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The paper considers tasks related to the search for the parameters of smart-systems with piezoelectric elements, to the electroded surfaces to which elements of electrical circuits are connected. The required parameters should provide the maximum damping properties of the simulated systems at free and steady-state forced vibrations. The paper presents the results of calculations of smart-system parameters providing maximum damping properties at free and forced vibrations, which were performed in the framework of continuum and discrete mechanics models. The results demonstrate variants for which the parameters found based on continuum mechanics models provide higher vibration damping rates. [ABSTRACT FROM AUTHOR]

The way biological systems respond to changes in parameter values caused by mutations is a key issue in evolution and quantitative genetics, as it affects fundamental aspects such as adaptation, selective neutrality, robustness, optimality, evolutionary equilibria, etc. We address this question using the enzyme–flux relationship in a metabolic network as a model of the genotype–phenotype relationship. The lack of a suitable mathematical tool from biochemical theory to investigate this relationship led us to use an analogy between electrical circuits and metabolic networks with uni–uni reactions. We show that a behaviour of diminishing returns, which is commonly observed at various phenotypic levels, is inevitable, irrespective of the complexity of the system. We also present a possible generalization to metabolic networks with both uni–uni and bi–bi reactions.

This work focuses on a dynamic electrical circuit whose dynamics are affine in the control input. Such dynamics are considered to be re-expressed in a canonical form, namely the port-Hamiltonian (pH) representation with dissipation, where the Hamiltonian is a quadratic function and has the unit of energy or power. On this basis, it allows revealing the transformation of energy (or power) inside the system, including the energy supply, storage and dissipation, thereby facilitating Lyapunov-based or energy-related control approaches for stabilization and optimization purposes. Two pH representations are proposed and compared; the first one is established with difficult-to-measure states while the second one is obtained with easier-to-measure states.

This work analyzes the electric impedance spectra of liver samples. Nyquist diagrams of experimental samples of different sizes were constructed. Optimal model equivalent electrical circuits of the systems studied were obtained and processed, and the parameters of their components were calculated. Changes in parameters and the tangent of the loss angle were shown. A conclusion was made about the interdependence of the electric field strength and the occurrence of stress, caused by using certain frequencies, on the size of the sample.

The article is dedicated to determining the energy indicators of a generating complex with stochastic wave energy gen-eration. The aim of the study is to compare the energy indicators and power consumption coefficient of wave energy generating complexes' simulation models with magneto-electric generators operating at variable speeds under resistive and resistive-capacitive loads with rectified voltage. The analytical method is employed to calculate the parameters and energy indicators of the magneto-electric generator. The calculation includes inductance, resistance, and voltage gen-erated by the rotor with permanent magnets in the three-phase winding of the magneto-electric generator for electrical circuit modeling with and without a three-phase current rectifier, as well as active-reactive and active loading. The rotor rotation frequency varies harmonically with the same period and amplitude for all electrical circuits. The deter-mined current in the electrical circuits is used to calculate the generator's electromagnetic field and energy indicators. Comparisons are made for circuits with active and active-reactive loads, including power consumption, power losses in the stator winding, power output from the generator, and the power consumption coefficient of wave energy. The com-parison of energy indicators is conducted under the condition of equal rotor oscillation frequency and shaft torque, achieved by varying the load resistance. Bibl. 10, fig. 8, table.

In this work, a mathematical model of a three-phase nonlinear transformer is suggested. The model enables simulating the transformer operation with allowance for its nonlinearity and covers needs of the relay protection. Our model has been developed on the basis of a mathematical model with phase coordinates, where differential equations are composed by the Kirchhoff's phase-voltage law. Based on this model, we first compose a mathematical model for simulating steady-state operation modes of a transformer, taking into account the asymmetry and nonlinearity of its ferromagnetic core. In this model, the initial values of inductances and mutual inductances of loops are determined from the main phase inductance calculated by the experimentally found no-load current, and their current values are determined from the currents in windings and the magnetic fluxes in legs of the transformer core. The magnetic fluxes are calculated by the nodal-pair method. This improved mathematical model is verified through a comparison between the calculated harmonic components of the phase currents and the experimental results. The harmonic components are calculated with the use of Fourier expansion of the calculated phase currents. Their experimental values are determined with a spectrum analyzer. The calculated and experimental harmonic components of the currents of phase A during no-load and rated-load operation of the transformer are tabulated. The comparison of these results shows that the mathematical model of a three-phase transformer we suggest makes it possible to simulate currents in transformer windings under steady-state operation modes with accuracy acceptable for relay protection. [ABSTRACT FROM AUTHOR]

