• KSBB Journal
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• 제27권3호
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• pp.145-150
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• 2012

This study was accomplished using packed bed column reactors that contain nonsurface-modified polypropylene media and surface-modified media from hydrophobic surface property into hydrophilic property by ion beam irradiation. The objectives of this research was investigated the characteristics of organic compounds removal and microbe attachment from sewage of school cafeteria in these reactors. In 736.8 mg/L of the average inflow $COD_{Cr}$ concentration the reactors with and without surface modification showed 81.8% and 70.3% of average $COD_{Cr}$ removal efficiencies, respectively, which proves the $COD_{Cr}$ removal efficiency of surface-modified media reactor is higher than that of nonsurface-modified media reactor. After 90 days, there were maximum differences between modified system and non-modified system. In that time the maximum removal efficiency of $COD_{Cr}$ was 96.5% in modified system and was 85.2% in non-modified system that showed removal efficiency of surface-modified media system is 11.3% higher than that of nonsurface-modified media system. The average removal efficiency of SS was 80.4% for the surface modified system and 61.6% for the non-modified system under same condition. Also, the reactor of surface-modified media has advantage on microbe attachment and biofilm formation.

• KSBB Journal
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• 제23권1호
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• pp.70-76
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• 2008

본 연구에서는 생물막법 중 고정 생물막을 이용한 무산소/호기 시스템으로 구성된 반응기에서 표면을 이온빔으로 조사하여 소수성인 표면 물성을 친수성으로 개질한 표면개질(surface-modified) 담체와 표면을 개질하지 않은 비개질 담체(non-modified)를 각각 이용하여 하수의 유기물, T-N 그리고 T-P의 제거 특성을 알아보았다. 여기에 사용된 담체는 폴리에틸렌 재질로서 원통형 플라스틱 담체이다. 수리학적 체류시간(HRT)에 따른 제거율의 차이를 알아본 결과, $COD_{cr}$의 경우 HRT를 16hr 이상 주었을 경우 개질 담체를 사용한 반응기 (개질 담체 반응기)와 비개질 담체를 사용한 반응기(비개질 담체 반응기) 모두 95% 이상의 제거율을 보인 반면에 12hr일 경우 개질 담체 반응기는 95%, 비개질 담체 반응기는 92%의 제거율을 보였다. 동일한 조건에서 T-N 제거율은 개질 담체 반응기는 HRT에 따라 최고 70.2%에서 최저 54.8%의 제거율을, 비개질 담체 반응기는 최고 76.5%에서 최저 57.5%의 제거율을 보였다. 마지막으로, T-P 제거율을 알아본 결과, 개질 담체 반응기는 최고 69.8%에서 최저 59.4%의 제거율을 보인 반면에 비개질 담체 반응기는 최고 63.4%에서 최저 51.3%의 제거율을 보였다. 본 연구결과로 볼 때 하수처리 적용시 $COD_{cr}$와 T-P의 제거인 경우에 표면개질 담체를, T-N의 경우 비개질 담체를 사용한 것이 제거효율에서 유리한 것으로 판단된다.

• 스마트미디어저널
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• 제4권2호
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• pp.9-16
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• 2015

Fluids appear in innumerable phenomena; therefore, it is interesting to reproduce those phenomena by computer graphics techniques. However, this process is not trivial. We work with a fluid simulation that uses Navier-Stokes equations to model the fluid, a semi-Lagrangian approach to solve it and the level set method to track the surface of the fluid. Modified versions of the Navier-Stokes equations for computer graphics allow us to create a wide diversity of effects. In this paper, we propose a technique that allows us to integrate a force inspired by surface tension into the model. We describe which information we need and how to modify the model with this new approach. We end up with a modified simulation that has additional effects that might be suitable for computer graphics purposes. The effects that we are able to recreate are small waves and droplet-like formations close to the surface of the fluid. This model preserves the overall behavior governed by the Navier-Stokes equations.

• Membrane and Water Treatment
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• 제11권3호
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• pp.231-235
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• 2020

Industrialization and modern developments have led to an influx of toxic heavy metals into the aquatic environment, and the accumulation of heavy metals has serious adverse effects on humans. Among the various heavy metal treatment methods, adsorption is very useful and frequently used. Plastic materials, such as polypropylene and polyethylene, have been widely used as filter media due to their mechanical and chemical stability. However, the surface of plastic material is inert and therefore the adsorption capability of heavy metals is very limited. In this study, granular media and fiber media composed of polypropylene and polyethylene are used, and the surface modification was conducted in order to increase adsorption capability toward heavy metals. Oxygen plasma generated hydroxyl groups on the surface of the media to activate the surface, and then acrylic acid was synthesized on the surface. The grafted carboxyl group was confirmed by FT-IR and SEM. Heavy metal adsorption capability of pristine and surface modified adsorbents was also evaluated. Overall, heavy metal adsorption capability was increased by surface modification due to electrostatic interaction between the carboxyl groups and heavy metal ions. Fibrous PP/PE showed lower improvement compared to granular PP media because pore blockage occurred by the surface modification step, thereby inhibiting mass transfer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권3호
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• pp.214-224
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• 2011

