• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.2
• /
• pp.15-24
• /
• 1999

A new technique for recycling of white water was developed in order to reduce the calcium hardness in a closed OCC recycling system. Calcium ions present in the white water were precipitated as calcium carbonate by reacting with sodium carbonate, and the precipitated $CaCO_3$ was removed from the system using a flotation fractionation method, which has been commonly used in deinking process. In the flotation stage, a mixed gas of $CO_2$-air was purged into the flotation cell because the pH of $Na_2CO_3$-treated white water was reduced to neutral by $CO_2$ gas. Since $CaCO_3$ precipitate tends to stick onto fine fiber surface and then selectively removed from the white water, a proper amount of suspended solid in white water acts as an important factor for deciding the removal efficiency. By the application of $Na_2CO_3$ addition-$CO_2$ flotation to the short circulated white water, the calcium hardness was significantly reduced by 87% and more. Removal of calcium ions with fine fibers led to a drainage improvement, reduction of fresh water consumption, and enhanced efficiency of wet-end chemicals.

• Journal of the Korean Society of Industry Convergence
• /
• v.16 no.2
• /
• pp.41-46
• /
• 2013

On the purpose of helping the inhabitants living in farming, fishing villages, and islands for more safe and hygienic water from simple waterworks, experimental investigations were performed concerning the development of a water purifier with silver nanomaterial packed, having a function of the auto-disinfection. The results show as follows through such filteration and auto-disinfection processes. It is possible to get hygienic and safe water, for example, more than 95% of general bacteria, total coliforms, and fecal coliforms were removed. It is also possible to get good-quality water, for 49.4% of spent potassium permanganate and 85% and 63% of turbidity and conductivity were removed respectively. It is a very effective equipment, for 100% cost reduction of used chemicals was achieved by no-chemical disinfection process and THM was not generated.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.11b
• /
• pp.164-171
• /
• 1999

A new technique for recycling process water was developed in order to reduce the calcium hardness of the closed OCC recycling system. Calcium ions present in the white water were precipitated as calcium carbonate by a reaction with sodium carbonate and the CaCO$_3$precipitates were easily removed from the system by a dissolved air flotation(DAF) method. After the DAF stage, CO$_2$-gas was purged into the water because the pH of Na$_2$CO$_3$-treated white water was reduced to neutral by CO$_2$gas. Since CaCO$_3$precipitate tends to stick onto the fine fiber surface and then is selectively removed from the water, a proper amount of suspended solid in the process water acts as an important factor in deciding the removal efficiency. By the application of Na$_2$CO$_3$addition - DAF - CO$_2$purging to the short circulated white water the calcium hardness was significantly reduced by 92% and more. The removal of calcium ions with fine fibers led to drainage improvement, reduction of fresh water consumption, and enhanced efficiency of wet-end chemicals.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.2
• /
• pp.173-181
• /
• 2019

This study was carried out numerically to investigate the flow characteristics in the Venturi tube with $90^{\circ}$ T-branch tube and the inflow of condensed water into the Venturi tube from the branch tube. In this study, the diameter of the branch tube(1, 2, 3mm) and the neck diameter of the Venturi tube(0.3, 0.9, 1.5mm) were varied. The flow rate of the water at the Venturi tube inlet is 80cc/min and the water temperature is 288K. The condensed water temperature at the branch tube inlet is 355K. It was found that the velocity and pressure of the fluid near the branch point in the Venturi tube were more dependent on the diameter of the Venturi tube than the diameter of the branch tube. The temperature of the mixed water at the exit of the Venturi tube was the highest when the Venturi tube's neck diameter is 0.9mm and the branch tube diameter is 2mm. This means that the condensed water is flowing well through the branch tube.

• Fisheries and Aquatic Sciences
• /
• v.1 no.1
• /
• pp.129-146
• /
• 1998

Fatty acid compositions of seventy-two species of Korean fish muscle, 59 species of sea water fish and 13 species of fresh water fish, were studied. Polyunsaturated fatty acid (PUFA) was the richest fatty acid group in all fish samples, accounting for $38.0\pm10.3\%$ of total fatty acids. Monounsaturated fatty acids $(MUFA,\;31.4\pm9.67\%)$ and saturated fatty acids $(SFA, 30.5\pm3.81\%)$ showed a similar level. There was a positive correlation between the total lipid content and MUFA (r=0.7788, p<0.001) and a negative correlation between the total lipid content and PUFA (r= -0.7786, p<0.001) while there was no correlation between the total lipid content and SFA. The proportion of n-3 PUFA and n-6 PUFA was $29.7\pm8.73\%$ and $6,48\pm3.70\%$, respectively, in all fish samples. The n-3 PUFA was rich in sea water fish while n-6 PUFA was rich in fresh water fish. The migratory fish contained the highest level of the n-3 PUFA $(1.82\pm1.01g/100g\;muscle)$, followed by the fresh water fish $(1.09\pm1.04g/100g\;muscle)$, the reef fish $(0.90\pm0.60g/100g\;muscle)$ and the demersal fish $(0.77\pm0.38g/100g\;muscle)$. There was a positive correlation between the total lipid and n-3 PUFA content, $y=0.2083\times+0.05 (r=0.9352,\;p<0.0010)$.

