• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.103-109
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• 2009

Soils originated from limestone, located at the southern part of Kangwon province and Jecheon, Danyang of Chungbuk province are mainly composed of fine texture, and have different properties from soils originated from granite and granite gneiss, especially for water movement. This study was conducted for classification of hydrologic soil group (HSG) of soils originated from limestone by measuring the infiltration rate of surface soils and percolation rate of sub soils. Soils used for the experiment were 6 soils in total : Gwarim, Mosan, Jangseong, Maji, Anmi and Pyongan series. Infiltration and percolation rate were measured by a disc tension infiltrometer and a Guelph permeameter, respectively. Particle size distribution and organic matter content of the soils were analyzed. HSG, which was made by USDA NRCS(National Resources Conservation Service) for hydrology, of Gwarim series with O horizon of accumulated organic matter was classified as type A which show the properties of low runoff potential, rapid infiltration and percolation rate. HSG of Mosan series, which has high gravel content and very rapid permeability, was classified as type B/D because of the impermaeble base rock layer under 50cm from surface. HSG of Jangseong series with shallow soil depth was classified as type C/D owing to the impermaeble base rock layer under 50cm from surface. HSG of Maji series was type B, and HSG of Anmi series used as paddy land was type D because of slow infiltration and percolation rate caused by the disturbance of surface soil by puddling. HSG of Pyeongan series having a sudden change of layer in soil texture was type D because of the slow percolation rate caused a the layer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.3
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• pp.43-51
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• 1986

Triaxial compression tests were performed with control of vertical stress, confined pressure(${\sigma}_H$), and injection velocity by means of impervious soil samples with a different grain size, density and grout density. By measuring pore water pressure at the time of vertical fracturing around the bore-hole, relationships between main factors are described, and the factors are pore water pressure, confined pressure, vertical fracturing injection pressure(${\sigma}$) and the tension strength(${\sigma}_t$). The hydraulic fracturing of soft clay was occurred at the pressure which was less than the pressure obtained by the theory of elasticity. It was found that the above result was the influence of pore water pressure due to injection pressure($U_a$) and pore water pressure due to confined pressure($U_i$). Therefore, the vertical injection pressure at the time of fracturing needs to be changed as follows. $${\sigma}=2{\cdot}{{\sigma}_H}-(U_a+U_i)+{\sigma}_t$$.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.37-45
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• 2010

Surfactant-enhanced ozone sparging (SEOS), an advanced version of SEAS (surfactant-enhance air sparging) was introduced in this study for the first time for removal of non-volatile contaminant from aquifer. The advantages of implementing SEAS, enhanced air saturation and expanded zone of sparging influence, are combined with the oxidative potential of ozone gas. Experiments conducted in this study were tow fold; 1-dimensional column experiments for the changes in the gas saturation and contaminant removal during sparging, and 2-dimensional box model experiment for the changes in the size of zone of influence and contaminant removal. An anionic surfactant (SDBS, sodium dodecylbenzene sulfonate) was used to control surface tension of water. Fluorescein sodium salt was used as a representative of watersoluble contaminants, for its fluorescence which is easy to detect when it disappears due to oxidative degradation. Three different gases (air, high-concentration ozone gas, and low-concentration ozone gas) were used for the sparging of 1-D column experiment, while two gases (air and low-concentration ozone gas) were used for 2-D box model experiment. When SEOS was performed for the column and box model, the air saturation and the zone of influence were improved significantly compared to air sparging without surface tension suppression, resulted in effective removal of the contaminant. Based on the experiments observations conducted in this study, SEOS was found to maintain the advantages of SEAS with further capability of oxidative degradation of non-volatile contaminants.

• Journal of Bio-Environment Control
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• v.7 no.4
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• pp.330-335
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• 1998

To investigate the effect of soil water control on yield and quality of musk melon in plastic film house, irrigation points were treated with -10, -20, -30, -50 and -100 kPa by 10mm dripping each time at fruit developing and ripening stage, respectively. Fresh weight of stem and leaves was not significant among irrigation points, but percentage of dry matter was highest at -100kPa and lowest at -10kPa. Marketable yield was not different among -50kPa, -100kPa, -30kPa and -20kPa and lowest at -10kPa. Sugar content of the flesh fruit at ripening stage was 15.1 $^。/Brix at -50kPa and 14.4 $^。/Brix at -10kPa Therefore, optimum irrigation point at ripening stage of fruit is -50kPa by 10mm dripping each time. time.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.477-486
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• 2023

In the studies on fault dislocation of tunnel, existing literatures are mainly focused on the problems caused by normal and reverse faults, but few on strike-slip faults. The paper aims to research the deformation and failure mechanism of a tunnel under strike-slip faulting based on a model test and test-calibrated numerical simulation. A potential faulting hazard condition is considered for a real water tunnel in central Yunnan, China. Based on the faulting hazard to tunnel, laboratory model tests were conducted with a test apparatus that specially designed for strike-slip faults. Then, to verify the results obtained from the model test, a finite element model was built. By comparison, the numerical results agree with tested ones well. The results indicated that most of the shear deformation and damage would appear within fault fracture zone. The tunnel exhibited a horizontal S-shaped deformation profile under strike-slip faulting. The side walls of the tunnel mainly experience tension and compression strain state, while the roof and floor of the tunnel would be in a shear state. Circular cracks on tunnel near fault fracture zone were more significant owing to shear effects of strike-slip faulting, while the longitudinal cracks occurred at the hanging wall.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1598-1609
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• 2013

