• Korean Journal of Heritage: History & Science
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• v.45 no.2
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• pp.100-113
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• 2012

The tombstone of Yi Chungmugong in the Joseon Dynasty located Namhae, Gyeongnam is consisted of sandstone. The Bisin and Bijwa of the tombstone have narrow range of magnetic value less than $0.2({\times}10^{-3}SI\;unit)$ and the Isu covered pigment on surface also has same magnetic susceptibility range. Therefore, the composition of all tombstone have similar lithological characteristics. The side of the tombstone appeared fine-grained sandstone to coarse-grained graywacke boundary clearly and back of tombstone observed lamination. Especially deterioration type is concentrated in front and back of the tombstone blistering (8.2% of back), scaling (10.2% of back), granular disintegration (28.1% of back) and discoloration (53.5% of front). Results of contaminants analysis, the front of the Bisin separated in 3 type of surface - granular disintegration-scaling. Among this area, surface detected Ca, S and Cl in high density, but these contaminants elements have more lower detect density from surface to granular disintegration. By contrast, on scaling area, these components are almost not detected, but Fe, K consisted of rock forming elements are detected. It is necessary to conservation and treatment of Yi Chungmugong tombstone in continuously, and salt cleaning on surface also needed. So through activity of conservation and restoration, epigraph preserved for their worth.

• Korean Journal of Heritage: History & Science
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• v.48 no.4
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• pp.62-73
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• 2015

The Tae-Jo Geonwolleung is the tomb of the first king Tae-Jo of the Joseon Dynasty in the complex of the Royal Tombs of the Joseon Dynasty which is listed in World Heritage, and it contains various types of stone properties. The material of the stone properties consist of a single type of medium-grained biotite granite, however, each properties have different intensity and types in deterioration phenomena according to their locations and purposes. The major deterioration types of the stones are analyzed as physical decomposition and biodeterioration. The exfoliation, breaking-out and granular decomposition are widespread types of the deterioration throughout the entire burial mound stone properties and surrounding stone properties. On the other hands, the colonization of mosses and plants, and contamination by foreign materials are found more frequent in the burial mound stone properties as these stones are in contact with the soil of the tomb mound and moisture in the soil helped biodeterioration. It is suggested that anti-biology treatment and physical reinforcement are applied to the deteriorated stones to prevent further damage on the stone components of the tomb.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1082-1087
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• 2021

The propeller shaft has different pattern of behaviors at each static, dynamic, and transient condition to a ship shaft system due to the effects of propeller weight and eccentric thrust, which increases the potential risk of bearing failure by causing local load variations. To prevent this, the various research of the shafting system has been conducted with the emphasis on optimizing the relative slope and oil film retention between propeller shaft and stern tube bearing at quasi-static condition, mainly with respect to the Rules for the Classification of Steel Ships. However, to guarantee a stability of the shafting system, it is necessary to consider the dynamic condition including the transient state due to the sudden change in the stern wakefield during rudder turn. In this context, this study cross-validated the ef ect of propeller shaft behavior on the stern tube bearing during port turn operation, which is a typical transient condition, by using the strain gauge method and displacement sensor for 50,000 DWT medium class tanker. And it was confirmed that the propeller eccentric thrust change showing relief the load of the stern tube bearing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.69-78
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• 2008

In this study, in order to verify the reinforcement effects of the cracked concrete tubes and culverts, static load test was conducted. After the load carrying capacity of the original concrete tubes (nominal diameter 0.8 m, 1.0 m, 1.5 m) and box culverts (inner width 2.0 m. 2.5 m) was reduced by the cracking test, the cracked concrete specimens were strengthened by installing profile with steel stiffener and high strength mortar. And then, the maximum load tests were conducted the renewal concrete tubes and box culverts. According to the method application, the load carrying capacity increased 1.66~3.50 times than it of the original tubes before applying the method. In case of the original box culverts, the load carrying capacity increased 1.66~3.10 times than the case before installing profile and high strength mortar. Also non-linear analysis was carried out by using the commercial FEM program of ABAQUS 6.6. Solid (C3D8R) elements and concrete damage plasticity option was applied to the analysis. For reflecting confined reinforcing bars in the analysis, the composite material properties were used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.881-893
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• 2008

