Gas pipe【求确认！】

xp1231

原文：http://www.ornl.gov/info/ornlreview/v35_2_02/pipeline_safety.shtml

根据JJ内容，节选：

Currently, the pipe characterization technique used most by the natural gas industry is the magnetic flux leakage method. This method induces a magnetic field on the walls of the pipe. When a change occurs in the pipe wall geometry as a result of wall thinning, cracks, or pitting, magnetic flux leaks through these areas, and a sensor detects the leakage. The location and amount of leakage indicate the site and size of the flaw.

Venugopal K. Varma, a mechanical engineer in ORNL's Nuclear Science and Technology Division, hopes to integrate novel hardware and software components to improve a flaw detection method that uses electromagnetic acoustic transducer (EMAT) technology. An EMAT device, designed by Pennsylvania State University, would have no contact with the pipeline. It would electromagnetically induce an ultrasonic horizontal shear wave and measure the amount of sound energy reflected from and the amount transmitted through the pipe walls. An algorithm developed by ORNL's Steve Kercel would then recognize differences in patterns of reflected and transmitted sound waves and correlate those differences with changes in the pipe material caused by corrosion, circumferential and axial flaws, and pittings, for example. In this way, the location and size of each flaw (e.g., its length, width, and depth) could be determined.

Thomas Thundat of ORNL's Life Sciences Division is developing a method to detect tiny leaks of gas from pipelines using microcantilever technology. A cantilever is analogous to a microscopic diving board that vibrates at a characteristic rate. If exposed to a pipeline that is not leaking gas, it will vibrate at a rate related to air currents. If it is placed in the vicinity of a gas leak, the frequency of its vibration will change. The shift in frequency may indicate the rush of gas through a pipe crack. The microcantilever sensor will be mounted on the EMAT, enabling the detection of both leaks and flaws in the same pass.

neexd

LZV5

chicheng001

半阙

LZ也很威武~~考过的筒子们都给点力，帮忙确认下哈~~

苏尛涵fiona

有木有考过的来看下呗~