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The high-resolution Fourier diffractometer (HRFD) operates at the IBR-2 pulsed reactor, on which the correlation method of data registering has been implemented using a fast Fourier chopper and specialized electronics. A wide-aperture ring back-scattering detector for HRFD has been developed. The detector consists of six Z n S ( A g ) / 6 L i F-scintillation rings, each one of which is divided into 12 sections. Main parameters of this detector: covered solid angle 2 θ = ( 133 − 175 ) ∘ ; Ω d ≈ 2.0 sr; average absorption efficiency 85 %, geometric contribution to resolution Δ d / d < 0.0005. The concept of a detector and its data acquisition system are presented.

To investigate the possibility of preparation of a surfacing powder for gas-plasma facing, mechanochemical alloying of a mixture of Fe, Ni, Cr, Cu, B, and C powders is performed in a MPP-2-1K planetary mill for 15 min. To determine the chemical interaction between charge components and the sequence and character of formation of the phase composition in granulated alloys during mechanochemical alloying (MCA), X-ray diffraction (XRD) analysis of the powder material is performed using a D8 ADVANCE (BrukerElementalGmbH) diffractometer. The morphology of granules after mechanical alloying is studied by scanning electron microscopy (SEM) using a JEOLJXA-8230 scanning electron microscope. To determine the melting temperature of the prepared composition, thermal gravimetric analysis is carried out using a TG-DTA/DSC STA 449 F3 Jupiter (NETZSCH) synchronous thermal analyzer equipped with a quadrupole mass spectrometer. The experimental results of show that, upon mechanical activation of an Fe–Ni–Cr–Cu–Si–B–C composition, the formation of both stable and metastable phases takes place. It is found that, already after 1-min mechanochemical alloying, numerous new phases form; after 15-min alloying, a multiphase system forms, which includes intermetallics (Fe0.95Ni0.05, Cr1.07Fe18.93, etc.), carbides (Fe3C, Cr15.58Fe7.42C6, etc.), borides (Ni75Si24B0.04, etc.), and silicides (Ni0.92Si0.08, Cr5Si3). The main cause for the phase formation upon mechanochemical alloying is the shock action of milling bodies (balls), which results in the plastic deformation of starting component particles, their breaking, and welding along formed juvenile surfaces, which is accompanied by exothermic effects and the formation of intermediate liquid phases. As a result, the contact surface of the reagents abruptly increases and composite particles form. Upon shock action, complex and poorly understood chemical processes, diffusion of components, and phase- and structure-formation occur.

At the oil production wells of Gazpromneft Vostok LLC, with the problem of scale formation, there was made an assessment of the possibility of using an encapsulated scale inhibitor. According to the test results, it’s found that the reagent provides effective protection of production wells from salt deposits. There are noted such a positive aspects of this inhibitory protection technology as the absence of corrosive effects on downhole equipment, the possibility of quick organization of well protection, not using metering equipment, independence from the infrastructure and the convenience of loading capsules during workover. A comparative analysis with the classical inhibitor protection with liquid scale inhibitors has been carried out. It is shown that with a water flow rate of up to 38 m3 / day, the use of encapsulated reagents is more cost effective. The limitations of the application of the technology are noted – the difficulty in carrying out additional loading of the reagent into the well without lifting the downhole equipment, application in horizontal and directional wells.

—In 2015–2017, attendance of 15 invasive and 22 native species of herbaceous plants by ants was studied in 6 habitats in the environs of Kyiv (Ukraine). Altogether, 14 ant species were found, of which 12 were recorded on invasive plants and 9 on native plants; 8 aphid species were found on 8 invasive plant species. Five invasive plant species (Asclepias syriaca, Heracleum mantegazzianum, Oenothera biennis, Onopordum acanthium, and Amaranthus retroflexus) were found to be attractive to ants, with over a half of all the ant workers in all the habitats being recorded on them; besides, numerous colonies of 7 aphid species were also found on these plants. These invasive plants positively affect the structure of ant assemblages since the aphid colonies provide ants with food resource. The remaining 10 invasive plant species, including 5 transformer species, were poorly visited by ants and housed no aphid colonies, with the exception of Conyza canadensis on which the non-myrmecophilous aphid Uroleucon erigeronense (Thomas, 1878) was found. Two thirds of invasive plant species had a negative effect on the structure of ant assemblages because they replaced the native plants and thus reduced the trophic resources of aphids.

