An improved reconstruction procedure for the correction of local magnification effects in three-dimensional atom-probe

A new 3DAP reconstruction procedure is proposed that accounts for the evaporation field of a secondary phase. It applies the existing cluster selection software to identify the atoms of the second phase and, subsequently, an iterative algorithm to homogenise the volume laterally. This Procedure, easily implementable on existing reconstruction software, has been applied successfully on simulated and real 3DAP analyses

Gestion de l’incertitude dans une portion originale du paysage sacré gallo-romain: les sanctuaires des eaux

The study of water cults in Gaul suffers not only from a great deal of variability in the quality of the available data, which is a common issue in archaeology, but also, more specifically, from the burdening of past historiographical approaches, which contributed to conveying a distorted view of the phenomenon. Accordingly, our main problems lie in site identification and reliability assessment. Until recently this uncertainty was avoided by widening the study to all sites with at least one characteristic attribute, or conversely, by limiting the corpus to the best documented sites. It seemed necessary to develop tools that would exploit this uncertainty, to study the phenomenon in the most complete possible way. These tools take the form of a database, associated with a GIS, leading to the practical evaluation of a site potential using a calculation grid

Nanostructure and properties of a Cu-Cr composite processed by severe plastic deformation

A Cu-Cr composite was processed by severe plastic deformation to investigate the role of interphase boundaries on the grain size reduction mechanisms. The as-deformed material exhibits a grain size of only 20nm. This gives rise to a dramatic increase of the hardness. Some deformation induced Cu super saturated solid solutions were clearly exhibited and it is shown that they decrease the hardness. The formation of such supersaturated solid solution and their influence on the mechanical properties are discussed

Aspectus: A flexible collaboration tool for multimodal and multiscalar 3D data exploitation.

High density remote survey technologies have become widespread practices. In recent years, we have seen a tenfold increase in volume of digital data acquired. Beyond this sheer amount of data, multimodal three-dimensional data exploitation has become another common challenge for specialists. The Aspectus project aims to ease the access to complex three-dimensional data and to promote collaborative work and remote expert assessment. Thus, we can get past the problem of distance and availability of the “object of expertise”, ranging from cultural heritage sites to artefacts. By extension, it enables us to circumvent the ever-present problem of destruction. Aspectus takes advantage of available open source solutions to produce a flexible web-based visualization and collaboration tool. After an overview of the theoretical framework and its technical implementation, we will discuss a practical application as part of the “Bibracte Numérique” project

Aspectus : développement d’une plateforme collaborative en ligne d’analyse des données 3D pour l’archéologie et le patrimoine

Le projet Aspectus a été engagé en 2016 afin de répondre à des besoins récurrents émanant de programmes de recherche en archéologie. En effet, la place croissante des données numériques nous oblige à élaborer de nouvelles stratégies pour gérer, intégrer et disséminer un volume exponentiel d’informations complexes, multimodales et multirésolution, en direction d’utilisateurs aux attentes et aux compétences variées. Paradoxalement, ces données deviennent de plus en plus difficiles à exploiter par des non-spécialistes. Notre objectif est donc de faciliter le partage de ces données entre tous les acteurs scientifiques en leur donnant les moyens de les visualiser, de les analyser et de les interpréter sans que cela exige une maîtrise technique avancée. Aspectus prend la forme d’un outil en ligne fondé sur des technologies open-source et rend accessibles des données 3D complexes à l’aide d’un navigateur web. Le système s’appuie pour cela sur une interface communautaire qui promeut le partage, la collaboration et l’expertise à distance. Suite au vif intérêt suscité par la présentation d’un « proof of concept » au salon Innovative SHS 2017, il semble désormais opportun de poursuivre le développement de l’outil sous la forme d’un prototype. Dans cette perspective, le projet a maintenant pour cadre le groupe de travail réuni par le projet « Bibracte numérique » qui vise à développer une chaîne de traitement numérique de l’information appliquée aux métiers de l’archéologie.The Aspectus project was born out of necessity some years ago, during a post-excavation season. In recent years, we have seen a tenfold increase in the volumes of digital data acquired. This phenomenon of increasing digitisation in the field of archaeology, and of cultural heritage more generally, requires strategies for managing an inordinate quantity of 3D data and making it available to a broad array of researchers and an even broader public audience. Beyond the sheer quantity of data, multimodal and multiresolution data exploitation has become another common challenge. The Aspectus project aims to facilitate access to complex three-dimensional data and to promote collaborative work and remote expert assessment. Aspectus takes advantage of available open-source solutions to produce a comprehensive software solution that encompasses multiple complementary approaches: high quality 3D web visualisation, data analysis and annotation tools, online workplace platform, in other words, making complex 3D data accessible and available for analysis in a collaborative environment. Our first trial concept generated much interest at the Innovative SHS 2017 exhibition and we are now developing a prototype of Aspectus as part of the “Bibracte Numérique” project

A model to predict image formation in the three-dimensional field ion microscope

This article presents a numerical model dedicated to the simulation of field ion microscopy (FIM). FIM was the first technique to image individual atoms on the surface of a material. By a careful control of the field evaporation of the atoms from the surface, the bulk of the material exposed, and, through a digitally processing a sequence of micrographs, a three-dimensional reconstruction can be achieved. 3DFIM is particularly suited to the direct observation of crystalline defects such as vacancies, interstitials, vacancy clusters, dislocations, and any combinations of theses defects that underpin the physical properties of materials. This makes 3DFIM extremely valuable for many material science and engineering applications, and further developing this technique is becoming crucial. The proposed model enables the simulation of imaging artefacts that are induced by non-regular field evaporation and by the impact of the perturbation of the electric field distribution of the distorted distribution of atoms close to defects. The model combines the meshless algorithm for field evaporation proposed by Rolland et al. (Robin-Rolland Model, or RRM) with fundamental aspects of the field ionization process of the gas image involved in FIM