What is Ultrasound: Definition and 111 Discussions

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz (20,000 hertz) in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.
Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles.

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  1. R

    Ultrasound NDT (non-destructive testing)

    Hi all, I've a question and I hope that I can get some answers here. As what my project has tasked, and what my lecturer had said. He needs me to build a device for NDT Testing. Currently the set up is that I would source for a transducer via olympus coupled with a USB oscilloscope capable...
  2. X

    FDTD of (ultrasound) wave propagation through muscle

    Im a mechanical engineering student currently, with a third year project of simulating ultrasound propagation through the abdomen. Currently i just want to simulate it going through muscle with no obstacles. I don't really understand where to start, I have formed some equations based on the wave...
  3. M

    What type of equipment is required to detect ultrasound above 1MHz?

    Please list any links in you have them.
  4. A

    How does ultrasound imaging work?

    From what I understand, ultrasound beams are generated from hundreds of piezo crystals that constructively interfere with one another. When the beam is reflected, it returns to the crystals and the crystal directly above the reflection (the crystal that obtains mechanical vibrations) records the...
  5. W

    Coupling Gel in Ultrasound Imaging - Density?

    Dear all, I have a quick question about the use of coupling gel in ultrasound imaging (of an unborn child as an example). As I understand it, if coupling gel were not used, as the ultrasound waves left the transducer, they would undergo a massive amount of reflection at the air-skin (body...
  6. F

    A liquid matter from a solid matter with a help of ultrasound?

    Good morning, I would like to ask you... Is it possible to make a liquid matter from a solid matter with a help of ultrasound? At first, what happens if the ultrasound travels through a solid matter (for example quartz)? What happens to a solid matter during a positive amplitude (compression)...
  7. strangerep

    Ultrasound discrimination capabilities?

    Hi all, First time poster in this forum. (I usually hang out over in the quantum physics forum). I'm hoping there's someone here who knows technical details of ultrasound imaging and associated diagnostic techniques. More specifically, how good/bad is ultrasound imaging for...
  8. M

    Ultrasound - intensity reflection coefficiant calculations

    Homework Statement The following table gives some specific acoustic impedances Tissue or Medium Specific acoustic impedance Air 0.00044 x 10^6 Fat 1.38 x 10^6 Water 1.5 x 10^6 Brain 1.58 x 10^6 Blood 1.59...
  9. B

    Sound speed = ultrasound speed?

    Hi, I'm doing a lab report and I need to know if ultrasound speed in the air is the same of sound speed in the air. Thank you
  10. G

    Ultrasound velocities in h20/propylene glycol mixtures

    I started with a 100% water sample, and measured the speed of ultrasound using 1MHz transducer, and in 10% increments added propylene glycol to the sample fixture until I reached 100% propylene glycol. Curiously, the velocity of ultrasound waves when plotted against % propylene glycol...
  11. S

    Ultrasound intensity in fat, muscle and bone

    Homework Statement The specific impedance of fat, muscle and bone are 1.4 x 106 kg m-2 s-1 , 1.6 x 106 kg m-2 s-1 and 6.5 x 106 kg m-2 s-1 respectively. The linear absorption coefficients in fat and in muscle are 0.24 cm-1 and 0.23 cm-1 respectively. A parallel beam of ultrasound of...
  12. S

    Ultrasound from compact florescent light bulbs

    Are compact florescent light bulbs know to be strong sources of ultrasounic noise? I've been playing with a "Marksman Ultrasonic Diagnostic Tool", which presents ultrasounds as audible sound. It isn't a scientific instrument, so it doesn't give a decibel reading. It is used to detect leaks...
  13. M

    If ultrasound can be used to measure elasticity

    can you simply extract the elasticity from ultrasound medical images? I don't know ultrasound very much but I just found out it can measure elasticity. under what condition can ultrasound be used to measure elasticity of some deformable object and do ultrasound medical images qualified for...
  14. L

