The research is devoted to the study of the soil and plant complex of the monument of landscape architecture of the XVIII century – the park «Dubki» in St. Petersburg, located on the northern coast of the Gulf of Finland in the Resort area of St. Petersburg, in the city of Sestroretsk. The park was created on the initiative of Emperor Peter the Great, who, during his return from the Battle of Gangut, made a stop among an oak grove on the shore of the Gulf of Finland. Currently, the park is recognized as a monument of cultural and historical heritage, protected by UNESCO. In the summer of 2021, the morphology of the soil, the species diversity of coniferous, deciduous species and shrubs were studied at the facility. The morphology of the soil was studied by 2 soil sections laid down in various forest growing conditions. The species composition of park plantings was determined by the plant determinant [Kiseleva et al., 2020], using morphological features of leaves and bark. With the use of the RGIS and AutoCAD software complexes, the areas of the park's land under vegetation, under paths, artificial reservoirs, sports grounds, etc. are calculated. Based on the results of the research, recommendations are given for maintaining the balance and sustainable development of the soil and plant complex and information on the development of the land cadastre of the park.

Remote registration of such taxation indicators of trees as crown width and tree height has become widespread in assessing the biomass of trees. There are many allometric models of the biomass of different tree species in different climatic conditions, but for the assessment of biomass by remote methods, they are presented in single publications. The authors used the experimental data base of 249 and 78 model trees of Fagus spp. and Fraxinus spp. correspondingly with measured indicators of tree height, crown width, as well as the biomass of trunk, foliage, branches and roots. For all components of aboveground biomass, a positive relationship was established with the crown width and the tree height. Two-input tables for the taxation of the biomass of two genera are compiled. The results obtained give an idea of how much the biomass structure of equal-sized trees of such species as beech and ash can differ, whether this structure can change in the winter temperature gradient of Eurasia, and what can be the contribution of the climate variable to the explanation of the variability of tree biomass.

The relationship between the height and age of the stand is the basis for assessing the productivity of the growing area. Among the numerous methods for constructing site index scales, the generalized algebraic difference approach has become increasingly widespread in recent years due to the ability to vary several parameters of the basic growth function and thereby obtain polymorphic curves that are invariant with respect to the base age, specific for each level of stand productivity. The aim of the study is to model the growth of pine forest plantations along the average height using various equations (anomorphic and polymorphic curves, with constant or variable asymptotes) using a generalized algebraic difference approach and the development of a dynamic site index scale. The study uses data from measurements of stands on 89 permanent sample plots in pine forest cultures of the Forest Experimental Station of the RSAU-MTAA (Moscow). The study analyzed 25 equations obtained using the generalized algebraic difference approach. The general asymptotic polymorphic equation for the basic Richards (Mitscherlich) function with the replacement of the parameter responsible for the shape of the curve was adopted as the best model. Since all the studied forest stands are in similar soil and climatic conditions, a general asymptote appears regardless of the initial growth parameters. After removing the age trend, cyclical fluctuations were revealed in the residuals, which indicates the presence of wavelike periods of growth. The model is suitable for use in the age range from 10 to 150 years. In all cases, the modeled growth curves at average height reflect the dynamics of the actual stands.

