• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.65-70
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• 2010

The distillation rate on LiCl-KCl eutectic salt under different vacuums from 0.5-50 mmHg was first investigated by using both a non-isothermal and a isothermal thermogravimetric (TG) analysis. Based on the non-isothermal TG data, distillation rate equations as a function of the temperature could be derived. Calculated flux by these model flux equations was in agreement with the distillation rate obtained from isothermal TG analysis. A distillation rate of $10^{-4}-10^{-5}$ mole $cm^{-2}sec^{-1}$ is obtainable at temperatures less than 1300K and vacuums of 0.5-50 mmHg. About a 99% salt distillation efficiency was obtained after an hour at a temperature above 1150 K under 50 mmHg in a small scale distillation test system. An increase in the vaporizing surface area is relatively effective for removing residual salt in the remaining particles, when compared to that for the vaporizing time. Over 99.95% of total distillation efficiency was obtained for a 1-h distillation operation by increasing the inner surface area from $4.52cm^2$ to $12.56cm^2$.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.141-155
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• 2017

In the present paper, we investigated the development status of precipitated calcium carbonate (PCC) production using steel slag, which is one of mineral carbonation (MC) technologies, from the standpoint of $CO_2$ utilization. Principle, feature, and global and domestic development status of the mineral carbonation technology were discussed together with the overview of the production method and market of PCC. Mineral carbonation is known as stable and environmentally-friendly technology enabling economical treatment of industrials wastes. Typically, PCC is produced by the reaction of $CO_2$ with supernatant solution after Ca extraction from steel slag followed by the separation of solid and liquid. The development status of MC using steel slag is at the pilot stage (Slag2PCC at Aalto University), and there remains the process economics improvement for commercialization. Key technologies for the further development are efficient extraction of Ca ions from steel slag including impurities removal, valorization of PCC via shape and size control, usage development and value-addition of residual slag, and optimization of reaction conditions for continuous process setup, etc.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.17-23
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• 2016

In the future network such as Internet of Things (IoT), the number of computing devices are expected to grow exponentially, and each of the things communicates with the others and acquires information by itself. Due to the growing interest in IoT applications, the broadcasting in Opportunistic ad-hoc networks such as Machine-to-Machine (M2M) is very important transmission strategy which allows fast data dissemination. In distributed networks for IoT, the energy efficiency of the nodes is a key factor in the network performance. In this paper, we propose a fuzzy logic based probabilistic multi-hop broadcast (FPMCAST) algorithm which statistically disseminates data accordingly to the remaining energy rate, the replication density rate of sending node, and the distance rate between sending and receiving nodes. In proposed FPMCAST, the inference engine is based the fuzzy rule base which is consists of 27 if-then rules. It maps input and output parameters to membership functions of input and output. The output of fuzzy system defines the fuzzy sets for rebroadcasting probability, and defuzzification is used to extract a numeric result from the fuzzy set. Here Center of Gravity (COG) method is used to defuzzify the fuzzy set. Then, the performance of FPMCAST is evaluated through a simulation study. From the simulation, we demonstrate that the proposed FPMCAST algorithm significantly outperforms flooding and gossiping algorithms. Specially, the FPMCAST algorithm has longer network lifetime because the residual energy of each node consumes evenly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.513-519
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• 2019

Typically, contaminated sediments cause clogging of the drain pipe, which increases the residual water pressure in the drain pipe; this study constructed a system for improving drainage efficiency of tunnels by reducing physical and chemical obstructions through ultrasonic energy generated by a PVDF film. The developed hybrid drainage system utilized a PVDF material film fused with an existing drainage tunnel and maintenance system resulting in the ability to initialize the reverse piezoelectric effect, which was evaluated through an on site application. In order to investigate the maintenance performance of the tunnel drainage system, contaminated sediments were simulated in a drainage pipe to test the effect of ultrasonic conditions on drainage efficiency in the laboratory. As a result of applying the developed portable equipment, the ultrasonic energy was generated for about 20 minutes resulting in a reduction of 74.62% of the contaminated sediments and improving drainage efficiency. From the tunnel, acoustic pressure measurements were taken to calculate the response rate while taking into account the laboratory results. In addition, PVDF film was attached to the transverse and longitudinal side of the drainage pipes where contaminated sediments occur most often in the field tunnel. these calculations show contaminant removal was 90% effective.

• Resources Recycling
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• v.32 no.6
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• pp.3-9
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• 2023

Separation of LED packages from PCBs and analysis of the adhesive components was conducted to enhance the recycling potential of LED modules. LED package was separated from PCBs using heat treatment under optimal conditions: temperature of above 250 ℃ and time of 20 minutes. The separation equipment can be established using a hot air injector with controlling the rotational speed of the internal screw. The separation efficiency of each type of substrate (aluminum and glass fiber) was investigated with the thickness range of the adhesive materials (0.25-0.30 and 0.30-0.35 mm). Under the optimal conditions, the efficiency can reach to 97.5% for both types of substrates with adhesive materials of thickness 0.25~0.30mm. Characterization of the residual adhesive substances from the separated LED package and PCB using microwave digestion and ICP analysis showed that the residue contained of 95% of Sn, less than 5% of Cu and Ag.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.77-84
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• 2017

Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.39-52
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• 2007

