Density Of Solid Phase Research Articles

Assessment of organic matter state and physical properties of postagrogenic sod-podzolic soil and its arable analogue

Land is often withdrawn from agriculture for various reasons, about 1/4 of the world’s fallow land is in Russia, mainly in the taiga forest zone. Some changes, determined by a combination of various factors, take place in fallow land. Therefore, in order to determine the expediency or priority of returning fallow land to arable land, it is relevant to assess the main indicators of its fertility. To this end, a comparative study of the organic matter and physical properties of an arable sod-podzolic soil and its post-agricultural analogue, which has been fallow for more than 20 years, was carried out. A reliable increase in the carbon content of the light fraction of organic matter in the 0-10 cm layer of the fallow soil was observed in comparison with the corresponding horizon of the arable analogue. In the 10-20 cm horizon this increase was manifested in the form of a tendency, also the tendency of increase in the content of organic carbon (total humus) in the former arable layer of the fallow soil was manifested. The increase in these indicators of the state of organic matter is apparently due to the increase in the amount of plant residues as a result of the succession of natural herbaceous vegetation compared to the amount of post-harvest residues on arable land. The fallow soil also showed an increase in the number of macroaggregates, agronomically valuable aggregates and the water holding capacity of macroand microaggregates compared to the arable soil. Obviously, such an improvement in the structural condition indicators is related to the increase in humus content and the absence of mechanical tillage, which favours the destruction of aggregates. The fallow soil in comparison with the arable soil had reliably lower density and density of solid phase, which is explained by higher content of light fraction of organic matter in it, as well as better structure. The obtained results allow to assess the nature of changes in fertility indicators of sod-podzolic soil as a result of staying in fallow condition. The indicator of the content of the light fraction of organic matter is an earlier indicator of the recovery of the fallow soil compared to the total carbon content in the soil, which allows to determine the expediency and priority of the return of fallow soils to arable land.

Комплексная оценка состава и свойств чернозема южного мицеллярно-карбонатного, орошаемого ограниченно пригодными водами

Purpose: to take a comprehensive assessment of southern micellar-carbonate chernozem content and properties, irrigated with limitedly available water. Materials and methods. The research was carried out on the territory of a pilot site located in the Saki region of the Republic of Crimea near the village Chervonoye. During the work, the state of water resources used for irrigation and the soil were analyzed. The assessment of water suitability for irrigation was carried out on the basis of soil reclamation classification. The analysis of soil conditions included the determination of: bulk density and solid phase density, granulometric content, particle size distribution, pH, expanded salt content of the. When determining the agro-physical properties of the soil water extract, the following methods were used: pycnometric, drying to constant weight, cutting ring, sieve with water washing, pipette. Results. The topsoil layer was identified as compacted with satisfactory porosity. The nutrient supply was mainly characterized as medium and high, only low content was recorded in 2022 for nitrate nitrogen (0.3–0.7 mg/100 g of soil). Despite the use of limitedly suitable water for irrigation, no water-soluble salt accumulation was recorded in a meter layer of soil. At the end of the irrigation period in 2023, the soils were classified as non-saline, and according to their granulometric texture depending on the depth – as medium loamy, heavy loamy and light clayey. Conclusions. Despite the fact that in the period from 2022 to 2023, irrigation with water with a mineralization of about 1.5 g/l did not lead to the accumulation of water-soluble salts in the soil of the pilot site, it is recommended to organize regular observations of its salt regime. This is justified by the fact that in drier years the precipitation may not be enough to wash out the salts arriving during the growing season with irrigation water into the underlying horizons.

