Composites with natural lignocellulosic fillers are being cited as a viable and sustainable alternative to conventional materials, as they combine lower costs with lower weight. In many tropical countries, such as Brazil, there is a considerable amount of lignocellulosic waste that is improperly discarded, which causes pollution of the environment. The Amazon region has huge deposits of clay silicate materials in the Negro River basin, such as kaolin, which can be used as fillers in polymeric composite materials. This work investigates a new composite material (ETK) made of epoxy resin (ER), powdered tucumã endocarp (PTE), and kaolin (K), without coupling agents, with the aim of producing a composite with lower environmental impact. The ETK samples, totaling 25 different compositions, were prepared by cold molding. Characterizations of the samples were performed using a scanning electron microscope (SEM) and a Fourier-transform infrared spectrometer (FTIR). In addition, the mechanical properties were determined via tensile, compressive, three-point flexural and impact tests. The FTIR and SEM results showed an interaction between ER, PTE, and K, and the incorporation of PTE and K reduced the mechanical properties of the ETK samples. Nonetheless, these composites can be considered potential materials to be used for sustainable engineering applications in which high mechanical strength is not a main requirement of the material.
A characterization of composite materials of a polyester matrix reinforced with natural fibers of Cuban henequen and organophilized Cuban bentonite was carried out, the experimental results of which are used to formulate, implement, and validate a scalar damage model. The fibers were added on a weight basis of 15, 20, and 25% as a reinforcing material, and organophilized Cuban bentonite, in amounts of 3, 5, and 7% by weight, was added. Samples containing only polymer and fibers showed the best mechanical performance for 25% of fiber, with increases of 51% in the tensile strength and 169% on the impact resistance. Samples containing polymer and clay showed the best results for 5% of bentonite, with increases of 89% in the tensile strength and 83% on the impact resistance, and samples containing 25% fiber and 5% clay were also prepared and achieved a 98% increase in the tensile strength and 219% in the impact strength. The scalar damage model deals with an internal variable, which corresponds to the damage variable, together with a failure surface that allows identifying the mechanical state of the material dependent on the mechanical stress, obtaining an adequate correlation with the results of the experimental tests.
Contexto: Tanto países pioneros como aquellos que recientemente han comenzado una transición energética hacia las energías renovables requieren altos niveles de flexibilidad en sus sistemas eléctricos. Este artículo revisa la aplicación de la gestión de la demanda (DSM, por sus siglas en inglés) como herramienta para proveer flexibilidad y lograr objetivos de penetración de fuentes renovables de energía.
Método: Se ha hecho una revisión sistemática de la literatura para revisar el origen y evolución del concepto de DSM en la industria alemana y chilena, realizando al mismo tiempo un paralelo y comparación entre ambas experiencias.
Resultados: Ambos países registran dificultades a la hora de aprovechar el potencial de gestión de la demanda en la industria, la falta de políticas promotoras y la carencia de marcos regulatorios específicos son algunas de las causas.
Conclusiones: Se requiere agilizar la atención a la gestión de la demanda; además, es importante que la academia contribuya con estimaciones de potencial en tanto se precisan políticas públicas que fomenten el aprovechamiento de esta herramienta.
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