Transcript
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Electro physical agents
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Structure and Properties of Matter
� Matter means material such as Pen, Rod,ect.
� Material or matter is made up of atoms.
ATOM:
� Atom is defined as the smallest indivisible part
of matter.
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Structure of atom
� The Atom can be described having a central nucleussurrounded by cloud of electrons revolving in definite orbits.
� The Nucleus: This is the central part of the atom, the two
most important particles are the proton and the neutron.
� Proton: it is positive charged particle present in the nucleus,because of this the charge of nucleus is positive.
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Structure of atom
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Structure of atom
� Neutron it is neutrally charged particle
present in the nucleus.
�
Electron negative charged particles revolvingin orbits around the nucleus.
� In neutral atom their number is equal to
number of protons.
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Formation of Compounds
� A Compound is a substance formed by the
union of two or more elements.
� Atoms combine to form molecule.
� Molecules combine to form elements.
�Elements combine to form compounds.Example: Sodium chloride (Common Salt)
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Electro Magnetic Radiation
- when ever any object is heated the electrons
from lower orbit takes up energy and goes to
higher orbit.
- After sometime the electrons return back to its
original orbits, while coming back they loose
energy in the form of light called as electron
magnetic radiation.
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Electro Magnetic Radiation
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Different kinds of rays
� X-rays.
� Infrared
�Visible rays-rays coming from sun ,in the earlymorning.
� U V rays
�Gamma rays
� Radio rays
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Different kinds of rays
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Forces
� Force is defined as push or pull exerted by one object
on other object.
� In a molecule we have two types of forces
- Cohesive force.- Kinetic force.
� Cohesive force-attractive force between two atoms.
� Kinetic force-force required to move atoms, or the
force with which atom can move.
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Cohesive force - Kinetic force.
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States of matter
2.Liquid: Cohesive force is present and it is less,
kinetic force is increased, liquid will take the
shape of object.
If energy is supplied to liquids they transform
into gases.
3.Gas : Cohesive force is very less, kinetic force
is more.
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States of matter
example: Ice (solid) to water (liquid) to vapor
(gas).
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Latent heat:
Latent heat:� The energy required to change from one state
to another state is called as latent heat.
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Electrical charges
� Atom have properties of losing or gaining
electrons.
�
When an atom of an element loose electron itbecomes positive (cation).
� When an atom of an element gains electron it
becomes negative (anion).
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Transmission of heat
Transmission of heat takes place in three forms
1. Conduction.
2. Convection.3. Radiation.
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Transmission of heat
1. Conduction: takes place
in case of metals. Heat
transfer from high
temperature to low
temperature.
s
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Transmission of heat
2. Convection: transmission
of heat that is taking place
in liquids.
The electrons at bottom are
heated and they will go up,
the atom at the top will
come down.
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Transmission of heat
3. Radiation: Transmission of heat taking place
in gases is called as radiation.
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Transmission of heat
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Physical Effects of heat
1. Expansion: expansion is the result of
increased kinetic energy producing a greater
vibration of molecules.
2. Change in state: heat causes changes from
one state to another.
solids to liquid and liquid to gas.
3. Acceleration of chemical reaction: heat
increases the chemical reaction.
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Physical Effects of heat
4. Electron magnetic radiation: when ever any
object is heated the electrons from lower orbit
takes up energy and goes to higher orbit after
sometime the electrons return back to its
original orbits, while coming back they loose
energy in the form of light called as electron
magnetic radiation.
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Physical Effects of heat
5. Decrease in viscosity: heating increases the
kinetic movement of the molecules and
reduces cohesive forces this makes fluid less
viscous.
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Electricity
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Introduction
� Electricity: Flow of electrons is called as electricity.
� Conductors: These are the elements whose atoms
have free electrons in their outer orbits.
� They allow the electrons to pass through them.
� Electric current pass through conductors easily.
Example: Metals like Iron, human being.
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Introduction
� Non conductors or insulators: Elements in
which the atoms have completely filled
electrons In their outer orbit.
� They will not allow the electrons to pass
through them.
� Electric current can not pass through
insulators. Example: wood, clothes.
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Static Electricity
� Static Electricity: When the charges are held on thesurface of a body it is called as static electricity.
Production:
� The simplest way of producing a static electriccharge is to rub two suitable materials together.
� If two insulators such as Glass and Flannel arerubbed together, a positive charge is produced on
the flannel and a negative charge on the glass.
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Static Electricity
� This is because electrons are transferred from
the superficial atoms of the flannel to the
surface of the glass.
� As the materials involved are insulators, the
charges are held on the surfaces of the objects
and spread themselves evenly over the
surfaces.
