• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1524-1524
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• 2001

A previous paper(Ito et al., 2000) has described the improvement of the standard error(SEC and SEP) of the predicted soluble solids(Brix) in a melon cultivar by non-contact mode with a fiber optic probe. Then we examined the immature and mature fruits. The objective of this study was to determine if non-contact mode could improve the standard error of the predicted Brix of matured melon fruits from cross progeny as well as the contact mode(usual method). The optical absorption spectrum was measured using a NIR Systems model 6500 spectrophotometer. A commercial spectral program(NSAS ver. 3.27) was used for multiple linear regression analysis. Absorbances of 902 and in the vicinity of 877 nm were included as the independent variables in both multiple regression equations. These wavelengths are key wavelengths for non-destructive Brix determination. When the results for the contact mode and non-contact mode are compared, the latter mode improved the former standard error(SEP and RMS).

• Journal of the Korea Institute of Building Construction
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• v.2 no.3
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• pp.123-130
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• 2002

Recently, it is being studied on the high strength concrete in many laboratories and being applied to the construction field actually. But non-destruction testing equation that to be proposed about normal strength concrete in Japan has been using because the systematic study results for the estimation of compressive strength of high strength concrete do nit exist. So it is essential to suggest the non-destruction testing equation for the estimation of compressive strength of high strength concrete. This is an experimental study to analyze and investigate the non-destruction testing equation for the estimation of compressive strength of high strength concrete. The results are as follows; The relation between rebound number, pulse velocity and compressive strength of high strength concrete have lower coefficient than combined method of rebound number and pulse velocity. Also new non-destructive testing equation for the estimation on the compressive strength of high strength concrete was suggested in this study, and it is considered that these equations have possibility to be applied in domestic construction field.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.6
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• pp.427-439
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• 2006

Accurate estimates of in place thickness of early age (3 to 28 days after casting) concrete pavements are needed, where a thickness accuracy of ${\pm}6mm$ is desired. The impact-echo method is a standardized non-destructive technique that has been applied for this task. However, the ability of impact-echo to achieve this precision goal is affected by Vp (measured) and ${\beta}$ (assumed) values that are applied in the computation. A deeper understanding of the effects of these parameters on the accuracy of impact-echo should allow the technique to be improved to meet the desired accuracy goal. In this paper, the results of experimental tests carried out on a range of concrete slabs are reported. Impact-echo thickness estimation errors caused by material property gradients and sensor type are identified. Correction factors to the standard analysis method are proposed to correct the identified errors and to increase the accuracy of the standard method. Results show that improved accuracy can be obtained in the field by applying these recommendations with the standard impact-echo method.

• Smart Structures and Systems
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• v.19 no.5
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• pp.513-521
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• 2017

The purpose of this paper is to study the capabilities of the impulse response method in length and flaw detecting for concrete piles and provide a suggested method to find small-size flaws in piles. In this work, wavelet transform is used to decompose the recorded time domain signal into a series of levels. These levels are narrowband, so the mix of different dominant bandwidths can be avoided. In this study, the impulse response method is used to analyze the signal obtained from the wavelet transform to improve the judgment of the flaw signal so as to detect the flaw location. This study provides a new way of thinking in non-destructive testing detection. The results show that the length of a pile is easy to be detected in the traditional reflection time or frequency domain method. However, the small flaws within pile are difficult to be found using these methods. The proposed approach in this paper is able to greatly improve the results of small-size flaw detection within piles by reducing the effects of any noise and clarifying the signal in the frequency domains.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1580-1583
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• 2005

We report simple new techniques to express analysis of display materials. Colour Cathodoluminescence combined with scanning electron microscopy and spectroscopy is a powerful, non-destructive, high-resolution method for investigation luminescent materials. Some applications of this method to powder phosphors used in display are demonstrated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.255-256
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• 2023

The purpose of this study is to confirm the feasibility of exploring the location of reinforcing bars using the resistivity method in concrete structures.

• Journal of Mechanical Science and Technology
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• v.18 no.8
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• pp.1368-1374
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• 2004

The remaining life estimation for the aged components in power plants as well as chemical plants are very important because mechanical properties of the components are degraded with in-service exposure time in high temperatures. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, nondestructive techniques are needed to evaluate the degradation. In this study, test materials with several different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C$. The DC potential drop method and destructive methods such as tensile and fracture toughness were used in order to evaluate the degradation of 1Cr-1Mo-0.25V steels. In this result, we can see that tensile strength and fracture toughness can be calculated from resistivity and it is possible to evaluate material degradation using DC potential drop method, non-destructive method.

• Journal of Conservation Science
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• v.33 no.1
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• pp.43-49
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• 2017

The ancient paper document we chose as a case study for our research is "One Hundred Poets of the Tang Dynasty", which is housed in the Ryukoku University Library. The purpose of this research is to introduce a method to analyze the surface roughness and microstructure at a high resolution. In addition, we attempt to quantitatively measure the surface unevenness of the types and curve structure. We used a tridimensional digital microscopy as a non-contact and a non-destructive method to study ancient cultural paper. The information contained in the paper may be lost in the process of applying strong pressure to clean and lining or press. However, this microscopic measurement method can non-destructively analyze a large amount of data in old printed books. Moreover, it enables observing them directly with reflected light. Therefore, this method may be useful for collecting printed information remaining on the surface of the paper.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.668-674
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• 2002

Structural integrity assessment is indispensable for preventing catastrophic failure of industrial structures/components/facilities. This diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive and complex procedure of specimen sampling. Especially, the mechanical properties at welded zone including weldment and heat affected zone could not be evaluated individually due to their size requirement problem. So, an advanced indentation technique has been developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. Also indentation technique can evaluate a residual stress based on the concept that indentation load-depth curves were shifted with the direction and the magnitude of residual stress applied to materials. In this study, we characterized the tensile properties and welding residual stress of various industrial facilities through the new techniques, and the results are introduced and discussed.

• Computers and Concrete
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• v.15 no.3
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• pp.473-484
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• 2015

In this study, the availability of Schmidt hammer has been investigated as a reliable method to determine the quality of concrete in irrigation networks. For this purpose, the 28-day compressive strength of concrete material used in the construction irrigation channel of Bafra lowland, which is one of the most fertile plains in Turkey was examined by means of concrete compression and as well as concrete Schmidt hammer in laboratory conditions. This study was carried out on cylindrical samples to represent the everyday concrete party ($150m^3$) produced by contractor firm as 3 replications. The statistical analysis of experimental data showed that the correlations between the values of 28-day compressive strength of Schmidt hammer and the rebound number was found to be 0.98. Differences of the compressive strength between compression testing and Schmidt hammer were statistically significant at P<0.01. In this context, it was found that the reliability of compressive strength of the concrete compression test are excellent, also the reliability of compressive strength of Schmidt hammer are fair in assessing the quality of concrete irrigation channels.