An objective classification of commercial thickened foods was studied for Korean elderly people with swallowing difficulty as based on rheological properties. A total of 16 commercial products (grain porridges, vegetable porridges, meat porridges, fish and shellfishes porridges, nut porridges) were measured using a stress-controlled rheometer with stainless steel plate-plate geometry and building material cell. Joint consideration has been made of viscous behavior (flow and thixotropy) and viscoelastic behavior (oscillatory testing). Rheological measurements were fitted to different rheological and empirical mathematical models, and a total of 11 parameters were generated. Based on these parameters and the use of fuzzy clustering and the c-means method, an objective classification of all the products was obtained. 16 commercial products were divided to 3 clusters. Each class has been defined from the parameters of the centroids generated by the classification method used - thus allowing us to know the common rheological characteristics of any of the products belonging to a given class. The results of this classification encourage further to develop of the new products for Korean elderly people.

Polyphenylene sulfide(PPS) is a hydrocarbon polymer which has resistance to heat, chemicals and generality due to its low cost. To produce cationic exchange polymer, PPS was blended with sulfonation process and Polyvinylidenedifluoride(PVdF) was also applied for membrane-flexibility. After production of sulfonated-PPS (sPPS)/PVdf blend membrane, membrane property evaluation is concomitant. Water uptake and Dimensional change were highly enhanced by the incorporation of PVdF in blend membrane. Also stability of sPPS/PVdF blend membrane in VO2+ solution was highly improved. When the amount of PVdF is increasing, however, proton conductivity shows a slightly downward tendency. Consequently, the optimization of PVdF Content in sPPS/PVdf blend membrane is an important factor for the realization of VRFB system.

Recently, the most commonly used membrane in vanadium redox flow battery (VRFB) is hydrocarbon-based cation exchange membrane. However, hydrophilic blocks or hydrophilic moieties have been considered as the main reason on degradation of hydrocarbon-based ionomers, while the significance of hydrophobic moiety has been neglected in ionomers. Herein, the poly(p-phenylene)s-based cation conducting polymeric membrane materials with different hydrophobic block structures were successfully synthesized by Ni(0)-catalyzed coupling polymerization for investigating the effect of the hydrophobic block structure on durability of membrane in VRFB.

The damping effects on stabilities of a simply supported pipe conveying fluid is investigated using the complexification-averaging method. The flow is assumed to vary harmonically about a mean speed. Unstable conditions of a piping system included with the viscous and material damping are analytically obtained for primary, secondary and combination parametric resonances. The primary and secondary resonances occur when the frequency of flow fluctuation is close to one and two times the natural frequency. And when this frequency is close to the sum of any two natural frequencies, combination resonances occur. The effects of damping parameters on the regions of three parametric resonances are discussed.

It is necessary to develop a device for the design of wet scrubber with a more efficient deodorization performance in order to enhance the odor reducing effect of the wet scrubber. Therefore in this study, the superiority of the new wet scrubber with the centrifugal separation function different from the conventional wet scrubber was analyzed by the computational fluid dynamics. From CFD analysis, the pressure and velocity distribution, the peak vorticity, the retention time and the flow uniformity were calculated and compared with the performance characteristics of the centrifugal separator. As the results of CFD analysis, the peak vorticity and retention time of the gas flow were increased about 22% and the flow uniformity was improved about 7.2% by the centrifugal separator. Therefore the centrifugal separator in the wet scrubber will improve the deodorizing effect and the cleaning condition of the gas.

바나듐 산화환원 흐름 전지에 핵심적으로 사용되는 이온교환막은 일반적으로 양이온교환막을 사용하고 있으나 co-ion인 바나듐 이온의 투과에 의한 장기적 성능 저하 문제를 해결하기 어렵다. 따라서 본 연구에서는 바나듐 투과도 및 장 기 운전 안정성의 특성을 파악하기 위해 세 가지 다른 관능기를 보유한 음이온교환막을 제조하였다. 기저막으로는 다공성 폴 리에틸렌 필름에 benzyl chloride (VBC)과 divinylbenzene (DVB)을 충진 및 가교 중합하여 제조한 후, 세 가지 다른 아민 관 능기를 각각 도입하였다. 제조된 음이온교환막들에 대해 바나듐 이온 투과 정도 및 장기 운전 안정성을 관찰한 결과 triethylamine을 관능기로 적용한 음이온교환막에서 높은 에너지효율을 유지하면서도 가장 장기적 운전 안정성을 확보할 수 있었다.

