The composite powder containing Al3Ni and Al3Ni2 intermetallic compounds was obtained by vacuum synthesis to reinforce the aluminum matrix of the developed composite. For this purpose, nickel and aluminum powders were mixed in a ball mill, followed by heating the resulting mixture in vacuum to 650 °C to initiate an exothermic reaction between the powder components. To obtain an Al–Al3Ni composite, the synthesized composite powder and matrix aluminum powder were mixed in a mill, followed by compacting the resulting mixture and sintering the obtained samples in vacuum. It has been found that vacuum synthesis results in the formation of a composite powder with heterogeneous phase composition, including Al3Ni, Al3Ni2, Al4C3, and Al. Carbon formed as a result of thermal decomposition of stearin on the surface of aluminum particles reacts with aluminum to form aluminum carbide. After sintering the compacted mixture of aluminum and composite powders, a composite reinforced with Al3Ni and Al4C3 phases is formed. Tribological tests have shown that the obtained composite is a promising wear-resistant material with hybrid reinforcement by intermetallic and carbide phases.

Results of generation of various suboxide layers on various thin oxidized niobium films by modification and sputtering of their surfaces with low-current argon ion beams are reported. Niobium films of various thicknesses were grown by magnetron sputtering on oxidized silicon substrates. Few stages of delicate ion bombardment were performed. The surface of films was studied by means of non-destructive methods of X-ray photoelectron spectroscopy and angle-resolved X-ray photoelectron spectroscopy. Chemical and phase film profiling was performed. It was found that during air exposure of niobium films of various thicknesses, layers of pentoxide and various stoichiometric and non-stoichiometric oxides had been generated. During ion bombardment, composition and thicknesses of the films did not change. Numerical modelling results showed that by delicate ion bombardment atoms of oxygen were mostly sputtered. It was the surface pentoxide niobium layer that was sputtered and modified. It was found that different layers of stoichiometric suboxides and pentoxides of other phases different from the initial phases had been formed. The composition of surface suboxide layers changed slightly. The results of this research show opportunity of generation of suboxide layers of various composition and thicknesses by changing parameters of ion irradiation of metal film surface.

The survey was performed to reveal the effects of draining agricultural landscapes on soddy-podzolic soil properties under cultivating oats (Avena sativa L.) in grass-cereal phytocenoses in order to record the variations in parameters for soils across certain agricultural landscapes. A stationary field experiment was conducted across the terminal moraine hill in the Tver oblast. The experiment was designed relative to the aspect of agricultural microlandscapes (factor A) including south slope transitional-accumulative landscape (T-As), south slope transitional landscape (Ts), south slope eluvial-transitional landscape (E-Ts), (hilltop) eluvial-accumulative (E-A), north-slope eluvial-transitional landscape (E-Tn), north-slope transitional landscape (Tn), and north-slope transitional-accumulative landscape (T-An) variants and the aspect of years of research (factor B) including 2020, 2021, and 2022. The maximum moisture content in the arable soil layer (72.1

The studies were conducted to assess the suitability of abandoned lands of a particular farm for growing barley by pure and cover cropping methods based on the analysis of the long-term monitoring data on its yield at an agro-ecological testing site. The study considered the long-term (1997–2012) monitoring data on the yield of barley variety Gonor in pure and cover (allowing for additional production) cropping at the Gubino agricultural site of the All-Russia Research Institute of Meliorated Lands. The agricultural site is located 4 km east of the city of Tver, on a hill with a prominence of 15 m, consisting of a flat top, a north facing gentle slope of gradient of 2°–3°, a south facing slope (3°–5°), and inter-hill depressions (northern and southern). Formation patterns of barley yield were identified using statistical and mathematical modeling. Based on the obtained formulas and archival data on a state of the abandoned lands, predictive crop yield surfaces were calculated for the entire territory of the farm. Pure barley crop responds only to the location elevation, while the yield of cover cropping depends on the elevation and gradient of the surface as well as phosphorus content of the soil. A quarter of the farm’s area (the upper hills in the west and south) is potentially capable of providing barley yields in pure crops from 1.4 to 3.3 t/ha; an increased yield (1.1–3.4 t/ha) can be produced by cover cropping on only 20

