• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.209-212
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• 2006

Until now, sulfate attack is not completely understood. The purpose of this study is to provide a fundamental data to understand deterioration mechanism by sulfate attack. Chemical processes for products formed by sulfate attack were explained in this study. ASTM C1012 test and microstructural observations such as XRD and BSE analysis were carried out to manifest behavior and role of the products formed during sulfate attack. Regarding the dominant causes of sulfate attack, the main deterioration modes could be divided into 3 types; (1) expansive type, (2) onion-peeling type, and (3) acidic type.

• Computers and Concrete
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• v.4 no.2
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• pp.157-166
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• 2007

The paper considers a theoretical model to study sulfate ion diffusion in saturated porous media - cement based mineral composites, accounting for simultaneous effects, such as filling micro-capillaries (pores) with ions and chemical products and liquid push out of them. Pore volume change and its effect on the distribution of ion concentration within the specimen are investigated. Relations for the distribution of the capillary relative radius and volume within the composite under consideration are found. The numerical algorithm used is further completed to consider capillary size change and the effects accompanying sulfate ion diffusion. Ion distribution within the cross section and volume of specimens fabricated from mineral composites is numerically studied, accounting for the change of material capillary size and volume. Characteristic cases of 2D and 3D diffusion are analyzed. The results found can be used to both assess the sulfate corrosion in saturated systems and predict changes occurring in the pore structure of the composite as a result of sulfate ion diffusion.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1097-1100
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• 2003

This paper describes the sulfate resistance of cement pastes and mortar with or without ground granulated blast furnace slag (GGBS). Sulfate attack was performed on the cement pastes and mortar, which had been prepared by using a water-binder ratio of 0.45. Variables were the fineness levels of GGBS and the concentrations of two sulfate solution. In this present study, compressive strength and length change were carried out to evaluate the sulfate resistance of GGBS with various fineness levels. From the test results, it can be concluded that the deterioration modes of cement matrix with GGBS were dependent on the exposure solutions. Moreover, the influence of fineness levels of GGBS on the sulfate resistance was somewhat little because of a relative short exposure period.

• Journal of the Korean Home Economics Association
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• v.42 no.8
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• pp.113-121
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• 2004

This study used cupric sulfate as a bum-out agent. The concentration of cupric sulfate, temperature and time were varied with glycerin included or excluded on the properties of polyester ground fabrics. The results are as follows. The effect of carbonization with glycerin included was decreased, but removal of carbide with glycerin included was easier than that with glycerin excluded. The white index and tensile strength of polyester ground fabrics were decreased as the processing concentration, temperature and time increased. The shrinkage was increased as the processing concentration, temperature and time increased. The optimum conditions with cupric sulfate as the bum-out agent was 5％ concentration, 140$^{\circ}C$, 3min., and 3kgf/cm$^2$ and with cupric sulfate added to glycerin was 5％ concentration, 150$^{\circ}C$, 5min., and 3kgf/cm$^2$.

• Journal of Microbiology
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• v.43 no.2
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• pp.166-171
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• 2005

In order to determine the effects of sulfate concentration on the anaerobic dechlorination of polychlorinated biphenyls, sediments spiked with Aroclor 1242 were made into slurries using media which had various sulfate concentrations ranging from 3 to 23 mM. The time course of dechlorination clearly demonstrated that dechlorination was inhibited at high concentration of sulfate due to less dechlori-nation of meta-substituted congeners. When the dechlorination patterns were analyzed by the calculation of Euclidean distance, the dechlorination pathway in the 3 mM sulfate samples was found to be different from that observed in the 13 mM samples, although the extent of dechlorination in these two samples was similar. It is possible that the dechlorination in the high sulfate concentration samples is inhibited by the suppression of growth of methanogen, which have been shown to be meta-dechlorinating microorganisms.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.45-54
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• 1999

