Jo Jan 23, 2026
With decades of continuous coal mining, the mining conditions of coal seams are becoming increasingly unfavorable. Coal seams generally include thick coal seams, thin coal seams, uncomplex coal seams and complex coal seams, with different thicknesses and shapes.
Some coal seams have high thickness and inclination and complicated orientation. In such coal seams, it is difficult to use mining machinery such as a coal cutter-loader. To make more effective use of underground resources, it is necessary to mine not only suitable coal seams but also complex coal seams, that is, those for which machinery and equipment were unable to be used in the past because of poor mining conditions.
However, there has been little research on coal mining in coal seams with complex morphology, with high variation in thickness and inclination angle of coal seams.
Pak Jang Hyok, a researcher at the Faculty of Mining Engineering, has proposed a novel coal mining method (a diagonal collapse coal mining method), which can be applied to difficult-to-machine conditions due to the high variations of thickness and inclination angle of coal seams.
This is the method of coal excavation by drilling up tunnels with a diagonal angle, and the transportation of coal in the face is carried out by a chute without using special transport equipment.
The research results show that this method is best suited to apply to complex coal seams varying in inclination angles above 15°, and it can also be applied to coal seams varying in inclination angles below 15°, but it is preferable to take into account economic indices.
For more information, please refer to his paper “Numerical Simulation for the Determination of the Dip Angle of a Diagonal Collapse Coal Mining Method by EDEM Under Complex Anthracite Seam Conditions” in “Advances in Civil Engineering” (SCI).
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Jo Jan 22, 2026
Promoting seed germination is important for increasing grain production. It requires increasing tolerance to various types of stresses including drought and the disease tolerance of crops.
Wheat is one of the three major field crops along with maize and rice worldwide. In temperate regions, spring wheat sowing is mostly carried out in March and April. This period represents the seed dormancy due to low average ambient temperatures of 8–15 °C and low soil water content due to drought. Therefore, it is important to break the dormancy of wheat seeds, increase the germination rate of seeds, promote growth, and improve drought tolerance.
Choe Hak Chol, a researcher at the Faculty of Physics, evaluated the effects of the gliding arc discharge (GAD) plasma-treatment on the germination of dormant wheat seeds and old seeds at low ambient temperature.
The GAD plasma promoted the germination of dormant wheat seeds and old seeds at 10 °C. For wheat seeds treated by GAD plasma with a power of 400W, the germination potential, the germination rate, the percentage of germination and the sprout length showed clear increasing trends compared to untreated ones. The positive germination effects similar to the above were observed even for old seeds kept at 25 °C.
You can find more information in his paper “Gliding arc discharge plasma treatment for promoting germination of wheat seed at low ambient temperature” in “Journal of Vacuum Science and Technology A” (SCI).
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Jo Jan 21, 2026
Recently, many numerical and experimental studies on the mechanical behavior of functionally graded (FG) structures have been carried out as they are widely used in various fields of engineering due to their benefits such as high stiffness, light weight and high thermal resistance.
Sin Chol Nam, a section head at the Faculty of Mechanical Science and Technology, has proposed a meshfree Jacobi-radial point interpolation (Jacobi-RPI) method for the dynamic analysis of a functionally graded elliptical shell with varying thickness (FGESVT) in supersonic flow and thermal environment.
He assumed the material properties of FGESVT to vary along the direction perpendicular to the bottom surface. He considered the thermal stress due to the variation of environmental temperature by introducing the nonlinear part of the Green–Lagrange strain. He constructed a meshfree shape function by combining the radial basis with Jacobi polynomials with fast convergence, numerical stability and high accuracy. He expanded the displacement components of the FGESVT by using the meshfree Jacobi-RPI shape function. He obtained the equations of motion of the closed FGESVT by coupling the equations of several open shells.
He has validated the accuracy and reliability of the proposed method through a sufficient number of numerical studies for the free vibration and dynamic response analysis of open and closed FGESVT.
For more details, please refer to his paper “A meshfree method for thermodynamic analysis of functionally graded elliptical shell with varying thickness in supersonic flow” in “Archive of Applied Mechanics” (SCI).
