as seawater anomalies, or by dredge sampling hydrothermal deposits. Decreasing spreading rates and decreasing influence of the Icelandic hot spot toward the north along the AMOR result in a north-south change from a shallow and magmatically robust to a deep and magmatically starved ridge system. This contrast gives rise to large variability in the ridge geology and in the nature of the associated hydrothermal systems. The known vent sites at the southern part of the ridge system are either low-temperature or white smoker fields. At the deep, northern parts of the ridge system, a large black smoker field has been located, and seawater anomalies and sulfide deposits suggest that black smoker-type venting is common. Several of these fields may be peridotite-hosted. The hydrothermal activity at parts of the AMOR exceeds by a factor of 2 to 3 what would be expected by extrapolating from observations on faster spreading ridges. Higher fracture/fault area relative to the magma volume extracted seems a likely explanation for this. Many of the vent fields at the AMOR are associated with axial volcanic ridges. Strong focusing of magma toward these ridges, deep rifting of the ridges, and subsequent formation of long-lived detachment faults that are rooted below the ridges may be the major geodynamic mechanisms causing the unexpectedly high hydrothermal activity.

  19. Learning about hydrothermal volcanic activity by modeling induced geophysical changes

    Science.gov (United States)

    Currenti, Gilda M.; Napoli, Rosalba

    2017-05-01

    Motivated by ongoing efforts to understand the nature and the energy potential of geothermal resources, we devise a coupled numerical model (hydrological, thermal, mechanical), which may help in the characterization and monitoring of hydrothermal systems through computational experiments. Hydrothermal areas in volcanic regions arise from a unique combination of geological and hydrological features which regulate the movement of fluids in the vicinity of magmatic sources capable of generating large quantities of steam and hot water. Numerical simulations help in understanding and characterizing rock-fluid interaction processes and the geophysical observations associated with them. Our aim is the quantification of the response of different geophysical observables (i.e. deformation, gravity and magnetic field) to hydrothermal activity on the basis of a sound geological framework (e.g. distribution and pathways of the flows, the presence of fractured zones, caprock). A detailed comprehension and quantification of the evolution and dynamics of the geothermal systems and the definition of their internal state through a geophysical modeling approach are essential to identify the key parameters for which the geothermal system may fulfill the requirements to be exploited as a source of energy. For the sake of illustration only, the numerical computations are focused on a conceptual model of the hydrothermal system of Vulcano Island by simulating a generic 1-year unrest and estimating different geophysical changes. We solved (i) the mass and energy balance equations of flow in porous media for temperature, pressure and density changes, (ii) the elastostatic equation for the deformation field and (iii) the Poisson’s equations for gravity and magnetic potential fields. Under the model assumptions, a generic unrest of 1-year engenders on the ground surface low amplitude changes in the investigated geophysical observables, that are, however, above the accuracies of the modern

  20. The origin of methanethiol in midocean ridge hydrothermal fluids.

    Science.gov (United States)

    Reeves, Eoghan P; McDermott, Jill M; Seewald, Jeffrey S

    2014-04-15

    Simple alkyl thiols such as methanethiol (CH3SH) are widely speculated to form in seafloor hot spring fluids. Putative CH3SH synthesis by abiotic (nonbiological) reduction of inorganic carbon (CO2 or CO) has been invoked as an initiation reaction for the emergence of protometabolism and microbial life in primordial hydrothermal settings. Thiols are also presumptive ligands for hydrothermal trace metals and potential fuels for associated microbial communities. In an effort to constrain sources and sinks of CH3SH in seafloor hydrothermal systems, we determined for the first time its abundance in diverse hydrothermal fluids emanating from ultramafic, mafic, and sediment-covered midocean ridge settings. Our data demonstrate that the distribution of CH3SH is inconsistent with metastable equilibrium with inorganic carbon, indicating that production by abiotic carbon reduction is more limited than previously proposed. CH3SH concentrations are uniformly low (∼10(-8) M) in high-temperature fluids (>200 °C) from all unsedimented systems and, in many cases, suggestive of metastable equilibrium with CH4 instead. Associated low-temperature fluids (<200 °C) formed by admixing of seawater, however, are invariably enriched in CH3SH (up to ∼10(-6) M) along with NH4(+) and low-molecular-weight hydrocarbons relative to high-temperature source fluids, resembling our observations from a sediment-hosted system. This strongly implicates thermogenic interactions between upwelling fluids and microbial biomass or associated dissolved organic matter during subsurface mixing in crustal aquifers. Widespread thermal degradation of subsurface organic matter may be an important source of organic production in unsedimented hydrothermal systems and may influence microbial metabolic strategies in cooler near-seafloor and plume habitats.

  1. Spontaneous and Widespread Electricity Generation in Natural Deep-Sea Hydrothermal Fields.

    Science.gov (United States)

    Yamamoto, Masahiro; Nakamura, Ryuhei; Kasaya, Takafumi; Kumagai, Hidenori; Suzuki, Katsuhiko; Takai, Ken

    2017-05-15

    Deep-sea hydrothermal vents discharge abundant reductive energy into oxidative seawater. Herein, we demonstrated that in situ measurements of redox potentials on the surfaces of active hydrothermal mineral deposits were more negative than the surrounding seawater potential, driving electrical current generation. We also demonstrated that negative potentials in the surface of minerals were widespread in the hydrothermal fields, regardless of the proximity to hydrothermal fluid discharges. Lab experiments verified that the negative potential of the mineral surface was induced by a distant electron transfer from the hydrothermal fluid through the metallic and catalytic properties of minerals. These results indicate that electric current is spontaneously and widely generated in natural mineral deposits in deep-sea hydrothermal fields. Our discovery provides important insights into the microbial communities that are supported by extracellular electron transfer and the prebiotic chemical and metabolic evolution of the ocean hydrothermal systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The importance of shallow hydrothermal island arc systems in ocean biogeochemistry

    Science.gov (United States)

    Hawkes, Jeffrey A.; Connelly, Douglas P.; Rijkenberg, Micha J. A.; Achterberg, Eric P.

    2014-02-01

    Hydrothermal venting often occurs at submarine volcanic calderas on island arc chains, typically at shallower depths than mid-ocean ridges. The effect of these systems on ocean biogeochemistry has been under-investigated to date. Here we show that hydrothermal effluent from an island arc caldera was rich in Fe(III) colloids (0.02-0.2 µm; 46% of total Fe), contributing to a fraction of hydrothermal Fe that was stable in ocean water. Iron(III) colloids from island arc calderas may be transferred into surrounding waters (generally 0-1500 m depth) by ocean currents, thereby potentially stimulating surface ocean primary productivity. Hydrothermal Fe oxyhydroxide particles (>0.2 µm) were also pervasive in the studied caldera and contained high concentrations of oxyanions of phosphorus (P), vanadium (V), arsenic (As), and manganese (Mn). Hydrothermal island arcs may be responsible for > 50% of global hydrothermal P scavenging and > 40% V scavenging, despite representing global hydrothermal fluid flow.

  3. Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass – the “hydrothermal pump hypothesis”

    Directory of Open Access Journals (Sweden)

    J.-P. Duda

    2018-03-01

    Full Text Available Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic. In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia. Catalytic hydropyrolysis (HyPy of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤  n-C18 is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer–Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis.

  4. Isothermal (vapour + liquid) equilibrium (VLE) for binary mixtures containing diethyl carbonate, phenyl acetate, diphenyl carbonate, or ethyl acetate

    International Nuclear Information System (INIS)

    Ho, Hsiao-Yun; Shu, So-Siou; Wang, San-Jang; Lee, Ming-Jer

    2015-01-01

    Highlights: • Isothermal (vapour + liquid) equilibrium (VLE) data were measured. • Binary mixtures contain ethyl acetate, diethyl carbonate, phenyl acetate, diphenyl carbonate. • No azeotrope formed in the systems investigated. • The VLE data were correlated well with Wilson-HOC, NRTL-HOC, UNIQUAC-HOC models. - Abstract: The isothermal (vapour + liquid) equilibrium (VLE) (P–T–x i –y i ) was determined the binary systems of (ethyl acetate + diethyl carbonate) from T = (373.2 to 453.2) K, (ethyl acetate + phenyl acetate) at T = 373.2 K, and (diethyl carbonate + phenyl acetate) at T = 373.2 K, while the VLE (P–T–x i ) of three diphenyl carbonate-containing binary systems was also determined experimentally at temperatures from (373.2 to 453.2) K. The experimental results show no azeotrope formation and near ideal solution behaviour for each binary system. These new VLE (P–T–x i –y i ) data have been passed by the point, area, and infinite dilution thermodynamic consistency tests. The Wilson-HOC, the NRTL-HOC, and the UNIQUAC-HOC models were applied to correlate the VLE results and the optimal values of the model parameters have been determined through data reduction. Comparable results were obtained from these three models.

  5. Tetrazole acetic acid: Tautomers, conformers, and isomerization

    Energy Technology Data Exchange (ETDEWEB)

    Araujo-Andrade, C. [Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas (Mexico); Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Reva, I., E-mail: reva@qui.uc.pt; Fausto, R. [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal)

    2014-02-14

    Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0–8 kJ mol{sup −1} energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol{sup −1}) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol{sup −1}). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm{sup −1}, where the first OH stretching overtone

  6. Catalytic hydrothermal gasification of biomass for the production of synthetic natural gas[Dissertation 17100

    Energy Technology Data Exchange (ETDEWEB)

    Waldner, M. H.

    2007-07-01

    operating plant on a laboratory scale (throughput 1 kg/hr, which yields about 200 L{sub SNG}/hr with a thermal heating power of 1 kW{sub th} for a feed concentration of 40 wt %). Ideally, the pilot plant should be capable of conveying solid containing slurries. Various catalysts were selected (some of them were synthesized in-house) and tested for their stability under hydrothermal conditions and for their tolerance towards inorganic salts (sulfate was chosen as model substance for these tests). The catalysts were characterized by numerous techniques (such as TG/FTIR, TPO/TPR, TOC, BET, XRD, XPS, ICP, TEM, HAADF-STEM, and SEM-EDXS). The biomass was analyzed for its constituents in order to get a reliable estimate of its energy content, which is essential for the calculation of the process economics. The lower heating value of concentrated swine manure was found to be 16.3 MJ/kg{sub dry} {sub matter}. Skeletal nickel catalysts, which are widely used in the industry due to their attractive price, gasified wood suspensions (conc. 10 - 30 wt %) in a batch reactor completely to SNG. The methane yield was 0.33 g{sub CH{sub 4}}/ g{sub wood,} {sub dry}, which corresponds to the maximum yield governed by thermodynamics. Manure suspensions were also gasified in the hydrothermal environment. The highest methane yield achieved was only 0.21 g{sub CH{sub 4}}/ g{sub dry,} {sub matter}, which is 80% of the maximum yield by thermodynamics. The reason for this were the salts present in the manure, which had not been separated before the experiments and caused the deactivation of the catalyst. Thus, the importance of an integrated salt separator in a demonstration plant cannot be emphasized enough. The most promising catalyst systems (nickel, ruthenium) were tested for their activity and stability in the hydrothermal environment in a continuously operating test rig, where due to the applied pump only liquids could be fed. A mixture of five organic substances (formic and acetic acid, ethanol

  7. Continuous production of palm biofuel under supercritical ethyl acetate

    International Nuclear Information System (INIS)

