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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.

    Science.gov (United States)

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

    2009-11-17

    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. 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. 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.

  3. Water-use strategies of six co-existing Mediterranean woody species during a summer drought

    NARCIS (Netherlands)

    Quero, J.L.; Sterck, F.J.; Martínez-Vilalta, J.; Villar, R.

    2011-01-01

    Drought stress is known to limit plant performance in Mediterranean-type ecosystems. We have investigated the dynamics of the hydraulics, gas exchange and morphology of six co-existing Mediterranean woody species growing under natural field conditions during a drought that continued during the

  4. Catalytic detritiation of water

    International Nuclear Information System (INIS)

    Rogers, M.L.; Lamberger, P.H.; Ellis, R.E.; Mills, T.K.

    1977-01-01

    A pilot-scale system has been used at Mound Laboratory to investigate the catalytic detritiation of water. A hydrophobic, precious metal catalyst is used to promote the exchange of tritium between liquid water and gaseous hydrogen at 60 0 C. Two columns are used, each 7.5 m long by 2.5 cm ID and packed with catalyst. Water flow is 5-10 cm 3 /min and countercurrent hydrogen flow is 9,000-12,000 cm 3 /min. The equipment, except for the columns, is housed in an inert atmosphere glovebox and is computer controlled. The hydrogen is obtained by electrolysis of a portion of the water stream. Enriched gaseous tritium is withdrawn for further enrichment. A description of the system is included along with an outline of its operation. Recent experimental data are discussed

  5. High efficient removal of molybdenum from water by Fe{sub 2}(SO{sub 4}){sub 3}: Effects of pH and affecting factors in the presence of co-existing background constituents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiang; Ma, Jun, E-mail: majunhit@126.com; Lu, Xixin; Huangfu, Xiaoliu; Zou, Jing

    2015-12-30

    Highlights: • Proposed high efficient Mo (VI) removal with Fe{sub 2}(SO{sub 4}){sub 3} coagulation-filtration. • Studied different effects of Fe{sub 2}(SO{sub 4}){sub 3} and FeCl{sub 3} due to different anionic portions. • Reported the adverse effect of calcium on the removal of Mo (VI). • Proposed factors affecting Mo (VI) removal: intercepted Fe and adsorption affinity. - Abstract: Comparatively investigated the different effects of Fe{sub 2}(SO{sub 4}){sub 3} coagulation-filtration and FeCl{sub 3} coagulation-filtration on the removal of Mo (VI). And the influence of calcium, sulfate, silicate, phosphate and humic acid (HA) were also studied. The following conclusions can be obtained: (1) compared with the case of FeCl{sub 3}, Fe{sub 2}(SO{sub 4}){sub 3} showed a higher Mo (VI) removal efficiency at pH 4.00–5.00, but an equal removal efficiency at pH 6.00–9.00. (2) The optimum Mo (VI) removal by Fe{sub 2}(SO{sub 4}){sub 3} was achieved at pH 5.00–6.00; (3) The presence of calcium can reduce the removal of Mo (VI) over the entire pH range in the present study; (4) The effect of co-existing background anions (including HA) was dominated by three factors: Firstly the influence of co-existing background anions on the content of Fe intercepted from water (intercepted Fe). Secondly the competition of co-existing anions with Mo (VI) for adsorption sites. Thirdly the influence of co-existing background anions on the Zeta potential of the iron flocs.

  6. Germination sensitivities to water potential among co-existing C3 and C4 grasses of cool semi-arid prairie grasslands.

    Science.gov (United States)

    Mollard, F P O; Naeth, M A

    2015-03-01

    An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk-spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non-dormant seeds under different Ψ PEG 6000 solutions. A t-test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb (50)). We found idiosyncratic responses of C4 grasses along the risk-spreading continuum. B. gracilis showed a risk-taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb (50) and hydrotime (θH ). The high Ψb (50) of S. scoparium indicates it follows the risk-averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb (50) yet the highest θH . K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb (50), suggesting a risk-averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk-spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  7. Co-existence in multispecies biofilm communities

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng

    of these emergent properties which are relevant to as diverse areas as clinical settings and natural systems. In this thesis, I have attempted to contribute to our knowledge on the multispecies interactions with a special focus on biofilm communities. I was especially interested in how co-existing species affect...... each other and in understanding the key mechanisms and interactions involved. In the introduction of this thesis the most important concepts of multi-species interactions and biofilm development are explained. After this the topic changes to the various ways of examining community interactions...... and production. The analysis was further extended in manuscript 3, in which the effect of social interac-tions on biofilm formation in multispecies co-cultures isolated from a diverse range of environments was examined. The question raised was whether the interspecific interactions of co-existing bacteria...

  8. Photolytic AND Catalytic Destruction of Organic Waste Water Pollutants

    Science.gov (United States)

    Torosyan, V. F.; Torosyan, E. S.; Kryuchkova, S. O.; Gromov, V. E.

    2017-01-01

    The system: water supply source - potable and industrial water - wastewater - sewage treatment - water supply source is necessary for water supply and efficient utilization of water resources. Up-to-date technologies of waste water biological treatment require for special microorganisms, which are technologically complex and expensive but unable to solve all the problems. Application of photolytic and catalytically-oxidizing destruction is quite promising. However, the most reagents are strong oxidizers in catalytic oxidation of organic substances and can initiate toxic substance generation. Methodic and scientific approaches to assess bread making industry influence on the environment have been developed in this paper in order to support forecasting and taking technological decisions concerning reduction of this influence. Destructive methods have been tested: ultra violet irradiation and catalytic oxidation for extraction of organic compounds from waste water by natural reagents.

  9. Magnetic nesting and co-existence of ferromagnetism and superconductivity

    International Nuclear Information System (INIS)

    Elesin, V.F.; Kapaev, V.V.; Kopaev, Yu.V.

    2004-01-01

    In the case of providing for the magnetic nesting conditions of the electron spin dispersion law the co-existence of ferromagnetism and superconductivity is possible by any high magnetization. The co-existence of ferromagnetism and superconductivity in the layered cuprate compounds of the RuSr 2 GdCu 2 O 8 -type is explained on this basis, wherein due to the nonstrict provision of the magnetic nesting condition there exists the finite but sufficiently high critical magnetization [ru

  10. On channel selection and shape co-existence

    International Nuclear Information System (INIS)

    Dracoulis, G.D.

    1993-08-01

    Ambivalence with respect to a favoured shape is emerging as a ubiquitous phenomenon in nuclei. Multiple minima in the nuclear potential well occur because of the delicate balance in nuclei between the long and short-range properties of the nuclear force and the contribution specific particle orbitals make in forcing the nucleus to a decision. Exploration of the dependence of the resulting shape co-existence on particle number and orbital is a prominent area of research. Experimental aspects of spectroscopy studies using heavy ion fusion, evaporation reactions and channel selection are discussed, with focus on shape co-existence in the light Os-Pt-Hg-Pb region. 42 refs., 8 figs

  11. Water detritiation: better catalysts for liquid phase catalytic exchange

    International Nuclear Information System (INIS)

    Braet, J.

    2005-01-01

    Fusion reactors are our hope for a clean nuclear energy. But as they shall handle huge amounts of tritium, 1.5 10 19 Bq GWth -1 a -1 or about 50 000 times more tritium than light water fission reactors, they need detritiation. Most tritium losses can be trapped as or can easily be transformed into tritiated water. Water detritiation is preferably based on the multiplication of the large equilibrium isotope effect during the exchange reaction of tritium between hydrogen gas and liquid water in a counter current trickle bed reactor. Such LPCE (Liquid Phase Catalytic Exchange) requires an efficient hydrophobic catalyst. SCK-CEN invented and developed such a catalyst in the past. In combination with an appropriate packing, different batches of this catalyst performed very well during years of extensive testing, allowing to develop the ELEX process for water detritiation at inland reprocessing plants. The main objectives of this study were to reproduce and possibly improve the SCK-CEN catalyst for tritium exchange between hydrogen and liquid water; and to demonstrate the high overall exchange rate and thus high detritiation factors that can be realized with it in a small and simple LPCE column under typical but conservative operating conditions

  12. Education for a Culture of Peace and Co-Existence

    Directory of Open Access Journals (Sweden)

    Silvia Guetta

    2016-07-01

    Full Text Available Education is a key and fundamental tool required to achieve social change, especially regarding social cohesion and co-existence. Education affects the most critical issues facing humanity, including the proliferation of various forms of violence, environmental degradation, and annihilation of cultures. I argue that the impact of education is equal to that of economics, politics, and technological advances. Therefore, if we wish to see change, educational reform has to be designed to operate in a global-human context, empowering and allowing people to achieve their potential. It should instil in individuals and groups respect for others with whom they interact, in a global as well as local sense. The article draws on the theories of Edgar Morin, Reuven Feuerstein, and Jerome Bruner, and their contributions to the development of educational approaches that encourage a culture of responsible, participatory, and creative coexistence. .

  13. Catalytic Enzyme-Based Methods for Water Treatment and Water Distribution System Decontamination. 1. Literature Survey

    Science.gov (United States)

    2006-06-01

    best examples of this is glucose isomerase, which has been used in the commercial production of high fructose corn syrup (HFCS) since 1967.230 Most...EDGEWOOD CHEMICAL BIOLOGICAL CENTER U.S. ARMY RESEARCH, DEVELOPMENT AND ENGINEERING COMMAND ECBC-TR-489 CATALYTIC ENZYME-BASED METHODS FOR WATER ...TREATMENT AND WATER DISTRIBUTION SYSTEM DECONTAMINATION 1. LITERATURE SURVEY Joseph J. DeFrank RESEARCH AND TECHNOLOGY DIRECTORATE June 2006 Approved for

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

    International Nuclear Information System (INIS)

    Drinovac, P.

    2006-01-01

    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.)

  15. 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.

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

    International Nuclear Information System (INIS)

    Iseli, M.; Schaub, M.; Ulrich, D.

    1992-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Nadejde, C., E-mail: claudia.nadejde@uaic.ro [Interdisciplinary Research Department – Field Science, ‘Alexandru Ioan Cuza’ University, Lascar Catargi 54, 700107 Iasi (Romania); Neamtu, M., E-mail: mariana.neamtu@uaic.ro [Interdisciplinary Research Department – Field Science, ‘Alexandru Ioan Cuza’ University, Lascar Catargi 54, 700107 Iasi (Romania); Schneider, R.J.; Hodoroaba, V.-D. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Ababei, G. [National Institute of Research and Development for Technical Physics, Dimitrie Mangeron Bd. 47, 700050 Iasi (Romania); Panne, U. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin (Germany)

    2015-10-15

    Graphical abstract: - Highlights: • Non-hazardous, facile and inexpensive procedure for efficient wastewater treatment. • Chemical synthesis of ferrous oxalate modified Fe{sub 3}O{sub 4} nanoparticles. • Structural characterization confirmed the senzitized catalysts' nanometric size. • The highly magnetic catalysts can be easily recovered from solution. • 99.7% of azo dye was removed in 4 h using Fenton-like process in alkaline media. - Abstract: 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 (Fe{sub 3}O{sub 4}) 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, H{sub 2}O{sub 2} 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 H{sub 2}O{sub 2} after 240 min of oxidation for a catalyst concentration of 10 g L{sup −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.

  18. 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.

  19. Catalytic membrane in denitrification of water: a means to facilitate intraporous diffusion of reactants

    NARCIS (Netherlands)

    Ilinich, O.M.; Cuperus, F.P.; Gemert, van R.W.; Gribov, E.N.; Nosova, L.V.

    2000-01-01

    The series of mono- and bi-metallic catalysts with Pd and/or Cu supported over γ-Al 2O 3 was investigated with respect to reduction of nitrate and nitrite ions in water by hydrogen. Pronounced limitations of catalytic performance due to intraporous diffusion of the reactants were observed in the

  20. Tritium removal from air streams by catalytic oxidation and water adsorption

    International Nuclear Information System (INIS)

    Sherwood, A.E.

    1976-06-01

    An effective method of capturing tritium from air streams is by catalytic oxidation followed by water adsorption on a microporous solid adsorbent. Performance of a burner/dryer combination is illustrated by overall mass balance equations. Engineering design methods for packed bed reactors and adsorbers are reviewed, emphasizing the experimental data needed for design and the effect of operating conditions on system performance

  1. Catalytic reforming of glycerol in supercritical water over bimetallic Pt-Ni catalyst

    NARCIS (Netherlands)

    Chakinala, A.G.; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.; de Vlieger, Dennis; Seshan, Kulathuiyer; Brilman, Derk Willem Frederik

    2013-01-01

    Catalytic reforming of pure glycerol for the production of hydrogen at low temperature and short residence times in supercritical water was investigated using a bimetallic Pt–Ni catalyst supported on alumina. Initial tests were carried out to study the reforming activity of bimetallic Pt–Ni

  2. 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.

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

    KAUST Repository

    Hisatomi, Takashi; Takanabe, Kazuhiro; Domen, Kazunari

    2014-01-01

    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

  4. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation, Phase I

    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...

  5. The development of catalytic nucleophilic additions of terminal alkynes in water.

    Science.gov (United States)

    Li, Chao-Jun

    2010-04-20

    One of the major research endeavors in synthetic chemistry over the past two decades is the exploration of synthetic methods that work under ambient atmosphere with benign solvents, that maximize atom utilization, and that directly transform natural resources, such as renewable biomass, from their native states into useful chemical products, thus avoiding the need for protecting groups. The nucleophilic addition of terminal alkynes to various unsaturated electrophiles is a classical (textbook) reaction in organic chemistry, allowing the formation of a C-C bond while simultaneously introducing the alkyne functionality. A prerequisite of this classical reaction is the stoichiometric generation of highly reactive metal acetylides. Over the past decade, our laboratory and others have been exploring an alternative, the catalytic and direct nucleophilic addition of terminal alkynes to unsaturated electrophiles in water. We found that various terminal alkynes can react efficiently with a wide range of such electrophiles in water (or organic solvent) in the presence of simple and readily available catalysts, such as copper, silver, gold, iron, palladium, and others. In this Account, we describe the development of these synthetic methods, focusing primarily on results from our laboratory. Our studies include the following: (i) catalytic reaction of terminal alkynes with acid chloride, (ii) catalytic addition of terminal alkynes to aldehydes and ketones, (iii) catalytic addition of alkynes to C=N bonds, and (iv) catalytic conjugate additions. Most importantly, these reactions can tolerate various functional groups and, in many cases, perform better in water than in organic solvents, clearly defying classical reactivities predicated on the relative acidities of water, alcohols, and terminal alkynes. We further discuss multicomponent and enantioselective reactions that were developed. These methods provide an alternative to the traditional requirement of separate steps in

  6. Co-existence of malaria and urinary tract infection among children ...

    African Journals Online (AJOL)

    Co-existence of malaria and urinary tract infection among children under five: ... was the predominant cause of the UTI and the isolates were highly resistant ... Keywords: Malaria, UTI, antibiotic sensitivity pattern, parasitaemia, bacteriuria, fever ...

  7. 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.

  8. COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER; FINAL

    International Nuclear Information System (INIS)

    Phillip E. Savage

    1999-01-01

    Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, we examined the oxidation of phenol over a commercial catalyst and over bulk MnO(sub 2), bulk TiO(sub 2), and CuO supported on Al(sub 2) O(sub 3). We used phenol as the model pollutant because it is ubiquitous in coal-conversion wastewaters and there is a large database for non-catalytic supercritical water oxidation (SCWO) with which we can contrast results from catalytic SCWO. The overall objective of this research project is to obtain the reaction engineering information required to evaluate the utility of catalytic supercritical water oxidation for treating wastes arising from coal conversion processes. All four materials were active for catalytic supercritical water oxidation. Indeed, all four materials produced phenol conversions and CO(sub 2) yields in excess of those obtained from purely homogeneous, uncatalyzed oxidation reactions. The commercial catalyst was so active that we could not reliably measure reaction rates that were not limited by pore diffusion. Therefore, we performed experiments with bulk transition metal oxides. The bulk MnO(sub 2) and TiO(sub 2) catalysts enhance both the phenol disappearance and CO(sub 2) formation rates during SCWO. MnO(sub 2) does not affect the selectivity to CO(sub 2), or to the phenol dimers at a given phenol conversion. However, the selectivities to CO(sub 2) are increased and the selectivities to phenol dimers are decreased in the presence of TiO(sub 2) , which are desirable trends for a catalytic SCWO process. The role of the catalyst appears to be accelerating the rate of formation of

  9. Combined electrolysis and catalytic exchange (CECE) technology - an economical alternative for heavy water upgraders using water distillation

    International Nuclear Information System (INIS)

    Ryland, D.K.; Sadhankar, R.R.

    2003-01-01

    Heavy water upgrading is a unique and crucial part of a CANDU power station. Water distillation (DW) systems are used for heavy water upgrading in all CANDU stations. The DW upgrader is designed to take advantage of the difference in relative volatility (a measure of separation of isotopes) between H 2 O and D 2 O. However, the low relative volatility of the H 2 O/D 2 O system requires large number of stages (long columns) and large reflux ratios (large reboiler loads) - thus resulting in significant capital and operating costs. Atomic Energy of Canada Limited (AECL) developed the Combined Electrolysis and Catalytic Exchange (CECE) technology as an economical alternative to the DW system. CECE-based upgraders have been demonstrated in pilot scale facilities at AECL Chalk River Laboratories and in Hamilton, Ontario. This design is based on catalytic hydrogen isotope exchange between water and hydrogen gas. (author)

  10. On the study of catalytic membrane reactor for water detritiation: Modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Liger, Karine, E-mail: karine.liger@cea.fr [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France); Mascarade, Jérémy [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France); Joulia, Xavier; Meyer, Xuan-Mi [Université de Toulouse, INPT, UPS, Laboratoire de Génie Chimique, 4, Allée Emile Monso, Toulouse F-31030 (France); CNRS, Laboratoire de Génie Chimique, Toulouse F-31030 (France); Troulay, Michèle; Perrais, Christophe [CEA, DEN, DTN/SMTA/LIPC Cadarache, Saint Paul-lez-Durance F-13108 (France)

    2016-11-01

    Highlights: • Experimental results for the conversion of tritiated water (using deuterium as a simulant of tritium) by means of a catalytic membrane reactor in view of tritium recovery. • Phenomenological 2D model to represent catalytic membrane reactor behavior including the determination of the compositions of gaseous effluents. • Good agreement between the simulation results and experimental measurements performed on the dedicated facility. • Explanation of the unexpected behavior of the catalytic membrane reactor by the modeling results and in particular the gas composition estimation. - Abstract: In the framework of tritium recovery from tritiated water, efficiency of packed bed membrane reactors have been successfully demonstrated. Thanks to protium isotope swamping, tritium bonded water can be recovered under the valuable Q{sub 2} form (Q = H, D or T) by means of isotope exchange reactions occurring on catalyst surface. The use of permselective Pd-based membrane allows withdrawal of reactions products all along the reactor, and thus limits reverse reaction rate to the benefit of the direct one (shift effect). The reactions kinetics, which are still little known or unknown, are generally assumed to be largely greater than the permeation ones so that thermodynamic equilibriums of isotope exchange reactions are generally assumed. This paper proposes a new phenomenological 2D model to represent catalytic membrane reactor behavior with the determination of gas effluents compositions. A good agreement was obtained between the simulation results and experimental measurements performed on a dedicated facility. Furthermore, the gas composition estimation permits to interpret unexpected behavior of the catalytic membrane reactor. In the next future, further sensitivity analysis will be performed to determine the limits of the model and a kinetics study will be conducted to assess the thermodynamic equilibrium of reactions.

  11. On the study of catalytic membrane reactor for water detritiation: Modeling approach

    International Nuclear Information System (INIS)

    Liger, Karine; Mascarade, Jérémy; Joulia, Xavier; Meyer, Xuan-Mi; Troulay, Michèle; Perrais, Christophe

    2016-01-01

    Highlights: • Experimental results for the conversion of tritiated water (using deuterium as a simulant of tritium) by means of a catalytic membrane reactor in view of tritium recovery. • Phenomenological 2D model to represent catalytic membrane reactor behavior including the determination of the compositions of gaseous effluents. • Good agreement between the simulation results and experimental measurements performed on the dedicated facility. • Explanation of the unexpected behavior of the catalytic membrane reactor by the modeling results and in particular the gas composition estimation. - Abstract: In the framework of tritium recovery from tritiated water, efficiency of packed bed membrane reactors have been successfully demonstrated. Thanks to protium isotope swamping, tritium bonded water can be recovered under the valuable Q_2 form (Q = H, D or T) by means of isotope exchange reactions occurring on catalyst surface. The use of permselective Pd-based membrane allows withdrawal of reactions products all along the reactor, and thus limits reverse reaction rate to the benefit of the direct one (shift effect). The reactions kinetics, which are still little known or unknown, are generally assumed to be largely greater than the permeation ones so that thermodynamic equilibriums of isotope exchange reactions are generally assumed. This paper proposes a new phenomenological 2D model to represent catalytic membrane reactor behavior with the determination of gas effluents compositions. A good agreement was obtained between the simulation results and experimental measurements performed on a dedicated facility. Furthermore, the gas composition estimation permits to interpret unexpected behavior of the catalytic membrane reactor. In the next future, further sensitivity analysis will be performed to determine the limits of the model and a kinetics study will be conducted to assess the thermodynamic equilibrium of reactions.

  12. 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

  13. Catalytic hydrotreating of lignin with water-soluble molybdenum catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Osmaa, A.; Johansson, A. (Technical Research Centre of Finland, Espoo (Finland). Lab. of Fuel and Process Technology)

    High yields (61% of the original lignin) of low molecular weight oil (84% of the oil eluted through GC) have been obtained by hydrotreating kraft pine lignin with a water-soluble molybdenum catalyst at 430[degree]C for 60 min. The main compounds in the product oil were phenols (8.7% of the original lignin), cyclohexanes (5.0%), benzenes (3.8%), naphthalenes (4.0%), and phenanthrenes (1.2%). The degree of hydrodeoxygenation was 98%. The quality (measured by GPC and GC) of the product was as good as when using more expensive solid NiMo-CR[sub 2]O[sub 3] catalysts. 30 refs., 6 tabs.

  14. The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water

    DEFF Research Database (Denmark)

    Nguyen, Thi Dieu Huyen; Maschietti, Marco; Åmand, Lars-Erik

    2014-01-01

    The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370 C and its effect on the process was investigated...... in a continuous flow (1 kg/h). The yields of water-soluble organics (WSO), bio-oil and char (dry lignin basis) were in the ranges of 5–11%, 69–87% and 16–22%, respectively. The bio-oil, being partially deoxygenated, exhibited higher carbon content and heat value, but lower sulphur content than lignin. The main 1...

  15. Photo catalytic BiFeO3 Nano fibrous Mats for Effective Water Treatment

    International Nuclear Information System (INIS)

    Shaibani, P.M.; Prashanthi, K.; Sohrabi, A.; Thundat, Th.

    2013-01-01

    One-dimensional BiFeO 3 (BFO) nano fibers fabricated by electro spinning of a solution of Nylon 6 /BFO followed by calcination were used for photo catalytic degradation of contaminants in water. The BFO fibers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM images of the as-spun samples demonstrated the successful production of nano fibers and the SEM images of the samples after calcination confirmed the integrity of the continuous BFO nano fibers. XRD analysis indicated the dominant presence of BFO phase throughout the calcinated nano fibers. Photo catalytic activity of the nano fibers and their application in water purification were investigated against 4-chloro phenol (4CP) as a model water contaminant. The results of the UV-Vis spectroscopy show the degradation of the 4CP by means of the photo catalytic activity of the BFO nano fibers. The kinetics of the photodegradation of 4CP is believed to be governed by a pseudo-first-order kinetics model.

  16. 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...

  17. Children with burns referred for child abuse evaluation: Burn characteristics and co-existent injuries.

    Science.gov (United States)

    Pawlik, Marie-Christin; Kemp, Alison; Maguire, Sabine; Nuttall, Diane; Feldman, Kenneth W; Lindberg, Daniel M

    2016-05-01

    Intentional burns represent a serious form of physical abuse that must be identified to protect children from further harm. This study is a retrospectively planned secondary analysis of the Examining Siblings To Recognize Abuse (ExSTRA) network data. Our objective was to describe the characteristics of burns injuries in children referred to Child Abuse Pediatricians (CAPs) in relation to the perceived likelihood of abuse. We furthermore compare the extent of diagnostic investigations undertaken in children referred to CAPs for burn injuries with those referred for other reasons. Within this dataset, 7% (215/2890) of children had burns. Children with burns were older than children with other injuries (median age 20 months vs. 10 months). Physical abuse was perceived as likely in 40.9% (88) and unlikely in 59.1% (127). Scalds accounted for 52.6% (113) and contact burns for 27.6% (60). Several characteristics of the history and burn injury were associated with a significantly higher perceived likelihood of abuse, including children with reported inflicted injury, absent or inadequate explanation, hot water as agent, immersion scald, a bilateral/symmetric burn pattern, total body surface area ≥10%, full thickness burns, and co-existent injuries. The rates of diagnostic testing were significantly lower in children with burns than other injuries, yet the yield of skeletal survey and hepatic transaminases testing were comparable between the two groups. This would imply that children referred to CAPs for burns warrant the same level of comprehensive investigations as those referred for other reasons. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Residential dynamics: the co-existence of formal and informal systems in Khartoum, Sudan

    CSIR Research Space (South Africa)

    Osman, A

    2010-05-01

    Full Text Available This paper looks at the residential dynamics in Khartoum, Sudan. Some patterns demonstrate that formal and informal systems co-exist and are mutually supportive. There are also particular spatial manifestations that have resulted from a unique socio...

  19. 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…

  20. 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...

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

    International Nuclear Information System (INIS)

    Hisam, A.; Rahman, M.; Kadir, E.; Ezam, N.; Khan, M.B.

    2014-01-01

    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)

  2. Synergetic Effects of Alcohol/Water Mixing on the Catalytic Reductive Fractionation of Poplar Wood

    Energy Technology Data Exchange (ETDEWEB)

    Renders, Tom; Van den Bosch, Sander; Vangeel, Thijs; Ennaert, Thijs; Koelewijn, Steven-Friso; Van den Bossche, Gil; Courtin, Christophe M.; Schutyser, Wouter; Sels, Bert F.

    2016-12-05

    One of the foremost challenges in lignocellulose conversion encompasses the integration of effective lignin valorization in current carbohydrate-oriented biorefinery schemes. Catalytic reductive fractionation (CRF) of lignocellulose offers a technology to simultaneously produce lignin-derived platform chemicals and a carbohydrate-enriched pulp via the combined action of lignin solvolysis and metal-catalyzed hydrogenolysis. Herein, the solvent (composition) plays a crucial role. In this contribution, we study the influence of alcohol/water mixtures by processing poplar sawdust in varying MeOH/water and EtOH/water blends. The results show particular effects that strongly depend on the applied water concentration. Low water concentrations enhance the removal of lignin from the biomass, while the majority of the carbohydrates are left untouched (scenario A). Contrarily, high water concentrations favor the solubilization of both hemicellulose and lignin, resulting in a more pure cellulosic residue (scenario B). For both scenarios, an evaluation was made to determine the most optimal solvent composition, based on two earlier introduced empirical efficiency descriptors (denoted LFDE and LFFE). According to these measures, 30 (A) and 70 vol % water (B) showed to be the optimal balance for both MeOH/water and EtOH/water mixtures. This successful implementation of alcohol/water mixtures allows operation under milder processing conditions in comparison to pure alcohol solvents, which is advantageous from an industrial point of view.

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

    International Nuclear Information System (INIS)

    Sung, K.W.; Na, J. W.; Cho, Y. H.; Chung, H. H.

    2000-01-01

    Experiments on aqueous TiO 2 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 TiO 2 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Sung, K.W.; Na, J. W.; Cho, Y. H.; Chung, H. H

    2000-01-01

    Experiments on aqueous TiO{sub 2} 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 TiO{sub 2} 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)

  5. A new type separation column for the water-hydrogen isotope catalytic exchange process

    International Nuclear Information System (INIS)

    Fedorchenko, O.A.; Alekseev, I.A.; Trenin, V.D.

    2001-01-01

    The catalytic water/hydrogen isotope exchange process is by right considered the most attractive for the solution a number of urgent problems of hydrogen isotope separation. A new type exchange reaction column is described and studied in details by computer simulation and with the help of McCabe-Thiele diagrams. It is shown that the new column in comparison with a traditional one needs less catalyst quantity and a smaller diameter for the solving of the same separation tasks. Generalized calculation data are presented in graphical form

  6. Three Co-Existing Sexually Transmitted Diseases in a Heterosexual Male Youth: A Case Report

    Directory of Open Access Journals (Sweden)

    Theetat M. Surawan

    2016-03-01

    Full Text Available Most sexually transmitted diseases (STDs are asymptomatic, leading to widespread underdiagnoses estimated at 50% or higher. The presence of one STD significantly indicates an individual’s sexual health risk since an STD contributes to the transmission and acquisition of other STDs, including human immunodeficiency virus (HIV infection. Multiple co-existing STDs, thus, further increase the susceptibility of acquiring and transmitting HIV by twofold or more. Therefore, the comprehensive STD prevention strategies play a major role in reducing the transmission of HIV infection. We report an interesting case of a heterosexual male youth who presented at dermatology clinic with three concurrent sexually transmitted diseases: gonococcal urethritis, genital wart, and late latent syphilis. The case demonstrated significant issues for appropriate approaches and management of multiple co-existing STDs. Also, it reinforced the necessity for STD counselling for the patient, his partners, and family.

  7. 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.

  8. Peaceful Co-existence in The Light of Objectives of Sharia’h

    Directory of Open Access Journals (Sweden)

    Shayuthy Abdul Manas

    2016-06-01

    Full Text Available The study focuses on clarifying the concept of peaceful coexistence, and its principles in the perspective of the “Maqasid Al-Shariah, (objectives of Islamic “Shariah” because, the most important purposes of “Maqasid AlShariah” are protection of soul, family, dignity and money. And also the establishment of security and peaceful life through the peaceful coexistence by following the basic foundations which are considered as important pillars of peaceful co-existence, these are nature, justice, freedom, and equality under the multiplicity of religions, different races and colors. Therefore, according to the interdependence between the objectives of “Shariah” and co-existence which is considered an important pillar of the social system, and the development of communities,the study focuses on highlighting some of the important problems that hinder the achievement of peaceful coexistence between Muslims and non-Muslims in the “Sri Lanka” due to the lack of knowledge about the reality of “Maqasid Al-Shariah” and its relationship to peaceful co-existence.

  9. 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.

  10. Co-existence of GM, conventional and organic crops in developing countries: Main debates and concerns.

    Science.gov (United States)

    Azadi, Hossein; Taube, Friedhelm; Taheri, Fatemeh

    2017-06-05

    The co-existence approach of GM crops with conventional agriculture and organic farming as a feasible agricultural farming system has recently been placed in the center of hot debates at the EU-level and become a source of anxiety in developing countries. The main promises of this approach is to ensure "food security" and "food safety" on the one hand, and to avoid the adventitious presence of GM crops in conventional and organic farming on the other, as well as to present concerns in many debates on implementing the approach in developing countries. Here, we discuss the main debates on ("what," "why," "who," "where," "which," and "how") applying this approach in developing countries and review the main considerations and tradeoffs in this regard. The paper concludes that a peaceful co-existence between GM, conventional, and organic farming is not easy but is still possible. The goal should be to implement rules that are well-established proportionately, efficiently and cost-effectively, using crop-case, farming system-based and should be biodiversity-focused ending up with "codes of good agricultural practice" for co-existence.

  11. Catalytic isotope exchange reaction between deuterium gas and water pre-adsorbed on platinum/alumina

    International Nuclear Information System (INIS)

    Iida, Itsuo; Kato, Junko; Tamaru, Kenzi.

    1976-01-01

    The catalytic isotope exchange reaction between deuterium gas and the water pre-adsorbed on Pt/Al 2 O 3 was studied. At reaction temperatures above 273 K, the exchange rate was proportional to the deuterium pressure and independent of the amount of adsorbed water, which suggests that the rate determining step is the supply of deuterium from the gas phase. Its apparent activation energy was 38 kJ mol -1 . Below freezing point of water, the kinetic behaviour was different from that above freezing point. At higher deuterium pressures the rate dropped abruptly at 273 K. Below the temperature the apparent activation energy was 54 kJ mol -1 and the exchange rate depended not on the deuterium pressure but on the amount of the pre-adsorbed water. At lower pressures, however, the kinetic behaviour was the same as the above 273 K, till the rate of the supply of deuterium from the gas phase exceeded the supply of hydrogen from adsorbed water to platinum surface. These results suggest that below 273 K the supply of hydrogen is markedly retarded, the state of the adsorbed water differing from that above 273 K. It was also demonstrated that when the adsorbed water is in the state of capillary condensation, the exchange rate becomes very small. (auth.)

  12. Endotoxin Removal from Water Using Heterogenus Catalytic Ozonation by Bone Char

    Directory of Open Access Journals (Sweden)

    Abas Rezaee

    2011-10-01

    Full Text Available The endotoxin is one of pollutants with lipopolysaccharide structure which release from gram negative bacteria and cyanobacters. The aim of this study was removal of endotoxin from water using catalytic ozonation by bone char. The endotoxin for experiments have extracted from Escherichia coli bacterium cell wall by Stefan and Jan method. Chromogenic limulus ambusite lysate method in 405-410 nm wave length was used for analysing of endotoxin. The ozone have analysed by potassium iodine method. Results: Results of the research shown endotoxin removal rates using heterogenous catalytic ozonation were 6.0 Eu/ml.min and 0.5 Eu/ml.min for grey bone char and white bone char, respectively. The efficency of the process was found eighty percent. Primary concentration of basic compounds had no effect on endotoxin removal rate. Therefore, endotoxin removal kinetic of reaction is a zero order reaction. This study revealed that ozonation process using bone char is more efficient than other proposed methods such as ozonation or chlorination and can be used successfully for endotoxin removal from water as a efficient method.

  13. Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

    Science.gov (United States)

    Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H; Navrotsky, Alexandra

    2013-05-28

    Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

  14. Green Synthesis and Catalytic Activity of Gold Nanoparticles Synthesized by Artemisia capillaris Water Extract

    Science.gov (United States)

    Lim, Soo Hyeon; Ahn, Eun-Young; Park, Youmie

    2016-10-01

    Gold nanoparticles were synthesized using a water extract of Artemisia capillaris (AC-AuNPs) under different extract concentrations, and their catalytic activity was evaluated in a 4-nitrophenol reduction reaction in the presence of sodium borohydride. The AC-AuNPs showed violet or wine colors with characteristic surface plasmon resonance bands at 534 543 nm that were dependent on the extract concentration. Spherical nanoparticles with an average size of 16.88 ± 5.47 29.93 ± 9.80 nm were observed by transmission electron microscopy. A blue shift in the maximum surface plasmon resonance was observed with increasing extract concentration. The face-centered cubic structure of AC-AuNPs was confirmed by high-resolution X-ray diffraction analysis. Based on phytochemical screening and Fourier transform infrared spectra, flavonoids, phenolic compounds, and amino acids present in the extract contributed to the reduction of Au ions to AC-AuNPs. The average size of the AC-AuNPs decreased as the extract concentration during the synthesis was increased. Higher 4-nitrophenol reduction reaction rate constants were observed for smaller sizes. The extract in the AC-AuNPs was removed by centrifugation to investigate the effect of the extract in the reduction reaction. Interestingly, the removal of extracts greatly enhanced their catalytic activity by up to 50.4 %. The proposed experimental method, which uses simple centrifugation, can be applied to other metallic nanoparticles that are green synthesized with plant extracts to enhance their catalytic activity.

  15. 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.

  16. A rare challenging case of co-existent craniopharyngioma, acromegaly and squamous cell lung cancer

    Directory of Open Access Journals (Sweden)

    Athanasios Fountas

    2018-04-01

    Full Text Available Co-existence of craniopharyngioma and acromegaly has been very rarely reported. A 65-year-old man presented with visual deterioration, fatigue and frontal headaches. Magnetic resonance imaging revealed a suprasellar heterogeneous, mainly cystic, 1.9 × 2 × 1.9 cm mass compressing the optic chiasm and expanding to the third ventricle; the findings were consistent with a craniopharyngioma. Pituitary hormone profile showed hypogonadotropic hypogonadism, mildly elevated prolactin, increased insulin-like growth factor 1 (IGF-1 and normal thyroid function and cortisol reserve. The patient had transsphenoidal surgery and pathology of the specimen was diagnostic of adamantinomatous craniopharyngioma. Post-operatively, he had diabetes insipidus, hypogonadotropic hypogonadism and adrenocorticotropic hormone and thyroid-stimulating hormone deficiency. Despite the hypopituitarism, his IGF-1 levels remained elevated and subsequent oral glucose tolerance test did not show complete growth hormone (GH suppression. Further review of the pre-operative imaging revealed a 12 × 4 mm pituitary adenoma close to the right carotid artery and no signs of pituitary hyperplasia. At that time, he was also diagnosed with squamous cell carcinoma of the left upper lung lobe finally managed with radical radiotherapy. Treatment with long-acting somatostatin analogue was initiated leading to biochemical control of the acromegaly. Latest imaging has shown no evidence of craniopharyngioma regrowth and stable adenoma. This is a unique case report of co-existence of craniopharyngioma, acromegaly and squamous lung cell carcinoma that highlights diagnostic and management challenges. Potential effects of the GH hypersecretion on the co-existent tumours of this patient are also briefly discussed.

  17. A rare challenging case of co-existent craniopharyngioma, acromegaly and squamous cell lung cancer.

    Science.gov (United States)

    Fountas, Athanasios; Chai, Shu Teng; Ayuk, John; Gittoes, Neil; Chavda, Swarupsinh; Karavitaki, Niki

    2018-01-01

    Co-existence of craniopharyngioma and acromegaly has been very rarely reported. A 65-year-old man presented with visual deterioration, fatigue and frontal headaches. Magnetic resonance imaging revealed a suprasellar heterogeneous, mainly cystic, 1.9 × 2 × 1.9 cm mass compressing the optic chiasm and expanding to the third ventricle; the findings were consistent with a craniopharyngioma. Pituitary hormone profile showed hypogonadotropic hypogonadism, mildly elevated prolactin, increased insulin-like growth factor 1 (IGF-1) and normal thyroid function and cortisol reserve. The patient had transsphenoidal surgery and pathology of the specimen was diagnostic of adamantinomatous craniopharyngioma. Post-operatively, he had diabetes insipidus, hypogonadotropic hypogonadism and adrenocorticotropic hormone and thyroid-stimulating hormone deficiency. Despite the hypopituitarism, his IGF-1 levels remained elevated and subsequent oral glucose tolerance test did not show complete growth hormone (GH) suppression. Further review of the pre-operative imaging revealed a 12 × 4 mm pituitary adenoma close to the right carotid artery and no signs of pituitary hyperplasia. At that time, he was also diagnosed with squamous cell carcinoma of the left upper lung lobe finally managed with radical radiotherapy. Treatment with long-acting somatostatin analogue was initiated leading to biochemical control of the acromegaly. Latest imaging has shown no evidence of craniopharyngioma regrowth and stable adenoma. This is a unique case report of co-existence of craniopharyngioma, acromegaly and squamous lung cell carcinoma that highlights diagnostic and management challenges. Potential effects of the GH hypersecretion on the co-existent tumours of this patient are also briefly discussed. Although an extremely rare clinical scenario, craniopharyngioma and acromegaly can co-exist; aetiopathogenic link between these two conditions is unlikely.Meticulous review of unexpected

  18. Fungal communities in wheat grain show significant co-existence patterns among species

    DEFF Research Database (Denmark)

    Nicolaisen, M.; Justesen, A. F.; Knorr, K.

    2014-01-01

    identified as ‘core’ OTUs as they were found in all or almost all samples and accounted for almost 99 % of all sequences. The remaining OTUs were only sporadically found and only in small amounts. Cluster and factor analyses showed patterns of co-existence among the core species. Cluster analysis grouped...... the 21 core OTUs into three clusters: cluster 1 consisting of saprotrophs, cluster 2 consisting mainly of yeasts and saprotrophs and cluster 3 consisting of wheat pathogens. Principal component extraction showed that the Fusarium graminearum group was inversely related to OTUs of clusters 1 and 2....

  19. Atomistic structure of cobalt-phosphate nanoparticles for catalytic water oxidation.

    Science.gov (United States)

    Hu, Xiao Liang; Piccinin, Simone; Laio, Alessandro; Fabris, Stefano

    2012-12-21

    Solar-driven water splitting is a key photochemical reaction that underpins the feasible and sustainable production of solar fuels. An amorphous cobalt-phosphate catalyst (Co-Pi) based on earth-abundant elements has been recently reported to efficiently promote water oxidation to protons and dioxygen, a main bottleneck for the overall process. The structure of this material remains largely unknown. We here exploit ab initio and classical atomistic simulations combined with metadynamics to build a realistic and statistically meaningful model of Co-Pi nanoparticles. We demonstrate the emergence and stability of molecular-size ordered crystallites in nanoparticles initially formed by a disordered Co-O network and phosphate groups. The stable crystallites consist of bis-oxo-bridged Co centers that assemble into layered structures (edge-sharing CoO(6) octahedra) as well as in corner- and face-sharing cubane units. These layered and cubane motifs coexist in the crystallites, which always incorporate disordered phosphate groups at the edges. Our computational nanoparticles, although limited in size to ~1 nm, can contain more than one crystallite and incorporate up to 18 Co centers in the cubane/layered structures. The crystallites are structurally stable up to high temperatures. We simulate the extended X-ray absorption fine structure (EXAFS) of our nanoparticles. Those containing several complete and incomplete cubane motifs-which are believed to be essential for the catalytic activity-display a very good agreement with the experimental EXAFS spectra of Co-Pi grains. We propose that the crystallites in our nanoparticles are reliable structural models of the Co-Pi catalyst surface. They will be useful to reveal the origin of the catalytic efficiency of these novel water-oxidation catalysts.

  20. 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)

  1. The Principle(s) of Co-existence in the Market for GMOs in Europe: Social, Economic and Legal Avenues

    NARCIS (Netherlands)

    Purnhagen, K.; Wesseler, J.H.H.

    2016-01-01

    The European policy of co-existence for GMOs follows a number of well-established social, economic and legal principles. Applying these principles in practice has resulted in a complex “rag rug” of co-existence policies in Europe. This rag rug makes enforcement of these principles difficult, at

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

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar Suman

    2016-01-01

    Full Text Available 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.

  3. Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions.

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-09-27

    Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs.

