scholarly journals Research on Lifespan Prediction of Cross-Linked Polyethylene Material for XLPE Cables

2020 ◽  
Vol 10 (15) ◽  
pp. 5381
Author(s):  
Yi Zhang ◽  
Zaijun Wu ◽  
Cheng Qian ◽  
Xiao Tan ◽  
Jinggang Yang ◽  
...  
Keyword(s):  
Operating Time ◽  
Prediction Method ◽  
Hardness Test ◽  
High Accuracy ◽  
Future Research ◽  
Test Results ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
Gel Content ◽  
Mechanical And Electrical Properties

In this paper, cross-linked polyethylene (XLPE) cables of the same batch from Factory A, which ran from 1 to 8 years in Jiangsu Province, are sampled. Some widely accepted aging characterization methods of XLPE cables such as the gel content test, differential scanning calorimetry (DSC) test, tensile test and hardness test are employed to obtain the physicochemical, mechanical and electrical properties of the samples. Then, some lifespan prediction parameters significantly correlated with operating time are obtained through correlation calculations. Finally, a prediction method is proposed to predict the operating time of XLPE cables from Factory A. The test results indicate that parameters including the gel content Cge, the crystallinity XC, tensile strength σ, ultimate elongation δ, the dielectric permittivity ε, and the dielectric loss Jtan are significantly correlated with operating time, which can be used in evaluating the aging degree of XLPE cables. Moreover, due to the high accuracy of the experimental verification, it turns out that the lifespan prediction method proposed in this paper can be used to determine the operating time of XLPE cables from Factory A in future research.

Study on the Lifespan Prediction of Silicon Rubber Nanocomposites Under High Humidity and High Temperature Environment

2020 ◽  
Vol 12 (10) ◽  
pp. 1469-1475
Author(s):  
Dongdong Zhang ◽  
Xin Liu ◽  
Chengshun Yang ◽  
Lianghua Ni ◽  
Xiaoning Huang ◽  
...  
Keyword(s):  
High Temperature ◽  
Operating Time ◽  
Prediction Method ◽  
Test Method ◽  
High Humidity ◽  
Insulation Material ◽  
Test Results ◽  
Silicon Rubber ◽  
Rubber Nanocomposites ◽  
Prediction Parameters

In this paper, the silicon rubber nanocomposites samples cut from the composite insulators operating in high humidity and high temperature areas for 0–13 years were taken as the research object. In accordance to previous research experiences, test methods such as static contact angle method, hardness test method were employed to investigate the changing law of lifespan prediction parameters with operating time. Based on test results, some lifespan prediction parameters significantly correlated with operating time were filtered by means of correlation calculation. On this basis, a prediction method which can be used to determine the operating time of the nanocomposites was proposed based on BP neural network. Test results indicate that lifespan prediction parameters including HC, θ, A, T, H, XO were significantly correlated with the operating time of the insulation material from composite insulator, and these parameters can be used to characterize the aging degree accurately. Besides, due to the high accuracy in experimental verification, the lifespan prediction method proposed in this paper can be used to determine the operating time of composite insulators from transmission lines in future research.

scholarly journals Laboratory Study of the Ultraviolet Radiation Effect on an HDPE Geomembrane

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Fernando Luiz Lavoie ◽  
Marcelo Kobelnik ◽  
Clever Aparecido Valentin ◽  
Érica Fernanda da Silva Tirelli ◽  
Maria de Lurdes Lopes ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Morphological Changes ◽  
Field Performance ◽  
Melt Flow Index ◽  
Flow Index ◽  
Test Results ◽  
Upward Trend ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Brittle Behavior

