The article discusses the features of natural renewal under the canopy of pine ecosystems in the Moscow region. 20 observation plots located in the Moscow Educational and Experimental Forestry and the Losiny Ostrov National Park were surveyed. The selected research objects are of age class – IV, site index class I-Ia. It has been established that in the Moscow Educational and Experimental Forestry over the past 70 years, the species composition has not changed dramatically. Over the past 170 years, the share of pine in the historical part of the Losiny Ostrov National Park has decreased from 25% to 8%. Over the past three years, the average annual growth of spruce undergrowth does not exceed 5 cm. There is a succession change of pine phytocenoses to deciduous ones, which subsequently can lead to the formation in the Losiny Ostrov National Park of stands of species composition and structure that are radically different from those currently existing. Picea abies (L.) H. Karst is the predominant species in the undergrowth of the studied pine forests of the Moscow Educational and Experimental Forestry. Picea abies (L.) H. Karst. Acer platanoides L. dominates in the undergrowth of Losiny Ostrov, the presence of an invasive species, Acer negundo L., was revealed. In the studied pine formations, there is no viable undergrowth of Pinus sylvestris L. Sorbus aucuparia L. Predominated among the undergrowth species in the Moscow Educational and Experimental Forestry, and Euonymus europaeus L. and Rhamnus frangula L. dominated in the Losiny Ostrov National Park. The set of tree and shrub species in the lower tiers is rather limited.

Studies have been conducted in different countries and under different ecological conditions to assess the productivity of mixed stands. The results of these comparative studies show that mixed stands tend to be more productive than pure stands, with optimal combinations of tree species having the greatest effect. This is accomplished by enhancing the growth of the main species and increasing the productivity of several species in a mixed stand. Studies also show that interspecific competition is weaker than intraspecific competition, with the greatest effect.

The article presents the materials of structural characteristics and snow-retarding capacity of protective forest strips (FSRs) functioning along the Yekaterinburg – Kamensk-Uralsky railway line. The strips were created in 1936 and 1956 of an impervious design. Currently, the overmatured birch and poplar ZLPs along this line have an openwork design. Their snow retention capacity is extremely poor. Snow accumulates not in the strip and its edges on the windward and leeward sides, as it was supposed in the creation of the strips of windproof construction, but is distributed quite evenly between the ROW and the railroad. In this part of the railroad right-of-way, the snow cover height is characterized by consistently high values, in most cases exceeding the values in the open field. In the investigated areas, snow density varies in a fairly narrow range from 0.13 to 0.17 g/cm³. No strict regularities in changing the value of this indicator depending on the location of measuring points relative to the railroad are detected. In general, in order to increase snow-retarding properties as well as stability and durability of ZLP, it is necessary to carry out appropriate maintenance, aimed at preserving and strengthening the snow-retarding function in them.

The aim of the work was to improve the regulation of the composition and density of forest stands by injecting herbicides and their mixtures into the trunks of hardwood trees to increase silvicultural efficiency, reduce the chemical and toxic load on forest ecosystems. The objects of research were individual trees of gray alder and aspen of vegetative origin in the pole stage in mixed stands. As a result of the analysis of domestic and foreign literature on the problem, promising herbicides for study were selected – tornado (aqueous solution, 360 g/l glyphosate in the form of isopropylamine salt) and arbonal (water-soluble concentrate, 250 g/l imazapyr) and field experiments were laid with selected herbicides. In four field experiments, the biological effectiveness of the action of herbicides and their mixtures on gray alder and aspen trees in mixed plantations was determined. As a result, the high efficiency of the herbicide arbonal at doses of 0.08 and 0.16 ml/tree, as well as mixtures of tornado (0.12–0.25 ml/tree) + arbonal (0.06–0.08 ml/tree) was established on gray alder. According to the effect on aspen, the most effective was the use of tornado 0.20 ml/tree and 0.55 ml/tree), arbonal (0.16 ml/tree) and mixtures of tornado (0.20 ml/tree) + arbonal (0.08 ml/tree) and tornado (0.25 ml/tree) + arbonal (0.06 ml/tree). Alder gray showed greater resistance to the applied herbicides in the year of treatment, but we should expect an increase in the effect of herbicides in the next growing season. It has been established that the use of herbicides tornado and arbonal, as well as their mixtures in various combinations, is very promising for the suppression of unwanted woody vegetation by injection in mixed stands.

