In the south of the Far East of Russia, a new source of critically important metals (titanium and iron) has been discovered—ilmenite-titanomagnetite ores of mafic-ultrabasic rocks of the Sikhote-Alin ...orogenic belt. The results of studying the opening of the ilmenite-titanomagnetite ores of the ultrabasic rocks occurring in the Koksharovsky massif conducted with using both ammonium hydrofluoride NH
4
HF
2
and its mixture with ammonium sulfate (NH
4
)
2
SO
4
are presented. The usage of mixture of these reagents has proved to facilitate better opening of titanium-containing mineral raw materials. The experience of deep processing of ilmenite-titanomagnetite ores will allow outlining the ways for the industrial development of complex deposits of the Far East.
The article describes the main stages of deterioration and destruction of polyamide teeth of worm wheel gears in pump drive units and pipe fittings. Tribological process patterns are determined and ...recommendations are made for resource saving when replacing bronze with polyamide.
The methanotrophic bacterium Methylotuvimicrobium alcaliphilum 20Z is an industrially promising candidate for bioconversion of methane into value-added chemicals. Here, we have study the metabolic ...consequences of the breaking in the tricarboxylic acid (TCA) cycle by fumarase knockout. Two fumarases belonging to non-homologous class I and II fumarases were obtained from the bacterium by heterologous expression in Escherichia coli. Class I fumarase (FumI) is a homodimeric enzyme catalyzing the reversible hydration of fumarate and mesaconate with activities of ~94 and ~81 U mg.sup.-1 protein, respectively. The enzyme exhibited high activity under aerobic conditions, which is a non-typical property for class I fumarases characterized to date. The calculation of k.sub.cat /S.sub.0.5 showed that the enzyme works effectively with either fumarate or mesaconate, but it is almost four times less specific to malate. Class II fumarase (FumC) has a tetrameric structure and equal activities of both fumarate hydration and malate dehydration (~45 U mg.sup.-1 protein). Using mutational analysis, it was shown that both forms of the enzyme are functionally interchangeable. The triple mutant strain 20Z-3E (DELTAfumIDELTAfumCDELTAmae) deficient in the genes encoding the both fumarases and the malic enzyme accumulated 2.6 and 1.1 mmol g.sup.-1 DCW fumarate in the medium when growing on methane and methanol, respectively. Our data suggest the redundancy of the metabolic node in the TCA cycle making methanotroph attractive targets for modification, including generation of strains producing the valuable metabolites.
A new promising type of mineral resources, such as complex ores and placers spatially and genetically related to Late Mesozoic ultramafic intrusions, has been identified within the Sikhote-Alin ...orogenic belt. It is exemplified by the Ariadnoe massif of ultramafic rocks, in the center of which there is a gold–titanium mineralization deposit, and at the exocontact, a gold–antimony mineralization. The main mineralogical and geochemical features of gold–copper formations in its circum-intrusive zone are determined. Special focus is given to the finds of cuproauride, which are uncommon for the study area. To reconstruct the conditions of forming these ores, the isotope composition of sulfur in sulfide minerals is studied. The obtained data indicate the significant metal-bearing potential of the ultramafic rocks in Sikhote-Alin.
Abstract
The main mineralogical and geochemical characteristics, as well as the ore potential of titanium-bearing placers spatially and genetically associated with the Ariadne intrusion of ...ultrabasites (Primorye), were determined. The composition of ilmenite, gold and platinum was studied, and a complex of associated strategic metals was identified. The possibilities of industrial development of ilmenite placers applying environmentally safe methods of pyro-hydrometallurgy were evaluated. The proposed technical solutions will expand the prospects of the raw material base in the South of the Russian Far East.
A new promising source of mineral deposits is found in the southern part of the Far East of Russia: the Ti-bearing intrusions of ultramafic rocks of the Sikhote-Alin orogenic belt. The main ...mineralogical–geochemical features of antimonite–quartz veins are determined at the external contact of the Ariadnoe intrusion. It is shown that mantle and crustal processes were involved in the formation of Au–Ti and Au–Sb ores. The typomorphic properties of native gold in ultramafic rocks open new possibilities for re-estimation of the prospects of a mineral base of strategic metals of Primor’e.
Universal planar automata are universal attracting objects in the category of semigroup automata whose set of states and set of output signals are equipped with algebraic structures of the planes ...that are invariant under the actions of the transition and output functions. We establish the elementary definability of the class of universal planar automata in the class of semigroups and study the problem of the elementary classification of universal planar automata with the use of first-order theories of input signal semigroups of these automata.
Universal hypergraphical automata are universally attracting objects in the category of automata for which the set of states and the set of output symbols are equipped with structures of hypergraphs. ...It was proved earlier that a wide class of such sort of automata are determined up to isomorphism by their semigroups of input symbols. We investigate the connection between isomorphisms of universal hypergraphical automata and isomorphisms of their components: semigroups of input symbols and hypergraphs of states and output symbols.
Numerous occurrences of the precious metal mineralization located solely in the Jiamusi-Khanka province were detected within a single zone of the regional graphitization with ten kilometers ...submeridional strike towards the adjacent territories of the Primorsky krai (Russia) and the Heilongjian province (China), all the above said findings being obtained with the participation of the authors of the present scientific article. There are features of Dalnerechensk group (with Filinskoye being the largest of them), deposits of of Lesozavodsk group (Tamga, Turgenevo) and graphite-ore giant of Liumao Mashan group of the Heilongjian province in the Northern, central and Southern sides of this province respectively. The results of the isotopic-geochemical study of the graphite, the sulfides and the carbonates of these deposits, the formation of which has a common history with the one of the precious metal mineralization, indicate the participation of deep derivated recomposed fluids and the light isotopic-biogenic matter of the host rocks in the ore formation. Besides, the carbon and the oxygen from at least two more isotopic-contrast sources intruded into the ore-forming system. Some minerals were formed under the influence of the intrusive acidic melts on the carbonate rocks, other one were generated due to the involvement of the meteoric waters in the ore formation.
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