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This research presents the design and fabrication of a semi-automatic paper petal compression machine with a pneumatic system to crease paper petals for making artificial flowers. The description comprises the procedures of defining operating characteristics for the machine, drawing its function diagram, designing the pneumatic circuit and the electrical circuit, calculating and choosing the dimensions of pneumatic components, and studying optimum paper petal compression conditions and appearances of creases on the paper petals. The machine can be used to compress the paper petals in four positions at the same time. The experimental materials were the paper of 55 and 65 gsm which was cut in the petal shape. The experiments were done by rolling 6, 8, 10, 12, 14, and 16 pieces of paper petals into hollow cylinders of which four rolls of those with the same number of paper petals were compressed simultaneously at the operating pressure of 0.6 MPa. The results showed that the machine could be used to compress the paper petals of 55 gsm to provide quite noticeable and consistent creases in the range of 6 to 14 pieces per roll, while the paper petals of 65 gsm were in the range of 6 to 12 pieces per roll. [ABSTRACT FROM AUTHOR]

The double layer present at the interface of an electrode and an analyte causes electrode polarization (EP) in impedance spectroscopy, which hinders acquiring the actual impedance of biological samples at a lower frequency region. In this work, a novel carbon paste (CP) electrode material prepared by mixing the pencil graphite powder with transparent glue has been reported to reduce the EP by depositing its two coplanar electrodes on a chromatography paper substrate. Furthermore, two other devices having silver paste and pencil electrodes on the chromatography paper have been fabricated, analyzed for the EP, and compared with the CP electrode. The EP is quantified by fitting the impedance data to an equivalent electrical circuit having double layer capacitance as a constant phase element, and the CP electrode shows the lowest EP among the electrodes. The cyclic voltammetry analysis reveals blocking electrode property of the CP, which diminishes dc current flow at the electrode/electrolyte interface. Furthermore, the chromatography paper is found to increase the effective surface area of the deposited electrode by enhancing its surface roughness, which helps reduce the EP. [ABSTRACT FROM AUTHOR]

Shunt resistance R sh is a critical parameter for photovoltaic cells designed for low light indoor applications because it negatively affects the open circuit voltage, fill factor, and conversion efficiency. Standard CIGS cells are known to have low R sh and are, therefore, unpromising candidates for indoor energy sources. In this paper, we extend the original work of Virtuani et al. by determining the electrical specifications of many CIGS cells with copper contents [Cu]/([Ga]+[In]) as low as 0.33 and gallium contents between 0.28 and 0.81. First, IV data are fitted by a standard single-diode electrical circuit model for each illumination, resulting in light-dependent parameters. Then, we use a procedure based on a single dataset of electrical variables, i.e., independent of light, corrected by the experimental collection function, which captures light-dependent physical mechanisms. In this way, we are able to correctly reproduce the illuminance dependence of the electrical response of the PV cell over three orders of magnitude, in particular with a fixed value of the shunt resistance. The highest R sh is obtained with a low copper composition of 0.5 , regardless of the gallium composition. [ABSTRACT FROM AUTHOR]

Paper-touchpad for the detection of Parkinson's tremor • Paper based flexible touchpad was fabricated. • The resistive touchpad works based on output electrical resistance. • The concept is further extended to developed flexible hand tremor detector. • A prototype was developed to detect the hand tremor for diagnosing neurological disorders such as Parkinson's diseases. A resistive touchpad was developed employing paper, pencil graphite, and polydimethylsiloxane (PDMS). A pair of flexible substrates with one side coated with conducting graphite and the other with insulating polymer, were assembled with the help of an intercalated polymer spacer having holes which, allowed the inner graphitic layers of the paper surfaces to come in contact with each other upon touching or pressing. An external electrical circuit was designed to detect the variations in the output electrical resistances. The resistive pad was further modified to develop a point-of-care-testing (POCT) device to detect the hand tremors associated with the neurological disorders such as Parkinson's disease. The proof-of-concept POCT pad showed variations in the electrical resistance due to the variation in contact area at the inner conductive layers of the paper surface when pressed with a pair of human fingers experiencing tremors. Simplified circuit-models have been discussed to explain the operating principles of the resistive pad and the POCT device. The response from the detection unit helped in evaluating the real time hand tremor levels of patients. The POCT prototype was able to detect the early to chronic stages and severity of tremor and thus is capable of detecting diverse neurological disorders. [ABSTRACT FROM AUTHOR]

The analysis of dielectric response function obtained from the power transformer is a well-accepted technique in insulation diagnosis. A convenient way of analysing time-domain dielectric response φ(t) is the formulation of simple resistance -capacitance-based circuits like the conventional Debye model (CDM) or the modified Debye model (MDM) that are capable of modelling φ(t). However, available techniques do not guarantee unique branch parameters of such circuits for a given φ(t). In fact, the branch parameters are known to depend on the curve-fitting procedure opted during model formulation. This makes accuracy of CDM and MDM parameter-based diagnosis techniques less reliable. Furthermore, it seems logical to analyse the time-domain dielectric response of oil-paper insulation using a model containing time-varying parameters. In this study, a methodology is proposed using which such an insulation model (containing time-varying parameters) is formulated using timedomain insulation response. Related analysis presented suggests that the proposed model is immune to problems associated with available insulation models (containing time-invariant parameters). The performance of the proposed model in indicating insulation condition is tested on data obtained from several real-life power transformers. [ABSTRACT FROM AUTHOR]

In comparison with the AC and DC working voltages, the effect of switching impulse voltage on insulation is very different because of its fast-rising rate and large amplitude. This paper mainly focuses on the characteristics of PD in oil-impregnated paper insulation under switching impulse voltage. First, a robust experimental platform was set up including the impulse power source, test samples with uniform gas and oil gap, and the signal acquisition and processing system. PD characteristics in the air and oil gap are analyzed and compared involving the time-domain waveforms, the variation tendency of the average amplitude and numbers of PD pulses, the occurrence time and the instantaneous value of impulse corresponding to the first PD. Based on the dielectric barrier discharge (filament) theory, a parallel microcircuit model was established to explain the similarities and dissimilarities, and to evaluate the gap discharge intensity. The occurrence and development of PD under switching impulse voltage of typical oil-impregnated paper defect were studied systematically with simulation, experiments, and modeling. [ABSTRACT FROM AUTHOR]