The GHG standard implies a set of rules and procedures for the greenhouse gas (GHG) assessment. The most prominent standards include VCS (Verified Carbon Standard), CCB (Climate, Community and Biodiversity), VCS+CCB, REDD.plus platform of the REDD+ mechanism, World Bank FCPF (Forest Carbon Partnership Facility), ART (Architecture for REDD+ Transactions) TREES (The REDD+ Environmental Excellence Standard), CAR (Climate Action Reserve), and GS (Gold Standard). For comparative analysis, these standards are analyzed and evaluated against a series of criteria. These criteria are: Baseline, Additionality, Permanence, Leakage, Uncertainty, Nesting, Double Counting, Safeguards, Registry, Monitoring and Verification, Governance and Accounting, Human Rights. Comparative analysis provides basis for the evaluation of the carbon credits traded in the current carbon markets.

The reduction of species diversity in the process of logging and the solution of the issue of species conservation is of particular relevance for the Vologda region, the territory of which is almost 80% covered by forests, where clear cutting is carried out on a significant area. One of the directions of species conservation in the process of forest management is the identification of key biotopes. Indices of similarities and differences between plant communities can be considered as a tool for assessing species diversity. The aim of the work was to demonstrate the need for additional study of the species diversity of plants of forest communities when establishing the boundaries of key biotopes with excessive moisture in the process of forest management. The territories of five key biotopes preserved in the process of logging during clear-cutting were studied. At the same time, forestry-taxation and ecological-biological methods of field and office assessment were used. On the basis of detailed floristic descriptions using similarity and difference indices, an assessment of plant communities of living ground cover in individual elements of key biotopes – the core and the buffer zone – was carried out. The data obtained by the authors indicate that the distribution by abundance classes of the Drude scale is uneven (most species are not numerous); There is a higher level of species diversity in the buffer zone compared to the core of key biotopes. Analysis of the values of the indices of similarity (Jaccard, Sjørensen-Chekanovsky, Kul’chinsky) and difference (Stugren-Radulescu) indicates that the core and buffer zone of the key biotope «Ermolino» (a forest area on the edge of the swamp) have the greatest similarity, and the core and buffer zone of the «Novlenskoye» object (a forest area along a temporary watercourse) have the least identity. The buffer zone is characterized by a higher originality of species spectra. Thus, it is concluded that it is necessary to carry out environmental measures to preserve species diversity in the process of forest management, as well as to identify and preserve not only the central zone (core) of the key biotope, but also its buffer zone as the territory with the largest number of species.

When studying the structure of plant communities, only a description of the floristic composition is insufficient, but it is necessary to identify functional relationships between individual plant species, between plants and the environment, the abundance and ecological-coenotic groups of species. The purpose of the study is to identify the features of the vegetation cover of forest phytocenoses according to observations on permanent sample plots in the conditions of the Kologrivsky Forest Nature Reserve (Kostroma region). The object of the study was 34 permanent trial plots laid out on the Kologrivsky (28 trial plots) and Manturovsky areas of the reserve (6 trial plots). The study used survey data from 2018–2022. The analysis of geobotanical descriptions on the permanent sample plots of the Kologrivsky Forest Nature Reserve made it possible to identify seven main groups according to the common vegetation cover, each of which is characterized by an individual ecological and coenotic spectrum: i) pine formations with a predominance of heather in the herbaceous layer of the Manturovsky area, ii) linden-elms spruce forests, iii) native spruce forests and plantations derived from them in places of old clearings, iv) forest stands in areas with disturbed soil cover with a predominance of the meadow-edge ecological-coenotic group, v) spruce stands with a disturbed structure of the upper canopy and vi) forest stands on areas with disturbed soil cover with a predominance of boron ecologicalcenotic group; vii) blueberry pine forests of the Manturovsky area. Ordinations of geobotanical descriptions in abstract axes of factors according to D.N. Tsyganov ecological scales made it possible to distinguish two main groups of habitats: i) with strongly acidic/acidic soils, very poor/poor nitrogen in perhumid climatic conditions, where the received solar heat is not enough to evaporate the incoming moisture; ii) with acidic/slightly acidic soils poor in nitrogen, belonging to the euhumid ecological group. On the sample plots under study, observations should be continued to identify dynamic processes in the composition and structure of the vegetation cover without the impact of anthropogenic factors under the conditions of the protected regime of the territory.

