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Plane 3D model of hydraulic fracture propagation is implemented. Fluid flow inside the fracture, leak-of, rock deformation and breaking are taken into account. Asymptotic solution for tip of semi-infinite plane fracture is used to set boundary conditions for fluid flow problem and to calculate fracture front propagation velocity. Elastic and fluid flow equations are united in one system of nonlinear equations and solved simultaneously by Newton method with analytically calculated Jacoby matrix. The implemented model may be used as a start point for testing various methods of solution of “hydrodynamic-elasticity” problem and improving their convergence speed. Also model can be used for developed hydraulic fracture simulation.

Prediction skill of continental climate in the Northern Hemisphere (NH) midlatitudes is generally limited throughout the year in dynamical seasonal forecast systems. Such limitations narrow the range of possible applications by different stakeholders. Improving the predictive capacity in these regions has been a challenging task. Sea ice is a central component of the Arctic climate system and a local source of climate predictability, yet its state is often not fully constrained in dynamical forecast systems. Using the EC-Earth3 climate model, we study the added value of assimilating observed Arctic sea ice concentration on the NH extratropical climate in retrospective forecasts of summer and fall, initialized every spring over 1992–2019. Predictions in the North Atlantic and Eurasia benefit from better initialization of sea ice in the Atlantic sector of the Arctic in a two-step mechanism. Initially, sea ice influences the central North Atlantic Ocean through an atmospheric bridge that develops in the first forecast weeks, subsequently leading to preserved skill in the sea surface temperatures (SSTs) throughout summer and early fall. Secondly, these long-lasting SST improvements provide better surface boundary conditions for the atmosphere and lead to more skillful predictions of circulation and surface climate in the Euro-Atlantic and Asian regions. In addition, our findings suggest that fully coupled ocean-atmosphere-sea ice models are likely necessary to study linkages between Arctic sea ice and midlatitudes, by better representing the interactions and feedbacks between the different components of the climate system.

We studied olivines from the Devonian pre-trap (the Ilbokich occurrence) and the Triassic post-trap (the Chadobets occurrence) carbonate-rich ultramafic lamprophyres (UMLs) in the southwestern portion of the Siberian craton. On the basis of detailed investigations of major, minor, and trace-element distributions, we have reconstructed the main processes that control the origins of these olivines. These include fractional crystallisation from melt, assimilation, and fractional crystallisation processes with orthopyroxene assimilation, melt-reaction diffusive re-equilibration, alkali enrichment, and CO2 degassing of the melt. Furthermore, we inferred the composition of the sources of the primary UML melt and their possible correlations with proto-kimberlitic melts, as well as the influence of the Triassic Siberian plume on the composition of the lithospheric mantle. The main differences between olivines from the Ilbokich and the Chadobets aillikites were that the olivines from the former had more magnesium-rich cores (Mg# = 89.2 ± 0.2), had Mg- and Cr-rich transition zones (Mg# = 89.7 ± 0.2 and 300–500 ppm Cr), had lower Ni (up to 3100 ppm) and Li (1.4–1.5 ppm), and had higher B (0.8–2.6 ppm) contents, all at higher Fo values (90–86), relative to the olivines from the latter (Mg# = 88–75; 200–300 ppm Cr; up to 3400 ppm Ni; 1.4–2.4 ppm Li; 0.4–2.2 ppm B). The Siberian aillikite sources contained a significant amount of metasomatic material. Phlogopite-rich MARID-type veins provided the likely metasomatic component in the pre-trap Devonian Ilbokich aillikite source, whereas the Triassic Chadobets aillikitic post-trap melts were derived from a source with a significant carbonate component. A comparison of UML olivines with olivines from the pre-trap and post-trap Siberian kimberlites shows a striking similarity. This suggests that the carbonate component in the aillikitic source could have been produced by evolved kimberlite melts. The differences in the lithospheric metasomatic component that contributed to pre-trap and post-trap aillikitic melts can be interpreted as reflections of the thermal impact of the Siberian Traps, which reduced phlogopite-bearing metasomes within the southwestern Siberian sub-continental lithospheric mantle.

Instrumental records of two earthquakes with foci in the Almaty territory were obtained, recorded during one month on February 02, 2018, and February 15, 2018. The local seismic events registered in February 2018 in the Almaty territory are analyzed. These are 2 – 4 magnitude earthquakes with foci on the city’s territory. Using the AT 1105 sensors and the RSM-8 recorder, station No. 1 “Institute” recorded instrumental readings of accelerations in the basement and the four-story frame-brick building roof. For the first time, an instrumental recording was obtained, on which two groups of waves were identified. Spectral curves β are plotted. Effective duration is insignificant 0.12 – 1.74 sec. New results have been obtained regarding the behavior of a building under the influence of two earthquakes of different intensities. The absence of significant values of the spectral curves of the two earthquakes was noted. There is an increase in the intensity and number of local earthquakes in 2018 compared to 2007 – 2014. The results can be used to design earthquake-resistant buildings, taking into account the requirements of Eurocode 8.

