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This study analyzes the optimization of Extra High Voltage (EHV) transmission line design parameters by Uttar Pradesh Power Corporation Limited (UPPCL) in India to improve power grid efficiency and reliability. UPPCL reduced insulation specifications for 400 kV lines from 27 to 21 disc insulators and decreased live metal clearance from 2600 to 2400 mm, resulting in 7–9% cost savings per line and reduced right-of-way requirements. While initial test lines performed satisfactorily for over 5 years, longer lines experienced operational challenges related to insulator quality, bird activity, and design margins. Tripping issues emerged during adverse weather conditions, particularly in foggy winter periods. Root cause analysis revealed the need for stringent insulator quality control, regular cleaning to mitigate bird dropping contamination, and potential corona ring design improvements. This case study demonstrates how targeted EHV transmission line optimization can yield significant cost and environmental benefits, while highlighting the importance of balancing economic gains with reliability and safety considerations. The findings provide valuable insights for future EHV transmission line designs and upgrades across India's power grid. [ABSTRACT FROM AUTHOR]

Topologically associating domain (TAD) boundaries are the flanking edges of TADs, also known as insulated neighborhoods, within the 3D structure of genomes. A prominent feature of TAD boundaries in mammalian genomes is the enrichment of clustered CTCF sites often with mixed orientations, which can either block or facilitate enhancer–promoter (E‐P) interactions within or across distinct TADs, respectively. We will discuss recent progress in the understanding of fundamental organizing principles of the clustered CTCF insulator codes at TAD boundaries. Specifically, both inward‐ and outward‐oriented CTCF sites function as topological chromatin insulators by asymmetrically blocking improper TAD‐boundary‐crossing cohesin loop extrusion. In addition, boundary stacking and enhancer clustering facilitate long‐distance E‐P interactions across multiple TADs. Finally, we provide a unified mechanism for RNA‐mediated TAD boundary function via R‐loop formation for both insulation and facilitation. This mechanism of TAD boundary formation and insulation has interesting implications not only on how the 3D genome folds in the Euclidean nuclear space but also on how the specificity of E‐P interactions is developmentally regulated. [ABSTRACT FROM AUTHOR]

Aiming at the problems of a large volume, slow processing speed, and difficult deployment in the edge terminal, this paper proposes a lightweight insulator detection algorithm based on an improved SSD. Firstly, the original feature extraction network VGG-16 is replaced by a lightweight Ghost Module network to initially achieve the lightweight model. A Feature Pyramid structure and Feature Pyramid Network (FPN+PAN) are integrated into the Neck part and a Simplified Spatial Pyramid Pooling Fast (SimSPPF) module is introduced to realize the integration of local features and global features. Secondly, multiple Spatial and Channel Squeeze-and-Excitation (scSE) attention mechanisms are introduced in the Neck part to make the model pay more attention to the channels containing important feature information. The original six detection heads are reduced to four to improve the inference speed of the network. In order to improve the recognition performance of occluded and overlapping targets, DIoU-NMS was used to replace the original non-maximum suppression (NMS). Furthermore, the channel pruning strategy is used to reduce the unimportant weight matrix of the model, and the knowledge distillation strategy is used to fine-adjust the network model after pruning, so as to ensure the detection accuracy. The experimental results show that the parameter number of the proposed model is reduced from 26.15 M to 0.61 M, the computational load is reduced from 118.95 G to 1.49 G, and the mAP is increased from 96.8% to 98%. Compared with other models, the proposed model not only guarantees the detection accuracy of the algorithm, but also greatly reduces the model volume, which provides support for the realization of visible light insulator target detection based on edge intelligence. [ABSTRACT FROM AUTHOR]

Ceramic and glass insulators as the first generation of insulators are often affected by flashover disturbance during operation. Ceramic insulators coated with semiconducting glaze (SCG) material are then proposed to improve the insulation performance due to warmer surface characteristics that can trigger evaporation on the surface. In this paper, a comparison of insulation performances of semiconducting glaze, ceramic, and glass insulators is discussed from both electrical and non-electrical aspects under various conditions. This comparison aims to distinguish the leakage current characteristics of each insulator during operation. Leakage current tests are conducted to obtain leakage current characteristics of each insulator under artificial conditions of no fog, clean fog, and salt fog. Furthermore, pollutants that are a mixture of NaCl (as equivalent salt deposit density (ESDD)) and kaolin (as non-soluble deposit density (NSDD)) are sprayed onto the insulator surface to see how the pollutant affects the leakage current characteristics of each insulator. The properties of measured leakage current waves are then analyzed, including the waveform, magnitude, and harmonic components. In addition, the non-electrical tests consist of hydrophobicity tests and thermal tests. In the hydrophobicity test, the contact angle formed by a water droplet on the insulator surface is measured, and in the thermal test, temperature differences on the insulator surface before and after voltage applications are compared. The experiment results show that the SCG insulator has a larger leakage current than the other insulators, while the leakage current magnitude of the ceramic and glass insulators is similar. The surface temperature of the SCG insulator is also higher than that of the other insulators due to a larger leakage current. Additionally, the SCG insulator shows better hydrophobicity compared to the other insulators, where all types of insulators show decreased contact angle when pollutants are given. [ABSTRACT FROM AUTHOR]

Outdoor, real-time, and accurate detection of insulator defect locations can effectively avoid the occurrence of power grid security accidents. This paper proposes an improved GhostNet-YOLOv5s algorithm based on GhostNet and YOLOv5 models. First, the backbone feature extraction network of YOLOv5 was reconstructed with the lightweight GhostNet module to reduce the number of parameters and floating point operations of the model, so as to achieve the purpose of being lightweight. Then, a 160 × 160 feature layer was added to the YOLOv5 network to extract more feature information of small targets and fuzzy targets. In addition, the introduction of lightweight GSConv convolution in the neck network further reduced the computing cost of the entire network. Finally, Focal-EIoU was introduced to optimize the CIoU bounding box regression loss function in the original algorithm to improve the convergence speed and target location accuracy of the model. The experimental results show that the parameter number, computation amount, and model size of the GhostNet-YOLOv5s model are reduced by 40%, 25%, and 36%, respectively, compared with the unimproved YOLOv5s model. The proposed method not only ensures the precision of insulator defect detection, but also greatly decreases the complexity of the model. Therefore, the GhostNet-YOLOv5s algorithm can meet the requirements of real-time detection in complex outdoor environments. [ABSTRACT FROM AUTHOR]