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radiation, thermal and oxidative exposure, and chemical contact. This article presents an experimental study with a 1.0 mm-thick HDPE virgin geomembrane exposed by the Xenon arc weatherometer for 2160 h and the ultraviolet fluorescent weatherometer for 8760 h to understand the geomembrane’s behavior under ultraviolet exposure. The evaluation was performed using the melt flow index (MFI) test, oxidative-induction time (OIT) tests, tensile test, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. The sample exposed in the Xenon arc equipment showed a tendency to increase the MFI values during the exposure time. This upward trend may indicate morphological changes in the polymer. The tensile behavior analysis showed a tendency of the sample to lose ductility, without showing brittle behavior. The samples’ OIT test results under both device exposures showed faster antioxidant depletion for the standard OIT test than the high-pressure OIT test. The DSC and FTIR analyses did not demonstrate the polymer’s changes.

scholarly journals PENINGKATAN SIFAT MEKANIS BESI COR KELABU MELALUI PROSES TEMPERING

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
A. Noor Setyo HD ◽  
Sri Widodo
Keyword(s):  
Cold Water ◽  
Hardness Test ◽  
Heating Time ◽  
Initial Energy ◽  
Test Results ◽  
Maximum Hardness ◽  
Quenching Temperature ◽  
Independent Variables ◽  
Hardness Tester ◽  
Water Media

This study aims to determine the Hardness and Toughness of cast iron after undergoing a Tempering process with independent variables heating time and dependent Hardness, microstructure and toughness Impack. Quenching was carried out at temperatures of 7750C, 8000C and 8250C in cold water media, while Tempering was carried out at temperatures of 2000C, 3000C and 4000C with a holding time of 15 minutes. Vickers Hardness test results using "Micro Hardness Tester" after Quenching have increased by an average of 95.6% at Quenching 7750C, 99.8% at Quenching 8000C and 107.1% at Quenching temperature 8250C from Hardness value of row material of 256.6 BHN or 260.8 VHN0,040. The maximum hardness value is obtained 531.4 BHN or 553.6 VHN 0,040 at Quenching temperature 8250C and the lowest Hardness of 501.8 BHN or 541,8 VHN0,040 at Quenching 7750C temperature, has Cementite phase as a matrix with little Martensite, is due to treatment The partial tempering of Martensite is replaced by the ferrite phase between Cementites. The results of the study concluded that at Tempering temperatures of 2000C, 3000C and 4000C, the toughness of FC 30 experienced an increase of 106.5%, 121.9% and 130.5% from the initial energy of 5.21 Joule / mm2, whereas violence decreased by 88, 6%, 80.8% and 40.4% of the original Hardness of 260.8 VHN 0,040

scholarly journals Methodology for Assessing the Transport Accessibility of Capital Objects in a Megacity Based on Geoinformation Data

2022 ◽  
Vol 12 (4) ◽  
pp. 400-415
Author(s):  
S. V. Mkhitaryan ◽  
Zh. B. Musatova ◽  
T. V. Murtuzalieva ◽  
G. S. Timokhina ◽  
I. P. Shirochenskaya
Keyword(s):  
Transport Infrastructure ◽  
Future Research ◽  
Infrastructure Development ◽  
Test Results ◽  
Transport Accessibility ◽  
Methodological Approaches ◽  
Secondary Information ◽  
Quantitative Indicators ◽  
The City ◽  
Housing Estates

Purpose: to present the author's methodology and the test results for calculating integral indicators of transport accessibility on the basis of weighted normalized private indicators for three housing estates in Moscow.Methods: the study is based on the application of methods for collecting factual material, its processing, systematic, comparative historical and structural-functional analysis, which were supplemented by multivariate analysis of secondary information using content analysis of existing methods for calculating indicators of transport accessibility of capital objects. The results and conclusions of the research are based on the use of the author's methodology for calculating integral indicators of transport accessibility based on weighted normalized private indicators for three housing estates in Moscow. The analysis of a possible set of criteria for assessing transport accessibility of housing estates in Moscow metropolis was carried out on the basis of the use of a geographic information system database GIS NextGIS QGIS.Results: a review of methodological approaches to the calculation of objective quantitative indicators characterizing the transport accessibility of capital objects is carried out; the author's methodology for calculating the integral indicators of the transport accessibility of residential complexes in Moscow is presented and tested on the basis of weighted normalized private criteria / indicators. The use of the authors’ methodology for calculating integral indicators of transport accessibility based on weighted normalized private criteria / indicators made it possible to calculate the values of indicators of transport accessibility for three housing estates in Moscow, calculate an integrated score for a set of transport accessibility criteria for each housing estate, to give a comparative quantitative assessment of their transport accessibility, to conduct a rating of housing estates in terms of their transport accessibility.Conclusions and Relevance: the presented results of approbation of the author's methodology for calculating the integral indicators of transport accessibility for housing estates in Moscow allow to conduct a comparative and dynamic analysis of housing estates (or larger units) transport accessibility. The results of such an analysis can be applied in order to develop programs for transport infrastructure development of the megacity as a whole, its certain districts and city parts, as well as to assess such programs efciency. The authors see the directions for future research in the defnition and calculation of indicators based on the city dwellers perception of the transport accessibility

