• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.55-61
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• 1998

This experiment was conducted to evaluate the effects of sulfate ion concentration in nutrient solution on the growth and qualify of Mongolian wormwood (Artemisia mongolica var. tenuifolia). Sulfate ion concentration was treated 0, 0.5, 1, 2 and 3mM using the modified nutrient solution composition for herb plants developed by European Vegetable R & D Center in Belgium. The growth of Mongolian wormwood was good at 3mM treatment and dry weight was best at 3mM treatment, Chlorophyll content increased with sulfate ion concentration. Mineral content did not show any significant difference among treatments. But Ca content in tissue markedly decreased at 3mM treatment. Sulfate ion uptake increased in proportion to sulfate ion concentration in nutreint solution, the higher sulfate ion concentration, the more uptake of sulfate ion by plant. At 1mM sulfate ion treatment, essential oil content was best, but the higher sulfate ion concentration resulted in decrease of essential oil content.

• 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$^2$.

• Computers and Concrete
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• v.10 no.1
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• pp.79-93
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• 2012

This paper estimates theoretically the diffusion-reaction behaviour of sulfate ion in concrete caused by environmental sulfate attack. Based on Fick's second law and chemical reaction kinetics, a nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete, in which the variable diffusion coefficient and the chemical reactions depleting sulfate ion concentration in concrete are considered, is proposed. The finite difference method is utilized to solve the diffusion-reaction equation of sulfate ion in concrete, and then it is used to simulate the diffusion-reaction process and the concentration distribution of sulfate ion in concrete. Afterwards, the experiments for measuring the sulfate ion concentration in concrete are carried out by using EDTA method to verify the proposal model, and results show that the proposed model is basically in agreement with the experimental results. Finally, Numerical example has been completed to investigate the diffusion-reaction behavior of sulfate ion in the concrete plate specimen immersed into sulfate solution.

• 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 Environmental Health Sciences
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• v.22 no.3
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• pp.64-71
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• 1996

Measurement of concentration and size distribution of TSP, ammonium, nitrate and sulfate were made from Mar., 1991. to June., 1992 in Seoul. The seasonal variation of concentration and size distribution of aerosols has been investiated. Aerosol were collected and size frationated by Andersen air sampler. Size classified samples were extrated with deionized water and analyzed for ammonium, nitrate and sulfate by ion chromatography. As the results of measurement, the average of concentration and MMAD(mass median aerodynamic diameter) were $118.58 \mu g/m^3$, and $2.77 \mu m$ for TSP, $1.92 \mu g/m^3$ and $1.35 \mu m$ for ammonium, $1.34 \mu g/m^3$ and $1.58 \mu m$ for nitrate, $8.52 \mu g/m^3$ and $2.15 \mu m$ for sulfate. The Seasonal variation of concentration and size distribution was observed for ammonium, nitrate and sulfate. The concentration peak of TSP was observed in coarse particles in spring and observed in fine particles in winter. The concentration's distribution of TSP, ammonium, nitrate and sulfate was observed bimodal type during all season.

• Computers and Concrete
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• v.33 no.1
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• pp.1-11
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• 2024

Aggressive environmental conditions, and especially the acidic effects of sulfate ion penetration, have reduced the lifetime of concrete structures in some areas, especially coastal and marine areas. In this research, at first, samples made of type II and V cement were kept in a solution of magnesium sulfate (MgSO₄) for a period of 90 and 180 days, the change of appearance. Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD), were used to analyze the microstructure and the complex mineral composition of the concrete after exposure to corrosive environments. Then solving the differential equation governing the sulfate ion penetration, which is based on the second Fick law, it has been tried to determine the concentration of sulfate ions inside the concrete. In the following, an attempt has been made to improve the prediction of sulfate ion concentration in concrete by using Crank's penetration equation. At the same time, the coefficient in the Crank's solution have been optimized by using the Particle Swarm Optimization (PSO algorithm). The comparison between the results shows that the values obtained from Crank's relation are closer to the experimental results than the equation obtained from Fick's second law and shows a more accurate prediction.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.877-891
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• 1998

