168 research outputs found
Capillary filling using Lattice Boltzmann Equations: the case of multi-phase flows
We present a systematic study of capillary filling for multi-phase flows by
using mesoscopic lattice Boltzmann models describing a diffusive interface
moving at a given contact angle with respect to the walls. We compare the
numerical results at changing the density ratio between liquid and gas phases
and the ratio between the typical size of the capillary and the interface
width. It is shown that numerical results yield quantitative agreement with the
Washburn law when both ratios are large, i.e. as the hydrodynamic limit of a
infinitely thin interface is approached. We also show that in the initial stage
of the filling process, transient behaviour induced by inertial effects and
``vena contracta'' mechanisms, may induce significant departure from the
Washburn law. Both effects are under control in our lattice Boltzmann equation
and in good agreement with the phenomenology of capillary filling
Neuromarketing empirical approaches and food choice: A systematic review
Consumers' food choices are often driven by reasons of which consumers are not fully aware. Decision-making
about food is influenced by a complex set of emotions, feelings, attitudes, and values that are impossible to assess
simply by asking consumers their opinions. Indeed, traditional techniques, such as self-reports or interviews,
mainly allow the measurement of conscious and rational reactions to a product or advertising. Recently, there
has been a rapidly growing interest in the multidisciplinary field of “neuromarketing,” which takes advantage of
neuroscientific techniques to study consumer behavior.
This discipline applies neuroscientific methods and tools that allow the measurement of consumers' emotional
and spontaneous reactions in a more objective and observable way. The aim of this paper is (a) to describe
neuromarketing's underlying assumptions, techniques, and the advantages of this perspective, examining the
scientific literature on the use of neuromarketing in food studies; and (b) to suggest best practices to apply this
novel approach in the food marketing domain, with a specific focus on non-invasive methods.
Finally, although the perception of nutritional elements has already been explored, the health content of
labels, the presence of additives, and the evaluation of the information conveyed by food packaging remain other
possible elements of interest in future food neuromarketing research
Capillary filling with wall corrugations] Capillary filling in microchannels with wall corrugations: A comparative study of the Concus-Finn criterion by continuum, kinetic and atomistic approaches
We study the impact of wall corrugations in microchannels on the process of
capillary filling by means of three broadly used methods - Computational Fluid
Dynamics (CFD), Lattice-Boltzmann Equations (LBE) and Molecular Dynamics (MD).
The numerical results of these approaches are compared and tested against the
Concus-Finn (CF) criterion, which predicts pinning of the contact line at
rectangular ridges perpendicular to flow for contact angles theta > 45. While
for theta = 30, theta = 40 (no flow) and theta = 60 (flow) all methods are
found to produce data consistent with the CF criterion, at theta = 50 the
numerical experiments provide different results. Whilst pinning of the liquid
front is observed both in the LB and CFD simulations, MD simulations show that
molecular fluctuations allow front propagation even above the critical value
predicted by the deterministic CF criterion, thereby introducing a sensitivity
to the obstacle heigth.Comment: 25 pages, 8 figures, Langmuir in pres
Evidence of thin-film precursors formation in hydrokinetic and atomistic simulations of nano-channel capillary filling
We present hydrokinetic Lattice Boltzmann and Molecular Dynamics simulations
of capillary filling of high-wetting fluids in nano-channels, which provide
clear evidence of the formation of thin precursor films, moving ahead of the
main capillary front. The dynamics of the precursor films is found to obey the
Lucas-Washburn law as the main capillary front, z2(t) proportional to t,
although with a larger prefactor, which we find to take the same value for both
geometries under inspection. Both hydrokinetic and Molecular Dynamics
approaches indicate a precursor film thickness of the order of one tenth of the
capillary diameter. The quantitative agreement between the hydrokinetic and
atomistic methods indicates that the formation and propagation of thin
precursors can be handled at a mesoscopic/hydrokinetic level, thereby opening
the possibility of using hydrokinetic methods to space-time scales and complex
geometries of direct experimental relevance.Comment: 11 pages, 6 figures. submitted to PR
Clinical‐epidemiological aspects of the Monkeypox 2022 epidemic: a multicenter study by the Italian SIDeMaST Group of Sexually Transmitted, Infectious and Tropical Diseases
Dear Editor,In spring 2022, an increase of monkeypox (mpox) cases was reported in Europe. Mpox is a zoonotic virus of the Poxviridae family, is endemic in the Congo Basin and just few cases outside Africa were reported before 2022. Its cutaneous presentation is similar to smallpox, usually preceded by a prodromal phase of fever, lymphadenopathy, headache and asthenia. Infection can occur through various means, including skin-to-skin contact, respiratory droplets or contact with fomites. The new outbreak is unique due to the increased human-to-human transmission, without an animal reservoir, particularly among men who have sex with men (MSM). As of February 13, 2023, 85.860 confirmed cases have been reported in 110 countries
Front pinning in capillary filling of chemically coated channels
The dynamics of capillary filling in the presence of chemically coated
heterogeneous boundaries is investigated, both theoretically and numerically.