During the earthquake on March 26, 2018 with a source in the Almaty region, the stations of the engineering and seismometric service received instrumental records on buildings with various design solutions. The article discusses instrumental records (accelerograms) recorded on a four-storey frame building and an 11-storey building with a steel frame. Spectral curves were plotted at the registration points on the roof and basement parts of buildings. It was found that the periods of the prevailing fluctuations of the base of the structure are 0.16-0.21 sec for the two indicated buildings. The spectral curves at the basement level have the same shape. Instrumental records are included in the database of accelerograms of KazRDICA JSC.

Using probabilistic methods, the reliability and seismic resistance of a large-panel building on kinematic foundations (KF) at the seismic isolation site in Almaty is analyzed. The building is modeled by a nonlinear single-mass system with an experimental deformation diagram. Seismic impact is modeled by a random process with a given correlation function. To calculate probabilistic characteristics, the method of statistical tests is used (Monte-Carlo method). The seismic impact parameters are set in accordance with the \"Map of the seismic zoning of the Republic of Kazakhstan\" by the median values of peak accelerations. 2 accelerograms of the 1990 Baysorun earthquake were chosen as the impact model. Therefore, these accelerograms were taken as the basis for modeling the seismic effects of a random process. Generation of realizations of a stationary random process is performed by recursive filtering. The influence of the number of statistical tests (artificial accelerograms) on the accuracy of calculating the moments of the distribution function of displacements was investigated. According to the results of a Monte Carlo calculation using 5000 realizations, the reliability of the building is determined (probability of failure-free operation). Conclusions about system effectiveness of seismoisolation of kinematic type for the influence specified like buildings at regional parameters are drawn.

We consider thin liquid films on the inside (rimming flows) or outside (coating flows) of a cylinder with horizontal axis, rotating about this axis. If the liquid’s net volume is small, such films are known to evolve towards a steady state with a smooth surface, whereas, for larger amounts, the flow develops a ‘shock’ similar to a tidal bore. In this work, smooth films are shown to be unstable. Since the strongest instability occurs at wavelengths comparable to the film’s thickness, our analysis is based on the full Navier–Stokes equations, not on the lubrication approximation (which has been traditionally used in this problem). It is also shown that, for cylinders of sufficiently small radii, the instability can be suppressed by surface tension.

We consider generation of radiation with a comb spectrum in a ring fiber cavity with harmonic mode locking provided by dissipative four-wave mixing. The main element of the laser system cavity is an amplifying one-dimensional photonic crystal, which combines the properties of an intracavity filter and a power amplifier. Using standard propagation equations describing signal conversion in a ring cavity and an output fiber stage, we demonstrate a possibility of employing the proposed model as a broadband frequency comb generator with a controlled repetition rate of generated signals.

To assess changes in the dynamic characteristics of the 25-storeyed building of the Kazakhstan Hotel in Almaty, an analysis of instrumental records of the station of engineering seismometric service was carried out. The building is located near the tectonic fault. During two earthquakes, representative instrumental data were obtained at the Seismic Station No. 16 (\"High-rise Hotel\"), equipped with digital instrumentation and measurement system. The building is twenty-five-storeyed with a stiffening core, built in 1976. Using the ADXL accelerometers and the RSM-32 recorder, high-quality instrumental records of accelerations were obtained in the basement, on the floors and on the roof of the building, and spectral curves β were also built. The peculiar features of the dynamics of the specified building are noted during earthquakes. Periods of the building oscillation on the main and second modes of oscillation were revealed on exposure to a remote earthquake. Comparison of the dynamic characteristics of the house was carried out according to the measurements of 1977 and 2018. It has been established that there is a significant increase in the magnitude of the oscillation period on the first form by 25-48% as compared to the measurements of 1976-1977 over the 40-year period of operation.

The range of stable operation of a Francis turbine is restricted by unsteady phenomena observed in the draft tube at high load and part load operating conditions. At part load, the pressure pulsations are caused by the rotation of the helical vortex rope in the draft tube. The aim of this investigation is to develop the methodology for minimizing part load pressure pulsations through the optimization of the runner shape. The main challenge here is the high computational cost of unsteady CFD analysis required to evaluate the amplitude of pressure pulsations. The obvious idea to overcome this problem suggests performing CFD analysis in steady state and estimating pulsation characteristics indirectly based on the computed velocity profile downstream of the runner. However this approach raises the second problem: finding a correlation between the velocity profile and the corresponding amplitude of draft tube pressure pulsations. To avoid trivial but unacceptable solutions such as “the less swirl, the smaller the pulsations”, we need to focus only on those velocity profiles, that can be realized at part load by high efficiency runners, meeting power and efficiency requirements at other operating points (BEP, full load, etc.). To generate such a set of admissible part load velocity profiles, we propose solving an auxiliary multi-point optimization problem. Once the set of admissible profiles is found, the desired correlation can be determined using unsteady CFD analysis for several dozen selected geometry variants. This paper discusses the preliminary results obtained during the practical implementation of the above approach.