Advanced Characterization of Pillared Graphene-Based Materials for Supercapacitors

Materials for supercapacitors have to display large surface area to maximize the number of adsorbed ions [1], and they must also possess a hierarchical porosity (Fig. 1) to favour ions diffusion. Graphene-derived materials are studied as they –theoretically- combine all these porosity-related parameters. However experimentally the achieved capacitance (CSP) remains limited because graphene sheets tend to re-aggregate. Our group has selected a method to avoid this issue by creating an expanded graphene structure by bridging and separating the sheets using aliphatic diamine pillars. These assemblies are called Pillared Graphene materials (PGM). Electrochemical results showed that these PGM display higher capacitance than reference non pillared materials [2,3]. However, it was not possible to correlate these storage performances improvements to adsorption active surface area determined with N2 gas sorption (BET), which questions the suitability of this technique for measuring the full porosity of the samples, which is likely to be more accessible in an electrolytic environment. Therefore, to further correlate storage performances of PGM to their structure, structural advanced characterization techniques such as small angle X-ray and neutron scattering (SAXS/SANS) were employed.These methods enable to assess samples porosity at the local scale (~30 to 140nm) as well as the solid phase density. In the frame of this presentation, SAXS/SANS not only have been applied to pristine materials, but also to specifically formulated samples (pellet, electrodes) in order to highlight structural differences arising from synthesis protocol or from molecular pillaring. The ionic charge diffusion and adsorption in specific porosity ranges, analyzed using preliminary Operando scattering techniques, will be evoked. So far the interplay between increased adsorption sites and improved electrochemical performances has only been intuited on the basis of indirect electrochemical studies; the strategy devised herein proposes the use of direct structural techniques to confirm these interpretations.

BOTTOM SEDIMENTS OF SURFACE WATERCOURSES OF THE MALMYZHSKY MOUNTAIN RANGE

X-ray fluorescence, electron microscopic, sedimentation analyses and laser diffractometry methods were used to study the composition of bottom sediments of surface watercourses of the Malmyzhskaya Ridge section allocated for the construction of a mining and processing plant (Khabarovsk region, Russia). It is established that the bottom sediments of the coastal zone of the watercourses of the studied area are characterized by a similar gross composition and physical and chemical properties (pH, solid phase density, total carbon content, wetting edge angle CAW). Th ey are mainly represented by fine earth with a high proportion of suspended sediments, in which the fraction of coarse silt prevails (particle size <2,0 mm, <0,1 mm and 0,01-0,05 mm, respectively). It is shown that deforestation in the sources of watercourses accompanied by soil erosion leads to a significant increase in the dispersion of sediments (an increase in the proportion of suspended sediments up to 90%) in the upstream. Downstream, with the distance from the felling sites, the infl uence of deforestation on the dispersion of deposits fades. Th e content of suspended sediment is reduced to values characteristic of watercourses in the catchment area of which deforestation has not been carried out. Significant microaggregation of suspended sediments of watercourses was revealed, the participation of microbiota (testate amoebas of xenosome taxa, diatoms and Fereducing bacteria) in the formation of microaggregates was diagnosed. Th e latter are involved in the formation of vivianite on the surface of ferruginous-clay microaggregates with an increased content of phosphates after fires. The mechanism of formation of toroidal microforms of vaterite in bottom sediments with the participation of cyanobacteria of the Spirulinaceae family is proposed.

