Search results for "métal"

Photo-thermal control of surface plasmon mode propagation at telecom wavelengths

2016

Surface plasmon polaritons (SPPs) is the promising versatile platform proposed for guiding electromagnetic waves at nanoscale dimensions. In this context dynamic control of SPPs prop- agation is of paramount importance. Thermo-optical (TO) effect is considered as an efficient technique for performing active control of plasmonic devices. Among the thermo-optical based plasmonic devices demonstrated so far TO coefficient is dominantly provided by a dielectric material on top of the metal sustaining the SPP mode, however, the role of TO properties of the metal has been rarely investigated for plasmonic applications especially at the telecom frequency ranges. Therefore, the aim of this thesis i…

Dissimilar joining of copper to stainless steel and TA6V to stainless steel by high power beams : understanding and modeling of physicochemical pheno…

2010

The present study is dedicated to the comprehension of the mechanism of materials mixing during dissimilar welding by high power beam sources. We have been interested in joining of two couples of metallic materials which present different metallurgical problems: •copper- stainless steel (miscibility gap, important difference in physical properties);•TA6V- stainless steel (oxidation on air, formation of intermetallic phases which made the joint brittle).For the first couple of materials, continuous laser Nd:YAG welding and electron beam welding have been applied. The experimental study of morphology evolution, composition, microstructure and mechanical properties has allowed establishing the…

Niveaux de formation et qualifications

1972

Producing and working with iron

2019

Combining archaeological studies and archaeometric analyses, this synthesis presents the importance of the iron economy in the eastern part of the Paris Basin from the First Iron Age to the early Middle Ages. The first contributions of this research project concern technological changes in the production system of iron objects. The attention paid to the share of recycling in production somewhat modifies the previous discourse in attempts to quantify the types of forged objects (tools, weapons, ornaments, etc). Additionally, the link between the status of the excavated sites (agricultural holding, rural hamlet, fortified site, large settlements) and the type of forging activity that was carr…

Experimental investigation and multi-scale modelling of the behavior of mechanically activated metallic powders : from binary systems to High Entropy…

2021

Generally, metal alloys consist of a main element associated with other elements present in smaller quantities such as iron, nickel, aluminum or copper alloys. The precise composition of an alloy is adjusted according to the required performance: high temperature behavior, corrosion resistance, mechanical properties, durability ... In 2004, a Taiwanese scientist, JW Yeh, had the idea of making an alloy base of several elements, at least 5, whose composition in the alloy varies between 5% and 30% at. Yeh invented the high entropy alloy (HEA). Mixed on a microscopic scale, the metals form a remarkably stable solid solution. The explanation is thermodynamic. An alloy is all the more stable as …

Du monnayage au crypto-monnayage

2020

Minting Techniques in Currencies and Cryptocurrencies. Over the past ten years, the creation of bitcoin and other cryptocurrencies has renewed the debate on the nature of money. This paper discusses the comparison between cryptocurrencies and coins : after describing their ideological and technical foundations, we explain the reasons why the reference to metals is often invoked. We then detail the techniques of minting, the processes of marking, and the question of seigniorage.

La grotte de l'Eremita au Monte Fenera (Vercelli, Italie) : nouvelles découvertes du Bronze moyen

2014

Située au coeur du massif calcaire du Monte Fenera dans le Piémont italien, la grotte de l'Eremita, appelée également Tana dell'Armittu, fait l'objet d'une intervention archéologique menée par l'Université de Genève (direction M. Besse). Suite à des sondages effectués en 2012 lors desquels furent mises au jour, entre autres, des perles spiralées et une épingle en bronze, une fouille programmée a été organisée dès 2013. Notre contribution présente les données de terrains de l'année 2013. La fouille archéologique s'est déroulée avec les étudiants en archéologie, l'aspect didactique - auquel nous sommes fermement attachés - étant un des objectifs de cette fouille.

Designing biochar properties through the blending of biomass feedstock with metals: Impact on oxyanions adsorption behavior

2018

Metal-blending of biomass prior to pyrolysis is investigated in this work as a tool to modify biochar physico-chemical properties and its behavior as adsorbent. Six different compounds were used for metal-blending: AlCl3, Cu(OH)2, FeSO4, KCl, MgCl2 and Mg(OH)2. Pyrolysis experiments were performed at 400 and 700 °C and the characterization of biochar properties included: elemental composition, thermal stability, surface area and pore size distribution, Zeta potential, redox potential, chemical structure (with nuclear magnetic resonance) and adsorption behavior of arsenate, phosphate and nitrate. Metalblending strongly affected biochars' surface charge and redox potential. Moreover, it incre…

The Pratz le Curtillet settlement

2016

Among the earliest habitats of the early Middle Ages studied in Franche-Comté, the Pratz le Curtillet a settlement sets itself apart by its location in the Jura highlands, renowned for its remoteness and inhospitable landscapes. On the Lizon plateau, the scope of the archaeological work explored on the 16 hectares and the quality of the remains still constitute an exceptional complex today. An imposing 16m by 13m stone building flanked by an annex forms the residential part of the estate, while sheltering fodder and livestock, while the second building houses a forge. Domestic and artisanal equipment provide ample documentation on the living conditions of this small community of high status…

Sanctuaries and rural settlements along the Roman road Lyon-Trier on the civitates of the Lingoni

2015

From a memory of a master on the study of the material from the sanctuary of Beire-le-Châtel "The Pâtis the Letto" as well as new studies such as material from the fanum Lux "Le Bois Giraud", the objective of this thesis is to understand the people who live along the Roman road Lyon - Trier on the civitates of the Lingoni et go on these places of worship. The material found in these sanctuaries was confronted with one of the rural settlements to distinguish local attendance and passing travelers. Finally, the study allows to emphasize the role of settlements - administrative center of the city and secondary towns - and communication routes in the genesis of Lingones’ places of worship but a…