• Title/Summary/Keyword: Fluid Mixing Analysis

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Content and Educational Needs for Fundamental Nursing Practice (기본간호실습 교육 현황 및 실습교육 필요도)

  • Kim, Kyung-Hee;Chang, Sung-Ok;Kang, Hyun-Sook;Kim, Keum-Soon;Kim, Jong-Im;Kim, Hwa-Soon;Park, Jin-Hee;Eom, Mi-Ran;Youn, Mi-Sun;Lee, Og-Cheol;Won, Jong-Soon
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.18 no.4
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    • pp.506-519
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    • 2011
  • Purpose: The purpose of this study was to identify content of Fundamental Nursing Practice (FNP) and the educational needs for nursing practice items in schools of nursing. Methods: Participants were 81 professors who were teaching FNP and 166 clinical nurses. The research questionnaire included 148 practice items, which were selected by content analysis of 7 FNP textbooks. Data were collected from May 20 to July 27, 2011 and analyzed using descriptive statistics and t-test with SPSS 17.0. Results: The research findings showed that : 1) the seven items included in the education content of all schools of nursing were putting on sterile gloves, checking radial pulse, checking blood pressure in the arm, Foley catheterization, injection preparation with ampule, intramuscular injection in the buttocks, and mixing intravenous fluid. Fifty items were included in the content in more than 80% of the schools. 2) Educational domains needing emphasis were medication, infection control, health assessment, oxygenation, urinary elimination, activity/positioning, and nutrition. There were significant differences in reported educational needs between professors and clinical nurses for 62.8% of practice items. Conclusions: Results indicated that standardization of FNP education contents using the findings of this study should lead to improvement in quality of FNP education.

Heat Exchanger Design Analysis for Propellant Pressurizing System of Satellite Launch Vehicles (소형위성 발사체용 추진제 가압 열교환기 설계 해석)

  • Lee H. J.;Han S. Y.;Chung Y. G.;Cho N. K.;Kil G. S.;Kim Y. K.
    • Journal of computational fluids engineering
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    • v.9 no.3
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    • pp.49-56
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    • 2004
  • A heated and expanded helium is used to pressurize liquid propellants in propellant tanks of propulsion system of liquid propellant launch vehicles. To produce a heated and expanded helium, an hot-gas heat exchanger is used by utilizing heat source from an exhausted gas, which was generated in a gas generator to operate turbine of turbo-pump and dumped out through an exhaust duct of engine. Both experimental and numerical approaches of hot-gas heat exchanger design were conducted in the present study. Experimentally, siliconites - electrical resistance types - were used to simulate the full heat condition instead of an exhausted gas. Cryogenic heat exchangers, which were immersed in a liquid nitrogen pool, were used to feed cryogenic gaseous helium in a hot-gas heat exchanger. Numerical simulation was made using commercially utilized solver - Fluent V.6.0 - to validate experimental results. Helically coiled stainless steel pipe and stainless steel exhausted duct were consisted of tetrahedron unstructured mesh. Helium was a working fluid Inside helical heat coil and regarded as an ideal gas. Realizable k-』 turbulent modeling was adopted to take turbulent mixing effects in consideration. Comparisons between experimental results and numerical solutions are Presented. It is observed that a resulted hot-gas heat exchanger design is reliable based on the comparison of both results.

Effect of Geometric and Dynamic Parameters on Mixing Characteristic in an Internal-Loop Apparatus (내부 순환 장치의 크기 및 유속 변화에 따른 혼합특성)