The growth rates of seedlings of Schrenk spruce (Picea schrenkiana Fisch. & C.A. Mey.) in containers in open ground conditions with artificial irrigation were studied. The purpose of the research is to establish the effectiveness and determine the prospects for the introduction of the Shrenk spruce into the Nizhny Novgorod region. The object of research is four-year-old seedlings of Shrenka spruce, obtained from normal seeds from natural plantings in the south-east of Kazakhstan in the central part of the Trans-Ili Alatau. The vector of introduction transfer was 13°13'43" north latitude and –33°18'53" east longitude; the height difference reached 2664 m. The hypothesis about the possibility of the introduction of Schrenk spruce into the Nizhny Novgorod Volga region was based on the distribution in the region of natural stands of Norway spruce (Picea abies (L.) H. Karst.) and Siberian spruce (Picea obovata Ledeb.), which in the area of transgression of habitats form fertile interspecific hybrids known as Finnish spruce (Picea ×fennica (Regel) Kom.). The typicality, suitability, expediency and reliability of the experiment are ensured, the principle of a single logical difference and a randomized assignment of plants to the sample is implemented. The differentiation of seedlings according to the parameters of the aboveground part was established: in height Cv = 26.91% (10.53 ± 0.23 cm); in diameter Cv = 35.20% (2.52 ± 0.07 mm). The correlation of the characteristics of the aboveground part of the seedlings of Schrenk spruce was found. The height of the aboveground part had a high closeness on the Cheddock scale with the number of lateral branches on the central shoot and the total length of the lateral branches in the aboveground part: r±mr = 0.705±0.057 (tr = 12.38) and r±mr = 0.728±0.055 (tr = 13.20). This is described by regression equations: y = 0.551x + 6.257; (R² = 0.49719) and y = 0.114x + 7.617 (R² = 0.5294). The compliance of seedlings with the requirements for the rates of ontogenetic development of this tree species was noted. The level of growth and development of the aboveground part of the Schrenk spruce seedlings in the open ground of the nursery indicates a sufficient resource for seed propagation of the natural conditions of the region and a significant potential for its introduction to the Nizhny Novgorod region.

The aim of the study is to develop a mathematical model of rut formation on a forest soil, taking into account its partial elastic recovery with a decrease and removal of a periodic load, as well as its’ limited plastic deformations. The rheological model of the Bingham body was used as a theoretical basis for the development of the model. The numerical values of the model parameters are taken on the basis of the results of experiments to determine the mechanical properties of forest soils, carried out previously. To assess the limiting value of the model deformation, the results of previous studies were used to determine the rut depth basing on the methods of terramechanics and the theory of off-the-road locomotion. The proposed model was implemented in the Maple 2017 program; the solutions were obtained numerically by the Runge-Kutta method. The calculations show that the use of a variable plasticity limit, which increases in proportion to the deformation, makes it possible to take into account the limitation of the plastic deformations of forest soil, which qualitatively corresponds with the known experimental data. This distinguishes the proposed model from common elastic-viscous and elastic-visco-plastic models. In the future, the results obtained are planned to be integrated into mathematical models that reveal the dynamic effect of forestry machines on soils linked with vibrations during their movement, obstacles encountering, and trees processing. A separate area of further research consists in modeling the behavior of nonlinearly strengthening soil under the influence of forest machines.

Logging is one of the most dynamic economic sectors in our country. At the moment, the methods of timber harvesting have undergone significant changes. Instead of manual labor, various devices and devices are used, including hydraulic manipulators for the forest. The manipulator-type equipment (hydraulic manipulator) is a mechanism that is installed on cars, tractors, specialized vehicles, as well as stationary. The efficiency of using machines and equipment is directly dependent on their technical condition, readiness to reliably, efficiently and safely carry out the processes of logging production. The condition of machines and equipment depends not only on their technical level and compliance with operating rules, but also on the quality of their design. Dynamic research of volumetric hydraulic drives of forest machines occupies an important place in the process of their design. In engineering practice, at the stage of both preliminary analysis of the dynamic characteristics of volumetric hydraulic drives, and at the stage of preliminary design, their linearized mathematical models are widely used. The article considers linearized models: a cyclic hydraulic drive with throttle control, an actuator for a hydraulic servo drive of a forest machine manipulator, a hydraulic servo drive with mechanical control. The results of a study of the stability of a servo hydraulic drive with mechanical control are presented. An expression is derived that determines the stability of a hydraulic servo drive with mechanical control, including the slip coefficient of the generalized hydraulic characteristics of the spool and the flow rate gain, which makes it possible to find their values corresponding to the steady state of a hydraulic drive with mechanical control. The results obtained can be used in the process of designing hydraulic manipulators of forest machines, both at the stage of preliminary design and at the stage of technical design and obtaining the amplitude-phase frequency characteristics of the hydraulic drive of forest machines.

