• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.101-106
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• 1996

In this study, filling performance of concrete is investigated experimentally for the developmenmt of the concrete to be used in concrete filled steel tubular columns with inner diaphrams. Water-cement ratio with 3 levels, unit water contents with 5 levels, unit coarse aggregate contents with 5 levels, and slump flow with 3 levels are selected for test variables. For the estimation of the filling properties of the concrete, slump flow, V-type funnel time, U-type box height are measured and compared. A device which simulates the steel tubular column is designed and three kinds of concrete are tested with it. As the results, the filling performance is decreased with increasing coarse aggregate content. And, within the scope of this study, concretes with coarse aggregate content less than 880 kg/$\textrm{m}^3$ show good filling performance. To prevent excessive settlement of the concrete pumped into the steel tubular column, slump flow should be controlled within the limited range.

• 소성∙가공
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• 제8권2호
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• pp.188-199
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• 1999

Semi-Solid Forming Process(Thixoforming, Rheocasting) is a novel forming process which has some advantages compared with conventional die casting, squeeze casting and hot/cold forging. In this study. Thixoforming process was selected as analysis processing in terms of billet handling and easiness of automation process. The Thixoforming process consists of reheating process of billet, billet handling, filling inot the die cavity and solidification of SSM part. In filling process, two rheology models which were Newtonian and Non-Nettonian model (Ostwald-deWaele)were verified with experimental results. The Ostwald-deWaele model shows the good agreement to the real flow and filling phenomena in die cavity. To give a boost the economical efficiency of Thixoforming process and to ensure the good forming result, reheating device coupled die set was proposed and the initial billet temperature for system that was found from experimental resluts. This study presents an overview of application of numerical analysis for simulation of semi-solid metal forming process to reduce the lead time for development of manufacturing part in industrial field.

• Current Applied Physics
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• 제18권11호
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• pp.1451-1457
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• 2018

Injection compression molding (ICM) is an advantageous processing method for producing thin and large polymeric parts in a robust manner. In the current study, we employed the ICM process for an energy-related application, i.e., thin and large polymeric battery case. A mold for manufacturing the battery case was fabricated using injection molding. The filling behavior of molten polymer in the mold cavity was investigated experimentally. To provide an in-depth understanding of the ICM process, ICM and normal injection molding processes were compared numerically. It was found that the ICM had a relatively low filling pressure, which resulted in reduced shrinkage and warpage of the final products. Effect of the parting line gap on the ICM characteristics, such as filling pressure, clamping force, filling time, volumetric shrinkage, and warpage, was analyzed via numerical simulation. The smaller gap in the ICM parting line led to the better dimensional stability in the finished product. The ICM sample using a 0.1 mm gap showed a 76% reduction in the dimensional deflection compared with the normal injection molded part.

• Advances in concrete construction
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• 제16권5호
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• pp.231-241
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• 2023

The purpose of this study was to evaluate the practical application of high-flowing concrete for a steel-concrete panel (SCP) module for a liquefied natural gas (LNG) storage tank. We evaluated the physical properties and filling performance of the developed concrete for the SCP module. First, slump tests were performed to evaluate the performance of the proposed standards for the filling tests. All the concrete mixes showed satisfactory performance. Based on the results of the previous study, the reliability of the required time measured using the T₅₀₀ test and the rheometer results measured before and after pumping was 0.94, indicating that segregation and blocking should not occur. L-box and U-box tests were conducted before and after pumping. All the recommended standards showed satisfactory performance. The SCP structural module for LNG storage tanks was fabricated to a full scale to evaluate its practical application at the final site. Satisfactory filling performance was confirmed for all the specimens.

• 대한소아치과학회지
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• 제43권2호
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• pp.129-136
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• 2016

본 연구의 목적은 근관 충전재로서 MTA(Endoseal, Endoseal MTA)의 밀폐 효과와 효율을 평가하는 것이다. 총 106개의 발거된 단근치가 사용되었으며, 충전된 실러에 따라 AH군(AH-26), PR군(ProRoot MTA), ES군(Endoseal), EM군(Endoseal MTA)으로 나누어졌고, 모든 충전시 소요 시간이 측정되었다. 그 군들은 다시 A 하위군, B 하위군으로 나누어 근관벽과의 밀폐성과 상아세관내 실러의 침투도를 각각 평가하였다. 결과는 근관 충전용 MTA는 AH-26에 비해 근관벽과의 밀폐성과 상아세관 침투도는 떨어졌으며, ProRoot MTA와 비교시 근관벽과의 밀폐성은 차이가 없었지만, 상아세관 침투도는 높았다. 작업 시간은 근관 충전용 MTA가 ProRoot MTA와 AH-26에 비해 짧았다. 결론적으로 근관 충전용 MTA는 레진계 실러보다 근관 밀폐 효과는 떨어지지만 MTA가 필요한 근관 충전시 효과적인 대안이 될 수 있다.

