97,864 research outputs found
Transverse Momentum Distribution and Elliptic Flow of Charged Hadrons in + collisions at GeV using HYDJET++
Recent experimental observations of the charged hadron properties in
collisions at GeV contradict many of the theoretical models of particle
production including two-component Monte Carlo Glauber model. The experimental
results show a small correlation between the charged hadron properties and the
initial geometrical configurations (e.g. body-body, tip-tip etc.) of
collisions. In this article, we have modified the Monte Carlo HYDJET++ model to
study the charged hadron production in collisions at GeV
center-of-mass energy in tip-tip and body-body initial configurations. We have
modified the hard as well as soft production processes to make this model
suitable for collisions. We have calculated the pseudorapidity
distribution, transverse momentum distribution and elliptic flow distribution
of charged hadrons with different control parameters in various geometrical
configurations possible for collision. We find that HYDJET++ model
supports a small correlation between the various properties of charged hadrons
and the initial geometrical configurations of collision. Further, the
results obtained in modified HYDJET++ model regarding and
elliptic flow () suitably matches with the experimental data of
collisions in minimum bias configuration.Comment: 29 pages, 25 figures. Accepted for Publication in EPJ
Influence of extrusion conditions on the colour of millet-legume extrudates using digital imagery
peer-reviewedColour acts as one of the triggers for acceptance of snack foods. Digital imaging in
conjunction with Adobe Photoshop can help identification of variations in the colour of
extruded products. Response surface methodology-based central composite rotatable
designed experiments were conducted to understand the colour components and overall
acceptability (OAA) of extruded snacks made from millet–legume blends, 12–28%
legume, at different moisture content (MC) of 12–24% wet basis (w.b.), extruded at
varying die head temperatures (DHT) from 160–200 °C, barrel temperatures from
100–140 °C and screw speeds of 100–140 rpm. A simple digital camera was used for
capturing the images of the extrudates. An L*a*b* colour model (where L* is the black/
white element, a* is green/red and b* is blue/yellow) was used for colour characterisation
and OAA was determined by a hedonic scale. It was inferred from the analysis of
the resulting statistically valid second order models for the responses that all the colour
components were significantly affected by the amount of legume in the extruder feed
and by the DHT. It was also observed that DHT, synergistically with other processing
parameters, had a significant effect on all the responses. The OAA was highest for the
extrudates with higher L* values. Optimum processing conditions were derived while
the responses adhered to constraints. The responses of the extrudates prepared under
optimum conditions exhibited no significant variation from model predicted values
On the relationship between the modifications to the Raychaudhuri equation and the canonical Hamiltonian structures
The problem of obtaining canonical Hamiltonian structures from the equations
of motion, without any knowledge of the action, is studied in the context of
the spatially flat Friedmann-Robertson-Walker models. Modifications to
Raychaudhuri equation are implemented independently as quadratic and cubic
terms of energy density without introducing additional degrees of freedom.
Depending on their sign, modifications make gravity repulsive above a curvature
scale for matter satisfying strong energy condition, or more attractive than in
the classical theory. Canonical structure of the modified theories is
determined demanding that the total Hamiltonian be a linear combination of
gravity and matter Hamiltonians. In the quadratic repulsive case, the modified
canonical phase space of gravity is a polymerized phase space with canonical
momentum as inverse trigonometric function of Hubble rate; the canonical
Hamiltonian can be identified with the effective Hamiltonian in loop quantum
cosmology. The repulsive cubic modification results in a `generalized
polymerized' canonical phase space. Both of the repulsive modifications are
found to yield singularity avoidance. In contrast, the quadratic and cubic
attractive modifications result in a canonical phase space in which canonical
momentum is non-trigonometric and singularities persist. Our results hint on
connections between repulsive/attractive nature of modifications to gravity
arising from gravitational sector and polymerized/non-polymerized gravitational
phase space.Comment: 22 pages with two new plots. Discussion on uniqueness added, and
possible links with existing models expanded. Periodicity for 'generalized
polymerized' theory and its comparison with standard polymerization
discussed. References added. To appear in CQ
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