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Jo Jan 20, 2026
The use of known model information in the design of an active disturbance rejection controller reduces the magnitude of the “total disturbance” and consequently improves the control performance.
Based on Takagi–Sugeno (T-S) fuzzy modeling, Choe Hak Jin, a researcher at the Faculty of Metallic Engineering, proposed a new method for incorporating the known nonlinear dynamics of the plant into a linear active disturbance rejection controller (LADRC),
In order to evaluate the effectiveness of the proposed method, he performed simulations of a cart inverted pendulum.
The simulation results show that the estimation burden of the extended state observer is reduced and the control performance is improved in the proposed method than in the conventional model-assisted LADRC that can incorporate only linear model information, and that the proposed cascade control scheme has good disturbance rejection, transient response and robustness at the same time.
If further information is needed, please refer to his paper “A cascade control scheme with T-S fuzzy model-assisted linear active disturbance rejection controller for position tracking of cart inverted pendulum” in “International Journal of Dynamics and Control” (SCI).
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Jo Jan 20, 2026
The viscosity of slag is a very important factor in understanding the rate of metal-slag chemical reactions and the mass transfer taking place in the pyrometallurgy process. It is also vital for ensuring stable operation of metallurgical furnaces. Therefore, accurate prediction of the viscosity of slag is of great importance not only for the operation stability and productivity in the pyrometallurgy process but also for high yield.
Up to now, many researchers have carried out various viscometric experiments of slag, and many models have been developed to estimate its viscosity. However, the previously developed slag viscosity prediction models are mostly for solid-free slag.
Since most metallurgical slag necessarily contains MgO, it is very important to develop a model for predicting the viscosity of CaO–SiO2–Al2O3–MgO system slag.
Ro Tae Song, a researcher at the Faculty of Metallic Engineering, has proposed a viscosity prediction model of CaO–SiO2–Al2O3–MgO system slag using the multi-gene genetic programming (MGGP).
The proposed viscosity model is a simple algebraic equation with varying basicity, Al2O3 content, MgO content and temperature of slag. Furthermore, the average relative error between experimental data and the calculated values using the model is 25.10%, which is comparatively small.
For more information, please refer to his paper “Viscosity Prediction of CaO–SiO2–Al2O3–MgO System Slag Using MGGP” in “Transactions of the indian institute of metals” (SCI).
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Jo Jan 18, 2026
Now cyanidation is the main method for producing gold from gold ore/concentrate.
It is well-known that gold in ore/concentrate is dissolved in the form of gold-cyanide complex by the action of cyanide and oxygen. During cyanidation, copper in the ore/concentrate readily reacts with cyanide to form stable cyanide complexes and under ordinary cyanidation conditions Cu(CN)32- is the dominant species in leach solution. Thus, the recovery of copper as well as cyanide from gold-plant wastewater will offer economic benefit.
AVR (acidification-volatilization-regeneration) technology, SART (sulfidization-acidification-recycling-thickening) process, electrowinning, membrane technologies, etc. have been developed to recover cyanide and/or copper, but each of these technologies has advantages and limitations and there is no universal method. Among these, AVR process has been used in industry owing to its simple principle and high effectiveness and robustness.
Kim Yong Il, a researcher at the Faculty of Metallic Engineering, evaluated sulfuric acid baking-leaching process to recover copper from precipitate containing Cu of 44.53 wt %, Fe of 5.56 wt % and S of 16.81 wt %, which comes from cyanidation wastewater treatment process by AVR (acidification-volatilization-regeneration) technology in a gold plant.
The experimental results showed that by acid baking under following conditions of 250℃, 60 min and the ratio of H2SO4 to copper precipitate 2.4:1, ~98.5 wt % copper was released to the leach solution, and that the leachate containing Cu and Fe can be sent to the conventional SX-EW process to produce electrolytic copper.
You can find the details in his paper “Acid Baking-Leaching Process for Treatment of Copper Precipitate from AVR Process” in “Russian Journal of Non-Ferrous Metals” (SCI).
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