4,071 research outputs found
Isospin Constraints on the Parametric Coupling Model for Nuclear Matter
We make use of isospin constraints to study the parametric coupling model and
the properties of asymmetric nuclear matter. Besides the usual constraints for
nuclear matter - effective nucleon mass and the incompressibility at saturation
density - and the neutron star constraints - maximum mass and radius - we have
studied the properties related with the symmetry energy. These properties have
constrained to a small range the parameters of the model. We have applied our
results to study the thermodynamic instabilities in the liquid-gas phase
transition as well as the neutron star configurations.Comment: 11 pages, 10 figure
Compact stars within an asy-soft quark-meson-coupling model
We investigate compact star properties within the quark meson coupling model
(QMC) with a soft symmetry energy density dependence at large densities. In
particular, the hyperon content and the mass/radius curves for the families of
stars obtained within the model are discussed. The hyperon-meson couplings are
chosen according to experimental values of the hyperon nuclear matter
potentials, and possible uncertainties are considered. It is shown that a
softer symmetry energy gives rise to stars with less hyperons, smaller radii
and larger masses. Hyperon-meson couplings may also have a strong effect on the
mass of the star.Comment: 7 pages, revtex, accepted in Phys. Rev.
Scalaroca stars: coupled scalar-Proca solitons
We construct and explore the physical properties of \textit{scalaroca stars}:
spherically symmetric solitonic solutions made of a complex scalar field
and a complex Proca field . We restrict our attention to configurations
in which both fields are in the fundamental state and possess an equal mass,
focusing on the cases when () the scalar and Proca fields are
(non--linearly) super--imposed and do not interact with each other; and ()
the scalar and Proca fields interact through the term . The solutions are found numerically for the non--interacting case
() as well as for both signs of the interaction coupling constant
. While pure ( single--field) Proca/scalar boson stars are the
most/least massive for weakly--interacting fields, one can obtain more massive
solutions for a sufficiently strong interaction. Besides, in the latter case,
solutions can be either in a synchronized state -- in which both fields have
the same frequency -- or in a non--synchronized state. In addition, we observe
that the coupling between the two fields allows solitonic solutions with a real
scalar field. We further comment on the possibility of spontaneous
scalarization and vectorization of the interacting solitonic solution.Comment: 21 pages, 13 figures, this project was started before the recently
published work ArXiv:2304.0801
COMFORT SEAT MODULE - FIRST CLASS COMFORT FOR ALL
The Comfort Seat Module (CSM) is a project developed in the scope of the EDAM focus area of
the MIT – Portugal program, within the Product Design and Development course.
The team members involved in the project come from several Engineering backgrounds and
includes research students and engineering professionals, from different geographical origins.
In this project the team had the purpose of designing and developing a solution, from idea
into concept and then onto a valid product that could potentially be produced and even
marketed. In parallel, the objective was to train the product development competences and
team’s working skills as much as possible, considering the physical distance between the
team members.info:eu-repo/semantics/publishedVersio
Study on thermosonication and ultraviolet radiation processes as an alternative to blanching for some fruits and vegetables
The impacts of ultraviolet-C radiation, blanching
by heat, and combination of heat/ultrasounds (thermosonication)
were studied for Listeria innocua (inoculated) in red bell
peppers, total mesophiles in strawberries and total coliforms
in watercress, in the temperature range 50–65 °C. Quality
attributes such as colour and firmness were studied for all
products, and total anthocyanins content was additionally
determined for strawberries. Results showed that ultraviolet-
C radiation was the least effective treatment in terms of
microbial load reduction and was equivalent to a simple
water washing. Log reductions were 1.05±0.52 for L.
innocua, 0.53±0.25 for total coliforms and 0.26±0.18 for
total mesophiles. This treatment had the lowest impact on the
quality parameters analysed. Thermosonication treatment
was similar to heat blanching for all microorganism/product
tested, excepted for total coliforms in watercress at 65 °C, in
which thermosonication had a higher effect (p<0.05). Heat
blanching at 65 °C allowed 7.43±0.12 log-cycles reduction,
while loads were diminished by 8.24±0.13 log-cycles if
thermosonication at the same temperature was applied.
Thermosonication also allowed better quality retention, when
compared to heat blanching at the same temperatures. The
impact of thermosonication on microbial load reductions was
statistically significant and thermosonicated samples retained
quality attributes better than heat blanched ones at the same
temperatures (p<0.05). Hence, it can be concluded that
thermosonication is a promising process and may be a
favourable alternative to the conventional thermal treatments
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