Quantification of mesoscale deformation-induced surface roughness in α-titanium

The phenomenon of mesoscale deformation-induced surface roughening in titanium polycrystals is examined experimentally and numerically. The evolution of the surface morphology under uniaxial tension is analyzed in terms of the standard and ad hoc roughness parameters and the fractal dimension. The statistical estimates are compared to the grain-scale stress-strain fields in order to reveal an interrelation between the in-plane plastic strains and out-of-plane surface displacements. A strong correlation with a determination coefficient of 0.99 is revealed between the dimensionless roughness parameter Rd and the corresponding in-plane plastic strain. The standard roughness parameters Ra and RRMS are shown to correlate linearly with the in-plane strains, but only for moderate tensile deformation, which is due to filtering out low-frequency components in the surface profiles. The fractal dimension DF changes with the subsection strains in a sawtooth fashion, with an abrupt drop in the neck region. The descent portions of the DF dependences are supposedly related to the appearance of low-frequency components in the structure of the surface profiles

“Vaccine Nationalism” As a Great Power Competition: Analysis from the Standpoint of the Securitization Theory

Introduction. State leaders and heads of international organizations argue that COVID-19 is a global security threat that requires international responses. However, to date, there is no stable international cooperation regime in the field of counteracting the virus, primarily at the level of vaccine development. Moreover, countries are competing in this area, considering primacy in the creation of a COVID-19vaccine not only as a step towards the fight against the virus, but as a tool to strengthen their international positions and increase international prestige and “soft power”. Methods and materials. The authors investigate the problem from the standpoint of the securitization theory, according to which national and international security threats are formed by political actors as speech acts and discursive practices. Analisys. From the standpoint of this theory, despite the fact that the COVID-19 pandemic is securitized at the national level in many countries, at the global level, this securitization discourse about COID-19 discourse is embedded in a broader macrosecuritization framework, which assumes that the dominant threats are associated with the confrontation of great powers. Results. The consequence of this is the legitimization of the policy of “vaccine nationalism” and the lack of international cooperation in the field of vaccine productio

Digital Diplomacy in Russian-European Relations: Cross-Cultural Aspects

The development of information and communication technologies and formation of the global information society actualizes the study of new directions in the evolution of diplomatic practice in the digital environment, including in the context of intercultural communication. The modern information revolution is characterized by the widespread and ever-growing use of social networks, blogs, wiki resources and other media platforms (labelled under the common term of Web 2.0 technologies). At the same time, the widespread use of Web 2.0 technologies and the increasing amount of time people all over the world spend there has a wide and profound impact on political and intercultural communication and diplomatic practice. A new phenomenon of digital diplomacy is gaining prominence among foreign policy tools of states and international organizations. Digital diplomacy can be defined as the use of social networks and Web 2.0 technologies in public diplomacy and international interaction by states and international organizations to achieve foreign policy goals and reach foreign audiences. According to the traditional view of digital diplomacy, which has developed in the academic literature, and is reflected in the works of authors such as M. Castells and J. Nye, it helps to strengthen network ties at the level of civil societies in different countries and thus reduces international conflicts. However, cultural differences and digital polarization can impede the potential of digital diplomacy. Today, almost all states and international organizations in the global arena are involved in the practice of digital diplomacy, and Russia is no exception. Russia actively participates in the digital diplomacy practice, by using social media and Web 2.0 tools as soft power instruments to introduce and explain foreign policy initiatives and reach foreign and domestic audiences, as stated in the Doctrine of the Information Security of Russian Federation of 2016. For Russia's foreign policy, relations with the EU countries and EU institutions are of particular importance, including in the digital sphere. However, even though both Russia and the EU countries make extensive use of digital diplomacy tools, the practice of horizontal network interaction mediated by digital technologies does not contribute to strengthening trust between countries and reducing conflicts. The authors consider incidents and allegations in the sphere of digital interaction and, based on the theory of digital polarization, conclude that the use of digital tools in horizontal interactions within digital diplomacy exacerbates intercultural differences between countries and increases conflict instead of improving mutual understanding

A correlation between deformation-induced surface roughness and in-plane plastic strain in an aluminum alloy at the mesoscale

cal studies on deformation-induced surface roughening in a commercial purity aluminum alloy are presented and discussed. Mesoscale surface profiles evolving in the experimental and numerical specimens in the course of tension are processed to reveal a correlation between roughness characteristics and in-plane plastic strains at the mesoscale. A dimensionless parameter calculated as a ratio of the rough profile length to the profile evaluation length has been used for quantitative estimations of the mesoscale roughness patterns. The dimensionless roughness parameter is shown to depend exponentially on the in-plane plastic strains at the mesoscale. The results support an early assumption tha