Damping of the previously discovered resonant drag instability (RDI) of dust streaming in protoplanetary disc is studied using the local approach to dynamics of gas-dust perturbations in the limit of the small dust fraction. Turbulence in a disc is represented by the effective viscosity and diffusivity in equations of motion for gas and dust, respectively. In the standard case of the Schmidt number (ratio of the effective viscosity to diffusivity) Sc = 1, the reduced description of RDI in terms of the inertial wave (IW) and the streaming dust wave (SDW) falling in resonance with each other reveals that damping solution differs from the inviscid solution simply by adding the characteristic damping frequency to its growth rate. RDI is fully suppressed at the threshold viscosity, which is estimated analytically, first, for radial drift, next, for vertical settling of dust, and at last, in the case of settling combined with radial drift of the dust. In the last case, RDI survives up to the highest threshold viscosity, with a greater excess for smaller solids. Once Sc \neq 1, a new instability specific for dissipative perturbations on the dust settling background emerges. This instability of the quasi-resonant nature is referred to as settling viscous instability (SVI). The mode akin to SDW (IW) becomes growing in a region of long waves provided that Sc > 1 (Sc < 1). SVI leads to an additional increase of the threshold viscosity., Accepted for publication in MNRAS

The Olympiada deposit, containing >1,560 metric tons (t; 50 Moz) of gold at an average grade of 4 to 4.6 g/t Au, occurs in central Siberia, Russia. Over 30 years, the deposit produced more than 580 t of gold, including 200 t from oxidized ore grading 11.1 g/t. The deposit forms a 2-km-long, steeply dipping system, which is traced downdip for 1.7 km. It occurs in the Neoproterozoic orogen of the Yenisei Ridge at the western margin of the Siberian craton. This and other gold deposits in the district are controlled by the large, long-lived Tatarka-Ishimbino tectonic zone, marking a suture between terranes chiefly consisting of deformed Meso- to Neoproterozoic carbonate-clastic sedimentary rocks. The combination of lithologic and structural factors was critical for localization of gold mineralization associated with calcic and siliceous alteration accompanied by early arsenic and late antimony sulfides. As a result, very fine (10 μm) and high fineness (910–997) gold associates with diverse sulfides, especially arsenopyrite, and commonly contains mercury, similar to some characteristics of Carlin-type deposits. Geochronologic studies suggest that mineralization was formed during several stages between 817 and 660 Ma. The isotopic composition of Os and He, along with presence of anomalous Ni, Co, and Pt, points to a mantle mafic source, whereas isotopic composition of Pb and S suggest a contaminated crustal source, i.e., originating from a mix of mantle and crustal fluids.

Dust is the usual minor component of the interstellar medium. Its dynamic role in the contraction of the diffuse gas into molecular clouds is commonly assumed to be negligible because of the small mass fraction, $f \simeq 0.01$. However, as shown in this study, the collective motion of dust grains with respect to the gas may considerably contribute to the destabilisation of the medium on scales $\lambda \lesssim \lambda_J$, where $\lambda_J$ is the Jeans length-scale. The linear perturbations of the uniform self-gravitating gas at rest are marginally stable at $\lambda \simeq \lambda_J$, but as soon as the drift of grains is taken into account, they begin growing at a rate approximately equal to $(f \tau)^{1/3} t^{-1}_{ff}$, where $\tau$ is the stopping time of grains expressed in units of the free fall time of the cloud, $t_{ff}$. The physical mechanism responsible for such a weak dependence of the growth rate on $f$ is the resonance of heavy sound waves stopped by the self-gravity of gas with weak gravitational attraction caused by perturbations of the dust fraction. Once there is stationary subsonic bulk drift of the dust, the growing gas-dust perturbations at $\lambda < \lambda_J$ become waves propagating with the drift velocity projected onto the wavevector. Their growth has a resonant nature as well and the growth rate is substantially larger than that of the recently discovered resonant instability of gas-dust mixture in the absence of self-gravity. The new instabilities can facilitate gravitational contraction of cold interstellar gas into clouds and additionally produce dusty domains of sub-Jeans size at different stages of molecular cloud formation and evolution., Comment: 19 pages, 7 figures; accepted for publication in MNRAS

