Home – Home – Jornals – Chemistry for Sustainable Development 2012 number 6

Carbon, though being abundant in the Solar system, barely exceeds 0.01 wt.% in the silicate mantle, whereas it is ~3.6 wt.% in primitive chondritic meteorites that most likely formed our planet. This deficit may be due to redistribution of carbon in the liquid metal phase and then in the core at the stage of magma ocean fractionation, because carbon is much more soluble in Fe-Ni ± S melt than in silicate melts. The terrestrial heat and mass transfer are controlled mainly by layered convection and periodic peaks of plume activity as fast mantle jets that rise from the core. Plumes carry significant amounts of CO₂, H₂O, and K₂O (most probably in the form of carbonatite or hydrous carbonatite melts) released by the degassing core on its interaction with oxidized silicate material. There are two mechanisms that may maintain fast plume ascent: (1) local melting at the plume front as a result of doping with volatiles (H₂O, CO₂) as in a gas burner (rise rate 60-110 cm/yr) or (2) flow controlled by diffusion transport of silicate components in carbonatite melt (rise rate ~100 cm/yr).

The Garevka metamorphic complex (GMC), located at the junction of the Central Angara and Isakovka terranes (western part of the Transangarian Yenisei Ridge), was studied in terms of its tectonometamorphic evolution and geodynamic processes in the Neoproterozoic history of the region. Geological, structural, geochronological, and petrological data permitted the recognition of two stages in the GMC evolution, which differ in thermodynamic regimes and metamorphic field gradients. These stages were related to crustal contraction and extension within the Yenisei regional shear zone, a large lineament structure in the region. Stage 1 was marked by the formation of metamorphic complexes in the middle to upper amphibolite facies moderate-pressure regional metamorphic settings at ~960 Ma, P = 7.7-8.6 kbar, and T = 582-631?C. This suggests subsidence of the area to the middle continental crust with dT/dH = 20-25?C/km. During stage 2, the rocks experienced Late Riphean (~880 Ma, SHRIMP II U-Pb and ⁴⁰Ar/³⁹Ar dating) dynamic metamorphism under epidote-amphibolite facies conditions ( P = 3.9-4.9 kbar; T = 461-547?C), indicating a metamorphic field gradient of dT / dH no greater than 10?C/km, with the formation of blastomylonites in narrow zones of ductile and brittle deformations. In these zones, high-grade GMC blocks were exhumed to the upper continental crust and underwent low-temperature metamorphism. Comparison of the structural, geologic, and other evolutionary features (nearly identical age constraints in view of exhumation rate, similar PT -paths, and different types of metamorphism associated with different geodynamic settings, etc.) of the Garevka and Teya complexes suggests that they constitute a single polymetamorphic complex.

Sesimic data on the southern (Laptev Sea) extremity of the Lomonosov Ridge were used to develop a new structural model for the sedimentary cover. It permitted a correlation between the seismic cross-sections of the ridge crest and two deep-sea basins: the Podvodnikov Basin and the Amundsen Plain. It is the first time that a seismic model has taken into account both regional seismic-reflection profiles obtained from NP drifting ice stations and recent high-resolution CDP data. Our seismic model agrees both with geological data on the Laptev Sea continental margin and the data obtained from deep-sea drilling into the Lomonosov Ridge under the IODP-302 project. The sedimentary cover of the southern Lomonosov Ridge and adjacent parts of the Amundsen Plain and Podvodnikov Basin was dated at the Aptian-Cenozoic. The sedimentary section is divided by two main unconformities, of Campanian-Paleocene and Oligocene-Early Miocene ages. The cover contains a structurally complicated graben system, which is an extension of the New Siberian system of horsts and grabens, recognized in the shelf. Sedimentation began in the grabens in the Aptian-Albian and ended with their complete compensation in the Paleocene.

We present new data on the material composition of terrigenous deposits in the pre-Jurassic basement of the West Siberian Plate, which formed on the margin of the Kazakhstan paleocontinent. Studies of the sections of several wells drilled in the east of the Kurgan Region showed that the Middle-Upper Devonian and lower Lower Carboniferous continental and littoral deposits are graywackes rich in rock and plagioclase clastics. Quartz grains amount to no more than 3-5%. The rock clastics are mainly volcanics of basic and normal compositions, which were supplied, most likely, from acting volcanoes of the marginal belt. By genesis, these are predominantly tephroids. Along with allothigenic components of sandstones, we consider authigenic minerals, which permit treating the postsedimentational transformation of the Middle Devonian and Early Carboniferous rocks as early catagenesis. By the vitrinite reflectance, the Lower Visean sandstones correspond to gradations MC₂ and MC₃ (medium catagenesis).

