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Midterm - Environmental Engineering > Module 4 - Noise > Flashcards

Module 4 - Noise Flashcards

1
Q

any undesirable or unwanted sound

A

noise

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2
Q

In the ______, the first-generation jet aircrafts led to a rapid expansion in commercial aviation with their ______ creating significant noise which severely disrupted the living patterns in nearby communities.

A

1950s, engines

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3
Q

In the ______, the U.S. Federal Aviation Administration (FAA) introduced the first noise certification standards and the International Civil Aviation Organization (ICAO) promoted similar standards globally (Smith, 1989).

A

1970s

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4
Q

What is Annex 16?

A

Environmental Protection

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5
Q

defined noise standards for aircraft certified before October 6, 1977

A

Annex 16 Chapter 2

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6
Q

defined noise standards for aircraft certified between October 6, 1977 and December 31, 2005

A

Annex 16 Chapter 3

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7
Q

defined noise standards for aircraft certified after December 31, 2005

A

Annex 16 Chapter 4

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8
Q

corresponds to ICAO Chapters 2/3/4

A

US FAR Part 36 Stages 2/3/4

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9
Q

Each new ICAO chapter imposes increasingly stringent noise limits, resulting in a ____ to ____ cumulative reduction in allowable noise.

A

10 to 20-dB

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10
Q

Two General Sources of Aircraft Noise

A

engines, airframe

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11
Q

Aviation Noise Sources

A

turbofan engine noise, turboprop engine noise, airframe noise, engine noise

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12
Q

It comes from the flow of air through and rapid rotations of the various components of the engine fan and core elements, as well as the high-speed gases in the engine exhaust being expelled into the outside air.

A

Turbofan Engine Noise (including APU noise)

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13
Q

This includes the turbulent air shed from each blade and the interactions between the blades.

A

Turboprop (Propeller) Noise

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14
Q

It is caused by the flow of air over the surfaces of the aircraft and the turbulent flows created by the structure and cavities introduced by the deployment of high-lift devices and landing gear.

A

Airframe Noise

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15
Q

It tends to dominate on the ground, especially during takeoff when the engines are at very high thrust level, on landing when using thrust reversers and when taxiing at low speed.

A

Engine Noise

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16
Q

It is created when the aircraft is flying at supersonic speeds which can be very disruptive to activities on the ground.

A

Sonic Boom

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17
Q

This issue severely limited the market for supersonic commercial aircraft introduced in the 1970s.

A

Sonic Boom

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18
Q

Only the ________ found a niche market serving transatlantic routes until its retirement in 2003 on economic grounds.

A

Aerospatiale-BAC Concorde

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19
Q

It is the ratio between the amount of air drawn in by the fan that bypasses the engine core relative to that passing through the core.

A

Bypass Ratio

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20
Q

Bypass ratio of large modem turbofan engines

A

10:1

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21
Q

This configuration achieves a given thrust level with minimum size of core and the slower moving bypass air mixes with the high-speed core air, resulting in a significantly lower exhaust velocity that in turn reduces exhaust noise.

A

large modern turbofan engines

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22
Q

near-term suggested solutions

A

engine core, nacelle chevrons, streamlined landing gear fairings

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23
Q

medium-term suggested solutions

A

geared turbofans, ultrahigh bypass ratio engines (unducted fan)

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24
Q

long-term suggested solutions

A

more integrated airframe/engine designs such as blended-wing body configurations

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25
Q

transmitted from a source through the air in waves

A

sound

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26
Q

It is sensitive to sound pressure.

A

human auditory system

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27
Q

The loudest sound a normal person can hear is approximately ____ times the RMS sound pressure of the faintest sound noticeable.

