ЗАКОНОМІРНОСТІ КОРОЗІЙНОГО РОЗТРІСКУВАННЯ ТРУБНОЇ СТАЛІ 10Г2ФБ У МОДЕЛЬНОМУ ГРУНТОВОМУ СЕРЕДОВИЩІ ЗА КАТОДНОЇ ПОЛЯРИЗАЦІЇ

Purpose. Investigate the regularities of corrosion cracking of 10G2FB steel under cathodic protection.Methodology. The following methods were used: slow strain rate, scanning electron microscopy, electrolytic hydrogenation, mass measurement.Results. The regularities of corrosion cracking of pipe steel 10G2FB in near neutral soil environment NS4 in the range of potentials from the corrosion potential to -1.2 V were investigated. According to the results of a complex of corrosion-mechanical, electrochemical and physical studies, it was found that with a shift in the cathodic polarization potential in the range of -0,75 V ® -0,95 V ® -1,05 V ® -1,2 V ® -0.95 V the coefficient of susceptibility of this steel to stress corrosion cracking KS increases correspondingly, 1,09 ® 1,11 ® 1,13 ® 1,26. The concentration of hydrogen which penetrating into steel at these potentials changes nonmonotonically: 0 ® 0 ® 0,057 ® 0,018 mol/dm3. The rate of residual corrosion with a potential shift in the series Еcor ® -0,75 V ® -0,95 V ® -1,05 V decreases first sharply, then slowly: 0.035 mm/year ® 0.005 mm/year ® 0.0009 mm/year ® 0.0004 mm/year, i.e. at high cathodic potentials, the applied polarization is spent on the decomposition of the aqueous electrolyte with the release of hydrogen, which penetrates into the steel and causes brittle cracking, which is confirmed by an increasing in the part of brittle fracture in the surface morphology of the specimens.Scientific originality. New results of fundamental research concerning the regularities of stress-corrosion cracking of ferrite-pearlite class steel of pipe assortment 10G2FB under conditions of cathodic protection in the range of potentials from the corrosion potential to -1.2 V have been obtained. It was revealed that a feature of the effect of cathodic polarization in the indicated range of potentials when assessing the tendency to stress corrosion cracking by the KS coefficient is an increasing in the relative narrowing and a decrease in the relative elongation, which generally indicates the embrittlement of the metal under the contact with corrosive medium and potential. Strength characteristics remain almost the same. The greatest tendency to stress-corrosion cracking is observed at a polarization potential of -1.0 V or more negative.Practical value. The developed methodology for a complex study of the regularities of stress- corrosion cracking was used for study of 10G2FB steel of the pipe assortment in a model soil environment NS4 under conditions simulating operating conditions. The new data obtained on the regularities of stress-corrosion cracking of steel will be useful for preventing the stress-corrosion cracking of main gas pipelines during operation.

Elastic Scattering of Slow Electrons by Noble Gases—The Effective Range Theory and the Rigid Sphere Model

We report on an extensive semi-empirical analysis of scattering cross-sections for electron elastic collision with noble gases via the Markov Chain Monte Carlo-Modified Effective Range Theory (MCMC−MERT). In this approach, the contribution of the long-range polarization potential (∼r−4) to the scattering phase shifts is precisely expressed, while the effect of the complex short-range interaction is modeled by simple quadratic expression (the so-called effective range expansion with several adjustable parameters). Additionally, we test a simple potential model of a rigid sphere combined with r−4 interaction. Both models, the MERT and the rigid sphere are based on the analytical properties of Mathieu functions, i.e., the solutions of radial Schrödinger equation with pure polarization potential. However, in contrast to MERT, the rigid sphere model depends entirely upon one adjustable parameter—the radius of a hard-core. The model’s validity is assessed by a comparative study against numerous experimental cross-sections and theoretical phase shifts. We show that this simple approach can successfully describe the electron elastic collisions with helium and neon for energies below 1 eV. The purpose of the present analysis is to give insight into the relations between the parameters of both models (that translate into the cross-sections in the very low energy range) and some “macroscopic” features of atoms such as the polarizability and atomic “radii”.

