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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]

Cooking from ancient times has evolved from using open fires to wood, gas cookers, using liquefied petroleum gas (LPG). This has also come with various adverse effects ranging from gas leakages to burnt food due to absent-mindedness, thereby creating a significant disaster that could lead to loss of life and property damage. The study aimed to reduce the rate of liquefied petroleum gas related accidents in domestic usage and improve the safety of domestic gas users. An automated method to enforce safety was proposed to avoid unwanted cooking gas flow consequences, especially in homes. The paper presents a control system using an Arduino Uno with a control design interfaced with a utensil sensor, solenoid valve, and a timer circuit to allow gas flow to commence and ignite a flame automatically. The automatic ignition apparatus, which has a high-voltage electric circuit, begins to function once the utensil detector comes in contact with silverware. The system is designed to function in different modes to ensure safety and prevent gas flow. The prototype serves as a means of curbing gas wastage and increasing the safety of people who use LPG as a source of fuel for cooking. [ABSTRACT FROM AUTHOR]

This paper proposes a systematic method for the identification of the load circuit parameters (say the $\boldsymbol{R}$ , $\boldsymbol{L}$ , and $\boldsymbol{C}$ elements) based only on the information of the instantaneous voltage and current measured at the point of common coupling (pcc). Geometric Algebra (GA) and concepts of differential geometry are used to produce a rigorous mathematical framework. The identification is formulated as a multidimensional geometrical problem that is solved conveniently by means of GA. Once the passive elements of the load have been identified, the active and reactive powers can be computed from first electromagnetic principles (Maxwell Equations). The theory is general and is verified with linear and nonlinear circuits. The paper shows single-phase circuits but the theory can be extended to three-phase circuits. The method is easy to program and has shown to be very robust for all tested cases. Because of its generality, the method presented will find applications beyond electric circuits. [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]

The papers in this special section were taked from the analog, data converter, RF, wireless, and wireline communications sessions at the IEEE International Solid-State Circuits Conference (ISSCC) in San Francisco, CA, in February 2015. [ABSTRACT FROM PUBLISHER]

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]

This paper provides a comprehensive review of various error compensation techniques for fixed-width multiplier design along with its applications. In this paper, we have studied different error compensation circuits and their complexities in the fixed-width multipliers. Further, we present the experimental results of error metrics, including normalized maximum absolute error , normalized mean error and normalized mean-square error to evaluate the accuracy of fixed-width multipliers. This survey is intended to serve as a suitable guideline and reference for future work in fixed-width multiplier design and its related research. [ABSTRACT FROM AUTHOR]

This paper focuses on the module "Fundamentals of Electrical Engineering," in which students from different engineering disciplines often face difficulties. Despite efforts to enhance the course through digital media, the formation of study groups, and adjusted lecture and exercise materials, there is still a high failure rate in the subject, leading to potential student dropouts. The primary goal is to analyze students' challenges in solving electrical engineering problems to evaluate their grasp of the fundamentals of electrical engineering and identify varying levels of competence. The findings are based on a cross-sectional study conducted at the conclusion of a university course in Germany, involving 196 students. Through item response theory (IRT) analyses, it was determined that the assessment items demonstrated satisfactory fit values. The proficiency model delineates four levels, with only 8.2% of students achieving the highest level. At this stage, students can tackle more intricate problems using circuit analysis techniques. However, a notable portion of students (40.3%) lack a basic understanding of electrical circuits, placing them at the lowest level. [ABSTRACT FROM AUTHOR]

This paper introduces Education Platform for Equivalent Resistance (EDUPERES) and Gamification of Equivalent Resistance (GAMERES), two different parts of a new computer aided education platform with interactive and imaginative design and game elements, which have been created during 4 years. In Vocational School of Transportation of Eskişehir Technical University, electrical circuit analysis is a compact course which exhaustively yet quickly covers all the DC and AC circuit concepts. During the course, it is observed that some students have difficulties in some basic capabilities such as calculation of equivalent resistance of either a standard or a compact circuit, dividing currents, and so on. More sadly, this inability spreads to the rest of the semester. This study aims to overcome this issue through a smart interactive education platform and gamification. The first part, that is, EDUPERES visualizes and animates the solutions of electrical circuits. To make the students exercise circuit questions, it provides an interface which simulates the comfort of using paper and pencil. This platform is powered by a smart algorithm to watch almost all of the actions of the students and to give prompt warnings. It allows students to transform the shapes of compact circuits during circuit reduction. The second part, that is, GAMERES imaginatively converts the circuit questions into action, competition, shooter, puzzle, and maze games. Via box plots and Mann–Whitney–Wilcoxon nonparametric tests, it is shown that EDUPERES and GAMERES can significantly increase students' learning. The success of EDUPERES and GAMERES is discussed with regard to previous studies and gamers' motivations. [ABSTRACT FROM AUTHOR]