  4. A case of desmoid tumor co-existing with recurrent squamous cell carcinoma in the larynx.

    Science.gov (United States)

    Shinohara, Shogo; Suehiro, Atsushi; Kikuchi, Masahiro; Harada, Hiroyuki; Kishimoto, Ippei; Imai, Yukihiro

    2017-06-01

    Extra-abdominal desmoid tumor, also known as aggressive fibromatosis, has aggressive behavior with local infiltration and tendency for recurrence. Though head and neck is reported to be one of the most common sites, a desmoid tumor in the larynx is extremely rare. A 67-year-old male visited our hospital with prolonged hoarseness and received laryngo-microsurgery with the diagnosis of laryngeal polyp. After the operation, he eventually developed a laryngeal squamous cell carcinoma with papilloma, confirmed by second laryngo-microsurgery and received radiation therapy. After the third laryngo-microsurgery to remove residual papilloma, white irregular mass appeared on the right vocal cord and grew rapidly beneath the glottis, causing dyspnea. After 2 additional laryngo-microsurgeries, he was diagnosed having the dermoid tumor co-existing with recurrent squamous cell carcinoma. He underwent near-total laryngectomy and is currently alive without disease, speaking using a vocal shunt. Only five cases of the desmoid tumors arising in the adult larynx have been reported in the English literature. In this case, repeated surgery and radiation were suspected as the causes. Also, the present report is the first to describe desmoid tumor co-existing with recurrent squamous cell carcinoma in the larynx. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

    Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs. PMID:28904262

  6. 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.

  7. 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

  8. 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

  9. Measurement of capacity coefficient of inclined liquid phase catalytic exchange column for tritiated water processing

    International Nuclear Information System (INIS)

    Yamai, Hideki; Konishi, Satoshi; Yamanishi, Toshihiko; Okuno, Kenji

    1994-01-01

    Liquid phase catalytic exchange (LPCE) is effective method for enrichment and removal of tritium from tritiated water. Capacity coefficients of operating LPCE column that are essential to evaluate column performance were measured. Experiments were performed with short catalyst packed columns and effect of inclination was studied. Method for evaluation of capacity coefficients was established from measurement of isotope concentration of liquid, vapor, gas phases at the two ends of the column. The capacity coefficients were measured under various superficial gas velocities. Feasibility study of helical columns with roughened inner surface was performed with short inclined columns. The column performance was not strongly affected by the inclination. The result indicates technological feasibility of helical LPCE column, that is expected to have operation stability and reduced height

  10. Familiality of co-existing ADHD and tic disorders: evidence from a large sibling study

    Directory of Open Access Journals (Sweden)

    Veit Roessner

    2016-07-01

    Full Text Available AbstractBackground: 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

  11. Novel Fe-Pd/SiO2 catalytic materials for degradation of chlorinated organic compounds in water

    Science.gov (United States)

    Novel reactive materials for catalytic degradation of chlorinated organic compounds in water at ambient conditions have been prepared on the basis of silica-supported Pd-Fe nanoparticles. Nanoscale Fe-Pd particles were synthesized inside porous silica supports using (NH4

  12. Anaesthetic management of the child with co-existing pulmonary disease.

    Science.gov (United States)

    Lauer, R; Vadi, M; Mason, L

    2012-12-01

    Children with co-existing pulmonary disease have a wide range of clinical manifestations with significant implications for anaesthetists. Although there are a number of pulmonary diseases in children, this review focuses on two of the most common pulmonary disorders, asthma and bronchopulmonary dysplasia (BPD). These diseases share the physiology of bronchoconstriction and variably decreased flow in the airways, but also have unique physiological consequences. The anaesthetist can make a difference in outcomes with proper preoperative evaluation and appropriate preparation for surgery in the context of a team approach to perioperative care with implementation of a stepwise approach to disease management. An understanding of the importance of minimizing the risk for bronchoconstriction and having the tools at hand to treat it when necessary is paramount in the care of these patients. Unique challenges exist in the management of pulmonary hypertension in BPD patients. This review covers medical treatment, intraoperative management, and postoperative care for both patient populations.

  13. 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.

  14. Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid water

    Science.gov (United States)

    Cortright, R. D.; Davda, R. R.; Dumesic, J. A.

    2002-08-01

    Concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. Hydrogen is currently derived from nonrenewable natural gas and petroleum, but could in principle be generated from renewable resources such as biomass or water. However, efficient hydrogen production from water remains difficult and technologies for generating hydrogen from biomass, such as enzymatic decomposition of sugars, steam-reforming of bio-oils and gasification, suffer from low hydrogen production rates and/or complex processing requirements. Here we demonstrate that hydrogen can be produced from sugars and alcohols at temperatures near 500K in a single-reactor aqueous-phase reforming process using a platinum-based catalyst. We are able to convert glucose-which makes up the major energy reserves in plants and animals-to hydrogen and gaseous alkanes, with hydrogen constituting 50% of the products. We find that the selectivity for hydrogen production increases when we use molecules that are more reduced than sugars, with ethylene glycol and methanol being almost completely converted into hydrogen and carbon dioxide. These findings suggest that catalytic aqueous-phase reforming might prove useful for the generation of hydrogen-rich fuel gas from carbohydrates extracted from renewable biomass and biomass waste streams.

  15. 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.)

  16. Catalytic effect of different reactor materials under subcritical water conditions: decarboxylation of cysteic acid into taurine

    Science.gov (United States)

    Faisal, M.

    2018-03-01

    In order to understand the influence of reactor materials on the catalytic effect for a particular reaction, the decomposition of cysteic acid from Ni/Fe-based alloy reactors under subcritical water conditions was examined. Experiments were carried out in three batch reactors made of Inconel 625, Hastelloy C-22 and SUS 316 over temperatures of 200 to 300 °C. The highest amount of eluted metals was found for SUS 316. The results demonstrated that reactor materials contribute to the resulting product. Under the tested conditions, cysteic acid decomposes readily with SUS 316. However, the Ni-based materials (Inconel 625 and Hastelloy C-22) show better resistance to metal elution. It was found that among the materials used in this work, SUS 316 gave the highest reaction rate constant of 0.1934 s‑1. The same results were obtained at temperatures of 260 and 300 °C. Investigation of the Arrhenius activation energy revealed that the highest activation energy was for Hastelloy C-22 (109 kJ/mol), followed by Inconel 625 (90 kJ/mol) and SUS 316 (70 kJ/mol). The decomposition rate of cysteic acid was found to follow the results for the trend of the eluted metals. Therefore, it can be concluded that the decomposition of cysteic acid was catalyzed by the elution of heavy metals from the surface of the reactor. The highest amount of taurine from the decarboxylation of cysteic acid was obtained from SUS 316.

  17. Co-existence of freshwater and marine T4-like myoviruses in a typical subtropical estuary.

    Science.gov (United States)

    Liu, Lu; Cai, Lanlan; Zhang, Rui

    2017-11-01

    Viruses are the most abundant biological entities on Earth and play an important role in microbial community dynamics and biogeochemical cycling, yet their ecological characteristics in estuarine ecosystems are unclear. Here, virioplankton communities in a typical subtropical estuary, the Jiulong River estuary (JRE) in China, were investigated. The abundance of virioplankton ranged from 1.01 ± 0.05 × 107 to 1.62 ± 0.09 × 107 particles mL-1 in JRE, and the population size of viruses was correlated with temperature and nutrient levels. Three tailed viral morphotypes (myovirus, siphovirus and podovirus) were observed. Phylogenetic analysis showed that most of the g23 sequences in the JRE fell into three previously established groups (Marine, Paddy and Lake Groups) and two potential Estuary Groups. This demonstrates the co-existence of typical freshwater and marine T4-like myoviruses in the estuarine ecosystem, suggesting the movement of viruses and their hosts among biomes. Additionally, the spatial variation of g23 sequences suggests a geographic distribution pattern of T4-like myoviruses in the JRE, which might be shaped by the environmental gradient and/or their host distribution. These results provide valuable insights into the abundance, diversity and distribution patterns of virioplankton, as well as the factors influencing them, in subtropical estuarine ecosystems. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. The Co-Existence of Myasthenia Gravis in Patients with Myositis: A Case Series

    Science.gov (United States)

    Paik, Julie J.; Corse, Andrea M.; Mammen, Andrew L.

    2014-01-01

    Objective Myositis and myasthenia gravis (MG) are both autoimmune disorders presenting with muscle weakness. Rarely, they occur simultaneously in the same patient. Since the management of myasthenia gravis differs from that of myositis, it is important to recognize when patients have both diseases. We reviewed the cases of 6 patients with both myositis and MG to identify clinical features that suggest the possibility of co-existing MG in myositis patients. Methods We identified 6 patients with dermatomyositis or polymyositis and MG. We reviewed their medical records to assess their clinical presentations, laboratory findings, and electrophysiological features. Results All 6 patients had definite dermatomyositis or polymyositis by the criteria of Bohan and Peter as well as electrophysiologic and/or serologic confirmation of MG. Among overlap patients, 5/6 (83%) had bulbar weakness, 2/6 (33%) had ptosis, and 1/6 (17%) had diplopia. Fatigable weakness was noted by 5/6 (83%) patients. Treatment with pyridostigmine improved symptoms in 5/6 (83%). High dose steroids were associated with worsening weakness in 2/6 (33%) patients. Conclusions Prominent bulbar symptoms, ptosis, diplopia, and fatigable weakness should suggest the possibility of MG in patients with myositis. A suspicion of MG may be confirmed through appropriate electrophysiologic and laboratory testing. In those with myositis-MG overlap, high dose steroids may exacerbate symptoms and pryidostigmine may play an important therapeutic role. PMID:24412588

  19. Nanoparticle interactions with co-existing contaminants: joint toxicity, bioaccumulation and risk.

    Science.gov (United States)

    Deng, Rui; Lin, Daohui; Zhu, Lizhong; Majumdar, Sanghamitra; White, Jason C; Gardea-Torresdey, Jorge L; Xing, Baoshan

    2017-06-01

    With their growing production and application, engineered nanoparticles (NPs) are increasingly discharged into the environment. The released NPs can potentially interact with pre-existing contaminants, leading to biological effects (bioaccumulation and/or toxicity) that are poorly understood. Most studies on NPs focus on single analyte exposure; the existing literature on joint toxicity of NPs and co-existing contaminants is rather limited but beginning to develop rapidly. This is the first review paper evaluating the current state of knowledge regarding the joint effects of NPs and co-contaminants. Here, we review: (1) methods for investigating and evaluating joint effects of NPs and co-contaminants; (2) simultaneous toxicities from NPs co-exposed with organic contaminants, metal/metalloid ions, dissolved organic matter (DOM), inorganic ligands and additional NPs; and (3) the influence of NPs co-exposure on the bioaccumulation of organic contaminants and heavy metal ions, as well as the influence of contaminants on NPs bioaccumulation. In addition, future research needs are discussed so as to better understand risk associated with NPs-contaminant co-exposure.

  20. A Mobile Asset Tracking System Architecture under Mobile-Stationary Co-Existing WSNs

    Science.gov (United States)

    Kim, Tae Hyon; Jo, Hyeong Gon; Lee, Jae Shin; Kang, Soon Ju

    2012-01-01

    The tracking of multiple wireless mobile nodes is not easy with current legacy WSN technologies, due to their inherent technical complexity, especially when heavy traffic and frequent movement of mobile nodes are encountered. To enable mobile asset tracking under these legacy WSN systems, it is necessary to design a specific system architecture that can manage numerous mobile nodes attached to mobile assets. In this paper, we present a practical system architecture including a communication protocol, a three-tier network, and server-side middleware for mobile asset tracking in legacy WSNs consisting of mobile-stationary co-existing infrastructures, and we prove the functionality of this architecture through careful evaluation in a test bed. Evaluation was carried out in a microwave anechoic chamber as well as on a straight road near our office. We evaluated communication mobility performance between mobile and stationary nodes, location-awareness performance, system stability under numerous mobile node conditions, and the successful packet transfer rate according to the speed of the mobile nodes. The results indicate that the proposed architecture is sufficiently robust for application in realistic mobile asset tracking services that require a large number of mobile nodes. PMID:23242277

  1. 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.

  2. A Mobile Asset Tracking System Architecture under Mobile-Stationary Co-Existing WSNs

    Directory of Open Access Journals (Sweden)

    Soon Ju Kang

    2012-12-01

    Full Text Available The tracking of multiple wireless mobile nodes is not easy with current legacy WSN technologies, due to their inherent technical complexity, especially when heavy traffic and frequent movement of mobile nodes are encountered. To enable mobile asset tracking under these legacy WSN systems, it is necessary to design a specific system architecture that can manage numerous mobile nodes attached to mobile assets. In this paper, we present a practical system architecture including a communication protocol, a three-tier network, and server-side middleware for mobile asset tracking in legacy WSNs consisting of mobile-stationary co-existing infrastructures, and we prove the functionality of this architecture through careful evaluation in a test bed. Evaluation was carried out in a microwave anechoic chamber as well as on a straight road near our office. We evaluated communication mobility performance between mobile and stationary nodes, location-awareness performance, system stability under numerous mobile node conditions, and the successful packet transfer rate according to the speed of the mobile nodes. The results indicate that the proposed architecture is sufficiently robust for application in realistic mobile asset tracking services that require a large number of mobile nodes.

  3. 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.

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

    International Nuclear Information System (INIS)

    Mascarade, Jeremy

    2015-01-01

    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 Q 2 O+H 2 ↔H 2 O+Q 2 (Q=H,D or T) and selective permeation of Q 2 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

  5. 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

  6. alpha,beta-unsaturated 2-acyl imidazoles as a practical class of dienophiles for the DNA-Based catalytic asymmetric diels-alder reaction in water

    NARCIS (Netherlands)

    Boersma, A.J.; Feringa, B.L.; Roelfes, G.

    2007-01-01

    alpha,beta-Unsaturated 2-acyl imidazoles are a novel and practical class of dienophiles for the DNA-based catalytic asymmetric Diels-Alder reaction in water. The Diels-Alder products are obtained with very high diastereoselectivities and enantioselectivities in the range of 83-98%. The catalytic

  7. One Year in the Lower St. Lawrence Estuary: Feeding Niche Separation of Two Co-existing Krill Species

    Science.gov (United States)

    Winkler, G.; Cabrol, J.; Sage, R.; Nozais, C.; Tremblay, R.; Starr, M.

    2016-02-01

    The lower St. Lawrence estuary (LSLE) is influenced by river discharge and saltwater inflow. Together with arctic water inflow and ice cover in winter a strong stratification occurs resulting in a cold intermediate layer (CIL) from spring to autumn. This stratification provides thermal habitats. Here, we focus on two krill species Thysanoessa raschii and Meganyctiphanes norvegica that aggregate in the CIL and the warmer deep water layer, respectively. Both species are known to migrate into the surface layer to feed and thus transfering energy through the food web by linking lower with higher trophic levels. However, their specific feeding biology and trophic interactions are poorly understood. We tested the following hypotheses: (1) the diets vary throughout the season depending on food availability, (2) similar to thermal habitat separation, trophic niche separation between T. raschii and M. norvegica occurs, characterized by herbivory in T. raschii and carnivory in M. norvegica. Trophic position and feeding behavior of theses krill populations were monitored throughout one year 2014-2015 using a stable isotope approach. The two species showed a seasonal shift in their trophic position being on a higher trophic level in summer than in spring and autumn, which did not correspond to phytoplankton or zooplankton availability. Within the trophic space of carbon and nitrogen stable isotopes M. norvegica showed a relatively stable position, whereas T. raschii covered a much larger space throughout the year. M. norvegica was always positioned at a higher trophic level than T. raschii. Results of a stable isotope mixing model (SIAR) revealed 50% phytoplankton and 50% copepods in the diet of M. norvegica, while T. raschii showed a higher proportion of ca. 70% phytoplankton in its diet. Both species exploited several trophic levels, but in different proportions, thereby minimizing diet overlap, suggesting a further mechanism to enhance stable co-existence of these krill

  8. Experimental Investigation in Order to Determine Catalytic Package Performances in Case of Tritium Transfer from Water to Gas

    International Nuclear Information System (INIS)

    Bornea, Anisia; Peculea, M.; Zamfirache, M.; Varlam, Carmen

    2005-01-01

    The processes for hydrogen isotope's separation are very important for nuclear technology. One of the most important processes for tritium separation, is the catalyst isotope exchange water-hydrogen.Our catalytic package consists of Romanian patented catalysts with platinum on charcoal and polytetrafluoretylene (Pt/C/PTFE) and the ordered Romanian patented package B7 type. The catalytic package was tested in an isotope exchange facility for water detritiation at the Experimental Pilot Plant from ICIT Rm.Valcea.In a column of isotope exchange tritium is transferred from liquid phase (tritiated heavy water) in gaseous phase (hydrogen). In the experimental set-up, which was used, the column of catalytic isotope exchange is filled with successive layers of catalyst and ordered package. The catalyst consists of 95.5 wt.% of PTFE, 4.1 wt. % of carbon and 0.40 wt. % of platinum and was of Raschig rings 10 x 10 x 2 mm. The ordered package was B7 type consists of wire mesh phosphor bronze 4 x 1 wire and the mesh dimension is 0.18 x 0.48 mm.We analyzed the transfer phenomena of tritium from liquid to gaseous phase, in this system.The mass transfer coefficient which characterized the isotopic exchange on the package, were determined as function of experimental parameters

  9. Amine binding and oxidation at the catalytic site for photosynthetic water oxidation

    Science.gov (United States)

    Ouellette, Anthony J. A.; Anderson, Lorraine B.; Barry, Bridgette A.

    1998-01-01

    Photosynthetic water oxidation occurs at the Mn-containing catalytic site of photosystem II (PSII). By the use of 14C-labeled amines and SDS-denaturing PAGE, covalent adducts derived from primary amines and the PSII subunits, CP47, D2/D1, and the Mn-stabilizing protein, can be observed. When PSII contains the 18- and 24-kDa extrinsic proteins, which restrict access to the active site, no 14C labeling is obtained. NaCl, but not Na2SO4, competes with 14C labeling in Mn-containing PSII preparations, and the concentration dependence of this competition parallels the activation of oxygen evolution. Formation of 14C-labeled adducts is observed in the presence or in the absence of a functional manganese cluster. However, no significant Cl− effect on 14C labeling is observed in the absence of the Mn cluster. Isolation and quantitation of the 14C-labeled aldehyde product, produced from [14C]benzylamine, gives yields of 1.8 ± 0.3 mol/mol PSII and 2.9 ± 0.2 mol/mol in Mn-containing and Mn-depleted PSII, respectively. The corresponding specific activities are 0.40 ± 0.07 μmol(μmol PSII-hr)−1 and 0.64 ± 0.04 μmol(μmol PSII-hr)−1. Cl− suppresses the production of [14C]benzaldehyde in Mn-containing PSII, but does not suppress the production in Mn-depleted preparations. Control experiments show that these oxidation reactions do not involve the redox-active tyrosines, D and Z. Our results suggest the presence of one or more activated carbonyl groups in protein subunits that form the active site of PSII. PMID:9482863

  10. Catalytic membrane reactors for tritium recovery from tritiated water in the ITER fuel cycle

    International Nuclear Information System (INIS)

    Tosti, S.; Violante, V.; Basile, A.; Chiappetta, G.; Castelli, S.; De Francesco, M.; Scaglione, S.; Sarto, F.

    2000-01-01

    Palladium and palladium-silver permeators have been obtained by coating porous ceramic tubes with a thin metal layer. Three coating techniques have been studied and characterized: chemical electroless deposition (PdAg film thickness of 10 μm), ion sputtering (about 1 μm) and rolling of thin metal sheets (50 μm). The Pd-ceramic membranes have been used for manufacturing catalytic membrane reactors (CMR) for hydrogen and its isotopes recovering and purifying. These composite membranes and the CMR have been studied and developed for a closed-loop process with reference to the design requirements of the international thermonuclear experimental reactor (ITER) blanket tritium recovery system in the enhanced performance phase of operation. The membranes and CMR have been tested in a pilot plant equipped with temperature, pressure and flow-rate on-line measuring and controlling devices. The conversion value for the water gas shift reaction in the CMR has been measured close to 100% (always above the equilibrium one, 80% at 350 deg. C): the effect of the membrane is very clear since the reaction is moved towards the products because of the continuous hydrogen separation. The rolled thin film membranes have separated the hydrogen from other gases with a complete selectivity and exhibited a slightly larger mass transfer resistance with respect to the electroless membranes. Preliminary tests on the sputtered membranes have also been carried out with a promising performance. Considerations on the use of different palladium alloy in order to improve the performances of the membranes in terms of permeation flux and mechanical strength, such as palladium/yttrium, are also reported

  11. Removal of Humic Substances from Water by Advanced Oxidation Process Using UV/TiO2 Photo Catalytic Technology

    Directory of Open Access Journals (Sweden)

    Hassan Khorsandi

    2009-01-01

    Full Text Available Humic substances have been known as precursors to disinfection by-products. Because conventional treatment processes cannot meet disinfection by-product standards, novel methods have been increasingly applied for the removal of disinfection by-products precursors. The UV/TiO2 process is one of the advanced oxidation processes using the photocatalytic technology. The most important advantages of this process are its stability and high efficiency removal. The present study aims to investigate the effect of UV/TiO2 photo-catalytic technology on removal of humic substances. The study was conducted in a lab-scale batch photo-catalytic reactor using the interval experimental method. The UV irradiation source was a low pressure mercury vapor lamp 55w that was axially centered and was immersed in a humic acids solution within a stainless steel tubular 2.8 L reaction volume. Each of the samples taken from the UV/TiO2 process and other processes studied were analyzed for their dissolved organic carbon, UV absorbance at 254nm, and specific UV254 absorbance. The results indicated the high efficiency of the UV/TiO2 photo-catalytic process (TiO2=0.1 g/L and pH=5, compared to other processes, for humic substances removal from water sources. The process was also found to be capable of decreasing the initial dissolved organic carbon from 5 to 0.394 mg/L. The Specific UV254 Absorbance of 2.79 L/mg.m was attained after 1.5 hr. under photo-catalytic first order reaction (k= 0.0267 min-1. It may be concluded that the UV/TiO2 process can provide desirable drinking water quality in terms of humic substance content.

  12. Effect of NO2 and water on the catalytic oxidation of soot

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Grunwaldt, Jan-Dierk; Jensen, Anker Degn

    2017-01-01

    The influence of adding NO2 to 10 vol% O2/N2 on non-catalytic soot oxidation and soot oxidation in intimate or loose contact with a catalyst has been investigated. In non-catalytic soot oxidation the oxidation rate is increased significantly at lower temperatures by NO2. For soot oxidation in tig...... exhibited a volcano-curve dependence on the heat of oxygen chemisorption, and among the tested pure metals and oxides Cr2O3 was the most active catalyst. Further improvements were achieved with a FeaCrbOx binary oxide catalyst....

  13. Informal waste collection and its co-existence with the formal waste sector: The case of Kampala, Uganda

    NARCIS (Netherlands)

    Katusiimeh, M.W.; Burger, C.P.J.; Mol, A.P.J.

    2013-01-01

    We analyze how the informal collectors and the formal sector co-exist in solid waste collection in Kampala. We rely on household surveys and a small survey among the informal collectors in Kampala. Findings suggest that informal collectors play a substantial role in the first stage – collecting

  14. Co-Existence of Tuberous Sclerosis and the Fanconi Syndrome in Two Saudi Male Siblings: Report on Two Cases

    International Nuclear Information System (INIS)

    Al-Hwiesh, Abdulla K.; Al-Mueilo, Samir H.; Saeed, Ibrahim; Barak, Infal H.; Al-Muhanna, Fahd A.

    2005-01-01

    In this report, we present two cases of familial tuberous sclerosis co-existing with the Fanconi Syndrome. Both cases presented with history of failure to thrive and mental retardation associated with hypokalemic metabolic acidosis. To our knowledge, the association between tuberous sclerosis and the Fanconi Syndrome has not been reported previously. (author)

  15. From the wound to the bench : exoproteome interplay between wound-colonizing Staphylococcus aureus strains and co-existing bacteria

    NARCIS (Netherlands)

    García-Pérez, Andrea N.; de Jong, Anne; Junker, Sabryna; Becher, Dörte; Chlebowicz, Monika A.; Duipmans, José C.; Jonkman, Marcel F.; van Dijl, Jan Maarten

    2018-01-01

    Wound-colonizing microorganisms can form complex and dynamic polymicrobial communities where pathogens and commensals may co-exist, cooperate or compete with each other. The present study was aimed at identifying possible interactions between different bacteria isolated from the same chronic wound

  16. Surface-Enhanced Separation of Water from Hydrocarbons: Potential Dewatering Membranes for the Catalytic Fast Pyrolysis of Pine Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Engtrakul, Chaiwat; Hu, Michael Z.; Bischoff, Brian L.; Jang, Gyoung G.

    2016-10-20

    The impact of surface-selective coatings on water permeation through a membrane when exposed to catalytic fast pyrolysis (CFP) vapor products was studied by tailoring the surface properties of the membrane coating from superhydrophilic to superhydrophobic. Our approach used high-performance architectured surface-selective (HiPAS) membranes that were inserted after a CFP reactor. At this insertion point, the inner wall surface of a tubular membrane was exposed to a mixture of water and upgraded product vapors, including light gases and deoxygenated hydrocarbons. Under proper membrane operating conditions, a high selectivity for water over one-ring upgraded biomass pyrolysis hydrocarbons was observed as a result of a surface-enhanced capillary condensation process. Owing to this surface-enhanced effect, HiPAS membranes have the potential to enable high flux separations, suggesting that water can be selectively removed from the CFP product vapors.

  17. 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

  18. 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.

  19. Investigation of catalytic oxidation of diamond by water vapor and carbon dioxide in the presence of alkali melts of some rare earth oxides

    International Nuclear Information System (INIS)

    Kulakova, I.I.; Rudenko, A.P.; Sulejmenova, A.S.; Tolstopyatova, A.A.

    1978-01-01

    The results of an investigation of the catalytic oxydation of diamond by carbon dioxide and water vapors at 906 deg C in the presence of melts of some rare earth oxides in potassium hydroxide are given. The ion La 3+ was shown to possess the most catalytic activity. The earlier proposed mechanisms of the diamond oxidation by CO 2 and H 2 O were corroborated. The ions of rare earth elements were found to accelerate the different stages of the process

  20. ADHD in girls and boys – gender differences in co-existing symptoms and executive function measures

    OpenAIRE

    Skogli, Erik Winther; Teicher, Martin H; Andersen, Per Normann; Hovik, Kjell Tore; Øie, Merete

    2013-01-01

    Background: ADHD is diagnosed and treated more often in males than in females. Research on gender differences suggests that girls may be consistently underidentified and underdiagnosed because of differences in the expression of the disorder among boys and girls. One aim of the present study was to assess in a clinical sample of medication naïve boys and girls with ADHD, whether there were significant gender x diagnosis interactions in co-existing symptom severity and executive function (EF) ...

  1. COMPETITIVE ADVANTAGES OF POLISH ORGANIC SECTOR IN LIGHT OF CO-EXISTANCE BETWEEN GMO AND NON-GM PRODUCTS

    OpenAIRE

    Maciejczak, Mariusz

    2008-01-01

    The perfect segregation of the different agricultural production types, namely conventional, organic or based on genetically modified organisms is not possible in practice. But the side by side functioning of this systems in agricultural production and further on of the products on the shelves requires suitable measures during cultivation, harvest, transport, storage, and processing to ensure co-existence. Consumers, food and feed industry, as well as wholesalers and retailers in European Uni...

  2. Co-existence of Phenylketonuria and Fabry disease on a 3 year-old boy: case report

    Directory of Open Access Journals (Sweden)

    Bonapace Giuseppe

    2010-05-01

    Full Text Available Abstract Background The co-existence of two genetically distinct metabolic disorders in the same patient has rarely been reported. Phenylketonuria (PKU is an inborn error of the metabolism resulting from a phenylalanine hydroxylase deficiency. Fabry disease (FD is an X-linked lysosomal storage disorder due to a deficiency of the enzyme alpha-galactosidase A. Case presentation We report a case of a 3 year- old boy affected by classic PKU and FD, both confirmed by molecular data. The FD was suspected at the age of 21 months on the presence of non-specific GI symptoms (severe abdominal pain and periodically appearance of not specific episodes of gastroenteritis apparently non related to PKU. Conclusion This is the first report of co-existence of FD and PKU, two different congenital inborn of metabolism and in consideration of the prevalence of each disease this chance association is a very unusual event. The co-existence of this diseases made very difficult the correct interpretation of clinical symptoms as lack of appetite, severe abdominal pain and non-specific gastroenteritis episodes. Furthermore, this case report helps to define the early clinical phenotype of FD.

  3. Co-existence of Methanogenesis and Sulfate Reduction with Common Substrates in Sulfate-Rich Estuarine Sediments

    Directory of Open Access Journals (Sweden)

    Michal Sela-Adler

    2017-05-01

    Full Text Available The competition between sulfate reducing bacteria and methanogens over common substrates has been proposed as a critical control for methane production. In this study, we examined the co-existence of methanogenesis and sulfate reduction with shared substrates over a large range of sulfate concentrations and rates of sulfate reduction in estuarine systems, where these processes are the key terminal sink for organic carbon. Incubation experiments were carried out with sediment samples from the sulfate-methane transition zone of the Yarqon (Israel estuary with different substrates and inhibitors along a sulfate concentrations gradient from 1 to 10 mM. The results show that methanogenesis and sulfate reduction can co-exist while the microbes share substrates over the tested range of sulfate concentrations and at sulfate reduction rates up to 680 μmol L-1 day-1. Rates of methanogenesis were two orders of magnitude lower than rates of sulfate reduction in incubations with acetate and lactate, suggesting a higher affinity of sulfate reducing bacteria for the available substrates. The co-existence of both processes was also confirmed by the isotopic signatures of δ34S in the residual sulfate and that of δ13C of methane and dissolved inorganic carbon. Copy numbers of dsrA and mcrA genes supported the dominance of sulfate reduction over methanogenesis, while showing also the ability of methanogens to grow under high sulfate concentration and in the presence of active sulfate reduction.

  4. Hydrothermal synthesis of Yttrium Orthovanadate (YVO4) and its application in photo catalytic degradation of sewage water

    International Nuclear Information System (INIS)

    Komal, J. K.; Karimi, P.; Hui, K. S.

    2010-01-01

    In this paper; YVO 4 powder was successfully synthesized from Vanadium Pentaoxide (V 2 O 5 ), Yttrium Oxide (Y 2 O 3 ) and ethyl acetate as a mineralizer by hydrothermal method at a low temperature (T=.230 d egree C , and P=100 bars). The as-prepared powders were characterized by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, UV-V Spectroscopy and Chemical Oxygen Demand of the sewage water, respectively. The results show that hydrothermal method can greatly promote the crystallization and growth of YVO 4 phase. X-ray Diffraction pattern clearly indicates the tetragonal structure and crystallinity. An fourier transform infrared spectrum of the YVO 4 shows the presence of Y-O and V-O bond, respectively. The presence of these two peaks indicates that yttrium vanadate has been formed. UV-V is absorption spectra suggesting that YVO 4 particles have stronger UV absorption than natural sunlight and subsequent photo catalytic degradation data also confirmed their higher photo catalytic activity.

  5. Synthesis, Characterization, and Photoelectrochemical Catalytic Studies of a Water-Stable Zinc-Based Metal-Organic Framework.

    Science.gov (United States)

    Altaf, Muhammad; Sohail, Manzar; Mansha, Muhammad; Iqbal, Naseer; Sher, Muhammad; Fazal, Atif; Ullah, Nisar; Isab, Anvarhusein A

    2018-02-09

    Metal-organic frameworks (MOFs) are class of porous materials that can be assembled in a modular manner by using different metal ions and organic linkers. Owing to their tunable structural properties, these materials are found to be useful for gas storage and separation technologies, as well as for catalytic applications. A cost-effective zinc-based MOF ([Zn(bpcda)(bdc)] n ) is prepared by using N,N'-bis(pyridin-4-ylmethylene)cyclohexane-1,4-diamine [N,N'-bis(pyridin-4-ylmethylene)cyclohexane-1,4-diamine] and benzenedicarboxylic acid (bdc) linkers. This new material exhibits remarkable photoelectrochemical (PEC) catalytic activity in water splitting for the evolution of oxygen. Notably, this non-noble metal-based MOF, without requiring immobilization on other supports or containing metal particles, produced a highest photocurrent density of 31 μA cm -2 at 0.9 V, with appreciable stability and negligible photocorrosion. Advantageously for the oxygen evolution process, no external reagents or sacrificial agents are required in the aqueous electrolyte solution. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation. 1998 annual progress report

    International Nuclear Information System (INIS)

    Sen, A.

    1998-01-01

    'Toxic organics and polymers pose a serious threat to the environment, especially when they are present in aquatic systems. The objective of the research is the design of practical procedures for the removal and/or recycling of such pollutants by oxidation. This report summarizes the work performed in the first one and half years of a three year project. The authors had earlier described a catalytic system for the deep oxidation of toxic organics, such as benzene, phenol and substituted phenols, aliphatic and aromatic halogenated compounds, organophosphorus, and organosulfur compounds [1]. In this system, metallic palladium was found to catalyze the oxidation of the substrate by dioxygen in aqueous medium at 80--100 C in the presence of carbon monoxide. For all the substrates examined, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 h period. Because of a pressing need for new procedures for the destruction of chemical warfare agents, the authors have examined in detail the deep oxidation of appropriate model compounds containing phosphorus-carbon and sulfur-carbon bonds using the same catalytic system. The result is the first observation of the efficient catalytic oxidative cleavage of phosphorus-carbon and sulfur-carbon bonds under mild conditions, using dioxygen as the oxidant [2]. In addition to the achievements described above, they have unpublished results in several other areas. For example, they have investigated the possibility of using dihydrogen rather than carbon monoxide as a coreductant in the catalytic deep oxidation of substrates. Even more attractive from a practical standpoint is the possibility of using a mixture of carbon monoxide and dihydrogen (synthesis gas). Indeed, experiments indicated that it is possible to substitute carbon monoxide by dihydrogen or synthesis gas. Significantly, in the case of nitro compounds, the deep oxidation in fact proceeded

  7. Water oxidation catalyzed by mononuclear ruthenium complexes with a 2,2'-bipyridine-6,6'-dicarboxylate (bda) ligand: how ligand environment influences the catalytic behavior.

    Science.gov (United States)

    Staehle, Robert; Tong, Lianpeng; Wang, Lei; Duan, Lele; Fischer, Andreas; Ahlquist, Mårten S G; Sun, Licheng; Rau, Sven

    2014-02-03

    A new water oxidation catalyst [Ru(III)(bda)(mmi)(OH2)](CF3SO3) (2, H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; mmi = 1,3-dimethylimidazolium-2-ylidene) containing an axial N-heterocyclic carbene ligand and one aqua ligand was synthesized and fully characterized. The kinetics of catalytic water oxidation by 2 were measured using stopped-flow technique, and key intermediates in the catalytic cycle were probed by density functional theory calculations. While analogous Ru-bda water oxidation catalysts [Ru(bda)L2] (L = pyridyl ligands) are supposed to catalyze water oxidation through a bimolecular coupling pathway, our study points out that 2, surprisingly, undergoes a single-site water nucleophilic attack (acid-base) pathway. The diversion of catalytic mechanisms is mainly ascribed to the different ligand environments, from nonaqua ligands to an aqua ligand. Findings in this work provide some critical proof for our previous hypothesis about how alternation of ancillary ligands of water oxidation catalysts influences their catalytic efficiency.

  8. Conserved water-mediated H-bonding dynamics of catalytic Asn ...

    Indian Academy of Sciences (India)

    Prakash

    Extensive energy minimization and molecular dynamics simulation studies up to 2 ns ... Conserved water in molecular recognition; MD simulation; plant cysteine protease ..... Mustata G and Briggs J M 2004 Cluster analysis of water molecules.

  9. Burrow characteristics of the co-existing sibling species Mus booduga and Mus terricolor and the genetic basis of adaptation to hypoxic/hypercapnic stress

    Directory of Open Access Journals (Sweden)

    Narayan Gopeshwar

    2009-04-01

    Full Text Available Abstract Background The co-existing, sibling species Mus booduga and Mus terricolor show a difference in site-preference for burrows. The former build them in flat portion of the fields while the latter make burrows in earthen mounds raised for holding water in cultivated fields. In northern India which experiences great variation in climatic condition between summer and winter, M. booduga burrows have an average depth of 41 cm, as against 30 cm in southern India with less climatic fluctuation. M. terricolor burrows are about 20 cm deep everywhere. The three chromosomal species M. terricolor I, II and III have identical burrows, including location of the nest which is situated at the highest position. In contrast, in M. booduga burrows, the nest is at the lowest position. Results The nest chamber of M. booduga is located at greater depth than the nest chamber of M. terricolor. Also, in the burrows of M. booduga the exchange of air takes place only from one side (top surface in contrast to the burrows of M. terricolor where air exchange is through three sides. Hence, M. booduga lives in relatively more hypoxic and hypercapnic conditions than M. terricolor. We observed the fixation of alternative alleles in M. booduga and M. terricolor at Superoxide dismutase-1 (Sod-1, Transferrin (Trf and Hemoglobin beta chain (Hbb loci. All the three are directly or indirectly dependent on oxygen concentration for function. In addition to these, there are differences in burrow patterns and site-preference for burrows suggesting difference in probable adaptive strategy in these co-existing sibling species. Conclusion The burrow structure and depth of nest of the chromosomal species M. terricolor I, II and III are same everywhere probably due to the recency of their evolutionary divergence. Moreover, there is lack of competition for the well-adapted 'microhabitats' since they are non-overlapping in distribution. However, the co-existing sibling species M. booduga

  10. 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.

  11. Infiltrating Ductal Carcinoma Co-Existing with Intraductal Papillary Carcinoma of Male Breast: A Rare Case Report.

    Science.gov (United States)

    Kumar, Mayank; Pottipati, Bhaswanth; Arakeri, Surekha U; Javalgi, Anita P

    2017-06-01

    Male breast carcinomas are rare tumours, accounting for less than 1% of all malignancies in men. Intracystic Papillary Carcinoma (IPC) in males is a very rare entity, representing 5-7.5% of all male breast carcinomas. It lacks the classical clinical, radiological and cytological features of malignancy and usually presents as a benign-appearing lump. We report a case of Infiltrating Ductal Carcinoma (IDC) co-existing with intracystic papillary carcinoma in a 53-year-old male who presented with lump in the right breast.

  12. The effects of aerobic exercise for persons with migraine and co-existing tension-type headache and neck pain. A randomized, controlled, clinical trial

    DEFF Research Database (Denmark)

    Krøll, Lotte Skytte; Hammarlund, Catharina Sjödahl; Linde, Mattias

    2018-01-01

    Aim To evaluate aerobic exercise in migraine and co-existing tension-type headache and neck pain. Methods Consecutively recruited persons with migraine and co-existing tension-type headache and neck pain were randomized into an exercise group or control group. Aerobic exercise consisted of bike...

  13. Catalytic oxidation of sulfide in drinking water treatment: activated carbon as catalyst; Katalytische Oxidation von Sulfid bei der Trinkwasseraufbereitung: Aktivkohle als Katalysator

    Energy Technology Data Exchange (ETDEWEB)

    Hultsch, V; Grischek, T; Wolff, D; Worch, E [Technische Univ. Dresden (Germany). Inst. fuer Wasserchemie; Gun, J [Hebrew Univ. of Jerusalem (Israel). Div. of Environmental Sciences, Fredy and Nadine Herrmann School of Applied Science

    2001-07-01

    In regions with warm climate and limited water resources high sulfide concentrations in groundwater can cause problems during drinking water treatment. Aeration of the raw water is not always sufficient to ensure the hydrogen sulfide concentration below the odour threshold value for hydrogen sulfide. As an alternative, activated carbon can be used as a catalyst for sulfide oxidation of raw water. The use of different types of activated carbon was investigated in kinetic experiments. Both Catalytic Carbon from Calgon Carbon and granulated activated carbon from Norit showed high catalytic activities. The results of the experiments are discussed with regard to the practical use of activated carbon for the elimination of hydrogen sulfide during drinking water treatment. (orig.)

  14. Co-existence of Distinct Prion Types Enables Conformational Evolution of Human PrPSc by Competitive Selection*

    Science.gov (United States)

    Haldiman, Tracy; Kim, Chae; Cohen, Yvonne; Chen, Wei; Blevins, Janis; Qing, Liuting; Cohen, Mark L.; Langeveld, Jan; Telling, Glenn C.; Kong, Qingzhong; Safar, Jiri G.

    2013-01-01

    The unique phenotypic characteristics of mammalian prions are thought to be encoded in the conformation of pathogenic prion proteins (PrPSc). The molecular mechanism responsible for the adaptation, mutation, and evolution of prions observed in cloned cells and upon crossing the species barrier remains unsolved. Using biophysical techniques and conformation-dependent immunoassays in tandem, we isolated two distinct populations of PrPSc particles with different conformational stabilities and aggregate sizes, which frequently co-exist in the most common human prion disease, sporadic Creutzfeldt-Jakob disease. The protein misfolding cyclic amplification replicates each of the PrPSc particle types independently and leads to the competitive selection of those with lower initial conformational stability. In serial propagation with a nonglycosylated mutant PrPC substrate, the dominant PrPSc conformers are subject to further evolution by natural selection of the subpopulation with the highest replication rate due to its lowest stability. Cumulatively, the data show that sporadic Creutzfeldt-Jakob disease PrPSc is not a single conformational entity but a dynamic collection of two distinct populations of particles. This implies the co-existence of different prions, whose adaptation and evolution are governed by the selection of progressively less stable, faster replicating PrPSc conformers. PMID:23974118

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

    Directory of Open Access Journals (Sweden)

    Renato Contreras

    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.

  16. 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; Li, Weiwei; Croue, Jean-Philippe

    2012-01-01

    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

  17. Corrigendum to Photo catalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-Zn O and Nano clay Composite

    International Nuclear Information System (INIS)

    Bak, S. A.; Song, M. S.; Nam, I.T.; Lee, W.G.

    2015-01-01

    In the published paper entitled Photo catalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-Zn O and Nano clay Composite [1], we mistakenly used Laponite in our paper. The corrected name is Laponite (BYK Corporations products). So we are making some changes from Laponite to Laponite (BYK Corporations products) in our paper.

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

    KAUST Repository

    Shinagawa, Tatsuya; Takanabe, Kazuhiro

    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

  19. 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.

  20. Role of Defects and Adsorbed Water Film in Influencing the Electrical, Optical and Catalytic Properties of Transition Metal Oxides

    Science.gov (United States)

    Wang, Qi

    , gallium nitride and zinc oxide. Most TMOs at room temperature are known to be strongly hydrated. We show that an adsorbed water film present on the surface of TMOs facilitates the dissolution of gaseous species and promotes charge transfers at the adsorbed-water/oxide interfaces. Further, we show the role of vacancy defects in enhancing catalytic processes by directly monitoring the charge transfer process between gaseous species and vacancy defects in non-stoichiometric p-type nickel oxide and n-type tungsten oxide using in-situ NIR-PL, electrical resistance, and X-ray photoelectron spectroscopy. We find the importance of adsorbed water and vacancy defects in affecting catalytic, electronic, electrical, and optical changes such as insulator-to-metal transitions and radiative emissions during electrochemical reactions. In addition, we demonstrate that electrochemical surface transfer doping exists in another system, specifically, in gallium nitride, and the presence of this adsorbed water film present on the surface of GaN induces electron transfer from GaN that leads to the formation of an electron depletion region on the surface.

