by Dr.Kadim Karim Mohsen Ali Thi-Qar University College of Engineering) 2012

2. by Dr.Kadim Karim Mohsen Ali Thi-Qar University College of Engineering) 2012 Analysis of Penetration of Noise Waves to the Human Body

3. الضوضاء • قال تعالى: (وعباد الرحمن الذين يمشون على الأرض هوناً . وإذا خاطبهم الجاهلون قالوا سلاماً)-الفرقان63 • قال تعالى: (واقصد في مشيك واغضض من صوتك) - لقمان19 • وعندما أراد رسول الله (ص) اختيار طريقة لتبليغ الناس دخول وقت الصلاة استشار أصحابه في ذلك ورفض اقتراحات بعضهم باستعمال الناقوس أو الطبول أو الأجراس، واختار الأذان بصوت الإنسان لأنه أدعى إلى الهدوء والسكينة والبعد عن الصخب، واختار بلالاً لأدائه لأنه أندى صوتاً • وإذا كان الإسلام ينهى عن إحداث الضوضاء في عباداته، فما بالك بهؤلاء الذين يحدثون الضجة بغير هدف سوى التلذذ والتمتع بإيذاء الناس بصراخهم أو إطلاق زمور سياراتهم، أو رفع مكبرات الصوت لمذياعهم أو آلات التسجيل وسواها وإزعاج جيرانهم وإجبارهم على سماع ما لا يريدون، كل هذا تعدٍّ على الحرية الشخصية التي احترمها الإسلام وأقرتها الشرائع الدولية . • ثم ألا يعلم هؤلاء الذين يحدثون الضجيج، كم من مريض في البيوت يحتاج إلى الراحة والنوم، أو شيخ مسن مضطرب في نومه، أو من طالب علم يحتاج إلى الدراسة والمذاكرة.

4. Objective of the Work Noise is any undesirable sound. Noise can increase stress. Very loud noise can damage your hearing, or even make you completely deaf.

5. What is Sound and what is Noise? • The word noise is derived from the Latin word NAUSES which means "seasickness" the unpleasant sounds made by seasick passengers or sailors • Britannica encyclopedia defines  Noise as  Unwanted sound  and U.S. Encyclopedia as Undesirable sound • From the legal view point may be defined as wrong pollution  is from the air, causing a material wounding of the right of individuals • Noise is a form of energy which is emitted by a vibrating body and transmitted by pressure fluctuation which the human ear can detect and on reaching the ear causes the sensation of hearing through nerves. • When one is speaking, the vibrating of vocal chords set air particles into vibration and generate pressure waves in the air, the person nearby may then hear the sound of the speech when the pressure waves are perceived by the ear.

6. Sound can also travel through other acoustic media, such as water or steel orGases • Sounds produced by all vibrating bodies are not audible. The frequency limits of audibility are from 20 Hz to 20,000 Hz. • <20Hz 20Hz to 20000Hz> 20,000Hz • Infrasonic - inaudible sonic-Audible Ultrasonic - inaudible

7. 0 20 Hz 20 kHz 5 MHz Human hearing and Frequency

8. Animals that can hear altrarasonicsound • Fish • Dogs • Whales • Snakes • application seismographs use for monitoring earthquakes • Animals that can hear infrasonic sound • Bats • Elephants • application • Sonar • Ultrasonic welding • Ultrasonic disintegration bacteria

9. Noise health effects

10. Noise health effects consequences exposure to elevated sound levels. • Temporary and sometimes permanent hearing loss • Presbycusis • Hypertension • Heart disease • Tinnitus • Annoyance and sleep disturbance • Changes in the immune system  • Birth defects , exposure of the pregnant woman in trouble and become unstable neurological condition which affects the fetus • Ischemic • Vasoconstriction and other cardiovascular impacts •  Impairment