ANALYSIS OF MORPHOLOGICAL STRUCTURE AND CHEMICAL COMPOSITION OF EDAPHOTOPES OF POST-TECHNOGENIC AREAS OF SULFUR QUARRIES

The results of the research of the peculiarities of morphological structure development and change in chemical indicators of edaphotopes of embriozems and technozems on the post-technogenic lands at the Yavoriv and Podorozhnie sulfur quarries were described in the article. During 30 years after intensive sulfur mining was stopped and mines closure under the influence of various environmental and human-caused factors significant changes of disturbed soils characteristics occured within the sulfur quarries. It was established that soil cover of post-technogenic areas was represented by special combinations of various types of embriozem soils (initial, organic and accumulative, humus and accumulative, and dernozem). The most widespread embriozem soils are organic and accumulative, which are developing at the organic substances accumulation stage in the surface layer. Embriozem and technozem soils of the Yavoriv quarry belong to the dense type of soil with soil density index of (d1) 0,96–1,57 g/cm3. Solid phase density (d2) is 2.21–2.60 g/cm3, which corresponds to low-humus mineral horizons with bare horizon and its values are close to the natural background of zonal soils of the disturbed landscapes. Based on the hydrogenous index pH (8.0–8.9) emrbiozem soils are alkaline; and technozem soils with pH7.6 are regarded as slightly alkaline.The level of values of indicator of hydrolytic acidity of soils on post-technogenic areas is high (0,185–0,615 mg-CaCO3/100 g), which is 2.6 times higher than in zonal soils. During almost 30 years period, as a result of natural processes humus content in embriozem soils increased up to 0.29–0.61%, in technozem soils – 0.83–1.47%. The content of mobile forms of nitrogen in edaphotopes of the Yavoriv and Podorozhnie sulfur quarries fluctuates from 18.9 to 112.3 mg/kg of soil and from 13.7 to 54.5 mg/kg of soil, respectively. During 2011–2021, the increased content and accumulation of main macroelements in embriozem and technozem soils of the both quarries were recorded.

Experimental determination of the solid phase density of thermal power plant ash

Recycling of ash and slag waste from thermal power plants is an important environmental and economic task. The widespread use of ash in construction is mainly hindered by the high content of unburned carbon. The fine granulometric composition of the ash makes most mechanical methods of recycling and flotation ineffective, and is the most effective, environmentally friendly, and cheapest method is hydraulic separation. It allows for the recovery of about 70% of construction raw materials, in which the carbon content is reduced to regulatory commercial values, from 20% in raw ash to 5–10%. A central element of hydraulic separation research is establishing the hydraulic characteristics of the fly ash, with a special focus on determining its actual density, considering that the ash includes more than 10 different mineral components that have also undergone high-temperature transformation. Theoretical determination of the solid phase density of a multi-component mixture does not yield a reliable result. This article examines methods for determining bulk, true, and actual density, experimental approaches to their measurement, and the impact of various factors on these parameters. Correct density determination underlies the calculation of hydraulic characteristics of ash suspensions, the speed of hydraulic flows, and the efficiency of extracting individual components by way of hydroclassification and hydroseparation. The purpose of the research is to refine the methodology and experimentally determine the density of the solid phase of fly ash in its natural state and ash classified by size -240+40 µm, -40+0 µm, using the sample of ash from Pridniprovska TPP. The results of this work are significant for engineering when creating new technologies, for hydraulic devices recycling ash aimed at minimizing environmental impact and optimizing the use of technogenic resources. It was found that the density of the solid phase of ash from the ash dump of Pridniprovska TPP varies from 1.783 g/cm³ to 2.3, averaging 2.0 g/cm³. Variations in density are related to the inhomogeneity of the chemical composition, the presence of closed cavities in the particles. Keywords: fly ash, ash and slag waste.

THE IMPACT OF REFORESTATION ON PHYSICAL AND HYDROPHYSICAL PROPERTIES OF SOILS OF THE FALLOW LANDS (SKOLIVSKI BESKYDY, THE UKRAINIAN CARPATHIANS)

