Влияние межчастичного взаимодействия в ансамбле неподвижных суперпарамагнитных феррочастиц на cтатические, магнитные и термодинамические свойства системы

This paper presents a study of the effect of the interparticle dipole-dipole interaction on the static, thermodynamic, and magnetic properties of the ensemble of stationary superparamagnetic particles in the external magnetic field. The relaxation of the magnetic moment of the model ferroparticles occurred by the Néel mechanism. The directions of the easy axes of all particles were assumed to be parallel to each other, but at the angle to the direction of the external magnetic field. The direction of the easy axes was described using the polar and azimuth angles. The potential energy of the system includes a single-particle dipole-axial interaction, a single-particle dipole-field interaction and long-range interparticle dipole-dipole correlations. In the system, two variants of the distribution of ferroparticles over the volume of the container are considered: in the nodes of a simple cubic lattice and randomly. The described model is studied theoretically by expanding the Helmholtz free energy into a classical virial series up to the second virial coefficient. Using the new theory, the contribution of dipole-dipole interactions in the changes in the magnetic susceptibility, magnetization, and heat capacity of the system is estimated, and the results are represented graphically. Important information necessary to the development and synthesis of new magnetic materials with controlled properties is provided. © 2021 Tyumen Scientific Centre of Siberian. All right reserved.This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the framework of the Ural Mathematical Center project No 075–02-2021-1387

Disappointing model for ultrahigh-energy cosmic rays

Data of Pierre Auger Observatory show a proton-dominated chemical composition of ultrahigh-energy cosmic rays spectrum at (1 - 3) EeV and a steadily heavier composition with energy increasing. In order to explain this feature we assume that (1 - 3) EeV protons are extragalactic and derive their maximum acceleration energy, E_p^{max} \simeq 4 EeV, compatible with both the spectrum and the composition. We also assume the rigidity-dependent acceleration mechanism of heavier nuclei, E_A^{max} = Z x E_p^{max}. The proposed model has rather disappointing consequences: i) no pion photo-production on CMB photons in extragalactic space and hence ii) no high-energy cosmogenic neutrino fluxes; iii) no GZK-cutoff in the spectrum; iv) no correlation with nearby sources due to nuclei deflection in the galactic magnetic fields up to highest energies.Comment: 4 pages, 7 figures, the talk presented by A. Gazizov at NPA5 Conference, April 3-8, 2011, Eilat, Israe

TO THE QUESTION ABOUT THE REASONS DESTOCKING FISHIN THE CASPIAN SEA

Aim. To identify the reasons for the decline of fish stocks in the Caspian sea. Location. The Caspian sea. Methods. When adverse effects of multiple abiotic factors, the other part indicates the important role of fisheries. How fair this point of view will try to answer in this paper. Consider long-term changes in the average water temperature in the Northern Caspian sea. Results. Considered abiotic and biological factors ( prey base) productivity of the Northern Caspian sea could cause catastrophic ( tenfold) reduction of fish stocks. Evidence of this is shown in table. 2 which shows that external factors do not provide a clear correlation with the yield of fish, more important are the internal factors related to the impact of fishing. Main conclusions. You should pay very close attention to human factors and in particular on the volume of catch, location and time fishing and more time to assess how rational our modern craft

Complex Action Support from Coincidences of Couplings

Our model \cite{ownmMPP}\cite{SIMPP} with complex action in a functional integral formulation with path integrals extending over all times, past and future, is reviewed. Several numerical relations between coupling constants are presented as supporting evidence. The new evidence is that some more unexplained coincidences are explained in our model: 1) The "scale problem" is solved because the Higgs field expectation value is predicted to be very small compared to say some fundamental scale, that might be the Planck scale. 2) The Higgs VEV need not, however, to be just zero, but rather is predicted to be so that the running top-Yukawa coupling just is about to be unity at this scale; in this way the (weak) scale easily becomes "exponentially small". Instead of the top-Yukawa we should rather say the highest flavour Yukawa coupling here. These predictions are only achieved by allowing the principle of minimization of the imaginary part of the action SI(history) to to a certain extent adjust some coupling constants in addition to the initial conditions. If Susy-partners are not found in LHC, it would strengthen the need for "solution" of the hierarchy or rather scale problem along the lines of the present article.Comment: only text. Some printing mistakes corrected and a couple of new subsections inserted and abstract stylistically changed a bi

On the Discovery of the GZK Cut-off

The recent claim of the '5 sigma' observation of the Greisen and Zatzepin and Kuzmin cut-off by the HiRes group based on their nine years data is a significant step toward the eventual solution of the one of the most intriguing questions which has been present in physics for more than forty years. However the word 'significance' is used in the mentioned paper in the sense which is not quite obvious. In the present paper we persuade that this claim is a little premature.Comment: 10 page

Light Nuclei solving Auger puzzles. The Cen-A imprint

Ultra High Energy Cosmic Rays (UHECR) map at 60 EeV have been found recently by AUGER group spreading anisotropy signatures in the sky. The result have been interpreted as a manifestation of AGN sources ejecting protons at GZK edges mostly from Super-galactic Plane. The result is surprising due to the absence of much nearer Virgo cluster. Moreover, early GZK cut off in the spectra may be better reconcile with light nuclei (than with protons). In addition a large group (nearly a dozen) of events cluster suspiciously along Cen-A. Finally, proton UHECR composition nature is in sharp disagreement with earlier AUGER claim of a heavy nuclei dominance at 40 EeV. Therefore we interpret here the signals as mostly UHECR light nuclei (He, Be, B, C, O), very possibly mostly the lightest (He,Be) ones, ejected from nearest AGN Cen-A, UHECR smeared by galactic magnetic fields, whose random vertical bending is overlapping with super-galactic arm. The eventual AUGER misunderstanding took place because of such a rare coincidence between the Super Galactic Plane (arm) and the smeared (randomized) signals from Cen-A, bent orthogonally to the Galactic fields. Our derivation verify the consistence of the random smearing angles for He, Be and B, C, O, in reasonable agreement with the AUGER main group events around Cen-A. Only few other rare events are spread elsewhere. The most collimated from Cen-A are the lightest. The most spread the heavier. Consequently Cen-A is the best candidate UHE neutrino tau observable by HEAT and AMIGA as enhanced AUGER array at tens-hundred PeV energy. This model maybe soon tested by new events clustering around the Cen-A and by composition imprint study.Comment: 4 pages, 5 figures

Highest Energy Cosmic Rays and results from the HiRes Experiment

The status of the field of ultrahigh energy cosmic rays is summarized, from the point of view of the latest results of the High Resolution Fly's Eye (HiRes) Experiment. HiRes results are presented, and compared with those of the Akeno Giant Air Shower Array (AGASA), plus the Telescope Array and Pierre Auger experiments. The HiRes measurements of the cosmic ray spectrum, and the observation of the GZK cutoff are presented. HiRes results on composition, searches for anisotropy, measurement of the proton-air total cross section, and shapes of shower profiles are presented.Comment: 31 pages, 18 figures, submitted to Journal of Physics

Program transformations using temporal logic side conditions

This paper describes an approach to program optimisation based on transformations, where temporal logic is used to specify side conditions, and strategies are created which expand the repertoire of transformations and provide a suitable level of abstraction. We demonstrate the power of this approach by developing a set of optimisations using our transformation language and showing how the transformations can be converted into a form which makes it easier to apply them, while maintaining trust in the resulting optimising steps. The approach is illustrated through a transformational case study where we apply several optimisations to a small program