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Summary As an emerging energy-harvesting technology, enhancing the output performance of triboelectric nanogenerators (TENGs) is crucial for its practical application. Here, a dielectric enhancement effect is firstly proposed to improve the output performance of TENGs. It is found that the dielectric enhancement layer greatly elevates the triboelectrification effect, and the enhanced performance is verified by all types of TENGs. Thus, the output power of alternative current TENG (AC-TENG) and direct current TENG (DC-TENG) realizes 8.5-fold and 2.6-fold enhancement of normal devices, respectively. Besides this, the dielectric enhancement layer with leakage performance is proven to be necessary for DC-TENG to produce a continuous output. Our work provides a simple and universal strategy for elevating the performance of all types of TENGs, which is beneficial to the promotion of large-scale energy harvesting by TENGs.

The linear momentum density carried by electromagnetic fields creates the hidden force acting on the displacement current between ends of an unclosed conductor with alternative electric current. This force compensates the self-force exerted by the unclosed conductor with zero thin. The magnetic field produced by displacement current does not contribute to the force acting on the conductor. The unclosed conductor can move under action of the self-force. At small heights of cylindrical open conductor, the reactive force equivalent to the self-force becomes very large

En la actualidad, la competitividad ocupa una de las discusiones centrales en el ámbito académico y empresarial, respecto a cuáles son los factores que la afectan y permiten a las organizaciones diferenciarse de su competencia y generar una ventaja competitiva en el mercado. En este contexto, la teoría de los recursos y las capacidades (VBR) ha surgido como una corriente alternativa que basa la fuente de competitividad considerando las habilidades y las dimensiones internas de la organización. Entre ellas, se ha expuesto que son factores como el marketing, gestión, innovación calidad y talento humano aquellos que puedan tener un impacto directo en la competitividad de las organizaciones dedicadas a servicios hoteleros. Es así que se propone, desde un enfoque formativo, un análisis factorial confirmatorio que permita dilucidar los factores claves que afectan la competitividad en el sector hotelero. Para tales fines, se plantean unas encuestas en el sector hotelero de Sucre arrojando como resultado que son los factores del talento humano y la innovación aquellos que posibilitan la construcción de competitividad en este sector y en menor medida el marketing, la dirección y la calidad. A partir de estos resultados se plantean unas discusiones respecto a la importancia de los factores claves en la competitividad del sector.

This paper proposes an alternative current alpha plane protection for shunt reactors, which is able to identify internal faults, including turn‐to‐turn faults. The proposed algorithm is based only on zero sequence and neutral currents, eliminating the need for voltage measurements. Furthermore, the proposed algorithm is based on an alternative current alpha plane, where the restraint characteristic is defined simply as its left half‐plane, in such a way that minimal settings are required. In order to evaluate the performance of the proposed algorithm, the Alternative Transients Program was used to simulate different internal faults into an air‐core dry‐type shunt reactor connected to a 230 kV/60 Hz transmission line. The proposed algorithm performance was compared with the restricted earth fault function. From the obtained results, it is demonstrated that the proposed protection properly operates in turn‐to‐ground and turn‐to‐turn faults with operation times shorter than one power cycle, even for 1% of short‐circuited turns. On the other hand, restricted earth fault function failed to operate in some of these cases. The proposed algorithm ensured the integrity of the air‐core dry‐type shunt reactors in all evaluated scenarios, correctly restraining in all simulated external faults (including cases with current transformer saturation). Thus, the proposed algorithm is considered a reliable and promising alternative for shunt reactors protection.

Alternative current electroluminescence (ACEL) can be identified as an efficient light-emitting technique among a number of different light emission methods. Open-air fabrication capability of the ...

