Pilot-scale field model tests for detecting landfill leachate intrusion into the subsurface using a grid-net electrical conductivity measurement system     

Myoung?Hak?Oh  Ju?Hyung?Lee  Gil?Lim?Yoon  Junboum?ParkEmail author 《Environmental Geology》2003,45(2):181-189

The grid-net electrical conductivity measurement system for detecting exact locations of landfill leachate intrusion in the subsurface was developed in this study. Laboratory and pilot-scale field model tests were performed to evaluate the direct application of a grid-net electrical conductivity measurement system for the detection of landfill leachate. A significant increase in electrical conductivity of soil was observed by adding landfill leachate. This can be explained as an increase in electrical conductivity of pore fluid due to an increase in leachate constituents as charge carriers. In pilot-scale field model tests, leachate intrusion locations were accurately identified at the initial stage of landfill leachate release by the grid-net electrical conductivity measurement system. The electrical conductivity of the subsurface before leachate injection lay within a small range of 24.8–43.0 S/cm. The electrical conductivity values in detected points were approximately ten times more than the conductivity values of the subsurface without landfill leachate intrusion. The results in this study indicate that the grid-net electrical conductivity measurement method has a possible application for detecting locations of landfill leachate intrusion into the subsurface at the initial stage, and thus has great potential in monitoring leachate leakage at waste landfills.  相似文献   

Evaluation of the seismic performance of a three‐story ordinary moment‐resisting concrete frame     

Sang Whan Han  Oh‐Sung Kwon  Li‐Hyung Lee 《地震工程与结构动力学》2004,33(6):669-685

This study focuses on the seismic performance of Ordinary Moment‐Resisting Concrete Frames (OMRCF) designed only for gravity loads. For this purpose, a 3‐story OMRCF was designed in compliance with the minimum design requirements in the American Concrete Institute Building Code ACI 318 (1999). This model frame was a regular structure with flexure‐dominated response. A 1/3‐scale 3‐story model was constructed and tested under quasi‐static reversed cyclic lateral loading. The overall behavior of the OMRCF was quite stable without abrupt strength degradation. The measured base shear strength was larger than the design base shear force for seismic zones 1, 2A and 2B calculated using UBC 1997. Moreover, this study used the capacity spectrum method to evaluate the seismic performance of the frame. The capacity curve was obtained from the experimental results for the specimen and the demand curve was established using the earthquake ground motions recorded at various stations with different soil conditions. Evaluation of the test results shows that the 3‐story OMRCF can resist design seismic loads of zones 1, 2A, 2B, 3 and 4 with soil types S_A and S_B . For soil type S_C , the specimen was satisfactory in seismic zones 1, 2A, 2B and 3. For soil type S_D , the OMRCF was only satisfactory for seismic zones 1 and 2A. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Fusion of multispectral and panchromatic Satellite images using the curvelet transform   总被引：18，自引：0，他引：18  

Myungjin Choi Rae Young Kim Myeong-Ryong Nam Hong Oh Kim 《Geoscience and Remote Sensing Letters, IEEE》2005,2(2):136-140

A useful technique in various applications of remote sensing involves the fusion of different types of satellite images, namely multispectral (MS) satellite images with a high spectral and low spatial resolution and panchromatic (Pan) satellite image with a low spectral and high spatial resolution. Recent studies show that wavelet-based image fusion provides high-quality spectral content in fused images. However, the results of most wavelet-based methods of image fusion have a spatial resolution that is less than that obtained via the Brovey, intensity-hue-saturation, and principal components analysis methods of image fusion. We introduce an improved method of image fusion which is based on the amelioration de la resolution spatiale par injection de structures (ARSIS) concept using the curvelet transform, because the curvelet transform represents edges better than wavelets. Because edges are fundamental in image representation, enhancing the edges is an effective means of enhancing spatial resolution. Curvelet-based image fusion has been used to merge a Landsat Enhanced Thematic Mapper Plus Pan and MS image. The proposed method simultaneously provides richer information in the spatial and spectral domains.  相似文献   

Genetic Implications of Two Different Ultramafic Rocks from Hongseong Area in the Southwestern Gyeonggi Massif, South Korea     

Jieun Seo  Seon Gyu Choi  Chang Whan Oh  Sung Won Kim  Suck Hwan Song 《Gondwana Research》2005,8(4):539-552

