Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses

Nanocontact loadings offer the potential to investigate crystal plasticity from surface slip trace emissions and distinct pileup patterns where individual atomic terraces arrange into hillocks and symmetric rosettes. Our MD simulations in FCC Cu and Al nanocontacts show development of specific dislocation interception, cross-slip and twin annihilation mechanisms producing traces along characteristic and directions. Although planar slip is stabilized through subsurface dislocation interactions, highly serrated slip traces always predominate in Al due to the advent of cross-slip of the surfaced population of screw dislocations, leading to intricate hillock morphologies. We show that the distinct wavy hillocks and terraces in BCC Ta and Fe nanocontacts are due to dislocation double-kinking and outward spreading of surfaced screw segments, which originate from dislocation loops induced by twin annihilation and twin-mediated nucleation processes in the subsurface. Increasing temperature favors terrace formation in BCCs whereas the enhancement of surface decorations in FCCs limits hillock definition. It is found that material bulging against the indenter-tip is a distinctive feature in nanocontact plasticity associated with intermittent defect bursts. Bulging is enhanced by recurrent slip traces introduced throughout the contact surface, as in the case of the strongly linear defect networks in FCC Al, and by specific twin arrangements at the vicinity of BCC nanocontacts. Defect patterning also produces surface depressions in the form of vertexes around FCC nanoimprints. While the rosette morphologies are consistent with those assessed experimentally in greater FCC and BCC imprints, local bulging promoted during tip removal becomes more prominent at the nanoscale.Peer ReviewedPostprint (author's final draft

Virtual reality application applied to biomedical models reconstructed from CT scanning

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Robotic arm controlled through vision and biomechanical sensors

The project aims to design the control of a robotic arm capable of following the movements of a real hand. In order to do that, a number of different technologies were implemented: manufacture by adding material (3D printing), Arduino board programming and implementing and programming of vision and biomechanics sensors. The project was developed in 3 stages: First, making a 3D printing of a robotic arm, which has been acquired with CAD software, for subsequent assembly of all parts. Second, programming of an Arduino Uno, capable of operating actuators (servomotors), to perform the movement of the hand built. Finally, developing a programming code capable of receiving, interpreting and manipulating the data obtained by a mocap device (motion capture), communicating with other devices and sending commands to the Arduino Uno controller chip.Postprint (author's final draft

Exploring virtual reality to improve engineering students' spatial abilities pilot study

A Virtual Reality pilot study is conducted to improve the spatial ability of engineering students based on solid geometry scenarios. The investigation focused on the Graphic Expression and Computer-Aided Design (GECAD) course, specifically on the study of the spatial abilities developed and the assessment of the academic results in the solid geometry module. A total of 20 participants completed three activities (6 h) in an immersive virtual learning environment (IVLE), using head-mounted display (HMD) glasses. Modeling exercises of three-dimensional geometric shapes are proposed, based on concepts of solid geometry. The scenarios are built step by step and the students can regulate the progress between stages while observing the geometric components at the scale and in the point of view they wish. Beyond academic results, the assessment of student improvement is based on spatial abilities tests: the Differential Aptitude Test: Spatial Relations Subset DAT-SR, Purdue Spatial Visualisation Test: Rotations PSVT:R and Mental Cutting Test MCT. Those tests are applied for evaluating different skills: mental folding, mental rotation and section by a plane. In summary, a methodology is proposed developing activities in an (IVLE) with 3D modelling software applied in solid geometry, in order to promote the development of spatial ability (SA). Spatial abilities are measured before and after the classroom activities and looking for correlations between the spatial perception tests (DAT:SR, PSVT:R and MCT) and academic results in solid geometry. In addition, we also wish to determine the students' opinion with regard to the proposed activities. The results obtained confirm the interest in using IVLE to develop spatial abilities in engineering students. Substantial increases of 10,9% in DAT:SR, 8,8 % in PSVT:R and 9,5% in MCT between pre- and post-tests were found. Moreover, the students' opinion of IVLE/HMD activities is positive. The methodology can be summarized in the following steps: 1. Students take the DAT:SR , PSVT:R and MCT prior to the activities. They also answer the survey on other variables that can affect SA (1 h). 2. The students individually complete the exercises with the 3D modelling software SolidWorks (10 h). 3. The IVLE activities consist of the guided reading by the professor of the completed exercise. The professor addresses the concepts of solid geometry used in each step. The students have a few minutes to view with HMD the animation showing the construction of the geometric shape, and once the representation is finished, they can move freely throughout the scenario, using the keyboard options (6 h). 4. Students solve the (DAT:SR, PSVT:R and MCT after the IVLE activities. At the end, the groups answer the satisfaction survey (1 h). 5. All the students are evaluated on their knowledge of the solid geometry contents by means of a test and 3D modelling exercises similar to those done in class and those described in the IVRL (1h). 6. Finally, the analysis of the spatial abilities test data, the controlled variables survey, satisfaction surveys and the academic results obtained in the solid geometry module enable us to examine the correlations and the strongest determining factors in order to obtain good academic results and propose IVLE activities to improve the levels of spatial ability obtained on the tests. This paper describes the exploratory methodology used and its results.Postprint (published version