scholarly journals Evaluation of graphene/crosslinked polyethylene for potential high voltage direct current cable insulation applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuan Li ◽  
Guangya Zhu ◽  
Kai Zhou ◽  
Pengfei Meng ◽  
Guodong Wang
Keyword(s):  
Space Charge ◽  
High Voltage ◽  
Direct Current ◽  
Tensile Yield Strength ◽  
Scanning Calorimetry ◽  
Crosslinking Degree ◽  
High Voltage Direct Current ◽  
Water Tree ◽  
Mechanical And Electrical Properties ◽  
Aging Test

AbstractThis paper evaluates the potential usage of graphene/crosslinked polyethylene (graphene/XLPE) as the insulating material for high voltage direct current (HVDC) cables. Thermal, mechanical and electrical properties of blends with/without graphene were evaluated by differential scanning calorimetry (DSC), tensile strength, DC conductivity, space charge measurements and water tree aging test. The results indicate that 0.007–0.008% weight amount of graphene can improve the mechanical and electrical insulation properties of XLPE blends, namely higher tensile/yield strength, improved space charge distribution, and shorter/fewer water tree branches. The improvements mainly attribute to the high stiffness of graphene, deep traps introduced by the interaction zones of graphene and XLPE, and the blockage effect of graphene within XLPE. For thermal performance of XLPE blends, graphene nano-fillers have but limited improvement. The crystallinity of the blends barely changes with the addition of graphene. However, the crosslinking degree increases as the additive-like amounts of graphene doped. The above findings provide a guide for tailoring lightweight XLPE materials with excellent mechanical and electrical performances by doping them with a small amount of graphene.

Mask Image Planning for Deformation Control in Projection-Based Stereolithography Process

2012 ◽  
Author(s):  
Kai Xu ◽  
Yong Chen
Keyword(s):  
Epoxy Resins ◽  
Lower Cost ◽  
Shape Deformation ◽  
Future Research ◽  
Test Results ◽  
Digital Micromirror Device ◽  
Research Directions ◽  
Deformation Control ◽  
Size Accuracy ◽  
Future Research Directions

In this research, we investigate the shrinkage related deformation control for a mask-image-projection-based Stereolithography process (MIP-SL). Based on a Digital Micromirror Device (DMD), MIP-SL uses an area-processing approach by dynamically projecting mask images onto a resin surface to selectively cure liquid resin into layers of an object. Consequently, the related additive manufacturing process can be much faster with a lower cost than the laser-based Stereolithography Apparatus (SLA) process. However, current commercially available MIP-SL systems are based on Acrylate resins, which have bigger shrinkages than epoxy resins that are widely used in the SLA process. Consequently controlling size accuracy and shape deformation in the MIP-SL process is challenging. To address the problem, we evaluate different image exposing strategies for projection mask images. A mask image planning method and related algorithms have been developed for the MIP-SL process. The planned mask images have been tested by using a commercial MIP-SL machine. The experimental results illustrate that our method can effectively reduce the deformation by as much as 32%. A discussion on the test results and future research directions are also presented.