Impedance Spectroscopy (IS) is a general term for the technique referring to small-signal measurements of the linear electrical response of a domain of interest. This method is based on the analysis of the system's electrical response to yield helpful information about its domain-dependent physicochemical properties (generally, the analysis is carried out in the frequency domain). Nowadays, there are many areas of application where IS can be used to evaluate or enhance the development of emerging products and processes. As a contribution to this field of research, this paper presents relevant theoretical–practical aspects of the interpretation and analysis of the electrical behavior of materials based on IS and IS modelling. The work starts by historically introducing IS and then goes through different domains of application of the technique, such as Materials Science and correlated areas. Afterwards, an introduction to IS usage for constructing equivalent electrical circuits is presented, aiming at modelling the materials' electrical behavior, followed by examples from the literature that use the two possible circuit development approaches, the series and the parallel association of circuit elements. Lastly, the authors present a case study of their most recent efforts of a circuit model development of relative humidity (RH) sensors based on heterogeneous mixed metal oxide (MMO) nanostructures, used to understand and identify existing contributions to the overall electrical response of the sensors to moisture; in their case, the electrical response of the MMO sensors was modelled with a high level of superposition between the experimental and fitted data, using a parallel combination of circuit elements, which is an unconventional one. [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]

Circuit simulators are fundamentally used for solving electric circuit problems with different degrees of complexity in which node voltages and branch currents are the unknowns. This is fully understandable since they were originally created for this specific task. However, behind the curtains, powerful simulation engines based on a variety of numerical techniques operate so as to always comply with Kirchhoff's current and voltage laws. In this paper, it is shown how a simple circuital configuration, referred to as the elementary solver, consistent in two behavioral current sources in series, can be used to solve mathematical problems that go beyond electronics. Of course, the intention is not to substitute mathematical packages with well-proven calculus capacity but to increase the scope of circuit simulators for their application in other areas of research or simply for educational purposes. It is worth mentioning that no special programming skills are required (except a basic knowledge of the available tools and language) and, furthermore, that the user can operate exclusively in a graphical environment. It is shown, throughout a series of selected examples, how the method of elementary solvers (MES) works, providing a new and practical dimension to the applicability of circuit simulators. [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]

This paper presents a comprehensive review of the design and implementation methods of low-power piezoelectric energy harvesting circuits, which in the last few years have gained an extremely large range of applications like the power sources of wearable electronic devices, such as biometrical sensors. Before examining the electronic circuitries of the self-supplied power devices, an overview of the structure, equivalent electrical circuits, and basic parameters of the piezoelectric generators and MEMSs as energy harvesting elements is presented. The structure of energy storage elements (parallel-plate capacitors and thin-film supercapacitors), suitable for this type of application, is also presented. The description of these components from an electrical point of view allows them to be easily workable when connected to the various power conversion electronic circuits. Based on an overview of the structure and the principles of operation, as well as some analytical expressions for energy efficiency evaluation, a comprehensive comparative analysis is presented. Depending on the advantages and disadvantages of the known circuit configurations, the basic electrical and design parameters are systematized in tabular form. Practical realizations of piezoelectric power conversion circuits are also presented in graphic form, ensuring the optimal value of energy efficiency and compactness in the construction of the devices. [ABSTRACT FROM AUTHOR]

Datapath synthesis is a crucial step in synthesis flow and aims at globally minimizing an area by identifying shareable logic structures. This paper introduces a novel Directed Acyclic Graph (DAG)-based datapath synthesis method based on graph isomorphism and gate reconfiguration. Unlike algorithms that identify common specification logic, our approach simplifies the problem by focusing on searching for common topology. Leveraging the concept of gate reconfiguration, our algorithm extends the applicability of DAG-based datapath synthesis by transforming a topology-equivalent network into a specification-equivalent network. Experimental results demonstrate up to 23.6% improvement when optimizing the adder–subtractor circuit, a scenario not addressed by existing DAG-based datapath synthesis algorithms. [ABSTRACT FROM AUTHOR]

Because of the large number of parameters that interact in amplifier functions, determining dynamic regime parameters as well as the mode of function of amplifier stages is an extremely complex problem. This paper describes a LabVIEW application for studying the functioning of an amplifier in various connections. The user selects the generator's parameters, the type of connection and its parameters, as well as the load circuit characteristics. The application can determine both the stage characteristics and the Bode characteristics. The amplifier's stability zone, as well as its gain and phase, are determined based on these characteristics. An important advantage of this application is that the design of the amplifier stage can be created starting from some parameters that the amplifier can establish, from which the values of components can be determined. In order to validate the simulation results from the LabVIEW application, the specialized program Multisim was used, as well as experimental measurements using the Electronics Explorer Board. Both Multisim and Electronics Explorer Board can determine Bode characteristics. In both simulations and experimental amplifiers, the same schemes with the same transistor were used. The application can be used for educational purposes as well as to design an amplifier's stage to achieve specific parameters. [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]