본 연구에서는 얇은 폴리에틸렌 계 다공성 필름(두께 = 25 μm)에 이오노머를 충진시킨 세공충진 이온교환막을 개발하였으며 이를 적용한 전 바나듐 레독스 흐름전지의 충방전 특성을 고찰하였다. 특히 분자 크기가 다른 가교제를 혼합함 으로써 이온교환막의 가교도 및 자유체적을 적절히 제어하여 저저항 및 저 바나듐 투과도를 나타내는 이온교환막을 제조하 고자 하였다. 실험 결과, 제조된 세공충진 이온교환막은 상용막 대비하여 동등 수준의 우수한 전기화학적 특성을 나타내었다. 또한 바나듐 이온 투과도 및 전 바나듐 레독스 흐름전지 성능 평가 실험을 통해 얇은 막 두께에도 불구하고 상용막 대비하여 낮은 바나듐 이온 투과도와 높은 충방전 효율을 나타냄을 확인하였다.

Spermatozoa viability can be assessed by microscopy, flow cytometry, and other methods using fluorescent stain. Flow cytometry can be used to examine the morphological and functional characteristics of spermatozoa in a short time. The purpose of this study was to compare the viability of cryopreserved spermatozoa in Jeju black cattle by two dual fluorescent stain methods. Semen of Jeju black cattle raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA were collected with artificial vaginal technique. Sperm was diluted with Triladyl®-egg yolk diluent and then was performed cryopreservation.There was no significant difference in viability of spermatozoa according to the two dual fluorescent stain methods. However, when the distribution of spermatozoa according to the staining method was compared, the spermatozoa group stained with 6-CFDA/PI was more clearly distinguished than the spermatozoa group stained with calcein AM/PI.

본 연구는 경주 중·저준위처분장 2단계 표층처분시설의 폐쇄 후 안전성에 대한 불확실성을 예측·평가하기 위하여 수행되 었다. 다중덮개와 처분고의 건전/열화를 고려한 총4가지의 시나리오를 도출하여 강우침투 시 예상되는 처분시설 내부의 유 체 이동을 모사하였다. 강우 조건은 총 30년(1985~2014) 간의 월평균 데이터를 적용하였으며, 시뮬레이션 기간은 제도적 관 리기간인 300년으로 설정하였다. 처분덮개와 처분고 콘크리트 모두 건전성을 유지하는 조건의 기본 시나리오 평가 결과, 처 분시설 내부의 처분고를 완전히 포화시키지 못하는 것을 확인할 수 있었다. 다중 덮개층을 구성하는 8개 층의 각 매질의 모 세관 압력과 투과도 차이로 인하여 다중 덮개층이 효과적으로 차수·배수 역할을 하는 것으로 나타났다.

In this study, the heat flow characteristics of wave heat exchanger was investigated by being applied to the white smoke reduction system. Through numerical analysis, the heat transfer and flow characteristics of the wave heat exchanger with the change of inlet condition of air-side and water-side were analyzed. To investigate the temperature, the absolute humidity, heat transfer rate, pressure drop and turbulence characteristics of the wave heat exchanger, the simulation analysis was conducted by using the commercial computational fluid dynamics software (Solidworks Flow Simulation) under uniform flow conditions. As the inflow rate of air decreased and the inflow temperature of water increased, the heat transfer coefficient of the wave heat exchanger decreased. When the experimental conditions of water-side were the same, the air outlet temperature and absolute humidity of the wave heat exchanger increased with increasing inflow rate of air. To reduce the white smoke, the air outlet temperature and absolute humidity of the wave heat exchanger must be reduced. Therefore, the lower the air velocity and the water inflow temperature into the wave heat exchanger, the more effective it is.