Analysis of the literature data on the properties of high-entropy alloys based on the Al-Cr-Mn-Fe system was performed. The results allowed evaluating the prospects for the synthesis of high-entropy alloys in Al-Cr-Mn-Fe-(Ti, Zr, V, Nb, Ta) systems. The results of modeling the Al-Ti-Cr-Mn-Fe alloy by ab initio molecular dynamics showed that the formation of a high-entropy alloy is possible. In this alloy, both in terms of partial pair functions of the radial distribution and analysis of the size of atoms, an ordered solid solution can be formed. After analyzing the data obtained from the calculations, we can assume a high probability of formation of intermetallides Al-Ti, Mn-Ti, Fe-Ti and Fe-Al.

The recently discovered resonant drag instability (RDI) of dust streaming in protoplanetary disc is considered as the mode coupling of subsonic gas-dust mixture perturbations. This mode coupling is coalescence of two modes with nearly equal phase velocities: inertial wave (IW) having positive energy and a streaming dust wave (SDW) having negative energy as measured in the frame of gas environment being at rest in vertical hydrostatic equilibrium. SDW is a trivial mode produced by the bulk streaming of dust, which transports perturbations of dust density. In this way, settling combined with radial drift of the dust makes possible coupling of SDW with IW and the onset of the instability. In accordance with the concept of the mode coupling, RDI growth rate is proportional to the square root of the coupling term of the dispersion equation, which itself is proportional to mass fraction of dust, $f\ll 1$. This clarifies why RDI growth rate $\propto f^{1/2}$. When SDW has positive energy, its resonance with IW provides an avoided crossing instead of the mode coupling. In the high wavenumber limit RDI with unbounded growth rate $\propto f^{1/3}$ is explained by the triple mode coupling, which is coupling of SDW with two IW. It coexists with a new quasi-resonant instability accompanied by bonding of two oppositely propagating low-frequency IW. The mode coupling does not exist for dust streaming only radially in a disc. In this case RDI is provided by the obscured mechanism associated with the inertia of solids., 19 pages, 8 figures; substantially extended version of arXiv:1903.12492

Planet migration originally refers to protoplanetary disks, which are more massive and dense than typical accretion disks in binary systems. We study planet migration in an accretion disk in a binary system consisting of a solar-like star hosting a planet and a red giant donor star. The accretion disk is fed by a stellar wind. %, disk self-gravity is neglected. We use the $\alpha$-disk model and consider that the stellar wind is time-dependent. Assuming the disk is quasi-stationary we calculate its temperature and surface density profiles. In addition to the standard disk model, when matter is captured by the disk at its outer edge, we study the situation when the stellar wind delivers matter on the whole disc surface inside the accretion radius with the rate depending on distance from the central star. Implying that a planet experiences classical type I/II migration we calculate migration time for a planet on a circular orbit coplanar with the disk. Potentially, rapid inward planet migration can result in a planet-star merger which can be accompanied by an optical or/and UV/X-ray transient. We calculate timescale of migration for different parameters of planets and binaries. Our results demonstrate that planets can fall on their host stars within the lifetime of the late-type donor for realistic sets of parameters., Comment: 10 pages, 6 figures; Subm. to MNRAS

A specialized diffractometer intended for use in studying real-time transient processes in condensed media, which also allows the recording of Bragg diffraction and small-angle neutron scattering spectra, has been created at the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research. Frequently, only the given formulation of the experiment with the continuous recording of information on the process enables us to obtain data required for the correct interpretation of events. One of the crucial parameters of such experiments is the minimal time interval in which sufficient statistics can be acquired. The diffractometer parameters make it possible to measure diffraction and small-angle spectra within minute and even second (for certain types of transition processes) ranges. The possibilities of neutron scattering are discussed as applied to the study of transient processes, the diffractometer design is described, and its main characteristics and the test experiment results are presented.

