• Journal of the Korean Recycled Construction Resources Institute
• /
• v.2 no.4
• /
• pp.360-366
• /
• 2014

In this study, effect of types and replacement ratio of alkali activator on compressive strength of ground granulated blast furnace slag mortar has been reviewed. Types of alkali activator are NaOH, $Ca(OH)_2$, $Na_2SO_4$, and KOH. Replacement ratio of alkali activator is 7.5, 10, 12.5, and 15%, respectively. As results, under high temperature curing condition, 1 day compressive strength development with NaOH and KOH was higher than that of $Ca(OH)_2$ and $Na_2SO_4$. Regardless of types of alkali activator, compressive strength increased with increasing pH. This can be explained by the fact that impermeable film on the surface of slag which is generated when slag contacts water has been destroyed by alkali activator, and this promotes hydration reaction. Also, 1 day age compressive strength of specimen with high temperature curing was higher than that of specimen with standard curing. 28 days age compressive strength of specimen with high temperature curing was less than or equal to that of specimen with standard curing.

• Journal of Environmental Health Sciences
• /
• v.26 no.2
• /
• pp.41-48
• /
• 2000

This study has been carried out to determine the seasonal characteristics of concentration of various ionic (CI-, NO3-, SO42-, Na+, NH+, K+, Ca2+) and heavy metallic (Pb, Mn, Cu, Ni) species in Pusan from August 1997 to April 1998. The concentrations of CI-, Na+, K+ were higher during summer with 2.98 ${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of but the concentration of NH4+ was higher during winter with 2.46${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of heavy metals(Pb, Cu, Mn, Ni) were 186.0 ng/㎥ in summer, 222.6 ng/㎥ in autumn, and 135.83 ng/㎥ in winter. Over the seasons inspected, the concentration of Mn was higher in coarse particles than fine particles and concentration of Ni was higher in fine particles than coarse particles. during yellow sand period, the concentration of TSP was increased about two times than that of other period. SO42-, Ca2+ concentrations were higher than other ionic components because of soil particles. The concentration of Ni showed 94.62ng/㎥ was increased about 4~5 times than other period. Principal component of the yellow sand, SO42-, Ca2+ could be discreased by rainfall and washout effect of atmospheric aerosol was higher in coarse particles than fine particles. Results from PCA(principal component analysis) showed that major pollutant was NaCl by seasalt particulate and (NH4)2SO4.

• Korean Journal of Materials Research
• /
• v.13 no.2
• /
• pp.115-119
• /
• 2003

The thick film type sensor having Pt/Na Super Ionic Conductor(NASICON) solid electrolyte/Pt/$Na_2$$SO_4$/Pt catalyst system for $SO_2$gas was fabricated by screen-print method. The phase of Na Super Ionic Conductor solid electrolyte sintered at different temperature of 1050, 1150,$ 1250^{\circ}C$ and for different time of 1.5, 2.5, 3.5 hr were investigated by XRD. The Electromotive Force variation of the sensor with $SO_2$concentrations and operating temperatures were investigated. The major phase of Na Super Ionic Conductor film sintered at 115$0^{\circ}C$ for 3.5 hr was sodium zirconium silicon phosphate($Na_3$Zr$_2$$Si_2$PO$_{12}$). The Nernst's slope of Na Super Ionic Conductor sensor for $SO_2$gas with the variation of concentration from 10 to 100 ppm was 167.14 ㎷/decade at the operating temperature of $500 ^{\circ}C$. The increase of oxygen partial pressure was not affected to the variation of Nernst's slope.e.

• Journal of environmental and Sanitary engineering
• /
• v.9 no.2
• /
• pp.24-31
• /
• 1994

Aerosol size distribution were determined in Seoul by Anderson sampler from October 1989 to September 1991 for the major ionic species(SO$_{4}$$^{2-}$, NO$_{3}$$^{-}$, Cl$^{-}$, Na$^{+}$, Na$^{+}$, K$^{+}$, Ca$^{2+}$ and Mg$^{2+}$) and TSP( Total Suspended Particles ). The seasonal variations in concentrations and size distribution have been investigated. The size distributions of TSP and each of ionic species were bimodal throughout the year. The size distribution of these ions were divided as follows; (1) fine- mode dominant for SO$_{4}$$^{2-}$ and N%'. (2) coarse- mode dominant for NO$_{3}$$^{-}$, Cl$^{-}$, Ca$^{2+}$ and Mg$^{2+}$. (3) both- mode dominant for TSP.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.4
• /
• pp.186-193
• /
• 2017

