Search results for "Ceramic"
showing 10 items of 2129 documents
Ceramic technical traditions in the second part of the IVth millennium. The settlement of Twann " Bahnhof " (Bern Canton, Switzerland).
2018
International audience; The neolithic settlement of Twann " Bahnhof " has been excavated during the 1970's. It presents successive sets covering nearly all the second part of the IVth millennium. The ceramic set has been published (Die neolitischen Ufersiedlungen von Twann, 20 volumes, between 1977 and 1981). This dwelling is a reference for the lacustrine research. However, far too little attention has been paid to the technological aspects of ceramics. This communication suggests to reexamine many potteries of the site from late Cortaillod to recent western Horgen, in order to study pottery manufacturing and to reconstitute the " chaînes opératoires ". This case study will allow us to abo…
L'HABITAT DU BRONZE ANCIEN DANS L'EST DIJONNAIS (CÔTE D'OR, BOURGOGNE) : ARCHITECTURE, TERROIR ET TERRITOIRE
2015
The first discoveries concerning the Early Bronze Age in the region of Genlis (Burgundy, Côte d’Or) were madeduring the construction of the A39 motorway, the first major development project to be associated with archaeological monitoring. Excavations made by H. Dartevelle in the early 1990’s revealed two large areas of settlements with two ellipsoidal houses, smaller buildings and satellite structures (Dartevelle 1992). The site of Genlis-Izier, “Le Joannot” remained the only local reference for early Bronze Age habitats until the early 2010’s, when the construction of the L.G.V. Rhin-Rhône considerably updated this data. This article provides a summary of new and existing discoveries, and …
Entanglements, transmission processes and social identities : the technical traditions of ceramics in the Trois-Lacs region and its margins (3600-300…
2019
In Western Europe, the second half of the 4th millennium is a turning point. On the Swiss Plateau, this phase is characterized by the end of Middle Neolithic cultures (Cortaillod and Pfyn) around 3550 BCE, and the emergence of Horgen after 3250 BCE. The transition between these two phases is now better documented thanks to Port-Conty type and Pfyn/Horgen settlements dated around 3400 BCE. This work aims to identify the cultural substract at the origin of the Horgen by characterizing the technical identities and entanglements at the end of the 4th millennium, then by identifying over time the transmission or abandonment of certain ways of making pots in order to determine the share of local …
Ceramique/metal component elaborated by flash sintering for ballistic protection
2012
This dissertation describes the synthesis of new components for ballistic protection with the assistance of flash sintering. Indeed, the objective is to associate two compounds showing very different sintering temperatures – such as alumina and aluminum, two reference materials for ballistic protection applications.The first synthesis method tested was the elaboration of a bi-material via the sintering of aluminump owder on alumina bulks. This study permitted to observe the formation of the alumina/aluminum bonding by scanning and transmission electron microscopy and to optimize the assembly parameters in order to obtain a bimaterials howing a strong interfacial cohesion. Adapted characteri…
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 …
Ceramica indigena dall'abitato di Himera
2010
The research faces, through the evidence analysis in a zone of the upper town settlement, the problem of indigenous pottery meaning in Himera. It as been assured that both the impressed/incised and painted wares are (present) in inconsiderable amount; that shapes are mostly referred to tableware and storage ware; that syntax and decorative patterns fall within indigenous production’s repertory of Western Sicily; that, on the base of discovery ‘s context, most of evidence are placed between the second half of 7th and the first decades of 6th century B.C., in the framework of the first colonial settlement. The pottery evidence in buit-up area of the greek colony in linked to wedding between G…
Parametri tecnologici allo stato plastico e dopo cottura
2011
Asymmetric synthesis of functionalized tetrahydrofluorenones via an NHC-catalyzed homoenolate Michael addition
2018
The first example of an N-heterocyclic carbene-catalyzed asymmetric desymmetrization of enal-tethered cyclohexadienones via an intramolecular homoenolate Michael addition/esterification reaction is described. This new protocol offers a direct entry to various functionalized tetrahydrofluorenones with three contiguous stereocenters in high yields, good diastereoselectivities and excellent enantioselectivities.
Changes in surface stress, morphology and chemical composition of silica and silicon nitride surfaces during the etching by gaseous HF acid
2007
International audience; HF acid attack of SiO2 and Si3N4 substrates is analyzed to improve the sensitivity of a sensor based on inicrocantilever. Ex situ analysis of the etching using XPS, SIMS and AFM show significant changes in the anisotropy and the rate of the etching of the oxides on SiO2 and Si3N4 surface. Those differences influence the kinetic evolution of the plastic bending deflection of the cantilever coated with SiO2 and Si3N4 layer, respectively. The linear dependence between the HF concentration and the Si3N4 cantilever bending corresponds to a deep attack of the layer whereas the nonlinear behavior observed for SiO2 layer can be explained by a combination of deep and lateral …
Ca-P-O thin film preparation, modification and characterisation
2011
Bioceramics are biocompatible ceramic materials, that interact with biological systems of the body to treat, strengthen or replace body functions. Most conventional bioceramics are oxide ceramics, glass ceramics and calcium phosphate ceramics. Among these calcium phosphates, synthetic hydroxyapatite has been extensively studied due to its biomimetic properties similar to that of natural bone. One approach to prepare synthetic hydroxyapatite is to first deposit amorphous Ca-P-O thin film and then by means of post deposition annealing initiate the formation of hydroxyapatite crystals to the film. In addition to the correct film composition and crystalline structure, other surface properties s…