title: Juan Sebastián Elcano

text: Nor did the book, "Relazione del primo viaggio intorno al mondo", by Antonio Pigafetta, the Venetian scholar who sailed with Magellan and who was among the 18 men that survived the expedition and returned to Spain, mention Elcano. In its received form, his chronicle exaggerates his own role, perhaps explaining why in Italian historiography Elcano disappears and "Capitano Pigafetta" himself appears as an important character.


title: Juan Sebastián Elcano

text: In recent years, however, another point of view has spread: Pigafetta quoted Elcano, but as the works of Pigafetta that have survived to modern times were modified in transmission, perhaps mentions of Elcano were suppressed. The original Pigafetta chronicle is lost, and the account in its present form would be a retranslation of a translation made in France, written later, and suppressing or modifying many sections. The hypothesis is that, since France was at war with Castile, the French eliminated all the "Spaniards" that Pigafetta had praised in his telling of the voyage. This 'eliminatory' view was further extended when it was written by Philip II's chronicler, embellishing the roles of the hidalgos Magellan and Pigafetta and minimising that of the plebeians. Spanish historiography transformed Magellan into a leader who favored the unity of Portugal and Spain, although he had betrayed Portugal by becoming Castilian. Thus, he became a hero for the Castilians whose political position was consequently enhanced.


title: Juan Sebastián Elcano

text: It was in the interest of Castile to elevate Magellan, and to push Elcano aside, but also of the Catholic Church. The tug of war between the empire of Charles V and the Roman Catholic Church was constant. The Holy Roman Empire presented itself as a Catholic Empire, but at the same time it did not control the center of religion, that is, Rome. The Church did not want Charles V to have too much power. Therefore, the Church wanted to mark a contrast between the bloody evangelisation that Spain carried out in the Americas and the supposedly peaceful evangelisation that Portugal carried out in Asia. Since it was convenient for it to emphasize that Spain's attempt at evangelisation had been drenched with blood, while Portugal's was a builder of civilization, the Church found it advantageous to praise Magellan. Thus, Magellan was praised by Rome and England, who were allied with Portugal against Spain. Magellan was taken as a model of civilization, and Francis Drake as the executor of his dream.


title: Juan Sebastián Elcano

text: Although many technical and economic documents have survived, most of the originals have disappeared; their existence is known because these documents are cited by those who received the records of the times. Neither the actual text of the chronicle of Elcano's voyage, records of the proceedings of the trial of Carvalho, the documentation provided by Elcano at the Badajoz-Elvas meetings, nor the ship's logbook have been found. The Trinidad ship's book has also been lost, although it was taken by Portugal. Historian Enrique Santamaría believes these documents have been destroyed, probably in the 19th century; he finds it difficult to credit that they were lost, they being of immense historical value, and observes that documents with many other details of the voyage have survived.


title: Juan Sebastián Elcano

text: In the context of the Napoleonic Wars, feelings of nationalism arose in most European countries. In Spain this sentiment had a conservative component supported by the monarchy, that in its retrospective view, held that the Spanish people needed to construct a new national historiography; this task fell to Martín Fernández de Navarrete, director of the Royal Academy of History. In 1825 Fernández de Navarrete wrote a modern 'official' account of the first circumnavigation of the earth, "Colección de los viajes y descubrimientos que hicieron por mar los españoles", in which Magellan is praised, and the figure of Elcano passed down by tradition was remade.


title: Juan Sebastián Elcano

text: At a time when Spain was experiencing the decolonization of America, the Spanish government desired to present a national historical narrative that legitimized the power of the ruling elites, a message that inevitably would diminish the position of the lower classes. In Navarrete's telling Magellan became an exemplar of those elevated persons who must struggle against the incapacity of common men to understand the complexities of governance, portraying him as of noble character, an upholder of the Christian faith, and a leader in the advancement of civilization. In contrast to these virtuous qualities he attributed to Magellan, Elcano was a man in the habit of deciding important matters democratically by vote, one who had never conquered another race of people that could be evangelized and civilized, nor had he ever even tried. Thus, in Navarrete's account, crediting Elcano with the completion of the first circumnavigation is understood as an injustice to the memory of Magellan's achievements, and Navarette's history is an attempt to rectify this error. The historical conception of a Spanish nation as presented by Navarrete has subsequently been propagated by historians of other nationalities, and remained a dominant view internationally for many years.


title: Juan Sebastián Elcano

text: In 1861 the soldier Juan Cotarelo Garastazu, a field marshal ("mariscal de campo") of the Spanish army, wrote the first biography of Elcano. He writes that Elcano was "humble and obedient" and that he had managed to sail around the world in obedience to his king, submitting as proof that in the rigorous Valladolid inquiry concerning the circumnavigation, Elcano responded in a humble, modest way to the thirteen question he was asked.


title: Juan Sebastián Elcano

text: Eustaquio Fernández de Navarrete, grandson of Martín Fernández de Navarrete, wrote a more complete biography of Elcano in 1872. This biography has a more neutral, analytical approach to its subject and has been the main reference for historians. As it was problematic for some people that Elcano lacked a noble pedigree, in order to vindicate his reputation, Eustaquio Fernández de Navarrete suggested, without providing any proof, that Elcano had taken part in the Siege of Oran and in the Italian wars.


title: Juan Sebastián Elcano

text: Elcano was a posthumous victim of political machinations in the 19th century when Antonio Cánovas del Castillo faced the creation of peripheral Basque nationalist movements and "fuerismo" concerning the laws (fueros) of the different provinces of the Basque region; this occurred in a chaotic scenario after the overthrow of the First Spanish Republic. The so-called foral laws set up a legal framework in which authority was shared between the monarchy, whose agencies governed local affairs of interest to the Crown, and provincial institutions, which managed their own affairs concerning local traditions and customs. Cánovas believed that the foralists used a distorted history to defend their politics and, for this reason he wanted to minimize the role of the Basques and the Navarrese in Iberian history. Thus, he tried to disappear not only Elcano, but also Blas de Lezo, Churruca, Andrés de Urdaneta, and Legazpi from this history, establishing a damnatio memoriae. To eradicate Elcano's place as a heroic figure, Cánovas reinforced the use of the Portuguese Magellan as a symbol of the political unity of the Iberian Peninsula, averring that Elcano was no more than the "humble master" ("modesto maestre") of the ship "Victoria" that completed the first circumnavigation of the Earth.


title: Juan Sebastián Elcano

text: Prime Minister of Spain Primo de Rivera, however, wanted to restore Elcano's reputation and named a training ship of the Spanish Navy, "Juan Sebastián de Elcano]]" (A-71), after him. Franco's regime tried to make Elcano a national mythical figure, using the narrative written by Eustaquio Fernández de Navarrete (1872).


title: Juan Sebastián Elcano

text: Amado Melón Ruiz de Gordejuela in his book "Magallanes o la Primera Vuelta al Mundo", published in 1940 in the collection "La España Imperial", affirmed that Elcano participated in the siege of Oran and was an assistant to "The Great Captain", Gonzalo Fernandez de Cordova, who campaigned in Italy between 1495 and 1504. Melón Ruiz wanted to place Elcano in Oran, and added 10 years to his age (otherwise he would have been only 8 years old), and promulgated the fiction that Elcano was born in 1476 rather than 1487. With the acceptance of this fabricated birth date by historians, the false information that Elcano participated in the Oran campaign has been widely published in history books.


title: Juan Sebastián Elcano

text: The 500th anniversary of the first circumnavigation was celebrated in Spain on September 6, 2022. In view of this, several initiatives such as the Elkano Foundation have arisen, both to complete the history and perpetuate its memory and to plan the celebration of the event.


title: Juan Sebastián Elcano

text: As part of the commemoration of the 500th anniversary of the first circumnavigation of the Earth on September 6, 1522, the Basque Maritime Museum, with the support of the Elkano Foundation, has published a new book: "Elcano y el País Vasco. Cómo se hizo posible la primera vuelta al mundo" (June 2022).


title: Juan Sebastián Elcano

text: There is no description or contemporary artwork depicting Elcano, and all artworks depicting him were made centuries later, often with ahistorical elements in their composition and featuring anachronistic clothing.


title: Juan Sebastián Elcano

text: In 2019 an animated movie was made in the Basque language by Ángel Alonso with the title "Elkano, lehen mundu bira". In 2020 another animation movie by Manuel H. Martin called "El viaje más largo" was presented in Sevilla. In 2022 Amazon Prime broadcast the series "Boundless", with Álvaro Morte as Elcano.


title: Jerry Rawlings

text: Jerry John Rawlings (22 June 194712 November 2020) was a Ghanaian military officer and politician who led the country for a brief period in 1979, and then from 1981 to 2001. He led a military junta until 1992, and then served two terms as the democratically elected President of Ghana.


title: Jerry Rawlings

text: Rawlings came to power in Ghana as a flight lieutenant of the Ghana Air Force following a coup d'état in 1979. Prior to that, he led an unsuccessful coup attempt against the ruling military government on 15 May 1979, just five weeks before scheduled democratic elections were due to take place. After handing power over to a civilian government, he took back control of the country on 31 December 1981 as the chairman of the Provisional National Defence Council (PNDC).


title: Jerry Rawlings

text: In 1992, Rawlings resigned from the military, founded the National Democratic Congress (NDC), and became the first President of the Fourth Republic. He was re-elected in 1996 for four more years. After two terms in office, the limit according to the Ghanaian Constitution, Rawlings endorsed his vice-president John Atta Mills as a presidential candidate in 2000. Rawlings served as the African Union envoy to Somalia. He died in November 2020, at age 73 and was accorded a state funeral.


title: Jerry Rawlings

text: Rawlings was born as Jerry Rawlings John on 22 June 1947 in Accra, Ghana, to Victoria Agbotui, an Anlo Ewe from Dzelukope, Keta, and James Ramsey John, a British chemist from Castle Douglas in Kirkcudbrightshire, Scotland. Rawlings attended Achimota School and a military academy at Teshie. Rawlings was married to Nana Konadu Agyeman, whom he met while at Achimota College. They had three daughters: Zanetor Rawlings, Yaa Asantewaa Rawlings, Amina Rawlings; and one son, Kimathi Rawlings. Junior Agogo was the nephew of Rawlings.


