• Fibers and Polymers
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• v.5 no.4
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• pp.303-308
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• 2004

A natural colorant was extracted from Cassia tara L. using buffer solutions (pH: 2-11) as extractants. The dyeing solution (Cassia tara L. extract) extracted using pH 9 buffer solution was found to give the highest K/S values of dyed fabrics. Cotton and silk fabrics were dyed with Cassia tara L. extract at $60^{\circ}C$ for 60 min with pre-treatment of various metal salts as mordants. It was found that Cassia tara L. extract was polygenetic dyestuffs and its major components were anthraquinones. Studies have been made on the effects of the kind of mordant on dyeing properties and colour fastnesses of cotton and silk fabrics. The K/S of cotton fabrics increased in the order of the dyeing using $FeSO_4 >CuSO_4> ZnSO_4> MnSO_4\cong Al_2(SO_4)_3 > NiSo_4 > none$, however, the K/S of silk fabrics increased in the order of the dyeing using $FeSO_4 > CuSO_4 > ZnSO_4\cong Al_2(SO_4)_3 > MnSO_4\cong NiSO_4 > none$. It was found that the K/S values of dyed fabrics were largely affected by the colour difference $(\DeltaE)$ between mordanted fabric and control fabric. However, they were not depended on the content of mordanted metal ion of the fabrics. Mordants $FeSO_4$ and CuSO_4$ for cotton fabric, $FeSO_4,\; CuSO_4,\; and\; Al_2(S0_4)_3$ for silk fabric were found to give good light fastness (rating 4).

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.420-425
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• 2011

In general, the decomposition of $CaSO_4$ formed by sulfation reaction in the in-furnace desulfurization process using limestone has strong effect on the desulfurization reaction under the oxy-fuel combustion condition. In this study, the conversion rates were measured and reaction rates were calculated in order to investigate the effects of the experimental variables such as temperature and the concentrations of $CO_2$, $O_2$, $SO_2$, on the $CaSO_4$ decomposition reaction using DTF (Drop Tube Furnace) in the desulfurization reaction. The conversion rate and the reaction rate of $CaSO_4$ decomposition reaction were increased with reaction temperature. $CO_2$ concentration has little effect on $CaSO_4$ decomposition reaction in the presence of $O_2$. Under the same experimental conditions, the decomposition rate of $CaSO_4$ was enhanced with the decreasing the $O_2$ concentration, but vice versa with the increasing of $SO_2$ concentration.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.127-132
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• 2010

We analyzed the effects of several process variables on the $SO_2$ removal and particle growth by the dielectric barrier discharge - photocatalysts hybrid process. In this process, $SO_2$ was converted into the ammonium sulfate ($(NH_4)_2SO_4$) particles. The size and crystallinity of ammonium sulfate particles were examined by using TEM and XRD analysis. The dielectric barrier discharge reactor consisted of two zones: the first is for plasma generation and the second is for ammonium sulfate particles formation and growth. The first zone of reactor was filled with glass beads as a dielectric material. To enhance $SO_2$ removal process, the $TiO_2$ photocatalysts were coated on glass beads by dip-coating method. As the voltage applied to the plasma reactor or the pulse frequency of applied voltage increases, the $SO_2$ removal efficiency increases. Also as the initial concentration of $SO_2$ decreases or as the residence time increases, the $SO_2$ removal efficiency increases. $(NH_4)_2SO_4$ particles continue to grow by particle coagulation and surface reaction, moving inside the reactor. Larger particles in site are produced according to the increase of residence time or $SO_2$ concentrations.

