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45 Cards in this Set
- Front
- Back
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Pressure
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Concentration of force in an area (units = pascals)
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Density
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Concentration of mass in a volume (units = kg/cm3)
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Distance
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Measure of particle motion (units = cm, feet, mile)
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Transverse Waves
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Particles move in a direction that is PERPENDICULAR (at right angles) to the direction that the wave propogates
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Longitudinal Waves
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Particles move in the same direction that the wave propogates
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In-Phase Waves
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When peaks (maximum values) occur and the same time and at the same location
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Out-of-Phase Waves
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When peaks (maximum values) occur at different times and so do their troughs
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Constructive Interference
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Resultant wave is larger than its components
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Destructive Interference
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Resultant wave is smaller than one of its components
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Period
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The time it takes a wave to vibrate a single cycle
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Frequency
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The number of events that occur in a specific duration of time
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Amplitude
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The "bigness" of a wave
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Power
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The rate of energy transfer
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Intensity
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The concentration of energy in a sound beam
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Wavelength
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The distance or length of one complete cycle
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Propogation Speed
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The distance that a sound wave travels through a medium in one second
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Stiffness
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The ability of an object to resist compression
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Density
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The relative weight of a material
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Pulse Duration
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The actual time from the start of a pulse to the end of that pulse
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Spatial Pulse Length
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The distance thta a pulse occupies in space from the start to the end of a pulse
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Pulse Repetition Period
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The time from the start of one pulse to the start of the next pulse.
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Pulse Repetition Frequency
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The number of pulses that an US system transmits into the body each second
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Duty Factor
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The percentage or fraction of time that the system is transmitting a pulse
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Intensities
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Spatial - refers to space
Peak - maximum value Average - middle value Temporal - refers to time Pulsed - transmit time only |
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Beam Uniformity Coefficient
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Describes the spread of a beam in space
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Attenuation
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Weakening of a sound beam in intensity, power and amplitude
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Amplification
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Strengthening of a sound beam
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Decibel Notation
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Standard measurement tool used to report changes in two intensities
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Logarithms
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A novel method of rating numbers, which represents the number of 10's that are multiplied to create the orignal number.
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Reflection
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The portion of a sound beam that is redirected back to the source after striking a boundary
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Specular Reflection
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The sound beam is reflected in only one direction in an organized manner after striking a smooth boundary
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Diffuse Reflection
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The sound beam is reflected in many directions after striking an irregular surface (backscatter)
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Scattering
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The random redirection of sound in many directions
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Raleigh Scattering
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A special form of scattering that occurs when the structure's dimensions are much smaller than the beam wavelength
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Absorption
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US energy is converted into another energy form, such as heat
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Attenuation Coefficient
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The number of decibels of attenuation that occurs when sound travels one centimeter.
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Impedance
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The acoustic resistance to sound traveling in a medium, measured in rayls
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Half-value layer thickness or penetration depth
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The distance sound travels in a tissue that reduces the intensity of sound to one-half its original intensity
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Three Types of Angles
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Acute - less than 90 degrees
Right - equal to 90 degrees Obtuse - greater than 90 degrees |
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Normal Incidence
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The incident sound beam stikes a boundary at exactly 90 degrees
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Oblique Incidence
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The incident beam striks a boundary at any angle other than 90 degrees
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Incident Intensity
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The sound wave's intensity immediately before striking a boundary
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Reflected Intensity
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The sound wave's intensity after striking a boundary that returns back in the direction from which it came
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Transmitted Intensity
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The sound wave's intensity after striking a boundary as it continues forward
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Intensity Reflection Coefficient
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Percentage of the intensity that bounces back after striking a boundary
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