Hydrogen fluoride is a chemical compound with the chemical formula HF. This colorless gas or liquid is the principal industrial source of fluorine as an aqueous solution called hydrofluoric acid, it is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers. HF is used in the petrochemical industry as a component of superacids. Hydrogen fluoride boils near room temperature, much higher than other hydrogen halides. Hydrogen fluoride is a dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture; the gas can cause blindness by rapid destruction of the corneas. In 1771 Carl Wilhelm Scheele prepared the aqueous solution, hydrofluoric acid in large quantities, although hydrofluoric acid had been known in the glass industry before then. French chemist Edmond Frémy is credited with discovering anhydrous hydrogen fluoride while trying to isolate fluorine. Although a diatomic molecule, HF forms strong intermolecular hydrogen bonds.
Solid HF consists of zig-zag chains of HF molecules. The HF molecules, with a short H–F bond of 95 pm, are linked to neighboring molecules by intermolecular H–F distances of 155 pm. Liquid HF consists of chains of HF molecules, but the chains are shorter, consisting on average of only five or six molecules. Hydrogen fluoride does not boil until 20 °C in contrast to the heavier hydrogen halides, which boil between −85 °C and −35 °C; this hydrogen bonding between HF molecules gives rise to high viscosity in the liquid phase and lower than expected pressure in the gas phase. HF is miscible with water. In contrast, the other hydrogen halides exhibit limiting solubilities in water. Hydrogen fluoride form a monohydrate HF. H2O (−40 °C, 44 °C above the melting point of pure HF. Aqueous solutions of HF are called hydrofluoric acid; when dilute, hydrofluoric acid is a weak acid, unlike the other hydrohalic acids. However concentrated solutions are strong acids due to the formation of hydrogen-bonded ion pairs.
In liquid anhydrous HF, self-ionization occurs: 3 HF ⇌ H2F+ + HF−2which forms an acidic solution. HF reacts with Lewis acids to give superacids. A Hammett acidity function of −21 is obtained with antimony pentafluoride. Hydrogen fluoride is produced by the action of sulfuric acid on pure grades of the mineral fluorite: CaF2 + H2SO4 → 2 HF + CaSO4About 20% of manufactured HF is a byproduct of fertilizer production, which generates hexafluorosilicic acid; this acid can be degraded to release HF thermally and by hydrolysis: H2SiF6 → 2 HF + SiF4 SiF4 + 2 H2O → 4 HF + SiO2 In general, the anhydrous compound hydrogen fluoride is more common industrially than its aqueous solution, hydrofluoric acid. Its main uses, on a tonnage basis, are as a precursor to organofluorine compounds and a precursor to cryolite for the electrolysis of aluminium. HF reacts with chlorocarbons to give fluorocarbons. An important application of this reaction is the production of tetrafluoroethylene, precursor to Teflon. Chloroform is fluorinated by HF to produce chlorodifluoromethane: CHCl3 + 2 HF → CHClF2 + 2 HClPyrolysis of chlorodifluoromethane yields TFE.
HF is a reactive solvent in the electrochemical fluorination of organic compounds. In this approach, HF is oxidized in the presence of a hydrocarbon and the fluorine replaces C–H bonds with C–F bonds. Perfluorinated carboxylic acids and sulfonic acids are produced in this way.1,1-Difluoroethane is produced by adding HF to acetylene using mercury as a catalyst. HC≡CH + 2 HF → CH3CHF2The intermediate in this process is vinyl fluoride or fluoroethylene, the monomeric precursor to polyvinyl fluoride; the electrowinning of aluminium relies on the electrolysis of aluminium fluoride in molten cryolite. Several kilograms of HF are consumed per ton of Al produced. Other metal fluorides are produced using HF, including uranium hexafluoride. HF is the precursor to elemental fluorine, F2, by electrolysis of a solution of HF and potassium bifluoride; the potassium bifluoride is needed. Several million kilograms of F2 are produced annually. HF serves, it is used in the majority of the installed linear alkyl benzene production facilities in the world.
