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Sample records for catalytic water co-existing

  1. Catalytic water co-existing with a product peptide in the active site of HIV-1 protease revealed by X-ray structure analysis.

    Directory of Open Access Journals (Sweden)

    Vishal Prashar

    Full Text Available BACKGROUND: It is known that HIV-1 protease is an important target for design of antiviral compounds in the treatment of Acquired Immuno Deficiency Syndrome (AIDS. In this context, understanding the catalytic mechanism of the enzyme is of crucial importance as transition state structure directs inhibitor design. Most mechanistic proposals invoke nucleophilic attack on the scissile peptide bond by a water molecule. But such a water molecule coexisting with any ligand in the active site has not been found so far in the crystal structures. PRINCIPAL FINDINGS: We report here the first observation of the coexistence in the active site, of a water molecule WAT1, along with the carboxyl terminal product (Q product peptide. The product peptide has been generated in situ through cleavage of the full-length substrate. The N-terminal product (P product has diffused out and is replaced by a set of water molecules while the Q product is still held in the active site through hydrogen bonds. The position of WAT1, which hydrogen bonds to both the catalytic aspartates, is different from when there is no substrate bound in the active site. We propose WAT1 to be the position from where catalytic water attacks the scissile peptide bond. Comparison of structures of HIV-1 protease complexed with the same oligopeptide substrate, but at pH 2.0 and at pH 7.0 shows interesting changes in the conformation and hydrogen bonding interactions from the catalytic aspartates. CONCLUSIONS/SIGNIFICANCE: The structure is suggestive of the repositioning, during substrate binding, of the catalytic water for activation and subsequent nucleophilic attack. The structure could be a snap shot of the enzyme active site primed for the next round of catalysis. This structure further suggests that to achieve the goal of designing inhibitors mimicking the transition-state, the hydrogen-bonding pattern between WAT1 and the enzyme should be replicated.

  2. Catalytic Water Co-Existing with a Product Peptide in the Active Site of HIV-1 Protease Revealed by X-Ray Structure Analysis

    OpenAIRE

    Prashar, Vishal; Bihani, Subhash; Das, Amit; Ferrer, Jean-Luc; Hosur, Madhusoodan

    2009-01-01

    Background It is known that HIV-1 protease is an important target for design of antiviral compounds in the treatment of Acquired Immuno Deficiency Syndrome (AIDS). In this context, understanding the catalytic mechanism of the enzyme is of crucial importance as transition state structure directs inhibitor design. Most mechanistic proposals invoke nucleophilic attack on the scissile peptide bond by a water molecule. But such a water molecule coexisting with any ligand in the active site has not...

  3. Heterogeneous water supply affects growth and benefits of clonal integration between co-existing invasive and native Hydrocotyle species

    Science.gov (United States)

    Wang, Yong-Jian; Bai, Yun-Fei; Zeng, Shi-Qi; Yao, Bin; Wang, Wen; Luo, Fang-Li

    2016-01-01

    Spatial patchiness and temporal variability in water availability are common in nature under global climate change, which can remarkably influence adaptive responses of clonal plants, i.e. clonal integration (translocating resources between connected ramets). However, little is known about the effects of spatial patchiness and temporal heterogeneity in water on growth and clonal integration between congeneric invasive and native Hydrocotyle species. In a greenhouse experiment, we subjected severed or no severed (intact) fragments of Hydrocotyle vulgaris, a highly invasive species in China, and its co-existing, native congener H. sibthorpioides to different spatial patchiness (homogeneous and patchy) and temporal interval (low and high interval) in water supply. Clonal integration had significant positive effects on growth of both species. In the homogeneous water conditions, clonal integration greatly improved the growth in fragments of both species under low interval in water. However, in the patchy water conditions, clonal integration significantly increased growth in both ramets and fragments of H. vulgaris under high interval in water. Therefore, spatial patchiness and temporal interval in water altered the effects of clonal integration of both species, especially for H. vulgaris. The adaptation of H. vulgaris might lead to invasive growth and potential spread under the global water variability. PMID:27439691

  4. Heterogeneous water supply affects growth and benefits of clonal integration between co-existing invasive and native Hydrocotyle species.

    Science.gov (United States)

    Wang, Yong-Jian; Bai, Yun-Fei; Zeng, Shi-Qi; Yao, Bin; Wang, Wen; Luo, Fang-Li

    2016-01-01

    Spatial patchiness and temporal variability in water availability are common in nature under global climate change, which can remarkably influence adaptive responses of clonal plants, i.e. clonal integration (translocating resources between connected ramets). However, little is known about the effects of spatial patchiness and temporal heterogeneity in water on growth and clonal integration between congeneric invasive and native Hydrocotyle species. In a greenhouse experiment, we subjected severed or no severed (intact) fragments of Hydrocotyle vulgaris, a highly invasive species in China, and its co-existing, native congener H. sibthorpioides to different spatial patchiness (homogeneous and patchy) and temporal interval (low and high interval) in water supply. Clonal integration had significant positive effects on growth of both species. In the homogeneous water conditions, clonal integration greatly improved the growth in fragments of both species under low interval in water. However, in the patchy water conditions, clonal integration significantly increased growth in both ramets and fragments of H. vulgaris under high interval in water. Therefore, spatial patchiness and temporal interval in water altered the effects of clonal integration of both species, especially for H. vulgaris. The adaptation of H. vulgaris might lead to invasive growth and potential spread under the global water variability. PMID:27439691

  5. Catalytic distillation water recovery subsystem

    Science.gov (United States)

    Budininkas, P.; Rasouli, F.

    1985-01-01

    An integrated engineering breadboard subsystem for the recovery of potable water from untreated urine based on the vapor phase catalytic ammonia removal was designed, fabricated and tested. Unlike other evaporative methods, this process catalytically oxidizes ammonia and volatile hydrocarbons vaporizing with water to innocuous products; therefore, no pretreatment of urine is required. Since the subsystem is fabricated from commercially available components, its volume, weight and power requirements are not optimized; however, it is suitable for zero-g operation. The testing program consists of parametric tests, one month of daily tests and a continuous test of 168 hours duration. The recovered water is clear, odorless, low in ammonia and organic carbon, and requires only an adjustment of its pH to meet potable water standards. The obtained data indicate that the vapor phase catalytic ammonia removal process, if further developed, would also be competitive with other water recovery systems in weight, volume and power requirements.

  6. Glycol-Water Interactions and co-existing phases and Temperature Dependent Solubility. An Example Of Carbon-Hydrogen Chemistry In Water

    CERN Document Server

    Michael, Fredrick

    2010-01-01

    Recently there has been great interest in Glycol-Water chemistry and solubility and temperature dependent phase dynamics. The Glycol-Water biochemistry of interactions is present in plant biology and chemistry, is of great interest to chemical engineers and biochemists as it is a paradigm of Carbon-Hydrogen Water organic chemistry. There is an interest moreover in formulating a simpler theory and computation model for the Glycol-Water interaction and phase dynamics, that is not fully quantum mechanical yet has the high accuracy available from a fully quantum mechanical theory of phase transitions of fluids and Fermi systems. Along these lines of research interest we have derived a Lennard-Jones -like theory of interacting molecules-Water in a dissolved adducts of Glycol-Water system interacting by Hydrogen bonds whose validity is supported at the scale of interactions by other independent molecular dynamics investigations that utilize force fields dependent on their experimental fittings to the Lennard-Jones ...

  7. Biogeochemical redox cycling of arsenic in mine-impacted lake sediments and co-existing pore waters near Giant Mine, Yellowknife Bay, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.F. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Jamieson, H.E., E-mail: jamieson@geol.queensu.ca [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Kyser, T.K. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Praharaj, T.; Fortin, D. [University of Ottawa, Department of Earth Sciences, Ottawa, K1A 3N5 (Canada)

    2010-02-15

    Lacustrine sediments, submerged tailings, and their pore waters have been collected at several sites in Yellowknife Bay, Great Slave Lake, Canada, in order to investigate the biogeochemical controls on the remobilization of As from mining-impacted materials under different depositional conditions. Radiometric dating confirms that a mid-core enrichment of Pb, Zn, Cu and Sb corresponds to the opening of a large Au mine 60 a ago. This was evident even in a relatively remote site. Arsenic was enriched at mid-core, coincident with mining activity, but clearly exhibited post-depositional mobility, migrating upwards towards the sediment water interface (SWI) as well as down-core. Deep-water (15 m) Yellowknife Bay sediments that contain buried mine waste are suboxic, relatively organic-rich and abundant in microbes with As in pore waters and sediments reaching 585 {mu}g/L and 1310 mg/kg, respectively. Late summer pore waters show equal proportions of As(III) and As(V) (16-415 {mu}g/L) whereas late winter pore waters are dominated by As(III) (284-947 {mu}g/L). This can be explained by As(III) desorption mechanisms associated with the conversion of FeS to FeS{sub 2} and the reduction of As(V) to As(III) through the oxidation of dissolved sulfide, both microbially-mediated processes. Processes affecting As cycling involve the attenuating efficiency of the oxic zone at the SWI, sediment redox heterogeneity and the reductive dissolution of Fe(hydr)oxides by labile organic matter, temporarily and spatially variable.

  8. Silver nanocluster catalytic microreactors for water purification

    Science.gov (United States)

    Da Silva, B.; Habibi, M.; Ognier, S.; Schelcher, G.; Mostafavi-Amjad, J.; Khalesifard, H. R. M.; Tatoulian, M.; Bonn, D.

    2016-07-01

    A new method for the elaboration of a novel type of catalytic microsystem with a high specific area catalyst is developed. A silver nanocluster catalytic microreactor was elaborated by doping a soda-lime glass with a silver salt. By applying a high power laser beam to the glass, silver nanoclusters are obtained at one of the surfaces which were characterized by BET measurements and AFM. A microfluidic chip was obtained by sealing the silver coated glass with a NOA 81 microchannel. The catalytic activity of the silver nanoclusters was then tested for the efficiency of water purification by using catalytic ozonation to oxidize an organic pollutant. The silver nanoclusters were found to be very stable in the microreactor and efficiently oxidized the pollutant, in spite of the very short residence times in the microchannel. This opens the way to study catalytic reactions in microchannels without the need of introducing the catalyst as a powder or manufacturing complex packed bed microreactors.

  9. Water recovery by catalytic treatment of urine vapor

    Science.gov (United States)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  10. Degradation of Organic Pollutants in Water by Catalytic Ozonation

    Institute of Scientific and Technical Information of China (English)

    LI Xin; YAO Jun-hai; QI Jing-yao

    2007-01-01

    Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental results indicate that Cu/Al2O3 has a very effective catalytic activity during the ozonation of organic pollutants in water. The optimum conditions for preparing Cu/Al2O3 were systematically investigated with the orthogonal testing method. Furthermore, the results also show that the surface properties of catalyst are not compulsory for effective oxidation.

  11. Co-existence of Organic and GM Agriculture

    OpenAIRE

    Boelt, Birte

    2004-01-01

    The Danish Minister for Food, Agriculture and Fisheries presented in spring 2004 a bill on co-existence of genetically modified, conventional and organic crops in support of the free choice of consumers and to ensure development possibilities for new and existing production forms. The bill contains a framework for regulation based on crop specific control measures, communication among farmers and mandatory courses in GM cultivation. The identification of control measures is based on the repor...

  12. Co-existence of Bronchiectasis and Chronic Obstructive Pulmonary Disease.

    Science.gov (United States)

    Goel, Nitin; Gupta, Pawan; Singh, Abhijeet; Prasad, Rajendra

    2015-01-01

    We present the case of a 56-year-old male who presented with cough and breathlessness. Chest radiograph (postero-anterior view) showed bulla and signs of hyperinflation in the right upper zone with cystic shadows in the left lower zone. Spirometry showed severe irreversible airflow obstruction with restriction and decreased diffusion capacity for carbon monoxide. On high resolution computed tomography (HRCT), right upper lobe bulla with emphysematous changes and left lower lobe cystic bronchiectasis were seen. Considering its rarity of occurrence and paucity of data in literature regarding co-existence of bronchiectasis with emphysema, this case is being reported. PMID:26591975

  13. Co-existence of Pulmonary, Tonsillar and Laryngeal Tuberculosis

    Directory of Open Access Journals (Sweden)

    Erkan Ceylan

    2013-10-01

    Full Text Available    A 56-year old man applied to otorhinolaryngology clinic with sore throat, dysphagia. During direct examination, left palatine tonsil and tonsil plicas ulcerovegetative lesions were found. In the indirect laryngoscopy, in some regions of the larynx and epiglottis, ulcerovegetative lesions were observed too. Because of suspicion of laryngeal carcinoma and metastasis, punch biopsy of the left palatine tonsil was performed. Chest x-ray and computerized tomography of the thorax revealed two adjacent cavitations in the apicoposterior segment of the left upper lobe. In the histopathologic examination of biopsies, granulomatous structures that proved tuberculosis were observed. In the fiberoptic bronchoscopic analysis, endobronchial lesion was not detected. Acid-fast bacilli were determined in sputum and bronchial lavage in microscopy and culture. The case of this middle aged male patient with co-existence of tonsillar, laryngeal and pulmonary tuberculosis presents the clinical significance of upper airway tuberculosis in terms of its infectiousness and rare occurrence.

  14. Nuclear power generation and co-existence with local area

    International Nuclear Information System (INIS)

    In addition to originally strong anxiety and unreliability on nuclear power generation, frequent accidents and troubles in the old Nuclear Reactor and Fuels Development Incorporation (the new Nuclear Fuel Cycle Development Incorporation), a fact that numbers of opposition group was over a half at citizen's vote conducted first in Japan and at Maki-machi in Niigata prefecture in August, 1996 on location of a nuclear power generation of the Tohoku Electric Co., Ltd., and so forth, affects some ripple effects to make difficult to form consensus on new location of a nuclear power generation. On making consensus of such location, every electric companies practise good communication with location areas, communication and other organizations, and so forth, promote positive information supplies and conversation type understanding works, and effort to acquire reliability for people of the location areas. Together with such efforts, they accumulate steadily safe operation results of the present nuclear power plants and develop nuclear PA (public acceptance) actions, local area promotion supporting countermeasures, and so forth. Here was introduced on a part of actions aiming at assistance to and co-existence with local areas promoted by every electric companies on various forms. (G.K.)

  15. Genes and processed paralogs co-exist in plant mitochondria.

    Science.gov (United States)

    Cuenca, Argelia; Petersen, Gitte; Seberg, Ole; Jahren, Anne Hoppe

    2012-04-01

    RNA-mediated gene duplication has been proposed to create processed paralogs in the plant mitochondrial genome. A processed paralog may retain signatures left by the maturation process of its RNA precursor, such as intron removal and no need of RNA editing. Whereas it is well documented that an RNA intermediary is involved in the transfer of mitochondrial genes to the nucleus, no direct evidence exists for insertion of processed paralogs in the mitochondria (i.e., processed and un-processed genes have never been found simultaneously in the mitochondrial genome). In this study, we sequenced a region of the mitochondrial gene nad1, and identified a number of taxa were two different copies of the region co-occur in the mitochondria. The two nad1 paralogs differed in their (a) presence or absence of a group II intron, and (b) number of edited sites. Thus, this work provides the first evidence of co-existence of processed paralogs and their precursors within the plant mitochondrial genome. In addition, mapping the presence/absence of the paralogs provides indirect evidence of RNA-mediated gene duplication as an essential process shaping the mitochondrial genome in plants.

  16. Catalytic hydrolysis for the degradation of organophosphorus pesticides in water

    International Nuclear Information System (INIS)

    The kinetic studies of catalytic hydrolysis revealed that the concentration of two kinds of organophosphorus pesticides (omethoate and methidathion) in solution apparently decays according to the second order reaction. It was found that the rate constant value was highest at strong acidic conditions and it continued to decrease as the pH of the solution was increased. At basic conditions the rate constant value decreased to minimum. Manganese dioxide under acidic conditions converted into Mn/sup 2+/ ions and then these ions in water form hexaaquomanganese (II) ion. This hexaaquomanganese (II ion then adsorbed itself on the S or O atom of the organophosphorus compound and thus weakens the bond between P-S. This reaction facilitated the attack of H/sub 2/O or OH/sup -/ ion and thus enhanced the efficiency of hydrolysis. It was studied that methidathion hydrolyzed more efficiently than omethoate The rate constants of catalytic hydrolysis were increased with increasing the amount of MnO/sub 2/. It was found that the pesticides had undergone adsorption on catalyst in the first few minutes and there was the rapid drop of total phosphorus concentration. The decrease of total phosphorus adsorption with increasing pH was also observed. After the addition of alkaline earth metal cations (Ca/sup 2+/ and Mg/sup 2+/) along with magnesium, the enhancement in the efficiency of hydrolysis at near neutral conditions occurred. (author)

  17. The plausible role of carbonate in photo-catalytic water oxidation processes.

    Science.gov (United States)

    Kornweitz, Haya; Meyerstein, Dan

    2016-04-28

    DFT calculations point out that the photo-oxidation of water on GaN is energetically considerably facilitated by adsorbed carbonate. As the redox potential of the couple CO3(˙-)/CO3(2-) is considerably lower than that of the couple OH˙/OH(-) but still enables the oxidation of water it is suggested that carbonate should be considered as a catalyst/co-catalyst in a variety of catalytic/photo-catalytic/electro-catalytic oxidation processes.

  18. Experimental studies on catalytic hydrogen recombiners for light water reactors

    International Nuclear Information System (INIS)

    In the course of core melt accidents in nuclear power plants a large amount of hydrogen can be produced and form an explosive or even detonative gas mixture with aerial oxygen in the reactor building. In the containment atmosphere of pressurized water reactors hydrogen combines a phlogistically with the oxygen present to form water vapor even at room temperature. In the past, experimental work conducted at various facilities has contributed little or nothing to an understanding of the operating principles of catalytic recombiners. Hence, the purpose of the present study was to conduct detailed investigations on a section of a recombiner essentially in order to deepen the understanding of reaction kinetics and heat transport processes. The results of the experiments presented in this dissertation form a large data base of measurements which provides an insight into the processes taking place in recombiners. The reaction-kinetic interpretation of the measured data confirms and deepens the diffusion theory - proposed in an earlier study. Thus it is now possible to validate detailed numeric models representing the processes in recombiners. Consequently the present study serves to broaden and corroborate competence in this significant area of reactor technology. In addition, the empirical knowledge thus gained may be used for a critical reassessment of previous numeric model calculations. (orig.)

  19. Energy Conservation:Challenges and Opportunities Co-existing

    Institute of Scientific and Technical Information of China (English)

    Sun Yongjian

    2006-01-01

    @@ Yang Zhenhuai, Chairman, China Energy Conservation Association:China such has a large population,but natural resources as infields, water, oil and gas, etc.,are in comparative scarce. The zoology environment is comparatively weak. During the past 20 years, the economic growth has been realized mainly on through resource exploitation, heavy pollution and expansion, the environmental pollution and zoological destruction have developed to a very serious extent.

  20. Energy Conservation:Challenges and Opportunities Co-existing

    Institute of Scientific and Technical Information of China (English)

    Sun; Yongjian

    2006-01-01

      Yang Zhenhuai, Chairman, China Energy Conservation Association:China such has a large population,but natural resources as infields, water, oil and gas, etc.,are in comparative scarce. The zoology environment is comparatively weak. During the past 20 years, the economic growth has been realized mainly on through resource exploitation, heavy pollution and expansion, the environmental pollution and zoological destruction have developed to a very serious extent.……

  1. Hydrogen production by catalytic gasification of cellulose in supercritical water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cellulose,one of the important components of biomass,was gasified in supercritical water to produce hydrogen-rich gas in an autoclave which was operated batch-wise under high-pressure.K2CO3 and Ca(OH)2 were selected as the catalysts (or promoters).The temperature was kept between 450℃ and 500℃ while pressure was maintained at 24-26 MPa.The reaction time was 20 min.Experimental results showed that the two catalysts had good catalytic effect and optimum amounts were observed for each catalyst.When 0.2 g K2CO3 was added,the hydrogen yield could reach 9.456 mol.kg-1 which was two times of the H2 amount produced without catalyst.When 1.6 g Ca(OH)2 was added,the H2 yield was K2CO3 as catalyst but is still 1.7 times that achieved without catalyst.Comparing with the results obtained using KaCO3 or Ca(OH)2 alone,the use of a combination of K2CO3 and Ca(OH)2 could increase the H2 yield by up to 2.5 times that without catalyst and 25% and 45% more than that obtained using K2CO3 and Ca(OH)2 alone,respectively.It was found that methane was the dominant product at relatively low temperature.When the temperature was increased,the methane reacts with water and is converted to hydrogen and carbon dioxide.

  2. The progress of catalytic technologies in water purification:a review

    Institute of Scientific and Technical Information of China (English)

    LI Dapeng; QU Jiuhui

    2009-01-01

    Catalytic technologies have been paid increasing attention in refractory pollutants abatement due to its practical and potential values in water purification.As effective and efficient approaches for water purification,Fenton's reagent,ozonation,electrochemical and photocatalytic methods have been widely studied and applied in different aspects and have been reviewed by several papers.In recent years,some novel catalytic processes based on above processes have been developed for enhancing the efficiency of removing the organics form water.This reviews emphasize on the recent development of heterogeneous catalytic ozonation,electrocatalysis in respect of novel electrodes and electro-Fenton method (EF),photoelectrocatalysis process (PEC) and photoelectron-Fenton (PEF) in water purification.It is also an attempt to propose general ideas about mechanism and principle enhancing the catalytic efficiency for degradation and mineralization of organics in water.

  3. Single-chain folding of polymers for catalytic systems in water.

    Science.gov (United States)

    Terashima, Takaya; Mes, Tristan; De Greef, Tom F A; Gillissen, Martijn A J; Besenius, Pol; Palmans, Anja R A; Meijer, E W

    2011-04-01

    Enzymes are a source of inspiration for chemists attempting to create versatile synthetic catalysts. In order to arrive at a polymeric chain carrying catalytic units separated spatially, it is a prerequisite to fold these polymers in water into well-defined compartmentalized architectures thus creating a catalytic core. Herein, we report the synthesis, physical properties, and catalytic activity of a water-soluble segmented terpolymer in which a helical structure in the apolar core is created around a ruthenium-based catalyst. The supramolecular chirality of this catalytic system is the result of the self-assembly of benzene-1,3,5-tricarboxamide side chains, while the catalyst arises from the sequential ruthenium-catalyzed living radical polymerization of the different monomers followed by ligand exchange. The polymers exhibit a two-state folding process and show transfer hydrogenation in water. PMID:21405022

  4. Osteomalacia and coxa vara. An unusual co-existence for femoral neck stress fracture

    Directory of Open Access Journals (Sweden)

    Kerim Sariyilmaz

    2015-01-01

    Conclusion: Joint and bone pain without any trauma should be investigated and bone metabolism disorders should be kept in mind. There might be co-existing factors related with stress fractures, and they must be treated simultaneously.

  5. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii

    OpenAIRE

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A.; Rommereim, Leah M.; Bzik, David J.; Yap, George S.

    2013-01-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of s...

  6. Co-existence of Sarcina Organisms and Helicobacter pylori Gastritis/Duodenitis in Pediatric Siblings

    OpenAIRE

    Sauter, Jennifer L.; Nayar, Suresh K.; Anders, Paige D.; D’Amico, Michael; Butnor, Kelly J.; Wilcox, Rebecca L.

    2013-01-01

    Sarcina are gram-positive anaerobic bacteria found to be associated with delayed gastric emptying and gastric outlet obstruction. We describe two cases of Sarcina co-existing with Helicobacter pylori organisms in pediatric siblings presenting within four months of each other with pyloric obstruction secondary to severe gastritis/duodenitis. The co-existence of Sarcina and Helicobacter pylori has not, to our knowledge, been previously reported. Its characteristic tetrad packeted morphology per...

  7. Radiation-catalytical properties of natural zeolite of mordenite type during radiolysis of water

    International Nuclear Information System (INIS)

    Radiation-catalytic properties of natural zeolite of mordenite type in cation Na+, K+, Ca2+, Ba2+ forms during radiolysis of water molecules were investigated with the use of 60Co γ-radiation (6 Gy/s). Kinetic parameters of radiolysis of water molecules in the presence of these zeolite samples were determined. It was revealed that zeolite of mordenite type catalyzes the radiolysis water molecules, its catalytic activity growing with decrease in ionic radius of the cation in the zeolite composition

  8. [Catalytic ozonation of nitrobenzene in water by acidification-activated red mud].

    Science.gov (United States)

    Kang, Ya-ning; Li, Hua-nan; Xu, Bing-bing; Qi, Fei; Zhao, Lun

    2013-05-01

    Red mud as one kind of aluminum industrial wastes was used as raw material for catalyst preparation. It was activated by acidification in order to enhance its catalytic activity in the system of catalytic ozonation. Furthermore, removal performance and reaction mechanism in degradation of organic pollutants were discussed. Results showed that acid modified red mud had more significant catalytic activity than the raw red mud. The removal efficiency of nitrobenzene by catalytic ozonation with acidified red mud (RM6.0) increased with the increasing ozone concentration. When the ozone concentration was increased from 0.4 mg x L(-1) to 1.7 mg x L(-1), the removal efficiency of nitrobenzene increased from 45% to 92%. There was a consistent effect of water pH on the removal efficiency and the ozone concentration variation. The variation of the removal efficiency depended on the initial water pH. This was because the concentration of OH(-) led to ozone decomposition to generate hydroxyl radicals. The higher water pH value led to the quenching of hydroxyl radicals, resulting in the reduction of catalytic activity of RM6.0. The experimental results of aqueous ozone concentration variation in the presence of RM6.0 and inhibition by hydroxyl radicals indicated that the main reaction mechanism was catalytic ozonation of NB. Firstly, aqueous ozone was absorbed onto the surface of RM6.0, and then the concentrated ozone oxidized NB in water which was with a combination of direct and indirect oxidation. In catalytic reaction, hydroxyl radicals were present, which were generated during the oxidation of NB on the surface of RM6.0.

  9. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    Science.gov (United States)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  10. Catalytic water oxidation by mononuclear Ru complexes with an anionic ancillary ligand.

    Science.gov (United States)

    Tong, Lianpeng; Inge, A Ken; Duan, Lele; Wang, Lei; Zou, Xiaodong; Sun, Licheng

    2013-03-01

    Mononuclear Ru-based water oxidation catalysts containing anionic ancillary ligands have shown promising catalytic efficiency and intriguing properties. However, their insolubility in water restricts a detailed mechanism investigation. In order to overcome this disadvantage, complexes [Ru(II)(bpc)(bpy)OH2](+) (1(+), bpc = 2,2'-bipyridine-6-carboxylate, bpy = 2,2'-bipyridine) and [Ru(II)(bpc)(pic)3](+) (2(+), pic = 4-picoline) were prepared and fully characterized, which features an anionic tridentate ligand and has enough solubility for spectroscopic study in water. Using Ce(IV) as an electron acceptor, both complexes are able to catalyze O2-evolving reaction with an impressive rate constant. On the basis of the electrochemical and kinetic studies, a water nucleophilic attack pathway was proposed as the dominant catalytic cycle of the catalytic water oxidation by 1(+), within which several intermediates were detected by MS. Meanwhile, an auxiliary pathway that is related to the concentration of Ce(IV) was also revealed. The effect of anionic ligand regarding catalytic water oxidation was discussed explicitly in comparison with previously reported mononuclear Ru catalysts carrying neutral tridentate ligands, for example, 2,2':6',2″-terpyridine (tpy). When 2(+) was oxidized to the trivalent state, one of its picoline ligands dissociated from the Ru center. The rate constant of picoline dissociation was evaluated from time-resolved UV-vis spectra.

  11. Recycle attuned catalytic exchange (RACE) for reliable and low inventory processing of highly tritiated water

    International Nuclear Information System (INIS)

    The detritiation of highly tritiated water by liquid phase catalytic exchange needs dilution of the feed with water to tritium concentrations suitable for catalyst and safety rules and to assure flow rates large enough for wetting the catalyst. Dilution by recycling detritiated water from within the exchange process has three advantages: the amount and concentration of the water for dilution is controlled within the exchange process, there is no additional water load to processes located downstream RACE, and the ratio of gas to liquid flow rates in the exchange column could be adjusted by using several recycles differing in amount and concentration to avoid an excessively large number of theoretical separation stages. In this paper, the flexibility of the recycle attuned catalytic exchange (RACE) and its effect on the cryogenic distillation are demonstrated for the detritiation of the highly tritiated water from a tritium breeding blanket

  12. The ISS Water Processor Catalytic Reactor as a Post Processor for Advanced Water Reclamation Systems

    Science.gov (United States)

    Nalette, Tim; Snowdon, Doug; Pickering, Karen D.; Callahan, Michael

    2007-01-01

    Advanced water processors being developed for NASA s Exploration Initiative rely on phase change technologies and/or biological processes as the primary means of water reclamation. As a result of the phase change, volatile compounds will also be transported into the distillate product stream. The catalytic reactor assembly used in the International Space Station (ISS) water processor assembly, referred to as Volatile Removal Assembly (VRA), has demonstrated high efficiency oxidation of many of these volatile contaminants, such as low molecular weight alcohols and acetic acid, and is considered a viable post treatment system for all advanced water processors. To support this investigation, two ersatz solutions were defined to be used for further evaluation of the VRA. The first solution was developed as part of an internal research and development project at Hamilton Sundstrand (HS) and is based primarily on ISS experience related to the development of the VRA. The second ersatz solution was defined by NASA in support of a study contract to Hamilton Sundstrand to evaluate the VRA as a potential post processor for the Cascade Distillation system being developed by Honeywell. This second ersatz solution contains several low molecular weight alcohols, organic acids, and several inorganic species. A range of residence times, oxygen concentrations and operating temperatures have been studied with both ersatz solutions to provide addition performance capability of the VRA catalyst.

  13. Catalytic Conversion of Glucose into 5-Hydroxymethylfurfural by Hf(OTf4 Lewis Acid in Water

    Directory of Open Access Journals (Sweden)

    Junjie Li

    2015-12-01

    Full Text Available A series of Lewis acidic metal salts were used for glucose dehydration to 5-hydroymethylfurfural (HMF in water. Effect of valence state, ionic radii of Lewis acidic cation, and the type of anions on the catalytic performance have been studied systematically. The experimental results showed that the valence state played an important role in determining catalytic activity and selectivity. It was found that a higher glucose conversion rate and HMF selectivity could be obtained over high valent Lewis acid salts, where the ionic radii of these Lewis acidic metal salts are usually relatively small. Analysis on the effect of the anions of Lewis acid salts on the catalytic activity and the selectivity suggested that a higher glucose conversion and HMF selectivity could be readily obtained with Cl−. Furthermore, the recyclability of high valence state Lewis acid salt was also studied, however, inferior catalytic performance was observed. The deactivation mechanism was speculated to be the fact that high valence state Lewis acid salt was comparatively easier to undergo hydrolysis to yield complicated metal aqua ions with less catalytic activity. The Lewis acidic activity could be recovered by introducing a stoichiometric amount of hydrochloric acid (HCl to the catalytic before the reaction.

  14. Catalytic Response and Stability of Nickel/Alumina for the Hydrogenation of 5-Hydroxymethylfurfural in Water.

    Science.gov (United States)

    Perret, Noémie; Grigoropoulos, Alexios; Zanella, Marco; Manning, Troy D; Claridge, John B; Rosseinsky, Matthew J

    2016-03-01

    The catalytic response of Ni on Al2O3 obtained from Ni-Al layered double hydroxides was studied for the liquid-phase hydrogenation of hydroxymethyl furfural to tetrahydrofuran-2,5-diyldimethanol (THFDM) in water. The successive calcination and reduction of the precursors caused the removal of interlayer hydroxyl and carbonate groups and the reduction of Ni(2+) to Ni(0). Four reduced mixed oxide catalysts were obtained, consisting of different amount of Ni metal contents (47-68 wt%) on an Al-rich amorphous component. The catalytic activity was linked to Ni content whereas selectivity was mainly affected by reaction temperature. THFDM was formed in a stepwise manner at low temperature (353 K) whereas 3-hydroxymethyl cyclopentanone was generated at higher temperature. Coke formation caused deactivation; however, the catalytic activity can be regenerated using heat treatment. The results establish Ni on Al2O3 as a promising catalyst for the production of THFDM in water. PMID:26870940

  15. Co-existing institutional logics and agency among top-level public servants

    DEFF Research Database (Denmark)

    Bjerregaard, Toke

    2011-01-01

    to address parts of this void. This study examines the agency exerted by top-level public servants through their everyday strategy and policy work in face of co-existing logics of public administration. The findings illustrate how their action strategies span from more passive strategies of coping...... with coexisting logics of administration to more skilled agency of combining logics aimed at enhancing their opportunity and action space. The study suggests that the interplay between co-existing institutional logics, action strategies and the practical skills of top-level public servants provides the basis...... for both coping and more proactive strategies in pluralistic public administrations. Findings illustrate the role of public servants' practical sense of realizable opportunities that inform such strategies of handling co-existing institutional logics. Implications for institutional studies of organizations...

  16. GMO neighbourhoods - will co-existence be a geographically realistic possibility?

    DEFF Research Database (Denmark)

    Qvist, H. Witt; Lundsgaard, H.; Brandt, Jesper

    2006-01-01

    of the precautionary principle adopted in the Maastricht treaty from 1992 by the EU (Andersen, 2000). We concretised these rules in relation to actual landscape practices among primary producers of sugar beet in Denmark, we simulated the co-existence of GM and conventional sugar beet in an area of...... after the study took place. It is concluded that although the farmers are positive towards the possibility of introducing GM sugar beet, it is not realistic to expect the rules of co-existence to be observed, which makes the risk assessment behind the new rules unrealistical. Further studies of social...... practice in relation to trends and geographical variations in the distribution of structure, size and fragmentation of agricultural holdings are recommended in order to investigate possibilities for realistic co-existence....

  17. Free and Open Source ERP - distinction, direction, co-existence and potentials

    DEFF Research Database (Denmark)

    Tambo, Torben; Koch, Christian

    2011-01-01

    processes, and absence of flexibility to change suppliers and systems. FOS-ERP does offer an answer to most of these questions, but is facing issues in market penetration. In this chapter barriers of FOS-ERP are reviewed; proposals are made on how to manage barriers. An approach of targeted co......-existence is made suggestions for solutions are explained. Conclusively, FOS-ERP is seen as a strong option for enterprises in the future, but a clear understanding and distinction must be the offset, barriers needs to be managed, and optimal co-existence will in most cases be the realistic scenario....

  18. Photocatalytic Water-Splitting Reaction from Catalytic and Kinetic Perspectives

    KAUST Repository

    Hisatomi, Takashi

    2014-10-16

    Abstract: Some particulate semiconductors loaded with nanoparticulate catalysts exhibit photocatalytic activity for the water-splitting reaction. The photocatalysis is distinct from the thermal catalysis because photocatalysis involves photophysical processes in particulate semiconductors. This review article presents a brief introduction to photocatalysis, followed by kinetic aspects of the photocatalytic water-splitting reaction.Graphical Abstract: [Figure not available: see fulltext.

  19. Session 6: Catalytic Dechlorination Reaction of Chlorinated Hydrocarbons with Water Using nano-structured Alumina

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Khaleel [United Arab Emirates Univ., Dept. of Chemistry, Al-Ain (United States)

    2004-07-01

    Herein, we report our recent results from a study on the catalytic dechlorination reactions of 1,2-dichloroethane (DCE) and carbon tetrachloride (CTC) with water using HSA-Al{sub 2}O{sub 3} as the catalyst. The obtained experimental results are explained. (O.M.)

  20. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop advanced catalysts for a volatile removal assembly used to purify spacecraft water. The innovation of the proposed...

  1. Conserved water-mediated H-bonding dynamics of catalytic Asn 175 in plant thiol protease

    Indian Academy of Sciences (India)

    Tapas K Nandi; Hridoy R Bairagya; Bishnu P Mukhopadhyay; K Sekar; Dipankar Sukul; Asim K Bera

    2009-03-01

    The role of invariant water molecules in the activity of plant cysteine protease is ubiquitous in nature. On analysing the 11 different Protein DataBank (PDB) structures of plant thiol proteases, the two invariant water molecules W1 and W2 (W220 and W222 in the template 1PPN structure) were observed to form H-bonds with the Ob atom of Asn 175. Extensive energy minimization and molecular dynamics simulation studies up to 2 ns on all the PDB and solvated structures clearly revealed the involvement of the H-bonding association of the two water molecules in fixing the orientation of the asparagine residue of the catalytic triad. From this study, it is suggested that H-bonding of the water molecule at the W1 invariant site better stabilizes the Asn residue at the active site of the catalytic triad.

  2. Carbon and oxygen isotopes in apatite CO2 and co-existing calcite

    International Nuclear Information System (INIS)

    Carbon and oxygen isotopes were analyzed in carbonate apatite CO2 and in co-existing calcite. Both C and O in apatite CO2 are enriched in the respective light isotopes relative to calcite. These results confirm the proposition that carbonate is part of the apatite structure

  3. Bewitchment, Biology, or Both: The Co-Existence of Natural and Supernatural Explanatory Frameworks across Development

    Science.gov (United States)

    Legare, Cristine H.; Gelman, Susan A.

    2008-01-01

    Three studies examined the co-existence of natural and supernatural explanations for illness and disease transmission, from a developmental perspective. The participants (5-, 7-, 11-, and 15-year-olds and adults; N = 366) were drawn from 2 Sesotho-speaking South African communities, where Western biomedical and traditional healing frameworks were…

  4. Shape and rotational co-existence of N=Z nuclei around A ≅ 72 region

    International Nuclear Information System (INIS)

    It was observed that the shape isomerism in N=Z nucleus which at the same time supports the predicted scenario of oblate prolate shape co-existence in the medium mass region. 72Kr seems to be one of the rarer nuclei with a rather pure oblate deformed ground state and the oblate-prolate shape mixing found in the Kr isotopes

  5. GMO neighbourhoods - will co-existence be a geographically realistic possibility?

    DEFF Research Database (Denmark)

    Qvist, H. Witt; Lundsgaard, H.; Brandt, Jesper

    2006-01-01

    In Denmark, there has been widespread opposition to the use of Genetically Modified Organisms (GMO’s) as a result of which rules have been developed relating to the co-existence of GM, conventionally and organically produced crops. This has been in the form of a spatially elaborated implementation...

  6. Valorization of horse manure through catalytic supercritical water gasification.

    Science.gov (United States)

    Nanda, Sonil; Dalai, Ajay K; Gökalp, Iskender; Kozinski, Janusz A

    2016-06-01

    The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss 70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products.

  7. Valorization of horse manure through catalytic supercritical water gasification.

    Science.gov (United States)

    Nanda, Sonil; Dalai, Ajay K; Gökalp, Iskender; Kozinski, Janusz A

    2016-06-01

    The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss 70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products. PMID:27067100

  8. Frequency of co-existence of dengue and malaria in patients presenting with acute febrile illness

    International Nuclear Information System (INIS)

    To find out the frequency of co-existence of malaria and dengue fever in patients presenting with acute febrile illness. Methods: The descriptive cross-sectional study was conducted at the Military Hospital Rawalpindi from June to November 2012. A total of 500 patients with complaint of acute febrile illness were selected after applying the inclusion and exclusion criteria. Preliminary data was collected on a pretested proforma. Blood samples of patients were tested for dengue serology and malaria parasite. Results were entered in respective proforma. Co-existence was considered present when a patient had both dengue serology and malaria parasite slide positive. SPSS 20 was used for data analysis. Result: Of the total, 349 (69.8%) were males and 151 (30.2%) females. Dengue serology was positive in 16 (3.2%); 81(16.2%) had malaria parasite slide positive; 403 (80.4%) had none of the two findings. Co-existence of both dengue and malaria was nil among the whole sample. In males, 67 (13.4%) had malaria, while 11 (2.2%) had dengue. In females, 14 (2.8%) had malaria, while 5 (1%) suffered from dengue fever. Conclusion: Co-existence of dengue and malaria was zero per cent in 500 patients visiting Military Hospital Rawalpindi. More studies shall be conducted to find out whether the reason of having zero per cent co-existence is that dengue or/and malaria epidemic did not occur in 2012 or whether there are some other factors involved. (author)

  9. Water Soluble Iron aminoclay for Catalytic Reduction of Nitrophenol

    Directory of Open Access Journals (Sweden)

    S. ANBU ANJUGAM VANDARKUZHALI

    2013-06-01

    Full Text Available Water soluble iron decorated phyllosilicate is synthesized through one pot sol-gel synthesis by a wet chemical method using NaBH4 as reducing agent. The as-synthesized nanocomposite is characterized by powder-XRD and TGA techniques. The morphology of the composite is obtained using HRSEM and HRTEM. The prepared nanocomposite is an efficient catalyst for the reduction of nitrophenol.

  10. Heterogeneous catalytic ozonation of ciprofloxacin in water with carbon nanotube supported manganese oxides as catalyst

    International Nuclear Information System (INIS)

    Highlights: ► Ciprofloxacin in water was degraded by heterogeneous catalytic ozonation. ► MnOx were supported on MWCNTs to serve as catalyst for ozonation. ► MnOx/MWCNT exhibited highly catalytic activity on ozonation of ciprofloxacin in water. ► MnOx/MWCNT resulted in effective antibacterial activity inhibition on ciprofloxacin. ► MnOx/MWCNT promoted the generation of hydroxyl radicals. - Abstract: Carbon nanotube-supported manganese oxides (MnOx/MWCNT) were used as catalysts to assist ozone in degrading ciprofloxacin in water. Manganese oxides were successfully loaded on multi-walled carbon nanotube surfaces by simply impregnating the carbon nanotube with permanganate solution. The catalytic activities of MnOx/MWCNT in ciprofloxacin ozonation, including degradation, mineralization effectiveness, and antibacterial activity change, were investigated. The presence of MnOx/MWCNT significantly elevated the degradation and mineralization efficiency of ozone on ciprofloxacin. The microbiological assay with a reference Escherichia coli strain indicated that ozonation with MnOx/MWCNT results in more effective antibacterial activity inhibition of ciprofloxacin than that in ozonation alone. The effects of catalyst dose, initial ciprofloxacin concentration, and initial pH conditions on ciprofloxacin ozonation with MnOx/MWCNT were surveyed. Electron spin resonance trapping was applied to assess the role of MnOx/MWCNT in generating hydroxyl radicals (HO·) during ozonation. Stronger 5,5-dimethyl-1-pyrroline-N-oxide–OH signals were observed in the ozonation with MnOx/MWCNT compared with those in ozonation alone, indicating that MnOx/MWCNT promoted the generation of hydroxyl radicals. The degradation of ciprofloxacin was studied in drinking water and wastewater process samples to gauge the potential effects of water background matrix on MnOx/MWCNT catalytic ozonation.

  11. Heterogeneous catalytic ozonation of ciprofloxacin in water with carbon nanotube supported manganese oxides as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Minghao, E-mail: suiminghao.sui@gmail.com [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xing, Sichu; Sheng, Li; Huang, Shuhang; Guo, Hongguang [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ciprofloxacin in water was degraded by heterogeneous catalytic ozonation. Black-Right-Pointing-Pointer MnOx were supported on MWCNTs to serve as catalyst for ozonation. Black-Right-Pointing-Pointer MnOx/MWCNT exhibited highly catalytic activity on ozonation of ciprofloxacin in water. Black-Right-Pointing-Pointer MnOx/MWCNT resulted in effective antibacterial activity inhibition on ciprofloxacin. Black-Right-Pointing-Pointer MnOx/MWCNT promoted the generation of hydroxyl radicals. - Abstract: Carbon nanotube-supported manganese oxides (MnOx/MWCNT) were used as catalysts to assist ozone in degrading ciprofloxacin in water. Manganese oxides were successfully loaded on multi-walled carbon nanotube surfaces by simply impregnating the carbon nanotube with permanganate solution. The catalytic activities of MnOx/MWCNT in ciprofloxacin ozonation, including degradation, mineralization effectiveness, and antibacterial activity change, were investigated. The presence of MnOx/MWCNT significantly elevated the degradation and mineralization efficiency of ozone on ciprofloxacin. The microbiological assay with a reference Escherichia coli strain indicated that ozonation with MnOx/MWCNT results in more effective antibacterial activity inhibition of ciprofloxacin than that in ozonation alone. The effects of catalyst dose, initial ciprofloxacin concentration, and initial pH conditions on ciprofloxacin ozonation with MnOx/MWCNT were surveyed. Electron spin resonance trapping was applied to assess the role of MnOx/MWCNT in generating hydroxyl radicals (HO{center_dot}) during ozonation. Stronger 5,5-dimethyl-1-pyrroline-N-oxide-OH signals were observed in the ozonation with MnOx/MWCNT compared with those in ozonation alone, indicating that MnOx/MWCNT promoted the generation of hydroxyl radicals. The degradation of ciprofloxacin was studied in drinking water and wastewater process samples to gauge the potential effects of water background matrix on

  12. [Beta-blockers usage in cardio-vascular diseases co-existing with COPD].

    Science.gov (United States)

    Walczak, Dorota; Kowal, Aneta; Jankowska, Renata

    2012-12-01

    Chronic obstructive pulmonary disease (COPD) is one of the most frequent chronic diseases. Slightly reversable and progressive decrease in airflow through the airways is characteristic for the disease. It has been brought up last years that COPD course influences not only pulmonary system status but also many co-existing diseases in the eldery, especially cardio-vascular diseases, such as: ischaemic heart disease, hypertension, heart arrythmias, heart infarction. Wide usage and established position in the treatment of cardio-vascular diseases have the antagonists of beta-adrenergic receptors (beta-blockers). The aim of this work was the combination of the studies results quoted in the literature about the usage of beta-blockers in cardiovascular diseases co-existing with COPD. Conclusions. Nowadays there are no unambiguous recommendations for the usage of beta-blocker in patients with COPD and the decision about including them into treatment depends on the individually estimated risk of complications. PMID:23437704

  13. Sinobronchial allergic aspergillosis with allergic bronchopulmonary aspergillosis: a less common co-existence

    Science.gov (United States)

    Upadhyay, Rashmi; Kant, Surya; Prakash, Ved; Saheer, S

    2014-01-01

    Allergic bronchopulmonary aspergillosis (ABPA) is an immunological pulmonary disorder that is characterised by a hyper-responsiveness of the airways to Aspergillus fumigatus. Although several other fungi may also present with similar clinical conditions, Aspergillus remains the most common fungal pathogen causing airway infections. Co-existence of ABPA with allergic Aspergillus sinusitis (AAS) is an uncommon presentation. The concept of one airway/one disease justifies the co-existence of ABPA with AAS, but it does not always hold true. We report a case of a 35-year-old woman who presented with symptoms suggestive of bronchial asthma. On further investigation, the radiological pattern showed fleeting shadows and CT scan showed central cystic bronchiectatic changes characteristic of ABPA. The nasal secretions were investigated for the presence of Aspergillus and were found to be positive. Hence a diagnosis of ABPA with AAS was established. The patient was treated with oral steroids and antifungal drugs. PMID:25371437

  14. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii.

    Science.gov (United States)

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Yap, George S

    2014-02-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of signal transducer and activator of transcription 6 (STAT6). Furthermore, this observation was recapitulated by IFN-γ and IL-4 treated bone marrow-derived macrophages in vitro. These results highlight the multi-functionality of macrophages as they respond to diverse microbial and endogenous stimuli. PMID:24083945

  15. Pancreatic insulinoma co-existing with gastric GIST in the absence of neurofibromatosis-1

    Directory of Open Access Journals (Sweden)

    O'Sullivan Brendan

    2009-02-01

    Full Text Available Abstract Background Gastrointestinal stromal tumours (GIST frequently occur in patients with neurofibromatosis type 1 (NF-1. It has been reported that GIST may co-exist with pancreatic endocrine tumors but this has only been in association with NF-1. Case presentation A 76 year old woman presented with a 12 month history of hypoglycaemia symptoms. Abdominal CT scan demonstrated a 13 mm insulinoma localized in the tail of her pancreas. She was commenced on diazoxide and later underwent surgery for enucleation of insulinoma when a small ( Conclusion This is the first case report of a pancreatic insulinoma co-existing with a GIST in a patient without NF-1. In addition, we make the first report of rapidly growing cystic GIST recurrence following resection of a primary GIST tumour.

  16. Co-existence of various clinical and histopathological features of mycosis fungoides in a young female.

    Science.gov (United States)

    Naeini, Farahnaz Fatemi; Soghrati, Mehrnaz; Abtahi-Naeini, Bahareh; Najafian, Jamshid; Rajabi, Parvin

    2015-01-01

    Mycosis fungoides is the most common type of cutaneous T-cell lymphoma (CTCL) and a rare disorder that typically affects older adults with erythematous scaling patches and plaques. Hypopigmented patches are a rare clinical variant of the disease. Granulomatous mycosis fungoides (GMF) is also a rare type of CTCL. No particular clinical criteria are available for the diagnosis of GMF, because of its variable presentations, and so the detection of GMF is primarily considered as a histopathological diagnosis. Rarely, a co-existence of more than one clinical or histopathological feature of mycosis fungoides may be present. To the best of our knowledge this is the first report of MF that shows the simultaneous co-existence of more than one clinical and histopathological variant of MF. We present a 29-year-old female with clinical presentations of both classic and hypopigmented mycosis fungoides (MF), and also the histopathological features of the classic and granulomatous types of the disease.

  17. Removal of dissolved oxygen from water using a Pd-resin based catalytic reactor

    Institute of Scientific and Technical Information of China (English)

    Wenxin SHI; Chongwei CUI; Liye ZHAO; Shuili YU; Xia YUN

    2009-01-01

    The removal of dissolved oxygen (DO) from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent. The effects of various operating conditions, such as hydrogen and water flow rates, height of the catalytic resin bed, temperature, pH value and nan time, on the removal of DO, had been studied extensively. The results shows that DO could be removed by the reactor from ppm to ppb levels at ambient temperature. Increases of temperature, H2gas rate and the height of the catalytic resin were helpful to improve the DO removal rate. The change of pH value fom 4 to 12 resulted in no effect on DO removal. Reaction time was the key factor to control the DO removal efficiency. Only when the reaction time was longer than 2.3 minutes under the experimental conditions, could a very low DO level be achieved.

  18. Co-existence with GM crops: grasses, clover and fodder beet

    OpenAIRE

    Jørgensen, R. B.; Løjtnant, C.; Andersen, N.S.; Andersen, B.A.

    2007-01-01

    Co-existence with GM crops: grasses, clover and fodder beet In 2006 the global cultivation of genetically modified crops increased with 13% and reached 102 million hectares. The GM crops cultivated are mainly soybean, maize, cotton and oilseed rape, but other modified crops are appearing, e.g. in 2006 herbicide tolerant alfalfa was commercialized in US. Also in Europe, GM crop cultivation is increasing with the largest areas in Rumania and Spain followed by Portugal, France, Germany, Czec...

  19. Pharmaceutical and Industrial Traits in Genetically Modified Crops: Co-Existence with Conventional Agriculture

    OpenAIRE

    Moschini, GianCarlo

    2006-01-01

    This paper discusses the implications of using genetically modified crops to biomanufacture pharmaceuticals and industrial compounds from the perspective of their co-existence with conventional agriculture. Such plant-made pharmaceuticals and plant-made industrial products rely on exciting scientific and technological breakthroughs and promise new opportunities for the agricultural sector, but they also entail novel risks. The management of the externalities and of the possible unintended eco...

  20. Unusual case of bancroftian filariasis co-existing with chronic myeloid leukemia

    OpenAIRE

    Mallika Kinger; Preeti Rihal Chakrabarti; Surabhi Sharma; Priyanka Kiyawat

    2014-01-01

    Filariasis, a tropical parasite infection, is a common public health problem in the Indian sub-continent. Occurrence of filariasis with chronic myeloid leukemia (CML) is unusual though there are case reports of leishmaniasis, malaria, and other vector-borne diseases seen in association with leukemias. Filariasis co-existing with CML has not been documented to the best of our knowledge and hence definitely needs a space in literature. We report an incidental finding of bancroftian filariasis i...

  1. Genetically modified and non-genetically modified food supply chains : co-existence and traceability

    OpenAIRE

    Bertheau, Yves

    2013-01-01

    In the European Union nations, and other countries including Japan, Australia and Malaysia, it is a legal requirement that food products containing genetically modified organism (GMO) materials are labelled as such in order that customers may make informed purchasing decisions. For manufacturers and consumers to be confident about these assertions, systems must be in place along the entire food chain which support the co-existence of GM and non GM materials whilst maintaining a strict segrega...

  2. Pancreatic insulinoma co-existing with gastric GIST in the absence of neurofibromatosis-1

    OpenAIRE

    O'Sullivan Brendan; Bramhall Simon; Alabraba Edward; Mahon Brinder; Taniere Philippe

    2009-01-01

    Abstract Background Gastrointestinal stromal tumours (GIST) frequently occur in patients with neurofibromatosis type 1 (NF-1). It has been reported that GIST may co-exist with pancreatic endocrine tumors but this has only been in association with NF-1. Case presentation A 76 year old woman presented with a 12 month history of hypoglycaemia symptoms. Abdominal CT scan demonstrated a 13 mm insulinoma localized in the tail of her pancreas. She was commenced on diazoxide and later underwent surge...

  3. Co-existence of Gel and Fluid Lipid Domains in Single-component Phospholipid Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Clare L [McMaster University; Barrett, M [McMaster University; Toppozini, L [McMaster University; Yamani, Zahra [Canadian Neutron Beam Centre, National Research Council, Chalk River Laboratorie; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Katsaras, John [ORNL; Fragneto, Giovanna [Institut Laue-Langevin (ILL); Rheinstadter, Maikel C [McMaster University

    2012-01-01

    Lateral nanostructures in membranes, so-called rafts, are believed to strongly influence membrane properties and functions. The experimental observation of rafts has proven difficult as they are thought to be dynamic structures that likely fluctuate on nano- to microsecond time scales. Using neutron diffraction we present direct experimental evidence for the co-existence of gel and fluid lipid domains in a single-component phospholipid membrane made of DPPC as it undergoes its main phase transition. The coherence length of the neutron beam sets a lower limit for the size of structures that can be observed. Neutron coherence lengths between 30 and 242A used in this study were obtained by varying the incident neutron energy and the resolution of the neutron spectrometer. We observe Bragg peaks corresponding to co-existing nanometer sized structures, both in out-of-plane and in-plane scans, by tuning the neutron coherence length. During the main phase transition, instead of a continuous transition that shows a pseudo-critical behavior, we observe the co-existence of gel and fluid domains.

  4. Cost of GMO-related co-existence and traceability systems in food production in Germany

    OpenAIRE

    Menrad, Klaus; Gabriel, Andreas; Zapilko, Marina

    2009-01-01

    In contrast to the increasing use of GM plants in world-wide agriculture, the acceptance of GM food is still low in the European Union (EU). In order to ensure freedom of choice for consumers and users of GM and non-GM products, GM food and feed products have to be labeled in case a tolerance threshold of 0.9 % is exceeded for EU authorized GMOs. This paper aims to quantify the cost of traceability and co-existence systems for GM food from the seed to the food level for sugar, wheat starch an...

  5. Respiratory Distress Secondary to Rhabdomyosarcoma of the Tongue and Co-existent Choanal Atresia.

    Science.gov (United States)

    Chatopadhayay, Rahul; Tiwari, Preeti; Gangopadhyay, A N; Pandey, Vaibhav

    2016-07-01

    Whilst rhabdomyosarcoma (RMS) is the third most common solid tumour in children, congenital RMS of the tongue is extremely rare and usually present as painless progressive mass since birth (Dagher and Helman in Oncologist 4:34-44, 1999; Childs and Goudy in Int J Pediatr Otorhinolaryngol 5:126-128, 2010). In neonates, presentation with respiratory distress is unexpected as neonates are preferential nasal breathers and restricted oral breathing due to tumour usually poses no problem. We herein report a case of rhabdomyosarcoma of the tongue with co-existent unilateral choanal atresia, presenting with respiratory distress. The baby developed upper respiratory tract infection following which developed severe respiratory distress. Airway symptoms were precipitated as there was combined obstruction of both the nostrils due to infection or adenoid enlargement and unilateral chonal atresia. Treatment of respiratory distress in the presence of RMS and bilateral nasal pathology must first prioritise the security of the airway, before taking a multi-factorial approach to the therapy of the lingual mass (Childs and Goudy in Int J Pediatr Otorhinolaryngol 5:126-128, 2010). This case illustrates the importance of vigilance with respect to co-existent nasal pathology, in order to avoid the occurrence of complete airway obstruction. We therefore feel that any diagnosis of lingual RMS should warrant a formal examination of both nasal cavities. PMID:27408448

  6. Spatiotemporal Co-existence of Female Thyroid and Breast Cancers in Hangzhou, China

    Science.gov (United States)

    Fei, Xufeng; Christakos, George; Lou, Zhaohan; Ren, Yanjun; Liu, Qingmin; Wu, Jiaping

    2016-06-01

    Thyroid and breast cancers (TC, BC) are common female malignant tumors worldwide. Studies suggest that TC patients have a higher BC risk, and vice versa. However, it has not been investigated quantitatively if there is an association between the space-time TC and BC incidence distributions at the population level. This work aims to answer this question. 5358 TC and 8784 BC (female) cases were diagnosed in Hangzhou (China, 2008–2012). Pearson and Spearman rank correlation coefficients of the TC and BC incidences were high, and their patterns were geographically similar. The spatiotemporal co-existence of TC and BC distributions was investigated using the integrative disease predictability (IDP) criterion: if TC-BC association is part of the disease mapping knowledge bases, it should yield improved space-time incidence predictions. Improved TC (BC) incidence predictions were generated when integrating both TC and BC data than when using only TC (BC) data. IDP consistently demonstrated the spatiotemporal co-existence of TC and BC distributions throughout Hangzhou (2008–2012), which means that when the population experiences high incidences of one kind of cancer attention should be paid to the other kind of cancer too. The strength of TC-BC association was measured by the IDP coefficients and incidence prediction accuracy.

