Rigorous analysis of a satellite antenna including its surrounding environment with the Dual-Grid FDTD method

International audienceThis paper presents a rigorous analysis of a satellite antenna mounted onto its platform using the Dual-Grid FDTD method. In the first step of the method, the isolated antenna is analyzed. The study of the surrounded antenna is carried out in the second step of the DG-FDTD method. The results obtained in this realistic test case show the significant influence of the environment over the antenna

Hybridation de la DG-FDTD avec l'optique physique fréquentielle pour l'analyse d'antennes sur porteur

National audienceCet article propose une nouvelle méthode hybride destinée à l'analyse du rayonnement, sur une large bande de fréquences, d'antennes présentant un environnement proche complexe et positionnées sur des structures électriquement grandes. On présente ainsi l'hybridation entre une méthode temporelle multi-échelle rigoureuse, la DG-FDTD (Dual Grid-FDTD), et une méthode asymptotique, l'optique physique fréquentielle. Afin d'illustrer les performances de cette méthode, on traite, dans la dernière partie de cet article, le cas d'une antenne placée sur un véhicule

Hybridization of the Dual-Grid FDTD with the Physical Optics to Analyze Antennas Mounted on Large and Complex Platforms

International audienceThis paper presents a new simulation strategy based on the hybridization of a fullwave time domain multi-scale method, the Dual-Grid FDTD (DG-FDTD), and the Physical Optics (PO). This new method aims at simulating antennas mounted on large conducting platforms and whose nearby surrounding environment is very complex. Typical application fields of the hybrid DG-FDTD/PO method are the computation of radiation patterns of antennas mounted on carriers such as satellites, ships, aircraft and land vehicules

Analysis of Surrounded Antennas Mounted on Large and Complex Structures Using a Hybrid Method

International audienceA new hybrid method, the DG-FDTD/IPO, has recently been proposed to analyze surrounded antennas mounted on large platforms. In this paper the capabilities of this method to go through such large and complex problems are shown. More precisely, a deep analysis of the far-field radiated for a canonical antenna-on-platform scenario is proposed

A new hybrid method for the analysis of surrounded antennas mounted on large platforms

International audienceAn efficient technique to provide fast and accurate analysis of wide-band surrounded antennas mounted on electrically large platforms is presented and validated in this paper. The hybrid method combines Dual-Grid FDTD (DG-FDTD) with Iterative Physical Optics (IPO) to analyze on-platform antenna radiation. In section IV of this paper, DG-FDTD/IPO is applied to the analysis of a wide-band antenna mounted on a vehicle. The ability to address the problem of antenna placement is also demonstrated

Identification and characterization of an endogenous chemotactic ligand specific for FPRL2

Chemotaxis of dendritic cells (DCs) and monocytes is a key step in the initiation of an adequate immune response. Formyl peptide receptor (FPR) and FPR-like receptor (FPRL)1, two G protein–coupled receptors belonging to the FPR family, play an essential role in host defense mechanisms against bacterial infection and in the regulation of inflammatory reactions. FPRL2, the third member of this structural family of chemoattractant receptors, is characterized by its specific expression on monocytes and DCs. Here, we present the isolation from a spleen extract and the functional characterization of F2L, a novel chemoattractant peptide acting specifically through FPRL2. F2L is an acetylated amino-terminal peptide derived from the cleavage of the human heme-binding protein, an intracellular tetrapyrolle-binding protein. The peptide binds and activates FPRL2 in the low nanomolar range, which triggers intracellular calcium release, inhibition of cAMP accumulation, and phosphorylation of extracellular signal–regulated kinase 1/2 mitogen-activated protein kinases through the Gi class of heterotrimeric G proteins. When tested on monocytes and monocyte-derived DCs, F2L promotes calcium mobilization and chemotaxis. Therefore, F2L appears as a new natural chemoattractant peptide for DCs and monocytes, and the first potent and specific agonist of FPRL2

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

A new method for rapeseed hulls purification – Proof of concept

The loss of fats in the hulls is one of the main obstacles limiting the industrial implementation of rapeseed dehulling. The main reason resides in the shape of rapeseed outer cotyledons which resemble to the hulls’ shape and make it difficult to separate. The purpose of this study is to propose a new method for the purification of rapeseed hulls. After primary separation by aspiration, the mixture of hulls and kernels is passed between a pair of flat rolls where kernels are flattened and stick to the metal while the hulls do not. We exploited this property to adapt a small laboratory flaker with two counter-rotating cylinders of 65 mm diameter with scrapers that make the kernels fall away from the hulls. Process optimization by tunning experimental conditions (hulls moisture content, roller spacing, roller speed and feed rate) allowed the determination of the optimal operating conditions. Experiments showed that wetting improves the purity of the hulls but reduces the one of the recovered kernels. A gap of 0.1 mm was necessary. In addition, it was shown that the sorting quality depends on the ratio flow-rate / rotation-speed. The best performances are reached around 1 g.s−1.rpm−1. In these conditions, the hulls and kernels purity were 96% and 94% respectively. This preliminary work has allowed us to prove the concept. The next step will be to develop a pilot plant to validate the process efficiency on a larger scale (100 kg/h)

Hybridation de la Dual-Grid FDTD avec l'optique Physique itérative pour l'analyse d'antennes sur porteur

National audienceCet article propose une nouvelle méthode hybride destinée à l'analyse du rayonnement, sur une large bande de fréquences, d'antennes présentant un environnement proche complexe et positionnées sur des structures électriquement grandes. On présente ainsi l'hybridation entre une méthode temporelle multi-échelle rigoureuse, la DG-FDTD (Dual Grid-FDTD), et une méthode asymptotique fréquentielle, l'optique physique itérative

Analysis of surrounded antennas: from DG-FDTD to DG-FDTD/IPO

International audienc