title: Jerry Rawlings

text: Rawlings finished his secondary education at Achimota College in 1967. He joined the Ghana Air Force shortly afterwards; on his application, the military switched his surname John and his middle name Rawlings. In March 1968, he was posted to Takoradi, in Ghana's Western Region, to continue his studies. He graduated in January 1969, and was commissioned as a pilot officer, winning the coveted "Speed Bird Trophy" as the best cadet in flying the Su-7 ground attack supersonic jet aircraft as he was skilled in aerobatics. He earned the rank of flight lieutenant in April 1978. During his service with the Ghana Air Force, Rawlings perceived a deterioration in discipline and morale due to corruption in the Supreme Military Council (SMC). As promotion brought him into contact with the privileged classes and their social values, his view of the injustices in society hardened. He was thus regarded with some unease by the SMC. After the 1979 coup, he involved himself with the student community of the University of Ghana, where he developed a more leftist ideology through reading and discussion of social and political ideas.


title: Jerry Rawlings

text: Rawlings grew discontented with Ignatius Kutu Acheampong's government, which had come to power through a coup in January 1972. Acheampong was accused not only of corruption, but also of maintaining Ghana's dependency on pre-colonial powers, in a situation which led to economic decline and impoverishment.


title: Jerry Rawlings

text: Rawlings was part of the Free Africa Movement, an underground movement of military officers who wanted to unify Africa through a series of coups. On 15 May 1979, five weeks prior to civilian elections, Rawlings and six other soldiers staged a coup against the government of General Fred Akuffo, but failed and were arrested by the military. Rawlings was publicly sentenced to death in a General Court Martial and imprisoned, although his statements on the social injustices that motivated his actions won him civilian sympathy. While awaiting execution, Rawlings was sprung from custody on 4 June 1979 by a group of soldiers. Claiming that the government was corrupt beyond redemption and that new leadership was required for Ghana's development, he led the group in a coup to oust the Akuffo Government and Supreme Military Council. Shortly afterwards, Rawlings established and became the Chairman of a 15-member Armed Forces Revolutionary Council (AFRC), primarily composed of junior officers. He and the AFRC ruled for 112 days and arranged the execution by firing squad of eight military officers, including Generals Kotei, Joy Amedume, Roger Felli, and Utuka, as well as the three former Ghanaian heads of state; Acheampong, Akuffo, and Akwasi Afrifa.


title: Jerry Rawlings

text: These executions were dramatic events in the history of Ghana, which had previously suffered few instances of political violence. Rawlings later implemented a much wider "house-cleaning exercise" involving the killings and abduction of over 300 Ghanaians. Elections were held on time shortly after the coup. On 24 September 1979, power was peacefully handed over by Rawlings to President Hilla Limann, whose People's National Party (PNP) had the support of Nkrumah's followers. Two years later, on 31 December 1981 Rawlings ousted President Hilla Limann in a coup d'état, claiming that civilian rule was weak and the country's economy was deteriorating. The killings of the Supreme Court justices (Cecilia Koranteng-Addow, Frederick Sarkodie, and Kwadjo Agyei Agyepong), military officers Major Sam Acquah and Major Dasana Nantogmah also occurred during the second military rule of Rawlings. However, unlike the 1979 executions, these persons were abducted and killed in secret and it is unclear who was behind their murders, though Joachim Amartey Kwei and four others were convicted of murdering the Justices and Acquah, and were executed in 1982.


title: Jerry Rawlings

text: Believing the Limann regime to be unable to resolve Ghana's neocolonial economic dependency, Rawlings led a second coup against Limann and indicted the entire political class on 31 December 1981. In place of Limann's People's National Party, Rawlings established the Provisional National Defence Council (PNDC) military junta as the official government.


title: Jerry Rawlings

text: Rawlings hosted state visits from "revolutionaries" from other countries, including Dési Bouterse (Suriname), Daniel Ortega (Nicaragua), and Sam Nujoma (Namibia). More famously, Rawlings reversed Limann's boycott of Gaddafist Libya, allowing the Black Stars to compete in the 1982 African Cup of Nations. The team won the AFCON trophy for the fourth time, their last win as of 2022.


title: Jerry Rawlings

text: Although the PNDC claimed to be representative of the people, it lacked experience in the creation and implementation of clear economic policies. Rawlings, like many of his predecessors, attributed current economic and social problems to the "trade malpractices and other anti-social activities" of a few businesspeople. In December 1982, the PNDC announced its four-year economic program of establishing a state monopoly on export-import trade with the goal of eliminating corruption surrounding import licences and shift trade away from dependency on Western markets. Unrealistic price controls were imposed on the market and enforced through coercive acts, especially against businesspeople. This resolve to employ state control over the economy is best demonstrated by the destruction of the Makola No.1 Market. The PNDC established Workers' Defence Committees (WDCs) and People's Defence Committees (PDCs) to mobilize the population to support radical changes to the economy. Price controls on the sale of food were beneficial to urban workers, but placed undue burden on 70% of the rural population whose income largely depended on the prices of agricultural products. Rawlings' economic policies led to an economic crisis in 1983, forcing him to undertake structural adjustment and submit himself to election to retain power. Elections were held in January 1992, leading Ghana back to multiparty democracy.


title: Jerry Rawlings

text: Rawlings established the National Commission on Democracy (NCD) shortly after the 1982 coup, and employed it to survey civilian opinion and make recommendations that would facilitate the process of democratic transition. In March 1991, the NCD released a report recommending the election of an executive president, the establishment of a national assembly, and the creation of the post of prime minister. The PNDC used NCD recommendations to establish a committee for the drafting of a new constitution based on past Ghanaian Constitutions, that lifted the ban on political parties in May 1992 after it was approved by referendum.


title: Jerry Rawlings

text: On 3 November 1992, election results compiled by the INEC from 200 constituencies showed that Rawlings' NDC had won 60% of the votes, and had obtained the majority needed to prevent a second round of voting. More specifically, the NDC won 62% in the Brong-Ahafo region, 93% in the Volta region, and majority votes in Upper West, Upper East, Western, Northern, Central, and Greater Accra regions. His opponents Professor Adu Boahen won 31% of the votes, former President Hilla Limann won 6.8%, Kwabena Darko won 2.9%, and Emmanuel Erskine won 1.7%. Voter turnout was 50%.


title: Jerry Rawlings

text: The ability of opposition parties to compete was limited by the vast advantages Rawlings possessed. Rawlings' victory was aided by the various party structures that were integrated into society during his rule, called the "organs of the revolution". These structures included the Committees for the Defence of the Revolution (CDRs), Commando Units, 31 December Women's Organization, the 4 June movement, Peoples Militias, and Mobisquads, and operated on a system of popular control through intimidation. Rawlings held a monopoly over national media, and was able to censor print and electronic media through a PNDC newspaper licensing decree, PNDC Law 221. Moreover, Rawlings imposed a 20,000 cedis (about $400) cap on campaign contributions, which made national publicity of opposition parties virtually impossible. Rawlings himself began campaigning before the official unbanning of political parties and had access to state resources and was able to effectively meet all monetary demands required of a successful campaign. Rawlings travelled across the country, initiating public-works projects and giving public employees a 60% pay rise prior to election day.


title: Jerry Rawlings

text: Opposition parties objected to the election results, citing incidences of vote stuffing in regions where Rawlings was likely to lose and rural areas with scant populations, as well as a bloated voters' register and a partisan electoral commission. However, the Commonwealth Observer Group, led by Sir Ellis Clarke, approved of the election as "free and fair", as there were very few issues at polling stations and no major incidences of voter coercion. In contrast, the International Foundation for Electoral Systems (IFES) issued a report supporting claims that erroneous entries in voter registration could have affected election results. The Carter Center did acknowledge minor electoral issues but did not see these problems as indicative of systematic electoral fraud.


title: Jerry Rawlings

text: Opposition parties boycotted subsequent Ghana parliamentary and presidential elections, and the unicameral National Assembly, of which NDC officials won 189 of 200 seats and essentially established a one-party parliament that lacked legitimacy and only had limited legislative powers. After the disputed election, the PNDC was transformed into the National Democratic Congress (NDC).


title: Jerry Rawlings

text: Rawlings took office on 7 January 1993, the same day that the new constitution came into effect, and the government became known as the Fourth Republic of Ghana.


title: Jerry Rawlings

text: Rawlings established the Economic Recovery Program (ERP) suggested by the World Bank and the International Monetary Fund in 1982 due to the poor state of the economy after 18 months of attempting to govern it through administrative controls and mass mobilization. The policies implemented caused a dramatic currency devaluation, the removal of price controls, and social-service subsidies which favored farmers over urban workers, and privatization of some state-owned enterprises, and restraints on government spending. Funding was provided by bilateral donors, reaching US$800 million in 1987 and 1988, and US$900 million in 1989.


title: Jerry Rawlings

text: Between 1992 and 1996, Rawlings eased control over the judiciary and civil society, allowing a more independent Supreme Court and the publication of independent newspapers. Opposition parties operated outside of parliament and held rallies and press conferences.


title: Jerry Rawlings

text: Given the various issues with the 1992 elections, the 1996 elections were a great improvement in terms of electoral oversight. Voter registration was re-compiled, with close to 9.2 million voters registering at nearly 19,000 polling stations, which the opposition had largely approved after party agents had reviewed the lists. The emphasis on transparency led Ghanaian non-governmental organizations to create the Network of Domestic Election Observers (NEDEO), which trained nearly 4,100 local poll watchers. This organization was popular across political parties and civic groups. On the day of the election, more than 60,000 candidate agents monitored close to all polling sites, and were responsible for directly reporting results to their respective party leaders. The parallel vote-tabulation system allowed polling sites to compare their results to the official ones released by the Electoral commission. The Inter-Party Advisory Committee (IPAC) was established to discuss election preparations with all parties and the Electoral Commission, as well as establish procedures to investigate and resolve complaints. Presidential and parliamentary elections were held on the same day and see-through boxes were used in order to further ensure the legitimacy of the elections. Despite some fears of electoral violence, the election was peaceful and had a 78% turnout rate, and was successful with only minor problems such as an inadequate supply of ink and parliamentary ballots.