11. Stress, increase workplace accident rates, and stimulate aggression and other anti-social behaviors. • Human life decrease from 8 to 10 years • Mental Autism • Excess secretion of certain glands cause high blood sugar • The headaches and fatigue and insomnia • Stomach ulcers • Blood pressure in school children in the vicinity of the airport is higher than the school children away with him, and their speed in solving mathematical problems less, and at their failure to resolve the matter quickly throw aside what they are not trying to re-solve. • Speech interference: if children who are learning to read cannot understand their teacher • Mental collapse

12. The power of jet noise

13. The power of jet noise A new study was published present a link, between jet noise and mental illness. The study find that the rate of mental illness hospital admission was 20 percent higher in Inglewood , where the los Angeles International Airport is located , than in El Segundo , about five miles away. The researchers chose El Segundo for comparison because census data showed its residents to be very much like those of Inglewood in age, race and Socio-economic background. The main difference was the jet noise level: above 90 decibels in Inglewood, 60 to 65 decibels in El Segundo. A study by British psychiatrists produced similar results .Mental hospital admission were 31 percent higher among people living close to London’s Heathrow Airport than among those who lived farther away.

14. General statistics 1- Hearing loss is the number one of disability of the world 2- hearing loss is the most preventable disability in the world 3- the number of people who need hearing aid 25 million 4- 15 every 1000 people under 18 yrs have hearing loss 5- 3 out of 100 school children are affected by hearing loss 6- percentage of people loss their hearing before age of 3 is 5.4 % 7- percentage of people who loss their hearing between 3 to18 yrs. is 14.2% 8- percentage of people who loss their hearing at age of 19 yrs. is 76.3 %

15. Sources of Noise Vehicles, trains, aircraft Radio and television Children playing Household gadgets Road traffic Transportation systems Construction work - construction of buildings, highways, and streets cause a lot of noise, due to the usage of air compressors, bulldozers, loaders, dump trucks, and pavement breakers. Industrial noise Boilers, generators, air conditioners, fans, plumbing and vacuum cleaners Prolonged exposure to loud music

16. Sound can be produced by many other sources - man's vocal cord, a running engine, a vibrating loudspeaker diaphragm, an operating machine tool, and so on.

17. Unpleasant, unwanted, disturbing sound is generally treated as Noise

18. The nature of noise • Noise , phenomena of vibration, travels in wave patterns through solids, liquids and gases. • The waves, caused by vibration of the molecules, follow sine functions, characterized by the amplitude and wavelength (or frequency) • Noise waves of equal amplitude with increasing frequency from top to bottom

19. When the medium is the air and pressure fluctuations falls on the air the hearing is produced • Sound is form of energy and is transmitted by collisions of air molecules one against the next and so on. • It may represented as a series of compressions and refractions in the density of air molecules which travel away from source

21. Sound is a disturbance that propagates through a medium having properties of inertia ( mass ) and elasticity. The medium by which the audible waves are transmitted is air. • Basically sound propagation is simply the molecular transfer of motional energy. Hence it cannot pass through vacuum. Frequency: Number of pressure cycles / time also called pitch of sound (in Hz) Guess how much is particle displacement?? 8e-3nm to 0.1mm

22. The disturbance gradually diminishes as it travels outwards since the initial amount of energy is gradually spreading over a wider area. If the disturbance is limited to one dimension ( tube / thin rod), it does not diminish as it travels ( except loses at the walls of the tube )

23. Classification of noise #according to duration #according tofrequency Continuous noise Spinning & weaving industry High frequency Saw sound Interrupted noise Grinders sound Traffic noise Law frequency Impulse&impact noise White noise Boiler sound explosions

24. White noise Combines the noise pulse and random noise and has a spectral bandwidth over a flat area of influence White Noise is a set of noise or sounds that brings together all the frequencies that humans can hear, which is located in the area of the frequency spectrum between 20 to 20000 Hz

25. Noise problem Consists of three inter-related elements source receiver transmission path. Transmission path is usually the atmosphere through which the sound is propagated, but can include the structural materials of any building containing the receiver

