No abstract

Nowadays about 20% of the worldwide energy consumption is attributable to refrigeration almost based on vapor compression. In the scientific literature in the class of the eco-friendly cooling technologies alternative to vapour compression there is solid state cooling. In this field, the scientific community has devoted the attention specifically toward elastocaloric refrigeration. Elastocaloric refrigeration is based on the latent heat associated with the transformation process of the martensitic phase, found in Shape Memory Alloys (SMA) when they are subjected to uniaxial stress cycles of loading and unloading. SMAs are characterized by the mechanical property of being able to return to the initial form once the uniaxial stress has been removed. By exploiting this effect in a reverse regenerative thermodynamic cycle called Active elastocaloric regenerative refrigeration cycle (AeR), a satisfactory cooling effect is achievable. In this paper, the results of a numerical investigation conducted, through a 2-D model, on a single bunch of elastocaloric elements are shown. Specifically, the heat transfer and the energy performances are studied both by varying the geometrical parameters of the elements and by varying the auxiliary fluid (air) velocity.

The onion thrips, Thrips tabaci, is a main insect pest for many field crops worldwide, with a particular preference for the species of the genus Allium. Aeolothrips intermedius is a banded thrips, whose larvae are considered the primary native predator of T. tabaci. Due of their predatory behaviour, A. intermedius larvae are considered a good candidate for biological control against thrips pests. However, limited information is available on the specific predation rate of A. intermedius against T. tabaci. The aim of our study was to evaluate the predatory efficiency of A. intermedius larvae against T. tabaci adults. Predation assays, performed under laboratory conditions, indicated that A. intermedius larvae begin to prey after an average of about 23 min, and the time taken by an A. intermedius larva to capture and subdue the prey until its death is about 26 min. Furthermore, the maximum number of prey that the A. intermedius larvae are able to kill in 12 h is up to eight adults of T. tabaci/A. intermedius larva.