• New & Renewable Energy
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• v.1 no.2 s.2
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• pp.60-72
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• 2005

The effect of alkaline pre-treatment on the solubilization of waste activated sludge(WAS) was investigated, and the biodegradability of WAS, pretreated WAS, [PWAS], food waste and two types of mixture were estimated by biochemical methane potential [BMP] test at $35^{\circ}C$. The biodegradability of PWAS and mixture waste were significantly improved due to the effect of alkaline hydrolysis of WAS. An alkaline pre-treatment was identified to be one of the useful pre-treatment for improving biodegradability of WAS and mixture waste. In high-rate anaerobic co-digestion system coordinate with an alkaline pre-treatment in process, the digesters were operated at the HRT of 5, 7, 10 and 13 days with a mixture of FW $50\%\;and\;PWAS\;50\%,\;$In term of $CH_4$ content, VS removal and specific methane production [SMP] which are the parameters in the performance of digester, the optimum operating condition was found to be a HRT of 7 days and a OLR of 4.20g/L-day with the highest SMP of 0.340 L $CH_4/g$ VS.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.67-72
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• 2000

A special double drier structure at a plant level is developed to recycle old ascon as well as an economic mixture rate of old with new is analyzed under safety consideration in this thesis. Based upon the experimentations performed throughout this research, 35% of old ascon mixture is found to be the best for flow test, stability, air void, density, and moisture susceptibility. It is also found that mixture does not meet the requirement in indirect tensile test, However, it is concluded that it is not critical at all since the experimental results present that the difference is too small to give any meaningful indication. A good return for the investment of this facility can be obtained if the mixture rate guideline suggested in this research is kept.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.11a
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• pp.471-482
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• 2000

A special double drier structure at a plant level is developed to recycle old ascon as well as an economic mixture rate of old with new is analyzed under safety consideration in this thesis. Based upon the experimentations performed throughout this research, 35% of old ascon mixture is found to be the best for flow test, stability, air void, density, and moisture susceptibility. It is also found that the mixture does not meet the requirement in indirect tensile test, However, it is concluded that it is not critical at all since the experimental results present that the difference is too small to give any meaningful indication. A good return for the investment of this facility can be obtained if the mixture rate guideline suggested in this research is kept.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.231-237
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• 2016

This article reports a new chemical bath for preparing a mirror-like surface of AZ31 Mg alloy. In order to find an appropriate chemical polishing solution, four different acidic solutions of sulphuric acid, nitric acid, acetic acid and a specially designed mixture of nitric acid and acetic acid were investigated in view of the changes in surface appearance, roughness and dissolution rate of AZ31 Mg alloy. The surface scales on AZ31 Mg alloy were readily removed by all the acidic solutions, but a reflective surface was produced only by etching in the specially designed solution, and only after a specific etching time. The surface roughness increased with etching time in sulphuric acid, nitric acid, and acetic acid, but it lowered after a specific etching time in the specially designed mixture of nitric acid and acetic acid. Dissolution rate of the alloy in the specially designed mixture of nitric acid and acetic acid appeared to be more than twice than that in separate nitric acid or acetic acid. In this work, we recommend the mirror-like surface of AZ31 Mg alloy obtained by polishing for an optimum time in a mixture of nitric acid and acetic acid for following surface finishings, chemical conversion coating, electroplating, electrophoretic painting and anodizing treatment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1393-1400
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• 2003

Ignition of hydrogen and oxygen in the "third limit" is theoretically investigated in the stagnation point flow with activation energy asymptotics. With the steady-state approximations of H, OH, O and HO$_2$, a two-step reduced kinetic mechanism is derived for the regime lower than the crossover temperature T$_{c}$ at which the rates of production and consumption of all radicals are equal. Appropriate scaling of Damkohler number successfully provides the explicit relationship between pressure, temperature and strain rate at ignition. It is shown that, compared with those for the counterflow, ignition temperatures for the stagnation point flow are considerably increased with increasing the system pressure. This is because ignition in the "third limit" is characterized by the production of reduction of $H_2O$$_2$, which is reduced by wall effect. Strain rate substantially affects ignition temperature because key reaction rates of $H_2O$$_2$ are comparably with its transport rate, while the mixture temperature and the hydrogen composition do not significantly affect ignition temperature.e.

