scholarly journals Comparison between Accelerated Tests and Natural Exposures for Organic Coating Protective Systems Based on EIS Parameters

2021 ◽  
Author(s):  
Xingyue Yong ◽  
Haotian Ji ◽  
Zhenning Chen ◽  
Xin Ruan
Keyword(s):  
Service Life ◽  
Low Frequency ◽  
Mathematical Expression ◽  
Organic Coating ◽  
Atmospheric Environment ◽  
Al Alloy ◽  
Accelerated Tests ◽  
Limit Value ◽  
Protective System ◽  
Probability Density Function Pdf

Abstract The equivalent relationship between accelerated tests and natural exposures has been extensively studied over the past several years to estimate the service life of a barrier organic coating protective system. Herein, based on the probability density function (PDF) theory, a mathematical expression that describes the limit value of the low-frequency impedance (RL) of a barrier organic coating protective system as a function of the elapsed time is proposed in form of Arrhenius formula under certain assumptions, and the degradation coefficient is defined. This expression was consistent with the results of the accelerated tests. The equivalent relationship between accelerated tests and natural exposures, established based on the equivalence principle, was utilized to predict the service life of the coated Al alloy in an ocean atmospheric environment.

scholarly journals Dynamic Line Rating—An Effective Method to Increase the Safety of Power Lines

2021 ◽  
Vol 11 (2) ◽  
pp. 492
Author(s):  
Levente Rácz ◽  
Bálint Németh
Keyword(s):  
Expert System ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Power Line ◽  
Power Lines ◽  
Design Parameters ◽  
Monitoring Methods ◽  
Limit Value ◽  
Potential Applications

Exceeding the electric field’s limit value is not allowed in the vicinity of high-voltage power lines because of both legal and safety aspects. The design parameters of the line must be chosen so that such cases do not occur. However, analysis of several operating power lines in Europe found that the electric field strength in many cases exceeds the legally prescribed limit for the general public. To illustrate this issue and its importance, field measurement and finite element simulation results of the low-frequency electric field are presented for an active 400 kV power line. The purpose of this paper is to offer a new, economical expert system based on dynamic line rating (DLR) that utilizes the potential of real-time power line monitoring methods. The article describes the expert system’s strengths and benefits from both technical and financial points of view, highlighting DLR’s potential for application. With our proposed expert system, it is possible to increase a power line’s safety and security by ensuring that the electric field does not exceed its limit value. In this way, the authors demonstrate that DLR has other potential applications in addition to its capacity-increasing effect in the high voltage grid.

scholarly journals Study on Vibration Tapping for SiCp/Al Particle-reinforced Metal Matrix Composite

2018 ◽  
Vol 228 ◽  
pp. 04005
Author(s):  
Yang Liu ◽  
Jing Zhao
Keyword(s):  
Service Life ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Torsional Vibration ◽  
Metal Matrix ◽  
Low Frequency ◽  
Cutting Fluid

Aiming at answering the question that low tap service life of ordinary tapping and bad thread quality on particle-reinforced metal matrix composite SiCp/Al, the reason of question and the mechanism of low-frequency torsional vibration tapping are analyzed. The experiments were carried out to compare the tap service life and the thread quality of vibration tapping with ordinary tapping without cutting fluid. It indicates that vibration tapping could make tapping torque reduce greatly, the tap service life could be prolonged twice comparing with continuous tapping without cutting fluid, and could ensure the good thread quality. Moreover, it promotes metal matrix composite’s further application.

Dynamic Life Prediction of RC Structures on Multi-Environmental Time Similarity Method

2011 ◽  
Vol 255-260 ◽  
pp. 220-224 ◽  
Author(s):  
Wei Liang Jin ◽  
Zhi Yuan Li ◽  
Ju Chen ◽  
Jin Quan Wang ◽  
Xiao Zhou Wang
Keyword(s):  
Service Life ◽  
Natural Environment ◽  
Life Prediction ◽  
Indoor Environment ◽  
Prior Information ◽  
Service Life Prediction ◽  
Accelerated Tests ◽  
Rc Structures ◽  
Similarity Method

Multi-environmental time similarity (METS) stepped forward for solving the key technique of service-life correlation of reinforced concrete (RC) structures exposed in artificially accelerated and real natural environment. Artificially accelerated tests and the similarity relationship between natural and indoor environment are used to estimate the prior information. Inspections of the real structure and concrete specimens are used to update the information and reduce the uncertainty in the service-life prediction. The progress of service-life prediction becomes dynamic and long-term.

