Electromagnetic cascade masquerade: a way to mimic γ\gamma--axion-like particle mixing effects in blazar spectra

Context. Most of the studies on extragalactic {\gamma}-ray propagation performed up to now only accounted for primary gamma-ray absorption and adiabatic losses ("absorption-only model"). However, there is growing evidence that this model is oversimplified and must be modified in some way. In particular, it was found that the intensity extrapolated from the optically-thin energy range of some blazar spectra is insufficient to explain the optically-thick part of these spectra. This effect was interpreted as an indication for {\gamma}-axion-like particle (ALP) oscillation. On the other hand, there are many hints that a secondary component from electromagnetic cascades initiated by primary {\gamma}-rays or nuclei may be observed in the spectra of some blazars. Aims. We study the impact of electromagnetic cascades from primary {\gamma}-rays or protons on the physical interpretation of blazar spectra obtained with imaging Cherenkov telescopes. Methods. We use the publicly-available code ELMAG to compute observable spectra of electromagnetic cascades from primary {\gamma}-rays. For the case of primary proton, we develop a simple, fast and reasonably accurate hybrid method to calculate the observable spectrum. We perform the fitting of the observed spectral energy distributions (SEDs) with various physical models: the absorption-only model, the "electromagnetic cascade model" (for the case of primary {\gamma}-rays), and several versions of the hadronic cascade model (for the case of primary proton). We distinguish the following species of hadronic cascade models: 1) "basic hadronic model", where it is assumed that the proton beam travels undisturbed by extragalactic magnetic field and that all observable {\gamma}-rays are produced by primary protons through photohadronic processes with subsequent development of electromagnetic cascades /abridgedComment: Accepted by A&A. 25 pages, 31 figures. Corrected fig. 5, fig. 7; new explanations for fig. 6--7; several typos fixed wrt v.

Stress-strain state and loss of stability of anisotropic thermal coating under thermal shock

The deformation behavior of thermal barrier coatings has been investigated. The mechanism of occurring instabilities in such coatings based on their representation in the form of a plate located on an elastic foundation has been studied. Loss of stability manifests itself in the form of a doubly periodic system of intrusion and extrusion zones that is qualitatively consistent with the well-known experimental results. Typical features of stability loss and its dependence on the properties of conjugated materials have been investigated by the example of the thermal loading simulation of the copper specimen with a protective ceramic coating. The influence of the thermo-mechanical properties anisotropy of the coating material on the character of the emerging instability has been estimated

Cutting capacity and strength of single grinding grains

The results received at research of the cutting ability and durability of single grinding grains are presented in article. In particular influence of such parameters as a form and a corner of orientation of grinding grain was considered

Impact of defectiveness on the parameters of the acoustoelectric transformations in heterogeneous non-metallic materials

The article studies acoustoelectric transformations of concrete with a crack. The research presents three-dimensional modeling and 3D visualization of wave processes in a concrete sample with a surface crack. The parameters of the electrical response are found to reflect the processes of interaction between the acoustic wave front and the defect and boundaries of the sample

Use of methods of wave processes modeling for control of defectiveness of non-metallic materials

The paper presents theoretical and experimental research of an electrical response to the elastic impulse excitation of concrete samples. The authors describe three-dimensional modeling and 3D visualization of wave processes and calculate the parameters of an electrical signal from defect-free and defective samples. The research demonstrates the comparison of design data with experimental outcomes; good precision of data was obtained

Impact of defectiveness on the parameters of the acoustoelectric transformations in heterogeneous non-metallic materials

The article studies acoustoelectric transformations of concrete with a crack. The research presents three-dimensional modeling and 3D visualization of wave processes in a concrete sample with a surface crack. The parameters of the electrical response are found to reflect the processes of interaction between the acoustic wave front and the defect and boundaries of the sample

Use of Simulation Methods of Wave Processes for Non-Destructive Testing of Concrete Products of Different Geometrical Size

Theoretical and experimental research of electrical responses under pulsed mechanical excitation of different size concrete products was carried out. Comparison of calculated and experimental data shows very close agreement. The obtained results will help to develop new opportunities to improve the method of non-destructive testing of concrete by creating a bank of calculated electrical responses from products of different geometrical arrangement and elastic response and using them as standard samples for defectiveness evaluation of products according to previously established criteria

TERMINATION OF CONTRACTOR'S AGREEMENT ON PROJECT AND EXPLORATION WORKS

RETRACTION:Date of retraction: 24.12.2021Reason for retraction: Plagiarism in the publicationAdditional information about the causes of retraction:The article published in the scientific Journal “Actual Problems of Economics and Law” (2010. No. 2. Pp. 117–123) under the title “Termination of contractor’s agreement  on project and exploration works”, under the authorship of A. M. Lyukshin is withdrawn by an editor with the consent of the publisher.Retraction is due to the double publication: Pravovoe regulirovanie predprinimatel'skoi deyatel'nosti: obshchee i osobennoe [monografiya]. Kazan, 2010

ПОВЫШЕНИЕ РАБОТОСПОСОБНОСТИ ШЛИФОВАЛЬНЫХ ЛЕНТ

Processing by grinding tapes gained big distribution in various areas of mechan-ical engineering. At the same time, the analysis of use of grinding tapes shows that efficiency of their application is rather low. One of the main reasons causing such result, consists that tapes are made of grinding grains with any form and (usually) chaotic arrangement on a basis surface. This work is devoted to increase of operability of grinding tapes due to use of grains with a controlled form and their orientation on a basis.Обработка шлифовальными лентами получило большое распространение в различных областях машиностроения. Вместе с тем, анализ использования шлифовальных лент показывает, что эффективность их применения относительно невысока. Одна из основных причин, обуславливающих такой результат, состоит в том, что ленты изготавливаются из шлифовальных зерен с произвольной формой и (как правило) хаотичным расположением на поверхности основы. Данная работа посвящена повышению работоспособности шлифовальных лент за счет использования зерен с контролируемой формой и ориентацией их на основе