Non-Destructive Detection of GIS Aluminum Alloy Shell Weld Based on Oblique Incidence Full Focus Method

2020 ◽  
Vol 1007 ◽  
pp. 105-110
Author(s):  
Xin Xin Wang ◽  
Cheng He ◽  
Pu Zhi Zhao ◽  
Yi Zheng ◽  
Shi Hao Jiang ◽  
...  
Keyword(s):  
Oblique Incidence ◽  
Near Field ◽  
Calibration Coefficient ◽  
Quantitative Detection ◽  
Imaging Method ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Field Range ◽  
Weld Defects ◽  
Non Destructive

In this paper, a new ultrasonic phased array full focus imaging method based on oblique incidence is proposed to solve the problem of the non-destructive testing of the internal defects in the GIS (gas insulated switchgear) shell welds. By using wedge coupling, the measured weld is far away from the near-field range of the transducer, and the detection angle range can be increased by changing the propagation direction of the acoustic beam. Based on Snell's law, the propagation characteristics of the ultrasonic wave in the interface are studied. On the basis of the conventional ultrasonic array matrix and the full focus imaging algorithm, by introducing the energy attenuation calibration coefficient of the acoustic wave propagation through the wedge, the correction amplitude of the specific focus point p(x, z) is obtained, The non-destructive testing of weld defects of GIS shell in the spot is carried out, and the test results show that the qualitative and quantitative detection of the weld defects can be well realized by using this method.

scholarly journals Lidar Overlap Function Determination Using the Raman Lidar Signals

2020 ◽  
Vol 237 ◽  
pp. 07018
Author(s):  
Jaswant ◽  
Shishir Kumar Singh ◽  
Radhakrishnan S.R. ◽  
Devesh Shukla ◽  
Chhemendra Sharma
Keyword(s):  
Optical Properties ◽  
Simple Technique ◽  
Near Field ◽  
Lower Atmosphere ◽  
Raman Lidar ◽  
Lidar System ◽  
Field Range ◽  
The Mean ◽  
Overlap Factor

The determination of vertical distribution of optical properties of clouds and aerosols using the lidar system is affected by the incomplete overlap between the field of view of transmitter i.e. laser beam & the receiver in the near‐field range. Thus, the study of vertical profiles of aerosol optical properties in the lower atmosphere is erroneous without the correction of lidar overlap function. Here we have analysed the effect of overlap using a simple technique proposed by Ansmann and Wandinger to determine overlap function. We have determined the overlap factor for 5 different days of June 2016 and then calculated the mean overlap profile and determined the relative deviation of each day with respect to mean overlap factor. Results reveal that the complete overlap was achieved beyond 300 meters.

scholarly journals Similarity of the asymmetric swirl generator and a double bend in the near-field range

2019 ◽  
Vol 70 ◽  
pp. 101647 ◽  
Author(s):  
M. Straka ◽  
T. Eichler ◽  
C. Koglin ◽  
J. Rose
Keyword(s):  
Near Field ◽  
Field Range ◽  
Swirl Generator

Contamination and effects of hydrocarbons on the Forth ecosystem, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 327-342
Author(s):  
M. Elliott ◽  
A. H. Griffiths
Keyword(s):  
Deleterious Effect ◽  
Petrochemical Industry ◽  
Near Field ◽  
Toxic Effects ◽  
Organic Enrichment ◽  
Ecosystem Structure ◽  
Intertidal Habitat ◽  
Lethal Effects ◽  
Minimal Impact ◽  
History Of

SynopsisSince 1924 the Forth has received effluent from Scotland's major petrochemical industry and refinery in addition to hydrocarbon inputs from many other sources. The firth shows no major effects of this, but the history of inputs, together with the estuary's physical characteristics, have created a large residue of hydrocarbon contaminants especially in its sediments. This paper gives the degree and gradients of contamination in several components and describes the effect of hydrocarbon contaminants on the ecosystem structure.The major inputs have produced localised lethal effects, in that productive estuarine intertidal habitat has been lost or its functioning altered. The changes are primarily due to organic enrichment with only very near-field toxic effects. Some of the effects result from historical contamination, but existing discharges continue to have a deleterious effect. New petrochemical discharges in both firth and estuary appear to have a minimal impact, although the historical contamination makes it difficult to assess their effects.

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