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This research presents a dynamic modeling approach to predict flashover voltage (FOV) of polymer insulators. Pre-flashover conditions can be used to represent analytical formulations for different stages of dry band arcing activities on the surface of polluted insulator. In this study, experimental results of pollution flashover tests are used to develop a circuit model of pollution arcs based on Obenaus model. Estimation of circuit values is done by use of intelligent algorithm with no dependency on profile of insulators which is also more beneficial than typical analytical calculations. Then, separation and investigation of discharge and pollution voltage is done and proper classification is made. This classification is later used to predict pre-flashover conditions and pollution flashover. Gaussian model is used to make fitness of voltage of pollution layer and voltage of discharge on the surface of insulator. Gaussian representation of each stage in pollution flashover contains critical signals leading to complete discharge. Based on the obtained model, a flowchart is presented to predict dynamic stages of flashover. Comparison to various experimental data shows close correlations with the results of proposed model. An online monitoring system can be developed according to obtained results in order to prevent pollution flashover.

This study numerically simulated and investigated the flow field characteristics of a typical dual-pulse solid rocket motor with a soft pulse separation device through thermal insulation ablation under high-temperature dual-pulse erosion. The ablation rate of ethylene -propylene-diene monomer (EPDM) insulator was measured after the experiment. Experimental results were analyzed through scanning electron microscopy and microcomputed tomography. The ablation mechanism of the EPDM insulator under the operation conditions of a dual-pulse solid rocket motor was evaluated by analyzing the results. The results reveal that the internal flow field of the motor with a soft pulse separation device is uniform. The original charred layer existing on the EPDM insulator surface in the first pulse combustor is the decisive factor affecting the final ablation rate of the dual-pulse motor during the second pulse operation, and the ablation characteristic region is easily formed with the exfoliation of the charred layer. The ablation rate difference of the insulator increases with gas velocity.

Toughened glass insulators installed in overhead lines play a key role in maintaining the reliability and safety of power systems. The singular properties of toughened glass make this material particularly suitable for this application on account of its excellent dielectric properties, high mechanical strength and easiness of inspection. If the glass was damaged, it would shatter completely leaving the remaining part of the insulator, called stub, still providing mechanical connection and being easily detectable from the ground by a visual inspection. In this paper, the mechanical reliability of toughened glass insulators is investigated through the analyses of experimental data obtained from laboratory tests. First, the mechanical strength of the toughened glass in insulators and the relationship between its failing load and the geometry of the insulator are investigated by means of a novel analytical approach. Afterwards, the risk of mechanical failure of glass insulators and stubs, with the shell broken off, is analysed. The results show the mechanical reliability of glass insulators for different string configurations and for large and complex systems deployed in 220 kV and 400 kV transmission lines. Finally, the effect of the shattering rate on the reliability is studied under the most adverse conditions.

The dynamic impact load after a single insulator of a tension composite multi-strings of insulator (MSI) set has failed is a key factor that should be considered in design. In this paper, an experimental method to obtain the dynamic tensile impact factor (DTIF) is established by considering a typical double-strings set, which is commonly used in practical engineering. A nonlinear numerical simulation method based on the finite element model, which is convenient for cases that are more complex than the double-strings set, is proposed to calculate the DTIF and demonstrated through the experimental results. The values of the DTIF on the unbroken insulator string obtained by the experimental models fall between 2.6 and 3.3, which should be a very valuable reference for the design of composite MSI sets. The size of connection fittings is a key factor that influences the DTIF, and the yoke height between the insulator strings and the conductors is the most sensitive parameter. The application of the proposed method to calculate the DTIF can improve the existing design approach to ensure the safety of the tension composite MSI sets, especially for high voltage transmission lines.

In various technical areas, the requirements and the complexity of electrically conductive structures (cables, printed circuit board traces) and their insulating materials are increasing, which leads to higher demands on reliability. Therefore, better diagnosis and control functions are needed. Intelligent fusing strategies with electronic fuses, where the current flow can be switched by semiconductors, can play an important role. One approach is to monitor the insulation temperature in order to detect thermal overloads and switch-off a current branch before the insulation is damaged. As especially in cables, a direct temperature measurement is troublesome, most approaches are based on current measurements. From a measured current, the cable insulator temperature can be derived using an electrothermal model. Those models can be very complex, especially when the transient and axial heat flow in a cable should be considered. The computational efforts for the commonly used numerical solution methods are high. Analytical approaches potentially reduce these efforts significantly. In this contribution, a new analytical approach for the calculation of the transient axial temperature distribution along an insulated single wire cable considering the nonlinear temperature dependency of the cable parameters is presented. It enables a precise and fast calculation of cable temperatures.

In electrified railways, pantograph-catenary (PC) arc frequently occurs in the process of train passing through split-zone insulator, which threatens the current collection of PC and operation of electric multiple units (EMUs). So far, there has been few studies on the analysis and modeling of the PC arc on split-zone insulator. It is noting that this research is different from that of split-phase region. This paper firstly analyzes the dynamic variation process of PC distance as EMUs pass the insulator, and deduces the formula which can reflect the PC arc length variation according to the specific mechanical structure of insulator. Then, a black-box arc model of split-zone insulator is proposed. Next, a vehicle-grid model of the EMUs which contains the arc model of split-zone insulator is established to simulate and analyze the characteristics of the PC arc on split-zone insulator. Further, the proposed arc model in this paper is verified by comparing the simulated arc characteristic waveforms with the measured results. Finally, a sensitivity analysis of the arc model under different lifting angles of the contact wire is carried out in order to analyze the suppression of PC arc on split-zone insulator.