In this paper, we focus on the development of a machine for manufacturing needle probes used in the electrical testing of printed circuit board (PCB) in-circuit-test fixtures. Currently, the manufacturing process for needle probes involves manual tasks such as wire threading, soldering, heat shrink tubing application, heat shrink tubing heating, and placing cylindrical terminals into a needle disc. Owing to the time-consuming nature of this production process, automation is proposed for improvement. The system development involves programmable logic controller (PLC) control and pneumatic cylinder mechanisms to replicate the manual wire threading process. Pneumatic grippers are used to position cylindrical terminals and heat shrink tubing. Two stepper motors drive plastic rollers for copper wire extension by a rolling process along V-shaped groove straightening guides, reaching the wire insertion holes on the PCB. A YZ-axis servo stage with clamping fixtures secures the PCB and moves it to the wire insertion holes. Once the copper wire extends through the cylindrical terminal, the threading action for that PCB hole is completed. Subsequently, laser welding joins the cylindrical terminal with the copper wire, and a hot air blower fuses the heat shrink tubing with the cylindrical terminal. Pneumatic grippers grasp the threaded cylindrical terminals. Simultaneously, an XY-axis servo stage with clamping fixtures places the disc into the clamping fixture, moves it beneath the pneumatic grippers, and inserts the cylindrical terminals into the disc. After completion, a few centimeters of copper wire in front of the rollers are cut, marking the completion of the needle placement for that hole on the disc. The combination of PCB hole wire threading and disc hole needle placement constitutes one cycle of the wire threading fixture. The machine repeats this automated sequence until the entire needle probe fixture is produced. [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]

An increasing need for fast and reliable models has led to a continuous development of Fourier-based (FB) analytical modeling. This paper presents an overview of the techniques that are currently available in FB modeling for electric machines. By coupling that overview to the most relevant literature related to the subject, an interesting starting point is provided for anyone who wants to use or improve FB models. The following seven aspects of FB models are discussed in detail: 1) the magnetic potential (scalar or vector potential); 2) the coordinate system and the solution of the partial-differential equations for each magnetic potential and for each coordinate system; 3) the way in which time dependence is accounted for; 4) the implementation of the source terms; 5) the possibilities to account for slotted structures; 6) the modeling of eccentricity; and 7) the post-processing computation of physical quantities, such as flux density, electromotive force, torque, losses, and eddy currents in conductive objects. Furthermore, this paper gives the closed form solution of the Laplace, Poisson, and Helmholtz equations in each coordinate system. In addition, this paper tackles other important features of FB models such as computational time reduction and coupling the machine model to an electric circuit. [ABSTRACT FROM AUTHOR]

This paper describes the impact of changes in harmonic distortion on the value of the transformer K-Factor. The transformer has a capacity of 1.5 MVA and a K-Factor value of 1 under normal conditions. Techniques were installed to reduce harmonic distortion, shunt passive filter, and detuned reactor. Several condition scenarios were created to compare changes in harmonic distortion's value to the K-factors value. Scenario 1, the transformer works in harmonic conditions. The K-factor value of the transformer becomes 3.947101, and the new capacity of the transformer that can serve the load becomes 1.27 MVA. Scenario 2, a passive shunt filter was installed in the transformer circuit. Shunt passive filter can reduce IHD-V and THD-V values on PCC but increase IHD-I and THD-I values on the load side. The k-factor value fell to 1.5775, and the new capacity of the transformer increased to 1.44 MVA. The novelty of this paper is in scenario 3, a combination of a passive shunt filter and a detuned reactor was installed in the transformer circuit. The detuned reactor can limit the harmonic current that enters the harmonic filter. As a result, all values, including IHD-V, THD-V, IHDI, and THD-I fell below the maximum harmonic distortion limit. The k-factor value fell to 1.0361, and the new capacity of the transformer increased to 1.49 MVA. The existence of a detuned reactor has been able to increase the performance of the passive shunt filter. The impact of the detuned reactor for future research is that it can be used to protect important equipment in the electric power system. [ABSTRACT FROM AUTHOR]

A call for papers for 2014 IEEE International Reliability Physics Symposium on topics related to circuits and products and devices process and materials reliability.

