• Journal of the Korean Society of Safety
• /
• v.28 no.6
• /
• pp.23-28
• /
• 2013

In order to improve extinguishing performance of water mist, many studies of additives have been conducted. In this study, viscosity agent which has the ability to improve extinguishing performance by adhering to the surface on fire was used and fluorine-free surfactant was also added to water to enhance water's wetting ability. This study aimed to verify optimal concentration of extinguishing of additives according to fire source and extinguishing performance by comparison with pure water. In case of wood crib fire, the results show that flame suppression and extinguishing time of sodium alginate 0.4 wt.% are 3.4 times and 2.2 times shorter than those of pure water in 0.2 MPa respectively. It seems that large amount of water adhere to surface on fire, thus cooling effect on surface was enhanced. Also water consumption of sodium alginate 0.4wt.% is up to 65% lower than that of pure water. In case of heptane fire, extinguishing time of cocobetaine 0.1 wt.% is 9.7 times shorter than that of pure water in 0.2 MPa. It is thought that because cocobetaine can block oxygen and suppress oil mist by making emulsion film on fire surface due to a low surface tension. On the other hand, water consumption of cocobetaine 0.1 wt.% is 92% lower than that of pure water.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.666-670
• /
• 2001

Levofloxacin is L-form stereoisomer of ofloxacin. It has better antibacterial activity than D-oflxacin. In this study, levofloxacin was produced enantioselectively by using high density culture of recombinant E. coli containing a foreign esterase gene. Final cell concentration was 89 g/L at the end of fed-batch culture and the cells were used for levofloxacin production after IPTG induction at the optimized condition. For the immobilization of recombinant E. coli. 1.5% sodium alginate showed the best result to maintain enzyme activity and enantioselectivity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.1 s.113
• /
• pp.45-53
• /
• 2006

This study was carried out to produce high functional and biodegradable coating agents for pulp mold by evaluating various kinds of biodegradable polymers. Five kinds of biodegradable polymers were used. In addition, the mixture of the carboxymethylated starch and biodegradable polymers(${\kappa}$-carrageenan, chitosan) were used for mixed coating agents. Physical properties of coated paperboards were evaluated. Conclusions obtained were as follows. 4% ${\kappa}$-carrageenan and 5% chitosan showed higher water and oil resistance. 10% sodium alginate, 4% corn zein and 15% polycaprolactone showed high water resistance while no improvement was found on oil resistance. The optimum mixture ratios for the mixed coating agents were 90:10(carboxymethylated starch : ${\kappa}$-carrageenan) and 50:50(carboxymethylated starch : chitosan). Since these mixed coating agents have excellent biodegradability with higher water and oil resistance, these can be used for the environmental-friendly coating agents.

• Membrane and Water Treatment
• /
• v.8 no.5
• /
• pp.483-498
• /
• 2017

Novel mixed matrix membranes of Sodium Alginate (NaAlg) were developed by the incorporation ofunmodified, modified Phosphomolybdic acid (PMA) then cross-linked with glutaraldehyde externally. These membranes were prepared by the solution casting technique. Pervaporation (PV) experiments have been performed with pure NaAlg, unmodified NaAlg-PMA5, NaAlg-PMA10, modified NaAlg-mPMA5, and NaAlg-mPMA10 (wt. % of PMA 5 and 10) at 30, 40 and $50^{\circ}C$, to separate water-isopropanol feed mixtures containing 10-30 wt. % of water. Pervaporation results of NaAlg-mPMA10 produced a highest separation factor of 9028 with a flux of $0.269kg/m^2.h$ for 10 wt. % of water containing feed mixture. Both separation factor and flux for water increased significantly with increasing content of mPMA into NaAlg; a significant improvement in PV performance was observed for NaAlg-mPMA5 and NaAlg-mPMA10 membranes when compared to pure NaAlg& PMA-5, PMA-10 membrane.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.9
• /
• pp.1470-1476
• /
• 2020

Objective: This study was carried out to investigate physicochemical properties, and antioxidant and antimicrobial activities of low-fat sausages (LFSs) covered with sodium alginate (SA) film alone and with powder film (TSA-film) formed by cross-linking cherry tomato powder (CTP) and SA with calcium chloride (CaCl₂). Methods: Sausages covered with the biodegradable film were assessed based on the measurement of pH, color (L^⋆, a^⋆, b^⋆), proximate analysis, expressive moisture (EM), texture profile analysis, total plate counts (TPC), violet red bile, and 2-Thiobarbituric acid reactive substances (TBARS) during storage under refrigeration. LFSs wrapped with TSA-film were compared with those wrapped with SA-film and without film (control) during storage at 10℃ for 35 days. Results: The LFSs covered with the mixed film had lower pH, lightness (L^⋆), EM%, TBARS, and TPC, but lower yellowness (b^⋆) and hardness values than those wrapped with TSA-film alone. Conclusion: Lipid oxidation and microbial growth was retarded in sausages covered with biodegradable films, especially multiple films as compared to single film, thereby resulting in extended shelf-life of the LFSs.