The purpose of this study was to examine the increased bone loss caused by ovariectomy through monitoring the concentrations of the collagen and the pyridinoline crosslinks of collagen. The ovariectomized rats treated for 8 weeks, were divided at random into two or three groups of 10. Ovariectomies were carried out from the saline-treated group (Ovx), the estrogentreated group (Ovx+ES) and chondroitin sulfate-treated group (Ovx+CS). Sham operations were performed on the sham-operated group (Sham). Ovx+ES and Ovx+CS groups showed the remarkably increased collagen and pyridinoline amount in the bone and cartilage compared to Ovx group. And as the result of the measurement of SOD, Catalase and GPx which are antioxidant enzyme, SOD and Catalase activities in Ovx group were much higher than in Sham group. But they were significantly decreased in Ovx+CS group. Based on these results, it is supposed that estrogen and condroitin sulfate can enhance collagen synthesis and affect the pyridinoline formation in collagen fibrils through stimulating lysyl oxidase activity. And it is also thought that chondroitin sulfate can inhibit aging by reducing antioxidant enzyme.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.490-495
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• 1996

The anti-compliment activity of hemolytic complementary assay(TCH50) of rhamnan sulfate fraction obtained from water extracts of Monostroma nitidum was investigated Rhamnan sulfate Fraction, F-4-3 fraction appeared relatively strong anti-complementary activity which decreased TCH50 over 60% than that comparison with control, and F-4-3 considerably inhibited ACH50. F-4-3 inhibited formation of the classical pathway C3 convertase or C4 cleavage. The results also indicate the mode of complement activation by F-4-3 fraction shows not only the classical pathway but also the alternative pathway.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.33-40
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• 2004

The eliminating of organic compound is essential process of the recovery of zinc sulfate from zinc sulfate waste water contained organic compound. The ozone oxidation and adsorption treatment is good for eliminating of organic compound in waste water. The zinc oxide treated an excess of sulfuric acid for zinc sulfate. We got zinc sulfate 740g from water 1kg.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.153-171
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• 1999

The purpose of this study was to evaluate the effect of modified calcium sulfate paste on periodontal regeneration. l-wall intrabony defect(mesio-distal width: 4mm, depth: 4mm) was surgically created on the distal side of P2 and mesial side of p4 in four dogs. The control group(GFS) was treated with conventional flap operation alone, and the experimental group(CS) was treated with conventional flap operation with modified calcium sulfate paste application. Both control and experimental groups were sacrificed after 8weeks of healing period, The results of histological and histometric observations were as follows. 1. The length of the junctional epithelium was 0.41${\pm}$0.01mm in the control groups, 0.47${\pm}$0.01mm in the experimental group. 2. The connective tissue attachment was 0.28${\pm}$0.02mm(6.15${\pm}$0.28%) in the control group, 0.18${\pm}$0.01mm(3.41${\pm}$0.14%) in the experimental group. The control group showed more connective tissue attachment. 3. The new cementum formation was 3.80${\pm}$0.06mm(84.80${\pm}$0.33%) in the control group, 4.49${\pm}$0.06mm(87.57${\pm}$0.15%) in the experimental group. Both groups showed a lot of new cementum formation. 4. The new bone formation was 1.43${\pm}$0.03mm(32.37%) in the control group, 2.04${\pm}$O.09mm(40.94%) in the experimental group. 5. The inflamatory cells were observed partially around resorbed calcium sulfate in the connective tissue of the experimental group. 6. Partially resorbed calcium sulfate were found within the connective tissue, around alveolar bone, and in the newly formed alveolar bone, On the basis of these results, newly formed calcium sulfate paste enhanced new bone formation and new cementum formation. The resorption rate of calcium sulfate seems to be controlled by the add-in compounds. Thus research about biocompatibility and adequate resorptionrate is required to develop a improved material.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.63-69
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• 2015

It has been well known that concrete structures exposed to chloride and sulfate attack environments lead to significant deterioration in their durability due to chloride ion and sulfate ion attack. The purpose of this experimental research is to evaluate the resistance against chloride ion and sulfate attack of the cementless concrete replacing the cement with ground granulated blast furnace slag. For this purpose, the cementless concrete specimens were made for water-binder ratios of 40%, 45%, and 50%, respectively and then this specimens were cured in the water of $20{\pm}3^{\circ}C$ and immersed in fresh water, 10% sodium sulfate solution for 28 and 91 days, respectively. To evaluate the resistance to chloride ion and sulfate attack for the cementless concrete specimens, the diffusion coefficient for chloride ion and compressive strength ratio, mass change ratio, and length change ratio were measured according to the NT BUILD 492 and JSTM C 7401, respectively. It was observed from the test results that the resistance against chloride ion and sulfate attack of the cemetntless concrete were comparatively largely increased than those of OPC concrete with decreasing water-binder ratio.