The formation and evolution conditions for alkaline magmatism and associated igneous rocks in the western framing of the Siberian craton are shown by the example of alkaline and subalkaline intrusive bodies of the Yenisei Ridge. We present petrographic, mineralogical, geochemical, and geochronological data for the rocks of the Srednetatarka and Yagodka plutons, located within the Tatarka-Ishimba suture zone. Ferroan and metaluminous varieties enriched with rare elements (Nb, Ta, Zr, Hf, REE) are making up most of the studied rocks. They formed at the stages of fractional crystallization of alkaline magma in a setting of active continental margin in the west of the Siberian craton in the Late Neoproterozoic (710-690 Ma). As differentiates of mantle magmas, these rocks associate with Nb-enriched rocks - A -type leucogranites and carbonatites. Sm/Nd and Rb/Sr isotopic data imply a predominance of the mantle component in the magmatic sources of the mafic and intermediate rocks as well as contamination of various volumes of continental crustal material by this magma.

We present the first results of studying the major- and trace-element composition of microinclusions in the coats of variety IV diamonds from the Sytykanskaya pipe. These microinclusions are of silicate-carbonate composition. Similar compositions are reported for the microinclusions in diamonds from the placers of the northeastern Siberian craton and cuboids from the Internatsional'naya pipe. The microinclusions studied are close to kimberlites and carbonatites in trace-element composition but depleted in HFSE, Mg, and transition metals and enriched in K and LILE. The distribution of incompatible elements in the microinclusions studied is similar to the "table" pattern, which was observed for high-density hydrous-silicic fluids.

High-Ba (~11 wt.% BaO) phlogopite was found for the first time in olivinites of the Guli intrusion in the Maimecha-Kotui province of ultrabasic alkaline rocks and carbonatites. The high-Ba mica occurs in assemblage with a paragenesis of olivinite minerals - clinopyroxene, titanomagnetite, apatite, and ilmenite.
High-Ba mica is an early phlogopite generation. Its magmatic crystallization led to a decrease in Ba content. Low-Ba mica is a late phlogopite generation. The high Ba/K ratios at the early stages of evolution of a mantle magmatic system are necessary for the formation of high-Ba minerals and point to magma formation at great depths and the contribution of mantle metasomatism to the geochemical characteristics of parental magmas.

The total hydrocarbon composition and average structural-group characteristics of typical Paleozoic crude oils of the Timan-Pechora petroliferous basin are described. The hydrocarbon (HC) types of crudes are compared, which were conventionally determined from the composition of their gasoline fractions, by mass-spectrometric analysis of the HC composition of crudes, and by structural-group analysis of crudes, based on radiospectrometric data. The analyses have shown the presence of 30 structural types of HCs with up to 43 carbon atoms. The whole series of members up to C₄₃ are specific only for HCs with no more than three rings in the molecule.
It has been established that the carbonate strata in the basin under investigation, independently of the depth of their occurrence and the age of the host deposits, generate and accumulate heavy high-resin high-sulfur oils rich in alicyclic structures and assigned by HC composition to the naphthene-methane or even naphthene type.
Terrigeneous reservoirs here abound in crudes of methane-naphthene type. The contents of sulfur and resinous substances and the fraction of carbon atoms in alicyclic HC structures decrease as the depth of occurrence of the host deposits grows, thus reflecting the known gradual process of "methanization" of petroleum composition.

We present new paleomagnetic data for continental flood basalts (Siberian traps) obtained from cores of two boreholes in the northwestern Noril'sk area, within the Kharaelakh and Vologochan basins. Paleomagnetic measurements of lava and tuff samples from KhS-59 and SSV-19 boreholes allowed reconstructing and correlating the polarity patterns. Thus, multiple paleomagnetic anomalies (PA) have been discovered as short-term polarity changes in narrow intervals of the magnetostratigraphic section above the principal reversal at the boundary between the Ivakin and Syverma Formations.
The most prominent anomalies are observed at the bases of the Morongo and Mokulai Formations. The samples from the anomalous intervals differ from those of other intervals neither in magnetic properties nor in mineralogy and magnetic grain sizes. Therefore, the revealed PMA record excursions of the geomagnetic field. Comparison of the results with the Meishan Global Stratotype Section and Point (GSSP) of the Permian-Triassic boundary implies a revision to the P-T position in the trap basalt succession of the Noril'sk area. Judging by the EMF behavior, basalts in this part of the trap province erupted for at least 500 Kyr during the interval of stable normal polarity.