A

1 million

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28
Q

Its functions are:
- To address the limitations of using unweighted sound pressure levels in assessing the impact of noise on human perception and well-being.
- To provide a more accurate representation of how humans experience noise

A

The A-Weighted Sound Level

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29
Q

defined as a scalar quantity used to indicate the amplitude level of sound at a specific location in space

A

sound pressure

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30
Q

It is the deviation from the ambient atmospheric pressure and is caused by a sound wave

A

sound pressure

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31
Q

depends on the distance the measurement is taken from and in what atmospheric environment it is taken in

A

sound pressure

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32
Q

are not a unit of measure but a logarithmic function which indicates the ratio between two values

A

decibels

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33
Q

when the range of the sound pressure is expressed in decibels it is referred to as ______

A

sound pressure level

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34
Q

refers to the assessment and management of the impact of aircraft noise on the surrounding land uses

A

Aircraft Noise and Land-Use Compatibility

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35
Q

Two types of effects of noise on people

A

behavioural effects, health or physiological effects

36
Q

One of the primary effects of aircraft noise is its tendency to drown out or mask speech, making it difficult or impossible to carry on a normal conversation without interruption. What is this called?

A

Speech Interference

37
Q

Conversations may not require hearing every word; __% intelligibility is often acceptable, but __% is preferred for relaxed conversations.

A

95%, 100%

38
Q

The disruptive effects of noise on sleep

A

sleep interference

39
Q

lead to increased probabilities of sleep disruption

A

higher Sound Exposure Levels (SEL)

40
Q

What does SEL stand for?

A

Sound Exposure Levels

41
Q

What does DNL stand for?

A

Day-Night Average Sound Level

42
Q

refers to the quietest sound that a person could hear

A

threshold shift

43
Q

It is known that excessive exposure to loud noise can temporarily increase a person’s threshold shift but continued exposure to this can cause permanent hearing impairment. What is this called?

A

Noise-Induced Hearing Loss

44
Q

has become the accepted standard for evaluating community noise exposure and helps in decision making regarding the compatibility of alternative land uses

A

Day-Night Average Sound Level (DNL)

45
Q

In FAR Part 150, the FAA has established DNL as the _________ for use in airport noise analyses.

A

official cumulative noise exposure metric

46
Q

All land uses are considered compatible with aircraft day night average sound levels below __ dB

A

65

47
Q

Prediction using computer-based simulation models

A

The Integrated Noise Model (INM), Noisemap

48
Q

offer opportunities for controlling ground-based noise sources such as takeoff and landing roll, taxiway and apron movements, aircraft power-backs. auxiliary power units, and maintenance engine runs

A

noise barriers

49
Q

are walls, earth berms or wall-berm combinations

A

typical barriers

50
Q

For ________, a barrier is often in the form of a pen or series of walls.

A

maintenance runups

51
Q

Along the ______, especially in the vicinity of start takeoff roll, barriers are most effectively placed near the residences they are meant to protect.

A

runway sideline

52
Q

can be degraded by temperature inversions and winds with a component blowing in the direction of source to receiver

A

barrier performance

53
Q

of structures seeks to improve the environment indoors through treatment of the structure itself

A

sound insulation

54
Q

With windows _____ the noise reduction properties of other parts of the structure are largely irrelevant and a noise reduction up to ___ is all that can be expected.

A

open, 14 dB

55
Q

In order to be effective during the summer months, ________ must also be part of a basic noise insulation package so proper ventilation can be achieved with windows closed.

A

central air conditioning

56
Q

Enhancing ________ can provide additional benefit once the aforementioned items are no longer the weak link.

A

roof and wall weight

57
Q

it is based on optimizing runway utilization under wind, weather, demand, and airport layout constraints to minimize population impacts by taking advantage of uneven population distributions around the airport

A

preferential runway concept

58
Q

The FAA has developed a recommended noise abatement takeoff procedure involving power settings and profile characteristics for turbojet-powered aircraft with maximum certificated gross takeoff weights in excess of _____ lb.

A

75,000

59
Q

The objectives of the _________ program are the ensure that jet aircraft noise abatement procedures are safe, standardized and uncomplicated while at the same time being effective at reducing noise levels in the community.

