Preliminary data on terrestrial isopods from some railways in Dobruja, eastern Romania

In July 2020 we analyzed the terrestrial isopod assemblages from different (mostly abandoned) railway constructions in Dobruja, eastern Romania. We identified 10 terrestrial isopod species, of which the most abundant and frequent were Porcellionides pruinosus (Brandt, 1833) and Armadillidium vulgare Latreille, 1804. We identified species that, in Romania, are present only in Dobruja: Leptotrichus pilosus Dollfus, 1905 and Trachelipus squamuliger (Verhoeff, 1907). Most of the species are common, generalist or synanthropic, connected to dry and open habitats. In abandoned railway-stations the number of species/samples was low (at most two), but at the base of a stone railway bridge in Babadag forest six species were found.

EXPERIMENTAL INVESTIGATION OF BIONIC SOIL-ENGAGING BLADES FOR SOIL ADHESION REDUCTION BY SIMULATING ARMADILLIDIUM VULGARE BODY SURFACE

Soil adhesion is a physical phenomenon which results in undesirable effects including increment in drag force and energy consumption of cutting or tillage tools. One method to reduce the soil adhesion is biomimetics, i.e., focusing on the technique soil-burrowing animals’ benefit. In this study, three types of blade were designed and built: flat blade, corrugated blade and a combination of flat and corrugated blades. The corrugated blade was simulated from Armadillidium vulgare body surface geometrical shape. Experimental results showed that in dry soil, flat and corrugated blades required similar drag force while the combined blade showed higher drag force requirements. In wet soil, the corrugated blade resulted in the lowest drag force, which was due to faster movement of soil layer on the blade surface. Drag force of the corrugated blade was lower than the half of the drag force of two other blades at travel speed of 0.04 m/s. Besides, the drag force of corrugated blade decreased by increasing the blade travel speed. Furthermore, in wet soil, the energy consumption of the corrugated blade at the travel speeds of 0.02 and 0.04 m/s was 66% and 83% lower than the flat blade, respectively.