• Journal of the Mineralogical Society of Korea
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• v.26 no.3
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• pp.189-196
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• 2013

In this study, we tried to define the origin of fine-grained sediments in Southwestern Cheju Island Mud (SWCIM) using principal component analysis. We used relative clay mineral compositions using 138 marine surface sediments, 4 Huanghe sediments and 3 Changjiang river sediments by the semi-quantitative X-ray diffraction analysis. We made bioplot diagram using R program with principal component 1 and component 2 because they might contain more than 90% of all data. Although the distribution pattern of each clay minerals in SWCIM is so intricate, smectite and kaolinite contents are high in the west region, but illite and chlorite contents are rich in the east region. In the biplot, the east region of SWCIM distribute around Changjiang river, whereas west region of SWCIM disperse around Huanghe. Our results might reveal that west region of SWCIM is mainly originated by Huanghe, but east region of SWCIM by Changjiang River.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.501-505
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• 2017

Due to the rapid urbanization and increased population, there is an increase in airtight nature of buildings which causes serious indoor air pollution. Among several indoor air pollutants, volatile organic compounds (VOCs) emitted from paint are of major concern. Therefore, there is an urge for the development of environmental friendly paint products. In this wok, a natural wall paint (NWP) was prepared by utilizing a natural clay material "sericite" as a main component. A small chamber test was carried out to identify the toxic substances release from NWP and the results were compared with two eco-friendly commercial paints. The total VOCs were detected in trace level inside the test chamber and their concentrations were below the recommended indoor air quality standards. Toluene was not detected for NWP, whereas formaldehyde was observed in trace level. The toxicity index results were compared with two commercial paints and found that NWP exhibited less harmful gas emission. Based on certification rating of building materials, NWP can be classified as the first grade of building materials. Due to the above advantages, the use of sericite as a major component in NWP will be a useful technique to maintain the indoor air quality.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.227-232
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• 2017

Subsea pipelines are one of the most important structures used to transport fluids such as oil and natural gas in offshore environments. The uplift behavior of the pipeline caused by earthquakes and buoyancy can result in a pipeline failure. The objective of this study is to examine the peak uplift resistance through parametric studies with numerical modeling by PLAXIS 3D Tunnel. The effects of the embedment ratio and pipe diameter were first examined for uplift resistance in sand and soft clay conditions. Then the length of geogrid layers and the number of geogrid layers were examined in terms of ability to resist uplift behavior.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.281-281
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• 2006

In this study, the polyurethane which has versatile applications has been reinforced with the natural clay, hectorite. The hectorite has better properties than montmorillonite. There are studies on polyurethane and montmorillonite but polyurethane and hectorite composite is published first time. Polyurethane is industrial polyurethane which makes the study to be applicable to the industry. Exfoliated structure has been obtained without using organic modifiers due to the hydrophilic nature of the polymer matrix and the mineral clay. Mechanical properties have been improved as well.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.91-97
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• 2001

Case records comprising the results of down-hole seismic surveys collected at nine sites worldwide, together with comparative results of laboratory bender element tests on reconstituted clay samples, were examined in an attempt to quantify the shear modulus of normally consolidated clays at very small strain of the order of 0.001%. The shear modulus G$_{max}$ under the current state of stresses is given in a formula which includes a newly proposed void ratio function. An empirical expression incorporating the new void ratio function is also proposed for practical use in estimating G$_{max}$ profiles with depth in natural soil deposits from routinely available borehole data.ata.

• Journal of Industrial Technology
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• v.34
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• pp.53-59
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• 2014

The single regression method was used to analyze the correlationship between the compression index with mechanical properties for reclaimed marine clays in the southern coast of Korea. As results of performing regression analysis for 200 samples about reclaimed marine clays in the southern coast of Korea, linear regression lines between compression index and natural water content, void ratio in situ, and liquid limit respectively wer obtained. The changed properties of soil due to disturbance during dredging and reclaiming could be investigated by comparing with the existing empirical correlation equations for the original ground where dredging was performed. These regression equations might be rationally used in the preliminary evaluation of settlement of dredged and reclaimed marine clayey ground in the southern coast of Korea.

