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An acoustic Digital MONitor (DMON) has been integrated into a Seaglider autonomous underwater vehicle to serve as a general-use tool for passive acoustic sensing of marine mammal vocalizations. The system is being developed as a complement to conventional ship-based cetacean survey methods. The acoustic system includes three omnidirectional hydrophones, one located on centerline of the aft payload...
This paper presents an ultrasonic thermometry state of the art study and shows principle of the ultrasonic thermometry through experiments with an ultrasonic thermometer prototype. The study covers a brief ultrasonic temperature measurement research history and focuses on recent revelations in this field. The thermometer prototype is constructed to be portable and usable for educational presentations...
In this paper, we find conditions that reconstruction of temperature distribution gets worse when the ultrasonic transceivers (transmitter and receiver) are arranged flexibly. We discovered the minimum number of the ultrasonic transceivers required for successful reconstruction and proved that the number is correct. Moreover, we proposed arrangement of the number in accordance with parity of pixel...
Electromagnetic [1] and acoustic [2] metamaterials that exhibit linear dispersion at a nonzero frequency and a wave vector (k) of zero, leading to a conical dispersion surface or so-called Dirac cone dispersion, have been demonstrated recently. These materials display unusual behavior associated with the occurrence of a finite group velocity at k = 0, leading to a wave which propagates with a uniform...
For new-generation thermal power plants, off-line non-destructive testing is not sufficient and long-term monitoring at high temperature is desired. In the previous study, ultrasonic transducers made by CaBi4Ti4O15 (CBT)/Pb(Zr, Ti)O3 (PZT) were investigated and maximum operation temperature was estimated as ∼600°C. Since operation temperature of new-generation thermal power plant will be ∼700°C, it...
Laser-generated focused ultrasound (LGFU) is a promising modality for micro-precision therapy, relying on cavitation-induced mechanical disturbance. However, conventional LGFU systems still require a high laser energy (several to tens of mJ/pulse), irradiated onto an optoacoustic lens, to generate a focal pressure sufficient for acoustic cavitation at focus. Acoustic attenuation over the tissue depth...
In many industrial technological processes, liquids are subjected to high pressures, e.g., in the high pressure food preservation. Similarly, in modern fuel injection systems for diesel engines, biofuel is subjected to a pressure up to 300 MPa. In such conditions, in liquids, high-pressure phase transitions (solidification) can occur that substantially increase the density and liquid viscosity. This...
In order to study relaxation characteristics of viscoelasticity of the liquid, a wide frequency sweep in the range of MHz to GHz is desired. We, therefore, report a new type HBAR (High-overtone Bulk Acoustic Resonator: shear mode ScAlN film on AT-cut quartz plate) sensor which makes it possible to operate in a wide frequency range as shown in Fig. 1. When a thickness shear acoustic mode (TSM) resonator...
In many industrial technological processes, liquids are subjected to high pressures, e.g., in the high pressure food preservation. Similarly, in modern fuel injection systems for diesel engines, biofuel is subjected to a pressure up to 300 MPa. In such conditions, in liquids, phase transitions can occur that substantially increase the density and liquid viscosity. This can be very detrimental for...
Accurate measurement of acoustic dispersion has important applications in theoretical acoustics, ultrasound tissue characterization, ultrasound measurement systems, etc. Usually, the parameter of interest associated to dispersion is the variation in the propagation velocity as a function of the frequency or the temperature. Nevertheless, this work is focused on the study of the variation in the propagation...
This paper presents an efficient method to measure physical parameters of thin elastic layers by using an air-coupled ultrasound technique. In the method, surface densities of elastic thin layers are approximated through solely non-contact measurement of through-transmission of ultrasonic signals. A copper foil and a copper foil coated with carbon composite on both sides are used to experimentally...
Off-line ultrasonic non-destructive testing (NDT) is used to inspect defects in thermal power plants. However, for new-generation thermal power plants, off-line NDT is not sufficient and long-term monitoring at high temperature is desired. In the previous study, ultrasonic transducers made by CaBi4Ti4O15 (CBT)/Pb(Zr, Ti)O3 (PZT) were investigated and maximum operation temperature was estimated as...
Nonlinear ultrasonic measurements has been proposed to characterize the creep damage evolution of P92 martensitic ferritic steels at a temperature of 650 °C and stresses of 100 MPa and 115 MPa, respectively. The correlation of increase-decrease-increase between the ultrasonic nonlinearity and the creep strain was achieved for both sets of specimens. Considering the metallographic studies, nonlinear...
Low intensity pulsed ultrasound (LIPUS) is a therapy used clinically for bone fracture and soft tissue healing LIPUS induces functional alterations in cell behavior and has shown potential for cancer therapy. In order to understand the underlying biophysical mechanisms, the ability to control acoustic exposure parameters and elimination of unwanted effects such as the formation of standing wave patterns,...
The testing guideline of medical measuring devices on ultrasonic physiotherapy equipment is published in Thailand, which is conducted under a collaborative project between the ultrasound laboratory of the National Institute of Metrology, Thailand (NIMT) and the department of medical sciences, and the department of health service support, ministry of public health. This project has been carried out...
Touchscreen sensors are widely used in many devices such as smart phones, tablets, laptops, etc. There are many different types of modalities that enable sensing the touch. The dominant technologies on the market are the capacitive, resistive, acoustic or ultrasound, and optical touch systems. None of these technologies are perfect and each has some advantages and disadvantages. Capacitive touch technologies...
P92 martensitic ferritic steels are an attractive material for critical components in power industries due to the excellent creep property. However, these steels are usually susceptible to creep strength degradation during a long service period under the elevated temperature and pressure. Creep damage evaluation is of concern to quantitatively assess the remaining lifespan of the critical components...
Selective application of shear forces on cells triggers stimulatory biological effects resulting in the manipulation of the cellular mechano-environment and the alteration of cell behavior. The acoustic radiation force (ARF) induced by focused ultrasound (FUS) can generate shear forces as in shear wave elastography imaging. The commonly used setups for in-vitro studies of ultrasound-induced mechanotransduction...
The development of a hybrid sensor consisting of a piezo acoustic resonator and a semiconducting humidity sensor for measurements of the dielectric break down voltage (BDV) in insulating oils of transformers “on the grid” and online, to ensure flawless operation of both the transformer and the powering grid.
The presence of water in lubricating oil is destructive even in very small quantities. The ultrasonic measurement is an alternative method to find a solutions for detecting and measuring the water contamination in the lubricant oil. The amount of water contamination in lubricating oil will affect the velocity of wave propagation in the lubricant. In this study, a 2.25 MHz ultrasonic wave is propagated...
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