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Статті в журналах з теми "Ultrasonic pulses"

Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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1

Round, W. H., and R. H. T. Bates. "Modification of Spectra of Pulses from Ultrasonic Transducers by Scatterers in Non-Attenuating and in Attenuating Media." Ultrasonic Imaging 9, no. 1 (January 1987): 18–28. http://dx.doi.org/10.1177/016173468700900102.

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When an ultrasonic pulse is scattered off a particle, the spectrum of the scattered pulse differs from that which was transmitted. A mathematical analysis is presented to show that the center frequency of the backscattered pulse is greater than that of the transmitted pulse and that the bandwidth decreases slightly when the spectrum of the pulse is Gaussian in shape. The results of measurements designed to test the theory are presented. The magnitude of the shift in center frequency for pulses backscattered off subwavelength-diameter wires is found to be similar to that predicted by the analysis. It is shown that characteristics of the spectra of the backscattered pulses can differ from those predicted if the shape of the spectrum is not truly Gaussian (as is assumed in most published analyses, including that introduced here). In medical ultrasonic imaging, the pulses are modified by scattering and absorption. The analysis is extended to account for the effects of both interactions. This allows the bandwidth and center frequency of pulses backscattered from tissues and received by medical ultrasonic scanners to be predicted.

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2

MUQAFFI, FAATIH RIFQI, BAMBANG MUKTI WIBAWA, and DARMAWAN HIDAYAT. "Pembangkitan Pulsa Orde Nanodetik Berbasis Mikrokontroler Untuk Eksitasi Transduser Ultrasonik." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 8, no. 1 (January 31, 2020): 229. http://dx.doi.org/10.26760/elkomika.v8i1.229.

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ABSTRAK Makalah ini melaporkan suatu teknik pembangkitan pulsa lebar orde nanodetik (ns) repetitif yang terprogram berbasis mikrokontroler untuk keperluan eksitasi transduser ultrasonik. Pembangkitan pulsa dan pengaturan jarak antar pulsa dilakukan melalui operasi timer mikrokontroler. Sebuah monostable multivibrator mengubah lebar pulsa dari mikrokontroler dalam orde nanodetik melalui pengaturan komponen pewaktuan resistor-kapasitor (RC) dengan cara pengaturan nilai R yang dibuat dari sebuah potensiometer digital. Hasil pengujian menunjukkan bahwa mikrokontroler membangkitkan pulsa repetitif dengan interval terprogram dalam orde 1 detik dan lebar pulsa minimum 1,25 ms. monostable multivibrator dapat mengubah lebar pulsa tersebut menjadi sekitar 140 ns. Berdasarkan hasil pengujian, dapat disimpulkan bahwa sistem berfungsi sesuai rancangan, sistem dapat membangkitkan pulsa repetitif dengan lebar pulsa hingga 140 ns dengan parameter interval dan lebar yang dapat diprogram. Kata kunci: generator pulsa, lebar pulsa singkat, mikrokontroler, monostable multivibrator, eksitasi transduser ultrasonik ABSTRACT This paper reports a repetitive, programmable, microcontroller-based pulse width generation technique for the purpose of ultrasonic transducer excitation. Pulse generation and distance adjustment between pulses is done through the microcontroller timer. A monostable multivibrator changes the pulse width of the microcontroller in the order of nanoseconds by adjusting the resistor-capacitor time constant which are done by adjusting the R value made from a digital potentiometer. The test results show that the microcontroller generates repetitive pulses with programmed intervals in order of 1 second and pulse width of 1.25 ms. A monostable multivibrator converts the pulse width to ca. 140 ns. Based on the test results, it can be concluded that the system functions according to the design as the system can generate repetitive pulses with pulse widths up to 140 nanoseconds with programmable interval and width parameters. Keywords: pulse generator, short-width pulse, microcontroller, monostable multivibrator, ultrasonic transducer excitation

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3

Svilainis, Linas, Vytautas Dumbrava, and Andrius Chaziachmetovas. "Investigation of the Half Bridge and Transformer Push–Pull Pulser Topologies for Ultrasonic Transducer Excitation." Journal of Circuits, Systems and Computers 24, no. 05 (April 8, 2015): 1550062. http://dx.doi.org/10.1142/s0218126615500620.

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Comparison of two high power pulser topologies is presented. Pulser design was aimed for piezoelectric transducer excitation, yet it can also be used for electromagnetic acoustic transducer (EMAT) or capacitive micromachined ultrasonic transducers (CMUTs) excitation. Pulser can produce both single rectangular pulse and trains of rectangular arbitrary duration pulses. In order to achieve the economy of the electrical power consumption and speed both high-pulling and low-pulling elements are active switches. Energy per pulse was used to evaluate the amount of energy consumed. Two topologies were selected for evaluation: transformer output push–pull topology and half bridge output. Experimental investigation results are presented.

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4

Bühling, Benjamin, Stefan Maack, and Christoph Strangfeld. "Enabling multi-input, multi-output measurements with a fluidic transducer." Journal of the Acoustical Society of America 150, no. 4 (October 2021): A349. http://dx.doi.org/10.1121/10.0008547.

