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The article contains the authors’ research in the field of jet propulsion systems with low energy consumption of small spacecraft of the class of nanosatellites. The paper presents a microwave ion engine with double acceleration of ionized gas in the gaps formed by the end surfaces of cylindrical resonators. The results of an experimental study of the pressure force of a jet set of ionized gas by the aerodynamic double angle method are presented. A stand for determining the power parameters of week plasmajet is presented. The design of the prototype is presented. The total energy consumption of the prototype is 5 watts, the accelerated gas flow rate is up to 200 km/s, the jet pressure force on the sensing element of the stand is 0,1 μN. The working body of the prototype is nitrogen at a pressure in a vacuum chamber of 18 Pa.

The authors continue their work in the field of calorimetric studies of the parameters of an accelerated ionized gas jet of prototypes of microwave ion micro-thrusters with an energy consumption of up to 10 watts. This paper presents an improved calorimetric method. The introduction into the design of a heat receiver in the form of a thin screen makes it possible to allocate the thermal component formed by the passage of an electric current through the plasma in the accelerating gap. Calorimetric studies of the prototype with a two-electrode accelerating system are carried out at the same accelerating voltages and power of the microwave generator and different mass gas flow rates. It is shown that at a nitrogen consumption of 5,668•10–9 kg/s, the velocity of the mixed jet (neutral gas with ionized component) of the gas was 63,75 m/s, the jet thrust is 0,36 μN. With a nitrogen consumption of 1,611•10–8 kg/s, the speed of the mixed gas jet was 47,9 m/s, the jet thrust was 0,77 μN.

The lead-free ferroelectric 0.4Ba _0.85 Ca _0.15 Zr _0.10 Ti _0.90 O _3 –0.6BaTi _0.89 Sn _0.11 O _3 (0.4BCZT–0.6BTSn) ceramics were successfully prepared by the sol–gel process. Raman spectroscopy was used to examine the structural properties of the 0.4BCZT-0.6BTSn sample. The findings indicate that the sample was well crystallized into a single perovskite structure. The phase transitions of the studied sample have been investigated using the DSC technique. The electrocaloric effect (ECE) properties were indirectly determined using the Maxwell approach. Under a relatively low applied electric field of 30 kV cm ^−1 , the results show enhanced electrocaloric temperature change and entropy change of ΔT = 1.32 K and ΔS = 1.41 J/kg.K, respectively. Besides, the electrocaloric responsivity ( ξ _max = 0.45 K·mm/kV) obtained is among the highest reported values in pb-free ferroelectrics near room temperature. These findings demonstrate that the lead-free 0.4BCZT–0.6BTSn ceramic is a promising candidate for solid-state cooling applications.

Nowadays, Moroccan oasis agro-ecosystems are under intense effect of natural and anthropogenic factors. Therefore, this essay proposes to use Leaf Area Index (LAI) to assess the consequences of the oases long-term biodegradation. The index was used as a widely-applied parameter of vegetation structure and an important indicator of plant growth and health. Therefore, a new optical multispectral Sentinel-2 data were used to build a long term LAI time series for the area of the Erfoud and Rissani oases, Errachidia province in Drâa-Tafilalet region in Morocco. Nine images of LAI spatial distribution over the study area were obtained by means of SNAP Biophysical Processor over the period since July 2015 till May 2018. Time series analysis of the resultedmaps has revealed a stable trend towards the average LAI decreasing and vegetation structure simplification as a consequence.