  7. Development of an Experimental Model of Diabetes Co-Existing with Metabolic Syndrome in Rats.

    Science.gov (United States)

    Suman, Rajesh Kumar; Ray Mohanty, Ipseeta; Borde, Manjusha K; Maheshwari, Ujwala; Deshmukh, Y A

    2016-01-01

    Background. The incidence of metabolic syndrome co-existing with diabetes mellitus is on the rise globally. Objective. The present study was designed to develop a unique animal model that will mimic the pathological features seen in individuals with diabetes and metabolic syndrome, suitable for pharmacological screening of drugs. Materials and Methods. A combination of High-Fat Diet (HFD) and low dose of streptozotocin (STZ) at 30, 35, and 40 mg/kg was used to induce metabolic syndrome in the setting of diabetes mellitus in Wistar rats. Results. The 40 mg/kg STZ produced sustained hyperglycemia and the dose was thus selected for the study to induce diabetes mellitus. Various components of metabolic syndrome such as dyslipidemia {(increased triglyceride, total cholesterol, LDL cholesterol, and decreased HDL cholesterol)}, diabetes mellitus (blood glucose, HbA1c, serum insulin, and C-peptide), and hypertension {systolic blood pressure} were mimicked in the developed model of metabolic syndrome co-existing with diabetes mellitus. In addition to significant cardiac injury, atherogenic index, inflammation (hs-CRP), decline in hepatic and renal function were observed in the HF-DC group when compared to NC group rats. The histopathological assessment confirmed presence of edema, necrosis, and inflammation in heart, pancreas, liver, and kidney of HF-DC group as compared to NC. Conclusion. The present study has developed a unique rodent model of metabolic syndrome, with diabetes as an essential component. PMID:26880906

  8. A feasibility study of catalytic reduction method for tritium recovery from tritiated water

    International Nuclear Information System (INIS)

    Feasibility of catalytic reduction method for the application to the tritium recovery process in the fusion fuel cleanup system and the blanket tritium recovery system was studied by experimental work and the thermodynamic analysis. Reduction experiments of H2O vapor with Ar carrier were carried out under the following conditions: temperature; 350 -- 650 K, H2O vapor concentration in feed gas; 103 -- 104 ppm, mole ratio of CO to H2O; 1 -- 10, space velocity; 2 x 102 -- 2 x 104 hr-1. Catalyst was the mixture of CuO, ZnO and Cr2O3, which has been used as the catalyst for the water-gas shift reaction H2O(g) + CO(g) reversible H2(g) + CO2(g). Relations between the conversion factor for H2O vapor and the operating conditions such as temperature, feed composition and feed flow rate were obtained by the experiments. Catalytic reaction rate equation and the rate constants, which can be used for designing a practicable catalytic reduction bed, were also determined by the treatment of the second order reaction. Advantages of the tritium recovery system composed of the reduction bed and palladium diffusers were verified by the present experiments and the study of several tritium recovery systems. Very high recovery ratio will be obtained at low operation temperature by the systems. (author)

  9. A study on the photo catalytic decomposition reactions of organics dissolved in water (II)

    International Nuclear Information System (INIS)

    Experiments on aqueous TiO2 photo catalytic reaction of nitrogen containing organic compounds such as ethylamine, phenylhydrazine, pyridine, urea and EDTA were carried out. Based on the values calculated for the distribution of ionic species and atomic charge, the characteristics of their photo catalytic decomposition were estimated. It was shown that the decomposition characteristics was linearly proportional to nitrogen atomic charge value. On the other hand, the effects of aqueous pH, oxygen content and concentration on the TiO2 photo catalytic characteristics of EDTA, EDTA-Cu(II) and EDTA-Fe(III) were experimentally investigated. All EDTA systems were decomposed better in the pH range of 2.5-3.0 and with more dissolved oxygen. These results could be applied to construction of a process for removal of organic impurities dissolved in a source of system water, or for treatment of EDTA-containing liquid waste produced by a chemical cleaning in the domestic NPPs. (author)

  10. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 2 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  11. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 2 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  12. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 1 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  13. Electrochemical Synthesis of Mo2C Catalytical Coatings for the Water-Gas Shift Reaction

    Science.gov (United States)

    Kuznetsov, Sergey A.; Dubrovskiy, Anton R.; Rebrov, Evgeny V.; Schouten, Jaap C.

    2007-11-01

    The electroreduction of CO32- ions on a molybdenum cathode in a NaCl-KCl-Li2CO3 melt was studied by cyclic voltammetry. The electrochemical synthesis of Mo2C on molybdenum substrates has been performed at 1123 K for 7 h with a cathodic current density of 5 mA cm-2. If molybdenum carbide is present as a thin (ca. 500 nm) film on a molybdenum substrate (Mo2C/Mo), its catalytic activity in the water gas-shift reaction is enhanced by at least an order of magnitude compared to that of the bulk Mo2C phase.

  14. Vacuum distillation: vapor filtered-catalytic oxidation water reclamation system utilizing radioisotopes

    Science.gov (United States)

    Honegger, R. J.; Remus, G. A.; Kurg, E. K.

    1971-01-01

    The development of a functional model water reclamation system is discussed. The system produces potable water by distillation from the urine and respiration-perspiration condensate at the normal rate generated by four men. Basic processes employed are vacuum distillation, vapor filtration, vapor phase catalytic oxidation, and condensation. The system is designed to use four 75-watt isotope heaters for distillation thermal input, and one 45-watt isotope for the catalytic oxidation unit. The system is capable of collecting and storing urine, and provides for stabilizing the urine by chemical pretreatment. The functional model system is designed for operation in a weightless condition with liquid-vapor phase separators for the evaporator still, and centrifugal separators for urine collection and vapor condensation. The system provides for storing and dispensing reclaimed potable water. The system operates in a batch mode for 40 days, with urine residues accumulating in the evaporator. The evaporator still and residue are removed to storage and replaced with a fresh still for the next 40-day period.

  15. Familiality of Co-existing ADHD and Tic Disorders: Evidence from a Large Sibling Study

    Science.gov (United States)

    Roessner, Veit; Banaschewski, Tobias; Becker, Andreas; Buse, Judith; Wanderer, Sina; Buitelaar, Jan K.; Sergeant, Joseph A.; Sonuga-Barke, Edmund J.; Gill, Michael; Manor, Iris; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Steinhausen, Hans-Christoph; Faraone, Steven V.; Asherson, Philip; Rothenberger, Aribert

    2016-01-01

    Background: The association of attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) is frequent and clinically important. Very few and inconclusive attempts have been made to clarify if and how the combination of ADHD+TD runs in families. Aim: To determine the first time in a large-scale ADHD sample whether ADHD+TD increases the risk of ADHD+TD in siblings and, also the first time, if this is independent of their psychopathological vulnerability in general. Methods: The study is based on the International Multicenter ADHD Genetics (IMAGE) study. The present sub-sample of 2815 individuals included ADHD-index patients with co-existing TD (ADHD+TD, n = 262) and without TD (ADHD–TD, n = 947) as well as their 1606 full siblings (n = 358 of the ADHD+TD index patients and n = 1248 of the ADHD-TD index patients). We assessed psychopathological symptoms in index patients and siblings by using the Strength and Difficulties Questionnaire (SDQ) and the parent and teacher Conners' long version Rating Scales (CRS). For disorder classification the Parental Account of Childhood Symptoms (PACS-Interview) was applied in n = 271 children. Odds ratio with the GENMOD procedure (PROCGENMOD) was used to test if the risk for ADHD, TD, and ADHD+TD in siblings was associated with the related index patients' diagnoses. In order to get an estimate for specificity we compared the four groups for general psychopathological symptoms. Results: Co-existing ADHD+TD in index patients increased the risk of both comorbid ADHD+TD and TD in the siblings of these index patients. These effects did not extend to general psychopathology. Interpretation: Co-existence of ADHD+TD may segregate in families. The same holds true for TD (without ADHD). Hence, the segregation of TD (included in both groups) seems to be the determining factor, independent of further behavioral problems. This close relationship between ADHD and TD supports the clinical approach to carefully assess ADHD in any case

  16. Azathioprine Induced Pancreatitis in a Patient with Co-Existing Autoimmune Pancreatitis and Hepatitis

    Directory of Open Access Journals (Sweden)

    Preethi GK Venkatesh

    2011-05-01

    Full Text Available Context Azathioprine induced pancreatitis usually runs a benign self limited course with rapid disappearance of signs and symptoms upon with drawl of the drug. Azathioprine is used in treating relapses in patients with autoimmune pancreatitis and maintenance of remission in autoimmune hepatitis. Acute pancreatitis complicated by symptomatic pseudocysts requiring drainage is not usually associated with drug induced pancreatitis. The risk of azathioprine use in patients with underlying disease of pancreas including autoimmune pancreatitis is unclear. Case report We report here a case of an African American patient with co-existing autoimmune pancreatitis and autoimmune hepatitis who developed azathioprine induced acute pancreatitis complicated by a large symptomatic pseudocyst compressing the duodenum requiring a cystoduodenostomy. Conclusions Future studies to investigate the risk of azathioprine induced pancreatitis in the presence of underlying disease of the pancreas including autoimmune pancreatitis are required to further understand the safety of azathioprine in this sub group of patients.

  17. Co-existence of Insulin Dependent Diabetes and Graves’ Disease in a Patient with Down Syndrome

    Directory of Open Access Journals (Sweden)

    Ayşe Kubat Üzüm

    2010-05-01

    Full Text Available Down’s syndrome is the most common genetic disorder. It is well established that there is an increased risk of autoimmune endocrine diseases in Down’s syndrome. Defect of a gene located on chromosome 21q22.3 causes autoimmune polyglandular syndrome type 1 and this might be related with susceptibility to autoimmune diseases in patients with Down’s syndrome. We reported a 20-year-old male with Down’s syndrome who was brought to emergency room by his family and had a diagnose of diabetic ketoacidosis and Graves’ disease. Underlying mechanisms in co-existing of autoimmune diseases in Down’s syndrome, management of such patients and the importance of making the family to be aware of the symptoms of possible subsequent components of the autoimmune polyglandular syndrome are discussed. Turk Jem 2010; 14: 17-9

  18. Evidence for Shape Co-existence at medium spin in 76Rb

    CERN Document Server

    Wadsworth, R; Carlsson, B G; Ma, Hai-Liang; Davies, P J; Andreoiu, C; Austin, R A E; Carpenter, M P; Dashdorj, D; Freeman, S J; Garrett, P E; Greene, J; Görgen, A; Jenkins, D G; Johnston-Theasby, F; Joshi, P; Macchiavelli, A O; Moore, F; Mukherjee, G; Reviol, W; Sarantites, D G; Seweryniak, D; Svensson, C E; Valiente-Dobón, J J

    2011-01-01

    Four previously known rotational bands in 76Rb have been extended to moderate spins using the Gammasphere and Microball gamma ray and charged particle detector arrays and the 40Ca(40Ca,3pn) reaction at a beam energy of 165 MeV. The properties of two of the negative-parity bands can only readily be interpreted in terms of the highly successful Cranked Nilsson-Strutinsky model calculations if they have the same configuration in terms of the number of g9/2 particles, but they result from different nuclear shapes (one near-oblate and the other near-prolate). These data appear to constitute a unique example of shape co-existing structures at medium spins.

  19. A rare case of breast carcinoma co-existing with axillary mantle cell lymphoma

    Directory of Open Access Journals (Sweden)

    Scally John

    2003-12-01

    Full Text Available Abstract Background Mantle cell lymphoma (MCL is a rare variety of non-Hodgkin's lymphoma which originates from CD5+ B-cell population in the mantle zones of lymphoid follicles. Coexistence of such tumours in the axillary lymph nodes with invasive breast cancers without prior history of adjuvant chemotherapy or radiotherapy has not been previously reported in literature. Case report We report a rare case of breast cancer co-existing with stage I mantle cell lymphoma of the ipsilateral axillary lymph node detected fortuitously by population screening. Conclusion Though some studies have tried to prove breast carcinomas and lymphomas to share a common molecular or viral link, more research needs to be done to establish whether such a link truly exists.

  20. Co-existing ericaceous plant species in a subarctic mire community share fungal root endophytes

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Olsrud, Maria; Michelsen, Anders

    2010-01-01

    the fungal composition in roots of co-existing ericaceous plants is scarce. In the present paper, the fungal community in roots of four ericaceous plant species, Empetrum hermaphroditum, Andromeda polifolia, Vaccinium uliginosum and Vaccinium vitis-idaea which often dominate subarctic heaths and mires......During the last decade, culture-independent identification tools have widened our knowledge of fungi colonizing ericaceous roots including ericoid mycorrhizal fungi. One focal interest has been to identify fungi, which simultaneously can establish ericoid and ectomycorrhiza, while knowledge about......, was studied. From each of these plants, in each of five plots, clone libraries were established using fungal specific ITS-PCR followed by cloning, PCR–RFLP and sequencing. The clone libraries were dominated by potential ericoid mycorrhizal fungi, particularly Rhizoscyphus ericae, fungi belonging...

  1. Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios

    OpenAIRE

    L. Polak; Kaller, O.; L. Klozar; J. Sebesta; T. Kratochvil

    2014-01-01

    The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks ...

  2. First-principles quantum-mechanical investigations: The role of water in catalytic conversion of furfural on Pd(111)

    Science.gov (United States)

    Xue, Wenhua; Borja, Miguel Gonzalez; Resasco, Daniel E.; Wang, Sanwu

    2015-03-01

    In the study of catalytic reactions of biomass, furfural conversion over metal catalysts with the presence of water has attracted wide attention. Recent experiments showed that the proportion of alcohol product from catalytic reactions of furfural conversion with palladium in the presence of water is significantly increased, when compared with other solvent including dioxane, decalin, and ethanol. We investigated the microscopic mechanism of the reactions based on first-principles quantum-mechanical calculations. We particularly identified the important role of water and the liquid/solid interface in furfural conversion. Our results provide atomic-scale details for the catalytic reactions. Supported by DOE (DE-SC0004600). This research used the supercomputer resources at NERSC, of XSEDE, at TACC, and at the Tandy Supercomputing Center.

  3. A supramolecular ruthenium macrocycle with high catalytic activity for water oxidation that mechanistically mimics photosystem II

    Science.gov (United States)

    Schulze, Marcus; Kunz, Valentin; Frischmann, Peter D.; Würthner, Frank

    2016-06-01

    Mimicking the ingenuity of nature and exploiting the billions of years over which natural selection has developed numerous effective biochemical conversions is one of the most successful strategies in a chemist's toolbox. However, an inability to replicate the elegance and efficiency of the oxygen-evolving complex of photosystem II (OEC-PSII) in its oxidation of water into O2 is a significant bottleneck in the development of a closed-loop sustainable energy cycle. Here, we present an artificial metallosupramolecular macrocycle that gathers three Ru(bda) centres (bda = 2,2‧-bipyridine-6,6‧-dicarboxylic acid) that catalyses water oxidation. The macrocyclic architecture accelerates the rate of water oxidation via a water nucleophilic attack mechanism, similar to the mechanism exhibited by OEC-PSII, and reaches remarkable catalytic turnover frequencies >100 s–1. Photo-driven water oxidation yields outstanding activity, even in the nM concentration regime, with a turnover number of >1,255 and turnover frequency of >13.1 s–1.

  4. A supramolecular ruthenium macrocycle with high catalytic activity for water oxidation that mechanistically mimics photosystem II.

    Science.gov (United States)

    Schulze, Marcus; Kunz, Valentin; Frischmann, Peter D; Würthner, Frank

    2016-06-01

    Mimicking the ingenuity of nature and exploiting the billions of years over which natural selection has developed numerous effective biochemical conversions is one of the most successful strategies in a chemist's toolbox. However, an inability to replicate the elegance and efficiency of the oxygen-evolving complex of photosystem II (OEC-PSII) in its oxidation of water into O2 is a significant bottleneck in the development of a closed-loop sustainable energy cycle. Here, we present an artificial metallosupramolecular macrocycle that gathers three Ru(bda) centres (bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) that catalyses water oxidation. The macrocyclic architecture accelerates the rate of water oxidation via a water nucleophilic attack mechanism, similar to the mechanism exhibited by OEC-PSII, and reaches remarkable catalytic turnover frequencies >100 s(-1). Photo-driven water oxidation yields outstanding activity, even in the nM concentration regime, with a turnover number of >1,255 and turnover frequency of >13.1 s(-1).

  5. Session 6: Water depollution from aniline and phenol by air oxidation and adsorptive-catalytic oxidation in liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Dobrynkin, N.M.; Batygina, M.V.; Noskov, A.S. [Boreskov Institute of Catalysis of Siberian Branch of Russian Academy of Sciences, Pr. Ak. Lavrentieva (Russian Federation)

    2004-07-01

    This paper is devoted to development of carbon catalysts and application of catalytic wet air oxidation for deep cleaning of polluted waters. The described catalysts and method are solving the problem of development environmentally reliable method for fluids treatment and allow carrying out the adsorption of pollutants on carbon CAPM (catalytically active porous material) with following regeneration of the CAPM without the loss of adsorptive qualities. The experiments have shown a principal capability simultaneously to use carbon CAPM as adsorbent and either as catalyst, or as a catalyst support for oxidation of aniline and phenol in water solutions. (authors)

  6. Effect of zinc and copper additions on catalytic response of noble metal alloyed 304 SS in high temperature water

    International Nuclear Information System (INIS)

    The effect of zinc (Zn) and copper (Cu) additions on the catalytic behavior of noble metal alloyed 304 stainless steel (SS) in 288 C water understoichiometric excess hydrogen was studied. It was observed that an increase in the Zn or Cu content of the water increased the electrochemical corrosion potential (ECP) of noble metal alloyed 304 SS by ∼ 30 to 50 mV and decreased the recombination efficiency of oxygen (O2)and hydrogen (H2) by ∼ 10%. The change in the ECP and recombination rate was correlated with incorporation of zinc and copper in the oxide film, which, by covering catalytic sites, would alter the redox reaction rate

  7. Critical Issues in the Identification of Gifted Students With Co-Existing Disabilities

    Directory of Open Access Journals (Sweden)

    Barbara Jackson Gilman

    2013-09-01

    Full Text Available Federal law ensures all students with disabilities the right to a Free, Appropriate Public Education (FAPE. However, current policies governing a student’s eligibility for services may contribute to the underidentification of gifted children with co-existing disabilities—the Twice-Exceptional. The emphasis on below-grade-level (or lower performance, without regard to ability or potential weaknesses, misses twice-exceptional students. Those who perform at grade level, by using advanced conceptual abilities and hard work to compensate, may still require interventions and accommodations to manage increasing educational demands. Otherwise, college and even high school graduation may be out of reach. This article reviews changing laws and policies, explores case studies of twice-exceptional students missed, and examines the diagnosis of twice-exceptionality through comprehensive assessment. Appropriate best practices for the identification of twice-exceptional learners, maintenance of their civil rights, and provision of FAPE are offered for educators, parents, advocates, and legislators as federal, state, and district laws/policies evolve.

  8. The clinicopathologic differences in papillary thyroid carcinoma with or without co-existing chronic lymphocytic thyroiditis.

    Science.gov (United States)

    Yoon, Yeo-Hoon; Kim, Hak Joon; Lee, Jin Woo; Kim, Jin Man; Koo, Bon Seok

    2012-03-01

    The goal of this study is to determine the clinicopathologic differences in patients with papillary thyroid carcinoma (PTC) with or without chronic lymphocytic thyroiditis (CLT). We reviewed the medical records of 195 consecutive PTC patients who underwent total thyroidectomy and bilateral central lymph node dissection from April 2008 to March 2010. The differences in clinicopathologic factors, such as age, gender, size of primary tumor, perithyroidal invasion, lymphovascular invasion, capsular invasion, and central lymph node (CLN) metastasis, were analyzed in PTC patients with or without CLT. Among 195 patients, 56 (28.7%) had co-existing CLT. Patients with CLT had the following characteristics as compared to patients without CLT: significantly younger, female predominance, smaller tumor size, and lower incidence of capsular invasion (p = 0.038, 0.006, 0.037, and 0.026, respectively). Also, patients with CLT (12.5%) had a significantly lower incidence of CLN metastases than patients without CLT (28.1%; p = 0.025) based on univariate analysis. Moreover, multivariate analysis showed that younger age (p = 0.042, odds ratio = 1.033) and female gender (p = 0.012, odds ratio = 6.865) are independent clinical factors in patients with CLT compared to patients without CLT. CLT was shown to be commonly associated with PTC. Compared to patients with PTC without CLT, patients with CLT were younger with a female predominance, which are the most important and well-known prognostic variables for thyroid cancer mortality. PMID:21822854

  9. Co-existence of dual intracranial pathology clinical relevance of proton MRS.

    Directory of Open Access Journals (Sweden)

    Tripathi R

    2000-10-01

    Full Text Available The co-existence of neuro-cysticercosis (NCC and intracranial neoplasm in an individual is a rare entity. Atypical presentation of cerebral cysticercosis may mimic glioma, metastasis, cerebral abscess or vice versa. The dual existence of these two lesions have led to several postulates which may have clinical impact in due course of time i.e. NCC as an oncogenetic factor for glioma or similarity of antigen found in glioma and NCC etc. An adequate management of such cases poses a challenge to both imageologists as well as clinicians. Thus, a proper diagnostic evaluation is essential for successful management of such cases. MR spectroscopy (MRS, although still a clinical research tool, may be extremely useful for exclusion or confirmation of neoplastic lesions in such a clinical scenario. The findings of MRS in collaboration with imaging parameters may increase the diagnostic yield of a MR investigation. The authors encountered five cases of dual intracranial pathologies i.e. neurocysticercosis and glioma. MR spectroscopy was useful to arrive at a definitive diagnosis in such a situation.

  10. An FTIR study on the catalytic effect of water molecules on the reaction of CO successive hydrogenation at 3 K

    International Nuclear Information System (INIS)

    Graphical abstract: This work highlights a selective catalytic action of water molecules on the reaction of CO hydrogenation at 3 K. Research highlights: → [CO/H2O] and [H/H2] are coinjected at 3 K. → H2 molecules condense rapidly at 3 K and screen the reaction mostly at the 1st step. → The observed catalytic effects on CO hydrogenation increase with water concentration. - Abstract: The reaction of successive CO hydrogenation has been performed at 3 K by coinjecting CO molecules and H atoms. The concentration of CO has been progressively reduced and replaced by water molecules to create two different environments where CO and H2O are successively the dominant species in the binary (CO/H2O) mixture. The catalytic effect of water molecules on CO hydrogenation appears clearly since the early times of the experiment and evolves with the formation of the CO/H2/H2O mixed-matrix. The process of CO hydrogenation, initially frozen at the first step of the reaction, is brought to completion through water influence. Water molecules guide the reaction toward the formation of CH3OH and promote different reaction steps depending on water concentration. Water molecules increase the probability of reactive to encounter H atoms either physically, by introducing structural changes in the matrix, or chemically, by raising the number of chemical pathways.

  11. Kinetic and Phase Behaviors of Catalytic Cracking Dry Gas Hydrate in Water-in-Oil Emulsion

    Institute of Scientific and Technical Information of China (English)

    MA Qinglan; HUANG Qiang; CHEN Guangjin; WANG Xiulin; SUN Changyu; YANG Lanying

    2013-01-01

    The systematic experimental studies were performed on the hydrate formation kinetics and gas-hydrate equilibrium for a simulated catalytic cracking gas in the water-in-oil emulsion.The effect of temperature,pressure and initial gas-liquid ratio on the hydrate formation was studied,respectively.The data were obtained at pressures ranging from 3.5 to 5 MPa and temperatures from 274.15 to 277.15 K.The results showed that hydrogen and methane can be separated from the C2+ fraction by forming hydrate at around 273.15 K which is much higher temperature than that of the cryogenic separation method,and the hydrate formation rate can be enhanced in the water-in-oil emulsion compared to pure water.The experiments provided the basic data for designing the industrial process,and setting the suitable operational conditions.The measured data of gas-hydrate equilibria were compared with the predictions by using the Chen-Guo hydrate thermodynamic model.

  12. Transovarial Transmission of Co-Existing Orientia tsutsugamushi Genotypes in Laboratory-Reared Leptotrombidium imphalum.

    Science.gov (United States)

    Takhampunya, Ratree; Tippayachai, Bousaraporn; Korkusol, Achareeya; Promsathaporn, Sommai; Leepitakrat, Surachai; Sinwat, Warattaya; Schuster, Anthony L; Richards, Allen L

    2016-01-01

    The co-evolution of Orientia tsutsugamushi and its vector/host Leptotrombidium mites is important for this bacterium to survive and exist in its environment. The data in this study demonstrated that O. tsutsugamushi has adapted to take advantage of the parasitic nature of the host's larval stage and thus increase its chance of transmission to a vertebrate host and potentially to other vector mites by increasing its density at the time of transmission. Our data demonstrated that during the larval stage the density of O. tsutsugamushi was at its highest level compared to other life stages (Kruskal-Wallis, p transmission from the Leptotrombidium imphalum, lines Li-3 and Li-5. No sequence difference of 56-kDa TSA gene (variable domain I-III, 765 bp) was observed between the UT302-like genotype found in mothers and their offspring (100% identity). However, one or two nonsynonymous mutations in the 56-kDa TSA gene were observed in the Karp-like genotypes found in the F1 offspring with a percent difference ranging from 0.13 to 0.26 for nucleotide sequences and from 0.39 to 0.78 for amino acid sequences. Additionally, the composition of co-existing O. tsutsugamushi genotypes was maintained in L. imphalum lines through transsovarial and transstadial transmission processes; however, the proportion of these genotypes in each stage varied (larva, nymph, adult). These results show some of the key characteristics of O. tsutsugamushi maintenance within and transmission among its vector/host L. imphalum.

  13. Mechanism of photo catalytic degradation of Brilliant Blue colorant in water suspension with TiO{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, J.A.; Gonzalez-Hernandez, J. [CIMAV, Complejo Industrial Chihuahua, 3110, Chihuahua (Mexico); Perez-Robles, J.F.; Vorobiev, P.; Vorobiev, Y.V.; Garcia, A.G. [Unidad Queretaro del CINVESTAV-IPN, Libramiento Norponiente 2000, 76230 Queretaro (Mexico)

    2011-06-15

    Water purification by photo catalytic decomposition of Brilliant Blue colorant in water suspension was studied. This work presents experimental and theoretical results in which the mechanism is discussed of decomposition of an organic colorant's molecule. In theoretical part, a calculation of the energy levels of the molecule and its parts derived in decomposition process based on modified FEMO modeling confirm the mechanism proposed (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Photo-catalytic reactors for in-building grey water reuse. Comparison with biological processes and market potential

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, B.; Murray, C.; Diaper, C.; Parsons, S.A.; Jeffrey, P. [School of Water Sciences, Cranfield Univ., Cranfield, Bedfordshire (United Kingdom); Bedel, C. [Dept. of Industrial Process, National Inst. of Applied Sciences (France); Centeno, C. [Dept. of the Faculty of Engineering, Univ. of Santo Tomas, Manila (Philippines)

    2003-07-01

    Photo catalytic reactors potentially have a market in the reuse of grey water as they do not suffer from problems associated with toxic shocks and can be compact. The process is dependant upon the ratio of TOC to TiO{sub 2} concentration such that a greater proportion of the feed is degraded when either are increased. Economic assessment of grey water recycling showed both scale of operation and regional location to be the two most important factors in deciding the financial acceptability of any reuse technology. Overall the assessment suggested that photo catalytic oxidation (PCO) technology was suitable for grey water recycling and that the technology should be marketed at large buildings such as residential accommodation and offices. (orig.)

  15. Phenomenological modeling and study of a catalytic membrane reactor for water detritiation

    International Nuclear Information System (INIS)

    Tritium is produced in light and heavy water reactor fuel by ternary fission or neutron activation. This by-product is used as fuel in fusion fuel reactors such as JET in Culham or ITER in Cadarache (France). The growing interest of this research area will make the tritium fluxes increase; it is then worth addressing the question of its future whether it will be used or flushed out from liquid and gaseous effluents or waste. This thesis studies the recovery of tritium as fuel for fusion machines by means of packed bed membrane reactor (PBMR). Such a reactor combines catalytic conversion of tritiated water thanks to isotope exchange with hydrogen according to the reversible reaction Q2O+H2↔H2O+Q2 (Q=H,D or T) and selective permeation of Q2 through Pd-based membrane. In fact, palladium has the ability to bond with hydrogen isotopes, creating a selective permeation barrier. In the PBMR, thanks to the reaction products withdrawal, these permeation fluxes drive the heavy water conversion rate, to higher values than those reached in conventional fixed bed reactors (Le Chatelier's law). In order to study PBMRs, the CEA has built a test bench, using deuterium instead of tritium, allowing the analysis of their conversion and separation performances at the laboratory scale. An in-house method has been developed to determine simultaneously hydrogen and water isotopologues content by mass spectrometer analysis. It was experimentally shown that the activity of Ni-based catalyst used in this study was sufficient to allow the isotope exchange reactions to reach their thermodynamic equilibrium in a very short time. In addition, hydrogen permeation flux was shown to follow a Richardson's law. Sensitivity studies performed on the PBMR's main operating parameters revealed that its global performance (i.e. de-deuteration factor) increases with the temperature, the transmembrane pressure difference, the sweep gas flow rate and the residence time in the catalyst

  16. Reactivity of Ir(III) carbonyl complexes with water: alternative by-product formation pathways in catalytic methanol carbonylation

    OpenAIRE

    Haynes, A.; Elliott, P. I. P.; Haak, S; Meijer, A.J.H.M.; Sunley, G.J

    2013-01-01

    The reactions of water with a number of iridium(III) complexes relevant to the mechanism for catalytic methanol carbonylation are reported. The iridium acetyl, [Ir(CO)2I3(COMe)]−, reacts with water under mild conditions to release CO2 and CH4, rather than the expected acetic acid. Isotopic labeling and kinetic experiments are consistent with a mechanism involving nucleophilic attack by water on a terminal CO ligand of [Ir(CO)2I3(COMe)]− to give an (undetected) hydroxycarbonyl spec...

  17. Polyurethane foams doped with stable silver nanoparticles as bactericidal and catalytic materials for the effective treatment of water

    OpenAIRE

    Domènech Garcia, Berta; Ziegler Benítez, Kharla; Vigués Frantzen, Núria; Olszewski, Wojciech; Marini, Carlo; Mas Gordi, Jordi; Muñoz Tapia, Maria; Muraviev, Dmitri N; Macanás de Benito, Jorge

    2016-01-01

    The development of reusable dual-purpose nanocomposite foams for catalytic and bactericidal water treatment is reported. Small non-aggregated silver nanoparticles were made using Intermatrix Synthesis inside a polyurethane foam, which was chosen as a suitable polymeric matrix due to its high chemical and mechanical stability and industrial applicability. The antibacterial activity of the obtained nanocomposites was evaluated against suspensions of Gram-negative bacteria (E. coli), showing ide...

  18. Fluorescence spectroscopic characterization of DOM fractions isolated from a filtered river water after ozonation and catalytic ozonation.

    Science.gov (United States)

    Zhang, Tao; Lu, Jinfeng; Ma, Jun; Qiang, Zhimin

    2008-03-01

    Fluorescence spectra were applied to investigate the structural changes of four dominant dissolved natural organic matter (DOM) fractions of a filtered river water before and after ozonation and catalytic ozonation. The ozonation and catalytic ozonation with synthetic goethite (FeOOH) and cerium dioxide (CeO(2)) were carried out under normal conditions, i.e. pH 7, reaction time of 10 min, and ozone/DOC ratio of about 1. The fluorescence spectra were recorded at both excitation-emission matrix (EEM) and synchronous scanning modes. EEM results reveal that ozonation of these DOM fractions causes a significant decrease of the aromaticity of humic-like structures and an increase of electron withdrawing groups, e.g., carboxylic groups. The catalysts can further improve the destruction of the humic-like structures in catalytic ozonation. Synchronous spectra reveal that ozonation of hydrophobic acid and hydrophilic acid (HIA) yields a significant amount of by-products with low aromaticity and low molecular weight. Catalytic ozonation enhances substantially the formation of these by-products from HIA and improves the destruction of highly polycyclic aromatic structures for all examined DOM fractions. PMID:18190948

  19. Catalytic hydrodechlorination of PCDD/Fs from condensed water with Pd/γ-Al2O3.

    Science.gov (United States)

    Liu, Mei-Chen; Chang, Shu-Hao; Chang, Moo-Been

    2016-07-01

    A continuous pyrolysis system (CPS) with effective air pollution control devices (APCDs) is designed and constructed to remediate the soil containing high-concentration PCDD/Fs. The quench tower of the APCDs system can capture the pollutants of high boiling points from the flue gas of CPS and produces condensed water of high PCDD/Fs concentration (16-44 ng I-TEQ/L), and needs further treatment. First, the result of activated carbon adsorption test displays the PCDD/Fs toxicity concentration of effluents meet the regulatory standards as the liquid to solid ratio is controlled at 3: 1. However, large amount of activated carbon need to achieve the high removal efficiency leads to high cost, so catalytic hydrodechlorination technology with Pd/Al2O3 as catalyst is applied to treat the condensed water. The PCDD/Fs mass removal efficiency achieved without the reducing agent is 53.21% with the operating time of 180 min. As 5% reducing agent (methanol) is added, the removal efficiency increases to 71.86%. In addition, to better understand the differences between molecular hydrogen and hydrogen donor, the condensed water was pre-aerated with hydrogen and catalytic hydrodechlorination test with palladium as catalyst was conducted. The results show that the PCDD/Fs mass removal efficiency increases to 97.34% with the operating time of 180 min, demonstrating the high PCDD/Fs removal efficiency of catalytic hydrodechlorination. PMID:27088535

  20. Dynamical co-existence of excitons and free carriers in perovskite probed by density-resolved fluorescent spectroscopic method

    CERN Document Server

    Wang, Wei; Wang, Xiangyuan; Lv, Yanping; Wang, Shufeng; Wang, Kai; Shi, Yantao; Xiao, Lixin; Chen, Zhijian; Gong, Qihuang

    2016-01-01

    Using transient fluorescent spectra at time-zero, we develop a density-resolved fluorescent spectroscopic method for investigating photoproducts in CH3NH3PbI3 perovskite and related photophysics. The density dependent dynamical co-existence of excitons and free carriers over a wide density range is experimentally observed for the first time. The exciton binding energy (EB) and the effective mass of electron-hole pair can be estimated based on such co-existence. No ionic polarization is found contributing to photophysical behavior. It also solves the conflict between the large experimentally measured EB and the small predicted values. The spectroscopic method also helps to detect the true free carrier density under continuous illumination without the interference of ionic conductivity. Our methods and results profoundly enrich the study and understanding of the photophysics in perovskite materials for photovoltaic applications.

  1. Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios

    Directory of Open Access Journals (Sweden)

    L. Polak

    2014-04-01

    Full Text Available The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks (from GSM to LTE and digital terrestrial television broadcasting (DVB systems. For all of these measurements and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work package WP5 in the ENIAC JU project “Agile RF Transceivers and Front-Ends for Future Smart Multi-Standard Communications Applications (ARTEMOS”.

  2. Patchiness and co-existence of indigenous and invasive mussels at small spatial scales: the interaction of facilitation and competition.

    Directory of Open Access Journals (Sweden)

    Johan Erlandsson

    Full Text Available Ecological theory predicts that two species with similar requirements will fail to show long-term co-existence in situations where shared resources are limiting, especially at spatial scales that are small relative to the size of the organisms. Two species of intertidal mussels, the indigenous Perna perna and the invasive Mytilus galloprovincialis, form mixed beds on the south coast of South Africa in a situation that has been stable for several generations of these species, even though these populations are often limited by the availability of space. We examined the spatial structure of these species where they co-exist at small spatial scales in the absence of apparent environmental heterogeneity at two sites, testing: whether conspecific aggregation of mussels can occur (using spatial Monte-Carlo tests; the degree of patchiness (using Korcak B patchiness exponent, and whether there was a relationship between percent cover and patchiness. We found that under certain circumstances there is non-random conspecific aggregation, but that in other circumstances there may be random distribution (i.e. the two species are mixed, so that spatial patterns are context-dependent. The relative cover of the species differed between sites, and within each site, the species with higher cover showed low Korcak B values (indicating low patchiness, i.e. the existence of fewer, larger patches, while the less abundant species showed the reverse, i.e. high patchiness. This relationship did not hold for either species within sites. We conclude that co-existence between these mussels is possible, even at small spatial scales because each species is an ecological engineer and, while they have been shown to compete for space, this is preceded by initial facilitation. We suggest that a patchy pattern of co-existence is possible because of a balance between direct (competitive and indirect (facilitative interactions.

  3. Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article

    Science.gov (United States)

    Chao, Che-Yung; Battat, Robert; Al Khoury, Alex; Restellini, Sophie; Sebastiani, Giada; Bessissow, Talat

    2016-01-01

    Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes. PMID:27678354

  4. Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article.

    Science.gov (United States)

    Chao, Che-Yung; Battat, Robert; Al Khoury, Alex; Restellini, Sophie; Sebastiani, Giada; Bessissow, Talat

    2016-09-14

    Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes.

  5. Effect of Water Vapour on the Acidity of ZSM-5Zeolite Used for Catalytic Cracking of Naphtha to Manufacture Ethylene and Propylene

    Institute of Scientific and Technical Information of China (English)

    Ma Guangwei; Xiao Jingxian; ZhangHuining; Xie Zaiku

    2008-01-01

    The change in acidity of the ZSM-5 zeolite was investigated after it was treated with water vapour,and its capability on ammonia adsorption was also studied after having adsorbed water vapour.The effect of water vapour on products distribution was studied during catalytic cracking of naphtha,the changes in the adsorption ability and catalytic performance of the ZSM-5 zeolite was investigated after the catalyst was loaded with phosphorus species.These results all indicated that water vapour could reduce the acid strength and acid density of ZSM-5 zeolite and affect the capability of ZSM-5 on adsorption of gases,therefore the activated energy contributed by the ZSM-5 zeolite to the catalytic cracking reaction would be low to prevent the feedstock from deepened catalytic cracking and coke formation.

  6. Principles of water oxidation and O2-based hydrocarbon transformation by multinuclear catalytic sites

    Energy Technology Data Exchange (ETDEWEB)

    Musaev, Djamaladdin G [Chemistry, Emory University; Hill, Craig L [Chemistry, Emory University; Morokuma, Keiji [Chemistry, Emory University

    2014-10-28

    Abstract The central thrust of this integrated experimental and computational research program was to obtain an atomistic-level understanding of the structural and dynamic factors underlying the design of catalysts for water oxidation and selective reductant-free O2-based transformations. The focus was on oxidatively robust polyoxometalate (POM) complexes in which a catalytic active site interacts with proximal metal centers in a synergistic manner. Thirty five publications in high-impact journals arose from this grant. I. Developing an oxidatively and hydrolytically stable and fast water oxidation catalyst (WOC), a central need in the production of green fuels using water as a reductant, has proven particularly challenging. During this grant period we have designed and investigated several carbon-free, molecular (homogenous), oxidatively and hydrolytically stable WOCs, including the Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]·25H2O (1) and [Co4(H2O)2(α-PW9O34)2]10- (2). Although complex 1 is fast, oxidatively and hydrolytically stable WOC, Ru is neither abundant nor inexpensive. Therefore, development of a stable and fast carbon-free homogenous WOC, based on earth-abundant elements became our highest priority. In 2010, we reported the first such catalyst, complex 2. This complex is substantially faster than 1 and stable under homogeneous conditions. Recently, we have extended our efforts and reported a V2-analog of the complex 2, i.e. [Co4(H2O)2(α-VW9O34)2]10- (3), which shows an even greater stability and reactivity. We succeeded in: (a) immobilizing catalysts 1 and 2 on the surface of various electrodes, and (b) elucidating the mechanism of O2 formation and release from complex 1, as well as the Mn4O4L6 “cubane” cluster. We have shown that the direct O-O bond formation is the most likely pathway for O2 formation during water oxidation catalyzed by 1. II. Oxo transfer catalysts that contain two proximal and synergistically interacting redox active metal

  7. Removal of Disinfection By-Products from Contaminated Water Using a Synthetic Goethite Catalyst via Catalytic Ozonation and a Biofiltration System

    Directory of Open Access Journals (Sweden)

    Yu-Hsiang Wang

    2014-09-01

    Full Text Available The effects of synthetic goethite (α-FeOOH used as the catalyst in catalytic ozonation for the degradation of disinfection by-product (DBP precursors are investigated. A biofiltration column applied following the catalytic ozonation process is used to evaluate the efficiency of removing DBP precursors via biotreatment. Ozone can rapidly react with aromatic compounds and oxidize organic compounds, resulting in a decrease in the fluorescence intensity of dissolved organic matter (DOM. In addition, catalytic ozonation can break down large organic molecules, which causes a blue shift in the emission-excitation matrix spectra. Water treated with catalytic ozonation is composed of low-molecular structures, including soluble microbial products (SMPs and other aromatic proteins (APs. The DOM in SMPs and APs is removed by subsequent biofiltration. Catalytic ozonation has a higher removal efficiency for dissolved organic carbon and higher ultraviolet absorbance at 254 nm compared to those of ozonation without a catalyst. The use of catalytic ozonation and subsequent biofiltration leads to a lower DBP formation potential during chlorination compared to that obtained using ozonation and catalytic ozonation alone. Regarding DBP species during chlorination, the bromine incorporation factor (BIF of trihalomethanes and haloacetic acids increases with increasing catalyst dosage in catalytic ozonation. Moreover, the highest BIF is obtained for catalytic ozonation and subsequent biofiltration.

  8. Preparation of Molecular Sieve Catalyst and Application in the Catalytic Oxidation Treatment of Waste Water

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Citric acid is an important additive in foods, cosmetics, medicine and so on, but it discharges about 10 ton of factory effluent when 1 ton of citric acid is produced. The COD of the factory effluent is near 20000 mg/L. The treatment of citric acid factory effluent is a serious problem in environmental chemistry. It is found that molecular sieve support metal complexes have high catalytic activity in aerobic oxidation of alkene [1,2]. In this paper, a kind of molecular sieve catalyst was prepared. The catalyst was used for the treatment of citric acid factory effluent by method of catalytic oxygen oxidation.

  9. FREQUENCY CATASTROPHE AND CO-EXISTING ATTRACTORS IN A CELL Ca2+ NONLINEAR OSCILLATION MODEL WITH TIME DELAY*

    Institute of Scientific and Technical Information of China (English)

    应阳君; 黄祖洽

    2001-01-01

    Frequency catastrophe is found in a cell Ca2+ nonlinear oscillation model with time delay. The relation of the frequency transition to the time delay is studied by numerical simulations and theoretical analysis. There is a range of parameters in which two kinds of attractors with great frequency differences co-exist in the system. Along with parameter changes, a critical phenomenon occurs and the oscillation frequency changes greatly. This mechanism helps us to deepen the understanding of the complex dynamics of delay systems, and might be of some meaning in cell signalling.

  10. Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media

    Directory of Open Access Journals (Sweden)

    Mahfud Mahfud

    2011-02-01

    Full Text Available This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst

  11. A Broad Spectrum Catalytic System for Removal of Toxic Organics from Water by Deep Oxidation - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ayusman

    2000-12-01

    A most pressing need for the DOE environmental management program is the removal of toxic organic compounds present in groundwater and soil at specific DOE sites. While several remediation procedures have been proposed, they suffer from one or more drawbacks. The objective of the present research was to develop new catalytic procedures for the removal of toxic organic compounds from the environment through their deep oxidation to harmless products. In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of toxic organic compounds by dioxygen at 80-90 C in the presence of carbon monoxide or dihydrogen. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, nitro and halo organics, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 hour period. For substrates susceptible to hydrogenation, the conversions were generally high with dihydrogen than with carbon monoxide. It is clear from the results obtained that we have discovered an exceptionally versatile catalytic system for the deep oxidation of toxic organic compounds in water. This system possesses several attractive features not found simultaneously in other reported systems. These are (a) the ability to directly utilize dioxygen as the oxidant, (b) the ability to carry out the deep oxidation of a particularly wide range of functional organics, and (c) the ease of recovery of the catalyst by simple filtration.

  12. Preparation of Molecular Sieve Catalyst and Application in the Catalytic Oxidation Treatment of Waste Water

    Institute of Scientific and Technical Information of China (English)

    WANG; RongMin

    2001-01-01

    Citric acid is an important additive in foods, cosmetics, medicine and so on, but it discharges about 10 ton of factory effluent when 1 ton of citric acid is produced. The COD of the factory effluent is near 20000 mg/L. The treatment of citric acid factory effluent is a serious problem in environmental chemistry.  It is found that molecular sieve support metal complexes have high catalytic activity in aerobic oxidation of alkene [1,2]. In this paper, a kind of molecular sieve catalyst was prepared. The catalyst was used for the treatment of citric acid factory effluent by method of catalytic oxygen oxidation.  ……

  13. Elucidating molecular iridium water oxidation catalysts using metal-organic frameworks: a comprehensive structural, catalytic, spectroscopic, and kinetic study.

    Science.gov (United States)

    Wang, Cheng; Wang, Jin-Liang; Lin, Wenbin

    2012-12-01

    As a new class of porous, crystalline, molecular materials, metal-organic frameworks (MOFs) have shown great promise as recyclable and reusable single-site solid catalysts. Periodic order and site isolation of the catalytic struts in MOFs facilitate the studies of their activities and reaction mechanisms. Herein we report the construction of two highly stable MOFs (1 and 2) using elongated dicarboxylate bridging ligands derived from Cp*Ir(L)Cl complexes (L = dibenzoate-substituted 2,2'-bipyridine, bpy-dc, or dibenzoate-substituted 2-phenylpyridine, ppy-dc) and Zr(6)O(4)(OH)(4)(carboxylate)(12) cuboctahedral secondary building units (SBUs) and the elucidation of water oxidation pathways of the Cp*Ir(L)Cl catalysts using these MOFs. We carried out detailed kinetic studies of Ce(4+)-driven water oxidation reactions (WORs) catalyzed by the MOFs using UV-vis spectroscopy, phosphorescent oxygen detection, and gas chromatographic analysis. These results confirmed not only water oxidation activity of the MOFs but also indicated oxidative degradation of the Cp* rings during the WOR. The (bpy-dc)Ir(H(2)O)(2)XCl (X is likely a formate or acetate group) complex resulted from the oxidative degradation process was identified as a competent catalyst responsible for the water oxidation activity of 1. Further characterization of the MOFs recovered from WORs using X-ray photoelectron, diffuse-reflectance UV-vis absorption, luminescence, and infrared spectroscopies supported the identity of (bpy-dc)Ir(H(2)O)(2)XCl as an active water oxidation catalyst. Kinetics of MOF-catalyzed WORs were monitored by Ce(4+) consumptions and fitted with a reaction-diffusion model, revealing an intricate relationship between reaction and diffusion rates. Our work underscores the opportunity in using MOFs as well-defined single-site solid catalytic systems to reveal mechanistic details that are difficult to obtain for their homogeneous counterparts. PMID:23136923

  14. Preparation and Catalytic Application of Novel Water Tolerant Solid Acid Catalysts of Zirconium Sulfate/HZSM-5

    Institute of Scientific and Technical Information of China (English)

    JIANG Ya-jie; JUAN Joon Ching; MENG Xiu-juan; CAO Wei-liang; YARMO Mohd Ambar; ZHANG Jing-chang

    2007-01-01

    Esterification of acrylic acid(AA) to produce AA esters has widespread application in the chemical industry. A series of water tolerant solid acid catalysts was prepared, and characterized by XRD, nitrogen adsorption, TGA-DTA, XPS, and ammonia adsorption FTIR. The effects of Si/Al ratio, zirconium sulfate(ZS) loading on HZSM-5 and calcination temperature on the esterification were investigated. When 20%(mass fraction) ZS is loaded on HZSM-5, the conversion of AA reaches 100%. XRD analysis indicates that ZS is highly dispersed on HZSM-5 because no crystalline structure assigned to ZS is found. Catalytic activity and hydrophobicity of ZS supported on HZSM-5 are higher compared with those of parent ZS or HZSM-5. Results show that this kind of novel catalysts is an efficient water tolerant solid acid catalyst for esterification reactions.

  15. Transperitoneal repair of a juxtarenal abdominal aortic aneurysm and co-existent horseshoe kidney with division of the renal isthmus.

    Science.gov (United States)

    Hajibandeh, Shahin; Hajibandeh, Shahab; Johnpulle, Michelle; Perricone, Vittorio

    2015-01-01

    The co-existence of abdominal aortic aneurysm (AAA) and horseshoe kidney (HSK) is rare. We report a 67-year-old man with an expanding juxtarenal AAA associated with a HSK. The aneurysm had a severely angulated neck and contained a significant amount of mural thrombus. The isthmus of HSK closely lied over the aneurysm, making its exposure extremely difficult. The aneurysm was successfully repaired using transperitoneal approach with division of the renal isthmus and without any need for the renal artery reconstruction. Despite the potential complications, particularly renal insufficiency, associated with division of the renal isthmus and suprarenal cross-clamping of the abdominal aorta, in our case, post-operative period was uneventful and the patient's recovery was satisfactory. PMID:26511935

  16. Bayesian risk maps for Schistosoma mansoni and hookworm mono-infections in a setting where both parasites co-exist

    Directory of Open Access Journals (Sweden)

    Giovanna Raso

    2007-11-01

    Full Text Available There is growing interest in the use of Bayesian geostatistical models for predicting the spatial distribution of parasitic infections, including hookworm, Schistosoma mansoni and co-infections with both parasites. The aim of this study was to predict the spatial distribution of mono-infections with either hookworm or S. mansoni in a setting where both parasites co-exist. School-based cross-sectional parasitological and questionnaire surveys were carried out in 57 rural schools in the Man region, western Côte d’Ivoire. A single stool specimen was obtained from each schoolchild attending grades 3-5. Stool specimens were processed by the Kato-Katz technique and an ether concentration method and examined for the presence of hookworm and S. mansoni eggs. The combined results from the two diagnostic approaches were considered for the infection status of each child. Demographic data (i.e. age and sex were obtained from readily available school registries. Each child’s socio-economic status was estimated, using the questionnaire data following a household-based asset approach. Environmental data were extracted from satellite imagery. The different data sources were incorporated into a geographical information system. Finally, a Bayesian spatial multinomial regression model was constructed and the spatial patterns of S. mansoni and hookworm mono-infections were investigated using Bayesian kriging. Our approach facilitated the production of smooth risk maps for hookworm and S. mansoni mono-infections that can be utilized for targeting control interventions. We argue that in settings where S. mansoni and hookworm co-exist and control efforts are under way, there is a need for both mono- and co-infection risk maps to enhance the cost-effectiveness of control programmes.

  17. An insight to conserved water molecular dynamics of catalytic and structural Zn(+2) ions in matrix metalloproteinase 13 of human.

    Science.gov (United States)

    Chakrabarti, Bornali; Bairagya, Hridoy R; Mallik, Payel; Mukhopadhyay, Bishnu P; Bera, Asim K

    2011-02-01

    Matrix Metalloproteinase (MMP)--13 or Collagenase--3 plays a significant role in the formation and remodeling of bone, tumor invasion and causes osteoarthritis. Water molecular dynamic studies of the five (1XUC, 1XUD, 1XUR, 456C, 830C) PDB and solvated structures of MMP-13 in human have been carried out upto 5 ns on assigning the differential charges (+2, +1, +0.5 e) to both the Zinc ions. The MM and MD-studies have revealed the coordination of three water molecules (W(H), W(I) and W(S)) to Zn(c) and one water to Zn(s). The transition of geometry around the Znc from tetrahedral to octahedral via trigonal bipyramidal, and for Zn(s) from tetrahedral to trigonal bipyramidal are seem interesting. Recognition of two zinc ions through water molecular bridging (Zn(c) - W(H) (W(1))...W(2)....W(3)....H(187) Zn(s)) and the stabilization of variable coordination geometries around metal ions may indicate the possible involvement of Zn(c) ...Zn(s) coupled mechanism in the catalytic process. So the hydrophilic topology and stereochemistry of water mediated coupling between Zn-ions may provide some plausible hope towards the design of some bidentate/polydentate bridging ligands or inhibitors for MMP-13.

  18. On the study of catalytic membrane reactor for water detritiation: Membrane characterization

    Energy Technology Data Exchange (ETDEWEB)

    Mascarade, Jérémy, E-mail: jeremy.mascarade@cea.fr [CEA, DEN, DTN/STPA/LIPC Cadarache, F-13108 Saint Paul-lez-Durance (France); Liger, Karine; Troulay, Michèle [CEA, DEN, DTN/STPA/LIPC Cadarache, F-13108 Saint Paul-lez-Durance (France); Joulia, Xavier; Meyer, Xuan-Mi [CNRS, Laboratoire de Génie Chimique, F-31030 Toulouse (France); Perrais, Christophe [CEA, DEN, DTN/STPA/LIPC Cadarache, F-13108 Saint Paul-lez-Durance (France); Tosti, Silvano [ENEA, UTFUS, C.R. ENEA Frascati, Via E. Fermi 45, 00044 Frascati (RM) (Italy)

    2013-10-15

    Highlights: ► Catalytic palladium based membrane reactor is studied for ITER tritium waste management. ► Concentration polarization effect was highlighted by two-dimensional mass transfer model. ► Mass transfer resistance due to concentration polarization is reduced by the increase of fluid velocity. ► Concentration polarization phenomenon is enhanced by the decrease of non-permeable species content in the feed stream. -- Abstract: Tritium waste recycling is a real economic and ecological issue. Generally under the non-valuable Q{sub 2}O form (Q = H, D or T), waste can be converted into fuel Q{sub 2} for a fusion machine (e.g. JET, ITER) by isotope exchange reaction Q{sub 2}O + H{sub 2} = H{sub 2}O + Q{sub 2}. Such a reaction is carried out over Ni-based catalyst bed packed in a thin wall hydrogen permselective membrane tube. This catalytic membrane reactor can achieve higher conversion ratios than conventional fixed bed reactors by selective removal of reaction product Q{sub 2} by the membrane according to Le Chatelier's Law. This paper presents some preliminary permeation tests performed on a catalytic membrane reactor. Permeabilities of pure hydrogen and deuterium as well as those of binary mixtures of hydrogen, deuterium and nitrogen have been estimated by measuring permeation fluxes at temperatures ranging from 573 to 673 K, and pressure differences up to 1.5 bar. Pure component global fluxes were linked to permeation coefficient by means of Sieverts’ law. The thin membrane (150 μm), made of Pd–Ag alloy (23 wt.%{sub Ag}), showed good permeability and infinite selectivity toward protium and deuterium. Lower permeability values were obtained with mixtures containing non permeable gases highlighting the existence of gas phase resistance. The sensitivity of this concentration polarization phenomenon to the composition and the flow rate of the inlet was evaluated and fitted by a two-dimensional model.

  19. Study on Influence to Waste Water Treatment Plant’s Sludge by Low-carbon Catalytic Combustion Furnace of Natural Gas

    Directory of Open Access Journals (Sweden)

    Ren TianQi

    2016-01-01

    Full Text Available There are two parts in this experiment. One of is about the concentration of Variation of exhaust gas while heating sludge of waste water treatment plant. The other one is about introduce the problems of the traditional incineration processes of sludge of waste water treatment as compared between the sludge heated by natural gas catalytic combustion furnace and the tradition’s. We can see that natural gas low-carbon catalytic combustion furnace realize the near-zero emission of contaminates.

  20. The perception of parents and teachers of the influence of yoga on the concentration and co-existing behaviour of learners with attention deficit hyperactivity disorder (ADHD)

    OpenAIRE

    Beart, K; Lessing, Ansie C

    2013-01-01

    This pilot study explores the perception of parents and teachers of the influence of yoga on the concentration and some co-existing behaviour of learners diagnosed with attention deficit hyperactivity disorder (ADHD). The researchers attended to impaired concentration as typical ADHD behaviour and further looked at co-existing phenomena such as aggression, anxiety, and a low self-esteem which the learners may manifest. Semi-structured interviews with parents, teachers and the l...

  1. Effects of hydrophobic carrier and packing on the mass transfer capabilities in hydrogen-water liquid phase catalytic exchange bed

    International Nuclear Information System (INIS)

    Hydrogen-water liquid phase catalytic exchange bed was packed with 'sandwich' layers of the catalyst and the packing, and the effects of catalyst carrier, inert packing and their filled ratio on the overall mass transfer coefficient (Kya) were investigated experimentally. The results show that C-PTFE is suitable for hydrophobic catalyst. Kya of the bed with catalyst-stainless steel mini-spiral packing is better than that with stainless steel θ-packing, and the active Al2O3 is not suitable for the exchange bed. Moreover, if the stainless steel mini-spiral packing is etched in aqua regia, the operating flexibility and overall mass transfer capability of exchange bed are improved notably. The preferable packing ratio (catalyst/packing) is 1:4. (authors)

  2. Detritiation From Heavy Water by H2-H2O Liquid Phase Catalytic Exchange%氢-水液相催化交换法脱氚

    Institute of Scientific and Technical Information of China (English)

    李俊华

    2001-01-01

    对疏水催化剂的设计与制备方法及氢-水液相交换反应过程进行了讨论,并概要评述了以常温氢-水催化交换法进行重水脱氚的液相催化交换(LPCE)及其联合电解的催化交换(CECE)工艺流程。%The design and preparation of the hydrophobic catalyst used forthe hydrogen-water phase catalytic exchange reaction is discussed in the paper.Two kinds of the processes for the detritiation from the heavy water,liquid phase catalytic exchange(LPCE) and combined electrolysis catalytic exchange(CECE)are reviewed briefly.

  3. Water/oil microemulsion for the preparation of robust La-hexaaluminates for methane catalytic combustion.

    Science.gov (United States)

    Jiang, Zheng; Hao, Zhengping; Su, Jixi; Xiao, Tiancun; Edwards, Peter P

    2009-06-14

    Robust and highly effective Fe-substituted and non-substituted La-Hexaaluminate methane combustion catalysts have been prepared via coprecipitation in "water-pools" of Water/Oil microemulsions with dual nonionic surfactants, followed by ethanol supercritical drying and post-annealing. PMID:19587921

  4. On the Catalytic Effect of Water in the Intramolecular Diels–Alder Reaction of Quinone Systems: A Theoretical Study

    Directory of Open Access Journals (Sweden)

    Jorge Soto-Delgado

    2012-11-01

    Full Text Available The mechanism of the intramolecular Diels–Alder (IMDA reaction of benzoquinone 1, in the absence and in the presence of three water molecules, 1w, has been studied by means of density functional theory (DFT methods, using the M05-2X and B3LYP functionals for exploration of the potential energy surface (PES. The energy and geometrical results obtained are complemented with a population analysis using the NBO method, and an analysis based on the global, local and group electrophilicity and nucleophilicity indices. Both implicit and explicit solvation emphasize the increase of the polarity of the reaction and the reduction of activation free energies associated with the transition states (TSs of this IMDA process. These results are reinforced by the analysis of the reactivity indices derived from the conceptual DFT, which show that the increase of the electrophilicity of the quinone framework by the hydrogen-bond formation correctly explains the high polar character of this intramolecular process. Large polarization at the TSs promoted by hydrogen-bonds and implicit solvation by water together with a high electrophilicity-nucleophilicity difference consistently explains the catalytic effects of water molecules.

