Abscissa Axis Research Articles

Shear wave velocity-based evaluation of cyclic mobility type of liquefaction and validation by centrifuge model tests in LEAP

Existing study shows that small-strain shear modulus is a promising parameter for characterizing soil liquefaction resistance, while liquefaction resistance is liquefaction type dependent. In this study, firstly a revisit of laboratory tests on saturated sands was conducted to explore the relationship between liquefaction resistance CRR and small-strain shear modulus Gmax with emphasis on cyclic mobility type of liquefaction. The investigation indicates that in the stress-normalized space of cyclic resistance and small-strain shear modulus, the fitting curve of soil testing data does not always approach to the coordinate origin and there will be an intercept on the abscissa axis. Based on this finding, a more general form of the power function between liquefaction resistance and small-strain shear modulus is proposed. Then, undrained cyclic triaxial tests were conducted in conjunction with the data available from LEAP to establish the power function between CRR and Gmax for medium dense to dense Ottawa F-65 sand, which leads to an updated characterization model on the basis of Zhou-Chen model. Finally, centrifuge model tests of submerged gently sloping ground of Ottawa F-65 sand conducted at Zhejiang University (i.e., ZJU) for LEAP were used to compile liquefaction and non-liquefaction case histories with shear wave velocity measurement to investigate the validity of the updated model for evaluating the cyclic mobility type of liquefaction. The test results show that the updated model could classify the case history datasets produced by centrifuge model tests well. And the further consideration of initial shear stress acting on the slope could enhance the evaluation performance of this characterization model, which is worth of further research.

Method for stabilizing the detection efficiency of grazing angle incidence boron-lined neutron detectors

Boron-lined gaseous neutron detectors intrinsically suffer from the “self-absorption” effect and hence their neutron detection efficiencies might be nonconstant, when the threshold of them undergoes unexpected variation. To address this problem, we propose a maximum likelihood estimation-based threshold determining method, via which the pulse height spectra acquired under different high voltages could be rescaled to the same abscissa axis of deposited energies. Monte Carlo simulations were conducted to study the relationship between the precision of the threshold determination and the counting statistics, as well as the energy deposition spectrum, indicating that the grazing angle incidence neutron detector can achieve a fairly small relative standard variation for a spectrum with a modest total neutron counts. A prototype grazing angle incidence neutron detector has been constructed and tested under high voltages ranging from 500 V to 950 V. The experimental results show that, with the maximum likelihood estimation-based method, the threshold's relative standard deviations are less than 10% even with a total neutron counts as low as 100. As a result, the maximum relative variance of the counting plateau curve is 4.8% in the region of [500 V, 900 V] when the detector operates at a grazing angle of 1.8°. The results presented in this study indicate that combining the grazing angle incidence and the maximum likelihood estimation-based threshold determining method would be a promising way to achieve stable neutron detection efficiency for neutron detectors with the boron layer as the neutron convertor.

Determining the parameters of the functioning for a nonlinear ballistic system in a real external environment

Determining the parameters of the functioning for a nonlinear ballistic system in a real external environment

Визначення коефіцієнтов гідродинамічної моделі кавітуючих насосів рідин-них ракетних двигунів за їх теоретичними передатними матрицями

The characterization of cavitating pumps of liquid-propellant rocket engines (LPRE) is an important problem because of the need to provide the pogo stability of liquid-propellant launch vehicles and the stability of liquid-propellant propulsion systems for cavitation oscillations. The development of a reliable mathematical model of LPRE cavitating pumps allows this problem to be resolved. The goal of this work is to determine the cavitation number and operating parameter dependences of the coefficients of a lumped-parameter hydrodynamic model of LPRE cavitating pumps from their theoretical transfer matrices obtained by a distributed-parameter model. The following coefficients are found as a function of operating parameters: the cavitation elasticity, the cavitation resistance, the cavity-caused disturbance transfer delay time, and the cavitation resistance distribution coefficient. The last two coefficients are new in the hydrodynamic model of cavitating pumps, and they were introduced when verifying the model using experimental and theoretical pump transfer matrices. Analyzing the cavitation resistance distribution coefficient as a function of operating parameters shows that it markedly decreases with increasing cavitation number. This testifies to that the location of the lumped cavity compliance is shifted from the mid position towards the pump inlet. Therefore, the assumption that the lumped cavity compliance is located in the middle of the attached cavity regardless of the cavitation number is not justified. The fact that the distribution coefficient as a function of cavitation number intersects the abscissa axis near a cavitation number of 0.25 may indicate the boundary of existence of attached cavities and thus the applicability boundary of the theoretical model. The disturbance transfer delay time as a function of cavitation number sharply increases at cavitation numbers of about 0.05. At cavitation numbers of about 0.25, it is close to a constant.

