• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.180-181
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• 2019

South Korea has long been without major earthquakes. But 317 public facilities have been damaged by Po-Hang earthquake. Among them, 103 educational facilities suffered 25.6 billion won worth of damage. This is the most damaging of public facilities. The earthquake damage was mainly centered on non-seismic retrofit educational facilities and masonry architectural wall systems installed on the outer walls of buildings. Therefore, the purpose of this study is to develop a filling material that can be applied to the non-seismic retrofit of masonry architectural wall systems installed on the outer walls of educational facilities. To achieve the objective, first, set the filling material requirements. Second, set the sequence model of experiments and prepare for the experiment. Third, after the experiment, analyze the results obtained through the experiment. Forth, the optimal filling material is selected by comparing the analyzed results with the requirements. As a results, E-S-X sample using epoxy resin were selected for the seismic retrofit of masonry architectural wall systems in educational facilities. In the future, this study can be used as a basic material for developing seismic reinforcement methods guidelines in domestic existing educational facilities.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.4
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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.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4005-4012
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• 2022

As high-level radioactive waste (HLW) generated from nuclear power plants is harmful to the human body, it must be safely disposed of by an engineered barrier system consisting of disposal canisters and buffer and backfill materials. A gap exists between the canister and buffer material in a HLW repository and between the buffer material and natural rock-this gap may reduce the water-blocking ability and heat transfer efficiency of the engineered barrier materials. Herein, the basic characteristics and thermal properties of granular bentonite, a candidate gap-filling material, were investigated, and their effects on the temperature change of the buffer material were analyzed numerically. Heat transfer by air conduction and convection in the gap were considered simultaneously. Moreover, by applying the Korean reference disposal system, changes in the properties of the buffer material were derived, and the basic design of the engineered barrier system was presented according to the gap filling material (GFM). The findings showed that a GFM with high initial thermal conductivity must be filled in the space between the buffer material and rock. Moreover, the target dry density of the buffer material varied according to the initial wet density, specific gravity, and water content values of the GFM.

• Tunnel and Underground Space
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• v.17 no.3 s.68
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• pp.175-185
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• 2007

When filling material such as clay is included along the discontinuity, it may cause instability on a slope even if the direction of discontinuity works in a positive way. In the study area, slope sliding occurred at the boundary between a clay filling material and weathered soil because the physical properties differ across the boundary; and this is very similar to the situation where foliation in a rock works as a weak zone during a structural behavior, causing an inter-layer slip. In most analysis, if there exists a clay filling material, a single discontinuity is assumed to perform analysis. In those cases, the discontinuity is modeled as a slip surface within clay. Therefore, the characteristics of the boundary are not considered in the analysis, so that ultimately the physical property of clay usually prevails. The result of evaluating the slope stability affected by clay filling material shows the significant difference in the safety level due to the strength parameter depending on the failure type of the discontinuity by a filling material.

• Restorative Dentistry and Endodontics
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• v.44 no.2
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• pp.18.1-18.9
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• 2019

Objective: This study evaluated the presence of residual root canal filling material after retreatment using micro-computed tomography (micro-CT). Materials and Methods: Extracted human teeth (single- and double-rooted, n = 21/each; C-shaped, n = 15) were prepared with ProFile and randomly assigned to three subgroups for obturation with gutta-percha and three different sealers (EndoSeal MTA, EndoSequence BC sealer, and AH Plus). After 10 days, the filling material was removed and the root canals were instrumented one size up from the previous master apical file size. The teeth were scanned using micro-CT before and after retreatment. The percentage of remaining filling material after retreatment was calculated at the coronal, middle, and apical thirds. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni post hoc correction. Results: The tested sealers showed no significant differences in the percentage of remaining filling material in single- and double-rooted teeth, although EndoSeal MTA showed the highest value in C-shaped roots (p < 0.05). The percentage of remaining filling material of AH Plus and EndoSeal MTA was significantly higher in C-shaped roots than in single- or double-roots (p < 0.05), while that of BC sealer was similar across all root types. EndoSeal MTA showed the highest values at the apical thirds of single- and double-roots (p < 0.05); otherwise, no significant differences were observed among the coronal, middle, and apical thirds. Conclusions: Within the limitations of this study, a large amount of EndoSeal MTA remained after retreatment, especially in C-shaped root canals.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.13.1-13.13
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• 2022

