SEARCH FOR RATIONAL EBGINEERING SOLUTIONS OF DIESEL LOCOMOTIVES FOR THE EASTERN RANGE

The purpose of the study is to search for rational engineering solutions for the main autonomous locomotive for the Eastern range of OAO Russian Railways. Research methods: methods of physical and field experiments, analytical methods for calculating the dynamics of the rolling stock. Research results and novelty: it is established that the use of a four-axle truck of a diesel locomotive TEM7 does not allow to create a locomotive that meets all the requirements of OAO Russian Railways, and the design of truck TEM7 is irrational for mainline locomotives; it is proved that the one-sided arrangement of brake blocks leads to deterioration in the locomotive braking properties. The bearing and axial towline, despite the use of an asynchronous engine, has an unsprung mass 1.5 times greater than that of the previously produced domestic analogue with a collector engine and almost the same mass of the wheel-motor unit; dynamic moments in the drive due to the lack of elastic elements during prolonged operation can reach 56% of the traction torque, which worsens the traction properties of the locomotive. Conclusion: it is advisable to carry out a design study of the drive variant with a support-frame asynchronous traction engine and an axial gearbox, as well as to conduct a technical and economic analysis and design study of a cheaper version of a diesel locomotive with sections on three two-axle bogies, maximally unified with electric locomotives, with a booster tanker module and AC-DC transmission with axial regulation of eight-pole collector motors with support-frame suspension.

Investigation on dust dispersion during support movement in a fully mechanized mining face and the technology with support frame enclosure dust control

A fully mechanized mining face is characterized by serious dust pollution and dust is a major cause of pneumoconiosis that haunts numerous miners. For a fully mechanized face having large mining heights, the main dust source in the pavement area is produced by the moving support frame. To reduce the amount of dust during support's movement, the distribution and dissipation of dust in this process were studied by combining numerical simulations with underground measurements. The results showed that with an increase of the distance from the air inlet, the wind speed of the sidewalk in the fully mechanized face first increased, then decreased, and finally increased again. At the position of the coal cutter, the highest wind speed was 1.78 m/s and the average wind speed of the roadway was about 0.8 m/s. The dust concentration at the dust source was >1000 mg/m3. An area with a high dust concentration and having a length of 15 m was formed on the rooftop, together with a 50 m long dust belt with a dust concentration of 300 to 450 mg/m3 in the pavement area of 10 m from the dust source. Beyond the 45 m radius from the dust source, the dust concentration was stable at about 250 mg/m3. Based on the dust production characteristics of the support frame, an enclosed dust-guiding device was designed and structure-optimized. Based on the on-site field application test results, it was found that the device has a satisfactory dust-guiding effect during support movement and the dust suppression rate near the dust source reached 94.8%.

THE MODELING OF CONSTRUCTIONS OF SHIPS LOADER’S ENGINE ROOM FOR THE IDENTIFYING THE CAUSE OF INCREASED VIBRATION

The article contains a finite element modeling of the stress-strain state of metal constructions of the foreign manufactured ships loader’s engine room, located in the seaport of Yuzhny’s town under the jibs lifting and lowering drive vibration source. The model have been developed taking into account the technical condition of the structure, which were determined after visual and instrumental examination. Have been researched the rotating structures of jibs lifting and lowering drive, means of ensuring smooth start and soft stop of the drive, have been increased the specific drive imperfections. Have been done the cinematic and dynamic calculations on a subject of definition of vibration parameters of rotation components of drive (electric motor, spur gear, gear, brace and rope drums). Have been offered the effective methods of experimental research, which including the scheme of installations of sensors at the structure of support frame of engine room, experimental measurements of vibration characteristics (vibration, amplitude, vibration velocity, vibration acceleration) and its mathematical processing. Have been done the comparison of the theoretical forced vibrations frequency of structural units of ships loader with experimentally determined data and localization of the most dangerous source of vibration. Have been revealed the main reason of excess vibration the structure of ships loader which are reduced rigidity of drive support frame which has been damaged from corrosion and consequently, resonance of rotational drive components with natural oscillations of ships loader structures. Have been developed the method of strengthening of structures of engine room, which have been damaged from corrosion during long term operation for the reduction of vibration intensity and for the further normal operation.

Preclinical study of a self-expanding pulmonary valve for the treatment of pulmonary valve disease

In the past decade, balloon-expandable percutaneous pulmonary valves have been developed and applied in clinical practice. However, all the existing products of pulmonary artery interventional valves in the market have a straight structure design, and they require a preset support frame and balloon expansion. This shape design of the valve limits the application range. In addition, the age of the population with pulmonary artery disease is generally low, and the existing products cannot meet the needs of anti-calcification properties and valve material durability. In this study, through optimization of the support frame and leaflet design, a self-expanding pulmonary valve product with a double bell-shaped frame was designed to improve the match of the valve and the implantation site. A loading and deployment study showed that the biomaterial of the valve was not damaged after being compressed. Pulsatile flow and fatigue in vitro tests showed that the fabricated pulmonary valve met the hydrodynamic requirements after 2 × 108 accelerated fatigue cycles. The safety and efficacy of the pulmonary valve product were demonstrated in studies of pulmonary valve implantation in 11 pigs. Angiography and echocardiography showed that the pulmonary valves were implanted in a good position, and they had normal closure and acceptable valvular regurgitation. The 180 days’ implantation results showed that the calcium content was 0.31–1.39 mg/g in the anti-calcification treatment group, which was significantly lower than that in the control valve without anti-calcification treatment (16.69 mg/g). Our new interventional pulmonary valve product was ready for clinical trials and product registration.