scholarly journals Analysis of the Influence of Silicone Rubber Aging on the Transmission Parameters of Terahertz Waves

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4238
Author(s):  
Haitao Yang ◽  
Zhensheng Wu ◽  
Weinan Dong ◽  
Junpeng Dang ◽  
Hao Ren

In this study, a method for testing the aging of silicone rubber insulators using terahertz waves in the 0.17–0.22 THz frequency band is proposed, aiming at the problem of online non-destructive testing of the aging degree of composite insulators. The relationship between the aging degree of silicone rubber composite insulators and the relative dielectric constant was studied through first-principles calculations and molecular chain scission models. In addition, the electromagnetic model of the terahertz signal incident on the silicon rubber sheet was simulated and the relationship between the aging degree of the silicon rubber and the terahertz input return loss was obtained. Eleven insulator samples with different degrees of aging were selected. In these samples, the degree of aging was calibrated according to the degree of surface deterioration and the average partial discharge voltage. The terahertz return loss measurement experiment was performed after that. Finally, the results of experiment and calculation simulation were compared and the reliability of the relationship between the aging degree of the silicone rubber insulator and the terahertz input return loss was verified.

2017 ◽  
Vol 50 (1) ◽  
pp. 36-57 ◽  
Author(s):  
Nurul Hidayah ◽  
Mariatti Mustapha ◽  
Hanafi Ismail ◽  
Mohamad Kamarol

This study determines the applicability of nanofillers (silica, boron nitride, and zinc oxide) in linear low-density polyethylene (LLDPE)/silicone rubber (SR) insulation compounds. Design of experiment is adopted to model the relationship between the properties (permittivity, loss tangent, dielectric strength, and volume resistivity) and factors (SR content, type of nanofiller, and nanofiller loading) for performance optimization. It is observed that SR content and type of nanofiller significantly influence the electrical properties of LLDPE/SR nanocomposites. Nanofiller loading, however, causes a small variation in the properties of the nanocomposites except for dielectric strength. From the optimization, it is found that the optimum formulation composition is 10 wt% of SR and 2 vol% of nanoboron nitride.


2020 ◽  
Vol 10 (7) ◽  
pp. 2297
Author(s):  
Yiqin Jiang ◽  
Zilong Liu ◽  
Yuxiao Li ◽  
Jin Li ◽  
Yusheng Lian ◽  
...  

The standardization of grayscale display is essentially significant for image signal communication, transmission, and terminal reading. The key step of this standardization is establishing a traceable equipment of grayscale. As a relative value, grayscale is transferred to two different absolute values to satisfy different traceability methods, including optical density for hardcopy image and luminance for softcopy. For luminance, a generation equipment is designed to build the relationship between luminance and grayscale. In this work, novel equipment is established using digital light processing (DLP) by time-frequency modulation, and the corresponding uncertainty is analyzed. The experiment result shows that this digital equipment builds the relationship between grayscale and luminance in the range of 0.16-4000 cd/m2. It enables traceable measurement of grayscale to luminance on this equipment with high accuracy and can provide a standardized reference for the display of grayscale images in the fields of medicine, remote sensing, non-destructive testing, etc.


