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Ultrasonics - How Ultrasonic Waves Are Generated, Ultrasonic Dispersion, Ultrasonic Cleaning, Welding, Nondestructive Testing, Scientific Research - Applications, Coagulation, Humidification, Milk homogenization and pasteurization, Drilling, Soldering, El

sound khz ultrasound air

Ultrasonics or ultrasound, derived from the Latin words "ultra," meaning beyond, and "sonic," meaning sound, is a term used to describe sound waves that vibrate more rapidly than the human ear can detect.

Sound waves travel as concentric hollow spheres. The surfaces of the spheres are compressed air molecules, and the spaces between the spheres are expansions of the air molecules through which the sound waves travel. Sound waves are thus a series of compressions and expansions in the medium surrounding them. Although we are used to thinking of sound waves as traveling through air, they may also propagate through other media.

The technical name for one expansion and one compression is a cycle. Thus, a vibration rate of 50 cycles per second produces 50 expansions and 50 compressions each second. The term frequency designates the number of cycles per unit of time that a sound wave vibrates. One cycle per second is called a hertz and is abbreviated Hz. Other useful units of scale in ultrasonics are kilohertz (kHz), which represents 1,000 Hz; and megahertz (MHz), representing 1,000,000 Hz or 1,000 kHz.

Most people can only detect frequencies of sound that fall between 16 and 16,000 Hz. Ultrasonics has come to describe sound waves with frequencies greater than 16,000 Hz, or 16 kHz. Some insects can produce ultrasound with frequencies as high as 40 kHz. Small animals

TABLE 1. VELOCITY OF SOUND IN VARIOUS MEDIA
Material Velocity (ft/sec)
aAll measurements at 25°C (room temperature) unless otherwise indicated.
Sea water 5023
Distilled water 4908
Chloroform 3237
Dry air at 0°C 1086
Hydrogen at 0°C 4212
Brick 11,972
Clay rock 11,414
Cork 1640
Paraffin 4264
Tallow 1279
Polystyrene 3018
Fused silica 18,893
Aluminum 16,400
Gold 6658
Silver 8790
Concrete 12,000
Stainless steel 16,400



such as cats and dogs hear frequencies of up to 30 kHz; and bats are known to detect frequencies of up to 100 kHz.

A sound wave that causes compressions and expansions of the molecules in the medium surrounding it as it propagates is called a longitudinal wave. The distance from one compression to the next is known as the wavelength of the sound wave. Sound waves with long wavelengths pass over small objects in much the same way that ocean waves pass over small objects. Sound waves with short wavelengths, on the other hand, tend to be diffracted or scattered by objects comparable to them in size.

The propagation velocity of a sound wave is obtained by multiplying the frequency of the sound wave by its wavelength. Thus, if the wavelength and frequency of the sound wave in a given medium are known, its velocity can also be calculated. The sound velocities in a variety of materials are shown in Table 1.

As ultrasonic waves tend to have very high frequencies, it follows that they also have very short wavelengths. As a result, ultrasonic waves can be focused in narrow, straight beams.


The number of applications for ultrasound seems to be limited only by the human imagination. There are literally dozens of ways that people have already found to make use of ultrasound.


Ultrasound has been used to bind, or coagulate, solid or liquid particles that are present in dust, mist, or smoke into larger clumps. The technique is used in a process called ultrasonic scrubbing, by which particulate matter is coagulated in smokestacks before it pollutes the atmosphere. Coagulation has also been used at airports to disperse fog and mist.


In ultrasonic humidification, water is reduced to a fine spray by means of ultrasonic vibrations. The water droplets are propelled into a chamber where they are mixed with air, and a mist of air and water leaves the humidifier and enters the room to be humidified.


Ultrasonic waves can be used to break up fat globules in milk, so that the fat mixes with the milk (homogenization). In addition, pasteurization, the removal of harmful bacteria and microorganisms, is sometimes done ultrasonically.

By attaching an ultrasonic impact grinder to a magnetostrictive transducer and using an abrasive liquid, holes of practically any shape can be drilled in hard, brittle materials such as tungsten carbide or precious stones. The actual cutting or drilling is done by feeding an abrasive material, frequently silicon carbide or aluminum oxide, to the cutting area.


In ultrasonic soldering, high frequency vibrations are used to produce microscopic bubbles in molten solder. This process removes the metal oxides from the joint or surface to be soldered, and eliminates the need for flux.


