Liebherr (France)

The propulsion system architectures of all-electric aircraft often rely on multiple energy sources, in particular hydrogen-based fuel cells and batteries, to accommodate varying power demands throughout a mission profile. In this study, the source-side architecture for electric aircraft propulsion was investigated, focusing on the integration with power management and distribution systems. A two-port configuration with dual active bridge converters and a multi-port topology utilizing a triple active bridge converter were compared. Through the analysis of a hydrogen-based regional aircraft mission profile, the performance of each converter was assessed for the relevant mission phases. The topologies were evaluated in terms of efficiency, power density and control complexity. Semiconductor and transformer losses were calculated to assess system efficiency, utilizing thermal models and analytical methods. An existing sizing approach was extended to include transformer design, enabling the evaluation of volumetric and gravimetric power density. The preliminary design results in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$22.7 \text{kW} / \text{kg}$</tex> for the three-port architecture, which is slightly higher than the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$21.9 \text{kW} \text{kg}$</tex> for the two-port architecture. Depending on the mission phase, either the dual active bridge or the triple active bridge would be more advantageous. Additionally, complexity and control considerations for the evaluated converter systems were addressed in this paper, offering insights into the key characteristics and trade-offs for electric aircraft propulsion concepts.

Naturalist divers have built D.O.R.I.S. for « Données d’Observations pour la Reconnaissance et l’Identication de la faune et de la flore Subaquatiques », an open-source website dedicated to marine species, accessible to anyone, and notably to divers.This site is run by a community of validators- moderators, who are in contact with academic researchers for expert assessments. This website prently contains 3090 species pages, 19 different habitats, 2849 definitions in specific glossary, 129 965 messages on a friendly-used forum, 1089 contributors.The information and illustrated pictures provide keys for identifying species at different levels: for individual divers or scientists, macro (and often micro) biological characteristics, geographical distribution, nomenclature of clades in line with the latest phylogenetic advances, etc.D.O.R.I.S. exists from 2004, its incremental version V4 since 2015, thanks due to « Commission Nationale Environnement et Biologie Subaquatiques » (CNEBS) de la « Fédération Française d’études et de Sports Sous-Marins » (ffessm.fr). At the end of 2014, in addition to federal financial support, DORIS received help from a major new partner, the « Agence des Aires Marines Protégées » (AAMP).Participatory science represents a huge field of observations that can help academic research, thanks to the thousands of divers scattered around the world's subtidal zones. DORIS is a perfect example of an interactive contribution, covering the French coastline, mainland France and overseas, as well as some more exotic locations, such as the Red Sea or the Pacific destinations frequented by French-speaking divers.Education and public awareness are key to preserving the marine environment, and participatory science has an undeniable role to play in a sustainable future.Our aim here is to present the D.O.R.I.S. website at One Ocean Conference, to promote interactions between academic and non-academic players, and to develop its visibilty to all the partners.visit our site at: https://doris.ffessm.fr/

Ionospheric scintillations due to ionosphere irregularities may severely degrade GNSS data in equatorial and high latitudes regions, and consequently the applications that rely on such data. It is thus of high importance for many users in a large variety of applications to have access to global maps of scintillation intensity, for both signal phase and amplitude. Typically, networks of ground based GNSS receivers are used to derive those maps, but it inevitably leads to sparse coverage.&amp;#160;In order to mitigate this weakness, the current study proposes to add original data points based on the DORIS system. DORIS (Doppler Orbitography by Radiopositioning Integrated by Satellite) is a French orbitography system, developed primarily for altimetric purposes by the Centre National d&amp;#8217;Etudes Spatiales (CNES), the Institut National de l&amp;#8217;information g&amp;#233;ographique et foresti&amp;#232;re (IGN) and the Groupe de Recherche de G&amp;#233;od&amp;#233;sie Spatiale (GRGS). It consists of a network of around sixty ground-based beacons emitting a radio-frequency signal at 400 MHz and 2 GHz. The on-board receivers (on 9 civilian satellites as of January 2024) then performs Doppler shift measurements that allow precise orbit determination.&amp;#160;&amp;#160;Despite a lower data rate (0,1 Hz instead of 1 Hz for the GNSS) and a lower number of satellites, DORIS can add valuable information where there is no GNSS receivers, or by taking advantage of its geometry, in particular with polar satellites. In this study, we will explore to what extent it is possible to define scintillation proxies based on DORIS data losses, phase signal degradation, or power signal attenuation, by a comparison to a scintillation data base from GNSS measurements. Eventually, we will discuss whether the challenging near-real time basis delay is achievable.&amp;#160;

Since first introduced by Robert Bosch GmbH in 1980s, the Controller Area Network (CAN) bus showed good success and capability of working reliably, even in harsh environments. Multiple other sectors were seduced by the CAN-bus achieved role and importance in automotive industry. For instance in avionics, Airbus first introduced it on the A318 and A340 for cabin ventilation system control [1], and this usage keeps on increasing, specially with the focus on reducing the harness mass and complexity. For the same purpose, the interest to employ Power Line Communication (PLC) technology for airborne application is gaining ground in the frame of the More Electric Aircraft (MEA) or even an All-Electric Aircraft (AEA) architectures. Combining both technologies can reach a higher impact on reducing the cabling weight, complexity and space allocation. This paper explores a real-case context feasibility to implement CAN-bus protocol along with PLC technology over aircraft dc power line, with respect to CAN-bus aspects, PLC principals and aeronautic standard compliance. Comprehensive CAN-PLC tests and assessment were carried out, analysing latency, Bit-Error Rate (BER) and Electromagnetic Compatibility (EMC) in alignment with the RTCA DO-160G standard requirements.

This paper proposes a stability analysis procedure of fluid power components according to some early design parameters. It is based on the numerical determination of the existence of a Lyapunov function, which guarantees the required performance. This is formulated as an optimization problem under Linear Matrix Inequalities constraints (LMIs). The model-based procedure is illustrated with an application to a pneumatic two-stage pressure regulation valve. The results show the method capability to provide a better understanding of the possible causes of the valve’s instability and how it can be avoided at an early design stage by tuning the physical parameters in order to guarantee a desired dynamical behavior and improve system robustness.

Abstract No abstract.

In diesem Beitrag wird anhand konkreter Beispiele aus der Praxis aufgezeigt, wie Gender- und Diversitatsaspekte bzw. -themen mit Aufstellungsarbeit sichtbar gemacht und bearbeitet werden konnen. Dafur werden die Begriffe Gender und Diversity erlautert und zur Aufstellungsarbeit in Beziehung gesetzt. Am Beispiel von konkreten Prozessen werden Gender und Diversity als explizite Themen, Kriterien oder als implizite Einflussfaktoren dargestellt und diskutiert. Den Abschluss bilden Anregungen fur eine gender- und diversitatssensible psychodramatische Organisationsaufstellungsleitung.

Radial turbines’ preliminary designs are usually carried out through some dimensionless approaches, such as the loading-to-flow-diagram and/or the blade speed ratio. In case of variable nozzle radial turbines, multi-points specifications must be considered, related to the improvement of the operating range. As preliminary design correlations and standards usually taken into consideration arise from studies dedicated to fixed geometry radial turbines, they need to be updated with regard to nozzle off-design opening configurations. This paper provides some theoretical basics in order to help designers considering variable geometry problems. Some complementary elements about the dimensionless methods are given by taking into account the nozzle opening effect. Then, useful considerations are brought regarding the preliminary design of variable geometry radial turbines with multi-points specifications.