This paper discusses the effect of temperature on polarization and depolarization current measurements on paper oil insulation system. The influence of copper sulphide formed due to corrosive sulphur in mineral oil, on the changes in polarization and depolarization current at different temperatures are considered. A significant increase in the magnitude of polarization and depolarization currents due to deposits of copper sulphide on paper layers is observed. The conductivity of paper insulation increases significantly with increase in temperature. The increase in current is attributed to thermally active conducting particles of copper sulphide. The Debye model parameters of equivalent circuit under copper corrosion have been computed and a model for failure due to copper sulphide is explained using the data on polarization and depolarization currents. [ABSTRACT FROM PUBLISHER]

Turbine systems equipped with doubly fed induction generation (DFIG) are becoming increasingly vital in wind power generation, with the reliability of the devices serving as a pillar in the industrial sector. Thermal stress and lifetime assessment are fundamental indicators in this regard. This paper primarily addresses the thermal stress and lifespan of power semiconductor devices utilized in a DFIG grid-side converter (GSC) and rotor-side converter (RSC). PLECS (Piecewise Linear Electrical Circuit Simulation) is employed to validate the electrical and thermal stress of the power devices. Additionally, Ansys Icepak, a finite element analysis (FEA) software, is utilized to confirm temperature fluctuations under various operations. The power consumption and junction temperature of the power devices in the GSC and RSC of a 2 MW DFIG are compared. It is evident that the most stressed power semiconductor is the IGBT for the GSC with a temperature swing of 3.4 °C, while the diode in the RSC is the most stressed with a temperature swing of 10.1 °C. This paper also presents a lifetime model to estimate the lifespan of the power device based on the annual wind profile. By considering the annual mission profile, we observe that the lifetime of the back-to-back power converter is limited by the diode of the RSC, whose B10 lifetime is calculated at 15 years. [ABSTRACT FROM AUTHOR]

Several existing research studies on the modeling of photovoltaic (PV) systems feeding a resistive load through a DC-DC converter have proven that the use of the small-signal approach using analytical or graphical methods for the design of a linear model is failing. This is due to the fact that the simplified linear model, usually presented by a transfer function, is unable to reveal all the existing information about the actual solar system behavior when subjected to the Standard Test Conditions (STC). Since it does not take into account: (i) the nonlinearity of the current–voltage (I-V) characteristic of the solar panel, (ii) the presence of elementary components in both the solar panel and the DC-DC converter, which are often unmodeled and cannot be easily considered in the modeling, (iii) the existence of extra components in the DC-DC converter and more dynamics that must be neglected at high frequencies, for example those describing the thermal energies dissipated in the IGBT part of the DC-DC boost converter, the presence of cross-coupling between some electrical quantities occurring either in the DC-DC boost converter or in the solar panel, etc. For these reasons, this paper proposes a new design of a small-signal linear model to accurately describe the actual solar system behavior operating at STC. This is achieved by considering its internal functioning as a black box where only its input–output measurements are available in the form of frequency response data (FRD), generated by running a free stand-alone Plecs® software package. As this software has the ability to perfectly model the behavior of boost DC-DC converters, previously connected by variable resistive loads, it is possible thanks to the existence of equivalent electrical circuits, available in its own library. Unfortunately, this library lacks an equivalent circuit for the KC200GT photovoltaic panel where its design is needed through evaluating its current–voltage characteristics. The resulting global model is then simulated in the modified Plecs® software, providing the desired FRDs. These are used to estimate the parameters of the proposed linear model, which then used for tuning the PID controller. Here, this controller is combined with the standard Maximum Power Point Tracking (MPPT) strategy based on the direct implementation of the Incremental Conductance (INC) algorithm, highlighting therefore the proposed improved INC-MPPT strategy. It perfectly overcomes the ripple problems encountered in some electrical components of the solar system when controlled by the standard INC-MPPT strategy. As the proposed improvements depend on the model accuracy, the main contribution of this paper lies therefore on the necessary steps to design this proposed small-signal model. [ABSTRACT FROM AUTHOR]

Many complex engineering systems can be represented in a topological form, such as graphs. This paper utilizes a machine learning technique called Geometric Deep Learning (GDL) to aid designers with challenging, graph-centric design problems. The strategy presented here is to take the graph data and apply GDL to seek the best realizable performing solution effectively and efficiently with lower computational costs. This case study used here is the synthesis of analog electrical circuits that attempt to match a specific frequency response within a particular frequency range. Previous studies utilized an enumeration technique to generate 43,249 unique undirected graphs presenting valid potential circuits. Unfortunately, determining the sizing and performance of many circuits can be too expensive. To reduce computational costs with a quantified trade-off in accuracy, the fraction of the circuit graphs and their performance are used as input data to a classification-focused GDL model. Then, the GDL model can be used to predict the remainder cheaply, thus, aiding decision-makers in the search for the best graph solutions. The results discussed in this paper show that additional graph-based features are useful, favorable total set classification accuracy of 80% in using only 10% of the graphs, and iteratively built GDL models can further subdivide the graphs into targeted groups with medians significantly closer to the best and containing 88.2 of the top 100 best-performing graphs on average using 25% of the graphs. [ABSTRACT FROM AUTHOR]

This paper proposes a method for estimation of tanδ of cellulosic parts in oil-paper insulation from frequency domain spectroscopy based on equivalent circuit model of oil-paper insulation in real-life transformers. Existing literature shows that overall condition of oil-paper insulation in transformer can be assessed by conventional frequency domain spectroscopy. Also, the condition of oil can be separately and easily predicted through analyzing its dielectric properties by taking out the oil samples from transformer. However, it is quite difficult to assess the dielectric properties of cellulosic parts in oil-paper insulation as it cannot be directly accessed from outside for an operating transformer. Considering the aforesaid fact, this paper presents a segregated equivalent circuit model of composite oil-paper insulation that can separately estimate the tanδ profiles for oil as well as cellulosic parts. The tanδ profiles of cellulosic parts obtained from the equivalent circuit model have been validated experimentally. Results show that the tan? profile obtained from experimental result holds good agreement with that of the proposed model. [ABSTRACT FROM PUBLISHER]

