• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.137-164
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• 2018

The guarantee of the performance of the engineered barriers in a geological repository is very important for the long-term safety of disposal as well as the efficient design of the repository. Therefore, the performance of the engineered barriers under repository condition should be demonstrated by in-situ experiments conducted in an underground research laboratory. This article provides a review of the major in-situ experiments that have been carried out over the past several decades at underground research laboratories around the world to validate the performance of engineered barriers of a repository, as well as their results. In-situ experiments to study the coupled thermal-hydraulic-mechanical behavior of the engineered barrier system used to simulate the post-closure performance of the repository are analyzed as a priority. In addition, in-situ experiments to investigate the performance of the buffer material under a real repository environment have been reviewed. State-of-the art in-situ validations of the buffer-concrete interaction, and the installation of the buffer, backfill and plug, as well as characterization of the near-field rock and the corrosion of the canister materials are, also performed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.22-29
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• 2023

In the evaluation of seismic performance for structural materials and components, the loading rate and axial force can have a significant impact. Due to time-delay effects between input and output displacements, It is difficult to apply high-rate displacement in cyclic tests and hybrid simulations. Additionally, the difficulty of maintaining a consistent vertical load in the presence of lateral displacement has limited fast and real-time tests performed while maintaining a constant vertical load. In this study, slow, fast cyclic tests and real-time hybrid simulations were conducted to investigate the rate dependency and the influence of vertical loads of Isolation Bearing. In the experiment, the FLB System including an Adaptive Time Series (ATS) compensation and a state estimator was constructed for real-time control of displacement and vertical load. It was found that the vertical load from the superstructure and loading rate can have a significant impact on the strength of the seismic isolation bearing and its behavior during an earthquake. When conducting experiments for seismic performance evaluation, they must be implemented to be similar to reality. This study demonstrates the excellent performance of the system built and used for seismic performance evaluation and enables accurate and efficient seismic performance evaluation.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.55-56
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• 2006

냉매 충전량과 이차유체의 입구조건은 $CO_2$용 열펌프시스템의 성능실험에서 중요한 제어변수이다. 따라서, 열펌프사이클의 적용과 난방성능 향상을 위해 제어변수의 특성을 조사하는 것이 필요하다. 본 논문에서, $CO_2$용 열펌프 사이클의 성능 실험은 여러 가지 냉매 충전량에서 이차유체 입구조건에 변화를 주어 수행 되었다. 실험결과, 난방COP는 냉매 충전량이 증가함에 따라 1158g의 냉매 충전량에서 최대가 되었다가 감소하는 경향이 나타나며, 이는 COP가 최대가 되는 냉매충전량이 존재함을 나타낸다. 또한, 난방성능은 가스쿨러내 이차유체의 질량유량의 증가에 따라 증가하였다. 가스냉각기내 2차유체의 입구은도가 $10^{\circ}C$에서 $40^{\circ}C$로 증가하면, 난방용량, 압축일량, 토출압력은 각각 -8.57%, -35.89%, 32.78%로 변화했으며, 증발기 2차유체의 입구 온도가 감소하였을 때 난방COP는 감소하는 경향을 보였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.6
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• pp.1-7
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• 2009

The gas turbine engine performance is greatly relied on its component performance characteristics. Generally, acquisition of component maps is not easy for engine purchasers because it is an expensive intellectual property of gas turbine engine supplier. In the previous work, the maps were inversely generated from engine performance deck data, but this method is limited to obtain the realistic maps due to calculated performance deck data. Therefore this work proposes newly to generate more realistic compressor map from experimental performance test data. And then a realistic compressor map can be generated form those processed data using the proposed extended scaling method at each rotational speed. Evaluation can be made through comparison between performance analysis results using the performance simulation program including the generated compressor map and on-condition monitoring performance data.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.445-452
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• 2012

In this study, experimental research was carried out to evaluate the structural performance of the reinforced concrete beam using strengthening materials (embedded FRP rod, metal fittings) in existing reinforced concrete buildings. Seven reinforced concrete beams comprised of retrofitted embedded FRP rod (BCR series), embedded FRP rod with metal fittings (BCR-AC series), and standard specimen (BSS) were constructed and tested under monotonic loading. Design parameters of test specimens were amount of embedded FRP rod and metal fittings. The test results showed that the maximum load carrying capacity of specimens with embedded FRP rod (BCR series) and embedded FRP rod with metal fittings (BCR-AC series) increased by 21~55% and 21~63%, respectively, in comparison with the standard specimen BSS. BCR series test specimens failed by the adhesion slip and concrete cover separation. BCR-AC series test specimens failed by the adhesion slip due to the confining effect of metal fittings.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.591-601
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• 2011

