265 research outputs found

    Experimental Modeling of Cyclists Fatigue and Recovery Dynamics Enabling Optimal Pacing in a Time Trial

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    Improving a cyclist performance during a time-trial effort has been a challenge for sport scientists for several decades. There has been a lot of work on understanding the physiological concepts behind it. The concepts of Critical Power (CP) and Anaerobic Work Capacity (AWC) have been discussed often in recent cycling performance related articles. CP is a power that can be maintained by a cyclist for a long time; meaning pedaling at or below this limit, theoretically, can be continued for infinite amount of time. However, there is a limited source of energy for generating power above CP. This limited energy source is AWC. After burning energy from this tank, a cyclist can recover some by pedaling below CP. In this paper we utilize the concepts of CP and AWC to mathematically model muscle fatigue and recovery of a cyclist. Then, the models are used to formulate an optimal control problem for a time trial effort on a 10.3 km course located in Greenville SC. The course is simulated in a laboratory environment using a CompuTrainer. At the end, the optimal simulation results are compared to the performance of one subject on CompuTrainer.Comment: 6 pages, 8 figure

    Aerospace medicine and biology: A continuing bibliography with indexes, supplement 183

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    This bibliography lists 273 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

    Advances in Mechanical Systems Dynamics 2020

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    The fundamentals of mechanical system dynamics were established before the beginning of the industrial era. The 18th century was a very important time for science and was characterized by the development of classical mechanics. This development progressed in the 19th century, and new, important applications related to industrialization were found and studied. The development of computers in the 20th century revolutionized mechanical system dynamics owing to the development of numerical simulation. We are now in the presence of the fourth industrial revolution. Mechanical systems are increasingly integrated with electrical, fluidic, and electronic systems, and the industrial environment has become characterized by the cyber-physical systems of industry 4.0. Within this framework, the status-of-the-art has become represented by integrated mechanical systems and supported by accurate dynamic models able to predict their dynamic behavior. Therefore, mechanical systems dynamics will play a central role in forthcoming years. This Special Issue aims to disseminate the latest research findings and ideas in the field of mechanical systems dynamics, with particular emphasis on novel trends and applications

    Estudio y desarrollo de un cuadro de descenso

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    L'objectiu del present projecte és estudiar el procés de desenvolupament d'un quadre de bicicleta de descens. Es presenten i s'analitzen al llarg del projecte les diferents etapes. S'avalua el material a utilitzar, una decisió fonamental per al disseny, per la seva influència en la resistència, durabilitat, rigidesa i pes del quadre, i se sospesen diferents alternatives. Es discuteixen aspectes tan fonamentals com la geometria i la cinemàtica de la suspensió, així com el procediment i les eines utilitzades per a la seva definició. També s'aborda el disseny i desenvolupament d'un model virtual i la realització d'assajos segons la norma ISO 4210, relativa als requisits de seguretat per a bicicletes, utilitzant un mètode de simulació per elements finits. S'han emès informes d'assaig sobre el compliment d'aquesta norma, així com una fulla d'assaig en la qual es resumeixen els resultats de la simulació. També s'ha realitzat una anàlisi econòmica dels costos per a dur a terme el projecte, concloent que el cost per a la fabricació d'un prototip real, tal com estava previst inicialment, és prohibitiu. No obstant això, en aquest projecte s'han tingut en compte i recollit tots els passos i consideracions per a la creació d'un prototip. A més, s'analitza la sostenibilitat de les tendències actuals en la indústria de la bicicleta, i es presenten algunes alternatives per a reduir el seu impacte mediambiental.El objetivo del presente proyecto es estudiar el proceso de desarrollo de un cuadro de bicicleta de descenso. Se presentan y se analizan a lo largo del proyecto las diferentes etapas. Se evalúa el material a utilizar, una decisión fundamental para el diseño, por su influencia en la resistencia, durabilidad, rigidez y peso del cuadro, y se sopesan diferentes alternativas. Se discuten aspectos tan fundamentales como la geometría y la cinemática de la suspensión, así como el procedimiento y las herramientas utilizadas para su definición. También se aborda el diseño y desarrollo de un modelo virtual y la realización de ensayos según la norma ISO 4210, relativa a los requisitos de seguridad para bicicletas, utilizando un método de simulación por elementos finitos. Se han emitido informes de ensayo sobre el cumplimiento de esta norma, así como una hoja de ensayo en la que se resumen los resultados de la simulación. También se ha realizado un análisis económico de los costes para llevar a cabo el proyecto, concluyendo que el coste para la fabricación de un prototipo real, tal y como estaba previsto inicialmente, es prohibitivo. No obstante, en este proyecto se han tenido en cuenta y recogido todos los pasos y consideraciones para la creación de un prototipo. Además, se analiza la sostenibilidad de las tendencias actuales en la industria de la bicicleta, y se presentan algunas alternativas para reducir su impacto medioambiental.The objective of the present project is to study the development process of a downhill bicycle frame. The different stages involved are presented and then analysed in the course of the project. Material to use, a fundamental decision for the design because of its influence in resistance, durability, rigidity, and weight of the frame, is evaluated and different alternatives are balanced. Such fundamental aspect as geometry and suspension kinematics are discussed, as well as the procedure and tools used to define them. Design and development of a virtual model and testing as per ISO 4210, regarding safety requirement for bicycles, using a simulation method by finite elements is also covered in the following. Test reports on compliance with this standard have been issued, as well as a test sheet summarising the simulation results. An economic analysis of the costs involved to complete the project has also been conducted, concluding the cost for the manufacturing of a real prototype, as initially planned, is prohibitive. Nevertheless, all steps and considerations for prototyping have been considered and collected in this project. Additionally, sustainability of current tendencies in the bicycle industry is analysed, and some alternatives are presented to reduce its environmental impact

