• Journal of Soil and Groundwater Environment
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• v.14 no.4
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• pp.10-14
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• 2009

Objective of this study was to examine the effects of grouts and temperature change on microorganisms in geothermal heat pump. Groundwater samples were obtained from wells in the heat pump system during installation (Oriental medicine hospital) and in the heat pump system under operation (Business incubation center). Grouts are the volclay sodium bentonite. Real-time PCR was used to evaluate total bacterial number and 16S rDNA. The results showed that total bacterial number of groundwater in the heat pump operation was greater than that of non-operation case, which indicates a temperature effect on the bacterial culture. In addition, high concentration of grout showed an elevated bacteria number. In the mean time, a long-term field monitoring is essentially required to confirm the effects of the grouts and the temperature changes.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.195-203
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• 1986

This study was conducted to investigate the characteristics of surface charge of major clay minerals in Korea. The charge characteristics of clay minerals were studied by measuring the retention of $NH^+_4$, $Ca^{2+}$ and $Cl^-$ as a function of ionic strength. The dominant clay minerals of Zeolite, Bentonite and Kaolin were oriented as Clinoptilolite+Mordenite, Montmorillonite and Halloysite, respectively. At the same ionic strength, Montmorillonite and Halloysite adsorbed some more $Ca^{2+}$ than $NH^+_4$, whereas Zeolite adsorbed more $NH^+_4$ than $Ca^{2+}$. All the three minerals adsorbed more ions with higher ionic strength and the C.F.C was larger in the order of Halloysite < Montmorillonite < Zeolite. Since the total surface area by EGME rentention was shown to be in the order of Halloysite < Zeolite < Montmorillonite, therefore, the charge density was calculated to be in the order of Montmorillonite < Halloysite < Zeolite.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.37-42
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• 2006

This paper is concerned with experimental investigation of steering performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of 0.9 m(L)x0.75 m(B)x0.4 m(H) and weight of 167 kg was constructed with a pair of driving chain links, driven by two AC-servo motors. The tracks were configured with detachable grousers with variable span. A deep seabed was simulated by means of a bentonite-water mixture in a soil bin of 6.0 m(L)x3.7 m(B)x0.7 m(H). The turning radii of vehicle and driving torques of motors were measured with respect to experiment variables: steering ratio, driving speed, grouser chevron angle, grouser span, and grouser height. L8 orthogonal table is adopted for DOE (Design of experiment). The effects of experiment variables on steering performance are evaluated.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.165-170
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• 1987

This study was undertaken to elucidate the behavior of herbicide bensulfuron-methyl[methyl-2-[[[[[(4,6-dimethoxy pyrimidine-2yl)amino]carbonyl]amino]sulfonyl]methyl]benzoate]in soils. Adsorption of the herbicide in soils was mainly correlated with content of organic matter and clay, and canon exchange capacity. Adsorption distribution coefficient(Kd value) in clay loam soil was greater than those in loam and sandy loam soils. The Kd value decreased in the order of zeolite, bentonite, halloysite and laziolite clay minerals. Bensulfuron-methyl moved to 3cm deep in clay loam soil and 4cm deep in sandy loam and herbicide treated layer was 0 to 2cm profile in the two soils. The decomposition rate of bensulfuron methyl varied with the soil properties. The rate was slower in sterilized soil than in nonsterilized. Addition of organic matters to the soils accelerated the decomposotion. The degradation was more rapid in 30$^{\circ}C$ soil temperature than in 20$^{\circ}C$.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.71-80
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• 2011

In period of rapid economic development, as doing river conservation work by using harmful materials environmental pollution has adversely effected humans, animals and plants frequently. For recovery of environmental pollution it needs a lot of time and cost. Therefore, in this study, in order to take an environment-friendly method which is also economical and durable both results of the laboratory model test and field test were compared and analyzed. According to the results of the laboratory model test, those methods such as concrete paving, asphalt paving, bentonite mat, stabilized soil method and mixed soil method have small amount of seepage, but on the other hand compaction soil, grassland and permeable materials have considerable amount of seepage. The results of field test show a similar tendency with laboratory test and have been satisfied to assess standard of domestic water permeability below $1.0{\times}10^{-7}cm/sec$ and unconfined compressive strength is also than 1.0MPa so it has been satisfied about standard. In conclusion, as compaction rate increased, as unconfined compression strength increased and coefficient of permeability decreased.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.605-612
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• 2003

