86,879 research outputs found
Structural, catalytic and electrical investigation on La1-xSrxCr1-yFeyO3- δ as anodes for IT-SOFCs
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First hint on a change of the Po-210 alpha-decay half-life in the metal Cu
No full textIn the metal Cu cooled to T = 12K the alpha-decay half-life of Po-210 nuclides, located inside the metal, was measured to be shorter by 6.3 +/- 1.4% compared to that at room temperature. RI Aliotta, Marialuisa /H-2567-201
Brillouin scattering investigations of liquid crystal ME6N/CCl4 mixtures
No full textWe present the results of a Brillouin scattering experiment performed on mixtures composed by a thermotropic liquid crystal, ME6N (4-cyanophenyl-4’-hexylbenzoate) and carbon tetrachloride. Recently, we showed1 how the excess thermodynamic properties observed in some binary mixtures are mainly originated by excluded volume effects. Within this scenario some thermodynamic properties of the mixture can be successfully described using a primitive model based on hard sphere potential with non-additive diameters.
ME6N/CCl4 system represents a good experimental test-bed for extending this approach to mixtures with elongated molecules. To this purpose we have compared the experimental adiabatic compressibility and the excess volumes with the theoretical predictions obtained by using as a model a mixture composed by elongated and spherical particles interacting through a hard-core potential
Brillouin scattering investigation of ME6N liquid crystal in CCl4
No full textSome experimental Brillouin scattering measurements have been performed on binary mixtures composed by a liquid crystal immersed in a non polar solvent. The experimental compressibility has been fitted using a theoretical approach based on a hard-core model whose reliability has been successfully checked for many binary mixtures of molecular liquids. In this article we generalize this apparently naïve approach to the case where the molecular shape of one of two involved species is elongated. The agreement with experimental results seems to support our leading idea that the compressibility behaviour is mainly driven just by excluded volume interactions
New synthetic strategies for the enhancement of the ionic conductivity in Ce0.8Sm0.2O2-x
No full textHelium burning and neutron sources in the stars
No full textHelium burning represents an important stage of stellar evolution as it contributes to the synthesis of key elements such as carbon, through the triple-α process, and oxygen, through the 12C(α,γ)16O reaction. It is the ratio of carbon to oxygen at the end of the helium burning stage that governs the following phases of stellar evolution leading to different scenarios depending on the initial stellar mass. In addition, helium burning in Asymptotic Giant Branch stars, provides the two main sources of neutrons, namely the 13C(α,n)16O and the 22Ne(α,n)25Mg, for the synthesis of about half of all elements heavier than iron through the s-process. Given the importance of these reactions, much experimental work has been devoted to the study of their reaction rates over the last few decades. However, large uncertainties still remain at the energies of astrophysical interest which greatly limit the accuracy of stellar models predictions. Here, we review the current status on the latest experimental efforts and show how measurements of these important reaction cross sections can be significantly improved at next-generation deep underground laboratories
Extracellular vesicles in multiple sclerosis as possible biomarkers: Dream or reality?
No full textExtracellular vesicles are recently described as specialized structures for intercellular communication. Their role in the central nervous system was diffusely studied in both physiological and pathological condition. In particular, an increased extracellular vesicle number was detected in several autoimmune diseases, including multiple sclerosis, a chronic autoimmune, inflammatory, demyelinating and neurodegenerative disease. This chapter summarizes the available information on the involvement of the extracellular vesicles in multiple sclerosis pathogenesis and their possible use as biomarker of therapy efficac
Thermal, Mechanical and Micromechanical Analysis of PLA/PBAT/POE-g-GMA Extruded Ternary Blends
No full textIn order to toughen Poly(lactic) acid and binary blends with low PBAT content while maintaining a high biodegradability of the final material, poly(lactic) acid (PLA)/poly(butylene-adipate-co-terephthalate) (PBAT)/ polyolefin elastomer grafted with glycidyl methacrylate (POE-g-GMA) extruded ternary blends have been investigated in this work from a thermal, mechanical, and rheological point of view. The two elastomers have been added in different amounts as dispersed phases into the PLA matrix, paying attention to the final objective: the design of a 90% biodegradable formulation according to EN 13432. These ternary blends exhibited improved impact properties but still low elongation at break. Consequently, to the ternary composition with the best compromise of PLA quantity, biodegradability and thermo-mechanical properties (81 wt.% PLA, 9 wt.% PBAT, and 10 wt.% POE-g-GMA) a small quantity (10 wt.%) of a biobased plasticizer was added in order to further increase the impact properties in parallel with the tensile flexibility. Two types of plasticizers were investigated, one not reactive [Acetyl Tributyl Citrate (ATBC)], and one reactive [Glycidyl ether (EJ-400)]. A micromechanical study, in order to investigate the toughening mechanism of these systems, was carried out on the final formulations. They were also examined by dilatometric tests and elasto-plastic fracture mechanics correlating the data obtained to the morphology and to the rheological properties. In conclusion, the best compromise between impact, tensile properties and biodegradability content was achieved using the reactive plasticizer (EJ-400) whose interaction with the matrix is confirmed by the FT-IR analysis
FROM INTERCONNECTORS TO ANODE MATERIALS FOR IT-SOFCs:THE ROLE OF IRON IN La1-xSrxCr1-yFeyO3-δ
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