• Title/Summary/Keyword: phase field model

Search Result 575, Processing Time 0.024 seconds

Concept Development of Resilience (회복력 (Resilience) 개념 개발)

  • 김혜성
    • Journal of Korean Academy of Nursing
    • /
    • v.28 no.2
    • /
    • pp.403-413
    • /
    • 1998
  • The Resilience is described as the personal capacity which brings psychosocial comeback. The role of nursing is to do its best to rehabilitate patients and to explore the individual in order to promote patients psychosocial change. However, as the current nursing is heavily physical nursing oriented, the identity of the nursing would be lost. Therefore this researcher reviewed if the concept of resilience can be applied to the nursing after examing the concept of resilience by Documents and Fieldwork. The methodology of this research is Hybrid Model developed by Schwartz-Barcott and Kim for the concept development and analysis. The process and procedure consist of The Theoretical Phase, The Fieldwork Phase and The Final Analytical Phase in accodance with the Hybrid Model. The followings the summary of the Research. 1. The Concept of Resilience Finally Analyzed by Documents and Fieldwork (1) The Redefinition of Resilience The resilience is the latent psychosocial capacity which minimize the negative emotion and promote the adaptation under adversity. Resilience appears as cognitive, emotional and behavioral response in the course of changing from negative response to positive response through the interaction of the individual and the enviroments in a given time. Resilience changes and decreases according to time and situation and it can be nurtured. Resilience is the higher concept including hardiness, sense of coherence and self-strength which maintain the health under stress. (2) The Attribute of Resilience The attribute of resilience was devided into psychological and social dimension. In psychological attributes, there are admittion of reality of situation, denial of negative emotion, desire to live, responsibility, confidence, courage, hope, pursuit of positive meaning, identification and pursuit of goal, self-esteem, reception, spontaneity, planning, positiveness, will power, flexibility and creativity. In social attributes, there are a sense of belonging, perception of social support and active social relations. (3) The Process of Resilience There are 4 resilience phases which were the process minimizing the possibility of the negative chain reactions under adversity, the process minimizing the negative emotion under adversity, the process gaining the desire to live and the process exposing the active social relations. 2. The Application Possibility of Resilience Concept to Nursing The resilience concept is the psychosocial capacity with which an individual manages adversity. As many nursing scientists have developed nursing theory based on this capacity and the identification of nursing has been established in this field, resilience is not the new conception in nursing. However, since resilience appears in the attributes related with the resilience process concretely, it would help a lot when nurses execute psychosocial nursing.

  • PDF

Conventional Fluid Dynamics and CFD Modeling for the Systematic Analysis of the Inside Flow of the Fischer-Tropsch Packed Bed Reactor (전통적인 유체역학 방법론과 CFD 결합을 통한 Fischer-Tropsch 고정층 반응기 내부 흐름의 체계적 모델링)

  • Kim, Hyunseung;Cho, Jaehoon;Hong, Gi Hoon;Moon, Dong Ju;Shin, Dongil
    • Journal of the Korean Institute of Gas
    • /
    • v.20 no.4
    • /
    • pp.65-77
    • /
    • 2016
  • Modeling for complex reacting flow in Fischer-Tropsch reactor is one of the challenges in the field of Computational Fluid Dynamics (CFD). It is hard to derive each and every reaction rate for all chemical species because Fisher-Tropsch reaction produces many kinds of hydrocarbons which include lots of isomers. To overcome this problem, after analyzing the existing methodologies for reaction rate modeling, non-Anderson-Schulz-Flory methodology is selected to model the detailed reaction rates. In addition, the inside flow has feature of multi-phase flow, and the methodologies for modeling multi-phase flow depend on the interference between the phases, distribution of the dispersed phase, flow pattern, etc. However, existing studies have used a variety of inside flow modeling methodologies with no basis or rationale for the feasibility. Modeling inside flow based on the experimental observation of the flow would be the best way, however, with limited resources we infer the probable regime of inside flow based on conventional fluid dynamics theory; select the appropriate methodology of Mixture model; and perform systematic CFD modeling. The model presented in this study is validated through comparisons between experimental data and simulation results for 10 experimental conditions.