    Komintarachat, Cholada; Sawangkeaw, Ruengwit; Ngamprasertsith, Somkiat

    2015-01-01

    Highlights: • Continuous synthesized biofuel from palm oil in supercritical ethyl acetate was examined. • Mass flow rate of palm oil and ethyl acetate mixture influent to biofuel production in continuous system. • Water addition to reacting mixture improves the production of fatty acid ethyl esters and triacetin. • The generated acetic acid from ETA hydrolysis can protect the products from thermal decomposition. - Abstract: The interesterification of palm oil in supercritical ethyl acetate (ETA) to produce fatty acid ethyl ester (FAEEs) or biofuel was conducted in a continuous tubular reactor. The density of the mixtures in the system was estimated using the Peng–Robinson equation of state process simulator, and the residence time was calculated. The effects of the reaction conditions, including the molar ratios of palm oil to ethyl acetate, the temperature, and the pressure, were investigated under various mass flow rates of the mixtures and optimized. The results showed that reaction temperatures above 653 K and long residence times affected the content of FAEEs and triacetin, a valuable by-product. The addition of water to the mixture in a 1:30:10 M ratio of palm oil to ethyl acetate to water at 653 K, 16 MPa, and a mixture mass flow rate of 1.5 g/min increased the total production of FAEEs and triacetin from 90.9 to 101.5 wt% in 42.4 min. The main finding of the present study is that triglyceride associated with ETA hydrolysis used to form acetic acid protected the products from decomposition at high temperatures and long residence times. The results will aid the selection of an efficient and economical process for alternative biofuel production from palm oil in supercritical ETA

  8. The sensitizing potential of primary amyl acetate in the guinea pig.

    Science.gov (United States)

    Ballantyne, B; Tyler, T R; Auletta, C S

    1986-06-01

    Primary amyl acetate is a liquid mixture of the isomeric forms of pentyl acetate, which is used as a volatile organic solvent. Because of the possibility for skin contact, primary amyl acetate was investigated for its potential to cause allergic contact dermatitis. Using a guinea pig maximization procedure, primary amyl acetate was found to be a possible marginal skin sensitizer.

  9. 21 CFR 862.1390 - 5-Hydroxyindole acetic acid/serotonin test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false 5-Hydroxyindole acetic acid/serotonin test system... Test Systems § 862.1390 5-Hydroxyindole acetic acid/serotonin test system. (a) Identification. A 5-hydroxyindole acetic acid/serotonin test system is a device intended to measure 5-hydroxyindole acetic acid...

  10. Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

    Directory of Open Access Journals (Sweden)

    Mansoor Anbia

    2016-06-01

    Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

  11. The Distribution of Hydrothermal Venting on Ultraslow Spreading Ridges

    Science.gov (United States)

    Baker, E. T.; Edmonds, H. N.; German, C. R.; Bach, W.; Banerjee, N. R.; Walker, S. L.

    2002-12-01

    Modeling efforts and field observations over the last decade have concluded that the thermal structure of midocean ridges (MORs) represents a balance between the supply of magmatic heat and the efficiency of cooling by hydrothermal circulation. A simple hypothesis states that the spatial density of hydrothermal circulation increases with the magma budget, but complicating factors include the role of permeability, heat sources other than magma, time-scale differences between venting and magma delivery/cooling, the uncertainty of vent-field exploration, and others. One of the most intriguing areas of hydrothermal research is ultraslow (spreading centers. These ridges compose ~25% of the global MOR system and are believed to have a much lower magma supply rate than would be predicted by a simple spreading-rate extrapolation. Is convective hydrothermal cooling proportionally lower as well? Recent plume-mapping surveys along more than 950 km of the Gakkel Ridge (GR) and 1300 km in two areas of the South West Indian Ridge (SWIR: 10° - 24° E and 58° - 66° E) have provided a first look at hydrothermal activity along ultraslow-spreading MORs. Hydrothermal plumes in all three of these regions have been detected almost exclusively using optical/temperature sensors, though corroborating chemical data exist for several sites on the GR. Plumes were rare on the SWIR, suggesting 8-15 active sites. In sharp contrast, >80% of 138 vertical profiles on the GR detected a plume, though these likely emanate from a minimum of 8-12 individual sites. Apparently the unusual hydrography of the deep Arctic Ocean combined with the simple geometry and deep rift valley of the GR promotes along-axis plume dispersal on a scale unseen elsewhere. Viewed on the global scale, and based on this limited data set, active venting per kilometer of axis length is substantially sparser on the SWIR and GR than on faster spreading ridges. Proportional to the magma delivery rate, however, venting appears to

  12. Hydrothermal fluoride and chloride complexation of indium: an EXAFS study

    Science.gov (United States)

    Loges, Anselm; Testemale, Denis; Huotari, Simo; Honkanen, Ari-Pekka; Potapkin, Vasily; Wagner, Thomas

    2017-04-01

    Indium (In) is one of the geochemically lesser studied ore metals, and the factors that control the hydrothermal transport and deposition are largely unknown. It has no ore deposits of its own and is commonly mined as a by-product of Zn ores, and there are very few minerals that contain In as an essential structural component. Recently, industrial application of In in touch screen devices has drastically increased demand, which is projected to exceed supply from the current sources in the near future. Since the most relevant In sources are hydrothermal sphalerite ores and to a lesser extent hydrothermal greisen-type deposits in evolved granitic plutons, the aqueous geochemistry of In is of particular interest for understanding its ore forming processes. As a first step towards a comprehensive model for hydrothermal In solubility and speciation, we have studied In speciation in fluoride and chloride bearing solutions at 30-400˚ C and 500 bar using X-Ray Absorption Spectroscopy (XAS) measurements. The experiments were conducted in a unique hydrothermal autoclave setup at beamline BM30B-FAME at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Our results show that the complexation of In changes dramatically between 30 and 400˚ C. Below ca. 200˚ C, fluoride complexes are the most stable ones, but they break down at higher temperatures. Chloride complexes on the other hand become increasingly stable with increasing temperature. This behavior has interesting consequences for natural ore forming systems. In Cl-rich systems (e.g. massive sulfide ores formed in sea floor environments), cooling can be an effective precipitating mechanism. In F-rich systems, fluoride complexation can extend In mobility to low temperatures and In will only precipitate when F is effectively removed from the fluid, e.g. by mixing with a Ca-rich fluid and precipitation of fluorite (CaF2) as is commonly observed in skarn or greisen-type deposits. Due to In complexing with

  13. V isotope composition in modern marine hydrothermal sediments

    Science.gov (United States)

    Wu, F.; Owens, J. D.; Nielsen, S.; German, C. R.; Rachel, M.

    2017-12-01

    Vanadium is multivalence transition metal with two isotopes (51V and 50V). Recent work has shown that large V isotope variations occur with oxygen variations in modern sediments (Wu et al., 2016 and 2017 Goldschmidt Abstracts), providing its potential as a promising proxy for determining low oxygen conditions. However, the development of V isotopes as a proxy to probe past redox conditions requires a comprehensive understanding of the modern oceanic isotopic mass balance. Therein, the scavenging of V from the hydrous iron oxides in hydrothermal fluid has been shown to be an important removal process from seawater (Rudnicki and Elderfield, 1993 GCA) but remains unquantified. In this study, we analyzed V isotopic compositions of metalliferous sediments around the active TAG hydrothermal mound from the mid-Atlantic Ridge (26° degrees North) and the Eastern Pacific Zonal Transect (GEOTRACES EPZT cruise GP16). The TAG sediments deposited as Fe oxyhydroxides from plume fall-out, and have δ51V values between -0.3 to 0‰. The good correlation between Fe and V for these metalliferous sediments indicate that the accumulation of V in these samples is directly related to the deposition of Fe oxyhydroxides, which also control their V isotope signature. The EPZT samples cover 8,000 km in the South Pacific Ocean with sedimentary areas that underlie the Peru upwelling region and the well-oxygenated deep South Pacific Ocean influenced by hydtorthermal plume material from southern East Pacific Rise (EPR). The sediments collected at the east of the EPR have δ51V values between -1.2 to -0.7‰, similar to previous δ51V of oxic sediments. In contrast, the sediments from the west of the EPR have δ51V values (-0.4 to 0‰) similar to hydrothermal sediments from the mid-Atlantic Ridge, indicating the long transportation (more than 4,000 km, Fitzsimmons et al., 2017 NG) of Fe and Mn from hydrothermal plume and their incorporation into sediments have a major impact on the cycle of V

  14. Highly sensitive avoidance plays a key role in sensory adaptation to deep-sea hydrothermal vent environments.

    Directory of Open Access Journals (Sweden)

    Tetsuya Ogino

    Full Text Available The environments around deep-sea hydrothermal vents are very harsh conditions for organisms due to the possibility of exposure to highly toxic compounds and extremely hot venting there. Despite such extreme environments, some indigenous species have thrived there. Alvinellid worms (Annelida are among the organisms best adapted to high-temperature and oxidatively stressful venting regions. Although intensive studies of the adaptation of these worms to the environments of hydrothermal vents have been made, little is known about the worms' sensory adaptation to the severe chemical conditions there. To examine the sensitivity of the vent-endemic worm Paralvinella hessleri to low pH and oxidative stress, we determined the concentration of acetic acid and hydrogen peroxide that induced avoidance behavior of this worm, and compared these concentrations to those obtained for related species inhabiting intertidal zones, Thelepus sp. The concentrations of the chemicals that induced avoidance behavior of P. hessleri were 10-100 times lower than those for Thelepus sp. To identify the receptors for these chemicals, chemical avoidance tests were performed with the addition of ruthenium red, a blocker of transient receptor potential (TRP channels. This treatment suppressed the chemical avoidance behavior of P. hessleri, which suggests that TRP channels are involved in the chemical avoidance behavior of this species. Our results revealed for the first time hypersensitive detection systems for acid and for oxidative stress in the vent-endemic worm P. hessleri, possibly mediated by TRP channels, suggesting that such sensory systems may have facilitated the adaptation of this organism to harsh vent environments.

  15. (Conversion of acetic acid to methane by thermophiles: Progress report)

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.

    1991-01-01

    The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

  16. [Conversion of acetic acid to methane by thermophiles: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.

    1991-12-31

    The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

  17. Leuprorelin Acetate in Prostate Cancer: a European Update

    Directory of Open Access Journals (Sweden)

    Persad R

    2002-01-01

    Full Text Available This review provides an update on leuprorelin acetate, the world's most widely prescribed depot luteinising hormone-releasing hormone analogue. Leuprorelin acetate has been in clinical use in the palliative treatment of prostate cancer for more than 20 years, but advances continue to be made in terms of convenience and flexibility of administration, and in the incorporation of leuprorelin acetate into novel treatment regimens. The drug is administered in the form of a depot injection containing leuprorelin acetate microspheres, and is at least as effective in suppressing testosterone secretion as orchiectomy. In patients with prostate cancer, serum testosterone levels are reduced to castrate levels (= 50 ng/dl within 2-3 weeks of the first one-month depot injection of 3.75 mg or three-month depot injection of 11.25 mg. Both the one-month and three-month formulations are effective in delaying tumour progression and alleviating symptoms of locally advanced and metastatic prostate cancer. Tolerability is generally good, with side-effects reflecting effective testosterone suppression. Recent studies have investigated the place of leuprorelin acetate as part of continuous or intermittent maximal androgen blockade (MAB and in neoadjuvant therapy (ie, to reduce the size of the prostate and downsize the tumour before radiotherapy. Additional formulations and presentations are in development, including a six-month injection, with the aim of adding to the clinical flexibility and patient acceptability of this important palliative treatment for prostate cancer.

  18. Alcohols enhance the rate of acetic acid diffusion inS. cerevisiae: biophysical mechanisms and implications for acetic acid tolerance.

