4,643 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
Caranguejos ermitões (Crustacea, Anomura, Diogenidae) de Atol das Rocas, Brasil
Intertidal and shallow infra-littoral samples collected in Rocas Atoll, Rio Grande do Norte State, Brazil, during October 2000, provided material for this study. As a result of this survey, four species of hermit crabs were found and are herein redescribed: Clibanarius antillensis, Calcinus tibicen, Dardanus venosus and Paguristes tortugae. This is the first record of C. tibicen and P. tortugae for the Rocas Atoll.Amostras do entre-marés e infralitoral raso coletadas no Atol das Rocas, Estado do Rio Grande do Norte, Brasil, em outubro de 2000, proporcionaram o material para este estudo. Como resultado dessas coletas, quatro espécies de ermitões foram encontradas e são aqui redescritas: Clibanarius antillensis, Calcinus tibicen, Dardanus venosus e Paguristes tortugae Schmitt, 1933. Este é o primeiro registro de C. tibicen e P. tortugae para o Atol das Rocas
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
Neinei -- The Neutron Imaging Center at the Brazilian Multipurpose Reactor
Neutron imaging is a non-destructive technique for analyzing a wide class of
materials, such as archaeological or structures of industrial materials.
Technological advances, in recent decades, have had a great impact on the
neutron imaging technique, evolving from simple radiographs using films (2D) to
modern tomography systems with digital processing (3D). The Instituto de
Pesquisas Energ\'eticas e Nucleares (IPEN), in Brazil, houses a 5MW research
nuclear reactor, called IEA-R1, where there is a neutron imaging instrument
located at the beam hole 08 (BH08) with in the
sample position. IEA-R1 is over 60 years old and the future of neutron science
in Brazil, including imaging, will be expanded on a new facility called the
Brazilian Multipurpose Reactor (RMB). The RMB will house a suite of instruments
at the Neutron National Laboratory, including the neutron imaging facility
called Neinei. Inspired by recent work, we have calculated the thermal neutron
flux at the sample position, using the Monte Carlo method, in the Neinei and
compared it to the results obtained with the Neutra (PSI), Antares (FRM II),
BT2 (NIST) and DINGO (OPAL) instruments. The results are promising and provide
avenues for future improvements.Comment: 8 pages, 9 figures. Preprin
Development of innovative non-thermal pre-treatments for frozen vegetables: a case of collaborative effort between academic research and food industry
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