There are good reasons for society to have evolved from value stored in the weighable gold of Florentine ducats to the digital codes of bank databases.
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Such extra mass, in theory, could be weighed in the same way as any other type of rest mass, even though individually photons have no rest mass. The property that trapped energy in any form adds weighable mass to systems that have no net momentum is one of the characteristic and notable consequences of relativity. It has no counterpart in classical Newtonian physics, in which radiation, light, heat, and kinetic energy never exhibit weighable mass.
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Tetrabutylammonium tribromide, abbreviated to TBATB, is a pale orange solid with the formula [N(C4H9)4]Br3. It is a salt of the lipophilic tetrabutylammonium cation and the linear tribromide anion. The salt is sometimes used as a reagent used in organic synthesis as a conveniently weighable, solid source of bromine.
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Because Grignard reagents are so sensitive to moisture and oxygen, many methods have been developed to test the quality of a batch. Typical tests involve titrations with weighable, anhydrous protic reagents, e.g. menthol in the presence of a color-indicator. The interaction of the Grignard reagent with phenanthroline or 2,2'-bipyridine causes a color change.
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7, 312). This is a good example of the type of > non sequitur that is abundant in this book, in that weighability and > pourability are not criteria that come to mind when evaluating theories, nor > is autoevolution itself especially weighable or pourable.Dyer, Betsey > Dexter; Schuster, Peter; Holm, Nils G. (1989). A. Lima-de-Faria, Evolution > Without Selection Form and Function by Autoevolution.
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Research is limited by its short half-life, which prevents the creation of weighable quantities. A visible piece of astatine would immediately vaporize itself because of the heat generated by its intense radioactivity. It remains to be seen if, with sufficient cooling, a macroscopic quantity of astatine could be deposited as a thin film. Astatine is usually classified as either a nonmetal or a metalloid; metal formation has also been predicted.
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However, the element directly above element 98 in the periodic table, dysprosium, has a name that simply means "hard to get at" so the researchers decided to set aside the informal naming convention. They added that "the best we can do is to point out [that] ... searchers a century ago found it difficult to get to California." Weighable quantities of californium were first produced by the irradiation of plutonium targets at the Materials Testing Reactor at the National Reactor Testing Station in eastern Idaho; and these findings were reported in 1954. The high spontaneous fission rate of californium-252 was observed in these samples.
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Plutonium could be produced through the irradiation of uranium-238 in a nuclear reactor, although no one had yet built one. This was not the Manhattan Project's chemists' problem; theirs was to develop a large-scale process for separating fission products, some of which were dangerously radioactive; uranium, the chemistry of which little was known; and plutonium, the chemistry of which almost nothing at all was known and which at first was only available in microscopic quantities. Four methods of separation were pursued. Seaborg performed the first successful separation of a weighable quantity of plutonium in August 1942, using a process involving lanthanum fluoride.
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However, after the discovery of the long-lived 237Np isotope in 1942 by Glenn Seaborg and Arthur Wahl, forming weighable amounts of neptunium became a realistic endeavor. Its half-life was initially determined to be about 3 million years (later revised to 2.144 million years), confirming the predictions of Nishina and Kimura of a very long half-life. Early research into the element was somewhat limited because most of the nuclear physicists and chemists in the United States at the time were focused on the massive effort to research the properties of plutonium as part of the Manhattan Project. Research into the element did continue as a minor part of the project and the first bulk sample of neptunium was isolated in 1944.
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A combination of radiochemistry and radiation chemistry is used to study nuclear reactions such as fission and fusion. Some early evidence for nuclear fission was the formation of a short-lived radioisotope of barium which was isolated from neutron irradiated uranium (139Ba, with a half-life of 83 minutes and 140Ba, with a half-life of 12.8 days, are major fission products of uranium). At the time, it was thought that this was a new radium isotope, as it was then standard radiochemical practice to use a barium sulfate carrier precipitate to assist in the isolation of radium. More recently, a combination of radiochemical methods and nuclear physics has been used to try to make new 'superheavy' elements; it is thought that islands of relative stability exist where the nuclides have half-lives of years, thus enabling weighable amounts of the new elements to be isolated.
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