SUMMARY / RELATED TOPICS

Magnet

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, attracts or repels other magnets. A permanent magnet is an object made from a material, magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are the ones that are attracted to a magnet, are called ferromagnetic; these include the elements iron and cobalt and their alloys, some alloys of rare-earth metals, some occurring minerals such as lodestone. Although ferromagnetic materials are the only ones attracted to a magnet enough to be considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism. Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, magnetically "hard" materials, which do.

Permanent magnets are made from "hard" ferromagnetic materials such as alnico and ferrite that are subjected to special processing in a strong magnetic field during manufacture to align their internal microcrystalline structure, making them hard to demagnetize. To demagnetize a saturated magnet, a certain magnetic field must be applied, this threshold depends on coercivity of the respective material. "Hard" materials have high coercivity, whereas "soft" materials have low coercivity. The overall strength of a magnet is measured by its magnetic moment or, the total magnetic flux it produces; the local strength of magnetism in a material is measured by its magnetization. An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops; the coil is wrapped around a core of "soft" ferromagnetic material such as mild steel, which enhances the magnetic field produced by the coil. Ancient people learned about magnetism from lodestones which are magnetized pieces of iron ore.

The word magnet was adopted in Middle English from Latin magnetum "lodestone" from Greek μαγνῆτις meaning " from Magnesia", a part of ancient Greece where lodestones were found. Lodestones, suspended so they could turn, were the first magnetic compasses; the earliest known surviving descriptions of magnets and their properties are from Greece and China around 2500 years ago. The properties of lodestones and their affinity for iron were written of by Pliny the Elder in his encyclopedia Naturalis Historia. By the 12th to 13th centuries AD, magnetic compasses were used in navigation in China, the Arabian Peninsula and elsewhere; the magnetic flux density is a vector field. The magnetic B field vector at a given point in space is specified by two properties: Its direction, along the orientation of a compass needle, its magnitude, proportional to how the compass needle orients along that direction. In SI units, the strength of the magnetic B field is given in teslas. A magnet's magnetic moment is a vector.

For a bar magnet, the direction of the magnetic moment points from the magnet's south pole to its north pole, the magnitude relates to how strong and how far apart these poles are. In SI units, the magnetic moment is specified in terms of A·m2. A magnet both responds to magnetic fields; the strength of the magnetic field it produces is at any given point proportional to the magnitude of its magnetic moment. In addition, when the magnet is put into an external magnetic field, produced by a different source, it is subject to a torque tending to orient the magnetic moment parallel to the field; the amount of this torque is proportional both to the external field. A magnet may be subject to a force driving it in one direction or another, according to the positions and orientations of the magnet and source. If the field is uniform in space, the magnet is subject to no net force, although it is subject to a torque. A wire in the shape of a circle with area A and carrying current I has a magnetic moment of magnitude equal to IA.

The magnetization of a magnetized material is the local value of its magnetic moment per unit volume denoted M, with units A/m. It is a vector field, rather than just a vector, because different areas in a magnet can be magnetized with different directions and strengths. A good bar magnet may have a magnetic moment of magnitude 0.1 A•m2 and a volume of 1 cm3, or 1×10−6 m3, therefore an average magnetization magnitude is 100,000 A/m. Iron can have a magnetization of around a million amperes per meter; such a large value explains. Two different models exist for magnets: atomic currents. Although for many purposes it is convenient to think of a magnet as having distinct north and south magnetic poles, the concept of poles should not be taken literally: it is a way of referring to the two different ends of a magnet; the magnet does not have distinct south particles on opposing sides. If a bar magnet is broken into two pieces, in an attempt to separate the north and south poles, the res

Edward Peter McManaman

Edward Peter McManaman was a bishop of the Catholic Church in the United States. He served as an auxiliary bishop of the Diocese of Erie from 1948–1964. Born in Wilkes-Barre, Pennsylvania, McManaman studied for the priesthood at the Pontifical North American College in Rome and was ordained a priest there on March 12, 1927; as a priest he served as the diocesan superintendent of schools. He was named a domestic prelate with the title Monsignor on May 24, 1947. On July 24, 1948 Pope Pius XII appointed McManaman as the Titular Bishop of Floriana and Auxiliary Bishop of Erie, he was consecrated a bishop in St. Peter's Cathedral in Erie by Bishop John M. Gannon on October 28, 1948; the principal co-consecrators were Bishops William J. Hafey of Scranton and William T. McCarty, C. Ss. R. of Rapid City. McManaman served as auxiliary bishop until his death on July 18, 1964 at the age of 64

Dale Willis

Dale Jerome Willis is a retired American college and professional baseball player, a pitcher in Major League Baseball for a single season in 1963. He was listed as 5 feet 11 inches tall and 165 pounds. Willis was born in Georgia, he attended the University of Florida in Gainesville, where he played for coach Dave Fuller's Florida Gators baseball team in 1955 and 1956. As a senior in 1956, he posted three consecutive games with ten or more strikeouts, averaged 11.9 strikeouts per game, earned an All-SEC selection. He was inducted into the University of Florida Athletic Hall of Fame as a "Gator Great" in 1976. Willis was signed by the Kansas City Athletics in 1960, spent six years playing for their minor league affiliates. For the 1963 Athletics, he appeared in 25 games pitched, all in relief, posted an 0–2 win–loss record with a 5.04 earned run average. He allowed 25 bases on balls in 44 2⁄3 innings pitched, with 47 strikeouts. Willis was credited with one save, earned May 25 against the Los Angeles Angels.

He got into one game as a pinch runner. Florida Gators List of Florida Gators baseball players List of University of Florida Athletic Hall of Fame members Career statistics and player information from Baseball-Reference, or Baseball-Reference, or Pura Pelota