232 research outputs found
Correlation methods for the analysis of X-ray polarimetric signals
X-ray polarimetric measurements are based on studying the distribution of the
directions of scattered photons or photoelectrons and on the search of a
sinusoidal modulation with a period of {\pi}. We developed two tools for
investigating these angular distributions based on the correlations between
counts in phase bins separated by fixed phase distances. In one case we use the
correlation between data separated by half of the bin number (one period) which
is expected to give a linear pattern. In the other case, the scatter plot
obtained by shifting by 1/8 of the bin number (1/4 of period) transforms the
sinusoid in a circular pattern whose radius is equal to the amplitude of the
modulation. For unpolarized radiation these plots are reduced to a random point
distribution centred at the mean count level. This new methods provide direct
visual and simple statistical tools for evaluating the quality of polarization
measurements and for estimating the polarization parameters. Furthermore they
are useful for investigating distortions due to systematic effects
Techno-Economic Analysis of Clean Hydrogen Production Plants in Sicily: Comparison of Distributed and Centralized Production
This paper presents an assessment of the levelized cost of clean hydrogen produced in Sicily, a region in Southern Italy particularly rich in renewable energy and where nearly 50% of Italy’s refineries are located, making a comparison between on-site production, that is, near the end users who will use the hydrogen, and centralized production, comparing the costs obtained by employing the two types of electrolyzers already commercially available. In the study for centralized production, the scale factor method was applied on the costs of electrolyzers, and the optimal transport modes were considered based on the distance and amount of hydrogen to be transported. The results obtained indicate higher prices for hydrogen produced locally (from about 7 €/kg to 10 €/kg) and lower prices (from 2.66 €/kg to 5.80 €/kg) for hydrogen produced in centralized plants due to economies of scale and higher conversion efficiencies. How-ever, meeting the demand for clean hydrogen at minimal cost requires hydrogen distribution pipelines to transport it from centralized production sites to users, which currently do not exist in Sicily, as well as a significant amount of renewable energy ranging from 1.4 to 1.7 TWh per year to cover only 16% of refineries’ hydrogen needs
Energy Management of a Hybrid Photovoltaic-Wind System with Battery Storage: A Case Report
This work presents a case report related to the management and the monitoring of a hybrid photovoltaic-wind system with battery energy storage, installed at the administrative offices building of the municipality of Valderice (Italy) within the framework of the Italy-Tunisia ENPI cooperation project Le Développement Durable Dans la Production Energétique Dans le Territoire (DE.DU.ENER.T.). The paper describes the hybrid system and briefly reports the monitoring data for a whole year,
comparing the real production with the expected one and evaluating some performance indexes of the system. The performance indexes are very simple and have been defined only with the purpose of showing the advantages of distributed generation. Then, two different control logics for the battery energy storage systems are compared in order to
define the most suitable management of the local energy resources, in presence of different Time-of-Use electricity tariffs. In particular, the two logics are compared by varying the difference between the electricity prices in peak hours and in off-peak hours and the rate between the electricity consumption of the building and the battery energy
storage’s capacity
Two new catalogs of blazar candidates in the WISE infrared sky
We present two catalogs of radio-loud candidate blazars whose WISE
mid-infrared colors are selected to be consistent with the colors of confirmed
gamma-ray emitting blazars. The first catalog is the improved and expanded
release of the WIBRaLS catalog presented by D'Abrusco et al. (2014): it
includes sources detected in all four WISE filters, spatially cross-matched
with radio source in one of three radio surveys and radio-loud based on their
q22 spectral parameter. WIBRaLS2 includes 9541 sources classified as BL Lacs,
FSRQs or mixed candidates based on their WISE colors. The second catalog,
called KDEBLLACS, based on a new selection technique, contains 5579 candidate
BL Lacs extracted from the population of WISE sources detected in the first
three WISE passbands ([3.4], [4.6] and [12]) only, whose mid-infrared colors
are similar to those of confirmed, gamma-ray BL Lacs. KDBLLACS members area
also required to have a radio counterpart and be radio-loud based on the
parameter q12, defined similarly to q22 used for the WIBRaLS2. We describe the
properties of these catalogs and compare them with the largest samples of
