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The need for developing metrological support for the measurement of gas components in metals and alloys and trace impurities in various industrial products (metallurgy, medicine, etc.) is analyzed. The authors examine the needs of industries for the development of more sensitive measurement methods and procedures, as well as an expanded nomenclature of reference materials having a lower error (uncertainty) of the certified characteristic than the certified characteristic error of currently existing type-approved composition reference materials. Reference materials developed for use in state regulation should be traceable to the primary standards of mass (molar) fraction and mass (molar) concentration: GET 196-2023 State Primary Standard for the units of the mass (molar) fraction and mass (molar) concentration of components in liquid and solid substances and materials based on spectral methods; GET 176-2019 State Primary Standard for the units of mass (molar, atomic) fraction and mass (molar) concentration of components in liquid and solid substances and materials based on coulometry; GET 217-2018 State Primary Standard for the units of mass fraction and mass (molar) concentration of inorganic components in aqueous solutions based on gravimetric and spectral methods; GET 208-2019 State Primary Standard for the units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry. The need for and ways of developing and creating a metrological support system for Raman spectrometry in the Russian Federation are analyzed, including to confirm the traceability of units for quantitative Raman analysis. To address these issues, GET 196-2023 includes sulfur, carbon, and hydrogen analyzers; an inductively coupled plasma mass spectrometer; and a Raman system. The composition and metrological characteristics of GET 196-2023 are presented. In addition, a draft state hierarchy scheme for instruments measuring mass (molar) fraction and mass (molar) concentration, as well as fluorescence, of components in liquid and solid substances and materials based on spectral methods has been developed and presented. The draft state verification scheme establishes the procedure and methods for transferring the units of the mass (molar) fraction (in absolute units) and mass (molar) concentration of components (grams per cubic decimeter; mole per cubic decimeter) from GET 196-2023 to measuring instruments with indication of measurement error and uncertainty. Also, secondary and working standards are used to transfer relative fluorescence units to measuring instruments. [ABSTRACT FROM AUTHOR]

The effect of oil contamination on growth of mono- and dicotyledonous plants (clover and ryegrass), on the one hand, and the effect of plants on oil biodegradation in soil, on the other hand, were studied in a long-term field experiment. It was found that plants respond differently to oil contamination of soddy-podzolic soil. Clover was more resistant to oil than ryegrass. Biosynthesis of photosynthetic pigments (chlorophylls and carotenoids) was not disturbed in clover, and the plant yield was fully restored by the end of the third growing season. The content of oxidative enzymes in clover leaves was 2–10 times higher than in ryegrass. Biological activity of soil planted with clover was 1.5–2 times higher correlating with the biochemical parameters of plants. Higher basal respiration in soil planted with clover corresponded to the enhanced oil biodegradation. The differences in the carbon of oil products between soils planted with clover and ryegrass appeared at the end of the third growing season at high doses of oil (5 and 10 L m−2). [ABSTRACT FROM AUTHOR]

An overview of Russian and foreign reference materials of fluorescent properties is presented along with a discussion of the possibility of their use in metrology. A principle of sensitivity analysis for fluorescent instruments based on scaled relative fluorescence units is discussed. Technical and metrological characteristics of a fluorescence gauges kit based on organic dyes with various concentrations developed and certified at the All-Russian Research Institute for Optical and Physical Measurements are given. [ABSTRACT FROM AUTHOR]

In this article, we study a one-dimensional degenerate fourth-order parabolic equation (a thin-film model) with a source term. We prove existence of generalized weak solutions for the case n > 0 and study interface propagation properties like: finite speed propagation and waiting time phenomenon for the case 1 < n < 2 . Our analysis is based on applications of global and local energy-entropy a priori estimates. Also, we illustrate some of our main analytical results by numerical simulations. [ABSTRACT FROM AUTHOR]

The results of development of fluorescence calibration standards based on phosphate matrix glass activated with ions of rare-earth metals are presented. The calibration standards are designed for spectral correction of emission spectra and systemic monitoring of sensitivity fluctuations in spectrofluorimeters. The possibility of using them for the calibration of Raman spectrometers is considered. [ABSTRACT FROM AUTHOR]

