• Title/Summary/Keyword: composite method

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Estimation of Seismic Performance and Earthquake Damage Ratio of Existing Reinforced Concrete Buildings in Japan (일본의 기존 철근콘트리트건물의 내진성능 및 지진피해율의 평가)

  • 이강석;이리형
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.1
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    • pp.63-74
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    • 2000
  • The main objective of this paper is to apply as the basic data for development of a methodology to discuss the future earthquake preparedness measures in Korea by investigating the concept and applicabilities of the Japanese Standard for Evaluation of Seismic Performance of Existing RC Buildings developed in Japan among the methodologies of all the countries of the world. This paper describes the seismic performance, Is-index, of existing RC buildings in Tokyo, Japan evaluated by the Japanese Standard, also the relationships between Is-index distribution of existing RC buildings in Tokyo and that of Shizuoka and Chiba Prefecture reported already in reference[4][5][6] are investigated. And from the comparison with Is-index to buildings damaged by earthquakes experienced in Japan, the damage ratio due to severe earthquake of 3 districts mentioned above is estimated based on the probabilistic point of view. The results of this study can be utilized to identify urgently required earthquake preparedness measures with highest priority in existing RC buildings, and the methodology to evaluate the seismic performance of existing RC buildings in Japan, statistics analysis method and the methodology to estimate earthquake damage ratio based on the probabilistic point of view shown in this study can be recommended to develop a methodology to discuss the future earthquake preparedness measures in Korea.

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Study of the Molecular Reorientation in Ammonium Sulfate by Neutron Scattering

  • Kim, Huhn-Jun
    • Nuclear Engineering and Technology
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    • v.4 no.4
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    • pp.306-321
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    • 1972
  • Molecular reorientation in (NH$_4$)$_2$SO$_4$, has been studied by cold neutron scattering. For T=300$^{\circ}$K data, the isolated quasielastic spectra and form-factors at various scattering angles are compared with four reorientational models based on SKOLD theory. Front these, it is concluded that the NH$_4$ions are performing either 3-fold four axes or 2-fold three axes reorientation with $\tau$$_{c}$=2.0$\times$10$^{-11}$ sec. The temperature dependence of f. is studied over 100$^{\circ}$K-413$^{\circ}$K and for the high-temperature phase, the widths of composite spectra are compared with the results from NMR relaxation measurements. All the results have shown that the neutron scattering method is capable of giving detalis of the reorientational modes in solids and therefore some discussions are given on the application of this method. A study of the form-factor is applied for NH$_4$I (Phase I) by comparing the measurement with the calculation based on free rotation approximation and proposed a reorientation model of NH$_4$ ions in the octahedral potential cage with $\tau$$_{c}$$\leq$10$^{-12}$ sec. Also a brief theoretical prediction for the effect of reorientational motions on the inelastic spectrum is discussed.sed.

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Application Assessment of Passive Sampling to Monitor Polybrominated Diphenyl Ethers in Water Environment as Alternative Sampling Method for Grab Sampling (수계 중 폴리브롬화 디페닐에테르 모니터링을 위한 Passive Sampling 적용 및 그랩 시료채취법의 대체 활용가능성 평가)

  • Kim, Un-Jung;Seo, Chang Dong;Im, Tae-Hyo;Oh, Jeong-Eun
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.1
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    • pp.45-51
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    • 2015
  • PBDEs (polybrominated diphenyl ehters) are rarely dissolved in water due to their strong hydrophobicity and large molecular mass so not many researches were done in aqueous environment compared to other environmental compartments. However, the mass loading from wastewater treatment plant into aquatic environment, re-suspension from bottom sediment and partitioning from floating particles and colloids may not be negligible. It is, therefore, important but also difficult to investigate PBDEs in water environment. Recent overcoming resolution towards this barrier to monitor hydrophobic organic compounds in aquatic environment is using passive sampling technique like semipermeable membrane device. By using passive sampling, it might be possible to obtain long-term reproducible monitoring result and detect the trace amounts of PBDEs, with controlling fluctuation of surrounding environmental factors during the sampling event. So therefore, this study is purposed to confirm the possibility of using SPMD (semi-permeable membrane device) as water monitoring tool. Grab samples, composite samples and SPMDs were applied in river bank to evaluate the concentration difference and temporal fluctuation by various water sampling method, and to assess the water concentration prediction capability of SPMD for the PBDEs.

