692 research outputs found

    Descriptive study of the flora of the "Relic Oaks" landscape reserve (Eastern Siberia) in the context of the protected area importance for maintaining biodiversity

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    The article shows the importance of specially protected areas for preserving the gene pool of rare and useful plants in Siberia on the example of the "Relic oaks" state landscape reserve. The landscape reserve is located on the territory of Eastern Siberia (Russia), on the two large floristic areas of Holarctic: Circumboreal and East-Asian. During the study, 696 species of higher vascular plants have been identified in the territory of the landscape reserve. The prevailing families are following: Asteraceae, Poaceae, Ranunculaceae, Rosaceae, Cyperaceae, Fabaceae, Caryophyllaceae, Brassicaceae, Apiaceae, and Scrophulariaceae. In the territory of landscape reserve, 4 floral complexes were identified: alpine, forest, steppe and meadow-alluvial, as well as 10 chorological groups. The feature of the flora was prevalence of forest and steppe plant species with the East Asian type of habitat. By the number of species, herbaceous plants in the landscape reserve dominate over arboreal plants, and shrubs have the largest share among arboreal plants. The spectrum of life forms of plants shows the climatic conditions of the territory at the border of large floral areas and zones of vegetation. On the studied territory, there are 171 species of higher vascular plants (24.5% of the total flora composition in the landscape reserve), are rare and protected in various regions of Siberia

    Electrochemical Reducing of Terbium and Holmium Ions in the Sodium and Potassium Chlorides Melt with Equimolar Composition

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    Interest to rare-earth metals (REM) and their alloys is due to the possibility of using them for the creation of new materials need for modern technology. For instance, REM as alloying components allows for preparation of material with special magnetic properties. A promising method for forming such coating is the surface treatment of metals. This process has an electrochemical character as such for the organization of technology the knowledge of kinetics and mechanism of these processes is important. Despite significant interest in rare-earth metals, these issues are not well described in the literature. In order to choose an adequate mathematical model for calculation of kinetic primers, preliminary experiments that allow evaluating the reversibility of the electrode process have been conducted. Based on that, it was concluded that cathodic reduction of terbium and holmium ions in equimolar NaCl-KCl melt is irreversible. By means of voltammetric analysis, kinetic parameters (transfer coefficients, heterogeneous constants of charge transfer rate) of terbium and holmium electroreduction in equimolar NaCl-KCl melt were determined. The experiment was conducted in a three-electrode cell under a purified argon atmosphere. A dependency of kinetic parameters on the concentration of terbium and holmium chlorides wt (%): 1, 3, 5, 7, 10, was determined. The experiment was conducted in 1073–1173K temperature range. Values of kinetic parameters increase with temperature but decrease with the increase of REM chloride. Based on obtained data, it was found that electroreduction of chloride complexes LnCl63– (Ln–Tb, Ho) in equimolar NaCl-KCl melt is irreversible in the studied range of temperatures and REM concentrations. In summary of experimental data, in range of temperature and rare-earth chloride concentration, and assumption was made that reduction of terbium and holmium ions occurs in two stages. The process includes the preceding stage of complex dissociation. A mechanism of LnCl63– complex reduction in the mentioned melt is proposed. The obtained results are in agreement with literate data for analogues systems

    Determination Of Formation Regimes For Bilayer Cobalt Dysprosium Intermetalic Surface Alloy

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    High tech industrial fields on modern development stage are in need of construction materials with an optimal ratio of volume and surface properties, along with low cost of material itself. As evidenced by studies, in order to give a set complex of properties to a workpiece that operates under specific conditions, it is often sufficient to only modify its surface area. Over the course of studies, by means of gravimetric, influence of technological parameters (temperature and time samples are kept in the melt) on specific mass change of cobalt samples, that act as substrate, during electroless diffusive saturation with dysprosium in eutectic melt of lithium and potassium chlorides have been studied. A mathematical dependency was established for specific mass change of cobalt samples on time spent in melt for temperature range of 873–973 K. Composition of intermetallic coats obtained on surface of cobalt samples was studied means of EDX and SEM analyses. It was discovered, that for chosen temperature range, diffusion layers formed on surface of cobalt samples consists of two structural zones that correspond to Co-Dy and Cp2Dy phases

