• KSTLE International Journal
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• v.1 no.2
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• pp.76-82
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• 2000

Turbulence in journal bearing operation is examined and the thermal variability is studied for isothermal, convective and adiabatic conditions on the walls under aligned and misaligned conditions. Also, the effects of a contraction ratio at the cavitation region and the mixing between re-circulating oil and inlet oil on the fluid field of oil film are included. An algorithm for the solution of the coupled turbulent Reynolds and energy equations is used to examine the effects of the various factors. Heat convection is found to play only a small role in determining friction and load under no mixing condition. However, under realistic mixing condition, the heat convection cannot be ignored. The wall temperature and heat transfer have been found to be of secondary important factors to the mixing effectiveness at the groove and the final mixture temperature.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.73-81
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• 1999

Shake mixing has been widely used in cell culture. The mixing performance for shake mixing, however, has not been reported quantitatively. The critical circulating frequency and the power consumption for complete suspension of particles, based on the definition of Zwietering, were measured in a shaking vessel containing a solid-liquid system. The critical suspension frequency was correlated by the equation from Baldi's particle suspension model modified with the physical properties of the particles. Critical suspension frequency was correlated as following ; $$N_{JS}={\frac{0.58\;d{_p}^{0.06}(g{\Delta}{\rho}/{\rho}_L)^{0.004}X^{0.03}}{D^{0.35}d^{0.17}{\upsilon}^{0.04}}}$$ The power consumption at the critical suspension condition in the shaking vessel was less than that in an agitated vessel with impeller.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.958-967
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• 2006

The overall objective of this research was to find out the role of rapid mixing conditions in the species of hydrolyzed Al(III) formed by Al(III) coagulants and to evaluate the distribution of hydrolyzed Al(III) species by coagulant dose and coagulation pH. When an Al(III) salt was added to water, monomers, polymers and solid precipitates may form. Different Al(III) coagulants (alum and PSOM) show to have different Al(III) species distribution over a rapid mixing condition. During the rapid mixing period, for alum, formation of dissolved AI(III) (monomer and polymer) increases, but for PSOM, precipitates of $Al(OH)_{3(S)}$ increases rapidly. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. The kinetic constants, Ka and Kb, derived from AI-ferron reaction. The kinetic constants followed very well the defined tendencies for coagulation condition. For pure water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values. Also, for raw water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_{3(S)}$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• Journal of the Korean Society of Combustion
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• v.22 no.3
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• pp.23-28
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• 2017

The fuel and oxidizer mixing process in the shock tube driven section is simulated numerically. The boundary condition is set based on an shock tube experimental condition. The objective is to predict the gas mixing time for experiments. In the experiment, the amount of fuel to be injected is determined in advance. Then, according to duration of fuel injection, 5 cases with the same fuel mass but different fuel mass flow rate are simulated. After fuel is injected into the driven section, the fuel and air will be mixed with each other through convection and diffusion processes. The mixing time is predicted numerically for experiments.

• 한국해양학회지
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• v.28 no.2
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• pp.121-131
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• 1993

The tidal front forming in the Mid-Yellow Sea off Korea, near Tae-An peninsular, is calculated using a 3-D general circulation model(Semtner, 1974) and the concept of mixing rate, an extension of the concept of mixing efficiency proposed by simpson & Hunter(1974). Along the north and south open boundaries, simple radiation conditions are applied. The model is run with the initial state which represents the winter condition. With imposed uniform heating by solar radiation and spatially-different vertical mixing, the model then generated the tidal front comparable to the observed one.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.111-116
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• 2004

An experiment was carried out to confirm the validity of time series evaluation of supersonic mixing condition by using catalytic reaction on a platinum wire. Geseous hydrogen was injected parallel to supersonic freestream (M$\infty$ $\approx$ 1.81) from a slit injector, which was located at backward facing step. Time series condition of supersonic mixing was evaluated by using W-type probe which has a platinum wire and reference wire (nickel wire). The evaluation was by simultaneously measuring each electric circuit which kept the temperature of wire constant. Investigations were also conducted for helium, air and no secondary injectant cases to compare with the hydrogen injectant case. The results indicated that it was possible to measure the time series behavior of air and hydrogen supersonic mixing layer or coherent motion of turbulence by using this evaluation.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.61-69
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• 1996