A

National Business Aircraft Association

60
Q

address noise control through reductions in the average noisiness of the aircraft that use the airport

A

noise-based airport use restrictions

61
Q

designed to reduce or eliminate noisy operations during late-night hours when people may be particularly sensitive to noise

A

curfews

62
Q

have been found to be overbroad and to impose undue burden on interstate commerce, and are often viewed as arbitrary and capricious

A

full curfews

63
Q

provide an economic incentive to discourage the operation of noisier aircraft, especially during noise sensitive times of the day

A

noise-based landing fees

64
Q

These are the highest level of regulations and are published in Title 14 of the Code of Federal Regulations (14 CFR).

A

Federal Aviation Regulations (FAR)

65
Q

These are procedures that the FAA staff must follow, and they also apply to airports and airlines when they’re getting approval from the FAA.

A

orders

66
Q

These are documents that provide guidance and information about the FARs and FAA orders. They are not mandatory but can help understand the regulations.

A

Advisory Circulars

67
Q

specific regulation that applies to aircraft noise; sets different noise standards for different types of airplanes; outlines how aircraft noise is measured for certification purposes

A

FAR part 36

68
Q

regulation started in ____ for big jetliners and propeller planes over ____ pounds

A

1969, 12,500

69
Q

defines how airplane noise is measured during the certification process

A

FAR Part 36

70
Q

These were around before the regulation even existed, so they don’t meet any specific noise limits.

A

Stage 1 Aircraft

71
Q

those that met the original noise emission limits established in 1969 but did not meet the revised and more stringent limits introduced in 1977; these aircraft are generally louder than Stage 3 aircraft

A

Stage 2 Aircraft

72
Q

the newest and quietest types; these aircraft must meet the revised noise emission limits introduced in 1977; designed to be significantly quieter than Stage 1 and Stage 2 aircraft, thus minimizing noise pollution

A

Stage 3 Aircraft

73
Q

sets noise limits for airplanes based on their weight

A

FAR Part 36

74
Q

Measured 6,500 meters (about 4 miles) down the runway from where the brakes are released

A

during takeoff

75
Q

Measured 2,000 meters (about 1.2 miles) from the beginning of the runway where planes touch down

A

during approach

76
Q

Measured 450 meters (about 0.3 miles) from the center of the runway, at the point where the plane makes the most noise on the side (usually during takeoff)

A

on the sideline

77
Q

limits noisy airplanes; phased out Stage 1 airplanes; pushed for quieter airplanes

A

FAR Part 91

78
Q

Sets standards for figuring out how loud airplanes are and how that noise impacts people on the ground

A

FAR Part 150

79
Q

2 main parts to a FAR Part 150 plan

A

noise map, noise reduction plan

80
Q

basically a report card on how noisy an airport is and how it affects the surrounding area

A

Noise Exposure Map (NEM)

81
Q

outlines what the airport will do to reduce noise pollution

A

noise reduction plan

82
Q

parts of a noise map

A

airport noise, land use, compatibility issues

83
Q

The second major element of the national noise policy enacted through the Airport Noise and Capacity Act of 1990

A

FAR Part 161

84
Q

It establishes requirements that an airport operator must meet prior to promulgating any airport noise or access restriction on the use of Stage 2 or Stage 3 aircraft

A

FAR Part 161

85
Q

FAR Part 161 stipulates that both types of restrictions may be developed through the FAR Part ___ process.

A

150

86
Q

The benefit of using FAR Part 150 as a mechanism for developing a rule restricting airport access is the _______.

A

availability of federal funding

87
Q

The major disadvantage of submitting Stage 2 restrictions to the FAA as part of the FAR Part 150 submission is that a formal submission will_____ which is otherwise not necessary under FAR Part 161.

A

invoke the approval process

Midterm - Environmental Engineering (3 decks)

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