Rolling-element bearing

A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two bearing rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.

One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top. As the stone is pulled, the logs roll along the ground with little sliding friction. As each log comes out the back, it is moved to the front where the block then rolls on to it. It is possible to imitate such a bearing by placing several pens or pencils on a table and placing an item on top of them. See "bearings" for more on the historical development of bearings.

A rolling element rotary bearing uses a shaft in a much larger hole, and cylinders called "rollers" tightly fill the space between the shaft and hole. As the shaft turns, each roller acts as the logs in the above example. However, since the bearing is round, the rollers never fall out from under the load.

Cage (graph theory)

In the mathematical area of graph theory, a cage is a regular graph that has as few vertices as possible for its girth.

Formally, an (r,g)-graph is defined to be a graph in which each vertex has exactly r neighbors, and in which the shortest cycle has length exactly g. It is known that an (r,g)-graph exists for any combination of r ≥ 2 and g ≥ 3. An (r,g)-cage is an (r,g)-graph with the fewest possible number of vertices, among all (r,g)-graphs.

If a Moore graph exists with degree r and girth g, it must be a cage. Moreover, the bounds on the sizes of Moore graphs generalize to cages: any cage with odd girth g must have at least

vertices, and any cage with even girth g must have at least

vertices. Any (r,g)-graph with exactly this many vertices is by definition a Moore graph and therefore automatically a cage.

There may exist multiple cages for a given combination of r and g. For instance there are three nonisomorphic (3,10)-cages, each with 70 vertices : the Balaban 10-cage, the Harries graph and the Harries–Wong graph. But there is only one (3,11)-cage : the Balaban 11-cage (with 112 vertices).

The Cage (ballet)

The Cage is a ballet made by New York City Ballet ballet master Jerome Robbins to Stravinsky's Concerto in D for string orchestra, also known as the "Basel Concerto", which he was commissioned to compose on the twentieth anniversary of the chamber orchestra Basler Kammerorchester; it notably shifts between D major and minor. The premiere took place on Sunday, 10 June 1951 at the City Center of Music and Drama, New York, with décor by Jean Rosenthal, costumes by Ruth Sobatka and lighting by Jennifer Tipton. It was danced as part of City Ballet's 1982 Stravinsky Centennial Celebration.

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Daydream

Daydreaming is a short-term detachment from one's immediate surroundings, during which a person's contact with reality is blurred and partially substituted by a visionary fantasy, especially one of happy, pleasant thoughts, hopes or ambitions, imagined as coming to pass, and experienced while awake.

There are many types of daydreams, and there is no consistent definition amongst psychologists, however the characteristic that is common to all forms of daydreaming meets the criteria for mild dissociation.

Society and the negative vs. positive aspects

Negative aspects of daydreaming were stressed after human work became dictated by the motion of the tool. As craft production was largely replaced by assembly line that did not allow for any creativity, no place was left for positive aspects of daydreaming. It not only became associated with laziness, but also with danger.

For example, in the late 19th century, Toni Nelson argued that some daydreams with grandiose fantasies are self-gratifying attempts at "wish fulfillment". Still in the 1950s, some educational psychologists warned parents not to let their children daydream, for fear that the children may be sucked into "neurosis and even psychosis".

Daydreams (1915 film)

Daydreams (грезы) is a 1915 Russian silent film directed by Yevgeni Bauer.

Plot

Sergei is devastated by the death of his beloved wife Yelena. He becomes more and more obsessed by her and more and more often sees visions of her ghost. He starts an affair with an actress who looks like his dead wife but progressively drifts into madness with dramatic consequences.

Production

Daydreams was produced by A. Khanzhonkov and Co. the company created by Aleksandr Khanzhonkov, Russia's first cinema entrepreneur.

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Day Dreams (1922 film)

Daydreams is a 1922 American short comedy film directed by and featuring Buster Keaton.

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