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1

Wu, Zheng Long, Jie Li et Zhen Yu Guan. « Feature Extraction of Underwater Target Ultrasonic Echo Based on Wavelet Transform ». Applied Mechanics and Materials 599-601 (août 2014) : 1517–22. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.1517.

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Ultrasonic detection has been widely used in underwater detectoscopes as an important method for underwater detection. Feature extraction of echo signal time-delay and amplitude is the main task of processing underwater ultrasonic signal. Underwater target ultrasonic echo signal is influenced by reverberation and noise from the sea and system itself, reverberation interference of signal background is the main difficulty for target echo detection. So we use denoising algorithm to denoise echo signal. At first this paper denoises the measured weighted background clutter data using wavelet threshold denoising method, then the paper extracts breaking points of echo signal through wavelet transform, at last the paper makes an envelope extraction using Hilbert transform combined with wavelet transform methods, and acquires the feature information of echo signal amplitude.
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2

Sonomatic Ltd. « Underwater ultrasonic corrosion mapping system ». NDT International 23, no 1 (février 1990) : 58–59. http://dx.doi.org/10.1016/0308-9126(90)91593-i.

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Sonomatic Ltd. « Underwater ultrasonic corrosion mapping system ». NDT & ; E International 23, no 1 (février 1990) : 58–59. http://dx.doi.org/10.1016/0963-8695(90)90857-f.

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4

Nagashima, Yutaka, Takakazu Ishimatsu et Jamal Tariq Mian. « AUV with Variable Vector Propeller ». Journal of Robotics and Mechatronics 12, no 1 (20 février 2000) : 60–65. http://dx.doi.org/10.20965/jrm.2000.p0060.

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We developed an autonomous underwater vehicle (AUV) with a distributed controller and underwater acoustic communication. It is compact and lightweight thanks to its variable vector propeller and control using sophisticated logic circuits. Control is very precise using underwater ultrasonic command signals. Experiments showed that the AUV moves along a path at the desired position and azimuth. We confirmed the feasibility of our algorithm for increasing ultrasonic communication reliability.
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Widjaja, Raden Sjarief, Dedi Budi Purwanto, Andi Trimulyono et Muhammad Nur Abdullah Hafizh. « Design of Remotely Operated Underwater Vehicle (ROUV) for Underwater Metal Detection ». Kapal : Jurnal Ilmu Pengetahuan dan Teknologi Kelautan 21, no 2 (29 mai 2024) : 73–80. http://dx.doi.org/10.14710/kapal.v21i2.62767.

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The underwater surveys and inspections in Indonesia were carried out mostly by the operation of practical divers who were limited to shallow waters. The deep - sea exploration requires more advanced technology. The development of underwater technology is required to support many functions of underwater surveys and inspections. The purpose of this study was to design a Remotely Operated Underwater Vehicle (ROUV) for detecting objects with metallic materials. The ROV was designed with a Penta Tubular model and camera assistance for navigation, the JSNSR04T ultrasonic sensor to detect object distances, and the LJ12A3 inductive proximity sensor as a metal detector. ROUV rides are controlled using a keyboard with certain keywords and monitored using a smartphone. Testing the JSN-SR04T Ultrasonic sensor uses 5 variations of distance, namely 20cm, 40cm, 60cm, 80cm, and 100cm, with the detection object in the form of a plate with dimensions of 35cm x 35cm. For testing the inductive proximity sensor, the LJ12A3 type uses 3 variations of materials, namely steel plate, aluminum plates as metal objects, and PVC plates as control materials. Tests were carried out in two mediums, namely in air and underwater. Based on the results of data retrieval testing of the ultrasonic distance sensor in the air, the smallest error percentage is 0.06%, and the highest error percentage is 0.705%. In the underwater test, the error percentage was 0.49% for a distance variation of 100 cm. The ultrasonic distance sensor type JSN-SR04 cannot read distance data below 89.75 cm in water due to differences in the speed of sound propagation in different media. The Inductive Proximity Sensor can work well in air and water mediums with 100% accuracy on steel plates, aluminum plates, and PVC plates.
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Hong, Xiaobin, Liuwei Huang, Shifeng Gong et Guoquan Xiao. « Shedding Damage Detection of Metal Underwater Pipeline External Anticorrosive Coating by Ultrasonic Imaging Based on HOG + SVM ». Journal of Marine Science and Engineering 9, no 4 (29 mars 2021) : 364. http://dx.doi.org/10.3390/jmse9040364.