title: Jerry Rawlings

text: The two major contenders of the 1996 election were Rawlings' NDC, and John Kufuor's Great Alliance, an amalgamation of the New Patriotic Party (NPP) and the People's Convention Party (PCP). The Great Alliance based their platform on ousting Rawlings, and attacked the incumbent government for its poor fiscal policies. However, they were unable to articulate a clear positive message of their own, or plans to change the current economic policy. As Ghana was heavily dependent on international aid, local leaders had minimal impact on the economy. The Electoral Commission reported that Rawlings had won by 57%, with Kufuor obtaining 40% of the vote. Results by district were similar to those in 1992, with the opposition winning the Ashanti Region and some constituencies in Eastern and Greater Accra, and Rawlings winning in his ethnic home, the Volta Region, and faring well in every other region. The NDC took 134 seats in the Assembly compared to the opposition's 66, and the NPP took 60 seats in the parliament.


title: Jerry Rawlings

text: The 1992 constitution limits a president to two terms, even if they are nonconsecutive. Rawlings did not attempt to amend the document to allow him to run for a third term in 2000. He retired in 2001 and was succeeded by John Agyekum Kufuor, his main rival and opponent in 1996. It was the first time in Ghanaian history that a sitting government peacefully transferred power to an elected member of the opposition.


title: Jerry Rawlings

text: Kufuor won the presidency after defeating Rawlings' vice-president John Atta Mills in a runoff in 2000. In 2004, Mills conceded to Kufuor after another election between the two.


title: Jerry Rawlings

text: In November 2000, Rawlings was named the first International Year of Volunteers 2001 Eminent Person by UN Secretary-General Kofi Annan, attending various events and conferences to promote volunteerism.


title: Jerry Rawlings

text: In October 2010, Rawlings was named as the African Union envoy to Somalia. In November 2010, he attended the inauguration of Dési Bouterse as President of Suriname, and took a tour of the country. He was especially interested in the Ghanaian origins of the Maroon people.


title: Jerry Rawlings

text: Rawlings delivered lectures at universities, including Oxford University in England. Rawlings continued his heavy support for NDC. In July 2019, he went on a three-day working trip to Burkina Faso in the capacity of Chairman of the Thomas Sankara Memorial Committee.


title: Jerry Rawlings

text: In September 2019, he paid a tribute on behalf of the president and people of Ghana, when he led a delegation to the funeral of Robert Mugabe, the late former president of Zimbabwe.


title: Jerry Rawlings

text: Rawlings died on 12 November 2020 at Korle-Bu Teaching Hospital in Accra, a week after having been admitted for a "short term illness" in Ghana. According to some reports, his death was caused by complications from COVID-19. His death came nearly two months after that of his mother, Victoria Agbotui, on 24 September 2020. President Nana Akufo-Addo declared a seven-day period of mourning in his honor and flags flown at half-mast. His family members appealed to the Government of Ghana to bury him in Keta in the Volta Region. A schedule for the signing of a book of condolence was opened in his memory. His funeral, originally planned for 23 December 2020, was postponed at the request of his family.


title: Jerry Rawlings

text: From 24 to 27 January 2021, funeral ceremonies were organised at Accra in Rawlings' memory. A requiem mass for Jerry Rawlings was held at the Holy Spirit Cathedral on 24 January 2021, followed by a vigil at the Air Force Officers' Mess in Accra later that evening. His body was laid in state in the foyer of the Accra International Conference Centre from 25 to 26 January 2021. There were also traditional rites performed by the Anlo Ewe people of his maternal ancestry. On 27 January 2021, a state funeral, attended by national and international political leaders, paramount chiefs, diplomats and other dignitaries, was held at the Black Star Square before his burial service at the Military Cemetery at Burma Camp, with full military honours, including a slow march by the funeral cortège, a flypast of a Ghana Air Force helicopter, the sounding of the Last Post by army buglers and a 21-gun salute.


title: Jerry Rawlings

text: President Nana Akufo-Addo proposed to the Governing Council of UDS to rename the institution after Jerry John Rawlings since Rawlings used his US$50,000 Hunger Project prize as seed money to establish the university. This suggestion was accepted by his family.


title: Jerry Rawlings

text: The following are physical books relevant to Jerry Rawlings, which may not be available online, but are added in case of looking for more information.


title: Jerry Rawlings

text: See also, Shipley, Jesse Weaver. “Alternative Histories of Global Sovereignty: Ghana’s Lost Revolution” "Comparative Studies of South Asia, Africa and the Middle East". Vol. 42, No. 2, 2022, pp. 532-537. DOI 10.1215/1089201X09988009.


title: Classical Latin

text: Classical Latin is the form of Literary Latin recognized as a literary standard by writers of the late Roman Republic and early Roman Empire. It was used from 75 BC to the 3rd century AD, when it developed into Late Latin. In some later periods, it was regarded as good or proper Latin, with following versions viewed as debased, degenerate, or corrupted. The word "Latin" is now understood by default to mean "Classical Latin"; for example, modern Latin textbooks almost exclusively teach Classical Latin.


title: Classical Latin

text: Cicero and his contemporaries of the late republic referred to the Latin language, in contrast to other languages such as Greek, as or . They distinguished the common vernacular, however, as Vulgar Latin ("sermo vulgaris" and "sermo vulgi"), in contrast to the higher register that they called , sometimes translated as "Latinity". "Latinitas" was also called ("speech of the good families"), "sermo urbanus" ("speech of the city"), and in rare cases "sermo nobilis" ("noble speech"). Besides the noun "Latinitas", it was referred to with the adverb "latine" ("in (good) Latin", literally "Latinly") or its comparative "latinius" ("in better Latin", literally "more Latinly").


title: Classical Latin

text: "Latinitas" was spoken and written. It was the language taught in schools. Prescriptive rules therefore applied to it, and when special subjects like poetry or rhetoric were taken into consideration, additional rules applied. Since spoken "Latinitas" has become extinct (in favor of subsequent registers), the rules of "politus" (polished) texts may give the appearance of an artificial language. However, "Latinitas" was a form of "sermo" (spoken language), and as such, retains spontaneity. No texts by Classical Latin authors are noted for the type of rigidity evidenced by stylized art, with the exception of repetitious abbreviations and stock phrases found on inscriptions.


title: Classical Latin

text: "Good Latin" in philology is known as "classical" Latin literature. The term refers to the canonical relevance of literary works written in Latin in the late Roman Republic, and early to middle Roman Empire. "[T]hat is to say, that of belonging to an exclusive group of authors (or works) that were considered to be emblematic of a certain genre." The term "classicus" (masculine plural "classici") was devised by the Romans to translate Greek ἐγκριθέντες (encrithentes), and "select" which refers to authors who wrote in a form of Greek that was considered model. Before then, the term "classis", in addition to being a naval fleet, was a social class in one of the diachronic divisions of Roman society in accordance with property ownership under the Roman constitution. The word is a transliteration of Greek κλῆσις (clēsis, or "calling") used to rank army draftees by property from first to fifth class.


title: Classical Latin

text: "Classicus" refers to those in the "primae classis" ("first class"), such as the authors of polished works of "Latinitas", or "sermo urbanus". It contains nuances of the certified and the authentic, or "testis classicus" ("reliable witness"). It was under this construct that Marcus Cornelius Fronto (an African-Roman lawyer and language teacher) used "scriptores classici" ("first-class" or "reliable authors") in the second century AD. Their works were viewed as models of good Latin. This is the first known reference (possibly innovated during this time) to Classical Latin applied by authors, evidenced in the authentic language of their works.


title: Classical Latin

text: Imitating Greek grammarians, Romans such as Quintilian drew up lists termed "indices" or "ordines" modeled after the ones created by the Greeks, which were called "pinakes". The Greek lists were considered classical, or "recepti scriptores" ("select writers"). Aulus Gellius includes authors like Plautus, who are considered writers of Old Latin and not strictly in the period of classical Latin. The classical Romans distinguished Old Latin as "prisca Latinitas" and not "sermo vulgaris". Each author's work in the Roman lists was considered equivalent to one in the Greek. In example, Ennius was the Latin Homer, Aeneid was the equivalent of Iliad, etc. The lists of classical authors were as far as the Roman grammarians went in developing a philology. The topic remained at that point while interest in the "classici scriptores" declined in the medieval period as the best form of the language yielded to medieval Latin, inferior to classical standards.


title: Classical Latin

text: The Renaissance saw a revival in Roman culture, and with it, the return of Classic ("the best") Latin. Thomas Sébillet's "Art Poétique" (1548), "les bons et classiques poètes françois", refers to Jean de Meun and Alain Chartier, who the first modern application of the words. According to Merriam Webster's "Collegiate Dictionary", the term classical (from "classicus)" entered modern English in 1599, some 50 years after its re-introduction to the continent. In Governor William Bradford's "Dialogue" (1648), he referred to synods of a separatist church as "classical meetings", defined by meetings between "young men" from New England and "ancient men" from Holland and England. In 1715, Laurence Echard's "Classical Geographical Dictionary" was published. In 1736, Robert Ainsworth's "Thesaurus Linguae Latinae Compendarius" turned English words and expressions into "proper and classical Latin." In 1768, David Ruhnken's "Critical History of the Greek Orators" recast the molded view of the classical by applying the word "canon" to the "pinakes" of orators after the Biblical canon, or list of authentic books of the Bible. In doing so, Ruhnken had secular catechism in mind.


title: Classical Latin

text: In 1870, Wilhelm Sigismund Teuffel's "Geschichte der Römischen Literatur" ("A History of Roman Literature") defined the philological notion of classical Latin through a typology similar to the Ages of Man, setting out the Golden and Silver Ages of classical Latin. Wilhem Wagner, who published Teuffel's work in German, also produced an English translation which he published in 1873. Teuffel's classification, still in use today (with modifications), groups classical Latin authors into periods defined by political events rather than by style.


title: Classical Latin

text: Teuffel went on to publish other editions, but the English translation of "A History of Roman Literature" gained immediate success.


title: Classical Latin

text: In 1877, Charles Thomas Cruttwell produced a similar work in English. In his preface, Cruttwell notes "Teuffel's admirable history, without which many chapters in the present work could not have attained completeness." He also credits Wagner.