An experimental study was performed to evaluate the seismic performance of beam-column connections using 600 MPa re-bars for beam flexural reinforcement. Three full scale specimens of interior beam-column connection and two specimens of exterior beam-column connection were tested under cyclic loading. The specimens were designed to satisfy the requirements of Special Moment Frame according to current design code. The structural performance of the specimens with 600 MPa re-bar were compared with that of the specimen with 400 MPa re-bars. The test results showed that bond-slip increased in the beam-column joint. However, the load-carrying capacity, deformation capacity, and energy dissipation capacity of the specimens with 600 MPa re-bar were comparable to those of the specimens with 400 MPa re-bars.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.477-484
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• 2013

In this study, eleven reinforced concrete beams, ground granulated blast furnace slag, replacing recycled coarse aggregate (BRS series) and recycled coarse aggregate with steel fiber (BSRS series), and standard specimen (BSS) were constructed and tested under monotonic loading. Experimental programs were carried out to improve and evaluate the shear performance of such test specimens, such as the load-displacement, the failure mode and the maximum load carrying capacity. All the specimens were modeled in 1/2 scale-down size. Test results showed that test specimens (BSRS Series) was increased the compressive strength by 9%, the maximum load carrying capacity by 1~6% and the ductility capacity by 1.02~1.13 times in comparison with the standard specimen (BSS). And the specimens (BSRS Series) showed enough ductile behavior and stable flexural failure.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.83-84
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• 2010

Precast beam column joints with thru-connectors are developed from precedent study. The seismic performance is evaluated by experimental method. The test results of the precedent study showed that failure modes for all specimens were a compression failure by characteristics of unbonded tendon. Thus, variable considered in the research program for a tensile failure include the use of dog-boned longitudinal steel and concrete confined with steel spirals. The analysis of structural characteristics and evaluation of seismic performance of specimens was conducted by the experimental way. Comparison of result with the test specimens indicates that seismic performance is higher than the precedent study due to concrete confinement effect from steel spirals.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.69-75
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• 2017

Ultra-high performance concrete and high ductile cementless composite are considered as promising construction materials because those exhibits higher performance in terms of high strength and high ductility. The purpose of this study is to investigate experimentally the compressive strength and tensile behavior of ultra-high performance concrete and high ductile cementless composite. A series of experiments including density, compressive strength, and uniaxial tension tests were performed. Test results showed that the compressive strength and tensile strength of alkali-activated slag based high ductile cementless composite were lower than those of ultra-high performance concrete. However, the tensile strain capacity and toughness of alkali-activated slag based high ductile cementless composite were higher than those of ultra-high performance concrete. And it was exhibited that a high ductility up to 7.89% can be attainable by incorporating polyethylene fiber into the alkali-activated slag based cementless paste.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.326-329
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• 2008

현재 IEEE 802.11p 규격은 기존의 IEEE 802.11a 규격을 기반으로 하여 표준화가 진행되고 있다. 기존의 IEEE 802.11a 규격은 무선랜 (WLAN: Wireless Local Area Network) 규격으로서 고속으로 이동하는 차량 통신환경 즉 WAVE (Wireless Access for Vehicular Environment) 환경에 그대로 작용할 경우 수신 성능이 급격히 떨어지게 되 는 문제점이 있다. 본 논문에서는 긴 훈련 심볼 (LTS: Long Training Sequence)을 이용하는 기존의 채널 추정 기법을 기반으로 하되 WAVE 채널처럼 빠르게 변화하는 채널에 대응하기 위해 일정한 심볼 주기 마다 미드엠블 (Mid-Amble)을 삽입하는 전송구조를 제안한다. 또한, 미드엠블 사이의 심볼들의 위상과 크기를 3차원 스플라인 보간법을 적용하여 추정하는 알고리듬을 제안한다. 제안된 알고리듬의 성능실험을 위해 WAVE 채널을 모델링하였으며 이러한 채널에서 성능실험을 수행하였다. 실험결과에 의하면 제안된 알고리듬은 빠른 시변 채널에서도 매우 우수한 성능을 나타냄을 알 수 있다.