The phase complex of the quinary reciprocal system Li+,Na+,K+||F–,Cl–,Br– was studied for the first time. Partition according to graph theory determined that the tree of phases of the system has linear structure and comprises stable polytopes: the pentatope LiF–NaF–KF–KBr–KCl, the hexatope LiF–NaBr–NaCl–KCl–KBr–NaF, and the heptatope NaCl–KCl–KBr–LiBr–LiCl–LiF–NaBr, connected by the stable tetrahedron LiF–NaF–KCl–KBr and the stable pentatope LiF–KBr–NaBr–NaCl–KCl. Phase equilibria in the stable tetrahedron LiF–NaF–KCl–KBr were studied by differential thermal analysis and confirmed by X-ray powder diffraction analysis. In the tetrahedron, there is monovariant phase equilibrium L ⇄ LiF + α + KClxBr1 – x, where α is a limited solid solution based on NaF (LiF–NaF system), and KClxBr1 – x is a continuous series of solid solutions based on KCl and KBr. A 3D computer model of the projection of the phase complex on the concentration tetrahedron was constructed using the KOMPAS 3D software. The crystallization volumes of equilibrium phases are determined. [ABSTRACT FROM AUTHOR]

The effect of the endocrine disruptor nonylphenol on the biological activity of loamy soddy-podzolic soil (Eutric Albic Retisol (Abruptic, Loamic, Aric, Ochric)) was studied in model experiments. The upper horizons of loamy soddy-podzolic soil sampled in Leningrad oblast were the object of this study. The number of soil microorganisms, the activity of soil enzymes, and soil respiration were determined with the methods commonly used in soil microbiology and biochemistry. The content of nonylphenol in soil samples was determined using high-performance liquid chromatography. Soil contamination with nonylphenol was shown to cause time- and dose-dependent changes in the activity of the pool of nitrogen, carbohydrates, and redox enzymes and increases the basal respiration. The results obtained are an important stage necessary for risk assessment of soil contamination with alkylphenols, and can be used in the development of a remediation methodology for soils contaminated with endocrine disruptors. [ABSTRACT FROM AUTHOR]

We derive a new model for the coating flow inside the alveolar compartment, taking into account pulmonary surfactant production and recycling by Type 2 cells as well as its degradation. As the thickness of alveolar coating is much smaller than the average radius of the alveoli, we employ the classical lubrication approximation to describe the thin liquid film dynamics in the presence of pulmonary surfactant, which is a surface tension-reducing agent and thus prevents the lungs from collapse. In the lubrication limit, we derive a degenerate system of two coupled parabolic partial differential equations that describe the time evolution of the thickness of the coating film inside the alveoli together with that of the surfactant concentration at the interface. We present numerical simulations using parameter values consistent with experimental measurements. With Marangoni effects being significant, it is found that any initial non-uniformity in surfactant concentration leads to a very fast redistribution of surfactant and accompanying change in film thickness, followed by a much slower relaxation of the film thickness to equilibrium during which surfactant concentration remains relatively uniform. [ABSTRACT FROM AUTHOR]

We examine the dynamics of a thin viscous liquid film on the outer surface of a solid sphere rotating around its vertical axis in the presence of gravity. An asymptotic model describing the evolution of the film thickness is derived in the rotating frame based on the lubrication approximation. The model includes the centrifugal and gravity forces and the stabilizing effect of surface tension. Depending on the values of the parameters, the problem admits different types of steady states: one with a uniformly positive film thickness, or those with one or two dry zones on the sphere. We prove that all steady states are energy minimizers and hence global attractors for axisymmetric states. [ABSTRACT FROM AUTHOR]

The influence of the prolonged application of different lime doses (including elevated ones) on the complex of soil microorganisms and the humus status of a sandy loamy soddy-podzolic soil was studied in a long-term field experiment. The content of labile humus substances extracted with 0.1 M KCl (pH 4.3-4.4) and that of organic matter extracted with hot water became reduced. When liming, the number of all the bacterial groups significantly increased. On the contrary, the number of micromycetes decreased by 3.5-4.2 times. However, the liming did not cause any changes in the complex of soil microorganisms and the content of organic matter, thus indicating the normal functioning of the whole soil ecosystem. [ABSTRACT FROM AUTHOR]

Quaternary reciprocal systems of alkali metal fluorides, chlorides, and bromides were partitioned into simplexes by a geometric method and a graph method. Phase transformations and chemical reactions in the bordering ternary reciprocal systems were described. Conversion lines were experimentally studied, and information on crystallizing phases within the composition prisms of the M,M|F,Cl,Br systems (M and M are group 1 s-block elements) was obtained. [ABSTRACT FROM AUTHOR]

