• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.5
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• pp.410-417
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• 2006

The present study predicted the effect of the flow rate of coolant on the absorption performance of a vertical falling film type absorber Heat and mass transfer peformances were numerically investigated. The exit temperatures of solution and coolant were decreased as the flow rate of the coolant was increased at the film Reynolds number of 100. The absorption mass flux was increased and then decreased as the distance from the inlet of the absorber was increased. The distance showing the maximum absorption mass flux was ranged from 0.3 to 0.5m. The heat flux and the absorption mass flux were increased and then slowly decreased as the flow rate of the coolant was increased. The maximum values were obtained at the flow rate of coolant of 2.0L/min.

• Journal of Korean Association for Spatial Structures
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• v.11 no.3
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• pp.67-76
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• 2011

Column base is very important part of steel structure because it transmits load to foundation in structure. Column base which is used frame construction in the inside and outside of the country is distributed into exposed-type, concrete encased and imbeded-type. Exposed-type column base is most profitable, if consider reuse and recycle of elements first of all. In this study, we proposed a new style exposed-type column base improved in performance for construction work and mechanical performance.

• Fire Science and Engineering
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• v.29 no.1
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• pp.53-59
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• 2015

Water hammering created by an unsteady flow in pipeline systems can cause excessive change in pressure, vibration, and noise. So, water hammer analysis is very important for limiting the damage caused to pipeline, pump and valve systems by operation conditions. On the other hand, water hammer arrester has been manufactured and used in order to minimize the damage caused by water hammering phenomenon in domestic, and it has been produced and installed as the low cost-oriented because of being no separate standard in the meanwhile. Therefore, our research team investigated about the standardization of water hammer arrester performance through the various methods, such as test methods for verification of one pipe, assuming the occurrence of water hammer in a water-based fire extinguishing system, separated for opening impact pressure and shut off impact pressure and for a branch pipe in order to make guideline for water hammer arrester performance. And finally, verified the performance of the water hammer pressure as the simple mechanical way using the U-shaped pipe and a test weight, so KFI standards for the water hammer arrester could be established.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.23-27
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• 1996

$\beta$-선 흡수선량의 1차 표준이 확립되지않은 상황에서 측정표준이 이미 확립된 외국의 표준기관에서 검증되어 도입된 $\beta$-선 흡수선량 조사시설에 대해 ISO-6980에서 명시한 항목에 대해 성능실험을 수행하였고, 외삽형전리함을 사용하여 측정된 이온화전류로 부터 흡수선량률을 재평가하여 외국의 검증결과와 비교하였다. 조사시설의 성능실험 결과 Sr$^{90}$ +Y$^{90}$ 선원에 대해 선원으로부터 30cm거리에서 빔 균일도, 제동복사선 기여도 및 $\beta$-선 최대잔여에너지가 기준에 적합한 것으로 나타났다. 그리고 흡수선량 평가결과는 '96. 4. 1을 기준으로하여 20 $^{\circ}C$,1기압에서 2.686 ($\pm$2.73%)$\mu$Gy/sec로 외국표준기관의 측정치와 1.8%이내에서 일치하는 것으로 나타났다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1113-1118
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• 2010

It is requested that the interior compartment of a passenger vehicle must be satisfied with the FMVSS201U regulation, FMH impact test. It is needed the design methodology to find the appropriate structure about the FMH impact. When designing the impact-absorbing structure for the FMH impact test, it is to be noted that the impact absorber must have different performance considering the stiffness of the vehicle as the impact position and approach angle of FMH. In this study, an efficient design methodology was developed by using subcomponent collapse simulation instead of conducting full-vehicle simulation, thereby reducing the time and resources spent. Further, this unit-model simulation helps optimize the impact absorbing structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.3
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• pp.37-43
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• 2001

The energy concept has been extended to compare the hysteretic performance between various structural systems. As a result, the energy absorption efficiency is defined as the cumulative energy absorption capacity of a structural system normalized by that of the elasto-perfectly plastic system as a benchmark for comparisons. For this, the construction of energy curves from the experimental results obtained by cyclic loading tests is required. Using the proposed procedure, structures differing from each other in geometry, material and construction can be relatively and objectively compared for seismic performance. Also the beauty of this method is in its irrelevance to the structural failure mode. The proposed procedure was validated by application to the experimental results of two different specimens.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.399-407
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• 2022

Energy absorption facilities installed on roads should follow the performance standards of the real-car crash test of 'Installation and Maintenance Guidelines for Roadside Safety Facilities'. However, due to different installation conditions, such as differing structure widths on roads, some energy absorption facilities do not provide adequate performance. In order to apply varied environments on roads, an energy absorption structure was designed in this study with 150 mm height and four layers of W-shape guardrail at 200 mm intervals, and the performance was verified using LS-DYNA computer simulation. Through a real-car crash test, the performance of the facility designed by LS-DYNA was tested and was found to meet the performance of the CC2 category for crash cushions. The conclusion of the comparison demonstrates that the simulation and the real-car crash tests are both significant.

• Journal of Climate Change Research
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• v.2 no.2
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• pp.107-113
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• 2011

In this research, we described the experimental results for the improvement of Potassium based sorbents. These sorbents have been actually used in the 0.5 MW $CO_2$ capture plant located in Hadong #3 Power Plant. Firstly, we had shaped two kinds of sorbents using a spray dryer. These sorbents applied magnetite & copper oxide as an additive. And the magnetite sorbent was evaluated more excellent relatively in the attrition index. Secondly, We had obtained TGA multicycle experimental results of the improved Potassium based sorbent which applied magnetite as an additive. Consequently, $CO_2$ sorption capacity had been sustained 5.5 wt% after 2nd cycle and attrition index was very excellent as 0.5%. Finally, we had investigated the characteristics of the sorbent following in properties of supporters. As a result, the sorption capacity of the KMO sorbent used base material as a supporter was appeared as 7.2 wt%.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.161-165
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• 2002

인류가 직면한 환경 및 에너지 문제를 타개하기 위한 많은 연구 중 흡수식 열펌프는 환경친화적인 자연냉매를 사용하는 열구동 시스템으로 다시 주목을 받고 있다. 흡수식 열펌프의 구성요소 중 흡수기는 암모니아의 흡수에 의한 열 및 물질전달 현상이 동시에 일어나는 곳으로 암모니아-물 열펌프 시스템의 성능 향상을 위해 가장 중요한 부분이다.(중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.3
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• pp.7-10
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• 2004

삼중효용 흡수식 냉동기의 기본 원리, 사이를 구성 방법 및 특성, 제품 개발을 위한 핵심 기술에 대하여 알아본다. 현재 널리 사용되는 흡수식 냉동기는 대부분이 이중효용(double effect) 기기이며 그 동안의 많은 기술 축척과 연구개발의 결과, 성능이 향상되어 최근 일본에서 출시되는 신제품은 냉방 COP가 약 1.3을 넘어서고 있다. 그러나 이중효용 흡수식 냉동기로서는 도달 가능한 COP에 한계가 있기 때문에 2-3년 전부터 삼중효용 흡수식 냉동기에 대한 연구가 일본 등에서 활발히 진행되고 있다.(중략)