The object of the study is lingonberry and lichen pine forests growing on different relief elements. Accounting was carried out on circular accounting sites of 10 m². The biometric characteristics of the undergrowth were determined using methods generally accepted in forestry and taxation. It is shown that under the canopy of pine forests growing on dry, poor soils in the conditions of the Republic of Buryatia, the natural renewal of pine is unsatisfactory. The main part of the undergrowth grows in the «windows». Under the canopy of forest stands, there is mainly non-viable undergrowth, whose age is 3-8 years, the average height is less than 40 cm. The dependence of the average growth value, the number of branches in the whorl, the age of the needles on the age of the pine undergrowth and its height is also established. The total number of pine undergrowth does not exceed 1000 ind./ha. The share of unviable undergrowth reaches 42%. Undergrowth of the «dry» category is about 3%. The peculiarity of the natural renewal of pine under the canopy of forest stands on dry, poor soils is manifested in the fact that most of the undergrowth is found in windows. Under the canopy of forest stands, undergrowth is much less than in the «windows» and almost completely belongs to the «non-viable» category. The total amount of dry and non-viable pine undergrowth is almost 50% of the total number. The purpose of the study is to identify the features of the natural renewal of pine under the canopy of forest stands growing on poor dry soils and to establish the dependence of the main characteristics on the height and age of pine undergrowth.

The purpose of the presented work is a scientifically based selection of the most promising representatives of the genera Paeonia L. and Hosta Tratt. for their inclusion in the composition of flower arrangements on urban public facilities. Representatives of the genera Paeonia and Hosta from the collection fund of the Laboratory of Ornamental Plants of the Main Botanical Garden of the Russian Academy of Sciences were used as model objects. The genus Paeonia is represented by a sample of 19 cultivars with a Japanese flower shape, the genus Hosta is represented by a sample of 23 names. Comparative analysis of representatives of the genera Paeonia and Hosta and statistical processing of experimental data were carried out using standard techniques. The following standards were used: for representatives of the genus Paeonia – cultivars ‘Philomele’ and ‘Cora Stubbs’, for representatives of the genus Hosta – cultivar ‘Liberty’. The development of models of flower beds is carried out on the basis of generally accepted methods and techniques. The representatives of Paeonia and Hosta have the results of studies of their representatives on the signs that, in our opinion, are significant when using these plants on objects of urban landscape architecture. Representatives of Paeonia have five cultivars according to the complex of signs of the generative and vegetative sphere – ‘Philomele’, ‘Mrs. Wilder Bancroft’, ‘Cora Stubbs’, ‘Gay Paree’, ‘Lotus Queen’ and ‘Syurpriz’ – with priority for two cultivars ‘Cora Stubbs’ and ‘Philomele’, the most promising for use in urban landscaping. In the representatives of the genus Hosta, according to the totality of the four studied quantitative characteristics that do not have reliable statistical differences with the standard, were not revealed. But, based only on the results of the evaluation of the parameters of the leaf blade, three Hosta culrivars can be recommended for use as part of landscape compositions at urban public facilities: ‘Liberty’, ‘Frances Williams’ and ‘August Beauty’. Using representatives of the genera Paeonia and Hosta, selected based on the results of a comparative analysis of their quantitative characteristics, four compositions were designed.

The purpose of the study is to establish the regularities of the formation of maximum flow rates and erosion under the influence of forests, forest strips and agricultural lands in the steppe of the Volga upland. The research methodology was based on the recommendations of specialized research institutes and scientists of Russia. Water supply, runoff, maximum runoff modulus, erosion undergo significant changes under the influence of agricultural land, forest strips and forests. Forest strips and forests reduce the coefficients of spring and stormwater runoff in comparison with agricultural land by 10.5– 13.5 times, accordingly, the indicators of the maximum flow modulus are 5.1–31.0 times. The parameters of the drain module are necessary for the creation of discharge antierosion structures. Erosion under the influence of forest strips in fields with non-fallow technology of cultivation of crops of crop rotation of forest lands applies permissible sizes of less than 0.3 t / ha for soils A + B < 0.5 m. Dump technology, in addition to forest strips, requires the use of additional agrotechnical techniques, for example, mulched slitting. From the complex variety of the impact of natural and anthropogenic factors on erosion, the coefficient and modulus of surface runoff, the degree of protection of the soil by land are the predominant ones. Regression-correlation analysis notes a close relationship between erosion, surface runoff parameters and the forest strips used with the coefficient of determination of the relationship of features. Long-term studies on the slopes of 3–5° allowed us to recommend: the distances between the forest strips of 300 m, 250 m – a fall-free technology for cultivating crop rotation crops, the water flow module on agricultural landscapes for discharge erosion control structures has a 10% probability of exceeding 1.7m³/s×km².

