Topics in NDE Flashcards by Kayla Silver

One of the major differences in the AE method compared
to most other NDT methods is that:

a. Transducers are used to gather data
b. AE directly detects the growth of flaws
c. Computers are used exclusively for analysis
d. AE relies on visual interpretation of data

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What is the function of comparator in the measurement chain?

a. receive the voltage of the source signal
b. compare the source signal to the threshold voltage
c. generate digital pulse if input signal amplitude exceeds
the threshold voltage
d. all of the above

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Acoustic emissions are generated from:

a. elastic waves generated by the rapid release of energy
from sources within a material
b. Plastic deformation development within a material
c. Dislocation movement, interaction and void displacement
d. All of the above

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The largest voltage peak in the AE signal waveform that is customarily expressed in decibels is:

a. noise
b. event
c. maximum
d. amplitude

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Presence of AE at stress levels below the maximum previously experienced is called _________

a. Felicity effect
b. Kaiser effect
c. Dunegan corellary
d. Primary souce

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The founder of modern acoustic emission technology was:

a. Conrad Earl Krieder
b. Professor Firestone
c. James C. Boiling
d. Josef Kaiser

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What is the property that makes AE testing so different
from traditional NDT methods and is highly desired by
industry?
a. flexibility
b. good trending parameters
c. high sensitivity
d. in-service real time inspection

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The active element inside an AE sensor that senses surface displacements is usually:
a. a strain gauge
b. an inductive coil
c. a piezoelectric crystal
d. a capacitor

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Raising detection threshold (or lowering the gain) to reduce background noise is not desired because it can lead
to:
a. reduced genuine emissions
b. changes in the value of the AE signal features
c. fewer locatable AE events due to fewer detected hits
d. all of the above

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How are AE sensors held in place in the nuclear field?
a. with super-glue
b. with bands and lead blankets
c. with magnets
d. with rolling sensors

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What information should be recorded about background
noise during the test?
a. the magnitude of background noise at periodic intervals
during test
b. the times of any specific noise incidents
c. the effects of noise during examination
d. all of the above

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What type of signals are generated by a crack?
a. continuous
b. burst
c. shock wave
d. noise

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In what acoustic frequency range AE testing usually
works?
a. 10Hz - 100 kHz
b. 20 kHz - 1 MHz
c. 20KHz - 100 KHz
d. 10 kHz - 10 MHz

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The most common artificial source of AE used in industry
is:
a. 0.5mm 2H mechanical pencil lead breaks
b. 0.7mm 2H mechanical pencil lead breaks
c. a spring loaded center punch
d. a handful of small rocks thrown at the vessel wall

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What generates acoustic waves?
a. defect
b. transducer
c. reflection of light rays
d. surface irregularity

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AE sensors may be mounted directly to painted surfaces
if:
a. the paint is oil based
b. the paint is not lead based
c. the paint is smooth, not too thick and well bounded to
the material
d. the paint has been adequately cured

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The loss of amplitude with distance as the wave travels
through the test structure can be explained by:
a. mechanical amplification
b. disturbances
c. signal attenuation
d. thermal conductivity

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How are the acoustic emission probes secured to the
sides of boilers or gear casings?
a. magnets
b. couplant
c. glue
d.AandC

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When an acoustic burst is produced and it is detected by
the sensor what does this indicate?
a. event
b. shaft bowing
c. rubbing
d. peak amplitude distribution

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In order for an AE system to detect an active AE source in
a material, the AE sensor must be placed:
a. at a standard distance from the AE source
b. be anywhere in the general vicinity of the AE source
c. as far as possible from the AE source
d. directly on the AE source

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How can an inspector be assured that proper contact has
been made between the sensor and the vessel?
a. apply extra couplant around the sensor
b. use heavy duty fasteners on sensors and cables
c. measure peak amplitude response from a simulated
acoustic emission source
d. use acoustic waveguides

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What is an advantage of acoustic emission testing?
a. low cost
b. real time inspection
c. high penetration
d. all of the above

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_____is the number of times the AE signal crosses the
detection threshold.
a. counts
b. ringdown counts
c. threshold crossing
d. all of the above

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What can AE not to be used for?
a. defect orientation
b. defect sizing
c. defect propagation
d. defect location