A quaternary mutual system of fluorides, chlorides, and bromides of lithium and cesium was partitioned into simplexes by a geometric method and by a graph method. Phase transformations and chemical reactions in the bordering ternary mutual systems were described. A conversion line was experimentally studied, and information on crystallizing phases within the composition prism of the Li,Cs|F,Cl,Br system was obtained and confirmed by X-ray powder diffraction data. The characteristics of the minimum in the LiF-CsF-CsCl-CsBr tetrahedron were determined. [ABSTRACT FROM AUTHOR]

We study the dynamics of thin liquid films on the surface of a rotating horizontal cylinder in the presence of gravity in the small surface tension limit. Using dynamical system methods, we show that the continuum of shock solutions increasing across the jump point persists in the small surface tension limit, whereas the continuum of shock solutions decreasing across the jump point terminates in the limit. Using delicate numerical computations, we show that the number of steady states with equal mass increases as the surface tension parameter goes to zero. This corresponds to an increase in the number of loops on the mass-flux bifurcation diagram. If n is the number of loops in the mass-flux diagram with 2n + 1 solution branches, we show that n + 1 solution branches are stable with respect to small perturbations in the time evolution of the liquid film. [ABSTRACT FROM AUTHOR]

The results of a study of charge transfer luminescence (CTL) in a YAG:Yb monocrystal and trans-parent ceramics obtained by vacuum sintering and nanocrystalline (VSN) technology from a weakly agglomerated powder are presented. The kinetics of CTL decay at temperatures of 8, 100, and 300 K and different excitations were obtained. The results of the measurements are analyzed from the viewpoint of comparison of monocrystal and ceramics properties. The high quality of the latter is demonstrated. [ABSTRACT FROM AUTHOR]

quaternary reciprocal system of fluorides, chlorides, and bromides of lithium and potassium was partitioned into simplexes by a geometric method and by a graph method. Phase transformations and chemical reactions in the boundary ternary reciprocal systems were described. A conversion line was experimentally studied, and information on crystallizing phases within the composition prism of the Li,K|F,Cl,Br system was obtained and confirmed by X-ray powder diffraction data. An immiscibility region in the LiF-KCl-KBr stable triangle was outlined. [ABSTRACT FROM AUTHOR]

We present the results of studying the luminescence properties of transparent ceramics YAlO:Yb obtained by the vacuum sintering and nanocrystalline technology. In the course of research, we measured the luminescence and luminescence excitation spectra, as well as the temperature and kinetic behavior of luminescence. Our results are analyzed in comparison with the characteristics of corresponding single crystals. We revealed that processes of generation and relaxation of electronic excitations that occur in ceramics, in particular, in the charge transfer state, are similar to processes occurring in crystals. The behavior of two charge-transfer luminescence bands at 340 and 490 nm is studied. In the range 300-600 nm, we revealed a broad emission band of radiation of other type, which is also observed in spectra of undoped ceramics. This broad band is attributed to F centers. Emission and excitation spectra of charge transfer luminescence at a maximum of the temperature dependence of 100 K are measured for the first time. We found that, upon excitation in the charge transfer band, luminescence in ceramics is more intense than in single crystals with similar concentrations of Yb and has a higher quenching temperature. [ABSTRACT FROM AUTHOR]

Excellent properties of optical ceramics initially developed as laser materials make them attractive for scintillator applications. The effects of the porosity of ceramics on their luminescence properties is analyzed using a simplified model to account for scattering. The results of the study of optical and luminescence properties of a concentration series of YAG:Yb ceramics fabricated by vacuum sintering and nanocrystalline technology (VSN method) in a wide UV and VUV and X-rays excitation energy range are presented. The results are compared to those obtained for Yb-doped single crystals and undoped YAG ceramics and single crystals. [ABSTRACT FROM AUTHOR]

The main result of the present paper is the use of Pontryagin’s theorem for proving a criterion, based on the difference in the number of negative eigenvalues between two self-adjoint operators L− and L+, for the linear part of a Hamiltonian system to have eigenvalues with strictly positive real part (unstable eigenvalues). [ABSTRACT FROM AUTHOR]