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Wind power generation is one of the most effective ways to solve the electric power supply in islands. This paper presents a simple, reliable, and effective power regulating device for small-scale island wind turbine, especially for the turbine's protection during strong winds. The regulator consists of a rigid tail with an electrical control rotating an aerodynamic vane to yaw the rotor edgewise to the wind direction during high wind speeds, an electric linear actuator, and a controller. Compared with the conventional mechanical vane applied in small-scale wind turbines, such a device possesses several advantages of simple structure, high controllability, and increased reliability. The implementation of rotating the vane actively only depends on the generator speed by measuring AC electrical frequency and the output power by measuring two DC electrical quantities, and no mechanical sensors are needed. The regulator has been applied to a 15-kW prototype operating on an island for more than three years. Field test results indicate that the regulator can effectively turn the rotor out of the wind direction and its behavior agrees well with simulations. Such means of power regulating for small-scale wind turbines can be advantageously utilized compared to other mechanical or electromechanical methods. [ABSTRACT FROM PUBLISHER]

The aim of this study was to investigate canopy spectral reflectance responses to different levels of heavy metals copper (Cu), zinc (Zn), and cadmium (Cd) induced stress. Random blocks design experiment was conducted to simulate Cu, Zn, and Cd at five concentration levels. Chlorophyll and visible and near infrared canopy reflectance were measured for each treatment 56 days after seeding using chlorophyll meter SPAD-502 and spectroradiometer, respectively. New vegetative indices termed ratio of inclination angles (RIA), MERIS (the medium resolution imaging spectrometer) terrestrial chlorophyll index (MTCI), and normalized difference vegetation index (NDVI) were used to assess the response of canopy spectral reflectance to different heavy metal levels. Significant spectral variability especially in blue, red, and near infrared reflectance was observed for different heavy metal treatments. One-sample test showed significant difference for NDVI, MTCI, and RIA among five-level treatments at the 0.01 level. Correlation analysis demonstrated that the two vegetative indices (RIA and MTCI) were significantly correlated with chlorophyll meter values for Cd, Cu, and Zn treatments. However, NDVI was only significantly correlated with chlorophyll meter values for Cu and Zn treatments. Linear regression analysis also illustrated that RIA and MTCI were potential indices for predicting chlorophyll concentration with significantFtest under Cu-, Zn-, and Cd-mediated stress. [ABSTRACT FROM PUBLISHER]