Understanding Infrared Thermography Reading 3

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Imagers (Thermographic Instruments) Imagers (thermographic instruments) consist of both qualitative and quantitative imagers. ■ Qualitative Thermal Imagers Qualitative thermal imagers arc also called thermal viewers. They include mechanically scanned, electronically scanned (pyrovidicon) and staring focal plane array FPA imagers. ● Mechanically Scanned Thermal Viewers Mechanically scanned thermal viewers are moderately priced battery powered scanning instruments that produce a qualitative image of the radiosity over the surface of a targct. The battery packs are rechargeable and usually provide 2 to 3 h of continuous operation. These one-piece, lightweight instruments, designed to be simple to operate, feature thermoelectric detector, cooling provided by a battery powered cooler. Although not designed for absolute temperature measurements, they can demonstrably sense temperature differences of tenths of degrees and can be used for targets from below 0 °C up to 1500 °C (32 of up to 2372 °F). Charlie Chong/ Fion Zhang
Typically, the total field of view is from 6 to 8 degrees high and from 12 to 18 degrees wide, with spatial resolution of 2 mRad 10 mm at 2.0 m (0.4 in. at 7 ft). Images are video recorded by means of a conventional video tape recorder output jack and video recorder accessories. The broad applications for thermal viewers are generally limited only to those in which the temperature measurements are not critical and recording quality does not need to be optimum. The combination of a thermal viewer (to locate thermal anomalies) and a hand held thermometer (to quantify them) can be a powerful and cost effective ombination. Charlie Chong/ Fion Zhang
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Infrared Thermal Testing Reading II
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Infrared Thermography ~-- ... ... .
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Infrared Thermography Charlie Chong
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See Through & Fun Thermal Camera Ex
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How to see through clothing 2 I'
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Apache IR Thermal Weaponry ■ http
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Charlie Chong/ Fion Zhang
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Greek alphabet Letter Name Sound An
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Greek letter l fl 0 I1 p u w Charli
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SGuide-IRT Content Part 1 of 2 ■
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1.1 Introduction to Principles & Th
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The infrared thermal imaging equipm
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The three modes of heat transfer ar
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The three modes of heat transfer ar
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Temperature and Temperature Scales
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Boston Tea Party - New governances
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The Mighty Fahrenheit & ⅝”, Eng
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Absolute zero is equal to - 273.16
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The Fourier conduction Law expresse
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The Fourier conduction Law ( One di
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Convective Heat Transfer Convective
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Figure 1.2: Convective heat flow T
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Newton's cooling law defines the co
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Radiative Heat Transfer Radiative h
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Figure 1.4: Infrared radiation leav
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Thermal infrared radiation impingin
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Reflections off Specular and Diffus
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Reflections off Specular and Diffus
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Radiant Energy Related to Target Su
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The Stefan-Boltzmann law: W= σƐT
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Figure 1.6: Typical blackbody distr
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1.4 Practical Infrared Measurements
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Characteristics of the Target Surfa
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Referring back to Figure 1.5, the t
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Characteristics of the Transmitting
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Figure 1.10; Transmission of 10m (3
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Figure 1.11: Transmission, absorpti
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Figure 1.12: Transmission curves of
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Chapter 1 Review Questions Q&A 1. b
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Q4. Heat can only flow in the direc
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Q10. The follow ing spectral band i
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Q16. In forced convection, the boun
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Q22. In the 8 to 14 μm spectral re
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2.1 Materials Characteristics A kno
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For an emissivity reference table t
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Errors because of point source refl
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View Angle The angle between the in
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Thermal Conductivity Thermal conduc
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Thermal Diffusivity As in emissivit
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Partial 2.1 Table 2.1: d i'ffusivit
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Partial Table 2.2 Table 2.2: Normal
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Chapter 2 Review Questions Q&A 1. c
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4. When measuring the temperature o
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10. A highly textured surface is sa
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3.1 Thermal Instrumentation Overvie
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Thermopile- Thermoelectric Seebeck
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What is a IR Thermopile? (non-conta
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IR Thermopile Quad Sensor (non-cont
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Thermocouple A thermocouple is a te
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Bourdon Gas Thermometers 5 f\G.3 0
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Liquid Crystal Thermometer A liquid
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Bimetallic Thermometers Dial Spiral
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In RTD devices; Copper, Nickel and
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Platinum Resistance Thermometer Cha
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RTD Materials Different materials u
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Operations of RTD An RTD takes a me
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Benefits of Thin Film RTD There are
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Thermistor +V r===~ Op A p V to A I
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3.2 Contacting Thermal Measuring De
