Search results for "Metallurgy"
showing 10 items of 1419 documents
Modeling lead input and output in soils using lead isotopic geochemistry
2004
The aim of this study is to model downward migration of lead from the plow layer of an experimental site located in Versailles (about 15 km southwest of Paris, France). Since 1928, samples have been collected annually from the topsoil of three control plots maintained in bare fallow. Thirty samples from 10 different years were analyzed for their lead and scandium contents and lead isotopic compositions. The fluxes are simple because of the well-controlled experimental conditions in Versailles: only one output flux, described as a first-order differential function of the anthropogenic lead pool, was taken into account; the inputs were exclusively ascribed to atmospheric deposition. The combi…
Raw material procurement and selection in Southeast Iberia’s early metallurgy
2020
The role of metallurgy in the Copper Age communities of the Iberian Southeast is a recurrent question of archaeological research in western Europe. Based on lead isotope and trace element analyses of archaeometallurgical remains, this paper addresses the territorial organisation of metallurgical production during the Copper Age (3100-2200 cal BC) in the Vera Basin (Almería, Spain), the region with the earliest metallurgical evidence in western Europe. This paper comprises the study of materials from the three main settlements with metallurgical activity in the area (Las Pilas, Santa Bárbara and Almizaraque), as well as some metal objects from these and other sites (La Encantada I, Loma…
Cinq millénaires de métallurgie en montagne basque. Les apports d'une démarche intégrée alliant palynologie et géochimie isotopique du plomb
2001
Five thousand years of metallurgy in the basque mountains : the contributions of an integrated process mixing palynology and the isotopic chemistry of lead. An interdisciplinary research combining palyno- logy and lead isotopic geochemistry was performed in a peat bog of the Basque Country, in an area recognized as being an old metallurgical centre. These various analyses make it possible to reconstitute mining and metallurgical activities and to appreciate the impact on forest during last five millennia. Several phases are attested between late Neolithic and modern times (Middle Bronze age, Late Bronze age, Antiquity and finally modern time). Most of these phases are clearly related to for…
Structural and hydrogenation study on the ball milled TiH2–Mg–Ni
2015
International audience; With the aim of further understanding for TieNieMg alloys and their hydrogenation behavior, powders of TiH2, Mg and Ni with the molar ratio of 3:1:2 have been mechanically milled for 10 h, 20 h, 30 h, 40 h according to the stoichiometry (TiH2)1.5Mg0.5Ni. Microstructures of the milled sample were analyzed and their hydrogenation properties as negative electrodes for Ni-MH batteries were studied. Phase change with milling time revealed the fast formation of the Ti-Mg-H FCC phase. The alloying priority among Ti, Mg and Ni was demonstrated by comparing phase compositions in different milling time. Hydrogen capacities evaluated by both solidegas reaction and electrochemic…
A simple method for estimating downward longwave radiation from surface and satellite data by clear sky
1990
Abstract An attempt to derive downward longwave radiation at the surface in clear sky conditions is presented. A method that integrates satellite-measured infrared radiation temperatures with ground measurements of water vapour pressure is applied to Meteosat data. Satellite-derived fluxes are compared with corresponding ground-measured fluxes at three different sites in France and during various seasons. Comparison of the daily averaged fluxes shows a correlation coefficient of 0–88 and an r.m.s. difference between satellite estimates and ground measurements of 12 Wm-2.
Development of Removable Visual Impact Indicator or Polymer Composite Materials
2021
The prototype of removable visual impact indicator for thermoset polymer composite materials is developed, and its characteristics are experimentally determined. The indicator is a fabric tape glued by epoxy to the surface of the polymer composite. The tape is impregnated with a composition that provides a visual response at the place of an impact on the composite surface. Ball-drop tests demonstrated the increase of the magnitude of the visual response with the impact energy at different substrate hardnesses. The shelf-life and mode of the tape storage until commissioning are determined. Peel tests showed the ability to remove a used indicator without damaging the surface of the composite.
Effects of defects on the tensile strength of short-fibre composite materials
2014
Abstract. Heterogeneous materials tend to fail at the weakest cross-section, where the presence of microstructural heterogeneities or defects controls the tensile strength. Short-fibre composites are an example of heterogeneous materials, where unwanted fibre agglomerates are likely to initiate tensile failure. In this study, the dimensions and orientation of fibre agglomerates have been analysed from three-dimensional images obtained by X-ray microtomography. The geometry of the specific agglomerate responsible for failure initiation has been identified and correlated with the strength. At the plane of fracture, a defect in the form of a large fibre agglomerate was almost inevitably found.…
Tērvetes pilskalna akmens lejamveidnes
2017
No analizētajām Tērvetes pilskalna 25 lejamveidnēm 2 ir pusfabrikāti. 10 veidnēs liets metāls, 11 bijusas nelietotas, 2 veidnēm lietosana nav nosakāma. 10 veidnes bija t.s. vāciņi - veidnes apģērba apsuvju un piekariņu aizmugures iegūsanai. Septiņas veidnes bijusas apvērsamās - ar ielietnēm akmens plāksnīsu augsā un apaksā. Akmens plāksnītes - lejamveidnes izgatavosanas procesā ir slīpētas un atsevisķos gadījumos pulētas. Veiddobumi pārsvarā izgriezti ar nazi.---The article analyses 25 finished and semi-manufactured stone casting moulds found at the hill-fort of Tērvete, dated to the 11th–13th century. In terms of construction they all are two-part moulds. Ten moulds have been used for cast…
Material flow analysis in dissimilar friction stir welding of AA2024 and Ti6Al4V butt joints
2016
The complex material flow occurring during the weld of dissimilar AA2024 to Ti6Al4V butt and lap joints was highlighted through a dedicated numerical model able to take into account the effects of the different materials as well as the phase transformation of the used titanium alloy.
Cernay-lès-Reims (Marne). Cernay-lès-Reims « le Bas de la Noue Saint Rémy » zone 9 [notice archéologique]
2019
Localisée en limite SE de l’agglomération rémoise, sur la commune de Cernay-les-Reims, l’emprise de l’opération porte sur une surface de 11 300 m2. Cette neuvième concentration de vestiges, fouillée sur un parc d’activité, correspond à un établissement rural de l’Antiquité tardive, prolongé à l’époque médiévale par une zone d’activité artisanale. Ces deux occupations se développent le long d’un axe de circulation qui perdure vraisemblablement de l’Antiquité à la première guerre mondiale.