• Journal of Industrial Technology
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• v.35
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• pp.81-88
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• 2015

The single regression method was used to analyze the correlationship between the compression index with mechanical properties for reclaimed marine clays in the Gyeonggi coast of Korea. As results of performing regression analysis for 62 samples about reclaimed marine clays in the Gyeonggi coast of Korea, linear regression lines between compression index and natural water content, void ratio in situ, and liquid limit respectively were obtained. The changed properties of reclaimed soil due to disturbance during dredging and reclaiming could be investigated by comparing with the existing empirical correlation equations for the original ground where dredging was performed.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.06c
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• pp.1.2-22
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• 1997

Anisotropic behaviour in soils and soft rocks may be either fabric of stress related ultra in practice is invariably a combination of both. Theoretical studies in the paper include tile iMluence oil untrained strength of assuming both the critical state and Mo21r-Coulomb concepts to hold, and the influence of elastic anisotropy oil predicted undrained effective stress paths. The predictions stemming from these theoretical concepts are examined in the light of evidence from triaxial compression and extension tests oil laboratory prepared, compacted and natural clays and from triaxial compression tests on clay shales. The experimental studies also show the Buence of sample orientation on untrained snear strength, as wen as the iIBluence of anisotropy old the effective stress angle cishearing resistance and of stress patn on measured stiffness.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.51-59
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• 2008

In this study, cyclic shear characterics of sand-clay mixtures were analyzed. In order to perform cyclic triaxial tests on sand clay mixtures, natural clays with activity and silica sand were mixed variously to reproduce soils with wide range of grain size compositions. Test specimens with various fines contents were prepared by the moisture compaction and pre-consolidation methods, while paying attention to the void ratio expressed in terms of the sand structure and clay structures, and undrained cyclic shear tests were performed. In the test results, cyclic shear strength decreased with increasing of sand granular void ratio below 20% of fine contents. When the granular void ratio of the test specimen exceeded the maximum void ratio of the silica sand, the clay matrix dominated the soil structure, and soil structures were not influenced by compaction energy. It was observed that, the matrix structure of the coarse particles has great effect on the undrained cyclic shear strength characteristics for sand-clay mixtures, and therefore, it is more appropriate to pay more attention to the density of the sand structure, rather than to the fines content.

• Journal of Environmental Science International
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• v.10 no.1
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• pp.65-71
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• 2001

HRP(high rate pond) which had kept the manufactured clay of 3cm-thickness as benthic clay in reactor and the 6 flat-blade turbine as impeller for agitation was named HRASP(high rate algae stabilization pond). And the experiment for treatment of artificial synthesis wastewater containing COD :300mg/$\ell$, NH$_3$-N : 300mg/$\ell$, T-P : 9mg/$\ell$ as nutrients was been performed successfully. This reactor was been operated under conditions : 24hrs.-irradiation and water temperature, $25^{\circ}C$ and pH 7 and agitation velocity, 15, 30, 45rpm and the effect of agitation velocity on algal bioaccumulation of nutrients was been studied with view point of fluid dynamics. The next followings could be obtained as results. 1. The agitation with a turbine impeller blade in HRASP makes clay particle indicate superior suspension effect by means of forming of excellent curl/shear flow in reactor. 2. The excessive suspension of clay particle which is created at 45rpm as rotation velocity of impeller blade of turbine disturbs the light penetration and algal photosynthesis reaction. 3. Efficiencies for removal of nutrients come out as COD : 93.9%~94.3%, ($NH_3-N + NO_3-N$) : 81.9%~99.0%, T-P : 46.8%~53.6%. 4. Kuo values of $K_1$for algal growth come out seperately as 15rpm : $1.876{\times}10^{-2}, 30rpm : 4.618{\times}10^{-3}$. 5. Kuo values of $K_2$for removal of N, P come out seperately as 15rpm : $8.403{\times}10^{-1}$ and $1.397{\times}10^{-1}$, 30rpm : $4.823{\times}10^{-1} and 2.052{\times}10^{-1}$. 6. It can be guessed easily that the excessive agitation can inhibit the algal and bacterial symbiotic reaction if it is considered that micro organism\` sense to preservation of life is relied on natural function of metabolism. Therefore the studies for this matter should be followed continuously.