32 research outputs found
Water jet rebounds on hydrophobic surfaces : a first step to jet micro-fluidics
When a water jet impinges upon a solid surface it produces a so called
hydraulic jump that everyone can observe in the sink of its kitchen. It is
characterized by a thin liquid sheet bounded by a circular rise of the surface
due to capillary and gravitational forces. In this phenomenon, the impact
induces a geometrical transition, from the cylindrical one of the jet to the
bi-dimensional one of the film. A true jet rebound on a solid surface, for
which the cylindrical geometry is preserved, has never been yet observed. Here
we experimentally demonstrate that a water jet can impact a solid surface
without being destabilized. Depending on the incident angle of the impinging
jet, its velocity and the degree of hydrophobicity of the substrate, the jet
can i) bounce on the surface with a fixed reflected angle, ii) land on it and
give rise to a supported jet or iii) be destabilized, emitting drops. Capillary
forces are predominant at the sub-millimetric jet scale considered in this
work, along with the hydrophobic nature of the substrate. The results presented
in this letter raise the fundamental problem of knowing why such capillary
hydraulic jump gives rise to this unexpected jet rebound phenomenon. This study
furthermore offers new and promising possibilities to handle little quantity of
water through "jet micro-fluidics
Does psychache mediate the relationship between general distress and suicide ideation?
This study evaluated whether psychache (i.e., mental pain) mediates the association between general distress, assessed as the frequency and the intensity of psychological symptoms in the previous week, and suicide ideation in community adults. For a sample of 202 adults, psychache fully mediated the relationship between suicide ideation and the frequency of psychological symptoms, and partially mediated the relationship between suicide ideation and the intensity of psychological symptoms. As such, mental pain fully or partially explains the process linking the frequency and the intensity of general distress to suicide ideation and, thus, mental pain is a target for potential intervention
A emissão de feedback durante uma aula de grupo de ginásios da cidade de Setúbal
info:eu-repo/semantics/publishedVersio
Measurement of the Atmospheric Muon Charge Ratio at TeV Energies with MINOS
The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray
muon data since the beginning of August, 2003 at a depth of 2070
meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA.
The data with both forward and reversed magnetic field running configurations
were combined to minimize systematic errors in the determination of the
underground muon charge ratio. When averaged, two independent analyses find the
charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.).
Using the map of the Soudan rock overburden, the muon momenta as measured
underground were projected to the corresponding values at the surface in the
energy range 1-7 TeV. Within this range of energies at the surface, the MINOS
data are consistent with the charge ratio being energy independent at the two
standard deviation level. When the MINOS results are compared with measurements
at lower energies, a clear rise in the charge ratio in the energy range 0.3 --
1.0 TeV is apparent. A qualitative model shows that the rise is consistent with
an increasing contribution of kaon decays to the muon charge ratio.Comment: 16 pages, 17 figure
Measurement of neutrino velocity with the MINOS detectors and NuMI neutrino beam
The velocity of a ~3 GeV neutrino beam is measured by comparing detection times at the near and far detectors of the MINOS experiment, separated by 734 km. A total of 473 far detector neutrino events was used to measure (v-c)/c=5.12.910-5 (at 68% C.L.). By correlating the measured energies of 258 charged-current neutrino events to their arrival times at the far detector, a limit is imposed on the neutrino mass of mnu<50 MeV/c2 (99% C.L.)
First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector
The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nuµ and [overline nu ]µ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nuµ and [overline nu ]µ interactions are separated. The ratio of [overline nu ]µ to nuµ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nuµ and [overline nu ]µ
Thermorheological and textural behaviour of gluten-free gels obtained from chestnut and rice flours
Nowadays, as celiac disease is becoming more
common the consumers’ demand for gluten-free products
with high nutritional and taste quality is increasing. This
work deals with the study of the impact of four novelty
gluten-free sources: chestnut flour (Cf), whole rice flour
(Rw), Carolino rice flour (Rc) and Agulha rice flour (Ra).
Textural, thermorheological and stability performance of
gluten-free gels using different experimental techniques
were evaluated. Mixed gels were also produced for comparison.
Texture parameters were determined from the texture
profile analysis using a texturometer. Thermorheological
oscillatory measurements were conducted in a stresscontrolled
rheometer in order to clarify the kinetics of gel
formation and to characterise the structure of the matured
gels. The stability of the gels was evaluated using transmittance
profiling of the gels under gravitational fields
(LUMiSizer®). Texture studies suggested that gels from mixtures of chestnut flour at 30 % and rice flour at 20 %
showed the right texture to develop gel-based new desserts.
Rheological results showed that the thermal profiles on
heating of Cf gels were similar to those obtained for Rw
and Ra, whereas Rc gels exhibited a particular pattern. Once
the final gelatinisation temperature was achieved, no significant
differences on the viscoelastic properties were noticed
for all the tested gels. Stability tests showed that gels with
Rc should present an industrial advantage over the other
assayed formulations, since the stability of these gels is of
the order of four times larger