• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.489-496
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• 2021

The performandce of polymer electrolyte membrane fuel cell depends on the effective management of heat and product water by the electrochemical reaction. This study is designed to investigate the parametric change of heat management along the channel of polymer electrolyte membrane. The model was developed by an aspen custom modeler that it can solve differential equation with distretization model. The model can simulate water transport through the membrane electrolyte that is coupled with heat generation. In order to verify the model, it is compared with the experimental data. The water transport behavior is then evaluated with the simulation model.

• Membrane and Water Treatment
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• 제6권5호
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• pp.411-422
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• 2015

Membrane modification by different concentrations of acrylic acid has been described. Grafting of acrylic acid to the surface of a polypropylene membrane was obtained by a Fenton-type reaction. Membrane permeability seemed to have been dependent on the value of pH in the solution. To explain tendency, a simple theoretical model was developed. The model incorporates explicitly statistical conformations of a polyacid chain grafted onto the pore surface. The charged capillary model with a varying diameter for porous membranes was then used to evaluate the permeability of the membrane. It has been shown both theoretically and experimentally that the permeability of a grafted membrane depends on the pH of the solution.

• 멤브레인
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• 제12권4호
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• pp.226-239
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• 2002

유기용매의 탈수화 공정의 거동을 예측할 수 있는 투과증발 판틀형 모듈에 대한 전산모사 모델을 확립하였는데 이는 공정의 분석 및 최적화의 도구로 사용할 수 있다. 확립한 모델은 물질, 열 및 농도 수지식으로 이루어졌으며 유한요소법의 수치해석을 사용하여 각 투과 특성들은 계산하였다. 본 전산모사에서는 모듈내 각 두개의 막 사이에 있는 단일 공급유로를 기본 미분단위부피로 사용함으로써 계산과정을 단순화하초 계산시간을 단축할 수가 있었다. 또한 모델식에 각 파라메타들을 실제 공정에서 직접 구하여 사용함으로써 공정모사의 정확성을 얻을 수가 있었다. 모사모델의 타당성을 화인하기 위해서 에탄올/물 혼합물을 모델 혼합물로 선정하여 상업 투과막인 $AzeoSep^{TM}$-2002를 통한 투과실험을 행하여 각 투과 특성들을 얻었으며 얻은 이들 값들과 모사 모델식으로부터 계산된 값들과 비교한 결과 서로 잘 일치함을 보여 본 모사모델의 타당성을 입증하였다. 또한 모사모델을 사용하여 연속식 및 회분식 투과공정에서의 에탄을 탈수 공정을 모사하였는데 모사 결과들은 공정 분석 및 최적화를 위한 기본자료로 활용할 수 있다. 본 연구에서는 모사결과를 토대로 회분식 공정과 연속식 공정을 비교 분석하였다.

• Membrane and Water Treatment
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• 제12권2호
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• pp.59-64
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• 2021

The rejection of sodium chloride (NaCl) and calcium chloride (CaCl2) single salt solutions were carried out for commercial nanofiltration NFDK membrane. Results showed that the NFDK membrane had a negative surface charge and had a higher observed rejection of 93.65% for calcium (Ca2+) ion and 78.27% for sodium (Na+) ions. Prediction of rejection for aqueous solutions of both salts was made using Donnan Steric Pore Model based on Extended Nernst-Planck Equation in addition to concentration polarization film theory. A MATLAB program was developed to execute the model calculations. Absolute Average Relative Error (% AARE) was found below 5% for real rejection of the NFDK membrane. This research could be used successfully to assess the membrane characterization parameter using a proposed procedure which can reduce the number of experiments.

• Journal of Korean Neurosurgical Society
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• 제49권6호
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• pp.323-328
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• 2011

Objective : Epidural fibrosis and adhesion are the main reasons for post-laminectomy sustained pain and functional disability. In this study, the authors investigate the effect of irradiated freeze-dried human amniotic membrane on reducing epidural adhesion after laminectomy on a rat model. Methods : A total of 20 rats were divided into two groups. The group A did not receive human amniotic membrane implantation after laminectomy and group B underwent human amniotic membrane implantation after laminectomy. Gross and microscopic findings were evaluated and compared at postoperative 1, 3 and 8 weeks. Results : The amount of scar tissue and tenacity were reduced grossly in group of rats with human amniotic membrane implantation (group B). On a microscopic evaluation, there were less inflammatory cell infiltration and fibroblast proliferation in group B. Conclusion : This experimental study shows that implantation of irradiated freeze-dried human amniotic membrane reduce epidural fibrosis and adhesion after spinal laminectomy in a rat model.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 춘계 총회 및 학술발표회
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• pp.52-53
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• 1993