• 소성∙가공
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• 제14권3호
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• pp.269-276
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• 2005

The purpose of this research is the warpage reduction for intake-manifold which is made to the injection molding. Intake-manifold is assembling to ultra sonic welding after forming. Therefore deformation is influence on the performance and manufacture to intake-manifold product. Location and number of gates, filling time, mold temperature, packing time, packing pressure and cooling time are factors that affect the deformation of injection molding product. Therefore, the injection molding characteristics of intake-manifold and the estimated deformation are detected by CAE analysis and compare measuring data in this study.

• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.309-313
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• 2014

The volume fraction of the coarse aggregate in the conventional plastic concrete is controlled relatively low to ensure a required workability. In this paper, a new type of coarse aggregate interlocking concrete with strength ranging from C30 to C80 was prepared with scattering-filling aggregate process. The strength of concrete prepared with this method increases obviously whereas the shrinkage decreases significantly, the cement dosage in the concrete decreased 20 % at the same time. The microhardness of the ITZ between the cement paste and scattering-filling aggregate is higher than that of the original aggregate, the ITZ become narrower and tighter also. The interlocking and more even distribution of the coarse aggregate and the water absorption of the addition of extra amount of coarse aggregates contribute to the strength and performance improvement of the concrete prepared with scattering-filling aggregate process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.370-370
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• 2012

Feature size of Cu interconnects keep shrinking into several tens of nanometer level. For this reason, the Cu interconnects face challenging issues such as increase of electro-migration, line-width dependent electrical resistivity increase, and gap-filling difficulty in high aspect ratio structures. As the thickness of the Cu film decreases below 30 nm, the electrical resistivity is not any more constant, but rather exponential. Research on alloying with other elements have been started to inhibit such escalation in the electrical resistivity. A faint trace of Al added in Cu film by sputtering was reported to contribute to suppression of the increase of the electrical resistivity. From an industrial point of view, we introduced cyclic metal organic chemical vapor deposition (MOCVD) in order to control Al concentration in the Cu film more easily by controlling the delivery time ratio of Cu and Al precursors. The amount of alloying element could be lowered at level of below 1 at%. Process of the alloy formation was applied into gap-filling to evaluate the performance of the gap-filling. Voidless gap-filling even into high aspect ratio trenches was achieved. In-depth analysis will be discussed in detail.

• 한국안전학회지
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• 제33권6호
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• pp.50-57
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• 2018

The purpose of this study is to evaluate the practical application of the self consolidating concrete for the steel concrete pannel (SCP) in module LNG storage tank proposed in the previous research. We evaluated the physical properties and filling performance of developed concrete for the SCP module. First, a slump flow test was conducted to evaluate the performance of the proposed guidelines for the filling test. As a result, all of the concrete used showed satisfactory performance. Based on the results of the previous study, it was found that the reliability of the required time measured by the $T_{500}$ test and the rheometer results measured before and after pumping was 0.94 which means the separation and blocking should not occur. The L-box test and the U-box test were conducted before and after pumping. All of the guidelines suggested showed satisfactory performance. SCP module for LNG storage tanks was fabricated on actual size scale to evaluate the practical application at the final site. As a result, it was confirmed that satisfactory filling performance was obtained in all the specimens.

• 대한설비공학회지:설비저널
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• 제16권4호
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• pp.406-414
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• 1987

As one of the explosion suppression methods of LPG tank exposed to hot environment by an accident or fire, some material which has large heat capacity and thermal conductivity can be installed inside the LPG tank in order to suppress the temperature increasement of tank wall. In the present study, theoretical model for the horizontally locating cylindrical LPG tank with and without the aluminum explosion suppression material has been developed to predict the characteristics of system. As a parametric study, effects of two major parameters, thickness of material filling and initial vapor volume fraction, on the time variation of wall temperature, temperature and pressure in tank are numerically examined. The results of present study show that the thickness of material filling does not give big differences in the suppression characteristics when the thickness of filling is larger than three inches. In case of material filling, there are marked suppression effects to the increase-ment of wall temperature, average vapor temperature and pressure in tank compared with the case of no filling.