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Underwater pipelines are the channels for oil transportation in the sea. In the course of pipeline operation, leakage accidents occur from time to time for natural and man-made reasons which result in economic losses and environmental pollution. To avoid economic losses and environmental pollution, damage detection of underwater pipelines must be carried out. In this paper, based on the histogram of oriented gradient (HOG) and support vector machine (SVM), a non-contact ultrasonic imaging method is proposed to detect the shedding damage of the metal underwater pipeline external anti-corrosion layer. Firstly, the principle of acoustic scattering characteristics for detecting the metal underwater pipelines is introduced. Following this, a HOG+SVM image-extracting algorithm is used to extract the pipeline area from the underwater ultrasonic image. According to the difference of mean gray value in the horizontal direction of the pipeline project area, the shedding damage parts are identified. Subsequently, taking the metal underwater pipelines with three layers of polyethylene outer anti-corrosive coatings as the detection object, an Autonomous Surface Vehicle (ASV) for underwater pipelines defect detection is developed to verify the detection effect of the method. Finally, the underwater ultrasonic image which used to detect the metal underwater pipeline shedding damage is obtained by acoustic sensor. The results show that the shedding damage can be detected by the proposed method. With the increase of shedding damage width, the effect of pipeline defect location detection is better.
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7

Zhu, Jie, Jia Cheng Guo, Wei Wang et Jia You Wang. « Effect of Arc Current Ultrasonic-Frequency Pulsation on Underwater Wet Arc Welding Quality ». Advanced Materials Research 763 (septembre 2013) : 174–78. http://dx.doi.org/10.4028/www.scientific.net/amr.763.174.

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A novel process of ultrasonic-assisted underwater wet arc welding was proposed to improve the joint properties, a number of ultrasonic-assisted underwater welding experiments were then carried out, and the effects of pulse frequency on weld formation, joint hardness and microstructure were investigated. Experimental results show that the ultrasonic frequency pulsation of arc can improve weld penetration while reducing effectively the hardness of joint HAZ in the arc axial direction and refining the grain of microstructure, and the effects of which are related closely to the pulse frequency.
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8

Nagashima, Yutaka, Nobuyoshi Taguchi, Takakazu Ishimatsu et Hirofumi Inoue. « Development of a Compact Autonomous Underwater vehicle Using Varivec Propeller ». Journal of Robotics and Mechatronics 14, no 2 (20 avril 2002) : 112–17. http://dx.doi.org/10.20965/jrm.2002.p0112.

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This paper describes an autonomous underwater vehicle (AUV) with a distributed fuzzy controller and underwater acoustic communication. Our AUV is made compact and lightweight by using a Varivec propeller and compact controller with sophisticated logic circuits. The AUV is precisely controlled using underwater ultrasonic command signals and fuzzy control. The AUV is autonomously controlled using an electronic compass, collision avoidance sonar, depth sensor, and GPS receiver. Experimental results show that our AUV moved along the target path and held the desired position keeping azimuth direction and depth. We also confirmed that our algorithm to increase the reliability of ultrasonic communication worked without fail.
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9

SHIRAI, Kazuhiro. « Development of Underwater Ultrasonic Positioning System ». Journal of the Marine Acoustics Society of Japan 31, no 4 (2004) : 233–40. http://dx.doi.org/10.3135/jmasj.31.233.

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10

Inoue, Takeshi, et Takatoshi Nada. « Underwater low‐frequency ultrasonic wave transmitter ». Journal of the Acoustical Society of America 83, no 6 (juin 1988) : 2470. http://dx.doi.org/10.1121/1.396290.

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11

ISHIDA, Takehiro, Yuji ISHINO, Masaya TAKASAKI et Takeshi MIZUNO. « Underwater ultrasonic motor with suspended rotor ». Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2022 (2022) : 2A2—M12. http://dx.doi.org/10.1299/jsmermd.2022.2a2-m12.

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12

Smagowska, Bożena. « Ultrasonic Noise Sources in a Work Environment ». Archives of Acoustics 38, no 2 (1 juin 2013) : 169–76. http://dx.doi.org/10.2478/aoa-2013-0019.

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Abstract The use of ultrasonic energy has created versatile possibilities of their applications in many areas of life, especially in hydro location and underwater telecommunications, industry and medicine. The consequence of a widespread use of high intensity ultrasonics in technology is the increased number of people who are exposed to such ultrasonic noise. Therefore it is important to determine the types of machines and other devices that are responsible for the emission of ultrasonic noise (10-40 kHz of central frequencies of one-third octave bands) as harmful and annoying hazard in the work environment. This paper presents ultrasonic noise sources frequently used in industry and preventive measures reducing the exposure to ultrasonic noise. Two types of ultrasonic noise sources have been distinguished: machines and other devices used to carry out or improve production processes, the so-called technological sources and sources in which ultrasonic noise exists as a non-intentional result of operation of many machines and systems, the so-called non-technological sources of ultrasonic noise. The emission of SPL has been determined for each groups of devices based on own measurement results.
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13

Lu, Xiaolong, Zhiwen Wang, Hui Shen, Kangdong Zhao, Tianyue Pan, Dexu Kong et Jens Twiefel. « A Novel Dual-Rotor Ultrasonic Motor for Underwater Propulsion ». Applied Sciences 10, no 1 (19 décembre 2019) : 31. http://dx.doi.org/10.3390/app10010031.

