This paper analyses the geomagnetic storm on September 26–29, 2011. We compare the calculation results obtained using the Global Self-consistent Model of the Thermosphere, Ionosphere and ...Protonosphere (GSM TIP) and IRI-2012 (Bilitza et al., 2014) model with ground-based ionosonde data of stations at different latitudes and longitudes. We examined physical mechanisms responsible for the formation of ionospheric effects during the main phase of geomagnetic storm that occurred at the rising phase of the 24th solar cycle. We used numerical results obtained from IRI-2012 and GSM TIP models as propagation environment for HF signals from an equatorial transmitter during quiet and disturbed conditions. We used the model of HF radio wave propagation developed in I. Kant Baltic Federal University (BFU) that is based on the geometrical optics approximation. We compared the obtained radio paths in quiet conditions and during the main and recovery storm phases and evaluated radio wave attenuation in different media models.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents the results of model calculations of the behavior of the ionosphere during a complex space-weather event that occurred in September 2017. The main attention is paid to the ...analysis of the response of an integral characteristic of the ionosphere—global electron content (GEC)—to geomagnetic storms on September 7–8. Comparison of the temporal behavior of the model and experimental GEC showed there to be a good qualitative agreement between the temporal variations of hydroelectric power stations associated with geomagnetic storms. At the same time, the absence in the results of model calculations of positive hydroelectric disturbances observed on September 7, 8, and 11 is noted. It is hypothesized that these positive disturbances of the GEC on the indicated days may be associated with the observed solar-proton events and precipitation of protons from the magnetosphere, but not taken into account in model calculations.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We examine the influence of superconductivity on the magneto-transport properties of a ferromagnetic Ni nanowire connected to Nb electrodes. We show experimentally and confirm theoretically that the ...Nb/Ni interface plays an essential role in the electron transport through the device. Just below the superconducting transition, a strong inverse proximity effect from the nanowire suppresses superconducting correlations at Nb/Ni interfaces, resulting in a conventional anisotropic magneto-resistive response. At lower temperatures however, the Nb electrodes operate as superconducting shunts. As the result, the magneto-resistance exhibits a strongly growing hysteretic behavior accompanied by a series of saw-like jumps. The latter are associated with the penetration/escape of individual Abrikosov vortices that influence non-equilibrium processes at the Nb/Ni interface. These effects should be taken into account when designing superconducting quantum nano-hybrids involving ferromagnetic nanowires.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The initial phase of a major geomagnetic storm on 14 December 2006 was selected in order to investigate the ionizing effect of energetic electrons in the ionosphere. The global network of GPS ...receivers was used to analyze the total electron content (TEC). A strong positive ionospheric storm of ~20 TEC units (TECU) with ~6 h duration was observed on the dayside during the interval of northward interplanetary magnetic field. At the same time, the NOAA/POES satellites observed long‐lasting intense fluxes of >30 keV electrons in the topside ionosphere at middle and low latitudes, including a near‐equatorial forbidden zone outside of the South Atlantic Anomaly (SAA). We found that the TEC increases overlapped well with the enhancements of energetic electrons. Modeling of the ionospheric response by using a Global Self‐consistent Model of the Thermosphere, Ionosphere, and Protonosphere, based on the standard mechanisms of plasma transport, could only partially explain the ionospheric response and was unable to predict the long‐duration increase of TEC. For the energetic electrons, we estimated the ionizing effect of ~45 TECU and ~23 TECU in the topside ionosphere, respectively, inside and outside of SAA. The ionizing effect contributed from 50% to 100% of TEC increases and provided the long duration and wide latitudinal extension of the positive ionospheric storm. This finding is a very important argument in supporting significant ionizing effect of energetic electrons in the storm time ionosphere both at middle and low latitudes.
