Emission Monitoring Mobile Experiment (EMME): An overview and first results of the St. Petersburg megacity campaign 2019

Global climate change is one of the most important scientific, societal and economic contemporary challenges. Fundamental understanding of the major processes driving climate change is the key problem which is to be solved not only on a global but also on a regional scale. The accuracy of regional climate modelling depends on a number of factors. One of these factors is the adequate and comprehensive information on the anthropogenic impact which is highest in industrial regions and areas with dense population – modern megacities. Megacities are not only “heat islands”, but also significant sources of emissions of various substances into the atmosphere, including greenhouse and reactive gases. In 2019, the mobile experiment EMME (Emission Monitoring Mobile Experiment) was conducted within the St. Petersburg agglomeration (Russia) aiming to estimate the emission intensity of greenhouse (CO$_{2}$, CH$_{4}$) nd reactive (CO, NO$_{x}$) gases for St. Petersburg, which is the largest northern megacity. St. Petersburg State University (Russia), Karlsruhe Institute of Technology (Germany) and the University of Bremen (Germany) jointly ran this experiment. The core instruments of the campaign were two portable Bruker EM27/SUN Fourier transform infrared (FTIR) spectrometers which were used for ground-based remote sensing measurements of the total column amount of CO$_{2}$, CH$_{4}$ and CO at upwind and downwind locations on opposite sides of the city. The NO$_{2}$ tropospheric column amount was observed along a circular highway around the city by continuous mobile measurements of scattered solar visible radiation with an OceanOptics HR4000 spectrometer using the differential optical absorption spectroscopy (DOAS) technique. Simultaneously, air samples were collected in air bags for subsequent laboratory analysis. The air samples were taken at the locations of FTIR observations at the ground level and also at altitudes of about 100 m when air bags were lifted by a kite (in case of suitable landscape and favourable wind conditions). The entire campaign consisted of 11 mostly cloudless days of measurements in March–April 2019. Planning of measurements for each day included the determination of optimal location for FTIR spectrometers based on weather forecasts, combined with the numerical modelling of the pollution transport in the megacity area. The real-time corrections of the FTIR operation sites were performed depending on the actual evolution of the megacity NO$_{x}$ plume as detected by the mobile DOAS observations. The estimates of the St. Petersburg emission intensities for the considered greenhouse and reactive gases were obtained by coupling a box model and the results of the EMME observational campaign using the mass balance approach. The CO$_{2}$ emission flux for St. Petersburg as an area source was estimated to be 89 ± 28 ktkm$^{-2}$ yr $^{-2}$ , which is 2 times higher than the corresponding value in the EDGAR database. The experiment revealed the CH$_{4}$ emission flux of 135 ± 68 tkm $^{-2}$ yr $^{-1}$, which is about 1 order of magnitude greater than the value reported by the official inventories of St. Petersburg emissions (∼ 25 tkm$^{-2}$ yr $^{-1}$ or 2017). At the same time, for the urban territory of St. Petersburg, both the EMME experiment and the official inventories for 2017 give similar results for the CO anthropogenic flux (251 ± 104 tkm $^{-2}$ yr $^{-1}$ s. 410 tkm $^{-2}$ yr $^{-1}$) nd for the NO$_{x}$ anthropogenic flux (66 ± 28 tkm$^{-2}$ yr $^{-1}$ vs. 69 tkm $^{-2}$ yr $^{-1}$)

Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015

Studying the Influence of Structural-mode Parameters on Energy Efficiency of the Plough PLN-3-35

Current research addresses improving the effectiveness of the technological process of tilling the soil for agricultural crops. Based on the experimental study into the technological process of plowing, we have determined the efforts that act on the mechanism of a tractor's attachment and a landside. It was found that universal casings for ploughs enhance plowing effectiveness by improving their stability. It was established that this leads to a decrease in the energy intensity of a plough casing during soil tilling, as well as provides for a uniform wear of the friction surface due to changes of its surface. It was determined that it is necessary to improve the components of tillage machinery in order to prolong the mean time between failures for working bodies and to reduce their traction resistance. It was established that the influence of a transverse pressure force that acts on a plough's landsides has not been sufficiently studied. Not enough attention has been paid to determining the magnitude of a traction effort for each link in the mechanism of an attachment to a tractor's assembly. One of the reserves for enhancing technological indicators and reducing energy intensity of a plowing assembly is the structural improvement of a standard plough's landside. In the course of experimental study, we used a system for measuring the dynamics and energy efficiency of mobile machines, which refers to the tools for technical diagnosing and operational control. The strain gauges were placed on a plough's landside, at the middle, left, and right links in the mechanism of a tractor's attachment. It was determined that the mean value for a shear force of pressure acting on a landside installed at the bearer of a first plough's casing is 1,610–1,668 N. At the bearer of a second casing, it is 1,525–1,630; at the bearer of a third casing, it is 1,848–1,870 N. It has been proposed to use, instead of a standard landside for the mounted ploughshare PLN-3-35, a flat-rounded element in the form of a disk with a hub that has a horizontal axis of rotation. The disk transforms the sliding friction forces into rolling friction forces. The application of disk reduces energy intensity of the plough by 13–15 %. That leads to a decrease in the traction effort of the plough's casings, improves their stability, and lowers consumption of petrol, oil, and lubricants