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Static Electricity
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Static Electricity
Charged body and its electric field
� The charged body is continually seeking to attain
neutral state, if negative by loosing electrons, and if
positive by gaining electrons.
� This creates a zone of influence (electric field).
� This field is made up of lines of force surrounding the
body.
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Static Electricity
� They show certainproperties.
- The lines of force are
straight.- Lines of force repel one
another.
- Lines of force pass more
easily through conductorsthan through insulators.
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Static Electricity
� Potential: electrical potential is the electricalcondition of the body.
� Bodies with excess of electrons are negative.
� Bodies with less electrons are positive.
� Capacitance: Ability of a body to hold electriccharge.
� It depends on material and surface area of thebody.
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Static Electricity
Difference of potential (Potential difference)
� A difference of potential exists between similarbodies charged with different quantities of
electricity.� If a conducting connection is made between two
bodies electrons will flow from the more negativebody to less negative body.
�
The force producing the movement is Electromotiveforce.
� Electrons flow until both objects are at the samepotential.
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Current Electricity
Electromotive force (EMF):
The force which causes electrons to move along
a conductor is called as EMF
.Resistance:
The conductor through which electrons have to
flow offers some resistance to their flow.
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Current Electricity
Electrical Resistance depends on
- material
- length of the material
- cross sectional area
Magnitude of Current (Intensity);
The intensity or magnitude of current (i) is the rate of
flow of electrons through the conductor per second.
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Break Time
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Electrical Energy
Anand kumar Anand kumar
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All of us agree the importance of electricity in our daily
lives.
But what is electricity?
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Electricity!Everything in the world is made up
of atoms. Each atom has smaller
parts in it. One of those parts iscalled electrons. Electrons can
move from atom to atom. When
electrons move quickly from one
atom to another is it calledElectricity!
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ELECTRICITY
There are two areas that can be studied
STATIC ELECTRICITY CURRENT ELECTRICITY
This section deals with
stationary charge.This section deals with
moving charge.
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Static Electricity
� The build up of an electric charge on the surface of an
object.
� The charge builds up but does not flow.
� Static electricity is potential energy. It does not move. It isstored
- --
--
-
- ++++
+
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Examples of Static Electricity
�
Take a comb or plastic pen and ru
b it on almost any pieceof fabric, it will acquire a small electric charge
� If placed near small pieces of paper, they will be attracted
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When two objects rub against each other electrons transfer and build up on an
object causing it to have a different charge from its surroundings.
Like the shoes rubbing against the carpet. Electrons are transferred from the
carpet to the shoes.
Examples of Static E lectricity Examples of Static E lectricity
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CURRENT ELECTRICITY
Current: The flow of electrons from one place to another.
Measured in amperes (amps)
Electricity that moves«Electricity that moves«
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Current Electricity
� There are two types of currents
� Direct current
� Alternating current
� Direct current given ( DC)
charges moving continually in one direction
eg using batteries
� Alternating current given ( AC)
the direction of charge flow is reversing or alternatingdirection continually
eg using mains power at 50 Hz AC
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ELECTRIC CIRCUIT
A path that allows electrons to flow from negative to positive
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1.series circuit 2. parallel circuit
What is aseriescircuit?
A series circuit is one which provides a single pathway forthe current to flow. If the circuit breaks, all devices usingthe circuit will fail.
There are two types of circuits
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What is a parallel circuit?
A parallel circuit has multiple pathways for the current to flow. If
the circuit is broken the current may pass through other pathwaysand other devices will continue to work.
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Electricity
� The unit of charge is the coulomb (C)
� The charge on an electron is -1.6x10-19 C
� The charge on a proton is +1.6x10-19 C
� One coulomb is the flow of 6.25x1018 electrons� Electric current is the rate of flow of electrons
� The unit of current is the Ampere (Amp)
� One Amp is the flow of one coulomb in one second
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Electrically, materials are classified
as
Insulators Conductors
Semiconductors
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� Conductors have a lower resistance.
� Examples: metals, copper, silver.
� Pure water does not conduct well, butwater with dissolved salts does conduct
A conductor is a material that current can pass through easily,A conductor is a material that current can pass through easily,like metalslike metals
C onductorsC onductors
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Semiconductors
� Semiconductors allow electrons to flow onlyunder certain conditions eg silicon. For siliconthe conductivity is increased by the additionof small amounts of elements such as arsenic
or boron
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Transmission of electricity through
solids,eletrolytes,gasesHeat:Heat:--
Heat is the movement of thermal energy from aHeat is the movement of thermal energy from a
substance at a higher temperature to another substance at a higher temperature to another substance at a lower temperature.substance at a lower temperature.