title: Classical Latin

text: Cruttwell adopts the time periods found in Teuffel's work, but he presents a detailed analysis of style, whereas Teuffel was more concerned with history. Like Teuffel, Cruttwell encountered issues while attempting to condense the voluminous details of time periods in an effort to capture the meaning of phases found in their various writing styles. Like Teuffel, he has trouble finding a name for the first of the three periods (the current Old Latin phase), calling it "from Livius to Sulla." He says the language "is marked by immaturity of art and language, by a vigorous but ill-disciplined imitation of Greek poetical models, and in prose by a dry sententiousness of style, gradually giving way to a clear and fluent strength..." These abstracts have little meaning to those not well-versed in Latin literature. In fact, Cruttwell admits "The ancients, indeed, saw a difference between Ennius, Pacuvius, and Accius, but it may be questioned whether the advance would be perceptible by us."


title: Classical Latin

text: In time, some of Cruttwell's ideas become established in Latin philology. While praising the application of rules to classical Latin (most intensely in the Golden Age, he says "In gaining accuracy, however, classical Latin suffered a grievous loss. It became cultivated as distinct from a natural language... Spontaneity, therefore, became impossible and soon invention also ceased... In a certain sense, therefore, Latin was studied as a dead language, while it was still a living."


title: Classical Latin

text: Also problematic in Teuffel's scheme is its appropriateness to the concept of classical Latin. Cruttwell addresses the issue by altering the concept of the classical. The "best" Latin is defined as "golden" Latin, the second of the three periods. The other two periods (considered "classical") are left hanging. By assigning the term "pre-classical" to Old Latin and implicating it to post-classical (or post-Augustan) and silver Latin, Cruttwell realized that his construct was not accordance with ancient usage and assertions: "[T]he epithet classical is by many restricted to the authors who wrote in it [golden Latin]. It is best, however, not to narrow unnecessarily the sphere of classicity; to exclude Terence on the one hand or Tacitus and Pliny on the other, would savour of artificial restriction rather than that of a natural classification." The contradiction remains—Terence is, and is not a classical author, depending on the context.


title: Classical Latin

text: Teuffel's definition of the "First Period" of Latin was based on inscriptions, fragments, and the literary works of the earliest known authors. Though he does use the term "Old Roman" at one point, most of these findings remain unnamed. Teuffel presents the Second Period in his major work, "das goldene Zeitalter der römischen Literatur" ("Golden Age of Roman Literature"), dated 671–767 AUC (83 BC – 14 AD), according to his own recollection. The timeframe is marked by the dictatorship of Lucius Cornelius Sulla Felix and the death of the emperor Augustus. Wagner's translation of Teuffel's writing is as follows:


title: Classical Latin

text: The Ciceronian Age was dated 671–711 AUC (83–43 BC), ending just after the death of Marcus Tullius Cicero. The Augustan 711–67 AUC (43 BC – 14 AD) ends with the death of Augustus. The Ciceronian Age is further divided by the consulship of Cicero in 691 AUC (63 BC) into a first and second half. Authors are assigned to these periods by years of principal achievements.


title: Classical Latin

text: The Golden Age had already made an appearance in German philology, but in a less systematic way. In a translation of Bielfeld's "Elements of universal erudition" (1770):The Second Age of Latin began about the time of Caesar [his ages are different from Teuffel's], and ended with Tiberius. This is what is called the Augustan Age, which was perhaps of all others the most brilliant, a period at which it should seem as if the greatest men, and the immortal authors, had met together upon the earth, in order to write the Latin language in its utmost purity and perfection... and of Tacitus, his conceits and sententious style is not that of the golden age...Evidently, Teuffel received ideas about golden and silver Latin from an existing tradition and embedded them in a new system, transforming them as he thought best.


title: Classical Latin

text: In Cruttwell's introduction, the Golden Age is dated 80 BC – 14 AD (from Cicero to Ovid), which corresponds to Teuffel's findings. Of the "Second Period," Cruttwell paraphrases Teuffel by saying it "represents the highest excellence in prose and poetry." The Ciceronian Age (known today as the "Republican Period") is dated 80–42 BC, marked by the Battle of Philippi. Cruttwell omits the first half of Teuffel's Ciceronian, and starts the Golden Age at Cicero's consulship in 63 BC—an error perpetuated in Cruttwell's second edition. He likely meant 80 BC, as he includes Varro in Golden Latin. Teuffel's Augustan Age is Cruttwell's Augustan Epoch (42 BC – 14 AD).


title: Classical Latin

text: The literary histories list includes all authors from Canonical to the Ciceronian Age—even those whose works are fragmented or missing altogether. With the exception of a few major writers, such as Cicero, Caesar, Virgil and Catullus, ancient accounts of Republican literature praise jurists and orators whose writings, and analyses of various styles of language cannot be verified because there are no surviving records. The reputations of Aquilius Gallus, Quintus Hortensius Hortalus, Lucius Licinius Lucullus, and many others who gained notoriety without readable works, are presumed by their association within the Golden Age. A list of canonical authors of the period whose works survived in whole or in part is shown here:


title: Classical Latin

text: The Golden Age is divided by the assassination of Julius Caesar. In the wars that followed, a generation of Republican literary figures was lost. Cicero and his contemporaries were replaced by a new generation who spent their formidable years under the old constructs, and forced to make their mark under the watchful eye of a new emperor. The demand for great orators had ceased, shifting to an emphasis on poetry. Other than the historian Livy, the most remarkable writers of the period were the poets Virgil, Horace, and Ovid. Although Augustus evidenced some toleration to republican sympathizers, he exiled Ovid, and imperial tolerance ended with the continuance of the Julio-Claudian dynasty.


title: Classical Latin

text: In his second volume, "Imperial Period", Teuffel initiated a slight alteration in approach, making it clear that his terms applied to Latin and not just to the period. He also changed his dating scheme from AUC to modern BC/AD. Though he introduces "das silberne Zeitalter der römischen Literatur", (The Silver Age of Roman Literature) from the death of Augustus to the death of Trajan (14–117 AD), he also mentions parts of a work by Seneca the Elder, a "wenig Einfluss der silbernen Latinität" (a slight influence of silver Latin). It's clear that his mindset had shifted from Golden and Silver Ages to Golden and Silver Latin, also to include "Latinitas", which at this point must be interpreted as Classical Latin. He may have been influenced in that regard by one of his sources E. Opitz, who in 1852 had published "specimen lexilogiae argenteae latinitatis", which includes Silver Latinity. Though Teuffel's First Period was equivalent to Old Latin and his Second Period was equal to the Golden Age, his Third Period "die römische Kaiserheit" encompasses both the Silver Age and the centuries now termed Late Latin, in which the forms seemed to break loose from their foundation and float freely. That is, men of literature were confounded about the meaning of "good Latin." The last iteration of Classical Latin is known as Silver Latin. The Silver Age is the first of the Imperial Period, and is divided into "die Zeit der julischen Dynastie ("14–68); "die Zeit der flavischen Dynastie" (69–96), and "die Zeit des Nerva und Trajan" (96–117). Subsequently, Teuffel goes over to a century scheme: 2nd, 3rd, etc., through 6th. His later editions (which came about towards the end of the 19th century) divide the Imperial Age into parts: 1st century (Silver Age), 2nd century ( the Hadrian and the Antonines), and the 3rd through 6th centuries. Of the Silver Age proper, Teuffel points out that anything like freedom of speech had vanished with Tiberius:


title: Classical Latin

text: The content of new literary works was continually proscribed by the emperor, who exiled or executed existing authors and played the role of literary man, himself (typically badly). Artists therefore went into a repertory of new and dazzling mannerisms, which Teuffel calls "utter unreality." Cruttwell picks up this theme:


title: Classical Latin

text: In Cruttwell's view (which had not been expressed by Teuffel), Silver Latin was a "rank, weed-grown garden," a "decline." Cruttwell had already decried what he saw as a loss of spontaneity in Golden Latin. Teuffel regarded the Silver Age as a loss of natural language, and therefore of spontaneity, implying that it was last seen in the Golden Age. Instead, Tiberius brought about a "sudden collapse of letters." The idea of a decline had been dominant in English society since Edward Gibbon's "Decline and Fall of the Roman Empire". Once again, Cruttwell evidences some unease with his stock pronouncements: "The "Natural History" of Pliny shows how much remained to be done in fields of great interest." The idea of Pliny as a model is not consistent with any sort of decline. Moreover, Pliny did his best work under emperors who were as tolerant as Augustus had been. To include some of the best writings of the Silver Age, Cruttwell extended the period through the death of Marcus Aurelius (180 AD). The philosophic prose of a good emperor was in no way compatible with either Teuffel's view of unnatural language, or Cruttwell's depiction of a decline. Having created these constructs, the two philologists found they could not entirely justify them. Apparently, in the worst implication of their views, there was no such thing as Classical Latin by the ancient definition, and some of the very best writing of any period in world history was deemed stilted, degenerate, unnatural language.


title: Classical Latin

text: The Silver Age furnishes the only two extant Latin novels: Apuleius's "The Golden Ass" and Petronius's "Satyricon".


title: Classical Latin

text: Of the additional century granted by Cruttwell to Silver Latin, Teuffel says: "The second century was a happy period for the Roman State, the happiest indeed during the whole Empire... But in the world of letters the lassitude and enervation, which told of Rome's decline, became unmistakeable... its forte is in imitation." Teuffel, however, excepts the jurists; others find other "exceptions", recasting Teuffels's view.


title: Classical Latin

text: Style of language refers to repeatable features of speech that are somewhat less general than the fundamental characteristics of a language. The latter provides unity, allowing it to be referred to by a single name. Thus Old Latin, Classical Latin, Vulgar Latin, etc., are not considered different languages, but are all referred to by the term, Latin. This is an ancient practice continued by moderns rather than a philological innovation of recent times. That Latin had case endings is a fundamental feature of the language. Whether a given form of speech prefers to use prepositions such as "ad", "ex", "de," for "to," "from" and "of" rather than simple case endings is a matter of style. Latin has a large number of styles. Each and every author has a style, which typically allows his prose or poetry to be identified by experienced Latinists. Problems in comparative literature have risen out of group styles finding similarity by period, in which case one may speak of Old Latin, Silver Latin, Late Latin as styles or a phase of styles.