This paper introduces the properties of a fractional-order chaotic system described by the Caputo derivative. The impact of the fractional-order derivative has been focused on. The phase portraits in different orders are obtained with the aids of the proposed numerical discretization, including the discretization of the Riemann-Liouville fractional integral. The stability analysis has been used to help us to delimit the chaotic region. In other words, the region where the order of the Caputo derivative involves and where the presented system in this paper is chaotic. The nature of the chaos has been established using the Lyapunov exponents in the fractional context. The schematic circuit of the proposed fractional-order chaotic system has been presented and simulated in via Mutltisim. The results obtained via Multisim simulation of the chaotic circuit are in good agreement with the results with Matlab simulations. That provided the fractional operators can be applied in real-worlds applications as modeling electrical circuits. The presence of coexisting attractors for particular values of the parameters of the presented fractional-order chaotic model has been studied. [ABSTRACT FROM AUTHOR]

In the electric power industry of Ukraine, the main system-forming objects are power transmission lines and substations with 330(220) kV switchgear. The most powerful sources of danger at substations are short circuits on the busbars, a direct lightning strike or the operation of overvoltage limiters and arresters.The purpose of the article is to develop a method for determining the resistance of the grounding system of substations with open switchgear 330(220) kV, aimed at increasing accuracy, taking into account the most influential independent factors. The provisions of the theory of experiment planning, the theory of electric circuits, mathematical modeling in the package Grounding 1.0, LiGro and Microsoft Excel were used to conduct the research. In the paper, a comparative analysis of the known formulas for determining the resistance of the grounding system is carried out: the formula of the GOST 12.1.30-81 standard, Ohlendorf-Laurant, Laurent and Neumann, Schwartz, Sverak formulas, as well as the formula of the international standard IEEE Std 80-2013. The results of multifactorial experiments to determine the dependence of the resistance of the grounding system on its area, the size of the grid cell, the perimeter of the cross-section of the grounding, the equivalent specific resistance of the soil, the short-circuit current and the depth of the grid location are given. A graphical comparison of the results of determining the resistance according to the considered formulas was carried out. In the paper, the method of determining the parameters of grounding system of 330(220) kV substations was further developed, aimed at ensuring standardized values of the resistance of the grounding system and the ground potential rise using formulas obtained from the results of multifactorial experiments. The results obtained in the work will make it possible to reduce the probability of damage to the insulation of 6- 10 kV cables, as well as cables of secondary circuits from low-frequency and high-frequency (pulse) voltages when large currents flow into the grounding system in the mode of a single-phase short-circuit to the ground in electrical grid with a grounded neutral. [ABSTRACT FROM AUTHOR]

Introduction: Electromagnetic dampers, that are composed of a permanent-magnet DC motor, a ball screw, and a nut, are one of the devices currently being inspected to regenerate energy from the vehicle suspension system. In view of that, this research paper focuses on developing mathematical model for an energy storage system in conjunction with the electromagnetic damper for the sake of energy regeneration of the vehicle suspension system. Methods: The energy storage system considered herein comprises of a unidirectional converter, a full wave rectifier, and an ultracapacitor stack. Some of non-idealities that affect the act of the converter are considered for modeling of the energy storage system. Subsequently, the vehicle suspension system performance analysis along with energy regeneration is carried out based on the developed mathematical model and the role of resistance R (design parameter) in the electric circuit on the vehicle suspension system performance is revealed. Furthermore, considering the variable resistance, a simple method to adjust the parameter of the continuous skyhook control strategy for the semi-active electromagnetic suspension system is proposed in this paper. Results: The simulation results demonstrate that the designed semi-active electromagnetic suspension system has the better performance and more energy regeneration than the passive electromagnetic suspension system. [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]

The paper investigates the controllability of fractional descriptor linear systems with constant delays in control. The Caputo fractional derivative is considered. Using the Drazin inverse and the Laplace transform, a formula for solving of the matrix state equation is obtained. New criteria of relative controllability for Caputo’s fractional descriptor systems are formulated and proved. Both constrained and unconstrained controls are considered. To emphasize the importance of the theoretical studies, an application to electrical circuits is presented as a practical example. [ABSTRACT FROM AUTHOR]

Introduces the themes of the research papers featured in the October 2005 Special Issue of the "IEEE Journal of Solid-State Circuits." Description of a high-efficiency C-band amplifier for satellite communication systems; Presentation of experimental circuits in the InP DHBT technology; Development of a 220-GHz low-noise amplifier for use in high-resolution active and passive millimeter-wave imaging systems.

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]

A transient and static hybrid-triggered active clamp is proposed in this paper. By skillfully incorporating different detection mechanisms, the proposed clamp achieves enhanced static electrical overstress protection capability over the transient one. Furthermore, the proposed clamp achieves improved electrostatic discharge reaction speed in both human body model and charged device model events over the static one. Moreover, the superior transient-noise immunity of the proposed clamp over traditional transient ones is essentially revealed in this paper. The proposed clamp is successfully verified in a 65-nm bulk CMOS process. In addition, the design flexibility of the proposed clamp for other processes is also deeply discussed in this paper. [ABSTRACT FROM PUBLISHER]