360 research outputs found

    Role of magnetic degrees of freedom in a scenario of phase transformations in steel

    Get PDF
    The diversity of mesostructures formed in steel at cooling from a high-temperature austenite ("gamma") phase is determined by the interplay of shear reconstructions of crystal lattice and diffusion of carbon. Combining first-principles calculations with large-scale phase-field simulations we demonstrate a decisive role of magnetic degrees of freedom in the formation of energy relief along the Bain path of "gamma"-"alpha" transformation and, thus, in this interplay. We show that there is the main factor, namely, the magnetic state of iron and its evolution with temperature which controls the change in character of the transformation. Based on the computational results we propose a simple model which reproduces, in good agreement with experiment, the most important curves of the phase transformation in Fe-C, namely, the lines relevant to a start of ferrite, bainite, and martensite transformations. Phase-field simulations within the model describe qualitatively typical patterns at these transformations

    Mechanical safety of reinforced concrete structures at all stages of the life cycle

    Get PDF
    Ensuring the mechanical safety of operated buildings at all stages of the life cycle is an urgent task. This is especially important when planning major repairs and reconstruction in buildings, as well as determining the period of safe operation from the moment of the survey, i.e. clarification of the remaining service life. The total service life at the design stage is set by the customer and the general designer in accordance with the recommendations of GOST 27751-2014 «Reliability for constructions and foundations. General principles». Mechanical safety and durability are ensured when calculating structures using the limit state method, assigning protection measures depending on the operating conditions, as well as complying with the requirements of SP 255.1325800.2016 «Buildings and structures. Operating rules. General Provisions». A method for preliminary assessment of the mechanical safety of buildings and their structures is proposed for consideration, which eliminates some of the shortcomings of existing methods for calculating the residual life by physical wear (damage) of building structures based on the results of a visual inspection, the basis of which is the dependence of the allowable safe operation period on the percentage of reduced bearing capacity. It is proposed to use the results of a visual inspection performed in accordance with GOST 31937-2011 «Buildings and constructions. Rules of inspection and monitoring of the technical condition»

    Development of a Stress Sensor for Solids

    Get PDF
    The paper presents the results of experimental design of a cortex of the embedded stress sensor, which allows to determine stresses in the cross-section of large-scale laboratory monolithic structures made on the basis of mineral and polymer binders (concrete, gypsum, etc.). The objectives of the design were to develop a constructive solution of the stress sensor housing based on strain gauges, which has small dimensions, low manufacturing cost, as well as high resolution and stability of readings over the entire sensitivity area (stress up to 400 kgf/cm2).The stress sensor allows to determine the stress in laboratory structures with high accuracy, without significantly affecting the stress-strain state of the section at different stages of operation of the structural element

    On the taxonomical status of Aquilegia kansuensis (Ranunculaceae)

    Get PDF
    Для рода Aquilegia L. (Ranunculaceae) предложена новая номенклатурная комбинация – A. kansuensis (Brühl) Erst.DOI: 10.14258/turczaninowia.17.4.4 A new combination in the genus Aquilegia L. (Ranunculaceae) – A. kansuensis (Brühl) Erst have been proposed.DOI: 10.14258/turczaninowia.17.4.

    Achievements and prospects of applying high-throughput sequencing techniques to potato genetics and breeding

    Get PDF
    In recent years, marker-assisted selection (MAS) has been intensively used to increase potato breeding efficiency. Large-scale studies of the potato genome and genes exploiting next-generation sequence (NGS) approaches are required for broad application of MAS, genomic selection as well as genomic editing (the newest approach for creating potato with desired properties). In this review, trends in potato NGS-based research are overviewed, and related Internet resources are systematized. Special attention is given to peculiarities of the models and the approaches used in potato genetic studies, taking into account the complex organization of its genome and a high level of heterozygosity. In genetic studies diploids are used often, including diploid potato species, artificially obtained heterozygous dihaploids and homozygous double monoploids. The availability of artificially created diploid forms played an essential role in potato genome sequencing, which was completed in 2011. The Potato Genome Sequencing Consortium activities included not only constructing genome libraries, sequencing, assembling and annotation of the genome, but also genome sequence-based investigations uncovering features of potato genome evolution, SNP identification, analysis of genes and gene networks regulating resistance to phytopathogens and technological characteristics. An important outcome of the genome sequencing was further identification of more than 8 thousand SNPs and approbation of the Genotyping-by-sequencing (GBS) method on potato, which is the basis for potato genomic selection and for discovery of economically important genes using genome wide association studies (GWAS). Optimization of existing bioinformatic tools to support these studies, taking into account potato genome organization peculiarities, are carried out. This review gives analysis of databases containing potato genome and transcriptome sequencing results, as well as accompanying resources. This information should prove useful while planning comparative assays of potato transcriptome or application of DNA-markers. Sequencing of the genome as well as transcriptomes and microRNomes of cultivated potato and its wild relatives, on one hand, is of fundamental interest, assisting in detecting features of genome evolution, ontogenetic development and mechanisms of various environmental stresses responses. On the other hand, it is the basis for a wide range of practical applications for developing effective genomic and gene-specific markers and marker-assisted breeding of new potato cultivars with desired properties