title: Classical Latin

text: The ancient authors themselves first defined style by recognizing different kinds of "sermo", or "speech". By valuing Classical Latin as "first class", it was better to write with "Latinitas" selected by authors who were attuned to literary and upper-class languages of the city as a standardized style. All "sermo" that differed from it was a different style. Thus, in rhetoric, Cicero was able to define sublime, intermediate, and low styles within Classical Latin. St. Augustine recommended low style for sermons. Style was to be defined by deviation in speech from a standard. Teuffel termed this standard "Golden Latin".


title: Classical Latin

text: John Edwin Sandys, who was an authority in Latin style for several decades, summarizes the differences between Golden and Silver Latin as follows:


title: Pittsburgh International Airport

text: Pittsburgh International Airport , formerly Greater Pittsburgh International Airport, is a civil–military international airport in Findlay Township and Moon Township, Pennsylvania. Located about 10 miles (15 km) west of downtown Pittsburgh, it is the primary international airport serving the Greater Pittsburgh Region as well as adjacent areas in West Virginia and Ohio. The airport is owned and operated by the Allegheny County Airport Authority and offers passenger flights to destinations throughout North America and Europe. PIT has four runways and covers .


title: Pittsburgh International Airport

text: First opened in 1952, the airport was initially served by five airlines and became a small hub for Trans World Airlines for over two decades. The airport underwent a massive $1 billion rebuilding and expansion which was largely designed to US Airways' specification so it could become one of their major hubs. Completed in 1992, the new airport was one of the most innovative in the world, dubbed the "airport of the future" by the "New York Times", and helped to pioneer modern airport design with its X-shape to reduce distance between gates, underground tram to transport passengers around the airport, and array of shopping options, all of which were cutting-edge at the time. Traffic peaked at 20 million passengers in the late 1990s, and US Air peaked at 542 flights and 11,995 employees at the airport in 2001, and the airport was an important pillar of the Pittsburgh economy. However, the downturn in air travel immediately after September 11 attacks badly harmed US Airways' financial state. US Air declared chapter 11 bankruptcy twice in a row, and abandoned Pittsburgh as a hub in 2004, eliminating thousands of jobs and nearly bankrupting the airport itself, which was built largely to suit US Airways' needs. However, US Air's diminished capacity at Pittsburgh opened the door for other airlines to expand operations and better serve local Pittsburgh-area passengers rather than focus on connecting passengers.


title: Pittsburgh International Airport

text: The airport experienced a resurgence in the 2010s, doubling the number of carriers to 16 as the Allegheny County Airport Authority has aggressively courted airlines and lobbied for new passenger routes. Southwest Airlines has increased its presence at the airport in recent years, overtaking American Airlines (which US Airways acquired and merged with) as the largest carrier in terms of passengers. The airport is also a hub for regional carrier Southern Airways Express. Cargo operations have increased at the airport in recent years.


title: Pittsburgh International Airport

text: In 2017, the airport became the first in the country to reopen access to the post-security terminal for individuals who are not flying, as long as they can pass through security, after the federal government lifted restrictions put in place after 9/11.


title: Pittsburgh International Airport

text: In 2021, the airport became the first in the world with its own microgrid, which provides power to the entire airport with natural gas and solar power.


title: Pittsburgh International Airport

text: The airport is currently undergoing a $1.39 billion renovation which will include a new terminal for check-in, security, and baggage claim adjacent to the gates. The renovation will eliminate the need for the tram and increase the number of parking spaces. Officials emphasized that the renovations would make the airport more suited to Pittsburgh, rather than to US Airways. First announced in 2017 and delayed due to the coronavirus pandemic, the renovation resumed in 2021 and is now projected to open in 2025. The project will not use any local tax dollars, and airlines will pay most of the costs.


title: Pittsburgh International Airport

text: Until the beginning of World War II, Moon Township was mostly a rural agricultural area. It was not considered a suburb of downtown Pittsburgh as it was too distant. It was served solely by Pittsburgh-based state and federal services and media. In the early 1920s, John A. Bell of Carnegie purchased a number of small farms in Moon and established a commercial dairy farm on his of land. He was bought out by E.E. Rieck and his wife, and C.F. Nettrour, owners of the established Rieck's Dairy. They doubled the number of cattle at the farm.


title: Pittsburgh International Airport

text: Around 1940, the federal government, through the Works Progress Administration (WPA), determined that the Pittsburgh area needed a military airport to defend the industrial wealth of the area and to provide a training base and stop-over facility. The administration of President Franklin D. Roosevelt was continuing to invest in infrastructure across the country in the waning years of the Great Depression, before the US entered World War II, which had started in 1939. The agricultural expanses of Moon Township were attractive to airport planners in the city. The Civil Aeronautics Administration proposed $2.6 million to the county for a $6 million field in August 1941 ($ and $ present day dollars). The county bought the Bell Farm, and federal agencies began construction of the runways on 20 April 1942, after the US had entered the war.


title: Pittsburgh International Airport

text: In 1944, Allegheny County officials proposed to expand the military airport with the addition of a commercial passenger terminal to relieve the Allegheny County Airport, which was built in 1926 and was becoming too small. Ground was broken on the new passenger terminal on 18 July 1946. The new terminal would eventually cost $33 million ($ present day dollars) and was built entirely by Pittsburgh-area companies. The new airport, christened as Greater Pittsburgh Airport (renamed Greater Pittsburgh International Airport in 1972 upon the opening of the International Arrivals Building) opened on 31 May 1952. The first flight was on 3 June 1952. In its first full year of operation in 1953, more than 1.4 million passengers used the terminal. "Greater Pitt" was then considered modern and spacious. The airport terminal was the largest in the United States, second only to Idlewild Airport's (now JFK Airport) in New York when it was completed five years later. The airport's capacity is one of its most valuable assets.


title: Pittsburgh International Airport

text: The airport was designed by local architect Joseph W. Hoover. One of the features of his style is the use of simple, exposed concrete, steel, and glass materials. The terminal building was constructed in "stepped" levels: the first floor extended farther than the second, the second floor extended farther than the third, etc. Such a design meant that the uncovered roof of the lower level could be an observation deck. In addition to the observation decks, the rounded "Horizon Room" was on the fourth floor with a commanding view of the airport. The interior of the terminal building was in the contemporary International Style, as was the exterior. One of the memorable features of the lobby was the large compass laid in the floor with green and yellow-orange terrazzo. A mobile by Alexander Calder was another decorative feature of the lobby. The mobile hangs in the center core of the new airside terminal. A re-creation of the compass was installed in the new terminal at an exhibit dedicated to old "Greater Pitt".


title: Pittsburgh International Airport

text: The first five airlines of the Greater Pittsburgh Airport were Trans World Airlines (TWA), Capital Airlines (later part of United), Northwest, All American (later Allegheny Airlines, then USAir, and finally US Airways), and Eastern Airlines. The April 1957 Airline Guide shows 58 weekday departures on Capital, 54 TWA, 18 Allegheny, 8 United, 7 Eastern, 4 Northwest, 3 American and 2 Lake Central. The first jets in service at Pittsburgh were TWA 707s on a Los Angeles-Chicago-Pittsburgh loop in summer 1959.


title: Pittsburgh International Airport

text: The 1956 diagram shows runway 10/28 7500 ft, 5/23 5766 ft and 14/32 5965 ft. The longest runway was still 7500 ft when jets started in 1959 but was soon extended to 8000 ft. The 10500-ft runway 10L was added by 1965.


title: Pittsburgh International Airport

text: In 1959, the east dock was added to the terminal. On 1 July 1968, international airport status was obtained with the dedication of the first customs office at the complex. Ground was broken for the International Wing, west of the original terminal building, in 1970. It opened in 1972 to accommodate federal inspection services; international flights (Nordair 737s to Canada) began in 1971. The airport expanded as load increased. In 1972, rotundas were added to the end of each dock to allow more gates. In the later 1970s growth in regional air travel created a need for more gates. In 1980 the South East Dock was opened. Even with these expansions, the terminal was too small.


title: Pittsburgh International Airport

text: From the 1960s to about 1985, TWA operated a small hub at Pittsburgh. The carrier introduced the first nonstop route from the city to Europe, a Lockheed L-1011 service to London, in May 1981. Nevertheless, the flight lasted only four months; TWA stated that too few passengers were traveling in first class, rendering the service unprofitable. In 1985, British Airways announced that it would start operating Boeing 747s to London via Washington, D.C., later that year. Two days before the maiden flight, the airline sent one of its Concordes to Pittsburgh to celebrate the launch of the route.


title: Pittsburgh International Airport

text: In 1987, with the financial backing of USAir (then the dominant carrier in Pittsburgh), work commenced on a billion-dollar expansion which was designed by Tasso Katselas Associates, Inc. Three years later, USAir inaugurated a link to Frankfurt, signaling the resumption of nonstop transatlantic service from the airport. The route benefited the various West German companies that had offices in the city.


title: Pittsburgh International Airport

text: On 1 October 1992, the new terminal opened, with operations having been transferred overnight from the old terminal. (The old terminal was kept until 1999 to house remaining operations offices.) The new terminal had numerous innovative features, including an AirMall, with more than 100 retailers and eateries. The air mall and underground tram were considered cutting-edge. The new landside/airside design construction eliminated the need for connecting passengers to go through security more than once. The airport was equipped to handle up to 35 million passengers per year. The modern and innovative Pittsburgh airport became a model for other airports around the world. Its design simplified aircraft movement on the airfield and enabled easy pedestrian traffic to the gates.


title: Pittsburgh International Airport

text: US Air expanded with the new airport, and by 1995 they had nonstops from PIT to 91 airports, plus 28 more on USAir Express. In 1997 the airport handled almost 21 million passengers, more than any previous year. By the late 1990s growth had leveled off, with USAir concentrating on expanding at Philadelphia and Charlotte/Douglas International Airport, which had been a hub airport of Piedmont Airlines.