Quantitative analysis on release behavior of the $^{85}Kr\;and\;^{14}C$ fission gases from the spent fuel material during the voloxidation and OREOX process has been performed. This thermal treatment step in a remote fabrication process to fabricate the dry-processed fuel from spent fuel has been used to obtain a fine powder The fractional release percent of fission gases from spent fuel materials with burn-up ranges from 27,000 MWd/tU to 65,000 MWd/tU have been evaluated by comparing the measured data with these initial inventories calculated by ORIGEN code. The release characteristics of $^{85}Kr\;and\;^{14}C$ fission gases during the voloxidation process at $500^{\circ}C$ seem to be closely linked to the degree of conversion efficiency of $UO_2\;to\;U_3O_8$ powder, and it is thus interpreted that the release from grain-boundary would be dominated during this step. The high release fraction of the fission gas from an oxidized powder during the OREOX process would be due to increase both in the gas diffusion at a temperature of $500^{\circ}C$ in a reduction step and in U atom mobility by the reduction. Therefore, it is believed that the fission gases release inventories in the OREOX step come from the inter-grain and inter-grain on $UO_2$ matrix. It is shown that the release fraction of $^{85}Kr\;and\;^{14}C$ fission gases during the voloxidation step would be increased as fuel burn-up increases, ranging from 6 to 12%, and a residual fission gas would completely be removed during the OREOX step. It seems that more effective treatment conditions for a removal of volatile fission gas are of powder formation by the oxidation in advance than the reduction of spent fuel at the higher temperature.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.684-689
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• 2012

Poly(acrylic acid) (PAA) microspheres is one of the widely-used polymeric materials for the bio-field application and the electric materials. For the synthesis of PAA microspheres, the polymerization technique using surfactants is applied. After the synthesis, the purification and separation processes are required for the removal of surfactant. When general organic solvents were used, many problems, such as huge amount of waste solvent, additional separation processes, and the possibility of residual media, were occurred. Thus, High-pressure Soxhlet extraction using liquid $CO_2$ was developed to solve these problems. In this study, High-pressure Soxhlet extraction of the synthesized PAA microspheres using liquid $CO_2$ was conducted for the removal of Monasil PCA which is used for the dispersion polymerization of acrylic acid in compressed liquid Dimethyl ether (DME). The morphology of the extracted PAA particles was checked by field emission scanning electron microscopy (FE-SEM) and the residual concentration of Monasil PCA was analyzed by inductively coupled plasma - Optical Emission Spectrometer (ICP-OES). For studying the effect of the solvent effect, Soxhlet extraction was conducted using n-hexane, liquid DME, and liquid $CO_2$. In case of n-hexane, some extracted PAA microspheres were produced. However, deformation was also occurred due to the high thermal energy of n-hexane vapor. Liquid DME could not remove Monasil PCA. When using liquid $CO_2$, the extracted PAA microspheres which were free for the residual solvent were produced without deformation. For finding the optimum operating condition, high-pressure Soxhlet extraction was conducted for 8 hours with changing the temperature of reboiler and condenser. When the extractor temperature is $19.6{\pm}0.2^{\circ}C$ and the pressure is $51.5{\pm}0.5$ bar, the best removal efficiency was obtained.

• Journal of Powder Materials
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• v.21 no.4
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• pp.251-255
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• 2014

In this study, we optimized dissolution the dissolution conditions of porous amorphous powder to have high specific surface area. Porous metallic glass(MG) granules were fabricated by selective phase dissolution, in which brass is removed from a composite powder consisting of MG and 40 vol.% brass. Dissolution was achieved through various concentrations of $H_2SO_4$ and $HNO_3$, with $HNO_3$ proving to have the faster reaction kinetics. Porous powders were analyzed by differential scanning calorimetry to observe crystallization behavior. The Microstructure of milled powder and dissolved powder was analyzed by scanning electron microscope. To check for residual in the dissolved powder after dissolution, energy dispersive X-ray spectroscory and elemental mapping was conducted. It was confirmed that the MG/brass composite powder dissolved in 10% $HNO_3$ produced a porous MG granule with a relatively high specific surface area of $19.60m^2/g$. This proved to be the optimum dissolution condition in which both a porous internal granule structure and amorphous phase were maintained. Consequently, porous MG granules were effectively fabricated and applications of such structures can be expanded.

• Journal of the Korean Dietetic Association
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• v.8 no.2
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• pp.175-184
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• 2002

This study is to investigate consequent nutrient intake status, influence of body mass index(BMI), and fat distribution on the silk amino peptide(SAP) and dietary fiber supplementation. During 2 months of this research (January to March, 2002), 45 women aged 20yr – 30yr (average age 24.6yr) were selected as subjects. Nutrient intake was investigated by questionnaire, 24-hr recall method. Antropometric assessments of the subjects were investigated by SBIA method(Segmental bioimpedance assay, In body 3.0). The results are as follows: mean body weight 57.7kg, mean body height 161.9cm mean BMI 22.0, and mean food habit score was 8.47. Defecation frequency was increased by dietary fiber supplementation. Frequency of pain during defecation was significantly decreased by dietary fiber supplementation (p<0.01). Feeling of residual feces was significantly improved by dietary fiber supplementation(p<0.001). Status of energy and carbohydrate intakes significantly decreased after dietary fiber supplementation(P<0.05). Body fat and WHR(waist hip ratio) significantly decreased after dietary fiber supplementation(P<0.001), and percent body fat was decreased by dietary fiber supplementation, significantly(P<0.05). Above results of this study show that dietary fiber-added routine diet improves defecation condition, and lessens body fat, percent body fat without losing body muscle. Especially, declination of abdominal fat and WHR were notable. That meant decreased risk factor.