Wicking법에 의한 분체 PMMA와 PVdF의 접촉각과 표면자유에너지 결정

임미애,노승백 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

The value of contact angle on powder polymethylmethacrylate(PMMA) and polyvinylidene fluoride(PVdF) has measured by wicking method on the base of Washburn equation for water, glycerol, formamide, diiodomethane, 1,1,2,2,-tetrabromoethane, 1-bromonaphthalene, and hexadecane. The measured values were comparable that of film type contact angle measurement. In wicking method, pore average radius has determined from measured values wetting height and mass of powder to liquid in packed column. From the measured contact angle values, surface free energy(γs) of powder PMMA and PVdF was determined by using geometric mean, van Oss approach method and equation of state of Neumann. It is shown that the results of γs depends on interaction with liquids. The solid-liquid interfacial free energy(γS L), interaction parameter(φ) and work of adhesion(WA)were also determined for powder PMMA and PVdF to water and organic liquids.

Preparation and Characterization of Ferrofluid by Chemical Precipitation Method

RHO,Seung Baik 계명대학교 산업기술연구소 1993 産業技術硏究所 論文報告集 Vol.16 No.1

The main purpose of this research work was the preparation of the magntic fluid (ferrofluid) which is a stable colloidal dispersion of subdomain magnetic particles in a carrier liquid, and the study of its applications. The magnetites of kerosene based ferrofluid (KBF) and water based ferrofluid (WBF) were prepared by chemical precipitation method. The optimum condition of magnetite (magnetic particle) formation and oleic acid adsorption was determined by examining various temperatures, precipitation times and pH conditions. The condition of magnetite formation is 60℃, for 10 minutes at pH 12.0, and the that of oleic acid adsorption is 80℃, for 30 minutes. The morphology and size of the magnetite of the ferrofluid is observed by the Transparency Electron Micrograph (TEM). In case of KBF, the adsorbed surfactant layer (oleic acid) is monolayer and in case of WBF the layer is double layer (oleic acid and Sodium Dodecyl Benzene Sulfonate). It was conformed that the size measured by the TEM and the size calculated from magnetization curve were corresponded each other. The magnetization and viscosity of ferrofluids is measured by the Vibrating Sample magnetometer(VSM) and the capillary type viscometer. The magnetization of the 0.6g/㎖ KBF is 22.3 emu/g and 0.45 g/㎖ WBF is 20.5 emu/g at 10,000 Gauss, respectively. The viscosity of the 0.6 g/㎖ KBF is 2.78 cP and 0.40 g/㎖ WBF is 7.18 cP at 29℃, respectively.

Development of a modified SRK EOS with composition dependent mixing rule to calculate the high pressure VLE for the binary and ternary Hydrocarbon-CO₂system

Rho, Seung Baik,Cho, Jung Ho 啓明大學校 産業技術硏究所 1997 産業技術硏究所 論文報告集 Vol.19 No.2

Phase behavior for nonpolar hydrocarbon mixtures can be described well by using any cubic equation of state with the conventional quadratic mixing rule. However, Vapor-liquid equilibria (VLE) for carbon dioxide rich hydrocarbon systems cannot be predicted with the conventional mixing rule because it is so difficult to predict to its phase behavior when the CO₂is added to hydrocarbon mixtures. VLE on binary and ternary of Hydrocarbon-CO₂mixtures are calculated using the modified Soave-Redlich -Kwong Equation of state(SRK- EOS) with various composition dependent mixing rules. The parameters of the alpha function are evaluated with the regression of pure component vapor pressure and the saturated liquid heat capacity departure at low temperature. The prediction of C₂H(6)-CO₂-N₂ternary VLE with only pure and binary experimental information is presenting better accuracy than the conventional mixing rule with parameters obtained from ternary experimental data. Without any empirically adjusted parameters, we could obtain comparably good VLE calculated results, as those from other existing EOS+GE models, from low to high pressures. With this advanced approach, the VLE on binary and ternary CO₂rich mixtures are predicted with significantly better results those from other approaches.

내화물 슬레이트용 고체윤활제의 연구

노승백(Rho, Seung-Baik),이학일(Lee, Haakil),손기훈(Son, Ki Hun) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.3

본 논문은 내화물 슬레이트용 고체윤활제를 제조하기 위하여 Starch 및 Graphite의 함량 변화를 통하여 점도, 마찰계 수 및 마모성능을 평가하여 Starch, Graphite와 water 간의 적절한 함량 조합을 찾고자 하였다. 먼저 starch 15 wt%일 때 점도는 graphite 함량에 따라 점도 상승이 커짐을 알 수 있었다. 또한 마찰계수 시험에서는 starch 15 wt%이고, graphite 30 wt%일 때 마찰계수가 가장 적었다. 이는 물의 함량이 줄어들고 고체의 비율이 높아짐에 따라 흡착력이 낮아져 표면에서 피막이 조금씩 탈락되며 마찰계수가 상승하는 것으로 판단된다. 마모 시험결과 starch 15 wt%이면서, graphite 25 wt% 혹은 30 wt%일 때 가장 양호한 결과를 얻었다. In order to produce an optimal performance solid lubricant used in the refractory slates, various compositions of starch, graphite and water were evaluated by testing their viscosity, coefficient of friction and wear performance. At 15% starch content, the degree of viscosity increment rose in proportional to graphite content and the lowest coefficient of friction was observed when the graphite content was at 30 wt%. Our results demonstrate that, as the water content decrease, the ratio of solid content increases, which compromises the surface coating resulting in increase of coefficient of friction. The best wear test result was obtained when the starch content was at 15 wt% with graphite content at either 25 wt% or 30 wt%.

