Search results
Results from the WOW.Com Content Network
Ultrasonic hearing is a recognised auditory effect which allows humans to perceive sounds of a much higher frequency than would ordinarily be audible using the inner ear, usually by stimulation of the base of the cochlea through bone conduction. Normal human hearing is recognised as having an upper bound of 15–28 kHz, [1] depending on the person.
An ultrasonic examination. Ultrasound is sound with frequencies greater than 20 kilohertz. [1] This frequency is the approximate upper audible limit of human hearing in healthy young adults.
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.
Sound from ultrasound is the name given here to the generation of audible sound from modulated ultrasound without using an active receiver. This happens when the modulated ultrasound passes through a nonlinear medium which acts, intentionally or unintentionally, as a demodulator .
Ultrasound is applied using a transducer or applicator that is in direct contact with the patient's skin. Gel is used on all surfaces of the head to reduce friction and assist transmission of the ultrasonic waves. Therapeutic ultrasound in physical therapy is alternating compression and rarefaction of sound waves with a frequency of 0.7 to 3.3 ...
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 ...
Galton whistle, the first "dog whistle" A dog whistle (also known as silent whistle or Galton's whistle) is a type of whistle that emits sound in the ultrasonic range, which humans cannot hear but some other animals can, including dogs and domestic cats, and is used in their training.
Ultrasonics deals with sounds at frequencies too high to be heard by humans. Specialisms include medical ultrasonics (including medical ultrasonography), sonochemistry , ultrasonic testing , material characterisation and underwater acoustics ( sonar ).