The domino-resonator wireless power transfer (WPT) system is designed in this work to harvest energy from the magnetic field around a 110-kV high voltage transmission line (HVTL) and transmit the power to the online monitoring equipment continuously over 1.1 meters insulation distance. Each domino-resonator is evenly spaced and is embedded inside totally sealed insulation discs. The theoretical analysis shows that the constant voltage (CV) mode and the constant current (CC) mode can be realized by adjusting the receiver's switch state, which can meet the battery's CV and CC charging requirements. Such a method cancels the communication between the transmitter and the receiver. The finite element simulation results show that the influence on the electric and magnetic field intensity distribution near the insulator can be negligible. Finally, a 30W prototype with an output voltage of 7V is built. The experimental results show that the fluctuation of output voltage (CV mode) and output current (CC mode) is less than 6% and 7%, respectively. The maximum efficiency is higher than 40% when the transmission distance is 1.1m, and the number of coils is 12.

An automatic detector device (ADD) has been designed and built for monitoring insulators state in overhead distribution lines. The prototyped device is suitable for measurement and analysis of the insulator leakage current ( LC ) on lines of distribution systems to diagnose insulator state. It operates based on two diagnostic indicators, third to fifth harmonic ratio (R3/5%) of the insulator's LC signal and cosine of phase angle difference (P.D%) between fundamental signals of the voltage and LC . Experimental data of the indicators in various conditions and various insulators are used to train a classifier for determining reference values of the indices for insulator state detection. The instrument has two physically separate parts: receiver and transmitter. They communicate via a radio communication channel which improves the effectiveness of incident management. The transmitter samples the LC signal of the target insulator using a ferrite core along with a series of active electronic filters. The sampled LC signal is then sent to the receiver. The transmitted LC signal is analyzed by the microprocessor embedded in receiver CPU. Indicators of the transmitted LC signal are calculated and compared with reference values extracted from the classifier. The receiver determines the insulator's state based on the comparison of the estimated and reference values of diagnostic indicators for the target insulator. The performance of the prototyped ADD was evaluated experimentally in the laboratory as well as on overhead distribution lines. These performance tests confirmed reliable performance of the ADD.

The catenary insulator maintains electrical insulation between catenary and ground. Its defects may happen due to the long-term impact from vehicle and environment. At present, the research of defect detection for catenary insulator faces several challenges. 1) Localization accuracy is low, which causes the localized object to be incomplete or/and merge with unnecessary background. 2) Horizontal localization brings inevitable unnecessary information because horizontal box cannot fit well with the shape of insulator. 3) Supervised learning models for defects recognition are unreliable as the available defect samples are insufficient to train models well. To address these issues, this article proposes a novel two-stage defect detection method. In the localization stage, a novel localization network called TOL-Framework is constructed to reduce the background and realize tighter oriented localization. Compared with general basic framework Faster R-CNN, the TOL-Framework cascades a regression module inside basic framework and adds an external postprocess network, which is adversarially trained by standard insulators to refine the localization. These two novel steps greatly improve the oriented localization accuracy. In the defect detection stage, an adversarial reconstruction model that is trained only using normal samples is proposed to evaluate the defect states. A comparison with other methods is conducted using a dataset collected from a 60km section of the Changsha-Zhuzhou railway line in China. The results show the proposed method has the highest localization accuracy, and is effective for insulator defect detection.

This paper studies the AC pollution breakdown characteristics of the EGLA and broaden current knowledge of pollution flashover. Compared with the flashover of the normal insulator, three kinds of specificity of the EGLA were found. Firstly, the pollution flashover process can be divided into three categories. Secondly, the wet flashover voltage, Uf _wet, of the novel insulator is higher than the dry flashover voltage, Uf _dry. Thirdly, the piecewise fitting methods with aESDD^-b+d and aESDD^-b+ cESDD^-d are more suitable for fitting the empirical formula of flashover voltage. Furthermore, to explain specificity, the electric potential and electric field distribution are calculated based on the finite element method. Calculated results indicate that when the EGLA is covered with a 0.5mm water film, the maximum electric field intensity decreased from 2.17 kV/cm to 1.99 kV/cm. Also, U_arrester (the withstand voltage of the insulation section) was obtained from the tests and it presents a discontinuous and random increasing trend until flashover occurs, which is considered to be one of the important reasons for the specificity. Besides, based on the Obenaus model and Hampton's criterion, we further analyzed the arc development process by a simplified plate model

The surface voltage of an insulator assumes importance for understanding tracking and flashover characteristics. Until now, determination of surface voltage of insulating surfaces is left to simulation software and such simulations are left unverified experimentally, leading to uncertainty of the results, which may sometimes be erratic with improper choice of boundary or initial conditions or inaccurate material properties, nonlinearities etc. The paper presents a novel method, using which the surface voltage of any insulating surface such as insulator strings or transformer bushings can be measured. Unlike a conducting surface, the measurement of insulating surface voltage using voltage dividers would be erratic as the measuring arrangement itself will vary the voltage division due to the local unknown impedance between the insulated surface and hv conductor. Recently a method for measurement of surface voltage of an insulated conductor using cylindrical strips was reported. In this paper, based on analytical derivations, a more generalized method of measurement, applicable to any point on an insulating surface of arbitrary geometry is proposed using circular-disc strips. The proposed experimental method is applied to insulator strings and transformer bushings and validated by simulation of the entire systems. The simulation and experimental results are in excellent agreement.

