The process of sizing fine particulate material particles with different particle sizes is largely divided into sieving and sorting processes. Currently, a circular vibrating screen is used worldwide to reduce power consumption and improve classification efficiency of fine particles.

Circular vibrating screens are widely used in mining, building materials, chemical and pharmaceutical industries in the world today due to their advantages such as simple structure, small installation area, high reliability in operation and relatively high screening efficiency as compared to dry ultra-fine processing equipment.

The sieving and grading process of powder particles widely used in various sectors of the national economy also uses circular vibrating screens, air classifiers, spiral classifiers, water cyclones, etc. Although a circular vibrating screen has been used for the screening of particulate materials, it has a low throughput and does not use a multi-stage screen.

Ri Chol, a researcher at the Faculty of Mining Engineering, proposed a structural scheme of a circular vibrating screen with a two-stage screen surface for particle size separation of perlite powder particles in the process of crushing and grinding of perlite ore for the production of expanded perlite for soilless vegetable cultivation substrate, and optimized design parameters by simulating sieving operations using EDEM based on the kinetic analysis of screen surface.

The results showed that the screening efficiency was 98.87% when the eccentric mass was set to be 1kg and the phase angle between eccentric mass 45°.

October is a rich period when the weather gets cool, mountains and fields put on beautiful autumnal tints and plump ears of crops ripen in paddy and dry fields.

The seasonal subdivisions in October are Hallo and Sanggang.

Hallo means the time when cold dew begins to fall and it falls on October 8 this year.

Sanggang means the coming of frost and it falls on October 23 this year.

After Sanggang, the weather gets cold and the temperature difference between day and night gets bigger.

October is a busy season with harvesting and threshing of grain.

The Korean people have eaten various dishes that suit the seasonal characteristics of the October seasonal subdivisions.

Typical of them are soybean dishes and loach soup.

They also played different kinds of folk games.

Especially, children’s favourite games of hide-and-seek, hopscotch and tail-taking were spectacular.

Thus, the Korean people have created and carried on diligent and diverse working life and customs of diet, dressing and folk games suited to the seasonal characteristics of the period of Hallo and Sanggang from olden times.

Magnetotellurics (MT) is widely used for oil exploration. In MT, the time series of two telluric and three magnetic components of the magnetotelluric field are generally recorded at the ground surface in the Cartesian coordinate system. In practice, however, there are some difficult cases for setting two telluric lines orthogonally to record telluric components due to obstacles like roads, wetlands, rivers, cliffs, rice banks, buildings, etc. at a given MT site.

Kim Ji Yang, a researcher at the Faculty of Earth Science and Technology, proposed a method of converting telluric components recorded in non-orthogonal coordinate systems to those in orthogonal coordinate systems by means of mathematical coordinate transformation and verified its possibility and applicability through model and field tests.

This method makes it more convenient for MT field crews to choose site positions and set electric lines.

For more information, you can refer to his paper “Dealing with Non-orthogonally Measured Telluric Components in Magnetotellurics” in “Journal of Mathematical Methods in Engineering” (SCI).