Jo May 29, 2026
Domestic wastewaters and industrial wastewaters from food processing industry, pulp industry, pharmaceutical and organic synthesis industries, coalmines and mines contain various inorganic and organic substances in the form of fine suspension, emulsions, colloids, etc. In particular, the microplastics contained in wastewater pose a potential threat to the environment and human health due to their small particle size, high hydrophobicity and easy adsorption of toxic substances.
There are several methods for treating wastewater containing microplastics, among which the dissolved air flotation (DAF) process using microbubbles has attracted special attention. DAF process is one of the wastewater treatment methods for accelerating gravity separation by adhering microbubbles to solid particles in wastewater and increasing the density difference between continuous and dispersed phases.
Most of the previous studies have paid a great deal of attention to the structure of DAF tanks and fluid flow characteristics, and little effort has been directed to the effect of liquid properties on flotation efficiency.
Since the objective of the DAF process is to increase the efficiency of impurity removal under constant hydraulic surface loads, it is also important to have a correct understanding of the interaction characteristics between particles to be removed, bubbles and liquid phases.
Kim Kwang Jun, a researcher at the Institute of Nano Science and Technology, has simulated the process of dissolved air flotation (DAF) to remove microplastics from various wastewaters by the computational fluid dynamics (CFD) method.
First, he injected a solution with a resin particle concentration of 0.2 g/L at a flow rate of 20 mL/min. Then, he injected a solution with a water-to-microbubble volume ratio of 4:1 at a flow rate of 300 mL/min. The simulation results showed that the kinematic and distribution characteristics of the resin particles and microbubbles were in good agreement with the experimental results.
Based on the simulation system to analyze the behavior of particles in flotation solutions, he evaluated the flotation performance by varying the concentration of NaCl solution and the pH value of 10-2 M salt solution. The calculation results showed that the flotation performance improved with increasing NaCl concentration and pH, and the concentration of NaCl had a greater effect.
These results provide some basic information for designing industrial wastewater treatment processes for removing microplastics from wastewater of different properties.
For further details, you can refer to his paper “CFD Simulation of DAF processing for removal microplastic in different flotation solution” in “Water Science & Technology” (SCI).
...
Jo May 28, 2026
Quick-freezing is an essential process for long-term storage and long-range transport of fish. With the development of fish processing, it is very important to realize automatic line of fish quick-freezing processes and increase quick-freezing capacity.
Therefore, wheeled mobile loaders (WMLs) are important for automatic line of fish processing.
Pak Myong Nam, a researcher at the Institute of Robotics, evaluated the static stability of a newly designed WML in consideration of its structure, working principle and overturning moment. Then, he analyzed the effect of parameters on its dynamic stability by using ADAMS and conducted an analysis of variance (ANOVA) to optimize its design parameters.
The results show that dynamic analysis of collision force acting on the wheels can be effectively used to improve the vibration characteristics of WMLs, and that dynamic stability simulations and design optimization for all the working processes can reduce vibration and eliminate overturning tendency.
If more information is needed, please refer to his paper “Dynamic Stability Simulation and Design Optimization of the Wheeled Mobile Loaders for Automatic Line of Fish Processing” in “Journal of Vibration Engineering & Technologies” (SCI).
...
Jo May 27, 2026
Scandium has been widely used as alloy material in the fields of aerospace, optics, transport, etc. Scandium is an effective grain refiner and it increases the recrystallization temperature in different alloys with its unique property.
The amount of Sc in the earth’s crust is 22ppm on average. Scandium is found in small amounts in other metal ores. Minerals containing Sc include monazite, bastnasite, ilmenite, rutile, bauxite, uraninite, etc.
Several researchers have employed different methods for determining the amount of scandium. These methods have several disadvantages like complex pretreatment procedure and long pretreatment time.
An Hyo Song, a researcher at the Institute of Analysis, has proposed a new method for determining scandium content in the sedimentary rock based apatite on the continental shelf using Ti as an internal standard element by wavelength dispersive X-ray fluorescence spectrometry (WDXRFS) technique, and established a sample preparation procedure and the parameters of equipment.
RSD of the proposed method was less than 5%. The average scandium content in the total survey area was 25ppm.
The proposed WDXRF technique can be applied to the studies of different geological materials containing less than 1% of scandium.
