Modelling of the evolution of a droplet cloud in a turbulent flow

The effects of droplet inertia and turbulent mixing on the droplet number density distribution in a turbulent flow field are studied. A formulation of the turbulent convective diffusion equation for the droplet number density, based on the modified Fully Lagrangian Approach, is proposed. The Fully Lagrangian Approach for the dispersed phase is extended to account for the Hessian of transformation from Eulerian to Lagrangian variables. Droplets with moderate inertia are assumed to be transported and dispersed by large scale structures of a filtered field in the Large Eddy Simulation (LES) framework. Turbulent fluctuations, not visible in the filtered solution for the droplet velocity field, induce an additional diffusion mass flux and hence additional dispersion of the droplets. The Lagrangian formulation of the transport equation for the droplet number density and the modified Fully Lagrangian Approach (FLA) make it possible to resolve the flow regions with intersecting droplet trajectories in the filtered flow field. Thus, we can cope successfully with the problems of multivalued filtered droplet velocity regions and caustic formation. The spatial derivatives for the droplet number density are calculated by projecting the FLA solution on the Eulerian mesh, resulting in a hybrid Lagrangian–Eulerian approach to the problem. The main approximations for the method are supported by the calculation of droplet mixing in an unsteady one-dimensional flow field formed by large-scale oscillations with an imposed small-scale modulation. The results of the calculations for droplet mixing in decaying homogeneous and isotropic turbulence are validated by the results of Direct Numerical Simulations (DNS) for several values of the Stokes number

Highly non-linear resonance fluctuations of gas in a closed pipe

Highly non-linear oscillations of gas in a closed pipe were researched experimentally. Dependencies of the pressure oscillation amplitude were obtained for various frequencies and amplitudes of the gas excitation near the first eigenfrequencies when transiting to the shock-wave oscillation mode

Some Remarks on Combining Forms in English-Japanese Dictionaries

© 2016, Pleiades Publishing, Inc.Previously unknown isononylcalix[8]arene was synthesized from commercially available isononylphenol. The properties of the product (solubility, extraction ability, tendency to aggregation) were compared with those of the known tert-butylcalix[8]arene. The extraction of 137Cs, 99mTc, and 241Am from alkaline carbonate solutions with solutions of p-alkylcalix[8]arenes (alkyl = tert-butyl, isononyl) in tetrachloroethylene was studied. The dependence of the distribution ratios on pH of the aqueous phase in the interval from 11 to 13.9 and on the nature of functional groups in the calixarene core was determined. The composition of extractable solvates of cesium and americium with calix[8]arenes was found. Calix[8]arenes extract cesium from alkaline solutions more efficiently than p-tert-butylphenol, their nonmacrocyclic analog, does. tert-Butylcalix[8]arene exhibits the highest performance, which may be due to formation of aggregates 5.7 ± 0.8 nm in diameter in the organic phase at pH 13.5 of the aqueous phase. The isononyl derivative exists in the monomeric form (particle diameter 1.9 ± 0.5 nm)

4.各部門の活動内容 臨床工学科

Highly non-linear oscillations of gas in a closed pipe were researched experimentally. Dependencies of the pressure oscillation amplitude were obtained for various frequencies and amplitudes of the gas excitation near the first eigenfrequencies when transiting to the shock-wave oscillation mode

Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal

A methodology is worked out to retrieve the numerical values of all the main parameters of the six-dimensional adiabatic potential energy surface (APES) of a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from ultrasound experiments. The method is based on a verified assumption that ultrasound attenuation and speed encounter anomalies when the direction of propa- gation and polarization of its wave of strain coincides with the characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr crystal, employed as a basic example, we observed anomaly peaks in the temperature dependence of attenuation of ultrasound at frequencies of 50-160 MHz in the temperature interval of 40-60 K for the wave propagating along the [110] direction, for both the longitudinal and shear modes, the latter with two polarizations along the [001] and [110] axes, respectively. We show that these anomalies are due to the ultrasound relaxation by the system of non-interacting Cr2+ JT centers with orthorhombic local distortions. The interpretation of the ex- perimental findings is based on the T2g (eg +t2g) JTE problem including the linear and quadratic terms of vibronic interactions in the Hamiltonian and the same-symmetry modes reduced to one interaction mode. Combining the experimental results with a theoretical analysis we show that on the complicated six-dimensional APES of this system with three tetragonal, four trigonal, and six orthorhombic extrema points, the latter are global minima, while the former are saddle points, and we estimate numerically all the main parameters of this surface, including the linear and quadratic vibronic coupling constants, the primary force constants, the coordinates of all the extrema points and their energies, the energy barrier between the orthorhombic minima, and the tunneling splitting of the ground vibrational states.Comment: 8 pages, 3 figure

