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Mechanical performance of auxetic polyurethane foam for antivibration glove applications
In this study the static and dynamic characteristics of conventional open cell
polyurethane (PU), of auxetic (negative Poissonâs ratio) and of iso-density foams
were analysed. The specimens were produced from conventional gray open-cells
polyurethane foam with 30-35 pores/inch and 0.0027 g/cm3 density, by means of
process which has been previously defined by the authors. Poissonâs ratio
measurements were performed under quasi-static conditions using an MTS 858 servohydraulic
test machine and a video image acquisition system. For the auxetic foams
the results suggested similar behaviour to that previously reported in the literature,
with significant increases in stiffness during compressive loading, and a significant
dependence of the Poissonâs ratio on the applied strain. Transmissibility tests,
performed in accordance with the ISO 13753 procedure for antivibration glove
materials, suggested a strong dependence of the transmissibility on the foam
manufacturing parameters. Within the frequency range from 10 to 31.5 Hz the
transmissibility was found to be greater than 1, while it was less than 1 at all
frequencies greater than 31.5 Hz. The transmissibility results were similar to the mean
values for 80 resilient materials tested by Koton et. al., but were higher than the five
best materials (not all polymeric) identified by the same researchers. In this study it
has been suggested that the resilient behaviour of glove isolation materials should also
be evaluated in terms of the indentation characteristics. A simple, linear elastic, Finite
Element simulation was therefore performed, and the indentation results suggested
that auxetic foams offer a significant decrease in compressive stresses with respect to
conventional PU foams
Reclassification of the nearest quasar pair candidate: SDSS J15244+3032 - RXS J15244+3032
We present optical spectroscopy of the nearest quasar pair listed in the 13th
edition of the Veron-Cetty & Veron catalogue, i.e. the two quasars SDSS
J15244+3032 and RXS J15244+3032 (redshift z~0.27, angular separation ~7 arcsec,
and line-of-sight velocity difference ~1900 km/s). This system would be an
optimal candidate to investigate the mutual interaction of the host galaxies
with ground based optical imaging and spectroscopy. However, new optical data
demonstrate that RXS J15244+3032 is indeed a star of spectral type G.
This paper includes data gathered with the Asiago 1.82m telescope (Cima Ekar
Observatory, Asiago, Italy).Comment: 5 pages, 2 figures, 1 table. Accepted for publication in APS
Ultrasound Guidance in Paravertebral Injections of Oxygen-Ozone: Treatment of Low Back Pain
Background: Paravertebral injection of ozone is an established clinical practice for the treatment of Low Back Pain (LBP). The role of Ultrasound Guidance (USG) in mini invasive procedures has become important in many clinical practice thanks to the greater precision this technique can add. As matter of fact, a large volume of ozone in a single administration may have some adverse or side effects. In this study we wanted to verify if the use of USG in Oxygen/ Ozone (O2/O3) infiltrations could allow the administration of a smaller volume of gas mixture, increasing the safety and the comfort of the procedure itself, obtaining however similar or better results in pain decrease.
Methods: We compared two groups of 25 patients affected by LBP, undergoing 10 infiltrations of O2/O3, by using USG (group U) or only anatomical landmarks (group AL). Pain intensity, by calculating Visual Analogical Scale (VAS) difference before and after the treatment, and the discomfort were evaluated in both groups.
Results: The mean of the VAS before the treatment was 6.44 in group U and 6.48 in group AL. The mean of the VAS after the treatment was 2.22 in group U and 3.04 in group AL. The mean of discomfort rate was 2.84 in group U and 5.44 in group AL. The number of patients with unbearable discomfort was 0 in group U and 7 in group AL.
Conclusions: As many other treatment, also paravertebral injections of O2/O3 benefits of the advantages of the US device which makes this treatment safer and more accurate
Energy affordability and the benefits system in Italy
In this paper, we discuss a number of ways to define and measure the affordability of energy consumption, and we examine the emergence of energy poverty in Italy in the period from 1998 to 2011. The paper examines the eligibility criteria for claiming the benefits available to support energy consumption for vulnerable families and it identifies the potential beneficiaries. The study assesses the appropriateness of the eligibility criteria by comparing the population targeted by the policy with the
population actually facing affordability problems. A simulation exercise, using the hypothetical scenario most likely to result in energy benefits made available, shows that, regardless of the affordability index adopted, the provision of state energy benefits has little impact on fuel poverty
A CahnâHilliard system with forward-backward dynamic boundary condition and non-smooth potentials
A system with equation and dynamic boundary condition of CahnâHilliard type is considered.