To produce highly porous ceramics with total porosity of 78-80 %, hollow corundum microspheres (HCMs) with the following characteristics were used: diameter - 140-180 mu m, wall thickness - 2-9 mu m, bulk density - 0.7 g/cm(3). These HCMs were obtained by plasma spheroidization (manufacturer: LLC << Kit-Stroy >>, St. Petersburg). Liquid glass (Na2O& sdot;SiO2& sdot;H2O) was used as a hardening binder for molding green bodies. Previously, aluminum powder consisting of flake particles was introduced into the volume of liquid glass. Such particles created a reinforcing framework within the structure of green bodies. In this case, liquid glass and aluminum powder together performed the function of a sintering activator during the subsequent heat treatment of the samples in air. Reaction sintering at a temperature of 600 degrees C, solid-phase sintering with the manifestation of the "zonal compaction" effect at 1200 degrees C and liquid-phase sintering in the range of 1600-1850 degrees C were recorded. The evolution of the structure and phase composition of ceramics was studied depending on the sintering temperature in the selected temperature range from 600 degrees C to 1850 degrees C. Depending on the sintering temperature, the compressive strength of ceramics was 4.0-17.3 MPa. Discrete fracture of the samples during deformation was recorded. The developed highly porous ceramics can be used as high-temperature thermal insulation.

A new method of X-ray photoelectron spectra processing based on a target model with a stochastic surface layer is proposed. On the basis of this model, X-ray photoelectron spectra of multilayer multicomponent metallic targets with an inhomogeneous surface layer are obtained for various probing angles considering surface shading effects. A layer-by-layer phase profile of metallic samples is obtained using the advanced method of surface analysis based on angle-resolved X-ray photoelectron spectroscopy. The results are validated by atomic force microscopy.

The results of long-term monitoring of the spatial dynamics of soil acidification within the terminal moraine hill are presented. The studies were carried out in 1996-2020. on the agro-ecological transect (VNIIMZ, Tver region) - an array crossing the landscape positions of the hill, consisting of 10 fields with an individual history. The exchangeable acidity of soils was determined at 30 sampling points, regularly located in each field at 40 m from each other. We used pHKCl data for 1996 and 2020 and acidification indicators determined as the difference in the values of soil exchange acidity at the beginning and end of observations. Statistical processing consisted in revealing the influence of anthropogenic and natural factors on soil acidification. It was found that the soils were significantly acidified during extensive farming. In 1996-2020 the average exchangeable acidity decreased by 0.6 (0.023 per year), but the soils did not move out of the slightly acidic category, which will take another 10 years. The spatial variability of pH significantly decreased: strongly acidic and neutral soils disappeared from the soil cover. It has been established that the landscape determines 34% of the spatial variability of soil acidification, and anthropogenic factors determine 26%. There are 4 groups of territories in the agrolandscape, significantly differing in the degree of soil acidification, which is explained by the heterogeneity of the relief and parent rocks. According to the diversity of anthropogenic impact, 5 groups of fields are distinguished, where differences in soil acidification are due to their history. In general, it is impossible to single out an anthropogenic factor in the agrolandscape that significantly affects the degree of soil acidification, however, the impact is noticeable on individual substowlands, which allows developing measures to reduce the intensity of this degradation factor. It is recommended to develop crop rotations within the tops of the hills and not to place fallows, hayfields and hatching fields with eastern goat's rue. On the middle, lower parts of the slopes and in inter-hill depressions, it is not recommended to place winter and cover crops.

