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.
According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.
pela pronta disposição, apoio e infra estrutura disponibilizada na colaboração e intensa ajuda na realização de análises de metais. Ao Engenheiro Carlos Roberto Ferreira, Engenheiro responsável pela operação da ETE-Ribeirão Preto, pela confiança e apoio para o desenvolvimento deste estudo. E a engenheira Química Karina Carregari pelo apoio na coleta das amostras. A grande amiga Meire Nikaido por perder suas férias e estar junto comigo colaborando todos os dias fazendo a coleta. E minha grande amiga, a minha orientadora, que me ajudou muito nos dias em que não pude ir.
Objective: To evaluate pediatric radiation exposure in procedures of interventional radiology in two hospitals in the Bahia state, aiming at contributing to delineate the scenario at the state and national levels. The knowledge of exposure levels will allow an evaluation of the necessity of doses optimization, considering that peculiarities of radiology and pediatrics become even more significant in interventional radiology procedures which involve exposure to higher radiation doses. Materials and Methods: A total of 32 procedures were evaluated in four rooms of the two main hospitals performing pediatric interventional radiology procedures in the Bahia state. Air kerma rate and kerma-area product were evaluated in 27 interventional cardiac and 5 interventional brain procedures. Results: Maximum values for air kerma rate and kerma-area product and air kerma obtained in cardiac procedures were, respectively, 129.9 Gy.cm 2 and 947.0 mGy; and, for brain procedures were 83.3 Gy.cm 2 and 961.0 mGy. Conclusion: The present study results showed exposure values up to 14 times higher than those found in other foreign studies, and approximating those found for procedures in adults. Such results demonstrate excessive exposure to radiation, indicating the need for constant procedures optimization and evaluation of exposure rates.Objetivo: Avaliar as exposições pediátricas de radiologia intervencionista em dois hospitais do Estado da Bahia, visando contribuir para a construção de um cenário estadual e nacional, possibilitando o conhecimento das exposições e da necessidade de sua otimização, visto que as peculiaridades que envolvem a radiologia e a pediatria se potencializam quando se trata de procedimentos de radiologia intervencionista, em razão das doses elevadas de radiação. Materiais e Métodos: Foram avaliados 32 procedimentos em quatro salas nos dois principais hospitais que realizam procedimentos de radiologia intervencionista pediátrica na Bahia. Foram avaliados os valores de kerma no ar incidente e o produto kerma-área no ar de 27 procedimentos cardiológicos e 5 procedimentos cerebrais. Resultados: Os valores máximos de produto kerma-área e kerma obtidos para procedimentos cardiológicos foram, respectivamente, 129,9 Gy.cm 2 e 947,0 mGy, e para procedimentos cerebrais, 83,3 Gy.cm 2 e 961,0 mGy. Conclusão: Os resultados deste estudo mostraram valores de exposições superiores em até 14 vezes os obtidos em estudos realizados em outros países, chegando próximos de resultados obtidos para procedimentos em adultos. Isto revela quão elevadas podem ser as exposições pediátricas, indicando a necessidade de constante otimização dos procedimentos e avaliação das exposições. Unitermos: Proteção radiológica; Radiologia intervencionista; Pediatria.
AbstractResumo * Study developed in the Postgraduate Programme in Physics
Solar energy presents the greatest potential by which to produce heat energy with reduced carbon emissions for power generation. To increase its harvesting and conversion, it is necessary to understand fundamental concepts and develop new materials. Although many processes can obtain selective absorbing surfaces (SAS) for application in solar energy exploitation, including electroplating methods, those processes have not sufficiently investigated the substrate’s treatment impact. The present work investigates 304 stainless steel (SS304) substrates treatment influence on the film’s (coatings) optical properties of SAS based on CrO3 electroplating. For this purpose, three main steps featured in the methodology: substrates treatment, coatings deposition, and physical-chemical characterization. The former was performed by detergent cleaning (DC), acid treatment (AT), and electropolishing (EP). Then, coatings were electroplated towards chromium deposition on the substrates with different deposition times. Finally, films were characterized by Profilometry, UV-Vis-NIR, and IR regions Spectroscopy and Scanning Electron Microscopy (SEM). The results indicated that, in terms of surface treatments on the substrate, the electropolished (EP) substrates presented average roughness values of 35 nm, reflectivity of 5.09%, and clear morphological difference (SEM) when compared to other treatments in this study (DC and AT). A SAS was successfully obtained, and the electropolished substrates (EP) presented coatings with better optical performance than other samples (DC and AT), with absorptivity values around 98% and emissivity of approximately 7%. A relationship between substrate treatment, its roughness, and the impacts on the optical selectivity of SASs was observed. Therefore, electropolishing is presented as a promising treatment for the SASs substrates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.