오염된 지하수에서 휘발성 유기물질 제거를 위한 Air Stripping Tower의 설계 기술

노승백(Seung Baik Rho),김동진(Dong Jin Kim) 大韓環境工學會 1996 대한환경공학회지 Vol.18 No.4

와이퍼 블레이드 고무의 염소처리방법과 EPMA를 이용한 표면특성연구

노승백(Seung-Baik Rho) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-

자동차의 와이퍼 블레이드(Wiper Blade, W/B)의 마찰계수를 낮추기 위하여 고무 표면을 염소 처리 하였다. 염소처리방법으로는 물 20.0ℓ에 35.0% 염산(HCl)과 5.25% 차아염소산소다(NaOCl)를 각각 300㎖, 400㎖를 첨가한 염소처리용액을 만든 후, 2분에서 20분 동안 처리하였다. 처리 후의 표면 특성 은 IR스펙트럼, 마찰계수 측정기, EPMA를 이용하였다. IR스펙트럼으로 부터 W/B 고무 표면의 염소 화 정도를 확인하였다. 마찰계수는 염소처리에 의해 크게 감소하였다. 특히, 염소화 초기에 보다 민감 한 영향을 나타내었다. 고무표면 특성을 고무 파단면의 길이 방향에 대하여 EPMA 선분석한 결과를 얻었다. EPMA에 의한 염소침투깊이는 위의 염소농도에서, 염소처리를 5분 실시한 후에 1.2  임을 알 수 있었다.

용액의 농도변화에 따른 친수성 - 소수성 분체의 표면 특성 연구 - 계면활성제 SDS , CTABr 수용액에 대한 분체 PMMA , PVC , PVdF 와 Aluminum 의 접촉각 -

노승백(Seung Baik Rho),임미애(Mi Ae Lim) 한국고분자학회 1999 폴리머 Vol.23 No.5

Wicking법에 의한 분체 고분자의 접촉각과 표면자유에너지 결정

노승백 ( Seung Baik Rho ),임미애 ( Mi Ae Lim ) 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.2

EPMA를 이용한 염소 처리된 와이퍼 블레이드 고무의 표면 특성 연구

노승백(Rho, Seung-Baik) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.5

자동차의 와이퍼 블레이드(WiperBlade,W/B)의 마찰계수를 낮추기 위하여 고무 표면을 염소 처리하였다.염소처리 방법으로는 물 20.0ℓ에 35.0% 염산(HCl)과 5.25% 차아염소산소다(NaOCl)를 각각 300㎖,400㎖를 첨가한 염소처리용액을 만든 후,2분에서 20분 동안 처리하였다.처리 후의 표면 특성은 IR스펙트럼,마찰계수 측정기,EPMA를 이용하였다.IR스펙 트럼으로 부터 W/B고무 표면의 염소화 정도를 확인하였다.마찰계수는 염소처리에 의해 크게 감소하였다.특히,염소화 초기에 보다 민감한 영향을 나타내었다.고무표면 특성을 고무 파단면의 길이 방향에 대하여 EPMA선분석한 결과를 얻었다. EPMA에 의한 염소침투깊이는 위의 염소농도에서,염소처리를 5분 실시한 후에 1.2um 임을 알 수 있었다. The vehicle wiper blade(W/B) to lower the friction coefficient of the rubber surface after the surface treatment with chlorine were investigated. IR spectrum from W/B was used to determine the extent of chlorination of the rubber surface. Coefficient of friction is significantly reduced by the treatment with chlorine. In particular, the more sensitive influence on the initial chlorination. Rubber surface properties with respect to the longitudinal direction of the cutting plane were obtained by EPMA line analysis results. Penetration depth by EPMA chlorine concentration(20.0 ℓ of water for 35.0% hydrochloric acid(HCl) 300 ㎖ with 5.25% sodium hypochlorite(NaOCl) 400 ㎖), the chlorine treatment for 5 minutes was conducted to find that after 1.2um

열전달 모델을 이용한 폐수처리공정의 온도 예측

노승백(Rho, Seung-Baik) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.3

본 논문은 생물학적 활성오니 폐수처리공정의 열전달 모델식을 제시하여 공정의 온도를 예측하였다. 열전달 모 델은 폐수처리공정에 들어오고 나가는 모든 열을 고려하였다. 공정에 들어오는 열은 태양 복사열과 포기조 impeller의 기 계적 에너지의 변환열, 포기조 내의 생화학 반응열이다. 공정에서 나가는 열은 폐수 자체의 복사열, 포기작용에 의한 증 발열과 포기조 표면으로 나가는 전도열, 바람에 의한 대류열, 포기조와 지표면과의 전도열을 고려하였다. 들어오고 나가 는 모든 열은 기존의 열전달 경험식을 적용하였다. 적용된 경험식으로 폐수처리장 공정의 열전달 모델식을 제시하였다. 모델식으로 실제 폐수처리공정의 온도를 예측하였으며, 모델식 예측치와 실제값이 1.0℃ 이내로 일치하였다. The temperature change in the biologically activated sludge wastewater treatment process was predicted using the heat transfer model. All incoming and outgoing heats in wastewater treatment processes were considered. Incoming heats included the solar radiation heat, the heat from impeller mechanical energy, and the biochemical heat in the aeration process. Outgoing heats comprised the radiation heat from the waste itself, the heat of vaporization and surface aeration, the wind convection heat and the conduction heat between the surface and aerator. All heats were used as an input to the existing empirical heat transfer model. The heat transfer model of wastewater treatment processes is presented also. To test the validity of the heat transfer model, the operating conditions of the actual wastewater treatment plant were used. The temperatures were compared with the model temperatures. Model predictions were consistent within the 1.0℃.