• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.3
• /
• pp.171-177
• /
• 2010

As concrete structures are exposed to chemical substances, damaged from salt, or progressed to the neutralization, the surface damage of the structures is generated timely fashion, resulting shortened service life. Especially, the sulfate erosion causes rapid surface defects, and the steel skeleton becomes corroded due to the water infiltration, generating stability deterioration of the concrete structure. In this study, the physical characteristics of the acid-resistant mortar with aluminosilicates was investigated in order to resolve problems of the acid resistance, one of the most serious problems of the cement type repair material. As the result of the experiment, the test specimen turned to exhibit almost equivalent physical characteristics with those of concrete sectional repair materials in terms of compressive and bending strengths. As both the cement sectional repair material and the test specimen were immerged in sulfuric acid solution to examine weight changes, the test specimens exhibited only 4% loss of their weights while the cement sectional repair materials reached at the level of 80% or above, proving the excellence acid resistant characteristics of the test specimens. Consequently, the physical characteristics of acid resistant mortar with aluminosilicates were revealed to be superior than those of concrete sectional repair materials. It can be utilized as a sectional repair material where the acidic erosion is anticipated.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.4
• /
• pp.642-648
• /
• 2012

To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.

• Food Science and Preservation
• /
• v.13 no.6
• /
• pp.720-725
• /
• 2006

This study was conducted to investigate extracting solution effect on the chemical compositions in different parts of Korean mountain Ginseng. Water, 80% EtOH and 80% MeOH are used as extraction solutions, and extracting conditions were 2 hr at $85^{\circ}C$ in water bath. The Brix(%) of the extract were ranged from $0.42{\sim}22.58%$, 80% EtOH extract for leaf is the highest level as 22.58%. The pH ranges of the extracts were $4.43{\sim}7.41$ and brown color of the extract was the highest with 1.803 in 80% EtOH extract for leaf, respectively. In case of hunter's color value of the extract, L value is the highest with 24.35 in 80% EtOH extract of seed, a and b value were the highest with 0.41 in 100% water extract of leaf and 3.69 in 80% MeOH extract of stem. Sucrose is the major free sugar of the extinct it highest content with 3673 mg% in 80% MeOH extract of mot and fructose is the highest with 1897 mg% in 80% MeOH extract of leaf, Major organic acids are identified as malic, tartaric and citric acid, and total organic acid content is the highest with 5,254 mg% in 80% MeOH extract of leaf and 1,527 mg% in 80% EtOH extract of leaf, The extracted major minerals ate P and K, P content highest with 15,563 ppm in 100% water extract of stem, K is 4,952 ppm in 80% MeOH extract of leaf, and Ca is the highest with 3,052 ppm in 1011% water extract of leaf. These results suggest that extracting solvent (80% MeOH) is concerned with the extract preparation of Korea Mountain Ginseng.

• Journal of environmental and Sanitary engineering
• /
• v.19 no.4 s.54
• /
• pp.9-18
• /
• 2004