A twisted disc forms around a rotating black hole each time when the disc outskirts are not aligned with the black hole’s equatorial plane. We derive equations describing the evolution of the shape of twisted discs and perturbations of density and velocity necessarily arising in such a disc. This is done under the following simplifying assumptions: a small aspect ratio of the disc, a slow rotation of the black hole, and a small tilt angle of the disc rings with respect to the black hole equatorial plane. Nevertheless, the GR effects are considered accurately. Additionally, an analysis of particular regimes of non-stationary twist dynamics (the wave and diffusion regimes) is presented both in the framework of the Newtonian dynamics and taking into account Einstein’s relativistic precession. At the end of the chapter, a calculation of the shape of a stationary relativistic twisted accretion disc for different values of free parameters of the model is done.

In this chapter we present a model of a standard accretion disc around a rotating black hole taking general relativity effects into full account. This model was first described in the paper by Novikov and Thorne (Black holes (Les Astres Occlus). Gordon and Breach, New York, 1973) and has since then been used in many studies to obtain convincing evidence of the existence of black holes, in both stellar binary systems and active galactic nuclei. It remains topical since a full account of the general relativistic properties of the motion of matter in the disc, and the generation of disc emission, allows the position of the inner disc radius and hence the black hole spin to be inferred from observations. In addition, the standard accretion disc is the basis for more complicated theories of warped (twisted) accretion discs, which are formed when the accreting matter moves outside the equatorial plane of a rotating black hole.

The focusing properties of a linear radio-frequency (RF) electric field and the results of their use for time-of-flight mass separation of polyenergetic ions are considered. A method for forming 2D linear RF fields by planar discrete electrodes with multiple distributed capacitive voltage dividers is proposed. An experimental prototype of an RF mass reflectron with planar discrete electrodes was created and investigated. The results of analytical calculations, computer simulations, and experiments are presented.

We present not a literature review but a description, as detailed and consistent as possible, of two analytic models of disk accretion onto a rotating black hole: a standard relativistic disk and a twisted relativistic disk. Although one of these models is much older than the other, both are of topical current interest for black hole studies. The way the exposition is presented, the reader with only a limited knowledge of general relativity and relativistic hydrodynamics can --- with little or no use of additional sources -- gain good insight into many technical details lacking in the original papers., 65 pages, 3 figures, published in Physics-Uspekhi. http://ufn.ru/en/articles/2015/6/a

Turbulent state of spectrally stable shear flows may be developed and sustained according to the bypass scenario of transition. If it works in non-magnetised boundless and homogeneous quasi-Keplerian flow, transiently growing shearing vortices should supply turbulence with energy. Employing the large shearing box approximation, as well as a set of global disc models, we study the optimal growth of the shearing vortices in such a flow in the whole range of azimuthal length-scales, $\lambda_y$, as compared to the flow scale-height, $H$. It is shown that with the account of the viscosity the highest possible amplification of shearing vortices, $G_{max}$, attains maximum at $\lambda_y\lesssim H$ and declines towards both the large scales $\lambda_y\gg H$ and the small scales $\lambda_y\ll H$ in a good agreement with analytical estimations based on balanced solutions. We pay main attention to the large-scale vortices $\lambda_y\gg H$, which produce $G_{max}\propto (\Omega/\kappa)^4$, where $\Omega$ and $\kappa$ denote local rotational and epicyclic frequencies, respectively. It is demonstrated that the large-scale vortices acquire high density perturbation as they approach the instant of swing. At the same time, their growth is not affected by bulk viscosity. We check that $G_{max}$ obtained globally is comparable to its local counterpart and the shape and localisation of global optimal vortices can be explained in terms of the local approach. The obtained results allow us to suggest that the critical Reynolds number of subcritical transition to turbulence in quasi-Keplerian flow, as well as the corresponding turbulent effective azimuthal stress should substantially depend on shear rate., Comment: Accepted for publication in MNRAS

The concept of pseudopotential is used to study the ion trajectories in a superposition of uniform static and linear high-frequency electric fields. An ion-optical system is developed to generate a combination of electric fields with different spatial and temporal distributions of potentials. It is demonstrated that such systems can be used as ion traps with spatial confinement in a single quadrant or half plane in the Fouriertransform mass-spectrometers.

