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Dave Parker

David Gene Parker (born June 9, 1951), nicknamed "the Cobra", is an American former professional baseball player. He played in Major League Baseball as a right fielder from 1973 to 1991. A seven-time All-Star, Parker won two National League batting titles and was the 1978 National League Most Valuable Player. He was a member of two World Series championship teams, winning with the Pittsburgh Pirates in and the Oakland Athletics in.

Parker was the second professional athlete to earn an average of $1 million per year, having signed a five-year, $5 million contract in January 1979. Parker's career achievements include 2,712 hits, 339 home runs, 1,493 runs batted in and a lifetime batting average of .290. Parker was also known as a solid defensive outfielder during the first half of his career with a powerful arm, winning three straight Gold Gloves during his prime. From 1975 to 1979, he threw out 72 runners, including 26 in 1977.

Early life
Parker grew up in Cincinnati near Crosley Field, where he learned to play baseball on the stadium's parking lots. His father, Dick Parker, was a shipping clerk in a foundry. Dave Parker attended Courter Tech High School. He has said his favorite sport was football, and he starred at tailback but injured a knee in a game during his senior year and gave up the game. Also a baseball star, one of his fondest memories is playing at Western Hills High School (alma mater of Pete Rose), where he hit a home run that landed on the roof of a Frisch's restaurant.

Pittsburgh Pirates
In 1973, as a member of the Pirates Triple–A minor league affiliate, the Charleston Charlies, legend has it that Parker hit a home run that landed on a coal car on a passing train and the ball was later picked up in Columbus, Ohio. However, in a 1975 interview, Parker stated, "When I played for Charleston I always had the ambition to hit a home run onto a moving train. I really used to shoot for that. I hit a few on the tracks, but never as a train was going by." He began his major league career on July 12, 1973, with the Pittsburgh Pirates, for whom he played from 1973 to 1983. His first full season came in 1975, when he led the National League in slugging percentage (.541) and finished third in NL MVP voting.

At the 1977 MLB All-Star Game he became the only player in history to have worn batting helmets from two different teams—neither of them his own—in the same game, wearing a San Diego Padres helmet early on before swapping it out for a Cincinnati Reds one.

In 1977, he was National League batting champion, a feat he repeated in 1978 when he was named the National League MVP. This was in spite of a collision at home plate with John Stearns during a game against the Mets on June 30, 1978, in which Parker fractured his jaw and cheekbone; he wore a specially constructed facemask in order to minimize his time away from the lineup. The Pirates rewarded him with baseball's first million-dollar-per-year contract. The following year, he was an instrumental part of the Pirates' World Series championship team.

During a game in 1979, a powerful hit he made to right field was very difficult to throw into the infield, because he had "knocked the cover off the ball." One of the seams on the ball ruptured, making nearly half of the cover come loose.

Pirate fans angered by his million-dollar contract threw "nuts and bolts and bullets and batteries" at him, as pitcher Kent Tekulve stated. A typo in a news story made it appear they threw car batteries.

In 1981 at a point in his career when it looked as if he would one day rank among the game's all-time greats, Lawrence Ritter and Donald Honig included him in their book The 100 Greatest Baseball Players of All Time. The authors, noting that Parker had succeeded Roberto Clemente at the position, wrote, "Someone must have a fondness for right field in Pittsburgh."

Parker took after his Pirates teammate Willie Stargell in warming up in the on-deck circle with a sledgehammer (when most batters would use a simple lead-weighted bat).

In the early 1980s, however, Parker's hitting suffered due to injuries, weight problems and his increasing cocaine use. He became one of the central figures in a drug scandal that spread through the major leagues.

Later career
At the end of the 1983 season, Parker became a free agent and signed with the Cincinnati Reds. In Cincinnati, his hometown, he returned to the form that made him an All-Star in Pittsburgh. In 1985, he enjoyed his best season since he won the 1978 MVP with a .312 batting average and 34 home runs; he also led the National League with 125 RBIs, 42 doubles, 80 extra-base hits and 350 total bases. Parker finished second in 1985 MVP voting to Willie McGee. Parker was also the winner of the league's first-ever Home Run Derby in 1985.

Following the season, Parker was among several players who testified against a dealer in the Pittsburgh drug trials. Named as "regular users", Parker and six other players were suspended for the following season. The sentences were commuted, however, in exchange for donating ten percent of their base salaries to drug-related community service, submitting to random drug testing, and contributing 100 hours of drug-related community service.

After the 1987 season, Cincinnati traded Parker to the Oakland Athletics for José Rijo and Tim Birtsas. In Oakland, Parker was able to extend his career by spending most of his time as a designated hitter. Although injuries and age caught up to him to a degree – he hit just .257 with 12 homers in 377 at-bats in 1988 and .264 with 22 homers in 553 at-bats in 1989 – his veteran leadership was a significant factor in the A's consecutive World Series appearances which included another World Series title for Parker 1989, exactly 10 years after his first one with the Pirates in '79.

Parker signed with the Milwaukee Brewers for the 1990 season and had a solid year as the Brewers' DH with a .289 average and 21 home runs in 610 at-bats. He was even selected as a reserve for the 1990 All-Star Game. Milwaukee opted for youth however, at the end of the year and traded the aging Parker to the Angels for Dante Bichette.

Parker's last season was 1991. He played for the California Angels until late in the season before being released. The Toronto Blue Jays then signed him as insurance for the pennant race, and Parker hit .333 in limited action. Since he was acquired too late in the season, he did not qualify for inclusion on the post-season roster and was unable to play in the American League Championship Series against the Minnesota Twins, which the Blue Jays lost in five games. Parker retired at end of the season.

Retirement
Parker has served as a first-base coach for the Anaheim Angels, a batting coach for the St. Louis Cardinals in 1998, and a special hitting instructor for Pittsburgh. He owned several Popeyes Chicken franchises in Cincinnati until selling his interest in them in 2012 after 25 years.

Parker never got more than 24% of votes on Hall of Fame ballots, and his 15-year Baseball Writers' Association of America eligibility was exhausted on the 2011 ballot. He is currently under consideration for the Modern Baseball era committee. Supporters of Parker's Hall of Fame candidacy argue that Parker's involvement with the Pittsburgh drug trials has contributed to his not being voted into the Hall of Fame, which may have also harmed the candidacies of Keith Hernandez (who never received more than 10.8% and fell off the writers' ballot on his ninth try) and Tim Raines (debuted at 24.3%, but was elected on his tenth year on the ballot), serving as a precursor to those listed on the Mitchell Report not being voted into the Hall of Fame due to steroid abuse. Critics say that Parker's stats fall short of accepted standards of inclusion in the Hall. While Raines became a cause célèbre among the sabermetric community which pushed for his election, Parker does not fare as well when using advanced stats.

Parker has had both of his knees replaced due to injuries from his playing career. In 2013, he confirmed to the Pittsburgh Tribune-Review that he had been diagnosed with Parkinson's disease. He is involved in raising money to find a cure for Parkinson's disease through the Dave Parker 39 Foundation.

Parker has six children. He currently resides in Loveland, Ohio, near Cincinnati, with his wife, Kellye.

Parker was elected to the Reds Hall of Fame Class of 2014, which also included fellow Cincinnati natives Ron Oester and Ken Griffey Jr. In 2012, he was inducted into the Cincinnati Public Schools Athletic Hall of Fame. On September 3, 2022, he was inducted into the Pittsburgh Pirates Hall of Fame as part of its inaugural class.

title: Dave Parker


text: User talk:141.211.62.118

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:141.211.62.118


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Kelloggville

Kelloggville is the name of a historical community and post office located in what was once Paris Township and Wyoming Township, Kent County in the U.S. state of Michigan. The area is now within the cities of Kentwood, Wyoming, and Grand Rapids.

The community was named for Francis William Kellogg, who located the headquarters of his lumbering firm, Kellogg, White & Co., there about 1845.

The first permanent white settler was said to be Alexander Clark, who arrived in 1837.

title: Kelloggville


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Open Archives Initiative Protocol for Metadata Harvesting

The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) is a protocol developed for harvesting metadata descriptions of records in an archive so that services can be built using metadata from many archives. An implementation of OAI-PMH must support representing metadata in Dublin Core, but may also support additional representations.

The protocol is usually just referred to as the OAI Protocol.

OAI-PMH uses XML over HTTP. Version 2.0 of the protocol was released in 2002; the document was last updated in 2015. It has a Creative Commons license BY-SA.