Измерение транспортабельности и стандартного геометрического отклонения транспортабельности радиоактивных аэрозолей с помощью каскадного импактора

An approach is proposed for the operational measurement of transportability and standard geometric deviation of transportability of radioactive aerosols in industrial conditions. The cascade impactor is preliminarily calibrated (graduated) in transportability units - this is a preliminary single measurement of transportability at each impactor cascade. After calibrating the impactor in transportability units, the transportability and standard geometric deviation of the transportability of radioactive aerosols can be repeatedly measured periodically and/or as needed. To do this, it is enough to measure the activity of the radionuclide at each impactor cascade using any available method. Based on measurements of radionuclide activity at each impactor cascade,an integral transportability distribution function is constructed for all cascades in percentage, then on paper. for lognormal probability graphs, the logarithms of the transportability of the cascade elements are plotted along the ordinate axis (but transportability values are indicated), and the total amount of the fraction activity is plotted along the abscissa axis. The obtained points determine the straight line f(S), the required transportability is S50, where f(S50) = 50%, the desired standard geometric deviation is bg = S84/S50, where f(S84) = 84%. A patent for the invention RU 2801822 C2 was issued for the presented means of measuring transportability and standard geometric deviation of transportability of radioactive aerosols.

RESULTS OF LABORATORY STUDIES OF THE EXPANDATE FORMATION PROCESS

The expanded preparation of feeds is carried out using high-temperature (80–140 °C) expanders. These expanders perform the task of preparing food products and feeds under high pressure (1–10 MPa). The expansion process is accompanied by chemical changes such as denaturation of proteins, amino acids, vitamins, starch, and enzymes. Additionally, there is a transformation of the physical and mechanical properties of the feed components, converting them into expandates. The laboratory research aims to establish the regularities of the compression pressure changes with the deformation of feed components and the density of the obtained expandates under various technological parameters. The study explores the impact of the granulometric composition of the feed, its moisture, and temperature on the deformation diagram, representing the relationship between stress and material deformation. For this purpose, testing was conducted using the Heckert FP-100/1 testing machine and additional devices and equipment. As research factors, the feed's moisture W (10 %, 20 %, 30 %), temperature T (80 °C, 110 °C, 140 °C), and the average particle diameter of ground feed components Dμ (0.5 mm, 1.5 mm, 2.5 mm) were selected. The study was conducted using a full-factor experiment, comprising a total of 27 experiments with three repetitions. For each experiment, a relationship of compression pressure changes with deformation (elastic hysteresis) of the feed components ΔP(εz) was obtained. The research criteria include: the area SΔP enclosed inside the elastic hysteresis loop ΔP(εz); the coefficient of mechanical losses (or relative hysteresis) Ψ, calculated as the ratio of the hysteresis loop area SΔP to the area enclosed between the stress-strain curve and the abscissa axis, where deformations SP1 are plotted; the height of the obtained expandate sample ha; and the density of the obtained expandates ρa. As a result of the laboratory research on the expandation process, dependencies of the compression pressure changes with the deformation of feed components ΔP(εz) were established. Additionally, correlations of the area of the elastic hysteresis loop SΔP, the coefficient of mechanical losses Ψ, the height of the obtained expandate sample ha, and the density of the obtained expandates ρa with the feed's moisture W, temperature T, and the average particle diameter of ground components Dμ were determined. By solving the compromise task of minimizing the coefficient of mechanical losses Ψ and maximizing the density of the obtained expandates ρa, the following rational technological parameters were obtained, ensuring the most effective feed expansion process: Dμ = 0.5 mm, T = 119.2 °C, W = 19.1%, ρa = 292.9 kg/m3.