Selecting and structuring teaching content algorithm for physical and mathematical disciplines, aimed at students’ project-technical competence formation

© 2015, Review of European Studies. All right reserved. The most important component of the professional competence of an engineer is the synthesis of project and technical competences—project-technical competence, suggesting a set of special knowledge, skills and proficiencies, personal qualities necessary for the effective specialists’ performance of their professional duties, in particular, for the successful implementation of engineering projects requiring technical calculations running, capabilities to effectively operate in real life, to get oriented in production situations, to adapt to changing conditions, to work in different teams. In this connection, the problem of selecting and structuring teaching content of physical and mathematical disciplines, aimed at the formation of project-technical competence of technical university students, is becoming relevant. The paper presents an algorithm for selecting and structuring the physical and mathematical disciplines teaching content, aimed at the formation of students’ project-technical competence, involving a sequence of analytical and preparatory, organizational-substantive, procedural-methodological, as well as correction-implemental stages. The article submissions are of practical value to Mathematics and Physics teachers for selecting and structuring the content of these disciplines

CsMgPO4

Caesium magnesium orthophosphate is built up from MgO4 and PO4 tetra­hedra (both with . m. symmetry) linked together by corners, forming a three-dimensional framework. The Cs atoms have .m. site symmetry and are located in hexa­gonal channels running along the a- and b-axis directions

Assessment of internal pressure effect, causing additional bending of the pipeline

Article justifies accounting for internal pressure effect in the pipeline, causing additional bending of the pipeline. According to some scientists, there is an erroneously used concept of the equivalent longitudinal axial force (ELAF) Sx, which depends on working pressure, temperature stresses, and joint deformations of pipelines with various types of soils. However, authors of the article use ELAF Sx concept at construction of mathematical model of stress-strain state (SSS) for complex section of the trunk pipeline, and also reveal it when analyzing the results of calculating the durability and stability of the pipeline. Analysis of SSS for calculated section of the pipeline was carried out for two statements of the problem for different values of operation parameters. In the first statement, effect of internal pressure causing bending of the pipeline is taken into account, and in the second it is neglected. It is shown that due to effect of ELAF Sx at p0 = 9.0 MPa, Dt = 29 °C extreme value of bend increases by 54 %, extreme values of bending stresses from span bending moment increase by 74 %, and extreme value of bending stresses from support bending moment double with regard to corresponding SSS characteristics of the pipeline. In case of neglecting the internal pressure effect causing additional bending of the pipeline (second statement of the problem), error in calculating the extreme value of bend is 35 %, extreme value of bending stresses from span bending moments is 44 %, and extreme value of bending stresses from support bending moments is 95 %

Magnetic Resonance Investigations of h-YbMnO<inf>3</inf>

© 2016, Springer-Verlag Wien.Polycrystalline samples of ytterbium manganites have been synthesized with deficiency of Yb3+ ions. The X-ray analysis showed that the structure of the sample is hexagonal (h-YbMnO3) with the space group P63cm. The analysis of the X-ray diffraction peak intensities allowed to find the occupancy of Yb3+ and Mn3+ positions which are about 89 and 100 %, respectively. The electron spin resonance (ESR) measurements were performed using X (9.4 GHz), Q (34.2 GHz) and W (94.1 GHz) bands. The ESR spectrum displays the broad exchange-narrowed Mn3+ resonance line and an additional signal, which is attributed to the ferromagnetically correlated clusters, formed by mixed-valence manganese ions near vacant Yb3+ positions, confirmed by the observation of the hysteresis loop in the magnetization of h-YbMnO3