In this study, the performance of the cut-off wall with the specific functional adsorption layers(containing SAC), which are formed in order to block harmful materials such as heavy metal ions contained in leachate (or outflow water) from either waste landfills or exhausted mines, was Investigated by determining experimental data such as hydraulic conductivities, unconfined compression strengths, adsorption capacities. The performance was compare to those of the present cut-off wall materials such as clay, bentonite-mixed soil, and soil-cement.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.431-438
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• 1999

Vertical congressive and horizontal pile load tests were performed to a instrumented large diameter (D : 1,000 mm) drilled shaft. A drilled shaft was penetrated into the weathered soil and weathered rock. PMT was done for evaluation of properties for these strata. It was expected to be difficult to get undisturbed samples of weathered soils and rocks. Thus. PMT was done at the several selected depths. In those strata, to prevent the test bore hole from collapsing, bentonite slurry was used for making the test bore hole. In this study. soil properties was evaluated by means of PMT results and estimating method (direct method, the Memard method) of vertical pile capacity and horizontal pile behaviors were summarized. Also, vertical and horizontal pile capacity were calculated using PMT and pile load test results.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.7-16
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• 1990

The sorption of radioactive cobalt and ruthenium on alumina, silica gel, zeolite 3A, kaolin and Na-bentonite has been studied as a function of pH. nuclide concentration and ionic strength. Retardation factor for cobalt and ruthenium on soil minerals was determined through porosity measurement. Hydrolysed species, cobalt and ruthenium interact with solid surfaces by physical adsorption processes. Freundlich sorption isotherms for cobalt and ruthenium are effectively linear. The sorption decreases with increasing ionic strength for cobalt and ruthenium. The effect of increasing porosity on the retardation factor countered the effect of a significant increase in the distribution coefficient.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.127-135
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• 1978

For improvement and new design of tillage equipments, indoor test is very useful and more desirable than outdoor because the experiment of outdoor is very difficult and its cost is expensive. This study was carried out to determine the physical properties of artificial soil suitable for the indoor test with the soil bin manufactured at the workshop of the Dept. of Agricultural Machinery Engineering. The artificial soil being studied was made with very similarity to the natural soil of the experimental plots of Chungnam National University, and it consist of 39.35 percent, by weight of bentonite and 48.10 percent of sand with 12.55 percent of SAE 10W oil. The results are summarized as follows: 1. Bulk density increased with increasing number of rolling, and its relationship could be expressed. $y=1.073200+0.070780x-0.002263x^2$ where, y=bulk density ($g/cm^3$), x=number of rolling. These results could be explained that the effect of rolling velocity on the bulk density was not singnificant in the range of 4.5~10.4 em/sec. 2. The absolute soil hardness depended directly upon number of rolling, and their relationship could be expressed by the equation. $y=37.74(0.64 +0.17x-0.0054x^2)/(3.36-0.17x-0.0054x^2)^3$. where, y=absolute soil hardness($kg/cm^3$), x=number of rolling. 3. Relationship between the bulk density and absolute soil hardness could be expressed by the equation; $y=37.74(2.46x-2.02)/(6.02-2.46x)^3$. where, y=absolute soil hardness, x=bulk density. 4. The cohesion and the angle of internal friction of artificial soil were increased with increasing its bulk density. According to the cohesion and angle of internal friction, at the range of 1.60~1.75 ($g/cm^3$) of bulk density, this artificial soil was similar with sandy loam of 29.5% moisture content of natural soil. 5. Sliding-fricfion coefficient of steel plate on the artificial soil was 0.3~0.4 and rubber plate on it is 0.64~0.72. Those values were very similar with those of natural soil being studies by many others.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.250-253
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• 2003

This paper concerns about an experimental investigation about steering performance of tracked vehicle on extremely soft soil based on DOE(Design Of Experiment) using L8 orthogonal Array. A tracked vehicle model with principal dimensions of $0.9m{\times}0.8m{\times}0.4m$ and weight 167kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers, the span of which can be varied. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of $6.0m{\times}3.7m{\times}0.7m$. Turning radii of vehicle and torques of motors were measured with respect to experimental variables; steering ratio, driving speed, grouser chevron angle, grouser span, grouser height. The effects of experiment variables on steering performance are evaluated.