• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.103-110
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• 2020

Riveting is mainly used to assemble the aircraft fuselage. An average of 2~3 workers is needed to assemble an aircraft fuselage consisting of various size frames by riveting. In this study, a riveting process that enables one-person operation using an automated C-frame riveting machine was proposed for improving the efficiency of productivity. The proposed process was verified stability through structural analysis. In the range that can maintain structural stability, panel thickness of the riveting machine and shape were modified to optimizing the shape for reducing the weight of the riveting process. The structural analysis was performed by software ANSYS workbench 19.2. The optimized riveting machine was reduced by 257kg compared to the existing model.

• Journal of Welding and Joining
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• v.21 no.6
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• pp.26-32
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• 2003

Arc welding process has indicated that it suffers from many flaws. It's because requirement of products is diverse and factors which affects the quality is also various. Therefore, in order to stabilize the welding process, it is important to choose a proper welding machine for the each process, and to evaluate the welding process capability of each machine. In this study, rational and simple index to evaluate the welding machine was set the coefficient of resistance variation through the arc stability examination such as spatter generation weight and bead configuration uniformity etc. And the method to evaluate the process capability index was developed by application of 6$\sigma$.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.452-457
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• 2000

The object of this study is to develop a reliable FEM simulation technique for the analysis of can making process using PAM-STAMP software. The processes consist of doming and necking in addition to drawing, redrawing. After body making process, this study analyzed the stability for internal pressure by simulating buckling test. Through these technique, we estimated the dome reversal pressure of steel D&I Can for various can profile and process conditions. From this study, we found the cause and mechanism of wrinkling during necking process. This mechanism is largely affected by can wall thickness and the clearance between knock out punch and necking die. The dome reversal pressure improves with increasing dome depth. These results validate the usefulness of the developed simulation technique for the analysis of body making process and optimization of the dome profile.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.67-73
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• 2014

The oil in mackerel muscle was extracted using an environment friendly solvent, supercritical carbon dioxide (SC-$CO_2$) at a semibatch flow extraction process and an n-hexane. The SC-$CO_2$ was maintained at a temperature of $45^{\circ}C$ under pressures ranging from 15 to 25 MPa. The flow rate of $CO_2$ (27 g/min) was constant during the entire 2 h extraction period. The fatty acid composition of the oil was analyzed using gas chromatography (GC). Significant concentrations of eicosapentaenoic acid (EPA) acid and docosahexaenoic acid (DHA) acid were present in the SC-$CO_2$ extracted oil. The oil extracted using SC-$CO_2$ exhibited increased stability compared with n-haxane extracted oil. Particles of mackerel oil together with the biodegradable polymer, polyethylene glycol (PEG) were formed using a gas saturated solution process (PGSS) with SC-$CO_2$ in a thermostatted stirred vessel. Different temperatures ($45-55^{\circ}C$), pressures (15-25 MPa) and a nozzle size $400{\mu}m$ were used for PGSS with a 1 h reaction time. The stability of mackerel oil in the particles did not changed significantly.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.32-40
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• 2019

During the manufacturing process of a printed circuit board(PCB), fumes and mists are generated as the ink dries on the PCB surface. The generated fumes and mists are deposited in the dryer wall and the exhaust duct. Deposited fumes and mists may present a fire hazard if the dryer temperature control system fails. In this study, the thermal stability of the fumes and mists deposited in the dryer and ducts has been analyzed by experimental methods such as thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), auto ignition temperature (AIT), and multiple mode calorimetry(MMC). According to the experimental analyses, experimental samples are likely to generate gas at the temperature ($180{\sim}240^{\circ}C$) that deviates from the normal operating temperature ($150{\sim}156^{\circ}C$). It has been shown that the thermal stability is degraded when the temperature is deviated from the normal operating temperature. In the end, engineering and management safety measures of accidental prevention have been suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.469-470
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• 2010

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.177-184
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• 1999

In general tile evaluation process of rock slope stability is an ambiguous system which is made up of ideas subjected to practical experience of an expert. This paper aims to propose more effective methods that helps engineers to evaluate the stability of rock slope by using RMR(Rock Mass Rating for the Geomechanics Classification) and Stereo-graphic Projection and Fuzzy Approximate Reasoning Concept. the result of this paper is that a rational evaluation of rock slope stability and countermeasures can be achieved thorough RMR. and Stereo-graphic Projection and Fuzzy Approximate Reasoning Concept.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.210-217
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• 2009

This paper presents the analytical prediction of stability lobes in milling. The stability lobes are obtained by measuring the frequency response function (FRF) of a machining center at the cutting point of the end mill cutter, identifying cutting constants, and approximating cutting force coefficients. The stability lobes are experimentally verified through cutting tests.

• YAKHAK HOEJI
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• v.25 no.1
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• pp.37-42
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• 1981

Penicillin derivatives have a stability problem by hydrolysis of their .betha.-lactam ring. At high temperature, crystal water is released from penicillin derivatives, especially ampicillin trihydrate and concerns itself in hydrolysis. Penicillin derivatives having crystal water show different crystal states and different stability according to the variation of different condition on the process of manufacturing. The stability of ampicillin trihydrate in solid states was determined. Physico-pharmaceutical properties of this compound were determined by using IR spectra, X-ray powder diffraction and differential thermal analysis (DTA).

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.2
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• pp.43-49
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• 2000

It is a complex process to analyze power system voltage stability problems with all of the dynamics of a system, because a large power network system sophisticatedly consists of generators, lines, loads and so forth. So we considered the dynamics of loads so as to analyze voltage stability method- by carrying out an analysis of steady state voltage stability and dynamic voltage stability simultaneously. To perform a steady state voltage stability program in advance makes it possible to cut down on laborious calculations so that an analysis of dynamic voltage stability becomes concise. The validity and efficiency of the method presented in this paper were verified by applying the IEEE 14 bus system.