The combined wastewater of municipal landfill leachate and municipal sewage was treated using several sets of bench-scale aerated circulating system including porous media. Investigated items in this experiment were the dominant protozoa and metazoa in this system, the variation of microfauna relationship between operating condition and dominant genera. Also considered the factors determining dominant genera and their role. The outcome of this research is as follows; 1. Aspidisca, Vorticella, Truhellophyllum, Lecane, Philodina, Cyclops were mainly appeared prior to combinding leachate, while Trachelocerca, Bodo, Glaucoma were the dominant genera after combinding leachate. 2. As to metazoa, Nematode and Philodina were not influenced by 5oA leachate mixing ratio, meanwhile Crustacea has high sensitivity for increased leachate mixing ratio and it was not appeared in 5% leachate mixing ratio. 3. The appropriate treatability could'nt be expected at the above 10% leachate mixing ratio. Especially, in the condition of 20% leachate mixing ratio, all of the microfauna were affected damage seriously on their existence. Meanwhile hydraulic retention time, substrate loading rate and slut자e production rate didn't give notable influence on increasing the number of microfauna. 4. As to protozoa, saprozoic and holozoic species were appeared commonly and polysaprobic species were dominent. 5. Filamentous organsms were nearly not affected by leachate mixing. It seems that they could live without any trouble at the 10% leachate mixing ratio, if the substrate is sufficient. 6. Diversity of microfauna had a reducing trernd as the sewage was mixed with leachate.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.20-25
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• 1989

This study was carried out in order to investigate the treatment effect of PEG soln which is a common dimensional stabilizer to green log. sawing panel etc, on bonding product including plywood widely-used in secondary processing unit. The 30% concentration of aqueous PEG soln. with molecular weight of 400, 1.000 and 4,000 were prepared respectively, and also dipping the veneer in the PEG soln. spreading the PEG soln. on veneer and mixing the PEG soln. in the adhesive were allowed. Then the ratio of PEG impregnation on veneer, the adhesive strength of plywood were epitomized as follows: The ratio of impregnation by PEG 4,000 at dipping condition was highest. while that by PEG 400 at same condition was lowest. However, the effect of PEG molecular weight on the ratio of impregnation at spreading condition did not occur. 2. The adhesive strength was great in the order of 4,000>400>1,000 in molecular weight of PEG at dipping and spreading conditions. In case of mixing the PEG soln. in the adhesive, the adhesive strength was great in the order of 400>1,000>4,000 in molecular weight of PEG. Throughout three treatment conditions, PEG 400 was relatively favourable with about 10kg/$cm^2$ dry strength. 3. The adhesive strength was great 10 the order of spreading >dipping >mixing condition. 4. Although adhesive strength with the 30% concentration of aqueous PEG soln. was decreased by 35% and over, compared to control (non-treatment) adhesive strength, all types of PEG treatment except mixing the PEG soln. in the adhesive exceeded the standard dry strength for common use panel. 7.5kg/$cm^2$. 5. In warm water-proof test, the adhesive strengths by all PEG treatment conditions were less than the standard wet strength, 7.5kg cot, and also delamination of glue line occured mostly in mixing in the PEG soln. in the adhesive condition.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.141-146
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• 1999

An experimental study is carried out to estimate the effects of mixing and placing condition on the mechanical properties of anti-washout concrete. According to the test results, mixing method and placing temperature do affect the characteristics of rrsh concrete, while they do not affect the strength development of anti-washout concrete. But, concrete strength was greatly affected by the placing condition and placing height. Concrete strength decreases linearly as the placing height increased. Compared to the normal concrete, the increase in strength is not associated much with an increase in the elastic modulus of anti-washout concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.9-10
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• 2017

In case of the concrete is poured into the HPC(Hollow Precast Concrete) column, the shrinkage condition of the HPC surface and the infilled concrete may be different, causing an interfacial space and deteriorating the integration performance. In this study, manufacturing HPC column mold and and the drying shrinkage properties with the charging concrete were examined. As a result, case of the shrinkage reducing agent showed the best drying shrinkage reduction effect. In the case of the expansive agent, the length change was lower than that of plain, but the difference from the shrinkage reducing agent was large, so it is considered that mixing condition of expansion mixing condition should be improved.