Testing TEM systems has to include field experiments with physical models commensurate to the real transmitter-receiver configurations and to the target subsurface features. A large horizontal loop closed across a known resistance is a convenient model in this respect. It is convenient to lay in the field, it has manageable parameters, and its natural response is easy to calculate.
A field-size experiment and numerical modeling were applied to investigate the model wire loop response to eddy current in a uniform conductive ground, both at early and late times. The higher the resistivity of the ground, the larger the time range in which the measured response matches the predicted one, other things being equal.
The experiments show that (i) closed loops laid near a transmitter-receiver system are applicable to test the quality of the latter as a tool for TEM or other similar resistivity surveys; (ii) current induced in the model loop can be used to infer the resistivity of the ground; (iii) a closed loop slows down the growth and reduces the amplitude of voltage induced at early times in a receiver loop or in a multiturn coil.

A solution was found to the problem of recognizing a spatial three-dimensional group point object with coordinate noise, a priori uncertainty of angular parameters, and a shift of the initial vector component that defines the object. An iterative approach to matching angular parameters and vector descriptions of the recognized and reference groups of point objects is proposed.

Correlations for the lower limit of the estimate error variance of images distorted by additive and applicative noise are obtained. The potential and actual estimate error variances for linear and nonlinear filtering algorithms are analyzed. A combined filtering algorithm for images distorted by applicative noise is developed.

A new method of abandoned object detection based on analyzing a sequence of depth images is proposed, and algorithms of real-time determination of the quasi-stationary background and abandoned objects are developed. The efficiency of the proposed algorithms is compared with that of the algorithm based on analyzing brightness images.

A method of solving two-dimensional limited-angle tomography problems, based on the Cavalieri condition for the Radon transform, is investigated. Two algorithms realizing this approach are compared between themselves and also with the algorithm calculating missing projections from approximate tomograms. Numerical simulations show that all three algorithms allow the reconstruction accuracy to be improved in the case under consideration. Each of them, however, has certain specific features, which should be taken into account in solving practical tasks.

The emergence and development of algorithms for three-dimensional reconstruction in X-ray tomography are considered in historical sequence. The data completeness condition for precise reconstruction of an object at one point is studied. It is shown that some precise algorithms are used to reconstruct part of the object from data satisfying the completeness condition for this part. Other algorithms for solving the same problem require a full set of data for the entire object.

The construction of a reliability function from the results of accelerated failure time (AFT) models is considered. The constructed AFT models are verified by analyzing a sample of residuals. The fit of the residual sample to the baseline probability distribution is tested using modified nonparametric goodness-of-fit tests. In the absence of censoring in tests, it is proposed to use previously constructed models of distribution of statistics for testing composite hypotheses. In the case of censoring of type I or II, distributions of the goodness-of-fit test statistics are found by statistical modeling.

The problem of stabilization of an unstable plant by a reduced-order single-channel controller is considered. The possibility of compensating small deviations of a double inverted pendulum on a cart by acting on the cart is studied. An algebraic method for finding the extreme locations of the poles through the construction of root simplexes is proposed. Using this, the Hurwitz stability boundaries for various reduced-order controllers are calculated. It is shown that robust stabilization of the pendulum system in the class of reduced-order controllers is impossible.

The basis sources and methods of reducing the errors of incremental photoelectric digital converters for angular measurements are analyzed. A method of constructing hybrid photoelectric converters that increase the accuracy of angular measurements is proposed. The result is achieved by simultaneous measurements of the turning angle and current radial deflections of the converter shaft axis.

The influence of diffraction on the results of computer cytophotometry has been explored through experiments and theoretical analysis. The relative error introduced by diffraction is shown to depend significantly on the optical characteristics of the object: size and absorption. In computer cytophotometry, the choice of standards having a lower DNA concentration in nuclei with large sizes is found to be favorable for measurements of the length of the genomes of various organisms. It is proved theoretically and experimentally that the systematic error due to diffraction can be accounted for without the digital processing of each micro-image involving deconvolution procedures with the point spread function of the microscope.

A short-term memory structure (three-dimensional spheroidal retinoid) is proposed for stabilization of the wide-angle vision field and realization of the stereopsis process, as well as formation and storage of the binocular visual space in observer's consciousness.

It is found that damaged regions are formed around indium contacts to p-type CdHgTe {310} heteroepitaxail layers (HELs) on GaAs substrates and the sizes of these regions depend on the temperature and time of annealing in air. It is shown experimentally that at an annealing temperature of 90 ºC, the rate of expansion of the damaged regions is about 4 µm/h, and at temperatures of 120 ºC, it is more than 25 µm/h. After 488 hours of annealing of plates of CdHgTe HELs at 60 ºC in air, the formation of damaged regions around the indium contacts to the p regions was not observed. The studies were performed on plates of p-type CdHgTe HELs on GaAs substrates whose surface was covered with SiO₂ and Si₃N₄ dielectrics (with a total thickness of about 0.15 µm), with windows where p-n junctions were generated by ion implantation of boron.