  • 최윤찬;김동석
    • KSBB Journal
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    • v.11 no.4
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    • pp.405-410
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    • 1996
  • This paper discussed the dispersion effect according to the geometrical variation of an internal-loop spparatus by the method of pulse injection of a tracer. The Bodenstein number, which is the dimensionless group characterizing the effect of dispersion, was decreased with increasing the superficial gas velocity in the 50L and the 500L apparatus. But, in the 5L apparatus, the Bodenstein number was increased with increasing the superficial gas velocity in the range of 0 to 2cm/sec but above that range the rate of increase was dropped down to give a constant value because of the phenomenon of gas disengagement. The principle of similarity based on dimensional analysis was applied to design a pilot scale internal-loop apparatus. The effect of dispersion was examined in three different internal-loop apparatus to give the following correlation with major geometric and fluid dynamic properties as variables. B0=4.4014ReG0.117 ReL-0.0065(Hr/Dr)0.76(Dd/Dr)-0.76

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Analysis of the Hydraulic Behaviour in the Nearshore Zone by a Numerical Model (수치모형에 의한 연안해역 해수운동의 분석)

  • Lee, Hee-Young;Jeoung, Sun-Kil
    • Water for future
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    • v.27 no.2
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    • pp.73-83
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    • 1994
  • The unproper development of the nearshore zone can enhance the diffusion of pollutant in the nearshore zone resulting in unbalanced sediment budget of beach which causes alteration of beach topography. Therefore, it is required to predict the effects of the envirnmental change quantitatively. In this paper, the depth-averaged and time-averaged energy balance equation is selected to acount for the wave transformation such as refraction, shoaling effect, the surf zone energy disipation, wave breaking index and bore, due to wave breaking in the shore region.(Numerical solutions are obtained by a finite difference method, ADI and Upwind. For the calculation of the wave-induced current, the unsteady nonlinear depth-averaged and time-averaged governing equation is derived based on the continuity and momentum equation for imcompressible fluid.) Numerical solutions are obtained by finite difference method considering influences of factors such as lateral mixing coefficient, bed shear stress, wave direction angle, wave steepness, wave period and bottom slope. The model is applied to the computation of wave transformation, wave-induced current and variation of mean water leel on a uniformly sloping beach.

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Study on optimum structure of air-lift bio-reactor using numerical analysis of two-phase flow (이상 유동 수치해석을 이용한 기포 구동 생물 반응기 내부 최적 구조에 관한 연구)

  • Kim, San;Chung, Ji Hong;Lee, Jae Won;Sohn, Dong Kee;Ko, Han Seo
    • Journal of the Korean Society of Visualization
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    • v.17 no.3
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    • pp.24-31
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    • 2019
  • Recently, an air-lift bio-reactor operated by micro bubbles has been utilized to product hydrogen fuel. To enhance the performance, characteristics of hydrodynamics inside the bio-reactor were analyzed using a numerical simulation for two-phase flow. An Eulerian model was employed for both of liquid and gas phases. The standard k-ε model was used for turbulence induced by micro bubbles. A Population Balance Model was employed to consider size distribution of bubbles. A hollow cylinder was introduced at the center of the reactor to reduce a dead area which disturbs circulation of CO bubbles. An appropriate diameter of the draft tube and hollow cylinder were optimized for better performance of the bio-reactor. The optimum model could be obtained when the cross-sectional area ratio of the hollow cylinder to the reactor, and the width ratio of the riser to the downcomer approached 0.4 and 3.5, respectively. Consequently, it is expected that the optimum model could enhance the performance of the bio-reactor with the homogeneous distribution and higher density of CO, and more effective mixing.

Chemical Characterization of Oscillatory Zoned Tourmaline from Diaspore Nodule, an Aluminum-rich Clay Deposit, Milyang, South Korea (밀양 고알루미나 점토광상 다이아스포아 단괴내의 진동누대 전기석의 화학적 특징)

  • Choo, Chang-Oh;Kim, Yeong-Kyoo
    • Journal of the Mineralogical Society of Korea
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    • v.18 no.3 s.45
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    • pp.227-236
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    • 2005
  • Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.

