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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.

The influence of the addition of bentonite nanoparticles on the tensile and flexural strength of a thermosetting polymer matrix composite material reinforced with hemp fibers was de-terminated. All composites were manufactured with 5% of bentonite in the polymer mass–weight ratios and 10 to 45 wt% of fibers with a step of 5%. For mechanical characterization, tensile and flexural tests were performed: scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses were carried out. The tensile strength of the samples containing bentonite compared to the polymer samples with the fiber addition was affected for all fiber addition percentages, except for 35% while the flexural resistance improved with the addition of bentonite in the percentages of 20, 30, 35, and 45% of fiber addition. With the addition of bentonite, the maximum values of tensile and flexural strength were both obtained for the 35% addition of fibers, with values of 34.28 MPa and 98.04 MPa, respectively. The presence of bentonite favored the rigidity of the material to traction and bending, which was reflected through an increase in the elastic modulus compared to the composite that only had fiber. The maximum values obtained were 9065 MPa in tension and 8453 MPa in flexion for the 40% and 35% of addition of fiber, respectively. Microscopy showed a good distribution of fibers in the matrix, the absence of internal porosities, and a good interaction between matrix and reinforcement.

Resumen 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. Metodo: 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 publicas que fomenten el aprovechamiento de esta herramienta. Abstract Context: Both pioneer countries and those that have recently begun an energy transition towards renewable energy require high levels of flexibility in their electrical systems. This article reviews the Demand Side Management (DSM) application as a tool to provide flexibility, and then, to achieve renewable energy penetration objectives. Method: A systematic mini-review of the literature has been done to review the origin and evolution of the concept of DSM in German and Chilean industry, at the same time, to make a parallel and comparison between them. Results: Both countries have difficulties in taking advantage of the demand management potential in the industry, the lack of promoting policies and the lack of specific regulatory frameworks are some of the causes. Conclusions: It is necessary to speed up attention to the management of demand, it is important that the academy contributes with estimates of potential, it also needs public policies that encourage the use of this tool.

The aim of the present work is to present an alternative way of using SLM in the experimental phase shifting setup to obtain a hologram by using only an illuminating beam. This beam is modified using a Spatial Light Modulator (SLM), where a number of selected SLM pixels generate a plane-illuminating wave with determinate phase, and other pixels generate a plane wave for to be used as reference. The position of these pixels in the SLM is selected symmetrically, and the percentage of them regarding all the SLM pixels is used as a control of the intensity relation between the reference and object beams. An experimental setup of Phase-Shifting Digital Gabor Holography using a reflection SLM, model LR-C-1080 was created. An ad hoc software, that allows modifying the phase of illuminating beam and of course, the object wave phase, the hologram recording and the image reconstruction, was developed in this work. A human hair is used as testing sample, with diameter previously calibrated.

Dentre dos procedimentos geradores de perfil óptico encontra-se a microscopia holográfica digital. Esta ferramenta interferométrica surgiu da ideia inicial proposta por D. Gabor sobre holografia, a qual permite mediante o registro da interferência de campos ópticos coerentes, guardar e extrair informações de imagens. A microscopia holográfica digital permite a análise de objetos com resoluções transversais semelhantes às obtidas por microscopia óptica, e ainda, possui a vantagem pela natureza da holografia de permitir realizar análises através do acesso a valores quantitativos de fase. Apresentam-se neste trabalho os conceitos básicos da holografia digital e da microscopia holográfica digital, com o objetivo, de introduzir o desenvolvimento de uma metodologia para a implementação da microscopia holográfica digital por reflexão para o controle dimensional de objetos e determinação da rugosidade superficial de amostras de aço. Os hologramas são obtidos mediante uma instalação óptica, que consiste em um interferômetro de Michelson por reflexão com o uso de uma lente objetiva de microscópio e uma câmera CCD sem lente. Para a reconstrução das imagens de contraste de fase são utilizadas técnicas numéricas que capacitam à microscopia holográfica digital para a supressão do termo de ordem zero, controle da resolução de pixel, desmodulação da fase óptica, determinação dos mapas de intensidades e fase, filtragem e compensação de aberrações dos hologramas obtidos. As reconstruções numéricas dos feixes objeto e referência são realizadas utilizando o método de dupla propagação. Foi desenvolvido um algoritmo que apresenta a imagem de contraste de fase com base num critério de distância a partir de um único holograma. Desta forma o programa utilizado permite a realização de medições quantitativas das dimensões dos objetos e da rugosidade superficial de amostras de aço, assim como, a representação em 3D da imagem de fase reconstruída com resultados validados através de um perfilômetro óptico 3D sem contacto modelo CCI-MP. Among the procedures generating optical profile is the digital holographic microscopy. This interferometric tool arose from the initial idea proposed by D. Gabor on holography, which allows by recording the interference of coherent optical fields, save and extract information from images. Digital holographic microscopy allows the analysis of objects with transversal resolutions similar to those obtained by optical microscopy, and also has the advantage of the nature of holography to allow to perform analyzes through the access to quantitative phase values. This paper presents the basic concepts of digital holography and digital holographic microscopy, with the objective of introducing the development of a methodology for the implementation of digital holographic microscopy by reflection for the dimensional control of objects and determination of surface roughness of samples of steel. The holograms are obtained by means of an optical installation consisting of a Michelson interferometer by reflection using an objective microscope lens and a lensless CCD camera. For the reconstruction of phase contrast images, numerical techniques are used that enable digital holographic microscopy to suppress the zero-order term, control pixel resolution, optical phase demodulation, determination of intensity and phase maps, filtering and compensation of aberrations of the obtained holograms. Numerical reconstructions of the object and reference beams are performed using the double propagation method. An algorithm has been developed that presents the phase contrast image based on a distance criterion from a single hologram. In this way the program used allows the realization of quantitative measurements of the object dimensions and the surface roughness of steel samples, as well as the 3D representation of the reconstructed phase image with results validated through a 3D contactless optical profilometer model CCI- MP.