The Kinetics of Anodic Dissolution and Repassivation on 316L Stainless Steel in Borate Buffer Solution Studied by Abrading Electrode Technique

  • Xu, H.S.;Sun, D.B.;Yu, H.Y.;Meng, H.M.
    • Corrosion Science and Technology
    • /
    • v.14 no.6
    • /
    • pp.261-266
    • /
    • 2015
  • The capacity of passive metal to repassivate after film damage determines the development of local corrosion and the resistance to corrosion failures. In this work, the repassivation kinetics of 316L stainless steel (316L SS) was investigated in borate buffer solution (pH 9.1) using a novel abrading electrode technique. The repassivation kinetics was analyzed in terms of the current density flowing from freshly bare 316L SS surface as measured by a potentiostatic method. During the early phase of decay (t < 2 s), according to the Avrami kinetics-based film growth model, the transient current was separated into anodic dissolution ($i_{diss}$) and film formation ($i_{film}$) components and analyzed individually. The film reformation rate and thickness were compared according to applied potential. Anodic dissolution initially dominated the repassivation for a short time, and the amount of dissolution increased with increasing applied potential in the passive region. Film growth at higher potentials occurred more rapidly compared to at lower potentials. Increasing the applied potential from 0 $V_{SCE}$ to 0.8 $V_{SCE}$ resulted in a thicker passive film (0.12 to 0.52 nm). If the oxide monolayer covered the entire bare surface (${\theta}=1$), the electric field strength through the thin passive film reached $1.6{\times}10^7V/cm$.

Numerical Calculation for Impedance of Horizontal Ground Electrode for Information and Communication Facilities with Considering Characteristics of Permittivity in Soil (토양의 유전율 특성을 고려한 정보통신설비용 수평접지전극의 임피던스 계산)

  • Ahn, Chang-Hwan
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.50 no.10
    • /
    • pp.245-251
    • /
    • 2013
  • An impedance of ground electrode for information and communication facilities has a significant relationship with the electrical characteristics of soil where the ground electrode is buried. Especially, the impedance of ground electrode is directly affected by the characteristics of permittivity and conductivity in soil as a function of a frequency of an applied electric field. The program based on the electromagnetic field model was developed in MATLAB. Because both permittivity and conductivity can not be modified in commercial programs. The permittivity of soil was applied with the Debye equation which is a model of dielectric relaxation. And the empirical equation of the conductivity in soil was quoted in other paper. In order to confirm the reliability of proposed program, the impedance measurement of ground electrode was carried out, which were compared with the results of simulation in commercial program. In result, it was confirmed that the impedance and phase different simulated by appling the characteristics of permittivity and conductivity in soil are in good agreement with the measured values than results of NEC.

Numerical Model Experiments on the Tidal Current Variations Due to the Bridge Piers Construction near the Straits of Narodo Islands (교각건설로 인한 나로도 협수로 부근해역에서의 조류변화 수치모형 실험)

  • LEE Moon-Ock
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.27 no.1
    • /
    • pp.47-58
    • /
    • 1994
  • Field observation and numerical experiments with a two-dimensional depth-integrated model were undertaken in order to investigate some of the effects on the flow structure resulting from the construction of a bridge connecting Kohung Peninsula and the Narodo Islands on the southern coast of Korea. Tidal currents passing through the straits between the Narodo Islands showed that, although the phase lagged one hour behind that passing through the strait between Kohung Peninsula and Naenarodo Island, it still kept strong flows of more than 80cm/sec near the bottom. The seawater temperature and salinity within the study area seemed to be higher southward but uniform vertically. The results of the drogue experiments in the straits between the Narodo Islands showed that the drogues moved northward of Sayangdo in the early part of the flood tide, but southward in the late part of the flood tide and finally stopped a mile from the east coast of Surakdo. On the other hand, the numerical computation showed that the flow structures after construction of the bridge piers were basically in line with those before construction of the bridge piers, except for the slight variations of velocities in the vicinity of the bridge piers. A large scale clockwise circulation has been confirmed in the south area of Namsungri of Kohung Peninsula from the computational results of tide-induced residual currents. Referring to these computational results, the impact category on the flow structures due to the bridge piers construction has been estimated to be within around 2km. The results were in good agreement with the field observations.