The process involves dehydrogenation of n-paraffins to olefins, subsequent reaction with benzene using HF as catalyst. For example, in oil refineries "alkylate", a component of high-octane petrol, is generated in alkylation units, which combine C3 and C4 olefins and iso-butane. Hydrogen fluoride is an excellent solvent. Reflecting the ability of HF to participate in hydrogen bonding proteins and carbohydrates dissolve in HF and can be recovered from it. In contrast, most non-fluoride inorganic chemicals react with HF rather than dissolving. Upon contact with moisture, including tissue, hydrogen fluoride converts to hydrofluoric acid, corrosive and toxic. Exposure requires immediate medical attention, it can cause blindness by rapid destruction of the corneas. Breathing in hydrogen fluoride at high levels or in combination with skin contact can cause death from an irregular heartbeat or from fluid buildup in the lungs. "ATSDR – Fluorides, Hydrogen Fluoride, Fluorine". Retrieved September 30, 2019 CDC - NIOSH Pocket Guide to Chemical Hazards Toxics Use Reduction Institute - Hydrogen Fluoride Fact Sheet
Edward Leathley Armitage was an Irish born English cricketer, the son of John Leathley Armitage and his wife Annie Jessie, née Nicholas. A right-handed batsman and right-arm medium pace bowler, he played first-class cricket for several teams between 1919 and 1933. Armitage made his first-class debut in August 1919, for Hampshire in a County Championship match against Essex, playing three more County Championship matches that month, he played just once against Leicestershire. In 1921 he played twice against Oxford University and Kent. In 1924, after a first-class match for the Army against Cambridge University, he played two matches for the Marylebone Cricket Club against his native Ireland, in Dublin and Belfast, he played for the Army against Oxford University and the Royal Navy in 1925, a season in which he played his final first-class match for Hampshire, against Worcestershire. In 1926 he played for Malaya against Hong Kong and for the Straits Settlements against the Federated Malay States.
He returned to English cricket in 1929, playing for the Free Foresters against Cambridge University, for the Army against the RAF and the Royal Navy, for the MCC against Oxford University and Ireland. That year he played a first-class match in India as part of the Bombay Quadrangular tournament, his final first-class matches were in 1931 for the MCC against Oxford University, in 1933 for the Viceroy's XI against Roshanara Club in Delhi. On 28 April 1945 in London he married Lady Katherine Jane Elizabeth Manley, née Carnegie, daughter of the 10th Earl of Northesk, as her second husband, they had no children. Armitage was the first cousin twice removed of Edward Armitage and Thomas Rhodes Armitage, second cousin once removed of Robert Armitage and third cousin of Robert Selby Armitage
Chinese painting is one of the oldest continuous artistic traditions in the world. Painting in the traditional style is known today in Chinese as guóhuà, meaning "national" or "native painting", as opposed to Western styles of art which became popular in China in the 20th century. Traditional painting involves the same techniques as calligraphy and is done with a brush dipped in black ink or coloured pigments; as with calligraphy, the most popular materials on which paintings are made are silk. The finished work can be mounted on scrolls, such as hanging handscrolls. Traditional painting can be done on album sheets, lacquerware, folding screens, other media; the two main techniques in Chinese painting are: Gongbi, meaning "meticulous", uses detailed brushstrokes that delimit details precisely. It is highly coloured and depicts figural or narrative subjects, it is practised by artists working for the royal court or in independent workshops. Ink and wash painting, in Chinese shuǐ-mò loosely termed watercolour or brush painting, known as "literati painting", as it was one of the "Four Arts" of the Chinese Scholar-official class.
In theory this was an art practiced by gentlemen, a distinction that begins to be made in writings on art from the Song dynasty, though in fact the careers of leading exponents could benefit considerably. This style is referred to as "xieyi" or freehand style. Landscape painting was regarded as the highest form of Chinese painting, still is; the time from the Five Dynasties period to the Northern Song period is known as the "Great age of Chinese landscape". In the north, artists such as Jing Hao, Li Cheng, Fan Kuan, Guo Xi painted pictures of towering mountains, using strong black lines, ink wash, sharp, dotted brushstrokes to suggest rough stone. In the south, Dong Yuan and other artists painted the rolling hills and rivers of their native countryside in peaceful scenes done with softer, rubbed brushwork; these two kinds of scenes and techniques became the classical styles of Chinese landscape painting. Chinese painting and calligraphy distinguish themselves from other cultures' arts by emphasis on motion and change with dynamic life.
