Related topics: nanoparticles

Making new catalysts from unique metallic alloys

Heusler alloys are magnetic materials made from three different metals that are not magnetic individually. The alloys are used broadly for their magnetic and thermoelectric properties, and their ability to regain their original ...

Kenyan wildlife policies must extend beyond protected areas

At least 15% of the world's surface is governed by laws to protect its living species, including plants, animals and fungi. But this is not enough. The most recent estimates suggest that an additional 30% of the planet's ...

Porous polymers show remarkable stability at high pressure

UmeƄ physicists in collaboration with the Technical University of Dresden and Chalmers University are the first to show high stability of the porous nanomaterial COF-1. The study is published in Angewandte Chemie, Int. Ed.

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Surface area

Surface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved then the definition of arc length of a curve. For polyhedra (objects with flat polygonal faces) the surface area is the sum of the areas of its faces. Smooth surfaces, such as a sphere, are assigned surface area using their representation as parametric surfaces. This definition of the surface area is based on methods of infinitesimal calculus and involves partial derivatives and double integration.

General definition of surface area was sought by Henri Lebesgue and Hermann Minkowski at the turn of the twentieth century. Their work led to the development of geometric measure theory which studies various notions of surface area for irregular objects of any dimension. An important example is the Minkowski content of a surface.

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