Appraisal of open software for finite element simulation of 2D metal sheet laser cut.

FEA simulation of thermal metal cutting is central to interactive design and manufacturing. It is therefore relevant to assess the applicability of FEA open software to simulate 2D heat transfer in metal sheet laser cuts. Application of open source code (e.g. FreeFem++, FEniCS, MOOSE) makes possible additional scenarios (e.g. parallel, CUDA, etc.), with lower costs. However, a precise assessment is required on the scenarios in which open software can be a sound alternative to a commercial one. This article contributes in this regard, by presenting a comparison of the aforementioned freeware FEM software for the simulation of heat transfer in thin (i.e. 2D) sheets, subject to a gliding laser point source. We use the commercial ABAQUS software as the reference to compare such open software. A convective linear thin sheet heat transfer model, with and without material removal is used. This article does not intend a full design of computer experiments. Our partial assessment shows that the thin sheet approximation turns to be adequate in terms of the relative error for linear alumina sheets. Under mesh resolutions better than 10e−5 m , the open and reference software temperature differ in at most 1 % of the temperature prediction. Ongoing work includes adaptive re-meshing, nonlinearities, sheet stress analysis and Mach (also called ‘relativistic’) effects.

Graph-based structural analysis of planar mechanisms.

Kinematic structure of planar mechanisms addresses the study of attributes determined exclusively by the joining pattern among the links forming a mechanism. The system group classification is central to the kinematic structure and consists of determining a sequence of kinematically and statically independent-simple chains which represent a modular basis for the kinematics and force analysis of the mechanism. This article presents a novel graph-based algorithm for structural analysis of planar mechanisms with closed-loop kinematic structure which determines a sequence of modules (Assur groups) representing the topology of the mechanism. The computational complexity analysis and proof of correctness of the implemented algorithm are provided. A case study is presented to illustrate the results of the devised method.

Upper Limb Posture Estimation in Robotic and Virtual Reality-based Rehabilitation.

New motor rehabilitation therapies include virtual reality (VR) and robotic technologies. In limb rehabilitation, limb posture is required to (1) provide a limb realistic representation in VR games and (2) assess the patient improvement. When exoskeleton devices are used in the therapy, the measurements of their joint angles cannot be directly used to represent the posture of the patient limb, since the human and exoskeleton kinematic models differ. In response to this shortcoming, we propose a method to estimate the posture of the human limb attached to the exoskeleton. We use the exoskeleton joint angles measurements and the constraints of the exoskeleton on the limb to estimate the human limb joints angles. This paper presents (a) the mathematical formulation and solution to the problem, (b) the implementation of the proposed solution on a commercial exoskeleton system for the upper limb rehabilitation, (c) its integration into a rehabilitation VR game platform, and (d) the quantitative assessment of the method during elbow and wrist analytic training. Results show that this method properly estimates the limb posture to (i) animate avatars that represent the patient in VR games and (ii) obtain kinematic data for the patient assessment during elbow and wrist analytic rehabilitation.

La cirugía bariátrica: una vivencia espinosa pero satisfactoria

La obesidad constituye un problema de salud pública mundial. Quienes la padecen presentan mayores problemas de salud, por lo que muchos optan por la cirugía bariátrica como única solución. Objetivo: Describir el significado de la experiencia de personas que se les hizo cirugía bariátrica en municipios del área Metropolitana del Valle de Aburrá, Medellín Colombia entre 2008 y 2012. Método: Investigación cualitativa, aprobada por el Comité de Ética de la Facultad de Enfermería de la Universidad de Antioquia-Colombia, 23 participantes mayores de 18 años; el análisis se hizo con base en la teoría fundamentada. Resultados: Para los participantes, el posoperatorio de cirugía bariátrica fue un proceso espinoso, complejo; alimentarse fue una tortura; los cambios físicos, emocionales y en su imagen corporal les produjeron ansiedad y dificultaron la aceptación de otros. Pero también adquirieron hábitos y comportamientos que mejoraron su calidad de vida al sentirse felices y satisfechos con sus cuerpos. Conclusiones: La persona sometida a cirugía bariátrica se enfrenta a diversos problemas que requieren apoyo y acompañamiento del equipo de salud para superarlos; también adquiere conductas y comportamientos que aumentan la autoestima, la confianza en sí misma y la calidad de vida.

Buenas noches... ¡soy un milagro!, después de la tempestad : la última copa 7

Fondo Margaritainés Restrepo

Los alcohólicos recuperados lo saben, los mejores días están por llegar, gracias, no bebo, contra el zarpazo de la leona : la última copa 8

Fondo Margaritainés Restrepo

Dicen los médicos especialistas : no es asunto de plata, sino de honorarios justos, el fondo del asunto

Fondo Margaritainés Restrepo