Modeling and Sizing of a Fuel Cell—Lithium-Ion Battery Direct Hybridization System for Aeronautical Application

Nowadays, many aircraft manufacturers are working on new airplanes to reduce the environmental footprint and therefore meet greenhouse gas reduction targets. The concept of more electric aircraft is one of the solutions to achieve this goal. For this aircraft architecture, several electrical devices are used in order to supply propulsive and non-propulsive functions. This paper focuses on the sizing of a direct hybridization system to supply a non-propulsive function in an aircraft. It is composed of a High-Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC) and a lithium-ion (Li-ion) battery. This sizing is based on a static model of each storage device. The accuracy of these models is compared with dynamic models during a simulation for an aeronautical mission. Static models are implemented in a genetic algorithm to achieve two goals: on the one hand, satisfy the mission profile, and on the other hand, minimize the mass of the system. Other criteria, such as battery and fuel cell aging estimation, are considered. The obtained results show that the direct hybridization system allows protecting the fuel cell against an accelerated aging.

Heat Generation by Electrical Current in a Quantum Dot Hybridized to Majorana Nanowires

Heat current generated by electronic transport through a quantum dot (QD) coupled to both a phonon bath and a Majorana nanowire hosting Majorana bound states (MBSs) is theoretically studied in the framework of non-equilibrium Green’s function technique. The calculated numerical results show that electrical current can be either enhanced or suppressed by the combined influences of the phonon bath and the MBSs at certain bias voltage regimes. The enhancement and suppression of the current’s magnitude for a fixed bias voltage will be reversed due to the direct hybridization between the MBSs. The simultaneous coupling between both MBSs will amplify the function of the MBSs on the current, with the same unchanged and essential qualitative impacts. Heat generation by the electrical current can be fully adjusted by the dot–MBS coupling, direct hybridization between the MBSs, and positions of the dot level. By properly choosing the above parameters, heat generation can be suppressed even for increased electrical current, which is favorable in removing waste heat generated by electrical current flowing through low-dimensional circuits.

Direct fuel cell—supercapacitor hybrid power source for personal suburban transport

<abstract> <p>In view to proposing an alternative to oversized energy sources currently installed in electric vehicles for suburban transport, a direct hybrid fuel cell (FC)-supercapacitors (SC) source has been designed and tested on a test bench. The rated 15.6 kW source—with an air-cooled 5.6 kW FC and a 165 F SC storage device—was shown perfectly suited to traction of a 520 kg vehicle along the NEDC cycle, then validating the previously developed concept of a one-ton car propelled by a 10 kW FC in the rated 30 kW hybrid source for this cycle. In comparison with a FC used alone, hybridization was shown to allow the power demand for the cell to vary in quite a narrower range, as formerly observed. Moreover, the rates of fuel cell voltage and current generated in the driving cycle, were shown to be reduced by one order of magnitude by the direct hybridization which is to contribute to the FC durability. Two operating parameters were shown to have a significant effect on the hybrid source efficiency, namely the capacity of the SC at 110 or 165 F, and the recovery of deceleration power—emulated by an external power supply—which can decrease by 25% the fuel consumption in NEDC cycle conditions, as predicted by the model.</p> </abstract>

Development and characterization of Triticum turgidum – Aegilops comosa and T. turgidum – Ae. markgrafii amphidiploids

Aegilops comosa and Ae. markgrafii are diploid progenitors of polyploidy species of Aegilops sharing M and C genomes, respectively. Transferring valuable genes/traits from Aegilops into wheat is an alternative strategy for wheat genetic improvement. The amphidiploids between diploid species of Aegilops and tetraploid wheat can act as bridges to overcome obstacles from direct hybridization and can be developed by the union of unreduced gametes. In this study, we developed seven Triticum turgidum – Ae. comosa and two T. turgidum – Ae. markgrafii amphidiploids. The unreduced gametes mechanisms, including first-division restitution (FDR) and single-division meiosis (SDM), were observed in triploid F1 hybrids of T. turgidum – Ae. comosa (STM) and T. turgidum – Ae. markgrafii (STC). Only FDR was observed in STC hybrids, whereas FDR or both FDR and SDM were detected in the STM hybrids. All seven pairs of M chromosomes of Ae. comosa and C chromosomes of Ae. markgrafii were distinguished by fluorescent in situ hybridization (FISH) probes pSc119.2 and pTa71 combinations with pTa-535 and (CTT)12/(ACT)7, respectively. Meanwhile, the chromosomes of tetraploid wheat and diploid Aegilops parents were distinguished by the same FISH probes. The amphidiploids possessed specific valuable traits such as multiple tillers, large seed size related traits, and stripe rust resistance that could be utilized in the genetic improvement of wheat.

Direct hybridization gap from intersite and onsite electronic interactions in CeAg2Ge2

Electronic and crystal structure studies are presented to describe the role of intersite and onsite interactions for the itinerant electron magnetism in CeAg2Ge2.Magnetovolume effect and hybridization gap opening have been observed at low temperature.