This work analyzes the electric impedance spectra of liver samples. Nyquist diagrams of experimental samples of different sizes were constructed. Optimal model equivalent electrical circuits of the systems studied were obtained and processed, and the parameters of their components were calculated. Changes in parameters and the tangent of the loss angle were shown. A conclusion was made about the interdependence of the electric field strength and the occurrence of stress, caused by using certain frequencies, on the size of the sample. [ABSTRACT FROM AUTHOR]

Non-Hermitian Hamiltonians effectively describing the physics of open systems have become an important tool in various physical platforms, such as photonics, mechanical systems, and electric circuits. The study of non-Hermitian states in electric circuits is developing rapidly recently and forming the field of topoelectrical circuits. Here, we report on the theoretical realization of a higher-order exceptional points (EPs) topological circuit induced by gain and loss. It is shown that, by tuning the value of the positive and negative resistors in the circuit, EPs can collide and merge leading to higher-order singularities. We observe the different energy-difference conserving dynamics near the EPs and the enhanced sensitivity at higher-order EPs. Our results show a way to get higher sensitivity in a non-Hermitian electrical circuit. [ABSTRACT FROM AUTHOR]

Modal and frequency response analysis of the piezoelectric energy harvester utilizing the auxetic booster has been performed in this paper. This harvester has composed of a cantilever, auxetic substrate, and piezoelectric layer. The influence of the piezoelectric's electrical circuit and the harvester's geometrical properties on the fundamental natural frequency, output voltage, and harvested power of the energy harvester have been investigated. The electrical circuit of this electromechanical system consists of a resistor that influences the energy harvester's output voltage and harvested power. A comprehensive parametric study has been performed to find the optimum resistor of the energy harvester. All the analysis has been performed using the finite element method. Mesh size sensitivity analysis of the models is presented, and the finite element model is verified by previous experimental studies. Furthermore, the effect of this energy harvester's damping ratio on the system's outputs has been investigated. The results show that the system's output alters considerably in different damping ratios, and it is necessary to determine the system's damping ratio of the system. The damping ratio of the auxetic energy harvester has been measured through the experimental investigation. The present study illustrates that harvested power of a trapezoidal auxetic energy harvester in resonant frequency could improve by 260 percent by utilizing the optimum resistor. Also, increasing the auxetic booster's thickness could improve the output voltage and harvested power by 48 percent and 22 percent. [ABSTRACT FROM AUTHOR]

In this work, a mathematical model of a three-phase nonlinear transformer is suggested. The model enables simulating the transformer operation with allowance for its nonlinearity and covers needs of the relay protection. Our model has been developed on the basis of a mathematical model with phase coordinates, where differential equations are composed by the Kirchhoff’s phase-voltage law. Based on this model, we first compose a mathematical model for simulating steady-state operation modes of a transformer, taking into account the asymmetry and nonlinearity of its ferromagnetic core. In this model, the initial values of inductances and mutual inductances of loops are determined from the main phase inductance calculated by the experimentally found no-load current, and their current values are determined from the currents in windings and the magnetic fluxes in legs of the transformer core. The magnetic fluxes are calculated by the nodal-pair method. This improved mathematical model is verified through a comparison between the calculated harmonic components of the phase currents and the experimental results. The harmonic components are calculated with the use of Fourier expansion of the calculated phase currents. Their experimental values are determined with a spectrum analyzer. The calculated and experimental harmonic components of the currents of phase A during no-load and rated-load operation of the transformer are tabulated. The comparison of these results shows that the mathematical model of a three-phase transformer we suggest makes it possible to simulate currents in transformer windings under steady-state operation modes with accuracy acceptable for relay protection.

