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Introduction. Recently, sandwich-structured composite materials based on honeycomb core and strong thin shells have become widespread. However, these materials are characterized by manufacturing and operational flaws such as “non-gluing” and “delamination” that is the breaking of the bonds between the shell and the honeycomb core that result in the deterioration in the mechanical, acoustic and thermal properties of the material. Aim of the Study. The study is aimed at developing effective methods for detecting flaws in gluing shell with comb core in honeycomb polymer materials. Materials and Methods. The article describes a method for detecting these flaws using scanning thermography with a linear heat source, based on the estimation and subsequent analysis of the distribution of local temperature field gradients on the product surface. Results. The experiments were carried out on a model polymer specimen with an embedded artificial flaw; there were shown the main sources of emerging noise, control errors, and the ways to reduce their influence; a numerical method for assessing the accuracy of the flaw measurement method was proposed. Discussion and Conclusion. Tests carried out on a control specimen showed that the proportion of errors in measuring a defect does not exceed 12%

Introduction. Control of the presence of subsurface defects in products from composite materials is necessary for verification of products after release from production and in the process of operation. Aim of the Study. The purpose of the presented work is to estimate the parameters of subsurface defects using local laser thermography, suitable for quality control of both small objects and suspicious areas of large objects with curved surfaces. Materials and Methods. The laboratory setup on which this work was carried out includes a robotic arm, a COX CG640 thermal imager and a 3 W laser. The method was tested on a fiberglass sample with introduced delamination defect simulations located at different depths below the surface. By means of computer modeling rational parameters of thermographic control were selected, providing reliable detection of the defect at a depth of up to 3 mm under the surface of the composite sample. Results. Numerical modeling of surface temperature field induced by moving focused laser beam was carried out using COMSOL software package. It showed that laser beam with 3 W power moving at 5 mm/s provided the thermal contrast sufficient to detect the defects at the depth up to 3 mm. The obtained experimental data are in satisfactory agreement with numerical modeling both qualitatively and quantitatively. Experimental data were used to construct a regression model for determining defect depth based on the maximal thermal contrast and the time interval between heating and the contrast maximum. Discussion and Conclusion. The results obtained in this work allow us to propose a technique for detecting defects in fiberglass plastics and estimating their depth. The coefficient of determination for the obtained regression model was found to be equal to 0.95, and the mean square error of the metric was no more than 0.016 mm2. The use of a robotic arm to scan objects will make it possible to investigate objects with complex curved surfaces.

Wood as a material is a natural composite with a complex hierarchically arranged structure. All scale levels of wood structure contribute to its macroscopic mechanical properties. The nature of such characteristics and deformation modes differs radically at different scale levels. Wood macroscopic properties are well studied, and the relevant information can be easily found in the literature. However, the knowledge of the deformation mechanisms at the mesoscopic level corresponding to the cellular structure of early and late wood layers of annual growth rings is insufficient. It hinders building the comprehensive multiscale model of how wood mechanical properties are formed. This paper described the results of scanning of mechanical properties of softwood and hardwood samples, such as common pine, small-leaf lime, and pedunculate oak, by means of nanoindentation (NI). The NI technique allows varying the size of deformed region within a wide range by altering maximal load (Pmax) applied to the indenter so that one can repeatedly and non-destructively test wood structural components at different scale levels on the same sample without changing the technique or equipment. It was discovered that the effective microhardness (Heff) and Young's modulus (Eeff) decreased manifold with Pmax growing from 0.2 to 2 000 mN. This drop in Heff was observed when the locally deformed region grew, and resulting from Pmax increase generally follows the rule similar to the Hall-Petch relation for yield stress, strength, and hardness initially established for metals and alloys, though obviously in those cases the underlying internal mechanisms are quite different. The nature and micromechanisms of such size effect (SE) in wood revealed using NI were discussed in this study. At Pmax < 0.2 mN, the deformed area under the pyramidal Berckovich indenter was much smaller than the cell wall width. Hence, in this case, NI measured the internal mechanical properties of the cell wall material as long as free boundaries impact could be neglected. At Pmax > 200 mN, the indentation encompassed several cells. The measured mechanical properties were significantly affected by bending deformation and buckling collapse of cell walls, reducing Heff and Eeff substantially. At Pmax ≈ 1–100 mN, an indenter interacted with different elements of the cell structure and capillary network, resulting in intermediate values of Heff and Eeff. Abrupt changes in Heff and Eeff at annual growth ring boundaries allow accurate measuring of rings width, while smoother and less pronounced changes within the rings allow identification of earlywood and latewood layers as well as any finer changes during vegetation season. The values of ring width measured using NI and standard optical method coincide with 2%−3% accuracy. The approaches and results presented in this study could improve the understanding of nature and mechanisms lying behind the micromechanical properties of wood, help to optimize the technologies of wood farming, subsequent reinforcement, and utilization, as well as to develop new highly informative techniques in dendrochronology and dendroclimatology.