The skidder is one of the most important types of forestry it requires a competent approach to the design process, which of this type of equipment is one of the most important types of forestry machinery. One of the most loaded part of wheeled skidders is the transmission, which it experiences significant loads in the process of operation. To record and to measure the values of these loads depending on the gear, on which the process of skidding a pack of trees is carried out. Which the process of skidding a pack of trees is carried out, were carried out tests of the skidder TLK-1, which took place on the firing ground Onega tractor plant. As a result of tests were determined values of torques on axles and cardan shaft of the skidder on different gears, as well as the time of using each of the gears. The data obtained during the tests were processed using the methods of stochastic mathematical modeling. As a result, a mathematical model mathematical model to predict the usage of gear ratio of a wheeled skidder transmission equipped with hydrodynamic transmission. This methodology allows to estimate the correctness of the choice of the transmission ratio at the design stage. Design stage to assess the correctness of the choice of the transmission gear ratio.

Heavy forest machines disrupt the forest soil structure, for this reason, researchers pay considerable attention to the impact of forest machines on the movement surface. The rut depth after the first pass of the machine is one of the most informative indicators of the ecological impact. At the same time, relatively few studies are known, the results of which reveal the impact of wheeled skidders on the soil. To improve the process of skidding, further developments are needed to assess skidders environmental compatibility with forest soil conditions, which is the subject of our work. When performing the work, information about performance characteristics of skidders Tigercat, John Deere, Weiler, obtained from the official websites of manufacturers, was used. The rut depth was estimated using the principles of soil mechanics and the theory of off-the-road locomotion. The mathematical model of rut formation is implemented numerically. When processing the simulation results, data approximation methods were used. As a result of the study, models were obtained that allow in practice to assess the ecological compatibility of the skidder with forest soil conditions. The models use following characteristics of the machine: weight, number of wheels, width and diameter of the wheel, tire pressure, grapple opening area. The soil is characterized by its’ bearing capacity or cone index. The models take into account the average volume of a tree skidded in the bundle. According to the obtained models, it is possible to solve an inverse problem: justification of the permissible mass of the machine and the grapple opening area, taking into account the characteristics of the mover and the soil conditions.

The composition of wood raw materials was investigated at four chipboard plants with a capacity of 100, 120, 200 and 480 thousand m3 of boards per year. Currently, the main raw material for board factories is solid stem wood in the form of firewood and pulpwood. Its share is 63...100% of all raw materials, the average value for four plants is 70.2%. The rest of the raw material is waste from various wood-processing industries. The proportion of used waste increases with an increase in the capacity of the board plant from 0 to 32.0%. On average, the consumption of waste is as follows: imported chips 4.7%, slab 10.9%, sawdust 7.1%, waste from veneer and plywood production 4.3%, waste from board production 1.2%, recyclable materials 1.6%. Plants with a capacity of up to 120 thousand m3/year use waste that does not require the creation of additional technological sections for the preparation and processing of raw materials: slab and imported chips. They are processed in the basic technologies for making wood particles. Plants with a capacity of 200 and more thousand m3/year use not only slab and imported chips, but also other types of wood waste: sawdust, waste from the production of veneer, plywood, boards, and recyclable materials. They require special technologies for their preparation in new areas, which include technological and transport equipment. When planning the use of woodworking waste, it is necessary to take into account the peculiarities of each type of waste, which limit the upper level of their share in the composition of raw materials. In pine slab, the bark content is 38.2%, which is 3.9 times higher than in stem wood. A significant increase in the proportion of bark in the slab leads to a decrease in the strength characteristics of the slab. In addition, the bark of the slab may contain mineral impurities and pieces of metal. They get there during the harvesting, transportation and storage of the sawlogs. The average length of sawdust particles does not exceed 5 mm. Only microchips for the outer layers of the slab can be made from such raw materials. The composition of coniferous and deciduous raw materials is approximately the same: the share of conifers is 46.8%, deciduous 53.2%. The bulk of deciduous raw materials are firewood and pulpwood (47.8 out of 53.2%). Coniferous raw materials mainly come in the form of wood processing waste (wood chips, slabs, sawdust). The use of pine and spruce is roughly equal. Aspen predominates among deciduous species – 38.2% versus 15.0% for birch. This is due to the fact that the bulk of the firewood supplied to the enterprise is aspen trunks. Comparison of the consumed raw materials at present and in 1984 shows that the share of the main raw materials, firewood and pulpwood, is maintained practically at the same level of 70.2 and 68.1%. Consumption of imported wood chips decreased by 3.6 times from 16.9 to 4.7%. The use of waste wood processing industries (slab, sawdust, waste veneer and plywood), on the contrary, increased 1.7 times from 13.1 to 22.3%. As a result, the share of coniferous wood in the composition of modern raw materials has almost doubled from 23...25% to 46.8%, and the share of deciduous species has decreased from 75...77% to 53.2%.

