2,927 research outputs found

    Aquachlorido(2-{[6-(dimethylamino)pyrimidin-4- yl]sulfanyl}pyrimidine-4,6-diamine)copper(II) chloride hydrate

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    A copper(II) complex of the non-symmetric bidentate ligand 2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine (L1) is reported. The single-crystal X-ray structure of aqua­[aqua/chlorido­(0.49/0.51)](2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine)­copper(II) 0.49-chloride 1.51-hydrate, [CuCl1.51(C10H13N7S)(H2O)1.49]Cl0.49·1.51H2O or [(L1)Cl1.51(H2O)1.49Cu]0.49Cl·1.51H2O, exhibits distorted square-pyramidal geometry around the metal centre, with disorder in the axial position, occupied by chloride or water. The six-membered metal–chelate ring is in a boat conformation, and short inter­molecular S- - -S inter­actions are observed. In addition to its capacity for bidentate metal coordination, the ligand has the ability to engage in further supra­molecular inter­actions as both a hydrogen-bond donor and acceptor, and multiple inter­actions with lattice solvent water mol­ecules are present in the reported structure

    Noncommutative geometry, topology and the standard model vacuum

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    As a ramification of a motivational discussion for previous joint work, in which equations of motion for the finite spectral action of the Standard Model were derived, we provide a new analysis of the results of the calculations herein, switching from the perspective of Spectral triple to that of Fredholm module and thus from the analogy with Riemannian geometry to the pre-metrical structure of the Noncommutative geometry. Using a suggested Noncommutative version of Morse theory together with algebraic KK-theory to analyse the vacuum solutions, the first two summands of the algebra for the finite triple of the Standard Model arise up to Morita equivalence. We also demonstrate a new vacuum solution whose features are compatible with the physical mass matrix.Comment: 24 page

    Non-commutative geometry and the standard model vacuum

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    The space of Dirac operators for the Connes-Chamseddine spectral action for the standard model of particle physics coupled to gravity is studied. The model is extended by including right-handed neutrino states, and the S0-reality axiom is not assumed. The possibility of allowing more general fluctuations than the inner fluctuations of the vacuum is proposed. The maximal case of all possible fluctuations is studied by considering the equations of motion for the vacuum. Whilst there are interesting non-trivial vacua with Majorana-like mass terms for the leptons, the conclusion is that the equations are too restrictive to allow solutions with the standard model mass matrix.Comment: 21 pages. v2: some comments improve

    Peng-Robinson Equation of State Predictions for Gas Condensate Before and After Lumping

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    Gas condensate compositional simulation studies are conducted to evaluate gas and condensate reserves and make comparisons of production methods for the economic development of a reservoir. The data needed for the evaluation are dew point pressure, gas compressibility factor, liquid volume and produced gas. Hosein and Dawe showed that compositional analysis greater than Single Carbon Number 24 (SCN24) is required for accurate prediction of these data by a tuned Equation of State (EOS). However they did not demonstrate the accuracy of their tuning technique with lumped components which are applied when performing simulation studies to reduce cost and computer time involved.  Simple and complex schemes for lumping of the SCN groups into less than 6 Multiple Carbon Number (MCN) groups have been devised. However there are currently no criteria for selecting the best lumping scheme that will give similar accuracy to using many SCN groups except by trial and error, or by algorithms designed to test a number of schemes and to select the best one. In this paper we have used Whitson’s lumping scheme which is in the form of a simple mathematical expression in comparison to other lumping schemes from the open literature. The tuning technique of Hosein and Dawe was applied and differences of less than ±4.0 % from tuned EOS predictions before and after lumping of the SCN groups were obtained. These results indicate that the tuning technique of Hosein and Dawe could be used to perform accurate simulation studies of lean and rich gas condensate systems using MCN groups lumped by the Whitson’s lumping scheme. Complex algorithms are not necessary to select an appropriate lumping scheme.Key words: Gas condensate; Equation of state; Predictions; Single carbon number; Lumpin

    Évaluation de l’effet insecticide de l’extrait acétonique des feuilles séchées de Calotropis procera Ait. (Asclepiadaceae) chez les adultes de Anopheles gambiae, Maroua (Cameroun)

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    L’efficacité de l’extrait acétonique des feuilles de Calotropis procera a été évaluée sur les adultes de Anopheles gambiae de la ville de Maroua (Cameroun) par la méthode de la moustiquaire imprégnée. La poudre des feuilles de cette plante a été extraite à l’acétone et dilué à l’hexane à des concentrations suivantes : 8,45mg ; 23,35mg, 42,25mg ; 59,15mg et 84,5mg pour imprégner une surface de moustiquaire de 1,69 cm2. Les parcelles de moustiquaire imprégnées sont fixées à la base des cônes calqués sur le modèle des cônes-OMS. Après 24 heures d’exposition, nous avons obtenu 100% de mortalité des moustiques aux concentrations 59,15mg et 84,5mg. La concentration létale 50 (CL50) est de 3,03 g/m² et l’heure létale 50 (HL50) est de 7 h 31 min17s. Toutefois, ces valeurs de CL50 et HL50 sont très élevées comparativement à la Moustiquaire Imprégnée (MILDA) de l’Insecticide Deltaméthrine (55 mg/m2) qui est à Longue Durée d’Action et efficace à la CL50 de 2,30 x10-4 g/m2 et HL50 de 2h11mn13s. Ce qui signifie que la moustiquaire-MILDA est plus efficace que l’extrait des feuilles de Calotropis procera.Mots clés: Calotropis procera, effet insecticide, moustiquaire imprégnée, Anopheles gambiae, Maroua, Cameroun
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