Transcatheter electrosurgery refers to a family of procedures using radiofrequency energy to vaporize and traverse or lacerate tissue despite flowing blood. The authors review theory, simulations, and benchtop demonstrations of how guidewires, insulation, adjunctive catheters, and dielectric medium interact. For tissue traversal, all but the tip of traversing guidewires is insulated to concentrate current. For leaflet laceration, the "Flying V" configuration concentrates current at the inner lacerating surface of a kinked guidewire. Flooding the field with non-ionic dextrose eliminates alternative current paths. Clinical applications include traversing occlusions (pulmonary atresia, arterial and venous occlusion, and iatrogenic graft occlusion), traversing tissue planes (atrial and ventricular septal puncture, radiofrequency valve repair, transcaval access, Potts and Glenn shunts), and leaflet laceration (BASILICA, LAMPOON, ELASTA-Clip, and others). Tips are provided for optimizing these techniques. Transcatheter electrosurgery already enables a range of novel therapeutic procedures for structural heart disease, and represents a promising advance toward transcatheter surgery.

The paper is devoted to the study of post-emergency operating modes of a multichannel frequency converter, made on the basis of static transformer phase control devices. The results of computational experiments obtained on the structural-simulation model, which prove the possibility of providing asynchronous alternative current controlled intersystem communication (CIC) in case of emergency shutdown of several converter channels, are presented. The possibility of ensuring the qualitative characteristics of the conversion in various variants of a post-emergency situation evolution with a different number of simultaneously operating channels of the device is illustrated.

This study investigated the piezoelectric response of a smart concrete (MSF) containing fine steel slag aggregates (FSSAs) and steel fibers under high compression by measuring the alternative current impedance. The electrical resistivity of MSF notably decreased (15.65%) with the increase in the applied compressive stress from 20 to 100 MPa, whereas the electrical resistivities of smart concretes containing only FSSAs or steel fibers or both multiwalled carbon nanotubes and steel fibers reduced by 9.62, 12.37, and 9.30%, respectively. The MSF with a linear piezoelectric response under compression (until 60 MPa) was applied to a prestressing steel anchorage zone to monitor the loss of prestressing stress.

To examine the feasibility of low-charge electrotherapy (LCE) in treating geriatric major depressive disorder (MDD) patients. Bi-temporal LCEs (approximately 25 mC) were performed with an electroconvulsive therapy (ECT) instrument three times per week. We used the Hamilton Depression Scale 17 (HAMD-17) and the Hamilton Anxiety Scale (HAMA) to assess the effects of LCE and the Mini-Mental State Examination (MMSE) to evaluate the cognitive function change before and after LCE. Six visits occurred at the baseline, after LCE sessions 3, 6, and 9, after the last session, and at the end of the one-month follow-up period. Four patients were enrolled in the study. Two patients completed all LCE sessions. Two patients withdrew during the trial, one due to the adverse event of uroschesis potentially caused by atropine and the other due to her own will. All four patients completed the follow-up sessions. The HAMD-17 and HAMA scores were reduced significantly at the last LCE session and the end of the follow-up period compared with the scores at the baseline. As measured by the MMSE, cognitive impairment showed no significant changes at the last LCE session and the end of the follow-up period compared with that at the baseline. In this case series, LCE showed potential as an alternative current-based treatment for treating geriatric MDD patients. Further research is needed to assess the efficiency and safety of LCE.

There is a direct analogy between the mechanical and electrical phenomena related to vibrations and electromagnetic oscillations in the RLC series AC circuits and an inverse analogy to the electromagnetic oscillations in the RLC parallel alternative current (AC) circuits. Direct analogy RLC series AC circuit refers to the connection between complex velocity and complex electrical intensity, mechanical impedance and electrical impedance, etc. Reverse analogy RLC parallel AC circuits refers to the connection between complex velocity and complex electrical voltage, mechanical impedance and electrical admission, etc.

