Jo Jun 15, 2023
A research team led by O Kyong Ryol, a section head at the Nano Physics Engineering Institute, has developed low-cost ceramic membranes.
Thanks to their unique advantages such as high separation efficiency, excellent thermal and chemical stability and low energy consumption, ceramic membranes have found wide application in gas separation and water purification, and in foodstuff, pharmaceutical and chemical industries.
A ceramic separation membrane is considered as a compound of gradually smaller porous materials, which generally consists of several thin separation layers on a porous support.
In the past years, most ceramic membranes were fabricated as porous ceramic supports with materials such as Al2O3, ZrO2 and SiC or their composites. However, both expensive starting materials and high cost of production processes restricted their extensive applications in industrial fields.
In order to reduce the fabrication cost, they have developed natural kaolin-based ceramic membranes.
Among these porous mineral-based materials, porous mullite ceramics have superior advantages such as good chemical and thermal durability, low expansion coefficient and excellent mechanical properties. These characteristics put them in use as ceramic membrane supports and catalyst supports.
For improvement of the porosity of supports, they are generally prepared by adding pore-forming agents such as corn starch and graphite, but these methods cost a lot and have some defects.
Therefore, as an attempt to solve such problems, they prepared low-cost porous mullite ceramic membrane supports with 2nm pores by extrusion and reaction sintering, with natural mineral kaolin as raw material and Al(OH)3 as a pore-forming agent.
Low-cost porous ceramic membranes are useful filtration components in a number of applications fields, and they will find use in removing contaminants of several micrometers in size down to nanometer range from various fluids.
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Jo Jun 14, 2023
Kang Suk Yong, a researcher at the Faculty of Management of Industrial Economy, has presented a method of assessing rational alternatives of coal separation by DEA.
It is important to stipulate and follow proper assessment procedures for selecting a suitable coal separation plan by DEA in coal mines.
The procedure she has proposed is as follows.
First, a target should be set up and DMU (decision-making unit) be selected.
The target is for proper evaluation of coal separation alternatives. The factors affecting the attainment of the target should be discovered before an analysis of the evaluation object with the target on the centre. Then, the boundaries of DMU and the qualitative and quantitative relationship between them should be determined.
Second, an assessment index system should be determined.
In DEA, evaluation of relative effectiveness for every separation alternative should be made mainly by the input and output assessment indices of each DMU.
Third, a DEA model should be solved.
The solution is for obtaining the assessment results of each DMU.
Finally, results should be analysed.
The solution result of a DEA model makes it possible to attain the optimal DMU to minimize investment and operation cost in coal mines and maximize economic effectiveness at the same time.
Selecting a coal separation alternative by DEA enables us to take measures to produce high quality coal and increase production.
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Jo Jun 13, 2023
Ha Chol Ho, a researcher at the Nano Physics Engineering Institute, has developed PVC-coated cloth and a PVC belt by nano technology.
Polyvinyl chloride (PVC) has been widely used in light industry, chemical industry, building materials industry, etc. because of its low price and good chemical stability.
However, PVC has a defect ― its weak mechanical strength.
The research team has succeeded in manufacturing PVC-coated cloth and a PVC belt by coating textile fabric with PVC paste before being treated with heat.
In order to raise their mechanical strength, they added nano SiO2 and nano CaCO3 to the PVC paste. Then, they chemically modified the surface of the nanoparticles with steric acid to improve the dispersivity of nano SiO2 and nano CaCO3 in the PVC paste.
Finally, they determined the optimal blending ratio by using Multiobject Genetic Algorithms and built its production process.
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Jo Jun 12, 2023
Folk song “Arirang”, representative of Korean folk songs and symbolic of the Korean nation, is a song of the Korean nation which is sung by each and every Korean and heard in any Korean settlements in the world.
A representative one among a great number of legends of the birth and etymology of a Korean folk song “Arirang” is “Songbu and Rirang”.
The legend goes like this.
Once upon a time a boy called Rirang and a girl called Songbu who were serving as servants for a landlord in a village took part in a riot raised by the local people in a year of crop failure and went into the depth of a mountain to avoid the pursuit of the government armed troops.
There, they got married and lived a happy life.
Later, Rirang decided to join the fight against exploiters and parted from his much beloved wife Songbu to set out on the journey over a series of mountain passes.
Songbu, gazing over the passes her husband crossed, sang a song of yearning, which was later handed down orally to finally become “Arirang”.
Sung by our people a lot, “Arirang” was diversified into a large number of local varieties ― “Sodo Arirang” of Phyongan Province, “Kangwondo Arirang” of Kangwon Province, “Tanchon Arirang” of Hamgyong Province, etc. to just name a few. All those have their features peculiar to their birthplaces.
“Arirang”, which is still widely sung by our people and known to the world, is a revised version as the theme song of a silent film “Arirang” by Ra Un Gyu in 1926.
The song is imbued with the spirit and sentiment of the Korean nation and it reflects simple aspiration of the Korean people for a happy life.
Today, “Arirang” is well-known as a famous song among people at home and abroad.
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Jo Jun 8, 2023
Pak Kwang Ok, a lecturer at the Faculty of Distance Education, has been giving importance to questions and answers in online lectures on “Insulant Production Engineering”, thus making remarkable achievements.
Her lectures are mainly based on two-way-exchange of knowledge between a teacher and students, not one-way transfer of knowledge from a teacher to students. In her lectures, students, as masters of learning, are able to think independently about problems and solutions to them, thus improving their independent faculties of learning, inquiry and presentation.
First, at the beginning of lectures, she associates new materials with what they have alrealy learnt in order to make it possible for them to draw the gist of a new lecture.
For example, in the lecture on synthesis of polyamide resin, she reminds them of the concept of a polyester resin so that students can easily understand what polyamide resin is.
Second, she raises problems for several occasions of teaching to make a question-and-answer session between a teacher and students, or students and students.
In the lecture on synthesis of polyester resin, for instance, she gives a practical discussion question “Which of the two methods of synthesis of PET resin is more advantageous and practical in terms of industrialization, directness or indirectness?” after explanation of production process of PET resin so as to make students have a discussion and present their discussion results.
In this course, students bring up their own questions that they found difficult to understand while working at factories, and find answers to them through discussions.
As mentioned above, she has been making her teaching more effective and raising her students’ practical abilities through question-and-answer sessions.
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Jo Jun 6, 2023
So Kyong Dok was a philosopher of materialism representative of the Korean medieval philosophy in the 16th century. His pseudonym was Hwadam or Pokjae.
He was born into a low-class aristocratic family in Kaesong in 1489. Although he was very clever from an early age, he could not start studying until he was 14 because of poverty.
Grown up in the historical environment from the late 15th century to the early 16th century when the contradictions of the feudal society started to be disclosed, he abandoned a government service from the start, out of discontent over a scramble for hegemony, arbitrariness and oppression of feudal ruling circles. Instead, he devoted himself to academic study and education of future generations, living in poverty all his life in Hwadam, Kaesong. That is why he was often called Teacher Hwadam.
Even though his philosophical idea represented the interests of low-class aristocrats, it exposed the misdeeds of the rulers of that time and expressed sympathy for the miserable life of peasants. Thus, it dealt a blow at the doctrines of Chu-tzu, which served as a basic idea of a ruling class, and exerted a great influence on the development of our country’s philosophy of materialism.
He died at the age of 57 in 1546. Reviewing his life, he said “I feel very happy with my perfect knowledge and satisfied with my worthwhile life.”
One of his books, which is still found, is “Hwadamjip” in four volumes.
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