Organochlorine pesticide residues continue to remain as a major environmental threat worldwide. Lindane is an organochlorine pesticide widely used as an acaricide in medicine and agriculture. In the present study, a new lindane-degrading yeast strain, Pseudozyma VITJzN01, was identified as a copious producer of glycolipid biosurfactant. The glycolipid structure and type were elucidated by FTIR, NMR spectroscopy, and GC-MS analysis. The surface activity and stability of the glycolipid was analyzed. The glycolipids, characterized as mannosylerythritol lipids (MELs), exhibited excellent surface active properties and the surface tension of water was reduced to 29 mN/m. The glycolipid was stable over a wide range of pH, temperature, and salinity, showing a very low CMC of 25 mg/l. Bio-microemulsion of olive oil-in-water (O/W) was prepared using the purified biosurfactant without addition of any synthetic cosurfactants, for lindane solubilization and enhanced degradation assay in liquid and soil slurry. The O/W bio-microemulsions enhanced the solubility of lindane up to 40-folds. Degradation of lindane (700 mg/l) by VITJzN01 in liquid medium amended with bio-microemulsions was found to be enhanced by 36% in 2 days, compared with degradation in 12 days in the absence of bio-microemulsions. Lindane-spiked soil slurry incubated with bio-microemulsions also showed 20-40% enhanced degradation compared with the treatment with glycolipids or yeast alone. This is the first report on lindane degradation by Pseudozyma sp., and application of bio-microemulsions for enhanced lindane degradation. MEL-stabilized bio-microemulsions can serve as a potential tool for enhanced remediation of diverse lindane-contaminated environments.

• Economic and Environmental Geology
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• v.34 no.4
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• pp.417-422
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• 2001

Sutfactants may be used in remediation of subsoil and aquifer contaminated with hydrophobic compounds. The objectives of this study were to select potentially suitable sUlfactants that solubilize toluene present as a contaminant and to determine the effectiveness of toluene removal from Ottawa sand by the selected surfactants. Material used as the model soil was Ottawa sand and the organic used as model contaminant was toluene. Used experimental methods were separatory funnel experiment and shaker table agitation/centrifugation experiments. Based on the experimental results, the following conclusions were drawn; t) In the surfactant selection, six different surfactants were chosen based on surfactant types, toxicity, and water solubility. These six were focused into two on the basis of HLB and surface tension study, separatory funnel experiment, shaker table and centrifugation experiments. The two most suitable surfactants were Sandopan JA36 (an anionic surfactant), and Pluronic L44 (a non-ionic surfactant). 2) In the shaker table agitation and centrifugation experiments, the highest recovery of the toluene was 96% which was obtained with one surfactant wash plus two water rinses using an anionic surfactant (Sandopan JA36).

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.184-188
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• 1996

The Acinetobacter sp. BE-254 isolated from soil sources produced a bioemulsifier in the medium supplemented with n-hexadecane. This bioemulsifier was purified by the procedures of fractionation (ammonium sulfate and chilled acetone), extraction by hexane, and column chromatography on silica gel 60. The results from various color reactions indicated that the bioemulsifier was a glycolipid. The purified emulsifier was very stable at pHs ranging from 4 to 10 and under heat treatment at $100^{\circ}C$ for 30 min. Emulsification activity was also hardly influenced by pH. The critical micelle concentration (CMC) and surface tension at the point ($\gamma_{cmc}$) of the bioemulsifier were approximately 35 mg/l and 30 mN/m, respectively. The bioemulsifier showed a fairly good emulsification activity and stability in comparison with other commercial emulsifiers in the basic formula composed of emulsifier, oil, and water.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.497-500
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• 2000

A biosurfactant producing bacteria strain, D2D2 was selected from diesel-contaminated soil, and identified as Pseudomonas aeroginosa. A glycolipid produced by P. aeroginosa D2D2 was purified by ethyl acetate extraction and adsorption chromatography. The biosurfactant was Identified as glycolipid which has two types of biosurfactants as a results of TLC analysis. The purified glycolipid biosurfactant reduced the surface tension of water to 27 dyne/cm. In time course studies of growth and rhamnolipid production in a minimal salts medium containing 1.5% glucose and 1.5% olive oil, a maximum rhamnolipid yield of $11.45gL^{-1}$ was obtained after 5 days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.390-396
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• 2009

To select optimal shade material in paddy soil, growth characteristics and ginsenoside contents were investigated in new cultivar, 'Cheonpoong' of three-year-old ginseng cultured under three kinds of shade materials such as three-layered blue and one-layered black PE (polyethylene) net (TBPN), blue PE sheet (BPSS), and aluminium-coated PE sheet (APSS). The order of light transmission ratio and air temperature by shade materials were BPSS > APSS > TBSB among three shade materials. Average soil water tension in PDC and IDC was 64 mbar (absolute soil moisture, 25%) and 123 mbar (absolute soil moisture, 17%), respectively, and soil water tension in IDC was changed more distinctly than that of PDC by season and shade materials. Yield in PDC was distinctly decreased more than that in IDC because of the increase of discolored-leaf and rusted-root ratio. BPSS and TBPN among three shade materials were the most effective on the increase of yield in PDC and IDC, respectively. Ratio of rusty-colored root showed not significant difference by drainage class and shade materials. Contents of panaxatriol ginsenoside (Rg1, Re and Rf) were decreased in PDC, while it of panaxadiol ginsenoside (Rb1, Rc and Rd) were increased in IDC. Total ginsenoside contents of IDC was distinctly higher than that of PDC, and BPSS showed the highest contents among three shade materials regardless of poorly and imperfectly drainage class.