This exploratory study compares how young people (ages 15–16) learn circuitry concepts and layout design principles important to electrical engineering using one of two educational circuitry toolkits: paper circuits and traditional solderless breadboards. Paper-based prototyping kits are representative of a trend that incorporates new materials and approaches to integrating arts into traditional STEM disciplines. Extending prior research on how non-traditional toolkits enhance learning of electrical engineering outcomes, including basic circuitry concepts (i.e., current flow, polarity, and connections), this study examines the material affordances and design choices of the kits that contribute to youth's understanding of more advanced circuitry layout design principles, including space allocation, placement of electronic components, and routing. Results indicate that paper circuits better afford the learning of layout design principles for printed circuit boards (PCBs) with large effect sizes. This study illuminates how the materials of educational toolkits uniquely solicit body- and material-syntonic patterns of activity, and thus differentially engage learners' powerful ideas around circuitry and design principles. This investigation encourages careful consideration of the material affordances of some toolkits over others for learning purposes. [ABSTRACT FROM AUTHOR]

In the present paper the application of the Laplace transform and its inverse transform for solving ordinary differential equations with constant coefficients and initial condition is considered. The solution of an ordinary differential equation that describes a serial RLC circuit is provided. Some results of the simulations are also given. [ABSTRACT FROM AUTHOR]

Laser Induced Plasma Assisted Ablation (LIPAA) has the advantages of economy, environmental friendliness, and high efficiency in the preparation of glass surface metallization. The feasibility of realizing metallized pattern circuit by using LIPAA process on glass substrate with metal copper as sacrificial target under nanosecond laser is studied. Therefore, firstly, the conductivity of metallized pattern circuit on glass substrate prepared by progressive scanning LIPAA is discussed in detail. In view of the disadvantage of the reduction of its conductivity caused by oxidation, the hydrogen reduction was further used to optimize its post treatment, and the circuit performance was analyzed by combining Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy (EDS), revealing the morphology characteristics and the change rule of resistivity of the surface of the glass metallized pattern circuit prepared by nanosecond laser LIPAA method. The results show that the metal layer on the glass surface can be directly ablated by the laser patterning removal process, and the fine patterned circuit can be prepared on the glass surface. At the same time, the chemical hydrogen reduction method can overcome the disadvantage that the metal layer oxidation seriously affects the circuit resistivity. The average resistivity after chemical hydrogen reduction is only 8.18 X 10-7Ω·m, which greatly improves the conductivity of the patterned circuit on the glass surface, shows broad application prospects. [ABSTRACT FROM AUTHOR]

Background. Topicality of the topic an important device of the aircraft air conditioning system is the automatic pressure control system for the pressurized cabin, which includes a number of devices, but one of the main ones is the exhaust valve. The electromechanism of the aircraft pneumatic valve includes two brushless electric motors that control the damper, with rotor position sensors based on a magnetically controlled Hall effect microcircuit. inside the electronic control and monitoring unit of the pneumatic valve as close as possible to the object of protection, i.e. the Hall sensor. The pneumatic valve must pass the test for susceptibility to transients caused by lightning, according to the qualification requirements KT-160D in category A3, which means the third level contact test. A protection element was chosen in the form of a TVS diode (voltage limiter), which is installed in the power circuits and on the logic signal lines from the Hall sensors. Materials and methods. An electrical circuit of lightning protection against transients on the domestic element base has been developed, its practical implementation in the form of a printed circuit assembly for installation in the pneumatic valve electromechanism has been presented. The operation of the lightning protection circuit against transients was simulated in the Multisim software package, for which SPICE models of domestic elements and a microsecond pulse generator circuit were developed. Results and conclusions. The simulation results of the pneumatic valve lightning protection confirmed the operability of the proposed solution.

Background. Reliable operation of in-core neutron detectors improves the quality of measurement data processing and make fields of the neutron and power distributions in the nuclear reactor core more efficient. Materials and methods. The article discusses a new method for monitoring the technical condition of self-powered neutron detector (SPND) that is used to measure neutron flux in the nuclear reactor core. The method is based on the measurement of current values of the detector measuring circuit under steady and dynamic conditions. To monitor the state of this neutron detector, it is proposed to determine not only the insulation resistance of the measuring cable, as it is done in traditional methods, but also the generating capacity of the detector emitter. In addition to the given diagnostic parameters, a new diagnostic feature of the controlled object – capacitance of the measuring circuit of the reactor – has been is introduced in this article. Results and conclusions. Determination of the generating capacity of SPND emitter significantly (by 3–4 orders of magnitude) extends the operating range of the detector by the permissible insulation resistance value (less than 106 Ohms). At the same time, we obtain a new method to estimate the degree of electron emitter burnup caused by neutron flux and to monitor the technical condition of detector by the magnitude of its sensitivity to this flux, which increases the reliability of SPND. Determining the capacitance of the measuring cable of the electrical circuit allows you to properly consider this value when measuring the current signal of the activation detector in order to find the reactor neutron flux under the transient modes of operation.

