A tape head is a type of transducer used in tape recorders to convert electrical signals to magnetic fluctuations and vice versa. They can be used to read credit/debit/gift cards because the strip of magnetic tape on the back of a credit card stores data the same way that other magnetic tapes do. Cassettes, reel-to-reel tapes, 8-tracks, VHS tapes, floppy disks and modern hard drive disks all use the same principle of physics to store and read back information; the medium is magnetized in a pattern. It moves at a constant speed over an electromagnet. Since the moving tape is carrying a changing magnetic field with it, it induces a varying voltage across the head; that voltage can be amplified and connected to speakers in the case of audio, or measured and sorted into'1's and zeroes in the case of digital data. The electromagnetic arrangement of a tape head is similar for all types, though the physical design varies depending on the application - for example videocassette recorders use rotating heads which implement a helical scan, whereas most audio recorders have fixed heads.

A head consists of a core of magnetic material arranged into a doughnut shape or toroid, into which a narrow gap has been let. This gap is filled with a diamagnetic material, such as gold; this forces the magnetic flux out of the gap into the magnetic tape medium more than air would, forces the magnetic flux out of the magnetic tape medium into the gap. The flux thus induces current in the coil at that point. A coil of wire wrapped around the core opposite the gap interfaces to the electrical side of the apparatus; the basic head design is reversible - a variable magnetic field at the gap will induce an electric current in the coil, an electric current in the coil will induce a magnetic field at the gap. While a head is reversible in principle, often in practice, there are desirable characteristics that differ between the playback and recording phases. One of these is the impedance of the coil - playback preferring a high impedance, recording a low one. In the best tape recorders, separate heads are used to avoid compromising these desirable characteristics.

Having separate heads for recording and playback has other advantages, such as off-tape monitoring during recording, etc. The width of the head gap is critical - the narrower the gap, the better the head will be - a narrow gap gives much better transcription in the magnetic domain; the desirability for a narrow gap means that most practical heads are made by forming a narrow V-shaped groove in the back face of the core, grinding away the front face until the V-groove is just breached. In this way, gaps of the order of micrometres are achievable. A record head, on the other hand, has a gap six times larger than that of the replay head, this gives a larger flux to magnetise the tape; the ideal gap size in a cassette deck are. The larger gap does not affect frequency response because the'image' is made by the trailing edge of the gap. A combined record/replay head has a compromise size gap three times that of a replay only head. There are negative aspects of narrow head gaps for magnetic recording.

The narrower the head gap, the more bias signal must be used to maintain linearity of the signal on tape which in turn will reduce the high frequency headroom or SOL with slower tape speeds. Manufacturers must head gaps for this reason; the physical design of a head depends on whether it is rotating. In either case, the face of the head where the gap is must be made hard wearing and smooth to avoid excessive head wear, it can be seen that due to the construction method of the head gap, head wear will tend to widen the gap, reducing the head's performance over time. The vertical alignment of the heads must match between recording and playback for good fidelity, the gap should be as close to vertical as possible for highest frequency response. Most tape transport mechanisms will allow fine mechanical adjustment of the azimuth of the heads. Sometimes this can be achieved by automatic circuitry - the actual mechanical azimuth adjustment being carried out by taking advantage of the piezo effect of certain types of crystal material.

Rotating play heads, as used in video recorders, digital audio tape and other applications, are used to achieve a high relative head/tape speed while maintaining a low overall tape transport speed. One or more transducers are mounted on a rotating drum set at an angle to the tape; the drum spins compared to the speed that the tape moves past it, so that the transducers describe a path of stripes across the tape, rather than linearly along it as a fixed head does. The wear characteristics of such helical scan heads are more critical, polished heads and tapes are required; the electrical signals of rotating heads are coupled either inductively or capacitively - there is no direct connection to the head coils. An erase head is constructed in a similar manner to a record or replay head, but has a much larger gap, or more two large gaps; the erase head is powered during recording from a high frequency source. In some inexpensive cassette recorder designs, the erase head is a permanent magnet, mechanically moved into contact with the moving tape only during recording.

