• Journal of Pharmaceutical Investigation
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• v.38 no.2
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• pp.111-117
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• 2008

To overcome the solubility of poorly water-soluble drug, the formation of solid dispersion using a spray-dryer with polymeric material, that can potentially enhance the dissolution rate extend of drug absorption was considered in this study. $Eudragit^{(R)}$ E100 as carrier for solid dispersion is acrylate copolymer that soluble in acidic buffer solutions (below pH 5.0). It was used to increase dissolution of atorvastatin calcium as a water-insoluble drug in acidic environments. In this study, a spray-dryer was used to prepare solid dispersion of atorvastatin calcium and $Eudragit^{(R)}$ E100 for purpose of improving the solubility of drug. Atorvastatin calcium and $Eudragit^{(R)}$ E100 were dissolved in ethanol and spray-dryed. DSC and XRD were used to analyze the crystallinity of the sample. It was found that atorvastatin calcium is amorphous in the $Eudragit^{(R)}$ E100 solid dispersion. FT-IR was used to analyze the salt formation by interaction between atorvastatin calcium and $Eudragit^{(R)}$ E100. Comparative dissolution study exhibited better dissolution characteristics than the commercial drug ($Lipitor^{(R)}$) as control. The dissolution rate of atorvastatin calcium was markedly increased in solid dispersion system in simulated gastric juice (pH 1.2). This study proposed that this solid dispersion system improved the bioavailability of poorly water-soluble atorvastatin calcium.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.415-423
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• 2009

The purpose of this study is to investigate the response of human pulp cell on Portland cement mixed with $\beta$-glycerophosphate. To investigate the effect of $\beta$-glycerophosphate and/or dexamethasone on human pulp cell, ALP activity on various concentration of $\beta$-glycerophosphate and dexamethasone was measured and mineral nodule of human pulp cell was stained with Alizarin red S. MTS assay and ALP activity of human pulp cell on Portland cement mixed with various concentration of $\beta$-glycerophosphate (10 mM, 100mM, 1M) was measured and the specimens were examined under SEM. Addition of $\beta$-glycerophosphate or dexamethasone alone had no effect however, the addition of 5 mM $\beta$-glycerophosphate and 100 nM dexamethasone had the largest increasement in ALP activity. There was no toxicity in all samples and the data showed that Portland cement mixed with 10 mM $\beta$-glycerophosphate had more increase in ALP activity compared with control. In conclusion, Portland cement mixed with $\beta$-glycerophosphate has no toxicity and promotes differentiation and mineralization of pulp cell compared with additive-free Portland cement. This implicated that application of Portland cement mixed with $\beta$-glycerophosphate might form more reparative dentin and in turn it would bring direct pulp capping to success.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.200-207
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• 2019

Cement is one of the most commonly used materials in the construction and civil engineering industry. However, emissions of carbon dioxide generated during the production of cement have been linked to climate change and environment pollutants. In order to replace cement, many studies have been actively performed research to utilizing Blast Furnace Slag(BFS), which is a byproduct of the steel industry. This study aims to investigate the physiochemical properties of the BFS powder based grout to determine whether it can be used as an environment-friendly grout material. As a fine powder, BSF can be used instead of cement grout due to its potential hydraulic property. BSF has also been known for its ability to strengthen materials long-term and to densify the internal structure of concrete. In order to investigate the physicochemical properties of the BFS powder based grout as a grout material, in this study assessment tests were performed through a gel-time measurement, uniaxial compressive strength, and chemical resistance tests, and heavy-metal leaching test. Characteristics and advantages of the slag were studied by comparing slag and cement in various methods.

• Journal of the Korean GEO-environmental Society
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• v.12 no.12
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• pp.21-30
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• 2011

The recycled soil that is proceeded from demolition concrete structures was analyzed by the methods of the physical and mechanical tests of soil and TCLP test to use the soil in low landfilling for the construction of an industrial complex. The laboratory test for diffusion of alkali ion in soil mass was analyzed by the methods of XRF and ICP. The fish toxicity test was also conducted to find an environmental influence. The recycled soil through the laboratory test satisfied the engineering property for low landfilling and the criteria of soil contamination. However, the solution which producted by 1:1 ratio of recycled soil and water contained the high pH concentration by alkali ion. The calcium hydroxide solution by CSH cement paste was estimated as the main reason why pH concentration is increased more than 9.0. The high pH concentration in recycled soils causes a toxicity to the livability of fishes. A diffusion area of pH concentration in the ground was analyzed by the Visual Modflow Ver. 2009 program based on geotechnical investigation. The high pH concentration in the recycled soils can be remained as high value due to cement paste in the long term period. Therefore, in the early stage of landfilling work, the mixing with the weathered granite soil is necessary to control the pH concentration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.492-499
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• 2021