A Study on the Evaluating Method the most Favorable Mixture Proportion of Blended Fine Aggregate for Effective Application of Recycled Aggregate (재생골재의 효율적인 활용을 위한 혼합잔골재의 최적배합평가방법에 관한 연구)

  • Han, Cheon-Goo;Yoon, Gi-Won;Lee, Gun-Cheol;Park, Yong-Kyu
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.2 no.1
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    • pp.113-119
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    • 2006
  • It is now established that more than two types of blended aggregate have beneficial effects on quality and supply of concrete in the long run. However, studies on blended aggregate have not widely been progressive and the evaluation method of its most favorable mixture proportion is still needed. Therefore this study investigated the most favorable mixture proportion through the physical experiment of fresh and hardened state's cement mortar, in response to three types of composite ratio, natural fine aggregate(Ns), crushed fine aggregate(Cs) and recycled fine aggregate(Rs). Test showed that increase of blending ratio of Ns and Cs improved fluidity of mot1ar. For the properties of compressive and flexural strength, mortar blending Ns and Cs properly, exhibited similar value to one using only Cs, while mortar mixing Rs showed lower strength value as less as 6% of control one. Mortar using only Rs exhibited the largest drying shrinkage value. In addition, even thought it is not a clear quantitative analysis, technical-imaging-skill presenting the most favorable mixture proportion 3-dimensionally is proposed in this research, in order to notify the proportion easily.

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A Fundamental Study on Induction Technology of Separation Behavior Using Two-sided Adhesion of Joint of Composites Waterproofing System (시트-도막 복합방수공법의 접합부 2면 접착을 통한 분리거동 유도 기술에 관한 기초적 연구)

  • Park, Jin-Sang;Lee, Tae-Yang;Kim, Dong-Bum;Park, Wan-Goo;Heo, Neung-Hoe;Oh, Sang-Keun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.3 no.3
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    • pp.212-219
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    • 2015
  • This study focuses evaluating the efficiency and performance evaluation of composite type sheet-membrane waterproofing method that utilizes a separation behavior inducement system designed to resolve the chronic problems of disintegration and damage of overlap areas of waterproofing layers. As the result of the test, the tensile strength value was at 13.8N/mm and elongation rate at 587% for the separation behavior inducement type specimen, and the compared specimens had 14.2N/mm for tensile strength and 335% for elongation rate. For the separation behavior adhesion method specimen, when tensile stress or displacement occurred, the Zero-Span tension occurrence did not follow, which resulted in that the bottom sheet layer and the top membrane layer did not simultaneously becoming damaged. When undergoing the top and bottom layers were separated through separation behavior due to lack of flexibility, the bottom layer began to damage at the primary stage, and with the allowed boundary the upper membrane layer began to display flexibility and showed continuous displaced resulting in secondary phase damaging.

Characteristics on Shear Strength and Clogging Phenomenon of Bottom Ash and Rammed Aggregate Mixture Compaction Pile (쇄석과 저회의 혼합다짐말뚝의 전단강도와 Clogging 현상 규명)

  • Lee, Dongyeup;Kang, Hyongnam;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.3
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    • pp.33-41
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    • 2010
  • The rammed aggregate compaction pile method is widely used as soft ground improvement method because of the installed piles improve not only overall composite capacity but also discharge capacity. But the discharge capacity is declined when the clogging is generated due to the clay penetration into voids of rammed aggregate compaction pile with the time elapsed. The purpose of this study is to reduce the clogging problem occurred in rammed aggregate compaction pile constructed in the soft ground and to minimize voids of rammed aggregate compaction pile. The proper mixing ratio was determined which is based on the results of the large scale direct shear tests conducted to get strength and permeability as optimum mixing ratio of crushed stone and bottom ash. The test results indicated that the highest internal friction angle was obtained at 80:20 mixing ratio of crushed stone and bottom ash. The internal friction angle was declined when the mixing ratio of the bottom ash increased over 20%. The results of the clogging tests, presented that the mixture of 80:20 crushed stone and bottom ash is highest effective of clogging than ratio of pure crushed stone.

Verification of Durability of Electromagnetic Metamaterial Absorber in Temperature Varying Environment for Its Application to Integrated Mast of Next-Generation Destroyer (차기구축함 통합마스트에 적용을 위한 전자기파 메타물질 흡수체의 온도 환경 내구성 검증)

  • Ra, Young-Eun;Kim, Yongjune;Jung, Hyun-June;Park, Pyoungwon;Jo, Jeongdai;Lee, Joonsik;Kim, Myungjoon;Jung, Joonkyo;Lee, Gun-Min;Lee, Jong-Hak;Lee, Hak-Joo
    • Journal of IKEEE
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    • v.24 no.1
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    • pp.347-353
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    • 2020
  • In this paper, the durability of an electromagnetic metamaterial absorber is verified in a temperature varying condition mimicking a maritime environment for the purpose of applying it to reduce the radar cross section of an integrated mast of the next-generation destroyer. To validate the durability, the reflectance of the electromagnetic metamaterial absorber was measured after storing it in a chamber that can control the temperature according to Procedure I of Method 501.7 included in MIL-STD-810H. Before and after the environmental test, both of the measured reflectances were retained less than -10 dB over the X band, that can guarantee the stealth functionality.

