• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.133-142
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• 2014

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF Slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. In this study, We've got the plan to assure the chemical stability of EAF Slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF Slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF Slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.127-133
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• 2020

It is important to measure the quantitative adhesive strength between an organic adhesive and a metal adherend. In measuring the adhesive strength between an organic adhesive and a metal adherend, the effect of the kind and thickness of the adherend on the adhesive strength was studied. Two kinds of metal adherends were selected, aluminum (Al1050) and stainless steel (STS304), and a dolly test and a lap shear test were used to measure the adhesive strength. When measuring the adhesive strength between the organic adhesive and the metal adherend by the tensile stress mode of dolly test, the change in the thickness of the metal adherend had little effect on the adhesive strength, however, the adhesive strength was different depending on the kind of the adherend. On the other hand, when measuring the adhesive strength between the organic adhesive and the metal adherend by the lap shear test, the change in the relative thickness of the metal adherend had an effect on the adhesive strength. The reason is that the bending phenomenon of the adherend occurring in the edge of bonding region during the lap shear test contributes to lowering the adhesive strength by generating additional tensile stress in the bonding region. From this work, it is concluded that the dolly test could be widely used when measuring the quantitative adhesive strength of organic adhesives and metal adherend because there is little change in adhesive strength even though the thickness of the adherend is changed.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.863-870
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• 2016

We investigated the physical/chemical phenomena that a slow loss of $CO_2$ inventory into sodium after the sodium-$CO_2$ boundary failure in printed circuit heat exchangers (PCHEs), which is considered for the supercritical $CO_2$ Brayton cycle power conversion system of a sodium-cooled fast reactor (SFR). The first phenomenon is plugging inside narrow sodium channels by micro cracks and the other one is damage propagation referred to as wastage combined with the corrosion/erosion effect. Experimental results of plugging shows that sodium flow immediately stopped as $CO_2$ was injected through the nozzle at $300{\sim}400^{\circ}C$ in 3 mmID sodium channels, whereas sodium flow stopped about 60 min after $CO_2$ injection in 5 mmID sodium channels. These results imply that if pressure boundary of sodium-$CO_2$ fails a narrow sodium channel would be plugged by reaction products in a short time whereas a relatively wider sodium channel would be plugged with higher concentration of reaction products. Wastage by the erosion effect of $CO_2$ (200~250 bar) hardly occurred regardless of the kinds of materials (stainless steel 316, Inconel 600, and 9Cr-1Mo steel), temperature ($400{\sim}500^{\circ}C$), or the diameter of the $CO_2$ nozzle (0.2~0.8 mm). Velocities at the $CO_2$ nozzle were specified as Mach 0.4~0.7. Our experimental results are expected to be used for determining the design parameters of PCHEs for their safeties.