Supercooled liquid water must become ice at minus 48 C (minus 55 F) not just because of the extreme cold, but because the molecular structure of water changes physically to form tetrahedron
shapes, with each water molecule loosely bonded to four others, according to the new study by University of Utah chemists Valeria Molinero and Emily Moore.
For example, a hollow cube, tetrahedron, and dodecahedron each has an Euler characteristic equal to 2.
Similarly, when four sensors are within range, the Rips complex includes a tetrahedron.
Tetrahedral carbon could be presented with a centre of mass in the gravicentre of a tetrahedron, with four specific directions oriented in such a way as to form an angle of 109[degrees] 28' between any two of the four axes.
Why was the carbon coordinate system not adopted by everybody as the fundamental coordinate system, with C-H or C-C single bond as the length unit and the angle of the tetrahedron as the angle unit?
move as a unit, which requires much less energy than rearranging the individual atoms.
I had always enormously disliked the complicated sculptures made of conglomerates of tetrahedrons and octahedrons, such as Gracehoper, The Snake Is Out, and Moses, that eventually became Smith's signature.
And we can wonder if there is more than just Wingbone or Tetrahedron (both included in the exhibition) of the kind of "soft geometric" plaster sculptures he did in the '60s.
From one angle, the intricate network of tetrahedrons and elongated octahedrons seems animalized, evoking a dog squatting back on its haunches or the one in Joan Miro's painting Dog Barking at the Moon, 1926.
Entitled Smog, 1969, it consisted of an entirely regular, altogether logical modular system of interlocking tetrahedrons stretched horizontally across the floor.
Elsevier, a world-leading provider of scientific, technical and medical information products and services, announced it will organize an extra Tetrahedron
Symposium in 2012.
There he proves that the tetrahedron
, the hexahedron (a cube), the octahedron, the dodecahedron, and the icosahedron are the only possible regular convex solids (Fig.