The aim of the present work is to identify the reactions of the dental organs to the different forces that occur during chewing and the transcendence of the union and contact maintained by the dental tissues. The study used a lower first molar biomodel with a real morphology and morphometry and consisting of the three dental tissues (enamel, dentin, and pulp) each with its mechanical properties. In it, two simulations were carried out, as would the process of chewing a food. One of the simulations considers the contact between the enamel and the dentin, and the other does not take it into account. The results obtained differ significantly between the simulations that consider contact and those that do not, establishing the importance of taking this contact into account. In this way, the theories that establish horizontal and lateral occlusion forces are present during the functional chewing process which are viable to be correct. The case studies carried out present not only the reasons for the failure of enamel but also the failure of the restoration materials used. This reflection will allow the development of more adequate materials, mechanical design of prostheses, implants, and treatment.

Abstract. An inverse artificial neural network (ANN) assessment for locating defects in bars with or without notches is presented in the paper. Postulated void defects of 1mm x 1mm were introduced into bars that were impacted with an impulse step load; the resultant elastic waves propagate impinging on the defects. The resultant transient strain field was analyzed using the finite element method. Transient strain data was collected at nodal points or sensors locations on the boundary of the bars and used to train and assess ANNs. The paper demonstrates quantitatively, the effects of features such as the design of ANN, sensing parameters such as number of data collection points, and the effect of geometric features such as notches in the bars.

This paper presents a synthesis of a spherical parallel manipulator for a shoulder of a seven-degrees-of-freedom prosthetic human arm using a multi-objective optimization. Three design objectives are considered, namely the workspace, the dexterity, and the actuators torques. The parallel manipulator is modelled considering 13 design parameters in an optimization procedure. Due to the non-linearity of the design problem, genetic algorithms are implemented. The outcomes show that a suitable performance of the manipulator is achieved using the proposed optimization.

Deployable mechanisms in CubeSat satellites have many problems with the system that provides the anchor position. The main defect of the traditional deployment mechanisms for solar panels in CubeSats is the lack of position system to block the back-driving of the panel when it reaches the final phase of the deployment. This generates spurious oscillations in the panel, affecting the photovoltaic process as well as generating fatigue in the mechanical elements of the mechanism (hinge or pin). In this work, the design, analysis and manufacture of a deployment mechanism for CubeSat solar panels is shown. A finite element method analysis was carried out in a hinge with an integrated blocking system as well as a double torsion spring, which can be used on CubeSats. The outcome shows the layout of the described anchor hinge and the used double-torsion spring, which provides a positive direction torque transfer. Likewise, the performed numerical analyses on the designed system, reduce the weight and optimise the geometry of the mechanism, showing its feasibility as well as the potential applications and further research in the area.

Abstract:The main aim of this study was to characterize cooked bagasse fi bers from Agave angustifolia Haw. The fi bers were characterized using scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray Diffraction and chemical analysis. The tensile strength was also tested using fi bers with a uniform length (30 mm). The fi bers were light brown in color, with a mean diameter and length of 501 μm and 144 mm, respectively. Scanning electron microscopy images revealed elliptically shaped cells with varying lumen size. Holocellulose content was approximately 82.12 %, and total lignin content was approximately 20.69 %. Due to the crystallinity and lignin content, the fi bers proved to be thermo-stable until 220 °C.The mean values of tensile strength, Young's modulus, % strain (ε), and ultimate tensile strength were determined via mechanical tests. The results are comparable to those of other common lignocellulosic fi bers, confi rming their potential use as a reinforcing element in a polymer matrix to form a new biodegradable composite. Keywords: chemical composition, crystallinity, mechanical tests, morphology, thermal analysis Resumen: El objetivo principal de este estudio fue caracterizar las fi bras de bagazo cocido de Agave angustifolia Haw. Las fi bras fueron caracterizadas a través de microscopia electrónica de barrido, calorimetría diferencial de barrido, análisis termogravimétri-cos, difracción de rayos X y análisis químico. También se realizaron pruebas de resistencia a la tracción usando fi bras de longitud constante (30 mm). Las fi bras presentaron un color marrón claro, con diámetro medio de 501 μm y longitud media de 144 mm. Las imágenes del microscopio electrónico de barrido mostraron células de forma elíptica con diferente tamaño de lumen. El contenido de holocelulosa fue alrededor de 82.12 % y el contenido total de lignina de aproximadamente 20.69 %. La fi bra resultó ser térmicamente estable hasta 220 °C debido a la cristalinidad y el contenido de lignina. El esfuerzo de tensión, el módulo de Young, el porcentaje de deformación (ε) y el esfuerzo último de tensión fueron obtenidos de las pruebas mecánicas. Los resultados son comparables a los de otras fi bras lignocelulósicas comunes, lo cual confi rma que estas fi bras tienen potencial como refuerzo en una matriz polimérica para formar un nuevo compuesto biodegradable. Palabras clave: análisis térmico, composición química, cristalinidad, morfología, pruebas mecánicas. ETHNOBOTANY R ecently, research on plant fi bers has been increasing due to the abundance of these materials and their status as renewable resources (Joseph et al., 1999;Ghali et al., 2006;Lucena et al., 2009;Ku et al., 2011;Kestur et al., 2013). Consequently, this focus has led to further research on the specifi c characterization of individual plant fi bers such as bamboo, okra, sisal, and henequen (Mishra et al., 2004; Bé-akou et al., 2008;De Rosa et al., 2010;Liu et al., 2012;Arrakhiz et al., 2013) and studies on composite materials (Mohan...