This study was designed to observe the effects of various concentration of polyacrylic acid containing different concentration of sulfate ion on the crystal formation on the enamel surface. Experimental crystal growth solutions were made of $10\%,\;20\%,\;30\%\;and\;40\%$ polyacrylic acid(molecular weight,5,000) solutions which containing 0.1M, 0.2M, 0.3M, 0.5M, and 1.0M sulfate ion respectively. The extracted human first bicuspid enamel surface was contacted for n seconds with these solutions, washed for 15 seconds, dried, and then the crystal topography on the enamel surface was observed under the scanning electron microscope. The crystal topography were evaluated on the SEM photographs by degree of crystal coverage, crystal length, and consistency of crystal morphology, and conclusions were as the follows. 1. Polyacrylic acid solution etched slightly the enamel surface, and the difference of etching effect by its concentration was not observed. 2. The effect of concentration of polyacrylic acid on the crystal formation was less, especially that of $20\%\~40\%$ polyacrylic acid was almost not different. 3. Concentration of the sulfate ion was a determinant factor in precipitating crystals on the enamel. The experimental crystal growth solutions containing 0.1 M sulfate ion did not make crystal formation but those containing over 0.2 M sulfate ion did. 4. The degree of crystal coverage showed a tendency to increase and then decrease according to the concentration of sulfate ion in the $20\%-40\%$ polyacrylic acid. The experimental solutions containing 0.5 M sulfate ion showed the peak of degree of crystal coverage. 5. The crystal length showed a tendency to decrease by increment of sulfate ion in the polyacrylic acid solution. 6. There was a tendency to increase the frequency of random arragement of short crystals when increasing the concentration of sulfate ion in the polyacrylic acid solution. The lower concentration of sulfate ion in the polyacrylic acid solutions tended to make spherulitic arrangement of crystals, the higher concentration of sulfate ion, the more random arrangement of crystals. The experimental solutions containing 0.5M sulfate ion showed more spherulitic arrangement than random arrangement of crystals. 7. The best one of these experimental crystal growth solutions was $30\%$ polyacrylic acid solution containing 0.5M sulfate ion.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.220-228
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• 2010

This study examines the scouring effect of pectinase on ramie fabric and influence of sodium sulfate as an activator for pectinase. The scouring effects were measured by the weight loss and pectin contents. SEM, weight loss, stiffness, moisture regain and dye ability of ramie fabric teated with pectinase/sodium sulfate were also measured. When ramie fabrics were desized with $\alpha$-amylase, the optimum conditions were pH 6.5 at $60^{\circ}C$ for 80 min with 1%(o.w.f) $\alpha$-amylase concentration. When ramie fabrics were scoured with pectinase, the optimum conditions were pH 8.5 at $55^{\circ}C$ for 30 min with 10%(o.w.f) pectinase concentration. Addition of sodium sulfate improved enzyme activity significantly, which increased proportionally with increasing sodium sulfate concentration. When 50 g/l of sodium sulfate was added, the surface became cleaner compared to the enzyme treatment without salt: weight and tensile loss, moisture regain and dyeability of the treated fabrics increased, while pectin contents and stiffness decreased. Therfore, sodium sulfate was effective activator for the pectinase treatment of flax fiber.

• Geomechanics and Engineering
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• v.10 no.6
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• pp.807-826
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• 2016

In this study, aiming to investigate the effects of sulfate attack on cement stabilized highly plastic clay; an experimental study was carried out considering the effects of cement type, sulfate type and its concentration, cement content and curing period. Unconfined compressive strength and chloride-ion penetration tests were performed to obtain strength and permeability characteristics of specimens cured under different conditions. Test results were evaluated along with microstructural investigations including SEM and EDS analyses. Results revealed that use of sulfate resistance cement instead of normal portland cement is more plausible for soils under the threat of sulfate attack. Besides, it was verified that sulfate concentration is responsible for strength loss and permeability increase in cement stabilized montmorillonite. Finally, empirical equations were proposed to estimate the unconfined compressive strength of cement stabilized montmorillonite, which was exposed to sulfate attack for 28 days.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.1
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• pp.131-142
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• 2004

When the cotton/polyester fiber mixed fabrics were treated with ferrous sulfate and oxalic acid for burn out finishing, it was examined how the effects of process conditions as concentration of burn out agents, temperature, time and pressure act onto the properties of polyester ground fabrics. The results are as follows. The effect of burn out finishing by pressure was greated in 3 kgf/$\textrm{cm}^2$. The properties as white index and tensile strength of polyester ground fabrics were decreased according as processing concentration, temperature time increases. The shrinkage was increased according as processing concentration, temperature time increases. The optimum condition of burn out agents to ferrous sulfate was 30% concentration, 150$^{\circ}C$, 1 min, 3 kgf/$\textrm{cm}^2$ and to oxalic acid was 10% concentration, 110$^{\circ}C$, 1min, 3 kgf/$\textrm{cm}^2$. And the optimum of ferrous sulfate and oxalic acid used in combination was 10% ferrous sulfate and 7% oxalic acid, 110$^{\circ}C$, 1 min., 3 kgf/$\textrm{cm}^2$.