    Science.gov (United States)

    Lindahl, Lina; Genheden, Samuel; Faria-Oliveira, Fábio; Allard, Stefan; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2017-12-01

    Microbial cell factories with the ability to maintain high productivity in the presence of weak organic acids, such as acetic acid, are required in many industrial processes. For example, fermentation media derived from lignocellulosic biomass are rich in acetic acid and other weak acids. The rate of diffusional entry of acetic acid is one parameter determining the ability of microorganisms to tolerance the acid. The present study demonstrates that the rate of acetic acid diffusion in S. cerevisiae is strongly affected by the alcohols ethanol and n-butanol. Ethanol of 40 g/L and n-butanol of 8 g/L both caused a 65% increase in the rate of acetic acid diffusion, and higher alcohol concentrations caused even greater increases. Molecular dynamics simulations of membrane dynamics in the presence of alcohols demonstrated that the partitioning of alcohols to the head group region of the lipid bilayer causes a considerable increase in the membrane area, together with reduced membrane thickness and lipid order. These changes in physiochemical membrane properties lead to an increased number of water molecules in the membrane interior, providing biophysical mechanisms for the alcohol-induced increase in acetic acid diffusion rate. n-butanol affected S. cerevisiae and the cell membrane properties at lower concentrations than ethanol, due to greater and deeper partitioning in the membrane. This study demonstrates that the rate of acetic acid diffusion can be strongly affected by compounds that partition into the cell membrane, and highlights the need for considering interaction effects between compounds in the design of microbial processes.

  19. Alcohols enhance the rate of acetic acid diffusion in S. cerevisiae: biophysical mechanisms and implications for acetic acid tolerance

    Science.gov (United States)

    Lindahl, Lina; Genheden, Samuel; Faria-Oliveira, Fábio; Allard, Stefan; Eriksson, Leif A.; Olsson, Lisbeth; Bettiga, Maurizio

    2017-01-01

    Microbial cell factories with the ability to maintain high productivity in the presence of weak organic acids, such as acetic acid, are required in many industrial processes. For example, fermentation media derived from lignocellulosic biomass are rich in acetic acid and other weak acids. The rate of diffusional entry of acetic acid is one parameter determining the ability of microorganisms to tolerance the acid. The present study demonstrates that the rate of acetic acid diffusion in S. cerevisiae is strongly affected by the alcohols ethanol and n-butanol. Ethanol of 40 g/L and n-butanol of 8 g/L both caused a 65% increase in the rate of acetic acid diffusion, and higher alcohol concentrations caused even greater increases. Molecular dynamics simulations of membrane dynamics in the presence of alcohols demonstrated that the partitioning of alcohols to the head group region of the lipid bilayer causes a considerable increase in the membrane area, together with reduced membrane thickness and lipid order. These changes in physiochemical membrane properties lead to an increased number of water molecules in the membrane interior, providing biophysical mechanisms for the alcohol-induced increase in acetic acid diffusion rate. n-butanol affected S. cerevisiae and the cell membrane properties at lower concentrations than ethanol, due to greater and deeper partitioning in the membrane. This study demonstrates that the rate of acetic acid diffusion can be strongly affected by compounds that partition into the cell membrane, and highlights the need for considering interaction effects between compounds in the design of microbial processes. PMID:29354649

  20. Study on the Reduction of Acetic Acid from Cabinets for Microfilms

    OpenAIRE

    佐野, 千絵; 古田嶋, 智子; 井上, さやか; 津田, 徹英; 呂, 俊民

    2012-01-01

    Concentration of acetic acid in cabinets, film storage and adjacent room were measured. Two cabinets were filled with acetic acid generated from aged microfilms. Absorbents were placed in one of the cabinets to remove acetic acid. It was confirmed thatconcentration of acetic acid decreased one week after setting the absorbents. Concentration in the other cabinet in which acetic-acid-absorbents were not placed remained high. From this result, it may be said that the absorbents were effective i...

  1. Hydrothermal Conversion of Neutral Sulfite Semi-Chemical Red Liquor into Hydrochar

    Directory of Open Access Journals (Sweden)

    Ramy Gamgoum

    2016-06-01

    Full Text Available Hydrochar was produced from neutral sulfite semi-chemical (NSSC red liquor as a possible bio-based solid fuel for use in power generation facilities. Hydrothermal conversion (HTC experiments were conducted using a fixed liquor-to-water volume ratio of 1:8 and reaction time of 3 h. Solutions were processed using different chemical additives, pH and temperature conditions to determine the optimum conditions required for producing a high energy content solid fuel. The hydrochar samples produced were analyzed by ultimate, thermogravimetric (TGA and Fourier transform infrared spectroscopy (FTIR analyses to determine physicochemical properties that are important for utilization as a fuel. The residual process liquids were also analyzed to better understand the effect of HTC process conditions on their properties. It was determined that the optimum conditions for producing a solid fuel was at a reaction temperature of 250 °C, in the presence of acetic acid at pH 3. The maximum energy content (HHV of the hydrochar produced from red liquor at this condition was 29.87 MJ/kg, and its ash content was 1.12 wt.%. This result reflects the effect of increasing reaction temperature on the physicochemical characteristics of the hydrochar. The increase of HTC temperature significantly reduces the ash content of the hydrochar, leads to a significant increase in the carbon content of the hydrochar, and a reduction in both the oxygen and hydrogen content. These effects suggests an increase in the degree of condensation of the hydrochar products, and consequently the formation of a high energy content material. Based on TGA and FTIR analyses, hydrochars prepared at high HTC temperature showed lower adsorbed moisture, hemicellulose and cellulose contents, with enrichment in content of higher temperature volatiles, such as lignin.

  2. Demineralization of Sargassum spp. macroalgae biomass: selective hydrothermal liquefaction process for bio-oil production

    Directory of Open Access Journals (Sweden)

    Liz M Díaz-Vázquez

    2015-02-01

    Full Text Available Algae biomasses are considered a viable option for the production of biofuel because of their high yields of oil produced per dry weight. Brown macroalgae Sargassum spp. are one of the most abundant species of algae in the shores of Puerto Rico. Its availability in large quantity presents a great opportunity for use as a source of renewable energy. However, high ash content of macroalgae affects the conversion processes and the quality of resulting fuel products. This research studied the effect of different demineralization treatments of Sargassum spp. biomass, subsequent hydrothermal liquefaction (HTL and bio-oil characterization. Demineralization constituted five different treatments: nanopure water, nitric acid, citric acid, sulfuric acid, and acetic acid. Performance of demineralization was evaluated by analyzing both demineralized biomass and HTL products by the following analyses: total carbohydrates, proteins, lipids, ash content, caloric content, metals analysis, Fourier Transform Infrared - Attenuated Total Reflectance (FTIR-ATR Spectroscopy, Energy Dispersive Spectroscopy (EDS, Scanning Electron Microscopy (SEM, and GCMS analysis. HTL of Sargassum spp. before and after citric acid treatment, was performed in a 1.8 L batch reactor system at 350°C with a holding time of 60 min and high pressures (5-21 MPa. Demineralization treatment with nitric acid was found the most effective in reducing the ash content of the macroalgae biomass from 27.46% to 0.99% followed by citric acid treatment that could reduce the ash content to 7%. Citric acid did not show significant leaching of organic components such as carbohydrates and proteins, and represented a less toxic and hazardous option for demineralization. HTL of untreated and citric acid treated Sargassum spp. resulted in bio-oil yields of 18.4±0.1 % and 22.2±0.1 % (ash free dry basis, respectively.

  3. Ethanol production from hydrothermal pretreated corn stover with a loop reactor

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda [National Lab for Sustainable Energy, Biosystems Department, Risoe-DTU, P.O. Box 49, DK-4000 Roskilde (Denmark)

    2010-03-15

    Hydrothermal pretreatment on raw corn stover (RCS) with a loop reactor was investigated at 195 C for different times varying between 10 min and 30 min. After pretreatment, the slurry was separated into water-insoluble solid (WIS) and liquid phase. Glucan and xylan were found in the both phases. The pretreatment condition showed a significant impact on xylan recovery. As the pretreatment time prolonged from 10 min to 30 min, the xylan recovery from liquid phase changed between 39.5% and 45.6% and the total xylan recoveries decreased from 84.7% to 61.6%. While the glucan recovery seemed not sensitive to the different pretreatment times. The glucan recovered from liquid was from 4.9% to 5.6% and the total glucan recoveries from all the pretreatments were higher than 98%. Besides HMF and furfural, acetic, lactic, formic and glycolic acids were also found in the liquid phase. All the concentrations of these potential inhibitors were lower enough not to affect the activity of the Saccharomyces cerevisiae (S. cerevisiae). Compared with the ethanol production of 32.4% from the RCS with S. cerevisiae, all the WISs gave higher ethanol productions ranging between 61.2% and 71.2%. When the xylan was taken into consideration, the best pretreatment condition would be 195 C, 15 min and the estimated total ethanol production was 201 g kg{sup -1} RCS by assuming the fermentation of both C-6 and C-5 with the ethanol yield of 0.51 g g{sup -1} and 0.47 g g{sup -1}, respectively. (author)

  4. Design and optimization of hydrogen production from hydrothermally pretreated sugarcane bagasse using response surface methodology.

    Science.gov (United States)

    Soares, Lais Américo; Braga, Juliana Kawanishi; Motteran, Fabrício; Sakamoto, Isabel Kimiko; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

    2017-07-01

    Hydrogen production from hydrothermally pretreated (200 °C for 10 min at 16 bar) sugarcane bagasse was analyzed using response surface methodology. The yeast extract concentration and the temperature had a significant influence for hydrogen production (p-value 0.027 and 0.009, respectively). Maximum hydrogen production (17.7 mmol/L) was observed with 3 g/L yeast extract at 60 °C (C10). In this conditions were produced acetic acid (50.44 mg/L), butyric acid (209.71 mg/L), ethanol (38.4 mg/L), and methane (6.27 mmol/L). Lower hydrogen productions (3.5 mmol/L and 3.9 mmol/L) were observed under the conditions C7 (2 g/L of yeast extract, 35.8 °C) and C9 (1 g/L of yeast extract, 40 °C), respectively. The low yeast extract concentration and low temperature caused a negative effect on the hydrogen production. By means of denaturing gradient gel electrophoresis 20% of similarity was observed between the archaeal population of mesophilic (35 and 40 °C) and thermophilic (50, 60 and 64 °C) reactors. Likewise, similarity of 22% was noted between the bacterial population for the reactors with the lowest hydrogen production (3.5 mmol/L), at 35.8 °C and with the highest hydrogen production (17.7 mmol/L) at 60 °C demonstrating that microbial population modification was a function of incubation temperature variation.

  5. Characterization of differently sized granule fractions of yellow pea, cowpea and chickpea starches after modification with acetic anhydride and vinyl acetate

    NARCIS (Netherlands)

    Huang, J.; Schols, H.A.; Jin, Z.; Sulmann, E.; Voragen, A.G.J.