title: Pittsburgh International Airport

text: In August 2001, the airport had its busiest month ever with 2 million passengers and an average of 633 daily flights, and was on track for 2001 to be its busiest year ever. Then the September 11 attacks harmed the aviation industry, and US Air in particular, setting in motion the decline of Pittsburgh as a hub. US Air began slashing jobs a week after the attacks and filed for chapter 11 bankruptcy reorganization in 2002. High operating costs at the airport put the US Airways hub in Pittsburgh at a serious disadvantage. By 2003, US Airways reported to be running a $40 million loss per year ($ present day dollars) operating its hub at Pittsburgh, while also paying roughly 80% of the new airport's $673 million debt ($ present day dollars) stemming from its requested construction of the new terminals.


title: Pittsburgh International Airport

text: Just before emerging from bankruptcy in 2003, US Air canceled its leases at Pittsburgh without any notice to airport and county officials, a move that former Allegheny County Airport Authority executive director said was "completely immoral and unethical" in a 2021 interview. US Air filed for bankruptcy again in September 2004. Two months later, the carrier ceased service to London and Frankfurt, leaving the airport without any flights to Europe. After failed negotiations to lower landing fees and debt obligations, the airline announced in December 2004 that it would be reducing operations at Pittsburgh, shifting hub operations to Charlotte and Philadelphia. By the end of 2005 the airline had eliminated 7,000 jobs while operating roughly 200 flights per day, mostly domestic. A year later, US Airways had only about 170 flights per day to and from Pittsburgh, most being domestic flights. Unrelenting flight and job cuts continued through the decade; accompanied by the airline's closure of Concourse E on the Landside Terminal and a portion of Concourse A on the Airside Terminal. In 2007, US Air's market share in Pittsburgh dropped below 40% for the first time since the airport's expansion in 1992. By the end of the decade, US Airways had reduced to 68 flights per day, operating from ten gates on Concourse B, and one US Airways Club location. Numerous US Airways ticketing and customer service counters were abandoned, and 15 gates on Concourse A and B were sealed off from the rest of the airport. Pittsburgh's air traffic bottomed out in 2013 with 7.8 million passengers and 36 destinations.


title: Pittsburgh International Airport

text: Despite de-hubbing the airport, US Airways chose Pittsburgh in 2008 for their systemwide flight operations control center, after a bidding war with Charlotte and Phoenix led to state and local subsidies totaling $16.25 million being offered to US Air to build the center at Pittsburgh. The center worked on emergency operations for US Airways Flight 1549 after it landed in the Hudson River. The airline closed the center in 2015 as part of its merger with American Airlines. (The center was rebuilt as a 9-1-1 center for Allegheny County, which opened in 2019.)


title: Pittsburgh International Airport

text: Since the wind down of US Airways hub at Pittsburgh, new low cost carriers have been able to enter the market, creating more choices for local passengers. Pittsburgh has also been successful in attracting airlines to serve the region for the first time or to return to the market. Allegiant Air commenced service in February 2015 and established a base of operations later that year. Frontier Airlines re-entered the Pittsburgh airport in 2016 after a four-year absence. Spirit Airlines commenced service to seven destinations in 2017. Alaska Airlines began service in 2019 with a nonstop route to Seattle/Tacoma. In July 2021, Breeze Airways began nonstop service to four cities. In October 2021, Sun Country Airlines announced it would enter the Pittsburgh market with service to its hub at Minneapolis/St. Paul.


title: Pittsburgh International Airport

text: Starting in September 2017, non-ticketed persons were allowed to access the airside terminal and gates, similar to pre-9/11 policy. Pittsburgh was the first airport (since 9/11) in the nation to allow non-passengers to pass through security to dine and shop in a post-security terminal. Participants can sign up for myPITpass on the airport's website and must pass through the alternate security checkpoint before continuing through to the Airmall in the airside terminal. The airport became one of the first in the United States to use a new TSA system called Credential Authentication Technology, which phases out the use of boarding passes at TSA security checkpoints in favor of a stronger system that verifies passengers based solely on a government-issued ID.


title: Pittsburgh International Airport

text: In 2017, Pittsburgh was the first U.S. airport to be named Airport of the Year by "Air Transport World".


title: Pittsburgh International Airport

text: During the winter of 2020–2021, both British Airways and the German airline Condor indefinitely suspended their flights to Pittsburgh. As a result, the airport once more lacked a nonstop connection to Europe. British Airways ultimately resumed its route to Heathrow Airport in June 2022.


title: Pittsburgh International Airport

text: In September 2017, Allegheny County Airport Authority officials announced a $1.1 billion plan to renovate and reconfigure the terminal complex, including a new landside terminal and a new parking garage. Under the proposal, the current landside building would be demolished if another use is not found, and the number of gates would be reduced from 75 to 51. A new landside building would be constructed between the airside terminal's concourses C and D, with new security and baggage facilities, a new international arrivals area, and many other amenities to serve passengers. The board chairman of the Airport Authority, David Minnotte, said that "The people of Pittsburgh finally get an airport built for them and not USAir". No taxpayer dollars would be used to construct the new facility, and it will be instead financed with floating bonds, grants, passenger facility charges, and revenue from natural gas drilling on airport property.


title: Pittsburgh International Airport

text: Construction was originally expected to begin in summer 2020 and the new terminal was slated to open in 2023. However, in April 2020 airport officials decided to delay the selling of bonds and start of construction due to the coronavirus pandemic. In February 2021, airport officials announced early site and construction work would begin in spring 2021 with an increased budget of $1.39 billion. The airlines serving the airport agreed to fund $182 million in construction site preparation work for the project. Construction finally began in July 2021 and the project is expected to be completed in 2025.


title: Pittsburgh International Airport

text: PIT has a wide, open layout and four runways: three east–west parallel runways and a fourth crosswind runway. The airport's two longest runways are and , allowing PIT to accommodate the largest airliners. Because of the development of non-aviation related business on airport land, PIT can add only one more runway (this number was as high as four in the past). With three parallel runways, simultaneous landings and/or departures can be performed in nearly any situation.


title: Pittsburgh International Airport

text: Runways 10L and 10R have Category III ILS (Instrument Landing System) approaches. Runway 28R is certified for Category I ILS and is authorized for Category II approaches but requires special aircrew and aircraft certification. Runways 28L and 32 have Category I ILS approaches. All runways have GPS approaches as well.


title: Pittsburgh International Airport

text: The airport complex consists of two main buildings, the "Landside Terminal" and the "Airside Terminal". The terminal consists of 75 gates on four concourses; however, only 56 gates are available for use. After passing through the security checkpoint, passengers board one of two underground people movers that travel to the Airside Terminal, where all departure gates are located. All international arrivals, except for cities with United States border preclearance, pass through Concourse C. American Airlines has an Admirals Club on the mezzanine level of the airside terminal. The Club Lounge opened in October 2017 in the C Concourse across from gate C-52 near the center core and was renovated and expanded in 2019. The airport also operates a free lounge for active duty military and veterans in concourse C.


title: Pittsburgh International Airport

text: There is an AirMall in the airside terminal, operated by Fraport, with numerous retail stores and restaurants. It was one of the first of its kind in an airport and paved the way for similar shopping experiences at other airports. Tenants in the airport are required to charge the same amount as they do at non-airport locations. Before 9/11, anyone could shop in the airport, but it was closed to non-travelers after 9/11. In 2017, the AirMall was reopened to non-travelers who obtained a free access pass from the airport.


title: Pittsburgh International Airport

text: PIT is located at Exit 53 of Interstate 376 and the Western Terminus Pennsylvania Route 576 (future I-576), and within of Interstate 79 and of Interstate 76, the Pennsylvania Turnpike. Interstate 70 to the south and Interstate 80 to the north are both less than an hour away. Just beyond Interstates 70 and 80, Interstate 77 to the west and Interstate 68 to the south are within 90 minutes of the airport.


title: Pittsburgh International Airport

text: PIT offers on-site parking operated by the Grant Oliver Corporation and patrolled by the Allegheny County Police. Grant Oliver offers a GO FAST Pass account to pay for parking electronically via E-ZPass, with billing and other aspects of the system handled by Grant Oliver. There are regular parking shuttles to the Long Term and Extended lots that can be accessed from the Baggage Claim level of the Landside Terminal. There are four options for parking: Short Term, Long Term, Extended, and Economy. The economy option was added in 2021. The short term garage has 2100 spaces and is attached to the landside terminal via the enclosed moving walkway. The long term section is also connected to the enclosed moving walkway and has 3,100 spaces available. The extended and economy sections have an outdoor walkway that leads to the enclosed moving walkway and have 8,000 spaces available.


title: Pittsburgh International Airport

text: Bus service is also available from Downtown Pittsburgh and the city's University District (Oakland) via the Port Authority of Allegheny County's 28X Route. Mountain Line Transit's Grey Line also has service to areas south of Pittsburgh including Waynesburg, Pennsylvania; Morgantown, Fairmont, and Clarksburg, West Virginia. BCTA Transit formerly served locations north and westbound from the airport. The Pittsburgh Light Rail currently does not stop at the airport.


title: Pittsburgh International Airport

text: Pittsburgh International Airport has a sizeable freight business, with a Free-trade zone of , access to three class-one railroad freight lines, one interstate highway, and a location a few miles from the nation's second largest inland port and within 500 miles of 80% of the nation's population. Four cargo buildings provide more than of warehouse capacity and over of apron space. The airport has begun construction on a new 80,000 sq ft cargo facility with 17 loading docks, scheduled to open in 2024.


title: Pittsburgh International Airport

text: Cargo traffic has increased considerably in recent years as airport officials have pitched Pittsburgh to cargo carriers as a more efficient alternative to clogged hubs like New York and Chicago. In 2017, Qatar Airways launched twice-weekly cargo service at Pittsburgh, backed by $1.5 million in subsidies. The effort was not very successful at first as Qatar failed to meet tonnage goals, and in December 2019 the route was suspended. However, Qatar resumed the flight in 2020 without any subsidies, and as of 2022 had increased operations to 3-4 flights per week. Several new cargo carriers began service to Pittsburgh in 2020 and 2021, including Cathay Pacific, SpiceXpress, and Amazon Air. In 2021, nearly 250 million pounds of cargo goods touched down at PIT, the largest figure since 2004 and a 30% increase over 2020.