Key Points
TEC increases in the low‐ and middle‐latitude ionosphere at the initial storm phase
Greater than 30 keV electron fluxes enhance significantly at the initial storm phase
Energetic electron enhancements produce significant ionizing effect in the ionosphere
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The modern building materials market places high demands on heat-insulating and heat-insulating structural materials. In this connection, the issues of developing high-quality building materials ...obtained on the resource-saving technologies basis allowing to solve two interrelated problems are topical. The first problem is the industrial waste generated and existing stocks disposal. The second is associated with a decrease in the traditional raw materials deficit 1. These problems solution, combining rational technological solutions, is based on the scientific research achievements in this area, in particular in the foam glass production. The priority scientific research areas in the foam glass materials production are the developments related to the study, the new raw materials use and the production of foam glass mixture compositions on their basis, which provide, along with the necessary performance properties, high environmental safety requirements 2, 3.
Understanding the principles underlying the stability and sustainability of the gut microbiome of adolescents with normal weight and obesity will make it possible to implement a personalized approach ...to the correction of metabolic disorders. The article presents the results of a pilot study of the diversity and metabolic potential of the gut microbiome in adolescents with normal body weight and obesity. Biological material was studied using metagenomic sequencing of the V3-V4 variable regions of the
16S rRNA
gene. In all adolescents with normal weight, similar degree of the phylogenetic relationship between the bacterial taxa of the community was demonstrated. In contrast, obese adolescents were characterized by the presence of phylogenetically distinct taxa in the gut microbiota. However, even with differences in taxonomic composition, the gut microbial community can compensate for the absence of certain taxonomic groups by implementing the necessary metabolic functions using other phylogenetically close taxa.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper is devoted to the relevant problem of the astronaut's emotional states identification. The latest research in this domain have revealed the tendency of the emotional state definition via ...facial expression recognition. Besides, some other technologies are applied: heartrate monitors, brain activity analyzers, speech tone recognition, etc. Nevertheless, the problem of the emotional state monitoring relates to the classification one, so, a wide range of solutions has been proposed, including artificial neural networks, K-nearest neighbors, fuzzy logic and others. The main contribution of this paper is the development of the cognitive-map based classifier. The results of testing demonstrate the robustness and the adequacy of the cognitive map proposed.
•Constant monitoring of the astronauts emotional state is a topical problem.•Cognitive maps was not used as a classifier for emotions recognition.•A cognitive map of a particular developed structure can be used as a classifier.•A complex cognitive map-based technique to monitor the astronauts emotional state is proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We apply two promising approaches, namely, the shooting method based on global optimization and the generalized force method, to the problem of point-to-point ionospheric ray tracing where the ...ionospheric modes tend to the minimum frequency. In most cases, both methods are capable of finding all rays connecting the given transmitter and receiver. However, the generalized force approach is more stable in locating highly divergent high rays. Application of the methods to a long-range single-hop radio channel demonstrates their potential for expanding the simulated frequency range, refining the model ionograms in the ranges of the minimum frequency of reflection from ionospheric layers, and significantly improving the overall forecast of the lowest usable frequency. The results of numerical simulations were also compared with the experimental data. Joint application of the presented methods provides valuable means for solving applied problems of radio communication forecast.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
It is fact that production of secondary fuel isotopes (plutonium) is carried out in fast neutron reactors, and the possibility of production of non-fuel radioactive isotopes for use in medicine and ...industry is being considered. BN-600 has a high power density in the core. This makes it possible to achieve a high rate of fission of target nuclei, which is especially important in the case of the production of radioisotopes, due to their short half-life. To meet the growing demand for isotopes, it is planned to use irradiation devices in high-power sodium fast reactors. This type of irradiation device assumes a massive production of the necessary isotopes. The paper considers the design of irradiation devices for the production of molybdenum-99 isotope in the BN reactor. The presented design of the irradiation assembly contains a moderator in order to combine the advantages of the high neutron flux inherent in fast reactors and the thermal neutron spectrum inherent in thermal reactors.
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