Architectural acoustics, New engineering materials ,ultrasoni

1. PHYSICS PRESENTATION
PRESENTED BY:-
1. 140410116054 PATEL HARSH
2. 140410116055 PATEL HETUL
3. 140410116056 PATEL JAINA
4. 140410116057 PATEL KINJAL
5. 140410116058 PATEL KUNJ

2. TOPICS FOR PRESENTATIOM
Architectural Acoustics
New Engineering Materials
Ultrasonic's

3. ARCHITECTURAL ACOUSTIC

4. CONTENT :
 INTRODUCTION
 CLASSIFICATION OF SOUND
 CHARACTERISTICS OF SOUND
 INTENSITY
 SOUND ABSORBING MATERIAL
 REVERBERATION TIME
 FACTORS AFFECTING ACOUSTICS OF BUILDING
 REMEDIES OF AFECTING FACTORS

5. INTRODUCTION :
 DEFINITION OF ACOUSTIC :-
ACOUSTICS is the SCIENCE of SOUND which deals with
the properties of SOUND WAVE , their origin, propagation
& their action on obstacles.
 ARCHITECTURAL ACOUSTICS deals with the design &
construction of music halls & sound recording rooms to
provide best audible sound to the audience.

6. CASSIFICATION OF SOUND :
 On the basis of frequency sound waves are classified
into 3 types.
- INFRA SOUND [f<20Hz]
- AUDIBLE SOUND [ 20Hz < f < 20kHz]
- ULTRA SOUND [ f > 20kHz]
 CLASSIFICATION OF AUDIBLE SOUND:
1) MUSICAL SOUND
2) NOISE

7. CHARACTERSTICS OF SOUND :
 PITCH : Related to Frequency of SOUND.
: The PITCH of SOUND changes due to
DOPPLER’s principle.
 LOUDNESS : Related to Intensity of SOUND.
: Relation between LOUDNESS(L) &
INTENSITY(I),
where K is constant.
 TIMBER : Related to Quality of SOUND.
L = K log I
L ∝ log10 𝐼

8. INTENSITY (I) :
 Definition:-Intensity is defined as the amount of
sound energy Q flowing per unit area in unit time.
 Mathematically Intensity is define as
 Unit:- Weber/m².
I = Q/At

9. LOUDNESS INTENSITY
 It is degree of
SENSATION
Produced on the ear.
It is the quantity of
SOUND ENERGY
flowing across unit
AREA in unit TIME.
It various from listener
to listener.
It is independent to
listener.
It is a
PHYSIOLOGICAL
quantity.
It is a PHYSICAL
quantity.
Its unit is SONE.  Its unit is Weber/m².

10. SOUND ABSORBING MATERIALS :
SR.
NO
SOUND
ABSORBING
MATERIALS
EXAMPLE
1 PORPUS
ABSORBERS
FIBER BOARDS, ROCK WOOD, WOOD
WOOL, SOFT PLASTERS, MINERAL
WOOLS, GLASS SILK, ASBESTOS FIBER
SPRAY.
2 CAVITY
RESONATORS
CAVITY RESONATOR CHAMBER.
3 RESONANT
ABSORBENTS
WINDOWS,DOORS, RIGID PLASTIC
BOARDS, SUSPANDED PLASTER
CEILINGS, GYPSUM BOARDS.
4 COMPOSITE
ABSORBERS
BOTTLE, EMPTY JAR, GLASS WOOD,
QUILT, SLAB, PERFORMED FIBER
BOARD.

11. REVERBERATION TIME :
 Definition:- The prolongation of sound wave in a hall
even though the source of sound is cut off is called as
REVERBERATION
 Sabine’s Formula:-
REVEBERATION TIME,
Where,
v- volume of hall
a- absorption coefficient
s- surface area
T= 0.167 V/ 𝑎𝑆

12. FACTOR AFFECTING ACOUSTICS OF
BUILDING :
 REVERBERATION TIME
 LOUDNESS
 FOCUSSING & INTERFERENCE EFFECT
 ECHO
 ECHELON EFFECT
 RESONANCE
 NOISE : 1) AIR BORNE NOISE
2) BORNE NOISE
3) INSIDE NOISE

13. REMEDIES TO CONTROL ACOUSTICS
 By providing windows & openings.
 By covering the floor with carpets.
 By using public address system like Loud Speaker.
 Avoid Curvature surface.
 To cover surfaces with Sound Absorbing materials.
 By decorating the walls with pictures & maps.

14. ADVANCE ENGINEERING
MATERIALS

15. CONTENT :
 Introduction
 Metallic Glass
 Bio-material
 Energy Materials

16. INTRODUCTION
 In the field of electrical , optical ,medical &
communication engineering new engineering
materials play a vital role.
 Today, In industries these materials are required for
good & high quality production.
 There are so many advance engineering materials
use today.
EXAMPLES: Metallic glass,
Bio-materials,
Different Energy materials.

