• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.139-143
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• 2003

Mathematical constants for multiplication with leaf length (I) or breadth (b) or l ${\times}$ b have been worked out for determining leaf area in promising mulberry genotypes viz., Chinese White, S-146, Chak Majra and Sujanpur Local of sub-tropical India. When pooled, the mathematical constants worked out were 8.1132, 10.1019 and 0.5992 for multiplication with leaf length, breadth and l ${\times}$ b, respectively, for genotypes bearing un-lobbed leaves and 6.9447, 8.2761 and 0.5009 for multiplication with leaf length, breadth and l ${\times}$ b, respectively for genotypes bearing lobbed leaves. Leaf area can be worked out by using any constant by multiplying either with leaf length or breadth or both (l ${\times}$ b). Estimated leaf areas worked out were found significantly and positively correlated with actual leaf area (r＝999$^{＊＊}$). The suggested present non-destructive method by using mathematical constants is very quick and alternative to electronic leaf area meter for spot leaf area determination in mulberry which is the only food source for mulberry silkworm in sericulture industry.

• 터널과지하공간
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• 제14권1호
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• pp.35-42
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• 2004

충격반향기법은 콘크리트 구조물 내부의 결함과 외부 표면 사이에서 반사되어 전락되는 충격생성응력파를 이용한 비파괴적 시험 방법이다. 본 연구에서, 토목 및 건축 구조물의 안전진단을 위하여 충격반향기법을 이용한 비파괴 시험을 수행하였다. 야외 시험 조건은, 터널라이닝 모델에 대한 주파수 영역에서, 모델의 두께 변화를 측정할 수 있는 경우와 모델 내 공동이 있는 경우의 공동의 위치를 파악하는 경우, 그리고 터널라이닝 조건에서의 라이닝 두께 및 공동위치를 파악하는 경우를 시험하였다.

• Food Science and Biotechnology
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• 제18권1호
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• pp.60-65
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• 2009

Near infrared reflectance spectroscopy (NIRS) was used as a rapid and non-destructive method to determine the protein content in intact and ground seeds of pea (Pisum sativum L.) germplasms grown in Korea. A total of 115 samples were scanned in the reflectance mode of a scanning monochromator at intact seed and flour condition, and the reference values for the protein content was measured by auto-Kjeldahl system. In the developed ground and intact NIRS equations for analysis of protein, the most accurate equation were obtained at 2, 8, 6, 1 math treatment conditions with standard normal variate and detrend scatter correction method and entire spectrum (400-2,500 nm) by using modified partial least squares regression (n=78). External validation (n=34) of these NIRS equations showed significant correlation between reference values and NIRS estimated values based on the standard error of prediction (SEP), $R^2$, and the ratio of standard deviation of reference data to SEP. Therefore, these ground and intact NIRS equations can be applicable and reliable for determination of protein content in pea seeds, and non-destructive NIRS method could be used as a mass analysis technique for selection of high protein pea in breeding program and for quality control in food industry.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.207-208
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• 2021

The non-destructive method using ultrasonic waves has been applied in many studies due to its low damage to the structure and its simple evaluation method and high precision. On the other hand, if the concrete is subjected to a high-temperature, the mechanical properties may be deteriorated due to the micro-crack network and the damage may be severe depending on the strength of the concrete. Therefore, this study attempts to evaluate the fundamental wave behavior of different strength ranges using the ultrasonic non-destructive method for concrete that has been subjected to high-temperature. As a result, the relative power of the fundamental wave was decreased as temperature increase. And it was confirmed that the 2nd and 3rd harmonics were generated at 110 MPa. However, to check the 2nd, 3rd harmonics 110 MPa or less, there is a need for further research considering the ultrasonic output, the output of the sender and receiver, and the appropriate frequency accordingly.

• 한국구조물진단유지관리공학회 논문집
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• 제12권6호
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• pp.173-179
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• 2008

비파괴시험에 의한 콘크리트 압축강도 추정시 반발경도법은 콘크리트 타설 후 시간경과에 따라 재령계수를 적용하고 있으나 초음파속도법은 적용되지 않고 있다. 재령경과에 따른 콘크리트 초음파속도의 변화에 대한 재령계수 적용의 필요성에 대하여 검토해야함에도 불구하고 그에 대한 연구가 거의 없는 실정이다. 따라서 본 연구는 콘크리트 초음파속도를 측정하여 강도 추정식에 적용될 재령계수를 산정하기 위한 실험을 실시한 결과, 초음파속도는 콘크리트 경화에 따라 재령 초기 기준치에 비교하면 급격한 변화를 보여 재령계수를 반드시 적용해야 한다는 것을 알 수 있었으며 실험결과에 의해 콘크리트 초음파속도의 재령계수를 제안하였다.

• 콘크리트학회논문집
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• 제15권3호
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• pp.425-432
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• 2003

콘크리트 시공 이음부는 콘크리트 시공시 발생되는 기술적 문제들 중의 하나이다. 이 시공 이음부는 콘크리트의 구조적 측면뿐만 아니라 누수 등의 중대한 결함을 초래하게 되는 요인으로 작용한다. 본 연구에서는 이러한 콘크리트 구조물의 시공 이음부를 비파괴적으로 검사하기 위해 레이더법과 적외선법을 이용하였다. 대상부재로서는 콘크리트 기둥을 선정하여 본 방법들의 적용에 따른 여러 가지 형태의 시공 이음부의 검출특성에 대하여 검토하였다. 그 결과, 레이더법의 경우는 해석모델에 의한 모의해석을 실시하여 실제 측정치와 비교하여 해석할 경우, 시공 이음부에 대한 검출 정도를 보다 향상시킬 수 있음을 알 수 있었다. 또한, 적외선법의 경우는 빛의 작용을 받지 못하는 실내조건 하에서도 측정 표면부를 사전 가열하여 측정하면 결함의 형상까지도 뚜렷이 식별하여 검출 가능함을 알 수 있었다. 따라서, 이들 두 방법을 병행할 경우, 육안으로는 검사가 곤란한 콘크리트 시공 이음부에 대해 빠른 시간내에 넓은 대상의 구조물에 대해 효율적인 검사가 가능함이 입증되었다.

