Questions tagged [ultrasound]

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Hydrophone for laboratory/tank use

I am looking for a reference hydrophone that has a linear frequency response in the frequency range from10kHz to little above 500kHz. Should have a good sensitivity. I have found some manufacturers ...
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Ultrasonic diffraction

When ultrasonic is applied to a liquid it creates an acoustic grating in which some part have more refractive index and some part have low refractive index. When light is passed through this grating ...
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Why is there no phase shift between pressure and displacement in spherical sound waves?

I know this question was already stated, but for me it didn't provide an intuitive answer. So can someone elaborate why there is no phase shift between displacement and sound pressure close to the ...
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Waves and oscillation [duplicate]

Maxima and and minima of sound wave at given time represents air density (maxima represents compression) similarly. How does these curved lines over the water surface represent variation of air ...
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Is low frequency sound slower (in air)?

Does sound in air experience dispersion? In other words, is the group velocity of sound higher for higher frequencies or the other way round? Is this difference substantial enough to be noticed/heard? ...
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If ultrasonic waves have such large wavelengths, then how can they be used to sense such small details?

We use the properties of waves for sensing. This includes electromagnetic waves, such as in lasers, but also mechanical waves, such as sound. And one of the primary factors that determine how useful a ...
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How would one calculate the electric field produced by a piezoelectric device in response to a sound wave?

So the governing equations of piezoelectricity are: Where E is the electric field, D is the displacement field, S is the strain, and T is the stress. Say I have a piezoelectric device where the ...
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Are microdroplets as good or better than liquids as coolants?

Well, I don't understand much about physics and such, so I hope I don't make too many misconceptions. So, from what I heard, gases in general aren't as good coolants as liquids because they aren't ...
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Penetrating sound through wall [closed]

I'm an electronics engineer, sorry for my lack of physics knowledge. I need an inaudible sound transmitter that can penerate through one concrete wall. Is that possible such a thing? By the way my ...
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Measuring longitudinal and transverse (shear) waves speed in glass substrates

Let say I have a $500-1000 \ \mathrm{microns}$ thick glass substrate. How can I experimentally measure the longitudinal and transverse wave speed in this substrate? I can either attach a piezo disk to ...
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Higher order nonlinear ultrasonic signals

With nonlinear ultrasound, the higher harmonic frequencies are used, for example, to identify defects in materials. Usually the second and third harmonic frequencies are used. If higher orders are ...
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How sparse does air have to get before the speed of sound slows dramatically? Or ceases altogether?

Supposedly, at low altitudes, the increase in the speed of sound due to the increased pressure of air (and therefore, compressibility?) almost exactly cancels out the decrease in sound velocity due to ...
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Longitudinal wave propagation in 3D

When a longitudinal wave is sent through a body, there is a strain in the emitted direction (x). What about the three-dimensional body with the strains in the direction perpendicular to the emitting ...
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Speed of sound in a solid calculated theoretically

I am trying to find theoretically precise values of the speed of sound in various solid materials. I have found the CRC Handbook of Chemistry and Physics with a table of values with no uncertainties ...
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Through-metal-wall Ultrasound sensor imaging?

A while ago, MIT published a paper that used a radar sensor to take a low-res image, and then they trained an AI model to convert the image into a human skeleton for through-wall human pose detection. ...
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Intensity of ultrasound emitter

I do an extraction of fir tree needles in water. The endings of branches with needles (4400 pounds) is placed on three levels of net in cylindrical container (6.56 feet diameter, 6.5 feet high). For ...
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What is Gor'kov potential?

I'm studying acoustic levitation and have come across this term called "Gor'kov Potential" and did not know what it was. I did a Google search but all I found was research papers loosly ...
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Why is there a Nyquist limit in pulsed-wave doppler ultrasound?

The Nyquist limit represents the maximum Doppler shift frequency that can be correctly measured without resulting in aliasing, and always equals the Pulse Repetition Frequency (PRF)$/2$. However why ...
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Can I make an ultrasound machine using dust particles of different sizes sticking to paper with static electricity?

If I surrounded an object (to be scanned) with cylinders of paper - each sheet of paper with different sized dust particles sticking to it through static electricity, and then struck the test object ...
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Do humans use the doppler effect to localize sources of sound?

Consider a source of sound such as a person speaking or a party of people which makes a continual drone sound of the the same frequency. If a human shakes their head side-to-side with sufficient ...
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If the frequency of a sound wave doubles, does its energy quadruple?

Or does it double? What about its 'intensity' or power? Acoustic physics is confusing me more than electromagnetic waves did.... Is there a single list somewhere of the equation(s) relating to sound?
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Ultrasonic wave - connection wave speed to amplitude?

An ultrasonic wave is sent through a dispersive medium. That means the waves move at different frequencies with different phase velocities. If this were measured in the frequency spectrum, would the ...
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Metal - dispersive media?

Can metal alloys be regarded as "dispersive media" if they are excited with ultrasonic waves?
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Wave propagation transverse waves - dispersive or non-dispersive?

Is the propagation of shear waves (transverse waves) in solid media dispersive or non-dispersive? I'm thinking here of ultrasonic waves that propagate in quasi-isotropic material (metal).
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I need help with calculating the intensity of ultrasound

A distance meter, see the picture below, uses ultrasound with a frequency of 50 kHz. The ultrasound is generated by a circular piezoelectric transducer (flat surface that vibrates) with a diameter of ...
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6 answers
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How can ultrasound hurt human ears if it is above audible range?

Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. Then ultrasound is above 20 kHz Occupational exposure to ultrasound in excess of 120 dB may lead to hearing loss. Source How ...
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In ultrasound, why doesn't the reflected sound gets reflected again on its way back?

Consider the diagram below illustrating how A-scans work, why doesn't some of the reflected sound on its way back at the red circle interface reflect again (thereby reducing the signal intensity ...
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What frequency ranges are best for speakers? [closed]

I have two speakers, one is a 6-inch speaker and another one is Peavy PR 10 (Large speaker). What frequency ranges are best suited for each of the speakers and why?
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How does particle acceleration amplitude relate to particle resonant frequency? (ULTRASOUND)

In diagnostic ultrasound the acoustic pulse propagates in a non-linear fashion (Duck 2002). I have been taught that: The increase in wave velocity in the compressive phase increases particle ...
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3 answers
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Why are ultrasound devices using ultrasound? [closed]

I wonder why ultrasound devices are using ultrasound. Is it a biological reason due to our human audible range? Or is there a physical reason for that?
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Does the energy of a sound wave depend on frequency?

The energy of electromagnetic waves is said to be dependent on frequency. Is the energy of a sound wave also dependent on frequency?
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Ultrasonic vs x-ray (for medical applications)

What are the differences between using x-rays and ultrasounds for medical diagnosis? From a physical point of view I am aware that x-rays are able to reach deeper into the material - but I think this ...
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