• 제목/요약/키워드: effective diffusion

검색결과 844건 처리시간 0.031초

Development and Verification of Make-up Base Containing Aloe

  • Min, Hyejo;Kim, MinJung;Kim, Jeonghee
    • 패션비즈니스
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    • 제19권3호
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    • pp.121-129
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    • 2015
  • Aloe is a popular and effective agent used to cosmetic ingredient. It could replace artificial pigment on make-up base product and it is highly probable that might be useful as ingredients of multi-functional color cosmetic. In this study, we made a makeup base containing aloe extract and tested the effectiveness, safety and stability. Contents of polyphenol and flavonoid from the aloe extract were measured. To determine the antimicrobial effect from the aloe we used the paper disc diffusion method. We assessed the safety of make-up base containing aloe to cultured macrophage RAW 264.7 cells by MTT assay. Polyphenol contents of aloe extract and flavonoid respectively were 48 mg/g and 10 mg/g, in the 10 % concentration aloe extract. In case of aloe make-up base, the clear zone against Stapylococcus epidermidis was 9~11 mm and Stapylococcus aureus was also 9~11 mm. Growth activity of macrophage RAW 264.7 cells was over 80% in all concentration of make-up base containing aloe and general make base product. In conclusion aloe extract may be able to substitute the synthetic pigments and considered to be uses for ingredients multi-functional color cosmetic's ingredient.

생강 페이스트의 저장 안정성 (Storage Stability of Ginger(Zingiber officinale Roscoe) Paste)

  • 조길석;장영상;신효선
    • 한국식품영양과학회지
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    • 제26권6호
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    • pp.1140-1146
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    • 1997
  • Storage stability of ginger paste product was investigated from the standpoint of the inhibition of nonenzymatic browning and loss of gingerol contents. For the experimentations, control, 0.04% of N-acetyl-L-cysteine in ginger paste(NAcCys), and combination treatment of NAcCys, 0.92 of water activity and 6.30 of pH in ginger paste (mixed treatment) were stored at 3$0^{\circ}C$ for 40 days and analyzed for browning and gingerol contents. In addition the changes in sugars, organic acids, ascorbic acids, amino acids, and sensory quality were determined. The results revealed that the mixed treatment agent was effective in preventing both nonenzymatic browning and loss of gingerol contents. The inhibition by combination treatment might be resulted from the control of radical formations by sulfhydryl groups of NAcCys and the increase of diffusion resistance in lower water activity. Browning development and total gingerol contents were found to be correlated to some physicochemical characteristics of ginger paste; that is, browning development to amino acid and color value in sensory evaluation, and total gingerol contents to flavor in sensory evaluation.

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입자법을 이용한 비선형성 자유표면 유동의 수치 시뮬레이션 (Numerical Simulation of Non-linear Free-surface Motions Using Moving Particle Semi-implicit(MPS) Method)

  • 이병혁;정성준;류민철;김용수;김영훈;박종천
    • 한국해양공학회지
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    • 제21권6호
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    • pp.53-58
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    • 2007
  • A particle method, recognized as one of gridless methods, has been developed to investigate non-linear free-surface motions interacting with structures. This method is more feasible and effective than conventional grid methods for solving flow fieldswith complicated boundary shapes. The method consists of particle interaction models representing pressure gradient, diffusion, incompressibility, and the free-surface boundary conditions without grids. In the present study, broken dam problems with various viscosity values are simulated to validate the developed method.

미생물 안전을 위한 병원건물의 환기설계에 따른 공기 감염균 확산에 관한 시뮬레이션 연구 (A Study on simulation analysis of the microbe transport of air-born virus in hospital for microbiological safety)

  • 최상곤
    • 대한안전경영과학회지
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    • 제19권4호
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    • pp.115-123
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    • 2017
  • Recently there is a growing interest in the airborne spread of virus. In particular, there is growing interest in secondary infection through the air in the hospital. The distribution of air-born virus depends on ventilation system installed in a hospital. In this study, simulations were carried out to predict the move of air-born virus by ventilation system at hospital. Simulation results showed that pressure distribution was -372.05Pa ~ -3.45 Pa at 1st floor incase of only used mechanical exhaust at bathroom, shower stall, storage, kitchen etc.. if ventilation switch from used mechanical exhaust to mechanical exhaust & mechanical supply. Simulation results showed that pressure distribution was -336.44Pa at stair hall < -0.2Pa at bathroom < mean 1.19Pa at other room. So simulation results showed that using all of the mechanical supply and mechanical exhaust was more effective then the mechanical exhaust for maintain the pressure distribution in hospital. It was also showed that when using the mechanical supply and mechanical exhaust more effectively prevention of air born virus diffusion.