For more information, you can refer to his paper “Analytical Method for Determination of Scandium Distribution Characteristics in Sedimentary stratum on the Continental shelf by Wavelength Dispersive X-ray Fluorescence Spectrometry” in “Journal of X-ray science and technology” (SCI).
...
Jo May 26, 2026
Inorganic nanoparticles have been dispersed in resin blends to prepare many nano-composite resin materials. This hybrid material exhibits the combined properties of inorganic nanoparticles such as mechanical strength, elasticity and thermal stability, and of the processibility and flexibility of organic polymers.
Previous studies reported that the addition of SiO2 nanoparticles to PVC resin leads to enhanced sound resistance, and adding TiO2 nanoparticles to PVC resin can enhance its whiteness and prevent UV degradation of resin products. However, there are very few polymer materials with both SiO2 and TiO2 nanoparticles.
Addition of SiO2 and TiO2 nanoparticles together to the PVC resin will result in its lower degradation of by UV light and better resistance to degradation than adding either of them alone.
For the purpose of using PVC nano-composite as a raw material instead of rubber that is often used as a conveying belt material, Jang Un Hui, a researcher at the Institute of Analysis, prepared new nano-composites by mixing SiO2 and TiO2 nanoparticles with PVC resin, and carried out differential scanning calorimetry (DSC) under non-isothermal conditions in order to investigate the crystallization behavior and kinetics of the newly prepared PVC/Nano SiO2-TiO2 composites.
The analysis results showed that the crystallization behavior of PVC/Nano SiO2-TiO2 composite with 3-5% SiO2 and TiO2 nanoparticles is good.
For more information, please refer to her paper “Study on the non-isothermal crystallization kinetics of PVC/NanoSiO2-TiO2 composite resin by DSC” in “Journal of Polymer Research” (SCI).
...
Jo May 25, 2026
The FFC method has been widely used to prepare metal powders and alloy powders from their oxides in molten salts.
Many researchers have employed several electrochemical techniques to study proper mechanisms and experimental conditions for it.
However, there have been no studies reported on the method of preparing Dy-Fe alloy powders from Dy2O3-Fe2O3 mixtures in molten CaCl2 by the FFC method.
Kim Pyong Hun, a section head at the Institute of Analysis, has conducted a study to prepare Dy-Fe alloy powders from Dy2O3-Fe2O3 mixtures in molten CaCl2 by the FFC method.
In the Dy2O3-Fe2O3 mixtures for his study, the ratio of Dy to Fe was 1:2. He used the cyclic voltammetry and constant voltage electrolysis.
Three cathodic current peaks were observed in the cyclic voltammetric curves, which explains that the reduction mechanism of Dy2O3–Fe2O3 mixtures goes through several steps.
The suitable electrolysis conditions for the preparation of alloy DyFe2 from Dy2O3–Fe2O3 mixtures in molten CaCl2 were 2.8 V, 850 ℃ and 20 h.
You can find more information in his paper “Preparation of Dy-Fe Alloy Powders from Dy2O3–Fe2O3 Mixtures in Molten CaCl2 by FFC Method” in “Transactions of the Indian Institute of Metals” (SCI).
...
Jo May 24, 2026
Whenever new viruses came into being, mankind has acquired various knowledge including their nature and transmission, and the symptoms and treatment of the diseases, and made vaccines and established treatment tactics.
One of the important issues to cope with infectious diseases is prediction of virus transmission by mathematical modeling. Based on mathematical modeling, it has been widely studied in the world. Mathematical modeling for predicting future epidemics makes it possible to predict the number of medical personnel and beds, medical equipment, medical drug supplies, etc. that are needed to prepare at hospitals. It also helps find a suitable approach for medical service through simulations.
The parameters included in this mathematical model are the key elements that characterize the epidemic of diseases. Therefore, it is important to set the parameters realistically.
Kim Ju Hyong, a researcher at the Faculty of Biomedical Engineering, proposed a method for determining the parameters involved in mathematical models of epidemics using genetic algorithms, and verified its validity.
To test the validity of this method, he built a SEIHRD model and compared the accuracy of the simulation with unknown parameters determined when the underlying data were prepared in various forms.
The results show that the proposed method is a recursive one for simply determining unknown parameters in a mathematical model study considering the spread of epidemics.
For more information, please refer to his paper “A method to determine the unknown parameters of mathematical model of epidemic transmission by genetic algorithm” in “Network Modeling Analysis in Health Informatics and Bioinformatics” (SCI).
...