The article tackles the impacts of anthropogenic load on the physical and hydrophysical soil properties. In order to better comprehend the processes of spontaneous sylvatisation in a mountain region (the Pohartsi boundary, Koziova village, the Skolivski Beskydy physiographic region) four study plots were selected representing the successional sequence: forest → pasture → hay meadow → arable lands. Land patches that were affected the least by anthropogenic load restored faster to their natural baseline conditions. Tilling appeared to retardate restoration processes, however those anyway took place. Proper functioning of arable land patches may be facilitated by continuous land care actions (i.e. ploughing or mowing).We found that soil bulking density in arable lands increased in upper soil horizons compared to forest ecosystems. Such an increase is caused by mechanical turning upper soil horizons up down and vice versa, for lower horizons. In pasture lands, upper soil horizons are trampled down by livestock. This leads to lower water permeability of soils: increase in soil bulk density from 0.79 to 1.15 g•cm-3 resulted in a decrease of water permeability by 75 %. In forested lands, values of water permeability similar to those in arable lands (0.55 mm•min⁻¹) are usually observed along the walking trails and in wood trilling plots. On the land patches with scarce herbaceous cover erosion processes are emerging. The latter is especially dangerous for arable land patches causing extra leak of soil nutrients and thus soil depletion. In order to further exploitation soils in such patches need additional fertilizing. As agricultural load diminishes soil upper horizons restore. Restoration occurs through prolonged freezing and thawing cycles during the cold (autumn-winter-spring) season. Another path for soil physical properties restoration is associated with penetration of plant fine roots that loosen the soil. Increase of total sparing indices is observed, as well. For upper horizons of restored soil it is assessed as “intermediate” (62,00 ‒ 65,35 %) whilst for arable land patches it is significantly lower (54,90 %). Soil bulk density gradually decreased along soil profiles and study plots. In forested patches it reached minimum (2,28 g•cm⁻³) and in arable land patches – maximum (2.55 g•cm⁻³) values, which did not change upon termination of anthropogenic load. Significant changes were observed for the field humidity indices. These varied both spatially, along soil profiles, and temporarily, by seasons. Lack of herbaceous vegetation caused over-drying in upper soil horizons. At the same time in lower horizons field humidity increased. Upper soil horizons in forested patches undergo the least changes due to the presence of thick forest floor. We conclude that major indicators of agricultural load within a soil profile are soil bulk density, water permeability and total sparing. Such indicators as the solid phase density and field humidity are of additional value. Key words: reforestation; soil bulk density; water permeability; soil profile; arable lands; pastures; Skolivski Beskydy.

A Macro-microscopic Coupled Constitutive Model for Fluid-Saturated Porous Media with Compressible Constituents

The paper provides a macro-microscopic coupled constitutive model for fluid-saturated porous media with respect to the compressibility of the solid skeleton, the real solid material and the fluid phase. The derivation of the model is carried out based on the porous media theory and is consistent with the second law of thermodynamics. In the present paper, two different sets of independent variables are introduced to implement the coupled behavior between the compressibility of the solid skeleton and the real solid material. Altogether the proposed model exploits five independent variables, i.e. the deviatoric part of the right Cauchy-Green deformation tensor, the partial density of solid phase, the density of the real solid material, the density of the real fluid material and the relative velocity of the fluid phase. Subsequently, the linearized version of the proposed constitutive model is also presented and compared with some models by other authors. It is found that Biot's model can also be derived based on the linearized version of the proposed model, which indicates that the present work bridges the gap between the porous media theory and Biot's model. Compared with Biot's model, the present model can provide the evolution of the porosity by considering the volumetric strain of the solid skeleton and the volumetric strain of the real solid material.

1D_RnDPM: A freely available 222Rn production, diffusion, and partition model to evaluate confounding factors in the radon-deficit technique

