• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.97-104
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• 2016

This paper performed consolidation tests on soft ground with and without artesian pressure conditions to find out characteristics of leaching effects using two types of one-dimensional column equipment(height : 1,100mm, outer diameter : 250mm). Artesian pressure of 5.5kPa was applied to the bottom of soft ground inside column equipment. Distribution of salinity and shear strength with soil depth were measured after the consolidation test. From the results, it was found that distribution of undrained shear strength and salt concentrations were similar at the top of clay ground irrespective of artesian pressure condition. However, at the bottom of clay ground, the values of undrained shear strength and salt concentration under artesian pressure were lower than those without artesian pressure. This result indicates that structure of soft soil with artesian pressure was weakened by salt leaching. Electronic resistance results showed that void ratio under artesian pressure condition was more reduced than that without artesian pressure condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1229-1235
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• 2015

Scaffold fabrication technology using a 3D printer was developed for damaged bone tissue regeneration. A scaffold for bone tissue regeneration application should be biocompatible, biodegradable, and have an adequate mechanical strength. Moreover, the scaffold should have pores of satisfactory quantity and interconnection. In this study, we used the polymer deposition system (PDS) based on fused deposition modeling (FDM) to fabricate a 3D scaffold. The materials used were polycaprolactone (PCL) and alginic acid sodium salt (sodium alginate, SA). The salt-leaching method was used to fabricate dual pores on the 3D scaffold. The 3D scaffold with dual pores was observed using SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) and evaluated through in-vitro tests using MG63 cells.

• Analytical Science and Technology
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• v.13 no.6
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• pp.712-721
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• 2000

$LiF-BeF_2-ZrF_4$(63-30-7 mol%) molten salt was dissolved up to 0.02g in 1ml of distilled water at room temperature. $ZrO_2$ oxide made from $ZrF_4$ through pyrohydrolysis was recovered by leaching in distilled water with $LiF-BeF_2-ZrF_4$molten salt including it at room temperature. The crystalline sharpness of recovered $ZrO_2$ oxide was not damaged.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.15-23
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• 2004

Deicer operations provide traffic safety during winter driving conditions in urban areas. Using large quantities of de-icing chemicals (i.e., $CaCl_2$ and NaCl) can cause serious environmental problems and may change behaviors of heavy metals in roadside sediments, resulting in an increase in mobilization of heavy metals due to complexation of heavy metals with chloride ions. To examine effect of de-icing salt concentration on the leaching behaviors and mobility of heavy metals (cadmium, zinc, copper, lead, arsenic, nickel, chromium, cobalt, manganese, and iron), leaching experiments were conducted on roadside sediments collected from Seoul city using de-icing salt solutions having various concentrations (0.01-5.0M). Results indicate that zinc, copper, and manganese in roadside sediments were easily mobilized, whereas chromium and cobalt remain strongly fixed. The zinc, copper and manganese concentrations measured in the leaching experiments were relatively high. De-icing salts can cause a decrease in partitioning between adsorbed (or precipitated) and dissolved metals, resulting in an increase in concentrations of dissolved metals in salt laden snowmelt. As a result, run-off water quality can be degraded. The de-icing salt applied on the road surface also lead to infiltration and contamination of heavy metal to groundwater.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.4
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• pp.37-49
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• 2001

This study was performed in order to produce the basic data for developing prediction techniques of desalinization to be applicable to reclaimed tidal lands at the beginning stage. the desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage. The 5 soil samples used in this study were collected in 4 tidal land reclamation projects. Regression equations were obtained in order to investigate the changes of electrical conductivity during the desalinization of reclaimed tidal lands and to estimate water requirements for desalinization. The results obtained from this study were summarized as follows: 1. According to USDA Salinity Laboratory classification system of salt affected soils the reclaimed tidal land soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. With the increase of the water requirements for desalinization the electrical conductivity was decreased with high degree of correlationships and the desalinization effects were remakable in both the leaching method and the rinsing method. 3. In case of the leaching method the electrical conductivity had been reduced below the classification value of salt affected soils when the depth o water leached per unit depth of soil (Dwl/Ds) was 0.3 and the desalinization effects showed a tendency to be much the same in each treatment.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.369-377
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• 2014

