Wind Powering America engineering, into the curriculum. Supported by local businesses and utilities, small wind turbines at rural schools also introduce the concept of energy and the need for national strategic thinking on energy issues to the communities that participate in the program. To help states and Native American communities understand their wind resources, WPA created an anemometer loan program. Participants borrow anemometers and installation equipment to measure wind resources. Anemometer data can be used to help businesses, developers, farmers, ranchers, and homeowners determine wind potential in selected areas. Each anemometer collects wind speed data in 10-minute intervals. The data aid wind farm
Pre-measure is called "σ"-additivity. Thus, what is missing for a pre-measure to be a measure is that it is not necessarily defined on a sigma-algebra (or a sigma-ring). It turns out that pre-measures give rise quite naturally to outer measures, which are defined for all subsets of the space "X". More precisely, if "μ" is a pre-measure defined on a ring of subsets "R" of the space "X", then the set function "μ" defined by is an outer measure on "X" and the measure "μ" induced by "μ" on the σ-algebra Σ of Carathéodory-measurable sets satisfies formula_4 for formula_5 (in particular,