Patrice Lehuédé - Academia.edu (original) (raw)

Papers by Patrice Lehuédé

Journal of archaeological science: Reports/Journal of archaeological science: reports, Apr 1, 2024

The invention relates to a mineral wool which can be dissolved in a physiological medium and whic... more The invention relates to a mineral wool which can be dissolved in a physiological medium and which comprises the following constituents according to the following percentages by weight: SiO2 39-44%, preferably 40-43%, A12O316-27%, preferably 16-26%, CaO 6 -20%, preferably 8-18%, MgO 1-5%, preferably 1-4, 9%, Na2O 0-15%, preferably 2-12%, K2O 0-15%, preferably 2-12%, R2O (Na2O + K2O) 10-14,7%, preferably 10-13.5% P2O50-3%, i.e.0-2% Fe2O3 (total iron) 1,.5-15%, i.e.3,2-8%, B2O30-2%, preferably 0-1%, TiO20-2%, preferably 0.4-1%.

Le plomb dans les matériaux vitreux du patrimoine

Ce chapitre donne des indications générales sur les avantages liés à l’introduction du plomb dans... more Ce chapitre donne des indications générales sur les avantages liés à l’introduction du plomb dans la composition des verres et des glaçures, en particulier vis-à-vis de leurs propriétés physiques (viscosité, dilatation, densité, propriétés optiques, mécaniques…) et chimiques (durabilité, rédox…). Il montre également des difficultés qui peuvent résulter de l’emploi de cet élément.

Microchemical Journal, Mar 1, 2018

Twenty three glass bracelets fragments of different colors and appearances excavated at Păcuiul l... more Twenty three glass bracelets fragments of different colors and appearances excavated at Păcuiul lui Soare, Dobrogea, Romania and dated to the 10 th-11 th century AD were analyzed for their chemical composition using Particle-Induced X-ray Emission (PIXE) and Particle-Induced Gamma-ray Emission (PIGE) techniques at AGLAE accelerator of Centre de Recherche et de Restauration des Musées de France (C2RMF), Paris. Analytical data showed that all bracelets are soda-lime-silica glass of intermediate recipes, with compositional patterns between the natron and plant ash ranges, indicating practices of extensive glass recycling. Păcuiul lui Soare glass bracelets turned out to be similar in composition with the ones found in other nearby coeval sites, but also with bangles discovered in more remote Byzantine sites. The analyses revealed that the same technological choices have been made to produce the bracelets, namely they have been produced in workshops that had access to vitreous artefacts of different compositions, i.e. produced using distinct types of fluxes. Recycling seem to be a characteristics for all glass bangles produced in the Byzantine Empire at the end of the first millennium AD, regardless of their finding place and dating. As concerning the glass color, blue hues in Păcuiul lui Soare were induced by the presence of small amounts of cobalt (hundreds of ppm), while the green and black colors were

Chemischer Informationsdienst, Sep 11, 1973

Presses universitaires de Paris Nanterre eBooks, 2019

Green copper organometallic pigments have been known since Antiquity. Some of them, such as verdi... more Green copper organometallic pigments have been known since Antiquity. Some of them, such as verdigris and copper resinate, were widely used in easel paintings from the 15th to 17th centuries, for their transparency, brilliance and pure green tones. However these pigments often undergo chromatic modifications, like browning or darkening. This phenomenon is not systematic, and altered and non-altered areas can coexist in a same painting. The understanding of the darkening process is crucial for conservation issues, to improve the readability of degraded paintings and decide how to treat them.

Scanning, 2006

Using primary beam energies E0 ranging from 0.2 to 15 keV and an in-lens detector, a series of im... more Using primary beam energies E0 ranging from 0.2 to 15 keV and an in-lens detector, a series of images of the same region of an artificial microstructured diamond sample have been acquired in scanning electron microscopy. Next, the images were analysed by using a scatter diagram technique to underline the topographic contrast change and contrast reversal. The results obtained from 0.5 to 15 keV are discussed with the help of an expression derived from the constant loss model for the secondary electron yield delta of diamond, but including the respective roles of the angle of incidence, i, and of the angle of detection, alpha. More surprising is the quality of images obtained at a beam energy as low as 0.2 keV, and more difficult to explain is the significant contrast change between 0.2 keV and 0.5 keV. For the first time, scatter diagrams are used as a diagnostic tool in scanning electron microscopy, and after some improvements it is hoped that the experimental approach followed here may lead to quantitative estimates of the local tilts of a specimen surface.

Journal of Electron Spectroscopy and Related Phenomena, 1992

Abstract Most of the materials in the human environment are insulators and their investigation us... more Abstract Most of the materials in the human environment are insulators and their investigation using incident particles leads to difficulties because of charging effects. The physical properties of insulators are first briefly summarized, and then a critical analysis of the approach generally used for explaining these effects, based on the total yield of the emitted particles, is undertaken. An alternative is the electrostatic approach that allows us to take into account the influence of the experimental conditions and the nature of the surrounding media. This also allows us to explain some practical solutions for reducing charging effects or taking advantage of them, but the main problem is to find the microscopic causes of the trapping of charged particles. These charging effects are illustrated by various experimental results and concern analytical techniques such as Auger electron spectroscopy, X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, electron probe microanalysis, etc.

Journal of Materials Science Letters, 1989

Annals of Occupational Hygiene, 1994

Le Centre pour la Communication Scientifique Directe - HAL - memSIC, Nov 18, 2019

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The purpose of this report is to present a complete characterisation of tin oxide coatings, depos... more The purpose of this report is to present a complete characterisation of tin oxide coatings, deposited on soda-lime glass sheets for industrial applications, and to compare the results obtained by different techniques

Journal of Archaeological Science

The Great Umayyad Mosque of Damascus built between about 706 and 714/15 CE is the oldest survivin... more The Great Umayyad Mosque of Damascus built between about 706 and 714/15 CE is the oldest surviving mosque that still preserves large parts of its original architecture and decoration. The origins of the mosaic tesserae have been the subject of debate for more than a thousand years. The earliest sources written two centuries after the construction of the edifice claim a Byzantine origin of both, the material as well as the craftsmen. Here we use the compositional analyses of nearly 1,000 glass tesserae to show that 65% of the samples (80% of the coloured tesserae) from the mosque have a consistent chemistry and, by inference, originate from a common geographical source. Comparison with chemical data of early Islamic glass groups conclusively identifies Egypt as the origin of these tesserae and demonstrates that they are coeval with the foundation of the mosque. Additionally, the compositional features of the gold leaf tesserae testify to the systematic recycling and reuse of older material. Our findings suggest that the manufacture and supply of glass tesserae for the Great Mosque was a direct commission from the highest echelons of government.