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What did Hsu-Nielsen invent? a. an aid to simulate an acoustic emission event b. an acoustic emission transducer c. a Signal filtering technique d. an acoustic signal pre-amplifier

What is the minimum amount of transducers necessary to identify linear location of a source in a plate? a. two b. four or more c. three d. one

In acoustic emission testing, sensor spacing is mainly governed by: a. sensor diameter b. attenuation c. the test part temperature d. the type of couplant

Which of the following is measured in meters per second (m/s)? a. the resonant frequency of a material b. the velocity of sound in a given material c. the time required for a crack to grow d. the rate of strain when a material is being deformed

What is an important wave mode in AE testing for remote sources? a. pulse propagation b. lamb c. shear d. longitudinal

The AE source signals recognized by __? a. hit-rate b. sensors c. threshold d. monitoring

The process of detection and measurement of an AE signal on achannel is called a a. peak b. signal c. event d. hit

What defects is AE typically used for in the aerospace industry? a. corrosion b. fatigue cracks Cc. aging d. all of the above

Signals produced by causes other than AE, or by AE sources that are not relevant to the purpose of the test are considered as ___ a. hit b. activity c. input d. noise

An opaque surface with an emissivity of 0.04 would be: a. almost perfect reflector b. transparent to IR radiation c. a fairly good emitter d. almost perfect emitter

Which equation can calculate the maximum value of the wavelength on the emittance? Amax= 2100/T Amax= 2898/D Amin= 2898/T Amax= 2898/T

The following spectral band is included in the infrared spectrum: a. 0.1 to 5.5 um b. 0.3 to 10.6un c. 0.4 to 20.0 um d. 0.75 to 100 um

It is not possible to perform the thermographic measurements in the radiation spectrum of: a. 8-10um b.5-7.5um c. 7.5-13.5um d. 2-5um

Which is NOT a property of microbolometer type detector? a. low sensitivity b. broadband response curve c. slow response time d. ability to record transient thermal events

In the 8-14um spectral region: a. IR instruments do not operate very accurately b. the atmosphere absorbs IR radiant energy almost completely c. the atmosphere transmits IR radiant energy very efficiently d. the atmosphere reflects IR radiant energy almost completely

Which of the following are absolute temperature scales? a. Kelvin and Rankin b. Celsius and Fahrenheit

The resulting current of the quantum detector is proportional to the __ of the incident radiation a. intensity b. frequency c. sensitivity d. reflectability

Emissivity of real objects varies with: a. humidity of the air b. ambient temperature c. wavelength d. air pressure

The characteristics of infrared quantum detectors include: a. faster response times than thermal detectors b. arequirement for cooling to operate properly c. selective spectral response based on operating temperature d. all of the above

If a surface has emissivity of 0.35 and reflectivity of 0.45, its transmissivity will be: a. 0.80 b. 0.20 c. 0.70 d. 0.60

What does FPA detector stand for? a. Front Plane Analog detector b. Focal Plane Array Detector c. Flexible Power Analysis Detector d. Focal Point Analysis Detector

An object that has equal emissivity for all the wavelength of radiation is called: a. selective radiator b. blackbody c. greybody d. whitebody

As an object cools, the peak of its spectral emitted radiation: a. remains constant if emissivity remains constant b. shifts to longer wavelength c. shifts to shorter wavelength d. remains constant if emissivity varies

For a opaque greybody target surface, emissivity equals: a. 1.0 b. 1/reflectivity c. reflectivity to the fourth power d. 1-reflectivity

Emissivity of perfect black body is: a. equal to 0 b. from 0-1 c. equal to 1 d. found by experiment by observing intensity of its emissions

An object that has emittance that varies strongly with wavelength is called —__ a. greybody b. selective radiator c. blackbody d. slow radiator

Quantum detector are characterized by: a. high sensitivity b. fast response c. ability to record transient events d. all of the above

Thermal radiation reaching the surface of an object can be: a. transmitted only if the surface is organic b. absorbed only in the presence of atmosphere c. reflected and absorbed only in a vacuum d. absorbed, reflected and transmitted