This paper presents interactive liquid crystal fiber arrays that can actuate in a way perceptible by human touch. The fibers are actuated via a computer interface, enabling precise control over actuation direction, magnitude, and frequency. Unlike conventional methods, our technique initiates the actuation at the base of the fibers, which is enabled by fabricating the fibers directly onto an electrical circuit. Fiber actuation is achieved by localized addressing of an in situ formed radially aligned segment. This induces reduction in the scalar order parameter and leads to deformation of the fiber base, causing bending toward the activated region. Extensive modeling validates this actuation mechanism and identifies optimal conditions and actuation strategies for achieving the desired responses. The actuation process is rapid, is highly reversible, and maintains excellent performance over repeated (>200) cycles. These liquid crystal fiber arrays provide a safe contact with humans or other objects, making them highly suitable for applications in smart wearable devices and immersive interfaces. [ABSTRACT FROM AUTHOR]

Many students who enroll in a first course in linear algebra major in STEM disciplines other than mathematics. Teachers who serve such students may find it difficult to provide authentic problems from these broader areas that ignite students' interest in linear algebra. In this paper, we highlight an interdisciplinary learning activity that engages students in using linear systems of equations to model the behavior of practical electric circuits. This exercise fits nicely into standard introductory linear algebra curricula and is designed to excite students majoring in engineering, physics, or applied mathematics. We also include references to a collection of open-access resources to support instructors who want to use this material in project-based, flipped-learning, inquiry-oriented, or independent-study environments. [ABSTRACT FROM AUTHOR]

Summary: This paper compares four modulation strategies applied to five‐phase voltage source inverters (5PH‐VSI). The modulation strategies under investigation are sine wave pulse width modulation (S‐PWM), fifth‐harmonic injection PWM (FH‐PWM), space vector‐PWM using two large vectors (2V‐SVPWM), and space vector‐PWM using two medium and two large vectors (4V‐SVPWM). The study utilizes simulations to analyze the results based on four performance criteria: low‐order harmonics (LOH), maximum modulation index (MMI), common mode voltage (CMV), and total harmonic distortion (THD) under balanced and unbalanced load. To validate the simulation results for these criteria, an experimental test‐bench is employed, which includes a 5PH‐VSI feeding an R‐L load, and controlled by a low‐cost STM32F4‐DISCOVERY microcontroller board. Additionally, a mathematical approach is used to calculate the total thermal losses (TTL) then simulations are performed using Piecewise Linear Electrical Circuit Simulation (PLECS) software to assess the modulation schemes based on additional thermal performance criteria: conduction losses (CL), switching losses (SL), TTL, the efficiency, and the maximum permissible heat sink thermal resistance (MPHTR) at the steady‐state regime. The results indicate that the 4V‐SVPWM method demonstrates superior efficiency in terms of THD. Furthermore, it showcases the lowest TTL at high switching frequencies, allowing for the best efficiency and minimizing MPHRT, therefore providing the largest margin for the heat sink thermal resistance design. On the other hand, the 2V‐SVPWM offers the highest MMI, but this comes at the cost of high TTL and some LOHs appearing. In addition, it exhibits the highest CMV for unbalanced load. S‐PWM and FH‐PWM offer the advantage of simpler implementation. [ABSTRACT FROM AUTHOR]

Summary In this paper, computational analysis of a Caputo fractional variable‐order system with inductor‐capacitor (LC) and resistor‐capacitor (RC) electrical circuit models is presented. The existence and uniqueness of solutions to the given problem are determined using Schaefer's fixed point theorem and the Banach contraction principle, respectively. The proposed problem's computational consequences are addressed and analyzed using modified Euler and Runge–Kutta fourth‐order techniques. Furthermore, the suggested model compares several orders, including integer, fractional, and variable orders. To demonstrate the utility of the proposed approach, computational simulations are carried out on LC and RC circuit models of various orders. Furthermore, a comparative analysis with previous investigations has been carried. For the given problem, the numerical solution results in high‐precision approximations. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model derived from an equivalent electrical circuit to describe the dynamic behavior of the high-voltage terminal of a tandem Van de Graaff accelerator. Two approaches are presented for modeling the transit time of the current flowing through the corona needles. The first one considers an equivalent self-inductance in the corona triode, whereas, in the second one, the transit time is represented by a delay in the corona current. The validation of the proposed models was carried out through experimental tests developed at the National Nuclear Research Institute of Mexico. Furthermore, two strategies for controlling the slow variations of the terminal voltage limited by the slow response of the control loop based on corona discharge are evaluated: a Proportional–Integral–Derivative controller and a sliding mode controller. The Root-Mean-Squared Error calculation leads to the conclusion that both control strategies are suitable for regulating the voltage at the accelerator potential terminal. However, the sliding mode controller leads to an overshoot-free response and a shorter settling time. [ABSTRACT FROM AUTHOR]

This paper describes a method for fabricating microfluidic electronics with 3D interconnected networks by direct ink writing (DIW)‐based 3D printing. Existing 3D printing technologies have yet to simultaneously realize 1) direct printing of interconnected multilayered microchannels without supporting materials or post‐processing and 2) integration of electronic elements with microchannels during the process of printing. This research aims to develop a method to fabricate support‐free microchannels consisting of silicone sealant without the collapse of the extruded structure while integrating electronic elements during the fabrication by DIW. The injection of liquid metal into 3D‐printed microchannels allows the formation of electrical connections between 3D conductive networks and the embedded electronic elements, enabling the fabrication of flexible and stretchable liquid metal antenna coils. To demonstrate a practical application, 1) a skin‐attachable radio‐frequency identification (RFID) tag using a commercial skin‐adhesive plaster as a substrate and 2) free‐standing flexible wireless light‐emitting devices with a small footprint (21.4 mm × 15 mm) for potential implantable applications are produced. This technology will offer a new capability to realize the automated fabrication of stretchable printed circuits with 3D configuration of electrical circuits consisting of liquid metals. [ABSTRACT FROM AUTHOR]

