Search results for "Craft"
showing 10 items of 369 documents
Space-VLBI phase-reference mapping and astrometry
2001
We present 5 GHz space-VLBI observations of the quasar pair B1342+662/B1342+663 that demonstrate the feasibility of phase-reference techniques using an antenna in space. The space-based data were taken by the satellite HALCA, of the space-VLBI mission VSOP. From residual (referenced) phases we derive an upper bound of 10 meters to the uncertainty of the spacecraft orbit reconstruction. An analysis of the phase-reference maps of the sources additionally suggests that the above mentioned uncertaintyis likely not larger than 3 meters. With errors of this magnitude, HALCA is a useful tool for astrometric studies of close pairs of radio sources.
Batteries for Aerospace: A Brief Review
2018
This paper presents a brief overview on batteries for aerospace application. In particular, More Electric Aircraft (MEA) and All Electric Aircraft (AEA) concepts are introduced at first, together with their main advantages and drawbacks. Subsequently, opportunities and issues related to the employment of batteries on aircrafts are presented and briefly discussed. Reference is then made to aircraft power system architectures and battery technologies, as well as on the state-of-the-art of battery management systems, state-of-charge and state-of-health estimations, and thermal management.
Beer tourism and craft beer
2021
International audience
A major shift in Late Bronze Age metalwork production around 900 BC
2023
Our traditional chronology systems hardly ever reflect cultural changes accurately and may even mask real moments of discontinuity. This is particularly true for the second part of the Late Bronze Age Urnfield Period where a radical change in iconography can actually be noticed around 900 BC. Within a very short period, the famous solar bird-boat iconography, which had widely developed over centuries and given rise to the elaborate and sophisticated ornamentation known on solid hilted swords from the 11th/10th century, takes a back seat and we can see a single new symbol coming to the fore, concentrating figurative representation in form of a singular vase-shaped build (Wirth S. 2021, 652-6…
Transmission patterns in the production of Bronze Age solid- hilted swords
2023
Bronze Age swords with a bronze hilt were a highly specialised production. Casting hilts and blades and fixing them to each other require lots of precision and very specific skills. We hardly know anything about the production organisation as moulds are extremely rare, preventing us from locating workshops. However, studying swords themselves using X-ray imaging techniques allows us to reconstruct a part of the chaîne opératoire and gain insight into some aspects of the production processes. We identify three periods in the production of solid-hilted swords at the European scale:1. Experimental phase (1800-1450 BC): small-scaled productions by multiple workshops experimenting various ways o…
Production et circulation des épées à poignée métallique de l'âge du Bronze en Europe occidentale
2022
Several regional syntheses have been published on Bronze Age solid-hilted swords, but none for France and the Benelux countries. This dissertation aims first at filling this gap by listing the swords from this region. By adding data from these pre-existing studies, it is possible to study the distribution of solid-hilted swords on a European scale. The building of an inventory is an essential condition to study the diffusion of these weapons over long distances. This must come along with models to characterise the organisation of the swords production and the ways they spread out. It requires us to question the status of the craftsmen, their organisation and their location. One of the first…
Friedel-Crafts Alkylation of Arenes in Total Synthesis
2015
ChemInform Abstract: Unexpected Formation of a 1,2-Dichloroacenaphthylene in a Friedel-Crafts Reaction with Chloral Hydrate.
2012
Unexpected Formation of a 1,2-Dichloroacenaphthylene in a Friedel-Crafts Reaction with Chloral Hydrate
2012
An unprecedented rearrangement was encountered during an attempted alkylation of an electron-rich naphthalene with chloral hydrate. The reaction produced a dichlorinated acenaphthylene and presumably involves the intermediate formation of a chloronium ion which is opened to produce the five-membered ring of the final product.