scholarly journals Application of Acoustic Detection Technology in Offshore Engineering

2016 ◽  
Vol 03 (03) ◽  
pp. 84-90
Author(s):  
新 丛
Keyword(s):  
Acoustic Detection ◽  
Offshore Engineering ◽  
Detection Technology

Fish Bioacoustics and Behavior: Passive Acoustic Detection and the Application of a Closed-Circuit Rebreather for Field Study

2001 ◽  
Vol 35 (2) ◽  
pp. 19-28 ◽  
Author(s):  
Phillip S. Lobel
Keyword(s):  
Behavioral Ecology ◽  
Daily Basis ◽  
Open Circuit ◽  
Acoustic Detection ◽  
Ecological Processes ◽  
Detection Technology ◽  
Scientific Goal ◽  
Species Specific ◽  
Passive Acoustic ◽  
And Behavior

The simple thesis of this paper is that using rebreathers to study fish behavioral ecology, especially bioacoustics, is well worth the expense and additional training required. The scientific goal of my bioacoustic research is to determine which fishes produce species-specific sound patterns exclusively with explicit acts of courtship and mating. This provides scientific insight into evolutionary and ecological processes and also provides data necessary to develop the passive acoustic detection technology for monitoring fish reproduction. When used on a daily basis, rebreathers, in my experience, are economical and as practical as open circuit scuba. This is based both on the costs of diving as well as the efficiency of gathering useful data. The use of open circuit SCUBA while conducting acoustic recordings results in a loss of at least 40% of the data due to the bubble noise from a divers breathing. Rebreathers also provide extended bottom time, especially in shallow water, which enhances a diver's ability to observe fish and gather acoustic-behavioral data.

Acoustic Detection Technology Based on Fiber Bragg Grating Fabry-Perot Interferometer in Liquid Medium

2013 ◽  
Vol 33 (9) ◽  
pp. 0906001 ◽  
Author(s):  
张伟超 Zhang Weichao ◽  
赵洪 Zhao Hong ◽  
刘通 Liu Tong ◽  
王国利 Wang Guoli ◽  
李锐海 Li Ruihai
Keyword(s):  
Liquid Medium ◽  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Acoustic Detection ◽  
Detection Technology ◽  
Fabry Perot

Acoustic detection technology for gas pipeline leakage

2013 ◽  
Vol 91 (4) ◽  
pp. 253-261 ◽  
Author(s):  
Qingqing Xu ◽  
Laibin Zhang ◽  
Wei Liang
Keyword(s):  
Gas Pipeline ◽  
Acoustic Detection ◽  
Detection Technology

scholarly journals An Optical Acoustic Detection System Based on Fabry Pérot Etalon Stability Structure

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1564
Author(s):  
Liyun Wu ◽  
Yongqiu Zheng ◽  
Chenyang Xue ◽  
Jiandong Bai ◽  
Jiamin Chen
Keyword(s):  
Acoustic Waves ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Audio Signal ◽  
High Sensitivity ◽  
Acoustic Detection ◽  
Detection Technology ◽  
Fabry Perot ◽  
Stability Model ◽  
Stability Structure

The optical acoustic detection system based on the Fabry Pérot Etalon (FPE) with high quality–factor (High Q) and stability structure is described and tested. The FPE contains two high–reflectivity Plano–Concave lenses, achieving high fineness and stability. The protective structure of the confocal stabilized FPE is composed of an invar tube, copper sheath, Bakelite sheath and aluminum housing to protect the sensor from the effects of ambient temperature and vibration. The audio signal is injected into the cavity through the sound hole located in the center of the cavity. Acoustic waves induce the vibration of the medium in the cavity, which leads to a simultaneous change in the FPE optical path and a shift of the interference spectrum. The acoustic detection system is built, and the frequency of the laser is locked on the resonant frequency points of the FPE by using phase modulation technology, so as to detect acoustic signals of different frequencies and amplitudes. In addition, the sensitivity of the proposed sensor exceeds 34.49 mV/Pa in the range of 20 Hz–20 kHz. A Signal-to-Noise Ratio (SNR) of 37 dB can be achieved at 20 Hz. Acoustic signal detection technology based on the FPE stability model is used to test the theoretical feasibility of the future high sensitivity Fabry Pérot Interferometric (FPI) acoustic sensors.