Conversations can be overheard without using microphones by directing ultrasonic waves at the window of the room being monitored. Sounds in the room cause the window to vibrate; the speech vibrations produce characteristic changes in the ultrasonic waves that are reflected back into the monitor. A transducer can be used to convert the reflected vibrations to electrical signals that can be reconstructed as audible sounds.


Radio talk shows routinely use ultrasonic delay lines to monitor and cut off abusive callers before their comments are aired during radio talk shows. The ultrasonic delay line bounces the voice signal back and forth between two transducers until it has been monitored, then releases it for broadcast.

Resources

Books

Knight, David C. Silent Sound: The World of Ultrasonics. New York: Morrow, 1980.


Randall Frost

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cycle

—One wave expansion and compression.

Hertz

—A unit of measurement for frequency, abbreviated Hz. One hertz is one cycle per second.

Kilohertz (kHz)

—One thousand hertz.

Megahertz (MHz)

—One thousand kilohertz.

Piezoelectric

—A material that becomes electrically charged when compressed, generating an electric current.

Transducer

—An electronic device used to generate ultrasound.

Ultrasound

—Another term for ultrasonic waves; sometimes reserved for medical applications.

Wavelength

—The distance between two consecutive crests or troughs in a wave.

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about 4 years ago

Add more information, sir/madam. More information is required.

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over 3 years ago

The above information is sufficient for me to make understand about ultrasonic.

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almost 4 years ago

this imformatoin will help for making my project.

thanks for this website

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almost 6 years ago

I have ringing in my ears. My neighbor may have an electronic device in regards to dear hunting. I believe this device is causing the ringing in our ears, can you tell me how this would affect our health and also how to block his device to stop the ringing in our ears as it is making us ill.

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over 3 years ago

how to used the ultra sonic in transmitting&reciveing purpose

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over 3 years ago

Great information indeed......
Really created rather more scientific approach...
nice....

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about 3 years ago

Can you guide how ultrasonic or electromagnetism can be used for removing milk scales in pasteurization plant

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over 2 years ago

Ultrasonics - How Ultrasonic Waves Are Generated, Ultrasonic Dispersion, Ultrasonic Cleaning, Welding, Nondestructive Testing, Scientific Research - Applications, Coagulation, Humidification, Milk homogenization and pasteurization, Drilling, Soldering, El

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Ultrasonics or ultrasound, derived from the Latin words "ultra," meaning beyond, and "sonic," meaning sound, is a term used to describe sound waves that vibrate more rapidly than the human ear can detect.



Sound waves travel as concentric hollow spheres. The surfaces of the spheres are compressed air molecules, and the spaces between the spheres are expansions of the air molecules through which the sound waves travel. Sound waves are thus a series of compressions and expansions in the medium surrounding them. Although we are used to thinking of sound waves as traveling through air, they may also propagate through other media.



The technical name for one expansion and one compression is a cycle. Thus, a vibration rate of 50 cycles per second produces 50 expansions and 50 compressions each second. The term frequency designates the number of cycles per unit of time that a sound wave vibrates. One cycle per second is called a hertz and is abbreviated Hz. Other useful units of scale in ultrasonics are kilohertz (kHz), which represents 1,000 Hz; and megahertz (MHz), representing 1,000,000 Hz or 1,000 kHz.



Most people can only detect frequencies of sound that fall between 16 and 16,000 Hz. Ultrasonics has come to describe sound waves with frequencies greater than 16,000 Hz, or 16 kHz. Some insects can produce ultrasound with frequencies as high as 40 kHz. Small animals

TABLE 1. VELOCITY OF SOUND IN VARIOUS MEDIA Material Velocity (ft/sec)

aAll measurements at 25°C (room temperature) unless otherwise indicated.

Sea water 5023

Distilled water 4908

Chloroform 3237

Dry air at 0°C 1086

Hydrogen at 0°C 4212

Brick 11,972

Clay rock 11,414

Cork 1640

Paraffin 4264

Tallow 1279

Polystyrene 3018

Fused silica 18,893

Aluminum 16,400

Gold 6658

Silver 8790

Concrete 12,000

Stainless steel 16,400









such as cats and dogs hear frequencies of up to 30 kHz; and bats are known to detect frequencies of up to 100 kHz.



A sound wave that causes compressions and expansions of the molecules in the medium surrounding it as it propagates is called a longitudinal wave. The distance from one compression to the next is known as the wavelength of the sound wave. Sound waves with long wavelengths pass over small objects in much the same way that ocean waves pass over small objects. Sound waves with short wavelengths, on the other hand, tend to be diffracted or scattered by objects comparable to them in size.