Transvection is a phenomenon of interallelic communication in which enhancers can activate a specific promoter located on a homologous chromosome. Insulators play a significant role in ensuring functional interactions between enhancers and promoters. In the presented work, we created a model where two or three copies of the insulator are located next to enhancers and promoters localized on homologous chromosomes. Using the Su(Hw) insulator as a model, we showed that the functional interaction between a pair of insulators promotes enhancer–promoter trans-interactions. The interaction between the three insulators, on the contrary, can lead to the formation of chromatin loops that sterically hinder the full enhancer–promoter interaction. The results of the work suggest the participation of insulators in the regulation of homologous chromosome pairing and in communication between distant genomic loci. [ABSTRACT FROM AUTHOR]

Currently, the use of deep learning technologies for detecting defects in transmission line insulators based on images obtained through unmanned aerial vehicle inspection simultaneously presents the problems of insufficient detection accuracy and speed. Therefore, this study first introduced the bidirectional feature pyramid network (BiFPN) module into YOLOv5 to achieve high detection speed as well as enable the combination of image features at different scales, enhance information representation, and allow accurate detection of insulator defect at different scales. Subsequently, the BiFPN module and simple parameter-free attention module (SimAM) were combined to improve the feature representation ability and object detection accuracy. The SimAM also enabled fusion of features at multiple scales, further improving the insulator defect detection performance. Finally, multiple experimental controls were designed to verify the effectiveness and efficiency of the proposed model. The experimental results obtained using self-made datasets show that the combined BiFPN and SimAM model (i.e., the improved BaS-YOLOv5 model) performs better than the original YOLOv5 model; the precision, recall, average precision and F1 score increased by 6.2%, 5%, 5.9%, and 6%, respectively. Therefore, BaS-YOLOv5 substantially improves detection accuracy while maintaining a high detection speed, meeting the requirements for real-time insulator defect detection. [ABSTRACT FROM AUTHOR]

Insulators are vital components used in electrical transmission lines. It's crucial to keep their production cost low since they are widely used in electricity transmission. Instead of expensive alumina-based insulators, we can make cheaper ones using clay and bauxite found in nature. Adding more alumina makes them stronger, which is important for high voltage transmission. This paper aims to study the production process of bauxite-based insulators. We examined the insulators' structure using SEM images and EDAX spectrum analysis to see their formations, porosity ratio, and density. This research helps us learn more about these insulators and how they can be used effectively for high voltage transmission lines. [ABSTRACT FROM AUTHOR]

In the process of power system inspection, manual inspection is difficult and poses safety hazards. The unmanned aerial vehicle platform equipped with intelligent algorithms has a promising prospect of replacing manual insulator detection methods. In response to the shortcomings of slow speed and low accuracy in the detection process of insulator defect targets, an improved YOLOv5 insulator defect fault detection method integrating attention mechanism was proposed. This method integrates the SE attention module and CBAM attention module in the YOLOv5s network, and combines the SE attention module with the C3 module in the network structure to enhance the network’s feature extraction ability. The construction of the self-built insulator dataset was completed through relevant image processing methods. The K-means + + clustering algorithm was used to construct the prior frame of the self-built dataset, and the Mosaic9 data augmentation strategy was introduced, effectively solving the problem of insufficient training data and difficulty in ensuring training effectiveness. Experimental verification shows that the improved detection method improves the accuracy of insulator detection by 9. 7% without affecting the detection time, which has certain reference significance for power system inspection methods. [ABSTRACT FROM AUTHOR]

Chromatin architecture is critical for the temporal and tissue-specific activation of genes that determine eukaryotic development. The functional interaction between enhancers and promoters is controlled by insulators and tethering elements that support specific long-distance interactions. However, the mechanisms of the formation and maintenance of long-range interactions between genome regulatory elements remain poorly understood, primarily due to the lack of convenient model systems. Drosophila became the first model organism in which architectural proteins that determine the activity of insulators were described. In Drosophila, one of the best-studied DNA-binding architectural proteins, Su(Hw), forms a complex with Mod(mdg4)-67.2 and CP190 proteins. Using a combination of CRISPR/Cas9 genome editing and attP-dependent integration technologies, we created a model system in which the promoters and enhancers of two reporter genes are separated by 28 kb. In this case, enhancers effectively stimulate reporter gene promoters in cis and trans only in the presence of artificial Su(Hw) binding sites (SBS), in both constructs. The expression of the mutant Su(Hw) protein, which cannot interact with CP190, and the mutation inactivating Mod(mdg4)-67.2, lead to the complete loss or significant weakening of enhancer–promoter interactions, respectively. The results indicate that the new model system effectively identifies the role of individual subunits of architectural protein complexes in forming and maintaining specific long-distance interactions in the D. melanogaster model. [ABSTRACT FROM AUTHOR]

In the past few years, considerable focus has been directed toward the employment of appropriate coatings with the intention of mitigating imperfections brought about by various factors including UV radiation, humidity, and particulate matter within the insulation framework. Employing an appropriate polymer coating to preserve the characteristics of insulating materials can prove to be an effective remedy within this domain. Polymer composites have emerged as viable substitutes for ceramic insulation, owing to their distinctive characteristics such as lightweight composition, hydrophobic surface properties, thermal and dielectric attributes, as well as superior resistance to vandalism. Typically, polymer insulation comprises two primary components: the insulating core, commonly composed of materials like fiber or epoxy, and the secondary part, which incorporates elastomeric substances such as ethylene propylene diene monomer (EPDM) and Polydimethylsiloxane (PDMS). The use of silicone contributes to the prolonged retention of surface properties, primarily due to the chemical stability inherent in the polymer chains. Silicone-based insulators, characterized by their low surface energy and resulting hydrophobic surface, prove to be more suitable in wet conditions. However, these materials are susceptible to degradation from environmental factors such as temperature, humidity, and Ultraviolet (UV) radiation. An inherent challenge with composite insulators lies in their aging process. Various strategies are employed to enhance polymer properties, involving mixing, composition adjustments, and the incorporation of diverse additives to improve specific material characteristics. This discussion outlines factors influencing insulator efficiency and explores various methods for enhancing the performance of polymer insulators, with a focus on hydrophobic and superhydrophobic surfaces. [ABSTRACT FROM AUTHOR]

In this work, a study on a cap and pin insulator (1512L) is proposed to evaluate the distribution of the electric field and the potential along the insulator under different conditions. A computational and experimental study for the examination of a real insulators model is assessed. Tests on contaminated insulators in the laboratory under the suggested conditions have been carried out. Finite element methods (FEM) have been employed in the numerical analysis to assess the electrical properties of the insulator under the suggested contamination profiles, including potential and electric field. The study proposed in this paper provides an effective and practical tool for analysis and enhance the dielectric properties of the studied insulator. [ABSTRACT FROM AUTHOR]