Processing algorithm of weekly records of the Roztochia landscape-geophysical station thermograph М-16АН as a response source of air temperature data

Formulation of the problem. During the database processing of the Roztochia landscape-geophysical station (RLGS), located in the village of Bryukhovychi, Lviv, an air temperature data gap for 1990–1991 was found. The task of the research was to find those sources about air temperature at RLGS, which would allow us to fill in the gaps during the night hours when, unfortunately, observers did not make measurements. Problems of further research. In comparison with the method adopted in Ukraine for processing weekly thermograph tapes, in this study, it is proposed to correct the air temperature value during their processing, compensating for accelerated or slowed rotation of the weekly thermograph drum. It is suggested to use only those dry bulb measurements carried out on days with cloudy or rainy weather. The purpose. The main goal was to find an algorithm for processing weekly thermograph tapes under the conditions of a partial absence of temperature measurements using a dry thermometer by an observer to fill in the gaps regarding night air temperature data. Research methods. The air temperature values falling during the measurement period were read from the thermograph tapes, and an electronic table was formed. The temperature values (difference estimation) were compared with the corresponding ones recorded in the "Books" of KM-1. At the same time, it was necessary to make two new corrections. The first correction will be made along the ordinate axis, changing the value of the temperature recorded by the thermograph compared to the values of the temperature measured by the dry thermometer. The second correction was made along the abscissa axis, compensating for the drum's slowed down or accelerated rotation. Presentation of the main research material. A brief description of the proposed algorithm for thermograph tape processing is as follows. In the spreadsheet, in separate columns, we record the temperature values during the observation periods: a) by dry thermometer and b) by thermograph at the points corresponding to the observation periods. Subtracting columns (a) and (b) values, we determine those dry bulb temperature values suitable for calculating corrections. We reject too significant differences that occur during rapid temperature changes. Next, we look for points on the thermograph tape that serve as time benchmarks (the starting and ending points of the temperature curve and the places where the observer draws vertical lines). These temperature values will form column (c). It will additionally include the temperature values obtained by reading the temperature from the tape for rainy and/or overcast days for points whose localization is corrected for time. The difference between column (a) and column (c) will give the temperature correction for several observation periods on each weekly strip taken separately. The last step is the linear interpolation of temperature corrections between neighbouring points of intermediate observation periods. Practical value. The proposed algorithm may help eliminate gaps in temperature data at other observation points, where the thermograph served as a backup device for recording air temperature. Research results. The measurements that fall on rainy and overcast weather are best suited for calculating thermograph corrections when air temperature changes slow down. It is necessary to identify benchmark points of time fixation, to which the observer must add the moments of putting on and removing the tape from the drum.

EFFICIENCY OF THE FINANCIAL MANAGEMENT OF THE MODERN ORGANIZATION

The relevance of the issue of the prospects for the development of financial management is due to the need for financial entities to look for ways to increase the level of forecasting stability in their activity in the conditions of instability in the temporary economic situation.In particular, it includes the implementation of both capital structure financing decisions and decisions on: profit growth policies; tactical financing policy such as initial public offering, financial restructuring and debt financing; short-term financial management, such as cash, inventory and receivables and others.In this regard, the main theoretical concepts for the formation of the financial policy of financial entities have been identified, by considering a certain temporary economic situation - after the Covid crisis and the subsequent inflation.The financial expression of the effectiveness of the applied financial management in the specified situation was examined.This implies determining the main categories of quality activity of financial structures.For this purpose, the definitions of the effectiveness and efficiency of financial management have been derived and adapted. The main differences in the two meaningful concepts, evaluating the activity of financial institutions, through a system of criteria and indicators, are specified.In addition, a research model is presented - a regression analysis of the inflation of the Republic of Bulgaria with a duration of 18 months and a regression equation is derived.A forecast of the inflationary trends of a type common to the country's economic entity with a duration of 6 months was carried out.On this basis, a method for determining the inflation coefficient has been derived, using a first-order equation and the slope, the tangent of the angle made with the abscissa axis and a certain point from the estimated inflation graphic part. With the help of financial mathematics, a practical example of applying strategies of financial entities to determine the effectiveness and mainly the efficiency in reaching the desired state of the said entity was solved.Conclusions and recommendations are made for reactions of a type of financial entity to reduce the negative consequences of sudden changes and sharp fluctuations of the business environment in the current temporary financial situation.

