• 터널과지하공간
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• 제34권4호
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• pp.312-329
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• 2024

지하 심부를 대상으로 하는 에너지 저장 및 개발, 방사성폐기물 처분 등 여러 지하연구사업들에서 심부 암반대수층 내 지하수 흐름의 주요 통로가 되는 투수성 암반균열의 특성 정보들은 연구시설의 설계와 건설 그리고 운영에 있어 중요한 평가 요소로 고려된다. 국내에는 심도가 매우 깊은 암반시추공에서 투수성 암반균열의 위치와 수리특성, 균열 사이에 발생할 수 있는 지하수 유동 양상에 관한 연구와 데이터베이스가 매우 부족한 실정이다. 본 논문에서는 지온경사와 양수시험 자료분석을 통해 심부 암반대수층 내 투수성 암반균열의 수리특성을 평가하였다. 먼저 온도검층을 통해 심부 지온 분포를 확인하고, 심도별 온도자료를 이용하여 선형회귀분석을 통해 지온경사를 도출하였다. 또한 양수시험을 통한 용출온도를 이용해, 균열암반에 대한 수리특성을 분석하였다. 최종적으로 이러한 물리검층과 수리시험 자료를 통합 분석함으로써 투수성 암반균열의 잠재적 위치와 수리특성, 그리고 시추공 내 지하수 흐름을 평가하였다. 본 연구에서 제안된 심부 투수성 암반균열의 특성평가 과정과 결과들은 심부 암반대수층을 대상으로 하는 지하연구사업들의 성공적인 수행을 위한 기초 자료로 활용될 것으로 기대된다.

• 대한토목학회논문집
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• 제40권5호
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• pp.485-496
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• 2020

잠제와 인공리프와 같은 수중구조물은 연안역의 침식 등의 대책으로 일반적으로 사용되고 있다. 본 연구에서는 Tetrapod로 제체를 형성한 투과형 수중구조물을 대상으로 파랑의 전달에 대한 2차원 수리실험을 수행하였다. 수리실험은 서로 다른 상대여유수심, 상대여유고, 상대상단폭 및 파형경사 등을 적용하여 수행되었다. 수리실험결과를 이용하여 투과형 수중구조물에 의한 파고전달계수 산정식을 제안하였다. 제안된 경험식은 파고전달계수를 충분한 정도로 예측함을 확인하였으며, 기존 경험식을 개선하였다.

• 한국농공학회지
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• 제41권2호
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• pp.104-110
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• 1999

This study was performed to evaluate the properties of permeable polymer concrete with fly ash and CaCO3. The following conclusions are drawn. The static modulusof elasticity is in the range of 1.19 $\times$105 ~1.49$\times$105 kgf/$\textrm{cm}^2$, which is approximately 53 ~56% of that of the normal cement concrete. The oission's number of permeable polymer concrete is in the range of 3.95 ~6.53, which is less than that of the normal cement concrete. The dynamic modulus of elasticity is in the range of 1.29$\times$105 ~1.59$\times$105 kgf/$\textrm{cm}^2$, which is approximately less compared to that of the normal cement of the static modulus . Fly ash 50% and CaCO3 50% filled permeable polymer concrete has showed higher dynamic modulus. The water permeability is in therange of 3.971 ~4.393$\ell$ /$\textrm{cm}^2$/h, and it is largely dependent upon the mix design. These concrete can be used to the structures which need water permeability.

• 농업과학연구
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• 제23권1호
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• pp.51-60
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• 1996

This study was performed to evaluate the effects of filler on engineering properties of permeable polymer concrete with unsaturated polyester resin. The following conclusions were drawn; 1. The unit weight was in the range of $1.804{\sim}1.919t/m^3$, the weights of those concrete were decreased 17~22% than that of the normal cement concrete. 2. The highest strength was achieved by stone dust filled permeable polymer concrete, it was increased 17% by compressive, 147% by tensile and 188% by bending strength than that of the normal cement concrete, respectively. 3. The ultrasonic pulse velocity was in the range of 2,722~3,060m/sec, which was showed about the same compared to that of the normal cement concrete. Stone dust filled permeable polymer concrete was showed higher pulse velocity. 4. The water permeability was in the range of $3.076{\sim}4.152{\ell}/cm^2/h$, and it was larglely dependent upon the mix design. These concrete can be used to the structures which need water permeability. 5. The compressive strength, tensile strength, bending strength and ultrasonic pulse velocity were largely showed with the increase of unit weight. But, it was decreased with the increase of water permeability, respectively.

