• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.611-616
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• 2001

Increased quantities of sewage sludge coupled with stringent regulations make it important to develope alternatives for residuals management. The use of PARAFIX as a solidifying agent for sewage sludge was investigated by several tests. Basic physicochemical characteristics, strength, permeability, and leaching characteristics were examined. PARAFIX was found to be very effective in reducing permeability, increasing strength, and immobilizing heavy metals. Based on the tests, it Is ascertained that PARAFIX enhances the solidification of sewage sludge. Also sewage sludge solidified with PARAFIX may be used effectively for construction materials.

• 한국농공학회지
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• 제42권3호
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• pp.89-96
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• 2000

Most soft ground in the southern and western coasts in Korea consists of very compressible alluvial deposits. Four samples in these alluvial deposite were selected to manifest the constitutive relations of consolidation. A series of tests were performed to investigate void ratio -effective stress relationand void ratio-coefficient of permeability relation on soil samples obtained at Haenam. Jindo Mankyung and Janghung permeabilities by CRS thoery were similar to directly measured data but those of indirectly computed by $C\upsilon$ shows difference. Several models about compressibility and permeability were compared with test data.

• 한국지반공학회논문집
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• 제19권4호
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• pp.7-14
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• 2003

본 연구는 등방성 투수계수를 갖는 점토에 설치된 압밀촉진 케이슨에 관한 선행 연구를 보다 발전시켜서 비등방성 투수계수를 갖는 점토에서의 압밀촉진 케이슨 기초공법의 타당성을 이론적으로 검증하였다. 투수계수의 비등방성을 고려한 2차원 투수 압밀 방정식의 과잉간극수압에 대한 해석해와 시간계수에 따른 평균압밀도 식을 유도하였다. 비등방성 투수계수비가 5, 10, 50인 경우, $\xi$=0.1인 단면에서 평균압밀도 90%에 도달하는 시간은 기존 케이슨에 비해 각각 약 8배, 13배, 47배 단축되었다. 이는 지반의 비등방성 투수계수비가 클수록 압밀촉진 케이슨 기초공법이 압밀에 소요되는 시간을 단축시키는데 효과적임을 의미한다. 또한 본 연구에서는 해석단면의 깊이에 대한 폭의 비 및 비등방성 투수계수비에 따른 전체 해석단면에서의 평균압밀도에 대한 그래프를 제시하였으며, 이를 이용하여 평균압밀침하량을 쉽게 산정할 수 있다.

• Computers and Concrete
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• 제19권4호
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• pp.357-363
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• 2017

This paper conveys the effects of fly ash and silica fume incorporated in concrete at various replacement ratios on the durability properties of concretes. It is quite well known that concrete durability is as much important as strength and permeability is the key to durability. Permeability is closely associated with the voids system of concrete. Concrete, with less and disconnected voids, is assumed to be impermeable. The void system in concrete is straightly related to the mix proportions, placing, compaction, and curing procedures of concrete. Reinforced concrete structures, particularly those of subjected to water, are at the risk of various harmful agents such as chlorides and sulfate since the ingress of such agents through concrete becomes easy and accelerates as the permeability of concrete increases. Eventually, both strength and durability of concrete reduce as the time moves on, in turn; the service life of the concrete structures shortens. Mineral additives have been proven to be very effective in reducing permeability. The tests performed to accomplish the aim of the study are the rapid chloride permeability test, pressurized water depth test, capillarity test and compressive strength test. The results derived from these tests indicated that the durability properties of concretes incorporated fly ash and silica fume have improved substantially compared to that of without mineral additives regardless of the binder content used. Overall, the improvement becomes more evident as the replacement ratio of fly ash and silica fume have increased. With regard to permeability, silica fume is found to be superior to fly ash. Moreover, at least a 30% fly ash replacement and/or a replacement ratio of 5% to 10% silica fume have been found to be highly beneficial as far as sustainability is concerned, particularly for concretes subjected to chloride bearing environments.

• 한국지반공학회논문집
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• 제19권6호
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• pp.363-369
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• 2003

액상화후 과잉간극수압 소산양상을 파악하고 액상화를 겪는 지반의 침하량을 예측하는데 필요한 진동하중이 작용하는 동안의 포화된 모래지반의 투수계수 변화를 추정하기 위하여, 액상화 가능성이 큰 5종류의 모래에 대해 1-g 진동대시험을 수행하였다. 시험과정중에 깊이별 과잉간극수압과 지표면 침하량을 계측하였다. 액상화후 계측된 과잉간극수압 소산곡선을 침강이론으로 선형모사하였고 선형모사된 소산곡선의 기울기를 분석함으로써 소산속도와 입도특성치와의 상관관계를 얻었다. 이러한 상관관계와 계측된 침하량을 침강이론에서 제안한 소산속도식에 대입하여 소산과정중 투수계수를 역산하였고 산정된 소산과정중 투수계수를 이용하여 진동하중이 작용하는 동안의 투수계수 변화를 추정하였다. 액상화후 과잉간극수압의 소산속도는 유효입경을 균등계수로 나눈 값에 선형적 상관관계를 갖는 것으로 나타났으며, 이러한 상관관계를 이용하여 구한 소산과정과 액상화동안의 투수계수는 원지반의 초기투수계수에 비해 각각 1.1∼2.8배, 1.4∼5배 증가하였다 그리고 이러한 증가 정도는 시험모래의 유효입경이 클수록 균등계수가 작을수록 더 커짐을 알 수 있었다.

