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Vegetable oils are subjected to heat treatments during processing and changes during storage. Thus, it is required, for usage as a food source, the evaluation of their thermo-oxidative stability and physicochemical characteristics. In this context, the objective of this paper was to evaluate the oil of catole coconut (Syagrus cearensis), aiming to characterize its identity and quality, as well as its antioxidant capacity and thermo-oxidative stability. The catole coconut was collected in the city of Lagoa Seca-PB, Brazil, its almonds were dried in a stove and the catole oil was obtained by cold pressing. The results of the physicochemical parameters complied with the current legislation, with average values ​​of 2.48 mg KOH g−1 oil for acid value, 0.14 meq peroxide kg−1 oil for peroxide value and 253 mg KOH g−1 oil for saponification value. Catole oil presented the profile of saturated fatty acids (84.42%), with the predominance of lauric acid (45.06%), besides major phenolic compounds such as salicylic acid [12.324 mg (100 g−1) of oil] and myricetin [1.405 mg (100 g−1) of oil]. The thermogravimetric profile remained stable to decomposition at temperatures up to around 240 °C and oxidative stability withstood at 110 °C for more than 48 h. Therefore, it was possible to identify and characterize this unexplored oilseed species of the Brazilian semiarid, diversifying its use in the food industry. [ABSTRACT FROM AUTHOR]

Banana-crop represents an essential segment in Brazil's socio-economic structure. However, the residues of banana-crop discarded cause problems of contamination in the crop and environment. Waste reuse technologies for the production of new chemical compounds with high conditioning and nutritional potential of soils are emerging as an efficient and economically viable way in terms of production and market value. From this perspective, the banana-crop residues torrefied, containing incorporated fertilizers, appears as an alternative to the reuse of that biomass in the generation of a slow-release biofertilizer. Biochar was produced from banana-crop pseudostem by torrefaction at 240 °C (BF sample). Urea (N), KCl (K), and diammonium phosphate (P) were added to BF, then pelletized to produce the BF-N, BF-K, and BF-P fertilizers. The relative water sorption kinetics by time was evaluated using an exponential method, with a maximum of 10.5% (w/w) sorption for the BF-N sample and a maximum adsorption time (95%) of 22.25h. The swelling of BF in water was evaluated by TMA, with a maximum ε = 22.4%. TG and DTG curves were used to obtain the proximate analysis, the thermal stability of the samples, and the urea content overtime of the BF-N sample in an aqueous medium and soil. FTIR spectra allowed to evaluate the interactions of N, P, and K with BF during the production of BF-N, BF-P, and BF-K. Two models, exponential (EM) and quotient (QM), were proposed and assessed for release kinetic parameters of N, P, and K from BF, BF-N, BF-P, and BF-K fertilizers in water and two kinds of soils under controlled conditions. The kinetics parameters allowed a discussion on the mechanisms of nutrient release in both water and soil, and the adjustment of the kinetic release model showed the potential for application as slow-release fertilizers. [ABSTRACT FROM AUTHOR]

Cellulose nanowhiskers were extracted from the spines of Mandacaru ( Cereus jamacaru DC.), a cactus native to the Caatinga biome of northeastern Brazil, using sulfuric acid hydrolysis preceded by alkaline treatment and bleaching. Results showed that three bleaching steps were required to remove most of the non-cellulosic constituents of the spines that yielded 77.4% cellulose. Nanowhiskers size decreased from about 400 to 260 nm when extraction time varied from 60 to 120 min, this was also evidenced by X-ray diffraction. Alkaline treated and bleached samples had lower thermal stability as compared to untreated spines due to removal of lignin and increased surface area. The amount of time samples were treated with sulfuric acid influenced the thermal stability and consequently the degree of crystallinity of the nanowhiskers. Cellulose nanowhiskers were obtained from Mandacaru spines providing a new renewable source of reinforcement with potential applications in nanocomposites. [ABSTRACT FROM AUTHOR]

The solar cell industry has presented high growth rates and dealt with a large portfolio of suppliers for specific equipments like diffusion furnaces needed to produce the pn junction in the fabrication of silicon devices. The aim of this paper is to present the thermal analysis and the characterization of diffusions carried out in the first diffusion furnace developed and fabricated in Brazil. Longitudinal and radial temperature profiles were measured and analyzed. Results of the characterization defined a processing zone of 200 mm with temperature variation lower than 6°C for the temperatures up to 965°C. In the processing zone, 40 silicon wafers can be processed. Diffusion processes were performed in monocrystalline silicon wafers and n+ regions doped with phosphorus presented standard deviation of sheet resistance slightly higher than that obtained in imported commercial furnaces. Wafer contamination was not observed during diffusion processes and the minority carrier lifetime was improved. [ABSTRACT FROM AUTHOR]