Metallation, competitive

This review is structured as follows. In the next section we present the theory for adsorbates that remain in quasi-equilibrium throughout the desorption process, in which case a few macroscopic variables, namely the partial coverages 0, and their rate equations are needed. We introduce the lattice gas model and discuss results ranging from non-interacting adsorbates to systems with multiple interactions, treated essentially exactly with the transfer matrix method, in Sec. II. Examples of the accuracy possible in the modehng of experimental data using this theory, from our own work, are presented for such diverse systems as multilayers of alkali metals on metals, competitive desorption of tellurium from tungsten, and dissociative... 

Since the metals can be considered as the limiting reactants, the effects of metal-metal competition for the ligands can be neglected. Thus, speciation calculations for each trace metal can be performed independently. 

The foct that one mole of Ca is released for one mole of Pb or Cd sorbed onto MLg shows that the process is one of ion exchange rather than adsorption. This stoichiometry cannot be explain by the biotic ligand model, also an adsorption model which assumes that metals act independently, even when metal competition is included [6]. 

The complexes that are formed are nonionic, and coordination to the Pu metal occurs in a bidentate mode through the carbonyl oxygens of the malonamide ligand. IR spectroscopy indicates C2v geometry of the extracted complex due to nitrate stretching bands at 1530-1540 cm" and 1280 cm The extracted species from complexation with DMDBTDMA are different than those that would be obtained with monamides, where the anionic complex Pu(N03)gH2(amide) t would be observed in the organic phase. Monamides are weaker complexants for Pu than are malonamides, due to nitrate/metal competition at high acid concentrations." ... 

Diamides. Malonamides have excellent chelating abilitities with trivalent actinides such as Am ", as well as with the lanthanides. The extracting ability of malonamides tends to increase with the decreasing basicity of the molecule this phenomenon is due to lower proton/metal competition with the less basic malonamide. Spjuth et studied the uptake of Am from HNO3 solutions by malonamides that had been tailored to vary the basicity of the ligand (see Table 49). 

Table 9 summarizes the opportunities and risks of this material group compared with metallic competitive products. 

This, of course, assumes a 100% current efficiency regarding metal dissolution, i.e. no other competitive electrochemical reactions occur. 

Both cis- and irans- 1,2-dibromoethylenes react with metal acetylides, but with different reactivity. For the competitive reaction of cis- and trans- fl-dibromoethylenes with the zinc acetylide 314 shows that the irans isomer is more reactive than the cis isomer[228,229]. It was also found by a competitive reaction with the zinc acetylide 317 that the irans vinyl monobromide 315 is more reactive than the cis isomer 316[230]. 

Viable glass fibers for optical communication are made from glass of an extremely high purity as well as a precise refractive index stmcture. The first fibers produced for this purpose in the 1960s attempted to improve on the quahty of traditional optical glasses, which at that time exhibited losses on the order of 1000 dB/km. To achieve optical transmission over sufficient distance to be competitive with existing systems, the optical losses had to be reduced to below 20 dB/km. It was realized that impurities such as transition-metal ion contamination in this glass must be reduced to unprecedented levels (see Fig. 

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

Many competitive programs to perfect a metallic anode for chlorine arose. In one, Dow Chemical concentrated on a coating based on cobalt oxide rather than precious metal oxides. This technology was patented (9,10) and developed to the semicommercial state, but the operating characteristics of the cobalt oxide coatings proved inferior to those of the platinum-group metal oxide. 

The first commercial plant to use CYANEX 272 became operational in 1985. An additional three plants were constmcted between 1985 and 1989. Of the four, one is in South America and three in Europe. An additional three plants have been built two in Europe (1994) and one in North America (1995). Approximately 50% of the Western world s cobalt is processed using CYANEX 272. Both high purity salts and electrolytic cobalt metal are recovered from solutions ranging in composition from 30 g/L each of cobalt and nickel to 0.2 g/L Co, 95 g/L Ni Operating companies usually regard use of CYANEX 272 as confidential for competitive reasons and identities cannot be disclosed. CYANEX 272 is being evaluated on the pilot-plant scale in many additional projects involving the recovery of cobalt and other metals. 

Machining costs (labor and overhead) in the United States have an estimated value of > 300 x 10 /yr. The cost of labor and overhead for machining is based on the estimated number of total metal-cutting machine tools in various metal-cutting industries (1). This value does not take into account the cost of raw stock (work material), cutting tools, and many other support faciUties. An estimated breakdown of cutting tool costs is given in Table 13 (172). Because of the competitive nature of these industries, most prefer to keep cost information proprietary. 

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