• Title/Summary/Keyword: 미세 유동

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Stability and Processing Characteristics of Microencapsulated Squid Liver Oil by Fluidized Bed Coating (오징어 간유 미세캡슐의 유동층 코팅에 따른 품질 특성)

  • Hwang, Sung-Hee;Youn, Kwang-Sup
    • Korean Journal of Food Science and Technology
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    • v.40 no.6
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    • pp.621-625
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    • 2008
  • Squid oil is an abundant source of polyunsaturated fatty acids. This is particularly true for eicosapentaenoic acid and docosahexaenoic acid. The principal objective of this study was to extend the stability and improve the process aptitude of squid liver oil. Fluidized bed coatings were employed for coating with microencapsulated oil. The efficiency of the fluidized bed coating of the microencapsulated powder was over 90%. The apparent density with zein-DP was 0.6 g/mL, thereby indicating that flow ability had been improved as the result of an increase in specific gravity. The solubility of artificial gastric and enteric fluids with HPMC-FCC was 59.9 and 0%, respectively, whereas with zein-DP solubility was 0 and 31.0%, respectively. Polyunsaturated fatty acid retention results demonstrated that zein-DP coating was higher than HPMC-FCC, followed by the microencapsulated squid liver oil method. These results demonstrated that the application of microencapsulation and fluidized bed micro-coating techniques improved the stability and processing compatibility of squid liver oil.

A Study on the Thermal Boundary Layer Flow of a Micropolar Fluid in the Vicinity of a Wedge (미세극성 유체 유동장에 놓여진 쐐기형 물체주위의 열경계층에 관한 연구)

  • 김윤제
    • The Korean Journal of Rheology
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    • v.11 no.2
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    • pp.122-127
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    • 1999
  • The characteristics of thermal boundary layer flow of a micropolar fluid in the vicinity of a wedge has been studied with constant surface temperature. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equations. Numerical solutions are presented for the heat transfer characteristics with Pr=1 using the fourth-order Runge-Kutta method and their dependence on the material parameters is discussed. The distributions of dimensionless temperature and Nusselt number across the boundary layer are compared with the corresponding flow problems for a Newtonian fluid over wedges. Numerical results show that for a constant wedge angle with a given Prandtl number, Pr=1, the effect of increasing values of K results in an increasing thermal boundary thickness for a micropolar fluid, as compared with a Newtonian fluid. For the case of the constant material parameter K, however, the heat transfer rate for a micropolar fluid is lower than that of a Newtonian fluid.

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Investigation on the Size Effects of Polycrystalline Metallic Materials in Microscale Deformation Processes (미세성형 공정에서 다결정 금속재료의 크기효과에 관한 연구)

  • Kim, Hong-Seok;Lee, Yong-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.10
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    • pp.1463-1470
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    • 2010
  • Microforming, which exploits the advantages of metal forming technology, appears very promising in manufacturing microparts since it enables the production of parts using various materials at a high production rate, it has high material utilization efficiency, and it facilitates the production of parts with excellent mechanical properties. However, the conventional macroscale forming process cannot be simply scaled down to the micro-scale process on the basis of the extensive results and know-how on the macroscale process. This is because a so-called "size effect" occurs as the part size decreases to the microscale. In this paper, we attempt to develop an effective analytical and experimental modeling technique for explaining the effects of the grain size and the specimen size on the behavior of metals in microscale deformation processes. Copper sheet specimens of different thicknesses were prepared and heat-treated to obtain various grain sizes for the experiments. Tensile tests were conducted to investigate the influence of specimen thickness and grain size on the flow stress of the material. In addition, an analytical model was developed on the basis of phenomenological experimental findings to quantify the effects of the grain size and the specimen size on the flow stress of the material in microscale and macroscale forming.

