Noise and Vibration Flashcards
Define sound
mechanical radiant energy that is transmitted by pressure waves in an elastic material/medium (such as air) and is the objective cause of hearing
Define noise
sound that is loud, unpleasant or unwanted. However, sound does not have to be loud
What are the three measurable characteristics of noise?
F.I.D
Frequency
Intensity
Duration
Identify the effects of noise on the body
annoyance, fatigue, speech interference, and hearing loss
How does noise cause fatigue?
Fatigue can be caused by a number of physiological responses that have been attributed to noise. Reported responses include effects on blood flow to the skin, respiration, skeletal muscle tension, and constipation
How does an annoying noise affect crewmwmbers while they are performing their duties
Annoying noise can affect pilots while they are performing their duties because it interferes with concentration
TRUE OR FALSE: The denser the substance, the faster and longer the sound will travel
TRUE! The density of the substance determines the speed at which the sound and pressure waves will travel. The denser the substance, the faster and longer the sound will travel
The Surgeon General has establish ____ as the maximum permissible sound level of continuous, unprotected exposure to steady-state noise for _____ hrs
85 decibels, 8 hrs
For every _____ decibel noise increases, exposure time is cut in _____
5, half For every five decibel noise increases, exposure time is cut in half
Types of hearing loss
- Conductive Hearing Loss (impediment in the external or middle ear)
- Sensorineural Hearing Loss (Cochlea is damaged)
Of the two types of hearing loss, which is considered responsive to medical treatment
Conductive Hearing Loss
Of the two types of hearing loss, which is considered permanent and not responsive to medical treatment
Sensorineural Hearing Loss
Since loud noise exposures usually can be predicted, what is the best way to conserve hearing in such hazardous noise environments.
Wear hearing protection in high noise environments to protect hearing.
The HGU-56 and IHADSS helmets protect against aircraft noise on all but two army aircrafts, what are they?
UH60 and CH47
What is vibration
a series of oscillations resulting in the displacement and acceleration of the object (usually the object begins at rest)
the maximum displacement of an object from its position at rest is
Amplitude
the mechanical amplification of vibration by the body occurring at specific frequencies is called
Natural body resonance
A loss of mechanical energy in a vibrating system. causeing the vibration to slow down is know as
Damping
When does the highest level of vibration occur during flight
Hover to flight and flight to hover
What are the short-term effects of vibration on the body
Fatigue, respiratory effects, circulatory effects, motion sickness, disorientation, and pain
How does vibration cause fatigue?
Vibration causes the muscle to contract (exercise) For example, vibration placed on both calves of a standing subject resulted in the subject experiencing the sensation of leaning forward (constant exercise)
The result of vibrating frequencies in the diaphragm will cause
Respiratory effects The result of these “artificial respiration” could lead to hyperventilation if the diaphragm is vibrated at 4-8 hertz
What are the long-term effects of vibration on the body
Raynaud’s disease, Backache/back pain, and kidney/lung damage
TRUE OR FALSE: Backache/back pain in aircrew member may result at an earlier age than normal
TRUE! Backache/back pain in aircrew member may result at an earlier age than normal. The lumbar spineis subjected to higher pressures during aircraft operation because the weight of the torso on that part of the spine while sitting.
what is Raynaud’s Disease?
Raynaud’s Disease (White finger) occurs to the hands after prolonged exposure to vibration from power tools, jackhammers, or other such equipment that vibrates at high frequencies. Trauma occurs in the arterioles and nerve endings in the extremities and limits the blood flow to that portion of the extremity
Identify the effects of vibration on vision during flight
Vision could be affected due to vibration in the aircraft; visual instruments may be difficult to read. Helmet mount or night vision devices may vibrate at 4-12 Hz
At what level is speech distorted from the affects of vibration
Speech can be distorted during oscillations of 4-12 Hz. Above 12 Hz, speech becomes increasingly difficult to interpret
__________ is the mechanical radiant energy that is transmitted by __________ pressure waves.
Sound, longitudinal
Hearing loss can occur due to exposure to noise that is above safe limits and damage may be either?
Temporary or permanent
______ is the maximum displacement of an object from its position of rest.
Amplitude
At how many decibels do humans normally speak?
65 dB