Objectives: This study evaluated the efficacy of 3 reciprocating systems and the effects of 2 instruments for irrigant activation on filling material removal. Materials and Methods: Forty mesiobuccal roots of maxillary molars were prepared up to size 25.06 and obturated. Micro-computed tomography (micro-CT) examination #1 was performed. Teeth were then divided into 4 groups (n = 10), according to the retreatment protocol: (1) manual, (2) Reciproc Blue, (3) WaveOne Gold, and (4) X1 Blue. Micro-CT examinations #2 and #3 were performed after filling removal and repreparation, respectively. Next, all teeth were divided into 2 new groups (n = 20) according to the irrigant activation protocol: XP Clean (XP Clean size 25.02) and Flatsonic (Flatsonic ultrasonic tip). Micro-CT examination #4 was performed after irrigant activation. Statistical analysis was performed with a significance level set at 5%. Results: WaveOne Gold removed a significantly greater amount of filling material than the manual group (p < 0.05). The time to reach the WL was similar for all reciprocating systems (p > 0.05). X1 Blue was faster than the manual group (p < 0.05). Only manual group improved the filling material removal after the repreparation stage (p < 0.05). Both activation protocols significantly improved the filling material removal (p < 0.05), without differences between them (p > 0.05). Conclusions: None of the tested instruments completely removed the filling material. X1 Blue size 25.06 reached the working length in the shortest time. XP Clean and Flatsonic improved the filling material removal.

• The Journal of the Korean dental association
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• v.55 no.5
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• pp.339-350
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• 2017

The aim of the study was to analyze the distribution of dental filling materials for carious permanent teeth of school children in a city. The study was designed as time-serial study, using the data of the dental survey for children aged 8-, 10- and 12-year children living in Gimhae city. The samples were selected by stratified clusters sampling. The number of surveyed samples in depth-analysis for types of dental filling materials were 567 in 2009 and 331 in 2013, respectively. They had dental restorations on one or more teeth. The changing pattern of used dental filling materials was analyzed between 2009 and 2013. Statistical analysis was conducted according to variables related to dental filling material type; DMFT and DMFS index, number of fissure sealed teeth and surface and surveyed year. Amalgam filling rate decreased from 27.9% in 2009 to 18.8% in 2013, while filling rate of tooth-colored materials increased from 56.1% in 2009 and 68.9% in 2013. Amalgam filling rate was a negative correlation with filling rate of tooth-colored materials or gold and number of fissure sealed teeth and a positive correlation with DMFT index. Filling rate of tooth-colored materials was a negative correlation with filling rate of amalgam or gold and DMFT index and a positive correlation with number of fissure sealed teeth. The light-curing composite resin should be included in the reimbursement range of National Health Insurance to solve an inequity of dental health care services.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.591-594
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• 2003

In the present study, we developed a filling material composed of poly(lactic-co-glycolic) acid (PLGA) microspheres with applications in the treatment of facial wrinkle and urinary incontinence and studied the feasibility of injecting the filling materials in animal models for plastic surgical and urological applications. Former filling materials including Teflon, Silicon, and collagen have shown a few shortcomings such as inflammation reaction, particles migration or volume decrease. We injected PLGA microspheres into the subcutaneous dorsum of mice. Injected volume was constantly maintained after implanting. We hardly found either inflammation reaction or migration. This material overcomes the problems of the current filling materials and could be utilized as a new filling material for plastic surgical and urological applications.

• International Journal of Concrete Structures and Materials
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• v.8 no.4
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.8-10
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• 2013

Inorganic binding material was made by recycled resource and its applicability as pile-filling material was examined. The result was that the material had same liquidity with the liquidity of OPC and high reactivity with site soil. According to dynamic/static loading tests by site test-construction, the inorganic binding material met both design bearing capacity and settlement. Since the inorganic binding material showed same or better performance than OPC, the utilization possibility of the inorganic binding material made of recycled resource as pile-filling material was verified.