Electrical Analog Research Articles

Historical Stages of Musical Art Development in the Context of Scientific and Technical Progress

The purpose of the work is to define the historical milestones of scientific and technological progress and to identify the interrelationship of art, technique, and technology at various stages of world culture development. The research methodology is based on philosophical and aesthetic research on the evolution of artistic culture and the understanding of the musical-communicative process, which allows the summing up and substantiating of the conclusions of the outlined issues. The scientific novelty of the work consists in gradually highlighting the historical stages of the scientific and technical revolution, demonstrating its direct influence on the development of musical art from the first stages of its development to the present day. It has been determined that in each historical formation, transformational processes are closely related to scientific and technical progress, which today are the main driving force of the musical and technical industry. Conclusions. The first stage is marked by the emergence of writing, which destroyed the monopoly of a small number of people on knowledge. At this stage, musical notation appears, with the help of which the information related to music is broadcasted. In the second stage, the invention of the printing press becomes a means of rapid dissemination of information, including musical information, through sheet music printing. The third stage is associated with the invention of mechanical sound recording and sound reproduction devices, as well as the introduction of electric current and analogue sound recording devices. In the fourth stage, because of modern technological achievements, the so-called phenomenon of "digital arts" is formed, which is characterised by interactivity, elitism, a new genre system, and innovative means of artistic expression. Modern artistic technologies, relying on the latest sound processors, computer software, and other digital innovations, help to expand the boundaries and create a new sound palette in music and concert practice, theatre performances, studio work, radio broadcasting, screen arts, and other areas of cultural and artistic life. Key words: musical art, scientific and technical progress, information revolutions, computer technologies, digital arts

A triboelectric nanogenerator attached to a thermoacoustic heat engine for power generation

Thermoacoustics is a promising field that uses the phenomena of acoustic wave interaction with neighboring solid boundaries to build engines for power generation. A typical thermoacoustic heat engine (THE) converts heat from an input source to acoustic energy, which is then collected by an alternator to generate electricity. Moving parts are present in an alternator, rendering it expensive and less reliable. A viable alternative is the use of Triboelectric nanogenerators (TENG) as a conversion system. Thus, a thermoacoustic heat engine integrated with a TENG is modeled and analyzed in this paper. A three-tier methodology including analytical, FEM, and an electrical analogy approach is adopted to simulate and optimize the performance of a TENG-attached-THE. The simulation results show that a voltage and current of 11.2 V and 0.028μA, respectively, are produced, differing by + 1.2 V and + 0.013μA with the experimental results.

Time-domain acoustic-electrical analogy investigation on a high-power traveling-wave thermoacoustic electric generator

Thermoacoustic electric generator is a novel heat-to-power conversion technology with potential high efficiency and reliability, showing great potential in distributed power generation. In this paper, we conduct time-domain acoustic-electrical analogy investigations on a high-power 4-stage looped traveling-wave thermoacoustic electric generator to shed lights on the system performance. The components of a thermoacoustic system are simplified as an acoustic–electrical analogy model, thus saving computational time. Additionally, the nonlinear effects in the regenerator, heat exchanger and resonance tube are considered in establishing the time-domain equations. Method validation shows a reasonable agreement between experimental and simulated results. Transient evolutions of the oscillating pressure and volume flow rate are firstly given. Investigation is then conducted on onset temperature using different working gases of helium, argon, nitrogen, and neon. The results indicate that when the external resistance reaches 70 Ω, the minimum onset temperature difference of 112 K can be achieved with argon as the working gas. For steady-state characteristics, the influences of electric resistance and heating temperature are explored. It is found that higher heating temperature contributes to larger electric power. A large electric resistance results in a large electric resistance at high heating temperature, while the highest efficiency is achieved with a medium electric resistance. Furthermore, higher heating temperature can lead to more irreversible losses. With helium employed, a maximum electric power of 13.3 kW with thermal-to-electric efficiency of 27.4% is achieved with an electric resistance of 150 Ω and a heating temperature of 950 K, and a highest thermal-to-electric efficiency of 33.5% with electric power of 1.38 kW is obtained when the electric resistance and heating temperature are 90 Ω and 750 K, respectively. This study shows that the proposed method provides a new perspective and an effective method for understanding thermoacoustic electric generator.