Engaging and understanding student-thinking in electrical circuit design can be challenging. While the analysis of circuits is an important component of an Analog Electronics course, one of the primary areas of difficulty faced by students is that they do not have a clear understanding of the current flow. Attempts at mediating this gap are usually limited to the use of metaphors and (too) much is left to the learners' imagination. This paper reports an intervention co-designed with a lecturer with regard to an undergraduate module on Analog Electronics. The intervention was an open-source immersive virtual environment designed to afford representations of learner intuitions in electrical circuit design with a view to helping their tutor have a better understanding of the roots of their misconceptions. The paper highlights some of the benefits and challenges of using immersive environments and the design and development process, as well as the collaborative learning that resulted. [ABSTRACT FROM AUTHOR]

This paper presents a simulation model for a system equipped with thermoelectric elements, considering the impact of independent thermal contact resistances on each side of the module. An analytical model was constructed, taking into account the asymmetry of thermal resistances between the generator/cooler and the respective heat source/heat sink. A comparative analysis of thermoelectric device operating indicators such as conducted heat, efficiency, and the electricity/cooling power produced was performed. The selection of electrical current in the circuit was analysed based on the maximization of power or efficiency. This paper discusses deviations from ideal conditions, specifically the absence of thermal resistance between the heat source/sink and the thermoelectric junction. The model accurately simulates the operating conditions of the thermoelectric system with a low computational cost. The results indicate that the total thermal resistance, rather than its location, predominantly affects the operation of the thermoelectric generator. However, in cooling operations, the influence of thermal resistance significantly depends on the cooling power demand and temperature. [ABSTRACT FROM AUTHOR]

The paper presents new diagnostic method applied to assess aging degree for paper-oil insulation used in professional electrical power device, primarily including medium and high power transformers. The described method is based on modified diagnostics using the recovery voltage effect occurring in dielectrics (RVM ? Recovery Voltage Methods). Modification of the RVM method applied so far, which is now used only to assess moistening degree for paper-oil insulation in power transformers, consists in a new parametric analysis of recovery voltage time characteristics. Simulation and experimental tests carried out in laboratory conditions for adequately prepared insulation samples have proven that the time-constant of recovery voltage decay (?R_MIN) is the most susceptible parameter as regards quantitative change in the function of aging of the examined insulation. This conclusion is also confirmed by statistical studies, in which a multi-parameter variance analysis method has been applied. An original equivalent circuit diagram of the insulation has been used to simulate aging degree of paper-oil insulation samples in numerical tests. The diagram is based on the Cole-Cole type dielectric response model. [ABSTRACT FROM AUTHOR]

Herein, we proposed the addition of an inkjet-printed conductive pattern to paper-based analytical devices (PADs) in order to expand their applications. An electric conductive pattern was easily, quickly, and inexpensively fabricated using a commercial inkjet printer. The addition of a printed electric element will enhance the applications of PADs without the loss of properties such as cost efficiency, disposability, and portability. In this study, we applied an inkjet-printed heater to a piece of paper and investigated its characteristics. The use of the heater as a valve, concentrator, and heat source for chemical reactions on PADs was investigated. Previously, these functions were difficult to realize with PADs. The inkjet-printed heater was used as a valve and concentrator through evaporation of the working fluid and solvent, and was also found to be useful for providing heat for chemical reactions. Thus, the combination of printed electric circuits and PADs has many potential applications. [ABSTRACT FROM AUTHOR]

Compared to conventional ac cables, the current rating of HVDC cable circuits is more complicated because the permissible current is not only limited by the operating temperature, but also by the electrical stress within the insulation. Therefore the IEC60287 current rating standard is considered insufficient for some HVDC applications because it fails to include the stress limitation. This paper presents an analytical methodology to calculate an electrical stress-limited rating for HVDC cables, which considers the maximum dielectric stress as the current limiting factor. This paper represents the first part of a project which has comprehensively reviewed cable rating calculations for mass impregnated HVDC cable systems. [ABSTRACT FROM PUBLISHER]

Samples of a dried composite oil-paper system were thermally aged in the laboratory under N2 in a sealed container and analysed using their dielectric response. The contributing loss processes were separated using an equivalent circuit model containing constant high frequency capacitances, dc-conductances, a dispersive capacitance, and a low frequency quasi-dc (q-dc) dispersion process as circuit elements. This low frequency dispersion in oil-paper samples is a bulk property of the system that is often mistaken for a dc conduction process when only the imaginary capacitance or ac-conductance is measured. The Dissado-Hill response function is proposed for the frequency dependence of the dispersive capacitance in the mid-frequency range rather than the Debye function because its cluster concepts correlate with the sample morphology of a matrix of oil-filled cavities. The quasi-dc dispersion is assigned to the transport of mobile charges between charge-clusters associated with locally connected oil filled cavities, which is a process that can be represented on a global scale by the form of hierarchical circuit system that leads to constant phase angle responses, and is here modelled by the Dissado-Hill q-dc function. It was found that the two dispersions moved together to higher frequency with thermal ageing of the composite material. The characteristic frequency common to the dispersions had an activation energy that decreased with thermal ageing, whereas their amplitude increased. This behavior is discussed in terms of possible changes to the oil-paper composite caused by the ageing process. [ABSTRACT FROM AUTHOR]

This study investigates the application of a Wheatstone bridge, specifically through the utilization of a meter bridge constructed on chart paper using pencil graphite. Employing the Wheatstone bridge principle, this study aims to achieve precise measurements of an unknown resistance. Results indicate an error margin between measured and calculated values of less than 10%, highlighting the efficiency and accuracy of this approach. The demonstrated effectiveness of the meter bridge serves as an educational resource, particularly beneficial for K-12 students, providing practical understanding and hands-on experience with the meter bridge concept. This research contributes to enhancing STEAM education by offering a tangible and accessible tool for teaching electrical circuit principles. [ABSTRACT FROM AUTHOR]