A Trend of Back Ground Surface Settlement of Braced Wall Depending on the Joint Dips in Rocks under the Soil Strata (복합지반 굴착 시 암반층 절리경사 각도별 흙막이 벽체 배후 지표침하의 경향)

  • Bae, Sang-Su;Lee, Sang-Duk
    • Journal of the Korean Geotechnical Society
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    • v.32 no.11
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    • pp.83-96
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    • 2016
  • The surface settlement of the back ground of a braced wall due to the ground excavation has the great influence on the safety of the surrounding area. But it is not easy to predict the settlement of the surrounding area due to proud excavation. Estimation of the settlement of the surface ground induced by the deformation of the braced wall is performed by FEM and empirical method (Peck, Clough etc). In this research, surface settlement of the back ground braced wall depending on the joint dips in rocks during excavating the composit ground was measured at the large scale model test (standard: $0.3m{\times}0.3m{\times}0.5m$). The scale of model test was 1/14.5 and the ground was excavated in ten steps. Earth pressure on the braced wall and ground surface settlement on the back ground of a braced wall were investigated. The surface settlement during the excavation depended on the joint dips in rocks on of the ratio of rock layer. Maximum earth pressure and maximum surface settlement were masured at the same excavation step. In accordance with the increase of the rock layer dips and rock layer ratio, the ground surface settlement increased. The maximum ground surface settlement was 17 times larger at 60 degree joint dips in rocks than that of the horizontal ground conditions. And the position of the maximum surface settlement by empirical method was calculated at the point, which was 17%~33% of excavation depth. In accordance with the increase of the rock layer dips and rock layer ratio, the ground maximum surface settlement increased. The ground surface settlement of composite ground is smaller than that of the empirical.

Fabrication and Property Evaluation of Tubular Segmented-in-Series Solid Oxide Fuel Cell (SOFC) (세그먼트 관형 SOFC의 제작 및 특성 평가)

  • Yun, Ui-Jin;Lee, Jong-Won;Lee, Seung-Bok;Lim, Tak-Hyoung;Park, Seok-Joo;Song, Rak-Hyun;Shin, Dong-Ryul;Han, Kyoo-Seung
    • Korean Chemical Engineering Research
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    • v.50 no.3
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    • pp.562-566
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    • 2012
  • A novel design of tubular segmented-in-series(SIS) solid oxide fuel cell (SOFC) sub module was presented in this paper. The tubular ceramic support was fabricated by the extrusion technique. The NiO-YSZ anode and the yttria-stabilized zirconia (YSZ) electrolyte were deposited onto the ceramic support by dip coating method. After sintering at $1350^{\circ}C$ for 5 h, a dense and crack-free YSZ film was successfully fabricated. Also, the multi-layered cathode composed of LSM-YSZ composite, LSM and LSCF were coated onto the sintered ceramic support by dip coating method and sintered at $1150^{\circ}C$. The performance of the tubular SIS SOFC cell and sub module electrically connected by the Ag-glass interconnect was measured and analysed with different fuel flow and operating temperature.

Biological Activities or oat soluble $\beta$-glucans (귀리 수용성 $\beta$-glucan의 생물활성)

  • 강태수;정헌상;박희정;이명렬;공영준;정익수
    • Food Science and Preservation
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    • v.10 no.4
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    • pp.547-553
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    • 2003
  • To develop the health and functional food material from oats, this study was conducted to determine the biologiral activities(antibacterial, antioxidative and mtltmor effects) of oat bran's soluble ${\beta}$-glucans obtained from oat bran concentrate(OBC) by central composite experimental design. The antibacterial effect of oat's ${\beta}$-glucans in the concentration of 250, 500$\mu\textrm{g}$/disc was not detected by paper disc method, and no antioxidative effect of them in the concentration of 5% by electron donating ability. The growth inhibition on tumor cell lines of oat's soluble ${\beta}$ -glucans was significantly higher in the experimental fraction of No. 7(temperature 45$^{\circ}C$, ethanol 15%, pH 6) than the other fractions(p<0.05). The maximal values of growth inhibitions on AGS, Hep3B and A549 cell lines in the cancentration of 1mg/ml are 59%, 58% and 54% respectively. In addition, the inhibition effect on three tumor cell lines of No. 1(temperature 5$^{\circ}C$, ethanol 5%, pH 6) was relatively high. From the results of response surface methodology, as the values of independent variables changed, they influenced the growth inhibition effect on this cell lines. With this on work further research is required to clarify antitumor effects.