Two distinct ultramafic bodies occur in Baekdong and Bibong in the Hongseong area within Gyeonggi massif of South Korea. The Hongseong area is now extensively documented as an extension of the Dabie-Sulu collision belt in China. The Baekdong ultramafic body has a NWW elongation direction. This elongation trend is similar to the general trend of the Dabie-Sulu collision belt. The Bibong ultramafic body is elongated in a NNE direction and runs parallel to the direction of the main fault in the study area. The Baekdong ultramafic bodies show porphyroclastic and mylonitic textures while those at Bibong exhibit a mosaic texture. Both were grouped into peridotite and serpentinite based on their modal abundance of serpentine. In the olivine (Fo) vs. spinel [Cr# = Cr/ (Cr+Al)] diagram, both ultramafic rocks fall with in olivine spinel mantle array. The compositions of olivine, orthopyroxene and spinel indicate that the Baekdong ultramafic rock formed in deeper parts of the upper-mantle under passive margin tectonic setting. The SREE content of Baekdong ultramafic rock vary from 0.19 to 5.7, exhibits a flat REE pattern in the chondrite-normalized diagram, and underwent 5% partial melting. Conversely, large variation in SREE (0.5 21.53) was observed for Bibong ultramafic rocks with an enrichment of LREE with a negative slope and underwent 17 24% partial melting. The Baekdong ultramafic rocks experienced three stages of metamorphism after a high pressure residual mantle stage. The first stage of metamorphism occurred under the eclogite-granulite transitional facies (1123 911°C, >16.3 kb) the second under the granulite facies (825 740°C, 16.3 11.8 kb) and the third is the retrogressive metamorphism under amphibolite facies (782 718°C, 8.2 8.7 kb) metamorphism. The Baekdong ultramafic rocks had undergone high-P/T metamorphism during subduction of the South China Block, and experienced a fast isothermal uplift, and finally cooled down isobarically. Evidences for metamorphism were not identified in Bibong ultramafic rocks. Hence, the Baekdong ultramafic rocks with in the Hongseong area may indicate a link on the Korean counterpart of Dabie-Sulu collision belt between North and South China Blocks.  相似文献   

Sr, Nd and Pb Isotopic Systematics of the Cenozoic Basalts of the Korean Peninsula and Their Implications for the Permo-Triassic Continental Collision Boundary     

Kye-Hun Park  Jun-Beom Park  Chang-Sik Cheong  Chang Whan Oh 《Gondwana Research》2005,8(4):529-538

Sr, Nd and Pb isotopic compositions of the Cenozoic basalts were analyzed from Baengnyeongdo Island, Jeongok, Ganseong, and Jejudo Island of Korea. They reveal relatively enriched Sr and Nd isotopic compositions (⁸⁷Sr/⁸⁶Sr = 0.703300.70555, ¹⁴³Nd/¹⁴⁴Nd = 0.512980.51256) compared with MORB.²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb values of all the analyzed Korean basalts lie above the Northern Hemisphere Reference Line (NHRL) defined by Hart (1984). Pb isotopic compositions of basalts from Jejudo Islands (²⁰⁶Pb/²⁰⁴Pb = 18.6119.12, ²⁰⁷Pb/²⁰⁴Pb = 15.5415.69, ²⁰⁸Pb/²⁰⁴Pb = 38.9839.72) are significantly more radiogenic than the rest (²⁰⁶Pb/²⁰⁴Pb = 17.7218.03, ²⁰⁷Pb/²⁰⁴Pb = 15.4415.58, ²⁰⁸Pb/²⁰⁴Pb = 37.7738.64). The Cenozoic Korean basalts thus can be divided into two groups based on their Sr, Nd and Pb isotopic compositions. The north group reveals mixing between DMM and EM1 while the south group displays DMM-EM2 mixing. Such a distribution is the same as Chinese Cenozoic basalts and it can be interpreted that the subcontinental lithospheric mantle under Korea represents simple lateral continuation of the South and North China Blocks. We suggest that Korean continental collision zone cross the Korean Peninsula through the region between the north and south basalt groups of Korea.  相似文献   

Genetic Environment of the Intrusion-related Yuryang Au-Te Deposit in the Cheonan Metallogenic Province, Korea     

Sang Joon Pak    Seon-Gyu Choi    Chang-Whan Oh  Chul-Ho  Heo  Sang-Hoon Choi  Sung-Won Kim 《Resource Geology》2006,56(2):117-132

Abstract. The Yuryang gold deposit, comprising a Te‐bearing Au‐Ag vein mineralization, is located in the Cheonan area of the Republic of Korea. The deposit is hosted in Precambrian gneiss and closely related to pegmatite. The mineralized veins display massive quartz textures, with weak alteration adjacent to the veins. The ore mineralization is simple, with a low Ag/Au ratio of 1.5:1, due to the paucity of Ag‐phases. Ore mineralization took place in two different mineral assemblages with paragenetic time; early Fe‐sulfide mineralization and late Fe‐sulfide and Au‐Te mineralization. The early Fe‐sulfide mineralization (pyrite + sphalerite) occurred typically along the vein margins, and the subsequent Au‐Te mineralization is characterized by fracture fillings of galena, sphalerite, pyrrhotite, Te‐bearing minerals (petzite, altaite, hessite and Bi‐Te mineral) and electrum. Fluid inclusions characteristically contain CO₂ and can be classified into four types (Ia, Ib, IIa and IIb) according to the phase behavior. The pressure corrected temperatures (≥500d?C) indicate that the deposit was formed at a distinctively high temperature from fluids with moderate to low salinity (<12 wt% equiv. NaCl) and CH₄ (1?22 mole %). The sphalerite geo‐barometry yield an estimated pressure about 3.5 ?2.1 kbar. The dominant ore‐deposition mechanisms were CO₂ effervescence and concomitant H₂S volatilization, which triggered sulfidation and gold mineralization. The measured and calculated isotopic compositions of fluids (δ¹⁸O_H2^O = 10.3 to 12.4 %o; δD_H2^O = ‐52 to ‐77 %o) may indicate that the gold deposition originated from S‐type magmatic waters. The physicochemical conditions observed in the Yuryang gold deposit indicate that the Jurassic gold deposits in the Cheonan area, including the Yuryang gold deposit are compatible with deposition of the intrusion‐related Au‐Te veins from deeply sourced fluids generated by the late Jurassic Daebo magmatism.  相似文献   