НЕЧЁТКАЯ ИДЕНТИФИКАЦИЯ ПАРАМЕТРОВ ЭПИДЕМИОЛОГИЧЕСКОЙ МОДЕЛИ С ТРЕМЯ КОГОРТАМИ

Target. Obtain an analytical form of an approximate solution for a system of firstorder nonlinear differential equations that describes the dynamics of the epidemic in the SIR model of three cohorts: healthy – infected – immune. Methodology. The solution for cohort S is sought in the form of a logistic curve in the form of a normal distribution function Ф. By eliminating the dependence of S(t) on the recovery rate γ it was possible to construct a dependence for I(t) as an integral of the shape of S(t). Results. Quantitative examples demonstrate that with an increase in the infection rate β, the mode of the form I(t) shifts to the left along the abscissa axis, and the maximum value in this mode increases according to the trend. The system maintains parametric stability for values of 0.15 ≤ β ≤ 0.4. Conclusion. The solution for the SIR model can be generalized to a model with a larger number of cohorts.

Filtration velocity under roller squeezing

Analytical dependencies are determined that describe the patterns of change in filtration rates in the squeezing area. It was established that the fluid filtration rate along the abscissa axis at the boundaries of the compression zone is zero, and inside the zone, it takes negative values. It was found that the fluid filtration rates along the ordinate axis are zero at the beginning of the compression zone; they increase to a maximum at a point lying on the line of centers, and in the zone of strain restoration, they depend on the angle that determines the position of the point where the fluid changes direction.

ON ONE PROBLEM OF INTEGRAL GEOMETRY

The paper is devoted to a problem of integral geometry on a two-dimensional plane. In the band of the two-dimensional space , a two-parameter family of curves is given. Each of these curves consists of two arcs , which are adjacent to each other at the vertex of the curve at an angle , and the other ends rest on the axis. With respect to the branches of the curve , certain smoothness conditions are assumed. The family of curves can be parametrized using the coordinates of the vertices of the curves, that is, each curve from this family can be put in an unambiguous correspondence with the coordinates of its vertex. For each point , there is only one curve belonging to the specified family and having the point as its vertex. It is required to determine the function from the following equation for a given function where – region bounded curves and the axis . The theorem (uniqueness of the solution) is proved. If , then the solution of equation (*) is unique in the class of continuous finite functions with a carrier in . In proving the theorem, the invariance of the family of curves L(ξ,n) and weight functions to shifts along the abscissa axis is significantly used. Further, using the Fourier transform from the function with respect to the variable and the permissible transformations, a family of Volterra integral equations of the second kind is obtained with respect to the Fourier image from the function with respect to the first variable. The paper also provides an estimate of the conditional stability of the considered integral geometry problem

