• Membrane and Water Treatment
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• v.8 no.4
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• pp.337-353
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• 2017

Membrane fouling at different solids retention times (SRT) (7, 12 and 20 days) was studied under well-controlled conditions in a laboratory-scale aerobic submerged membrane bioreactor under constant biomass concentration using a synthetic high strength wastewater. An increase in SRT was found to improve membrane performance and this correlated to changes in the total production of bound extracellular polymeric substances (EPS), and the composition and properties of bound EPS using X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectroscopy (FTIR) and floc sizes. A larger amount of total bound EPS was found at the lowest SRT (7 days) tested but the ratio of proteins (PN) to carbohydrates (CH) in bound EPS increased with an increase in SRT. Similarly, the quantity of soluble microbial products (SMP) decreased with an increase in SRT and the SMP PN/CH ratio increased with an increase in SRT. SMP concentrations positively correlated to the percentage of membrane pore blocking resistance. The quantity of total bound EPS and total SMP positively corresponded to the membrane fouling rate, while the PN/CH ratio in the bound EPS and SMP negatively correlated to the membrane fouling rate. The results show that both the quantity and composition of bound EPS and SMP and floc sizes are important in controlling membrane fouling.

• Membrane Journal
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• v.27 no.1
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• pp.60-67
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• 2017

Recently, the economic, social and environmental significance of the water industry is increasing significantly due to rapid global urbanization, population growth, and imbalance in demand and supply of water resulted by climate change. The type of these water industries are all different and they can be distinguished by the kinds of membranes used. Mainly, polymer materials that have excellent physical and chemical stability are used, but recently various methods of assigning hydrophilicity have been introduced due to their hydrophobic properties. In this study, hydrophilic polymers of four types were introduced into a commercially available hollow support to assign hydrophilicity. Furthermore, the morphology of the coated hollow support through FE-SEM was confirmed as well. Also the contact angle was measured to examine the degree of hydrophilicity of the coated hollow support with each polymer. Finally,.effect of different time on water permeability as well as the relationship between water permeability and hydrophilic polymers were investigated. As a result, the coating with 1 wt% of pluronic has good hydrophilicity degree, and shows the excellent water permeability without blocking the pore of the hollow fiber. Therefore, it can be concluded that the hydrophilic coating using pluronic polymer is most suitable as the water treatment.

• Environmental Engineering Research
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• v.11 no.2
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• pp.91-98
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• 2006

There is a possibility of the production of the air bubbles in membrane pores due to the reduction in pressure during membrane filtration. The effect of fine air bubbles from dissolved gases on microfiltration was investigated in the submerged membrane bio-reactor (SMBR). The $R_{air}$ (air bubble resistance) was defined as the filtration resistance due to the air bubbles formed from the gasification of dissolved gases. From the results of filtration tests using pure water with changes in the dissolved oxygen concentration, the air bubbles from dissolved gases were confirmed to act as a foulant and; thus, increase the filtration resistance. The standard pore blocking and cake filtration models, SPBM and CFM, respectively, were applied to investigate the mechanism of air bubble fouling on a hollow fiber membrane. However, the application of the SPBM and CFM were limited in explaining the mechanism due to the properties of air bubble. With a simple comparison of the different filtration resistances, the $R_{air}$ portion was below 1% of the total filtration resistance during sludge filtration. Therefore, the air bubbles from dissolved gases would only be a minor foulant in the SMBR. However, under the conditions of a high gasification rate from dissolved gases, the effect of air bubble fouling should be considered in microfiltration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.11-15
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• 1977

