• Journal of the Korean Geotechnical Society
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• v.34 no.3
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• pp.57-65
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• 2018

This study adopts high resolution 3D X-ray CT imaging technique to visualize and evaluate the internal structure of experimentally frozen soils. Temperature and elastic wave velocity are also measured during the freezing process. The X-ray images of frozen specimens reveal that no changes in internal structure are observed for sand specimen, whereas systematic growth pattern of pore ice is observed within clay specimen. The freezing patterns are then quantified by a set of X-ray images with the aid of two-point correlation method by computing characteristic length Lr. The results reveal that characteristic length for pore ice freezing pattern in clay linearly increases with respect to the distance from the cooling source, so that Lr at the bottom layer is 2.5 times greater than the top layer when freezing process is completed. Furthermore, during the freezing process, local temperature differences are not observed in sand, but observed in clay specimen due to its relatively low thermal conductivity.

• Journal of the Mineralogical Society of Korea
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• v.24 no.3
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• pp.205-216
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• 2011

Mineral compositions of 69 southeastern Yellow Sea surface sediments collected at the Korea Ocean Research and Development Institute (KORDI) cruise in 2010, were determined using the quantitative X-ray diffraction analysis. Southeastern Yellow Sea surface sediments are composed of major minerals (quartz 49.1%, plagioclase 13.0% and alkali feldspar 9.3%), clay minerals, calcite, and aragonite. Illite (9.4%) is the most abundant clay mineral, chlorite (4.6%) is the second, and kaolinite (0.8%) is few. Quartz and alkali feldspar contents are high in coarse-grained sediments, whereas amphibole and clay mineral contents are high in fine-grained sediments. Quartz, plagioclase, alkali feldspar, chlorite, and kaolinite contents are higher, and illite content is lower in mud zone 1 corresponding to south margin of Central Yellow Sea Mud than in mud zone 2, a part of Southeastern Yellow Sea Mud. Difference of mineral composition between two mud zone suggests that source of fine sediment may be different in two mud zone and Southeastern Yellow Sea Mud might be largely supplied from the Keum and Youngsan rivers in southern part of the west coast in the Korean Peninsula.

• Journal of Conservation Science
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• v.25 no.3
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• pp.299-316
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• 2009

The Goryeo roof tiles from the Oegol site in Tangjeong, Asan are classified into three groups in color such as gray, red yellow and gray-yellow groups, respectively. While each group of tiles shows characteristic specific gravity, absorption ratio, LOI and vitrification degree, mineral content and distribution, and chemical composition are generally homogeneous among all groups of roof tiles. Also, all roof tiles and soils from the site show similar geochemical behavior of elements and clay-mineralization degree. This indicates that the soil from the site is probable to be a raw material of the roof tiles. Firing temperature of the roof tiles is estimated as 950 to $1,050^{\circ}C$ for the gray group, 800 to $900^{\circ}C$ for the red yellow group, and 900 to $950^{\circ}C$ for the gray-yellow group. In conclusion, roof tiles from the Oegol site is interpreted to be made of local clay without additive minerals, applying various firing conditions and standardized purifying process of raw clay materials.

• The Korean Journal of Quaternary Research
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• v.23 no.1
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• pp.25-37
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• 2009

Geochemical composition and clay minerals of surface and core sediments around off the Jeju Island were analyzed for identification of sediment origins. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. Smectite is highly concentrated (>8%) in the northwest near the South Yellow Sea and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe River. The relatively high abundance of kaolinite are found in northeastern nearshore area and the southwest near Changjiang estuary. It seems to be supplied from Changjiang River and the southwestern Korea rivers. The sediment accumulation rates measured by $^{210}Pb$ geochronrom mowere 0.20 to 0.54cm/mr or 0.15 to $0.42g/cm^2{\cdot}mr^{-1}$ AOJI, with decreasing rates from the west part to the east part, resulting in the supply of fine-grained suspended sediments from the Changjiang and Huanghe Rivers system. The discrimination diagrams clearly show that the sediments around Jeju Island in the northern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from Korean rivers and the Jeju Island.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2003.05a
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• pp.66-66
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• 2003