    Aerospace Medicine and Biology: Cumulative index, 1979

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    This publication is a cumulative index to the abstracts contained in the Supplements 190 through 201 of 'Aerospace Medicine and Biology: A Continuing Bibliography.' It includes three indexes-subject, personal author, and corporate source

    Intelligent Transportation Related Complex Systems and Sensors

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    Building around innovative services related to different modes of transport and traffic management, intelligent transport systems (ITS) are being widely adopted worldwide to improve the efficiency and safety of the transportation system. They enable users to be better informed and make safer, more coordinated, and smarter decisions on the use of transport networks. Current ITSs are complex systems, made up of several components/sub-systems characterized by time-dependent interactions among themselves. Some examples of these transportation-related complex systems include: road traffic sensors, autonomous/automated cars, smart cities, smart sensors, virtual sensors, traffic control systems, smart roads, logistics systems, smart mobility systems, and many others that are emerging from niche areas. The efficient operation of these complex systems requires: i) efficient solutions to the issues of sensors/actuators used to capture and control the physical parameters of these systems, as well as the quality of data collected from these systems; ii) tackling complexities using simulations and analytical modelling techniques; and iii) applying optimization techniques to improve the performance of these systems. It includes twenty-four papers, which cover scientific concepts, frameworks, architectures and various other ideas on analytics, trends and applications of transportation-related data

    Performance and Safety Enhancement Strategies in Vehicle Dynamics and Ground Contact

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    Recent trends in vehicle engineering are testament to the great efforts that scientists and industries have made to seek solutions to enhance both the performance and safety of vehicular systems. This Special Issue aims to contribute to the study of modern vehicle dynamics, attracting recent experimental and in-simulation advances that are the basis for current technological growth and future mobility. The area involves research, studies, and projects derived from vehicle dynamics that aim to enhance vehicle performance in terms of handling, comfort, and adherence, and to examine safety optimization in the emerging contexts of smart, connected, and autonomous driving.This Special Issue focuses on new findings in the following topics:(1) Experimental and modelling activities that aim to investigate interaction phenomena from the macroscale, analyzing vehicle data, to the microscale, accounting for local contact mechanics; (2) Control strategies focused on vehicle performance enhancement, in terms of handling/grip, comfort and safety for passengers, motorsports, and future mobility scenarios; (3) Innovative technologies to improve the safety and performance of the vehicle and its subsystems; (4) Identification of vehicle and tire/wheel model parameters and status with innovative methodologies and algorithms; (5) Implementation of real-time software, logics, and models in onboard architectures and driving simulators; (6) Studies and analyses oriented toward the correlation among the factors affecting vehicle performance and safety; (7) Application use cases in road and off-road vehicles, e-bikes, motorcycles, buses, trucks, etc

    Aerospace medicine and biology. A continuing bibliography with indexes, supplement 240, January 1983

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    Reports, articles and other documents, numbering 357, introduced into the NASA scientific and technical information system in December 1982 are given

    Aerospace Medicine and Biology: A cumulative index to a continuing bibliography

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    This publication is a cumulative index to the abstracts contained in Supplements 138 through 149 of AEROSPACE MEDICINE AND BIOLOGY: A CONTINUING BIBLIOGRAPHY. It includes three indexes -- subject, personal author, and corporate source

    Nineteenth Annual Conference on Manual Control

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