Brownish discoloration develops very rapidly in the storage of dried oyster. This undesirable browning is mainly caused by the series of reactions of sugar-amino condensation, enzymatic oxidation of tyrosine and/or the oxidative rancidity of lipids in the tissue of oyster. Sulfites are commonly used as inhibitors for Maillard type browning reactions in agricultural products. The inhibitory effect of sulfite treatment on canned oysters was also confirmed in some investigations. The results suggested that sulfites not only work on blocking tile amadori rearrangement but also on the reduction of free tyrosine which retards the progress of enzymatic oxidation of tyrosine tyrosinase. In this paper, the effect of sodium sulfite treatment on the reduction of reducing sugar and free tyrosine as a function i)f browning inhibition in oyster was tested and other treatment with glucose-oxidase and yeast were also applied. In preparation of samples, fresh oysters were soaked in sodium sulfite solution by various concentration for different treating times, washed in running water to remove the sulfite residue, and finally dried in the shade. In the result, the treatment of sodium sulfite was certainly effective on the reduction of both free tyrosine and reducing sugars in fresh oyster. The best results were obtained by the treatment of 0.5M sodium sulfite solution for 60 minutes each for soaking and washing. Treatment with, glucose-oxidase and yeast solutions, however, did appear somewhat effective but it required so much time for a certain effect that it seemed not practically applicable.

• The Research Journal of the Costume Culture
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• v.18 no.2
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• pp.371-381
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• 2010

The pine needles can be used for four seasons in normal living and it can be taken friendly everywhere as it is distributed over 50% in Korea. The pine needles consist of vitamins, protein, minerals, essential oil and enzyme related to antimicrobial activity. It has effect like high blood pressure, neuralgia and hanged over by terpene, glucokinin, rutin, apigenic acid and tannin. Also the extract of them can be used for dyeing of fabrics. However, the extract components and effects of them are not well known yet. Therefore, the purpose of this study was to investigate the volatile components of the pine needles extract and functionality. The pine needles extract was dyed into various fabrics(nylon, silk, wool and soybean) and mordanted with Al, Cu, Cr, Fe and Sn. The extracted aroma compounds were compared by gas chromatography-mass spectrometry. The major volatile compounds of pine needles verified by using SPME were alpha-pinene, beta-pinene, beta-phellandrene, caryophyllene, ethanon, benzen. A total of 15 compounds were identified by using the SPME fibers. In the UV-visible spectra, the maximum absorption of wavelength of the pine needles ethanol extract appeared at 460, 630nm for chlorophyll component and at 237, 281nm for tannin component with the pine needles distilled water extract. Most of sample showed high antibacterial effect in none mordant but wool fabric showed high antibacterial effect in mordants. The result of UV block test showed a superior ability of blocking ultraviolet ray infiltration in all sample.

• Journal of Conservation Science
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• v.26 no.4
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• pp.385-395
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• 2010

This study aimed to identify weathering factors and to assess the conservation environment through microclimatic analysis of Hyeonpung Seokbinggo (ice-storing stone warehouse). The stone blocks inside Seokbinggo suffered crack, displacement, break-out, exfoliation, efflorescence, brown and black discoloration, and biological colonization. Biological colonization represented the maximum deterioration rate(24%) among those weathering forms. The indoor microclimate showed parallel patterns with outdoor one, but the indoor temperature and relative humidity ranged far narrower than outdoor and remained steady. The environmental characteristics resulted from blocking-out of outdoor heat by the closed entrance and surrounding microtopography. This prevented water condensation and freezing effects, so that it reduced physical deterioration of rock, and maximized ice-storing effect for long time. However, contrary to positive effect, extremely high relative humidity over 99% accelerated biological colonization inside the Seokbinggo.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.425-436
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• 2021

In this study, chemically enhanced steam cleaning(CESC) was applied as a novel and efficient method for the control of organic and inorganic fouling in ceramic membrane filtration. The constant filtration regression model and the resistance in series model(RISM) were used to investigate the membrane fouling mechanisms. For total filtration, the coefficient of determination(R²) with an approximate value of 1 was obtained in the intermediate blocking model which is considered as the dominant contamination mechanism. In addition, most of the coefficient values showed similar values and this means that the complex fouling was formed during the filtration period. In the RISM, R _c/R _f increased about 4.37 times in chemically enhanced steam cleaning compared to physical backwashing, which implies that the internal fouling resistance was converted to cake layer resistance, so that the membrane fouling hardly to be removed by physical backwashing could be efficiently removed by chemically enhanced steam cleaning. The results of flux recovery rate showed that high-temperature steam may loosen the structure of the membrane cake layer due to the increase in diffusivity and solubility of chemicals and finally enhance the cleaning effect. As a consequence, it is expected that chemically enhanced steam cleaning can drastically improve the efficiency of membrane filtration process when the characteristics of the foulant are identified.