The major objective of this study is to investigate the fatigue damage factor evaluation of immovability crossing for railway turnout by the field test and qualitative analysis. From the field test results of the servicing turnout crossing and qualitative analysis with frictional wear which section stiffness decreased, it was evaluated fatigue life of servicing turnout crossing. Most design practices have not taken advantage of the advanced theories in the modern fracture mechanics and finite element analysis due to complexity of analysis as well as the large quantity of vaguely defined parameters in actual designs. This paper considers fatigue problems in turnout crossing using effective analytical and design tools from the field of qualitative constraint reasoning. A set of software modules was developed for fatigue analysis and evaluation, which is easily applicable in engineering practices of designers. The techniques enable the use complex analysis formulations to tackle practical problems with uncertainties, and present the design outcome in two-dimensional design space solution. Appropriate engineering assumptions and judgments in carrying out these procedures, often the most difficult part for practicing engineers, can be partially produced by using qualitative reasoning to define the trends and ranges, interval constraint analysis to derive the controlling parameters, as well as design space to account for practical experience.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.82-82
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• 2020

염증 (Inflammation)은 물리적인 상처나 세균감염이 되었을 때 손상된 조직을 재생하고 신체를 방어하기 위해 일어나는 선천성 면역반응으로 알려져 있다. 주로 선천면역을 담당하는 대식세포는 lipopolysaccharide, reactive oxygen species와 cytokine 등에 의해 활성화되어 tumor necrosis factor-α. interleukin-1β, interleukin-6 등 염증인자들의 생성에 관여한다. 특히, 산화질소는 superoxide 음이온과 쉽게 반응하고 peroxynitrite와 같은 독성이 강한 산화제를 생성하여 단백질 및 지질의 과산화를 유도하고 세포독성을 일으키는 것으로 보고되고 있다. 따라서 본 연구에서는 항산화 및 항염증 소재를 탐색하기 위해 오미자 (Schisandra chinensis), 꾸지뽕 (Cudrania tricuspidata)을 이용하여 항산화 활성을 평가하고자 하였으며, 세포주를 활용한 세포독성 및 항염증 활성을 확인하고자 하였다. 본 연구는 전북 순창군에서 재배된 오미자, 꾸지뽕을 열 건조(60℃) 통해 건조한 후 분말화하였다. 최적 추출 조건 선정을 위해 다양한 용매 (열수, 증류수, 주정 20, 40, 60%), 온도 (25, 40, 60, 80℃) 및 시간 (1, 2, 3, 4, 5 h) 조건에서 추출된 추출물의 총 폴리페놀 함량을 비교함으로써 최적 조건을 선정하였다. 오미자와 꾸지뽕의 DPPH 및 ABTS radical 소거 활성, 총 플라보노이드 함량을 확인하여 항산화능 및 기능성 성분 함량을 평가하였다. 또한 대식세포주인 Raw 264.7을 활용하여 MTT assay, 산화질소 생성 억제 활성을 확인하여 세포독성 및 항염증 활성을 평가하였다. 실험 결과, 오미자 및 꾸지뽕은 각각 주정 40%, 60℃ 그리고 증류수, 60℃에서 추출 시 가장 높은 총 폴리페놀 함량 (약 98.3 mg GAE/g 및 88.2 mg GAE/g)을 함유하며, DPPH 라디칼 소거 활성은 약 44.6% 및 24.4%, ABTS 라디칼 소거 활성은 약 30.3% 및 40.8%로 확인되었다. 총 플라보노이드 함량은 약 21.80 mg QE/g 및 35.68 mg QE/g으로 확인되었다. 또한 오미자 및 꾸지뽕 기능성 추출물을 100 ug/mL 처리 시 세포 독성이 나타나지 않는 것으로 확인되었으며, NO 생성량을 약 56.3% 및 21.7% 저감시켜 항염증 효능을 나타내는 것으로 확인되었다.

• Land and Housing Review
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• v.14 no.4
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• pp.121-129
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• 2023

In this study, we attempted to reduce CO₂ generated during manufacturing by replacing limestone (CaCO₃), a carbonate mineral used to produce cement clinker, with a decarbonated raw material to which CO₂ is not bound. The raw material for decarbonization was cement paste attached to waste concrete, among various industrial by-products. Waste concrete has cement paste adhered to the aggregate, which cannot be separated efficiently by general crushing and grinding methods. Peeling and grinding methods effectively remove only the cement paste without damaging the original aggregate. The abrasion time, steel ball type, and steel ball ratio were selected as effective factors for Abrasion. An optimal abrasion experiment was conducted to produce waste concrete fine powder containing decarbonated CaO as a cement clinker raw material through an experimental design method. The experiment revealed that the optimal conditions for producing waste concrete fine powder were an abrasion time of 7 minutes, a steel ball size for pulverization of 8 mm, and a steel ball ratio for pulverization of 0.6.