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Ultrasonic testing is a widely used method for detecting damage and material characteristics in fields ranging from medicine to aerospace applications. The use of air-coupled ultrasound (ACU) enables an increase in testing speed, since no coupling medium needs to be applied to the transducer-specimen interface at each measurement point. The time needed for testing can be further decreased by using multiple-input, multiple output (MIMO) measurement systems. These systems require the ultrasonic signals to be uncorrelated so the that the individual pulses can be discriminated. Recently, the fluidic transducer was introduced, which generates acoustic pulses in the low ultrasonic frequency range. Experimentally, it is shown that each pulse contains a unique phase signature, that can be extracted by removing the signal envelope information. This technique is used to uniquely discriminate between simultaneously triggered pulses from two fluidic transducers and measure their individual times of flight.

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5

Wolf, J., T. H. Neighbors, and W. G. Mayer. "Optical probing of ultrasonic pulses." Ultrasonics 27, no. 3 (May 1989): 150–54. http://dx.doi.org/10.1016/0041-624x(89)90057-7.

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6

Krymsky, V. V., N. A. Shaburova, and E. V. Litvinova. "Microstructure and Properties of Cast Metal Treated with Electromagnetic Pulses while in Molten State." Materials Science Forum 843 (February 2016): 106–10. http://dx.doi.org/10.4028/www.scientific.net/msf.843.106.

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The results of experiments on the impact of high power electromagnetic pulses (EMP) on the metal alloy melts are discussed. A generator with the following pulse parameters: the amplitude of 10 kV, the duration of 1 ns, the leading edge of 0.1 ns, repetition rate of 1 kHz was used for pulse electric treatment of metal melts. The maximum network input of the generator equals 100 watts. The treatment was carried out in a furnace immediately before casting. The treatment of the melt by electromagnetic pulses is conducted for 10-15 minutes. Comparative analysis of treated and untreated samples showed a change in structure, density, strength, ductility, and toughness of the cast metal. The mechanism of stepping impact on the metal melts was discussed. Analysis of the results of other external physical melt impact methods showed that the overall match is observed with the results of the ultrasonic treatment of metals. Therefore, the hypothesis of the pulse ultrasonic shock wave generation at the front was accepted as the basis-hypothesis for the mechanism of the impact of electromagnetic pulses on the melt. In the theoretical part of the paper a model of electromagnetic pulses conversion in acoustic pulses is proposed.

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7

Feng, Fu Zhou, Chao Sheng Zhang, Qing Xu Min, and Peng Cheng Jiang. "Identification and Reconstruction of Cracks in Ultrasonic Infrared Thermography." Applied Mechanics and Materials 249-250 (December 2012): 46–50. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.46.

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Ultrasonic infrared thermography is a novel nondestructive detection technique, which combines a short ultrasonic pulse excitation and infrared imaging to detect defects, such as crack, in materials and structures. A simplified one-dimension heat-conduction model excited by ultrasonic pulses is put forward in this paper. Based on this model, a serial of image processing methods for recognition and reconstruction of cracks were presented. Results obtained show that the proposed method is creditable and applicable.

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8

Verboven, Erik, Mathias Kersemans, Arvid Martens, Jannes Daemen, Steven Delrue, Koen Van Den Abeele, and Wim Van Paepegem. "Matching Spectroscopy with the Ultrasonic Polar Scan for Advanced NDT of Composites." Proceedings 2, no. 8 (July 19, 2018): 536. http://dx.doi.org/10.3390/icem18-05458.

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The Pulsed Ultrasonic Polar Scan (P-UPS) is a powerful technique for characterizing anisotropic materials like fiber reinforced plastics. A time-domain analysis of the ultrasonic signals yields amplitude and time-of-flight polar diagrams that provide a fingerprint of the local stiffness properties. Though, this simple analysis ignores a lot of information contained in the ultrasonic signals. In this study, we propose to use the P-UPS technique in combination with the spectroscopic analysis of broadband pulses, to obtain plane wave transmission spectra for all in-plane polar angles. This allows us to combine on one hand the strengths of the P-UPS technique, that does not require a priori knowledge about the sample anisotropy, and on the other hand the frequency-domain analysis that utilizes information contained in the broadband pulses.

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9

Cuevas-Acuña, Dulce Alondra, Joe Luis Arias-Moscoso, Wilfrido Torres-Arreola, Francisco Cadena-Cadena, Ramón Gertrudis Valdez-Melchor, Sarai Chaparro-Hernandez, Hisila del Carmen Santacruz-Ortega, and Saúl Ruiz-Cruz. "High-Intensity Ultrasound Pulses Effect on Physicochemical and Antioxidant Properties of Tilapia (Oreochromis niloticus) Skin Gelatin." Applied Sciences 10, no. 3 (February 3, 2020): 1004. http://dx.doi.org/10.3390/app10031004.

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Ultrasonic pulses are considered green technology for the improvement of the functional properties of proteins. In this study, four high-intensity ultrasound pulse treatments (ultrasound-pulsed gelatin (UPG)-42, UPG-52, UPG-71, UPG-84, and non-pulsed control gelatin (CG)) were applied to tilapia (Oreochromis niloticus) skin gelatin in order to study their effect on its physicochemical and antioxidant properties; a non-treated gelatin was used as a control. UPGs showed a significant increase in soluble protein and surface hydrophobicity compared to the control gelatin, and no significant difference was found in the electrophoretic profiles. The effects on the secondary structure were studied by circular dichroism and infrared spectra, and these showed that the random coil conformation was the main component in all treatments and the ultrasonic treatments only affected the α-helix and β-sheet proportion. Finally, the ABTS ((2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (ferric reducing ability) assays demonstrated that ultrasound treatments could improve the antioxidant activity of gelatins as free radical scavengers and electron donors. These results suggest that high-intensity ultrasound pulse technology is useful to improve fish gelatin antioxidant properties, which could be associated with secondary structure disruption.