Influence of Cadmium Oxide on Thermal Hazard of AP-CMDB Propellants

2015 ◽  
Vol 1095 ◽  
pp. 419-422 ◽  
Author(s):  
Hao Nan Jia ◽  
Gui E Lu ◽  
Zhen Tao An ◽  
Jin Yong Jiang ◽  
Qiang Ge ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Decomposition Rate ◽  
Initial Temperature ◽  
Cadmium Oxide ◽  
Thermal Hazard ◽  
Test Results ◽  
Thermal Safety ◽  
Scanning Calorimetry ◽  
Two Stages

The influence of cadmium oxide on the thermal decomposition behaviors of AP-CMDB propellants was studied by differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). The test results show that the decomposition process of AP-CMDB can be divided into two stages. Cadmium oxide can increase the initial temperature, slow down the decomposition rate and improve the thermal safety of AP-CMDB.

scholarly journals Effects of Biceramic AlN-SiC Microparticles on the Thermal Properties of Paraffin for Thermal Energy Storage

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Arash Badakhsh ◽  
Kay-Hyeok An ◽  
Chan Woo Park ◽  
Byung-Joo Kim
Keyword(s):  
High Frequency ◽  
Interfacial Adhesion ◽  
Ceramic Powder ◽  
Efficient Production ◽  
Ceramic Powders ◽  
Short Term ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
Thermal Features ◽  
Change Material

Herein, simplified time-efficient production of AlN-coated SiC (SiC@AlN) ceramic powder was practiced. Short-term vibratory ball milling with high frequency was employed to integrate the microsize particles. Also, paraffin as a significant phase change material (PCM) was reinforced using the manufactured SiC@AlN in order to enhance the thermal conductivity (TC) and stability of the final composite. Various characterization methods were used to clarify the changes in particle size of the biceramic powder as well as the thermal features of the paraffin-based composite. Manufactured SiC@AlN was found to be the most effective in the improvement of interfacial adhesion of composite components and the subsequent enhancement of TC, compared with singular ceramic powders as the reinforcing agents. Also, differential scanning calorimetry (DSC) indicated a very slight increase in latent heat of the fabricated composite PCM.

Conclusion, Limitations, and Future Research

2013 ◽  
pp. 234-241 ◽  
Keyword(s):  
Empirical Test ◽  
Future Research ◽  
Test Results ◽  
Major Research ◽  
Research Findings

This chapter summarizes the major research findings of this study based on the empirical test results throughout the previous chapters. The contributions and limitations of this research are also addressed. The study concludes by proposing several valuable directions for future research.

scholarly journals Measurement and Evaluation of Calorimetric Descriptors for the Suitability for Evolutionary High-Throughput Material Development

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 149 ◽  
Author(s):  
Anastasiya Toenjes ◽  
Heike Sonnenberg ◽  
Christina Plump ◽  
Rolf Drechsler ◽  
Axel von Hehl
Keyword(s):  
Heating Rate ◽  
High Throughput ◽  
Macro Level ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
Material Development ◽  
First Results ◽  
Novel Method ◽  
Measurement And Evaluation

A novel method for evolutionary material development by using high-throughput processing is established. For the purpose of this high-throughput approach, spherical micro samples are used, which have to be characterized, up-scaled to macro level and valued. For the evaluation of the microstructural state of the micro samples and the associated micro-properties, fast characterization methods based on physical testing methods such as calorimetry and universal microhardness measurements are developed. Those measurements result in so-called descriptors. The increase in throughput during calorimetric characterization using differential scanning calorimetry is achieved by accelerating the heating rate. Consequently, descriptors are basically measured in a non-equilibrium state. The maximum heating rate is limited by the possibility to infer the microstructural state from the calorimetric results. The substantial quality of the measured descriptors for micro samples has to be quantified and analyzed depending on the heating rate. In this work, the first results of the measurements of calorimetric descriptors with increased heating rates for 100Cr6 will be presented and discussed. The results of low and high heating rates will be compared and analyzed using additional microhardness measurements. Furthermore, the validation of the method regarding the suitability for the evolutionary material development includes up-scaling to macro level and therefore different sample masses will be investigated using micro and macro samples during calorimetry.

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