105 research outputs found

    The main geological factors influencing on formation of indices of coal quality (on the example of the coal deposit "Neryungrinskoye")

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    Genetic and epigenetic factors influencing on formation of a coal bed (its characteristics expressing by means of morphology, petrographic composition, degree of reducing, metamorphism, oxidation, and dislocation, physical properties and indices of coal quality) are considered. The main task of this research consisted in establishing of the significant factors influencing of the coal bed quality indices to a greater extent. Solution of the set task from positions of a system approach at study of rock massifs consisting in revealing and studying of many interconnected elements and estimation of their influence by means of alternate normalization of the main bounds is shown. The study was carry out in conditions of the bed «Moshny» of the coal deposit «Neryngrinskoye» of the Southern-Yakutia basin. The experimental data were treated with use of the correlation-regression methods. Results of researches allow to use geological information and geophysical methods for operative planning of geologic prospecting process and mining works in more total way

    Sulfidization of silver-polymetallic ores of «Goltsovoe» deposit for decreasing loss of silver in mill tailings

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    The results of laboratory studies of flotation concentration of silver-polymetallic ores of the Goltsovoe deposit at the Omsukchansk concentrator are presented. The results of sieve analysis of mill tailings of the experimental sample of MTP N 101 (N 7577-i) are described. They indicate that a large amount of silver (123 g/t) is lost in the size class – 0.040 mm (yield 50.25 %). According to the results of mineralogical analysis, it is established that the major losses of noble metal are associated with its fine impregnation in oxides, sulfides and silicate rocks. The main silver-bearing minerals are acanthite, polybasite and kustelite (class – 0.040 mm). Experimental studies were carried out in two stages. The purpose of the first stage is to determine the influence of grinding fineness in flotation feed (for a finished class content of 0.074 mm in the range of 60-95 %) for silver recovery at different amounts of butyl potassium xanthate (50, 150, 300 g/t). The purpose of the second stage is to evaluate the effectiveness of sulfidization at different consumption of sodium sulfide Na2S·9H2O (50, 150, 200, 450, 750 g/t – 1 % aqueous solution) under the conditions of the optimal reagent mode established in the first stage of the study. The results of experiments to determine the optimum grinding fineness and studies on the enrichment of silver-polymetallic ore with the use of sodium sulfide as a sulfidizer are presented. The efficiency of the sulfidization process is estimated. The following experimental dependencies of silver recovery are established: on the degree of grinding and consumption of butyl potassium xanthate; on variations of grinding fineness and the consumption of sodium sulphide (with a consumption of butyl xanthate 150 g/t); and on grinding fineness at optimum consumption of sodium sulfide 150 g/t and butyl potassium xanthate 300 g/t. A comparative evaluation of dependence of silver recovery index from the degree of grinding fineness before and after introduction of sodium sulphide (collecting agent consumption of 150 g/t) is given. The mathematical models describing the dependence of silverrecovery on technological parameters, allowing to control the process of flotation of refractory ore with a large number of primary sludges and the tendency of sludging during grinding and concentration (secondary sludges) are given. The optimal consumption of flotation reagents has been experimentally established: sodium sulfide 150 g/t, butyl potassium xanthate 300 g/t with rational grinding (the content of the finished class is 0.074 mm in the flotation feed 85-95 %). Absolute recovery of silver from the ore of the silver-polymetallic deposit «Goltsovoe» in comparison with the technological indicators of the Omsukchansk concentrator processing the material in accordance with the standard mode, increased by 14.1 % (from 70.7 to 84.8 %) with the yield 9.09 % due to intensification of recovery of silver-bearing semi-oxidized sulphides with reduced flotation activity and compensation of high absorptive capacity of fine particles. The amount of silver in the size class – 0.040 mm in the sample MTB N 101 (N 7698-i) after the use of sulfidization was 83 g/t at the yield of 72.01 %, which indicates the efficiency of the process. The losses of silver in mill tailings decreased by 40 g/t (32.52 %). This proves the possibility of processing silver-polymetallic ores of the Goltsovoye deposit without reclaimer operation

    Mild template synthesis of copper(II)-containing macrocyclic compounds in the CuII-1,2-diaminoethanedithione-1,2-ethanedione-1,2 and Cu II-1,2-diamino-ethanedithione-1,2-butanedione-2,3 triple systems into Cu2[Fe(CN)6]-gelatin-immobilized matrix implantates

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    The complexing processes in the CuII-1,2-diaminoethanedithione- 1,2-ethanedione-1,2 and CuII-1,2-diaminoethanedithione-1,2- butanedione-2,3 triple systems occuring in the copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-1,2 under room temperature, and between MCl2, 1,2-diaminoethanedithione- 1,2 and ethanedione-1,2 or butanedione-1,2 in the ethanol solutions, upon heating up to ~80 °C, have been studied. In both systems indicated, template synthesis occurs in the gelatin-immobililized matrix but does not occur in the ethanol solution. As a result of template synthesis, macrocyclic CuII chelates with 2,7-dithio-3,6-diazaoctadien-3,5-dithioamide-1,8 and its 4,5-dimethylsubstituted derivative are formed in the gelatin-immobililized matrix. 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-2,3 are the ligand synthons in the processes indicated. © 2007 Springer