According to the forest introduction zoning Voronezh region is included in the zone of medium potential, where the economic effect of forest introduction measures is supposed to be 15-25% higher than the effect of cultivation of native species. Here one of the promising nut-bearing conifers is tested pine flexible (Pinus flexilis James). The aim of the study is to consider in comparison with the conditions of natural habitat development and condition of bent pine in the territory of Voronezh region. It was found that flex pine surpasses Scots pine in ornamentality, being a species with a high degree of adaptability to arid conditions and frost-resistant. By the age of 49 years, there are restrictions on further growth of trees in height. The range of values of taxation indicators at introduction, as well as in the conditions of growth in the area, agrees with the opinion that the pine has a fairly high level of quantitative genetic variability within populations. Trees resistant to the pathogen (Cronartium ribicola) were identified. At the same time, abundant and frequent branching should be considered an unfavorable sign of tree development if it does not occur from the initial stage (6–10 years). The scheme of placement in the area (4,5 × 3 m) is quite acceptable, provided that there are 3 seedlings with a distance of 1 m between them in one planting place.

Experimental complex felling was carried out in pine forests of different ages on the drained upper peat bog 17 years after the construction of the canals. The oldgrowth part of the stand was completely removed, thinning was carried out in the young part. In most variants of the experiment, the increase in stock over 40 years of observation exceeds the corresponding control level. The largest increase in stock (11 m³/ha per year) was recorded in the area where the entire stand was removed simultaneously with drainage. For all experimental sites at the facility, the most important advantage, in comparison with the control variants, is the significant homogeneity of trees in terms of size and quality of trunks. At the control sites, trees of ripe and overmature age are characterized by stiffness, boughtness, inclination or bending of the trunk. To these defects was added a pronounced unevenness of the annual growth along the radius of the trunk.

The relevance of the theme is due to the large resources of wood in areas remote from centralized power supply and gas supply networks. Autonomous energy supply of such objects of the forestry complex can be organized using wood fuel. The aim of the study is to increase the efficiency of autonomous energy supply of timber complex objects by developing and optimizing wood-fired mini-power plants. The method is to numerical modeling. For this, a simulation model of a mini-power plant was developed using the SimInTech dynamic simulation program. We have made the numerical experiments using this mathematical model. The article presents a technological scheme of a mini-power plant based on an open cycle gas turbine, a Rankine organic cycle turbine and wood fuel gasification. The results of numerical simulation of the operation of a mini-power plant with an electric power of 3,8 MW in the SimInTech program using the tools of the Thermal Hydraulics module are presented. The main technological parameters of the power plant in the nominal operation conditions are calculated: pressures, temperatures and mass flow rates of working fluid flows of power plant cycles and heat carriers. We have also calculated the rated mechanical powers of the units: the compressor of the gas turbine plant and the gas turbine, the fan of the organic working fluid condensation system, the Rankine cycle turbine running on R113 freon, and the pump for supplying freon to the evaporator. The proposed model allows you to explore the operating modes of the power plant, with variable environmental parameters, to select the optimal design and operating parameters of the components of the mini-power plant. In particular, the dependence of the net efficiency of the power plant on the consumption of cooling air for the condenser of the organic working fluid was studied. As a result, the optimal values of the cooling air consumption were determined according to the condition of maximizing the net efficiency of the power plant. The obtained results contribute to further technological and constructive improvement of power plants. The results of the study can be used to substantiate the effectiveness and feasibility of projects for autonomous power supply of industrial facilities.

