Abstract: An ice resurfacing sled including a fuel source directing fuel to a manifold which distributes it under a regulated pressure to a plurality of orifices where it is burned in expansion chambers. The hot gas flows into a melting chamber formed by a top surface, two lateral sled runners and the surface of the ice to be melted. The melting chamber is shaped to have a reduced cross sectional area near its rear outlet to assist in maintaining the flow of heated gas beneath the sled to optimize melting. A wind screen is provided at the rear of the sled to prevent tail winds from disrupting the flow of hot gas through the melting chamber.

Abstract: An ice resurfacing sled including a fuel source directing fuel to a manifold which distributes it under a regulated pressure to a plurality of orifices where it is burned in expansion chambers. The hot gas flows into a melting chamber formed by a top surface, two lateral sled runners and the surface of the ice to be melted. The melting chamber is shaped to have a reduced cross sectional area near its rear outlet to assist in maintaining the flow of heated gas beneath the sled to optimize melting. A wind screen is provided at the rear of the sled to prevent tail winds from disrupting the flow of hot gas through the melting chamber.

Abstract: Systems and techniques for light ray concentration. In one aspect, a solar concentration assembly includes an array of light focusing elements and an array of photovoltaic devices positioned beneath the array of light focusing elements. The arrays of light focusing elements and photovoltaic devices are spaced from one another and configured to concentrate solar rays incident on the light focusing elements to the photovoltaic elements, such that solar ray communication is maintained as an angle of the assembly relative to the sun is altered by movement of the sun during a day and wherein the angle is an oblique angle for the majority of the day.