The practice is traditionally first learned by rote, in which the master shows the "right way" to draw items. The apprentice must copy these items and continuously until the movements become instinctive. In contemporary times, debate emerged on the limits of this copyist tradition within modern art scenes where innovation is the rule. Changing lifestyles and colors are influencing new waves of masters; the earliest paintings were not representational but ornamental. Early pottery was painted with spirals, dots, or animals, it was only during the Eastern Zhou. In imperial times and calligraphy in China were among the most appreciated arts in the court and they were practiced by amateurs—aristocrats and scholar-officials—who had the leisure time necessary to perfect the technique and sensibility necessary for great brushwork. Calligraphy and painting were thought to be the purest forms of art; the implements were the brush pen made of animal hair, black inks made from pine soot and animal glue. In ancient times, writing, as well as painting, was done on silk.
However, after the invention of paper in the 1st century AD, silk was replaced by the new and cheaper material. Original writings by famous calligraphers have been valued throughout China's history and are mounted on scrolls and hung on walls in the same way that paintings are. Artists from the Han to the Tang dynasties painted the human figure. Much of what we know of early Chinese figure painting comes from burial sites, where paintings were preserved on silk banners, lacquered objects, tomb walls. Many early tomb paintings were meant to help their souls to get to paradise. Others illustrated the teachings of the Chinese philosopher Confucius or showed scenes of daily life. During the Six Dynasties period, people began to appreciate painting for its own beauty and to write about art. From this time we begin to learn about individual artists, such as Gu Kaizhi; when these artists illustrated Confucian moral themes – such as the proper behavior of a wife to her husband or of children to their parents – they tried to make the figures graceful.
The "Six principles of Chinese painting" were established by Xie He, a writer, art historian and critic in 5th century China, in "Six points to consider when judging a painting", taken from the preface to his book "The Record of the Classification of Old Painters". Keep in mind that this was written circa 550 CE and refers to "old" and "ancient" practices; the six elements that define a painting are: "Spirit Resonance", or vitality, which refers to the flow of energy that encompasses theme and artist. Xie He said that without Spirit Resonance, there was no need to look further. "Bone Method", or the way of using the brush, refers not only to texture and brush stroke, but to the close link between handwriting and personality. In his day, the art of calligraphy was inseparable from painting. "Correspondence to the Object", or the depicting of form, which would include shape and line. "Suitability to Type", or the application of color, including layers and tone. "Division and Planning", or placing and arrangemen
Nabilah Lubis is an Indonesian philologist, writer and lecturer. Nabilah is an Egyptian woman, married by a Batak Mandailing man from Medan named Burhanuddin Umar Lubis, so she changed her last name to Nabilah Lubis. After Lubis completed her doctoral education at the Syarif Hidayatullah State Islamic Institute in 1992, she became the first female doctorate at IAIN Jakarta. Two years in 1994, professor Quraish Shihab as chancellor of IAIN Jakarta appointed her as Dean of the Faculty of Adab and Humanities. Lubis retired from her position as Professor at the Faculty of Adab and Humanities at UIN Jakarta in 2007, she is the Expert Council of the Muslimat Nahdlatul Ulama for the period 2016–2021 with Sinta Nuriyah Wahid and eight other people. Nabilah Lubis in libraries
Paul Duffield is a former professional Australian rules footballer who played for the Fremantle Football Club in the Australian Football League. He plays as a half back flanker and began his football career at South Fremantle Football Club in the West Australian Football League. Selected in the rookie draft at the 2003 AFL Draft, he is a medium-sized defender who spent the 2004 and 2005 seasons on the rookie list, playing for South Fremantle; the nephew of The West Australian newspaper sports journalist Mark Duffield, he was a member of South Fremantle's 2005 premiership team. His father and uncles Brett and Mark, were all successful country footballers. Due to the AFL rules restricting rookies to a maximum of two years before being elevated or delisted, Duffield was delisted at the end of the 2005 season. However, Fremantle reselected him in the 2005 rookie draft. Duffield made his AFL pre-season debut against Collingwood in the quarter-final and played in the semi final loss to Geelong. On 19 April 2006, it was announced that Duffield had been elevated to the senior list as a replacement for Daniel Haines, who had injured his achilles tendon the previous weekend playing for Peel Thunder.