• Journal of the Korean Ceramic Society
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• v.44 no.9
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• pp.471-476
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• 2007

The hydration mechanism of the $3CaO{\cdot}Al_2O_3-CaSO_4{\cdot}2H_2O$ system in the presence of alkali sulfates has been investigated. The early hydration rate of $3CaO{\cdot}Al_2O_3$ was accelerated by the addition of $Na_2SO_4$ and $K_2SO_4$. This is closely related to the formation of syngenite $(CaSO_4{\cdot}K_2SO_4{\cdot}H_2O)$, and the U-phase added $K_2SO_4$ and $Na_SO_4$ in the $3CaO{\cdot}Al_2O_3-CaSO_4{\cdot}2H_2O$ system, respectively. The formation of the rigid syngenite and U-phase structure led to rapid setting and decreases the sulfate content in the liquid phase of the hydrating cement to the extent that it cannot adequately retard the hydration of $3CaO{\cdot}Al_2O_3$. In case of the alkali sulfate not added to the $3CaO{\cdot}Al_2O_3-CaSO_4{\cdot}2H_2O$ system, the ettringite was transformed to monosulfoaluminate immediately after the consumption of gypsum. However, when the alkali sulfates were added to this system, the ettringite did not transform to monosulfoaluminate immediately even though the gypsum was completely consumed. There was a stagnation period to transform to the monosufoaluminate after the consumption of gypsum because the syngenite and U-phase remained as the sulfate source.

• Analytical Science and Technology
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• v.20 no.5
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• pp.383-392
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• 2007

The water soluble components were analyzed in the $PM_{2.5}$ fine particles collected at the 1100 site of Mt. Halla for the spring seasons between 1998 and 2004. The $PM_{2.5}$ mass concentrations were within $13.4{\pm}9.6{\sim}21.7{\pm}20.0{\mu}g/m^3$, and the concentrations of ionic components were in the order of nss-$SO{_4}^{2-}$ > $NH{_4}{^+}$ > $NO{_3}{^-}$ > $Ca^{2+}$ > $K^+$ > $Na^+$ > $Cl^-$ > $Mg^{2+}$, in which the concentration of nss-$SO{_4}^{2-}$($3.41{\pm}2.42{\mu}g/m^3$) was the highest. The concentrations of $NH{_4}{^+}$, $SO{_4}^{2-}$, and $NO{_3}{^-}$, the secondary pollutants, were respectively 0.60~1.50, 2.86~4.42, and $0.24{\sim}1.57{\mu}g/m^3$, which had occupied 88 % of the total ionic components, on the other hand, the concentrations of marine species were less than 5 %. The nss-$SO{_4}^{2-}$ showed the high correlation with $NH{_4}{^+}$, $K^+$, so that $NH{_4}{^+}$ and nss-$SO{_4}^{2-}$ might exist in the form of $(NH_4)_3H(SO_4)_2$ and $(NH_4)_2SO_4$ in fine particles. From the backward trajectory analysis, in case of high concentrations of $NH{_4}{^+}$ and nss-$SO{_4}^{2-}$ simultaneously, the air masses were originated and stagnated at the east region of China for a while, then moved into the atmosphere of Jeju. However, in case of $NO{_3}{^-}$ and nss-$Ca^{2+}$, the air masses originated at China and Siberia were moved into Jeju via the eastern China.

• Journal of the Korean Ceramic Society
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• v.20 no.4
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• pp.297-304
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• 1983

In this study a Comparative investigation of the effect of $K_2SO_4$ and $CaSO_4$ on the formation of calcium silicate was made. $K_2SO_4$ had little effect on C3S formation. More than 4.0wt% of CaSO4 hindered the reaction of $C_2S$ and CaO so $C_3S$ formation was restrained by forming the reaction rim around $C_2S$ Particles. And activation energy for $C_3S$ formation was calculated around to be 40kcal/mol irespective of the amount of $K_2SO_4$.

• Journal of Sensor Science and Technology
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• v.5 no.4
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• pp.25-34
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• 1996

A SOx sensor using NASICON electrolyte was developed for monitoring of air pollution. The following galvanic cell with $Na_{2}SiO_{3}(Pt)$ reference electrode was assembled : Pt | $Na_{2}SiO_{3}$ | NASICON | $Na_{2}SO_{4}$ | Pt, $SO_{2}$, air $Na_{2}SO_{4}$ was used as an indicator electrode to protect NASICON electrolytes from chemical reaction with $SO_{2}$. The EMFs were measured after injecting $SO_{2}$ in the initial concentrations range of $5{\sim}95ppm$ at $400{\sim}550^{\circ}C$. The measured and calculated potentials were in good agreement above $500^{\circ}C$. However, the cells were unstable below $500^{\circ}C$, most likely due to incomplete attainment of chemical equilibrium. Response time was within 10 min. Based on the stability and response time of this cell, the NASICON solid electrolyte with $Na_{2}SiO_{3}(Pt)$ as the reference electrode and $Na_{2}SO_{4}$ (Pt)as the indicator electrode showed the possibility of a reliable, inexpensive commercial solid-state SOx sensor.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.247-251
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• 1989