  • PDF

ANALYSES OF ANNULAR LINEAR INDUCTION PUMP CHARACTERISTICS USING A TIME-HARMONIC FINITE DIFFERENCE ANALYSIS

  • Seong, Seung-Hwan;Kim, Seong-O
    • Nuclear Engineering and Technology
    • /
    • v.40 no.3
    • /
    • pp.213-224
    • /
    • 2008
  • The pumping of coolant in a liquid metal fast reactor may be performed with an annular linear induction electro-magnetic (EM) pump. Linear induction pumps use a traveling magnetic field wave created by poly-phase currents, and the induced currents and their associated magnetic field generate a Lorentz force, whose effect can be the pumping of the liquid metal. The flow behaviors in the pump are very complex, including a time-varying Lorentz force and pressure pulsation, because an induction EM pump has time-varying magnetic fields and the induced convective currents that originate from the flow of the liquid metal. These phenomena lead to an instability problem in the pump arising from the changes of the generated Lorentz forces along the pump's geometry. Therefore, a magneto-hydro-dynamics (MHD) analysis is required for the design and operation of a linear induction EM pump. We have developed a time-harmonic 2-dimensional axisymmetry MHD analysis method based on the Maxwell equations. This paper describes the analysis and numerical method for obtaining solutions for some MHD parameters in an induction EM pump. Experimental test results obtained from an induction EM pump of CLIP-150 at the STC "Sintez," D.V. Efremov Institute of Electro-physical Apparatus in St. Petersburg were used to validate the method. In addition, we investigated some characteristics of a linear induction EM pump, such as the effect of the convective current and the double supply frequency (DSF) pressure pulsation. This simple model overestimated the convective eddy current generated from the sodium flow in the pump channel; however, it had a similar tendency for the measured data of the pump performance through a comparison with the experimental data. Considering its simplicity, it could be a base model for designing an EM pump and for evaluating the MHD flow in an EM pump.

Optimization of Nitrogen and Phosphorus Removal of Temporal and Spatial Isolation Process by Model Simulation System (시공간 동시분할 공정 시뮬레이션을 통한 질소 및 인 제거 최적화 방안)

  • Ryu, Dongjin;Chang, Duk;Shin, Hyungsoo;Park, Sangmin;Hong, Kiho;Kim, Sooyoung;Kim, Myoungjun
    • Journal of Korean Society on Water Environment
    • /
    • v.23 no.2
    • /
    • pp.206-215
    • /
    • 2007
  • The objective of this study was to establish the optimal system operating strategies for nitrogen and phosphorus removal through model simulation system built for advanced wastewater treatment targeting on simultaneous temporal/special phase isolation BNR process. The simulation system was built with unit process modules using object modules in GPS-X code. The system was well verified by field experiment data. Simulation study was carried out to investigate performance response to design and operation parameters, i.e. hydraulic retention time (HRT), solids retention time (SRT), and cycle time. The process operated at HRTs of 10~15 hours, longer SRTs, and cycle time of 2 hours showed optimal removal of nitrogen. The HRTs of 10~15 hours, SRTs of 20~25 days, and longer cycle time was optimal for phosphorus removal. Both simulation and field studies showed that optimal operating strategies satisfying both the best nitrogen and phosphorus removals include HRTs ranged 10~15 hours, SRTs ranged 20~25 days, and cycle times of 4~8 hours. The simulation system with modularization of generalized components in BNR processes was, therefore, believed to be a powerful tool for establishing optimal strategies of advanced wastewater treatment.

Current status and issues of motion drawing education for animation (애니메이션을 위한 모션드로잉 교육의 현황과 과제)

  • Lee, Jong Han;Park, Sung Won
    • Cartoon and Animation Studies
    • /
    • s.35
    • /
    • pp.129-153
    • /
    • 2014
  • This study is a process of studying an alternative educational model and a preceding analysis process of the study where a teaching method considering the expertise of animation is applied with a perspective of effectively increasing the animation drawing ability. The animation field which is the image contents is a visual art that delivers the story through the movement of the subject, and when looking only at the education related to the drawing, the items required for expertise should be clarified and the development of a systematic curriculum and teaching method is required. Therefore in this study, it aims to review the necessity of education model development by analyzing the educational contents and domestic and foreign curriculums that corresponds to the categorization of motion drawing considered with expertise of animation. As a result, it will be used as a basis for planning the educational model of a subject in the category of motion drawing. This process corresponds to the analysis phase of ADDIE educational model development and in the future, as an attempt for integrated studies, will lead to a study of developing and applying the educational model based on the functions of brain and creative mechanism.