In particular, by mapping the equations of front motion onto the dynamics of a
dissipative driven oscillator, an analytical criterion for front pinning is
derived, under the condition of diluteness of the coating spots. The criterion
is tested against two dimensional Lattice Boltzmann simulations, and found to
provide satisfactory agreement as long as the width of the front interface
remains much thinner than the typical heterogeneity scale of the chemical
coating.Comment: 7 pages, 4 figures, submitted to Physical Review
PsoBioVax: A multicentric Italian case–control study of the immunological response to anti‐SARS‐CoV‐2 vaccine among psoriatic patients under biological therapy
Dear Editor, The role of vaccination has been crucial in limiting COVID-19.1 The efficacy of vaccines among patients with immunemediated inflammatory disease has been investigated showing promising results.2 Patients with psoriasis under biological treatment had a valid response to the COVID-19 vaccine
New MACRO results on atmospheric neutrino oscillations
The final results of the MACRO experiment on atmospheric neutrino
oscillations are presented and discussed. The data concern different event
topologies with average neutrino energies of ~3 and ~50 GeV. Multiple Coulomb
Scattering of the high energy muons in absorbers was used to estimate the
neutrino energy of each event. The angular distributions, the L/E_nu
distribution, the particle ratios and the absolute fluxes all favour nu_mu -->
nu_tau oscillations with maximal mixing and Delta m^2 =0.0023 eV^2. A
discussion is made on the Monte Carlos used for the atmospheric neutrino flux.
Some results on neutrino astrophysics are also briefly discussed.Comment: Invited Paper at the NANP03 Int. Conf., Dubna, 200
Hydrokinetic simulations of nanoscopic precursor films in rough channels
We report on simulations of capillary filling of high-wetting fluids in
nano-channels with and without obstacles. We use atomistic (molecular dynamics)
and hydrokinetic (lattice-Boltzmann) approaches which point out clear evidence
of the formation of thin precursor films, moving ahead of the main capillary
front. The dynamics of the precursor films is found to obey a square-root law
as the main capillary front, z^2(t) ~ t, although with a larger prefactor,
which we find to take the same value for the different geometries (2D-3D) under
inspection. The two methods show a quantitative agreement which indicates that
the formation and propagation of thin precursors can be handled at a
mesoscopic/hydrokinetic level. This can be considered as a validation of the
Lattice-Boltzmann (LB) method and opens the possibility of using hydrokinetic
methods to explore space-time scales and complex geometries of direct
experimental relevance. Then, LB approach is used to study the fluid behaviour
in a nano-channel when the precursor film encounters a square obstacle. A
complete parametric analysis is performed which suggests that thin-film
precursors may have an important influence on the efficiency of
nanochannel-coating strategies.Comment: 16 pages, 8 figures; To be published on JSTAT: Journal of statistical
mechanics: Theory and experiment
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