    Ribosomal profiling as a tool for studying translation in plants: main results, problems and future prospects

    Get PDF
    The expression of eukaryotic genes can be regulated at several stages, including the translation of mRNA. It is known that the structure of mRNA can affect both the efficiency of interaction with the translation apparatus in general and the choice of translation initiation sites. To study the translated fraction of the transcriptome, experimental methods of analysis were developed, the most informative of which is ribosomal profiling (RP, Ribo-seq). Originally developed for use in yeast systems, this method has been adapted for research in translation mechanisms in many plant species. This technology includes the isolation of the polysomal fraction and high-performance sequencing of a pool of mRNA fragments associated with ribosomes. Comparing the results of transcript coverage with reads obtained using the ribosome profiling with the transcriptional efficiency of genes allows the translation efficiency to be evaluated for each transcript. The exact positions of ribosomes determined on mRNA sequences allow determining the translation of open reading frames and switching between the translation of several reading frames – a phenomenon in which two or more overlapping frames are read from one mRNA and different proteins are synthesized. The advantage of this method is that it provides quantitative estimates of ribosome coverage of mRNA and can detect relatively rare translation events. Using this technology, it was possible to identify and classify plant genes by the type of regulation of their expression at the transcription, translation, or both levels. Features of the mRNA structure that affect translation levels have been revealed: the formation of G2 quadruplexes and the presence of specific motifs in the 5’-UTR region, GC content, the presence of alternative translation starts, and the influence of uORFs on the translation of downstream mORFs. In this review, we briefly reviewed the RP methodology and the prospects for its application to study the structural and functional organization and regulation of plant gene expression

    Analysis of hadron production in nucleus-nucleus interactions up to and out of kinematical limit of free NN-collisions in the frame of FRITIOF model

    Full text link
    In the framework of the modified FRITIOF model, the inclusive spectra of the cumulative π0\pi ^0-, π\pi ^- -mesons and protons produced in the nucleus-nucleus interactions at 4.5 GeV/c/nucleon and 4.2 GeV/c/nucleon are calculated. It is shown that the model reproduces qualitatively, and in some cases quantitatively the main experimental regularities of π\pi-mesons production, and "soft" part of the proton spectra. According to the model the production of the cumulative particles is connected with the mechanism of the "soft" nucleon-nucleon interaction.Comment: 12 pages, 11 figure

    Correlation between structural and transport properties of ca-doped la nickelates and their electrochemical performance

    Full text link
    This work presents the results from a study of the structure and transport properties of Ca-doped La2NiO4+δ. La2−xCaxNiO4+δ (x = 0–0.4) materials that were synthesized via combustion of organic-nitrate precursors and characterized by X-ray diffraction (XRD), in situ XRD using synchrotron radiation, thermogravimetric analysis (TGA) and isotope exchange of oxygen with C18O2. The structure was defined as orthorhombic (Fmmm) for x = 0 and tetragonal (I4/mmm) for x = 0.1–0.4. Changes that occurred in the unit cell parameters and volume as the temperature changed during heating were shown to be caused by the excess oxygen loss. Typical for Ruddlesden–Popper phases, oxygen mobility and surface reactivity decreased as the Ca content was increased due to a reduction in the over-stoichiometric oxygen content with the exception of x = 0.1. This composition demonstrated its superior oxygen transport properties compared to La2NiO4+δ due to the enhanced oxygen mobility caused by structural features. Electrochemical data obtained showed relatively low polarization resistance for the electrodes with a low Ca content, which correlates well with oxygen transport properties. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The materials synthesis as well as electrochemical study were performed in a framework of the budget task of the IHTE UB RAS with using the equipment of the shared access center “Composition of compounds”. The TGA and isotope exchange studies were supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for Boreskov Institute of Catalysis (projects АААА‐А21‐121011390007‐7, АААА‐А21‐ 121011390009‐1). The SXRD experiments were performed at the shared research center SSTRC on the basis of the Novosibirsk VEPP‐3 complex at BINP SB RAS, using equipment supported by pro‐ ject RFMEFI62119X0022

    Floristic findings in the Upper Yenisei Basin (2)