    2007-01-01

    The effect of reagent type on the properties of acetylated starches was studied for yellow pea, cowpea and chickpea starches after modification with acetic anhydride and vinyl acetate. Samples modified with vinyl acetate showed higher swelling volume and peak viscosity than those acetylated with

  6. Hydrothermal Habitats: Measurements of Bulk Microbial Elemental Composition, and Models of Hydrothermal Influences on the Evolution of Dwarf Planets

    Science.gov (United States)

    Neveu, Marc Francois Laurent

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life. Such environments include hydrothermal systems, spatially-confined systems where hot aqueous fluid circulates through rock by convection. I sought to characterize hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA, by measuring their bulk elemental composition. To do so, one must minimize the contribution of non-biological material to the samples analyzed. I demonstrate that this can be achieved using a separation method that takes advantage of the density contrast between cells and sediment and preserves cellular elemental contents. Using this method, I show that in spite of the tremendous physical, chemical, and taxonomic diversity of Yellowstone hot springs, the composition of microorganisms there is surprisingly ordinary. This suggests the existence of a stoichiometric envelope common to all life as we know it. Thus, future planetary investigations could use elemental fingerprints to assess the astrobiological potential of hydrothermal settings beyond Earth. Indeed, hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core. I enhance a dwarf planet evolution code, including the effects of core fracturing and hydrothermal circulation, to demonstrate that dwarf planets likely have undergone extensive water-rock interaction. This supports observations of aqueous products on their surfaces. I simulate the alteration of chondritic rock by pure water or cometary fluid to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the

  7. Hydrothermal carbonization: process water characterization and effects of water recirculation.

    Science.gov (United States)

    Stemann, Jan; Putschew, Anke; Ziegler, Felix

    2013-09-01

    Poplar wood chips were treated hydrothermally and the increase of process efficiency by water recirculation was examined. About 15% of the carbon in the biomass was dissolved in the liquid phase when biomass was treated in de-ionized water at 220 °C for 4 h. The dissolved organic matter contained oxygen and was partly aerobically biodegradable. About 30-50% of the total organic carbon originated from organic acids. A polar and aromatic fraction was extracted and a major portion of the organic load was of higher molecular weight. By process water recirculation organic acids in the liquid phase concentrated and catalyzed dehydration reactions. As a consequence, functional groups in hydrothermally synthesized coal declined and dewaterability was enhanced. Recirculated reactive substances polymerized and formed additional solid substance. As a result, carbon and energetic yields of the produced coal rose to 84% and 82%, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. The Detailed Evolution of Carbon Spheres by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Trevor Mwenya

    2016-01-01

    Full Text Available Carbon spheres (CSs can be synthesized easily by hydrothermal method using various solutions and a lot of mechanisms have been employed to explain their formation. In our work, some special phenomena such as the uniform size and surface corruption have been found as the reaction time increased. However, less attention has been focused on the detailed evolution phenomena of CSs. In order to understand these special phenomena well, classical nucleation theory was employed to study the reaction dynamics of CSs during the evolution processes. This work not only deeply reveals the evolution mechanism of CSs, but also opens a possible way for the control of size and morphologies of CSs through hydrothermal methods.

  9. Hydrothermal synthesis and physicochemical properties of ruthenium(0) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dikhtiarenko, A., E-mail: dikhtiarenkoalla@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Khainakov, S.A.; Garcia, J.R.; Gimeno, J. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Pedro, I. de; Fernandez, J. Rodriguez [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Ruthenium nanoparticles were synthesized by hydrothermal technique. Black-Right-Pointing-Pointer The average size of the nanoparticles are depend on the reducing agent used. Black-Right-Pointing-Pointer The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the ruthenium(0) nanoparticles. - Abstract: The synthesis of ruthenium nanoparticles in hydrothermal conditions using mild reducing agents (succinic acid, ascorbic acid and sodium citrate) is reported. The shape of the nanoparticles depends on the type of the reducing agent, while the size is more influenced by the pH of the medium. The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the nanoparticles.

  10. Obtaining zeolite Y synthesized by hydrothermal treatment assisted by microwave

    International Nuclear Information System (INIS)

    Simoes, A.N.; Simoes, V.N.; Neiva, L.S.; Rodrigues, M.G.F.; Gama, L.; Oliveira, J. B.L.

    2011-01-01

    n search of new catalysts several man-made structures have been developed. The use of zeolites in catalysis is applied due to its ability to associate activity, selectivity and stability, the main conditions to have an effective catalyst. Thus, studies have been done on the hydrothermal synthesis of zeolites by microwave assisted, since the use of microwave radiation offers several advantages over conventional heating. In this context, this work aims to synthesis and characterization of zeolite Y via hydrothermal treatment in a microwave oven. The sample obtained was characterized by XRD, BET and SEM. XRD results showed the formation of zeolite Y in just 60 minutes. The sample showed high value of surface area, the latter being of 476.2 m² / g. The particles are agglomerated, but with a narrow distribution of size. (author)

  11. Colorado's hydrothermal resource base: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Pearl, R.H.

    1981-01-01

    As part of its effort to more accurately describe the nations geothrmal resource potential, the US Department of Energy/Division of Geothermal Energy contracted with the Colorado Geological survey to appraise the hydrothermal (hot water) geothermal resources of Colorado. Part of this effort required that the amount of energy that could possibly be contained in the various hydrothermal systems in Colorado be estimated. The findings of that assessment are presented. To make these estimates the geothermometer reservoir temperatures estimated by Barrett and Pearl (1978) were used. In addition, the possible reservoir size and extent were estimated and used. This assessment shows that the total energy content of the thermal systems in Colorado could range from 4.872 x 10{sup 15} BTU's to 13.2386 x 10{sup 15} BTU's.

  12. Self-excited hydrothermal waves in evaporating sessile drops

    Science.gov (United States)

    Sefiane, K.; Moffat, J. R.; Matar, O. K.; Craster, R. V.

    2008-08-01

    Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC-72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrothermal waves have been observed in the absence of evaporation in shallow liquid layers subjected to an imposed temperature gradient. In contrast, here both the temperature gradients and the drop thickness vary spatially and temporally and are a natural consequence of the evaporation process.

  13. Tectonic and Hydrothermal Activities in Debagh, Guelma Basin (Algeria

    Directory of Open Access Journals (Sweden)

    Said Maouche

    2013-01-01

    Full Text Available Quaternary and Pliocene travertines, deposited from hot springs, can reveal much about neotectonic and hydrothermal activity. The aim of this work is the understanding of the actual tectonic activity in the Guelma Basin and in one of its spa structures. Gravity data were collected during a field study in the Hammam Debagh (HD area and then analyzed to better highlight the architecture of its subsurface underlying structures. This analysis was performed by means of a Bouguer anomaly, upward continuations, and residual and derivative maps. Comparison of gravity maps, field geology, geomorphic observations, and structural maps allowed us to identify the major structural features in the Hammam Debagh. As a result, we confirm the position of the Hammam Debagh active fault which is superimposed to the hydrothermal active source in the NW-SE direction characterized by a negative gravity anomaly.

  14. Acoustics advances study of sea floor hydrothermal flow

    Science.gov (United States)

    Rona, Peter A.; Jackson, Darrell R.; Bemis, Karen G.; Jones, Christopher D.; Mitsuzawa, Kyohiko; Palmer, David R.; Silver, Deborah

    Sub-sea floor hydrothermal convection systems discharge as plumes from point sources and as seepage from the ocean bottom. The plumes originate as clear, 150-400°C solutions that vent from mineralized chimneys; precipitate dissolved metals as particles to form black or white smokers as they turbulently mix with ambient seawater; and buoyantly rise hundreds of meters to a level of neutral density where they spread laterally. The seepage discharges from networks of fractures at the rock-water interface as clear, diffuse flow, with lower temperatures, metal contents, and buoyancy than the smokers. The diffuse flow may be entrained upward into plumes, or laterally by prevailing currents in discrete layers within tens of meters of the sea floor. The role of these flow regimes in dispersing heat, chemicals, and biological material into the ocean from sub-sea floor hydrothermal convection systems is being studied on a global scale.

  15. Isotopic study of some fossil and actual hydrothermal systems

    International Nuclear Information System (INIS)

    Demont, J.M.

    1981-07-01

    Oxygen and hydrogen isotopic compositions of rocks from the INAG no 1 drillhole provide evidence of a fossil hydrothermal system in the Ceyssat region of the Massif Central. Oxygen isotope temperatures for the mineral paragenesis are about 275 0 C and the water is of marine origin. Measurements have also been made of delta 13 C values of dissolved carbon and gaseous CO 2 from several hot springs in the Pyrenees and Massif Central. The carbon isotopic composition of the total systems have been calculated from the gas-liquid ratios at the emergence sites and these results are discussed in terms of the origin of the carbon. Most of the hydrothermal carbon is of deep origin. The observed variations in isotopic compositions may be explained by the behavior of the fluids during their ascent to the surface [fr

  16. Hydrothermal Synthesis of Meso-porous Materials using Diatomaceous Earth

    Science.gov (United States)

    Jing, Z.; Kato, S.; Maeda, H.; Ishida, E. H.

    2007-03-01

    In order to sustain the inherent properties of diatomaceous earth (DE), a low-temperature synthesis of mesoporous material from DE was carried out using a hydrothermal processing technique under saturated steam pressure at 200 °C for 12 h. The experimental results showed that the most important strength-producing constituent in the solidified specimens was tobermorite formed by hydrothermal processing, and the addition of slaked lime was favorable to tobermorite formation. At Ca/Si ratio around 0.83 in the starting material, tobermorite appeared to form readily. A high autoclave curing temperature (200 °C), or a longer curing time (12 h) seemed to accelerate the tobermorite formation, thus leading to a higher strength development.

  17. Thermodynamic analysis of hydrogen production via hydrothermal gasification of hexadecane

    KAUST Repository

    Alshammari, Yousef M.

    2012-04-01

    This work reports the equilibrium behaviour of the hydrothermal gasification of hexadecane, a heavy saturate model compound, under non-oxidative isothermal and oxidative adiabatic conditions, using the Peng-Robinson equation of state and the direct minimisation of Gibbs free energy employed within the Aspen HYSYS. This modelling enabled establishing both the limits and optimum conditions at which the hydrogen molar yield may be theoretically maximised. The effects of parameters including the reactor isothermal temperature, pressure, water to carbon ratio, and oxygen to carbon ratio on the molar yields of produced gaseous species were analysed. The model has been validated by comparing its results with different reported modelling and experimental data under identical conditions which resulted in a good agreement. The results reported in this work show the potential of achieving economic yields of hydrogen and syngas from liquid hydrocarbons under downhole hydrothermal conditions. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

  18. [Conversion of acetic acid to methane by thermophiles

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

  19. Pulse radiolysis of ethyl acetate and its solutions

    International Nuclear Information System (INIS)

    Ramanan, G.

    1976-01-01

    Pure ethyl acetate was subjected to electron pulse radiolysis in the liquid state and the absorption spectrum of the transient species produced was obtained between 280 and 650 nm. Two different species were produced, one with a short life of about 150 ns absorbing at longer wavelengths attributed to the solvated electron and a much longer lived radical absorbing at wavelengths less than 400 nm. The solute triplet yields were followed using anthracene and biphenyl at different concentrations. An upperlimit for the yield of excited singlet anthracene was estimated from the study of fluorescence to be G approximately equal to 0.1. Anthracene singlet yields in the presence of benzene at different concentrations were measured and the contribution of ethyl acetate positive ions in forming the additional exicted singlets is discussed. The free ion yield is G = 0.25. Yield of ethyl acetate positive ions scavengeable at high benzene concentrations is G = 0.63

  20. Crystal structure of febuxostat–acetic acid (1/1

    Directory of Open Access Journals (Sweden)

    Min Wu

    2015-05-01

    Full Text Available The asymmetric unit of the title compound [systematic name: 2-(3-cyano-4-isobutyloxyphenyl-4-methylthiazole-5-carboxylic acid–acetic acid (1/1], C16H16N2O3S·CH3COOH, contains a febuxostat molecule and an acetic acid molecule. In the febuxostat molecule, the thiazole ring is nearly coplanar with the benzene ring [dihedral angle = 3.24 (2°]. In the crystal, the febuxostat and acetic acid molecules are linked by O—H...O, O—H...N hydrogen bonds and weak C—H...O hydrogen bonds, forming supramolecular chains propagating along the b-axis direction. π–π stacking is observed between nearly parallel thiazole and benzene rings of adjacent molecules; the centroid-to-centroid distances are 3.8064 (17 and 3.9296 (17 Å.

