Bronze, density

Iron, cobalt, and nickel catalyze this reaction. The rate depends on temperature and sodium concentration. At —33.5°C, 0.251 kg sodium is soluble in 1 kg ammonia. Concentrated solutions of sodium in ammonia separate into two Hquid phases when cooled below the consolute temperature of —41.6°C. The compositions of the phases depend on the temperature. At the peak of the conjugate solutions curve, the composition is 4.15 atom % sodium. The density decreases with increasing concentration of sodium. Thus, in the two-phase region the dilute bottom phase, low in sodium concentration, has a deep-blue color the light top phase, high in sodium concentration, has a metallic bronze appearance (9—13). 

Diphosphate tungsten bronzes (DTB) Cs Hg (P 04)4(W03)gai e chai ge-density wave (CDW) conductors. The framework of Cs contains columns of corner-sharing WO octahedra internked through P O group. Properties of Cs can be tuned via out-of-... 

A centrifuge with a phosphor bronze basket, 380 mm in diameter, is to be run at 67 Hz with a 75 mm layer of liquid of density 1200 kg/m3 in the basket. What thickness of walls are required in the basket The density of phosphor bronze is 8900 kg/m3 and the maximum safe stress for phosphor bronze is 87.6 MN/m2. 

Besides magnetic perturbations and electron-lattice interactions, there are other instabilities in solids which have to be considered. For example, one-dimensional solids cannot be metallic since a periodic lattice distortion (Peierls distortion) destroys the Fermi surface in such a system. The perturbation of the electron states results in charge-density waves (CDW), involving a periodicity in electron density in phase with the lattice distortion. Blue molybdenum bronzes, K0.3M0O3, show such features (see Section 4.9 for details). In two- or three-dimensional solids, however, one observes Fermi surface nesting due to the presence of parallel Fermi surface planes perturbed by periodic lattice distortions. Certain molybdenum bronzes exhibit this behaviour. 

The M-NM transition has been a topic of interest from the days of Sir Humphry Davy when sodium and potassium were discovered till then only high-density elements such as Au, Ag and Cu with lustre and other related properties were known to be metallic. A variety of materials exhibit a transition from the nonmetallic to the metallic state because of a change in crystal structure, composition, temperature or pressure. While the majority of elements in nature are metallic, some of the elements which are ordinarily nonmetals become metallic on application of pressure or on melting accordingly, silicon is metallic in the liquid state and nonmetallic in the solid state. Metals such as Cs and Hg become nonmetallic when expanded to low densities at high temperatures. Solutions of alkali metals in liquid ammonia become metallic when the concentration of the alkali metal is sufficiently high. Alkali metal tungsten bronzes... 

The bronze solutions have the following characteristics (i) a bronze color with a definite metallic luster (2) very low densities (3) conductivities in the range of metals and (4) magnetic susceptibilities similar to those of pure metals. All of these properties are consistent with a model describing the solution as a dilute metai or an alloy in which the electrons behave essentially as in a metal, but the metal atoms have been moved apart (compared with the pure metal) by interspersed molecules of ammonia. 

Dense soda ash with bulk density 60 lb/cuft is to be conveyed a distance of 100 ft and elevated 12 ft. The material is class II-X with a factor F = 0.7. The bearings are self-lubricated bronze and the drive is V-belt with rj = 0.93. The size, speed, and power will be selected for a rate of 15 tons/hr. 

Compound (CHg Tel.CHgTelg6 (Vernon s j8-iodide).7—A filtered solution of the foregoing mixed anhydride is treated with hydriodic acid, the precipitate dissolved in acetone and reprecipitated by the addition of chloroform. Glistening crystals result, which are either deep purplish-red or bronzed greenish-black. Each crystal gives a reddish-purple streak, and the purple powder decomposes between 80° and 85° C. It is almost insoluble in chloroform and most non-hydroxvlie solvents. The crystals are monoclinic, the parameters being a b c =0 5465 1 0 4222 jS =76° 52. The density is 3 305 at 14° C.8... 

If using bronze anodes, Sn should be less than 10% and anode current density <1 A/dm2. 

If a solution containing approximately 4 mole percent sodium in ammonia is cooled below -42°C (231 K) a remarkable liquid-liquid phase separation occurs (33, 155). The solution physically separates into two distinct layers—a low-density, bronze metallic phase that floats out on top of a more dense, less concentrated dark-blue phase. The first experimental observation of this striking phenomenon in sodium-ammonia solutions was made by Kraus (109, 110) in 1907 more recent studies have mapped out the phase coexistence curves for a variety of alkali and alkaline earth metals in liquid ammonia, and these are delineated and discussed elsewhere (164). 

Mixtures of barium and sodium tungstates in the molten state give, with a current density of about 4 5 amps, per dm.2 at a pressure of 1 6 volts, bronzes which correspond to the following formulae —... 

The core of the bullet can be made from a variety of materials lead is by far the most common because of its high density and the fact that it is cheap, readily obtained, and easy to fabricate. But copper, brass, bronze, aluminum, steel (sometimes hardened by heat treatment), depleted uranium, zinc, iron, tungsten, rubber, and various plastics may also be encountered. (When most of the fissile radioactive isotopes of uranium are removed from natural uranium, the residue is called depleted uranium. Depleted uranium is 67% denser than lead, and it is an ideal bullet material and is very effective in an armor-piercing role, both in small arms and larger munitions components. Because of its residual radioactivity its use is controversial.) Bullets with a lead core and a copper alloy jacket are by far the most common. 

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