Insulators are crucial insulation components and structural supports in power grids, playing a vital role in the transmission lines. Due to temperature fluctuations, internal stress, or damage from hail, insulators are prone to injury. Automatic detection of damaged insulators faces challenges such as diverse types, small defect targets, and complex backgrounds and shapes. Most research for detecting insulator defects has focused on a single defect type or a specific material. However, the insulators in the grid's transmission lines have different colors and materials. Various insulator defects coexist, and the existing methods have difficulty meeting the practical application requirements. Current methods suffer from low detection accuracy and mAP0.5 cannot meet application requirements. This paper proposes an improved you only look once version 7 (YOLOv7) model for multi-type insulator defect detection. First, our model replaces the spatial pyramid pooling cross stage partial network (SPPCSPC) module with the receptive filed block (RFB) module to enhance the network's feature extraction capability. Second, a coordinate attention (CA) mechanism is introduced into the head part to enhance the network's feature representation ability and to improve detection accuracy. Third, a wise intersection over union (WIoU) loss function is employed to address the low-quality samples hindering model generalization during training, thereby improving the model's overall performance. The experimental results indicate that the proposed model exhibits enhancements across various performance metrics. Specifically, there is a 1.6% advancement in mAP_0.5, a corresponding 1.6% enhancement in mAP_0.5:0.95, a 1.3% elevation in precision, and a 1% increase in recall. Moreover, the model achieves parameter reduction by 3.2 million, leading to a decrease of 2.5 GFLOPS in computational cost. Notably, there is also an improvement of 2.81 milliseconds in single-image detection speed. This improved model can detect insulator defects for diverse materials, color insulators, and partial damage shapes in complex backgrounds. [ABSTRACT FROM AUTHOR]

We analyze the propagation of two-dimensional dispersive and relativistic wavepackets localized in the vicinity of the zero level set T of a slowly varying domain wall modeling the interface separating two insulating media. We propose a semiclassical oscillatory representation of the propagating wavepackets and provide an estimate of their accuracy in appropriate energy norms. We describe the propagation of relativistic modes along T and analyze dispersive modes by a stationary phase method. In the absence of turning points, we show that arbitrary smooth localized initial conditions may be represented as a superposition of such wavepackets. In the presence of turning points, the results apply only for sufficiently high-frequency wavepackets. The theory finds applications for both Dirac systems of equations modeling topologically nontrivial systems as well as Klein--Gordon equations, which are topologically trivial. [ABSTRACT FROM AUTHOR]

Regardless of the environment, the power system network must be continuously operational. Current spacer failures of Gas Insulated Busduct (GIB) have been noted as a result of a number of manufacturing and switching faults, including delamination, protrusion, depression, gap, etc. These defects have a severe negative effect on the insulator's surface, which de-energises the gas-insulated busduct device and causes a significant financial loss. For the purpose of studying the electric stress at the Triple Junction, a Functionally Graded Material (FGM) spacer is built for a three phase GIB with protrusion irregularity in this work. The stress is reduced by inserting metal inserts at the end of the zero potential. Functionally graded materials are spatially distributed with numerous filler materials to achieve homogeneous electric field stress by doping them with various permittivity values. The spacer used in the simulation is made to withstand a range of voltages as well as varied FGM gradings. Grading's impact on electric field stress is identified and further diminished with the addition of the MI to the FGM insulator. The outcomes are discussed and analysed to demonstrate how well the proposed spacer works. [ABSTRACT FROM AUTHOR]

The transcriptome data of skin cells from domestic cats with brown, orange, and white coats were analyzed using a public database to investigate the possible relationship between coat color‐related gene expression and squamous cell carcinoma risk, as well as the mechanism of deafness in white cats. We found that the ratio of the expression level of genes suppressing squamous cell carcinoma to that of genes promoting squamous cell carcinoma might be considerably lower than the theoretical estimation in skin cells with orange and white coats in white‐spotted cat. We also found the possibility of the frequent production of KIT lacking the first exon (d1KIT) in skin cells with white coats, and d1KIT production exhibited a substantial negative correlation with the expression of SOX10, which is essential for melanocyte formation and adjustment of hearing function. Additionally, the production of d1KIT was expected to be due to the insulating activity of the feline endogenous retrovirus 1 (FERV1) LTR in the first intron of KIT by its CTCF binding sequence repeat. These results contribute to basic veterinary research to understand the relationship between cat skin coat and disease risk, as well as the underlying mechanism. [ABSTRACT FROM AUTHOR]

Drosophila CP190 and CP60 are transcription factors that are associated with centrosomes during mitosis. CP190 is an essential transcription factor and preferentially binds to housekeeping gene promoters and insulators through interactions with architectural proteins, including Su(Hw) and dCTCF. CP60 belongs to a family of transcription factors that contain the N-terminal MADF domain and the C-terminal BESS domain, which is characterized by the ability to homodimerize. In this study, we show that the conserved CP60 region adjacent to MADF is responsible for interacting with CP190. In contrast to the well-characterized MADF-BESS transcriptional activator Adf-1, CP60 is recruited to most chromatin sites through its interaction with CP190, and the MADF domain is likely involved in protein–protein interactions but not in DNA binding. The deletion of the Map60 gene showed that CP60 is not an essential protein, despite the strong and ubiquitous expression of CP60 at all stages of Drosophila development. Although CP60 is a stable component of the Su(Hw) insulator complex, the inactivation of CP60 does not affect the enhancer-blocking activity of the Su(Hw)-dependent gypsy insulator. Overall, our results indicate that CP60 has an important but redundant function in transcriptional regulation as a partner of the CP190 protein. [ABSTRACT FROM AUTHOR]

Acoustic inspection is a valuable technique that can detect early stage defects in equipment, thereby facilitating predictive maintenance. In recent times, ultrasonic sensors have made detecting partial discharges through acoustic sensing increasingly feasible. However, interpreting the acoustic signals can pose challenges, as it requires extensive expertise and knowledge of equipment configuration. To address this issue, a technique based on zero-crossing rate and fundamental frequency estimation has been proposed to standardize insulator diagnosis. In an experiment involving a database of 72 raw acoustic signals with frequencies ranging from 0 to 128 kHz, various types of pollution and defects were introduced to a chain of insulators. By employing the proposed technique, the occurrence of partial discharges can be detected and classified according to type, such as corona or surface discharges. This advanced approach to diagnosis simplifies the process while providing valuable insights into the severity of observed phenomena in the field. [ABSTRACT FROM AUTHOR]

