scholarly journals Use of Grafted Voltage Stabilizer to Enhance Dielectric Strength of Cross-Linked Polyethylene

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Wei Dong ◽  
Xuan Wang ◽  
Bo Tian ◽  
Yuguang Liu ◽  
Zaixing Jiang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Breakdown Strength ◽  
Dielectric Strength ◽  
Voltage Stabilizer ◽  
Cross Linking ◽  
Practical Application ◽  
Electrical Tree ◽  
Research Goal ◽  
The Stability ◽  
New Research

Aromatic voltage stabilizers can improve the dielectric properties of cross-linked polyethylene (XLPE); however, their poor compatibility with XLPE hinders their practical application. Improving the compatibility of aromatic voltage stabilizers with XLPE has, therefore, become a new research goal. Herein 1-(4-vinyloxy)phenylethenone (VPE) was prepared and characterized. It can be grafted onto polyethylene molecules during the cross-linking processes to promote stability of the aromatic voltage stabilizers in XLPE. Fourier transform infrared spectroscopy confirmed that VPE was successfully grafted onto XLPE, and effectively inhibited thermal migration. Thermogravimetric analysis showed that the grafted VPE/XLPE composite exhibits a better thermal stability than a VPE/PE blend composite. Evaluation of the electrical properties showed that the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 15.5% and 39.6%, respectively, when compared to those of bare XLPE. After thermal aging, the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 9.4% and 25.8%, respectively, in comparison to those of bare XLPE, which indicates that the grafted voltage stabilizer can effectively inhibit its migration and enhance the stability of the composite material.

Theoretical study on the radical reaction mechanism in the cross-linking process of polyethylene

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90343-90353 ◽  
Author(s):  
Hui Zhang ◽  
Yan Shang ◽  
Mingxia Li ◽  
Hong Zhao ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
High Voltage ◽  
Theoretical Study ◽  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Radical Reaction ◽  
Voltage Stabilizer ◽  
Cross Linking ◽  
Insulation Material ◽  
Electrical Breakdown Strength

The mechanism of the valerophenone voltage stabilizer for increasing the electrical breakdown strength of cross-linked polyethylene is expected to provide reliable information to prepare insulation material for high voltage cables up to 500 kV.

scholarly journals Стабильность функциональных характеристик прозрачных электродов на основе трехслойной структуры ZnO : Ga/Ag/ZnO : Ga

2022 ◽  
Vol 48 (2) ◽  
pp. 51
Author(s):  
А.Ш. Асваров ◽  
А.К. Ахмедов ◽  
А.Э. Муслимов ◽  
В.М. Каневский
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Room Temperature ◽  
Layer Structure ◽  
Visible Range ◽  
Practical Application ◽  
Transparent Conducting ◽  
Average Transmittance ◽  
The Stability

Since to the stability of the functional properties of a transparent conducting three-layer structure ZnO:Ga/Ag/ZnO:Ga is important for practical application, we studied its long-term durability and thermal stability in air environment. It has been demonstrated that after prolonged interaction with the air environment at room temperature (~ 1000 h) and further heat treatment in air at temperatures up to 450 ° C (up to 10 h), the three-layer structure retains its integrity and is characterized by a low sheet resistance Rs = 2.8 Ω/sq at average transmittance in the visible range Tav of 82.1%.

Formation and Characterization of Shellac Phthalate Succinate through Organic Solvent-Free Reaction

2012 ◽  
Vol 506 ◽  
pp. 186-189
Author(s):  
T. Sangnim ◽  
J. Nunthanid ◽  
M. Luangtana-Anan ◽  
C. Limmatvapirat ◽  
Sontaya Limmatvapirat
Keyword(s):  
Thermal Stability ◽  
Organic Solvent ◽  
Succinic Anhydride ◽  
Acid Value ◽  
Solvent Free ◽  
Cross Linking ◽  
Ester Linkage ◽  
The Stability ◽  
Solvent Free Reaction

The objective of this study was to synthesize shellac phthalate succinate (SHL-PHT-SUC) through organic solvent-free reaction. Firstly, shellac phthalate (SHL-PHT) was prepared by co-grinding and annealing shellac (SHL) with phthalic anhydride (PHTA). The SHL-PHT was subsequently ground with succinic anhydride (SUCA) and activated by the same process to obtain SHL-PHT-SUC. The formation of all SHL derivatives was investigated by the monitoring acid value, insoluble solid and later confirmed by FTIR spectroscopy. The result indicated that the acid value was increased after annealing SHL-PHT with SUCA, suggesting the addition of succinate moiety at SHL-PHT molecule. The presence of C-O stretching of ester linkage was also observed in the FTIR spectrum. The results suggested the formation of SHL-PHT-SUC by esterification. In addition, the thermal stability was assessed by ageing the SHL derivatives at 100°C for 24 h. The SHL-PHT-SUC demonstrated lower stability as compared to SHL-PHT. The stability of SHL derivatives appeared to be related with the cross-linking of the polymer chain. In the case of SHL-PHT-SUC, succinate group, having more molecular mobility, this might encourage fast and extensive cross-linking as compared to the phthalate group and thus promoted the ageing process.