In this study, the observation data for the yellow sandy dust phenomena from the year 1999 to 2003 at background sites in Korea were collected at Global Atmospheric Observatory at An-Myeon island and its temporal variation were analyzed. The chemical characteristics of the fine particles were also analyzed in order to evaluate sources of the yellow sandy dust particles. The results showed that the monthly average mass concentration of the fine particles was the highest in springtime and the lowest in summertime in general. The magnitude of its variation was also the highest in March in which the occurrence of yellow sandy dust was the most frequent and thus the number of samples was the largest, while the lowest in June through September. The yearly variation of ion components contributions to the total mass concentration of the fine particles was slowly decreasing, showing that $63\%$ in 1999, $59\%$ in 2000 and $56\%$ in 2003. The most prevalent ion components in the fine particles were found to be $NO_3$ and $SO_4^{2-}$, which are known to be source materials of acidic precipitation, and $NH_4^+$, a neutralizing material of the acid precipitation. Relative proportion of metal components in the fine particles was calculated as $14\%$ in average, and their concentrations are in an order of Fe > Al > Na > Ca > Zn > Pb > Cu > Mn > Ni > Cd > Cr > Co > U. The results indicated that main sources of the metals was soil-originated Fe, Al, Ca, and Mg, and the contribution of anthropogenic air Pollution-originated Zn, Pb, Cu, Mn were also high and keep slightly increasing. Statistical analysis showed that the chemical components could be divided into soil-originated group of Mg, Al, Ca, Fe, and Mn and air pollution-originated group of $NO_3$, Zn, Pb, and they are occupying more than $60\%$of all the components in the dusty sand. The results explain that An-Myeon island is more influenced by soil-originated source than ocean-originated one and also the influencing strength of anthropogenic poilution-originated source is less than $50\%$ of that of soil-originated sources. Compared to non-yellow sandy period, the yellow sandy dust period showed that the amounts of soil-originated $Mg^{2+}$ and $Ca^{2+}$ and ocean-originated $Na^+$ and $Cl^-$ were increased to more than double and the metals of Mg, Al, Ca, Fe were also highly increased, while micro metal components such as Pb, Cd, Zn, which have a tendency of concentrating in air, were either decreased or maintained at nearly constant level. In the period of yellow sandy dust, a strong positive correlation was observed between water soluble ions and between metals in terms of its concentration, respectively. Factor analysis showed that the first group being comprised of about $43\%$ of the total inorganic components was affected by soil and they are ions of $Na^+,\;Mg^{2+}\;and\;Ca^{2+}$ and metals of Na, Fe, Mn and Ni. The result also showed that the metals of Mg and Cr were classified as second group and they were also highly affected by soil sources.

• Applied Chemistry for Engineering
• /
• v.10 no.3
• /
• pp.415-418
• /
• 1999

The characteristics of VRLA (valve regulated Iead-acid) battery with the tubular positive plate and gel type electrolyte were examined as a function of active material filling density. The filling density of positive plate was 3.2 g/mL, 3.4 g/mL, and 3.6 g/mL, respectively. These VRLA batteries were cycled with 100% DOD (depth of discharge) at the $C_5/5$ rate, followed by IU-type recharge with $I_{max}=0.2C_{10}/10$ and a final voltage V=2.40 V/cell. The test was performed in a thermostatic room at $25{\pm}1^{\circ}C$. The result indicated that the initial capacity was independent of active material filling density, i.e., the highest initial capacity was 3.4 g/mL of filling density and the lowest was 3.6 g/mL. On aspect of the cycle-life performance of the VRLA battery, the filling density of 3.6 g/mL was similar to that of 3.4 g/mL in the positive plate, and both were higher than that of 3.2 g/mL. Water-loss and degradation of the VRLA battery were decreased according to an increase of the filling density in the positive plate. The optimum filling density of the active material was 3.4~3.6 g/mL.

• Food Science of Animal Resources
• /
• v.25 no.2
• /
• pp.156-161
• /
• 2005

This study was conducted to detennine the effect of dietary supplements of mineral powder (pegmatite) on the physico-chemical properties of M longissimuss for 24 Hanwoo steers. Each eight Hanwoo steers were randomly allotted to three treatments ; Control $(0\%)$, T1 (supplemented with pegmatite $2.0\%$ and vitamin A $0.2\%)$, T2 (supplemented with pegmatite $2.0\%$). Cooking loss was highest in control, while water holding capacity (WHC) was the highest in T2 (56.38) than the others. However, effect of the diets on meat color was not significantly different (p>0.05) Panel test scores of juiciness, tenderness and flavor of M longissinus were the highest for T1 $(4.6\~5.0)$ between the treatment group (p<0.05). The content of total fatty acid in M longissimus was the highest in T2 $(50.80\%)$ among the treatment group. Palmitic acid and oleic acid were siginificantly higher in T1 and control than those for the others(p<0.05). Unsaturated fatty acid (UFA) was highest in T2 $(58.57\%)$ than the others$(55.09\~55.64\%)$ (p<0.05).

