Calculation of temperature waves in kurums

The article indicates the relevance of the study of heat transfer processes in kurums. Boundary value problems of vertical temperature change in kurums and in the underlying rock base are solved, when the temperature on the surface of kurums changes according to a given periodic law, which simulates daily and seasonal temperature fluctuations. The cases when the rock base is a heat-conducting medium and permafrost are considered. Some regularities of temperature propagation along the depth are revealed.

The «D.I. Mendeleev’s Periodic System of the Elements» Mural Near the Mendeleev Institute for Metrology in Saint Petersburg: How Metrologists Celebrated the 100th Anniversary of the Scientist

This article is timed to the celebration of the International Year of the Periodic Table of Chemical Elements, declared by the UN and UNESCO in connection with the 150th anniversary of the discovery by D. I. Mendeleev of the Periodic Law of Chemical Elements (1869). The article highlights the metrological activity of D. I. Mendeleev and tells about how in the scientific metrological center, he created the Main Chamber of Weights and Measures. Now the D.I. Mendeleyev Institute for Metrology (VNIIM) preserves the memory of the life and activities of the great Russian scientist and encyclopedist. Based on the research carried out in the archives of St. Petersburg and the funds of Metrological Museum, the article for the first time details the history of the formation of the Mendeleev memorial complex on the territory of VNIIM. The contribution of the institute metrologists to the creation of such famous sights of St. Petersburg as the monument to D. I. Mendeleev (sculptor I. Ya. Ginzburg, 1932) and the mural (mosaic) «D. I. Mendeleev Periodic system of elements» (1935) on the occasion of the 100th anniversary of the scientist is shown. All peripteries, related to the installation of the monument - table are described: a selection of options for the arrangement of elements, decoration, manufacturer and manufacturing techniques, coordination with various organizations, solving financing issues.

Seasonal temperature waves in the ground, nonperiodic case

Seasonal fluctuations in soil temperature at a depth of several meters are considered. It is assumed that the temperature of the earth surface changes strictly periodically. Then, according to the Fourier law, the soil temperature at depth will also change periodically with a smaller amplitude and time lag. What happens if we let the temperature on the surface deviate from the strict periodicity at some point in time? How will the nature of soil temperature fluctuations change at depth? Two types of deviations of the surface temperature from the periodic law are considered: 1) A sharp cold snap. For 30 days, the temperature of the earth surface is -30оC and 2) Warm winter. It is assumed that the temperature of the earth surface is zero during the winter months. Graphs of temperature changes at different depths in both cases are plotted. Conclusions are drawn about the duration of the period of noticeable deviations and the magnitude of the temperature deviation from the normal value.

FORMATION OF PACKINGS WITH THE HELP OF WINDING MACHINE WITH PERIODICAL SPEED BUMP OF THE WINDING-UP ROLLER

For the formation of a high-quality package of cross winding on machines equipped with winding mechanisms with a frictional drive of the package, it is necessary to include special devices in their composition that provide a change in the speed of the yarn feeder or bobbin according to a periodic law with a cycle duration of at least six periods of the yarn feeder movement. Changing the speed of the bobbin can be provided by slipping it by a controlled amount. The amount of slip is determined by the appropriate selection of the winding shaft acceleration (deceleration) and the pressing force of the bobbin against the winding shaft. A mathematical model has been obtained that describes the change in the difference between the displacements of points on the surface of the bobbin and the winding shaft when the winding shaft is accelerated. It is shown that in this way it is possible to effectively eliminate defects in the winding structure in the form of bundles and ribbons.

ПОЧВОВЕДЕНИЕ – НАУКА ХИМИЧЕСКАЯ

The exhibition "Soil Science is a Chemical Science" is dedicated to the 150th anniversary of the discovery of the periodic law of chemical elements by D.I. Mendeleev. It is intended to popularize knowledge about soil and to draw the attention of schoolchildren, students and young people to the problems of conservation of soil as the most important natural resource. Upon attending the exhibition, its visitors become aware, in a systematic way, of novel aspects of the composition, structure, and properties of the soil and its role in the functioning of the biosphere and in human life. The exhibition draws attention to the global problems of our time, including food safety and the environmental safety of soils.