• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.197-204
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• 2021

In this study, the well-known non-destructive acoustic emission (AE) and electrical resistivity methods were employed to predict quantitative damage in the silo structure of the Wolsong Low and Intermediate Level Radioactive Waste Disposal Center (WLDC), Gyeongju, South Korea. Brazilian tensile test was conducted with a fully saturated specimen with a composition identical to that of the WLDC silo concrete. Bi-axial strain gauges, AE sensors, and electrodes were attached to the surface of the specimen to monitor changes. Both the AE hit and electrical resistance values helped in the anticipation of imminent specimen failure, which was further confirmed using a strain gauge. The quantitative damage (or damage variable) was defined according to the AE hits and electrical resistance and analyzed with stress ratio variations. Approximately 75% of the damage occurred when the stress ratio exceeded 0.5. Quantitative damage from AE hits and electrical resistance showed a good correlation (R = 0.988, RMSE = 0.044). This implies that AE and electrical resistivity can be complementarily used for damage assessment of the structure. In future, damage to dry and heated specimens will be examined using AE hits and electrical resistance, and the results will be compared with those from this study.

• Journal of Industrial Technology
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• v.43 no.1
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• pp.7-13
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• 2023

Nowadays, traffic congestion is emerging as a major problem due to the rapid population growth and the increase in automobiles. The train is a convenient means of transportation that can efficiently solve these problems. Trains have been developed in line with human aspirations for a long time, but research on safety is still insufficient. This study aims to check safety by conducting static tests and fatigue tests on bogie frames, and to help develop bogie frames in the future. For the static test, a strain gauge was attached to the point where the local stress concentration was expected beforehand, and the result value was derived, compared with existing theories, and expressed as a Goodman diagram. In the fatigue test, a total of 10 million loads were applied over three stages, and no cracks appeared in the non-destructive test conducted after each stage. Both tests were conducted according to the strict test method of the bogie frame presented by the UIC Code. It satisfied both fatigue life and strength evaluation criteria and was judged to be a bogie frame usable for safe train production.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6553-6558
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• 2014

Background: This study was conducted to gauge how the demographic profile of smokeless tobacco (SLT) users from Gujarat and Andhra Pradesh, India, differs from that of smokers. It also addresses how factors associated with the initiation and continuation of smokeless tobacco vary by age, gender, and education. Materials and Methods: We analyzed 2011 cross-sectional survey data collected from 4,759 respondents (smokers/SLT users/non-users) in both states. Chi-square analysis was used to make comparisons between the demographic profiles of smokers and SLT users. Multivariable logistic regression analysis was used to obtain the odds ratios (ORs) for initiation and continuation factors regressed on socio-demographic variables (age, gender, education). Results: Initiation-women were less likely than men to report "peer pressure", "fashion statement", and "stress/coping" as relevant factors for SLT use (OR: 0.45 CI: 0.30-0.70; OR: 0.42 CI: 0.24-0.74; OR: 2.47, CI: 1.47-4.15). Older age groups had lower odds of choosing "peer pressure" than the 15-24 year olds. Respondents with 11 or more years of education were more likely to report "stress/coping" than those with no education (OR: 2.82, CI: 1.06-7.48). Continuation-women were less likely than men to choose "relaxation", and "distance from family" as important continuation factors (OR: 0.50, CI:0.32-0.80; OR: 0.20, CI: 0.06-0.65). All age groups were less likely to choose "stimulation" as a factor than the youngest group. Conclusions: Along with confirming and expanding upon previous literature, the findings of this study should encourage further SLT research in women and younger age groups (15-24 and 24-44). They also confirm the need for SLT prevention and cessation interventions in India in other community-based settings, besides schools.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.11-20
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• 2007

This thesis develops a fatigue model for the asphalt black base using the APT(Accelerated Pavement Testing) and analyzes the correlation of the APT analysis result with results of previous laboratory tests. For the APT testing, aggregate of the maximum grain size of 25mm(BB-3) was used as the material for the asphalt black base. The result of the APT revealed that the variable of the fatigue model, i.e. the maximum tensile stress on the bottom part of the pavement, increased as the number of loading increased while the modulus of elasticity for the pavement layer decreased gradually. The tensile strain was obtained from a strain gauge, and it was used to derive the values of $k_1=1.29{\times}10^{-6}$ and $k_2=3.02$ from the basic equation of the asphalt fatigue model, $N_f=k_1(\frac{1}{\epsilon})^{k_2}$. The fatigue life predicted from the asphalt fatigue model was greater than that obtained from laboratory experiments, given the same tensile strain. Additionally, a theory to estimate the remaining life of the pavement was developed using FWD, a non-destructive experiment.