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Atmospheric correction of satellite remote sensing data is a prerequisite for a large variety of applications, including time series analysis and quantitative assessment of the Earth's vegetation cover. It was earlier reported that an atmospherically corrected KMSS-M (Meteor-M #2) dataset was produced for Russia and neighboring countries. The methodology adopted for atmospheric correction was based on localized histogram matching of target KMSS-M and MODIS reference gap-free and date-matching imagery. In this paper, we further advanced the methodology and quantitatively assessed Level-2 surface reflectance analysis-ready datasets, operatively produced for KMSS-2 instruments over continental scales. Quantitative assessment was based on accuracy, precision, and uncertainty (APU) metrics produced for red and near-infrared bands of the KMSS-2 instrument based on a reference derived from a MODIS MOD09 reconstructed surface reflectance. We compared error distributions at 5%, 20%, and 50% levels of cloudiness and indicated that the cloudiness factor has little impact on the robustness of the atmospheric correction regardless of the band. Finally, the spatial and temporal gradients of accuracy metrics were investigated over northern Eurasia and across different seasons. It was found that for the vast majority of observations, accuracy falls within the −0.010–0.035 range, while precision and uncertainty were below 0.06 for any band. With the successful launch of the most recent Meteor-M #2.3 with a new KMSS-2 instrument onboard, the efficiency and interoperability of the constellation are expected to increase. [ABSTRACT FROM AUTHOR]

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive histological type of cancer in this location. Distant metastases are present in approximately 30% of patients at the time of first examination. Therefore, the ability to predict the occurrence of metastases in patients at early stages of the disease is an urgent task aimed at personalized treatment. Samples of tumor and paired histologically normal kidney tissue from patients with metastatic and non-metastatic ccRCC were studied. Gene expression was analyzed using real-time PCR. The level of gene methylation was evaluated using bisulfite conversion followed by quantitative methylation-specific PCR. Two groups of genes were analyzed in this study. The first group includes genes whose expression is significantly reduced during metastasis: CA9, NDUFA4L2, EGLN3, and BHLHE41 (p < 0.001, ROC analysis). The second group includes microRNA genes: MIR125B-1, MIR137, MIR375, MIR193A, and MIR34B/C, whose increased methylation levels are associated with the development of distant metastases (p = 0.002 to <0.001, ROC analysis). Based on the data obtained, a combined panel of genes was formed to identify patients whose tumors have a high metastatic potential. The panel can estimate the probability of metastasis with an accuracy of up to 92%. [ABSTRACT FROM AUTHOR]

This work studies the phase composition, structure and mechanical properties of composite materials obtained by high-temperature vacuum sintering of SHS-fabricated CrNi–TiN powders synthesized in semi-industrial-scale production conditions. It was found that changes in the synthesis conditions have no effect on the phase composition and structure of the final products. Additionally, a small increase in the average size of ceramic TiN particles was observed. Compacted rectangular samples were obtained by high-temperature vacuum sintering of fine-ground CrNi–TiN SHS products. A minimum sintering temperature was found at which specimens with a density of 95% of the theoretical one could be obtained. The structure of sintered composites inherits the metal-matrix structure of a part of SHS products. It was shown that CrNi–TiN composite materials are superior to NiTi–TiB2 composites in terms of hardness as well as binding strength for three-point bending at temperatures up to 550 °C. [ABSTRACT FROM AUTHOR]

The Hugoniot elastic limit and spall strength were measured for a heat-resistant metal-matrix composite Inconel 625–5%NiTi–TiB2 alloy additive manufactured (AM) by direct laser deposition. The strength characteristics of the alloy were obtained from the analysis of the complete wave profiles recorded with a VISAR laser Doppler velocimeter during shock-wave loading of the samples. The samples were loaded using a PP50 pneumatic gun or ad hoc explosive devices along and across the material deposition direction in order to determine the strength anisotropy of the AM alloy under study. The maximum shock compression pressure was ~7 GPa, and the strain rate under tension before spalling varied in the range of 105–106 s–1. Kinetic dependencies of elastic/plastic transition and critical fracture stresses vs. loading conditions were plotted. It was shown that the Hugoniot elastic limit of the alloy under study decreases as the shock wave travels into the sample, while the spall strength increases as the material's strain rate increases at the moment of spall fracture. A comparison of the strength characteristics of the Inconel 625–NiTi–TiB2 composite alloy with the original Inconel 625 alloy has shown that an addition of 5% of powder based on NiTi-TiB2 leads to a decrease in its elastic limit and critical fracture stresses upon spalling by more than 10%. The alloy under study demonstrates anisotropy of strength properties relative to the material deposition direction. [ABSTRACT FROM AUTHOR]

