Abstract: An adjustable shoe includes an outsole having a middle portion hingedly attached to a forefoot portion and a heel portion. A segmented driveshaft spans from the forefoot portion of the outsole to the heel portion. Rotation of a front segment of the driveshaft causes the forefoot portion of the outsole to rotate about a hinge axis thereby adjusting a forefoot angle. A first motor is connected to the driveshaft and operable to rotate the driveshaft. A processor is in communication with the first motor and programmed to operate the first motor to provide adjustment to the shoe. A method of adjusting a shoe includes receiving a signal representing a measured force on a portion of an outsole of the shoe. If the measured force exceeds a pre-determined threshold, a motor is activated to change an angle of a forefoot portion of the outsole relative to a middle portion.

Abstract: Disclosed are multi-stage multilevel DC-DC step-down converters. Stages may include three or four switches, and switches of each stage are operated at selected duty cycles such that each stage reduces an input voltage by one-half and voltage stress on switches is reduced. In some embodiments only a single output inductor is used in an LC filter, and the inductor may be very small as compared with a conventional Buck converter. Thus, embodiments provide DC-DC step-down converters with high power density and efficiency.

Abstract: Disclosed are multilevel buck converters, and controllers and methods for operating such converters. Embodiments improve the voltage gain (Vo/Vin) of multi-level DC-DC converters, such as three-level converters, that is imposed by a duty cycle limitation in conventional approaches. According to certain embodiments, the duty cycle of switches is controlled to so that the converter output voltage is increased.

Abstract: A fluid flow-powered generator and a method for using the same are described herein. The generator has a rotatable frame, with a first wing and a second wing. The first wing and second wing are pivotally mounted to the frame to allow the angle of attack to be adjusted. A controller is also provided to direct adjustment of the angle of attack of the first wing and the second wing in a coordinated manner while the fluid flow-powered generator is in use. In certain embodiments, the fluid flow-powered generator is operable as an oscillating generator and in other embodiments, the fluid flow-powered generator is operable as a rotating generator. The rotating generator can be arranged along a horizontal axis or a vertical axis. Additionally, certain horizontally oriented generators may be operated as either oscillating generators or rotating generators.

Abstract: An airfoil system includes an airfoil body and at least one flexible strip. The airfoil body has a top surface and a bottom surface, a chord length, a span, and a maximum thickness. Each flexible strip is attached along at least one edge thereof to either the top or bottom surface of the airfoil body. The flexible strip has a spanwise length that is a function of the airfoil body's span, a chordwise width that is a function of the airfoil body's chord length, and a thickness that is a function of the airfoil body's maximum thickness.

Abstract: A wind oscillator configured for power generation is provided. The wind oscillator includes an upwardly oriented elongate rotatable support beam configured to rotate to enable the wind oscillator to be approximately oriented with respect to a wind direction, a bracket supported by the support beam, the bracket extending transversely and outward therefrom, a shaft operably connected to the bracket at a first end of the shaft, and a gear attached to a second end of the shaft.

Abstract: An airfoil system includes an airfoil body and at least one flexible strip. The airfoil body has a top surface and a bottom surface, a chord length, a span, and a maximum thickness. Each flexible strip is attached along at least one edge thereof to either the top or bottom surface of the airfoil body. The flexible strip has a spanwise length that is a function of the airfoil body's span, a chordwise width that is a function of the airfoil body's chord length, and a thickness that is a function of the airfoil body's maximum thickness.