Ancient coins: cluster analysis applied to find a correlation between corrosion process and burial soil characteristics

Although it is well known that any material degrades faster when exposed to an aggressive environment as well as that "aggressive" cannot be univocally defined as depending also on the chemical-physical characteristics of material, few researches on the identification of the most significant parameters influencing the corrosion of metallic object are available

Intensity curvature sensor based on photonic crystal fiber with three coupled cores

An intensity curvature sensor using a Photonic Crystal Fiber (PCF) with three coupled cores is proposed. The three cores were aligned and there was an air hole between each two consecutive cores. The fiber had a low air filling fraction, which means that the cores remain coupled in the wavelength region studied. Due to this coupling, interference is obtained in the fiber output even if just a single core is illuminated. A configuration using reflection interrogation, which used a section fiber with 0.13 m as the sensing head, was characterized for curvature sensing. When the fiber is bended along the plane of the cores, one of the lateral cores will be stretched and the other compressed. This changes the coupling coefficient between the three cores, changing the output optical power intensity. The sensitivity of the sensing head was strongly dependent on the direction of bending, having its maximum when the bending direction was along the plane of the cores. A maximum curvature sensitivity of 2.0 dB/m(-1) was demonstrated between 0 m and 2.8 m. (C) 2012 Elsevier B.V. All rights reserved.2852451285131FCT-Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) [SFRH/BD/76991/2011]ANEEL through TBE-Transmissoras Brasileiras de EnergiaERDF-European Regional Development Fund through the COMPETE ProgrammeNational Funds through the FCT-Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) [FCOMP 01-0124-FEDER-022701]FCT-Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) [SFRH/BD/76991/2011]National Funds through the FCT-Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) [FCOMP 01-0124-FEDER-022701

Metais presentes no chorume coletado no aterro sanitário de Ribeirão Preto, São Paulo, Brasil, e sua relevância para saúde pública Metals in landfill leachate in Ribeirão Preto, São Paulo State, Brazil, and its relevance for public health

O presente estudo teve como objetivo a avaliação dos níveis de cádmio, chumbo, cobre, cromo, manganês, mercúrio e zinco, no chorume gerado no aterro sanitário de Ribeirão Preto, São Paulo, Brasil. Amostras do líquido foram coletadas nos tanques de captação do módulo I (funcionou de 1989 até outubro do ano de 2000) e do módulo II (vem funcionando desde novembro do ano de 2000), sendo analisadas por Espectrofotometria de Absorção Atômica no setor de metais do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto. Os resultados foram comparados com os valores máximos permitidos para concentração de metais em efluentes líquidos presentes na Resolução nº. 357/2005 do Conselho Nacional do Meio Ambiente. Foi verificado, também, se existe atenuação na concentração de metais no chorume, considerando a diferença no tempo de vida dos módulos do aterro sanitário em análise. Os resultados deste estudo mostraram que os valores médios de cádmio, cromo, cobre, manganês e mercúrio encontram-se dentro dos limites máximos permitidos, no entanto os valores médios de chumbo e zinco apresentam-se acima dos limites especificados pela referida resolução.<br>This study analyzed the levels of cadmium, lead, copper, chromium, manganese, mercury, and zinc in leachate from the Ribeirão Preto landfill site in São Paulo State, Brazil. Samples were taken from runoff tanks in Module I (operating from 1989 to 2000) and Module II (operating since November 2000). Metal levels were measured by atomic absorption spectrophotometry at the University of São Paulo in Ribeirão Preto (University Hospital). Results were compared to the maximum limits for metal concentration in liquid effluents set by Ruling 357/2005 of the National Environmental Council (CONAMA). The study also investigated whether there was any attenuation in metal concentrations in the leachate, considering differences in the life spans of the various Ribeirão Preto landfill site modules. Metal levels in the samples were within the maximum limits for cadmium, chromium, copper, mercury, and manganese, but lead and zinc were above the limits set by the above-mentioned ruling