Types of copper

The characteristics of a powder that determine its apparent density are rather complex, but some general statements with respect to powder variables and their effect on the density of the loose powder can be made. (/) The smaller the particles, the greater the specific surface area of the powder. This increases the friction between the particles and lowers the apparent density but enhances the rate of sintering. (2) Powders having very irregular-shaped particles are usually characterized by a lower apparent density than more regular or spherical ones. This is shown in Table 4 for three different types of copper powders having identical particle size distribution but different particle shape. These data illustrate the decisive influence of particle shape on apparent density. (J) In any mixture of coarse and fine powder particles, an optimum mixture results in maximum apparent density. This optimum mixture is reached when the fine particles fill the voids between the coarse particles. 

Converting. The most common type of copper converter is the Peirce-Smith converter, developed in the United States in 1906. The converter has changed Httie since that time. 

Copper. Copper plating, used as a final finish in some appHcations, is primarily employed as an undercoat for other deposits. Of the several types of copper baths, the two most popular in the United States are the acid sulfate and the cyanide baths. Acid copper caimot be used directly over... 

The various grades of copper available do not differ to any marked extent in their corrosion resistance, and a choice is usually based on other grounds. Subsequent references to the corrosion behaviour of copper may therefore be taken to apply broadly to all types of copper. 

Tracy, Thompson and Freeman exposed specimens of 11 different grades of copper in the form of sheet and wire to rural, marine and industrial atmospheres in the USA for periods up to 20 years. The differences in the behaviour of the materials were small and of little, if any, practical significance. Very similar results for various types of copper were found by... 

No. of types of copper No. of different alloys No. of sites Period of exposure (years) A verage rates of attack from weight losses (mm/y x 10 ) ... 

Several extensive series of soil-corrosion tests have been carried out by the National Bureau of Standards in the United States, and the results have been summarised by Romanoflf. In one series two types of copper and ten copper alloys were exposed in fourteen different soils for periods up to 14 years. The results for the copper specimens are summarised in Table 4.12. 

Another type of copper reagent was prepared from RZnI/CuCN, and this was shown to couple with alkenyl halides." ... 

Table 2. Types of copper dithiocarbamato complexes found so far ) ...

Van Niekerk, J.N. and Schoening, RR.L. 1953. A new type of copper complex as found in the crystal structure of cupric acetate, Cu2(CH3C00)4x2H20. Acta Crystallographica 6 227-232. 

De Marco [285] evaluated three different types of copper (II) ion-selective electrodes. The copper sulfide electrode was found to be oxidised, whereas the copper selenide and copper sulfide electrodes were found to have chloride ion interference at copper (II) activities exceeding 10 8 M. 

Binding of anions, cations, and organic substrates. In order to probe the roles of the different types of copper atoms and the nature of the electron transfer pathways between them, a variety of complexes of hCP with inhibitors of oxidase activity and... 

Table 5.2 contains data about selected copper enzymes from the references noted. It should be understood that enzymes from different sources—that is, azurin from Alcaligenes denitrificans versus Pseudomonas aeruginosa, fungal versus tree laccase, or arthropodan versus molluscan hemocyanin—will differ from each other to various degrees. Azurins have similar tertiary structures—in contrast to arthropodan and molluscan hemocyanins, whose tertiary and quaternary structures show large deviations. Most copper enzymes contain one type of copper center, but laccase, ascorbate oxidase, and ceruloplasmin contain Type I, Type II, and Type III centers. For a more complete and specific listing of copper enzyme properties, see, for instance, the review article by Solomon et al.4... 

The NO/NO+ and NO/NO- self-exchange rates are quite slow (42). Therefore, the kinetics of nitric oxide electron transfer reactions are strongly affected by transition metal complexes, particularly by those that are labile and redox active which can serve to promote these reactions. Although iron is the most important metal target for nitric oxide in mammalian biology, other metal centers might also react with NO. For example, both cobalt (in the form of cobalamin) (43,44) and copper (in the form of different types of copper proteins) (45) have been identified as potential NO targets. In addition, a substantial fraction of the bacterial nitrite reductases (which catalyze reduction of NO2 to NO) are copper enzymes (46). The interactions of NO with such metal centers continue to be rich for further exploration. 

As mentioned earlier in this chapter, the choice of collector is very much dependent on the type of copper minerals, as well as the type of gangue minerals present in the natural ore. If the ore contains siliceous gangue minerals, then various fatty acid modifications can be used as the principal collector in plant practice. Ores containing carbonaceous and dolo-mitic gangue minerals, where sulphidization method is used, xanthate collector is used as... 