    Reconstruction of history of the Tatar Arch in the Neogene-Quaternary time by means of the morphometric analysis

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    The history of neotectonic development of the Tatar Arch is reconstructed according to the morphometric analysis data. High degree of neotectonic activity of the Southern Dome of the Tatar Arch is shown. Connections between the Tatar Arch morphostructure and its deep structure are traced. The research shows that the majority of local structures (of the second and third order) within the arch are recent formations aged by not more than 106 years old

    Assessment of the diversity of vascular plants in phytocenoses with a share of Quercus mongolica on the territory of Relic Oaks State Reserve

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    In this paper, we assess the diversity of vascular plants in phytocenoses with Quercus mongolica (family Fagaceae) on the territory of the Relic Oaks State Reserve (Eastern Siberia, Transbaikal region), where Q. mongolica is located at the northwestern boundary of the areal. The descriptions of phytocenoses have been processed in the PAST3 application. The similarity of species composition has been determined using the Jaccard index. The resulting tree diagram shows two groups of descriptions at a similarity level of 0.14-0.15. The first group includes the descriptions of mixed forest quadrats, in which Q. mongolica is a co-edificator. The second group of descriptions presents the communities where Q. mongolica is the only species in the tree layer. The analysis of the tree diagram shows the dependence of species richness within the phytocenoses on the surface patterns and edaphoclimatic conditions. The phytocenoses located on steep southern slopes show less diversity

    Seed morphology of some species in the family Gentianaceae

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    In this work, we investigated the outer and inner morphological characters of the seeds of 13 species in the family Gentianaceae. We also identified the main morphometric parameters and described the shape, coloration and sculpture of the seed surface. Some aspects of their internal structure were analyzed as well

    Efficient Model Learning for Human-Robot Collaborative Tasks

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    We present a framework for learning human user models from joint-action demonstrations that enables the robot to compute a robust policy for a collaborative task with a human. The learning takes place completely automatically, without any human intervention. First, we describe the clustering of demonstrated action sequences into different human types using an unsupervised learning algorithm. These demonstrated sequences are also used by the robot to learn a reward function that is representative for each type, through the employment of an inverse reinforcement learning algorithm. The learned model is then used as part of a Mixed Observability Markov Decision Process formulation, wherein the human type is a partially observable variable. With this framework, we can infer, either offline or online, the human type of a new user that was not included in the training set, and can compute a policy for the robot that will be aligned to the preference of this new user and will be robust to deviations of the human actions from prior demonstrations. Finally we validate the approach using data collected in human subject experiments, and conduct proof-of-concept demonstrations in which a person performs a collaborative task with a small industrial robot

    Features of mathematical modeling of in-situ combustion for production of high-viscosity crude oil and natural bitumens

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    © 2015 Springer Science+Business Media New York. Features of mathematical modeling of the process of recovery of high-viscosity crude oils and natural bitumens with use of in-situ combustion is examined based on a review of recent foreign publications. Hydrodynamic modeling is increasingly widely used. The importance of physical simulation on a "combustion-tube" apparatus, the results of which are irreplaceable in scaling-up the model to field dimensions, is demonstrated

    ENERGY CONSERVATION AS ONE OF CRITERIA FOR ESTIMATION ELECTRICAL POWER SOLUTIONS

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    The paper deals with enlarged technical losses in electricity distribution devices of substations and power lines. Authors developed formula to calculate the annual values of power losses, the resulting expressions can be used as one of the criteria for estimation electrical power solutions.В работе рассматриваются укрупненные технические потери в элементах распределительных устройств подстанций и линий электропередач. Разработаны формулы для расчета значений годовых потерь электроэнергии, полученные выражения предлагается использовать как один из частных критериев оценки проектных решений
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