Numerical Analysis of Single Phase Thermal Stratification in both Cold Legs and Downcomer by Emergency Core Cooling System Injection : A Study on the Necessity to Consider Buoyancy Force Term (비상노심냉각계통 주입에 따른 저온관 및 강수관에서 단상 열성층 수치해석 : 부력항 고려 필요성에 관한 연구)

  • Lee, Gong Hee;Cheong, Ae Ju
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.12
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    • pp.654-662
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    • 2017
  • When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

On Numerical Modeling of Kerosene/Liquid Oxygen Coaxial Swirl Injectors (케로신/액체산소 동축 와류형 분사기에 대한 수치해석 모델 고찰)

  • Kim, Seong-Ku;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.729-732
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    • 2010
  • The present study has been motivated by the development of a reliable numerical methodology for simulation of kerosene/LOx coaxial swirl injectors. To deal with thermodynamic non-ideality and anomalies of transport properties pronounced at supercritical pressures, a set of subroutine libraries has been constructed based on the cubic equations of state, and applied to an existing flamelet analysis code. For computational efficiency, two-dimensional axisymmetric RANS formulation with swirl was adopted and validated successfully against an isothermal coaxial swirling jet. For the actual problem with high pressure combustion, however, numerical results show that the RANS models yield excessive production of turbulence probably due to high density gradient magnitude in the vicinity of mixing layer of swirling film flow, and imply strongly further improvement of the turbulence models.

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A Basic Study on the Marine Anti-Fouling Coating Using Cellulose Nanofiber (셀룰로오스 나노섬유를 활용한 해양 방오 코팅제에 관한 기초 연구)

  • Jang, Nag-Seop;Kim, Tae-Kyun;Oh, Hong-Seob
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.4
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    • pp.469-477
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    • 2021
  • In this study, the mechanical property of anti-fouling coating using CNF was evaluated to prevent the durability and stability of structure exposed the marine environment. Anti-fouling coating using CNF was prepared by CNF, AKD and waste glass powder, and contact angle test, drying time, viscosity analysis and microstructure were performed. When coating on one number of times, It was showed to relatively high hydrophobic performance in steel. And It was confirmed that the contact angle increased as the content of AKD increased in cement mortar. When coating on three number of times, the surface was confirmed super-hydrophobic at maximum of 151.6°. When mixing waste glass powder, the surface was showed to relatively high hydrophobic. It is pseudo plastic fluid when CNF and distilled water were prepared in a ratio of 1:1, And Anti fouling coating is judged to be suitable for use as coating on marine structure.

An Image Evaluation According to the Constituent Elements of Skirt Designs in Modern Men's Fashion - Focusing on Gwangju City's Generation Z Male and Female College Students - (현대 남성패션에 나타난 스커트 디자인의 구성적 요소에 따른 이미지 평가 - 광주광역시 Z세대 남녀 대학생을 중심으로 -)

  • Yang, Hyo-Jung
    • Fashion & Textile Research Journal
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    • v.23 no.2
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    • pp.159-173
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    • 2021
  • This study attempted to investigate the perspective of the skirts of male and female students by analyzing the differences in image evaluation according to the constituent elements (type, length, and wearing method) of men's skirt designs in modern fashion. The study included 109 male and female college students from Generation Z residing or whose life center was in Gwangju Metropolitan City, to evaluate 12 images depicting types of men's skirts. First, the constituent image evaluation factors according to the constituent design elements of men's skirts were analyzed. Second, the differences in each constituent image evaluation factor based on the constituent design elements of men's skirt designs were analyzed. Third, the gender-based differences in image evaluation by men and women concerning the constituent design elements of men's skirt designs were analyzed. The analysis included relatively more women than men. The results of the image recognition dimension included the following categories: "attractive image," "evaluable image," "gender image," and "personality image." In modern fashion, skirts are used to express the diverse personalities of men's fashion. Thus, they are used beyond the stereotype of women's clothing, toward expanding and diversifying the image of men's clothing through mixing and creating a dichotomous image of men and women. It can be used as a design that suggests a gender-fluid image.