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Anatase TiO2 and TiO2 films containing Pt nanoparticles were prepared by sol–gel dip coating method and characterized by X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Further, optoelectronic properties were investigated, showing that for anatase TiO2 films containing Pt nanoparticles there were not changes in the band-gap value in respect to TiO2 films here obtained. However, an increase in the photoresponse and a decrease in resistivity with increase in the Pt % weight (% w) in sol were found. Keywords: TiO2 films, Solar energy, Nanoparticles

The production of biofuels (biogas, ethanol, methanol, biodiesel, and solid fuels, etc.), beginning with cocoa pod husk (CPH), is a way for obtaining a final product from the use of the principal waste product of the cocoa industry. However, there are limitations to the bioconversion of the material due to its structural components (cellulose, hemicellulose, and lignin). Currently, CPH pretreatment methods are considered a good approach towards the improvement of both the degradation process and the production of biogas or ethanol. The present document aims to set out the different methods for pretreating lignocellulosic material, which are: physical (grinding and extrusion, among others); chemical (acids and alkaline); thermochemical (pyrolysis); ionic liquid (salts); and biological (microorganism) to improve biofuel production. The use of CPH as a substrate in bioconversion processes is a viable and promising option, despite the limitations of each pretreatment method.

In this paper, the gradient temperature and the thermomechanical stresses of a photovoltaic panel has been studied with and without heatsink. For this purpose, a three-dimensional analysis was carried out. Accordingly, a heat transfer analysis was developed. The numerical results show a cooling close to 26.7% with the proposed triangle fins compared with the rectangular fins studied before by another author, and the temperature distribution was determined. With this information, the stress analysis was carried out in order to find the effect on the panel due to the thermomechanical stresses. The aluminium frame was restricted to move freely. The resulting stresses field established the magnitude of the alternative stresses, resulting in a 6.7% drop compared with a reference panel. The guidelines of IEC 61215 have to be take into account. Due to the results obtained, the use of this kind of system in desert conditions is desirable because of its high operational temperature and due to the increase in heat transfer by the fins.