المؤلفون: R. Yu. Galimzyanova, Yu. N. Khakimullin, Maria S. Lisanevich

المصدر: Polymer Science, Series D. 14:42-46

مصطلحات موضوعية: 010407 polymers, Materials science, Polymers and Plastics, General Chemical Engineering, General Chemistry, Carbon black, Butyl rubber, Adhesion, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Adhesion strength, Viscosity, chemistry.chemical_compound, chemistry, Cohesion (geology), Composite material, Dispersion (chemistry), Duralumin

الوصف: Results of studies of the effect of carbon black of P-803, P-324, and P-234 brands on cohesion strength, adhesion (to glass and duralumin), and the viscosity of nonhardening sealants based on butyl rubber are given. It is shown that the degree of cohesion and adhesion strength, while effective viscosity correlates with the dispersion of carbon black.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::b2385cbb4fa30d8b85104191ee93e5e4
https://doi.org/10.1134/s1995421221010081

المؤلفون: D. N. Lyubimov, V. I. Kolesnikov, I. V. Kolesnikov, I. S. Gershman

المصدر: Physical Mesomechanics. 23:509-513

مصطلحات موضوعية: 010302 applied physics, Materials science, Solid-state physics, Hamaker constant, 02 engineering and technology, Surfaces and Interfaces, Adhesion, Hamaker theory, Condensed Matter Physics, 01 natural sciences, Rubbing, 020303 mechanical engineering & transports, 0203 mechanical engineering, Mechanics of Materials, 0103 physical sciences, Cohesion (geology), General Materials Science, Adhesive, Composite material

الوصف: The paper is a theoretical study of mechanically activated processes in tribocontact, which lead to the formation of a lubricating film between rubbing bodies. The adhesive aspect of tribofilm formation is considered using the condition of the mechanical activation of the friction surface. This condition is satisfied when the adhesion energy becomes greater than the cohesion energy. The Hamaker constant is used to describe not only the adhesive interaction during friction, but also the amount of matter transferred when the mechanical activation condition is met. It is shown that the adhesive effect decreases with the second power of the distance from the friction surface. A relationship is derived that relates tribological characteristics to the Hamaker constant as the fundamental characteristic of the material. It is shown how the friction coefficient in the steady-state regime depends on the counterbody material and the antifriction transfer film material. Numerical results are compared to experimental data.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::e8cf640ef2d76c5f0e566a1ee5aa6b02
https://doi.org/10.1134/s1029959920060065

المؤلفون: S. P. Bakhaeva, D. V. Gur’ev

المصدر: Journal of Mining Science. 56:20-28

مصطلحات موضوعية: 0211 other engineering and technologies, Geology, 02 engineering and technology, Geotechnical Engineering and Engineering Geology, Loam, Friction angle, Cohesion (geology), Environmental science, Spatial variability, Geotechnical engineering, Soil strength, Statistical processing, Water content, 021102 mining & metallurgy, 021101 geological & geomatics engineering

الوصف: Based on the analysis, generalization and statistical processing of experimental data, the guideline values are determined for the physical and mechanical properties of loamy soil for construction of earthfill dams at liquid mining waste storages. A close parabolic relationship is found between the cohesion, internal friction angle and natural moisture content of soil. The authors present the method of real-time prediction of earthfill dam parameters with regard to spatial variability of soil strength.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::40cc65d64d8900fef1cf5056c5effb2d
https://doi.org/10.1134/s1062739120016442

المؤلفون: Vagif M. Mirsalimov

المصدر: Journal of Mining Science. 56:9-19

مصطلحات موضوعية: Isotropy, 0211 other engineering and technologies, Geology, Geometry, 02 engineering and technology, Geotechnical Engineering and Engineering Geology, Gravitation, Tectonics, Cohesion (geology), Contact zone, Rock mass classification, Partial closure, 021101 geological & geomatics engineering, 021102 mining & metallurgy

الوصف: The article considers the problem on compression of an isotropic medium with a variable-width slot with cohesive zones at the ends. Under the action of tectonic and gravitational forces in rock mass, contact zones appear between the slot surfaces. The author analyzes the case of a number of the contact zones between the slot surfaces. In a part of the contact zone, cohesion of the slot edges takes place, while sliding is possible in the other part. The unknown parameters of the partial closure of the slot are found by solving a system of singular integro-differential equations. The contact stresses, the cohesion forces, as well as the sizes of the contact areas, cohesion zones and pre-fracture end zones are determined.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::3e5698e39ffb5e104ce166756e2284c8
https://doi.org/10.1134/s1062739120016430

المؤلفون: E. Yu. Ermilova, O. V. Stoyanov, E. M. Yagund, P. E. Bulanov, R. Z. Rakhimov

