two-sheeted surface
1Torus — Not to be confused with Taurus (disambiguation). This article is about the surface and mathematical concept of a torus. For other uses, see Torus (disambiguation). A torus As the distance to th …
2Differential geometry of surfaces — Carl Friedrich Gauss in 1828 In mathematics, the differential geometry of surfaces deals with smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives:… …
3Multilateration — is a navigation technique based on the measurement of the difference in distance to two or more stations at known locations that broadcast signals at known times. Unlike measurements of absolute distance or angle, measuring the difference in… …
4Volume form — In mathematics, a volume form is a nowhere zero differential n form on an n manifold. Every volume form defines a measure on the manifold, and thus a means to calculate volumes in a generalized sense. A manifold has a volume form if and only if… …
5Hyperboloid — Not to be confused with Hyperbolic paraboloid. Hyperboloid of one sheet …
6Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… …
7Komatiite — Komatiites are ultramafic mantle derived volcanic rocks. They have low SiO2, low K2O, low Al2O3, and high to extremely high MgO. They were named for their type locality along the Komati River in South Africa. True komatiites are very rare and… …
8Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …
9tunnels and underground excavations — ▪ engineering Introduction Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …
10floor covering — Finish material on floors, including wood strips, parquet, linoleum, vinyl, asphalt tile, rubber, cork, epoxy resins, ceramic tile, and carpeting. Wood strip flooring, attached to a subfloor of plywood, is most popular, especially for residences …
