The biggest jewel beetle in Korea, Chrysochroa coreana, has been nominated as the Natural Monument No. 496 and also classified as Category I of Endangered Species by the Red Data Book. Due to the invisible feature of a saproxylic larval hood inside the host tree for years, the whole life history was hitherto been unknown to the academic world. In order to clarify the period of larval-hood and record images of the process of the final stage of emergence, we obtained sample eggs from two mated couples of adults that emerged from a dead tree of Celtis sinensis on Wando Island, which is well-known as the habitat of C. coreana. Larvae were hatched on four pieces of timber (Celtis aurantiaca) in July 2018 and kept in a growth chamber under the conditions of 25°C, 65% humidity, and in a 12-hour light/dark cycle. The development of larvae was monitored via the non-destructive C/T method every month. Six adults were emerged between February and March 2024. As a result, we obtained the fact that the larval period of C. coreana is minimum 66 months (5.5 years) under lab conditions.

PURPOSES: This study is to estimate nondestructive strength equation based on probability for bridges using field test data. METHODS: In this study, a series of the field inspection and the test have been performed on 297 existing bridges, in order to evaluate the bridges, based on the test results of the in-depth inspection, and the estimated strengths by means of the nondestructive strength equations are analyzed and compared with results of the core specimen strengths. RESULTS: According to results of analyses, In case of standard design compressive strength of concrete is 18MPa, 21MPa, similar reliability of RILEM equation were 0.89~0.90, but in case of standard design compressive strength of concrete is 35MPa, 40MPa were 0.4~0.56. According to standard design compressive strength of concrete is 40MPa, similar reliability of ultrasonic pulse velocity method equation were 0.56. CONCLUSIONS: RILEM equation had high similar reliability than other equation in case of standard design compressive strength of concrete is 18MPa, 21MPa, but had low similar reliability than other equation in case of standard design compressive strength of concrete is 35MPa, 40MPa. and ultrasonic pulse velocity method equation had low similar reliability than other equation in case of standard design compressive strength of concrete is 40MPa.

PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.

Thermographic imaging based non-destructive evaluation proceeds measuring the defect or internal condition of civil structures. To demonstrate the feasibility of the method, the infrared camera system is applied to various specimens. The technique described in this paper may allow us to find their numbers, locations, and the extent of damaged steels from the measurement in the long distance. In addition, a reinforced concrete specimens with different penetration depths is tested using the active thermography method, and to study the influence on the detecting internal rebar in cooled and heated conditions. The experimental results demonstrate that thermographic imaging method is useful for detecting the damage of steel structures and the unknown rebar in the concrete.

The study is conducted in order to establish validity of industrial safety field's neo-qualification composition by suggesting reengineering procedure of NCS based industrial safety field's qualifying occupational plan. The study is conducted in order to establish validity of industrial safety field's neo-qualification composition by suggesting reengineering procedure of NCS based industrial safety field's qualifying occupational plan. NCS based neo-qualification plan is deveopled into progress as following steps; First, planning NCS neo-qualification system. Second, presenting work·education combined program certification standard. Third, developing NCS based neo-qualification assessment standard. Fourth, developing work·education qualification prototype problem. The process of qualification plan was composed with Worksheet 14 and with 4phase being completing summary of each section, certification and development of assessment standard, and development of prototype problem. As a result, Industrial safety manager was redesigned into Industrial sfety manager and Construction Safety Manager, and Occupational Health Care Manager was redesigned into Occupational Health Care Manager and Industrial Health Manager. This study, in conclusion, suggests development of qualifying occupation that could be applied to the integrated management system and development of future industrial safety field's specialized neo-qualifying occupation.

Nondestructive evaluation (NDE) technique method using a resonance frequency by free vibration mode was carried out for damaged and sound black pine woods( Pinus thunbergii ) by Matstucoccus thunbergianae in order to utilize damaged trees. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR in all conditions. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of sound and damaged woods by Matstucoccus thunbergianae.

반사형 테라헤르츠 시스템의 시간 영역 분광을 이용하여 테라헤르츠 time-of-flight 단층 촬영이 시도되었다. 표면이 균일한 샘플일 경우, 동일한 시간 지연에 대한 2차원 평면 단층 영상을 얻을 수 있다. 한 픽셀에서의 최고점의 시간 인덱스로 구성한 2차원 깊이 영상과 다층 구조 팬텀 실험을 통해, 시간 인덱스가 깊이를 나타낼 수 있음을 확인하였다. 집적 회로 칩의 단층 영상을 획득하여 비파괴 검사의 가능성을 보였다. 후처리 과정으로는 STFT(Shot-time Fourier transform)을 이용하였다.

Nondestructive evaluation (NDE) technique method using a resonance frequency by free vibration mode was carried out for heat-treated wood produced under different conditions. The effect of heat treatment on the bending strength and NDE technique using the resonance frequency by free vibration mode of wood for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at 175℃ and 200℃, respectively. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. In all conditions, It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of heat-treated wood under different temperature and species conditions.

