10,765 research outputs found
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
Exact mean field inference in asymmetric kinetic Ising systems
We develop an elementary mean field approach for fully asymmetric kinetic
Ising models, which can be applied to a single instance of the problem. In the
case of the asymmetric SK model this method gives the exact values of the local
magnetizations and the exact relation between equal-time and time-delayed
correlations. It can also be used to solve efficiently the inverse problem,
i.e. determine the couplings and local fields from a set of patterns, also in
cases where the fields and couplings are time-dependent. This approach
generalizes some recent attempts to solve this dynamical inference problem,
which were valid in the limit of weak coupling. It provides the exact solution
to the problem also in strongly coupled problems. This mean field inference can
also be used as an efficient approximate method to infer the couplings and
fields in problems which are not infinite range, for instance in diluted
asymmetric spin glasses.Comment: 10 pages, 7 figure
Shapes of Semiflexible Polymers in Confined Spaces
We investigate the conformations of a semiflexible polymer confined to a
square box. Results of Monte Carlo simulations show the existence of a shape
transition when the persistence length of the polymer becomes comparable to the
dimensions of box. An order parameter is introduced to quantify this behavior.
A simple mean-field model is constructed to study the effect of the shape
transition on the effective persistence length of the polymer.Comment: 8 pages, 20 figure
Static displacements and chemical correlations in alloys
Recent experiments in metallic solid solutions have revealed interesting
correlations between static pair-displacements and the ordering behavior of
these alloys. This paper discusses a simple theoretical model which
successfully explains these observations and which provides a natural framework
for analyzing experimental measurements of pair-displacements and chemical
correlations in solid solutions. The utility and scope of this model is
demonstrated by analyzing results of experiments on and alloys
and results of simulations of and alloys.Comment: 12 page
Self-consistent triaxial de Zeeuw-Carollo Models
We use the usual method of Schwarzschild to construct self-consistent
solutions for the triaxial de Zeeuw & Carollo (1996) models with central
density cusps. ZC96 models are triaxial generalisations of spherical
-models of Dehnen whose densities vary as near the center
and at large radii and hence, possess a central density core for
and cusps for . We consider four triaxial models from
ZC96, two prolate triaxials: with and
1.5, and two oblate triaxials: with and
1.5. We compute 4500 orbits in each model for time periods of .
We find that a large fraction of the orbits in each model are stochastic by
means of their nonzero Liapunov exponents. The stochastic orbits in each model
can sustain regular shapes for or longer, which suggests
that they diffuse slowly through their allowed phase-space. Except for the
oblate triaxial models with , our attempts to construct
self-consistent solutions employing only the regular orbits fail for the
remaining three models. However, the self-consistent solutions are found to
exist for all models when the stochastic and regular orbits are treated in the
same way because the mixing-time, , is shorter than the
integration time, . Moreover, the ``fully-mixed'' solutions can
also be constructed for all models when the stochastic orbits are fully mixed
at 15 lowest energy shells. Thus, we conclude that the self-consistent
solutions exist for our selected prolate and oblate triaxial models with
and 1.5.Comment: 6 Pages, 3 Figures, 2 Tables. Accepted for Publication in A&
- …