المصدر: Polymer Science, Series D. 12:454-458

مصطلحات موضوعية: Cement, Materials science, Polymers and Plastics, General Chemical Engineering, Superplasticizer, General Chemistry, law.invention, Electrokinetic phenomena, Portland cement, Chemical engineering, law, Cohesion (geology), Kaolinite, Clay minerals, Dispersion (chemistry)

الوصف: Superplasticizers are one of the most widespread chemical additives in the concrete industry. They peptize cement floccules and increase the mobility of concrete mixes at a decreased water-to-cement ratio due to the release of immobilized water, a decrease in the internal friction coefficient, and an increase in electrostatic repulsion of particles due to a significant change of their electrokinetic potential. A new generation of superplasticizers based on polycarboxylate ester have been developed in recent decades, which possesses a different dispersion ability of cement particles than do old-generation superplasticizers. However, the molecules of polycarboxylate superplasticizer are more sensitive to clay minerals in concrete mixes. The effect of the strength characteristics of the ground, such as angle of internal friction and specific cohesion, has been studied. Specific interactions between kaolinite mineral and various superplasticizers have been studied using IR spectroscopy. Intrinsic bands in IR spectra of superplasticizers corresponding to their functional groups have been interpreted.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::456f3056abdc12c85b9e4c1be0aeadd7
https://doi.org/10.1134/s199542121904004x

المؤلفون: E.L. Alkova, S. V. Panishev, M.S. Maksimov

المصدر: Journal of Mining Science. 55:371-375

مصطلحات موضوعية: Materials science, 0211 other engineering and technologies, Geology, 02 engineering and technology, Geotechnical Engineering and Engineering Geology, Grain size, Excavatability, Friction angle, Cohesion (geology), Composite material, Rock mass classification, Water content, 021102 mining & metallurgy, 021101 geological & geomatics engineering

الوصف: The regularities of change in mechanical characteristics of heterogeneous structure of frozen geomaterials depending on grain size composition, temperature, moisture content and density of sample packing are determined. It is found that the major influence is exerted on the shear strength, internal friction angle and cohesion in the samples structurally commensurable with blasted rock mass by temperature, moisture content and packing. In the size range of 10–40 mm of inclusions in a sample, the internal friction angle drops by 2 times while the cohesion jumps by the same value. It is shown that blasted frozen rocks prone to re-adfreezing is a complex medium possessing properties of intact uniform rock mass.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::60a448e966e9a7d656ea1bacbe2e41f0
https://doi.org/10.1134/s1062739119035684

المؤلفون: Konstantin Ustinov, V. I. Karev, Dmitry Klimov, Yu. F. Kovalenko

المصدر: Physical Mesomechanics. 21:216-222

مصطلحات موضوعية: 010504 meteorology & atmospheric sciences, Geometry, 02 engineering and technology, Surfaces and Interfaces, Condensed Matter Physics, 01 natural sciences, Internal friction, Physics::Geophysics, 020303 mechanical engineering & transports, 0203 mechanical engineering, Shear (geology), Mechanics of Materials, Bed, Cohesion (geology), Fracture (geology), General Materials Science, Hill yield criterion, Anisotropy, Triaxial compression, Geology, 0105 earth and related environmental sciences

الوصف: The paper proposes a deformation and fracture model for anisotropic stratified rocks and presents theoretical and experimental data on how the rock strength and fracture geometry are influenced by principal stresses and their orientation to bedding planes. Two possible mechanisms are considered for rock fracture under true triaxial load: along bedding planes of weakness and along planes in which Mohr-Coulomb stresses reach a critical combination with cohesion coefficients and internal friction angles typical of the rock. The transition of rocks to inelastic deformation is described in the context of two criteria of which one accounts for the above fracture mechanisms and the other, being a semi-empirical analogue of the Hill yield criterion, accounts for the effect of normal stress. The experimental data presented are for the strain and strength properties of rocks sampled from the Fedorovskoye and Talakanskoye oil and gas fields and tested on an original loading system for true triaxial compression with lateral pressure (similar to the Karman scheme) and for generalized shear (three unequal and nonmonotonic principal stresses). The experimental and theoretical results, including total stress-strain curves, are in good qualitative agreement and demonstrate the possibility to evaluate the parameters entered in the model from tests of particular rocks.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::5efa5d985a682258dccc4a9a4f9504a8
https://doi.org/10.1134/s1029959918030050

المؤلفون: D. D. Khaidapova, E. Yu. Milanovskii, V. V. Chestnova, Evgeny Shein

المصدر: Eurasian Soil Science. 49:890-897

مصطلحات موضوعية: chemistry.chemical_classification, Materials science, Soil test, Soil Science, Soil science, 04 agricultural and veterinary sciences, 010501 environmental sciences, Atterberg limits, 01 natural sciences, Viscoelasticity, Humus, chemistry, Rheology, 040103 agronomy & agriculture, Cohesion (geology), 0401 agriculture, forestry, and fisheries, Geotechnical engineering, Organic matter, Water content, 0105 earth and related environmental sciences, Earth-Surface Processes