Research on systematization and advancement of shipbuilding production management for flexible and agile response for high value offshore platform

  • Song, Young-Joo;Woo, Jong-Hun;Shin, Jong-Gye
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제3권3호
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    • pp.181-192
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    • 2011
  • Recently, the speed of change related with enterprise management is getting faster than ever owing to the competition among companies, technique diffusion, shortening of product lifecycle, excessive supply of market. For the example, the compliance condition (such as delivery date, product quality, etc.) from the ship owner is getting complicated and the needs for the new product such as FPSO, FSRU are coming to fore. This paradigm shift emphasize the rapid response rather than the competitive price, flexibility and agility rather than effective and optimal perspective for the domestic shipbuilding company. So, domestic shipbuilding companies have to secure agile and flexible ship production environment that could respond change of market and requirements of customers in order to continue a competitive edge in the world market. In this paper, I'm going to define a standard shipbuilding production management system by investigating the environment of domestic major shipbuilding companies. Also, I'm going to propose a unified ship production management and system for the operation of unified management through detail analysis of the activities and the data flow of ship production management. And, the system functions for the strategic approach of ship production management are investigated through the business administration tools such as performance pyramid, VDT and BSC. Lastly, the research of applying strategic KPI to the digital shipyard as virtual execution platform is conducted.

초등학생의 블랜디드 러닝 기반 구조중심협동학습을 적용한 안전교육 프로그램 개발 및 효과 (Effects of a Structure-centered Cooperative Learning Safety Education Program based on Blended Learning for Elementary School Students)

  • 성정혜
    • 지역사회간호학회지
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    • 제30권1호
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    • pp.57-68
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    • 2019
  • Purpose: This study was performed to determine effects of a structure-centered cooperative learning safety education program based on blended learning for elementary school students. Methods: The study is developed in nonequivalent control group non-synchronized design. The subjects included 24 sixth grade students in the experimental group and 23 sixth grade students in the control group, respectively. To prevent diffusion of the experiment, it was carried out from May 20th to June 24th in 2015 with the control group and the other from August 26th to September 30th in 2015 with the experimental group. It was performed on experimental group after the structure-centered cooperative learning safety education program based on blended learning once a week for 6weeks. Data were analyzed by using descriptive statistics, paired t-test and independent t-test. Results: After the intervention, the experimental group showed significant increases in the self-directed learning attitudes and safety behavior compared to the control group except for the academic self-efficacy. Conclusion: The results indicate that the structure-centered cooperative learning safety education program based on blended learning program is effective in safety education for 6th graders.

Development of an Mg-Based Alloy with a Hydrogen-Storage Capacity over 6 wt% by Adding Graphene

  • Choi, Eunho;Kwak, Young Jun;Song, Myoung Youp
    • Metals and materials international
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    • 제24권6호
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    • pp.1403-1411
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    • 2018
  • Graphene (multilayer graphene) was chosen as an additive to improve the hydrogen uptake and release properties of magnesium (Mg). Five weight percent of graphene was added to pre-milled Mg by milling in hydrogen (reaction-involving milling). The hydrogen uptake and release properties of the graphene-added Mg were investigated. The activation of Mg-5graphene, which was prepared by adding 5 wt% graphene to Mg pre-milled for 24 h, was completed after the second cycle (cycle number, CN=2). Mg-5graphene had a high effective hydrogen-storage capacity (the quantity of hydrogen absorbed for 60 min) of 6.21 wt% at CN=3 at 593 K in 12 bar $H_2$. At CN=1, Mg-5graphene released 0.46 wt% hydrogen for 10 min and 4.99 wt% hydrogen for 60 min. Milling in hydrogen is believed to create defects (leading to facilitation of nucleation), produce cracks and clean surfaces (leading to increase in reactivity), and decrease particle size (leading to diminution of diffusion distances or increasing the flux of diffusing hydrogen atoms). The added graphene is believed to have helped the sample have higher hydrogen uptake and release rates, weakly but partly, by dispersing heat rapidly.