The article considers development of an alternative current source for contactless electric power supply to superconducting excitation windings of electrical machines for on-land and aircraft applications. Based on the results of experimental investigations, the output characteristics of a photovoltaic generator constructed on the basis of the TCM-105F module and operating under the conditions of natural and artificial lighting are subjected to a comparative analysis. The possibility of using the photovoltaic generator as an alternative source of power supply for the superconducting excitation windings of contactless electrical motors and generators is shown. Schematic layouts of the power supply system for rotating superconducting windings with the use of a photovoltaic generator are proposed.

Electroluminescence (EL), the light emission under an applied electrical potential, is one of several key light emitting techniques applied over a vast range of applications. Alternative Current Electroluminescent (ACEL) is one of the major light emitting techniques discussed under EL. Even though it possesses some intrinsic advantages over Light Emitting Diodes (LEDs) and Light Emitting Cells (LEC), it has not been thoroughly discussed like LEDs and most of the time has been kept under the shadow of LEDs. On the other hand, flexible light emitting devices have become an emerging trend in the field as they are widely applied in consumer electronics and wearable devices, where an ACEL technique can make a significant impact for their development. This review discusses the ACEL technique in detail covering different device architectures, materials and fabrication methods highlighting the use of electrospinning techniques. In the second part, the review briefly summarizes research works in the flexible light emitting field, covering both optical and mechanical performances.

REBCO tape is one of the most popular high temperature superconductors (HTS) in recent years. As a commercial HTS conductor, REBCO tape can be used in high power density and efficiency applications. However, AC loss is an important issue when REBCO tape is applied in the alternative current condition. Narrowing the RECBO tape width is considered as an efficient method to reduce AC loss in REBCO coil. Some researches had confirmed the narrowing effect for AC loss reduction. But, the related experimental works are usually based on the small size REBCO coil, and other simulation works are also limited by calculation speed. The influence of coil size on AC loss reduction by narrowing the REBCO tape is demanded to be analyzed. In this paper, we proposed to use T-A formulation method for improving the calculation speed of the large size REBCO coil, which can study the narrowing effect in different coil sizes. Specifically, the REBCO tapes of different width is modeled for comparison and the value change of AC loss in small size coil and large size coil will both be discussed. This work will conduct the narrow REBCO tape to be used more appropriately.

The distribution system is the nearest part of the power network to the consumers; so, the efficiency of the distribution system has the effect on the satisfaction of customers from the network. The optimal operation of the distribution flexible alternative current transmission system (DFACTS) is one of the useful ways to increase the efficiency of the distribution system. These devices compensate the reactive power and improve the technical performance of the network. On the other hand, applying demand response programs can promote the efficiency of DFACTS devices. As regards the importance of power electronic compensators in the power network, the optimization of location and capacity of DFACTS is studied in the distribution system in the presence of DR program. The combination of multi-objective optimization algorithm and analytical hierarchy process method is utilized to minimize the considered objective functions and select the optimal place and size of DFACTS devices.

This paper presents simulation and calculation results of electric field enhancement due to various cavity shapes in polymeric high voltage direct current (HVDC) cables. Two aspects are considered: field enhancement factor under DC and partial discharges (PD) in microcavities. PD can occur within defects already existing inside crosslinked polyethylene (XLPE) matrix under various conditions. These conditions are well known under alternative current (AC) but not so well under DC and DC with harmonics. Charges accumulation at XLPE/void interfaces are responsible for local field enhancement and discharges. Aim of this investigation is to identify if these effects, once combined, can increase microvoids size.

Memristor and memristive systems are nonlinear systems. It is important to model them accurately. There are different memristor models and most of the models make use of window functions. In literature, there are various window functions. Recently, a piecewise linear (PWL) window function is used to model a memristor and memristive systems. Such a memristor with a PWL window function lacks a SPICE model. Also, in literature, there is current polarity dependent window functions proposed for memristors to model polarity dependent drift speed within the thin-film memristors. In this study, an alternative current-polarity dependent PWL window function is suggested to model a memristor, a different PWL function one for each current polarity is used, its SPICE model is made in LTSpice and also its simulation results are given. Such a model can be used to model the polarity dependent drift speed within the thin-film memristors. © 2020, Gazi Universitesi. All rights reserved.