Link for citation: Plyusnin A.V., Sulima A.I., Marinov V.A., Vdovichenko S.I., SamodurovS.A. Results of studying the Pleistocene in the Vilgort section (Cherdyn district, Perm territory). Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.148-158.In Rus. The relevance. The study of glacial deposits, which is one of the main components of most continental sedimentary formations of all ages, makes it possible to identify the features of its structure and formation, as well as to establish the facies-genetic confinement. This is especially true for Quaternary geology, since makes it possible to carry out stratigraphic comparisons and identify paleogeographic settings for the formation of deposits. This paper presents the results of a comprehensive lithological and biostratigraphic study of the Vilgort section of the Kolva river valley, Cherdyn district of the Perm Territory. The main aim of the research is to study the geological section and substantiation of the age of the Mesozoic deposits according to the fauna complex. Objects: continental deposits of the Middle Pleistocene, exposed in the right side of the river Kolva. The deposits of this region are poorly studied. References are sown in the literature about the Mesozoic fauna found in the Vilgort section. Methods: geomapping, layered lithological description, layer-by-layer sampling, biostratigraphic studies. Results. These studies made it possible to carry out a detailed layer-by-layer description and stratigraphic subdivision of the Vilgort section. The Permian carbonate deposits are overlain by eluvial-deluvial deposits of the Likhvin horizon, they are overlain first by lacustrine-glacial, and then by glacial deposits of the Dnieper horizon of the middle Pleistocene with erratic blocks of Mesozoic repeatedly redeposited terrigenous rocks. Due to the neotectonic activity of the right-bank block part of the Vilgort area, which underwent uplift in the Late Pleistocene, most of the Upper Pleistocene deposits were eroded, which explains the stratigraphic unconformity, when modern deposits lie on glacial deposits of the Middle Pleistocene. According to the results of micropaleontological studies, foraminifers were identified from samples taken in the fifth layer: the Middle Volgian substage of the Volgian stage (sample 1); distributed in the interval of the Ryazanian Stage of the Lower Cretaceous (sample 3) and the middle and upper substages of the Volgian Stage (sample 4).

Quantitative petrography is a scientific and industrial direction of geology, which made huge progress due to developments and inventions in information technology and optics in the last decade. This article is introducing the modern and scientific directions of quantitative petrography and describes their current state of art as well as methodical approaches and their application. The research objects of quantitative macropetrography are hand specimens, borehole cores and polished tiles, and of micropetrography are thin and polished sections of rocks samples, splitted rock surfaces and immersion preparations. The goal of the research is to develop and present new methodological approaches of digital microscopy for the analysis of ores, rocks and minerals, as well as to investigate the morphological image analysis capabilities for the transforming from the classical description methods to quantitative petrography.

The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people are involved in the data collection.Within 20 months the participants accumulated over 750,000 photo observations of 6,853 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 85% of all project data are available under free licenses (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities.

Обобщены методические подходы и результаты флуоресцентной макро- и микропетрографии горных пород. Известно, что флуоресценцию минералов вызывают не их макроэлементы, а примеси (активаторы). В результате использовать флуоресценцию для идентификации минералов из разных месторождений не представляется возможным, так как активаторы в этом случае неодинаковы. Однако в пределах одного месторождения флуоресценция является надежным типоморфным признаком, поскольку минералы с данными флуоресцентными характеристиками имеют единый источник формирования. Обсуждаемый методический подход основан на комбинации эпифлуоресцентной микроскопии и мультифокальной петрографии пород. Ультрафиолетовое исследование в режиме «на отражение» имеет ряд преимуществ, особенно при изучении дисперсных осадочных пород: улучшение разрешения микрофотографий, отсутствие перекрытия микрочастиц внутри шлифа при исследовании его «на просвет». В отличие от классической петрографии, в которой используется свет от источника освещения, в ультрафиолетовой петрографии флуоресцирующие минералы сами излучают свет, что также повышает разрешающую способность данного метода. Ультрафиолетовые исследования, выполненные на образцах пород надсолевой верхнедевонской толщи Старобинского месторождения калийных солей, выявляют полигенные процессы формирования этих пород. В составе терригенного материала алевритовой размерности выделяются минералы с малым и большим выходом флуоресценции, поступавшие в бассейн седиментации из разных источников. Основная масса мергелей, состоящая из дисперсного кальцита и глинистых минералов, в ультрафиолете демонстрирует структуры, невидимые для других методов исследования осадочных пород, ‒ колломорфное агрегатное строение, зоны низкотемпературного метасоматического замещения агрегатов мергеля, связанных с системой трещиноватости пород. Флуоресцентные свойства гидротермальных и хемогенных минералов позволяют эффективно обнаруживать эти минералы в составе нормально-осадочных пород. Примером могут служить бораты в солях эвапоритовых формаций. Однако для установления минеральной разновидности таких образований требуется комплексный подход с использованием рентгенофлуоресцентного и дифрактометрического анализа.