In the course of studies, it was found that the curing of urea-formaldehyde resins (UFR), with the formation of a spatially crosslinked structure, at a molar ratio of formaldehyde to urea less than one, occurs due to the formation of an inert compound – methylenediurea (MDU). For the experiment, the laboratory UFR (LUFR) was synthesized according to the following scheme. In the first stage, the molar ratio of urea : formaldehyde (U : F) = 1 : 2. The pH value is 7.5...8. At the second stage, the pH is 4,2...4,5. The third stage is the introduction of additional urea to the molar ratio U : F = 1 : 0.9, the pH is 7...8. The synthesis of MDU was carried out at a molar ratio of U: F = 1: 0.5. Urea was introduced into the formalin solution (pH 3), with constant stirring, and the latter was completely dissolved at 20 °C. After that, the reaction temperature was raised to 50 °C, and kept until a dense precipitate was formed. The resulting precipitate was washed on a paper filter with distilled water until a neutral reaction. The sample was dried at 105 °C to a constant mass. In a slightly alkaline environment, at the third stage of synthesis, when urea is introduced to the molar ratio U : F = 1 : 0.9, monomethylolurea is formed, which under acidic curing conditions will react primarily with urea, which is in a significant excess. This leads to the formation of MDU. Moreover, the latter does not enter into either the addition reaction with formaldehyde or the condensation reaction with the hydroxymethyl groups of UFR. As a result, MDU does not participate in the formation of the polymer structure, being an inert filler, and its components by weight, urea and formaldehyde, can be excluded from the final molar ratio. Thus, at the initial molar ratio of the initial components U : F = 1 : 0.9, during a series of chemical transformations, the final molar ratio increases to U : F = 1 : 1.012,which allows the formation of a spatially crosslinked polymer.

This research is aimed at creating drugs that inhibit the growth of the microorganism Staphylococcus epidermidis, which causes difficult to treat diseases. The study shows a successful attempt to synthesize natural esters – coumarates of sesquiterpene alcohols from sesquiterpene compounds of birch buds. The chromatographic and mass spectrometric characteristics of the obtained compounds coincide with the characteristics of natural ones. Control over the quality and quantity of intermediate and final products was carried out by gas chromatography-mass spectrometry. The resulting products showed retention times and mass spectra corresponding to natural values. The synthesis included the preparation of a vegetative buds extract, saponification of sesquiterpene alcohol acetate, vacuum distillation of the sesquiterpene alcohol fraction, preparation of coumaric acid acetate, oxalyl chloride, coumaric acid acetate chloride, esters of coumaric acid acetate and sesquiterpene acetyl alcohols, hydrolysis and chromatography of products with silica gel. The product yield, calculated as sesquiterpene alcohols, was 70%. The synthesized compounds, as well as natural ones, showed antimicrobial activity against Staphylococcus epidermidis with a MIC = 1000 μg / ml. The estimated antimicrobial activity was 20 times less than the activity of natural coumarates of sesquiterpene alcohols. The composition of the obtained products differed from natural compounds by the absence of one of the main components – -betulenol coumarate. -Betulenol is absent in free form in birch buds.

