Report on ultrasound physics By Ayah Abd-Elnasser Mohammad zaky Biomedical Engineering Department Cairo University

1. ultrasonic
waves

2. Contents of the report
Introduction
Physicist Definition
Sound wave properties
Classification of sound wave
Examples of using ultra sound waves in the field of medicine
General about ultrasonic
Sources

3. Introduction :
The sound is a frequent, or wave able to move in several physical media such as
solids, liquids, and gases, and do not spread in a vacuum, and the organism can
palpation through a special member named ear. From the perspective of Biology
The noise is a signal containing the tone or several tones come from the
neighborhood who Lists emitting sound owns the object, used as a means of
communication between him and another object of the same sex or of another
race, through which what he wants to say or do consciously or without a prior
awareness , sensation caused by these vibrations hearing is called.
The estimated speed of sound in the middle of a normal antenna 343 meters
per second or 1224 kilometers per hour. Related to the speed of sound by a
factor of hardness and density of matter in which the sound moves.
Sound is a mechanical vibration of the center, but the sound is not the wave of
the wave is one of the formats (diffusion models) which highlights and is
characterized by the sound and an example of the other models: audio streams
audio streaming
There are other factors that affect the spread of the sound and speed such as the
nature of Article (viscosity, affected by magnetic fields)

4. .
Physicist definition
From the perspective of physics is the noise of the wave. And be a wave in liquids
and gases as well as a longitudinal wave is also in the air. In solids Sound Venture
in transverse waves. And the movement of waves middle molecules (usually air)
about an intermediate state and private spread quickly, and symbolizes the speed
of sound c. And the movement of waves Sound energy. Sound does not spread in
a vacuum.
The speed of sound depends on the medium in which transmitted. The speed of
sound in air 343 meters per second at a temperature of 20 ° C and 1407 m / s in
the water at zero percentile score.
Can calculate the acoustic wavelength lambda wave of frequency f and the
speed of sound c by the equation:
lambda = frac {c} {f}
Usually be differences in pressure or density in the cause of the change in speed.
This is evident when we imagine the sound pressure level is estimated at 130 dB
dB. This is a degree of hurt human ear, and represents its normal atmospheric
pressure: an atmospheric pressure of air static Pascal 101325, while the sound
pressure level of 130 dB his actual value of the sound pressure of 63 Pa p only.

5. Acoustic or sound waves directed at the center of any movement of seis.mic
movement of seismic fast particles of molecules that make up the center
composed. The movement of one of the middle molecules lead to the disruption
of neighboring molecules, which in turn do the same work, and so forth, so that a
wave of unrest reflects the middle of the first movement starting point. When the
vibrating tuning fork in the air, the Division shaky movement to press forward air
next door. However, it quickly this region back pressurized air to its normal
thanks to the special rubber-conditioning and compression neighboring regions
account, so that prompt from excess pressure spreads starting from shaky
Division of tuning fork, the same way the shaky Division movement back
generate prompt pressure incomplete or dislocations.
Tuning fork generated in this way is what we call net Pure Tune sound, which is
expressed in a quantitative two elements are the frequency of vibration Frequency
and Amplitude capacity or intensity
Sound waves properties

7. The height of the tuning fork - and thus any molecule from the middle adjacent
molecules suffer simple harmonious movement in the main direction of wave
propagation so that they can represent the positions this molecule in the movement for
the time sine wave. If the movement of the vibration source simple movement is not
consistent forward and backward, the waveform to be complicated, and this is the recipe
more natural acoustic stimuli. This can be mathematically complex wave analysis to two
waves or more of the sinusoidal waves that can then be identified former program
elements, i.e. frequency and intensity.
The intensity of the sound wave:
Is the amount of energy that affect one square centimeter of the center during the
passage of the sound wave, as the unit decibels is the one used to express the amount of
directed energy. Given the changing acoustic intensities significantly, which picked up the
ear and excellence, these wrenches are expressed in terms of Gareetmah real values.
When we say that the intensity of the sound as well as what are the decibels, this means
that this figure is ten times the logarithm of the ratio of the sound energy into other
energy agreed.
Sound waves properties (cont.)

