• Analytical Science and Technology
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• v.18 no.3
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• pp.216-223
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• 2005

In this study, several kinds of volatile amines in ambiant air were collected and their concentrations were expected from the calibration curves prepared by standard solutions of 7 amines by the official measuring method prescribed in Japanese Offensive Odor Law. The obtained calibration curves showed a good linearity and the detection limit of trimethyl amine was found to be about 0.033 ppb (0.040 ng) in case of 50 liters air. It means that trimethyl amine could be detected with the concentration of lower than its permitting level at the border line of companies. As typical examples of measuring amines in air, results of investigation of two sewage works and one rendering plant around the capital area indicated that 4 kinds of amines, i.e. methyl amine, dimethyl amine, trimethyl amine and isopropyl amine were detectable and concentrations of trimethyl amine at the primary sedimentation pond and sludge dewatering building of the sewage plant A showed 9.07 ppb and 7.79 ppb respectively, being over the concentration of odor strength 2.5, And the aeration tank, excrement input facility and indoor of maintenance room of excrement process building in the sewage plant B showed 70.0 ppb of dimethyl amine and 2.44 ppb of trimethyl amine.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1566-1573
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• 2014

Although most algae cultivation systems are operated in suspended culture, an attached growth system can offer several advantages over suspended systems. Algal cultivation becomes light-limited as the microalgal concentration increases in the suspended system; on the other hand, sunlight penetrates deeper and stronger in attached systems owing to the more transparent water. Such higher availability of sunlight makes it possible to operate a raceway pond deeper than usual, resulting in a higher areal productivity. The attached system achieved 2.8-times higher biomass productivity and total lipid productivity of $9.1g\;m^{-2}day^{-1}$ and $1.9g\;m^{-2}day^{-1}$, respectively, than the suspended system. Biomass productivity can be further increased by optimization of the culture conditions. Moreover, algal biomass harvesting and dewatering were made simpler and cheaper in attached systems, because mesh-type substrates with attached microalgae were easily removed from the culture and the remaining treated wastewater could be discharged directly. When the algal biomass was dewatered using natural sunlight, the palmitic acid (C16:0) content increased by 16% compared with the freeze-drying method. There was no great difference in other fatty acid composition. Therefore, the attached system for algal cultivation is a promising cultivation system for mass biodiesel production.

• Food Science and Preservation
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• v.14 no.6
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• pp.695-701
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• 2007

This study was carried out to develop a standard methods of mechanized salt-inserting salting process for winter cabbage to produce kimchi. Mid or large scaled mechanized kimchi plants were surveyed to select dominant variables of the mechanized salting process. Salt concentration of salting water, salting time and dewatering time were selected as the dominant variables of the salting process. A series of laboratorial experiment was performed with winter cabbage to determine desirable conditions for the variables. A supplementary experiment with cabbages of the other seasons was executed also to compare the determined conditions each other. Finally the determined conditions of the salting process were tested by plant scale experiments with winter cabbage and proved their validity.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.5
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• pp.211-217
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• 2020

Earthquake preparedness has become more important with recent increase in the number of earthquakes in Korea, but many existing structures are not prepared for earthquakes. There are various types of liquefaction prevention method that can be applied, such as compaction, replacement, dewatering, and inhibition of shear strain. However, most of the liquefaction prevention methods are applied before construction, and it is important to find optimal methods that can be applied to existing structures and that have few effects on the environment, such as noise, vibration, and changes in underground water level. The purpose of this study is to estimate the correlation between the displacement of a structure and variations of pore water pressure on the ground in accordance with the depth of the sheet file when liquidation occurs. To achieve this, a shaking table test was performed for Joo-Mun-Jin standard sand and an earth pressure, accelerometer, pore water pressure transducer, and LVDT were installed in both the non-liquefiable layer and the liquefiable layer to measure the subsidence and excess pore water pressure in accordance with the time of each embedded depth. Then the results were analyzed. A comparison of the pore water pressure in accordance with Hsp/Hsl was shown to prevent lateral water flow at 1, 0.85 and confirmed that the pore water pressure increased. In addition, the relationship between Hsp/Hsl and subsidence was expressed as a trend line to calculate the expected settlement rate formula for the embedded depth ratio.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.271-278
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• 2006

We used polymers of alternating cationic and anionic nature to build up shells on fiber surfaces, strengthen the worn-out fibers and improve paper properties made from such fibers. OCC and ONP pulps were either dipped or salted out in the cationic polyallylamine, polyacrylamide and starch solutions. After centrifugal drying, these were followed by treatments in anionic polyacrylic acid, poly-acrylamide, and starch solutions, respectively. The shell-enhanced fibers were formed into handsheets and their physical properties evaluated. The results show that building multiple shells on worn-out fiber surfaces can strengthen the fibers and paper. The simpler and more practical impregnation-centrifuging treatment provided the desired effects, whereas salting out the polymers produced somewhat superior fibers. The latter process, were impractical, however. The first pair of polymeric shells imparted marked strength improvement, whereas later layers had diminishing efficacies. Overall, the methods can improve fiber quality, attaining paper strength requirements without resorting to expensive measures. Alternate cationic polymer and filler powders were also deposited on fiber surface based on the micriparticle system in an anticipation of stiffness gains. Platy minerals, such as montmorillonite, bentonite, sericite, clay and talc were added following cationic PAM. After dewatering of polymer-pigment shelled fiber of one to 3 pairs of layers, handsheets either calendered or uncalendered were evaluated. The results indicate that regardless of calendaring, stiffness of the handsheets did not improve appreciably while certain other strength properties showed gains. We also attempted the novel starch gel filler addition method wherein tapioca starch and filers (PCC, sericite or clay) were mixed at high solids content of 50% and cooked until gelatinized. The filled handsheets were dried under various conditions and then tested for their properties. Improvements in strengths of modified filled paper were observed.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.25-31
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• 2023