  5. Co-existence of Echinococcus granulosus infection and cancer metastasis in the liver correlates with reduced Th1 immune responses.

    Science.gov (United States)

    Turhan, N; Esendagli, G; Ozkayar, O; Tunali, G; Sokmensuer, C; Abbasoglu, O

    2015-01-01

    A possible relationship between cancer and Echinococcus granulosus infection has been postulated. As T cells are critical players in immune responses against both infections and malignancies, in an experimental model of secondary echinococcosis and breast cancer, this study aims to observe the progression of cancer and to determine the characters of T-cell responses. 4T1 breast tumour cells were subcutaneously injected into mammary region, whereas protoscoleces were intraperitoneally inoculated into the mice. Hydatid cysts, tumours and metastases were determined with macroscopic and histopathological evaluation. T cells found in spleen, liver and tumour were characterised by flow cytometric analysis of CD3, CD4, CD8, CD25, CCR5, CCR3, IL-4 and IFN-γ. In the mice inoculated both with protoscoleces and with breast tumour cells, increased frequency of cancer metastasis was observed in the liver. The amount of CD4(+) T cells was increased in the liver and in the spleen of mice infected with E. granulosus. However, co-existence of echinococcosis and metastatic lesions in the liver was associated with significant reduction in the IFN-γ(+) and CCR5(+) Th1 cells and increase in the CD25(+) T cells. Our results may indicate an immunological link between cystic echinococcosis and cancer that allows tumour metastasis to flourish in the liver.

  6. Sjögren syndrome and neuromyelitis optica spectrum disorder co-exist in a common autoimmune milieu

    Directory of Open Access Journals (Sweden)

    Diogo C. Carvalho

    2014-06-01

    Full Text Available The relationship between Sjögren’s syndrome (SS and neuromyelitis optica spectrum disorder (NMOSD is not completely understood. We report two patients with both conditions and review 47 other previously reported cases meeting currently accepted diagnostic criteria, from 17 articles extracted from PubMed. Out of 44 patients whose gender was informed, 42 were females. Mean age at onset of neurological manifestation was 36.2 years (10-74. Serum anti-AQP4-IgG was positive in 32 patients, borderline in 1, and negative in 4. Our Case 1 was seronegative for AQP4-IgG and had no non-organ-specific autoantibodies other than anti-SSB antibodies. Our Case 2 had serum anti-AQP4, anti-SSA/SSB, anti-thyreoglobulin and anti-acethylcholine-receptor antibodies, as well as clinical hypothyreoidism, but no evidence of myasthenia gravis. Our Cases and others, as previously reported in literature, with similar heterogeneous autoimmune response to aquaporin-4, suggest that SS and NMO co-exist in a common autoimmune milieu which is not dependent on aquaporin-4 autoimmunity.

  7. Heart Failure with Multi-organ Thrombosis: A Case of Antiphospholipid Syndrome Co-existing with Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Xueqi Li and Shipeng Wei

    2012-09-01

    Full Text Available Antiphospholipid Syndrome (APS is an autoimmune disease featured by venous or arterial thrombosis, fetal losses and thrombocytopenia in the presence of antiphospholipid antibodies. Here we reported one case of antiphospholipid syndrome together with dilated cardiomyopathy. A 46-year-old female patient complaining short of breath was found enlargement of atrial and ventricular compartments. The ecletrocardiogram and blood test revealed anteroseptal myocardial infarction, while no pulmonary thrombosis was present and therefore diagnosis of dilated cardiomyopathy was made. There were also thrombi formed in the cardial chambers and deep venous. During hospitalization, there was an onset of ischemic brain stroke and head MRI showed newly developed small infarctions. An elevation of anticardiolipin immunoglobulin A (ACAIGA was detected from the blood sample. The patient was discharged after being treated with anticoagulant, corticosteroid and other medicines for improving heart function. In our case, APS is the basic cause leading to multi-organ thrombosis and heart failure is mainly due to dilated cardiomyopathy, thus independent of APS. So this is the first time that cardiomyopathy co-existing with APS was reported.

  8. Tryptophanase from Escherichia coli: catalytic and spectral properties in water-organic solvents.

    Science.gov (United States)

    Faleev, N G; Dementieva, I S; Zakomirdina, L N; Gogoleva, O I; Belikov, V M

    1994-08-01

    In water-methanol and water-dimethylformamide (DMF) (1:1 v/v) solutions tryptophanase from E.coli retains its abilities to form a quinonoid complex with quasisubstrates and to catalyze the decomposition of S-o-nitrophenyl-L-cysteine (SOPC). Both the KM and Vmax values decrease in water-organic media. The affinities of tryptophanase for L-alanine, L-tryptophan, oxindolyl-L-alanine and indole in aqueous methanol are decreased, the effect being stronger for the more hydrophobic substances. In a water solution tryptophanase catalizes the reaction of SOPC with indole to form L-tryptophan while in water-organic solvents only decomposition of SOPC is observed.

  9. The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2014-01-01

    The presence of water often gives rise to oxygen adsorption on catalyst surfaces through decomposition of water and the adsorbed oxygen or hydroxide species often occupy important surfaces sites, resulting in a decrease or a total hindrance of other chemical reactions taking place at that site....... In this study, we present theoretical investigations of the influence of oxygen adsorption and reduction on pure and nitrogen covered molybdenum nanocluster electro catalysts for electrochemical reduction of N2 to NH3 with the purpose of understanding oxygen and water poisoning of the catalyst. Density...

  10. Identification of intrinsic catalytic activity for electrochemical reduction of water molecules to generate hydrogen

    KAUST Repository

    Shinagawa, Tatsuya

    2015-01-01

    Insufficient hydronium ion activities at near-neutral pH and under unbuffered conditions induce diffusion-limited currents for hydrogen evolution, followed by a reaction with water molecules to generate hydrogen at elevated potentials. The observed constant current behaviors at near neutral pH reflect the intrinsic electrocatalytic reactivity of the metal electrodes for water reduction. This journal is © the Owner Societies.

  11. A new class of photo-catalytic materials and a novel principle for efficient water splitting under infrared and visible light - MgB2 as unexpected example

    CERN Document Server

    Kravets, V G

    2015-01-01

    Water splitting is unanimously recognized as environment friendly, potentially low cost and renewable energy solution based on the future hydrogen economy. Especially appealing is photo-catalytic water splitting whereby a suitably chosen catalyst dramatically improves efficiency of the hydrogen production driven by direct sunlight and allows it to happen even at zero driving potential. Here, we suggest a new class of stable photo-catalysts and the corresponding principle for catalytic water splitting in which infrared and visible light play the main role in producing the photocurrent and hydrogen. The new class of catalysts based on ionic binary metals with layered graphite-like structures which effectively absorb visible and infrared light facilitating the reaction of water splitting, suppress the inverse reaction of ion recombination by separating ions due to internal electric fields existing near alternating layers, provide the sites for ion trapping of both polarities, and finally deliver the electrons an...

  12. Experimental studies on catalytic hydrogen recombiners for light water reactors; Experimentelle Untersuchungen zu katalytischen Wasserstoffkombinatoren fuer Leichtwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Drinovac, P.

    2006-06-19

    In the course of core melt accidents in nuclear power plants a large amount of hydrogen can be produced and form an explosive or even detonative gas mixture with aerial oxygen in the reactor building. In the containment atmosphere of pressurized water reactors hydrogen combines a phlogistically with the oxygen present to form water vapor even at room temperature. In the past, experimental work conducted at various facilities has contributed little or nothing to an understanding of the operating principles of catalytic recombiners. Hence, the purpose of the present study was to conduct detailed investigations on a section of a recombiner essentially in order to deepen the understanding of reaction kinetics and heat transport processes. The results of the experiments presented in this dissertation form a large data base of measurements which provides an insight into the processes taking place in recombiners. The reaction-kinetic interpretation of the measured data confirms and deepens the diffusion theory - proposed in an earlier study. Thus it is now possible to validate detailed numeric models representing the processes in recombiners. Consequently the present study serves to broaden and corroborate competence in this significant area of reactor technology. In addition, the empirical knowledge thus gained may be used for a critical reassessment of previous numeric model calculations. (orig.)

  13. STUDY ON SYNTHESIS OF PVC SERIES OF MACROPOROUS SULFORIC RESINS AND THEIR APPLICATIONS IN CATALYTIC ESTERIFICATION AND WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    LIYanfeng; FULiandi; 等

    1999-01-01

    The PVC serves of macroporous sulfonic cation-exchange resins were prepared by the sulfonation of a macroporous PVC bead with concentrated sulfonic acid or chlorosulfonic acid.the resulting sulfonic resin was employed in the investigation of catalytic esterification and solftening of water,The results show that the yields of esters reach 60.0-84.4% according as different fatty acids and alcohols,the refractive indexes of esters obtained resemble those reported in the references basically,meanwhile,345L softened water which holds ≤0.06mmol/L hardness would be prepared by 1 L wet sulfonic resin reusing for 4 times.The resulting sulfonic resins would have 1.6-2.0or 2.5-3.0mmol/g exchange capacity by using concentrated sulfonic acid or chlorosulfonic acid as sulfonating agent,respectively,The sulfonic resin has a macroporous structure taking the morphology with agglomerates of minutely spherical gel particles as characteristic.

  14. Effect of co-existing kaolinite and goethite on the aggregation of graphene oxide in the aquatic environment.

    Science.gov (United States)

    Huang, Guanxing; Guo, Huiyuan; Zhao, Jian; Liu, Yonghong; Xing, Baoshan

    2016-10-01

    Broad applications of graphene oxide (GO) will result in the release of GO into aquatic environments, where clay minerals and metal (hydr)oxides are commonly present. Thereby the interactions between GO and a binary system containing clay minerals and metal (hydr)oxides can occur. We investigated the aggregation of GO with kaolinite and kaolinite-goethite associations (KGAs) in aquatic systems under different pHs, ionic strengths, and GO concentrations. GO suspension was unstable at low pHs, and the aggregation of GO occurred in the presence of KGA-4% and KGA-10% until pH 5 and 6, respectively. Kaolinite decreased the critical coagulation concentration (CCC) of GO at pH 5.5 from around 50 to 20 mM NaCl due to the reduced energy barrier. Heteroaggregation of GO with KGAs was extremely sensitive to ionic strength at pH 5.5, and the CCC of GO in the presence of KGA-10% increased from less than 1 mM NaCl to 5 mM NaCl with the increase of pH from 5.5 to 9. The heteroaggregation extent of GO with KGAs was enhanced firstly, then reduced with the increase of GO concentrations at pH 5.0, which is likely because KGA plates were more efficiently wrapped by large-size GO sheets with increasing GO concentrations. These findings are useful for understanding and predicting the fate of GO in the relatively complicated aquatic and soil environments where binary minerals co-exist. PMID:27379727

  15. Staphylococcus aureus SrrAB Affects Susceptibility to Hydrogen Peroxide and Co-Existence with Streptococcus sanguinis

    Science.gov (United States)

    Oogai, Yuichi; Kawada-Matsuo, Miki; Komatsuzawa, Hitoshi

    2016-01-01

    Staphylococcus aureus is a pathogen and a commensal bacterial species that is found in humans. Bacterial two-component systems (TCSs) sense and respond to environmental stresses, which include antimicrobial agents produced by other bacteria. In this study, we analyzed the relation between the TCS SrrAB and susceptibility to the hydrogen peroxide (H2O2) that is produced by Streptococcus sanguinis, which is a commensal oral streptococcus. An srrA-inactivated S. aureus mutant demonstrated low susceptibility to the H2O2 produced by S. sanguinis. We investigated the expression of anti-oxidant factors in the mutant. The expression of katA in the mutant was significantly higher than in the wild-type (WT) in the presence or absence of 0.4 mM H2O2. The expression of dps in the mutant was significantly increased compared with the WT in the presence of H2O2 but not in the absence of H2O2. A katA or a dps-inactivated mutant had high susceptibility to H2O2 compared with WT. In addition, we found that the nitric oxide detoxification protein (flavohemoglobin: Hmp), which is regulated by SrrAB, was related to H2O2 susceptibility. The hmp-inactivated mutant had slightly lower susceptibility to the H2O2 produced by S. sanguinis than did WT. When a srrA-inactivated mutant or the WT were co-cultured with S. sanguinis, the population percentage of the mutant was significantly higher than the WT. In conclusion, SrrAB regulates katA, dps and hmp expression and affects H2O2 susceptibility. Our findings suggest that SrrAB is related in vivo to the co-existence of S. aureus with S. sanguinis. PMID:27441894

  16. Catalytic Conversion of Dihydroxyacetone to Lactic Acid Using Metal Salts in Water

    NARCIS (Netherlands)

    Rasrendra, Carolus B.; Fachri, Boy A.; Makertihartha, I. Gusti B. N.; Adisasmito, Sanggono; Heeres, Hero J.

    2011-01-01

    We herein present a study on the application of homogeneous catalysts in the form of metal salts on the conversion of trioses, such as dihydroxyacetone (DHA), and glyceraldehyde (GLY) to lactic acid (LA) in water. A wide range of metal salts (26 in total) were examined. Al(III) salts were identified

  17. First-principles quantum mechanical investigations: Catalytic reactions of furfural on Pd(111) and at the water/Pd(111) interface

    Science.gov (United States)

    Xue, Wenhua

    Bio-oils have drawn more and more attention from scientists as a promising new clean, cheap energy source. One of the most interesting relevant issues is the effect of catalysts on the catalytic reactions that are used for producing bio-oils. Furfural, as a very important intermediate during these reactions, has attracted significant studies. However, the effect of catalysts, including particularly the liquid/solid interface formed by a metal catalyst and liquid water, in the catalytic reactions involving furfural still remains elusive. In this research, we performed ab initio molecular dynamics simulations and first-principles density-functional theory calculations to investigate the atomic-scale mechanisms of catalytic hydrogenation of furfural on the palladium surface and at the liquid/state interface formed by the palladium surface and liquid water. We studied all the possible mechanisms that lead to formation of furfuryl alcohol (FOL), formation of tetrahydrofurfural (THFAL), and formation of tetrahydrofurfurfuryl alcohol (THFOL). We found that liquid water plays a significant role in the hydrogenation reactions. During the reaction in the presence of water and the palladium catalyst, in particular, water directly participates in the hydrogenation of the aldehyde group of furfural and facilitates the formation of FOL by reducing the activation energy. Our calculations show that water provides hydrogen for the hydrogenation of the aldehyde group, and at the same time, a pre-existing hydrogen atom, which is resulted from dissociation of molecular hydrogen (experimentally, molecular hydrogen is always supplied for hydrogenation) on the palladium surface, is bonded to water, making the water molecule intact in structure. In the absence of water, on the other hand, formation of FOL and THFAL on the palladium surface involves almost the same energy barriers, suggesting a comparable selectivity. Overall, as water reduces the activation energy for the formation of FOL

  18. Catalytic water dissociation by greigite Fe3S4 surfaces: density functional theory study

    OpenAIRE

    Roldan, A.; de Leeuw, N. H.

    2016-01-01

    The iron sulfide mineral greigite, Fe3S4, has shown promising capability as a hydrogenating catalyst, in particular in the reduction of carbon dioxide to produce small organic molecules under mild conditions. We employed density functional theory calculations to investigate the {001},{011} and {111} surfaces of this iron thiospinel material, as well as the production of hydrogen ad-atoms from the dissociation of water molecules on the surfaces. We systematically analysed the adsorption geomet...

  19. Gasificación catalítica de lodos de aguas residuales. // Catalytic gasification of residual waters muds.

    Directory of Open Access Journals (Sweden)

    L. M. García Rojas

    2005-05-01

    Full Text Available A partir de la necesidad de encontrar nuevas alternativas energéticas, se estudia en este trabajo la posibilidad de reducir agran escala la cantidad de alquitranes que acompaña al gas obtenido de la gasificación en lecho fluidizado de los lodos delas depuradoras de aguas residuales, este estudio conduce a una posible utilización de este gas en la generación deelectricidad, Para propiciar tal reducción se han empleado catalizadores secundarios reemplazando, en parte ocompletamente, la arena utilizada como agente fluidizante. Además la presencia de vapor de agua, que puede actuar comoreactante para el reformado de hidrocarburos, también puede ser beneficiosa a la hora de reducir la cantidad de alquitranesen el gas, por lo que, junto con la sustitución de la arena por un catalizador, se han realizado experimentos alimentandovapor de agua al reactor.Palabras claves: Gasificación, lecho fluidizado y lodos.____________________________________________________________________________Abstract.Starting from the necessity of finding new energy alternatives, it is presented in this paper the possibility to reduce in greatscale the quantity of tars that accompanies the gas obtained of the gasification in fluidized bed of muds in residual waters,this study leads to a possible use of this gas in the electricity generation, For propitiate such reduction a secondary catalystshas been used replacing, partly or completely, the sand used as fluidity agent. Also the presence of water steam that can actas reactant for the hydrocarbons reformed, it can also be beneficial when reducing the quantity of tars in the gas, for that,together with the substitution of sand for a catalyst, it have been carried out experiments feeding water steam to the reactor.Key words: Catalytic gasification, fluidity channel, muds.

  20. The effect of copper valence on catalytic combustion of styrene over the copper based catalysts in the absence and presence of water vapor☆

    Institute of Scientific and Technical Information of China (English)

    Hongyan Pan; Zhiyan He; Qian Lin; Fei Liu; Zhong Li

    2016-01-01

    Catalysts CuOx/γ-Al2O3-IH and CuOx/γ-Al2O3-IM were prepared, characterized, and tested for styrene combustion in the absence and presence of water vapor. The effect of copper valence of the catalysts on the catalytic activity for styrene combustion was discussed using the theory of hard soft acids and bases (HSAB). The results showed that the existence of water vapor in feed stream inhibited the catalytic activity for styrene combustion due to the competition adsorption of water molecule. HSAB theory confirmed that the local soft acidity of the catalyst CuOx/γ-Al2O3-IH was much stronger than that of the catalyst CuOx/γ-Al2O3-IM because of the higher content of soft acid Cu+on its surface, which increased the adsorption ability toward soft base of styrene and reduced the adsorption toward hard base of water vapor, and thus increased the catalytic activity for styrene combustion and weakened the negative influence of water vapor.

  1. Removal performance and mechanism of ibuprofen from water by catalytic ozonation using sludge-corncob activated carbon as catalyst.

    Science.gov (United States)

    Wang, Hongjuan; Zhang, Liqiu; Qi, Fei; Wang, Xue; Li, Lu; Feng, Li

    2014-09-01

    To discover the catalytic activity of sludge-corncob activated carbon in catalytic ozonation of Ibuprofen, the performance of sludge-corncob activated carbon and three selected commercial activated carbons as catalysts in catalytic ozonation was investigated. The observation indicates the degradation rate of Ibuprofen increases significantly in the presence of sludge-corncob activated carbon and the catalytic activity of sludge-corncob activated carbon is much higher than that of the other three commercial activated carbons. Ibuprofen's removal rate follows pseudo-first order kinetics model well. It is also found that the adsorption removal of Ibuprofen by sludge-corncob activated carbon is less than 30% after 40 min. And the removal efficiency of Ibuprofen in the hybrid ozone/sludge-corncob activated carbon system is higher than the sum of sludge-corncob activated carbon adsorption and ozonation alone, which is a supportive evidence for catalytic reaction. In addition, the results of radical scavenger experiments demonstrate that catalytic ozonation of Ibuprofen by sludge-corncob activated carbon follows a hydroxyl radical reaction pathway. During ozonation of Ibuprofen in the presence of activated carbon, ozone could be catalytically decomposed to form hydrogen peroxide, which can promote the formation of hydroxyl radical. The maximum amount of hydrogen peroxide occurs in the presence of sludge-corncob activated carbon, which can explain why sludge-corncob activated carbon has the best catalytic activity among four different activated carbons.

  2. Preparation and characterization of a biochar from pistachio hull biomass and its catalytic potential for ozonation of water recalcitrant contaminants.

    Science.gov (United States)

    Moussavi, Gholamreza; Khosravi, Rasoul

    2012-09-01

    This work introduces a biochar as novel catalyst prepared from the pistachio hull, and demonstrates its catalytic potential for degrading the reactive red 198 (RR198) dye in catalytic ozonation processes (COPs). The prepared pistachio hull biochar (PHB) was a macroporous, basic material with low specific surface area. PHB had the greatest catalytic potential at an optimal alkaline pH of 10. Significant catalytic potential was observed when PHB was added to the ozonation reactor; a 58.4% catalytic potential was obtained in the decolorization of RR198 in the COP with 0.2g of catalyst after a reaction time of 60 min. A 71% mineralization (TOC reduction) of the dye solution was observed in the COP after a reaction time of 60 min. Overall, it can be concluded from the experimental results that the PHB is a promising and affordable catalyst for use in COPs for treatment of resistant organic compounds.

  3. Micro-channel catalytic reactor integration in CAPER and research/development on highly tritiated water handling and processing

    International Nuclear Information System (INIS)

    The CAPER facility of the Tritium Laboratory Karlsruhe has demonstrated the technology for the tokamak exhaust processing. CAPER has been significantly upgraded to pursue research/development programs towards highly tritiated water (HTW) handling and processing. The preliminary tests using a metal oxide reactor producing HTW afterward de-tritiated with PERMCAT were successful. In a later stage, a micro-channel catalytic reactor was installed in view of long term research program on HTW. The integration of this new system in CAPER was carried out along with a careful safety analysis due to high risk associated with such experiments. First experiments using the μ-CCR were performed trouble free, and HTW up to 360 kCi/kg was produced at a rate of 0.5 g/h. Such HTW was collected into a platinum zeolite bed (2 g of HTW for 20 g of Pt-zeolite), and in-situ detritiation was performed via isotopic exchange with deuterium. These first experimental results with tritium confirmed the potential for the capture and exchange method to be used for HTW in ITER. (authors)

  4. 催化光度法测定水中的氟%Catalytic Spectrophotometric Determination of Fluoride in Water

    Institute of Scientific and Technical Information of China (English)

    李志英; 孙一飞

    2011-01-01

    Under neutral conditions, free fluorion ions can catalyze the discoloration reaction of acidic chrome blue K with H2O2. Based on this,a novel catalytic spectrophotometric method was proposed to determine trace F-. The results showed that the maximum absorption wavelength of the color solution was 522 nm, the linear range of the determination was 0. 4~11. 2μg/mL, and the detection limit was 9. 9×10-4 μg/mL. The method was used to determine fluoride in water with satisfactory results.%在中性溶液中,游离的F-对H2O2氧化酸性铬兰K褪色反应具有催化作用,基于此建立了测定微量F-的催化光度分析的新方法.结果表明,有色溶液的最大吸收波长为522 nm,测定的线性范围为0.4~11.2 μg/mL,检出限为9.9×10-4 μg/mL.该法用于水中微量F-的测定,结果令人满意.

  5. Bio-electro catalytic treatment of petroleum produced water: Influence of cathode potential upliftment.

    Science.gov (United States)

    Jain, Pratiksha; Srikanth, Sandipam; Kumar, Manoj; Sarma, Priyangshu M; Singh, M P; Lal, Banwari

    2016-11-01

    Treatment of petroleum produced water (PPW) was studied using bioelectrochemical system (BES) under uplifted cathode potential. The treatment efficiency in terms of COD and hydrocarbon removal was observed at 91.25% and 76.60% respectively, along with the reduction in TDS during BES operation under 400mV of cathode potential. There was also a reduction in concentration of sulfates, however, it was not significant at, since oxidative conditions are being maintained at anode. Improved oxidation of PPW at anode also resulted in good power output (-20.47mA) and also depicted improved fuel cell behaviour. The electrochemical analysis in terms of cyclic/linear sweep voltammetry also showed well correlation with the observed treatment efficiencies. The microbial dynamics of the BES after loading real field wastewater showed the dominance of species that are reported to be effective for petroleum crude oil degradation. PMID:27544915

  6. Solar Photo Catalytic Hydrogen Production from water using a dual bed photosystem

    Energy Technology Data Exchange (ETDEWEB)

    Florida Solar Energy Center

    2003-03-30

    A body of work was performed in which the feasibility of photocatalytically decomposing water into its constituent elements using a dual bed, or modular photosystem, under solar radiation was investigated. The system envisioned consists of two modules, each consisting of a shallow, flat, sealed container, in which microscopic photocatalytic particles are immobilized. The photocatalysts absorb light, generating free electrons and lattice vacancy holes, which are capable of performing reductive and oxidative chemistry, respectively. The photocatalysts would be chosen as to whether they specifically promote H{sub 2} or O{sub 2} evolution in their respective containers. An aqueous solution containing a redox mediator is pumped between the two chambers in order to transfer electron equivalents from one reaction to the other.

  7. Tandem Catalytic Depolymerization of Lignin by Water-Tolerant Lewis Acids and Rhodium Complexes.

    Science.gov (United States)

    Jastrzebski, Robin; Constant, Sandra; Lancefield, Christopher S; Westwood, Nicholas J; Weckhuysen, Bert M; Bruijnincx, Pieter C A

    2016-08-23

    Lignin is an attractive renewable feedstock for aromatic bulk and fine chemicals production, provided that suitable depolymerization procedures are developed. Here, we describe a tandem catalysis strategy for ether linkage cleavage within lignin, involving ether hydrolysis by water-tolerant Lewis acids followed by aldehyde decarbonylation by a Rh complex. In situ decarbonylation of the reactive aldehydes limits loss of monomers by recondensation, a major issue in acid-catalyzed lignin depolymerization. Rate of hydrolysis and decarbonylation were matched using lignin model compounds, allowing the method to be successfully applied to softwood, hardwood, and herbaceous dioxasolv lignins, as well as poplar sawdust, to give the anticipated decarbonylation products and, rather surprisingly, 4-(1-propenyl)phenols. Promisingly, product selectivity can be tuned by variation of the Lewis-acid strength and lignin source. PMID:27440544

  8. A non-acid-assisted and non-hydroxyl-radical-related catalytic ozonation with ceria supported copper oxide in efficient oxalate degradation in water

    KAUST Repository

    Zhang, Tao

    2012-06-01

    Oxalate is usually used as a refractory model compound that cannot be effectively removed by ozone and hydroxyl radical oxidation in water. In this study, we found that ceria supported CuO significantly improved oxalate degradation in reaction with ozone. The optimum CuO loading amount was 12%. The molar ratio of oxalate removed/ozone consumption reached 0.84. The catalytic ozonation was most effective in a neutral pH range (6.7-7.9) and became ineffective when the water solution was acidic or alkaline. Moreover, bicarbonate, a ubiquitous hydroxyl radical scavenger in natural waters, significantly improved the catalytic degradation of oxalate. Therefore, the degradation relies on neither hydroxyl radical oxidation nor acid assistance, two pathways usually proposed for catalytic ozonation. These special characters of the catalyst make it suitable to be potentially used for practical degradation of refractory hydrophilic organic matter and compounds in water and wastewater. With in situ characterization, the new surface Cu(II) formed from ozone oxidation of the trace Cu(I) of the catalyst was found to be an active site in coordination with oxalate forming multi-dentate surface complex. It is proposed that the complex can be further oxidized by molecular ozone and then decomposes through intra-molecular electron transfer. The ceria support enhanced the activity of the surface Cu(I)/Cu(II) in this process. © 2012 Elsevier B.V.

  9. How Does the Reductase Help To Regulate the Catalytic Cycle of Cytochrome P450 3A4 Using the Conserved Water Channel?

    OpenAIRE

    Fishelovitch, Dan; Shaik, Sason; Wolfson, Haim J.; Nussinov, Ruth

    2010-01-01

    Water molecules play a major role in the P450 catalytic cycle. Here, we locate the preferred water pathways and their gating mechanisms for the human cytochrome P450 3A4 (CYP3A4) and elucidate the role of the cytochrome P450 reductase (CPR) in turning on and activating these water channels. We perform explicit solvent molecular dynamic simulations of CYP3A4, unbound and bound to two substrates, and with and without the flavin mononucleotide (FMN)-binding domain of CPR. We observe in/out passa...

  10. Governing the co-existence of GM crops : ex-ante regulation and ex-post liability under uncertainty and irreversibility

    NARCIS (Netherlands)

    Beckmann, V.; Soregaroli, C.; Wesseler, J.H.H.

    2006-01-01

    The future institutional environment for the co-existence of genetically modified (GM) crops, conventional crops and organic crops in Europe combines measures of ex-ante regulation and ex-post liability rules. Against this background we ask the following two questions: How does ex-ante regulation an

  11. On the co-existence of chemically peculiar Bp stars, slowly pulsating B stars and constant B stars in the same part of the H-R diagram

    NARCIS (Netherlands)

    Briquet, M.; Hubrig, S.; Cat, P. de; Aerts, C.; North, P.; Schöller, M.

    2007-01-01

    Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of the H-R diagram. Methods: We carry out a comparative study

  12. Support effects and catalytic trends for water gas shift activity of transition metals

    DEFF Research Database (Denmark)

    Boisen, Astrid; Janssens, T.V.W.; Schumacher, Nana Maria Pii;

    2010-01-01

    CO and atomic oxygen on the metal; the latter is a good measure for the reactivity of the metal towards H2O. Generally, the activity of the catalysts with the Ce0.75Zr0.25O2 support is higher, compared to the corresponding MgAl2O4-supported catalysts. Exceptions are Cu and Au, which have a higher......Water gas shift activity measurements for 12 transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Re, Ir, Pt, Au) supported on inert MgAl2O4 and Ce0.75Zr0.25O2 are presented, to elucidate the influence of the active metal and the support. The activity is related to the adsorption energy of molecular...... activity on the MgAl2O4 support and are both characterized by weak CO adsorption. For the MgAl2O4-supported catalysts a volcano-type relation between the activity and the adsorption energy of atomic oxygen on the metal is obtained. The maximum activity is found for metals with a binding energy of oxygen...

  13. The catalytic role of tungsten electrode material in the plasmachemical activity of a pulsed corona discharge in water

    International Nuclear Information System (INIS)

    The effects of tungsten material used as a high-voltage needle electrode on the production of hydrogen peroxide and the degradation of dimethylsulfoxide (DMSO) caused by a pulsed corona discharge in water were investigated. A reactor of needle-plate electrode geometry was used. The erosion of the tungsten electrodes by the discharge was evaluated. The yields of H2O2 production and the decomposition of DMSO by the discharge, which were obtained using the tungsten electrodes, were compared with those determined for titanium electrodes. The electrode erosion increased significantly with an increase in the solution conductivity. A large fraction (50-70%) of the eroded tungsten electrode material was released into the solution in dissolved form as tungstate WO42- ions. A correlation between the amount of eroded tungsten material released into the solution and the chemical effects induced by the discharge was determined. Lower yields of H2O2 and a higher degradation of DMSO by the discharge were obtained using the tungsten electrodes than were determined using titanium electrodes. Tungstate ions were shown to play a dominant role in the decomposition of H2O2, which was produced by the discharge using a tungsten electrode. The higher degradation of DMSO that was determined for tungsten was attributed to the tungstate-catalyzed oxidation of DMSO by H2O2, in addition to the oxidation of DMSO by OH radicals. Such a mechanism was supported by the detection of degradation by-products of DMSO (methanesulfonate, sulfate and dimethyl sulfone). The catalytic role of tungstate ions in the plasmachemical activity of the discharge generated using a tungsten electrode was also demonstrated on a pH-dependent decomposition of H2O2 and DMSO.

  14. The catalytic role of tungsten electrode material in the plasmachemical activity of a pulsed corona discharge in water

    Energy Technology Data Exchange (ETDEWEB)

    Lukes, Petr; Clupek, Martin; Babicky, Vaclav [Department of Pulse Plasma Systems, Institute of Plasma Physics, Academy of Sciences of the Czech Republic, v.v.i. Za Slovankou 3, Praha 8, 182 00 (Czech Republic); Sisrova, Irena; Janda, Vaclav, E-mail: lukes@ipp.cas.cz [Department of Water Technology and Environmental Engineering, Faculty of Environmental Technology, Institute of Chemical Technology, Technicka 5, Prague 6, 166 28 (Czech Republic)

    2011-06-15

    The effects of tungsten material used as a high-voltage needle electrode on the production of hydrogen peroxide and the degradation of dimethylsulfoxide (DMSO) caused by a pulsed corona discharge in water were investigated. A reactor of needle-plate electrode geometry was used. The erosion of the tungsten electrodes by the discharge was evaluated. The yields of H{sub 2}O{sub 2} production and the decomposition of DMSO by the discharge, which were obtained using the tungsten electrodes, were compared with those determined for titanium electrodes. The electrode erosion increased significantly with an increase in the solution conductivity. A large fraction (50-70%) of the eroded tungsten electrode material was released into the solution in dissolved form as tungstate WO{sub 4}{sup 2-} ions. A correlation between the amount of eroded tungsten material released into the solution and the chemical effects induced by the discharge was determined. Lower yields of H{sub 2}O{sub 2} and a higher degradation of DMSO by the discharge were obtained using the tungsten electrodes than were determined using titanium electrodes. Tungstate ions were shown to play a dominant role in the decomposition of H{sub 2}O{sub 2}, which was produced by the discharge using a tungsten electrode. The higher degradation of DMSO that was determined for tungsten was attributed to the tungstate-catalyzed oxidation of DMSO by H{sub 2}O{sub 2}, in addition to the oxidation of DMSO by OH radicals. Such a mechanism was supported by the detection of degradation by-products of DMSO (methanesulfonate, sulfate and dimethyl sulfone). The catalytic role of tungstate ions in the plasmachemical activity of the discharge generated using a tungsten electrode was also demonstrated on a pH-dependent decomposition of H{sub 2}O{sub 2} and DMSO.

  15. Determination of Trace Vanadium(V)in Seawater and Fresh Water by the Catalytic Kinetic Spectrophotometric Method

    Institute of Scientific and Technical Information of China (English)

    JI Hongwei; SHA Yuanyuan; XIN Huizhen; LI Shuang

    2010-01-01

    A new kinetic spectrophotometric method has been developed for the determination of vanadium(V).The method is based on the catalytic effect of vanadium(V)on the oxidation of weak acid brilliant blue dye(RAWL)by KBrO3 using the citric acid as activation reagent.The obtained optimum conditions are:c(RAWL)= 1×10-4 molL-1,c(KBrO3)= 3×10-2 molL-1,c(citric acid)=9×10-3 molL-1,pH = 2.50,the reaction time being 7.0min and the temperature being 25.0℃.Under the optimum conditions,the proposed method allows the determination of vanadium(V)in the range of 0-70.0ng mL-1 and the detection limit is down to 0.407 ng mL-1.For standard vanadium(V)solution determination,the recovery efficiency is in the range of 98.5%-102% and the RSD ranges from 0.76%-1.25%.Moreover,it is demonstrated that most cations and anions do not interfere with the determination of vanadium(V)under the analytical condition.The new method was successfully applied in the determination of vanadium(V)in fresh water and seawater samples with satisfactory results.Vanadium(V)in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium(V)was mapped.Compared with other instrumental analytical methods,the proposed method shows good selectivity,sensitivity,simplicity,lower cost and rapidity.It can be employed on shipboard easily.

  16. Effect of Mg/Al atom ratio of support on catalytic performance of Co-Mo/MgO-Al2O3 catalyst for water gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    Yixin Lian; Huifang Wang; Quanxing Zheng; Weiping Fang; Yiquan Yang

    2009-01-01

    Co-Mo-based catalysts supported on mixed oxide supports MgO-Al2O3 with different Mg/Al atom ratios for water gas shift reaction were studied by means of TPR, Raman, XPS and ESR. It was found that the octahedral Mo species in oxidized Co-Mo/MgO(x)-Al2O3 catalyst and the contents of Mo5+, Mo4+, S2- and S2-2 species in the functioning catalysts increased with increasing the Mg/Al atom ratio of the support under the studied experimental conditions. This is favorable for the formation of the active Co-Mo-S phase of the catalysts. Catalytic performance testing results showed that the catalysts Co-Mo/MgO-Al2O3 with the Mg/Al atom ratio of the support in the range of 0.475-0.525 exhibited optimal catalytic activity for the reaction.

  17. Large scale analysis of co-existing post-translational modifications in histone tails reveals global fine structure of cross-talk

    DEFF Research Database (Denmark)

    Schwämmle, Veit; Aspalter, Claudia-Maria; Sidoli, Simone;

    2014-01-01

    sample-specific patterns for the co-frequency of histone post-translational modifications. We implemented a new method to identify positive and negative interplay between pairs of methylation and acetylation marks in proteins. Many of the detected features were conserved between different cell types......Mass spectrometry (MS) is a powerful analytical method for the identification and quantification of co-existing post-translational modifications in histone proteins. One of the most important challenges in current chromatin biology is to characterize the relationships between co-existing histone...... sites but negative cross-talk for distant ones, and for discrete methylation states at Lys-9, Lys-27, and Lys-36 of histone H3, suggesting a more differentiated functional role of methylation beyond the general expectation of enhanced activity at higher methylation states....

  18. Plant co-existence patterns and High-Arctic vegetation composition in three common plant communities in north-east Greenland

    Directory of Open Access Journals (Sweden)

    Oriol Grau

    2014-09-01

    Full Text Available Arctic regions are expected to experience substantial changes in climate in the coming decades. In order to predict potential changes of Arctic vegetation, it is important to understand the distinct role of life forms of plants and of individual species in relation to plant co-existence patterns. Our aim is to investigate if three common Arctic plant patch types dominated by contrasting life forms (by the dwarf shrubs Salix arctica or Dryas octopetala×intermedia or by mosses are related (a to the co-existence of vascular plants and species richness at patch scale and (b to the floristic composition in three distinct plant communities (Salix snowbed, Dryas heath and fell-field associated with contrasting abiotic regimes. The study was conducted at Zackenberg, in north-east Greenland. Dryas patches showed a clear negative effect on small-scale plant richness and co-existence in the fell-field. Salix and moss patches showed a similar pattern in all the plant communities, although the number of individuals growing in Salix patches was lower than in moss patches. Salix and mosses in the fell-fields hosted a high number of species in spite of the much less vegetated aspect of this harsh, upper zone. The floristic composition varied between plant communities, but it did not change substantially between patch types within each community. This study provides novel background knowledge of plant co-existence patterns at patch scale and of the structure of contrasting Arctic plant communities, which will help to better assess the potential effects of varying abiotic stress regimes on Arctic vegetation.

  19. Increased frequency of co-existing JAK2 exon-12 or MPL exon-10 mutations in patients with low JAK2(V617F) allelic burden.

    Science.gov (United States)

    Nussenzveig, Roberto H; Pham, Ha T; Perkins, Sherrie L; Prchal, Josef T; Agarwal, Archana M; Salama, Mohamed E

    2016-01-01

    The frequency of co-existing JAK2(V617F)/MPL and JAK2(V617F)/JAK2 exon-12 mutations has not been previously investigated in MPNs. Poor survival was reported in primary myelofibrosis with low JAK2(V617F) allelic burden. However, mutational status of JAK2 exon-12 or MPL were not reported in these patients. This study developed a cost-effective multiplex high resolution melt assay that screens for mutations in JAK2 gene exons-12 and -14 ((V617F)) and MPL gene exon-10. Co-existing mutations with JAK2(V617F) were detected in 2.9% (6/208; two JAK2 exon-12 and four MPL exon-10) patient specimens with known JAK2(V617F) (allelic-burden range: 0.1-96.8%). Co-existing mutations were detected in specimens with < 12% JAK2(V617F) allelic burden. Current WHO guidelines do not recommend further testing once JAK2(V617F) mutation is detected in MPNs. The findings, however, indicate that quantification of JAK2(V617F) allele burden may be clinically relevant in MPNs and in those with low allelic burden additional testing for JAK2 exon-12 and MPL exon-10 mutation should be pursued.

  20. Toward resolving the catalytic mechanism of dihydrofolate reductase using neutron and ultrahigh-resolution X-ray crystallography [Neutron and ultrahigh resolution X-ray crystallography reveals water as the proton donor in the catalytic mechanism of dihydrofolate reductase

    International Nuclear Information System (INIS)

    Dihydrofolate reductase (DHFR) catalyzes the NADPH-dependent reduction of dihydrofolate (DHF) to tetrahydrofolate (THF). An important step in the mechanism involves proton donation to the N5 atom of DHF. The inability to determine the protonation states of active site residues and substrate has led to the lack of consensus on a catalytic mechanism. To resolve this ambiguity, we conducted neutron and ultrahigh resolution X-ray crystallographic studies of the pseudo-Michaelis ternary complex of DHFR with folate and NADP+ from E. coli. The neutron data were collected to 2.0 Å resolution using a 3.6 mm3 crystal with the quasi-Laue technique, and the structure reveals that the N3 atom of folate is protonated while Asp27 is negatively charged. Previous mechanisms have proposed a keto-to-enol tautomerization of the substrate to facilitate protonation of the N5 atom. The structure supports the existence of the keto tautomer due to protonation of the N3 atom, suggesting tautomerization is unnecessary for catalysis. In the 1.05 Å resolution X-ray structure of the ternary complex, conformational disorder of the Met20 side chain is coupled to electron density for a partially occupied water within hydrogen-bonding distance of the N5 atom of folate; this suggests direct protonation of substrate by solvent. We propose a catalytic mechanism for DHFR that involves stabilization of the keto tautomer of the substrate, elevation of the pKa of the N5 atom of DHF by Asp27, and protonation of N5 by water whose access to the active site is gated by fluctuation of the Met20 side chain even though the Met-20 loop is closed

  1. EFFECTS OF FEED CONCENTRATION AND WATER VAPOR ON CATALYTIC COMBUSTION OF ETHYL ACETATE AND BENZENE IN AIR OVER CR-ZSM-5 CATALYST

    Directory of Open Access Journals (Sweden)

    Ahmad Zuhairi Abdullah

    2010-09-01

    Full Text Available Catalytic combustion of ethyl acetate (EAc and benzene (Bz over chromium exchanged ZSM-5 (Si/Al=240 is reported. An 11 mm i.d. fixed-bed catalytic reactor, operated at temperatures between 100 oC and 500 oC, and under excess oxygen condition, was used for the catalytic activity measurement. Apparent order of reaction and apparent activation energy were determined by operating the reactor differentially at a gas hourly space velocity (GHSV of 78,900 h-1 and feed concentrations between 3,500 ppm to 17,700 ppm and 3,700 to 12,400 ppm for ethyl acetate and benzene, respectively. Ethyl acetate was more reactive than benzene due to highly reactive carbonyl group in the molecule. The combustion process satisfactorily fitted pseudo first-order kinetics with respect to organic concentration and a zero-order dependence on the oxygen concentration. The presence of water vapor (9,000 ppm in the feed stream was found to weaken the reactivity of these organics which could also be demonstrated with increases in the activation energy from 23.1 kJ/mole to 37.6 kJ/mole for ethyl acetate and from 27.6 kJ/mole to 46.1 kJ/mole for benzene. Water vapor was found to play a positive role in the formation of carbon dioxide yield in ethyl acetate combustion. Deactivation of catalyst by water appeared to be only temporary and the activity reverted back to its original value once the source of water vapor was removed.

  2. Basic research for nuclear energy : a study on photo-catalytic decomposition reactions of organics dissolved in water

    International Nuclear Information System (INIS)

    In an experiment on TiO2 photo-catalysis of five nitrogen-containing organic compounds, the changes of pH and total carbon contents were measured, and the dependence of their photo-catalytic characteristic upon their chemical structures were investigated. -- calculation of the effect of ionic carbon species in an aqueous solution on thermodynamic equilibrium, pH and conductivity showed a small quantity of organics could lead conductivity increase and pH reduction. -- Based on the results of photo-catalytic experiment of ethylamine, phenylhydrazine, pyridine, urea or EDTA, irradiated for 180 minutes after adsorption onto titanium dioxide for 60 minutes, relationship between nitrogen atomic charge and the first-order rate constant was as the following: R (1st - order rate constant) = δ (ε - a )1/3 + b where, ε : atomic charge of nitrogen in a molecular, δ, a and b : corrective coefficients

  3. Photo Catalytic Oxidation of Alcohols in Water under Natural Weathering Conditions in the Presence of Bromo Source

    Institute of Scientific and Technical Information of China (English)

    P.H.Yan; R.R.Wang; J.Q.Wang; Y.X.Yang; S.Wu; H.Zhao; Z.Q.Lei

    2007-01-01

    1 Results The oxidation of alcohols into the corresponding carbonyl compound is one of the most important functional group transformation in organic synthesis[1]. Traditionally,such transformations have been performed with stoichiometric inorganic oxidant or other high valent metal oxidant[2]. Despite a variety of systems for the catalytic oxidation of alcohols have been developed,there is ongoing interest in the search for new efficient and environmental friendly oxidation system.To the best of our kno...

  4. Co-existent Paget’s Disease of the Bone, Prostate Carcinoma Skeletal Metastases and Fracture on Skeletal Scintigraphy-Lessons to be Learned

    Directory of Open Access Journals (Sweden)

    Luke I Sonoda

    2013-08-01

    Full Text Available Bone scintigraphy, despite being non-specific, is a very sensitive and simple investigation for patients with active Paget’s disease of the bone. Skeletal metastases and Paget’s disease may co-exist in the elderly patients as both conditions are commonly seen in this age group. Clinical and radiological correlation may help to improve the diagnostic specificity of a bone scintigram. We report a patient in whom concurrent Paget’s disease and a rib fracture became evident only on repeat scintigraphy following successful treatment of prostate carcinoma skeletal metastases.

  5. Mueller matrix analysis for all optical fiber co-existence of birefringence-polarization dependent gain-mode coupling at a single wavelength

    Institute of Scientific and Technical Information of China (English)

    Shang Chio; Wu Chong-Qing; Li Zheng-Yong; Yang Shuang-Shou; Gao Kai-Qiang; Yu Kuang-Lu; Feng Zhen

    2011-01-01

    Birefringence (polarization-related phase-shift),polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization (SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results,which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.

  6. Resolution of Ibuprofen Ester by Catalytic Antibodies in Water-miscible Organic-solvents%水-有机溶剂混溶体系中催化抗体催化拆分布洛芳脂

    Institute of Scientific and Technical Information of China (English)

    杨根生; 应黎; 欧志敏; 姚善泾

    2009-01-01

    The asymmetric hydrolysis of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. In this work, a catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was obtained against an immunogen consisting of tetrahedral phosphonatc hapten attached to bovine serum albumin (BSA). The catalytic activity of the catalytic antibody in the water-miscible organic-solvent system composed of a buffer solution and TV, .N-dimethylformamide (DMF) was studied. With 6% DMF in the buffer solution (containing catalytic antibody 0.25 umol, 0.2 mol·L-1 phosphate buffer, pH 8) at 37℃ for 10 h, a good conversion (48.7%) and high cnantiomeric excess (>99%) could be reached. The kinetic analysis of the cata-lytic antibody-catalyzed reaction showed that the hydrolysis in the water-miscible organic-solvent system with DMF in buffer solution followed the Michaelis-Menten kinetics. The catalytic efficiency (kcat/km) was enhanced to 151.91 L·mmol-1·min-1, twice as large as that for the buffer solution only.

  7. Engineered biochar from microwave-assisted catalytic pyrolysis of switchgrass for increasing water-holding capacity and fertility of sandy soil.

    Science.gov (United States)

    Mohamed, Badr A; Ellis, Naoko; Kim, Chang Soo; Bi, Xiaotao; Emam, Ahmed El-Raie

    2016-10-01

    Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand soil. The addition of K3PO4, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10wt.% K3PO4+10 wt.% clinoptilolite as catalysts to the soil at 2wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10wt.% clinoptilolite, respectively. Synergistic effects on increased soil WHC were manifested for biochars produced from combinations of two additives compared to single additive, which may be the result of increased biochar microporosity due to increased microwave heating rate. Biochar produced from microwave catalytic pyrolysis was more efficient in increasing the soil WHC due to its high porosity in comparison with the biochar produced from conventional pyrolysis at the same conditions. The increases in soil CEC varied widely compared to the control soil, ranging from 17 to 220% for the treatments with biochars produced with 10wt% clinoptilolite at 400°C, and 30wt% K3PO4 at 300°C, respectively. Strong positive correlations also exist among soil WHC with CEC and biochar micropore area. Biochar from microwave-assisted catalytic pyrolysis appears to be a novel approach for producing biochar with high sorption affinity and high CEC. These catalysts remaining in the biochar product would provide essential nutrients for the growth of bioenergy and food crops. PMID:27232966

  8. Removal of Mn{sup 2+} from water by 'aged' biofilter media: The role of catalytic oxides layers

    Energy Technology Data Exchange (ETDEWEB)

    Sahabi, D.M.; Takeda, M.; Suzuki, I.; Koizurni, J. [Yokohama National University, Kanagawa (Japan). Dept. of Chemical & Energy Engineering

    2009-02-15

    The present work was aimed at evaluating the surface coatings characteristics and autocatalytic manganese oxidation potentials of two groups of 'aged' biofilter media. This refers to the anthracite filter media of a biological water treatment plant on which metal oxides and a biofilm have deposited on the surface of the filter media over long time of filtration. Duplicate samples of anthracite filter media were collected from each of the six filter wells in the plant and classified into two groups, based on their duration of operation, as 3-years filter media and 15-years filter media. Batch experiments showed that the 15-years filter media exhibited very high manganese sorption capacity and were less dependent on the microbial activity than the 3-years filter media. Results of the surface coatings analyses indicated that the biofilter materials is predominantly composed of variable layers of manganese and iron oxides, with microbial biomass contributing only about 3.5 and 1.4% of the dry weight of the surface coatings on the 3- and 15-years filter media respectively. Investigations onto the Mn{sup 2+} sorption by the lyophilized biofilter media showed that, the sorption kinetics on the catalytic oxides layers followed the pseudo-second-order kinetics model, thus suggesting chemisorption as the dominant mechanism of Mn{sup 2+} removal. This implied that manganese removal by these biofilters is mainly by adsorption of Mn{sup 2+} onto the iron and manganese (catalytic) oxides layers and autocatalytic oxidation. The present study has clearly linked MN{sub 2}+ oxidation to the catalytic oxides layers on the aged biofilter media.

  9. IN-SITU MAGIC ANGLE SPINNING NMR INVESTIGATIONS ON CATALYTIC CONVERSION OF BIOGENIC MOLECULES IN THE PRESENCE OF AQUEOUS WATER

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Mary Y.; Feng, Ju; Camaioni, Donald M.; Turcu, Romulus VF; Peden, Charles HF; Lercher, Johannes A.; Hu, Jian Z.

    2012-09-01

    The catalyzed conversion of biomass to hydrocarbon energy carriers requires a cascade of reactions that deconstruct and reduce the polymeric, highly oxofunctionalized biomass material. While lignin is the most intractable component of lignocellulose, its conversion to useful products is key in this catalytic chemistry, because the carbon in lignin is the most reduced one in lignocellulose. This chemistry faces steep challenges, as most of the reactions have to be performed in an aqueous environment under conditions that are highly corrosive towards catalysts. The anticipated scale of the transformations demands that the complex catalysts involved be highly efficient, stable, regenerable, and economically viable catalysts. Currently, none of the known heterogeneous solid catalysts meets these requirements. In order to develop new catalysts satisfying these requirements, a fundamental understanding of the active centers, reaction intermediates and reaction dynamics/kinetics associated with the multi-step conversion of biomass/biomass components, or biomass related polar molecules, i.e., the precursor molecules to fuels, on multifunctional catalytic surfaces is critically needed.

  10. Catalytic activity of hydrophobic Pt/C/PTFE catalysts of different PTFE content for hydrogen-water liquid exchange reaction

    International Nuclear Information System (INIS)

    10%Pt/C catalysts were prepared by liquid reduction method. PTFE and Pt/ C catalysts were adhered to porous metal and hydrophobic Pt/C/PTFE catalysts were prepared. The structure and size of Pt crystal particles of Pt/C catalysts were analyzed by XRD, and their mean size was 3.1 nm. The dispersion state of Pt/C and PTFE was analyzed by SEM, and they had good dispersion mostly, but PTFE membrane could be observed on local parts of Pt/C/PTFE surface. Because of low hydrophobicity, Pt/C/ PTFE catalysts have low activity when the mass ratio of PTFE and Pt/C is 0.5: 1, and their catalytic activity increases markedly when the ratio is 1:1. When the ratio increases again, more Pt active sites would be covered by PTFE and interior diffusion effect would increase, which result in the decrease of catalytic activity of Pt/C/PTFE. By PTFE pretreatment of porous metal carrier, the activity of Pt/C/PTFE catalysts decreases when the mass ratio of PTFE and Pt/C is 0.5:1, and their activity decreases when the mass ratio is 1:1. (authors)

  11. Isotropic-Cholesteric Co-Existence and Magnetic Field-Induced Isotropic-Nematic Transition of Filamentous Bacteriophage FD in Aqueous Suspension.

    Science.gov (United States)

    Tang, Jianxin

    1995-01-01

    Isotropic to liquid crystalline phase transition for a lyotropic suspension of geometrically asymmetric macromolecules occurs to a wild class of synthetic polymers and biopolymers. Although in decades statistical mechanical theories have been developed to predict the thermodynamic conditions and the properties of such transition, quantitative comparison with theory has been compounded with complications such as charge, shape, polydispersity in size, and additional interactions with the solvent and among the macromolecules themselves. We chose the aqueous suspension of the filamentous bacteriophage fd as a model system to study the isotropic to liquid crystalline transition. The co-existence concentrations, as a function of ionic strength, were measured directly by spectrophotometry. Our data confirm quantitatively the predictions of a statistical mechanic treatment first described by Onsager, modified to include the effects of charge and flexibility of rodlike particles. We have also extended a previous study of the pretransitional angular correlations in the isotropic solutions of fd through the measurement of the magnetic-field-induced birefringence, i.e. the measurement of the Cotton-Mouton constant. At several ionic strengths the magnetic-field-induced birefringence, which is proportional to the number of particles in a correlation volume N_{rm corr}, was measured for fd concentrations spanning the entire isotropic region. From this data the limiting concentration of stability (spinodal) of the isotropic phase is obtained. A theoretical expression for the magnetic birefringence of persistent polymers was derived and agreed well with the data with the exception that N_{rm corr} at the isotropic to liquid crystal transition was smaller than predicted. In the proximity of the highest possible isotropic concentration, that is the isotropic in co-existence with anisotropic, we studied the effect of a high magnetic field. A first order field-induced isotropic

  12. Catalytic Kinetic Determination of Micro Amounts of Oxalic Acid by Second-Order Derivative Oscillopolarography

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K2Cr2O7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃. Orange Ⅳ exhibited a sensitive second-order derivative polarographic wave at -0.50 V(vs. SCE). This provides the basis for a sensitive and selective catalytic kinetic method for oxalate determination with second-order derivative oscillopolarography. The effects of sulphuric acid, K2Cr2O7, and orange Ⅳ concentrations, reaction temperature and reaction time were investigated. A calibration curve of oxalate in the range of 0.1—2.0 μg/mL was obtained by the fixed-time procedure. The detection limit was 0.03 μg/ mL. The possible interference from co-existing substances or ions was examined. The new method has a high sensitivity and a good selectivity compared to other existing methods for oxalic acid determination. It has been applied to the determination of micro amounts of oxalate in real urine samples with satisfactory results.

  13. Mn oxide coated catalytic membranes for a hybrid ozonation-membrane filtration: comparison of Ti, Fe and Mn oxide coated membranes for water quality.

    Science.gov (United States)

    Byun, S; Davies, S H; Alpatova, A L; Corneal, L M; Baumann, M J; Tarabara, V V; Masten, S J

    2011-01-01

    In this study the performance of catalytic membranes in a hybrid ozonation-ceramic membrane filtration system was investigated. The catalytic membranes were produced by coating commercial ceramic ultrafiltration membranes with manganese or iron oxide nanoparticles using a layer-by-layer self-assembly technique. A commercial membrane with a titanium oxide filtration layer was also evaluated. The performance of the coated and uncoated membranes was evaluated using water from a borderline eutrophic lake. The permeate flux and removal of the organic matter was found to depend on the type of the metal oxide present on the membrane surface. The performance of the manganese oxide coated membrane was superior to that of the other membranes tested, showing the fastest recovery in permeate flux when ozone was applied and the greatest reduction in the total organic carbon (TOC) in the permeate. The removal of trihalomethanes (THMs) and haloacetic acids (HAAs) precursors using the membrane coated 20 times with manganese oxide nanoparticles was significantly better than that for the membranes coated with 30 or 40 times with manganese oxide nanoparticles or 40 times with iron oxide nanoparticles. PMID:20822791

  14. A Mi’kmaw Perspective on Advancing Salmon Governance in Nova Scotia, Canada: Setting the Stage for Collaborative Co-Existence

    Directory of Open Access Journals (Sweden)

    Shelley K. Denny

    2016-09-01

    Full Text Available Issues related to fisheries governance are a source of debate and tension between the Indigenous Mi’kmaq people of Nova Scotia and the Canadian Department of Fisheries and Oceans (DFO in matters concerning Atlantic salmon, Salmo salar. Within the context of the existing governance regime, this analysis compares the concept of salmon conservation and management from a Mi’kmaq perspective and proposes a collaborative co-existence approach for effective salmon governance in Nova Scotia. This approach begins by using co-management as a process, Two-Eyed Seeing as the design, and treaties as the model to achieve shared objectives of maintaining and improving abundances of salmon populations, in spite of differing mechanisms for addressing the interwoven complexities of multiple realities, conservation, and cultural identity.

  15. Influence of co-existed benzo[a]pyrene and copper on the cellular characteristics of Stenotrophomonas maltophilia during biodegradation and transformation.