The paper presents the results of predicting the yield of oats in the conditions of abandoned lands of the former pilot production farm (PPF) of the All-Russian Research Institute of Reclaimed Lands, located in the center of the Tver region. There were used the data of long-term monitoring (1997-2020) of the yield of this crop in clean and cover crops (with under-sowing of grasses) on the agroecological transect of the Gubino agroecopolygon located within the PPF. With the help of statistical and mathematical modeling, regularities in the formation of oat yields within the transect were revealed. On the basis of these formulas, predicted oat yields were calculated for the entire territory of abandoned lands, and maps of its variability under the conditions of the protected area and measures for intensifying grain production were also created. It has been established that oats in pure crops react most strongly to the content of exchangeable potassium in soils, to water supply and humus content, while in cover crops the yield largely depends on mobile phosphorus in the soil and the degree of illumination and swampiness of the territory. More than 92 % of the PPF area is potentially capable of providing oat yield in clean crops from 2.7 to 3.1 centners/ha, and an increased oat yield (3.0-3.3 centners/ha) in cover crops can be obtained only on ≈ 44 % of the farm area. The main methods for increasing the yield of oats in pure crops are the application of potash and organic fertilizers, as well as the preservation of moisture in the soil, while expanding the area of cover crops involves the use of oat varieties that react poorly to excess phosphorus in the soil. Intensification of oat production in clean crops is possible on the area of 6026 ha, and in cover crops only 790 ha, since in the rest of the territory its productivity is limited by insufficient illumination and waterlogged soils.

This paper examines the root density dynamics in gramineous–leguminous grass stands in various landscape conditions at different agrocoenosis development stages. Field studies were conducted in Tver oblast on an agroecological transect: a field that intersects the main landscape positions of a finite moraine hill. One hundred twenty sampling points were established on the transect 10 m from each other. The density of roots was measured in 2019–2021 under grasses at the first to third year of life. Effects exercised by environmental landscape factors on the root density were determined using various statistical analysis techniques. The studied parameter depends on both internal (biogeocoenotic) and external (landscape) factors. Internal factors result in a fivefold increase in root density in the period from the first to the first year of life. As the grass stand gets older, the root development intensity goes down. In the first year of life, root development is determined by the state of legumes, soil fertility elements, and terrain altitude; that in the second year is by interspecific competition in the agrocoenosis, granulometric and mineralogical composition of soils, and locality altitude; and that in the third year is by specifics of the soil pore space. Microlandscape conditions determine 21.5

The ceramic material was produced by sintering green bodies made of thin-walled hollow corundum microspheres (HCMs) obtained by plasma spheroidization. Highly concentrated aqueous solutions of metal chlorides (AlCl3 center dot 3H(2)O and a mixture of ZrOCl2 center dot 8H(2)O with YCl3 center dot 6H(2)O), hardened upon drying, were used as a binder for molding green bodies. As a result of the thermal decomposition of these metal chlorides in air, oxides Al2O3 and ZrO2-Y2O3, sintering activators, were formed within the areas between HCMs. Solid-phase sintering occurred due to the formation of Al2O3 within these areas, while the formation of ZrO2 - Y2O3 within these areas provided liquid-phase sintering as a result of the appearance of a eutectic melt in the Al2O3 - ZrO2 - Y(2)O3 system. In the first case, sintering took place at the points of contact between HCMs (compressive strength of ceramics is 0.4 - 1 MPa, density - 0,85 g /cm(3), total porosity - 80%), and in the second case, "necks" were formed between the HCMs, significantly strengthening the structure of ceramics (compressive strength of ceramics - 15 MPa, density 1,4 g /cm(3), total porosity - 65%).

Relevance . The problem of the influence of land use methods on the loss of potassium by soils, one of the main elements in the triad of plant nutrition, is considered. Methods . The studies were carried out in 1996–2020 on the basis of monitoring the potassium content in the soils of the Gubino VNIIMZ agro-polygon located within the limits of a finite moraine hill. The monitoring was carried out on an agro-ecological transect — an industrial array that crosses the main landscape positions of the hill and consists of 10 parallel fields, each of which has an individual history. Potassium was determined in each field at 30 sampling points located 40 m apart, which made it possible to assess the impact of natural and anthropogenic conditions on it. Correlation coefficients and regression models of the dependence of potassium losses on the totality of anthropogenic factors in various microlandscapes were calculated. Results . It is established that the nature of potassium migration depends on time, the characteristics of the natural conditions of the field and the history of its use. In the mode of extensive cultivation of crops, its content in soils is significantly reduced. Within the agricultural landscape, the spatial dynamics of losses is influenced by the diversity of natural conditions, while the nature of the history of fields affects migration flows only in certain parts of it. The features of the agricultural landscape that intensify potassium losses are a light granulometric composition and the dominance of eluvial processes. In transit and accumulative geocomplexes, potassium losses are lower. Based on the regularities obtained, it is possible to develop measures for the adaptive placement of land and crops, which makes it possible to minimize the loss of potassium.