The adhesion and wetting between metal and ceramic is a basic problem in materials science and engineering. For example, past materials selection for metal-ceramic composites has relied on random trials and heuristics due to a limited understanding of their adhesion; the large chemical/structural variability that such interfaces can have hinders the identification of the governing factors. Here based on literature data, we have developed a database with ∼1,000 experimentally measured wetting angles at different temperatures and atmospheric conditions, and come up with a model for the wettability of ionocovalent ceramics (ICs) by metals using a machine learning (ML) algorithm. The random forest model uses the testing temperature and ∼40 features generated based on the chemical compositions of the metal and the ceramic as predictors and exhibits strong predictive power with an R2 of ∼0.86. Moreover, this model and the featurization code are integrated into a single computational pipeline to enable (1) predicting metal-IC wettability of interest and (2) high-throughput searching of ICs with the desired wettability by certain metals in the entire Inorganic Crystallographic Structure Database. As a demonstration of this pipeline, the wettability of a Li-ion and electron insulator (LEI), CaO, by molten Li is estimated and compared with ab initio molecular dynamics simulation result. This ML pipeline can serve as a practical tool for methodical design of materials in systems where certain metal-ceramic wettability is desired.

Coulomb explosion, characterized by coulomb repulsion between the particles with the same charge on the surface of a material, has been used to realize exquisite nano-manipulation, however, researchers usually only found one aspect of application of Coulomb explosion when they utilized it. Herein, we successfully design a “metal@insulator” based Coulomb explosion process through irradiating oxidized Topological Crystalline Insulator SnTe under electron beam. The occurrence of Coulomb explosion mainly due to the oxide encapsulated SnTe retained the metallic surface state, which not only can be positively charged, but also can realize charge accumulation through the shield effect of the insulate oxide layer. By changing experimental conditions and carefully studying various experimental phenomena, we conclude six aspects of application, namely speculating the metallic surface state of oxide-encapsulated SnTe, controllable fabricating nanoplates, observing the PVD (Physical Vapor Deposition) process under low temperature, rapid coating film, unraveling the oriented attachment and self-recrystallization of larger nanocrystals and fabricating hollow structure. Our findings are important for utilizing of Coulomb explosion as well as other EBI techniques to conduct nano-manipulation.

With the recent progress in electronic skin, wearable medical devices and robotic systems, efforts have been devoted to capacitive proximity sensor and organic semiconductor proximity sensor. The former shows the proximity perception ability towards the conductor, and the latter enables proximity detection of the electrically charged objects. Here, by embedding rubrene organic semiconductor proximity sensor (insulator detector) and a parallel plate capacitive proximity sensor (metal detector) on the polydimethylsiloxane (PDMS) elastic substrate, we merge two-type proximity sensors in a single platform to realize a flexible, conformal composite proximity sensor, which enables good adherence onto the curved objects and detection of fingers, metal, and insulators, showing the strong application potential in wearable electronics.

Porcelain insulators have prodigious importance in electricity transmission and distribution network because of their high dielectric constant, electrical resistivity, and mechanical strength and these properties are closely connected to the microstructural details of the insulator. Three different porcelain insulators (Sample A, B and C) were reported in the present work. X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), three point bending test and density and pore analysis were carried out to investigate the structural and mechanical properties of various insulators. The analysis confirmed that the porcelain insulators are made of industrial alumina, quartz, clay, and feldspar having amorphous as well as crystalline phase in the body. The porosity, density, and bending strength were also calculated and a correlation was developed between mechanical strength of the insulator and various physio-chemical and microstructural properties. Sample A showed the highest value of bending strength i.e. 207.20 MPa and sample C the lowest value of 112.18 MPa while sample B demonstrated the intermediate value of 170.98 MPa. To formulate high strength porcelain insulators, it was concluded that the amount of amorphous phase, dispersed corundum, and mullite content are key factors to control the mechanical strength of porcelain insulators.

The insulation failure is common in high voltage transmission. Based on experimental structure, this paper adopts the finite element method to establish the mathematical model of the short-circuit insulator discharge. Simplify the insulator discharge into a short circuit process between the upper and lower plates, and explore the process of generation, adsorption and neutralization of electrons, positive ions and negative ions, studied how the space charge variation affects the electric field intensity, and analyzed the distribution of each type of ionization products from the wires during the discharge. The results show that: when the insulator is short-circuited and discharged, the area with larger electric field strength is mainly concentrated near the upper plate; the electric field intensity in the discharge space tended to stabilize at the completion of the discharge; when the short-circuit wires were fused, the electron concentration remained stable for a short while at certain positions of the discharge space; as the discharge continued, the electron concentration at these positions declined rapidly; the electrons moved to the plates, causing fluctuations in electric field intensity; the variation of electron concentration during the discharge obeyed the Gaussian distribution. The research results provide the experimental evidence and theoretical reference for avoiding transient discharge in equipment operation.