17. METALLIC GLASS
 Metallic glasses share the properties of METAL &
ALLOYS.
 Metallic glass is non-crystalline , brittle and
transparent solid.
 Metallic glasses are to be made by various rapid
cooling techniques such as,
:-Spraying
:-Spinning
:-Laser Deposition

18. TYPES OF METALLIC GLASSES
1.Metal-Metal Glasses
Examples:-
: Ni-Nb
: Mg-Zn
: Cu-Zr
2.Metal-Metalloid
Glasses
Examples:-
:commercial metallic
glasses are usually
of this kind

19. PROPERTIES OF METALLIC GLASS:-
 They are Ductile,Malleable,Brittle & Opaque.
 Lighter in Weight
 Toughness & Hardness is very High
 High Elasticity
 High Corrosion Resistant
 Soft Magnetic Materials
 Strength is very High.

20. APPLICATION OF METALLIC GLASSES
Metallic glasses are used as Transformer Core
material in High power transformers.
 It used in making Cryothermometers , Magneto
resistance sensors & Computer memories.
 As magnetic properties of Metallic glasses, they
are used in making containers for Nuclear waste
disposal.
 It used in preparation of magnets for fusion
reactors & levitated trains.
 It used for making watch cases to replace Ni &
other metals, which can cause allergic reaction.
 It used in tap reorders as heads , in manufacturing
of springs & standard resistance.

21. BIO-MATERIALS
 Bio-Material:- A synthetic materials used to make
devices to replace part of living system Or to function
in intimate contact with living tissue.
 A variety of devices & materials are used in the
treatment of disease or injury.
 Bio-materials are classified into three groups:-
1. Bioinert
2. Bioactive
3. Biodegradable

22. Defination Application Examples
1. Bio-inert Minimal
interaction with
surrounding
tissues
Implant Applications Stainless
Steel,Titanium,Alumi
na.
2. Bioactive Interact with
surrounding hard
(bone) and soft
tissues
Bone Filling,Dental
Filling,Application.
Hydroxyapatite,Bioac
tive Glass,Glass
Ceramics.
3. Biodegradabl
e
Material slowly
dissolved into body
and replace the
damaged tissues
Scaffold application
Drug dilivery
Polylactic-
Polyglaycolic, acid
Copolymers

23. ENERGY MATERIAL
 Some energy Materials classified below:-
1. Solar Cell
2. Fuel Cell
3. Lithium Cell
4. Ultra Capacitor

24. SOLAR CELL
 Solar cell is a device that convert Solar energy
directly into Electric energy.
 Principle:
 Solar cell operate on the principle of Photovoltaic
action.
 A solar cell is basically a P-N junction which
generates EMF when solar radiation false on P-N
junction.

25. FIGURE: SOLAR CELL

26. APPLICATIONS OF SOLAR CELL
 Telecommunication PV systems & difficult to areas
like mountain tops , islands & deserts.
 To prevent corrosion of pipe , Bridges , etc.
 PV systems are also used to power railway signals ,
alarm systems , traffic lights & highway telephones.
 Remote radio & light beacons are powered by PV
systems.
 Interval of Time , Meteorological stations are
powered by PV systems.

27. ULTRASONIC

28. CONTENT
 Introduction to Ultrasonic
 Production of Ultrasonic waves
 Ultrasonic in Non-Destructive Testing
 Applications of Ultrasonic's

29. INTRODUCTION
 Classification of sound wave:-
1. Depends upon Frequency
2. Divided into 3 groups
Description Frequency range
Infra sound 0-20
Audible sound 20-20,000
Ultra sound >20,000-5M

30. PROPERTIES OF ULTRASONICS
 They have a high energy content (high freq)
 Speed of ultrasonic waves depends on frequency .
 Their wavelengths are small as a result , their
penetrating power is high.
 They can travel over long distances as a highly
directional beam.
 Polarization: can not be polarized

31. CREATING ULTRASONIC WAVE
 Ultrasonic waves are produced by the following
methods
1. Magneto-striction generator or oscillator
2. Piezo-electric generator or oscillator

32. MAGNETOSTRICTION METHOD
 This method is used to generate low frequency
ultrasonic waves
 Principle: Magnetostriction effect
When a magnetic field is applied parallel to the
length of a ferromagnetic rod made of
ferromagnetic materials such as iron or nickel, a
small elongation or contraction occurs in its length

33. MAGNETOSTRICTION METHOD
The change in length (increase or decrease) produced in
the rod depends upon
i) the strength of the magnetic field,
ii) the nature of the ferromagnetic materials
iii) does not depend of the direction of the field.

