Search results for "surface"

The impact of the age of vines on soil hydraulic conductivity in vineyards in eastern Spain

2017

Soil infiltration processes manage runoff generation, which in turn affects soil erosion. There is limited information on infiltration rates. In this study, the impact of vine age on soil bulk density (BD) and hydraulic conductivity (Ks) was assessed on a loam soil tilled by chisel plough. Soil sampling was conducted in the inter row area of six vineyards, which differed by the age from planting: 0 (Age 0; just planted), 1, 3, 6, 13, and 25 years (Age 1, Age 3, Age 6, Age 13, and Age 25, respectively). The One Ponding Depth (OPD) approach was applied to ring infiltration data to estimate soil Ks with an α* parameter equal to 0.012 mm-1. Soil bulk density for Age 0 was about 1.5 times greate…

Carbons from second generation biomass as sustainable supports for catalytic systems

2018

Abstract In this study activated carbons were produced from the wood of three different wood species (pine, birch, spruce). The resulting activated carbons were characterized in bulk for ash content, carbon content (elemental analyses), specific surface area, and pore size distribution, and at the surface by measuring the autogenerated pH and studying their structure by XPS. All the samples presented high surface areas and appeared to be mesoporous materials (mesopores >80%). The carbons were then used as support for AuPt nanoparticles and tested in the liquid phase oxidation of glycerol (GLY) and in the hydrogenation of levulinic acid (LA), two important chemicals from cellulose-based biom…

Cartographic Language in Thematic Maps

2015

This paper analyzes the effectiveness of maps as transmitters of information. To this end, some basic concepts concerning the properties of cartographic language are examined, with the aim of helping the reader design maps conveying geographic information as clearly as possible. It also describes the innate taste of geographers for maps –how these attract and stimulate them. Then it deals with the emergence of the Internet and the new technologies allowing massive map visualization, downloading and production. The paper is illustrated with ten thematic maps, in which visual variables (i.e. size, shape, value, color, orientation and texture) are combined with the different marks (points, lin…

Density Functional Theory Investigation on the Nucleation and Growth of Small Palladium Clusters on a Hyper-Cross-Linked Polystyrene Matrix

2014

Density functional theory calculations were employed to investigate the nucleation and growth of small palladium clusters, up to Pd9, into a microcavity of the porous hyper-cross-linked polystyrene (HPS). The geometries and the electronic structures of the palladium clusters inside the HPS cavity, following the one-by-one atom addition, are affected by a counterbalance between the Pd–phenyl (Pd−Φ) and Pd–Pd interactions. The analysis performed on energetics, cavity distortions, and cluster geometries indeed suggest that the cluster growth is dominated by the Pd−Φ interactions up to the formation of Pd4 aggregates, whereas the metal–metal interactions actually rule the growth of the larger c…

A general diastereoselective synthesis of highly functionalized ferrocenyl ambiphiles enabled on a large scale by electrochemical purification

2017

International audience; A general synthesis of highly functionalized ferrocenes, which include (P,B)- and (N,B)-ambiphiles, has been developed at a multigram scale. Diastereoselective stepwise modification of di-tert-butylated ferrocenes included the unprecedented separation of electroactive species. Bulky alkyl groups on ferrocenes ensure planar chirality of ambiphiles and enforce closer proximity of antagonist Lewis functions.

Reversible self-assembly of metal chalcogenide/metal oxide nanostructures based on Pearson hardness.

2010

Nanotechnology has reached a stage of development where not individual nanoparticles but rather systems of greater complexity are the focus of concern. These complex structures incorporate two or more types of materials, an example of which is the formation of metal–semiconductor hybrids, which effectively combine the properties of both materials. The assembly of multicomponent nanoparticles from constituents with different optical, electrical, magnetic, and chemical properties can lead to novel functionalities that are independent of the individual components and may be tailored to fit a specific application. These applications include such far-reaching challenges as solar energy conversio…

MODIFICA SUPERFICIALE DI FILM DI POLY(ETILENE-co-ACIDO ACRILICO) CON NANOPARTICELLE DI SILICE ATTIVATA

2009

Coordination chemistry on surfaces through vapor phase processing: smart molecular/graphene heterostructures based on spin-crossover complexes and 2D…

2023

Los compuestos de coordinación están últimamente focalizando la atención de los investigadores en el campo de la nanociencia. Particular interés están generando aquellos compuestos con propiedades magnéticas de cara a su integración a la nanoescala en ramas como la electrónica y/o la espintrónica moleculares. Sin embargo, para su uso real en dispositivos destinados a estas aplicaciones, su procesabilidad es un requisito indispensable. En el marco de esta necesidad, la presente tesis doctoral se ha destinado al estudio del procesado sobre superficies mediante técnicas de fase gas de dos tipos distintos de compuestos de coordinación. Por tanto, el trabajo se ha dividido en dos partes. La prim…

Theoretical evaluation of structures and energetics involved in the hydrogenation of hydrocarbons on palladium surfaces

2001

Abstract Quantum mechanical calculations were employed to deepen information about the basic properties of the mechanism occurring in the palladium catalytic hydrogenation involving surface hydrogen species of unsaturated hydrocarbons. Activation energy values of elementary events implicated in the whole reaction were computed by potential energy surface analyses, to determine the corresponding occurrence probabilities of the same events. Different surface hydrogen species were pointed out and their relevance in the overall surface process was discussed together with their geometrical and chemical characteristics.

Inhibitoren der Korrosion 27 (1). Inhibitoren der Korrosion von Kupfer - Gibt es eine Struktur-Wirkungsbeziehung?

1982

Mehr als 570 Verbindungen der unterschiedlichsten Struktur wurden unter Standardbedingungen im “Schuttelversuch” und pH-statisch auf ihre Korrosionsschutzwirkung gegenuber Kupfer getestet und mit Hilfe eines Computers ausgewertet. Die erhaltenen Ergebnisse stehen relativ haufig in Ubereinstimmung mit Dem “Hart-Weich-Konzept” von Pearson. Eine gezielte Synthese von Inhibitoren, die sich in diesem Konzept orientiert, ist jedoch nicht moglich. Inhibitors of corrosion 27 (1). Inhibitors of the corrosion of copper Does there exist a structure-effect-relation? Over 570 compounds of greatly varying structure have been tested under controlled conditions in agitation and pH-stat experiments designed…