Duffield made his debut a week against St Kilda in the controversial game at Aurora Stadium in Launceston, Tasmania. At Fremantle he was allocated guernsey number 41. After playing in the last six games in 2008, Duffield cemented his spot in the Fremantle team in 2009, only missing one game, he finished fourth in the club's best and fairest award. In 2010 he was selected in the Australian international rules football team for the 2010 International Rules Series against Ireland. Duffield announced his retirement at the conclusion of the 2015 season. Duffield is an old boy of Aquinas College and was School Captain in his final year, 2002. Paul Duffield's profile on the official website of the Fremantle Football Club Paul Duffield's playing statistics from AFL Tables WAFL statistics
Lieutenant Colonel Jevon Albert "Jeff" Nicklin OBE was a Canadian Army officer and football player. He fought during World War II and was one of the first Canadians to jump on D-Day, 6 June 1944, led the 1st Canadian Parachute Battalion in the Battle of the Bulge and when it jumped into German territory in Operation Varsity during the final stages of the war in March 1945. Nicklin was killed in action during the operation; the native of Winnipeg was born in the son of Percy Harold Nicklin and Eva Louise Nicklin. He played Canadian football as a back with the Winnipeg Blue Bombers from 1934 to 1940. In 1935, Winnipeg became the first Western team to capture the Grey Cup. While Nicklin was there, the club advanced to the Grey Cup twice more in 1937 and 1938, before losing in the finals. In 1939, Winnipeg returned to capture the 27th Grey Cup by defeating the Ottawa Rough Riders. Nicklin received Western all-star honours as an end in 1937 and 1938, as flying wing in 1939, he played in the Tea Bowl for the Canadian Army football team against American Army team at White City Stadium on February 13, 1944 in London, England.
Nicklin served in the Canadian Army during the Second World War, worked his way up through the ranks from private. In 1942, he deployed to Europe with the Royal Winnipeg Rifles. Nicklin received parachute training in the United States at Fort Benning and returned to Canada to establish the country's first parachute unit at Camp Shilo, Manitoba, he became the Commanding Officer of the 1st Canadian Parachute Battalion serving as part of the 3rd Parachute Brigade of the British 6th Airborne Division, just before November 1, 1944 and was promoted to lieutenant colonel on November 10, 1944. Nicklin was one of the first Canadians to jump on D-Day in June 1944 and one of the first to jump into Germany. On D-Day, June 6, 1944, he landed in the midst of a German position at Varaville, his parachute was ensnared on a rooftop, he received fire from German soldiers before he cut himself free and took cover. He rejoined his unit, was wounded by shrapnel, he was killed in action on March 24, 1945 During an airborne assault across the Rhine northwest of Wesel as part of Operation Varsity, Nicklin's parachute became tangled in a tall tree, as he attempted to free himself, he was shot and killed by German soldiers.
He is now buried in Groesbeek Canadian War Cemetery. He left Mary Eileen Nicklin, in Port Credit, Ontario. On July 12, 1945 it was announced that he had been appointed Officer of the Order of the British Empire, "in recognition of gallant and distinguished services in North-West Europe"; the original recommendation for the honour describes how he was able to "rectify certain aspects of the Battalion's life which were not satisfactory" and credited him with "the smooth working and unparalleled success which has met the inclusion of a Canadian Battalion in a British Brigade", the recommendation concludes, "throughout the present campaign his example of courageous leadership has been an example to all who have come into contact with him." The Jeff Nicklin Memorial Trophy for the Canadian Football League West Division's most valuable player is named in his honour. Nicklin was inducted into the Manitoba Sports Hall of Fame in 2004. Sportswriter Vince Leah placed Nicklin atop his list of all-time greatest Winnipeg players in A History of the Blue Bombers.