• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.234-246
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• 2007

The role of macropore in the hydrological processes is important at the hillslope scale. Developments and distribution of macropores have not been investigated in conjunction with the characteristics of the hillslope such as topography, soil property, and soil moisture. In this study, macropore properties, such as macropore flow and saturation hydraulic conductivity were measured at a hillslope located in Gwangneung Research Forest, Pochun-gun, Gyeonggi-do, South Korea. An intensive field survey provided a refined Digital Elevation Model (DEM) for surface and subsurface topography. Spatial distributions of upslope area and topographic index were obtained through the digital terrain analysis. The total number of monitoring points was 22, and the selected points were distributed along the transect of the digital contour map. Vertical fluxes through macropores were measured using a tension infiltrometer at the depth of 0.1 m from the surface. Spatial and temporal distributions of soil moisture were obtained using an on-line measurement system, TRASE, installed in the study area. Soil moisture for the aforementioned points was measured at 0.1 and 0.3m depths below the surface. The results from tension infiltrometer experiments present that the macropore flows ranged between 21 and 94%, and the measured macroporosities varied from 1.4 to 47%. Macropore flows and macroporosities tended to increase as the measurement location moved to downslope. The ability for water conduction through macropores becomes increasingly developed as the location approaches the outlet of the hillslope.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1517-1521
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• 2009

A variation of pore structure of shotcrete matrix was experimented by Mercury Intrusion Porosimetry, and the relation with compressive strength was also examined. As a result of the Mercury Intrusion Porosimetry(MIP) test, RM-P1 Batch the macropore diameter of the RM-BFS2 and RM-BFS3 Batch than to have a relatively macropore can see a lot of long-term durability performance degradation. Also, K and N Batch the current is applied to the mine if the factors on shotcrete durability performance of the macropore volume of the entire appears to be a long-term durability performance in the fall.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.777-785
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• 1997

This study was conducted to clarify the hydrological characteristics of subsurface flow through a soil matrix and macropores. The research facility was set up in a 20m-1ong trench excavated down to bedrock at the base of a hillslope in the Panola catchment under USGS Georgia district. 13 macropores were found on the trench face and 6 major macropores were monitored. Matrix and macropore flow were measured during 95.5mm rainfall on March, 6 to 7. 1996. Macropore flow had great influence on formation of peak flow because the delivery time to Peak flow of macropore flow were faster about 10hrs than those of matrix flow. Matrix flow continued to recess for 3 days. On the other hand, macropore flow stopped within 12hrs after the event ceased. This means that matrix flow controls the recession part. The spatial variations of matrix and macropore flow between each trough and collector were very large by a wide range of 8,655.3 $\ell$ to 17.8 $\ell$ . The bed rock surface topography relates closer with the spatial variations of the flow than the surface one.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.207.2-207
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• 2002

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.71.1-71.1
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• 2010

고분자 전해질 연료전지(PEMFC) 내의 기체확산층(GDL)은 셀 내의 물 관리에 중요한 역할을 수행한다. 일반적으로 다공성 기제(GDBL) 위에 미세기공층(MPL)을 코팅한 2층 구조의 기체확산층이 사용되는데, 이 미세기공층은 카본파우더와 테프론의 혼합물로 이루어져 있으며 촉매층에서 발생한 물을 셀 밖으로 빠르게 배출하는 역할을 수행한다. 본 연구에서는 다양한 기공분포를 갖는 미세기공층을 제조하여 고분자 전해질 연료전지 성능에 미치는 영향을 분석하였다. 미세기공층 슬러리내에 암모늄염 계열의 기공형성제를 혼합하여 다공성 기제 위에 코팅한 후 다양한 온도조건에서 건조함에 따라 기공분포가 다른 미세기공층을 제조하였다. 이렇게 제조된 미세기공층의 물성은 수은기공도계, FE-SEM, 자체적으로 제조한 기체투과도 측정 장치를 사용하여 측정하였으며, 단위 전지 성능 측정은 두 개의 가습조건(RH100%, RH50%)에서 실시하였다. 기공분포 측정결과 건조온도가 높은 미세기공층은 건조온도가 낮은 미세기공층에 비해 직경이 1,000 - 20,000 nm 인 대공극(macropore)의 수가 많지만, 직경이 100 nm 이하의 미세공 (micropore)의 수가 적은 것을 확인하였다. 전지성능 측정 결과 고가습 조건 (RH100%)에서는 미세공 (micropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 보여고, 저가습 조건 (RH50%)에서는 대공극 (macropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 나타내었다. 이는 물배출에 유리한 미세공 (micropore)의 성질과 원료 기체의 이동에 유리한 대공극(macropore)의 성질에 의한 것으로 판단된다. 따라서 셀 운전 가습조건에 따라 최적화된 기공구조를 갖는 미세기공층을 사용함으로써 셀 운전 성능을 향상 시킬 수 있을 것으로 예상된다.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.295-306
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• 2002

