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Fatigue assessment of mechanical components can be very challenging due to the presence of macroscopic defects and notches. However, local approaches as the Stain Energy Density, have shown how the fatigue resistance is strictly related to the local stress field near the notch tip and not on the overall dimensions of the component. It is necessary to know some peculiar material’s parameters to apply those local approaches. A short way to obtain such parameters can be to apply Thermographic Methods, such as the Risitano’s Thermographic Method and the Static Thermographic Method, monitoring the energy release during stepwise fatigue and static tensile tests. In this work, experimental tests were performed on plain and double edge steel notched specimens. The SED method has been applied through finite element models, with the easy application of the volume-free procedure, to evaluate its trend at several stress levels. The analysis of the energy release and of the local averaged strain energy density during a static tensile test may be adopted as a novel approach to relate the local stress state with a macroscopic stress value that introduce in the material the first micro plasticization leading to the failure of the component.

Abstract: A hobo-related sequence, Cchobo, with high similarity to the Drosophila melanogaster HFL1 and hobo108 elements was isolated from the medfly. Thirteen PCR-derived clones, which share 97.9–100% DNA identity, were sequenced, seven of which do not show frame-shift or stop codon mutations in their conceptual translations. The consensus sequence has 99.7% DNA identity with the D. melanogaster hobo element HFL1. In a phylogenetic analysis with other hobo-related elements, Cchobo clusters with the HFL1 and hobo108 elements from D. melanogaster and hobo-related elements from D. simulans, D. mauritiana and Mamestra brassicae. These elements may have undergone horizontal transfer in the recent past. The genomic distribution of Cchobo was studied by FISH to mitotic and polytene chromosomes, which revealed that Cchobo is distributed within both the heterochromatin and euchromatin. Intra- and interstrain polymorphisms were detected both at euchromatic and heterochromatic sites. These findings suggest that active copies of the element may be present in the medfly genome.

With the goal of understanding the electron transfer mechanism of fluorophore-functionalized pillararenes, a pillar (Zhang et al., 2018) [5]arene bearing two dansyl fluorophore moieties at the opposite rims of its cavity has been synthesized, and the behavior of such a new host molecule has been thoroughly investigated in the presence of an N,N′-di (6-bromohexyl)-viologen derivative. 1H NMR, NOESY and DOSY experiments demonstrated that the pillar (Zhang et al., 2018) [5]arene recognizes the viologen derivative, forming a 1:1 host-guest complex by including one of the two bromoalkyl chains within its π-rich cavity. Photophysical and electrochemical studies revealed that, upon guest addition to the host, the fluorescence intensity of the complex is progressively quenched by a photoinduced electron transfer process (PET) from one of the dansyl groups of the host to the viologen moiety of the guest.