The aim of this work was to obtain simulated flow patterns of rough surfaces by aerodynamic flow at different speeds for comparison with the results obtained by anemometry from images of particles in ...a laboratory wind tunnel. The results obtained by the program Comsol Multiphysics, which is used to simulate complex high-turbulent flows characteristic of gas flows in aircraft engines and gas turbine plants.
Abstract
The aim of the work is to determine the effect of a rough surface on the airflow flowing around it, depending on the degree of roughness of this surface. Experimental visualization of the ...flow of air around samples with various rough surfaces is carried out. The experimental results are compared with the theoretical results obtained as a result of modeling this process based on the RANS system of equations.
Thermodynamic properties of 2-methylfuran Yu. Ilin, D.; Tarazanov, S.V.; Druzhinina, A.I. ...
The Journal of chemical thermodynamics,
July 2021, 2021-07-00, Letnik:
158
Journal Article
Recenzirano
•The commercial sample of2-Methylfurane was purified.•Heat capacities, parameters of fusion and purity were measured.•The smoothedthermodynamics functionsin region from 10 to 350 K were ...calculated.•The thermodynamics functions of formation at 298.15 K were obtained.
The heat capacity of 2-methylfuranin the temperature range of 8–350 K was determined by vacuum adiabatic calorimetry. The temperature, the enthalpy and the entropy of fusion and purity of investigated sample were determinedbyfractional melting. Thesmoothed thermodynamic functions (changes in enthalpy,entropyand Gibbs energy) in the region of 8–350 K were calculated. The entropies of formation and Gibbs energiesof formationof2-methylfuranat 298.15 K inthe liquid and ideal gas states werefound, using the literature data.
The study used a large sample of elementary schoolchildren in Russia (N = 3,448, 51.6% were girls, with a mean age of 8.70 years, ranging 6–11 years) to investigate the congruency, format and ...heterogeneity effects in a nonsymbolic comparison test and between-individual differences in these effects with generalized linear mixed effects models (GLMMs). The participants were asked to compare two arrays of figures of different colours in spatially separated or spatially intermixed formats. In addition, the figures could be similar or different for the two arrays. The results revealed that congruency (difference between congruent and incongruent items), format (difference between mixed and separated formats) and heterogeneity (difference between homogeneous and heterogeneous conditions) interacted. The heterogeneity effect was higher in the separated format, while the format effect was higher for the homogeneous condition. The separated format produced a greater congruency effect than the mixed format. In addition, the congruency effect was lower in the heterogeneous condition than in the homogeneous condition. Analysis of between-individual differences revealed that there was significant between-individual variance in the format and congruency effects. Analysis of between-grade differences revealed that accuracy improved from grade 1 to grade 4 only for congruent trials in separated formats. Consequently, the congruency effect increased in separated/homogeneous and separated/heterogeneous conditions. In general, the study demonstrated that the test format and heterogeneity affected accuracy and that this effect varied for congruent and incongruent items.
Abstract
We demonstrate that in ferromagnets with the D
3h
point group of symmetry a possible origin of phase transition from a collinear ferromagnetic state to a non-collinear state can be the ...fourth order contributions to the free energy density that are allowed by this point group of symmetry. At the same time, Dzyaloshinskii-Moria interaction vanishes in such materials. Via symmetry analysis we derive seven possible fourth order contributions to the free energy density with respect to the unit vector of the local magnetization direction but only two of them can be considered as independent. Moreover, for two-dimensional systems only one survives. Considered symmetry class is essential because a large group of two-dimensional intrinsic ferromagnets belongs to it, for example a monolayer Fe
3
GeTe
2
. The four-spin chiral exchange does also manifest itself in peculiar magnon spectra and favors spin waves.
For the first time nanostructures of anodized aluminum oxide (AAO) were synthesized using hydrofluoric acid based electrolytes under potentiostatic mode with varied oxidation conditions. As-grown ...oxide layers were amorphous and had sponge-like disordered structure with ramified pores system of 50 to 300 nm diameters. All samples under daylight demonstrated blue emission with power up to 10 μW that was seen by naked eye. It was shown that integral intensity of photoluminescence (PL) emission band in 350 - 650 range increases up to 7 - 60 times depending on synthesis details. Observed PL spectra were approximated by superposition of two components with Emax = 2.74 and 2.44 eV, FWHM = 0.63 and 0.53 eV. It was substantiated that studied emission have intrinsic origin and can be attributed to F22+ - and F2-centers.
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