IN MECHANICS OF DEFORMABLE SOLIDS PRIMARY PLASTIC ON PANEL DURING POWER UP DEVELOPMENT OF DEFORMATIONS

One of the most important issues in solid mechanics is the development and application of optimal methods for estimating the resistance of dispersion materials. Currently, the theory of propagation of cracks in solid bodies is widespread due to the wide use of high-strength materials and large-sized structures and devices in various fields of technology. The article discusses the methods of studying the problems of the interaction of two factors - strengthening the panel with stiffening ribs made of unidirectional composite material and weakening it with a number of circular holes and cracks protruding from its contour. An infinite isotropic elastic riveted panel weakened by a periodic system of circular holes and two cracks along the abscissa axis segments near each hole is considered. The contours of the holes and the edges of the cracks are free from external forces. Transverse stiffness ribs made of metal composite material are riveted to the plate. In the calculation scheme, the effect of riveted reinforcing ribs is replaced by the concentrated forces applied at the points of location of the rivets. The values of the concentrated forces are found depending on the geometrical and physical parameters of the problem. Stress intensity factors and ultimate loadings were calculated depending on the geometrical and physical parameters of the problem. It has been shown that there is a stable phase of crack development under certain specified conditions. The development of initial plastic deformations (embryonic cracks) emerging from the contour of circular holes in a plate reinforced with stiffness ribs is studied. The material of the plate is elastic-perfect-plastic satisfying the Tresca-Saint-Venant condition. It is assumed that the plastic deformations are concentrated along some slip lines emanating from the contour of the hole. By satisfying the boundary conditions, the solution of the problem leads to a singular integral equation. Then the singular equation of the problem is brought to a system of algebraic equations without the intermediate step of bringing it to the Fredholm equation. The resulting system was solved by the Gaussian method with the selection of principal elements for different values of n (n is the number of Chebyshev nodes in the division of the interval). The values of concentrated forces are found depending on the geometrical and physical parameters of the problem. The dependences of the length of the plasticity bands on the applied load, the geometrical parameters of the problem and the yield point of the material were found. Using the local dissipation condition (KPT-criteria), a ratio was obtained to determine the destructive edge loading.

MATHEMATICAL MODEL FOR DECISION MAKING SYSTEM BASED ON THREE-SEGMENTED LINEAR REGRESSION

Context. The problem of approximation of empirical data in the decision-making system in safety management.. The object of the study was to verify the adequate coefficients of the mathematical model for data approximation using information technology.
 Objective. The goal of the work is the creation adequate math-ematical model using information technology on the bases analyze different approaches for approximating empirical data an that can be used to predict the current state of the operator in the flight safety system..
 Method. A comparative analysis of the description of the transformation of information indicators with a non-standard structure. The following models of transformation of information indicators with similar visual representation are selected for comparison: parabolas of the second and third order, single regression and regression with jumps. It is proposed to use new approaches for approximation, based on the use of the criterion proposed by Kuzmin and the Heaviside function. The adequacy of the approximation was checked using these criteria, which allowed to choose an adequate mathematical model to describe the transformation of information indicators. The stages of obtaining a mathematical model were as follows: determining the minimum sum of squares of deviations for all information indicators simultaneously; use of the Heaviside function; optimization of the abscissa axis in certain areas; use of the linearity test. The obtained mathematical model adequately describes the process of transformation of information indicators, which will allow the process of forecasting changes in medical and biological indicators of operators in the performance of professional duties in aviation, as one of the methods of determining the human factor in a proactive approach in flight safety.
 Results. The results of the study can be used during the construction of mathematical models to describe empirical data of this kind.
 Conclusions. Experimental studies have suggested recommending the use of three-segment linear regression with jumps as an adequate mathematical model that can be used to formalize the description of empirical data with non-standard structure and can be used in practice to build models for predicting operator dysfunction as one of the causes of adverse events in aviation.
 Prospects for further research may be the creation of a multiparameter mathematical model that will predict the violation of the functional state of the operator by informative parameters, as well as experimental study of proposed mathematical approaches for a wide range of practical problems of different nature and dimension.

Волны деформации в двух соосных, физически нелинейных оболочках с конструкционным демпфированием, взаимодействующих с окружающей средой и заполненных жидкостью

The paper investigates longitudinal strain waves in physically nonlinear coaxial elastic shells containing a viscous incompressible fluid situated both between the shells and within the inner shell. The study takes into account the effects that the following factors have upon the magnitude and velocity of the wave: viscosity, fluid motion inertia, the medium surrounding the outer shell, and structural damping in the shell material. As it is impossible to evaluate the strain wave models proposed via qualitative analysis methods, using numerical methods is necessary. We numerically investigated the model presented using a specific difference scheme to represent its equations, one similar to the Crank --- Nicolson scheme for the thermal conductivity equation. We show that the velocities and amplitudes of strain waves in the shells do not change when disregarding the following factors: the fluid inside the shell, structural damping in the shell material, and the influence of the surrounding elastic medium. The waves evolve in the positive direction of the abscissa axis. At the same time, taking nonlinearity into account leads to increased wave velocity as compared to the linear case, when the wave propagation velocity equals the speed of sound, which means the waves become supersonic. We performed a numerical study of this case and obtained results matching the exact solution. If we take into account the effect that the fluid motion inertia within the inner shell has upon the wave velocity, then a decrease in the strain wave velocity is observed. Taking into account the presence of an elastic medium surrounding the outer shell leads to an increase in velocity. Considering the viscous properties of the fluid within the inner shell and the damping properties of the shell material results in decreased strain wave magnitudes. The models proposed can form the basis for designing modern non-destructive testing devices

