China
Africa
Explore chapters and articles related to this topic
Picometer Detection by Adaptive Holographic Interferometry
Published in Klaus D. Sattler, Fundamentals of PICOSCIENCE, 2013
153. Dobbs, E. R. (1973). Electromagnetic generation of ultrasonic waves. Physical Acoustics: Principles and Methods. W. P. Mason and R. N. Thurston, eds. New York: Academic Press, pp. 127-191. Maxfield, B. W. and C. M. Fortunko (1983). The design and use of electromagnetic acoustic-wave transducers (EMATs). Materials Evaluation 41 (12): 1399-1408.
Analysis of elastic wave attenuation in different rock samples
Published in Charlie C. Li, Xing Li, Zong-Xian Zhang, Rock Dynamics – Experiments, Theories and Applications, 2018
X.L. Liu, G.Y. Zhao, J.H. Cui, X.B. Li, Q. Guo
A PCI-2 acoustic emission system and ultra-mini acoustic emission sensor-NANO30 with 140 kHz resonant frequency (Physical Acoustics, USA) were used for signal collection. The parameter settings of the PCI-2 system are listed in Table 1.
The critical slowing-down characteristics of multi-physical field monitoring information about the brittle failure of rock under three-point bending
Published in Nondestructive Testing and Evaluation, 2023
Peng Liang, Zhuang Li, Qun Li, Guangyuan Yu, Shuai Wang, Qiang Han, Xiaohong Huang
The test system mainly includes loading equipment, a full-field strain measurement system, an acoustic emission system, and an infrared thermal image system, which are used to collect multi-field information (Figure 2(a)). The loading equipment is the model TAW-3000 servo-motor control testing machine. The full-field strain device is a VIC-3D full-field strain measurement system. An industrial camera is used to target the surface of the specimen with its sprayed speckle field for collection. Meanwhile, to improve the photo accuracy, LED cold light source is adopted to illuminate the specimen surface. The infrared thermal imaging equipment is the German Infra Tec Image IR 8325, whose detector resolution is 640 × 512 pixels, spectral range is 3.7 to 4.8 μm, and a temperature sensitivity is less than 25 mK (@30). The acoustic emission signal acquisition equipment is PCI 16 multi-channel acoustic emission system of American Physical Acoustics Company. The acoustic emission sensor model is the R6α device, with a resonant frequency of 55 kHz, and the operating frequency ranging from 35 to 100 kHz (Figure 2(b)).
A Neural Network System for Fault Prediction in Pipelines by Acoustic Emission Techniques
Published in Research in Nondestructive Evaluation, 2021
Francesco Noseda, Luiza Ribeiro Marnet, Carlos Carlim, Luiz Rennó Costa, Natanael de Moura Junior, Luiz Pereira Calôba, Sérgio Damasceno Soares, Thomas Clarke, Ricardo Callegari Jacques
We briefly describe the two hydrostatic tests the acoustic-emission data of which were analyzed. In both of these tests, performed according to international technical standards (cf. [19]), a crack was inserted on the surface of a pipe, the pipe was filled with water, and the pressure was slowly increased until failure. Cycles where the pressure was kept constant were interchanged repeatedly with cycles where the pressure was increasing. At each cycle, the pressure was raised by 30 bar, and each cycle took about 10 minute (cf. Figure 1). Acoustic emissions were detected by R15I-AST sensors from Physical Acoustics [7]. The sensors were connected to preamplifiers (40 dB), and the signals were later processed by a Disp 16C equipment, which converted the waveforms into parametric sets.
Experimental study on tensile strength and acoustic emission characteristics of shale exposure to supercritical CO2
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Chao Qin, Yongdong Jiang, Zhipeng Kang, Xiao Song, Hao Liu
Nine shale cylinders with a diameter of 50 mm were cored along the vertical bedding direction in a large shale sample block, and the cored shale cylinders were cut to a thickness of 25 mm. A face grinder was used to grind the bottom and top surfaces to make smooth parallel surfaces. The processed shale specimens were divided into three groups for supercritical CO2 treatment, and each group contained three shale specimens. The treatment conditions (time/pressure/temperature) for three groups were untreated, 15 days/10 MPa/40°C, 30 day/10 MPa/40°C, respectively. The Brazilian splitting test was carried out on the MTS815 all-digital hydraulic servo rigid material testing machine produced in the United States. The axial load was measured by displacement loading during the test, and the loading rate was 0.05 mm/min. To observe the crack initiation and expansion in shale during the mechanical experiment, the DISP series of all-digital acoustic emission monitors produced by the American Physical Acoustics Corporation (PAC) was used to monitor the acoustic emission signals generated in shale in real time during the experiment. The monitoring threshold was set to 40 dB, and the timing parameters were set to PDT = 50 s, HDT = 200 μs, and HLT = 300 μs, respectively.