In this study, the benthic environmental and microbial community structure were investigated by mixing granulated coal ash(GCA) and contaminated estuary sediments. Estuary sediments and GCA were mixed in a ratio of 8:2 and allowed to interact for 1 month, then sediment environmental factors were investigated. The pH of the experimental sediment was mixed increased to 11. The concentration of DIP(Dissolved inorganic phosphorus) in the experimental case decreased by 30 % compared to the control case, and this should be due to formation of calcium phosphate through the chemical reaction of DIP and calcium which diluted from GCA. The high abundance of Gammaproteobacteria seen in the experimental sediment compare to the control can af ect the DIP reduction. The DIN(Dissolved inorganic nitrogen) concentration increased over two times in the experimental case than the control, and this should be due to the high pH condition and release of NH₄⁺-N from the GCA. Microorganisms related to nitrogen circulation were not identified in both the control and experimental cases. It was confirmed that the GCA were effective in reducing the DIP concentration in contaminated estuary sediment, and that benthic microbial communities were shown to influenced the phosphorus circulation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.33-40
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• 2021

The objective of this work is to prove a possibility of void f illing through a carbonation f or the purpose of improving the quality of recycled aggregate. Carbonation can permanently immobilize CO2, which is a greenhouse gas, and thus provides additional benefit on environment. In this work, recycled fine aggregate was reacted using gaseous CO2 and supercritical CO2(scCO2) in a closed chamber, and the changes in physical properties of the recycled f ine aggregate bef ore and af ter carbonation were analyzed using the apparent density, skeletal density, pH, and FE-SEM measurements. Thereafter, a mortar specimen was prepared and a compressive strength was measured. According to the experimental results, it was found that the increase in the apparent density and the true density was higher by the reaction with scCO2, which was conducted at high temperature and high pressure compared to the reaction with gaseous CO2. In addition, the pH of the eluted water was found to have a larger initial decrease than that observed with samples from reaction by gaseous CO2. The shape and amount of calcium carbonate crystals were also found to be larger than that from gaseous CO2. The increase in compressive strength was the largest when using recycled fine aggregate reacted with scCO2. It was clear that quality improvement of recycled fine aggregate was higher with scCO2 than with gaseous CO2.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.87-95
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• 2023

Recently, redevelopment of the original downtown area is underway, the necessity of construction in adjacent location is increasing. However, excavations in dense urban areas are prone to ground problems due to various causes, so it is necessary to use materials and methods that can minimize such problems. As a general earth retaining method, various methods such as diaphragm wall and CIP method are applied using cement. However, since a large amount of cement is used for the installation of earth retaining method, it is necessary to conduct research on the development of new cement substitute materials to significantly reduce greenhouse gas emissions. In this study, we utilized the hardening reaction of blast furnace slag powder, desulfurized gypsum and high calcium fly ash by alkali activation and applied it to the SCW method. As a result, it was analyzed that the compressive strength of solidified soil using development solidification material was 96.2 ~ 106.3% of OPC at 28 days of curing. In addition, the strength increment ratio was 2.06 for sandy soil and 2.41 for clayey soil, which was higher than 1.85 of OPC. It seems an advantageous in terms of long-term strength. In addition, from the environmental point of view, it was analyzed that there is no elution of heavy metals and that greenhouse gas emissions can be dramatically reduced. Therefore, if further studies are conducted, it can be applied to the SCW method.

