Micromagnetic simulations are used to investigate the motion of magnetic skyrmions in an in-plane strain gradient. The skyrmion diameter and energy are found to depend on the strain, which leads to a force that moves the skyrmion toward regions with higher strain. An analytical expression for the skyrmion velocity as a function of the strain gradient is derived assuming a rigid profile for the skyrmion, and good agreement with simulations is obtained. Furthermore, electromechanical simulations of a hybrid ferromagnetic/piezoelectric device show that the in-plane strain gradients needed to move skyrmions can be achieved by applying moderate voltages in the piezoelectric substrate, which offers an original way to control skyrmion motion efficiently.

Sea urchins possess specialized adhesive organs, tube feet. Although initially believed to function as suckers, it is currently accepted that they rely on adhesive and de-adhesive secretions to attach and detach repeatedly from the substrate. Given the biotechnological potential of their strong reversible adhesive, sea urchins are under investigation to identify the protein and glycan molecules responsible for its surface coupling, cohesion and polymerization properties. However, this characterization has only focused on a single species, Paracentrotus lividus. To provide a broader insight into sea urchins adhesion, a comparative study was performed using four species belonging to different taxa and habitats: Diadema africanum, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. Their tube feet external morphology and histology was studied, together with the ultrastructure of their adhesive secretory granules. In addition, one antibody and five lectins were used on tube foot histological sections and extracts, and on adhesive footprints to detect the presence of adhesion-related (glyco)proteins like those present in P. lividus in other species. Results confirmed that the antibody raised against P. lividus Nectin labels the adhesive organs and footprints in all species. This result was further confirmed by a bioinformatic analysis of Nectin-like sequences in ten additional species, increasing the comparison to seven families and three orders. The five tested lectins (GSL II, WGA, STL, LEL, and SBA) demonstrated that there is high interspecific variability of the glycans involved in sea urchin adhesion. However, there seems to be more conservation among taxonomically closer species, like P. lividus and S. granularis. In these species, lectin histochemistry and lectin blots indicated the presence of high molecular weight putative adhesive glycoproteins bearing N-acetylglucosamine residues in the form of chitobiose in the adhesive epidermis and footprints. Our results emphasize a high selective pressure for conservation of functional domains in large putative cohesive proteins and highlight the importance of glycosylation in sea urchin adhesion with indications of taxonomy-related conservation of the conjugated glycans.

Abstract:The aim of the paper is to present the battery equivalent circuit for electric vehicle application. Moreover, the model described below is dedicated to lithium-ion types of batteries. The purpose of this paper is to introduce an efficient and transparent method to develop a battery equivalent circuit model. Battery modeling requires, depending on the chosen method, either significant calculations or a highly developed mathematical model for optimization. The model is evaluated in comparison to the real data measurements, to present the performance of the method. Battery measurements based on charge/discharge tests at a fixed C-rate are presented to show the relation of the output voltage profiles with the battery state of charge. The pulse discharge test is presented to obtain the electric parameters of the battery equivalent circuit model, using a Thévenin circuit. According to the Reverse Trike Ecologic Electric Vehicle (VEECO RT) characteristics used as a case study in this work, new values for vehicle autonomy and battery pack volume based on lithium nickel manganese cobalt oxide cells are evaluated.