• Proceedings of the KSEEG Conference
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• 2005.04a
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• pp.120-124
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• 2005

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.237-249
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• 2019

The roughness changes on a fracture surface were analyzed via a multi-stage compression test under high temperatures to assess how the cracks in a rock mass affect groundwater movement. The analyzed samples consist of coarse granitic rocks from approximately 40 and 270 m depth, and fine granitic rocks from 500 m depth. The compression test was conducted on $20{\times}40{\times}5mm$ samples using a loading system where the pressure increases in 10 MPa increments to 120 MPa. A high-resolution 3D confocal laser scanning microscope (CLSM) was used to observe the surface changes, including the roughness changes, at each pressure step. The roughness change was calculated based on the roughness factor. The experimental results indicate that the roughness of the fracture surface varies with rock type under the stepwise pressure conditions. These data provide a basis for predicting groundwater flow along rock fractures.

• Magazine of the Korean Society of Agricultural Engineers
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• v.7 no.1
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• pp.888-899
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• 1965

• Tunnel and Underground Space
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• v.32 no.1
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• pp.1-19
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• 2022

In this report, new standard, published by Japanese Geotechnical Society, on in-situ stress measurements by hydraulic fracturing was reviewed. In the standard, modification was made for the calculation of fracture re-opening pressure in consideration of fracture surface roughness and residual aperture. The standard also presents how much the system compliance influences the estimation of the fracture re-opening pressure and subsequent in-situ stresses. It is shown that the stiffer the rock mass is, the system compliance should be sufficiently small enough so as to obtain in-situ stress measurement with higher confidence.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.417-422
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• 1998

This study was performed to obtain information about the extraction conditions of lipids from microalgae, Spirulina platensis, using supercritical fluid $CO_2$. Regardless of extraction temperature conditions, the extracted lipid contents increased as pressure increased, but decreased at 8500 psi on each temperature. The highest yield of extracted lipid content showed in the condition of 5500psi at $50^{\circ}C$, and extracted lipid content was about $20\%$. In same pressure the contents of C18 : 2 and C20 : 0 increased as temperature increased, but fatty acids composition were $60\~75\%$ saturated, $12\~20\%$ monounsaturated and $13\~31\%$ polyunsaturated regardless of extraction conditions. The C18 : 3 was only detected in the condition of 5500psi at $50^{\circ}C$ but the content was very little.

• The Journal of the Petrological Society of Korea
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• v.3 no.3
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• pp.185-195
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• 1994

An experimental study of iron-aluminium partitioning between synthetic garnet and synthetic epidote was carried out, as equilibrium was maintained in the exchange reaction expressed as follows : $Ca_3Fe_2Si_3O_12\+\2\Ca_2Al_2AlSi_3O_12$(0H) = $Ca_3Al_2Si_3O_12\+\Ca_2Al_2FeSi_3O_12$(0H) Temperature has a pronounced effect on the distribution of Fe and A1 between the minerals. However, the pressure effect is not so drastic as in the exchange reaction. With increasing temperature, $Fe^{+3}$ becomes redistributed from garnet into epidote, whereas A1 becomes redistributed from epidote into garnet. This is in line with the general principle of phase correspondence, as the temperature increases the more electropositive metal aluminium redistributes from epidote into garnet. The agreement between the experimental results of this study and the natural samples suggests that $K_D=X^{Ep}_{Fe}/X^{Gr}_{Fe}$ may be a useful geothermometer for metamorphic rocks containing garnet and epidote that are close to binary Fe-A1 compounds.

