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 HEATING APPLICATIONS IN WASTE REDUCTION AND ENVIRONMENTAL ENGINEERING

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

MICROWAVE APPLICATION TO CONTROL THE PROCESS OF CARBOTHERMAL REDUCTION OF METALS

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

Геофизические признаки источников гигантской наледи на р. Анмангында (Магаданская область)

Giant aufeis fields are the indicators of water exchange processes in the permafrost zone. The study of aufeis dynamics is relevant to assessing the state of the cryosphere in a changing climate. The Anmangynda aufeis which forms upstream of the Kolyma River basin, was as large as 6.8 km2 in the last century and is considered representative of the mountainous territories in the northeast Russia. In recent decades, there have been significant changes in the aufeis formation regime that require updating the understanding of the cryosphere processes. The historical observational data obtained in 1962-1990 for the Anmangynda aufeis allows using it as the present-day object of research.The main goal of geophysical research in 2021-2022 was to study the structure of the Anmangynda aufeis and aufeis glade to determine its genesis and development processes. The main tasks were to identify the boundary between frozen and unfrozen rocks, to reveal groundwater discharge channels, and to assess the aufeis thickness distribution. There were carried out georadar survey using an antenna unit with central frequency of 250 MHz and ground-based capacitively coupled electrical resistivity tomography. It was found that by April 5, 2021, the maximum ice thickness was 4.35 m with an average value of 1.35 m, and the volume of aufeis was 3.56 million m3. By means of georadar, there were performed identification and drilling verification of the groundwater discharge channels from alluvium to aufeis surface, located in the stream beds. There is geophysical evidence of deep bedrock groundwater sources. Based on the electrical resistivity tomography data, there were identified large and locally freezing river taliks, from which the water is squeezed onto the ice surface. It is recommended to conduct further interdisciplinary research to clarify the geophysical results obtained.Гигантские наледи являются индикаторами процессов водообмена в зоне распространения мерзлоты. Исследование динамики наледей является актуальной задачей оценки состояния криосферы в изменяющемся климате. Анмангындинская наледь, формирующаяся в верховьях бассейна р. Колымы, в прошлом веке достигала размеров 6.8 км2 и считается репрезентативной для горных территорий северо-востока России. В последние десятилетия произошли значительные изменения режима наледеобразования, требующие актуализации представлений о процессах криолитозоны. Наличие исторических данных наблюдений на Анмангындинской наледи позволяет использовать ее как объект исследований в настоящее время.Целью геофизических исследований 2021-2022 гг. являлось изучение строения Анмангындинской наледи и наледной поляны для уточнения ее генезиса и процессов формирования. Основными задачами были выявление границ мерзлых и талых пород, каналов разгрузки подземных вод и оценка распределения толщины наледного льда. Проведены георадиолокационные зондирования с антенным блоком центральной частоты 250 МГц и электротомография с заземлениями через емкостную связь. Установлено, что к 5 апреля 2021 г. максимальная толщина льда составила 4.35 м при среднем значении 1.35 м, объем наледи - 3.56 млн м3. С помощью георадара выявлены и заверены бурением каналы разгрузки подземных вод из аллювия под лед, расположенные в руслах проток. Выявлены геофизические признаки глубинных источников подземных вод в коренных породах. По данным электротомографии установлено наличие крупных и локальных промерзающих подрусловых таликов, из которых выжимается вода на поверхность льда

A myosin II nanomachine mimicking the striated muscle

The contraction of striated muscle (skeletal and cardiac muscle) is generated by ATP-dependent interactions between the molecular motor myosin II and the actin filament. The myosin motors are mechanically coupled along the thick filament in a geometry not achievable by single-molecule experiments. Here we show that a synthetic one-dimensional nanomachine, comprising fewer than ten myosin II dimers purified from rabbit psoas, performs isometric and isotonic contractions at 2 mM ATP, delivering a maximum power of 5 aW. The results are explained with a kinetic model fitted to the performance of mammalian skeletal muscle, showing that the condition for the motor coordination that maximises the efficiency in striated muscle is a minimum of 32 myosin heads sharing a common mechanical ground. The nanomachine offers a powerful tool for investigating muscle contractile-protein physiology, pathology and pharmacology without the potentially disturbing effects of the cytoskeletal-and regulatory-protein environment

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