History
In the late 1990s, Herbert Van de Sompel (Ghent University) was working with researchers and librarians at Los Alamos National Laboratory (US) and called a meeting to address difficulties related to interoperability issues of e-print servers and digital repositories. The meeting was held in Santa Fe, New Mexico, in October 1999. A key development from the meeting was the definition of an interface that permitted e-print servers to expose metadata for the papers it held in a structured fashion so other repositories could identify and copy papers of interest with each other. This interface/protocol was named the "Santa Fe Convention".

Several workshops were held in 2000 at the ACM Digital Libraries conference, at the 1st ACM/IEEE-CS joint conference on Digital libraries and elsewhere to share the ideas from the Santa Fe Convention. It was discovered at the workshops that the problems faced by the e-print community were also shared by libraries, museums, journal publishers, and others who needed to share distributed resources. To address these needs, the Coalition for Networked Information and the Digital Library Federation provided funding to establish an Open Archives Initiative (OAI) secretariat managed by Herbert Van de Sompel and Carl Lagoze. The OAI held a meeting at Cornell University (Ithaca, New York) in September 2000 aimed to improve the interface developed at the Santa Fe Convention. The specifications were refined over e-mail.

OAI-PMH version 1.0 was introduced to the public in January 2001 at a workshop in Washington D.C., and another in February in Berlin, Germany. Subsequent modifications to the XML standard by the W3C required making minor modifications to OAI-PMH resulting in version 1.1. The current version, 2.0, was released in June 2002. It contained several technical changes and enhancements and is not backward compatible.

OAI workshops
From 2001 CERN, and later in collaboration with University of Geneva, has organized bi-annual OAI workshops, which over time have developed to cover most aspects of open science. Since 2021 the workshop series is named the Geneva Workshop on Innovations in Scholarly Communication, with the nick name OAI reflecting its origin.

Uses
Some commercial search engines use OAI-PMH to acquire more resources. Google initially included support for OAI-PMH when launching sitemaps, however decided to support only the standard XML Sitemaps format in May 2008. In 2004, Yahoo! acquired content from OAIster (University of Michigan) that was obtained through metadata harvesting with OAI-PMH. Wikimedia uses an OAI-PMH repository to provide feeds of Wikipedia and related site updates for search engines and other bulk analysis/republishing endeavors. Especially when dealing with thousands of files being harvested every day, OAI-PMH can help in reducing the network traffic and other resource usage by doing incremental harvesting. NASA's Mercury metadata search system uses OAI-PMH to index thousands of metadata records from Global Change Master Directory (GCMD) every day.

The mod_oai project is using OAI-PMH to expose content to web crawlers that is accessible from Apache Web servers.

OAI-PMH has later been applied to sharing of scientific data.

Software
OAI-PMH is based on a client–server architecture, in which "harvesters" request information on updated records from "repositories". Requests for data can be based on a datestamp range, and can be restricted to named sets defined by the provider. Data providers are required to provide XML metadata in Dublin Core format, and may also provide it in other XML formats.

A number of software systems support the OAI-PMH, including Fedora, EThOS from the British Library, GNU EPrints from the University of Southampton, Open Journal Systems from the Public Knowledge Project, Desire2Learn, DSpace from MIT, HyperJournal from the University of Pisa, Digibib from Digibis, MyCoRe, Koha, Primo, DigiTool, Rosetta and MetaLib from Ex Libris, ArchivalWare from PTFS, DOOR from the eLab in Lugano, Switzerland, panFMP from the PANGAEA data library, SimpleDL from Roaring Development, and jOAI from the National Center for Atmospheric Research.

Archives
A number of large archives support the protocol including arXiv and the CERN Document Server.


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Category:Kent County, Michigan

Articles related to Kent County in the U.S. state of Michigan.

title: Category:Kent County, Michigan


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Hawksbill Station

Hawksbill Station is a science fiction novel by American writer Robert Silverberg. The novel is an expanded version of a short story first published in Galaxy Science Fiction in August 1967. The novel was published in 1968 and was released in the United Kingdom under the title The Anvil of Time.

Synopsis
Hawksbill Station was a penal colony in the Cambrian Period created by an authoritarian United States government, using time travel to exile rebels and political dissidents into the past. The colony houses only male exiles, who are sent there as a "humane" alternative to execution. The machine only works one way, leaving prisoners marooned in the past.

The prison is set in a barren coastal area. The novel focuses on the relationships between the main character, the de facto leader of the colony, and his nemesis in the government, Jacob “Jack” Bernstein, both of whom were leading dissidents. It also explores the petty ideological differences among the prisoners and the confused circumstances leading to the establishment of the authoritarian government.

The prisoners, all middle-aged or elderly, are surprised by the arrival of a much younger prisoner. The newcomer, supposedly an economist, is questioned about economic theory and political ideology. His answers reveal his essential ignorance of both. This ignorance, combined with his youth, cause the prisoners to wonder if he is, in fact, a political prisoner or a common criminal, exiled for a heinous crime.

When the newcomer arrives via the time machine a second time, it is revealed that he is a police officer of a new government that overthrew the authoritarian government but was unrelated to the dissident movements of the exiles. The new government discovered the existence of Hawksbill Station and a way to travel from past to future, making it possible to retrieve prisoners from the colony. The newcomer has been sent to evaluate the prisoners and to recommend whether they are appropriate for retrieval.

With return now possible, the leader of the exiles realizes that he is a time traveler of a different sort. The struggle against the authoritarian government, his life's work, is over. His closest friends in the movement, as well as his most bitter enemies, are dead. He is tempted to visit the newcomer's future, but Hawksbill Station is now the only existence he knows.

Reception
Algis Budrys said that Hawksbill Station was Silverberg's best story.

Hawksbill Station was credited by Jeff Vogel, a small indie game developer, as having influenced the design for his game Exile: Escape from the Pit, saying that while most of the game's plotlines were his, this classic short story helped shape his ideas.

title: Hawksbill Station


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Treaty of Gulistan

The Treaty of Gulistan (also spelled Golestan: Гюлистанский договор; ) was a peace treaty concluded between the Russian Empire and Qajar Iran on 24 October 1813 in the village of Gulistan (now in the Goranboy District of Azerbaijan) as a result of the first full-scale Russo-Persian War (1804 to 1813). The peace negotiations were precipitated by the successful storming of Lankaran by General Pyotr Kotlyarevsky on 1 January 1813. It was the first of a series of treaties (the last being the Akhal Treaty) signed between Qajar Iran and Imperial Russia that forced Persia to cede the territories that formerly were part of Iran.

The treaty confirmed the ceding and inclusion of what is now Dagestan, eastern Georgia, most of the Republic of Azerbaijan, and parts of northern Armenia from Iran into the Russian Empire.

The text was prepared by the British diplomat Sir Gore Ouseley, who served as a mediator and wielded a significant degree of influence in the Persian court. It was signed by Nikolai Rtischev for Russia and Mirza Abolhassan Khan Ilchi for Persia.

The result of the treaty was the transfer of the bulk of Iran's Caucasian territories to the Russian Empire. The treaty also directly contributed to the outbreak of the next war of the 19th century: the Russo-Persian War (1826–1828), in which the Iranian forces were defeated once more. In the following Treaty of Turkmenchay, Qajar Iran lost possession of its last remaining Caucasian territories, comprising modern-day Armenia and the remaining part of modern-day Azerbaijan. By 1828, Iran had lost by both treaties all of those integral territories in Transcaucasia and the North Caucasus. The area north of the Aras River, including the territory of the contemporary nations of Georgia, Azerbaijan, Armenia and the North Caucasian Republic of Dagestan, were part of Iran until they were occupied by Russia during the 19th century.

As a further direct result and consequence of the Treaty of Gulistan in combination with the 1828 Treaty of Turkmenchay, the formerly Iranian territories came under the Russian, and later the Soviet control for approximately 180 years, and Dagestan remains a constituent republic within the Russian Federation to this day. Comprising most of the territory ceded in Gulistan and Turkmenchay treaties, three separate nations would gain independence following the dissolution of the Soviet Union in 1991: Georgia, Azerbaijan, and Armenia.