When As₂Se₃ glass is doped with tin, lead, or bismuth, isothermal bulk crystallization of the resulting glasses under optimal conditions is possible. The influence of bismuth concentration on the character and kinetic parameters of glasses crystallization has not been studied sufficiently. The purpose of this work is the comparative analysis of the kinetics of isothermal volumetric crystallization of As₂Se₃ and AsSe_1,5Bi_x glasses (x = 0,01 and 0,05). Glasses were synthesized by vacuum melting method from especially pure elemental substances with total mass of 7 g in the interval 700–900 С with the subsequent quenching of quartz ampoules with melts in air from 700 С. The kinetics of transformations during bulk isothermal crystallization of AsSe_1,5Bi_0,01 and AsSe_1,5Bi_0,05 glasses in the temperature range 210–260 С wаs studied by methods of density, microhardness, temperature dependence of electric conductivity, X-ray phase analysis of quenched samples. Analysis of the kinetics of bulk crystallization of the glasses was performed according to density measurements using the generalized Kolmogorov–Avrami equation. The addition of 2 at.% Bi to As2Se3 glass accelerated the crystallization of the main As₂Se₃ phase, reducing the latent period of the onset of As₂Se₃ phase separation by about 4 times and the kinetic period of half-transition by 13 times in comparison with the crystallization of pure As₂Se₃ glass. The effect of 0,4 and 2 at.% Bi additions on the isothermal crystallization of As₂Se₃ glass manifests itself mainly in decreasing the thermodynamic barrier and activation energy of bulk heterogeneous nucleation of lamellar As₂Se₃ phase crystals on primary Bi₂Se₃ phase nanocrystals. The reconstructive crystallization of the main phase of As₂Se₃ in AsSe_1.5Bi_0.05 glass is associated with a continuous change in the chemical composition of the residual glass phase and is characterized by an interval of decreasing values of the effective activation energy (142 → 114 ± 5 kJ/ mol).

The object of work is the bearings of the drying cylinders of the cardboardmaking machine. The subject of the work is temperature diagnostics of the technical condition of the bearings of drying cylinders. The purpose is to develop a method for calculating the permissible temperature levels of bearings of drying cylinders and the use of permissible temperature levels to assess the technical condition of bearings. During the period of operating time, the wear of the rubbing surfaces of bearing parts is accompanied, by the formation and development of defects. Defects increase the friction forces between the rubbing parts and the temperature of the bearings. The temperature of the bearing housings is considered as a structural parameter of the technical condition of the bearing. Experimental studies of the temperature of the bearings of drying cylinders under the steady-state operation of the cardboard-making machine have been carried out. The calculation of the total measurement error of instruments and instruments was made. The reproducibility of temperature diagnostics was established by checking. The deviating temperature levels of individual bearings of the examined array have been clarified. The calculation determines the average and permissible temperature levels of bearings separately from the front and drive sides of the drying groups for steam supplied to the drying cylinders. According to the processed data of experimental studies it was found that the bearings on the front side in each of the groups of pairs have an arithmetic mean temperature level 7...9 C lower, than on the drive side. The arithmetic mean temperature level of the bearings of drying cylinders increases from the third group of steam to the first. The temperature difference between adjacent groups is 5...9 C, and between the first and third groups reaches 20...21 C. Thus, a method of temperature diagnostics of bearings of drying cylinders of a cardboard-making machine has been developed and tested. Diagnostic measurements were carried out and the permissible temperature levels of bearings with two-way restriction were calculated. According to the permissible temperature levels, the technical condition of the bearings was assessed. 4 bearings with the rating "unacceptable" were found. The proposed method of temperature diagnostics satisfies the conditions of reproducibility and ensures the detection of faulty bearings in the operating mode of the equipment.

