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The gores are cut from flat material and stitched together to create various shapes. Pressure suit joints are often constructed of alternating gores and convolutes of material constrained by cables or straps along the sides of the joint, producing an accordion-like structure that flexes with nearly constant volume to minimize the mechanical ...
Hollow spheres of other materials create syntactic foams with different properties: ceramic balloons e.g. can make a light syntactic aluminium foam. [3] Hollow spheres also have uses ranging from storage and slow release of pharmaceuticals and radioactive tracers to research in controlled storage and release of hydrogen. [4]
Cenosphere formed from coal combustion, magnified 400×. A cenosphere or kenosphere is a lightweight, inert, hollow sphere made largely of silica and alumina [1] and filled with air or inert gas, typically produced as a coal combustion byproduct at thermal power plants.
Sir Joseph Whitworth popularized the first practical method of making accurate flat surfaces during the 1830s, [2] using engineer's blue and scraping techniques on three trial surfaces, in what is known as Whitworth's three plates method. [3] By testing all three in pairs against each other, it is ensured that the surfaces become flat.
The earliest known mentions of spheres appear in the work of the ancient Greek mathematicians. The sphere is a fundamental surface in many fields of mathematics. Spheres and nearly-spherical shapes also appear in nature and industry. Bubbles such as soap bubbles take a spherical shape in equilibrium.
Geodesic polyhedra are a good approximation to a sphere for many purposes, and appear in many different contexts. The most well-known may be the geodesic domes, hemispherical architectural structures designed by Buckminster Fuller, which geodesic polyhedra are named after. Geodesic grids used in geodesy also have the geometry of geodesic polyhedra.
Porous glass is glass that includes pores, usually in the nanometre- or micrometre-range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses (such as in their system SiO 2-B 2 O 3-Na 2 O), followed by liquid extraction of one of the formed phases; [1] [2] through the sol-gel process; or simply by sintering glass powder.
The earliest known example is the one constructed by Crates of Mallus in Cilicia (now Çukurova in modern-day Turkey), in the mid-2nd century BC. No terrestrial globes from Antiquity have survived. An example of a surviving celestial globe is part of a Hellenistic sculpture, called the Farnese Atlas , surviving in a 2nd-century AD Roman copy in ...