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10

Sang, Pil, Junseok Heo, Hui Park, and Hyoung Baac. "Photoacoustic Energy Sensor for Nanosecond Optical Pulse Measurement." Sensors 18, no. 11 (November 11, 2018): 3879. http://dx.doi.org/10.3390/s18113879.

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We demonstrate a photoacoustic sensor capable of measuring high-energy nanosecond optical pulses in terms of temporal width and energy fluence per pulse. This was achieved by using a hybrid combination of a carbon nanotube-polydimethylsiloxane (CNT-PDMS)-based photoacoustic transmitter (i.e., light-to-sound converter) and a piezoelectric receiver (i.e., sound detector). In this photoacoustic energy sensor (PES), input pulsed optical energy is heavily absorbed by the CNT-PDMS composite film and then efficiently converted into an ultrasonic output. The output ultrasonic pulse is then measured and analyzed to retrieve the input optical characteristics. We quantitatively compared the PES performance with that of a commercial thermal energy meter. Due to the efficient energy transduction and sensing mechanism of the hybrid structure, the minimum-measurable pulsed optical energy was significantly lowered, ~157 nJ/cm2, corresponding to 1/760 of the reference pyroelectric detector. Moreover, despite the limited acoustic frequency bandwidth of the piezoelectric receiver, laser pulse widths over a range of 6–130 ns could be measured with a linear relationship to the ultrasound pulse width of 22–153 ns. As CNT has a wide electromagnetic absorption spectrum, the proposed pulsed sensor system can be extensively applied to high-energy pulse measurement over visible through terahertz spectral ranges.

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11

TAM, ANDREW, and SAZZADUR CHOWDHURY. "EXPLOITING SONOLUMINESCENCE TO REALIZE A MEMS ULTRASONIC SENSOR." Journal of Circuits, Systems and Computers 17, no. 02 (April 2008): 309–32. http://dx.doi.org/10.1142/s0218126608004290.

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The design of a MEMS ultrasonic sensor has been presented that exploits the Single Bubble Sonoluminescence (SBSL) phenomenon to realize an energy transduction mechanism from acoustical to electrical domain. In the developed scheme, highly stable laser like short duration light pulses are emitted when ultrasound waves strike a thermally generated microbubble stabilized in a confined volume of 1% xenon-enriched water. The emitted light pulses are detected by an integrated profiled silicon type photodetector to generate ultrastable 100 picoseconds duration current pulses per acoustical cycle. The sensor exhibits energy amplification during the transduction process itself that is not achievable by conventional types of MEMS or non-MEMS acoustical sensors. The cylindrical sensor geometry is 650 μm in diameter and 300 μm in height and is designed to have a sensitivity of 5.56 mA/atm/cycle. The sensor can be used in applications where detection of high pressure ultrasound waves is necessary or as an ultrastable very short duration current pulse generator for use in tissue and nerve repair or microsurgery.

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12

Lancaster, W. C., A. W. Keating, and O. W. Henson. "Ultrasonic vocalizations of flying bats monitored by radiotelemetry." Journal of Experimental Biology 173, no. 1 (December 1, 1992): 43–58. http://dx.doi.org/10.1242/jeb.173.1.43.

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Ultrasonic vocalizations of flying bats were effectively monitored with radiotelemetry. We describe a device light enough to be carried by an 11 g bat for periods of up to 1 h. It transmitted signals adequate for fine frequency analysis within a range of approximately 3 m. Telemetry permitted the recording of constant-frequency pulses free from flight-induced Doppler shifts and without time delays. The difference in frequency between telemetered signals and the same signals detected by a remote microphone was used to calculate velocity and Doppler shifts. Pulse emission behavior of Pteronotus parnellii in flight was compared with simulated flight on a pendulum. The data showed significant differences in echo bandwidths, constant-frequency pulse durations and interpulse intervals. In flight, pulses and interpulse intervals tended to be shorter and bats maintained echo frequencies within a significantly narrower band. Phases of echolocation that characterized the approach to a target were clearly evident in flight, but not during pendulum swings. Differences in pulse durations and interpulse intervals may be correlated with the integration of wingbeat, respiration and vocalization. The absence of wing motion in simulated flight changes this integration.

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13

Dwicahyo Pratomo, Ivan, Abdul Rouf, and Tri Wahyu Supardi. "Pengukuran Jarak Lubang Pada Benda Padat Menggunakan Sensor Ultrasonik." IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) 6, no. 1 (April 30, 2016): 81. http://dx.doi.org/10.22146/ijeis.10774.

