Influence of Thermal Ageing Process on the Crack Propagation of Rubber Used for Tire Application

2017 ◽  
pp. 351-364
Author(s):  
R. Stoček ◽  
O. Kratina ◽  
P. Ghosh ◽  
J. Maláč ◽  
R. Mukhopadhyay
Keyword(s):  
Crack Propagation ◽  
Thermal Ageing ◽  
Ageing Process

Thermal-ageing characteristics of dry-type transformer epoxy composite insulation

2020 ◽  
Vol 32 (7) ◽  
pp. 741-752
Author(s):  
Yongqiang Wang ◽  
Changhui Feng ◽  
Ruoyu Fei ◽  
Yu Luo
Keyword(s):  
Surface Roughness ◽  
Dielectric Constant ◽  
Surface Morphology ◽  
Epoxy Resin ◽  
Degradation Mechanism ◽  
Three Dimensional ◽  
Thermal Ageing ◽  
Ageing Process ◽  
Complex Dielectric Constant ◽  
Significant Difference

To study the ageing characteristics of epoxy resin composite insulation in dry-type transformers in high-temperature environments, glass fibre-reinforced epoxy resin samples were placed in a hot air ageing environment at 130°C for testing. Dielectric properties, partial discharge (PD), microscopic morphology, three-dimensional morphology and Fourier transform infrared spectroscopy of aged samples were periodically tested. The results show that during the ageing process, the change in the surface morphology of the sample leads to an overall upward trend in surface roughness, and the older the sample, the faster the surface roughness increases; changes in the surface morphology and three-dimensional morphology of the material constitute the basis for judging the condition of the insulating surface and the state of ageing development. Microcracks are the direct cause of debonding of glass fibres and epoxy matrix. Degradation of the sample during the ageing process generates many free radicals, which enhances the polarisation ability of the sample and increases both the dielectric constant and the dielectric loss factor. The real part of the complex dielectric constant is more sensitive to the ageing response of the sample. The older the sample, the greater the effect on the results of the dielectric spectrum test. Since the aged sample generates more hot electrons during the PD process and makes it easier to inject electrons into the material, the PD of the sample is rendered more intense by thermal ageing. There is a significant difference between the degradation mechanism of the thermal ageing and PD. The samples subjected to PD after thermal ageing produce new groups, and the degradation of the samples is more severe than that caused by thermal ageing, or PD, alone.

scholarly journals Enhancement of phenolics content and biological activities of longan (Dimocarpus longan Lour.) treated with thermal and ageing process

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Preaploy Hong-in ◽  
Waranya Neimkhum ◽  
Chanun Punyoyai ◽  
Suwannee Sriyab ◽  
Wantida Chaiyana
Keyword(s):  
Inflammatory Cytokine ◽  
Biological Activities ◽  
Radical Scavenging ◽  
Thermal Ageing ◽  
Seed Extract ◽  
Cytokine Secretion ◽  
Ageing Process ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chemical Compositions ◽  
Dimocarpus Longan

AbstractThis study is the first to compare the chemical compositions and biological activities of a conventional dried Dimocarpus longan with a novel black D. longan that underwent a thermal ageing process. Pericarp, aril, and seed of both D. longan were macerated in 95% v/v ethanol. Their chemical compositions were investigated using a Folin–Ciocalteu assay, aluminum chloride assay, and high-performance liquid chromatography. Antioxidant activities were evaluated in terms of radical scavenging and iron (III) reduction capacity. An enzyme inhibition assay was used to evaluate the hyaluronidase inhibition. Inflammatory cytokine secretion was evaluated with an enzyme-linked immunosorbent assay. After being exposed to a heating and ageing procedure, gallic acid and ellagic acid content were increased tenfold, while the corilagin content was doubled. Black D. longan seed extract was the most potent anti-hyaluronidase and antioxidant with the strongest free radical scavenging and reduction power, while black D. longan aril extract resulted in the highest inhibition of inflammatory cytokine secretion. Black D. longan contained more biologically active compounds and possessed more potent biological activities than conventional dried D. longan. Therefore, thermal ageing treatment is suggested for producing black D. longan, for which seed extract is suggested as a cosmeceutical active ingredient and aril extract for anti-inflammation.

Thermal ageing process at laboratory scale to evaluate the lifetime of Liquefied Natural Gas storage and loading/unloading materials

2013 ◽  
Vol 44 ◽  
pp. 283-290 ◽  
Author(s):  
Florimonde Lebel ◽  
Edmond Abi-Aad ◽  
Benoît Duponchel ◽  
Ingrid Proriol Serre ◽  
Sylvain Ringot ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Storage ◽  
Thermal Ageing ◽  
Liquefied Natural Gas ◽  
Laboratory Scale ◽  
Ageing Process ◽  
Natural Gas Storage

Crack propagation in disordered materials: how to decipher fracture surfaces

2007 ◽  
Vol 32 (1) ◽  
pp. 1-120 ◽  
Author(s):  
L. Ponson
Keyword(s):  
Crack Propagation ◽  
Disordered Materials ◽  
Fracture Surfaces

Neural networks in prediction of thermal ageing effect on oil/paper insulation electrical properties

2005 ◽  
Vol 124 ◽  
pp. 147-151
Author(s):  
L. Mokhnache ◽  
P. Verma ◽  
A. Boubakeur ◽  
R. Kattan
Keyword(s):  
Neural Networks ◽  
Electrical Properties ◽  
Thermal Ageing ◽  
Ageing Effect ◽  
Paper Insulation

Mechanism of irregular crack-propagation in thermal controlled fracture of ceramics induced by microwave

2020 ◽  
Vol 21 (6) ◽  
pp. 610
Author(s):  
Xiaoliang Cheng ◽  
Chunyang Zhao ◽  
Hailong Wang ◽  
Yang Wang ◽  
Zhenlong Wang
Keyword(s):  
Crack Propagation ◽  
Industrial Application ◽  
Ceramic Materials ◽  
Advanced Technology ◽  
Analytical Models ◽  
Propagation Mechanism ◽  
Unstable Crack ◽  
Fracture Simulation ◽  
Initial Stage ◽  
Controlled Fracture

Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.

Sign in / Sign up

Export Citation Format

Share Document