The processing of liquid steelmaking slags to obtain a commercial product with specified properties and maximum iron extraction is considered. The performance of existing systems for liquid-phase reduction of the metal from slag and methods of liquid-slag processing is compared. Prototype equipment for slag processing is developed and tested at OAO OMK-Stal’ (Vyksa) on liquid electrofurnace slag and ladle (refining) slag.

Results of investigations into strengthening the nickel host in the diamond composite electrochemical coating (DCEC) with nanodispersed particles are reflected. Diamond nanopowders of the detonation synthesis, which were introduced into the DCEC through the electrolyte, are applied as the strengthening phase. As a result, the microhardness of the nickel host increased by a factor of 3, while the durability of tubular drilling tools after the deposition of the diamond coating increased by a factor of 4. The developed technology can be used when producing a diamond tool for cutting stone, glass, and ceramic materials, as well as to produce correcting tools.

A new gaseous annular sectional thermal-neutron detector for the new neutron diffractometer at the IBR-2 reactor has been designed and manufactured at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research (JINR). The detector is designed to study small-volume samples at high pressure and consists of 16 sections, each one of which is divided into six independent detector elements. We present the main design features of the detector, detecting electronics, data-acquisition and visualization software, and software system for experiment management. The results of the first neutronographic experiments that were carried out with the use of the detector are also presented.

The modernization of the detector system and control system of the neutron powder diffractometer (NPD) in the GEK-5 channel of the VVR-c reactor (Obninsk Branch, Karpov Institute of Physical Chemistry) is described. The PC-connected hardware and software complex, which ensures data acquisition and storage and control of the experiments, is created. The main modules of the NPD automation system and Sonix+ control software package, designed at the Frank Laboratory of Neutron Physics at JINR, are briefly described. The modernization has made it possible to increase the luminosity of the diffractometer and completely automatize the measurement process.

Physical modeling of the high-temperature cooling and solidification of slag melt that is penetrating into spherical packing permits assessment of the thermal and physical parameters of the slag as it cools in the spaces between the spheres. The chemical and phase composition of the broken slag is investigated, and its physicomechanical characteristics are determined. The data obtained permit the development of systems to convert slag melt to gravel and inert filler for concrete.

A thin gaseous disk with a nearly Keplerian rotation profile and free boundaries in the external gravitational field of a point gravitating object does not generate any growing perturbation eigenmodes. In spite of this, a significant transient growth of linear perturbations measured by the evolution of their total acoustic energy is possible in such a disk. This is shown within the framework of the simplest model of an inviscid polytropic thin disk with a finite radial extent in which small adiabatic perturbations that are a linear combination of neutral eigenmodes with a corotation radius beyond the outer flow boundary are considered.

In this paper we derive equations describing the dynamics and stationary configurations of a twisted fully relativistic thin accretion disc around a slowly rotating black hole. We assume that the inclination angle of the disc is small and that the standard relativistic generalization of the α model of accretion discs is valid when the disc is flat. We find that similar to the case of non-relativistic twisted discs the disc dynamics and stationary shapes can be determined by a pair of equations formulated for two complex variables describing the orientation of the disc rings and velocity perturbations induced by the twist. We analyse analytically and numerically the shapes of stationary twisted configurations of accretion discs having non-zero inclinations with respect to the black hole equatorial plane at large distances r from the black hole. It is shown that the stationary configurations depend on two parameters – the viscosity parameter α and the parameter , where δ* is the opening angle (δ*∼h/r, where h is the disc half-thickness and r is large) of a flat disc and a is the black hole rotational parameter. When a > 0 and the shapes depend drastically on the value of α. When α is small the disc inclination angle oscillates with radius with amplitude and radial frequency of the oscillations dramatically increasing towards the last stable orbit, Rms. When α has a moderately small value the oscillations do not take place but the disc does not align with the equatorial plane at small radii. The disc inclination angle either is increasing towards Rms or exhibits a non-monotonic dependence on the radial coordinate. Finally, when α is sufficiently large the disc aligns with the equatorial plane at small radii. When a < 0 the disc aligns with the equatorial plane for all values of α. The results reported here may have implications for determining the structure and variability of accretion discs close to Rms as well as for modelling of emission spectra coming from different sources, which are supposed to contain black holes.

