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Graham's law

Graham's law of effusion was formulated by Scottish physical chemist Thomas Graham in 1848. Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles; this formula can be written as: Rate 1 Rate 2 = M 2 M 1,where: Rate1 is the rate of effusion for the first gas.. Rate2 is the rate of effusion for the second gas. M1 is the molar mass of gas 1 M2 is the molar mass of gas 2. Graham's law states that the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight. Thus, if the molecular weight of one gas is four times that of another, it would diffuse through a porous plug or escape through a small pinhole in a vessel at half the rate of the other. A complete theoretical explanation of Graham's law was provided years by the kinetic theory of gases. Graham's law provides a basis for separating isotopes by diffusion—a method that came to play a crucial role in the development of the atomic bomb.

Graham's law is most accurate for molecular effusion which involves the movement of one gas at a time through a hole. It is only approximate for diffusion of one gas in another or in air, as these processes involve the movement of more than one gas. In the same conditions of temperature and pressure, the molar mass is proportional to the mass density. Therefore, the rates of diffusion of different gases are inversely proportional to the square roots of their mass densities. R ∝ 1 d Let gas 1 be H2 and gas 2 be O2. Rate H 2 Rate O 2 = 32 2 = 16 = 4 Therefore, hydrogen molecules effuse four times faster than those of oxygen. Using the formula of gaseous diffusion, the ratio of rate of diffusion of NH3 and HCl gas was obtained as 1.46 +_ 0.01. Graham's Law can be used to find the approximate molecular weight of a gas if one gas is a known species, if there is a specific ratio between the rates of two gases; the equation can be solved for the unknown molecular weight. M 2 = M 1 Rate 1 2 Rate 2 2 Graham's law was the basis for separating 235U from 238U found in natural uraninite during the Manhattan Project to build the first atomic bomb.

The United States government built a gaseous diffusion plant in Clinton, Tennessee at the cost of $100 million. In this plant, uranium from uranium ore was first converted to uranium hexafluoride and forced to diffuse through porous barriers, each time becoming a little more enriched in the lighter 235U isotope. Graham's research on the diffusion of gases was triggered by his reading about the observation of German chemist Johann Döbereiner that hydrogen gas diffused out of a small crack in a glass bottle faster than the surrounding air diffused in to replace it. Graham measured the rate of diffusion of gases through plaster plugs, through fine tubes, through small orifices. In this way he slowed down the process, he first stated in 1831 that the rate of effusion of a gas is inversely proportional to the square root of its density, in 1848 showed that this rate is inversely proportional to the square root of the molar mass. Graham went on to study the diffusion of substances in solution and in the process made the discovery that some apparent solutions are suspensions of particles too large to pass through a parchment filter.

He termed these materials colloids, a term that has come to denote an important class of finely divided materials. Around the time Graham did his work, the concept of molecular weight was being established through the measurements of gases. Daniel Bernoulli suggested in 1738 in his book Hydrodynamica that heat increases in proportion to the velocity, thus kinetic energy, of gas particles. Italian physicist Amedeo Avogadro suggested in 1811 that equal volumes of different gases contain equal numbers of molecules. Thus, the relative molecular weights of two gases are equal to the ratio of weights of equal volumes of the gases. Avogadro's insight together with other studies of gas behaviour provided a basis for theoretical work by Scottish physicist James Clerk Maxwell to explain the properties of gases as collections of small particles moving through empty space; the greatest success of the kinetic theory of gases, as it came to be called, was the discovery that for gases, the temperature as measured on the Kelvin temperature scale is directly proportional to the average kinetic energy of the gas molecules.

Graham's law for diffusion could thus be understood as a consequence of the molecular kinetic energies being equal at the same temperature. The rationale of the above can be summed up as follows: Kinetic energy of each type o

ISO 3166-1

ISO 3166-1 is part of the ISO 3166 standard published by the International Organization for Standardization, defines codes for the names of countries, dependent territories, special areas of geographical interest. The official name of the standard is Codes for the representation of names of countries and their subdivisions – Part 1: Country codes, it defines three sets of country codes: ISO 3166-1 alpha-2 – two-letter country codes which are the most used of the three, used most prominently for the Internet's country code top-level domains. ISO 3166-1 alpha-3 – three-letter country codes which allow a better visual association between the codes and the country names than the alpha-2 codes. ISO 3166-1 numeric – three-digit country codes which are identical to those developed and maintained by the United Nations Statistics Division, with the advantage of script independence, hence useful for people or systems using non-Latin scripts; the alphabetic country codes were first included in ISO 3166 in 1974, the numeric country codes were first included in 1981.

