• Geomechanics and Engineering
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• 제30권3호
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• pp.219-231
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• 2022

Geotechnical materials such as silt, fine sand, or coarse granular soils may be unstable under undrained shearing or during rainfall infiltration starting an unsaturated state. Some researches are available describing the instability of coarse granular soils in drained or undrained conditions. However, there is a need to investigate the instability mechanism of unsaturated silty soil considering the effect of degree of compaction and net confining stress under partially and fully drained conditions. The specimens in the current study are compacted at 65%, 75%, & 85% degree of compaction, confined at pressures of 60, 80 & 120 kPa, and tested in partially and fully drained conditions. The tests have been performed in two steps. In Step-I, the specimens were sheared in constant water content conditions (a type of partially drained test) to the maximum shear stress. In Step-II, shearing was carried in constant suction conditions (a type of fully undrained test) by keeping shear stress constant. At the start of Step-II, PWP was increased in steps to decrease matric suction (which was then kept constant) and start water infiltration. The test results showed that soil instability is affected much by variation in the degree of compaction and confining stresses. It is also observed that loose and medium dense soils are vulnerable to pre-failure instability i.e., instability occurs before reaching the failure state, whereas, instability in dense soils instigates together with the failure i.e., failure line (FL) and instability line (IL) are found to be unique.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.139-142
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• 2000

The SiCp/AC8A composites were fabricated by the pressureless metal infiltration process successfully. The effect of additional Mg, which were mixed with SiC particles to promote interfacial wetting between the reinforcement and matrix alloy, and particle size on the mechanical properties was investigated. By increasing the additional Mg content the hardness of SiCp/AC8A composites was increased due to the hard reaction products, but the bending strength was decreased by the excess reaction of Mg and high porosity level when the additional Mg content is over 7%. The Hardness and bending strength was increased by decreasing the size of SiC particle.

• Journal of Dental Anesthesia and Pain Medicine
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• 제20권2호
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• pp.89-93
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• 2020

We experienced an unusual case of accelerated junctional rhythm with severe hypotension after infiltration of lidocaine containing epinephrine during dental surgery under general anesthesia. The patient's electrocardiogram exhibited retrograde P-waves following the QRS complex, which could be misinterpreted as ST-segment depression. As a temporary measure, administration of ephedrine restored the patient's blood pressure to normal levels. The importance of this case lies in its demonstration of an unexpected and serious side effect of commonly used epinephrine infiltration. This case also highlights the need for accurate interpretation of the electrocardiogram and comprehensive understanding of best practices for patient management.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.175-178
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• 2003

There is a case to use dredged-sea sand as a filling material because of difficulty of obtaining required filling material for tideland reclamation project from the land. At this time, side slope erosion is occurred because the precipitation falling to the top of bank acts as infiltration water when it pass through inside of the semi-permeable filling section. This study has confirmed the declining effect of permeability by conducting permeability test to the condition of mixing of bentonite to the dredged sea-sand. And also this study has confirmed that the above processed-soil could be used as a water-proof layer to protect infiltration of water through the infiltration flow analysis.

• 한국세라믹학회지
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• 제42권8호
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• pp.588-592
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• 2005

The effect of SiC additive on the densification behavior and microstructural change of $TiB_2$ ceramics was investigated. The infiltration and direct mixing with polycarbosilane (PCS), which was converted to SiC by pyrolysis during sintering, were used for the addition of SiC. The addition of Fe enhanced the densification of $TiB_2$, but which resulted in exaggerated grain growth. However, the addition of PCS enhanced the densification and suppressed the exaggerated grain growth of $TiB_2$. Moreover, the addition of PCS using direct mixing was more effective for suppress of grain growth as compare to the addition of PCS using infiltration.

• 연구논문집
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• 통권25호
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• pp.185-192
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• 1995

The solid/liquid interface migration in Nb-doped $SrTiO_3$ and its effect on dielectric properties have been investigated. The specimen sintered in air shows no migration during oxide infiltration treatment in air, whereas the specimen sintered in $5H_2-95N_2$ shows appreciable migration during similar infiltration. In the migrated layers of the specimen sintered in a reducing atmosphere, no cations of the infiltrants are detected by wavelength dispersive spectroscopy. These results show that nonstoichiometry due to the atmosphere change can induce the interface migration as in the case of frequently observed migrations due to solute concentration change. The driving force for the migration is discussed in terms of the coherency strain energy in a thin diffusional oxidized layer of the receding grain. The interface migration caused by nonstoichiometry could be suppressed by preoxidizing grain surfaces before oxide infiltration treatment. The suppression of migration increased the effective dielectric constant of the material.