• Tunnel and Underground Space
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• v.34 no.5
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• pp.421-432
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• 2024

Pre-fracturing, a type of pre-conditioning blast, is a method used to weaken rock masses prior to mechanical excavation. In this study, various laboratory tests were conducted on rock core samples obtained from the field to verify the effectiveness of pre-fracturing in controlling the BIDZ (Blast-Induced Damaged Zone) by measuring the physical properties of rock cores obtained from a test site and assessing changes in these properties. In the EDZ (Excavation Damaged Zone) caused by combined excavation using blasting and mechanical excavation, the effect of blasting is generally more significant than that of mechanical excavation, so BIDZ control directly leads to EDZ control. In terms of Poisson's ratio, elastic wave velocity, porosity, density, thermal conductivity, tensile strength and hydraulic conductivity, the BIDZ size in pre-fracturing was smaller than that of conventional blasting. However, no clear reduction in the BIDZ was observed in the case of Young's modulus and uniaxial compressive strength. By applying a theoretical formula predicting the range of tensile cracks caused by blasting and comparing it with the laboratory results, the BIDZ was reasonably predicted. Nonetheless, limitations in accurately predicting BIDZ size were identified due to assumptions regarding ground conditions and charge density in the formula.

• Journal of Korean Society of Disaster and Security
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• v.12 no.4
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• pp.1-13
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• 2019

Recently, as the occurrence frequency of sudden floods due to climate change increased, it is necessary to install the facilities that can cope with the initial stormwater. Most researches have been conducted on the design of facilities applying the Low Impact Development (LID) and the reduction effect on rainfall runoff to examine with 1D or 2D numerical models. However, the studies on the examination about flow characteristics and stability of pipe network systems were relatively insufficient in the literature. In this study, the stability of the pipe network system in rainwater storage tank was examined by using 3D numerical model, FLOW-3D. The changes of velocity and dynamic pressure were examined according to the number of rainwater storage tank and compared with the design criteria to derive the optimal design plan for a rainwater storage tank. As a results of numerical simulation with the design values in the previous study, it was confirmed that the velocity became increased as the number of rainwater storage tank increased. And magnitude of the velocity in pipes was formed within the design criteria. However, the velocity in the additional rainwater storage pipe was about 3.44 m/s exceeding the allowable range of the design criteria, when three or more additional rainwater storage tanks were installed. In the case of turbulence intensity and bottom shear stress, the bottom shear stress was larger than the critical shear stress as the additional rainwater storage was increased. So, the deposition of sediment was unlikely to occur, but it should be considered that the floc was formed by the reduction of the turbulence intensity. In addition, the dynamic pressure was also satisfied with the design criteria when the results were compared with the allowable internal pressure of the pipes generally used in the design of rainwater storage tank. Based on these results, it was suitable to install up to two additional rainwater storage tanks because the drainage becomes well when increasing of the number of storage tank and the velocity in the pipe becomes faster to be vulnerable to damage the pipe. However, this study has a assumption about the specifications of the rainwater storage tanks and the inflow of stormwater and has a limitation such that deriving the suitable rainwater storage tank design by simply adding the storage tank. Therefore, the various storage tank types and stormwater inflow scenarios will be asked to derive more efficient design plans in the future.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.494-501
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• 2010

The purpose of this study was to examine the presence of Bacillus cereus, aerobic bacteria and coliforms in the raw material of infant formulas and investigate the manufacturing process in terms of microbial safety. Among ten kinds of raw infant formula material samples (n=20), Bacillus cereus appeared in two (n=4). Aerobic bacteria were not detected in raw infant formula material or maximum 4.15 log CFU/g. Eleven species of aerobic bacteria were isolated and 76% of them were Sphingomonas paucimobilis, Pseudomonas fluorescens, Rhizobium radiobactor, or Stenotrophomonas maltophilia. A Pearson's correlation analysis revealed that the most influential factors for detecting Bacillus cereus were aerobic bacteria and coliforms. In other words, when the measured values of aerobic bacteria and coliforms were higher, the possibility that Bacillus cereus would appear increased. In a regression model to predict Bacillus cereus, the rate of appearance was correlated with aerobic bacteria and coliforms, and its contribution rate for effectiveness was 86%. Improving microbial quality control by pasteurization, spray dry, popping and extrusion resulted in a decrease in the numbers of Bacillus cereus, aerobic bacteria and coliforms in the raw materials. The results suggest that a hazard analysis and critical control point system might be effective for reducing microbiological contamination.