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AbstrakProses pembuatan benda padat pada umumnya, tidak tercetak dengan bagus sehingga bagian lubang tidak bisa dilihat langsung secara visual. NDT (Non Desctructive Testing) adalah metode untuk mendeteksi lubang serta menguji kualitas benda padat tanpa merusak benda padat tersebut salah satunya menggunakan ultrasonik untuk mendeteksi lubang benda padat yang terdapat pada bagian internal benda padat. Penelitian ini bertujuan untuk merancang bangun alat untuk mengukur jarak lubang pada benda padat menggunakan sensor ultrasonik dan osiloskop.Metode yang digunakan penulis untuk pengujian merupakan metode pulsa pantul yang menghasilkan keluaran berupa amplitudo gelombang yang ditampilkan osiloskop. AFG sebagai masukkan pulsa 40 KHz ke rangkaian penguat kemudian pulsa tersebut dikuatkan transformator dan dilanjutkan ke transmitter ultrasonik. Transmitter mengeluarkan pulsa ke objek dan mengalami pemantulan karena memiliki lubang pada internal bendanya. Pantulan tersebut diterima oleh receiver dan dikuatkan oleh rangkaian penguat kembali, kemudian gelombang ditampilkan pada osiloskop.Penelitian ini menunjukkan bahwa semakin kecil jarak lubang maka amplitudo gelombang yang diperoleh menjadi semakin besar, ketika jarak lubang semakin besar maka nilai koefisien atenuasi bernilai semakin besar juga. Nilai kesalahan pada pengukuran menggunakan alat yang dibuat sebesar 5 %. Kata kunci— ultrasonik, NDT (Non Destructive Testing), pulsa pantul, amplitudo Abstract The process of making solid object in general, not print with good so that holes can’t be seen directly visually. NDT (Non Destructive Testing) is a method for detecting holes and the quality of solid objects without damaging solid object one uses ultrasonic to detect holes a solid object which there are on internal solid object. This research aims to design an instrument for measuring distances holes of solid body using ultrasonic sensor and oscilloscope.The method used for the testing is the echo pulse which produce output of the wave amplitude shown oscilloscope. Function generator as input pulses 40 KHz to circuit amplifier then the transformator strengthened and continued to ultrasonic transmitter. Transmitter generated pulse to object and the pulse has reflection because it has holes an internal object. The reflection pulse is received by the receiver ultrasonic sensor and amplified by signal amplifier circuit, then the wave displayed on oscilloscope. The research showed that the smaller distance holes testing the wave amplitude obtained becomes larger and when the distance holes a solid object is longer the attenuation coefficient value the greater worth. The value of measurement error in using a tool value made author of 5 %. Keywords— ultrasonic, NDT (Non Destructive Testing), echo pulse, amplitude

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14

Ohdaira, Etsuzo, and Masao Ide. "New Model of the Ultrasonic Walking Aid for the Blind." Journal of Robotics and Mechatronics 7, no. 2 (April 20, 1995): 147–50. http://dx.doi.org/10.20965/jrm.1995.p0147.

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A phase difference type ultrasonic walking aid for the blind which uses pulse reflection can be used easily without requiring much difficult training. This new aid features three transducers on the frame of a pair of spectacles. The transducer at the center is for a transmitter, while the transducers on both sides are for receivers. The walking aid detects the distance and direction of an obstacle (target) from the travelling time of ultrasonic pulses transmitted and reflected on the obstacle and the time difference between the pulses reflected from the obstacle and received by their respective receivers. A weak point of an aid of this type is that sometimes slant, flat obstacles such as board fences could not be detected. The new model of the previous aid on which this paper reports overcame this weak point by using plural ultrasonic frequencies. The environment recognition power was improved by this walking aid.

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15

Qiu, Xiao-Feng, Jin-Zhong Xu, Jian-Ming Zhu, Jun-Jie Zhu, Shu Xu, and Hong-Yuan Chen. "Controllable synthesis of palladium nanoparticles via a simple sonoelectrochemical method." Journal of Materials Research 18, no. 6 (June 2003): 1399–404. http://dx.doi.org/10.1557/jmr.2003.0192.

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A simple pulse sonoelectrochemical technique was used to synthesize highly dispersed spherical palladium particles and a dendritic Pd superstructure in the presence of cethyltrimethylammonium bromide (CTAB) at room temperature. The shape and size of spherical nanocrystalline Pd can be controlled by varying current density, the interval between two continuous ultrasonic pulses, ultrasonic intensity, and the concentration of CTAB. The possible growth mechanism of dendritic-structured Pd is discussed.

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16

Wright, O. B. "Ultrasonic generation with ultrashort laser pulses." Review of Laser Engineering 33, Supplement (2005): 156. http://dx.doi.org/10.2184/lsj.33.156.

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17

Send, Wolfgang. "Downstream vorticity measurements from ultrasonic pulses." Journal of Aircraft 25, no. 11 (November 1988): 993–94. http://dx.doi.org/10.2514/3.45693.

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18

Wolf, John W. "Diffraction of light by ultrasonic pulses." Journal of the Acoustical Society of America 84, no. 6 (December 1988): 2290. http://dx.doi.org/10.1121/1.397030.

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19

Imano, K., and H. Inoue. "Technique for generating monopole ultrasonic pulses." Electronics Letters 30, no. 18 (September 1, 1994): 1551–52. http://dx.doi.org/10.1049/el:19941018.

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20

Tomoda, Motonobu, Hiroyuki Matsuo, Osamu Matsuda, Oliver B. Wright, and Roberto Li Voti. "OS02-2-3 Optical tomographic imaging of nanometer ultrasonic pulses propagation." Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2011.10 (2011): _OS02–2–3—. http://dx.doi.org/10.1299/jsmeatem.2011.10._os02-2-3-.