Railway system insulators are affected by pollution, altitude, and other environmental situations during operation, which causes reduced electrical performance or even flashover accidents. These factors threaten the safety of railway operations in high-altitude areas. However, the natural contamination characteristics of a railroad in a plateau area is still unclear. In this study, a natural pollution accumulation test for railway insulators in a high-altitude area was carried out, and the distribution rules of nonsoluble deposit density (NSDD), equivalent salt deposit density (ESDD), NSDD/ESDD ratio, and nonuniformity (T/B) of the pollution distribution of the tested insulators were calculated. Meanwhile, the chemical compositions of the pollution from different test sites were analyzed. The differences of pollution accumulation between railway insulators and suspended insulators of a power system and the influencing factors were compared and analyzed by combining with a numerical simulation. The results show that the pollution level of railroad insulators is mainly distributed in level b and above. A pollution sample is mainly composed of sodium chloride, while the NSDD/ESDD ratio of pollution is mostly distributed from 0 to 5, with T/B value ranges from 1/0.62 to 1/1.76. The amount of insulator contamination is influenced by the location inside and outside the tunnel. Additionally, the pollution amount is influenced by the structure and type of insulators. Finally, this paper studies the creepage distance and structural height required by railway insulators in a plateau area according to the natural pollution accumulation characteristics of railway insulators, which can provide a reference for a railway electrical external insulation configuration in a high-altitude area. [ABSTRACT FROM AUTHOR]

The world is seeking alternative ways of renewable energy to fulfill the everyday growing energy demands and to reduce reliance on traditional carbon-based fuels. The scientific communities and researchers have started looking Infra-Red (IR) as an alternative source of renewable energy. There is abundant IR energy available from the waste heat sources. Harvesting this IR energy can be a promising solution in addressing the clean energy demand. The waste heat can be treated as high oscillating electromagnetic (EM) waves, having the highest intensity at 10.6 µm (28.3 THz). The IR energy harvesting can be achieved by using a device typically known as "Rectenna", which is an integration of nanoantenna and high frequency diode. The bowtie antenna which has ease in fabrication and integration simplicity is one of the ideal candidates for nanoantenna in collecting the waves. Furthermore, for energy harvesting applications, it is desired to have a passive rectification. The metal–Insulator-metal (M1I1M2) which works on the principle of electron tunneling, are one of the few candidates for rectenna system. In this paper, a different combination of metal arms has been explored for high frequency (28.3 THz) operations. The metal with different work function has been simulated to have the best electron tunneling and higher rectification. Also, in the this work we have studied the effect of substrate on the antenna performance at 28.3 THz. According to author best knowledge, this is the first comprehensive and systematic study on antenna arms for the rectenna system used in energy harvesting applications at 28.3 THz. [ABSTRACT FROM AUTHOR]

At this stage, the inspection of transmission lines is dominated by UAV inspection. Insulators, as essential equipment for transmission line equipment, are susceptible to various factors during UAV detection, and their detection results often lead to leakages and false detection. Combining deep learning detection algorithms with the UAV transmission line inspection system can effectively solve the current sensing problem. To improve the recognition accuracy of insulator detection, the MS-COCO pre-training strategy that combines the FPN module with a cascading R-CNN algorithm based on the ResNeXt-101 network is proposed. The purpose of this paper is to systematically and comprehensively analyze mainstream isolator detection algorithms at the current stage and to verify the effectiveness of the improved Cascade R-CNN X101 model by combining the mAP (mean Average Precision) value and other related evaluation indices. Compared with Faster R-CNN, Retina Net, and other detection algorithms, the model is highly accurate and can effectively deal with the false detection, leakage, and non-recognition of the environment in online special detection. The research in this paper provides a new idea for intelligent fault detection of transmission line insulators and has some reference value for engineering applications. [ABSTRACT FROM AUTHOR]

In higher eukaryotes, distance enhancer-promoter interactions are organized by topologically associated domains, tethering elements, and chromatin insulators/boundaries. While insulators/boundaries play a central role in chromosome organization, the mechanisms regulating their functions are largely unknown. In the studies reported here, we have taken advantage of the well-characterized Drosophila bithorax complex (BX-C) to study one potential mechanism for controlling boundary function. The regulatory domains of BX-C are flanked by boundaries, which block crosstalk with their neighboring domains and also support long-distance interactions between the regulatory domains and their target gene. As many lncRNAs have been found in BX-C, we asked whether readthrough transcription (RT) can impact boundary function. For this purpose, we took advantage of two BX-C boundary replacement platforms, Fab-7attP50 and F2attP, in which the Fab-7 and Fub boundaries, respectively, are deleted and replaced with an attP site. We introduced boundary elements, promoters, and polyadenylation signals arranged in different combinations and then assayed for boundary function. Our results show that RT can interfere with boundary activity. Since lncRNAs represent a significant fraction of Pol II transcripts in multicellular eukaryotes, it is therefore possible that RT may be a widely used mechanism to alter boundary function and regulation of gene expression. [ABSTRACT FROM AUTHOR]

Operation accidents caused by deteriorated insulators occur from time to time, which poses a direct threat to the safe and stable operation of transmission lines. Much research has been done at home and abroad on the degradation mechanism of deteriorated insulators, the electric field distribution characteristics of insulator strings and the influence of deteriorated insulators on the space electric field, but there is little research on the influence of three-phase electrification on the space electric field of insulator strings. Therefore, this paper studies the simulation and detection of electric field distribution of deteriorated insulators in three-phase transmission lines. First, the difference between three-phase electrification and single-phase electrification on the space electric field of insulator strings is simulated and analyzed, and the influence of deteriorated insulators on the space electric field distribution of insulator strings under three-phase electrification is studied. Second, based on simulation results, a detection method for deteriorated insulators in three-phase overhead trans-mission lines is proposed, and a non-contact space electric field measurement device based on Unmanned Aerial Vehicle (UAV) is developed. Finally, a Unmanned Aerial Vehicle inspection system is used to test the transmission lines in combination with an electric power department, and the simulation results and the effectiveness of the proposed detection method are verified. Results show the electric field distribution of insulator strings is obviously different between three-phase electrification and single-phase electrification, and when the detection distance is 300 mm, the proposed detection method and device can effectively identify deteriorated insulators in three-phase transmission lines. [ABSTRACT FROM AUTHOR]

The condensation mechanism of the insulators' surface, increase the surface electrical conductivity. The electrical conductivity of the insulator creates a high level of leakage current and causes the failure. Difference between the dew point and the surface temperature of the insulator which occur due to radiative cooling mechanism, is the major reason of the moisture condensation on the polluted insulator surface. To compensate for the temperature difference, carbon nanotubes (CNTs) are being added to the silicone rubber housing material. The main idea of this research is based on generating joule heating by reducing the surface resistance of high voltage insulators. For this purpose, a developed model based on Halpin–Tsai formulation for tensile modulus of nanocomposites is joined with the conventional power-law model for the effective electrical conductivity of silicone rubber matrix carbon nanotube composite (SMCNT). SMCNT samples are prepared with the addition of various CNT volume fractions to high temperature vulcanizing (HTV) silicone rubber by melt-blending method. The developed model reveals that the high fraction of thinner and longer CNT, thicker interphase, higher concentration of percolated CNT, lower waviness of CNT, and higher conductivity of CNT can make a higher effective conductivity for SMCNT. [ABSTRACT FROM AUTHOR]