27. Characteristics of noise and the Decibel Scale

28. Characteristics C/CS of noise and the Decibel Scale • 1- Frequency of noise • Is the number of pressure fluctuation per second • Measured in (Hz) • The higher the frequency, the more high-pitched • The sounds produced by drums have much lower frequencies than those produced by a whistle

30. 2- Loudness • A loud noise usually has a larger fluctuation and a weak one has smaller pressure fluctuation. • Loudness of a sound is depends on the amplitude of the fluctuations above and below atmospheric pressure and frequency • Are expressed in Pascal (Pa) • Amplitude is the magnitude of pressure fluctuations compared with atmospheric pressure (1000 millibars =1bar= 105 N/m2 (Pa))

31. Range of Pressure Threshold of Hearing (20x10-6 Pa=20µPa) Threshold of pain(sensation of pain) (2000 Pa = 2x109 µPa) 1000000 times larger

32. To express noise in terms of Pa is quite inconvenient because we have to deal with numbers from as small as 20 to as big as 2,000,000,000.

33. LOUDNESS INDEX Loudness Level (Phon) useful for comparing two different frequencies for equal loudness The phon is a unit of loudness level for pure tones  1 phon is equal to 1 dB of SPL at a frequency of 1 kHz 0Phon: threshold of hearing Sone A unit of perceived loudness equal to the loudness of a 1000-Hz tone at 40 dB above threshold Direct relationship between Loudness Level ‘P’ (Phons) and Loudness Index ‘S’ (Sones) 8 Sones is twice as loud as 4 Sones

34. h = g + f j h k l s a k d g f q ew mcm .zxc /.,m bnx hsaj ppqw [[we I ooosa p'qwd owqdjwq poqwdj m h = g + f j h k l s a k d g f q ew mcm .zxc /.,m bnx hsaj ppqw [[we I ooosa p'qwd owqdjwq poqwdj m q l Sound pressure level Bels and decibels

35. Quantifying Sound Root Mean Square Value (RMS) of Sound Pressure • The ‘rms’ pressure is the square root of this time-averaged value. • In calculation of the ‘rms’, the values of sound pressure are squared to make them all positive and time-averaged to smooth out fluctuation.

36. Sound Power level Sound Intensity : Average rate of energy transfer per unit area Speed of Light: 299,792,458 m/s Speed of sound 344 m/s For air, 0c  415Ns/m3 so that Sound Power Level: dB Reference Power Wref=10-12 Watt (0dB) A sound in free space radiating sound uniformly in all directions as a sphere of radius r SPL=SWL-10 log 4πr2

37. Peak Power output: Female Voice – 0.002W, Male Voice – 0.004W, A Soft whisper – 10-9W, An average shout – 0.001W Large Orchestra – 10-70W, Large Jet at Takeoff – 100,000W 15,000,000 speakers speaking simultaneously generate 1HP

39. SOUND BITS • Unless there is a 3 dB difference in SPL, human beings can not distinguish the difference in the sound • Sound is perceived as doubled in its loudness when there is 10dB difference in the SPL.

40. Typical suburban sound and their levels

42. Levels in decibels calculation • It is practical measure of the amplitude of pressure fluctuations. • The human ear responds to a very wide range of intensities from the threshold of hearing TOH 20 µPa at 0 dB to the threshold of pain –feeling (loudest sound) TOP 20 X106 µPa is 120 dB.

44. COMBINATION OF SEVERAL SOURCES Total Intensity produced by several sources IT=I1+ I2+ I3+… Usually, intensity levels are known (L1, L2,…)

45. Sound Intensity

46. Addition of sound or Noises (decibels) levels Combination of sounds

47. Addition of sound or Noises (decibels) levels Combination of sounds adding 60 decibels to 60 decibels gives 63 decibels. The following formula explains the general principle of adding sounds on the decibel scale. One can use the above formula to add three sounds together - 60 dB, 65 dB and 70 dB.

50. Addition of sound levels can also be done simply using the following chart.