Fault diagnosis of insulators in aerial images is an essential task of power line inspection to maintain the reliability, safety, and sustainability of power transmission. This paper develops a novel method for intelligent diagnosis of electrical insulators based on deep learning, termed Box-Point Detector, which consists of a deep convolutional neural network followed by two parallel branches of convolutional heads. These two branches are utilized to locate the fault region and estimate insulator endpoints, which presents a new representation for insulator faults. Endpoints of the faulty insulator string can provide detailed and correlative information for enhancing the diagnosis capability of component-dependent faults that occur on component bodies. The proposed Box-Point Detector implements all predictions including region and endpoint into one network thus forms an efficient end-to-end structure, and adopts a smaller downsampling ratio to generate high resolution feature-maps in order to preserve more original information for small size faults. Experimental results indicate that Box-Point Detector can accurately diagnose high-voltage insulator faults in real-time under various conditions. Compared with some previous works using Faster R-CNN, SSD, and cascading network, our Box-Point Detector shows more competitively capabilities with high accuracy and robustness.

The paper explores the comparative biosensing analysis of single Gate (SG) and double Gate (DG) Extended Source Tunnel FET (ESTFET). The dielectric modulation technique has been incorporated for both the proposed biosensors with increased capture area by introducing nano-cavities near the source and drain region. The biosensing performance parameters like Threshold Voltage Sensitivity ( $\Delta\text{V}_{th}$ ), ON-OFF Current Ratio Sensitivity ( $\Delta\text{I}_{\text{ON}}/\text{I}_{\text{OFF}}$ ), and Drain Current Sensitivity ( $\Delta \text{S}_{Id}$ ) are calculated and compared for both the SG-ES and DG-ESTFET based biosensors. Sentaurus TCAD simulator is used for the investigation reported in this paper. The analysis includes neutral, positively and negatively charged biomolecules for various dielectric constants at immobilization layer and biomolecule analogous insulator interface. Further, a comprehensive analysis of partly filled nano-cavity originated from steric hindrance has been conferred to engulf the real time scenario. Different cases of partly filled nano-cavity have been considered to investigate the sensitivity parameters such as convex, concave, increasing and decreasing step profile along with asymmetric probe placement. It is observed that SG-ESTFET based label free biosensor outperform the DG-ESTFET due to the impact of back gate on the drain side nano-cavity. Some important bio-sensing parameters are estimated to have the subsequent values for SG-ESTFET (DG-ESTFET) as 80 mV (74 mV) for threshold voltage sensitivity, $23\,\,\times10$ 3 ( $15\,\,\times10$ 3 ) for ON-OFF current ratio sensitivity and $60\,\,\times10$ 2 ( $45\,\,\times10$ 2 ) for drain current sensitivity, respectively. Lastly, different sensitivity parameters of SG-ES and DG-ESTFET are gauged against sensitivities of state of the art biosensors to set out the high sensitivity of our proposed biosensors.

The thermographic diagnostic of substation insulators can facility to detect their insulation status in time. However, the detection effect of infrared insulator images is usually poor due to the complex background of substation scene images. In order to solve this problem and improve the automatic detection capability of substation equipment, an infrared insulator image detection model based on the improved feature fusion single shot multibox detector is proposed in this paper. The model combines multi-scale feature maps to generate a new feature pyramid, and designs a new feature enhancement module in the shallow network of the model to improve its ability to extract features of infrared images of substation insulators. Meanwhile, the clustering algorithm is used to calculate the target aspect ratio information of the dataset to realize the adaptive change of the aspect ratio of the default box. Furthermore, the transfer learning is employed to further improve the learning efficiency of the model. Before the formal experiment, the design scheme of feature enhancement module is confirmed by ablation studies. Experiments are performed on the collected infrared insulator images, transformer images and Pascal VOC 2007 dataset. It is demonstrated experimentally that this model achieves excellent detection results.

Insulator pollution flashover occurs frequently and is harmful to the power transmission and distribution network. But the randomness of the pollution flashover and the complex influencing factors make it difficult to be predicted. The objective of this paper is to study the mechanism of the discharging on insulator surfaces and design a the calculation method which derives flashover probability. By calculating the distorted electric field in the initial streamer discharge quantitatively and combining it with the equivalent circuit of the insulator surface, the initial discharge voltage is derived. By analyzing the change in power input and dissipation in the process of the arc discharge, we propose the criterion on arc development and extinction, and the critical flashover conductivity of the insulator is obtained. Based on the probability density function, the behavior of the factors on the critical flashover conductivity is described, and the probability of insulator pollution flashover is calculated under different environmental conditions. In the validation experiment, the measured initial discharge voltage and pollution flashover ratio are close to the calculated values. The methods proposed in this paper could be used in the quantitative calculation of the initial discharge voltage and the prevention of the pollution flashover on insulators.

A pulsed electric field (PEF) produces pasteurized liquid foods with fresh and nutritional properties. The treatment chamber is a crucial part of the PEF processing system where a high voltage is applied, producing an electric field to treat the liquid foods. The proper construction of the treatment chamber regulates the distribution of the electrical field inside the treatment zone. Mixing of liquid inside the treatment zone is an effective tool to overcome this heterogeneous effect. The coaxial treatment chamber offers a heterogeneous electric field and temperature distribution inside the treatment zone. A helical insulator inside the coaxial treatment chamber provides a mixing effect. In this research, a numerical simulation was done to measure the electric field in different geometries of treatment chambers at different flow rates. The simulation aimed to optimize the new coaxial treatment chamber design. The modelling findings showed homogeneous electrical field strength in the helical treatment chamber. This study provides new insights for industrial-scale setup using multiple helical chambers in a continuous flow PEF treatment.

