Jo Jun 24, 2026
Determination of uranium is very important for effective use of seawater. Uranium is the most stable of all the elements in the ocean. The concentration and pH of uranium in the seawater differ a little according to the region and the depth, but the averages are 3.3×10-6g/L and 8, respectively.
Yun Chol Hun, a researcher at the Institute of Analysis, has reported a new combined method for the determination of trace uranium in seawater.
First, he added ferric chloride to 1L of seawater sample and adjusted the pH to 4. Then, he placed the solution at 80℃ for 30 min to coprecipitate uranium with iron hydroxide. After that, he dissolved the precipitate in nitric acid and electrodeposited it in EMIMBF4 to determine uranium by ICP-OES.
He evaluated the coefficient of diffusion (D) of electrodeposition of U(VI) on platinum electrode in EMIMBF, which was 3.31×10−9cm2/s. The electrochemistry experiments indicated that the reduction of U(VI) at platinum electrode in EMIMBF4 was a quasi-reversible single step two-electron transfer. The percent of chemical coprecipitation recovery of U(VI) was 98.9% and the recovery in electrodeposition was 99.5%.
For more information, please refer to his paper “Determination of uranium in seawater using chemical coprecipitation-ionic liquid electrodeposition by ICP-OES” in “Journal of Radioanalytical and Nuclear Chemistry” (SCI).
...
Jo Jun 23, 2026
Flooding is a major hazard in rural and urban areas worldwide and accounts for a large portion of life and economic losses caused by natural disasters. Non-structural measures to reduce flood damage are very economical compared to structural measures.
Accurate and rapid prediction of flood inundation extent is an important task to reduce flood risk. Non-structural measures make it possible to predict inundation areas by combining accurate flood forecast and real-time observations.
Seeded Region Growing (SRG) is widely used for flooded area extraction. The seeded region growing method requires a large amount of memory space because the entire DEM dataset is initially assigned to memory, which cannot be implemented with the existing PC’s memory space. Furthermore, the limited use of computer memory space prevents the implementation of computational continuity during flood inundation analysis. When there is a large area of inundation extent and a large amount of DEM data, many recursive operations required by the seeds region growing algorithm reduce computational efficiency and can cause stack overflow due to the large data. For this reason, the use of seeded region growing algorithm applied to flood inundation prediction is limited.
Ko Song Hwan, a researcher at the Institute of Information Technology, proposed an isosurface region growing method to reduce floodplain extraction time using high resolution DEM, and a locally detailed grid SRG method to solve the problem of different inundation area by different DEM resolutions.
On a contour map with small contour intervals, if all the intersected points on the two adjacent contour lines are submerged, it can be seen that the isosurface between those contours is completely submerged. The isosurface region growing method can reduce the time for flood inundation extent extraction more than the seeded region growing method as it extends inundation areas by isosurface along the contour tree. The locally detailed grid SRG method divides the cells intersecting with top contours of the terrain barrier into small size cells. Then, a seed point is selected on the isosurface which is not completely submerged and the seeded region growing method is applied. This method can solve the problem of distorted diffusion of inundation areas around the terrain barrier.
Comparing the inundation area extraction time by the seed area growth method with that by the contour area growth method and the detailed grid SRG method, he found that the proposed method consumes less computation time.
His paper “Flood inundation extent extraction using isosurface region growing and locally detailed grid SRG” was presented at “2025 10th International Conference on Intelligent Information Technology (ICIIT 2025)”.
...
Jo Jun 22, 2026
Moving packed bed drying can reduce the costs of transportation and storage of products. Grain dryers can be categorized into fixed bed dryers, fluidized bed dryers, rotary kilns and moving bed dryers.
A packed moving bed dryer using the air of low temperature (100℃) was developed in order to get large amounts of grain with required moisture in a given time.
Jon Chol Jin, a section head at the Faculty of Thermal Engineering, has proposed a steady moisture equation for analysing a grain drying process at a packed moving bed, and carried out a numerical simulation based on the governing equations of the grain energy equation.
The simulation results showed that the grain moisture grows lower when the moving velocity of the packed bed becomes lower.
The present model can be applied to predicting the positional distribution of physical quantities such as temperatures of air and grains as well as the relative humidity of air and the moisture content of grains in an arbitrarily-shaped packed moving grain dryer.