  1. Measurement of acetic acid using a fibre Bragg grating interferometer

    International Nuclear Information System (INIS)

    Jesus, C; Silva, S F O; Castanheira, M; GonzálezAguilar, G; Frazão, O; Jorge, P A S; Baptista, J M

    2009-01-01

    An optical fibre sensor for determination of acetic acid is presented. The sensing probe is based on a fibre Bragg grating (FBG) Fabry–Perot cavity, coated with a thin film of sol–gel–PVP (polyvinylpyrrolidone) composite material. The polymeric thin film renders the interferometric output sensitive to the presence of carboxylic acid species. Results show that the wavelength of the interferometric peaks changes with acetic acid concentration, enabling its quantification. Coupling the fibre probe with a serrodyne modulated readout interferometer enables pseudo-heterodyne interrogation and the detection of acetic acid with a sensitivity of 92.6 deg/% L/L and a resolution of 0.2% L/L. The results demonstrate the potential of the proposed scheme to operate as a sensitive chemical sensor platform

  2. Characterization of acetic acid bacteria in "traditional balsamic vinegar".

    Science.gov (United States)

    Gullo, Maria; Caggia, Cinzia; De Vero, Luciana; Giudici, Paolo

    2006-02-01

    This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with concentrated cooked must. On the contrary, ethanol concentration of the cooked and fermented must is less significant for acetic acid bacteria growth. A tentative identification of the isolated strains was done by 16S-23S-5S rDNA PCR/RFLP technique and the isolated strains were clustered: 32 strains belong to Gluconacetobacter xylinus group, two strains to Acetobacter pasteurianus group and one to Acetobacter aceti.

  3. Microbial anaerobic methane cycling in the subseafloor at the Von Damm hydrothermal vent field, Mid-Cayman Rise

    Science.gov (United States)

    Huber, J. A.; Reveillaud, J. C.; Stepanauskas, R.; McDermott, J. M.; Sylva, S. P.; Seewald, J.

    2013-12-01

    methanogenic archaea are also present, including the hyperthermophile Methanopyrus, as well as methanogens that can use acetate, methanol, and other simple carbon compounds for methane generation, such as the genera Methanosaeta and Methermicoccus. In addition, uncultivated lineages related to putative anaerobic methane cycling archaea were detected in the fluids. These include the GOM Arc I clade within the Methanosarcinales, a group previously described from Gulf of Mexico methane seeps and thought to be methanogenic, as well as the ANME-1 and ANME-2 lineages, which are likely anaerobically oxidizing methane. On-going metagenomic sequencing of both mixed microbial communities and single cells from venting fluids will reveal the genomic repertoire, evolutionary relationships, and adaptations of these unique methane-cycling anaerobic archaea in the subseafloor at the Von Damm hydrothermal vent field.

  4. Hydrothermal heat discharge in the Cascade Range, northwestern United States

    Science.gov (United States)

    Ingebritsen, S.E.; Mariner, R.H.

    2010-01-01

    Hydrothermal heat discharge in the Cascade Range includes the heat discharged by thermal springs, by "slightly thermal" springs that are only a few degrees warmer than ambient temperature, and by fumaroles. Thermal-spring heat discharge is calculated on the basis of chloride-flux measurements and geothermometer temperatures and totals ~ 240 MW in the U.S. part of the Cascade Range, excluding the transient post-1980 discharge at Mount St. Helens (~80 MW as of 2004-5). Heat discharge from "slightly thermal" springs is based on the degree of geothermal warming (after correction for gravitational potential energy effects) and totals ~. 660. MW. Fumarolic heat discharge is calculated by a variety of indirect and direct methods and totals ~160 MW, excluding the transient mid-1970s discharge at Mount Baker (~80 MW) and transient post-1980 discharge at Mount St. Helens (>. 230. MW as of 2005). Other than the pronounced transients at Mount St. Helens and Mount Baker, hydrothermal heat discharge in the Cascade Range appears to be fairly steady over a ~25-year period of measurement. Of the total of ~. 1050. MW of "steady" hydrothermal heat discharge identified in the U.S. part of the Cascade Range, less than 50. MW occurs north of latitude 45??15' N (~0.1 MW per km arc length from 45??15' to 49??N). Much greater rates of hydrothermal heat discharge south of 45??15'N (~1.7 MW per km arc length from 40?? to 45??15'N) may reflect the influence of Basin and Range-style extensional tectonics (faulting) that impinges on the Cascades as far north as Mount Jefferson but is not evident farther north. ?? 2010.

  5. Geochemical Constraints on Archaeal Diversity in the Vulcano Hydrothermal System

    Science.gov (United States)

    Rogers, K. L.; Amend, J. P.

    2006-12-01

    The shallow marine hydrothermal system of Vulcano, Italy hosts a wide diversity of cultured thermophilic Archaea, including Palaeococcus helgesonii, Archaeoglobus fulgidus, and Pyrococcus furiosus, to name a few. However, recent studies have revealed a plethora of uncultured archaeal lineages in the Vulcano system. For example, a 16S rRNA gene survey of an onshore geothermal well identified a diverse archaeal community including deeply-branching uncultured Crenarchaeota, Korarchaeota, and Euryarchaeota. Additionally, culture-independent hybridization techniques suggested that Archaea account for nearly half of the microbial community in the Vulcano system. Furthermore, geochemical characterization of fluids revealed numerous lithotrophic and heterotrophic exergonic reactions that could support as yet uncultured organisms. Archaeal diversity throughout the Vulcano hydrothermal system was investigated using 16S rRNA gene surveys at five submarine vents and an onshore sediment seep. Overall, archaeal diversity was higher (10 groups) at submarine vents with moderate temperatures (59°C) compared with higher temperature (94°C) vents (4 groups). Archaeal communities at the moderately thermal vents were dominated by Thermococcales and also contained Archaeoglobales, Thermoproteales, and uncultured archaea among the Korarchaeota, Marine Group I, and the Deep-sea Hydrothermal Vent Euryarchaeota (DHVE). Fluid composition also affects the microbial community structure. At two high-temperature sites variations in archaeal diversity can be attributed to differences in iron and hydrogen concentrations, and pH. Comparing sites with similar temperature and pH conditions suggests that the presence of Desulfurococcales is limited to sites at which metabolic energy yields exceed 10 kJ per mole of electrons transferred. The Vulcano hydrothermal system hosts diverse archaeal communities, containing both cultured and uncultured species, whose distribution appears to be constrained by

  6. Effect of hydrothermal treatment on light transmission of translucent zirconias.

    Science.gov (United States)

    Putra, Armand; Chung, Kwok-Hung; Flinn, Brian D; Kuykendall, Tuesday; Zheng, Cheng; Harada, Kosuke; Raigrodski, Ariel J

    2017-09-01

    Studies of the light transmission of translucent zirconias after hydrothermal treatment are limited. The purpose of this in vitro study was to evaluate the effect of hydrothermal treatment on the light transmission of translucent zirconias for monolithic restorations. Four commercially available zirconia products, BruxZir Anterior Solid Zirconia (BruxAnt, BA), Lava Plus High Translucency (LPHT), Katana Zirconia Super Translucent (KST), and Katana Zirconia Ultra Translucent (KUT) were assessed and 1 type of lithium disilicate, e.max Press LT (LDLT) was used as a control. Plate specimens, 20×20×1 mm (n=80) for the translucency assessment were sectioned from postsintered zirconia bulk materials and ground with a #400-grit diamond wheel and coolant. The specimens were placed under hydrothermal conditions of 134°C at 0.2 MPa (n=5 per group at 0, 5, 50, and 100 hours). Percentage of total transmittance of light (T t %) of each specimen was measured using a spectrophotometer with an integrating sphere. X-ray diffraction analyses were used to measure tetragonal-monoclinic phase transformation. Surfaces were examined by scanning electron microscopy and energy dispersive spectrometry. Data were analyzed using 2-way ANOVA followed by the Tukey test (α=.05). The T t % ranged from 6.5% to 28.3%. Group LDLT obtained significantly higher transmittance than other tested groups, whereas groups KST and KUT had significantly higher T t % than groups BA and LPHT (Phydrothermal treatment for all tested translucent zirconias and a lithium disilicate glass-ceramic control. Hydrothermal treatment had minimal effects on the translucency of translucent zirconias. The tetragonal-monoclinic phase transformation rate of translucent zirconias was found to be low, except in group LPHT. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing▿

    Science.gov (United States)

    Miyamoto, Toru; Okano, Shinya; Kasai, Noriyuki

    2009-01-01

    Bacterial endotoxins, also known as lipopolysaccharides, are a fever-producing by-product of gram-negative bacteria commonly known as pyrogens. It is essential to remove endotoxins from parenteral preparations since they have multiple injurious biological activities. Because of their strong heat resistance (e.g., requiring dry-heat sterilization at 250°C for 30 min) and the formation of various supramolecular aggregates, depyrogenation is more difficult than sterilization. We report here that soft hydrothermal processing, which has many advantages in safety and cost efficiency, is sufficient to assure complete depyrogenation by the inactivation of endotoxins. The endotoxin concentration in a sample was measured by using a chromogenic limulus method with an endotoxin-specific limulus reagent. The endotoxin concentration was calculated from a standard curve obtained using a serial dilution of a standard solution. We show that endotoxins were completely inactivated by soft hydrothermal processing at 130°C for 60 min or at 140°C for 30 min in the presence of a high steam saturation ratio or with a flow system. Moreover, it is easy to remove endotoxins from water by soft hydrothermal processing similarly at 130°C for 60 min or at 140°C for 30 min, without any requirement for ultrafiltration, nonselective adsorption with a hydrophobic adsorbent, or an anion exchanger. These findings indicate that soft hydrothermal processing, applied in the presence of a high steam saturation ratio or with a flow system, can inactivate endotoxins and may be useful for the depyrogenation of parenterals, including end products and medical devices that cannot be exposed to the high temperatures of dry heat treatments. PMID:19502435

  8. Self-excited hydrothermal waves in evaporating sessile drops

    OpenAIRE

    Sefiane K.; Moffat J.R.; Matar O.K.; Craster R.V.

    2008-01-01

    Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC- 72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrotherma...

  9. Tectonic and Hydrothermal Activities in Debagh, Guelma Basin (Algeria)

    OpenAIRE

    Maouche, Said; Abtout, Abdeslam; Merabet, Nacer-Eddine; Aïfa, Tahar; Lamali, Atmane; Bouyahiaoui, Boualem; Bougchiche, Sofiane; Ayache, Mohamed

    2013-01-01

    Quaternary and Pliocene travertines, deposited from hot springs, can reveal much about neotectonic and hydrothermal activity. The aim of this work is the understanding of the actual tectonic activity in the Guelma Basin and in one of its spa structures. Gravity data were collected during a field study in the Hammam Debagh (HD) area and then analyzed to better highlight the architecture of its subsurface underlying structures. This analysis was performed by means of a Bouguer anomaly, upward c...

  10. Hydrothermal system in Southern Grass Valley, Pershing County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Welch, A.H.; Sorey, M.L.; Olmsted, F.H.

