Metals scarce

Remaining terms to right of the bracket relate to properties to be measured within the matrix. The factor/is adjusted from 0 to 1 in relationship to the purpose of testing. A low value of/is indicated for scarce elements such as precious metals in electronic-source scrap. Moisture content has a high/value. The factor g is adjusted from 0 to... 

Copper is an essential trace metal for all living beings. However, although copper is indispensable for many physiological functions of human organism, the presence of excess amount of copper in the body may be toxic. One possible source of copper in human body that is scarcely investigated is dental materials. 

Metal-reducing bacteria, such as those that convert ferric to ferrous ion, have been suggested as an accelerant for steel corrosion in oxygenated waters, lb date, evidence of these bacteria influencing corrosion in industrial systems is scarce. 

One must consider, too, the cost of the materials themselves. Some of the metals used in conventional nickel alloys - such as hafnium - are hideously expensive (at UK 100,000 tonne or US 150,000 tonne ) and extremely scarce and the use of greater and greater quantities of exotic materials in an attempt to improve the creep properties will drive the cost of blades up. But expensive though it is, the cost of the... 

No fewer than 14 pure metals have densities se4.5 Mg (see Table 10.1). Of these, titanium, aluminium and magnesium are in common use as structural materials. Beryllium is difficult to work and is toxic, but it is used in moderate quantities for heat shields and structural members in rockets. Lithium is used as an alloying element in aluminium to lower its density and save weight on airframes. Yttrium has an excellent set of properties and, although scarce, may eventually find applications in the nuclear-powered aircraft project. But the majority are unsuitable for structural use because they are chemically reactive or have low melting points." ... 

Tautomeric rearrangements of transition-metal complexes with azole ligands are relatively scarce. The fluxional behavior of the rhodium complex 43 with a neutral 3,5-dimethylpyrazole was explained as the result of rapid processes of metallotropy and prototropy occurring simultaneously (Scheme 24) [74JOM(C)51],... 

Nontransition metal cyclopentadienyl derivatives of pyrrole are quite scarce (99CRV969). The derivatives M(2,5-C4H2 Bu2N)2 (M = Sn, Pb) were studied [92AG(E)778 92JCS(CC)760]. 

Spar-metall, n. scarce metal, -mlttel, n. Biol. 

Trustworthy thermodynamic data for metal solutions have been very scarce until recently,25 and even now they are accumulating only slowly because of the severe experimental difficulties associated with their measurement. Thermodynamic activities of the component of a metallic solution may be measured by high-temperature galvanic cells,44 by the measurement of the vapor pressure of the individual components, or by equilibration of the metal system with a mixture of gases able to interact with one of the components in the metal.26 Usually, the activity of only one of the components in a binary metallic solution can be directly measured the activity of the other is calculated via the Gibbs-Duhem equation if the activity of the first has been measured over a sufficiently extensive range of composition. 

The 1,3-dipolar cycloadditions are a powerful kind of reaction for the preparation of functionalised five-membered heterocycles [42]. In the field of Fischer carbene complexes, the a,/ -unsaturated derivatives have been scarcely used in cyclo additions with 1,3-dipoles in contrast with other types of cyclo additions [43]. These complexes have low energy LUMOs, due to the electron-acceptor character of the pentacarbonyl metal fragment, and hence, they react with electron-rich dipoles with high energy HOMOs. 

Passivation is defined as the state where even though a metal electrode fulfills the thermodynamic condition for dissolution (solution composition, electrode potential, etc.), a corrosive reaction scarcely proceeds. 

Once a passive film is formed on a metal surface, as long as the electrode potential remains in the passive potential region, the surface is stable, i.e., scarcely dissolved. However, if there are film-destructive anions like chloride ions in solution, the passive film is locally broken, so that local dissolution of the metal substrate proceeds at the same place. 

This is the most extensively, as well as intensively, studied type of the decarbonylation. Nevertheless, kinetic data are scarce. Conversion of metal acyls to their respective alkyls has been investigated for two systems RCOMn(CO), 37, 50, 51) and XCH2COIr(PPh3)2Cl2 (X = Ph or a substituted Ph group) 160). 

Studies of the electrodeposition of mercury chalcogenides are scarce, primarily because of the difference in electrochemical potentials needed to deposit mercury and the chalcogens. Mercury is a noble metal the standard redox potential for the... 

S of the vein-type deposits hosted by sedimentary rocks of the basement are low (less than 0%c), reflecting low of country rocks. However, they are scarce in number. 5 S of the base metal vein-type deposits and Kuroko deposits are relatively high (average value +4%c to 4-5%o) and most probably influenced by sulfate sulfur of seawater... 

A lot of research has been published on hydroformylation of alkenes, but the vast majority of the effort has been focused on the chemistry of various metal-ligand systems. Quantitative kinetic studies including modeling of rates and selectivities are much more scarce. In this work, we present the approach to modeling of hydroformylation kinetics and gas-solubility. Hydroformylation of 1-butene with a rhodium-based catalyst was selected as a case study. 

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