• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2016.05a
• /
• pp.259-260
• /
• 2016

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.11a
• /
• pp.111-113
• /
• 2011

This study investigated about how much the limestone's volume was changed as time passed while maintaining a certain level of moisture condition in the limestone material for concrete under high temperature. The result is summarized as follows: It was appeared that the limestone material under high temperature emitted some CO₂ resulting from the decarboxylation, so that as the heating temperature was increased, the limestone's length change rate was decreased. In the leave time change after heating the stone, the both conditions of 50% and 100% made the limestone create Ca(OH)₂ using some H₂O. So it was appeared that as time passed, the limestone's length change rate first increased because of its volume expansion, but the rate was reduced after the limestone material was crumbled.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.5
• /
• pp.483-487
• /
• 2001

As a part of basic investigation for utilizing of cuttle bone as a calcium source, we examined on the extraction methods (calcining at $800^{\circ}C$ for 2 hrs, autoclaving at $121^{\circ}C$ for 10 hrs and ultrasonic treatments at $60^{\circ}C$ for 10 hrs) as a pretreatment methods for preparation of calcium-based powder from cuttle bone, The color of calcined calcium-based powder from cuttle bone was white, while that treated by other methods was light yellow. The calcium content in calcined calcium-based powder was $70.5\%$, and revealed high about 2 times compared to those pretreated by other methods. And, calcium solubility in calcined calcium-based powder was improved 22 times compared to raw cuttle bone powder, Among calcining, autoclaving and ultrasonic treatments as a pretreaoent methods for preparation of calcium-based powder from cuttle bone, calcining treatment was superior to other methods on the aspect of color, calcium solubility and purity of calcium-based powder, Judging from X-ray diffraction pattern of calcined calcium-based powder, most of calcium was present as a form of calcium oxide, But, pH of calcined calcium-based powder revealed strong alkali of pH 12.9. This pH value might invoke health risk in using food resource. Therefore, for utilization effectively calcined calcium-based powder from cuttle bone, it requires a suitable treatment such as adjustment of pH to neutral condition.

• Clean Technology
• /
• v.19 no.4
• /
• pp.453-458
• /
• 2013

Fly ash has capacity to oxidize or adsorb mercury in a flue gas. Mercury oxidation and adsorption efficiencies of fly ash vary depending on the properties of fly ash. This study was designed to understand reaction characteristics of mercury with fly ash components. The fly ash components were tested to determine their oxidation and adsorption capabilities for elemental mercury and oxidized mercury. A sample was synthesized with fly ash components and tested. The test results were compared with those of the fly ash sample obtained from a coal-fired power plant. $Fe_2O_3$, CuO and carbon black showed higher oxidation or adsorption efficiency for elemental mercury while CaO, MgO, CuO and carbon black showed higher adsorption efficiency for mercury chloride. In addition, the synthesized sample showed comparable mercury oxidation and adsorption efficiencies to the fly ash sample.

• Clean Technology
• /
• v.3 no.2
• /
• pp.87-93
• /
• 1997

A new process has been developed for nitrate and other salts removals from polluted waters. Alumina cement and calcium oxide served as precipitating agents to remove nitrate with stirring at basic pH. Low content of alumina in the commercialized alumina cements resulted in a increasing in nitrate removal yield. It is found that the compositions of aluminium and calcium are the most important factors in successful nitrate insolubilization. In order to remove high concentration of nitrate in polluted water, multi-stage precipitation was found to be very effective. Sulfate, chloride, and phosphate ions as well as nitrate were also removed by the precipitated reaction. After precipitation, post-treatments including Na2CO3 addition and neutralization with acid alleviated the level of aluminium and calcium in the treated water.

• Journal of Applied Biological Chemistry
• /
• v.65 no.4
• /
• pp.457-462
• /
• 2022

Manganese (Mn) exists in various oxidation states and Mn(II) is the most mobile species of Mn, which is toxic to plants and limits their growth. Therefore, the purpose of this study was to reduce Mn toxicity by immobilizing Mn using various adsorbents including iron oxides and calcium compounds. Ferrihydrite, schwertmannite, goethite were synthesized, which was confirmed by X-ray diffraction. Hematite was purchased and used as Mn adsorbent. Calcium compounds such as CaNO₃, CaSO₄, and CaCO₃ were used to increase pH and oxidize Mn. For Mn adsorption, Mn(II) solution was reacted with four iron oxides, CaNO₃, CaSO₄, and CaCO₃ for 24 hours, filtered, and the remaining Mn concentrations in the solution were analyzed by inductively coupled plasma optical emission spectroscopy. The adsorption rate and adsorption isotherm were calculated. Among iron oxides, the adsorption rate was highest for hematite followed by ferrihyrite, but goethite and schwertmannite did not adsorb Mn. In the case of calcium compounds, the adsorption rate was high in the order of CaCO₃>CaNO₃>CaSO₄. In conclusion, treatment of CaCO₃ was the most effective in reducing Mn toxicity by increasing pH.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.413-416
• /
• 2004