Numerical simulation of gasification of coal-water slurry for production of synthesis gas in a two stage entrained gasifier (2단 분류층 가스화기에서 합성가스 생성을 위한 석탄 슬러리 가스화에 대한 수치 해석적 연구)

  • Seo, Dong-Kyun;Lee, Sun-Ki;Song, Soon-Ho;Hwang, Jung-Ho
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2007.11a
    • /
    • pp.417-423
    • /
    • 2007
  • Oxy-gasification or oxygen-blown gasification, enables a clean and efficient use of coal and opens a promising way to CO2 capture. The coal gasification process of a slurry feed type, entrained-flow coal gasifier was numerically predicted in this paper. The purposes of this study are to develop an evaluation technique for design and performance optimization of coal gasifiers using a numerical simulation technique, and to confirm the validity of the model. By dividing the complicated coal gasification process into several simplified stages such as slurry evaporation, coal devolatilization, mixture fraction model and two-phase reactions coupled with turbulent flow and two-phase heat transfer, a comprehensive numerical model was constructed to simulate the coal gasification process. The influence of turbulence on the gas properties was taken into account by the PDF (Probability Density Function) model. A numerical simulation with the coal gasification model is performed on the Conoco-Philips type gasifier for IGCC plant. Gas temperature distribution and product gas composition are also presented. Numerical computations were performed to assess the effect of variation in oxygen to coal ratio and steam to coal ratio on reactive flow field. The concentration of major products, CO and H2 were calculated with varying oxygen to coal ratio (0.2-1.5) and steam to coal ratio(0.3-0.7). To verify the validity of predictions, predicted values of CO and H2 concentrations at the exit of the gasifier were compared with previous work of the same geometry and operating points. Predictions showed that the CO and H2 concentration increased gradually to its maximum value with increasing oxygen-coal and hydrogen-coal ratio and decreased. When the oxygen-coal ratio was between 0.8 and 1.2, and the steam-coal ratio was between 0.4 and 0.5, high values of CO and H2 were obtained. This study also deals with the comparison of CFD (Computational Flow Dynamics) and STATNJAN results which consider the objective gasifier as chemical equilibrium to know the effect of flow on objective gasifier compared to equilibrium. This study makes objective gasifier divided into a few ranges to study the evolution of the gasification locally. By this method, we can find that there are characteristics in the each scope divided.

  • PDF

Analytical comparison of structural changes of plastic cell-based therapeutic drug storage containers when exposed to cryogenic environments (플라스틱 세포치료제 보관용기의 극저온 환경 노출 시 구조적 변화에 대한 해석적 비교)

  • Park, Jeong-Yeon;Lee, Dong-Mok;Lee, Jienny;Lee, Sun-ray;Yoon, Gil-Sang
    • Design & Manufacturing
    • /
    • v.14 no.2
    • /
    • pp.1-6
    • /
    • 2020
  • Recently, research and commercialization related to the field of cell-based therapeutic drug development has been actively conducted. In order to maintain cell viability and prevent contamination, refrigeration preservation devices, such as CRF (controlled rate freezer) or vapor type LN2 tanks have been developed. On the other hand, the storage container for liquid nitrogen tanks currently on sale minimizes the flow structure to prevent structural defects when stored in a liquid nitrogen tank having a high thermal conductivity than vapor nitrogen. If the cell-based treatment drug is stored in the gaseous LN2 tank as it is, the cell survival after thawing is greatly reduced. It was estimated that the existing storage container structure was a factor that prevented the rapid entry and circulation of gaseous nitrogen into the container. Therefore, this study intends to propose a new supercellular storage container model that can maintain the mechanical strength while maximizing the fluid flow structure. To this end, we estimated that the structural change of the storage container effects on the equivalent stress formed around the through-holes of them when exposed to a cryogenic environment using thermal-structural coupled field analysis. As a result of storage experiments in the gas phase tank of the cell-based therapeutic agent using the developed storage container, it was confirmed that the cell growth rate was improved from 66% to 77%, which satisfied the transportation standards of the FDA(Food and Drug Administration) cell-based therapeutic agent.