King George island, Antarctica, is mostly covered by ice sheet and glaciers, but the land area is focally exposed for several thousand years after deglaciation. For a mineralogical study of chemical weathering in the polar environment, glacial debris was sampled at the well-developed patterned ground which was formed by long periglaclal process. As fresh equivalents, recently exposed tills were sampled at the base of ice cliff of outlet glaciers and at the melting margin of ice cap together with fresh bedrock samples. Fresh tills are mostly composed of quartz, plagioclase, chlorite, and illite, but those derived from hydrothermal alteration zone contain smectite and illite-smectite. In bedrocks, chlorite was the major clay minerals in most samples with minor illite near hydrothermal alteration zone and interstratified chlorite-smectite in some samples. Smectite closely associated with eolian volcanic glass was assigned to alteration in their source region. Blocks with rough surface due to chemical disintegration showed weathering rinds of several millimeter thick. Comparision between inner fresh and outer altered zones did not show notable change in clay mineralogy except dissolution of calcite and some plagioclase. Most significant weathering was observed in the biotite flakes, eolian volcanic glass, sulfides, and carbonates in the debris. Biotite flakes derived from granodiorite were altered to hydrobiotite and vermiculite of yellow brown color. Minor epitactic kaolinite and gibbsite were formed in the cleaved flakes of weathered biotite. Pyrite was replaced by iron oxides. Calcite was congruently dissolved. Volcanic glass of basaltic andesite composition showed alteration rim of several micrometer thick or completely dissolved leaving mesh of plagioclase laths. In the alteration rim, Si, Na, Mg, and Ca were depleted, whereas Al, Ti, and Fe were relatively enriched. Mineralization of lichen and moss debris is of much interest. They are rich of A3 and Si roughly in the ratio of 2:1 to 3:1 typical of allophane. In some case, Fe and Ti are enriched in addition to Al and Si. Transmission electron microscopy of the samples rich of volcanic glass showed abundant amorphous aluminosilicates, which are interpreted as allophane. Chemical weathering in the King George Island is dominated by the leaching of primary phyllosilicates, carbonates, eolian volcanic glass, and minor sulfides. Authigenesls of clay minerals is less active. Absence of a positive evidence of significant authigenic smectite formation suggests that its contribution to the clay mineralogy of marine sediments are doubtful even near the maritime Antarctica undergoing a more rapid and intenser chemical weathering under more humid and milder climate.

• Economic and Environmental Geology
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• v.31 no.1
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• pp.69-84
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• 1998

A geochemical study was carried out to define how marine shore sediments are related to their terrestrial source rocks in the region of Taean and Byunsan Peninsula, western Korea. The lithology of the coastal part of the study area is composed of Pre-Cambrian granite gneiss, schist, Jurassic terrestrial sedimentary rocks, and Cretaceous plutonic intrusives. Shore sediments are transported from three drainage tributaries. The sediments consist of quatrz with clay minerals, such as illite, kaolinite, smectite, chlorite. Heavy minerals include hematite, ilmenite, rare amount of zircon and apatite. Compared to those in coastal rocks, amount of heavy minerals in the sediments is considerably low. The low content of heavy minerals is thought to be attributed to the heavy mineral detainment in the river beds and influences of tidal currents which cause heavy minerals to accumulate in specific spots. Chemical composition of the major and trace elements, trace elements, and REE chondrite normalized pattern suggest that shore sediments transported from the corresponding drainage tributary show close mineralogical and geochemical relationships with the source rocks distributed in the Taean and Byunsan Peninsula.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.308-319
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• 2005