Horizontal drainage, which are representative dewatering method of domestic and foreign slope, are applied to reducing pore water pressure. Accordingly, several previous studies have been conducted, but horizontal drainage are standardized which is an unclean standard for a quantity calculation in filed. Therefore, this study presents field soil and laboratory model box to identify a drainage performance and influencing factors of various horizontal drainage. Furthermore, this study verifies the performance comparison of drainage shape or size according to different particle size distributions. In the outflow results for steady state, the study found that all samples are drained at a constant rate after a minimum of 3 minutes to maximum of 15 minutes. In the case of comparing the outflow per hour (Unit flux) in coarse grained soils, it found that drainage shape and size affect drainage performance. In the result, the future expected to be used basic data that experiment of drainage performance on fine grained soils and determine the quantity.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.102-113
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• 2000

This study was conducted to investigate the expandibility of sludge treatment by earthworm through real scale experiment and the optimum counter-plan for organic sludge treatment. For the purposes, sludge removal efficienciesof night-soil using earthworm and it's behavior according to the transplanting methods of the earthworm on non-cover worm bed or in the green house worm bed were compared. Sludge uptake rates on non-cover worm bed for 6 months were $0.27{\sim}0.33ton/m^2$ and the excrement of earthworm yields $0.15ton/m^2$(44.1~46.7% of raw night soil sludge dosage). These results were not much different from the worm bed in the green house. The average and maximum earthworm density were about $6.5kg/m^2$ and $7kg/m^2$ respectively on the non-cover worm bed. The density of the worm bed was comparatively higher in spring and fall terms but lower in summer. The amount of old earthworm was much plenty than young earthworm on the non-cover worm bed, resulting in reverse distribution type of pyramid. From the experiments on non-cover worm bed(7,000 pyeong)and in the green house worm bed(1,200 pyeong), it was concluded that landfill and transporting cost could be reduced when the earthworm was applied for the night-soil sludge treatment. Profits from the excrement sale of earthworm was 9,600,000 won. Through this study, it was founded that earthworm treatment method for organic sludge are much more environmentally sound than landfill treatment.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.13-22
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• 2006

The geotextile have been used in filtration and drainage for over 30 years in many applications of civil and environmental projects. Geotextile tube is compound technology of filtration and drainage property of geotextile. Geotextile have been used for various types of containers, such as small hand-filled sandbags, 3-dimensional fabric forms for concrete paste, large soil and aggregate filled geotextile gabion, prefabricated hydraulically filled containers, and other innovative systems involving containment of soils using geotextile. They are hydraulically filled with dredged materials. It have been applied in coastal protection and scour protection, dewatering method of slurry, and isolation of contaminated material. Recently, geotextile tube technology is no longer alternative construction technique but suitable desired solution. This paper presents the behavior of geotextile tube composite structure by 2-D limit equilibrium and plane strain analysis. 2-D limit equilibrium analysis was performed to evaluate the stability of geotextile tube composite structure for the lateral load and also the plane strain analysis was conducted to determine the design and construction factors. Based on the results of this paper, the three types of geotextile tube composite structure is stable. And the optimum tensile strength of geotextile is 151kN/m and maximum pumping pressure is 22.7kN/m.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.722-729
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• 1997

The study was undertaken to extend the shelf life of filleted and salted fishes such as mackerel and jacopever. These filleted and salted fishes were dehydrated by dewatering sheet containing sodium polyacrylate resin at $5{\pm}1^{\circ}C$, wrapped with low density polyethylene film, and then stored at $-18{\pm}2^{\circ}C$. During the frozen storage, the change of brown pigment formation, peroxide value, carbonyl value, drip formation content in the cold-osmotic dehydrated fishes after salt dipping were much lower than those of non-dehydrated ones. Moreover, the proteins and Ca-ATPase in the cold-osmotic dehydrated fishes after salt dipping were more stable than those of non-dehydrated ones during frozen storage. It was supposed that the cold-osmotic dehydration pretreatment processing for filleted and salted fishes was useful in improvement of the frozen storage stability.

• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.11-18
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• 2006

Geotextile has been used for various types of containers, such as small hand-filled sandbags, 3-dimensional fabric forms for concrete paste, large soil and aggregate filled geotextile gabion, prefabricated hydraulically filled containers. They are hydraulically filled with dredged materials and have been applied in coastal protection and scour protection, dewatering method of slurry, temporary working platform for bridge construction, temporary embankment for spill way dam construction. Recently, geotextile tube technology is no longer alternative construction technique but suitable desired solution. The paper presents the stability behavior of geotextile tube composite structure by 2-D limit equilibrium and slope stability analysis. 2-D limit equilibrium analysis was performed to evaluate the stability of geotextile tube composite structure to the lateral earth pressure and also transient seepage and stability analysis were conducted to determine the pore pressure distribution by tide variation and slope stability. Based on the results of this paper, the three types of geotextile tube composite structure is stable and also slope stability of overall geotextile tube composite structures is stable with the variation of tidal conditions.