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Raney Nickel
Raney nickel , also called spongy nickel, is a fine-grained solid composed mostly of nickel derived from a nickel–aluminium alloy. Several grades are known, of which most are gray solids. Some are pyrophoric, but most are used as air-stable slurries. Raney nickel is used as a reagent and as a catalyst in organic chemistry. It was developed in 1926 by American engineer Murray Raney for the hydrogenation of vegetable oils. Raney Nickel is a registered trademark of W. R. Grace and Company. Other major producers are Evonik and Johnson Matthey. Preparation Alloy preparation The Ni–Al alloy is prepared by dissolving nickel in molten aluminium followed by cooling ("quenching"). Depending on the Ni:Al ratio, quenching produces a number of different phases. During the quenching procedure, small amounts of a third metal, such as zinc or chromium, are added to enhance the activity of the resulting catalyst. This third metal is called a "Promoter (catalysis), promoter". The promoter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel (as natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayerite
Gibbsite, Al(OH)3, is one of the mineral forms of aluminium hydroxide. It is often designated as γ-Al(OH)3 (but sometimes as α-Al(OH)3). It is also sometimes called hydrargillite (or hydrargyllite). Gibbsite is an important ore of aluminium in that it is one of three main phases that make up the rock bauxite. Gibbsite has three named structural polymorphs or polytypes: bayerite (designated often as α-Al(OH)3, but sometimes as β-Al(OH)3), '' doyleite'', and nordstrandite. Gibbsite can be monoclinic or triclinic, while bayerite is monoclinic. Doyleite and nordstrandite are triclinic forms. Structure The structure of gibbsite is interesting and analogous to the basic structure of the micas. The basic structure forms stacked sheets of linked octahedra. Each octahedron is composed of an aluminium ion bonded to six hydroxide groups, and each hydroxide group is shared by two aluminium octahedra. One third of the potential octahedral spaces are missing a central aluminium. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Teller
Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of the History of the Teller–Ulam design, Teller–Ulam design based on Stanisław Ulam's design. He had a volatile personality, and was "driven by his megaton ambitions, had a Messiah complex, messianic complex, and displayed autocratic behavior." A thermonuclear design he devised was an Alarm Clock model bomb with a yield of 1000 MT (1 GT of TNT) and he proposed delivering it by boat or submarine. It would be capable of incinerating a continent. Born in Austria-Hungary in 1908, Teller emigrated to the US in the 1930s, one of the many so-called The Martians (scientists), "Martians", a group of Hungarian scientist émigrés. He made numerous contributions to Nuclear physics, nuclear and molecular physics, spectroscopy, and Surface science, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Hugh Emmett
Paul Hugh Emmett (September 22, 1900 – April 22, 1985) was an American chemist best known for his pioneering work in the field of catalysis and for his work on the Manhattan Project during World War II. He spearheaded the research to separate isotopes of uranium and to develop a corrosive uranium gas. Emmett also made significant contributions to BET Theory which explains the relationship between surface area and gas adsorption. He served on the faculty of Johns Hopkins University for 23 years throughout his scientific career. Early life Paul Hugh Emmett was born on September 22, 1900, in Portland, Oregon to John Hugh Emmett (1864-1943) and Lavina Hutchins (1870-1941). Emmett's father was a railroad engineer. For a year in his early childhood, Emmett's family lived in a rail car while his mother worked as a cook for the rail company. Emmett attended Washington High School where he excelled in language and mathematics classes. Among his acquaintances in high school was Linus Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen Brunauer
Stephen Brunauer (February 12, 1903 – July 6, 1986) was an American research chemist, government scientist, and university teacher. He resigned from his position with the U.S. Navy during the McCarthy era, when he found it impossible to refute anonymous charges that he was disloyal to the U.S. Early years Stephen Brunauer was born István Brunauer on February 12, 1903, to a Jewish family in Budapest, Hungary. His father was blind and his mother worked as a seamstress. He emigrated to the United States in 1921 and attended City College of New York and Columbia University, majoring in English and chemistry. He received his A.B. from Columbia in 1925. He pursued graduate studies in chemistry and engineering, earning his master's degree in 1929 from George Washington University, where he was a student of Edward Teller, who later described his confidence in asserting his theories and challenging his teachers. While a student, he belonged briefly to the Young Workers' League, a Commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesh
Medical Subject Headings (MeSH) is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences. It serves as a thesaurus of index terms that facilitates searching. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed article database and by NLM's catalog of book holdings. MeSH is also used by ClinicalTrials.gov registry to classify which diseases are studied by trials registered in ClinicalTrials. MeSH was introduced in the 1960s, with the NLM's own index catalogue and the subject headings of the Quarterly Cumulative Index Medicus (1940 edition) as precursors. The yearly printed version of MeSH was discontinued in 2007; MeSH is now available only online. It can be browsed and downloaded free of charge through PubMed. Originally in English, MeSH has been translated into numerous other languages and allows retrieval of documents from different origins. Structure MeSH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Close-up Of Raney Nickel
A close-up or closeup in filmmaking, television production, still photography, and the comic strip medium is a type of shot that tightly frames a person or object. Close-ups are one of the standard shots used regularly with medium and long shots (cinematic techniques). Close-ups display the most detail, but they do not include the broader scene. Moving toward or away from a close-up is a common type of zooming. A close up is taken from head to neck, giving the viewer a detailed view of the subject's face. History Most early filmmakers, such as Thomas Edison, Auguste and Louis Lumière and Georges Méliès, tended not to use close-ups and preferred to frame their subjects in long shots, similar to the stage. Film historians disagree as to the filmmaker who first used a close-up. One of the best claims is for George Albert Smith in Hove, who used medium close-ups in films as early as 1898 and by 1900 was incorporating extreme close-ups in films such as ''As Seen Through a Tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raney Nickel
Raney nickel , also called spongy nickel, is a fine-grained solid composed mostly of nickel derived from a nickel–aluminium alloy. Several grades are known, of which most are gray solids. Some are pyrophoric, but most are used as air-stable slurries. Raney nickel is used as a reagent and as a catalyst in organic chemistry. It was developed in 1926 by American engineer Murray Raney for the hydrogenation of vegetable oils. Raney Nickel is a registered trademark of W. R. Grace and Company. Other major producers are Evonik and Johnson Matthey. Preparation Alloy preparation The Ni–Al alloy is prepared by dissolving nickel in molten aluminium followed by cooling ("quenching"). Depending on the Ni:Al ratio, quenching produces a number of different phases. During the quenching procedure, small amounts of a third metal, such as zinc or chromium, are added to enhance the activity of the resulting catalyst. This third metal is called a "Promoter (catalysis), promoter". The promoter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raney Nickel Phase Diagram
Raney is a surname, and may refer to: * Albert Raney Sr. (), developer of Mystic Caverns in Arkansas, United States * Catherine Raney (born 1980), American Olympic speed skater * Della H. Raney (1912–1987), African-American pioneering Army nurse *Doug Raney (1956–2016), American jazz guitarist; son of Jimmy Raney * George P. Raney (1845–1911), American politician and attorney, Chief Justice of the Florida Supreme Court *Jimmy Raney (1927–1995), American jazz guitarist * John H. Raney (1849–1928), American politician * John N. Raney (born 1947), American politician and businessman * Michele E. Raney (born 1951), American physician and first woman to over winter at an Antarctica inland station * Murray Raney (1885–1966), American mechanical engineer; inventor of Raney nickel * Paul Hartley Raney (1892–1917), Canadian fighter pilot killed in World War I *Reisha Raney, American business executive and engineer * Ribs Raney (1923–2003), American baseball pitcher * Robert J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degassed Water
Degassed water is water subjected to a process of degassing, which essentially consists in the removal of gas dissolved in the liquid. External links *Nature publication by Philip Ball * Journal of Physical Chemistry C
''The Journal of Physical Chemistry C'' publishes scientific articles reporting research on several subdisciplines of physical chemistry:
*Nanoparticles and nanostructures
*surfaces, interfaces, and catalysis
*Electron transport, optical and ele ... publicatio[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selective Leaching
In metallurgy, selective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type in some solid solution alloys, when in suitable conditions a component of the alloys is preferentially Leaching (metallurgy), leached from the initially homogenous material. The less noble metal, noble metal is removed from the alloy by a microscopic-scale galvanic corrosion mechanism. The most susceptible alloys are the ones containing metals with high distance between each other in the galvanic series, e.g. copper and zinc in brass. The elements most typically undergoing selective removal are zinc, aluminium, iron, cobalt, chromium, and others. Leaching of zinc The most common example is selective leaching of zinc from brass alloys containing more than 15% zinc (dezincification) in the presence of oxygen and moisture, e.g. from brass taps in chlorine-containing water. Dezincification has been studied since the 1860s, and the mechanism by which it oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
