• 터널과지하공간
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• 제9권1호
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• pp.27-35
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• 1999

아치형 공동의 열원 경계에 대한 열전도 특성은 반무한평면이나 원형공동에 대한 열전도 특성과는 다른 양상을 나타낸다. 본 연구에서는 지하 냉동저장 pilot plant 의 운영을 통하여 계측된 저장공동 주위안반내 온도분포패턴의 분석을 통하여 아치형 공동의 열원 경계를 갖는 새로운 열전도식을 유도하였다. 계측된 암반온도 분포패턴은 선형적 변화와 로그함수적 변화의 중간적인 양상을 보였다. 열전파에 미치는 열물성 변수들의 영향도 분석 및 도출된 열전도식과 현장계측에 의한 암반온도 분포양상의 비교를 통하여 암반의 열물성을 추정하였다. 추정된 암반의 열전도도와 비열은 실내시험에 의한 무결 암석의 열물성과 비교해 20~25%의 차이를 보였다. 이는 암반내의 절리와 지하수의 영향에 기인한 것으로 판단되는데, 앞으로 현지암반에 대한 이들 영향요소의 조사와 열물성의 측정 및 비교분석을 통하여 정량적인 상관관계의 규명이 이루어져야 할 것이다.

• 대한환경공학회지
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• 제27권3호
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• pp.302-308
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• 2005

질산성 질소는 강변여과수에서 가장 흔히 발견되는 오염물질 중의 하나이다. 본 연구에서는 황을 이용한 독립영양탈질 공정을 강변여과수의 질산성 질소제거를 위한 반응벽체 기법에 도입하였다. 본 연구의 목적은 현장에서의 실제 강변여과수를 이용한 주 파일럿 실험을 통해 반응벽체 시스템에서 미생물 접종의 영향과 대체 알칼리도 공급원으로서 굴패각의 영향을 알아보고, 유량변화 및 체류시간 변화에 따른 질산성 질소 제거효율을 평가하는 것이다. 황과 석회석 또는 굴패각으로 구성된 준 파일럿 규모의 투수성 반응벽체(PRB) 6기를 경남 낙동강 유역 강변여과수 취수 현장에 설치하여 운전한 결과, 하수처리장의 혐기 소화 슬러지로부터 분리배양된 황탈질미생물 콘소시움 뿐만 아니라 굴패각의 자생미생물의 활성에 의해서 강변여과수의 질산성 질소가 제거됨을 확인하였고 석회석뿐만 아니라 굴패각도 시스템의 pH 조절을 위한 알칼리도 공급원으로 이용될 수 있음을 알 수 있었다. 그러나 알칼리도 공급원으로서 굴패각의 이용은 높은 황산이온의 농도와 고형물의 농도를 야기하였다. 80 cm의 반응벽체 두께에서, 유량을 66에서 132 mL/min까지 증가시킴으로써 체류시간을 15에서 7.5시간으로 감소시킴에 따라 질산성 질소 제거효율은 75에서 58%로 감소하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.555-560
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• 2002

The structure of Chosun-ilbo Boopyung factory was desined as exposed concrete. The self compacting concrete(non-vibrating concrete) must be applied to this case because the exposed concrete wall is very thin(200mm) and high(6m), Laboratory tests and semi mock-up test were performed for optimum mix design of the self compacting concrete. As a result, the optimum mixes were observed at the 3-component types(ope, fly-ash, slag powder) that Vp$\geq$0.175, Vw/Vp$\geq$0.95, W=170~175$kgf/m^3$ and B=500~540$kgf/m^3$ Based on this result. we make plan that the pilot productions of batcher plant, the full-scale mock up tests and site application.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.79-84
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• 2001

The effect of spray characteristics on desulfurization yield was evaluated by performing experiments with pilot spray drying sorber (SDS). Among the variables of operating conditions, the slurry-spraying conditions were chosen as major parameters; Stoichiometric ratio and Sauter mean diameter of slurry droplet were varied for the different gas temperatures and $SO_{2}$ concentrations in the inlet gas flow. From the experimental results, we proposed semi-empirical models of desulfurization yield for both Stoichiometric ratio and Sauter mean diameter of droplets. The optimal condition of spray can be determined based on these results, which might be applied to the design or scale-up of SDS systems.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.73-79
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• 2003

The characteristics of NOx emission in multi fuel/air staged combustor have been experimentally studied. The design concept of multi fuel/air staged combustor is creation of two separate flame, a primary flame is act as a pilot flame for the secondary combustion stage combustion zone, where most of fuel burns. Experiments were performed on a semi-industrial scale (thermal input 0.233 ㎿) in a laboratory furnace and Liquefied Petroleum Gas(LPG) was used as primary and secondary fuels. The study included parametric study to identify the optimum operating conditions which are primary/secondary fuel ratio, primary/secondary air ratio, primary swirl intensity and secondary swirl intensity for reducing NOx emission. The test demonstrated that NOx emission can be reduced by >70% in accordance with operating conditions.

