Cover Story
Solar Concentrators: Using Optics to Boost Photovoltaics

Valerie C. Coffey
The use of solar energy requires optimizing each part of a photovoltaic system: collection optics, the photovoltaic array, switches, controllers, current inverters, storage devices and tracking mechanics. A vast amount of research is... more>>
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A History of Human Color Vision—from Newton to Maxwell
Barry R. Masters
Color vision has attracted the attention of philosophers and scientists throughout the ages—from Aristotle to Goethe to Schrödinger. This article tracks the history of color vision over more than three centuries, with a particular emphasis on the contributions of James Clerk Maxwell. more>>
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State-of-the-Art Satellite Remote Sensing
Joan Lurie
The Earth-observation business has undergone a sea change. Commercial firms have launched satellites with sophisticated imaging capability once reserved for classified government specialists. Today, there are more high-resolution satellite images available than ever before—and they are accessible to anyone with an Internet connection. more>>