The country codes have been published as ISO 3166-1 since 1997, when ISO 3166 was expanded into three parts, with ISO 3166-2 defining codes for subdivisions and ISO 3166-3 defining codes for former countries. As a used international standard, ISO 3166-1 is implemented in other standards and used by international organizations to allow facilitation of the exchange of goods and information. However, it is not the only standard for country codes. Other country codes used by many international organizations are or incompatible with ISO 3166-1, although some of them correspond to ISO 3166-1 codes. 249 countries, territories, or areas of geographical interest are assigned official codes in ISO 3166-1. According to the ISO 3166 Maintenance Agency, the only way to enter a new country name into ISO 3166-1 is to have it registered in one of the following two sources: United Nations Terminology Bulletin Country Names, or Country and Region Codes for Statistical Use of the UN Statistics Division. To be listed in the bulletin Country Names, a country must be at least one of the following: A member state of the United Nations A member of one of its specialized agencies A party to the Statute of the International Court of JusticeThe list of names in Country and Region Codes for Statistical Use of the UN Statistics Division is based on the bulletin Country Names and other UN sources.

Once a country name or territory name appears in either of these two sources, it will be added to ISO 3166-1 by default. The ISO 3166/MA may reserve code elements for other entities that do not qualify for inclusion based on the above criteria. For example, because the European Union is not a country, it is not formally included in ISO 3166-1, but for practical reasons, the ISO 3166/MA has "reserved the two-letter combination EU for the purpose of identifying the European Union within the framework of ISO 3166-1". ISO 3166-1 is published in both English and French. Since the second edition of ISO 3166-1, the following columns are included for each entry: Country Name – English short name English short name lower case English full name Alpha-2 code Alpha-3 code Numeric code Remarks Independent Additional information: Administrative language alpha-2 code element Additional information: Administrative language alpha-3 code element Additional information: Local short name The country names used in ISO 3166-1 are taken from the two UN sources mentioned above.

Some country names used by the UN, accordingly by ISO, are subject to dispute: The codes are chosen, according to the ISO 3166/MA, "to reflect the significant, unique component of the country name in order to allow a visual association between country name and country code". For this reason, common components of country names like "Republic", "Kingdom", "United", "Federal" or "Democratic" are not used for deriving the code elements; as a consequence, for example, the United Kingdom is assigned the alpha-2 code GB rather than UK, based on its official name "United Kingdom of Great Britain and Northern Ireland". Some codes are chosen based on the native names of the countries. For example, Germany is assigned the alpha-2 code DE, based on its native name "Deutschland"; the following is a complete ISO 3166-1 encoding list of the countries which are assigned official codes. It is listed in alphabetical order by the country's English short name used by the ISO 3166/MA. Note: Each country's alpha-2 code is linked to more information about the assignment of its code elements.

Besides the assigned codes, code elements may be expanded by using either reserved codes or user-assigned codes. Reserved code elements are codes which have become obsolete, or are required in order to enable a particular user application of the standard but do not qualify for inclusion in ISO 3166-1. To avoid transitional application problems and to aid users who require specific additional code elements for the functioning of their coding systems, the ISO 3166/MA, when justified, reserves these codes which it undertakes not to use for other than specified purposes during a limited or indeterminate period of time. Codes are reserved for former countries, overseas territories, international organizations, special nationality status; the reserved alpha-2 and alpha-3 codes can be divided into the following four categories: Alpha-2: exceptional reservations, transitional reservations, indeterminate reservations, codes agreed not to use Alpha-3: exceptional reservations


A freedman or freedwoman is a enslaved person, released from slavery by legal means. Enslaved people were freed either by manumission or emancipation. A fugitive slave is a person. Rome differed from Greek city-states in allowing freed slaves to become plebeian citizens; the act of freeing a slave was called manumissio, from manus, "hand", missio, the act of releasing. After manumission, a slave who had belonged to a Roman citizen enjoyed not only passive freedom from ownership, but active political freedom, including the right to vote. A slave who had acquired libertas was known as a libertus in relation to his former master, called his or her patron; as a social class, freed slaves were liberti, though Latin texts used the terms libertus and libertini interchangeably. Libertini were not entitled to hold public office or state priesthoods, nor could they achieve legitimate senatorial rank. During the early Empire, freedmen held key positions in the government bureaucracy, so much so that Hadrian limited their participation by law.

