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The increase of surface electromyography (sEMG) root-mean-square (RMS) is very frequently used to determine fatigue. However, as RMS is also influenced by muscle force,its effective usage as indicator of fatigue is mainly limited to isometric, constant force tasks.This research develops a simple methodto preclude the effect of muscle force, hereby estimates the EMG amplitude response exclusively to fatigue with RMS. Experiment was carried out on the biceps brachiis of 15 subjects (7males, 8 females) during sustained static maximum voluntary contractions (sMVC).Result shows that the sEMG RMS response to fatigue increasesto 21.27% while muscle force decreasing to 50%MVC, which implies that more and more extra effort is needed as muscle fatigue intensifies. It would be promising to use the RMS response exclusively to fatigue as an indicator of muscle fatigue.

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Biomechanical motion simulation and dynamic analysis of human joint moments will provide insights into Musculoskeletal Disorders. As one of the mainstream simulation tools, OpenSim uses proportional scaling to specify model segment masses to the simulated subject, which may bring about errors. This study aims at estimating the errors caused by the specifying method used in OpenSim as well as the influence of these errors on dynamic analysis. A 3D scan is used to construct subject's 3D geometric model, according to which segment masses are determined. The determined segment masses data is taken as the yardstick to assess the errors of OpenSim scaled model. Then influence of these errors on the dynamic calculation is evaluated in the simulation of a motion in which the subject walks in an ordinary gait. Result shows that the mass error in one segment can be as large as 5.31% of overall body weight. The mean influence on calculated joint moment varies from 0.68% to 12.68% in 18 joints. In conclusion, a careful specification of segment masses will increase the accuracy of the dynamic simulation. As far as estimating human segment masses, the use of segment volume and density data can be an economical choice apart from referring to population mass distribution data.

The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of2×2,4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC) current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS) experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

Biomechanical motion simulation and kinectic analysis of human joints and muscles provide insights into Musculoskeletal disorders. OpenSim is an open-source platform that give easy access to biomechanical analysis, especially of muscles. The biomechanical analysis in OpenSim is based on pre-defined human models. Among the dozens of models available right now, none covers the muscles and joints of all the body parts. In view of the fact that most human motions are systemic, the lack of a comprehensive model prohibits synthesized and systematical biomechanical analysis. The aim of this research is to develop an OpenSim model which enables the full-chain dynamic analysis of tasks involving multi-bodies. The model is developed based on two existing models. It consists of 45 body segments, 424 muscles and 39 degrees of freedom. The model was then used to simulate an overhead drilling task. Six drilling postures are analyzed, and the estimated joint moments and muscle activations are compared.

The main “energy saving indicator,” from among nine green building indicators, evaluates the electrical power consumption of air conditioners and lighting. This study developed a small indoor personal office system with a 500W proton exchange membrane fuel cell (PEM fuel cell) as the power source, composed of LED indoor lighting, air fan, LED table lamp, notebook computer, printer, and acoustic equipment. Under continuous operations of 24h, this office system will generate 12kwh of electricity, which reduces 7.656kg of carbon dioxide output. If continuously operated for 1 year, it will generate 4,320kwh electricity, which reduces 2,756.16kg of carbon dioxide output. In addition, the side product water can be recycled as landscape water.

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