The modified TOPMODEL of two storage systems has been integrated to the generalized assumptions of decreasing hydraulic conductivity to vertical direction. Three different recharge functions were introduced to explore the impact of the macropore flow to vortical direction, the storage at the surface zone and the relative storage deficit of the soil matrix. Combinations of these approaches provide 30 type of the model structure for the hillslope hydrology. Developed models have been applied to several hydrologic events at the Sulmachun watershed. The performance evaluation with the Monte carlo simulation suggests that the exponential function of transmissivity reduction should be appropriate form for the physically -based hydrologic simulation on the Sulmachun watershed. It has been shown that the recharge function of macropore flow contributes to improve the predictability of the generalized version of modified TOPMODEL.

• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.181-184
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• 2013

Highly ordered porous materials having mesopores in the walls of macropores showed improved adsorption dynamics results for VOC molecules, especially bulky molecules. These meso/macroporous mataerials were synthesized by the dual templating method, and mesopore and macropore size were controlled by adjusting the templates for each pore size regime. In the case of adsorption and desorption of small VOC molecules (toluene), although meso/macroporous MCM-41 with smaller mesopore size showed improved results, meso/macroporous SBA-15 with larger mesopore size was not improved regardless of the existence of macropores, since there was no limitation of movement through the larger mesopore. However, the adsorption dynamics of bulky VOC molecules (p-xylene) over meso/macroporous SBA-15 were drastically improved by increasing the macropore size.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.151-156
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• 2010

Porous mullite/alumina composites have been fabricated by a freeze casting technique using TBA-based coal fly ash/alumina slurry. After sintering, unidirectional macropore channels aligned regularly along the TBA ice growth direction were developed; simultaneously, small sized micropores fromed in the outer walls of the pore channels. The physical and mechanical properties (e.g. porosity and compressive strength) of the sintered porous composites were roughly dependant of processing conditions, due to the complexity of the factors affecting them. However, with increasing solid loading and sintering temperature, the compressive strength generally increased and the porosity decreased. After sintering $1500^{\circ}C$ for 2 h, the porous specimen (porosity: 52.1%) showed a maximum compressive strength of 70.0 MPa.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.86-91
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• 2006

Oil spills caused by the accidents have been occurred from house and factory waste, grounded tanker, the rupture of storage tank and oil pipelines, the deterioration of various industrial facilities, etc. Many oil spills result in contamination of shorelines and workplace. Fire and explosion may happen from these spills. There are several technologies used for clean-up application, which include use of oil dispersing agents, absorbents, solidifiers, booms and skimmers by physical, chemical, and biological methods. Methods for oil spill clean-up operation are classified into the absorption type, gel type and self-swelling type. Porous materials with oil absorptive properties are classified into micropore, mesopore, and macropore depending on their pore sizes. Recently, new porous materials with smaller size have been developed, but the selective oil absorption in water-in-oil interface demonstrates the macro pore size. In this study oil absorption effects were evaluated using the organic porous materials with a complex function of gel type and swelling type. Samples were subjected to analysis by FT-IR spectroscopy and were characterized in terms of gel formation and morphologies. Oil sorption capacity, pressure retention force and gel strength were also measured. From these results, the physicochemical reactivity before and after gelation was verified and the industrial applications of clean-up operation were suggested.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.479-485
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• 2008

Porous $TiO_2$ nanostructured particles containing both mesopores and macropores were fabricated by utilizing an aerosol templating method from two kinds of starting materials (colloidal mixture of $TiO_2$ nanoparticles and PS particles, and that of TTIP solution and PS particles). The effects of mixing ratio of PS to $TiO_2$ and reactor temperature on the particle properties were investigated. When $TiO_2$ nanoparticles were used as starting materials, the increase of macropores number was observed by SEM and the specific surface area and total pore volume were increased from $31.6m^2/g$ to $39.1m^2/g$ and $0.068cm^3/g$ to $0.089cm^3/g$, respectively, by increasing the weight mixing ratio of $PS/TiO_2$ from 0.79 to 1.31. When TTIP was used as precursor, the specific surface area and mesopore volume of particles prepared at same condition decreased by 67% and 75%, respectively.