With the increasing world population, energy production and distribution has a very important place today. Insulators are one of the elements that play the most active role in the reliability and continuity of electrical transmission and distribution lines. Faults from insulators account for the highest rate of power system failures. Icing and subsequent insulator failures cause flashover on the insulator surface in areas where intense winter conditions occur, leading to power outages and major socioeconomic consequences. Leakage currents are directly related to the surface properties of ice-coated insulators. In this study, the surface of insulators made of different materials were iced in a laboratory environment and leakage currents were studied by applying an alternating voltage with a network frequency to the insulators according to the degree of icing. Data were obtained with the help of LabVIEW program and leakage currents of porcelain, glass and silicon insulators were compared. The relationship between the leakage current was established by measuring the ambient temperature and humidity values of the insulator. [ABSTRACT FROM AUTHOR]

Insulators are architectural elements implicated in the organization of higher-order chromatin structures and transcriptional regulation. However, it is still unknown how insulators contribute to Drosophila telomere maintenance. Although the Drosophila telomeric retrotransposons HeT-A and TART occupy a common genomic niche, they are regulated independently. TART elements are believed to provide reverse transcriptase activity, whereas HeT-A transcripts serve as a template for telomere elongation. Here, we report that insulator complexes associate with TART and contribute to its transcriptional regulation in the Drosophila germline. Chromatin immunoprecipitation revealed that the insulator complex containing BEAF32, Chriz, and DREF proteins occupy the TART promoter. BEAF32 depletion causes derepression and chromatin changes at TART in ovaries. Moreover, an expansion of TART copy number was observed in the genome of the BEAF32 mutant strain. BEAF32 localizes between the TART enhancer and promoter, suggesting that it blocks enhancer-promoter interactions. Our study found that TART repression is released in the germ cysts as a result of the normal reduction of BEAF32 expression at this developmental stage. We suggest that coordinated expression of telomeric repeats during development underlies telomere elongation control. [ABSTRACT FROM AUTHOR]

In the application process of insulator defect detection model, it is necessary to detect a variety of target domain images. However, due to the different distribution of images in different target domains, it is difficult for the defect detection model trained in the source domain to achieve good detection results in different target domains. Aiming at the problem of low generalization of defect detection models, a transmission line defect detection method based on domain knowledge transfer was proposed. First, a new feature fusion method was adopted to improve the feature extraction ability of defective targets. Then image-and instance-level-based domain classifiers were implemented through adversarial training, and domain transfer was realized at image and target levels. A region-level domain classifier was introduced into the network, which further realized the alignment of the source and target domains at the region level. The experimental results show that the model can alleviate the problem of poor detection effect caused by the imbalance of image distribution in different domains, and achieve better defect detection effect compared with other target detection methods. [ABSTRACT FROM AUTHOR]

For high electron mobility transistors (HEMTs) power transistors based on AlGaN/GaN heterojunction, p-GaN gate has been the gate topology commonly used to deplete the two dimensional electron gas (2-DEG) and achieve a normally-OFF behavior. But fully recessed MIS gate GaN power transistors or MOSc-HEMTs have gained interest as normally-OFF HEMTs thanks to the wider voltage swing and reduced gate leakage current when compared to p-GaN gate HEMTs. However the mandatory AlGaN barrier etching to deplete the 2-DEG combined with the nature of the dielectric/GaN interface generates etching-related defects, traps, and roughness. As a consequence, the threshold voltage (VTH) can be unstable, and the electron mobility is reduced, which presents a challenge for the integration of a fully recessed MIS gate. Recent developments have been studied to solve this challenge. In this paper, we discuss developments in gate recess with low impact etching and atomic layer etching (ALE) alongside surface treatments such as wet cleaning, thermal or plasma treatment, all in the scope of having a surface close to pristine. Finally, different interfacial layers, such as AlN, and alternative dielectrics investigated to optimize the dielectric/GaN interface are presented. [ABSTRACT FROM AUTHOR]

The cohesin complex has a range of crucial functions in the cell. Cohesin is essential for mediating chromatid cohesion during mitosis, for repair of double‐strand DNA breaks, and for control of gene transcription. This last function has been the subject of intense research ever since the discovery of cohesin's role in the long‐range regulation of the cut gene in Drosophila. Subsequent research showed that the expression of some genes is exquisitely sensitive to cohesin depletion, while others remain relatively unperturbed. Sensitivity to cohesin depletion is also remarkably cell type‐ and/or condition‐specific. The relatively recent discovery that cohesin is integral to forming chromatin loops via loop extrusion should explain much of cohesin's gene regulatory properties, but surprisingly, loop extrusion has failed to identify a 'one size fits all' mechanism for how cohesin controls gene expression. This review will illustrate how early examples of cohesin‐dependent gene expression integrate with later work on cohesin's role in genome organization to explain mechanisms by which cohesin regulates gene expression. [ABSTRACT FROM AUTHOR]

The measurement of the thermal conductivity of the sawdust is one of the most difficult techniques due to its uniformed shape, by using this instrument, it gives the ability of measuring the thermal conductivity of the sawdust, without changing its physical properties, during the experiment, as well as, there are no necessity to use the additional materials in form of adhesive materials, that gives an identified shape of the specimen. In this study, wood sawdust is classified into three groups depending on the size of the wood pellets, namely; wo1=1.18mm, 1.18>wo2>0.6mm and wo3=0.6mm. To keep out the thermal properties of the sawdust as it is, no mechanical or chemical processes were carried out on sawdust specimens, such as compressing or bonding. The effect of moisture content on the thermal properties of sawdust is eliminated by drying the specimens, the procedure is carried out by heating it up to 100° for a 30 min. During this study, it can be seen that the thermal conductivity of all samples is inversely proportional to the working temperature. At a relatively low temperature less than 45°, it can be said that the first model (wo1) has the lowest thermal conductivity while the differences in the thermal conductivity of the samples are insignificant when the temperature exceed 50°, therefore; the first model (wo1) represents a good choice for flat plate solar collector insulation because it has the same activity as well as it is light and cheap. [ABSTRACT FROM AUTHOR]

The accuracy of insulators and their defect identification by UAVs (unmanned aerial vehicles) in transmission-line inspection needs to be further improved, and the model size of the detection algorithm is significantly reduced to make it more suitable for edge-end deployment. In this paper, the algorithm uses a lightweight GhostNet module to reconstruct the backbone feature extraction network of the YOLOv4 model and employs depthwise separable convolution in the feature fusion layer. The model is lighter on the premise of ensuring the effect of image information extraction. Meanwhile, the ECA-Net channel attention mechanism is embedded into the feature extraction layer and PANet (Path Aggregation Network) to improve the recognition accuracy of the model for small targets. The experimental results show that the size of the improved model is reduced from 244 MB to 42 MB, which is only 17.3% of the original model. At the same time, the mAp of the improved model is 0.77% higher than that of the original model, reaching 95.4%. Moreover, the mAP compared with YOLOv5-s and YOLOX-s, respectively, is improved by 1.98% and 1.29%. Finally, the improved model is deployed into Jetson Xavier NX and run at a speed of 8.8 FPS, which is 4.3 FPS faster than the original model. [ABSTRACT FROM AUTHOR]

