Metal-free activated biochar as an oxygen reduction reaction catalyst in single chamber microbial fuel cells

Metal-free catalysts are promising candidates for Bio-electrochemical Systems (BESs) due to their high surface area, chemical stability, good electrical conductivity, and enhanced mass-transport capabilities. In this study, biochars derived from olive mill waste (OMW) with and without supercritical CO2 pretreatment, and salted pistachio nut shells, were produced via pyrolysis and/or chemical and physical activation. The catalytic activity towards oxygen reduction reactions (ORR) of the biochars was investigated by cyclic and linear sweep voltammetry in neutral media. The electrochemical characterization of the samples revealed that olive mill waste biochar showed the highest catalytic activity toward ORR, in terms of reaction rate (Epr V vs. RHE = 0.537 \ub1 0.00), density of active sites, and number of electrons exchanged (ne- E@ 120.6 V vs. RHE = 3.9 \ub1 0.2). These biochars were used as catalysts in air cathode microbial fuel cells. The power density obtained by MFCs equipped with an OMW cathode achieved a maximum power density of 271 \ub1 34 mWm 122 (Rext = 250 \u3a9). This value was approximately 15 times higher than the power density obtained by a commercial carbon black used as control

Non-places are inhabited. Transnational Comparative Research Report on youth violence and social exlusions on the railway and bus stations of Pescara (Italy), Barcelona (Spain) and Porto (Portugal)

This report was produced within the project “Violence in Transit” (JUST/2010/DAP3/AG/1231) financed by the European Commission in the frame of the Daphne III Funding Programme of the DG Justice. The project, coordinated by On the Road ONLUS Association (Italy), was carried out in collaboration with the partners: EAPN Portugal - Rede Europeia Anti Pobreza (Portugal), APIP-ACAM Foundation (Spain), Europe Consulting Onlus (Italy) and the associates: Ferrovie dello Stato Italiane (Italy), OSCE-Organization for Security and Co-operation in Europe - The Office of the Special Representative and Co-ordinator for Combating Trafficking in Human Being (Austria).info:eu-repo/semantics/publishedVersio

Sex ratios of loggerhead sea turtles Caretta caretta during the juvenile pelagic stage

Sex ratios are a fundamental trait for species reproduction. In species with temperature-dependent sex determination (TSD), sex ratios are not necessarily even, which has important demographic consequences. We examined the sex ratio of juvenile pelagic stage loggerhead turtles Caretta caretta offshore Madeira Island, North Eastern Atlantic, using laparoscopy and histology. The overall sex ratio was 2:1 (F:M), significantly different from an even sex ratio. Although there was no apparent temporal variation, sex ratios among size classes were significantly different. The sex ratio of juveniles was compared with known sex ratios for the putative source rookery and found to be similar to the subadults’ sex ratio, but significantly less female-biased than the hatchlings sex ratio. This suggests overestimation of hatchlings sex ratios and/or, less likely, differential mortality of females during the first months of life. Alternatively, the Madeira Island aggregation may be recruiting males from other geographical sources such as the Mediterranean and the Cape Verde