This paper studies the impact of the mass fraction of NiTi–TiB2 particles obtained by the method of self-propagating high-temperature synthesis (SHS) on the phase composition, structure, and mechanical properties of composites made by direct laser deposition from an Inconel 625–NiTiz–TiB2 powder mixture. Composites were obtained from a powder mixture with the mass fraction of particles at 5–10 wt%, and they consisted of an Inconel 625 metal matrix wherein ceramic inclusions of titanium diboride TiB2 were distributed. Increasing the mass fraction of SHS-produced NiTi particles from 30 to 95 wt% led to the emergence of a NiTi intermetallide phase in the matrix material as well as an increase in the average TiB2 particle size and formation of their agglomerates. In addition, an increase in the microhardness of the materials was observed. The graph of tensile strength of Inconel 625–NiTi–TiB2 samples has a parabolic shape with a maximum at 1000 MPa (when the mass fraction of SHS-produced NiTi–TiB2 particles is at 30 wt%). A further increase in the mass fraction of NiTi–TiB2 led to a decrease in the tensile strength down to 400 MPa. Here the deformation of samples decreases linearly as the ratio of composite particles in the initial mixture increases. From a comparative analysis of the results obtained, the optimal mass fraction of composite NiTi–TiB2 particles in the Inconel 625-NiTi–TiB2 powder mixture was found to be 5 wt%. [ABSTRACT FROM AUTHOR]

In the presented research work, 3D materials were fabricated by additive moulding by means of extrusion of a mixture of high filled polymers and nanopowders of Ti-Al intermetallides with subsequent sintering at 1100 ± 20 °C, 1200 ± 20 °C and 1250 ± 20 °C (MEAM-HP process). Nanopowders of Ti-Al intermetallides were obtained by the electrical explosion of intertwined aluminium and titanium wires. It was found that the structure of the materials comprises an AlTi matrix with Ti2AlN MAX-phase particles distributed within it, surrounded by a composite layer of Ti3Al-Ti2AlN. Sintering temperature increases led to changes in the concentration of TiAl, Ti3Al and Ti2AlN phases in the samples. Besides that, aluminium oxide particles were discovered in the structure of the materials. It was found that as the sintering temperature was increased from 1100 ± 20 °C to 1250 ± 20 °C, the average microhardness of the samples increased from 193 to 690 HV0.1. [ABSTRACT FROM AUTHOR]

This article considers issues pertinent to the research of the phase composition, structure and mechanical properties of materials obtained from powders of composite (Ni-Ti)-TiB2, which have prospective applications in aerospace and automotive industry and engine construction. The starting powder materials (Ni-Ti)-TiB2 were obtained by self-propagating high-temperature synthesis (SHS). Research samples were produced using high-temperature vacuum sintering. It was shown that the use of such materials increases the wettability of the particles and allows the production of composites, the density of which is 95% of the theoretical one. Average particle size was 1.54 µm, average microhardness was 8 GPa, which is an order of magnitude higher than the average microhardness of pure nickel-based and titanium-based alloys, and the ultimate strength values were comparable to those of tungsten-based heavy alloys. [ABSTRACT FROM AUTHOR]

In this work, composite materials were obtained by spark plasma sintering of an Al12Mg17-B-Si powder mixture. The structure, phase composition, and mechanical properties of the obtained composites were studied. It was found that various compounds based on B12 icosahedrons, such as AlB12, B4Si, and B6Si, are formed during spark plasma sintering. Based on the SEM images and results of XRD analysis of the obtained specimens, a probable scheme for the formation of the phase composition of composite materials during spark plasma sintering was proposed. An increase in the Al12Mg17-B powder content in the initial mixture from 30 to 70 wt% leads to an increase in hardness from 16.55 to 21.24 GPa and a decrease in the friction coefficient and wear rate from 0.56 to 0.32 and 13.60 to 5.60 10−5 mm−3/(N/m), respectively. [ABSTRACT FROM AUTHOR]

In this study, we successfully obtained Al-TiB2 composite materials using self-propagating high-temperature synthesis and preliminary mechanical activation of the initial Al-(Ti + 2B) powder mixture with a high aluminum content (70 wt.%). We investigated the possibility of controlling the structure of synthesis products, in particular, the size and shape of ceramic particles. We examined the effects of the mechanical activation of the initial powder mixture on the structure and particle size of titanium diboride in the synthesis products. We proposed a mechanism of structure formation in the synthesis products obtained by SHS using the method of preliminary mechanical activation of the initial mixture. We found that mechanical activation for 60-180 s led to the formation of isolated TiB2 particles of prolate and irregular shape. The average particle size of TiB2 in the synthesis products was 0.77 (after 60 s of mechanical activation) and 1.5 µm (after 180 s of mechanical activation), respectively. An increase in the duration of mechanical activation to 900 s led to the formation of an island (skeletal) structure, in which there were interconnected aggregates and isolated particles of titanium diboride. The average size of these particles was 4.3 µm. [ABSTRACT FROM AUTHOR]