The radon-deficit technique is a powerful tool to detect and delineate sub-surface accumulations of organic contaminants. Field measurements of 222Rn in soil air, however, are affected by several confounding factors that can lead to the misinterpretation of results. Among the most influential are: vertical and lateral changes of lithology, fluctuating contaminant saturations with depth, varying water saturation ratios along the soil profile and atmospheric (and, therefore, soil) thermal oscillations. To evaluate and minimize the effect of these confounding factors on the interpretation of the results of the Rn deficit technique, a Matlab® based multi-layer model of 222Rn production-partition-diffusion in unsaturated porous media (1D_RnDPM: One-Dimensional 222Rn Diffusion and Partition Model) has been developed and is freely available as Supplementary Material in this work. A laboratory protocol has also been proposed to obtain site-specific input parameters for the model, i.e., 222Rn equilibrium concentration (as determined by the accumulation chamber method), soil bulk density and soil solid-phase density. The model predictions have been contrasted with field information obtained from successive sampling campaigns in which 222Rn in soil air was measured at a site where the vadose zone, consisting of an anthropogenic backfill underlain by a silt layer, is affected by a complex mixture of benzene, phenol, (poly) chlorobenzenes, (poly) chlorophenols and hexachlorocyclohexane isomers, among other compounds. The model has successfully predicted the vertical profile of 222Rn concentrations in soil air, including the effect of the oscillations of the water table and of ground-level temperature. The results also underline that 222Rn measurements in subsoil air are representative only of local conditions around the sampling point, an expected result given that 222Rn maximum effective diffusion length is very limited. As a consequence, the influence of a highly fluctuating water table at the site goes undetected at the sampling depths used in the field campaigns. Main findingsThe combination of a numerical model and a laboratory protocol allows to predict the activity of 222Rn along the soil profile and to assess the influence of site-specific confounding factors.

THE IMPACT OF RECREATION LOADING ON PHYSICAL AND WATER-PHYSICAL PROPERTIES OF BROWN FOREST SOILS

The article analyses the influence of recreational load on the physical and water-physical properties of brown forest soils. It is established that the complete or partial absence of litter on the pathway contributes to the rapid evaporation of moisture from the upper horizon (0−5 cm) of the soil, reducing the porosity total, increasing the density solid phase and buk density. It was found that with the increase of the buk density by 12,5 % the water permeability of the soil decreases 33 times in comparison with the control. A significant increase in the bulk density of the structure by 39−48 % was found on partway with a width of more than 2 m. On these pathway the surface runoff of water is formed. An increase in the density of the solid phase was recorded. The results of which are characteristic of the Hp horizon of brown forest soils. The overlapping of the trail with wooden flooring on the track “Stezhkamy lehendarnoyi Tustani” had a positive effect on the physical and water-physical properties of the soil. It was found that the indicators of soil bulk density and water permeability were close to the results obtained in the control and only the increase in the density of the solid phase indicates a significant recreational impact in the past. On the roadsides of the same revealed a significant increase in soil density of 1,5 times compared to the control and 1,3 times with the results obtained on the pathway, this indicates a recreational impact to date. It is proposed to use the following criteria for degradation of natural ecosystem: quantitative and qualitative changes in vegetation (meadow ecosystems), presence/absence of forest litter (forest ecosystems), soil density, presence of additional/parallel paths, path width, depth of erosion on the pathway. Establish category (stages) of recreational degression on the tracks the National Park “Skolivski Beskydy”. On the first stage/category (“Unchanged track”) of recreational degression includes trails 0,35−0,70 m wide with relatively close indicators of soil structure bulk density to control and the presence of forest litter on the pathway. The only negative aspect in this category is the insufficient water permeability of the soil. On heavy II category there is forest litter, although its redistribution is mainly traced between the trail and its roadside. In some sections of the trail, where there is no forest litter, it is fixed by increasing the bulk density of the structure to 27 %, the width of the pathway is 0,9−1,2 m and is classified as “Little-changed track”. On pathway with 2,15−3,40 m, there is a complete or partial absence of forest litter. Bulk density increased by 38−39 %, surface water runoff is formed. It is established presence distinct partway, visibled qualitative and quantitative changes in vegetation. The presented data correspond to the pathway of III category and are classified as “Endangered track”. Category IV (“Devastated track”) includes paths on which there is no forest litter, a significant increase in soil density up to 48 %, access to the surface of the root system and the width of the path is 2,60−4,90 m. Key words: recreation influence; soil bulk density; water permeable; pathway; NPP “Skolivski Beskydy”.