Permanent magnet erase heads are sometimes used in machines that are equipped with DC bias. Instead of feeding both the bia

The American Historical Association is the oldest and largest society of historians and professors of history in the United States. Founded in 1884, the association promotes historical studies, the teaching of history, the preservation of and access to historical materials, it publishes The American Historical Review five times a year, with scholarly articles and book reviews. The AHA is the major organization for historians working in the United States, while the Organization of American Historians is the major organization for historians who study and teach about the United States; the group received a congressional charter in 1889, establishing it "for the promotion of historical studies, the collection and preservation of historical manuscripts, for kindred purposes in the interest of American history, of history in America." As an umbrella organization for the profession, the AHA works with other major historical organizations and acts as a public advocate for the field. Within the profession, the association defines ethical behavior and best practices through its "Statement on Standards of Professional Conduct".

The AHA develops standards for good practice in teaching and history textbooks, but these have limited influence. The association works to influence history policy through the National Coalition for History; the association publishes The American Historical Review, a major journal of history scholarship covering all historical topics since ancient history and Perspectives on History, the monthly news magazine of the profession. In 2006 the AHA started a blog focused on the latest happenings in the broad discipline of history and the professional practice of the craft that draws on the staff and activities of the AHA; the association's annual meeting each January brings together more than 5,000 historians from around the United States to discuss the latest research, look for jobs, discuss how to be better historians and teachers. Many affiliated historical societies hold their annual meetings simultaneously; the association's web site offers extensive information on the current state of the profession, tips on history careers, an extensive archive of historical materials, a series of pamphlets prepared for the War Department in World War II.

The association administers two major fellowships, 24 book prizes, a number of small research grants. The early leaders of the association were gentlemen with the leisure and means to write many of the great 19th-century works of history, such as George Bancroft, Justin Winsor, James Ford Rhodes. However, as former AHA president James J. Sheehan points out, the association always tried to serve multiple constituencies, "including archivists, members of state and local historical societies and amateur historians, who looked to it - and not always with success or satisfaction - for representation and support." Much of the early work of the association focused on establishing a common sense of purpose and gathering the materials of research through its Historical Manuscripts and Public Archives Commissions. From the beginning, the association was managed by historians employed at colleges and universities, served a critical role in defining their interests as a profession; the association's first president, Andrew Dickson White, was president of Cornell University, its first secretary, Herbert Baxter Adams, established one of the first history Ph.

D. programs to follow the new German seminary method at Johns Hopkins University. The clearest expression of this academic impulse in history came in the development of the American Historical Review in 1895. Formed by historians at a number of the most important universities in the United States, it followed the model of European history journals. Under the early editorship of J. Franklin Jameson, the Review published several long scholarly articles every issue, only after they had been vetted by scholars and approved by the editor; each issue reviewed a number of history books for their conformity to the new professional norms and scholarly standards that were taught at leading graduate schools to Ph. D. candidates. From the AHR, Sheehan concludes, "a junior scholar learned what it meant to be a historian of a certain sort". Meringolo compares public history. Unlike academic history, public history is a collaborative effort, does not rely on primary research, is more democratic in participation, does not aspire to absolute "scientific" objectivity.

Historical museums, documentary editing, heritage movements and historical preservation are considered public history. Though activities now associated with public history originated in the AHA, these activities separated out in the 1930s due to differences in methodology and purpose; the foundations of public history were laid on the middle ground between academic history and the public audience by National Park Service administrators during the 1920s-30s. The academicians insisted on a perspective that looked beyond particular localities to a larger national and international perspective, that in practice it should be done along modern and scientific lines. To that end, the association promoted excellence in the area of research, the association published a series of annual reports through the Smithsonian Institution and adopted the American Historical Review in 1898 to provide early outlets for this new brand of professional scholarship. In 1896 the association appointed a "Committee of Seven" to develop a national standard for college admission requirements in the field of history.