The way biological systems respond to changes in parameter values caused by mutations is a key issue in evolution and quantitative genetics, as it affects fundamental aspects such as adaptation, selective neutrality, robustness, optimality, evolutionary equilibria, etc. We address this question using the enzyme-flux relationship in a metabolic network as a model of the genotype-phenotype relationship. The lack of a suitable mathematical tool from biochemical theory to investigate this relationship led us to use an analogy between electrical circuits and metabolic networks with uni-uni reactions. We show that a behaviour of diminishing returns, which is commonly observed at various phenotypic levels, is inevitable, irrespective of the complexity of the system. We also present a possible generalization to metabolic networks with both uni-uni and bi-bi reactions., Competing Interests: We declare we have no competing interests., (© 2024 The Author(s).)

The paper proposes an algorithm to determine a method for an optimal starting of the induction motor. The algorithm is demonstrated by comparing on four simple types of the induction motor starting: direct-on-line starting, star-delta starting, starting with an additional resistance and inductance. The algorithm is based on a comparison of results of a numerical simulation of the starting processes of the induction motor. The dynamic curves are drawn for the stator current, rotor speed and electromagnetic torque of the induction motor. For the starting methods using an additional resistance and inductance, curves of the dependence of the corresponding values on the size of an additional resistance and inductance are drawn. They are calculated by using a classical model of the induction motor in the u and v axis. The transient time, average current and average power of the induction motor are used as comparison criterion. To define the optimal starting method, the relative estimations method is used. For the considered example, the starting method of the induction motor with an additional inductance is optimal. [ABSTRACT FROM AUTHOR]

Considered in this paper are mathematical models of mechanics together with the theory of electrical circuits, and their similar dynamical structure is revealed. Using basic analogies, a chain of mechanical springs and an equivalent electrical analogue are constructed. Examples of "successful" borrowings are given, when methods of the theory of electrical circuits may be used to solve stabilization problems for a mechanical system formed by a set of interconnected mechanical subsystems. [ABSTRACT FROM AUTHOR]

This article presents the process of 81 8-year-old children investigating which compo- nent of an electrical circuit is faulty (a burned-out light bulb). The research was carried out in groups of three and was qualitative in nature. Dewey's (1988) complete act of thinking was used to analyse children's behaviour. The ways in which pupils behave at the stage of familiarisation with the problem, hypothesis formation, hypothesis verification and the stage of finding the final solution to the problem were discussed. Attention was paid to children's capabilities and limitations and conclusions were drawn for further research. [ABSTRACT FROM AUTHOR]

The classical Cayley-Hamilton theorem is extended to fractional different order linear systems. The new theorems are applied to different orders fractional linear electrical circuits. The applications of new theorems are illustrated by numerical examples. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the research of solar energy issues, namely to increase the efficiency of solar panels and to compare the performance of solar panels in different configurations. The author researches and compares the performance of solar panels with and without trackers. The sun is an inexhaustible source of energy that mankind has yet to appreciate. Solar energy is the kinetic energy of radiation (mainly light) generated by thermonuclear reactions in the bowels of the sun. Solar energy is one such alternative, the neglect of which will in the near future lead to catastrophic consequences for humanity. Solar energy is a progressive method of obtaining various types of energy through solar radiation. Solar energy is one of the most promising and dynamic renewable energy sources (RES). Each year, the increase in commissioned capacity is approximately 40-50%. In the last fifteen years alone, the proportion of solar electricity in the world has exceeded the 5% mark. To increase the efficiency of solar panels, designers and engineers are developing new devices and devices, one of which is a solar tracker. A solar tracker is a device that allows you to control the movement of the sun across the sky, as well as move the solar panel to the position where the absorption of sunlight is most effective. After the conducted experiment , calculations an comparison we can see the next results. Without the solar tracker our panel generated maximum power in 2.4 Watt. After the solar tracking system integration, our panel generated almost 20 (19.8) Watt of power! After this comparison we can tell that the generated power increase in 8.25 Watts. We can also admit that the amount of generated power depends on light intensity. But solar panels are the most effective when the solar beam falls perpendicular to solar cell and solar panel is at an angle of 75 – 85 degrees

