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In this paper, we describe a 920 MHz band long range wireless SAW passive tag system (WSPTS) for vibration monitoring, which achieves more than 10m reading distance. For the purpose of structural health monitoring (SHM) of aging infrastructures (e.g. bridge, building, and so forth), passive wireless sensor systems are an attractive option because they are operated battery-less and almost maintenance...
Piezoelectric ultrasonic motors (PUMs) are based on the concept of driving the runner by a mechanical vibration excited on the stator via the converse piezoelectric effect. They exhibit merits of small size, simple structure, quick response, high accuracy and resolution, self-locking when power off and a lack of electromagnetic radiation. The linear PUMs become the research focus in recent years as...
Blood clotting, a process to avoid bleeding, involves vasoconstriction, platelet plug build-up, coagulation, clot retraction and fibrinolysis. During coagulation, blood changes from liquid to gel, and the clot viscoelastic properties continue modifying until fibrinolysis. Tests to analyze bleeding disorders and anticoagulant therapy include clot-based assays, to detect the end-point of fibrin network...
Nematic liquid crystal is widely used in optical devices such as liquid crystal displays. The optical characteristics of liquid crystal devices (ex, birefringence) can be controlled by applying an electric field because the liquid crystal molecules have electric dipoles. Although indium tin oxide (ITO) is generally employed as the transparent electrode material, ITO needs the rare metal indium and...
Many high-end power machines demand greater bearing performance in terms of running speed, precision, reliability, longevity, noise reduction, etc. An ultrasonic bearing based on Near-Field Acoustic Levitation (NFAL) effect is a kind of emerging noncontact gas bearing. Due to its self-aligning capability, the ultrasonic bearing can steadily run at a high speed — tens of thousands of revolutions per...
The ultrasonic metal welding method generally uses unidirectional vibration locus. However, this method has different weld strength depending on the direction of welding target installation. To solve this problem, we investigate ultrasonic metal welding by complex longitudinal-torsional vibration which is non-directional vibration. We study focusing on the planar vibration locus among the complex...
Compared with traditional rotary-percussive drill driven by magnetic motors, ultrasonic drill which usually employs the high frequency longitudinal vibration of Langevin transducer to break down rocks, shows advantages of small size, low power, low axial load, and lubrication free, making it available for the extraterrestrial rock sampling, especially for the minor planet with a weak gravitational...
For evaluation of aged concrete structure, it is expected to apply ultrasonic nondestructive measurement. Special coupling media with high viscosity made scanning difficult and the application to huge structure was not practical. Our group prototyped a couplant-free probe realizing strong acoustic coupling using high pressure due to Hertzian contact and found a potential to excite longitudinal wave...
Ultrasonic water treatment is based on the ability of an ultrasonic device to induce cavitation in the liquid, generating physical and chemical effects that can be exploited to produce effective treatment. This requires that the device be both capable of generating high amplitude pressure waves in the treatment volume and capable of treating a large volume of fluid by having a large radiating surface...
A real-time ultrasound (US) coagulation monitoring for coagulation based on acoustic radiation force is described. US imaging to facilitate HIFU has advantages with respect to portability, cost effectiveness and spatiotemporal resolution. Localized motion imaging (LMI) is one of the techniques based on US to detect a change of tissue mechanical properties caused by its thermal coagulation. To achieve...
The non-contact acoustic inspection method has been studied using a laser Doppler vibrometer of high sensitivity and a sound source which can generate big sound pressure at a long distance. However, the inspection at the long distance over 10 m was carried out only with the concrete test object. Therefore, for an actual concrete bridge in Japan, the long distance measurement experiment over 30 m was...
Probe oscillation shear wave elastography (PROSE) can achieve high frame-rate two-dimensional (2D) shear wave elastography by utilizing a continuously vibrating ultrasound probe to simultaneously generate and detect shear waves (Mellema, IEEE TMI 0278-0062). Strategically detecting when the probe returns to the same physical location allowed the shear waves to be decoupled from probe motion artifacts;...
The extremely high frame-rate of ultrafast ultrasound imaging has enabled the possibility to image extremely fast events on the order of thousands of frames/sec. With the success of ultrafast imaging across a wide variety of disciplines, we now explore the ability of ultrafast imaging to capture spinal vibrations for non-invasive spinal testing in living subjects. Previously, we have shown that accelerometer-based...
Epi-optoacoustic (OA) imaging allows flexible clinical use, but out-of-plane and echo clutter from strong OA sources limits contrast. In localized vibration tagging (LOVIT), a focused ultrasonic pushing beam creates transient localized displacement and thus a signal phase shift. Subtraction of OA acquisitions before and at the peak displacement highlights signal from the focus and eliminates out-of-plane...
Nanoparticles have been required in the fields such as medicine, foods and electronic materials. By re-crystallization process, nanoparticles can be formed by quenching a solution. We have generated mono-disperse droplets by using a torsional bolt-clamped Langevin-type transducer and a micropore plate to form fine nanoparticles by quenching the droplets.
A blast furnace surrounded by steel plates from its outer side and by a refractory lining from its inner side is used to acquire pig iron from iron ores. The refractory lining is a wall of refractory bricks which can withstand elevated temperature as high as 1600 degrees. Although the refractory lining has high thermal resistance, it is inevitable for the lining to suffer from degradation of its thickness...
Ultrasound shear wave elastography (SWE) imaging is commercially available on expensive systems. ARF-based shear wave generation requires complex electronics and may induce thermal stress to the tissue. There is need and interest to develop external mechanical vibration (EMV) as a low-cost approach to generate shear waves. Commercial development of mechanical vibration using a single-element transducer...
Contact manipulation using a micropipette is widely used for cell culture and evaluation. However, the operation efficiency and the damage on the cells depend on the individual skills. A technique for manipulating a micro biological material with high accuracy and selectivity is required. Our group has been investigating noncontact ultrasonic manipulation techniques using acoustic standing wave. In...
There are various technologies available for automobile safety. However, about 1.3 million people die each year as a result of road traffic crashes in the world. We aim to develop an impact-reduction device using ultrasonic vibrations that can change the rigidity of crushable zones instantaneously in the event of traffic crashes. We have previously reported on the deformation and impact-reduction...
We have been studied a nondestructive inspection of crack using high-intensity aerial ultrasonic wave and laser Doppler vibrometer(LDV). In this method, cracks are imaged from the vibration velocity distribution including the health part by non-contact measurement of the vibration velocity of the target surface excited by sound wave. Generally, in order to detect cracks, it is necessary to use a high...
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