A study on the preparation of fine and low soda alumina     

Yi Yong Park  Suong Oh Lee  Tam Tran  Seong Jun Kim  Myong Jun Kim   《International Journal of Mineral Processing》2006,80(2-4):126-132

A simple process to produce fine and low soda α-alumina (α-Al₂O₃) from a commercial grade aluminium trihydroxide (gibbsite, Al(OH)₃) produced by KC Corporation Ltd was developed. There are two options for this process with the first one producing low soda α-alumina (< 0.05% Na₂O) having a mean particle size of 50 μm. The second option yields a fine product with a mean size of less than 10 μm. In the first option, a plant aluminium trihydroxide containing 0.20% Na₂O was first fluidized with nitrogen at 400–600 °C to yield an amorphous activated alumina. This intermediate product was then treated with acetic or oxalic acid, washed with water and heated to 1200 °C to form calcined α-alumina, having a Na₂O content of less than 0.05%. A 20 min leaching using 0.2 M acetic or oxalic acid could yield an alumina product containing 0.04% Na₂O. In the second option, a new technique for the preparation of fine and low soda α-alumina was evaluated using an attrition mill working also as a leaching vessel at 80 °C. Fine (< 10 μm in mean particle size) and low soda (< 0.04% Na₂O) alumina was produced by a 20 min leaching step with 0.2 M acetic acid and concurrent attrition milling.  相似文献   

Eastern Asian hydrometeorology simulation using the Regional Climate System Model     

Jinwon Kim  Norman L. Miller  Jai-Ho Oh  Jun-Seok Chung  Deukkyun Rha   《Global and Planetary Change》1998,19(1-4)

We present the hydrometeorology of eastern Asia during April 1995 simulated by the Regional Climate System Model. The amount and location of simulated monthly precipitation agrees well with observations. Soil water content variation was closely correlated with precipitation. Land-surface evaporation and the surface energy budget were strongly controlled by soil moisture content. A sensitivity test with reduced initial soil moisture content suggested that near-surface soil moisture spins up quickly after heavy precipitation events. However, variations in the initial soil moisture field may alter details of the simulated precipitation which can introduce further complexity in climate simulations.  相似文献   

Geostatistical integration of MT and borehole data for RMR evaluation     

Seokhoon Oh  Hojoon Chung  Duk Kee Lee 《Environmental Geology》2004,46(8):1070-1078

The geostatistical approach was applied to integrate MT (Magneto-telluric) resistivity data and borehole information for the spatial RMR (Rock Mass Rating) evaluation. Generally, resistivity of the subsurface is believed to be positively related to the RMR, thus the resistivity and borehole RMR information was combined in a geostatistical approach. To relate the two different sets of data, the MT resistivity data were used as secondary information and the RMR mean values were estimated at unsampled points by identification of the resistivity to the borehole data. Two types of approach are performed for the estimation of RMR mean values. Then the residuals of the RMR values around the borehole sites are geostatistically modeled to infer the spatial structure of difference between real RMR values and estimated mean values. Finally, this geostatistical estimation is added to the previous means. The result applied to a real situation shows prominent improvements to reflect the subsurface structure and spatial resolution of RMR information.  相似文献   

Effect of boundary element details on the seismic deformation capacity of structural walls     

Young‐Hun Oh  Sang Whan Han  Li‐Hyung Lee 《地震工程与结构动力学》2002,31(8):1583-1602

The objective of this study is to investigate the effect of boundary element details of structural walls on their deformation capacities. Structural walls considered in this study have different sectional shapes and/or transverse reinforcement content at the boundaries of the walls (called boundary element details hereafter). Four full‐scale wall specimens (3000mm (h_w)×1500mm (l_w)×200mm (T)) were fabricated and tested. Three specimens are rectangular in section and the other specimen has a barbell‐shaped cross‐section (a wall with boundary columns). The rectangular wall specimens are reinforced according to the common practice used for reinforced concrete residence buildings in Korea and Chile. In this study, the primary variable for these rectangular specimens is the content of transverse reinforcement to confine the boundary elements of a wall. The barbell‐shaped specimen was designed in compliance with ACI 318‐95. The response of the barbell‐shaped specimen is compared with those of other rectangular specimens. The effective aspect ratio of the specimens is set to two in this study. Based on the experimental results, it is found that the deformation capacities of walls, which are represented by displacement ductility, drift ratio and energy dissipation capacities, are affected by the boundary element details. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献