Regulation of the burning parameters for energetic materials based on ammonium nitrate and metal nanopowders and nonmetals

The results of study for the influence of metallic and nonmetallic nanopowders on the combustion parameters of mixed energetic materials based on ammonium nitrate are presented and compared with materials, containing micropowders of metals. The catalytic activity rank of the powders is plotted showing their effect on the combustion characteristics of mixed energetic materials

Higher harmonics of azimuthal anisotropy in relativistic heavy ion collisions in HYDJET++ model

The LHC data on azimuthal anisotropy harmonics from PbPb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted in the framework of the HYDJET++ model. The cross-talk of elliptic $v_2$ and triangular $v_3$ flow in the model generates both even and odd harmonics of higher order. Comparison with the experimental data shows that this mechanism is able to reproduce the $p_{\rm T}$ and centrality dependencies of quadrangular flow $v_4$, and also the basic trends for pentagonal $v_5$ and hexagonal $v_6$ flows.Comment: 12 pages including 13 figures as EPS-files; prepared using LaTeX package for publication in the European Physical Journal

Anisotropic flow fluctuations in hydro-inspired freeze-out model for relativistic heavy ion collisions

The LHC data on event-by-event harmonic flow coefficients measured in PbPb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted within the HYDJET++ model. To compare the model results with the experimental data the unfolding procedure is employed. The essentially dynamical origin of the flow fluctuations in hydro-inspired freeze-out approach has been established. It is shown that the simple modification of the model via introducing the distribution over spatial anisotropy parameters permits HYDJET++ to reproduce both elliptic and triangular flow fluctuations and related to it eccentricity fluctuations of the initial state at the LHC energy.Comment: 12 pages including 9 figures as EPS-files; prepared using LaTeX package for publication in the European Physical Journal

Will jets reduce the elliptic flow at LHC, while decays of resonances restore the constituent quark scaling?

Formation and evolution of the elliptic flow pattern in Pb+Pb collisions at sqrt{s}=5.5 ATeV and in Au+Au collisions at sqrt{s}=200 AGeV are analyzed for different hadron species within the framework of HYDJET++ Monte-Carlo model. The model contains both hydrodynamic state and jets, thus allowing for a study of the interplay between the soft and hard processes. It is found that jets are terminating the rise of the elliptic flow with increasing transverse momentum. Since jets are more influential at LHC compared to RHIC, the elliptic flow at LHC should be weaker than that at RHIC. The influence of resonance decays on particle elliptic flow is investigated also. These final state interactions enhance the low-p_T part of the v_2 of pions and light baryons, and work towards the fulfilment of idealized constituent quark scaling.Comment: 8 pages, 9 figures, 3 table

Ignition of boron-containing high-energy materials based on an oxidizer and polymer binder

The use of aluminum borides is a promising direction in the development of modern propellant compositions and aerial vehicles. We present experimental data on the kinetics of oxidation of microscale powders of aluminum, amorphous boron, and the aluminum borides AlB2 and AlB12 in air upon heating at a constant rate of 10°C/min and the results of laser-assisted ignition of high-energy materials that contain these metal powders and are based on ammonium perchlorate, ammonium nitrate, and an inert binder or an energetic combustible binder. We show that the use of the boron-containing powders enables us to lower the onset temperature of oxidation and the temperature of intense oxidation, while increasing their oxidation effectiveness, compared to pure aluminum. The dependences of ignition delay time on the heat flux show that the AlB2 and AlB12 powders are the most effective metal fuel components for solid propellants based on ammonium perchlorate, ammonium nitrate, and an energetic binder: they display the shortest ignition delay time and require the lowest heat input for ignition

Gamma-radiation as a Signature of Ultra Peripheral Ion Collisions at LHC energies

We study the peripheral ion collisions at LHC energies in which a nucleus is excited to the discrete state and then emits $\gamma$-rays. Large nuclear Lorenz factor allows to observe the high energy photons up to a few ten GeV and in the region of angles of a few hundred micro-radians around the beam direction. These photons can be used for tagging the events with particle production in the central rapidity region in the ultra-peripheral collisions. For that it is necessary to have an electromagnetic detector in front of the zero degree calorimeter in the LHC experiments.Comment: 14 pages, 6 Postscript figure