Andrea Cavicchioli

O uso de radiação ultravioleta para o pré-tratamento de amostras em análise inorgânica

The basic principles of UV irradiation as sample pre-treatment step and its potential for inorganic analysis are illustrated and discussed through significant examples from the literature. Not only does this overview cover the classical applications of this technique in the decomposition of organic matter in electroanalysis, but it also presents recent trends, including the increasing interest in employing UV irradiation in flow analytical systems, successful attempts to enhance its effectiveness and the coupling with chromatographic and spectroscopic methodologies. Furthermore, a number of relevant cases of UV-driven derivatization reactions involving photo-sensitive inorganic species are presented, showing some convenient options to perform fast and reliable determination of inorganic and organic analytes.

Effect of scavengers on the photocatalytic digestion of organic matter in water samples assisted by TiO2 in suspension for the voltammetric determination of heavy metals

The influence of electron and hole scavengers in the photocatalytic digestion of organic matter in the presence of suspended particles of TiO2 was investigated. The process, aiming at the electrochemical determination of traces of heavy metals in water samples, was followed through the recovery of the voltammetric wave of Cd(II) in the presence of EDTA, chosen as model ligand that mimics the complexing effect of natural dissolved organic matter. The accelerating power of O2, acting as electron scavenger, was confirmed. In the absence of O2, a similar function is played by nitrate ions but not, as it seems, by the analyte, Cd(II). On the other hand, CH3OH exhibits an antagonist effect as hole scavenger. This observation may explain why the acetate (from the pH buffer), used to control the medium acidity, leads to a certain reduction in the photocatalytic yield.

Câmaras climáticas para o envelhecimento acelerado: ação de microambientes sobre bens culturais

Environmental chambers were designed for the accelerated ageing of materials used in artistic artifacts to study the synergistic action of temperature, humidity, UV and visible radiation and gaseous pollutants. Two inox-steel/PTFE compartments are kept under controlled temperature and relative humidity, whose values are transmitted to a PC, which stores, plots in real time and continuously feedback heating and humidifying devices through logical signals. A borosilicate, or quartz, window allows the irradiation inside the chamber from an external source. A flow of purified air purges the chamber and conveys selected pollutants from an external source. Each independent compartment works under either stationary or cyclic conditions.

Particulate matter in the indoor environment of museums in the megacity of São Paulo

Atmospheric pollutants can have serious impacts on the preservation of Sao Paulos tangible cultural heritage. The purpose of this paper is to report the results of a monitoring campaign focussed on particulate matter (PM) that was conducted in three of the most important museums of the Sao Paulo megacity (Brazil): the Museu de Arqueologia e Etnologia (MAE-USP), the Museu Paulista (MP-USP), and the Pinacoteca do Estado de Sao Paulo (PE). These museums exhibit indoor PM and black carbon (BC) concentrations consistent with their urban locations and their specific methods for managing the indoor environment.

CONTROVÉRSIAS AMBIENTAIS FRENTE À COMPLEXIDADE DAS MUDANÇAS CLIMÁTICAS

O artigo discute as transformacoes da tematica ambiental entre 1992 (Conferencia do Rio) e 2012 (Conferencia Rio + 20) destacando as controversias, impasses e desafios dessa problematica enfocando as mudancas climaticas, fundamentados em abordagem comparativa e na nocao de complexidade geopolitica, a qual norteia as analises e a compreensao dos processos. Assim, contextualiza-se essa questao no cenario internacional, enfatizando a posicao e tendencias dos distintos paises, com relacao as mudancas tecnico- -politicas da mitigacao para a adaptacao. Nesse debate assumimos que se tornou inevitavel a adocao de medidas de adaptacao e de gestao ambiental, no âmbito local, para enfrentar uma situacao dominada pelo impasse politico e diplomatico.

Avaliação e perspectivas da abordagem à conservação do patrimônio organístico no Brasil

Orgaos de tubos sao construidos no Brasil, ou importados do exterior, desde as primeiras decadas do periodo colonial. Estes instrumentos, apesar de constituirem um conjunto relativamente exiguo, representam um testemunho historico e musical de valor inestimavel. No entanto, de um modo geral, encontram-se em condicoes precarias de funcionamento e, em parte, mais ou menos descaracterizados profundamente, quanto a sua estrutura e configuracao original, as vezes em estado de abandono e, por incrivel que pareca, ainda sujeitos ao risco de intervencoes arbitrarias e desprovidas de bases tecnicas e de preocupacao historica e musicologica. Neste artigo, busca-se percorrer o caminho que levou a atual situacao e discutem-se os principios e os criterios de processos de recuperacao, manutencao e conservacao preventiva desse patrimonio, partindo dos pressupostos do respeito a sua originalidade e do direito a restauros segundo os rigorosos cânones ja definidos para objetos com plena condicao de bem cultural, cujo reconhecimento para os orgaos de qualquer epoca deve ser urgentemente garantido.