• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.236-239
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• 1995

50 kW$_{th}$ 용량의 기체연료버너에서 암모니아 기체와 요소용액을 이용한 선택적 무촉매 환원법 (SNCR;Selective Non-catalytic Reduction) 으로 질소산화물 (NOx) 저감에 관하여 연구하였다. 암모니아는 요소요액보다 더 낮은 반응온도에서 더 높은 효율을 보여주지만 경제성과 암모니아의 부식성 및 맹독성으로 인하여 취급하기에 곤란한 점이 있다. 반면에 요소용액은 적절한 액상첨가제와 기상첨가제를 사용하여 넓은 반응온도범위에서 높은 효율을 얻을 수 있으며 공정상의 조업비를 절감할 수 있다. 본 실험에서는 액상 첨가제인 $CH_3$OH 와 $C_2$H$_{5}$OH 을 사용하여 5$0^{\circ}C$ 정도의 최적반응온도 감소를 얻었으며 LPG 와 합성가스(CH$_4$:CO:H$_2$:$CO_2$=1:4:4:2) 틀 기상 첨가제로 사용하여 높은 질소산화물 저감 효율을 관찰하였다.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.195-200
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• 2013

New thermal crack control system for mass concrete was developed to increase quality and to save construction period and cost. The principle of this system is that the curing water having proper temperature is supplied automatically to the surface of mass concrete member to keep the temperature difference between center and surface of concrete less than generally recommended temperature difference ($20^{\circ}C$). Mock-up test was conducted to investigate the validity of newly developed curing system. As a result, no crack was founded in the specimen using automated curing system developed in this study, while many cracks occurred in another specimen without automated curing system. It was also confirmed that the strength and the durability of the concrete cured by automated curing system were improved.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.79-89
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• 2019

The field measurement and laboratory experiment were conducted to investigate the effect of reducing the surface temperature of the functional aspect of the heat island phenomenon of the permeable block which is made the recycled synthetic resin rather than the existing concrete permeable block. Field measurement was taken for 3 days in consideration of dry condition and wet condition and laboratory experiment was divided into dry condition, rainfall simulating condition, and wetting condition. The variations of temperature and the evaporation rate of water moisture content after experiment were confirmed. As a result of field measurement, it is confirmed that the surface temperature decreases due to the difference in albedo of the pore block surface rather than the cooling effect due to the latent heat of vaporization. The evaporation of moisture in a dry state where drought persisted or a certain level of moisture was not maintained in the surface layer. As a result of laboratory experiment, resin permeable block gives higher surface temperature when it is dry condition than concrete permeable block, but the evaporation of water in the pore is kept constant by capillary force in rainfall simulation condition, and higher temperature reduction rate. As a result of measuring the evaporation rate after laboratory experiment, it is confirmed that the effect of reducing temperature is increased as the evaporation rate of water is higher. Based on these results, correlation formula for evaporation rate and temperature reduction rate is derived.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.21-22
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• 2006

디젤엔진에서 배출되는 배기가스 중의 주요 오염물질 중의 하나인 NOx(질소산화물)는 대부분 고온의 연소 과정에서 발생하고, 발생량은 연소온도에 따라 결정되는 것으로 알려져 있다. 또한 연료의 연소 중에 물이 첨가되면 연소공기의 비열 증가에 의하여 연소온도가 감소하여 NOx 발생량이 급격하게 감소하게 되는데, 연소실에 물을 첨가하는 방법으로는 유화연료, 직접물분사, 흡기가습 등이 있다. 이중 흡기가습은 구조가 간단하면서 NOx 저감효율이 가장 높은 것으로 알려져 있다. 본 연구는 당사 고유모델 중형엔진인 힘센엔진에 흡기가습 기술을 적용하여 연소성능 및 NOx 저감효과 등을 시험하고, 흡기가습 시스템의 상용화 모델 개발을 위한 기초 데이터를 확보하기 위해 수행되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1705-1710
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• 2008

In this paper, a program for simulating hydration heat and stresses was developed. And an effective methods were proposed for reduction of hydration heat stresses using flyash and steel fiber. It was shown that flyash replacement made reduction of peak temperature due to hydration heat. However, the effectiveness of reduction of tensile stress was not as good as it of peak temperature. Not only peak temperature but also tensile stress were reduced by the addition of steel fiber.

