• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.5
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• pp.1057-1061
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• 2008

For the purpose of investigating the reasonable logics contained in physiognomy of east and old western medicine. hypothetical researches based on hydromechanics theory were performed concerning facial types of form and pathologic features, especially 4 types of Dr. Jisan-Essence, Qi energy. Emotional Activity and Blood(EQAB). In order to infer the functional relation between facial type forming and EQAB factors, EQAB were supposed as fluid grounded on their continual flowing or periodical change and pressure effect from its congestion. and a premise that there's a linear corresponding relationship between the appearance of organ and its physical conditions of its inner vessels is formed too. Through this work, the unit fluid model(UFM) of Essence can be assumed as circle shape formed by the high viscosity and surface tension, the UFM model of Qi energy as quadrangular shape by the scattering features to outer four directions, and the UFM of emotional activity as inverted triangular shape by the flippant and uprising features, and the UFM of blood as ellipsoid triangle by the heavy and descending features in spite of circulation. The shapes made from each UFM are reproduced in the process of human development and manifest respective facial shape through the self-reproduction method like fractal theory in the last. Conclusively. it is said that the facial form analysis method like EQAB type theory can be the useful methodology to understand the human pathological and physiological features in view of hydromechanics.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.140-141
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• 2018

There are three types of high fluidity concrete: powder based, VMA based, and combined. In the case of the powder based high fluidity concrete mixture, according to the textbook, increased viscosity due to the replaced fly ash can prevent segregation of coarse aggregate. On the other hand, decreased density of the powder due to the fly ash replacement can causes segregation but there is no report on this issue. Therefore, in this research, the segregation resistance and segregation evaluation method for powder based high fluid concrete mixture are evaluated. As a result, with increased replacing ration of supplementary materials, EIS value was decreased and apparently segregation resistance was increased. However, from the compressive strength evaluation depending on height of the cylindrical specimen, it was confirmed that the different of strength difference between top and bottom part of the specimen. Thus, following research regarding vertical segregation should be studied.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.1
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• pp.35-44
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• 2017

Supercavitation is one of the most attractive technologies to achieve high speed for underwater vehicles. However, the multiphase flow with high-speed around the supercavitating vehicle (SCV) is difficult to simulate accurately. In this paper, we use modified the turbulent viscosity formula in the Standard K-Epsilon (SKE) turbulent model to simulate the supercavitating flow. The numerical results of flow over several typical cavitators are in agreement with the experimental data and theoretical prediction. In the last part, a flying SCV was studied by unsteady numerical simulation. The selected computation setup corresponds to an outdoor supercavitating experiment. Only very limited experimental data was recorded due to the difficulties under the circumstance of high-speed underwater condition. However, the numerical simulation recovers the whole scenario, the results are qualitatively reasonable by comparing to the experimental observations. The drag reduction capacity of supercavitation is evaluated by comparing with a moving vehicle launching at the same speed but without supercavitation. The results show that the supercavitation reduces the drag of the vehicle dramatically.

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.118-126
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• 2014

The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for concrete pumping performance for the rapid construction of super-tall buildings. In this study, a quantitative evaluation of concrete fluid characteristics and surface friction resistance was performed, applying different concrete mix proportions and pumping conditions. To achieve this, we developed a temporary horizontal pumping evaluation system to measure pipe pressure and surface friction characteristics, and performed an experiment to investigate the relations between concrete rheology characteristics and friction resistance in pipe. The experiment found that in terms of the rheology characteristics, plastic viscosity was reduced remarkably after pumping. As well, high regression between the surface friction and pressure gradient was confirmed. This means that it is possible to evaluate the friction resistance between concrete and pipe by means of a pumping system that includes a frictional resistance testing pipe. In addition, high regression between the plastic viscosity of concrete after pumping and friction resistance coefficient was confirmed. Finally, it is considered that pumping pressure can be predicted using the friction resistance coefficient derived in this study, and it has high regression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.638-643
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• 2021