This study was carried out to evaluate the effect of rice husk (RHB) and food waste biochar (FWB) on upland soil with sandy loam texture, in terms of physico-chemical analysis, lettuce seed germination test, and orgainc carbon leaching experiment. RHB and FWB had different physico-chemical properties each other. Carbon to nitrogen ratio (C/N ratio) of RHB was 32, showing two times higher than that of FWB. FWB had high salt and heavy metal content, compared to RHB. This is probably due to different ingredients and production processing between two biochars each other. Results of germination test with Lettuce showed lower germination rate when FWB was applied because of higher salt concentration compared to control and RHB. Organic carbon leaching test using saturated soil column (${\Phi}75{\times}h75mm$) with $10MT\;ha^{-1}$ biochar application rate, showed higher saturated hydraulic conductivity in rice husk biochar treatment column, compared to control and food waste biochar treatment. The highest total organic carbon concentration in column effluent was lower than those in both of rice husk biochar and food waste biochar, whereas the differences was negligible after 9 pore volumes of effluent. Consequently, biochars from byproducts such as rice husk and food waste in sandy loam textured upland soil could enhance a buffer function such as reduction of leaching from soil, but the harmful ingredient to crops such as high salt and heavy metals could limit the agricultural use of biochars.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.86-92
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• 2016

In this study, we used a polymer deposition system, based on fused deposition modeling, to fabricate the 3D scaffold and then fabricated micro-pores on a 3D scaffold using a salt leaching method. Materials included polycaprolactone (PCL) and sodium chloride (NaCl). The 3D porous scaffolds were fabricated according to blending ratio such as PCL (70 wt%)/NaCl (30 wt%) and PCL (50 wt%)/NaCl (50 wt%). The 3D porous scaffolds were observed by scanning electron microscopy. The results showed that 3D porous scaffolds had a deposition width of $500{\mu}m$, contained a pore size of $500{\mu}m$ and below $100{\mu}m$. To evaluate the 3D porous scaffolds for bone tissue engineering, we carried out the cell proliferation experiment using a CCK-8 and a mechanical strength test using a universal testing machine. In summary, the 3D porous scaffold was found to be suitable for cancellous bone of human in accordance with the result of in-vitro cell proliferation and mechanical strength. Thus, a 3D porous scaffold could be a promising approach for effective bone regeneration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.865-871
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• 2016

In recent years, traditional scaffold fabrication techniques such as gas foaming, salt leaching, sponge replica, and freeze casting in tissue engineering have significantly limited sufficient mechanical property and cell interaction effect due to only random pores. Fused deposition modeling is the most apposite technology for fabricating the 3D scaffolds using the polymeric materials in tissue engineering application. In this study, 3D slurry mould was fabricated with a blended biphasic calcium phosphate (BCP)/Silica/Alginic acid sodium salt slurry in PCL mould and heated for two hours at $100^{\circ}C$ to harden the blended slurry. 3D dual-pore BCP/Silica scaffold, composed of macro pores interconnected with micro pores, was successfully fabricated by sintering at furnace of $1100^{\circ}C$. Surface morphology and 3D shape of dual-pore BCP/Silica scaffold from scanning electron microscopy were observed. Also, the mechanical properties of 3D BCP/Silica scaffold, according to blending ratio of alginic acid sodium salt, were evaluated through compression test.

• Polymer(Korea)
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• v.38 no.2
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• pp.150-155
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• 2014

Polycaprolactone (PCL) is a synthetic biodegradable polymer with excellent mechanical properties. $TiO_2$ (titanium dioxide) has a hydrophilic, high density and excellent biocompatibility. In this work, we produced three-dimensional porous scaffolds with PCL and $TiO_2$ nanoparticles using a salt-leaching method. Physical properties of the scaffolds were analyzed by FE-SEM, FTIR, TGA and compressive strength. Interestingly, the addition of $TiO_2$ nanoparticles decreased the water absorption and swelling ratio of the porous scaffolds. However, the compressive strength was increased by $TiO_2$. CCK-8 assay, which is generally used for the analysis of cell growth, shows that $TiO_2$ nanoparticles have no cytotoxicity. Taken together, we suggest that the PLC/$TiO_2$-scaffold can be used for biomedical applications.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11b
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• pp.176-181
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• 2005

The electrolytic reduction process and the electrorefining process, which are being developed at the Korea Atomic Energy Research Institute (KAERI), are to generate molten waste salts such as LiCI salt and LiCI-KCI eutectic salt, respectively. Our goal in waste salt management is to minimize a total waste generation and fabricate a very low­leaching waste form such as a ceramic waste form. Zeolite has been known to one of the most desirable media to immobilize waste salt, which is water soluble and easily radiolyzed. Zeolite can be also used to the removal of fission products from the spent waste salt. Molten LiCI salt is mixed with zeolite A at $650^{\circ}C$ to form a salt-loaded zeolite, and then thermally treated in above $900^{\circ}C$ to become an immobilized product with crystal phase of $Li_{8}Cl_{2}$-Sodalite. In this work, a crystal phase changes of immobilization medium, zeolite, during immobilization of molten LiCI salt using zeolite A is introduced.