    Science.gov (United States)

    Chen, Shuona; Yin, Hua; Ye, Jinshao; Peng, Hui; Liu, Zehua; Dang, Zhi; Chang, Jingjing

    2014-04-01

    Microbial remediation has been proposed as a promising technique to remove pollutions, however, its application has been hindered by the lack of understanding the mechanisms involved in contaminants conversion and the influence of pollutants on cellular characteristics. To address this problem, biodegradation and transformation of BaP-Cu(II) by Stenotrophomonas maltophilia, along with interactions of these pollutants with microbial cells through FCM assay were investigated. The results indicated that BaP and Cu(II) were rapidly removed by S. maltophilia on the 1st d, but only less than 10% BaP was broken down due to temporary store in cells, instead of being decomposed immediately. The key ATP enzymes in cells were then activated by BaP to promote bacteria to further decompose BaP. Stimulation of co-existed contaminants strengthened cell membrane permeability and altered cell structure, but a higher esterase activity and DNA in cells of S. maltophilia were still retained.

  16. Distribution and co-existence of the Macropis species and their cleptoparasite Epeoloides coecutiens (Fabr.) in NW Europe Hymenoptera: Apoidea, Melittidae and Apidae)

    DEFF Research Database (Denmark)

    Pekkarinen, Antti; Berg, Øistein; Calabuig, Isabel;

    2003-01-01

    The Macropis species collect pollen and fatty oil secreted by flowers of loosestrifes (Lysimachia, Primulaceae) and are the only known oil-collecting bees in the Holarctic. In NW Europe, L. vulgaris is the main or (in large areas) sole pollen and oil source for M. europaea Warncke (labiata auct.......) and M. fulvipes (Fabr.). The species are largely sympatric in southern Finland and the Baltic countries, while in Scandinavia and most of Denmark only M. europaea has been recorded. The ranges of the Macropis species are restricted to the areas of common occurrence of L. vulgaris. Presumably, Epeoloides...... coecutiens has colonized Finland and Estonia since about 1970. The phenology of M. fulvipes is some days earlier than that of M. europaea, and this temporal difference may decrease resource competition in the co-existing populations....

  17. Co-existence of Two Different α-Synuclein Oligomers with Different Core Structures Determined by Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Paslawski, Wojciech; Mysling, Simon; Thomsen, Karen;

    2014-01-01

    and structure. Hydrogen/deuterium exchange (HDX) monitored by mass spectrometry is used to analyze oligomers formed by wild-type (wt) αSN and also three familial αSN mutants (A30P, E46K, and A53T). All four variants show co-existence of two different oligomers. The backbone amides of oligomer type I...... are protected from exchange with D2 O until they dissociate into monomeric αSN by EX1 exchange kinetics. Fewer residues are protected against exchange in oligomer type II, but this type does not revert to αSN monomers. Both oligomers are protected in the core sequence Y39-A89. Based on incubation studies...

  18. Co-existence of urinary tract infection and malaria among children under five years old: A report from Benin City, Nigeria

    Directory of Open Access Journals (Sweden)

    P O Okunola

    2012-01-01

    Full Text Available Children with fever are a majority in the various emergency rooms all over the world, and especially in the tropics. Most in sub-Saharan Africa will be treated for malaria, whether confirmed or not. It therefore follows that some of the morbidities other than malaria may go undiagnosed. The comorbidities with malaria that may have similar presentation among under-fives therefore are difficult to detect, and diseases like respiratory tract infections and urinary tract infections (UTI are left to debilitate affected children. The exact burden of UTI co-existing with malaria in Nigeria remains ill defined. This study looks at the co-existence of UTI in under- fives with a primary diagnosis of malaria. Well-nourished children aged less than five years with confirmed malaria seen at the Children Emergency Room of the University of Benin Teaching Hospital were recruited into a prospective cross-sectional study between June and August 2006. The prevalence of UTI was 9% (27 of 300 children, with those aged less than 24 months comprising the majority. The uropathogens isolated included Staphylococcus aureus (55.6%, Escherichia coli (29.6% and Kleibsiella pneumonia (14.8%. The isolates demonstrated high in vitro sensitivity to clavulanic acid-potentiated amoxicillin, ciprofloxacin and gentamicin, but were resistant to other commonly used antibiotics like amoxicillin and co-trimoxazole. The study indicates that UTI is a silent comorbidity in children aged less than 5 years with malaria and there is a need to evaluate these children in order to prevent the long-term morbidity of chronic renal diseases.

  19. Mechanism of Catalytic Water Oxidation by the Ruthenium Blue Dimer Catalyst: Comparative Study in D2O versus H2O

    Directory of Open Access Journals (Sweden)

    Yulia Pushkar

    2013-01-01

    Full Text Available Water oxidation is critically important for the development of energy solutions based on the concept of artificial photosynthesis. In order to gain deeper insight into the mechanism of water oxidation, the catalytic cycle for the first designed water oxidation catalyst, cis,cis-[(bpy2(H2ORuIIIORuIII(OH2(bpy2]4+ (bpy is 2,2-bipyridine known as the blue dimer (BD, is monitored in D2O by combined application of stopped flow UV-Vis, electron paramagnetic resonance (EPR and resonance Raman spectroscopy on freeze quenched samples. The results of these studies show that the rate of formation of BD[4,5] by Ce(IV oxidation of BD[3,4] (numbers in square bracket denote oxidation states of the ruthenium (Ru centers in 0.1 M HNO3, as well as further oxidation of BD[4,5] are slower in D2O by 2.1–2.5. Ce(IV oxidation of BD[4,5] and reaction with H2O result in formation of an intermediate, BD[3,4]′, which builds up in reaction mixtures on the minute time scale. Combined results under the conditions of these experiments at pH 1 indicate that oxidation of BD[3,4]′ is a rate limiting step in water oxidation with the BD catalyst.

  20. Improvement of catalytic activity in selective oxidation of styrene with H{sub 2}O{sub 2} over spinel Mg–Cu ferrite hollow spheres in water

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Jinhui, E-mail: jinhuitong@126.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Lanzhou 730070 (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Cai, Xiaodong; Wang, Haiyan; Zhang, Qianping [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Lanzhou 730070 (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2014-07-01

    Graphical abstract: Uniform spinel Mg–Cu ferrite hollow spheres were prepared using carbon spheres as templates. Solid spinel Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} ferrite nanocrystals were also prepared by sol–gel auto-combustion, hydrothermal and coprecipitation methods for comparison. The samples were found to be efficient catalysts for oxidation of styrene using hydrogen peroxide as oxidant. Especially, in the case of Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} hollow spheres, obvious improvement on catalytic activity was observed and 21.2% of styrene conversion and 75.2% of selectivity for benzaldehyde were obtained at 80 °C for 6 h reaction in water. The catalyst can be magnetically separated easily for reuse and no obvious loss of activity was observed when reused in six consecutive runs. - Highlights: • Uniform spinel ferrite hollow spheres were prepared by a simple method. • The catalyst has been proved much more efficient for styrene oxidation than the reported analogues. • The catalyst can be easily separated by external magnetic field and has exhibited excellent reusability. • The catalytic system is environmentally friendly. - Abstract: Uniform spinel Mg–Cu ferrite hollow spheres were prepared using carbon spheres as templates. For comparison, solid Mg–Cu ferrite nanocrystals were also prepared by sol–gel auto-combustion, hydrothermal and coprecipitation methods. All the samples were characterized by Fourier transform infrared spectrophotometry (FT-IR), X-ray diffractometry (XRD), transmission electron microscopy (TEM) and N{sub 2} physisorption. The samples were found to be efficient catalysts for oxidation of styrene using hydrogen peroxide as oxidant. Especially, in the case of Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} hollow spheres, obvious improvement on catalytic activity was observed, and 21.2% of styrene conversion and 75.2% of selectivity for benzaldehyde were obtained at 80 °C for 6 h reaction in water. The catalyst can be

  1. Co-existence of Paragonimus harinasutai and Paragonimus bangkokensis metacercariae in fresh water crab hosts in central Viet Nam with special emphasis on their close phylogenetic relationship.

    Science.gov (United States)

    Doanh, Pham Ngoc; Hien, Hoang Van; Nonaka, Nariaki; Horii, Yoichiro; Nawa, Yukifumi

    2012-09-01

    During our epidemiological surveys for Paragonimus species in central Viet Nam, we found four morphologically different Paragonimus metacercariae in mountainous crabs. They were identified as metacercariae of Paragonimus westermani, P. bangkokensis, P. proliferus, and P. harinasutai in the order of their prevalence in crab hosts. This is the first discovery of P. harinasutai in Viet Nam, co-inhabiting with P. bangkokensis and other species. Metacercariae of P. harinasutai were given orally to a cat to obtain adult worms. Then, ITS2 and CO1 sequences of metacercariae and adults of P. harinasutai, and metacercariae of P. bangkokensis collected from the same place were determined for analyses of phylogenetic relationships to other P. harinasutai and P. bangkokensis populations as well as related species. The results of molecular analyses showed that P. harinasutai from Quang Binh province of central Viet Nam was almost completely identical with those from Vientiane, Lao PDR; P. bangkokensis from Quang Binh, Viet Nam was also almost completely identical with those from Lao PDR and from Quang Ninh province, Viet Nam. Except for one P. harinasutai isolate from China, all populations of P. harinasutai and P. bangkokensis from Thailand, Lao and Viet Nam make a single clade in both ITS2 and CO1 trees. In ITS2 sequences, AT deletion and ATC insertion were observed in some isolates of both species, indicating recent gene flow between P. harinasutai and P. bangkokensis. Moreover, because of their extremely high genetic similarities and their co-inhabitation in the same crab hosts found in Thailand, Lao PDR and Viet Nam, they should be considered as the sister species at the early stage of divergence. In addition, P. microrchis previously described from Yunnan, China should be placed as the synonym of P. harinasutai, because of their morphological and molecular similarities.

  2. [State of Fungal Lipases of Rhizopus microsporus, Penicillium sp. and Oospora lactis in Border Layers Water-Solid Phase and Factors Affecting Catalytic Properties of Enzymes].

    Science.gov (United States)

    Khasanov, Kh T; Davranov, K; Rakhimov, M M

    2015-01-01

    We demonstrated that a change in the catalytic activity of fungal lipases synthesized by Rhizopus microsporus, Penicillium sp. and Oospora lactis and their ability to absorb on different sorbents depended on the nature of groups on the solid phase surface in the model systems water: lipid and water: solid phase. Thus, the stability of Penicillium sp. lipases increased 85% in the presence ofsorsilen or DEAE-cellulose, and 55% of their initial activity respectively was preserved. In the presence of silica gel and CM-cellulose, a decreased rate of lipid hydrolysis by Pseudomonas sp. enzymes was observed in water medium, and the hydrolysis rate increased by 2.4 and 1.5 times respectively in the presence of aminoaerosil and polykefamid. In an aqueous-alcohol medium, aminoaerosil and polykefamid decreased the rate of substrate hydrolysis by more than 30 times. The addition of aerosil to aqueous and aqueous-alcohol media resulted in an increase in the hydrolysis rate by 1.2-1.3 times. Sorsilen stabilized Penicillium sp. lipase activity at 40, 45, 50 and 55 degrees C. Either stabilization or inactivation of lipases was observed depending on the pH of the medium and the nature of chemical groups localized on the surface of solid phase. The synthetizing activity of lipases also changed depending on the conditions.

  3. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-09-19

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields.

  4. [State of Fungal Lipases of Rhizopus microsporus, Penicillium sp. and Oospora lactis in Border Layers Water-Solid Phase and Factors Affecting Catalytic Properties of Enzymes].

    Science.gov (United States)

    Khasanov, Kh T; Davranov, K; Rakhimov, M M

    2015-01-01

    We demonstrated that a change in the catalytic activity of fungal lipases synthesized by Rhizopus microsporus, Penicillium sp. and Oospora lactis and their ability to absorb on different sorbents depended on the nature of groups on the solid phase surface in the model systems water: lipid and water: solid phase. Thus, the stability of Penicillium sp. lipases increased 85% in the presence ofsorsilen or DEAE-cellulose, and 55% of their initial activity respectively was preserved. In the presence of silica gel and CM-cellulose, a decreased rate of lipid hydrolysis by Pseudomonas sp. enzymes was observed in water medium, and the hydrolysis rate increased by 2.4 and 1.5 times respectively in the presence of aminoaerosil and polykefamid. In an aqueous-alcohol medium, aminoaerosil and polykefamid decreased the rate of substrate hydrolysis by more than 30 times. The addition of aerosil to aqueous and aqueous-alcohol media resulted in an increase in the hydrolysis rate by 1.2-1.3 times. Sorsilen stabilized Penicillium sp. lipase activity at 40, 45, 50 and 55 degrees C. Either stabilization or inactivation of lipases was observed depending on the pH of the medium and the nature of chemical groups localized on the surface of solid phase. The synthetizing activity of lipases also changed depending on the conditions. PMID:26596088

  5. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-01-01

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields. PMID:27657143

  6. The catalytic role of the water or acidic zeolite in the oxidation of BrCH2OH. A theoretical study

    Science.gov (United States)

    Papayannis, Demetrios K.; Kosmas, Agnie M.

    2016-11-01

    We present a computational investigation of the catalytic activity of the water molecules or acidic zeolite in the oxidation of bromomethanol, coming from the degradation of brominated organic compounds in the natural environment. The role of the water in this mechanism has been established using MP2(full)/6-311++G(3df, 2p) level of theory. Energetic results were further refined by CCSD(T) calculations, using optimized geometric parameters of the MP2 level. The computational investigation shows clearly the dramatic reduction of the activation energy of the oxidation to formaldehyde that occurs when explicit coordination of water molecules is taken into account. Further investigation of the degradation mechanism has been carried out by considering the oxidation reaction as taking place on acidic zeolite surface, with the help of the hybrid (QM/MM) approximation and specifically the two-layered, ONIOM2 methodology at the (MP2(full)/6-31G∗:UFF) and (M06-2X/6-311++G(3df, 2p):UFF) levels of theory.

  7. Science Letters: Structure relationship of nitrochlorobenzene catalytic degradation process in water over palladium-iron bimetallic catalyst

    Institute of Scientific and Technical Information of China (English)

    NIU Shao-feng; ZHOU Hong-yi; AO Xu-ping; XU Xin-hua; LOU Zhang-hua

    2006-01-01

    Two isomers of nitrochlorobenzene (o-, and p-NCB) were treated by a Pd/Fe catalyst in aqueous solutions through catalytic amination and dechlorination. Nitrochlorobenzenes are rapidly converted to form chloroanilines (CAN) first through an amination process, and then rapidly dechlorinated to become aniline (AN) and Cl-, without the involvement of any other intermediate reaction products. The amination and dechlorination reaction are believed to take place predominantly on the surface site of the Pd/Fe catalysts. The dechlorination rate of the reductive degradation of the two isomers of nitrochlorobenzene (o-, and p-NCB) in the presence of Pd/Fe as a catalyst was measured experimentally. In all cases, the reaction rate constants were found to increase with the decrease in the Gibbs free energy (correlation with the activation energy) of NCBs formation; the activation energy of each dechlorination reaction was measured to be 95.83 and 77.05 kJ/mol, respectively for o- and p-NCB. The results demonstrated that p-NCBs were reduced more easily than o-NCBs.

  8. Thermal desorption study of catalytic systems. Communication 20. Adsorption of water vapors on the calcium aluminate components of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, V.D.; Danyushevskii, V.Y.; Golosman, E.Z.; Rubinstein, A.M.; Yakerson, V.I.

    1985-05-01

    Ca aluminates are used as a component of catalysts of gas-phase processes, some of which take place with the participation of water. Nickel calcium aluminate catalysts are thus used for hydrogenation of CO and CO/sub 2/ to CH/sub 4/ and water; zinc calcium aluminate catalysts are used for sulfur purification of process gases, where water is liberated during sulfiding of ZnO; and copper zinc calcium aluminate catalysts are used in low-temperature conversion of CO with water vapor. It is also known that Ca aluminates undergo various transformations in aqueous media with the formation of Ca hydroaluminates. This paper discusses the adsorption of water from the gas phase on calcium aluminate systems, which was investigated by the thermal desorption method. Samples of varying phase composition, different CaO/Al/sub 2/O/sub 3/ ratios, and specific surface areas were also studied and are reported on here.

  9. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  10. Enhancement of reaction rates for catalytic benzaldehyde hydrogenation and sorbitol dehydration in water solvent by addition of carbon dioxide

    Indian Academy of Sciences (India)

    Masayuki Shirai; Osamu Sato; Norihito Hiyoshi; Aritomo Yamaguchi

    2014-03-01

    The effect of pressured carbon dioxide on heterogeneous hydrogenation of benzaldehyde and homogeneous dehydration of sorbitol in water solvent was studied. Initial hydrogenation rates of benzaldehyde over a charcoal-supported palladium catalyst in water at 313 K were enhanced by the addition of carbon dioxide. The initial rate increased with an increase in carbon dioxide pressure and became a maximum at 5 MPa. Dehydration of sorbitol proceeded in water phase at 500 K and initial dehydration rates were enhanced by addition of 30 MPa of carbon dioxide.

  11. On the co-existence of chemically peculiar Bp stars, slowly pulsating B stars and constant B stars in the same part of the H-R diagram

    CERN Document Server

    Briquet, M; De Cat, P; Aerts, C; North, P; Scholler, M; 10.1051/0004-6361:20066940

    2009-01-01

    Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of the H-R diagram. Methods. We carry out a comparative study between samples of confirmed and well-studied SPB stars and a sample of well-studied Bp stars with known periods and magnetic field strengths. We determine their evolutionary state using accurate HIPPARCOS parallaxes and Geneva photometry. We discuss the occurrence and strengths of magnetic fields as well as the occurrence of stellar pulsation among both groups. Further, we make a comparison of Geneva photometric variability for both kinds of stars. Results. The group of Bp stars is significantly younger than the group of SPB stars. Longitudinal magnetic fields in SPB stars are weaker than those of Bp stars, suggesting that the magnetic field strength is an important factor for B type stars to become chemically pec...

  12. Treated Nanolayered Mn Oxide by Oxidizable Compounds: A Strategy To Improve the Catalytic Activity toward Water Oxidation.

    Science.gov (United States)

    Mahdi Najafpour, Mohammad; Jafarian Sedigh, Davood; Maedeh Hosseini, Seyedeh; Zaharieva, Ivelina

    2016-09-01

    Herein, we investigate the effect of post-treatment of nanolayered manganese oxide by different inorganic and organic compounds. We use the fact that nanolayered manganese oxides are among the strongest naturally occurring oxidants, capable of oxidizing a wide range of organic molecules. Post-treatment of the synthetic Mn oxides with oxidizable compounds increases the cerium(IV)-driven water oxidation catalyzed by treated layered manganese oxides more than 25 times. On the basis of X-ray absorption investigations, we attribute this effect to the increased amount of manganese(III) ions. This finding can explain some puzzles in water oxidation by manganese oxides and may help to advance toward an efficient design strategy of water-oxidizing catalyst in artificial photosynthetic systems. PMID:27537432

  13. Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis

    Science.gov (United States)

    Yu, Yu; Li, Pei; Wang, Xiaofang; Gao, Wenyu; Shen, Zongxu; Zhu, Yanan; Yang, Shuliang; Song, Weiguo; Ding, Kejian

    2016-05-01

    Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity. Electronic supplementary information (ESI) available: More SEM, TEM images, XRD patterns, LSV curves, XPS spectra. See DOI: 10.1039/c6nr02395a

  14. Bifunctional catalytic electrode

    Science.gov (United States)

    Cisar, Alan (Inventor); Murphy, Oliver J. (Inventor); Clarke, Eric (Inventor)

    2005-01-01

    The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reduction of oxygen to water, and has a structure that supports the flow of both water and gases between the catalytically active surface and a flow field or electrode chamber for bulk flow of the fluids. The electrode has an electrocatalyst layer and a diffusion backing layer interspersed with hydrophilic and hydrophobic regions. The diffusion backing layer consists of a metal core having gas diffusion structures bonded to the metal core.

  15. The use of ozonation and catalytic ozonation combined with ultrafiltration for the control of natural organic matter (NOM) and disinfection by-products (DBPs) in drinking water

    Science.gov (United States)

    Karnik, Bhavana Sushilkumar

    Commercially available titania membranes, with a molecular weight cut-off of 15, 5, 1 kD were used in a ozonation/membrane system that was fed with water from Lake Lansing. The effects of ozonation on permeate flux recovery and membrane fouling was investigated. In addition the effects of ozonation/membrane filtration hybrid process on the removal of the natural organic matter (NOM) and the formation of disinfection by-products (DBPS) were monitored. The commercial membrane (CeRAM Inside, Tami North America, St. Laurent, Quebec, Canada) was coated with iron oxide nanoparticles (4--6 nm in diameter) using a layer-by-layer technique and sintered in air for 30 minutes. Surface characterization was carried out using electron microscopy techniques and atomic force microscopy, to study the changes in structure and surface morphology of the membranes. The removal and survival of bacteria in the process was also evaluated using fluorescence microscopy and microbial assays. Finally the surface catalytic reaction was investigated to propose the mechanism responsible for the improved performance of the hybrid process. The permeate flux through a titania coated ceramic membrane was significantly affected by ozonation. A minimum threshold ozone concentration (2.5 g/m 3) could achieve complete recovery of permeate flux after fouling. Ozonation/filtration decreased the concentration of chlorinated disinfection by-products up to 80%. With catalyst coated membranes, the concentration of dissolved organic carbon was reduced by >85% and the concentrations of disinfection by-products decreased by up to 90%. Furthermore with the coated membrane, the concentrations of ozonation by-products in the permeate were reduced by >50% as compared to that obtained with the uncoated membranes, thus reducing the risk of potential regrowth of bacteria in the distribution system. Application of the hybrid process lead to greater than 7 log removal of bacteria. Surface characterization showed that

  16. Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films

    KAUST Repository

    Sun, Ke

    2015-03-11

    Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g). © 2015, National Academy of Sciences. All rights reserved.

  17. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P.; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G.; Kazantzis, Nikolaos K.; Ma, Yi Hua

    2016-01-01

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields. PMID:27657143

  18. Co-existence of calcium-binding proteins and γ-aminobutyric acid or glycine in neurons of the rat medullary dorsal horn

    Institute of Scientific and Technical Information of China (English)

    王文; 武胜昔; 李云庆

    2004-01-01

    Background We investigated the co-expression of calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV, a combination of the three is referred to as CaBPs) with γ-aminobutyric acid (GABA) or glycine in neurons of the rat medullary dorsal horn (MDH).Methods Immunofluorescence histochemical double-staining for CaBPs and GABA or glycine was performed on the sections from rat MDH.Results CB-, CR-, PV-, GABA- and glycine-like immunoreactive (LI) neurons were differentially observed in all layers of the MDH, but particularly in lamina Ⅱ. Neurons that exhibited immunoreactivity for both CaBPs and GABA or glycine were also observed mainly in lamina Ⅱ. A few of them were found in laminae I and III. The percentages of neurons which co-expressed CB/GABA or CB/glycine out of the total numbers of CB- and GABA-LI neurons or CB- and glycine-LI neurons were 5.3% and 12.1% or 4.1% and 10.0%, respectively. The ratios of CR/GABA or CR/glycine co-existing neurons out of the total numbers of CR- and GABA-LI neurons or CR- and glycine-LI neurons were 5.8% and 7.6% or 4.4% and 7.1%, respectively. The rates of PV/GABA or PV/glycine co-localized neurons out of the total numbers of PV- and GABA-LI neurons or PV- and glycine-LI neurons were 11.1% and 5.1% or 9.9% and 5.1%, respectively. Conclusion The results indicate that some neurons in the MDH contain both CaBPs and GABA or glycine.

  19. Modelling Niche Differentiation of Co-Existing, Elusive and Morphologically Similar Species: A Case Study of Four Macaque Species in Nakai-Nam Theun National Protected Area, Laos

    Directory of Open Access Journals (Sweden)

    Camille N. Z. Coudrat

    2013-01-01

    Full Text Available Species misidentification often occurs when dealing with co-existing and morphologically similar species such as macaques, making the study of their ecology challenging. To overcome this issue, we use reliable occurrence data from camera-trap images and transect survey data to model their respective ecological niche and potential distribution locally in Nakai-Nam Theun National Protected Area (NNT NPA, central-Eastern Laos. We investigate niche differentiation of morphologically similar species using four sympatric macaque species in NNT NPA, as our model species: rhesus Macaca mulatta (Taxonomic Serial Number, TSN 180099, Northern pig-tailed M. leonina (TSN not listed; Assamese M. assamensis (TSN 573018 and stump-tailed M. arctoides (TSN 573017. We examine the implications for their conservation. We obtained occurrence data of macaque species from systematic 2006–2011 camera-trapping surveys and 2011–2012 transect surveys and model their niche and potential distribution with MaxEnt software using 25 environmental and topographic variables. The respective suitable habitat predicted for each species reveals niche segregation between the four species with a gradual geographical distribution following an environmental gradient within the study area. Camera-trapping positioned at many locations can increase elusive-species records with a relatively reduced and more systematic sampling effort and provide reliable species occurrence data. These can be used for environmental niche modelling to study niche segregation of morphologically similar species in areas where their distribution remains uncertain. Examining unresolved species' niches and potential distributions can have crucial implications for future research and species' management and conservation even in the most remote regions and for the least-known species.

  20. Water-soluble metal nanoparticles stabilized by plant polyphenols for improving the catalytic properties in oxidation of alcohols

    Science.gov (United States)

    Mao, H.; Liao, Y.; Ma, J.; Zhao, S. L.; Huo, F. W.

    2015-12-01

    Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic conditions, the as-prepared BWT-Pt colloid catalyst exhibited high activity in a series of biphasic oxidation of aromatic alcohols and aliphatic alcohols. As for the cycling stability, the BWT-Pt catalyst showed no obvious decrease during the 7 cycles, revealing superior cycling stability as compared with the counterparts using PVP or PEG as the stabilizer.Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic

  1. Water-soluble metal nanoparticles stabilized by plant polyphenols for improving the catalytic properties in oxidation of alcohols.

    Science.gov (United States)

    Mao, H; Liao, Y; Ma, J; Zhao, S L; Huo, F W

    2016-01-14

    Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic conditions, the as-prepared BWT-Pt colloid catalyst exhibited high activity in a series of biphasic oxidation of aromatic alcohols and aliphatic alcohols. As for the cycling stability, the BWT-Pt catalyst showed no obvious decrease during the 7 cycles, revealing superior cycling stability as compared with the counterparts using PVP or PEG as the stabilizer. PMID:26662453

  2. An efficient route for catalytic activity promotion via hybrid electro-depositional modification on commercial nickel foam for hydrogen evolution reaction in alkaline water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Guanshui; He, Yongwei; Wang, Mei; Zhu, Fuchun; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); Wang, Xiaoguang, E-mail: wangxiaog1982@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); International Iberian Nanotechnology Laboratory (INL), 4715-330 Braga (Portugal)

    2014-09-15

    Highlights: • Mono-Cu surface modification depress the HER activity of Ni-foam. • Hybrid Ni-foam/Cu0.01/Co0.05 exhibits superior HER performance. • Layer-by-layer structure may contribute to a synergistic promoting effect. - Abstract: In this paper, the single- and hybrid-layered Cu, Ni and Co thin films were electrochemically deposited onto the three-dimensional nickel foam as composite cathode catalyst for hydrogen evolution reaction in alkaline water electrolysis. The morphology, structure and chemical composition of the electrodeposited composite catalysts were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Electrochemical measurement depicted that, for the case of the monometallic layered samples, the general activity for hydrogen evolution reaction followed the sequence: Ni-foam/Ni > Ni-foam/Co > bare Ni-foam > Ni-foam/Cu. It is noteworthy that, the hybrid-layered Ni-foam/Cu0.01/Co0.05 exhibited the highest catalytic activity towards hydrogen evolution reaction with the current density as high as 2.82 times that of the bare Ni-foam. Moreover, both excellent electrochemical and physical stabilities can also be acquired on the Ni-foam/Cu0.01/Co0.05, making this hybrid-layered composite structure as a promising HER electro-catalyst.

  3. Phase Behaviour of 1-Ethyl-3-methylimidazolium Thiocyanate Ionic Liquid with Catalytic Deactivated Compounds and Water at Several Temperatures: Experiments and Theoretical Predictions

    Directory of Open Access Journals (Sweden)

    Ramalingam Anantharaj

    2011-01-01

    Full Text Available Density, surface tension and refractive index were determined for the binary mixture of catalytic deactivated compounds with 1-ethyl-3-methylimidazolium thiocyanate {[EMIM][SCN]} at temperature of (298.15 to 323.15 K. For all the compounds with ILs, the densities varied linearly in the entire mole fraction with increasing temperature. From the obtained data, the excess molar volume and deviation of surface tension and refractive index have been calculated. A strong interaction was found between similar (cation-thiophene or cation-pyrrole compounds. The interaction of IL with dissimilar compounds such as indoline and quinoline and other multiple ring compounds was found to strongly depend on the composition of IL at any temperatures. For the mixtures, the surface tension decreases in the order of: thiophene > quinoline > pyridine > indoline > pyrrole > water. In general from the excess volume studies, the IL-sulphur/nitrogen mixture has stronger interaction as compared to IL-IL, thiophene-thiophene or pyrrole-pyrrole interaction. The deviation of surface tension was found to be inversely proportional to deviation of refractive index. The quantum chemical based COSMO-RS was used to predict the non-ideal liquid phase activity coefficient for all mixtures. It indicated an inverse relation between activity coefficient and excess molar volumes.

  4. Effect of doping β-NiOOH with Co on the catalytic oxidation of water: DFT+U calculations.

    Science.gov (United States)

    Costanzo, Francesca

    2016-03-14

    Electrocatalytic water splitting using energy from sunlight represents a promising strategy for clean, low-cost, and environmentally friendly production of H2. Unfortunately, the oxygen evolution reaction (OER) at the anode is kinetically slow and represents the bottleneck of this process. Transition metal oxides are good candidates for the anode in electrochemical water splitting. Inspired by recent computational work on β-NiOOH, which is considered the active phase during the charging and discharging process in alkaline batteries, we performed density functional theory calculations with the inclusion of the Hubbard-U correction on selected surfaces of pure and Co-doped β-NiOOH to calculate the energetics of the OER. The goal of the paper is to investigate theoretically whether doping a NiOOH surface with Co might change the mechanism and lower the overpotential of the OER on a specific NiOOH surface, and to what extent the choice of the surface unit cell may affect the results. Our results indicate that the most likely reaction mechanism depends on the amount of Co doping. We find that doping the β-NiOOH surface with only 25% Co decreases the overpotential from 0.28 to 0.18 V. We also find that the theoretical overpotential, and which step is the potential limiting step, depends on the size of the surface unit cell selected in the calculations. This work highlights how optimizing the binding energies of the various intermediates (O, OH and H2O) on the Ni and Co surface sites, may be key to reducing the overpotential. PMID:26902752

  5. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  6. CATALYTIC PROPERTY OF DOUBLE LAYERED PEROVSKITES A2MM’O6 FOR RADIOLYTICAL SPLIT OF WATER

    Directory of Open Access Journals (Sweden)

    Alexandru Cecal

    2009-06-01

    Full Text Available This paper deals with a study of water splitting by gamma rays in the presence of some double perovskites A2MM’O6 and also Sr2Fe1-xTa1+xO6. The irradiation is performed using 60Co as a source with 3·104 Ci activity and 8.3 kGy/h dose rate, which simulated the radioactive wastes, resulted from reprocessing of spent nuclear fuel elements much more active: 108-109 Ci. The stable products of radiolysis, as well as the other chemical species are measured by mass spectrometry. The calculated radiation yield (GH2 generally decreases in the order: Sr2Fe1-xTa1+xO6 (x=0.5; 0.4; 0.3; 0.1 > Ca2AlTaO6 > Sr2AlTaO6 > Ba2AlTaO6, under the given experimental conditions; the yield was higher in the presence of these catalysts than in their absence.

  7. Catalytic supercritical water gasification of primary paper sludge using a homogeneous and heterogeneous catalyst: Experimental vs thermodynamic equilibrium results.

    Science.gov (United States)

    Louw, Jeanne; Schwarz, Cara E; Burger, Andries J

    2016-02-01

    H2, CH4, CO and CO2 yields were measured during supercritical water gasification (SCWG) of primary paper waste sludge (PWS) at 450°C. Comparing these yields with calculated thermodynamic equilibrium values offer an improved understanding of conditions required to produce near-equilibrium yields. Experiments were conducted at different catalyst loads (0-1g/gPWS) and different reaction times (15-120min) in a batch reactor, using either K2CO3 or Ni/Al2O3-SiO2 as catalyst. K2CO3 up to 1g/gPWS increased the H2 yield significantly to 7.5mol/kgPWS. However, these yields and composition were far from equilibrium values, with carbon efficiency (CE) and energy recovery (ER) of only 29% and 20%, respectively. Addition of 0.5-1g/gPWS Ni/Al2O3-SiO2 resulted in high H2 and CH4 yields (6.8 and 14.8mol/kgPWS), CE of 84-90%, ER of 83% and a gas composition relatively close to the equilibrium values (at hold times of 60-120min). PMID:26638140

  8. Catalytic property of double layered perovskites A2MM'O6 for radiolytic split of water

    International Nuclear Information System (INIS)

    This paper deals with a study of water splitting by gamma rays in the presence of some double perovskites A2MM'O6 and also Sr2Fe1-xTa1+xO6. The irradiation is performed using 60Co as a source with 3x104 Ci activity and 8.3 kGy/h dose rate, which simulated the radioactive wastes, resulted from reprocessing of spent nuclear fuel elements much more active: 108-109 Ci. The stable products of radiolysis, as well as the other chemical species are measured by mass spectrometry. The calculated radiation yield (GH2) generally decreases in the order: Sr2Fe1-xTa1+xO6 (x=0.5; 0.4; 0.3; 0.1) > Ca2AlTaO6 > Sr2AlTaO6 > Ba2AlTaO6, under the given experimental conditions; the yield was higher in the presence of these catalysts than in their absence. (authors)

  9. Photosynthesis of co-existing Phragmites haplotypes in their non-native range: are characteristics determined by adaptations derived from their native origin?

    Science.gov (United States)

    Nguyen, Loc Xuan; Lambertini, Carla; Sorrell, Brian K.; Eller, Franziska; Achenbach, Luciana; Brix, Hans

    2013-01-01

    The Gulf Coast of North America (GC) is a ‘hot spot’ of Phragmites diversity as several lineages (defined according to the haplotypes of their chloroplast DNA) differing in origin, genetic traits and phenotype co-exist and interbreed in this area. We analysed differences in photosynthetic characteristics among and within four haplotypes to understand if differences in gas exchange can be attributed to adaptations acquired in their native ranges. We collected rhizomes of four GC haplotypes (I2, M1, M and AI; including the phenotypes ‘Land-type’, ‘Delta-type’, ‘EU-type’ and ‘Greeny-type’) and propagated them in a common controlled environment to compare photosynthesis–irradiance responses, CO2 responses, chlorophyll fluorescence, the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), specific leaf area (SLA), pigment contents, stomatal density and guard cell length. The maximum light-saturated photosynthetic rate, Amax, in the haplotype I2 (Land-type) and haplotype M1 (Delta-type) (34.3–36.1 µmol CO2 m−2 s−1) was higher than that in the invasive Eurasian haplotype M (22.4 ± 2.3 µmol CO2 m−2 s−1). The Amax of haplotype AI (Greeny3-type) was 29.1 ± 4.0 µmol CO2 m−2 s−1 and did not differ from the Amax of the other haplotypes. The carboxylation rate (Vcmax) and electron transport rate (Jmax) followed the same pattern as Amax. The haplotypes also differed in SLA (17.0–24.3 m2 kg−1 dry mass) and pigment content, whereas stomatal density and guard cell length, Rubisco activity and chlorophyll fluorescence did not differ significantly among haplotypes. The high photosynthetic activity and gas-exchange capacity of the two haplotypes originating in tropical Africa and the Mediterranean area (haplotypes I2 and M1) are apparently adaptations derived from their native ranges. Hence, the haplotypes can be regarded as ecotypes. However, it remains unclear how these differences relate to plant competitiveness and

  10. 完全性葡萄胎与胎儿共存临床研究%Clinical study of complete hydatidiform mole and co-existing fetus

    Institute of Scientific and Technical Information of China (English)

    李珠玉; 陈海天; 彭软; 王子莲; 游泽山

    2015-01-01

    Objective To explore the clinical characteristics and pregnancy outcomes of complete hy-datidiform mole and co-existing fetus (CMCF).Methods The data of six CMCF women were analyzed retro-spectively.Results Among six CMCF women,five were pregnant after in vitro fertilization and embryo trans-plantation,and one after ovulation-stimulating treatment.Five patients were diagnosed with CMCF in middle pregnancy and one in early pregnancy.Five cases had twin pregnancy with complete hydatidiform mole and one was triplet pregnanct.One case insisted on continuous pregnancy,four accepted pregnancy termination and one was forced to terminate pregnancy.All six women and one fetus survived.Conclusions The incidence of CM-CF is probably correlated with the application of assisted reproductive technology.Clinical outcomes depend on disease progression,fetal chromosome and patients’willingness.If the fetal chromosome is normal and no seri-ous maternal complications occur during pregnancy,the fetus may survive.However,the risk of continuous pregnancy remains to be evaluated.%目的:探讨完全性葡萄胎与胎儿共存(CMCF)的临床特征及妊娠结局。方法收集并分析6例 CMCF 的临床资料。结果6例中,体外受精-胚胎移植术后妊娠5例,促排卵治疗后妊娠1例;妊娠中期发现5例,妊娠早期发现1例;双胎之一完全性葡萄胎5例,三胎之一完全性葡萄胎1例;要求继续妊娠1例,要求终止妊娠4例,被迫终止妊娠1例。6例产妇均存活,胎儿存活1例。结论CMCF 的发生可能与应用辅助生殖技术相关,其结局取决于病情发展、胎儿染色体及患者意愿。若胎儿染色体正常,且妊娠期间未出现严重母体并发症,有分娩活胎可能,但其继续妊娠的风险评估仍需进一步的研究。

  11. Connections between 5-HT-containing terminals and 5-HT2A receptor and γ-aminobutyric acid or glycine co-existed neurons in the rat medullary dorsal horn

    Institute of Scientific and Technical Information of China (English)

    LI Hui; LI Yun-qing

    2001-01-01

    Objective: To investigate the connections between serotonin (5-HT)-containing terminals and 5-HT2A receptor (5-HT2AR)/γ-aminobutyric acid (GABA) or 5-HT2AR/glycine co-existed neurons in the rat medullary dorsal horn (MDH).Methods: Immunofluorescence histochemical triple-staining for 5-HT, 5-HT2AR, GABA or glycine. Results: 5-HT-immunoreaetive fibers and terminals were chiefly located in the superficial laminae (laminae Ⅰ and Ⅱ) of the MDH. Neurons exhibiting 5-HT2AR-, GABA- or glycine-immunoreactivities were mainly observed in the superficial laminae. Some 5-HT2AR-immunopositive neurons also exhibited GABA- or glycine-immunoreaetivities. 5-HT-containing terminals made close contacts with 5-HT2AR/GABA or 5-HT2AR/glycine co-existed neurons. Conclusion: 5-HT2AR/GABA or 5-HT2AR /glycine co-exist in some of the neurons in the superficial laminae of the MDH. 5-HT-immunoreactive terminals form close connections with 5-HT2AR/GABA or 5-HT2AR/glycine co-existed neurons.

  12. Impact of water quality on removal of carbamazepine in natural waters by N-doped TiO{sub 2} photo-catalytic thin film surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Avisar, Dror, E-mail: drorvi@post.tau.ac.il [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); Horovitz, Inna [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Lozzi, Luca; Ruggieri, Fabrizio [Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, I-67010 Coppito, L’Aquila (Italy); Baker, Mark; Abel, Marie-Laure [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Mamane, Hadas [School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2013-01-15

    Highlights: ► N-doped TiO{sub 2} thin films have been deposited by sol–gel dip-coating. ► CBZ removal improved with increasing medium pH in the range of 5–9. ► DOC at a concentration of 5 mg/L resulted in an ∼20% reduction in CBZ removal. ► Alkalinity values of 100 mg/L as CaCO{sub 3} resulted in a 40% decrease in CBZ removal. ► Complete suppression of the photocatalytic process in wastewater effluent. -- Abstract: Photocatalytic experiments on the pharmaceutical pollutant carbamazepine (CBZ) were conducted using sol–gel nitrogen-doped TiO{sub 2}-coated glass slides under a solar simulator. CBZ was stable to photodegradation under direct solar irradiation. No CBZ sorption to the catalyst surface was observed, as further confirmed by surface characterization using X-ray photoelectron spectroscopic analysis of N-doped TiO{sub 2} surfaces. When exposing the catalyst surface to natural organic matter (NOM), an excess amount of carbon was detected relative to controls, which is consistent with NOM remaining on the catalyst surface. The catalyst surface charge was negative at pH values from 4 to 10 and decreased with increasing pH, correlated with enhanced CBZ removal with increasing medium pH in the range of 5–9. A dissolved organic carbon concentration of 5 mg/L resulted in ∼20% reduction in CBZ removal, probably due to competitive inhibition of the photocatalytic degradation of CBZ. At alkalinity values corresponding to CaCO{sub 3} addition at 100 mg/L, an over 40% decrease in CBZ removal was observed. A 35% reduction in CBZ occurred in the presence of surface water compared to complete suppression of the photocatalytic process in wastewater effluent.

  13. Preparation of Pt/K2La2Ti3O10 and its photo-catalytic activity for hydrogen evolution from methanol water solution

    Institute of Scientific and Technical Information of China (English)

    CUI; Wenquan

    2006-01-01

    ):A new series of layered perovskites exhibiting ion exchange,Inorg.Chem.,1987,26:4299-4301.[12]Takata,T.,Shinohara,K.,Tanaka,A.,Hara,M.,Kondo,J.N.,Domen,K.,A highly active photocatalyst for overall water splitting with a hydrated layered perovskite structure,J.Photochem.Photobiol.A:Chem.,1997,106(1-3):45-49.[13]Cui,W.Q.,Feng,L.R.,Xu,C.H.,Lü,S.J.,Qiu,F.L.,Hydrogen production by photocatalytic decomposition of methanol gas on Pt/TiO2 nano-film,Catal.Comm.,2004(5):533-536.[14]Herrmann,J.M.,Disdier,J.,Pichat,P.,Photoassisted platinum deposition on TiO2 powder using various platinum complexes,J.Phys.Chem.,1986,90:6028-6034.[15]Cui,W.Q.,Feng,L.R.,Xu,C.H.,Lü,S.J.,Qiu,F.L.,Studies on the photo-catalytic decomposition of methanol vapor on Pt-loaded nano-TiO2 particles,Acta Chim.Sinica (in Chinese),2005,63(3):203-209.[16]Ikeda,S.,Hara,M.,Kondo,J.N.,Domen,K.,Preparation of K2La2Ti3O10 by polymerized complex method and photocatalytic decomposition of water,Chem.Mater.,1998,10(1):72-77.[17]Yang,X.Y.,Per,Z.F.,Bai,R.Q.,Studies on dispersion of Pt by HOT,Petrochemical Technology,1978,7(4):352.[18]Fox,M.A.,Dulay,M.Y.,Heterogeneous photocatalysis,Chem.Rev.,1993,93(1):341-357.[19]Kudo,A.,Sakata,T.,Luminescent properties of nondoped and rare earth metal ion-doped K2La2Ti3O10 with layered perovskite structures:Importance of the hole trap process,J.Phys.Chem.,1995,99:15963-15967.

  14. Diurnal and Seasonal Changes in Stem Radius Increment and Sap Flow Density Indicate Different Responses of Two Co-existing Oak Species to Drought Stress

    Directory of Open Access Journals (Sweden)

    MÉSZÁROS, Ilona

    2011-01-01

    Full Text Available Using continuous monitoring of stem radius combined with sap flow measurements weassessed the effects of environmental conditions on tree radial growth and water status of two coexistingoak species (Quercus petraea and Quercus cerris at high resolution time in growingseasons of 2008 and 2009. The forest (95–100 yr is situated in a xeric site in the transition zonebetween forested and forest-steppe regions in north-eastern Hungary, Bükk mountains (47o90’N,20o46’E, elevation 320–340 m a.s.l.. Weather conditions in the growing season of 2008 (totalrainfall 354 mm, mean daily temperature 17.0 oC was less extreme than in 2009 (total rainfall299 mm, temperature 17.9 oC. Rainfall strongly determined the course of radial growth incrementin trees. Radial growth of trees was limited in 2009 due to the drought in spring. The maximumradial increment of both species was achieved three weeks earlier (4th week of June than in 2008(4th week of July. We used dendrometer monitoring data for estimation of stem (tree waterdeficit (W by measuring water-related changes in stem radius (Zweifel et al. 2005. Themagnitude of tree water deficit variation (W was always smaller in Q. cerris than in Q. petraea.In contrast, Quercus cerris always exhibited larger daytime averages and maxima of sap flowdensity. In August of 2009 when drought became severe there were larger increases in tree waterdeficit (W (50–55 % in both species compared to July as it could be expected from the extentof decreases in sap flow density (24–28%. Our data suggested that due to the low SWC thetranspiration was supported mainly from the inner water storage of trees during prolonged droughtwhich resulted in high stem water deficit (W.

  15. Application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant%催化燃烧技术在炼油污水处理场恶臭治理中的应用

    Institute of Scientific and Technical Information of China (English)

    刘永斌; 程俊梅; 程彬彬

    2011-01-01

    介绍了催化燃烧技术在炼油污水处理场恶臭治理中的应用情况.工业应用表明,催化燃烧技术适用于处理石化炼油污水场总进水口、隔油池、浮选池等散发的恶臭气体,废气处理效果良好.恶臭治理设施运行后,对硫化物的去除率达95%以上,对硫化氢的去除率接近100%,对总烃的去除率达到85%以上,净化后的气体能够满足国家排放标准的要求.催化燃烧技术治理恶臭污染项目的实施,对同类型炼化装置将起到借鉴作用.%The application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant was introduced. The catalytic combustion technology was applicable for the treatment of foul gases from water inlet of refinery waste water treatment plant, API separator, flotation pit, etc with good results. After operation of foul gas treatment facilities, the sulfide removal rate is over 95% , the H2S removal rate is close to 100% and total hydrocarbons removal rate is more than 85%. The purified gas meets China national emission standards. The implementation of foul gas treatment facilities using catalytic combustion technology provides a good reference for the operation of similar refinery process units.

  16. Catalytic distillation structure

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1984-01-01

    Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

  17. Catalytic combustor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mercea, J.; Grecu, E.; Fodor, T.; Kreibik, S.

    1982-01-01

    The performance of catalytic combustors for hydrogen using platinum-supported catalysts is described. Catalytic plates of different sizes were constructed using fibrous and ceramic supports. The temperature distribution as well as the reaction efficiency as a function of the fuel input rate was determined, and a comparison between the performances of different plates is discussed.

  18. Catalytic gasification of biomass

    Science.gov (United States)

    Robertus, R. J.; Mudge, L. K.; Sealock, L. J., Jr.; Mitchell, D. H.; Weber, S. L.

    1981-12-01

    Methane and methanol synthesis gas can be produced by steam gasification of biomass in the presence of appropriate catalysts. This concept is to use catalysts in a fluidized bed reactor which is heated indirectly. The objective is to determine the technical and economic feasibility of the concept. Technically the concept has been demonstrated on a 50 lb per hr scale. Potential advantages over conventional processes include: no oxygen plant is needed, little tar is produced so gas and water treatment are simplified, and yields and efficiencies are greater than obtained by conventional gasification. Economic studies for a plant processing 2000 T/per day dry wood show that the cost of methanol from wood by catalytic gasification is competitive with the current price of methanol. Similar studies show the cost of methane from wood is competitive with projected future costs of synthetic natural gas. When the plant capacity is decreased to 200 T per day dry wood, neither product is very attractive in today's market.

  19. Light-toned salty soils and co-existing Si-rich species discovered by the Mars Exploration Rover Spirit in Columbia Hills

    Science.gov (United States)

    Wang, Alian; Bell, J.F.; Li, Ron; Johnson, J. R.; Farrand, W. H.; Cloutis, E.A.; Arvidson, R. E.; Crumpler, L.; Squyres, S. W.; McLennan, S.M.; Herkenhoff, K. E.; Ruff, S.W.; Knudson, A.T.; Chen, Wei; Greenberger, R.

    2008-01-01

    Light-toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences were grouped into four types on the basis of geomorphic settings. At three major exposures, the light-toned soils are hydrous and sulfate-rich. The spatial distributions of distinct types of salty soils vary substantially: with centimeter-scaled heterogeneities at Paso Robles, Dead Sea, Shredded, and Champagne-Penny, a well-mixed nature for light-toned soils occurring near and at the summit of Husband Hill, and relatively homogeneous distributions in the two layers at the Tyrone site. Aeolian, fumarolic, and hydrothermal fluid processes are suggested to be responsible for the deposition, transportation, and accumulation of these light-toned soils. In addition, a change in Pancam spectra of Tyrone yellowish soils was observed after being exposed to current Martian surface conditions for 175 sols. This change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface. Si-rich nodules and soils were observed near the major exposures of S-rich soils. They possess a characteristic feature in Pancam visible near-infrared (Vis-NIR) spectra that may be diagnostic of hydrated species, and this spectral feature can be used to search for additional Si-rich species. The exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area. Hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the Neutron Spectrometer on Mars Odyssey.

  20. Water-Driven Assembly of Laser Ablation-Induced Au Condensates as Mesomorphic Nano- and Micro-Tubes

    Directory of Open Access Journals (Sweden)

    Chen Shuei-Yuan

    2009-01-01

    Full Text Available Abstract Reddish Au condensates, predominant atom clusters and minor amount of multiply twinned particles and fcc nanoparticles with internal compressive stress, were produced by pulsed laser ablation on gold target in de-ionized water under a very high power density. Such condensates were self-assembled as lamellae and then nano- to micro-diameter tubes with multiple walls when aged at room temperature in water for up to 40 days. The nano- and micro-tubes have a lamellar- and relaxed fcc-type wall, respectively, both following partial epitaxial relationship with the co-existing multiply twinned nanoparticles. The entangled tubes, being mesomorphic with a large extent of bifurcation, flexibility, opaqueness, and surface-enhanced Raman scattering, may have potential encapsulated and catalytic/label applications in biomedical systems.

  1. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  2. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the diffusi

  3. Catalytic ignition of light hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    K. L. Hohn; C.-C. Huang; C. Cao

    2009-01-01

    Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional extemai heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.

  4. Catalytic coherence transformations

    Science.gov (United States)

    Bu, Kaifeng; Singh, Uttam; Wu, Junde

    2016-04-01

    Catalytic coherence transformations allow the otherwise impossible state transformations using only incoherent operations with the aid of an auxiliary system with finite coherence that is not being consumed in any way. Here we find the necessary and sufficient conditions for the deterministic and stochastic catalytic coherence transformations between a pair of pure quantum states. In particular, we show that the simultaneous decrease of a family of Rényi entropies of the diagonal parts of the states under consideration is a necessary and sufficient condition for the deterministic catalytic coherence transformations. Similarly, for stochastic catalytic coherence transformations we find the necessary and sufficient conditions for achieving a higher optimal probability of conversion. We thus completely characterize the coherence transformations among pure quantum states under incoherent operations. We give numerous examples to elaborate our results. We also explore the possibility of the same system acting as a catalyst for itself and find that indeed self-catalysis is possible. Further, for the cases where no catalytic coherence transformation is possible we provide entanglement-assisted coherence transformations and find the necessary and sufficient conditions for such transformations.

  5. Catalytic Decomposition of Methylene Chloride by Sulfated Titania Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Catalytic decomposition of methylene chloride in air below 300℃ was studied.Sulfated titania was very effective in converting 959ppm methylene chloride selectively to CO,CO2 and HCl.Complete decomposition of methylene chloride was achieved at low temperature(275℃).It was found that the acidic property of catalyst was a determinant factor for the catalytic activity.The presence of water vapor in the feed stream remarkably reduced the catalytic activity,which could be due to the blockage of acidic sites on the surface of catalyst by water molecules.A bifunctional catalyst comprising copper oxide was developed to improve the selectivity of catalytic oxidation,which indicated that copper oxide can promote the deep oxidation of methylene chloride.The crystal form of TiO2 imposes an important influence upon the catalytic oxidation.

  6. Characterization of N-acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger rhizosphere: Co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia

    Directory of Open Access Journals (Sweden)

    Chhabra Siri

    2011-03-01

    Full Text Available Abstract Background Cell-to-cell communication (quorum sensing (QS co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ activities. Here we sought to discover novel N-acylhomoserine lactone (AHL-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale growing in the Malaysian rainforest. Results By using a basal growth medium containing N-(3-oxohexanoylhomoserine lactone (3-oxo-C6-HSL as the sole source of carbon and nitrogen, the ginger rhizosphere associated bacteria were enriched for strains with AHL-degrading capabilities. Three isolates belonging to the genera Acinetobacter (GG2, Burkholderia (GG4 and Klebsiella (Se14 were identified and selected for further study. Strains GG2 and Se14 exhibited the broadest spectrum of AHL-degrading activities via lactonolysis while GG4 reduced 3-oxo-AHLs to the corresponding 3-hydroxy compounds. In GG2 and GG4, QQ was found to co-exist with AHL-dependent QS and GG2 was shown to inactivate both self-generated and exogenously supplied AHLs. GG2, GG4 and Se14 were each able to attenuate virulence factor production in both human and plant pathogens. Conclusions Collectively our data show that ginger rhizosphere bacteria which make and degrade a wide range of AHLs are likely to play a collective role in determining the QS-dependent phenotype of a polymicrobial community.

  7. Influence of humic substances on the removal of pentachlorophenol by a biomimetic catalytic system with a water-soluble iron(III)-porphyrin complex.

    Science.gov (United States)

    Fukushima, Masami; Sawada, Akira; Kawasaki, Mikio; Ichikawa, Hiroyasu; Morimoto, Kengo; Tatsumi, Kenji; Aoyama, Masakazu

    2003-03-01

    To investigate some basic aspects of soil remediation using biomimetic catalysts, the effects of humic substances (HSs) on the removal of xenobiotics, such as pentachlorophenol (PCP), were investigated. The use of a biomimetic catalytic system using tetra(p-sulfophenyl)porphine-iron(III) (Fe(III)-TPPS) and potassium monopersulfate (KHSO5) resulted in the disappearance of PCP, accompanied by dechlorination. In addition, this process was enhanced by the presence of several types of HSs. The degrees of enhancement (% delta(PCP)60) achieved by the presence of HSs from peat and compost soils were larger than those in the presence of other types of HSs (tropical peat, brown forest, and ando soils). In control experiments, no PCP disappearance and dechlorination were observed in the presence of only KHSO5, only Fe(III)-TPPS, or combinations of HSs and either KHSO5 or Fe(III)-TPPS. To better understand the role of added HS in enhancing or inhibiting PCP disappearance, correlations between the chemical parameters of the HSs and % delta(PCP)60 were investigated. The most effective HSs had lower carboxylic acid contents and lower degrees of unsaturation. The carboxylic acid content and degree of unsaturation increase with the extent of humification. Therefore, HSs of a lower degree of humification would be predicted to be more useful in enhancing the disappearance of PCP in an Fe(III)-TPPS/KHSO5 system. PMID:12666937

  8. 高级催化氧化法去除水中邻苯二甲酸酯的研究进展%Removal of phthalic acid esters from water by advanced catalytic oxidation process

    Institute of Scientific and Technical Information of China (English)

    刘静; 李亚茹; 王杰; 陈凯凯

    2014-01-01

    Generally, phthalic acid esters(PAEs) are considered to be endocrine disrupting chemicals (EDCs). This substance is widely used in plasticizers, cosmetics, etc. PAEs would give rise to malformation, cancerization and mutation as well as possess quasi/anti-estrogen activity and quasi/resistance-thyroid hormone activity. PAEs could spread to the environment easily and be detected in the soil, air and water. They are common pollutants in the environment, which pose serious threats to both human health and the ecological environment. As a result, PAEs have attracted widespread attention at home and abroad. This paper summarizes the physi-chemical properties and toxic effects of PAEs and analyses the pollution status in natural water, groundwater and wastewater. The work also discusses many recent methods developed to remove PAEs, such as enhanced coagulation, adsorption, membrane treatment, biological treatment, advanced oxidation process, etc. Advanced oxidation technology has attracted much attention and developed rapidly because of it’s ability to remove different kinds of organic pollutants quickly and efficiently from drinking water and sewage. This article introduces the degradation of PAEs in water mainly using advanced oxidation technology which includes the catalytic wet peroxide oxidation, the catalytic ozone oxidation, photocatalytic oxidation, ultrasonic and microwave assisted catalytic oxidation and advanced nanometer catalytic oxidation. Fenton catalytic oxidation process could produce highly reactive hydroxyl radicals by adding catalyst and UVradiation in the process of oxidation. This method could achieve the highest oxidation efficiency as well as degrade PAEs into non-toxic harmless chemicals completely and non-selectively. Although application of the catalyst in advanced oxidation process can improve the oxidation efficiency and the degradation degree greatly, this method needs a huge amount of catalyst and energy and also influenced by pH value

  9. Catalytic Conversion of Biofuels

    DEFF Research Database (Denmark)

    Jørgensen, Betina

    This thesis describes the catalytic conversion of bioethanol into higher value chemicals. The motivation has been the unavoidable coming depletion of the fossil resources. The thesis is focused on two ways of utilising ethanol; the steam reforming of ethanol to form hydrogen and the partial oxida...

  10. Catalytic Phosphination and Arsination

    Institute of Scientific and Technical Information of China (English)

    Kwong Fuk Yee; Chan Kin Shing

    2004-01-01

    The catalytic, user-friendly phosphination and arsination of aryl halides and triflates by triphenylphosphine and triphenylarsine using palladium catalysts have provided a facile synthesis of functionalized aryl phosphines and arsines in neutral media. Modification of the cynaoarisne yielded optically active N, As ligands which will be screened in various asymmetric catalysis.

  11. Catalytic efficiency of designed catalytic proteins.

    Science.gov (United States)

    Korendovych, Ivan V; DeGrado, William F

    2014-08-01

    The de novo design of catalysts that mimic the affinity and specificity of natural enzymes remains one of the Holy Grails of chemistry. Despite decades of concerted effort we are still unable to design catalysts as efficient as enzymes. Here we critically evaluate approaches to (re)design of novel catalytic function in proteins using two test cases: Kemp elimination and ester hydrolysis. We show that the degree of success thus far has been modest when the rate enhancements seen for the designed proteins are compared with the rate enhancements by small molecule catalysts in solvents with properties similar to the active site. Nevertheless, there are reasons for optimism: the design methods are ever improving and the resulting catalyst can be efficiently improved using directed evolution.