The positivity and cyclicity of descriptor linear electrical circuits with chain structure is considered. Two classes of descriptor linear electrical circuits are analyzed. Some new properties of these classes of electrical circuits are established. The results are extended to fractional descriptor linear electrical circuits. [ABSTRACT FROM AUTHOR]

Electrostatics and constant current circuits are traditionally discussed without their connection being clearly evident. The conceptual framework and analytical operational methods developed in the study of electrostatics are not used in circuit analysis. In order to bring these two fields of study closer together, a circuit consisting of a battery and conducting wires will be examined where the surface distribution of charge takes center stage in the causal relationship when investigating the emergence of electric current. This allows the use of knowledge about the interaction of electric charges to be employed in the understanding of the physical processes occurring in the circuit components as the connections are established. By examining the circuit in this fashion, the spectrum of problems that can be discussed within the same content is broadened. [ABSTRACT FROM AUTHOR]

Based on theoretical ideas about different plasma processes in Nature and Solar, for example of Solar flares, a conceptual model approach is proposed based on the analogy of the flash flow with processes in an electrical circuit. Quite close in a number of parameters to the flashes are the processes of evolution of plasma objects in the "Plasma focus" setup. Based on the physical similarity of processes of this hind, patterns have been studied that make it possible to trace the change in plasma temperature depending on changes in the operating parameters of the setup. The parameters of the model corresponding to the maximum approximation to the conditions of the flash process are revealed. A program has been developed, calculations and analysis of the dependence of the plasma temperature on the parameters of the setup have been carried out: gas mass, velocity of incoming particles, load resistance in the plasma focus. It is shown that the physical model of a solar flare "Electric Circuit" can be implemented on the basis of an operating plasma focus setup, taking into account the scaling of processes. [ABSTRACT FROM AUTHOR]

On the basis of the classical theory of robust control, the theory of stability and the theory of continued fractions, the linearized mathematical model, the procedure for calculating and designing an analog electrical circuit of the H∞-suboptimal robust controller of the flux-linkage control system of the rotor of an asynchronous electric drive, protected by Ukrainian Patent no.137157, were built. The circuit contains three operational amplifiers, several resistors and capacitors. The proposed mathematical model, the procedure for calculating and choosing the parameters of the resistors and capacitors of the circuit take into account the random variations of the object and the controller within the specified boundaries. An analytical relationship between the transfer function coefficients and the resistances of the resistors and the capacitances of the capacitors of the controller's electrical circuit was established. On a specific example, by calculation according to the developed algorithm, the limiting values of the tolerances of the circuit's resistances of the resistors and capacitances of the capacitors were identified and these values were selected with a margin from the standard series. Analysis of noise filtering by the electrical circuit of the controller in the Multisim package shows its insensitivity to noise spreads within fairly wide boundaries.

Nowadays, most students are familiar with the notebook for daily use. The compactness and flexibility of the notebook offer more benefits than a PC. The teachers can engage it during teaching physics. Hence, this research had developed an electrical circuit virtual experiment that acts like real experiments. It can be accessed easily by students in their notebook. This study introduces a flash-based animation Circuit Builder as a simulation designed to help students understand the electrical circuit. This study's purposes were: (1) to analyze the feasibility level of Circuit Builder for enhancing students’ electrical circuit mastery and (2) to know the effectiveness of Circuit Builder based on students’ electrical circuit mastery. Circuit Builder was developed by 4D (Define, Design, Develop, and Disseminate) model. The feasibility level was analyzed by CVI (Content Validity Index). Then, the effectiveness was tested with effect size. This study proved that the virtual laboratory "Circuit Builder” was feasible in physics class with a moderate effect size. The virtual laboratory could improve students’ electrical circuit mastery than doing practices with traditional laboratories.

The students need a learning strategy that is compatible to develop electrical circuit problems completion. Additionally, problem-solving strategy (epistemic game) will develop a learning process that can stimulate the completion of physics. This case encourages the researcher to determine the epistemic game of moderate physics-capable students in solving electrical circuit problems. Moreover, it is qualitative research, and the participant of the research is the students who learn the electrical circuit. Moderate physics-capable students (4 moderately capable students out of 13 students) based on their physics understanding test results. Test and interview were used by the researcher to collect data. The test consists of a physics understanding test and an electrical circuit test. The physics understanding test is used to determine the level of students’ physics understanding, while the electrical circuit test is used to determine students’ epistemic games to solve the problems. The research finding showed the epistemic game of moderate physics-capable students was obtained from the analysis result of the electrical circuit test and interview. The analysis result of the first test, the second test, the third test, and the seventh test showed that the game used to solve problems was transliteration to mathematics. Meanwhile, the students used mapping mathematics to meaning and transliteration to mathematics to solve the problems in the fourth test. The analysis result of the fifth test and the eight test showed that the students used mapping mathematics to meaning to solve the problems. Furthermore, the sixth test was completed by mapping meaning to mathematics.