    1981-01-01

    Southern Grass Valley is a fairly typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active hydrothermal flow system with an estimated deep aquifer temperature of 163 to 176/sup 0/C. Results of geologic, hydrologic, geophysical and geochemical investigations are discussed in an attempt to construct an internally consistent model of the system.

  11. Hydrothermal synthesis and characterization of zirconia based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Caillot, T., E-mail: Thierry.caillot@ircelyon.univ-lyon1.fr; Salama, Z.; Chanut, N.; Cadete Santos Aires, F.J.; Bennici, S.; Auroux, A.

    2013-07-15

    In this work, three equimolar mixed oxides ZrO{sub 2}/CeO{sub 2}, ZrO{sub 2}/TiO{sub 2}, ZrO{sub 2}/La{sub 2}O{sub 3} and a reference ZrO{sub 2} have been synthesized by hydrothermal method. The structural and surface properties of these materials have been fully characterized by X-ray diffraction, transmission electron microscopy, surface area measurement, chemical analysis, XPS, infrared spectroscopy after adsorption of pyridine and adsorption microcalorimetry of NH{sub 3} and SO{sub 2} probe molecules. All investigated mixed oxides are amphoteric and possess redox centers on their surface. Moreover, hydrothermal synthesis leads to catalysts with higher surface area and with better acid–base properties than classical coprecipitation method. Both Lewis and Brønsted acid sites are present on the surface of the mixed oxides. Compared to the other samples, the ZrO{sub 2}/TiO{sub 2} material appears to be the best candidate for further application in acid–base catalysis. - Graphical abstract: Mesoporous amorphous phase with a high surface area of titania zirconia mixed oxide obtained by hydrothermal preparation. - Highlights: • Three zirconia based catalysts and a reference were prepared by hydrothermal synthesis. • Mixed oxides present larger surface areas than the reference ZrO{sub 2}. • ZrO{sub 2}/TiO{sub 2} catalyst presents a mesoporous structure with high surface area. • ZrO{sub 2}/TiO{sub 2} catalyst presents simultaneously strong acidic and basic properties.

  12. Hydrothermal reactions of nuclear waste solids . A preliminary study

    International Nuclear Information System (INIS)

    Westsik, J.H. Jr.; Turcotte, R.P.

    1978-09-01

    A simulated high-level waste glass, Supercalcine, and some common ceramic and metallic solids were exposed to hydrothermal conditions at 250 and 350 0 C for time periods ranging from three days to three weeks. Most of the experiments were done in salt brine, but the glass study did include deionized water tests so that the influence of salt could be better understood. Under the extreme hydrothermal conditions of these tests, all of the materials examined underwent measurable changes. The glass is converted to a mixture of crystalline phases, depending upon conditions, giving NaFeSi 2 O 6 as the primary alteration product. The rate of alteration is higher in deionized water than in salt brine; however, under equivalent test conditions, 66% of the Cs originally in the glass is released to the salt brine, while only 6% is released to deionized water. Rb and Mo are the only other fission product elements significantly leached from the glass. Evidence is presented which shows that sintered Supercalcine undergoes chemical changes in salt brine that are qualitatively similar to those experienced by glass samples. High concentrations of Cs enter the aqueous phase, and Sn and Mo are mobilized. Scouting tests were made with a variety of materials including commercial glasses, granite, UO 2 , Al 2 O 3 , steel, and waste glasses. Weight losses under hydrothermal conditions are in a relatively narrow band, with glass and ceramic materials showing 3 to 20 times greater weight losses than 304L stainless steel in the 250 0 C test used. The conclusion from these studies is that virtually all solid materials show hydrothermal reactivity at temperatures between 250 and 350 0 C, and that these extreme conditions are not desirable

  13. The partitioning of uranium and neptunium onto hydrothermally altered concrete

    International Nuclear Information System (INIS)

    Zhao, P.; Allen, P.G.; Sylwester, E.R.; Viani, B.E.

    2000-01-01

    Partition coefficients (K d ) of U(VI) and Np(V) on untreated and hydrothermally altered concrete were measured in 0.01 M NaCl and 0.01 M NaHCO 3 solutions as functions of concentration of the radionuclides, pH, and time. The partition coefficients for both U(VI) and Np(V) on hydrothermally altered concrete are significantly lower than those on untreated concrete. The partition of both U(VI) and Np(V) are pH dependent, although the pH dependence does not appear to reflect precipitation of U and Np-bearing phases. Both sorption and precipitation are likely processes controlling partitioning of U to concrete; sorption is the most likely process controlling the partitioning of Np to concrete. The presence of 0.01 M carbonate species in solution decreases K d of U(VI) for both hydrothermally altered and untreated concrete from ≥ 10 4 mL/g to ∝ 400 to 1000 mL/g indicating a significant impact on U(VI) sorption. In contrast, the presence of carbonate only reduced the K d of Np(V) by one order of magnitude or less. X-ray absorption spectroscopy analysis of U/concrete mixtures at different pHs and times indicate that uranyl ions are partitioned as monomeric species on untreated concrete, but oligomeric species on hydrothermally altered concrete. Similar analysis of Np/concrete mixtures shows that about half of the partitioned Np(V) is reduced to Np(IV) over a period of 6 months. (orig.)

  14. Tailored super magnetic nanoparticles synthesized via template free hydrothermal technique

    Science.gov (United States)

    Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M. S. A.

    2016-01-01

    Magnetite nanoparticles of controlled shape and dimensions were synthesized using a modified hydrothermal technique. The influence of different synthesis conditions on the shape, size (length and diameter), structure and magnetic properties of the prepared nanoparticles is presented. The mineral phases, the morphologies, size distribution of the resulting magnetic nanoparticles and their magnetic properties were characterized using different characterization methods. We designed magnetite nanoparticles with different morphologies (nanospheres, nanorods, nanocubes and hexagons) and with improved saturation magnetization reaching 90 emu/g.

  15. Market Power Assessment and Mitigation in Hydrothermal Systems

    OpenAIRE

    Rafael Kelman; Luiz Barroso; Mario Pereira

    2005-01-01

    The objective of this work is to investigate market power issues in bid- based hydrothermal scheduling. Initially, market power is simulated with a single stage Nash-Cournot equilibrium model. Market power assessment for multiple stages is then carried through a stochastic dynamic programming scheme. The decision in each stage and state is the equilibrium of a multi-agent game. Thereafter, mitigation measures, specially bilateral contracts, are investigated. Case studies with data taken from ...

  16. High purity neodymium acetate from mixed rare earth carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A., E-mail: cqueiroz@ipen.b, E-mail: smrrocha@ipen.b, E-mail: mstela@ipen.b, E-mail: rmlobo@ipen.b, E-mail: jaseneda@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pedreira, Walter dos R., E-mail: walter.pedreira@fundacentro.gov.b [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Sao Paulo, SP (Brazil)

    2011-07-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd{sub 2}O{sub 3} in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in {mu}g g{sup -1}: Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

  17. Hydrothermal synthesis of magnetite particles with uncommon crystal facets

    Directory of Open Access Journals (Sweden)

    Junki Sato

    2014-09-01

    Full Text Available Hydrothermal synthesis of Fe3O4 (magnetite particles was carried out using organic compounds as morphology control agents to obtain magnetite crystals with uncommon facets. It was established that the morphology of Fe3O4 crystals obtained by hydrothermal treatment of an aqueous solution containing Fe2+ and organic compounds depended on the organic compound used. The shape of the Fe3O4 particles obtained when no additives were used was quasi-octahedral. In contrast, the addition of picolinic acid, citric acid or pyridine resulted in the formation of polyhedral crystals, indicating the presence of not only {1 1 1}, {1 0 0} and {1 1 0} facets but also high-index facets including at least {3 1 1} and {3 3 1}. When citric acid was used as an additive, octahedral crystals with {1 1 1} facets also appeared, and their size decreased as the amount of citric acid was increased. Thus, control of Fe3O4 particle morphology was achieved by a simple hydrothermal treatment using additives.

  18. Hydrothermal alteration in Dumoga Barat, Bolaang Mongondow area North Sulawesi

    International Nuclear Information System (INIS)

    Agus Harjanto' Sutanto; Sutarto; Achmad Subandrio; I Made Suasta; Juanito Salamat; Giri Hartono; Putu Suputra; I Gde Basten; Muhammad Fauzi; Rosdiana

    2016-01-01

    Bolaang Mongondow is located in central north Sulawesi arm, which is composed of Neogen magmatic arc and potentially contain economic minerals. This condition is behind the research purpose to study the mineral resources potencies. Research aim is to study alteration caused by hydrothermal process and its relation with gold (Au) deposit based on field study and laboratory analysis. Methodologies used for the research are literature study, geological survey, rocks sampling, laboratory analysis, and data processing. Research area is a multiply diorite intrusion complex. Andesite, volcaniclastic rocks, and dacite, the older rocks, were intruded by this complex. Later, dacitic tuff, volcanic sandstone, and alluvium deposited above them. There are three measured and mapped major faults heading NE-SW crossed by E-W fault and NW-SE fault lately crossed all the older faults. Early stage hydrothermal alteration related to the existence of young quartz diorite, showing alteration stage from the potassic center to distal prophylatic. Final stage hydrothermal alteration consist of argilic, advanced argilic, and silica-clay mineral±magnetite±chlorite alteration overlapping the earlier alteration. Mineralization of Cu-Au±Ag in central part of research area or Tayap-Kinomaligan area is mostly associated with potassic altered young quartz diorite and crossed by parallel and stock worked quartz-magnetite-chalcopyrite±bornite vein. (author)

  19. Primary Formation Path of Formaldehyde in Hydrothermal Vents

    Science.gov (United States)

    Inaba, Satoshi

    2018-03-01

    Formaldehyde is abundant in the universe and one of the fundamental molecules for life. Hydrothermal vents produce a substantial amount of hydrogen molecules by serpentinization and promote reductive reactions of single carbon compounds. The abundance of formaldehyde is expected to be low due to the high Gibbs free energy in hydrothermal vents. We consider two competing formation pathways of formaldehyde: (1) the reduction of CO by H2 and (2) the reduction of HCOOH by H2 to form a methanediol, followed by the dehydration of the methanediol. We performed a number of quantum chemical simulations to examine the formation of formaldehyde in the gas phase as well as in aqueous solution. The energy barrier is significantly reduced by the catalytic effect of water molecules in aqueous solution and becomes lowest when a water cluster consisted of 5 water molecules catalyzes the reduction. The energy barrier to form a methanediol by the reduction of HCOOH is lower by 17.5 kcal/mol than that to form a formaldehyde by the reduction of CO. Considering the low energy barrier to dehydrate methanediol, the primary pathway to form formaldehyde in hydrothermal vents is concluded to be the reduction of HCOOH by H2, followed by the dehydration of methanediol.

  20. Tectonic and hydrothermal activities in Debbagh, Guelma Basin, Eastern Algeria

    Science.gov (United States)

    Maouche, S.; Abtout, A.; Merabet, N.; Aïfa, T.; Lamali, A.; Bouyahyaoui, B.; Boughchiche, S.; Ayache, M.

    2012-04-01

    Quaternary and Pliocene travertine, deposited from hot springs, can reveal much about tectonic and hydrothermal activities. The aim of this work is to understand the actual tectonic activity in the Guelma Basin and in one of its spas structure. Considering the fieldwork observations in the Hammam Debbagh area, gravity data were analyzed to better highlight the architecture of its subsurface underlying hydrothermal structures. Analysis of the gravity data included the computation of a Bouguer anomaly, upward continuations, as well as residual and derivative maps. Comparison of gravity maps, field geology, geomorphic observations and structural maps allowed us to identify the major structural features. As a result we propose a model of three subsurface structure sources at 0.2, 1 and 7 km depth from north to south, respectively. This confirms some structural elements collected from outcrops and defines subsurface structures, where the Hammam Debbagh active fault is superimposed to the hydrothermal active source in the NW-SE direction characterized by a negative gravity anomaly.