The research aimed to assess the suitability of useless lands of a particular farm for growing barley in pure and cover crops based on the analysis of data from long-term monitoring of its yield at an agro-ecological test site. The work used data from long-term (1997-2012) monitoring of the yield of barley variety Gonor in pure and cover (allowing for additional production) crops at the Gubino agricultural site of All- Russian Research Institute of Reclaimed Lands. The agricultural site is located 4 km east of the city of Tver, on a hill with a relative height of 15 m, consisting of a flat top, a northern gentle slope with a steepness of 2-3о, a southern slope (3-5 о) and interhill depressions (northern and southern). Using statistical and mathematical modelling, patterns of barley yield formation were identified. Based on the obtained formulas and archival data on the state of useless lands, forecast crop yield surfaces were calculated for the entire territory of the farm. Barley in pure crops responds only to the height of the location, while in cover crops its yield depends on the height and steepness of the surface, as well as the phosphorus content of the soil. A quarter of the farm's area (the upper parts of the hills in the west and south) is potentially capable of providing barley yields in pure crops from 1.4 to 3.3 t/ha, and an increased yield of this crop in cover crops (1.1-3.4 t/ha) can be obtained only on 20 % of the territory occupying the transition zones between moraine and valley landscapes. Using only archival data is not always justified - different approaches to the design of farming systems must complement each other, and to clarify the yield forecast, it is necessary to conduct special landscape and soil studies.

Steel aluminum composite materials are widely used in engineering owing to excellent weight efficiency in combination with good mechanical properties. They are used, for instance, in the aerospace industry for production of rocket body structures, fuel tanks, and aircraft armor elements. This work is devoted to analysis of the crack resistance and the mechanism of destruction of aluminum-steel (20 vol %) composite material with the density of 2.85 g/cm3. The composite material was produced using very fine PAP-2 aluminum powder for formation of its matrix component. The reinforcing component was made of steel mesh woven from austenitic steel rope (08Kh17N13M2). The strength of the produced material upon transverse bending (550–600 MPa) was calculated by the maximum load corresponding to the first step of crack originating in the matrix. Its crack resistance at the stage of fracture initiation estimated by the parameter K1c was from 15 to 30 MPa m1/2. The crack resistance of the composite material at the stage of development of fracture was described by means of specific effective fracture work YF = 2 × 104—8 × 104 J/m2. For this composite material YF is an order of magnitude higher than for St3 steel, D16T aluminum alloy, and VT-5 titanium alloy, which is an advantage of the developed material. The high value of parameter YF is attributed to the mechanism of energy intensive destruction. It is provided by the increased energy consumption for the destruction of the bridges between the matrix aluminum layers by their shearing by the rope as a result of the action of shear stresses, for overriding of friction forces of rope drawing from the matrix, and for shearing of laminated packets inside the matrix formed by diffusion bonded scaly particles. The properties of the produced steel-aluminum composite material allow its use as a material for light structural elements operated under conditions of mechanical loading.

