• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• Asian Journal of Atmospheric Environment
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• v.2 no.2
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• pp.102-108
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• 2008

In China, energy and environmental problems are becoming serious owing to rapid economic development. Coal is the most problematic energy source because it causes indoor and outdoor air pollution, acid rain, and global warming. One type of clean coal technology that has been developed is the coal-biomass briquette (or bio-briquette, BB) technique. BBs, which are produced from pulverized coal, biomass (typically, agricultural waste), and a sulfur fixation agent (slaked lime, $Ca(OH)_2$) under high pressure without any binder, have a high sulfur-fixation effect. In addition, BB combustion ash, that is, the waste material, can be used as a neutralization agent for acidic soil because of its high alkalinity, which originates from the added slaked lime. In this study, we evaluated the suitability of alternative biomass sources, namely, aquatic plants, as a BB constituent from the perspective of their use as a source of energy. We selected three types of aquatic plants for use in BB preparation and compared the fuel, handling, and environmental characteristics of the new BBs with those of conventional BBs. Our results showed that air-dried aquatic plants had a higher calorific value, which was in proportion to their carbon content, than agricultural waste biomass; the compressive strength of the new BBs, which depends on the lignin content of the biomass, was high enough to bear long-range intracontinental transport in China; and the new BBs had the same emission control capacity as the conventional BBs.

• Resources Recycling
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• v.7 no.4
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• pp.64-75
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• 1998

The purpose of this study is to produce high putity composite powder composed of Fe-oxide, Mn-oxide and Mn-ferrite having superior homogencity in composition and particle size distribution by co-roasting process. Binary component metal (Fe, Mn) chloride solutions were produced by dissolving mill scale and ferro-mangancse alloy in hydrochloric acid. These chloride solutions contained the impurities such as SiO$_{2}$, P, Al, Ca and Na, which were originated from the Fe/Mn source materials. The neutralization and polymeric coagulant method were adoped to refine the hydrochloric liquor. When pH is far below the isoelectric point (pH 2-3), the SiO$_{2}$ was the most effectively reduced element, while other impurities remained unchanged. By increasing pH above 3, most of the impurities could be reduced effectively due to the coprecipitation reaction. The polymeric coagulants such as poly vinyl alcohol, resin amine and ammonium molybdate were found to have no effect on the spray roaster designed by the authors. The produced oxide powders were confirmed to be mixtures of Fe-oxide, Mn-oxide and mn-ferrite. the powders were homogeneously mixed and the particle size increased sleeply with increasing co-roasting temperature.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.2
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• pp.104-108
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• 2015

Human serum albumin (HSA) has potential for diagnosis and therapy in clinical setting. The purpose of experiments was to develop and evaluate $^{68}Ga$-HSA as a PET agent for diagnosis of acute inflammation. NOTA-HSA was synthesized by conjugating 2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid to HSA in 0.1 M sodium carbonate buffer (pH 9.5) and then purified using a PD-10 size-exclusion column. NOTA-HSA was labeled with $^{68}Ga$ at room temperature for 10 min, and 8.4% sodium hydrogen carbonate buffer was added for neutralization. $^{68}Ga$-NOTA-HSA was purified using alumina N plus light cartridge and $0.22{\mu}m$ syringe filter. Labeling efficiency and radiochemical purity were determined by ITLC-SG with 0.1 M citric acid. Biodistribution study was performed in a male BALB/c mice model of Carrageenan-induced acute inflammation. Animal PET study was performed in acute inflammation mice model after tail vein injection of $^{68}Ga$-HSA. This radiotracer showed high labeling efficiency (>99%) around pH 7. Biodistribution study showed higher inflamed footpad uptake than control footpad uptake. Animal PET study revealed 2 times higher uptake on inflamed footpad compared to control footpad. In these experiments, we developed $^{68}Ga$-HSA for acute inflammation PET imaging and evaluated it in a mouse disease model. The results demonstrated that $^{68}Ga$-HSA has potential as a PET imaging agent for diagnosis of acute inflammation.

• Tribology and Lubricants
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• v.31 no.6
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• pp.251-257
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• 2015

Heavy oil production is receiving significant attention because of increased demands for thermal power generation systems of the diesel engine and boilers. However, asphaltene, which is a heavy oil components (6-8 wt%), reduces the heat efficiency of the fuels owing to its agglomerated sludge of asphaltene during the burning process. Therefore, for hassle-free operation, we should develop asphaltene dispersants to suppress the formation of the sludge. We prepare variable salt-type polymeric dispersants using poly(isobutenyl succinic anhydride) and poly(amine) through both condensation esterification and acid-base neutralization reactions, which we subsequently evaluate for dispersing performance, using Turbiscan measurement. Total acid number (TAN) and total base number (TBN) of 75Lec-25SynDis.2 composed of lecithin and the prepared polymeric salt having the ratio of 3 : 1 are 18.9 and 33.7 mg KOH/g, respectively, which are comparable to those of the commercial dispersants (15.8 and 26.5 mg KOH/g). We determine the initial turbidity observed for 15 min of the polymeric dispersant was determined with transmittance (%), which can be calculated to separability number (SN). The SN value of 75Lec-25SynDis.2 is close to zero, which is superior to that of commercial dispersants and lecithin (0.015 and 0.017).