Author(s):  
Г.Д. КОКОРЕВ ◽  
Е.А. ЖУРАВЛЕВА

В исследовании рассмотрены некоторые составляющие технической эксплуатации автомобильной техники (АТ), связанные с диагностированием топливной аппаратуры двигателей внутреннего сгорания (ДВС), причем с целью осуществления неразрушающего контроля предлагается применять ультразвуковую и акустико-эмиссионную системы технического диагностирования.Необходимо констатировать, что при рассмотрении соотношений, показывающих взаимосвязь акустических и физико-механических параметров материалов, в основном используется временной интервал, и при его некорректном измерении получаем низкую информативность и невысокую точность акустических методов определения механических характеристик. При разработке методики использованы принципы спектрального анализа импульсов, отраженных от исследуемых элементов АТ, на которых опирается также метод разработки как аппаратного так и программного обеспечения для обработки полученных сигналов. Результаты предыдущих исследований дают основание полагать, что применение преобразований Фурье обеспечивает получение достоверной информации, основанной на акустических сигналах, если последовательность измерений составляет около 10 секунд. Опыт разработчиков системы свидетельствует о высокой информативности параметров распространения рэлеевских волн. В связи с этим система была укомплектована специально разработанным малобазным датчиком рэлеевских волн. Регистрированные отраженные сигналы в последующем обрабатываются пакетом прикладных программ. Данный преобразователь может быть эффективно использован в задачах контроля накопления повреждений в материале элементов АТ, подвергаемых упруго-пластическим и усталостным воздействиям.Принцип действия системы основан на стробоскопическом эффекте восстановления отраженных импульсов, которые получаются в результате «облучения» материала обследуемого элемента АТ зондирующими импульсами в указанной полосе частот. The study considers some components of technical operation of automotive equipment (at) related to the diagnosis of fuel equipment of internal combustion engines, and for the purpose of non-destructive testing, it is proposed to use ultrasonic and acoustic emission systems for technical diagnostics. It should be noted that when considering the relations showing the relationship between acoustic and physical-mechanical parameters of materials, the time interval is mainly measured, and if the measurement is incorrect, the relationship between the acoustic and physical-mechanical parameters of the material often gives low information content and low accuracy of acoustic methods for determining mechanical characteristics. When developing the technique, the principles of spectral analysis of pulses refl ected from the studied at elements are used, which also support the method of developing both hardware and software for processing the received signals. The results of previous studies suggest that the use of Fourier transforms provides reliable information based on acoustic signals, if the measurement sequence is about 10 seconds. The experience of the system developers shows that the parameters of Rayleigh wave propagation are highly informative. In this regard, the system was equipped with a specially developed low-base relay wave sensor. The registration of refl ected signals is then processed by a package of application programs. This Converter can be effectively used in the tasks of monitoring the accumulation of damage in the material of at elements subjected to elastic-plastic and fatigue effects. The principle of operation of the system is based on the stroboscopic effect of recovery of refl ected pulses, which are obtained as a result of "irradiation" of the material being examined by the at element with probing pulses in the specifi ed frequency band.


2011 ◽  
Vol 337 ◽  
pp. 41-45 ◽  
Author(s):  
Yuan Jing Cai ◽  
Chao Can Zhang ◽  
Li Li Wu ◽  
Run Hua Hu

The synthesis of AGE modified polysiloxane was realized by block copolymerization. Using degradation method and different ratio of raw materials, different content of AGE side chains and molecular weight of AGE modified polysiloxanes had been obtained. AGE modified silicone rubber was prepared by Nano-SiO2and AGE-Modified Polysiloxane Blends. The relationship between the molecular weight of AGE modified polysiloxane, the content of AGE modified side chains and the mechanical properties of AGE modified silicone rubber had been studied. The results showed that AGE modified silicone rubber had better mechanical damping properties than silicone rubber without modification of AGE: lower Tg (-56°C), higher tanδ (0.26), the maximum tensile/rear strengths with appropriate dynamic viscosity (17500mP•s) and the characterization of decreasing tensile/tear strengths with the increasing content of the AGE modified side chains.


2013 ◽  
Vol 575-576 ◽  
pp. 427-433
Author(s):  
Chao Wang ◽  
Jun Xue Ren ◽  
Yu Liu ◽  
Wen Qiang Hao ◽  
Jing Xian Yang

In order to study the performance on silicone rubber elastomer in small-size flexible joint at different temperatures, a series tests for two miniature flexible joints (joint-SR1 and joint-SR2) with the same structure and different formula of silicon rubber elastomer (phenyl silicon rubber and dimethyl silicon rubber) were conducted. Axial compressive stiffness and bending stiffness at various temperatures (-60 °C~20 °C) and vessel pressures (1MPa~8MPa) were studied. Results show that the axial compressive stiffness and bending stiffness of joint-SR1 remain stable throughout the temperature range of-60 °C~20 °C, while those remain stable throughout the temperature range of-40 °C~20 °C and become to be infinite at-50 °C due to the elastic failure of elastomer material for the joint-SR2. Analysis indicates that the reason that elastomer of joint-SR2 lost elasticity at-50 °C is not glass-transition but crystallization. The phenomenon of elastic failure did not appear throughout the temperature range-60 °C~20 °C for the joint-SR1 elastomer is due to the existence of phenyl side-group substitute. The modified chain content of silicone rubber not only affects the process of crystallization inhibition but also the crystallization rate. The rubber with phenyl or other bulky side-group could destroy the crystal of silicone rubber at low temperatures, which is beneficial to be applied in small-size flexible joint.


