[en] The Lindenbaum algebra of Peano PA can be enriched by the n-consistency operators which assign, to a given formula, the statement that the formula is compatible with the theory PA extended by the set of all true Π_n-sentences. In the Lindenbaum algebra of PA, a lower semilattice is generated from 1 by the n-consistency operators. We prove the undecidability of the elementary theory of this semilattice and the decidability of the elementary theory of the subsemilattice (of this semilattice) generated by the 0-consistency and 1-consistency operators only. Bibliography: 16 titles.

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[en] The results of a study of the solubility of amorphous, hydrous ThO₂ over the pH range 3.5 - 14.2 are reported. The solubility is high at pH 3.5 and decreases rapidly at pH 4.5. The chemical modes of solubility over various pH ranges are discussed. No conclusive evidence for any amphoteric behavior of Th(IV) is reported. 22 references, 1 figure

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[en] The article is published in the original.

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[en] The phase boundary between the dilute phase and the two-phase region α+β of the vanadium tritide (VTsub(x)) system was determined for the first time. We observe a large shift of the terminal solubility to higher concentrations x as expected from the known behaviour of the VHsub(x) and VDsub(x) systems. The maximum solubility of the α-phase of VTsub(x) is about nine quarters of that for VHsub(x) in the temperature range between 25 and 80⁰C. (orig./RK)

[en] In the Scotia and Weddell Seas the concentration of dissolved Al was 1-1.5 nM in ice-free surface waters, up to 3 nM in ice-covered waters and about 2.6 nM in bottom waters. The solubility and the dissolution rate of diatomaceous silica, obtained from net samples and from incubations in the presence or absence of dissolved Al, were inversely related to solid-phase Al/Si ratios. At in situ temperatures, dissolution rates from Antarctic diatoms are higher than those for diatoms from temperature regions. Effects on distribution patterns of silicic acid in the Weddell Sea are discussed. (author). 32 refs.; 3 figs.; 2 tabs

[en] The miscibility gap (MG) of the Au-Pt binary system in the temperature range 600-1050 ^oC has been experimentally determined by the diffusion couple technique. The results show that the determined MG deviates from the currently accepted one, which shifts to the Au-rich side of the Au-Pt system. Based on the present experimental data, the Au-Pt system has been thermodynamically reassessed, with the result that the critical point of the miscibility gap is ∼1200 ^oC at 56 at.% Pt, in contrast to the currently accepted 1260 ^oC at 61 at.% Pt. The chemical and coherent spinodals of the Au-Pt system have been thus calculated.