  1. Effect of co-existing copper and calcium on the removal of As(V) by reused aluminum oxides.

    Science.gov (United States)

    Yang, J K; Park, Y J; Kim, K H; Lee, H Y; Min, K C; Lee, S M

    2013-01-01

    Among the various heavy metals, arsenic is frequently found in abandoned mine drainage and the environmental fate of arsenic in real aqueous solutions can be highly dependent on the presence of co-existing ions. In this study, removal of arsenate through adsorption on the reused aluminum oxide or through precipitation was investigated in a single and in a binary system as a function of pH and concentration. Different removal behaviors of arsenate were observed in the presence of different cations as well as a variation of the molar ratios of arsenate to cations. Co-operative effects on arsenate removal by precipitation in solution occurred with an increase of copper concentration, while a decrease of arsenate removal resulted in increasing calcium concentration. It was observed that the arsenate removal in the presence of calcium would be highly dependent on the molar ratios of both elements.

  2. The co-existence of a myxoid liposarcoma and leiomyoma in the same ovarian mass of a dog.

    Science.gov (United States)

    Shiwa, Nozomi; Boonsriroj, Hassadin; Kimitsuki, Kazunori; Shimatsu, Taichi; Park, Chun-Ho

    2016-03-01

    A 15-year-old, female mixed-breed dog presented with abdominal distention. An exploratory laparotomy revealed a large left ovarian mass (20 × 15 × 12 cm). Histopathological examination of the mass revealed a mixed myxoid liposarcoma and a well-differentiated leiomyoma. Four months after surgical removal of the mass, the dog died due to multiorgan metastasis. The metastasis was composed solely of the liposarcoma component. The liposarcoma component was Alcian Blue- and Oil red O-positive, and demonstrated immunoreactivity with S-100, adipophilin and vimentin. Electron microscopy revealed that the tumor cell cytoplasms were packed with lipid vacuoles and dilated rough endoplasmic reticulum. To our knowledge, this is the first report of myxoid liposarcoma and leiomyoma co-existing in a canine ovary.

  3. Interworking between IP security and NAT-PT under IPv4/IPv6 co-existent environments

    Science.gov (United States)

    Ye, Run-Guo; Yu, Shu-Yao; Yang, Hong-Wei; Song, Chuck

    2005-02-01

    Similar to conventional NAT gateways, NAT-PT gateways break traditional TCP/IP"s end-to-end argument property; hence, any IP-based applications protected by IPSec protocol cannot traverse NAT-PT gateways properly. The interworking issues between IPSec and NAT-PT gateways under IPv4/IPv6 co-existent environments were studied: this paper first pointed out the deficiency of current NAT-Traversal scheme when interworking with NAT-PT gateways and proposed an enhanced scheme, which enabled interworking between IPSec and NAT-PT gateways and served the following three scenarios: 1) secure communication between IPv6 hosts and IPv4 hosts; 2) secure communication between IPv6 subnets and IPv4 subnets; 3) secure communication between remote IPv6 hosts and legacy IPv4 subnets.

  4. A case of seropositive Neuromyelitis Optica in a paediatric patient with co-existing acute nephrotic syndrome.

    Science.gov (United States)

    Volkman, Thomas; Hemingway, Cheryl

    2017-11-01

    Neuromyelitis optica (NMO) and NMO spectrum disorder (NMOSD) is a rare relapsing autoimmune disease of the central nervous system constituting less than 1% of demyelinating diseases (Jeffery and Buncic, 1996). It preferentially affects the optic nerves and spinal cord, with the brain parenchyma generally spared. Demyelinating lesions are characterised by longitudinally extensive transverse myelitis (LETM) and often longitudinally extensive optic neuritis. Following the discovery of a novel pathogenic antibody, Aquaporin 4 in 2004 (Lennon et al., 2004) this disease has been seen as a separate entity from Multiple Sclerosis (MS). We report the case of a severe AQP4 IgG case of NMO in a 10 year old child. This case unusually had a coexisting diagnosis of acute nephrotic syndrome which has only been reported once previously in the literature 2 . This article will examine some of the treatment challenges and the spectrum of co-existing autoimmune disease in NMOSD. Copyright © 2017. Published by Elsevier B.V.

  5. Direct catalytic conversion of brown seaweed-derived alginic acid to furfural using 12-tungstophosphoric acid catalyst in tetrahydrofuran/water co-solvent

    International Nuclear Information System (INIS)

    Park, Geonu; Jeon, Wonjin; Ban, Chunghyeon; Woo, Hee Chul; Kim, Do Heui

    2016-01-01

    Highlights: • Furfural was produced by catalytic conversion of macroalgae-derived alginic acid. • 12-Tungstophosphoric acid (H_3PW_1_2O_4_0) showed remarkable catalytic performance. • Tetrahydrofuran (THF) as a reaction medium significantly enhanced production of furfural. - Abstract: Furfural, a biomass-derived platform chemical, was produced by acid-catalyzed reaction of alginic acid extracted from brown seaweed. Three acid catalysts, H_2SO_4, Amberlyst15 and 12-tungstophosphoric acid (H_3PW_1_2O_4_0), were compared to evaluate their catalytic performance for the alginic acid conversion. The H_3PW_1_2O_4_0 catalyst showed the highest catalytic activity, yielding the maximum furfural yield (33.8%) at 180 °C for 30 min in tetrahydrofuran/water co-solvent. Higher reaction temperature promoted the conversion of alginic acid to furfural, but the transformation of furfural to humin was also accelerated. To our knowledge, this is the highest furfural yield among studies about the direct catalytic conversion of alginic acid. Furthermore, products distribution with time-on-stream was investigated in detail, which led us to propose a reaction pathway.

  6. 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.

  7. An animal model of co-existing sarcopenia and osteoporotic fracture in senescence accelerated mouse prone 8 (SAMP8).

    Science.gov (United States)

    Zhang, Ning; Chow, Simon Kwoon Ho; Leung, Kwok Sui; Lee, Ho Hin; Cheung, Wing Hoi

    2017-10-15

    Sarcopenia and osteoporotic fracture are common aging-related musculoskeletal problems. Recent evidences report that osteoporotic fracture patients showed high prevalence of sarcopenia; however, current clinical practice basically does not consider sarcopenia in the treatment or rehabilitation of osteoporotic fracture. There is almost no report studying the relationship of the co-existing of sarcopenia and osteoporotic fracture healing. In this study, we validated aged senescence accelerated mouse prone 8 (SAMP8) and senescence accelerated mouse resistant 1 (SAMR1) as animal models of senile osteoporosis with/without sarcopenia. Bone mineral density (BMD) at the 5th lumbar and muscle testing of the two animal strains were measured to confirm the status of osteoporosis and sarcopenia, respectively. Closed fracture was created on the right femur of 8-month-old animals. Radiographs were taken weekly post-fracture. MicroCT and histology of the fractured femur were performed at week 2, 4 and 6 post-fracture, while mechanical test of both femora at week 4 and 6 post-fracture. Results showed that the callus of SAMR1 was significantly larger at week 2 but smaller at week 6 post-fracture than SAMP8. Mechanical properties were significantly better at week 4 post-fracture in SAMR1 than SAMP8, indicating osteoporotic fracture healing was delayed in sarcopenic SAMP8. This study validated an animal model of co-existing sarcopenia and osteoporotic fracture, where a delayed fracture healing might be resulted in the presence of sarcopenia. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Catalytic hydrolysis of Metil Teret Botil Eter in under ground contaminated water

    International Nuclear Information System (INIS)

    Nikpey, A.; Mortazavi, B.; Asilian, H.; Khavanin, A.; Rezaee, A.; Soleimanian, A.; Kazemian, H.

    2005-01-01

    The behavior of ZSM-5 and Mordenite catalyst in the hydrolysis at room temperature of methyl tert-butyl ether was studied with reference to the possibility of its conversion to more biodegradable products in underground water contaminated by methyl tert-butyl ether. Hydrolysis products were determined using a gas chromatograph equipped with a flame ionization detector. The results indicate that acid ZSM-5 catalyst are effective in both adsorption and hydrolysis of methyl tert-butyl ether and may be applied for both in situ underground water remediation and as protection barrier for wells or leaking tanks. However, acid mordenite catalyst completely inactive

  9. Surface water retardation around single-chain polymeric nanoparticles: critical for catalytic function?

    Science.gov (United States)

    Stals, Patrick J M; Cheng, Chi-Yuan; van Beek, Lotte; Wauters, Annelies C; Palmans, Anja R A; Han, Songi; Meijer, E W

    2016-03-01

    A library of water-soluble dynamic single-chain polymeric nanoparticles (SCPN) was prepared using a controlled radical polymerisation technique followed by the introduction of functional groups, including probes at targeted positions. The combined tools of electron paramagnetic resonance (EPR) and Overhauser dynamic nuclear polarization (ODNP) reveal that these SCPNs have structural and surface hydration properties resembling that of enzymes.

  10. 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

  11. Effects of complexation of oppositely charged water-soluble cobaltphthalocyanines on catalytic mercaptoethanol autoxidation

    NARCIS (Netherlands)

    Schipper, E.T.W.M.; Heuts, J.P.A.; Piet, P.; Beelen, T.P.M.; German, A.L.

    1994-01-01

    In order to elucidate the different promoting effects polycations have on cobalt(II) phthalocyanine-catalyzed autoxidn. of 2-mercaptoethanol, the properties of mixts. of oppositely charged water-sol. cobalt(II) phthalocyanines were studied. The contribution of polycation-induced dimerization of the

  12. 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

  13. Catalytic Water Oxidation by a Bio-inspired Nickel Complex with Redox Active Ligand

    Science.gov (United States)

    Wang, Dong; Bruner, Charlie O.

    2017-01-01

    The oxidation of water to dioxygen is important in natural photosynthesis. One of nature’s strategies for managing such multi-electron transfer reactions is to employ redox active metal-organic cofactor arrays. One prototype example is the copper-tyrosinate active site found in galactose oxidase. In this work, we have implemented such a strategy to develop a bio-inspired nickel-phenolate complex capable of catalyzing the oxidation of water to O2 electrochemically at neutral pH with a modest overpotential. The employment of the redox-active ligand turned out to be a useful strategy to avoid the formation of high-valent nickel intermediates while a reasonable turnover rate (0.15 s−1) is retained. PMID:29099176

  14. The influence of water vapor and sulfur dioxide on the catalytic decomposition of nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yalamas, C.; Heinisch, R.; Barz, M. [Technische Univ. Berlin (Germany). Inst. fuer Energietechnik; Cournil, M. [Ecole Nationale Superieure des Mines, 42 - Saint-Etienne (France)

    2001-03-01

    For the nitrous oxide decomposition three groups of catalysts such as metals on support, hydrotalcites, and perovskites were studied relating to their activity in the presence of vapor or sulfur dioxide, in the temperature range from 200 to 500 C. It was found that the water vapor strongly inhibates the nitrous oxide decomposition at T=200-400 C. The sulfur dioxide poisons the catalysts, in particular the perovskites. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Jakob G. Howalt

    2014-01-01

    Full Text Available 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 functional theory calculations are used in combination with the computational hydrogen electrode approach to calculate the free energy profile for electrochemical protonation of O and N2 species on cuboctahedral Mo13 nanoclusters. The calculations show that the molybdenum nanocluster will preferentially bind oxygen over nitrogen and hydrogen at neutral bias, but under electrochemical reaction conditions needed for nitrogen reduction, oxygen adsorption is severely weakened and the adsorption energy is comparable to hydrogen and nitrogen adsorption. The potentials required to reduce oxygen off the surface are −0.72 V or lower for all oxygen coverages studied, and it is thus possible to (reactivate (partially oxidized nanoclusters for electrochemical ammonia production, e.g., using a dry proton conductor or an aqueous electrolyte. At lower oxygen coverages, nitrogen molecules can adsorb to the surface and electrochemical ammonia production via the associative mechanism is possible at potentials as low as −0.45 V to −0.7 V.

  16. A Self-Assembled Trigonal Prismatic Molecular Vessel for Catalytic Dehydration Reactions in Water.

    Science.gov (United States)

    Das, Paramita; Kumar, Atul; Howlader, Prodip; Mukherjee, Partha Sarathi

    2017-09-12

    A water-soluble Pd 6 trigonal prism (A) was synthesized by two-component coordination-driven self-assembly of a Pd II 90° acceptor with a tetraimidazole donor. The walls of the prism are constructed by three conjugated aromatic building blocks, which means that the confined pocket of the prism is hydrophobic. In addition to the hydrophobic cavity, large product egress windows make A an ideal molecular vessel to catalyze otherwise challenging pseudo-multicomponent dehydration reactions in its confined nanospace in aqueous medium. This study is an attempt at selective generation of the intermediate tetraketones and xanthenes by fine-tuning the reaction conditions employing a supramolecular molecular vessel. Moreover, either poor or no yield of the dehydrated products in the absence of A under similar reaction conditions supports the ability of the confined space of the barrel to promote such reactions in water. Furthermore, we focused on the rigidification of the tetraphenylethylene-based tetraimidazole unit anchored within the Pd II coordination architecture; enabling counter-anion dependent aggregation induced emission in the presence of water. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Catalytic subcritical water liquefaction of flax straw for high yield of furfural

    International Nuclear Information System (INIS)

    Harry, Inibehe; Ibrahim, Hussameldin; Thring, Ron; Idem, Raphael

    2014-01-01

    There is substantial interest in the application of biomass as a renewable fuel or for production of chemicals. Flax straw can be converted into valuable chemicals and biofuels via liquefaction in sub-critical water. In this study, the yield of furfural and the kinetics of flax straw liquefaction under sub-critical water conditions were investigated using a high-pressure autoclave reactor. The liquefaction was conducted in the temperature range of 175–325 °C, pressure of 0.1 MPa–8 MPa, retention time in the range of 0 min–120 min, and flax straw mass fraction (w F ) of 5–20 %. Also, the effect of acid catalysts on furfural yield was studied. The kinetic parameters of flax straw liquefaction were determined using nonlinear regression of the experimental data, assuming second-order kinetics. The apparent activation energy was found to be 27.97 kJ mol −1 while the reaction order was 2.0. The optimum condition for furfural yield was at 250 °C, 6.0 MPa, w F of 5% and 0 retention time after reaching set conditions. An acid catalyst was found to selectively favour furfural yield with 40% flax straw conversion. - Highlights: • Flax straw liquefaction in subcritical water. • Creation of a reaction pathway that can be used to optimized furfural production. • Acid catalyst selectively favoured furfural yield with respect to other liquid products. • At the highest process temperature of 325 °C, a carbon conversion of 40% was achieved. • Activation energy and reaction order was 28 kJ/mol and 2.0 respectively

  18. Preparation of fluidized catalytic cracking slurry oil-in-water emulsion as anti-collapse agent for drilling fluids

    Directory of Open Access Journals (Sweden)

    Zhengqiang Xiong

    2016-12-01

    Full Text Available Fluidized catalytic cracking slurry oil-in-water emulsion (FCCSE was prepared by using interfacial complexes generation method that was simple and versatile. The critical factors influencing the sample preparation process were optimized, for instance, the optimum value of the mixed hydrophile-lipophile balance of compound emulsifier was 11.36, the content of compound emulsifier was 4 wt%, the emulsification temperature was 75 °C, the agitation speed was 200 rpm, and the emulsification time was 30–45 min. The performance as a drilling fluid additive was also investigated with respect to rheological properties, filtration loss and inhibition of FCCSE. Experimental results showed that FCCSE was favorable to inhibiting clay expansion and dispersion and reducing fluid loss. Furthermore, it had good compatibility with other additives and did not affect the rheological properties of drilling fluids. FCCSE exhibited better performance than the available emulsified asphalt. It has a promising application as anti-collapse agent in petroleum and natural gas drilling.

  19. Base-enhanced catalytic water oxidation by a carboxylate–bipyridine Ru(II) complex

    Energy Technology Data Exchange (ETDEWEB)

    Song, Na [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Brookhaven National Lab. (BNL), Upton, NY (United States); Concepcion, Javier J. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Binstead, Robert A. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Rudd, Jennifer A. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Vannucci, Aaron K. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemistry and Biochemistry; Dares, Christopher J. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Coggins, Michael K. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry; Meyer, Thomas J. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry

    2015-04-06

    In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [RuII(bda)(isoq)2] (bda is 2,2'-bipyridine-6,6'-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [RuII(CO2-bpy-CO2$-$)(isoq)2(NCCH3)], as shown by 1H and 13C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, as measured by cyclic voltammetry (CV). In 1.0 M PO43–, the calculated half-time for water oxidation is ~7 μs. In conclusion, the key to the rate accelerations with added bases is direct involvement of the buffer base in either atom–proton transfer (APT) or concerted electron–proton transfer (EPT) pathways.

  20. Proton transport facilitating water-oxidation: the role of second sphere ligands surrounding the catalytic metal cluster.

    Science.gov (United States)

    Bao, Han; Dilbeck, Preston L; Burnap, Robert L

    2013-10-01

    The ability of PSII to extract electrons from water, with molecular oxygen as a by-product, is a remarkable biochemical and evolutionary innovation. From an evolutionary perspective, the invention of PSII approximately 2.7 Ga led to the accelerated accumulation of biomass in the biosphere and the accumulation of oxygen in the atmosphere, a combination that allowed for the evolution of a much more complex and extensive biosphere than would otherwise have been possible. From the biochemical and enzymatic perspective, PSII is remarkable because of the thermodynamic and kinetic obstacles that needed to have been overcome to oxidize water as the ultimate photosynthetic electron donor. This article focuses on how proton release is an integral part of how these kinetic and thermodynamic obstacles have been overcome: the sequential removal of protons from the active site of H2O-oxidation facilitates the multistep oxidation of the substrate water at the Mn4CaOx, the catalytic heart of the H2O-oxidation reaction. As noted previously, the facilitated deprotonation of the Mn4CaOx cluster exerts a redox-leveling function preventing the accumulation of excess positive charge on the cluster, which might otherwise hinder the already energetically difficult oxidation of water. Using recent results, including the characteristics of site-directed mutants, the role of the second sphere of amino acid ligands and the associated network of water molecules surrounding the Mn4CaOx is discussed in relation to proton transport in other systems. In addition to the redox-leveling function, a trapping function is assigned to the proton release step occurring immediately prior to the dioxygen chemistry. This trapping appears to involve a yet-to-be clarified gating mechanism that facilitates to coordinated release of a proton from the neighborhood of the active site thereby insuring that the backward charge-recombination reaction does not out-compete the forward reaction of dioxygen chemistry

  1. 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.

  2. 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.

  3. 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

    are -0.72 V or lower for all oxygen coverages studied, and it is thus possible to (re)activate (partially) oxidized nanoclusters for electrochemical ammonia production, e.g., using a dry proton conductor or an aqueous electrolyte. At lower oxygen coverages, nitrogen molecules can adsorb to the surface...... and electrochemical ammonia production via the associative mechanism is possible at potentials as low as -0.45 V to -0.7 V. © 2014 Howalt and Vegge........ 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...

  4. Catalytic Water Oxidation by a Bio-inspired Nickel Complex with a Redox-Active Ligand.

    Science.gov (United States)

    Wang, Dong; Bruner, Charlie O

    2017-11-20

    The oxidation of water (H 2 O) to dioxygen (O 2 ) is important in natural photosynthesis. One of nature's strategies for managing such multi-electron transfer reactions is to employ redox-active metal-organic cofactor arrays. One prototype example is the copper tyrosinate active site found in galactose oxidase. In this work, we have implemented such a strategy to develop a bio-inspired nickel phenolate complex capable of catalyzing the oxidation of H 2 O to O 2 electrochemically at neutral pH with a modest overpotential. Employment of the redox-active ligand turned out to be a useful strategy to avoid the formation of high-valent nickel intermediates while a reasonable turnover rate (0.15 s -1 ) is retained.

  5. Removal of distal protein-water hydrogen bonds in a plant epoxide hydrolase increases catalytic turnover but decreases thermostability.

    Science.gov (United States)

    Thomaeus, Ann; Naworyta, Agata; Mowbray, Sherry L; Widersten, Mikael

    2008-07-01

    A putative proton wire in potato soluble epoxide hydrolase 1, StEH1, was identified and investigated by means of site-directed mutagenesis, steady-state kinetic measurements, temperature inactivation studies, and X-ray crystallography. The chain of hydrogen bonds includes five water molecules coordinated through backbone carbonyl oxygens of Pro(186), Leu(266), His(269), and the His(153) imidazole. The hydroxyl of Tyr(149) is also an integrated component of the chain, which leads to the hydroxyl of Tyr(154). Available data suggest that Tyr(154) functions as a final proton donor to the anionic alkylenzyme intermediate formed during catalysis. To investigate the role of the putative proton wire, mutants Y149F, H153F, and Y149F/H153F were constructed and purified. The structure of the Y149F mutant was solved by molecular replacement and refined to 2.0 A resolution. Comparison with the structure of wild-type StEH1 revealed only subtle structural differences. The hydroxyl group lost as a result of the mutation was replaced by a water molecule, thus maintaining a functioning hydrogen bond network in the proton wire. All mutants showed decreased catalytic efficiencies with the R,R-enantiomer of trans-stilbene oxide, whereas with the S,S-enantiomer, k (cat)/K (M) was similar or slightly increased compared with the wild-type reactions. k (cat) for the Y149F mutant with either TSO enantiomer was increased; thus the lowered enzyme efficiencies were due to increases in K (M). Thermal inactivation studies revealed that the mutated enzymes were more sensitive to elevated temperatures than the wild-type enzyme. Hence, structural alterations affecting the hydrogen bond chain caused increases in k (cat) but lowered thermostability.

  6. Co-existence of mucin-producing urothelial-type adenocarcinoma of the prostate and inverted papilloma of the bladder

    Directory of Open Access Journals (Sweden)

    Xiao-Nan Mu

    2017-06-01

    Full Text Available Adenocarcinoma of prostate with mucinous differentiation arising in the male urethra is extremely rare, with only 21 cases reported in the previous literature. A diagnosis of mucin-producing urothelial carcinoma of the prostate is based on the pathology, immunohistochemistry, and clinical examination by excluding the secondary adenocarcinoma of the prostate. We present a case of unexpected mucinous urothelial carcinoma of prostate with co-existing inverted papilloma of bladder in a 57-year-old man. The patient underwent transurethral resection of the prostate (TURP and transurethral resection of a bladder tumour (TUR-Bt, and the pathologic result showed mucinous prostate carcinoma and bladder inverted papilloma. Immunohistological stain was negative for prostate-specific antigen (PSA, prostate-specific acid phosphatase (PSAP, and P63, but positive for cytokeratin 7 (CK 7, CK 20, clone 34E12 and P504S. A complete endoscopic examination was performed to exclude the secondary adenocarcinoma of prostate. This case illustrates the clinical and pathological features of a rare and unexpected mucin-producing urothelial carcinoma of prostate in a bladder neoplasm patient.

  7. The co-existence of depression, anxiety and post-traumatic stress symptoms in the perinatal period: A systematic review.

    Science.gov (United States)

    Agius, Andee; Xuereb, Rita Borg; Carrick-Sen, Debbie; Sultana, Roberta; Rankin, Judith

    2016-05-01

    to identify and appraise the current international evidence regarding the presence and prevalence of the co-existence of depression, anxiety and post-traumatic stress symptoms in the antenatal and post partum period. using a list of keywords, Medline, CINHAL, Cochrane Library, EMBASE, PsychINFO, Web of Science and the Index of Theses and Conference Proceedings (Jan 1960 - Jan 2015) were systematically searched. Experts in the field were contacted to locate papers that were in progress or in press. Reference lists from relevant review articles were searched. Inclusion criteria included full papers published in English reporting concurrent depression, anxiety and post-traumatic stress symptoms in pregnant and post partum women. A validated data extraction review tool was used. 3424 citations were identified. Three studies met the full inclusion criteria. All reported findings in the postnatal period. No antenatal studies were identified. The prevalence of triple co-morbidity was relatively low ranging from 2% to 3%. triple co-morbidity does occur, although the prevalence appears to be low. Due to the presentation of complex symptoms, women with triple co-morbidity are likely to be difficult to identify, diagnose and treat. Clinical staff should be aware of the potential of complex symptomatology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Sorting out co-occurrence of rare monogenic retinopathies: Stargardt disease co-existing with congenital stationary night blindness.

    Science.gov (United States)

    Huynh, Nancy; Jeffrey, Brett G; Turriff, Amy; Sieving, Paul A; Cukras, Catherine A

    2014-03-01

    Inherited retinal diseases are uncommon, and the likelihood of having more than one hereditary disorder is rare. Here, we report a case of Stargardt disease and congenital stationary night blindness (CSNB) in the same patient, and the identification of two novel in-frame deletions in the GRM6 gene. The patient underwent an ophthalmic exam and visual function testing including: visual acuity, color vision, Goldmann visual field, and electroretinography (ERG). Imaging of the retina included fundus photography, spectral-domain optical coherence tomography (OCT), and fundus autofluorescence. Genomic DNA was PCR-amplified for analysis of all coding exons and flanking splice sites of both the ABCA4 and GRM6 genes. A 46-year-old woman presented with recently reduced central vision and clinical findings of characteristic yellow flecks consistent with Stargardt disease. However, ERG testing revealed an ERG phenotype unusual for Stargardt disease but consistent with CSNB1. Genetic testing revealed two previously reported mutations in the ABCA4 gene and two novel deletions in the GRM6 gene. Diagnosis of concurrent Stargardt disease and CSNB was made on the ophthalmic history, clinical examination, ERG, and genetic testing. This case highlights that clinical tests need to be taken in context, and that co-existing retinal dystrophies and degenerations should be considered when clinical impressions and objective data do not correlate.

  10. 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

    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...... around −2.5 eV. No clear correlation exists with the adsorption energy of CO. In contrast, the activity for the Ce0.75Zr0.25O2 support increases with increasing adsorption strength for CO, and based on a relatively low activity of Cu the activity does not seem to depend on the adsorption energy of oxygen...

  11. Catalytic activity of some oxime-based Pd(II-complexes in Suzuki coupling of aryl and heteroaryl bromides in water

    Directory of Open Access Journals (Sweden)

    Kamal M. Dawood

    2017-05-01

    Full Text Available The catalytic activity of four Pd(II-complexes of benzoazole-oximes was extensively studied in Suzuki–Miyaura C–C cross coupling reactions in water, as an eco-friendly green solvent, under both thermal heating as well as microwave irradiation conditions. The cross-coupling reactions included different activated and deactivated aryl- or heteroaryl-bromides with several arylboronic acids. The protected oxime-complexes were found to be more efficient than the free ones.

  12. Experimental model considerations for the study of protein-energy malnutrition co-existing with ischemic brain injury.

    Science.gov (United States)

    Prosser-Loose, Erin J; Smith, Shari E; Paterson, Phyllis G

    2011-05-01

    Protein-energy malnutrition (PEM) affects ~16% of patients at admission for stroke. We previously modeled this in a gerbil global cerebral ischemia model and found that PEM impairs functional outcome and influences mechanisms of ischemic brain injury and recovery. Since this model is no longer reliable, we investigated the utility of the rat 2-vessel occlusion (2-VO) with hypotension model of global ischemia for further study of this clinical problem. Male, Sprague-Dawley rats were exposed to either control diet (18% protein) or PEM induced by feeding a low protein diet (2% protein) for 7d prior to either global ischemia or sham surgery. PEM did not significantly alter the hippocampal CA1 neuron death (p = 0.195 by 2-factor ANOVA) or the increase in dendritic injury caused by exposure to global ischemia. Unexpectedly, however, a strong trend was evident for PEM to decrease the consistency of hippocampal damage, as shown by an increased incidence of unilateral or no hippocampal damage (p=0.069 by chi-square analysis). Although PEM caused significant changes to baseline arterial blood pH, pO(2), pCO(2), and fasting glucose (p0.269). Intra-ischemic tympanic temperature and blood pressure were strictly and equally controlled between ischemic groups. We conclude that co-existing PEM confounded the consistency of hippocampal injury in the 2-VO model. Although the mechanisms responsible were not identified, this model of brain ischemia should not be used for studying this co-morbidity factor. © 2011 Bentham Science Publishers Ltd.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 K 3 PO 4 , clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10 wt.% K 3 PO 4 + 10 wt.% clinoptilolite as catalysts to the soil at 2 wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10 wt.% 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 10 wt% clinoptilolite at 400 °C, and 30 wt% K 3 PO 4 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. - Highlights: • High quality biochar was made by catalytic pyrolysis in a microwave reactor. • High heating rate and good biochar quality were achieved using K 3 PO 4 and clinoptilolite mixture. • Biochars showed significant increase in soil WHC and CEC. • Microwave catalytic pyrolysis can produce

  14. 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 MPL exon-10 mutation should be pursued.

  15. Level of physical activity, well-being, stress and self-rated health in persons with migraine and co-existing tension-type headache and neck pain.

    Science.gov (United States)

    Krøll, Lotte Skytte; Hammarlund, Catharina Sjödahl; Westergaard, Maria Lurenda; Nielsen, Trine; Sloth, Louise Bönsdorff; Jensen, Rigmor Højland; Gard, Gunvor

    2017-12-01

    The prevalence of migraine with co-existing tension-type headache and neck pain is high in the general population. However, there is very little literature on the characteristics of these combined conditions. The aim of this study was to investigate a) the prevalence of migraine with co-existing tension-type headache and neck pain in a clinic-based sample, b) the level of physical activity, psychological well-being, perceived stress and self-rated health in persons with migraine and co-existing tension-type headache and neck pain compared to healthy controls, c) the perceived ability of persons with migraine and co-existing tension-type headache and neck pain to perform physical activity, and d) which among the three conditions (migraine, tension-type headache or neck pain) is rated as the most burdensome condition. The study was conducted at a tertiary referral specialised headache centre where questionnaires on physical activity, psychological well-being, perceived stress and self-rated health were completed by 148 persons with migraine and 100 healthy controls matched by sex and average age. Semi-structured interviews were conducted to assess characteristics of migraine, tension-type headache and neck pain. Out of 148 persons with migraine, 100 (67%) suffered from co-existing tension-type headache and neck pain. Only 11% suffered from migraine only. Persons with migraine and co-existing tension-type headache and neck pain had lower level of physical activity and psychological well-being, higher level of perceived stress and poorer self-rated health compared to healthy controls. They reported reduced ability to perform physical activity owing to migraine (high degree), tension-type headache (moderate degree) and neck pain (low degree). The most burdensome condition was migraine, followed by tension-type headache and neck pain. Migraine with co-existing tension-type headache and neck pain was highly prevalent in a clinic-based sample. Persons with migraine and co-existing

  16. Catalytic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bindley, W T.R.

    1931-04-18

    An apparatus is described for the catalytic treatment of liquids, semi-liquids, and gases comprising a vessel into which the liquid, semi-liquid, or gas to be treated is introduced through a common inlet to a chamber within the vessel whence it passes to contact with a catalyst through radially arranged channels or passages to a common outlet chamber.

  17. Effect of Combination Therapy with Atorvastatin and Ursodeoxycholic Acid on the Course of Ischemic Heart Disease with Co-Existent Non-Alcoholic Fatty Liver Disease and Obesity

    Directory of Open Access Journals (Sweden)

    Nataliya Karpyshyn

    2016-12-01

    Conclusions. The use of ursodeoxycholic acid in addition to atorvastatin in patients with ischemic heart disease, co-existent non-alcoholic fatty liver disease and obesity makes it possible to avoid the adverse effect of hypolipidemic therapy on the functional status of the liver.

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

    NARCIS (Netherlands)

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

  19. Direct and Interaction Effects of Co-Existing Familial Risk Factors and Protective Factors Associated with Internet Addiction among Chinese Students in Hong Kong

    Science.gov (United States)

    Wu, Anise M. S.; Lau, Joseph T. F.; Cheng, Kit-man; Law, Rita W.; Tse, Vincent W. S.; Lau, Mason M. C.

    2018-01-01

    Internet addiction (IA) is prevalent among adolescents and imposes a serious public health threat. Familial risk and protective factors may co-exist and interact with each other to determine IA. We conducted a cross-sectional survey among 9,618 Secondary 1 to 4 students in Hong Kong, China. About 16% of the surveyed students were classified as…

  20. Considerations for Managing Agricultural Co-Existence between Transgenic and Non-Transgenic Cultivars of Outcrossing Perennial Forage Plants in Dairy Pastures

    Directory of Open Access Journals (Sweden)

    Kevin F. Smith

    2016-11-01

    Full Text Available Many of the major forage species used in agriculture are outcrossing and rely on the exchange of pollen between individuals for reproduction; this includes the major species used for dairy production in grazing systems: perennial ryegrass (Lolium perenne L. and white clover (Trifolium repens L.. Cultivars of these species have been co-existing since contrasting cultivars were developed using plant breeding, but the consequences and need for strategies to manage co-existence have been made more prominent with the advent of genetic modification. Recent technological developments have seen the experimental evaluation of genetically modified (GM white clover and perennial ryegrass, although there is no current commercial growing of GM cultivars of these species. Co-existence frameworks already exist for two major cross-pollinated grain crops (canola and maize in Europe, and for alfalfa (Medicago sativa L. in the US, so many of the principles that the industry has developed for co-existence in these crops such as detection techniques, segregation, and agronomic management provide lessons and guidelines for outcrossing forage species, that are discussed in this paper.

  1. Dual Role of Water in Heterogeneous Catalytic Hydrolysis of Sarin by Zirconium-Based Metal-Organic Frameworks.

    Science.gov (United States)

    Momeni, Mohammad R; Cramer, Christopher J

    2018-05-22

    Recent experimental studies on Zr IV -based metal-organic frameworks (MOFs) have shown the extraordinary effectiveness of these porous materials for the detoxification of phosphorus-based chemical warfare agents (CWAs). However, pressing challenges remain with respect to characterizing these catalytic processes both at the molecular and crystalline levels. We here use theory to compare the reactivity of different zirconium-based MOFs for the catalytic hydrolysis of the CWA sarin, using both periodic and cluster modeling. We consider both hydrated and dehydrated secondary building units, as well as linker functionalized MOFs, to more fully understand and rationalize available experimental findings as well as to enable concrete predictions for achieving higher activities for the decomposition of CWAs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sung, K. W.; Na, J. W.; Cho, Y. H.; Kim, K. R

    1999-01-01

    In an experiment on TiO{sub 2} 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) = {delta} ({epsilon} - a ){sup 1/3} + b where, {epsilon} : atomic charge of nitrogen in a molecular, {delta}, a and b : corrective coefficients.

  3. I2-SDS-H2O System: A highly Efficient Dual Catalytic Green System for Deprotection of Imines and in Situ Preparation of Bis(indolyl)alkanes from Indoles in Water.

    Science.gov (United States)

    Hazarika, Parasa; Pahari, Pallab; Borah, Manash Jyoti; Konwar, Dilip

    2012-01-01

    A novel catalytic system consisting of I2-SDS-H2O has been developed which cleaves 2,3-diaza-1,3-butadiene, 1-aza-1,3-butadienes, oximes and in presence of indoles in the medium uses the corresponding aldehyde products to produce bis(indolyl)alkanes in situ. This one pot simple and mild dual catalytic system works in water at room temperature under neutral conditions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Badr A. [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Agricultural Engineering Department, Cairo University, Giza (Egypt); Ellis, Naoko [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Kim, Chang Soo [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Clean Energy Research Center, Korea Institute of Science and Technology, 14 gil 5 Hwarang-no Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Bi, Xiaotao, E-mail: tony.bi@ubc.ca [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Emam, Ahmed El-raie [Agricultural Engineering Department, Cairo University, Giza (Egypt)

    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 K{sub 3}PO{sub 4}, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10 wt.% K{sub 3}PO{sub 4} + 10 wt.% clinoptilolite as catalysts to the soil at 2 wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10 wt.% 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 10 wt% clinoptilolite at 400 °C, and 30 wt% K{sub 3}PO{sub 4} 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. - Highlights: • High quality biochar was made by catalytic pyrolysis in a microwave reactor. • High heating rate and good biochar quality were achieved using K{sub 3}PO{sub 4} and clinoptilolite mixture. • Biochars showed significant increase in soil WHC and CEC.

  5. A comparison study of the start-up of a MnOx filter for catalytic oxidative removal of ammonium from groundwater and surface water.

    Science.gov (United States)

    Cheng, Ya; Li, Ye; Huang, Tinglin; Sun, Yuankui; Shi, Xinxin; Shao, Yuezong

    2018-03-01

    As an efficient method for ammonium (NH 4 + ) removal, contact catalytic oxidation technology has drawn much attention recently, due to its good low temperature resistance and short start-up period. Two identical filters were employed to compare the process for ammonium removal during the start-up period for ammonium removal in groundwater (Filter-N) and surface water (Filter-S) treatment. Two types of source water (groundwater and surface water) were used as the feed waters for the filtration trials. Although the same initiating method was used, Filter-N exhibited much better ammonium removal performance than Filter-S. The differences in catalytic activity among these two filters were probed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and compositional analysis. XRD results indicated that different manganese oxide species were formed in Filter-N and Filter-S. Furthermore, the Mn3p XPS spectra taken on the surface of the filter films revealed that the average manganese valence of the inactive manganese oxide film collected from Filter-S (FS-MnO x ) was higher than in the film collected from Filter-N (FN-MnO x ). Mn(IV) was identified as the predominant oxidation state in FS-MnO x and Mn(III) was identified as the predominant oxidation state in FN-MnO x . The results of compositional analyses suggested that polyaluminum ferric chloride (PAFC) used during the surface water treatment was an important factor in the mineralogy and reactivity of MnO x . This study provides the theoretical basis for promoting the wide application of the technology and has great practical significance. Copyright © 2017. Published by Elsevier B.V.

  6. Study on treatment of distilled ammonia waste water from coke plant with activated carbon-NaClO catalytic oxidation method

    Energy Technology Data Exchange (ETDEWEB)

    Luo, D.; Yi, P.; Liu, J.; Chen, A. [Xiangtan Polytechnic University, Xiangtan (China). Dept. of Chemical Enginering

    2001-12-01

    Catalytic oxidation method for the treatment of distilled ammonia waste water from coke plant was investigated using activated carbon as catalyst and NaClO as oxidant. The influences of main factors, such as NaClO, activated carbon, pH and reactionary time were discussed. The results showed that under the conditions of 25{degree}C, NaClO/CODO=1.5, carbon/NaClO=0.6 and pH=3.0, the reaction completed within 120 minutes with 99.5% of phenol removal and 75.8% of COD removal when the distilled ammonia waste water from coke plant which containing phenol 510 mg/L and CODO 8420 mg/L was treated. 13 refs., 4 figs.

  7. 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

    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...... 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...... 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....

  8. Revisiting the co-existence of Attention-Deficit/Hyperactivity Disorder and Chronic Tic Disorder in childhood-The case of colour discrimination, sustained attention and interference control.

    Science.gov (United States)

    Uebel-von Sandersleben, Henrik; Albrecht, Björn; Rothenberger, Aribert; Fillmer-Heise, Anke; Roessner, Veit; Sergeant, Joseph; Tannock, Rosemary; Banaschewski, Tobias

    2017-01-01

    Attention Deficit / Hyperactivity Disorder (ADHD) and Chronic Tic Disorder (CTD) are two common and frequently co-existing disorders, probably following an additive model. But this is not yet clear for the basic sensory function of colour processing sensitive to dopaminergic functioning in the retina and higher cognitive functions like attention and interference control. The latter two reflect important aspects for psychoeducation and behavioural treatment approaches. Colour discrimination using the Farnsworth-Munsell 100-hue Test, sustained attention during the Frankfurt Attention Inventory (FAIR), and interference liability during Colour- and Counting-Stroop-Tests were assessed to further clarify the cognitive profile of the co-existence of ADHD and CTD. Altogether 69 children were classified into four groups: ADHD (N = 14), CTD (N = 20), ADHD+CTD (N = 20) and healthy Controls (N = 15) and compared in cognitive functioning in a 2×2-factorial statistical model. Difficulties with colour discrimination were associated with both ADHD and CTD factors following an additive model, but in ADHD these difficulties tended to be more pronounced on the blue-yellow axis. Attention problems were characteristic for ADHD but not CTD. Interference load was significant in both Colour- and Counting-Stroop-Tests and unrelated to colour discrimination. Compared to Controls, interference load in the Colour-Stroop was higher in pure ADHD and in pure CTD, but not in ADHD+CTD, following a sub-additive model. In contrast, interference load in the Counting-Stroop did not reveal ADHD or CTD effects. The co-existence of ADHD and CTD is characterized by additive as well as sub-additive performance impairments, suggesting that their co-existence may show simple additive characteristics of both disorders or a more complex interaction, depending on demand. The equivocal findings on interference control may indicate limited validity of the Stroop-Paradigm for clinical assessments.

  9. Revisiting the co-existence of Attention-Deficit/Hyperactivity Disorder and Chronic Tic Disorder in childhood—The case of colour discrimination, sustained attention and interference control

    Science.gov (United States)

    Rothenberger, Aribert; Fillmer-Heise, Anke; Roessner, Veit; Sergeant, Joseph; Tannock, Rosemary; Banaschewski, Tobias

    2017-01-01

    Objective Attention Deficit / Hyperactivity Disorder (ADHD) and Chronic Tic Disorder (CTD) are two common and frequently co-existing disorders, probably following an additive model. But this is not yet clear for the basic sensory function of colour processing sensitive to dopaminergic functioning in the retina and higher cognitive functions like attention and interference control. The latter two reflect important aspects for psychoeducation and behavioural treatment approaches. Methods Colour discrimination using the Farnsworth-Munsell 100-hue Test, sustained attention during the Frankfurt Attention Inventory (FAIR), and interference liability during Colour- and Counting-Stroop-Tests were assessed to further clarify the cognitive profile of the co-existence of ADHD and CTD. Altogether 69 children were classified into four groups: ADHD (N = 14), CTD (N = 20), ADHD+CTD (N = 20) and healthy Controls (N = 15) and compared in cognitive functioning in a 2×2-factorial statistical model. Results Difficulties with colour discrimination were associated with both ADHD and CTD factors following an additive model, but in ADHD these difficulties tended to be more pronounced on the blue-yellow axis. Attention problems were characteristic for ADHD but not CTD. Interference load was significant in both Colour- and Counting-Stroop-Tests and unrelated to colour discrimination. Compared to Controls, interference load in the Colour-Stroop was higher in pure ADHD and in pure CTD, but not in ADHD+CTD, following a sub-additive model. In contrast, interference load in the Counting-Stroop did not reveal ADHD or CTD effects. Conclusion The co-existence of ADHD and CTD is characterized by additive as well as sub-additive performance impairments, suggesting that their co-existence may show simple additive characteristics of both disorders or a more complex interaction, depending on demand. The equivocal findings on interference control may indicate limited validity of the Stroop-Paradigm for

  10. Co-existence of phenylketonuria either with maple syrup urine disease or Sandhoff disease in two patients from Iran: emphasizing the role of consanguinity.