scholarly journals Effect of Acetylated SEBS/PP for Potential HVAC Cable Insulation

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1811
Author(s):  
Peng Zhang ◽  
Xuan Wang ◽  
Jiaming Yang ◽  
Yongqi Zhang
Keyword(s):  
Breakdown Strength ◽  
Thermoplastic Elastomer ◽  
Alternating Current ◽  
High Energy ◽  
Voltage Stabilizer ◽  
Breakdown Field ◽  
Isomerization Reaction ◽  
Insulation Material ◽  
Tree Resistance ◽  
Electrical Tree

Blending polypropylene (PP) with thermoplastic elastomer SEBS can effectively improve the mechanical toughness of PP, thus leading to the promise of SEBS/PP as the primary insulation material for high voltage alternating current (HVAC) cables. However, the growth of electrical trees during cable operation limits the application of SEBS/PP. In this paper, acetylation reaction is used to construct acetophenone group at the end of the benzene ring on SEBS so that it has the effect of both a toughening agent and a voltage stabilizer. Then PP was melt blended with acetylated SEBS (Ac-SEBS), and the effects of Ac-SEBS on the mechanical properties, electrical tree resistance, alternating current (AC) breakdown strength, and dielectric spectrum of PP were mainly investigated with reference to PP and SEBS/PP. The results showed that Ac-SEBS with 30% content could enhance the mechanical toughness of PP and improve the electrical tree resistance and AC breakdown strength of SEBS/PP. The AC breakdown field strength of Ac-SEBS/PP reached the highest when the acetylation level was 4.6%, which was 9.2% higher than that of SEBS/PP. At this time, Ac-SEBS was also able to absorb high-energy electrons through the keto-enol interchange isomerization reaction, which inhibited the initiation and growth of electric trees and caused the development of electric dendrites in a jungle-like manner. Moreover, the dielectric loss factor of AC-SEBS/PP in power frequency is within the allowable range of industry. Therefore, Ac-SEBS/PP is expected to be applied to HVAC cables, thus further improving the efficiency of HVAC power transmission.

Electrical Treeing Breakdown Properties for Polyimide Nanocomposite Film in Inverter-Fed Motors

2012 ◽  
Vol 455-456 ◽  
pp. 553-558
Author(s):  
Yi Cui ◽  
Guang Ning Wu ◽  
Yi Qiang Zhang ◽  
Zheng Liang Xin ◽  
Yang Luo
Keyword(s):  
Energy Spectrum ◽  
Spectrum Analysis ◽  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Dielectric Strength ◽  
Main Body ◽  
Energy Spectrum Analysis ◽  
Electrical Tree ◽  
Magnet Wire ◽  
Turn Insulation

The failure of magnet wires used in inter-turn insulation of inverter-fed motor winding is the main cause which leads to the motor insulation breakdown. This paper conducted electrical tree breakdown experiments on magnet wire insulating film (FCR 100) used in the inter-turn insulation of JD117 inverter-fed motor and meanwhile combining with energy spectrum analysis and scanning electrical microscope (SEM), by which type and content of elements, breakdown main body and electrical tree channel could be clearly observed, the corresponding failure mechanisms were analyzed. The experiment results reveal that all the breakdown main bodies are located at the pointedness and insulation joint of magnet wires, of which dielectric strength is relatively lower; they are the insulation “weak point”, which should be paid enough attention and strengthened at the manufacturing period. The electrical tree breakdown time is quite long and the life span of magnet wire is 11 hours. The electrical breakdown strength of envelope is very low when containing metal impurity. It is also found that the aluminum occupies the highest content tested by energy spectrum analysis.

scholarly journals The Real-Time Depth Estimation for an Occluded Person Based on a Single Image and OpenPose Method

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1333 ◽  
Author(s):  
Yu-Shiuan Tsai ◽  
Li-Heng Hsu ◽  
Yi-Zeng Hsieh ◽  
Shih-Syun Lin
Keyword(s):  
Deep Learning ◽  
Machine Vision ◽  
Three Dimensional ◽  
Depth Estimation ◽  
Distance Measurement ◽  
Portable Devices ◽  
Practical Application ◽  
Single Lens ◽  
Research Goal ◽  
New Research

In recent years, the breakthrough of neural networks and the rise of deep learning have led to the advancement of machine vision, which has been commonly used in the practical application of image recognition. Automobiles, drones, portable devices, behavior recognition, indoor positioning and many other industries also rely on the integrated application, and require the support of deep learning and machine vision. As for these technologies, there is a high demand for the accuracy related to the recognition of portraits or objects. The recognition of human figures is also a research goal that has drawn great attention in various fields. However, the portrait will be affected by various factors such as height, weight, posture, angle and whether it is covered or not, which affects the accuracy of recognition. This paper applies the application of deep learning to portraits with different poses and angles, especially the actual distance of a single lens for the shadowed portrait (depth estimation), so that it can be used for automatic control of drones in the future. Traditional methods for calculating depth using images are mainly divided into three types: one—single-lens estimation, two—lens estimation, and three—optical band estimation. In view of the fact that both the second and third categories require relatively large and expensive equipment to effectively perform distance calculations, numerous methods for calculating distance using a single lens have recently been produced. However, whether it is the use of traditional “units of distance measurement calibration”, “defocus distance measurement”, or the “three-dimensional grid space messages distance measurement method”, all of these face corresponding difficulties and problems. Additionally, they have to deal with outside disturbances and process the shadowed image. Therefore, under the new research method, OpenPose, which is proposed by Carnegie Mellon University, this paper intends to propose a depth algorithm for a single-lens occluded portrait to estimate the actual portrait distance for different poses, angles of view and obscuration.