title: Pittsburgh International Airport

text: The world's leading caterer for air and business, LSG SkyChefs, in 2007 chose Pittsburgh as its sole Western Hemisphere manufacturing facility. It expanded its customer service center on the cargo side of the airport by and now employs over 100 people with the capacity of making nearly 25 million meals per year for distribution to flights all over the Americas. LSG SkyChefs cited the region's strategic location for air and truck transport to major suppliers and customers, as well as the airport's excellent record in maintaining and expanding capacity.


title: Pittsburgh International Airport

text: In 2018, the airport announced plans to construct its own microgrid, using natural gas and solar power as the primary power source for the airport, protecting it from power outages. In 2019, the airport authority awarded Peoples Natural Gas a 20-year contract to build, maintain, and operate the microgrid at no cost to the airport in exchange for the required land and an agreement to purchase the electricity for 20 years. The microgrid was completed in July 2021, making Pittsburgh the first airport in the world to receive its electricity entirely from a microgrid. The microgrid uses natural gas from the Marcellus Shale as well as solar panels. Most of the energy comes from natural gas; the 9,360 solar panels can generate up to 13% of its peak power. In its first year, the microgrid saved the airport an estimated $1 million in energy costs.


title: Pittsburgh International Airport

text: In 2019, the airport announced the development of Neighborhood 91, a 195-acre hub for additive manufacturing on airport grounds. It is so named because Pittsburgh has 90 distinct neighborhoods. The development will house a complete end-to-end supply chain allowing products to be manufactured and finished in one place and then shipped around the world from the airport. The site is being developed as part of a partnership with the University of Pittsburgh and will have 1.4 million square feet of manufacturing and office space.


title: Pittsburgh International Airport

text: A Hyatt Regency hotel is located onsite and is directly connected to the landside terminal via moving walkway. The hotel also has a ballroom and meeting facilities. As part of a pilot program, hotel guests were allowed access to the post-security shops and restaurants without an airline ticket as long as they could pass through security. In 2017, airport officials opened post-security access to all non-flying persons who could pass through security, including hotel guests. A Sunoco-branded gas station is also located onsite. Both the hotel and the gas station draw power from the airport's microgrid.


title: Pittsburgh International Airport

text: American Airlines still has a maintenance base at Pittsburgh, which dates back to the US Air days and employs 500 people. American Airlines maintains and repairs all its Airbus narrowbody fleet at Pittsburgh. In 2021, it extended its lease at the airport for five years.


title: Pittsburgh International Airport

text: Through the first 11 months of 2021, FedEx accounted for 50% of all cargo traffic at the airport, followed by UPS at 33% and Amazon Air at 5%.


title: Pittsburgh International Airport

text: The airport has been the venue for a number of miscellaneous events. The U.S. Air Force has held several air shows at the airport.


title: Pittsburgh International Airport

text: In 1991, over 40,000 people packed the airport to greet the Pittsburgh Penguins when they landed at the airport after winning their first Stanley Cup championship.


title: Van der Waals equation

text: In chemistry and thermodynamics, the Van der Waals equation (or Van der Waals equation of state) is an equation of state which extends the ideal gas law to include the effects of interaction between molecules of a gas, as well as accounting for the finite size of the molecules.


title: Van der Waals equation

text: The ideal gas law treats gas molecules as point particles that interact with their containers but not each other, meaning they neither take up space nor change kinetic energy during collisions (i.e. all collisions are perfectly elastic). The ideal gas law states that the volume "V" occupied by "n" moles of any gas has a pressure "P" at temperature "T" given by the following relationship, where "R" is the gas constant:


title: Van der Waals equation

text: To account for the volume occupied by real gas molecules, the Van der Waals equation replaces formula_2 in the ideal gas law with formula_3, where "V" is the molar volume of the gas and "b" is the volume occupied by the molecules of one mole:


title: Van der Waals equation

text: The second modification made to the ideal gas law accounts for interaction between molecules of the gas. The Van der Waals equation includes intermolecular interaction by adding to the observed pressure "P" in the equation of state a term of the form formula_5, where "a" is a constant whose value depends on the gas.


title: Van der Waals equation

text: When the molar volume "V" is large, "b" becomes negligible in comparison with "V", "a/V" becomes negligible with respect to "P", and the Van der Waals equation reduces to the ideal gas law, "PV=RT".


title: Van der Waals equation

text: This equation approximates the behavior of real fluids above their critical temperatures and is qualitatively reasonable for their liquid and low-pressure gaseous states at low temperatures. However, near the phase transitions between gas and liquid, in the range of "p", "V", and "T" where the liquid phase and the gas phase are in equilibrium, the Van der Waals equation fails to accurately model observed experimental behavior. In particular, "p" is a constant function of "V" at given temperatures in these regions. As such, the Van der Waals model is not useful for calculations intended to predict real behavior in regions near critical points. Corrections to address these predictive deficiencies include the equal area rule and the principle of corresponding states.


title: Van der Waals equation

text: The Van der Waals equation is a thermodynamic equation of state based on the theory that fluids are composed of particles with non-zero volumes, and subject to a (not necessarily pairwise) inter-particle attractive force. It was based on work in theoretical physical chemistry performed in the late 19th century by Johannes Diderik van der Waals, who did related work on the attractive force that also bears his name. The equation is known to be based on a traditional set of derivations deriving from Van der Waals' and related efforts, as well as a set of derivation based in statistical thermodynamics, see below.


title: Van der Waals equation

text: Van der Waals' early interests were primarily in the field of thermodynamics, where a first influence was Rudolf Clausius's published work on heat in 1857; other significant influences were the writings by James Clerk Maxwell, Ludwig Boltzmann, and Willard Gibbs. After initial pursuit of teaching credentials, Van der Waals' undergraduate coursework in mathematics and physics at the University of Leiden in the Netherlands led (with significant hurdles) to his acceptance for doctoral studies at Leiden under Pieter Rijke. While his dissertation helps to explain the experimental observation in 1869 by Irish professor of chemistry Thomas Andrews (Queen's University Belfast) of the existence of a critical point in fluids, science historian Martin J. Klein states that it is not clear whether Van der Waals was aware of Andrews' results when he began his doctorate work.


title: Van der Waals equation

text: Van der Waals' doctoral research culminated in an 1873 dissertation that provided a semi-quantitative theory describing the gas-liquid change of state and the origin of a critical temperature, "Over de Continuïteit van den Gas- en Vloeistoftoestand" (Dutch; in English, "On the Continuity of the Gas and Liquid State"). It was in this dissertation that the first derivations of what we now refer to as the "Van der Waals equation" appeared. James Clerk Maxwell reviewed and lauded its published content in the British science journal "Nature", and Van der Waals began independent work that would result in his receipt of the Nobel Prize in 1910, which emphasized the contribution of his formulation of this "equation of state for gases and liquids".


title: Van der Waals equation

text: The equation relates four state variables: the pressure of the fluid "p", the total volume of the fluid's container "V", the number of particles "N", and the absolute temperature of the system "T".


title: Van der Waals equation

text: is the volume of the container occupied by each particle (not the velocity of a particle), and "k" is the Boltzmann constant. It introduces two new parameters: "a"′, a measure of the average attraction between particles, and "b"′, the volume excluded from "v" by one particle.


title: Van der Waals equation

text: A careful distinction must be drawn between the volume "available to" a particle and the volume "of" a particle. In the intensive equation, "v" equals the total space available to each particle, while the parameter "b"′ is proportional to the proper volume of a single particle – the volume bounded by the atomic radius. This is subtracted from "v" because of the space taken up by one particle. In Van der Waals' original derivation, given below, "b"' is four times the proper volume of the particle. Observe further that the pressure "p" goes to infinity when the container is completely filled with particles so that there is no void space left for the particles to move; this occurs when "V" = "nb".


title: Van der Waals equation

text: If a mixture of formula_22 gases is being considered, and each gas has its own formula_23 (attraction between molecules) and formula_24 (volume occupied by molecules) values, then formula_23 and formula_24 for the mixture can be calculated as


title: Van der Waals equation

text: and the rule of adding partial pressures becomes invalid if the numerical result of the equation formula_34 is significantly different from the ideal gas equation formula_35 .


title: Van der Waals equation

text: The equation in reduced form is exactly the same for every gas, this is consistent with the Theorem of corresponding states.


title: Van der Waals equation

text: This yields a critical compressibility factor of 3/8. Reasons for modification of ideal gas equation: The equation state for ideal gas is PV=RT. In the derivation of ideal gas laws on the basis of kinetic theory of gases some assumption have been made.


title: Van der Waals equation

text: The "Van der Waals equation" is mathematically simple, but it nevertheless predicts the experimentally observed transition between vapor and liquid, and predicts critical behaviour. It also adequately predicts and explains the Joule–Thomson effect (temperature change during adiabatic expansion), which is not possible in ideal gas.


title: Van der Waals equation

text: Above the critical temperature, "T", the Van der Waals equation is an improvement over the ideal gas law, and for lower temperatures, i.e., "T" < "T", the equation is also qualitatively reasonable for the liquid and low-pressure gaseous states; however, with respect to the first-order phase transition, i.e., the range of ("p, V, T") where a liquid phase and a gas phase would be in equilibrium, the equation appears to fail to predict observed experimental behaviour, in the sense that p is typically observed to be constant as a function of "V" for a given temperature in the two-phase region. This apparent discrepancy is resolved in the context of vapour–liquid equilibrium: at a particular temperature, there exist two points on the Van der Waals isotherm that have the same chemical potential, and thus a system in thermodynamic equilibrium will appear to traverse a straight line on the "p"–"V" diagram as the ratio of vapour to liquid changes. However, in such a system, there are really only two points present (the liquid and the vapour) rather than a series of states connected by a line, so connecting the locus of points is incorrect: it is not an equation of multiple states, but an equation of (a single) state. It is indeed possible to compress a gas beyond the point at which it would typically condense, given the right conditions, and it is also possible to expand a liquid beyond the point at which it would usually boil. Such states are called "metastable" states. Such behaviour is qualitatively (though perhaps not quantitatively) predicted by the Van der Waals equation of state.


title: Van der Waals equation

text: However, the values of physical quantities as predicted with the Van der Waals equation of state "are in very poor agreement with experiment", so the model's utility is limited to qualitative rather than quantitative purposes. Empirically-based corrections can easily be inserted into the Van der Waals model (see Maxwell's correction, below), but in so doing, the modified expression is no longer as simple an analytical model; in this regard, other models, such as those based on the principle of corresponding states, achieve a better fit with roughly the same work.


