• Nuclear Engineering and Technology
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• v.19 no.2
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• pp.85-98
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• 1987

To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.412-419
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• 2004

To investigate the utilization of calcium lactates (CaL) as coagulants for tofu manufacture, the quality characteristics and shelf-life of tofu made by CaL-P (black snail powder) and CaL-A (black snail ash) were investigated and compared to calcium chloride (CC), magnesium chloride (MC), calcium sulfate (CS ) and standard calcium lactate (CaL-S). And also, total microbe and turbidity of the tofu were determined during storage at 1$0^{\circ}C$. Coagulation ability of CaL-A was the highest, and the ability of CaL-P was higher than that of CaL-S. Yield of CaL-A tofu was similar to those of CS and CC tofu, while the yield of CaL-P tofu was 50% compared to that of CC. L＊ value of CaL-P tofu was lower, but a＊ and b＊ values were higher than those of other tofus. The hardness of tofu showed in the order of CaL-S>CS>CC>CaL-P>MC>CaL-A, while the cohesiveness showed in the order of MC>CaL-S>CC>CS>CaL-P>CaL-A. Calcium contents were 57 mg% in MC tofu, 174 mg% in CS tofu, 116 mg% in CaL-S tofu, 95 mg% in CaL-A tofu and 172 mg% in CaL-P tofu. From the results of microscopic observations, the lower hardness showed the more soft and the smaller particle. The particle of CaL-A tofu was small and uniformity but the size of CaL-P and CC tofu showed coarse. Sensory quality of CaL-P and -A tofu were better than the other tofu evaluated by texture, springiness, flavor and overall taste. The shelf-life estimated by total microbe was 4∼6 days in CC, MC, CS, CaL-S and CaL-A tofu, but 8 days in CaL-P tofu at 1$0^{\circ}C$. From the above results, the CaL-P and -A may believe to use as coagulant for tofu manufacture due to its softened taste and enhanced shelf-life, and higher calcium content which has higher absorbability in human body.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.31-41
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• 2011

To optimize the natural chemical agents against nuisance phytoplankton, we examined algal removal activity (ABA) of Plant-Mineral Composite (PMC), which already developed by our teams (Kim et al., 2010), on various conditions. The PMC are consisted of extracted-mixtures with indigenous plants (Camellia sinensis, Quercusacutissima and Castanea crenata) and minerals (Loess, Quartz porphyry, and natural zeolite), and characterized by coagulation and floating of low-density suspended solids. A simple extraction process was adopted, such as drying and grinding of raw material, water-extraction by high temperature-sonication and filtering. All tests were performed in 3 L plastic chambers varying conditions; six different concentrations ($0{\sim}1.0\;mL\;L^{-1}$), six light intensities ($8{\sim}1,400\;{\mu}mol\;m^{-2}s^{-1}$), three temperatures ($10{\sim}30^{\circ}C$), four pHs (7~10), five water depths (10~50 cm), and three different waters dominated by cyanobacteria, diatom, and green algae, respectively. Results indicate that the highest ABA of PMC was seen at $0.05\;mL\;L^{-1}$ in treatment concentrations, where showed a reduction of more than 80% of control phytoplankton biomass, while $1,400\;{\mu}mol\;m^{-2}s^{-1}$ in light intensity (>90%), $20{\sim}30^{\circ}C$ temperature (>60%), 7~9 in pH (>90%), below 50 cm in water depth (>90%), and cyanobacterial dominating waters (>80%), respectively. Over the test, ABA of PMC were more obvious on the algal biomass (chlorophyll-${\alpha}$) than suspended solids, suggesting a selectivity of PMC to particle size or natures. These results suggest that PMC agents can play an important role as natural agents to remove the nuisant algal aggregates or seston of eutrophic lake, where occur cyanobacterial bloom in a shallow shore of lake during warm season.