• Journal of the Korean Applied Science and Technology
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• v.18 no.1
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• pp.1-6
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• 2001

Theoretical model has been studied for the transport phenomena of molecules in the system where an electric potential is applied to the system in the axial direction. The effect of electrophoretic convection in the polymeric media is significantly contributed to separate large ionic-molecules because the conformation of large ionic-molecule quickly orients in the field direction. The dependence of the transport in the polymeric media upon field intensity and molecular size aids in understanding the transport of large ionic-molecule in the system, since the convective velocity of large ionic-molecule is accelerated inside a porous material. The transport distance of individual large ionic-molecule can be predicted using the reptation theories.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.648-654
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• 2005

The performance prediction of a planar-type solid oxide fuel ceil is conducted by a computational analysis. The transport processes are formulated with the help of a simplified treatment of heat generation by the electrochemical reaction. From the result of the computational analysis, it is shown that the electrochemical reaction is closely related to the transport phenomena inside a solid oxide fuel cell. Transport phenomena including heat and mass transfer have influence on the distribution of local current density and as a result, on the performance characteristics of the fuel cell. Computational analysis is also extended to the parametric study to investigate the performance behavior of the fuel cell with different amount of supplied fuel flow rates. It is also demonstrated that the mathematical formulation and computational procedures proposed in this study can be applied to prove the importance of the specific TPB(Three-Phase-Boundary) area in the manufacturing process of electrodes in a solid oxide fuel cell.

• Journal of Pharmaceutical Investigation
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• v.22 no.4
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• pp.289-300
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• 1992

The counter-transport phenomena in the hepatic transport of 1-anilino-8-naphthalene sulfonate (ANS) were kinetically investigated by analyzing the plasma disappearance-time profiles and the transport into the isolated hepatocytes. In vivo "counter transport phenomena" were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The condition that the mobility of carrier-ligand complex is greater than that of free carrier is not essential for the occurrence of counter-transport phenomenon. To examine the inhibitory effects on the initial uptake of a ligand by the liver, it is necessary to judge whether the true counter-transport mechanism (trans-stimulation) is working or not. The initial plasma disappearance curves of ANS were then kinetically analyzed based on a two-compartment model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). No effects on the initial plasma disappearance rates of ANS were observed after preloading of bromophenol blue (BPB) or rose bengal (RB) in the liver. Inhibitory effect of BPB or RB on the initial uptake (or efflux) rates of ANS by the isolated hepatocytes were not observed, suggesting that the true counter transport mechanism is not working. In conclusion, checking the preloading effects of transstimulation on the initial uptake of a ligand by the liver could be a useful criterion for carrier cycling and common use of the same carrier between two ligands. However, one cannot exclude those possibilities even if the preloading effects cannot be observed.

• Membrane and Water Treatment
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• v.7 no.2
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• pp.87-100
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• 2016

A numerical simulation of membrane evaporation process was carried out in this work. The aim of simulation is to describe transport of water through porous membranes applicable to the concentration of aqueous solutions. A three-dimensional mathematical model was developed which considers transport phenomena including mass, heat, and momentum transfer in membrane evaporation process. The equations of model were then solved numerically using finite element method. The results of simulation in terms of evaporation flux were compared with experimental data, and confirmed the accuracy of model. Moreover, profile of pressure, concentration, and heat flux were obtained and analyzed. The results revealed that developed 3D model is capable of predicting performance of membrane evaporators in concentration of aqueous solutions.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.35-38
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• 1998

The momentum, heat and mass transport in the melt of several sizes of crucibles are calculated using a three dimensional numerical simulation technique with and without the k-$\varepsilon$ turbulent model. When turbulent model is not used, non-axisymmetric profiles of velocity, temperature and oxygen concentration appear in the melt of all sizes of crucibles. Axisymmetric profiles are obtained when the k-$\varepsilon$ model is adopted.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.91-96
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• 2022

The photocatalytic degradation of salicylic acid takes place in several stages involving coupled phenomena, such as the transport of molecules and the chemical reaction. The systems of transport equations and the photocatalytic reaction are numerically solved using COMSOL Mutiphysics (CM) simulation software. CM will make it possible to couple the phenomena of flow, the transport of pollutants (salicylic acid) by convection and diffusion, and the chemical reaction to the catalytic area (bauxite or TiO2 doped by nanoparticles). The simulation of the conversion rate allows to correctly fit the experimental results. The temporal simulation shows that the reaction reaches equilibrium after a transitional stage lasting over one minute. The outcomes of the study highlight the importance of diffusion in the boundary layer and the usefulness of injecting micro-agitation into the microchannel flow. Under such conditions, salicylic acid degrades completely.

• Journal of Environmental Science International
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• v.3 no.1
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• pp.11-16
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• 1994

Generally, it is difficult to predict water quality in a tidal river, because tidal flows make the transport phenomena more complicated. The purpose of this study is to clarify long-term mass transport in a tidal river through suggestion of simulation model. A simulation model based on a Lagrangian coordinate system, which has the advantage reducing numerical dispersion, was used to calculate changes in concentration of chlorides. Several field surveys were conducted to verify calculated results. Concludingly, long-term behavior of mas transport in a tidal river can be represented using the model.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.73-86
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• 2011

Haze phenomena were analyzed to assess the impact of long range transport process on the air quality of Seoul and Busan. We statistically classified haze days observed in both Seoul and Busan into two types of haze cases: stagnant case and long-range transport case, and analyzed the air pollutant levels comparatively for each of the two cases for the period of 2000~2007. The results showed that the long-range transport haze case occurs less frequently with the occurrence frequency of 35.5% than stagnant case with the occurrence frequency of 64.5%. During the observed all haze days, all pollutants have high concentration in comparison with those under other meteorological conditions (Rain, Mist, Dust, Clear, Rain+Mist) except for only $PM_{10}$ of Dust case where its level shows highest among total 6 categorized conditions. The long range transport haze case shows similar levels of $PM_{10}$ and $NO_2$, but higher $SO_2$ and lower $O_3$ compared with stagnant haze cases, suggesting the importance of sulfur chemistry for long range transport haze case and local photochemistry for stagnant haze case. In addition, by employing the NOAA/HYSPLIT-4 backward trajectory model, we subdivided the long range transport haze cases into two different sources: urban anthropogenic high emission areas of central China, and natural emission sources over north China and/or Mongolia. The former long range transport haze case shows higher occurrence (with Seoul 70% and Busan 85%) than the latter haze case (with Seoul 30% and Busan <10%). This is also implying that the long haze phenomena occurred over Korea have been influenced by not only the anthropogenic emissions but also the natural dust emissions. These both emission sources can be good contributors in calculating the source-receptor relationship over Korean atmospheric environment.

• 한국전기화학회:학술대회논문집
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• 1998.10a
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• pp.45-45
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• 1998

• 한국전기화학회:학술대회논문집
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• 1998.10a
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• pp.44-44
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• 1998