Microwave (MW) is an effective method for solubilizing organic solids because it has thermal, non-thermal and ionic conduction effects by dielectric heating and high energy efficiency. In this study, we evaluated the application of MW to the solubilization of cattle manure and investigated the solubilization ratio of cattle manure by solid concentration, MW power and target temperature. And $H_2SO_4$ and NaCl were added to investigated the effects on the MW-assisted solubilization. Also, we evaluated the solubilization efficiency by biochemical methane potential(BMP) test according to the solubilization conditions. Maximum SCOD increment per energy supply was 70.5 mg $SCOD_{increased}/kJ$ at 12% of the solid concentration, MW power of 800 W and the target temperature of $40^{\circ}C$. And SCOD concentration went up 153.2% compared to the initial concentration. In the MW-assisted solubilization with $H_2SO_4$ and NaCl as chemical catalysts, SCOD concentration was increased by 36% and 22.7%, respectively, compared to the result of MW. The methane production was increased by 13.3% and 11.3% with the addition of $H_2SO_4$ and NaCl. Therefore, MW is an effective method for solubilization of cattle manure, and it is necessary to use chemical catalysts to increase the solubilzation efficiency.

• Korean Journal of Food Science and Technology
• /
• v.15 no.4
• /
• pp.370-378
• /
• 1983

Changes of protein and amino acids composition in improvement-Meju inoculated with Aspergillus oryzae were emamined at various time intervals over 6-day test period. To investigate those changes systematically, Disc gel electrophoresis, gel fiteration and amino acid analyzer were used. Following results were obtained; 1. Nitrogen solubility of the soybean meal in $Na_{2}SO_{4},\;MgSO_{4},\;Na_{2}CO_{3},\;NaCl\;and\;Na_{2}HPO_{4}$ solutions of various concetrations were determinated. The salt soluble protein of soybean meal was highly dispersible on 0.4M $Na_{2}SO_{4}$ solution and the extractability of protein was 33%. 2. From the quantitative fractionation of soybean proteins, albumin content (46.0%) was highest followed by globulin (33.9%), glutelin (19.5%) and prolamin (2.4%). During Meju incubation period, albumin and prolamin increased gradually but glutelin decreased. Globulin content was not changed substantially. 3. When albumin was fractionated by Sephadex G-200, the following results were obtained. Soybean albumin showed fraction which was reduced to 3 fraction at 0-day of incubation. The number of fraction, however increased to 8 after 6-day of incubation. 4. Amino acids of albumin in soybean and Meju appeared to be 17 kinds. Glutamic acid and aspartic acid were the highest. In amino acid composition of cooked soybean albumin, arginine, aspartic acid, glutamic acid and glycine remained higher than those of Meju throughout incubation period. 5. The major fraction of albumins from soybean and Meju fractionated by Sephadex G-200 showed 17 kinds of amino acid. Aspartic acid and glutamic acid were the highest. During Meju incubation period, the change of amino acid composition was investigated; threonine, serine, lysine, histidine, alanine, isoleucine, leucine, phenylalanine and $NH_3$ was increased gradually, the others decreased. 6. According to the electrophoretic pattern, soybean protein showed 13 bands which decreased to 3-after cooking. During incubation, those bands increased gradually to 10 bands after 6-days.

• Korean Journal of Materials Research
• /
• v.13 no.8
• /
• pp.524-530
• /
• 2003

In order to prepare the uniform copper particles from copper sulfate solution by using hydrazine as a reduction agents, the reduction behavior of copper particles from copper sulfate was investigated in detail at room temperature by the observation of reaction products. The effects of $NH_4$OH and $Na_4$$P_2$$O_{7}$ on the formation of uniform copper particles were discussed. ($NHCu_3$)$_4$$SO_4$was completely formed at over pH 11 by adding $NH_4$OH in copper sulfate solution. The fine $Cu_2$O with the particle size of 50 nm was produced in the initial reduction process of (NH$Cu_3$)$_4$$SO_4$solution with $Na_4$$P_2$$O_{ 7}$ and then the Cu$_2$O was converted into copper particles by inserting additional hydrazine. When Cu(NH$_3$)$_4$SO$_4$solution with $Na_4$$P_2$$O_{ 7}$ was reduced at $80^{\circ}C$ by hydrazine, the highly dispersed copper particles with the particle size of about 0.8 $\mu\textrm{m}$ was obtained.