Background
In 1801, the Russian Empire had sworn in a new tsar, Alexander I, who was eager to expand Russia's control over its neighboring territories. A few years previously in Iran, Fath Ali Shah Qajar also became the new shah after the assassination of his uncle, Agha Mohammad Khan Qajar, in 1797. During his reign, Agha Mohammad Khan had defeated and re-subordinated the Afsharid/Safavid vassals and subjects in the regions of modern-day eastern Georgia, Armenia, southern Dagestan, and Azerbaijan, and claimed those areas as rightfully belonging to Persia. During and after the Battle of Krtsanisi in 1795, he had regained full control over eastern Georgia, Dagestan, Armenia, and Azerbaijan. Several years later, after Agha Mohammad Khan was assassinated in Shusha and Heraclius II of Georgia had died as well. Russia, wishing expand its territory and trade, capitalized on the opportunity to annex eastern Georgia. The Persian court attempted to align itself with France in 1801 in order to establish a better position in case of war with Russia, but those attempts were unsuccessful. Later, as both Russia and Britain were engaged in the Napoleonic Wars, Fath Ali Shah instead brokered a deal with Britain to provide Persia with military support from British troops in exchange for preventing any European country from entering India. Following the agreement, Persia entered into the First Russo-Persian War against a militarily-preoccupied Russia, which was heavily invested in the Napoleonic Wars.

The primary motive of the Persian court when entering the war was to reassert its control over Georgia and to ensure the protection of the rest of its northwestern borders. However, Fath Ali Shah had also heard about the atrocities being committed by Russian Commanders in Georgia "through massive extortion and maladministration".

Numerically, the Persian forces had a considerable advantage during the war, wielding an army as much as five times larger than the Russians in the Caucasus. However, the Persian forces lagged behind technologically and were poorly trained, a problem that the Persian government did not recognize until far later. Despite these significant disadvantages, the fighting continued in northern Persia, Azerbaijan and in regions of Georgia. Persian court went so far as to declare a jihad against the Russian Empire and called upon its Iranian subjects to maintain unity. The Persian court also requested military and financial aid from France's Napoleon in light of the Franco-Persian alliance. Although France promised to support Iran's ambitions and help it regain its recently-lost territory of Georgia, ultimately Napoleon left Persia unassisted given France's relations with Russia were more important after the two countries signed the Treaty of Tilsit in 1807. The turning point of the war came on 31 October 1812 during the Battle of Aslanduz, in which the Persian army suffered a decisive defeat. Following the battle, Fath Ali Shah had no option but to sign the Treaty of Gulistan.

According to Cambridge History of Iran: Even when rulers on the plateau lacked the means to effect suzerainty beyond the Aras, the neighboring Khanates were still regarded as Iranian dependencies. Naturally, it was those Khanates located closest to the province of Azarbaijan which most frequently experienced attempts to re-impose Iranian suzerainty: the Khanates of Erivan, Nakhchivan, and Qarabagh across the Aras, and the cis-Aras Khanate of Talish, with its administrative headquarters located at Lankaran and therefore very vulnerable to pressure, either from the direction of Tabriz or Rasht. Beyond the Khanate of Qarabagh, the Khan of Ganja and the Vali of Gurjistan (ruler of the Kartli-Kakheti kingdom of south-east Georgia), although less accessible for purposes of coercion, were also regarded as the Shah's vassals, as were the Khans of Shakki and Shirvan, north of the Kura River. The contacts between Iran and the Khanates of Baku and Qubba, however, were more tenuous and consisted mainly of maritime commercial links with Anzali and Rasht. The effectiveness of these somewhat haphazard assertions of suzerainty depended on the ability of a particular Shah to make his will felt, and the determination of the local khans to evade obligations they regarded as onerous.

Terms

 * 1) "Russia by this instrument was confirmed in possession of all the khanates – Karabagh, Ganja, Shekeen, Shirvan, Derbend, Kouba, and Baku, together with part of Talish and the fortress of Lenkoran. Persia further abandoned all pretensions to Daghestan, Georgia, Mingrelia, Imeretia, and Abkhazia."
 * 2) The lands include:
 * 3) All the cities, towns, and villages of Georgia, including all the villages and towns on the coast of the Black Sea, such as:
 * 4) Megrelia,
 * 5) Abkhazia,
 * 6) Imeretia,
 * 7) Guria;
 * 8) Almost all cities, towns, and villages of the khanates in the South Caucasus and partly North Caucasus:
 * 9) Baku khanate,
 * 10) Shirvan Khanate,
 * 11) Derbent Khanate,
 * 12) Karabakh khanate,
 * 13) Ganja khanate,
 * 14) Shaki Khanate,
 * 15) Quba Khanate,
 * 16) part of the Talysh Khanate;
 * 17) Iran loses all rights to navigate the Caspian Sea, and Russia is granted exclusive rights to station its military fleet in the Caspian Sea.
 * 18) Both countries agree on the establishment of free trade, with Russians having free access to conduct business anywhere in Iran.
 * 19) Iran is also given complete and free access to Russia, but both must pay a 5% ad valorem tax on any items imported into each respective country, thus being seen as a light import/export duty tax.
 * 20) Russia, in return, promises to support Abbas Mirza as heir to the Persian throne after the death of Fath Ali Shah.

Assessment
Even today, Iran officially sees it and the later Treaty of Turkmenchay as some of its most humiliating treaties ever signed. The treaty is also regarded by Iranians as the main reason why Fath Ali Shah is seen as one of Iran's most incompetent rulers in memory. Scholars in Azerbaijan point out that the Karabakh Khanate, where the treaty was signed, had pursued an independent foreign policy as early as 1795, when "Ibrahim Khalil Khan, the wali of Qarabagh, fearing for his independence, warned Sultan Selim III of Agha Muhammad Khan Qajar's ambitions to subdue Azerbaijan and later Qarabagh, Erivan and Georgia. In the same year Muhammad Khan, the hakim of Erivan, also wrote a letter to Selim III, alerting him to Agha Muhammad's 'aggression, and seeking Ottoman protection".

Imperial Russian historians maintained that Russia's absorption of the Transcaucasia shielded the local populations from the constant Iranian and Ottoman invasions, and that the Christian nations of the Caucasus were liberated from Muslim repression, which ensured peace and stability in the region.

Vital to the signing of the treaty was the agreement made by Fath Ali Shah with Britain. With the defeat in the Russo-Persian War, the Shah understood that another attack by the Russians was almost inevitable. Britain saw such a war as unwinnable for the Persians, and so took advantage of Persia's weakness to strengthen their foreign affairs in the region. Using their new-found diplomatic connections with the British, Persia established the Treaty of Defensive Alliance in 1812, which promised that Britain would "offer a defensive alliance against further Russian encroachments". Its terms essentially stated that Persia would defend against any European army entering India, which stationed British troops, and in return, Britain would provide military and financial against any future Russian attack.

Aftermath
The treaty of Gulistan did not answer vital questions such as whether the Persian army would be disarmed or be able to regroup. It was obvious to both sides that Persia would potentially attempt to reclaim the territories in the future, given the Persian court considered the captured regions rightfully Iranian and opposed Russia's repressive treatment of the Caucasian populations. The war had become costly in terms of finance and manpower, so the Treaty of Gulistan led to over a decade of relative peace (1813–1826) between Russia and Persia, primarily for the clause regarding trade: both governments saw substantial potential in it. Permanent diplomatic missions were set up in Persia as well as in Russia in order to keep trade open for as long as possible. The tensions remained, however, as the governments of both countries understood that the terms of the treaty were vague, and that nothing was written about provisions for the military, mainly to prevent Persia from trying to regain the regions of Georgia or the Caucasus, thus leaving open the possibility of another future war. It is likely that neither the Iranian Shah nor the Russian Tsar regarded the treaty of Gulistan as definitive.

According to Prof. Timothy C. Dowling: Iran lost all its territories north of the Aras river, which included Daghestan, all of Georgia, and parts of Armenia and Azerbaijan. (...) The shah also surrendered Iranian rights to navigate the Caspian Sea and granted Russia exclusive rights to maintain a military fleet there, with capitulatory rights to trade within Iran. Russia in return promised to support Crown Prince Abbas Mirza as heir to the Iranian throne. Following the disastrous Russo-Iranian War of 1804–1813, Iranian leadership considered the Treaty of Gulistan more as a truce that allowed Iran to regroup. (...) Continued Russian encroachment into the southern Caucasian territories as well as the mistreatment of Muslim populations had seriously strained Russo-Iranian relations. General Aleksei Yermolov, the New Russian commander in chief in the Caucasus, shared his predecessor Tsitsianov's worldview toward "Asiatics" and was committed to war as a means of achieving Russia's political goals. In May 1826, Russia, therefore, occupied Mirak, in the Erivan Khanate, in violation of the Treaty of Gulistan, [sparking the next and final bout of hostilities between the two].