Approaches to determining the unknown operator and the diagram of the neural network in the process of its analysis for diagnostics of digital systems are considered.

On the basis of a brief review and detailed analysis of the results of investigations of the chemical and other characteristics of soil in the tundra zone of Russia, a procedure is developed for the calculative determination of important agrochemical properties of natural and disturbed soil cover in tundra, in order to make quantitative evaluations of the ecological danger of its degradation. The initial data for calculations are the values of humus content in soil layer 0-20 cm, established experimentally or calculated on the basis of correlations with soil annealing losses, hygroscopic humidity of the upper soil layer and its organic component, and also the qualitative characterization of wetting and thermal conditions during the vegetation period. To illustrate the sequence and relevance of calculative determinations, an example of calculation and application results are presented.

The informative importance of one of the main signs characterizing humic acids of soils is considered, at diagnostics of the environment of their formation both at present and in the past. It is shown that the ratio of elements in humic acids exactly corresponds to the landscape conditions and quantitative characteristics of climatic indicators. They persist in time and can serve as one of the reliable indicators estimating the environment of different periods in paleogeografic history.

Features of the profile distribution of the biomass of soil microorganisms, total and specific metabolic activity of this biomass in frost soil of Central Yakutia are studied. Peculiarities of the changes of microbiological characteristics during the evolution of alas ecosystems and soils are analyzed. The effect of a complex of factors on the studies characteristics at different stages of long-term alas succession is evaluated.

Aftereffect of biological nitrogen produced by different plant genotypes was studied in gray forest and chernozem meadow soils. High efficiency was established for availability of fixed nitrogen by oats after super nodular form of peas. In the second year of aftereffect the yield gain with regard to the breed amounted to 11 % and 49 % on gray forest and chernozem meadow soils, respectively.

Effect of the application of fertilizers and under-winter cultivation (ploughing, moldboardless, no-tillage) on the content and composition of the soil organic matter was studied. Cultivation procedures did not have a substantial influence on the general content of total carbon, mobile humus and mortmass in soil layer 0-30 cm. However, between cultivation procedures, substantial differences in the distribution of carbon and mortmass were detected in this layer, which is due to the features of embedding plant residues into soil. Under the effect of long-term application of fertilizers in soil layer 0-30 cm carbon content С_total remained almost unchanged, while the content of mortmass carbon and mobile humus increased by about 10 %.

The possibility to create mesoscale soil maps of the natural systems of the Ukok Plateau on the basis of remote sensing studies, the principles of landscape zoning and spatial-temporal characteristics of natural environmental objects is considered.

Content and distribution of chemical elements in the soil of the Shira steppe in the Chulym-Enisey hollow are considered. Possible versions of the formation of specific features of the elemental composition of soil in lake depressions are analyzed.

Accumulation of Cu and Zn by 4-week germs of spring rape (Brassica napus L.) was studied in vegetation experiments with different doses of mono- and polyelemental pollution of liver-colored soil. It was demonstrated that the species Brassica napus L. can be recommended for Cu and Zn phytoextraction when there is polyelemental load on soil in the dose of 1 maximum permissible concentration; Cu - for any level of copper pollution, as well as Zn under the conditions of the minimal level of zinc pollution.

On the basis of generalization of the available results of the investigation into the traits and properties of chernozem in the Kuznetsk depression (Kuznetsk chernozem), it is concluded that these soils are the "gold fund" of the croplands of the Kuznetsk Basin: they served and now serve as irreplaceable basis for grain crop production in this most highly developed industrial region of West Siberia. However, in spite of the high anthropospheric significance, they are subjected to increasing erosion-deflationary destruction because even the simplest soil-protecting measures are not kept when using these soils as croplands. In addition, they are uncontrolledly assigned for open (quarrying) coal production, while the major coal resources are situated within the Kuznetsk depression, where the soil prevailing in soil cover is chernozem, arable soil of the best quality. In order to conserve Kuznetsk chernozem, compulsory tight control over the reasonability of its assignment for coal-producing industry is necessary.