Piezo-ceramics are special materials which transform energy between mechanical and electrical forms. Bender-elements are composite materials consisting of thin piezo-ceramics and elastic shims, and are widely used as actuators and transducers in the field of electronics, robotics, autos and mechatronics utilizing the effectiveness of energy transformation capability. In geotechnical engineering, commercial bender-elements are used in laboratory as source and receiver in the measurements of soil stiffness. The elements were built by using various metal shims sandwiched between piezo-ceramics and coating over the composite in the research. A pair of elements were buried in a concrete block and used as source and receiver to measure the stiffness of the concrete. The test results were verified by comparing with the resonant column testing results. In a preliminary stage of the development of an in-situ seismic testing equipment using bender-elements for soft clay materials, shear waves were generated and measured by burying the elements in the barrel of kaolinite and water mixture. The measured shear wave signals were so distinct for the first-arrival pick that applicability of the elements in the field measurements is very promising.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.1
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• pp.87-95
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• 1983

This study was conducted to evaluate the affect of soil conditioners and their application rates on the growth, Yield and quality of Flue-cured tobacco. Soil conditioners for this study were Montmorillonite arid Zeolite as clay mineral source and Rice hull and Sawdust as organic source. Their application rates were 500, 1000, 2000kg/10a. The growth of tobacco plants was promoted, compared with that of Non- treated plot (control) by Zeolite, Montmorillonite and Rice hull application but decreased by Sawdust application. During tobacco growing season soil moisture content, compared with control, was increased by Zeolite and Montmorillonite application but decreased by Rice hull and Sawdust application. In contrast to soil moisture content, soil temperature was higher in the Rice hull and Sawdust plot than in the plot of Zeolite and Montmorillonite. The treatment of Sawdust, compared with control, obviously accelerated the maturity of tobacco, increased reducing Sugar but decreased total alkaloids, nicotine and nitrogen content of cured leaves. The Sawdust Plot decreased the Yield (kg/10a) with significant difference by 1 %level but significantly increased leaf quality (Won/kg) and value (Won/10a) by 1%and 5 %level, respectively. The present application , ate of Nitrogen in Korea (12.5kg/10a) seems to be excessive for Flue-cured tobacco production.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1171-1179
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• 2012

Headwaters initiate material export to downstream environments. A nested headwater study examined the flux of dissolved constituents and water from a perennial stream and four ephemeral/intermittent streams in the Upper Gulf Coastal Plain of Mississippi. Water was collected during storm and baseflow conditions. Multiple linear regression was used to model constituent concentration and calculate flux. Event was the major source of water discharged from the ephemeral and intermittent streams however, baseflow was the major source for water discharged by the perennial stream during events. The perennial stream had an area weighted average yields of 10.1, 0.01, 1.03, 0.65 kg/ha/yr of DON (dissolved organic nitrogen), $NO_3^-$-N, $NH_4^+$-N and $PO_4^{-3}$, respectively while large variabilities existed between the ephemeral and intermittent streams. These findings highlight the importance of headwaters in protecting the low order drainage basins as a key to water quality within perennial streams.

• Journal of environmental and Sanitary engineering
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• v.21 no.3 s.61
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• pp.37-43
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• 2006

Recently, needs for reuse of sludge produced from WTP(water treatment plant) have been increased with shortage of landfill sites and difficulties of the treatment and disposal processes. Therefore, Reusing is becoming an Increasingly popular waste management alternative to divert waste from landfills. In order to research the characteristics of WTP sludges, we used the sludges of C WTP which intake the lake Dae-Cheong and the sludges of S WTP which intake Keum river, The specific surface area of C and S WTP sludges were $0.9986m^2/cc\;and\;1.874m^2/cc$, respectively. The gravity was about $2.0{\sim}2.4$ which are scope of peat or loamy clay. The major minerals of C WTP sludges were kaolinite(48.4%), muscovite(19.5%), and quartz(16.7%). Also, muscovite(31.6%), quartz(30.3%), and kaolinite(17.3%) in S WTP sludges were major minerals.