• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.706-712
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• 1999

PSD (particle size distribution) for 2,000 mg/$\ell$ natural loess in seawater showed normal distribution cure at 0 minute settling time, accompanying with very large particle distribution range with its mean particle diameter of 31.6 $\mu$m and coencient of variance of $72.6\%$, With elapsed time it showed that the PSD was rapidly changed from normal distribution cure to abnormal distribution curve, steepened the right-hand side of it and its coefficient of variance was getting increased because of rapid settling of large size particles, Cumulative weight distribution showed that 2,000 mg/$\ell$ natural loess in seawater was almost $100\%$ constituted of particles bigger than 20 $\mu$m in diameter. Ratio of $V_s/(D_{bm})^{1/2}$ for loess particles in seawater was increased with increase of particle size in geometrical progression. Almost all loess particles in seawater had Stokes settling velocity not less than 2,255 times of Brownian diffusion coefficient, There was almost to EDL (about 0.4 nm) around natural loess particles in seawater, Thus, there was always LVDW attractive force between loess particles approaching each other in seawater, and almost no EDL repulsive force. Loess particles were not always in the condition of easy floe formation. Concentration of natural loess in seawater increasing from 400 mg/$\ell$ to 10,000 mg/$\ell$, characteristics of the settling was changed from Type I settling (discrete settling) to Type II settling (flocculation settling). PVD (particle volume distribution) showed that natural loess particles in seawater were largely constituted of two types of particles, such as rapidly settling particles and suspended and dispersed particles for a long time. Amount of the latter was much less than that of the former.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.53-65
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• 2012

This study was focused on removal efficiency of complex (or mixed) wastewater from agricultural and industrial plant for advanced treatments by HBR-II process, that was well known to be suitable to the treatment of livestock wastewater. The main purpose of this study was intended to evaluate the applicable feasibility of the HBR-II for revamping the present activated sludge process to the advanced one. And also, the settling study including the batch typed experimental column tests was performed to evaluate the coagulation stability of organic colloidal particles in wastewater. The mid-scale plant of HBR-II process between pilot and laboratory was used for this study. As F/M ratio remains constant in the range of 0.20~0.25 $BOD_5/Kg{\cdot}MLSS/Day$, the efficiency of biological treatment increased. It has been shown that the results of biodegradation study were, for removal efficiency(%), $BOD_5$ 98.4%, $COD_{Mn}$ 92.9%, SS 97.5%, T-N 91.3%, T-P 82.3%, respectively, which were relatively higher than other processes. From this study, HBR-II process would be well applied to the biological treatment of agricultural and industrial complex wastewater.

• Tribology and Lubricants
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• v.15 no.3
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• pp.278-286
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• 1999

To predict the behavior of the intravascular micro active endoscope in the real human vascular system, a human mock circulation system was developed. The intravascular micro active endoscope which consists of micro active bending catheter and micro drug infusion catheter was driven in the velocity, Re number and temperature controlled flow. The three SMA (Shape Memory Alloy) zigzag type spring in the micro active bending catheter was heated by the electric current generated by PWM controller, and the shape memory effect made the actuator bend to any direction. The micro drug infusion catheter was driven through the inner hole of the micro active bending catheter. A mock circulation system is shaped from Ascending Arota to Femoral artery according to a human data (the data contains many vascular sizes and hydrographs of many control points). We developed a vascular model with glass and silicone tubes, and set the flow system with circulation parts, flow settling parts, and lots of valves. The heater and heat-controller was added to the How system to centre! the temperature of the How at 36.5$^{\circ}C$. The result showed that the developed intravascular micro active endoscope could be induced to any point in the vascular model.