The classical Cayley–Hamilton theorem is extended to fractional different order linear systems. The new theorems are applied to different orders fractional linear electrical circuits. The applications of new theorems are illustrated by numerical examples.

The positivity and cyclicity of descriptor linear electrical circuits with chain structure is considered. Two classes of descriptor linear electrical circuits are analyzed. Some new properties of these classes of electrical circuits are established. The results are extended to fractional descriptor linear electrical circuits.

This paper presents a novel method to estimate the power consumption of distinct active components on an electronic carrier board by using thermal imaging. The components and the board can be made of heterogeneous material such as plastic, coated microchips, and metal bonds or wires, where a special coating for high emissivity is not required. The thermal images are recorded when the components on the board are dissipating power. In order to enable reliable estimates, a segmentation of the thermal image must be available that can be obtained by manual labeling, object detection methods, or exploiting layout information. Evaluations show that with low-resolution consumer infrared cameras and dissipated powers larger than 300 mW, mean estimation errors of 10% can be achieved. [ABSTRACT FROM AUTHOR]

Excitable cochlear hair cells convert the mechanical energy of sounds into the electrical signals necessary for neurotransmission. The key process is cellular depolarization via K+ entry from K+‐enriched endolymph through hair cells' mechanosensitive channels. Positive 80 mV potential in endolymph accelerates the K+ entry, thereby sensitizing hearing. This potential represents positive extracellular potential within the epithelial‐like stria vascularis; the latter potential stems from K+ equilibrium potential (EK) across the strial membrane. Extra‐ and intracellular [K+] determining EK are likely maintained by continuous unidirectional circulation of K+ through a putative K+ transport pathway containing hair cells and stria. Whether and how the non‐excitable tissue stria vascularis responds to acoustic stimuli remains unclear. Therefore, we analysed a cochlear portion for the best frequency, 1 kHz, by theoretical and experimental approaches. We have previously developed a computational model that integrates ion channels and transporters in the stria and hair cells into a circuit and described a circulation current composed of K+. Here, in this model, mimicking of hair cells' K+ flow induced by a 1 kHz sound modulated the circulation current and affected the strial ion transport mechanisms; the latter effect resulted in monotonically decreasing potential and increasing [K+] in the extracellular strial compartment. Similar results were obtained when the stria in acoustically stimulated animals was examined using microelectrodes detecting the potential and [K+]. Measured potential dynamics mirrored the EK change. Collectively, because stria vascularis is electrically coupled to hair cells by the circulation current in vivo too, the strial electrochemical properties respond to sounds. Key points: A highly positive potential of +80 mV in K+‐enriched endolymph in the mammalian cochlea accelerates sound‐induced K+ entry into excitable sensory hair cells, a process that triggers hearing.This unique endolymphatic potential represents an EK‐based battery for a non‐excitable epithelial‐like tissue, the stria vascularis.To examine whether and how the stria vascularis responds to sounds, we used our computational model, in which strial channels and transporters are serially connected to those hair cells in a closed‐loop circuit, and found that mimicking hair cell excitation by acoustic stimuli resulted in increased extracellular [K+] and decreased the battery's potential within the stria.This observation was overall verified by electrophysiological experiments using live guinea pigs.The sensitivity of electrochemical properties of the stria to sounds indicates that this tissue is electrically coupled to hair cells by a radial ionic flow called a circulation current. [ABSTRACT FROM AUTHOR]

Background. The aim of the article is to develop a methodology to determine parameters of three-element resonant electric circuits based on resonant frequency and quality factor measurements. Materials and methods. The proposed technique provides for the measurement of resonant frequency, quality factor, and maximum voltage at the output of a measuring circuit with subsequent solution of a system of equations connecting the measured parameters with inductance, capacitance, and active resistance of the electrical circuit. Results. Calculated ratios are given, and an example of determining the parameters of a specific three-element resonant electric circuit, and estimating the error component due to imperfection of an operational amplifier, with a measuring circuit built thereon, is considered. Conclusions. An application of the proposed technique to determine the parameters of resonant electrical circuits based on resonant frequency and quality factor measurements made it possible to get rid of errors in analogue conversions of the output voltage of the measuring circuit. According to the simulation results, the error component does not exceed 1 % due to imperfection of the element base of the measuring circuit.