Oil is used in various industries, including the agricultural sector, food industry, and functional cosmetics. These oils are chemically unstable and prone to oxidation when exposed to oxygen, light, moisture, or high temperatures. Therefore, various attempts have been made to encapsulate them so that they are not exposed to such environments. When oil is injected into a refrigerant with greater density, the oil can be encapsulated as it rises due to buoyancy caused by the density difference. In this study, oil encapsulation was simulated to find the optimal conditions for operating equipment using computational fluid dynamics (CFD) for multiphase flows. Water or serum can be used as a refrigerant. The viscosity of water is relatively small, and if it is used as a refrigerant, oil droplets can be produced well even if oil and water are continuously injected in the equipment. However, the viscosity of serum is very high, and if it is used, the oil is stretched out and does not leave the nozzle. The results show that when using serum as a cooling medium, oil encapsulation is possible if the injection is stopped for some time after instantaneous injection at high speed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.333-334
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• 2002

Injection-compression molding parts are many cases with complicated boundary condition which is difficult to analysis of mold characteristics precisely. In this study, the effects of various process parameters such as multi-point gate location, initial charge volume, injection time and pressure have been investigated using finite element method to fomulate the melt front advancement during the mold filling process. A general governing equation for tracking the filling process during injection-compression molding is applied to volume of fluid method. To verify the results of present analysis, they are compared with those of the other paper. The results show a strong effect of processing conditions as a result of variations in the three-dimensional complex geometry model.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.277-282
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• 1989

Xanthan gum is a biopolymer produced by Xanthomonas campestris. In xanthan gum fermentation, the fermentation broth changes to highly viscous non-Newtonian fluid as xanthan gum concentration increases. Maximum xanthan gum concentration is limited by high viscosity of the broth since mass transfers of nutrient and oxygen are inhibited. Int this study the mass transfer effects were investigated in batch and fed-batch fermentations at various agitation speeds and by separate oxygen transfer experiments. Xanthan gum production rate was observed to be largely dependent on oxygen transfer coefficient; while cell growth rate was not affected highly by this factor.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.78-85
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• 2005

A numerical calculation is performed to study the effects of buoyancy force on the heat transfer characteristics of laminar forced convection flow in inclined parallel plates with the upper part cooled and the lower Part heated uniformly. Numerical results are presented for the Reynolds number ranges from $4.0\times10^{-3}$ to $1.13\times10^{-1}$. the angle of inclination, $\theta$. from 0 to 90 degree and Pr of the high viscosity fluid is 909. It is found that the flow pattern of mixed convection in inclined parallel Plates can be classified into four patterns which affected by Reynolds number and the angle of inclination.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.739-745
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• 2006

This paper presents a novel type of hybrid dispensing head for IC fabrication and surface mount technology. The proposed mechanism consists of solenoid valve and piezoelectric stack as actuators, and provides positive-displacement and jet dispensing. The positive-displacement dispensing can produce desired adhesive amount without viscosity effect, while the jet dispensing can produce high precision adhesive amount. In order to determine the relationship between required voltage of the piezoelectric actuator and needle displacement, both static and dynamic analysis are undertaken, In addition, finite element analysis is performed in order to find optimal design parameters. Dispensing flow rate and pressure in the chamber are evaluated through fluid dynamic model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.496-503
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• 2001

The suspension of the optical pickup actuator is damped by the presence of silicone rubber damper bond at its termination. In spite of the presence of it, the actuator still exhibits a strong mechanical resonance which affects its settling time and vibrational characteristics. This resonance can cause errors in reading information from the disk, particularly in high speed CD-ROM and DVD-ROM drives. Ferrofluids are stable colloidal suspensions of sub-micron sized magnetic particles in a carrier liquid. In the actuator design, ferrofluid is applied to the surface of the magnets until the quantity is sufficient to maintain intimate contact with the bobbin/carrier assembly. The fluid is retained in the magnetic field and its viscosity provides the desired mechanical damping to the moving assembly, improving the actuators settling time and vibrational characteristics. Access time is also improved, particularly on warped or eccentric discs.