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.

Cast

original

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Cheek

Cheeks (Latin: buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside of the cheek and the teeth and gums is called the vestibule or buccal pouch or buccal cavity and forms part of the mouth. In other animals the cheeks may also be referred to as jowls.

Structure

Cheeks are fleshy in humans, the skin being suspended by the chin and the jaws, and forming the lateral wall of the human mouth, visibly touching the cheekbone below the eye. The inside of the cheek is lined with a mucous membrane (buccal mucosa, part of the oral mucosa).

During mastication (chewing), the cheeks and tongue between them serve to keep the food between the teeth.

Other animals

The cheeks are covered externally by hairy skin, and internally by stratified squamous epithelium. This is mostly smooth, but may have aborally directed papillae (e.g.: ruminants). The mucosa is supplied with secretions from the Buccal glands, which are arranged in superior and inferior groups. In carnivores, the superior buccal gland is large and discrete: the Zygomatic gland. During mastication (chewing), the cheeks and tongue between them serve to keep the food between the teeth.

Cheek (surname)

Cheek is an old family surname from Anglo-Saxon England that predates the Norman invasion. The Cheek family was among the first to immigrate to the US colonies in the early 17th century.

The family crest is a white shield with three red crescents.

Some prominent members of the Cheek family:

Cheek (disambiguation)

The cheek is the area of the face below the eyes and between the nose and the left or right ear.

Cheek or Cheeks may also refer to:

People

Other uses

See also