Immune Polarization Potential of the S. aureus Virulence Factors SplB and GlpQ and Modulation by Adjuvants

Protection against Staphylococcus aureus is determined by the polarization of the anti-bacterial immune effector mechanisms. Virulence factors of S. aureus can modulate these and induce differently polarized immune responses in a single individual. We proposed that this may be due to intrinsic properties of the bacterial proteins. To test this idea, we selected two virulence factors, the serine protease-like protein B (SplB) and the glycerophosphoryl diester phosphodiesterase (GlpQ). In humans naturally exposed to S. aureus, SplB induces a type 2-biased adaptive immune response, whereas GlpQ elicits type 1/type 3 immunity. We injected the recombinant bacterial antigens into the peritoneum of S. aureus-naïve C57BL/6N mice and analyzed the immune response. This was skewed by SplB toward a Th2 profile including specific IgE, whereas GlpQ was weakly immunogenic. To elucidate the influence of adjuvants on the proteins’ polarization potential, we studied Montanide ISA 71 VG and Imject™Alum, which promote a Th1 and Th2 response, respectively. Alum strongly increased antibody production to the Th2-polarizing protein SplB, but did not affect the response to GlpQ. Montanide enhanced the antibody production to both S. aureus virulence factors. Montanide also augmented the inflammation in general, whereas Alum had little effect on the cellular immune response. The adjuvants did not override the polarization potential of the S. aureus proteins on the adaptive immune response.

Electron-impact ionization of the Pb atom

Electron-impact ionization cross sections are calculated for the ground configuration of the Pb atom. Time-dependent close-coupling cross sections for the direct ionization of the 6s and 6p subshells leading to single ionization are calculated with and without a polarization potential. Configuration-average distorted-wave cross sections for the direct ionization of the 6s and 6p subshells leading to single ionization are also calculated with and without a polarization potential. We find the time-dependent close-coupling cross sections using a polarization potential to be in good agreement with convergent-close-coupling cross sections using a polarization potential. The total direct ionization cross sections are compared to two sets of experimental measurements. The differences between the direct ionization cross sections and the experimental measurements are mainly due to indirect ionization cross sections coming from the $$6s^2 6p^2 \rightarrow 6s 6p^3$$ 6 s 2 6 p 2 → 6 s 6 p 3 excitation followed by autoionization. GraphicAbstract

EXPRESS: Political Polarization: Challenges, Opportunities, and Hope for Consumer Welfare, Marketers, and Public Policy

Political polarization is a marked political division in the population, characterized by multiple manifestations. We argue that it can impact consumer psychology, which in turn influences marketers, policy makers, and consumer welfare. The present work introduces the construct of political polarization to the marketing literature, and shows how it serves as a novel challenge for various marketing stakeholders. For consumers, we propose that political polarization increases the salience of political identities, alters inter- and intra-group dynamics, and amplifies cognitive biases. These effects negatively impact consumer welfare, including financial welfare, relationships, mental and physical health, and societal interests. For marketers, polarization introduces a challenge to both be more socio-politically engaged while also navigating competing political interests. Polarization also creates new opportunities and challenges for segmentation, targeting, loyalty, and impacts product offerings. For policy makers, political polarization creates policy gaps, impedes the implementation of policy, and obstructs governance. Building from these insights, we consider the drawbacks and overlooked benefits of political polarization, potential remedies, and directions for future research.

On the pipeline polarization in the case of insulation delamination from its surface

The cathodic protection parameters for two pipelines with a diameter of 1420 mm were calculated. The protection zone for the first pipeline is 6 km long and for the second one it is 5 km. The cathode station current is 12,9 A for the first pipeline and 4 A for the second one. There are a damage and detachment of pipeline insulation, andconsequently a thin layer of electrolyte is located in the detachment area between the metal surface and the insulation. Almost the entire surface of the pipeline has polarization potential. For the first pipeline, the values of the protection potential at neighboring measurement points change quite dramatically, the difference between them can reach tenths of a volt. The polarization current density at the ends of the protection zone is quite small, and accordingly the polarization potential is close to the corrosion potential. But in the vicinity of the drainage point, these values are much larger. The situation is almost the opposite for the second pipeline, where the cathode station current is 4 A. The current density is almost equally distributed throughout the protection zone, slightly larger at its ends. The polarization potential changes accordingly. Its values are larger than the first case. In the cathodic protection, the potential of the pipeline relative to ground zero is important. Its average value depends on the magnitude of the cathode station current. Its graph intersects the lower part of the protection potential graph in the first case and the middle of the graph in the second. The protection potential is the difference between the potential of the pipeline and the earth surface. In the first case, in the vicinity of the drainage point this difference is much larger inside compared to the ends of the zone. As a conclusion, in the practice of cathodic protection it is important to regulate the value of the cathode station current in order to achieve the optimum protection. Keywords: delamination, protection potential, polarization current density.