Any future children of a freedman would be born free, with full rights of citizenship. The Claudian Civil Service set a precedent whereby freedmen could be used as civil servants in the Roman bureaucracy. In addition, Claudius passed legislation concerning slaves, including a law stating that sick slaves abandoned by their owners became freedmen if they recovered; the emperor was criticized for using freedmen in the Imperial Courts. Some freedmen became quite wealthy; the brothers who owned House of the Vettii, one of the biggest and most magnificent houses in Pompeii, are thought to have been freedmen. A freedman who became rich and influential might still be looked down on by the traditional aristocracy as a vulgar nouveau riche. Trimalchio, a character in the Satyricon of Petronius, is a caricature of such a freedman. For centuries Arab slave traders took and transported an estimated 10 to 15 million sub-Saharan Africans to slavery in North Africa and the Middle East, they enslaved Europeans from coastal areas and the Balkans.

The slaves were predominately women. Many Arabs took women slaves as concubines in their harems. In the patrilineal Arab societies, the mixed-race children of concubines and Arab men were considered free, they were given inheritance rights related to their fathers' property. No studies have been done of the influence of African-Arab descendants in the societies. In the United States, the terms "freedmen" and "freedwomen" refer chiefly to former slaves emancipated during and after the American Civil War by the Emancipation Proclamation and the 13th Amendment. Slaves freed before the war were referred to as "Free Negroes" or free blacks. In addition, there was a population of black Americans born free; the great majority of families of free people of color recorded in the US census in the Upper South in the first two decades after the Revolutionary War have been found to have descended from unions between white women and black men in colonial Virginia. According to laws in the slave colonies, children were born into the social status of their mothers.

Such free families of color tended to migrate to the frontier of Virginia and other Upper South colonies, west into Kentucky, West Virginia and Tennessee with white neighbors. In addition, during the first two decades after the Revolution, slaveholders freed thousands of slaves in the Upper South, inspired by revolutionary ideals. Most northern states abolished some on a gradual basis. In Louisiana and other areas of the former New France, free people of color were classified in French as gens de couleur libres, they were born to black or mixed-race mothers and white fathers of ethnic French or other European ancestry. The fathers sometimes freed their children and sexual partners, leading to the growth of the community of Creoles of color, or free people of color. New Orleans had the largest community of free people of color, well-established before the US acquired Louisiana; the French and Spanish colonial rulers had given the free people of color more rights than most free blacks had in the American South.

In addition, there were sizable communities of free people of color in French Caribbean colonies, such as Saint-Domingue and Guadeloupe. Due to the violence of the Haitian Revolution, many free people of color, who were part of the revolution, fled the island as refugees after being attacked by slave rebels in the north of the island; some went first to Cuba, from where they immigrated to New Orleans in 1808 and 1809 after being expelled when Napoleon invaded Spanish territory in Europe. Many brought slaves with them, their numbers strengthened the French-speaking community of enslaved black peoples, as well as the free people of color. Other refugees from Saint-Domingue settled in Charleston and New York. Although the Emancipation Proclamation of 1863 declared all slaves in states not under the control of the Union to be free, it did not end slavery as an institution. Abolition of all slavery was achieved with the ratification of the Thirteenth Amendment to the United States Constitution; the Fourteenth Amendment gave ex-slaves full citizen

Richard C. Bush

Richard C. Bush III is an American expert on China affairs, he is the director of Center for Northeast Asian Policy Studies of the Brookings Institution and a Senior Fellow of Foreign Policy. Richard Bush began his career in 1977 with the China Council of The Asia Society. In 1983 he became a staff consultant on the House Foreign Affairs Committee’s Subcommittee on Asian and Pacific Affairs. In 1993 he moved up to the full committee, where he worked on Asia issues and served as liaison with Democratic members. In 1995, he became national intelligence officer for East Asia and a member of the National Intelligence Council, which coordinates the analytic work of the intelligence community, he left the NIC in 1997 to become head of the American Institute in Taiwan. He has served in the executive and legislative branches of U. S. government for 19 years, including those of National Intelligence Officer for East Asia and Chairman of the board of the American Institute in Taiwan, is still active in observing international affairs in East Asia.