For further details, please refer to his paper “Steady State Analysis for Heat and Mass Transfer of Moving Grain in Cylindrical Dryer” in “Proceedings of KUTIC-2025”.
...
Jo Jun 21, 2026
Tracking control is a very important and practical problem in the motion control of mobile robots. Tracking control can be divided into trajectory tracking control and path tracking control. In trajectory tracking control, the motion path of a mobile robot is given as a function of time, and in path tracking control, it is given by easily realizable geometrical parameters such as arcs. Trajectory tracking control is necessary when a robot should be in a certain position at a certain time. Path tracking control is appropriate when a robot has to move along the path given by the geometrical parameters at a constant speed.
Several control methods have been proposed to realize trajectory tracking control of mobile robots. In the previous literature, there has been a lot of research on the methods for achieving trajectory tracking control of robots by improving the speed control performance of individual actuators of mobile robots, but there is no report on improving the trajectory tracking performance of differential-driven mobile robots by compensating the errors of actuators.
Kim Yong Il, a section head at the Faculty of Mechanical Science and Technology, has proposed a method of designing a cross-coupled controller to improve the trajectory tracking performance by compensating the errors of actuators.
He implemented the PID control of individual motors and the cross-coupling control for error compensation to reduce trajectory tracking errors.
To verify the effectiveness of the proposed method, he carried out a simulation by MATLAB/Simulink. The experimental results showed that the trajectory tracking error could be significantly reduced by the proposed method.
You can find the details in his paper “Trajectory Tracking Control of a Differential-Driven Mobile Robot using a Cross-Coupled Controller” in “Proceedings of KUTIC-2025”.
...
Jo Jun 19, 2026
Today, as energy resources are depleted and environmental pollution is a problem worldwide, the development of clean energy and more efficient use of the existing energy resources has become very important in the automotive industry. What is the most important to solve this problem is to design and develop engines with high power output and fuel economy and low level of harmful gas emission.
Air movement inside the diesel cylinder has a crucial effect on the formation of mixtures and combustion processes, thus affecting the dynamical character, economy, combustion noise, and emissions of harmful gases of diesel engines, too. Swirl ratio has a great effect on the formation of fuel-air mixtures and combustion process in the cylinder. This encouraged many studies to optimize intake channels.
However, there are some problems in the literature. Generally, the effect of swirl ratio has not been considered in detail because the flow rate is kept constant when considering the effect of swirl ratio on the engine combustion process. In addition, spiral intake channels are introduced for cylinder head intake channels, which is difficult to implement because the demand for intake tube manufacture is too high.
On the basis of a detailed analysis of the effect of intake swirl on the combustion characteristic of a 12hp direct injection diesel engine, Ho Pong Guk, a section head at the Faculty of Mechanical Science and Technology, improved the combustion characteristics of engines by modifying the cylinder head intake channel to provide high swirl ratio with high flow rate.
The proposed method might be useful in practice because it is not difficult to apply and it provides the swirl ratio suitable for combustion.
For further details, you can refer to his paper “Geometry Determination of Cylinder Head Intake Channel Considering the Effect of Swirl Ratio on Combustion Process in a Direct Injection Diesel Engine” in “Proceedings of KUTIC-2025”.
...
Jo Jun 18, 2026
The peel test is widely used for material selection and quality control testing. To learn the properties and adhesion characteristics of material, the test conditions and analytical methods should be used appropriately. The purpose of a peel test is to obtain the main property of the interface, GC, which is usually called fracture energy. The value of fracture energy, GC, should be the main characteristic for the evaluation of bond strength.
There have been many attempts to calculate the fracture energy GC, which reflects bond properties. However, the authors mostly focused on the case of a joint with substrates as adhesives.
Choe Kyong Hyok, a section head at the Faculty of Mechanical Science and Technology, has proposed a method for determining the fracture energy of a polyethylene thermal joint and determined the fracture energy values for several joints.
He performed a finite element analysis to determine the fracture energy values from the peel test data. He used a node release technique to model the crack propagation through the interface of the two membranes. When performing finite element modeling, he accurately reflected the mechanical properties of polyethylene to increase the accuracy of the simulation.
For more information, please refer to his paper “Method for Determining Fracture Toughness of Polymer Adhesive Interfaces Considering Viscoelastic Loss” in “Proceedings of KUTIC-2025”.
...