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[en] This study conducted infrared (IR) thermography tests using pipe and plate specimens with artificial wall-thinning defects to find an optimal condition for IR thermography test on the wall-thinned nuclear piping components. In the experiment halogen lamp was used to heat the specimens. The distance between the specimen and the lamp and the intensity of halogen lamp were regarded as experimental parameter. When the distance was set to 1∼2 m and the lamp intensity was above 60 % of full power, a single scanning of IR thermography detected all artificial wall-thinning defects, whose minimum dimension was 2θ = 90 .deg., d/t=0.5, and L/Do, within the pipe of 500 mm in length. Regardless of the distance between the specimen and the lamp, the image of wall-thinning defect in IR thermography became distinctive as the intensity of halogen lamp increased. The detectability of IR thermography was similar for both plate and pipe specimens, but the optimal test condition for IR thermography depended on the type of specimen
[en] Marangoni-Bénard convection, which is mainly driven by the thermocapillary (Marangoni) effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied experimentally in a 160×160 cavity that is heated from the bottom block. The convection pattern is visualized by an infrared thermography camera. It is shown that the onset of the Bénard cell is consistent with theoretical analysis. The wavenumber decreases obviously with increasing temperature, except for a slight increase near the onset. The wavenumber gradually approaches the minimum when the supercritical number ε is larger than 10. Finally, a formula is devised to describe the wavenumber selection in supercritical convection. (paper)
[en] The paper explains some opportunities and limitations of thermographic investigations in terms of their capability to define the conservative conditions of architectural heritage and in terms of the historical recollection for a technical diagnosis. Different approaches are demonstrated in two case studies: the first integrates thermography with other investigative methods; the second combines thermographic monitoring with hygrothermal monitoring. (author)
[en] Heat transfer from a heated plate to circular air jets issuing from a square array of nozzles is measured by means of an Infrared Scanning Radiometer (IRSR). Experimental tests are performed for different values of jet Reynolds number, nozzle-to-plate distance, nozzle-to-nozzle spacing and nozzle diameter. The two-dimensional character of IRSR and the possibility of processing digital thermal images on a computer allow to obtain surface temperature maps as well as to compute local heat transfer coefficient profiles. (author)
[en] In lock-in thermography, a phase difference between the defect area and the healthy area indicates the qualitative location and size of the defect. To accurately estimate these parameters, the shearing-phase technique has been employed which gives the shearing-phase distribution. The shearing-phase distribution has maximum, minimum, and zero points that help determine quantitatively the size and location of the subsurface defect. In experiment, the proposed technique is verified with artificial specimen and these related factors are analyzed
[en] This paper aims to understand current domestic arts-of-the-states of infrared thermography(IRT) through e-mail survey. This survey is conducted for relevant employers and researchers working in the area of IRT. By thoroughly analyzing some difficulties occurring in on-site fields and application study, it is assumed to be utilized into future research planning. In surveys, usefulness of IR camera, level of utilization, and correction status of IR detector including systems are also considered. for results, 1) analysis in domestic states, 2) satisfaction and problems of technology, and 3) improvement of IRT are described.
[en] The non-destructive testing using infrared thermography is extended to a variety of industries and non-destructive testing of welds using infrared thermography is also in progress in various ways. Currently, a non-destructive testing of electrical resistance spot welds which is mainly used is Radiography Testing. This study detected area of spot welds nugget using optical-infrared thermography. In the results, it is possible for detecting defects of nugget in a short period of time using pulse-infrared thermography.
[en] In the advanced research deducted infrared thermography (IRT) test using 4 inch pipe with artificial wall thinning defect to measure on the wall thinned nuclear pipe components. This study conducted for defect detection condition of nuclear small bore pipe research using deducted condition in the advanced research. Defect process is processed by change for defect length, circumferential direction angle, wall thinning depth. In the used equipment IR camera and two halogen lamps, whose full power capacity is 1 kW, halogen lamps and Target pipe experiment performed to the distance of the changed 1 m, 1.5 m, 2 m. To analysis of the experimental results ensure for the temperature distribution data, by this data measure for defect length. Artificial defect of 4 inch pipe is high reliability in the 2 m, but small bore pipe is in the 1.5 m from defect clearly was detected
[en] In this study, we analyzed and showed the enhanced thermal resolution of a lock-in infrared thermography system by employing a blackbody system and micro-register sample. The noise level or thermal resolution of an infrared camera system is usually expressed by a noise equivalent temperature difference (NETD), which is the mean square of the deviation of the different values measured for one pixel from its mean values obtained in successive measurements. However, for lock-in thermography, a more convenient quantity in the phase-independent temperature modulation amplitude can be acquired. On the basis of results, it was observed that the NETD or thermal resolution of the lock-in thermography system was significantly enhanced, which we consider to have been caused by the averaging and filtering effects of the lock-in technique.
[en] Infrared(IR) thermography method was developed as a result of an investigation into a means of deriving a more visual method of temperature analysis. It recently provides an excellent nondestructive testing(NDT) technique in a variety of industries such as nuclear power plant, fossil plants, etc.. This paper offers a basic principles of infrared radiation, the nature of instruments used for measurement and the applications