Article examines the key aspects of implementing an urban air mobility system in the Republic of Belarus. Mathematical modeling is used to assess the probabilities of UAV-to-UAV collision threats during circular air traffic management. Requirements are developed for the further development of a dynamic UAV distribution model for urban air mobility.
Modern unmanned air vehicles (UAV) are equipped with satellite navigation receivers to provide stability in space and maintain the desired track. The satellite navigation receivers feature low noise immunity that can result in loss of satellite signals and, hence, in deviation from the desired track or control loss. The paper presents a technique for improving the immunity of a satellite navigation receiver under wide- and narrow-band interference as well as deceptive interference. The technique was implemented through the analysis of NMEA output data of a satellite navigation receiver. The main advantage of the proposed technique is the use of relatively small computational power of the onboard computer. The proposed technique is based on the analysis of the signal/noise ratio, the number of navigation satellites used as well as the integrity of the output coordinates of an UAV receiver. The proposed technique allowed developing an algorithm for detecting the interference which consists of two stages. At the first stage, presence of interference is identified, the second stage implies the comparison of the output coordinates of the receiver with the desired ones making it possible to assess the effects of deceptive interference. The algorithm is implemented in the G programming language in the LabVIEW environment. The technique and the algorithm for identifying the interference were tested by conducting a series of semi-natural experiments with the CH-3803M signal simulator which allowed estimating the threshold values of signal levels from navigation satellites in the presence of interference. As a test sample the ATGM336H multisystem satellite navigation receiver was used that provides a possibility to select a satellite navigation system (GLONASS, GPS or BeiDou) or to use their combination for solving an UAV navigation problem. The authors conducted a series of experiments for assessing the effects of different interference on the performance of the ATGM336H satellite navigation receiver.
Experimental equipment for producing charcoal from sawmill residues using thermochemical conversion of biomass in an oxygen-free environment has been developed. This equipment features thermal conversion of wood raw materials in a pyrolysis chamber equipped with microwave sources. The pyrolysis equipment includes a unit for producing generator gas from organic waste, a wood pyrolysis unit, a pyrolysis chamber purging system with inert gas, an afterburner for the generator gas and pyrolysis gas mixture, a combustion product temperature control unit, a heat exchanger, a smoke exhauster, a pyrolysis unit control and monitoring system, and a chimney. Magnetrons were used as microwave sources. A description of the testing methodology for the equipment for producing charcoal in the presence and absence of a microwave field is provided. Hardwood (split maple firewood) was used in the tests. The results of the study indicate that the use of microwave technology can increase the rate of thermochemical destruction of wood, increase the productivity of equipment for the production of charcoal, and also obtain a higher yield of charcoal per unit mass of the original wood, raw material or product with a higher calorific value and lower ash content.For example, the productivity of the experimental pyrolysis unit without microwaves was 1.42 kg/h, while with microwaves, it was 1.73 kg/h, an increase of 22 %. The developed technology for producing charcoal by thermal pyrolysis in the presence of microwaves offers economic and energy-efficient potential.
The paper presents the results of a kinetic study of the thermal decomposition of calcium carbonate under conditions of continuous heating to a temperature of 1273 K at a constant rate of 1.25, 2.5, 5, 10, and 20 K/min. The integral method and the Coats–Redfern method were used to describe the reaction mechanism and determine the macrokinetic parameters. Experimental dependences of the logarithm of the preexponential factor on the activation energy were obtained. The dependences of the activation energy and preexponential factor on the heating rate are shown. The effect of the heating rate of calcium carbonate on the activation energy can be explained by the relationship between the heating rate and the concentration of CO2. Equations are proposed for calculating the reaction rate constant using the integral data processing method and the Coats–Redfern method. It has been demonstrated that the integral method and the Coats–Redfern method allow one to calculate the macrokinetic parameters of the thermal decomposition of calcite with comparable accuracy and taking into account the heating rate in these calculations makes it possible to obtain calculated values of the degree of conversion, the standard deviation of which from the experimental data is <4.1