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21

Morimitsu, T., T. Yabuta, T. Tsujimura, and T. Nakayama. "Nondestructive Testing of Resin Mortar Using Ultrasonic Pulses." Journal of Vibration and Acoustics 107, no. 2 (April 1, 1985): 229–34. http://dx.doi.org/10.1115/1.3269249.

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A quick-setting resin mortar has been developed to accomplish a new small diameter shield tunneling method. A nondestructive testing method employing ultrasonic pulses is used for estimating the strength of resin mortar. Young’s modulus, the density, the strength, and the ultrasonic velocity of resin mortar of varying contents are measured. The experimental and theoretical results show the possibility of nondestructive testing of resin mortar strength properties by using ultrasonic pulses.

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22

Liu, Yuchen, Jian Yin, Xutang Tao, Arkady Yartsev, and Pierre-Adrien Mante. "Effect of probe pulse duration in picosecond ultrasonics." Applied Physics Letters 120, no. 20 (May 16, 2022): 202201. http://dx.doi.org/10.1063/5.0093321.

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Picosecond ultrasonics is a powerful tool for nanoscale metrology, giving access to dimensions and mechanical, thermal, and optical properties of nanomaterials. By monitoring the temporal evolution of the interaction of light with coherent acoustic phonons, also known as Brillouin oscillations, phonon lifetime and optical absorption can be measured. However, the extraction of these quantities can be inaccurate due to the common assumption of the infinite coherence length of probe pulses. Here, we demonstrate the effect of probe pulse duration on picosecond ultrasonic measurements numerically and experimentally. We establish a model that shows how the probe coherence length affects the measured signal loss and how we can overcome this limitation and measure an upper limit of the acoustic attenuation factor. The model is verified experimentally on a GaAs bulk substrate by varying the probe pulse duration, showing a strong effect for sub-100 fs pulses. Finally, we applied to CH3NH3PbBr3, where we reveal a high acoustic attenuation factor, which is in line with recent claims of strong anharmonicity in halide perovskites.

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23

Li, Li, Zong Wei Niu, and Guang Ming Yuan. "Effect of Ultrasonic Vibration of Tool on Electrical Discharge Machining of Sintered NdFeB Magnet." Key Engineering Materials 407-408 (February 2009): 628–31. http://dx.doi.org/10.4028/www.scientific.net/kem.407-408.628.

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Sintered NdFeB magnet is widely used in many areas because of its excellent magnet. This paper studies the effect of ultrasonic vibration of tool on electrical discharge machining of it. Experiments were carried out on self-made equipment and material removal rate(MRR) against pulse-on time, MRR versus peak current and machined surface results with and without ultrasonic employment were analyzed. Results show that MRR of the ultrasonic assisted electro-discharge machining would be up to five times higher than MRR of the conventional EDM for small pulse durations and low discharge currents. The machined surface of US/EDM is finer than EDM because of less arcing and short circuit pulses. There are less cracks on the surface.

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24

Mohammad, Iqbal Khan. "Non-Destructive Testing for Concrete: Dynamic Modulus and Ultrasonic Velocity Measurements." Advanced Materials Research 243-249 (May 2011): 165–69. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.165.

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Nondestructive testing (NDT) is a technique to determine the integrity of a material, component or structure. The commonly NDT methods used for the concrete are dynamic modulus of elasticity and ultrasonic pulse velocity. The dynamic modulus of elasticity of concrete is related to the structural stiffness and deformation process of concrete structures, and is highly sensitive to the cracking. The velocity of ultrasonic pulses travelling in a solid material depends on the density and elastic properties of that material. Non-destructive testing namely, dynamic modulus of elasticity and ultrasonic pulse velocity was measured for high strength concrete incorporating cementitious composites. Results of dynamic modulus of elasticity and ultrasonic pulse velocity are reported and their relationships with compressive strength are presented. It has been found that NDT is reasonably good and reliable tool to measure the property of concrete which also gives the fair indication of the compressive strength development.

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25

Khakimov, Ortagoli. "Immersion ultrasonic transducers." Ukrainian Metrological Journal, no. 2 (July 2, 2021): 25–29. http://dx.doi.org/10.24027/2306-7039.2.2021.236076.

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The principles of operation and design of immersion ultrasonic transducers developed by the authors for excitation and reception of elastic vibrations in moving filament-like and plane-parallel materials, in particular, polymer fibbers and films, with an adjustable angle of input (reception) of probing signals into moving controlled object – polymer fibbers and films at normal and high temperatures. The technical characteristics of the installation are given in which the converters developed by us are used, namely, sounding base (distance from the emitter to the receivers), the duration of the probing pulses, the frequency of filling and the duration of the probing pulses, the speed of the controlled object, the combined standard measurement uncertainties of the difference Δt of the propagation times of ultrasonic waves from the emitter to the first and second signal receivers, relative combined standard uncertainties of measurements of attenuation coefficient and velocity of propagation of ultrasonic waves.

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26

VANHILLE, CHRISTIAN, and CLEOFÉ CAMPOS-POZUELO. "SIMULATION OF NONLINEAR ULTRASONIC PULSES PROPAGATING THROUGH BUBBLY LAYERS IN A LIQUID: FILTERING AND CHARACTERIZATION." Journal of Computational Acoustics 18, no. 01 (March 2010): 47–68. http://dx.doi.org/10.1142/s0218396x1000405x.

