Search results for "Mixed"
showing 10 items of 783 documents
Selective Surface Modification of SiO2−TiO2 Supports with Phosphonic Acids
2004
The selective surface modification by phosphonic acids of SiO2−TiO2 supports at the micrometer and molecular scale was investigated. Under aqueous conditions, phosphonic acids bind to TiO2 and not to SiO2 surfaces. A micropatterned support was prepared by electron beam microlithography and selectivity, of the surface modification was evidenced using scanning Auger electron spectroscopy (SAES). The second support was a mesoporous SiO2−TiO2 mixed oxide (10 mol % Ti) epoxidation catalyst prepared by sol−gel processing. Selectivity was deduced from the decrease of the catalytic activity upon modification and from chemical analysis; bonding modes to the surface were investigated using solid-stat…
Three-Dimensional Mixed-Ligand Coordination Polymers with Ferromagnetically Coupled Cyclic Tetranuclear Copper(II) Units Bonded by Weak Interactions
2011
The complexes {[Cu(HGLYO)(NO3)(bpy)]·H2O}4 (1), {[Cu(HGLYO)(NO3)(phen)]·H2O}4 (2), and [Cu(HLACO)(ClO4)(phen)]4 (3) (bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline, HGLYO is monoanionic glycol...
Structural evolution of Pt/ceria-zirconia TWC catalysts during the oxidation of carbon monoxide
2004
The structural evolution of two Pt/ceria–zirconia catalysts, characterized by different amounts of supported Pt, was monitored by in situ X-ray diffraction during the anaerobic oxidation of CO at different temperatures. In a first phase, oxygen coming from the surface layers of the ceria–zirconia mixed oxide is consumed and no structural variation of the support is observed. After this induction time, bulk reduction of Pt/ceria–zirconia takes place as a step-like process, while the CO2 production continues at a nearly constant rate. This behavior is totally different from that of the metal-free support in similar reaction conditions, that show a gradual bulk reduction. In repeated oxidation…
A novel mixed valent Cu(II)-Cu(I) 2D framework made of a hydrazone and μ-SCN bridged metallacyclic loops cross-linked by μ3-SCN chains.
2012
A mixed valent copper complex [Cu(II)Cu(I)(L)(μ-SCN)(μ(3)-SCN)](n) (LH = N'-((pyridin-2-yl)methylene)acetohydrazide) has been synthesized and characterized. It is a unique example of a 2D mixed valent Cu(II)-Cu(I) interlinked molecular assembly with a very unusual bridging property of the hydrazone ligand. An extraordinary in situ partial Cu(II)→ Cu(I) reduction is observed in this system at room temperature.
Selective oxidation of propane and ethane on diluted Mo–V–Nb–Te mixed-oxide catalysts
2007
Abstract Te-free and Te-containing Mo–V–Nb mixed oxide catalysts were diluted with several metal oxides (SiO 2 , γ -Al 2 O 3 , α -Al 2 O 3 , Nb 2 O 5 , or ZrO 2 ), characterized, and tested in the oxidation of ethane and propane. Bulk and diluted Mo–V–Nb–Te catalysts exhibited high selectivity to ethylene (up to 96%) at ethane conversions 10 % , whereas the corresponding Te-free catalysts exhibited lower selectivity to ethylene. The selectivity to ethylene decreased with the ethane conversion, with this effect depending strongly on the diluter and the catalyst composition. For propane oxidation, the presence of diluter exerted a negative effect on catalytic performance (decreasing the forma…
A PARTITION TYPE METHOD FOR CLUSTERING MIXED DATA
1990
In this paper, we propose a method for clustering mixed data. The method is a nonhierarchical one, and deals simultaneously with variables of three main kinds: numerical, ordinal, and nominal. It is based on the minimization of a particular criterion f(G。) over all the partitions G。of n entities in m distinct clusters. The criterion is founded on a peculiar kind of internal standardized mean diversity of the entities, according to the three types of variables. The algorithm to get the best partition is also presented: it starts from a non-random choice of the first partition; the results are compared with those obtained by a random assignment to a first partition. In order to show the usefu…
Uso della moneta presso gli Indigeni della Sicilia centro-meridionale
2011
The study of the coins found in the indigenous settlements of Caltanissetta province and the analysis of the related contexts of provenance, have highlighted that in these centers, still in the 4th century BC, the coin was considered a worthless piece of metal and that other bronze objects were used as medium of exchange. It is remarkable the discovery in this territory of three “mixed” hoards, including not only coins, but also of bronze scraps and small fragmentary objects. In this regard, the presence in this area of the so-called "monetary barbarizations" is interesting. They are rare specimens whose stylistic aspect, typological association, technical and, sometimes, even weight elemen…
Strictly convergent algorithm for an elliptic equation with nonlocal and nonlinear boundary conditions
2012
The paper describes a formally strictly convergent algorithm for solving a class of elliptic problems with nonlinear and nonlocal boundary conditions, which arise in modeling of the steady-state conductive-radiative heat transfer processes. The proposed algorithm has two levels of iterations, where inner iterations by means of the damped Newton method solve an appropriate elliptic problem with nonlinear, but local boundary conditions, and outer iterations deal with nonlocal terms in boundary conditions.
LES ÉQUIVOQUES DU « CONSTITUTIONNALISME OCTROYÉ » : UN DÉBAT TRANSATLANTIQUE (I)
2015
In Portugal and in its former colonies, the expression "constitucionalismo outorgado » is part of the constitutional vocabulary since the granting of the Charter of 1826. The French inspiration is obvious ; however, no equivalent expression exists in France. This curiosity leads to measure all the ambiguity of the concept of "granted constitutionalism", an improbable oxymoron according to the president of the Portuguese Republic, Teófilo Braga. Is it about a simple political and linguistic claim, a temporary compromise at the end of a frustrated Revolution? Or does it translate a deeper program, to reconcile both sides of the constitutionalism, ancient and modern ?
Effect of Mycoplasma agalactiae mastitis on milk production and composition in Valle dell Belice dairy sheep
2019
Contagious agalactia (CA), a disease caused by Mycoplasma agalactiae and other pathogenic mycoplasmas, is a well-known multietiological syndrome affecting dairy breeds of sheep and goats in the Mediterranean basin. The aim of this work was to study the effect on milk production and composition of mastitis caused by M. agalactiae in Valle del Belice dairy sheep. All ewes were manually milked twice daily and the milk from both daily milking was analysed for milk composition and somatic cell counts. Moreover the morning milk samples were collected aseptically from each animal for bacteriological analyses. A mixed linear model was utilised to consider milk production and composition between ani…