Moscow State Forest University

The paper analyzes the thermal stability and mechanical properties of wood-polymer composites based on polyethylene at different temperatures. The obtained data indicate the need to take into account the thermomechanical parameters of WPC in the development and improvement of molding technologies for products made of these materials.

We present a hybrid ML framework combining regression and classification for QoT prediction in coherent optical networks. Trained on realistic data, it enables accurate estimation and detection of inoperability causes across diverse topologies and configurations.

Forest fires are accompanied by the release of a huge amount of heat, and the temperature at the edge of a forest fire, where firefighting equipment usually operates, reaches 300-700 °C. Fire engines are exposed to intense heat to extinguish forest fires. The main requirement for the design of such machines is the availability of rational thermal protection. Studies of various methods of thermal protection of cabins have showed the possibility of lowering the temperature on the inner surface of the cabin, but these methods show low efficiency. Protection of cabs from thermal radiation is not provided in the new developments of forest fire machines. It is proposed to use pre-preg coatings to protect cabins of forest fire engines. They are successfully used in spacecraft designs. Recent technologies for the production of such materials, developed recently, have significantly reduced the cost of production of these materials. It expands the possibilities of their application for other equipment subjected to intense heat exposure. The calculations have showed that the heat-protective coatings of the cabins made of pre-pregs quickly warm up to acceptable temperatures. However the use of water reserves in the tank of the car to cool the inside of the cabs provides high protection efficiency even at the limiting values of heat fluxes that occur in the fireplace. At the same time, water is not consumed; it is heated, circulating between the tank and the heat exchanger. The proposed method of protecting cabs of fire machines from thermal radiation is original one. It is a subject of further development.

Upon carrying out logging, residues remain in the cutting area. Logging residues are an additional source of wood raw material for the production of fuel chips to be used in bioenergetics. In order to plan the logging residues collection and processing technology, it is necessary to gather information on the amount of this type of waste and its distribution within the cutting area.The article deals with the line intersect (LIS) method.The aim of this article was to assess the accuracy of the LIS method for quantifying logging residues after cut-to-length logging (CTL), uniformly distributed within the technology traffic lanes (strips) of width b on the cutting area of arbitrary shape S.The studies were conducted using computer simulations. In the models, logging residues are represented as clusters in the form of circles. The laws of distribution of the radius of the clusters and their position in the plot were determined by field measurements.In the simulations, clusters uniformly distributed along the X-axis and stripes on the Y-axis were considered. The samples of lines were the set of lines of different length and mutually perpendicular and parallel to the coordinate axes X, Y.In the simulations, four types of stripes were considered with a different angle to the Y-axis. Type 1 – angle = 0°, type 2 – angle = 15°, type 3 angle = 30°, type 4 – angle = 45°.It was determined through simulation that the estimated mean radius of the clusters is greater by 24% than the true mean radius.The LIS method formula is appropriate for estimating the amount of forest residues after CTL logging provided the true mean radius is taken. According to the results of simulation experiments, it was found that the results are in good agreement with the theoretical formulas if the location of the sample lines is mutually perpendicular and parallel to the coordinate axes X, Y of the area. Differences remain within the limits of 20% error.

Primordial stellar-mass black holes, which may contribute to dark matter and to the observed LIGO binary black hole coalescences, are expected to be born with very low spins. Here we show that accretion mass gain by the components of a primordial black hole binary from the surrounding matter could lead to noticeable spins of the components prior to the coalescence provided high initial orbital eccentricities.

We analyzed the diversity of vascular plant species growing on microsites formed after tree falls with uprooting as a result of catastrophic windthrow that occurred in the temperate broadleaved forests of the Kaluzhskie Zaseki Reserve in 2006. Size characteristics of pits and mounds formed by uprooting of 110 individuals of 9 tree species were measured. Vegetation on microsites formed by 45 fallen trees of 8 species was described. We distinguished the following microsites: 1) top of the mound; 2) back side of the mound; 3) front side of the mound (from the trunk side); 4) pit over the mound; 5) pit in front of the mound in the case of rotational treefalls; 6) part of the trunk close to the roots (deadwood). Vegetation on 45 plots of 1x1 m in size and located close to but not affected by tree uprooting (reference plots, or reference communities) was also described. The results of the indirect ordination analysis revealed that the ecological and phytocoenotic differences between the plant associations of Querco -Tilietum cordatae and Aceri campestris -Tilietum cordatae persisted in the areas of catastrophic windthrow both on the plots of reference communities and in vegetation overgrowing pits and mounds. Ordination showed differences between the vegetation in the microsites formed by tree uprooting in a series of mound -deadwood -pit -reference community. On 251 plots, 78 vascular plant species were totally registered, among them 26 species were not found in the reference plots but occurred in the pit-and-mound microsites; 6 species were not found before the windthrow study in the descriptions of broadleaved and aspen forests of the Reserve, and 8 species were found in the descriptions of those forests no more than three times. New species are mostly species from the boreal (Phegopteris connectilis, Sambucus racemosa), nitrophilous (Rubus