Richard Bush received his undergraduate education at Lawrence University in Wisconsin. He did his graduate work in political science at Columbia University, getting an M. A. in 1973 and his Ph. D. in 1978. His thesis in political science concentrated on studies about China-Taiwan relations, U. S.-China relations, the Korean peninsula and Japan’s security. He published At Cross Purposes: U. S.-Taiwan Relations since 1942 in 2004, Untying the Knot in 2006, A War Like No Other: The Truth About China's Challenge to America in 2007, The Perils of Proximity: China-Japan Security Relations in 2010.. His latest work, Hong Kong in the Shadow of China: Living With the Leviathan was published in 2016. Bush, Richard C.. At Cross Purposes: U. S. - Taiwan Relations Since 1942. Armonk, New York: M. E. Sharpe. ISBN 0-7656-1372-7. Retrieved 23 December 2014. Bush, Richard C.. Untying the Knot: Making Peace in the Taiwan Strait. Washington, D. C.: The Brookings Institution. ISBN 978-0-8157-1288-6. Retrieved 23 December 2014.

Bush, Richard C.. A War Like No Other: The Truth About China's Challenge to America. Hoboken, New Jersey: John Wiley & Sons. ISBN 978-0-471-98677-5. Retrieved 23 December 2014. Bush, Richard C.. The Perils of Proximity: China-Japan Security Relations. Washington, D. C.: The Brookings Institution. ISBN 978-0-8157-0474-4. Retrieved 23 December 2014. Bush, Richard C.. Uncharted Strait: The Future of China-Taiwan Relations. Washington, D. C.: The Brookings Institution. ISBN 978-0-8157-2384-4. Retrieved 23 December 2014. Bush, Richard C.. One China Policy Primer. Washington, D. C.: The Brookings Institution. Retrieved 3 March 2017

Company (Justin Bieber song)

"Company" is a song by Canadian singer Justin Bieber from his fourth studio album Purpose. Written by Bieber, Poo Bear, James Abrahart, Andreas Schuller, Thomas Troelsen, James Wong and Leroy Clampitt, the song was produced by Axident, Big Taste and co-produced by Boyd, it was released to American rhythmic contemporary and contemporary hit radio stations on March 8, 2016 as the album's fourth and final single. It is an electropop and R&B song, with bass guitar and percussion in its instrumentation. Lyrically, "Company" talks about looking forward to getting to know someone attractive, but sets some healthy boundaries for doing so; as an album track, it reached the top-forty in the majority of the countries. When it was released as a single, the song managed to reach the top-forty in Australia and peaked at number 53 in the United States. Bieber performed the track on the 3rd iHeartRadio Music Awards and 2016 Billboard Music Awards, as well as on his Purpose World Tour. Two music videos were made for the song: the video, part of the "Purpose: The Movement" narrative, released on November 14, 2015, the official music video released on June 8, 2016.

While working on the album, Bieber invited his personal friend, American songwriter and producer Poo Bear, to collaborate on the record – both had worked on Bieber's second compilation album, Journals, in 2013. They collaborated on the record, writing a lot of songs, until his label tried to set up writing camps for Bieber, but he declined and kept on working with Boyd; as declared by Boyd during an interview for The Fader, "We're just thinking about making sure that it's not negative, but uplifting. The music that talks about his relationships, it's feel-good music. It's nothing. We're so in tune with each other, that it's easy to know what we're both gonna love, what he would love to sing. We worked hard on this project. We honest with ourselves." While being asked if there were any songs that he was excited about, Boyd claimed that one of them was "Company". In early February 2016, it was reported that Def Jam Recordings, Bieber's label, was eyeing to release "Company" as the follow-up to his previous successful single, "Love Yourself".