الوصف: Rheological parameters of humus horizons from typical chernozems under different land use—on a virgin land (unmown steppe) and under an oak forest, long-term black fallow, and agricultural use—have been studied by the amplitude sweep method with an MCR-302 modular rheometer at water contents corresponding to swelling limit and liquid limit. From the curves of elastic and viscous moduli, the ranges of elastic and viscoelastic (plastic) behavior of soil pastes—as well as that of transition from viscoelastic to viscous behavior—have been determined. It has been shown that the rheological behavior is largely determined by the content of organic matter, which can act as a binding agent structuring the interparticle bonds and as a lubricant in the viscous-flow (plastic) state of soil pastes. Soil samples enriched with organic matter (virgin land, oak forest, forest belt) have a more plastic behavior and a higher resistance to loads. Soil samples with the lower content of organic matter (long-term fallow, plowland) are characterized by a more rigid cohesion of particles and a narrower range of load resistance. Soil pastes at the water content of liquid limit have a stronger interparticle cohesion and a more brittle behavior than at the water content of swelling limit. Methodological aspects of testing soil pastes at the constant sample thickness and the controlled normal load have been considered. For swelling soil samples, tests under controlled normal load are preferred.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::d063590dbc5c8735cde320c5bd937177
https://doi.org/10.1134/s1064229316080044

المؤلفون: G. A. Larionov, Z. P. Kiryukhina, O. G. Bushueva, N. G. Dobrovol’skaya, L. F. Litvin, S. F. Krasnov

المصدر: Eurasian Soil Science. 49:546-550

مصطلحات موضوعية: Water erosion, Chemistry, Bond, Soil Science, 04 agricultural and veterinary sciences, 010501 environmental sciences, 01 natural sciences, Erosion rate, Flow velocity, 040103 agronomy & agriculture, Cohesion (geology), 0401 agriculture, forestry, and fisheries, Geotechnical engineering, 0105 earth and related environmental sciences, Earth-Surface Processes

الوصف: It has been experimentally shown with monoaggregate model samples of chernozemic soil as an example that the weakening of cohesion between soil particles is due to the molecular interaction of soil particles with water as a dipole substance rather than to the hydraulic forces of the flow. Therefore, soil erosion should be considered as a two-stage process. First, the bonds between particles are weakened due to the interaction of soil particles with water; then, the particles that lost bonds with neighboring ones are entrapped by the flow. Thus, the erosion rate of a consolidated soil is determined by the destruction of bonds between particles during their interaction with water, rather than the flow velocity, although this factor also affects the erosion rate.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::3a07bb21ac72af3cf3fc5e20ce4ae6b8
https://doi.org/10.1134/s1064229316050100

المؤلفون: Hadi Haeri, Vahab Sarfarazi

المصدر: Journal of Mining Science. 52:245-257

مصطلحات موضوعية: business.industry, 020502 materials, 0211 other engineering and technologies, Geology, 02 engineering and technology, Structural engineering, Classification of discontinuities, Geotechnical Engineering and Engineering Geology, 0205 materials engineering, Shear (geology), Friction angle, Ultimate tensile strength, Shear strength, Cohesion (geology), Geotechnical engineering, Bearing capacity, Direct shear test, business, 021101 geological & geomatics engineering

الوصف: Presence of rock bridges in rock masses would increase the bearing capacity of non-persistent discontinuities. This increase is because of the cohesion and friction angle of the internal support system rendered by the rock bridges. In this article the effect of the number, area and configuration of the rock bridges on their shear properties are investigated. A total of 36 various models with dimensions of 30×30×30 cm of plaster specimens were fabricated simulating the open joints possessing 1, 2, 3 rock bridges respectively. The introduced rock bridges were of longitudinal and latitudinal configuration. The area of these rock bridges were 300, 450 and 600 cm2 out of the total fixed area of 900 cm2 respectively. The fabricated specimens were subjected to shear tests under 4 different normal loads (20, 30, 40 and 50 kg/cm2) in order to investigate the shear parameters. The results shows that, shear failure occur in longitudinal rock bridge under these normal loads. But tensile failure occur in latitudinal rock bridge when rock bridge continuity was low and shear failure occurs in latitudinal rock bridge when rock bridge area was high. This behavior occurs in each configuration and normal load. The results were indicating that the cohesion of the longitudinal rock bridges is higher than those of the latitudinal rock bridge for similar areas. It was also noticed that in the fixed area of the longitudinal rock bridges the cohesion remains constant with the change in the number of bridges. But the cohesion of the latitudinal rock bridges increase with the increase of the number of rock bridges (under fixed area of the rock bridges). The friction angel was behaved constant all through the tests carried out for various models. In the final section of this article, two equations are introduced for determining the cohesion strength in longitudinal and latitudinal rock bridges.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::405ab58f1d550b94a405de22ca8aeb7a
https://doi.org/10.1134/s1062739116020370