scholarly journals Design and experimental research of internal leakage detection device of buried pipeline ball valve based on valve cavity pressure detection

Author(s):  
Mingjiang Shi ◽  
Ting Ye ◽  
Bo Zhou ◽  
Hengli Pu ◽  
Chuan Jiang
2010 ◽  
Vol 37-38 ◽  
pp. 234-237
Author(s):  
Xiao Jing Wang ◽  
Jun Peng Shao ◽  
Guang Bin Yu

In order to improve the low speed stationary of continuous rotary electro-hydraulic servo motor and avoid the pressure impact in the sealed cavity during the oil distributing, this paper designed the shape of buffer groove, established the mathematical model of pressure gradient, and analyzed change law of sealed cavity pressure gradient under different dimension of buffer groove. The pressure field distribution of sealed cavity was studied in certain radial and axial gap, and it is validated the dimension of buffer groove is rational, which lays foundation for structure design and experimental research of large displacement servo motor.


2013 ◽  
Vol 353-356 ◽  
pp. 3067-3071
Author(s):  
Jiao Na Jiao ◽  
Jian Jun Yu

Researches on leak detection system of gas network are significant to fault pipelines diagnosis. In the daily operation of city gas pipeline network, pipeline leakage is the most risky failure type. This paper attempts to review and analyze the existing gas network leak detection systems, meanwhile, design a new kind of leak detection system for daily monitoring and leakage detection of gas network. The greatest advantage of this system is to be able to do all kinds of leak experimental research, especially has great reference value for the leak detection task in colleges and universities.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hailiang Xu ◽  
Jining Qin ◽  
Hehuan Ren ◽  
Jindou Sun ◽  
Lian He

The bearing characteristics of the asphalt pavement structure are greatly influenced by buried pipelines. Improper treatment of buried pipelines would cause early damage to pavement structure. By the digital speckle correlation method (DSCM), the experimental research on bearing characteristics of the asphalt pavement containing buried pipe was carried out. The mechanical characteristics of the asphalt pavement structure are studied under four different pipeline burial conditions. The vertical displacement and strain values of each layer of the asphalt pavement structure are obtained under four operating conditions. The results showed that (1) the digital speckle observation test method can accurately obtain the displacement and strain values of each layer of asphalt pavement structure containing buried pipeline, and the application effect is good. Compared with the traditional contact strain measurement method, this method is simple and accurate and can provide effective analysis data for experimental research. (2) There exists an interlayer effect of the asphalt pavement structure. The vertical displacement value and the strain value are discontinuities and can suddenly change between two adjacent layers. At the same time, the vertical strain and the shear strain concentration phenomenon appear at the bottom of each layer, especially at the bottom of the upper layer and the subbase layer of asphalt. (3) Affected by the buried pipelines, the vertical displacement value of the asphalt pavement structure reduces, and the tensile and shear strain values of asphalt pavement structure increase. The subbase layer of asphalt is most affected by the buried pipelines, which accelerated the destruction of the asphalt pavement structure.


2009 ◽  
Vol 40 (2) ◽  
pp. 55-65 ◽  
Author(s):  
Thomas F. Pettigrew

This paper reviews the evidence for a secondary transfer effect of intergroup contact. Following a contact’s typical primary reduction in prejudice toward the outgroup involved in the contact, this effect involves a further, secondary reduction in prejudice toward noninvolved outgroups. Employing longitudinal German probability samples, we found that significant secondary transfer effects of intergroup contact exist, but they were limited to specific outgroups that are similar to the contacted outgroup in perceived stereotypes, status or stigma. Since the contact-prejudice link is bidirectional, the effect is inflated when prior prejudice reducing contact is not controlled. The strongest evidence derives from experimental research. Both cognitive (dissonance) and affective (evaluative conditioning) explanations for the effect are offered.


1983 ◽  
Vol 28 (10) ◽  
pp. 805-805
Author(s):  
Roger E. Kirk

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