• 터널과지하공간
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• 제5권2호
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• pp.89-94
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• 1995

Regression analysis and a comparative study were carried out for 52 blast vibration data which were monitored by changing the monitoring distance and charge per delay. The results are as follows: 1) The square and cube root scalings and general equation which have a confidence level at the point of 90% and 99% are V90=33300(SD)-2.026 , V90=23600(SD)-1.993, V90=26300W0.755 R-2.007 and V99=48400(SD)-2.026, V99=34000(SD)-1.993 , V99=38100W0.755R-2.007, respectively. 2) There is need to decide the allowable max. charge weight per delay considering the cross points comparatively of the nomogram constructed using several predictived equations. 3) It is necessary to derive the predictive equation on the basis of blast vibration level monitored in field and to decide safe vibration level and the confidence level.

• 대한수의학회지
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• 제31권1호
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• pp.49-53
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• 1991

The present study has been carried out to investigate the optimal condition on lymphocyte blastogenesis of rabbit lymphocytes, whole blood culture and microculture system in conjunction with a semiautomatic multiple sample harvester(SAMSH) was used to study the In vitro optimal condition of rabbit lymphocytes. Data were presented to show many variables that are involved in studying the phytohemagglutinin(PHA) and lipopolysaccharide(LPS) response of rabbit lymphocyte in a microculture system. Analysis indicated that the conditions for optimal PHA as measured by incorporation of $^3H$-TdR include: (1) use of RPMI-1640 as culture medium. (2) use of $6{\mu}g$ of PHA, per culture. (3) 48-hours culture period. Conditions for optimal stimulation with LPS mitogen were similar to those used for PHA.

• Structural Engineering and Mechanics
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• 제39권2호
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• pp.287-301
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• 2011

This paper is focused on the residual capacity of steel columns, as a damage criterion. Load-Impulse (P-I) diagrams are frequently used for analysis, design, or assessment of blast resistant structures. The residual load carrying capacity of a simply supported steel column was derived as a damage criterion based on a SDOF computational approach. Dimensionless P-I diagrams were generated numerically with this quantitative damage criterion. These numerical P-I diagrams were used to show that traditional constant ductility ratios adopted as damage criteria are not appropriate for either the design or damage assessment of blast resistant steel columns, and that the current approach could be a much more appropriate alternative.

• Structural Engineering and Mechanics
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• 제32권2호
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• pp.301-320
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• 2009

Damage assessment for buried structures against an internal blast is conducted by considering the soil-structure interaction. The structural element under analysis is assumed to be rigid-plastic and simply-supported at both ends. Shear failure, bending failure and combined failure modes are included based on five possible transverse velocity profiles. The maximum deflections with respect to shear and bending failure are derived respectively by employing proper failure criteria of the structural element. Pressure-Impulse diagrams to assess damage of the buried structures are subsequently developed. Comparisons have been done to evaluate the influences of the soil-structure interaction and the shear-to-bending strength ratio of the structural element. A case study for a buried reinforced concrete structure has been conducted to show the applicability of the proposed damage assessment method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.77-78
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• 2011

This study is analysis of effect of binder types and replacement ratio on the properties of blast furnace slag mortar using the recycled fine aggregates. The results of the study were was follows. Compressive strength was increased according to an increase in replacement ratio of fine particle cement and gypsum. Absorption was reduced according to an increase in replacement ratio of fine particle cement and recycled aggregate fine powder.

• Advances in concrete construction
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• 제6권6호
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• pp.611-629
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• 2018

The objective of present study is to investigate the effect of granulated blast furnace slag (GBS) as partial substitution of natural sand on behaviour of cement mortar. For this, the methods of factorial design with water cement (w/c) ratio and incorporation percentages of GBS as replacement of natural fine aggregate i.e., GBS(%) as factors are followed. The levels of factor w/c ratio are fixed at 0.4, 0.45, and 0.5 and the levels of factor GBS(%) are kept fixed as 0%, 20%, 40%, 60%, 80% and 100%. The compressive strength (CS) of mortar after 3, 7, 14, 28, 56 and 90 days, and water absorption (WA) are chosen as responses of the study. Analysis of variance (ANOVA) of experimental results has been carried out and those are illustrated by ANOVA tables, main effect and interaction plots. The results of study depict that the selected factors have substantial influence on the strength and WA of mortar. However, the interaction of factors has no substantial impact on CS and WA of mixes.

