• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.333-339
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas funnel connected to combustion chamber of greenhouse heating system. The experiment heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas funnel, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amount by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air pipes and exhaust air passages crossing the pipes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through funnels.

• 설비공학논문집
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• 제26권6호
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• pp.287-293
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• 2014

Internal combustion engines release 30~40% of the energy from fossil fuels into the atmosphere in the form of exhaust gases. By utilizing this waste heat, plenty of energy can be conserved in the auto industry. Thermoelectric generation is one way of transforming the energy from engine's exhaust gases into electricity in a vehicle. The thermoelectric generators located on the exhaust pipe have been developed for vehicle applications. Different experiments with thermoelectric generators have been conducted under various test conditions as following examples: hot gas temperature, hot gas mass flow rate, coolant temperature, and coolant mass flow rate. The experimental results have shown that the generated electrical power increases significantly with the temperature difference between the hot and the cold side of the thermoelectric generator and the gas flow rate of the hot-side heat exchanger. In addition, the gas temperature of the hot-side heat exchanger decreases with the length of the thermoelectric generator, especially at a low gas flow rate.

• 설비공학논문집
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• 제26권7호
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• pp.329-334
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• 2014

This study indicated the possibility of energy regeneration from waste coolant heat, by using thermoelectric generation integrated with heat pipe. The internal combustion engine rejects more than 60% wasteful energy to the atmosphere by heat. The thermoelectric generator has recently been studied, to convert the energy from engine waste heat into electricity. For coolant waste heat recovery, a thermoelectric generator was investigated, to find out the possibility of vehicular application. Performance characteristics were conducted with various test conditions of coolant temperature, coolant mass flow rate, air temperature, and air velocity, with the thermoelectric generator installed either horizontally or vertically. Experimental results show that the electric power and conversion efficiency increases according to the temperature difference between the hot and cold side of the thermoelectric generator, and the coolant flow rate of the hot side heat exchanger. Performance improvement can be expected by optimizing the heat pipe design.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.227-232
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• 1996

The one-third calibrating relation by steady solution can cause large error when applied to an unsteady flow with large amplitude waves. Extended calibrating method, which can treat the normal convective contribution, is developed. The normal mass convective term is included into the 2-D mass transport equation by means of rms value and random function. The unknown shear rate is numerically determined by solving the 2-D mass transport equation inversely. This recovery method which predicts the unknown shear rate is constructed. It is found that it works very well without distortion. The inclusion of the normal convective term has a negligible effect on the mass transfer coefficient.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.101-116
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• 2002

Modern vehicles require a high degree of refinement, including good driveability to meet customer demands. Vehicle driveability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore, Engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes analysis procedures using a mathematical model which has been developed to simulate spark timing control logic. Inertia mass moment, stiffness and damping coefficient of engine and drive train were simulated to analyze the effect of parameters which were related vehicle dynamic behavior. Inertia mass moment of engine and stiffness of drive line were shown key factors for the shuffle characteristics. It was found that torque increase rate, torque reduction rate and torque recovery timing and rate influenced the shuffle characteristics at the tip-in condition for the given system in this study.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.644-648
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• 2001

The biological control potential of entomopathogenic nematodes (EPN) can be enhanced by improved culture efficiency. Optimization of the media is a key factor for improving in vitro mass production of entomopathogenic nematodes. This study reports the effect of medium concentration. The medium is a combination of carbohydrates, lipids, proteins, sats, and growth factors, on the growth of Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus liminescens. The overall optimal medium concentration for nematode recovery, hermaphrodite size, bacterial mass, infective juveniles (IJs) yield, and doubling time was 84 g/l. At this concentration rate, the doubling time of IJs production and the biomass of symbiotic bacteria was 1.6 days and 12.8 g/l, respectively. The maximum yield of $2.4{\times}{10^5}IJs/ml$ was attained within a one-generation cycle (eight days). The yield coefficient was $2.8{\times}{10^6}$ IJs/g medium, and the maximum productivity was $3.1{\times}{10^7}$ IJs per day. Medium concentration affected two independent factors, recovery and hermaphrodite size, which in turn influenced the final yield.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.411-415
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• 2008

이 논문은 고도모사 시험설비의 전체 사양을 결정에 관계되는 엔진 입구에서의 고도비행 경험을 위한 모의대기 요구 조건, 모의 비행중 쇼요되는 연료 소모량 및 공급 방법, 시험모드별 냉각부하 예측, 효과적인 압력 회복률을 위한 배기 이젝터의 최적형상 결정에 관한 고려사항을 기술하였다. 이를 위하여 엔진의 연료소모량을 고려한 엔진 배기가스의 온도 및 배출량 등의 계산을 수행되었다.