  12. The true nature of the Di-iron(III) gamma-Keggin structure in water: catalytic aerobic oxidation and chemistry of an unsymmetrical trimer.

    Science.gov (United States)

    Botar, Bogdan; Geletii, Yurii V; Kögerler, Paul; Musaev, Djamaladdin G; Morokuma, Keiji; Weinstock, Ira A; Hill, Craig L

    2006-08-30

    The complex [gamma(1,2)-SiW(10){Fe(OH(2))}(2)O(38)](6)(-) (1) has been reported to catalyze the much sought reductant-free selective O(2)-based epoxidation of alkenes (Nishiyama, Y.; Nakagawa, Y.; Mizuno, N. Angew. Chem. Int. Ed. 2001, 40, 3639-3641) in chlorocarbon-acetonitrile solution. The challenge of reproducing catalysis by 1 led us to examine this chemistry in detail. In H(2)O, a desirable solvent for catalysis, 1, does not exist in the proposed organic-medium form in which the two iron atoms are in the binding pocket defined by the equatorial oxygens and, importantly, by two oxygens bound to the central Si heteroatom. Instead, 1 in H(2)O initially forms an unusual trimer [{Fe(2)(OH)(3)(H(2)O)(2)}(3)(gamma-SiW(10)O(36))(3)](15)(-) (2). The X-ray structure of 2 shows that the Fe-O(Si) bonds are cleaved and new bonds (mu-hydroxo bridges) form between these Fe centers and those of the neighboring [gamma(1,2)-SiW(10)Fe(2)] units. Structural, physical, and computational evidence indicate that if the bonds between the d-electron center, M (Fe in the case of 1 and 2), and the terminal ligands on M are stronger than the M-O(x)() bonds, then the out-of-pocket form is more stable and is the one observed. Significantly, 2 in H(2)O forms an intermediate that catalyzes the effective aerobic oxidation of sulfur compounds (mercaptoethanol is oxidized to the corresponding disulfide by O(2) at ambient pressure and temperature). All experimental findings are consistent with dissociation of a gamma-SiW(10) Keggin unit from the trimer, 2, to form the catalytically active species. PMID:16925446

  13. Formation and characterization of water-soluble hydrido-ruthenium(II) complexes of 1,3,5-triaza-7-phosphaadamantane and their catalytic activity in hydrogenation of CO2 and HCO3- in aqueous solution.

    Science.gov (United States)

    Laurenczy, G; Joó, F; Nádasdi, L

    2000-10-30

    The water-soluble tertiary phosphine complex of ruthenium(II), [RuCl2(PTA)4], (PTA = 1,3,5-triaza-7-phosphaadamantane) was used as catalyst precursor for hydrogenation of CO2 and bicarbonate in aqueous solution, in the absence of amine or other additives, under mild conditions. Reaction of [RuCl2(PTA)4] and H2 (60 bar) gives the hydrides [RuH2(PTA)4] (at pH = 12.0) and [RuH(PTA)4X] (X = Cl- or H2O) (at pH = 2.0). In presence of excess PTA, formation of the unparalleled cationic pentakis-phosphino species, [HRu(PTA)5]+, was unambiguously established by 1H and 31P NMR measurements. The same hydrides were observed when [Ru(H2O)6][tos]2 (tos = toluene-4-sulfonate) reacted with PTA under H2 pressure. The rate of CO2 hydrogenation strongly depends on the pH. The highest initial reaction rate (TOF = 807.3 h(-1)) was determined for a 10% HCO3-/90% CO2 mixture (pH = 5.86), whereas the reduction was very slow both at low and high pH (CO2 and Na2CO3 solutions, respectively). 1H and 31P NMR studies together with the kinetic measurements suggested that HCO3- was the real substrate and [RuH(PTA)4X] the catalytically active hydride species in this reaction. Hydrogenation of HCO3- showed an induction period which could be ascribed to the slow formation of the catalytically active hydride species. PMID:11233205

  14. Nano sponge Mn₂O ₃ as a new adsorbent for the preconcentration of Pd(II) and Rh(III) ions in sea water, wastewater, rock, street sediment and catalytic converter samples prior to FAAS determinations.

    Science.gov (United States)

    Yavuz, Emre; Tokalıoğlu, Serife; Sahan, Halil; Patat, Saban

    2014-10-01

    In this study, a nano sponge Mn2O3 adsorbent was synthesized and was used for the first time. Various parameters affecting the recovery values of Pd(II) and Rh(III) were examined. The tolerance limits (≥ 90 %) for both Pd(II) and Rh(III) ions were found to be 75,000 mg L(-1) Na(I), 75,000 mg L(-1) K(I), 50,000 mg L(-1) Mg(II) and 50,000 mg L(-1) Ca(II). A 30s contact time was enough for both adsorption and elution. A preconcentration factor of 100 was obtained by using 100mg of the nano sponge Mn2O3. The reusability of the adsorbent was 120 times. Adsorption capacities for Pd(II) and Rh(III) were found to be 42 and 6.2 mg g(-1), respectively. The detection limits were 1.0 µg L(-1) for Pd(II) and 0.37 µg L(-1) for Rh(III) and the relative standard deviations (RSD, %) were found to be ≤ 2.5%. The method was validated by analyzing the standard reference material, SRM 2556 (Used Auto Catalyst Pellets) and spiked real samples. The optimized method was applied for the preconcentration of Pd(II) and Rh(III) ions in water (sea water and wastewater), rock, street sediment and catalytic converter samples. PMID:25059126

  15. Rapid disinfection of E-Coliform contaminated water using WO3 semiconductor catalyst by laser-induced photo-catalytic process.

    Science.gov (United States)

    Gondal, Mohammed A; Khalil, Amjad

    2008-04-01

    Laser-induced photo-catalysis process using WO(3) semiconductor catalyst was applied for the study of disinfection effectiveness of E-coliform-contaminated water. For this purpose, wastewater polluted with E-coliform bacteria was exposed to 355 nm UV radiations generated by third harmonic of Nd: YAG laser in special glass cell with and without WO(3) catalyst. E-Coliform quantification was performed by direct plating method to obtain the efficiency of each disinfection treatment. The dependence of disinfection process on laser irradiation energy, amount of catalyst and duration of laser irradiation was also investigated. The disinfection with WO(3) was quite efficient inactivating E-coliforms. For inactivation of E-coliforms, less than 8 minutes' laser irradiation was required, so that, the treated water complies with the microbial standards for drinking water. This study opens the possibility of application of this simple method in rural areas of developing countries using solar radiation. PMID:18324535

  16. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  17. A catalytic cracking process

    Energy Technology Data Exchange (ETDEWEB)

    Degnan, T.F.; Helton, T.E.

    1995-07-20

    Heavy oils are subjected to catalytic cracking in the absence of added hydrogen using a catalyst containing a zeolite having the structure of ZSM-12 and a large-pore crystalline zeolite having a Constraint Index less than about 1. The process is able to effect a bulk conversion of the oil at the same time yielding a higher octane gasoline and increased light olefin content. (author)

  18. Advances in gas flow metering - end of the history, peaceful co-existence or a new beginning; Les avancees dans le mesurage des debits de gaz - fin de l'histoire, coexistence pacifique ou nouveau commencement

    Energy Technology Data Exchange (ETDEWEB)

    Studzinski, W. [NOVA Research and Technology Centre, Calgary (Canada)

    2000-07-01

    Gas flow metering plays an important role in the technical and fiscal operations of pipeline systems. Over the last hundred years, the industry has gone through several technical revolutions. The recent two decades were characterized by the introduction of flow computers in the 80's and acceptance of ultrasonic meters in the 90's. These changes, associated with measurement technology, have had a profound impact on pipeline operation, deregulation of the gas industry and gas trading. Significant advances were made, however, it is certainly not the end for progress in gas flow metering. The future development of optoelectronic and mass flow meters combined with advances in telemetry and tele-calibration may significantly reduce capital and maintenance costs. Classical flow meters will be upgraded to a new level of performance and will co-exist with the newest technologies. The uncertainty of flow measurement will be improved, mainly in terms of stability over longer periods of time. Old and new meters will be able to perform in environments other than dry natural gas. Processing of flow measurement data will evolve with the progress in flow computers and smart transmitters. The advances in gas flow metering will be driven by life cycle cost reduction as well as new business and service requirements. (author)

  19. Microstructural and compositional change of NaOH-activated high calcium fly ash by incorporating Na-aluminate and co-existence of geopolymeric gel and C–S–H(I)

    KAUST Repository

    Oh, Jae Eun

    2012-05-01

    This study explores the reaction products of alkali-activated Class C fly ash-based aluminosilicate samples by means of high-resolution synchrotron X-ray diffraction (HSXRD), scanning electron microscope (SEM), and compressive strength tests to investigate how the readily available aluminum affects the reaction. Class C fly ash-based aluminosilicate raw materials were prepared by incorporating Na-aluminate into the original fly ashes, then alkali-activated by 10 M NaOH solution. Incorporating Na-aluminate reduced the compressive strength of samples, with the reduction magnitude relatively constant regardless of length of curing period. The HSXRD provides evidence of the co-existence of C-S-H with geopolymeric gels and strongly suggests that the C-S-H formed in the current system is C-S-H(I). The back-scattered electron images suggest that the C-S-H(I) phase exists as small grains in a finely intermixed form with geopolymeric gels. Despite providing extra source of aluminum, adding Na-aluminate to the mixes did not decrease the Si/Al ratio of the geopolymeric gel. © 2012 Elsevier Ltd.

  20. Structures of the Ca2+-regulated photoprotein obelin Y138F mutant before and after bioluminescence support the catalytic function of a water molecule in the reaction.

    Science.gov (United States)

    Natashin, Pavel V; Ding, Wei; Eremeeva, Elena V; Markova, Svetlana V; Lee, John; Vysotski, Eugene S; Liu, Zhi-Jie

    2014-03-01

    Ca(2+)-regulated photoproteins, which are responsible for light emission in a variety of marine coelenterates, are a highly valuable tool for measuring Ca(2+) inside living cells. All of the photoproteins are a single-chain polypeptide to which a 2-hydroperoxycoelenterazine molecule is tightly but noncovalently bound. Bioluminescence results from the oxidative decarboxylation of 2-hydroperoxycoelenterazine, generating protein-bound coelenteramide in an excited state. Here, the crystal structures of the Y138F obelin mutant before and after bioluminescence are reported at 1.72 and 1.30 Å resolution, respectively. The comparison of the spatial structures of the conformational states of Y138F obelin with those of wild-type obelin gives clear evidence that the substitution of Tyr by Phe does not affect the overall structure of both Y138F obelin and its product following Ca(2+) discharge compared with the corresponding conformational states of wild-type obelin. Despite the similarity of the overall structures and internal cavities of Y138F and wild-type obelins, there is a substantial difference: in the cavity of Y138F obelin a water molecule corresponding to W2 in wild-type obelin is not found. However, in Ca(2+)-discharged Y138F obelin this water molecule now appears in the same location. This finding, together with the observed much slower kinetics of Y138F obelin, clearly supports the hypothesis that the function of a water molecule in this location is to catalyze the 2-hydroperoxycoelenterazine decarboxylation reaction by protonation of a dioxetanone anion before its decomposition into the excited-state product. Although obelin differs from other hydromedusan Ca(2+)-regulated photoproteins in some of its properties, they are believed to share a common mechanism.

  1. High Iron Containing Sphalerite Concentrate by Catalytic Oxidation under High Pressure Oxygen and Ammonia Water Leaching%高铁闪锌矿精矿高氧催化氧化氨浸工艺试验

    Institute of Scientific and Technical Information of China (English)

    王书民; 樊雪梅; 张国春; 郑行望

    2011-01-01

    The optimal condition for the ammonia catalytic oxidation of the high iron containing sphalerite with high pressure oxygen is investigated by orthogonal experiment using table of L25(56). The results show that the leaching rates of zinc, copper, cadmium from the high iron containing sphalerite are up 93% , 94% and 91% , respectively, by salvolatile-ammonia water-perhydrol-catalyst system under the condition of 25℃ , 600kPa oxygen partial pressure, 7. 0 L/S ratio, leaching time 8h, and there is no iron in solution.%采用L25( 56)正交设计表,研究高铁闪锌矿精矿高氧催化氧化氨浸工艺的最佳工艺条件.结果表明,在25℃、氧分压为600kPa、液固比为7.0条件下,以碳铵-氨水-双氧水-催化剂体系氧化浸出高铁闪锌矿精矿8h,锌、铜、镉的浸出率分别可以达到93%,94%,91%,浸取液中不含铁.

  2. Enhanced bromate formation during chlorination of bromide-containing waters in the presence of CuO: Catalytic disproportionation of hypobromous acid

    KAUST Repository

    Liu, Chao

    2012-10-16

    Bromate (BrO3 -) in drinking water is traditionally seen as an ozonation byproduct from the oxidation of bromide (Br-), and its formation during chlorination is usually not significant. This study shows enhanced bromate formation during chlorination of bromide-containing waters in the presence of cupric oxide (CuO). CuO was effective to catalyze hypochlorous acid (HOCl) or hypobromous acid (HOBr) decay (e.g., at least 104 times enhancement for HOBr at pH 8.6 by 0.2 g L-1 CuO). Significant halate concentrations were formed from a CuO-catalyzed hypohalite disproportionation pathway. For example, the chlorate concentration was 2.7 ± 0.2 μM (225.5 ± 16.7 μg L-1) after 90 min for HOCl (Co = 37 μM, 2.6 mg L-1 Cl2) in the presence of 0.2 g L-1 CuO at pH 7.6, and the bromate concentration was 6.6 ± 0.5 μM (844.8 ± 64 μg L -1) after 180 min for HOBr (Co = 35 μM) in the presence of 0.2 g L-1 CuO at pH 8.6. The maximum halate formation was at pHs 7.6 and 8.6 for HOCl or HOBr, respectively, which are close to their corresponding pKa values. In a HOCl-Br--CuO system, BrO3 - formation increases with increasing CuO doses and initial HOCl and Br- concentrations. A molar conversion (Br - to BrO3 -) of up to (90 ± 1)% could be achieved in the HOCl-Br--CuO system because of recycling of Br - to HOBr by HOCl, whereas the maximum BrO3 - yield in HOBr-CuO is only 26%. Bromate formation is initiated by the formation of a complex between CuO and HOBr/OBr-, which then reacts with HOBr to generate bromite. Bromite is further oxidized to BrO3 - by a second CuO-catalyzed process. These novel findings may have implications for bromate formation during chlorination of bromide-containing drinking waters in copper pipes. © 2012 American Chemical Society.

  3. Water-soluble (?6-arene)ruthenium(II)-phosphine complexes and their catalytic activity in the hydrogenation of bicarbonate in aqueous solution

    OpenAIRE

    Horváth, Henrietta; Laurenczy, Gábor; Kathó, Ágnes; Horváth H. Henrietta (1979-) (vegyész); Kathó Ágnes (1954-) (vegyész, kémikus)

    2004-01-01

    The reactions of [(g6-C6H6)RuCl2]2 and [(g6-p-cymene)RuCl2]2 with hydrogen in the presence of the water-soluble phosphinestppts (meta-trisulfonated triphenylphosphine) and pta (1,3,5-triaza-7-phosphaadamantane) afforded as the main species [(g6-C6H6)RuH(tppts)2], [(g6-C6H6)RuH(pta)2], [(g6-p-cymene)RuH(tppts)2] and [(g6-p-cymene)RuH(pta)2]. This latter complexwas also formed in the reaction of [(g6-p-cymene)RuCl2(pta)] and hydrogen with a redistribution of pta. In addition, prolongedhydrogena...

  4. Hydrogen production from co-gasification of coal and biomass in supercritical water by continuous flow thermal-catalytic reaction system

    Institute of Scientific and Technical Information of China (English)

    YAN Qiuhui; GUO Liejin; LIANG Xing; ZHANG Ximin

    2007-01-01

    Hydrogen is a clean energy carrier.Converting abundant coal sources and green biomass energy into hydrogen effectively and without any pollution promotes environmental protection.The co-gasification performance of coal and a model compound of biomass,carboxymethylcellulose (CMC)in supercritical water (SCW),were investigated experimentally.The influences of temperature,pressure and concentration on hydrogen production from co-gasification of coal and CMC in SCW under the given conditions (20-25 MPa,650℃,15-30 s) are discussed in detail.The experimental results show that H2,CO2 and CH4 are the main gas products,and the molar fraction of hydrogen reaches in excess of 60%.The higher pressure and higher CMC content facilitate hydrogen production;production is decreased remarkably given a longer residence time.

  5. Treatment of reverse osmosis concentrated water by ClO2 three-phase catalytic oxidation%二氧化氯三相催化氧化法处理反渗透浓水试验研究

    Institute of Scientific and Technical Information of China (English)

    李常青; 杨岳; 刘发强; 刘光利; 江岩; 巫树峰

    2011-01-01

    In view of the fact that the reverse osmosis concentrated water from wastewater reuse device of Petrochemical Corporation is hard to be biodegraded for its high CODcr. And salt concentration, C1O2 three-phase catalytic oxidation process was used to treat the said kind of wastewater. The results of the test showed that: with the aid of catalyst under the condition that the optimal active components of the catalyst was CuO/NiO/La2O3/ CeO2, the optimal mole ratio of these metal oxides was 3 : 1 : 2 : 2; when the input flow of the reverse osmosis concentrated water was 50 L/h, the mass concentration of CODcr was 95 - 230 mg/L, the optimal pH value was 6.0 - 7.0, the C1O2 dosage was 90 - 120 mg/L, the air input was 0.6 - 0.9 mVh, the reaction time was 30 min, the removal rate of CODcr. Reached above 85%, the treated reverse osmosis concentrated water quality was stable and could meet the discharge standard. Thus it could draw a conclusion that, C1O2 three-phase catalytic oxidation is a feasible and competitive technology for reverse osmosis concentrated water treatment.%针对炼化企业污水回用装置反渗透单元浓水CODCr浓度高、难生化降解以及含盐量高等特点,利用ClO2三相催化氧化法处理反渗透浓水.试验结果表明:在催化剂存在条件下,催化剂的最佳活性组成为CuO/NiO/La2O3/CeO2,活性组分的最佳物质的量之比为3∶1∶2∶2;在反渗透浓水进水量为50 L/h、进水CODCr的质量浓度为95 ~ 230 mg/L时,最佳反应pH值为6.0~7.0,ClO2投加量为90~120 mg/L,空气进气量为0.6 ~ 0.9 m3/h,反应时间为30 min,CODCr去除率大于85%,处理后的反渗透浓水可以实现稳定达标排放.C1O2三相催化氧化处理反渗透浓水是一项具有良好实用性和很强竞争力的处理方法.

  6. Catalytic Polymer Multilayer Shell Motors for Separation of Organics.

    Science.gov (United States)

    Lin, Zhihua; Wu, Zhiguang; Lin, Xiankun; He, Qiang

    2016-01-26

    A catalytic polymer multilayer shell motor has been developed, which effects fast motion-based separation of charged organics in water. The shell motors are fabricated by sputtering platinum onto the exposed surface of silica templates embedded in Parafilm, followed by layer-by-layer assembly of polyelectrolyte multilayers to the templates. The catalytic shell motors display high bubble propulsion with speeds of up to 260 μm s(-1) (13 body lengths per second). Moreover, the polyelectrolyte multilayers assembled at high pH (pH>9.0) adsorb approximately 89% of dye molecules from water, owing to the electrostatic interaction between the positively charged polymers and the anionic dye molecules, and subsequently release them at neutral pH in a microfluidic device. The efficient propulsion coupled with the effective adsorption behavior of the catalytic shell motors in a microfluidic device results in accelerated separation of organics in water and thus holds considerable promise for water analysis.

  7. Detection of protozoans Babesia microti and [i]Toxoplasma gondii[/i] and their co-existence in ticks (Acari: Ixodida collected in Tarnogórski district (Upper Silesia, Poland

    Directory of Open Access Journals (Sweden)

    Marek Asman

    2015-02-01

    Full Text Available [b]Introduction[/b]. Ticks (Acari: Ixodida are vectors of many pathogens i. a: [i]Babesia microti [/i][Bm] and [i]Toxoplasma gondii[/i] [Tg]. In Poland, Ixodes ricinus [Ir] is the main vector of both pathogens. This tick species and pathogens transmitted by them are a significant threat to human and animal health. objectives of the study. Detection of the protozoans Bm and Tg in ticks collected in the Tarnogórski district area. [b]Material and methods[/b]. The ticks were collected from vegetation and pets in the spring period of their activity on the territory of the Tarnogórski district. The parasites were preserved in 70% ethanol. DNA was isolated by ammonia method. Bm was detected by nested-PCR using specific primers for the 18S rRNA sequence. To detect the Tg a commercial kit was used. The PCR products were separated on 2% ethidium bromide stained agarose gels and visualised under UV light. [b]Results[/b]. It was showed that all collected ticks belonged to the species Ir. Bm was detected in 50.87% and Tg in 64.91% of all examined ticks. Co-existence of these both protozoans in 36.84% of total examined ticks was noted. [b]Conclusions[/b]. The study showed a high risk of exposure to Bm and Tg in the studied area. Ticks Ir play an important role in the transmission of Bm in this region. Demonstrating a high percentage of ticks collected from animals infected with Tg may indicate their important role in the transmission of this pathogen, but it requires a further studies.

  8. Preparation and High-Temperature Water-Gas Shift Catalytic Features of La1-xCexFeO3 Perovskite

    Institute of Scientific and Technical Information of China (English)

    马红钦; 朱慧铭; 谭欣; 张继炎; 张鎏

    2004-01-01

    Based on water-gas shift reaction mechanism and perovskite compounds characteristics, La1-xCexFeO3 (.K) perovskite were designed and prepared as shift catalysts. DTA and XRD results reveal that La1-xCexFeO3 can be formed at 730~760 ℃ by mechanic-mix thermal decomposition method. Activity and heat-resisting tests show that La1-xCexFeO3 (.K) possess high thermal stability if x is less than or equals to 0.5. But when x is greater than 0.5, La1-xCexFeO3 (.K) will be converted into ceria and magnetite partially or completely under shift reaction conditions. In the case of x=0.5, the conversion of CO is about 68% at 530 ℃. Potassium can greatly improve the low temperature activity, but slightly reduces the high temperature activity, and has little impact on the thermal stability. La0.5Ce0.5FeO3 (.K) is a promising chromium-free high temperature shift catalyst.

  9. Numerical Study of Passive Catalytic Recombiner for Hydrogen Mitigation

    Directory of Open Access Journals (Sweden)

    Pavan K Sharma

    2010-10-01

    Full Text Available A significant amount of hydrogen is expected to be released within the containment of a water cooled power reactor after a severe accident. To reduce the risk of deflagration/detonation various means for hydrogen control have been adopted all over the world. Passive catalytic recombiner with vertical flat catalytic plate is one of such hydrogen mitigating device. Passive catalytic recombiners are designed for the removal of hydrogen generated in order to limit the impact of possible hydrogen combustion. Inside a passive catalytic recombiner, numerous thin steel sheets coated with catalyst material are vertically arranged at the bottom opening of a sheet metal housing forming parallel flow channels for the surrounding gas atmosphere. Already below conventional flammability limits, hydrogen and oxygen react exothermally on the catalytic surfaces forming harmless steam. Detailed numerical simulations and experiments are required for an in-depth knowledge of such plate type catalytic recombiners. Specific finite volume based in-house CFD code has been developed to model and analyse the working of these recombiner. The code has been used to simulate the recombiner device used in the Gx-test series of Battelle-Model Containment (B-MC experiments. The present paper briefly describes the working principle of such passive catalytic recombiner and salient feature of the CFD model developed at Bhabha Atomic Research Centre (BARC. Finally results of the calculations and comparison with existing data are discussed.

  10. Conformational Transition of Threonine Molecules and Catalytic Mechanism of Water Molecules and Hydroxyl Radicals%苏氨酸分子的构象转变及水分子与羟基自由基的催化机理

    Institute of Scientific and Technical Information of China (English)

    闫红彦; 王佐成; 佟华; 李鑫峡; 张丹; 孙双双

    2016-01-01

    采用密度泛函理论的 B3LYP 方法和微扰论的 MP2方法,研究苏氨酸分子构象转变机制以及水分子与羟基自由基对氢迁移反应的催化作用.结果表明:S-苏氨酸向R-别苏氨酸的构象转变反应有4个通道,R-别苏氨酸向R-苏氨酸与 S-苏氨酸向 S-别苏氨酸的构象转变反应各有1个通道;S-苏氨酸向R-别苏氨酸构象转变反应的最高能垒为250.2 kJ/mol;R-别苏氨酸向 R-苏氨酸构象转变反应的最高能垒为335.0 kJ/mol;S-苏氨酸向 S-别苏氨酸构象转变反应的最高能垒为359.6 kJ/mol;2个水分子构成的链及水分子/羟基自由基构成的链对质子迁移反应有较好的催化作用,使 S-苏氨酸向 R-别苏氨酸构象转变反应的高能垒分别降为128.3 kJ/mol 和108.6 kJ/mol.%Using B3LYP methods of density functional theory and the MP2 methods of perturbation theory,we studied conformational transition mechanism of threonine molecules and catalytic action of water molecules and hydroxyl radicals in the hydrogen transfer reaction.The results show that there are four channels in the conformational transition reaction of S-Thr to R-allo-Thr.There is one channel in the conformational transitions of R-allo-Thr to R-Thr and S-Thr to S-allo-Thr.The highest energy barriers for the conformational transition of S-Thr to R-allo-Thr,R-allo-Thr to R-Thr and S-Thr to S-allo-Thr are 250.2,335.0,359.6 kJ/mol.Besides,the chain composed of two water molecules and the chain composed of hydroxyl radical and water molecules have a better catalytic effect in proton migration reaction,and the high-energy barriers are reduced to 128.3,108.6 kJ/mol for the conformational transition of S-Thr to R-allo-Thr respectively.

  11. HYDROGEN TRANSFER IN CATALYTIC CRACKING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hydrogen transfer is an important secondary reaction of catalytic cracking reactions, which affects product yield distribution and product quality. It is an exothermic reaction with low activation energy around 43.3 kJ/mol. Catalyst properties and operation parameters in catalytic cracking greatly influence the hydrogen transfer reaction. Satisfactory results are expected through careful selection of proper catalysts and operation conditions.

  12. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  13. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  14. A new monetary phenomenon: An analysis of the co-existence of the external appreciation and the domestic inflation of RMB%试析人民币对外升值与对内贬值并存

    Institute of Scientific and Technical Information of China (English)

    贝多广; 朱晓莉

    2008-01-01

    Since 2002,RMB has shown a phenomenon which is the co-existence of the external appreciation and the domestic inflation.This new monetary phenomenon has been strengthened in the context that US dollar depreciates internationally and that domestic economy is overwhelmed with excessive liquidities.The new monetary phenomenon is the reflection of the real economy that continuing trade surplus,triggered robustly by the export-driven economy,which brings a huge amount of foreign exchange reserve and accelerates sequentially the expansion of domestic money supply.Furthermore,a refrained appreciation of RMB tends to deteriorate the domestic inflation,which is not simply a traditional concept of CPI but a broad inflation parameter including a variety of asset prices.It is sure that the new phenomenon is becoming a new challenge to the macroeconomic equilibrium as well as the decision maker of monetary policy.%2002年以来,人民币出现了对外升值和对内贬值并存的现象.在国际美元贬值和国内流动性过剩的背景下,这一货币现象得到了强化.这一货币现象是实际经济运行的反映:中国的出口导向型经济强势增长,国际收支持续顺差带来巨额外汇储备,进而推动国内货币供应量的扩张.当汇率和资本流动都受到管制时,压抑的对外升值趋势会成为对内贬值的直接原因.而对内贬值的概念已不是传统意义上的CPI上涨,而是包括资产价格膨胀在内的广义通货膨胀.这对于宏观经济平衡和货币政策制定者来说,都是一场新的挑战.

  15. Hydrophobic catalysts for liquid phase catalytic exchange: a review of preparation methods and influencing factors of catalytic activities

    International Nuclear Information System (INIS)

    Liquid phase catalytic exchange (LPCE) between liquid water and gaseous hydro- gen has been developed for various applications, such as tritium recovery, water upgrade and heavy-water production. Good wetproofing properties of the hydrophobic catalysts can make the reaction to proceed smoothly. In this article, the preparation methods of the hydrophobic catalysts and the factors affecting the catalytic activities are reviewed. In particular, progress on the hydrophobic Pt/C/inert carrier catalysts is introduced, including the selection of inert carrier and active metal carrier, and the preparation methods of carbon- supported Pt based catalysts. Basic research activities on controllable fabrication of hydro- phobic catalysts are discussed, including the LPCE reaction mechanism, and the relation between the microstructure of active metal and the catalytic activity, etc. Finally, questions remaining to be answered and future directions in the field of hydrophobic catalysts are discussed. (authors)

  16. Unsteady catalytic processes and sorption-catalytic technologies

    International Nuclear Information System (INIS)

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  17. Unsteady catalytic processes and sorption-catalytic technologies

    Energy Technology Data Exchange (ETDEWEB)

    Zagoruiko, A N [G.K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-07-31

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  18. Catalytic pyrolysis of olive mill wastewater sludge

    Science.gov (United States)

    Abdellaoui, Hamza

    From 2008 to 2013, an average of 2,821.4 kilotons/year of olive oil were produced around the world. The waste product of the olive mill industry consists of solid residue (pomace) and wastewater (OMW). Annually, around 30 million m3 of OMW are produced in the Mediterranean area, 700,000 m3 year?1 in Tunisia alone. OMW is an aqueous effluent characterized by an offensive smell and high organic matter content, including high molecular weight phenolic compounds and long-chain fatty acids. These compounds are highly toxic to micro-organisms and plants, which makes the OMW a serious threat to the environment if not managed properly. The OMW is disposed of in open air evaporation ponds. After evaporation of most of the water, OMWS is left in the bottom of the ponds. In this thesis, the effort has been made to evaluate the catalytic pyrolysis process as a technology to valorize the OMWS. The first section of this research showed that 41.12 wt. % of the OMWS is mostly lipids, which are a good source of energy. The second section proved that catalytic pyrolysis of the OMWS over red mud and HZSM-5 can produce green diesel, and 450 °C is the optimal reaction temperature to maximize the organic yields. The last section revealed that the HSF was behind the good fuel-like properties of the OMWS catalytic oils, whereas the SR hindered the bio-oil yields and quality.

  19. Highly sensitive catalytic spectrophotometric determination of ruthenium

    Science.gov (United States)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  20. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  1. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  2. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  3. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    Science.gov (United States)

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone.

  4. Catalytic Pyrolysis of Olive Mill Wastewater Sludge

    OpenAIRE

    Abdellaoui, Hamza

    2015-01-01

    Olive mill wastewater sludge (OMWS) is the solid residue that remains in the evaporation ponds after evaporation of the majority of water in the olive mill wastewater (OMW). OMWS is a major environmental pollutant in the olive oil producing regions. Approximately 41.16 wt. % of the OMWS was soluble in hexanes (HSF). The fatty acids in this fraction consist mainly of oleic and palmitic acid. Catalytic pyrolysis of the OMWS over red mud and HZSM-5 has been demonstrated to be an effective techno...

  5. Catalytic performance of Fe3O4-CoO/Al2O3 catalyst in ozonation of 2-(2,4-dichlorophenoxy) propionic acid,nitrobenzene and oxalic acid in water

    Institute of Scientific and Technical Information of China (English)

    Shaoping Tong; Rui Shi; Hua Zhang; Chunan Ma

    2010-01-01

    the precursors,and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP),nitrobenzene and oxalic acid.The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant,and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism.The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance.In the catalytic ozonation of 2,4-DP,the apparent reaction rate constants (k) were determined to be 1.456×10-2 min-1 for ozonation alone and 4.740×10-2 min-1 for O3/Fe3O4-CoO/Al2O3.And O3/Fe3O4-CoO/Al2O3 had a larger Rct (6.614×10-9) calculated by the relative method than O3 did (1.800×10-9),showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical.Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid.The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.

  6. Changes of Serotonin (5-HT), 5-HT2A Receptor, and 5-HT Transporter in the Sprague-Dawley Rats of Depression,Myocardial Infarction and Myocardial Infarction Co-exist with Depression

    Institute of Scientific and Technical Information of China (English)

    Mei-Yan Liu; Yah-Ping Ren; Wan-Lin Wei; Guo-Xiang Tian; Guo Li

    2015-01-01

    Background:To evaluate whether serotonin (5-HT),5-HT2A receptor (5-HT2AR),and 5-HT transporter (serotonin transporter [SERT]) are associated with different disease states of depression,myocardial infarction (MI) and MI co-exist with depression in Sprague-Dawley rats.Methods:After established the animal model of four groups include control,depression,MI and MI with depression,we measured 5-HT,5-HT2AR and SERT from serum and platelet lysate.Results:The serum concentration of 5-HT in depression rats decreased significantly compared with the control group (303.25 ± 9.99 vs.352.98 ± 13.73;P =0.000),while that in MI group increased (381.78 ± 14.17 vs.352.98 ± 13.73;P =0.000).However,the depression + MI group had no change compared with control group (360.62 ± 11.40 vs.352.98 ± 13.73;P =0.036).The changes of the platelet concentration of 5-HT in the depression,MI,and depression + MI group were different from that of serum.The levels of 5-HT in above three groups were lower than that in the control group (380.40 ± 17.90,387.75 ± 22.28,246.40 ± 18.99 vs.500.29 ± 20.91;P =0.000).The platelet lysate concentration of 5-HT2AR increased in depression group,MI group,and depression + MI group compared with the control group (370.75 ± 14.75,393.47 ± 15.73,446.66 ± 18.86 vs.273.66 ± 16.90;P =0.000).The serum and platelet concentration of SERT in the depression group,MI group and depression + MI group were all increased compared with the control group (527.51 ± 28.32,602.02 ± 23.32,734.76 ± 29.59 vs.490.56 ± 16.90;P =0.047,P =0.000,P =0.000 in each and 906.38 ± 51.84,897.33 ± 60.34,1030.17 ± 58.73 vs.708.62 ± 51.15;P =0.000 in each).Conclusions:The concentration of 5-HT2AR in platelet lysate and SERT in serum and platelet may be involved in the pathway of MI with depression.Further studies should examine whether elevated 5-HT2AR and SERT may contribute to the biomarker in MI patients with depression.

  7. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brownian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d=3.

  8. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    洪文明; 王梓坤

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brown-ian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d = 3.

  9. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  10. Catalytic Kinetic Determination of Bicarbonate and Carbonate in Leather Water by FIA%FIA-催化动力学法在线测定制革用水HCO3-和CO32-

    Institute of Scientific and Technical Information of China (English)

    俞凌云; 尚永昌; 安胜波; 卢艳青; 张新申

    2011-01-01

    A flow injection catalytic kinetic spectrophotometic method was developed for the rapid determination of bicarbonate and carbonate in water. The chromogenic reaction of trivalent chromium and xylenol orange is catalysed by bicarbonate and carbonate under heating condition. The optimum analysis conditions are as follows: detection wavelength is 550nm, temperature is 75 ℃;the length of the reaction coil is 3.9m; the volume of the sampling loop is 250μL; the concentration of chromogenic reagent R1 ( xylenol orange) is 0.004g/L and the concentration of chromogenic reagent R2 ( Chromium Nitrate) is 0.04mol/L. When the concentration of bicarbonate and carbonate was between 10mg/L and 220mg/L, the peak height was proportional was to the content of bicarbonate; the linear correlation coefficient is 0. 998 7; the relative standard deviation is 0. 609% measuring 10 times repeatedly. And the method is used to determine the content of bicarbonate in several samples, and it shows its good reproducibility and accuracy, with the recoveries of standard addition between 97.88% and 99.47%.%根据三价铬与二甲酚橙在碳酸氢根或碳酸根的催化作用下发生的显色反应,建立了流动注射催化动力学分光光度法,对水中的碳酸氢根和碳酸根浓度进行了检测.通过对各种影响因素进行优化,确定最佳分析条件为:波长550nm,温度75℃,反应圈3.9m,进样环体积250μL,R1显色液二甲酚橙的浓度为0.004g/L,R2显色液硝酸铬的浓度为0.04mol/L.HCO3-和CO32-含量在10~220mg/L范围内峰高与浓度成正比,线性相关系数为R2=0.9987,精密度RSD=0.609%(n=10).用该法检测实际水样中的碳酸氢根时,加标回收率为97.88%~99.47%,具有良好的重现性和准确性.

  11. Preparation of Pt-Ru hydrophobic catalysts and catalytic activities for liquid phase catalytic exchange reaction

    International Nuclear Information System (INIS)

    Pt/C and Pt-Ru/C catalysts with different ratios of Pt to Ru were synthesized, using ethylene glycol as both the dispersant and reducing agent at 1-2 MPa by microwave-assisted method. The catalysts were characterized by XRD, TEM and XPS. The mean particle sizes of the Pt/C and Pt-Ru/C catalysts were 1.9-2.0 nm. Pt and Ru existed as Pt(0), Pt(II), Pt(IV), Ru(0) and Ru(IV) for Pt-Ru/C catalysts, respectively. The face-centered cubic structure of the active mental particles would be changed upon the addition of Ru gradually. Then polytetrafluoroethylene and carbon-supported Pt and Pt-Ru catalysts were supported on foamed nickel to obtain hydrophobic catalysts. The catalytic activity was increased for liquid phase catalytic exchange (LPCE) when uniform Pt based hydrophobic catalysts was mixed into appropriate Ru. Hydrogen isotope exchange reaction occurs between hydration layer(H2O)nH+(ads)(n≥2) and D atoms due to intact water molecules being on Pt surface for LPCE. Water molecules have a tendency to dissociate to OH(ads) and H(ads) on metal Ru surface, and there is the other reaction path for Pt-Ru binary catalysts, which is probably the main reason of the increase of the catalytic activity of the hydrophobic Pt-Ru catalyst. (authors)

  12. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; ZHANG Yan; LIU Hong-yuan

    2003-01-01

    The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4% to 89.4%.

  13. Post-treatment of refinery wastewater effluent using a combination of AOPs (H2O2 photolysis and catalytic wet peroxide oxidation) for possible water reuse. Comparison of low and medium pressure lamp performance.

    Science.gov (United States)

    Rueda-Márquez, J J; Levchuk, I; Salcedo, I; Acevedo-Merino, A; Manzano, M A

    2016-03-15

    The main aim of this work was to study the feasibility of multi-barrier treatment (MBT) consisting of filtration, hydrogen peroxide photolysis (H2O2/UVC) and catalytic wet peroxide oxidation (CWPO) for post-treatment of petroleum refinery effluent. Also the possibility of water reuse or safe discharge was considered. The performance of MBT using medium (MP) and low (LP) pressure lamps was compared as well as operation and maintenance (O&M) cost. Decomposition of organic compounds was followed by means of gas chromatography-mass spectrometry (GC-MS), total organic carbon (TOC) and chemical oxygen demand (COD) analysis. After filtration step (25 μm) turbidity and concentration of suspended solids decreased by 92% and 80%, respectively. During H2O2/UVC process with LP lamp at optimal conditions (H2O2:TOC ratio 8 and UVC dose received by water 5.28 WUVC s cm(-2)) removal of phenolic compounds, TOC and COD was 100%, 52.3% and 84.3%, respectively. Complete elimination of phenolic compounds, 47.6% of TOC and 91% of COD was achieved during H2O2/UVC process with MP lamp at optimal conditions (H2O2:TOC ratio 5, UVC dose received by water 6.57 WUVC s cm(-2)). In order to compare performance of H2O2/UVC treatment with different experimental set up, the UVC dose required for removal of mg L(-1) of COD was suggested as a parameter and successfully applied. The hydrophilicity of H2O2/UVC effluent significantly increased which in turn enhanced the oxidation of organic compounds during CWPO step. After H2O2/UVC treatment with LP and MP lamps residual H2O2 concentration was 160 mg L(-1) and 96.5 mg L(-1), respectively. Remaining H2O2 was fully consumed during subsequent CWPO step (6 and 3.5 min of contact time for LP and MP, respectively). Total TOC and COD removal after MBT was 94.7% and 92.2% (using LP lamp) and 89.6% and 95%, (using MP lamp), respectively. The O&M cost for MBT with LP lamp was estimated to be 0.44 € m(-3) while with MP lamp it was nearly five

  14. 油包水微乳液中抗体酶催化布洛芬酯选择性水解的酶学特性%Enzymological Characteristics of Catalytic Antibody-catalyzed enantioselective Hydrolysis of Ibuprofen Ester in Water-in-oil microemulsion

    Institute of Scientific and Technical Information of China (English)

    杨根生; 戚映丹; 欧志敏; 姚善泾

    2009-01-01

    The asymmetric hydrolyzation of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. A catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was successfully elicited against an immunogen consisting of tetrahedral sulfate hapten attached to bovine serum albumin (BSA). The rate constant enhancement factor Kcat/Kuncat was about 1.6x104. The catalytic activity of the catalytic antibody in a reverse micelle reaction system based on sodium b/s (2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane was studied. Kinetic analysis of the catalytic antibody-catalyzed reaction was found to be possible in this system. Kinetic studies showed that hydrolysis in the microemulsion system follow Michaelis-Menten kinetics. The catalytic antibody can also accelerate catalysis of S-ibuprofen methyl ester in the microemulsion system. Temperature effects, the pH profile, Km,app and Kcat were determined. The dependence of the catalytic antibody hydrolytic activity on the Wo (molar ratio of water to surfactant) showed a bell-shaped curve, presenting a maximum at about wo = 21.%根据过渡态理论设计和合成了能诱导产生催化选择性水解布洛芬甲酯的催化抗体的四面体硫酸盐半抗原,并与牛血清白蛋白(BSA)偶联制备成免疫源,通过免疫手段成功筛选出具有加速选择性水解生成S-布洛芬的特异性催化抗体.其Kcat,app/Kuncat,app达1.6x104.进一步地将催化抗体运用到W/O微乳体系(反胶束)中进行布洛芬酯的选择性水解研究,其动力学研究证明其催化过程同样遵循Michaelis.Menten方程.考察了pH值和温度对催化初速度影响,Wo(体系中水和琥珀酸二辛酯磺酸钠(AOT)的摩尔比)对催化初速度影响呈现为钟罩型,最适的Wo.为21.

  15. Clay Minerals as Solid Acids and Their Catalytic Properties.

    Science.gov (United States)

    Helsen, J.

    1982-01-01

    Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

  16. The tritium labelling of butibufen by herterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    The labelling of a new non-steroidal antiinflammatory agent, butibufen (2-(4-isobutylphenyl) butyric acid) was studied. The method used was heterogeneous catalytic exchange between butibufen and tritiated water, obtained ''in situ''. Purification was accomplished through thin layer chromatography. Concentration, purity and specific activity of the labeled drug were determined by ultraviolet and liquid scintillation techniques. (author)

  17. The tritium labeling of Butibufen by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    The labeling of a new non-steroidal antiinflammatory agent, Butibufen (2-(4-isobutylphenyl) butyric acid) was studied. The method used was heterogeneous catalytic exchange between Butibufen and tritiated water, obtained in situ. Purification was accomplished through thin layer chromatography. Concentration, purity and specific activity of the labeled drug were determined by ultraviolet and liquid scintillation techniques. (Author) 7 refs

  18. 多重抗神经元抗体阳性的自身免疫性脑炎临床分析%Clinical analysis of autoimmune encephalitis with co-existence of multiple anti-neuronal antibodies

    Institute of Scientific and Technical Information of China (English)

    任海涛; 杨洵哲; 关鸿志; 高鑫雅; 彭斌; 朱以诚; 崔丽英

    2016-01-01

    antibodies to neuronal cell-surface or synaptic receptors (including N-methyl-D-aspartate receptor (NMDAR),contactin-associated protein-like 2 (CASPR2),α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR),leucine-rich glioma inactivated protein 1 (LGI1),and gamma-aminobutyric acid beta receptor (GABABR)).In those patients with positive antibodies,antibodies against intracellular neuronal antigens associated with paraneoplastic neurological symptoms were tested.Anti-aquaporin protein-4 (AQP4) antibody was tested depending on patients' clinical manifestations.Results Ten patients were detected combined with additional autoantibodies in 531 patients with positive antibodies related to autoimmune encephalitis.AntiHu antibody was positive in 5 patients with anti-GABABR encephalitis,in 1 of whom anti-NMDAR antibody was also identified;anti-AQP4 antibody was positive in 1 patient with relapsing anti-NMDAR encephalitis;anti-CASPR2 and anti-Yo antibodies were respectively positive in 2 patients with anti-LGI1 encephalitis;anti-CV2 and anti-Hu antibodies were respectively positive in 2 patients with anti-AMPAR encephalitis.Clinical presentation of all cases was consistent with typical encephalitis or limbic encephalitis.Brain stem was involved in 3 patients.Peripheral sensory neuropathy was present in 1 patient,while myalgia and fasciculation were present in 1 patient.Seven patients responded well to the immunotherapy.Tumors were pathologically or radiologically confirmed in 7 cases,including lung cancer in 5 cases,suspected thymoma in 1 case and highly suspected mediastinal tumor without pathological identification in 1 case.Conclusions Due to the pathological mechanism,co-existence of multiple autoantibodies affects clinical manifestations of patients and results in variation and overlap of them.The additional positivity of onconeuronal antibodies directs the search for occult tumor.

  19. A catalytic recombiner performance analysis considering fluid dynamics in a containment

    Energy Technology Data Exchange (ETDEWEB)

    Tahara, Mika; Oikawa, Hirohide [Toshiba Corporation, Plant and System Planning Department, Yokohama, Kanagawa (Japan); Arai, Kenji [Toshiba Corporation, Nuclear System Analysis Technology R and D Department, Kawasaki, Kanagawa (Japan)

    2000-10-01

    A severe accident in a light water reactor has the potential to generate hydrogen resulting from metal-water reaction and radiolysis of water. To prevent hydrogen combustion, a flammability gas control system is installed in a reactor containment. Recently passive catalytic recombiners have been developed for the flammability gas control. The catalytic recombiner has advantages over the current heated type recombiner for low costs, easy maintenance, robustness during an accident, and flexible layout. However the hydrogen depletion rate of the catalytic recombiner is affected by the local thermal hydraulic conditions during an accident. To evaluate hydrogen depletion by the catalytic recombiner considering the thermal hydraulic conditions in the containment, a 3-dimensional fluid dynamics analysis is useful. Then a catalytic recombiner model has been developed in which the flammable gas depletion rate is estimated accounting for the flammable gas transfer rate to the catalyst active point from bulk gas. And this model has been incorporated into a 3-dimensional fluid dynamic model, which has been developed using a CFD code STAR-CD. In this paper the 3-dimensional catalytic recombiner model was applied to a catalytic recombiner consisting of plate type catalyst. Confirmation of this model was conducted by using the test result of KALI-H2. The analysis model reasonably predicts the local thermal hydraulic conditions in the containment and the catalytic recombiner performance. (author)

  20. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  1. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne;

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  2. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  3. Catalytically and noncatalytically treated automobile exhaust: biological effects in rats

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, G.P. (Univ. of Cincinnati); Lewkowski, J.P.; Hastings, L.; Malanchuk, M.

    1977-12-01

    Chronic exposure to catalytically treated or noncatalytically treated automobile exhaust significantly depressed the spontaneous locomotor activity (SLA) of rats. Exposure to H/sub 2/SO/sub 4/ alone or CO at comparable levels did not alter the SLA. Exposure to noncatalytically treated exhaust resulted in significant reductions in growth rate and food and water intake. However, these effects were not evident in the exposure to catalytically treated exhaust or in the control H/sub 2/SO/sub 4/ and CO exposures. Blood acid-base analyses indicated that exposure to either catalytically treated exhaust or H/sub 2/SO/sub 4/ elicits a metabolic alkalosis, while exposure to CO alone results in a metabolic acidosis. All acid-base parameters were within the normal range several weeks after the termination of exposure.

  4. Production of furfural from xylose, water-insoluble hemicelluloses and water-soluble fraction of corncob via a tin-loaded montmorillonite solid acid catalyst.

    Science.gov (United States)

    Li, Huiling; Ren, Junli; Zhong, Linjie; Sun, Runcang; Liang, Lei

    2015-01-01

    The conversion of xylose, water-insoluble hemicelluloses (WIH) and water-soluble fraction (WSF) of corncob to furfural was performed using montmorillonite with tin ions (Sn-MMT) containing double acid sites as a solid acid catalyst. The co-existence of Lewis acids and Brønsted acids in Sn-MMT was shown to improve the furfural yield and selectivity. 76.79% furfural yield and 82.45% furfural selectivity were obtained from xylose using Sn-MMT as a catalyst in a biphasic system with 2-s-butylphenol (SBP) as the organic extracting layer and dimethyl sulfoxide (DMSO) as the co-solvent in contact with an aqueous phase saturated with NaCl (SBP/NaCl-DMSO) at 180°C for 30min. Furthermore, Sn-MMT also demonstrated the excellent catalytic performance in the conversion of pentose-rich materials of corncob and 39.56% and 54.15% furfural yields can be directly obtained from WIH and WSF in the SBP/NaCl-DMSO system, respectively.

  5. Fluid catalytic cracking of biomass pyrolysis vapors

    Energy Technology Data Exchange (ETDEWEB)

    Mante, Ofei Daku [Virginia Polytechnic Institute and State University, Biological Systems Engineering, Blacksburg, VA (United States); Agblevor, Foster A. [Utah State University, Biological Engineering, Logan, UT (United States); McClung, Ron [BASF Inc, Florham, NJ (United States)

    2011-12-15

    Catalytic cracking of pyrolysis oils/vapors offers the opportunity of producing bio-oils which can potentially be coprocessed with petroleum feedstocks in today's oil refinery to produce transportation fuel and chemicals. Catalyst properties and process conditions are critical in producing and maximizing desired product. In our studies, catalyst matrix (kaolin) and two commercial fluid catalytic cracking (FCC) catalysts, FCC-H and FCC-L, with different Y-zeolite contents were investigated. The catalytic cracking of hybrid poplar wood was conducted in a 50-mm bench-scale bubbling fluidized-bed pyrolysis reactor at 465 C with a weight hourly space velocity of 1.5 h{sup -1}. The results showed that the yields and quality of the bio-oils was a function of the Y-zeolite content of the catalyst. The char/coke yield was highest for the higher Y-zeolite catalyst. The organic liquid yields decreased inversely with increase in zeolite content of the catalyst whereas the water and gas yields increased. Analysis of the oils by both Fourier-transform infrared and {sup 13}C-nuclear magnetic resonance indicated that the catalyst with higher zeolite content (FCC-H) was efficient in the removal of compounds like levoglucosan, carboxylic acids and the conversion of methoxylated phenols to substituted phenols and benzenediols. The cracking of pyrolysis products by kaolin suggests that the activity of the FCC catalyst on biomass pyrolysis vapors can be attributed to both Y-zeolite and matrix. The FCC-H catalyst produced much more improved oil. The oil was low in oxygen (22.67 wt.%), high in energy (29.79 MJ/kg) and relatively stable over a 12-month storage period. (orig.)

  6. Fe/Cu催化还原降解饮用水中溴氯乙腈的性能研究%Performance Study of Bromochloracetonitrile Degradation in Drinking Water by Fe/Cu Catalytic Reduction

    Institute of Scientific and Technical Information of China (English)

    丁春生; 马海龙; 傅洋平; 赵世督; 李东兵

    2015-01-01

    为了降低饮用水在氯消毒过程中产生的消毒副产物(DBPs)溴氯乙腈(BCAN)对人体带来的健康危害,采用 Fe/ Cu 催化还原的方法降解饮用水中低浓度的 BCAN,考察了 BCAN 的降解效果和其影响因素,探讨了其降解机制及动力学规律.结果表明,Fe/ Cu 具有更强的还原降解 BCAN 的能力,与零价铁相比, Fe/ Cu(质量比为10:1)的降解效率是其1.5倍.随着 Fe/ Cu 投加量的增加,BCAN 的去除率有明显的提高,对于初始浓度为20μg•L -1的 BCAN 溶液,当 Fe/ Cu(质量比为10:1)投加量由5 g•L -1增加到10 g•L -1,反应150 min 后,去除率由51.1%增加到89.5%. BCAN 降解效率随着温度的升高逐渐提高,BCAN 初始浓度的变化对 Fe/ Cu 去除 BCAN 的去除效果影响不大,Fe/ Cu 降解 BCAN 符合一级反应动力学规律.%The paper used the method of iron copper catalyst reduction to degrade low concentrations of bromochloracetonitrile (BCAN) to lighten the damage to human being, which is a kind of disinfection by-products (DBPs) produced during the chlorination process of drinking water. The removal efficiency of BCAN and its influencing factors were investigated. The mechanism of degradation and kinetics were also explored. The results indicated that iron copper had a greater degradation ability towards BCAN, and the degradation rate of iron copper (mass ratio of 10: 1) was 1. 5 times that of the zero-valent iron. The removal of BCAN increased obviously with the increase of Fe/ Cu dosage. When the initial concentration was set at 20 μg•L - 1 , after a reaction time of 150 min, removal of BCAN was improved from 51. 1% to 89. 5% with the increase of iron copper (mass ratio of 10: 1) dosage from 5 g•L - 1 to 10 g•L - 1 . The temperature also had great impact on BCAN removal and the removal increased with the increase of temperature. However, BCAN removal did not change a lot with the variation of the initial concentration of BCAN when it was at

  7. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author)

  8. Simple, chemoselective, catalytic olefin isomerization.

    Science.gov (United States)

    Crossley, Steven W M; Barabé, Francis; Shenvi, Ryan A

    2014-12-01

    Catalytic amounts of Co(Sal(tBu,tBu))Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.

  9. Comparison of drought strategies of three co-existing woody plants by their hydraulic structures%从水力结构比较3种共存木本植物的抗旱策略

    Institute of Scientific and Technical Information of China (English)

    靳欣; 徐洁; 白坤栋; 冯锦霞; 张劲松; 万贤崇

    2011-01-01

    通过盆栽控水方法测定了华北石质山区刺槐、栓皮栎和侧柏3个主要造林树种在干旱胁迫以及随后的复水条件下气体交换和水分关系的变化,分析了这3个树种抗旱特性的差异。结果表明:1)在供水充足时,刺槐光合作用强、气孔导度大、耗水速度快。2)刺槐对土壤水分变化最为敏感,当土壤水分含量降低时,其光合速率和气孔导度迅速下降。3)复水后,刺槐和栓皮栎恢复速度比侧柏快。4)当小枝导水损失率发生变化时,刺槐的气孔导度变化迅速,相比之下,栓皮栎和侧柏对土壤水分变化以及其气孔导度随水力变化的反应都较为平缓。5)刺槐在水分充足时迅速进行光合积累,而干旱时,通过气孔关闭甚至落叶来避免过度失水。另外2种植物在中度干旱时,尤可保持光合作用,其中侧柏更为突出。在华北半干旱的石质山区,刺槐的发展受到较大限制。%This paper investigates the physiological characteristics for drought resistance among three main afforestation woody species(ie Robinia pseudoacacia L.,Quercus variabilis Blume,Platycladus orientalis(L.) Franco) in lithoid mountainous areas in north China.Variations in their gas exchanges and water relations were comparatively measured during withholding water and subsequent rewatering of potted seedlings.The results showed that:1) under well-watered conditions,black locust(R.pseudoacacia) had the strongest photosynthesis,the greatest stomatal conductance and water consumption among the three species.2) However,black locust was most sensitive to soil drying among the three species,its photosynthesis and stomatal conductance rapidly declined.3) On being rewatered,both gas exchanges and water relations were able to be rapidly recovered in all three species,among which black locust and cork oak(Q.variabilis) had faster recovery than arborvitae(P.orientalis).4) Stomatal

  10. Effect of ions in water on the catalytic ozonation by pumice supported zinc%水中常见离子对锌改性浮石催化臭氧化有机物效能的影响

    Institute of Scientific and Technical Information of China (English)

    袁磊; 杨帆; 倪红伟

    2015-01-01

    采用锌改性浮石为催化剂,催化臭氧氧化难降解的硝基类卤代芳香族有机化合物-对氯硝基苯,对水中常见无机离子对催化臭氧氧化去除水中微量对氯硝基苯的效能进行了比较。实验结果表明,水中阳离子Na+和 K+对去除效能影响较小,Ca2+和 Mg2+对去除效能略有促进作用。阴离子对去除效能影响较为明显,均有一定抑制作用,NO3-和Cl-影响不明显,其中以SO42-和PO43-的抑制影响最大。%The catalytic ozonation of p-chloronitrobenzene (p-CNB) in an aqueous solution using modification pumice as the catalysts was investigated. The effects of NO3-, Na+, and K+ on the catalytic ozonation of p-CNB can be ignored. Degradation effi-ciency was slightly promoted in the presence of Ca2+ and Mg2+. The ozonation of p-CNB was slightly inhibited by the high con-centration of Cl-. The removal efficiency of p-CNB decreased in the presence of SO42-, given that the hydroxyl inhibitors PO43- can significantly inhibit the catalytic degradation of p-CNB.

  11. Catalytic Polymer Multilayer Shell Motors for Separation of Organics.

    Science.gov (United States)

    Lin, Zhihua; Wu, Zhiguang; Lin, Xiankun; He, Qiang

    2016-01-26

    A catalytic polymer multilayer shell motor has been developed, which effects fast motion-based separation of charged organics in water. The shell motors are fabricated by sputtering platinum onto the exposed surface of silica templates embedded in Parafilm, followed by layer-by-layer assembly of polyelectrolyte multilayers to the templates. The catalytic shell motors display high bubble propulsion with speeds of up to 260 μm s(-1) (13 body lengths per second). Moreover, the polyelectrolyte multilayers assembled at high pH (pH>9.0) adsorb approximately 89% of dye molecules from water, owing to the electrostatic interaction between the positively charged polymers and the anionic dye molecules, and subsequently release them at neutral pH in a microfluidic device. The efficient propulsion coupled with the effective adsorption behavior of the catalytic shell motors in a microfluidic device results in accelerated separation of organics in water and thus holds considerable promise for water analysis. PMID:26632275

  12. Comparison between a Water-Based and a Solvent-Based Impregnation Method towards Dispersed CuO/SBA-15 Catalysts: Texture, Structure and Catalytic Performance in Automotive Exhaust Gas Abatement

    Directory of Open Access Journals (Sweden)

    Qi Xin

    2016-10-01

    Full Text Available Supported copper oxide nanoparticles are a potential candidate for replacing the rare and expensive precious metals within the automotive three-way catalyst. However, a well-designed dispersion method is necessary to allow a stable high loading of active material, compensating its lower intrinsic activity and stability. In this work, a CuO-loaded SBA-15 catalyst has been manufactured by two methods. The ammonia-driven deposition precipitation (ADP and the molecular designed dispersion (MDD methods are both considered as efficient deposition methods to provide well-dispersed copper oxide-based catalysts. Their morphology, copper dispersion and the chemical state of copper were characterized and compared. Due to the differences in the synthesis approach, a difference in the obtained copper oxide phases has been observed, leading to a distinct behavior in the catalytic performance. The structure-activity correlation of both catalysts has also been revealed for automotive exhaust gas abatement. Results demonstrate that various copper species can be formed depending on the precursor–support interaction, affecting selectivity and conversion during the catalytic reaction.