In higher eukaryotes, the regulation of developmental gene expression is determined by enhancers, which are often located at a large distance from the promoters they regulate. Therefore, the architecture of chromosomes and the mechanisms that determine the functional interaction between enhancers and promoters are of decisive importance in the development of organisms. Mammals and the model animal Drosophila have homologous key architectural proteins and similar mechanisms in the organization of chromosome architecture. This review describes the current progress in understanding the mechanisms of the formation and regulation of long-range interactions between enhancers and promoters at three well-studied key regulatory loci in Drosophila. [ABSTRACT FROM AUTHOR]

Uncovering the cis -regulatory code that governs when and how much each gene is transcribed in a given genome and cellular state remains a central goal of biology. Here, we discuss major layers of regulation that influence how transcriptional outputs are encoded by DNA sequence and cellular context. We first discuss how transcription factors bind specific DNA sequences in a dosage-dependent and cooperative manner and then proceed to the cofactors that facilitate transcription factor function and mediate the activity of modular cis -regulatory elements such as enhancers, silencers, and promoters. We then consider the complex and poorly understood interplay of these diverse elements within regulatory landscapes and its relationships with chromatin states and nuclear organization. We propose that a mechanistically informed, quantitative model of transcriptional regulation that integrates these multiple regulatory layers will be the key to ultimately cracking the cis -regulatory code. The cis -regulatory code dictates how DNA sequence controls quantitative transcription levels of each gene depending on cellular context. Kim and Wysocka review progress and challenges in understanding the layers of this code, from transcription factor binding to cofactor recruitment and ultimately cis -regulatory element specificity and function within complex regulatory landscapes. [ABSTRACT FROM AUTHOR]

The failure of insulators may seriously threaten the safe operation of the power system, where the state detection of high-voltage insulators is a must for the normal and safe operation of the power system. Based on the data of insulators in aerial images, this work explored an enhanced particle swarm algorithm to optimize the parameters of the support vector machine. A support vector machine model was therefore established for the identification of the normal and defective states of the insulators. This methodology works with the structure minimization principle of SVM and the characteristics of particle swarm fast optimization. First, the aerial insulator image was segmented as a target by way of the seed region growth based on double-layer cascade morphological improvements, and then, HOG features plus GLCM features were extracted as sample data. Finally, an ameliorated PSO-SVM classifier was designed to realize insulator state identification. Comparisons were made between PSO-SVM and conventional machine learning algorithms, SVM and Random Forest, and an optimization algorithm, Gray Wolf Optimization Support Vector Machine (GWO-SVM), and advanced neural network CNN. The experimental results showed that the performance of the algorithm proposed in this paper touched the top level, where the recognition accuracy rate was 92.11%, the precision rate 90%, the recall rate 94.74%, and the F1-score 92.31%. [ABSTRACT FROM AUTHOR]

Insulator determines the insulation level and power supply reliability of transmission lines. The traditional operation and maintenance method of insulators has a large workload. This paper presents an insulator recognition and fault diagnosis system based on image recognition and machine learning. Firstly, the composite insulators in complex backgrounds have been identified by Faster RCNN algorithm, which helps to extract the image of insulators by drone shot. Then, the cracking of umbrella skirts has been carried out by means of image processing. Also, the contamination of composite insulator umbrella skirts is also identified. The appropriate feature quantity by Fisher's discrimination is recommended, and the insulator contamination level has been identified by S component. Lastly, analyzing the infrared image of the insulator provides the basis for the normalization of insulator temperature rise detection results in different environments. Insulator image autonomous recognition and defect intelligent detection, which is based on deep reinforcement learning, is helpful for the operation, maintenance and repair of line insulators. [ABSTRACT FROM AUTHOR]

Performing ultrasonic nondestructive testing experiments on insulators and then using machine learning algorithms to classify and identify the signals is an important way to achieve an intelligent diagnosis of insulators. However, in most cases, we can obtain only a limited number of data from the experiments, which is insufficient to meet the requirements for training an effective classification and recognition model. In this paper, we start with an existing data augmentation method called DBA (for dynamic time warping barycenter averaging) and propose a new data enhancement method called AWDBA (adaptive weighting DBA). We first validated the proposed method by synthesizing new data from insulator sample datasets. The results show that the AWDBA proposed in this study has significant advantages relative to DBA in terms of data enhancement. Then, we used AWDBA and two other data augmentation methods to synthetically generate new data on the original dataset of insulators. Moreover, we compared the performance of different machine learning algorithms for insulator health diagnosis on the dataset with and without data augmentation. In the SVM algorithm especially, we propose a new parameter optimization method based on GA (genetic algorithm). The final results show that the use of the data augmentation method can significantly improve the accuracy of insulator defect identification. [ABSTRACT FROM AUTHOR]

In present decade, amidst all the remarkable equipment belonging to the power systems—the insulator stands out to be all-important because of their crucial role in power generation and transmission networks. Despite the above fact, they also transpire to have many constraints with respect to their normal function and longevity. Reports states that insulators are the weakest link due to their instant breakdown nature and other facts. Among all those notable facts, breakdown due to surface contamination of the insulators emerges to be intriguing for the present research world. Researchers present countless techniques to eliminate the same. Out of all the techniques, superhydrophobic coating stands out to be noteworthy for their resistance against moisture, wetting, ice and dust. Also, this coating outperforms the conventional RTV (Room Temperature Vulcanizing) silicone rubber coating with respect to delayed flashover occurrence. That is the time required for flashover occurrence is delayed in superhydrophobic coating. This novel attribute of superhydrophobic coating requires an experimental analysis. Hence, the proposed work serves this objective by preparing a superhydrophobic solution with PDMS (Polydimethylsiloxane) chemical. Results show that the contact angle and sliding angle of the water droplet dropped on this coating are above 170° and 5°, respectively. Simulation model for studying flashover occurrence, adhesion property of water was built using COMSOL Multiphysics Software. [ABSTRACT FROM AUTHOR]

