Understanding Acoustic Emission Testing- Reading 1 Part B-A

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What is AE <strong>Acoustic</strong> emission is the technical term for the noise emitted by materials and structures when they are subjected to stress. Types of stresses can be (1) mechanical, (2) thermal or (3) chemical. This emission is caused by the rapid release of energy within a material due to events such as crack initiation and growth, crack opening and closure, dislocation movement, twinning, and phase transformation in monolithic materials and fiber breakage and fibermatrix debonding in composites. The subsequent extension occurring under an applied stress generates transient elastic waves which propagate through the solid to the surface where they can be detected by one or more sensors. The sensor is a transducer that converts the mechanical wave into an electrical signal (piezoelectric) . In this way information about the existence and location (triangulation by multi-transducers) of possible sources is obtained. <strong>Acoustic</strong> emission may be described as the "sound" emanating from regions of localized deformation within a material. Charlie Chong/ Fion Zhang http://www.geocities.ws/raobpc/AET.html
Until about 1973, acoustic emission technology was primarily employed in the non-destructive testing of such structures as pipelines, heat exchangers, storage tanks, pressure vessels, and coolant circuits of nuclear reactor plants. However, this technique was soon applied to the detection of defects in rotating equipment bearings. Applications: Static subjects Dynamic subjects Charlie Chong/ Fion Zhang http://www.geocities.ws/raobpc/AET.html
Page 1 and 2: Understanding Acoustic Emission Tes
Page 3 and 4: Concrete Offshore structure Charlie
Page 5 and 6: Refinery Applications Charlie Chong
Page 7 and 8: Charlie Chong/ Fion Zhang
Page 9 and 10: The Magical Book of Acoustic Emissi
Page 11 and 12: ASNT Certification Guide NDT Level
Page 13 and 14: 3 Techniques • Equipment calibrat
Page 15 and 16: Fion Zhang at Shanghai 3rd Septembe
Page 17 and 18: Charlie Chong/ Fion Zhang http://gr
Page 19 and 20: Video on - Leak Detection on Buried
Page 21 and 22: ASME V Article Numbers: Gen Article
Page 23 and 24: ASTM Standards E976 - 05 Standard G
Page 25 and 26: ASTM Standards E1781 - 08 Standard
Page 27 and 28: Typical AET Signal https://dspace.l
Page 29: Study Note 1: AET http://www.geocit
Page 33 and 34: Charlie Chong/ Fion Zhang http://ww
Page 35 and 36: AE Technique The AE technique (AET)
Page 37 and 38: What is Normal (Gaussian) distribut
Page 39 and 40: Probability density function for th
Page 41 and 42: Cumulative distribution function of
Page 43 and 44: Crystal Twinning Crystal twinning o
Page 45 and 46: What is Crystal Twinning Crystal tw
Page 47 and 48: Crystal Twinning Charlie Chong/ Fio
Page 49 and 50: Crystal Twinning- Diagram of twinne
Page 51 and 52: AET Set-up Charlie Chong/ Fion Zhan
Page 53 and 54: Continuous type Charlie Chong/ Fion
Page 55 and 56: Discussion Subject: explains on the
Page 57 and 58: Kaiser Effect Plastic deformation i
Page 59 and 60: Felicity effect is an effect in aco
Page 61 and 62: Activity of AE Sources in Structura
Page 63 and 64: Felicity Effect - the applied load
Page 65 and 66: AE Parameters Various parameters us
Page 67 and 68: AET Advantages AE testing is a powe
Page 69 and 70: A Few Typical Applications • Dete
Page 71 and 72: Acoustic Emission Testing Advantage
Page 73 and 74: End of Reading 1 Charlie Chong/ Fio
Page 75 and 76: 16 Acoustic Emission Methods Charli
Page 77 and 78: Charlie Chong/ Fion Zhang
Page 79 and 80: Foreword: Acoustic emission refers
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Acoustic emissions, which occur in
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At about the same time, but indepen
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Figure 1: A cube with sides of leng
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Green also noted the Kaiser effect,
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16.3 Theoretical Considerations Whe
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FIGURE 16.1 The two basic types of
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FIGURE 16.2 A typical acoustic emis
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FIGURE 16.3 Typical view of an acou
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1. The total number of counts (e.g.