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Micro underwater vehicles (MUVs) have been highlighted recently for underwater explorations because of their high maneuverability, low price, great flexibility, etc. The thrusters of most conventional MUVs are driven by electromagnetic motors, which need big mechanical transmission parts and are prone to being interrupted by the variance of ambient electromagnetic fields. In this paper, a novel dual-rotor ultrasonic motor with double output shafts, compact size, and no electromagnetic interference is presented, characterized, and applied for actuating underwater robots. This motor was composed of a spindle-shaped stator, pre-pressure modulation unit, and dual rotors, which can output two simultaneous rotations to increase the propulsion force of the MUV. The pre-pressure modulation unit utilized a torsion spring to adjust the preload at the contact faces between the stator and rotor. The working principle of the ultrasonic motor was developed and the vibration mode of the stator was analyzed by the finite element method. Experimental results show that the no-load rotary speed and stalling torque of the prototype ultrasonic motor were 110 r/min and 3 mN·m, respectively, with 150 V peak-to-peak driving voltage at resonance. One underwater robot model equipped with the proposed ultrasonic motor-powered thruster could move at 33 mm/s immersed in water. The dual-rotor ultrasonic motor proposed here provides another alternative for driving MUVs and is appropriate for developing specific MUVs when the electromagnetic interference issue needs to be considered.
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14

Wang, Michael Y., Mythili Thevamaran, Michael Sabatini Mattei, Brandon G. Hacha, Gerardo Andres Mazzei Capote, Zongfu Yu, Tim Osswald, Randall H. Goldsmith, Dan J. Thoma et Chu Ma. « Underwater ultrasonic topological waveguides by metal additive manufacturing ». Applied Physics Letters 120, no 14 (4 avril 2022) : 141702. http://dx.doi.org/10.1063/5.0086951.

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Acoustic topological systems explore topological behaviors of phononic crystals. Currently, most of the experimentally demonstrated acoustic topological systems are for airborne acoustic waves and work at or below the kHz frequency range. Here, we report an underwater acoustic topological waveguide that works at the MHz frequency range. The 2D topological waveguide was formed at the interface of two hexagonal lattices with different pillar radii that were fabricated with metal additive manufacturing. We demonstrated the existence of edge stages both numerically and in underwater experiments. Our work has potential applications in underwater/biomedical sensing, energy transport, and acoustofluidics.
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15

Na, Won-Bae, et Tribikram Kundu. « Underwater Pipeline Inspection Using Guided Waves ». Journal of Pressure Vessel Technology 124, no 2 (1 mai 2002) : 196–200. http://dx.doi.org/10.1115/1.1466456.

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Underwater pipeline inspections are conducted using ultrasonic cylindrical guided waves in the laboratory environment. Three different types of mechanical defects—gouge, removed metal, and dent—are fabricated in small-diameter, 22.22-mm, aluminum pipes and tested. To efficiently propagate the antisymmetric (flexural) cylindrical guided waves through the aluminum pipe in water, a new transducer holder device is designed. The device uses commercially available ultrasonic transducers that generate compressional ultrasonic waves in the water. The device can change the striking angle of the incident beam from 0 to 51 deg. With the help of this device, the incident angle adjustment and frequency sweeping can be carried out. This is necessary for obtaining the time history of the received signals for various incident angles and signal frequencies; then these time histories are converted to Vf curves, or received signal amplitude versus frequency curves. From the amplitude of these Vf curves, the type and extent of the mechanical defects can be estimated. This investigation shows that the new coupler device can be effectively used for health monitoring of underwater pipelines using guided waves.
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16

Liu, Zhongzheng, Tao Zhang, Yazhen Yuan, Yuhang Li et Yanzhang Geng. « Evaluation Method for Underwater Ultrasonic Energy Radiation Performance Based on the Spatial Distribution Characteristics of Acoustic Power ». Sensors 24, no 12 (18 juin 2024) : 3942. http://dx.doi.org/10.3390/s24123942.

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In recent years, underwater wireless ultrasonic energy transmission technology (UWUET) has attracted much attention because it utilizes the propagation characteristics of ultrasound in water. Effectively evaluating the performance of underwater ultrasonic wireless energy transmission is a key issue in engineering design. The current approach to performance evaluation is usually based on the system energy transfer efficiency as the main criterion, but this criterion mainly considers the overall energy conversion efficiency between the transmitting end and the receiving end, without an in-depth analysis of the characteristics of the distribution of the underwater acoustic field and the energy loss that occurs during the propagation of acoustic waves. In addition, existing methods focusing on acoustic field analysis tend to concentrate on a single parameter, ignoring the dynamic distribution of acoustic energy in complex aquatic environments, as well as the effects of changes in the underwater environment on acoustic propagation, such as spatial variability in temperature and salinity. These limitations reduce the usefulness and accuracy of models in complex marine environments, which in turn reduces the efficiency of acoustic energy management and optimization. To solve these problems, this study proposes a method to evaluate the performance of underwater ultrasonic energy radiation based on the spatial distribution characteristics of acoustic power. By establishing an acoustic power distribution model in a complex impedance–density aqueous medium and combining numerical simulation and experimental validation, this paper explores the spatial variation of acoustic power and its impact on the energy transfer efficiency in depth. Using high-resolution spatial distribution data and actual environmental parameters, the method significantly improves the accuracy of the assessment and the adaptability of the model in complex underwater environments. The results show that, compared with the traditional method, this method performs better in terms of the accuracy of the acoustic energy radiation calculation results, and is able to reflect the energy distribution and spatial heterogeneity of the acoustic source more comprehensively, which provides an important theoretical basis and practical guidance for the optimal design and performance enhancement of the underwater ultrasonic wireless energy transmission system.
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17

Wang, Hongliang, Yunfei Lv, Chaojie Wang, Xiangjun Wang, Changde He, Chenyang Xue et Shuang He. « Simulation Analysis and Performance Testing Investigation of Capacitive Micromachined Ultrasonic Transducer ». International Journal of Pattern Recognition and Artificial Intelligence 32, no 09 (27 mai 2018) : 1858004. http://dx.doi.org/10.1142/s0218001418580041.