Transformers play an essential role in power networks, ensuring that generated power gets to consumers at the safest voltage level. However, they are prone to insulation failure from ageing, which has fatal and economic consequences if left undetected or unattended. Traditional detection methods are based on scheduled maintenance practices that often involve taking samples from in situ transformers and analysing them in laboratories using several techniques. This conventional method exposes the engineer performing the test to hazards, requires specialised training, and does not guarantee reliable results because samples can be contaminated during collection and transportation. This paper reviews the transformer oil types and some traditional ageing detection methods, including breakdown voltage (BDV), spectroscopy, dissolved gas analysis, total acid number, interfacial tension, and corresponding regulating standards. In addition, a review of sensors, technologies to improve the reliability of online ageing detection, and related online transformer ageing systems is covered in this work. A non-destructive online ageing detection method for in situ transformer oil is a better alternative to the traditional offline detection method. Moreover, when combined with the Internet of Things (IoT) and artificial intelligence, a prescriptive maintenance solution emerges, offering more advantages and robustness than offline preventive maintenance approaches. [ABSTRACT FROM AUTHOR]

This article describes the improvement of volt standards based on the Josephson effect as a development stage of VNIIM quantum volt standards. The equipment was created and improved based on the "superconductor– insulator–superconductor"-type Josephson array for reproducing direct current voltages up to 10 V. This work presents the development results of transportable quantum standards based on the "superconductor– normal metal–superconductor" and "superconductor–insulator–normal metal–insulator–superconductor" Josephson anhysteretic arrays. The findings reveal that anhysteretic arrays can be used to reproduce constant voltages and voltages of the arbitrary form by approximating signals with Josephson taps and pulsed sigma-delta modulation, which reproduces voltages with a given harmonics level. The results of the study on the transfer of a unit of volt to the measuring channels of alternating voltages with high-precision analog-to-digital converters from the state primary standard of electric power units in the frequency range from 1 to 2500 Hz GET 153-2019 are presented. [ABSTRACT FROM AUTHOR]

The large band gap insulator LiCaAlF6 (LiCAF) has been proposed as a possible host crystal for future realizations of a solid‐state based thorium‐229 nuclear clock, due to its excellent optical transmission in the vacuum ultraviolet range. To enable direct optical manipulation of the thorium isomeric state, the band gap has to remain larger than the nuclear excitation energy upon crystal doping. Here, a systematic search for possible charge compensation mechanisms, defect locations, and the emergence of other compounds, using density functional theory, is presented. Out of 535 optimized structures, the energetically most favorable arrangement is ThAl•+VLi′${\mathrm{Th}}_{\mathrm{Al}}^{\bullet}+{\mathrm{V}}_{\mathrm{Li}}^{\prime}$ with an estimated band gap of 11.4 eV. Evaluating relevant uncertainties of the used methods suggests that the doped material remains transparent at the 229Th isomer energy for all investigated configurations. [ABSTRACT FROM AUTHOR]

Insulator pollution flashover has a high probability in the faults of transmission and distribution system. Due to its complex formation process and various influencing factors, the relevant studies are mostly based on experimental tests and empirical formulas, which do not fully consider the impact of random factors on the flashover process. The quantifiable algorithms are lacking, and it is difficult to effectively predict pollution flashover. In this article, the quantum transition theory is introduced in the streamer theory to calculate the energy-level transition probability of the particle on the surface of polluted insulator. The randomness of particle collision cross section is considered, and the initial discharge voltage is calculated by probability theory. The effects of active particle content, ambient temperature, and relative humidity on the initial charge number of insulator pollution flashover are analyzed. On this basis, the initial discharge process of insulator pollution flashover is studied. The experimental results show that the calculated results of insulator pollution flashover initial discharge voltage based on quantum energy-level transition probability are consistent with the experimental values, which has engineering application value for insulator pollution flashover prediction. [ABSTRACT FROM AUTHOR]

[Display omitted] Hierarchically porous ceramics possess tailored porosity across multiple length scales, giving rise to materials with low density, high specific properties, and multifunctionality. Here, we report a method that combines self-assembly and 3D printing to create ceramic architectures with hierarchical porosity spanning from the nano- to microscale. To programmably define their microscale porosity, an additive manufacturing method, known as direct ink writing, is used to create 3D lattices composed of cylindrical struts. Nanoscale porosity is generated within each strut by block copolymer templating followed by photopolymerization and pyrolysis in a non-oxidative environment, which transforms the preceramic polymer, polycarbosilane, into silicon oxycarbide with a "nanocoral" morphology. The resulting hierarchically porous ceramic lattices exhibit excellent mechanical energy absorption (0.31 MJ/m3), comparable to metal alloy foams. They also possess an order of magnitude lower thermal conductivity (0.087–0.16 W/m⋅K) compared to bulk preceramic polymer-derived ceramics. Prior to pyrolysis, the printed architectures can be manipulated to produce more complex shapes, including lattices with twisted, helical, and overhang features as well as repeated folding to create an origami airplane. By combining self- and directed assembly, our approach opens new avenues for creating hierarchically porous ceramics. [ABSTRACT FROM AUTHOR]

Chromatin insulators are DNA–protein complexes localized throughout the genome capable of establishing independent transcriptional domains. It was previously reported that the Drosophila su(Hw) mRNA physically associates with the gypsy chromatin insulator protein complex within the nucleus and may serve a noncoding function to affect insulator activity. However, how this mRNA is recruited to the gypsy complex is not known. Here, we utilized RNA-affinity pulldown coupled with mass spectrometry to identify a novel RNA-binding protein, Isha (CG4266), that associates with su(Hw) mRNA in vitro and in vivo. Isha harbors a conserved RNA recognition motif and RNA Polymerase II C-terminal domain-interacting domain (CID). We found that Isha physically interacts with total and elongating Polymerase II and associates with chromatin at the 50 end of genes in an RNA-dependent manner. Furthermore, ChIPseq analysis reveals Isha overlaps particularly with the core gypsy insulator component CP190 on chromatin. Depletion of Isha reduces enhancer-blocking and barrier activities of the gypsy insulator and disrupts the nuclear localization of insulator bodies. Our results reveal a novel factor Isha that promotes gypsy insulator activity that may act as a nuclear RNA-binding protein adapter for su(Hw) noncoding mRNA. [ABSTRACT FROM AUTHOR]

Polymers are widely used as insulation materials in the electrical industry because their existing electrical and mechanical properties can be altered by adding different types of additives. Successful prediction of the service life of the insulators used in the electrical industry is important for the reliability of the system. For this purpose, insulating materials are subjected to tests according to various standards. In this study, unlike the literature, a polymeric insulator was produced by adding 3 wt.% zinc oxide (ZnO), magnetite (Fe3O4), and nickel (Ni) into the polyester. The produced samples were subjected to the inclined plane test in accordance with ASTM (American Society for Testing and Materials) D-2303 standards. In order to analyze the electric and magnetic field distributions formed on the samples during the inclined plane test, first, the current flowing on the samples during the test was measured. Following this, analyses were carried out by creating a simulation model of the samples. Studies found in the literature mainly focus on two-dimensional investigation of the electrical field distribution. This study concentrates on the three-dimensional examination of the electrical field also considering the magnetic field distribution. Results of this study showed that prior numerical analysis gives insight into information about the real-life behavior of the samples. [ABSTRACT FROM AUTHOR]