According to Prof. William Bayne Fisher (et al.): British mediation made it possible for the two sides to negotiate a peace treaty which was signed on 14 Oktober 1813, at the village of Gulistan. By its terms, Iran lost many of its Caucasian provinces, including Qarabagh and Ganja, Shirvan and Baku, Georgia, and parts of Talish. No power other than Russia was permitted warships on the Caspian Sea. This provision left the Persian shores vulnerable to Russian attack. The treaty also dealt with commercial matters and with the establishment of permanent diplomatic missions. Perhaps the most dangerous provisions of the Gulistan treaty were those that promised Russian recognition and support of the legitimate heir to the Persian throne and those which delineated the border between the two states. These provisions were so vague as to invite misinterpretation and conflict.

Another consequence of Persia's losses to Russia and the subsequent treaties of Gulistan and Turkemenchay was the separation of the Azerbaijani and Talysh people from their brethren in Iran.

The area to the North of the river Aras, amongst which is the territory of the contemporary nations of Georgia, Azerbaijan, Armenia and the North Caucasian Republic of Dagestan, were Iranian territory until they were occupied by Russia in the course of the 19th century.

Precursor to Second Russo-Persian War of 1826–1828
The Treaty of Gulistan did not resolve the possibility of a future conflict between Russia and Iran. Russia's priority before the war was Europe and the Napoleonic Wars, which explains the relatively small number of troops that Russia dedicated to the Russo-Persian War. The Treaty of Gulistan can be primarily regarded as a way for both countries to "gain a breath" so that they could focus on other issues. After the treaty was signed, Persia began rapidly building up its army once more, as Fath Ali Shah was fully devoted to regaining the lost territories. It is therefore not surprising that Fath Ali Shah ordered his military commander, Abbas Mirza, to start training troops in 1823, three years before the following Russo-Persian War. Furthermore, the Persian clergy publicly announced that the jihad against Russia was not over. In 1826, Persia, with British support, once again invaded the territories lost to Russia. The second war lasted two years, and Persia lost 35,000 troops to Russia's 8,000. Persia's defeat culminated in the Treaty of Turkmenchay, which resulted in further losses of modern-day Armenia and the remaining parts of Azerbaijan.

title: Treaty of Gulistan


text:
Belgrano, Buenos Aires

Belgrano is a northern and leafy barrio or neighborhood of Buenos Aires, Argentina.

Location
The barrio of Palermo is to the southeast; Núñez is to the northwest; Coghlan, Villa Urquiza, Villa Ortúzar and Colegiales are to the southwest.

History
Belgrano was named after Manuel Belgrano, a politician and military leader who created the national flag of Argentina. In 1820, at Belgrano's death, Buenos Aires' legislature introduced a law to name the next town to be founded after him. This happened in 1855, when the Buenos Aires government, fearful that relatives of Juan Manuel de Rosas would dispute the governmental decision to expropriate Rosas' lands, laid down a new town on part of it and named it Belgrano. The town was declared a city shortly thereafter, due to its booming growth, and in 1880 it became the nation's capital for a few weeks, because of the dispute between the national government and Buenos Aires province for the status of the city of Buenos Aires. It was in Belgrano that the law declaring Buenos Aires as Argentina's federal capital was issued. In 1887, the federal district was enlarged by the annexation of the towns (partidos) of Belgrano and Flores.

Subsections

Belgrano is an upper-middle-class neighborhood that can be roughly divided into Belgrano R, Belgrano C, central Belgrano, and Lower Belgrano (Bajo Belgrano). The heart of the barrio pulses with life on its main thoroughfare, Avenida Cabildo, which runs Northwest to Southeast; the subway (subte) Line D follows its route.

Avenida Cabildo carries heavy automobile traffic, and features corner cafés, grocery stores, movie theaters, specialty shops, clothing boutiques, bookstores, and other retail venues. Thanks to its wide sidewalks, pedestrians are especially numerous on weekend afternoons as Porteños (residents of Buenos Aires) from various areas of the city come to shop.

Most of the neighborhood's densest housing is located in the vicinity of Cabildo. High-rise luxury apartment buildings are clustered on the leafy streets surrounding the Universidad de Belgrano, a private liberal-arts university.

West of Crámer avenue, "Belgrano R" is chiefly residential and lower-density in nature, characterized by calm streets lined with large, mature shade trees. Most buildings in this section are detached single-family homes that follow North American architectural styles; some residences have sizable backyards with swimming pools. This section is favored by wealthy Argentines and expatriate businesspeople, and also by the embassies of Egypt, Japan, Republic of Korea, Tunisia, United Arab Emitates, among others. Some expensive private, bilingual schools are located in the area.

"Belgrano C" is also home to Buenos Aires's small Chinatown. The district is crowded with restaurants and specialty grocery stores catering to Asian-Argentines and to the general public.

Transportation
Other than Cabildo, avenues Libertador, Luis Maria Campos, Crámer, Ricardo Balbín (formerly known as del Tejar), and Figueroa Alcorta run parallel to the riverbank, while Federico Lacroze, Juramento, Monroe and Congreso run from the riverbank to the Southwest direction. Belgrano is served by the Buenos Aires metro line D, many bus lines (notably Colectivo 60), and two commuter rail lines. Approximately 1.5 km to the west of Belgrano lies Avenida General Paz, a major limited-access freeway that defines the city limits of Buenos Aires proper. Beyond this avenue lie the suburbs of Vicente Lopez, Florida and Olivos.

Notable attractions
The lush park Barrancas de Belgrano was designed by the famous French-Argentine landscape/park architect Carlos Thays, who designed many open spaces throughout Buenos Aires. Several blocks north of the Belgrano University, Barrancas de Belgrano spans several city blocks and is overlooked by highrise upper-middle class apartment buildings.

On Manuel Belgrano square, a local artisan fair is held regularly, and becomes especially vibrant on weekends. It features a small bust of Manuel Belgrano on its middle spot.

In the edge of the plaza lies the Inmaculada Concepción church, called "La Redonda" (the round one) by locals because of its circular plan. Many weddings are celebrated in this church in the afternoon hours. Two museums are also across Juramento and Cuba streets: Larreta and Sarmiento, respectively. Larreta museum focus on Spanish art. It is located on the former private residence of writer Enrique Larreta, designed by architect Ernesto Bunge on 1882. It features a well kept Andalusian garden. Historical Museum Sarmiento exhibits some objects belonging to former presidents Domingo Faustino Sarmiento and Nicolás Avellaneda. It is located in what used to be Belgrano townhall, where the national congress held its sessions while Belgrano was the capital of the Argentine republic. Nearby, going down to Lower Belgrano (Bajo Belgrano), appears the Barrancas de Belgrano, three squares along together, older Rio de la Plata River natural terraces. Two blocks away, in Lower Bergrano there is the Estadio de Excursionistas, the local football team. Although neighboring Nuñez is widely known as the home of River Plate, its landmark stadium River Plate Stadium—also home of the Argentina national football team—is located within the boundaries of Belgrano.

title: Belgrano, Buenos Aires


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Carmack

Carmack is a surname derived from the Irish given name "Cormac". Notable people with the surname include:

 * Adrian Carmack (born 1969), game artist, cofounder of id Software
 * Chris Carmack (born 1980), American actor
 * Edward W. Carmack (1858–1908), American politician
 * George Carmack (1860–1922), American discoverer of gold in the Klondike region
 * Howard Carmack, Internet spammer
 * John Carmack (born 1970), American game programmer, co-founder of id Software
 * Justin Carmack (1981-2000), American child actor
 * Kate Carmack (1862–1920), First Nation woman
 * Kona Carmack (born 1976), American model

title: Carmack


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Talk:Functional constipation

Spelling Errors in Reference
I tried to Fix it, but I was having Difficulty figuring out how to do that, if someone sees this before I Fix it, perhaps You (Anyone...) could. Now, on to The Details, in the 1 Reference, there are 2 Spelling Errors: ^ a b Americal College of Gastroenterology: Fuinctional Bowel Disorders - Just needs Someone to Fix "Americal" to "America" and "Fuinctional" to "Functional" - All Minus the Bold Text I Added to Quote, so it would Stand Out here in/on the Discussions Page. Thank You, - DanielRJ/DanielRJ (talk) 14:51, 10 October 2011 (UTC)

title: Talk:Functional constipation


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Transparent ceramics

Many ceramic materials, both glassy and crystalline, have found use as optically transparent materials in various forms from bulk solid-state components to high surface area forms such as thin films, coatings, and fibers. Such devices have found widespread use for various applications in the electro-optical field including: optical fibers for guided lightwave transmission, optical switches, laser amplifiers and lenses, hosts for solid-state lasers and optical window materials for gas lasers, and infrared (IR) heat seeking devices for missile guidance systems and IR night vision. In commercial and general knowledge domains, it is commonly accepted that transparent ceramics or ceramic glass are varieties of strengthened glass, such as those used for the screen glass on an iPhone.

