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The spent bleaching clays (SBC) of vegetable oil refining plants have residual vegetable oil contents ranging from 17 to 40 wt%. The common worldwide practice of landfilling such spent clays imposes inevitable environmental hazards. The extraction of oil from a spent clay will not only alleviate this problem, but can also provide an oil source for processes, such as transesterification for the production of alcohol-esters. In-situ transesterification of the residual oil within SBC is an even more attractive idea, as it can eliminate the extraction step from the process. In this study, in-situ transesterification on the spent bleaching clay of a local vegetable oil plant was investigated experimentally. Furthermore, optimum operating conditions were determined for a number of parameters influencing the conversions, including reaction temperature, ethanol-to-SBC ratio, alkali catalyst type, and catalyst-to-SBC mass ratio. The experiments were designed by the response surface method based on the central composite approach (RSM-CCD model). The results were analyzed using the analysis of variance method (ANOVA) to investigate the effect of the parameters on the efficiencies of the biodiesel produced and the oil removed from the initial SBC. Within the ranges investigated, the maximum conversion to ethyl-ester was 72.90% at the optimum conditions of a reaction temperature of 73.2 °C, reaction time of 4.5 h, ethanol/SBC ratio of 4.2 ml/g, while using NaOH alkali catalyst with a catalyst-to-SBC mass ratio of 4.33%.

The present work has been aimed to study the microstructures, functional properties and the influence of different thermomechanical training methods on the two-way shape memory effect in NiTi-based melt-spun ribbons. In order to get small-dimensioned shape memory alloys (SMAs) with good functional and mechanical properties, a rapid solidification technique was employed. Their fracture and elasticity characteristics have been determined, as well as shape memory properties by thermomechanical cycling. The ribbons were trained under tensile and bending deformation by thermal cycling through the phase transformation temperature range. The results displayed that all different training methods were effective in developing a two-way shape memory effect (TWSME). The influence of copper (5–25 at.% Cu) and tungsten (2 at.% W) on the microstructure, and the functional and mechanical behavior of NiTi thin ribbons was also investigated. All samples show a shape memory effect immediately after processing without further heat treatment. The melt-spun ribbons were trained under constant strain (bending and tensile deformation) by thermal cycling through the phase transformation temperature range. The addition of copper was effective to narrow the transformation hysteresis. The W addition has improved the TWSME stability of the NiTi alloys and mechanical properties. Results about microstructures, functional and mechanical properties will be presented.