In recent years, the Budryk Coal Mine (KWK Budryk) reached the mining depth of 1300 m, where there is about 160 million tons of coal, including 120 million tons of coking coal (type 35). The task of the Coal Processing Plant complex modernization was undertaken. The article presents the modernization of coal screening, classification and dewatering systems at the KWK Budryk Processing Plant and the implementation of screening of PROGRESS ECO sp. z o.o. SK. The modernization project defined the following technical requirements for all screens in the KWK Budryk Coal Processing Plant extension project:

- Vibrating screens with a linear type drive with a drive unit placed on the drive beam of the trommel screen in the form of vibration generators;

- Screen drives equipped with a starting-braking device;

- The use of main screen drive bearings with a nominal service life of at least 40,000 man-hours;

- All work surfaces made of materials with a strength of up to 80 mm grain and abrasion resistance; side strips and sieves fixed in a way ensuring trouble-free operation, and at the same time quick and easy replacement;

- Sheets made of stainless steel;

- Side walls, beams and other elements attached to them connected with screws using a system protecting against corrosion and elements separation;

- The use of a work parameters monitoring and visualization system, i.e.

- pitch of the riddle,

- bearing operating temperatures and the condition of their wear.

Three types of screens were provided:

- PWP1-1Z-2,8x6,0 screeners that alternatively perform sieving or desliming processes,

- PWP1-2.4x6.0 screening machines performing desliming processes,

- PWP1-2.0x6.0 screens performing the classification process.

In this paper, we proposed a novel design of U-slotted SIW antenna. Our antenna design is aimed to cover upper K-band and lower Ka-band spectrums, specifically from 24 GHz to 32 GHz. It has a compact square size of 5.2 x 5.2 mm2. We use a rectangular truncated corner to optimize the square radiator. The optimized rectangular truncated corner size of 2 x 0.8 mm2 gives an impedance bandwidth of 7.87 GHz. SIW cavity is constructed by using multiple metallic via-holes which are drilled in a dielectric substrate establishing. Next optimization, applying the U-shaped slot and SIW structure yield a wider impedance bandwidth of 8.89 GHz, there is about 1.02 GHz of impedance bandwidth enhancement. In addition, the SIW structure gives a higher gain of 7.63 dB and decreases the sidelobe level of -12.1 dB. Implementation of the SIW structure significantly decreases the size of antenna while keeping the antenna parameter’s performances.

An optimal design of a slot waveguide is presented for realizing an ultrafast optical modulator based on a 220 nm silicon wafer technology. The recipe is to maximize the confinement and interaction between optical power supported by the waveguide and electric field applied through metallic electrodes. As height of waveguide is fixed at 220 nm, the waveguide and slot width are optimized to maximize the confinement factor of optical power. Moreover, metal electrodes tend to make the waveguide lossy, their optimal placement is calculated to reduce the optical loss and enhance the voltage per unit width in the slot. Performance of an optimally designed slot waveguide with metal electrodes as ultrafast modulator is also discussed.

The mine seals in coal mines with a good impact resistance and air tightness are mainly used to isolate abandoned mining areas from active workings. For one thing, it can prevent the leakage of harmful gases, such as toxic gas from abandoned areas. For another, once an underground mine explosion happens, it can effectively block the spread of the explosion between the abandoned mining areas and the active workings. Hence, it is of great significance to study the explosion-proof performance and mechanical properties of the mine seals. First of all, the effect of slotting on the stability of the seals in coal mines under explosion load was explored in this study. By numerical simulations, the mechanical response characteristics of the seals with or without cutting a slot under the explosion load were compared in detail. The results show that slotting improved the stress concentration at the contact surface of surrounding rock by transferring partial impact received by mine seals to the surrounding rocks, thus, to achieve the effect of buffering explosion impact. Besides, such effect will be enhanced with increasing cutting depth into rock, and will stabilize when the depth is 20 cm. On this basis, the mechanical properties and damage of the seals constructed by different materials (standard brick and #C40 concrete) under the explosion load were compared. It was found that once a slot was set, the maximum deformation of the concrete seal was reduced, while the maximum deformation of the brick seal increased. Since the non-deformability of the concrete seal is obviously stronger than that of the brick seal, with the impact resistance stronger than that of the brick seal, the concrete seal is more suitable for slotting. Moreover, the damage of the seals in underground coal mines under the strata ground pressure was studied; the results of which show that the damage state under the ground pressure can be divided into 3 levels, i.e. no damage, minor damage and rapid development of damage. Meanwhile, it was found that the prestressed structure formed by the ground pressure at the level of no damage can enhance the protective effect of the seals in coal mines. However, when the ground pressure was further developed, the seal itself was destroyed and the protective effect was lost. In addition, the influence of roof to floor moving convergence, a deformation parameter of the roadway, on the seals was also investigated. The results show that the ground pressure and roof-to-floor convergence act on the seals in coal mines in the same way, thus roof to floor moving convergence can replace the ground pressure to analyze other related mechanical properties of the seals in coal mines in the future researches.