Relevance. The article is devoted to the topical problem of studying the influence of soil conditions and the relief of an agricultural landscape on the yield of clover-timothy herbage on drained soils, knowledge of which makes it possible to optimize the production process of crops in the mode of adaptive landscape farming.Methods and results. The studies were carried out in 1998–2020 at the test site of the All-Russian Research Institute of Reclaimed Lands (VNIIMZ) – a branch of the Federal Research Centre Soil Science Institute named after V.V. Dokuchaev (Tver region), located within the end-moraine hill. The purpose of the research is to study the influence of soil conditions and the relief of the agricultural landscape on the yield of clover-timothy herbage of 1 year of use. Grass productivity monitoring was carried out on a transect – a field crossing the main microlandscape positions (relief elements) and elementary soil combinations of the agrolandscape. Crop productivity and other parameters of the vegetation and soil cover on the transect were taken into account on 30 systematically located plots, within which there are 4 replicates, 23 m2 in area, spaced 10 m from each other.Results of studies on productivity were processed by correlation and multivariate analysis of variance. Studies have shown that the relief and soil features of the agricultural landscape have almost the same effect on the crop yield. Each of these factors, on average, determined 18–16% of the spatial variability in productivity. About 2/3 of the variability in the yield of herbs depends on factors that are difficult to take into account. It was found that the degree of influence of the relief and soils on the yield of grasses is not constant over time and ranges from 2 to 33%. In the time series of observations, periods of synchronous and asynchronous fluctuations in the degrees of influence of soil and relief on the yield were distinguished. Synchronization of temporal fluctuations in the degrees of impact on the productivity of grasses of different elements of the landscape occurs with a decrease in the amount of precipitation and active temperatures. On the basis of the revealed patterns, it is possible to develop measures to adapt technologies for growing perennial grasses to the natural conditions of farms in the mode of adaptive landscape fodder production.

A technique of controlled formation of multilayer oxide and suboxide layers on a thin metal film. An opportunity of controlled generation of films containing an ultra-thin suboxide layer inside a higher oxide layer and films being a periodic layered structure with alternating oxide layers of various oxidation levels. A structure containing alternating ultra-thin layers of higher oxide and suboxide layers on a niobium film. Keywords: metal-oxide films, controlled film formation, layer chemical and phase profiling, X-ray photoelectron spectroscopy.

Within the framework of the concept used, it is assumed that the destruction of ceramics due to thermal shock is initiated from defects in its structure, i.e., stress concentrators. In this case, the heat resistance of ceramics can be determined using the Weibull theory. For this purpose, a statistically significant sample of alumina ceramic samples was subjected to thermal shock. After that, the sample was mechanically tested and the Weibull parameters of the material were calculated (threshold stress, below which the probability of failure is zero; average strength value; limiting stress, above which the probability of failure is 100%; Weibull modulus). The degree of change of these parameters, in comparison with their values for sampling specimens before the thermal shock, served as an indicator of the thermal shock resistance. This indicator can be considered as a characteristic that determines the resistance of the ceramic structure to the initiation of thermal cracks on existing stress concentrators. The results of determining the thermal stability of alumina samples using the Weibull statistical theory were confirmed by the results of determining their thermal stability by the local thermal shock (LT) method.

Yield monitoring of a five-component grass stand in a breeding field within a moraine hill was carried out in 2003- 2018 in order to find patterns of its dynamics in the agrolandscape. The grass was used in the conditions of the Tver region without fertilizers in a single-cut mode in a field crossing all microlandscape positions of the hill (transcct) and divided into 30 plots. Annual data on productivity of grass mixture on each plot are presented in the form of: 1) absolute yield (specific hay yield); 2) relative yield (expressed as a percentage to maximum yield on a transect in a definite year). It was revealed that the yield of grasses is maximum in the central parts (≈ 6.5 t/ha) and minimal in the upper parts of the hillsides and at the top (≈ 5.2 t/ha). Time variability of yield depends on the geological structure of the soils ‒ increases with the transition from powerful binomials (≈ 40 %) to low-powerful ones (≈ 65 %). Correlation analysis showed that the transition to relative units (% of the yield) can significantly reduce the impact of climate on data variability. The maximum coincidence of temporal dynamics of different yield indicators is noted at the upper elevations ‒ here climatic conditions do not have a significant impact on the yield, as on slopes. Changes in the sum of the active temperatures have the greatest influence on the yield. Average indicators of correlation coefficients of yield and temperature sums are negative on the plots of soil distribution on powerful and medium-powerful binomials and positive on soils of low-powerful binomials. There has been found an inversely proportional dependence of the absolute yield of grasses on the sums of active temperatures in the pre-cut periods and in September and directly proportional in the second half of summer. Increasing the sum of temperatures contributes to a decrease in relative yields on sandy soils and optimizes the production process on loams and light loams. Dispersion analysis has shown that the main influence of temperatures on absolute yield is exerted by soil hydromorphism. The degree of impact of temperatures on relative yield depends on the nature of water exchange in the agrolandscape, the exposure of slopes (energy) and granulometric composition of soils. The results will make it possible to adapt measures for the placement of grass stands, regulation of water and thermal regimes of soils to farm conditions.