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■ Thermocouple Thermocouples are
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■ Thermistors Thermistors arc als
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3.3 Optical Pyrometers Optical pyro
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Pyrometer A pyrometer is a type of
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Brightness Pyrometers -Wien’s Law
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The processing electronics unit amp
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Infrared Detector An infrared detec
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Figure 3.2: Response Curves of Vari
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The mercury cadmium telluride (HgCd
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Infrared Optics - Lenses, Mirrors a
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Field of View (FOV) A field of view
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What is IFOV? A measure of the spat
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Instantaneous Field of View (IFOV)
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3.5 Scanning and Imaging When probl
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Line Scanning When the measurement
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Two-dimensional Scanning - Thermal
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Figure 3.5: Optomechanlcally scanne
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Pyroelectric Vidicon Thermal Imager
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Figure 3.6: Typical uncooled infrar
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IRFPA Charlie Chong/ Fion Zhang htt
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3.6 Performance Parameters of Infra
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Performance parameters of qualitati
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Temperature Range Temperature range
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Temperature Sensitivity Temperature
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Speed of Response Speed of response
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Figure 3.7: Instrument speed to res
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Figure 3.8: Instrument field-of-vie
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D ≡ αd D = spot size (approximat
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Output Requirements Output requirem
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Spectral Range Spectral range denot
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Spectrall y selective instrumems us
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Figure 3.9: Spectral response of an
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3.7 Performance Characteristics of
Page 205 and 206: The total field of view for a line
Page 207 and 208: Instantaneous Field of View IFOV In
Page 209 and 210: Recalling! Temperature sensitivity
Page 211 and 212: IFOV - MTF The 0.35 MTF refers to:
Page 213 and 214: Fig. 2a. Slit Response Function. Ca
Page 215 and 216: Minimum Resolvable Temperature Diff
Page 217 and 218: EXAM score! D=σ∙d IFOV ratio = d
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Page 221 and 222: Answer: D= σ•d, IFOV ration= 1/
Page 223 and 224: Break Time - Kenya Coffee Picker Ch
Page 225 and 226: Portable Handheld Devices Charlie C
Page 227 and 228: Temperature sensitivity and readabi
Page 229 and 230: Hand Held Infrared Module Charlie C
Page 231 and 232: Note that the laser beam docs not r
Page 233 and 234: Emissivity set controls, located in
Page 235 and 236: IR Sensor Module Charlie Chong/ Fio
Page 237 and 238: IR Sensor Module Charlie Chong/ Fio
Page 239 and 240: Two-color Pyrometers or Ratio Pyrom
Page 245 and 246: Phenomena which are non-dynamic in
Page 247 and 248: Some ratio thermometers use more th
Page 249 and 250: Infrared Radiometric Microscopes Ch
Page 251 and 252: Line Scanners Line scanners are div
Page 253 and 254: Special Purpose Devices Special pur
Page 255: FLIR- Forward Looking Infrared Char
Page 259 and 260: Pyroelectric devices have no direct
Page 261 and 262: Figure 3.12: Infrared focal plane a
Page 263 and 264: Infrared focal plane array imager C
Page 265 and 266: Infrared focal plane array imager C
Page 267 and 268: On-board capabilities include isoth
Page 269 and 270: ccc Electron Microscope Image of mi
Page 271 and 272: Platinum Silicide IrFPA 19 t«lU 98
Page 273 and 274: Quantitative IR Image Charlie Chong
Page 275 and 276: Quantitative Thermal Measurements S
Page 277 and 278: In addition to the spot measurement
Page 279 and 280: Stored images can be retrieved, dis
Page 281 and 282: Calibration Accessories Infrared ra
Page 283 and 284: Online printers and plotters are re
Page 285 and 286: Q1. The thermal resolution of an in
Page 287 and 288: Q7. The 3 to 5 μm spectral region
Page 289 and 290: Q13. A line scanner can be used to
Page 291 and 292: Q19. For which of the following app
Page 293 and 294: Q25. Two-color (ratio) pyrometers m
Page 295 and 296: Chapter 4 Operating Equipment and U
Page 297 and 298: ■ Emissivity Differences ∆τ Em
Page 299 and 300: Causes of Real Temperature Changes
Page 301 and 302: Mass Transport Differences (Fluid F
Page 303 and 304: Figure 4.1: An indication of water
Page 305 and 306: Thermal Capacitance Differences ∆
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■ Induced Heating Differences (by
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Induced Heating Differences Charlie
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■ Energy Conversion Differences E
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Figure 4.3: Catalytic reformer vess
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Infrared Thermogram Energy Conversi
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Infrared Thermogram Energy Conversi
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■ Combination of Heat Transfer Me
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Infrared Thermogram of a running mo
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■ Spectral Considerations in Prod
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Infrared Thermogram Charlie Chong/
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Infrared Thermogram ..... " I Charl
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Figure 4.5: Spectral selectivity fo
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Figure 4.7: temperature thermogram
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Figure 4.8 shows the transmission s
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Figure 4.9: Measuring temperature o
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IR Filter Charlie Chong/ Fion Zhang
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Figure 4.10: Line scanner for conti
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Preparation of Equipment for Operat
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If the instrument is out of cal ibr
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The batteries mentioned on the miss
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Comments: ■ ■ ■ Thermal resol
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Figure 4.11 : Test configuration fo
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3. Reduce the ΔT until the image i
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■ Imaging Spatial Resolution Imag
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A sample setup is illustrated in Fi
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5. If the modulation transfer funct
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Figure 4.13: Test configuration for
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4. Open slit until V meas = V max .
