• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.51-59
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• 2021

In this study, the purpose of this study was to quantitatively grasp the specific correlation between the raw material and the occurrence of leakage by analyzing the characteristics of leakage by adjusting the type and content of the raw material constituting the asphalt mastic coating waterproofing material. To this end, two raw materials, CA (calcium carbonate) and ASE (anti-sedimentation), which are organic and mineral extender for asphalt mastic waterproofing membrane coating, were selected. viscosity and oil leakage stability (20 ℃, 40 ℃) was evaluated. As a result of the evaluation, the oil leakage stability and viscosity were inversely proportional to the CA average particle size, and it was quantitatively proven that a correlation in proportion to the ASE content was established. The results of this study are expected to be used as core data for basic mixing design in the future mixing studies to improve leakage of asphalt mastic waterproofing membrane coating.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.274-280
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• 2001

The chemical forms of calcium compounds in perilla leaves and their changes after harvest were investigated. The four types of calcium compounds extracted were as follows: water soluble calcium(F-I: mainly water soluble organic acid salts and calcium ion), IN-sodium chloride soluble calcium(F-II: calcium-pectate and calcium-carbonate), 2%-acetic acid soluble calcium(F-III: calcium-phosphate), and 5%-hydrochloric acid soluble calcium(F-IV: calcium-oxalate). The calcium content of perilla leaves was not found to vary with their age. Relatively high levels of F-l (28.4~39.5) and F-II (34.4~47.4) were found in young and mature leaves while the F-IV constituted 15.6~21.6% of the total calcium. The F-IV calcium contents of perilla. spinach and jaso were 16.8, 42.4 and 22.3%, respectively. In contrast to calcium. magnesium existed as water soluble magnesium at the highest content of 90.6% in spinach while 62.9% and 16.8% of the total magnesium existed as water soluble magnesium in perilla and jaso, repectively. The change in vitamin C and F-IV calcium content were examined for 7 days after harvest. Vitamin C content decreased slowly at the beginning but rapidly from the 4th day after harvest. On the other hand, the F-IV calcium content increased slowly at the beginning and rapidly from the 4th day of observation. This result suggests that the increase in F-IV calcium is related to the decrease in vitamin C content. This phenomena was more distinctly observed at 2$0^{\circ}C$ than 5$^{\circ}C$.

• Clean Technology
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• v.25 no.2
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• pp.114-122
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• 2019

The synthesis of bio polyol from renewable resources has attracted attention in recent years. In particular, it is important to take advantage of bio polyols in the synthesis of polymers. In this study, a series of dimethylformamide (DMF) based polyurethanes were synthesized using polycarbonate polyol/bio polyol (PO3G: polytrimethylene ether glycol prepared from 1, 3-propanediol produced by fermentation from corn sugar), methylene diphenyl diisocyanate (MDI) and 1,4-butandiol (BD). The properties of prepared polyurethane films and the cell structure of wet type artificial leather were investigated. As the bio polyol content increased, the tensile strength of polyurethane films decreased, however, the elongation at break increased significantly. As a result of thermal characteristics analysis, the glass transition temperature of polyurethanes increased when increasing the content of polycarbonate polyol. As a result of comparing the cell characteristics of wet type artificial leathers prepared in this study, it was found that the number and uniformity of cells formed in the artificial leather samples increased when increasing the content of polycarbonate polyol in polycarbonate polyol/bio polyol. From these results, it was found that DMF-based polyurethane containing an appropriate amount of bio polyol could be used for wet type artificial leather. The bio textile analysis system according to ASTM standard was used to measure the bio carbon content of polyurethane. The content of bio carbon increased proportionally with the increase of bio polyol content used in polyurethane synthesis.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.610-613
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• 2012

Oyster shell has a high content of $CaCO_3$ to be used as a acidic soil amendment. To enhance productivity of barley and soil microbe in an upland soil, oyster shell and calcium-magnesium carbonate were selected as a soil amendments in this study. A field experiment was treated no treatment (hereafter, control), oyster shell lime $3.09Mg\;ha^{-1}$ and $2.38Mg\;ha^{-1}$, and calcium-magnesium carbonate $2.38Mg\;ha^{-1}$ as amount of lime requirement in silt loam soil. The yield of barley from the oyster shell lime treatment was the highest. The protein content of barley was the highest of 11.1% in the calcium-magnesium carbonate, followed by 10.7% for the control, 10.6% for the oyster shell lime $3.09Mg\;ha^{-1}$, and 10.4% for the oyster shell lime $2.38Mg\;ha^{-1}$. Soil pH value was higher than that of control in harvesting stage. In addition, the population of soil bacteria was highest in oyster shell lime $2.38Mg\;ha^{-1}$, actinomycetes was highest in calcium-magnesium $2.38Mg\;ha^{-1}$. We concluded that the oyster shell lime can be effective to restore soil nutrient and microbe balance in an upland soil.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.111-120
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• 1993