Storage of reducible substances in the soils of coal-pit dumps is evaluated. It is ascertained that reducible substances content in 0.5-m strata of coal-pit dumps all over the region is 221 thousand tons and these substances consist of different forms of non-silicate iron. 19.5 % of these substances at that fall on compounds able to reduce and migrate with superficial water and intrasoil runoff in embryozems. Solutions arisen in this case exceed the maximum concentration limit of iron. It is shown that during forming man-caused landscapes it is necessary to provide conditions for the development of soil formation processes and faster attainment of humus-accumulative stage of soil evolution to prevent the negative consequences initiated by reducing processes proceeding in dumps.

Distinguishing features of the biological properties of perennial (40-45 years) dumps compared to the zonal soil at the territory of Mirninsky Mining and Processing Integrated Works were established. Comparison of the properties of dumps left for self-healing and those subjected to recultivation allows us to conclude that the biological efficiency of simplified reclamation scheme is low.

Modern analytical methods of the investigation of platinum-containing objects are considered, including the features and possibilities of the combined methods to determine trace amounts of platinum and palladium in surface water, soil and rocks. The data on metal content, the forms of their occurrence in geochemical systems and in technogenic sources from which they inter the environment are reported. The migration behaviour of different forms of platinum and palladium under the conditions characteristic of natural systems are considered, along with the results of model studies of the sorption behaviour of these elements at geochemical barriers.

The development of catalytic methods for the oxidation of organic compounds those fit contemporary environmental requirements represents a complicated and highly urgent task, especially for the processes of fine and pharmaceutical chemistry. This review summarizes data concerning the catalytic oxidation methods developed during the last 20 years for converting 2,3,6-trimethylphenol into 2,3,5-trimethyl-1,4-benzoquinone, a key intermediate for the synthesis of vitamin E. Also considered catalysts during 2,3,6-trimethylphenol hydroxylation in to 2,3,5-trimethyl-1,4-hydroquinone are considered, too.

Preliminary birch bark activation by steam under the conditions of explosive autohydrolysis was studied. It has been established that as the result of the preliminary processing the sorption activity of obtained enterosorbents with respect to methylene blue and gelatin exhibits a significant increase. The properties of enterosorbents resulted from autohydrolyzedyh phloem and silver birch bark have been compared. Conditions for the activation of birch bark by explosive authohydrolysis to obtain enterosorbents have been determined those could be better than commercial enterosorbent Polyphepan according to the sorption activity with respect to methylene blue and gelatin.

Results are presented concerning the studies on the formation of borate-containing aluminium oxide as a solid acidic catalyst system for the catalytic oligomerization of butenes. The possibilities of designing bi- and polyfunctional catalysts via modifying borate-containing aluminium oxide metals by metals and metal oxides from groups VI-VIII for the processes of oligomerizing ethylene, propylene, for single-stage production of ethylene, as well as for the processing of vegetable oil into diesel fuel components.

The basic aspects of environmental protection from hazardous gaseous impurities present in the exhaust gases of diesel engines are considered. Approaches used for the development of fundamental investigation of adsorbents and catalysts for afterburning СО and hydrocarbons are outlined. Results of the investigation of adsorption capacity of zeolites BEA and Y types with respect to heavy hydrocarbons (decane and toluene) obtained with the help of the gravimetric microanalyzer TEOM are presented. It is shown that both zeolites possess comparable capacities with respect to toluene, while the presence of mesopores in BEA zeolite determines its substantially larger adsorption capacity with respect to decane. For Pd/Al₂O₃ catalysts as example, the effect of the nature of precursor of active component and treatment conditions on the activity of the catalysts in the oxidation of CO is considered. It is demonstrated that in the case of the mass fraction of deposited chloride components up to 0.25-0.5 % atomically dispersed forms of palladium are formed; they are responsible for the high activity of palladium catalysts.

Prospective cyclic hydrocarbon combustion processes those differ by the type of chemisorbent are considered. In the carbonate cycle for СО₂ isolation from flue gases a high-temperature solid regenerable СО₂ chemisorbent is used. In the oxygen cycle, solid oxygen chemisorbent is used that is restored via contacting with fuel and oxidized when exposed to air. A common feature of such processes consists in solid-state reactions of binding and releasing the products or reactants at different stages of the process. Requirements for chemisorbents are determined concerning cyclic processes. Various factors affecting the efficiency of their use are considered, literature data concerning the efficiency of proposed СО₂ concentration cycles are presented.

Hemosorption (purifying the blood outside an organism) and enterosorption (detoxification of an organism through the gastrointestinal tract) are the most promising methods of the sorptional medicine. As far as the adsorption of toxic substances with different molecular mass and nature is concerned, carbon sorbents are of interest to meet the requirements of medicine. Sorbents of different nature and structure are described. Methods for controlling the adsorption activity of the sorbent are indicated. A particular attention is paid to the development of selective sorbents for using in sorptional medicine and proteomics.