Исследование эффективности охлаждения вала печного вентилятора, оснащенного устройствами стержневого тип

The design of the air cooling device for the furnace fan’s shaft of rod type of three standard sizes is proposed. During the experiments at the experimental stand, the convective heat transfer from the surface of these devices to the environment at a different shaft rotation frequency was obtained critically. It was established that in the range of variation of the relative length of the rods from 3.3 to 6.1, a regime close to the self-similar mode takes place, where the heat transfer from their surface can be described by a universal dependence. In the range of variation of the relative length of the rods from 6.1 to 8.6, the experimental data are generalized in the form of a power law with a proportionality coefficient that depends on the ratio of the shaft diameter to the outer diameter of the device. The least coefficient of heat transfer from the external surface was found in ST-346 with the largest outside diameter and, correspondingly, the longest rods, which is apparently due to the fact that in the process of heat transfer from the shaft to the environment, the limiting heat exchange section is the heat supply by heat conduction along of the rods axis. The highest heat transfer coefficient under comparable conditions is observed in ST-286 with medium rods, where the heat supply is more balanced by thermal conductivity along the rods and its removal from their external surfaces by convection to the environment. When comparing the data obtained with CT-286 and CT-220, it was found that at the same shaft rotation frequency, the heat transfer coefficient over the surface of ST-286 is about 15–20 %, which is associated with a decrease in intensity of air blowing of shortened rods of ST-220 due to the decrease in their average linear speed of movement along the circumference. From the analysis of the obtained results, it follows that the most effective in comparable conditions is the device with a maximum diameter of 346 mm, where the dissipated thermal power in the steady state is 1.1 times higher than that of the device with a diameter of 286 mm and 2.0 times greater than for devices with a diameter of 220 mm. The obtained materials can be used in the design of heating and thermal furnaces using forced coolant circulation. © 2017 National University of Science and Technology MISIS. All rights reserved.The work was financially supported by Act 211 of the Government of the Russian Federation, contract no. 02.A03.21.0006

EXPERIMENTAL INVESTIGATION OF THE TRANSIENT CHARACTERISTICS AND MECHANICAL LOSSES IN Ni-Mn-Ga ALLOYS

The reported study was funded by RFBR, project number 20-32-90195

MICROWAVE APPLICATION TO CONTROL THE PROCESS OF CARBOTHERMAL REDUCTION OF METALS

The reported study was funded by RFBR, project number 21-58-53044

MICROWAVE HEATING APPLICATIONS IN WASTE REDUCTION AND ENVIRONMENTAL ENGINEERING

The reported study was funded by RFBR, project number 21-58-53044

Efficacy of polietilenglicole in bowel preparation for colorectal cancer surgery

Results of bowel preparation using polietilenglicole are demonstrated in the article. 254 colorectal cancer patients with no complications were enrolled. 242 (95.3 %) had good tolerability of bowel preparation. According to developed criteria 225 (88.6 %) had good bowel preparation on surgery, 23 (9.1 %) patients had satisfactory bowel preparation and 6 (2.4 %) had bad bowel preparation. 2 (0.8 %) patients had anastomotic leakage. Quality of bowel preparation was not associated with anastomotic leakage in this patient group

Development and study of devices for air cooling of the rotating shaft in high-temperature furnace fan of multi-disc type

The design of the device for air cooling of the shaft of a multi-disc furnace fan is developed. The dependences of convective heat transfer from the surface of this device to the environment of three standard sizes are obtained. It was established that the heat transfer during the motion of air in the inter-disc spaces of rotating cooling devices with different frequencies is similar to the heat transfer process in the case of its turbulent flow along the flat surface and is described in general by the power law dependence. The found values of the proportionality coefficients in this dependence take into account the design features of the studied devices and differ from the known values by 1.4 – 1.7 times. With the application of rules for thermal processes modeling, the obtained regularities can be used in the calculation of multi-disc cooling devices and for other designs of high-temperature furnace fans. The effect of changing the device external diameter on its cooling capacity was studied. It was established that a reduction in diameter from 313 to 250 mm leads to an increase in the uniformity of the distribution of air flow in the inter-disc space and contributes to an increase in the average heat transfer coefficient from a surface unit by 1.6 to 1.7 times in the comparable conditions. The possibility of increasing the uniformity of air blowing of the discs surface in devices with large diameters (MD-313 and MD-290) due to the increase in the dimensions of the inlet openings is limited according to the reduction in heat removal from the fan shaft due to the reduction in the cross-section area of blades material in the zone of cylindrical surface passing through their axes. The maximum heat flow from the fan shaft is provided by the device with a diameter of 290 mm, where two parameters are optimally combined: the value of the heat exchange surface and the intensity of its air blowing. Application of the developed devices allows the removed heat flow to be increased by 20 to 30 times compared to cooling of the surface of an open rotating shaft in a free environment in the comparable conditions. The presented materials can be used for the development of high-temperature fans for heating and thermal furnaces. © 2017, National University of Science and Technology MISIS. All rights reserved

Physical–Chemical Exfoliation of n-Alkylamine Derivatives of Layered Perovskite-like Oxide H2K0.5Bi2.5Ti4O13 into Nanosheets

In the present work, we report the results on exfoliation and coating formation of inorganic–organic hybrids based on the layered perovskite-like bismuth titanate H2K0.5Bi2.5Ti4O13·H2O that could be prepared by a simple ion exchange reaction from a Ruddlesden–Popper phase K2.5Bi2.5Ti4O13. The inorganic–organic hybrids were synthesized by intercalation reactions. Exfoliation into nanosheets was performed for the starting hydrated protonated titanate and for the derivatives intercalated by n-alkylamines to study the influence of preliminary intercalation on exfoliation efficiency. The selected precursors were exfoliated in aqueous solutions of tetrabutylammonium hydroxide using facile stirring and ultrasonication. The suspensions of nanosheets obtained were characterized using UV–vis spectrophotometry, dynamic light scattering, inductively coupled plasma spectroscopy, and gravimetry. Nanosheets were coated on preliminarily polyethyleneimine-covered Si substrates using a self-assembly procedure and studied using atomic force and scanning electron microscopy

Эффективность препарата полиэтиленгликоля при подготовке к операциям больных раком ободочной кишки

Results of bowel preparation using polietilenglicole are demonstrated in the article. 254 colorectal cancer patients with no complications were enrolled. 242 (95.3 %) had good tolerability of bowel preparation. According to developed criteria 225 (88.6 %) had good bowel preparation on surgery, 23 (9.1 %) patients had satisfactory bowel preparation and 6 (2.4 %) had bad bowel preparation. 2 (0.8 %) patients had anastomotic leakage. Quality of bowel preparation was not associated with anastomotic leakage in this patient group.В статье представлены данные о результатах подготовки кишечника к хирургическим вмешательствам препаратом полиэтиленгликоля (Фортранс®). Материал исследования составили 254 больных неосложненным раком ободочной кишки. Хорошая переносимость препарата отмечена у 242 (95,3 %) пациентов. В соответствии с разработанными критериями, подготовка кишечника при интраоперационной ревизии была расценена как хорошая у 225 (88,6 %) больных. В 23 (9,1 %) случаях подготовка кишки Фортрансом была признана удовлетворительной, а у 6 (2,4 %) – плохой. Несостоятельность межкишечного анастомоза была отмечена у 2 (0,8 %) пациентов. В данной группе больных влияние качества подготовки кишечника на частоту несостоятельности анастомозов не прослеживается