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■ Rise time — This is the inter
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Energy analysis — This is an indi
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FIGURE 16.5 The main elements of a
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Fourier-Transform (FT) The Fourier
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Signal Evaluation: Analysis of the
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Signal Evaluation: Raise Time/ Even
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Signal Evaluation: Amplitude Distri
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Signal Evaluation: Energy analysis-
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Signal Evaluation: Raise Time/ Even
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FIGURE 16.5 The main elements of a
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A brief description of the most imp
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PZT:- If the p.d or the stress is c
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AET Transducer In 0.1KHz~2.0KHz Cha
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2. Preamplifier: Because of the low
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There are generally two (or more) c
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Spooner and Dougill confirmed that
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Spooner and Dougill conclusion on K
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16.6.3 Signal Attenuation The elast
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16.6.4 Specimen Geometry It has bee
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16.6.6 Concrete Strength It has bee
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16.7.1 Fracture Mechanics Studies A
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16.7.2 Type of Cracks A number of a
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They found that, while the number o
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Sadowska-Boczar et al. tried to qua
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FIGURE 16.7 Within-batch variabilit
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16.7.6 Fiber Reinforced Cements and
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Fiber Reinforced Cements and Concre
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Perhaps the most extensive series o
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16.7.8 Thermal Cracking Relatively
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They found that acoustic emissions
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Corrosion of Reinforcing Steel in C
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16.8 Field Studies of Acoustic Emis
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16.9 Conclusions From the discussio
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Concrete Structures Charlie Chong/
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Concrete Structures Charlie Chong/
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Concrete Structures- The Troll A pl
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Concrete Structures- The Troll A pl
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End of Reading 2 Charlie Chong/ Fio
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1.0 Introduction Acoustic Emission
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Twinning Charlie Chong/ Fion Zhang
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Acoustic Emission is unlike most ot
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2.0 A Brief History of AE Testing A
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3.0 Theory - AE Sources As mentione
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The amount of energy released by an
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Activity of AE Sources in Structura
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Kaiser/Felicity effects Felicity ef
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Dunegan corollary states that if ac
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Comments: Emissions are observed pr
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Pseudo Sources In addition to the A
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Wave Propagation A primitive wave r
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Waves radiates from the source in a
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Angular dependence of acoustic emis
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The signal that is detected by a se
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highly damped, nonmetallic material
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Attenuation: 1. Spread (30% for 2D,
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Teflon shoe http://www.ndt.net/ndta
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Lamb waves in acoustic emission tes
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2.2.5 Rayleigh Characteristics Rayl
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Q29: The longitudinal wave incident
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The major axis of the ellipse is pe
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Surface wave Charlie Chong/ Fion Zh
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Surface wave has the ability to fol
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Surface wave - One wavelength deep
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Rayleigh Wave Charlie Chong/ Fion Z
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Love Wave Charlie Chong/ Fion Zhang
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Other Reading: Rayleigh Waves Surfa
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Q110: What kind of wave mode travel
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Q192: Surface waves are reduced to
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Since the 1990s, the understanding
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Plate or Lamb waves are the most co
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Plate wave or Lamb wave are formed
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When guided in layers they are refe
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Symmetrical = extensional mode Asym
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Other Reading: Lamb Wave Lamb waves
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Fig. 4 Diagram of the basic pattern
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2.2.7 Dispersive Wave: Wave modes s
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Discussion Subject: Wave Mode and V
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Key Points: • Two classes: resona
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Q. The most common range of acousti
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Equipment- Probe Charlie Chong/ Fio
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Schematic Diagram of a Basic Four-c
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After passing the AE system mainfra
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AET Charlie Chong/ Fion Zhang
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6.0 AE Signal Features With the equ
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Amplitude, A, is the greatest measu
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7.0 Data Display Software-based AE
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Intensity displays are used to give
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Amplitude/counts Signal Analysis Th
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Source location techniques assume t
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Because the above scenario implicit
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When additional sensors are applied
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9.0 AE Barkhausen Techniques The Ba
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Hysterisis Loop- magnetization or d
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■ Bucket Truck (Cherry Pickers) I
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■ Gas Trailer Tubes Acoustic emis
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■ Aerospace Structures Most aeros
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Others • Fiber-reinforced polymer
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Study Note 4: ASTM E1316 Term & Def
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• acoustic emission (AE)- the cla
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• acoustic emission signature (si
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• array, n- a group of two or mor
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• continuous emission- see emissi
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• dB AE - a logarithmic measure o
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AE signal amplitude measured as a r
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• distribution, differential (aco
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effective velocity, n- velocity cal
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FIG. 1 Burst Emission on a Continuo
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FIG. 3 Continuous Emission. (Sweep
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examination area- that portion of a
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Kaiser effect- the absence of detec
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Linear, Planar, 3D Linear 3D Planar
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location, continuous AE signal, n-
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Methods of Location • Hit method
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logarithmic (acoustic emission) amp
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signal overload level- that level a
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stimulation- the application of a s
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End of Reading 4 Charlie Chong/ Fio
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Q1. The most common range of acoust
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Q5. The felicity effect is useful i
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Q9. Threshold settings are determin
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Q12. What is the Felicity Effect? A
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Q15. A Hsu-Nielson Source: A. measu
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Q19. The term ""rise time"" refers
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Q23. Four types of AE Source Locati
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Study Note 6: High Strength Steel-
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The properties of different steels
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Keywords: • DP (dual phase), •
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Figure 1: Ductility-strength relati
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However, with conventional TRIP ste
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Back to Basic: Martensite Martensit
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Keywords: Hexagonal & BCC Martensit
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Figure 2: The stress-strain diagram
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Also, the TRIP steel is particularl
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Figure 3: The diagram shows the ver
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Table 1: Effect of alloying element
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■ B, Ti, Zr Adding small amounts
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Acoustic Emission Technique the opt
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ASM introduction Since 1908, ASM is
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Active approach to leak detection T
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Leak detection and location The mod
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■ Method of testing (Linear) The
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Fig 2: Cross-correlation function p
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The figure 1 shows how the position
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Area surveys using acoustic loggers
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The reading of an area meter could
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CONCLUSIONS In the last fifteen yea
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■ ωσμ∙Ωπ∆ ∇ º≠δ≤
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Charlie Chong/ Fion Zhang
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Peach - 我爱桃子 Charlie Cho
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Good Luck Charlie Chong/ Fion Zhang
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Charlie Chong/ Fion Zhang
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Understanding Acoustic Emission Testing- Reading 1 Part B-A

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