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In various applications of ultrasonic waves, the ultrasonic transducer is the key device of ultrasonic testing and ultrasonic imaging. Compared with the traditional piezoelectric transducer, the capacitive micromachined ultrasonic transducer (CMUT) has many striking advantages, such as low impedance, high bandwidth, easy integration and low cost, and it is expected to become a next generation of mainstream products. In this paper, a CMUT structure for underwater-imaging applications is designed, and the finite element model is established by using COMSOL software, then the modal analysis, harmonic response analysis, electromechanical coupling analysis and transient analysis are carried out. As a consequence, the key parameters of CMUT are obtained, namely resonance frequency, voltage collapse and electromechanical coupling coefficient. For the processed CMUT line array consisting of 16 elements, a test system is built and the emission performance, receiving performance, directivity, bandwidth and preliminary imaging of the designed transducer are tested and analyzed. The results show that the designed CMUT array can meet the requirements of underwater-imaging applications.
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Saotome, Rie, Tran Minh Hai, Yasuto Matsuda, Taisaku Suzuki et Tomohisa Wada. « An OFDM Receiver with Frequency Domain Diversity Combined Impulsive Noise Canceller for Underwater Network ». Scientific World Journal 2015 (2015) : 1–10. http://dx.doi.org/10.1155/2015/841750.

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In order to explore marine natural resources using remote robotic sensor or to enable rapid information exchange between ROV (remotely operated vehicles), AUV (autonomous underwater vehicle), divers, and ships, ultrasonic underwater communication systems are used. However, if the communication system is applied to rich living creature marine environment such as shallow sea, it suffers from generated Impulsive Noise so-called Shrimp Noise, which is randomly generated in time domain and seriously degrades communication performance in underwater acoustic network. With the purpose of supporting high performance underwater communication, a robust digital communication method for Impulsive Noise environments is necessary. In this paper, we propose OFDM ultrasonic communication system with diversity receiver. The main feature of the receiver is a newly proposed Frequency Domain Diversity Combined Impulsive Noise Canceller. The OFDM receiver utilizes 20–28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations. In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described. By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20–30%.
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Suzuki, Hiroshi, Ken-ya Hashimoto et Masatsune Yamaguchi. « ZnO-Film/Si-Diaphragm Underwater Ultrasonic Transducers ». Japanese Journal of Applied Physics 28, S1 (1 janvier 1989) : 63. http://dx.doi.org/10.7567/jjaps.28s1.63.

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20

Chen, Jian, et Zheng Fan. « Ultra-compact ultrasonic metalens for underwater focusing ». Journal of the Acoustical Society of America 146, no 4 (octobre 2019) : 3002–3. http://dx.doi.org/10.1121/1.5137397.

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Hasegawa, Daiki, Hiroshi Inoue et Kenji Murata. « Impulsive Ultrasonic Measurement for Underwater Shockwave Detection ». Japanese Journal of Applied Physics 44, no 6B (24 juin 2005) : 4694–95. http://dx.doi.org/10.1143/jjap.44.4694.

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Charee, W., V. Tangwarodomnukun et C. Dumkum. « Ultrasonic-assisted underwater laser micromachining of silicon ». Journal of Materials Processing Technology 231 (mai 2016) : 209–20. http://dx.doi.org/10.1016/j.jmatprotec.2015.12.031.

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Chen, Bo, et Ji Cai Feng. « A Survey of Underwater Wet Weld Seam Tracking Based on Ultrasonic Sensor ». Applied Mechanics and Materials 433-435 (octobre 2013) : 2227–30. http://dx.doi.org/10.4028/www.scientific.net/amm.433-435.2227.

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With the exploration of marine sources becoming more and more important, underwater welding is widely needed. Because of the special working condition, underwater weld seam tracking technology is urgently needed, for the automation control of the underwater welding process is the inevitable development trend because of the rigorous environment. This paper used ultrasonic sensor to monitor the weld seam position in underwater wet welding process, and signal process algorithm was developed to obtain the weld seam information, experiment results showed that this method could detect the weld seam shape correctly, this load the foundation for further automatically controlling the welding process.
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Lin, Jinuan, et Chu Ma. « Ultrasonic subwavelength imaging with blind structured illumination ». Journal of the Acoustical Society of America 153, no 3_supplement (1 mars 2023) : A29. http://dx.doi.org/10.1121/10.0018042.