    Science.gov (United States)

    Abiri, Maryam; Talebi, Saeed; Uitto, Jouni; Youssefian, Leila; Vahidnezhad, Hassan; Shirzad, Tina; Salehpour, Shadab; Zeinali, Sirous

    2016-10-01

    Most inborn errors of metabolism (IEMs) are inherited in an autosomal recessive manner. IEMs are one of the major concerns in Iran due to its extensive consanguineous marriages. Herein, we report two patients with two co-existent IEMs: a girl affected by classic phenylketonuria (PKU) and maple syrup urine disease (MSUD) and a male patient affected with Sandhoff disease and PKU, where Sandhoff disease was suspected due to the presence of a cherry-red spot in the eyes at 6 months which is unrelated to PKU. Sequencing of candidate genes in the first patient revealed one novel and three recurrent compound heterozygous mutations of p.Ser231Pro and p.Ala300Ser in the PAH gene and p.Glu330Lys and p.Arg170Cys mutations in the BCKDHB gene. Genetic testing results in the second patient showed previously reported homozygous mutations of p.Arg261Gln in the PAH and p.Arg533Cys mutation in the HEXB gene. Genetic testing confirmed the clinical diagnosis of both diseases in both patients. To the best of our knowledge; this is the first report of the co-existence of two distinct genetic disorders in two individuals from Iran. Co-existent different IEMs in patients complicated the clinical diagnosis and management of the diseases.

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

    International Nuclear Information System (INIS)

    Hu Sheng; Xiao Chengjian; Zhu Zuliang; Luo Shunzhong; Wang Heyi; Luo Yangming; Wang Changbin

    2007-01-01

    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)

  12. Co-existence of wind seas and swells along the west coast of India during non-monsoon season

    Digital Repository Service at National Institute of Oceanography (India)

    Rashmi, R.; Aboobacker, V.M.; Vethamony, P; John, M.P

    -dimensional significant wind sea heightH ∗S and peak wind sea period T ∗P have been calculated (Fig. 9). The best fit between log (H ∗Sws) and log (T ∗Pws) has been es- timated and resolved as follows: Fig. 7. (a), (b), (c), (d), (e) and (f) are wave energy spectrum, wave... of shallow water waves along Indian coast, J. Coastl. Res., 19, 1052–1065, 2003. Neetu, S., Shetye, S., and Chandramohan, P.: Impact of sea-breeze on wind seas off Goa, west coast of India, J. Earth Sys. Sci., 115, 229–234, 2006. Peterson, E. W. and Hennessey...

  13. Comparison of health-related quality of life among men with different co-existing severe mental disorders in treatment for substance use.

    Science.gov (United States)

    Adan, Ana; Marquez-Arrico, Julia E; Gilchrist, Gail

    2017-10-23

    Patient-perceived health-related quality of life has become an important outcome in health care as an indicator of treatment effectiveness and recovery for patients with substance use disorder. As no study has assessed health-related quality of life among male patients with substance use disorder and co-existing severe mental illness, we compared health-related quality of life among patients with substance use disorder and the following severe mental illness diagnosis in Barcelona, Spain: schizophrenia, bipolar disorder, major depressive disorder, and examined the associations with clinically related variables. Additionally, we compared results for health-related quality of life in patients with substance use disorder and severe mental illness, with Spanish population norms. We assessed 107 substance use disorder male patients using the 36-Item Short Form Health Survey comparing results across three groups with: comorbid schizophrenia (n = 37), comorbid bipolar disorder (n = 34), and comorbid major depressive disorder (n = 36). Multiple analyses of variance were performed to explore health-related quality of life by the type of co-existing SMI and linear regression analyses examined clinical correlates for the 36-Item Short Form Health Survey dimensions for each group. There were differences in Physical Functioning, Vitality and the Physical Composite Scale among groups. Poorer Physical Functioning was observed for patients with comorbid schizophrenia (80.13±3.27) and major depressive disorder (81.97±3.11) compared with comorbid bipolar disorder patients (94.26±1.93). Patients with substance use disorder and schizophrenia presented lower scores in Vitality (41.6±2.80) than those with co-existing bipolar disorder (55.68±3.66) and major depressive disorder (53.63±2.92). Finally, results in the Physical Composite Scale showed lower scores for patients with comorbid schizophrenia (51.06±1.41) and major depressive disorder (51.99±1.87) than for those with

  14. Photobiodegradation of chlorinated water pollutants by a combined TiO2-polyaniline-enzyme catalytic system

    Science.gov (United States)

    Campanella, Luigi; Crescentini, G.; Militerno, S.

    1995-10-01

    The removal of xenobiotic compounds, such as chlorophenols and pesticides, from municipal and industrial wastewaters is an important task because of the toxicity and the tendency to bioaccumulation of these compounds. Among the several methods proposed, photodegradation catalyzed by suspended inorganic semiconductors (i.e. TiO2) has lately received wide attention because this process is fast, leads to non-toxic final products and shows a high degradation efficiency. In this work, the results obtained in the photodegradation of monochlorophenols using a new catalyst, made of TiO2 and polyaniline both immobilized on a polyvinylchloride (PVC) membrane, in presence (and in absence) of an enzyme are presented. Different enzymes have been tested by adding 5, 10 or 15 U/mL to 50 mL of aqueous solution (1 multiplied by 10-4 mol/L) of o-chloro-phenol containing the catalytic membrane. The samples were irradiated using a QUV panel accelerated weathering tester, which simulates very well the solar radiation up to lambda equals 400 nm and HPLC was used to measure the variation of the compound's concentration with the time. While some enzymes (i.e., peroxidase) do not improve the photodegradation process since they do not survive under the irradiation conditions used, some of them show marked effect both in terms of rate degradation and time required to reach the total degradation of the compound examined. For example, the addition of Laccase reduces the 100% degradation time from 35 hrs to about 20 hrs. Attempts to immobilize the enzyme on the catalytic membrane (by adsorption) have been carried out and the performance of the catalyst with non-immobilized and immobilized enzyme has been studied.

  15. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water

    International Nuclear Information System (INIS)

    Ma, Wei; Zong, Panpan; Cheng, Zihong; Wang, Baodong; Sun, Qi

    2014-01-01

    Highlights: • Biomass and fly ash which were widespread for adsorption of heavy metal ions. • Preparation of catalyst by saturated adsorbents for 2-chlorophenol ozone degradation. • This work demonstrated that the O 3 /catalyst process was an effective pathway. • The use of nickel ions, fly ash and sawdust to achieve the recycling utilization of resources. -- Abstract: This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid–solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH = 7 with a 2:1 liquid–solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03–0.1 min −1 ) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH = 7.0 compared with ozonation alone

  16. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wei, E-mail: chmawv@yahoo.com [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Zong, Panpan; Cheng, Zihong [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Baodong; Sun, Qi [National Institute of Clean-and-low Carbon Energy, Beijing 102209 (China)

    2014-02-15

    Highlights: • Biomass and fly ash which were widespread for adsorption of heavy metal ions. • Preparation of catalyst by saturated adsorbents for 2-chlorophenol ozone degradation. • This work demonstrated that the O{sub 3}/catalyst process was an effective pathway. • The use of nickel ions, fly ash and sawdust to achieve the recycling utilization of resources. -- Abstract: This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid–solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH = 7 with a 2:1 liquid–solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03–0.1 min{sup −1}) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH = 7.0 compared with ozonation alone.

  17. Biological Macro and Micro Systems Co-existing in the “Fountain of the Two Dragons”, Palermo

    Directory of Open Access Journals (Sweden)

    Enza Di Carlo

    2017-06-01

    Full Text Available Stone works of art located outdoors are exposed to natural deterioration, due to several physical, chemical and biological factors. Biological macro- and micro-systems (e.g. weeds, insects, algae, mosses, fungi and bacteria may induce the biodeterioration of stone materials. In February 2014, the state of conservation of the Fountain of the two Dragons in Palermo was examined, during which time biological colonization in some areas of the fountain and statues, was also detected. The monument represents an excellent substrate for the development and growth of microrganisms and organisms that need a continuous supply of water. Direct solar irradiance promotes the development of photoautotrophic organisms, bryophyte flora, in addition to several microbial genera, responsible for pigmentation, discoloring, efflorescence. After autotrophic colonization, some organisms find an ideal habitat also during wintertime, including two species of gastropods and two species of Hemiptera, omnivorous, a species of Collembola, mostly fungivorous. This interdisciplinary study has enabled the detection and identification of different biological communities, providing information for a subsequent project of preventive conservation of the fountain and its surroundings.

  18. 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.

  19. 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

  20. Catalytic exhaust control

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, H

    1973-09-01

    Recent achievements and problems in the development of exhaust control devices in the USA are reviewed. To meet the 1976 emission standards, catalytic systems for the oxidation of carbon monoxide and hydrocarbons and for the reduction of nitrogen oxides to nitrogen and water are needed. While oxidizing catalysts using platinum, palladium, copper, vanadium, and chromium appplied on alumina or ceramic materials are more or less effective in emission control, there are no catalytic devices for the reduction of nitrogen oxides with the required useful life of 25,000 to 50,000 miles as yet available. In the case of platinum catalysts on monolithic supports, the operating temperature of 650 to 750/sup 0/C as required for the oxidation process may cause inactivation of the catalysts and fusion of the support material. The oxidation of CO and hydrocarbons is inhibited by high concentrations of CO, nitric oxide, and hydrocarbons. The use of catalytic converters requires the use of lead-free or low-lead gasoline. The nitrogen oxides conversion efficiency is considerably influenced by the oxygen-to-CO ratio of the exhaust gas, which makes limitation of this ratio necessary.

  1. 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.

  2. Zap-70 positive chronic lymphocytic leukemia co-existing with Jak 2 V671F positive essential thrombocythemia: A common defective stem cell?

    OpenAIRE

    Tabaczewski, Piotr; Nadesan, Sushani; Lim, Seah H

    2008-01-01

    Essential thrombocythemia (ET) co-existing with chronic lymphocytic leukemia (CLL) is extremely rare. We report two cases of ET with Jak 2 V617F in Zap-70+ CLL. ET is a myeloproliferative stem cell disease. Zap-70 expression in CLL correlates with non-mutated immunoglobulin genes. The occurrence of a less mature CLL in patients with a pluripotential stem cell disease raises the possibility that an initial “trigger hit” occurred in a pre-Jak 2 common early progenitor in these patients. Subsequ...

  3. REM-sleep alterations in children with co-existence of tic disorders and attention-deficit/hyperactivity disorder: impact of hypermotor symptoms.

    Science.gov (United States)

    Kirov, Roumen; Banaschewski, Tobias; Uebel, Henrik; Kinkelbur, Jörg; Rothenberger, Aribert

    2007-06-01

    To characterize precisely the sleep pattern in children with co-existence of TD + ADHD. By means of polysomnography, sleep pattern was investigated in 19 children with TD + ADHD unmedicated before and during study and 19 healthy controls, matched for age, gender, and intelligence. Compared with healthy controls, children with TD + ADHD displayed shorter REM sleep latency and increased REM sleep duration. There was a negative correlational relationship between these REM-sleep alterations and they were determined by hyperactivity symptoms. Sleep in children with coexistence of TD + ADHD may be characterized by an elevated REM sleep drive. Common mechanisms are suggested to underpin hypermotor symptoms and REM sleep regulation.

  4. The burden of co-existing dermatological disorders and their tendency of being overlooked among patients admitted to muhimbili national hospital in Dar es Salaam, Tanzania

    Directory of Open Access Journals (Sweden)

    Chale Pauline NF

    2011-04-01

    Full Text Available Abstract Background Skin diseases are underestimated and overlooked by most clinicians despite being common in clinical practice. Many patients are hospitalized with co-existing dermatological conditions which may not be detected and managed by the attending physicians. The objective of this study was to determine the burden of co-existing and overlooked dermatological disorders among patients admitted to medical wards of Muhimbili National hospital in Dar es Salaam. Study design and settings A hospital-based descriptive cross-sectional study conducted at Muhimbili National hospital in Dar es Salaam, Tanzania. Methods Patients were consecutively recruited from the medical wards. Detailed interview to obtain clinico-demographic characteristics was followed by a complete physical examination. Dermatological diagnoses were made mainly clinically. Appropriate confirmatory laboratory investigations were performed where necessary. Data was analyzed using the 'Statistical Package for Social Sciences' (SPSS program version 10.0. A p-value of Results Three hundred and ninety patients admitted to medical wards were enrolled into the study of whom, 221(56.7% were females. The mean age was 36.7 ± 17.9 (range 7-84 years. Overall, 232/390 patients (59.5% had co-existing dermatological disorders with 49% (191/390 having one, 9% (36/390 two and 5 patients (1% three. A wide range of co-existing skin diseases was encountered, the most diverse being non-infectious conditions which together accounted for 36.4% (142/390 while infectious dermatoses accounted for 31.5% (123/390. The leading infectious skin diseases were superficial fungal infections accounting for 18%. Pruritic papular eruption of HIV/AIDS (PPE and seborrheic eczema were the most common non-infectious conditions, each accounting for 4.3%. Of the 232/390 patients with dermatological disorders, 191/232 (82.3% and 154/232 (66.3% had been overlooked by their referring and admitting doctors respectively

  5. Co-existence of Endometriotic Cyst of the Ovary and Arias-Stella Reaction in a Non-Pregnant Woman: Report of a Rare Case.

    Science.gov (United States)

    Harikrishnan, Volga; Esaki, Muthuvel; Srinivasan, Chitra; Arockiasamy, Parimala; Ethirajan, Shanthi

    2016-03-01

    Endometriosis is defined as presence of endometrial tissue outside the uterus. It can occur anywhere in the ovary. In the ovary it is usually presented as cyst, termed as endometriotic cyst or Chocolate cyst. Arias-Stella reaction is usually seen in gestational endometrium or in ectopic gestation site and rarely in non-pregnant uterus with hormonal intake. Co-existence of endometriosis and Arias-Stella reaction is very rare. We present a very rare case of endometriotic cyst of the ovary exhibiting Arias -Stella reaction which was seen in of non pregnant patient without any history of hormonal intake.

  6. Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity.

    Science.gov (United States)

    Hecht, K; Wrba, A; Jaenicke, R

    1989-07-15

    Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes.

  7. [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.

  8. 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.

  9. Two co-existing germline mutations P53 V157D and PMS2 R20Q promote tumorigenesis in a familial cancer syndrome.

    Science.gov (United States)

    Wang, Zuoyun; Sun, Yihua; Gao, Bin; Lu, Yi; Fang, Rong; Gao, Yijun; Xiao, Tian; Liu, Xin-Yuan; Pao, William; Zhao, Yun; Chen, Haiquan; Ji, Hongbin

    2014-01-01

    Germline mutations are responsible for familial cancer syndromes which account for approximately 5-10% of all types of cancers. These mutations mainly occur at tumor suppressor genes or genome stability genes, such as DNA repair genes. Here we have identified a cancer predisposition family, in which eight members were inflicted with a wide spectrum of cancer including one diagnosed with lung cancer at 22years old. Sequencing analysis of tumor samples as well as histologically normal specimens identified two germline mutations co-existing in the familial cancer syndrome, the mutation of tumor suppressor gene P53 V157D and mismatch repair gene PMS2 R20Q. We further demonstrate that P53 V157D and/or PMS2 R20Q mutant promotes lung cancer cell proliferation. These two mutants are capable of promoting colony formation in soft agar as well as tumor formation in transgenic drosophila system. Collectively, these data have uncovered the important role of co-existing germline P53 and PMS2 mutations in the familial cancer syndrome development. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  10. Global co-existence of two evolutionary lineages of parvovirus B19 1a, different in genome-wide synonymous positions.

    Directory of Open Access Journals (Sweden)

    Marijke W A Molenaar-de Backer

    Full Text Available Parvovirus B19 (B19V can cause infection in humans. To date, three genotypes of B19V, with subtypes, are known, of which genotype 1a is the most prevalent genotype in the Western world. We sequenced the genome of B19V strains of 65 asymptomatic, recently infected Dutch blood donors, to investigate the spatio-temporal distribution of B19V strains, in the years 2003-2009. The sequences were compared to B19V sequences from Dutch patients with fifth disease, and to global B19V sequences as available from GenBank. All Dutch B19V strains belonged to genotype 1a. Phylogenetic analysis of the strains from Dutch blood donors showed that two groups of genotype 1a co-exist. A clear-cut division into the two groups was also found among the B19V strains from Dutch patients, and among the B19V sequences in GenBank. The two groups of genotype 1a co-exist around the world and do not appear to differ in their ability to cause disease. Strikingly, the two groups of B19V predominantly differ in synonymous mutations, distributed throughout the entire genome of B19V. We propose to call the two groups of B19V genotype 1a respectively subtype 1a1 and 1a2.

  11. Fiber mediated receptor masking in non-infected bystander cells restricts adenovirus cell killing effect but promotes adenovirus host co-existence.

    Directory of Open Access Journals (Sweden)

    Johan Rebetz

    Full Text Available The basic concept of conditionally replicating adenoviruses (CRAD as oncolytic agents is that progenies generated from each round of infection will disperse, infect and kill new cancer cells. However, CRAD has only inhibited, but not eradicated tumor growth in xenograft tumor therapy, and CRAD therapy has had only marginal clinical benefit to cancer patients. Here, we found that CRAD propagation and cancer cell survival co-existed for long periods of time when infection was initiated at low multiplicity of infection (MOI, and cancer cell killing was inefficient and slow compared to the assumed cell killing effect upon infection at high MOI. Excessive production of fiber molecules from initial CRAD infection of only 1 to 2% cancer cells and their release prior to the viral particle itself caused a tropism-specific receptor masking in both infected and non-infected bystander cells. Consequently, the non-infected bystander cells were inefficiently bound and infected by CRAD progenies. Further, fiber overproduction with concomitant restriction of adenovirus spread was observed in xenograft cancer therapy models. Besides the CAR-binding Ad4, Ad5, and Ad37, infection with CD46-binding Ad35 and Ad11 also caused receptor masking. Fiber overproduction and its resulting receptor masking thus play a key role in limiting CRAD functionality, but potentially promote adenovirus and host cell co-existence. These findings also give important clues for understanding mechanisms underlying the natural infection course of various adenoviruses.

  12. The effects of aerobic exercise for persons with migraine and co-existing tension-type headache and neck pain. A randomized, controlled, clinical trial.

    Science.gov (United States)

    Krøll, Lotte Skytte; Hammarlund, Catharina Sjödahl; Linde, Mattias; Gard, Gunvor; Jensen, Rigmor Højland

    2018-01-01

    Aim To evaluate aerobic exercise in migraine and co-existing tension-type headache and neck pain. Methods Consecutively recruited persons with migraine and co-existing tension-type headache and neck pain were randomized into an exercise group or control group. Aerobic exercise consisted of bike/cross-trainer/brisk walking for 45 minutes, three times/week. Controls continued usual daily activities. Pain frequency, intensity, and duration; physical fitness, level of physical activity, well-being and ability to engage in daily activities were assessed at baseline, after treatment and at follow-up. Results Fifty-two persons completed the study. Significant between-group improvements for the exercise group were found for physical fitness, level of physical activity, migraine burden and the ability to engage in physical activity because of reduced impact of tension-type headache and neck pain. Within the exercise group, significant reduction was found for migraine frequency, pain intensity and duration, neck pain intensity, and burden of migraine; an increase in physical fitness and well-being. Conclusions Exercise significantly reduced the burden of migraine and the ability to engage in physical activity because of reduced impact of tension-type headache and neck pain. Exercise also reduced migraine frequency, pain intensity and duration, although this was not significant compared to controls. These results emphasize the importance of regular aerobic exercise for reduction of migraine burden.

  13. Co-existence of long-range order and spin fluctuation in a new geometric frustration series M2(OH)3Cl

    International Nuclear Information System (INIS)

    Zheng, X.G.; Hagihala, Masato; Toriyi, Takato

    2007-01-01

    Recently, we observed the co-existence of a long-range magnetic order and spin fluctuation in a clean compound of clinoatacamite, Cu 2 (OH) 3 Cl (PRL95 (2005) 057201). The present work reports magnetic studies on other compounds of this transition metal series M 2 (OH) 3 Cl, where M represents three-dimensional (3D)-electron magnetic ions of Co 2+ , Fe 2+ , etc., respectively. The present study shows that this co-existence is a common feature of the M 2 Cl(OH) 3 series, no matter whether it is anti-ferromagnetic, as in the case of Fe 2 (OH) 3 Cl (T N =15 K), or ferromagnetic, as in the case of Co 2 (OH) 3 Cl (T C =10.5 K). These compounds show a 3D network of corner-sharing tetrahedrons for the magnetic ions. The tetrahedron is slightly tilted with roughly 10% longer distance between the M-M bonded by Cl than those bonded by O and this distortion is suspected to be responsible for the partial order. This research suggests that the transition metal hydroxyhalide M 2 Cl(OH) 3 series are new geometric frustration system on tetrahedral lattice for d-electron spins

  14. 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

    Directory of Open Access Journals (Sweden)

    K Beart

    2013-07-01

    Full Text Available 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 learners were held. Valuable data, confirming the learners’ behaviour manifestation and serving as triangulation, was collected by using a projection test and a self-esteem questionnaire. Interviews and assessments were conducted to analyse the situation initially and again after the yoga intervention. Based on the data collected and analysed, the perception of parents and teachers was that to an extent yoga had a positive influence on the behaviour of learners with ADHD. Although no long-term influence of yoga is determined in this investigation, there is sufficient evidence to suggest that there is potential in using yoga to support learners with ADHD regarding concentration, aggression, anxiety and an improvement in self-esteem. Keywords: ADHD, aggression, anxiety, concentration, self-esteem, yoga

  15. Solitude or co-existence

    DEFF Research Database (Denmark)

    Sorensen, Elsebeth Korsgaard; Voldborg, Hanne

    2017-01-01

    This study reports on research into the impact of digital technological interventions for including kids with attention and developmental deficits into school class contexts. It describes, how the authors have approached the challenge of researching inclusion of kids with attention and developmen......This study reports on research into the impact of digital technological interventions for including kids with attention and developmental deficits into school class contexts. It describes, how the authors have approached the challenge of researching inclusion of kids with attention...

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

    KAUST Repository

    Sun, Ke; Saadi, Fadl H.; Lichterman, Michael F.; Hale, William G.; Wang, Hsinping; Zhou, Xinghao; Plymale, Noah T.; Omelchenko, Stefan T.; He, Jr-Hau; Papadantonakis, Kimberly M.; Brunschwig, Bruce S.; Lewis, Nathan S.

    2015-01-01

    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

  17. The impact of water concentration on the catalytic oxidation of ethanol on platinum electrode in concentrated phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, A.P.M.; Previdello, B.A.F.; Varela, H.; Gonzalez, E.R. [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, C.P. 780, CEP 13560-970 Sao Carlos, SP (Brazil)

    2010-01-15

    The electro-oxidation of ethanol on platinum in phosphoric acid opens the door to promote the oxidation reaction at higher temperatures. However, the effect of the presence of water is not well understood. In this work, the electro-oxidation of ethanol on platinum was studied in concentrated phosphoric acid containing different concentrations of water at room temperature. The results show that effect of bulk water on the rate electro-oxidation is highest at 0.60 V and decreases for increasing potentials. This was suggested as due to the increasing formation of oxygenated species on the electrode surface with potential, which in turn is more efficient than the increase of water content in the electrolyte. Altogether, these results were interpreted as an evidence of a Langmuir-Hinshelwood step involving oxygenated species as one of the adsorbed partners. (author)

  18. Characterization of a trinuclear ruthenium species in catalytic water oxidation by Ru(bda)(pic)2 in neutral media.

    Science.gov (United States)

    Zhang, Biaobiao; Li, Fei; Zhang, Rong; Ma, Chengbing; Chen, Lin; Sun, Licheng

    2016-06-30

    A Ru(III)-O-Ru(IV)-O-Ru(III) type trinuclear species was crystallographically characterized in water oxidation by Ru(bda)(pic)2 (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; pic = 4-picoline) under neutral conditions. The formation of a ruthenium trimer due to the reaction of Ru(IV)[double bond, length as m-dash]O with Ru(II)-OH2 was fully confirmed by chemical, electrochemical and photochemical methods. Since the oxidation of the trimer was proposed to lead to catalyst decomposition, the photocatalytic water oxidation activity was rationally improved by the suppression of the formation of the trimer.

  19. The symbiotic relationship between dominant canopy trees and soil microbes affects the nitrogen source utilization of co-existing understory trees

    Science.gov (United States)

    Iwaoka, C.; Hyodo, F.; Taniguchi, T.; Shi, W.; Du, S.; Yamanaka, N.; Tateno, R.

    2017-12-01

    The symbiotic relationship between dominant canopy trees and soil microbes such as mycorrhiza or nitrogen (N) fixer are important determinants of soil N dynamics of a forest. However, it is not known how and to what extent the symbiotic relationship of dominant canopy trees with soil microbes affect the N source of co-existing trees in forest. We measured the δ15N of surface soils (0-10 cm), leaves, and roots of the dominant canopy trees and common understory trees in an arbuscular mycorrhizal N-fixing black locust (Robinia pseudoacacia) plantation and an ectomycorrhizal oak (Quercus liaotungensis) natural forest in a China dryland. We also analyzed the soil dissolved N content in soil extracts and absorbed by ion exchange resin, and soil ammonia-oxidizer abundance using real-time PCR. The δ15N of soil and leaves were higher in the black locust forest than in the oak forest, although the δ15N of fine roots was similar in the two forests, in co-existing understory trees as well as dominant canopy trees. Accordingly, the δ15N of leaves was similar to or higher than that of fine roots in the black locust forest, whereas it was consistently lower than that of fine roots in the oak forest. In the black locust forest, the soil dissolved organic N and ammonium N contents were less abundant but the nitrate N contents in soils and absorbed by the ion exchange resin and ammonia-oxidizer abundance were greater, due to N fixation or less uptake of organic N from arbuscular mycorrhiza. In contrast, the soil dissolved organic N and ammonium N contents were more abundant in the oak forest, whereas the N content featured very low nitrate, due to ectomycorrhizal ability to access organic N. These results suggest that the main N source is nitrate N in the black locust forest, but dissolved organic N or ammonium N in the oak forest. N fixation or high N loss due to high N availability would cause high δ15N in soil and leaves in black locust forest. On the other hand, low soil N

  20. Level of physical activity, well-being, stress and self-rated health in persons with migraine and co-existing tension-type headache and neck pain

    DEFF Research Database (Denmark)

    Krøll, Lotte Skytte; Hammarlund, Catharina Sjödahl; Westergaard, Maria Lurenda

    2017-01-01

    where questionnaires on physical activity, psychological well-being, perceived stress and self-rated health were completed by 148 persons with migraine and 100 healthy controls matched by sex and average age. Semi-structured interviews were conducted to assess characteristics of migraine, tension......-existing tension-type headache and neck pain in a clinic-based sample, b) the level of physical activity, psychological well-being, perceived stress and self-rated health in persons with migraine and co-existing tension-type headache and neck pain compared to healthy controls, c) the perceived ability of persons...... well-being, higher level of perceived stress and poorer self-rated health compared to healthy controls. They reported reduced ability to perform physical activity owing to migraine (high degree), tension-type headache (moderate degree) and neck pain (low degree). The most burdensome condition...

  1. Under-coding of secondary conditions in coded hospital health data: Impact of co-existing conditions, death status and number of codes in a record.

    Science.gov (United States)

    Peng, Mingkai; Southern, Danielle A; Williamson, Tyler; Quan, Hude

    2017-12-01

    This study examined the coding validity of hypertension, diabetes, obesity and depression related to the presence of their co-existing conditions, death status and the number of diagnosis codes in hospital discharge abstract database. We randomly selected 4007 discharge abstract database records from four teaching hospitals in Alberta, Canada and reviewed their charts to extract 31 conditions listed in Charlson and Elixhauser comorbidity indices. Conditions associated with the four study conditions were identified through multivariable logistic regression. Coding validity (i.e. sensitivity, positive predictive value) of the four conditions was related to the presence of their associated conditions. Sensitivity increased with increasing number of diagnosis code. Impact of death on coding validity is minimal. Coding validity of conditions is closely related to its clinical importance and complexity of patients' case mix. We recommend mandatory coding of certain secondary diagnosis to meet the need of health research based on administrative health data.

  2. Co-existence of ischemic stroke in Rheumatic and non-rheumatic atrial Fibrillation in a tertiary care teaching hospital of Western Nepal

    Directory of Open Access Journals (Sweden)

    Ram Chandra Kafle

    2017-12-01

    Full Text Available Background & Objectives: Stroke is a major public health burden worldwide leading to long-term morbidity and even mortality. Atrial fibrillation (AF is the most common sustained arrhythmia and is an independent factor to increase risk of ischemic stroke. The risk of stroke further enhanced in rheumatic atrial fibrillation and affects younger population of developing countries.  The study has aimed to find out frequency of co-existence of stroke in AF and secondarily to look for age distribution of stroke and risk factors of AF.Materials & Methods: A retrospective analysis of trans-thoracic echocardiographic records of patients from 1st June 2009 to 31st June 2016 was done. Data were collected in a pre-structured proforma and analyzed.Results: Among 15767 echocardiographies, 577 (3.65% cases were recorded to have atrial fibrillation. Mean age 65(±15 years ranging from 14 to 100 years. Rheumatic heart disease was the second most common cause of atrial fibrillation after hypertension. The co-existence of ischemic stroke was seen in 87(15.07% cases with male to female ratio of 1:1.3. The proportion of stroke in rheumatic Atrial fibrillation was 21(18.75% which was higher than in non-Rheumatic atrial fibrillation 66(14.2%.Conclusion: Rheumatic heart disease is contributing as second most common cause of atrial fibrillation after hypertension, nearly one fourth of total stroke and most common (93% cause of stroke below the age of 45 years. Preventive strategies aimed at health awareness about rheumatic fever, screening programs at community level, early detection and treatment for hypertension and Rheumatic heart disease can contribute in reduction of stroke burden. 

  3. 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.

  4. Ontogeny of the VIP system in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum: successive appearance of co-existing PACAP and NOS.

    Science.gov (United States)

    Badawy, Gamal; Reinecke, Manfred

    2003-03-01

    Evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and nitric oxide synthase (NOS) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. This immunofluorescence study aims to clarify the appearance and localization of VIP, PACAP and NOS in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum, during ontogeny. VIP-immunoreactivity appeared in nerve fibers as early as on day 3 after hatching likely indicating a particular role, such as a trophic action, of VIP in very early development. PACAP-immunoreactivity was observed 3 days later within the VIP-immunoreactive (-IR) fibers. From this time on, VIP- and PACAP-immunoreactivity exhibited complete co-existence. VIP/PACAP-IR fibers were found throughout the gastro-intestinal tract. They were most prominent in the myenteric plexus and the muscle layers and less frequent in the submucosa. NOS-immunoreactivity appeared as late as at the 1st (64 days) juvenile stage in a subpopulation of the VIP/PACAP-IR fibers that contacted submucosal arteries. We found only very few VIP/PACAP-IR perikarya, indicating that part of the VIP/PACAP-IR fibers is of extrinsic origin. On day 12 and in the 1st and 2nd (104 days) juvenile stage, infrequent PACAP-IR entero-endocrine cells were noted, while neither VIP- nor NOS-immunoreactivity occurred in endocrine cells at any stage of development. The complete coexistence of neuronal PACAP- and VIP-immunoreactivities and their very early appearance in ontogeny may suggest important and coordinated roles of both peptides in the control of Axolotl gastro-intestinal activity, while the VIP/ PACAP/NOS-IR fibers may be involved in the regulation of submucosal blood flow.

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

    Science.gov (United States)

    Sun, Ke; Saadi, Fadl H; Lichterman, Michael F; Hale, William G; Wang, Hsin-Ping; Zhou, Xinghao; Plymale, Noah T; Omelchenko, Stefan T; He, Jr-Hau; Papadantonakis, Kimberly M; Brunschwig, Bruce S; Lewis, Nathan S

    2015-03-24

    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).

  6. 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.

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

    Czech Academy of Sciences Publication Activity Database

    Lukeš, Petr; Člupek, Martin; Babický, Václav; Sisrová, I.; Janda, V.

    2011-01-01

    Roč. 20, č. 3 (2011), 034011-034011 ISSN 0963-0252 R&D Projects: GA AV ČR IAAX00430802; GA ČR(CZ) GD104/09/H080 Institutional research plan: CEZ:AV0Z20430508 Keywords : corona discharge * water * erosion * tungsten * hydrogen peroxide * dimethylsulfoxide Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2011 http://www.ipp.cas.cz/Ips/public/lukes_2011a.pdf

  8. Preliminary radiation-oxidizing treatment influence on radiation-catalytic activity of zirconium during water decomposition process

    International Nuclear Information System (INIS)

    Garibov, A.A.; Aliyev, A.G.; Agayev, T.N.; Aliyev, S.M.; Velibekova, G.Z.

    2004-01-01

    The study of physical-chemical processes proceeding in contact of metal constructional materials nuclear reactors with water at simultaneous influence of temperature and radiation represents the large interest at the decision of problems material authority and safety of work of nuclear -power installations [1-2]. One of the widely widespread materials of active zone nuclear reactors is metal zirconium and its alloys. The influence of preliminary radiation processing on radiation, radiation -thermal and thermal processes of accumulation of molecular hydrogen and oxidation zirconium in contact with water is investigated at T=673 K and ρ=5mg/sm 3 [3-4]. Initial samples zirconium previously has been exposed by an irradiation in medium H 2 O 2 at D=20-410 kGy. The contribution of radiation processes in these contacts in process thermo-radiation decomposition of water and oxidation of materials of zirconium is revealed. It is established that the interaction of Zr metal, preliminary treated by radiation, with water at radiation -heterogeneous processes leads to passivity of a surface. The rate meanings of thermal, radiation -thermal processes and radiation-chemical yields of hydrogen are determined. It is revealed, that at radiation-heterogeneous processes in system Zr +H 2 O (ρ =5mg/sm 3 T=673 K) the increase of the absorbed doze up to 123 kGy results to reduction of a radiation -chemical yield of molecular hydrogen. The further increase of the absorbed doze results to increase of a radiation -chemical yield of hydrogen. The observable effect at the preliminary radiation of zirconium is connected to formation of oxide phase on a surface. The mechanism of radiation -heterogeneous processes proceeding in system Zr+H 2 O is suggested. (author)

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

    Directory of Open Access Journals (Sweden)

    Bernardo Castro-Dominguez

    2016-09-01

    Full Text Available 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.

  10. 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. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. 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.

  12. 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.

  13. Effect of iron content on the catalytic activity of Fe-MnOx electrodeposited films in water oxidation

    Science.gov (United States)

    Selinger, Elizabeth; Ryczko, Kevin; Lopinski, Gregory; Armandi, Marco; Bonelli, Barbara; Tamblyn, Isaac

    We report on the experimental and computational optimization and characterization of an MnOx structure containing a small amount of Fe, used as a catalyst for the water oxidation reaction (WOR), the key limiting reaction in water splitting. MnOx materials are earth-abundant and known to be efficient for WOR, and the method of cathodically electrodepositing catalysts allows for quick synthesis and a homogeneous coverage of the substrate. We present an increase in WOR activity due to the presence of Fe in this MnOx catalyst structure. First, we explored the optimal range for Fe(NO3)3 concentration in an KMnO4 solution for electrodeposition and tested for WOR activity. The catalyst structure was then analyzed using FESEM, XPS, and a Kelvin probe. We then developed a computational model of this structure, using density functional theory to obtain adsorption energies, work functions, projected density of states, and Born-Oppenheimer molecular dynamics. In this theoretical framework, we explore how these observables change with respect to concentration of Fe, and compare the theoretical model with experiment. special acknowledgement to the Italian Cultural Centre of Durham scholarship program.

  14. Polar aprotic solvent-water mixture as the medium for catalytic production of hydroxymethylfurfural (HMF) from bread waste.

    Science.gov (United States)

    Yu, Iris K M; Tsang, Daniel C W; Chen, Season S; Wang, Lei; Hunt, Andrew J; Sherwood, James; De Oliveira Vigier, Karine; Jérôme, François; Ok, Yong Sik; Poon, Chi Sun

    2017-12-01

    Valorisation of bread waste for hydroxymethylfurfural (HMF) synthesis was examined in dimethyl sulfoxide (DMSO)-, tetrahydrofuran (THF)-, acetonitrile (ACN)-, and acetone-water (1:1v/v), under heating at 140°C with SnCl 4 as the catalyst. The overall rate of the process was the fastest in ACN/H 2 O and acetone/H 2 O, followed by DMSO/H 2 O and THF/H 2 O due to the rate-limiting glucose isomerisation. However, the formation of levulinic acid (via rehydration) and humins (via polymerisation) was more significant in ACN/H 2 O and acetone/H 2 O. The constant HMF maxima (26-27mol%) in ACN/H 2 O, acetone/H 2 O, and DMSO/H 2 O indicated that the rates of desirable reactions (starch hydrolysis, glucose isomerisation, and fructose dehydration) relative to undesirable pathways (HMF rehydration and polymerisation) were comparable among these mediums. They also demonstrated higher selectivity towards HMF production over the side reactions than THF/H 2 O. This study differentiated the effects of polar aprotic solvent-water mediums on simultaneous pathways during biomass conversion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

    Science.gov (United States)

    Zhang, Yanzong; Zheng, Jingtang; Qu, Xianfeng; Yu, Weizhao; Chen, Honggang

    2008-06-01

    Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H2O2 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

  16. Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

    International Nuclear Information System (INIS)

    Zhang Yanzong; Zheng Jingtang; Qu Xianfeng; Yu Weizhao; Chen Honggang

    2008-01-01

    Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H 2 O 2 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

  17. 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  

  18. 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). Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. C-reactive protein is differentially modulated by co-existing infections, vitamin deficiencies and maternal factors in pregnant and lactating indigenous Panamanian women.

    Science.gov (United States)

    González-Fernández, Doris; Pons, Emérita Del Carmen; Rueda, Delfina; Sinisterra, Odalis Teresa; Murillo, Enrique; Scott, Marilyn E; Koski, Kristine G

    2017-06-02

    The usefulness of C-reactive protein (CRP) as a non-specific marker of inflammation during pregnancy and lactation is unclear in impoverished populations where co-existing infections and vitamin deficiencies are common. This cross-sectional study in Panama recruited 120 pregnant and 99 lactating Ngäbe-Buglé women from 14 communities in rural Panama. Obstetric history, indoor wood smoke exposure, fieldwork, BMI, vitamins A, B 12 , D, and folic acid, and inflammation markers (CRP, neutrophil/lymphocyte ratio (NLR), plateletcrit and cytokines) were measured. Multiple regressions explored both associations of CRP with other inflammatory markers and associations of CRP and elevated CRP based on trimester-specific cut-offs with maternal factors, infections and vitamin deficiencies. CRP was higher in pregnancy (51.4 ± 4.7 nmol/L) than lactation (27.8 ± 3.5 nmol/L) and was elevated above trimester specific cut-offs in 21% of pregnant and 30% of lactating women. Vitamin deficiencies were common (vitamin A 29.6%; vitamin D 68.5%; vitamin B 12 68%; folic acid 25.5%) and over 50% of women had two or more concurrent deficiencies as well as multiple infections. Multiple regression models highlighted differences in variables associated with CRP between pregnancy and lactation. In pregnancy, CRP was positively associated with greater indoor wood smoke exposure, caries and hookworm and negatively associated with Ascaris and vaginal Lactobacillus and Bacteroides/Gardnerella scores. Consistent with this, greater wood smoke exposure, caries as well as higher diplococcal infection score increased the odds of trimester-elevated CRP concentrations whereas longer gestational age lowered the likelihood of a trimester-elevated CRP. During lactation, folic acid deficiency was associated with higher CRP whereas parity, number of eosinophils and Mobiluncus score were associated with lower CRP. Also, a higher BMI and Trichomonas vaginalis score increased the likelihood of an

  20. A study of pharmacokinetic interactions among co-existing ingredients in Viscum coloratum after intravenous administration of three different preparations to rats.

    Science.gov (United States)

    Ma, Yuying; Fan, Ronghua; Duan, Mengmeng; Yu, Zhiguo; Zhao, Yunli

    2015-01-01

    Viscum coloratum (Komar) Nakai, known as Hujisheng in china, has been widely used as a herb medicine to treat a variety of diseases, including cardiovascular diseases, cancer, hypertension, hepatitis and hemorrhage. The aim was to investigate pharmacokinetic interactions among co-existing ingredients in V. coloratum after intravenous administration of three different preparations (four monomer solutions, the mixture of them and Viscum coloratum extracts) to rats. After protein precipitation pretreatment with plasma samples, high performance liquid chromatographic methods were developed and applied to quantitatively determinate the four components [syringin (Syri), homoeriodictyol-7-O-β-D-glycoside (Hedt-III), homoeriodictyol-7-O-β-D-apiose (1 → 2)-β-D-glycoside (Hedt-II) and homoeriodictyol-7-O-β-D-apiosiyl-(1 → 5)-β-D-apiosyl-(1 → 2)-β-D-glycoside (Hedt-I)]. The pharmacokinetic parameters (Area under the curve [AUC(0-t)], AUC(0-∞), t 1/2) were calculated using DAS 2.1 software (Chinese Pharmacological Society, Shanghai, China) and compared statistically by One-way analysis of variance using SPSS software (18.0, Chicago, IL, USA) with P dialectic view in the research and development processes.

  1. Co-existence of Anaerobic Ammonium Oxidation Bacteria and Denitrifying Anaerobic Methane Oxidation Bacteria in Sewage Sludge: Community Diversity and Seasonal Dynamics.

    Science.gov (United States)

    Xu, Sai; Lu, Wenjing; Mustafa, Muhammad Farooq; Caicedo, Luis Miguel; Guo, Hanwen; Fu, Xindi; Wang, Hongtao

    2017-11-01

    Anaerobic ammonium oxidation (ANAMMOX) and denitrifying anaerobic methane oxidation (DAMO) have been recently discovered as relevant processes in the carbon and nitrogen cycles of wastewater treatment plants. In this study, the seasonal dynamics of ANAMMOX and DAMO bacterial community structures and their abundance in sewage sludge collected from wastewater treatment plants were analysed. Results indicated that ANAMMOX and DAMO bacteria co-existed in sewage sludge in different seasons and their abundance was positively correlated (P bacteria in autumn and winter indicated that these seasons were the preferred time to favour the growth of ANAMMOX and DAMO bacteria. The community structure of ANNAMOX and DAMO bacteria could also shift with seasonal changes. The "Candidatus Brocadia" genus of ANAMMOX bacteria was mainly recovered in spring and summer, and an unknown cluster was primarily detected in autumn and winter. Similar patterns of seasonal variation in the community structure of DAMO bacteria were also observed. Group B was the dominant in spring and summer, whereas in autumn and winter, group A and group B presented almost the same proportion. The redundancy analysis revealed that pH and nitrate were the most significant factors affecting community structures of these two groups (P < 0.01). This study reported the diversity of ANAMMOX and DAMO in wastewater treatment plants that may be the basis for new nitrogen removal technologies.