We demonstrate a novel method for controlling fluid flow in paper-based devices. The method delays fluid progress through a porous channel by diverting fluid into an absorbent pad-based shunt placed into contact with the channel. Parameters to control the delay include the length and the thickness of the shunt. Using this method, reproducible delays ranging from 3 to 20 min were achieved. A simple electrical circuit model was presented and used to predict the delays in a system. Results from the model showed good agreement with experimental observations. Finally, the shunts were used for the sequential delivery of fluids to a detection zone in a point-of-care compatible folding card device using biochemical reagents for the amplified detection of the malaria protein PfHRP2. [ABSTRACT FROM AUTHOR]

Summary The aim of this paper is to present a methodology for solving а dynamic electric circuit with nonlinear hysteretic inductor without the use of hysteresis model or equivalent circuits. A consideration of nonlinear and hysteretic behaviour of the magnetic core under quasistatic conditions is based on applying harmonics interpolation method (HIM) to the measured magnetising field strength waveforms. A dynamic behaviour of the magnetic core is considered through the application of the statistical theory of losses (STL). A considered electric circuit consists of AC voltage source connected in series with shunt resistor, additional linear resistor and inductor, as well as a nonlinear hysteretic inductor. The solution for electric current of the circuit is obtained by solving equation derived from Kirchhoff's laws through a series of successive iterations. Coupling of electric and magnetic part of the circuit is obtained from fundamental laws of electromagnetism. Methodology is validated for four cases of the considered electric circuit — without additional elements, with one additional or both additional elements, for sinusoidal voltage source amplitudes of 2, 4, 6, 8 and 9 V and frequency of 50 Hz. Validation is repeated for frequencies of 100, 200 and 300 Hz while keeping the ratio of the amplitude to frequency constant. Detailed theoretical approach and methodology, comparisons between measured and calculated results, as well as adequate discussion are presented. [ABSTRACT FROM AUTHOR]

This paper presents π HyFlow, a modular approach to the process interaction worldview (PI). Traditionally, PI supports a set of interacting processes without enabling modular and hierarchical model definition. π HyFlow basic models define a dynamic set of processes while also enabling a modular interface for supporting model composition. π HyFlow allows an exact representation of continuous signals based on the concepts of dense outputs, and generalized sampling. π HyFlow ability to support accurate models of hybrid systems is presented through a DC-DC converter (DCC) based on a resistor–capacitor (RC) electrical circuit. The DCC output voltage can be modeled by a first-order differential equation that is solved using an exponential time differencing (ETD) integrator. The DCC network model uses a digital on-off controller and an ETD. Simulation results are generated by π HyFlow ++, a C++ implementation of the formalism. [ABSTRACT FROM AUTHOR]

Ground magnetic field variations have been used to investigate ionospheric dynamics for more than a century. They are usually explained in terms of an electric circuit in the ionosphere driven by an electric field, but this is insufficient to explain how magnetic field disturbances are dynamically established. Here we explain and simulate how the ionosphere dynamically responds to magnetospheric forcing and how it leads to magnetic field deformation via Faraday's law. Our approach underscores the causal relationships, treating the magnetic field and velocity as primary variables (the B, v paradigm), whereas the electric field and current are derived, in contrast to the E, j paradigm commonly used in ionospheric physics. The simulation approach presented here could be used as an alternative to existing circuit‐based numerical models of magnetosphere‐ionosphere coupling. Plain Language Summary: Ground magnetic field variations have been used to investigate ionospheric dynamics for more than a century. They are usually explained in terms of an electric circuit in the ionosphere driven by an electric field; similar to how we would explain the magnetic field of a current‐carrying wire. However, this approach oversimplifies the complex reality in space plasmas. Here, the relationship between currents and magnetic fields is reversed: currents should be understood as a consequence of the magnetic field, and not the other way around. In this paper we explain and simulate how the ionosphere dynamically responds to forcing from above, and how it leads to magnetic field deformation that corresponds to an electrical current. Key Points: We present a model and simulation of how the magnetic field in the ionosphere dynamically changes in response to external forcingOur model emphasizes the causal relationships, treating B and v as primary instead of E and j, as is commonly done in ionospheric physicsSimulation results highlighting the self‐consistent ionospheric response in the B, v paradigm are presented [ABSTRACT FROM AUTHOR]

There are important challenges in modeling large electrical distribution circuits, especially with the presence of distributed renewable generation. Constructing simulations to assess the effect of the penetration of distributed generation on electrical distribution networks has become of great importance for Distribution Network Operators (DNOs). This paper proposes a simulation strategy based on open-source platforms and the integration of scripting tools for the rapid modeling of large-scale electrical distribution circuits with distributed renewable generation. The implementation is based on the adaptation of a tool called QGIS2OpenDSS, which creates OpenDSS distribution network models directly from an open-source geographic information system, QGIS. The plugin's capabilities are demonstrated using a real distribution feeder with more than 60% penetration of renewable generation based on photovoltaic systems. These simulations are carried out using real data from a circuit provided by a DNO in the Dominican Republic, which is used to demonstrate how this approach provides a more accessible and flexible way to simulate and assess the effect of Distributed Energy Resources (DERs) in medium voltage (MV) and low voltage (LV) networks, enabling utilities to evaluate system performance and identify potential issues. The integration of this open-source tool within the DNO software stack enables users to apply it according to specific project needs, enhancing their capability to analyze and manage high DER penetration levels, aiding in better planning, operation, and decision-making processes related to renewable energy projects. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy (EIS) is a modern and efficient method for the evaluation of the protective abilities of coatings. However, the interpretation of the experimental data is a difficult task. This paper aims to investigate the effect of the addition of a nano clay, Cloesite 30B®, on the barrier properties of an epoxy-based system through electrochemical impedance spectroscopy in an aerated sodium chloride solution. The EIS spectra of the samples analysed showed different evolutions over time. The subsequent processing of spectra using equivalent electrical circuits is an excellent analytical tool and allows the protective capacity of coatings to be assessed. By using this analysis, it was possible to define and comprehend the impact of adding nano clay in different concentrations to the epoxy resin coating. The work has shown the effectiveness of increasing the barrier effect of the coating with this type of nano clay. However, the improvement is linked to obtaining a correct dispersion of nanoparticles. Otherwise, there is the formation of macro-clusters of particles inside the coating. Their appearance can cause a deterioration in coating performance. [ABSTRACT FROM AUTHOR]