This research work studies the structural phase parameters and physicomechanical properties of metal-matrix composite materials based on a Ni–TiB2 system obtained by additive manufacturing (specifically, direct laser deposition). The properties of the composites obtained were investigated at high temperatures (up to 1000 °C). The feasibility of the fabrication of a composite nanostructure of alloy with advanced physicomechanical properties was shown. The introduction of reinforcing TiB2 particles into an Inconel 625 matrix was confirmed to increase the microhardness and tensile strength of the material obtained. Apparently, the composite structure of the samples facilitates the realisation of several strengthening mechanisms: (1) a grain boundary mechanism that causes strengthening and dislocation movement; (2) a mechanism based on the grain structure breakdown and Hall–Petch relationship realisation. [ABSTRACT FROM AUTHOR]

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy. [ABSTRACT FROM AUTHOR]

The novelty of this work consists of obtaining original fundamental data on the laws of synthesis of new metal matrix composite materials for additive technologies. CrN + TiNi composites were obtained using the method of self-propagating high-temperature synthesis. In this work, analysis of the parameters of the synthesis of composite materials as well as their structure and phase composition were carried out. A scheme for the formation of a composite structure is established; it is shown that the phase composition is represented by 54.6 wt.% CrN and 45.4 wt.% TiNi. It was shown that composites based on the system are suitable for machines that make use of direct laser deposition to grow layers of materials. Sample structure and phase parameters were studied. It is shown that titanium nitride particles are uniformly distributed in the CrNi intermetallic matrix, the TiN particle size ranges from 0.3 to 9 μm and the average particle size is 2.8 μm. The results obtained indicate the possibility of synthesizing promising metal matrix composite materials for additive technologies. Such materials may have increased hardness, operating temperature and strength. [ABSTRACT FROM AUTHOR]

According to the data reported by the international and governmental agencies, the Russian Federation remains one of the world's major associated petroleum gas (APG) flaring nations. In the past decade, numerous studies have shown the applicability of satellite-based methods to estimate gas flaring. New satellite-based observations might offer an insight in region-, company-, and site-specific gas flaring patterns, as the reported data are often incomplete. We provide a detailed catalog of the upstream and downstream gas flares and an in-depth analysis at the country, region, company and site level of the satellite monitoring results of flaring in Russia from 2012 to 2020. Our analysis is based on the VIIRS Nightfire data and validated against high-resolution daytime satellite images and geographical and geological metadata published by the oil and gas companies and the Russian government. Gas flaring volumes in Russia are estimated to average at 23 billion cubic meters (BCM) annually (15% of global flaring), with 19 BCM (82% on national scale) corresponding to the oil upstream flaring, which has been subject to heavy government regulations since 2013. Despite initially dropping, observed flaring volumes have been on the climb since 2018. We are able to monitor seasonal variations, accidents in gas processing and to track the activities to reduce gas flaring. An effect of gas composition on the flare temperature is reported for oil and gas fields in Russia. [ABSTRACT FROM AUTHOR]

The paper explores the influence of planetary milling on the temperature and velocity of Al-Ti-B powder mixture combustion and also on the structure and phase composition of the reaction products. It is found that the time increase of planetary milling modifies the structure of the powder particles, improves the density of compacted specimens, and increases the temperature and velocity of their combustion. These time dependences are extreme, with maximum values during 180 s planetary milling. Experiments show that the reaction products consist of an aluminum matrix with uniformly distributed particles of titanium diboride of not over 1 µm in size. The average particle size changes with the increase in the time of the planetary milling of the initial powder mixture. [ABSTRACT FROM AUTHOR]

In this paper, the design of a data-rate constrained observer for a dynamical system is presented. This observer is designed to function both in discrete time and continuous time. The system is connected to a remote location via a communication channel which can transmit limited amounts of data per unit of time. The objective of the observer is to provide estimates of the state at the remote location through messages that are sent via the channel. The observer is designed such that it is robust toward losses in the communication channel. Upper bounds on the required communication rate to implement the observer are provided in terms of the upper box dimension of the state space and an upper bound on the largest singular value of the system's Jacobian. Results that provide an analytical bound on the required minimum communication rate are then presented. These bounds are obtained by using the Lyapunov dimension of the dynamical system rather than the upper box dimension in the rate. The observer is tested through simulations for the Lozi map and the Lorenz system. For the Lozi map, the Lyapunov dimension is computed. For both systems, the theoretical bounds on the communication rate are compared to the simulated rates. [ABSTRACT FROM AUTHOR]

It has been found that a high electrical conductivity of 63.1%, the International Annealed Copper Standard (IACS), and high mechanical properties are achieved by the initial aluminum alloy after undergoing four cycles of the severe plastic deformation (SPD) process. It has been found that when TiB2 particles are introduced into aluminum and the samples are subject to SPD, the mechanical characteristics of the aluminum alloy are improved. Microhardness (HV) increases from 329 to 665 MPa, yield strength (YS) increases from 38 to 103 MPa, and ultimate tensile strength (UTS) increases from 73 to 165 MPa while maintaining the initial electrical conductivity of cast aluminum without reinforcing particles (53.9–54.1% IACS). [ABSTRACT FROM AUTHOR]