NRA

NRA is an abbreviation that may mean:

Localised meanings

In the Republic of China:

In France:

In Ireland:

In Japan

In the Netherlands:

In Russia:

In Tanzania:

In Uganda:

In the United Kingdom:

2013 NRA 500

The 2013 NRA 500 was NASCAR Sprint Cup Series stock car race held on April 13, 2013, at Texas Motor Speedway in Fort Worth, Texas, United States. Contested over 334 laps on the 1.5–mile (2.4 km) quad-oval, it was the seventh race of the 2013 Sprint Cup Series championship. Kyle Busch of Joe Gibbs Racing won the race, his second win of the 2013 season and first at Texas, while Martin Truex, Jr. finished second. Carl Edwards, Greg Biffle, and Joey Logano rounded out the top five.

By also winning the Friday night Nationwide Series race, Busch completed his second weekend sweep of 2013, having also accomplished this at Fontana.

Report

Background

Texas Motor Speedway is a four-turn quad-oval track that is 1.5 miles (2.4 km) long. The track's turns are banked at twenty-four degrees, while the front stretch, the location of the finish line, is five degrees. The back stretch, opposite of the front, also has a five degree banking. The racetrack has a permanent capacity of 138,122 spectators, and an infield capacity of 53,000.Greg Biffle is the defending race winner after winning the event in 2012.

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

Notes

References

Reviews

External links