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platinum group | A Wisdom Archive on platinum group | | platinum group A selection of articles related to platinum group | |
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platinum group
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| ARTICLES RELATED TO platinum group | | | |  platinum group: Encyclopedia II - Ultramafic to mafic layered intrusions - Causes of layeringThe causes of layering in large ultramafic intrusions include convection, thermal diffusion, assimilation of wall rocks and fractional crystallization.
The primary mechanism for forming cumulate layers is of course the accumulation of layers of mineral crystals on the floor or roof of the intrusion. Rarely, plagioclase is found in cumulate layers at the top of intrusions, having floated to the top of a much denser magma. Here it can form anorthosite layers.
Accumulation occurs as crystals are formed by fractional crystallisatio ...
See also:Ultramafic to mafic layered intrusions, Ultramafic to mafic layered intrusions - Intrusive behaviour and setting, Ultramafic to mafic layered intrusions - Intrusive Mechanisms, Ultramafic to mafic layered intrusions - Plume Magmatism, Ultramafic to mafic layered intrusions - Rift magmatism, Ultramafic to mafic layered intrusions - Causes of layering, Ultramafic to mafic layered intrusions - Examples Read more here: » Ultramafic to mafic layered intrusions: Encyclopedia II - Ultramafic to mafic layered intrusions - Causes of layering |
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| | | | | | platinum group: Encyclopedia II - Hydrogen economy - Examples Several domestic US automobile manufactures have committed to develop vehicles using hydrogen. (They had previously committed to producing electric vehicles in California, a program now defunct at their behest.) Critics argue this "commitment" is merely a ploy to sidestep current calls for increased efficiency in gasoline and diesel fuel powered vehicles.
Some hospitals have installed combined electrolyzer-storage-fuel cell units for local emergency power. These are advantageous for emergency use due to their low maintenance requirement and ease of location compa ...
See also:Hydrogen economy, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Envisioned centralized hydrogen sources, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Examples |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - Storage Storage is the main technological problem of a viable hydrogen economy. Some attention has been given to the role of hydrogen to provide grid energy storage for unpredictable energy sources, like wind power. The primary difficulty with using hydrogen for grid energy storage is that converting power to hydrogen and back is not cheap.
Hydrocarbons are stored extensively at the point of use, be it in the gasoline tanks of automobiles or propane tanks hung on the side of barbecue grills. Hydrogen, in comparison, is quite expensive to stor ...
See also:Hydrogen economy, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Envisioned centralized hydrogen sources, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Storage |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - Environmental concerns 48% of hydrogen gas is created through the natural gas steam reforming/water gas shift reaction method, outlined above. This creates carbon dioxide (CO2), a greenhouse gas, as a byproduct. This is usually released into the atmosphere, although there has also been some research into interning it underground or undersea.
Recently, there have also been some concerns over possible problems related to hydrogen gas leakage. Molecular hydrogen leaks slowly from most containment vessels. It has been hypothesized that if significant ...
See also:Hydrogen economy, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Envisioned centralized hydrogen sources, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Environmental concerns |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - Consumption
Hydrogen economy - Chemical feed.
Hydrogen is used in chemical reactions - the Haber process and hydrocracking - as described in "The present" above.
Hydrogen economy - Energy source.
The underlying premise of a hydrogen economy is that fuel cells will replace internal combustion engines and turbines as the primary way to convert chemical power into motive and electrical power. The reason to expect this changeover is that fuel cells, being electrochemical, can be more efficient than heat engines. Currently, fuel cells are very expensive, but there is ...
See also:Hydrogen economy, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Envisioned centralized hydrogen sources, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Consumption |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - Production The production and distribution of hydrogen for the purpose of transportation is being tested in limited markets around the world, particularly in Iceland, Germany, California, Japan and Canada. There are several processes which can yield hydrogen via water splitting using various energy sources at different efficiencies and costs. As of 2005, 48% of hydrogen production (for industrial processes) is from natural gas, 30% is from oil, 18% is from coal, and 4% is from electrolysis.
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See also:Hydrogen economy, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Envisioned centralized hydrogen sources, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Production |
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| | | | | | platinum group: Encyclopedia II - Fountain pen - Filling Mechanisms The earliest fountain pens were mostly eyedropper fillers - that is, the pen was essentially an empty reservoir which one would fill with an eyedropper. This was a relatively awkward and messy process, though the absence of complicated mechanisms meant that an eyedropper-filler could hold much more ink than could a self-filling pen of comparable size. As a result, eyedropper-filling pens constitute only a tiny fraction of pens made today.
After the eyedropper-filler era came the first generation of mass produced self-fillers, almost all using a rubber sac to hold the ink. By various mechanisms, the sac could be compressed an ...
