Accretion disk around the rotating Damour-Solodukhin wormhole

A new rotating generalization of the Damour-Solodukhin wormhole (RDSWH), called Kerr-like wormhole, has recently been proposed and investigated by Bueno \textit{et al} for echoes in the gravitational wave signal. We show a novel feature of the RDSWH, viz., that the kinematic properties such as the ISCO\ or marginally stable radius $r_{\text{ms}}$, efficiency $\epsilon$ and the disk potential $V_{\text{eff}}$ are \textit{independent} of $\lambda$ (which means they are identical to their KBH counterparts for any given spin). Differences however appear in the emissivity properties for higher values $0.1<\lambda\leq 1$ (say) and for the extreme spin $a_{\star}=0.998$. The kinematic and emissivity are generic properties as variations of the wormhole mass and the rate of accretion within the model preserve these properties. Specifically, the behavior of the luminosity peak is quite opposite to each other for the two objects, which could be useful from the viewpoint of observations. Apart from this, an estimate of the difference $\Delta_{\lambda}$ in the maxima of flux of radiation $F(r)$ shows non-zero values but is too tiny to be observable at present for $\lambda < 10^{-3}$ permitted by the strong lensing bound. The broad conclusion is that RDSWH\ are experimentally indistinguishable from KBH by accretion characteristics.Comment: 9 pages, 3 tables, 13 figure

Sagnac delay in the Kerr-dS space-time: Implications for Mach's principle

Relativistic twin paradox can have important implications for Mach's principle. It has been recently argued that the behavior of the time asynchrony (different aging of twins) between two flying clocks along closed loops can be attributed to the existence of an absolute spacetime, which makes Mach's principle unfeasible. In this paper, we shall revisit, and support, this argument from a different viewpoint using the Sagnac delay. This is possible since the above time asynchrony is known to be exactly the same as the Sagnac delay between two circumnavigating light rays re-uniting at the orbiting source/receiver. We shall calculate the effect of mass $M$ and cosmological constant $\Lambda$ on the delay in the general case of Kerr-de Sitter spacetime. It follows that, in the independent limits $M\rightarrow 0$, spin $a\rightarrow 0$ and $\Lambda\rightarrow 0$, while the Kerr-dS metric reduces to Minkowski metric, the clocks need not tick in consonance since there will still appear a non-zero observable Sagnac delay. While we do not measure spacetime itself, we do measure the Sagnac effect, which signifies an absolute substantive Minkowski spacetime instead of a void. We shall demonstrate a completely different limiting behavior of Sagnac delay, heretofore unknown, between the case of non-geodesic and geodesic source/observer motion.Comment: 15 pages. arXiv admin note: text overlap with arXiv:1709.0841

Lensing observables: Massless dyonic vis-\`a-vis Ellis wormhole

Stable massless wormholes are theoretically interesting in their own right as well as for astrophysical applications, especially as galactic halo objects. Therefore, the study of gravitational lensing observables for such objects is of importance, and we do here by applying the parametric post-Newtonian method of Keeton and Petters to massless dyonic charged wormholes of the Einstein-Maxwell-Dilaton field theory and to the massless Ellis wormhole of the Einstein minimally coupled scalar field theory. The paper exemplifies how the lensing signatures of two different solutions belonging to two different theories could be qualitatively similar from the observational point of view. Quantitative differences appear depending on the parameter values. Surprisingly, there appears an unexpected divergence in the correction to differential time delay, which seems to call for a review of its original derivation.Comment: 16 pages, 7 figure

Bio resorbability of the modified hydroxyapatite in Tris-HCL buffer

The solubility of carbonated hydroxyapatite powders and granulated carbonated hydroxyapatite produced from the synovial biofluid model solution has been studied. The kinetic characteristics of dissolution were determined. It was found that the solubility of carbonated hydroxyapatite is higher as compared to that of hydroxyapatite. The impact of the organic matrix on the rate of sample dissolution was revealed. For HA-gelatin composites, as the gelatin concentration grows, the dissolution rate becomes greater, and a sample of 6.0 g / L concentration has higher resorbability. The results of the research can be used to study the kinetics of dissolution and the biocompatibility of ceramic materials for medicine, namely for reconstructive surgery, dentistry, and development of drug delivery systems

MEDIATION AS ALTERNATIVE DISPUTE RESOLUTION: LEGAL ANALYSIS, FOREIGN PRACTICE, AND PERSPECTIVES IN RUSSIA

Purposes: The article is devoted to the analysis of legal problems of mediation as an alternative way to resolve disputes. The article examines the Russian and foreign experience in the legal regulation of mediation. Methodology: The use and adaptation of foreign experience in applying the mediation procedure are aimed at increasing the speed of dispute resolution, the level of confidentiality and the ability to maintain partnerships. The authors suggest ways to improve the effectiveness and applicability of this procedure in practice. According to Sungatullina L.A., it seems efficient and promising to use alternative methods for resolving disputes in general and to apply the mediation procedure in particular. Izmailov R.R. He believes that the experience of using mediation techniques has shown its effectiveness in resolving various categories of disputes: labor, family, corporate, business conflicts, as well as in the field of housing relations. Mikhailov A.V. notes that the effectiveness of the mediation process largely depends on the implementation at all stages of the basic principles. Results: The authors conclude that it is advisable to apply mediation to disputes arising from administrative and other public relations. As one of the ways to improve the legislative regulation of mediation, it is proposed to consider the possibility of introducing a notarial certification of mediation agreements. Implications/Applications: Alternative dispute resolution is a set of procedures that facilitate non-judicial dispute resolution. In English practice, it is indicated by the steady turnover of Alternative dispute resolution (hereinafter - ADR). Different non-judicial forms of resolution of a case are referred to ADR in different countries. As a rule, three well-known forms are called: arbitration, mediation, and negotiations. Novelty/Originality: The novelty of this study in classifying the mediation techniques

Strong field lensing by Damour-Solodukhin wormhole

We investigate the strong field lensing observables for the Damour-Solodukhin wormhole and examine how small the values of the deviation parameter $\lambda$ need be for reproducing the observables for the Schwarzschild black hole. While the extremely tiny values of $\lambda$ indicated by the matter accretion or Hawking evaporation are not disputed, it turns out that $\lambda$ could actually assume values considerably higher than those tiny values and still reproduce black hole lensing signatures. The lensing observations thus provide a surprising counterexample to the intuitive expectation that all experiments ought to lead to the mimicking of black holes for the same range of values of $\lambda$.Comment: 6 page

Correction for thermal distortions of laser beams with a flexible mirror. Experimental and numerical investigations

A mathematical model of an adaptive optics system was described in the article. The model included two main components: the model of an adaptive mirror and model of beam propagation under conditions of thermal blooming. Results of numerical simulation of adaptive optics systems were compared with data of laboratory experiments. High reliability of the model was shown