• 한국양식학회지
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• 제16권4호
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• pp.216-222
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• 2003

In a simulated seawater aquaculture system, effects of different operating factors like the superficial air velocity (SAY), hydraulic residence time (HRT), protein concentration and foam overflow height on the removal of total suspended solids (TSS) by a foam fractionator, with 20 cm diameter and 120 cm height, were investigated. This experiment was performed on batch and consecutive modes for different combinations of the tested factors, using synthetic wastewater. In 5 consecutive trials, TSS concentration in culture tank water decreased faster, when the foam fractionator was operated at higher SAV and lower HRT. In batch trials, with increasing SAV, TSS removal rate increased, but decreased with increasing HRT. Higher protein concentration in the bulk solution resulted in higher TSS removal rate. TSS concentration in the collected foam condensates increased but the foam overflow rate decreased with increasing foam overflow height. Foam fractionation was effective for removing TSS in seawater aquaculture systems and its performance largely depended on the operating parameters, especially superficial air velocity.

• 설비공학논문집
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• 제3권4호
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• pp.215-221
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• 1991

Laminar film condensation of a saturated vapor in forced flow over a flat plate is analyzed by using integral method. Laminar condensate film is so thin that the inertia and thermal convection terms in liquid flow can be neglected. Approximate solutions for water are presented and well agreed with the similarity solutions over the wide range of physical parameter, Cp1(Ts-Tw)/Pr.hfg. For the strong condensation case, it is found that magnitude of the interfacial shear stress at the liquid-vapor interphase boundary is approximately equal to the momentum transferred by condensation, i.e., ${\tau}_i{\simeq}\dot{m}(U_O-U_i)$.

• Corrosion Science and Technology
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• 제16권4호
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• pp.161-166
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• 2017

The qualitative composition of active components of the corrosion inhibitor CGW-85567 was studied. It was found that С18:2 and С18:1 imidazolines and the corresponding imidazolin-amides are the major components. The HPLC/MS technique was developed for their determination in the water solutions of monoethylene glycol (MEG). Industrial application of the inhibitor showed that MEG solution retained high concentration of the inhibitor for a long time after ceasing its addition into pipelines. Low values of the partition coefficients (0.010-0.014) of imidazolines in the system "water solution of MEG (concentration of MEG 62-85% v/v) - gas condensate" have allowed to pass on from the technology of continuous pumping of the inhibitor into protected pipelines to the periodic dosing technology. Taking into account a long time of circulation in the system and high temperatures during MEG regeneration process possible degradation products of the inhibitor were studied. N, N-dimethyl-dodecanamine-1, and N, N-dimethyl-tetradecanamine-1 were identified as major degradation products of the corrosion inhibitor CGW-85567.

• Korean Chemical Engineering Research
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• 제55권4호
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• pp.478-482
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• 2017

고분자 전해질 연료전지의 구동과정 중 습도제어는 매우 중요한 제어 조건이다. 물 관리 측면에서는 저가습 조건이 유리하고, 배출수 활용 및 에너지 효율면에서는 고가습이 유리하다. 본 연구에서는 배출수 활용면에서 저가습과 고가습 구동 과정에서 배출수의 특성에 대해서 연구하였다. 배출수의 불순물은 막과 전극의 열화 과정에서 발생하는 것이므로 저가습과 고가습 조건에서 막전극합체(MEA)열화에 대해서도 연구하였다. 연료극 0% RH의 저가습 조건에서 라디칼 발생속도가 커 고분자 막 열화의 주요 원인임을 보였다. 양쪽 극 모두 고가습(RH 100%) 0.6 V에서 불소 이온 농도 약 20 ppb로 낮은 농도를 나타내서, 수전해 원료수로 사용하기에 충분하였다. 고가습 조건에서 배출한 응축수에서 0.2 ppb 이하의 매우 낮은 농도의 백금이 검출되었다.

• 콘크리트학회지
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• 제7권3호
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• pp.156-163
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• 1995

앞 선 연구에서는 스티렌과 무수말레인산으로부터 스티렌-무수말레인산 공중합체(SMA)를 합성하고 이들을 황산화하여 수용성의 SMA를 제조하였다. 본 연구에서는 이들 카르본산계 공중합체를 첨가한 시멘트 모르타르의 플로우 및 경화시멘트 모르타르의 강도를 조사하여 고성능감수제로서의 성능을 평가하였다. 플로우 실험 결과 황산화 SMA(SSMA)를 첨가한 시멘트 모르타르의 플로우는 아미노페놀이 치환된 황산화 SMA(SmSMA)를 첨가한 경우보다 더 큰 값을 나타내었다. 또한 공중합체를 첨가한 시멘트 모르타르의 플로우 유지율은 기존의 나프탈렌계(NSC)를 첨가한 경우보다 우수하게 나타났다. 시멘트 모르타르에 SMA와 SmSMA를 시멘트 중량에 대해 0.5% 첨가하여 제조한 경화 시멘트 모르타르의 28일 압축강도를 조사하였다. 그 결과 SSMA 및 SmSMA를 첨가한 경우 plain 보다 각각 31%와 13%의 강도 증가를 나타내었다. 이상의 결과로부터, 본 연구에서 사용한 SSMA 및 SmSMA의 카르본산계 공중합체는콘크리트용 고성능감수제로서 크게 기대되어진다.

