• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.740-746
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• 2009

Two step serial load induction superheater has been proposed using resonance type induction heat method in this paper. Heat method is a type of flowing the electron induction and current to special alloy heater in body from external heat coil with non-contact method. Inverter was a full bridge serial load resonance type and inductor was used as load in LC resonance design to maximize the efficiency. The developed system is a new heat exchanging method combined with electromagnetic induction heater and fluid movement, ana very accurate to control of heating the gas, liquid and evaporated mass, so on without combustion process.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.53-54
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• 2009

Steel-embedded composite piers provide flexible design alternatives to satisfy the required performance due to various design parameters of composite sections. For the fast construction of composite piers, bolt connection can be utilized for small size piers and post-tensioning to the pier segments for the large size piers. In this paper, experimental results on composite piers were investigated to evlauate the effects of design parameters on the behavior of composite piers. Appropriate sections and their integration methods were suggested according to the design conditions. For the modular construction of bridge piers, pier segments need to be divided considering their weight and careful considerations on details to adjust fabrication and construction error. Connection details for the pier cap were also proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.687-695
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• 2020

Micropile is used to improve the stability of existing structures as well as solve various geotechnical problems, such as suppressing slope activity and shearing keys of retaining walls. The existing micropile method has a significantly less capacity to resist a horizontal force than a vertical force0355 Therefore, it is necessary to develop and study an umbrella-type micropile method with excellent seismic performance that can secure seismic performance economically while minimizing structures and ground disturbance areas in the limited space of existing structures. In this study, numerical analysis was performed on the umbrella-type micropile, in which the sloped pile and vertical pile were combined, and the horizontal behavior in soft clay ground during earthquakes was analyzed. Numerical analysis showed that umbrella-type micropile suppresses horizontal displacement in soft ground, and the effect of reducing the horizontal displacement was more pronounced when the embedded depth of the slope pile was 15 m or more. The embedded depth of the micropile and horizontal displacement suppression effect was proportional. Therefore, the umbrella-type micropile has an excellent effect of suppressing horizontal displacement during earthquakes on soft clay ground.

• The Magazine for Energy Service Companies
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• s.54
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• pp.64-69
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• 2008

야간의 잉여전력으로 열을 저장해두었다 주간에 이용하는 축열공조에는 50여년에 걸친 긴 역사가 있었다. 이 방식이 가지는 효용에 일찍부터 눈뜬 선각자들의 노력에도 불구하고 당초 보급은 늦어져 그다지 진전이 없었다고 한다. 이러한 정세가 일변한 것은 전력공급에 병목현상이 생겨 부하 평준화가 안정공급에 있어 필요불가결의 과제가 되었기 때문이다. 특히 공조는 피크성이 강한 수요이므로 공조용 전력을 야간으로 옮기는 작업의 이점이 큰 것은 당연하다. 비 수요시간대의 요금이 큰 폭으로 떨어짐으로써 수요자측에서 보아도 야간의 전력을 어떻게 활용할까하는 것은 매력적인 연구테마였다. 이리하여 축열공조가 관심을 불러 보급이 기도에 놓인 지 2O년 가까이 되었다. 처음에는 물을 사용한 축열이 대부분이었으나, 축열조 용량의 제약으로 얼음을 만들어 저장하는 빙축열방식이 도입되어 현재의 표준적인 축열방식이되었다. 그러나 빙축열에도 비용상의 문제가 있어 전면적인 보급에 이르기까지는 아직 연구의 여지가 더 남아있는 듯하다. 한편, 교토의정서의 발효 등에 의해 지구환경에 대한 관심이 높아지게 되었다. 이 같은 배경 속에 건물및 건축설비의 에너지절약 기술의 중요성이 대두되고, 특히 창 주변의 공조방식, 조광제어, 축열 공조시스템 등, 건물부하의 직접적인 저감과 전력부하 평준화에 의한 환경부하저감 및 운영비용의 저감을 목적으로 한 건물일체형 설비시스템을 적극적으로 도입하기에 이르렀다. 환경을 배려한 건축구조.설비시스템의 채택 사례가 증가하며 건축물 종합환경성능 평가시스템과 성능검증 등 건물설비의 평가.검증 수법도 연구되어 건물에 적합한 운용면에서의 사고가 중요함이 인식되었다. 이와 같이 건축구조와 설비시스템의 양면에서 에너지절약성 및 환경성, 쾌적성, 편리성의 추구가 적극적으로 도입되는 가운데, 슬래브축열시스템은 건축구조와 공조설비가 균형있게 융합됨으로써 초기비용의 삭감과 부하 평준화에 의한 경제성 향상, 복사에의한 실내환경의 향상 등의 효과를 기대할 수있는 시스템으로 추목받고 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.183-190
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• 2006

