• 한국분무공학회지
• /
• 제20권1호
• /
• pp.20-27
• /
• 2015

Urea-SCR which is one of the aftertreatment technologies for reducing the NOx emission is widely used. An experimental study was performed to investigate urea decomposition under various thermo-fluid conditions, with different temperatures and velocities of inflow gas, and urea solution quantities. 40 wt. % aqueous urea solutions were used in this study. The inflow gas conditions were similar to the exhaust conditions of a large marine engine. The spray performance of urea solution injector was identical under all experimental conditions. The conversion efficiency of $NH_3$ was larger than that of HNCO under all experimental conditions, unlike for the theoretical thermolysis reaction.

• 상하수도학회지
• /
• 제35권1호
• /
• pp.27-37
• /
• 2021

Tetracycline is one of the most commonly used as antibiotics for the livestock industry and it is still widely used nowadays. Tetracycline and its metabolites are excreted with excrement, which is difficult to completely removed with conventional sewage treatment, therefore it is apprehended that the tetracycline-resistant bacteria occurs. In this study, the oxidant named ferrate(VI) was used to degrade the tetracycline and investigate the reaction between ferrate(VI) and tetracycline under various aqueous conditions. The highest degradation efficiency of tetracycline occurred in basic condition (pH 10.1 ± 0.1) because of the pKa values of tetracycline and ferrate(VI). The results also showed the effect of water temperature on the degradation of tetracycline was not significant. In addition, the dosage of ferrate(VI) was higher, the degradation of tetracycline and the self-degradation of ferrate(VI) also higher, finally the efficiency of ferrate(VI) was lower. The results said that the various mechanisms effects the reaction of ferrate(VI) oxidation, it required the consideration of the characteristics of the target compound for optimal degradation efficiency. Additionally, intermediate products were detected with LC/MS/MS and three degradation pathways were proposed.

• 한국식품영양학회지
• /
• 제9권3호
• /
• pp.307-313
• /
• 1996

The study was performed under the various conditions, such as the edible parts and particle sizes of Allium, the concentrations, the temperatures, and the pH of heavy metal solutions to investigate their adsorption capacity of heavy metals by genus Allium. The adsorption amount of Cd by Allium in the aqueous solution was apparently higher than that of Zn by them. The larger the particle size of welsh onion and shallot was, the higher the adsorption of Cd was. But the adsorption ratio was not different. As the temperature increased, the amount of heavy metal adsorption increased in general, but the adsorption of Cd by wild garlic, Zn by garlic decreased. Adsorption of Cd and Zn to Allium was not affected by the various pH. The correlation between the amount of components in edible putts of Allium and that of adsorption of heavy metals was significantly high in amino acids containing sulfhydryl radical (-SH) and vitamin B2.

• Bulletin of the Korean Chemical Society
• /
• 제28권9호
• /
• pp.1477-1484
• /
• 2007

Artificial neural networks (ANNs), for a first time, were successfully developed for the prediction partial molar heat capacity of aqueous solutions at infinite dilution for various polar aromatic compounds over wide range of temperatures (303.55-623.20 K) and pressures (0.1-30.2 MPa). Two three-layered feed forward ANNs with back-propagation of error were generated using three (the heat capacity in T = 303.55 K and P = 0.1 MPa, temperature and pressure) and six parameters (four theoretical descriptors, temperature and pressure) as inputs and its output is partial molar heat capacity at infinite dilution. It was found that properly selected and trained neural networks could fairly represent dependence of the heat capacity on the molecular descriptors, temperature and pressure. Mean percentage deviations (MPD) for prediction set by the models are 4.755 and 4.642, respectively.

• Environmental Engineering Research
• /
• 제7권3호
• /
• pp.149-157
• /
• 2002

• 대한한방내과학회지
• /
• 제43권4호
• /
• pp.503-513
• /
• 2022

Objectives: The antitussive, expectorant, and anti-inflammatory effects of Mahwangyounpae-tang (MHYPT) aqueous extracts were observed in appropriate animal models of various respiratory disorders. Methods: MHYPT aqueous extracts were orally administered once a day for 11 days at dose levels of 400, 200, and 100 mg/kg. The effect of MHYPT was determined by comparing its antitussive effect with theobromine (TB), its expectorant effect with ambroxol (AM), and its anti-inflammatory effect with dexamethasone (DEXA). Results: MHYPT aqueous extracts (400 mg/kg) showed favorable antitussive effects comparable to those of TB (50 mg/kg) in the NH₄OH-exposure coughing mouse model and expectorant effects comparable to those of AM (250 mg/kg) in the phenol red-secretion mouse model, but MHYPT (400 mg/kg) showed less anti-inflammatory activity compared to DEXA (1 mg/kg) in the xylene-induced acute inflammatory mouse ear model under the experimental conditions used. Conclusion: MHYPT aqueous extracts administered at dosage levels of 400, 200, and 100 mg/kg induced dose-dependent and favorable antitussive, expectorant, and anti-inflammatory activities that occurred by simultaneous modulation of the activity of mast cells and respiratory mucous production under the experimental conditions used in this study.