Million tons of cellulosic paper have been used for insulating coils in oil-filled electrical power transformers, thereby assuring the electricity supply for our societies. The high working temperatures in transformers constantly degrade paper insulators throughout their service life of up to 40 years. We approached the structural changes in oil-immersed cellulosic paper samples upon thermal stress in a study that compared unbleached softwood Kraft paper used as insulator paper with pure cotton cellulose paper. The model experiments used a thermal treatment in transformer oil at 170 °C for up to 14 days. The samples were characterized by means of 13C CP/MAS NMR spectroscopy, mainly based on deconvolution of the C4 resonance. An automated, fast, and reproducible C4 resonance deconvolution employing the “Peak Analyzer” tool of OriginPro 2020 (OriginLab Corporation, USA) was developed and used to exploit 13C CP/MAS NMR spectroscopy for the characterization of thermally stressed paper samples. Our results show that thermally induced structural changes depend heavily on the composition of paper, that hornification and coalescence of fibrils take place, and that the allomorph composition of cellulose crystallites is altered under the given conditions. Graphical abstract

We present the catalytic performance of Pt-supported Cr2O3, and ZrO2 (semiconductors), and γ-Al2O3 (insulator) in CH4 oxidation under lean conditions. XPS analysis of the catalysts showed only Pt2+...

Fiber‐reinforced composites have been successfully used in a wide range of technological applications for decades. Fiber strength and modulus, chemical stability, and the interface bonding between the fiber and matrix are all factors that influence the mechanical performance of a fiber‐reinforced composite. Glass fiber‐reinforced polymeric composites (GFRP) were designed to be as strong as steel, stiffer than aluminum, and have a specific gravity of one‐fourth that of steel, thanks to its fiber composition and orientation. Glass fiber is a type of fiber‐reinforced plastic in which the reinforcing material is made of glass fiber. The load‐bearing insulator tubes are made of epoxy resin reinforced with electrical grade fiberglass using a wet filament‐winding technique. The compression insulators, the assembly's two primary structural elements, possess a unique non‐cylindrical form that offers them superior mechanical characteristics to typical overhead line insulators. The chapter introduces the application of GFRP in the power equipment at substation, power transmission, and distribution network.

This paper is an experimental study to evaluates the performance of Room Temperature Vulcanizing Silicone Rubber (RTV-SIR) coatings filled with carnauba wax and Alumina Trihydrate (ATH). The coatings were applied to glass insulators and subjected to pollution tests. The insulators performance was evaluated through the application of disruptive discharges and applied voltage under fog while monitoring the leakage current. The experimental results showed a reduction in leakage current and improved insulator performance for RTV-SIR coatings filled with carnauba wax under pollution conditions. The best results were achieved for coatings added with ATH and carnauba wax, indicated by the sample with the percentage composition of 75% RTV, 20% ATH and 5% carnauba wax.

The operation speed of dynamic random access memory devices has been increasing with respect to the evolution of electronic devices. This in turn has induced a decrease in the allowed time for the operation. Therefore, the effective capacitance degradation in which the capacitance gradually decreases with increasing frequency of applied ac voltage is a severe concern for decreasing capacitance during fast operation, in addition to inducing reliability degradation. Hence, in this article, the origin of capacitance degradation depending on operation frequency, also called “frequency dependence” of the capacitance, was revealed. By performing dc and ac nonlinearity analyses, the effect of defects, especially oxygen vacancies, on the electrical properties of metal-insulator-metal (MIM) capacitors was investigated. Eventually, the mechanism of frequency dependence related to oxygen vacancy in the insulator of the MIM capacitor was identified.

Due to the current status of water treatment system it is very difficult to produce fresh clean water without electricity. This research evaluated the intervention of titanium as heat absorber in the heat transfer analysis regarding the solar-based desalination system. The experiment was carried out in a double-slanted distillation unit designed to harness sunlight’s energy. The distillation unit contain a transparent glass shield, contaminated water inlet, treated water outlet, two treatment levels, heat absorber and insulator. Parameters monitors during the experiments included water treatment efficiency, productivity, distillation temperature and distillation rate. Variable included the heat absorber’s surface area with respect to the surface area of water in the chamber (10 to 90%). Experimental results were used to calculate water treatment efficiency using the Engineering Equation Solver (EES), which varied disproportionally with the size of Titanium heat absorber. The highest productivity was observed at 1.61 liter per day with a water treatment efficiency of 26.2%. The payback period of the solar-based distillation prototype was 5.5 years. The fastest distillation rate was monitored at 15:00 on average. Water’s level in distillation chamber and thermal conductivity of the insulator’s thermal conductivity inside both lower and higher still inside the unit have undesirable impact on performance. Wind speed promoted better heat transfer which resulted in an increase in distillation rate. Two numerical equations were developed for calculating distillation efficiency and productivity from input parameters such as operating time and heat absorber’s size. The prototype distillation unit demonstrated excellent results for converting salt water into fresh water.

This paper presents a solution for the regulation of electric field along the post insulator of 1 MV DC GIL for ITER neutral beam injector (NBI). To regulate the electric field distribution, a simulation model of the post insulator with surface nonlinear conductivity is developed. The actual working conditions of NBI GIL including a square wave voltage, a radiation environment as well as surface charge accumulation are considered. The results show that radiation will lead to a significant increase in the conductivity of SF6 gas, which makes the heteropolar charges from the SF6 gas domain dominate the surface charge. The tangential electric field on the insulator surface is seriously distorted by heteropolar charges. The post insulator with the design of surface nonlinear conductivity can effectively dissipate the surface charge and the tangential electric field along the insulator surface can be reduced by up to 46.5%. This paper aims to propose research methods and feasible means for the reasonable insulation design of NTER GIL to ensure the safe and stable operation of ITER.