Probability-Density-Dependent Load Frequency Control of Power Systems With Random Delays and Cyber-Attacks via Circuital Implementation

This paper studies the decentralized <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> secure load frequency control issue and circuital realization of multi-area networked power systems subject to random transmission delays and deception attacks. To make full use of the stochastic feature of the network-induced transmission delay, its distribution described by the probability density function is utilized. Due to this feature, the normal control signal and the injected deceptive attack signal transmitted over the network can be formed as two distributed delay terms. Then, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$i$ </tex-math></inline-formula> th load frequency control area is established as a new distributed delay system, in which the delay probability density is treated as the distributed kernel. By utilizing an integral inequality dependent on the kernel, new sufficient controller design conditions are derived to guarantee the system stability with given <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> performance. Moreover, a physical execution approach is addressed to transfer the load frequency control systems into electrical analogy circuits. The effectiveness of the proposed approach is illustrated via the professional simcape toolbox in Simulink/MATLAB for circuit simulations.

A coupled hydraulic–thermal dynamic model for the steam network in a heat–electricity integrated energy system

Steam is the most common heat support medium in an industrial park's heat–electricity integrated energy system (HE-IES). The steam network (SN) has excellent time delays and heat storage capacity compared to the grid. However, regarding the HE-IES scheduling, previous studies ignored the dynamic delay characteristics of the hydraulic–thermal calculation processes in the SN and the time delays between the SN and the grid when they were operated concurrently. Thus, this paper proposes an improved method of characteristics to incorporate the dynamic hydraulic–thermal processes and quantify the dynamic offsets. To solve the time asymmetry problem associated with the grid, the SN is modeled by a thermal -electrical analogy model and graph theory. The effectiveness of the proposed model was verified by actual SN operating data, and less than 9% relative error between the model outputs and actual results was obtained. The model can satisfy the HE-IES operation requirements with high accuracy. Moreover, in contrast to a thermodynamic process, the hydraulic process can be regarded as a transient process. A generic delay time–distance formula is fitted and applied in the expression of the thermodynamic processes to better improve the HE-IES operations.

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Telling the Wave Function: An Electrical Analogy

The double nature of material particles, i.e., their wave and corpuscular characteristics, is usually considered incomprehensible, as it cannot be represented visually. It is proposed to the student, in introductory courses, as a fact justified by quantum interference experiments for which, however, no further analysis is possible. On this note, we propose a description of the wave function in terms of a simple electrical analogy, which reproduces at least some of its essential properties. Our aim is to provide a cognitive representation of an analogical type: starting from a classical context (electrical circuits) and introducing in an appropriate way the notions of “wave” and “particle”, we show how typically quantum properties such as delocalization and entanglement emerge in a natural, understandable, and intuitive way.

Analysis of the sound absorption characteristics of the curved microperforated panel with elastically restrained edges

This paper describes the analytical and experimental study on the sound absorption characteristics of the curved microperforated panel (CMPP) with elastically restrained edges backed by an air cavity. The arbitrary boundary conditions are realized by setting the restrained spring at the edges to zero or infinite. The acoustic impedance formula of the CMPP is derived based on the modal superposition method. The acoustic electrical analogy method is used to obtain the sound absorption coefficient of the CMPP, in which the effects of the structural parameters on the sound absorption coefficient such as aspect ratio, radius of curvature, perforation rates, micro holes diameters and panel thicknesses are also studied. To validate the accuracy of the present method, the impedance tube test system is designed to measure the sound absorption coefficient under different micro holes diameters and panel thicknesses. The results derived by the analytical method and the test one match well with each. This paper provides a new kind of sound absorption structures which could be used in the health environment.

Impact of superconducting fault current limiters on Delayed Current Zeros in industrial power systems

Electric power systems may exhibit fault currents with high asymmetry when generators are close to large motors and loads. In this condition and depending on the fault inception instants, the fault current waveforms may present Delayed Current Zeros (DCZ). During transient studies, in some cases, breakers do not see the current zero-crossing for several cycles. Indeed, if the breaker opens just after a transient when the current has not reached steady-state and may be offset by a slow exponentially decaying DC component, then, the breaker will fail to open as the current will not cross zero within the interruption time. Here, the main concern associated with DCZ is however related to the interruption of the circuit breakers on a current wave crossing zero. At this moment, the interruption is accompanied of an electrical arc having the potential to damage equipment. Resistive superconducting fault current limiters (r-SFCL) are a known solution to reduce the magnitude of short-circuit current in electrical systems. It is a versatile technology that can tackle both fault and stability issues in aging and modern power grids alike. As a side benefit, it may also address the DCZ problem. The present work aims at investigating the impact that an r-SFCL may have on DCZ and, in particular, its ability to eliminate this issue altogether. To that end, a r-SFCL based on an existing design was modeled using the consolidated thermal–electrical analogy. This approach has proven to be fairly accurate to model the transient behavior of the superconducting device. Here, the case study simulates a solid short-circuit at the terminal of a generator in a specific bus, simulating an industrial power system, that includes a circuit breaker, a motor load, and a r-SFCL. The electromagnetic transient computations were carried out considering load and no-load conditions with and without the r-SFCL. Eight scenarios were considered, showing that r-SFCLs can actually address DCZ in addition to limit the fault level.