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This paper deals with the nonlinear propagation of ultrasonic pulses in a homogeneous medium in which a bubbly layer is placed. The medium we use is air bubbles in water. During the propagation of a pulse, the interaction of the acoustic field and bubbles vibration is assured via the coupling of a nonlinear differential system. The solution is tracked in the time domain by means of the SNOW-BL code. In the biphasic fluid, attenuation and nonlinear effects are due to the bubbles only. The study addresses to two applications: filter effects of the layer and nonlinear characterization of liquid–gas mixtures. We study the filter effects (screen effect) a layer has for some frequency ranges present in the initial ultrasonic pulses, in the linear and nonlinear regimes, i.e. for low and high pressure amplitude. One (or several) simple layer is contemplated in numerical experiments with different bubble densities, bubble sizes, layer thicknesses, for different kinds of pulse.

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27

Grzelak, Sławomir, Jarosław Czoków, Marcin Kowalski, and Marek Zieliński. "Ultrasonic Flow Measurement with High Resolution." Metrology and Measurement Systems 21, no. 2 (June 1, 2014): 305–16. http://dx.doi.org/10.2478/mms-2014-0026.

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Анотація:

Abstract The ultrasonic flowmeter which is described in this paper, measures the transit of time of an ultrasonic pulse. This device consists of two ultrasonic transducers and a high resolution time interval measurement module. An ultrasonic transducer emits a characteristic wave packet (transmit mode). When the transducer is in receive mode, a characteristic wave packet is formed and it is connected to the time interval measurement module inputs. The time interval measurement module allows registration of transit time differences of a few pulses in the packet. In practice, during a single measuring cycle a few time-stamps are registered. Moreover, the measurement process is also synchronous and, by applying the statistics, the time interval measurement uncertainty improves even in a single measurement. In this article, besides a detailed discussion on the principle of operation of the ultrasonic flowmeter implemented in the FPGA structure, also the test results are presented and discussed

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28

El Abassi, Dris, Bouazza Faiz, Abderrahmane Ibhi, and Idris Aboudaoud. "Classification of Iron Meteorites with High Frequency Ultrasonic Waves." Journal of Environmental and Engineering Geophysics 24, no. 2 (June 2019): 277–84. http://dx.doi.org/10.2113/jeeg24.2.277.

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Анотація:

We present the results of an ultrasonic pulse-echo technique and its potential to classify iron meteorites into hexahedrites, octahedrites and ataxites by determining their acoustic impedance and phase velocity. Our technique has been adapted from those used in the field of ultrasonic non-destructive investigation of a variety of materials. The main advantage of our technique is that it does not need any preparation of the meteorites like cutting and etching and therefore is rapid, easy and non-destructive. In essence, a broadband acoustic transducer is used in a monostatic pulse-echo configuration which means that both the transducer and the meteorite sample are located in a water bath and adjusted in the way that the ultrasonic pulse shit the meteorite sample at normal incidence. Then the reflected pulses from the front and rear faces of the meteorite sample are measured with the emitting transducer, digitally recorded and processed to analyze the signal. After Fourier transforming the echoed pulses from the front and the rear face of the meteorite sample, the calculated reflection coefficients yield the phase velocity and the acoustic impedance. Our study investigates a variety of iron meteorites collected in Morocco and other countries and it helps to understand how the nickel content of these meteorites affects the acoustic impedance. It reveals that the acoustic impedance of iron meteorites increases with increasing nickel content, so that a further refinement of our technique might have the potential to classify iron meteorites directly and reliably into hexahedrites, octahedrites and ataxites without destroying them.

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29

Ghiculescu, Daniel, Niculae Marinescu, and Ovidiu Alupei. "On Overlapping the Pulses on Cumulative Microjets Stage at Ultrasonically Aided Electrical Discharge Machining." Applied Mechanics and Materials 834 (April 2016): 126–31. http://dx.doi.org/10.4028/www.scientific.net/amm.834.126.

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Анотація:

The paper deals with a solution to increase the machining rate at electrical discharge machining aided by ultrasonics (EDM+US), i.e. the overlapping the voltage pulses provided by EDM generator on the cumulative microjets stage (CMS), which occurs at every final of an ultrasonic period by collective implosion of the gas bubbles from the working gap. This overlapping moves the limit of the removed material by a discharge from the boiling isothermal (at classic EDM) to melting isothermal (at EDM+US) as it is emphasized by the results of finite element analysis. The preliminary experimental data analyzed in the paper are obtained in case of random overlapping at ultrasonic frequency of 20 kHz. They demonstrate an increase of machining rate with more than 300% at EDM+US in comparison with classic EDM in the same working conditions.

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30

Salazar, J., M. J. García, A. Chávez, J. A. Ortega, and A. Turó. "Deconvolution problem to produce ultrasonic short pulses." IEE Proceedings - Science, Measurement and Technology 145, no. 6 (November 1, 1998): 317–20. http://dx.doi.org/10.1049/ip-smt:19982325.

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31

Parygin, Vladimir N. "Collinear filter controlled by variable ultrasonic pulses." Optical Engineering 38, no. 7 (July 1, 1999): 1149. http://dx.doi.org/10.1117/1.602157.