The article describes mathematical model of three-phase alternative current electric arc furnace with mutual in-ductances between phases. The results of mathematical modeling show that mutual inductance causes sufficient impact on balance of active power in three phases. This feature must be considered during parametrization of the electric mode control system. Otherwise, the "transfer of power" effect from one phase to another may led to overheating of the water-cooled panels and early wear of the fireproof brick lining. Prevention of such negative factors allows to minimize production loses and increase general quality factors of steelmaking workshop.

Body in disembodied reality. The „Pitch-In Culture” and „Tango”This is an essay about PITCH-IN CULTURE — an alternative current, alternative group of artists, who in the 1980s in Lodz had created an autonomic space, an artistic shelter which let them function away from an official, mainstream structures of life and its culture designed by the state. Counterculture from Lodz, rebelling against reality and fictional freedom created by author­ities, found its space in the city centre, in the attic of one of townhouses. THE ATTIC had be­come an agora of underground, place of transgression of enforced schemes, clichés, patterns and truths. According to an idea — DO IT YOURSELF — DIY they published handmade magazine with art works that aroused or were related to sexual desire, often incorporating nude figures.

Dynamic changes in the charge-transfer resistance at a Li/Li 7 La 3 Zr 2 O 12 (LLZ) interface during lithium (Li) dissolution/deposition cycles are investigated with an alternative current (AC) impedance technique in a three-electrode system. The resistance respectively increases and decreases during electrodissolution and electrodeposition of Li. The resistance does not return to the initial value after one cycle of Li dissolution and deposition, which indicates that the change in resistance during dissolution is larger than that during deposition. Furthermore, the resistance is almost constant when Li deposition proceeds without prior Li dissolution. The respective increase and decrease in the interfacial resistance during Li dissolution and deposition is most likely due to the formation and disappearance of voids at the Li/LLZ interface, and the voids formation during Li dissolution is suggested to be a critical factor that influences the interfacial resistance.

The aim of this work is to produce novel bioelectricity using tannery leather fleshing (TLF), carbon nanoparticles (CNP) from vegetable waste and poly ethylene glycol (PEG). Tannery leather fleshing solution (TFS) was produced from TLF. Nanopolymeric blended solution (NPBS) was produced using TFS and reinforced using various proportions of CNP and PEG. Physico-chemical characterization has clearly revealed the chemical nature, elemental composition and thermal stability of NPBS. The microstructure and electrical conductivity of the NPBS were elucidated by scanning electron microscopy and cyclic voltameter respectively. NPBS produced with 3% CNP demonstrated high electrical conductivity (voltage: 1201.13 + 1.00 mV per cell, current: 749.42 + 0.56 mA per cell and resistance: 98.77 + 0.57 ? per cell). The study provides an opportunity for utilization of solid leather waste generated by tanneries for production of eco-friendly bioelectricity. It also paves an economical way to make direct/alternative current and batteries. © 2021 The Authors, 118C350, Dr. Senthil Rethinam (Project Coordinator) acknowledges the funding support granted by the 2232-International Fellowship for Outstanding Researcher Program of TUBITAK (Project No: 118C350).

The protection of high voltage alternative current (HVAC) cables is of paramount importance, because conventional distance relays are not capable to precisely determine the fault location. The mutual inductances between core and sheath in HVAC cables as well as significant capacitive effects exert undesirable impact on the seen impedance by distance relays. Thus, in this paper, a new analytical method is proposed for fault location in HVAC cables employing measured voltages and currents at both ends. In the proposed method, the cable is modeled adopting the distributed form of the main parameters. The proposed fault locator searches the entire length of the cable to determine the location of core-to-sheath faults as well as the corresponding fault resistance. To implement the algorithm established in this study, a HVAC underground three-phase single-core cable is simulated in PSCAD/EMTDC environment. Comprehensive simulation studies are conducted by considering different bonding methods, fault resistances and fault locations. Moreover, the performance of the proposed fault locator is evaluated in different operating conditions including noisy environments, source impedance changes, different load levels, high fault resistance, and uncertainties in cable parameters. The results demonstrate that the estimation error does not exceed 1%, which is desirable for practical applications.

