• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.354-359
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• 2009

The productivity of ultra-small rotifer, Synchaeta kitina was investigated at the exchange rate of culture water (10, 20, 30, 40 and 50%) and initial inoculation densities (250, 600 and 900 inds. per mL) in semi-continuous culture. Also, the possibility of mass culture was investigated in a 100 L culture tank. Tetraselmis suecica was used as the feed for S. kitina in all experiments. The production of S. kitina increased with an increase in exchange rate of culture water. The highest production ($82.0{\times}10^5$ inds.) was achieved at 40% exchange rate of culture water. The production of S. kitina increased with an increase of initial inoculation density during the first week and the highest total production ($17.4{\times}10^6$ inds.) was achieved at 900 inds. per mL of initial inoculation density. However, on the second week, all treatments were not significantly different in total production (P>0.05). During the two weeks, total production of S. kitina at 900 inds. per mL of initial inoculation density was higher than at 600 inds. of initial inoculation density, but there was no significant difference (P>0.05). In the 100 L culture tank, density of S. kitina was kept from 516 to 890 inds. per mL and S. kitina was daily harvested $15.5{\times}10^6$ to $26.7{\times}10^6$ during the experimental period. The production cost for 100 million rotifers in semi-continuous culture was 63,656 won. The results from this study indicate that the optimal exchange rate of culture water and initial inoculation density for the semi-continuous culture of ultra-small rotifer, S. kitina are 40% and 600 inds. per mL, respectively.

• Journal of Electrochemical Science and Technology
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• v.15 no.3
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• pp.388-404
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• 2024

In the present work, the operating parameters were optimized using Box Behnken Design (BBD) in response surface methodology (RSM) to maximize the hydrogen production rate (R₁) and hydrogen production rate per unit watt consumed (R₂) of a proton exchange membrane electrolysis cell (PEMEC), a third response (R₃) which was the sum of the scaled values of R₁ and R₂ were selected to be maximized so that both hydrogen production rate and hydrogen production rate per unit watt consumed could be maximized. The major parameters which were influencing the experiment for enhancing the output responses were oxygen electrode/anode electrocatalyst loading (A), current supplied (B) and water inlet temperature (C). The commercial proton exchange membrane Nafion^® was used as the electrolyte. The acetylene black carbon (C_AB) supported IrO₂ was used as the electrocatalyst for preparing oxygen electrode/anode whereas commercial Pt (40 wt%)/C_HSA was used as the H₂ electrode/cathode electrocatalyst. The quadratic model was developed to predict the output/ responses and their proximity to the experimental output values. The developed model was found to be significant as the P values for both the responses were < 0.0001 and F values were greater than 1. The optimum condition for both the responses were O₂ electrode/anode electrocatalyst loading of 1.78 mg/cm², supplied current of 0.33 A and water inlet temperature of 54℃. The predicted values for hydrogen production rate (R₁) and hydrogen production rate per unit watt consumed (R₂) were 2.921 mL/min and 2.562 mL/(min·W), respectively obtained from the quadratic model. The error % between the predicted response values and experimental values were 1.47% and 3.08% for R₁ and R₂, respectively. This model predicted the optimum conditions reasonably in good agreement with the experimental conditions for the enhancement of the output responses of the developed PEM based electrolyser.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.990-996
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• 2005

The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y$\alpha$) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y$\alpha$ and lag time in total gas has showed significant (p<0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p<0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y$\alpha$ indicated that the effect of diet on Y$\alpha$ was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y$\alpha$, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.

• The Korean Journal of Ecology
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• v.9 no.4
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• pp.185-192
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• 1986

The production and decomposition rate of litters from the three different locations, Quercus acutissium forest at 630 m, Q. mongolica forests at 1, 005m and 1, 490 m of Mt. Dokyoo, were estimated by Olson model. The contents of N, P, K, Ca and Na in soils were measured and the relationships among them were elucidated. The amounts of litter production in Q. mangolica were the lowest, 378.96g/$m^2$ at 1, 490 m and the highest, 876.12g/$m^2$ at 1, 005 m. And the amounts of litter production in Q. acutissima at 630 m was 686.16 g/$m^2$. The decay rate of litters in Q. mongolica was the smallest, 0.123 at 1, 490 m, and the largest, 0.222 at 1, 005 m. And that in Q. acutissima was 0.169 at 630 m which was the medium rate. The production and decay rate of litters decreased with the ascending altitude. The values at 630 m were maller than those at 1, 005 m. This might be due to the fact that the tree species at 630 m was Q. acutissima was 0.169 at 630 m which was the medium rate. The production and decay rate of litters decreased with the ascending altitude. The values at 630 m was Q. acutissima which was different from Q. mongolica at 1, 005 m and 1, 490 m. The half-0life of litter decay in Q. monglica was 5, 634 years at 1, 490 m and 3.134 years at 1, 005 m. And that in Q. acutissima was 4.132 years at 630 m. The decay rates of litters were tend to be inversely proportional to the ascending altitude. The annual standing stocks of mineral and their amounts returned to the soil were proportional to the decay rate of organic matters.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.326-329
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• 2004

