787 research outputs found
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
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
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 and
triangular 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 and centrality dependencies of
quadrangular flow , and also the basic trends for pentagonal and
hexagonal flows.Comment: 12 pages including 13 figures as EPS-files; prepared using LaTeX
package for publication in the European Physical Journal
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 -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
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
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