title: Van der Waals equation

text: Even with its acknowledged shortcomings, the pervasive use of the "Van der Waals equation" in standard university physical chemistry textbooks makes clear its importance as a pedagogic tool to aid understanding fundamental physical chemistry ideas involved in developing theories of vapour–liquid behavior and equations of state. In addition, other (more accurate) equations of state such as the Redlich–Kwong and Peng–Robinson equation of state are essentially modifications of the Van der Waals equation of state.


title: Van der Waals equation

text: Textbooks in physical chemistry generally give two derivations of the title equation. One is the conventional derivation that goes back to Van der Waals, a mechanical equation of state that cannot be used to specify all thermodynamic functions; the other is a statistical mechanics derivation that makes explicit the intermolecular potential neglected in the first derivation. A particular advantage of the statistical mechanical derivation is that it yields the partition function for the system, and allows all thermodynamic functions to be specified (including the mechanical equation of state).


title: Van der Waals equation

text: Consider one mole of gas composed of non-interacting point particles that satisfy the ideal gas law:(see any standard Physical Chemistry text, op. cit.)


title: Van der Waals equation

text: Next, assume that all particles are hard spheres of the same finite radius "r" (the Van der Waals radius). The effect of the finite volume of the particles is to decrease the available void space in which the particles are free to move. We must replace "V" by "V" − "b", where "b" is called the "excluded volume" (per mole) or "co-volume". The corrected equation becomes


title: Van der Waals equation

text: The excluded volume formula_24 is not just equal to the volume occupied by the solid, finite-sized particles, but actually four times the total molecular volume for one mole of a Van der waals' gas. To see this, we must realize that a particle is surrounded by a sphere of radius 2"r" (two times the original radius) that is forbidden for the centers of the other particles. If the distance between two particle centers were to be smaller than 2"r", it would mean that the two particles penetrate each other, which, by definition, hard spheres are unable to do.


title: Van der Waals equation

text: So "b′" is four times the proper volume of the particle. It was a point of concern to Van der Waals that the factor four yields an upper bound; empirical values for "b′" are usually lower. Of course, molecules are not infinitely hard, as Van der Waals thought, and are often fairly soft. To obtain the excluded volume per mole we just need to multiply by the number of molecules in a mole, i.e. by the avogadro number:


title: Van der Waals equation

text: Next, we introduce a (not necessarily pairwise) attractive force between the particles. Van der Waals assumed that, notwithstanding the existence of this force, the density of the fluid is homogeneous; furthermore, he assumed that the range of the attractive force is so small that the great majority of the particles do not feel that the container is of finite size. Given the homogeneity of the fluid, the bulk of the particles do not experience a net force pulling them to the right or to the left. This is different for the particles in surface layers directly adjacent to the walls. They feel a net force from the bulk particles pulling them into the container, because this force is not compensated by particles on the side where the wall is (another assumption here is that there is no interaction between walls and particles, which is not true, as can be seen from the phenomenon of droplet formation; most types of liquid show adhesion). This net force decreases the force exerted onto the wall by the particles in the surface layer. The net force on a surface particle, pulling it into the container, is proportional to the number density. On considering one mole of gas, the number of particles will be "N"


title: Van der Waals equation

text: The number of particles in the surface layers is, again by assuming homogeneity, also proportional to the density. In total, the force on the walls is decreased by a factor proportional to the square of the density, and the pressure (force per unit surface) is decreased by


title: Van der Waals equation

text: Upon writing "n" for the number of moles and "nV" = "V", the equation obtains the second form given above,


title: Van der Waals equation

text: It is of some historical interest to point out that Van der Waals, in his Nobel prize lecture, gave credit to Laplace for the argument that pressure is reduced proportional to the square of the density.


title: Van der Waals equation

text: The canonical partition function "Z" of an ideal gas consisting of "N = nN" identical (non-interacting) particles, is:


title: Van der Waals equation

text: with the usual definitions: "h" is the Planck constant, "m" the mass of a particle, "k" the Boltzmann constant and "T" the absolute temperature. In an ideal gas "z" is the partition function of a single particle in a container of volume "V". In order to derive the Van der Waals equation we assume now that each particle moves independently in an average potential field offered by the other particles. The averaging over the particles is easy because we will assume that the particle density of the Van der Waals fluid is homogeneous.


title: Van der Waals equation

text: "r" is the distance between the centers of the spheres and "d" is the distance where the hard spheres touch each other (twice the Van der Waals radius). The depth of the Van der Waals well is formula_55.


title: Van der Waals equation

text: Because the particles are not coupled under the mean field Hamiltonian, the mean field approximation of the total partition function still factorizes,


title: Van der Waals equation

text: but the intermolecular potential necessitates two modifications to "z". First, because of the finite size of the particles, not all of "V" is available, but only "V − Nb"', where (just as in the conventional derivation above)


title: Van der Waals equation

text: exp[" - ϕ/2kT"] to take care of the average intermolecular potential. We divide here the potential by two because this interaction energy is shared between two particles. Thus


title: Van der Waals equation

text: where we assumed that in a shell of thickness d"r" there are "N/V" 4"π" "r""dr" particles. This is a mean field approximation; the position of the particles is averaged. In reality the density close to the particle is different than far away as can be described by a pair correlation function. Furthermore, it is neglected that the fluid is enclosed


title: Van der Waals equation

text: Below the critical temperature, the Van der Waals equation seems to predict qualitatively incorrect relationships. Unlike for ideal gases, the p-V isotherms oscillate with a relative minimum ("d") and a relative maximum ("e"). Any pressure between "p" and "p" appears to have 3 values for the volume, contradicting the experimental observation that two state variables completely determine a one-component system's state. Moreover, the isothermal compressibility is negative between "d" and "e" (equivalently formula_65), which cannot describe a system at equilibrium.


title: Van der Waals equation

text: To address these problems, James Clerk Maxwell replaced the isotherm between points "a" and "c" with a horizontal line positioned so that the areas of the two shaded regions would be equal (replacing the "a"-"d"-"b"-"e"-"c") curve with a straight line from "a" to "c"); this portion of the isotherm corresponds to the liquid-vapor equilibrium. The regions of the isotherm from "a"–"d" and from "c"–"e" are interpreted as metastable states of super-heated liquid and super-cooled vapor, respectively. The equal area rule can be expressed as:


title: Van der Waals equation

text: where "p" is the vapor pressure (flat portion of the curve), "V" is the volume of the pure liquid phase at point "a" on the diagram, and "V" is the volume of the pure gas phase at point "c" on the diagram. A two-phase mixture at "p" will occupy a total volume between "V" and "V", as determined by Maxwell's lever rule.


title: Van der Waals equation

text: Maxwell justified the rule based on the fact that the area on a "pV" diagram corresponds to mechanical work, saying that work done on the system in going from "c" to "b" should equal work released on going from "a" to "b". This is because the change in free energy "A"("T","V") equals the work done during a reversible process, and, as a state variable, the free energy must be path-independent. In particular, the value of "A" at point "b" should be the same regardless of whether the path taken is from left or right across the horizontal isobar, or follows the original Van der Waals isotherm.


title: Van der Waals equation

text: This derivation is not entirely rigorous, since it requires a reversible path through a region of thermodynamic instability, while "b" is unstable. Nevertheless, modern derivations from chemical potential reach the same conclusion, and it remains a necessary modification to the Van der Waals and to any other analytic equation of state.


title: Van der Waals equation

text: The Maxwell equal area rule can also be derived from an assumption of equal chemical potential "μ" of coexisting liquid and vapour phases. On the isotherm shown in the above plot, points "a" and "c" are the only pair of points which fulfill the equilibrium condition of having equal pressure, temperature and chemical potential. It follows that systems with volumes intermediate between these two points will consist of a mixture of the pure liquid and gas with specific volumes equal to the pure liquid and gas phases at points "a" and "c".


title: Van der Waals equation

text: The Van der Waals equation may be solved for "V" and "V" as functions of the temperature and the vapor pressure "p". Since:


title: Van der Waals equation

text: Since the gas and liquid volumes are functions of "p" and "T" only, this equation is then solved numerically to obtain "p" as a function of temperature (and number of particles "N"), which may then be used to determine the gas and liquid volumes.


title: Van der Waals equation

text: in the accompanying figure. One sees that the two locii meet at the critical point (1,1,1) smoothly. An isotherm of the Van der Waals fluid taken at "T " = 0.90 is also shown where the intersections of the isotherm with the loci illustrate the construct's requirement that the two areas (red and blue, shown) are equal.


title: Van der Waals equation

text: We reiterate that the extensive volume "V"  is related to the volume per particle "v=V/N"  where "N = nN"  is the number of particles in the system.


title: Van der Waals equation

text: The equation of state does not give us all the thermodynamic parameters of the system. We can take the equation for the Helmholtz energy "A"


title: Van der Waals equation

text: Where Φ is an undetermined constant, which may be taken from the Sackur–Tetrode equation for an ideal gas to be:


title: Van der Waals equation

text: This equation expresses "A"  in terms of its natural variables "V"  and "T" , and therefore gives us all thermodynamic information about the system. The mechanical equation of state was already derived above


title: Van der Waals equation

text: Similar equations can be written for the other thermodynamic potential and the chemical potential, but expressing any potential as a function of pressure "p"  will require the solution of a third-order polynomial, which yields a complicated expression. Therefore, expressing the enthalpy and the Gibbs energy as functions of their natural variables will be complicated.


title: Van der Waals equation

text: Although the material constant "a" and "b" in the usual form of the Van der Waals equation differs for every single fluid considered, the equation can be recast into an invariant form applicable to "all" fluids.


title: Van der Waals equation

text: Defining the following reduced variables ("f", "f" are the reduced and critical variable versions of "f", respectively),


title: Van der Waals equation

text: The first form of the Van der Waals equation of state given above can be recast in the following reduced form:


title: Van der Waals equation

text: This equation is "invariant" for all fluids; that is, the same reduced form equation of state applies, no matter what "a" and "b" may be for the particular fluid.