  2. Co-existence of Blau syndrome and NAID? Diagnostic challenges associated with presence of multiple pathogenic variants in NOD2 gene: a case report.

    Science.gov (United States)

    Dziedzic, Magdalena; Marjańska, Agata; Bąbol-Pokora, Katarzyna; Urbańczyk, Anna; Grześk, Elżbieta; Młynarski, Wojciech; Kołtan, Sylwia

    2017-07-27

    Pediatric autoinflammatory diseases are rare and still poorly understood conditions resulting from defective genetic control of innate immune system, inter alia from anomalies of NOD2 gene. The product of this gene is Nod2 protein, taking part in maintenance of immune homeostasis. Clinical form of resultant autoinflammatory condition depends on NOD2 genotype; usually patients with NOD2 defects present with Blau syndrome, NOD2-associated autoinflammatory disease (NAID) or Crohn's disease. We present the case of a 7-year-old girl with co-existing symptoms of two rare diseases, Blau syndrome and NAID. Overlapping manifestations of two syndromes raised a significant diagnostic challenge, until next-generation molecular test (NGS) identified presence of three pathogenic variants of NOD2 gene: P268S, IVS8 +158 , 1007 fs, and established the ultimate diagnosis. Presence of multiple genetical abnormalities resulted in an ambiguous clinical presentation with overlapping symptoms of Blau syndrome and NAID. Final diagnosis of autoinflammatory disease opened new therapeutic possibilities, including the use of biological treatments.

  3. The regulation of aortic endothelial cells by purines and pyrimidines involves co-existing P2y-purinoceptors and nucleotide receptors linked to phospholipase C.

    Science.gov (United States)

    Wilkinson, G F; Purkiss, J R; Boarder, M R

    1993-03-01

    1. We have examined the phospholipase C responses in bovine aortic endothelial cells to purines (ATP, ADP and analogues) and the pyrimidine, uridine triphosphate (UTP). 2. The cells responded to purines in a manner consistent with the presence of P2y purinoceptors; both 2-methylthioadenosine 5'-triphosphate (2MeSATP) and adenosine 5'-0-(2-thiodiphosphate) (ADP beta S) were potent agonists (EC50 0.41 microM and 0.85 microM respectively) while beta, gamma-methylene ATP at 300 microM was not. 3. The cells also responded to UTP. The maximal response to UTP was less than that for either 2MeSATP and ADP beta S while adenosine 5'-0-(3-thiotriphosphate) (ATP gamma S) gave the largest maximal response. 4. The concentration-effect curve to UTP was additive in the presence of either 2MeSATP or ADP beta S. However, the concentration-effect curves to ATP gamma S reached the same maximum in the presence or absence of UTP. 5. Suramin, at concentrations between 10 microM and 100 microM was a competitive antagonist for the response to ADP beta S and 2MeSATP but not the response to UTP. 6. The results show that there are two separate, co-existing, receptor populations: P2y-purinoceptors (responding to purines) and nucleotide receptors (responding to both purines and pyrimidines). We conclude that purines such as ATP/ADP may regulate aortic endothelial cells by interacting with two phospholipase C-linked receptors.

  4. New self-assembled material based on Ru nanoparticles and 4-sulfocalix[4]arene as an efficient and recyclable catalyst for reduction of brilliant yellow azo dye in water: a new model catalytic reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rambabu, Darsi; Pradeep, Chullikkattil P.; Dhir, Abhimanew, E-mail: abhimanew@iitmandi.ac.in [Indian Institute of Technology (India)

    2016-12-15

    New self-assembled material (Ru@SC) with ruthenium nanoparticles (Ru NPs) and 4-sulfocalix[4]arene (SC) is synthesized in water at room temperature. Ru@SC is characterized by thermal gravimetric analysis, FT-IR, powder x-ray diffraction, TEM and SEM analysis. The size of Ru nanoparticles in the self-assembly is approximately 5 nm. The self-assembled material Ru@SC shows an efficient catalytic reduction of toxic ‘brilliant yellow’ (BY) azo dye. The reduced amine products were successfully separated and confirmed by single-crystal XRD, NMR and UV-Vis spectroscopy. Ru@SC showed a better catalytic activity in comparison with commercial catalysts Ru/C (ruthenium on charcoal 5 %) and Pd/C (palladium on charcoal 5 and 10 %). The catalyst also showed a promising recyclability and heterogeneous nature as a catalyst for reduction of ‘BY’ azo dye.

  5. Dynamics of co-existing Escherichia colilineages in situ of the infant gut and multiplex phenotypic targeted recovery of previously uncultivated bacteria from the human gut

    DEFF Research Database (Denmark)

    Gumpert, Heidi

    The work in this thesis explores the dynamic nature of Escherichia coli lineages co-existing in the human intestinal tract. The work is supported via full genomesequencing of co-existing E. coli strains isolated from infants enrolled in the ALLERGYFLORA study. Both sets of isolates examined here...... were selected due to an observed change in their antibiotic susceptibility profile. Via full genome sequencing, we identified that in both cases a conjugative plasmid harboring antibiotic resistance genes was transferred between co-existing E. coli lineages and is responsible for the change...... in antibiotic susceptibility. In one case, the transfer occurred in the absenceof antibiotic treatment and the transconjugant remained amongst the gut microbiota for months, providing evidence to the hypothesis that resistance genes are stably maintained once acquired. To our knowledge, this is the first...

  6. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    Science.gov (United States)

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Synthesis and application of iron and zinc doped biochar for removal of p-nitrophenol in wastewater and assessment of the influence of co-existed Pb(II)

    International Nuclear Information System (INIS)

    Wang, Pei; Tang, Lin; Wei, Xue; Zeng, Guangming; Zhou, Yaoyu; Deng, Yaocheng; Wang, Jingjing; Xie, Zhihong; Fang, Wei

    2017-01-01

    Highlights: • Iron and zinc doped biochar was developed with larger specific surface area, new generated hydroxyl groups, and beneficial magnetism compared with pristine biochar. • Fe/Zn-biochar presented good performance both for PNP and Pb(II) adsorption as well as their simultaneous removal. • Mechanism of the enhanced adsorption for low concentrations of co-existing PNP and Pb(II) was proposed. - Abstract: The modification of biochar as a low-cost adsorbent is essential to improve its surface properties and shows great potential in water decontamination. The iron and zinc doped sawdust biochar (Fe/Zn-biochar) with large apparent surface area (518.54 m 2 /g) proposed in this work showed good performance for p-nitrophenol (PNP) removal compared with the pristine biochar (P-biochar), iron doped biochar (Fe-biochar) and zinc doped biochar (Zn-biochar) respectively. The batch experiments turned out that Fe/Zn-biochar exhibited larger PNP adsorption capacity under acidic pH solution, and the ionic strength had slightly negative impact on PNP adsorption. The adsorption kinetics and isotherms were discussed, and the experimental data fitted well the Pseudo-second-order equation and Langmuir model. The thermodynamic study indicated that the PNP adsorption was a spontaneous endothermic process. Furthermore, the simultaneous removal for PNP and Pb(II) by Fe/Zn-biochar was investigated. It implied that the adsorption of PNP and Pb(II) at their low concentration might be enhanced by the complexing-bridging mechanism of PNP and Pb(II) ascribing to the affinity between PNP and hydrophobic sites, in addition to the affinity between Pb(II) and oxygen-containing hydrophilic sites on Fe/Zn-biochar surface. However, the predominated competition between PNP and Pb(II) at their high concentrations with Fe/Zn-biochar suppressed their adsorption.

  8. Synthesis and application of iron and zinc doped biochar for removal of p-nitrophenol in wastewater and assessment of the influence of co-existed Pb(II)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Pei [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China); Tang, Lin, E-mail: tanglin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China); Wei, Xue [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China); Zhou, Yaoyu [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China); College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Deng, Yaocheng; Wang, Jingjing; Xie, Zhihong; Fang, Wei [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, Hunan (China)

    2017-01-15

    Highlights: • Iron and zinc doped biochar was developed with larger specific surface area, new generated hydroxyl groups, and beneficial magnetism compared with pristine biochar. • Fe/Zn-biochar presented good performance both for PNP and Pb(II) adsorption as well as their simultaneous removal. • Mechanism of the enhanced adsorption for low concentrations of co-existing PNP and Pb(II) was proposed. - Abstract: The modification of biochar as a low-cost adsorbent is essential to improve its surface properties and shows great potential in water decontamination. The iron and zinc doped sawdust biochar (Fe/Zn-biochar) with large apparent surface area (518.54 m{sup 2}/g) proposed in this work showed good performance for p-nitrophenol (PNP) removal compared with the pristine biochar (P-biochar), iron doped biochar (Fe-biochar) and zinc doped biochar (Zn-biochar) respectively. The batch experiments turned out that Fe/Zn-biochar exhibited larger PNP adsorption capacity under acidic pH solution, and the ionic strength had slightly negative impact on PNP adsorption. The adsorption kinetics and isotherms were discussed, and the experimental data fitted well the Pseudo-second-order equation and Langmuir model. The thermodynamic study indicated that the PNP adsorption was a spontaneous endothermic process. Furthermore, the simultaneous removal for PNP and Pb(II) by Fe/Zn-biochar was investigated. It implied that the adsorption of PNP and Pb(II) at their low concentration might be enhanced by the complexing-bridging mechanism of PNP and Pb(II) ascribing to the affinity between PNP and hydrophobic sites, in addition to the affinity between Pb(II) and oxygen-containing hydrophilic sites on Fe/Zn-biochar surface. However, the predominated competition between PNP and Pb(II) at their high concentrations with Fe/Zn-biochar suppressed their adsorption.

  9. 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.

  10. A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation. Annual progress report, September 15, 1996 - September 14, 1997

    International Nuclear Information System (INIS)

    Sen, A.

    1997-01-01

    'During the first year, the palladium-catalyzed deep oxidation of toxic organics by dioxygen in aqueous solution was examined in some detail. The research performed has established the viability of the catalytic system to effect the deep (and complete) oxidation of a very wide range of organic substrates under mild conditions. One significant observation was that chemical warfare agent models containing phosphorus-carbon and sulfur-carbon bonds could be eliminated by using this procedure.'

  11. SHORT COMMUNICATION CATALYTIC KINETIC ...

    African Journals Online (AJOL)

    IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of ...

  12. Catalytic distillation process

    Science.gov (United States)

    Smith, L.A. Jr.

    1982-06-22

    A method is described 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.

  13. Catalytic distillation structure

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-04-17

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

  14. CATALYTIC SPECTROPHOTOMETRIC DETERMINATION OF Mn(II ...

    African Journals Online (AJOL)

    Preferred Customer

    method is based on the catalytic effect of Mn(II) with the oxidation of Celestine blue .... water samples were filtered through a 0.45 μm pore size membrane filter to remove suspended .... slope of the calibration graph as the optimization criterion. ..... In presence of Phen as stability enhancement agent in indicator system. ( ) +.

  15. Catalytic nanoporous membranes

    Science.gov (United States)

    Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

    2013-08-27

    A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

  16. Steam reformer with catalytic combustor

    Science.gov (United States)

    Voecks, Gerald E. (Inventor)

    1990-01-01

    A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

  17. Summer co-existence of small-sized cyprinid and percid individuals in natural and impounded stretches of a lowland river: food niche partitioning among fishes.

    Science.gov (United States)

    Lik, J; Dukowska, M; Grzybkowska, M; Leszczyńska, J

    2017-04-01

    Due to changes of discharge regime downstream of a dam reservoir, an alluvial natural stretch of the Warta River changed to a macrophyte-dominated ecosystem. Large patches of submersed, aquatic macrophytes appeared in summer and their effect is analysed in this study. These patches contained enriched macroinvertebrate assemblages (epiphyton and benthos) and they were refuge for both zooplankton and young fishes released from the reservoir. Despite these altered conditions in this stretch, roach Rutilus rutilus, perch Perca fluviatilis and ruffe Gymnocephalus cernua dominated, as they did in the natural backwater. Fishes were sampled every 2 weeks from June to August, together with their food resources to assess the partitioning of the diet among small individuals of the three species in both stretches (the natural and affected ones). The aim of the analysis was to answer how animal food associated with water plants was partitioned between the species. In both stretches, G. cernua were primarily benthivorous, but epiphytic fauna, zooplankton and large-sized benthic chironomid larvae replaced lack of many large, benthic insects in the tailwater. Levins' food breath index decreased from 0·36 in the backwater to 0·29 in the tailwater. An opposite trend was observed for P. fluviatilis occurring among macrophytes. Perca fluviatilis were competitors of R. rutilus and took food not only in or on the river bed, but also in the water column. They ate zooplankton and epiphytic fauna and Levins' index increased from 0·32 to 0·44 in the tailwater. Rutilus rutilus fed on adult insects, algae and plant fragments in the natural stretch. In the tailwater, these food types were chiefly complemented by zooplankton. Despite this, the niche breadth of R. rutilus was similar at the two sites. Abundance of food associated with the macrophytes appeared to facilitate cohabitation in the abundant fish populations, but P. fluviatilis appeared to benefit the most in the altered river

  18. Catalytic pyrolysis of hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Vail' eva, N A; Buyanov, R A

    1979-01-01

    Catalytic pyrolysis of petroleum fractions (undecane) was performed with the object of clarifying such questions as the mechanism of action of the catalyst, the concepts of activity and selectivity of the catalyst, the role of transport processes, the temperature ranges and limitations of the catalytic process, the effect of the catalyst on secondary processes, and others. Catalysts such as quartz, MgO, Al/sub 2/O/sub 3/, were used. Analysis of the experimental findings and the fact that the distribution of products is independent of the nature of the surface, demonstrate that the pyrolysis of hydrocarbons in the presence of catalysts is based on the heterogeneous-homogeneous radical-chain mechanism of action, and that the role of the catalysts reduces to increasing the concentration of free radicals. The concept of selectivity cannot be applied to catalysts here, since they do not affect the mechanism of the unfolding of the process of pyrolysis and their role consists solely in initiating the process. In catalytic pyrolysis the concepts of kinetic and diffusive domains of unfolding of the catalytic reaction do not apply, and only the outer surface of the catalyst is engaged, whereas the inner surface merely promotes deletorious secondary processes reducing the selectivity of the process and the activity of the catalyst. 6 references, 2 figures.

  19. 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...

  20. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Preferred Customer

    acetylchlorophosphonazo(CPApA) by hydrogen peroxide in 0.10 M phosphoric acid. A novel catalytic kinetic-spectrophotometric method is proposed for the determination of copper based on this principle. Copper(II) can be determined spectrophotometrically ...

  1. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

    1998-01-01

    Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

  2. Iridium complexes containing mesoionic C donors: selective C(sp3)-H versus C(sp2)-H bond activation, reactivity towards acids and bases, and catalytic oxidation of silanes and water.

    Science.gov (United States)

    Petronilho, Ana; Woods, James A; Mueller-Bunz, Helge; Bernhard, Stefan; Albrecht, Martin

    2014-11-24

    Metalation of a C2-methylated pyridylimidazolium salt with [IrCp*Cl2]2 affords either an ylidic complex, resulting from C(sp(3))-H bond activation of the C2-bound CH3 group if the metalation is performed in the presence of a base, such as AgO2 or Na2CO3, or a mesoionic complex via cyclometalation and thermally induced heterocyclic C(sp(2))-H bond activation, if the reaction is performed in the absence of a base. Similar cyclometalation and complex formation via C(sp(2))-H bond activation is observed when the heterocyclic ligand precursor consists of the analogous pyridyltriazolium salt, that is, when the metal bonding at the C2 position is blocked by a nitrogen rather than a methyl substituent. Despite the strongly mesoionic character of both the imidazolylidene and the triazolylidene, the former reacts rapidly with D(+) and undergoes isotope exchange at the heterocyclic C5 position, whereas the triazolylidene ligand is stable and only undergoes H/D exchange under basic conditions, where the imidazolylidene is essentially unreactive. The high stability of the Ir-C bond in aqueous solution over a broad pH range was exploited in catalytic water oxidation and silane oxidation. The catalytic hydrosilylation of ketones proceeds with turnover frequencies as high as 6,000 h(-1) with both the imidazolylidene and the triazolylidene system, whereas water oxidation is enhanced by the stronger donor properties of the imidazol-4-ylidene ligands and is more than three times faster than with the triazolylidene analogue. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Concentric catalytic combustor

    Science.gov (United States)

    Bruck, Gerald J [Oviedo, FL; Laster, Walter R [Oviedo, FL

    2009-03-24

    A catalytic combustor (28) includes a tubular pressure boundary element (90) having a longitudinal flow axis (e.g., 56) separating a first portion (94) of a first fluid flow (e.g., 24) from a second portion (95) of the first fluid flow. The pressure boundary element includes a wall (96) having a plurality of separate longitudinally oriented flow paths (98) annularly disposed within the wall and conducting respective portions (100, 101) of a second fluid flow (e.g., 26) therethrough. A catalytic material (32) is disposed on a surface (e.g., 102, 103) of the pressure boundary element exposed to at least one of the first and second portions of the first fluid flow.

  4. Catalytic membrane in reduction of aqueous nitrates: operational principles and catalytic performance

    NARCIS (Netherlands)

    Ilinitch, O.M.; Cuperus, F.P.; Nosova, L.V.; Gribov, E.N.

    2000-01-01

    The catalytic membrane with palladium-copper active component supported over the macroporous ceramic membrane, and a series of γ-Al 2O 3 supported Pd-Cu catalysts were prepared and investigated. In reduction of nitrate ions by hydrogen in water at ambient temperature, pronounced internal diffusion

  5. A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater.

    Science.gov (United States)

    Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza

    2016-04-01

    A simple and sensitive flow injection chemiluminescence (CL) method in which CdS quantum dots (QDs) enhanced the CL intensity of a KMnO4-formaldehyde (HCHO) reaction was offered for the determination of HCHO. This CL system was based on the catalytic activity of CdS QDs and their participation in the CL resonance energy transfer (CRET) phenomenon. A possible mechanism for the supplied CL system was proposed using the kinetic curves of the CL systems and the spectra of CL, photoluminescence (PL) and ultraviolet-visible (UV-Vis). The emanated CL intensity of the KMnO4-CdS QDs system was amplified in the presence of a trace level of HCHO. Based on this enhancement effect, a simple and sensitive flow injection CL method was suggested for the determination of HCHO concentration in environmental water and wastewater samples. Under selected optimized experimental conditions, the increased CL intensity was proportional to the HCHO concentration in the range of 0.03-4.5 μg L(-1) and 4.5-10.0 μg L(-1). The detection limits (3σ) were 0.0003 μg L(-1) and 1.2 μg L(-1). The relative standard deviations (RSD%) for eleven replicate determinations of 4.0 μg L(-1) HCHO were 2.2%. Furthermore, the feasibility of the developed method was investigated via the determination of HCHO concentration in environmental water and wastewater samples.

  6. Did Australopithecus and Homo co-exist

    International Nuclear Information System (INIS)

    Vogel, J.C.

    1984-01-01

    Uranium series isotope dating of the tufas at Taung/Buxton suggests a considerably younger age for the Taung child (Australopithecus africanus) than has hitherto been accepted. If this later date is confirmed, it will necessitate a re-think of the evolutionary tree of Man and his ancestors

  7. Catalytic water oxidation by ruthenium(II) quaterpyridine (qpy) complexes: evidence for ruthenium(III) qpy-N,N'''-dioxide as the real catalysts.

    Science.gov (United States)

    Liu, Yingying; Ng, Siu-Mui; Yiu, Shek-Man; Lam, William W Y; Wei, Xi-Guang; Lau, Kai-Chung; Lau, Tai-Chu

    2014-12-22

    Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation-resistant and can stabilize high-oxidation-state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2 ](2+) (qpy=2,2':6',2'':6'',2'''-quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze Ce(IV) -driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy-N,N'''-dioxide (ONNO) complexes [Ru(ONNO)(L)2 ](3+) which are the real catalysts for water oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    KAUST Repository

    Liu, Chao; von Gunten, Urs; Croue, Jean-Philippe

    2012-01-01

    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

  9. Study of the water-gas shift reaction on Mo2C/Mo catalytic coatings for application in microstructured fuel processors

    NARCIS (Netherlands)

    Rebrov, E.V.; Kuznetsov, S.A.; Croon, de M.H.J.M.; Schouten, J.C.

    2007-01-01

    The activity and stability of two types of molybdenum carbide coatings deposited on molybdenum substrates (Mo2C/Mo) were compared in the water-gas shift reaction at 513–631 K. The activity of the Mo2C/Mo coatings obtained by carburization of preoxidized molybdenum substrates in a CH4/H2 mixture at

  10. Aerobic, catalytic oxidation of alcohols in ionic liquids

    Directory of Open Access Journals (Sweden)

    Souza Roberto F. de

    2006-01-01

    Full Text Available An efficient and simple catalytic system based on RuCl3 dissolved in ionic liquids has been developed for the oxidation of alcohols into aldehydes and ketones under mild conditions. A new fluorinated ionic liquid, 1-n-butyl-3-methylimidazolium pentadecafluorooctanoate, was synthesized and demonstrated better performance that the other ionic liquids employed. Moreover this catalytic system utilizes molecular oxygen as an oxidizing agent, producing water as the only by-product.

  11. Catalytic biomass pyrolysis process

    Science.gov (United States)

    Dayton, David C.; Gupta, Raghubir P.; Turk, Brian S.; Kataria, Atish; Shen, Jian-Ping

    2018-04-17

    Described herein are processes for converting a biomass starting material (such as lignocellulosic materials) into a low oxygen containing, stable liquid intermediate that can be refined to make liquid hydrocarbon fuels. More specifically, the process can be a catalytic biomass pyrolysis process wherein an oxygen removing catalyst is employed in the reactor while the biomass is subjected to pyrolysis conditions. The stream exiting the pyrolysis reactor comprises bio-oil having a low oxygen content, and such stream may be subjected to further steps, such as separation and/or condensation to isolate the bio-oil.

  12. Catalytic reforming methods

    Science.gov (United States)

    Tadd, Andrew R; Schwank, Johannes

    2013-05-14

    A catalytic reforming method is disclosed herein. The method includes sequentially supplying a plurality of feedstocks of variable compositions to a reformer. The method further includes adding a respective predetermined co-reactant to each of the plurality of feedstocks to obtain a substantially constant output from the reformer for the plurality of feedstocks. The respective predetermined co-reactant is based on a C/H/O atomic composition for a respective one of the plurality of feedstocks and a predetermined C/H/O atomic composition for the substantially constant output.

  13. Polymer supported gold nanoparticles: Synthesis and characterization of functionalized polystyrene-supported gold nanoparticles and their application in catalytic oxidation of alcohols in water

    Science.gov (United States)

    Kaboudin, Babak; Khanmohammadi, Hamid; Kazemi, Foad

    2017-12-01

    Sulfonated polystyrene microsphere were functionalized using ethylene diamine to introduce amine groups to the polymer chains. The amine functionalized polymers were used as a support for gold nanoparticles. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, EDS, CHN and atomic absorption spectroscopy. The polymer supported gold nanoparticles was found to be an efficient catalyst for the oxidation of alcohols in water.

  14. Direct determination of tellurium and its redox speciation at the low nanogram level in natural waters by catalytic cathodic stripping voltammetry.

    Science.gov (United States)

    Biver, Marc; Quentel, François; Filella, Montserrat

    2015-11-01

    Tellurium is one of the elements recently identified as technologically critical and is becoming a new emergent contaminant. No reliable method exists for its determination in environmental samples such as natural waters. This gap is filled by the method described here; it allows the rapid detection of trace concentrations of Te(IV) and Te(VI) in surface waters by differential pulse cathodic stripping voltammetry. It is based on the proton reduction catalysed by the absorption of Te(IV) on the mercury electrode. Under our conditions (0.1 mol L(-1) HCl) a detection limit of about 5 ng L(-1) for a deposition time of 300 s is achieved. Organic matter does not represent a problem at low concentrations; higher concentrations are eliminated by adsorptive purification. Tellurium occurs primarily as Te(IV) and Te(VI) in natural waters. Thus, determining total Te requires the reduction of Te(VI) that it is not electroactive. A number of reduction procedures have been carefully evaluated and a method based on the addition of TiCl3 to the acidified samples has been proven to reduce Te(VI) at the trace level to Te(IV) reliably and quantitatively. Therefore, the procedure described allows the direct determination of total Te and its redox speciation. It is flexible, reliable and cost effective compared to any possible alternative method based on the common preconcentration-ICPMS approach. It is readily implementable as a routine method and can be deployed in the field with relative ease. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Wait-and-see policy versus cholecystectomy after endoscopic sphincterotomy for bile-duct stones in high-risk patients with co-existing gallbladder stones: a prospective randomised trial.

    Science.gov (United States)

    Zargar, Showkat A; Mushtaq, Mosin; Beg, Mashkoor A; Javaid, Gul; Khan, Bashir A; Hassan, Rayhana; Kasana, Reyaz A; Tabassum, Sameena

    2014-03-01

    Endoscopic sphincterotomy (ES) is one of the most important advances in the treatment of common bile duct (CBD) stones. However, the use of ES to remove CBD stones in high-risk patients without cholecystectomy is still debatable. The aim of this study was to compare the efficacy of a wait-and-see policy versus cholecystectomy after ES for CBD stones in high-risk patients with co-existing cholelithiasis. A total of 162 patients after undergoing ES with the clearance of CBD stones were randomised after informed consent to cholecystectomy or conservative management of their gallbladder stones. The results indicated that cholecystectomy after ES for CBD stones significantly reduced the biliary complications in high-risk patients. Every patient who has both CBD stones and gallstones with significant co-morbid illnesses, after clearance of CBD stones by ES, should undergo early cholecystectomy. Copyright © 2014 Arab Journal of Gastroenterology. Published by Elsevier Ltd. All rights reserved.

  16. Nuclear resonant scattering evidence of the phase co-existence during structural phase transformation in [Fe(H{sub 2}O){sub 6}](ClO{sub 4}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Vanko, Gy. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Research Group for Nuclear Techniques in Structural Chemistry, Hungarian Academy of Sciences at Eoetvoes L. University, P.O. Box 32, H-1518 Budapest (Hungary); Bottyan, L. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Deak, L. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Fetzer, Cs. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Juhasz, G. [Department of Nuclear Chemistry, Eoetvoes L. University, P.O. Box 32, H-1518 Budapest (Hungary); Leupold, O. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Institut fuer Experimentalphysik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany); Molnar, B. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Rueter, H.D. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Nagy, D.L. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)]. E-mail: nagy@rmki.kfki.hu

    2005-09-29

    The phase transition associated with orbital-ground-state inversion of high-spin Fe{sup 2+} in [Fe(H{sub 2}O){sub 6}](ClO{sub 4}){sub 2} was studied with nuclear resonant forward scattering of synchrotron radiation (SR). The sudden change in the {sup 57}Fe{sup 2+} quadrupole interaction results in a change of the quantum-beat frequencies. Quantum-beat patterns taken at the phase transition of [Fe(H{sub 2}O){sub 6}](ClO{sub 4}){sub 2} are in accordance with mainly coherent rather than with incoherent sums of the scattering amplitudes of the high- and low-quadrupole-interaction phases, a fact supporting the real co-existence of the two phases.

  17. Light-induced catalytic transformation of ofloxacin by solar Fenton in various water matrices at a pilot plant: mineralization and characterization of major intermediate products.

    Science.gov (United States)

    Michael, I; Hapeshi, E; Aceña, J; Perez, S; Petrović, M; Zapata, A; Barceló, D; Malato, S; Fatta-Kassinos, D

    2013-09-01

    This work investigated the application of a solar driven advanced oxidation process (solar Fenton), for the degradation of the antibiotic ofloxacin (OFX) in various environmental matrices at a pilot-scale. All experiments were carried out in a compound parabolic collector pilot plant in the presence of doses of H2O2 (2.5 mg L(-1)) and at an initial Fe(2+) concentration of 2 mg L(-1). The water matrices used for the solar Fenton experiments were: demineralized water (DW), simulated natural freshwater (SW), simulated effluent from municipal wastewater treatment plant (SWW) and pre-treated real effluent from municipal wastewater treatment plant (RE) to which OFX had been spiked at 10 mg L(-1). Dissolved organic carbon removal was found to be dependent on the chemical composition of the water matrix. OFX mineralization was higher in DW (78.1%) than in SW (58.3%) at 12 mg L(-1) of H2O2 consumption, implying the complexation of iron or the scavenging of hydroxyl radicals by the inorganic ions present in SW. On the other hand, the presence of dissolved organic matter (DOM) in SWW and RE, led to lower mineralization per dose of H2O2 compared to DW and SW. The major transformation products (TPs) formed during the solar Fenton treatment of OFX, were elucidated using liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS). The transformation of OFX proceeded through a defluorination reaction, accompanied by some degree of piperazine and quinolone substituent transformation while a hydroxylation mechanism occurred by attack of the hydroxyl radicals generated during the process leading to the formation of TPs in all the water matrices, seven of which were tentatively identified. The results obtained from the toxicity bioassays indicated that the toxicity originates from the DOM present in RE and its oxidation products formed during the photocatalytic treatment and not from the TPs resulted from the oxidation of OFX. Copyright © 2013 The Authors. Published by

  18. 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.

  19. 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.

  20. Possible influence of the Kuramoto length in a photo-catalytic water splitting reaction revealed by Poisson-Nernst-Planck equations involving ionization in a weak electrolyte

    Science.gov (United States)

    Suzuki, Yohichi; Seki, Kazuhiko

    2018-03-01

    We studied ion concentration profiles and the charge density gradient caused by electrode reactions in weak electrolytes by using the Poisson-Nernst-Planck equations without assuming charge neutrality. In weak electrolytes, only a small fraction of molecules is ionized in bulk. Ion concentration profiles depend on not only ion transport but also the ionization of molecules. We considered the ionization of molecules and ion association in weak electrolytes and obtained analytical expressions for ion densities, electrostatic potential profiles, and ion currents. We found the case that the total ion density gradient was given by the Kuramoto length which characterized the distance over which an ion diffuses before association. The charge density gradient is characterized by the Debye length for 1:1 weak electrolytes. We discuss the role of these length scales for efficient water splitting reactions using photo-electrocatalytic electrodes.

  1. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    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 ...

  2. Highly efficient catalytic systems based on Pd-coated microbeads

    Science.gov (United States)

    Lim, Jin Hyun; Cho, Ahyoung; Lee, Seung Hwan; Park, Bumkyo; Kang, Dong Woo; Koo, Chong Min; Yu, Taekyung; Park, Bum Jun

    2018-01-01

    The efficiency of two prototype catalysis systems using palladium (Pd)-coated microparticles was investigated with regard to the recovery and recyclability of the catalytic particles. One such system was the interface-adsorption method, in which polymer particles coated with Pd nanoparticles strongly and irreversibly attach to the oil-water interface. Due to the irreversible adsorption of the catalytic particles to the interface, particle loss was completely prevented while mixing the aqueous solution and while collecting the products. The other system was based on the magnetic field-associated particle recovery method. The use of polymeric microparticles containing Pd nanoparticles and magnetite nanoparticles accelerated the sedimentation of the particles in the aqueous phase by applying a strong magnetic field, consequently suppressing drainage of the particles from the reactor along the product stream. Upon multiple runs of the catalytic reactions, it was found that conversion does not change significantly, demonstrating the excellent recyclability and performance efficiency in the catalytic processes.

  3. 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.

  4. Photo-catalytic degradation of an oil-water emulsion using the photo-fenton treatment process: effects and statistical optimization.

    Science.gov (United States)

    Tony, Maha A; Purcell, P J; Zhao, Y Q; Tayeb, A M; El-Sherbiny, M F

    2009-02-01

    The application of advanced oxidation processes (AOPs) to the treatment of an effluent contaminated with hydrocarbon oils was investigated. The AOPs conducted were Fe2+/H2O2 (Fenton's reagent), Fe2+/H2O2/UV (Photo-Fenton's reagent) and UV-photolysis. These technologies utilize the very strong oxidizing power of hydroxyl radicals to oxidize organic compounds to harmless end products such as CO2 and H2O. A synthetic wastewater generated by emulsifying diesel oil and water was used. This wastewater might simulate, for example, a waste resulting from a hydrocarbon oil spill, onto which detergent was sprayed. The experiments utilising the Photo-Fenton treatment method with an artificial UV source, coupled with Fenton's reagent, suggest that the hydrocarbon oil is readily degradable, but that the emulsifying agent is much more resistant to degradation. The results showed that the COD (chemical oxygen demand) removal rate was affected by the Photo-Fenton parameters (Fe2+, H2O2 concentrations and the initial pH) of the aqueous solution. In addition, the applicability of the treatment method to a 'real' wastewater contaminated with hydrocarbon oil is demonstrated. The 'real' wastewater was sourced at a nearby car-wash facility located at a petroleum filling station and the experimental results demonstrate the effectiveness of the treatment method in this case. A statistical analysis of the experimental data using the Statistical Analysis System (SAS) and the response surface methodology (RSM) based on the experimental design was applied to optimize the Photo-Fenton parameters (concentrations of Fe2+, H2O2 and initial pH) and to maximize the COD removal rate (more than 70%).

  5. 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

  6. Electrochemical catalytic treatment of phenol wastewater

    International Nuclear Information System (INIS)

    Ma Hongzhu; Zhang Xinhai; Ma Qingliang; Wang Bo

    2009-01-01

    The slurry bed catalytic treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. In this paper, the electrochemical oxidation of phenol in synthetic wastewater catalyzed by ferric sulfate and potassium permanganate adsorbed onto active bentonite in slurry bed electrolytic reactor with graphite electrode has been investigated. In order to determine the optimum operating condition, the orthogonal experiments were devised and the results revealed that the system of ferric sulfate, potassium permanganate and active bentonite showed a high catalytic efficiency on the process of electrochemical oxidation phenol in initial pH 5. When the initial concentration of phenol was 0.52 g/L (the initial COD 1214 mg/L), up to 99% chemical oxygen demand (COD) removal was obtained in 40 min. According to the experimental results, a possible mechanism of catalytic degradation of phenol was proposed. Environmental estimation was also done and the results showed that the treated wastewater have little impact on plant growth and could totally be applied to irrigation.

  7. 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.

  8. Electrochemical catalytic treatment of phenol wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Ma Hongzhu, E-mail: hzmachem@snnu.edu.cn [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China); Zhang Xinhai [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China); Ma Qingliang [Department of Applied Physics, College of Sciences, Taiyuan University of Technology, 030024 Taiyuan (China); Wang Bo [Institute of Energy Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China)

    2009-06-15

    The slurry bed catalytic treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. In this paper, the electrochemical oxidation of phenol in synthetic wastewater catalyzed by ferric sulfate and potassium permanganate adsorbed onto active bentonite in slurry bed electrolytic reactor with graphite electrode has been investigated. In order to determine the optimum operating condition, the orthogonal experiments were devised and the results revealed that the system of ferric sulfate, potassium permanganate and active bentonite showed a high catalytic efficiency on the process of electrochemical oxidation phenol in initial pH 5. When the initial concentration of phenol was 0.52 g/L (the initial COD 1214 mg/L), up to 99% chemical oxygen demand (COD) removal was obtained in 40 min. According to the experimental results, a possible mechanism of catalytic degradation of phenol was proposed. Environmental estimation was also done and the results showed that the treated wastewater have little impact on plant growth and could totally be applied to irrigation.

  9. 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.)

  10. 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)

  11. 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.

  12. 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; Moon, Juhyuk; Oh, Sang-Gyun; Clark, Simon M.; Monteiro, Paulo J.M.

    2012-01-01

    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.

  13. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    126, No. 2, March 2014, pp. 341–351. c Indian Academy of Sciences. ... enhancement was realized by catalyst design, appropriate choice of reactor, better injection and .... Gas–liquid and liquid–solid transport processes in catalytic reactors.5.

  14. The tritium labeling of Butibufen by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    Santamaria, J.; Rebollo, D.

    1986-01-01

    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

  15. Catalytic Synthesis of Ethyl Ester From Some Common Oils ...

    African Journals Online (AJOL)

    Catalytic conversion of ethanol to fatty acid ethyl esters (FAEE) was carried out by homogeneous and heterogeneous transesterification of melon seed, shea butter and neem seed oils using NaOH, KOH and 5wt%CaO/Al2O3 catalyst systems respectively. Oil content of the seeds from n-hexane or hot water extract ranged ...

  16. Catalytic bioreactors and methods of using same

    Science.gov (United States)

    Worden, Robert Mark; Liu, Yangmu Chloe

    2017-07-25

    Various embodiments provide a bioreactor for producing a bioproduct comprising one or more catalytically active zones located in a housing and adapted to keep two incompatible gaseous reactants separated when in a gas phase, wherein each of the one or more catalytically active zones may comprise a catalytic component retainer and a catalytic component retained within and/or thereon. Each of the catalytically active zones may additionally or alternatively comprise a liquid medium located on either side of the catalytic component retainer. Catalytic component may include a microbial cell culture located within and/or on the catalytic component retainer, a suspended catalytic component suspended in the liquid medium, or a combination thereof. Methods of using various embodiments of the bioreactor to produce a bioproduct, such as isobutanol, are also provided.

  17. 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

  18. Low and medium heating value coal gas catalytic combustor characterization

    Science.gov (United States)

    Schwab, J. A.

    1982-01-01

    Catalytic combustion with both low and medium heating value coal gases obtained from an operating gasifier was demonstrated. A practical operating range for efficient operation was determined, and also to identify potential problem areas were identified for consideration during stationary gas turbine engine design. The test rig consists of fuel injectors, a fuel-air premixing section, a catalytic reactor with thermocouple instrumentation and a single point, water cooled sample probe. The test rig included inlet and outlet transition pieces and was designed for installation into an existing test loop.

  19. Hydrophilic Pt nanoflowers: synthesis, crystallographic analysis and catalytic performance.

    Science.gov (United States)

    Mourdikoudis, Stefanos; Altantzis, Thomas; Liz-Marzán, Luis M; Bals, Sara; Pastoriza-Santos, Isabel; Pérez-Juste, Jorge

    2016-05-21

    Water-soluble Pt nanoflowers (NFs) were prepared by diethylene glycol-mediated reduction of Pt acetylacetonate (Pt(acac) 2 ) in the presence of polyethylenimine. Advanced electron microscopy analysis showed that the NFs consist of multiple branches with a truncated cubic morphology and different crystallographic orientations. We demonstrate that the nature of the solvent strongly influences the resulting morphology. The catalytic performance of the Pt NFs in 4-nitrophenol reduction was found to be superior to that of other nanoparticle-based catalysts. Additionally, the Pt NFs display good catalytic reusability with no loss of activity after five consecutive cycles.

  20. 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....

  1. Co-existence of Rhizobia and Diverse Non-rhizobial Bacteria in the Rhizosphere and Nodules of Dalbergia odorifera Seedlings Inoculated with Bradyrhizobium elkanii, Rhizobium multihospitium–Like and Burkholderia pyrrocinia–Like Strains

    Directory of Open Access Journals (Sweden)

    Junkun Lu

    2017-11-01

    Full Text Available Rhizobia induce root nodules and fix atmospheric N2 for most legume species in exchange for carbon. However, the diverse endophytic non-rhizobial bacteria in legume nodules that co-exist with rhizobia are often ignored because they are difficult to cultivate using routine cultivation approaches. To enhance our understanding of the incidence and diversity of legume–bacteria associations, a high-throughput sequencing analysis of bacterial 16S rRNA genes was used to examine the bacterial community in the rhizospheres and root nodules of Dalbergia odorifera seedlings that were uninoculated or inoculated with Bradyrhizobium elkanii H255, Rhizobium multihospitium–like HT221, or Burkholderia pyrrocinia–like H022238, in two growth media (nitrogen [N]-supplied soil or N-omitted potting mix. Seedlings inoculated with Bradyrhizobium had significantly more nodules than seedlings in the other inoculation conditions, regardless of growth media. Using the 15N natural abundance method, it was shown that the inoculated plants had significantly higher N2 fixation efficiency (48–57% and specific nodule activity [269–313 μg N mg−1 of dry weight (dwt nodule] compared to the uninoculated plants (203 μg N mg−1 dwt nodule. The 16S rRNA gene analysis showed that there was generally a higher bacterial diversity in the rhizosphere than in the nodules in the corresponding condition. Both rhizobial inoculation and media status significantly altered the bacterial communities in the rhizospheres and nodules (P < 0.05, with the exception of the inoculated soil rhizospheres. Regarding non-rhizobial bacteria, three genera, i.e., Lactococcus, Bacillus, and Pseudomonas, were consistently enriched in the rhizosphere and Bradyrhizobium, Chloroplast norank (which belongs to Cyanobacteria, and Lactococcus were commonly found in the nodules. In contrast, common rhizobial genera (including Rhizobium, Mesorhizobium, and Burkholderia were only present in the nodules at low

  2. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    Tanabe, K.; Iizuka, T.

    1983-04-01

    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) [pt

  3. Catalytic Decoupling of Quantum Information

    DEFF Research Database (Denmark)

    Majenz, Christian; Berta, Mario; Dupuis, Frédéric

    2017-01-01

    The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... and quantum state merging, and leads to a resource theory of decoupling....

  4. Synthesis, spectroscopic characterization and catalytic oxidation ...

    Indian Academy of Sciences (India)

    were characterized by infrared, electronic, electron paramagnetic resonance ... The catalytic oxidation property of ruthenium(III) complexes were also ... cies at room temperature. ..... aldehyde part of Schiff base ligands, catalytic activ- ity of new ...

  5. Study of catalytic phenomena in radiation chemistry

    International Nuclear Information System (INIS)

    Dran, J.C.

    1965-01-01

    Two phenomena have been studied: the action of γ rays from radio-cobalt on the adsorption and catalytic properties of ZnO and NiO in. relationship with the heterogeneous oxidation of CO, and the homogeneous catalysis by OsO 4 of the oxidation of various aqueous phase solutes by the same radiation. The prior irradiation of ZnO and of NiO does not modify their catalytic activity but generally increases the adsorption energy of -the gases CO and O 2 . The influence of the radiations appears to be connected with the presence of traces of water on ZnO and of an excess of oxygen on NiO. Osmium tetroxide which is not degraded by irradiation in acid solution, accelerates the radiolytic oxidation of certain compounds (Te IV , Pt 11 , As 111 ) in the presence of oxygen, as a result of its sensitizing effect on the oxidation by H 2 O 2 . In the case of phosphites on the other hand, OsO 4 has a protecting action under certain conditions of acidity and may suppress entirely the chain reaction which characterizes the oxidation of this solute byγ rays. A general mechanism is proposed for these phenomena. The rate constant for the OsO 4 + HO 2 reaction is calculated to be 5.7 x 10 5 l.mol -1 . sec -1 . (author) [fr

  6. Catalytic hydrodeoxygenation of dibenzofuran

    Energy Technology Data Exchange (ETDEWEB)

    La Vopa, V.; Satterfield, C.N.