A vertically loaded shaft cryostat based on a closed-cycle cryocooler built around a Sumitomo SRP-062B pulse tube has been developed. The cryostat is intended for investigating the structure and phase transformations of materials via neutron diffraction experiments on samples at pressures up to 10 GPa created in high-pressure chambers with sapphire and diamond an vils in the temperature range of 6—300 K. The cryostat has been tested with the help of the DISK diffractometer of the Russian Research Centre Kurchatov Institute. A high-pressure chamber is loaded into the cryostat through its shaft with the help of an insert. The chamber is cooled by heat-exchange gas (helium-4) an d a heat exchanger that is thermally connected with the cryocooler’s second stage. The minimum attained temperature of a sample is 6 K. The drift diameter of the shaft is 120 mm, making it possible to cool chambers with lengths up to 200 mm (in the vertical orientation) and 110 mm (in the horizontal orientation). The cryostat has been designed and manufactured at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research.

The Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research is one of the leading centers of neutron research in Russia. Within the works on the modernization of detector systems, researchers of the laboratory have designed and fabricated linear and area gas-filled position-sensitive detectors of thermal neutrons and the area monitor detector with a low attenuation of the incoming beam. These devices and their main characteristics have been described.

The dynamics of small global perturbations in the form of a linear combination of a finite number of non-axisymmetric eigenmodes is studied in the two-dimensional approximation. The background flow is assumed to be an axisymmetric perfect fluid with adiabatic index γ = 5/3 rotating with a power law angular velocity distribution Γ ∝ r–q, 1.5 < q < 2.0, confined by free boundaries in the radial direction. The substantial transient growth of acoustic energy of optimized perturbations is discovered. An optimal energy growth G is calculated numerically for a variety of parameters. Its value depends essentially on the perturbation azimuthal wavenumber m and increases for higher values of m. The closer the rotation profile to the Keplerian law, the larger growth factors can be obtained but over a longer time. The highest acoustic energy increase found numerically is of order ∼102 over ∼6 typical Keplerian periods. Slow neutral eigenmodes with corotation radius beyond the outer boundary mostly contribute to the transient growth. The revealed linear temporal behaviour of perturbations may play an important role in angular momentum transfer in toroidal flows near compact relativistic objects (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Development of new high-flux-intensity neutron sources and the need to equip them with efficient spectrometers raises the problem of designing special-purpose direct-beam monitors-detectors. These detectors feature an extremely low efficiency and a very low attenuation of the incident neutron beam. In this work, a two-coordinate position-sensitive monitor-detector is described that was developed for real-time recording of the profile of neutron beams generated by both steady and pulsed neutron sources. The basic parameters of this device are the following: a coordinate resolution of 4 × 4 mm2, a sensitive area of 100 × 100 mm2, and a recording efficiency of 10−6−10−2. Use of nitrogen as a converter makes it possible to achieve a record low efficiency and still maintain other parameters at a desired level. The device can be combined not only with high-flux-intensity neutron sources already in use worldwide but also with next-generation sources being developed in the United States (SNS) and Japan (JPARC).

A one-dimensional position-sensitive detector of thermal neutrons has been developed to equip high-efficiency neutron spectrometers at the ИБР-2 research reactor. The detector is based on a multiwire proportional chamber filled with a mixture of 3He + CF4 and has an active area of 200 × 80 mm and a spatial resolution of 2 mm. The detector has been used to good effect in the REFLEX and HRFD spectrometers of the ИБР-2 reactor, as well as in the diffraction facility of the ИВВ-2M research reactor (Zarechnyi, Russia).