scholarly journals Simulation Research on Acoustic Detection Technology of Buried PE Pipes

2021 ◽  
Vol 15 ◽  
pp. 400-409
Author(s):  
Bo Chen ◽  
Jiao Lan ◽  
Liang Ge ◽  
Yunfeng Lu ◽  
Yingbo Hu ◽  
...  
Keyword(s):  
Acoustic Method ◽  
Propagation Rate ◽  
Sine Wave ◽  
Third Party ◽  
Pipeline System ◽  
Acoustic Detection ◽  
Buried Pipe ◽  
Security Risks ◽  
Simulation Research ◽  
Detection Technology

Polyethylene (PE) pipe has been widely used in gas transportation pipeline system because it overcomes the shortcomings of non-corrosion resistance of metal pipelines. However, the stiffness and strength of PE pipe are small, and it is easy to be destroyed in the third-party construction process. Moreover, PE pipe is not electrically or magnetically conductive, and it is unable to use the developed metal pipe detection method, which has brought great security risks. Urban gas pipeline accidents occur frequently, and the situation during the production is complex and severe. Therefore, it is of great significance to study how to effectively realize the detection of underground PE pipe. This paper verifies the feasibility of the acoustic method from the perspective of simulation. Firstly, it studies the influence of buried pipe depth on the received signal of geophone. Secondly, it studies the influence of buried pipe size on the received signal of PE geophone with a certain depth Finally, it studies the received signal of geophone when PE pipe is in mixed soil. The simulation results show that the method based on acoustic wave is suitable, the signal source emits a sweeping frequency single tone sine wave, which propagates to the target and is reflected. A string of geophones on the ground measure the velocity of the surface vibration. Given the propagation rate of wave in the material, time delay can be used between signal sent and received on the ground to obtain the estimated distance to the target.

Analysis of Directional Accuracy of Three Single Arrays

2012 ◽  
Vol 490-495 ◽  
pp. 1714-1717
Author(s):  
Li Qing Fang ◽  
Hong Kai Wang ◽  
Kai Chen
Keyword(s):  
Acoustic Detection ◽  
Advantages And Disadvantages ◽  
Detection Technology ◽  
Array Technology ◽  
Directional Accuracy ◽  
Five Elements ◽  
Element Array ◽  
The One ◽  
Passive Acoustic ◽  
Locating System

Acoustic sensoxr array technology is the one of the key technology of passive acoustic detection technology, whether the single array has a good performance on direction will directly affect the accuracy of the locating system. In order to choose the best single array on direction, in this paper, respectively selected representative plane array and spatial array from a number of typical single arrays to analyze, find out the advantages and disadvantages of two single arrays. On this basis, around the idea of integrating the advantage of symmetric spatial array and plane cross five-element array, according to characteristics of the structure of this two kinds of arrays to design a new locating model—spatial five-element array. And compared with two kinds of single array mentioned above, the results of comparison show that the locating accuracy of spatial five-elements array is superior to both kinds of mentioned, and have high engineering value.

scholarly journals Early Detection of the Wood-boring Insect Semanotus Bifasciatus Using Acoustic Detection Technology

2021 ◽  
Author(s):  
qi jiang ◽  
Yujie Liu ◽  
Lili Ren ◽  
Yu Sun ◽  
Youqing Luo
Keyword(s):  
Pulse Duration ◽  
Early Identification ◽  
Prediction Accuracy ◽  
Time Window ◽  
Larval Instar ◽  
Feeding Activity ◽  
Peak Frequency ◽  
Acoustic Detection ◽  
Detection Technology ◽  
Wood Boring