Before this time, individual colleges defined their own entrance requirements. After substantial surveys of prevailing teaching methods, emphase

The 1975 Washington Huskies football team represented the University of Washington in the 1975 NCAA Division I football season as a member of the Pacific-8 Conference. The Huskies were led by head coach Don James in his first year, played their home games at Husky Stadium in Seattle, they finished season at 6–5 overall. Coming off a 5–6 season in 1974 under Jim Owens, James inherited a veteran squad with most of the talent on the defensive side of the ball, they would be relied upon as the offense adjusted to running from the I-formation. Fullback Robin Earl, who switched from tight end after four games last season, center Ray Pinney were the foundation for the change occurring on that side of the ball. Source: Trailing by thirteen points with three minutes remaining, defensive back Al Burleson returned an interception 93 yards for a touchdown and sophomore quarterback Warren Moon connected with Bob "Spider" Gaines for a 78-yard touchdown pass with less than a minute left to complete the comeback victory in the Apple Cup.

Washington State had dominated the second half and appeared on their way to another score when Burleson picked off John Hopkins and raced down the left sideline to the end zone with less than three minutes remaining. Coach Don James was surprised by the Cougars electing to pass instead of playing for the field goal, saying "Had they made the field goal it would have put the nail in the coffin." Following a three-and-out on Washington State's next possession, the Huskies started from their own 22. On the first play, Moon threw into coverage and the ball deflected off Leon Garrett and into the hands of teammate Gaines, who went 40 yards to score; until the Cougars had controlled the game thanks to fullback Vaughn Williams and tailback Dan Doornink, who appeared unstoppable against the Washington defense. Washington's first score came on a quarterback sneak by Chris Rowland from the one for a 7-3 lead; the Huskies scored again before halftime on a 29-yard pass from Moon to Gaines, used as a punt blocker to that point.

Moon had started the season as the starting quarterback, only to be replaced by Rowland after the offense struggled in the first few games. Moon played in eight games, started six Al Burleson Honorable Mention All-American All Pac-8 Pac-8 Player of Week Charles Jackson Pac-8 Player of Week Dan Lloyd All Pac-8 Pac-8 Player of Week Guy Flaherty Award Ray Pinney Honorable Mention All-American All Pac-8 Seven University of Washington Huskies were selected in the 1976 NFL Draft, which lasted seventeen rounds with 487 selections

The Abencerraje known as The History of the Abencerraje and the Lovely Jarifa is a novella written in sixteenth century Spain. The story was published in many versions during the 1560s. Although it was published anonymously, some scholars believe that its author could have been Jerónimo Jiménez de Urrea, it is known through different versions dated to the years 1561 and 1565 that the most polished and complete version is considered to be included in el Inventario, an elaborate miscellany prepared by Antonio de Villegas and printed in Medina del Campo. It can be found in the famous Jorge de Montemayor book, La Diana published in 1559; the book is set in a time where Muslims were discriminated against in Spain and focuses on showing how its characters, Abindarráez, a Morisco, Rodrigo de Narváez, a Christian, can get along despite having religious differences. The story touches on the human aspects such as love and chivalry portrayed by the characters rather than their religious differences; the Abencerraje begins during the time of Ferdinand VII of Spain's rule.

A revered knight, Rodrigo de Narváez, is introduced. He performed many heroic feats during the war with the Moors only in service of the king and his faith, he is named the governor of Álora as well as Antequera. In Álora, Narváez and his men go out to guard the city; the group splits up, four squires following Narváez and five squires going alone. The group of five encounters a Moorish man on a horse, they try to attack him, they are defeated, Narváez comes over to fight the man. The Moorish man is soon overpowered by Narváez however; the man falls off his horse to the ground and says that he cannot be “vanquished” by Narváez. Narváez helps the man up and asks him to explain his problems because he is noticeably troubled; the Moor introduces himself as Abindarráez the Younger. He comes from a line of the Abencerrajes of Granada; the Abencerrajes were the greatest noblemen in Granada. Everyone in the kingdom revered them; the king of Granada is told that two of the Abencerrajes and ten other men planned to assassinate the king.