Mechanical aspects of nonhomogeneous deformation of aluminum single crystals under compression along [100] and [110] directions

The deformation behavior of aluminum single crystals subjected to compression along the [100] and [110] directions is numerically examined in terms of crystal plasticity. A constitutive model taking into account slip geometry in face-centered cubic crystals is developed using experimental data for the single-crystal samples with lateral sides coplanar to certain crystal planes. Two sets of calculations are performed using ABAQUS/Explicit to examine the features of plastic strain evolution in perfectly plastic and strain-hardened crystals. Special attention is given to the discussion of mechanical aspects of crystal fragmentation. Several distinct deformation stages are revealed in the calculations. In the first stage, narrow solitary fronts of plastic deformation are alternately formed near the top or bottom surfaces and then propagate towards opposite ends to save the symmetry of the crystal shape. The strain rate within the fronts is an order of magnitude higher than the average strain rate. The first stage lasts longer in the strain-hardened crystals, eventually giving way to an intermediate stage of multiple slips in different crystal parts. Finally, the crystal shape becomes asymmetrical, but no pronounced macroscopic strain localization has been revealed at any deformation stage. The second stage in perfectly plastic crystals relates to abrupt strain localization within a through-thickness band-shaped region, accompanied by macroscale crystal fragmentation. Stress analysis has shown that pure compression took place only in the first deformation stage. Once the crystal shape has lost its symmetry, the compressive stress in some regions progressively decreases to zero and eventually turns tensile

Modeling of 3D microstructures produced by additive manufacturing

Two approaches to simulating microstructures typical of additively manufactured (AM) materials are presented. First approach relies on the mathematical description of the microstructure evolution during metal AM process, taking into account complex physical processes involved. The numerical solution is based on a combination of the finite difference method for modeling AM thermal processes and the cellular automata method for describing the grain growth. The other approach provides fast generation of artificial 3D microstructures similar to those produced by AM by geometrical characteristics of grains, using the step-by-step packing method

Organization of Professional Retraining and Professional Development of Specialists in Technical Quality Control of Products

Рассматривается проблема низкого уровня квалификации персонала машиностроительного производства в области контроля качества продукции и обосновывается необходимость их повышения квалификации и профессиональной переподготовки. Показана процедура проектирования дополнительной профессиональной программы на основе профессионального и образовательного стандарта. Сформулированы положения успешной организации дополнительного профессионального образования.The problem of the low level of qualification of machine-building personnel in the field of product quality control is considered and the need for their further training and professional retraining is justified. The procedure of additional professional program design based on professional and educational standard is shown. The provisions of the successful organization of additional vocational education are formulated

Influence of insectocompost obtained by cultivation of the during beetle <i>Ulomoides dermestoides</i> on the ecological-trophic composition and development of soil and phytoparasitic nematodes

The purpose of the research is to study the effect of insect compost obtained as a result of the vital activity of insects of the Coleoptera order Ulomoides dermestoides on the quantitative and qualitative composition of soil nematodes of various ecological and trophic groups, as well as on the morphological and physiological state of plants and infection of tomato plants with root-knot nematodes.Materials and methods. Under laboratory conditions, soil containing a diverse fauna of nematodes was treated with 1% dry and 0.5; 0.75 and 1% aqueous solutions of biocompost. Insect compost was obtained by keeping the U. dermestoides on a dry nutrient mixture. Then a mixture of lawn grasses was sown in the ground. After 30 days, the composition of nematodes was analyzed. The ability of insect compost to suppress parasitic nematode species was studied using the tomato-knot nematode model system. Tomatoes were infected with Meloidogyne incognita at a rate of 500 larvae (J2) per plant and simultaneously treated with a 0.5% aqueous biocompost solution.Results and discussion. The insect compost U. dermestoides has an effect on quantitative and qualitative indicators in the community of soil nematodes, increasing the number of predatory and saprobiotic nematodes and displacing parasitic ones. And due to the content of various biologically active compounds, it affects the development of rootknot nematodes in tomato roots. When tomatoes are treated with an aqueous solution of insect compost, the infection score and the number of nematodes that penetrate the roots are reduced. The introduction of compost when growing a mixture of lawn grasses and tomatoes can improve the condition of the plants