Heat moves in only one direction:Heat moves in only one direction:
Under normal conditions and in nature, heatUnder normal conditions and in nature, heat
energy will always flow the warmer object to theenergy will always flow the warmer object to the
cooler objectcooler object
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How HEAT moves
� Thermal energy in the form of heat can move
in three ways:
1. Conduction (solids)
2. Convention (liquids and gases)
3. Radiation
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Conduction
� The transfer of heat from one particle of matter to another by direct particle contact.
� Conduction occurs primarily in solids because
the particles are tightly packed together.� The particles themselves DO NOT change
positions.
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Radiation
� Radiation: the transfer of (thermal) energy byelectromagnetic waves.
� Radiation does not require matter to transferthermal energy.
� Example: ± Charcoal grill ± Hot tin roof ± Burner on a stove top
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Household Electricity
� Cords
� Computers
� TV
� Microwave
� Stove
What are some types of household electricity?What are some types of household electricity?
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Safe Use Of Electricity
� Dont pull cords
� D
ont put metal in anelectrical appliance
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How Electricity Impacts Today's
Life
We use electricity for
light, heat,
transportation,
everything!
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Dangers of static and
current electricity
Precautions Precautions
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� Electricity is essential to
modern life
�Some employees work with electricity directly
� Some indirectly
�Electricity is a seriousworkplace hazard
Dangers of static and current Dangers of static and current
E lectricity E lectricity
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Electrical Shock
� A sudden and accidental stimulation of the
bodys nervous system by an electrical current
� Current will flow through the body
when it becomes part of an electrical circuit
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Other Injuries
� Burns
� Falls
� Injuries when machinery starts suddenly
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Electrical Burns
� Current passing through tissue generates
extreme heat
� Skin damage at entry and exit
� Internal tissue damage
� Result from arcs or flashes
�
Thermal burns from overheated wires orequipment or fires
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Falls
� Initiated by a shock
� Muscles contract involuntarily
� Worker can lose balance and fall
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Machinery Injuries
� Unexpected activation
� Shock
�
Pinch� Crush
� Shear
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A GOOD T HING TO KEEP IN MIND!
Precautions Precautions
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S AFETY SHIELDS ARE EYE INSURANCE!
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S AFETY SHOE S ARE NOT FOR
DEFEAT!
HEARING PROTECTION IS FOR
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HEARING PROTECTION IS FOR
WINNERS!
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Thermal Energy
� Units of heat and temperatures
� Physical effects of heat
� Transmission of heat
Anand kumar Anand kumar
Temperature
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Temperature
1. Temperature is related to theaverage kinetic energy of the
particles in a substance.
Cup gets cooler while
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Heat
a. The flow of thermal energy
from one object to
another.
b. Heat always
flows from warmer
to cooler objects.Ice gets warmerwhile hand gets
cooler
Cup gets cooler whilehand gets warmer
Units of Heat
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83
Units of Heat
� The SI unit is the joule (J),
which is equal to Newton-metre (Nm).
�
Historically, heat was measured in terms of theability to raise the temperature of water.
� The calorie (cal): amount of heat needed to
raise the temperature of 1 gramme of water by1 C0 (from 14.50C to 15.50C)
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Heat TransferConduction, Convection, and Radiation
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Review: Temperature
� Temperature is:
± The quantity that tells how hot or cold something
is compared with a standard
± A measure of the average kinetic energy of themolecules of a substance
� Temperature IS NOT energy
±If something has a higher temperature, itsmolecules have more energy, but temperature is
not the same thing as energy
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Review: Thermal Energy
� Thermal Energy is:
± The total energy (kinetic plus potential) of the
particles that make up a substance.
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Review: Heat
� Heat is:
± The thermal energy that flows from an object at
higher temperature to one at lower temperature,
commonly measured in calories or Joules.
� Heat is exchanged until thermal equilibrium is
reached
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A Comparison
Temperature Thermal
Energy
Heat
Measuresaverage
kinetic energy.
The sum of allthe
kinetic
energies.
The flow of thermal
Energy.
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Conduction
Conduction: How does this method
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Conduction: How does this method
work?
� Conduction takes place within materials and
between different materials that are in direct
contact.
Conduction: How does this method
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Conduction: How does this method
work?
� Conduction is explained by collisions between atomsor molecules
± Warmer atoms move more violently (they have moreenergy). These warmer atoms bump into nearby atoms
and transfer energy, resulting in an increase in the motionof the nearby atoms.
Conduction: How does this method
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Conduction: How does this method
work?
� Free electrons that drift through the metal jostle and transfer energy by colliding withatoms and other free electrons
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Conduction: What moves?
� Conduction involves the transfer of energy
from molecule to molecule; energy moves
from one place to another but molecules do
not.
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Conduction: Heat Conductors
� Materials that conduct heat well areknown as heat conductors.
