• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.2
• /
• pp.211-219
• /
• 2016

To develop an ash separator for the solid fuel chemical looping combustion system, effects of operating variables such as solid injection nozzle velocity, diameter of solid injection nozzle, gap between solid injection line and vent line, vent line inside diameter, and solid intake height on solid separation rate and solid separation efficiency were measured and discussed using heavy and coarse particle and light and fine particles mixture as bed material in an acrylic fluidized bed apparatus. The solid separation rate increased as the solid injection nozzle velocity and the diameter of solid injection nozzle increased. However, the solid separation rate decreased as the gap between solid injection line and vent line, the vent line inside diameter, and the solid intake height increased. The solid separation efficiency was in inverse proportion to the solid separation rate. In this study, we could get high solid separation rate up to 2.39 kg/hr with 91.6% of solid separation efficiency.

• Journal of Soil and Groundwater Environment
• /
• v.18 no.5
• /
• pp.56-64
• /
• 2013

After the law has been enacted for the prevention and recovery of mining damage in 2005, efforts of remediation have been started to recover heavy metal contaminated soils in agricultural land near mining sites. As part of an effort, the upper part of cultivation layer has been treated through covering up with clean soil, but the heavy metal contamination could be still spreaded to the surrounding areas because heavy metals may be remained in the lower part of cultivation layers. In this study, the most frequently occurring arsenic (As) contamination was selected to study in agricultural land nearby an abandoned metal mining site. We applied separation technologies considering the differences in the physical characteristics of soil particles (particle size, density, magnetic properties, hydrophobicity, etc.). Based on physical and chemical properties of arsenic (As) containing particles in agricultural lands nearby mining sites, we applied sieve separation, specific gravity separation, magnetic separation, and flotation separation to remove arsenic (As)-containing particles in the contaminated soil. Results of this study show that the removal efficiency of arsenic (As) were higher in the order of the magnetic separation, flotation separation, specific gravity separation and sieve separation.

• Carbon letters
• /
• v.16 no.3
• /
• pp.215-218
• /
• 2015

Carbon micro particles with dimple patterns were produced by electro-spraying a solution of pitch in tetrahydrofuran. Particle formation depended on separation in an electrical field and volatilization of the solvent. More than 80% of the obtained carbon exhibited an average particle size of less than 50 μm. X-ray diffraction analysis suggests that the carbon with dimple patterns has increased crystallinity after heat treatment.

• Applied Science and Convergence Technology
• /
• v.24 no.5
• /
• pp.196-202
• /
• 2015

Human blood consists of 55% of plasma and 45% of blood cells such as white blood cell (WBC) and red blood cell (RBC). In plasma, there are many kinds of promising biomarkers, which can be used for the diagnosis of various diseases and biological analysis. For diagnostic tools such as a lab-on-a-chip (LOC), blood plasma separation is a fundamental step for accomplishing a high performance in the detection of a disease. Highly efficient separators can increase the sensitivity and selectivity of biosensors and reduce diagnostic time. In order to achieve a higher yield in blood plasma separation, we propose a novel fluid wing structure that is optimized by COMSOL simulations by varying the fluidic channel width and the angle of the bifurcation. The fluid wing structure is inspired by the inertial particle separator system in helicopters where sand particles are prevented from following the air flow to an engine. The structure is ameliorated in order to satisfy biological and fluidic requirements at the micro scale to achieve high plasma yield and separation efficiency. In this study, we fabricated the fluid wing structure for the efficient microfluidic blood plasma separation. The high plasma yield of 67% is achieved with a channel width of $20{\mu}m$ in the fabricated fluidic chip and the result was not affected by the angle of the bifurcation.

• Journal of Mechanical Science and Technology
• /
• v.16 no.10
• /
• pp.1336-1345
• /
• 2002

A triboelectrostatic separation system using a fluidized bed tribocharger for the removal of PVC material in the mixture of PVC/PS plastics is designed and evaluated as a function of electric field strength, air flow rate, and the mixing ratio of two-component mixed plastics. It consists of a fluidized-bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PS particles can be imparted negative and positive surface charges, respectively, due to the difference in the work function values of plastics suspended in the fluidized-bed tribocharger, and can be separated by passing them through an external electric field. Experimental results show that separation efficiency is strongly dependent on the electric Deld strength and particle mixing ratio. In the optimum conditions of 150 Ipm air flow rate and 2.6 kV/cm electric field strength a highly concentrated PVC (99.1%) can be recovered with a yield of more than 99.2% from the mixture of PVC and PS materials for a single stage of processing.