The pervaporation behavior of EtOH/Water mixture through IPN membranes was predicted in this study. The pervaporation characteristics of single polymer membrane were modeled according to the "six-coefficients model" proposed by Brun. In the case of the IPN membrane, two models were proposed according to the phase structure of the IPN. For a uniphase membrane with no phase separation, the compositional average of the single polymer membrane was used. in the case of the phase separated IPN's two cases existed. The first was the island and sea model: in which one phase was continuous and the other was dispersed. The second was the co-continuous model where two continuous phases existed. For these cases, the permeation rate and the separation factor of the IPN membrane were calculated using the experimental sorption data and the cornponent polymer properties. Comparison with the experimental data indicated that these models could be used to predict the performances of IPN membranes depending on the morphology of the IPN.

• Computers and Concrete
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• 제1권3호
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• pp.325-354
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• 2004

Slabs in buildings and bridge decks, which are restrained against lateral displacements at the edges, have ultimate strengths far in excess of those predicted by analytical methods based on yield line theory. The increase in strength has been attributed to membrane action, which is due to the in-plane forces developed at the supports. The benefits of compressive membrane action are usually not taken into account in currently available design methods developed based on plastic flow theories assuming concrete to be a rigid-plastic material. By extending the existing knowledge of compressive membrane action, it is possible to design slabs in building and bridge structures economically with less than normal reinforcement. Recent research on building and bridge structures reflects the importance of membrane action in design. This paper describes the finite element modelling of membrane action in reinforced concrete slabs through optimisation of a simple concrete model. Through a series of parametric studies using the simple concrete model in the finite element simulation of eight fully clamped concrete slabs with significant membrane action, a set of fixed numerical model parameter values is identified and computational conditions established, which would guarantee reliable strength prediction of arbitrary slabs. The reliability of the identified values to simulate membrane action (for prediction purposes) is further verified by the direct simulation of 42 other slabs, which gave an average value of 0.9698 for the ratio of experimental to predicted strengths and a standard deviation of 0.117. A 'deflection factor' is also established for the slabs, relating the predicted peak deflection to experimental values, which, (for the same level of fixity at the supports), can be used for accurate displacement determination. The proposed optimised concrete model and finite element procedure can be used as a tool to simulate membrane action in slabs in building and bridge structures having variable support and loading conditions including fire. Other practical applications of the developed finite element procedure and design process are also discussed.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.152-154
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• 2004

A new model of selectively preferential sorption-facilitated transport with fixed site carriers was advanced in this paper. A number of experiments were arranged to demonstrate the ideal above. Preliminary results were obtained from the experiments, and shown the model was applicable for many membrane processes, such as RO, ED, gas separation and liquid membranes etc.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.59-62
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• 1998

1. 서론 : 막내부에서 물질전달을 설명하는 이론으로 현재 solution-diffusion model과 pore-flow model 두 가지가 있다. 이 중에서 흡착, 확산, 탈착의 3과정을 거치는 solution-diffusion model이 주로 사용되고 있다. 본 연구에서는 solution-diffusion model 에서 상호확산계수를 구하기 위해서 Vrentas-Duda식을 이용하여 자기확산계수를 구하고 Bearman식으로부터 상호확산계수를 구하는 과정을 UNIFAC-FV와 modified UNIFAC-FV을 이용하여 계산하였으며 Flory-Huggins식을 이용한 기존방법과 비교하였다.(생략)

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 심포지움시리즈 Jan-98 역삼투용 분리막 기술 및 응용
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• pp.1-30
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• 1998

1. RO History 2. Asymmetric Membranes by Phase Inversion 3. Thin Film Composite (TFC) Membrane 4. Structure and Property Relationship of TFC Membrane 5. Membrane Materials 6. Tranport Mechanism(Model) 7. Membrane Characters in Separation Process 8. Concentration Polarization and Fouling Phenomenon 9. RO Membrane Module Configuration and System Design 10. Futrue Trend in RO Industry