Equivalent circuit models (ECMs) are widely used to assess the photoconductive antennas (PCAs) performances in terahertz (THz) systems. However, an existing version, which has been vastly used as a reference in recent works, exhibits some inconsistencies. In this paper, we have investigated its physical behavior according to the antenna theory. Besides, we have demonstrated that the circuit element expressions are not accurate and can have an impact on the PCA evaluation based on this model. Moreover, we have illustrated that the direct deduction of antenna parameters (exciting current and radiated voltage) from the electrical circuit is not in line with the antenna theory. Then, a straightforward model for an accurate THz photoconductive antenna evaluation that is simple, clear, and without ambiguities, has been developed. The proposed ECM design models the physical phenomena in the PCA with direct lumped elements to make the interpretation easier. Additionally, an innovative direct relationship between the space charge screening voltage and the gap voltage has been demonstrated. Consequently, the developed differential equation for time-dependent gap voltage is simple to apply, and other circuit parameters are determined directly without any ambiguity. Furthermore, we have evaluated the PCA performance based on the proposed model. Finally, the proposed model results accuracy has been examined with comparison versus measurement results obtained from the analyzed model. Our proposed model provides a good agreement with experimental measurements, demonstrating its accuracy and effectiveness in assessing photoconductive antenna performances. Our findings contribute efficiently to the improvement of a more precise and reliable model for THz photoconductive antenna evaluation, presenting a valuable and simple model for future PCA designs and assessments. [ABSTRACT FROM AUTHOR]

In this paper, the sequential conformable Langevin-type differential equation is studied. A representation of a solution consisting of the newly defined conformable bivariate Mittag-Leffler function to its nonhomogeneous and linear version is obtained via the conformable Laplace transforms' technique. Also, existence and uniqueness of a global solution to its nonlinear version are obtained. The existence and uniqueness of solutions are shown with respect to the weighted norm defined in compliance with (conformable) exponential function. The concept of the Ulam–Hyers stability of solutions is debated based on the fixed-point approach. The LRC electrical circuits are presented as an application to the described system. Simulated and numerical instances are offered to instantiate our abstract findings. [ABSTRACT FROM AUTHOR]

The integration of water electrolysis with renewable energy sources (RESs) constitutes a milestone in the transition to neutral and sustainable energy systems. The attractive features of the Proton Exchange Membrane (PEM) electrolyzer such as high purity of hydrogen, operation with high pressure, and high current densities have made it a critical technology to produce green hydrogen from RESs. Accurate models are required for proper design, analysis, and control of the electrolyzer when connected to the grid or renewable energy systems. Amongst the various types of models proposed for modeling the PEM electrolyzer, electrical circuit models are the easiest, most appealing, and straightforward to use for the investigation of electrolyzer operation and control. This paper presents an exhaustive review of the electrical circuit modeling reported in the literature on PEM electrolyzers. The reviewed models are classified analogously to the classifications of physical modeling in terms of voltage components (reversible, ohmic, activation, and concentration voltage drop), model behavior (static/dynamic), and modeling scale (cell/stack). Furthermore, MATLAB simulations of the reviewed models are implemented and the results are compared to pinpoint their similarities and deviations. Moreover, the applications, challenges, benefits, and drawbacks of the electrolyzer's electrical equivalent circuit modeling are discussed and overarching recommendations are set out for further research on the PEM electrolyzer modeling. The paper can be used as a comprehensive reference for choosing the appropriate electrical model of the electrolyzer for beginners as well as for research and industry experts who rely on PEM electrolyzer models in their work. • A comprehensive review of the electrical circuit models of the PEM electrolyzer is presented. • The models are classified in terms of voltage components, model behavior, and scale. • Simulations of the models are implemented to show their similarities and deviations. • Applications, benefits, and drawbacks of electrical circuit modeling are discussed. • Overarching technical recommendations are drawn for further research on electrical circuit modeling. [ABSTRACT FROM AUTHOR]

Battery state estimation is fundamental to battery management systems (BMSs). An accurate model is needed to describe the dynamic behavior of the battery to evaluate the fundamental quantities, such as the state of charge (SOC) or the state of health (SOH). This paper presents an overview of the most commonly used battery models, the equivalent electrical circuits, and data-driven ones, discussing the importance of battery modeling and the various approaches used to model lithium batteries. In particular, it provides a detailed analysis of the electrical circuit models commonly used for lithium batteries, including equivalent circuit and thermal models. Furthermore, a comprehensive overview of data-driven approaches is presented. The advantages and limitations of each type of model are discussed. Finally, the paper concludes with a discussion of current research trends and future directions in the field of battery modeling. [ABSTRACT FROM AUTHOR]

With the aim of preparing paper-based writing electronics, a kind of conductive pen was made with nano-silver ink as the conductive component and a rollerball pen as the writing implement. This was used to direct-write conductive patterns on Epson photo paper. In order to decrease the sintering temperature, pressure was introduced to enhance the driving forces for sintering. Compared with hot sintering without pressure, hot-pressure can effectively improve the conductivity of silver coatings, reduce the sintering time and thus improve productivity. Importantly, pressure can achieve a more uniform and denser microstructure, which increases the connection strength of the silver coating. At the optimum hot-pressure condition (sintering temperature 120 °C/sintering pressure 25 MPa/sintering time 15 min), a typical measured resistivity value was 1.43 × 10-7 Ω m, nine greater than that of bulk silver. This heat treatment process is compatible with paper and does not cause any damage to the paper substrates. Even after several thousand bending cycles, the resistivity values of writing tracks by hot-pressure sintering stay almost the same (from 1.43 × 10-7 to 1.57 × 10-7 Ω m). The stability and flexibility of the writing circuits are good, which demonstrates the promising future of writing electronics. [ABSTRACT FROM AUTHOR]

