Comparison of various spectral control schemes using displacers
Comparison of various spectral control schemes using displacers
R. A. Vnukov, A. A. Vorontsova
In this paper, one of the possible approaches to compensate for excessive reactivity at the beginning of the campaign is considered – spectral regulation. Its implementation is based on the use of displacement rods that change the water-fuel ratio during the fuel campaign. To assess the effect on the neutron-physical characteristics that arise in the assembly when displacers are introduced into its design, various models are proposed that differ in the placement of rods in the fuel assembly. The comparison takes place with the original version of the fuel assembly, which has a similar geometry to the VVER-1200 fuel assembly. Based on a single scheme for regulating the water-fuel ratio, the contribution to the extension of the fuel campaign for models with displacers is estimated. The comparison is carried out with the initial fuel assemblies, where the fuel campaign is 49 MW * day/kg for model 1 and 78 MW * day/ kg for model 2. The results showed the fundamental possibility of extending the fuel campaign due to the phased extraction of displacer rods, which tighten the spectrum. In a model with displacers in the intertwined space, the campaign extension was 8 MW*day/kg, which is equivalent to 16%; in the model where the displacers are placed in the guide channels, the extension was 6 MW* day/kg, which is equivalent to 5%. Complete replacement of boric acid in the versions under consideration turned out to be impossible, while the required concentration of H3BO3 in the coolant to compensate for excessive reactivity at the beginning of the campaign increased due to a decrease in boron efficiency with a more rigid neutron spectrum in the models. Keywords: spectral regulation, fuel assemblies, boric acid, fuel campaign, light-water reactor.
Show AbstractInteraction of Radial Velocity Flow and Magnetic Flux in Emerging Active Regions of the Sun
Interaction of Radial Velocity Flow and Magnetic Flux in Emerging Active Regions of the Sun
A. M. Sadykov$^{1,2}$, S. A. Krasotkin$^{1,2}$
In this article, the authors investigate the physical processes involved in the formation of active regions (AR). Specifically, the magnetic flux emergence (magnetic tube) hypothesis is tested based on direct observations of the magnetic field and Doppler shifts obtained from the Global Oscillation Network Group (GONG) ground-based telescope network. The study encompasses the analysis of 24 emerging ARs observed during the period from 2011 to 2022. A strong correlation between magnetic flux and the downward radial velocity flow was found. The results indicate that the magnetic flux emergence hypothesis cannot fully explain the evolution of ARs during the early stages of their development.
Show AbstractThe influence of cholesterol and calcium ions on the interaction of cryoprotectors with a biological membrane model
The influence of cholesterol and calcium ions on the interaction of cryoprotectors with a biological membrane model
V. Yu. Svechnikova$^{1,2}$, O. V. Mishukova$^{1,3}$, A. G. Mironova$^4$, G. B. Khomutov$^2$, M. A. Marchenkova$^1$, S. A. Yakovenko$^{2,5}$
In this work, we studied the effects of three cryoprotectors – ethylene glycol, dimethyl sulfoxide, sucrose – on the compression isotherms of egg yolk Langmuir monolayers both in the presence and in the absence of cholesterol in the monolayer. The influence of calcium ions from the subphase affecting the effectiveness of cryoprotection on π-A-isotherms is also examined. In addition, the elastic properties of the obtained monolayers are investigated by calculation and comparison the compression modulus of the monolayer. The scientific novelty of the work is in consideration of a complex biosimilar system (an egg yolk monolayer, cholesterol and their mixtures) on the surface of the aqueous solution of the nutrient mixture and obtaining information about the specific interaction of different cryoprotectors with lipid membranes. We found that when calcium ions and cryoprotectors are simultaneously added to the subphase, they block each other's influence on the lipid monolayer and reduce the effectiveness of cryoprotection. Cholesterol in the yolk in a ratio of 1:50 m/m changes the properties of the monolayer, which leads to increased action of cryoprotectors. Also, for the first time, the effect of a significant increase in surface pressure (by∼20 mN/m)was detected when cryoprotectors were added to the system under consideration. This effect can serve as an indicator of the effectiveness of membrane dehydration by cryoprotectors and can be used to find the most effective and safe cryoprotector compositions. Since the study of the mechanisms of calcium interaction (the most important signaling cation)with biological membrane and membrane-like systems is important for understanding the various effects caused by medicinal and biologically active drugs at the cellular level, the study is of interest for various fields of biophysics and biomedicine.