    Energy associated with ultrasound cleaning

    Hi everybody, I am using a ultrasonic water bath cleaner in one of my experiments. It is basically a container filled with water. Items which need cleaning are immersed and, when the machine starts, a transducer emits waves at a frequency of 35 kHz. The ultrasounds produce water cavitation...
  15. C

    Build an Ultrasound Device for Plant Growth

    hi all, i am looking to build an ultrasound producing device that emits at 50,000 cps? i need a list of materials and how to construct the circuit. research shows that you can multiply the growth of plants (radishes were tested) by 150% if subjected to ultrsound at around 50,000 cps. thank you...
  16. D

    Can a Simple AD Converter Be Built for Ultrasound Analysis?

    I was building a simple bat detector for a child and also built one for me: http://home.earthlink.net/~bat-detector/SBD2Parts.html Now I was wondering whether it would be possible to built a simple AD converter, which can be fed the amplified signal of the microphone before it enters the...
  17. N

    Why does ultrasound cause pain?

    hi, at this site: http://www.amazing1.com/ultra.htm they have a device called a "phasor pain field generator" does it really cause pain and nausea etc? why does it cause any long term effects? why is there no scientific proof about this anywhere? lol jk thanks...
  18. J

    Trying to find substitution material for Ultrasound gel

    Hi, I am developing a Ultrasound application where the sensor will be in contact with the skin but I can't use gel for accoustic coupling (or any liquid). Any ideas of materials (suppliers) for this purpose ? Thanks/Brgds Joao
  19. R

    Powerline Internet: Bypassing High Inductance tranformers using ultrasound

    Hi everyone. I was wondering about something I just read with wireless energy transfer and resonant energy transfer on Wikipedia.org. What if you send a large amount of ultrasound tuned to a certain frequency over the AC/DC outlet plug. Would it get to the Transformer? Would the transformer's...
  20. E

    Medical B-mode Ultrasound Image - what does it represent?

    Dear All, In medical imaging, the pixel intensity of a MR image may represent T1 relaxation time, T2 relaxation time, or proton density. These are intrinsic properties of tissues. For a B-mode ultrasound image, what does the pixel intensity represent? Do they represent the magnitude of...
  21. E

    Mesh generation from an ultrasound image

    Does anyone have a clue on how to obtain the mesh from the ultrasound image? The region of scatterer is automatically more densely meshed than its ambient. Any software? algorithm? Thx. Elgen
  22. G

    Determing frequency shift of an ultrasound

    Homework Statement A Doppler blood flow unit emits ultrasound at 5.0 MHz. What is the frequency shift of the ultrasound reflected from blood moving in an artery at a speed of 0.20 m/s? Express your answer using two significant figures. Homework Equations f' = f0(v/v-Vs) frequency shift = f'...
  23. M

    How Does an Ultrasound Machine Detect Reflected Waves?

    how does ultrasound machine detects the reflected wave? i have read a bit of information and unfortunately I am still unsure how they detect the wave. "The rapid shape changes, or vibrations, of the crystals produce sound waves that travel outward. Conversely, when sound or pressure waves...
  24. C

    Exploring the Directional Properties of Ultrasound Waves at 25 kHz

    Hey, i never quite knew where to post this so hope its okay here. can sound waves specifically ultrasound around the 25 kHz mark be directed sort of how a laser pen directs light. thanks.
  25. S

    Is a Top View Possible with Ultrasound Imaging? Understanding the Misconceptions

    Homework Statement I'm having trouble understanding exactly how the image goes from a transducer to the screen... When they put the transducer on the top of your stomach say, does this give a cross section view, from the side of your body rather than a top view as you would expect? Because...
  26. T

    Ultrasound and Chemical Repair of DNA: Is There Scientific Evidence?

