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The fiber formation process via the uniaxial stretching jet of concentrated polyacrylonitrile solutions in dimethyl sulfoxide has been investigated. Data on viscoelastic properties obtained by oscillatory shear rheometry have been compared with the evolution of jet thinning during stretching. It was found that at a fixed temperature and moderate air humidity (20%), the jet thinning process involves an initial rapid viscous thinning followed by phase separation and the formation of solid fibers coated with solvent droplets. Changes in morphology as the solution transforms into solid fiber were analyzed using cryo-microscopy. It was demonstrated that at the final thinning stages there exists an increase in a solvent concentration in the near-surface layers of the jet/fiber. Finally, the role of air humidity was analyzed. Two possible scenarios of fiber formation were considered: predominantly due to uniaxial deformation or through coagulation of solution with moisture from the air humidity. Comparative morphological analysis of prepared fiber cross sections showed that monolithic fibers with homogeneous transverse morphology are obtained in the case of strain-induced formation. In contrast, fibers obtained due to phase separation induced by air humidity have gradient porosity. The mechanisms underlying the observed behavior are discussed. [ABSTRACT FROM AUTHOR]

New results have been presented for the T20 component of the tensor analyzing power of the γd → ppπ– reaction measured in the photon energy range from 300 to 600 MeV. The data have been obtained from the statistical sample collected at the VEPP-3 accelerator in 2021. The T20 component has been separated using the asymmetry of the reaction yield, which is due to change in the sign of the tensor polarization of the deuterium target. The experimental data have been compared to the simulation within the spectator model including the interaction between particles in the final state. [ABSTRACT FROM AUTHOR]

In this paper, we present new experimental results for the tensor analyzing power of the reaction in the region of low proton energies. The results are presented in the photon energy range of and the proton energy range of . The paper uses the experimental statistics accumulated at the VEPP-3 accelerator complex in 2013. To identify the events of the reaction , we used the registration of the proton and two -quanta from the decay in coincidence. The experimental results were compared with the results of statistical simulation. To perform the statistical simulation, we used the unitary isobar model MAID 2007 for the elementary pion-nucleon photoproduction amplitude and took into account and rescattering in the final state of the reaction . [ABSTRACT FROM AUTHOR]

The paper presents new results for the T20 analyzing power tensor component of the γd→pnπ0 reaction in the photon energy range of 300 MeV < Eγ < 500 MeV. The experimental statistics accumulated in 2013 at the VEPP-3 accelerator-storage complex using an internal tensor-polarized gaseous deuterium target has been used. The reaction events are identified by the coincidence registration of the proton and two gamma quanta from the neutral pion decay. To determine the T20 component, the asymmetry of the yields with respect to the change in the sign of the tensor polarization of the deuterium target is measured. Experimental results are compared with the theoretical calculations for the MAID 2007 model of the amplitude used as the elementary pion-nucleon photoproduction amplitude and contributions of pion-nucleon and nucleon-nucleon rescattering are taken into account. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to elaborate new calculation schemes for evaluating the strength parameters of railway rolling stock parts with non-local properties of surface layers in the presence of elliptical stress concentrators. Design/methodology/approach: Using the proposed approaches of developed mathematical modelling and open software for calculating FEniCS, it were established the most dangerous angles of stress concentrator orientation and the required thickness of the hardened zones of parts, which ensures their minimum softening during operation. Findings: It is shown that for an elliptical stress concentrator with any orientation angle, there is a certain key size of surface hardening thickness, the exceeding the value of which does not have influence on the operational strength of the parts, but rise the price of technological operations. Research limitations/implications: In this paper proposes a method for computation the impact of the orientation of the surface elliptical stress concentrators on the contact strength of parts under conditions of dominate friction power loads. Practical implications: The obtained results were used to set the modes of plasma hardening, which increase the contact strength of railway parts with elliptical stress concentrators. Originality/value: Using the approaches of contact mechanics, mathematical and computer modelling, methods of controlling the contact strength of the parts with the surface elliptical stress concentrators were proposed for the first time. [ABSTRACT FROM AUTHOR]

We present the first accurate results of measurements of the tensor analyzing power component T 20 for the coherent neutral pion photoproduction on the deuteron. The measurements were performed at the Budker Institute of Nuclear Physics at VEPP-3 storage ring using the internal tensor polarized deuterium target. The measurements cover the region of photon energy from 200 to 450 MeV and the region of the center-of-mass pion polar angle from 100 to 140 degrees. The results obtained are compared with predictions of several theoretical models. [ABSTRACT FROM AUTHOR]