Show AbstractAcoustic emission during the “crystal-liquid” phase transition in a honeycomb structure of the “honeycomb” type
Acoustic emission during the “crystal-liquid” phase transition in a honeycomb structure of the “honeycomb” type
E. M. Aseev
A complex system is being studied experimentally, which is a honeycomb structure, normal-conjugated with the compositional structure, and containing within itself a defect of the “water condensate” type in the form of ice crystals. To detect such a defect, the phenomenon of acoustic emission is used. Usually, to produce acoustic emission, mechanical impact on the object is used. But, unlike this traditional loading (compression or tension) of a sample by external forces, this uses a variation in the temperature field in which the sample is placed. During the heating of the experimental sample, the ice-water phase transition begins, leading to the phenomenon of acoustic emission. The dependences of the amplitudes of acoustic signals on time and on the rate of temperature change reveal a clear difference between samples with the “water accumulation” defect and samples without such defects.
Show AbstractInvestigation of the operation of a fiber-optic communication line at extremely low temperature conditions.
Investigation of the operation of a fiber-optic communication line at extremely low temperature conditions.
V. G. Nesterov, V. V. Davydov
The necessity of additional research of mechanical and optical characteristics, assessment of operability and degradation of special optical fibers with a core doped with GeO2 in extremely low temperature operation is justified. The application of a model for the destruction of optical fibers is considered, which makes it possible to evaluate the mechanical properties of quartz fibers with a core of pure quartz and doped with germanium oxide. An experimental setup has been developed and research has been conducted. It has been found that with an increase in the degree of doping of the optical fiber core with germanium oxide, the limit of the increase in optical losses at low temperatures shifts towards zero. This creates restrictions on the use of doped core fibers when operating on highways. The obtained data allow the developers of fiber-optic communication lines, taking into account climatic conditions, to develop an optimal design of the main communication line, taking into account the MSVD and VAD manufacturing of optical fibers.
Show AbstractExpress method of kidney monitoring for early detection of kidney damage
Express method of kidney monitoring for early detection of kidney damage
D. V. Vakorina$^1$, G. V. Stepanenkov$^1$, V. V. Davydov$^1$, D. V. Davydova$^{1,2}$
The necessity of determining kidney damage at an early stage using fast and reliable express methods was substantiated. A method based on refractive index measurements at three wavelengths with refractive index grading to the values of three main parameters (osmolarity, number of solids, density) was proposed for express method of kidney damage control. Additionally, the sizes of protein compounds were investigated and their sizes were also graded to refractive indices. The results of the study of model solutions are presented. Theoretical indices of kidney condition determination are established. The peculiarities of biological environment control using small-size refractometers working on the effect of total internal reflection are considered. Current express methods of kidney disease diagnostics by means of urine measurement are analyzed. The advantages of using the refractometer design at three wavelengths in comparison with other methods are noted. The peculiarities of measuring the refractive index of biological liquids on the example of urine are established. The results of investigation of various samples at temperature T = 20°C in dependence of refractive index on wavelengths and their analysis are presented. The comparison of the obtained results with the results of measurements in clinical diagnostics is carried out.
