Search results for " ceramic"
showing 10 items of 228 documents
LE SITE CAMPANIFORME DE LUX LA PERROUZE (SAÔNE-ET-LOIRE)
2014
Le site de Lux La Perrouze (Saône-et-Loire) apporte de nouvelles données sur le Campaniforme bourguignon par la découverte d’une petit ensemble céramique remarquablement homogène, contenu dans le remplissage de quatre structures en creux. Cet ensemble se compose essentiellement de céramique commune, mais quelques gobelets décorés sont également à signaler. L’étude de ce mobilier permet de souligner la remarquable homogénéité des productions du groupe campaniforme bourguignon-jurassien tant pour leur chronologie que pour leurs affinités culturelles. The site of Lux La Perrouze (Saône-et-Loire) has provided new data on the Bell Beaker culture of Burgundy by the discovery of a small and remark…
Elaboration de céramiques transparentes Er YAG : synthèse de poudre par co-précipitation et frittage SPS
2013
Yttrium aluminium garnet (YAG, Y3Al5O12) transparent ceramics have attracted much attention since it can replace single crystals as host materials in solid state heat capacity lasers. These polycrystalline ceramics present improved mechanical and spectroscopic properties, as well as a better heat conductivity, lower fabrication costs for larger size materials. Furthermore, it is possible to reach higher doping concentrations as well a uniform distribution. Doping YAG with Erbium (Er:YAG) allows eye-safe emission at 1645nm. Moreover, a low doping rate (0.5%at.) enables upconversion process during laser operation. Conditions for transparency are amongst others, the absence of defects, a high …
Parametri tecnologici allo stato plastico e dopo cottura
2011
Céramiques diélectriques commandables pour applications micro-ondes : composites à base de titanate de baryum-strontium et d'un oxyde non ferroélectr…
2001
Since the last decades, dielectric ceramics have been considered as attractive for microwave applications as tunable dielectric resonators or phase shifters. For that, ceramic devices should be tunable – change in dielectric constant with applied voltage- with moderate to low dielectric constant (30 to 1000) and loss tangent as low as possible. To reconcile these properties, composite ceramics based on Ba0.6Sr0.4TiO3 (BSTO) and a non-ferroelectric oxide with a low dielectric constant (MgTiO3 or MgO) were synthesised. The aim of this study was to correlate the microstructure with the dielectric properties, especially the Curie temperature and the dielectric relaxation phenomena.Ceramics with…
Corpus Vasorum Antiquorum, Agrigento, Museo Archeologico Regionale 2
2005
Il volume raccoglie i vasi italioti e sicelioti a figure rosse già appartenuti al Museo Civico di Agrigento e alla Collezione Giudice, ed esemplari provenienti da scavi compiuti dalla Soprintendenza Archeologica tra gli anni ‘50 e gli anni ‘70 del Novecento sia ad Agrigento che nel territorio, in buona parte inediti o solo appena citati in bibliografia. I vasi sicelioti dei due nuclei collezionistici dovevano provenire dalle necropoli greche di Agrigento e Gela; i vasi italioti dovettero invece essere acquistati sul mercato antiquario dell'Italia Meridionale, benchè non sia da escludere anche in taluni di questi casi una provenienza locale-regionale. Di particolare interesse risultano i vas…
Monitoraggio dell'attività biologica marina su provini ceramici: nuovi approcci metologici
2015
II deterioramento dei manufatti lapidei e ceramici sommersi è un processo che si sviluppa attraverso eventi fisici, chimici (abrasione, deposizione, ossidazione e riduzione ) e biologici attraverso la colonizzazione biologica da parte di microrganismi prima e di macrorganismi successivamente (Lopez-Arce et al. 2013, Aloise et al. 2013), in quanto i materiali forniscono un substrato di attacco per la loro crescita. In un recente progetto PRIN dal titolo "Approcci innovativi per lo studio sperimentale di manufatti ceramici “sommersi" sono stati valutati gli effetti delle diverse condizioni di giacitura dei reperti ceramici e del conseguente deterioramento, mediante uno studio multidisciplinar…
Heat-resistant unfired phosphate ceramics with carbon nanotubes for electromagnetic application
2014
Composite materials, containing low concentrations of carbon nanotubes (CNTs) of three different diameters and heat-resistant phosphate ceramic as a matrix were prepared by cold-pressing method. Their dielectric properties were studied at room temperature in a wide frequency range (20 Hz–1 MHz). It was found experimentally and proved theoretically via modeling of the composites as a random capacitor–resistor–diode network that electrical percolation concentration depends significantly on the diameter of the nanoinclusions. The main conclusion is that the best candidate providing both the lower percolation threshold and high absolute values of ac conductivity is thinner carbon nanotubes (in …
disegni di materiali ceramici dagli scavi della Montagnola di Marineo, Tavv. CLXIX-CLXXI, CLXXIV
2000
Disegni di materiale ceramico proveniente dallo scavo del sito della Montagnola di Marineo (Palermo) drowings of pottery coming from the excavations of the archaeological site "La Montagnola" of Marineo (Palermo)
An original experimental approach to study the alteration and/or contamination of archaeological ceramics originated by seawater burial
2014
This paper deals with the proposal of an original experimental methodological approach specifically designed for appraising any compositional alteration and/or contamination of archaeological ceramics after the protracted contact with seawater. A series of ceramic test-pieces (briquettes and cylinders) were purposely manufactured by mixing selected calcareous or non-calcareous clays with different varieties of sieved sand temper. The aim was to reasonably simulate the ceramic pastes most frequently found in the shipwrecks recovered in the coastal areas of western Mediterranean. The used raw materials were previously characterized in terms of mineralogical and chemical composition (XRPD, XRF…
Effect of in Doping on the ZnO Powders Morphology and Microstructure Evolution of ZnO:In Ceramics as a Material for Scintillators
2018
Transparent ZnO ceramics are of interest for use as material for high-efficiency fast scintillators. Doping ZnO ceramics in order to improve complex of their properties is a promising direction. In the present research, the role of indium in the ZnO nanopowders surface interactions and in the change of microstructures and photoluminescence (PL) characteristics of sintered cera-mics is considered. Undoped and 0.13 wt% In doped ZnO ceramics are obtained by hot pressing sintering. It has been found that indium leads to the transition of initially faceted ZnO particles to rounded, contributing to good sintering with formation of diffusion active grain boundaries (GBs). Unlike ZnO ceramics, ZnO:…