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32

Wolf, J. W., T. H. Neighbors, and W. G. Mayer. "Optical analysis of finite‐amplitude ultrasonic pulses." Journal of the Acoustical Society of America 87, no. 3 (March 1990): 1004–9. http://dx.doi.org/10.1121/1.398826.

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33

Thompson, D. O., and D. K. Hsu. "Technique for generation of unipolar ultrasonic pulses." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 35, no. 4 (July 1988): 450–56. http://dx.doi.org/10.1109/58.4181.

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34

LAURIKS, W., J. THOEN, I. VAN ASBROECK, G. LOWET, and G. VAN DER PERRE. "Propagation of ultrasonic pulses through trabecular bone." Le Journal de Physique IV 04, no. C5 (May 1994): C5–1255—C5–1258. http://dx.doi.org/10.1051/jp4:19945278.

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35

Popovics, Sandor, Joseph L. Rose, and John S. Popovics. "The behaviour of ultrasonic pulses in concrete." Cement and Concrete Research 20, no. 2 (March 1990): 259–70. http://dx.doi.org/10.1016/0008-8846(90)90079-d.

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36

Volkova, A. V., and Yu A. Khrustalev. "Investigation of common salt by ultrasonic pulses." Materials Science 30, no. 2 (1995): 219–22. http://dx.doi.org/10.1007/bf00558576.

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37

Van Den Abeele, K., and O. Leroy. "Probing of ultrasonic pulses by multidirectional light." Ultrasonics 29, no. 6 (November 1991): 464–70. http://dx.doi.org/10.1016/0041-624x(91)90077-l.

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38

Rizkiasari, Anggia Eta, and Abdul Rouf. "Analisis Hubungan Kecepatan Gelombang Dengan Kuat Tekan Beton Menggunakan Metode UPV." IJEIS (Indonesian Journal of Electronics and Instrumentation Systems) 10, no. 1 (April 30, 2020): 11. http://dx.doi.org/10.22146/ijeis.33414.

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Анотація:

Until now the use of concrete as a building material is still widely used for building structures. It is important to do concrete compressive strength testing as one of the factors to know the quality of a concrete. NDT (Non-Destructive Testing) is a method of solid quality testing without damaging the object. Testing with the NDT method is considered more efficient than the destructive test method. One method for performing NDT testing is by utilizing UPV (Ultrasonic Pulse Velocity).UPV is a method for estimating concrete compressive strength based on the ultrasonic pulse velocity relationship through concrete with the concrete compressive strength itself. UPV testing works by emitting ultrasonic pulses of 40 kHz through concrete to obtain the travel time of the pulse. Then the resulting time will be calculated the value of its speed and then will be converted into concrete compressive strength.Concrete compressive strength measurement system for high-quality concrete using UPV method can be designed by utilizing relation between ultrasonic pulse velocity with concrete compressive strength. Based on the test results, the average error value of concrete compressive strength testing is 3.04% with a maximum error of 6.63%.

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39

Rodríguez-Olivares, Noé, José Cruz-Cruz, Alejandro Gómez-Hernández, Rodrigo Hernández-Alvarado, Luciano Nava-Balanzar, Tomás Salgado-Jiménez, and Jorge Soto-Cajiga. "Improvement of Ultrasonic Pulse Generator for Automatic Pipeline Inspection." Sensors 18, no. 9 (September 5, 2018): 2950. http://dx.doi.org/10.3390/s18092950.

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This paper presents the improvement of an ultrasonic pulse generator for a pipeline inspection gauge (PIG), which uses 64 transducers for inspecting distances up to 100 km with an axial resolution fixed at 3 mm and variable speeds between 0 and 2 m/s. An ultrasonic pulse generator is composed of a high-voltage (HV) MOSFETs, driver logic and an HV power supply. We used a DC-HV DC converter device as the HV power supply because it reduces the size of the ultrasound system considerably. However, pipeline geometry and inspection effects such as hammer and shock cause a variable pulse repetition frequency (PRF), producing voltage drops, poor quality of the HV pulse generated, failures in the dimensioning of defects and damage to devices by over-voltage. Our improvement is to implement a control scheme to maintain the high quality of the HV regardless of the variable PRF. To achieve this, we characterized three transfer functions of the DC-HV DC converter, varying the connected load to 10%, 45% and 80%. For the characterization, we used the least squares technique, considering an autoregressive exogenous (ARX) model. Later, we compared three control schemes: (1) proportional-integral-derivative (PID) tuned by simultaneous optimization of several responses (SOSR), (2) PID tuned by a neural network (NN) and (3) PI tuned by the analytical design method (ADM). The metrics used to compare the control schemes were the recovery time, the maximum over-voltage and the excess energy when the shock and hammer effects happen to occur. Finally, to verify the improvement of the HV pulser, we compared the ultrasonic pulses generated for various frequencies and amplitudes using the pulse generator with and without the control scheme.

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40

Dehui, Wu, Yang Jiaxin, Chen Wenxiong, and Wang Teng. "An electromagnetic acoustic transducer with electromagnetic pulse restraining." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 2 (February 1, 2021): 111–17. http://dx.doi.org/10.1784/insi.2021.63.2.111.

