Enhancement of Outdoor Mass Production of Algal Biomass by Microdroplet-based Screening of Fast-growing Microalgae under Fluctuating Light

Young Joon SUNG,Sang Jun SIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Microalgae, considered as a fascinating bio-platform for CO₂ capture, can be used as cell factories for sustainable production of value-added products. To increase the feasibility of the microalgae process, outdoor mass cultivation has been conducted but the variable sunlight can be the major obstacle to achieving this goal. Here, we cultivated Chlamydomonas reinhardtii mutant cells in microfluidic-based microdroplet photobioreactor to effectively deliver simulated sunlight conditions to individual cells. For screening of fast-growing mutants, gel microdroplets were separated through the density gradient centrifugation. We selected a mutant with mutations in the SNF2 (sucrose non-fermentable 2) which showed 1.85-fold increase in cell growth with enhanced photosynthetic efficiency in fluctuating light. After field culture using natural sunlight and industrial CO₂ near the power plant, the mutant exhibited improvement of biomass productivity and calorific value, a crucial fuel performance, by 34.38% and 16.82%, respectively. This approach can maximize the outdoor productivity by boosting sunlight utilization of the photosynthetic microorganisms.

Droplet-based microfluidic screening of fast-growing microalgal strains under fluctuating light enhances outdoor mass production of algal biomass

성영준,심상준 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.0

An experimental study on the organic Rankine cycle to determine as to how efficiently utilize fluctuating thermal energy

Cho, Soo-Yong,Cho, Chong-Hyun Elsevier 2015 RENEWABLE ENERGY Vol.80 No.-

<P><B>Abstract</B></P> <P>Thermal properties of the available energy such as maximum temperature and thermal energy capacity are greatly influenced to the design of energy conversion system like the organic Rankine cycle (ORC). Useful thermal energy can be obtained from: waste heat energy, geothermal energy, solar heat energy, biomass energy, and so on. However, these cannot usually be supplied at constant levels. Hence, the temperature and flowrate of the thermal energy can vary while the ORC is working. In order to efficiently utilize such fluctuating thermal energy, an experimental study was conducted while adjusting the mass flowrate and the temperature of the working fluid. Three supersonic nozzles and an impulse type turbine were applied. The supersonic nozzle was adopted to increase the spouting velocity for efficient operation of the impulse turbine. The nozzle was designed to reach a velocity of Mach 1.6 at the nozzle exit, and three nozzles were used to control the mass flowrate in this experiment. The experimental results were compared with the predicted results obtained by the cycle analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An experiment study was conducted using a turbo expander to efficiently utilize fluctuating thermal energy on the ORC. </LI> <LI> Operating conditions were investigated for various input conditions using the R-245fa working fluid. </LI> <LI> Supersonic nozzles were applied to adjust the mass flow rate as well as to increase the spouting velocity in the turbine. </LI> <LI> Measured the performance of the ORC system, and the experimental results were compared with the predicted results. </LI> </UL> </P>

