10,994 research outputs found
Parametric study of the interface behavior between two immiscible liquids flowing through a porous medium
When two immiscible liquids that coexist inside a porous medium are drained
through an opening, a complex flow takes place in which the interface between
the liquids moves, tilts and bends. The interface profiles depend on the
physical properties of the liquids and on the velocity at which they are
extracted. If the drainage flow rate, the liquids volume fraction in the
drainage flow and the physical properties of the liquids are known, the
interface angle in the immediate vicinity of the outlet (theta) can be
determined. In this work, we define four nondimensional parameters that rule
the fluid dynamical problem and, by means of a numerical parametric analysis,
an equation to predict theta is developed. The equation is verified through
several numerical assessments in which the parameters are modified
simultaneously and arbitrarily. In addition, the qualitative influence of each
nondimensional parameter on the interface shape is reported.Comment: 7 pages, 12 figure
Laser driven self-assembly of shape-controlled potassium nanoparticles in porous glass
We observe growth of shape-controlled potassium nanoparticles inside a random
network of glass nanopores, exposed to low-power laser radiation. Visible laser
light plays a dual role: it increases the desorption probability of potassium
atoms from the inner glass walls and induces the self-assembly of metastable
metallic nanoparticles along the nanopores. By probing the sample transparency
and the atomic light-induced desorption flux into the vapour phase, the
dynamics of both cluster formation/evaporation and atomic photo-desorption
processes are characterized. Results indicate that laser light not only
increases the number of nanoparticles embedded in the glass matrix but also
influences their structural properties. By properly choosing the laser
frequency and the illumination time, we demonstrate that it is possible to
tailor the nanoparticles'shape distribution. Furthermore, a deep connection
between the macroscopic behaviour of atomic desorption and light-assisted
cluster formation is observed. Our results suggest new perspectives for the
study of atom/surface interaction as well as an effective tool for the
light-controlled reversible growth of nanostructures.Comment: 14 pages,6 figures, http://iopscience.iop.org/1612-202X/11/8/085902
Fine tuning of track impact parameter resolution of the DELPHI detector
The fine tuning of the charged track impact parameter resolution for data and simulation in the DELPHI detector at LEP is described. This tuning was implemented in the software for the tagging of hadrons and has been applied in many precise measurements
Higgs boson couplings: Measurements and theoretical interpretation
This report will review the Higgs boson properties: the mass, the total width
and the couplings to fermions and bosons. The measurements have been performed
with the data collected in 2011 and 2012 at the LHC accelerator at CERN by the
ATLAS and CMS experiments. Theoretical frameworks to search for new physics are
also introduced and discussed.Comment: 67 pages, 23 figure
First results of the two square meters multilayer glass composite mirror design proposed for the Cherenkov Telescope Array developed at INFN
The Cherenkov Telescope Array (CTA) is a future ground-based gamma-ray
astronomy detector that will consist of more than 100 Imaging Atmospheric
Cherenkov Telescopes of different sizes. The total reflective surface of
roughly 10 000 m requires unprecedented technological efforts towards a
cost-efficient production of light-weight and reliable mirror substrates at
high production rate. We report on a new mirror concept proposed for CTA
developed by INFN, which is based on the replication from a spherical convex
mold under low pressure. The mirror substrate is an open structure design made
by thin glass layers at the mirror's front and rear interspaced by steel
cylinders. A first series of nominal size mirrors has been produced, for which
we discuss the optical properties in terms of radius of curvature and focusing
power
Wavelength-shifting light traps for SWGO and other applications
Wavelength-shifting (WLS) materials contain molecules that absorb light and
reemit at longer wavelengths. They can be used for light detection because they
provide a large effective area for low cost and they are able to efficiently
trap and guide light because of total internal reflection processes. We are
currently developing such a WLS detector, considering two main designs: A
single-shift design with one wavelength shift (tile) and a double-shift design
with two wavelength shifts (tile and fiber). As photodetectors we use small
Silicon photomultipliers (SiPMs) with a high photon detection efficiency (PDE)
and single-photon sensitivity. The double-shift layout goes at the expense of
detection efficiency. In this design however, light is channeled to the two
ends of a fiber, thus requiring a reduced photosensitive area compared to the
single-shift layout. We will present the results of our measurements and show
that light traps and SiPMs together represent a promising alternative to PMTs
in case of a non-focused light beam. For the special case of SWGO, the
application of light traps is also motivated by a possible improvement of the
gamma/hadron separation, using a one-chamber tank with an array of
wavelength-shifting light traps instead of a (two-chamber) tank with PMTs.
Besides SWGO, new WLS detectors could also constitute useful and cheap
technology for other experiments and use cases. The contribution summarizes our
motivation and efforts to build a light trap detection module and to
characterize its properties in terms of costs, temporal performance and
detection efficiency.Comment: 8 pages, 9 figures, Presented at the 38th International Cosmic Ray
Conference (ICRC 2023), 202
Emerging work patterns and different territorial contexts: trends for the coworking sector in pandemic recovery
Objectives: The paper aims to explore and unpack the complexity of coworking's
users and supply (i.e. coworking spaces), based on the recent trends caused by Covid19. It is discussed whether and how coworking's environment increases its
diversification in terms of users and the spatial and policy implications linked to this
shift. Methodology: The study embraces a qualitative approach exploring the existing
literature on the emerging dynamics in the field of work, moving from an overview of
recent trends across Europe based on existing international surveys. Results: New
possible scenarios may be based on different forms of proximity, not just in the dense
metropolitan cores, but also in other types of territories, where the population may
decide to selectively re-distribute, and the question will be how to supply all these
areas with effective, efficient and equal opportunities in terms of jobs and services.
The study highlights the diffusion of shared workspaces in different forms: traditional
coworking spaces catering for freelancers and knowledge workers, but also
workspaces in which employees from large organisations (public and private) will
spend part of their working week, hybrid spaces based on peculiar combinations of
locally required services (related to both jobs and care), third-spaces based on some
form of everyday recreational activities, and many others. Limits and implications:
The pandemic is still ongoing and, since the paper focuses on the review of existing
literature and surveys in a changing context, its main limitation is the ability to
collect verifiable and up-to-date data. Originality: The paper's uniqueness lies in the
prefiguration of a range of development directions concerning the relationship
between work practices and collaborative spaces in different territories, exploring
how local and diffused dynamics might be the opportunity for a potential
transformation of work patterns
- …