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No effect was detected on listeners in the study when only the ultrasonic [14] (frequencies higher than 24 kHz) portion of the test material was played for test subjects; the demonstrated effect was only present when comparing full-bandwidth to bandwidth-limited material.
Ultrasound can also provide additional information such as the depth of flaws in a welded joint. Ultrasonic inspection has progressed from manual methods to computerized systems that automate much of the process. An ultrasonic test of a joint can identify the existence of flaws, measure their size, and identify their location.
The first large scale application of ultrasound was around World War II. Sonar systems were being built and used to navigate submarines. It was realized that the high intensity ultrasound waves that they were using were heating and killing fish. [20] This led to research in tissue heating and healing effects.
This device used piezoelectric transducers to send two ultrasonic waves of differing frequencies toward a point, giving the illusion that the audible sound from their interference pattern was originating at that point. [9] ATC named and trademarked their device as "HyperSonic Sound" (HSS).
The general risks of ultrasound also apply to 3D ultrasound. Essentially, ultrasound is considered safe. While other imaging modalities use radioactive dye or ionizing radiation, for example, ultrasound transducers send pulses of high frequency sound into the body and then listen for the echo.
Another reason why ultrasound is ideal for image guidance is it verifies the acoustic window in real time since it is the same modality as the therapy. [35] The implication of this is that if the target region is not visualized by ultrasound imaging before and during HIFU therapy, then it is unlikely that HIFU therapy will be effective in that ...
Ultrasound energy is transferred based on the frequency and power output of the ultrasonic waves that an ultrasound machine or device creates. Home ultrasound machines and doctor's office machines both operate between 1 and 5 megahertz , however, home machines utilize pulsed ultrasonic waves while professional ultrasound machines in a doctor's ...
The "Laser Ultrasonic" technique is part of those measurement techniques known as "non-destructive techniques or NDT", that is, methods which do not change the state of measurand itself. Laser ultrasonics is a contactless ultrasonic inspection technique based on excitation and ultrasound measurement using two lasers.