The king decides to execute all involved in the plot. The people of Granada mourn the loss of two of the Abencerrajes; the king decides that no Abencerraje would be allowed to live in Granada except for Abindarráez's father and uncle. Any future Abencerraje must be raised outside of Granada and any daughter must be married outside of Granada; when Abindarráez is born, his father sends him to the governor of Cártama. He is raised alongside the governor's daughter and called her brother, they form a close bond for one another and learn that they are not related. They keep their love a secret, but the king of Granada promotes the governor of Cártama telling him to move to Coín, leaving Abindarráez behind. Jarifa tells Abindarráez of her love for him, she plans to meet with him when her father is away, so they can marry; this is why Abindarráez was riding past Álora. To show him his virtue, Rodrigo de Narváez allows Abindarráez to go to Coín if he promises to return in three days to be Narváez's captive.

Abindarráez finishes his journey to Coín where he and Jarifa marry. Jarifa tells Abindarráez of her plan to give him ownership over her father's land. Abindarráez tells Jarifa the promise he made to Narváez, instead of allowing him to go alone, Jarifa journeys with him back to Álora so she can be captive with Abindarráez. On the way back, an old man tells them the tale of one of the many memorable deeds of Narváez. While Narváez was governor of Antequera, he fell in love with a beautiful lady there, he did many things for her, however since she was married, she paid him no attention. When she asks her husband about Narváez, he speaks of him positively, how he was an amazing knight; the lady feels bad she does not love Narváez, the next day she professes her love for him, but when Narváez learns she is married, he decides to leave as to not hurt her husband. Abindarráez and Jarifa arrive at Álora. Rodrigo de Narváez takes them in, gives them food and a room, as well as treating Abindarráez's wounds he received the other day.

Abindarráez asks Narváez if he could find a solution to his troubles. Narváez sends a letter to the king of Granada explaining the situation telling him he will pardon their ransom as long as he makes Jarifa's father pardon them for marrying without his consent. Jarifa's father begrudgingly pardons both of them, they all return to Coín. There Abindarráez sends a letter to Narváez explaining how he respects him as well as sending him a gift of six thousand Zahene gold coins, four horses, four lances with gold hilts and tips, four shields. Narváez accepts everything except the coins which he sends back, he sends a letter to Jarifa explaining his love and respect for Abindarráez. The entirety of The Abencerraje contains themes of generosity; each of the characters is generous to one another. Rodrigo de Narváez allows Abindarráez to go to Coín to marry Jarifa. Many other stories of this time would see Narváez's character killing Abindarráez, or capturing him rather than allowing him to marry and come back.

When Abindarráez and Jarifa return to Álora, Narváez allows them to stay and helps solve their problems. Lastly, Abindarráez's gift to Narváez at the end of the story is a large sum of money as well as four horses and shields. Although Rodrigo de Narvaez is spoken of as brave and fearless by those who know of him in The Abencerraje, the theme of valor shines through the character of Abindarraez the Younger, a Moorish knight on his way to see his lover and complete their marriage. On his journey, he is confronted by Narvaez and his companions on

Randolph Royall Claiborne Jr. was the 5th bishop of the Episcopal Diocese of Atlanta, elected in 1952. He had served as Bishop Suffragan in the Episcopal Diocese of Alabama. Randolph was born November 7, 1906, to the Reverend Randolph Royall Claiborne, vicar of the Episcopal Church in Farmville and Mary Thomas Clark; the Claiborne family moved to Marietta, where Randolph Sr. would serve as Rector at St James' Church. Randolph Jr. attended the University of Virginia, receiving his bachelor's degree in 1928. He attended Virginia Theological Seminary in Alexandria, receiving his Master of Divinity in 1931, he was ordained deacon in June 1931 by priest in January 1932 by Bishop Mikell. From 1932 to 1938, he served as Rector of St James' Church, Georgia. From there he moved to Church of the Nativity in Huntsville, serving from 1938 to 1949 as rector. In 1949, he was elected bishop suffragan of Alabama. In 1952, he was chosen to serve as the fifth bishop of Atlanta, he was installed as diocesan bishop at a service held in St. Peter's Church in Georgia.