Изменение противоэрозионной стойкости орошаемых серо-коричневых почв сухой субтропической зоны Азербайджана в зависимости от давности их орошения

Изменение противоэрозионной стойкости орошаемых серо-коричневых почв сухой субтропической зоны Азербайджана в зависимости от давности их орошения

Application of a non-cubic equation of state to predict the solid-liquid-vapor phase coexistences of pure alkanes

A methodology to predict solid-liquid, solid-vapor, and liquid-vapor phase coexistences using a non-cubic equation of state is presented. The solid phase is additional to the liquid and vapor phases that can be worked with a cubic equation of state; thus, the triple point of the substance is represented. For a given substance, the seven parameters of this equation of state are obtained using the following data: the liquid-vapor critical point, acentric factor, boiling point temperature, and triple point temperature. The procedure to do this is described and is used to validate the methodology through obtaining the pure component parameters of this equation of state for 40 pure alkanes. As examples of the capacity of the reported non-cubic EoS to represent the coordinates of the three different phase transitions, predicted P-T and P-V phase transition diagrams are reported for methane, pentane and octane, and they are in good agreement with experimental data. This methodology is suitable to be used with any substance for which the density of solid phase is higher than that of liquid phase.

Effect of cavitational conditioning of water on stability of coal-water slurry

Coal-water slurry (CWS) is the basis of modern alternative fuel - coal-water fuel (CWF). To produce stable coal-water slurry, i.e. coagulation and separation is an important technological problem. The paper studies CWS the disperse part of which is fine brown Kansk-Achinsk coal, the dispersive part is distilled water. Effect of cavitational conditioning on CWS stability has been studied. The efficiency was for the first time studied by magnetic resonance tomography (MRT). In the experiment spin-lattice relaxation time profiles T1 were recorded along the central vertical axis of the samples. T1 dynamics correlates well with the local density of CWS solid phase. MRT data was sequentially interpreted with rheological characteristics of CWS. Feasibility of applying MRT method to find out time and space evolution of CWS has been estimated. The MRT methods has been shown to be efficient in resolution of technological problems to improve consumer properties of the coal-water fuel.

STUDY OF AGRO-PRODUCTIVE FEATURE FEATURES OF SOIL COVER OF GANJA-KAZAKH REGION OF AZERBAIJAN

In the article, the object of study of the Ganja-Gazakh steppe is widely distributed in the following areas: Mountain-forest brown soils washed from carbonates (Haplic Castanozems). Mountain-brown soils (Kastonozems) from the forest, washed from carbonates. Under the forest, carbonate mountain-brown soils (Kastonozems). Wild mountain-forest brown soils (Mollic Leptosols Eutric). Carbonate mountain-black soils (Chernozems, 1350 m). Dark mountain gray-brown soils (Castanozems). Ordinary mountain gray-brown soils (Castanozems). Light mountain gray-brown soils (Castanozems). Dark gray-brown soils (Haplic Castanozems Chromic). Common gray-brown soils (Haplic Castanozems Chromic). Dark gray-brown, Light gray-brown soils (Castanozems). Wetland-meadow soils (Gleysols). Field-soil-erosion researches were carried out, numerous sections were made in these soils and samples were taken from different genetic layers and laboratory analyzes were carried out, their granulometric composition, agro-chemical and water-physical properties were studied and studied. solid phase density, hygroscopic moisture, soil swelling ability, its compaction capacity, pH.In water suspension, the sum of absorbed bases, m.eq., the sum of absorbed bases, Na%, Carbonate content, total nitrogen and humus content were determined and their erosion limits were determined.

