• 한국지반환경공학회 논문집
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• 제2권4호
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• pp.5-14
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• 2001

최근 구조물기초에 큰 변형 및 손상을 가하지 않고 안정성에 대한 정보를 비교적 쉽게 얻을 수 있는 비파괴시험(NDT, Non-Destructive Testing)기법이 큰 관심을 얻고 있다. 본 연구에서는 비파괴시험 중 검측공 기법(CSL, CT, PS)과 표면파 기법(SE, IR)을 현장타설말뚝의 건전도 평가에 이용하기 위한 적용성의 문제를 현장시험을 통하여 고찰하였다. 이를 위하여 결함이 없는 한 본의 정상말뚝과 연약선단, 단면축소 확대, 불량콘크리트 타설 등 현장에서 발생하기 쉬운 결함의 종류, 크기, 위치 등을 변화 조합한 9본의 현장타설말뚝(직경 0.4m, 길이 7.0m)을 시공하여 다양한 비파괴시험을 수행하였다. 시험을 통하여 각 기법을 현장타설말뚝의 건전도 평가에 적용할 때의 문제점과 각 기법의 합리적인 조합에 대하여 고찰하였다.

• Journal of Welding and Joining
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• 제14권5호
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• pp.122-133
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• 1996

In order to evaluate the cryogenic fracture characteristics of structural steels for superconducting magnets of fusion reactor, small punch (SP) testing was performed on austenitic stainless steel (JN1 base metal) and its TIG weldments at 293K, 77K and 4K. The mechanical properties with respect to the extracted location of the weld metal, on the effects of welding heat cycle about base metal near fusion line in TIG weldments were investigated. The mechanical property of the weld metal in TIG weldments depends on distance from welding root, root region of weldments having the lowest mechanical property. The base metal near fusion line showed degradation of mechanical property caused by cyclic heating during the TIG welding. Based on the test results, HAZ was found to be up to 5mm from the fusion line. It is shown that SP testing is a useful tool to evaluate the mechanical properties with respect to the microstructures changes such as HAZ as well as weld metal in TIG weldments at cryogenic temperature.

• Tribology and Lubricants
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• 제33권1호
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• pp.31-35
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• 2017

Recently, international attention has been focused on the development of non-traditional energy resources such as shale gas and oil sands, due to the steep increase in the demand for natural resources. The materials incorporated in an oil gas plant module experience extreme environments, and are prone to various problem such as fracture, corrosion and abrasion due to low-temperature brittleness. In order to improve the plant life, it is necessary to perform characteristics study and performance evaluation of the materials. In particular, this paper explains the main set of materials which are most frequently used in oil sands plant project. In order to investigate wear characteristics, the authors carried out abrasive wear tests of TP 316, stainless steel and SS 400, structural rolled steel. For the analysis of the abrasive wear resistance of an oil sands plant, the authors carried out the test according to ASTM G 105 "Standard Test Method for Conducting Wet Sand/Rubber Wheel Abrasion Test" standard guidelines. The authors have derived the results from the data associated with the loss of mass with respect to wear rate. During the test, for a given wear length for 10,000 revolutions, the rotational speed and applied force of the rubber wheel were varied.

• 비파괴검사학회지
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• 제20권1호
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• pp.18-26
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• 2000

화력발전소 보일러 고온배관인 주증기관, 헤드 및 증기드럼 등의 설비들은 장시간동안 고온고압의 가혹한 조건으로 운전됨에 따라 크리프손상에 의해 열화되고 있다. 이들 설비의 크리프손상측정에 적용되는 종래의 비파괴기법인 레프리카법, 전기저항법 및 경도법 등은 복잡한 측정절차 및 접근성, 검사결과의 신뢰도 및 측정정도 등 여러가지면에서 단점이 많다. 따라서 본 논문에서는 화력발전소 주요 고온배관에서 발생되는 경년열화인 크리프손상에 대한초음파 측정연구를 수행한 결과로서, 고온배관재료인 Cr-Mo강의 크리프 인공열화재를 대상으로 이들에 대한 크리프손상 상태별 초음과 음속(sound velocity) 및 감쇠(attenuation)의 초음파 신호특성을 평가하였다.

• 한국전산구조공학회논문집
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• 제21권5호
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• pp.465-474
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• 2008

실시간 하이브리드 실험법(real-time hybrid testing method)은 구조물의 수치해석부와 실험부 부분구조를 운동방정식으로 통합하여 실시 간으로 동시에 계산과 실험을 수행하는 방법이다 본 연구는 실시간 하이브리드 실험법을 사용하여 수동 및 준능동 MR감쇠기가 설치된 건축구조물의 내진성능을 정량적으로 평가한다. 건물 모델은 실물 크기 5층 건물을 강제진동실험 결과를 통해 식별한 수치모델로 사용하였고, MR감쇠기는 실험적 부분구조르 UTM에 설치되었다. 본 연구에서 수행되는 실시간 하이브리드 실험은 사인파 및 지진파 가진을 통하여 얻은 결과와 전류에 따른 MR감쇠기의 제어력을 이용하여 얻은 Bouc-Wen모델을 사용하여 얻은 해석모델과 일치함으로 그 유효성을 입증하였다. 또한 예비연구로써 구조물의 응답을 최적으로 제어하기 위한 clipped-optimal 제어알고리즘과 modulated homogeneous friction 준능동 제어알고리즘을 MR감쇠기에 적용하였다. 각 전류별 Bouc-Wen모델을 곡선맞춤하여 각각의 Bouc-Wen모델 파라미터를 식별하였으며 그 결과를 준능동 제어알고리즘 수치해석에 적용하였다. 또한 실시간 하이브리드 실험법을 이용한 준능동 제어 실험결과와 해석결과를 비교하여 준능동 제어알고리즘의 성능을 평가함에 있어 실시간 하이브리드 실험이 합리적임을 보여준다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권2호
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• pp.129-136
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• 2014