Projectile flight parameters measurement method based on the spatial distribution of light-screen thickness

The light-screen is widely used as a sensor in the measurement of projectile flight parameters of rapid-fire weapons due to the high sensitivity and the fast response. The current measurement theory regards the light-screen as an ideal plane. therefore, it is necessary to arrange at least four light-screens in space to form a detection array to measure the flight velocity and coordinates of the projectile. However, the actual light-screen is not an ideal plane but has a certain thickness, and the spatial shape distribution of light-screen thickness should follow a certain law. Based on the formation principle of light-screen, the spatial shape distribution of light-screen thickness is analyzed in this paper. According to the corresponding relationship between the trajectory position and the thickness distribution of the light-screen the characteristic difference of the LSPTS (Light-screen Passing Through Signal) is studied, then the measurement model is built and the measurement formula is deduced. Finally, the live firing experiment is carried out, and the results show that the proposed measurement method can realize the simultaneous measurement of the flight velocity and impact coordinates with only two light-screens, which reduces the number of light-screens by half compared with the current measurement methods. And the experiment result shows that the relative error of the impact coordinate measurement results is 8.1% on the abscissa axis and 8.2% on the ordinate axis, and the relative error of flight velocity measurement error is 3.1%. The research in this paper can provide a new idea for measuring the flight parameters of projectile by photoelectric principle.

Взаємодія плоских пружних хвиль. Врахування квадратичної та кубічної нелінійності

The interaction of elastic plane harmonic waves in the material, the nonlinear properties of which are described by the elastic potential of Murnaghan, is investigated theoretically. The displacement vector is depended of only one spatial variable and time, a record of the complete system of equations for plane waves moves along the abscissa axis is recorded and used. The interaction of longitudinal waves with a separate considering cubic nonlinearity is investigated. On the basis of the cubic equation of motion, the interaction of four harmonic waves is studied. The method of slowly variable amplitudes is used. Firstly the two-wave interaction is investigated, then the interaction of four waves is described. Shorten and evolutionary equations are obtained, the first integrals of these equations and the record of the law of conservation for a set of four interacting waves are obtained. An analogy is made between the triplets studied when taking into account the interaction of three waves and the triplets investigated in the case under consideration, taking into account the four-wave interaction, quadruplets.

Properties for the spectral parameters of intermolecular vibrations obtained using Raman scattering of light in dilute aqueous solutions of hydrogen peroxide and in the water

The spectra of Raman scattering (in the region 4-350 cm-1) of dilute aqueous solutions of hydrogen peroxide in a wide range of concentrations (from 3 to 0.024%), were measured. The spectral parameters of the high-frequency band of intermolecular (longitudinal) vibrations, obtained using the previously proposed approximating function, were analyzed. To do this, the spectral parameters of the band (for each experiment) were plotted on a diagram in which the abscissa axis is the square of the band width, and the ordinate axis is the square of the band frequency. Previously, it was shown that in such coordinates the water points are located in two regions separated by an inclined strip, in which spectral points (frequency gap) are practically absent. For points of hydrogen peroxide solutions with a concentration from 3 to 0.33%, all points are grouped near the straight line approximating them and are located below this frequency gap. For a series with extended range of peroxide concentrations from 3 to 0.024%, the scatter of points from the approximating straight line increases, but also most of the points are located below the gap. Of the rest of points, several points are near the edge of the gap, some of them are inside the gap, but the gap remains. It has been suggested that the presence of this gap is due to the fact that in the liquid phase some of the water molecules are bound to four neighbors, while the remaining molecules are bound to a smaller number of neighbors. Keywords: Raman scattering, hydrogen peroxide, water, intermolecular vibrations, high-frequency band, inhomogeneous distribution, frequency gap, destruction of high-frequency states.