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The resolution of ultrasonic imaging systems suffers from the diffraction limit. To solve this problem, we develop a blind structured illumination microscopy (blind-SIM) system that achieves far-field subwavelength resolution in underwater ultrasonic imaging systems. By illuminating the object with multiple structured illumination (SI) patterns generated by scattering media with subwavelength features, the spatial frequency mixing between the object and the SIs converts evanescent waves to propagate waves that can reach sensors in the far field. In this work, the acoustic SIs are generated by randomly distributed micro particles in water. The image of the object is then reconstructed from multiple measurements (each produced by a SI pattern) utilizing computational reconstruction algorithms where the precise knowledge of the SIs is not required. The developed ultrasonic blind-SIM system has the potential in improving the ultrasonic imaging resolution in medical diagnoses, underwater acoustic imaging, and communications. Our system largely reduces the imaging hardware complexity and improves the imaging speed compared with existing ultrasonic subwavelength technologies that mostly rely on the precise localization of time-varying contrast agents.
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Kihara, Sumitaka. « Underwater Ultrasonic Three-Dimensional Measurement and Image Processing for Offshore Underwater Constructions ». IEEJ Transactions on Electronics, Information and Systems 109, no 3 (1989) : 131–38. http://dx.doi.org/10.1541/ieejeiss1987.109.3_131.

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Zhang, Rui, Wendong Zhang, Changde He, Jinlong Song, Linfeng Mu, Juan Cui, Yongmei Zhang et Chenyang Xue. « Design of capacitive micromachined ultrasonic transducer (CMUT) linear array for underwater imaging ». Sensor Review 36, no 1 (18 janvier 2016) : 77–85. http://dx.doi.org/10.1108/sr-05-2015-0076.

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Purpose – The purpose of this paper was to develop a novel capacitive micromachined ultrasonic transducer (CMUT) reception and transmission linear array for underwater imaging at 400 kHz. Compared with traditional CMUTs, the developed transducer array offers higher electromechanical coupling coefficient and higher directivity performance. Design/methodology/approach – The configuration of the newly developed CMUT reception and transmission array was determined by the authors’ previous research into new element structures with patterned top electrodes and into directivity simulation analysis. Using the Si-Silicon on insulator (Si-SOI) bonding technique and the principle of acoustic impedance matching, the CMUT array was fabricated and packaged. In addition, underwater imaging system design and testing based on the packaged CMUT 1 × 16 array were completed. Findings – The simulation results showed that the optimized CMUT array configuration was selected. Furthermore, the designed configuration of the CMUT 1 × 16 linear array was good enough to guarantee high angular resolution. The underwater experiments were conducted to demonstrate that this CMUT array can be of great benefit in imaging applications. Practical implications – Based on our research, the CMUT linear array has good directivity and good impedance matching with water and can be used for obstacle avoidance, distance measurement and imaging underwater. Originality/value – This research provides a basis for CMUT directivity theory and array design. CMUT array presented in this paper has good directivity and has been applied in the underwater imaging, resulting in a huge market potential in underwater detection systems.
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Wang, Zhihao, Wendong Zhang, Renxin Wang, Changde He, Shurui Liu, Jingwen Wang, Zhaodong Li et al. « Investigation of Submerged MEMS Ultrasonic Sensors for Underwater Obstacle Avoidance Application ». Remote Sensing 16, no 3 (28 janvier 2024) : 497. http://dx.doi.org/10.3390/rs16030497.

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Ultrasound is a powerful and versatile technology that has been applied extensively in medicine and scientific research. The development of miniature underwater robots focuses on achieving specific tasks, such as surveys and inspections in confined spaces. However, traditional sonar has limited use in micro underwater robots due to its large size and heavy power demands. Conversely, capacitive micromechanical ultrasonic transducers (CMUTs) offer various advantages, including a wide bandwidth, compact size, and integration feasibility. These attributes make CMUTs a candidate for obstacle avoidance in micro underwater robots. Hence, a novel CMUT structure using Si-Si bonding is proposed. In this design, a membrane isolation layer replaces the cavity bottom isolation layer, simplifying the process and improving bond reliability. A finite element model of the CMUT was constructed in COMSOL and numerically assessed for the CMUT’s operating frequency, collapse voltage, and submerged depth. The CMUT, manufactured using micro-electro-mechanical system (MEMS) technology, undergoes waterproofing with PDMS—A material with similar acoustic impedance to water and corrosion resistance. Underwater tests reveal the CMUT’s resonant frequency in water as approximately 2 MHz, with a −3 dB bandwidth of 108.7%, a transmit/receive beam width of 7.3°, and a standard deviation of measured distance from the true distance of less than 0.05. These outcomes suggest that CMUTs hold promise in obstacle avoidance applications for fish-shaped underwater robots.
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Charee, Wisan, Viboon Tangwarodomnukun et Chaiya Dumkum. « Preliminary Study of Ultrasonic Assisted Underwater Laser Micromachining of Silicon ». Applied Mechanics and Materials 835 (mai 2016) : 139–43. http://dx.doi.org/10.4028/www.scientific.net/amm.835.139.