    The hydrodeoxygenation of dibenzofuran (DBF) on a sulfided NiMo/Al/sub 2/O/sub 3/ catalyst was studied at 350-390 C and 7.0 MPa. The major products isolated were single-ring hydrocarbons, cyclohexane predominating; the remainder were double-ring hydrocarbons, cyclohexylbenzene predominating. No oxygen-containing species other than water were isolated in any significant amount. The initial reactions in the hydrodeoxygenation of DBF are rate-limiting. The non-sulfided (oxide) catalyst is much less active, and double-ring products predominate over single-ring products. From studies of possible intermediates it appears that on a sulfided catalyst two pathways operate in parallel for the hydrodeoxygenation of dibenzofuran: (1) hydrogenation of DBF to hexahydro DBF, which reacts via 2-cyclohexylphenol to form signle-ring hydrocarbons; (2) direct hydrogenolysis via 2-phenylphenol, without prior ring hydrogenation, to form biphenyl and cyclohexylbenzene (a minor route). On this catalyst the overall reaction is first order with respect to hydrogen and to DBF and exhibits an apparent activation energy of 67 kJ/mol. 26 refs., 16 figs., 3 tabs.

  7. Co-existence of COPD and bronchiectasis: a risk factor for a high ratio of main pulmonary artery to aorta diameter (PA:A from computed tomography in COPD patients

    Directory of Open Access Journals (Sweden)

    Dou S

    2018-02-01

    Full Text Available Shuang Dou,1 Chunyan Zheng,1 Xiuli Ji,2 Wei Wang,1 Mengshuang Xie,1 Liwei Cui,1 Wei Xiao1 1Department of Pulmonary Medicine, Qilu Hospital, Shandong University, Jinan, People’s Republic of China; 2Department of Pulmonary Disease, Jinan Traditional Chinese Medicine Hospital, Jinan, People’s Republic of China Background: Pulmonary vascular disease, especially pulmonary hypertension, is an important complication of COPD. Bronchiectasis is considered not only a comorbidity of COPD, but also a risk factor for vascular diseases. The main pulmonary artery to aorta diameter ratio (PA:A ratio has been found to be a reliable indicator of pulmonary vascular disease. It is hypothesized that the co-existence of COPD and bronchiectasis may be associated with relative pulmonary artery enlargement (PA:A ratio >1.Methods: This retrospective study enrolled COPD patients from 2012 through 2016. Demographic and clinical data were collected. Bhalla score was used to determine the severity of bronchiectasis. Patient characteristics were analyzed in two ways: the high (PA:A >1 and low (PA:A ≤1 ratio groups; and COPD with and without bronchiectasis groups. Logistic regression analysis was used to assess risk factors for high PA:A ratios.Results: In this study, 480 COPD patients were included, of whom 168 had radiographic bronchiectasis. Patients with pulmonary artery enlargement presented with poorer nutrition (albumin, 35.6±5.1 vs 38.3±4.9, P<0.001, lower oxygen partial pressure (74.4±34.5 vs 81.3±25.4, P<0.001, more severe airflow obstruction (FEV1.0, 0.9±0.5 vs 1.1±0.6, P=0.004, and a higher frequency of bronchiectasis (60% vs 28.8%, P<0.001 than patients in the low ratio group. Patients with both COPD and bronchiectasis had higher levels of systemic inflammation (erythrocyte sedimentation rate, P<0.001 and fibrinogen, P=0.006 and PA:A ratios (P<0.001. A higher PA:A ratio was significantly closely correlated with a higher Bhalla score (r=0.412, P<0

  8. 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.

  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 process for tritium exchange reaction

    International Nuclear Information System (INIS)

    Hansoo Lee; Kang, H.S.; Paek, S.W.; Hongsuk Chung; Yang Geun Chung; Sook Kyung Lee

    2001-01-01

    The catalytic activities for a hydrogen isotope exchange were measured through the reaction of a vapor and gas mixture. The catalytic activity showed to be comparable with the published data. Since the gas velocity is relatively low, the deactivation was not found clearly during the 5-hour experiment. Hydrogen isotope transfer experiments were also conducted through the liquid phase catalytic exchange reaction column that consisted of a catalytic bed and a hydrophilic bed. The efficiencies of both the catalytic and hydrophilic beds were higher than 0.9, implying that the column performance was excellent. (author)

  11. 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.

  12. Catalytic processes for cleaner fuels

    International Nuclear Information System (INIS)

    Catani, R.; Marchionna, M.; Rossini, S.

    1999-01-01

    More stringent limitations on vehicle emissions require different measurement: fuel reformulation is one of the most important and is calling for a noticeable impact on refinery assets. Composition rangers of the future fuels have been defined on a time scale. In this scenario the evolution of catalytic technologies becomes a fundamental tool for allowing refinery to reach the fixed-by-law targets. In this paper, the refinery process options to meet each specific requirements of reformulated fuels are surveyed [it

  13. 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.

  14. The tritium labelling of ibuprofen by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    Santamaria, J.; Rebollo, D.V.; Rivera, P.; Estaban, M.

    1986-01-01

    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)

  15. A review of liquid-phase catalytic hydrodechlorination

    OpenAIRE

    Alba Nelly Ardila Arias; Consuelo Montes de Correa

    2007-01-01

    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 sp...

  16. Slow, Wet and Catalytic Pyrolysis of Fowl Manure

    OpenAIRE

    Renzo Carta; Mario Cruccu; Francesco Desogus

    2012-01-01

    This work presents the experimental results obtained at a pilot plant which works with a slow, wet and catalytic pyrolysis process of dry fowl manure. This kind of process mainly consists in the cracking of the organic matrix and in the following reaction of carbon with water, which is either already contained in the organic feed or added, to produce carbon monoxide and hydrogen. Reactions are conducted in a rotating reactor maintained at a temperature of 500°C; the requi...

  17. Catalytic Activity Control via Crossover between Two Different Microstructures

    KAUST Repository

    Zhou, Yuheng

    2017-09-08

    Metal nanocatalysts hold great promise for a wide range of heterogeneous catalytic reactions, while the optimization strategy of catalytic activity is largely restricted by particle size or shape control. Here, we demonstrate that a reversible microstructural control through the crossover between multiply-twinned nanoparticle (MTP) and single crystal (SC) can be readily achieved by solvent post-treatment on gold nanoparticles (AuNPs). Polar solvents (e.g. water, methanol) direct the transformation from MTP to SC accompanied by the disappearance of twinning and stacking faults. A reverse transformation from SC to MTP is achieved in non-polar solvent (e.g. toluene) mixed with thiol ligands. The transformation between two different microstructures is directly observed by in-situ TEM and leads to a drastic modulation of catalytic activity towards the gas-phase selective oxidation of alcohols. There is a quasi-linear relationship between TOFs and MTP concentrations. Based on the combined experimental and theoretical investigations of alcohol chemisorption on these nanocatalysts, we propose that the exposure of {211}-like microfacets associated with twin boundaries and stack faults accounts for the strong chemisorption of alcohol molecules on MTP AuNPs and thus the exceptionally high catalytic activity.

  18. Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged Y zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sciyama, T; Arakawa, T; Matsuda, T; Yamazoe, N; Takita, Y

    1975-01-01

    The catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. The reaction products are nitrogen, nitrous oxide, and water in all cases. Selectivities to N/sub 2/ are 60 to 80% on all the cation exchanged zeolite catalysts exhibiting a relatively minor variation with the cationic species exchanged. The copper (II)-Y catalyst exhibits low temperature activity and has an unusual catalytic activity-temperature profile with a maximum at 120/sup 0/C. The catalytic activity is enhanced considerably when a second cation, especially cobalt (II) or iron (III) is coexchanged together with Cu (II) in Y zeolite.

  19. 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.

  20. 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

  1. Catalytic Organometallic Reactions of Ammonia

    Science.gov (United States)

    Klinkenberg, Jessica L.

    2012-01-01

    Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

  2. Catalytic cracking of hydrocarbon oils

    Energy Technology Data Exchange (ETDEWEB)

    1940-09-12

    A process is described for the vapor phase catalytic cracking of hydrocarbon oils boiling substantially in the gas oil range. The reaction takes place in the presence of a solid catalyst between 700 to 900/sup 0/F under pressure between atmospheric and 400 psi. A gas containing between 20 and 90 mol % of free hydrogen is used. The reaction is allowed to proceed until consumption of the free begins. The reaction is discontinued at that point and the catalyst is regenerated for further use.

  3. 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.

  4. Plasma catalytic process for CO2 methanation

    International Nuclear Information System (INIS)

    Nizio, Magdalena

    2016-01-01

    The limited resources of oil and natural gas, together with an increasing energy demand, forces us to seek more and more efficient and cleaner energy production alternatives. Hydrogen has been recently considered as a promising energy carrier. However, there are several inherent problems to the utilization of H 2 , from its transportation to its distribution. Transformation of the H 2 molecule by fixing into a carbon-containing compound, i.e. CH 4 , will offer the possibility of using the conventional transportation network. Indeed, the Sabatier reaction, which is highly exothermic, involves the reaction of carbon dioxide and hydrogen gas in order to produce methane and water. This process, called methanation, represents a feasible approach contributing to the reduction of the CO 2 emissions in our atmosphere, through a closed carbon cycle involving the valorization of CO 2 , i.e. from capture. However, below a temperature of 250 C, the conversion becomes practically close to 0 %, whereas at higher temperatures, i.e., (≥300 C), the co-existence of secondary reactions favours the formation of CO and H 2 . This is the reason why new catalysts and process conditions are continuously being investigated in order to maximize the methane selectivity at low reaction temperatures at atmospheric pressure. Therefore, by using catalysts combined to Dielectric Barrier Discharge plasmas (DBD), the activation of the methanation reaction can be enhanced and overcome the drawbacks of existing conventional processes. Several Ni-containing catalysts were prepared using various ceria-zirconia oxides as supports, with different Ce/Zr ratios. The results obtained in the adiabatic conditions at low temperatures (ranging between 100-150 C), in the presence of catalysts activated by plasma, are promising. Indeed, the conversion of CO 2 to CH 4 is about 85 % with a selectivity close to 100 %. The same conversion in the absence of the plasma activation of the catalyst is observed at 350 C

  5. Catalytic enantioselective Reformatsky reaction with ketones

    NARCIS (Netherlands)

    Fernandez-Ibanez, M. Angeles; Macia, Beatriz; Minnaard, Adriaan J.; Feringa, Ben L.

    2008-01-01

    Chiral tertiary alcohols were obtained with good yields and enantioselectivities via a catalytic Reformatsky reaction with ketones, including the challenging diaryl ketones, using chiral BINOL derivatives.

  6. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Petrochemical promoters in catalytic cracking

    International Nuclear Information System (INIS)

    Gomez, Maria; Vargas, Clemencia; Lizcano, Javier

    2010-01-01

    This study is based on the current scheme followed by a refinery with available Catalytic Cracking capacity to process new feedstocks such as Straight Run Naphtha and Naphthas from FCC. These feedstocks are of petrochemical interest to produce Ethane, Ethylene, Propylene, i-Butane, Toluene and Xylene. To evaluate the potential of these new streams versus the Cracking-charged Residues, it was performed a detailed chemical analysis on the structural groups in carbons [C1-C12] at the reactor product obtained in pilot plant. A catalyst with and without Propylene Promoter Additive was used. This study analyzes the differences in the chemical composition of the feedstocks, relating them to the yield of each petrochemical product. Straight Run Naphthas with a high content of Naphthenes, and Paraffines n[C5-C12] and i[C7-C12] are selective to the production of i-Butane and Propane, while Naphthas from FCC with a high content of n[C5-C12]Olefins, i-Olefins, and Aromatics are more selective to Propylene, Toluene, and Xylene. Concerning Catalytic Cracking of Naphthas, the Additive has similar selectivity for all the petrochemical products, their yields increase by about one point with 4%wt of Additive, while in cracking of Residues, the Additive increases in three points Propylene yield, corresponding to a selectivity of 50% (?C3= / ?LPG).

  8. 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).

  9. Catalytic converters in the fireplace

    International Nuclear Information System (INIS)

    Kouki, J.

    1995-01-01

    In addition to selecting the appropriate means of heating and using dry fuel, the amount of harmful emissions contained by flue gases produced by fireplaces can be reduced by technical means. One such option is to use an oxidising catalytic converter. Tests at TTS Institute's Heating Studies Experimental Station have focused on two such converters (dense and coarse) mounted in light-weight iron heating stoves. The ability of the dense catalytic converter to oxidise carbon monoxide gases proved to be good. The concentration of carbon monoxide in the flue gases was reduced by as much as 90 %. Measurements conducted by VTT (Technical Research Centre of Finland) showed that the conversion of other gases, e.g. of methane, was good. The exhaust resistance caused by the dense converter was so great as to necessitate the mounting of a fluegas evacuation fan in the chimney for the purpose of creating sufficient draught. When relying on natural draught, the dense converter requires a chimney of at least 7 metres and a by-pass connection while the fire is being lit. In addition, the converter will have to be constructed to be less dense and this will mean that it's capability to oxidise non-combusted gases will be reduced. The coarse converter did not impair the draught but it's oxidising property was insufficient. With the tests over, the converter was not observed to have become blocked up by impurities

  10. 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

  11. Three-Dimensional Structure and Catalytic Mechanism of Cytosine Deaminase

    Energy Technology Data Exchange (ETDEWEB)

    R Hall; A Fedorov; C Xu; E Fedorov; S Almo; F Raushel

    2011-12-31

    Cytosine deaminase (CDA) from E. coli is a member of the amidohydrolase superfamily. The structure of the zinc-activated enzyme was determined in the presence of phosphonocytosine, a mimic of the tetrahedral reaction intermediate. This compound inhibits the deamination of cytosine with a K{sub i} of 52 nM. The zinc- and iron-containing enzymes were characterized to determine the effect of the divalent cations on activation of the hydrolytic water. Fe-CDA loses activity at low pH with a kinetic pKa of 6.0, and Zn-CDA has a kinetic pKa of 7.3. Mutation of Gln-156 decreased the catalytic activity by more than 5 orders of magnitude, supporting its role in substrate binding. Mutation of Glu-217, Asp-313, and His-246 significantly decreased catalytic activity supporting the role of these three residues in activation of the hydrolytic water molecule and facilitation of proton transfer reactions. A library of potential substrates was used to probe the structural determinants responsible for catalytic activity. CDA was able to catalyze the deamination of isocytosine and the hydrolysis of 3-oxauracil. Large inverse solvent isotope effects were obtained on k{sub cat} and k{sub cat}/K{sub m}, consistent with the formation of a low-barrier hydrogen bond during the conversion of cytosine to uracil. A chemical mechanism for substrate deamination by CDA was proposed.

  12. 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.

  13. Catalytic production of metal carbonyls from metal oxides

    Science.gov (United States)

    Sapienza, Richard S.; Slegeir, William A.; Foran, Michael T.

    1984-01-01

    This invention relates to the formation of metal carbonyls from metal oxides and specially the formation of molybdenum carbonyl and iron carbonyl from their respective oxides. Copper is used here in admixed form or used in chemically combined form as copper molybdate. The copper/metal oxide combination or combined copper is utilized with a solvent, such as toluene and subjected to carbon monoxide pressure of 25 atmospheres or greater at about 150.degree.-260.degree. C. The reducing metal copper is employed in catalytic concentrations or combined concentrations as CuMoO.sub.4 and both hydrogen and water present serve as promoters. It has been found that the yields by this process have been salutary and that additionally the catalytic metal may be reused in the process to good effect.

  14. Heterogeneous Photo catalytic Degradation of Hazardous Waste in Aqueous Suspension

    International Nuclear Information System (INIS)

    Sadek, S.A.; Ebraheem, S.; Friesen, K.J.

    1999-01-01

    The photo catalytic degradation of hazardous waste like chlorinated paraffin compound (1,12-Dichlorodoecane Ded) was investigated in different aquatic media using GC-MSD. The direct photolysis of Ded in HPLC water was considered to be negligible (k = 0.0020+-0.0007h - 1 ) . An acceleration of the photodegradation rate was occurred in presence of different TiO 2 catalyst systems. Molecular oxygen was found to play a vital role in the degradation process. Anatase TiO 2 was proved to be the most efficient one (k=0.7670+-0.0876h -1 ), while the rate constant of the rutile TiO 2 was calculated to be 0.2780+-0.0342h -1 . Improvement of photo catalytic efficiency of rutile TiO 2 was achieved by addition of Fe +2 giving a rate constant =0.6710+-0.0786h -1

  15. Heterogeneous catalytic degradation of polyacrylamide solution | Hu ...

    African Journals Online (AJOL)

    Modified with trace metal elements, the catalytic activity of Fe2O3/Al2O3 could be changed greatly. Among various trace metal elements, Fe2O3/Al2O3 catalysts modified with Co and Cu showed great increase on catalytic activity. International Journal of Engineering, Science and Technology, Vol. 2, No. 7, 2010, pp. 110- ...

  16. 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.

  17. Method of fabricating a catalytic structure

    Science.gov (United States)

    Rollins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2009-09-22

    A precursor to a catalytic structure comprising zinc oxide and copper oxide. The zinc oxide has a sheet-like morphology or a spherical morphology and the copper oxide comprises particles of copper oxide. The copper oxide is reduced to copper, producing the catalytic structure. The catalytic structure is fabricated by a hydrothermal process. A reaction mixture comprising a zinc salt, a copper salt, a hydroxyl ion source, and a structure-directing agent is formed. The reaction mixture is heated under confined volume conditions to produce the precursor. The copper oxide in the precursor is reduced to copper. A method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure.

  18. Catalytic hydrogenation of carbon monoxide

    International Nuclear Information System (INIS)

    Wayland, B.B.

    1993-12-01

    Focus of this project is on developing new approaches for hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. The strategies to accomplish CO reduction are based on favorable thermodynamics manifested by rhodium macrocycles for producing a series of intermediates implicated in the catalytic hydrogenation of CO. Metalloformyl complexes from reactions of H 2 and CO, and CO reductive coupling to form metallo α-diketone species provide alternate routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. 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. Non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics are promising candidates for future development

  19. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

    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.)

  20. Non-catalytic recuperative reformer

    Science.gov (United States)

    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.

  1. Studies of Catalytic Model Systems

    DEFF Research Database (Denmark)

    Holse, Christian

    The overall topic of this thesis is within the field of catalysis, were model systems of different complexity have been studied utilizing a multipurpose Ultra High Vacuum chamber (UHV). The thesis falls in two different parts. First a simple model system in the form of a ruthenium single crystal...... of the Cu/ZnO nanoparticles is highly relevant to industrial methanol synthesis for which the direct interaction of Cu and ZnO nanocrystals synergistically boost the catalytic activity. The dynamical behavior of the nanoparticles under reducing and oxidizing environments were studied by means of ex situ X......-ray Photoelectron Electron Spectroscopy (XPS) and in situ Transmission Electron Microscopy (TEM). The surface composition of the nanoparticles changes reversibly as the nanoparticles exposed to cycles of high-pressure oxidation and reduction (200 mbar). Furthermore, the presence of metallic Zn is observed by XPS...

  2. 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.)

  3. The evolution of catalytic function

    Science.gov (United States)

    Maurel, Marie-Christine; Ricard, Jacques

    2006-03-01

    It is very likely that the main driving force of enzyme evolution is the requirement to improve catalytic and regulatory efficiency which results from the intrinsic performance as well as from the spatial and functional organization of enzymes in living cells. Kinetic co-operativity may occur in simple monomeric proteins if they display “slow” conformational transitions, at the cost of catalytic efficiency. Oligomeric enzymes on the other hand can be both efficient and co-operative. We speculate that the main reason for the emergence of co-operative oligomeric enzymes is the need for catalysts that are both cooperative and efficient. As it is not useful for an enzyme to respond to a change of substrate concentration in a complex kinetic way, the emergence of symmetry has its probable origin in a requirement for “functional simplicity”. In a living cell, enzyme are associated with other macromolecules and membranes. The fine tuning of their activity may also be reached through mutations of the microenvironment. Our hypothesis is that these mutations are related to the vectorial transport of molecules, to achieve the hysteresis loops of enzyme reactions generated by the coupling of reaction and diffusion, through the co-operativity brought about by electric interactions between a charged substrate and a membrane, and last but not least, through oscillations. As the physical origins of these effects are very simple and do not require complex molecular devices, it is very likely that the functional advantage generated by the spatial and functional organization of enzyme molecules within the cell have appeared in prebiotic catalysis or very early during the primeval stages of biological evolution. We shall began this paper by presenting the nature of the probable earliest catalysts in the RNA world.

  4. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Science.gov (United States)

    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.

  5. Catalytic glycerol steam reforming for hydrogen production

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 H 2 . In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al 2 O 3 . The catalyst was prepared by wet impregnation method and characterized through different methods: N 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 2 , CH 4 , CO, CO 2 . The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H 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%

  6. 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%.

  7. Catalytic combustion of gasified waste - Experimental part. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jaeraas, Sven; Kusar, Henrik [Royal Institute of Technology, Stockholm (Sweden). Chemical Engineering and Technology

    2003-08-01

    This final report covers the work that has been performed within the project P 10547-2, 'Catalytic combustion of gasified waste - system analysis ORWARE'. This project is part of the research programme 'Energy from Waste' financed by the Swedish National Energy Administration. The project has been carried out at the division of Industrial Ecology and at the division of Chemical Technology at Royal Inst. of Technology. The aim of the project has been to study the potentials for catalytic combustion of gasified waste. The supposed end user of the technique is a smaller community in Sweden with 15,000-20,000 inhabitants. The project contains of two sub projects: an experimental part carried out at Chemical Technology and a system analysis carried out at Industrial Ecology. This report covers the experimental part of the project carried out at Chemical Technology. The aim for the experimental part has been to develop and test catalysts with long life-time and a high performance, to reduce the thermal-NO{sub x} below 5 ppm and to significantly reduce NO{sub x} formed from fuel-bound nitrogen. Different experimental studies have been carried out within the project: a set-up of catalytic materials have been tested over a synthetic mixture of the gasified waste, the influence of sulfur present in the gas stream, NO{sub x} formation from fuel bound nitrogen, kinetic studies of CO and H{sub 2} with and without the presence of water and the effects of adding a co-metal to palladium catalysts Furthermore a novel annular reactor design has been used to carry out experiments for kinetic measurements. Real gasification tests of waste pellets directly coupled to catalytic combustion have successfully been performed. The results obtained from the experiments, both the catalytic combustion and from the gasification, have been possible to use in the system analysis. The aim of the system analysis of catalytic combustion of gasified waste takes into consideration

  8. Catalytic modification of cellulose and hemicellulose - Sugarefine

    Energy Technology Data Exchange (ETDEWEB)

    Repo, T. [Helsinki Univ. (Finland),Laboratory of Inorganic Chemistry], email: timo.repo@helsinki.fi

    2012-07-01

    The main goal of the project is to develop catalytic methods for the modification of lignocellulose-based saccharides in the biorefineries. The products of these reactions could be used for example as biofuel components, raw materials for the chemical industry, solvents and precursors for biopolymers. The catalyst development aims at creating efficient, selective and green catalytic methods for profitable use in biorefineries. The project is divided in three work packages: In WP1 (Catalytic dehydration of cellulose) the aim is at developing non-toxic, efficient methods for the catalytic dehydration of cellulose the target molecule being here 5-hydroxymethylfurfural (5-HMF). 5-HMF is an interesting platform chemical for the production of fuel additives, solvents and polymers. In WP2 (Catalytic reduction), the objective of the catalytic reduction studies is to produce commercially interesting monofunctional chemicals, such as 1-butanol or 2-methyltetrahydrofuran (2-MeTHF). In WP3 (Catalytic oxidation), the research focuses on developing a green and efficient oxidation method for producing acids. Whereas acetic and formic acids are bulk chemicals, diacids such as glucaric and xylaric acids are valuable specialty chemicals for detergent, polymer and food production.

  9. Pd-catalytic in situ generation of H2O2 from H2 and O2 produced by water electrolysis for the efficient electro-fenton degradation of rhodamine B.

    Science.gov (United States)

    Yuan, Songhu; Fan, Ye; Zhang, Yucheng; Tong, Man; Liao, Peng

    2011-10-01

    A novel electro-Fenton process was developed for wastewater treatment using a modified divided electrolytic system in which H2O2 was generated in situ from electro-generated H2 and O2 in the presence of Pd/C catalyst. Appropriate pH conditions were obtained by the excessive H+ produced at the anode. The performance of the novel process was assessed by Rhodamine B (RhB) degradation in an aqueous solution. Experimental results showed that the accumulation of H2O2 occurred when the pH decreased and time elapsed. The maximum concentration of H2O2 reached 53.1 mg/L within 120 min at pH 2 and a current of 100 mA. Upon the formation of the Fenton reagent by the addition of Fe2+, RhB degraded completely within 30 min at pH 2 with a pseudo first order rate constant of 0.109 ± 0.009 min(-1). An insignificant decline in H2O2 generation and RhB degradation was found after six repetitions. RhB degradation was achieved by the chemisorption of H2O2 on the Pd/C surface, which subsequently decomposed into •OH upon catalysis by Pd0 and Fe2+. The catalytic decomposition of H2O2 to •OH by Fe2+ was more powerful than that by Pd0, which was responsible for the high efficiency of this novel electro-Fenton process.

  10. Water

    Science.gov (United States)

    ... drink and water in food (like fruits and vegetables). 6. Of all the earth’s water, how much is ocean or seas? 97 percent of the earth’s water is ocean or seas. 7. How much of the world’s water is frozen? Of all the water on earth, about 2 percent is frozen. 8. How much ...

  11. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    International Nuclear Information System (INIS)

    Lu, Yi

    2003-01-01

    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

  12. Modelling of procecces in catalytic recombiners

    International Nuclear Information System (INIS)

    Boehm, J.

    2007-01-01

    In order to achieve a high degree of safety in nuclear power plants and prevent possible accident scenarios, their consequences are calculated and analysed with numeric codes. One of the most important part of nuclear safety research of hazardous incidents are development and validation of these numeric models, which are implemented into accident codes. The severe hydrogen release during a core meltdown is one of the considered scenario of performed accident analyses. One of the most important measure for the elimination of the hydrogen is catalytic recombiners. Converting the hydrogen with the atmospheric oxygen to water vapor in an exothermic reaction will prevent possible detonation of the hydrogen/air atmosphere. Within the dissertation the recombiner simulation REKO-DIREKT was developed and validated by an extensive experimental database. The performance of recombiners with regard to the conversion of the hydrogen and the temperature development is modelled. The REKO-DIREKT program is unique and has made significant revolution in research of hydrogen safety. For the first time it has been possible to show the performance of the recombiner so great in detail by using REKO-DIREKT. In the future engineers of nuclear power plants will have opportunity to have precise forecasts about the process of the possible accidents with hydrogen release. Also with presence of water vapor or with oxygen depletion which are included in the model. The major discussion of the hydrogen ignition at hot catalyst steel plates can be evaluated in the future with REKO-DIREKT more reliably than the existing used models. (orig.)

  13. Catalytic Wittig and aza-Wittig reactions

    Directory of Open Access Journals (Sweden)

    Zhiqi Lao

    2016-11-01

    Full Text Available This review surveys the literature regarding the development of catalytic versions of the Wittig and aza-Wittig reactions. The first section summarizes how arsenic and tellurium-based catalytic Wittig-type reaction systems were developed first due to the relatively easy reduction of the oxides involved. This is followed by a presentation of the current state of the art regarding phosphine-catalyzed Wittig reactions. The second section covers the field of related catalytic aza-Wittig reactions that are catalyzed by both phosphine oxides and phosphines.

  14. Catalytic models developed through social work

    DEFF Research Database (Denmark)

    Jensen, Mogens

    2015-01-01

    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......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...

  15. Efficient catalytic combustion in integrated micropellistors

    International Nuclear Information System (INIS)

    Bársony, I; Ádám, M; Fürjes, P; Dücső, Cs; Lucklum, R; Hirschfelder, M; Kulinyi, S

    2009-01-01

    This paper analyses two of the key issues of the development of catalytic combustion-type sensors: the selection and production of active catalytic particles on the micropellistor surface as well as the realization of a reliable thermal conduction between heater element and catalytic surface, for the sensing of temperature increase produced by the combustion. The report also demonstrates that chemical sensor product development by a MEMS process is a continuous struggle for elimination of all uncertainties influencing reliability and sensitivity of the final product

  16. 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

  17. Vacuum-insulated catalytic converter

    Science.gov (United States)

    Benson, David K.

    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.

  18. Catalytic hydrotreatment of refinery waste

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The object of the project is to produce liquid hydrocarbons by the catalytic hydroprocessing of solid refinery wastes (hard pitches) in order to improve the profitability of deep conversion processes and reduce the excess production of heavy fuels. The project was mostly carried out on the ASVAHL demonstration platform site, at Solaize, and hard pitches were produced primarily by deasphalting of atmospheric or vacuum distillation residues. The project includes two experimental phases and an economic evaluation study phase. In phase 1, two granular catalysts were used to transform pitch into standard low sulphur fuel oil: a continuously moving bed, with demetallation and conversion catalyst; a fixed bed, with hydrorefining catalyst. In phase 2 of the project, it was proven that a hydrotreatment process using a finely dispersed catalyst in the feedstock, can, under realistic operating conditions, transform with goods yields hard pitch into distillates that can be refined through standard methods. In phase 3 of the project, it was shown that the economics of such processes are tightly linked to the price differential between white and black oil products, which is expected to increase in the future. Furthermore, the evolution of environmental constraints will impel the use of such methods, thus avoiding the coproduction of polluting solid residues.

  19. Water

    International Nuclear Information System (INIS)

    Chovanec, A.; Grath, J.; Kralik, M.; Vogel, W.

    2002-01-01

    An up-date overview of the situation of the Austrian waters is given by analyzing the status of the water quality (groundwater, surface waters) and water protection measures. Maps containing information of nitrate and atrazine in groundwaters (analyses at monitoring stations), nitrate contents and biological water quality of running waters are included. Finally, pollutants (nitrate, orthophosphate, ammonium, nitrite, atrazine etc.) trends in annual mean values and median values for the whole country for the years 1992-1999 are presented in tables. Figs. 5. (nevyjel)

  20. Catalytic pyrolysis of microalgae to high-quality liquid bio-fuels

    International Nuclear Information System (INIS)

    Babich, I.V.; Hulst, M. van der; Lefferts, L.; Moulijn, J.A.; O'Connor, P.; Seshan, K.

    2011-01-01

    The pyrolytic conversion of chlorella algae to liquid fuel precursor in presence of a catalyst (Na 2 CO 3 ) has been studied. Thermal decomposition studies of the algae samples were performed using TGA coupled with MS. Liquid oil samples were collected from pyrolysis experiments in a fixed-bed reactor and characterized for water content and heating value. The oil composition was analyzed by GC-MS. Pretreatment of chlorella with Na 2 CO 3 influences the primary conversion of chlorella by shifting the decomposition temperature to a lower value. In the presence of Na 2 CO 3 , gas yield increased and liquid yield decreased when compared with non-catalytic pyrolysis at the same temperatures. However, pyrolysis oil from catalytic runs carries higher heating value and lower acidity. Lower content of acids in the bio-oil, higher aromatics, combined with higher heating value show promise for production of high-quality bio-oil from algae via catalytic pyrolysis, resulting in energy recovery in bio-oil of 40%. -- Highlights: → The pyrolytic catalytic conversion of chlorella algae to liquid fuel precursor. → Na 2 CO 3 as a catalyst for the primary conversion of chlorella. → Pyrolysis oil from catalytic runs carries higher heating value and lower acidity. → High-quality bio-oil from algae via catalytic pyrolysis with energy recovery in bio-oil of 40%.

  1. Chemistry and engineering of catalytic hydrodesulfurization

    NARCIS (Netherlands)

    Schuit, G.C.A.; Gates, B.C.

    1973-01-01

    A review with 74 refs. on catalytic hydrodesulfurization of pure compds. and petroleum feedstocks, with emphasis on reaction intermediates and structures of Al2O3-supported Ni-W and Co-Mo catalysts. [on SciFinder (R)

  2. The tritium labelling of organic molecules by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    Angoso, M.; Kaiser, F.

    1977-01-01

    The influence of the temperature at 65degC and 120degC on the labelling of three organic molecules with tritium was studied. The compounds were: benzoic acid, diphenyl glioxal and 2,3-tetramethylene-4-phenylthien-7-oxodiacetin. The method employed was the heterogeneous catalytic exchange between tritiaded water and the organic compound. The purification was made by thin-layer chromatography and the concentration, purity and specific activity of the products were determined by counting and ultraviolet techniques. The thermal stability and the radiolitic effects on labelled benzoic acid were also considered. (author) [es

  3. The tritium labelling of organic molecules by heterogeneous catalytic exchange

    International Nuclear Information System (INIS)

    Angoso Marina, M.; Kaiser Ruiz del Olmo, F.

    1977-01-01

    The influence of the temperature at 65 degree centigree and 120 degree centigree on the labelling of three organic molecules with tritium was studied. The compounds were: benzoic acid, de phenyl glyoxal and 2,3-tetramethylene-4-pantothenyl-7-oxo diacetin.The method employed was the heterogeneous catalytic exchange between tritiated water and the organic compound. The purification was made by thin-layer chromatography and the concentration, purity and specific activity of the products were determined by counting and ultraviolet techniques. The thermal stability and the radiolytic effects on labelled benzoic acid were also considered. (Author) 9 refs

  4. A review of liquid-phase catalytic hydrodechlorination

    Directory of Open Access Journals (Sweden)

    Alba Nelly Ardila Arias

    2007-09-01

    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.

  5. Water

    Science.gov (United States)

    ... can be found in some metal water taps, interior water pipes, or pipes connecting a house to ... reduce or eliminate lead. See resources below. 5. Children and pregnant women are especially vulnerable to the ...

  6. Catalytic Aminohalogenation of Alkenes and Alkynes.

    Science.gov (United States)

    Chemler, Sherry R; Bovino, Michael T

    2013-06-07

    Catalytic aminohalogenation methods enable the regio- and stereoselective vicinal difunctionalization of alkynes, allenes and alkenes with amine and halogen moieties. A range of protocols and reaction mechanisms including organometallic, Lewis base, Lewis acid and Brønsted acid catalysis have been disclosed, enabling the regio- and stereoselective synthesis of halogen-functionalized acyclic amines and nitrogen heterocycles. Recent advances including aminofluorination and catalytic enantioselective aminohalogenation reactions are summarized in this review.

  7. Kinetic catalytic studies of scorpion's hemocyanin

    International Nuclear Information System (INIS)

    Queinnec, E.; Vuillaume, M.; Gardes-Albert, M.; Ferradini, C.; Ducancel, F.

    1991-01-01

    Hemocyanins are copper proteins which function as oxygen carriers in the haemolymph of Molluscs and Arthropods. They possess enzymatic properties: peroxidatic and catalatic activities, although they have neither iron nor porphyrin ring at the active site. The kinetics of the catalytic reaction is described. The reaction of superoxide anion with hemocyanin has been studied using pulse radiolysis at pH 9. The catalytic rate constant is 3.5 X 10 7 mol -1 .l.s -1 [fr

  8. 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.

  9. ZVI (Fe0) desalination: catalytic partial desalination of saline aquifers

    Science.gov (United States)

    Antia, David D. J.

    2018-05-01

    Globally, salinization affects between 100 and 1000 billion m3 a-1 of irrigation water. The discovery that zero valent iron (ZVI, Fe0) could be used to desalinate water (using intra-particle catalysis in a diffusion environment) raises the possibility that large-scale in situ desalination of aquifers could be undertaken to support agriculture. ZVI desalination removes NaCl by an adsorption-desorption process in a multi-stage cross-coupled catalytic process. This study considers the potential application of two ZVI desalination catalyst types for in situ aquifer desalination. The feasibility of using ZVI catalysts when placed in situ within an aquifer to produce 100 m3 d-1 of partially desalinated water from a saline aquifer is considered.

  10. 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.

  11. Sheehan fs syndrome co.existing with Graves' disease | Arpaci ...

    African Journals Online (AJOL)

    Sheehanfs syndrome (SS), which is an important cause of hypopituitarism, is common in developing countries. The most common presentation is the absence of lactation and amenorrhea. Hypothyroidism rather than hyperthyroidism is the usual expected phenomenon in SS. Postpartum hyperthyroidism is also common and ...

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

    International Nuclear Information System (INIS)

    Reeves, R.R.; Leatherwood, S.

    1994-01-01

    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

  13. Invasive lobular carcinoma co-existing with benign phylloides tumor

    Directory of Open Access Journals (Sweden)

    S Shrestha

    2014-04-01

    Full Text Available Phylloides tumor constitutes less than 1% of all breast tumors and 2 - 3% of fibroepithelial breast tumors. Several histological parameters should be evaluated, including stromal cellularity, atypia, mitoses, stromal overgrowth, infiltrative borders, and presence or absence of necrosis. Here we report a case of a 60 years- old female who presented with left breast lump. Fine needle aspiration cytology was done which suggested epithelial hyperplasia with fibrocystic changes. Biopsy was performed which showed predominance of stromal hypercellularity with proliferation of spindle cells (no atypia, mitosis and stromal overgrowth were noticed. However, a focus showed proliferation of discohesive tumor cells arranged singly and in single file. A diagnosis of benign phylloides tumor with foci of invasive lobular carcinoma was made. The diagnosis was confirmed with IHC which showed intense 80%positivity for estrogen and progesterone receptor and spindle cells showing positivity for bcl-2. In situ lobular carcinoma component was not observed. DOI: http://dx.doi.org/10.3126/jpn.v4i7.10321   Journal of Pathology of Nepal (2014 Vol. 4, 597-599

  14. 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...

  15. Sonographic assessment of pregnancy co-existing with uterine ...

    African Journals Online (AJOL)

    Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/ahs.v13i2.36 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of ...

  16. Scientific Research & Subsistence: Protocols to Ensure Co-Existence

    Science.gov (United States)

    Nachman, C.; Holman, A.; DeMaster, D.

    2017-12-01

    Commercial, industrial, and research interests in the Arctic are expanding rapidly. Potentials are numerous and exciting, giving rise to the need for guidelines to ensure interactions among waterway users do not conflict. Of particular concern is the potential for adverse impacts to U.S. Arctic coastal communities that rely on living marine resources for nutritional and cultural health, through subsistence hunts from small craft, ice edges, and shore. Recent events raised concerns over research surveys potentially interfering with subsistence hunts in the Bering, Chukchi, and Beaufort Seas. Incidents led to calls by Native Alaskan communities to restrict science activities with a mixed response from the scientific community (i.e., some sympathetic, some defensive). With a common goal of wanting to mitigate this potential interaction, Federal agencies made a commitment in the National Strategy for the Arctic Region to coordinate and consult with Alaska Natives and also to pursue responsible Arctic stewardship, with understanding through scientific research and traditional knowledge. The effort to create a "Standard of Care" for research surveys incorporates years of experience by subsistence hunters working to mitigate impacts of other anthropogenic activities in the region, as well as best practices by many in the research community. The protocols are designed to ensure potential conflicts between the scientific research community and subsistence hunters are avoided and to encourage mutual assistance and collaboration between researchers and hunters. The guidelines focus on enhancing communication between researchers and subsistence hunters before, during, and after research occurs. The best management practices outlined in the Standard of Care assist those overseeing and funding scientific research in making decisions about how best to accomplish the goals of the research while ensuring protection of the Alaska subsistence lifestyle. These protocols could also be used in a larger context to address concerns over increased vessel traffic from other activities. We will outline the importance of establishing the guidelines, describe the general process, and highlight examples of positive interactions with Alaska Native hunters during scientific research operations using this protocol.

  17. Birds and wind turbines: can they co-exist?

    International Nuclear Information System (INIS)

    1996-01-01

    This one-day seminar was intended to provide a forum for information exchange and discussion between those concerned with the potential effects of wind turbines on bird life and to produce recommendations that would be helpful in future wind power developments, environmental impact assessments and related research activities. The six papers presented cover the following topics: impacts, mitigation and monitoring of collisions, disturbance in the construction phase and habitat loss; bird protection and the law with particular reference to the burden of proof required from developers in a planning context in the United Kingdom; continuing studies on the birds of Blyth Harbour in the UK where nine 300kW wind turbines are mounted on a pier jutting out into the sea; an overview of European and American experience; the policy and experience of the Royal Society for the Protection of Birds; wind farm design in the light of previous experience. The discussion arising out of each paper is summarised. (UK)

  18. Birds and wind turbines: can they co-exist?

    International Nuclear Information System (INIS)

    Still, David.

    1996-01-01

    The wind farm is situated along an exposed pier at Blyth Harbour and has now been designated as part of a SSI and part of a proposed RAMSAR site. The bird activity within the harbour is high and is also the wintering home of the Purple Sandpiper. An offshore wind farm is proposed for the area, one kilometre from the pier. Two turbines will be erected with the support of the European Commission THERMIE Programme. The bird study at Blyth has been funded by Border Wind, Blyth Harbour Wind Farm Company and the DTI as part of an ETSU funded study. (UK)

  19. Sonographic assessment of pregnancy co-existing with uterine ...

    African Journals Online (AJOL)

    EB

    but the fibroids are usually innocent bystanders.4 They cause only 2% to 3% of cases of infertility. Fibroids that block one or both of the fallopian tubes may prevent sperm from fertilizing an egg while fibroids that fill the uterine cavity may block implantation of a newly fertilized egg.5. Based on risk factors for myoma ...

  20. Added value, co-existence and the environment

    International Nuclear Information System (INIS)

    Grimsrud, Bjoerne

    2004-01-01

    Based on interviews and data from various studies of the Northern Norway, it is concluded that establishing oil industry in Northern Norway will have a positive co-localisation effect on other industries in the region. The analysis is based on models from economic geography affirming that the establishment or termination of an enterprise creates positive or negative effects for the availability and input factor cost for other companies in the same place (ml)

  1. The co-existence of primary hyperparathyroidism and osteogenesis imperfecta.

    Science.gov (United States)

    Salti, I S; Nassar, V H; Bulos, S

    1973-04-07

    A 47-year-old patient suffering from osteogenesis imperfecta was found to have mild hypercalcemia. The latter proved to be due to a parathyroid adenoma. The clinical and laboratory features of this association are summarized, and the implications of serum calcium abnormalities in osteogenesis imperfecta are discussed.

  2. Adsorbent catalytic nanoparticles and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-01-31

    The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

  3. Contributions to the theory of catalytic titrations-III Neutralization catalytic titrations.

    Science.gov (United States)

    Gaál, F F; Abramović, B F

    1985-07-01

    Neutralization catalytic titrations of weak monoprotic adds and bases with both volumetric and coulometric addition of the titrant (strong base/acid) have been simulated by taking into account the equilibrium concentration of the catalyst during the titration. The influence of several factors on the shape of the simulated catalytic titration curve has been investigated and is discussed.

  4. Catalytic non-thermal plasma reactor for the decomposition of a ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... 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 ...

  5. Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide

    NARCIS (Netherlands)

    Wang, Y.M.; Magusin, P.C.M.M.; Santen, van R.A.; Abbenhuis, H.C.L.