According to C. J. Wyatt's history of St. Peter's Church this was so that he could say he had been consecrated at "St. Peter's in Rome." Bishop Clairborne told the Annual Council Meeting of the diocese that met the weekend of his consecration of his connections to the previous bishops. Wyatt writes:"Every Bishop of Atlanta had been my friend." Bishop Nelson had visited his home during the Georgia ministry of his father. Bishop Walker was the examining chaplain. Bishop Walthour "became my friend during the years in which we both took Holy Orders." He married Clara Virginia Kinney Stribling on June 9, 1953. Bishop Claiborne retired in 1972, was given the title "Bishop Emeritus" in honor of his 20-year service to the diocese. Henry St. G. Tucker, 19th Presiding Bishop of the Episcopal Church Charles C. J. Carpenter 6th Bishop of Alabama Noble C. Powell, 9th Bishop of MarylandRandolph Claiborne was the 489th bishop consecrated in the Episcopal Church. List of Succession of Bishops for the Episcopal Church, USA Atlanta Diocese Centennial History page on Bishop Claiborne.

The Episcopal Church Annual. Morehouse Publishing: New York, NY. Upon This Rock: 150 Years in the Life of St. Peter's Church, Georgia by Dr. C. J. Wyatt Jr. St. Peter's Church: Rome, GA

The Castle of Alter do Chão, is a Portuguese medieval castle in civil parish of Alter do Chão, in the municipality of Alter do Chão, in the district of Portalegre. Between the 12th and 13th centuries the castle was a fortified settlement. Part of the vast territory of Muslim settlement, following the 13th century it was conquered by Christian forces. From bibliographic references, in 1211, the fortifications were part of the domains of the military Order of São Bento of Aviz. By 1216, from the writings of João de Almeida, King D. Afonso II issued a foral to D. Fernando Anes, but on 30 June 1249, his successor re-issued the donation to the Order of Aviz. Between 1279 and 1325, Rui de Pina noted that King D. D. Dinis did not intervene or refer to the settlement/fortification at Alter Pedroso. During this time a small hermitage was constructed to the dedication of São Bento. Between 1350 and 1450, there was no fortification/castle. During the events of the Portuguese Restoration War, in 1662, John of Austria raised the site.

In 1886, the cemetery located in the vicinity was constructed. In 1940, with the construction of the municipal motorway, the southwest line of walls was destroyed and the material used in the construction. A geodesic marker was constructed in the area, along with a lookout, followed by a reservoir by the municipal authority. On 1 June 1992, the property came under the responsibility of the Instituto Português do Património Arquitetónico, by decree 106F/92; the castle is situated on an isolated, rural hilltop 413 metres above sea level, bounded by rocky cliffs and linked by hedgerows that connect to Rua do Castelo in the village of Alter Pedroso. The remains of the walls and corbels are distributed in an elliptical area, whose major segment, 86 metres, is oriented to the north, while a minor segment of 50 metres to the south. What remains of the fortifications are: the base of a 13.5 metres wall in the west. The castle gate, composed of an ogive arch in the south is framed by 1.9–2.4 metres granite, segment of perpendicular wall to the northwest.

Within the old courtyard of the castle is a geodesic marker 412.83 metres above sea level, although the mountain reaches 420.9 metres. Below and to the west are the ruins of the Hermitage of São Bento. In the east, south of the lookout, is a small 1.9 metres deep cistern. In the southeast and southwest, are observation post for firefighters, municipal water reservoir and cemetery; the small Hermitage of São Bento, with simple, longitudinal plan includes unique 4 by 4.9 metres nave, triumphal rounded-arch and small chancel, 2.15 by 4.10 metres and remnants of a niche.47 metres. There are 13 compartiments, with 50 centimetres thick walls; the portico includes chamfered arch in tile masonry. What remains of the west to east is a small compartment to serve the atrium, 4.75 by 3.40 metres with structure for a bell, which accessible to the doorway and cemetery. Pereira, Alter do Chão in Guia de Portugal, 2, Portugal Keil, Luís, Inventário Artístico de Portugal - Distrito de Portalegre, Portugal Almeida, João de, Roteiro dos Monumentos Militares Portugueses, Portugal Nunes, António, O Castelo Estratégico Português e a Estratégia do Castelo em Portugal, Portugal