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The disturbances of vapor bubble to a laser beam in the underwater laser machinig process importantly limits the material removal rate and cut quality obtained. This issue is more essential for the laser micromachining process that a precise and small trench cut is highly needed. In this study, the ultrasound was used to energize and break up the bubble while the laser beam was performing a cut in water. Silicon was used as a work sample in this study as its significant usage in many micro-components. An ultrasonic transducer was located nearby the workpiece in an attempt to vibrate surrounding water. The results revealed that an increase in ultrasonic power increased the width and depth of cut channel. In addition, the workpiece surface obtained after the ablation was clean as similar to that performed by the ultrasonic cleaning. This combination of laser machining and ultrasonic cleaning processes can be another effective approach to cut thermal sensitive materials and also small components whose thermal damage and deposition of cut debris can be harmful to their functionality after laser ablation.
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Duck, Francis. « Langevin’s ultrasonics ». Journal of the Acoustical Society of America 152, no 4 (octobre 2022) : A29—A30. http://dx.doi.org/10.1121/10.0015432.

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Langevin’s work in ultrasonics, which resulted in about twenty publications and patents, will be reviewed. At the beginning of WWI, encouraged by Marie Curie, he started work on a directional ultrasonic system to detect submarines and for underwater communications, based on Chilowski’s proposal. Rejecting whistles, sirens and magnetic sources, he used a large mica ‘singing’ condenser for transmission, and proposed a large area carbon granule microphone as receiver. Noise problems with carbon receivers led Langevin, in early 1917, to test a single large slice of quartz, cut perpendicularly to one of its three electrical axes. This orientation differed from that used by Jacques and Pierre Curie’s quartz pi ezo- électrique, in which the stress and electrical axes are perpendicular. Later that year he demonstrated quartz as a transmitter, creating the enabling technology for later ultrasonic developments. The knowledge was freely disseminated to other Allied laboratories. After the war, Langevin gave the first ever course on theoretical and practical ultrasonics. He facilitated the technological transfer of pulse-echo technology from military to civil sectors and the establishment of a laboratory in Toulon for the certification of ultrasonic transducers. His co-workers went on to study magneto-strictive and high-frequency quartz transducers, therapeutic applications, and finite-amplitude propagation.
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Cobacho-Ruiz, Pablo, Francisco Javier Cañete, Eduardo Martos-Naya et Unai Fernández-Plazaola. « OFDM System Design for Measured Ultrasonic Underwater Channels ». Sensors 22, no 15 (29 juillet 2022) : 5703. http://dx.doi.org/10.3390/s22155703.

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In this paper, we present the development of a multicarrier modulation system of low complexity for broadband underwater acoustic communications (UAC), whose frequency band is located in the ultrasonic range, specifically between 32 kHz and 128 kHz. Underwater acoustic channels are recognized among the most hostile communication channels due to their strong time and frequency selectivity and, hence, the design of high-performance systems is a challenge that is difficult to resolve at the present time with state-of-art technology. The aim of the proposed system is to reach a reasonable bit rate, between 40 and 50 Kbps, over these channels that allows, for instance, the transmission of video signals of limited quality. We describe an orthogonal frequency division multiplexing (OFDM) modem prototype with a parameter setting and design specifically adapted to the channel nature. For this purpose, actual measurements carried out at the Mediterranean sea, on shallow waters, have been used to evaluate the system performance and to optimize the design. A discussion on several modulations and OFDM configurations is presented that leads to the selection of differential and non-differential quadri-phase shift keying (QPSK) as good candidates depending on synchronization capabilities.
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Liu, Chia‐Hung, et Pei‐Tai Chen. « Surface micromachined capacitive ultrasonic transducer for underwater imaging ». Journal of the Chinese Institute of Engineers 30, no 3 (avril 2007) : 447–58. http://dx.doi.org/10.1080/02533839.2007.9671273.

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Lopez-Fernandez, Jesus, Unai Fernandez-Plazaola, Jose F. Paris, Luis Diez et Eduardo Martos-Naya. « Wideband Ultrasonic Acoustic Underwater Channels : Measurements and Characterization ». IEEE Transactions on Vehicular Technology 69, no 4 (avril 2020) : 4019–32. http://dx.doi.org/10.1109/tvt.2020.2973495.

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Lu, Fu-Ming, et Chian-Jen Huang. « Automatic Potato Sorting System in Underwater Ultrasonic Instrumentation ». IFAC Proceedings Volumes 34, no 28 (octobre 2001) : 27–37. http://dx.doi.org/10.1016/s1474-6670(17)32820-3.

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Nowacki, Bartłomiej, Krystian Mistewicz, Sugato Hajra et Hoe Joon Kim. « 3D printed triboelectric nanogenerator for underwater ultrasonic sensing ». Ultrasonics 133 (août 2023) : 107045. http://dx.doi.org/10.1016/j.ultras.2023.107045.

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Pragathi, M., et R. Kumar. « Reduction of Data Transmission Time Delay with Object Detection in Underwater Acoustic Sensor Network ». International Journal of Engineering & ; Technology 7, no 2.24 (25 avril 2018) : 274. http://dx.doi.org/10.14419/ijet.v7i2.24.12063.