From the result of this research above, it may be summed up as follows. As a summary of results from each experiment, as the test body reinforced with the carbon rods was embedded inside the concrete section and made it possible uniform movement, this study has shown that it had excellent characteristics in improving the flexural strength and ductility. Also, it was considered as the carbon-steel sheet composite plate was to exert the strength more if it would complement the adherence with the concrete.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.665-674
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• 2015

The final goal of this research is to develop a botanical biofiltration system, which combines green interior, biofiltering, and automatic irrigation, which can purify indoor air pollutants according to indoor space and the size of biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be more suitable for indoor space utilization. This study was performed to compare indoor air quality between the space adjacent to a botanical biofilter and the space away from the biofilter (control) without generation of artificial indoor air pollutants, and to evaluate plant growth depending on multiple floors within the biofilter. Each concentration of indoor air pollutants such as TVOCs, monoxide, and dioxide in the space treated with the biofilter was lower than that of control. Dracaena sanderiana ‘Vitoria’ and Epipremnum aureum ‘N Joy’ also showed normal growth responses regardless of multiple floors within the biofilter. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was effective for indoor air purification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.74-79
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• 2019

The military vehicle produces electric power through an engine-integrated serial hybrid generator that is connected to the engine and does not have a separate generator installation space. However, depending on the mechanical characteristics of the connection between the generator and the engine, iron oxide for internal rusting and lubrication grew scattered. The iron oxide is adhered to the starter to deteriorate the starting performance, and there is a problem that the noise of the leg due to wear of the gear is increased. To solve this problem, the connection spline material and the surface treatment of the engine were improved and the shape was changed to a grease sealing type to prevent the generation of iron oxide inside. As the shape of the generator connector composing the shafting system was changed, the integrity of the structure was confirmed through the torsional endurance test. In addition, through the actual vehicle load test, it was verified that no corrosion occurred during the target life span without internal corrosion. It was confirmed that the anti-scattering structure of the grease effectively suppresses the generation of iron oxide, thereby reducing the noise generated from the generator. In this paper, we propose a fundamental solution to the degradation of the starter and the noise generation by preventing the back corrosion caused by the serial hybrid generator installed between the engine and the transmission.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.550-559
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• 2022

Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the safety by flow analysis of the 6.35 inch socket model, which are integrated insert type connectors developed by a company, using CFD analysis technique. For CDF analysis, RAN model and LES model are used. Result: As results of the analysis, amplitude of the pressure fluctuation acting on the wall of the piping system is formed at a level of 3,780 Pa or less, which is a very small level of pressure compared with the operating pressure or design stress of the refrigerant piping. Conclusion: These results mean that the effect of vibration caused by turbulence on the structural safety of the pipe is negligible.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.129-136
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• 2012

Temperature of fresh concrete can be effectively used to predict the strength of concrete being cured and make an informed decision for stripping the molds. A hygrothermograph and thermo-couple sensors that require an extensive wiring have been applied to measure a temperature of concrete at the early stage of the curing process on site. However, these methods have limits to provide the temperature data in real time due to harsh working environment including frequent cutting of wires. Therefore, this study is aiming at developing a device based on wireless sensor network to measure the temperature of concrete being cured in formwork. The result showed that the wireless sensor with probe type thermistor which is developed had the same temperature data compared to the existed wire type thermistor, and we confirmed the temperature history of concrete in real time for 28 days throughout the gateway by wireless network that collects the temperature data measured from specimens in laboratory. Also, the network device for transmission can be easily separated from the probe sensor part and reused consistently. If the wireless sensor network device developed uses in the field, the temperature management of concrete will be systematically conducted from at the early stage of the curing, and especially be effective for cold weather concrete construction. In addition, it will contribute to the establishment of advanced quality control system for concrete and productivity of supervisors on site will be increased in the future.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.435-440
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• 2004

The nonlinear impacts between the Control Element Drive Mechanisms (CEDMs) seismic cap plates installed on the CEDM top of a pressurized water reactor are studied with the dynamically reduced models of the CEDM and Integrated Head Assembly (IHA). It is important to develope nonlinear models considering the gap effects between the plates. In order to simulate impacts, reduced models for the primary structures, such as CEDM and IHA, are developed through simplifying detailed models, and the nonlinear structural analysis is performed under seismic loading conditions. The responses are examined in various gap sizes depending on the reactor operating conditions.