See also:Fountain pen, Fountain pen - History, Fountain pen - Using fountain pens, Fountain pen - Nibs, Fountain pen - Filling Mechanisms, Fountain pen - Cartridges, Fountain pen - Fountain pens as works of art, Fountain pen - List of fountain pen manufacturers, Fountain pen - List of famous fountain pen inks Read more here: » Fountain pen: Encyclopedia II - Fountain pen - Filling Mechanisms |
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| | | | | platinum group: Encyclopedia II - Fountain pen - Cartridges Most European fountain pen brands (for example Caran d'Ache, Faber-Castell, Dupont, Montegrappa, Stipula, Yard-O-Led, Pelikan, Waterman, Montblanc, Monteverde, Delta and Rotring) and some pen brands of other continents (for example Bexley, Retro51, Tombow and Acura) use so called "international cartridges" (AKA "european cartridges" or "standard cartridges" or "universal cartridges"), in short or long sizes, or both. It is to some extent a standard, so international cartridges of any manufacturer can be used in most fountain pens that accept ...
See also:Fountain pen, Fountain pen - History, Fountain pen - Using fountain pens, Fountain pen - Nibs, Fountain pen - Filling Mechanisms, Fountain pen - Cartridges, Fountain pen - Fountain pens as works of art, Fountain pen - List of fountain pen manufacturers, Fountain pen - List of famous fountain pen inks Read more here: » Fountain pen: Encyclopedia II - Fountain pen - Cartridges |
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| | | | | platinum group: Encyclopedia II - Fountain pen - Fountain pens as works of art Fountain pens are often prized as works of art. Ornate pens are sometimes made of precious metals and jewels; others are inlaid with lacquer designs in a process known as maki-e. An avid community of pen enthusiasts collect and use antique and modern pens and also collect and exchange information about old and modern inks, ink bottles, and inkwells. Collectors often tend to prize being able to actually use the ...
See also:Fountain pen, Fountain pen - History, Fountain pen - Using fountain pens, Fountain pen - Nibs, Fountain pen - Filling Mechanisms, Fountain pen - Cartridges, Fountain pen - Fountain pens as works of art, Fountain pen - List of fountain pen manufacturers, Fountain pen - List of famous fountain pen inks Read more here: » Fountain pen: Encyclopedia II - Fountain pen - Fountain pens as works of art |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - The present Hydrogen production is a large and growing industry. Globally, about 50 million metric tons of hydrogen were produced in 2004; the growth rate is about 10% per year. The energy in the current flow corresponds to about 200 gigawatts. Within the U.S., production was about 11 million metric tons, or 48 GW (10.8% of the average U.S. total electric production of 442 GW in 2003). Because hydrogen storage and transport are so expensive, most hydrogen is currently produced locally, and used immediately, generally by the same company producing it. As of 2005, the economic value of all h ...
See also:Hydrogen economy, Hydrogen economy - The present, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - The present |
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| | | | | platinum group: Encyclopedia II - Fountain pen - Nibs The nib of the fountain pen is usually made of stainless steel or gold. Gold nibs are tipped with a hard, wear-resistant alloy that typically utilizes metals from the platinum group. Tipping material is often called "iridium", even though hardly any penmakers still use that metal in their tipping alloys. Steel nibs may also have harder tips; those without steel points will wear more rapidly due to abrasion by the paper. The nib will adjust itself more readily to the user's style ...
See also:Fountain pen, Fountain pen - History, Fountain pen - Using fountain pens, Fountain pen - Nibs, Fountain pen - Filling Mechanisms, Fountain pen - Cartridges, Fountain pen - Fountain pens as works of art, Fountain pen - List of fountain pen manufacturers, Fountain pen - List of famous fountain pen inks Read more here: » Fountain pen: Encyclopedia II - Fountain pen - Nibs |
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| | | | | platinum group: Encyclopedia II - Fountain pen - Using fountain pens Together with the mass-manufactured pencil and the introduction of cheap wood-based paper, the fountain pen was responsible for a major transformation in writing and in the nature of paperwork during the 19th century. They gave birth to the precursor of the modern office, which would only come about at the end of the 19th century and the beginning of the 20th with the gradual introduction of the typewriter and early duplicating machines.
The fountain pen, and, to a lesser extent, the pencil, replaced the relatively hard-to-use combina ...
See also:Fountain pen, Fountain pen - History, Fountain pen - Using fountain pens, Fountain pen - Nibs, Fountain pen - Filling Mechanisms, Fountain pen - Cartridges, Fountain pen - Fountain pens as works of art, Fountain pen - List of fountain pen manufacturers, Fountain pen - List of famous fountain pen inks Read more here: » Fountain pen: Encyclopedia II - Fountain pen - Using fountain pens |
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| | | | | platinum group: Encyclopedia II - Abundance of the chemical elements - Abundance of elements in the Universe Hydrogen is the most abundant element in the known Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are orders of magnitude less common.