The cyclicity of the state matrices of positive linear electrical circuits with the chain structure is considered. Two classes of positive linear electrical circuits with the chain structure and cyclic Metzler state matrices are analyzed. Some new properties of these classes of positive electrical circuits are established. The results are extended to fractional linear electrical circuits. [ABSTRACT FROM AUTHOR]

Structurally R-controllable and structurally R-observable descriptor linear electrical circuits are investigated. Sufficient conditions are given under which the Rcontrollability and R-observability of descriptor linear electrical circuits are independent of their parameters. [ABSTRACT FROM AUTHOR]

Purpose. Determination of the possibility of using the developed autonomous voltage divider for measuring high-voltage pulses with sharpened fronts (down to 1 ns). Methodology. We use the technique to determine the division ratio of the divider using a calibrated oscillator and oscilloscope. To determine the rise time of the transition characteristic of the divider, we use an experimental technique based on a high-voltage pulse generator with a steep front and computer simulation using circuit program Micro-Cap. Results. Oscillograms of high-voltage nanosecond pulses with subnanosecond fronts are experimentally obtained using an autonomous resistive voltage divider. A computer simulation of the operation of the created divider in various modes is carried out. Originality. We have shown that an autonomous shielded resistive high-voltage voltage divider can have a rise time less than 1 ns. The values of the parasitic parameters of the divider, which lead to a distortion of the sharpened pulse front with a rise time of ≈0.1 ns, are established. Practical value. The divider can be used to measure the characteristics of high-voltage pulses with a steep front (up to 1 ns as the lower limit).

This study presents a modelling for the carotid artery that allows to analyze the theoretical behavior of pressure, flow and arterial volume in it, from the variation of both physical and physiological characteristics, such as: the thickness and length of the vessel blood, the viscosity and density of blood; determinants in the study of the normal functionality of the artery. The model of the arterial vessel –an adaptation of the Windkessel model of three elements, reported by Westerhof and Stergiopulos–, consists of an electrical circuit composed of passive RLC elements. The arterial segment was analyzed by mathematical and computational tools, relating Poiseuille's laws and electric laws. The pressure, flow and volume curves were obtained when changes occurred in the measurable characteristics of the carotid artery, in order to facilitate the medical interpretation of possible pathologies related to these changes.

The cyclicity of the state matrices of positive linear electrical circuits with the chain structure is considered. Two classes of positive linear electrical circuits with the chain structure and cyclic Metzler state matrices are analyzed. Some new properties of these classes of positive electrical circuits are established. The results are extended to fractional linear electrical circuits.

This paper is dedicated to the research of solar energy issues, namely to increase the efficiency of solar panels and to compare the performance of solar panels in different configurations. The author researches and compares the performance of solar panels with and without trackers. The sun is an inexhaustible source of energy that mankind has yet to appreciate. Solar energy is the kinetic energy of radiation (mainly light) generated by thermonuclear reactions in the bowels of the sun. Solar energy is one such alternative, the neglect of which will in the near future lead to catastrophic consequences for humanity. Solar energy is a progressive method of obtaining various types of energy through solar radiation. Solar energy is one of the most promising and dynamic renewable energy sources (RES). Each year, the increase in commissioned capacity is approximately 40-50%. In the last fifteen years alone, the proportion of solar electricity in the world has exceeded the 5% mark. To increase the efficiency of solar panels, designers and engineers are developing new devices and devices, one of which is a solar tracker. A solar tracker is a device that allows you to control the movement of the sun across the sky, as well as move the solar panel to the position where the absorption of sunlight is most effective. After the conducted experiment, calculations an comparison we can see the next results. Without the solar tracker our panel generated maximum power in 2.4 Watt. After the solar tracking system integration, our panel generated almost 20 (19.8) Watt of power! After this comparison we can tell that the generated power increase in 8.25 Watts. We can also admit that the amount of generated power depends on light intensity. But solar panels are the most effective when the solar beam falls perpendicular to solar cell and solar panel is at an angle of 75 – 85 degrees. [ABSTRACT FROM AUTHOR]