간의 지방섭취세포의 구조와 기능

  • 원봉래
    • Journal of the korean veterinary medical association
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    • v.17 no.4
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    • pp.34-37
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    • 1981
  • FSC는 상시지방적을 보유하는 특성을 가지고 있으므로 지방섭취세포(fat-storing cell, FSC)라고 명명되어으며 유동에 노출하는 성세포, 내피세포와 달리 이 세포의 유동면은 교원직유와 내피세포에서 유래하는 윤랑선에 의하여 피복된다. 더욱이 이 세포는 각종 척추동물에 존재한다는 사실이 확인 되었으며 그 지방적은 동물의 종류에 따라 특유한 형을 구비하는 동시에 개체차가 없다. FSC는 이물탐식성이 없으며 지방적을 함유한 성세포와는 위치적, 기능적으로 다르다는 것이 증명되었다. 발생학적으로는 간엽세포에 속하며 유사분제에 의하여 증식능력을 가지고 있다. 이 세포에는 glycogen이 증명되며 모든 지방세포의 실험이 나타나는 성적에서와 유사하게 항시 지방을 합성하여 종의 특유한 형을 가진 지방적으로서 저장됨을 시사하였다. 전현적관륜에 의하여 FSC가 유동주위강(disse腔) 속에 있어 성세포, 내피세포와는 달리 유동에 노출하지 않고 항상 내피세포층과 교원직유에 의하여 유동에서 격리됨을 추정하였다. 이로 인하여 많은 학자들에 의하여 FSC가 승인을 받았다. 오늘날에는 유동을 둘러싸고 있는 상재세포가 내피세포, 성세포 및 FSC의 3종임이 인증이 되었다. 이 세포의 미세구조상의 특징은 기저막이 없는 공허한 세포로 보이나 항상지방적(空胞)을 보유하고 잘 발달한 조면소포체를 가지며 유동내피면에 따라 분기확산하는 돌기를 가지고 있다. 그리고 세포체는 유동주위강을 달리는 무수신경직유의 varicosity (사립체 및 신경결합소포를 함유한 신경종말)와의 사이에 adrenalin 작동성 synaps를 형성한다. FSC의 기능적 의의는 ㄱ, 간소엽내 교원직유형성에 참여 ㄴ. 유동내피하 돌기는 내피를 외측에서 지지하고 보강하며 또한 유동을 둘러싸고 연장하는 돌기는 수축하여 유동강을 축소한다. ㄷ. 지방을 저장하여 간세포의 energe원을 공급하며 VitaminA를 그 속에 저장한다. ㄹ. 간의 해독작용에 관여한다.

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Research on ANN based on Simulated Annealing in Parameter Optimization of Micro-scaled Flow Channels Electrochemical Machining (미세 유동채널의 전기화학적 가공 파라미터 최적화를 위한 어닐링 시뮬레이션에 근거한 인공 뉴럴 네트워크에 관한 연구)

  • Byung-Won Min
    • Journal of Internet of Things and Convergence
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    • v.9 no.3
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    • pp.93-98
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    • 2023
  • In this paper, an artificial neural network based on simulated annealing was constructed. The mapping relationship between the parameters of micro-scaled flow channels electrochemical machining and the channel shape was established by training the samples. The depth and width of micro-scaled flow channels electrochemical machining on stainless steel surface were predicted, and the flow channels experiment was carried out with pulse power supply in NaNO3 solution to verify the established network model. The results show that the depth and width of the channel predicted by the simulated annealing artificial neural network with "4-7-2" structure are very close to the experimental values, and the error is less than 5.3%. The predicted and experimental data show that the etching degree in the process of channels electrochemical machining is closely related to voltage and current density. When the voltage is less than 5V, a "small island" is formed in the channel; When the voltage is greater than 40V, the lateral etching of the channel is relatively large, and the "dam" between the channels disappears. When the voltage is 25V, the machining morphology of the channel is the best.

Technical Consideration for Production Data Analysis with Transient Flow Data on Shale Gas Well (셰일가스정 천이유동 생산자료분석의 기술적 고려사항)

  • Han, Dong-kwon;Kwon, Sun-il
    • Journal of the Korean Institute of Gas
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    • v.20 no.1
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    • pp.13-22
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    • 2016
  • This paper presents development of an appropriate procedure and flow chart to analyze shale gas production data obtained from a multi-fractured horizontal well according to flow characteristics in order to calculate an estimated ultimate recovery. Also, the technical considerations were proposed when a rate transient analysis was performed with field production data occurred to only $1^{st}$ transient flow. If production data show the $1^{st}$ transient flow from log-log and square root time plot analysis, production forecasting must be performed by applying different method as before and after of the end of $1^{st}$ linear flow. It is estimated by an area of stimulated reservoir volume which can be calculated from analysis results of micro-seismic data. If there are no bottomhole pressure data or micro-seismic data, an empirical decline curve method can be used to forecast production performance. If production period is relatively short, an accuracy of production data analysis could be improved by analyzing except the early production data, if it is necessary, after evaluating appropriation with near well data. Also, because over- or under-estimation for stimulated reservoir volume could take place according to analysis method or analyzer's own mind, it is necessary to recalculate it with fracture modeling, reservoir simulation and rate transient analysis, if it is necessary, after adequacy evaluation for fracture stage, injection volume of fracture fluid and productivity of producers.