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.555-560
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• 2008

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.189-196
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• 2020

When concrete member become large like in high rise buildings, hydration heat makes temperature difference inside and outside and cause cracks. The method of using latent heat material as heat reducer could be more accessible, usable and efficient than other methods. Therefore, many studies using PCM as heat reducer are being conducted. Since heat reducer have different reacting temperature, they may be affected by environmental factors like ambient and concrete mixing temperature but studies issuing this are insignificant. Therefore, this paper attempt to evaluate the hydration heat characteristics and quality of concrete using strontium-based PCM under hot weather conditions. As a result, when the strontium-based hydration heat reducer was mixed 3wt.% and 5wt.% in hot weather condition, hydration heat speed and heating rate could be reduced by 8%, 21%, and 75, 85 minutes compared to OPC, respectively. This is considered to be the phase change reaction is relatively promoted when the temperature is high and cause improve performance than room condition result. Later, comparing the efficiency of other types of P.C.M in hot weather condition, and conduct detailed reviews on the strength development in long-term age.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.294-301
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• 2022

In this study, a multi-layer cascade (MLC) electrical array configuration method for thermoelectric generator consisting of plural number of thermoelectric modules (TEMs) was proposed to reduce mismatch loss caused by temperature maldistribution on the surfaces of the TEMs. To validate the effect of MLC on the mismatch loss reduction, a numerical model capable of reflecting multi-physics phenomena occuring in the TEMs was developed. MLC can be employed by placing a group of TEMs experiencing relatively low temperature differences in an electric layer with more electrical branches while locating a group of TEMs experiencing relatively high temperature differences in an electric layer with less electrical branches. The TEMs were classified using the temperature distribution obtained by the numerical model. A MLC with an optimal electrical branch ratio showed a 96.5% of electric power generation compared to an ideal case.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.497-500
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• 2008

This research carries out experiments for hydration exothermic rate and adiabatic temperature rise of concrete to examine the characteristics of the hydration heat of high flowing self-compacting concrete with a normal strength. As a result of the hydration exothermic rate experiment, the high flowing self-compacting concrete that used Lime stone powder and fly ash as polymers shows that its hydration heat amount reduces due to the reduction of unit cement. The result measured the adiabatic temperature rise of concrete presents that high flowing self-compacting concrete having lots of binder contents has a good performance in temperature reduction due to the effect of polymer and that triple adding high flowing self-compacting concrete has a similar temperature rise speed with conventional concrete. As a result of the research, high flowing self-compacting concrete shows a better temperature reduction performance for the binder content per unit than conventional concrete. In addition, it is judged that triple adding high flowing self-compacting concrete with a specified concrete strength 30 MPa is more beneficial in temperature reduction and early hydration heat than double adding high flowing self-compacting concrete.

• Journal of the Korean GEO-environmental Society
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• v.18 no.1
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• pp.5-12
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• 2017

The damage of the tunnel lining on the cold regions can be represented by cracks and leaks caused by freezing of ground water. However, domestically, the relevant construction guidelines are not provided so far. Thus, in this research, the mechanical behavior and thermal conductivity of designated tunnel area are measured using instrumentation system installed in the lining concrete inside tunnels in order to analysis their behavior with regard to temperature variations. Previous research mainly focused on the effect of temperature on the tunnel lining based on the air and initial ground temperature at urban regions. Thus, this study analyzes effects of air temperature and initial ground temperature of designated tunnel area at the cold regions. The temperature of the groundwater at the backfill of the tunnel lining are analyzed to evaluate the heating element. Numerical analyses are performed to evaluate the heating element with regard to the various initial ground temperatures.