This research paper presents a symmetrical current-tunable active-RC all-pass filter that uses an active BJT coupled with R and C. The circuit's symmetrical structure ensures that the differential signals are treated equally, resulting in improved performance. Furthermore, the filter's ability to adjust the frequency by bias current makes it suitable for a wide range of applications, such as improving phase properties and creating other types of filters. The simulation results obtained through the Pspice program show that the value of the operating frequency can be adjusted by bias current, which is the highlight of this research. The transfer function of the circuit shows a response of about 0 dB and -90° respectively, indicating that the circuit can change the phase of the input signal without changing its magnitude. This feature is particularly useful in signal processing applications where phase changes are required. In addition, the paper discusses how the operating frequency can be increased by decreasing the capacitor. The transfer function of the circuit analyzed shows that the operating frequency (f0) is inversely proportional to the product of the capacitors. Therefore, decreasing the value of C increases the operating frequency of the circuit. Monte Carlo analysis results are also presented for resistors, capacitors, and transistors with error values. This analysis helps determine the effect of errors on the output signal of the circuit. The results show that the output signal is sensitive to changes in the resistor values, which can affect the accuracy of the filter. Therefore, it is important to select high-quality resistors to ensure that the filter operates accurately. [ABSTRACT FROM AUTHOR]

This paper presents three pieces that use objects, or object types, to reveal the material, personal, institutional and commercial networks that surrounded the introduction and successful use of instruments, systems and techniques. The objects explored are: the Hourly Signal Relay, used within the time signal system of the Royal Observatory, Greenwich, from the mid-nineteenth century; photographic glass plates from the British 1874 transit of Venus expeditions; and an electronic imaging tube, Lallemand's camera, developed in Paris and used at the Lick Observatory in California in the 1960s. Each story uses examples of failure as a means of highlighting a lack of robustness in or effort required to maintain these networks. Once created, however, such networks could, as the second two stories note, go on to develop and support alternative approaches, helping to create success from apparent failure. Nevertheless, complexity, failure and fragility have also led to the underrepresentation or obscurity of these objects in museum collections, until given focused attention in these studies. The paper forms part of a collection of articles: Revealing observatory networks through object stories. The other papers in the collection are 'Object itineraries', and 'Observatory audiences' and the genesis of the collection is discussed in the 'Introduction'. [ABSTRACT FROM AUTHOR]

Periodic structures have gained attention in the research community since they show attenuation zones in their frequency response, called bandgaps. In this paper, the interactions of two mechanisms of bandgap formation in mono-coupled periodic structures are examined, i.e., Bragg scattering and local resonators. With reference to longitudinal elastic waves, an analytical study is carried out to describe in detail the formation of bandgaps. Local resonators are implemented via piezoelectric inserts shunted with a resonating electrical circuit for which a non-traditional model is needed since the study concerns higher frequencies with respect to those of the subwavelength regime. Design maps and tuning formulas are developed not only for the case of infinite structures, but also for the finite case, highlighting the role of the number of unit cells and that of resonances in the attenuation zones. Among the possible tuning strategies of local resonators, it is shown that the mutual influence between elastic and electric parameters is able to produce a wider attenuation zone, bridging Bragg scattering bandgaps thanks to the effect of local resonators. The analytical findings of this paper are validated with numerical results in an example application. [ABSTRACT FROM AUTHOR]

This paper concerns the effects of electrodynamic forces that act on current paths that are part of high-grade industrial distribution switchgear. This work is composed of experimental and simulation sections. In the experimental section, the short-circuit tests are presented and the occurrence of electrodynamic forces are shown in a visible way. The formation of electrodynamic forces in the current circuits of electrical energy distribution systems is related to the flow of high currents, but mostly it is related to short-circuit currents. In order to highlight these phenomena, the detailed specification of the parameters during tests is displayed. In the simulation section, the physical phenomenon of electrodynamic forces is being captured by employing a detailed real-scale model of switchgear and current paths. Therefore, the authors proposed employment of the FEM (finite element method) in order to obtain values of electrodynamic forces acting on the current paths by executing the detailed 3D coupled simulation. The analysis of the results and aftermath effects of their interactions provided interesting conclusions that concerned the operation of such power distribution layouts in critical short-circuit conditions. [ABSTRACT FROM AUTHOR]

This paper proposed modeling, designing and battery management system for a three-wheeled electric vehicle for the Indian road under different conditions. The system consists of a lithium nickel manganese cobalt oxide cell-based lithium-ion battery with a managing system known as battery management system (BMS) described here. The process for modeling the vehicle, choosing the motor, developing the controller with a programmable circuit and developing the DC–DC buck converter, and battery pack of the lithium-ion cell with an effective BMS is discussed. According to the study, a prototype programmable controller circuit board, including the PWM-controlled driver circuit, is built for the proper flow of electricity on urban roads in India and has been tested successfully on road. This developed electric prototype travels the range of 100 km with an average speed of 32 km/h, while the maximum current drawn from the battery is 30_amp. The efficiency increased by 2% compared to the market-available PWM square wave controller. MATLAB simulation is done to compare the effectiveness of the modeled system with the suggested prototype control system. To verify the system, a small-scale prototype is developed. [ABSTRACT FROM AUTHOR]

In this paper, the new generalized stochastic fractional potential-KdV model is investigated analytically which describes the nonlinear optical solitons and photons propagating in electric circuits and multicomponent plasmas. The governing model is transformed into a bilinear form using the Hirota bilinear method. A variety of novel waves structures are developed in the form of lump waves, collisions between lump waves and periodic waves, collisions between lump waves or single and double-kink soliton solutions, collisions between lump, periodic, single and double-kink soliton solutions. Furthermore, the ( G ′ / G 2 ) expansion method and the Adomian decomposition method are employed to construct a number of new configurations for the governing dynamical model. To validate the scientific computations, a comparison study and stability analysis are carried out efficiently. Finally, to understand the dynamical behaviour of the the nonlinear fractional model, the 3D, 2D, and contour plots have also been demonstrated with the appropriate set of parameters. Depending upon the efficiency and the validity of the applied techniques, it is established that these strategies can also be applicable to many contemporary models. [ABSTRACT FROM AUTHOR]