While single-crystalline ceramics may be largely defect-free (particularly within the spatial scale of the incident light wave), optical transparency in polycrystalline materials is limited by the amount of light that is scattered by their microstructural features. The amount of light scattering therefore depends on the wavelength of the incident radiation, or light.

For example, since visible light has a wavelength scale on the order of hundreds of nanometers, scattering centers will have dimensions on a similar spatial scale. Most ceramic materials, such as alumina and its compounds, are formed from fine powders, yielding a fine grained polycrystalline microstructure that is filled with scattering centers comparable to the wavelength of visible light. Thus, they are generally opaque as opposed to transparent materials. Recent nanoscale technology, however, has made possible the production of (poly)crystalline transparent ceramics such as alumina Al2O3, yttria alumina garnet (YAG), and neodymium-doped YAG.

Introduction
Transparent ceramics have recently acquired a high degree of interest and notoriety. Basic applications include lasers and cutting tools, transparent armor windows, night vision devices (NVD), and nose cones for heat seeking missiles. Currently available infrared (IR) transparent materials typically exhibit a trade-off between optical performance and mechanical strength. For example, sapphire (crystalline alumina) is very strong, but lacks full transparency throughout the 3–5 micrometer mid-IR range. Yttria is fully transparent from 3–5 micrometers, but lacks sufficient strength, hardness, and thermal shock resistance for high-performance aerospace applications. Not surprisingly, a combination of these two materials in the form of the yttria-alumina garnet (YAG) has proven to be one of the top performers in the field.

In 1961, General Electric began selling transparent alumina Lucalox bulbs. In 1966, GE announced a ceramic "transparent as glass", called Yttralox. In 2004, Anatoly Rosenflanz and colleagues at 3M used a "flame-spray" technique to alloy aluminium oxide (or alumina) with rare-earth metal oxides in order to produce high strength glass-ceramics with good optical properties. The method avoids many of the problems encountered in conventional glass forming and may be extensible to other oxides. This goal has been readily accomplished and amply demonstrated in laboratories and research facilities worldwide using the emerging chemical processing methods encompassed by the methods of sol–gel chemistry and nanotechnology.

Many ceramic materials, both glassy and crystalline, have found use as hosts for solid-state lasers and as optical window materials for gas lasers. The first working laser was made by Theodore H. Maiman in 1960 at Hughes Research Laboratories in Malibu, who had the edge on other research teams led by Charles H. Townes at Columbia University, Arthur Schawlow at Bell Labs, and Gould at TRG (Technical Research Group). Maiman used a solid-state light-pumped synthetic ruby to produce red laser light at a wavelength of 694 nanometers (nm). Synthethic ruby lasers are still in use. Both sapphires and rubies are corundum, a crystalline form of aluminium oxide (Al2O3).

Crystals
Ruby lasers consist of single-crystal sapphire alumina (Al2O3) rods doped with a small concentration of chromium Cr, typically in the range of 0.05%. The end faces are highly polished with a planar and parallel configuration. Neodymium-doped YAG (Nd:YAG) has proven to be one of the best solid-state laser materials. Its indisputable dominance in a broad variety of laser applications is determined by a combination of high emission cross section with long spontaneous emission lifetime, high damage threshold, mechanical strength, thermal conductivity, and low thermal beam distortion. The fact that the Czochralski crystal growth of Nd:YAG is a matured, highly reproducible and relatively simple technological procedure adds significantly to the value of the material.

Nd:YAG lasers are used in manufacturing for engraving, etching, or marking a variety of metals and plastics. They are extensively used in manufacturing for cutting and welding steel and various alloys. For automotive applications (cutting and welding steel) the power levels are typically 1–5 kW. In addition, Nd:YAG lasers are used in ophthalmology to correct posterior capsular opacification, a condition that may occur after cataract surgery, and for peripheral iridotomy in patients with acute angle-closure glaucoma, where it has superseded surgical iridectomy. Frequency-doubled Nd:YAG lasers (wavelength 532 nm) are used for pan-retinal photocoagulation in patients with diabetic retinopathy. In oncology, Nd:YAG lasers can be used to remove skin cancers. These lasers are also used extensively in the field of cosmetic medicine for laser hair removal and the treatment of minor vascular defects such as spider veins on the face and legs. Recently used for dissecting cellulitis, a rare skin disease usually occurring on the scalp. Using hysteroscopy in the field of gynecology, the Nd:YAG laser has been used for removal of uterine septa within the inside of the uterus. In dentistry, Nd:YAG lasers are used for soft tissue surgeries in the oral cavity.

Glasses
Glasses (non-crystalline ceramics) also are used widely as host materials for lasers. Relative to crystalline lasers, they offer improved flexibility in size and shape and may be readily manufactured as large, homogeneous, isotropic solids with excellent optical properties. The indices of refraction of glass laser hosts may be varied between approximately 1.5 and 2.0, and both the temperature coefficient of n and the strain-optical coefficient may be tailored by altering the chemical composition. Glasses have lower thermal conductivities than the alumina or YAG, however, which imposes limitations on their use in continuous and high repetition-rate applications.

The principal differences between the behavior of glass and crystalline ceramic laser host materials are associated with the greater variation in the local environment of lasing ions in amorphous solids. This leads to a broadening of the fluorescent levels in glasses. For example, the width of the Nd3+ emission in YAG is ~ 10 angstroms as compared to ~ 300 angstroms in typical oxide glasses. The broadened fluorescent lines in glasses make it more difficult to obtain continuous wave laser operation (CW), relative to the same lasing ions in crystalline solid laser hosts.

Several glasses are used in transparent armor, such as normal plate glass (soda-lime-silica), borosilicate glass, and fused silica. Plate glass has been the most common glass used due to its low cost. But greater requirements for the optical properties and ballistic performance have necessitated the development of new materials. Chemical or thermal treatments can increase the strength of glasses, and the controlled crystallization of certain glass compositions can produce optical quality glass-ceramics. Alstom Grid Ltd. currently produces a lithium di-silicate based glass-ceramic known as TransArm, for use in transparent armor systems. It has all the workability of an amorphous glass, but upon recrystallization it demonstrates properties similar to a crystalline ceramic. Vycor is 96% fused silica glass, which is crystal clear, lightweight and high strength. One advantage of these type of materials is that they can be produced in large sheets and other curved shapes.

Nanomaterials
It has been shown fairly recently that laser elements (amplifiers, switches, ion hosts, etc.) made from fine-grained ceramic nanomaterials—produced by the low temperature sintering of high purity nanoparticles and powders—can be produced at a relatively low cost. These components are free of internal stress or intrinsic birefringence, and allow relatively large doping levels or optimized custom-designed doping profiles. This highlights the use of ceramic nanomaterials as being particularly important for high-energy laser elements and applications.

Primary scattering centers in polycrystalline nanomaterials—made from the sintering of high purity nanoparticles and powders—include microstructural defects such as residual porosity and grain boundaries (see Transparent materials). Thus, opacity partly results from the incoherent scattering of light at internal surfaces and interfaces. In addition to porosity, most of the interfaces or internal surfaces in ceramic nanomaterials are in the form of grain boundaries which separate nanoscale regions of crystalline order. Moreover, when the size of the scattering center (or grain boundary) is reduced well below the size of the wavelength of the light being scattered, the light scattering no longer occurs to any significant extent.

In the processing of high performance ceramic nanomaterials with superior opto-mechanical properties under adverse conditions, the size of the crystalline grains is determined largely by the size of the crystalline particles present in the raw material during the synthesis or formation of the object. Thus a reduction of the original particle size well below the wavelength of visible light (~ 0.5 μm or 500 nm) eliminates much of the light scattering, resulting in a translucent or even transparent material.