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Electromagnetic acoustic transducers (EMATs) are widely used in non-destructive testing (NDT). However, when ultrasonic waves are excited, the transmitting coil generates a strong alternating magnetic field, resulting in the generation of an electromagnetic pulse. To address this problem, an EMAT with electromagnetic pulse restraining is presented in this paper. First, the cause of the electromagnetic pulse is investigated. Second, the conditions for restraining the electromagnetic pulse using the new transmitting coil are analysed. Finally, the design method for the new transmitting coil is provided through evaluation of the magnetic field model of the new transmitting coil. The experimental results demonstrate that the new transmitting coil has a significant effect on the excitation of ultrasonic waves in the tested material and the restraining of electromagnetic pulses. Therefore, the method proposed in this study can self-compensate for the strong alternating magnetic field generated by the transmitting coil, reduce the interference of the electromagnetic pulse with the ultrasonic wave and improve the signal-to-noise ratio (SNR) of EMATs.

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41

He, Ping. "Determination of Ultrasonic Parameters Based on Attenuation and Dispersion Measurements." Ultrasonic Imaging 20, no. 4 (October 1998): 275–87. http://dx.doi.org/10.1177/016173469802000404.

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Анотація:

In the measurement of acoustic attenuation that obeys a power-law α = β f, the traditional through-transmission method uses only the amplitude information of the recorded pulses to determine the two parameters, β and n. In this paper, we propose a new method that utilizes both the amplitude and phase information of the pulses to determine the two parameters. According to this method, the two parameters are estimated by simultaneously performing a least squares fit to the attenuation data that are derived from the amplitude spectra of the pulses, and to the dispersion data that are derived from the phase spectra of the pulses. By fully utilizing the information contained in the recorded pulses and imposing additional constraints on the two parameters, the estimation uncertainty can be reduced. Experimental results from two specimens, one having a linear attenuation and one having a nonlinear attenuation, demonstrate that the new method produces a moderate variance reduction in the case of linear attenuation, and a significant variance reduction in the case of nonlinear attenuation.

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42

Wen, Han, Eric Bennett, and David G. Wiesler. "Shielding of Piezoelectric Ultrasonic Probes in Hall Effect Imaging." Ultrasonic Imaging 20, no. 3 (July 1998): 206–20. http://dx.doi.org/10.1177/016173469802000305.

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This paper addresses significant sources of electromagnetic noise in Hall effect imaging. Hall effect imaging employs large electrical pulses for signal generation and high sensitivity ultrasonic probes for signal reception. Coherent noise arises through various coupling mechanisms between the excitation pulse and the probe. In this paper, the coupling mechanisms are experimentally isolated and theoretically analyzed. Several methods of shielding the probe from electromagnetic interference are devised and tested. These methods are able to reduce the noise to levels below the random thermal noise, thereby improving the signal-to-noise ratio in HEI by two orders of magnitude.

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43

Vergara, L., J. Gosálbez, R. Miralles, and I. Bosch. "On estimating the center frequency of ultrasonic pulses." Ultrasonics 42, no. 1-9 (April 2004): 813–18. http://dx.doi.org/10.1016/j.ultras.2004.01.057.

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44

Levi, Barbara Goss. "Light Comes from Ultrasonic Cavitation in Picosecond Pulses." Physics Today 44, no. 11 (November 1991): 17–18. http://dx.doi.org/10.1063/1.2810317.

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45

Schilt, Carl R., Charlie Escher, and John M. Nestler. "Directional responses of blueback herring to ultrasonic pulses." Journal of the Acoustical Society of America 109, no. 5 (May 2001): 2454. http://dx.doi.org/10.1121/1.4744700.

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46

Hays‐Stang, Kathy J., and Bill D. Cook. "Investigation of ultrasonic pulses with an optical probe." Journal of the Acoustical Society of America 97, no. 4 (April 1995): 2210–17. http://dx.doi.org/10.1121/1.411946.

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47

PhD, Carl D. Latino, Niels Lervad Andersen, and Frands Voss. "Detection of time of arrival of ultrasonic pulses." Journal of Physics: Conference Series 52 (November 1, 2006): 14–26. http://dx.doi.org/10.1088/1742-6596/52/1/002.

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48

Malinaric, Svetozár, and Pavol Kostial. "Contribution to the signal processing of ultrasonic pulses." Journal of Physics D: Applied Physics 31, no. 8 (April 21, 1998): 970–77. http://dx.doi.org/10.1088/0022-3727/31/8/008.

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49

Mückl, Thomas. "Ultrasonic transducer for measuring the travel time of ultrasonic pulses in a gas." Journal of the Acoustical Society of America 100, no. 4 (1996): 1939. http://dx.doi.org/10.1121/1.417867.

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50

Rinkevich, Anatoly B., Olga V. Nemytova, and Dmitry V. Perov. "Comparison of Frequency Features of Pulse Echoes from Different Reflectors." ISRN Mechanical Engineering 2011 (November 15, 2011): 1–8. http://dx.doi.org/10.5402/2011/371514.

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Анотація:

The analysis of interaction of ultrasonic pulses with different reflectors which are located in elastic media is carried out. A parameter which allows estimating the form of reflector is instantaneous frequency of pulse-echo. This parameter is an unsteady pulse echo characteristic. Instantaneous frequency determination algorithm is to use wavelet transformation which has increased noise immunity. It is shown that the instantaneous frequency value for a pulse echo is often shifted from a rated frequency of piezoelectric transducer. Difference between the frequencies extensively depends on the reflector form.

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