    Get PDF
    В результате экспедиционных исследований, анализа ранее опубликованных работ и просмотра материалов, хранящихся в гербариях ЦСБС (NS, NSK) и государственного природного заповедника «Азас», уточнены сведения о видовом составе флоры бассейна Верхнего Енисея. Впервые во флоре Тывы отмечены Humulus lupulus, Atriplex hortensis, Saponaria officinalis, Raphanus sativus, Abutilon theophrastii, Cichorium intybus, Elodea canadensis, Cypripedium × ventricosum, Poa sergievskajae; во флоре Хакасии – Microcerasus tomentosa, Cypripedium × ventricosum, S. viridis subsp. pycnocoma; во флоре южной части Красноярского края – Microcerasus tomentosa, Cypripedium × ventricosum. Уточнено распростране- ние и обнаружены новые местонахождения редких на этой территории видов – Asterothamnus heteropappoides, Ulmus pumila, Saxifraga nivalis, Euphorbia caesia.As a result of field work, analysis of the works published earlier and study of herbarium specimens in CSBG and State Nature Reserve «Azas», data on species composition of the Upper Yenisei Basin flora were verified. Humulus lupulus, Atriplex hortensis, Saponaria officinalis, Raphanus sativus, Abutilon theophrastii, Cichorium intybus, Elodea canadensis, Cypripedium × ventricosum and Poa sergievskajae were noted for the first time in the flora of Tyva, Microcerasus tomentosa, Cypripedium × ventricosum and Setaria viridis subsp. pycnocoma – in the flora of Khakasiya, Microcerasus tomentosa and Cypripedium × ventricosum – inthe flora of southern Krasnoyarsk Krai. Distribution was specified and new localities of rare species: Asterothamnus heteropappoides,Ulmus pumila, Saxifraga nivalis and Euphorbia caesia were found

    High-Temperature Behavior, Oxygen Transport Properties, and Electrochemical Performance of Cu-Substituted Nd1.6Ca0.4NiO4+δ Electrode Materials

    Full text link
    In this study, Nd1.6Ca0.4Ni1−yCuyO4+δ-based electrode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) are investigated. Materials of the series (y = 0–0.4) are obtained by pyrolysis of glycerol-nitrate compositions. The study of crystal structure and high-temperature stability in air and under low oxygen partial pressure atmospheres are performed using high-resolution neutron and in situ X-ray powder diffraction. All the samples under the study assume a structure with Bmab sp.gr. below 350◦C and with I4/mmm sp.gr. above 500◦C. A transition in the volume thermal expansion coefficient values from 7.8–9.3 to 9.1–12.0 × 10−6, K−1 is observed at approximately 400◦C in air and 500◦C in helium.The oxygen self-diffusion coefficient values, obtained using isotope exchange, monotonically decrease with the Cu content increasing, while concentration dependence of the charge carriers goes through the maximum at x = 0.2. The Nd1.6Ca0.4Ni0.8Cu0.2O4+δ electrode materialdemonstrates chemical compatibility and superior electrochemical performance in the symmetrical cells with Ce0.8Sm0.2O1.9, BaCe0.8Sm0.2O3−δ, BaCe0.8Gd0.19Cu0.1O3−δ and BaCe0.5Zr0.3Y0.1Yb0.1O3−δ solid electrolytes, potentially for application in IT-SOFCs. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.122013100200-2; Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A21-121011390009-1; Ural Branch, Russian Academy of Sciences, UB RAS: 122020100324-3Material synthesis, sample preparation, and electrochemical studies were performed in the framework of budget tasks for the Institute of High Temperature Electrochemistry, UB RAS, project № 122020100324-3. The standard characterization of powder and ceramic materials was carried out at the Shared Access Centre “Composition of Compounds” of the Institute of High Temperature Electrochemistry, UB RAS. The synchrotron XRD experiments were performed at the shared research center SSTRC on the basis of the Novosibirsk VEPP-3 complex at BINP SB RAS. The in situ XRD study was carried out using the facilities of the shared research center “National Center of Investigation of Catalysts” at the Boreskov Institute of Catalysis (BIC). The part of the reported study concerning the crystal structure of the samples was funded within the framework of budget project for Synchrotron radiation facility SKIF, Boreskov Institute of Catalysis.BIC support of the isotope exchange study by the Ministry of Science and Higher Education of the Russian Federation projects AAAA-A21-121011390009-1 and AAAA-A21-121011390007-7 is greatly acknowledged. XPS study of the electrode materials was partly performed in the framework of the budget task for the Institute of Metallurgy, UB RAS, project № 122013100200-2 using the equipment of the Shared Access Centre “Ural-M” of the Institute of Metallurgy, UB RAS.Acknowledgments: Material synthesis, sample preparation, and electrochemical studies were performed in the framework of budget tasks for the Institute of High Temperature Electrochemistry, UB RAS, project №122020100324-3. The standard characterization of powder and ceramic materials was carried out at the Shared Access Centre “Composition of Compounds” of the Institute of High Temperature Electrochemistry, UB RAS. The synchrotron XRD experiments were performed at the shared research center SSTRC on the basis of the Novosibirsk VEPP-3 complex at BINP SB RAS. The in situ XRD study was carried out using the facilities of the shared research center “National Center of Investigation of Catalysts” at the Boreskov Institute of Catalysis (BIC). The part of the reported study concerning the crystal structure of the samples was funded within the framework of budget project for Synchrotron radiation facility SKIF, Boreskov Institute of Catalysis.BIC support of the isotope exchange study by the Ministry of Science and Higher Education of the Russian Federation projects AAAA-A21-121011390009-1 and AAAA -A21-121011390007-7 is greatly acknowledged. XPS study of the electrode materials was partly performed in the framework of the budget task for the Institute of Metallurgy, UB RAS, project № 122013100200-2 using the equipment of the Shared Access Centre “Ural-M” of the Institute of Metallurgy, UB RAS
    corecore