• Membrane Journal
• /
• v.18 no.2
• /
• pp.132-137
• /
• 2008

Nanofiltration membranes were prepared based on coating a sulfonated comb-like copolymer layer on top of a poly(vinylidene fluoride) (PVDF) support. The comb-like copolymer comprising poly(vinyl chloride) backbone and poly(styrene sulfonic acid) side chains, i.e. PVC-g-PSSA was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of PVC. The successful synthesis of graft copolymers were confirmed by nuclear magnetic resonance ($^1H$-NMR), FT-IR spectroscopy and wide angle X-ray scattering (WAXS). Composite nanofiltration membranes consisting PVC-g-PSSA as a top layer exhibited the increase of both rejections and solution flux with increasing PSSA concentration. This performance enhancement is presumably due to the increase of SO3H groups and membrane hydrophilicity. The rejections of composite membranes containing 71 wt% of PSSA were 88% for $Na_2SO_4$ and 33% for NaCl, and the solution flux were 26 and $34L/m^2h$, respectively, at 0.3 MPa pressure.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.4
• /
• pp.481-486
• /
• 1995

The salt stress at seedling stage of winter barley was examined in different concentrations of NaCl containing 1/2 Hoagland solution. Fresh weight of seedling at 30 days after seeding was highest at 25mM of NaCl concentration containing 1/2 Hoagland solution but if the NaCl concentration was more than 50mM it began to decrease seriously. Water content in plant was decreased according to increase of NaCl concentration in 1/2 Hoagland solution, so physiological mechanism of NaCl in barley was different from saline plant. Stoma number per cm$^2$ of first leaf was higher than that of control in case of stressed by NaCl but in that case the leaf length was decreased so the number of stoma per first leaf was slightly decreased. Chloroplast shape was not changed by 75mM of high NaCl contained 1/2 Hoagland solution but cell division at root growing point was inhibited by 75mM of NaCl. As the result of salt stress mitochondria was ruined in structure and irregular solid was found to be transfered from the cytoplasm to the cell wall in root growing point.

• Journal of Environmental Health Sciences
• /
• v.42 no.2
• /
• pp.112-117
• /
• 2016

Objectives: In this study, we investigated the biodegradation rates of 8 perfluorooctanesulfonate (PFOS) alternatives synthesized at the at Changwon National University in comparison to those of PFOS potassium salt and PFOS sodium salt. Methods: A biodegradability test was performed for 28 days with microorganisms cultured in the good laboratory practice laboratory at the Korea Environment Corporation following the OECD Guidelines for the testing of chemicals, Test No. 301 C Results: While $C_5H_8F_3SO_3K$, $C_8F_{17}SO_3K$ and $C_8F_{17}SO_3Na$ were not degraded after 28 days, the 3 alternatives were biodegraded at the rates of 31.4% for $C_8H_8F_9SO_3K$, 25.6% for $C_{10}H_8F_{13}SO_3K$, 23.6% for $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 15.5% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, 8.5% for $C_{17}F_9H_{25}S_2O_8Na_2$ and 4.8% for $C_6H_8F_5SO_3K$. When the concentration was the same(500 mg/L), $C_{23}F_{18}H_{28}S_2O_8Na_2$ had the lowest tension with 20.94 mN/m, which was followed by $C_{15}F_9H_{21}S_2O_8Na_2$ (23.36 mN/m), $C_{17}F_9H_{25}S_2O_8Na_2$ (27.31 mN/m), $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ (28.17 mN/m), $C_{10}H_8F_{13}SO_3K$ (29.77 mN/m) and $C_8H_8F_9SO_3K$ (33.89 mN/m). Having higher surface tension of 57.64 mN/m and 67.57 mN/m, respectively, than those of the two types of PFOS salts, $C_6H_8F_5SO_3K$ and $C_5H_8F_3SO_3K$ were found valueless as substitute for PFOS. Conclusion: The biodegradation test suggest that 6 compounds could be used as substitutes for PFOS. $C_{23}F_{18}H_{28}S_2O_8Na_2$ and $C_{15}F_9H_{21}S_2O_8Na_2$ were found to be the best substitutes based on biodegradation rate and surface tension, followed by $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_8H_8F_9SO_3K$ and $C_{10}H_8F_{13}SO_3K$. $C_{17}F_9H_{25}S_2O_8Na_2$ was found to have relatively low value as an alternative but it still had a potential to substitute the conventional PFOS.