The article considers the issues of analyzing the movement of the elements of the vibration mechanism of the gripping and shearing device, which provides dynamic retention of the tree in an upright position. The study is based on the application of the principle of dynamic retention of the reverse pendulum on an oscillating suspension. The development of a new gripping and shearing device has been implemented, characterized by the presence of a vibration mechanism necessary to create vertical vibrations of the held tree. The article describes the design of a hinged gripping and shearing device with a vibration drive and the sequence of its operation when cutting, holding and packing wood. Dynamic studies of the vibration mechanism, taking into account the moment of inertia of moving elements in the SolidWorks Motion program, were carried out on a 3D model of the proposed design of the gripping and shearing device. As part of the motion analysis, the trajectory of the suspension point of the gripper-shearing device was constructed, having the shape of an arc with a maximum deviation of 5 cm. The analysis of the linear displacement of the suspension points of the ZSU showed that the vertical displacement is 500 mm, and the horizontal deviation is 50 mm. Studies of the movement of the elements of the proposed vibration drive design have shown that at a rotational speed of 150 rpm, a torque equal to 435 Nm occurs on the propeller shaft, which fits into the nominal torque of most high-torque hydraulic motors.

The article develops the dynamic loading of the power plant of a feller buncher machine in the process of pulling it up with the handle of a manipulator when harvesting wood on slopes. A mathematical model has been developed that allows, at the design stage of a compact feller buncher machine, to determine the magnitude of a significant dynamic moment existing on the machine’s power plant, as well as the crankshaft rotation speed. The mathematical description is in the form of the Lagrange equation of the second kind. An example of calculating a mathematical model for a LP-19A feller buncher machine is given. A graph of changes in the additional dynamic moment is presented at a pull-up speed of 0.1, 0.2 and 0.3 s^–1, as well as depending on the slope angle (15, 30 and 45°). A graph of changes in the dynamic coefficient depending on the value of the additional dynamic moment is presented. Graphs of changes in the reduction in the number of crankshaft revolutions are presented depending on the load on the power plant and depending on the slope angle. Analysis of the research results showed that pulling up the feller buncher machine with the handle of a manipulator when harvesting wood on slopes is accompanied by a significant amount of additional dynamic moment on the power plant, leading to a decrease in the crankshaft rotation speed. Thus, when pulling up the feller buncher machine on a slope with an angle γ = 15º, the maximum value of the additional dynamic load on the power plant will be 74.2 Nm, and the reduction in the crankshaft speed will occur at 311 rpm.

Increasing the efficiency of training for students of higher and secondary specialized educational institutions, enterprise personnel, including safe work practices, is currently an urgent task, since the effectiveness of traditional teaching methods is quite low. The purpose of the work is to analyze the directions of use of modern digital technologies in the field of training specialists in the forestry complex. The use of multimedia technologies and electronic courses makes it possible to revive the learning process, and the use of various simulators and augmented and virtual reality technologies can significantly increase interest in learning.

The investigated technology of modifying wood with a polymer compound with a carbon filler makes it possible to improve the quality of products and increase the strength properties of wooden structures. For wood modification, a polymer composition was used, including a resin – dimethacrylic polyester, a hardener – methyl ethyl ketone peroxide, an accelerator – cobalt octoate, a nanostructural additive – nanotubes «Taunit- M», a surfactant. The technology of modifying wooden structures consists in pumping a polymer composition with a carbon filler under excessive pressure of pulsed action. The mode of modification of wood by polymer composition (10-5-10-5-10 min) has been experimentally established: for 10 minutes, the sample was injected with a polymer compound, then the sample «rested» for 5 minutes, then the injection of the polymer composition was repeated for 10 minutes. To carry out work on the modification of the turbine, a mobile installation was used, including a container, a compressor, a trolley, an electronic control unit, a pressure sensor, a reinforced hose, and connectors. The vacuum rotary pump for wood modification is designed to create and maintain residual pressure during wood modification by the overpressure method. A scheme of zonation and topography of holes for injection of polymer composition was proposed and justified. Based on the ability to absorb wood of the polymer composition, the pitch of the injectors was experimentally determined 200 mm. According to the results of microscopy, a systematic introduction of the polymer composition into the wood structure was established, while the density of the modified wood increased by 34%. To assess the strength properties of the modified wood, compression tests were performed on standard samples selected from the structure. The test results showed an increase in the tensile strength of modified wood compared to conventional wood by 39.69% and a decrease in deformability by 7.7%.