8. Sound waves properties (cont.)
Energy = (pressure) 2
DB = 10 X (pressure) 2
DB = 10 X Energy
An example: The difference between the less severe and stronger intensity
borne human ear is 120 decibels. This quantity is the ratio of the strong voice
of thunder energy to sound energy in the minimum threshold of hearing, and
one decibels represents a real increase in the audio equivalent to the capacity
of 1, 26 times.
As the decibels ratios measure, it must adopt a standard or document for
comparison with the ratio him. For example, it can rely on the minimum
threshold of hearing, but this standard varies from one person to another and
very different depending on the frequencies of the sound.
Therefore, and in order to avoid these considerations involved in this matter
agreed to adopt the standard convention is Almikrooat. Since the watt is a
measure of the rate of flow of energy per square centimeter Valmkrooat
nearly minimum threshold of hearing Do not allow to hear the voice
frequency (1000) pulse per second.

9. Classification of sound waves
Sound waves are classified according to their frequencies are as follows:
Radio waves
Waves are those that fall frequencies between 20 Hz and 20,000 Hz, and
represents the voice by the normal human ear. Where the minimum
frequency sound that improve the natural human ear is about 20 hertz,
while the upper limit is 20 000 Hz, and this term decline in the elderly to
about 12,000 Hz. The maximum sense of sound to a human ear is located
in the normal range between 5000 Hz and 8000 Hz, which includes the
vibrations of the alphabet. As is known, can be audio-band events through
the vocal cords in the human and musical instruments stringed whether or
copper or tube and other machines.

10. Waves benchtop audio
Classification of sound waves
Are waves that increase frequencies on 20 000 Hertz, which lies outside the
scope of the sense of the human ear. This type of wave is still the subject
of intense research and attention given the task of applications that affect
many areas in industry, medicine and others. It has become possible to
produce ultrasonic waves at frequencies exceeding 1000000 Hertz and not
different from these waves where the properties of the sound waves from
the other, but that due to the short length of the waves it is possible to
move the minute high-energy X-ray body.
(cont.)

11. Examples
of using
ultra sound
waves in the
field of
medicine

12. Waves without audio
Sound waves are less frequency than 20 Hz and the human ear can
not sense the most important and it is a source of seismic and sliding
movement of the layers of the earth's crust and the resulting
earthquakes and volcanoes and therefore it is very important to
monitor earthquakes and volcanic activity tracking. Some animals can
sense earthquakes before they happen.
The speed of sound varies according to the center in which the sound
waves spread and type temperature shall be higher in solids and
liquids in less and much less in gas. For the spread of sound in the air
depends on the pressure, that is less than the speed of sound to rise
above the ground.
Classification of sound waves (cont.)

13. General about ultrasonic
The speed of sound waves in fluids is given by equation
v = sqrt { frac {E} {d}}
The speed of sound in air at zero percentile score is 331.1 m / s, and
increases the speed rising temperature. Estimated the speed of sound
in water B1450 m / s at standard grade (15 ° C). These range in speed
solids between 3000 and 6000 m / s, for example, it is 5100 m / s for
iron, aluminum and 3560 m / s for copper and reach 5200 meters per
second in the glass.

14. The intensity and loudness
Shaky published acoustic wave sends energy with this wave, and
you know the sound intensity in terms of energy carried by this
wave, and in order to investigate precision draw an area of the
unit perpendicular to the direction of propagation, and then you
will know the wave intensity as the energy carried by the wave in
the second cross-unit vertical spaces direction of wave
propagation, and where that is the energy intensity in the
second, then the intensity of the sound is the ability passers-through
unit area perpendicular to the direction of wave
propagation, and units of sound intensity is watts per square
meter.
General about ultrasonic (cont.)

15. The table illustrates the severity of some of the
votes, he noted that the extent of the volume,
which can authorize to hear a very broad.
Sound intensity w m2 dB
sound level intensity
Sound Type
Sound that causes pain 120 1
Punch rock Pneumatic 100 2−10
Heavy road traffic 70 5−10
Normal conversational 60 6−10
Average height whisper 20 10−10
The rustle of the trees 20 10−10
Voice barely 0 12−10

16. Express permission of the sounds way better response is
commonly used measure of sound intensity, or dB scale, based on
the forces of the number 10.
It can be noted in DB scale that the minimum intensity of voice
barely medium permission any (10 ^ {- 12} W / m ^ 2) is zero in
decibel scale, the greater the intensity of sound 10 times higher
intensity of sound level in decibels by 10 units, It has been found
that the permission to control the votes according to the decibel
scale.
General about ultrasonic (cont.)

17. Wikipedia and Google ..

18. Dr. Mohamed Hesham

19. By: Ayah Abd-Elnasser
Mohammad Zaky …
First Division of Biomedical
Engineering Department - Cairo
University..
Sec:1
BN.15

20. Thank You