• 한국전산유체공학회지
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• 제17권4호
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• pp.93-102
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• 2012

Once the condensation of water vapor in moist air around a thin airfoil occurs, liquid droplets nucleate. The condensation process releases heat to the surrounding gaseous components of moist air and significantly affects their thermodynamic and flow properties. As a results, variations in the aerodynamic performance of airfoils can be found. In the present work, the effects of upstream Mach number and thickness ratio of airfoil on the transonic flow of moist air around a thin airfoil are investigated by numerical analysis. The results shows that a significant condensation occurs as the upstream Mach number is increased at the fixed thickness ratio of airfoil($\epsilon$=0.12) and as the thickness ratio of airfoil is increased at the fixed upstream Mach number($M_{\infty}$=0.80). The condensate mass fraction is also increased and dispersed widely around an airfoil as the upstream Mach number and thickness ratio of airfoil are increased. The position of shock wave for moist air flow move toward the leading edge of airfoil when it is compared with the position of shock wave for dry air.

• 한국수산과학회지
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• 제11권4호
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• pp.183-188
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• 1978

피등어꼴뚜기를 가열가공할 때 발생하는 취기를 제거할 목적으로 취기성분을 gas chromatography로 공석한 것을 단보로서 요약하면 다음과 같다. 1. 피등어꼴뚜기 취기성분 추출에는 methanol이 가장 적합하였다. 2. 빙수trap에서 25개 peak, dry ice-acetone trap에서 32개 peak가 검출되었고, 그 중 acetic acid, butyric acid, iso-valeric acid, valeric acid, caproic acid 등 5성분을 동정하였다. 3. 액체질소 trap의 head space vapor에서 11개 peak가 검출되었고, 그 중 mothylamine, trimethylamine, dimethylamine, ethylamine, isopropylamine등 5성분을 동정하였다.

• Ocean and Polar Research
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• 제25권3호
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• pp.269-275
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• 2003

Effects of different operating factors including superficial air velocity (SAV), hydraulic residence time (HRT), protein concentration, and foam overflow height on protein removal by a foam fractionator in simulated seawater aquaculture system were investigated. This experiment was conducted on batch and consecutive modes at different combinations of the affecting factors. The foam fractionator had a diameter of 20cm and a height of 120cm and the experiment was conducted with synthetic wastewater. In 5 consecutive trials, protein concentrations in culture tank water decreased faster when the foam fractionator was operated at higher SAVs and lower HRTs. In batch trials, protein removal rates increased with an increase in SAV but decreased with an increase in URT. Higher protein concentrations in the bulk solution resulted in higher protein removal rates. Protein concentrations in the collected foam condensates increased but the foam overflow rates decreased with the increase of foam overflow heights. The results of this experiment indicate that foam fractionation would be an effective way for protein removal in seawater aquaculture systems and the performance of the foam fractionator depends largely on the operating parameters, especially SAV.

• 한국유체기계학회 논문집
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• 제19권2호
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• pp.49-54
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• 2016

A conceptual study of an air-cooled heat exchanger is conducted to achieve the long-term passive cooling of an integral reactor. A newly designed air-cooled heat exchanger is introduced in the present study and preliminary thermal sizing is demonstrated. This study mainly focuses on feasibility of an innovative air-cooled heat exchanger to extend the cooling period of the passive residual heat removal system(PRHRS) only in passive manners. A vertical shell-and-tube air-cooled heat exchanger is installed at the top of the emergency cooldown tank(ECT) to collect evaporated steam into condensate, which enables water inventory of the ECT to be kept. Finally, thermal sizing of an air-cooled heat exchanger is presented. The length and the number of tubes required, and also the height of a stack are calculated to remove the designated heat duty. The present study will contribute to an enhancement of the passive safety system of an integral reactor.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.641-646
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• 1998

In order to enhance the dynamic and interactive simulation capability of a system thermal hydraulic code for nuclear power plant, applicability of flow network models in SINDA/FLUIN $T^{™}$ has been tested by modeling feedwater system and coupling to DSNP which is one of a system thermal hydraulic simulation code for a pressurized heavy water reactor. The feedwater system is selected since it is one of the most important balance of plant systems with a potential to greatly affect the behavior of nuclear steam supply system. The flow network model of this feedwater system consists of condenser, condensate pumps, low and high pressure heaters, deaerator, feedwater pumps, and control valves. This complicated flow network is modeled and coupled to DSNP and it is tested for several normal and abnormal transient conditions such turbine load maneuvering, turbine trip, and loss of class IV power. The results show reasonable behavior of the coupled code and also gives a good dynamic and interactive simulation capabilities for the several mild transient conditions. It has been found that coupling system thermal hydraulic code with a flow network code is a proper way of upgrading simulation capability of DSNP to mature nuclear plant analyzer (NPA).