• 콘크리트학회논문집
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• 제19권1호
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• pp.75-81
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• 2007

콘크리트는 전체 체적의 $70{\sim}80%$가 골재로 이루어져 있다. 따라서 골재의 품질은 콘크리트 특성에 지대한 영향을 미친다. 현재 건설 현장에서는 부순모래 콘크리트의 비파괴 강도 추정을 일반적으로 슈미트해머를 이용한 반발 경도법이나 초음파를 이용한 초음파속도법 그리고 둘을 조합한 복합법을 이용하고 있으며 기존의 천연골재를 사용한 콘크리트에 의해 얻어진 여러 가지 제안식들에 적용시켜 추정하고 있다. 따라서 본 연구의 목적은 전형적인 파괴 시험과 코어 채취 그리고 반발경도법과 초음파속도법을 이용하여 부순모래 콘크리트의 강도 추정식을 제안하고자 하였다. 실험의 변수는 양생 재령과 양생 조건 그리고 콘크리트의 설계기준강도이다. 그 결과 본 연구에서 얻은 제안식이 기존식에 비해 모든 측면에서 양호한 것으로 나타나 실제 건설 현장의 부순모래 콘크리트 구조물의 평가 기술 향상에 기여할 것으로 사려 된다.

• 한국산업보건학회지
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• 제11권3호
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• pp.229-234
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• 2001

The EDXRF(Energy Dispersive X-ray Fluorescence Spectrometer) technique was applied to the determination of heavy metals in welding fume. The EDXRF method designed in this study was a non-destructive analysis method. Samples were analyzed directly by EDXRF without any pre-treatment such as digestion and dilution. The samples used to evaluate this method were laboratory samples exposed in a chamber connected with a welding fume generator. The samples were first analyzed using a non-destructive EDXRF method. The samples subsequently were analyzed using AAS method to verify accuray of the EDXRF method. The purpose of this study was to evaluate the possibility of the non-destructive analysis of heavy metals in welding fume by EDXRF. The results of this study were as follow: 1.When the samples were collected under the open-face sampling condition, a surface distribution of welding fume particles on sample filters was uniform, which made non-destructive analysis possible. 2. The method was statistically evaluated according to the NIOSH(National Institute for Occupational Safety and Health) and HSE(Health and Safety Executive) method. 3. The overall precision of the EDXRF method Was calculated at 3.45 % for Cr, 2.57 % for Fe and 3.78 % for Mn as relative standard deviation(RSD), respectively. The limits of detection were calculated at $0.46{\mu}g$/sample for Cr, $0.20{\mu}g$/sample for Fe and $1.14{\mu}g$/sample for Mn, respectively. 4. A comparison between the results of Cr, Fe, Mn analyzed by EDXRF and AAS was made in order to assess the accuracy of EDXRF method. The correlation coefficient between the results of EDXRF and AAS was 0.9985 for Cr, 0.9995 for Fe and 0.9982 for Mn, respectively. The overall uncertainty was determined to be ${\pm}12.31%$, 8.64 % and 11.91 % for Cr, Fe and Mn, respectively. In conclusion, this study showed that Cr, Fe, Mn in welding fume were successfully analyzed by the EDXRF without any sample pre-treatment such as digestion and dilution and a good correlation between the results of EDXRF and AAS was obtained. It was thus possible to use the EDXRF technique as an analysis method of working environment samples. The EDXRF method was an efficient method in a non-destructive analysis of heavy metals in welding fume.

• 콘크리트학회논문집
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• 제11권4호
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• pp.157-167
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• 1999

Among several non-destructive testing methods, ultrasonic pulse velocity method and rebound index method have been widely used for the evaluation of concrete strength. However, such methods might not provide accurate estimated results since factors influencing the relationship between strength and either ultrasonic pulse velocity or rebound index are not considered. In this paper, the evaluation method of concrete strength using rod-wave velocity measured by impact-resonance method is proposed. A basic equation is obtained by the linear regression of velocity vs, strength data at specific age and then, aging factor is employed in the equation to consider the difference of the increasing rate between wave velocity and strength. Strengths predicted by the proposed equation agree well with test results. Furthermore, the combined method of rod-wave velocity and rebound index is proposed.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.856-862
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• 2020

Defect inspection system for industrial applications takes the important portion. Non-destructive inspection method has been significantly improved. Infrared thermography, as one of method for non-destructive inspection, can provide relatively precise data and quick inspection time. This study, it was performed to measure defect according to the measurement limit of the non-visible areas such as the back surface of the pipe using reflection plate using reflection plate based on Infrared thermography. The materials of the reflection plate were determined in consideration of the space limitation and the thermal characteristics, and defects were detected by the manufactured reflection plate. Detection of defect in non-visible area using the candidate materials for reflection plate was conducted.