Furthermore, results indicate that microscopic pores in sintered ceramic nanomaterials, mainly trapped at the junctions of microcrystalline grains, cause light to scatter and prevented true transparency. It has been observed that the total volume fraction of these nanoscale pores (both intergranular and intragranular porosity) must be less than 1% for high-quality optical transmission, i.e. the density has to be 99.99% of the theoretical crystalline density.

Nd:YAG
For example, a 1.46 kW Nd:YAG laser has been demonstrated by Konoshima Chemical Co. in Japan. In addition, Livermore researchers realized that these fine-grained ceramic nanomaterials might greatly benefit high-powered lasers used in the National Ignition Facility (NIF) Programs Directorate. In particular, a Livermore research team began to acquire advanced transparent nanomaterials from Konoshima to determine if they could meet the optical requirements needed for Livermore's Solid-State Heat Capacity Laser (SSHCL). Livermore researchers have also been testing applications of these materials for applications such as advanced drivers for laser-driven fusion power plants.

Assisted by several workers from the NIF, the Livermore team has produced 15 mm diameter samples of transparent Nd:YAG from nanoscale particles and powders, and determined the most important parameters affecting their quality. In these objects, the team largely followed the Japanese production and processing methodologies, and used an in house furnace to vacuum sinter the nanopowders. All specimens were then sent out for hot isostatic pressing (HIP). Finally, the components were returned to Livermore for coating and testing, with results indicating exceptional optical quality and properties.

One Japanese/East Indian consortium has focused specifically on the spectroscopic and stimulated emission characteristics of Nd3+ in transparent YAG nanomaterials for laser applications. Their materials were synthesized using vacuum sintering techniques. The spectroscopic studies suggest overall improvement in absorption and emission and reduction in scattering loss. Scanning electron microscope and transmission electron microscope observations revealed an excellent optical quality with low pore volume and narrow grain boundary width. Fluorescence and Raman measurements reveal that the Nd3+ doped YAG nanomaterial is comparable in quality to its single-crystal counterpart in both its radiative and non-radiative properties. Individual Stark levels are obtained from the absorption and fluorescence spectra and are analyzed in order to identify the stimulated emission channels possible in the material. Laser performance studies favor the use of high dopant concentration in the design of an efficient microchip laser. With 4 at% dopant, the group obtained a slope efficiency of 40%. High-power laser experiments yield an optical-to-optical conversion efficiency of 30% for Nd (0.6 at%) YAG nanomaterial as compared to 34% for an Nd (0.6 at%) YAG single crystal. Optical gain measurements conducted in these materials also show values comparable to single crystal, supporting the contention that these materials could be suitable substitutes to single crystals in solid-state laser applications.

Yttria, Y2O3
The initial work in developing transparent yttrium oxide nanomaterials was carried out by General Electric in the 1960s.

In 1966, a transparent ceramic, Yttralox, was invented by Dr. Richard C. Anderson at the General Electric Research Laboratory, with further work at GE's Metallurgy and Ceramics Laboratory by Drs. Paul J. Jorgensen, Joseph H. Rosolowski, and Douglas St. Pierre. Yttralox is "transparent as glass", has a melting point twice as high, and transmits frequencies in the near infrared band as well as visible light. Further development of yttrium ceramic nanomaterials was carried out by General Electric in the 1970s in Schenectady and Cleveland, motivated by lighting and ceramic laser applications. Yttralox, transparent yttrium oxide Y2O3 containing ~ 10% thorium oxide (ThO2) was fabricated by Greskovich and Woods. The additive served to control grain growth during densification, so that porosity remained on grain boundaries and not trapped inside grains where it would be quite difficult to eliminate during the initial stages of sintering. Typically, as polycrystalline ceramics densify during heat treatment, grains grow in size while the remaining porosity decreases both in volume fraction and in size. Optically transparent ceramics must be virtually pore-free.

GE's transparent Yttralox was followed by GTE's lanthana-doped yttria with similar level of additive. Both of these materials required extended firing times at temperatures above 2000 °C. La2O3 – doped Y2O3 is of interest for infrared (IR) applications because it is one of the longest wavelength transmitting oxides. It is refractory with a melting point of 2430 °C and has a moderate coefficient of thermal expansion. The thermal shock and erosion resistance is considered to be intermediate among the oxides, but outstanding compared to non-oxide IR transmitting materials. A major consideration is the low emissivity of yttria, which limits background radiation upon heating. It is also known that the phonon edge gradually moves to shorter wavelengths as a material is heated.

In addition, yttria itself, Y2O3 has been clearly identified as a prospective solid-state laser material. In particular, lasers with ytterbium as dopant allow the efficient operation both in cw operation and in pulsed regimes.

At high concentration of excitations (of order of 1%) and poor cooling, the quenching of emission at laser frequency and avalanche broadband emission takes place.

Future
The Livermore team is also exploring new ways to chemically synthesize the initial nanopowders. Borrowing on expertise developed in CMS over the past 5 years, the team is synthesizing nanopowders based on sol–gel processing, and then sintering them accordingly in order to obtain the solid-state laser components. Another technique being tested utilizes a combustion process in order to generate the powders by burning an organic solid containing yttrium, aluminum, and neodymium. The smoke is then collected, which consists of spherical nanoparticles.

The Livermore team is also exploring new forming techniques (e.g. extrusion molding) which have the capacity to create more diverse, and possibly more complicated, shapes. These include shells and tubes for improved coupling to the pump light and for more efficient heat transfer. In addition, different materials can be co-extruded and then sintered into a monolithic transparent solid. An amplifier slab can be formed so that part of the structure acts in guided lightwave transmission in order to focus pump light from laser diodes into regions with a high concentration of dopant ions near the slab center.

In general, nanomaterials promise to greatly expand the availability of low-cost, high-end laser components in much larger sizes than would be possible with traditional single crystalline ceramics. Many classes of laser designs could benefit from nanomaterial-based laser structures such as amplifies with built-in edge claddings. Nanomaterials could also provide more robust and compact designs for high-peak power, fusion-class lasers for stockpile stewardship, as well as high-average-power lasers for global theater ICBM missile defense systems (e.g. Strategic Defense Initiative SDI, or more recently the Missile Defense Agency.

Night vision

A night vision device (NVD) is an optical instrument that allows images to be produced in levels of light approaching total darkness. They are most often used by the military and law enforcement agencies, but are available to civilian users. Night vision devices were first used in World War II, and came into wide use during the Vietnam War. The technology has evolved greatly since their introduction, leading to several "generations" of night vision equipment with performance increasing and price decreasing. The United States Air Force is experimenting with Panoramic Night Vision Goggles (PNVGs) which double the user's field of view to approximately 95 degrees by using four 16 mm image intensifiers tubes, rather than the more standard two 18 mm tubes.

Thermal images are visual displays of the amount of infrared (IR) energy emitted, transmitted, and reflected by an object. Because there are multiple sources of the infrared energy, it is difficult to get an accurate temperature of an object using this method. A thermal imaging camera is capable of performing algorithms to interpret that data and build an image. Although the image shows the viewer an approximation of the temperature at which the object is operating, the camera is using multiple sources of data based on the areas surrounding the object to determine that value rather than detecting the temperature.

Night vision infrared devices image in the near-infrared, just beyond the visual spectrum, and can see emitted or reflected near-infrared in complete visual darkness. All objects above the absolute zero temperature (0 K) emit infrared radiation. Hence, an excellent way to measure thermal variations is to use an infrared vision device, usually a focal plane array (FPA) infrared camera capable of detecting radiation in the mid (3 to 5 μm) and long (7 to 14 μm) wave infrared bands, denoted as MWIR and LWIR, corresponding to two of the high transmittance infrared windows. Abnormal temperature profiles at the surface of an object are an indication of a potential problem. Infrared thermography, thermal imaging, and thermal video, are examples of infrared imaging science. Thermal imaging cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 900–14,000 nanometers or 0.9–14 μm) and produce images of that radiation, called thermograms.

Since infrared radiation is emitted by all objects near room temperature, according to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature. Therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become easily visible against the environment, day or night. As a result, thermography is particularly useful to the military and to security services.

Thermography
In thermographic imaging, infrared radiation with wavelengths between 8–13 micrometers strikes the detector material, heating it, and thus changing its electrical resistance. This resistance change is measured and processed into temperatures which can be used to create an image. Unlike other types of infrared detecting equipment, microbolometers utilizing a transparent ceramic detector do not require cooling. Thus, a microbolometer is essentially an uncooled thermal sensor.

