• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4726-4731
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• 2011

This paper proposed the algorithm to select optimal grinding condition for plunge grinding in the batch production unit. In order to apply to the proposed algorithm, the state variable for plunge grinding process was defined and the optimal grinding condition for each cycle in batch production was decided by genetic algorithm. Based on the optimized grinding condition in each cycle, the optimal grinding condition for whole batch production was selected by dynamic programming. The proposed algorithm was evaluated by computer simulation.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.2
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• pp.83-88
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• 2017

Silk is appealing materials for many biomedical applications involving tissue engineering and implantable devices, because of its biocompatibility, environmental stability, controlled proteolytic biodegradability and morphologic flexibility. Silk matrix is required for the treatment of a wide wound area, but the present silk matrix is made by the second processing, and thus, the labor and the cost are high. In this work, we investigated the optimal production condition of natural silk 3D matrix using the silkworms and invented Automatic Silk Matrix Making Machine (ASMMM) for natural silk 3D matrix production. As a result, we determined that optimal production condition for making A4 paper size natural silk 3D matrix was used Rough aquarelle paper on surface at $25^{\circ}C$ and 30 silkworm larvae. These results are expected to provide basic data for the efficient production of the natural silk 3D matrix, and it is suggested that the produced natural silk 3D matrix is useful as a medical biomaterials.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.6
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• pp.113-126
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• 1992

Recently the multi-kind, small-amount manufacturing system has been replacing the mass manufacturing system, and domestic machining inustry also is eager to absorb the new technology because of its high productivity and cost reduction. The optimization of the cutting condition has been a vital problem in the machining industry, which would help increase the productivity and raise the international competitiveness. It is intended in this study to investigate the machining costs per unit time which is essential to the analysis of the optimal cutting condition, to computer the cutting speed that lead to the minimum machining costs and the maximum production to suggest the cutting speed range that enables efficient speed cutting, and to review the machining economy in relation to cutting depth and feed. Also considered are the optimal cutting speed and prodution rated in rrelation with feed. It is found that the minimum-cost cutting speed increases and the efficient cutting speed range is reduced as machining cost per unit time increases since the cutting speed for maximum production remains almost constant. The machining cost is also lowered and the production rate increases as the feed increases, and the feed should be selected to satisfy the required surface roughness. The machining cost and production rate are hardly affected by the cutting depth if the cutting speed stays below 100m/min, however, they are subject to change at larger cutting depth and the high-efficient speed range also is restricted. It can be established an adaptive optimal cutting conditions can be established in workshop by the auto-selection progam for optimal operation. It is expected that this method for choosing the optimal cutting conditions might contribute to the improvement of the productivity and reduced the cost. It is highly recommended to prepare the optimal cutting conditionthus obtained for future use in the programing of G-function of CNC machines. If proper programs that automatically select the optimal cutting conditions should be developed, it would be helpful to the works being done in the machine shops and would result in noticeable production raise and cost reduction.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.111-117
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• 2002

In most machining companies, operators decide the cutting condition, a pair of spindle speed (5) and table federate (F) by experience and subjective judgment. As cutting conditions are determined by operators' experience and ability, inconsistent cutting conditions are given in same operating conditions. The objective of this study is to develop the cutting condition decision system which utilizes shop data and predicts tool life by neural network and eventually leads to the optimal cutting condition. The production time per piece is considered for an optimization object. We will discuss the process of an optimal cutting condition decision by neural network. By this process, a series of shop data is stored. And neural network is constructed for prediction of tool life and the optimal cutting condition is recommended from a cutting condition decision system using the stored shop data. The results show that the developed system is rational in searching the optimal cutting conditions on job operations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.572-577
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• 2002