인시투 가스 측정이 가능한 경제적 가스 챔버 구현 및 센서 전압에 따른 가스 응답 특성 분석 (Economical Gas Chamber for In-situ Gas Measurement and Analysis of Gas Response Characteristics according to Sensor Voltage)

  • 최연석;이인환
    • 한국기계가공학회지
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    • 제18권5호
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    • pp.1-8
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    • 2019
  • Breath analysis using a portable device is better than the classical breath analysis system in terms of installation and operation. There is an increasing need to develop cost-effective equipment for testing gas sensors from the viewpoint of functionalities that can be applied applicable to portable devices. In the present study, an economical gas chamber for in-situ gas measurement is implemented with a single gas chamber without using expensive gas storage and control equipment; the gas response characteristics are analyzed using the above-described chamber. The main features of the implemented gas chamber are simple injection procedure, improved gas diffusion, easy measurement and cleaning, support for low-power mode measurement function for portable devices, and open source platform. Moreover, an analysis of gas response characteristics based on changes in sensor voltage show that the sensitivity and 90% response time are affected by the sensor voltage. Furthermore, the sensitivity graph has an inflection point in a specific range. The gas sensor applied in this study showed fast response speed and high sensitivity for sensor voltages of 3.0-3.5 V, regardless of the concentration of acetone gas, the target gas used in this study.

인쇄업에서 배출되는 반응성 VOCs 종류와 흡착 제거 방법의 적용 (Volatile organic compounds emitted from printing processes and their removal by adsorption)

  • 안해영;이윤경;송지현
    • 실내환경 및 냄새 학회지
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    • 제17권4호
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    • pp.396-403
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    • 2018
  • In this study, volatile organic compounds (VOCs) emitted from printing industries were analyzed, and an inorganic adsorbent, ${\gamma}-alumina$, was selected for the effective control of the VOC emissions. Printing processes commonly require inks, thinners, and cleaners, and they were mixed organic solvents containing aromatic compounds, ketones, and alcohols. Therefore, toluene, methyl ethyl ketone (MEK), and isopropyl alcohol (IPA) were selected as model compounds for this study. The adsorptive properties using ${\gamma}-alumina$ were determined for the model compounds. Both batch isotherm and continuous flow column tests demonstrated that the adsorption capacity of MEK and IPA was 3~4 times higher than that of toluene. The column test performed at an inlet toluene concentration of 100 ppm showed that an 80% breakthrough for toluene was observed after 3 hours, but both MEK and IPA were continuously adsorbed during the same time period. A numerical model simulated that the ${\gamma}-alumina$ could remove toluene at a loading rate of 0.4 mg/min only for a 4-hour period, which might be too short of a duration for real applications. Consequently, lifetime enhancement for ${\gamma}-alumina$ must be implemented, and ozone oxidation and regeneration would be feasible options.

침입형 및 치환형 화합물을 함유한 Ti 정밀주조용 Al2O3 주형의 α-case 계면반응 거동 (α-case Interfacial Reaction Behavior of Al2O3 Mold Containing Interstitial and Substitutional Compounds for Titanium Investment Casting)

  • 최봉재;이슬;김영직
    • 대한금속재료학회지
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    • 제49권7호
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    • pp.577-582
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    • 2011
  • The newly developed ${\alpha}-case$ controlled mold material for Ti investment castings was suggested in this research. The $Al_2O_3$ mold containing interstitial $TiO_2$ and substitutional $Ti_3Al$ was manufactured by the reaction between $Al_2O_3$ and Ti. It is obvious that as the $TiO_2$ and $Ti_3Al$ content in the mold surface were increased, the depth of the interfacial reaction was significantly reduced. In addition, substitutional $Ti_5Si_3$ in the mold surface owing to the reaction between Ti and $SiO_2$ from the binder was effective for ${\alpha}-case$ reduction. Therefore, the ${\alpha}-case$ reduction was accomplished by the diffusion barrier effect of interstitial $TiO_2$, substitutional $Ti_3Al$ and $Ti_5Si_3$.