• The Journal of Internal Korean Medicine
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• v.41 no.1
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• pp.44-58
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• 2020

Objectives: This study was conducted to identify the protective effects of Chongmyunggongjin-dan (CMGJD) on Hydrogen peroxide (H₂O₂)-induced apoptosis mechanisms in C6 glial cells. Method: We used CMGJD after distilled water extraction, filtration, and lyophilization. The ROS scavenging effect was examined by fluorescence microscopy. Expression levels of proteins related to ROS generation were investigated by western blotting. Functional changes in organelles related to Reactive oxygen species (ROS) generation were investigated by immunoblotting and by verifying expression level of relevant enzymes. Results: The CMGJD extract protected the cells against H₂O₂-induced morphological changes and DNA fragmentation, inhibited the increase of Heme_oxygenase-1(HO^-1) and the decrease in catalase, protected against the loss of mitochondrial membrane potential, inhibited disturbances of lysosomal function, and induced an increase in peroxisomes. Conclusion: CMGJD was confirmed to have a protective effect on H₂O₂-induced C6 glial cell death possibly by blocking the pathways causing damage to subcellular organelles, such as mitochondria, lysosomes, and peroxisomes. We assume that CMGJD will be effective for the prevention and treatment of ischemic stroke in a clinical environment.

• Korean Journal of Oriental Medicine
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• v.2 no.1
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• pp.236-254
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• 1996

This study was carried out to investigate the tracheal muscle relaxation of water extracts of three kinds of Coptis rhizoma and also compare their effects with berberine and palmatine, which are the important alkaloid components of Coptis rhizoma, in isolated rat tracheal smooth muscle. As a result Coptis chinenis showed significant tracheal muscle relaxation on KCI-induced contraction and more markedly on carbachol-induced contraction in dose-dependent manner. Coptis japoinin exhibited also tracheal muscle relaxation on both contraction with slightly weaker activities than those of Coptis chinensts. The activities of the root hair of Coptis chinensis were the most weakest in three rhizomas. Berberine and palmatine had strong tracheal muscle relaxation, especially, on carbachol-induced contraction, however, their activities on KCI-induced contraction were weaker than that of Coptis chinenis. The inhibitory effects of three kinds of Coptis rhizoma on the contraction by KCI and carbachol were investigated to explain the process of their tracheal muscle relaxation. All rhizomas inhibited the contraction by both agents, among them, Coptis japonica showed the most significant effect, so indicating that the tracheal muscle relaxation of Coptis rhizoma may be concerned with the blocking of muscarine receptor and $Ca^{2+}$channel.

• Journal of Ocean Engineering and Technology
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• v.21 no.1 s.74
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• pp.7-17
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• 2007

Based on the Boussinesq wave model, the wave distribution in the Chagui-Do sea area in Jeju was simulated by applying the directional irregular waves at an incident boundary. The time and spatial variations of monthly mean wave height and period were investigated, which aims to provide basic information on optimal sites for wave power generation. The grid size and time interval of the Boussinesq wave model were validated by examining wave distributions around a surface piercing wall, fixed at sea bottom with a constant slope. Except for the summer season, the significant wave height is dominated by wind waves and appears to be relatively high at the north sea of Chagui-Do, which is open to the ocean, while it is remarkably reduced at the rear sea of Chagui-Do because of its blocking effect on incident waves. In the summer, the significant wave height is higher at the south sea, and it is dominated by the swell waves, which is contributed by the strong south-west wind. The magnitude of significant wave height is the largest in the winter and the lowest in the spring. Annual average of the significant wave height is distinctively high at the west sea close to the Chagui-Do coast, due to a steep variation of water depth and corresponding wave focusing effect. The seasonal and spatial distribution of the wave period around Chagui-Do sea reveals very similar characteristics to the significant wave height. It is suggested that the west sea close to the Chagui-Do coast is the mast promising site for wave power generation.