2014 ◽  
Vol 955-959 ◽  
pp. 1069-1073
Author(s):  
Yan Sheng Du ◽  
Chun Du Wu ◽  
Jin Yu Chu ◽  
Cheng Wu Yi

The welding fume has significant effects on the weld workers’ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was carried out. The purifying device was designed. The relationship between the corona discharge voltage and the purifying efficiency was investigated through experiments with different needle-electrode numbers, different ring-electrode numbers and different needle-plate distances. The results show that 5-needle double-ring electrode has the best efficiency; the purifying efficiency is increase with the lessening of the needle-plate distance and the increase of the discharge voltage. Using 5-needle double-ring electrode, the purifying efficiency reaches its maximum value 97.9% while the needle-plate distance is 6 cm, the discharge voltage is-35 kV. The purifying device has an excellent purifying effect on the welding fume.


2011 ◽  
Vol 48-49 ◽  
pp. 265-269
Author(s):  
Shi Quan Song ◽  
Hua Dong Xu ◽  
Li Hai Wang

In order to carry out non-destructive testing on standing trees, explore the propagation characteristics and the influence factors of the ultrasonic wave spreading in the standing trees. Take simon poplar as the research object, Resistograph were employed to test 30 sample (simon polar) standing trees and it gave a preliminary estimate of the internal defects in the samples, and RSM-SYS5 ultrasonic device were employed to test the ultrasonic propagation velocity spreading in simon poplar standing trees, with the statistics of the ultrasonic propagation velocity spreading separately in the health trees and standing trees with defects, and did a regression analysis of the relationship between the size of the defacts and the ultrasonic propagation velocity. The results show that: 1) When the diameter of sample trees are between 30 and 55cm, the radial velocity of ultrasonic spreading in healthy simon poplar standing trees are in the range of 1029.96m/s ~ 1200m/s, all more than 1000m/s; however, when there are defects in simon poplar standing trees, the ultrasonic radial velocity are less than 1000m/s. 2) The defacts in standing trees have an significant influence on the ultrasonic radial propagation velocity spreading in simon poplar standing trees, defect size and the radial velocity is significantly negatively correlated, and the correlation coefficient R is 0.887.


2011 ◽  
Vol 105-107 ◽  
pp. 1657-1661 ◽  
Author(s):  
Dong Yang ◽  
Wei Zhang ◽  
Ru Liang Yao ◽  
Ben Zheng Jiang

A high temperature vulcanized (HTV) silicone rubber/octavinyl polyhedral oligomeric silsesquioxane (POSS) hybrid was prepared. The micromorphology of the cured hybrid was investigated by scanning electron microscopy (SEM); the thermal degradation stability of this hybrid was studied by means of thermal gravimetric analyses (TGA); the degradation kinetics of this hybrid was also studied using Doyle method and Coats-Redfern method. Results showed that aggregation of self-cross-linked octavinyl POSS appeared in the HTV silicon rubber/POSS hybrid. The incorporation of POSS into silicon rubber networks enhanced the thermal degradation resistance of the matrix. Activation energy derived by the Coats-Redfern method (142.24 kJ/mol) showed a good agreement with the mean value derived by the Doyle method (146.51 kJ/mol); the thermal degradation reaction of the hybrid followed a three-dimensional diffusion law (D4).


2008 ◽  
Vol 589 ◽  
pp. 123-129 ◽  
Author(s):  
István Muka ◽  
Antal Huba

The paper presents the current results of our ongoing research on the field of silicon rubber applications in precision engineering and in medical industry. We have demonstrated two technologies for the manufacturing of precision parts and devices for the medical industry. The mechanical properties of the silicone rubber materials manufactured by press vulcanisation and by moulding (diving) are compared.


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