Objective: This study examined the potential of the in vitro osteogenesis of microtopographically modified surfaces, RBM (resorbable blasting media) surfaces, which generate hydroxyapatite grit-blasting. Methods: RBM surfaces were modified hydroxyapatite grit-blasting to produce microtopographically modified surfaces and the surface morphology, roughness or elements were examined. To investigate the potential of the in vitro osteogenesis, the osteoblastic cell adhesion, proliferation, and differentiation were examined using the human osteoblast-like cell line, MG-63 cells. Osteoblastic cell proliferation was examined as a function of time. In addition, osteoblastic cell differentiation was verified using four different methods of an ALP activity assay, a mineralization assay using alizarin red-s staining, and gene expression of osteoblastic differentiation marker using RT-PCR or ELISA. Results: Osteoblastic cell adhesion, proliferation and ALP activity was elevated on the RBM surfaces compared to the machined group. The cells exhibited a high level of gene expression of the osteoblastic differentiation makers (osteonectin, type I collagen, Runx-2, osterix). imilar data was represented in the ELISA produced similar results in that the RBM surface increased the level of osteocalcin, osteopontin, TGF-beta1 and PGE2 secretion, which was known to stimulate the osteogenesis. Moreover, alizarin red-s staining revealed significantly more mineralized nodules on the RBM surfaces than the machined discs. Conclusion: RBM surfaces modified with hydroxyapatite grit-blasting stimulate the in vitro osteogenesis of MG-63 cells and may accelerate bone formation and increase bone-implant contact.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.95-98
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• 2006

Filtration by fibrous filter is one of the Principle methods used for removing pollutant particles in the liquid. Because of the increasing need to protect both human health and valuable devices from exposure to fine particles, filtration has become more important. Filters have been developed with modified surface charge characteristics to capture and adsorb particles by electrokinetic interaction between the filter surface and particles contained in water. The main purposes of this study are to develop and evaluate the performance evaluation of the apparatus for making a positively charged porous filter media and to analyze the surface characteristics of the filter media for capturing negavitely charged contaminants mainly bacteria and virus from water. The experimental apparatus consists of a mixing tank, a vacuum pumping system, a injection nozzle, a roller press and a controller. The filter media is composed of glass fiber(50-750 nm), cellulose($10-20{\mu}m$) and colloidal charge modifier. The characteristics of filter media is analyzed by SEM(Scanning Electron Microscopy), AFM(Atomic Force Microscopy) and quantified by measuring the zeta potential values.

• KSBB Journal
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• 제17권3호
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• pp.235-240
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• 2002

친수성 표면을 만들기 위하여 산소분위기에서 1 keV의 에너지를 갖는 아르곤 이온빔을 폴리프로필렌 담체의 표면에 조사하였다. 삼차 증류수에 대한 접촉각은 개질 전의 $78^{\circ}$에서 최적의 조건에서 $22^{\circ}$까지 감소하였다. 이온 보조 반응 후의 친수성 증가는 ether, carbonyl, carboxyl 등의 새로 형성된 작용기에 의한 것이며 극성 용매에 대한 안정성이 우수하므로 활성화된 표면이 폐수 내에서도 안정하다. 활성화된 폴리프로필렌 담체를 합성폐수내의 유기물을 제거하기 위한 bio-film공정에 적용하였다. 이온 보조 반응법으로 친수성 표면으로 개질된 PP 담체는 극성 용매내에서 극성작용기가 유지되었으므로 안정된 표면 특성을 이용하여 박테리아 부착의 생물막 공정에 대한 연구를 수행하여 미생물의 부착은 표면의 염기성 극성작용기에 의하여 증진됨을 확인하였다. 합성폐수에 대한 처리 효율은 30%까지 증가 하였으며 장시간에 걸친 COD 농도 감소 효과를 나타내었으므로 이온 보조 반응법에 의하여 처리된 PP고분자를 수질 개선용의 담체로 사용하여 처리효율을 증가시킬 수 있음을 확인하였다.

• 전기전자학회논문지
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• 제17권2호
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• pp.151-158
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• 2013

There are several kind of surface deformation display methods using the fuzzy model. In this paper, we describe three fuzzy display methods for a surface deformation and perform a comparative analysis between the modified fuzzy display method and some conventional fuzzy display methods. In each method, the analysis will be performed through computer simulation in order to show the performance of each algorithm. The results show that the modified method have improved the realism and can be used better than the conventional methods in practical applications.

• Journal of Electrochemical Science and Technology
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• 제6권4호
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• pp.111-115
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• 2015

In this work electrochemical oxidation of Ascorbic acid (AA) on the surface of Cobalt nano particle modified carbon paste electrode (CoNPsMCPE) was studied in alkaline media. CoNPs were green synthesized using Piper longum and a mixture of 5% (w/w) of it were made with carbon paste. CoNPs showed good electrocatalytic activity in alkaline media. Cyclic voltammetry (CV) and chronoamperometry (CA) were used to study the electrochemical performance of CoNPsMCPE. The number of monolayers on the surface of electrode was calculated as 1.08×10⁹ mol cm⁻² that is equal to that of metal Cobalt electrode. Diffusion coefficient of AA was determined using CA analysis which was equal to 1.5×10⁻⁶cm² s⁻¹.

• Korea-Australia Rheology Journal
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• 제16권4호
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• pp.175-182
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• 2004

Colloidal coating solution was prepared to enhance the hydrophilic property of the film surface. Water and ethanol were used as the dispersion media and (glycidoxypropyl) trimethoxysilane (GPS) as a binder in the colloidal silica coatings. Ethylene diamine was added to the colloidal silica solution as the curing agent. The colloidal silica solution was regarded as a hard-sphere suspension model with low volume fraction of the silica particles. Rheological properties of the silica suspensions modified with GPS have been investigated as a function of pH and concentration. The acidic solution showed high viscosity change by fast hydrolysis reaction and adsorption of the organic binders on the surface of silica particles. However, the hydrolysis was slow at the basic condition and the binders combined with themselves by condensation. The viscosity change was smallest at pH 7. The viscosity increased with the curing time after adding ethylenediamine, and the increase of viscosity at low pH was higher than that at high pH. The hydrophilic properties of the coating film were investigated by the contact angle of water and film surface. The smallest contact angle was shown under the strong acidic condition of pH 2.