The material used in the detector must demonstrate large changes in resistance as a result of minute changes in temperature. As the material is heated, due to the incoming infrared radiation, the resistance of the material decreases. This is related to the material's temperature coefficient of resistance (TCR) specifically its negative temperature coefficient. Industry currently manufactures microbolometers that contain materials with TCRs near −2%.

VO2 and V2O5
The most commonly used ceramic material in IR radiation microbolometers is vanadium oxide. The various crystalline forms of vanadium oxide include both VO2 and V2O5. Deposition at high temperatures and performing post-annealing allows for the production of thin films of these crystalline compounds with superior properties, which may be easily integrated into the fabrication process. VO2 has low resistance but undergoes a metal-insulator phase change near 67 °C and also has a lower TCR value. On the other hand, V2O5 exhibits high resistance and also high TCR.

Other IR transparent ceramic materials that have been investigated include doped forms of CuO, MnO and SiO.

Missiles
Many ceramic nanomaterials of interest for transparent armor solutions are also used for electromagnetic (EM) windows. These applications include radomes, IR domes, sensor protection, and multi-spectral windows. Optical properties of the materials used for these applications are critical, as the transmission window and related cut-offs (UV – IR) control the spectral bandwidth over which the window is operational. Not only must these materials possess abrasion resistance and strength properties common of most armor applications, but due to the extreme temperatures associated with the environment of military aircraft and missiles, they must also possess excellent thermal stability.

Thermal radiation is electromagnetic radiation emitted from the surface of an object which is due to the object's temperature. Infrared homing refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles that use infrared seeking are often referred to as "heat-seekers", since infrared is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and retain heat, and as such, are especially visible in the infrared wavelengths of light compared to objects in the background.

Sapphire
The current material of choice for high-speed infrared-guided missile domes is single-crystal sapphire. The optical transmission of sapphire does not extend to cover the entire mid-infrared range (3–5 μm), but starts to drop off at wavelengths greater than approximately 4.5 μm at room temperature. While the strength of sapphire is better than that of other available mid-range infrared dome materials at room temperature, it weakens above ~600 °C.

Limitations to larger area sapphires are often business related, in that larger induction furnaces and costly tooling dies are necessary in order to exceed current fabrication limits. However, as an industry, sapphire producers have remained competitive in the face of coating-hardened glass and new ceramic nanomaterials, and still managed to offer high performance and an expanded market.

Yttria, Y2O3
Alternative materials, such as yttrium oxide, offer better optical performance, but inferior mechanical durability. Future high-speed infrared-guided missiles will require new domes that are substantially more durable than those in use today, while still retaining maximum transparency across a wide wavelength range. A long-standing trade-off exists between optical bandpass and mechanical durability within the current collection of single-phase infrared transmitting materials, forcing missile designers to compromise on system performance. Optical nanocomposites may present the opportunity to engineer new materials that overcome this traditional compromise.

The first full scale missile domes of transparent yttria manufactured from nanoscale ceramic powders were developed in the 1980s under Navy funding. Raytheon perfected and characterized its undoped polycrystalline yttria, while lanthana-doped yttria was similarly developed by GTE Labs. The two versions had comparable IR transmittance, fracture toughness, and thermal expansion, while the undoped version exhibited twice the value of thermal conductivity.

Renewed interest in yttria windows and domes has prompted efforts to enhance mechanical properties by using nanoscale materials with submicrometer or nanosized grains. In one study, three vendors were selected to provide nanoscale powders for testing and evaluation, and they were compared to a conventional (5 μm) yttria powder previously used to prepare transparent yttria. While all of the nanopowders evaluated had impurity levels that were too high to allow processing to full transparency, 2 of them were processed to theoretical density and moderate transparency. Samples were sintered to a closed pore state at temperatures as low as 1400 C.

After the relatively short sintering period, the component is placed in a hot isostatic press (HIP) and processed for 3 – 10 hours at ~ 30 kpsi(~200 MPa) at a temperature similar to that of the initial sintering. The applied isostatic pressure provides additional driving force for densification by substantially increasing the atomic diffusion coefficients, which promotes additional viscous flow at or near grain boundaries and intergranular pores. Using this method, transparent yttria nanomaterials were produced at lower temperatures, shorter total firing times, and without extra additives which tend to reduce the thermal conductivity.

Recently, a newer method has been developed by Mouzon, which relies on the methods of glass-encapsulation, combined with vacuum sintering at 1600 °C followed by hot isostatic pressing (HIP) at 1500 °C of a highly agglomerated commercial powder. The use of evacuated glass capsules to perform HIP treatment allowed samples that showed open porosity after vacuum sintering to be sintered to transparency. The sintering response of the investigated powder was studied by careful microstructural observations using scanning electron microscopy and optical microscopy both in reflection and transmission. The key to this method is to keep porosity intergranular during pre-sintering, so that it can be removed subsequently by HIP treatment. It was found that agglomerates of closely packed particles are helpful to reach that purpose, since they densify fully and leave only intergranular porosity.

Composites
Prior to the work done at Raytheon, optical properties in nanocomposite ceramic materials had received little attention. Their studies clearly demonstrated near theoretical transmission in nanocomposite optical ceramics for the first time. The yttria/magnesia binary system is an ideal model system for nanocomposite formation. There is limited solid solubility in either one of the constituent phases, permitting a wide range of compositions to be investigated and compared to each other. According to the phase diagram, bi-phase mixtures are stable for all temperatures below ~ 2100 °C. In addition, neither yttria nor magnesia shows any absorption in the 3 – 5 μm mid-range IR portion of the EM spectrum.

In optical nanocomposites, two or more interpenetrating phases are mixed in a sub-micrometer grain sized, fully dense body. Infrared light scattering can be minimized (or even eliminated) in the material as long as the grain size of the individual phases is significantly smaller than infrared wavelengths. Experimental data suggests that limiting the grain size of the nanocomposite to approximately 1/15th of the wavelength of light is sufficient to limit scattering.

Nanocomposites of yttria and magnesia have been produced with a grain size of approximately 200 nm. These materials have yielded good transmission in the 3–5 μm range and strengths higher than that for single-phase individual constituents. Enhancement of mechanical properties in nanocomposite ceramic materials has been extensively studied. Significant increases in strength (2–5 times), toughness (1–4 times), and creep resistance have been observed in systems including SiC/Al2O3, SiC/Si3N4, SiC/MgO, and Al2O3/ZrO2.

The strengthening mechanisms observed vary depending on the material system, and there does not appear to be any general consensus regarding strengthening mechanisms, even within a given system. In the SiC/Al2O3 system, for example, it is widely known and accepted that the addition of SiC particles to the Al2O3 matrix results in a change of failure mechanism from intergranular (between grains) to intragranular (within grains) fracture. The explanations for improved strength include:

 * A simple reduction of processing flaw concentration during nanocomposite fabrication.
 * Reduction of the critical flaw size in the material—resulting in increased strength as predicted by the Hall-Petch relation)
 * Crack deflection at nanophase particles due to residual thermal stresses introduced upon cooling form processing temperatures.
 * Microcracking along stress-induced dislocations in the matrix material.

Armor
There is an increasing need in the military sector for high-strength, robust materials which have the capability to transmit light around the visible (0.4–0.7 micrometers) and mid-infrared (1–5 micrometers) regions of the spectrum. These materials are needed for applications requiring transparent armor. Transparent armor is a material or system of materials designed to be optically transparent, yet protect from fragmentation or ballistic impacts. The primary requirement for a transparent armor system is to not only defeat the designated threat but also provide a multi-hit capability with minimized distortion of surrounding areas. Transparent armor windows must also be compatible with night vision equipment. New materials that are thinner, lightweight, and offer better ballistic performance are being sought.

Existing transparent armor systems typically have many layers, separated by polymer (e.g. polycarbonate) interlayers. The polymer interlayer is used to mitigate the stresses from thermal expansion mismatches, as well as to stop crack propagation from ceramic to polymer. The polycarbonate is also currently used in applications such as visors, face shields and laser protection goggles. The search for lighter materials has also led to investigations into other polymeric materials such as transparent nylons, polyurethane, and acrylics. The optical properties and durability of transparent plastics limit their use in armor applications. Investigations carried out in the 1970s had shown promise for the use of polyurethane as armor material, but the optical properties were not adequate for transparent armor applications.