PURPOSES :In this paper, the flow of construction material was simulated using computational fluid dynamics in a 2D axisymmetric condition to evaluate the effect of initial or varying material properties on the final shape of a specimen.METHODS :The CFD model was verified by using a well-known analytical solution for a given test condition followed by performing a sensitivity analysis to evaluate the effect of material properties on the final shape of material. Varying dynamic viscosity and yield stress were also considered.RESULTS :The CFD model in a 2D axisymmetric condition agreed with the analytical solution for most yield stress conditions. Minor disagreements observed at high yield stress conditions indicate improper application of the pure shear assumption for the given material behavior. It was also observed that the variation of yield stress and dynamic viscosity during curing had a meaningful effect on the final shape of the specimen.CONCLUSIONS :It is concluded that CFD modeling in a 2D axisymmetric condition is good enough to evaluate fluidal characteristics of material. The model is able to consider varying yield stress and viscosity during curing. The 3D CFD-DEM coupled model may be required to consider the interaction of aggregates in fluid.

Marine structures developed for marine industry and resource manifests different fluid characteristics. As such, the changes in the location, shape and size of these structures affect the fluid flow. Specifically, this wake flow caused by the structures result in environmental damage and topographical change. but on the other hand, protects harbor facility and environment. This study was conducted by changing the position of vertical plate in horizontal and vertical direction and experimented the variation of wake flow by PIV. This experiment confirmed the wake flow reduction by the changes of gab in horizontal and vertical direction. Particularly, the experiment showed that changes of gab in horizontal and vertical direction resulted in an increased u-velocity fields in the back of structure for larger horizontal gab.

본 연구에서는 배가스 내 존재하는 오염물질인 NO의 처리효율을 증대시키기 위하여 NO 산화 공정을 연구하였으며, 강력한 산화력의 건식산화제를 제조하는 방법으로 H2O2 촉매분해가 도입되었다. H2O2 분해공정 상에서 적용 가능한 K-Mn/Fe2O3 불균일계 촉매가 제조되었으며, 이들이 가지는 물리화학 적 특성이 H2O2 분해반응에 미치는 영향이 조사되었다. 제조된 건식산화제는 NO가 포함된 모사 배가스를 처리하기 위한 NO 산화공정에 적용되었으며, 다양한 모사 배가스의 유량(5, 10, 20 L/min)에서 약 100% 가까운 NO 전환율을 확인 하였다.

본 연구에서는 TiO2 nanotube 광촉매의 고도산화처리능을 비교하기 위해서 OH 라디칼 생성 력을 평가하고자 하였다. 자외선 조사에 따른 Probe compound인 4-Chlorobenzoic acid (pCBA)의 농 도 감소에 따라 OH radical 생성량을 산정하는 방법으로 광촉매 효율을 평가하였는데, TiO2 nanotube 표면에서의 전자의 흐름을 원활하게 하기 위하여 전기적 에너지를 주었을 시 광촉매 효율의 증가 가능 성 또한 확인하고자 자외선 조사 시 전류밀도를 인가하는 방법으로 실험을 진행하였다. 실험에 사용된 TiO2 nanotube는 전극효과를 부여하기 위해 양극산화법으로 티타늄판을 이용하여 제조하였으며, pCBA 용액에는 전도도를 부여하기 위하여 NaCl을 첨가하여 전해질로 사용하였다. 정전류 정전압 조건하에서 자외선조사 실험을 진행하였으며, 전류가 흐르는 광촉매에 자외선 조사 시 OH 라디칼 생성량은 광촉매 없이 자외선만 조사하였을 때에 비해 약 5.6배, TiO2 광촉매와 함께 자외선을 조사하였을 보다 약 2.2 배 증가하였다. 결과적으로 광촉매반응에 전기적 에너지를 부여하였을 시 시너지효과를 가져올 수 있는 가능성을 확인할 수 있었다.