Ferroelectric hysteresis and magnetoelectric effect in orthorhombic Dy-=SUB=-1-x-=/SUB=-Ho-=SUB=-x-=/SUB=-MnO-=SUB=-3-=/SUB=- single crystals

In Dy1-xHoxMnO3 single crystals with the orthorhombic space group Pbnm, ferroelectric hysteresis loops were measured for compositions with x=0 and 0.3. As the content of Ho3+ ions increases, the hysteresis loop narrows and for x=0.3 it no longer manifests itself. An analysis of the signal corresponding to the hysteretic behavior of a ferroelectric showed that even harmonics can be obtained only if the hysteresis loop is not symmetric about the abscissa axis. In view of the latter, the hypothesis that the second harmonic of the magnetoelectric effect is a consequence of the complex dependence of the polarization on time due to its hysteresis becomes doubtful. Measurements of the dependence of the inverse magnetoelectric effect on the amplitude of the applied electric field Delta M(E) showed that the first harmonic remains linear with respect to the electric field even in the electric field strength region where the domain structure of the ferroelectric is rearranged. Keywords: multiferroics, ferroelectricity, hysteresis.

Сегнетоэлектрический гистерезис и магнитоэлектрический эффект в орторомбических монокристаллах Dy-=SUB=-1-x-=/SUB=-Ho-=SUB=-x-=/SUB=-MnO-=SUB=-3-=/SUB=-

In Dy1-xHoxMnO3 single crystals with the orthorhombic space group Pbnm, ferroelectric hysteresis loops were measured for compositions with x=0 and 0.3. As the content of Ho3+ ions increases, the hysteresis loop narrows and for x=0.3 it no longer manifests itself. An analysis of the signal corresponding to the hysteretic behavior of a ferroelectric showed that even harmonics can be obtained only if the hysteresis loop is not symmetric about the abscissa axis. In view of the latter, the hypothesis that the second harmonic of the magnetoelectric effect is a consequence of the complex dependence of the polarization on time due to its hysteresis becomes doubtful. Measurements of the dependence of the inverse magnetoelectric effect on the amplitude of the applied electric field ΔM(E) showed that the first harmonic remains linear with respect to the electric field even in the electric field strength region where the domain structure of the ferroelectric is rearranged.

ПРОГРАММНЫЕ И АППАРАТНЫЕ СРЕДСТВА ДЛЯ ОПРЕДЕЛЕНИЯ ТЯГОВОГО СОПРОТИВЛЕНИЯ РАБОЧИХ ОРГАНОВ МАШИН ДЛЯ ОСНОВНОЙ ОБРАБОТКИ ПОЧВЫ

The efficiency of the use of agricultural machinery depends on various factors, one of which is the rational acquisition of machines with energy resources based on the calculation of traction resistance. The purpose of the study is to describe an experimental setup for measuring, accumulating and analyzing data on the traction resistance of working bodies of machines for basic tillage and the results of research based on it. The main method of research is conducting an experiment using software and hardware; methods of mathematical statistics were also used. The authors consider the features of the software and hardware used to measure the traction resistance of working bodies for basic tillage. The hardware of the experimental installation consists of a personal computer, an acid GP-1223 battery, a 3.5 mm Jack microcontroller power cable, a panel, an RS-485 – USB-B Aries AC4 interface converter, a microcontroller, a 15-pin COM port, Type DEE 500 kg load cells. The software allows you to get interactive graphs of the traction resistance of the working body, change settings, in particular, scaling, the limits of measurement of the ordinate scale, the displacement of the abscissa axis. Studies of tag resistance are given on the example of the paws of a cultivator for stubble after buckwheat (at a processing depth of 14, 18 cm, an operating speed of 5, 10, 15 km/h), and an experimental setup is proposed. Cultivator racks were used for experiments: vertical rigid and spring-loaded with replaceable paws and tips. The measurement results confirm that an increase in the speed of movement significantly affects the growth of the traction resistance of the studied working organ for cultivation.