• 한국도로학회논문집
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• 제17권1호
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• pp.69-75
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• 2015

PURPOSES : The objective of this study is to evaluate the effectiveness of a geogrid reinforced subbase of permeable flexible pavement structures with respect to permanent deformation. METHODS : Experimental trials employing a repeated triaxial load test scheme were conducted for both a geogrid reinforced subbase material and a control specimen to obtain the permanent deformation properties based on the VESYS model. Along with this, a finite element-based numerical analysis was conducted to predict pavement performance with respect to the rutting model incorporated into the analysis. RESULTSAND CONCLUSIONS : The results of the experimental study reveal that the geogrid reinforcement seems to be effective in mitigating permanent deformation of the subbase material. The permanent deformation was mostly achieved in the early stages of loading and then rapidly reached equilibrium as the number of load applications increased. The ultimate permanent deformation due to the geogrid reinforcement was about 1.5 times less than that of the control specimen. Numerical analysis showed that the permeable, flexible pavement structure with the geogrid reinforced subbase also exhibits less development of rutting throughout the service life. This reduction in rutting led to a 20% decrease in thickness of the subbase layer, which might be beneficial to reduce construction costs unless the structural adequacy is not ensured. In the near future, further verification must be conducted, both experimentally and numerically, to support these findings.

• 한국생산제조학회지
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• 제24권6호
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• pp.660-666
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• 2015

To avoid radiation exposure from repeated x-rays taken during orthopedic surgery, an x-ray permeable teleoperated Stewart platform for orthopedic fracture surgery was developed. This system is composed of a user interface device and a teleoperated operational robot, both of which use a Stewart platform mechanism. The links of the operational robot are made from an x-ray permeable material, polycarbonate, to minimize the interference. The forward and inverse kinematics algorithm applied and the structural reliability were both verified through an analysis using commercial engineering software. To monitor the operating status in real time and stop the device during an emergency, a monitoring software was developed. The performance of the x-ray permeable teleoperated Steward platform was validated experimentally.

• Journal of Pharmaceutical Investigation
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• 제39권4호
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• pp.269-273
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• 2009

The objective of this investigation was to develop a gastro-retentive(GR) dosage form of gabapentin and was to evaluate of its dissolution characteristics. GR tablet consists of expandable core tablet matrix and semi-permeable membrane coating. Poloxamer 407 and sodium bicarbonate were used to prepare the core matrix. Polyvinly acetate dispersion (Kollicoat $SR30D^{(R)}$) and polyvinyl alcohol-polyethylene glycol copolymer ((Kollicoat $IR^{(R)}$)) were employed to form the semi-permeable membrane. The GR tablets significantly expanded up to fivefold in simulated gastrointestinal fluids with no apparent damage of the coating membrane over 12 hours. Also, the swelling rate was controllable with the amount of sodium bicarbonate. The drug release was observed to be substantially sustained based on coating level. The release rate of gabapentin from the GR tablet was gradually slowed down as the coasting amount was increased. The gabapentin GR tablet with 8% coating level showed a pseudo-zero order release kinetics over 12 hours. These results suggest that this swellable GR tablet system having semi-permeable membrane coating can be applicable for hydrophilic drug substances like gabapentin.

• 한국염색가공학회지
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• 제26권1호
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• pp.13-21
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• 2014

The object of this research is to perform the basic research for the development of selectively permeable membrane fabrics which is suitable for korean military in sense of embattlement. As a key factor of selectively permeable membrane fabrics which is suitable for korean military, this study selected the best PVA thickness and membrane selection for DMMP protection, pre-treatment method for conformational stability of face fabric and water/oil repellent process condition. Especially as the PVA coating thickness of the fabrics increase, peneration of DMMP decrease including water vapor permeation is lower. This study shows how physical features and permeability of chemical agents can be influenced by pre-treatment methods, the selection of selectively permeable membrane, the thickness of PVA etc. Results showed that outer shell / PVA / e-PTFE materials possessed performance with superior water vapor permeation (Over $3,000g/m^2/day$) and protective capability against DMMP vapor ($0.6{\mu}g/cm^2{\cdot}16hr$).

• 한국해양공학회지
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• 제22권3호
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• pp.18-23
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• 2008

This study investigated interactions between the internal-external wave field of a permeable coastal structure consisting of rubble. The study examined the application criteria of an existing numerical model (CADMAS-SURF V.4.0) and proposed a modified method to provide reasonable results. In particular, the study focused on and emphasized the water surface profiles in front of a structure, wave run-up/run-down on a slope, and internal water level fluctuations due to the drag coefficient and porosity of a rubble mound structure. In conclusion, the result show that when the vertical fluctuations of the internal water levels in permeable coastal structures exhibited high-quality representation. Sane responses can be seen for wave run-up/run-down characteristics on its slopes.

• 한국지반공학회논문집
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• 제18권5호
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• pp.143-157
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• 2002

주물사의 일반적인 지하수 오염물질인 TCE에 대한 반응성을 조사하기 위해 batch와 column실험을 하였다. 본 실험에서 얻어진 주물사의 반응성은 실제 반응벽체에 쓰여지는 철에 비해 높거나 비슷한 결과를 나타내었다. 또한, 주물사에 포함된 클레이와 TOC에 의해 TCE의 이동이 급격히 감소하는 것을 관찰하였다. 따라서, 실제 현장 상황에서는 토양미생물에 의한 분해에 의해 계산된 값보다 훨씬 낮은 농도의 TCE가 검출되리라 예상된다. 실제 현장 반응벽체 설계에 있어서 1 m두께의 벽체가 설치되기 위해서는 주물사에 포함된 철의 함량이 1%이상이면 안전측으로 벽체설계가 가능하다고 볼 수 있다.