A physical transient memristor synapse with self-rectifying and analogue switching behaviors based on Mo/MgO/AZO (Al2O3 2 wt %, ZnO 98 wt %)/W is presented. By modulating thickness of MgO layer, the device with 5 nm MgO insulator layer shows stable resistive switching memory with a rectification ratio up to 102, and precise tuning synaptic functions. Meanwhile, the formation of Schottky barrier and oxygen vacancy conductive filament is proposed to further explain self-rectifying and analogue switching behaviors. Additionally, the electrical characteristics of the Mo/MgO/AZO/W devices degraded after being immersed in deionized water (DI) for 3 min, which demonstrated the physically transient features successfully. The physical transient self-rectifying memristors have great potential for applications in secure neuromorphic computing systems, and bio-integrated electronics.

This review article presents an overview of the evolution of the field of insulator-based dielectrophoresis (iDEP); in particular, it focuses on insulator-based electrokinetic (iEK) systems stimulated with direct current and low-frequency(

In the present work, the structural, electronic and mechanical properties of Na2IrO3 and Li2IrO3 have been investigated by means of first principles calculations. The spin polarized generalized gradient approximation has been used for modeling exchange-correlation effects. The structural optimization of these compounds has been performed by using VASP-code, and the lattice parameters and magnetic moments have been calculated. From our calculation, it has been determined that X2IrO3 (X = Na, Li) compounds for both spin up and spin down states are indirect wide gap semiconductor in nature. Considering the spin states from the electronic band structure and density of the state (DOS) of the Na (Li)2IrO3 compounds, it has been identified that Eg=1.824 (2.315) eV for spin up and Eg=1.558 (2.019) eV for spin down. The second-order elastic constants have been calculated, and the other related quantities have also been estimated in the present work.

Hydrophobic cycloaliphatic epoxy resin (HCEP) insulators are a new generation of outdoor transmission line insulators with good application prospects. However, the HCEP has obvious curing internal stress due to the uneven internal temperature distribution. In this paper, the curing reaction of HCEP mixture is analyzed and a three-dimensional transient temperature field model of HCEP insulator is established. The internal temperature field of HCEP insulator during curing is analyzed for the first time. The results show that the curing reaction of HCEP mixture conforms to autocatalytic reaction. The structure of umbrella skirt causes the uneven temperature distribution inside HCEP insulator. Based on a surrogate model, it is found that thermal conductivity has a great influence on axial temperature distribution, while curing temperature plays a leading role in curing degree and temperature overshoot. The optimal curing temperature is found according to Pareto front. This paper is beneficial for the theoretical analysis and engineering guidance for manufacture of HCEP insulators.

A new vertical double-diffused metal oxide semiconductor field effect transistor (MOSFET) is presented based on the high- ${k}$ (Hk) MOSFET concept in this article with the step high- ${k}$ insulator, named as step Hk vertical double-diffused metal oxide semiconductor (VDMOS), to improve the electric field modulation effect. For step Hk VDMOS, the depletion is increased by the electric field modulation effect of step Hk insulator, which decreases the specific on-resistance of step Hk VDMOS compared to the conventional Hk VDMOS. The various thickness of the Hk insulator modulates the vertical electric field distribution in the drift region, which increases the breakdown voltage (BV) of the step Hk VDMOS. Meanwhile, an analytical model for novel step Hk VDMOS is obtained by solving the 2-D Poisson equation in an N-type drift region, and the 2-D Laplace equation in the step Hk region, which can reasonably explain the modulation effect of the step Hk region on the electric field distribution. The results show that the BV of the step Hk VDMOS is increased from 639 V of the conventional Hk VDMOS to 736 V with the same drift length of $42~\mu \text{m}$ . The theoretical results of the electrical characteristics are in good agreement with the results from numerical simulations.

INTRODUCCIÓN: Se aborda la problemática de confirmar resultados experimentales a través de un modelo matemático que permita predecir el comportamiento de variables térmicas, en un módulo de aprovechamiento solar para la generación de aire caliente. OBJETIVO: Desarrollar un modelo matemático que describa los procesos internos de intercambio de calor en un colector solar de placas planas. MÉTODO: La investigación se realiza bajo el doble enfoque: teórico y experimental. Se procede a la medición de los principales parámetros de funcionamiento del colector solar de placas planas, la elaboración del modelo matemático y la realización del balance térmico. RESULTADOS: Utilizando el recurso Guide de MATLAB, se programó una aplicación para la ejecución del modelo matemático, estableciéndose las constantes que corresponde a datos geométricos del módulo solar y del ducto, características del aislante y condiciones térmicas de radiación de los materiales utilizados. Finalmente, definidos los datos de entrada, se realizan las iteraciones correspondientes y se obtienen los resultados de cálculo, los ajustes de temperaturas se realizaron con una divergencia inferior al 1%. DISCUSIÓN Y CONCLUSIONES: El error promedio que representaría el desface entre el modelo propuesto respecto a los parámetros reales de funcionamiento, fue de un 2,55%, aceptables desde el punto de vista estadístico. Se confirman resultados de investigaciones precedentes en cuanto a buenos rendimientos para un caudal másico de 0,0204 kg/s. Se logró la evaluación de un módulo del aprovechamiento solar para la generación de aire caliente que posee enormes potencialidades para la calefacción de viviendas de la región sierra ecuatoriana.