Nutritional value and productivity of perennial grasses used in animal feeding when creating cultural phytocenoses

The natural and technological properties of land and the conditions of the territory are determined by landforms, the contour of the fields and their fragmentation, and a number of other indicators related to the geographical conditions of the area. Their influence on agricultural activity and production is manifested directly through the features of the soil cover. Long-term studies carried out by employees of the Kursk Agricultural Academy have shown that the problem of restoring disturbed lands in the Kursk magnetic anomaly region can be successfully solved. One of the promising areas for the development of disturbed lands is the cultivation of perennial grasses directly on overburden. In the experiments, chalk, sands, soil mixtures, silts of the Jurassic, rocks of the Devonian system were used as a substrate for growing perennial herbs. In terms of chemical composition, these rocks are non-toxic and non-saline, at the same time they are poor in organic matter (0.1–0.4%) and mobile nutrients. The mechanical composition (except chalk) is light. Overburden rocks are characterized by increased bulk density (1.50-2.02 g/cm3 and solid phase density (2.70–2.86 g/m3). According to the four-membered classification of A M Burykin, the studied rocks are conditionally suitable and should be used for afforestation and tinning.

Atomistically informed melting models for aluminum nanocrystals

Atomistically informed analysis of melting is conducted to predict equilibrium melting points of aluminum nanocrystals in the size range 2–10 nm. Spherical and cubic nanocrystals and planar films are considered. Relevant properties are calculated using atomistic simulations and fed as inputs to thermodynamic models. Bulk melting point is calculated using solid-liquid coexistence simulations, while surface free energies are obtained using thermodynamic integration approach. Solid phase density and latent heat of melting are calculated using atomistic simulations of infinite bulk. Melting points are also computed using atomistic melting simulations. Care is taken to minimize superheating and detect onset of melting accurately. Qualitative agreement between predictions of atomistic simulations and thermodynamic models is achieved. Some interesting trends regarding size and orientation dependencies of melting points are reported. Studying radial variations of the potential energy is an effective and consistent way to detect the onset of melting for all particle sizes.

ОЦЕНКА ПЛОТНОСТИ ЧАСТИЦ ТВЕРДОЙ ФАЗЫ ПУЛЬПЫ С ИСПОЛЬЗОВАНИЕМ ИЗМЕРИТЕЛЬНЫХ КАНАЛОВ НА БАЗЕ ГАММА-ИЗЛУЧЕНИЯ И ВОЛН ЛЭМБА

Актуальность исследования обусловлена необходимостью повышения точности средств ультразвукового оперативного контроля характеристик твердой фазы железорудной пульпы в процессе обогащения. Данное направление совершенствования средств контроля позволит повысить эффективность управления процессом обогащения и качество конечной продукции. Цель: повышение точности измерений плотности частиц твердой фазы пульпы на основе закономерностей распространения гамма-излучения в случайно неоднородных гетерогенных средах, а также волн Лэмба по поверхностям, контактирующим с этими средами, в процессе их естественного и специально организованного перемещения. Объекты: процессы распространения гамма-излучения в случайно неоднородных гетерогенных средах, а также волн Лэмба по поверхностям, контактирующим с этими средами. Методы: систематизация и анализ разработанных методов ультразвукового контроля характеристик твердой фазы гетерогенных неоднородных сред, методы математической статистики и теории вероятностей для обработки результатов экспериментов, компьютерные информационные и программные технологии для реализации разработанных подходов. Результаты. Выявленные закономерности распространения гамма-излучения в случайно неоднородных гетерогенных средах, а также волн Лэмба по поверхностям, контактирующим с этими средами, в процессе их естественного и специально организованного перемещения позволяют определить плотность частиц твердой фазы, которая при известной их крупности и концентрации в контролируемом объеме характеризует степень раскрытия полезного компонента (минерала). Разработана схема устройства контроля плотности твердой фазы суспензий на основе полученных закономерностей. Погрешность измерений плотности частиц твёрдой фазы пульпы составляет 1–3 %.