± Metals are the best heat conductors sincemetals have loose outer electrons
± If you touch a piece of metal that is at roomtemperature it often "feels cold." This isbecause metal is a good conductor of heat.It quickly conducts heat away from yourbody.
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Conduction: Heat Insulators
� Poor conductors of heat, such as styrofoam and air,are called good insulators.
± Liquids and gases are in general good insulators. Porousmaterials with lots of small spaces are good insulators.
± A blanket on your bed does not provide your body withheat. It just slows the conduction of your body heat to thecolder air.
± Insulation delays heat transfer, it can not prevent it!
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Convection
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Convection: How does this method
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Convection: How does this method
work?
� When a fluid is heated, itexpands and becomes lessdense; since it is less dense, itrises.
�
Warmer fluid floats on top of cooler fluid.
� Cooler fluid then moves to thebottom and the processcontinues.
� Convection currents keep a
fluid stirred as it is heated.
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Convection: What Moves
� Convection involves the movement of a fluid;
if there is not a fluid, convection cannot occur.
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Convection: Example
� Convection currents stir the atmosphere andproduce winds.
� Convection currents are produced by unevenheating of the air near the surface of the earth.
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Convection: Example
� Land warms and cools more quickly than water. Thusconvection currents are often evident at the shore insea breezes and lands breezes.
d
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Radiation
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di i h
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Radiation: What Moves
� With radiation, only energy moves from the
warmer object to the cooler object.
R di i W l h E i d
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Radiation: Wavelengths Emitted
� All objects continually emit radiant energy in amixture of wavelengths. Objects at lowertemperatures emit longer waves and objects athigher temperature emit waves of shorter
wavelength. Objects of everyday temperatures emitwaves mostly in the longer wavelength end of theinfrared region.
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Radiation: Absorption and Reflection
are Opposite Processes
� A good absorber of radiant energy reflects very little
radiant energy and appears dark. A perfect absorberreflects no radiant energy and appears perfectlyblack.
� Good reflectors of radiant energy are poor absorbers.
Light colored objects reflect more light and heat thandarker colored objects. This is why wear lightercolored clothing in summer to stay cool.
H T f f M
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Heat Transfer for a Mouse
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What Is the Electromagnetic Spectrum
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What Is the Electromagnetic Spectrum
(EM)?� The electromagnetic spectrum is the complete
range of electromagnetic waves placed in
order of increasing frequency.
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VISIBLE LIGHT
(part of EM spectrum)
The Electromagnetic Spectrum
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More than meets the eye!
Examples from Space!
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W l th
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Wavelength
� The distance from one wave crest to the next
� Radio waves have longest wavelength and Gamma rays
have shortest!
W l th U it
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Wavelength Units
� Meters (like on last slide and in book, p. 613)
± More commonly in nanometers (1 nm = 10-9
meters)� Angstroms still used
± Named for Swedish Astronomer who first named
these wavelengths
± 1 nanometer = 10 Ao
How light or electromagnetic radiation is
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g g
used in Astronomy
� Astronomers use a tool called aspectroscope to separate starlight into itscolors in this way, they can tell what a staris made of, its temperature, luminosity andso on
� Astronomers can look at astronomical
objects at different wavelengths
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Spectra of a
Star
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WHITE LIGHT
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WHITE LIGHT
Adding color makes WHITE Deleting color
makesBLACK
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MANY COLORS = WHITE
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�Reflection�Retraction
�Absorption�Radiation laws
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HOW LIGHT MOVES
Straight Line unless altered by what moving in.
LIGHT SCATTERS AS GOES
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LIGHT SCATTERS AS GOES
Light scatters and looses energy the furtheraway from its source.
SCATTERING
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SCATTERING� Light released and spreads in all directions.
± Why room is even with light.
± Sky blue: shortest wavelengths, spread more.
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R EFLECTIONR EFLECTION
REFLECTIONREFLECTION
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REFLECTIONREFLECTION
Light bounces off surface at same angle ithits.
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ABSORPTION
ABSORPTION
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ABSORPTION
� LIGHT IS TAKEN IN BY AN OBJECT (MATTER)AND HOLDS IT.
� ENERGY TRANSFERRED FROM LIGHT TO HEAT.
� AIR PARTICLES DIMINISH LIGHT.
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INTERACTS
WITH MATTER
TRANSMISSION
� Light goes straight unless changes what it
travels through.
� Travels through matter:
gases (air)
liquids (water)
solid (glass)
TRANSMISSION
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Terms for mediums
� Transparent : allows all light through.
� Translucent : allows some light through.
� Opaque : allows no light through.
Wh Li ht St ik Obj t
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When Light Strikes an Object
When light strikes
an object, the lightcan be reflected,transmitted, or
absorbed.