2R-1C equivalent circuit is widely used in electrochemical impedance spectroscopy (EIS), such as modelling of lithium-ion batteries, bioimpedance analysis and water quality monitoring. It allows for an analysis of the basic electrical behavior of electrochemical systems and understanding of the underlying principles. However, the reported parameter estimation methods are usually deployed on the PC-based processing units that limit in-situ and unsupervised applications, where estimation results are free from user inputs. This paper presents a novel methodology for extracting the values of 2R-1C equivalent circuit by solely utilizing the measured impedance modulus. Unlike iterative and PC-based estimation methods, this approach eliminates user inputs in terms of a need for an initial guess, addressing a significant drawback of those approaches. The proposed work was validated by simulated and experimentally obtained impedance. Moreover, details of deployment on the PC-based and embedded hardware were also reported. The utilization of embedded hardware platform (Mega2560) enables an efficient processing of EIS data (80 milliseconds for 100 datapoints) by creating opportunities for in-situ parameter extraction of equivalent electrical circuits. [ABSTRACT FROM AUTHOR]

Summary: To accurately and efficiently calculate the frequency response of the lumped parameter equivalent circuit model (LPECM) of a transformer winding is the basis for studying the simulation method of the frequency response analysis (FRA). In this paper, two different cut‐set matrix (CSM) methods, including fundamental cut‐set (FCS) and independent cut‐set (ICS) matrix methods, are proposed to calculate the FRA curves of the LPECM of a three‐winding power transformer. First, based on graph theory and electrical circuit laws, the basic CSM equation is deduced. Second, four different FCS matrix selection methods of the LPECM are introduced and the best FCS matrix is determined by deeply analyzing their characteristics. Then, an ICS matrix method is proposed to obtain the ICS of the LPECM. Furthermore, FCS and ICS are taken into the CSM equation to calculate the FRA results of the LPECM, respectively. Finally, the accuracy of the proposed methods is validated by Multisim software and the performance of these two methods is compared with node voltage matrix (NVM) method by analyzing the calculation time. The results show that FCS and ICS matrix methods both can be used to accurately obtain the FRA results of the LPECM of the three‐winding power transformer, but ICS is more simple than FCS matrix method due to avoiding the procedure for the selection of the tree. In addition, since ICS matrix method has the shortest running time among these methods, it can be used to improve the calculation efficiency of the FRA curves of the LPECM of a three‐winding power transformer. [ABSTRACT FROM AUTHOR]

The soft set theory proposed by D. Molodtsov in 1999 is a general mathematical method for dealing with uncertain data. Now many researchers are applying soft set theory in decision making problems. Graph theory is the mathematical study of objects and their pairwise relationships, known as vertices and edges, respectively. The concept of soft graphs is used to provide a parameterized point of view for graphs. Directed graphs can be used to analyze and resolve problems with electrical circuits, project timelines, shortest routes, social links and many other issues. We introduced the notion of the soft directed graph by applying the concepts of soft set in a directed graph. In this paper, we introduce the concept of soft subdigraph and some soft directed graph operations like AND operation, OR operation, soft union, extended union, extended intersection, restricted union and restricted intersection and investigate some of their properties. [ABSTRACT FROM AUTHOR]

Since a motor drive system contains an inverter (high‐voltage circuit) and gate drive circuits (low‐voltage circit) with a switching regulator, electromagnetic noise is generated in each of these two circuits, and noise interference between these circuits can occur. This paper discusses noise interference between the high‐ and low‐voltage circuits of an electric compressor system with an integrated mechanical and electrical structure. Analysis using LTspice shows that the experimental and analytical results are in good agreement when a very small stray capacitance occurs between the high‐ and low‐voltage circuits. An experiment using an actual compressor showed that conducted noise above 20 MHz can be reduced by up to 10 dB by reducing the effect of stray capacitance between these circuits. [ABSTRACT FROM AUTHOR]

A model expressing beams, pillars, and electrical wiring in a building for lightning surge simulation by circuit analysis method is proposed in this paper. The proposed model expresses the self‐surge impedance of the electrical wiring as a function of the distance between conductors and the radius of the electrical wiring. The mutual impedance is expressed by the distance between the surfaces of a structure and a nearby wire instead of the distance between the conductor centers. In the case of two conductors having far different radii in proximity, the distribution of electromagnetic fields around the two conductors is similar in horizontal and vertical arrangements. Thus, the electrical wiring nearby pillars can be treated as a horizontal conductor. The circuit analysis results show that the voltage difference generated between the structure and the electrical wiring is calculated more precisely by the proposed model than by the conventional model. [ABSTRACT FROM AUTHOR]

Solar Photovoltaic (SPV) technology advancements are primarily aimed at decarbonizing and enhancing the resiliency of the energy grid. Incorporating SPV is one of the ways to achieve the goal of energy efficiency. Because of the nonlinearity, modeling of SPV is a very difficult process. Identification of variables in a lumped electric circuit model is required for accurate modeling of the SPV system. This paper presents a new state-of-the-art control technique based on human artefacts dubbed Drone Squadron Optimization for estimating 15 parameters of a three-diode equivalent model solar PV system. The suggested method simulates a nonlinear relationship between the P–V and I–V performance curves, lowering the difference between experimental and calculated data. To evaluate the adaptive performance in every climatic state, two different test cases with commercial PV cells, RTC France and photo watt-201, are used. The proposed method provides a more accurate parameter estimate. To validate the recommended approach's performance, the data are compared to the results of the most recent and powerful methodologies in the literature. For the RTC and PWP Photo Watt Cell, the DSO technique has the lowest Root Mean Square Error (RMSE) of 6.7776 × 10–4 and 0.002310324 × 10–4, respectively. [ABSTRACT FROM AUTHOR]