  13. Catalytic Fast Pyrolysis: A Review

    Directory of Open Access Journals (Sweden)

    Theodore Dickerson

    2013-01-01

    Full Text Available Catalytic pyrolysis is a promising thermochemical conversion route for lignocellulosic biomass that produces chemicals and fuels compatible with current, petrochemical infrastructure. Catalytic modifications to pyrolysis bio-oils are geared towards the elimination and substitution of oxygen and oxygen-containing functionalities in addition to increasing the hydrogen to carbon ratio of the final products. Recent progress has focused on both hydrodeoxygenation and hydrogenation of bio-oil using a variety of metal catalysts and the production of aromatics from bio-oil using cracking zeolites. Research is currently focused on developing multi-functional catalysts used in situ that benefit from the advantages of both hydrodeoxygenation and zeolite cracking. Development of robust, highly selective catalysts will help achieve the goal of producing drop-in fuels and petrochemical commodities from wood and other lignocellulosic biomass streams. The current paper will examine these developments by means of a review of existing literature.

  14. Combined catalytic converter and afterburner

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-30

    This patent describes the combined use of a catalytic converter and afterburner. An afterburner chamber and a catalyst matrix are disposed in series within a casing. A combustible premixed charge is ignited in the afterburner chamber before it enters the catalyst matrix. This invention overcomes the problem encountered in previous designs of some of the premixed charge passing unreacted through the device unless a very long afterburner chamber is used. (UK)

  15. Thermodynamics of catalytic nanoparticle morphology

    Science.gov (United States)

    Zwolak, Michael; Sharma, Renu; Lin, Pin Ann

    Metallic nanoparticles are an important class of industrial catalysts. The variability of their properties and the environment in which they act, from their chemical nature & surface modification to their dispersion and support, allows their performance to be optimized for many chemical processes useful in, e.g., energy applications and other areas. Their large surface area to volume ratio, as well as varying sizes and faceting, in particular, makes them an efficient source for catalytically active sites. These characteristics of nanoparticles - i.e., their morphology - can often display intriguing behavior as a catalytic process progresses. We develop a thermodynamic model of nanoparticle morphology, one that captures the competition of surface energy with other interactions, to predict structural changes during catalytic processes. Comparing the model to environmental transmission electron microscope images of nickel nanoparticles during carbon nanotube (and other product) growth demonstrates that nickel deformation in response to the nanotube growth is due to a favorable interaction with carbon. Moreover, this deformation is halted due to insufficient volume of the particles. We will discuss the factors that influence morphology and also how the model can be used to extract interaction strengths from experimental observations.

  16. Catalytic combustion in gas stoves - Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin [CATATOR AB, Lund (Sweden)

    2003-06-01

    . To overcome the latter, improved aeration of the system is needed, e.g. modification of nozzle-size and/or flame port plate. The effects of installing a retro-fit catalytic design onto the burner in the gas oven were also examined. Similar to the burners of the cooking plates, the emitted NO{sub x} was greatly reduced, i.e. up to 90 %. Other on-going projects using similar catalyst concepts as in this study have shown that the life-time of the catalyst, i.e. the mechanical stability and the catalytic activity, is extremely good (> 1000 h). To examine if this durability of the catalyst is limited in this specific application by deactivation caused by possible food spillage, a number of commonly used food ingredients were painted onto the catalysts and the activity of the catalyst prior to and after the 'deactivation' was investigated. The results show that no ingredients of organic type (fat, milk, egg, sugar) have any significant impact on the catalytic activity. Salt however was seen to block active reaction sites of the catalyst, but the tests showed that the catalyst could in this case be easily re-activated by simply washing it in water. The design modifications are very modest and the amount of catalyst is small, costing about 6-10 SEK (0.80-1.2 USD) per cooking plate.

  17. Catalytic Potential of Nano-Magnesium Oxide on Degradation of Humic Acids From Aquatic Solutions

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2014-12-01

    Full Text Available Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO for the removal of humic acids (HA from water. Mg (NO32 solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA and phosphate on HA degradation were evaluated. Experimental results indicated that degradation of HA was increased as the pH solution and reaction time were increased. Maximum HA degradation was obtained at pH = 10 and the reaction time of 10 minutes in the catalytic process. The calculated catalytic potential of nano-MgO on ozonation of HA was 60%. Moreover, catalytic ozonation process was not affected by TBA and the main reaction on HA degradation HA have effect take place on MgO surface. According to the results of this study, the developed MgO catalyst is the active and proficient catalyst in HA degradation using the catalytic ozonation process.

  18. Catalytic Partial Oxidation of Biomass/Oil Mixture

    OpenAIRE

    Veselý, V; Hanika, J. (Jiří); Tukač, V.; LEDERER, J.; Kovač, D.

    2013-01-01

    Investigation was focussed to application of waste POX (partial oxidation), e.g., meal rape in form of suspension in high boiling hydrocarbons from crude oil distillation. There is an opportunity for utilization of biomass waste resulted from fuels bio-components production. A decrease of oxygen and water steam demand in feed for POX process was observed in this variant. Catalytic effect of iron nanoparticles or nickel nitrate as catalysts in improvement of the pilot plant biomass/oil partial...

  19. The tritium labelling of ibuprofen by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    The tritium labelling of 2-(4-isobutylphenyl) propionic acid (ibuprofen) was performed. The method employed was heterogeneous catalytic exchange between ibuprofen and tritiated water. Prior to labelling, thermic stability of ibuprofen was studied. Purification was accomplished through thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Concentration, purity and specific activity of the labelled compound were determined by ultraviolet, HPLC and liquid scintillation techniques. (author)

  20. Flow Injection Determination of Oxalate Based on Its Catalytic Effect on the Oxidation of p-Chloride Aniline by Dichromate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In a sulfuric acid medium, oxalate exhibits a strong catalytic effect on the oxidation of p-chloride aniline (ClBN) by dichromate, and the red oxidation product of ClBN has a maximum absorbancy at 520 nm. Based on this founding, a new FI method for determining oxalate was developed. A calibration curve of oxalate in the range of 0. 40-17.0 tg/mL was obtained. The detection limit was 0. 10 μg/mL. Sampling rate was 103-samples/h. The possible interference by the co-existing substances or ions was examined. This new method was applied to the determination of micro amounts of oxalate in real samples with satisfactory results.

  1. Catalytic pyrolysis of Pubescens to phenols over Ni/C catalyst

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The pyrolysis of Pubescens over Ni/C catalyst was studied at 350°C in H2 flow.The presence of Ni/C catalyst efficiently improved the degradation of raw materials,and produced bio-oil with high content of phenols but low contents of acetic acid,furfural and water.In the reaction,Ni/C catalyst plays the role of catalytic decomposition and catalytic hydrogenation.The existence of the carbon carrier favors the formation of active Ni in small sizes with more defects,which results in high catalytic activity of Ni in biomass decomposition and selective production of phenols.

  2. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  3. Experimental research on removing cyanide and ammonia nitrogen from industrial waste water produced by gold smelting with electro-catalytic oxidation process%电催化氧化法去除黄金冶炼废水中氰化物和氨氮试验研究

    Institute of Scientific and Technical Information of China (English)

    方荣茂; 廖小山; 廖斌; 林烽先; 刘亚建

    2013-01-01

    Research started with treating industrial waste water produced by gold smelting with electro-catalytic oxidation process, during which the influences of chloride ion mass concentration, plate clearance and current density on the removal of cyanide and ammonia nitrogen were analyzed. The result shows the optimal conditions for removing cyanide and ammonia nitrogen with electro-catalytic oxidation process are like this; the initial pH of waste water 9. 28, initial chloride ion concentration 25 g/L, plate clearance 20 mm, current density 16.3 mA/cm2 , and waste water circulation velocity 64 mL/min. With the above conditions and electrolysis time 150 min,the cyanide concentration decreases from 28. 84 mg/L to 0. 20 mg/L,and ammonia nitrogen from 700 mg/L to 7 mg/L. The removal rate is respectively 99. 3 % and 99. 0 %. The cyanide and ammonia nitrogen concentration remained in the treated water has reached of Grade 1 requirements of Integrated waste water discharge standard ( GB 8978 - 1996). The power consumption per ton water is 13.1 kw·h.%对黄金冶炼废水进行了电催化氧化处理研究,考察了氯离子质量浓度、极板间距、电流密度等因素对氰化物和氨氮去除效果的影响.最佳工艺参数为:废水初始pH值9.28、氯离子初始质量浓度25 g/L、极板间距20 mm、电流密度16.3 mA/cm2、废水循环流速64 mL/min.在最佳工艺条件下,电解150 min,氰化物质量浓度从28.84 mg/L降至0.20 mg/L,氨氮质量浓度从700 mg/L降至7 mg/L,去除率分别为99.3%、99.0%,处理后废水中的总氰、氨氮均可达到《GB 8978-1996污水综合排放标准》一级标准.

  4. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  5. Molecular catalytic coal liquid conversion

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.; Yang, Shiyong [Univ. of Chicago, IL (United States)

    1995-12-31

    This research, which is relevant to the development of new catalytic systems for the improvement of the quality of coal liquids by the addition of dihydrogen, is divided into two tasks. Task 1 centers on the activation of dihydrogen by molecular basic reagents such as hydroxide ion to convert it into a reactive adduct (OH{center_dot}H{sub 2}){sup {minus}} that can reduce organic molecules. Such species should be robust withstanding severe conditions and chemical poisons. Task 2 is focused on an entirely different approach that exploits molecular catalysts, derived from organometallic compounds that are capable of reducing monocyclic aromatic compounds under very mild conditions. Accomplishments and conclusions are discussed.

  6. Computational Introduction of Catalytic Activity into Proteins.

    Science.gov (United States)

    Bertolani, Steve J; Carlin, Dylan Alexander; Siegel, Justin B

    2016-01-01

    Recently, there have been several successful cases of introducing catalytic activity into proteins. One method that has been used successfully to achieve this is the theozyme placement and enzyme design algorithms implemented in Rosetta Molecular Modeling Suite. Here, we illustrate how to use this software to recapitulate the placement of catalytic residues and ligand into a protein using a theozyme, protein scaffold, and catalytic constraints as input. PMID:27094294

  7. Estimating the temperature of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-02

    A method is described for estimating the temperature in a catalytic converter used in the exhaust system of an internal combustion engine. Pressure sensors monitor the flow resistance across the catalytic converter to provide an indication of the temperature inside. This feedback system allows heating devices to be switched off and thus avoid overheating, while maintaining the catalytic converter's efficiency by assuring that it does not operate below its light off temperature. (UK)

  8. Estimating the temperature of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-02

    A method of estimating the temperature of a catalytic converter used in the exhaust system of an internal combustion engine is described. Heated exhaust gas oxygen (HEGO) sensors are placed upstream and downstream of the catalytic converter. The temperature of the catalytic converter shortly after start-up is measured by monitoring the resistance of the HEGO sensor's heating element. The downstream sensor is used for mixture control and to double check results of the upstream sensor. (UK)

  9. Some Aspects of the Catalytic Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Anil; K.Saikia

    2007-01-01

    1 Results Catalytic reactions are gaining importance due to its low cost, operational simplicity, high efficiency and selectivity. It is also getting much attention in green synthesis. Many useful organic reactions, including the acylation of alcohols and aldehydes, carbon-carbon, carbon-nitrogen, carbon-sulfur bond forming and oxidation reactions are carried out by catalyst. We are exploring the catalytic acylation of alcohols and aldehydes in a simple and efficient manner. Catalytic activation of unr...

  10. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  11. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  12. Catalytic reforming feed characterisation technique

    Energy Technology Data Exchange (ETDEWEB)

    Larraz Mora, R.; Arvelo Alvarez, R. [Univ. of La Laguna, Chemical Engineering Dept., La Laguna (Spain)

    2002-09-01

    The catalytic reforming of naphtha is one of the major refinery processes, designed to increase the octane number of naphtha or to produce aromatics. The naphtha used as catalytic reformer feedstock usually contains a mixture of paraffins, naphthenes, and aromatics in the carbon number range C{sub 6} to C{sub 10}. The detailed chemical composition of the feed is necessary to predict the aromatics and hydrogen production as well as the operation severity. The analysis of feed naphtha is usually reported in terms of its ASTM distillation curve and API or specific gravity. Since reforming reactions are described in terms of lumped chemical species (paraffins, naphthenes and aromatics), a feed characterisation technique should be useful in order to predict reforming operating conditions and detect feed quality changes. Unfortunately online analyzer applications as cromatography or recently introduced naphtha NMR [1] are scarce in most of refineries. This work proposes an algorithmic characterisation method focusing on its main steps description. The method could help on the subjects previously described, finally a calculation example is shown. (orig.)

  13. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  14. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H

  15. Catalytic partial oxidation of pyrolysis oils

    Science.gov (United States)

    Rennard, David Carl

    2009-12-01

    details the catalytic partial oxidation of glycerol without preheat: droplets of glycerol are sprayed directly onto the top of the catalyst bed, where they react autothermally with contact times on the order of tau ≈ 30 ms. The reactive flash volatilization of glycerol results in equilibrium syngas production over Rh-Ce catalysts. In addition, water can be added to the liquid glycerol, resulting in true autothermal reforming. This highly efficient process can increase H2 yields and alter the H2 to CO ratio, allowing for flexibility in syngas quality depending on the purpose. Chapter 5 details the results of a time on stream experiment, in which optimal syngas conditions are chosen. Although conversion is 100% for 450 hours, these experiments demonstrate the deactivation of the catalyst over time. Deactivation is exhibited by decreases in H2 and CO 2 production accompanied by a steady increase in CO and temperature. These results are explained as a loss of water-gas shift equilibration. SEM images suggest catalyst sintering may play a role; EDS indicates the presence of impurities on the catalyst. In addition, the instability of quartz in the reactor is demonstrated by etching, resulting in a hole in the reactor tube at the end of the experiment. These results suggest prevaporization may be desirable in this application, and that quartz is not a suitable material for the reactive flash volatilization of oxygenated fuels. In Chapter 6, pyrolysis oil samples from three sources - poplar, pine, and hardwoods - are explored in the context of catalytic partial oxidation. Lessons derived from the tests with model compounds are applied to reactor design, resulting in the reactive flash vaporization of bio oils. Syngas is successfully produced, though deactivation due to coke and ash deposition keeps H2 below equlibrium. Coke formation is observed on the reactor walls, but is avoided between the fuel injection site and catalyst by increasing the proximity of these in the reactor

  16. Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

    Directory of Open Access Journals (Sweden)

    Beixiao Zhang

    2010-08-01

    Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

  17. Newspaper and internet display advertising: Co-existence or substitution?

    OpenAIRE

    Lindstädt, Nadine; Budzinski, Oliver

    2012-01-01

    Newspapers have been experiencing declining circulation figures and diminishing advertising revenues for several years – both effects might pose a threat to the continuing existence of (print) newspapers. In an earlier paper, Lindstädt & Budzinski (2011) argued from a theoretical viewpoint that industry-specific patterns exist that determine substitution or complementation effects between internet and newspaper advertising. It was argued that retail advertising, in particular, may offer a nic...

  18. Autoimmune Diseases Co-Existing with Hepatitis C Virus Infection

    Directory of Open Access Journals (Sweden)

    Zohreh Jadali

    2010-12-01

    Full Text Available Autoimmunity and viral infections are closely associated fields, and viruses have been proposed as a likely aetiological, contributory or triggering factors of systemic autoimmune diseases. Hepatitis C virus seems to be the virus usually associated with the appearance of autoimmune diseases, and the relationship between chronic hepatitis C virus infection and some autoimmune disease has been studied. For some of these disorders their association with hepatitis C virus infection is well recognized while for others it remains probable or weak. Examples of autoimmune phenomena observed in chronic hepatitis C virus infection include rheumatoid arthritis, thyroid disease, cryoglobulinaemia, immune thrombocytopenic purpura, systemic lupus erythematosus and sjogren syndrome. To date, the etiological role and the pathogenetic involvement of the hepatitis C infection remains unknown.The aim of this study is to assess the presence of different autoimmune manifestations of hepatitis C virus infection reported in literature.

  19. Waste management and quality assurance: Reasonable co-existence?

    Energy Technology Data Exchange (ETDEWEB)

    Bresson, J.F.

    1989-11-01

    Implementing Chapter 3, Low-Level Waste Management, of DOE Order 5820-2, ``Radioactive Waste Management`` has created a major change in the operating philosophy of DOE`s prime contractors. So has the decision of May 1, 1987, when it was made clear that EPA has regulatory authority over DOE`s mixed waste. Suddenly two additional items became clear. First, DOE and its contractors were going to learn more about composition of low-level and low-level mixed waste than ever before. Second, low-level waste management was about to become a more focused, formal program, complete with needs for: (1) waste form identification, (2) program documentation; and (3) assurance that DOE`s waste does in fact comply with applicable requirements. The importance of the above items is clearly emphasized by the inclusion of Data Quality Objectives in the Waste Acceptance Criteria section of DOE 5820-2 Chapter 3 guidance called Data Quality Objectives, (DQO). Simply put, the purpose of the DQO is to identify the quality (and quantity) of information necessary to convince a regulator or decision maker that enough is known about DOE`s low-level and low-level mixed waste to allow safe disposal. The main objectives of the DOE and EPA shallow land burial requirements are to: (1) generate, with documented evidence, waste forms which are chemically inert and immobile, such that the waste will not tend to move about in the disposal medium; (2) select a disposal medium which would not let the wastes move about anyway; and (3) build some barriers around the wastes as emplaced in burial grounds, to provide additional assurance that buried wastes will stay in place. Compliance with these requirements must be demonstrated by quality data which describes the entire series of compliance activities.

  20. Perceptual similarity co-existing with lexical dissimilarity

    Science.gov (United States)

    Weber, Andrea; Cutler, Anne

    2003-10-01

    The extreme case of perceptual similarity is indiscriminability, as when two second-language phonemes map to a single native category. An example is the English had-head vowel contrast for Dutch listeners; Dutch has just one such central vowel, transcribed [E]. We examine whether the failure to discriminate in phonetic categorization implies indiscriminability in other-e.g., lexical-processing. Eyetracking experiments show that Dutch-native listeners instructed in English to ``click on the panda'' look (significantly more than native listeners) at a pictured pencil, suggesting that pan- activates their lexical representation of pencil. The reverse, however, is not the case: ``click on the pencil'' does not induce looks to a panda, suggesting that pen- does not activate panda in the lexicon. Thus prelexically undiscriminated second-language distinctions can nevertheless be maintained in stored lexical representations. The problem of mapping a resulting unitary input to two distinct categories in lexical representations is solved by allowing input to activate only one second-language category. For Dutch listeners to English, this is English [E], as a result of which no vowels in the signal ever map to words containing [ae]. We suggest that the choice of category is here motivated by a more abstract, phonemic, metric of similarity.

  1. The Co-existence of Innovation and Platforms

    DEFF Research Database (Denmark)

    Hansen, Poul H. Kyvsgård; Gertsen, Frank; Bessant, John

    2006-01-01

    This paper present explorative results from an initial effort to explore the current state and the actual requirements to combine the challenges in meeting the need for efficient platforms and the need for effectiveness in terms of a sufficient high degree of newness to the customer. Empirical ob...

  2. Electrical signaling and photosynthesis: Can they co-exist together?

    OpenAIRE

    Pavlovič, Andrej; Mancuso, Stefano

    2011-01-01

    Mechanical irritation of trigger hairs and subsequent generation of action potentials have significant impact on photosynthesis and respiration in carnivorous Venus flytrap (Dionaea muscipula). Action potential-mediated inhibition of photosynthesis and stimulation of respiration is confined only to the trap and was not recorded in adjacent photosynthetic lamina. We showed that the main primary target of electrical signals on assimilation is in the dark enzymatic reaction of photosynthesis. Wi...

  3. Dams and river dolphins: Can they co-exist?

    International Nuclear Information System (INIS)

    Dam construction is one of many ways that humans have modified river-dolphin habitats. It is suggested that physiographic and hydrologic complexity plays an important role in making rivers suitable for dolphins. If this hypothesis is true, then it can be assumed that dams and other artificial obstructions degrade dolphin habitat insofar as they reduce such complexity. This paper identifies some of the impacts that dams, barrages, and dikes might have on dolphins. Research is needed at project sites, both before and after construction, to document impacts. Specially designed ''swimways'' may allow upstream and downstream passage by dolphins and thus mitigate at least one of the adverse effects of dam projects, namely population fragmentation, but such measures aimed at benefiting single species are no substitute for protecting ecosystems. 30 refs

  4. Tobacco or healthy children: the two cannot co-exist

    Directory of Open Access Journals (Sweden)

    Philip Keith Pattemore

    2013-08-01

    Full Text Available Tobacco exposure increases mortality and morbidity of the fetus, the child, the adolescent, and their children in turn. Nearly half the children in the world are exposed. Smoking is not merely personal choice or personal responsibility; those subtle phrases undermine those who have no choice in the matter.Tobacco control must take a multi-pronged attack. Smoking cessation by adults in childbearing years must take centre stage of these efforts, because it is the only way to ensure a smoke-free environment for children. Smoke-free parents provide a role model for smoke-free young people, and erode the image of smoking as a desirable adult behaviour to emulate. Pediatricians and pediatric pulmonologists have a key role to play here. This goal will reduce morbidity and mortality among adults and children. Legislation regarding taxation, environments, tobacco constituents, product placement and display, packaging, and media education are all key to this core goal. Smokefree policy must be protected from attack based on trade agreements.Research is needed into more effective ways to attract and help people give up smoking, and into educating and re-deploying tobacco industry workers in emerging and developed countries.

  5. Molar Pregnancy with a Co-Existing Viable Fetus

    OpenAIRE

    Ruya Deveer

    2014-01-01

        The aim of this study was to report the clinical features, management, and outcome of a case of molar pregnancy with a coexisting viable fetus and to review the literature. In this article, we report a case of pregnancy with diffuse placental molar change and a normal fetus which presented with hyperemesis gravidarum and hyperthyroidism. Genetic amniocentesis showed normal fetal karyotype. A healthy full-term live male infant was delivered by cesarean section. In molar preg...

  6. Fabrication of MgAl2Si2O8 : M0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+): catalytic effects for the reduction of 2- or 4-nitroanilines in water

    Indian Academy of Sciences (India)

    Serkan Dayan; Sevgi Öztürk; Nilgün Kayaci; Nilgun Kalaycioglu Ozpozan; Esra Öztürk

    2015-10-01

    Five new MgAl2Si2O8 : M0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+) materials were developed for the reduction of nitroarenes as catalysts by conventional solid state reaction at 1300°C. The prepared materials were characterized by thermal analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, scanning electron microscopy, energy-dispersive X-ray analysis and nitrogen adsorption–desorption analysis. The catalytic activities of the prepared catalysts were tested in the reduction of 2- or 4-nitroanilines in aqueous media at ambient temperature in the presence of NaBH4 by UV–vis spectrophotometer. Furthermore, the MgAl2Si2O8 : M0.01 catalysts can be recovered by filtration and reused for five cycles for the reduction of 2-nitroaniline. These results show that the MgAl2Si2O8 : M0.01 catalysts can be used in practical applications in the reduction of nitroanilines.

  7. Process design for wastewater treatment: catalytic ozonation of organic pollutants.

    Science.gov (United States)

    Derrouiche, S; Bourdin, D; Roche, P; Houssais, B; Machinal, C; Coste, M; Restivo, J; Orfão, J J M; Pereira, M F R; Marco, Y; Garcia-Bordeje, E

    2013-01-01

    Emerging micropollutants have been recently the target of interest for their potential harmful effects in the environment and their resistance to conventional water treatments. Catalytic ozonation is an advanced oxidation process consisting of the formation of highly reactive radicals from the decomposition of ozone promoted by a catalyst. Nanocarbon materials have been shown to be effective catalysts for this process, either in powder form or grown on the surface of a monolithic structure. In this work, carbon nanofibers grown on the surface of a cordierite honeycomb monolith are tested as catalyst for the ozonation of five selected micropollutants: atrazine (ATZ), bezafibrate, erythromycin, metolachlor, and nonylphenol. The process is tested both in laboratorial and real conditions. Later on, ATZ was selected as a target pollutant to further investigate the role of the catalytic material. It is shown that the inclusion of a catalyst improves the mineralization degree compared to single ozonation. PMID:24056437

  8. Effect of plant cultivation,phosphorus fertilization and co-existing polycyclic aromatic hydrocarbons (PAHs) on biodegradation of PAHs%植物、施磷量及多环芳烃共存对多环芳烃生物降解影响

    Institute of Scientific and Technical Information of China (English)

    周笑白; 周集体; 项学敏

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with toxic, mutagenic and carcingenic properties. Pot experiment and microplate experiments are conducted to investigate the impact of plant cultivation, phosphorus fertilization and PAHs co-existence on the removal rate of phenanthracene (PHE), pyrene (PYR) and dihenzo [a, hi anthracene (DBA). Results show that the dissipation and degraders of PHE are significantly higher than those of PYR and DBA in both pot and microplate experiments. In pot experiment, plants and higher quantity of phosphorus fertilizer increase DBA dissipation. Different interactions are obtained among the co- existing PAHs. The results show that co-existence of different PAH compounds can lead to synergistic co-metabolism (PHE enhanced DBA degradation), no co-metabolism (PYR and DBA) and inhibition of PAH degradation (PYR inhibited PHE+DBA degradation). The positive effect of PHE on DBA dissipation decreases with time course, which is probably due to the decrease of PHE concentration or the toxicity and accumulation of DBA degradation products in the substrate.%多环芳烃(PAHs)是具有“三致”效应的持久性有机污染物.通过盆栽及微生物培养实验,考察了植物、施磷量及PAHs共存对菲(PHE)、芘(PYR)和二苯并葸(DBA)去除率的影响,发现PHE的降解率和降解菌量均高于PYR和DBA.盆栽实验中,植物种植和给植物施加高磷浓度的营养液可促进DBA的降解;微生物培养实验表明共存的PAHs之间存在相互作用,而这种作用随PAHs种类不同可表现为促进降解作用(如PHE促进DBA降解)、无作用(如PYR和DBA)或抑制作用(如PYR抑制PHE+DBA降解).PHE对DBA降解的促进作用随时间的增加而减弱,这可能与PHE浓度降低和DBA中间产物的毒性及其积累有关.

  9. Catalytic strategy used by the myosin motor to hydrolyze ATP.

    Science.gov (United States)

    Kiani, Farooq Ahmad; Fischer, Stefan

    2014-07-22

    Myosin is a molecular motor responsible for biological motions such as muscle contraction and intracellular cargo transport, for which it hydrolyzes adenosine 5'-triphosphate (ATP). Early steps of the mechanism by which myosin catalyzes ATP hydrolysis have been investigated, but still missing are the structure of the final ADP·inorganic phosphate (Pi) product and the complete pathway leading to it. Here, a comprehensive description of the catalytic strategy of myosin is formulated, based on combined quantum-classical molecular mechanics calculations. A full exploration of catalytic pathways was performed and a final product structure was found that is consistent with all experiments. Molecular movies of the relevant pathways show the different reorganizations of the H-bond network that lead to the final product, whose γ-phosphate is not in the previously reported HPγO4(2-) state, but in the H2PγO4(-) state. The simulations reveal that the catalytic strategy of myosin employs a three-pronged tactic: (i) Stabilization of the γ-phosphate of ATP in a dissociated metaphosphate (PγO3(-)) state. (ii) Polarization of the attacking water molecule, to abstract a proton from that water. (iii) Formation of multiple proton wires in the active site, for efficient transfer of the abstracted proton to various product precursors. The specific role played in this strategy by each of the three loops enclosing ATP is identified unambiguously. It explains how the precise timing of the ATPase activation during the force generating cycle is achieved in myosin. The catalytic strategy described here for myosin is likely to be very similar in most nucleotide hydrolyzing enzymes.

  10. Acoustics of automotive catalytic converter assemblies

    Science.gov (United States)

    Dickey, Nolan S.; Selamet, Ahmet; Parks, Steve J.; Tallio, Kevin V.; Miazgowicz, Keith D.; Radavich, Paul M.

    2003-10-01

    In an automotive exhaust system, the purpose of the catalytic converter is to reduce pollutant emissions. However, catalytic converters also affect the engine and exhaust system breathing characteristics; they increase backpressure, affect exhaust system acoustic characteristics, and contribute to exhaust manifold tuning. Thus, radiated sound models should include catalytic converters since they can affect both the source characteristics and the exhaust system acoustic behavior. A typical catalytic converter assembly employs a ceramic substrate to carry the catalytically active noble metals. The substrate has numerous parallel tubes and is mounted in a housing with swelling mat or wire mesh around its periphery. Seals at the ends of the substrate can be used to help force flow through the substrate and/or protect the mat material. Typically, catalytic converter studies only consider sound propagation in the small capillary tubes of the substrate. Investigations of the acoustic characteristics of entire catalytic converter assemblies (housing, substrate, seals, and mat) do not appear to be available. This work experimentally investigates the acoustic behavior of catalytic converter assemblies and the contributions of the separate components to sound attenuation. Experimental findings are interpreted with respect to available techniques for modeling sound propagation in ceramic substrates.

  11. Understanding catalytic biomass conversion through data mining

    NARCIS (Netherlands)

    E.J. Ras; B. McKay; G. Rothenberg

    2010-01-01

    Catalytic conversion of biomass is a key challenge that we chemists face in the twenty-first century. Worldwide, research is conducted into obtaining bulk chemicals, polymers and fuels. Our project centres on glucose valorisation via furfural derivatives using catalytic hydrogenation. We present her

  12. Supercritical water

    CERN Document Server

    Marcus, Yizhak

    2012-01-01

    Discover the many new and emerging applications of supercritical water as a green solvent Drawing from thousands of original research articles, this book reviews and summarizes what is currently known about the properties and uses of supercritical water. In particular, it focuses on new and emerging applications of supercritical water as a green solvent, including the catalytic conversion of biomass into fuels and the oxidation of hazardous materials. Supercritical Water begins with an introduction that defines supercritical fluids in general. It then defines supercritical wa

  13. Esterification of glycerol from biodiesel production to glycerol carbonate in non-catalytic supercritical dimethyl carbonate.

    Science.gov (United States)

    Ilham, Zul; Saka, Shiro

    2016-01-01

    Conversion of glycerol from biodiesel production to glycerol carbonate was studied by esterification with dimethyl carbonate in a non-catalytic supercritical condition. It was found that in a non-catalytic supercritical condition, glycerol at higher purity gave higher yield of glycerol carbonate at 98 wt% after reaction at 300 °C/20-40 MPa/15 min. The yield of glycerol carbonate was observed to increase with molar ratio, temperature, pressure and time until a certain equilibrium limit. The existence of impurities such as water and remnants of alkaline catalyst in crude glycerol will direct the reaction to produce glycidol. Although impurities might not be desirable, the non-catalytic supercritical dimethyl carbonate could be an alternative method for conversion of glycerol from biodiesel production to value-added glycerol carbonate.Graphical abstractPlausible reaction scheme for conversion of glycerol to glycerol carbonate in non-catalytic supercritical dimethyl carbonate. PMID:27386367

  14. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  15. Reducing catalytic converter pressure loss

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This article examines why approximately 30--40% of total exhaust-system pressure loss occurs in the catalytic converter and what can be done to reduce pressure loss. High exhaust-system backpressure is of concern in the design of power trains for passenger cars and trucks because it penalizes fuel economy and limits peak power. Pressure losses occur due to fluid shear and turning during turbulent flow in the converter headers and in entry separation and developing laminar-flow boundary layers within the substrate flow passages. Some of the loss mechanisms are coupled. For example, losses in the inlet header are influenced by the presence of the flow resistance of a downstream substrate. Conversely, the flow maldistribution and pressure loss of the substrate(s) depend on the design of the inlet header.

  16. Non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  17. Catalytic Graphitization of Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    Mu Zhao; Huaihe Song

    2011-01-01

    The catalytic graphitization of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate (FN) was studied in detail. The morphologies and structural features of the products including onion-like carbon nanoparticles and bamboo-shaped carbon nanotubes were investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction and Raman spectroscopy measurements. It was found that with the changes of loading content of FN and residence time at 1000℃, the products exhibited various morphologies. The TEM images showed that bamboo-shaped carbon nanotube consisted of tens of bamboo sticks and onion-like carbon nanoparticle was made up of quasi-spherically concentrically closed carbon nanocages.

  18. Catalytic converter with thermoelectric generator

    Energy Technology Data Exchange (ETDEWEB)

    Parise, R.J.

    1998-07-01

    The unique design of an electrically heated catalyst (EHC) and the inclusion of an ECO valve in the exhaust of an internal combustion engine will meet the strict new emission requirements, especially at vehicle cold start, adopted by several states in this country as well as in Europe and Japan. The catalytic converter (CC) has been a most useful tool in pollution abatement for the automobile. But the emission requirements are becoming more stringent and, along with other improvements, the CC must be improved to meet these new standards. Coupled with the ECO valve, the EHC can meet these new emission limits. In an internal combustion engine vehicle (ICEV), approximately 80% of the energy consumed leaves the vehicle as waste heat: out the tail pipe, through the radiator, or convected/radiated off the engine. Included with the waste heat out the tail pipe are the products of combustion which must meet strict emission requirements. The design of a new CC is presented here. This is an automobile CC that has the capability of producing electrical power and reducing the quantity of emissions at vehicle cold start, the Thermoelectric Catalytic Power Generator. The CC utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. Thus an electrically heated catalyst (EHC) will be used to augment the abatement of tail pipe emissions. Included with the EHC in the exhaust stream of the automobile is the ECO valve. This valve restricts the flow of pollutants out the tail pipe of the vehicle for a specified amount of time until the EHC comes up to operating temperature. Then the ECO valve opens and allows the full exhaust, now treated by the EHC, to leave the vehicle.

  19. Influence of Co-existing Species on Charge Transfer in Dye-sensitized TiO2 Nanocrystalline System%共存牺牲剂对染料敏化TiO2纳米晶体系电子传输的影响

    Institute of Scientific and Technical Information of China (English)

    成荣敏; 李娜; 詹从红

    2014-01-01

    Dye-sensitized nanocrystalline TiO2 colloidal suspensions in aqueous system were applied for H2 evolution under visible light(>390 nm) . In these suspension systems, the efficiency of H2 evolution is strongly influenced by the dye-sensitizers, a ruthenium complex, (n-Bu4N)2-cis-[Ru(dcbpy)(SCN)2](N719, dcb-py=4,4’-dicarboxy-2,2’-bipyridine) and porphyrin derivatives 5,10,15,20-tetra(4-carboxyphenyl) porphyrin ( TCPP) and tetra-( p-sulfonato phenyl) porphyrin( TPPS) , and the combination with co-existing electron do-nor species, methanol ( MeOH ) and triethanolamine ( TEOA ) . The analysis of fluorescence quenching and photoelectrochemical studies reveal that the charge transfer between the excited dye-sensitizers and TiO2 is strongly influenced by the surroundings, especially the concentration of co-existing donor species rather than the pH values of the surrounding solution. It is benefit for achieving higher conversion efficiency for not only the photocatalysts but also the photovoltaics using dye-sensitized of TiO2 nanoparticles.%采用卟啉染料敏化TiO2纳米晶在可见光条件下(λ>390 nm)进行水分解制氢。考察了不同牺牲剂---甲醇( MeOH)、三乙醇胺( TEOA)及其混合物对体系析氢效率的影响。通过荧光猝灭及光电化学性能分析发现,激发态染料与TiO2之间的电子转移极大地受到添加的牺牲剂的影响,而体系的pH值对其影响不大。

  20. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  1. Catalytic glycerol steam reforming for hydrogen production

    Science.gov (United States)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  2. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Christpher P; Boldingh, Edwin P

    2013-12-17

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and show to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hyrdocarbons into hydrocarbons removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  3. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-10-07

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and shown to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub.1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  4. Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-12-01

    This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure

  5. Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Ekerdt, J.G.

    1992-02-03

    This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.

  6. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    International Nuclear Information System (INIS)

    The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize

  7. Synthesis, catalytic properties and biological activity of new water soluble ruthenium cyclopentadienyl PTA complexes [(C5R5)RuCl(PTA)2] (R = H, Me; PTA = 1,3,5-triaza-7-phosphaadamantane).

    Science.gov (United States)

    Akbayeva, Dina N; Gonsalvi, Luca; Oberhauser, Werner; Peruzzini, Maurizio; Vizza, Francesco; Brüggeller, Peter; Romerosa, Antonio; Sava, Gianni; Bergamo, Alberta

    2003-01-21

    The new water soluble ruthenium complexes [(C5R5)RuCl(PTA)2] (R = H, Me; PTA = 1,3,5-triaza-7-phosphaadamantane) were synthesised and characterised. Their evaluation as regioselective catalysts for hydrogenation of unsaturated ketones in aqueous biphasic conditions and as cytotoxic agents towards the TS/A adenocarcinoma cell line is briefly presented. PMID:12585422

  8. Development of Catalytic Cooking Plates

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden); Tena, Emmanuel; Berger, Marc [Gaz de France (France)

    2004-04-01

    Gas catalytic combustion for gas stoves or cooking plates (closed catalytic burner system with ceramic plates) is a very promising technique in terms of ease of cleaning, power modulation and emissions. Previous investigations show that wire mesh catalysts, prepared and supplied by Catator AB (CAT), seem to be very well suited for such applications. Beside significantly reducing the NOx-emissions, these catalysts offer important advantages such as good design flexibility, low pressure drop and high heat transfer capacity, where the latter leads to a quick thermal response. Prior to this project, Gaz de France (GdF) made a series of measurements with CAT's wire mesh catalysts in their gas cooking plates and compared the measured performance with similar results obtained with theirs cordierite monolith catalysts. Compared to the monolith catalyst, the wire mesh catalyst was found to enable very promising results with respect to both emission levels (<10 mg NO{sub x} /kWh, <5 mg CO/kWh) and life-time (>8000 h vs. 700 h at 200 kW/m{sup 2}). It was however established that the radiation and hence, the thermal efficiency of the cooking plate, was significantly less than is usually measured in combination with the monolith (15 % vs. 32 %). It was believed that the latter could be improved by developing new burner designs based on CAT's wire mesh concept. As a consequence, a collaboration project between GdF, CAT and the Swedish Gas Technology AB was created. This study reports on the design, the construction and the evaluation of new catalytic burners, based on CAT's wire mesh catalysts, used for the combustion of natural gas in gas cooking stoves. The evaluation of the burners was performed with respect to key factors such as thermal efficiency, emission quality and pressure drop, etc, by the use of theoretical simulations and experimental tests. Impacts of parameters such as the the wire mesh number, the wire mesh structure (planar or folded), the

  9. Catalytic reaction in confined flow channel

    Energy Technology Data Exchange (ETDEWEB)

    Van Hassel, Bart A.

    2016-03-29

    A chemical reactor comprises a flow channel, a source, and a destination. The flow channel is configured to house at least one catalytic reaction converting at least a portion of a first nanofluid entering the channel into a second nanofluid exiting the channel. The flow channel includes at least one turbulating flow channel element disposed axially along at least a portion of the flow channel. A plurality of catalytic nanoparticles is dispersed in the first nanofluid and configured to catalytically react the at least one first chemical reactant into the at least one second chemical reaction product in the flow channel.

  10. Vacuum-insulated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Benson, David K. (Golden, CO)

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  11. Catalytic Chemistry on Oxide Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Asthagiri, Aravind; Dixon, David A.; Dohnalek, Zdenek; Kay, Bruce D.; Rodriquez, Jose A.; Rousseau, Roger J.; Stacchiola, Dario; Weaver, Jason F.

    2016-05-29

    Metal oxides represent one of the most important and widely employed materials in catalysis. Extreme variability of their chemistry provides a unique opportunity to tune their properties and to utilize them for the design of highly active and selective catalysts. For bulk oxides, this can be achieved by varying their stoichiometry, phase, exposed surface facets, defect, dopant densities and numerous other ways. Further, distinct properties from those of bulk oxides can be attained by restricting the oxide dimensionality and preparing them in the form of ultrathin films and nanoclusters as discussed throughout this book. In this chapter we focus on demonstrating such unique catalytic properties brought by the oxide nanoscaling. In the highlighted studies planar models are carefully designed to achieve minimal dispersion of structural motifs and to attain detailed mechanistic understanding of targeted chemical transformations. Detailed level of morphological and structural characterization necessary to achieve this goal is accomplished by employing both high-resolution imaging via scanning probe methods and ensemble-averaged surface sensitive spectroscopic methods. Three prototypical examples illustrating different properties of nanoscaled oxides in different classes of reactions are selected.

  12. Halogen Chemistry on Catalytic Surfaces.

    Science.gov (United States)

    Moser, Maximilian; Pérez-Ramírez, Javier

    2016-01-01

    Halogens are key building blocks for the manufacture of high-value products such as chemicals, plastics, and pharmaceuticals. The catalytic oxidation of HCl and HBr is an attractive route to recover chlorine and bromine in order to ensure the sustainability of the production processes. Very few materials withstand the high corrosiveness and the strong exothermicity of the reactions and among them RuO2 and CeO2-based catalysts have been successfully applied in HCl oxidation. The search for efficient systems for HBr oxidation was initiated by extrapolating the results of HCl oxidation based on the chemical similarity of these reactions. Interestingly, despite its inactivity in HCl oxidation, TiO2 was found to be an outstanding HBr oxidation catalyst, which highlighted that the latter reaction is more complex than previously assumed. Herein, we discuss the results of recent comparative studies of HCl and HBr oxidation on both rutile-type (RuO2, IrO2, and TiO2) and ceria-based catalysts using a combination of advanced experimental and theoretical methods to provide deeper molecular-level understanding of the reactions. This knowledge aids the design of the next-generation catalysts for halogen recycling. PMID:27131113

  13. Insights into the mechanism of the reaction between tetrachloro-p-benzoquinone and hydrogen peroxide and their implications in the catalytic role of water molecules in producing the hydroxyl radial.

    Science.gov (United States)

    Li, Ping; Wang, Weihua; Sun, Qiao; Li, Zhen; Du, Aijun; Bi, Siwei; Zhao, Yan

    2013-08-26

    Detailed mechanisms for the formation of hydroxyl or alkoxyl radicals in the reactions between tetrachloro-p-benzoquinone (TCBQ) and organic hydroperoxides are crucial for better understanding the potential carcinogenicity of polyhalogenated quinones. Herein, the mechanism of the reaction between TCBQ and H2O2 has been systematically investigated at the B3LYP/6-311++G** level of theory in the presence of different numbers of water molecules. We report that the whole reaction can easily take place with the assistance of explicit water molecules. Namely, an initial intermediate is formed first. After that, a nucleophilic attack of H2O2 onto TCBQ occurs, which results in the formation of a second intermediate that contains an OOH group. Subsequently, this second intermediate decomposes homolytically through cleavage of the O-O bond to produce a hydroxyl radical. Energy analyses suggest that the nucleophilic attack is the rate-determining step in the whole reaction. The participation of explicit water molecules promotes the reaction significantly, which can be used to explain the experimental phenomena. In addition, the effects of F, Br, and CH3 substituents on this reaction have also been studied.

  14. A review of liquid-phase catalytic hydrodechlorination

    Directory of Open Access Journals (Sweden)

    Alba Nelly Ardila Arias

    2010-04-01

    Full Text Available This survey was aimed at introducing the effect of light organochlorinated compound emissions on the envi-ronment, particularly on water, air, soil, biota and human beings. The characteristics and advantages of liquid phase catalytic hydrodechlorination as a technology for degrading these chlorinated compounds is also outlined and the main catalysts used in the hydrodechlorination process are described. Special emphasis is placed on palladium catalysts, their activity, the nature of active species and deactivation. The effect of several parameters is introduced, such as HCl, solvent, base addition and type of reducing agent used. The main results of kinetic studies, reactors used and the most important survey conclusions are presented.

  15. Determination of Trace Titanium by Catalytic Kinetic Spectrophtometry

    Institute of Scientific and Technical Information of China (English)

    ZHAI Qing-zhou; ZHANG Hao

    2007-01-01

    The optimum conditions of discoloring reaction of DBM-arsenazo oxidized by potassium bromate and catalyzed by trace titanium ( Ⅳ ) are studied and a new catalytic-kinetic spectrophotometric method for determination of trace titanium is developed. The linear range of determination of titanium ( Ⅳ ) is 0 - 48 ng/mL at 530 nm. The detection limit of the method is 0.084 ng/mL. The method is used for the determination of titanium in water samples and the analytical results are in excellent agreement with those by atomic absorption spectrometry.

  16. Catalytic models developed through social work

    DEFF Research Database (Denmark)

    Jensen, Mogens

    2015-01-01

    The article develops the concept of catalytic processes in relation to social work with adolescents in an attempt to both reach a more nuanced understanding of social work and at the same time to develop the concept of catalytic processes in psychology. The social work is pedagogical treatment...... of adolescents placed in out-of-home care and is characterised using three situated cases as empirical data. Afterwards the concept of catalytic processes is briefly presented and then applied in an analysis of pedagogical treatment in the three cases. The result is a different conceptualisation of the social...... work with new possibilities of development of the work, but also suggestions for development of the concept of catalytic processes....

  17. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts

    KAUST Repository

    Imran, Ali

    2015-11-24

    Catalytic pyrolysis of wood with impregnated vegetable oil was investigated and compared with catalytic pyrolysis of jatropha cake making use of sodium based catalysts to produce a high quality bio-oil. The catalytic pyrolysis was carried out in two modes: in-situ catalytic pyrolysis and post treatment of the pyrolysis vapors. The in-situ catalytic pyrolysis was carried out in an entrained flow reactor system using a premixed feedstock of Na2CO3 and biomass and post treatment of biomass pyrolysis vapor was conducted in a downstream fixed bed reactor of Na2CO3/γ-Al2O3. Results have shown that both Na2CO3 and Na2CO3/γ-Al2O3 can be used for the production of a high quality bio-oil from catalytic pyrolysis of oil-impregnated-wood and jatropha cake. The catalytic bio-oil had very low oxygen content, water content as low as 1wt.%, a neutral pH, and a high calorific value upto 41.8MJ/kg. The bio-oil consisted of high value chemical compounds mainly hydrocarbons and undesired compounds in the bio-oil were either completely removed or considerably reduced. Increasing the triglycerides content (vegetable oil) in the wood enhanced the formation of hydrocarbons in the bio-oil. Post treatment of the pyrolysis vapor over a fixed bed of Na2CO3/γ-Al2O3 produced superior quality bio-oil compared to in-situ catalytic pyrolysis with Na2CO3. This high quality bio-oil may be used as a precursor in a fractionating process for the production of alternative fuels. © 2015 Elsevier B.V.

  18. MOBILE COMPLEX FOR CATALYTIC THERMAL WASTE TREATMENT

    Directory of Open Access Journals (Sweden)

    Vedi V.E.

    2012-12-01

    Full Text Available The design and purpose of the basic units of the mobile waste processing complex “MPK” are described. Experimental data of catalytic purification of exhaust gases are presented. Experimental data on catalytic clearing of final gases of a designed mobile incinerator plant are shown. It is defined, that concentrating of parasitic bridging in waste gases of the complex are considerably smaller, rather than allowed by normative documents.

  19. MOBILE COMPLEX FOR CATALYTIC THERMAL WASTE TREATMENT

    OpenAIRE

    Vedi V.E.; Rovenskii A.I.

    2012-01-01

    The design and purpose of the basic units of the mobile waste processing complex “MPK” are described. Experimental data of catalytic purification of exhaust gases are presented. Experimental data on catalytic clearing of final gases of a designed mobile incinerator plant are shown. It is defined, that concentrating of parasitic bridging in waste gases of the complex are considerably smaller, rather than allowed by normative documents.

  20. Catalytic Radical Domino Reactions in Organic Synthesis

    Science.gov (United States)

    Sebren, Leanne J.; Devery, James J.; Stephenson, Corey R.J.

    2014-01-01

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes. PMID:24587964

  1. Catalytic ammonia oxidation to nitrogen (I) oxide

    OpenAIRE

    MASALITINA NATALIYA YUREVNA; SAVENKOV ANATOLIY SERGEEVICH

    2015-01-01

    The process of synthesis of nitrous oxide by low-temperature catalytical oxidation of NH has been investigated for organic synthesis. The investigation has been carried out by the stage separation approach with NH oxidation occurring in several reaction zones, which characterized by different catalytic conditions. The selectivity for N₂O was 92–92,5 % at the ammonia conversion of 98–99.5 % in the optimal temperature range.

  2. Temperature Modulation of a Catalytic Gas Sensor

    OpenAIRE

    Eike Brauns; Eva Morsbach; Sebastian Kunz; Marcus Baeumer; Walter Lang

    2014-01-01

    The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response time, which allows advanced analysis of the sensor response. By using temperature modulation, additi...

  3. Preparation and Catalytic Oxidation Activity on 2-mercaptoethanol of a Novel Catalytic Cellulose Fibres

    Institute of Scientific and Technical Information of China (English)

    YAO Yu-yuan; LI Ying-jie; CHEN Wen-xing; Lü Wang-yang; Lü Su-fang; XU Min-hong; LIU Fan

    2007-01-01

    Cobalt tetra(N-carbonylacylic) aminophthalocyanine was supported on cellulose fibres by graft reaction to obtain a novel polymer catalyst, catalytic cellulose fibres (CCF),and the optimal supporting conditions were pH = 6, 80℃,t = 120 min. The catalytic oxidation activity of CCF towards oxidation of 2-mereaptoethanol (MEA) in aqueous solution was investigated. The experimental results demonstrated that CCF had good catalytic oxidation activity on MEA at room temperature, causing no secondary pollution and remaining efficient for the repetitive tests with no obvious decrease of catalytic activity.

  4. Synthesis of water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 and its catalytic application in Kabachnik-Fields multicomponent reaction

    Science.gov (United States)

    Rostamnia, Sadegh; Doustkhah, Esmail

    2015-07-01

    Water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 were successfully synthesized. β-Cyclodextrin acts as stabilizer and structure directing agent of Fe3O4. Subsequently, the dispersion of Fe3O4@β-CD was applied for the Kabachnik-Fields multicomponent reaction through three-component synthesis of an amine, aldehyde, and dimethylphosphonate. β-CD had also a drastic effect in accelerating the catalysis of phosphonate synthesis. By this protocol, phosphonate derivatives were synthesized in high yields and the catalyst was recycled for 10 successful runs.

  5. Low efficiency deasphalting and catalytic cracking

    International Nuclear Information System (INIS)

    This patent describes a process for converting an asphaltene and metals containing heavy hydrocarbon feed to lighter, more valuable products the metals comprising Ni and V. It comprises: demetallizing the feed by deasphalting the feed in a solvent deasphalting means operating at solvent deasphalting conditions including a solvent: feed volume ratio of about 1:1 to 4:1, using a solvent selected from the group of C4 to 400 degrees F. hydrocarbons and mixtures thereof; recovering from the solvent rich fraction a demetallized oil intermediate product, having a boiling range and containing at least 10 wt.% of the asphaltenes, and 5 to 30% of the Ni and V, and at least 10 wt.% of the solvent present in the solvent rich phase produced in the deasphalting means; catalytically cracking the demetallized oil intermediate product in a catalytic cracking means operating at catalytic cracking conditions to produce a catalytically cracked product vapor fraction having a lower boiling range than the boiling range of the demetallized oil intermediate product; and fractionating the catalytically cracked product in a fractionation means to produce catalytically cracked product fractions

  6. The Influence of Co existing Ions on Adsorping Cadmium in Water by Water-washing Waste Saccharomyces Cerevisiae%共存离子对水洗废啤酒酵母吸附水相中Cd2+的影响

    Institute of Scientific and Technical Information of China (English)

    代淑娟; 高太; 王玉娟; 刘文刚

    2008-01-01

    以水洗废啤酒酵母为吸附剂,以废水中镉离子对吸附对象,考察了重金属铜铅锌离子、碱土金属阳离子及一些负离子对吸附效果的影响.结果表明,重金属铜、铅、锌离子对吸附效果影响显著,而碱土金属离子及负离子对吸附效果影响相对较小.

  7. 再制造的行为模式:不完全竞争性与协同共生——基于产业组织理论视角的分析%Behavior Pattern of "Re-manufacturing": Imperfect Competition and Synergistic Co-existence --Analysis from the Perspective of Industrial Organization Theory

    Institute of Scientific and Technical Information of China (English)

    朱锐; 吴金明

    2012-01-01

    In accordance with the theory of industrial organization, re-manufacturing possess corporate behavior and market structure which under the conditions of imperfect competition, and have formed a unique pattern of behavior. This behavior pattern embodied in two aspects: imperfect competition and synergic co-existence. The nature of imperfect competition includes the targeting and oligopoly on used parts and remanufactured product's market, the entry barriers of technology and manufacturing modes, and government regulations on organization and business, etc. The collaborative co-existence comprises symbiosis of goals, collaboration of the business model, as well as vertical integration and vertical restraints based on the industry chain, etc. The two components of behavior model in manufacturing industry, exactly, leading to the shift down of manufacturing long-term cost curve, the finite change of optimal scale, and equally the e.nhancing of industrial concentration and monopoly. Moreover, this pattern has a profound impact on industry's market structure, efficiency and government policy.%按照产业组织理论,再制造具有不完全竞争条件下的企业行为与市场结构,并形成了独特的行为模式.这一行为模式集中体现在不完全竞争性与协同共生性两个方面:不完全竞争性包括对旧件和再制造产品市场的锁定与寡占、技术与制造模式的进入壁垒、组织与经营上的政府规制等方面,协同共生性包括目标上的共生、商业模式上的协同、基于产业链的垂直一体化和垂直约束等方面。正是再制造产业这种不完全竞争性与协同共生性.导致制造业长期成本曲线下移、最佳规模有限变动和产业集中度与垄断程度提升.并深刻影响制造业的市场结构、效率与政府政策。

  8. Catalytic hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, B.B.

    1992-12-01

    This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

  9. On the Structural Context and Identification of Enzyme Catalytic Residues

    OpenAIRE

    Yu-Tung Chien; Shao-Wei Huang

    2013-01-01

    Enzymes play important roles in most of the biological processes. Although only a small fraction of residues are directly involved in catalytic reactions, these catalytic residues are the most crucial parts in enzymes. The study of the fundamental and unique features of catalytic residues benefits the understanding of enzyme functions and catalytic mechanisms. In this work, we analyze the structural context of catalytic residues based on theoretical and experimental structure flexibility. The...

  10. Synthesis of water-dispersed magnetic nanoparticles (H{sub 2}O-DMNPs) of β-cyclodextrin modified Fe{sub 3}O{sub 4} and its catalytic application in Kabachnik–Fields multicomponent reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rostamnia, Sadegh, E-mail: srostamnia@gmail.com [Organic and Nano Group (ONG), Department of Chemistry, Faculty of Science, University of Maragheh, P.O. Box. 55181-83111, Maragheh (Iran, Islamic Republic of); Doustkhah, Esmail [Organic and Nano Group (ONG), Department of Chemistry, Faculty of Science, University of Maragheh, P.O. Box. 55181-83111, Maragheh (Iran, Islamic Republic of); Young Researchers and Elite Club, Maragheh Branch, Islamic Azad University, Maragheh (Iran, Islamic Republic of)

    2015-07-15

    Water-dispersed magnetic nanoparticles (H{sub 2}O-DMNPs) of β-cyclodextrin modified Fe{sub 3}O{sub 4} were successfully synthesized. β-Cyclodextrin acts as stabilizer and structure directing agent of Fe{sub 3}O{sub 4}. Subsequently, the dispersion of Fe{sub 3}O{sub 4}@β-CD was applied for the Kabachnik–Fields multicomponent reaction through three-component synthesis of an amine, aldehyde, and dimethylphosphonate. β-CD had also a drastic effect in accelerating the catalysis of phosphonate synthesis. By this protocol, phosphonate derivatives were synthesized in high yields and the catalyst was recycled for 10 successful runs. - Highlights: • Fe{sub 3}O{sub 4}@β-CD as a nanomagnetically catalyst. • A reusable magnetic nanocatalyst synthesis using commercially available compounds. • Represents advantages, operational simplicity, no waste, higher yield and with easy workup.

  11. Determination of Trace Mercury by Catalytic Solid Substrate-room Temperature Phosphorimetry

    Institute of Scientific and Technical Information of China (English)

    Jia Ming LIU; Yun Xiong WU; Shao Xian LIN; Fei Ming LI; Xiu Mei SHI; Zhong Bin SHI; Guo Hui ZHU; Zhi Ming LI; Xiao Mei HUANG

    2006-01-01

    A new highly sensitive method (detection limit: 4.1 ag spot-1, sample volume: 0.4 μL spot-1) for the determination of trace Hg2+ by catalytic solid substrate-room temperature phosphorimetry has been established in this paper. This method has been successfully applied to determine trace Hg2+ in water.