• Economic and Environmental Geology
• /
• v.41 no.2
• /
• pp.183-199
• /
• 2008

This study is focused on characterization of the physio-chemical and mineralogical properties, investigation of their vertical changes in the tailing profile of the Guryoung mining area, classification of the profile into distinct zones, and condition conceptual model of physio-chemical conditions and phases-water relationships controlling the element behaviors in the tailings. The upper part of the groundwater is characterized by the high contents of $Fe_2O_3$ and $SO_3$ for whole rock analysis, low pH, and the occurrence of jarosite, schwertmannite and Fe-oxyhydroxide as the secondary mineral phases. The tailing profile can be divided into the covering soil, jarosite zone, Fe-sulfate zone, Fe-oxyhydroxide and gypsum-bearing pyrite zone, calcite-bearing pyrite zone, soil zone, and weathered zone on the based of the geochemical and mineralogical characteristics. The profile can be sampled into the oxidized zone and the carbonate-rich primary zone with the dramatic changes in pH and the secondary mineral phases. The conceptual model proposed for the tailing profile can be summarized that the oxidation of pyrite is the most important reaction controlling the changes in pH, the dissolution of the primary silicates and carbonates, the precipitation of secondary mineral phases, acid-neutralizing, and heavy metal behaviors through the profile.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.2
• /
• pp.132-135
• /
• 1998

This study was conducted to obtain basic information for soil improvement in flower crop cultivating greenhouse soil through survey on the chemical and physical properties of greenhouse soils. Total of 85 Flowcultivating farms were surveyed and analysis was done on the soil characteristics, amounts of chemical fertilizer and soil amendmentuse. The result are as follows: In soil properties of flower cultivating greenhousees, silt clay loam was 51%and 68% of the surveyed soils had good drainage condition. Ground water table was over 90-120cm which was optimum range for flower cultivation. Flower cultivating farms had problem with accumulation of fertility. Nitrate nitrogen was accumulated in Gypsophila paniculate farms and available phosphorus, and exchangeable postassium were significantly higher in greenhouse soils about 2 times than in open field soil. Application amount of chemical feltilizers in greenhouses were nitrate 211,phosphorus 135, and potassium 132kg/ha, respectively. Amount of organic matter used in greenhouse were high in order of cattle manure> compost> organic fertilizer> poultry manure> swine manure and their application amounts were69, 103, 32, 20, and 43 MT/ha, respectively.

• Korean Journal of Food Science and Technology
• /
• v.21 no.2
• /
• pp.283-288
• /
• 1989

The effect of storage temperature on the quality characteristics of meat sausage was investigated. Thus, the quality characteristic changes of meat sausage were discussed through physico-chemical and microbiological analysis. The results were summarized as follows; Volatile basic nitrogen(VBN) was increased more rapidly at $40^{\circ}C$ than at $10^{\circ}C$, $20^{\circ}C$ and fluctuating temperature $(10/40^{\circ}C)$. In physico-chemical analysis of meat sausage, the values of VBN , viable cell counts were increased with increase of temperature during storage, while thiobarbituric acid(TBA) values were fluctuated during storage as a whole. Water activity(Aw) and moisture contents showed a little change according to storage temperature, but sausage color was darkened as storage time goes by as a whole, the shelf-life was predicted above 40 days at $10^{\circ}C$, below 40 days at $20^{\circ}C$, below 30 days at $40^{\circ}C$ and about 20 days fluctuating temperature $(10/40^{\circ}C)$, respectively on the basis of slime formation in sensory evaluation.

• Korean Chemical Engineering Research
• /
• v.53 no.3
• /
• pp.364-371
• /
• 2015

For the cost down of polymer concrete, It is very important to reduce the use amount of polymer binder, which occupies most of the production cost of polymer concrete. Fly ash and atomizing reduction steel slag are spherical materials obtained from industrial by-products. Spherical atomizing reduction steel slag was manufactured using steel slag from reduction process of ladle furnace by atomizing technology. To investigate the physical properties of polymer concrete, polymer concrete specimens were prepared with the various proportions of polymer binder and replacement ratios of atomizing steel slag. Results showed that compressive and flexural strengths of the specimens were remarkably increased with the addition amount of polymer binder and the replacement ratios of atomizing steel slag. In the hot water resistance test, compressive strength, flexural strength, bulk density and average pore diameter decreased but total pore volume and pore diameter increased. We found that polymer concrete developed in this study reduced the amount of polymer binder by 18.2% compared to the conventional product because of the remarkable improvement of workability of polymer concrete using spherical fly ash and atomizing reduction steel slag instead of calcium carbonate (filler) and river sand (fine aggregate).