• 대한기계학회논문집B
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• 제28권4호
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• pp.389-394
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• 2004

An experimental study on the NOx formation of LNG flame in fuel staged combustor has been studied. The design concept of multi fuel/air staged combustor is creation of two separate flame, a primary flame is a act as a pilot flame for the secondary combustion stage combustion zone, where most of fuel bums. Experiments were performed on a semi-industrial scale (thermal input 0.233 MW) in a laboratory furnace and Liquefied Natural Gas(LNG) was used as a primary and secondary fuels. This study included parametric study to identify the optimum operating conditions which are primary/secondary fuel ratio, and primary/secondary air ratio for reducing NOx emission with two types of nozzle. The test demonstrated that NOx emission can be reduced by >70% in accordance with operating conditions.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.163-171
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• 2001

The characteristics of NOx emission in multi fuel/air staged combustor have been experimentally studied. The design concept of multi fuel/air staged combustor is creation of two separate flame, a primary flame is act as a pilot Dame for the secondary combustion stage combustion zone, where most of fuel bums. Experiments were performed on a semi-industrial scale (thermal input 0.233 MW) in a laboratory furnace and Liquefied Petroleum Gas(LPG) was used as primary and secondary fuels. The study included parametric study to identify the optimum operating conditions which are primary/secondary fuel ratio, primary/secondary air ratio, primary swirl intensity and secondary swirl intensity for reducing NOx emission. The test demonstrated that NOx emission can be reduced by ${>}$70% in accordance with operating conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.161-166
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• 2001

An Experimental study on the NOx formation of LNG flame in fuel staged combustor has been studied. The design concept of multi fuel/air staged combustor is creation of two separate flame, a primary flame is act as a pilot flame for the secondary combustion stage combustion zone, where most of fuel burns. Experiments were performed on a semi-industrial scale (thermal input 0.233 MW) in a laboratory furnace and Liquefied Natural Gas(LNG) was used as primary and secondary fuels. The study included parametric study to identify the optimum operating conditions which are primary/secondary fuel ratio, and primary/secondary air ratio for reducing NOx emission with two types of nozzle. The test demonstrated that NOx emission can be reduced by >70% in accordance with operating conditions.

• ALGAE
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• 제39권2호
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• pp.109-127
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• 2024

High production and efficient harvesting of microalgae containing high omega-3 levels are critical concerns for industrial use. Aeration can elevate production of some microalgae by providing CO₂ and O₂. However, it may lower the production of others by generating shear stress, causing severe cell damage. The mixotrophic dinoflagellate Gymnodinium smaydae is a new, promising microalga for omega-3 fatty acid production owing to its high docosahexaenoic acid content, and determining optimal conditions and methods for high omega-3 fatty acid production and efficient harvest using G. smaydae is crucial for its commercial utilization. Therefore, to determine whether continuous aeration is required, we measured densities of G. smaydae and the dinoflagellate prey Heterocapsa rotundata in a 100-L semi-continuous cultivation system under no aeration and continuous aeration conditions daily for 9 days. Furthermore, to determine the optimal conditions for harvesting through centrifugation, different rotational speeds of the continuous centrifuge and different flow rates of the pump injecting G. smaydae + H. rotundata cells into the centrifuge were tested. Under continuous aeration, G. smaydae production gradually decreased; however, without aeration, the production remained stable. Harvesting efficiency and the dry weights of omega-3 fatty acids of G. smaydae + H. rotundata cells at a rotational speed of 16,000 rpm were significantly higher than those at 2,000-8,000 rpm. However, these parameters did not significantly differ at injection pump flow rates of 1.0-4.0 L min^-1. The results of the present study provide a basis for optimized production and harvest conditions for G. smaydae and other microalgae.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1173-1180
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• 2006

In this study, aluminum electrodes were put in marine clay which was taken from the south coast in Korea to increase the undrained shear strength by inducing the densification and cementation between clay particles and precipitates which were developed by electric decomposition in an electrode. To raise the cementation rate and reduce treatment time, high electric current (2.5A) was applied in each electrode at a semi-pilot scale soil box with marine clay. After the tests, the undrained shear strength was measured at designated points using a static cone penetration test device and sampling was conducted simultaneously in order to measure water content, pH and electric conductivity which would be the key for configuring the cementation effects indirectly. In the results of electric decomposition in aluminum electrode, the measured shear strength was increased considerably compared to the initial shear strength because of the cementation effect between iron ions and soil particles.