scholarly journals Mechanical and Dielectric Strength of Laminated Epoxy Dielectric Graded Materials

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 622
Author(s):  
Chuang Wang ◽  
Qing Sun ◽  
Lang Zhao ◽  
Jing Jia ◽  
Lixiao Yao ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Breakdown Strength ◽  
Dielectric Material ◽  
Dielectric Strength ◽  
Structural Motif ◽  
Cross Linking ◽  
Graded Materials ◽  
Interfacial Structures ◽  
Graded Material ◽  
Laminated Material

Laminated epoxy dielectric graded material is a commonly used insulating material with broad application prospects in power equipment. The interlaminar interfaces of laminated epoxy dielectric material between different layers form during its lamination process, and these interfaces are the crucial characteristic structures determining the mechanical and dielectric properties of laminated materials. Therefore, in order to gain a thorough understanding of physic properties behind a certain structural motif, it is necessary to study how these interfacial structures influence the mechanical and dielectric performances of graded materials. In this study, double-layered epoxy resin samples with an interlaminar interface are prepared to study their mechanical and dielectric strength. More importantly, the formation mechanism of the interface, as well as its influence on the mechanical and dielectric strength of this laminated material, is discussed. We found that a cross-linking reaction may take place between epoxy resins at the interlaminar interface, and the degree of cross-linking at the interface should be less than that in the bulk. The mechanical strength of the interlaminar interface is weaker than that of the bulk, and it is reduced by less than 40%. Moreover, the interlaminar interface is inclined to trap carriers, which improves the breakdown strength and arc ablation resistance of the laminated material. Our study of interlaminar interface properties could help in designing epoxy dielectric graded materials with better mechanical and dielectric properties.

scholarly journals Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study

2021 ◽  
Vol 22 (7) ◽  
pp. 3346
Author(s):  
Agata Sommer ◽  
Paulina Dederko-Kantowicz ◽  
Hanna Staroszczyk ◽  
Sławomir Sommer ◽  
Marek Michalec
Keyword(s):  
Thermal Stability ◽  
Bacterial Cellulose ◽  
Secondary Alcohol ◽  
Water Vapor Permeability ◽  
Polymer Chains ◽  
Cross Linking ◽  
Vapor Permeability ◽  
Covalent Bonds ◽  
Fish Collagen ◽  
Chemical Cross Linking

This article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, and their functional properties by mechanical and water barrier tests. While polymer chains in uncross-linked BC/Col are intertwined by H-bonds, new covalent bonds in enzymatically cross-linked ones are formed—resulting in increased thermal stability and crystallinity of the material. The C2–C3 bonds cleavage in D-glucose units, due to BC oxidation, cause secondary alcohol groups to vanish in favor of the carbonyl groups’ formation, thus reducing the number of H-bonded OHs. Thermal stability and crystallinity of oxBC/Col remain lower than those of BC/Col. The BC/Col formation did not affect tensile strength and water vapor permeability of BC, but enzymatic cross-linking with TGGS improved them significantly.

Optimization of Organic Fibres%[Kevlar/Arobocel/Acrylic] in NAO Brake Pad Application and its Effect on Thermal Stability & Friction Characteristics

2012 ◽  
Vol 531-532 ◽  
pp. 8-12
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Minimum Weight ◽  
Friction Material ◽  
Brake Pad ◽  
Temperature Zone ◽  
Good Thermal Stability ◽  
Friction Testing ◽  
Brake Application ◽  
The Stability

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.

The Application of Bayesian Statistics in Calculating Project Buffer

2011 ◽  
Vol 58-60 ◽  
pp. 1018-1024
Author(s):  
Feng Ye ◽  
Gui Chen Xu ◽  
Di Kang Zhu
Keyword(s):  
Bayesian Statistics ◽  
Statistical Approach ◽  
Implementation Process ◽  
Current Method ◽  
Practical Application ◽  
Great Flexibility ◽  
Crystal Ball ◽  
Simulation Results ◽  
The Stability

This paper reviews several current methods of calculating buffer on the basis of pointing out each merits and pitfalls and then introduces Bayesian statistical approach to CCS / BM domain to calculate the size of the project buffer, to overcome that the current method of the buffer calculation is too subjective and the defect on lacking of practical application. In Crystal Ball, we compare the simulation results of implementation process on the benchmark of C&PM, RESM and SM. The results show that the buffer using this method can ensure the stability of the project’s completion probability, and this method has great flexibility.

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