A technique of controlled formation of multilayer oxide and suboxide layers on a thin metal film. An opportunity of controlled generation of films containing an ultra-thin suboxide layer inside a higher oxide layer and films being a periodic layered structure with alternating oxide layers of various oxidation levels. A structure containing alternating ultra-thin layers of higher oxide and suboxide layers on a niobium film.

Aluminum-matrix dispersion-hardened composites are widely used in engineering owing to the combination of high strength characteristics and low density, which makes it possible to create lightweight and fracture-resistant structural elements for different purposes. They are used for the manufacture of abrasive, tribotechnical products; piston-block parts for internal combustion engines; airframes; and other special products. This work is aimed at studies concerning the fracture mechanism for layered dispersion-hardened Al–Al2O3–Al4C3 composites under the conditions of static and impact loading obtained using the liquid-phase vacuum sintering of PAP-2 powder billets. The liquid phase forms owing to Al–Al4C3 eutectic melt. The layered structure forms owing to the liquid-phase merging of flaky PAP-2 particles over the contacting planes. The dispersion hardening of the aluminum matrix is achieved thanks to precipitating nanoscale lamellar aluminum carbide crystals from the eutectic melt upon cooling. The synthesis of δ-Al2O3 alumina crystals occurs owing to the interaction between aluminum and residual air oxygen in the course of sintering in the furnace under vacuum at 10–5 mm Hg. It has been found that, under the conditions of static loading, the samples exhibit stable fractures according to a shear delamination mechanism accompanied by cavities appearing when layered blocks are torn out under the action of shear stresses (σbend = 430–500 MPa, K1c = 14.0–15.5 MPa m1/2). Under impact loading, a significant amount of material is involved in the fracture with the formation of cleavage steps between layered blocks and extended zones with ductile-fracture dimples. Due to this mechanism, a high level of KCU (1.1 × 105 J/m2) comparable to the VT-5L titanium alloy is achieved. The developed composite could be used for the manufacture of lightweight structural elements operating under the conditions of dynamic loading.

The cermet charge in the Al–Al2O3 system was obtained by mechanical processing (MP) of industrial grade PAP-2 (GOST 5494–95), consisting of flake particles of submicron thickness with a coating of stearin aluminum powder, in a planetary ball mill. Depending on the employed regimes of MP, 4 types of charge were obtained, the bulk density of which varied from 0.33 to 1.1 g/cm3. For all types of charge, the synthesis of the α-Al2O3 phase was observed as a result of the exothermic reaction of the interaction of air oxygen with the surface of aluminum particles during the MP. It is also possible to form boehmite and gibbsite when the activated surface of Al particles interacts with atmospheric water vapor. By energy-dispersive x-ray spectroscopy (EDX), x-ray amorphous carbon was detected in the composition of the charge, the appearance of which is associated with the impact- shearing effect of grinding bodies leading to the nucleation of x-ray amorphous carbon inclusions due to the thermal destruction of stearin. The maximum bending strength of the sintered cermet was 550 MPa. This cermet is characterized by a discrete fracture: the formation of dimples as a result of the shear of layered packets under the action of tangential stresses. The revealed mechanisms of fracture of cermet provide information to determine the optimal regimes of MP of powder compositions for obtaining various constructional elements from them.