• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.45-53
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• 2015

The fact that gas hydrate and/or paraffin wax is frequently plugged in offshore pipeline has been become very significant for offshore piepline flow assurance. An active electrical heating along pipeline has adapted in resolving flow assurance problem like as gas hydrate and wax plugging. This study represents a novel internal-swirled heater which was designed and fabricated for more effective heating and thermal mixing through pipeline. The internal-swirled heater suggested in this study shows higher thermal mixing performances than the conventional external-traced heater.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.1
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• pp.1-6
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• 2014

Styrene-butadiene-styrene copolymer(SBS)/Clay nanocomposites were prepared by melt mixing method with organic clay modified with dimethyl dihydrogenated-tallow amine(Cloisite 15A) and methyl tallow bis (2-hydroxy-ethyl) amine(Cloisite 30A), respectively. From the results of XRD, we found that mono layered silicates were dispersed in SBS matrix and they were exfoliated nanocomposites. Mechanical properties of exfoliated SBS nanocomposites were more improvedl than those of SBS. Especially, it was found that the addition of small amount of organoclay was enough to improve mechanical properties without increasing hardness.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.535-548
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• 2015

A series of experimental results on thin mild steel plates clamped at the boundary subjected to gas detonation shock loading are presented. Detonation occurred by mixing Acetylene (C2H2)-Oxygen (O2) in various volume ratio and different initial pressure. The applied impulse is varied to give deformation in the range from 6 mm to 35 mm. Analytical modeling using energy method was also performed. Dependent material properties, as well as strain rate sensitivity, are included in the theoretical modeling. Prediction values for midpoint deflections are compared with experimental data. The analytical predictions have good agreement with experimental values. Moreover, it has been shown that the obtained model has much less error compared with those previously proposed in the literature.

• Carbon letters
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• v.10 no.4
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• pp.320-324
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• 2009

We investigated the effect of diameter and content of carbon nanotubes (CNTs) on the physical properties of styrenebutadiene rubber (SBR)/CNTs nanocomposites. CNTs-reinforced SBR nanocomposites were prepared by the melt mixing process. CNTs with different diameters were synthesized by the chemical vapor deposition method (CVD). In this work, the mechanical property and other physical properties of SBR/CNTS nanocomposites were discussed as a function of the content and diameter of CNTs.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1343-1344
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• 2007

In this paper, we investigated mechanical characteristics about thermal properties in semiconductor layer of power cables. Method of specimen making used solution mixing and Tensometer 2000 of Alpha used for measurement of stress and strain. Semiconductor layer made an experiment on separately environmental temperature$[25^{\circ}C]$ and high temperature$[90^{\circ}C]$ which running temperature$[90^{\circ}C]$ of cables exposed. As a result, specimen of applicable DFS(Dual Filler System) could know mechanical superiority that its structural characteristics reinforcement considered thermal characteristics.

• Korean Journal of Materials Research
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• v.31 no.6
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• pp.339-344
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• 2021

Composite materials offer distinct and unique properties that are not naturally inherited in the individual materials that make them. One of the most attractive composites to manufacture is the aluminum alloy matrix composite, because it usually combines easiness of availability, light weight, strength, and other favorable properties. In the current work, Powder Metallurgy Method (PMM) is used to prepare Al2024 matrix composites reinforced with different mixing ratios of yttrium oxide (Y₂O₃) particles. The tests performed on the composites include physical, mechanical, and tribological, as well as microstructure analysis via optical microscope. The results show that the experimental density slightly decreases while the porosity increases when the reinforcement ratio increases within the selected range of 0 ~ 20 wt%. Besides this, the yield strength, tensile strength, and Vickers hardness increase up to a 10 wt% Y₂O₃ ratio, after which they decline. Moreover, the wear results show that the composite follows the same paradigm for strength and hardness. It is concluded that this composite is ideal for application when higher strength is required from aluminum composites, as well as lighter weight up to certain values of Y₂O₃ ratio.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3538-3548
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• 1996

In this study, as a part of basic study for developing the simulation program for the assemssment of reliability of electronic EMC packaging which covers from EMC mixing step to thermal analysis, comparison between a measured and predicted values of material properties of EMC and finitde element analysis of thermal stress are performed. For the experimental testing specimens of fifty, sixty hive and eighty percent filler($13\mu m$, spherical silica) weight fraction are fabricated using tranfer molding. Coefficient of thermal expansion, elastic modulus and thermla conductivity are measured using these specimens and then these measured values are compared with the predicted values by various equations ( such as dilute suspension method. self consistent method, generalized self consistent method, Hashin-Shtrikman's bounds. Shapery's bounds, Nielsen's method and others). Measured values are distributed within the upper and lower bounds of equations. Measured elastic modulus and coefficient of thermal expansion approaches closely the perdicted values with self consisten mehtod and upper bound of Shaperys equation respectively. However small differences of thermal conductivity between the different filler volume fraction are obserbed. FEM analysis indicates that firstly stress is concentrated at the corner section of EMC and secondly EMC with eighty percent filler weight fraction shows less thermal stress when package is cooling down and relatively high thermal stress when package is heating up.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.59-64
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• 2004

In this paper, the error compensation method of the low-cost IMU is proposed. In general, the position and attitude error calculated by accelerometers and gyros grows with time. Therefore the additional information is required to compensate the drift. The attitude angles can be bound accelerometer mixing algorithm and the heading angle can be aided by single antenna GPS velocity. The Kalman filter is used for error compensation. The result is verified by comparing with the attitude calculated by Attitude Heading Reference System with Micro Electro Mechanical System for a basis

• Textile Coloration and Finishing
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• v.28 no.2
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• pp.101-108
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• 2016

Polypropylene(PP)/multiwalled carbon nanotubes(MWCNT) nanocomposites films and PP/poly(vinyl alcohol)/CNT nanocomposites films were prepared through melt mixing method by the extruder. The PP/CNT nanocomposites films, which contain CNT of a variable content, were prepared for the first time and research on a appropriate content of the CNT on the PP/CNT nanocomposites films was conducted. The effects of take-up speed of the extruder on the mechanical and chemical properties of the PP/CNT and PP/PVA/CNT nanocomposites film were studied. Field emission scanning electron microscope(FE-SEM) was used to examine the surface morphology and the DSC measurement and tensile test were conducted. It was found that the properties decreased when take-up speed was increased.

• Journal of Soil and Groundwater Environment
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• v.25 no.3
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• pp.23-31
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• 2020

The performance of a downward-irradiation sonoreactor was investigated using calorimetry, KI dosimetry, luminol (Sonochemiluminescence, SCL) method, and aluminium foil erosion method as one of the basic steps for the optimal design of downward-irradiation sonoreactors. The applied frequency was 28 kHz and the input electrical power was 280 - 300 W. The liquid height, from the reactor bottom to the transducer module surface, ranged from 1λ (53.6 mm) to 2λ (107.1 mm). For various liquid heights, the magnitude of calorimetric power and the mass of cavitation-generated I₃^- ion varied significantly. It was found that the additional application of mechanical mixing resulted in higher sonochemical activity, especially in the cavitational active zone, which was induced by violent liquid flow in the reactor. In aluminium foil erosion tests, it was found that less ultrasound energy reached the bottom of the reactor due to the violent liquid flow and no significant sonophysical effect was observed for higher mixing rate conditions (100 and 200 rpm).