Renato P Freitas

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To the casual observer, it would seem that the United States' suicide rate has been remarkably steady in recent years. However, this stability may be more apparent than real. While it is true that the total suicide rate has varied little, this composite figure masks a dramatic shift in the risk of suicide by age. In recent years there has been a reduction(More)
In this study, twenty samples of clay smoking pipes excavated in an 18km(2) area between the Macacu and Caceribu rivers, in the municipality of Itaboraí, Rio de Janeiro, Brazil were analyzed by FT-IR technique. The samples, excavated in different archeological sites of the region, are dated between the seventeenth and the nineteenth centuries and are part(More)
In this study, samples were taken from the sculpture of Our Lady of Sorrows and analyzed by Raman spectroscopy and FT-IR. This sculpture has been dated to the early eighteenth century. Samples were also examined using optical microscopy and Energy Dispersive Spectroscopy (EDS). Based on chemical analysis, the pigments vermilion [HgS], massicot [PbO] and(More)
Saturating wood particles with HCl gas under pressure was found to be an effective pretreatment prior to subjecting wood to dilute acid hydrolysis. Pretreament is necessary to release sugars from wood because of the tight lattice structure of cellulose. The HCl gas makes the cellulose more susceptible to subsequent acid hydrolysis and the glucose yield is(More)
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