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■ Learning the Startup Procedure
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■ Setting the Correct Effective E
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Figure 4.14: Test configuration for
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■ Measuring and Reporting Tempera
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■ Recognizing and Avoiding Reflec
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■ Measuring the Appropriate Backg
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■ Temperature Differences Between
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■ Liquid and Compressed Gases Som
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Dewar Flask for LN Loosely fitting
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■ Electrical Safety Failure to re
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Table 4.1: Electric shock current t
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4.4 Record Keeping Keeping thorough
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Easily accessible and easily unders
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Q1. Apparent but not real temperatu
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Q5. The higher the temperature of a
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Q9. Differential thermography can b
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5.1 Overview of Applications Becaus
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Electrical Applications Electrical
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High electrical resistance is the m
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Excessive heating due to a defectiv
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Inductive currents flowing with in
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Moisture in Airframes The detection
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Process Control and Product Monitor
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The differences produced by this co
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Night Vision, Seareh, Surveillance,
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Thermogram of helicopter taken at n
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Aircraft Under IR Trap Charlie Chon
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Instruments used for these applicat
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8 to 12 μm spectral region over wh
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Animal Studies Body heat allows inf
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Injured equine foreleg (left) appea
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Work energy is expended by friction
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5.4 Fluid Flow Investigations For s
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Figure 1.7: Thermographs of valve (
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■ Building Insulation and Other F
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Figures 5.8 and 5.9 illustrate thes
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Figure 5.9: Example of air exfiltra
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Example of air exfiltration Charlie
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■ Refractory Systems Industrial s
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Refractory Thermogram Charlie Chong
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■ Subsurface Discontinuity Detect
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Figure 5.11: An example of passive
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The equipment necessary to perform
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Figure 5.12: Example of active (hea
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Typical failure modes of the materi
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Figure 5.13: Test of aircraft deici
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DC - 9 Charlie Chong/ Fion Zhang
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Figure 5.14: Conceptual sketch of t
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In this case. however, the heat pul
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Figure 5.15: Erosion/corrosion dama
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737 aircraft Charlie Chong/ Fion Zh
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When there has been adequate solar
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Liquid Level Detection Thermal capa
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Unstimulated and Stimulated Approac
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Subsurface Discontinuity Detection
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1. A major area of infrared nondest
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5. The diagnostics involved in dete
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9. Thermography has been successful
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Appendix A Glossary The following a
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Ambient temperature - Temperature o
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Figure A-1 Apparent ambient tempera
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13.Blackbody, blackbody radiator -
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Alas! Heat Capacity Volumetric = C
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27.Detector, infrared - A transduce
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Thermal Effusivity In Thermodynamic
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Alas! Exitance = Rodiosity for my A
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45.Frame repetition rate - The time
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Thermal Inertia Thermal inertia is
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Instantaneous field of View (lFOV)
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Laser pyrometer - Laser pyrometer -
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Figure 3.2: Response Curves of Vari
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Compare: Minimum resolvable tempera
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86.Radiation rererenee source - A b
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101. Sector - For a line scanner, a
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113. Subtense, angular - The angula
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121. Thermal wave imaging - A term
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125. Thermogram - A thermal map or
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Appendix B Cost Benefit Determinati
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Although the calculations are quite
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96 ASNT Level Ill Study Guide: Infr
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Appendix C, Commonly Used Infrared
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Appendix C, Commonly Used Infrared
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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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