원전 부지에 저장중인 방사성폐기물을 처분장에 인도하기 전에 폐기물의 물리·화학적 특성이 인수기준에 적합한지를 검사해야 한다. 검사하는 방법 중 비파괴 검사방법에 대해 조사하였는데, 조사결과 X-ray를 이용한 비파괴 방법을 적용하면 인수검사 항목 중‘드럼내 내용물 검사’,‘ 유리수 및 채움율 정량검사’를 할 수 있는 것으로 나타났다. 본 논문에서는 먼저 X-ray 장비의 원리와 시스템 선정 시 고려해야 할 사항들에 대해 간략하게 살펴 본 후 X-ray 장비를 이용하여 검사해야 할 드럼들의 특성을 분석하였다. 분석한 특성들은 드럼의 종류, 드럼의 규격, 드럼내 내용물의 종류 등이었고 이들 특성자료를 이용하여 검사에 필요한 X-ray 소요에너지를 계산하였다. 계산 결과 드럼 크기가 320 ℓ 이하인 드럼을 검사하기 위한 소요에너지는 3 MeV 이하로 나타났으며 경제성 및 실현가능성 측면에서 450 keV 장비와 3 MeV 장비를 조합하거나 단독으로 사용하는 것이 바람직하고 이 때 450 keV 장비를 이용하여 검사가 가능한 저밀도 드럼수는 2006년 12월 저장기준으로 42,327 드럼, 3 MeV 장비를 이용하여 검사가 가능한 드럼 수는 18,105 드럼으로 나타났다. 검사를 수행하는 주체, 장비 구매 방안 등에 따라 4가지 검사 시나리오를 수립하고 이에 대해 경제성 및 적용 가능성을 분석한 결과 최적의 검사시나리오는 인수기준, 처리 및 처분장 인도에 대한 폐기물 발생자의 정책 등에 영향을 받는 것으로 나타났다. 예를들어,‘ 유리수’,‘ 채움율’에 대한 정량분석과‘내용물 확인’을 모두 해야 할 경우에는 밀도가 상대적으로 낮은 폐기물이 담겨있는‘저밀도 드럼’의 검사를 위해 450 keV 이동형 장비 2대를 구입하여 자체 검사하고‘고밀도 드럼’은 외주로 검사하는 것이 바람직할 수 있다. 반면‘내용물 확인’만을 비파괴 검사항목으로 할 경우에는 450 keV 급 이동형 장비 1대면 연간 13,000 드럼을 검사할 수 있는 것으로 나타났다.

본 연구에서는 경계 요소법을 이용하여 2차원 비등방성 탄성체의 손상 규명을 수행한다. 경계에서의 적분항만을 포함하는 본 수치모델은 1차원으로 줄게된다. 이러한 장점은 특히 균열 역학과 같은 문제에 있어서 중요한 의미를 갖는다. 또한 일정 영역을 분할하는 기법을 피함으로서 수치해석 과정을 간편하고 효율적으로 수행할수 있기 때문에 역문제 해결에 있어서 장점을 갖는다. 본 연구에서는 기존의 등방성 재료에 대한 비파괴 추정기법을 복합신소재와 같은 비등방성 재료로 이루어진 탄성체의 해석에 대하여 확장한다. 먼저 경계요소법에 의한 수치모델의 타당성을 기존의 문헌과 비교 검증하며, 서로 다른 특성을 보이는 비등방성 형식의 변화에 따라 실제 측정시 발생하는 노이즈 영향을 분석한다. 수치예제는 적층 형태 및 하중조건에 대하여 수행하며, 결함 추정에 미치는 적층 형태의 영향을 시험한다.

본 논문에서는 시간영역에서의 응답을 이용하여 복잡한 트러스의 구조물에서 발생할 수 있는 손상의 위치와 크기를 추정할 수 있는 알고리즘을 제안하였다. 일정한 시간동안 획득한 응답데이터를 각 부재별 평균 변형에너지를 구하기 위하여 공간적으로 확장하였다. 이렇게 확장된 평균 변형에너지는 다시 손상 지표를 구축하는데 사용하였으며, 손상 지표는 손상 전과 손상 후의 구조물의 강성의 비이다. 본 논문에서 제안한 방법론의 타당성은 유한요소 모델로 손상을 모의하고 이로부터 얻은 응답데이터를 적용하여 입증하였다. 또한 응답데이터에 노이즈를 추가하여 노이즈가 제안한 알고리즘에 미치는 영향도 분석하였다.

PSC 보의 비파괴 손상검색을 위한 고유진동수 이용 손상추정법과 모드형상 이용 손상추정법을 제시하였다. 먼저, 고유진동수의 변화를 사용하여 손상의 위치를 예측하는 알고리즘과 고유진동수 1차 섭동 이론에 근거하여 균열크기를 예측하는 알고리즘을 요약하였다 다음으로, 모드형상의 변화로부터 모드민감도의 변화를 감지하고 이를 통해 손상의 위치와 크기를 추정하는 손상지수 알고리즘을 요약하였다. PSC 보의 유한요소모델을 사용하는 수치실험을 통해 고유 진동수 이용 손상추정법과 모드형상 이용 손상추정 법의 정확성을 검증하였다. 분석결과 두 방법 모두 실험 대상 구조에 도입된 균열의 위치를 정확하게 예측하였으며 균열의 크기를 비교적 근사하게 예측하였다.