• 한국구조물진단유지관리공학회 논문집
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• 제4권1호
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• pp.131-138
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• 2000

In this study, physical and engineering properties of ordinary portland cement and microcement were investigated to verify reinforcing effect of underpinning of open caisson foundation by using microcement grouting. Laboratory injection tests such as infiltration and injection in case of seepage for the stream bed soil at ${\bigcirc}{\bigcirc}$ Great Bridge in Seoul were carried out. Field injection tests to reinforce open caisson foundation at ${\bigcirc}{\bigcirc}$ Great Bridge were performed and the ability of application by microcement grouting was evaluated. From the test results, physical and engineering properties of microcement are better than those of ordinary portland cement. Also, the ability of infiltration and solidity in case of seepage is better than that of ordinary portland cement. Therefore, it is concluded that microcement is an excellent material to reinforce open caisson foundation of the existing bridge structure under the water and can be used as underpinning material of general foundations.

• 상하수도학회지
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• 제19권2호
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• pp.221-227
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• 2005

This study has suggested the base data for decision of maintenance ranking and estimation of maintenance effect in the maintenance project of sewers as based on investigation of the defective rate in the sewer through Infiltration/Inflow(I/I) and CCTV analysis. It also analyzed the correlation between I/I and defective rate of sewer. As the result of this study, (1) Defective items of sewer was found out one item each 12.97m with an average. (2) By regression analysis, I/I has high correlation with defective rate of sewer like that $R^2$ is 0.7806. (3) The first thing in the item with bad influence on the I/I was joint badness and secondary was cross connection.

• 한국지반공학회논문집
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• 제33권9호
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• pp.5-22
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• 2017

강우가 사면안정에 미치는 영향을 고려하기 위해 강우의 침투해석을 수행한 후 그 결과를 사면안정해석에 적용하는 안정해석 절차가 널리 사용되고 있다. 강우에 의한 산사태를 예측하기 위해서는 강우의 침투거동을 정확하게 예측하는 것이 필수적이며 이를 위해서는 지반의 불포화 수리특성을 정확하게 파악하는 것이 매우 중요하다. 지반의 불포화 수리특성 중 지반의 보유 수분특성을 나타내는 함수특성곡선에 대해서는 그 중요성이 비교적 널리 알려져 있으며 이를 파악하기 위한 시험방법의 적용도 점차 증가하고 있다. 그러나 지반의 불포화 투수특성을 실험적으로 파악하는 것은 시간과 비용이 많이 소요되므로 지반의 함수특성곡선으로부터 추정하는 방법이 널리 활용되고 있다. 지반의 함수특성이 강우의 침투에 큰 영향을 미치는 것은 널리 알려져 있지만, 함수특성곡선으로부터 추정된 불포화 투수특성이 강우의 침투에 미치는 영향에 대한 연구는 매우 제한적인 형편이다. 본 연구에서는 우리나라에 분포하는 화강풍화토에 대한 함수특성곡선 자료를 바탕으로 투수계수함수를 추정하는 모델이 사면을 통한 강우의 침투 및 사면안정 해석에 어떻게 영향을 미치는지 설명하기 위하여 일차원 침투해석 및 무한사면 해석을 수행하였다. 해석 결과의 분석을 통하여 각 추정모델의 적용성에 대하여 논하였다.

• Journal of Welding and Joining
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• 제10권4호
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• pp.213-221
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• 1992

Al$_{2}$O$_{3}$ ceramic coating layer by gas flame spraying was very porous, therefore it could not have wear and corrosion resistance at all. To get a dense and strong coating layer, a method to infiltrate an alloy into the pores of $Al_{2}$O$_{3}$ ceramic coating was investigated. Cu-Ti alloys, which had good wettability and reactivity with $Al_{2}$O$_{3}$ ceramic, were examined for infiltration. Infiltration of the alloys was performed in vacuum at 1100.deg.C. The melt of Cu-50 at % Ti alloy was well penetrated through the porous $Al_{2}$O$_{3}$ coating and tightly sealed the pores, unbounded area and microcracks in the coating. The alloy melt in the pores reacted with $Al_{2}$O$_{3}$ ceramic to produce a suboxide phase, Cu$_{2}$Ti$_{4}$O. This composite layer which was composed of $Al_{2}$O$_{3}$ and Cu$_{2}$Ti$_{4}$O phase had good microstructure and wear and corrosion resistance. Additionally, microstructures at interfaces between coating layers were greatly improved owing to the effect of vacuum heat treating.