  12. Catalytic coal liquefaction. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Weller, S W

    1981-01-01

    Monolith catalysts of MoO/sub 3/-CoO-Al/sub 2/O/sub 3/ were prepared and tested for coal liquefaction in a stirred autoclave. In general, the monolith catalysts were not as good as particulate catalysts prepared on Corning alumina supports. Measurement of O/sub 2/ chemisorption and BET surface area has been made on a series of Co/Mo/Al/sub 2/O/sub 3/ catalysts obtained from PETC. The catalysts were derived from Cyanamid 1442A and had been tested for coal liquefaction in batch autoclaves and continuous flow units. MoO/sub 3/-Al/sub 2/O/sub 3/ catalysts over the loading range 3.9 to 14.9 wt % MoO/sub 3/ have been studied with respect to BET surface (before and after reduction), O/sub 2/ chemisorption at -78/sup 0/C, redox behavior at 500/sup 0/C, and activity for cyclohexane dehydrogenation at 500/sup 0/C. In connection with the fate of tin catalysts during coal liquefaction, calculations have been made of the relative thermodynamic stability of SnCl/sub 2/, Sn, SnO/sub 2/, and SnS in the presence of H/sub 2/, HCl, H/sub 2/S and H/sub 2/O. Ferrous sulfate dispersed in methylnaphthalene has been shown to be reduced to ferrous sulfide under typical coal hydroliquefaction conditions (1 hour, 450/sup 0/C, 1000 psi initial p/sub H/sub 2//). This suggests that ferrous sulfide may be the common catalytic ingredient when either (a) ferrous sulfate impregnated on powdered coal, or (b) finely divided iron pyrite is used as the catalyst. Old research on impregnated ferrous sulfate, impregnated ferrous halides, and pyrite is consistent with this assumption. Eight Co/Mo/Al/sub 2/O/sub 3/ catalysts from commercial suppliers, along with SnCl/sub 2/, have been studied for the hydrotreating of 1-methylnaphthalene (1-MN) in a stirred autoclave at 450 and 500/sup 0/C.

  13. Biodiesel from waste cooking oil via base-catalytic and supercritical methanol transesterification

    Energy Technology Data Exchange (ETDEWEB)

    Demirbas, Ayhan [Sila Science, Trabzon 61040 (Turkey)

    2009-04-15

    In this study, waste cooking oil has subjected to transesterification reaction by potassium hydroxide (KOH) catalytic and supercritical methanol methods obtaining for biodiesel. In catalyzed methods, the presence of water has negative effects on the yields of methyl esters. In the catalytic transesterification free fatty acids and water always produce negative effects since the presence of free fatty acids and water causes soap formation, consumes catalyst, and reduces catalyst effectiveness. Free fatty acids in the waste cooking oil are transesterified simultaneously in supercritical methanol method. Since waste cooking oil contains water and free fatty acids, supercritical transesterification offers great advantage to eliminate the pre-treatment and operating costs. The effects of methanol/waste cooking oils ratio, potassium hydroxide concentration and temperature on the biodiesel conversion were investigated. (author)

  14. A novel liquid system of catalytic hydrogenation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis that endothermic aqueous-phase reforming of oxygenated hydrocarbons for H2 production and exothermic liquid phase hydrogenation of organic compounds are carried out under extremely close conditions of temperature and pressure over the same type of catalyst, a novel liquid system of catalytic hydrogenation has been proposed, in which hydrogen produced from aqueous-phase reforming of oxygenated hydrocarbons is in situ used for liquid phase hydrogenation of organic compounds. The usage of active hydrogen generated from aqueous-phase reforming of oxygenated hydrocarbons for liquid catalytic hydrogenation of organic compounds could lead to increasing the selectivity to H2 in the aqueous-phase reforming due to the prompt removal of hydrogen on the active centers of the catalyst. Meanwhile, this novel liquid system of catalytic hydrogenation might be a potential method to improve the selectivity to the desired product in liquid phase catalytic hydrogenation of organic compounds. On the other hand, for this novel liquid system of catalytic hydrogenation, some special facilities for H2 generation, storage and transportation in traditional liquid phase hydrogenation industry process are yet not needed. Thus, it would simplify the working process of liquid phase hydrogenation and increase the energy usage and hydrogen productivity.

  15. Azomethine Ylides from Nitrones: Using Catalytic nBuLi for the Totally Stereoselective Synthesis of trans-2-Alkyl-3-oxazolines.

    Science.gov (United States)

    Juste-Navarro, Veronica; Delso, Ignacio; Tejero, Tomás; Merino, Pedro

    2016-08-01

    The cycloaddition of azomethine ylide N-oxides (nitrone ylides) with aldehydes provides 3-oxazolines in a completely stereoselective manner in the presence of a catalytic amount of n-butyllithium. The process involves an initial nucleophilic attack on the aldehyde, followed by intramolecular oxygen addition to the nitrone moiety and lithium-assisted elimination of water, regenerating the catalytic species. Various Li-based catalytic systems are possible and the in situ generated water is required for continuing the catalytic cycle. The best results are observed with 20 mol % of n-butyllithium, whereas the use of stoichiometric amounts inhibit the rate of catalysis. Experimental, spectroscopic, and computational mechanistic studies have provided evidence of lithium-ion catalysis and rationalized several competing catalytic pathways. PMID:27258625

  16. A theoretical study on the catalytic effect of nanoparticle confined in carbon nanotube

    Science.gov (United States)

    Qin, Wu; Li, Xin

    2011-01-01

    We investigated the catalytic effect of CuO nanoparticles confined in carbon nanotubes using molecular dynamics simulations and density functional theory calculations. Ozone decomposition and hydroxyl radical generation were used as the probe reactions to investigate the catalytic behavior of catalyst. The effects of the confined environment of carbon nanotubes induced more reactants into the channel. Interface interactions between reactants and CuO nanoparticles in the channel and charge transfer accelerated the decomposition of ozone into oxygen molecule and atomic oxygen species. The atomic oxygen species then interacted to water molecule to generate hydroxyl radicals, which were truly identified by electron paramagnetic resonance (EPR) technique.

  17. Ozone catalytic oxidation of benzene over AgMn/HZSM-5 catalysts at room temperature:Effects of Mn loading and water content%AgMn/HZSM-5催化剂上室温O3氧化脱除空气中的苯:Mn含量和水含量的影响

    Institute of Scientific and Technical Information of China (English)

    刘阳; 李小松; 刘景林; 石川; 朱爱民

    2014-01-01

    考察了Mn含量和水含量对AgMn/HZSM-5(AgMn/HZ)催化剂上室温O3氧化(OZCO)脱除空气中苯的影响.研究发现, Mn含量为2.4 wt%的AgMn/HZ催化剂(AgMn/HZ(2.4))具有大的比表面积和高的MnOx分散度, OZCO活性和稳定性最高.反应后的程序升温脱附结果表明,2.4 wt%的Mn含量能有效抑制苯和甲酸在催化剂上的残留.当Mn含量≤2.4 wt%时,催化剂分解O3的活性在苯氧化过程中占主导;当Mn含量>2.4 wt%时,苯的活化起主要作用.基于AgMn/HZ(2.4)催化剂优越的反应活性和稳定性,进一步研究了湿气流中该催化剂上苯的氧化.与干气流相比,水汽的加入能显著提高催化剂的反应活性和稳定性,且以0.1-0.2 vol%水含量时最优.%The effects of Mn loading and water content on AgMn/HZSM-5 (AgMn/HZ) catalysts were investi-gated in the ozone catalytic oxidation (OZCO) of benzene in a continuous air flow at room tempera-ture. The catalytic activity is closely related to the Mn loading, and the AgMn/HZ catalyst with 2.4 wt%Mn (AgMn/HZ(2.4)) had the highest activity and stability in benzene oxidation as a result of its large surface area and high MnOx dispersion. Temperature-programmed desorption of the used catalysts demonstrated that 2.4 wt%was also the optimal Mn loading for suppressing the accumu-lation of benzene and HCOOH over the catalyst surface after benzene oxidation. For AgMn/HZ cata-lysts with Mn loadings≤2.4 wt%, O3 decomposition to active oxygen species (O*) plays the most important role in benzene oxidation;however, benzene activation is the crucial step for benzene oxidation by O3 over AgMn/HZ catalysts with Mn loadings>2.4 wt%. The AgMn/HZ(2.4) catalyst was then used to perform OZCO of benzene in a humid stream. Compared with dry gas, water vapor greatly enhanced the activity and stability of the AgMn/HZ(2.4) catalyst, and 0.1-0.2 vol%was the optimal water content for benzene oxidation.

  18. Catalytic nanoarchitectonics for environmentally compatible energy generation

    Directory of Open Access Journals (Sweden)

    Hideki Abe

    2016-01-01

    Full Text Available Environmentally compatible energy management is one of the biggest challenges of the 21st century. Low-temperature conversion of chemical to electrical energy is of particular importance to minimize the impact to the environment while sustaining the consumptive economy. In this review, we shed light on one of the most versatile energy-conversion technologies: heterogeneous catalysts. We establish the integrity of structural tailoring in heterogeneous catalysts at different scales in the context of an emerging paradigm in materials science: catalytic nanoarchitectonics. Fundamental backgrounds of energy-conversion catalysis are first provided together with a perspective through state-of-the-art energy-conversion catalysis including catalytic exhaust remediation, fuel-cell electrocatalysis and photosynthesis of solar fuels. Finally, the future evolution of catalytic nanoarchitectonics is overviewed: possible combinations of heterogeneous catalysts, organic molecules and even enzymes to realize reaction-selective, highly efficient and long-life energy conversion technologies which will meet the challenge we face.

  19. ADAR proteins: structure and catalytic mechanism.

    Science.gov (United States)

    Goodman, Rena A; Macbeth, Mark R; Beal, Peter A

    2012-01-01

    Since the discovery of the adenosine deaminase (ADA) acting on RNA (ADAR) family of proteins in 1988 (Bass and Weintraub, Cell 55:1089-1098, 1988) (Wagner et al. Proc Natl Acad Sci U S A 86:2647-2651, 1989), we have learned much about their structure and catalytic mechanism. However, much about these enzymes is still unknown, particularly regarding the selective recognition and processing of specific adenosines within substrate RNAs. While a crystal structure of the catalytic domain of human ADAR2 has been solved, we still lack structural data for an ADAR catalytic domain bound to RNA, and we lack any structural data for other ADARs. However, by analyzing the structural data that is available along with similarities to other deaminases, mutagenesis and other biochemical experiments, we have been able to advance the understanding of how these fascinating enzymes function. PMID:21769729

  20. Catalytic Organic Transformations Mediated by Actinide Complexes

    Directory of Open Access Journals (Sweden)

    Isabell S. R. Karmel

    2015-10-01

    Full Text Available This review article presents the development of organoactinides and actinide coordination complexes as catalysts for homogeneous organic transformations. This chapter introduces the basic principles of actinide catalysis and deals with the historic development of actinide complexes in catalytic processes. The application of organoactinides in homogeneous catalysis is exemplified in the hydroelementation reactions, such as the hydroamination, hydrosilylation, hydroalkoxylation and hydrothiolation of alkynes. Additionally, the use of actinide coordination complexes for the catalytic polymerization of α-olefins and the ring opening polymerization of cyclic esters is presented. The last part of this review article highlights novel catalytic transformations mediated by actinide compounds and gives an outlook to the further potential of this field.

  1. Highly Dense Isolated Metal Atom Catalytic Sites

    DEFF Research Database (Denmark)

    Chen, Yaxin; Kasama, Takeshi; Huang, Zhiwei;

    2015-01-01

    -ray diffraction. A combination of electron microscopy images with X-ray absorption spectra demonstrated that the silver atoms were anchored on five-fold oxygen-terminated cavities on the surface of the support to form highly dense isolated metal active sites, leading to excellent reactivity in catalytic oxidation......Atomically dispersed noble-metal catalysts with highly dense active sites are promising materials with which to maximise metal efficiency and to enhance catalytic performance; however, their fabrication remains challenging because metal atoms are prone to sintering, especially at a high metal...... loading. A dynamic process of formation of isolated metal atom catalytic sites on the surface of the support, which was achieved starting from silver nanoparticles by using a thermal surface-mediated diffusion method, was observed directly by using in situ electron microscopy and in situ synchrotron X...

  2. Reactivity of organic compounds in catalytic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Minachev, Kh.M.; Bragin, O.V.

    1978-01-01

    A comprehensive review of 1976 Soviet research on catalysis delivered to the 1977 annual session of the USSR Academy of Science Council on Catalysis (Baku 6/16-20/77) covers hydrocarbon reactions, including hydrogenation and hydrogenolysis, dehydrogenation, olefin dimerization and disproportionation, and cyclization and dehydrocyclization (e.g., piperylene cyclization and ethylene cyclotrimerization); catalytic and physicochemical properties of zeolites, including cracking, dehydrogenation, and hydroisomerization catalytic syntheses and conversion of heterocyclic and functional hydrocarbon derivatives, including partial and total oxidation (e.g., of o-xylene to phthalic anhydride); syntheses of thiophenes from alkanes and hydrogen sulfide over certain dehydrogenation catalysts; catalytic syntheses involving carbon oxides ( e.g., the development of a new heterogeneous catalyst for hydroformylation of olefins), and of Co-MgO zeolitic catalysts for synthesis of aliphatic hydrocarbons from carbon dioxide and hydrogen, and fabrication of high-viscosity lubricating oils over bifunctional aluminosilicate catalysts.

  3. Catalytic microreactors for portable power generation

    Energy Technology Data Exchange (ETDEWEB)

    Karagiannidis, Symeon [Paul Scherer Institute, Villigen (Switzerland)

    2011-07-01

    ''Catalytic Microreactors for Portable Power Generation'' addresses a problem of high relevance and increased complexity in energy technology. This thesis outlines an investigation into catalytic and gas-phase combustion characteristics in channel-flow, platinum-coated microreactors. The emphasis of the study is on microreactor/microturbine concepts for portable power generation and the fuels of interest are methane and propane. The author carefully describes numerical and experimental techniques, providing a new insight into the complex interactions between chemical kinetics and molecular transport processes, as well as giving the first detailed report of hetero-/homogeneous chemical reaction mechanisms for catalytic propane combustion. The outcome of this work will be widely applied to the industrial design of micro- and mesoscale combustors. (orig.)

  4. Use catalytic combustion for LHV gases

    Energy Technology Data Exchange (ETDEWEB)

    Tucci, E.R.

    1982-03-01

    This paper shows how low heating value (LHV) waste gases can be combusted to recover energy even when the gases won't burn in a normal manner. Significant energy and economic savings can result by adopting this process. Catalytic combustion is a heterogeneous surface-catalyzed air oxidation of fuel, gaseous or liquid, to generate thermal energy in a flameless mode. The catalytic combustion process is quite complex since it involves numerous catalytic surface and gas-phase chemical reactions. During low temperature surface-catalyzed combustion, as in start-up, the combustion stage is under kinetically controlled conditions. The discussion covers the following topics - combustor substrates; combustor washcoating and catalyzing; combustor operational modes (turbine or tabular modes); applications in coal gasification and in-situ gasification; waste process gases. 16 refs.

  5. Xylan-Degrading Catalytic Flagellar Nanorods.

    Science.gov (United States)

    Klein, Ágnes; Szabó, Veronika; Kovács, Mátyás; Patkó, Dániel; Tóth, Balázs; Vonderviszt, Ferenc

    2015-09-01

    Flagellin, the main component of flagellar filaments, is a protein possessing polymerization ability. In this work, a novel fusion construct of xylanase A from B. subtilis and Salmonella flagellin was created which is applicable to build xylan-degrading catalytic nanorods of high stability. The FliC-XynA chimera when overexpressed in a flagellin deficient Salmonella host strain was secreted into the culture medium by the flagellum-specific export machinery allowing easy purification. Filamentous assemblies displaying high surface density of catalytic sites were produced by ammonium sulfate-induced polymerization. FliC-XynA nanorods were resistant to proteolytic degradation and preserved their enzymatic activity for a long period of time. Furnishing enzymes with self-assembling ability to build catalytic nanorods offers a promising alternative approach to enzyme immobilization onto nanostructured synthetic scaffolds. PMID:25966869

  6. Electro Catalytic Oxidation (ECO) Operation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Jones

    2011-03-31

    The power industry in the United States is faced with meeting many new regulations to reduce a number of air pollutants including sulfur dioxide, nitrogen oxides, fine particulate matter, and mercury. With over 1,000 power plants in the US, this is a daunting task. In some cases, traditional pollution control technologies such as wet scrubbers and SCRs are not feasible. Powerspan's Electro-Catalytic Oxidation, or ECO{reg_sign} process combines four pollution control devices into a single integrated system that can be installed after a power plant's particulate control device. Besides achieving major reductions in emissions of sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), fine particulate matter (PM2.5) and mercury (Hg), ECO produces a highly marketable fertilizer, which can help offset the operating costs of the process system. Powerspan has been operating a 50-MW ECO commercial demonstration unit (CDU) at FirstEnergy Corp.'s R.E. Burger Plant near Shadyside, Ohio, since February 2004. In addition to the CDU, a test loop has been constructed beside the CDU to demonstrate higher NOx removal rates and test various scrubber packing types and wet ESP configurations. Furthermore, Powerspan has developed the ECO{reg_sign}{sub 2} technology, a regenerative process that uses a proprietary solvent to capture CO{sub 2} from flue gas. The CO{sub 2} capture takes place after the capture of NOx, SO{sub 2}, mercury, and fine particulate matter. Once the CO{sub 2} is captured, the proprietary solution is regenerated to release CO{sub 2} in a form that is ready for geological storage or beneficial use. Pilot scale testing of ECO{sub 2} began in early 2009 at FirstEnergy's Burger Plant. The ECO{sub 2} pilot unit is designed to process a 1-MW flue gas stream and produce 20 tons of CO{sub 2} per day, achieving a 90% CO{sub 2} capture rate. The ECO{sub 2} pilot program provided the opportunity to confirm process design and cost estimates, and prepare for large

  7. Catalytic oxidations by vanadium complexes

    OpenAIRE

    Ligtenbarg, A.G J; Hage, R.; Feringa, B. L.

    2003-01-01

    Vanadium haloperoxidases catalyse the oxidation of halides leading to halogenation of substrates or, in the absence of suitable substrates, to oxidation of hydrogen peroxide into singlet oxygen and water. Furthermore, V-haloperoxidases are capable to give enantioselective sulfoxidation under the appropriate conditions. The most interesting model compounds that have been synthesised and studied as bromination catalysts, and catalysts for, i.e. epoxidation, hydroxylation, sulfoxidation and alco...

  8. Effect of BaO on Catalytic Activity of Pt-Rh TWC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of BaO doping on the three-way catalytic activity of Pt-Rh catalyst and on water-gas shift were investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides of the fresh catalysts slightly differ from those of the aged catalysts, and the catalysts containing CeO2-ZrO2-BaO have lower lightoff temperature and better catalytic activity than these containing BaO and CeO2-ZrO2 after hydrothermal aging for 5 h at 1000 C. The catalysts were characterized by means of the temperature-programmed reduction (TPR) in hydrogen and the temperature-programmed desorption (TPD) in oxygen. It is confirmed that the suggested route of CeO2-ZrO2-BaO by coprecipitation can improve the catalytic activity of catalysts.

  9. Mutational analysis of a ras catalytic domain

    DEFF Research Database (Denmark)

    Willumsen, B M; Papageorge, A G; Kung, H F;

    1986-01-01

    We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-rasH transforming protein, which is closely related to the cellular rasH protein. The mutants displayed a wide range of in vitro biological activity, from those that induced focal...... transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic...

  10. Thermal and catalytic pyrolysis of plastic waste

    Directory of Open Access Journals (Sweden)

    Débora Almeida

    2016-02-01

    Full Text Available Abstract The amount of plastic waste is growing every year and with that comes an environmental concern regarding this problem. Pyrolysis as a tertiary recycling process is presented as a solution. Pyrolysis can be thermal or catalytical and can be performed under different experimental conditions. These conditions affect the type and amount of product obtained. With the pyrolysis process, products can be obtained with high added value, such as fuel oils and feedstock for new products. Zeolites can be used as catalysts in catalytic pyrolysis and influence the final products obtained.

  11. A catalytic surface for amyloid fibril formation

    Energy Technology Data Exchange (ETDEWEB)

    Hammarstroem, P; Ali, M M; Mishra, R; Tengvall, P; Lundstroem, I [Department of Physics, Biology and Chemistry, Linkoeping University, SE-581 83 Linkoeping (Sweden); Svensson, S [Astra Zeneca R and D, SE-151 85 Soedertaelje (Sweden)], E-mail: ingemar@ifm.liu.se

    2008-03-15

    A hydrophobic surface incubated in a solution of protein molecules (insulin monomers) was made into a catalytic surface for amyloid fibril formation by repeatedly incubate, rinse and dry the surface. The present contribution describes how this unexpected transformation occurred and its relation to rapid fibrillation of insulin solutions in contact with the surface. A tentative model of the properties of the catalytic surface is given, corroborated by ellipsometric measurements of the thickness of the organic layer on the surface and by atomic force microscopy. The surfaces used were spontaneously oxidized silicon made hydrophobic through treatment in dichlorodimethylsilane.

  12. Catalytic gasification of oil-shales

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.; Avakyan, T. [I.M. Gubkin Russian State Univ. of Oil and Gas, Moscow (Russian Federation); Strizhakova, Yu. [Samara State Univ. (Russian Federation)

    2012-07-01

    Nowadays, the problem of complex usage of solid fossil fuels as raw materials for obtaining of motor fuels and chemical products is becoming increasingly important. A one of possible solutions of the problem is their gasification with further processing of gaseous and liquid products. In this work we have investigated the process of thermal and catalytic gasification of Baltic and Kashpir oil-shales. We have shown that, as compared with non-catalytic process, using of nickel catalyst in the reaction increases the yield of gas, as well as hydrogen content in it, and decreases the amount of liquid products. (orig.)

  13. Heterogeneous Catalytic Ozonization of Sulfosalicylic Acid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper describes the potential of heterogeneous catalytic ozonization of sulfo-salicylic acid (SSal). It was found that catalytic ozonization in the presence of Mn-Zr-O (a modified manganese dioxide supported on silica gel) had significantly enhanced the removal rate (72%) of total organic carbon (TOC) compared with that of ozonization alone (19%). The efficient removal rate of TOC was probably due to increasing the adsorption ability of catalyst and accelerating decomposition of ozone to produce more powerful oxidants than ozone.

  14. An Evaluation of the Vapor Phase Catalytic Ammonia Removal Process for Use in a Mars Transit Vehicle

    Science.gov (United States)

    Flynn, Michael; Borchers, Bruce

    1998-01-01

    An experimental program has been developed to evaluate the potential of the Vapor Phase Catalytic Ammonia Reduction (VPCAR) technology for use as a Mars Transit Vehicle water purification system. Design modifications which will be required to ensure proper operation of the VPCAR system in reduced gravity are also evaluated. The VPCAR system is an integrated wastewater treatment technology that combines a distillation process with high temperature catalytic oxidation. The distillation portion of the system utilizes a vapor compression distillation process to provide an energy efficient phase change separation. This portion of the system removes any inorganic salts and large molecular weight, organic contaminates, i.e., non-volatile, from the product water stream and concentrates these contaminates into a byproduct stream. To oxidize the volatile organic compounds and ammonia, a vapor phase, high temperature catalytic oxidizer is used. This catalytic system converts these compounds along with the aqueous product into CO2, H2O, and N2O. A secondary catalytic bed can then be used to reduce the N2O to nitrogen and oxygen (although not evaluated in this study). This paper describes the design specification of the VPCAR process, the relative benefits of its utilization in a Mars Transit Vehicle, and the design modification which will be required to ensure its proper operation in reduced gravity. In addition, the results of an experimental evaluation of the processors is presented. This evaluation presents the processors performance based upon product water purity, water recovery rates, and power.

  15. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Penate, I. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Julcour-Lebigue, C., E-mail: carine.julcour@ensiacet.fr [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Jauregui-Haza, U.J. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Habana (Cuba); Wilhelm, A.M.; Delmas, H. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Three activated carbons (AC) compared as adsorbents and oxidation catalysts. Black-Right-Pointing-Pointer Similar evolution for catalytic and adsorptive properties of AC over reuses. Black-Right-Pointing-Pointer Acidic and mesoporous AC to be preferred, despite lower initial efficiency. Black-Right-Pointing-Pointer Oxidative degradation of paracetamol improves biodegradability. Black-Right-Pointing-Pointer Convenient hybrid adsorption-regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  16. Diesel NO{sub x} catalytic converter development: A review

    Energy Technology Data Exchange (ETDEWEB)

    Heimrich, M.J. [Southwest Research Inst., San Antonio, TX (United States)

    1996-07-01

    This paper summarizes the findings of several technical articles on diesel NO{sub x} catalytic converter technology. Simplified theoretical reactions for NO{sub x} removal are discussed. Currently, development of catalytic NO{sub x} control technology for diesel engines is focused on systems that incorporate fuel hydrocarbons as the chemical reducing agent. Copper- and zeolite-based catalysts have been the predominant systems studied to date, but now catalysts containing precious metals are being investigated. Observed NO{sub x} reduction efficiencies typically ranged from 10 to 30 percent on actual engine exhaust systems when exhaust hydrocarbon enrichment strategies were used. Effects of carbon monoxide, sulfur dioxide, and water on NO{sub x} reduction efficiencies are reviewed. Recommendations for future research include attempts to broaden the temperature range of efficient NO{sub x} reduction, improving hydrocarbon selectivity toward the NO{sub x} reduction reaction, and the development of a supplementary reductant delivery system suitable for transient diesel engine operation.

  17. Novel Metal Nanomaterials and Their Catalytic Applications

    Directory of Open Access Journals (Sweden)

    Jiaqing Wang

    2015-09-01

    Full Text Available In the rapidly developing areas of nanotechnology, nano-scale materials as heterogeneous catalysts in the synthesis of organic molecules have gotten more and more attention. In this review, we will summarize the synthesis of several new types of noble metal nanostructures (FePt@Cu nanowires, Pt@Fe2O3 nanowires and bimetallic Pt@Ir nanocomplexes; Pt-Au heterostructures, Au-Pt bimetallic nanocomplexes and Pt/Pd bimetallic nanodendrites; Au nanowires, CuO@Ag nanowires and a series of Pd nanocatalysts and their new catalytic applications in our group, to establish heterogeneous catalytic system in “green” environments. Further study shows that these materials have a higher catalytic activity and selectivity than previously reported nanocrystal catalysts in organic reactions, or show a superior electro-catalytic activity for the oxidation of methanol. The whole process might have a great impact to resolve the energy crisis and the environmental crisis that were caused by traditional chemical engineering. Furthermore, we hope that this article will provide a reference point for the noble metal nanomaterials’ development that leads to new opportunities in nanocatalysis.

  18. Catalytic site interactions in yeast OMP synthase

    DEFF Research Database (Denmark)

    Hansen, Michael Riis; Barr, Eric W.; Jensen, Kaj Frank;

    2014-01-01

    45 (2006) 5330-5342]. This behavior was investigated in the yeast enzyme by mutations in the conserved catalytic loop and 5-phosphoribosyl-1-diphosphate (PRPP) binding motif. Although the reaction is mechanistically sequential, the wild-type (WT) enzyme shows parallel lines in double reciprocal...

  19. Lignin Valorization using Heterogenous Catalytic Oxidation

    DEFF Research Database (Denmark)

    Melián Rodríguez, Mayra; Shunmugavel, Saravanamurugan; Kegnæs, Søren;

    is complex so different model compounds are often used to study lignin valorization. These model compounds contain the linkages present in lignin, simplifying catalytic analysis and present analytical challenges related to the study of the complicated lignin polymer and the plethora of products that could...

  20. Performance characterization of a hydrogen catalytic heater.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry Alan; Kanouff, Michael P.

    2010-04-01

    This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.

  1. Electrochemical Promotion of Catalytic Reactions Using

    DEFF Research Database (Denmark)

    Petrushina, Irina; Bjerrum, Niels; Cleemann, Lars Nilausen;

    2007-01-01

    This paper presents the results of a study on electrochemical promotion (EP) of catalytic reactions using Pt/C/polybenzimidazole(H3PO4)/Pt/C fuel cell performed by the Energy and Materials Science Group (Technical University of Denmark) during the last 6 years[1-4]. The development of our...

  2. Toward Facilitative Mentoring and Catalytic Interventions

    Science.gov (United States)

    Smith, Melissa K.; Lewis, Marilyn

    2015-01-01

    In TESOL teacher mentoring, giving advice can be conceptualized as a continuum, ranging from directive to facilitative feedback. The goal, over time, is to lead toward the facilitative end of the continuum and specifically to catalytic interventions that encourage self-reflection and autonomous learning. This study begins by examining research on…

  3. Catalytic treatment of diesel engines, NOx emissions

    International Nuclear Information System (INIS)

    Some aspects of the operation of diesel engines are revised together with the pollutant emissions they produce, as well as the available catalytic technologies for the treatment of diesel emissions. Furthermore the performance of a catalyst developed in the environmental catalysis group for NOx reduction using synthetic gas mixtures simulating the emissions from diesel engines is presented

  4. Catalytic Converters Maintain Air Quality in Mines

    Science.gov (United States)

    2014-01-01

    At Langley Research Center, engineers developed a tin-oxide based washcoat to prevent oxygen buildup in carbon dioxide lasers used to detect wind shears. Airflow Catalyst Systems Inc. of Rochester, New York, licensed the technology and then adapted the washcoat for use as a catalytic converter to treat the exhaust from diesel mining equipment.

  5. Rapid Deployment of Rich Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Richard S. Tuthill

    2004-06-10

    The overall objective of this research under the Turbines Program is the deployment of fuel flexible rich catalytic combustion technology into high-pressure ratio industrial gas turbines. The resulting combustion systems will provide fuel flexibility for gas turbines to burn coal derived synthesis gas or natural gas and achieve NO{sub x} emissions of 2 ppmvd or less (at 15 percent O{sub 2}), cost effectively. This advance will signify a major step towards environmentally friendly electric power generation and coal-based energy independence for the United States. Under Phase 1 of the Program, Pratt & Whitney (P&W) performed a system integration study of rich catalytic combustion in a small high-pressure ratio industrial gas turbine with a silo combustion system that is easily scalable to a larger multi-chamber gas turbine system. An implementation plan for this technology also was studied. The principal achievement of the Phase 1 effort was the sizing of the catalytic module in a manner which allowed a single reactor (rather than multiple reactors) to be used by the combustion system, a conclusion regarding the amount of air that should be allocated to the reaction zone to achieve low emissions, definition of a combustion staging strategy to achieve low emissions, and mechanical integration of a Ceramic Matrix Composite (CMC) combustor liner with the catalytic module.

  6. Catalytic dehydrogenations of ethylbenzene to styrene

    NARCIS (Netherlands)

    Nederlof, C.

    2012-01-01

    This research work on the catalytic dehydrogenation of ethylbenzene (EB) to styrene (ST) had a primary goal of developing improved catalysts for dehydrogenation processes both in CO2 as well as with O2 that can compete with the conventional dehydrogenation process in steam. In order to achieve this

  7. Shungite carbon catalytic effect on coal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Grigorieva, E.N.; Rozhkova, N.N. [Russian Academy of Sciences, Moscow (Russian Federation). Institute for High Temperature

    1999-07-01

    The catalytic ability of shungite carbon in reactions of coal organic matter models appeared to be due to its fullerene structure only. Transition metal sulphides present in shungite carbon are not active in the conditions of coal treatment. Shungite carbon was shown to exhibit an acceleration of thermolysis of coal and organic matter models, mainly dehydrogenation. 5 refs., 1 tabs.

  8. Toward a catalytic site in DNA

    DEFF Research Database (Denmark)

    Jakobsen, Ulla; Rohr, Katja; Vogel, Stefan

    2007-01-01

    A number of functionalized polyaza crown ether building blocks have been incorporated into DNA-conjugates as catalytic Cu(2+) binding sites. The effect of the DNA-conjugate catalyst on the stereochemical outcome of a Cu(2+)-catalyzed Diels-Alder reaction will be presented....

  9. Catalytic asymmetric synthesis of mycocerosic acid

    NARCIS (Netherlands)

    ter Horst, B.; Feringa, B.L.; J. Minnaard, A.

    2007-01-01

    The first catalytic asymmetric total synthesis of mycocerosic acid was achieved via the application of iterative enantioselective 1,4-addition reactions and allows for the efficient construction of 1,3-polymethyl arrays with full stereocontrol; further exemplified by the synthesis of tetramethyl-dec

  10. SELECTIVE CATALYTIC REDUCTION MERCURY FIELD SAMPLING PROJECT

    Science.gov (United States)

    A lack of data still exists as to the effect of selective catalytic reduction (SCR), selective noncatalytic reduction (SNCR), and flue gas conditioning on the speciation and removal of mercury (Hg) at power plants. This project investigates the impact that SCR, SNCR, and flue gas...

  11. Catalytic conversion of biomass to bio-syncrude oil

    Energy Technology Data Exchange (ETDEWEB)

    Mante, Ofei Daku [Virginia Polytechnic Institute and State University, Biological Systems Engineering, Blacksburg, VA (United States); Agblevor, Foster A. [Utah State University, Biological Engineering, Logan, UT (United States)

    2011-12-15

    The conversion of biomass to transportation fuels and chemicals has been of immense interest in recent years. In this study, the production of high quality bio-oil (bio-syncrude oil) was achieved by catalytically cracking pyrolysis vapors from hybrid poplar in a dual-fluidized bed reactor. The catalytic deoxygenation of the primary pyrolysis vapors was achieved with a commercial HZSM-5 at 425-450 C. The organic, water, char, coke, and gas yields were 11.9, 20.9, 16.5, 3.8, and 46.8 wt.%, respectively. This work demonstrated that the use of a fluidized bed reactor for the catalytic upgrading reduces coke formation and increases catalyst lifetime. The concentration of the permanent gases was in the order of CO > CO{sub 2}> C{sub 3}H{sub 6}> CH{sub 4}> H{sub 2}> other C{sub 2}-C{sub 4}. The light bio-syncrude (LBS) oil collected from the condenser was predominately aromatic hydrocarbons. The heavy bio-syncrude (HBS) oil collected from the electrostatic precipitator consisted of mainly phenols, methyl-substituted phenols, naphthalenes, benzenediols, and naphthalenol. The bio-syncrude oils were low in oxygen, less viscous, less acidic, stable, and high in energy density. The higher heating value of the light and heavy bio-syncrude oil was 36.89 and 33.98 MJ/kg, respectively. The distillate yields from the atmospheric distillation showed that 91 wt.% of the LBS oil distills up to 220 C and 76 wt.% of the HBS oil distills up to 440 C. Accelerated stability test of the oils at 90 C for 24 h and storage of the oils at room temperature for 10 months showed that the bio-syncrude oils were stable. The catalytic deoxygenation of the pyrolysis vapors resulted in the removal of undesirable oxygenates such as levoglucosan, carboxylic acids, aldehydes, and ketones. The bio-syncrude oil can be considered as a suitable feed for use in a petroleum refinery for the production of transportation fuels and chemicals. (orig.)

  12. Plasma catalytic reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Bromberg, L.; Cohn, D.R.; Rabinovich, A. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Science and Fusion Center; Alexeev, N. [Russian Academy of Sciences, Moscow (Russian Federation). Baikov Inst. of Metallurgy

    1998-08-01

    Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels. This paper describes progress in plasma reforming experiments and calculations of high temperature conversion of methane using heterogeneous processes. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius) and high degree of dissociation and substantial degree of ionization. The high temperatures accelerate the reactions involved in the reforming process. Hydrogen-rich gas (50% H{sub 2}, 17% CO and 33% N{sub 2}, for partial oxidation/water shifting) can be efficiently made in compact plasma reformers. Experiments have been carried out in a small device (2--3 kW) and without the use of efficient heat regeneration. For partial oxidation/water shifting, it was determined that the specific energy consumption in the plasma reforming processes is 16 MJ/kg H{sub 2} with high conversion efficiencies. Larger plasmatrons, better reactor thermal insulation, efficient heat regeneration and improved plasma catalysis could also play a major role in specific energy consumption reduction and increasing the methane conversion. A system has been demonstrated for hydrogen production with low CO content ({approximately} 1.5%) with power densities of {approximately} 30 kW (H{sub 2} HHV)/liter of reactor, or {approximately} 10 m{sup 3}/hr H{sub 2} per liter of reactor. Power density should further increase with increased power and improved design.

  13. High-pressure catalytic reactions over single-crystal metal surfaces

    Science.gov (United States)

    Rodriguez, JoséA.; Wayne Goodman, D.

    1991-11-01

    Studies dealing with high-pressure catalytic reactions over single-crystal surfaces are reviewed. The coupling of an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh vacuum system for surface analysis allows detailed study of structure sensitivity, the effects of promoters and inhibitors on catalytic activity, and, in certain cases, identification of reaction intermediates by post-reaction surface analysis. Examples are provided which demonstrate the relevance of single-crystal studies for modeling the behaviour of high-surface-area supported catalysts. Studies of CO methanation and CO oxidation over single-crystal surfaces provide convincing evidence that these reactions are structure insensitive. For structure-sensitive reactions (ammonia synthesis, alkane hydrogenolysis, alkane isomerization, water-gas shift reaction, etc.) model single-crystal studies allow correlations to be established between surface structure and catalytic activity. The effects of both electronegative (S and P) and electropositive (alkali metals) impurities upon the catalytic activity of metal single crystals for ammonia synthesis, CO methanation, alkane hydrogenolysis, ethylene epoxidation and water-gas shift are discussed. The roles of "ensemble" and "ligand" effects in bimetallic catalysts are examined in light of data obtained using surfaces prepared by vapor-depositing one metal onto a crystal face of a dissimilar metal.

  14. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  15. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG; XiaoMing

    2001-01-01

    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

  16. 碳质材料催化臭氧氧化去除水中溶解性有机物的研究进展%Catalytic ozonation based on carbon materials for removing dissolved organic compounds from water:A review

    Institute of Scientific and Technical Information of China (English)

    钱飞跃; 王翻翻; 刘小朋; 李月寒; 王建芳

    2015-01-01

    Catalytic ozonation based on carbon materials labeled as CMs/O3 was well characterized by superior organics removal,high ozone utilization and without metal leaching;however,most of them were still at the stage of laboratory research,since a stable catalytic property of CMs could not be expected after a long running. In this paper,the main reaction mechanisms in CMs/O3 system for removing dissolved organics from water,both surface catalytic oxidation and hydroxyl radicals (HO·)oxidation in bulk solution were discussed and the influences of critical factors in heterogeneous reaction pathways and organics removal efficiency were elaborated. It was pointed out that the consumption of basic active sites and the accumulation of acid oxygen-containing groups on the surface were considered to cause a partial deactivation of CMs in cyclic experiments. In addition,using mesoporous catalyst,optimizing pH and normalized ozone dosage,could help in reducing internal mass transfer resistances,thus enhance target organics removal. This paper reviewed the recent advances of CMs/O3 applied in model organic pollutants removal and industrial wastewater treatment. Multi-walled carbon nanotube ( MWCNT ) and the innovative loading technology could improve CMs/O3 performances in deep purification of micro-polluted water body. Coupling mature treatment methods and CMs/O3 in an efficient and low-cost process was proposed as the important direction of further study.%碳质材料催化臭氧氧化(CMs/O3)体系具有除污性能强、臭氧利用率高和无金属溶出的特点,但受制于CMs催化性能的易失性,该方法目前仍处于实验室研发阶段。本文系统阐述了CMs/O3体系的反应原理,并认为表面催化氧化与均相羟自由基(HO·)反应是去除水中溶解性有机物的主要途径;详细分析了影响非均相反应机理与体系处理效能的关键因素,并指出在反应过程中,碳表面碱性活性点位的消耗与酸性

  17. Liquid-Phase Catalytic Hydrogenation of Furfural in Variable Solvent Media

    Institute of Scientific and Technical Information of China (English)

    夏淑倩; 李阳; 商巧燕; 张成武; 马沛生

    2016-01-01

    Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural was chosen as bio-oils model compound, and the catalytic hydrogenation of furfural over commercial 5%, Ru/C catalyst was firstly investigated in a series of gradient variable water/ethanol mixture solvents. Water had a signifi-cant effect on the distribution of product yields. The dominant reaction pathways varied with the water contents in the water/ethanol mixture solvents. Typically, when ethanol was used as the solvent, the main products were ob-tained by the hydrogenation of carbonyl group or furan ring. When pure water was used as the solvent, the rear-rangement reaction of furfural to cyclopentanone should be selectively promoted theoretically. However, serious polymerization and resinification were observed herein in catalytic hydrogenation system of pure water. The cata-lyst surface was modified by the water-insoluble polymers, and consequently, a relative low yield of cyclopenta-none was obtained. A plausible multiple competitive reaction mechanism between polymerization reaction and the hydrogenation of furfural was suggested in this study. Characterizations(TG,FT-IR,SEM)were employed to analyze and explain our experiments.

  18. Advances in solid-catalytic and non-catalytic technologies for biodiesel production

    International Nuclear Information System (INIS)

    Highlights: • The recent technologies for promoting biodiesel synthesis were elucidated. • The design of catalyst consideration of biodiesel production was proposed. • The recent advances and remaining difficulties in biodiesel synthesis were outlined. • The future research trend in biodiesel synthesis was highlighted. - Abstract: The insecure supply of fossil fuel coerces the scientific society to keep a vision to boost investments in the renewable energy sector. Among the many renewable fuels currently available around the world, biodiesel offers an immediate impact in our energy. In fact, a huge interest in related research indicates a promising future for the biodiesel technology. Heterogeneous catalyzed production of biodiesel has emerged as a preferred route as it is environmentally benign needs no water washing and product separation is much easier. The number of well-defined catalyst complexes that are able to catalyze transesterification reactions efficiently has been significantly expanded in recent years. The activity of catalysts, specifically in application to solid acid/base catalyst in transesterification reaction depends on their structure, strength of basicity/acidity, surface area as well as the stability of catalyst. There are various process intensification technologies based on the use of alternate energy sources such as ultrasound and microwave. The latest advances in research and development related to biodiesel production is represented by non-catalytic supercritical method and focussed exclusively on these processes as forthcoming transesterification processes. The latest developments in this field featuring highly active catalyst complexes are outlined in this review. The knowledge of more extensive research on advances in biofuels will allow a deeper insight into the mechanism of these technologies toward meeting the critical energy challenges in future

  19. Reforming of methane in tubes with a catalytic active wall

    International Nuclear Information System (INIS)

    The heterogeneous steam reforming process in tubes with catalytic active inner surface is studied. The purpose of this ivestigation is to find a method of predicting the reaction rate of the catalytic conversion of methane by steam. The dependency of the reaction rate upon the temperature, pressure, gas composition, Reynolds number, geometrical sizes of tubes and catalytic behaviour of the catalytic active inner wall of these tubes has been examined. It was found that the reaction rate mainly depends on the temperature. The reaction rate is limited by the catalytic behaviour and the heat resisting properties of the materials used. (author)

  20. Simulation of a fuel reforming system based on catalytic partial oxidation

    Science.gov (United States)

    Hohn, Keith L.; DuBois, Terry

    Catalytic partial oxidation (CPO) has potential for producing hydrogen that can be fed to a fuel cell for portable power generation. In order to be used for this purpose, catalytic partial oxidation must be combined with other processes, such as water-gas shift and preferential oxidation, to produce hydrogen with minimal carbon monoxide. This paper evaluates the use of catalytic partial oxidation in an integrated system for conversion of a military logistic fuel, JP-8, to high-purity hydrogen. A fuel processing system using CPO as the first processing step is simulated to understand the trade-offs involved in using CPO. The effects of water flow rate, CPO reactor temperature, carbon to oxygen ratio in the CPO reactor, temperature of preferential oxidation, oxygen to carbon ratio in the preferential oxidation reactor, and temperature for the water-gas shift reaction are evaluated. The possibility of recycling water from the fuel cell for use in fuel processing is evaluated. Finally, heat integration options are explored. A process efficiency, defined as the ratio of the lower heating value of hydrogen to that of JP-8, of around 53% is possible with a carbon to oxygen ratio of 0.7. Higher efficiencies are possible (up to 71%) when higher C/O ratios are used, provided that olefin production can be minimized in the CPO reactor.

  1. Method and apparatus for a catalytic firebox reactor

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Lance L. (North Haven, CT); Etemad, Shahrokh (Trumbull, CT); Ulkarim, Hasan (Hamden, CT); Castaldi, Marco J. (Bridgeport, CT); Pfefferle, William C. (Madison, CT)

    2001-01-01

    A catalytic firebox reactor employing an exothermic catalytic reaction channel and multiple cooling conduits for creating a partially reacted fuel/oxidant mixture. An oxidation catalyst is deposited on the walls forming the boundary between the multiple cooling conduits and the exothermic catalytic reaction channel, on the side of the walls facing the exothermic catalytic reaction channel. This configuration allows the oxidation catalyst to be backside cooled by any fluid passing through the cooling conduits. The heat of reaction is added to both the fluid in the exothermic catalytic reaction channel and the fluid passing through the cooling conduits. After discharge of the fluids from the exothermic catalytic reaction channel, the fluids mix to create a single combined flow. A further innovation in the reactor incorporates geometric changes in the exothermic catalytic reaction channel to provide streamwise variation of the velocity of the fluids in the reactor.

  2. From Catalytic Reaction Networks to Protocells

    Science.gov (United States)

    Kaneko, Kunihiko

    2013-12-01

    In spite of recent advances, there still remains a large gape between a set of chemical reactions and a biological cell. Here we discuss several theoretical efforts to fill in the gap. The topics cover (i) slow relaxation to equilibrium due to glassy behavior in catalytic reaction networks (ii) consistency between molecule replication and cell growth, as well as energy metabolism (iii) control of a system by minority molecules in mutually catalytic system, which work as a carrier of genetic information, and leading to evolvability (iv) generation of a compartmentalized structure as a cluster of molecules centered around the minority molecule, and division of the cluster accompanied by the replication of minority molecule (v) sequential, logical process over several states from concurrent reaction dynamics, by taking advantage of discreteness in molecule number.

  3. Janus droplet as a catalytic micromotor

    CERN Document Server

    Shklyaev, Sergey

    2015-01-01

    Self-propulsion of a Janus droplet in a solution of surfactant, which reacts on a half of a drop surface, is studied theoretically. The droplet acts as a catalytic motor creating a concentration gradient, which generates its surface-tension-driven motion; the self-propulsion speed is rather high, $60\\; {\\rm \\mu m/s}$ and more. This catalytic motor has several advantages over other micromotors: simple manufacturing, easily attained neutral buoyancy. In contrast to a single-fluid droplet, which demonstrates a self-propulsion as a result of symmetry breaking instability, for Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers. The paper was finalized and submitted by Denis S. Goldobin after Sergey Sklyaev had sadly passed away on June 2, 2014.

  4. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Molten Metal Technology was awarded a contract to demonstrate the applicability of the Catalytic Extraction Process, a proprietary process that could be applied to US DOE's inventory of low level mixed waste. This paper is a description of that technology, and included within this document are discussions of: (1) Program objectives, (2) Overall technology review, (3) Organic feed conversion to synthetic gas, (4) Metal, halogen, and transuranic recovery, (5) Demonstrations, (6) Design of the prototype facility, and (7) Results

  5. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  6. Ubiquitous "glassy" relaxation in catalytic reaction networks

    OpenAIRE

    Awazu, Akinori; Kaneko, Kunihiko

    2009-01-01

    Study of reversible catalytic reaction networks is important not only as an issue for chemical thermodynamics but also for protocells. From extensive numerical simulations and theoretical analysis, slow relaxation dynamics to sustain nonequlibrium states are commonly observed. These dynamics show two types of salient behaviors that are reminiscent of glassy behavior: slow relaxation along with the logarithmic time dependence of the correlation function and the emergence of plateaus in the rel...

  7. Thermal and catalytic pyrolysis of plastic waste

    OpenAIRE

    Débora Almeida; Maria de Fátima Marques

    2016-01-01

    Abstract The amount of plastic waste is growing every year and with that comes an environmental concern regarding this problem. Pyrolysis as a tertiary recycling process is presented as a solution. Pyrolysis can be thermal or catalytical and can be performed under different experimental conditions. These conditions affect the type and amount of product obtained. With the pyrolysis process, products can be obtained with high added value, such as fuel oils and feedstock for new products. Zeolit...

  8. Selective Catalytic Reduction of NO with Methane

    Institute of Scientific and Technical Information of China (English)

    Xiang Gao; Qi Yu; Limin Chen

    2003-01-01

    The removal of nitrogen oxides from exhaust gases has attracted great attention in recent years, and many approaches have been developed depending on the application. Methane, the main component of natural gas, has great potential as a NO reductant. In this paper, a number of catalysts previous reported for this catalytic reduction of NO have been reviewed, including a direct comparison of the relative activities and effective factors of the catalysts. Reaction mechanisms have also been explored preliminarily.

  9. Catalytic fast pyrolysis of lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  10. Materials for High-Temperature Catalytic Combustion

    OpenAIRE

    Ersson, Anders

    2003-01-01

    Catalytic combustion is an environmentally friendlytechnique to combust fuels in e.g. gas turbines. Introducing acatalyst into the combustion chamber of a gas turbine allowscombustion outside the normal flammability limits. Hence, theadiabatic flame temperature may be lowered below the thresholdtemperature for thermal NOXformation while maintaining a stable combustion.However, several challenges are connected to the application ofcatalytic combustion in gas turbines. The first part of thisthe...

  11. Control of a catalytic fluid cracker

    Energy Technology Data Exchange (ETDEWEB)

    Arbel, A.; Huang, Z.; Rinard, I.; Shinnar, R.

    1993-12-13

    Control offers an important tool for savings in refineries, mainly by integration of process models into on-line control. This paper is part of a research effort to better understand problems of partial control; control of a Fluid Catalytic Cracker (FCC) is used as example. Goal is to understand better the control problems of an FCC in context of model based control of a refinery, and to understand the general problem of designing partial control systems.

  12. Probing catalytic rate enhancement during intramembrane proteolysis.

    Science.gov (United States)

    Arutyunova, Elena; Smithers, Cameron C; Corradi, Valentina; Espiritu, Adam C; Young, Howard S; Tieleman, D Peter; Lemieux, M Joanne

    2016-09-01

    Rhomboids are ubiquitous intramembrane serine proteases involved in various signaling pathways. While the high-resolution structures of the Escherichia coli rhomboid GlpG with various inhibitors revealed an active site comprised of a serine-histidine dyad and an extensive oxyanion hole, the molecular details of rhomboid catalysis were unclear because substrates are unknown for most of the family members. Here we used the only known physiological pair of AarA rhomboid with its psTatA substrate to decipher the contribution of catalytically important residues to the reaction rate enhancement. An MD-refined homology model of AarA was used to identify residues important for catalysis. We demonstrated that the AarA active site geometry is strict and intolerant to alterations. We probed the roles of H83 and N87 oxyanion hole residues and determined that substitution of H83 either abolished AarA activity or reduced the transition state stabilization energy (ΔΔG‡) by 3.1 kcal/mol; substitution of N87 decreased ΔΔG‡ by 1.6-3.9 kcal/mol. Substitution M154, a residue conserved in most rhomboids that stabilizes the catalytic general base, to tyrosine, provided insight into the mechanism of nucleophile generation for the catalytic dyad. This study provides a quantitative evaluation of the role of several residues important for hydrolytic efficiency and oxyanion stabilization during intramembrane proteolysis. PMID:27071148

  13. Catalytic applications of bio-inspired nanomaterials

    Science.gov (United States)

    Pacardo, Dennis Kien Balaong

    The biomimetic synthesis of Pd nanoparticles was presented using the Pd4 peptide, TSNAVHPTLRHL, isolated from combinatorial phage display library. Using this approach, nearly monodisperse and spherical Pd nanoparticles were generated with an average diameter of 1.9 +/- 0.4 nm. The peptide-based nanocatalyst were employed in the Stille coupling reaction under energy-efficient and environmentally friendly reaction conditions of aqueous solvent, room temperature and very low catalyst loading. To this end, the Pd nanocatalyst generated high turnover frequency (TOF) value and quantitative yields using ≥ 0.005 mol% Pd as well as catalytic activities with different aryl halides containing electron-withdrawing and electron-donating groups. The Pd4-capped Pd nanoparticles followed the atom-leaching mechanism and were found to be selective with respect to substrate identity. On the other hand, the naturally-occurring R5 peptide (SSKKSGSYSGSKGSKRRIL) was employed in the synthesis of biotemplated Pd nanomaterials which showed morphological changes as a function of Pd:peptide ratio. TOF analysis for hydrogenation of olefinic alcohols showed similar catalytic activity regardless of nanomorphology. Determination of catalytic properties of these bio-inspired nanomaterials are important as they serve as model system for alternative green catalyst with applications in industrially important transformations.

  14. ZEOLITES: EFFECTIVE WATER PURIFIERS

    Science.gov (United States)

    Zeolites are known for their adsorption, ion exchange and catalytic properties. Various natural zeolites are used as odor and moisture adsorbents and water softeners. Due to their acidic nature, synthetic zeolites are commonly employed as solid acid catalysts in petrochemical ind...

  15. 水相生物油选择性加氢-催化裂解制取烯烃和芳香烃的试验研究%Experimental Research on Selective Hydrogenation-Catalytic Pyrolysis of Water-Soluble Bio-Oil to Produce Olefins and Aromatics

    Institute of Scientific and Technical Information of China (English)

    张会岩; 肖睿; GeorgeWHuber

    2012-01-01

    本文在气相流动反应器中采用ZSM-5催化剂对水相选择性加氢生物油进行了催化裂解试验研究。主要考察了反应温度、质量空速、油分压和原料油组分含量对产物产率和选择性的影响。结果表明,选择性加氢生物油转化为石油化工用品(烯烃和芳香烃)的最优工况为:反应温度,600°C;质量空速,11.7h-1;油分压,6693Pa;油组分含量,12.5%。在此工况下,石油化工用品达到最高碳产率76.0%,其中烯烃57.6%,芳香烃18.4%。烯烃和芳香烃的产率及其主要成分的选择性可以根据市场的需求通过调节反应条件来改变。%Catalytic pyrolysis of selectively hydrogenated water-soluble bio-oil was carried out in a gas flow reactor with ZSM-5 catalyst. The effect of temperature, weight hourly space velocity, oil partial pressure in gas phase and oil content in the feed on product yields and selectivities were studied. The results show that the optimizing conditions for petrochemicals (olefins and aromatics) production were: temperature, 600~C; WHSV, 11.7 h-1, oil partial pressure, 6693 Pa; oil content, 12.5%. The maximum yield of petrochemicals is 76.0%, including 57.6% olefins and 18.4% aromatics. The olefins and aromatics yields and their main components selectivities can be adjusted by changing the reaction conditions according to market requirements.

  16. Co-Mn-Al层状双氢氧化物催化臭氧氧化水中有机污染物的活性%Catalytic Performance of Layered Double Hydroxides Co-Mn-Al for Ozonation of Organic Pollutants in Water

    Institute of Scientific and Technical Information of China (English)

    隋铭皓; 段标标; 盛力; 黄书杭; 佘磊

    2012-01-01

    采用共沉淀法制备了Co-Mn-Al层状双氢氧化物,并将其用于以硝基苯为目标污染物的催化臭氧降解反应中.结果表明,Co-Mn-Al层状双氢氧化物存在时,硝基苯的降解和矿化效率较单独臭氧氧化系统显著提高.采用加入羟基自由基捕获剂(叔丁醇)和电子顺磁共振检测(5,5-二甲基-1-吡咯啉-N-氧化物为捕获剂)的间接、直接方法,探讨了Co-Mn-Al层状双氢氧化物是否强化了羟基自由基的生成.结果表明,加入叔丁醇降低了硝基苯的降解效率;电子顺磁共振检出了更强的羟基自由基加成物生成信号.Co-Mn-Al层状双氢氧化物的存在促进了羟基自由基的生成.%The catalytic activity of layered double hydroxides containing Co,Mn,and Al for the ozonation of organic pollutants in water was investigated.The Co-Mn-Al layered double hydroxides were prepared by coprecipitation.Nitrobenzene was used as a model compound,and it was shown that the degradation and mineralization of nitrobenzene was increased by the presence of Co-Mn-Al layered double hydroxides as compared to ozonation alone.Both an indirect method of adding a scavenger (tert-butanol) of the hydroxyl radical chain reaction and direct electron spin resonance using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trapping agent were used to investigate the generation of hydroxyl radicals in the ozonation by the Co-Mn-A1layered double hydroxides.The inhibiting effect of tert-butanol on the degradation of nitrobenzene and the detection of the stronger 5,5-dimethyl-1-pyrroline-N-oxide/hydroxyl radical adduct showed that the Co-Mn-Al layered double hydroxides catalyzed the generation of hydroxyl radicals.

  17. Incorporation of catalytic dehydrogenation into fischer-tropsch synthesis to significantly reduce carbon dioxide emissions

    Energy Technology Data Exchange (ETDEWEB)

    Huffman, Gerald P.

    2012-11-13

    A new method of producing liquid transportation fuels from coal and other hydrocarbons that significantly reduces carbon dioxide emissions by combining Fischer-Tropsch synthesis with catalytic dehydrogenation is claimed. Catalytic dehydrogenation (CDH) of the gaseous products (C1-C4) of Fischer-Tropsch synthesis (FTS) can produce large quantities of hydrogen while converting the carbon to multi-walled carbon nanotubes (MWCNT). Incorporation of CDH into a FTS-CDH plant converting coal to liquid fuels can eliminate all or most of the CO.sub.2 emissions from the water-gas shift (WGS) reaction that is currently used to elevate the H.sub.2 level of coal-derived syngas for FTS. Additionally, the FTS-CDH process saves large amounts of water used by the WGS reaction and produces a valuable by-product, MWCNT.

  18. Fuzzy logic for burner, solar boiler and catalytic converter; Brander, zonneboiler en katalysator vaag geregeld

    Energy Technology Data Exchange (ETDEWEB)

    Voorter, P.H.C.

    1995-05-01

    The application of fuzzy logic in the process control of a cement furnace at a Dutch cement industry (Enci in Maastricht) proved to be successful: the production increased by 4% and the energy consumption was reduced by 3% per ton product. Fuzzy logic can also be used in smaller energy equipment. Applications in a burner of a central heating boiler, a solar water heater and a catalytic converter in a motorcycle are discussed. 5 figs., 1 tab., 2 refs.

  19. Catalytic dechlorination of diclofenac by biogenic palladium in a microbial electrolysis cell

    OpenAIRE

    De Gusseme, Bart; Soetaert, Maarten; Hennebel, Tom; Vanhaecke, Lynn; Boon, Nico; Verstraete, Willy

    2012-01-01

    Summary Diclofenac is one of the most commonly detected pharmaceuticals in wastewater treatment plant (WWTP) effluents and the receiving water bodies. In this study, biogenic Pd nanoparticles (‘bio‐Pd’) were successfully applied in a microbial electrolysis cell (MEC) for the catalytic reduction of diclofenac. Hydrogen gas was produced in the cathodic compartment, and consumed as a hydrogen donor by the bio‐Pd on the graphite electrodes. In this way, complete dechlorination of 1 mg diclofenac ...