• 동력기계공학회지
• /
• 제20권1호
• /
• pp.42-49
• /
• 2016

This study showed that on-site ferrate(VI) solution was synthesized by wet oxidation method and applied aqueous 2,4-dichlorophenol(DCP) solution to evaluate the degradation efficiency. On-site ferrate(VI) solution was synthesized by putting $FeCl_3{\cdot}6H_2O$ in the strong alkali solution with NaClO and NaOH and applied DCP solution directly. DCP solution was extracted by the liquid-liquid method and analyzed by GC-ECD. The factors such as pH, DCP initial concentration, injected ferrate(VI) dosage, temperature were investigated. The optimum pH and temperature conditions of DCP degradation were obtained in neutral condition and $35^{\circ}C$. And the experimental results showed that DCP removal efficiency also increased with the decrease of DCP initial condition and the injected ferrate(VI) dosage.

• 한국수소및신에너지학회논문집
• /
• 제27권3호
• /
• pp.290-297
• /
• 2016

The absorbent loss due to degradation in $CO_2$ capture process using aqueous alkanol amine solution has adverse effect on the economics of overall process. The degradation causes absorbent loss, equipment corrosion, foaming, adhesive material producing and viscosity increase in operation. In this study, the degradation characteristics of $CO_2$ capture process using MEA (monoehtanolamine) under various conditions such as $O_2$ partial pressure, $CO_2$ loading and absorbent temperature. The effects of iron, which generated from the equipment corrosion, on absorbent degradation were studied using $Fe_2SO_4$ containing MEA solution. The produced gases were analyzed by FT-IR(Fourier Transform Infrared Spectrophotometer) and the specifically measured $NH_3$ concentration was used as a degradation degree of aqueous MEA solution. The experiments showed that the higher $CO_2$ loadings (${\alpha}$), $O_2$ fraction ($y_{O2}$) and reaction temperature enhanced the more degradation of aqueous MEA solution. Comparing other operation parameters, the reaction temperature most affected on the degradation. Therefore, it could be concluded that the above parameters affects on degradation should be considered for the selections of $CO_2$ absorbent and operating conditions.

• Archives of Pharmacal Research
• /
• 제25권3호
• /
• pp.381-386
• /
• 2002

The objective of this study was to link conformational changes of proteins at a water/methylene chloride interface to their destabilization upon emulsification. When 4 aqueous protein solutions (bovine serum albumin, $\beta$-lactoglobulin, ovalbumin, or ribonuclease) were emulsified in methylene chloride, considerable proportions of all the proteins became water insoluble aggregates. There were also noticeable changes in the compositions of their water-soluble species. A series of water/methylene chloride interfacial reactions upon the proteins was considered a major cause of the phenomena observed. Based on this supposition, the interfacial tension was determined by a Kruss DVT-10 drop volume tensiometer under various experimental conditions. It substantiated that the interfacial tension was high enough to cause the adsorption of all the proteins. Under our experimental conditions, their presence in the aqueous phase resulted in reductions of the interfacial tension by the degrees of 8.5 - 17.1 mN $m^{-1}$. In addition, dynamic changes in the interfacial tension were monitored to compare relative rates at which the adsorbed proteins underwent conformational, structural rearrangements at the interface. Such information helped make a prediction about how easily proteins would denature and aggregate during emulsification. Our study indicated that emulsifying aqueous protein solutions in organic solvents should be handled with care, due to adverse interfacial effects.

• 복식문화연구
• /
• 제12권3호
• /
• pp.407-414
• /
• 2004

A natural dye aqueous walnut shell extract was obtained by extraction of walnut shell using water at various conditions in this study. Silk fabrics were dyed at various dyeing and mordanting conditions using walnut shell extract and various mordants (Al, Cu, Fe ions). Studies have been made on the effects of dyeing and mordanting conditions on the dyeing properties and fastness (light, water and dry cleaning fastness) of dyed silk Fabric. The results obtained in this study were as follows;. The dye content in the walnut shell extract increased with increasing extraction temperature to 90℃ and extraction time to 120min, and thereafter the dye content decreased a little. The dry cleaning and water fastness of non-mordanted silk fabrics were better than those of mordanted silk fabrics.