• 대한환경공학회지
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• 제39권1호
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• pp.40-49
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• 2017

본 연구에서는 경기도 고양시 소재 I 수질복원센터의 공정별 유량과 총인(TP) 농도를 활용하여 2015년도 기준 TP 물질수지도를 작성하고, 이를 분석하여 하수처리시설에서 인(P)을 회수할 수 있는 최적의 단위공정을 실증적으로 선정하고자 하였다. 인 회수공정의 도입 가능성을 평가하기 위하여 유량, TP농도, TP부하량 및 SS에 대한 정량적 지표를 제안하는 한편, 이를 I 수질복원센터에 적용하였다. 또한 I 수질복원센터의 탈수여액을 대상으로 인 회수공정의 도입 가능성에 대한 기초실험을 실시하였다. TP 물질수지를 분석한 결과, 하수처리장 유입수에 비해 유량은 1/16로 적지만 TP농도는 약 78배, TP부하량은 4.8배에 달하는 반류수 계통을 대상으로 인을 회수하는 것이 하수처리시설 전체의 TP부하를 저감하는데 유효한 것으로 나타났다. 반류수 계통의 단위공정들을 대상으로 본 연구에서 제안한 정량적 지표를 활용하여 인 회수공정의 도입 가능성을 상세히 평가한 결과, (잉여농축조 상징액+잉여저류조 월류수) 또는 탈수여액이 적합한 것으로 나타났다. 한편, TP농도가 141.5 mg/L에 달하는 탈수여액을 대상으로 결정화에 의한 인 회수 기초실험을 실시하였다. 탈수여액의 pH를 10으로 조정한 후 칼슘이온($Ca^{2+}$)을 각각 250, 500, 1000 mg/L씩 주입하여 완속교반을 실시하였다. 기초실험 결과 탈수여액 중의 $PO_4-P$ 및 TP를 95% 이상 제거할 수 있는 것으로 나타나 인 회수공정의 도입 가능성이 확인되었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.294-299
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• 2005

In order to control indoor air quality and save energy. it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. Paper heat exchanger can recover $50{\sim}70$ of the enthalpy difference between supply and exhaust air. The purpose of this research is to obtain the experimental correlations for the friction factor, heat transfer coefficient, mass transfer coefficient and permeance of paper heat exchanger, which can be used for the performance prediction of the paper heat exchanger. Pressure drop at various velocities and heat transfer rate at various dry-bulb temperatures, relative humidities, and specific humidities are measured to make experimental correlations. The results of prediction using correlations show fairly good agreement with experimental data.

• 한국항공우주학회지
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• 제30권6호
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• pp.46-52
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• 2002

액체로켓 추진제 공급장치에 정착된 캐비테이션 벤튜리의 유량 제어 특성을 해석하였다. 해석에는 실험과 수치해석이 병행되었으며 캐비테이션이 존재하는 유동에서 두 결과의 유량 차이는 약 10%로 나타났다. 벤튜리 상류의 압력을 $22.8{\times}10^5$pa로 일정하게 유지하고 하류의 압력을 변동시켰을 때 $3{\times}10^5$pa 이상의 압력 차이에 대하여 유량이 증가하지 않음을 확인하였다. 비응축 기체의 농도 변화에 의하여 벤튜리 내부에 발생하는 증기의 분포는 크게 달라지지만 유량은 같은 수준이 유지되어 비응축 기체의 농도가 1.5PPM에서 150PPM로 커질 경우, 유량이 약 2% 감소하였다. 이는 작동유체가 포함하고 있는 비응축 기체의 팽창과 생성된 증기가 압력 회복을 저해하는 영향이 유사하기 때문으로 풀이된다.