Les nouveaut s en technique de pulv risation

SIGLEBSE B706833W / UCL - Université Catholique de LouvainBEBelgiu

The Mobile control of crop sprayers.

A successful spray application doesn't only depend on the choice of the appropriate chemical product and on the treatment period, but also depends on the user's abilities and the working order of the crop sprayer. The experience shows that these two points often pose a problem. Concerning the equipment, many countries have taken initiatives for the sprayers control. This one is usually free but the tendance is to make it obligatory. The control method implemented in Belgium (Wallon region) is different from the general method based on the use of a spray pattern collector: it is completely mobile and is essentially based on the measure of the pressure at the boom and of the nozzles output. The results show that many sprayers are not in a good working order.La réussite d’un traitement phytosanitaire est liée au choix judicieux du produit de traitement et de sa période d’application, ainsi qu’à la compétence de l’utilisateur et à l’état du pulvérisateur employé. L’expérience montre que ces deux points posent souvent problème. En ce qui concerne le matériel, de nombreux pays ont pris des initiatives au niveau du contrôle des pulvérisateurs. Celui-ci est généralement libre mais évolue vers un caractère obligatoire. La procédure de contrôle développée en Belgique (Région Wallonne) diffère de la méthodologie générale qui fait usage d’un banc répartiteur. Elle est complètement mobile et se base essentiellement sur des mesures de pression au niveau de la rampe ainsi que de débits des buses. Les résultats acquis montrent que bon nombre des pulvérisateurs ne sont pas en parfait état de fonctionnement

Survey of Channel and Radio Propagation Models for Wireless MIMO Systems

This paper provides an overview of the state-of-the-art radio propagation and channel models for wireless multiple-input multiple-output (MIMO) systems. We distinguish between physical models and analytical models and discuss popular examples from both model types. Physical models focus on the double-directional propagation mechanisms between the location of transmitter and receiver without taking the antenna configuration into account. Analytical models capture physical wave propagation and antenna configuration simultaneously by describing the impulse response (equivalently, the transfer function) between the antenna arrays at both link ends. We also review some MIMO models that are included in current standardization activities for the purpose of reproducible and comparable MIMO system evaluations. Finally, we describe a couple of key features of channels and radio propagation which are not sufficiently included in current MIMO models