The label's promotional team informally tipped radio professionals the week of February 16, 2016, as reported by Headline Planet. A week Billboard confirmed that "Company" would serve as the album's fourth single, that it would impact both rhythmic contemporary and contemporary hit radio stations on March 8, 2016. On April 7, 2016, a remix by The Knocks was posted on the band's SoundCloud account, as they announced they would be the opening act on selected dates of Bieber's Purpose World Tour. "Company" was written by Justin Bieber, Poo Bear, James Abrahart, Andreas Schuller, Thomas Troelsen, James Wong and Leroy Clampitt. It was produced by Axident and Big Taste, co-produced by Boyd. According to the sheet music published at by Alfred Publishing Company, the song is composed in the key of E minor with a moderately R&B groove of 95 beats per minute. Bieber's vocals range from the note of D4 to B5, it is an electropop and R&B song, with bass guitar and percussion in its instrumentation.

The song has "a mellow, calm yet sparkly mood, noted to be reminiscent from his previous album, Journals. Lyrically, "Company" talks about seeking surface-level companionship on the dance floor. During the track, the protagonist is looking forward to getting to know someone attractive, but sets some healthy boundaries for doing so, which can be seen in the lyrics: "You ain't gotta be my lover for you to call me baby/ … Just wanna have a conversation." Patrick Ryan of USA Today called it a "pulsing come-hither." Amy Davidson of Digital Spy opined that "'Company' is what happens when Justin Bieber feels like a non-committal hook-up during a stop on his gruelling tour and writes a cool R&B serenade to convince you it's a good idea." Sheldon Pearce of Complex called it "a strutting electropop tune project emotional availability." Brennan Carley of Spin named it "the triumphant Grecian sunrise, the mid-album highlight." For Al Horner of NME, "the funk-laced'Company' is a hit-in-waiting," while Megan Downing of MTV UK labelled it "an easy-listening track oozing with coolness."

Casey Lewis of Teen Vogue thought that the song "sounds like the comeback track Usher wishes he had, to say that it's good, just nothing like the quartet of singles he released while hyping this album." Commercially, "Company" charted after the release of Purpose in a number of countries. In the United States, the song debuted at number 53 on the Billboard Hot 100, along with other sixteen tracks of the album. After being released as a single, "Company" re-entered at number 89, it peaked once again at number 53, it was certified gold by the Recording Industry Association of America. In New Zealand, the song debuted at number 30, after the album's release, reaching the top-twenty the following week, at number 18, which became its peak position; the song re-entered at number 36, when it was released as a single, but only went to reach number 27 as its highest position. In Australia, the song entered at number 41, on the week of April 3, 2016, peaking two weeks at number 34, becoming Bieber's first single to miss the top-twenty since "Hold Tight".

Two music videos were made for the song. The first was released along with the "Purpose: The Movement" project on November 14, 2015; as stated by Bustle's Claire Landsbaum, " follows a group of women who meet a group of guys in a diner. One member of each party leaves the restaurant and does a sexy couple's dance in front of a lit-up Har


Titley is a village and civil parish in Herefordshire, England. It lies on the B4355 between Presteigne. In the 2001 census the parish had a population of 167; the name, recorded in the Domesday Book as Titelege, is Old English and means "woodland clearing of a man called Titta". The village of Titley has been occupied for over a thousand years and there is evidence of a pre-conquest priory in the village dedicated to an obscure Welsh saint and subordinate to the abbey of Tiron in France. Titley lies at the junction of two drovers' roads and a local pub was, at one time, used for the weighing of wool. Titley's parish church, dedicated to Saint Peter was rebuilt in 1869; the Stagg Inn, known as The Balance until 1833, became in 2001 the first pub in the United Kingdom to be awarded a Michelin Star. Eywood House was built just west of the village in 1705. A landscaped park was laid out around the house, an existing kettle lake, Titley Pool, was enlarged; the house was demolished in 1958. Titley Pool is now a nature reserve.

Titley village hall is situated directly behind The Stagg Inn and is available for hire, as well as being used by the parish council and other local organisations such as the WI, Scouts & Brownies and bowls clubs. A mile-long section of the former Leominster and Kington Railway was reopened in 2005. Known as The Kingfisher Line, the section is owned and is open to the public only by prior arrangement. Titley Village Hall website Media related to Titley at Wikimedia Commons