Reliability test is focusing to detect the unexpected reliability failure and solve them for the high quality of products. The test data should be used to assess and project the current level of interesting product reliability and so it is very important to have the accurately assessing methodology with test data. There are two type of trend for test data as constant and changing one during testing and this paper shows the difference in the assessing results of these two cases. There is less information how to define the existence of reliability growth rate changing and calculate the parameters of the reliability growth models to make an accurate assessment with such condition, so i established the process and mathematical model to calculate the parameters at such condition to make reliability growth curve with high Goodness of Fit. I validated the new method with the data made from Monte Carlo Simulation and case from Demko (1993). Even the assessed result with the new methodology may be different with the case by case because of very diversity in test condition and testing product quality, but the process and method founded in this research can be applied to any case using Duane and AMSAA model for their test data assessment. I also present the evaluation method to see the effectiveness with new one which is a conventional knowledge and not popular to use, so it is possible to compare the results with the newly presented and conventional method for better business decision.

• Child Health Nursing Research
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• 제9권4호
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• pp.408-419
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• 2003

Purpose: This study was done to develop a reliable and appropriate evaluation tool for sexual educational materials and to apply it to video materials for recommendation of excellent materials. Method: The items of the content for evaluation were based on the previous studies on the sexual education and evaluation tools. After testing validity and reliability of tool, final evaluation tool for sexual educational materials was developed. The evaluation tool was applied to 84 video materials and the excellent materials were recommended. Result: The final evaluation tool for sexual educational materials which consisted of two parts was developed. One is the evaluation of basic information which includes 8 items: target population, type of materials, producer, year of production, subject, theme, running time, and guide book. The other is the evaluation of content which includes 36 items related to characteristics of material, purpose, efficiency and scope of content. After applying the tool to 84 video materials, 39 excellent sexual education materials were suggested. Conclusion: The systematic development of materials for sexual education appropriate to the specific subjects should be done. Producers should describe the basic information on the outside of materials. For recommending the excellent materials, the periodical standardized evaluation of sexual educational materials should be done, and the database of the excellent materials should be provided for further utilization.

• 한국안전학회지
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• 제13권2호
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• pp.65-75
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• 1998

The cases of welders illness by welding fume generated during arc welding are recently reported, which makes the legal regulation in the welding work place. Also, this situation makes the employers and welders be concerned about the welding fume seriously. At this point of time it is necessary that a standard testing method is developed as a fundamental tool for the evaluation of Fume Generation Rate(FGR) required for making progress in the development of low fume electrodes and welding process technology and also constructing the ventilation system in welding area. However, the current standard(KS D 0062) is only applicable to the manual covered electrode arc welding. In this study the evaluation procedure for the FGR is established by developing the fume collection chamber which can be applicable to semiautomatic and automatic arc welding as well as manual arc welding. This evaluation system and procedure can be used as a tool not only to develop the low fume welding electrode and welding process technology but also to construct the equipment controlling the welding workshop atmosphere.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.210-211
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• 2021

This study introduces and demonstrates the application of an experimental regime for anti-seismic performance evaluation of waterproofing materials to used for concrete pile walls. Concrete pile walls are subject to high degree of seismic load, and the occurring stress can affect the waterproofing integrity of the structure, but there is currently no existing methodology or standard for evaluating this property of waterproofing materials. To propose and conduct this evaluation, a new testing apparatus was designed and manufactured intended to be able to test an installed waterproofing material's seismic resistance performance.

• 약학회지
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• 제55권4호
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• pp.324-331
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• 2011

Although the dissolution test can serve as an effective tool for quality control and predictor of in vivo performance, there are a number of drugs with no established dissolution specifications in Korean Pharmaceutical Codex (KPC). Among those commercially available, Piracetam Tablets and Fenoterol hydrobromide Tablets were selected to develop the dissolution testing method. The dissolution condition was determined based on the "Guidelines on Specifications of Dissolution tests for Oral dosage forms" of Korea Food & Drug Administration (KFDA). The dissolution test for Piracetam Tablets was carried out under sink condition with distilled water as dissolution medium, paddle rotation speed at 50 rpm and medium volume of 900 ml. More than 80% of its label claim was released within 30 min. In case of Fenoterol hydrobromide Tablets, distilled water was also found to be suitable to ensure sink condition. The rotation speed of 50 rpm and 900 ml of dissolution medium were used to evaluate the dissolution profile. The dissolution rate of fenoterol hydrobromide was over 90% in 15 min. The HPLC analysis methods were validated in terms of accuracy, precision, specificity, linearity, quantitation limit and range. The results suggested that the analytical methods used are simple and suitable to measure the dissolution rate of piracetam and fenoterol hydrobromide. Therefore, the analysis methods could be utilized in setting dissolution specifications of Piracetam Tablets and Fenoterol hydrobromide Tablets in the revised version of KPC.