Wave analysis and control of uniformly varying two-dimensional ladder-network structures

This study investigates the wave analysis and control of two-dimensionally (2D) connected ladder networks. These networks describe the out-of-plane vibration of 2D arrayed masses, according to the mechanical–electrical analogy. One typical correspondence to continuous systems is the out-of-plane vibration of membranes. In the analysis, the emphasis is on the properties of the secondary constants–propagation constants and characteristic impedances (admittances)–as analytic functions of the Laplace transform variable s. The system can be treated as a cascade connection of layers comprising the lateral direction elements, varying uniformly by a constant ratio along the longitudinal direction. In addition, the system dynamics can be described by a first-order recurrence relation in the Laplace transform domain. The characteristic polynomial defining the propagation constants can be defined independently of the layer position, even for the uniformly varying case. It can be decomposed into second-order polynomials characterized by a characteristic constant. We demonstrate that, above a threshold, all the constants are different and real, revealing several properties of the secondary constants and transformation matrix required for the wave analysis and control. These properties are also useful for a rational implementation of the impedance matching controller. Numerical examples illustrate the derived results and effectiveness in vibration control.

Nexus Between Human Thermoregulation and Cardiovascular Functions—A Preliminary Simulation for a Moderate Variation of Temperature

AbstractThough the interaction between cardiovascular functions and thermoregulation is enormously complex yet immensely important, very little effort to date has been spent to simulate it from a system point of view. The present work aims at simulating the mutual interaction of human thermoregulation and cardiovascular functions by combining simple models of these two systems. While for thermoregulation, a lumped parameter multi-node model has been developed, a SIMULINK-based approach of electrical analogy has been taken for the cardiovascular system. These two models are coupled by different physiological and control actions, represented by well-established correlations. Three case studies have been conducted. In the first case, thermoregulation of a healthy human being is considered for a prescribed temperature cycle of moderate variation. Under heat stress, cardiac output increases by a joint effect of heart rate and stroke volume while under the cold condition, the variation of the cardiac output is less and is primarily governed by the heart rate. For the case of a reduced ejection fraction of the left ventricle, though there is a notable decrease in skin blood flow, negligible variation in skin and core temperature is observed. In the case of acute aortic stenosis, it is found that the blood pressure falls severely from its normal level causing hypotension and is further aggravated even under moderate heat stress. Such a situation might have further consequences like heat stroke. Finally, the limitations of the present study have been highlighted and suggestions have been made for further improvement.

Graph Structure-Based Heuristics for Optimal Targeting in Social Networks

In this article, we consider a dynamic model for competition in a social network, where two strategic agents have fixed beliefs, and the nonstrategic/regular agents adjust their states according to a distributed consensus protocol. We suppose that one strategic agent must identify <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$k_+$</tex-math></inline-formula> target agents in the network to maximally spread his/her own opinion and alter the average opinion that eventually emerges. In the literature, this problem is cast as the maximization of a set function and, by leveraging on the submodularity property, is solved in a greedy manner by solving <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$k_+$</tex-math></inline-formula> separate single targeting problems. Our main contribution is to exploit the underlying graph structure to build more refined heuristics. First, we provide the analytical solution for the optimal targeting problem over complete graphs. This result provides a rule to understand whether it is convenient or not to block the opponent.s influence by targeting the same nodes. The argument is then extended to generic graphs, leading to more effective solutions compared to the greedy approach. Second, we derive some useful properties of the objective function for trees by an electrical analogy. Inspired by these findings, we define a new algorithm, which selects the optimal solution on trees in a much faster way with respect to a brute-force approach and works well also over tree-like/sparse graphs. The proposed heuristics are then compared to zero-cost heuristics on randomly generated graphs and real social networks.