Both helium-3 and helium-4 were produced in the Big Bang. Additional helium is produced by the fusion of hydrogen inside stellar cores, via a process called the proton-proton chain.
Hydrogen and helium are estimated to make up roughly 80% and 20% of all the m ...
See also:Abundance of the chemical elements, Abundance of the chemical elements - Abundance of elements in the Universe, Abundance of the chemical elements - Abundance of elements in the Solar System, Abundance of the chemical elements - Abundance of elements in Earth, Abundance of the chemical elements - Abundance of elements in Earth's crust, Abundance of the chemical elements - Ocean, Abundance of the chemical elements - Atmosphere, Abundance of the chemical elements - Organisms, Abundance of the chemical elements - Human body Read more here: » Abundance of the chemical elements: Encyclopedia II - Abundance of the chemical elements - Abundance of elements in the Universe |
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| | | | | platinum group: Encyclopedia II - Abundance of the chemical elements - Abundance of elements in the Solar System The Solar System was created from the remnants of previous stellar systems that went supernova, and is hence, relative to the rest of the universe, richer in heavier elements.
Population I stars contain significant amounts of elements heavier than helium ("metals", in the terminology of astronomers). These heavy elements were produced by earlier generations of stars and spread by supernova explosions ...
See also:Abundance of the chemical elements, Abundance of the chemical elements - Abundance of elements in the Universe, Abundance of the chemical elements - Abundance of elements in the Solar System, Abundance of the chemical elements - Abundance of elements in Earth, Abundance of the chemical elements - Abundance of elements in Earth's crust, Abundance of the chemical elements - Ocean, Abundance of the chemical elements - Atmosphere, Abundance of the chemical elements - Organisms, Abundance of the chemical elements - Human body Read more here: » Abundance of the chemical elements: Encyclopedia II - Abundance of the chemical elements - Abundance of elements in the Solar System |
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| | | | | | platinum group: Encyclopedia II - Hydrogen economy - The short-term future The large market and sharply rising prices have also stimulated great interest in alternate, cheaper means of hydrogen production. One particular method that has gained considerable commercial interest and U.S. government funding is high-temperature thermochemical electrolysis of water (H2O). Some prototype nuclear reactors operate at 850 to 1000 degrees Celsius, considerably hotter than existing commercial plants. Thermochemical electrolysis of water at these temperatures converts more of the initial heat energy into chemical ene ...
See also:Hydrogen economy, Hydrogen economy - The present, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - The short-term future |
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| | | | | platinum group: Encyclopedia II - Hydrogen economy - Rationale Electricity has revolutionized the quality of human life since the late 19th century by enabling easier use of available energy sources. Inventions such as the dynamo and electric lighting sparked its growth on direct current. Later the alternator and alternating current enabled electric power transmission over long distances in a grand scale.
Currently, grid load balancing is done by varying the output of generators. However, electricity is hard to store efficiently for future use. The most cost-efficient and widespread system for la ...
See also:Hydrogen economy, Hydrogen economy - The present, Hydrogen economy - The short-term future, Hydrogen economy - Rationale, Hydrogen economy - Production, Hydrogen economy - Fossil fuels, Hydrogen economy - Electrolysis, Hydrogen economy - Thermochemical production, Hydrogen economy - Other methods, Hydrogen economy - Storage, Hydrogen economy - Ammonia storage, Hydrogen economy - Metal hydrides, Hydrogen economy - Synthesized hydrocarbons, Hydrogen economy - Other methods, Hydrogen economy - Transportation, Hydrogen economy - Environmental concerns, Hydrogen economy - Consumption, Hydrogen economy - Chemical feed, Hydrogen economy - Energy source, Hydrogen economy - Problems, Hydrogen economy - Examples Read more here: » Hydrogen economy: Encyclopedia II - Hydrogen economy - Rationale |
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| | | | | | platinum group: Encyclopedia II - Palladium - History Palladium was discovered by William Hyde Wollaston in 1803. This element was named by Wollaston in 1804 after the asteroid Pallas, which was discovered two years earlier.
Wollaston found element 46 in crude platinum ore from South America. He did this by dissolving the ore in aqua regia, neutralizing the solution with sodium hydroxide, NaOH, precipitating platinum as ammonium chloroplatinate through treatment with ammonium chloride, NH4Cl, and then adding mercuric cyanide to form the compound palladium cyanide. Finally, he heated the resulting compound ...
See also:Palladium, Palladium - Notable characteristics, Palladium - Applications, Palladium - History, Palladium - Occurrence, Palladium - Isotopes Read more here: » Palladium: Encyclopedia II - Palladium - History |
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