Several glasses are utilized in transparent armor, such as normal plate glass (soda-lime-silica), borosilicate glasses, and fused silica. Plate glass has been the most common glass used due to its low cost, but greater requirements for the optical properties and ballistic performance have generated the need for new materials. Chemical or thermal treatments can increase the strength of glasses, and the controlled crystallization of certain glass systems can produce transparent glass-ceramics. Alstom Grid Research & Technology (Stafford, UK), produced a lithium disilicate based glass-ceramic known as TransArm, for use in transparent armor systems with continuous production yielding vehicle windscreen sized pieces (and larger). The inherent advantages of glasses and glass-ceramics include having lower cost than most other ceramic materials, the ability to be produced in curved shapes, and the ability to be formed into large sheets.

Transparent crystalline ceramics are used to defeat advanced threats. Three major transparent candidates currently exist: aluminum oxynitride (AlON), magnesium aluminate spinel (spinel), and single crystal aluminum oxide (sapphire).

Aluminium oxynitride spinel
Aluminium oxynitride spinel (Al23O27N5), abbreviated as AlON, is one of the leading candidates for transparent armor. It is produced by the Surmet Corporation under the trademark ALON. The incorporation of nitrogen into aluminium oxide stabilizes a crystalline spinel phase, which due to its cubic crystal structure and unit cell, is an isotropic material which can be produced as transparent ceramic nanomaterial. Thus, fine-grained polycrystalline nanomaterials can be produced and formed into complex geometries using conventional ceramic forming techniques such as hot isostatic pressing, and slip casting.

The Surmet Corporation has acquired Raytheon's ALON business and is currently building a market for this technology in the area of Transparent Armor, Sensor windows, Reconnaissance windows and IR Optics such as Lenses and Domes and as an alternative to quartz and sapphire in the semiconductor market. The AlON based transparent armor has been tested to stop multi-hit threats including of 30calAPM2 rounds and 50calAPM2 rounds successfully. The high hardness of AlON provides a scratch resistance which exceeds even the most durable coatings for glass scanner windows, such as those used in supermarkets. Surmet has successfully produced a 15"x18" curved AlON window and is currently attempting to scale up the technology and reduce the cost. In addition, the U.S. Army and U.S. Air Force are both seeking development into next generation applications.

Spinel
Magnesium aluminate spinel (MgAl2O4) is a transparent ceramic with a cubic crystal structure with an excellent optical transmission from 0.2 to 5.5 micrometers in its polycrystalline form. Optical quality transparent spinel has been produced by sinter/HIP, hot pressing, and hot press/HIP operations, and it has been shown that the use of a hot isostatic press can improve its optical and physical properties.

Spinel offers some processing advantages over AlON, such as the fact that spinel powder is available from commercial manufacturers while AlON powders are proprietary to Raytheon. It is also capable of being processed at much lower temperatures than AlON and has been shown to possess superior optical properties within the infrared (IR) region. The improved optical characteristics make spinel attractive in sensor applications where effective communication is impacted by the protective missile dome's absorption characteristics.

Spinel shows promise for many applications, but is currently not available in bulk form from any manufacturer, although efforts to commercialize spinel are underway. The spinel products business is being pursued by two key U.S. manufacturers: "Technology Assessment and Transfer" and the "Surmet Corporation".

An extensive NRL review of the literature has indicated clearly that attempts to make high-quality spinel have failed to date because the densification dynamics of spinel are poorly understood. They have conducted extensive research into the dynamics involved during the densification of spinel. Their research has shown that LiF, although necessary, also has extremely adverse effects during the final stages of densification. Additionally, its distribution in the precursor spinel powders is of critical importance.

Traditional bulk mixing processes used to mix LiF sintering aid into a powder leave fairly inhomogeneous distribution of Lif that must be homogenized by extended heat treatment times at elevated temperatures. The homogenizing temperature for Lif/Spinel occurs at the temperature of fast reaction between the LiF and the Al2O3. In order to avoid this detrimental reaction, they have developed a new process that uniformly coats the spinel particles with the sintering aid. This allows them to reduce the amount of Lif necessary for densification and to rapidly heat through the temperature of maximum reactivity. These developments have allowed NRL to fabricate MgAl2O4 spinel to high transparency with extremely high reproducibility that should enable military as well as commercial use of spinel.

Sapphire
Single-crystal aluminum oxide (sapphire – Al2O3) is a transparent ceramic. Sapphire's crystal structure is rhombohedral and thus its properties are anisotropic, varying with crystallographic orientation. Transparent alumina is currently one of the most mature transparent ceramics from a production and application perspective, and is available from several manufacturers. But the cost is high due to the processing temperature involved, as well as machining costs to cut parts out of single crystal boules. It also has a very high mechanical strength – but that is dependent on the surface finish.

The high level of maturity of sapphire from a production and application standpoint can be attributed to two areas of business: electromagnetic spectrum windows for missiles and domes, and electronic/semiconductor industries and applications.

There are current programs to scale-up sapphire grown by the heat exchanger method or edge defined film-fed growth (EFG) processes. Its maturity stems from its use as windows and in semiconductor industry. Crystal Systems Inc. which uses single crystal growth techniques, is currently scaling their sapphire boules to 13 in diameter and larger. Another producer, the Saint-Gobain Group produces transparent sapphire using an edge-defined growth technique. Sapphire grown by this technique produces an optically inferior material to that which is grown via single crystal techniques, but is much less expensive, and retains much of the hardness, transmission, and scratch-resistant characteristics. Saint-Gobain is currently capable of producing 0.43" thick (as grown) sapphire, in 12" × 18.5" sheets, as well as thick, single-curved sheets. The U.S. Army Research Laboratory is currently investigating use of this material in a laminate design for transparent armor systems. The Saint Gobain Group have commercialized the capability to meet flight requirements on the F-35 Joint Strike Fighter and F-22 Raptor next generation fighter aircraft.

Composites
Future high-speed infrared-guided missiles will require new dome materials that are substantially more durable than those in use today, while retaining maximum transparency across the entire operational spectrum or bandwidth. A long-standing compromise exists between optical bandpass and mechanical durability within the current group of single-phase (crystalline or glassy) IR transmitting ceramic materials, forcing missile designers to accept substandard overall system performance. Optical nanocomposites may provide the opportunity to engineer new materials that may overcome these traditional limitations.

For example, transparent ceramic armor consisting of a lightweight composite has been formed by utilizing a face plate of transparent alumina Al2O3 (or magnesia MgO) with a back-up plate of transparent plastic. The two plates (bonded together with a transparent adhesive) afford complete ballistic protection against 0.30 AP M2 projectiles at 0° obliquity with a muzzle velocity of 2770 ft per second. Another transparent composite armor provided complete protection for small arms projectiles up to and including caliber .50 AP M2 projectiles consisting of two or more layers of transparent ceramic material.

Nanocomposites of yttria and magnesia have been produced with an average grain size of ~200 nm. These materials have exhibited near theoretical transmission in the 3 – 5 μm IR band. Additionally, such composites have yielded higher strengths than those observed for single phase solid-state components. Despite a lack of agreement regarding mechanism of failure, it is widely accepted that nanocomposite ceramic materials can and do offer improved mechanical properties over those of single phase materials or nanomaterials of uniform chemical composition.

Nanocomposite ceramic materials also offer interesting mechanical properties not achievable in other materials, such as superplastic flow and metal-like machinability. It is anticipated that further development will result in high strength, high transparency nanomaterials which are suitable for application as next generation armor.

title: Transparent ceramics


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Talk:Edwin Flack

Untitled
Edwin Flack is also honoured by having an Edwin Flack Ave at Sydney Olympic Park named after him.--203.217.45.241 06:47, 26 January 2007 (UTC)

(1) A radio documentary on ABC Radio National in Australia (Hindsight 15AUG04 and audio for a few weeks) gives the sequence as: 800m, 1500m, tennis, marathon. I will amend this sequence on the page if there is no objection within a few days.

(2) Nothing much is brought out about the common fallacy of Flack not being "Australia's first gold medalist". Gold medals were brought in at a later games (1904??). The first medals were silver (1st) and bronze (2nd) and nothing (3rd), and the current medals are 'gilt' (gold over silver), which is discussed on the main Olympics page.

Peter Ellis 01:42, 17 Aug 2004 (UTC)

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Category:Activism

Activism consists of efforts to promote, impede, or direct social, political, economic, or environmental change, or stasis. The term connotes a peaceful form of conflict.

title: Category:Activism