Study on Step Type Vibration Tapping of Superalloy

2014 ◽  
Vol 496-500 ◽  
pp. 401-405
Author(s):  
Feng Qi Han ◽  
Zhi Zun Li ◽  
De Yuan Zhang
Keyword(s):  
Experimental Data ◽  
Service Life ◽  
Torsional Vibration ◽  
Low Frequency ◽  
Spindle Speed ◽  
Cutting Angle ◽  
Step Type

Service life of tap is shorter when low frequency torsional vibration tapping is used to tap on superalloy GH4169. The analysis of experimental data show that excessive repeated cutting times and high friction speed result in rapid wear of tap. In order to avoid above unfavorable factors, step type vibration tapping is proposed, which has larger cutting angle, such as 90°, and lower spindle speed. It was proved by experiments on superalloy GH4169 that service life of tap of step type vibration tapping is about twice of that of common low frequency torsional vibration tapping .

scholarly journals Methods for estimating the durability of the needle bearing of the piston head of the connecting rod of a transportation diesel

2021 ◽  
pp. 55-60
Author(s):  
Vadym Mychaylovich Petuhov ◽  
Alexandr Vasilyevich Orobinsky ◽  
Natalya Anatolyevna Aksenova
Keyword(s):  
Diesel Engine ◽  
Service Life ◽  
Test Procedure ◽  
Operating Conditions ◽  
Accelerated Tests ◽  
Connecting Rod ◽  
Design Work ◽  
Engine Operation ◽  
Piston Head ◽  
Rolling Elements

The article presents the results of an experimental study and analytical evaluation calculations to check service life and increase durability of the needle bearing of piston head of connecting rod of a transport diesel engine. The primary reasons for the violation of the nominal operation of the main units of this mechanism have been established. Corresponding recommendations are proposed for carrying out accelerated tests for durability, reducing the thermal loads of the bearing operation and, as a consequence, improving the quality and service life of its entire piston group. Theoretical and experimental methods for determining the nominal life of the needle bearing of the piston head of the connecting rod (PHCR) of a transport diesel engine are proposed. The theoretical methodology allows obtaining reliable values of durability, taking into account the distribution of the working load over the rolling elements, as well as the mobility of the piston pin and sleeve. The performed calculations make it possible to correct and clarify the standard mathematical model for determining the nominal life of the PHCR needle bearing, depending on the distribution of loads on the rolling elements (rollers) under different operating conditions. This experimental technique with an acceleration factor of 10 is based on a twofold increase in the force effect on the elements of the PHCR needle bearing. This was achieved by assembling the bearing using a special technology, which is described in detail in the work. A significant decrease in the thermal effect and a decrease in radial loads on working rollers have been established. For ensure the regular oil supply into bearing during engine operation, a technique was developed to increase the load on the roller in contact zone, which significantly influenced durability and made it possible to conduct accelerated tests with a reliable yield. Its results of operational research and experience in design work correlate and are sufficiently explained by the developed methods, which allows them to be used for the improvement and modernization of connecting rods with needle bearings in PHCR. That is a permission to use these methodic for doing perfect and modern the needle bearing of the connecting-rod piston. Keywords: diesel, test procedure, needle bearing, rollers, piston head of the connecting rod, durability.

scholarly journals A Color Consistency Processing Method for HY-1C Images of Antarctica

2020 ◽  
Vol 12 (7) ◽  
pp. 1143 ◽  
Author(s):  
Zhijiang Li ◽  
Haonan Zhu ◽  
Chunxia Zhou ◽  
Liqin Cao ◽  
Yanfei Zhong ◽  
...  
Keyword(s):  
Quantitative Evaluation ◽  
Coastal Zone ◽  
Evaluation Method ◽  
Low Frequency ◽  
Color Difference ◽  
Atmospheric Environment ◽  
Global Ocean ◽  
Consistency Results ◽  
New Processing ◽  
Processing Framework

The HY-1C satellite, as part of China’s optical satellite constellation for global ocean monitoring, monitors the ocean and coastal environment by the three broad visible bands of the Coastal Zone Imager (CZI) instrument. However, as a result of the sensor instrument noise, the atmospheric environment during imaging, and the shooting angle, the satellite images often show uneven illumination and inconsistent color between neighboring images. In this paper, according to the characteristics of the HY-1C CZI instrument, we propose a color consistency processing framework for coastal zone images of Antarctica. First of all, the high-frequency and low-frequency information of the image is separated by a statistical filter with simple clustering. The uneven lighting is then replaced by artificial lighting, which is globally uniform. Finally, the color difference between images is corrected by a color transfer method. In order to evaluate the color consistency results quantitatively, a new quantitative evaluation method is proposed. The experimental results for the coastal zone images of Antarctica show that the new processing framework can effectively eliminate the unevenness in the lighting and color. The mosaic results show a good performance in consistent lighting and tones, and the lack of visible mosaic lines proves the effectiveness of the proposed method. The quantitative evaluation analysis confirms the superiority of the proposed method over the Wallis method.

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