This system comes from a derivation performed in LiuâWu (Arch. Ration. Mech. Anal., 233:167â247,
2019) via an energetic variational approach. Actually, the related problem can be seen as a transmission
problem for the phase variable in the bulk and the corresponding variable on the boundary. The asymptotic
behavior as the coefficient of the surface diffusion acting on the boundary phase variable goes to 0 is
investigated. By this analysis we obtain a forward-backward dynamic boundary condition at the limit.
We can deal with a general class of potentials having a double-well structure, including the non-smooth
double-obstacle potential. We illustrate that the limit problem is well-posed by also proving a continuous
dependence estimate. Moreover, in the case when the two graphs, in the bulk and on the boundary, exhibit
the same growth, we show that the solution of the limit problem is more regular and we prove an error
estimate for a suitable order of the diffusion parameter
Hemisphere Mixing: a Fully Data-Driven Model of QCD Multijet Backgrounds for LHC Searches
A novel method is proposed here to precisely model the multi-dimensional
features of QCD multi-jet events in hadron collisions. The method relies on the
schematization of high-pT QCD processes as 2->2 reactions made complex by
sub-leading effects. The construction of libraries of hemispheres from
experimental data and the definition of a suitable nearest-neighbor-based
association map allow for the generation of artificial events that reproduce
with surprising accuracy the kinematics of the QCD component of original data,
while remaining insensitive to small signal contaminations. The method is
succinctly described and its performance is tested in the case of the search
for the hh->bbbb process at the LHC.Comment: 4 pages plus header, 1 figure, proceedings of EPS 2017 Venic
Circum-galactic medium in the halo of quasars
The properties of circum-galactic gas in the halo of quasar host galaxies are
investigated analyzing Mg II 2800 and C IV 1540 absorption-line systems along
the line of sight close to quasars. We used optical spectroscopy of closely
aligned pairs of quasars (projected distance 200 kpc, but at very
different redshift) obtained at the VLT and Gran Telescopio Canarias to
investigate the distribution of the absorbing gas for a sample of quasars at
z1. Absorption systems of EW 0.3 associated with the
foreground quasars are revealed up to 200 kpc from the centre of the host
galaxy, showing that the structure of the absorbing gas is patchy with a
covering fraction quickly decreasing beyond 100 kpc. In this contribution we
use optical and near-IR images obtained at VLT to investigate the relations
between the properties of the circum-galactic medium of the host galaxies and
of the large scale galaxy environments of the foreground quasars.Comment: 6 pages, 3 figures, proceedings of the conference "QUASARS at all
cosmic epochs", accepted for publication on Frontiers in Astronomy and Space
Scienc
HST Observations of the Optical Jets of PKS 0521-365, 3C371, and PKS 2201+044
HST observations have led to the discovery of the optical counterpart of the
radio jet of PKS 2201+044, and to a detailed analysis of the optical jets of
PKS 0521-365 and 3C371. At HST spatial resolution these jets are well resolved,
displaying knotty morphologies. When compared with radio maps of appropriate
resolution, a clear one-to-one correspondence between optical and radio
structures is found, showing that all detected optical structures are indeed
related to the radio synchrotron emission. Photometry of the brightest knots
shows that the radio-to-optical spectral index and the derived intensity of the
equipartition magnetic field are approximately constant along the jet. Thus,
present observations suggest that the electron energy distribution does not
change significantly all along the jet.Comment: Accepted for publications on the Astrphysical Journal. Contains 14
pages and 5 figure
Joint parental school choice: exploring the influence of individual preferences of husbands and wives
The objective of this paper is to study school choice as a deliberate joint parental decision. This decision is affected by the underlying preferences of the husband and wife. We use survey data from a sample of parents in the metropolitan area of Bilbao (Spain) to estimate a bargaining discrete choice model. The collected data set contains hypothetical school choices gathered in the form of a typical discrete choice experiment (stated preferences) and the actual school choice (revealed preferences). Stated preference data are obtained separately for husbands and wives, but the revealed preference choice is taken jointly. Our findings show, firstly, that the husband's and wife's stated preferences regarding school choice do not differ markedly. Secondly, the results obtained for the revealed preferences deviate from the stated preferences for some school characteristics. Finally, we find that neither the husband's nor the wife's preferences prevail in the actual joint school choice decision
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