    2007-01-01

    Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide were synthesized through the acid-catalyzed hydrolysis and co-condensation of organotrialkoxysilane monomers and a,¿-bis(trialkoxysilyl) alkane cross-linkers in ethanol–water solution, with

  6. Catalytic steam reforming of ethanol for hydrogen production: Brief status

    Directory of Open Access Journals (Sweden)

    Bineli Aulus R.R.

    2016-01-01

    Full Text Available Hydrogen represents a promising fuel since it is considered as a cleanest energy carrier and also because during its combustion only water is emitted. It can be produced from different kinds of renewable feedstocks, such as ethanol, in this sense hydrogen could be treated as biofuel. Three chemical reactions can be used to achieve this purpose: the steam reforming (SR, the partial oxidation (POX and the autothermal reforming (ATR. In this study, the catalysts implemented in steam reforming of ethanol were reviewed. A wide variety of elements can be used as catalysts for this reaction, such as base metals (Ni, Cu and Co or noble metals (Rh, Pt and Ru usually deposited on a support material that increases surface area and improves catalytic function. The use of Rh, Ni and Pt supported or promoted with CeO2, and/or La2O3 shows excellent performance in ethanol SR catalytic process. The ratio of water to ethanol, reaction temperatures, catalysts loadings, selectivity and activity are also discussed as they are extremely important for high hydrogen yields.

  7. Atomically Precise Metal Nanoclusters for Catalytic Application

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Rongchao [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2016-11-18

    The central goal of this project is to explore the catalytic application of atomically precise gold nanoclusters. By solving the total structures of ligand-protected nanoclusters, we aim to correlate the catalytic properties of metal nanoclusters with their atomic/electronic structures. Such correlation unravel some fundamental aspects of nanocatalysis, such as the nature of particle size effect, origin of catalytic selectivity, particle-support interactions, the identification of catalytically active centers, etc. The well-defined nanocluster catalysts mediate the knowledge gap between single crystal model catalysts and real-world conventional nanocatalysts. These nanoclusters also hold great promise in catalyzing certain types of reactions with extraordinarily high selectivity. These aims are in line with the overall goals of the catalytic science and technology of DOE and advance the BES mission “to support fundamental research to understand, predict, and ultimately control matter and energy at the level of electrons, atoms, and molecules”. Our group has successfully prepared different sized, robust gold nanoclusters protected by thiolates, such as Au25(SR)18, Au28(SR)20, Au38(SR)24, Au99(SR)42, Au144(SR)60, etc. Some of these nanoclusters have been crystallographically characterized through X-ray crystallography. These ultrasmall nanoclusters (< 2 nm diameter) exhibit discrete electronic structures due to quantum size effect, as opposed to quasicontinuous band structure of conventional metal nanoparticles or bulk metals. The available atomic structures (metal core plus surface ligands) of nanoclusters serve as the basis for structure-property correlations. We have investigated the unique catalytic properties of nanoclusters (i.e. not observed in conventional nanogold catalysts) and revealed the structure-selectivity relationships. Highlights of our

  8. Water

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-08-01

    Full Text Available Water scarcity is without a doubt on of the greatest threats to the human species and has all the potential to destabilise world peace. Falling water tables are a new phenomenon. Up until the development of steam and electric motors, deep groudwater...

  9. Water

    OpenAIRE

    Hertie School of Governance

    2010-01-01

    All human life depends on water and air. The sustainable management of both is a major challenge for today's public policy makers. This issue of Schlossplatz³ taps the streams and flows of the current debate on the right water governance.

  10. Deuterium and heavy water

    International Nuclear Information System (INIS)

    Vasaru, G.; Ursu, D.; Mihaila, A.; Szentgyorgyi, P.

    1975-01-01

    This bibliography on deuterium and heavy water contains 3763 references (1932-1974) from 43 sources of information. An author index and a subject index are given. The latter contains a list of 136 subjects, arranged in 13 main topics: abundance of deuterium , catalysts, catalytic exchange, chemical equilibria, chemical kinetics, deuterium and heavy water analysis, deuterium and heavy water properties, deuterium and heavy water separation, exchange reactions, general review, heavy water as moderator, isotope effects, synthesis of deuterium compounds

  11. Catalytic reduction of NO by methane using a Pt/C/polybenzimidazole/Pt/C fuel cell

    DEFF Research Database (Denmark)

    Petrushina, Irina; Cleemann, Lars Nilausen; Refshauge, Rasmus

    2007-01-01

    with participation of H+ or electrochemically produced hydrogen. When added, methane partially suppresses the electrochemical reduction of NO. Methane outlet concentration monitoring has shown the CH4 participation in the chemical catalytic reduction, i.e., methane co-adsorption with NO inhibited the electrochemical...... NO reduction and introduced a dominant chemical path of the NO reduction. The products of the NO reduction with methane were N2, C2H4, and water. The catalytic NO reduction by methane was promoted when the catalyst was negatively polarized (−0.2 V). Repeated negative polarization of the catalyst increased...

  12. Nitrogen removal from wastewater by a catalytic oxidation method.

    Science.gov (United States)

    Huang, T L; Macinnes, J M; Cliffe, K R

    2001-06-01

    The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

  13. Biodiesel from waste cooking oil via base-catalytic and supercritical methanol transesterification

    International Nuclear Information System (INIS)

    Demirbas, Ayhan

    2009-01-01

    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

  14. 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.

  15. 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.

  16. 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...

  17. Modeling and simulation of heterogeneous catalytic processes

    CERN Document Server

    Dixon, Anthony

    2014-01-01

    Heterogeneous catalysis and mathematical modeling are essential components of the continuing search for better utilization of raw materials and energy, with reduced impact on the environment. Numerical modeling of chemical systems has progressed rapidly due to increases in computer power, and is used extensively for analysis, design and development of catalytic reactors and processes. This book presents reviews of the state-of-the-art in modeling of heterogeneous catalytic reactors and processes. Reviews by leading authorities in the respective areas Up-to-date reviews of latest techniques in modeling of catalytic processes Mix of US and European authors, as well as academic/industrial/research institute perspectives Connections between computation and experimental methods in some of the chapters.

  18. Water

    Directory of Open Access Journals (Sweden)

    E. Sanmuga Priya

    2017-05-01

    Full Text Available Phytoremediation through aquatic macrophytes treatment system (AMATS for the removal of pollutants and contaminants from various natural sources is a well established environmental protection technique. Water hyacinth (Eichhornia crassipes, a worst invasive aquatic weed has been utilised for various research activities over the last few decades. The biosorption capacity of the water hyacinth in minimising various contaminants present in the industrial wastewater is well studied. The present review quotes the literatures related to the biosorption capacity of the water hyacinth in reducing the concentration of dyestuffs, heavy metals and minimising certain other physiochemical parameters like TSS (total suspended solids, TDS (total dissolved solids, COD (chemical oxygen demand and BOD (biological oxygen demand in textile wastewater. Sorption kinetics through various models, factors influencing the biosorption capacity, and role of physical and chemical modifications in the water hyacinth are also discussed.

  19. Catalytic Wastewater Treatment Using Pillared Clays

    Science.gov (United States)

    Perathoner, Siglinda; Centi, Gabriele

    After introduction on the use of solid catalysts in wastewater treatment technologies, particularly advanced oxidation processes (AOPs), this review discussed the use of pillared clay (PILC) materials in three applications: (i) wet air catalytic oxidation (WACO), (ii) wet hydrogen peroxide catalytic oxidation (WHPCO) on Cu-PILC and Fe-PILC, and (iii) behavior of Ti-PILC and Fe-PILC in the photocatalytic or photo-Fenton conversion of pollutants. Literature data are critically analyzed to evidence the main direction to further investigate, in particularly with reference to the possible practical application of these technologies to treat industrial, municipal, or agro-food production wastewater.

  20. Catalytic Kinetic Resolution of Biaryl Compounds.

    Science.gov (United States)

    Ma, Gaoyuan; Sibi, Mukund P

    2015-08-10

    Biaryl compounds with axial chirality are very common in synthetic chemistry, especially in catalysis. Axially chiral biaryls are important due to their biological activities and extensive applications in asymmetric catalysis. Thus the development of efficient enantioselective methods for their synthesis has attracted considerable attention. This Minireview discusses the progress made in catalytic kinetic resolution of biaryl compounds and chronicles significant advances made recently in catalytic kinetic resolution of biaryl scaffolds. © 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. 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.

  2. Janus droplet as a catalytic micromotor

    Science.gov (United States)

    Shklyaev, Sergey

    2015-06-01

    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 μ \\text{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 the Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers.

  3. Catalytic burners in larger boiler appliances

    Energy Technology Data Exchange (ETDEWEB)

    Silversand, Fredrik; Persson, Mikael (Catator AB, Lund (Sweden))

    2009-02-15

    This project focuses on the scale up of a Catator's catalytic burner technology to enable retrofit installation in existing boilers and the design of new innovative combinations of catalytic burners and boilers. Different design approaches are discussed and evaluated in the report and suggestions are made concerning scale-up. Preliminary test data, extracted from a large boiler installation are discussed together with an accurate analysis of technical possibilities following an optimization of the boiler design to benefit from the advantages of catalytic combustion. The experimental work was conducted in close collaboration with ICI Caldaie (ICI), located in Verona, Italy. ICI is a leading European boiler manufacturer in the effect segment ranging from about 20 kWt to several MWt. The study shows that it is possibly to scale up the burner technology and to maintain low emissions. The boilers used in the study were designed around conventional combustion and were consequently not optimized for implementation of catalytic burners. From previous experiences it stands clear that the furnace volume can be dramatically decreased when applying catalytic combustion. In flame combustion, this volume is normally dimensioned to avoid flame impingement on cold surfaces and to facilitate completion of the gas-phase reactions. The emissions of nitrogen oxides can be reduced by decreasing the residence time in the furnace. Even with the over-dimensioned furnace used in this study, we easily reached emission values close to 35 mg/kWh. The emissions of carbon monoxide and unburned hydrocarbons were negligible (less than 5 ppmv). It is possible to decrease the emissions of nitrogen oxides further by designing the furnace/boiler around the catalytic burner, as suggested in the report. Simultaneously, the size of the boiler installation can be reduced greatly, which also will result in material savings, i.e. the production cost can be reduced. It is suggested to optimize the

  4. 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.)

  5. Using electron beams to investigate catalytic materials

    International Nuclear Information System (INIS)

    Zhang, Bingsen; Su, Dang Sheng

    2014-01-01

    Transmission Electron microscopy (TEM) enables us, not only to reveal the morphology, but also to provide structural, chemical and electronic information about solid catalysts at the atomic level, providing a dramatic driving force for the development of heterogeneous catalysis. Almost all catalytic materials have been studied with TEM in order to obtain information about their structures, which can help us to establish the synthesis-structure-property relationships and to design catalysts with new structures and desired properties. Herein, several examples will be reviewed to illustrate the investigation of catalytic materials by using electron beams. (authors)

  6. Water Purification

    Science.gov (United States)

    1994-01-01

    The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

  7. Exploration of alternate catalytic mechanisms and optimization strategies for retroaldolase design.

    Science.gov (United States)

    Bjelic, Sinisa; Kipnis, Yakov; Wang, Ling; Pianowski, Zbigniew; Vorobiev, Sergey; Su, Min; Seetharaman, Jayaraman; Xiao, Rong; Kornhaber, Gregory; Hunt, John F; Tong, Liang; Hilvert, Donald; Baker, David

    2014-01-09

    Designed retroaldolases have utilized a nucleophilic lysine to promote carbon-carbon bond cleavage of β-hydroxy-ketones via a covalent Schiff base intermediate. Previous computational designs have incorporated a water molecule to facilitate formation and breakdown of the carbinolamine intermediate to give the Schiff base and to function as a general acid/base. Here we investigate an alternative active-site design in which the catalytic water molecule was replaced by the side chain of a glutamic acid. Five out of seven designs expressed solubly and exhibited catalytic efficiencies similar to previously designed retroaldolases for the conversion of 4-hydroxy-4-(6-methoxy-2-naphthyl)-2-butanone to 6-methoxy-2-naphthaldehyde and acetone. After one round of site-directed saturation mutagenesis, improved variants of the two best designs, RA114 and RA117, exhibited among the highest kcat (>10(-3)s(-1)) and kcat/KM (11-25M(-1)s(-1)) values observed for retroaldolase designs prior to comprehensive directed evolution. In both cases, the >10(5)-fold rate accelerations that were achieved are within 1-3 orders of magnitude of the rate enhancements reported for the best catalysts for related reactions, including catalytic antibodies (kcat/kuncat=10(6) to 10(8)) and an extensively evolved computational design (kcat/kuncat>10(7)). The catalytic sites, revealed by X-ray structures of optimized versions of the two active designs, are in close agreement with the design models except for the catalytic lysine in RA114. We further improved the variants by computational remodeling of the loops and yeast display selection for reactivity of the catalytic lysine with a diketone probe, obtaining an additional order of magnitude enhancement in activity with both approaches. © 2013.

  8. 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.

  9. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption – Catalytic wet air oxidation on activated carbons

    International Nuclear Information System (INIS)

    Quesada-Peñate, I.; Julcour-Lebigue, C.; Jáuregui-Haza, U.J.; Wilhelm, A.M.; Delmas, H.

    2012-01-01

    Highlights: ► Three activated carbons (AC) compared as adsorbents and oxidation catalysts. ► Similar evolution for catalytic and adsorptive properties of AC over reuses. ► Acidic and mesoporous AC to be preferred, despite lower initial efficiency. ► Oxidative degradation of paracetamol improves biodegradability. ► 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.

  10. Fluid catalytic cracking : Feedstocks and reaction mechanism

    NARCIS (Netherlands)

    Dupain, X.

    2006-01-01

    The Fluid Catalytic Cracking (FCC) process is one of the key units in a modern refinery. Traditionally, its design is primarily aimed for the production of gasoline from heavy oil fractions, but as co-products also diesel blends and valuable gasses (e.g. propene and butenes) are formed in

  11. Kinetic equation of heterogeneous catalytic isotope exchange

    Energy Technology Data Exchange (ETDEWEB)

    Trokhimets, A I [AN Belorusskoj SSR, Minsk. Inst. Fiziko-Organicheskoj Khimii

    1979-12-01

    A kinetic equation is derived for the bimolecular isotope exchange reaction between AXsub(n)sup(*) and BXsub(m)sup(o), all atoms of element X in each molecule being equivalent. The equation can be generalized for homogeneous and heterogeneous catalytic isotope exchange.

  12. Complementary structure sensitive and insensitive catalytic relationships

    NARCIS (Netherlands)

    Santen, van R.A.

    2009-01-01

    The burgeoning field of nanoscience has stimulated an intense interest in properties that depend on particle size. For transition metal particles, one important property that depends on size is catalytic reactivity, in which bonds are broken or formed on the surface of the particles. Decreased

  13. 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…

  14. 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...... understanding of the nature of the electrochemical promotion is also presented....

  15. 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.

  16. 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....

  17. Catalytic asymmetric synthesis of the alkaloid (+)-myrtine

    NARCIS (Netherlands)

    Pizzuti, Maria Gabriefla; Minnaard, Adriaan J.; Feringa, Ben L.

    2008-01-01

    A new protocol for the asymmetric synthesis of trans-2,6-disubstituted-4-piperidones has been developed using a catalytic enantioselective conjugate addition reaction in combination with a diastereoselective lithiation-substitution sequence; an efficient synthesis of (+)-myrtine has been achieved

  18. Catalytic oxidation of cyclohexane to cyclohexanone

    Indian Academy of Sciences (India)

    ... a precursor and characterized by chemical analysis using the ICP–AES method, XRD, TEM, FTIR and BET surface area determination. The oxidation reaction was carried out at 70°C under atmospheric pressure. The results showed the catalytic performance of Pt/Al2O3 as being very high in terms of turnover frequency.

  19. 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...

  20. Flame assisted synthesis of catalytic ceramic membranes

    DEFF Research Database (Denmark)

    Johansen, Johnny; Mosleh, Majid; Johannessen, Tue

    2004-01-01

    technology it is possible to make supported catalysts, composite metal oxides, catalytically active surfaces, and porous ceramic membranes. Membrane layers can be formed by using a porous substrate tube (or surface) as a nano-particle filter. The aerosol gas from the flame is led through a porous substrate...

  1. Sintering of Catalytic Nanoparticles: Particle Migration or Ostwald Ripening?

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; DeLaRiva, Andrew T.; Challa, Sivakumar R.

    2013-01-01

    deactivation, is an important mechanism for the loss of catalyst activity. This is especially true for high temperature catalytic processes, such as steam reforming, automotive exhaust treatment, or catalytic combustion. With dwindling supplies of precious metals and increasing demand, fundamental...

  2. Catalytic characterization of bi-functional catalysts derived from Pd ...

    Indian Academy of Sciences (India)

    Unknown

    1995; Lyubovsky and Pfefferle 1999; Sales et al 1999;. Hill et al 2000). ... For a catalytic system, whose activity ... catalytic systems containing Pd, supported on various acid- ..... Further studies are needed to optimize a balance between.

  3. Catalytically favorable surface patterns in Pt-Au nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    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

  4. 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.

  5. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  6. Triblock copolymer-mediated synthesis of catalytically active gold nanostructures

    Science.gov (United States)

    Santos, Douglas C.; de Souza, Viviane C.; Vasconcelos, Diego A.; Andrade, George R. S.; Gimenez, Iara F.; Teixeira, Zaine

    2018-04-01

    The design of nanostructures based on poly(ethylene oxide)-poly(propylene)-poly(ethylene oxide) (PEO-PPO-PEO) and metal nanoparticles is becoming an important research topic due to their multiple functionalities in different fields, including nanomedicine and catalysis. In this work, water-soluble gold nanoparticles have been prepared through a green aqueous synthesis method using Pluronic F127 as both reducing and stabilizing agents. The size dependence (varying from 2 to 70 nm) and stability of gold nanoparticles were systematically studied by varying some parameters of synthesis, which were the polymer concentration, temperature, and exposure to UV-A light, being monitored by UV-Vis spectroscopy and TEM. Also, an elaborated study regarding to the kinetic of formation (nucleation and growth) was presented. Finally, the as-prepared Pluronic-capped gold nanoparticles have shown excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride, in which a higher catalytic performance was exhibited when compared with gold nanoparticles prepared by classical reduction method using sodium citrate. [Figure not available: see fulltext.

  7. Catalytic degradation of brominated flame retardants by copper oxide nanoparticles

    Science.gov (United States)

    Dror, I.; Yecheskel, Y.; Berkowitz, B.

    2013-12-01

    Brominated flame retardants (BFRs) have been added to various products like plastic, textile, electronics and synthetic polymers at growing rates. In spite of the clear advantages of reducing fire damages, many of these BFRs may be released to the environment after their beneficial use which may lead to contamination of water resources. In this work we present the catalytic degradation of two brominated flame retardants (BFRs), tribromoneopentyl alcohol (TBNPA) and 2,4 dibromophenol (2,4-DBP) by copper oxide nanoparticles (nCuO) in aqueous solution. The degradation kinetics, the debromination, and the formation of intermediates by nCuO catalysis are compared to Fenton oxidation and to reduction by nano zero-valent iron (nZVI). The two studied BFRs are shown to degrade fully by the nCuO system within hours to days. Shorter reaction times showed differences in reaction pathways and kinetics for the two compounds. The 2,4-DBP showed faster degradation than TBNPA, by nCuO catalysis. Relatively high resistance to degradation was recorded for 2,4-DBP with nZVI, yielding 20% degradation after 24 h, while the TBNPA was degraded by 85% within 12 hours. A catalytic mechanism for radical generation and BFR degradation by nCuO is proposed. It is further suggested that H2O2 plays an essential role in the activation of the catalyst.

  8. Catalytic site identification—a web server to identify catalytic site structural matches throughout PDB

    Science.gov (United States)

    Kirshner, Daniel A.; Nilmeier, Jerome P.; Lightstone, Felice C.

    2013-01-01

    The catalytic site identification web server provides the innovative capability to find structural matches to a user-specified catalytic site among all Protein Data Bank proteins rapidly (in less than a minute). The server also can examine a user-specified protein structure or model to identify structural matches to a library of catalytic sites. Finally, the server provides a database of pre-calculated matches between all Protein Data Bank proteins and the library of catalytic sites. The database has been used to derive a set of hypothesized novel enzymatic function annotations. In all cases, matches and putative binding sites (protein structure and surfaces) can be visualized interactively online. The website can be accessed at http://catsid.llnl.gov. PMID:23680785

  9. 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.

  10. An Assessment of the Technical Readiness of the Vapor Phase Catalytic Ammonia Removal Process (VPCAR) Technology

    Science.gov (United States)

    Flynn, Michael

    2000-01-01

    This poster provides an assessment of the technical readiness of the Vapor Phase Catalytic Ammonia Removal Process (VPCAR). The VPCAR technology is a fully regenerative water recycling technology designed specifically for applications such as a near term Mars exploration mission. The VPCAR technology is a highly integrated distillation/catalytic oxidation based water processor. It is designed to accept a combined wastewater stream (urine, condensate, and hygiene) and produces potable water in a single process step which requires -no regularly scheduled re-supply or maintenance for a 3 year mission. The technology is designed to be modular and to fit into a volume comparable to a single International Space Station Rack (when sized for a crew of 6). This poster provides a description of the VPCAR technology and a summary of the current performance of the technology. Also provided are the results of two separate NASA sponsored system trade studies which investigated the potential payback of further development of the VPCAR technology.

  11. Catalytic methods using molecular oxygen for treatment of PMMS and ECLSS waste streams, volume 2

    Science.gov (United States)

    Akse, James R.

    1992-01-01

    Catalytic oxidation has proven to be an effective addition to the baseline sorption, ion exchange water reclamation technology which will be used on Space Station Freedom (SSF). Low molecular weight, polar organics such as alcohols, aldehydes, ketones, amides, and thiocarbamides which are poorly removed by the baseline multifiltration (MF) technology can be oxidized to carbon dioxide at low temperature (121 C). The catalytic oxidation process by itself can reduce the Total Organic Carbon (TOC) to below 500 ppb for solutions designed to model these waste waters. Individual challenges by selected contaminants have shown only moderate selectivity towards particular organic species. The combined technology is applicable to the more complex waste water generated in the Process Materials Management System (PMMS) and Environmental Control and Life Support System (ECLSS) aboard SSF. During the phase 3 Core Module Integrated Facility (CMIF) water recovery tests at NASA MSFC, real hygiene waste water and humidity condensate were processed to meet potable specifications by the combined technology. A kinetic study of catalytic oxidation demonstrates that the Langmuir-Hinshelwood rate equation for heterogeneous catalysts accurately represent the kinetic behavior. From this relationship, activation energy and rate constants for acetone were determined.

  12. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons.

    Science.gov (United States)

    Quesada-Peñate, I; Julcour-Lebigue, C; Jáuregui-Haza, U J; Wilhelm, A M; Delmas, H

    2012-06-30

    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. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Catalytic Ethanol Dehydration to Ethylene over Nanocrystalline χ- and γ-Al2O3 Catalysts.

    Science.gov (United States)

    Janlamool, Jakrapan; Jongsomjit, Bunjerd

    2017-01-01

    The study is aimed to investigate the combination of nanocrystalline γ- and χ- alumina that displays the attractive chemical and physical properties for the catalytic dehydration of ethanol. The correlation between the acid density and ethanol conversion was observed. The high acid density apparently results in high catalytic activity, especially for the equally mixed γ- and χ- phase alumina (G50C50). In order to obtain a better understanding on how different catalysts would affect the ethylene yield, one of the most powerful techniques such as X-ray photoelectron spectroscopy (XPS) was performed. Hence, the different O 1s surface atoms can be identified and divided into three types including lattice oxygen (O, 530.7 eV), surface hydroxyl (OH, 532.1 eV) and lattice water (H 2 O, 532.9 eV). It was remarkably found that the large amount of O 1s surface atoms in lattice water can result in increased ethylene yield. In summary, the appearance of metastable χ-alumina structure exhibited better catalytic activity and ethylene yield than γ- alumina. Thus, the introduction of metastable χ- alumina structure into γ- alumina enhanced catalytic activity and ethylene yield. As the result, it was found that the G50C50 catalyst exhibits the ethylene yield (80%) at the lowest reaction temperature ca. 250°C among other catalysts.

  14. Electrochemical, H2O2-Boosted Catalytic Oxidation System

    Science.gov (United States)

    Akse, James R.; Thompson, John O.; Schussel, Leonard J.

    2004-01-01

    An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen water-sterilizing systems in the way in which it increases oxidation capabilities, supplies H2O2 when needed, reduces the total organic carbon (TOC) content of treated water to a low level, consumes less energy than prior systems do, reduces the risk of contamination, and costs less to operate. This system was developed as a variant of part of an improved waste-management subsystem of the life-support system of a spacecraft. Going beyond its original intended purpose, it offers the advantage of being able to produce H2O2 on demand for surface sterilization and/or decontamination: this is a major advantage inasmuch as the benign byproducts of this H2O2 system, unlike those of systems that utilize other chemical sterilants, place no additional burden of containment control on other spacecraft air- or water-reclamation systems.

  15. Advances in solid-catalytic and non-catalytic technologies for biodiesel production

    International Nuclear Information System (INIS)

    Islam, Aminul; Taufiq-Yap, Yun Hin; Chan, Eng-Seng; Moniruzzaman, M.; Islam, Saiful; Nabi, Md. Nurun

    2014-01-01

    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

  16. Catalytic silica particles via template-directed molecular imprinting

    Energy Technology Data Exchange (ETDEWEB)

    Markowitz, M.A.; Kust, P.R.; Deng, G.; Schoen, P.E.; Dordick, J.S.; Clark, D.S.; Gaber, B.P.

    2000-02-22

    The surfaces of silica particle were molecularly imprinted with an {alpha}-chymotrypsin transition-state analogue (TSA) by utilizing the technique of template-directed synthesis of mineralized materials. The resulting catalytic particles hydrolyzed amides in an enantioselective manner. A mixture of a nonionic surfactant and the acylated chymotrysin TSA, with the TSA acting as the headgroup at the surfactant-water interface, was used to form a microemulsion for silica particle formation. Incorporation of amine-, dihydroimidazole-, and carboxylate-terminated trialkoxysilanes into the particles during imprinting resulted in enhancement of the rates of amide hydrolysis. Acylated imprint molecules formed more effective imprints in the presence of the functionalized silanes than nonacylated imprint molecules. Particles surface-imprinted with the chymotrypsin TSA were selective for the trypsin substrate, and particles surface-imprinted with the L-isomer of the enzyme TSA were enantioselective for the D-isomer of the substrate.

  17. Functional tuning of the catalytic residue pKa in a de novo designed esterase.

    Science.gov (United States)

    Hiebler, Katharina; Lengyel, Zsófia; Castañeda, Carlos A; Makhlynets, Olga V

    2017-09-01

    AlleyCatE is a de novo designed esterase that can be allosterically regulated by calcium ions. This artificial enzyme has been shown to hydrolyze p-nitrophenyl acetate (pNPA) and 4-nitrophenyl-(2-phenyl)-propanoate (pNPP) with high catalytic efficiency. AlleyCatE was created by introducing a single-histidine residue (His 144 ) into a hydrophobic pocket of calmodulin. In this work, we explore the determinants of catalytic properties of AlleyCatE. We obtained the pK a value of the catalytic histidine using experimental measurements by NMR and pH rate profile and compared these values to those predicted from electrostatics pK a calculations (from both empirical and continuum electrostatics calculations). Surprisingly, the pK a value of the catalytic histidine inside the hydrophobic pocket of calmodulin is elevated as compared to the model compound pK a value of this residue in water. We determined that a short-range favorable interaction with Glu 127 contributes to the elevated pK a of His 144 . We have rationally modulated local electrostatic potential in AlleyCatE to decrease the pK a of its active nucleophile, His 144 , by 0.7 units. As a direct result of the decrease in the His 144 pK a value, catalytic efficiency of the enzyme increased by 45% at pH 6. This work shows that a series of simple NMR experiments that can be performed using low field spectrometers, combined with straightforward computational analysis, provide rapid and accurate guidance to rationally improve catalytic efficiency of histidine-promoted catalysis. Proteins 2017; 85:1656-1665. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Selective catalytic reduction of NO{sub x} by olefins

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, F

    1997-12-31

    The removal of nitrogen oxides from the exhaust of lean-burn gasoline fuelled and diesel-fuelled engines, operating under net oxidizing conditions, has recently attracted considerable attention. In this work, three different catalytic systems (Al{sub 2}O{sub 3}, Cu/Al{sub 2}O{sub 3} and Cu/ZSM-5) are investigated for their suitability as catalysts for the selective reduction of nitrogen oxides by hydrocarbons in excess oxygen. Special emphasis is given to the formation of potentially harmful byproducts such as hydrogen cyanide (HCN), cyanic acid (HNCO), ammonia (NH{sub 3}) and nitrous oxide (N{sub 2}O). The effect of reaction temperature, nitrogen oxide (NO, NO{sub 2}), hydrocarbon (ethene, propene) and water on activity and the formation of byproducts is investigated. In situ FTIR spectroscopy and temperature-programmed surface reactions (TPSR) of absorbed species in different atmospheres were used to investigate the nature and reactivity of adsorbates formed under reaction conditions. The catalytic activity was strongly influenced by the presence of water in the feed. The effects of the other parameters were suppressed and the performance generally decreased, except when propene was used for the reduction of NO{sub x} over Cu/ZSM-5. Over Cu/ZSM-5 clearly higher conversion was obtained, when ethene was used as reducing agent, while there was no significant difference when starting from NO or NO{sub 2}. In contrast, with {gamma}-Al{sub 2}O{sub 3} NO{sub 2} was reduced more efficiently than NO with both reductants. The impregnation of {gamma}-Al{sub 2}O{sub 3} with copper led to an extensive loss of this performance. For dry feeds and with increasing CuO loading, the catalysts reached maximum activity at lower temperature and the maximum yield of nitrogen slightly decreased. (author) figs., tabs., refs.

  19. On the Structural Context and Identification of Enzyme Catalytic Residues

    Directory of Open Access Journals (Sweden)

    Yu-Tung Chien

    2013-01-01

    Full Text Available 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 results show that catalytic residues have distinct structural features and context. Their neighboring residues, whether sequence or structure neighbors within specific range, are usually structurally more rigid than those of noncatalytic residues. The structural context feature is combined with support vector machine to identify catalytic residues from enzyme structure. The prediction results are better or comparable to those of recent structure-based prediction methods.

  20. Effect of inlet cone pipe angle in catalytic converter

    Science.gov (United States)

    Amira Zainal, Nurul; Farhain Azmi, Ezzatul; Arifin Samad, Mohd

    2018-03-01

    The catalytic converter shows significant consequence to improve the performance of the vehicle start from it launched into production. Nowadays, the geometric design of the catalytic converter has become critical to avoid the behavior of backpressure in the exhaust system. The backpressure essentially reduced the performance of vehicles and increased the fuel consumption gradually. Consequently, this study aims to design various models of catalytic converter and optimize the volume of fluid flow inside the catalytic converter by changing the inlet cone pipe angles. Three different geometry angles of the inlet cone pipe of the catalytic converter were assessed. The model is simulated in Solidworks software to determine the optimum geometric design of the catalytic converter. The result showed that by decreasing the divergence angle of inlet cone pipe will upsurge the performance of the catalytic converter.

  1. Catalytic combustion for the elimination of methane, BTEX and other VOC : IV

    International Nuclear Information System (INIS)

    Hayes, R.E.; Wanke, S.E.

    2008-01-01

    Options for volatile organic compound combustion include homogeneous combustion (flaring) or catalytic combustion involving a flameless combustion process that uses a solid catalyst to promote the combustion reaction. This presentation discussed relative reactivity testing for volatile organic compounds (VOCs) over commercial catalysts. Several commercial pad catalysts were tested, as well as other powders. The relative reactivity of methane as well as benzene, toluene, ethylbenzene, and xylene (BTEX) were investigated. The purpose of the project was to evaluate combustion of concentrated methane streams that contained BTEX compounds; evaluate catalytic combustion using a counter diffusive radiant heater; develop mathematical models for the reactor to enhance design and understanding; improve the catalyst for BTEX combustion; and target application-dehydrator units. Topics that were addressed in the presentation included methane and benzene conversion; catalytic radiant heaters; small industrial and commercial units; measured temperature distribution; fuel slippage, methane conversion; the effect of water and hydrocarbons; the effect of water-liquid injection; and water addition as vapour. Several observations were offered, including that high percentages of injected liquid water can reduce reactor operating temperature; combustion of BTEX remained highly efficient, however liquid injection could also cause temperature reductions and ultimately the reactor would extinguish; and pre-heating the feed can eliminate the temperature drop and pad wetness problem. It was concluded that BTEX compounds are reactive, and the technology appears promising. 19 figs

  2. Catalytic combustion for the elimination of methane, BTEX and other VOC : IV

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, R.E.; Wanke, S.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2008-07-01

    Options for volatile organic compound combustion include homogeneous combustion (flaring) or catalytic combustion involving a flameless combustion process that uses a solid catalyst to promote the combustion reaction. This presentation discussed relative reactivity testing for volatile organic compounds (VOCs) over commercial catalysts. Several commercial pad catalysts were tested, as well as other powders. The relative reactivity of methane as well as benzene, toluene, ethylbenzene, and xylene (BTEX) were investigated. The purpose of the project was to evaluate combustion of concentrated methane streams that contained BTEX compounds; evaluate catalytic combustion using a counter diffusive radiant heater; develop mathematical models for the reactor to enhance design and understanding; improve the catalyst for BTEX combustion; and target application-dehydrator units. Topics that were addressed in the presentation included methane and benzene conversion; catalytic radiant heaters; small industrial and commercial units; measured temperature distribution; fuel slippage, methane conversion; the effect of water and hydrocarbons; the effect of water-liquid injection; and water addition as vapour. Several observations were offered, including that high percentages of injected liquid water can reduce reactor operating temperature; combustion of BTEX remained highly efficient, however liquid injection could also cause temperature reductions and ultimately the reactor would extinguish; and pre-heating the feed can eliminate the temperature drop and pad wetness problem. It was concluded that BTEX compounds are reactive, and the technology appears promising. 19 figs.

  3. Zeolitic catalytic conversion of alcohols to hydrocarbons

    Science.gov (United States)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2018-04-10

    A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

  4. Method to produce catalytically active nanocomposite coatings

    Science.gov (United States)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  5. Enantioselective catalytic fluorinative aza-semipinacol rearrangement.

    Science.gov (United States)

    Romanov-Michailidis, Fedor; Pupier, Marion; Besnard, Céline; Bürgi, Thomas; Alexakis, Alexandre

    2014-10-03

    An efficient and highly stereoselective fluorinative aza-semipinacol rearrangement is described. The catalytic reaction requires use of Selectfluor in combination with the chiral, enantiopure phosphate anion derived from acid L3. Under optimized conditions, cyclopropylamines A were transformed into β-fluoro cyclobutylimines B in good yields and high levels of diastereo- and enantiocontrol. Furthermore, the optically active cyclobutylimines were reduced diastereoselectively with L-Selectride in the corresponding fluorinated amines C, compounds of significant interest in the pharmacological industry.

  6. Zeolitic catalytic conversion of alochols to hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2017-01-03

    A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

  7. 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

  8. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Griffin, T.P.; Johnston, J.E.; Payea, B.M.; Zeitoon, B.M.

    1995-01-01

    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

  9. Method to produce catalytically active nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2017-12-19

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  10. Catalytic hydrogen recombination for nuclear containments

    International Nuclear Information System (INIS)

    Koroll, G.W.; Lau, D.W.P.; Dewit, W.A.; Graham, W.R.C.

    1994-01-01

    Catalytic recombiners appear to be a credible option for hydrogen mitigation in nuclear containments. The passive operation, versatility and ease of back fitting are appealing for existing stations and new designs. Recently, a generation of wet-proofed catalyst materials have been developed at AECL which are highly specific to H 2 -O 2 , are active at ambient temperatures and are being evaluated for containment applications. Two types of catalytic recombiners were evaluated for hydrogen removal in containments based on the AECL catalyst. The first is a catalytic combustor for application in existing air streams such as provided by fans or ventilation systems. The second is an autocatalytic recombiner which uses the enthalpy of reaction to produce natural convective flow over the catalyst elements. Intermediate-scale results obtained in 6 m 3 and 10 m 3 spherical and cylindrical vessels are given to demonstrate self-starting limits, operating limits, removal capacity, scaling parameters, flow resistance, mixing behaviour in the vicinity of an operating recombiner and sensitivity to poisoning, fouling and radiation. (author). 13 refs., 10 figs

  11. 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.

  12. Vapor-Driven Propulsion of Catalytic Micromotors

    Science.gov (United States)

    Dong, Renfeng; Li, Jinxing; Rozen, Isaac; Ezhilan, Barath; Xu, Tailin; Christianson, Caleb; Gao, Wei; Saintillan, David; Ren, Biye; Wang, Joseph

    2015-08-01

    Chemically-powered micromotors offer exciting opportunities in diverse fields, including therapeutic delivery, environmental remediation, and nanoscale manufacturing. However, these nanovehicles require direct addition of high concentration of chemical fuel to the motor solution for their propulsion. We report the efficient vapor-powered propulsion of catalytic micromotors without direct addition of fuel to the micromotor solution. Diffusion of hydrazine vapor from the surrounding atmosphere into the sample solution is instead used to trigger rapid movement of iridium-gold Janus microsphere motors. Such operation creates a new type of remotely-triggered and powered catalytic micro/nanomotors that are responsive to their surrounding environment. This new propulsion mechanism is accompanied by unique phenomena, such as the distinct off-on response to the presence of fuel in the surrounding atmosphere, and spatio-temporal dependence of the motor speed borne out of the concentration gradient evolution within the motor solution. The relationship between the motor speed and the variables affecting the fuel concentration distribution is examined using a theoretical model for hydrazine transport, which is in turn used to explain the observed phenomena. The vapor-powered catalytic micro/nanomotors offer new opportunities in gas sensing, threat detection, and environmental monitoring, and open the door for a new class of environmentally-triggered micromotors.

  13. Antibody proteases: induction of catalytic response.

    Science.gov (United States)

    Gabibov, A G; Friboulet, A; Thomas, D; Demin, A V; Ponomarenko, N A; Vorobiev, I I; Pillet, D; Paon, M; Alexandrova, E S; Telegin, G B; Reshetnyak, A V; Grigorieva, O V; Gnuchev, N V; Malishkin, K A; Genkin, D D

    2002-10-01

    Most of the data accumulated throughout the years on investigation of catalytic antibodies indicate that their production increases on the background of autoimmune abnormalities. The different approaches to induction of catalytic response toward recombinant gp120 HIV-1 surface protein in mice with various autoimmune pathologies are described. The peptidylphosphonate conjugate containing structural part of gp120 molecule is used for reactive immunization of NZB/NZW F1, MRL, and SJL mice. The specific modification of heavy and light chains of mouse autoantibodies with Val-Ala-Glu-Glu-Glu-Val-PO(OPh)2 reactive peptide was demonstrated. Increased proteolytic activity of polyclonal antibodies in SJL mice encouraged us to investigate the production of antigen-specific catalytic antibodies on the background of induced experimental autoimmune encephalomyelitis (EAE). The immunization of autoimmune-prone mice with the engineered fusions containing the fragments of gp120 and encephalitogenic epitope of myelin basic protein (MBP(89-104)) was made. The proteolytic activity of polyclonal antibodies isolated from the sera of autoimmune mice immunized by the described antigen was shown. Specific immune response of SJL mice to these antigens was characterized. Polyclonal antibodies purified from sera of the immunized animals revealed proteolytic activity. The antiidiotypic approach to raise the specific proteolytic antibody as an "internal image" of protease is described. The "second order" monoclonal antibodies toward subtilisin Carlsberg revealed pronounced proteolytic activity.

  14. Optimization of Cholinesterase-Based Catalytic Bioscavengers Against Organophosphorus Agents.

    Science.gov (United States)

    Lushchekina, Sofya V; Schopfer, Lawrence M; Grigorenko, Bella L; Nemukhin, Alexander V; Varfolomeev, Sergei D; Lockridge, Oksana; Masson, Patrick

    2018-01-01

    Organophosphorus agents (OPs) are irreversible inhibitors of acetylcholinesterase (AChE). OP poisoning causes major cholinergic syndrome. Current medical counter-measures mitigate the acute effects but have limited action against OP-induced brain damage. Bioscavengers are appealing alternative therapeutic approach because they neutralize OPs in bloodstream before they reach physiological targets. First generation bioscavengers are stoichiometric bioscavengers. However, stoichiometric neutralization requires administration of huge doses of enzyme. Second generation bioscavengers are catalytic bioscavengers capable of detoxifying OPs with a turnover. High bimolecular rate constants ( k cat / K m > 10 6 M -1 min -1 ) are required, so that low enzyme doses can be administered. Cholinesterases (ChE) are attractive candidates because OPs are hemi-substrates. Moderate OP hydrolase (OPase) activity has been observed for certain natural ChEs and for G117H-based human BChE mutants made by site-directed mutagenesis. However, before mutated ChEs can become operational catalytic bioscavengers their dephosphylation rate constant must be increased by several orders of magnitude. New strategies for converting ChEs into fast OPase are based either on combinational approaches or on computer redesign of enzyme. The keystone for rational conversion of ChEs into OPases is to understand the reaction mechanisms with OPs. In the present work we propose that efficient OP hydrolysis can be achieved by re-designing the configuration of enzyme active center residues and by creating specific routes for attack of water molecules and proton transfer. Four directions for nucleophilic attack of water on phosphorus atom were defined. Changes must lead to a novel enzyme, wherein OP hydrolysis wins over competing aging reactions. Kinetic, crystallographic, and computational data have been accumulated that describe mechanisms of reactions involving ChEs. From these studies, it appears that introducing

  15. Optimization of Cholinesterase-Based Catalytic Bioscavengers Against Organophosphorus Agents

    Directory of Open Access Journals (Sweden)

    Sofya V. Lushchekina

    2018-03-01

    Full Text Available Organophosphorus agents (OPs are irreversible inhibitors of acetylcholinesterase (AChE. OP poisoning causes major cholinergic syndrome. Current medical counter-measures mitigate the acute effects but have limited action against OP-induced brain damage. Bioscavengers are appealing alternative therapeutic approach because they neutralize OPs in bloodstream before they reach physiological targets. First generation bioscavengers are stoichiometric bioscavengers. However, stoichiometric neutralization requires administration of huge doses of enzyme. Second generation bioscavengers are catalytic bioscavengers capable of detoxifying OPs with a turnover. High bimolecular rate constants (kcat/Km > 106 M−1min−1 are required, so that low enzyme doses can be administered. Cholinesterases (ChE are attractive candidates because OPs are hemi-substrates. Moderate OP hydrolase (OPase activity has been observed for certain natural ChEs and for G117H-based human BChE mutants made by site-directed mutagenesis. However, before mutated ChEs can become operational catalytic bioscavengers their dephosphylation rate constant must be increased by several orders of magnitude. New strategies for converting ChEs into fast OPase are based either on combinational approaches or on computer redesign of enzyme. The keystone for rational conversion of ChEs into OPases is to understand the reaction mechanisms with OPs. In the present work we propose that efficient OP hydrolysis can be achieved by re-designing the configuration of enzyme active center residues and by creating specific routes for attack of water molecules and proton transfer. Four directions for nucleophilic attack of water on phosphorus atom were defined. Changes must lead to a novel enzyme, wherein OP hydrolysis wins over competing aging reactions. Kinetic, crystallographic, and computational data have been accumulated that describe mechanisms of reactions involving ChEs. From these studies, it appears that

  16. Mass transfer model liquid phase catalytic exchange column simulation applicable to any column composition profile

    Energy Technology Data Exchange (ETDEWEB)

    Busigin, A. [NITEK USA Inc., Ocala, FL (United States)

    2015-03-15

    Liquid Phase Catalytic Exchange (LPCE) is a key technology used in water detritiation systems. Rigorous simulation of LPCE is complicated when a column may have both hydrogen and deuterium present in significant concentrations in different sections of the column. This paper presents a general mass transfer model for a homogenous packed bed LPCE column as a set of differential equations describing composition change, and equilibrium equations to define the mass transfer driving force within the column. The model is used to show the effect of deuterium buildup in the bottom of an LPCE column from non-negligible D atom fraction in the bottom feed gas to the column. These types of calculations are important in the design of CECE (Combined Electrolysis and Catalytic Exchange) water detritiation systems.

