Boundary (cricket)

In cricket a boundary is the edge or boundary of the playing field, or a scoring shot where the ball is hit to or beyond that point.

Edge of the field

The boundary is the edge of the playing field, or the physical object marking the edge of the field, such as a rope or fence. In low-level matches, a series of plastic cones are often used. Since the early 2000s the boundaries at professional matches are often a series of padded cushions carrying sponsors' logos strung along a rope. If it is moved during play (such as by a fielder sliding into the rope) the boundary is considered to remain at the point where that object first stood.

When the cricket ball is inside the boundary, it is live. When the ball is touching the boundary, grounded beyond the boundary, or being touched by a fielder who is himself either touching the boundary or grounded beyond it, it is dead and the batting side usually scores 4 or 6 runs for hitting the ball over the boundary. Because of this rule, fielders near the boundary attempting to intercept the ball while running or diving, often flick the ball back in to the field of play rather than pick it up directly, because their momentum could carry them beyond the rope while holding the ball. They then return to the field to pick the ball up and throw it back to the bowler.

Cricket

Cricket is a bat-and-ball game played between two teams of 11 players each on a field at the centre of which is a rectangular 22-yard-long pitch. The game is played by 120 million players in many countries, making it the world's second most popular sport. Each team takes its turn to bat, attempting to score runs, while the other team fields. Each turn is known as an innings (used for both singular and plural).

The bowler delivers the ball to the batsman who attempts to hit the ball with his bat away from the fielders so he can run to the other end of the pitch and score a run. Each batsman continues batting until he is out. The batting team continues batting until ten batsmen are out, or a specified number of overs of six balls have been bowled, at which point the teams switch roles and the fielding team comes in to bat.

In professional cricket, the length of a game ranges from 20 overs (T20) per side to Test cricket played over five days. The Laws of Cricket are maintained by the International Cricket Council (ICC) and the Marylebone Cricket Club (MCC) with additional Standard Playing Conditions for Test matches and One Day Internationals.

Cricket (magazine)

Cricket is an illustrated literary magazine for children published in the United States, founded in September 1973 by Marianne Carus whose intent was to create "The New Yorker for children."

Description

Each issue of Cricket is 48 pages. The magazine is published nine times a year (monthly, with some of the summer months combined) by the Carus Publishing Company of Peru, Illinois. Its target audience is children from 9 to 14 years old. Until March 1995, Cricket was published by the Open Court Publishing Company of La Salle, Illinois, now part of Carus.

Cricket publishes original stories, poems, folk tales, articles and illustrations by such notable artists as Trina Schart Hyman, the magazine's art director from 1973 to 1979. Carus has solicited materials from well-known authors and illustrators, including Lloyd Alexander, Isaac Bashevis Singer, Hilary Knight, William Saroyan, Ursula K. Le Guin, Eric Carle, Stacy Curtis, Wallace Tripp, Charles Ghigna and Paul O. Zelinsky. Cricket also runs contests and publishes work by its readers. Hyman contributed to the magazine until her death in 2004.

Colomban Cri-cri

The Colomban Cri-Cri (English: the chirp-chirp sound made by a cricket) is the smallest twin-engined manned aircraft in the world, designed in the early 1970s by French aeronautical engineer Michel Colomban.

Design and development

The Cri-Cri features a cantilever low-wing, a single-seat enclosed cockpit under a bubble canopy, fixed tricycle landing gear and twin engines mounted on pylons to the nose of the aircraft in tractor configuration. The aircraft is made from aluminum sheet glued to Klegecell foam. Its 4.9 m (16.1 ft) span wing employs a Wortmann 21.7% mod airfoil, and has an area of 3.1 m² (33 sq ft). The aircraft is also capable of aerobatics within the limitations of twin-engined aircraft.

Variants

Operational use

As with any homebuilt aircraft, the existing Cri-Cri planes have often been modified by their builders, departing from the original design to a varying degree, resulting in varying performance. Most versions can climb with one engine inoperative.

In June 2010, EADS partnered with Aero Composites Saintonge and the Greencri-cri Association to present an electric-powered Cri-Cri at the Green Aviation Show in Le Bourget. The modified airframe with composite components can fly for 30 minutes at 110 km/h. The aircraft uses four brushless electric motors with counter-rotating propellers, which makes the aircraft one of the world's smallest four-engine aircraft.

Boundary

Boundary (plural: boundaries) may refer to

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Mathematics and physics

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Topological manifold

In topology, a branch of mathematics, a topological manifold is a topological space (which may also be a separated space) which locally resembles real n-dimensional space in a sense defined below. Topological manifolds form an important class of topological spaces with applications throughout mathematics.

A manifold can mean a topological manifold, or more frequently, a topological manifold together with some additional structure. Differentiable manifolds, for example, are topological manifolds equipped with a differential structure. Every manifold has an underlying topological manifold, obtained simply by forgetting the additional structure. An overview of the manifold concept is given in that article. This article focuses purely on the topological aspects of manifolds.

Formal definition

A topological space X is called locally Euclidean if there is a non-negative integer n such that every point in X has a neighborhood which is homeomorphic to the Euclidean space Eⁿ (or, equivalently, to the real n-space Rⁿ, or to some connected open subset of either of two).

Boundary (topology)

In topology and mathematics in general, the boundary of a subset S of a topological space X is the set of points which can be approached both from S and from the outside of S. More precisely, it is the set of points in the closure of S, not belonging to the interior of S. An element of the boundary of S is called a boundary point of S. The term boundary operation refers to finding or taking the boundary of a set. Notations used for boundary of a set S include bd(S), fr(S), and ∂S. Some authors (for example Willard, in General Topology) use the term frontier instead of boundary in an attempt to avoid confusion with the concept of boundary used in algebraic topology and manifold theory. However, frontier sometimes refers to a different set, which is the set of boundary points which are not actually in the set; that is, S \ S.

A connected component of the boundary of S is called a boundary component of S.

If the set consists of discrete points only, then the set has only a boundary and no interior.