Piezomagnetic switching of the anomalous Hall effect in an antiferromagnet at room temperature

Piezomagnetism couples strain linearly to magnetic order, implying that it can produce and control magnetization. However, unlike magnetostriction, which couples magnetization quadratically to strain, it enables bidirectional control of a net magnetic moment. If this effect becomes large at room temperature, it may be technologically relevant, similar to its electric analogue, piezoelectricity. However, current studies of the piezomagnetic effect have been primarily restricted to antiferromagnetic insulators at cryogenic temperatures. Here we report the observation of large piezomagnetism in the antiferromagnetic Weyl semimetal Mn3Sn at room temperature. This material is known for its nearly magnetization-free anomalous Hall effect. We find that a small uniaxial strain on the order of 0.1% can control both the sign and size of the anomalous Hall effect. Our experiment and theory show that the piezomagnetism can control the anomalous Hall effect, which will be useful for spintronics applications. Control of magnetization is important for applications in spintronics. Now, the piezomagnetic effect allows strain to control the anomalous Hall effect in a metal at room temperature by rotating its antiferromagnetic order.

Modeling dynamics of chemical reaction networks using electrical analogs: Application to autocatalytic reactions

Modeling complex chemical reaction networks has inspired a considerable body of research and a variety of approaches to modeling nonlinear pathways are being developed. Here, a general methodology is formulated to convert an arbitrary reaction network into its equivalent electrical analog. The topological equivalence of the electrical analog is mathematically established for unimolecular reactions using Kirchhoff's laws. The modular approach is generalized to bimolecular and nonlinear autocatalytic reactions. It is then applied to simulate the dynamics of nonlinear autocatalytic networks without making simplifying assumptions, such as use of the quasi-steady state/Bodenstein approximation or the absence of nonlinear steps in the intermediates. This is among the few papers that quantify the dynamics of a nonlinear chemical reaction network by generating and simulating an electrical network analog. As a realistic biological application, the early phase of the spread of COVID-19 is modeled as an autocatalytic process and the predicted dynamics are in good agreement with experimental data. The rate-limiting step of viral transmission is identified, leading to novel mechanistic insights.

Static, Dynamic, and Signal-to-Noise Analysis of a Solid-State Magnetoelectric (Me) Sensor with a Spice-Based Circuit Simulator

Modeling the non-electrical processes by equivalent electrical circuits is a widely known and successfully used technique in research and development. Although finite element methods software development has supplanted electrical analogy techniques due to greater accuracy and intuitiveness in recent decades, the modeling of physical processes based on analogies has several advantages in some cases. Representation of physical processes in the form of lumped circuits and graphs allows researchers to estimate the system with an alternative view, use standardized methods for solving electrical circuits for non-electrical systems, and, most importantly, allows us to use electrical circuit simulators with their unique capabilities. Of particular interest for using the analogy technique are systems that include electronic components along with components belonging to other physical domains, such as mechanical, thermal, magnetic, and others. A solid-state magnetoelectric (ME) sensor equipped with a charge amplifier is proposed in this study as an example of analysis using the equivalent electrical circuit and simulating these circuits using SPICE-based circuit simulators. Sensor analysis is conducted with an emphasis on noise budgeting and optimizing the sensor’s signal-to-noise ratio and resolution. In addition, the steady state, the phasor, and transient types of analyses were employed to study the static and dynamic behavior of the system. Validation of the model using analytical calculations and comparison with experimental data demonstrated superior results.

Circuit-Based Design of Microfluidic Drop Networks

Microfluidic-drop networks consist of several stable drops—interconnected through microfluidic channels—in which organ models can be cultured long-term. Drop networks feature a versatile configuration and an air–liquid interface (ALI). This ALI provides ample oxygenation, rapid liquid turnover, passive degassing, and liquid-phase stability through capillary pressure. Mathematical modeling, e.g., by using computational fluid dynamics (CFD), is a powerful tool to design drop-based microfluidic devices and to optimize their operation. Although CFD is the most rigorous technique to model flow, it falls short in terms of computational efficiency. Alternatively, the hydraulic–electric analogy is an efficient “first-pass” method to explore the design and operation parameter space of microfluidic-drop networks. However, there are no direct electric analogs to a drop, due to the nonlinear nature of the capillary pressure of the ALI. Here, we present a circuit-based model of hanging- and standing-drop compartments. We show a phase diagram describing the nonlinearity of the capillary pressure of a hanging drop. This diagram explains how to experimentally ensure drop stability. We present a methodology to find flow rates and pressures within drop networks. Finally, we review several applications, where the method, outlined in this paper, was instrumental in optimizing design and operation.