• Macromolecular Research
• /
• v.17 no.7
• /
• pp.528-532
• /
• 2009

The size and shape of free volume (FV) holes available in membrane materials control the rate of gas diffusion and its permeability. Based on this principle, a segmented, thermo-sensitive polyurethane (TSPU) membrane with functional gate, i.e., the ability to sense and respond to external thermo-stimuli, was synthesized. This smart membrane exhibited close-open characteristics to the size of the FV hole and water vapor permeation and thus can be used as smart food packaging materials. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), positron annihilation lifetimes (PAL) and water vapor permeability (WVP) were used to evaluate how the morphological structure of TSPU and the temperature influence the FV holes size. In DSC and DMA studies, TSPU with a crystalline transition reversible phase showed an obvious phase-separated structure and a phase transition temperature at $53^{\circ}C$ (defined as the switch temperature and used as a functional gate). Moreover, the switch temperature ($T_s$) and the thermal-sensitivity of TSPU remained available after two or three thermal cyclic processes. The PAL study indicated that the FV hole size of TSPU is closely related to the $T_s$. When the temperature varied cyclically from $T_s-10{\circ}C$ to $T_s+10^{\circ}C$, the average radius (R) of the FV holes of the TSPU membrane also shifted cyclically from 0.23 to 0.467 nm, exhibiting an "open-close" feature. As a result, the WVP of the TSPU membrane also shifted cyclically from 4.30 to $8.58\;kg/m^2{\cdot}d$, which produced an "increase-decrease" response to the thermo-stimuli. This phase transition accompanying significant changes in the FV hole size and WVP can be used to develop "smart materials" with functional gates and controllable water vapor permeation, which support the possible applications of TSPU for food packaging.

• Current Research on Agriculture and Life Sciences
• /
• v.33 no.2
• /
• pp.57-63
• /
• 2015

In this study, the antioxidant activity of water and ethanol extracts from Hibiscus esculentus, Cirsium japonicum, Zizania latifolia and Kalopanax pictus for functional food source were examined. The optimal conditions for phenolic compounds extraction from medicinal plants were at 50% ethanol with Hibiscus esculentus and Cirsium japonicum var. ussuriense, at 40% ethanol with Kalopanax pictus and at 60% ethanol with Zizania latifolia. The total phenolic contents from the extracts of medical plants were determined to be 2.72~34.15 mg/g in the water extracts and 2.83~34.23 mg/g in the ethanol extracts. The electron-donating abilities (EDA) of the water and ethanol extracts were both above 74% at the low concentration of $50{\mu}g/mL$. The ABTS radical-cation decolorization was above 88% at $100{\mu}g/mL$ concentration in all the extracts of various medicinal plants. The antioxidant protection factor (PF) in the water and ethanol extracts of the Cirsium japonicum var. ussuriense extracts was $1.73{\pm}0.02PF$ and $1.76{\pm}0.01PF$ at $50{\mu}g/mL$ concentration respectively, and was higher than those of the other medicinal-plant extracts. The TBARs inhibition rates of all the medicinal-plant extracts, were above 80% at the $50{\mu}g/mL$ concentration except Hibiscus esculentus. These results confirmed that the various oriental medicinal plants (Hibiscus esculentus, Cirsium japonicum var. ussuriense, Kalopanax pictus and Zizania latifolia) that were included in this study are useful anti-oxidant and functional-food resources.

• Journal of Radiation Industry
• /
• v.6 no.2
• /
• pp.153-158
• /
• 2012

In this research, poly(acrylic acid) (PAAc) hydrogels containing zinc oxide particle were prepared by gamma-ray irradiation. PAAc powder was completely dissolved in distilled water at room temperature. Water-insoluble zinc oxide powder were added into the PAAc solution and stirred until totally dissolved. Finally, the mixture was irradiated by gamma-ray irradiation to make crosslinking. The effects of various parameters such as zinc ions' concentration, irradiation doses were varied and investigated in detail. PAAc hydrogels containing zinc oxide particle were characterized by gel content and swelling ratio. Moreover, the antibacterial properties of this material were evaluated by paper diffusion test against the Gram positive and Gram negative bacteria.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.5
• /
• pp.825-833
• /
• 2020

Currently, the K-Water uses various valves that can be remotely controlled for optimal water management. Valve system fault can be classified into rotor defects, stator defects, bearing defects, and gear defects of induction motors. If the valve cannot be operated due to a gear fault, the water management operation can be greatly affected. For effective water management, there is an urgent need for preemptive repairs to determine whether gear is damaged through failure prediction diagnosis.. Recently, deep learning algorithms are being applied for valve failure diagnosis. However, the method currently applied has a disadvantage of attaching a vibration sensor to the valve. In this paper, propose a new algorithm to determine whether a fault exists using a convolutional neural network (CNN) based on the voltage and current information of the valve without additional sensor mounting. In particular, a normalized Lisasjous diagram was used to maximize the fault classification performance in the CNN-based diagnostic system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.360-360
• /
• 2008

Steelmaking industry is widely known to use a lot of water and same amount of wastewater is generated. Although toxicity of wastewater from Steelmaking industry is low, it contains an amount of various organic materials and Fe-Oxides. It is important to recycle the wastewater because of water shortages and water pollution. In general, large-scale equipment is necessary to process the wastewater. On the other hand, superconducting high gradient magnetic separation (HGMS) system can process the wastewater in the small space. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Cryo-cooled Nb-Ti superconducting magnet was used for magnetic separator. This system can operate continuously because contaminated filters can keep on returning after cleaning. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. Filter cleaning system was developed to decrease the quantity of clean water. This research was supported by a grant from Korea Electrotechnology Research Institute, Republic of Korea.