Case study of ozone anomalies over northern Russia in the 2015/2016 winter: measurements and numerical modelling

Episodes of extremely low ozone columns were observed over the territory of Russia in the Arctic winter of 2015/2016 and the beginning of spring 2016. We compare total ozone columns (TOCs) from different remote sensing techniques (satellite and ground-based observations) with results of numerical modelling over the territory of the Urals and Siberia for this period. We demonstrate that the provided monitoring systems (including the new Russian Infrared Fourier Spectrometer IKFS-2) and modern three-dimensional atmospheric models can capture the observed TOC anomalies. However, the results of observations and modelling show differences of up to 20&thinsp;%–30&thinsp;% in TOC measurements. Analysis of the role of chemical and dynamical processes demonstrates that the observed short-term TOC variability is not a result of local photochemical loss initiated by heterogeneous halogen activation on particles of polar stratospheric clouds that formed under low temperatures in the mid-winter.</p

High-Speed Monitoring of Dust Particles in ITER ELMs Simulation Experiments with QSPA Kh-50

Dust generation under powerful plasma stream impacts has been studied in ITER ELM simulation experiments with QSPA Kh-50 plasma accelerator. Repetitive plasma exposures of tungsten have been performed by 0.25 ms plasma pulses and the heat load varied in the range (0.1÷1.1) MJm-2. Main characteristics of dust particles such as a number of ejected particles, their velocity, angular distribution and start time from the surface are investigated. Dust particles have not been observed under heat load below the cracking threshold. Quantity of dust particles rises with increasing heat load. Average velocities of dust particles are found to be strongly dependent on their start time from the surface after beginning of plasma-surface interaction. Maximal velocity achieved a few tens of meters per second

Local Magnetohydrodynamic Characteristics of the Plasma Stream generated by MPC

This paper investigates the spatial distributions of electrical current which flows inside the plasma stream generated by a magnetoplasma compressor (MPC). Two different modes of MPC operation with different gas supply scenarios have been applied in the experiments presented here. The first is the operation mode with a pulse injection of xenon into the interelectrode space, and the second is the operation mode with residual helium in the chamber and local injection of xenon directly into the compression zone. The maximum value of the electric current observed outside the MPC channel is 15 ÷ 20% of the total discharge current. Electric current vortices were discovered in the plasma stream. The amplitude of the current in the vortices reaches 50% of the total discharge current. The maximum EUV radiation power was measured in the mode of MPC operation with local xenon injection. Power in the wave range 12.2 ÷ 15.8 nm achieves up to 16 ÷ 18 kW

Local Magnetohydrodynamic Characteristics of the Plasma Stream generated by MPC

This paper investigates the spatial distributions of electrical current which flows inside the plasma stream generated by a magnetoplasma compressor (MPC). Two different modes of MPC operation with different gas supply scenarios have been applied in the experiments presented here. The first is the operation mode with a pulse injection of xenon into the interelectrode space, and the second is the operation mode with residual helium in the chamber and local injection of xenon directly into the compression zone. The maximum value of the electric current observed outside the MPC channel is 15 ÷ 20% of the total discharge current. Electric current vortices were discovered in the plasma stream. The amplitude of the current in the vortices reaches 50% of the total discharge current. The maximum EUV radiation power was measured in the mode of MPC operation with local xenon injection. Power in the wave range 12.2 ÷ 15.8 nm achieves up to 16 ÷ 18 kW

Stabilization of shapes and dimensions of compressed wood using chemical and physical methods

Descriptions of methods and results of experiments on the preservation of geometry and dimensional parameters of compressed wood using chemical and physical methods are given. Wide ranges of substances were used as chemical stabilizers in urea aqueous solution (plasticizer during pressing). Wood treatment with ultrasound, liquid nitrogen and pulsed magnetic field was used as physical methods. Urotropine, urea-formaldehyde oligomer, phenol-formaldehyde resin, butyric anhydride and physical methods (liquid nitrogen and pulsed magnetic field), as well as ultrasound can be applied to increase form stability of pressed wood to the level of swelling in water and water absorption of natural wood (respectively, 15-20% and 30-45%). Cashew nut shell liquid is recommended to obtain stable pressed wood. The liquid, with a content of 6-12% (by dry residue) relative to the mass of dry wood during heat treatment in the temperature range of 150-155°C for 8 hours, gives limiting volume swelling 7-8% and limiting water absorption 14-18%. Fully stable compressed wood was obtained after exhaustive acetylation with acetic anhydride and subsequent maximum impregnation with phenol alcohols (more than 70% of content) and thermocatalytic curing. However, this method cannot be recommended due to high toxicity and material weakness

Decomposition Dynamics of the Wrack of Different Origin in the Black Sea Sandy Littoral

The role of sand interstitial community in process of decomposition of different origin wrack (seaweed, seagrass and mussel) are considered in with the results of laboratory experiments. Quantitative changes of organic matter content, bacteria, marine fungi, microalgae, flagellates, ciliates and insects in wrack and underlying sand are studied. The results obtained in the laboratory closed to the natural condition