    Is there any SCIENTIFIC evidence of the effect of ultrasound on chemical repair of DNA? As in, is there peer-reviewed research in this? Thanks.
  27. M

    Creating 23KHz Ultrasound: Components and Considerations

    Thanks for reading my post. I would like to produce 23KHz ultrasound at a presure of 70 to 100 dB. I am thinking that I will need a device to create the 23KHz signal, an amplifier, and either a transducer or a piezo-buzzer. I'm looking for a point in the right direction. Are there...
  28. W

    What Is the Wavelength of Ultrasound in the Human Body?

    1. Ultrasound with a frequency of 4.25MHz can be used to produce images of the human body. If the speed of sound in the body is the same as in salt water 1.50km/s, what is the wavelength in the body? 2. v= wavelength(f) M = 10^6 3. v= wavelength(f) wavelength =...
  29. M

    Finding upper and lower bound superposition frequencies of ultrasound pulses

    Homework Statement Ultrasound pulses of with a frequency of 1.000 MHz are transmitted into water, where the speed of sound is 1500m/s . The spatial length of each pulse is 12 mm. a) How many complete cycles are in each pulse? b) What is the lower bound of the range of frequencies must be...
  30. A

    Artificially aging wine via ultrasound

    http://www.dailymail.co.uk/sciencetech/article-1065867/The-miracle-machine-turns-cheap-plonk-vintage-wine--just-half-hour.html" I don't know enough about how wine ages to debate the above, but the following set the alarm bells off in my head: Mmm-hmm...
  31. D

    Medical X-ray, CT scan, Ultrasound, MRI detecting blanks ?

    This is for a sci-fi novel I’m writing, and I actually posted this at another site but the answers given were a little vague. What would occur, either on a computer monitor (or other monitoring device, depending on the machine) or on a photo film, if an: a. X-ray b. CT scan c. ultrasound...
  32. Q_Goest

    Medical Discover the G Spot: Ultrasound Scans Uncover Its Location

    Seems the illusive "G spot" has been identified. Take a look for it here! http://www.newscientist.com/article/mg20026872.500-ecstasy-over-g-spot-therapy.html It's a thick layer of tissue on the front vaginal wall which has been identified using ultrasound. And if you actually want to...
  33. E

    Calculating Speed of Ultrasound in Soft Tissue

    i have a problem: ultrasound takes 70μs to go 100mm in soft tissue/ show that its speed is about 1400ms -1 well i don't really know what fomulas to use but i would say putting 70μs x 10 power -6 so that is 0.000007 then I am stuck... thanks in advance ;D
  34. B

    Doppler shifted frequency - ultrasound

    Homework Statement An object is moving at speed vo toward a source at rest that is emitting sounds waves with frequency fo. What is the doppler shifted frequency of the reflected wave that comes back to the source? Homework Equations The Attempt at a Solution If I use the...
  35. A

    What is the Doppler shift equation for a stationary source and moving observer?

    Homework Statement The calibration for a piece of ultrasound equipment states that the velocity of blood flow in the aorta is normally about 0.28 m/s, and that the detector emits a frequency of 4.20 MHz. a) If the ultrasound waves were directed along the blood flow and reflected from the...
  36. B

    What is the diameter of the baby's head based on ultrasound echoes?

    Homework Statement Ultrasound waves are used to find the size of an unborn baby's head. Echoes are received from the front and the back of the skull bone. The reflected sound pulses are detected and displayed on an oscilloscope screen that shows that the echoes are 0.15ms apart. If the speed...
  37. A

    Calculating Ultrasound Speed in Liquid Using an Oscilloscope Trace

    Homework Statement A food packaging factory is moving soup through a 0.075 m diameter pipe when an obstruction occurs in the pipe. An ultrasound probe, connected to an oscilloscope, is moved along the pipe to find the obstruction (Figure 1). The oscilloscope trace is shown below (Figure 2)...
  38. M

