• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.637-645
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• 2008

It is very hard to control the quality of coating work in shipbuilding process, because it is highly affected by several parameters such as space between object and nozzle tip, spray velocity, pressure, tip size, etc.. Even so a coating work in shipbuilding is done by workers' experience and skill as yet. It causes not only an excessive use of paints but also a decrease of productivity. In order to solve this problem, we developed a formula that predicts the film thickness and determined the proper coating pattern. Also we had done a series of experiments to verify the results of this study.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.61-66
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• 2011

The purpose of this paper is to design a hydraulic actuator to operate under high pressure conditions. The flow characteristics under design conditions of hydraulic actuator were numerically conducted by commercial fluid dynamic code(ANSYS CFX V11). The numerical analysis was performed by transient technique according to the variation of stroke times, which was changed from 0 to 1 second by interval of 0.01. Turbulence model, $k-\omega$ SST was selected to secure more accurate prediction of hydraulic oil flow. The ICEM-CFD 11 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate which was supplied to the hydraulic actuator was 30.4l/min. These results are in good agreement with design results within 3.5% error.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.47-53
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• 2011

From recent research, it has revealed that Electroacitve polymer(EAP) has a physical limitation. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. In this paper, we suggest the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. Using mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we disperse Single-walled carbon nanotubes(SWCNT). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. In the result, we fabricated a disperse SWCNT/Nafion composite uniformly.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.538-541
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• 1996

The flow of the molten drop in the GMAW was observed to explain the mechanism of its formation and break-up process. Fluid flew analysis was made with the assumption that the electrode wire acts like fluid, and it is shown how the convection of the drop inside affects its flow, from the formation to the break-up of the drop. In later part, the process of the spray mode development at high current is shown, as well as the one of the globular mode, by the fluid flow analysis.

• Journal of Information Display
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• v.6 no.4
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• pp.40-44
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• 2005

Nanometer-sized bismuth oxide with a diameter of about 80 nm was used as a new electron reflection material in a 29" Real Flat CPT. This bismuth oxide was well dispersed over pH8 in slurry. Spray coating was performed clearly and uniformly and was ensured that there was no clogging of shadow mask hole. Coating thickness was expressed to the brightness of chromaticity for the sprayed layer and was also well controlled during the spraying process. Doming was improved by about 10% in spite of the similar coating weight in comparison with the average 3.5 ${\mu}m$ of the conventional bismuth oxide.

• Analytical Science and Technology
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• v.19 no.6
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• pp.519-528
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• 2006

An analytical method for the determination of thyroid hormones in urine samples has been studied by using solid-phase extraction and high-performance liquid chromatography/diode array detector/electro-spray mass spectrometry. Seven thyroid hormones were successfully separated by gradient elution on the reverse phase Hypersil ODS column (4.6 mm I.D., 100 mm length, particle size $5{\mu}m$) with ammonium formate buffer and acetonitrile, and UV spectra and mass fragment could be confirmed. The extraction recoveries of thyroid hormones in the urine samples (pH 3) were in the range of 89.0-113.1% with solid-phase extraction by C18, followed by elution with 4 ml of methanol/ammonium hydroxide (9 : 1). The calibration curves showed good linearity with the correlation coefficients ($r^2$) varying from 0.992 to 0.998 and the detection limits of all analytes were obtained in the range of 2-4 ng/ml (3.8-13.0 pmol/ml).

• Resources Recycling
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• v.17 no.6
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• pp.79-88
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• 2008

This study is the previous stage for the mass production technology development of the nano-sized tin oxide powder by the recycling of the wasted tin metal, and nano-sized tin oxide powder with the average particle size below 50 nm is prepared from the tin chloride solution by the spray pyrolysis process. As the reaction temperature increases from 800 to 850, the average particle size of the generated powder increases from 20 to 30 nm. As the reaction temperature increases to 900, the droplet type is composed of the particles with the average size of the 30 nm. while the average size of the independent particles increases up to $80{\sim}100$ nm and the surface microstructure becomes more solid. Until $900^{\circ}C$, as the reaction temperature increases, the XRD peak intensity increases, while the specific surface area decreases. When the reaction temperature increases to 950, most of the powder appears with the independent type and the average particle size decrease down to 70 nm. The XRD peak intensity greatly decreases and the specific surface area increases almost twice.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.335-342
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• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• Clean Technology
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• v.8 no.2
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• pp.101-110
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• 2002

Concurrent development system which includes design, analysis, basic experiment and performance test procedure for rotary atomizing painting equipment was established. Basic design specifications of the equipment parts were determined according to the overall design requirements of painting equipment using conceptual design model. On the basis of derived design specifications, design and analysis procedures was proposed for developing each equipment part. Also proposed are experiment and test methods to investigate the spray and transfer characteristics of designed painting equipment, and their measurement variable, process and evaluation criteria are constructed. The present development system was validated by applying its entire processes to the actual painting equipment.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1891-1896
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• 2004

The present article proposes a new droplet collision model including the stretching separation regime and the formation of satellite droplets. The new model consists of a several equations to calculate the post-collision characteristics of colliding droplets and satellite droplets. These equations are derived from the energy balance of droplets between before and after collision. For binary collision of water droplets, the new model shows good agreement with experimental data for the number of satellite droplets. Nevertheless, it is thought that, in order to guarantee the generality of the new model, the improvements should be performed to consider the effects of the bouncing and the reflexive separation, which is essential process in the collision of hydrocarbon droplets.