REFRACTION
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REFRACTION
� The change in direction and speed.
� Moving from water to air, light changesangles and speed of travel.
Refraction of Light
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Refraction of Light
When light rays enter a
medium at an angle,
the change in speedcauses the rays to
bend, or change
direction.
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LIGHTLIGHT -- WHAT WE SEEWHAT WE SEE
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LIGHTLIGHT WHAT WE SEEWHAT WE SEE�LIGHT - energy by wavelengths at a level we can see.
� EM Spectrum- variety of wavelengths and frequency.
Light is small band within.
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Heat and Internal Energy� Internal EnergyU is the total energy associated with the
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� Internal EnergyU is the total energy associated with themicroscopic components of the system
± Includes kinetic and potential energy associated with therandom translational, rotational and vibrational motion of theatoms or molecules
± Also includes the intermolecular potential energy
± Does not include macroscopic kinetic energy or externalpotential energy
� Heat refers to the transfer of energy between a systemand its environment due to a temperature differencebetween them
± Amount of energy transferred by heat designated by symbol Q
± A system does not have heat, just like it does not have work(heat and work speak to transfer of energy)
Units of Heat� The historical unit of heat was the calorie
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The historical unit of heat was the calorie
± A calorie is the amount of energy necessary to raise the
temperature of 1 g of water from 14.5°C to 15.5°C
± A Calorie (food calorie, with a capital C) is 1000 cal
� Since heat (like work) is a measure of energy transfer, its
SI unit is the joule
± 1 cal = 4.186 J (Mechanical Equivalent of Heat)
± New definition of the calorie
� The unit of heat in the U.S. customary system is the
British thermal unit (BTU) ± Defined as the amount of energy necessary to raise the
temperature of 1 lb of water from 63°F to 64°F
More About Heat
� Heat is a microscopic form of energy transfer involving
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� Heat is a microscopic form of energy transfer involvinglarge numbers of particles
� Energy exchange occurs due to individual interactions of the particles
± No macroscopic displacements or forces involved
� Heat flow is from a system at higher temperature to one
at lower temperature ± Flow of heat tends to equalize average microscopic kinetic
energy of molecules
� When 2 systems are in thermal equilibrium, they are at
the same temperature and there is no net heat flow� Energy transferred by heat does not always mean there is
a temperature change (see phase changes)
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Ideal Gas Law
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Ideal Gas Law
PV=nRTZ
n = Mass
R = Universal gas constantT = Temperature
Z = Supercompressability
(P1V1/T1)Z1=(P2V2/T2)Z2
Ideal Gas Law
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� An Ideal Gas (perfect gas)is one which obeysBoyle's Law and Charles' Law exactly.
� An Ideal Gas obeys the Ideal Gas Law (General gasequation):
PV = nRTwhere P=pressure, V=volume, n=moles of gas,T=temperature, R is the gas constant which isdependent on the units of pressure, temperatureand volume
Boyles Law
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y
� At constant temperature, the volume of agiven quantity of gas is inversely proportionalto its pressure : V 1/PSo at constant temperature, if the volume of agas is doubled, its pressure is halved.ORAt constant temperature for a given quantity
of gas, the product of its volume and itspressure is a constant : PV = constant, PV = k
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At constant temperature for a given quantity of gas :
PiVi = PfVf where Pi is the initial (original) pressure, Vi is its initial
(original) volume, Pf is its final pressure, Vf is its final
volume
Pi and Pf must be in the same units of measurement(eg, both in atmospheres), Vi and Vf must be in the
same units of measurement (eg, both in litres).
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All gases approximate Boyle's Law at high
temperatures and low pressures. A hypothetical gas
which obeys Boyle's Law at all temperatures and
pressures is called an Ideal Gas. A Real Gas is onewhich approaches Boyle's Law behaviour as the
temperature is raised or the pressure lowered.
Boyles Law
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y
P1V1=P2V2
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At constant pressure for a given quantity of gas : Vi/Ti = Vf/Tf where Vi is the initial (original) volume, Ti is its initial (original)
temperature (in Kelvin), Vf is its final volme, Tf is its final
tempeature (in Kelvin)
Vi and Vf must be in the same units of measurement (eg,both in litres), Ti and Tf must be in Kelvin NOT celsius.
temperature in kelvin = temperature in celsius + 273
(approximately)
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All gases approximate Charles' Law at high temperaturesand low pressures. A hypothetical gas which obeys
Charles' Law at all temperatures and pressures is called an
Ideal Gas. A Real Gas is one which approaches Charles'
Law as the temperature is raised or the pressure lowered
Charles Law
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V1/V2=T1/T2
P1V1/T1=P2V2/T2
Latent Heat
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When a solid melts or a liquid boils, energy must
be added but the temperature remains
constant! (This can be explained by
considering that it takes energy to break thebonds holding the material together.)
