Engenharia Mecânica
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/23
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4 resultados
Resultados da Pesquisa
- Exergy analysis of the musculoskeletal system efficiency during aerobic and anaerobic activities(2018) Spanghero G.M.; Albuquerque C.; Fernandes T.L.; Hernandez A.J.; Mady C.E.K.© 2018 by the authors.The first and second laws of thermodynamics were applied to the human body in order to evaluate the quality of the energy conversion during muscle activity. Such an implementation represents an important issue in the exergy analysis of the body, because there is a difficulty in the literature in evaluating the performed power in some activities. Hence, to have the performed work as an input in the exergy model, two types of exercises were evaluated: weight lifting and aerobic exercise on a stationary bicycle. To this aim, we performed a study of the aerobic and anaerobic reactions in the muscle cells, aiming at predicting the metabolic efficiency and muscle efficiency during exercises. Physiological data such as oxygen consumption, carbon dioxide production, skin and internal temperatures and performed power were measured. Results indicated that the exergy efficiency was around 4% in the weight lifting, whereas it could reach values as high as 30% for aerobic exercises. It has been shown that the stationary bicycle is a more adequate test for first correlations between exergy and performance indices.
- Clinical application of thermography for energy balance in athletes – State of the art and new paradigms Aplicação clínica da termografia para equilíbrio energético em atletas – Estado da arte e novos paradigmas Aplicación clínica de la termografía para equilibrio energético en atletas – Estado del arte y nuevos paradigmas(2018) Fernandes T.L.; Hernandez A.J.; Albuquerque C.; Mady C.E.K.© 2018, Redprint Editora Ltda. All rights reserved.This article aims to describe the evolution of techniques that have enabled the proper application of the Laws of Thermodynamics for physical activity and athletes. The objective is to propose performance indicators to help add information to the current indices used in medicine and sports, such as the lactate threshold and maximum oxygen consumption. A number of analyses of the results obtained by the group were carried out for this purpose. Moreover, a discussion regarding which techniques would provide a better response to the measurements was analyzed. Some examples are the substitution of the treadmill running test with the stationary bicycle (known performed work), and a literature search in order to measure internal temperature more accurately. Level of Evidence V; Expert opinion.
- Description of an evaluation system for knee kinematics in ligament lesions, by means of optical tracking and 3D tomography Descrição de sistema de avaliação da cinemática do joelho em lesões ligamentares a partir de rastreamento óptico e tomografia 3D(2014) Fernandes T.L.; Ribeiro D.B.; Da Rocha D.C.; Albuquerque C.; Pereira C.A.M.; Pedrinelli A.; Hernandez A.J.© 2014 Sociedade Brasileira de Ortopedia e Traumatologia.Objective: To describe and demonstrate the viability of a method for evaluating knee kinematics, by means of a continuous passive motion (CPM) machine, before and after anterior cruciate ligament (ACL) injury.Methods: This study was conducted on a knee from a cadaver, in a mechanical pivot-shift simulator, with evaluations using optical tracking, and also using computed tomography.Results: This study demonstrated the viability of a protocol for measuring the rotation and translation of the knee, using reproducible and objective tools (error < 0.2 mm). The mechanized provocation system of the pivot-shift test was independent of the examiner and always allowed the same angular velocity and traction of 20 N throughout the movement.Conclusion: The clinical relevance of this method lies in making inferences about the in vivo behavior of a knee with an ACL injury and providing greater methodological quality in future studies for measuring surgical techniques with grafts in relatively close positions.
- Exergy performance of human body under physical activities(2013) Mady C.E.K.; Albuquerque C.; Fernandes T.L.; Hernandez A.J.; Saldiva P.H.N.; Yanagihara J.I.; de Oliveira S.The aim of this work is to apply performance indicators for individuals under physical activity based on the concepts of exergy destroyed and exergy efficiency. The cardiopulmonary exercise test is one of the most used tests to assess the functional capacity of individuals with varying degrees of physical training. To perform the exergy analysis during the test, it is necessary to calculate heat and mass flow rates, associated with radiation, convection, vaporization and respiration, determined from the measurements and some relations found in the literature. The energy balance allowed the determination of the internal temperature over time and the exergy variation of the body along the experiment. Eventually, it was possible to calculate the destroyed exergy and the exergy efficiency from the exergy analysis. The exergy rates and flow rates are dependent of the exercise level and the body metabolism. The results show that the relation between the destroyed exergy and the metabolism is almost constant during the test, furthermore its value has a great dependence of the subject age. From the exergy analysis it was possible to divide the subjects according to their training level, for the same destroyed exergy, subjects with higher lactate threshold can perform more work. © 2013 Elsevier Ltd.