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Underwater acoustic sensor networks plays vital role in many applications such as monitoring underwater environment, location and object detection etc., In environment monitoring, the sensor nodes monitors the unwanted obstacles and transmits the information about the obstacles to Base Station(BS). The major problem is when sending data from two or more number of sensor nodes at same time the time delay in data transmission will be increased. In this project, to overcome the problem of end to end delay, mobile data collector is employed with waterproof ultrasonic sensor nodes in underwater acoustic Sensor network.
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36

Remizovsky, І. М. « Little-known facts of the creative way of the outstanding Ukrainian restorer OI Minzhulin : to the problem of restoration of objects of underwater archeology ». Science and Education a New Dimension IX(258), no 47 (25 septembre 2021) : 15–18. http://dx.doi.org/10.31174/send-hs2021-258ix47-03.

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The article highlights little-known facts from the biography and scientific restoration activities of O. Minzhulin, related to the restoration of underwater archeology. The paper describes the first methodology of restoration and conservation of materials of underwater archeological researches of Ukraine initiated by Minzhulin. This methodology involves: This methodology gradually included: placing the lifted objects in an alkaline aqueous solution, applying the method of intensive washing in deionized water, the method of desalination with sesquicarbonate, the method of alkaline-sulfite treatment of iron, the involvement of an ultrasonic device with frequency wave control and more. Innovative were the methods of restoration of underwater archaeological ferrous metal. An underwater volcano is named after the outstanding restorer.
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Rajput, Abhishek, Arun Panchal, Ravi Butola et Jitendra Kumar. « Mechanical and Micro structural Effect of Ultrasonic Welding : Review ». International Journal of Advance Research and Innovation 5, no 2 (2017) : 135–42. http://dx.doi.org/10.51976/ijari.521724.

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Different aspects of Ultrasonic welding is studied, ultrasonic spot welding is widely used under special cases of dissimilar elements, it is a much more efficient, less time consuming and an alternate for Friction stir spot welding(FSSW), ultrasonic spot welded joints are studied for different aspects. Thermal measurements at the interface of ultrasonic spot welding is studied, mechanical performance and grain structure is studied with EBSD examinations. Mechanical properties of Ultrasonicassisted underwater wet welding joints are studied such as bending testing and hardness distribution. Ultrasonic spot welding of Mg alloys and Tin-alloys and temperature measurement at weld interface. A series of ultrasonic spot welding experiments of Mg alloys are studied for weld quality, weld strength and fracture morphologies. A review is done on these following observations studied on Ultrasonic Welding and its various aspects.
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Wu, Cui Qin, Wei Ping Wang, Qi Gang Yuan, Yan Jun Li, Wei Zhang et Xiang Dong Zhang. « Infrared Thermography Non-Destructive Testing of Composite Materials ». Advanced Materials Research 291-294 (juillet 2011) : 1307–10. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1307.

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To detect the delamination, disbond,inclusion defects of the glass fiber composite materials applied in the solid rocket motor, active infrared thermographic non-destructive testing(NDT) is researched. The samples including known defects are heated by pulsed high energy flash lamp. The surface temperature of the samples is monitored by infrared thermography camera. The results of the experiments show that the active infrared thermography technique is a fast and effective inspection method for detecting the defects of delamination, disbond,inclusion of the composites. The samples are also detected by underwater ultrasonic c-scans. The paper concludes that the active infrared thermography NDT is more suitable to rapidly detect the defect in large-area and the underwater ultrasonic c-scans is more suitable to quantitatively identify the defect in local-area.
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Gao, Bizhen, Sai Zhang, Changde He, Renxin Wang, Yuhua Yang, Licheng Jia, Zhihao Wang, Yang Wu, Shumin Hu et Wendong Zhang. « Research on Broadband Matching Method for Capacitive Micromachined Ultrasonic Transducers Based on PDMS/TiO2 Particles ». Micromachines 13, no 11 (26 octobre 2022) : 1827. http://dx.doi.org/10.3390/mi13111827.

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The study of impedance matching between a transducer and its working medium is an important part of acoustic transducer design. The traditional quarter wavelength matching (Q-matching) scheme is not suitable for broadband capacitive micromachined ultrasonic transducers. To mitigate this issue, a 0–3 composite broadband matching layer based on polydimethylsiloxane (PDMS) substrate/TiO2 particles is designed to achieve electrical insulation and efficient acoustic energy transfer of underwater capacitive micromachined ultrasonic transducer (CMUT) devices. In this work, the coherent potential approximation model is used to analyze the properties of 0–3 composite materials. Samples are prepared for performance testing to determine the proportion of TiO2 particles that enable the 0–3 composite materials to have the same longitudinal acoustic impedance as water. The CMUT device is packaged by a spin coating and pouring process, and its performance tests are carried out. The experimental results show that the central frequency of the transducer remains at 1.74 MHz, the −6 dB fractional bandwidth increases from 97.3% to 100.3%, the 3 dB directional main beam width increases from 8.3°to 10.3°, the side lobes decrease significantly, and the device has good reception sensitivity. These values imply that the 0–3 composite material has good matching performance, and this matching scheme has the advantages of high efficiency and wide bandwidth. This broadband matching method endows CMUTs with great advantages in underwater detection systems, and it facilitates underwater ultrasonic imaging of CMUT.
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Song, Changhui, et Weicheng Cui. « Review of Underwater Ship Hull Cleaning Technologies ». Journal of Marine Science and Application 19, no 3 (septembre 2020) : 415–29. http://dx.doi.org/10.1007/s11804-020-00157-z.