The paper presents the results of ice strengthening by means of ultrafme silica nanoparticles introduced to distilled water prior to its crystallization. Stable SiO2 particles suspensions with concentrations ranging from 0.003 to 5 wt % have been prepared, and nanoparticles size distribution and zeta potential have been monitored in them. Both values remain almost constant for a week. Concentration dependences of maximal stress, Young's modulus and inelastic deformation at and after reaching peak stress in uniaxial compression test have been studied. The highest rate of change with the particles concentration for these properties is between 0.01 and 1 wt % while beyond the above range the concentration sensitivity is much weaker. The strongest effect of silica concentration is on inelastic deformation, and the weakest effect is on Young's modulus. Concentration sensitivity of the properties has been estimated by the power index of the best fitted power function for each of the property. Dependence of strength upon average grain size, that diminishes sixfold with growing concentration, is well approximated by power function also, but with negative power index –1/2. Additive constant in this dependence is found to be much lower than the strength of large grain pure ice and is close to zero within experiment accuracy. Hence, the strength of studied polycrystalline ice and ice composites is limited by the nucleation and subsequent propagation of Griffiths cracks with characteristic length proportional to average size of ice grain. [ABSTRACT FROM AUTHOR]

Integrated data of the structure and mineralogical composition of the marking tuff horizon in the Upper-Devonian bed of the North-Shestovich synclinal zone are presented in this paper. Dependence of the tuff bed structure on the volcanic activity stage is revealed. Find out that the prevailing mineral of tuff is the structure-ordered illite 1M. Marked tuff horizon is situated inside the Upper-Devonian salt bed within Petrikov synclinal zone and comes up into the overlaying clay-marl formation of the surrounding geological beds.

The goal of the article is to show how bankruptcy of an enterprise appears. Therefore, the generalised balance equation of financial and economic activity of the enterprise is considered. Graphs of two main characteristics of risk management are given. The conditions under which the income and expense curves can re-intersect are given. From this moment the bankruptcy procedure of the enterprise begins. There are four stages through which the company must pass until it is declared bankrupt. It is also indicated how zones of permissible, critical and catastrophic risks arise. On the basis of business speed and investment profitability, a table of SWOT analysis of financial improvements of the enterprise is built. Four strategies of economic security and possible risks are also considered. An example of one of the methods of financial recovery of the enterprise using intermediate risky activities is given. By means of calculations it is shown that long participation in risky business, can bring both the considerable income, and lead to almost complete loss of the capital. The conclusion is made: it is necessary to leave risky business in time.

Purpose: The goal of the work is to develop a workable technique for fast processing of large arrays of radio astronomy data to search for responses to extragalactic transient events, which a priori should have large dispersion (DM ~ 100÷2000 pc · cm-3). Records of 20-day continuous observations of the sky sphere circumpolar zone with an area of about 8 sq deg and separate files with repeating fast radio burst FRB 121102 were used as a test sample of the technique. Design/methodology/approach: The BSA (Big Scanning Antenna) LPI radio telescope has a multi-beam diagram and is capable of recording daily in the frequency range of 109–111.5 MHz in 96 beams in the declination range from – 8° to +42°. The number of frequency bands varies within 6 to 32 for the time constant varying within 0.1 to 0.0125 s, respectively. In the mode of recording 32 frequency bands with the time constant 0.0125 s, 3.4 GB of data are recorded every hour, 87 GB – daily, and 32 TB – per year. To end of August 2018, about 120 TB of data have been accumulated. Processing this amount of data for a number of scientific problems urgently requires the use of high-performance computing technologies. Findings: The paper proposes two ways to process data: using graphics processors (CPU+GPU, calculation in the C/C++ programming language using OpenCL) and using cluster computing (by using the message passing interface MPI on multiprocessor nodes). To refine the methodology, we use both the processing of pulsar data (using graphic accelerators allows us to increase the processing speed by 2–3 orders of magnitude) and search for responses to extragalactic transient events, which a priori should have large dispersion delays. Examples of such events include fast radio bursts (FRB), responses to gamma radio bursts (GRB) and, finally, possible responses to gravitational events recorded by the LIGO detectors. After processing the polar zone, 697 candidates for pulsed events with high dispersion measures were detected. About half of them is caused by man-made interference, the rest being caused both by the usual interplanetary scintillations of radio sources, and also by the possible soughtfor FRBs. It is still difficult to separate these two classes of events. Processing the data observed in the FRB 121102 zone also indicates the presence of event candidates. The results require more thorough analysis. Сonclusions: After finalizing the high-performance computing methodology, it will allow us to process data observed with the BSA LPI multipath diagram immediately after they are recorded.