—The polymer layer based on a nickel complex with salen-type ligand is proposed for protecting rechargeable lithium-ion batteries from overcharge. This polymer has a switchable resistance and can pass into the insulator state when the threshold potential is exceeded. This allows avoiding the development of side processes such as electrolyte decomposition on the cathode. The effect of the polymer layer was tested on model systems and on prototypes of lithium-ion batteries.

The two-dimensional (2D) structure often leads to unusual phenomena for the impact of confined mean free path of carrier scattering. As a quasi-2D layered material, AgCrSe2 has a liquid-like phonon behavior for its unstable Ag atoms at service temperature, leading to the promising candidate for thermoelectricity and fast ionic conductor. However, the inferior electronic performance constrains its application prospects as a functional semiconductor, which provides broad opportunity to tune its electric behaviors by defect chemistry. In this work, we revealed abundant electric transport behaviors of AgCrSe2 with different types of intrinsic defects. For example, the AgCrSe2 changes from Anderson insulator to metal when Se defects become prevailing and the magnetoresistance alters its sign depending on the relative ratio of Ag and Cr defects. Our results reported here can give salutary boosting on regulating the electric properties of ternary transition metal selenide by defect chemistry.

Seismic isolation is a system to reduce seismic energy acting on the bridge by adding an object so-called base insulator. The purpose of this study is to obtain a comparison of dimension, damping ratio, and the lower structure response designed as a ductile component with High Damping Rubber Bearings (HDRB) and Lead Rubber Bearings (LRB). This study uses CSI BRIDGE 21 computer program. Earthquake forces analysis uses dynamic analysis with response spectra as final evaluation for the performance of lead rubber bearing and high damping rubber bearings and the load characteristics for bridges is following SNI 1725: 2016 and bridge design for earthquake load is following SNI 2833: 2016. The bridge performance is expected to no longer rely merely on the dimensions and stiffness of the pillars in response to earthquake loads, but also on LRB or HDRB as a structural device on bridge support by increasing the effectiveness of pillar stiffness in providing damping energy during an earthquake.

The relationships between the microstructure and the dielectric properties of sol–gel prepared Y2O3 films with various Gd3+ doping were systematically investigated. Robust solution processed lanthanide films, (Y1−xGdx)2O3 (0 < x ≤ 0.5), are demonstrated as high-k gate insulators for low voltage-driven oxide thin film transistors and their optimized composition is presented. With the proper amount of Gd3+ doping, the corresponding thin film insulators exhibit low leakage current with increased dielectric constant. The resultant Zn–Sn–O/(Y, Gd)2O3 TFT exhibits enhanced performance, by a factor of 10.7 compared with TFTs using a SiO2 insulator, with a field-effect mobility of ~3.15 cm2V−1s−1 and an exceptionally low operating voltage

Research is devoted to investigation of properties of pulsed explosive emission cathodes for X-ray tubes. Three types of annular explosive emission cathodes were studied: metal ceramic with slits (of a comb-shaped kind), ring metal ceramic, and carbon ceramic. A pulsed high-voltage generator used in experiments is characterized with the following parameters: voltage pulse full-width at half-maximum is about 20 ns, pulse voltage amplitude is up to 150 kV, and pulse repetition rate is up to 200 Hz. The installation makes it possible to study demountable models of pulsed X-ray tubes of different designs. Current and voltage waveforms corresponding to different operation modes and rates of rise of X-ray tube anode voltage were analyzed. The obtained characteristics of explosive cathodes depend on the cathode’s material, the shape, and the supply voltage of the primary energy storage. The current pulse duration for the ring carbon-ceramic cathode is considerably lower than that for the other cathodes, although it generates a higher radiation dose rate.

Nowadays, end fitting corrosion reduces the mechanical strength and flashover voltage of insulators, forming a huge threat to high‐voltage direct current transmission lines. At present, the parameters of electrolytic corrosion inhibition measures are selected based on the premise of the constant annual corrosion rate. However, with the development of corrosion, corrosion products accumulate on the insulator surface, which may impact the corrosion rate. In order to clarify the influence of corrosion products, this work studied how corrosion products influence the corrosion rate from the corrosion phenomenon, corrosion current, feature and formation of corrosion products. The results showed that corrosion products of iron and zinc were excellent in adhesion on the insulator surface and could not be cleaned by rain, which was able to increase the corrosion rate. In future, in the selection of the quality of the zinc ring bonded on insulator fittings, there will be a demand to consider the influence of corrosion products on the corrosion rate.

Nanocrystal interfaces can strongly influence the optical and electrical properties and charging trapping phenomena observed on oxide nanocrystal ensembles. The well-defined shape and controllable size distributions of MgO nanocrystals are a convenient system for studying these effects. Therefore, in the present work focused on the effect of temperature on the optical and electrical properties of magnesium oxide (MgO) nanocrystals, together with the responsible atomic centers, the bulk MgO is a study based on the first principle functional density theory (DFT) using PBE-GGA approximations. The absorption coefficient shows that MgO shows good coverage in the ultraviolet range. The bulk MgO is a direct bandgap nanocrystal at G point in the Brillion Zone despite the temperature applied values. The temperature is applied to alter the bandgap pattern and closes the bandgap at a high temperature. The PDOS and imaginary part of the dielectric function further confirm the insulator properties of the observed bandgap. Our results show that the optical properties are affected by the inconsistent temperature manners despite the different temperatures given to the system. Our absorption curve confirms that the nanocrystal is a good candidate for ultraviolet device application with a significantly high reflectivity percentage.