The amount of energy it takes to melt or boil a
certain amount of material is called a latentheat.
Latent Heat
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For water, the latent heat of f usion (heat
needed to melt ice to water) is 79.7 cal/gm.
For water, the latent heat of vaporization (heat
needed to boil water) is 540 cal/gm.
For alcohol, the latent heat of vaporization is
less at 204 cal/gm.
Introduction superficial heat and cold therapy
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� Physiological effects that produce pain relief direct result of the tempelevation on the tissue and cellular function.
� And through a reflex reaction
� Heat reduce pain & muscle spasm while decreasing joint stiffness and
contractures
� Produce hyperemia , speed metabolic process & hematoma resolution
� Heat is useful for bursitis and tensoynovitis along with superficial
thrombophlebitis
� Causes an introduction of reflex vasodilatation
Superficial heat
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� While the physical properties differ, none of
these agents are able to overcome the
combination of skin tolerance , tissue thermal
conductivity , and the body s response toproduce localized temperature elevations of
more than a few degrees at depths of a few
centimeters
� Conduction ,conversion & convection
Heat indications
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� Pain
� Muscle spasm
� Decreased joint stiffness and contractures
� Myofascial pain and fibromyalgia
� Production of hyperemia
� Acceleration of metabolic process
� Hematoma resolution
� Bursitis and tenosynovitis
� Superficial thrombophlebitis
� Induction of reflex vasodilatation
Heat contraindication
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� Acute inflammation , abscess, trauma, edema orhemorrhage
� Bleeding disorders
�
Insensitivity� Inability to communicate or respond
� Poor thermal regulation
� Areas of malignancy
� Ischemia (inadequate blood supply)
� Atrophic skin & scar tissue
Superficial cold-cryotherapy
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� Reduce blood flow
� Decreases metabolic activity
� Lessens muscle tone spasm
� Decreased swelling� Inhibits spasticity and clonus
� Increase gastrointestinal motility
� Slows nerve conduction� Produces analgesia
Cryotherapy
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� Restricted to superficial agents that are
inexpensive , but effective including:
� -ice ,cold water, refrigerated units, vaporizing
liquids (vapo-Coolant spray ), and chemicalpacks
� Chilling cause an initial period of
vasoconstriction until subcutaneous tissuesreach 15 degree C
cryotherapy
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� Thereafter , vasodilatation occur ,howevervessels are still constricted compared tonormal
�
Temp to 13- 15 degree C for 10 to 20 minutesare used
� Cold should be provide just long enough toprevent swelling and bleeding but prolonged
use should be avoided as cold can retardhealing
Cold indications
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� Musculoskeletal trauma
� Edema / hemorrhage control & analgesia
� Pain
� Muscle spasm
� Spasticity
� Adjunct in muscle re-education
� Reduction in metabolic activity
Cold contractions
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� Ischemia
� Cold intolerance /hypersensitivity
� Reynaud's
� Severe cold pressor responses
� Cold allergy
� Insensitivity
Cryotherapy cold therapy
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� Cold modalities range in temp between 32 degree F65 F
� Heat is removed from the body & absorbed by the cold
modality
� Tissue temperature is LOWERED
� Cold therapy applied is thought to activate a mechanism usedto conserve heat in the bodys core
� This mechanism triggers a series of metabolic & vascular
events that produce the beneficial effects of cryothorepy .
� Can be used during all stages of healing
Pain control
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� Cold therapy acts as a counterirritant
� Cold application affects pain perception &
transmission by:
� -interrupting pain transmission (stimulate-diameter A-beta n. fibers)
� Decreasing n . Conduction velocity
� Reducing m. spasm
� Reducing or limiting edema
Systemic effects of cold exposure
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� If circulating blood temperature decrease to 0.2 degrees,thenthe hypothalamus(bodys thermoregulatory center) kicks in
� General vasoconstriction in response to cooling of the
posterior hypothalamus.
� Decreased respiratory and heart rates� - Heart rate decreases (wants to localize the cold area)
� Shivering &increased muscle tone
� -if the heart decrease too much where the core temperature.
reaches hypothermia
Application of Cryotherapy
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� Ice massage: should not be applied during Acute inflammatory stage as itis not compatible with compression
� 5-15 min.-reduces pain ,desensitizes the trigger points
� Vigorous ice massage
� Ice pack : type of ice- cubed,flaked
�Commercial cold packs chemical reusable
_ Be aware of frostbite;use insulating layers between cryo-cuff/Polarcare:provide approx.40mm hg
Cold water immersion
- Ice bucket 40 degrees 50 degree F
- Whirlpool 50 degrees 60 degreesF
Vapour coolent spray: superficial rapid cooling through evoporation,vertticallyno temperature change below epidermis,will numb the area breifly(trigger points ).