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.215-221
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• 2005

Numerous abandoned or closed mines are present in the steep mountain valleys in Korea due to the depression of the mining industry since the late 1980s. From the mines, enormous amounts of wastes were dumped on the slopes causing sedimentation and acid mine drainage to be discharged directly into streams causing detrimental effects on surrounding environment. Objective of this research was to evaluate the feasibility of the lime cake by-product from the soda ash production (Solvay process) to neutralize the pyrophyllite mine wastes, which have discharged the acid drainage to soil and stream in the watershed. The pH of mine wastes was strongly acidic at pH 3.67 containing over 16% of $Al_2O_3$ and 11% of $Fe_2O_3$. Whereas the lime cake by-product was strongly basic at pH 9.97 due to high contents of CaO, MgO and $CaCl_2$ as major components. Column experiments were conducted to test the neutralizing capacity of the lime cake by-product for the acidic pyrophyllite mine wastes. The column packed with the wastes (control) was treated with the lime cake by-product, calcium carbonate, the dressing soil or combination. The distilled water was eluted statically through the column and the leachate was collected for the chemical analyses. Treatments of the mine wastes with the lime cake by-product (or calcium carbonate) as mixtures increased pH of the leachate from $3.5{\sim}4.0\;to\;7{\sim}8$. Concentrations of Fe and Al in the leachate were also decreased below 1.0 mg $L^{-1}$. A Similar result was observed at the combined treatments of the mine waste, the lime by-product (or calcium carbonate) and the dressing soil. The results indicated that the lime cake by-product could sufficiently neutralize the acid drainage from the pyrophyllite mine wastes without dressing soils.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.487-498
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• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.49-54
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• 2007

The issue of acid precipitation and related environmental problems in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater in Korea, its chemical properties during cultivation season from April to October in 2005 were investigated at Taean. Also, to estimate the contribution of ions on acidity, ion composition characteristics and neutralization effects by cations were determined. The electrical conductivity balance between measured and estimated values showed a high correlation. Rainwater was highly distributed in the range of pH $4.5{\sim}5.0$. The acidity of rainwater was relatively low during the month of June compared with other monitored periods. $Na^+$ was the main cation, followed by $H^+>Ca^{2+}>NH_4^+>K^+>Mg^{2+}$. Among these ions, $Na^+,\;NH_4^+,\;Ca^{2+}$ and $H^+$ comprised over 94% of the total cations. Rainwater anion composition was more than 80% with $SO_4^{2-}$ and $NO_3^-$. In rainwater samples, $NH_4^+$ and $Ca^{2+}$ contributed greatly to neutralizing the rain acidity. The sulfate content decreased until September, and sea salt derivatives were higher in May and October than during other monitored periods. Also, 78% of the soluble sulfate in rainwater was nss-$SO_4^{2-}$ (non-sea salt sulfate).

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.56-63
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• 2016

This experiment was compared and analyzed between the original surface paint through chloride penetration, neutralization, freeze-thaw and chemical corrosion resistance measuring internal structure and volume of voids in order to evaluate the effect of increase in durability of the newly modeled nano synthesized polymer paint painted on concrete surface which results improvement on air permeability to increase the durability of concrete structures. The test result of measuring volume of void and inner structure, concrete, spreaded with nano synthesized polymer paint, showed decreasing trend of pore volume in the range of less than $0.1{\mu}m$ and more than $0.3{\mu}m$. Also, using an electron microscope inside showed tightness of hydration texture. Chloride penetration depth of concrete, painted with nano synthesized polymer paint, was decreased more than 92% compared to non-painted concrete and 70% with water-based epoxy painted concrete. Especially, chemical corrosion resistance test set with aqueous solution of 5% sulfuric acid, non-painted concrete and water-based epoxy painted concrete showed weight loss of 4% after dipping for 12 days. On the other hand, concrete painted with nano synthesized polymer paint showed 1.7% weight loss under the same condition. Also, it showed great result of appearance under the criteria of Tsivilis et al.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.165-173
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• 2019

Hydrazine[$N_2H_4$] is a typical propellant for a rocket fuel in the field of aerospace. Since it is very toxic and harmful to the environment, various environmentally-friendly propellants have been developed. In this study, relatively a safe propellant, hydroxylammonium nitrate[$NH_3OHNO_3$], was prepared via a neutralization reaction of hydroxylamine[$NH_2OH$] and nitric acid[$HNO_3$]. FT-IR was used to analyze the chemical composition, chemical structure and functional groups of HAN. Thermogravimetric analysis showed the decomposition temperature of HAN. Ion chromatography was also used to evaluate the content of nitrate ions. It was proved that the peaks of FT-IR at $3161cm^{-1}$ and $1324cm^{-1}$ indicates the functionalities of N-H and N-O present in HAN. The decomposition temperature of HAN synthesized at pH 5 to 7 was $120-140^{\circ}C$, and pH 8 resulted in higher decomposition temperature than $140^{\circ}C$. Meanwhile, the sample obtained from pH 6-7 showed the concentration of nitric acid ion with 70%.