유동층에서 유기성 오니의 마모 특성

서원태,장준호,장윤영,장현태 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.9

Combustion of a mixture of fossil fuel and organic sludge is the most efficient method for the treatment of combustible wastes in order to reduce carbon dioxide generation due to the reduction of fossil fuel use. The high heat and mass transfer efficiency from fluidized bed combustion allows utilization of various fuels, in which the ash of solid fuel is discharged as bottom ash and fly ash. This study analyzes the discharge characteristics of organic sludge ash in a fluidized bed. Therefore, attrition and elutriation characteristics of organic sludge ash were examined by using the ASTM D5757-95 method and 1½-inch and four-inch fluidized beds, respectively. The ASTM D5757-95 method measures particle attrition via air jet. The particle size range was 200 μm and under. For particle sizes of 200㎛ and over, attrition characteristics were measured in a 1½-inch fluidized bed with only organic sludge and in a four-inch fluidized bed with bed material sand and organic sludge. The pressure fluctuation properties were measured in a four-inch fluidized bed by four pressure sensors installed at intervals of 0.03m above the distributor plate. Pressure fluctuation properties, such as mean pressure and standard deviation of the pressure fluctuations were calculated. From the pressure fluctuation properties, it was possible to predict particle attrition and elutriation of organic sludge in the fluidized beds. The organic sludge was fed into the fluidized bed for attrition and elutriation from friction and collision between particles and the wall and the jet of the supply air. It was found that suspended particles carried the combustion gas. 화석연료 사용 감소에 따른 이산화탄소 발생 저감을 위한 가연성 폐기물의 처리 방법으로 혼합연소가 가장 효율적 방법이다. 유동층연소로는 열 및 물질전달 효율이 높으므로 다양한 연료 사용이 가능하고 높은 전열 강도를 지니고있다. 유동층연소로는 투입된 연료의 회분 성분이 바닥재와 비산재로 배출된다. 본 연구에서는 유동층에 공급된 유기성오니 회분의 배출 특성을 규명하고자 연구를 수행하였다. 따라서 유기성 오니 회분의 마모 및 비산유출 특성을 ASTM D5757-95 방법과 1½, 4인치 유동층에서 각각 수행하였다. ASTM D5757-95는 200㎛ 이하 입자의 마모를 연구하였으며, 200㎛ 이상의 입자는 1½인치 유동층에서는 유기성 오니만을 충전한 상태에서의 마모 특성, 4인치 유동층에서는층물질 모래와 유기성 오니를 충전하여 마모 특성을 측정하였다. 또한 내경 4인치 유동층에서는 유동층 분산판으로부터0.03m 간격으로 4개의 압력센서를 설치하여 유동층의 압력요동 특성을 측정하였다. 측정된 압력값으로부터 압력요동특성치인 평균압력과 압력요동의 표준편차를 계산하였다. 압력요동특성치로써 유동층에서 유기성 오니의 마모 유출특성을 관측할 수 있는 방법을 제시할 수 있었다. 유동층에 공급된 유기성 오니는 입자간 및 기벽과의 마찰과 공급공기의jet에 의하여 마모 비산되어 연소가스에 동반되어 유출되는 것을 알 수 있었다.

광릉 원두부 소유역에서의 우기 중 지하수 함양률 평가

최인혁 ( In Hyuk Choi ),우남칠 ( Nam Chil Woo ),김수진 ( Su Jin Kim ),문상기 ( Sang Ki Moon ),김준 ( Joon Kim ) 한국농림기상학회 2007 한국농림기상학회지 Vol.9 No.2

광릉 슈퍼사이트 내 원두부 소유역에서 지하수위변동법, 이온수지법, 수문곡선분리법 등 세가지 방법을 적용하여 지하수 함양률을 평가하고, 방법별 결과들을 비교하였다. 이를 위한 자료는 우기에 해당하는 2005년 6월부터 9월까지 취득하였다. 두 가지 다른 지하수위변동 법으로는 각각 25.9%, 23.6%의 지하수 함양률이 산출되었고, 염소를 이용한 이온수지법은 평균 13.4%의 함양률이, 그리고 6개의 수문곡선과 염소 이온자료를 이용한 기저유출 분리법은 평균 14.0%의 순기저유출률이 산출되었다. 장기적으로 지하수 저장량의 변화가 없는 정류상태를 가정하는 이온수지법과 수문곡선 분리법에서 산출된 지하수 함양률이 지하수 함양으로 인해 지하수위의 상승과 저장량의 변화를 고려하는 지하수위변동법에서 산출된 지하수 함양률보다 작게 산정되었다. 따라서 수문순환의 동력학적 특성을 이해하는 측면에서는, 지하수위변동법에 의한 지하수 함양률 평가가 다른 방법들보다 우월함을 보인다. Groundwater recharge rates were estimated and compared in a headwater catchment at the Gwangneung Supersite using three different methods: water-table fluctuation (WTF), mass balance, and hydrograph separation techniques. Data were obtained during the rainy season from June to September 2005. Two different WTF methods estimated the groundwater recharge rate as 25.9% and 23.6%. The mass balance calculation of chloride ions indicated recharge rates of 13.4% on average. Baseflow separation using chloride ion as a tracer from six storm hydrographs produced a 14.0% net baseflow rate on average. Because of the implicit assumption of a long-term steady state without storage change, recharge rates calculated by mass balance and hydrograph separation were smaller than those done with WTF methods, which include the amount of increased storage due to the water-level rise. Subsequently, the WTF method is superior to others in the estimation of groundwater recharge rate to comprehend the dynamic characteristics of the hydrologic cycle.