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.3
• /
• pp.306-312
• /
• 2011

In this study, we are crystallized to the low density polyethylene (LDPE) micro-particles in $n$-dodecanol solution by thermally induced phase separation(TIPS) method. The Low density polyethylene micro-particles is used in a wide variety of polymer coatings and industrial application. The utility of that for a particular application depends on a number of factors such as the particle size and distribution, and chemical composition of the materials. However, there are still needs for new methods of preparation which will provide the structure with unique sizes. The widely used processes for micro-size particles are crystallization method and thermally induced phase separation. TIPS process based on the phase separation mechanism was performed for the LDPE system which undergoes liquid-solid phase separation. Effects of various operating parameters were examined on the structure variation of the particles. Professionality, take-up speed and crystallization rate depended on temperature and concentration of polymer in solution.

• Korean Journal of Remote Sensing
• /
• v.32 no.3
• /
• pp.245-251
• /
• 2016

We present linear particle depolarization ratio at 440, 675, 870, and 1020 nm retrieved from measurements with an AERONET sun/sky radiometer at the source region of Asian dust, Dunhuang. The linear particle depolarization ratios are retrieved at the two receptor sites (Gosan and Osaka). The highest linear particle depolarization ratio of 0.34 at 1020 nm is retrieved from nearly pure Asian dust. The linear particle depolarization ratio decreased as the volume concentration of fine-mode particle increased. We can confirm that the ratio of Asian dust is changed by the value of the linear particle depolarization ratio retrieved by AERONET data.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.06a
• /
• pp.534-539
• /
• 2005

Particle image analyzer for measuring droplet size has been developed. Image processing technique was used with relaxation method. The morphological method based on partial curvature information of pre-processed images was adopted for recognition and separation of overlapped particles. The measurement results show that the present method may be reliable for the analysis of the size and distribution of droplets produced by water mist spay flow.

• Journal of Korean Society on Water Environment
• /
• v.37 no.1
• /
• pp.10-19
• /
• 2021

In the flotation process to remove microplastic (MP) particles, the attachment and separation efficiency is determined by the basic physicochemical characteristics of MP particles as well as bubbles. To evaluate the flotation characteristics of MP particles, we carried out a series of simulations using the population balance (PB) model. The initial attachment coefficient (αo) of MP particles was in the range of 0.2-0.275, and it was slightly lower than that of typical particles, such as clay, debris and algae particles, which exist in water bodies, αo, 0.3-0.4. The relative bubble number (RBN) attached to the surface of the typical number of bubbles was 0.30 and 0.32 for MP 30 ㎛ and MP 58 ㎛, respectively. In comparison, the RBN of larger MP particles (138 ㎛) was as high as 0.53. Furthermore, smaller microbubbles were required to separate properly or additional treatment needed to be applied to enhance collision and attachment efficiency since the flotation of MP particles was found to be difficult to treat as high-rate. As a result of comparing the removal rate (experimental value) of MP particles obtained from the batch-type flotation apparatus and the flotation removal rate (predicted value) of MP obtained through the PB model, the final particles by the particle size of MP overall except for the initial separation time area. With respect to the removal efficiency, the observed and predicted values were similar, and it was confirmed that the floating separation characteristics and evaluation of the MP particles through the PB model could be possible.

• Progress in Superconductivity and Cryogenics
• /
• v.22 no.2
• /
• pp.7-11
• /
• 2020

When rivers and lakes are contaminated with numerous contaminants, usually the contaminants are finally deposited on the sediments of the waterbody. Many clean up technologies have been developed for the contaminated sediments. Among several technologies dredging is one of the best methods because dredging removes all the contaminated sediments from the water and the contaminated sediments can be completely treated with physical and chemical methods. However the most worried phenomenon is suspension of fine particles during the dredging process. The suspended particle can release contaminants into water and resulted in spread of the contaminants and the increase of risk due to the resuspension of the precipitated contaminants such as heavy metals and toxic organic compounds. Therefore the success of the dredging process depends on the prevention of resuspension of fine particles. Advanced dredging processes employ pumping the sediment with water onto a ship and release the turbid water pumped with sediment into waterbody after collection of sediment solids. Before release of the turbid water into lake or river, just a few minutes allowed to precipitate the suspended particle due to the limited area on a dredging ship. However the fine particle cannot be removed by the gravitational settling over a few minutes. Environmental technology such as coagulation and precipitation could be applied for the settling of fine particles. However, the process needs coagulants and big settling tanks. For the quick settling of the fine particles suspended during dredging process magnetic separation has been tested in current study. Magnetic force increased the settling velocity and the increased settling process can reduce the volume of settling tank usually located in a ship for dredging. The magnetic assisted settling also decreased the heavy metal release through the turbid water by precipitating highly contaminated particles with magnetic force.