The article deals with physical and chemical methods that determine the polymerization completeness of epoxy oligomers. New terpenoid products are presented as curing catalysts. The phase transition of epoxy oligomers from soluble to polymerized state is studied. It is known that epoxy oligomers in polymerized state have a small number of cross-links located at a sufficiently large distance from each other, and chain segments between the cross-links have some mobility. The presence of hydroxyl groups in the oligomer macromolecules makes it possible to create composites characterized by high adhesion properties to a variety of materials. The IR spectroscopy method is used to control the quality of polymerized composites. It allows to determine the composition change and polymerization completeness. In the course of research it was found that the IR spectroscopy method can be used to determine the polymerization completeness of epoxy binder by secondary terpenoid products. On the registered spectra there are changes in the area of absorption bands belonging to anhydride and epoxy groups. These bands completely disappear in comparison with similar bands in the spectra of the original binder components. New absorption bands characteristic of ester groups – ν(С=О), νas С–О–С и νs С–О–С – were found in the IR spectrum of the composite. The intensity ratio of aromatics absorption bands in the spectrum of the composite, -CH₃ groups practically remains the same as in the spectrum of the epoxy oligomer, which confirms the nonparticipation of this oligomer part in the polymerization process. The conducted studies made it possible to adapt the method of IR spectroscopy to determine the polymerization reaction completeness of epoxy oligomer by secondary terpenoid products.

The paper deals with issues related to the CСM technology for the collection and storage of biological substances, these technologies and their manufacturers. Studies of the properties of samples of CСM from different manufacturers have shown that the cotton fiber of which they are composed has low indicators of the weighted average length (1.0–1.2 mm) at the beating degree of 18–20 oSR. Studies of samples of FTA cards for absorbency have shown that the samples have a high rate of absorption of a drop of water on the surface (on average 0.5 sec.) and not high capillary absorbency (6.5 cm), which is necessary for the effective operation of the material for collecting and storing samples of biological substances. Investigation of the physical-mechanical properties of imported samples of cards for the collection and storage of biological materials have shown that the cards have not high indicators of breaking length (1.3–1.5 km) and bursting strength (74–100 kPa), which simplifies the procedure for extracting a biological sample by punching. Investigation of the influence of the technological parameters process of refining (mass concentration, refining time) on the properties of CCM made it possible to determine the optimal modes of refining cotton cellulose, providing quality indicators similar to the properties of imported samples of FTA cards. It is shown that in order to achieve morphological parameters of fiber and properties of CCM similar to those of imported samples of FTA-cards, the refining of cotton pulp in a roll must be carried out at a mass concentration of 3 to 4 g / l with a pressure on the lever and a beating degree of 16–18 °SR.

We explored phase change memory phenomena in thin film of chalcogenide-glass semiconductors GST225 by passing through the film a sequence of triangular current impulses with increasing amplitude. Initially the film was in amorphous state. We took simultaneous oscilloscope pictures of the voltage across the thin-film “sandwich” type sample and the current passing through the above unit as a function of time. Then we got the current-voltage characteristics of the unit done. Distinctive features observed on some of the oscilloscope pictures and current-voltage characteristics are places with rapid decrease in voltage and negative differential resistance. After passing current impulse with the biggest amplitude the current-voltage characteristic of the unit is becoming almost ohmic. Analysis of all the current-voltage characteristics obtained allows us to suggest that the memory state formation apparently occurs in stages with gradual crystallization of amorphous substance of the film on thickness depending on amplitude of the triangular current impulses passing through the unit. This possible scenario is discussed here only from qualitative point of view. The rapid decreases in voltage apparently can under certain conditions be explained by peculiarities of crystallization process (“explosive” crystallization) while crystallization itself is initiated by electrical field. Taking also into account that under injection of current, when the film is in poorly conducting state, a space charge appears to form and as consequence a nonuniform distribution of field on thickness of the film can arise we can assume that crystallization starts at one of electrodes where the field is the biggest. “Explosive” crystallization of amorphous substance dies down when the field near the front of crystallization turns out to be not enough for holding it. After a part of the film is crystallized such a way and conditions for “explosive” crystallization are not more fulfilled the further crystallization can run by heating. As to a part of current-voltage characteristic with negative differential resistance they apparently are connected with switching phenomena that is characteristic of amorphous chalcogenide semiconductors.