Birch is one of the most common hardwood trees in Russia. In addition to relatively high physical and mechanical properties, birch wood has a number of disadvantages. Wood modification and active compounds to be used to impregnate birch wood can neutralise such negative properties. According to available information, these impregnation compounds are not always uniformly localised along the width of an annual ring when wood is impregnated. To identify the causes of nonuniform localisation, we studied the anatomical structure of birch wood along the width of the annual ring. To do so, samples of 20×20×100 mm (the latter along the fibres) were impregnated with an acid dye in an autoclave. After impregnation, the samples were kept for 24 hours under normal conditions to redistribute the dye. After that, wood sections of 20×20×20 mm were cut out of the central part of the dyed samples. Based on the resulted samples nonuniformly dyed along the width of the annual ring, we used our standard method to make transverse wood microcuts, on which the distribution of the dye was studied using a microscope and a digital camera. To study the structural anatomical characteristics of birch wood elements localised in different parts along the width of the annual ring, the wood tissue taken from the «early» and «late» zones of the ring was macerated. The microstructure of the wood fibres obtained from various parts of the annual ring was studied in transmitted light using a microscope and a digital camera. In the course of microscopic studies, the ScopyFoto software product was used to measure anatomical parameters, such as length, cavity diameter, cell wall thickness, pore number and size. The data obtained were processed using Microsoft Excel and Statgraphics. As a result of the studies, it was established that fibrous tracheids located in the «late» zone of the annual layer, in comparison with tracheids of the «early» zone, have 26% larger cell cavities, 47% thicker cell walls, 11.1% more width of bordered pores, as well as 17% more number of pores. But as for their height, the fibre tracheid pores of the «early» zone exceed those of the «late» zone by almost 27.5%. The fibre tracheids of the «early» and «late» zones of the annual ring have no significant differences in the length. Based on the obtained data, one of the reasons for the uneven coloring of the annual birch wood layer across the width seems to be the difference in the filtration parameters of the impregnation solution due to the difference in the pore width of fibrous tracheids in the «early» and «late» zone of the annual layer.

Ion-selective electrode membranes made from chalcogenide glassy semiconductors have valuable analytical and practical characteristics, such as a low detection limit of metal cations in aqueous solutions, reproducibility of electrode function, short response time of the analytical signal, miniaturization of sensors, and the ability to automate measurements. CdI₂-PbI₂-As₂Se₃ glasses were synthesized using the reagents cadmium iodide, chemically pure lead iodide, and special purity arsenic triselenide. Glasses were synthesized at a maximum temperature of 1000 °C in evacuated quartz ampoules with a residual pressure of 10^–4 Pa. When the temperature reached 1000 °C, the ampoules with the charge melt were kept for 4– 6 hours with constant stirring, then the melt was quenched in water with ice. CdI₂- PbI₂-As₂Se₃ films were deposited from solutions of glasses in n-butylamine. For the first time, potentiometric chemical sensors based on CdI₂-PbI₂-As₂Se3 chalcogenide membranes containing metal iodides have been obtained for direct determination of the molar concentration of cadmium cations in aqueous solutions. It has been established that the electrode properties of the resulting film and glass Cd-ISEs depend mainly on the content of cadmium iodide in the membranes, and the ratio of components in the chalcogenide matrix (lead iodide and arsenic selenide) affects mainly the electrode functions of the sensors. The parameters and dependence of electrical conductivity on temperature, as well as electrode properties in the CdI₂- PbI₂-As₂Se3 system are determined by the composition of the amorphous material and do not depend on the production method (glass or chemically deposited film from a glass solution).

The paper considers the application of a modern physical method for studying Fourier IR (infrared) spectroscopy in order to establish the dependence of parameters by deconvolution of the absorptive capacity of natural hardwood: hydrogen bond density, H-bond energy, hydrogen bond length for three types of H-bonds characteristic of cellulose-containing vegetable wood raw material. Features of intermolecular interaction in wood of various species and seasons of the year in comparison with technical cellulose have an additional characteristic of the Fourier IR spectroscopy method for an effective mechanism for predicting the physical and mechanical properties of wood pulp-containing materials, for assessing the nature of chemical bonds in the structure of wood materials, mechanical strength. The purpose of the pulp and paper mill is to produce high-quality industrial pulp. To achieve this goal, a comparison was made of the deconvolution performance of a modern method for studying FTIR-spectroscopy of hydrogen bonds of hydroxyl groups OH, including the influence of methyl-methylene CH stretching vibrations. One of the indicators used in comparing methods is the regression coefficient R^, which is a measure of the accuracy of the results obtained. In this study, the regression coefficient value for the samples is 0.999, which indicates a very high degree of reliability of the data obtained.

