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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Jo Jan 16, 2026
Point-type smoke sensors detect fire through sensor signals that are changed by smoke, which occurs early from the fire. However, the drawback of these smoke sensors is the drift of sensor signals due to the sensitivity to environmental changes. This can be the cause of occasional false alarms.
The first reason for sensor signal change in smoke sensors is seasonal changes in temperature and humidity. Secondly, in the case of an ionic smoke sensor, the accumulation of dust layers on the surface of radiation source decreases the ion current and the leakage of current between the electrodes causes the sensor signal to change. Inherent noise caused by the uncertainty of the radioactive decay for ionization is another reason, which is inversely proportional to the square root of the radioactivity. Lastly, the radiation sources used for the ionic smoke sensor are not uniform, so the sensitivities and signals of the sensors are also different, which also degrades the accuracy of fire alarm in a fire monitor based on a fixed threshold.
By these factors, sensor signals tend to increase or decrease slowly with time. If these signals are higher than a fixed threshold already set, the false alarm can be heard in the absence of fire, and if they are lower, they may generate the alarm late for real fires or may not generate the alarm at all. Therefore, smoke sensors or fire monitors need to adjust the threshold actively according to the sensor signals.
Jo Jin Song, a researcher at the Institute of Analysis, designed and verified a compensation algorithm that can automatically adjust the threshold for point-type smoke sensors or fire monitors.
The algorithm does not fix the threshold that is the criterion for identifying fire presence, but it can adjust it gradually to the change of sensor signals to improve the accuracy of alarm.
This algorithm can be applied to almost all point-type smoke sensors or fire monitors for active fire detection.
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