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Abstract

Biodiesel has the advantage of being renewable and clean and for these reasons has been studied recently both academically and in industry. Research in this area is focused on developing new synthetic routes to obtain a purer product or to find new alternative sources of food to replace conventional oils. Papaya biodiesel is obtained from oily residues with a fatty acid composition similar to olive oil. It is generally discarded by the ton, considering that Brazil is the world’s largest producer of papaya with an annual output of 1,811 million tons, productivity of 52 t/hectare and domestic consumption at 86.5%. This study was designed by means of thermal analysis (TG, DSC, P-DSC, and MT-DSC), to verify the possibility of achieving high quality biodiesel, with oxidative stability and flow properties previously indicated by composition analysis of its fatty esters, physical–chemical properties (including oxidative stability) using classical methodology, recommended by ASTM D 6756.

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Summary  

The objective of this study was to use synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF) for the determination of metals and other elements in food available to the population in commercial establishments, in order to evaluate the risks of contamination by these products. The analyzed species were vegetables, leafy vegetables, fruits, cereal and grain. The results indicated that some species were contaminated by Cr, Cu, Zn and Pb with concentrations much higher than the reference values.

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Abstract

Synthesis, characterization, and thermal behavior of transition metal oxamates, M(NH2C2O3)2·nH2O (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II)), as well as the thermal behavior of oxamic acid and its sodium salt (NaNH2C2O3) were investigated employing simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), experimental and theoretical infrared spectroscopy, TG-DSC coupled to FTIR, elemental analysis and complexometry. The results led to information about the composition, dehydration, thermal stability, thermal decomposition, as well as of the gaseous products evolved during the thermal decomposition of these compounds in dynamic air and N2 atmospheres.

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This study uses fishes as indicators of metal contamination in the Piracicaba Basin and also for evaluation of the risks to human health by the ingestion of fish contaminated by metals and other potentially toxic elements. Based on total reflection X-ray fluorescence analysis, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Ba were detected and evaluated in the muscle and viscus (liver, intestine and stomach) of fish collected in the Piracicaba River.

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Summary  

Energy dispersion X-ray fluorescence technique (EDXRF) was employed to study the effects of the fumagina disease through the elementary chemical composition of leaves. The experimental setup consisted of a Mo X-ray tube (Kµ=17.44 keV) with Zr filter and a Si(Li) detector. The measurements were performed with infected and healthy leaves of citric plants. The elements Ti, Mn, Fe, Cu and Zn were quantified. For all the elements of interest the measured detection limit was at the order of mg . g-1.

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Summary  

Total reflection X-ray fluorescence (TXRF) was used to evaluate the availability and contamination of inorganic elements in sediment samples from Atibaia River, located at Piracicaba Basin, near the Campinas region, São Paulo State, Brazil. The total contents (geological matrix) and the concentration of elements weakly linked to the sediment (available fraction) were determined. The availability of these elements was evaluated through the ratios between available fractions and total contents. The results showed that the elements Mn, Ni, Cu and Zn are easily available in the aquatic environment.

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Journal of Thermal Analysis and Calorimetry
Authors: J. C. O. Santos, M. G. O. Santos, J. P. Dantas, Marta M. Conceição, P. F. Athaide-Filho, and A. G. Souza
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Reaction Kinetics, Mechanisms and Catalysis
Authors: Cleanio L. Lima, Hélvio S. A. de Sousa, Santiago J. S. Vasconcelos, Josué M. Filho, Alcemira C. Oliveira, Francisco F. de Sousa, and Alcineia C. Oliveira

Abstract

Sulfated molecular sieves were synthesized and characterized by XRD, FTIR, chemical analyses, acidity measurements and N2 adsorption–desorption isotherms. Sulfatation led to structural changes in the solid framework by increasing the acidity and accessibility of the acid sites. Br⊘nsted and Lewis acid sites of mild to high strength improved the conversion of alcohols, but the selectivity was modest over sulfated FAU type Y, ZSM-5 and γ-Al2O3 solids at temperatures lower than 200 °C. The characteristics of the sulfated AlSBA-15 molecular sieve in terms of acidity, textural properties and accessibility possibly make this solid useful for catalytic reactions involving bulky organic compounds.

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Thermal analysis in sustainable development

Thermoanalytical study of faveleira seeds (Cnidoscolus quercifolius)

Journal of Thermal Analysis and Calorimetry
Authors: J. C. O. Santos, J. P. Dantas, C. A. Medeiros, P. F. Athaíde-Filho, Marta M. Conceiçăo, J. R. Santos Jr., and A. G. Souza
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Journal of Thermal Analysis and Calorimetry
Authors: Marta C. D. Silva, J. R. Botelho, Marta M. Conceiçăo, B. F. Lira, Monyque A. Coutinho, A. F. Dias, A. G. Souza, and P. F. A. Filho
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