1,721,136 research outputs found
Individual optimal frequency in whole-body vibration. Effect of protocol, joint angle, and fatiguing exercise
No full textCarlucci, F, Felici, F, Piccinini, A, Haxhi, J, and Sacchetti, M. Individual optimal frequency in whole-body vibration: effect of protocol, joint angle, and fatiguing exercise. J Strength Cond Res 30(12): 3503-3511, 2016-Recent studies have shown the importance of individualizing the vibration intervention to produce greater effects on the neuromuscular system in less time. The purpose of this study was to assess the individual optimal vibration frequency (OVF) corresponding to the highest muscle activation (RMSmax) during vibration at different frequencies, comparing different protocols. Twenty-nine university students underwent 3 continuous (C) and 2 random (R) different vibrating protocols, maintaining a squat position on a vibration platform. The C protocol lasted 50 seconds and involved the succession of ascending frequencies from 20 to 55 Hz, every 5 seconds. The same protocol was performed twice, having the knee angle at 120° (C) and 90° (C90), to assess the effect of joint angle and after a fatiguing squatting exercise (CF) to evaluate the influence of fatigue on OVF assessment. In the random protocols, vibration time was 20 seconds with a 2-minute (R2) and a 4-minute (R4) pauses between tested frequencies. Muscle activation and OVF values did not differ significantly in the C, R2, and R4 protocols. RMSmax was higher in C90 (p < 0.001) and in CF (p = 0.04) compared with the C protocol. Joint angle and fatiguing exercise had no effect on OVF. In conclusion, the shorter C protocol produced similar myoelectrical activity in the R2 and the R4 protocols, and therefore, it could be equally valid in identifying the OVF with considerable time efficiency. Knee joint angle and fatiguing exercise had an effect on surface electromyography response during vibration but did not affect OVF identification significantly
Acoustic design and optimization of an organic architecture, a cross disciplinary design of an open-space airport case study
Full text linkArchitectural innovation, both at morphological and technological scale, have increased the importance of new methodologies and tools for the building performance analysis. New organic shapes have decreased the reliability of traditional specialistic knowledge, highlighting the importance of new methodologies to manage complex models and analyse the indoor comfort. The aim of this paper is to present a case study of the acoustic design of an organic open-space airport, realized integrating architectural and acoustic concepts in the design workflow. The building, characterized by a curvilinear plan, a wavy suspended ceiling, and a tilted façade, behave as a single tall, large volume containing different small low-height closed service boxes. This architectural approach leads to a mixture of functions in the same large volume with a resulting complex problem of acoustic optimization. To that end, different studies have been conducted from the protection from external noise to the optimization of the reverberation time, and to the design of the speakers. Considering the geometric complexity, different tools and a particular methodology have been used to properly model the building and to optimize the use and the placement of acoustic absorbing materials
L'osteosintesi con chiodo deformabile secondo Galluccio. Prime esperienze nei piccoli animali
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Hybrid electric vehicles: Some theoretical considerations on consumption behaviour
No full textSolving the problem of the lack of environmental sustainability in transport activities requires the involvement of new technologies, particularly in populated cities where mobility activities play a major role in generating externalities. The move from cars powered by conventional internal combustion engines to cars powered by alternative energies can make an important contribution to reducing emissions and achieving a more sustainable transport system. Unfortunately, green car market development still remains uncertain because of the higher production costs of batteries and engines. In this context, surprisingly little attention has been devoted to analysing the economic factors affecting consumers' behaviour in the choice of hybrid electric vehicles. To fill this gap, the diffusion process of hybrid technology as well as intrinsic and extrinsic motivations and the crowding-out effect on consumers' purchasing decisions are taken under consideration. Finally, some policy recommendations are provided
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