The instability of axisymmetric flows of inviscid compressible fluid with respect to two-dimensional infinitesimal perturbations with the nonconservation of angular momentum is investigated by numerically integrating the differential equations of hydrodynamics. The compressibility is taken into account for a homentropic flow with an adiabatic index varying over a wide range. The problem has been solved for two angular velocity profiles of an initial axisymmetric flow. In the first case, a power-law rotation profile with a finite enthalpy gradient at the flow edges has been specified. For this angular velocity profile, we show that the instability of sonic and surface gravity modes in a nearly Keplerian flow, when a radially variable vorticity exists in the main flow, can be explained by the combined action of the Landau mechanism and mode coupling. We also show that including a radially variable vorticity makes the limiting exponent in the rotation law at which the unstable surface gravity modes vanish dependent on the fluid compressibility. In the second case, a Keplerian rotation law with a quasi-sinusoidal deviation has been specified in such a way that the enthalpy gradient vanished at the flow edges. We have found than the sonic modes are then stabilized and the flow is unstable only with respect to the perturbations that also exist in an incompressible fluid.

This paper reviews some aspects of one of the major unsolved problems in understanding astrophysical (in particular, accretion) disks: whether the disk interiors may be effectively viscous in spite of the absence of marnetorotational instability? In this case a rotational homogeneous inviscid flow with a Keplerian angular velocity profile is spectrally stable, making the transient growth of perturbations a candidate mechanism for energy transfer from the regular motion to perturbations. Transient perturbations differ qualitatively from perturbation modes and can grow substantially in shear flows due to the nonnormality of their dynamical evolution operator. Since the eigenvectors of this operator, alias perturbation modes, are mutually nonorthogonal, they can mutually interfere, resulting in the transient growth of their linear combinations. Physically, a growing transient perturbation is a leading spiral whose branches are shrunk as a result of the differential rotation of the flow. This paper discusses in detail the transient growth of vortex shear harmonics in the spatially local limit as well as methods for identifying the optimal (fastest growth) perturbations. Special attention is given to obtaining such solutions variationally, by integrating the direct and adjoint equations forward and backward in time, respectively. The material is presented in a newcomer-friendly style., 66 pages, 11 figures, published in Physics-Uspekhi. http://ufn.ru/en/articles/2015/11/a/

Patient monitoring during mechanotherapy based on electrocutaneous impedance measurement is discussed. Methods implemented by the Alpharhythmica computer-assisted system are described. Mechanotherapy modifies electrocutaneous impedance as compared to other parameters: heart rate, arterial pressure, and body temperature. Real time criteria of mechanotherapy efficacy based on electrocutaneous impedance measurement are suggested. Results of electrocutaneous impedance monitoring are presented.

We study linear transient dynamics in a thin Keplerian disc employing a method based on variational formulation of optimisation problem. It is shown that in a shearing sheet approximation due to a prominent excitation of density waves by vortices the most rapidly growing shearing harmonic has azimuthal wavelength, $\lambda_y$, of order of the disc thickness, $H$, and its initial shape is always nearly identical to a vortex having the same potential vorticity. Also, in the limit $\lambda_y\gg H$ the optimal growth $G\propto (\Omega/\kappa)^4$, where $\Omega$ and $\kappa$ stand for local rotational and epicyclic frequencies, respectively, what suggests that transient growth of large scale vortices can be much stronger in areas with non-Keplerian rotation, e.g. in the inner parts of relativistic discs around the black holes. We estimate that if disc is already in a turbulent state with effective viscosity given by the Shakura parameter $\alpha\lambda_y>H$ have the most favourable conditions to be transiently amplified before they are damped. At the same time, turbulence is a natural source of the potential vorticity for this transient activity. We extend our study to a global spatial scale showing that global perturbations with azimuthal wavelengths more than an order of magnitude greater than the disc thickness still are able to attain the growth of dozens of times in a few Keplerian periods at the inner boundary of disc., Comment: 21 pages, 10 figures, accepted for publication in MNRAS