• Journal of Life Science
• /
• v.14 no.1
• /
• pp.167-173
• /
• 2004

The optimal conditions for the continuous production of $\gamma$-aminobutyric acid by immobilization of Lactobacillus brevis BH-21 using column type reactor were investigated. The optimal conditions of operation were 2.2 mm diameter bead of 3.0% sodium alginate at 10 mL/h of substrate feeding rate. Continuous production by immobililzed cells showed the highest productivity with replacement of fresh medium in every 48h for fourth fermentatoin cycle following the rendition of $\gamma$-aminobutyric acid productivity. A productivity of $\gamma$-aminobutyric acid could be obtained for 25 days by continuous column type reactor under optimal conditions.

• Environmental Engineering Research
• /
• v.24 no.3
• /
• pp.376-381
• /
• 2019

In this study, a poly(vinyl) alcohol/sodium alginate (PVA/SA) mixture was used to fabricate core-shell structured gel beads for autotrophic single-stage nitrogen removal (ASNR) using aerobic and anaerobic ammonia-oxidizing bacteria (AAOB and AnAOB, respectively). For stable ASNR process, the mechanical strength and oxygen penetration depth of the shell layer entrapping the AAOB are critical properties. The shell layer was constructed by an interfacial gelling reaction yielding thickness in the range of 2.01-3.63 mm, and a high PVA concentration of 12.5% resulted in the best mechanical strength of the shell layer. It was found that oxygen penetrated the shell layer at different depths depending on the PVA concentration, oxygen concentration in the bulk phase, and free ammonia concentration. The oxygen penetration depth was around $1,000{\mu}m$ when 8.0 mg/L dissolved oxygen was supplied from the bulk phase. This study reveals that the shell layer effectively protects the AnAOB from oxygen inhibition under the aerobic conditions because of the respiratory activity of the AAOB.

• Korean Chemical Engineering Research
• /
• v.61 no.4
• /
• pp.584-590
• /
• 2023

In this study, we focus on the recycling of cardboard waste and sugarcane bagasse (SCB) for the preparation of carboxymethyl cellulose (CMC) and its conversion into a biodegradable film. Sodium alginate (SA) was added to form a biodegradable composite film. SA was used to increase film permeability. Glycerol, which is a plasticizer, was used to increase the tensile strength (TS) and film expansion. To characterize the CMC, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used. The addition of olive oil to the CMC-SA matrix highlighted its antimicrobial property against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). A slight decrease in tensile strength was observed with the addition of olive oil (OO), which improved the functional properties of the control films as well as lowered moisture content and water solubility. But considering all other factors, the composite films obtained from sugarcane bagasse and cardboard waste incorporated with olive oil are suitable for applications in the field of food packaging.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.37 no.1
• /
• pp.1-6
• /
• 2004

In preparing sodium alginates from sea tangle (Laminaria japonica) powder using the Mexican process, alkaline extraction, conversion to alginic acid and reversion to sodium alginates were used to increase purity. The effect of hot water treatment and dialysis on measuring the average molecular weight of sodium alginates were investigated. Intrinsic viscosity and average molecular weight of sodium alginates after dialysis were higher than those before dialysis. Average molecular weight of sodium alginates treated with hot water was higher than that without. Hot treatment has little effect on the ash content of sodium alginates. Ash content of sodium alginates before dialysis were $27-30\%$ those after dialysis were $10\%.$ After dialysis, Na content was highest $(89-91\%),$ K was $11-12\%,$ Ca was $1.9\%,$ and Mg was $0.05\%.$ Ash content of alginates had little effect on average molecular weight. SAV (slope of apparent viscosity) of alginates solution after dialysis showed higher values than before. SAV of the alginates with hot water treatment were higher than without treatment.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.4
• /
• pp.795-801
• /
• 2016

This study is on the denitrification process using the sodium alginate and $CaCl_2$ as a flocculant. Removal techniques of nitrate nitrogen from waste water are reverse osmosis, ion exchange, electro dialysis and biological method etc. We tried to remove nitrate nitrogen with flocculation and sedimentation method in the present study. Calcium alginate is expected to form a chelate bond with nitrate nitrogen in the solution. So the effects of flocculantt component, flocculation reaction time, molar ratio of the flocculant, flocculant injection rate are studied to determine the best removal rate of nitrate nitrogen. In addition, we tried to determine the nitrate nitrogen removal mechanism by analyzing the structure and component ratio of the configuration after the agglutination precipitate by FE-SEM and EDS. As a result, the nitrate nitrogen removal mechanism is turned out to form calcium-nitro-alginate, and the best mole ratio of flocculating agent is 1 : 1, the injection rate of the flocculant was up to 2%, the removal rate of the nitrate nitrogen to be 56.7% in the synthetic wastewater.