Show AbstractA 100 MHZ signal conversion device with low phase noise
A 100 MHZ signal conversion device with low phase noise
A. A. Popov$^1$, V. V. Davydov$^1$, D. D. Savin$^1$, V. V. Naumova$^2$
The main disadvantages of high-stability UHF generators and difficulties of using such equipment on satellites and other mobile objects are revealed. A device for converting a highly stable signal into several coherent ones is proposed. The choice of low-noise operational amplifiers (OA) as an element base for the converter is proved. Theoretical study of noise coefficients and phase noise power spectrum densities of imported and domestic low-noise operational amplifiers is done with the use of MATLAB environment. The circuit diagram of the device based on selected models of OA, which was later modified by increasing the number of output signals is designed. The necessity to revise the general structure of the circuit considering on the parasitic capacitances of the OA is declared. Its adequacy was checked with using the program package NI Multisim. The printed circuit board for direct laboratory studies of the phase noise power spectrum density of device is built. Keywords: phase noise, signal converter, UHF, hydrogen standard, low noise amplifier, current noise, voltage noise.
Show AbstractOn unidirectional propagation of Pocchammer-Chree waves in cylindrical auxetic
On unidirectional propagation of Pocchammer-Chree waves in cylindrical auxetic
D. V. Ampilogov
The problem of propagation of Pocchammer-Chree waves in cylindrical auxetic is discussed in this work. The approximated evolution equation and general solution for left and right waves displacement field are built by means of projection operators method in particular case of axial symmetric material for exponential inition conditions.
Show AbstractSimulation of diffraction patterns on poly- and single crystals in the special courses and cours of laboratory work and of the Department of Solid State Physics, Faculty of Physics, Moscow State University
Simulation of diffraction patterns on poly- and single crystals in the special courses and cours of laboratory work and of the Department of Solid State Physics, Faculty of Physics, Moscow State University
A. G. Khundjua$^1$, E. A. Brovkina$^1$, M. M. Melnikov$^2$
The complex of modeling diffraction patterns developed at the Department of Solid State Physics of the Faculty of Physics of Lomonosov Moscow State University is considered. The complex includes several sections: 1) diffraction on polycrystals - tasks for the construction and analysis of diffraction pattern on polycrystalline samples; 2) diffraction on single crystals - modeling and analysis of electron diffraction and Laue patterns; 3) modeling of point patterns of diffraction on two-phase crystalline objects related by orientation ratio (including martensitic transformations). Various options for using computer programs for a course of laboratory work and special courses of the department are discussed.
Show AbstractOn the set of locally equilibrium configurations of the potential energy of a multiatomic cluster
On the set of locally equilibrium configurations of the potential energy of a multiatomic cluster
K. E. Plokhotnikov
The paper studies the question of the set (uniqueness) of locally equilibrium configurations of the potential energy of a multiatomic cluster. A molecular system consisting of many, generally speaking, different atoms is called a multiatomic cluster. A formalism is proposed for constructing the entire line of multiparticle potentials to describe an arbitrary molecular system. The concepts of “shape matrix” or “morph” for each of the multiparticle potentials are intro-duced and discussed. The algorithm for constructing the potential energy function of a multia-tomic cluster is determined so that one could talk about building a well-defined configuration of cluster atoms as the only possible one. This algorithm is considered as a way to solve the problem of choosing the configuration of cluster atoms as locally equilibrium. The sets of locally equilibrium configurations of binary and multiparticle potentials are studied in detail. A set of locally equilibrium configurations of a linear combination of binary and multiparticle potentials is also considered. It is shown that in the latter case, the set of locally equilibrium configurations is determined mainly by the binary potential. The general constructions and conclusions are illustrated by examples of reproduction as locally equilibrium standard configurations of water, methane, ethylene and benzene molecules. Suitable potentials are constructed having the specified configurations as global minima. Using examples of the description of clusters of water, benzene and carbon, the question of the causes of the appearance of a variety of locally equilibrium con-figurations is investigated. An algorithm for constructing a complex, composite shape matrix for clusters consisting of many identical molecules is discussed. The use of the concept of “shape matrix” allows us to naturally take into account all possible integral subunits in the molecular system, as well as describe the limits within which these wholes are reproduced unchanged.
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