34. MAGNETOSTRICTION METHOD
 Construction
b
c
e
The experimental arrangement is shown in Figure

35. MAGNETOSTRICTION METHOD
 XY is a rod of ferromagnetic materials like iron or
nickel. The rod is clamped in the middle.
 The alternating magnetic field is generated by
electronic oscillator.
 The coil L1 wound on the right hand portion of the
rod along with a variable capacitor C.
 This forms the resonant circuit of the collector tuned
oscillator. The frequency of oscillator is controlled
by the variable capacitor.
 The coil L2 wound on the left hand portion of the
rod is connected to the base circuit. The coil L2
acts as feed –back loop.

36. Working
• When High Tension (H.T) battery is switched on, the
collector circuit oscillates with a frequency,
f =
• This alternating current flowing through the coil L1
produces an alternating magnetic field along the length
of the rod. The result is that the rod starts vibrating due
to magnetostrictive effect.
1
1
2 L C
MAGNETOSTRICTION METHOD

37. The frequency of vibration of the rod is given by
f =
where l = length of the rod
E = Young’s modulus of the rod material and
 =density of rod material
• The capacitor C is adjusted so that the frequency of the
oscillatory circuit is equal to natural frequency of the rod
and thus resonance takes place.
• Now the rod vibrates longitudinally with maximum
amplitude and generates ultrasonic waves of high
frequency from its ends.

E
l
P
2
MAGNETOSTRICTION METHOD

38.  Advantages
1. The design of this oscillator is very simple and its
production cost is low
2. At low ultrasonic frequencies, the large power output
can be produced without the risk of damage of the
oscillatory circuit.
1.It has low upper frequency limit and cannot generate
ultrasonic frequency above 3000 kHz (ie. 3MHz).
2.The frequency of oscillations depends on temperature.
3.There will be losses of energy due to hysteresis and eddy
current.
 Disadvantages
MAGNETOSTRICTION METHOD

39. PIEZO ELECTRIC METHOD
 If mechanical pressure is applied to one pair of opposite
faces of certain crystals like quartz, equal and opposite
electrical charges appear across its other faces. This is
called as piezo-electric effect.
 The converse of piezo electric effect is also true.
 If an electric field is applied to one pair of faces, the
corresponding changes in the dimensions of the other
pair of faces of the crystal are produced. This is known
as inverse piezo electric effect or electrostriction.
Principle : Inverse piezo electric effect

40. The circuit diagram is shown in Figure
Piezo electric oscillator
PIEZO ELECTRIC METHOD

41.  The quartz crystal is placed between two metal plates A
and B.
 The plates are connected to the primary (L3) of a
transformer which is inductively coupled to the electronics
oscillator.
 The electronic oscillator circuit is a base tuned oscillator
circuit.
 The coils L1 and L2 of oscillator circuit are taken from the
secondary of a transformer T.
 The collector coil L2 is inductively coupled to base coil L1.
 The coil L1 and variable capacitor C1 form the tank circuit
of the oscillator.
PIEZO ELECTRIC METHOD

42.  When H.T. battery is switched on, the oscillator produces high
frequency alternating voltages with a frequency.
 Due to the transformer action, an oscillatory e.m.f. is induced in the
coil L3. This high frequency alternating voltages are fed on the plates
A and B.
 Inverse piezo-electric effect takes place and the crystal contracts and
expands alternatively. The crystal is set into mechanical vibrations.
 The frequency of the vibration is given by
f =
112
1
CL
f



E
l
P
2
where P = 1,2,3,4 … etc. for fundamental,
first over tone, second over tone etc.,
E = Young’s modulus of the crystal and
ρ = density of the crystal.
Working
PIEZO ELECTRIC METHOD

43. Advantages
 Ultrasonic frequencies as high as 5 x 108Hz or 500 MHz
can be obtained with this arrangement.
 The output of this oscillator is very high.
 It is not affected by temperature and humidity.
Disadvantages
 The cost of piezo electric quartz is very high
 The cutting and shaping of quartz crystal are very
complex.
PIEZO ELECTRIC METHOD

44. APPLICATION OF ULTRASONIC WAVES
SONAR
 SONAR is a device which stands for Sound Navigation and
Ranging.
 It is based on the principle of echo sounding.In this
technique high-frequency ultrasonic waves are used.
 When ultrasonic waves are transmitted through water,they
get reflected by the objects under water.the change in
frequency of the echo signal due to the Doppler effect helps
us to determine the velocity,distance and direction of objects.
 Using sonar the distance and direction of submarines,depth
of sea ,depth of rocks in the sea,the shoal of fish in the
sea.,can be determined.
44

46. ULTRASONICS IN NON-DESTRUCTIVE TESTING
 Ultrasonics used in Non-Destructive Testing.
 It is defined as the process of testing the material without
causing any damage or reducing the service life of the
component.
 NDT may be classified as:
(1)To incress serviceability
(2)To improve productivity and to increse the profits
(3)To increse safety
46

47. OTHER APPLICATION OF ULTRASONICS
 Ultrasonic waves used in industry for
drilling,cutting,welding,soldering.
 It is uesd in medical for diagostic purpose and
therapetic.
 It is also used in science and engineering.
 It used in medicine.
47