Which of the following is not an example of an IR advantage? a. Detects a hot spot, temperature differentials and measures these in a non-contact way b. Provides x-ray images so crews can see what's going on inside the equipment enclosure c. Provides visual feedback to maintenance crews for early failure prevention d. Validates the thoroughness and effectiveness of equipment installation

Most instruments used in the infrared thermography operate within the __ spectral region: a. 10-20 unm b. 5-10um c. 2-14 um d. 20-100 um

s an object cools, the peak of its spectral emitted radiation: a. shifts to longer wavelength b. shifts to shorter wavelength c. remains constant if emissivity varies d. remains constant if emissivity remains constant

The cheapest detector utilized in IR cameras is: a. LW photon detector b. SW photon detector c. MW photon detector d. broadband detector

A diffuse reflecting surface is: a. a polished surface that reflects incoming energy ata complementary angle b. also called specular reflecting surface c. usually transparent to IR radiation d. a surface that scatters reflected energy in many directions

What is the Kaiser effect? a. Describes the phenomenon that a material emits acoustic waves under random cycle fatigue b. Describes the phenomenon that a material under load emits acoustic waves only after a primary load level is exceeded c. Describes the phenomenon that a material emits acoustic waves under constant cycle fatigue d. Appearance of significant acoustics emission at a load level below the previous maximum applied level

What goals can be achieved with AE? a. defect location b. defect sizing c. grain boundary condition d. friction coefficient magnitude

The device containing a transducing element that turns AE wave motion into an electrical voltage is called: a. amplifier b. comparator c. sensor d. receiver

What effect appears first when loading a material? a. Crack Propagation b. Kaiser Effect c. Plastic zone growth d. Felicity effect

True or False. An upset customer is usually annoyed with a specific person rather than the organization.

FALSE

True or False. One strategy for preventing dissatisfaction is to think like a customer.

TRUE

When providing a customer service you can positively influence customers by which of the following? a. Providing clients unauthorized bonus services b. Controlling their own thoughts and feelings c. Responding to the client with annoyance d. Responding to the client with anger

True or False. When you cannot meet the demands of an angry customer, you should try to negotiate an alternative solution.

TRUE

True or False. Today's customers are more demanding than in the past.

TRUE

Why is resolving customer service complaints important? a. Customer service complaints that are not handled can Cause a customer to never return and provide negative reviews about the company b. You can receive tax deduction c. Most complaints are coming from lack of knowledge and are not valid, and once you explain customers they are wrong, they will see your point d. It is not important to resolve customer complaint if they cannot find another service provider like your company in the area.

When solving customer service problem you should not: a. Do not let customer speak before you explain to him your point of view b. Ask necessary questions to get complete information c. Find out exactly customer complaint d. Explain first what you can do and then gently what you cannot do for them.

What are the steps to resolve customer's complaint? a. Listen b. Try to understand and sympathize c. Suggest a solution d. All of the above

True or False. Customer expectations do not affect how much service is delivered.

FALSE

True or False. Service breakdowns often occur because customer needs and wants are not met.

TRUE

Friction at the crack surface is usually creating an AE signal that can be classified as __ a. secondary activity b. continuous emission c. burst emission d. A+C

Which of the following can be a significant source of background noise? a. in-rushing fluid b. wind c. radio transmissions d. all of the above

What is a main function of a guard sensor? a. to discriminate from sources originating outside the area of interest b. to localize the position of an acoustic emission source c. to size the defect d. none of the above

Photoelectric effect is the process of __ photons that elevate material's electrons to higher energy state. a. absorbing b. reflecting c. emitting d. transmitting

If athermally opaque object has emissivity of 0.86 what is its reflectivity? a. 0 b. 0.14 c. 1.00 d. 0.86

An object that is a good reflector is also a a. poor emitter b. good emitter c. good absorber d. good emitter and good absorber

Emissivity of a perfect black body is a. found by experiment by observing intensity of its emissions b. equal to 0 c. from 0-1 d. equal to 1

At a temperature of absolute zero: a. Hydrogen becomes liquid b. Salt water is part solid c. Fahrenheit and Celsius readings are the same d. all atomic motion ceases.

Why quantum detectors are cooled to cryogenic temperatures? a. to remove heat absorbed by the detector b. to increase their sensitivity to IR radiation c. to absorb and focus photons of radiation d. to reduce friction of air particles