AIM. To study changes in the plasma concentration of beta-endorphin (beta-E) in patients with hemophilia A and B (in the presence of bleeding and in the absence of hemorrhagic syndrome) and in whole blood and plasma donors before and after donation and to investigate the factors associated with (beta-E) concentration changes.The prospective study of beta-E concentration changes (and related factors) enrolled 38 persons: 12 patients with hemophilia after acute blood loss, 11 patients with hemophilia without hemorrhagic syndrome, and 15 whole blood and plasma donors. beta-E concentrations were measured by enzyme immunoassay.In blood loss, the patients with hemophilia were found to have elevated serum beta-E concentration: 9.6 pg/ml (95% confidence interval (CI), 6.1 to 13.0 pg/ml) versus 5.2 pg/ml (95% CI, 1.4 to 8.9 pg/ml). After donation, the concentration of 3-E in the group of donors was higher than before donation: 7.3 pg/ml (95% CI, 4.9 to 9.7 pg/ml) versus 4.7 pg/ml (95% CI, 3.2 to 6.3 pg/ml). In the group of patients with hemophilia, the elevation of 3-E concentrations is steady-state (lasted at least 10 days); at this time, the beta-E value variability (estimated by mean square deviation) increased as compared with that in remission: 7.7 pg/ml (95% CI, 5.5 to 13.1 pg/ml) versus 2.4 pg/ml (95% CI, 1.7 to 4.4 pg/ml). The above differences are statistically significant (p = 0.05).In blood loss, there is an increase in plasma beta-E concentrations in the patients with hemophilia and donors. The increase in beta-E concentrations and the variability of its values were greater in the patients with hemophilia and blood loss than in the donors. The beta-E concentration elevation accompanying hemorrhage is characterized by steadiness in the patients with hemophilia.

This paper presents our latest numerical simulations of accretion disks that are misaligned with respect to the rotation axis of a Kerr black hole. In this work we use a new, fully conservative version of the Cosmos++ general relativistic magnetohydrodynamics (GRMHD) code, coupled with an ad hoc cooling function designed to control the thickness of the disk. Together these allow us to simulate the thinnest tilted accretion disks ever using a GRMHD code. In this way, we are able to probe the regime where the dimensionless stress and scale height of the disk become comparable. We present results for both prograde and retrograde cases. The simulated prograde tilted disk shows no sign of Bardeen-Petterson alignment even in the innermost parts of the disk. The simulated retrograde tilted disk, however, does show modest alignment. The implication of these results is that the parameter space associated with Bardeen-Petterson alignment for prograde disks may be rather small, only including very thin disks. Unlike our previous work, we find no evidence for standing shocks in our simulated tilted disks. We ascribe this to the combination of small black hole spin, small tilt angle, and small disk scale height in these simulations. We also add to the growing body of literature pointing out that the turbulence driven by the magnetorotational instability in global simulations of accretion disks is not isotropic. Finally, we provide a comparison between our moderately thin, untilted reference simulation and other numerical simulations of thin disks in the literature., Comment: 13 pages, 14 figures, accepted to Astrophysical Journal

As many as 8 autologic transplantations of the bone marow are performed: 5 patients with hemoblastoses, 1 patient with lymphogranulomatosis and 2 patients with great tumors. The bone marrow is preserved in liquid nitrogen using the programmed freezer with home cryoconservator "Gekmolit". All patients are discharged. One patient with myelogenetic disease died in 70 days after transplantation and disease relapse. The state of the other 7 patients is satisfactory in 927 months.

At the IBR-2 pulsed reactor in Dubna a new neutron Fourier diffractometer FSD is under construction. FSD continues the development of neutron Fourier diffractometry at long-pulse neutron sources, which was started several years ago with the high-resolution Fourier diffractometer HRFD at the IBR-2. Whereas HRFD is mainly used for precise structural refinement, FSD is optimised for internal stress measurements in bulk materials. The FSD design satisfies the requirements of high luminosity, high resolution, a specific sample environment, a wide range of dhkl, and fixed scattering angles 2θ=±90°. It consists of a mirror neutron guide, a fast Fourier chopper for the neutron-beam intensity modulation, a ±90° MultiCon ZnS(Ag) 6Li-loaded detector system with both geometrical and electronic focusing, a five-axis goniometer ‘Huber’ and loading machines, and VME-based RTOF analysers for data acquisition. Examples of the first experimental results obtained with FSD are presented.