Corynebacterium acetoacidophilum RYU3161 was cultivated in a L-histidine-limited fed-batch culture. To investigate the effect of cell growth on the L-proline production, 5 L fed-batch culture was performed using an exponential feeding rate to obtain the specific growth rates $(\mu)$ of 0.04, 0.06, 0.08, and 0.1 $h_1$. The results show that the highest production of L-proline was obtained at $\mu$ = 0.04 $h_1$. The specific L-proline production rate $(Q_p)$ increased pro-portionally as a function of the specific growth rate, but decreased after it revealed the maxi-mum value at $\mu$ = 0.08 $h_1$. Thus, the highest productivity of L-proline was 1.66 g $L^-^1 h^-^1$ at $\mu$ = 0.08 $h_1$. The results show that the production of L-proline in C. acetoacidophilum RYU3161 has mixed growth-associated characteristics.

• Asian Journal of Turfgrass Science
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• v.11 no.1
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• pp.33-43
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• 1997

The production and decomposition rate of litters of major forest trees in Korea, such as Quercus acutissima, Quercus mogolica Robinia pseudoacacia Pinus rigida, Pinus thunbergiana, Abies koreana,Phy'llostackys reticulata, were estimated by Olson model. The amount of mineral nutrients in litters and soil were measured, and the relationships among them were studied. The annual litter production was the most in the forest of broadleaved deciduous trees and the least in the forest of monocotyledonous trees. The decomposition rate of broadleaved deciduous litters was higher than that of coniferous litters and lower than that of R. pseudoacacia litters. The time required for the decomposition of half of the accumulated organic matter of R.pseudoacacia litter, Quercus litter, P. rigida litter, Ph. reticulata litter, P. thunbergiana litter and .4.koreana litter in the forest stands were 1.263 years, 2.290~2.365 years, 2.644 years, 4.660 years,4.750 years, 6.699 years respectively. The amounts of N in litters and the amounts of N returned to the soil in the forests of R. pseudoacacia. Quercus, Pinus were proportional to the decay rate of organic matter. Key words: Annual litter production, Decomposition rate.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.33-40
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• 2013

Purpose: The goal of this study was to build an accurate digital factory that evaluates the performance of a factory using computer simulation. To achieve this goal, we evaluated the effect of worker-related variables on production in a simulation model using comparative analysis of two cases. Methods: The overall work process and worker-related variables were determined and used to build a simulation model. Siemens PLM Software's Plant Simulation was used to build a simulation model. Also, two simulation models were built, where the only difference was the use of the worker-related variable, and the total daily production analyzed and compared in terms of the individual process. Additionally, worker efficiency was evaluated based on worker analysis. Results: When the daily production of the two models were compared, a 0.16% error rate was observed for the model where the worker-related variables were applied and error rate was approximately 5.35% for the model where the worker-related variables were not applied. In addition, the production in the individual processes showed lower error rate in the model that included the worker-related variables than the model where the worker-related variables were not used. Also, among the total of 22 workers, only three workers satisfied the IFRS (International Financial Reporting Standards) suggested worker capacity rate (90%). Conclusions: In the daily total production and individual process production, the model that included the worker-related variables produced results that were closer to the real production values. This result indicates the importance of worker elements as input variables, in regards to building accurate simulation models. Also, as suggested in this study, the model that included the worker-related variables can be utilized to analyze in more detail actual production. The results from this study are expected to be utilized to improve the work process and worker efficiency.

• Journal of the Korean Society of Safety
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• v.10 no.1
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• pp.9-19
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• 1995

The recent development of NC lathe and machining renter have enabled automatic or unmanned manufacturing system for the improvement of production rate. And if you want to introduce automatic or unmanned manufacturing system into the cutting process of cage motor rotor, the selections of effective cutting conditions, rational tool grades and tool angles are necessary. As a result, the selection of cutting conditions, tool grades and tool angles are important factors to production rate.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.46-55
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• 1995

The recent development of NC lathe and machining center have enabled automatic or unmanned manufacturing system for the improvement of production rate. And if you want to introduce automatic or unmanned manufacturing system into the cutting process of cage motor rotor, the selections of effective cutting conditions, rational tool grades and tool angles are necessary. As a result, the selection of cutting conditions, tool grades and tool angles are important factors to production rate.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.245-248
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• 2003

As a result of broth substitutions when each culture-mediums were difference, whole culture-medium was found to be best feeding solution for production of PS-7 by B. indica. Maximal production of PS-7 was 1$10.0\;g/{\ell}$ and its conversion rate from 2% (w/v) glucose to PS-7 was 50%. After 48 hr, 50%(v/v) medium of working volume began to substitute in 7L jar fermenter. Production of PS-7 increased after 48hr, recovered productivity of PS-7. Following this preliminary culture, the resultant culture was subjected to continuous flow conditions controlled that the dilution rate were $0.01\;{\sim}\;0.04\;h^{-1}$. Production of PS-7 increased at dilution rate $0.0100\;h^{-1}$ whereas productivity of PS-7 decreased gradually in dilution rate $0.0200\;{\sim}\;0.0400\;h^{-1}$. Maximal production of PS-7 was $10.0\;g/{\ell}$ in continuous culture.