Integration of OpenCV in an Android app to measure antero-posterior knee translation

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An image-analysis-based method to identify the anterior-posterior knee translation and evaluate the need to apply extraarticular tenodesis

Distinció de "Travel Award" al treball presentat al 8th World Congress of Biomechanics, WCB 2018Award-winningPostprint (published version

Análisis de la sensibilidad a las condiciones meteorológicas de los innovadores vuelos parabólicos de la aeronave CAP10B

En estudios previos, utilizamos un software de diseño mecánico CAD Solidworks Motion® para simular el movimiento en el entrenamiento de pilotos acrobáticos. Específicamente, se simuló la maniobra de un vuelo parabólico para un pequeño avión con el objetivo de mejorar diferentes aspectos de la maniobra. El simulador se validó con datos experimentales a partir de test de vuelo y se realizó un periodo inicial de entrenamiento con la ayuda de los datos del simulador. Después de esta formación inicial asistida con la simulación, obtuvimos una mejora significativa en la calidad de la gravedad reducida desde 0,1g0 a 0,05g0. En este artículo, simulamos los efectos de las condiciones atmosféricas en el vuelo parabólico, con el fin de encontrar el efecto de los vientos transversales en la calidad de la micro-gravedad obtenida. Para conseguirlo, se utiliza un sistema de dinámica de fluidos computacional (CFD) SolidWorks Flow Simulation ®

An adaptive methodology for the improvement of knowledge acquisition by a multimedia web tool

Adaptive learning is a method that personalizes the teaching-learning strategies in accordance with the needs and preferences of each student. This article describes the design, the implementation and the tests of a web application developed with adaptive learning in order to improve student knowledge acquisition and to simplify the teacher’s work. The tool uses EventSource technologies combined with heuristic functions to produce a predictive algorithm, which is capable of being adapted to the students in a customized way by presenting the content adjusted according to their cognitive needs. The design is based on the hypothesis that the acquisition of knowledge can be improved by using a computing application which presents a syllabus to be learned in various forms. In this way, the application determines students’ progress within the content of the material, which is classified by branches of knowledge. The tool was applied to one group of students and the data that we obtained was compared with the results of the rest, subject to the usual knowledge transmission system. The results obtained not only improve the academic results, but also enhance the heuristic decision-making about the content to be taught.Peer ReviewedPostprint (published version

Multipurpose virtual reality environment for biomedical and health applications

Virtual reality is a trending, widely accessible, and contemporary technology of increasing utility to biomedical and health applications. However, most implementations of virtual reality environments are tailored to specific applications. We describe the complete development of a novel, open-source virtual reality environment that is suitable for multipurpose biomedical and healthcare applications. This environment can be interfaced with different hardware and data sources, ranging from gyroscopes to fMRI scanners. The developed environment simulates an immersive (first-person perspective) run in the countryside, in a virtual landscape with various salient features. The utility of the developed VR environment has been validated via two test applications: an application in the context of motor rehabilitation following injury of the lower limbs and an application in the context of real-time functional magnetic resonance imaging neurofeedback, to regulate brain function in specific brain regions of interest. Both applications were tested by pilot subjects that unanimously provided very positive feedback, suggesting that appropriately designed VR environments can indeed be robustly and efficiently used for multiple biomedical purposes. We attribute the versatility of our approach on three principles implicit in the design: selectivity, immersiveness, and adaptability. The software, including both applications, is publicly available free of charge, via a GitHub repository, in support of the Open Science Initiative. Although using this software requires specialized hardware and engineering know-how, we anticipate our contribution to catalyze further progress, interdisciplinary collaborations and replicability, with regards to the usage of virtual reality in biomedical and health applications.Peer ReviewedPostprint (author's final draft

Nueva metodología para la evaluación objetiva de la inestabilidad de rodilla. Comparación con los métodos actuales

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