Second‐Order Memristor Based on All‐Oxide Multiferroic Tunnel Junction for Biorealistic Emulation of Synapses

AbstractThe brain has the ability to learn and evaluate as it receives and registers information. Signals between neurons are transmitted via synapses whose plasticity is modulated by usage. A bio‐realistic electrical analog is a second‐order memristor, where the short‐term internal dynamics influence the long‐term state. It is achieved here with an all‐oxide multiferroic tunnel junction: La0.7Sr0.3MnO3 / BaTiO3 / La0.7Sr0.3MnO3. Similar to the modulation of synaptic weight by stimuli, multi‐levels of resistance may be encoded by mean of voltage pulses, on long time scale and in correlation with short‐term effects. Neuromimetic learning functions are demonstrated: short and long‐term potentiation/depression, paired‐pulse facilitation/depression, spike‐rate‐ and experience‐dependent plasticity. The threshold frequency of pulse trains at which depression changes into potentiation depends on the previous activity, with a sliding effect as in neurobiology. The voltage pulses induce reversible changes of both dielectric polarization and oxygen vacancies distribution, generating transient trapped/detrapped charges at the two interfaces that govern the dynamic response. The resistance levels are determined by the final cationic ordering (the redox Mn3+/Mn4+ ratio) at the two interfacial layers. The stimulation/relaxation dynamics are close to that in biological counterparts. Such memristors can be used in hardware artificial networks for advanced processing/storage of the information.

Numerical study of a heat-driven thermoacoustic refrigerator based on a time-domain lumped acoustic–electrical analogy model

Thermoacoustic technology is a promising clean energy solution for the recovery of low-grade heat from renewable energy sources and waste heat. Existing methods for simulating thermoacoustic systems are inconsistent or time-consuming. In this study, a time-saving and reliable time-domain lumped acoustic–electrical analogy model is proposed to investigate the performance of thermoacoustic systems. In the proposed model, each component of a thermoacoustic system is simplified as a lumped acoustic–electrical analogy model. The nonlinear effects of both regenerator and liquid acoustic resistances in gas–liquid resonators are considered to obtain nonlinear dynamic evolution equations. Case studies were performed on a looped heat-driven thermoacoustic refrigerator for low-grade heat recovery to investigate its onset and steady characteristics. The evolutions of the oscillating pressure and volume flow rate were explored, which initially increase rapidly until reaching the saturation state. The minimum onset temperature was 32.5 K at a pressure of 2.5 MPa with hydrogen as the working gas. In addition, the influences of the mean pressure, heating temperature, and cooling temperature on the steady-state system performance with various working fluids were investigated. The results indicated that the cooling power increased significantly with increasing mean pressure, heating temperature, and cooling temperature. A higher working liquid density resulted in a lower onset temperature, lower working frequency, and larger pressure ratio. With the use of helium or hydrogen, the refrigerator performed better in terms of a lower onset temperature and a larger pressure ratio, cooling power, and coefficient of performance. The proposed model provides a new perspective and an effective approach to characterise the onset and steady characteristics of thermoacoustic systems.

Mass diffusion in multi-layer systems: an electrical analogue modelling approach

We develop a lumped parameter model to describe and predict the mass release of (absorption from) an arbitrary shaped body of any dimension in a large environment. Through the one-to-one analogy between diffusion-dominated mass transfer systems and electrical circuits we provide exact solutions in terms of averaged concentrations and mass released. An estimate of the equivalent resistance and of the release time is also given, and shown to be inversely proportional to the diffusivity. The proposed electrical analogue approach allows a time constant to be defined and provides an easy extension to a multi-layer and multi-phase cases in planar and spherical geometries. The simulation results are compared with those obtained from the solution of the corresponding analytical, numerical and experimental solutions, showing a satisfactory accuracy and a good agreement.

An Electric Circuit Analogy Model for Analyzing the Relation Between CO and H2 in Interfacial Reduction Reactions

An Electric Circuit Analogy Model for Analyzing the Relation Between CO and H2 in Interfacial Reduction Reactions