No. 8 (2019)

The paper discusses the features of the use of acoustic transmitting parametric array for acoustic sensing of the vertical temperature distribution in the atmosphere. Known acoustic loca-tors used for these purposes have different directional characteristics at different frequencies. Parametric transmitting array due to the peculiarities of virtual array formation retain the same directivity characteristic at all frequencies of waves generated in the medium. However, the inho-mogeneity of the pump wave interaction medium affects the amplitude of the generated waves. Theaim of the work is to assess the influence of changes in the propagation velocity of acoustic waves at different ambient temperatures on the parameters of the waves formed as a result of interaction. The problem of determining the influence of sound velocity changes on the characteristics of a parametric array based on the solution of the Khokhlov-Zabolotskaya-Kuznetsov equation for inhomogeneous medium is posed. As inhomogeneities, the change in the velocity of acoustic waves propagation in a medium with temperature varying along the path of pump waves interaction is chosen. To solve this problem, the article considers the possible methods of acoustic determination of the vertical temperature distribution in the atmosphere, assesses the advantages and disad-vantages of existing methods and concludes that it is possible to use a radiating acoustic paramet-ric antenna to determine the vertical temperature distribution in the atmosphere. To determine the effect of change of speed of wave propagation on parametric antenna characteristics based on modified equations of Khokhlov-Zabolotskaya-Kuznetsov for heterogeneous environments pro-vides a solution that explicitly indicated the change in the propagation velocity along the wave propagation path is explicitly indicated. Estimates of the change are given and a conclusion is made about the insignificant influence on the amplitude of the generated signal.

Currently, the state of Affairs for fishing for biological resources of the world's oceans is changing dramatically. Work related to environmental monitoring of marine areas is carried out at the Federal, regional, territorial and local levels. The main purpose of monitoring the state of water bodies is to provide competent authorities and nature users with information about the quantitative and species composition of living organisms, as well as information support for deci-sion-making procedures in the field of environmental protection and environmental safety. Sys-tematic generalization of information about the world's oceans, biological phenomena in the body of knowledge, is necessary for understanding the distribution, abundance and availability of fish. In order not to undermine the biological stocks of hydrobionts of the world's oceans, it is neces-sary to regularly conduct monitoring and research work on the quantitative accounting of biologi-cal resources, regulate quotas for fish and shellfish. Due to the complexity of accounting for bio-logical resources in shallow areas of The world ocean using existing instruments, issues related to the development and research of a traverse survey sonar for monitoring marine hydrobionts in shallow water are considered, since this topic is relevant, and the issue of preserving the biologi-cal diversity of reservoirs has become acute. The technology of traverse survey using sonar is characterized by a high degree of automation, information content, efficiency of research and low labor costs compared to traditional methods based on the use of trawls, dragging. It should also be noted that due to the use of this method, there is no injury to the inhabitants of reservoirs, since often injured hydrobionts die. In the traverse view sonar, a "non-petal " narrow- directional direc-tional pattern is formed in the parametric mode in the vertical plane, which allows increasing the range of action to 700 meters or more. And in the horizontal plane, to increase echo contact and search performance, a wide directional pattern (30–40 deg) is formed by using several pumping antennas installed at a certain angle relative to each other. The development and further applica-tion of the above-mentioned hydroacoustic device will allow creating a kind of database with in-formation about the territorial distribution of fish accumulations in shallow water areas. However, for the practical implementation and creation of such complex technical devices, a whole range of applied research and development work is required. The grandiosity of all that is connected with the human idea of the ocean, served as the basis for a widespread opinion about the unlimited and inexhaustible resources of the world's oceans. However, this opinion is not valid for biological resources. This is evidenced by signs of depletion of fish stocks and other fisheries in irrationally fished areas of the ocean.

The relevance of environmental monitoring of water bodies is given in the work. The productivity of various regions of the oceans is described. The creation of a complex of environ-mental monitoring of the water area is proposed. The structure of the ecological monitoring sys-tem for water bodies is presented. It consists of a wide-range side-scan sonar, a parametric profilograph, a side-scan parametric sonar and a parametric monitoring system for shallow water bodies on long tracks. A description is given of broadband side-scan sonars, a parametric profilograph, a parametric cross-section sonar and a powerful high-directional broadband radiat-ing parametric system of a stationary type. The directional diagrams of the broadband side-scan sonar in two mutually perpendicular (vertical and horizontal) planes over the entire range of operating frequencies (77, 100, 127 and 155 kHz) are presented. An echogram of a survey of a port facility is provided. For a parametric profilograph, options are presented for the design of pump antennas (outboard version (with a cowl) and version for uninhabited vehicles), radiation patterns at the pump frequency (150 kHz) and at difference frequencies (10, 15, and 20 kHz), as well as a shallow-water profilogram pond. For a broadband parametric traverse survey sonar, the ad-vantages of the device are presented and a 3D model is presented. The description of powerful high-directional broadband radiating parametric systems of a stationary type presents the pro-spects for their application and describes the experiment in the Black and Azov Seas. Stationary type parametric systems can be an effective tool for studying compression of acoustic signals in marine waveguides, implementing virtual acoustic barriers, building underwater navigation sys-tems and controlling the movement of underwater vehicles and systems, creating highly efficient marine sounding systems for environmental purposes to detect submerged objects and inhomogeneities.