• The Journal of the Petrological Society of Korea
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• v.8 no.2
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• pp.92-105
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• 1999

The Cretaceous Chaeyaksan basaltic rocks consist mainly of basaltic tuffs intercalating three layers of basalt. Stratigraphically, the rocks are located between the upper Songnaedong Formation and the lower Geoncheonri Formation and contain plagioclase, augite, hornblende, and a few olivine phenocrysts. Geochemically, they show calc-alkaline characteristics in some immobile element content, but show the alkaline suite feature in the mobile major element composition. The basalts are widely spilitized but some of them is altered to shoshonitic rocks with more calcic plagioclase, calcite, and chlorite, and adularia veinlets are common in the rocks. It is supposed that the post-eruption alteration of the rocks is done through alkali-replacement by hydrothermal solution or vapor rather than by low grade regional metamorphism. It is considered that A1 in hornblende will be available for estimating the pressure of the pre-eruption magma in the reservoir although the plagioclase of the rocks are highly albitized. The crystallization pressure was calculated as 5.7Kb by the equation of Johnson and Rutherford(l989) incorporating of the effect of overestimate of .41T in hornblende in the case of quartz-free rocks. Application of the estimated temperature, pressure and the constituent of phenocrysts of the rocks to the experimental P-T phase diagram for basalts established by Green(1982) indicates the crystallization course and succession of growth of the phenocrysts during of rising and cooling of the magma reservoir; augite + augite and olivine + augite, olivine, and hornblende -+ augite and hornblende+ augite, hornblende, and plagioclase. Such evolution course of the magma may include crystal fractionation by the phenocrysts crystallization and contamination by country rock in lower crust.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.544-552
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• 2000

Norway has the geological of condition of hard bedrocks, high mountains, deep valleys and fjords. In this background many tunnels and rock caverns are developed. In this process of constructing tunnels and rock caverns Norway seems to have strong competitiveness in the construction of tunnels. In spite of high salaries to the tunnel workers, Norwegian contractors are probably producing the cheapest tunnels and rock caverns in the world. Besides benefit of hard-rock geology, Norwegian cost-saying is owing to the Norwegian excavation technique in hard rocks such as unlined pressure tunnels, air cushion chambers, underwater piercing, and reasonable contract system and organization of workers developed from the accumulated experience. Brief analytical description of them are given in this paper in order to stimulate the utilization of the underground spaces.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.482-486
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• 2013

Recently, biohydrocarbons are gathering an interest as a new bioenergy due to the versatile applicability. In the present work, a process is proposed for the recovery of lipids from Recombinant E. coli MG1655 which provides longer chain fatty acids. After the growth of the recombinant E. coli, the cells were disrupted by high pressure homogenizer for obtaining intracellular lipids and the resulting solutions were centrifuged and extracted. For the efficient cell disruption with high pressure homogenizer, the pressure higher than 5,000 psi was required. In addition, under the conditions of applied pressure 5,000 to 20,000 psi, 1~3 pass homogenizing was enough for the more than 90% cell disruption. As organic solvents for extraction of lipid, hexane/isopropyl alcohol and ethyl acetate/ethanol systems showed excellent extracting power. With these solvent systems, the 60% lipid could be recovered. Moreover it was found that the extracted lipids contained long-chain fatty acids such as $C_{12}$, $C_{14}$, $C_{16}$ and $C_{18}$.

• Economic and Environmental Geology
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• v.22 no.4
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• pp.371-379
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• 1989

Peak or near-peak metamorphic temperatures and pressures for Seosan area could be estimated from major element method. Temperatures calculated from garnet-biotite geothermoneter(Ferry and Spear, 1978; Ganguly and Saxena, 1984) are $620{\pm}40^{\circ}C$ and $520{\pm}20^{\circ}C$ for Seosan and Daesan Formation respectively. Presures derived from garnet-plagiciase-$Al_2Si_O_2$-quartz geobarometer(Newton and Haselton, 1981; Ganguly and Saxena, 1984)suggest 5-6kb for both of Seosan and Daesan Formation. These results suggest that under isobaric, Seosan Formation underwent relatively high temperature metamorphism compared with Daesan Formation. Chemical zonations of garnet for major elements such as Fe, Mg, and Mn in Seosan and Dasan Formation show different patterns each other probably caused by different thermal history.