Russian Scientific Center "Applied Chemistry"

A comprehensive study of the effect of elastic anisotropy on hydraulic fracturing was conducted in tight sandstone reservoir of Field X. The main goal of the research was to identify the most effective hydraulic fracturing technology to enhance production and mitigate risks of increased water cut in tight reservoir. The reservoir comprises several hydro-dynamically isolated zones (tight sandstones; permeability is less than 0.3 mD). Sandstones are isolated by a highly laminated and anisotropic shale layer, which plays a major role in hydraulic fracture design. A lack of information about shale anisotropy may result in underestimation of stress barriers and subsequent errors in fracture geometry modeling. In order to understand the evolution of fracture growth and, as a consequence, define an appropriate fracturing technology, an anisotropy analysis was performed. The model of shale anisotropy was based on cross-dipole acoustic data and core measurements of elastic static and dynamic properties. To validate the geomechanical model and fracture geometry, a geophysical survey was performed before and after fracturing. A comprehensive well study included sonic logging data in the open hole before and after hydraulic stimulation, thermometry after mini-fracturing and after the main stage of hydraulic fracturing, pulsed neutron gamma ray imaging (NRT—non-radioactive proppant), and a complex study of VTI anisotropy. Based on measurements during the diagnostic fracture injection test (DFIT) and fracture calibration test (FCT), the minimum stress and fracture geometry were validated. Strong anisotropy in the shale layer leads to high minimum horizontal stress, and as a result, the fracture is placed in one zone and doesn’t propagate through the shale layer. The modeled fracture geometry is in good agreement with geophysical measurements of fracture height. In addition, changes in fracture width due to the influence of hoop stresses and reduction of bottomhole pressure was estimated. An aggressive reduction in bottomhole pressure has a negative effect on fracture width nearby the borehole. A model to estimate this effect was developed in this study.

The life cycle of the proposed ways of polymer materials recycling was assessed. Three scenarios for the recycling of polyolefins and rubber from used tyres are considered: the basic one – incineration, as well as traditional pyrolysis and slow pyrolysis under pressure. For each case an inventory analysis was performed: quantification of input/output streams, development of a material balance sheet and life cycle diagram. The environmental impact of technical solutions was analysed. It is concluded that incineration is unacceptable for both types of waste. It is found that the method of slow pressurised pyrolysis has the lowest risks of environmental impact.

Selective photoreduction of carbon dioxide (CO2) to methane (CH4) remains a major challenge, which involves a kinetically unfavorable transfer of eight protons and eight electrons. Herein, a photodeposition strategy was employed to deposit nano Cu metal on flower-like Nb2O5 microspheres (Cu/Nb2O5) for CO2 photoreduction to generate CH4 under simulated sunlight. The results show that the 1.0% Cu/Nb2O5 catalyst produces CH4 with an electron selectivity of 84.8% and a formation rate of 15.89 μmol g–1 h–1 without the use of sacrificial agents and photosensitizers. The generation of *CH3O on the 1.0% Cu/Nb2O5 catalyst during the CO2 photoreduction process was monitored using in situ Fourier transform infrared spectroscopy. Theoretical calculations further indicate the formation of highly stable C1 intermediates plays a crucial role in determining the reaction selectivity. By optimizing the electronic structure of the catalyst, this strategy provides a viable strategy for the photocatalytic conversion of CO2 and H2O into CH4 products, offering new insights into the development of efficient and sustainable CO2 conversion technologies. Moreover, it provides strong theoretical support and an experimental basis for the widespread application of photocatalytic CO2 reduction in greenhouse gas emission reduction and green energy production.

The paper analyzes the results of experiments on inelastic scattering of polarized protons on $${}^{54,56}$$ Fe nuclei. The work presents for the first time the differential cross sections and analyzing power for levels $$2_{1}^{+}$$ , $$2_{2}^{+}$$ , $$4_{1}^{+}$$ , $$4_{2}^{+}$$ for the scattering of protons with an energy of 16 MeV. The published data for the same levels, but for proton energies of 18.6 and 400 MeV are also analyzed. Calculations of inelastic scattering observables were performed using the coupled channel method for a proton energy of 16 and 18.6 MeV and the distorted wave method for a proton energy of 400 MeV. The predictions of two collective models of excited states of the nucleus were compared: the asymmetric rotor model and the multiphonon vibrational model. In addition, the wave functions of excited states calculated using the shell model were tested.

This paper presents a brief analysis of modern sources of knowledge for artificial intelligence (AI) applications and discusses prospects of their development. It is shown that methods, algorithms, and technologies for knowledge extraction based on machine learning, as well as various knowledge extraction techniques that use the digital twin (DT) technology, are currently quite mature and in great demand. As for expert knowledge, it is rarely used in practice, even though it is essential in a number of critical and often unique classes of next-gen applications for which experts are the only available source of knowledge. To solve the problem of efficient access to expert knowledge, intensive research and development in the field of knowledge engineering is required, capable of elevating it to the level of knowledge science, which will be able to solve knowledge processing problems of the same scale and complexity that are currently solved in data science using big data. An analysis of potential areas of research and development in a hypothetical knowledge science is presented, and some methods, models, algorithms, and technologies for processing large volumes of raw fragments of expert knowledge to serve the next generation of intelligent applications are considered.

The purpose of this study was to assess the processes of plant community formation on recultivated dumps of spent uranium-containing industrial waste from uranium deposit mines, as well as to identify the degree of impact of agro-climatic factors, agrochemical indicators of soils of recultivated dumps, and the level of residual ionizing radiation on the productivity of the emerging vegetation cover. Studies of plant colonization of recultivated Grachevsky and Shantobinsky uranium mine dumps located in Northern Kazakhstan were carried out. The mining and technical stage of reclamation consisted of planning a dump with slopes of 15° and covering it with a 1 m layer of chestnut soil. In total, 30-35 plant species are present in the dumps, the projective coverage is approximately the same (56.6-70.0%), and the herbage density is 15-16.6 plants/100 m2. As a result of the measures taken to recultivate the dumps, the intensity of the background ionizing radiation at the Grachevsky mine dump was in the range of 25-35 µR/hr and at the Shantobinsky mine dump 10-25 µR/hr, which indicates compliance with safety standards. The plant species which can be used for artificial plant colonization of uranium-containing waste dumps, were identified.