    Cleaning Bottles with Ultrasound

    A mate of mine who has a hobby involving digging up old bottles (and other items) from old rubbish dumps, came across instructions for cleaning the bottles with ultrasound. The instructions he showed me involved using a metal tank, signal generator set to 40kHz and a 'transducer'. I...
  39. M

    Investigating the Effects of Pregnancy Gel on Ultrasound Reflection

    (Not Spam :-p) I did a bit of reading today on partial reflection when using ultrasound. I was reading about a pregnancy gel that is applied to the womans stomach when detecting a baby. To put it briefly, if the ultrasound transmitter is held away from the body a lot of energy is reflected...
  40. C

    Ultrasound transmitter component- longitudinal or transverse waves?

    Pretty basic question, i think, it's either possible or it's not. Physics practical using an ultrasound generator and receiver components (in separate circuits, with the the generator rigged up to signal generator, and the receiver connected to an oscilloscope to take readings from). For the...
  41. M

    Doppler effect and Ultrasound waves

    Homework Statement Ultrasound waves are used to measure blood-flow speeds. Suppose a device emits sound at 450 kHz, and the speed of sound in human tissue is taken to be 1540 m/s. What is the expected beat frequency if blood is flowing normally in large leg arteries at 3.0 cm/s directly away...
  42. A

    Calculating the speed of an ultrasound wave in an unknown liquid

    Homework Statement An ultrasound unit sends a 2.40 MHz sound wave into a 25.0-cm-long tube filled with an unknown liquid. A small microphone right next to the ultrasonic generator detects both the transmitted wave and the sound wave that has reflected off the far end of the tube. The two sound...
  43. R

    Different methods to produce ultrasound and its applications

    Hi, I'd like to know all about different methods to produce ultrasound and its applications. Can somebody give me detailed description of the methods of production of ultrasound? Or at least give me the links for such descriptions? Regards. -- rAgAv
  44. R

    How can we produce ultrasound?

    Hey everybody, I have some simple questions on ultrasound and its production... How can we produce ultrasound? (or rather "where can I get detailed information on the methods of producing ultrasound?") What are the general properties of ultrasound? Regards. -- rAgAv
  45. J

    How does contrast resolution work in ultrasound?

  46. J

    Pulse vs Continuous transducers (Ultrasound)

    I am a student in a DMS program. Our instructor poised the following question (worth extra credit!) if we can answer it and back it up. OPERATING FREQUENCY IN PULSED WAVE TRANSDUCERS IS DETERMINED BY: A. FREQUENCY OF THE VOLTAGE B. PULSE REPITITION FREQUENCY C. THE MEDIUM ONLY D. THE THICKNESS...
  47. A

    Drive a piezo crystal to produce ultrasound?

    Hi, Could I use the following item: http://docs-europe.electrocomponents.com/webdocs/03c4/0900766b803c41c7.pdf" to drive a piezo crystal to produce ultrasound? I know it wouldn't be perfect but it might be good enough for a small underwater depth sensor. Any ideas if it's possible?
  48. C

    Calculating Beat Frequency in Ultrasound Reflection from Moving Bloodstream

    Homework Statement Ultrasound reflected from an oncoming bloodstream that is moving at 38 cm/s is mixed with the original frequency of 1.3 MHz to produce beats. What is the beat frequency? (Velocity of sound in blood = 1540 m/s.) Homework Equations Fo=Fs(v+Vo/v) Fb- (F2-f1) The...
  49. F

    Ultrasound Physics: Beam Uniformity Coefficient

    Pertaining to ultrasound physics, what is a "Beam Uniformity Coefficient"? How is it calculated? And why is it important? etc... I need to write couple page paper on it and I can't seem to find any information about it anywhere...Thanks.
  50. F

    Ultrasound Physics: What is the Beam Uniformity Coefficient?

    Pertaining to ultrasound physics, what is a "Beam Uniformity Coefficient"? How is it calculated? And why is it important? etc... I need to write couple page paper on it and I can't seem to find any information about it anywhere...Thanks.
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