• 한국농공학회지
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• 제17권3호
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• pp.3833-3839
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• 1975

The object of this experiment is to find out some flow characteristics of water through sand layer, to prevent moving sands in the filters of the fill Dam, infiltration gallery, well and Deversion Weir. This experiment was accomplished with different particle Sizes of Six Samples and different hydraulic gradient. The results obtained are Summarized as follows. 1. The critical hydraulic gradients for laminar flow was found to be between 1 and 2 when the sand used had the effective diameter, D10 of between 0.18cm and 0.45cm. 2. The critical hydraulic gradients for different particle sizes of sands were varied considerably. 3. There was a negative correlation between critical hydraulic gradient and critical Velocity, and between effective particle diameter D10 and critical hydraulic gradient respectively. 4. In spite of relatively small variation of void ratio of sands used, the values of the coefficient of permeability varied considerably. There was a negative correlation between coefficient of permeability and void ratio.

• Journal of Pharmaceutical Investigation
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• 제24권3호spc1호
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• pp.19-25
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• 1994

The single-pass perfusion technique was employed in order to investigate the effect of water flux from the rat jejunum in the normal experimental conditions. Our results suggested that water flux below ${\pm}0.75%/cm$ of jejunal length was considered normal. Water flux was $-0.131\;{\pm}\;0.311%/cm$ of jejunal length in a citrate buffer and should be corrected in order to determine the permeabilities of the compounds. Perfusion rate up to 0.5 ml/min had no effects on the permeability of ampicillin. Neither the effective permeabilities nor the wall permeabilities of aminopenicillins were influenced by water flux during experiments in rats.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.477-478
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• 2010

Concretes with binary blends of Portland cement, silica fume, fly ash and ground granulated blast furnace slag were produce to investigate their effects on compressive strength and chloride transport in rapid chloride permeability. Ten different mix of concrete with 0.45 water/binder were produced. Portland cement was replacedby: (i) 10%, 20%, 30% Fly ash (ii) 3%, 5%, 10% Silica Fume (iii) 20%, 40%, 60% GGBS. Compressive strength of concrete with the pozzolans is higher compared to that of the Portland cement concrete. The test results indicate the fly ash, silica fume, and ground granulated furnace slag greatly reduce the rapid chloride permeability of concrete. It was concluded that pozzolans are more effective to reduce chloride permeability of concrete.

• 약학회지
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• 제47권3호
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• pp.154-158
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• 2003

Lincomycin, a selective tyrosinase blocker, has been thought to be effective in the treatment of melanogenesis, ephelis, post inflammatory pigmentation, and facial discoloration. In an attempt to develop a transdermal perparation for lincomycin, this study was designed to examine the appropriate contents of various surfactants and ethanol in the cream preparation. Frans type diffusion cell was used to investigate permeation efficiency of the preparation, and lincomycin in the receptor phase was measured by HPLC. After having a 1.5 hrs of leg time, the permeability of lincomycin was rapidly increased by adding surfactants, and varied with different types of surfactants after 10 hrs, the permeability of Brij 56$^{(R)}$ preparation (501.4$\pm$45 $\mu\textrm{g}$/mι) was greater than that either of Labrasol$^{(R)}$ (263.9$\pm$33.7 $\mu\textrm{g}$/mι) or Tween$^{(R)}$20(386.2$\pm$26.7 $\mu\textrm{g}$/mι). Ethanol also increased the permeability of lincomycin.mycin.

• Journal of electromagnetic engineering and science
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• 제13권2호
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• pp.134-136
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• 2013

This paper examines various aspects of the electromagnetic responses of the ring resonator located in the transverse electromagnetic cell. In addition, an equivalent circuit for the ring resonator is proposed and analyzed based on the electromagnetic phenomenon of the resonator. The equivalent circuit was simply modeled based on the concept of magnetization. A method for achieving a wider operating bandwidth of the negative permeability is provided. The ring resonator with its resonant frequency of 13.56 MHz was designed and its characteristics were examined in terms of S-parameters, effective permeability, loss rate, bandwidth, etc. The circuit and electromagnetic simulation results show an excellent agreement as well as that of theory.