T E N S
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What is TENS?
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� Transelectrical Neuro Stimulation
� The application of low voltage electrical pulses to
the nervous system through the skin via
electrodes
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Mechanism of action
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� Gate control theory: Conventional
� Natural opiates: Acupuncture like settings
� Primary indication: PAIN
� An Approach to pain control
± Trancutaneous Electrical Nerve Stimulation:
± Any stimulation in which a current is applied across
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± Any stimulation in which a current is applied acrossthe skin to stimulate nerves
± 1965 Gate Control Theory created a greatpopularity of TENS
± TENS has 50-80% efficacy rate
± TENS stimulates afferent sensory fibers to elicit
production of neurohumneral substances such asendorphins, encephalin and serotonin (i.e. gatetheory)
CONTRAINDICATIONS
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� 1st Trimester pregnancy
� Epilepsy avoid head and neck
� Eyes
� Open skin
� Over the chest if patient has any cardiac condition
� High BP� High fever
� Tuberculosis
� Numb skin
� Carotid sinus
Indications
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± Control Chronic Pain
± Management post-surgical pain
± Reduction of post-traumatic & acute pain
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Precautions
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± Can mask underlying pain
± Burns or skin irritation
± prolonged use may result in muscle
spasm/soreness
± caffeine intake may reduce effectiveness
± Narcotics decrease effectiveness
Biophysical Effects
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�
Primary use is to control pain through Gate ControlTheory
� May produce muscle contractions
� Various methods
± High TENS (Activate A-delta fibers) ± Low TENS (release of F-endorphins from pituitary)
± Brief-Intense TENS (noxious stimulation to active C
fibers)
Common Modes of TENS for
Nerve Stimulation
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Nerve Stimulation
CONVENTIONAL Frequency 10-
100 Hz
Amplitude low
to medium
Place electrodes
at perimeter
Of pain, over
nerve Segment
Pt perceives a
distinct
parethesia on
painful region
or segment
STRONG low
rate
Frequency < 10
Hz Pulse
duration 100-
300usec
Over nerve
related to m in
or remote
Uncomfortable
rhythmic
muscle
contractions
MODES
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Brief intense Freq. 60-150Hz.Pulse duration50-
250usec
Over nerve relatedto m in or remote
from pain
Uncomfortabletetanic
contractions that
fatigues, at patient
tolerance
Pulse Burst Modulated Freq.:
HIGH 60-100, Low
.5-4Hz 50-200usec
As above Weak to strong
intermittent
tetanic muscle
contract and
paresthesias
MODES
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MODULATED Freq, Pulse
duration and
Amplitude Are
modulated
separate or
together
Any of previously
Mentioned sites
Weak to strong
sensation, with or
without muscle
contraction
Hyperstimulation Freq. 1-100
Pulse Duration Up
to 500 ms
Amplitude High
Accupuncture
points
Sharp burning
sensation at
tolerance. No
muscle contraction
Acceptable Electrode Placement
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� D
irectly over pain� Superficial peripheral nerve
� Over dermatomes
� Acupressure point
� Over myotomes
� Motor points
� Placement can be unilateral, bilateral or crossed.
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ULTRASOUND
A Deep Thermal & Non-thermal
Mechanical Modality
What is Ultrasound?
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� May be used for diagnostic imaging,
therapeutic tissue healing, or tissue destruction
� Thermal & Non-thermal effects
� We use it for therapeutic effects
� Can deliver medicine to subcutaneous tissues
(phonophoresis)
Ultrasound
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� Waveform
± Therapeutic ultrasound waves range from 750,000
to 3,000,000 Hz (0.75 to 3 MHz)
Transducer
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�
A device that converts one form of energy to another� Piezoelectric crystal: a crystal that produces (+) and (-)
electrical charges when it contracts or expands
± Crystal of quartz, barium titanate, lead.
