• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.6
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• pp.81-90
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• 2015

In order to know the characteristics of the hypersonic air-breahting engine, high altitude and Mach number ground test is necessary. Therefore, high pressure and high temperature condition should be simulated to do ground test of the hypersonic air-breathing engine. In this paper, the hypersonic air-breathing engine ground test facility of the Korea Aerospace Research Institute was introduced and the composition and characteristics were described.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.76-81
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• 2016

At negative-g condition, a float-type valve can open the passage of fuel in order to it flows continuously through a pressurized fuel tank system. Since specialized test conditions and high-cost supports are required, it is truly difficult to test the valve in a real high-speed test. Therefore, this paper contains performance analysis of a float-type fuel supply valve through flight tests conducting roll and negative-g maneuvers.

• ETRI Journal
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• v.4 no.1
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• pp.79-86
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• 1982

• Journal of the Korea Institute of Building Construction
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• v.11 no.5
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• pp.426-434
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• 2011

Recently, the use of mineral admixtures in concrete has been studied in many laboratories, and been applied in the field. But the non-destructive testing equation proposed in Japan for normal strength concrete has been used to determine compressive strength, because there has been a lack of systematic research on the compressive strength of concrete using mineral admixtures. For this reason, it is essential to suggest a non-destructive testing equation to estimate the compressive strength of concrete using mineral admixtures. Therefore, this study made a cylindrical specimen and core tube specimen of concrete using a mineral admixture, and suggested a strength estimation of long-term age (4 years) through non-destructive and destructive tests. The results of the research are as follows. Comparing error rates between conventional suggested equations and this estimated equation shows some differences by age, but the error rate of this study was reduced to 0.3 %~115.0 % compared to conventional equations by re-bound hammering, 0.2 %~22.8 % by the ultrasound velocity method and 0.5 %~102.3 % by complex method. Accordingly, it is judged to be suitable for assessing the compressive strength of concretes using mineral admixtures.

• Water for future
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• v.56 no.9
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• pp.35-46
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• 2023

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.303-311
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• 2008

In the case of bi-directional high pressure pile load test with double-acting jack, the shortcomings of bi-directional pile load test with single-acting jack could be solved, low-cost of test could be sure, the limits of loading capacity could be overcome and quality assurance of service plie could be confirmed. In this study, to confirm the stability, the reliability and the application of bi-directional high pressure pile load test with double-acting jack, the calibration test for high pressure oil jacks, the length of high pressure hose and tunable high pressure pipe system were performed. As a result, credibility was very high because the reliability of test results was approached at about 1.0.

• Journal of the Korean Geosynthetics Society
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• v.7 no.4
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• pp.47-55
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• 2008

The model test and field test for an infiltration trench were carried out to estimate the infiltration quantity in a granular ground with high permeability like Jeju's ground. The specific infiltration equation was suggested on the basis of the model test result. It shows that the infiltration quantity by the proposed equation is larger than about two times of that by the existed equation. Meanwhile, the infiltration quantity from field test is similar to that from the proposed equation as the result of comparison between infiltration quantity of the filed test and that of the proposed equation and the existed equation. Therefore, it may be right that the proposed equation is applied to estimate the infiltration quantity of the infiltration trench in a granular ground with high permeability.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.1-7
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• 2002

The purpose of this research is to obtain a practical expression for the estimation of compressive strength of concrete using non-destructive testing method such as rebound Schmidt hammer and ultrasonic pulse

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.117-125
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• 2000

자가굴착식 프레셔미터 시험(Self-Boring Pressuremeter Test, SBPT)은 지반의 교란을 최소화할 수 있기 때문에 점성토의 비배수 전당강도($S_{u}$ )를 비교적 정확하게 평가할 수 있는 방법 중의 하나로 알려져 있으며, 많은 연구자들에 의하여 SBPT 결과로부터 $S_{u}$ 를 산정하는 여러 가지 방법들이 제안되었다. 본 연구에서는 국내 5개지역에서 총 33회의 SBPT를 수행한후, 기존에 제안된 여러 가지 방법들을 이용하여 $S_{u}$ 를 산정하고, 그 중 변형률 경화 거동을 보이는 지반에서의 $S_{u}$ 를 동일 현장에서 수행한 현장베인시험 결과와 비교. 분석하여 각 방법들의 적용성과 신뢰성을 분석하였다. 그리고, $S_{u}$ 산정 결과에 대한 프레셔미터 멤브레인의 유일한 길이의 영향을 수치해석으로 분석하였으며, 그 결과를 이용하여 기존의 접선영 방법(Subtangent method)을 보정하는 식을 제안하였다. 새로이 보정된 방법으로 산정한 $S_{u}$ 를 현장베인시험 결과와 비교하여 개선 효과를 확인하였다.

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.147-156
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• 1997

지금까지 국내에서는 콘크리트의 크리프에 관한 실험적 연구가 많이 진행되지 못하여 해당 구조물의 설계기술 도입국의 규준에 따라 크리프를 예측해왔다. 그러나 예측된 크리프 모델이 국내 콘크리트 재료의 특성에 적합한지에 대한 실험적 검증은 제대로 이루어지지 않고 있는 실정이다. 본 연구에서는 국내에서 프리스트레스 콘크리트 구조물에 적용하는 실용 고강도 콘크리트의 크리프 값을 예측하기 위해 동일한 설계기준강도를 갖는 세 가지 배합에 대하여 재령별로 크리프 시험을 수행하고 이 실험결과를 ACI, CEB/FIB, KSCE, JSCE규준들의 크리프 예측식과 비교 분석하였다.시험결과와 이들규준들에 대한 비교분석에 의하면 CEB/FIB-90 크리프 예측식은 비교적 과대 평가되고 ACI 209-92와 JSCE-96의 경우는 과소 평가되었으나 콘크리트 표준시방서 KSCE -96 크리프 예측식은 비교적 시험결과에 근접하는 것으로 평가되었다. 그러나 구성재료의 양적 변동에 '따른 배합별 시험결과의 차이를 반영할 수 있는 점이 보완되어야 할 것으로 보며 향후 많은 실험결과를 바탕으로 국내에서 생산되는 콘크리트에 대하여 보다 정확히 크리프를 예측할 수 있는 연구가 필요하다.