We investigated in the existential forms of heavy metals and their distribution in plant and soil surrounding ruined mine in Daduk area. The content of heavy metals in soils was more plentiful in A soil than that in another soil, excepting only Mn. The content of Mn in soils was greater in B soil than those in another soils. The content of each heavy metals, according to existential form, had different patterns on the comparision of each elements ; organic-form on Cd and As, Carbonate-form Cu, Pb and Mn and Residual-form on Fe and Zn. The popularity ration of M. senensis and J. decipiens were about 65% and 72%, respectively, and which means that these plants had resistances to heavy metals. The contents of heavy metals absorbed in root was higher than those of stem except Mn, In M. sinensis, the contents of Zn in root was similar to that of stem. To study the heavy metal contents in water, the highest content of heavy metal, mainly Fe, Mn and Zn, were calculated in extracting water.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1266-1271
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• 2007

This study examined effects of calcium supplemented milk on bone loss in ovariectomized rats. Twenty four Sprague-Dawley female rats, 7 weeks-old, were divided into 4 groups, ovariectomized and fed diets containing: 1) control, no Ca supplemented milk, 2) ovx 1, Ca carbonate supplemented milk, 3) ovx 2, ionized Ca supplemented milk, and 4) ovx 3, nano Ca supplemented milk. All rats were fed 1 ml of milk containing 20 mg supplemented Ca. After 18 wk feeding, body weight gain and food efficiency ratio were significantly different between ovx 1 and ovx 3. Serum concentration of calcium and phosphorus were not different among groups. However, there was a significant difference in calcium content of dry femoral weight in ovx 3 compared with the control and ovx 2. In addition, femoral bone mineral density ($g/cm^2$) was significantly greater in ovx 3 than in other groups (p<0.05). The ovx 3 group showed the highest stiffness (N/mm), maximum energy (N) in femur and trabecular bone area (%). The present study indicated that nano Ca supplementation in milk may be an effective way to enhance bone calcium metabolism for ovariectomized rats.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.209-218
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• 1998

Ca-deficiency frequently observed in the hydroxyapatite powders prepared by precipitation which is known to be deleterious for its application to biomaterials was prevented by the technique developed in this study. In addition the prepared powder has been revealed to be quite active that full density is achieved at temperatures as low as 100$0^{\circ}C$ Instead of using N2 air was chosen as the processing atmosphere during the precipitation and aging of hydroxyapatite. {{{{ {CO }`_{3 } ^{2- } }} ions from the processing atmosphere(air) substitute partly for {{{{ {PO }`_{4 } ^{3- } }} ions in the hydroxyapatite and its content can be controlled by pH of the solution where the pre-cipitation reaction occurs.

• Analytical Science and Technology
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• v.5 no.1
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• pp.25-31
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• 1992

A benzene synthesizer was manufactured and has been used for the treatment of the various samples such as wood, charcoal, shell and soil for radiocarbon dating using liquid scintillation counter. The experimental conditions were optimized in each successive step of the synthesis of carbon dioxide, acetylene and the final product of benzene. Fifteen hours operation of the benzene synthesizer leads to product yields consistently in excess of 85% based on the content of calcium carbonate for the organic samples. Purity of the synthesized benzene was measured to be more than 99.9% by GC/MS.

• Journal of Environmental Impact Assessment
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• v.10 no.2
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• pp.85-98
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• 2001

This study was conducted to investigate the geochemical factors governing the distribution of heavy metals(Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the marine surface sediment samples collected from the Samcheonpo coal-fired power plant. Variations of absolute metal concentrations were related to those in textural and/or carbonate and organic matter content. Most elements, except for Pb, showed generally lower contents compared with the average shale concentration, and the effect of anthropogenic input appeared to be minimal in the sediments. Computations of LF%(labile fraction) and EF(enrichment factor) based on all trace metal data indicated the presence of mineralogical control for Co, Cr, Cu, Ni, and Zn, and anthropogenic contamination for Pb, which needs to be considered in the design of long term monitoring programmes.

• Ocean and Polar Research
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• v.24 no.2
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• pp.167-175
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• 2002

Sediment from six piston cores from the East Sea (Sea of Japan) was analyzed for evidence of paleoceanographic changes and paleoclimatic variation. A distinct geochemical boundary is evident in major element concentrations and organic carbon content of most cores near the 10-ka horizon. This distinctive basal Holocene change is interpreted to be largely the result of changing sediment sources, an interpretation supported by TiO_2/Al_2O_3$ ratios. Organic carbon and carbonate contents also differ significantly between the Holocene and glacial intervals. The C/N ratio of organic matter is greater than 10 during the glacial period, but is less than 10 for the Holocene, suggesting that the influx of terrigenous organic matter was more volumetrically important than marine organic matter during glacial times. The chemical index of weathering (CIW) is higher for the Holocene than the glacial interval, and changes markedly at the basal Holocene geochemical boundary. Silt fractions are higher in the glacial interval, suggesting a strong effect of climate on silt particle transportation: terrigenous aluminosilicates and continental organic carbon transport were higher during glacial times than during the Holocene. Differences in sediment composition between the Holocene and glacial period are interpreted to have been climatically induced.