매립장 침출수로 인해 오염된 매립장 주변 지하수 정화를 위한 실내실험을 실시하였다. 오염물로는 대표적 염화용제인 TCE와 PCE, 그리고 중금속인 As, Cd, Cr, Pb에 대하여 Air-sparging, 오존 산화법, 화학적 처리방법에 의한 정화효율 실험을 실시하였다. Air-sparging은 TCE, PCE에서 높은 제거효율을 가졌으며, 오존 산화법은 Cr, Pb에서 제거 효율이 좋았다. 반응제를 첨가한 공침방법의 경우, 모든 중금속에 대하여 소석회 첨가시 매우 높은 제거효율을 보였으며, As는 황산제일철에서, Cd, Cr, Pb는 탄산칼슘과 제올라이트 첨가시 높은 제거효율을 나타내었다. 실험결과로부터, 유기오염물과 중금속이 혼합되어 나타나는 매립장 주변 오염 지하수의 경우 휘발성 유기오염물의 제거를 위해서는 폭기방법이, 중금속의 경우에는 공침방법에 의해 수산화물, 탄산염으로 만들어 고형물로 처리하는 방법이 제거효과가 좋은 것으로 나타났다.

• The Korean Journal of Pharmacology
• /
• v.29 no.2
• /
• pp.195-202
• /
• 1993

Oxidative modification of cellular proteins and lipids may play a role in the development of diabetic complications. Diabetic cardiomyopathy has been suggested to be caused by the intracellular $Ca^{2+}$ overload in the myocardium, which is partly due to the defect of calcium transport of the cardiac sarcoplasmic reticulum (SR). In the present study, the possible mechanism of the functional defect of cardiac SR in diabetic rats was studied. Both of the maximal $Ca^{2+}$ uptake and the affinity for $Ca^{2+}$ were decreased in the diabetic rat SR in comparison with the control. To investigate whether the functional defect of the cardiac SR in streptozotocin-induced diabetic rat is associated with the oxidative changes of cardiac SR proteins, the carbonyl group content and glycohemoglobin levels were determined. The increase in carbonyl group content of cardiac SR (2.30 nmols/mg protein, DM; 1.78, control) and in glycohemoglobin level $(13{\sim}17%,\;DM;\;3{\sim}5%,\;control)$ were observed in the diabetics. The extent of increase in calcium transport by phospholamban phosphorylation was greater in the diabetic cardiac SR membranes than that in the control. The phosphorylation levels of phospholamban, as determined by SDS-PAGE and autoradiography with $[{\gamma}^{32}P]ATP$, were increased in diabetic cardiac SR. These results suggest that the impaired cardiac SR function in diabetic rat could be a consequence of the less-phosphorylation of phospholamban in the basal state, which is partly due to the depleted norepinephrine stores in the heart. Furthermore, the oxidative damages in cardiac SR membranes might be one of the additional factors leading to the diabetic cardiomyopathy.

• Korean Journal of Food Science and Technology
• /
• v.35 no.3
• /
• pp.410-416
• /
• 2003

Effects of calcium and chitosan treatments on storage and quality of pork were investigated. Porks were coated with 1% each of 30 and 120 kDa chitosans in 3% gelatin solution. Self-life and antioxidation increased significantly in all samples. In contrast with non-treated group, pH of the chitosan-treated group was very stable. Moisture content and water activity (Aw) were similar among all samples. Water-holding capacity decreased slightly, whereas cooking loss increased, during storage in all samples. Value of redness increased in chitosan-coated pork. Tenderness of pork injected with calcium was the highest among all samples. These results showed that preservation and quality of pork were improved by the treatment of calcium and 30 kDa of chitosan.

• Analytical Science and Technology
• /
• v.5 no.4
• /
• pp.401-408
• /
• 1992

The ion-selectrodes based on calcium ferrite were prepared by mixing calcium oxide with ferric oxide on molar ratio of 0.6:1.4, 0.8:1.2, 1.0:1.0, respectively. The specimens were sintered at $1400^{\circ}C$ for 2hrs in $O_2$ and for 20min in $H_2$ atmosphere. The selectrode sintered in hydrogen atmosphere showed better responded potential and wider range of responded concentration than selectrode sintered in oxygen atmosphere. The ion-selectrodes base on calcium ferrite(0.6:1.4 molar ratio.) showed the highest potential to bivalent cations such as $Ca^{2+}$, $Ba^{2+}$, $Mg^{2+}$, $Zn^{2+}$ and halogen anions such as $I^-$, $Br^-$ in the range of $10^{-1}{\sim}10^{-7}M$. It showed good agreement with theoretical nernstian values.