• Journal of Hydrogen and New Energy
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• v.24 no.4
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• pp.334-339
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• 2013

In this study, as a candidate of the carbon dioxide ($CO_2$) absorbents, the mixture solution of polyethylene glycol dimethyl ether (PEGDME) and tetrahydrofuran (THF) were investigated. $CO_2$ absorption rate was measured by using high pressure $CO_2$ screening equipment in the range of 1 - 10wt% THF. Absorption capacity of the mixture solution was also estimated. Based on the results, we found that mixture solution containing THF had higher absorption rate and $CO_2$ loading capacity compared to PEGDME at $25^{\circ}C$.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.737-746
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• 2008

Numerical study is conducted to grasp preferential diffusion effects on flame characteristics in $H_2/CO$ syn-gas diffusion flames diluted with $CO_2$. The models of Sun et al. and David et al., which have been well known to be best-fitted for $H_2/CO$ synthetic mixture flames. are evaluated for $H_2/CO$ synthetic mixture flames diluted with $CO_2$. Comparison of flame structures with mixture-averaged species diffusion and suppression of the diffusivities of $H_2$ and H was made. The behaviors of maximum flame temperatures with those species diffusion models are not explained by scalar dissipation rate but by the nature of chemical kinetics. Importantly-contributing reaction steps to heat release rate are also compared for the three species diffusion models in $H_2/CO/CO_2$ flames with and without $CO_2$ dilution.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.135-142
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• 2001

Compostable household wastes(mainly food wastes), after waste papers and cardboard being removed, were daily fed into small bins and mixed thoroughly while the air was supplied into the bin. Three small bins were employed: in case I, only recycled compost was composted, after being once fed at the beginning of composting, in case II, compostable household wastes(less than 50 mm) torn roughly by the hands with recycled compost, and in case III, compostable household wastes(less than 2 mm) ground by a kitchen mixer for vegetables with recycled compost. The straight-line was maintained between the wet or the dry residual mass of composting mixture versus composting time date(the coefficient of determination $R^2{\geq}0.98$ for the wet and $R^2{\geq}0.90$ for the dry). The decomposition rate of each composted material was estimated during composting. The total weight reduction rate after 30 days was 67.86% and 66.14% for case II and III, respectively. For case II, the daily weight reduction 6.82% and the daily decomposition rate 8.81% with the composting mixture, but the daily weight reduction rate was 56.43% and the daily decomposition rate 19.26% with only compostable household wastes. For case III, the daily reduction rate was 6.93% and the daily decomposition rate 7.70% with the composting mixture, but the daily weight reduction rate was 53.30% and the daily decomposition rate 22.95% with only compostable household wastes. The physicochemical characteristics of composting mixture did not show much difference between case II and III as was expected.

• Journal of Life Science
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• v.26 no.7
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• pp.805-811
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• 2016

The present study was performed to evaluate the anti-oxidant and anti-proliferating activity of the water extract mixture of Cordyceps militaris (CM) and Allium tuberosum (AT). The water extract mixture rate of CM and AT was optimized by means of a sensory evaluation test. The optimized mixture rate were decided at 70% of CM, 30% of AT, and 10% of apple concentrate as an additive. The values of total acidity, pH, sugar contents, and turbidity of the water extract mixture were 0.1%, 4.28, 9.10 °Brix, and 1.48 respectively. The water extract mixture had effective DPPH radical scavenging activity, reducing power effect, and ABTS radical activity. DPPH radical activities of the water extract and the water extract mixture were 43.2% and 51.7% respectively; their reducing power (OD₇₀₀) was 1.14 and 1.43 respectively; and ABTS^.+ radical activities were 47.1% and 62.2% respectively. Also, the water extract mixture showed a higher anti-proliferating effect than the AT extract on human prostate cancer cells. These results provided experimental evidence that the water extract mixture of CM and AT is a better source of anti-oxidant and anti-cancer ingredients than a single extract of CM. In conclusion, the water extract mixture of CM and AT will be beneficial in development of a functional drink.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.152-159
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• 2017

For the effective seedling production of the hard shelled mussel, Mytilus coruscus, this study assessed the effects of the dietary value of live food, density, water temperature and salinity on growth and survival rate of the larvae. The optimal survival rate and growth rate were examined under differing conditions of water temperature, salinity, and rearing density for 30 days. The three groups were provided different feeding organisms, such as Isochrysis galbana and Teleaulax suecica. The mixtures were provided at a rate of $5{\times}10^4cell\;mL^{-1}$. The best growth was observed in the group with conditions $21^{\circ}C$ water temperature ($16.2{\pm}9.1{\mu}m$), 33 psu of salinity ($16.82{\pm}3.9{\mu}m$), $2500individual\;m^{-2}$ ($17.2{\pm}5.9{\mu}m$), and fed with $5{\times}10^4cell\;mL^{-1}$ of I. galbana and T. suecica mixture ($16.0{\pm}7.3{\mu}m$). The highest survival rate was found in the group at conditions $18^{\circ}C$ water temperature (66.4%), 33 psu of salinity (24.4%), $2500individual\;m^{-2}$ (65.8%), and fed with $5{\times}10^4cell\;mL^{-1}$ of I. galbana and T. suecica mixture (58.8%). We therefore conclude that the suitable culture conditions for the stable production of hard shelled mussel artificial seedlings was at 18 to $21^{\circ}C$ of temperature, 30 to 33 psu of salinity, 2500 to $5000individual\;m^{-2}$ of rearing density, and feeding supplement of $5{\times}10^4cell\;mL^{-1}$ of I. galbana and T. suecica mixture under semi running water system.