  17. Synthesis and Investigation the Catalytic Behavior of Cr2O3 Nanoparticles

    Directory of Open Access Journals (Sweden)

    R. Karimian

    2013-03-01

    Full Text Available The use of an inorganic phase in water-in-oil (w/o microemulsion has recently received considerable attention for preparing metal oxide nanoparticles. This is a technique, which allows preparation of ultrafine metal oxide nanoparticles within the size range 40 to 80 nm. Preparation of nano chromium (III oxide studied investigated in the inverse microemulsion system. Therefore the nucleation of metal particles proceeds in the water capsules of the microemulsion. the main advantage of this method is easily controllable conditions with using low cost chromium source is merit to be considered for scaling up by industrial researchers. Besides we mainly focus on the catalytic property nano chromium (III oxide. Oxidation of aromatic aldehyde/alcohol to the corresponding carboxylic acids can be performed highly efficiently in the presence of a catalytic amount of nano chromium (III oxide in THF as solvent under mild conditions.

  18. Incorporation of catalytic dehydrogenation into fischer-tropsch synthesis to significantly reduce carbon dioxide emissions

    Science.gov (United States)

    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.

  19. 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.

  20. Stability and Catalytic Kinetics of Horseradish Peroxidase Confined in Nanoporous SBA-15

    DEFF Research Database (Denmark)

    Ikemoto, Hediki; Chi, Qijin; Ulstrup, Jens

    2010-01-01

    We have synthesized nanoporous silica, SBA-15 in the 1 m size range with the pore diameter of 7.6 nm. The redox enzyme horseradish peroxidase (HRP) was entrapped in the pores to form nanostructured hybrid materials. The catalytic activity of free and immobilized enzyme was first compared at room...... likely due to different hydrogen bonding of water and increased hydration strength of the protein inside the nanopores....

  1. Effect of support on the catalytic activity of manganese oxide catalyts for toluene combustion

    International Nuclear Information System (INIS)

    Pozan, Gulin Selda

    2012-01-01

    Highlights: ► α-Al 2 O 3 , obtained from Bohmite, as a support for enhancing of the activity. ► The support material for catalytic oxidation. ► The manganese state and oxygen species effect on the catalytic combustion reaction. - Abstract: The aim of this work was to study combustion of toluene (1000 ppm) over MnO 2 modified with different supports. α-Al 2 O 3 and γ-Al 2 O 3 obtained from Boehmite, γ-Al 2 O 3 (commercial), SiO 2 , TiO 2 and ZrO 2 were used as commercial support materials. In view of potential interest of this process, the influence of support material on the catalytic performance was discussed. The deposition of 9.5MnO 2 was performed by impregnation over support. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction and oxidation (TPR/TPO) and thermogravimetric analysis (TGA). The catalytic tests were carried out at atmospheric pressure in a fixed-bed flow reactor. 9.5MnO 2 /α-Al 2 O 3 (B) (synthesized from Boehmite) catalyst exhibits the highest catalytic activity, over which the toluene conversion was up to 90% at a temperature of 289 °C. Considering all the characterization and reaction data reported in this study, it was concluded that the manganese state and oxygen species played an important role in the catalytic activity.

  2. Hydrogen removal from LWR containments by catalytic-coated thermal insulation elements (THINCAT)

    International Nuclear Information System (INIS)

    Fischer, K.; Broeckerhoff, P.; Ahlers, G.; Gustavsson, V.; Herranz, L.; Polo, J.; Dominguez, T.; Royl, P.

    2003-01-01

    In the THINCAT project, an alternative concept for hydrogen mitigation in a light water reactor (LWR) containment is being developed. Based on catalytic coated thermal insulation elements of the main coolant loop components, it could be considered either as an alternative to backfitting passive autocatalytic recombiner devices, or as a reinforcement of their preventive effect. The present paper summarises the results achieved at about project mid-term. Potential advantages of catalytic thermal insulation studied in the project are:-reduced risk of unintended ignition,;-no work space obstruction in the containment,;-no need for seismic qualification of additional equipment,;-improved start-up behaviour of recombination reaction. Efforts to develop a suitable catalytic layer resulted in the identification of a coating procedure that ensures high chemical reactivity and mechanical stability. Test samples for use in forthcoming experiments with this coating were produced. Models to predict the catalytic rates were developed, validated and applied in a safety analysis study. Results show that an overall hydrogen concentration reduction can be achieved which is comparable to the reduction obtained using conventional recombiners. Existing experimental information supports the argument of a reduced ignition risk

  3. 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

  4. Degradation of the ammonia wastewater in aqueous medium with ozone in combination with mesoporous TiO2 catalytic

    Science.gov (United States)

    Liu, Zhiwu; Qiu, Jianping; Zheng, Chaocan; Li, Liqing

    2017-03-01

    TiO2 mesoporous nanomaterials are now widely used in catalytic ozone technology. In this paper, the market P25 as precursor hydrothermal method to prepare TiO2 mesoporous materials, ozone catalyst material characterization by transmission electron microscopy, surface area analyzers, and X-ray diffraction technique and found that nanotubes, nanosheets, nanorods through characterization results, nano-particles of different morphology and anatase and rutile proportion of the ozone catalytic material can be controlled by the calcination temperature and the temperature of hot water to give, and with the hot water temperature and calcination temperature, the catalyst becomes small aperture size larger catalyst crystalline phase from anatase to rutile gradually shift. Catalytic materials have been prepared by the Joint ozone degradation of ammonia wastewater to evaluate mesoporous TiO2 nanomaterials ozone catalytic performance, the results showed that: ammonia wastewater removal efficiency of various catalytic materials relatively separate ozone and markets P25 effects are significantly improved, and TiO2 nanotubes cooperate with ozone degradation ammonia wastewater highest efficiency, in addition, rutile TiO2 catalysts, the more the better the performance of their ozone catalysis.

  5. Effect of phase interaction on catalytic CO oxidation over the SnO_2/Al_2O_3 model catalyst

    International Nuclear Information System (INIS)

    Chai, Shujing; Bai, Xueqin; Li, Jing; Liu, Cheng; Ding, Tong; Tian, Ye; Liu, Chang; Xian, Hui; Mi, Wenbo; Li, Xingang

    2017-01-01

    Highlights: • Activity for CO oxidation is greatly enhanced by interaction between SnO_2 and Al_2O_3. • Interaction between SnO_2 and Al_2O_3 phases can generate oxygen vacancies. • Oxygen vacancies play an import role for catalytic CO oxidation. • Sn"4"+ cations are the effective sites for catalytic CO oxidation. • Langmuir-Hinshelwood model is preferred for catalytic CO oxidation. - Abstract: We investigated the catalytic CO oxidation over the SnO_2/Al_2O_3 model catalysts. Our results show that interaction between the Al_2O_3 and SnO_2 phases results in the significantly improved catalytic activity because of the formation of the oxygen vacancies. The oxygen storage capacity of the SnO_2/Al_2O_3 catalyst prepared by the physically mixed method is nearly two times higher than that of the SnO_2, which probably results from the change of electron concentration on the interface of the SnO_2 and Al_2O_3 phases. Introducing water vapor to the feeding gas would a little decrease the activity of the catalysts, but the reaction rate could completely recover after removal of water vapor. The kinetics results suggest that the surface Sn"4"+ cations are effective CO adsorptive sites, and the surface adsorbed oxygen plays an important role upon CO oxidation. The reaction pathways upon the SnO_2-based catalysts for CO oxidation follow the Langmuir-Hinshelwood model.

  6. 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Catalytic cracking models developed for predictive control purposes

    Directory of Open Access Journals (Sweden)

    Dag Ljungqvist

    1993-04-01

    Full Text Available The paper deals with state-space modeling issues in the context of model-predictive control, with application to catalytic cracking. Emphasis is placed on model establishment, verification and online adjustment. Both the Fluid Catalytic Cracking (FCC and the Residual Catalytic Cracking (RCC units are discussed. Catalytic cracking units involve complex interactive processes which are difficult to operate and control in an economically optimal way. The strong nonlinearities of the FCC process mean that the control calculation should be based on a nonlinear model with the relevant constraints included. However, the model can be simple compared to the complexity of the catalytic cracking plant. Model validity is ensured by a robust online model adjustment strategy. Model-predictive control schemes based on linear convolution models have been successfully applied to the supervisory dynamic control of catalytic cracking units, and the control can be further improved by the SSPC scheme.

  8. 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.

  9. Protein structure based prediction of catalytic residues.

    Science.gov (United States)

    Fajardo, J Eduardo; Fiser, Andras

    2013-02-22

    Worldwide structural genomics projects continue to release new protein structures at an unprecedented pace, so far nearly 6000, but only about 60% of these proteins have any sort of functional annotation. We explored a range of features that can be used for the prediction of functional residues given a known three-dimensional structure. These features include various centrality measures of nodes in graphs of interacting residues: closeness, betweenness and page-rank centrality. We also analyzed the distance of functional amino acids to the general center of mass (GCM) of the structure, relative solvent accessibility (RSA), and the use of relative entropy as a measure of sequence conservation. From the selected features, neural networks were trained to identify catalytic residues. We found that using distance to the GCM together with amino acid type provide a good discriminant function, when combined independently with sequence conservation. Using an independent test set of 29 annotated protein structures, the method returned 411 of the initial 9262 residues as the most likely to be involved in function. The output 411 residues contain 70 of the annotated 111 catalytic residues. This represents an approximately 14-fold enrichment of catalytic residues on the entire input set (corresponding to a sensitivity of 63% and a precision of 17%), a performance competitive with that of other state-of-the-art methods. We found that several of the graph based measures utilize the same underlying feature of protein structures, which can be simply and more effectively captured with the distance to GCM definition. This also has the added the advantage of simplicity and easy implementation. Meanwhile sequence conservation remains by far the most influential feature in identifying functional residues. We also found that due the rapid changes in size and composition of sequence databases, conservation calculations must be recalibrated for specific reference databases.

  10. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

    2013-01-01

    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  11. Tritium stripping by a catalytic exchange stripper

    International Nuclear Information System (INIS)

    Heung, L.K.; Gibson, G.W.; Ortman, M.S.

    1991-01-01

    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

  12. Plasma-catalytic reforming of liquid hydrocarbons

    International Nuclear Information System (INIS)

    Nedybaliuk, O.A.; Chernyak, V.Ya; Kolgan, V.V.; Iukhymenko, V.V.; Solomenko, O.V.; Fedirchyk, I.I.; Martysh, E.V.; Demchina, V.P.; Klochok, N.V.; Dragnev, S.V.

    2015-01-01

    The series of experiments studying the plasma-catalytic reforming of liquid hydrocarbons was carried out. The dynamic plasma-liquid system based on a low-power rotating gliding arc with solid electrodes was used for the investigation of liquid hydrocarbons reforming process. Conversion was done via partial oxidation. A part of oxidant flow was activated by the discharge. Synthesis-gas composition was analysed by means of mass-spectrometry and gas-chromatography. A standard boiler, which operates on natural gas and LPG, was used for the burning of synthesis-gas

  13. Methane combustion in catalytic premixed burners

    International Nuclear Information System (INIS)

    Cerri, I.; Saracco, G.; Specchia, V.

    1999-01-01

    Catalytic premixed burners for domestic boiler applications were developed with the aim of achieving a power modularity from 10 to 100% and pollutant emissions limited to NO x 2 , where the combustion took place entirely inside the burner heating it to incandescence and allowing a decrease in the flame temperature and NO x emissions. Such results were confirmed through further tests carried out in a commercial industrial-scale boiler equipped with the conical panels. All the results, by varying the excess air and the heat power employed, are presented and discussed [it

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

    Science.gov (United States)

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

    2018-01-01

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

  15. 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 differ...... different approximations are investigated: site, mean-field, and quasichemical approximations. The obtained results are compared to accurate Monte Carlo numbers. In the end, we apply the approximations to a real catalytic reaction, namely, ammonia synthesis....

  16. A study on naphtha catalytic reforming reactor simulation and analysis.

    Science.gov (United States)

    Liang, Ke-min; Guo, Hai-yan; Pan, Shi-wei

    2005-06-01

    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.

  17. A study on naphtha catalytic reforming reactor simulation and analysis

    OpenAIRE

    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 uni...

  18. Effect of support on the catalytic activity of manganese oxide catalyts for toluene combustion.

    Science.gov (United States)

    Pozan, Gulin Selda

    2012-06-30

    The aim of this work was to study combustion of toluene (1000ppm) over MnO(2) modified with different supports. α-Al(2)O(3) and γ-Al(2)O(3) obtained from Boehmite, γ-Al(2)O(3) (commercial), SiO(2), TiO(2) and ZrO(2) were used as commercial support materials. In view of potential interest of this process, the influence of support material on the catalytic performance was discussed. The deposition of 9.5MnO(2) was performed by impregnation over support. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction and oxidation (TPR/TPO) and thermogravimetric analysis (TGA). The catalytic tests were carried out at atmospheric pressure in a fixed-bed flow reactor. 9.5MnO(2)/α-Al(2)O(3)(B) (synthesized from Boehmite) catalyst exhibits the highest catalytic activity, over which the toluene conversion was up to 90% at a temperature of 289°C. Considering all the characterization and reaction data reported in this study, it was concluded that the manganese state and oxygen species played an important role in the catalytic activity. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Non-thermal plasmas for non-catalytic and catalytic VOC abatement

    International Nuclear Information System (INIS)

    Vandenbroucke, Arne M.; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

    2011-01-01

    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.

  20. Microwave Catalytic Oxidation of Hydrocarbons in Aqueous Solutions

    National Research Council Canada - National Science Library

    Cha, Chang

    2003-01-01

    .... A sufficient amount of experimental work has been completed evaluating the performance of the microwave catalytic oxidation process and determining the effect of different operating parameters...

  1. 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.

  2. Validation of the catalytic properties of Cu-Os/13X using single fixed bed reactor in selective catalytic reduction of NO

    International Nuclear Information System (INIS)

    Oh, Kwang Seok; Woo, Seong Ihl

    2007-01-01

    Catalytic decomposition of NO over Cu-Os/13X has been carried out in a tubular fixed bed reactor at atmospheric pressure and the results were compared with literature data performed by high-throughput screening (HTS). The activity and durability of Cu-Os/13X prepared by conventional ion-exchange method have been investigated in the presence of H 2 O and SO 2 . It was found that Cu-Os/13X prepared by ion-exchange shows a high activity in a wide temperature range in selective catalytic reduction (SCR) of NO with C 3 H 6 compared to Cu/13X, proving the existence of more NO adsorption site on Cu-Os/13X. However, Cu-Os/13X exhibited low activity in the presence of water, and was quite different from the result reported in literature. SO 2 resistance is also low and does not recover its original activity when the SO 2 was blocked in the feed gas stream. This result suggested that catalytic activity between combinatorial screening and conventional testing should be compared to confirm the validity of high-throughput screening

  3. Catalytic molecularly imprinted polymer membranes: development of the biomimetic sensor for phenols detection.

    Science.gov (United States)

    Sergeyeva, T A; Slinchenko, O A; Gorbach, L A; Matyushov, V F; Brovko, O O; Piletsky, S A; Sergeeva, L M; Elska, G V

    2010-02-05

    Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu(II)-catechol-urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes' structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers-biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063-1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols

  4. 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.

  5. Catalytic Properties of Lipase Extracts from Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Cintia M. Romero

    2006-01-01

    Full Text Available Screening of lipolytic strains using Rhodamine-B/olive oil plate technique allowed the selection of Aspergillus niger MYA 135. Lipase production in submerged culture containing 2 % olive oil was enhanced by more than 50 % compared to basal cultural conditions. Optimal catalytic conditions for olive oil-induced lipase were pH=6.5 and 30–35 °C. These values were shifted to the acid region (4.0–6.5 and 35–37 °C when lipase extract was produced under basal conditions. Slight changes of the residual lipase activity against the pH were found. However, preincubation at either 37 or 40 °C caused an increase in the olive oil-inducible lipolytic activity. On the contrary, lipase residual activity decreases in the 30–55 °C range when it was produced in basal medium. Lipolytic extracts were almost not deactivated in presence of 50 % water-miscible organic solvents. However, water-immiscible aliphatic solvents reduced the lipase activity between 20 and 80 %.

  6. Catalytic hydrogenation of carbonyl group for deuterated compound production

    International Nuclear Information System (INIS)

    Gluhoi, C. Andreea; Marginean, P.; Lazar, Diana; Almasan, V.

    1999-01-01

    The total deuterated isopropyl alcohol can be produced starting from acetone. The developed technology comprises two steps: Deuteration of acetone by H/D isotopic exchange between acetone and heavy water in homogeneous catalysis. Reduction of the deuterated acetone with deuterium in presence of a metal/support catalyst. H/D isotopic exchange reaction of the H atoms from CH 3 groups is easy to occur because carbonyl group weakens C-H bond (ceto-enolyc tautomery). The big difference between boiling points of acetone and water permits an easy separation of acetone by distillation method. The reduction of acetone with deuterium was performed in a dynamic reactor by passing a deuterium flow saturated with acetone vapour through a supported nickel catalyst bed. The reaction products were analysed on-line using a flame ionisation detector. The supported nickel catalysts were checked for this reaction. By using nickel over different supports the selectivity for isopropyl alcohol was about 100%. The propane was detected only as traces. The catalytic activity depends strongly on the support nature: the Ni/SiO 2 is less active, while the Ni/TiO 2 presents the larger value for the intrinsic activity. (authors)

  7. SAFIRA project B.3.3: in-situ-treatment of contaminated ground water by catalytic oxidation. Final report; Sanierungsforschung in regional kontaminierten Aquiferen (SAFIRA). Projekt B.3.3: In situ-Behandlung von kontaminierten Grundwaessern durch katalytische Oxidation. Teilvorhaben 1: Untersuchungen im Labormassstab. Teilvorhaben 2: Tests in der bench-scale-Anlage und Teilvorhaben 3: Die Erprobung in der Pilotanlage am Modellstandort. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, J.; Haentzschel, D.; Freier, U.; Wecks, M.

    2003-06-27

    A new technology for treatment of contaminated ground water was developed. In this process heterogeneous catalysts (full metal catalyst, mixed oxide catalyst or iron-containing zeolites) in combination with hydrogen peroxide are used. In the reactor catalytic oxidation and aerob biological degradation occur simultaneously. A complete degradation of chlorobenzene was observed in a bench-scale-equipment (2 liter) and also in the pilot plant at the model site located in Bitterfeld (30 liter reactor). The technology can be applied to the ground and waste water treatment. (orig.) [German] Fuer die Behandlung von Grundwaessern, die mit organischen Schadstoffen belastet sind, wurde ein neuartiges Verfahren entwickelt. Bei der katalytischen Oxidation werden heterogene Katalysatoren in Form von Vollmetall-, Mischoxid- und Traegerkatalysatoren in Verbindung mit Wasserstoffperoxid als Oxidationsmittel eingesetzt. In den Katalysereaktoren laufen die heterogen-katalytische Oxidation und der aerob-biologische Abbau nebeneinander ab. Es werden synergistische Effekte erzielt. Mit dem Verfahren wurde in einer bench-scale-Angle (2 Liter) und in der Pilotanlage am Modellstandort in Bitterfeld (30 l Reaktor) der Schadstoff Chlorbenzol vollstaendig umgesetzt. Das Verfahren kann zur Grund- und Abwasserbehandlung eingesetzt werden. (orig.)

  8. Destruction of organochlorated compounds and CFCs by catalytic hydrodechloration; Destruccion de compuestos organoclorados y CFCs mediante hidrodecloracion catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez Garcia, S.; Sastre Andres, H.; Diez Sanz, F. V.

    1998-12-01

    The destruction of organohalogenated compounds ( for example chlorinated solvents, PCBs and CFCs) is a very serious environmental problems. Catalytic hydrodechlorination has shown to be potentially efficient method for the destruction of these compounds. In this technique the halogenated compound reacts with hydrogen, tielding a non-chlorinated compound (environmentally harmless) and hydrogen-chloride. In this article, different set-ups and catalysts employed in the catalytic hydrogechlorination were described. Finally, some applications of this technique to the treatment of industrial effluents, such as the destruction of chlorinated solvents (as trichloroethylene o tetrachloromethane), conversion of CFCs into HCFCs, destruction of PCBs and treatment of water polluted with chlorinated pesticides. (Author) 28 refs.

  9. 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.

  10. New separation technique. Catalytically functionated separation membrane

    Energy Technology Data Exchange (ETDEWEB)

    Urgami, Tadashi [Kansai Univ., Osaka (Japan)

    1989-02-01

    This report introduces research examples, showing the fundamental principle of the membrane by separating the catalytically functionated separation membrane into enzyme fixing separation membrane, polymerized metal complex separation membrane and polymer catalyst separation membrane. This membrane can achieve both functions of separation and catalytic reaction simultaneously and has sufficient possibility to combine powerful functions. Enzyme fixing separation membrane is prepared by carrier combination method, bridging method or covering method and the enzyme fixing method with polymerized complex in which enzyme is controlled to prevent the activity lowering as much as possible and enzyme is fixed from an aqueous solution into polymer membrane. This membrane is applied to the continuous manufacturing of invert sugar from cane sugar and adsorption and removing of harmful substances from blood by utilizing both micro-capsuled urease and active carbon. Alginic acid-copper (II) complex membrane is used for the polymerized metal complex membrane and polystyrene sulfonate membrane is used for the polymer catalyst separation membrane. 28 refs., 4 figs., 1 tabs.

  11. Catalytic hydroprocessing of heavy oil feedstocks

    International Nuclear Information System (INIS)

    Okunev, A G; Parkhomchuk, E V; Lysikov, A I; Parunin, P D; Semeikina, V S; Parmon, V N

    2015-01-01

    A grave problem of modern oil refining industry is continuous deterioration of the produced oil quality, on the one hand, and increase in the demand for motor fuels, on the other hand. This necessitates processing of heavy oil feedstock with high contents of sulfur, nitrogen and metals and the atmospheric residue. This feedstock is converted to light oil products via hydrogenation processes catalyzed by transition metal compounds, first of all, cobalt- or nickel-promoted molybdenum and tungsten compounds. The processing involves desulfurization, denitrogenation and demetallization reactions as well as reactions converting heavy hydrocarbons to lighter fuel components. The review discusses the mechanisms of reactions involved in the heavy feedstock hydroprocessing, the presumed structure and state of the catalytically active components and methods for the formation of supports with the desired texture. Practically used and prospective approaches to catalytic upgrading of heavy oil feedstock as well as examples of industrial processing of bitumen and vacuum residues in the presence of catalysts are briefly discussed. The bibliography includes 140 references

  12. Catalytic hydroprocessing of heavy oil feedstocks

    Science.gov (United States)

    Okunev, A. G.; Parkhomchuk, E. V.; Lysikov, A. I.; Parunin, P. D.; Semeikina, V. S.; Parmon, V. N.

    2015-09-01

    A grave problem of modern oil refining industry is continuous deterioration of the produced oil quality, on the one hand, and increase in the demand for motor fuels, on the other hand. This necessitates processing of heavy oil feedstock with high contents of sulfur, nitrogen and metals and the atmospheric residue. This feedstock is converted to light oil products via hydrogenation processes catalyzed by transition metal compounds, first of all, cobalt- or nickel-promoted molybdenum and tungsten compounds. The processing involves desulfurization, denitrogenation and demetallization reactions as well as reactions converting heavy hydrocarbons to lighter fuel components. The review discusses the mechanisms of reactions involved in the heavy feedstock hydroprocessing, the presumed structure and state of the catalytically active components and methods for the formation of supports with the desired texture. Practically used and prospective approaches to catalytic upgrading of heavy oil feedstock as well as examples of industrial processing of bitumen and vacuum residues in the presence of catalysts are briefly discussed. The bibliography includes 140 references.

  13. 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.

  14. Structured materials for catalytic and sensing applications

    Science.gov (United States)

    Hokenek, Selma

    The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts is, therefore, an attractive option. Similarly, the optical properties of nanoscale materials used for sensing must be attuned to their application. By adjusting the shape and composition of nanoparticles used in such applications, very fine changes can be made to the frequency of light that they absorb most efficiently. The design, synthesis, and characterization of (i) size controlled monometallic palladium nanoparticles for catalytic applications, (ii) nickel-palladium bimetallic nanoparticles and (iii) silver-palladium nanoparticles with applications in drug detection and biosensing through surface plasmon resonance, respectively, will be discussed. The composition, size, and shape of the nanoparticles formed were controlled through the use of wet chemistry techniques. After synthesis, the nanoparticles were analyzed using physical and chemical characterization techniques such as X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy- Energy-Dispersive Spectrometry (STEM-EDX). The Pd and Ni-Pd nanoparticles were then supported on silica for catalytic testing using mass spectrometry. The optical properties of the Ag-Pd nanoparticles in suspension were further investigated using ultraviolet-visible spectrometry (UV-Vis). Monometallic palladium particles have

  15. 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

  16. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    Science.gov (United States)

    Islam, A. E.; Nikolaev, P.; Amama, P. B.; Zakharov, D.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; Stach, E. A.; Maruyama, B.

    2015-09-01

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only in the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. With the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.

  17. Catalytic conversion of corncob and corncob pretreatment hydrolysate to furfural in a biphasic system with addition of sodium chloride.

    Science.gov (United States)

    Qing, Qing; Guo, Qi; Zhou, Linlin; Wan, Yilun; Xu, Youqing; Ji, Huilong; Gao, Xiaohang; Zhang, Yue

    2017-02-01

    Catalytic conversion of corncob pretreatment hydrolysate and raw corncob into furfural in a modified biphasic system by SO 4 2- /SnO 2 - MMT solid catalyst has been developed. The influence of the organic solvent type, organic to water phase ratio, sodium chloride concentration, reaction temperature and time on the furfural production were comparatively evaluated. The results showed that furfural yields of 81.7% and 66.1% were achieved at 190°C for 15mins and 190°C for 20mins, respectively, for corncob pretreatment hydrolysate and raw corncob by this solid catalyst. The solid catalyst used in this study exhibited good stability and high efficiency applied in the modified biphasic system in addition to excellent recyclability. The proposed catalytic system displayed high performance for catalytic conversion of lignocellulosic biomass into important platform chemicals and has great potential in industrial application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Fractional Multistage Hydrothermal Liquefaction of Biomass and Catalytic Conversion into Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cortright, Randy [Virent, Inc., Madison, WI (United States); Rozmiarek, Robert [Virent, Inc., Madison, WI (United States); Dally, Brice [Virent, Inc., Madison, WI (United States); Holland, Chris [Virent, Inc., Madison, WI (United States)

    2017-08-31

    The objective of this project was to develop an improved multistage process for the hydrothermal liquefaction (HTL) of biomass to serve as a new front-end, deconstruction process ideally suited to feed Virent’s well-proven catalytic technology, which is already being scaled up. This process produced water soluble, partially de-oxygenated intermediates that are ideally suited for catalytic finishing to fungible distillate hydrocarbons. Through this project, Virent, with its partners, demonstrated the conversion of pine wood chips to drop-in hydrocarbon distillate fuels using a multi-stage fractional conversion system that is integrated with Virent’s BioForming® process. The majority of work was in the liquefaction task and included temperature scoping, solvent optimization, and separations.

  19. Catalytic activity of supported silver and potassium salts of tungstophosphoric acid in dehydration of ethanol

    International Nuclear Information System (INIS)

    Haber, J.; Matachowski, L.; Pamin, K.; Napruszewska, B.

    2002-01-01

    Potassium and silver salts of tungstophosphoric acid (HPW) have been supported on silica. Two series of potassium and silver salts of tungstophosphoric acid K x H 3-x PW 12 O 40 and Ag x H 3-x PW 12 O 40 where x = 1;2;3 supported on silica were prepared using incipient wetness method. In a typical synthesis, the heteropolyacid which after deposition on silica was washed with water to remove the part of heteropolyacid not bound to the support was reacted with silver or potassium salt. The vapor-phase dehydration of ethanol was employed as a test reaction. All the catalytic tests were carried out in a conventional flow type reactor, under atmospheric pressure, in the temperature range 125-500 o C. The results of these studies were used to explain the differences between the catalytic activities of heteropolysalts of potassium and silver supported on silica. (author)

  20. Improving the engine power of a catalytic Janus-sphere micromotor by roughening its surface.

    Science.gov (United States)

    Longbottom, Brooke W; Bon, Stefan A F

    2018-03-15

    Microspheres with catalytic caps have become a popular model system for studying self-propelled colloids. Existing experimental studies involve predominantly "smooth" particle surfaces. In this study we determine the effect of irregular surface deformations on the propulsive mechanism with a particular focus on speed. The particle surfaces of polymer microspheres were deformed prior to depositing a layer of platinum which resulted in the formation of nanoscopic pillars of catalyst. Self-propulsion was induced upon exposure of the micromotors to hydrogen peroxide, whilst they were dispersed in water. The topological surface features were shown to boost speed (~2×) when the underlying deformations are small (nanoscale), whilst large deformations afforded little difference despite a substantial apparent catalytic surface area. Colloids with deformed surfaces were more likely to display a mixture of rotational and translational propulsion than their "smooth" counterparts.

  1. 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...

  2. 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.

  3. Selective catalytic reduction of nitrogen oxides from industrial gases by hydrogen or methane

    International Nuclear Information System (INIS)

    Engelmann Pirez, M.

    2004-12-01

    This work deals with the selective catalytic reduction of nitrogen oxides (NO x ), 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 N 2 , in presence of an excess of oxygen, steam and sulfur dioxide. The developed catalyst is constituted by a support such as perovskites, particularly LaCoO 3 , 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.)

  4. Selective catalytic reduction of nitric oxide by ammonia over Cu-exchanged Cuban natural zeolites

    International Nuclear Information System (INIS)

    Moreno-Tost, Ramon; Santamaria-Gonzalez, Jose; Rodriguez-Castellon, Enrique; Jimenez-Lopez, Antonio; Autie, Miguel A.; Glacial, Marisol Carreras; Gonzalez, Edel; Pozas, Carlos De las

    2004-01-01

    The catalytic selective reduction of NO over Cu-exchanged natural zeolites (mordenite (MP) and clinoptilolite (HC)) from Cuba using NH 3 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 N 2 at low temperatures, and exhibiting good water tolerance. The chemical state of the Cu(II) in exchanged zeolites was characterized by H 2 -TPR and XPS. Cu(II)-exchanged clinoptilolite underwent a severe deactivation in the presence of SO 2 . 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 SO 2

  5. Pt@Ag and Pd@Ag core/shell nanoparticles for catalytic degradation of Congo red in aqueous solution

    Science.gov (United States)

    Salem, Mohamed A.; Bakr, Eman A.; El-Attar, Heba G.

    2018-01-01

    Platinum/silver (Pt@Ag) and palladium/silver (Pd@Ag) core/shell NPs have been synthesized in two steps reaction using the citrate method. The progress of nanoparticle formation was followed by the UV/Vis spectroscopy. Transmission electron microscopy revealed spherical shaped core/shell nanoparticles with average particle diameter 32.17 nm for Pt@Ag and 8.8 nm for Pd@Ag. The core/shell NPs were further characterized by FT-IR and XRD. Reductive degradation of the Congo red dye was chosen to demonstrate the excellent catalytic activity of these core/shell nanostructures. The nanocatalysts act as electron mediators for the transfer of electrons from the reducing agent (NaBH4) to the dye molecules. Effect of reaction parameters such as nanocatalyst dose, dye and NaBH4 concentrations on the dye degradation was investigated. A comparison between the catalytic activities of both nanocatalysts was made to realize which of them the best in catalytic performance. Pd@Ag was the higher in catalytic activity over Pt@Ag. Such greater activity is originated from the smaller particle size and larger surface area. Pd@Ag nanocatalyst was catalytically stable through four subsequent reaction runs under the utilized reaction conditions. These findings can thus be considered as possible economical alternative for environmental safety against water pollution by dyes.

  6. Development of a water detritiation facility for JET

    International Nuclear Information System (INIS)

    Perevezentsev, A.N.; Bell, A.C.; Brennan, P.D.; Hemmerich, J.L.

    2002-01-01

    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

  7. Hydrogen Production From catalytic reforming of greenhouse gases ...

    African Journals Online (AJOL)

    ADOWIE PERE

    a fixed bed stainless steel reactor. The 20wt%. ... catalytic activity for hydrogen production with the highest yield and selectivity of 32.5% and 17.6% respectively. © JASEM ... CO2 reforming of methane is however not fully developed ..... Design and preparation of .... catalytic nickel membrane for gas to liquid (GTL) process.

  8. Catalytic synthesis of ammonia using vibrationally excited nitrogen molecules

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Henriksen, Niels Engholm; Billing, Gert D.

    1992-01-01

    The dissociation of nitrogen is the rate-limiting step in the catalytic synthesis of ammonia. Theoretical calculations have shown that the dissociative sticking probability of molecular nitrogen on catalytic active metal surfaces is enhanced by orders of magnitude when the molecules...

  9. synthesis, characterization, electrical and catalytic studies of some

    African Journals Online (AJOL)

    B. S. Chandravanshi

    catalytic activity of the VO(IV) and Mn(III) complexes have been tested in the epoxidation reaction of styrene ... Vanadyl sulfate pentahydrate, chromium chloride hexahydrate, anhydrous ferric ..... The catalytic oxidation of styrene gives the products styrene oxide, benzaldehyde, benzoic acid, ... bond via a radical mechanism.

  10. Catalytic performance of heterogeneous Rh/C3N4 for the carbonylation of methanol

    Science.gov (United States)

    Budiman, Anatta Wahyu; Choi, Myoung Jae; Nur, Adrian

    2018-02-01

    The excess of water in homogeneous the carbonylation of methanol system could increase the amount of by-products formed through water-gas shift reaction and could accelerate the rusting of equipment. Many scientists tried to decrease the content of water in the carbonylation of methanol system by using lithium and iodide promoter that results a moderate catalytic activity in the water content at 2wt%. The heterogenized catalyst offers several distinct advantages such as it was enables increased catalyst concentration in the reaction mixture, which is directly proportional to acetic acid production rate, without the addition of an alkali iodide salt promoter. The heterogeneous catalyst also results in reduced by-product formation. This study is aimed to produce a novel catalyst (Rh/C3N4) with a high selectivity of acetic acid in a relatively lower water and halide content. This novel catalyst performs high conversion and selectivity of acetic acid as the result of the strong ionic bonding of melamine and rhodium complex species that was caused by the presence of methyl iodide species. The CO2 in feed gas significantly decreases the catalytic activity of Rh-melamine because of its inert characteristics. The kinetic test was performed as that the first order kinetic equation. The kinetic tests revealed the reaction route of the the carbonylation of methanol in this system was performed trough the methyl acetate.

  11. 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.

  12. Carbon nanofibers: a versatile catalytic support

    Directory of Open Access Journals (Sweden)

    Nelize Maria de Almeida Coelho

    2008-09-01

    Full Text Available The aim of this article is present an overview of the promising results obtained while using carbon nanofibers based composites as catalyst support for different practical applications: hydrazine decomposition, styrene synthesis, direct oxidation of H2S into elementary sulfur and as fuel-cell electrodes. We have also discussed some prospects of the use of these new materials in total combustion of methane and in ammonia decomposition. The macroscopic carbon nanofibers based composites were prepared by the CVD method (Carbon Vapor Deposition employing a gaseous mixture of hydrogen and ethane. The results showed a high catalytic activity and selectivity in comparison to the traditional catalysts employed in these reactions. The fact was attributed, mainly, to the morphology and the high external surface of the catalyst support.

  13. Radiant non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.

    2017-10-31

    A radiant, non-catalytic recuperative reformer has a flue gas flow path for conducting hot exhaust 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 positioned adjacent to the flue gas flow path to permit heat transfer from the hot exhaust 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, a portion of the reforming mixture flow path is positioned outside of flue gas flow path for a relatively large residence time.

  14. Chemical and catalytic effects of ion implantation

    International Nuclear Information System (INIS)

    Wolf, G.K.

    1982-01-01

    Energetic particles are used for inducing chemical reactions as well as for modifying the properties of materials with regard to their bulk and surface chemical behavior. The effects are partly caused by radiation damage or phase intermixing, partly by the chemical properties of the individual bombarding particles. In this contribution a survey of relevant applications of these techniques is presented: (1) Chemical reactions of implanted and recoil atoms and their use for syntheses, doping and labeling of compounds. (2) The formation of thin films by decomposing chemical compounds with ion beams. 3) Catalytic effects on substrates treated by sputtering or ion implantation. Recent results with nonmetallic substrates are reviewed. Mainly hydrogenation reactions at a solid/gas interface or redox reactions at an electrified solid/liquid interface are mentioned. The present status and future prospects of these kinds of investigations will be discussed. (author)

  15. Contact structure for use in catalytic distillation

    Science.gov (United States)

    Jones, E.M. Jr.

    1984-03-27

    A method is described for conducting catalytic chemical reactions and fractionation of the reaction mixture comprising feeding reactants into a distillation column reactor, contracting said reactant in liquid phase with a fixed bed catalyst in the form of a contact catalyst structure consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

  16. Direct catalytic asymmetric aldol-Tishchenko reaction.

    Science.gov (United States)

    Gnanadesikan, Vijay; Horiuchi, Yoshihiro; Ohshima, Takashi; Shibasaki, Masakatsu

    2004-06-30

    A direct catalytic asymmetric aldol reaction of propionate equivalent was achieved via the aldol-Tishchenko reaction. Coupling an irreversible Tishchenko reaction to a reversible aldol reaction overcame the retro-aldol reaction problem and thereby afforded the products in high enantio and diastereoselectivity using 10 mol % of the asymmetric catalyst. A variety of ketones and aldehydes, including propyl and butyl ketones, were coupled efficiently, yielding the corresponding aldol-Tishchenko products in up to 96% yield and 95% ee. Diastereoselectivity was generally below the detection limit of 1H NMR (>98:2). Preliminary studies performed to clarify the mechanism revealed that the aldol products were racemic with no diastereoselectivity. On the other hand, the Tishchenko products were obtained in a highly enantiocontrolled manner.

  17. Smoke emissions from a catalytic wood stove

    International Nuclear Information System (INIS)

    Cowburn, D.A.; Stephens, N.P.J.

    1994-01-01

    The work reported here was concerned with testing a catalytic wood burning stove (roomheater) following the most applicable UK procedures. The identical stove has also been tested in several other nations to their individual procedures. The results will be submitted to the International Energy Agency (IEA) such that appropriate comparisons can be made. The results comprised: burning rate; an indicative appliance efficiency; heat output; carbon dioxide emissions; carbon monoxide emissions; and smoke emissions. These results were determined with the appliance at three nominal burning rates (high, medium and low). Comparing the results with those obtained in other countries indicates good agreement except when the appliance was operated at low burning rates, under which conditions the UK results indicate significantly worse smoke emissions than those measured by other researchers. (author)

  18. Flowthrough Reductive Catalytic Fractionation of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Eric M.; Stone, Michael L.; Katahira, Rui; Reed, Michelle; Beckham, Gregg T.; Román-Leshkov, Yuriy

    2017-11-01

    Reductive catalytic fractionation (RCF) has emerged as a leading biomass fractionation and lignin valorization strategy. Here, flowthrough reactors were used to investigate RCF of poplar. Most RCF studies to date have been conducted in batch, but a flow-based process enables the acquisition of intrinsic kinetic and mechanistic data essential to accelerate the design, optimization, and scale-up of RCF processes. Time-resolved product distributions and yields obtained from experiments with different catalyst loadings were used to identify and deconvolute events during solvolysis and hydrogenolysis. Multi-bed RCF experiments provided unique insights into catalyst deactivation, showing that leaching, sintering, and surface poisoning are causes for decreased catalyst performance. The onset of catalyst deactivation resulted in higher concentrations of unsaturated lignin intermediates and increased occurrence of repolymerization reactions, producing high-molecular-weight species. Overall, this study demonstrates the concept of flowthrough RCF, which will be vital for realistic scale-up of this promising approach.

  19. Propulsion Mechanism of Catalytic Microjet Engines.

    Science.gov (United States)

    Fomin, Vladimir M; Hippler, Markus; Magdanz, Veronika; Soler, Lluís; Sanchez, Samuel; Schmidt, Oliver G

    2014-02-01

    We describe the propulsion mechanism of the catalytic microjet engines that are fabricated using rolled-up nanotech. Microjets have recently shown numerous potential applications in nanorobotics but currently there is a lack of an accurate theoretical model that describes the origin of the motion as well as the mechanism of self-propulsion. The geometric asymmetry of a tubular microjet leads to the development of a capillary force, which tends to propel a bubble toward the larger opening of the tube. Because of this motion in an asymmetric tube, there emerges a momentum transfer to the fluid. In order to compensate this momentum transfer, a jet force acting on the tube occurs. This force, which is counterbalanced by the linear drag force, enables tube velocities of the order of 100 μ m/s. This mechanism provides a fundamental explanation for the development of driving forces that are acting on bubbles in tubular microjets.

  20. Catalytic Synthesis of Nitriles in Continuous Flow

    DEFF Research Database (Denmark)

    Nordvang, Emily Catherine

    The objective of this thesis is to report the development of a new, alternative process for the flexible production of nitrile compounds in continuous flow. Nitriles are an important class of compounds that find applications as solvents, chemical intermediates and pharmaceutical compounds......, alternative path to acetonitrile from ethanol via the oxidative dehydrogenation of ethylamine. The catalytic activity and product ratios of the batch and continuous flow reactions are compared and the effect of reaction conditions on the reaction is investigated. The effects of ammonia in the reaction...... dehydrogenation of ethylamine and post-reaction purging.Chapter 4 outlines the application of RuO2/Al2O3 catalysts to the oxidative dehydrogenation of benzylamine in air, utilizing a new reaction setup. Again, batch and continuous flow reactions are compared and the effects of reaction conditions, ammonia...