Search results for "composition"
showing 10 items of 2675 documents
Stability and nature of the volume collapse of ε-Fe2O3 under extreme conditions
2018
Iron oxides are among the major constituents of the deep Earth’s interior. Among them, the epsilon phase of Fe2O3 is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local env…
PAUL CÉZANNE EN L’INICI LITERARI DE JOAN VINYOLI / PAUL CÉZANNE IN THE EARLY WORKS OF JOAN VINYOLI
2018
Joan Vinyoli, aquest treball aprofundeix en l’interes que el poeta txec li va traslladar per la pintura de Cezanne i per la seua doctrina de la composicio artistica. L’aprofundiment d’aquesta relacio interdiscursiva entre pintura i poesia s’exemplifica en la hipertextualitat que hi ha en dos poemes primerencs de Vinyoli, provinents dels seus dos primers poemaris, basats cadascun en dos quadres del pintor frances i elaborats des de la transformacio seriosa o transposicio en paraules. Paraules clau: Cezanne, Vinyoli, quadres, poemes. Abstract: Starting with a review of Rilke’s literary influence on the early poetic writings of JoanVinyoli, this paper goes on to delve more deeply into how the …
Actuality of Art Education at the Beginning of XX Century in East Europe. Graphic Constructions Through Gestaltung and Formenlehre in Figurative Crea…
2018
The great innovations in the field of the elaboration of forms and figures in the last century have often sometimes accompanied the amazement and optimism of the discovery, a methodological uncertainty shared with other fields of Knowledge. It is undeniable that the advent of information technology and representation—together with the socio-economic changes that have taken place—has laid the foundations for an irreversible ontological leap in the process of form processing, and yet very often there are references historians that can somehow inspire current theories and practices. In this sense, some interpretations considered to be classical, from Valery to Benjamin, from Arnheim to Waburg,…
Volatile constituents of Stachys palaestina L. (Palestine woundwort) growing in Lebanon
2014
The hydrodistillation of the aerial parts of Stachys palaestina L. collected in Lebanon in the Kadisha Valley, yielded 0.1% (w/w) of essential oil. GC and GC-MS analyses enabled the identification of 87 compounds representing 90.8% of the total oil. Hexadecanoic acid (10%), hexahydrofarnesyl acetone (6.9%), eugenol (4.3%) and (E)-caryophyllene (4.3%) were the main components. On the whole, the oil was constituted mainly of sesquiterpenes (37.7%), among which sesquiterpene hydrocarbons (20.7%) slightly prevailed over oxygenated sesquiterpenes (17.0%). This is the first report on the chemical composition of S. palaestina essential oil.
Characterization of foxing stains in early twentieth century photographic and paper materials
2016
The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the …
Microbial community structure in soils with decomposing residues from plants with genetic modifications to lignin biosynthesis
2006
Lignin is a major determinant of the decomposition of plant materials in soils. Advances in transgenic technology have led to the possibility of modifying lignin to improve the pulping properties of plant materials for papermaking. Previous studies have shown that lignin modifications also affect the rate of plant material decay in soil. The aim of this work was to investigate short-term changes in soil microbial community structures when tobacco residues with reduced activity of enzymes in the monolignol pathway decompose. The residues from lignin-modified plants all decomposed faster than unmodified plant materials. The relative proportions of some of the structural groups of microbial ph…
Parallel Schwarz methods for convection-dominated semilinear diffusion problems
2002
AbstractParallel two-level Schwarz methods are proposed for the numerical solution of convection-diffusion problems, with the emphasis on convection-dominated problems. Two variants of the methodology are investigated. They differ from each other by the type of boundary conditions (Dirichlet- or Neumann-type) posed on a part of the second-level subdomain interfaces. Convergence properties of the two-level Schwarz methods are experimentally compared with those of a variant of the standard multi-domain Schwarz alternating method. Numerical experiments performed on a distributed memory multiprocessor computer illustrate parallel efficiency of the methods.
Paramagnetic Mono- and Polyhydrides of the Transition Metals
2001
Publisher Summary This chapter reviews the methods used for the synthesis or generation of paramagnetic hydride complexes. It subsequently surveys the known classes of stable open-shell hydride complexes. The chapter also reveals the fundamental properties of the M–H bond in open-shell compounds and finally examines the various established decomposition modes. The classical picture of the terminal M–H bond is that where the hydrogen atom is orbital and combines with an appropriate metal-fragment hybrid orbital to generate the bonding and antibonding combinations. The chapter also elaborates the paramagnetic hydride complexes, which are thermally sensitive compounds and are unstable toward a…
ANOVA-MOP: ANOVA Decomposition for Multiobjective Optimization
2018
Real-world optimization problems may involve a number of computationally expensive functions with a large number of input variables. Metamodel-based optimization methods can reduce the computational costs of evaluating expensive functions, but this does not reduce the dimension of the search domain nor mitigate the curse of dimensionality effects. The dimension of the search domain can be reduced by functional anova decomposition involving Sobol' sensitivity indices. This approach allows one to rank decision variables according to their impact on the objective function values. On the basis of the sparsity of effects principle, typically only a small number of decision variables significantl…