• 드라이브 ㆍ 컨트롤
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• 제19권1호
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• pp.8-15
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• 2022

The demand for the re-painting of steel bridges is increasing, but surface treatment is still centered on human resources for on-site re-painting processes. Worker safety accidents continue to occur because the work is performed in a narrow space. Recently, PS balls with excellent surface treatment have been used for blasting, but the working environment is poor due to the large amount of dust generated. In this study, an effective surface treatment method using impeller blasting equipment was developed. The correlation between steel ball size, impeller rotation speed, and exposure time was studied to optimize the efficiency of the surface treatment.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.151-152
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• 2023

Lightweight aggregates has a dry specific gravity of 2.0 or less, which is lower than natural aggregates. Lightweght aggregate is efficient for weight reduction but has low compressive strength. In this study, EIS(electrochemical Impedance Spectroscopy) was used to confirm the ITZ(Interfacial Transition Zone) between the lightweight aggregate and cement paste according to the coated of blast furnace slag powder. As a result of EIS measurement, the correlation between ITZ characteristics and compressive strength was determined. The phase angle of EIS was different depending on the blast furnace slag powder coated of the lightweight aggregate. The surface-cotead lightweight aggregate was improved and the ITZ was strengthened.

• 대한토목학회논문집
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• 제29권5A호
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• pp.557-564
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• 2009

최근, 테러 및 전쟁과 관련된 폭발사고가 빈번히 발생하고 있으며, 특히 도심지에서는 이러한 폭발사고로 인해 인명피해 뿐 아니라 주요 시설물에도 큰 손상이 가해져 제2차, 3차의 피해가 발생하게 된다. 폭발사고에 대하여 인명 및 시설물을 안전하게 보호하기 위해서는 기본적으로 구조물에 가해지는 폭발하중 효과에 대한 이해가 필요하다. 폭발하중은 매우 빠른 시간 내에 콘크리트 구조물에 큰 압력으로 작용하는 하중이므로 변형률 속도와 구조물의 국부적인 손상을 고려하여 동적응답을 평가해야 한다. 일반적으로, 콘크리트는 다른 건설재료에 비해 상대적으로 높은 폭발저항성을 가진 재료로 알려져 있다. 그러나 폭발실험이라는 특수한 실험조건으로 인하여 국내외적으로 실험에 관련된 정보 및 결과 공유가 상당히 제한적으로 이뤄지고 있는 실정이다. 그러므로 본 논문에서는 폭발에 의한 압력하중이 철근콘크리트 구조물에 미치는 영향과 방호성능을 평가하기 위하여 국방과학시험연구소 다락대 시험장에서 $1.0m{\times}1.0m{\times}150mm$의 철근콘크리트 슬래브 구조물을 제작하여 시편으로부터 높이 1.5 m에서 TNT 9 lbs와 TNT 35 lbs으로 예비시험을 수행하였으며, 동일한 이격거리(standoff)에서 ANFO 35 lbs으로 본 실험을 수행하였다. 이는 국내 최초 민간에서 수행되어진 실험으로써, 첫 번째 논문에서는 폭발실험을 하기 위한 기본적인 실험 구성 및 구조물의 거동을 측정하기 위한 계측장비 구성에 대하여 검토하여 계측 시스템의 구축 및 폭파시험 수행절차를 구축하고자 한다. 센서, 시그널 컨디셔너, DAQ시스템, 소프트웨어로 구축된 계측 시스템을 바탕으로 정립된 폭파시험 수행절차는 향후 국내의 방호설계 및 폭발하중을 받는 구조물의 효과적인 거동계측 등 관련 연구분야의 기초자료가 될 것이라고 판단되는 바이다.

• 한국인터넷방송통신학회논문지
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• 제11권4호
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• pp.113-118
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• 2011

서열 상동성 분석은 생명현상에 관여하는 물질을 정렬, 색인하여 데이터베이스 하는 것으로, 생명정보학의 유용성을 입증하는 분야이다. 본 논문에서는 구조가 복잡한 진핵생물의 서열 패턴을 단백질 서열로 변환하기 위해 은닉마르코프모델을 이용하는 GenScan 프로그램을 이용한다. 서열상동성 분석 중 최소거리 탐색 문제는 문제의 크기가 커지면 계산량이 기하급수적으로 증가하여 정확한 계산이 불가능해진다. 따라서 유사한 아미노산간의 치환과 상이한 아미노산간의 치환 점수를 차등화한 점수표를 적용하고, 은닉마르코프모델 등을 적용해 정교한 전이 확률모델을 적용한다. 변환된 서열을 서열 상동성 분석을 위해 사용되는 blast p를 이용하여, 은닉 마르코프 모델을 도입함으로 인해 단백질 구조 서열로 변환하는 데에 있어서 우수한 기능을 제공함을 알 수 있다.