The influence of the main technological factors – the grinding step, the composition of the fiber mass and the type of drying is investigated. It was found that, with an increase in SP, the density decreases, in the range of 0.64–0.55 g/cm³, and the mechanical strength increases in the range of 235–275 (Coniferous cellulose) and in the range of 168–250 N (Deciduous cellulose). The absorbency varies slightly, in the range of 0.2–0.5 g / g, and has little effect on this indicator. Various types of fiber (softwood and lithic cellulose, BHTMM) are effective factors for quality management of cellulose composite and fluffed products. All the cellulose composites studied meet the criterion of water absorbency in the range of 11–13 g/g. Considering the absorbency of individual products, we note a different amount of absorbency, the limits of 17.4–20.7 g/g. The difference is about 3 g/g of water. In relation to the requirement, 11–13 g/g is about 25%, a significant amount. It is recommended to use a chemical and thermomechanical mass in the composition – no more than 25%, and according to the results of the study, 50% of coniferous cellulose and 50% of deciduous cellulose with a certain degree of grinding can be considered promising fiber compositions. Evaluating the effect of contact and convective drying, it was found that convective drying is much more effective, since samples dried by this method significantly exceed vacuum contact drying in consumer properties. Changes in the interrelated parameters «thickness» and «density» increase the water absorbency from 2.90 g/g to 5.5 g/g (by 90%).

A widely used first stuff for fluting and linerboard is neutral-sulfite semichemical obtained from hardwood. The paper studies the effect of high temperature on the strength properties of neutral sulfite semichemical board, and the morphological characteristics of the fibers in the board during its multicycle use in the process of corrugated production. It is shown that as a result of thermal influence on cardboard after 3 cycles of processing the fraction with shorter fibers (0,4–0,8 mm) becomes dominant, its increase was 13%, instead of fraction with fibers 0,8–1,2 mm, decrease of which was 7,6%. It was found that as a result of six cycles of processing at high temperatures simulating the corrugation process, the strength properties of paperboard made of neutral-sulfite semichemical decreased to a lesser extent than those of paperboard made of unbleached softwood sulfate pulp. This suggests that the lignin-carbohydrate complex of neutral sulfite semi-cellulose prevents intensive thermal destruction of cellulose. Therefore, the thermoplastic properties of lignin can be used without the danger of severe degradation of cellulose fibers and reduction of strength properties of cardboard, which will increase the number of cardboard processing cycles. In general, neutral sulfite semichemical pulp has a higher potential for recycling in corrugated production than unbleached sulfate softwood pulp of normal yield.

In the classic black liquor processing method for kraft pulp production, the mineral residue after burning the organic component of the black liquor in the recovery boiler is a mixture of sodium carbonate and sodium sulfate. The resulting soda solution is treated with lime coming from the decarbonization shop and a caustic alkali solution is obtained, which is subsequently used for pulping pulp in white liquor. As a result of the experiments, it becomes possible to improve the environmental safety of the black liquor processing process and diversify the production of sulfate cellulose, as well as simplify the hardware and technological scheme of the alkali regeneration process. The developed method is based on the distribution of potassium alkali between the solution and solid sodium sulfate by converting sodium sulfate with a KOH solution, depending on the change in the molar fraction of potassium alkali from the sum of potassium and sodium alkalis in the solution. Based on the considered patterns of distribution of potassium alkali between the sodium-potassium solution and sodium sulfate, a conversion method of potassium sulfate and sodium sulfate is proposed. The essence of the method lies in the exchange reaction between sodium sulfate contained in a solid mixture of sulfates with a potassium alkali solution. The work determined the optimal technological parameters for the separation of potassium sulfate from sulfate solutions and investigated the influence of individual technological parameters on the yield of potassium sulfate in the sediment. To set up the experiment, a rotatable central compositional plan was chosen. Evaluation of the research results makes it possible to come to the conclusion that the yield of potassium sulfate is affected not only by variable parameters, but also by their combination. Similar yields of potassium sulfate can be obtained with a reaction time of 60 minutes, but with different variations in the parameters. For the practical application of the presented scheme, the following optimal parameters were chosen: – the molar fraction of potassium alkali from the sum of potassium and sodium alkalis in the suspension – 60%, the mass ratio of liquid/solid in the suspension – 4.7, reaction duration – 60 minutes. Experimental data on the parameters for producing potassium sulfate as a fertilizer are scientifically substantiated. At the same time, it is proposed to obtain an additional commercial product when processing black liquor from sulfate pulp production.