It is known that ultrasonic methods of visualization of internal structures of biological ob-jects are safer in comparison with x-ray and magnetic resonance imaging and are characterized by fewer restrictions for conducting research. However, a significant disadvantage of such meth-ods is not high enough resolution. This is because most existing ultrasound diagnostic systems are based on the laws of linear acoustics. One of the promising areas of research is the development of methods for visualizing the internal structures of biological objects and determining the size and boundaries of inhomogeneities based on the nonlinear interaction of the acoustic field withbiological tissues. In this paper, we consider a method for improving the accuracy of the process of localization of heterogeneity in a biological object. To solve this problem, we use a replacement method based on calculating the ratio of the distribution of the pressure amplitude of the second-ary field of an acoustic wave that passed through a biological object that has pathological inclu-sions to the pressure of the secondary field of a wave that passed through a homogeneous medium with known nonlinear characteristics. The article presents an expression describing the distribu-tion of the acoustic pressure of the field of secondary sources, on the basis of which the calcula-tions were performed. For mathematical modeling, a model of a biological object consisting of muscle tissue and pathological inclusions (fibroids) was used. In the framework of this study, the ratio of the secondary field pressure change for this model and a homogeneous reference medium with known characteristics is calculated. The obtained data is presented in the form of contour graphs that reflect the location of the inhomogeneity. The results of the calculations showed a greater efficiency of using the substitution method for the process of determining the location of inhomogeneous inclusions in the bioobject model compared to visualization methods based on restoring the pressure distribution of the secondary acoustic field. It is shown that the use of the substitution method makes it possible to more accurately determine the boundaries of inhomogeneities. Therefore, the substitution method can be used to obtain projection data and restore the distribution of an acoustic nonlinear parameter in a flat section of a biological object.

The paper considers the choice of optimal acoustic wave parameters for ultrasonic im-aging based on nonlinear effects of its interaction with biological tissues. The changes of the second harmonic pressure at different values of the frequency and pressure of the first har-monic are calculated. As a model, the medium consisting of the following biological tissues was considered: adipose tissue, muscle tissue, whole liver, blood, pathological tissue (fi-broids). For adipose and muscle tissues, the calculation of the change in the acoustic wave rupture distance at different parameters of the probing pulse of the main frequency was car-ried out. The calculation of the distance of the gap was conducted in order to determine the most optimal ratio of the initial characteristics of the ultrasonic wave and a second harmonic of an acoustic signal, allowing you to visualize the distribution of the acoustic nonlinearity parameter.

Maintaining a vertical posture, posture and coordination are the most important neurophysio-logical functions, the violation of which can indicate both neurological problems in the body and various injuries of the musculoskeletal system. Postural stability is the ability to keep the body in balance. Postural oscillation is defined as the constant deflection and correction of the center of gravity position as a result of the high center of gravity and low support of the base in the orthostatic position, which leads the body to unstable equilibrium. Together with the somatosensory and vestibu-lar systems, the visual system processes information about the relative position of body segments and the magnitude of the forces acting on the body needed to maintain balance. Without adequate inter-action between these systems, the body cannot acquire the ability to properly explore and interactwith the environment. It is shown that the position of the center of pressure, in some cases coinciding with the center of mass of the test object, plays an important role in the mechanisms of postural regu-lation. Possibility of application of technologies of stabilometry in sports of the highest achievements is investigated. The effectiveness of stabilometry methods in post-traumatic rehabilitation and adap-tation of athletes is noted. Studies were conducted on a group of children involved in the sports sec-tion of Taekwondo by the method of "Tolerance control" before and after training. The basic indica-tor in the technique is the indicator "quality of the balance function", which allows you to quickly assess the condition of the athlete. Based on the processing of experimental data, the dynamics of the quality of the equilibrium function is obtained and analyzed, on the basis of which it is possible to conclude about the objectivity of the equilibrium assessment and the high efficiency of this method applicable to the sport of higher achievements.

