• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.555-561
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• 2000

The remote field eddy current (RFEC) inspection was performed on the ductile cast iron pipes with nominal outer diameter of 100mm, which were machined with various shapes and sizes of defects. Ductile cast iron pipes which are used as water supply pipe have the non-uniform thickness and asymmetric cross section due to relatively high degree of allowable errors during the manufacturing processes. These characteristics of ductile cast in pipes cause the long range background noises in RFEC signals along the pipe. In this study, tile machined defects in pipes were effectively classified by the moving window average (MWA) method which eliminated the long-range noise. The voltage plane polar plots (VPPP) method was used to quantitatively evaluate the depth and circumferential degree of defects. The VPPP signatures showed that the angle between defect signature and the normalized in-phase component on the VPPP is linear to the depth of defects. The nondestructive RFEC technique proved to be capable of quantitatively evaluating the machined defects of underground water supply pipe.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.12-19
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• 2012

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 $2{\Theta}=90^{\circ}$, d/t=0.5, and $L/D_o=0.25$, 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.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.352-363
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• 2021

This study aimed to examine the different factors affecting the intention to purchase meal kits between at-home concept meal kits and eating-out concept meal kits. An online survey was conducted with 565 Korean participants including meal kit experienced (n=412) and non-experienced (n=153). Meal kits selection attributes were organized into five factors, health, price, environmental protection, convenience, and familiarity. To verify the hypothesis, SPSS Statistics 23 was used. The main results can be summarized as follows. First, in the case of the at-home menu, convenience(p < .01), environmental protection(p < .05), and familiarity(p < .01) show positive influences on willingness to buy. Second, for the eating-out menu, health(p < .001) and convenience(p < .001) have positive effects on willingness to buy, but familiarity(p<.01) has a negative effect. This is the first study to categorize the menu of meal kits and investigate each factor affecting willingness to buy. Therefore, the results can offer useful guidelines to meal kit marketers letting them know the consumers' purchase behaviors.