Classically, the configuration of electrodes (conductors) is used as a means to determine AC-electroosmotic flow patterns. In this paper, we use the configuration of insulator materials to achieve AC-electroosmotic flow patterning in a novel approach. We apply AC electric fields between parallel electrodes situated on the top and bottom of a microfluidic channel and separated by an insulating material. Channels of various cross-sectional shapes (e.g. rectangular and parallelogram) were fabricated by shaping the insulating material between the electrodes. We found that vortex flow patterns are induced depending on the cross-sectional shape of the channel. A bell-shaped design with non-orthogonal corners gave rise to 2 vortices, whereas in a channel with a parallelogram shaped cross-section, only a single vortex was observed. The vortices were experimentally observed by analysing the 3D trajectories of fluorescent microparticles. From a theoretical analysis, we conclude that flow shaping is primarily caused by shaping the electrical field lines in the channel.

A new magnetic insulator Mn2MnSbO6 with a polar crystal structure and an ordered Mn2+ and Mn3+ arrangement was synthesized under a high pressure of 7.5 GPa and 1300 °C. The crystal structure of Mn2...

In recent years, glass fiber-reinforced epoxy composites have been proven to be a promising material for use in fabricating insulator core rods for high-voltage transmission lines. Composite insulator core rods are reportedly degrading during its application due to poor interfacial bonding, brittle fracture, stress corrosion cracking, water absorption, and decay-like fracture. These key factors have affected their mechanical and electrical insulation properties during application. However, this review summarizes the effects of glass fibers, such as E-glass and electrical corrosion resistance glass fiber on the corrosion, mechanical, and electrical properties of epoxy composites for composite insulator core rods. Further, the authors concluded the review with advancement, challenges, and recommendations for future improvement of epoxy composites as a mechanical load-bearing and insulation component material in high-voltage composite insulators. As such, the review offers an intuition into the advancement and selection of glass fiber-reinforced epoxy composite materials for core rods. More so, the review will also give way for further research on insulator core rods development for high-voltage transmission lines.

Carbon nanotube field-effect transistors (CNTFETs) with optimized oxide thicknesses have been proposed. The optimum oxide thickness that provides the maximum current ratio (on/off ratio) has been calculated for each design. The effect of oxide thickness on the on/off ratio has been investigated by changing its value as the independent variable and calculating on state and off state currents. PSO algorithm has been used to find the exact optimum value of the oxide thickness with the objective of having a maximum current ratio that is one of the most important parameters in switching applications. The optimum insulator thickness is calculated for CNTFETs with different chiral vectors, insulator types, channel lengths and source/drain doping levels. For further study of the CNTFETs, performance parameters such as cutoff frequency and transconductance of the devices have also been calculated and studied. The results of the paper show that the CNTFET designers should select the oxide thickness very carefully not only based on reported values in other works. Each design requires its own optimum oxide thickness which provides the maximum on/off current ratio only for that design.

The failure of an insulator may compromise the safety of the entire power transmission system. Therefore, insulator defect detection is vital for the safe operation of power systems. However, insulator defects in an insulator image may have varying sizes, and several currently available methods do not have satisfactory detection accuracy for small defects. To address this issue, we propose an improved detection network for small insulator defects with a batch normalization convolutional block attention module (BN-CBAM) and a feature fusion module. The BN-CBAM is designed to better exploit channel information and enhance the effect of different channels on the feature map. In addition, we propose a feature fusion module that fuses multi-scale features from different layers to improve small object detection performance. Moreover, to address the scarcity of aerial images, a data augmentation method based on the fusion of the target segment and background is introduced. Experiments demonstrate that the proposed method achieves better small insulator defect detection performance than other state-of-the-art approaches. In addition, data augmentation methods enrich sample diversity and enhance the generalizability of the network.

The ultrafast concentration of electromagnetic energy in nanoscale volumes is one of the key features of optical nanoantennas illuminated at their surface plasmon resonances. Here, we drive the insulator to metal phase transition in vanadium dioxide (VO2) using a laser-induced pumping effect obtained by positioning a single gold nanoantenna in proximity to a VO2 thermochromic material. We explore how the geometry of the single nanoantenna affects the size and permittivity of the nanometer-scale VO2 regions featuring phase transition under different pumping conditions. The results reveal that a higher VO2 phase transition effect is obtained for pumping of the longitudinal or transversal localized surface plasmon depending on the antenna length. This characterization is of paramount importance since the single nanoantennas are the building blocks of many plasmonic nanosystems. Finally, we demonstrate the picosecond dynamics of the VO2 phase transition characterizing this system, useful for the realization of fast nano-switches. Our work shows that it is possible to miniaturize the hybrid plasmonic-VO2 system down to the single-antenna level, still maintaining a controllable behavior, fast picosecond dynamics, and the features characterizing its optical and thermal response., LB, NZ, and JA acknowledge financial support from Spanish MICIN (DOI 10.13039/501100004837) through Project Ref. No. PID2019-107432GB-I00, from the Department of Education of the Basque Government under project IT1164-19 and the Department of Industry of the Basque Government under Elkartek project KK-2018/0000. OM and BC acknowledge support from EPSRC (DOI 10.13039/501100000266) through grants EP/J016918/1 and EP/M009122/1.

In this paper, we pay the main attention to the topological insulators invariant under time reversal. Such systems are characterized by having a wide energy gap stable under small deformations. An example of such systems is provided by the quantum spin Hall insulator. It has a nontrivial topological $$\mathbb Z_2$$ -invariant introduced by Kane and Mele.