Torrefication is a process of low-temperature pyrolysis of wood, used to improve the properties of wood fuel. Torrefied fuel has several advantages compared to the original. Thermal degradation causes changes in mass and composition of wood with increase in carbon percentage, which leads to an increase of combustion value Q. Thermal destruction can be viewed as a multistage process. The degree of decomposition of the material depends on temperature, time of exposure to heat and kinetic parameters of each stage of the process. The article presents the results of experimental studies of combustion value of torrefied woody biomass and its dependence on the degree of thermal decomposition. For experimental studies experimental setup was designed and manufactured. Experimental checking of the installation was carried out. The test showed that accuracy of determining combustion value is not more than 2 %. For experimental studies of the dependence of combustion value on the degree of thermal degradation, samples of wood were prepared in its unsaturated decomposition. Heat treatment of samples was carried out in inert gas environment of helium. Values of heat combustion of wood fuel with varying degrees of thermal destruction are obtained. Model of the dependence of calorific value from relative mass of wood fuel ω is proposed. The mathematical model allowing to determine the relative mass of wood as a function of temperature and time is represented. Dependence of combustion value on degree of thermal decomposition of wood is obtained in explicit form.

Several variants of a low-energy storage ring for Thomson scattering X-ray source were considered in *. The most promising variant "C" of the ring with small dimensions and large dynamic aperture has also large momentum compaction factor, which would lead to too long bunches with RF cavity operating at 714 MHz, so shorter wavelength must be used. In this paper we present results of optimization of S-band double-cells cavity with parasitic mode damping by chokes similar to **. Interaction of the bunch circulating in the ring with cavity parasitic modes is simulated.

Regulation of the waveguide coupling factor of standing wave linear accelerator allows to adjust the value of accelerated current, keeping the reflected RF power close to zero. This ensures the most efficient use of RF energy and absence of overvoltage in the waveguide elements. The paper presents studies results for various methods of coupling factors regulation with continuous wave (CW) normal conducting linear accelerator used as an example. The results of calculations and measurements on the mock-up of the accelerating structure are presented.

At steady low-luminosity states, Supergiant Fast X-ray Transients (SFXTs) can be at the stage of quasi-spherical settling accretion onto slowly rotating magnetized NS from the OB-companion winds. At this stage, a hot quasi-static shell is formed above the magnetosphere, the plasma entry rate into magnetosphere is controlled by (inefficient) radiative plasma cooling, and the accretion rate onto the NS is suppressed by a factor of \sim 30 relative to the Bondi-Hoyle-Littleton value. Changes in the local wind velocity and density can only slightly increase the mass accretion rate (a factor of \sim 10) bringing the system into the Compton cooling dominated regime and led to the production of moderately bright flares (L_x\lesssim 10^{36} erg/s). To interpret the brightest flares (L_x>10^{36}~erg/s) displayed by the SFXTs, we propose that a larger increase in the mass accretion rate can be produced by sporadic capture of magnetized stellar wind plasma. At sufficiently low accretion rates, magnetic reconnection can enhance the magnetospheric plasma entry rate, resulting in copious production of X-ray photons, strong Compton cooling and ultimately in unstable accretion of the entire shell. A bright flare develops on the free-fall time scale in the shell, and the typical energy released in an SFXT bright flare corresponds to the mass of the shell. This view is consistent with the energy released in SFXT bright flares (\sim 10^{38}-10^{40}~ergs), their typical dynamic range (\sim 100), and with the observed dependence of these characteristics on the average unflaring X-ray luminosity of SFXTs. Thus the flaring behavior of SFXTs, as opposed to steady HMXBs, may be primarily related to their low X-ray luminosity allowing sporadic magnetic reconnection to occur during magnetized plasma entry into the magnetosphere.