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Abstract This paper presents a comprehensive review and analysis of ship hull cleaning technologies. Various cleaning methods and devices applied to dry-dock cleaning and underwater cleaning are introduced in detail, including rotary brushes, high-pressure and cavitation water jet technology, ultrasonic technology, and laser cleaning technology. The application of underwater robot technology in ship cleaning not only frees divers from engaging in heavy work but also creates safe and efficient industrial products. Damage to the underlying coating of the ship caused by the underwater cleaning operation can be minimized by optimizing the working process of the underwater cleaning robot. With regard to the adhesion technology mainly used in underwater robots, an overview of recent developments in permanent magnet and electromagnetic adhesion, negative pressure force adhesion, thrust force adhesion, and biologically inspired adhesion is provided. Through the analysis and comparison of current underwater robot products, this paper predicts that major changes in the application of artificial intelligence and multirobot cooperation, as well as optimization and combination of various technologies in underwater cleaning robots, could be expected to further lead to breakthroughs in developing next-generation robots for underwater cleaning.
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Chu, Dongkai, Xiaoyan Sun, Youwang Hu et Ji-An Duan. « Substrate-independent, switchable bubble wettability surfaces induced by ultrasonic treatment ». Soft Matter 15, no 37 (2019) : 7398–403. http://dx.doi.org/10.1039/c9sm01404g.

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Eke, Zoltán, et István Havasi. « Development of Underwater Surface Measurement : Multibeam Sonar ». Geosciences and Engineering 9, no 14 (2021) : 81–95. http://dx.doi.org/10.33030/geosciences.2021.14.081.

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This study was written in the title theme as a result of the cooperation between the staff of the departments of the two scientific institutions mentioned above. Its first author is also a PhD student of the IGGIS. This year the Bay Zoltán Applied Research Public Benefit Nonprofit Ltd. has purchased a Norbit-iWBMSe multibeam ultrasonic system. The primary purpose of this paper is to describe a multibeam ultrasonic system (Norbit- iWBMSe) and to examine its useful application for mine surveying purposes, particularly for measurements used in underwater mining situations, such as the official determination of the amount of the extracted mineral resources, which also serves as the basis for determining the payable annual mining rent. In our study, first, we will briefly review the new surveying technologies which have appeared in Hungarian mine surveying recently and are likely to be used more and more in the future. Then we will deal with the history of under-water topographic mapping. Afterwards the multibeam sonar survey device and its ad- vantages will be discussed, and two waterbed surveying examples from our own practice will be shown. Finally, the legal background of mining volume computation will be briefly described. Furthermore, it is important to highlight the role of multibeam sonar in mining exploitation process.
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43

Kuyama, Tamio. « New Research Fields of Ultrasonic Electronics and Underwater Acoustics ». Japanese Journal of Applied Physics 29, S1 (1 janvier 1990) : 8. http://dx.doi.org/10.7567/jjaps.29s1.8.

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Song, Jinlong, Chenyang Xue, Changde He, Rui Zhang, Linfeng Mu, Juan Cui, Jing Miao, Yuan Liu et Wendong Zhang. « Capacitive Micromachined Ultrasonic Transducers (CMUTs) for Underwater Imaging Applications ». Sensors 15, no 9 (15 septembre 2015) : 23205–17. http://dx.doi.org/10.3390/s150923205.

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WAKAYAMA, Yuki, et Atsushi SANADA. « Prototype of inexpensive underwater positioning system using ultrasonic waves ». Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2021 (2021) : 1P1—B05. http://dx.doi.org/10.1299/jsmermd.2021.1p1-b05.

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Pistone, Elisabetta, et Piervincenzo Rizzo. « Ultrasonic waves for the inspection of underwater waveguide structures ». Journal of the Acoustical Society of America 132, no 3 (septembre 2012) : 1933. http://dx.doi.org/10.1121/1.4755105.

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Miura, Hikaru, Makoto Takata, Daisuke Tajima et Kenichirou Tsuyuki. « Promotion of Methane Hydrate Dissociation by Underwater Ultrasonic Wave ». Japanese Journal of Applied Physics 45, no 5B (25 mai 2006) : 4816–23. http://dx.doi.org/10.1143/jjap.45.4816.

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Luo, Zhihua, Jun Chu, Lei Shen, Peng Hu, Hongmao Zhu et Lili Hu. « Measurement of underwater vibration by ultrasonic speckle stroboscopic technique ». Measurement 47 (janvier 2014) : 938–45. http://dx.doi.org/10.1016/j.measurement.2013.10.023.

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49

Roh, Y., et B. T. Khuri-Yakub. « Finite element analysis of underwater capacitor micromachined ultrasonic transducers ». IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 49, no 3 (mars 2002) : 293–98. http://dx.doi.org/10.1109/58.990939.

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Burns, D., C. B. Queen et R. C. Chivers. « An ultrasonic signal processor for use in underwater acoustics ». Ultrasonics 23, no 4 (juillet 1985) : 189–91. http://dx.doi.org/10.1016/0041-624x(85)90029-0.

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