The propagation velocity of a sound wave is obtained by multiplying the frequency of the sound wave by its wavelength. Thus, if the wavelength and frequency of the sound wave in a given medium are known, its velocity can also be calculated. The sound velocities in a variety of materials are shown in Table 1.



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As ultrasonic waves tend to have very high frequencies, it follows that they also have very short wavelengths. As a result, ultrasonic waves can be focused in narrow, straight beams.







The number of applications for ultrasound seems to be limited only by the human imagination. There are literally dozens of ways that people have already found to make use of ultrasound.







Ultrasound has been used to bind, or coagulate, solid or liquid particles that are present in dust, mist, or smoke into larger clumps. The technique is used in a process called ultrasonic scrubbing, by which particulate matter is coagulated in smokestacks before it pollutes the atmosphere. Coagulation has also been used at airports to disperse fog and mist.







In ultrasonic humidification, water is reduced to a fine spray by means of ultrasonic vibrations. The water droplets are propelled into a chamber where they are mixed with air, and a mist of air and water leaves the humidifier and enters the room to be humidified.







Ultrasonic waves can be used to break up fat globules in milk, so that the fat mixes with the milk (homogenization). In addition, pasteurization, the removal of harmful bacteria and microorganisms, is sometimes done ultrasonically.



By attaching an ultrasonic impact grinder to a magnetostrictive transducer and using an abrasive liquid, holes of practically any shape can be drilled in hard, brittle materials such as tungsten carbide or precious stones. The actual cutting or drilling is done by feeding an abrasive material, frequently silicon carbide or aluminum oxide, to the cutting area.







In ultrasonic soldering, high frequency vibrations are used to produce microscopic bubbles in molten solder. This process removes the metal oxides from the joint or surface to be soldered, and eliminates the need for flux.







Conversations can be overheard without using microphones by directing ultrasonic waves at the window of the room being monitored. Sounds in the room cause the window to vibrate; the speech vibrations produce characteristic changes in the ultrasonic waves that are reflected back into the monitor. A transducer can be used to convert the reflected vibrations to electrical signals that can be reconstructed as audible sounds.







Radio talk shows routinely use ultrasonic delay lines to monitor and cut off abusive callers before their comments are aired during radio talk shows. The ultrasonic delay line bounces the voice signal back and forth between two transducers until it has been monitored, then releases it for broadcast.



See also Acoustics; Solder and soldering iron.







Resources

Books

Knight, David C. Silent Sound: The World of Ultrasonics. New York: Morrow, 1980.







Randall Frost



KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



Cycle

—One wave expansion and compression.



Hertz

—A unit of measurement for frequency, abbreviated Hz. One hertz is one cycle per second.



Kilohertz (kHz)

—One thousand hertz.



Megahertz (MHz)

—One thousand kilohertz.



Piezoelectric

—A material that becomes electrically charged when compressed, generating an electric current.



Transducer

—An electronic device used to generate ultrasound.



Ultrasound

—Another term for ultrasonic waves; sometimes reserved for medical applications.



Wavelength

—The distance between two consecutive crests or troughs in a wave.



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Vibration MeasurementPortable vibration analyzer4~32 channel vibration analyzerwww.benstone.com

Tubular Corrosion ControlLeading inspection, machining,corrosion control, and inventory.www.nov.com

Ultrasonic HomogenizersSonifier - Ultrasonic HomogenizerSmall and Large Volume ProcessingUltrasonicHomogenizer.com

Additional Topics

Ultrasonics - How Ultrasonic Waves Are Generated

In order to duplicate ultrasonic frequencies, humans have harnessed the electrical properties of materials. When a specially cut piezoelectric quartz crystal is compressed, the crystal becomes electrically charged and an electric current is generated: the greater the pressure, the greater the electric current. If the crystal is suddenly stretched rather than being compressed, the direction of the …



Ultrasonics - Ultrasonic Dispersion

Ultrasonics - Ultrasonic Cleaning

Ultrasonics - Welding

Ultrasonics - Nondestructive Testing

Ultrasonics - Scientific Research

Ultrasonics - Medicine

Perhaps in no other field has there been such an explosion of ultrasound applications as in medicine. Ultrasound has been used in the following applications: …



Ultrasonics - Detection Devices

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over 2 years ago

How intresting infor mation .i really got happiness to read this information.i really love it. so, i want more information about this information. thanks so much for that.

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over 2 years ago

Hi,
Please forward all info re ultrasonic water treatment for toxic algae and bacteria.
Thanks

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over 3 years ago

can you send to me more information about ultrasonic for Wolf?