  1. Agro-industrial waste to solid biofuel through hydrothermal carbonization.

    Science.gov (United States)

    Basso, Daniele; Patuzzi, Francesco; Castello, Daniele; Baratieri, Marco; Rada, Elena Cristina; Weiss-Hortala, Elsa; Fiori, Luca

    2016-01-01

    In this paper, the use of grape marc for energy purposes was investigated. Grape marc is a residual lignocellulosic by-product from the winery industry, which is present in every world region where vine-making is addressed. Among the others, hydrothermal carbonization was chosen as a promising alternative thermochemical process, suitable for the treatment of this high moisture substrate. Through a 50 mL experimental apparatus, hydrothermal carbonization tests were performed at several temperatures (namely: 180, 220 and 250 °C) and residence times (1, 3, 8 h). Analyses on both the solid and the gaseous phases obtained downstream of the process were performed. In particular, solid and gas yields versus the process operational conditions were studied and the obtained hydrochar was evaluated in terms of calorific value, elemental analysis, and thermal stability. Data testify that hydrochar form grape marc presents interesting values of HHV (in the range 19.8-24.1 MJ/kg) and physical-chemical characteristics which make hydrochar exploitable as a solid biofuel. In the meanwhile, the amount of gases produced is very small, if compared to other thermochemical processes. This represents an interesting result when considering environmental issues. Statistical analysis of data allows to affirm that, in the chosen range of operational conditions, the process is influenced more by temperature than residence time. These preliminary results support the option of upgrading grape marc toward its energetic valorisation through hydrothermal carbonization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Hydrothermal synthesis of magnetic reduced graphene oxide sheets

    International Nuclear Information System (INIS)

    Shen, Jianfeng; Shi, Min; Ma, Hongwei; Yan, Bo; Li, Na; Ye, Mingxin

    2011-01-01

    Graphical abstract: An environmental friendly and efficient route for preparation of magnetic reduced graphene oxide composite with a one-step hydrothermal method was demonstrated. The reducing process was accompanied by generation of magnetic nanoparticles. Highlights: → A one-step hydrothermal method for preparation of MN-CCG was demonstrated. → Glucose was used as the 'green' reducing agent. → The reducing process was accompanied by generation of magnetic nanoparticles. → The prepared MN-CCG is highly water suspendable and sensitive to magnetic field. -- Abstract: We demonstrated an environmental friendly and efficient route for preparation of magnetic reduced graphene oxide composite (MN-CCG). Glucose was used as the reducing agent in this one-step hydrothermal method. The reducing process was accompanied by generation of magnetic nanoparticles. The structure and composition of the nanocomposite was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, thermal gravimetric analysis, atomic force microscopy and transmission electron microscopy. It was found that the prepared MN-CCG is highly water suspendable and sensitive to magnetic field.

  3. Zuclopenthixol acetate for acute schizophrenia and similar serious mental illnesses

    Science.gov (United States)

    Jayakody, Kaushadh; Gibson, Roger Carl; Kumar, Ajit; Gunadasa, Shalmini

    2014-01-01

    Background Medication used for acute aggression in psychiatry must have rapid onset of effect, low frequency of administration and low levels of adverse effects. Zuclopenthixol acetate is said to have these properties. Objectives To estimate the clinical effects of zuclopenthixol acetate for the management of acute aggression or violence thought to be due to serious mental illnesses, in comparison to other drugs used to treat similar conditions. Search methods We searched the Cochrane Schizophrenia’s Group Trials Register (July 2011). We supplemented this by citation searching and personal contact with authors and relevant pharmaceutical companies. Selection criteria All randomised clinical trials involving people thought to have serious mental illnesses comparing zuclopenthixol acetate with other drugs. Data collection and analysis Two review authors extracted and cross-checked data independently. We calculated fixed-effect relative risks (RR) and 95% confidence intervals (CI) for dichotomous data. We analysed by intention-to-treat. We used mean differences (MD) for continuous variables. Main results We found no data for the primary outcome, tranquillisation. Compared with haloperidol, zuclopenthixol acetate was no more sedating at two hours (n = 40, 1 RCT, RR 0.60, 95% CI 0.27 to 1.34). People given zuclopenthixol acetate were not at reduced risk of being given supplementary antipsychotics (n = 134, 3 RCTs, RR 1.49, 95% CI 0.97 to 2.30) although additional use of benzodiazepines was less (n = 50, 1 RCT, RR 0.03, 95% CI 0.00 to 0.47). People given zuclopenthixol acetate had fewer injections over seven days compared with those allocated to haloperidol IM (n = 70, 1 RCT, RR 0.39, 95% CI 0.18 to 0.84, NNT 4, CI 3 to 14). We found no data on more episodes of aggression or harm to self or others. One trial (n = 148) reported no significant difference in adverse effects for people receiving zuclopenthixol acetate compared with those allocated haloperidol at one, three

  4. Unimolecular Gas-Phase Thermolysis of Ethyl Acetate

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars

    1983-01-01

    The unimolecular gas-phase thermolysis of ethyl acetate has been investigated by the Flash-Vacuum-Thermolysis/Field-Ionization Mass Spectrometry (FVT/FI-MS) method in combination with Collision Activation (CA) mass spectrometry at 1253K. Two predominant reactions are observed: elimination...... of ethylene affording acetic acid, the latter to some extent consecutively yielding ketene, and intramolecular oxygen to oxygen ethyl group migration. Additionally minor amounts of acetaldehyde is formed. The mechanistic aspects are discussed based on 18O and 18O/ 13C labelling....

  5. Adsorption Equilibria of Acetic Acid on Activated Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyong-Mok; Nam, Hee-Geun; Mun, Sungyong [Hanyang University, Seoul (Korea, Republic of)

    2015-02-15

    In this study, the adsorption equilibria of acetic acid on activated carbon were investigated at the temperatures of 313.15 K and 323.15 K. The obtained adsorption data were then fitted by Langmuir, Bi-Langmuir, and Freundlich models, in which the relevant model parameters were determined by minimizing the sum of the squares of deviations between experimental data and calculated values. The comparison results revealed that Bi-Langmuir model could account for the adsorption equilibrium data of acetic acid with the highest accuracy among the three adsorption models considered.

  6. 4,4′-Bipyridine acetic acid disolvate

    Directory of Open Access Journals (Sweden)

    Ling Ye

    2008-01-01

    Full Text Available The crystal structure of the title compound, C10H8N2·2C2H4O2, is built up from 4,4′-bipyridine and acetic acid molecules linked by strong O—H...N hydrogen bonds. The 4,4′-bipyridine and the two acetic acid molecules are further connected through weak C—H...O hydrogen bonds to form a supramolecular two-dimensional network parallel to the (001 plane. The two pyridine rings make a dihedral angle of 31.8 (1°.

  7. Retinyl acetate-loaded nanoparticles: dermal penetration and release of the retinyl acetate.

    Science.gov (United States)

    Arayachukeat, Sunatda; Wanichwecharungruang, Supason P; Tree-Udom, Thapakorn

    2011-02-14

    Retinyl acetate (RA) loaded polymeric nanoparticle (NP) carriers were prepared using two different single polymers, ethyl cellulose (EC) and poly (ethylene glycol)-4-methoxycinnamoylphthaloylchitosan (PCPLC). The stability of RA to aqueous solution and UVA light was significantly improved when encapsulated with PCPLC, whilst EC encapsulation gave some improved stability in water but showed no improved photostability. Ex vivo application of free RA and the RA-loaded PCPLC NPs onto the surface of the freshly excised skin from a baby mouse indicated a significantly slower skin absorption rate for the encapsulated RA. However, 100% retention of the encapsulated RA in the skin tissue was observed after 24h. Confocal fluorescent analysis of the skin pieces applied with the RA-loaded PCPLC NPs indicated likely entry and accumulation of the PCPLC NPs and RA at the hair follicles. Release of RA from the PCPLC NP carriers was confirmed through the detection of an increasingly higher RA/PCPLC fluorescent signal ratio deeper into the dermis and away from the hair follicles. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Acetoanaerobium pronyense sp. nov., an anaerobic alkaliphilic bacterium isolated from a carbonate chimney of the Prony Hydrothermal Field (New Caledonia).

    Science.gov (United States)

    Bes, Méline; Merrouch, Mériem; Joseph, Manon; Quéméneur, Marianne; Payri, Claude; Pelletier, Bernard; Ollivier, Bernard; Fardeau, Marie-Laure; Erauso, Gaël; Postec, Anne

    2015-08-01

    A novel anaerobic bacterial strain, ST07-YET, was isolated from a carbonate chimney of the Prony Hydrothermal Field (PHF) in New Caledonia. Cells were Gram-stain-positive, straight rods (0.7-0.8 × 3.0-5.0 μm) and motile by means of lateral flagella. Strain ST07-YET was mesophilic (optimum 35 °C), moderately alkaliphilic and halotolerant (optimum pH 8.7 and 5 g l- 1 NaCl). Elemental sulfur, sulfate, thiosulfate, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Yeast extract, peptone, tryptone, Casamino acids, crotonate, pyruvate, galactose, maltose, sucrose, ribose, trehalose and glucose were used as carbon sources. Glucose fermentation led to acetate, H2 and CO2 formation. Arginine, serine, histidine, lysine, methionine and cysteine improved growth, but the Stickland reaction was negative for the combinations of amino acids tested. The major metabolic products from yeast extract fermentation were H2, CO2, acetate, butyrate, isobutyrate, isovalerate and propionate. The predominant cellular fatty acids were C16  :  0, C16  :  1cis9, C14  :  0 and C16  :  1cis7 (>5 % of total fatty acids). The G+C content of the genomic DNA was 32.9 mol%. Phylogenetic analysis revealed that strain ST07-YET was most closely related to Clostridium sticklandii DSM 519T and Acetoanaerobium noterae NOT-3T (96.7 % and 96.8 % 16S rRNA gene sequence similarity, respectively). On the basis of phylogenetic, chemotaxonomic and physiological properties, strain ST07-YET is proposed to represent a novel species of the genus Acetoanaerobium (order Clostridiales, phylum Firmicutes) with the name Acetoanaerobium pronyense sp. nov. The type strain is ST07-YET ( = DSM 27512T = JCM 19400T).

  9. Fate and residues of trenbolone acetate in edible tissues from sheep amd calves implanted with tritium-labeled trenbolone acetate

    International Nuclear Information System (INIS)

    Evrard, P.; Maghuin-Rogister, G.; Rico, A.G.