The basic reagent scheme used in the concentrators varies and is dependent on the type of copper minerals present in the ore, and the mineral composition of the gangue. The reagent scheme used in the three main concentrators treating this ore type is presented in Table 19.11. 

The correlation between rheological data and the most frequent particle diameter Dmf has been studied on a dispersion of the gamma modification of Pigment Violet 19 and various types of copper phthalocyanine blue in an offset vehicle on... 

Knowledge of the most important types of copper phthalocyanine pigments is useful for the understanding of the processes concepts underlying pigment manufacture. Heading the list are the a- and [i-modil i cations of unsubstituted Copper Phthalocyanine Blue (Sec. 3.1.2.3). The a-modification exhibits an unstabilized and a stabilized form as to change of crystal modification. 

The a- and (i-types of Copper Phthalocyanine Blue reign supreme among commercially available phthalocyanine pigments. There is also an increasing amount of interest in the phase-stabilized form of the a-crystal modification. Both modifications are also supplied as flocculation resistant types. 

P.B.15 1, like other types of Copper Phthalocyanine, find extensive use in the spin dyeing of polypropylene, polyester, polyamide, secondary acetate, viscose rayon, and spun rayon. In these, as in other media, P.B.15 1 is very lightfast, and its textile fastness properties are almost entirely if not entirely satisfactory. 

The prints exhibit excellent application properties. They are, for instance, entirely fast to organic solvents, soap, alkali, and acids. They are also fast to sterilization. Metal deco prints demonstrate very good heat stability. The products withstand exposure to 200°C for 10 minutes or to 180°C for 30 minutes. Although not quite as fast to heat as halogenated types of Copper Phthalocyanine Green, P.B.15 3 is thus somewhat more heat stable than stabilized a-Copper Phthalocyanine Blue. 

P.B.16 is used especially to produce metallic finishes. Incorporated in acrylate resin systems for this purpose, the pigment is weatherfaster than types of Copper... 

In copper-containing proteins, three types of copper, classified on the basis of their visible, UV and EPR spectra, as originally proposed by one of the pioneers of copper biochemistry, Bo Malmstrom, are found. Types 1 and 2 have one copper atom, which has an intense blue colour in Type 1 and is almost colourless in Type 2 whereas Type 3 has an EPR-silent dicopper centre. More details of the three types are as follows ... 

Previous literature on formation of various types of copper acetylides is discussed and the mechanism of their formation is examined, with experimental detail. Whenever a copper or copper-rich alloy is likely to come into contact with atmospheres containing [1] ammonia, water vapour and acetylene, or [2] lime-sludge, water vapour and acetylene, or a combination of these two, there is the probability of acetylide formation and danger of explosion. The action is aided by the presence... 

This type of copper cluster has not previously been observed in any metalloprotein. Despite the fact that the structure of this important crystal has been solved, much remains for scientists to learn about the physical, spectroscopic, and chemical properties of the Cuz catalytic center. For example, we could ask ourselves questions such as these First of all, are there copper-copper bonds present in the cluster Second, why are four copper ions needed for a two-electron reduction (78 words aim for 62 words)... 

V. Proteins That Bind More Than One Type of Copper. 178... 

Blue or Type 1 copper centres comprise one of the three types of copper found in biological systems. The distinctive properties of this class of protein is an intense... 

Fig. 5 Relationship between the amount of graft polymers and Mn of free polymers. The graft polymerization was carried out under various conditions on silicon wafer (squares), silica particles with varying diameter (d = 12, 130, 290, 740, 1550 nm) (circles), and silica monolith with 50-nm mesopores (triangles). Two types of immobilized initiators, 2 and 5 (n = 6 and R" = CH3) in Fig. 2, two types of copper halides, CuBr and CnCl, and two types of ligands, spartein (Sp) and dipyridyl derivatives (4,4 -diheptyl-2,2 -dipyridyl (dHbipy) and 4,4 -dinonyl-2,2 -dipyridyl (dNbipy)), were used...

The blue oxidases contain these three types of copper together The stoichiometry is straightforward with laccase which contains one type-1 and one type-2 copper, and one type-3 dimeric copper site . One would expect two laccase-like sites in ascorbate oxidase and in ceruloplasmin, but the presence of respectively 3 and 1 and 1 and 3 type-1 and type-2 copper atoms has been deduced. Ceruloplasmin shows oxidase activities towards different substrates, like Fe (ferroxidase) and aromatic amines. It plays, moreover, an active role in the transport of copper With the proper precautions against the action of proteinases it can be isolated as a single polypeptide chain... 

A reduction to hydrogen peroxide is obtained with enzymes with one copper atom of type-2 (Table 1). A reduction to water requires enzymes with a dimeric site, with the three types of copper or with a four-metal center (2 heme, 2 Cu) (Table 1). 

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