Effects of mineral salts on sisomicin fermentation were investigated. The optimal concentration of CoCl$_2$for accomplishing a high antibiotic yield was found to be 16.8 $\mu$M at which it could function as a cofactor. At this level the other mineral salts tested had no effect. On the other hand, at much higher concentration levels (above 1 mM), four mineral salts such as ZnSO$_4$, KH$_2$PO$_4$, FeSO$_4$and MgSO$_4$were used in order to liberate the intracellular sisomicin out-side the cells, because the sisomicin accumulated mostly in cells and it was supposed to limit the improvement of antibiotic yield. ZnSO$_4$and KH$_2$PO$_4$had no effect at all, and FeSO$_4$brought about some improvement. However, by keeping the concentration of MgSO$_4$to be 25 mM or higher in culture broths, the antibiotic yield could be improved by more than 100%, partially due to the enhanced liberation of the intracellular antibiotic.

• Journal of the Korean Ceramic Society
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• v.30 no.1
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• pp.7-16
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• 1993

Effect of sulfate on the reactionof C3S formation in presence of clinker melt and its appearance in clinker were investigated, using (NH4)2SO4 and CaSO4 as sulfate sources. When (NH4)2SO4 and CaSO4 were added, both showed the similar results, 1.0wt% of sulfate could promoted the reaction of C3S formation, however for its content of more than 2.0wt%, the formation of C3S was prevented. Residual limit of sulfate to C3S formation is about 1.4wt%. Appearances of sulfate were C4A3l and CaSO4 in interstitial phase. For the addition of (NH4)2SO4 or CaSO4 of 20wt%~4.0wt%, C3S grains showed the hypertrophic growth. We might consider that, because sulfate reduced the surface tension and viscosity of the clinker melt, C3S crystals were precipitated below 140$0^{\circ}C$, and the crystlas of C3S were coalesced and linked in the same crystallographical direction with increasing temperature becuase of their rapid growth rate.

• Cement
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• s.51
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• pp.20-30
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• 1973

1) electron-microprobe를 응용하여 $CaO-SiO_2-Al_2O_3$ 계에서 생성한 $C_2S$, $C_3S$ 에 존재하는 sulfate의 solid, solution을 정량적으로 구할 수 있었으며 이 결과로 $C_2S$ 에 $Al_2O_3$, $SO_3$ 등이 solid soln 등으로 침적되고 이들이 $C_3S$의 생성을 억제한다는 mechanism이 확인되었다. 2) phase equilibrium(상평형)에 의하면 $Na_2SO_4$, $K_2SO_4$는 mineralizer로서 작용하며 $C_3S$ 의 생성을 돕는다. 그러나 $K_2SO_4$ 와 $Al_2SO_3$ 가 결합상태로 존재할 경우는 1,400 $^{\circ}C$에서 광범위한 liquid를 생성하며 quenching하면 glass질과 $\beta-C_2S$ 만이 얻어지고 $C_3S$ 는 생성되지 않는다. 또 이를 1,250 $^{\circ}C$ 까지 서냉하면 $C_2S$ 와 Ca, K, Al, S, 등을 함유한 새로운 물질이 생성된다. 3) $CaO-SiO_2-Al_2O_3-Fe_2O_3$ 계에서 $C_3S$ 의 생성에 미치는 $Na_2SO_4$, $K_2SO_4$ 의 영향을 실험실적으로 검토한 결과 complex interaction이 확인되었으며 $Na_2SO_4$ 는 어떤 경우에는 mineralizing effect를 상실한다는 재미 있는 사실이 발견되었다.