Objective: to analyze electroencephalographic parameters in patients with hypertension and cognitive complaints receiving standard antihypertensive therapy, without concomitant cardiovas-cular disease, for the purpose of early diagnosis of brain damage as the main target organ in hy-pertension. Materials and methods: 135 people were examined (95 people with arterial hyperten-sion and 43 potentially healthy). The average age of patients is 63±8.2 years. As a result of the diagnosis, patients were distributed as follows: no cognitive impairment-82 people (60.7 %), mild cognitive impairment – 32 people (23.7 %), moderate cognitive impairment – 21 people (15.6 %). The studies were carried out on the apparatus "Encephalan-EEGR-19/26". Results: after the treatment, the majority of patients had a reduction of pre-reported complaints, an increase on the "Montreal scale" from 1 to 2 points, a decrease in anxiety and depression on the "Hospital scale", an increase in indices on SF-36. According to EEG data, there was an increase in the frequency of the main alpha rhythm and the total bioelectric power of the rhythm, the appearance of a pro-nounced spectral peak in the alpha range, a decrease in the power of the slow-wave rhythm in the anterior parts, which also indicates a positive dynamics that correlates with clinical data and test data. Conclusions: the study established the diagnostic value of quantitative processing of elec-troencephalogram (the frequency of the main rhythm, the power of the theta and Delta rhythms in the anterior parts, the total power of the b. e. a.), which suggest the need for additional therapy to standard antihypertensive treatment.

The article discusses the issues of assessing and monitoring the level of functioning of the motor control system of highly qualified athletes. The purpose of the article is to test the hypothe-sis about the influence of various factors on the body control system during the performance of movements of the follower type by athletes within the framework of the concept of internal models. A biomechanical complex with biological feedback Stabilan-02 (OKB "Rhythm", Taganrog) was used as an instrumental testing technique. A special testing program, as well as a developed algo-rithm for processing experimental data, made it possible to collect a significant database of the country's leading athletes over 10 years of observation. In this experiment, more than 100 athletes in biathlon and alpine skiing took part. The experimental data presented in the article show the influence of the selected factor of sports specialization on the change in indicators characterizing the level of coordination abilities of highly qualified athletes. The influence of the training process associated with the specifics of the main competitive exercise is shown. The results of the study showed that the developed methodology for evaluating and calculating data associated with sen-sorimotor corrections allows using it in the practice of the training process to monitor the state of the athletes' motion control system. Testing results by the proposed methodology allow to increase the efficiency of the training process management and significantly deepen the understanding of processes directly related to the technical training of athletes of various sports specialization and qualifications.

Electrical impedance tomography is a promising method of medical imaging that allows re-constructing the conduction field inside the object (or changing it) based on electrical measurements on the surface of a conductive object. To do this, a low-frequency high-frequency electric current of small amplitude is passed through the object under study and potentials on the surface of the object under study are simultaneously recorded. The sensitivity of the method is determined by the sensitivi-ty of the measuring channel of the device for collecting and transmitting data for electrical imped-ance tomography. The paper presents a study of the sensitivity of the measuring channel of a data acquisition and transmission device for electrical impedance tomography. The work presents a de-vice for collecting and transmitting data for electrical impedance tomography, built on the basis of the input / output board L-CARD E502, as well as the measuring channel of this device. The measur-ing channel consists of a pair of measuring multiplexers, a programmable differential amplifier and an analog-to-digital converter. The effect of the multiplexer resistance on the result of measuring potential differences is estimated. The theoretical sensitivity limit of the device is estimated based on the bit depth of the analog-to-digital converter and the maximum gain of the programmable differen-tial amplifier. The theoretical limit of sensitivity of the measuring channel as part of a data acquisi-tion and transmission device for electrical impedance tomography was 1.22 mOhm. The reasons for the impossibility of reaching the theoretical limit of sensitivity are described using the test load as an example. As a test load, a ring of resistors is considered, as well as a ring of resistors with an addi-tional node in the center connecting nodes on the periphery through the resistor. Based on the circuit simulation of the test load in the MicroCAP circuit simulation environment, an estimate of the real sensitivity limit of the device, which amounted to 35 mOhm, is given. In the course of the experiment, a change was made in the resistor in the potential registration region, followed by an assessment of the voltage change in the potential registration region. Increasing the sensitivity is possible in two ways: by increasing the bit depth of the analog-to-digital converter or by increasing the gain of the measuring channel by introducing additional amplification stages.

The first Einthoven record on an electrocardiogram (ECG), which was launched in 1904.The paper deals with the problem of developing a generator of reference signals of electro-cardiography based on STM32 microcontrollers. The objectives of the study is to prepare a math-ematical description of the signals based on the Matlab package for the subsequent sending ofthese signals to the microcontroller Board. A hardware solution is proposed to create a program-mable multichannel electrocardiograph signal generator using only a programmable logic matrix based on STM32 microcontrollers and a small number of passive external components. A mathe-matical model of generating an artificial electrocardiogram and its application in a programma-ble simulator of signals of complex shape. When constructing medical decision support systems, computer tools are often used to provide not only the registration of biological signals, but also a quantitative assessment of certain parameters of these signals. For example, modern digital elec-trocardiographs allow you to automatically measure the amplitude-time characteristics of individ-ual elements of the electrocardiogram (ECG), which carry diagnostic information about the pro-cesses of excitation and relaxation of areas of the heart muscle. The use of an ECG generator has several advantages: reducing test time, simplifying the use of ECG signals without the need for expensive methods.