In this article, the surface charge characteristics of the direct current gas-insulated transmission lines (DC-GIL) insulator under thermal–electric coupled fields are investigated. A horizontally installed GIL with a basin-type insulator is employed. The 3-D charge distribution under different ambient temperatures, load currents, and gas pressures is obtained based on the finite-element method. It is found that the charge density increases with increasing ambient temperature since the bulk conduction is promoted due to the increasing insulator temperature. At lower ambient temperature, the surface charge distribution shows a more obvious difference in different radial directions along the insulator due to the increasing difference in electric conductivity in different directions. With increasing load current, the charge density increases, and the difference in charge density in different radial directions becomes more obvious. The charge density increases with increasing gas pressure although the temperature decreases, which is attributed to the domination of decreasing ion mobility over decreasing bulk conduction. It can be concluded that attention should be paid to these conditions when dealing with the insulation property of DC-GIL considering the effect of thermal gradient on the charge accumulation. Besides, simulation based on a 3-D model is necessary, especially for horizontal GILs. [ABSTRACT FROM AUTHOR]

Surface charge accumulation on the insulator of direct current gas-insulated transmission lines (DC-GILs) under thermal-electric multiphysics fields is investigated using the finite element method (FEM). To obtain the accurate temperature and charge distributions in the horizontally installed gas-insulated transmission lines (GILs) with a basin-type insulator, a three-dimensional (3-D) geometric model is constructed. First, the equations and parameters are optimized to improve the computing efficiency. The thermal gradient (TG) negligibly affects the surface electrical conductivity. The recombination and diffusion terms in the ion transport equation can also be removed. After omitting these terms, the calculation efficiency is improved by approximately 70% without affecting the calculation accuracy. The surface charge density increases under TG but varies slightly in different radial directions along the insulator surface. In contrast, the electric field distribution obviously depends on the radial direction. The calculations confirm that the improved method properly analyzes the surface charge characteristics under thermal-electric fields and can thus evaluate the insulation performance of DC-GILs. [ABSTRACT FROM AUTHOR]

The organization of the genome into transcriptionally active and inactive chromatin domains requires well-delineated chromatin boundaries and insulator functions in order to maintain the identity of adjacent genomic loci with antagonistic chromatin marks and functionality. In plants that lack known chromatin insulators, the mechanisms that prevent heterochromatin spreading into euchromatin remain to be identified. Here, we show that DNA Topoisomerase VI participates in a chromatin boundary function that safeguards the expression of genes in euchromatin islands within silenced heterochromatin regions. While some transposable elements are reactivated in mutants of the Topoisomerase VI complex, genes insulated in euchromatin islands within heterochromatic regions of the Arabidopsis thaliana genome are specifically down-regulated. H3K9me2 levels consistently increase at euchromatin island loci and decrease at some transposable element loci. We further show that Topoisomerase VI physically interacts with S-adenosylmethionine synthase methionine adenosyl transferase 3 (MAT3), which is required for H3K9me2. A Topoisomerase VI defect affects MAT3 occupancy on heterochromatic elements and its exclusion from euchromatic islands, thereby providing a possible mechanistic explanation to the essential role of Topoisomerase VI in the delimitation of chromatin domains. [ABSTRACT FROM AUTHOR]

SF6/CF4 mixture is considered a potential substitution for SF6 in gas-insulated equipment owing to the considerable insulation and low temperature characteristics of CF4. This paper concerns the substitutability of the mixture on the surface flashover property. Epoxy resin composites for solid insulators are applied since flashover at the insulator interface often occurs and results in severe damage to the safe operation of the equipment. Two kinds of electrode systems are designed to study DC flashover properties with different electric field uniformities. The obtained result shows that the flashover voltage in the 20% SF6/80% CF4 mixture achieved more than 70% of the voltage in SF6 at the same pressure. The mixture shows considerable synergy in the surface flashover process and performed different tendencies with varying gas pressures and contents under different electrode systems due to the influence of surface accumulated charge. Moreover, it is considered that surface charge due to ionization may result in a reversal phenomenon for voltage polarity with increasing pressure. The results indicate the possibility of SF6/CF4 functioning as an efficient substitution of SF6 with a considerable insulation property and improved environmental protection characteristics. [ABSTRACT FROM AUTHOR]

This research aimed to find the process of value adding for glass wool waste from the glass wool composite board used in the vehicle industry. The waste was reprocessed to be an insulator and to determine the suitable conditions for hot-press forming to create new materials having high thermal resistant properties. Firstly, the properties of the original board; the thermal resistances (R) and the noise absorption coefficients (NRC), were measured and were found averages of 0.9055 m2K/W and 0.3955, respectively. The reprocessing conditions were varied by 2 levels; high and low, of 5 control factors; density, thickness, pressure, temperature, and surface roughness. Three repeating processes for each condition were performed. The Design of Experiment (DoE) was the full factorials; 25 experiments, by using the Analysis of Variance (ANOVA) to find main and interaction factors relating to the properties. From the ANOVA results with the α level of significance at 0.05, it was found that the main factors responding to the high values of the thermal resistance were the thickness and density. This resulted in the suitable conditions for the hot-press process of both the new smooth and rough pads with a density of 96 kg/m3 and a thickness of 25 mm. The R values of the new insulators were in between 0.88 - 0.98 m2K/W and, additionally, the high NRC values were also provided in between 0.46 - 0.49. These findings could be applied for wall designing, wall decorations and heat shields for indoor rooms and different types of buildings. [ABSTRACT FROM AUTHOR]

Herein, the deposition of homogeneous ZrxHf(1−x)O2 (x < 1) thin films for dynamic random‐access memory (DRAM) capacitor dielectric layers by atomic layer deposition (ALD) using a mixed precursor mixture of two precursors is investigated. ZrO2‐ and HfO2‐based thin films are widely used as capacitor dielectric layers because of their high dielectric constant (k) values and low leakage current properties. Herein, particularly, films with mixed structures of ZrO2/HfO2 are investigated because ZrO2 supports the growth of HfO2 in the tetragonal phase. However, the mixed structures deposited by ALD remain inhomogeneous even after the annealing process. The inhomogeneity results in part of the HfO2 remaining in the monoclinic phase, which reduces the k value. Herein, the formation of homogeneous tetragonal‐phase ZrxHf1−xO2 using a mixed precursor consisting of CpZr and CpHf precursors is investigated. The formation of the tetragonal phase in the ZrxHf(1−x)O2 thin films is determined through chemical and structural analysis. The variation of the electrical properties with the Zr/Hf concentration ratio is investigated. The electrical properties are enhanced compared to laminated ZrO2/HfO2 and single thin films. [ABSTRACT FROM AUTHOR]