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In the search for new solid fuels that can mitigate emissions of greenhouse gases and reduce municipal solid waste, it is proposed to produce a solid fuel from elephant grass charcoal (EGC) and blend it with the following binding recyclable materials, polyethylene terephthalate (PET) and high-density polyethylene (HDPE) with the aim of increasing their mechanical strength. Immediate analysis results indicate that there was an increase in volatile material content from 21.18% to 28.02% and a reduction in fixed carbon from 65.00% to 58.40% with the addition of binding agents. The higher heating value of pure charcoal was 5924.16 kcal/kg and there was no significant alteration by adding HDPE, however, with the addition of PET, there was an average reduction of 4.82%. According to the elemental analysis of charcoal, there were no significant amounts of sulphur, but silicon and potassium oxides were predominantly composed followed by aluminium, titanium, magnesium and iron according to the analysis of ashes. The addition of thermoplastic binders allowed producing pellets and it was found that those produced by using HDPE are stronger than those produced with PET.

The possibility of recycling and the favorable mechanical properties of the products have encouraged the study and production of thermoplastic composites from natural fibrous waste. Açaí (cabbage palm) fiber, which is removed from the seed, has been slightly investigated, as compared to what is already known about the fruit pulp. In this study, the influence of açaí fiber as an element of reinforcement in recycled everyday usage thermoplastics using simple, low cost methodology was evaluated. Recycled matrixes of high impact polystyrene and polypropylene were molded by hot compression from which the fiber composites were obtained. The FTIR technique showed that the process was efficient in preventing degradation of the açaí fibers. The influence of the fiber on the mechanical behavior of the recycled matrixes was investigated by microscopic images of compression and impact tests. The results showed better impact performance for the fiber combined with the polymeric matrixes.

This paper discusses the application of ultrasound waves on a Brazilian hardwood, Goupia glabra, to evaluate the sensitivity of the ultrasonic technique to the moisture content in wood. The velocity of ultrasonic wave is sensitive to the material's quality-determining factors; hence, this technique is an important industrial tool to improve the quality control of processes. The nature of the response of velocity of sound to changes in moisture content led us to conclude that moisture gradients during drying exert a dominating effect. The ultrasonic velocity was measured both parallel and perpendicular to the fibers of Goupia glabra during drying from green to 6% moisture content. The results of this study showed that velocity of ultrasonic waves is sensitive to changes in moisture content of lumber during drying. The velocity under dry conditions was always higher than the velocity under more humid conditions, in both directions of propagation.