RANGE EXTENDER MODULE TRANSMISSION TOPOLOGY STUDY

Konrad Herold,Marius Böhmer,Rene Savelsberg,Alexander Müller,Jan Schröter,Jan Karthaus,Un-Jae Seo,Georg Jacbos,Kay Hameyer,Jakob Andert 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.5

Range extender modules are one option to compensate for short drive ranges of electric vehicles. The close interaction of combustion engine and generator poses new challenges in development. A key requirement for range extender systems is to be light and virtually imperceptible in operation. High-speed electrical machines aim at increasing power density. However, their introduction in a range extender requires a gearbox. The combustion engine torque fluctuations can lead to rattle in the gearbox. The rattle can be overcome by a dual mass flywheel. An interdisciplinary model is developed and used to analyse three different range extender systems: one with a low speed generator without gearbox, one with a high-speed generator, and one with a high-speed generator and a dual mass flywheel. The efficiency was found to be higher for the system with a low speed generator, whereas the power density and the costs are beneficial for the high-speed concept. A dual mass flywheel eliminates the changes of torque direction in the gearbox. It reduces the speed fluctuations of the gearbox and generator by over 90 % compared to the low speed setup. But it increases rolling moment and subsequently chassis excitation compared to a setup with only a gearbox.

인젝터 동특성 연구를 위한 유량변동측정 정량화

길태옥 ( Tae Ock Khil ),김성혁 ( Sung Hyuk Kim ),조성호 ( Seong Ho Cho ),윤영빈 ( Young Bin Yoon ) 한국액체미립화학회 2007 한국액체미립화학회 학술강연회 논문집 Vol.2007 No.-

합성 성페로몬 대량유살 트랩을 이용한 파밤나방의 발생소장, 발생량 및 방제효과

김규진,박종대,최덕수 한국응용곤충학회 1995 한국응용곤충학회지 Vol.34 No.2

파밤나방의 합성 성페로몬 대량유살 트랩을 이용하여 1992년부터 1994년까지 3년간 남부지방을 중심으로 발생소장, 발생량 및 방제 가능성을 검토한 결과 파밤나방 서충은 4월부터 트랩에 유인되기 시작하였으며 6월하순까지는 발생량이 극히 미미하였으나 7월상순부터 발생량이 급격히 증가하여 11월 상순까지 유인되었고 발생최성기느는 7월중순, 8월상순, 9월상순이었다. 년차별 발생량 및 발생면적은 전남지방의 경우 1992년은 1,630마리, 3,979.5ha, 1993년은 218마리, 283.0ha, 1994년은 1,630마리, 4,262.5ha로 그해의 기상에 따라 변이가 컸는데 특히 1993년의 저온과 8월중의 집중 강우는 본종의 발육과 정착에 영향을 끼쳐 발생량과 피해면적이 극히 적었다. 합성 성페로몬 트랩과 유아등에 의한 유인량은 1993년, 1994년 모두 페로몬 트랩이 1.5배, 2.3배 많았다. 비닐하우스 내에서 대량유살 트랩에 의한 방제 가능성은 330당 10개이상 처리한 경우에 효과적이었다. This study was carried out to investigate the effect of mass trapping with synthetic sex pheromone on seasonal occurrence of, the Beet amyworm (BAW) Spodoptera exigua, and on suppress of their density in Chonnam province from 1992 to 1994. Adult males of BAW were colllected by the trap from early through early November. The numbers began to increase abruptly from early July, and forming three peaks on mid July, early August and early September. Yearly occurrence and the area damaged by the BAW varied in relation to weather condition. Especially, low temperature and heavy rainfall in August 1993 seems to have affected to reduce the BAW population. The pheromone trap attracted higher numbers (1.5~2.3 times) of BAW adult than ordinary light rap. And the BAW population in vinyl hose was noticeably reduced when more than 10 pheromone traps were operated per 330 of vinyl house.

Effect of Ga alloying on thermoelectric properties of InSb

Zhengliang Du,Xiaolu Chen,Junhao Zhu,Jiaolin Cui 한국물리학회 2018 Current Applied Physics Vol.18 No.8

As a potential thermoelectric (TE) material, the high lattice thermal conductivity and relatively low weighted mobility severely limit TE property optimization of InSb binary compound. In this paper, we substituted In of InSb with Ga and systematically investigated the effect of Ga alloying on the Seebeck coefficient, electrical conductivity and lattice thermal conductivity of InSb between 300 K and 770 K. We found that Ga alloying simultaneously reduced the lattice thermal conductivity and optimized the weighted mobility of InSb. The lattice thermal conductivity has been analyzed using Abeles model to gain more insight on the roles of Ga in In1-xGaxSb (x=0, 0.1, 0.15, 0.2) solid solution. The synergetic effect of Ga alloying on the electron and phonon transport leads to a marked enhancement in TE potential of InSb. The dimensionless figures of merit of InSb and In0.8Ga0.2Sb reach, respectively, 0.54 and 0.52 at 770 K.