• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.65-66
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the new FF 6th stage automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new FF 6th speed automatic transmissions' output gear. The gear noise was dramatically disappeared and the process and results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.665-671
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new automatic transmissions' gear. The gear noise was dramatically disappeared and the process and the results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• Food Engineering Progress
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• v.14 no.3
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• pp.217-221
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• 2010

Various conditions of acetic acid fermentation by Acetobacter aceti B20 strain were investigated and evaluated to optimize the fermentative production of acetic acid. The effects of the initial ethanol concentration on growth and acid productivity in a flask and fermentor were also studied. The growth of A. aceti B20 strain was inhibited as the concentration of ethanol increased. However, the highest total acidity and fermentation yield were 5.34% and 56.1%, respectively when the initial concentration of ethanol was 7% in the batch fermentation. Although the concentration of initial glucose influenced the growth rate of B20 strain, it did not influence the total acidity in the flask culture. When the agitation speed increased, the growth, total acidity and fermentation yield were all improved. In fed-batch fermentation, total acidities and fermentation yields were 7.14-8.76% and 39.1-53.0%, respectively, and their values mostly depended on the feeding methods.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.131.1-131.1
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• 2010

This study was conducted for engineering optimization for the gasification process which is the key factor for success of Taean IGCC gasification plant which has been driven forward under the government support in order to expand to supply new and renewable energy and diminish the burden of the responsibility for the reduction of the green house gas emission. The gasification process consists of coal milling and drying, pressurization and feeding, gasification, quenching and HP syngas cooling, slag removal system, dry flyash removal system, wet scrubbing system, and primary water treatment system. The configuration optimization is essential for the high efficiency and the cost saving. For this purpose, it was designed to have syngas cooler to recover the sensible heat as much as possible from the hot syngas produced from the gasifier which is the dry-feeding and entrained bed slagging type and also applied with the oxygen combustion and the first stage cylindrical upward gas flow. The pressure condition inside of the gasifier is around 40~45Mpg and the temperature condition is up to $1500{\sim}1700^{\circ}C$. It was designed for about 70% out of fly ash to be drained out throughout the quenching water in the bottom part of the gasifier as a type of molten slag flowing down on the membrane wall and finally become a byproduct over the slag removal system. The flyash removal system to capture solid particulates is applied with HPHT ceramic candle filter to stand up against the high pressure and temperature. When it comes to the residual tiny particles after the flyash removal system, wet scurbbing system is applied to finally clean up the solids. The washed-up syngas through the wet scrubber will keep around $130{\sim}135^{\circ}C$, 40~42Mpg and 250 ppmv of hydrochloric acid(HCl) and hydrofluoric acid(HF) at maximum and it is turned over to the gas treatment system for removing toxic gases out of the syngas to comply with the conditions requested from the gas turbine. The result of this study will be utilized to the detailed engineering, procurement and manufacturing of equipments, and construction for the Taean IGCC plant and furthermore it is the baseline technology applicable for the poly-generation such as coal gasification(SNG) and liquefaction(CTL) to reinforce national energy security and create new business models.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.2
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• pp.122-128
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• 2023

The target must be located within the main-lobe of the antenna in order to measure the direction of the target by using sum-delta monopulse technique. The most common way if the target is located within the main-lobe is to compare the amplitude of the sum channel received signal with the delta channel received signal. However, in the case of the single-ring circular array antenna, it is difficult to apply the conventional method due to its structural limitation where antenna elements do not exist in the center of the array. In this paper, we proposed a novel method to identify whether a target is located within the main-lobe by appropriately adjusting the feeding amplitude of each element constituting the single-ring circular array antenna through the particle swarm optimization method. Simulation results showed that the proposed method can determine whether the target is located within the main-lobe of the single-ring circular array antenna.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.32-35
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• 1999

Addition of ${\beta}$-cyclodextrin (${\beta}$-CD) polymer during the biotransformation of digitoxin into digoxin using cell suspension cultures of Digitalis lanata enhanced the conversion yield. Digitoxin showed better adsorption to CD polymer compared to digoxin, so that the optimization of addition time was found to be necessary. In the case of adding CD polymer 24 hours after the feeding of substrate digitoxin, the highest digoxin production could be achieved. At this period, digitoxin was almost consumed by cells and productivity was proportionally enhanced according as the amount of substrate was increased. Immobilization of CD polymer did not promote the biotransformation. When 3.33 g/L of CD selective inclusion complex formation could be expected. Adsorption rate was found to be rapid and saturation was obtained within 10 hours of contact.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.194-197
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• 2004

In the tube hydroforming process, a tube is placed into the die cavity and the ends of the tube are sealed by fixing the axial cylinder piston into the ends. Then the tube is pressurized with a hydraulic fluid and simultaneously the axial cylinders move to feed the material into the expansion zone. Therefore, the quantitative relationship between process parameters such as internal pressure and feeding amount and hydroformabillity, is hard to establish because of their high complexity and many unknown factors. In this study, the empirical and the quantitative relationship between process parameters and hydroformabillity are analyzed by fuzzy rules. Fuzzy expert system is an advanced expert system which uses fuzzy rule and approximate reasoning. Many process parameters are converted to the quantitative relationship by use of approximate reasoning of fuzzy expert system. The comparison between experimentally measured hydroformabillity from hydroforming experiments and the predicted values by fuzzy expert system shows a good agreement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.127-131
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• 2006

An optimization algorithm is applied to a calibration task. In this paper, test data correlation, a reverse analysis method, is presented. With this method, flow rate and heat transfer rate, which are difficult to be measured are estimated using measured pressure and temperature data for helium pressurization system of launch vehicle.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.395-398
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• 2006

this paper provides a novel method to start the linear engine coupled linear generator from dead stop to its final steady state operation. This method depends mainly to use the linear generator mounted on the shaft of the linear engine to provide the required thrust force to move and oscillate the linear engine from bottom to top dead centers. It is a cost effective approach to start the internal linear combustion engine using its coupled tubular permanent magnet linear generator proposed here. This linear generator operates in this case in motoring mode, providing the required thrust force by feeding this linear generator phases with currents by using a three phase PWM inverter controlled by position feedback scheme. In order to provide the desired thrust force with specific value and direction, a position feedback is required to control the free piston engine motion through controlling the inverter switches using PWM control scheme.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.158-163
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• 2001

The effect of phosphate on the production of avermectin B1a was studied. Response surface methodology was applied to optimize the concentration of organic nitrogen sources. The portion of B1b in total avermectins was decreased from 5.8% to 3.0% by the addition of 1.5 g/ι inorganic phosphate to the production medium. Among organic nitrogen sources, soybean meal was the most effective on avermectin biosynthesis. Results showed that B1a productivity was increased by 44.8% in a laboratory scale fermenter cultivation of Streptomyces avermitilis YA99-40 through fed-batch process. A maximal B1a productivity was obtained by repeated 30 and 20 g/ι of glucose feeding at 136 and 206 hour, respectively. The B1a productivity was increased by 86.3% and the proportion of B1a in the total avermectins was improved from 38% to 45% with respect to the control process. These results would be very useful for enhancing productivity of B1a in an up-scaled processes.