We investigated the optimal condition for production of bacterial cellulose with Gluconacetobacter persimmonus KJ145. For bacterial cellulose production, optimal medium composition and culture conditions were conducted to determine. Apple juice (10$^{\circ}$Brix) medium was suitable than Hestrin & Schramm medium which is generally used for the bacterial cellulose production. When 1% pyruvate as carbon source was added to apple juice, bacterial cellulose production rose to high level. The effect of various nitrogen sources was investigated: CSL was found to be essential to high cellulose yields and the optimal CSL concentration was 10%. Optimal temperature and culture time for the bacterial cellulose production was 35$^{\circ}C$ and 16 days, respectively At the optimal condition Gluconacetobacter persimmonus KJ145 produced 8.96g/L of bacterial cellulose (dry weight), which was much higher than reported values.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.220-228
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• 1995

For polyhydroxyalkanoic acid (PHA) production, several microorganisms were isolated from sewage sludge. One of them, GB-77 strain, was chosen from its PHB/HV copolymer production on only fructose without cosubstrate. The isolated strain GB-77 was identified as the genus Alcaligenes. Optimal temperature and pH for cell growth were 36C and 6.8. Optimal medium composition was 10 g/l of fructose and 5 g/l of polypeptone, 1 $\times$ 10$^{-2}$M Na$^{2}$HP0$^{4}$, 1.3 $\times$ 10$^{-2}$M KH$^{2}$PO$^{4}$. To investigate the optimal condition for polyhydroxyalkanoic acid production two-stage culture technique was used; first stage for cell growth and second stage for PHA production on unbalanced growth conditions. Optimal conditions for high PHA production were C/N ratio 50, temperature 36$\circ$C and pH 6.8. To overcome fructose inhibition on cell growth, intermittent feeding fed-batch culture technique was used. Total cell concentration was 17.4 g/l with 9.1 g/l of PHA. The purified PHA was identified PHB/HV copolymer by NMR analysis.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.525-528
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• 2001

The purpose of this study is to looking for the optimal condition of methane production enhancement. The conditions tested for increasing methane production were temperature. pH. and various carbon sources including methanol. formic acid. sodium acetate. succinic acid. and glucose. As a result, optimal temperature was 55 .C and optimal pH was around neutral condition. And methanol seemed to be best carbon source which can drastically increase methane production.

• Environmental Engineering Research
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• v.20 no.2
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.

• Journal of environmental and Sanitary engineering
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• v.5 no.2
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• pp.103-110
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• 1990

For production of thermophilic and alkaline protease, Bacillus sp. strain AP-5 was isolated from a compost. The production of the protease was reached at maximum for 4 days at $55^{\circ}$ in standing culture. Chitin and Cellulose as carbon source, and Skim Milk as nitrogen source were favorable for the production of the enzyme. Optimal temperature and optimal pH of the enzyme was $55^{\circ}$ and 11, respectively. Metal ion didn't effect on the enzyme activity, the protease was very stable at heat treatment of 30 min at $55^{\circ}$.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.92-99
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• 2012

The optimal physical factors affecting enzyme production in an airlift fermenter have not been studied so far. Therefore, the physical parameters such as aeration rate, pH, and temperature affecting PLA-degrading enzyme production by Actinomadura keratinilytica strain T16-1 in a 3 l airlift fermenter were investigated. The response surface methodology (RSM) was used to optimize PLA-degrading enzyme production by implementing the central composite design. The optimal conditions for higher production of PLA-degrading enzyme were aeration rate of 0.43 vvm, pH of 6.85, and temperature at $46^{\circ}C$. Under these conditions, the model predicted a PLA-degrading activity of 254 U/ml. Verification of the optimization showed that PLA-degrading enzyme production of 257 U/ml was observed after 3 days cultivation under the optimal conditions in a 3 l airlift fermenter. The production under the optimized condition in the airlift fermenter was higher than un-optimized condition by 1.7 folds and 12 folds with un-optimized medium or condition in shake flasks. This is the first report on the optimization of environmental conditions for improvement of PLA-degrading enzyme production in a 3 l airlift fermenter by using a statistical analysis method. Moreover, the crude PLA-degrading enzyme could be adsorbed to the substrate and degraded PLA powder to produce lactic acid as degradation products. Therefore, this incident indicates that PLA-degrading enzyme produced by Actinomadura keratinilytica NBRC 104111 strain T16-1 has a potential to degrade PLA to lactic acid as a monomer and can be used for the recycle of PLA polymer.