Исследование водно-физических свойств орошаемых лугово-серых почв на опытном участке в условиях Азербайджана

Water-physical properties of the soil are not constant, they often are changed under the influence of natural conditions and agrotechnical measures. Studies show that water-physical properties directly affect the life and growth of plants. In this regard, the main tasks are to study the changes in water and physical properties of the soil under various crops in irrigated areas and to develop the systems of agromeliorative measures. As a result of researches the water-physical properties of irrigated meadow-gray soils of the experimental site at the Salyan plain were studied: physical clay – 48.2...56.79%, density of solid phase – 2.62...2.73 g/cm3, density of dry soil – 1.22...1.46 g/cm3, total moisture capacity – 31.86...43.80%, soil porosity – 46.52...53.44 %, CaCO3 –11.11...14.96%, pH – 8.2...8.6, SO4 in gypsum – 0.077...0.899%, the ratio of absorbed bases – 12.27...15.96 milligram equivalents. Researched soils have a weak and medium degree of water permeability (Kt = 5.51...8.83 cm/h the Kostyakov equation). The traditional and modern methods of irrigation (furrowing, sprinkling, drip, etc.), application of fertilizers (organic, mineral and micro fertilizers, local fertilizers, silt deposits of river waters, etc.) are recommend as agrotechnical measures in accordance with preliminary study of ratio of salts in soil.

Thermodynamic description of the plutonium – α-d-isosaccharinic acid system I: Solubility, complexation and redox behavior

The impact of α-d-isosaccharinic acid (HISA), a degradation product of cellulose, on the solubility and redox behavior of hydrous Pu(IV) oxide was investigated from undersaturation conditions under Ar atmosphere in 0.1 m NaCl–NaOH–NaISA solutions. Redox conditions were buffered with hydroquinone (HQ) or Sn(II), resulting in (pe + pHm) ≈ 9.0 and 1.5, respectively. The influence of ISA on Pu solubility was investigated as function of pHm (8 ≤ pHm ≤ 13) and ligand concentration (10−6 m ≤ m(ISA)tot ≤ 0.1 m).In-situ X-ray diffraction and X-ray absorption spectroscopic measurements indicate that PuO2(ncr,hyd) controls the solubility of Pu in all investigated systems. Presence of ISA poses an increase in plutonium solubility by up to 2.5 log-units. In HQ systems, slope analysis of solubility data in combination with solid phase characterization and density functional theory calculations resulted in chemical and thermodynamic models including the predominance of Pu(IV)(OH)3ISA–H– and Pu(IV)(OH)3ISA–2H2– complexes below and above pHm ≈ 12, respectively. In Sn(II) systems with pHm < 11.5, a reductive dissolution occurs involving the formation of Pu(III)(OH)ISA–H(aq). Experimental observations suggest also that Pu–ISA colloids importantly contribute to the overall Pu concentration in solution, both in HQ and Sn(II) systems. Although this process is not included in the thermodynamic model derived, it cannot be neglected for estimating Pu solubility limits under these conditions. This work provides the most comprehensive thermodynamic dataset available to date for the system Pu3+–Pu4+–OH––Cl––ISA––H2O(l) valid under a wide range of conditions relevant for nuclear waste disposal.

AUTOMATIC CONTROL SYSTEM PULP DENSITY IN THE AGITATOR DURING PREPARATION FOR FLOTATION

The paper provides a brief overview of researches on automation of flotation beneficiation. The main disadvantages of existing systems and methods for regulating parameters of this process have been revealed, which consist in low speed, errors in determining control action, and incapability of stabilizing pulp density in a mixer. In this connection, a conclusion is made about the relevance of development of an ACS for the process of pulp mixing before flotation, which will allow maintaining the specified density at a given level. Modeling using Matlab Simulink software package was chosen as the research method. At the same time, mathematical description of such elements of the ACS model as the valve, the mixer, the pump, the PID controller is given. The modeling provided time diagrams reflecting the principle of the pulp density stabilization by manipulating the flow of water into the mixer with abrupt change in the pulp solid phase density and flow. Conclusions are given on the possibility of using the ACS as part of an automated process control system at mining enterprises, since the system model operation showed satisfactory results in density control with small readjustment and low control time.