Glassy germanium and gallium chalcogenides have a wide range of practical applications. Transparency in the IR region of the spectrum, low sensitivity to impurities, and high chemical stability make these amorphous materials promising for the needs of the electronics industry. Chalcogenide films MnCl₂-GeS₂-Ga₂S₃ and MnS-GeS₂-Ga₂S₃ were synthesized from the solutions of chalcogenide glasses in nbutylamine and also the specific electroconductivity of films has been investigated. The deposition of amorphous films was carried out according to the previously developed Baidakov–Shkolnikov method. For the measurements of specific electroconductivity values the AC and DC methods are used. The charge transfer activation energy and the pre-exponential factor were calculated using an Arrheniustype equation. The specific surface resistance was determined from the ratio of the product of the surface resistance of the sample and the contact length to the distance between the contacts. The specific surface electrical conductivity of the films was taken as the reciprocal of the specific surface resistance. With in increase in the manganese salts content in the chloride and sulphide systems an increase the absolute values of the electroconductivity are observed. It was found that germanium and gallium chalcogenides concentration rations in the glass-forming network of bonds are important for conductivity level in films. The electroconductivity of chalcogenide glasses and films of a similar composition practically do not differ. The chalcogenide glasses mechanism of dissolution in aliphatic amines is explained the similar electroconductivity parameters of glasses and films.

The modern system for standardizing the load on water bodies consists of three main elements: 1 calculation of technological standards for marker substances for the industry; 2 calculation of permissible discharge standards for substances of 1 and 2 hazard classes; 3 comparisons of the calculated standards of permissible discharges with the standards of permissible impacts for water management areas established on the basis of the decision of the state ecological expertise. The formulas given in the methodology for calculating the permissible discharge standards have a limited range of application. The paper proposes an algorithm for calculating the convectivediffusion transfer of pollutants from the wastewater discharges of Silvamo Corporation Rus into the Vuoksa river in the Lesogorskoye reservoir area. For the study, the main outlet of the enterprise was chosen, through which purified wastewater containing residual pollutants from the main production and wastewater of the city of Svetogorsk is discharged. The Vuoksa River is extremely heterogeneous in the area of wastewater discharge through the outlet. Therefore, the calculation of the transfer of pollutants according to the current method for calculating the permissible discharge standards ignores the formed alongshore stagnant zones and wind currents prevailing in these zones. For the calculations, a combined model of the transport of pollutants was proposed, taking into account two-dimensional and three-dimensional models of wind currents and models of convective-diffusion transport and transformation of substances. When calculating the concentration field according to the official method for calculating the permissible discharge standards, the length of the pollution spot was 15 meters, and according to the proposed calculation algorithm, taking into account the relief of the coastal zone and the direction of wind currents, 140 meters. For the release of Silvamo Corporation Rus with fine water into the Vuoksa River, the results of calculating the standards for permissible discharges according to the current methodology and based on the developed combined model of convective-diffusion transport of pollutants are presented, which gives heterogeneous results. According to the developed allowable model, the concentration of BOD in wastewater is 1.7 times higher than the required value according to the current methodology for calculating standards, discharges are allowed. The application of an individual approach to the calculation of standards for permissible discharges makes it possible to determine environmental standards for water quality in water bodies and determine the maximum levels of load from a pulp and paper mill.

The possibility of improving the efficiency of deinking «МС-7Б» grade recovered paper from toner applied on a laser printer by dry two-stage dispersion before flotation was investigated. Recovered paper was used with a different level of toner print on one side of the paper: 2.5%; 3,9%; 8,2%; 60%. The degree of toner prints of office recovered paper was determined by the program «lpSquare v5.0 for Windows» as the ratio of the area of the printed area to the total area of the sheet in %. The level of cleaning recovered paper from toner embossments was determined using a graphic program that made it possible to establish the area of the black area. It has been that the developed recovered paper stock preparation technology involving two-stage dry dispersion and subsequent flotation effectively removes toner print area in paper samples. Toner print area in samples of paper obtained from floated recovered paper with preliminary two-stage dry dispersion are practically absent, unlike samples of paper from recovered paper ennobled with standard flotation. Assessment of mechanical properties of paper samples was carried out by changing the values of bursting and tinsel strength. It is shown that preparation of recovered paper stock by method of flotation with preliminary dry dispersion contributes to small increase of mechanical indices of paper samples. The mechanical properties of paper samples practically does not depend on the level of toner print area of recovered paper.