• Culinary science and hospitality research
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• v.20 no.2
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• pp.65-78
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• 2014

This study was aimed to develop short necked clam stock, which is the base of sauce, soup, etc., using various nourishing elements in short necked clams. In short necked clam stock with different heating times, the moisture content was significantly different (p < 0.05). For the color value of short necked clam stock, L value was the highest in S1(31.15), while the highest a value was found in S5(-0.36) and the highest b value in S5(0.67). pH was the lowest as 7.35 in S5. When heating time increased, pH decreased significantly (p < 0.001). The sugar content was the highest as $3.30^{\circ}Brix$ in S5 and the lowest as $2.63^{\circ}Brix$ in S1. The salinity content was the lowest as 0.73% in S1, and it increased significantly(p < 0.001) with increased heating time. Na was the highest among the mineral contents and the highest K, Mg, Ca, Fe contents were found in S5 heated for 60 mins. Twenty one kinds of free amino acid were detected in short necked clams. The highest essential amino acid content was arginine, the highest flavor enhancing free amino acid was glycine, and the highest derivative amino acid was taurine. The test for characteristic differences of short necked clam stock showed that savory taste and savory flavor of S4 heated for 50 mins were the highest. According to the results of acceptance test, S3 showed the best results. In conclusion, short necked clam stock showed great preference with increased heating time, and the preference has increased when it was simmered for 35~40 mins.

• Journal of the Korea Concrete Institute
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• v.29 no.4
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• pp.415-424
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• 2017

The purpose of this study is to investigate the effect of sulfate (${SO_4}^{2-}$) and magnesium ($Mg^{2+}$) ions on sulfate resistance of Alkali-activated materials using Fly ash and Ground granulated blast furnace slag (GGBFS). In this research, 30%, 50% and 100% of GGBFS was replaced by sodium silicate modules ($Ms(SiO_2/Na_2O)$, molar ratio, 1.0, 1.5 and 2.0). In order to investigate the effects of $Mg^{2+}$ and ${SO_4}^{2-}$, compression strength, weight change, lengh expansion of the samples were measured in 10% sodium sulfate ($Na_2SO_4$), 10%, 5% and 2.5% magnesium sulfate ($MgSO_4$), 10% magnesium nitrate ($Mg(NO_3)_2$), 10% [magnesium chloride ($MgCl_2$) + sodium sulfate ($Na_2SO_4$)] and 10% [magnesium nitrate $(Mg(NO_3)_2$ + sodium sulfate ($Na_2SO_4$)] solution, respectively and X-ray diffraction analysis was conducted after each experiment. As a result, when $Mg^{2+}$ and ${SO_4}^{2-}$ coexist, degradation of compressive strength and expansion of the sample were caused by sulfate erosion. It was found that the reaction of $Mg^{2+}$ with Calcium Silicate Hydrate (C-S-H) occurred and $Ca^{2+}$ was produced. Then the Gypsum ($CaSO_4{\cdot}2H_2O$) was formed due to reaction between $Ca^{2+}$ and ${SO_4}^{2-}$, and also Magnesium hydroxide ($Mg(OH)_2$, Brucite) was produced by the reaction between $Mg^{2+}$ and $OH^-$.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.704-712
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• 2006

This research was designed to investigate the removal of heavy metals, such as $Al^{3+}$, $Cu^{2+}$, $Mn^{2+}$, $Pb^{2+}$ and $Zn^{2+}$, by adsorption on clay minerals. Bentonite(Raw-Bentonite), $Ca^{2+}$ and $Na^+$ ion exchanged bentonite(Ca- and Na-Bentonite) and montmorillonite, such as KSF and K10 from Sigma Aldrich, were used as adsorbents. The component of five inorganic adsorbents was analyzed by XRF, and the concentration of metal ions was measured by ICP. The cation exchange capacity(CEC) and the particle charge of adsorbents were measured. The initial concentration range of metal ions was $10{\sim}100$ mg/L. From the experimental results, it was shown that the adsorption equilibrium was attained after $1{\sim}2$ hours. The maximum percentage removal of $Al^{3+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ on Na-Bentonite were more than 98% and that of $Mn^{2+}$ was 66%. $Al^{3+}$ was leached out from KSF with the higher concentration of hydrogen ion. Percentage removals of $Pb^{2+}$ and $Zn^{2+}$ on KSF were 88% and 59%, respectively. In general, the percentage removal of metal ions was decreased with the higher initial concentration of metal ions. The adsorption capacity of metal ions on Na-Bentonite was $1.3{\sim}19$ mg/g. Freundlich equation was used to fit the acquired experimental data. As the results, the adsorption capacity of metal ions was in the order of Na-Bentonite$\gg$Raw-Bentonite$\cong$K10>Ca-Bentonite>KSF. Freundlich constant, K of Na-Bentonite was the largest for metal ions. The order K of Na-Bentonite was Al>Cu>Pb>Zn>Mn, and the adsorption intensity(1/n) was determined to be $0.2{\sim}0.39$.