Search results for " materia"
showing 10 items of 18071 documents
Influence of the Resin Layer Thickness at the Interface of Hybrid Metal-composite Co-cured Joints
2011
As discussed in literature, the accurate analysis of the modern co-cured joints between composite materials or between a metal and a composite material (hybrid joints) is complicated by the influence of the interface resin layer on the interface singular stress field. In such joints, in fact, there is not a proper adhesive layer and the thickness of the resin layer, that plays the role of the adhesive, is not constant due to the presence of the reinforcing fibers in the composite adherent. For this reason several authors assume that a generic co-cured joint can not be studied as a simple bi-material joint, without considering the particular characteristics of the actual resin layer. This pr…
Experimental Investigation on Stiffness and Strength of Single-Lap Z-Pinned Joints in a Laminated CFRP Stress-Ribbon Strip
2016
Carbon fiber-reinforced polymer (carbon-polymer) is an advanced lightweight composite material with high strength and excellent resistance to corrosion and fatigue. Over the past decades, application of fiber-reinforced polymers has been spread from the aerospace to other branches of industry such as automobile and civil engineering. Unidirectional carbon-polymers have a high potential for replacing steel in tensile members. Recently, the first carbonpolymer stress-ribbon bridge has been constructed in Germany. The non-laminated strip-loop carbon-polymer thin strips were used as the load bearing components in this bridge. In comparison with the laminated components, the applied cables are c…
Etäoppimateriaalin rakenteistaminen
1997
Rola efektu podstawnikowego w sprzężeniu π-elektronowym w N-podstawionym karbazolu
2019
Modyfikacja właściwości optoelektronowych materiałów organicznych w wielu przypadkach sprowadza się do wywołania zmian w ich strukturze elektronowej, a w szczególności w π-elektronowej delokalizacji w obrębie całej molekuły. Dużą uwagę zajmują w tych badaniach układy skondensowane zawierające pierścienie aromatyczne, niearomatyczne oraz hetero atomy. Do układów tych można zaliczyć, między innymi, karbazol i jego pochodne, który znajduje zastosowanie w organicznych materiałach optycznych i elektronowych. W niniejszej publikacji zaprezentowano wyniki z przeprowadzonych badań nad wpływem podstawienia pierścienia fulwenowego na atomie azotu oraz podstawników o zróżnicowanym charakterze elektron…
"Chimica Attiva"
2008
Un percorso di chimica che, prendendo spunto dall'osservazione dei fenomeni, si propone di offrire un'interpretazione della struttura della materia e delle sue trasformazioni
Il degrado degli stucchi serpottiano a Palermo in relazione alle condizioni ambientali di conservazione
2009
This work is part of a demanding project, called “Progetto Serpotta”, performed since 2000 in cooperation with Soprintendenza Beni Culturali of Palermo. Aim of the project is the restoration of the unique stucco's artworks moulded by Giacomo Serpotta and his co-workers end of 17th -beginning of 18th century. This paper is focused on the problem of salt efflorescences, that are widely present in all of the churches and oratories restored in the framework of “Progetto Serpotta”. Particular attention is given to the relationship between the constitutive matter of the stuccoes, as analysed by means of both X ray diffractometry and optical microscopy, and the salts composition, as analysed by me…
The skill in materials selection and processing at the Serpotta's studio during the baroque period in Palermo
2010
Aristocratic power exaltation between XVI and XVIII centuries in Palermo Area: psychological and symbolic aspects behind suburban villas' constructio…
2014
From ancient times, due to a very favourable climate, and the presence of many pure water sources, the “Golden Valley” surrounding the city of Palermo saw the settlement of an elaborate system of rural farms, “industrial” buildings. During the XVI century, and especially towards the XVIII century, spending some time in the countryside became a real trend for the urbanized Sicilian aristocracy. Thus, such buildings were slowly renewed into sumptuous suburban palaces to exhibit feudal family richness and power as well as to make living in the countryside more pleasant. In western Sicilian area, the architectural typology of the suburban villa is locally characterized by a mixture of the luxur…
Copper-hydride nanoclusters with enhanced stability by N-heterocyclic carbenes
2021
AbstractCopper-hydrides have been intensively studied for a long time due to their utilization in a variety of technologically important chemical transformations. Nevertheless, poor stability of the species severely hinders its isolation, storage and operation, which is worse for nano-sized ones. We report here an unprecedented strategy to access to ultrastable copper-hydride nanoclusters (NCs), namely, using bidentate N-heterocyclic carbenes as stabilizing ligands in addition to thiolates. In this work, a simple synthetic protocol was developed to synthesize the first large copper-hydride nanoclusters (NCs) stabilized by N-heterocyclic carbenes (NHCs). The NC, with the formula of Cu31(RS)2…
Ray optics behavior of flux avalanche propagation in superconducting films
2015
Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a $0.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ thick metal layer, the refractive index was close to $n=1.4$. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal …