Abstract: A hybrid photovoltaic device (1) comprising a thin film solar cell (2) disposed in a first layer (21) comprising an array of vertically aligned nanowires (25), said nanowires having a junction with a first band gap corresponding to a first spectral range. The nanowires (25) form absorbing regions, and non-absorbing regions are formed between the nanowires. A bulk solar cell (3) s disposed in a second layer (31), positioned below the first layer (21), having a junction with a second band gap, which is smaller than said first band gap and corresponding to a second spectral range. The nanowires are provided in the first layer with a lateral density selected a such that a predetermined portion of an incident photonic wave-front will pass through the non-absorbing regions without absorption in the first spectral range, into the bulk solar cell for absorption in both the first spectral range and the second spectral range.

Abstract: A method of forming a semiconductor is provided and includes patterning a pad and a nanowire onto a wafer, the nanowire being substantially perpendicular with a pad sidewall and substantially parallel with a wafer surface and epitaxially growing on an outer surface of the nanowire a secondary layer of semiconductor material, which is lattice mismatched with respect to a material of the nanowire and substantially free of defects.

Abstract: A method for preventing a possible overspeed of a wind turbine rotor with at least one rotor blade is provided. The method includes detecting a yaw misalignment of the rotor, and imposing a restriction on changes of a pitch angle towards a feathered position of the at least one rotor blade after detecting the yaw misalignment. Further, a wind turbine having a rotor and a control system configured to prevent a possible overspeed of the rotor is provided.

Abstract: A method for preventing a possible overspeed of a wind turbine rotor with at least one rotor blade is provided. The method includes detecting a yaw misalignment of the rotor, and imposing a restriction on changes of a pitch angle towards a feathered position of the at least one rotor blade after detecting the yaw misalignment. Further, a wind turbine having a rotor and a control system configured to prevent a possible overspeed of the rotor is provided.

Abstract: A method of adjusting a yaw angle of a wind turbine. The wind turbine includes a nacelle that is rotatably coupled to a tower. The method includes coupling a yaw drive assembly to the nacelle for adjusting an orientation of the nacelle with respect to a direction of wind. A first sensor that is coupled to the wind turbine transmits at least a first monitoring signal that is indicative of an operating condition of the wind turbine to a control system. A yaw angle of the nacelle with respect to the direction of wind is calculated by the control system based at least in part on the first monitoring signal. The yaw drives assembly is operated to adjust a yaw of the nacelle based at least in part on the calculated yaw angle.

Abstract: A method of forming a semiconductor is provided and includes patterning a pad and a nanowire onto a wafer, the nanowire being substantially perpendicular with a pad sidewall and substantially parallel with a wafer surface and epitaxially growing on an outer surface of the nanowire a secondary layer of semiconductor material, which is lattice mismatched with respect to a material of the nanowire and substantially free of defects.

Abstract: A method of adjusting a yaw angle of a wind turbine. The wind turbine includes a nacelle that is rotatably coupled to a tower. The method includes coupling a yaw drive assembly to the nacelle for adjusting an orientation of the nacelle with respect to a direction of wind. A first sensor that is coupled to the wind turbine transmits at least a first monitoring signal that is indicative of an operating condition of the wind turbine to a control system. A yaw angle of the nacelle with respect to the direction of wind is calculated by the control system based at least in part on the first monitoring signal. The yaw drives assembly is operated to adjust a yaw of the nacelle based at least in part on the calculated yaw angle.