    Copper(II)- heterocyclic compounds with 4,5-dimethyl-2,3,6,7-tetraazaoctadien-3,5-dithiohydrazide-1,8 and 3,10-dithio-6,7,13,14-tetramethyl-1,2,4,5,8,9,11, 12-octaazacyclotetradekatetraen-1,5,7,12 obtained in gelatin- immobilized matrix as a result of template synthesis

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    Soft template synthesis of macrocyclic coordination compounds with 4,5-dimethyl-2,3,6,7-tetraaza-octadien-3,5-dithiohydrazide-1,8 and 3,10-dithio-6,7,13,14-tetramethyl-1,2,4,5,8,9,11, 12-octaazacyclo-tetradekatetraen-1,5,7,12 in the triple Cu(II)-thiocarbohydrazide- 2,3- butanedione system in the copper(II)hexacyanoferrate(II) gelatin-immobilized matrix has been carried out. Also, it has been established that similar process in the nickel(II)hexacyanoferrate(II) matrices does not occur under such conditions

    Mild template synthesis in the Cu(II)-dithiomalonamide-formaldehyde ternary system

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    Complex formation in the ternary system Cu(II)-dithiomalonamide H 2NC(=S)CH2C(=S)NH2-formaldehyde in aqueous ethanol containing copper(II) chloride, dithiomalonamide and formaldehyde, as well as in thin-layer gelatin-immobilized copper(II) hexacyanoferrate(II) matrix implants contacting with alkaline (pH > 10) aqueous solutions containing the same organic compounds was studied. In the first case, a Cu(II) bischelate complex with singly deprotonated dithiomalonamide is formed exclusively, whereas in the second case template synthesis occurs to form a macrocyclic CuL chelate (L is 1,11-diamino-1,11-disulfanyl-4,8-diaza-6-oxaundeca-1,10-diene-3,9- dithione). In the latter case, dithiomalonamide and formaldehyde function as ligsons. The above-mentioned chelate is not formed on direct contact of the reagents in aqueus ethanol both in the presence and in the absence of Cu(II). A scheme of chemical reactions that occur in the system under consideration was proposed. © 2008 MAIK Nauka

    Floating matter: a neglected component of the ecological integrity of rivers

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    Floating matter (FM) is a pivotal, albeit neglected, element along river corridors contributing to their ecological integrity. FM consists of particulate matter of natural (e.g. wood, branches, leaves, seeds) and anthropogenic (e.g. plastic, human waste) origin as well as of organisms that, due to its properties, is able to float on the water surface. In this paper, we provide a comprehensive overview of the FM cycle and the fundamental environmental functions FM provides along rivers. Indeed, FM serves as an important geomorphological agent, a dispersal vector for animals and plant propagules, a habitat, a resource, and a biogeochemical component. Furthermore, we collected data on the amount of FM accumulating at dams and in reservoirs, and related it to key characteristics of the respective catchments. River fragmentation truncates the natural dynamics of FM through its extraction at damming structures, alteration in the flow regime, and low morphological complexity, which may decrease FM retention. Finally, we identify key knowledge gaps in relation to the role FM plays in supporting river integrity, and briefly discuss FM management strategies. (c) 2019, Springer Nature Switzerland AG.This work has been carried out within the SMART Joint Doctorate Programme ‘Science for the MAnagement of Rivers and their Tidal systems’, funded by the Erasmus Mundus programme of the European Union (http://www.riverscience.it). We also acknowledge financial support through the Excellence Initiative at the University of Tübingen, funded by the German Federal Ministry of Education and Research (BMBF) and the German Research Foundation (DFG). OS is thankful for a partial support from IGB equal opportunity fund for young female scientists and DFG (SU 405/10-1). SDL has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant agreement no. 748625

    Template synthesis in the Cu(II)-dihydrazinomethanethione-acetone ternary system

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    Complex formation in the Cu(II)-dihydrazinomethanethione (H 2NHN-CS-NHNH2)-acetone ternary system in an ethanol solution containing CuCl2, dihydrazinomethanethione, and acetone, as well as on contact of gelatin-immobilized copper(II) hecacyanoferrate(II) with alkaline (pH >10) aqueous solutions containing the above organic compounds was studied. It was found that template synthesis is realized in both cases but gives different products: in the first case, a heteroligand chelate of CuL 1(OH) with 9-hydrazino-9-mercapto-4,6,6-trimethyl-2,3,7,8- tetraazanona-3,8-dienethiohydrazide and hydroxide ion is formed, while in the second, a chelate of CuL2 with 2,8,10,10,16-pentamethyl-3,4,6,7,11, 12,14,15-octaazaheptadeca-2,5,7,12,15-pentaene-5,13-dithiol. In both cases, dihydrazinomethanethione and acetone function as ligsons. A scheme of involved processes is suggested. © 2009 Pleiades Publishing, Ltd. Reerernces:

    Mild template synthesis of a copper(II)-containing macrocyclic compound with 4,4,6-trimethyl-2,3,7,8-tetraazanonen-6-dithiohydrazide-1,9 in a gelatin-immbolized matrix

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    The complexing processes in the triple copper(II)-thiocarbohydrazide-propanone system taking place in a copper(II) hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous-alkaline solutions (pH∼12), containing thiocarbohydrazide and propanone, have been studied. Template synthesis leading to a macrocyclic coordination compound with the tetradentate N,N,S,S-donor ligand, (4,4,6-trimethyl-2,3,7,8-tetraazanonen-6-dithiohydrazide-1,9), occurs under these specific conditions when thiocarbohydrazide and propanone are the ligand synthons

    Interactions between diurnal winds and floodplain mosaics control the insect boundary layer in a river corridor

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    Insect flight along river corridors is a fundamental process that facilitates sustainable succession and diversity of aquatic and terrestrial insect communities in highly dynamic fluvial environments. This study examines variations in the thickness of the insect boundary layer (i.e., the pre-surface atmosphere layer in which air velocity does not exceed the sustained speed of flying insects) caused by interactions between diurnal winds and the heterogenous habitat mosaics in the floodplain of a braided river. Based on advective–diffusive theory, we develop and test a semi-empirical model that relates vertical flux of flying insects to vertical profiles of diurnal winds. Our model suggests that, in the logarithmic layer of wind, the density of insect fluxes decreases exponentially with the altitude due to the strong physical forcing. Inside the insect boundary layer, the insect fluxes can increase with the altitude while the winds speed remains nearly constant. We suggest a hypothesis that there is a close correspondence between the height of discontinuity points in the insect profiles (e.g. points with abrupt changes of the insect flux) and the displacement heights of the wind profiles (e.g. points above which the wind profile is logarithmic). Vertical profiles were sampled during three time-intervals at three different habitat locations in the river corridor: a bare gravel bar, a gravel bar with shrubs, and an island with trees and shrubs. Insects and wind speed were sampled and measured simultaneously over each location at 1.5-m intervals up to approximately 17 m elevation. The results support our working hypothesis on close correspondence between discontinuity and displacement points. The thickness of the insect boundary layer matches the height of the discontinuity points and was about 5 m above the bare gravel bar and the gravel bar with shrubs. Above the island, the structure of the insect boundary layer was more complex and consisted of two discontinuity points, one at the mean height of the trees’ crowns (ca. 15 m), and a second, internal boundary layer at the top of the shrubs (ca. 5 m). Our findings improve the understanding of how vegetation can influence longitudinal and lateral dispersal patterns of flying insects in river corridors and floodplain systems. It also highlights the importance of preserving terrestrial habitat diversity in river floodplains as an important driver of both biotic and abiotic (i.e., morphology and airscape) heterogeneity

    Interactions between diurnal winds and floodplain mosaics control the insect boundary layer in a river corridor

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    Insect flight along river corridors is a fundamental process that facilitates sustainable succession and diversity of aquatic and terrestrial insect communities in highly dynamic fluvial environments. This study examines variations in the thickness of the insect boundary layer (i.e., the pre-surface atmosphere layer in which air velocity does not exceed the sustained speed of flying insects) caused by interactions between diurnal winds and the heterogenous habitat mosaics in the floodplain of a braided river. Based on advective–diffusive theory, we develop and test a semi-empirical model that relates vertical flux of flying insects to vertical profiles of diurnal winds. Our model suggests that, in the logarithmic layer of wind, the density of insect fluxes decreases exponentially with the altitude due to the strong physical forcing. Inside the insect boundary layer, the insect fluxes can increase with the altitude while the winds speed remains nearly constant. We suggest a hypothesis that there is a close correspondence between the height of discontinuity points in the insect profiles (e.g. points with abrupt changes of the insect flux) and the displacement heights of the wind profiles (e.g. points above which the wind profile is logarithmic). Vertical profiles were sampled during three time-intervals at three different habitat locations in the river corridor: a bare gravel bar, a gravel bar with shrubs, and an island with trees and shrubs. Insects and wind speed were sampled and measured simultaneously over each location at 1.5-m intervals up to approximately 17 m elevation. The results support our working hypothesis on close correspondence between discontinuity and displacement points. The thickness of the insect boundary layer matches the height of the discontinuity points and was about 5 m above the bare gravel bar and the gravel bar with shrubs. Above the island, the structure of the insect boundary layer was more complex and consisted of two discontinuity points, one at the mean height of the trees’ crowns (ca. 15 m), and a second, internal boundary layer at the top of the shrubs (ca. 5 m). Our findings improve the understanding of how vegetation can influence longitudinal and lateral dispersal patterns of flying insects in river corridors and floodplain systems. It also highlights the importance of preserving terrestrial habitat diversity in river floodplains as an important driver of both biotic and abiotic (i.e., morphology and airscape) heterogeneit
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