A low-temperature flowing postdischarge plasma reactor is first presented. The reactor is a postdischarge chamber coupled to a plasma jet system. The low-pressure flowing postdischarge (jet) in the postdischarge chamber can be generated using direct current (dc) or alternative current (ac) power supplies. A low-pressure plasma jet of Neon using a 25-kHz 25-kV ac voltage and low-pressure plasma jet of ambient air using a 5-kV dc voltage produced in the postdischarge chamber are given. By using sample holders in the postdischarge chamber, early or late flowing postdischarge (jet) can be exposed to the sample surface. In this paper, the low-temperature and low-pressure dc air plasma jet generated using the plasma jet system coupled to a postdischarge chamber is first exposed on to Bacillus cereus , as a model bacterium. The inactivation effect on Bacillus cereus of the low-temperature and low-pressure dc air plasma jet at several exposure times was observed. With treatment of 30 min of exposure times, a value below the decimal value of the used bacterium was obtained of 15 min of exposure times.

This paper reviews the evaluation of hydration of cement-based materials by means of electrical methods from the view point of direct and alternative current methods. The merits, demerits and application scenarios of electrical methods for hydration characterization are described. Influencing factors (pore solution conductivity, porosity, pore size distribution and pore connectivity) of electrical methods are briefly commented. Besides, the predictions of setting time and shrinkage, and the determination of hydration stages by electrical methods are presented. The combinations of some mainstream computer simulations and electrical methods are reviewed.

In this paper, the impact of the conductivity and the distribution of pollution on the behavior of the high voltage insulator cap and pin 1512L, artificially polluted is described. An experimental model in form of a disc is proposed. This experimental model reproduces the real model which is the 1512L insulator. Besides, a comparative study is presented. For this comparative study, different solutions are adopted to s`imulate the pollution (containing NaCl + distilled water) that has different conductivities for a discontinuous distribution of the pollution on the insulator under an AC voltage. Furthermore, the influence of the pollution on the flashover voltage and the leakage current is studied. Finally, the behavior of real and experimental model of the insulator is investigated.

A few multi-terminal direct current (MTDC) systems are in operation around the world today. However, MTDC grids overlaying their AC counterpart might a reality in a near future. The main drivers for constructing such direct current grids are the large-scale integration of remote renewable energy resources into the existing alternative current (AC) grids, and the promotion and development of international energy markets through the so-called supergrids. This paper presents the most critical challenges and prospects for such emerging MTDC grids, along with a foreseeable technology development roadmap, with a particular focus on crucial control and operational issues that are associated with MTDC systems and grids.

The instability problems in the electrical supply networks have had a great impact on recent research studies on modern devices. The unified power flow controller (UPFC) is one of the various FACTS (Flexible Alternative Current Transmission Sys-tems) devices that allow the electrical supply networks to be stable with a strong effectiveness. In this paper, the performances of such a device using both a classical PI and a variable gains PI controllers are examined. For this instance, the compensator is first stabilized before trying to stabilize the network. A series of comparative simulation tests have been undertaken for both regulators and analyzed. From the obtained results it is clearly shown that when the system is equipped with the variable gain PI regulator, the performance are much better.

As the number of direct current (DC) customers is currently expanding, and distribution lines are changing from alternative current (AC) to DC accordingly, DC distribution lines with a radial structure are also becoming longer. This paper includes an analysis of the characteristics of fault currents in LVDC systems, and proposes a protective coordination method, utilizing AC/DC converters and protection equipment when a fault occurs in direct current lines with radial structure, that has been effectively demonstrated in field verification tests.