� Reverse (indirect) piezoelectric effect: occurs when analternating current is passed through a crystal resulting incontraction & expansion of the crystal
± US is produced through the reverse piezoelectric effect
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Types of Current
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� Direct Current: the uninterrupted unidirectional flow
of electrons
�
Alternating Current: the uninterrupted bidirectionalflow of electrons
± Ultrasound is produced by this type of current flowing
through a piezoelectric crystal
� Pulsed Current: the flow of electrons interrupted by
discrete periods of noncurrent flow
� Longitudinal waves travel in solids & liquids
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�
Transverse waves cannot pass throughfluids; found in the body only when
ultrasound strikes bone
Frequency� Frequency: number of times an event occurs in
1 second expressed in Hertz or pulses per
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1 second; expressed in Hertz or pulses per
second
± Hertz: cycles per second
± Megahertz: 1,000,000 cycles per second
�
In the U.S., we mainly use ultrasound frequencies of 1, 2and 3 MHz
� 1 = low frequency; 3 = high frequency
�
q frequency = o depth of penetration� o frequency = sound waves are absorbed in
more superficial tissues (3 MHz)
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Coupling Agents
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�
Optimal agent distilled H20(.2% reflection)
± Improperly coupled head causes o temp.
� Types of agents:
± Direct
± H20 immersion ± Bladder
Direct Coupling
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� Effectiveness is q if body part is hair, irregularshaped, or unclean
� Must maintain firm, constant pressure
� Various gels utilized
Water Immersion
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�
Used for odd shaped parts� Place head approx. 1 away from part
� Operators hand should not be immersed Nometal on part or operators hand
� Ceramic tub is recommended
� If nondistilled H20 is used, intensity can be o.5 w/cm2 because of air & minerals
� Dont touch skin except to briefly sweep skinwhen bubbles form
Bladder
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� H20 filled balloon or plastic bag coated withcoupling gel
� Use on irregular shape part
� Place gel on skin, then place the bladder onthe part, and then place gel on bladder
Indications� Soft tissue healing & repair
J i t t t & ti
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� Joint contractures & scar tissue
� Muscle spasm
� Neuroma
� Trigger areas
� Warts� Sympathetic nervous system disorders
� Postacute reduction of myositis ossificans
� Acute inflammatory conditions (pulsed)
� Has been shown to be ok to use following thestopping of bleeding with an acute injury (pulsed)
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Contraindications� Acute conditions (continous output)
I h i i i d i l ti
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� Ischemic areas or impaired circulation areas
� Tendency to hemorrhage
� Around eyes, heart, skull, or genitals
� Over pelvic or lumbar areas in pregnant or
menstruating females� Cancerous tumors
� Spinal cord or large nerve plexus in high doses
� Anesthetic areas
� Stress fracture sites or over fracture site beforehealing is complete (continuous); epiphysis
� Acute infection
Thermal Effects� o blood flow
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� o sensory & motor nerve conduction velocity� o extensibility of structures (collagen);q joint
stiffness
� o collagen deposition
�Mild inflammatoryresponse
� q muscle spasm
� q pain
Nonthermal Effects
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� o cell membrane permeability
� o vascular permeability
� o blood flow
� Synthesis of protein
� q edema� Diffusion of ions
� Tissue regeneration
� Formation of stronger CT
Pulsed Ultrasound
� Stimulates phagocytosis (assists q of chronic
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inflammation)
Clinical Applications Soft Tissue & Plantar
Warts
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� Pitting edema - o temp. makes thick edemaliquefy thus promoting lymphatic drainage
� o fibroblasts = stimulation of collagen
production = gives CT more strength
� Plantar Warts - 0.6 W/cm2 for 7-15 min.
Clinical Applications Scar Tissue, Joint
Contracture, & Pain Reduction
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� o mobility of mature scar
� o tissue extensibility
� Softens scar tissue
� o pain threshold
� o n. conduction velocity
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Clinical Applications
� Chronic Inflammation - Pulsed US has been
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Chronic Inflammation Pulsed US has been
shown to be effective with q pain & o ROM
± 1.0 to 2.0 W/cm2 at 20% duty cycle
� Bone Healing Pulsed US has been shown to
accelerate fracture repair ± 0.5 W/cm2 at 20% duty cycle for 5 min., 4x/wk
Treatment Duration & Area
� Length of time depends on the
Size of area
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± Size of area
± Output intensity
± Goals of treatment
± Frequency
� Area should be no larger than 2-3 times the surface areaof the sound head ERA
� If the area is large, it can divided into smaller treatmentzones
� When vigorous heating is desired, duration should be10-12 min. for 1 MHz & 3-4 min. for 3 MHz
� Generally a 10-14 day treatment period
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Phonophoresis
� US is used to deliver a medication via a safe, painless,
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, p ,
noninvasive technique
� Opens pathways to drive molecules into the tissues
� Not likely to damage or burn skin as with iontophoresis
�
Usually introduces ananti-inflammatory drug
Phonophoresis
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�Factors affecting rate of medication diffusion ± Hydration higher water content = skin more penetrable
± Age better with younger ages
± Composition better near hair follicles, sebaceous glands &sweat ducts
± Thickness thinner skin is better� Types of medications
± Corticosteroids hydrocortisone, dexamethasone
± Anesthetics - lignocaine
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