Abstract BACKGROUND: Semanotus bifasciatus Motschulsky (Coleoptera: Cerambycidae) is one of the most destructive wood-boring pests of Platycladus trees in East Asia, threatening the protection of ancient cypress species and urban ecological safety. Acoustic detection technology has the advantages of high sensitivity, single wood diagnosis and anti-interference, which can be useful for early identification of cryptic wood boring damage. However, there has been limited research on detection time window and acoustics features that suitable for early detection of forest wood borers. METHODS: In this study, we carried out a manipulated insect infestation experiment by inoculating S. bifasciatus into fresh logs, and the feeding sound signals of S. bifasciatus larvae were recorded in timeseries. Then, nine feature variables were selected to characterize the sounds of larval feeding activity. The best time window for acoustic detection during a single day and the whole larval growth stage was determined. And the optimal models for predicting larval instar and population were established using the stepwise regression (SR) and partial least squares regression (PLSR) approach.RESULTS: (1) The single pulse duration of S. bifasciatus was less than 15 ms, and the peak frequency was approximately 8 kHz; (2) Within a 24-hour day, the feeding sound signals were strongest during 13:00 and 20:00; (3) The feeding activity of larvae was greatest during the 1st to the 3rd instar, declined from the 4th instar, and was lowest at the 5th instar; (4) Weak correlations were found between larval instar and feature variables, r ranging from 0.3 to 0.6. By contrast, the larval population has a strong linear correlation with all variables (r>0.7). Except for Average pulse duration and Peak frequency, there indicated high or severe multicollinearity among other variables (the variance inflation factor, VIF >10); (5) The SR model was optimal for predicting larval instar; its prediction accuracy was R2 = 0.71, RMSEp = 0.42, and RPD = 3.38. Average entropy, Peak frequency, and Average pulse duration had the largest influence on the model. (6) The optimal model for predicting population was the PLSR model, and its prediction accuracy was R2 = 0.97, RMSEp = 61.96, and RPD = 28.87. Except for Peak Freq, the other eight variables had a great impact on the model. CONCLUSION: This study highlighted the suitable detection time window and acoustic feature variables for early identification of S. bifasciatus larvae, and optimal models for predicting its larval instar and population were provided. This work will promote further improvements in the efficiency and accuracy of acoustic detection technology for practical applications, providing a reference for evaluating the early damage of wood-boring pest.

scholarly journals Signal Enhancement in Surface Crack Detection with Gas-Coupled Laser Acoustic Detection

2021 ◽  
Vol 40 (4) ◽  
Author(s):  
Dario Vangi ◽  
Mara Bruzzi ◽  
James N. Caron ◽  
Michelangelo S. Gulino
Keyword(s):  
Rayleigh Waves ◽  
Surface Defect ◽  
Crack Detection ◽  
Signal Enhancement ◽  
Inspection Time ◽  
Crack Identification ◽  
Acoustic Detection ◽  
Constructive Interference ◽  
Interference Phenomenon ◽  
Detection Technology

AbstractUltrasonic signal enhancement resulting from constructive interference between direct Rayleigh waves and same waves reflected by a surface defect is exploited to increase crack identification capabilities of the Gas-Coupled Laser Acoustic Detection (GCLAD) non-contact detection technology. Highlights from simulations are provided regarding the interference phenomenon in the solid and its propagation in air, where GCLAD detection occurs. Experimental campaigns are preliminarily performed on a bar to evidence the effect of cracks on the GCLAD acquired signals. Then, a signal enhancement of +30% is reached on a plate, implying that defects are efficiently scanned by moving the GCLAD in proximity of the discontinuity. Since the GCLAD allows monitoring points of a piece belonging to the same line at once, its translation in one direction is sufficient to perform a two-dimensional scan, entailing reduction of inspection time and simple automation of the interrogation layout compared to other traditional or signal enhancement-based techniques.

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