    1989-01-01

    In order to study the fate and residues of trenbolone acetate in edible tissues, two groups of six animals from two ruminant species (ewes and calves) were implanted with [3H]trenbolone acetate. The distribution of extractable radioactive residues was measured in liver, kidney and muscle. We found that the largest proportion of residues was not extractable and thus was considered as covalently bound residues. The proportion of the main extractable metabolites (17 alpha-trenbolone, trendione, 17 beta-trenbolone) was measured. The evaluation of the distribution of trenbolone acetate metabolites directly soluble in water showed that unknown metabolite(s) were predominant. The covalent binding to nucleic acids was measured. It was so low that it was not detectable. The results are discussed in light of the data presented in the scientific report on anabolic agents in animal production from the European scientific working group

  10. Fate and residues of trenbolone acetate in edible tissues from sheep amd calves implanted with tritium-labeled trenbolone acetate

    Energy Technology Data Exchange (ETDEWEB)

    Evrard, P.; Maghuin-Rogister, G.; Rico, A.G. (Univ. of Liege (Belgium))

    1989-06-01

    In order to study the fate and residues of trenbolone acetate in edible tissues, two groups of six animals from two ruminant species (ewes and calves) were implanted with (3H)trenbolone acetate. The distribution of extractable radioactive residues was measured in liver, kidney and muscle. We found that the largest proportion of residues was not extractable and thus was considered as covalently bound residues. The proportion of the main extractable metabolites (17 alpha-trenbolone, trendione, 17 beta-trenbolone) was measured. The evaluation of the distribution of trenbolone acetate metabolites directly soluble in water showed that unknown metabolite(s) were predominant. The covalent binding to nucleic acids was measured. It was so low that it was not detectable. The results are discussed in light of the data presented in the scientific report on anabolic agents in animal production from the European scientific working group.

  11. Density, refraction index and vapor–liquid equilibria of N-methyl-2-hydroxyethylammonium butyrate plus (methyl acetate or ethyl acetate or propyl acetate) at several temperatures

    International Nuclear Information System (INIS)

    Alvarez, V.H.; Mattedi, S.; Aznar, M.

    2013-01-01

    Highlights: ► Densities, refraction indices and VLE were measured for ester + m-2-HEAB mixtures. ► V E , apparent molar volumes and thermal expansion coefficients were calculated. ► Peng–Robinson EoS + Wong–Sandler mixing rule + COSMO-SAC predicted the data. -- Abstract: This paper reports the densities, refraction indices, and vapor liquid equilibria for binary systems ester + N-methyl-2-hydroxyethylammonium butyrate (m-2-HEAB): methyl acetate (1) + m-2-HEAB (2), ethyl acetate (1) + m-2-HEAB and propyl acetate (1) + m-2-HEAB (2). The excess molar volumes, deviations in the refraction index, apparent molar volumes, and thermal expansion coefficients for the binary systems were fitted to polynomial equations. The Peng–Robinson equation of state, coupled with the Wong–Sandler mixing rule, is used to describe the experimental data. Since the predictive activity coefficient model COSMO-SAC is used in the Wong–Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the vapor–liquid equilibria have a deviation lower than 1.0% and 1.1%, respectively

  12. Hydrothermal oxidation in the Biwabik Iron Formation, MN, USA

    Science.gov (United States)

    Losh, Steven; Rague, Ryan

    2018-02-01

    Precambrian iron formations throughout the world, notably in Australia, Brazil, and South Africa, show evidence of hypogene (≥ 110 °C, mostly > 250 °C) oxidation, alteration, and silica dissolution as a result of tectonic or magmatic activity. Although hydrothermal oxidation has been proposed for the prototype Lake Superior-type iron formation, the Biwabik Iron Formation in Minnesota (USA), it has not been documented there. By examining oxidized and unoxidized Biwabik Iron Formation in three mines, including material from high-angle faults that are associated with oxidation, we document an early hypogene oxidation event ( 175 °C) involving medium-salinity aqueous fluids (8.4 ± 4.9 wt% NaCl equiv) that infiltrated iron formation along high-angle faults. At the Hibbing Taconite Mine, hydrothermal fluids oxidized iron carbonates and silicates near faults, producing goethite ± quartz. In contrast with much of the oxidized iron ores on the Mesabi Range, silica was not removed but rather recrystallized during this event, perhaps lying in a rock-dominated system at low cumulative fluid flux. During the hydrothermal oxidation event in the Hibbing Taconite deposit, quartz-filled microfractures and irregular inclusions commonly formed in coarse variably oxidized magnetite, currently the ore mineral: these inclusions degrade the ore by introducing excess silica in magnetic concentrate. Hydrothermal oxidation at Hibbing Taconite Mine is overprinted by later, relatively minor supergene oxidation both along faults and near the surface, which locally dissolved quartz. At the Fayal Reserve Mine, widespread silicate and carbonate gangue dissolution and iron oxidation was followed by precipitation of pyrite, Mn-siderite, apatite, and other minerals in void spaces, which prevented post-oxidation compaction and significant volume loss in the sampled rocks. Although definitive temperature data for this assemblage are needed, the weight of evidence indicates that this

  13. Learning about Hydrothermal Volcanic Activity by Modeling Induced Geophysical Changes

    Directory of Open Access Journals (Sweden)

    Gilda M. Currenti

    2017-05-01

    Full Text Available Motivated by ongoing efforts to understand the nature and the energy potential of geothermal resources, we devise a coupled numerical model (hydrological, thermal, mechanical, which may help in the characterization and monitoring of hydrothermal systems through computational experiments. Hydrothermal areas in volcanic regions arise from a unique combination of geological and hydrological features which regulate the movement of fluids in the vicinity of magmatic sources capable of generating large quantities of steam and hot water. Numerical simulations help in understanding and characterizing rock-fluid interaction processes and the geophysical observations associated with them. Our aim is the quantification of the response of different geophysical observables (i.e., deformation, gravity, and magnetic fields to hydrothermal activity on the basis of a sound geological framework (e.g., distribution and pathways of the flows, the presence of fractured zones, caprock. A detailed comprehension and quantification of the evolution and dynamics of the geothermal systems and the definition of their internal state through a geophysical modeling approach are essential to identify the key parameters for which the geothermal system may fulfill the requirements to be exploited as a source of energy. For the sake of illustration only, the numerical computations are focused on a conceptual model of the hydrothermal system of Vulcano Island by simulating a generic 1-year unrest and estimating different geophysical changes. We solved (i the mass and energy balance equations of flow in porous media for temperature, pressure and density changes, (ii the elastostatic equation for the deformation field and (iii the Poisson's equations for gravity and magnetic potential fields. Under the model assumptions, a generic unrest of 1-year engenders on the ground surface low amplitude changes in the investigated geophysical observables, that, being above the accuracies of

  14. Application of Hydrothermal Treatment to High Concentrated Sewage Sludge for Anaerobic Digestion Process

    OpenAIRE

    M. Orikawa; H. Kamahara; Y. Atsuta; H. Daimon

    2013-01-01

    Tomato and seaweed were produced by utilizing CO2 and heat discharged from power generation using biogas in Toyogawa biomass park, Japan. The biogas was obtained by anaerobic digestion with hydrothermal treatment. The hydrothermal treatment was applied to the high concentrated sewage sludge (22 % total solids (TS) dewatered sludge). The purpose of this study is to clarify the effect of hydrothermal treatment on the qualities of high concentrated sewage sludge, by analyzing particulate organic...

  15. Characteristics of Biochar Obtained by Hydrothermal Carbonization of Cellulose for Renewable Energy

    OpenAIRE

    Daegi Kim; Kunio Yoshikawa; Ki Young Park

    2015-01-01

    The effect of hydrothermal carbonization on the properties of cellulose present in lignocellulosic biomass was investigated for converting it into a renewable energy resource with high energy recovery efficiency. The biochar obtained from cellulose subjected to hydrothermal carbonization showed a significant increase in its carbon content and a calorific value. 13C NMR spectroscopy showed that when raw cellulose was subjected to hydrothermal carbonization above 220 °C, the resulting biochar h...

  16. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    OpenAIRE

    Ronghua Wang; Meng Han; Qiannan Zhao; Zonglin Ren; Xiaolong Guo; Chaohe Xu; Ning Hu; Li Lu

    2017-01-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10?20?nm are uniformly composited with GNS by a two-step hydrothermal-a...

  17. Hydrothermal Helium Plumes over Submarine Volcanoes of the Marianas Arc

    Science.gov (United States)

    Lupton, J. E.; Baker, E. T.; Embley, R. W.; Resing, J. E.; Massoth, G. J.; Nakamura, K.; Greene, R.; Walker, S.; Lebon, G.

    2003-12-01

    During February-March, 2003, as part of the Submarine Ring of Fire project funded by NOAA's Ocean Exploration Program, the R/V T.G. Thompson conducted a comprehensive survey of hydrothermal activity along 1200 km of the Mariana Arc from 13.5° N to 22.5° N [see Embley et al., EOS Trans. AGU, 2003]. Plume surveys were conducted in the water-column above ~50 submarine volcanoes using a CTD/rosette system. A total of 70 CTD casts were completed, and discrete water samples were collected for analysis of a variety of hydrothermal tracers, including 3He, CH4, CO2, H2S, Fe, Mn, pH, and suspended particles. Although shorebased analysis of the samples is still underway, preliminary results indicate that about 11 of the 50 submarine volcanoes surveyed are hydrothermally active. Because many of the Marianas Arc volcanoes rise to within 500 m of the sea surface, hydrothermal plume signals such as light attenuation (suspended particles) and temperature anomaly have limited utility due to masking by near surface effects. For this reason 3He, an unambiguous hydrothermal tracer, has been particularly useful for identifying which of the shallow arc volcanoes are hydrothermally active. Our expectation was that the water-column helium signal might be reduced at shallow depths due to ventilation into the atmosphere. However, we observed very high 3He enrichments at shallow depths both at Maug Islands and at NW Rota #1 (14° 36'N; 144° 46.5'E). The 3He enrichments were strongly correlated with changes in pH, Mn, and other hydrothermal tracers. The three Maug Islands mark the perimeter of a caldera formed by an explosive eruption, and a single hydrocast in the center of the caldera detected a robust helium plume at 120-200 m depth with δ 3He reaching a maximum of 250% at 150m depth. Analysis of the co-variation of [3He] vs. [4He] at Maug gave R/Ra = 6.6 for an estimate of the end-member helium isotope ratio (R = 3He/4He and Ra = Rair). This value falls well within the range of R

  18. Effect of Acetate Group Content in Ethylene-Vinyl Acetate Copolymer on Properties of Composite Based on Low Density Polyethylene and Polyamide-6

    Directory of Open Access Journals (Sweden)

    Nhi Dinh Bui

    2016-01-01

    Full Text Available The effect of the content of vinyl acetate groups in ethylene-vinyl acetate copolymer on the properties of polymer composite based on low density polyethylene and polyamide-6 was studied. Ethylene-vinyl acetate copolymer containing less vinyl acetate groups (10–14 wt.% has a positive compatibility effect on polymer composite than ethylene-vinyl acetate copolymer containing 21–30 wt.% vinyl acetate groups. The polymer composites of LDPE, PA-6, and EVA containing 10–14 wt.% vinyl acetate groups possess the ability of biodegradation. The physical-mechanical properties of sample and molecular mass reduce after 28 days of incubation.

  19. Controlled free radical polymerization of vinyl acetate with cobalt ...

    Indian Academy of Sciences (India)

    able processes but also to the hydrolysis of environmen- tally friendly polyvinyl alcohol in the film formations, separation and bioprocesses, or coatings (figure 4). 4. Conclusion. The cobalt-mediated controlled radical polymerization of vinyl acetate was studied in bulk. It indicated a faster rate than solution polymerization.

  20. Analysis of some functional properties of acetic acid bacteria ...

    African Journals Online (AJOL)

    SARAH

    2014-03-31

    Mar 31, 2014 ... Analysis of some functional properties of acetic acid bacteria involved in Ivorian cocoa fermentation. Wilfried YAO, Honoré G. OUATTARA, Bernadette GOUALIE, Souleymane SOUMAHORO, Sébastien. NIAMKE. Laboratoire de Biotechnologies, UFR Biosciences, Université Félix HOUPHOUET-BOIGNY ...