  20. Magnetic carbon xerogels for the catalytic wet peroxide oxidation of 4-nitrophenol solutions

    OpenAIRE

    Ribeiro, R; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2015-01-01

    Catalytic wet peroxide oxidation (CWPO) is a well-known advanced oxidation process for the removal of organic pollutants from industrial process waters and wastewater. Specifically, CWPO employs hydrogen peroxide (H2O2) as oxidation source and a suitable catalyst to promote its decomposition via formation of hydroxyl radicals (HO•), which exhibit high oxidizing potential and serve as effective species in the destruction of a huge range of organic pollutants

  1. Modeling the Catalysis of Anti-Cocaine Catalytic Antibody: Competing Reaction Pathways and Free Energy Barriers

    OpenAIRE

    Pan, Yongmei; Gao, Daquan; Zhan, Chang-Guo

    2008-01-01

    The competing reaction pathways and the corresponding free energy barriers for cocaine hydrolysis catalyzed by an anti-cocaine catalytic antibody, mAb 15A10, were studied by using a novel computational strategy based on the binding free energy calculations on the antibody binding with cocaine and transition states. The calculated binding free energies were used to evaluate the free energy barrier shift from the cocaine hydrolysis in water to the antibody-catalyzed cocaine hydrolysis for each ...

  2. Catalytic Combustion of Ethyl Acetate over Nanostructure Cobalt Supported ZSM-5 Zeolite Catalysts

    Institute of Scientific and Technical Information of China (English)

    NIAEI,Aligholi; SALARI,Dariush; HOSSEINI,Seyed Ali; KHATAMIAN,Masumeh; JODAEL,Azadeh

    2009-01-01

    Gas phase catalytic combustion of ethyl acetate,as one of volatile organic compounds(VOC),was studied on nanostructure ZSM-5.HZSM-5 and Co-ZSM-5 with different cobalt loadings. Nanostructure of ZSM-5 Was deter-mined by XRD,SEM and TEM. Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor.Results showed that the Co-ZSM-5 catalysts had better activity than others and at temperatures below 350℃.amount of Co loading was mole effective on catalytic activity.The order of conversion of ethyl acetate over differ-ent Co loading is as follows:Co-ZSM-5(0.75 wt%)catalytic oxidation conditions has not so large influence on conversion. Furthermore,the presence of water vapor in inlet gaseous feed has an inhibitive effect on ethyl acetate conversion and at the temperatures above 400℃,the effect decreases.

  3. Surface Structure and Catalytic Performance of Ni-Fe Catalyst for Low-Temperature CO Hydrogenation

    Directory of Open Access Journals (Sweden)

    Fanhui Meng

    2014-01-01

    Full Text Available Catalysts 16NixFe/Al2O3 (x is 0, 1, 2, 4, 6, 8 were prepared by incipient wetness impregnation method and the catalytic performance for the production of synthetic natural gas (SNG from CO hydrogenation in slurry-bed reactor were studied. The catalysts were characterized by BET, XRD, UV-Vis DRS, H2-TPR, CO-TPD, and XPS, and the results showed that the introduction of iron improved the dispersion of Ni species, weakened the interaction between Ni species and support and decreased the reduction temperature and that catalyst formed Ni-Fe alloy when the content of iron exceeded 2%. Experimental results revealed that the addition of iron to the catalyst can effectively improve the catalytic performance of low-temperature CO methanation. Catalyst 16Ni4Fe/Al2O3 with the iron content of 4% exhibited the best catalytic performance, the conversion of CO and the yield of CH4 reached 97.2% and 84.9%, respectively, and the high catalytic performance of Ni-Fe catalyst was related to the property of formed Ni-Fe alloy. Further increase of iron content led to enhancing the water gas shift reaction.

  4. Clinical analysis of anticoagulation for acute exacerbation of chronic obstructive pulmonary disease with co-existing suspected acute pulmonary embolism%慢性阻塞性肺疾病急性加重疑诊合并肺栓塞的抗凝治疗临床分析

    Institute of Scientific and Technical Information of China (English)

    张琪琳; 虞仲英; 张舒; 肖中; 蔡峰

    2008-01-01

    Objective To investigate the efficacy and safety of the anticoagulation for acute exacerbation of chronic obstructive pulmonary disease(AECOPD)with co-existing suspected acute pulmonary embolistn(PE).Methods Thirty-seven severe AECOPD inpatients with a positive D-dimer assay were divided into A group(a value of PaO2 was normal)and B group(hypoxia).The two groups were randomlv redistributed into anticoagulation subgroups(A1 and B1)and non-anticoagulation subgroups(A2 and B2).The consequences of the management were surveyed and assessed.Results Bi subgroup versus B2 subgrouP:there were significant differences in dyspnea,PaO2,D-dimer and ventilating time(P0.05).B1 subgroup was preferable to B2 subgroup.Conclusions Anticoagulation should immediately be given to patients with severe AECOPD who do not require further investigation of CTPA or isotope lung scanning for confirming PE,providing the patients have risk factors for venous thromboembolism or high probability for PE,and a positive D-dimer test,and receiving mechanic ventilation,and existing hypoxia,even SO be given oxygen or received non-invasive mechanic ventilation,and acute left heart failure and pneumothorax were excluded.%目的 探讨对重度慢性阻塞性肺疾病急性加重(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)疑诊合并肺栓塞(PE)患者进行抗凝治疗的有效性和安全性.方法 将D-二聚体阳性的37例重度AECOPD患者分为血氧分压正常组(A组)和血氧分压降低组(B组),并对两组患者进一步随机分为抗凝(A1、B1)和非抗凝(A2、B2)两个亚组.分别观察和评估A组和B组抗凝和非抗凝治疗的临床变化.结果 B1,组和B2组比较:临床症状改善、动脉血气分析、D-二体和机械通气时间等比较差异有统计学意义(P<0.05),两组并发症比较差异无统计学意义(P>0.05),B1组优于B2组·结论具有静脉血栓栓塞高危因素或临床高度可疑PE、D-二体检测阳性的重度AECOPD机

  5. Turning goals into results: the power of catalytic mechanisms.

    Science.gov (United States)

    Collins, J

    1999-01-01

    Most executives have a big, hairy, audacious goal. They write vision statements, formalize procedures, and develop complicated incentive programs--all in pursuit of that goal. In other words, with the best of intentions, they install layers of stultifying bureaucracy. But it doesn't have to be that way. In this article, Jim Collins introduces the catalytic mechanism, a simple yet powerful managerial tool that helps translate lofty aspirations into concrete reality. Catalytic mechanisms are the crucial link between objectives and performance; they are a galvanizing, nonbureaucratic means to turn one into the other. What's the difference between catalytic mechanisms and most traditional managerial controls? Catalytic mechanisms share five characteristics. First, they produce desired results in unpredictable ways. Second, they distribute power for the benefit of the overall system, often to the discomfort of those who traditionally hold power. Third, catalytic mechanisms have teeth. Fourth, they eject "viruses"--those people who don't share the company's core values. Finally, they produce an ongoing effect. Catalytic mechanisms are just as effective for reaching individual goals as they are for corporate ones. To illustrate how catalytic mechanisms work, the author draws on examples of individuals and organizations that have relied on such mechanisms to achieve their goals. The same catalytic mechanism that works in one organization, however, will not necessarily work in another. Catalytic mechanisms must be tailored to specific goals and situations. To help readers get started, the author offers some general principles that support the process of building catalytic mechanisms effectively. PMID:10539210

  6. Heterogeneous catalytic materials solid state chemistry, surface chemistry and catalytic behaviour

    CERN Document Server

    Busca, Guido

    2014-01-01

    Heterogeneous Catalytic Materials discusses experimental methods and the latest developments in three areas of research: heterogeneous catalysis; surface chemistry; and the chemistry of catalysts. Catalytic materials are those solids that allow the chemical reaction to occur efficiently and cost-effectively. This book provides you with all necessary information to synthesize, characterize, and relate the properties of a catalyst to its behavior, enabling you to select the appropriate catalyst for the process and reactor system. Oxides (used both as catalysts and as supports for cata

  7. Influence of real-world environments on the motion of catalytic bubble-propelled micromotors.

    Science.gov (United States)

    Zhao, Guanjia; Wang, Hong; Khezri, Bahareh; Webster, Richard D; Pumera, Martin

    2013-08-01

    Self-propelled autonomous micromachines have recently been tasked to carry out various roles in real environments. In this study, we expose the microjets to various types of water that are present in the real world, examples include tap water, rain water, lake water and sea water, and we sought to investigate their behaviors under real world conditions. We observed that the viability and mobility of the catalytic bubble jet engines are strongly influenced by the type of environmental water sample. Amongst the four water samples tested, the seawater sample exhibits the strongest influence, completely disabling any motions arising from the microjets. The motion of the microjets is also reduced in tap water, which contains large quantities of inorganic ions that have been purposely introduced into tap water via processing in water treatment plants. Lake water and rain water samples exhibited the least influence on the microjet's motion. All of the four water samples were also characterized by determining their ion compositions and conductivities, and we will show that there is a distinct correlation between the reduced mobility of the microjets with the ion content of the water found in real environments.

  8. Effects of Reduced Sulfur Compounds on Pd-catalytic Hydrodechlorination of TCE in Groundwater by Cathodic H2 under Electrochemically-induced Oxidizing Conditions

    OpenAIRE

    Yuan, Songhu; Chen, Mingjie; Mao, Xuhui; Alshawabkeh, Akram N.

    2013-01-01

    Reduced sulfur compounds (RSCs) poison Pd catalysts for catalytic hydrodechlorination of contaminants in anoxic groundwater. This study investigates the effects of RSCs on Pd-catalytic hydrodechlorination of trichloroethylene (TCE) in oxic groundwater. Water electrolysis in an undivided electrolytic cell is used to produce H2 for TCE hydrodechlorination under oxidizing conditions. TCE is efficiently hydrodechlorinated to ethane, with significant accumulation of H2O2 under acidic conditions. P...

  9. Session 4: Catalytic behavior of Ni(II)-Al hydrotalcite like compounds in bio-ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Comas, J.; Laborde, M.; Amadeo, N. [Laboratorio de Procesos Cataliticos, Dpto. Ingenieria Quimica, Facultad de Ingenieria. Pabellon de Industrias. Ciudad Universitaria (1428) Buenos Aires (Argentina)

    2004-07-01

    In this work, the ethanol steam reforming on massive Ni(II)-Al hydrotalcite like compounds as catalyst, at 773 K and atmospheric pressure, was studied. In particular, from the experiments carried out at different water/ethanol feed ratio is possible to elucidate the catalytic behavior for ethanol steam reforming over Ni(II)-Al hydrotalcite. (authors)

  10. Substrate binding and catalytic mechanism in phospholipase C from Bacillus cereus. a molecular mechanics and molecular dynamics study

    DEFF Research Database (Denmark)

    da Graça Thrige, D; Buur, J R; Jørgensen, Flemming Steen

    1997-01-01

    For the first time a consistent catalytic mechanism of phospholipase C from Bacillus cereus is reported based on molecular mechanics calculations. We have identified the position of the nucleophilic water molecule, which is directly involved in the hydrolysis of the natural substrate phosphatidyl...

  11. The tritium labeling of Butibufen by heterogeneous catalytic exchange; Marcado del Butibufen con Tritio por inter- cambio catalitico en disolucion

    Energy Technology Data Exchange (ETDEWEB)

    Santamaria, J.; Rebollo, D.

    1986-07-01

    The labeling of a new non-steroidal antiinflammatory agent, Butibufen (2-(4-isobutylphenyl) butyric acid) was studied. The method used was heterogeneous catalytic exchange between Butibufen and tritiated water, obtained in situ. Purification was accomplished through thin layer chromatography. Concentration, purity and specific activity of the labeled drug were determined by ultraviolet and liquid scintillation techniques. (Author) 7 refs.

  12. Microwave-Irradiated Polyol Method Synthesis of Pt/C Catalysts and Its Catalytic Activities for Hydrogen-Water Liquid Exchange Reaction%Pt/C催化剂的高压微波法制备及氢同位素交换性能研究

    Institute of Scientific and Technical Information of China (English)

    侯京伟; 熊亮萍; 翁葵平; 胡胜; 罗阳明

    2012-01-01

    Pt/C catalysts with isopropanol as both dispersant and reducing agent were synthesized by microwave-irradiated polyol method. The microstructures of the catalysts were characterized by XRD and TEM. The effects of capping agents, pH and heating rate on Pt particle size were studied. Then Pt/C catalysts were loaded on foam nickel with polytetrafluoroethylene latex to obtain hydrophobic catalysts, and their catalytic activities for hydrogen-water liquid phase exchange reaction were investigated. The results show that compared to the non-capped Pt/C catalysts, the average size of Pt particles in sodium acetate, sodium glycollate and disodium hydrogen citrate capped Pt/C catalysts decreases from 4. 4 nm to 2. 3, 2. 5, and 2. 3 nm respectively, and the agglom-eration of Pt particles becomes obscure. The mean size of Pt particles in Pt/C catalysts decreases evidently with the increasing of the heating rate. However, the mean sizes of Pt particles in the Pt/C catalysts prepared with different pH of the synthesis solution are similar. The activity of the hydrophobic catalysts with capping agents is high for hydrogen-water liquid exchange reaction, and is enhanced by decreasing the average particle size, in the range of 2. 3-4. 4 nm.%以异丙醇为分散溶剂与还原剂,采用高压微波加热法制备了Pt/C催化剂,研究了不同实验条件对Pt尺寸的影响,利用XRD、TEM对催化剂进行了表征.再将Pt/C催化剂和聚四氟乙烯混合,负载至泡沫镍上得到疏水催化剂,研究其对氢-水液相催化交换反应的催化性能.结果表明:加入保护剂乙酸钠、羟基乙酸钠、柠檬酸氢二钠后,Pt/C催化剂的活性金属团聚现象减少,Pt平均尺寸明显减小(由4.4 nm分别降低到2.3、2.5、2.3 nm);升温速率对Pt尺寸影响较大,随着升温速率的提高,活性金属Pt的尺寸减小;而pH的变化对Pt粒子的尺寸影响较小.加入保护剂有利于氢-水交换反应的催化剂活性,Pt尺寸为2.3~4

  13. 一种水溶性氢氧根钌配合物的合成及其对乙腈的催化水化作用%Synthesis of a Water-Soluble Ruthenium Hydroxide Complex and Its Role in Catalytic Hydration of Acetonitrile

    Institute of Scientific and Technical Information of China (English)

    尹传奇; 刘珺; 柏正武

    2011-01-01

    以RuCl3·3H2O为原料合成了水溶性钌配合物[(bipy)2Ru(H2O)2](OTf)2(bipy=2,2'-bipyridine,Otf-=triflate),利用DBU(1,8-Diazabicyclo[5.4.0]undec-7-ene)脱质子化合成了水溶性氢氧根配合物[(bipy)2Ru(H2O)(OH)](OTf).研究了[(bipy)2Ru(H2O)(OH)](OTf)催化水化乙腈生成乙酰胺的反应.机理研究表明,催化循环的关键中间体为氧配位的酰亚胺配合物[(bipy)2Ru(CH3CN)(OCMe=NH)]+,经过生成[(bipy)2Ru(κ2-N,O-NH=CMeN=CMeO)]+、水亲核进攻开环生成{(bipy)2Ru[NH=C(OH)Me](OCMe=NH)}+、乙腈取代其NH=C(OH)Me配体产生乙酰胺,同时再生成[(bipy)2Ru-(CH3CN)(OCMe=NH)]+完成催化循环.%In the presence of DBU(1,8-Diazabicycloundec-7-ene),a novel water-soluble hydroxide ruthenium complex [(bipy)2Ru(H2O)(OH)](OTf) was synthesized by deprotonation of [(bipy)2Ru(H2O)2]-(OTf)2(bipy=2,2'-bipyridine,Otf-=triflate),which was prepared using RuCl3·3H2O as starting material.The hydration of acetonitrile to form acetamide catalyzed by [(bipy)2Ru(H2O)(OH)](OTf) was studied.O-bonded imido complex [(bipy)2Ru(N≡CCH3)(OCMe=NH)]+ is postulated to be the key intermediate,which then undergoes nucleophilic attack at the carbon atom of nitrile ligand to form [(bipy)2Ru(k2-N,ONH=CMeN=CMeO)]+.Ring-opening nucleophilic attack of [(bipy)2Ru(k2-N,O-NH=CMeN=CMeO)]+by water produces {(bipy)2Ru[NH=C(OH)Me](OCMe=NH)}+.The displacement of NH=C(OH)Me ligand in the latter complex by acetonitrile forms acetamide,and regenerates [(bipy)2Ru(N≡CCH3)-(OCMe=NH)]+ to fulfill catalytic cycle.

  14. Development of a water detritiation facility for JET

    Energy Technology Data Exchange (ETDEWEB)

    Perevezentsev, A.N. E-mail: alex.perevezentsev@jet.uk; Bell, A.C.; Brennan, P.D.; Hemmerich, J.L

    2002-11-01

    A water detritiation facility, based on a world-wide adopted combined electrolysis catalytic exchange (CECE) process, for the JET active gas handling plant is described. A research and development programme is presented. The programme includes the testing of structured inert packing with an incorporated hydrophobic catalyst for increased throughput of a liquid phase catalytic exchange (LPCE) column, a vapour phase catalytic exchange (VPCE) process for reduction of tritium inventory in the alkali electrolyser and a column of high effectiveness for alkali retention.

  15. Development of a water detritiation facility for JET

    International Nuclear Information System (INIS)

    A water detritiation facility, based on a world-wide adopted combined electrolysis catalytic exchange (CECE) process, for the JET active gas handling plant is described. A research and development programme is presented. The programme includes the testing of structured inert packing with an incorporated hydrophobic catalyst for increased throughput of a liquid phase catalytic exchange (LPCE) column, a vapour phase catalytic exchange (VPCE) process for reduction of tritium inventory in the alkali electrolyser and a column of high effectiveness for alkali retention

  16. Catalytic bioscavengers in nerve agent poisoning: A promising approach?

    Science.gov (United States)

    Worek, Franz; Thiermann, Horst; Wille, Timo

    2016-02-26

    The repeated use of the nerve agent sarin against civilians in Syria in 2013 emphasizes the continuing threat by chemical warfare agents. Multiple studies demonstrated a limited efficacy of standard atropine-oxime treatment in nerve agent poisoning and called for the development of alternative and more effective treatment strategies. A novel approach is the use of stoichiometric or catalytic bioscavengers for detoxification of nerve agents in the systemic circulation prior to distribution into target tissues. Recent progress in the design of enzyme mutants with reversed stereo selectivity resulting in improved catalytic activity and their use in in vivo studies supports the concept of catalytic bioscavengers. Yet, further research is necessary to improve the catalytic activity, substrate spectrum and in vivo biological stability of enzyme mutants. The pros and cons of catalytic bioscavengers will be discussed in detail and future requirements for the development of catalytic bioscavengers will be proposed.

  17. Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

    Science.gov (United States)

    Collins, Gillian; Holmes, Justin D

    2016-07-01

    Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs. PMID:26823380

  18. Catalytic Mechanism of Human Alpha-galactosidase

    Energy Technology Data Exchange (ETDEWEB)

    Guce, A.; Clark, N; Salgado, E; Ivanen, D; Kulinskaya, A; Brumer, H; Garman, S

    2010-01-01

    The enzyme {alpha}-galactosidase ({alpha}-GAL, also known as {alpha}-GAL A; E.C. 3.2.1.22) is responsible for the breakdown of {alpha}-galactosides in the lysosome. Defects in human {alpha}-GAL lead to the development of Fabry disease, a lysosomal storage disorder characterized by the buildup of {alpha}-galactosylated substrates in the tissues. {alpha}-GAL is an active target of clinical research: there are currently two treatment options for Fabry disease, recombinant enzyme replacement therapy (approved in the United States in 2003) and pharmacological chaperone therapy (currently in clinical trials). Previously, we have reported the structure of human {alpha}-GAL, which revealed the overall structure of the enzyme and established the locations of hundreds of mutations that lead to the development of Fabry disease. Here, we describe the catalytic mechanism of the enzyme derived from x-ray crystal structures of each of the four stages of the double displacement reaction mechanism. Use of a difluoro-{alpha}-galactopyranoside allowed trapping of a covalent intermediate. The ensemble of structures reveals distortion of the ligand into a {sup 1}S{sub 3} skew (or twist) boat conformation in the middle of the reaction cycle. The high resolution structures of each step in the catalytic cycle will allow for improved drug design efforts on {alpha}-GAL and other glycoside hydrolase family 27 enzymes by developing ligands that specifically target different states of the catalytic cycle. Additionally, the structures revealed a second ligand-binding site suitable for targeting by novel pharmacological chaperones.

  19. Conventional and catalytic pyrolysis of pinyon juniper biomass

    Science.gov (United States)

    Yathavan, Bhuvanesh Kumar

    Pinyon and juniper are invasive woody species in Western United States that occupy over 47 million acres of land. The US Bureau of Land Management (BLM) has embarked on harvesting these woody species to make room for range grasses for grazing. The major application of harvested pinyon-juniper (PJ) is low value firewood. Thus, there is a need to develop new high value products from this woody biomass to reduce the cost of harvesting. In this research PJ biomass was processed through pyrolysis technology to produce value added products. The first part of the thesis demonstrates the effect of PJ wood, bark and mixture biomass and temperature on the product yield and on the quality of the bio-oil produced. The second part focuses on the optimization of process parameters for maximum yield and the third part focuses on upgrading the bio-oil with an industrial catalyst (HZSM5) and an industrial waste product (red mud). The results obtained from the first part showed that PJ wood produced maximum bio-oil yield, followed by PJ mixture and bark. The bio-oil yield from PJ wood had low viscosity when compared to PJ mixture and PJ bark. The second part focused on studying the effect of process parameters (temperature, feed rate and the gas flow rate) on the total liquid, organic, water, char and gas yield. The results show that each response is affected by different factor level combinations, and maximum yield for each response was obtained at different factors level. The third part focused on catalytic pyrolysis of PJ biomass using both HZSM-5 catalyst and red mud. The mechanisms of catalysis by the two catalysts were quite different. Whereas the HZSM-5 rejected oxygen mostly as carbon monoxide and water and produced lower amounts of carbon dioxide, on the contrary the red mud produced more carbon dioxide and water and less carbon monoxide. The higher heating value of the red mud catalyzed oil (29.46 MJ/kg) was slightly higher than that catalyzed by HZSM-5 (28.55 MJ/kg). Thus

  20. A method for controlling catalytic reforming

    Energy Technology Data Exchange (ETDEWEB)

    Karamyshev, M.S.; Denilov, N.A.; Kamyshnikov, A.I.; Kirilin, Yu.A.; Lozinskiy, V.N.; Melman, A.Z.; Ovchinnikova, T.F.; Shpunt, M.I.; Shuvalov, V.V.; Zayashnikov, Ye.N.

    1983-01-01

    In the method for controlling the process of catalytic reforming, which includes mixing the raw material components with the production of a raw material, reforming and isolation of the final products, through changing the relationship of the expenditures of the raw material components relative to the content of the target components in the raw material, in order to support and stabilize an assigned production of the final products, the relationship of the expenditures of the raw material components are changed with correction based on the flow rates of the final products. A block diagram of the installation which realizes the proposed method is cited.

  1. Transport in a Microfluidic Catalytic Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, H G; Chung, J; Grigoropoulos, C P; Greif, R; Havstad, M; Morse, J D

    2003-04-30

    A study of the heat and mass transfer, flow, and thermodynamics of the reacting flow in a catalytic microreactor is presented. Methanol reforming is utilized in the fuel processing system driving a micro-scale proton exchange membrane fuel cell. Understanding the flow and thermal transport phenomena as well as the reaction mechanisms is essential for improving the efficiency of the reforming process as well as the quality of the processed fuel. Numerical studies have been carried out to characterize the transport in a silicon microfabricated reactor system. On the basis of these results, optimized conditions for fuel processing are determined.

  2. Submicron Polyethylene Particles from Catalytic Emulsion Polymerization

    OpenAIRE

    Bauers, Florian Martin; Thomann, Ralf; Mecking, Stefan

    2003-01-01

    Particles of linear polyethylene (Mn = (2-3)X 10000 g mol-1; Mw/Mn = 2-4) obtained by catalytic emulsion polymerization of ethylene possess a nonspherical, lentil-like shape with an average aspect ratio of ca. 10 and diameters from 30 to > 300 nm, as determined by TEM and AFM. The particle structure results from a stacking of the lamellae along the one shorter axis of the lentils (i.e., their height, by contrast to the diameter). In addition to these multilamellae particles, remarkably, a con...

  3. Temperature control of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-06-08

    In an ic engine having a catalytic convertor, the catalyst heater is controlled in dependence upon an estimate of the temperature of the catalyst so that there is no need for a sensor in the hostile environment of the exhaust. A valve indicative of the catalyst temperature is stored and modified in accordance with a model of the catalyst temperature. The model can be a mathematical mood carried out by a signal processor or an electrical model with the catalyst temperature being represented by the charge stored on a capacitor. (Author)

  4. Biomimetic, Catalytic Oxidation in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Shun-lchi Murahashi

    2005-01-01

    @@ 1Introduction Oxidation is one of the most fundamental reactions in organic synthesis. Owing to the current need to develop forward-looking technology that is environmentally acceptable with respect many aspects. The most attractive approaches are biomimetic oxidation reactions that are closely related to the metabolism of living things. The metabolisms are governed by a variety of enzymes such as cytochrome P-450 and flavoenzyme.Simulation of the function of these enzymes with simple transition metal complex catalyst or organic catalysts led to the discovery of biomimetic, catalytic oxidations with peroxides[1]. We extended such biomimetic methods to the oxidation with molecular oxygen under mild conditions.

  5. Tritium stripping by a catalytic exchange stripper

    International Nuclear Information System (INIS)

    A catalytic exchange process for stripping elemental tritium from gas streams has been demonstrated. The process uses a catalyzed isotopic exchange reaction between tritium in the gas phase and protium or deuterium in the solid phase on alumina. The reaction is catalyzed by platinum deposited on the alumina. The process has been tested with both tritium and deuterium. Decontamination factors (ration of inlet and outlet tritium concentrations) as high as 1000 have been achieved, depending on inlet concentration. The test results and some demonstrated applications are presented

  6. Heterogeneous Photooxidation of Phenol by Catalytic Membranes

    Institute of Scientific and Technical Information of China (English)

    Enrica Fontananova; Enrico Drioli; Laura Donato; Marcella Bonchio; Mauro Carraro; Gianfranco Scorrano

    2006-01-01

    In this work the heterogenization in polymeric membranes of decatungstate, a photocatalyst for oxidation reactions,was reported. Solid state characterization techniques confirmed that the catalyst structure was preserved within the polymeric membranes. The catalytic membranes were successfully applied in the aerobic photo-oxidation of phenol, one of the main organic pollutants in wastewater, providing stable and recyclable photocatalytic systems. The dependence of the phenol degradation rate by the catalyst loading and transmembrane pressure was shown. By comparison with homogeneous reaction,the catalyst heterogenized in membrane appears to be more efficient concerning the rate of phenol photodegradation and mineralization.

  7. Catalytic Synthesis Methods for Triazolopyrimidine Derivatives

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new method for catalyzed synthesis of triazolopyrimidine derivatives is reported. Aikylamine reaction with dialkyl cyanodithioiminocarbonate was catalyzed by quaternary ammonium salts at room temperature to yield 3-alkylamine-5-amino-1,2,4-triazole in good quality and high yields. After imidization and reaction with an α,β-unsaturated acid derivative, the reaction intermediate was hydrolyzed in the presence of a Lewis acid to obtain the target product. This novel catalytic method for triazolopyrimidine derivatives can be carried out under inexpen-sive and mild conditions, and is safe and environmentally friendly. IH NMR results for all intermediates are re-ported.

  8. The catalytic residues of Tn3 resolvase

    OpenAIRE

    Olorunniji, F.J.; Stark, W M

    2009-01-01

    To characterize the residues that participate in the catalysis of DNA cleavage and rejoining by the site-specific recombinase Tn3 resolvase, we mutated conserved polar or charged residues in the catalytic domain of an activated resolvase variant. We analysed the effects of mutations at 14 residues on proficiency in binding to the recombination site ('site I'), formation of a synaptic complex between two site Is, DNA cleavage and recombination. Mutations of Y6, R8, S10, D36, R68 and R71 result...

  9. Study and Analysis on Naphtha Catalytic Reforming Reactor Simulation

    Institute of Scientific and Technical Information of China (English)

    Liang Ke min; Song Yongji; Pan Shiwei

    2004-01-01

    A naphtha catalytic reforming unit with four reactors connected in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reaction characteristics based on idealizing the complex naphtha mixture to represent the paraffin, naphthene, and aromatic groups with individual compounds. The simulation results based on above models agree very well with actual operating data of process unit.

  10. A study on naphtha catalytic reforming reactor simulation and analysis

    Institute of Scientific and Technical Information of China (English)

    LIANG Ke-min; GUO Hai-yan; PAN Shi-wei

    2005-01-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

  11. Non-thermal plasmas for non-catalytic and catalytic VOC abatement

    International Nuclear Information System (INIS)

    Highlights: → We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. → The underlying mechanisms of plasma-catalysis for VOC abatement are discussed. → Critical process parameters that determine the influent are discussed and compared. - Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma-catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma-catalytic processes. In both parts (plasma-alone systems and plasma-catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.

  12. Catalytically favorable surface patterns in Pt-Au nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-01-01

    Motivated by recent experimental demonstrations of novel PtAu nanoparticles with highly enhanced catalytic properties, we present a systematic theoretical study that explores principal catalytic indicators as a function of the particle size and composition. We find that Pt electronic states in the vicinity of the Fermi level combined with a modified electron distribution in the nanoparticle due to Pt-to-Au charge transfer are the origin of the outstanding catalytic properties. From our model we deduce the catalytically favorable surface patterns that induce ensemble and ligand effects. © The Royal Society of Chemistry 2013.

  13. Low concentration volatile organic pollutants removal in combined adsorber-desorber-catalytic reactor system

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana

    2008-01-01

    Full Text Available The removal of volatile organic compounds (VOCs from numerous emission sources is of crucial importance due to more rigorous demands on air quality. Different technologies can be used to treat the VOCs from effluent gases: absorption, physical adsorption, open flame combustion, thermal and catalytic incineration. Their appropriateness for the specific process depends on several factors such as efficiency, energy consumption, secondary pollution, capital investments etc. The distinctive features of the catalytic combustion are high efficiency and selectivity toward be­nign products, low energy consumption and absence of secondary polluti­on. The supported noble catalysts are widely used for catalytic incineration due to their low ignition temperatures and high thermal and chemical stability. In our combined system adsorption and desorption are applied in the spouted bed with draft tube (SBDT unit. The annular zone, loaded with sorbent, was divided in adsorption and desorption section. Draft tube enabled sorbent recirculation between sections. Combustion of desorbed gases to CO2 and water vapor are realized in additive catalytic reactor. This integrated device provided low concentrations VOCs removal with reduced energy consumption. Experiments were conducted on a pilot unit of 220 m3/h nominal capacity. The sorbent was activated carbon, type K81/B - Trayal Corporation, Krusevac. A sphere shaped commercial Pt/Al2O3 catalyst with "egg-shell" macro-distribution was used for the investigation of xylene deep oxidation. Within this paper the investigations of removal of xylene vapors, a typical pollutant in production of liquid pesticides, in combined adsorber/desorber/catalytic reactor system is presented.

  14. Side reactions in the selective catalytic reduction of NO with NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Madia, G.; Koebel, M.; Elsener, M.; Wokaun, A.

    2002-03-01

    The main and the side reactions of the SCR reaction with ammonia over TiO{sub 2}-WO{sub 3}-V{sub 2}O{sub 5} catalysts have been investigated using synthetic gas mixtures matching the composition of diesel exhaust. At high temperatures the selective catalytic oxidation of ammonia (SCO) and the formation of nitrous oxide compete with the SCR reaction. Water strongly inhibits the SCO of ammonia and the formation of nitrous oxide thus increasing the selectivity of the SCR reaction. However, water also inhibits SCR activity, most pronounced at low temperatures. (author)

  15. Aluminosilicate nanoparticles for catalytic hydrocarbon cracking.

    Science.gov (United States)

    Liu, Yu; Pinnavaia, Thomas J

    2003-03-01

    Aluminosilicate nanoparticles containing 9.0-20 nm mesopores were prepared through the use of protozeolitic nanoclusters as the inorganic precursor and starch as a porogen. The calcined, porogen-free composition containing 2 mol % aluminum exhibited the porosity, hydrothermal stability, and acidity needed for the cracking of very large hydrocarbons. In fact, the hydrothermal stability of the nanoparticles to pure steam at 800 degrees C, along with the cumene cracking activity, surpassed the analogous performance properties of ultrastable Y zeolite, the main catalyst component of commercial cracking catalysts. The remarkable hydrothermal stability and catalytic reactivity of the new nanoparticles are attributable to a unique combination of two factors, the presence of protozeolitic nanoclusters in the pore walls and the unprecedented pore wall thickness (7-15 nm). In addition, the excellent catalytic longevity of the nanoparticles is most likely facilitated by the small domain size of the nanoparticles that greatly improves access to the acid sites on the pore walls and minimizes the diffusion length of coke precursors out of the pores. PMID:12603109

  16. Catalytic converter for next generation turbine engines

    Energy Technology Data Exchange (ETDEWEB)

    Saruhan, B.; Schulz, U.; Leyens, C. [German Aerospace Center (DLR), Inst. of Materials Research, Cologne (Germany)

    2004-07-01

    EB-PVD thermal barrier coatings (TBCs) are used on advanced turbine blades to increase the engine efficiency and improve the blade performance. partially yttria stabilized zirconia (PYSZ) is the standard material for current TBC applications. Lower thermal stability of the PYSZ-based TBCs, however, seriously affects the performance at demanding service temperatures. For the new generation turbines where higher operating gas temperatures (> 1200 C) are to expect, the performance of turbine blades can be improved by replacing the state-art-of-material PYSZ with superior thermal barrier coatings which belong to different crystal structures such as magnetoplumbite. Magnetoplumbite structure through its interlocking grain morphology and unique crystal structure provides essentially a sintering resistant, low thermal conductive layer, but also imparts a catalytic layer to reduce the environmentally harmful substances produced during propulsion and increase the catalytic performance. The complex structures of these compounds make it difficult to realize by conventional methods and requires careful adjustment of process parameters. The morphology and crystallographic aspects of these coatings as well as the mechanisms controlling the improvement are highlighted. (orig.)

  17. Catalytic reactor for low-Btu fuels

    Science.gov (United States)

    Smith, Lance; Etemad, Shahrokh; Karim, Hasan; Pfefferle, William C.

    2009-04-21

    An improved catalytic reactor includes a housing having a plate positioned therein defining a first zone and a second zone, and a plurality of conduits fabricated from a heat conducting material and adapted for conducting a fluid therethrough. The conduits are positioned within the housing such that the conduit exterior surfaces and the housing interior surface within the second zone define a first flow path while the conduit interior surfaces define a second flow path through the second zone and not in fluid communication with the first flow path. The conduit exits define a second flow path exit, the conduit exits and the first flow path exit being proximately located and interspersed. The conduits define at least one expanded section that contacts adjacent conduits thereby spacing the conduits within the second zone and forming first flow path exit flow orifices having an aggregate exit area greater than a defined percent of the housing exit plane area. Lastly, at least a portion of the first flow path defines a catalytically active surface.

  18. Electrochemical promotion of sulfur dioxide catalytic oxidation

    DEFF Research Database (Denmark)

    Petrushina, Irina; Bandur, Viktor; Cappeln, Frederik Vilhelm;

    2000-01-01

    The effect of electrochemical polarization on the catalytic SO2 oxidation in the molten V2O5-K2S2O7 system has been studied using a gold working electrode in the temperature range 400-460 degrees C. A similar experiment has been performed with the industrial catalyst VK-58. The aim of the present...... investigation was to study a possible non-Faradaic electrochemical promotion of the liquid-phase catalytic reaction. It has been shown that there are two negative potential promotion areas with maximum effects at approximately -0.1 and -0.2 V, and one positive potential promotion area with the maximum effect...... caused by the negative charge on the electrode. The Faradaic part of the promoting effect under positive polarization has been explained as the electrochemical pushing of the V(V) V(IV) equilibrium in the direction of V(V) formation. It has also been shown that when using the industrial VK-58 catalyst...

  19. Computational and Physical Analysis of Catalytic Compounds

    Science.gov (United States)

    Wu, Richard; Sohn, Jung Jae; Kyung, Richard

    2015-03-01

    Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

  20. Catalytic Deoxydehydration of Carbohydrates and Polyols to Chemicals and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Kenneth M. [Univ. of Oklahoma, Norman, OK (United States)

    2016-01-15

    As the world's fossil fuel resources are being depleted and their costs increase, there is an urgent need to discover and develop new processes for the conversion of renewable, biomass resources into fuels and chemical feedstocks. Research and development in this area have been given high priority by both governmental agencies and industry. To increase the energy content and decrease the boiling points of biomass-derived carbohydrates and polyols to the useful liquid range it is necessary to chemically remove water (dehydrate) and, preferably, oxygen (deoxygenate/reduce). The poly-hydroxylic nature of carbohydrates is attractive for their use as functionalized chemical building blocks, but it presents a daunting challenge for their selective conversion to single product chemicals or fuels. The long term, practical objective of this project is to develop catalytic processes for the deoxydehydration (DODH) of biomass-derived carbohydrates and polyols to produce unsaturated alcohols and hydrocarbons of value as chemical feedstocks and fuels; DODH: polyol + reductant --(LMOx catalyst)--> unsaturate + oxidized reductant + H2O. Limited prior studies have established the viability of the DODH process with expensive phosphine reductants and rhenium-catalysts. Initial studies in the PI's laboratory have now demonstrated: 1) the moderately efficient conversion of glycols to olefins by the economical sulfite salts is catalyzed by MeReO3 and Z+ReO4-; 2) effective phosphine-based catalytic DODH of representative glycols to olefins by cheap LMoO2 complexes; and 3) computational studies (with K. Houk, UCLA) have identified several Mo-, W-, and V-oxo complexes that are likely to catalyze glycol DODH. Seeking practically useful DODH reactions of complex polyols and new understanding of the reactivity of polyoxo-metal species with biomass-oxygenates we will employ a two-pronged approach: 1) investigate experimentally the reactivity, both stoichiometric and catalytic, of

  1. Cations and hydration in catalytic RNA: molecular dynamics of the hepatitis delta virus ribozyme.

    Science.gov (United States)

    Krasovska, Maryna V; Sefcikova, Jana; Réblová, Kamila; Schneider, Bohdan; Walter, Nils G; Sponer, Jirí

    2006-07-15

    The hepatitis delta virus (HDV) ribozyme is an RNA enzyme from the human pathogenic HDV. Cations play a crucial role in self-cleavage of the HDV ribozyme, by promoting both folding and chemistry. Experimental studies have revealed limited but intriguing details on the location and structural and catalytic functions of metal ions. Here, we analyze a total of approximately 200 ns of explicit-solvent molecular dynamics simulations to provide a complementary atomistic view of the binding of monovalent and divalent cations as well as water molecules to reaction precursor and product forms of the HDV ribozyme. Our simulations find that an Mg2+ cation binds stably, by both inner- and outer-sphere contacts, to the electronegative catalytic pocket of the reaction precursor, in a position to potentially support chemistry. In contrast, protonation of the catalytically involved C75 in the precursor or artificial placement of this Mg2+ into the product structure result in its swift expulsion from the active site. These findings are consistent with a concerted reaction mechanism in which C75 and hydrated Mg2+ act as general base and acid, respectively. Monovalent cations bind to the active site and elsewhere assisted by structurally bridging long-residency water molecules, but are generally delocalized.

  2. Catalytic hydrothermal pretreatment of corncob into xylose and furfural via solid acid catalyst.

    Science.gov (United States)

    Li, Huiling; Deng, Aojie; Ren, Junli; Liu, Changyu; Lu, Qi; Zhong, Linjie; Peng, Feng; Sun, Runcang

    2014-04-01

    Selectively catalytic hydrothermal pretreatment of corncob into xylose and furfural has been developed in this work using solid acid catalyst (SO4(2-)/TiO2-ZrO2/La(3+)). The effects of corncob-to-water ratio, reaction temperature and residence time on the performance of catalytic hydrothermal pretreatment were investigated. Results showed that the solid residues contained mainly lignin and cellulose, which was indicative of the efficient removal of hemicelluloses from corncob by hydrothermal method. The prepared catalyst with high thermal stability and strong acid sites originated from the acid functional groups was confirmed to contribute to the hydrolysis of polysaccharides into monosaccharides followed by dehydration into furfural. Highest furfural yield (6.18 g/100g) could be obtained at 180°C for 120 min with 6.80 g/100g xylose yield when the corncob/water ratio of was 10:100. Therefore, selectively catalytic hydrothermal pretreatment of lignocellulosic biomass into important platform chemicals by solid acids is considered to be a potential treatment for biodiesel and chemical production.

  3. Polarographic catalytic wave of hydrogen--Parallel catalytic hydrogen wave of bovine serum albumin in thepresence of oxidants

    Institute of Scientific and Technical Information of China (English)

    GUO; Wei(过玮); LIU; Limin(刘利民); LIN; Hong(林洪); SONG; Junfeng(宋俊峰)

    2002-01-01

    A polarographic catalytic hydrogen wave of bovine serum albumin (BSA) at about -1.80 V (vs. SCE) in NH4Cl-NH3@H2O buffer is further catalyzed by such oxidants as iodate, persulfate and hydrogen peroxide, producing a kinetic wave. Studies show that the kinetic wave is a parallel catalytic wave of hydrogen, which resulted from that hydrogen ion is electrochemically reduced and chemically regenerated through oxidation of its reduction product, atomic hydrogen, by oxidants mentioned above. It is a new type of poralographic catalytic wave of protein, which is suggested to be named as a parallel catalytic hydrogen wave.

  4. Influence of Ammonia Leaching on the Structure and Catalytic Performance of CuO/CeO2 Catalysts for Water -gas Shift Reaction%氨沥滤对 CuO/CeO2变换催化剂结构和性能的影响

    Institute of Scientific and Technical Information of China (English)

    何润霞; 赵文怡; 智科端; 武芳; 周晨亮; 刘全生

    2013-01-01

    本文以CeO2为载体,采用浸渍法制备了不同铜负载量的CuO/CeO2水煤气变换催化剂,并以其为前驱体,通过氨沥滤改变CuO/CeO2催化剂中铜负载量,利用XRD、BET、TPR和活性测试等对催化剂样品的结构及催化性能进行比较研究。结果表明,铜负载量大小是影响CuO/CeO2催化剂结构与性能的重要因素,不同铜负载量的CuO/CeO2样品经氨水沥滤后没有改变原有结晶度的变化规律及物相组成,但晶粒度均提高。 CuO负载量小于12%,氨沥滤后样品的比表面积和孔容均减小,催化活性降低。 CuO负载量大于12%,氨沥滤后样品的比表面积和孔容降低幅度较CuO负载量小于12%样品小,活性降幅很小或反而提高。%In this paper , the CuO/CeO2 water gas shift catalysts with different copper loading capacities were prepared by incipient wet impregnation while CeO 2 was used as catalyst support .With the catalysts as precursors , the ion embed-leached type CuO/CeO2 catalysts were prepared through NH 3 · H2 O leaching, by using the feature that Copper ions are liable to be leached by NH3 · H2 O.The structure and performance of the catalyst were characterized by XRD , BET and TPR, and the activities on the shift reaction were also tested .The results show that: the copper loading capacity was an important factor to the structures and properties of CuO/CeO2 catalysts.NH3 · H2 O leaching process did not change to the overall change trends of the crystallinity of samples and phase composition , but grain size of samples increased after NH 3 · H2 O leaching .When CuO loadings were less than 12%, specific surface area and pore volume of leached samples decreased , and the catalytic activity decreased , too.While CuO loadings were more than 12%, specific surface area and pore volume of leached samples also decreased , but the extent of decreasing was less than the amount that CuO loadings were less than 12%.Therefore, the

  5. Anisotropic magnetic porous assemblies of oxide nanoparticles interconnected via silica bridges for catalytic application.

    Science.gov (United States)

    Wacker, Josias B; Parashar, Virendra K; Gijs, Martin A M

    2011-04-19

    We report the microfluidic chip-based assembly of colloidal silanol-functionalized silica nanoparticles using monodisperse water-in-oil droplets as templates. The nanoparticles are linked via silica bridges, thereby forming superstructures that range from doublets to porous spherical or rod-like micro-objects. Adding magnetite nanoparticles to the colloid generates micro-objects that can be magnetically manipulated. We functionalized such magnetic porous assemblies with horseradish peroxidase and demonstrate the catalytic binding of fluorescent dye-labeled tyramide over the complete effective surface of the superstructure. Such nanoparticle assemblies permit easy manipulation and recovery after a heterogeneous catalytic process while providing a large surface similar to that of the individual nanoparticles. PMID:21417232

  6. PREPARATION AND CATALYTIC BEHAVIOUR OF POLYMER-BOUND METALLOPORPHYRIN IN HYDROGENATION OF OLEFIN

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The meso-tetraarylporphyrin has been anchored to styrene-divinylbenzene copolymers by reaction of meso-tetra(4-hydroxylphenyl) porphyrin with chloromethylated resin under mild condition. A number of polymer transition metal complexes have been prepared with the polymer ligand and metal salts. The polymeric ligand and its complexes have been characterized by electronic spectra, and vibrational spectra. Cyclohexene can be hydrogenated with the polymeric porphyrin palladium complex(P-THPPPd) as catalyst, and its catalytic activity was influenced by the polarity of solvents, the contents of water in ethanol or reaction temperature. However, its catalytic activity was lower for nitro groups, carbonyl groups and olefins with steric hindrance substituents, and showed no activity for aromatic rings under these conditions.

  7. Selective catalytic reduction of nitric oxide by ammonia over Cu-exchanged Cuban natural zeolites

    International Nuclear Information System (INIS)

    The catalytic selective reduction of NO over Cu-exchanged natural zeolites (mordenite (MP) and clinoptilolite (HC)) from Cuba using NH3 as reducing agent and in the presence of excess oxygen was studied. Cu(II)-exchanged zeolites are very active catalysts, with conversions of NO of 95%, a high selectivity to N2 at low temperatures, and exhibiting good water tolerance. The chemical state of the Cu(II) in exchanged zeolites was characterized by H2-TPR and XPS. Cu(II)-exchanged clinoptilolite underwent a severe deactivation in the presence of SO2. However, Cu(II)-exchanged mordenite not only maintained its catalytic activity, but even showed a slight improvement after 20h of reaction in the presence of 100ppm of SO2

  8. Catalytic oxidation for treatment of ECLSS and PMMS waste streams. [Process Material Management Systems

    Science.gov (United States)

    Akse, James R.; Thompson, John; Scott, Bryan; Jolly, Clifford; Carter, Donald L.

    1992-01-01

    Catalytic oxidation was added to the baseline multifiltration technology for use on the Space Station Freedom in order to convert low-molecular weight organic waste components such as alcohols, aldehydes, ketones, amides, and thiocarbamides to CO2 at low temperature (121 C), thereby reducing the total organic carbon (TOC) to below 500 ppb. The rate of reaction for the catalytic oxidation of aqueous organics to CO2 and water depends primarily upon the catalyst, temperature, and concentration of reactants. This paper describes a kinetic study conducted to determine the impact of each of these parameters upon the reaction rate. The results indicate that a classic kinetic model, the Langmuir-Hinshelwood rate equation for heterogeneous catalysis, can accurately represent the functional dependencies of this rate.

  9. Catalytic Activity and Photophysical Properties of Biomolecules Immobilized on Mesoporous Silica

    DEFF Research Database (Denmark)

    Ikemoto, Hideki

    Michaelis constant (KM) and maximum rate (Vmax) were determined. Both thermal stability and the stability toward the denaturing agents guanidinium chloride and urea, of free and immobilized enzymes were compared next. The thermal stability of the immobilized enzyme is significantly improved in comparison...... with free HRP. The catalytic kinetics is slowed down notably, but Vmax is much more robust to heat than for the free enzyme. The stability resistance of the enzyme toward the denaturing agents depends on the chemical nature of the denaturing agentsand interactions between enzyme and silica nanopore walls....... Guanidinium chloride showed similar attenuation of the catalytic activity of immobilized and free enzyme. In contrast, immobilized HRP was much more resistant to urea than the free enzyme. The different behavior of free and immobilized enzyme is most likely due to different hydrogen bonding of water...

  10. Efficiency enhancement of wood stove integrated with catalytic combustor and modified chimney

    Directory of Open Access Journals (Sweden)

    G. Murali

    2014-12-01

    Full Text Available Domestic wood combustion produces smoke that is harmful to human health and increases fine particle level in the atmosphere. Some necessary changes in the design are essential in the domestic wood stove in order to improve the performance and scale down the emission. In this work, an improved wood stove integrated with the catalytic combustor and modified chimney that uses wood as fuel has been experimentally evaluated. Water boiling test, cooking test and emission test have been conducted to evaluate the performance of the stove. It was observed that emission has been considerably controlled because of the incorporation of catalytic combustor. The heat losses through the walls of stove decresed by providing ceramic insulation. The thermal efficiency value of an improved wood stove obtained was 41.18% and this is 31.52% higher than traditional stove. The improved wood stove results better performance than a traditional wood stove.

  11. Catalytic non-thermal plasma reactor for the decomposition of a mixture of volatile organic compounds

    Indian Academy of Sciences (India)

    B Rama Raju; E Linga Reddy; J Karuppiah; P Manoj Kumar Reddy; Ch Subrahmanyam

    2013-05-01

    The decomposition of mixture of selected volatile organic compounds (VOCs) has been studied in a catalytic non-thermal plasma dielectric barrier discharge reactor. The VOCs mixture consisting n-hexane, cyclo-hexane and -xylene was chosen for the present study. The decomposition characteristics of mixture of VOCs by the DBD reactor with inner electrode modified with metal oxides of Mn and Co was studied. The results indicated that the order of the removal efficiency of VOCs followed as -xylene > cyclo-hexane > -hexane. Among the catalytic study, MnOx/SMF (manganese oxide on sintered metal fibres electrode) shows better performance, probably due to the formation of active oxygen species by in situ decomposition of ozone on the catalyst surface. Water vapour further enhanced the performance due to the in situ formation of OH radicals.

  12. H2CAP - Hydrogen assisted catalytic biomass pyrolysis for green fuels

    DEFF Research Database (Denmark)

    Arndal, Trine Marie Hartmann; Høj, Martin; Jensen, Peter Arendt;

    2014-01-01

    Pyrolysis of biomass produces a high yield of condensable oil at moderate temperature and low pressure.This bio-oil has adverse properties such as high oxygen and water contents, high acidity and immiscibility with fossil hydrocarbons. Catalytic hydrodeoxygenation (HDO) is a promising technology...... that can be used to upgrade the crude bio-oil to fuel-grade oil. The development of the HDO process is challenged by rapid catalyst deactivation, instability of the pyrolysis oil, poorly investigated reaction conditions and a high complexity and variability of the input oil composition. However, continuous...... catalytic hydropyrolysis coupled with downstream HDO of the pyrolysis vapors before condensation shows promise (Figure 1). A bench scale experimental setup will be constructed for the continuous conversion of solid biomass (100g /h) to low oxygen, fuel-grade bio-oil. The aim is to provide a proof...

  13. Selective catalytic reduction of nitrogen oxides from industrial gases by hydrogen or methane

    International Nuclear Information System (INIS)

    This work deals with the selective catalytic reduction of nitrogen oxides (NOx), contained in the effluents of industrial plants, by hydrogen or methane. The aim is to replace ammonia, used as reducing agent, in the conventional process. The use of others reducing agents such as hydrogen or methane is interesting for different reasons: practical, economical and ecological. The catalyst has to convert selectively NO into N2, in presence of an excess of oxygen, steam and sulfur dioxide. The developed catalyst is constituted by a support such as perovskites, particularly LaCoO3, on which are dispersed noble metals (palladium, platinum). The interaction between the noble metal and the support, generated during the activation of the catalyst, allows to minimize the water and sulfur dioxide inhibitor phenomena on the catalytic performances, particularly in the reduction of NO by hydrogen. (O.M.)

  14. The effects of sodium hypochlorite on the control of inter-kingdom biofilm formation by drinking water-isolated microorganisms

    OpenAIRE

    Simões, Lúcia C; Chaves, Ana F.A.; Simões, Manuel; Lima, Nelson

    2015-01-01

    Biofilms in drinking water distribution systems (DWDS) are responsible for several undesirable effects in water. One of the main drawbacks is their potential to protect pathogens from stress conditions. Microbial interactions in biofilms can benefit the survival of co existing microorganisms, including the increased resistance to antimicrobials. Chlorine disinfection is the main widespread strategy used in DWDS for microbial control. Even if new and alternative strategies are b...

  15. Evaluation of Performance Catalytic Ozonation Process with Activated Carbon in the Removal of Humic Acids from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Gh. Asgari

    2011-01-01

    Full Text Available Introduction & Objective: In recent years, the use of alternative disinfectants and the control of natural organic matters are two approaches that are typically applied in water treatment utilities to reduce the formation of chlorinated disinfection by-products. Catalytic ozonation is a new technology used to promote the efficiency of ozonation. The goal of this study was to survey the feasibility application of activated carbon as a catalyst in ozonation process for removal of humic acids from aqueous solution. Materials & Methods: This experimental study has been done in laboratory of water and wastewater chemistry, Tarbiat Modarres University. The solid structure and chemical composition of activated carbon were analyzed by X-ray fluorescence (XRF. Ozonation and catalytic ozonation experiments were performed in a semi-batch reactor and the mass of ozone produced was measured by iodometric titration methods. Concentration changes of humic acid in samples with a concentration of 15 mg/l were determined by using spectrophotometer at an absorbance wavelength of 254 nm. To evaluate the performance of catalytic ozonation in humic acid removal, total organic carbon and trihalomethane formation potential were evaluated and the results were analyzed by Excel software. Results: Catalytic ozone results showed that using activated carbon as a catalyst increased humic acid decomposition up to 11 times and removal efficiency increased with increasing pH (4-12 and catalyst dosage (0.25-1.5 g/250cc. The experimental results showed that catalytic ozonation was most effective in less time (10 min with considerable efficiency (95% compared to the sole ozonation process (SOP. Conclusion: The results indicated that the catalytic ozonation process, compared to SOP, was less affected by radical scavenger, and total organic carbon, and trihalomethane formation potential removal achieved were 30% and 83%, respectively. (Sci J Hamadan Univ Med Sci 2011;17(4:25-33

  16. A QM/MM study of the catalytic mechanism of nicotinamidase.

    Science.gov (United States)

    Sheng, Xiang; Liu, Yongjun

    2014-02-28

    Nicotinamidase (Pnc1) is a member of Zn-dependent amidohydrolases that hydrolyzes nicotinamide (NAM) to nicotinic acid (NA), which is a key step in the salvage pathway of NAD(+) biosynthesis. In this paper, the catalytic mechanism of Pnc1 has been investigated by using a combined quantum-mechanical/molecular-mechanical (QM/MM) approach based on the recently obtained crystal structure of Pnc1. The reaction pathway, the detail of each elementary step, the energetics of the whole catalytic cycle, and the roles of key residues and Zn-binding site are illuminated. Our calculation results indicate that the catalytic water molecule comes from the bulk solvent, which is then deprotonated by residue D8. D8 functions as a proton transfer station between C167 and NAM, while the activated C167 serves as the nucleophile. The residue K122 only plays a role in stabilizing intermediates and transition states. The oxyanion hole formed by the amide backbone nitrogen atoms of A163 and C167 has the function to stabilize the hydroxyl anion of nicotinamide. The Zn-binding site rather than a single Zn(2+) ion acts as a Lewis acid to influence the reaction. Two elementary steps, the activation of C167 in the deamination process and the decomposition of catalytic water in the hydrolysis process, correspond to the large energy barriers of 25.7 and 28.1 kcal mol(-1), respectively, meaning that both of them contribute a lot to the overall reaction barrier. Our results may provide useful information for the design of novel and efficient Pnc1 inhibitors and related biocatalytic applications. PMID:24413890

  17. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    measurements of gas-phase catalytic products. To overcome this deficiency, operando TEM techniques are being developed that combine atomic characterization with the simultaneous measurement of catalytic products. This article provides a short review of the current status and major developments in the...

  18. Catalytic activities of platinum nanotubes: a density functional study

    Science.gov (United States)

    Mukherjee, Prajna; Gupta, Bikash C.; Jena, Puru

    2015-10-01

    In this work we investigate the catalytic properties of platinum nanotubes using density functional theory based calculations. In particular, we study the dissociation of hydrogen and oxygen molecules as well as oxidation of CO molecules. The results indicate that platinum nanotubes have good catalytic properties and can be effectively used in converting CO molecule to CO2.

  19. Including lateral interactions into microkinetic models of catalytic reactions

    DEFF Research Database (Denmark)

    Hellman, Anders; Honkala, Johanna Karoliina

    2007-01-01

    In many catalytic reactions lateral interactions between adsorbates are believed to have a strong influence on the reaction rates. We apply a microkinetic model to explore the effect of lateral interactions and how to efficiently take them into account in a simple catalytic reaction. Three...

  20. Catalytic pyrolysis of oilsand bitumen over nanoporous catalysts.

    Science.gov (United States)

    Lee, See-Hoon; Heo, Hyeon Su; Jeong, Kwang-Eun; Yim, Jin-Heong; Jeon, Jong-Ki; Jung, Kyeong Youl; Ko, Young Soo; Kim, Seung-Soo; Park, Young-Kwon

    2011-01-01

    The catalytic cracking of oilsand bitumen was performed over nanoporous materials at atmospheric conditions. The yield of gas increased with application of nanoporous catalysts, with the catalytic conversion to gas highest for Meso-MFI. The cracking activity seemed to correlate with pore size rather than weak acidity or surface area. PMID:21446540