confirmed and candidate blazars in the literature. We crossmatch the two new
catalogs with the most recent catalogs of gamma-ray sources detected by Fermi
LAT instrument. Since spectroscopic observations of candidate blazars from the
first WIBRaLS catalog within the uncertainty regions of gamma-ray unassociated
sources confirmed that ~90% of these candidates are blazars, we anticipate that
these new catalogs will play again an important role in the identification of
the gamma-ray sky.Comment: 20 pages, 7 figures. Accepted for publication in The Astrophysical
Journal Supplement Serie
Studying dark matter with MadDM 3.1: a short user guide
MadDM is an automated numerical tool for the computation of dark-matter
observables for generic new physics models. We announce version 3.1 and
summarize its features. Notably, the code goes beyond the mere cross-section
computation for direct and indirect detection. For instance, it allows the user
to compute the fully differential nuclear recoil rates as well as the energy
spectra of photons, neutrinos and charged cosmic rays for arbitrary
annihilation processes. This short user guide equips researchers with all the
relevant information required to readily perform comprehensive phenomenological
studies of particle dark-matter models.Comment: 17 pages + references; contribution to "Tools for High Energy Physics
and Cosmology" (TOOLS2020), 2-6 Nov. 2020, IP2I Lyon, Franc
Phenomenology of superheavy decaying dark matter from string theory
We study the phenomenology of superheavy decaying dark matter with mass
around GeV which can arise in the low-energy limit of string
compactifications. Generic features of string theory setups (such as high scale
supersymmetry breaking and epochs of early matter domination driven by string
moduli) can accommodate superheavy dark matter with the correct relic
abundance. In addition, stringy instantons induce tiny -parity violating
couplings which make dark matter unstable with a lifetime well above the age of
the Universe. Adopting a model-independent approach, we compute the flux and
spectrum of high-energy gamma rays and neutrinos from three-body decays of
superheavy dark matter and constrain its mass-lifetime plane with current
observations and future experiments. We show that these bounds have only a mild
dependence on the exact nature of neutralino dark matter and its decay
channels. Applying these constraints to an explicit string model sets an upper
bound of on the string coupling, ensuring that the effective
field theory is in the perturbative regime
Anisakid and Raphidascaridid parasites in Trachurus trachurus: infection drivers and possible effects on the host’s condition
This study investigated the distribution of nematode larvae of Anisakidae and Raphidascarididae (genera Anisakis and Hysterothylacium) in Trachurus trachurus (Linnaeus, 1758) in the Ligurian and central-northern Tyrrhenian Seas. The relationship between the number of parasites and the length and weight parameters of the fish was assessed, and the possible effect of the parasites on the condition factor was evaluated. A total of 190 T. trachurus specimens were collected in July 2019. Parasites were found in 70 individuals. A total of 161 visible larvae were collected in the viscera. Morphological analysis revealed the presence of Anisakis spp. in 55 fish and Hysterothylacium spp. in 15 fish, while 5 fish showed coinfection with both genera. The specimens subjected to PCR (n = 67) showed that 85% of the Anisakis larvae analyzed belonged to the species A. pegreffii, while the remaining 15% belonged to hybrids of A. pegreffii-A. simplex (s.s.). A total of 58% (n = 7) of the Hysterothylacium larvae analyzed belonged to the species H. fabri, while 42% belonged to the species H. aduncum. Our results support the hypothesis that infection with these parasites does not affect the condition of the fish host analyzed, and that body size and depth are major drivers in determining infection levels with Anisakid and Raphidascaridid nematodes
Geometrical tools for the analysis of x-ray polarimetric signals
SPIE grants to authors (and their employers) of papers, posters, and presentation recordings published in SPIE Proceedings or SPIE Journals on the SPIE Digital Library (hereinafter "publications") the right to post an author-prepared version or an official version (preferred version) of the publication on an internal or external server controlled exclusively by the author/employer or the entity funding the research, provided that (a) such posting is noncommercial in nature and the publication is made available to users without charge; (b) an appropriate copyright notice and citation appear with the publication; and (c) a link to SPIE's official online version of the publication is provided using the item's DOI.
This authorization does not extend to third-party web sites not owned and maintained by the author/employer such as ResearchGate, Academia.edu, YouTube, etc.X-ray polarimetric measurements are based on the study of distributions of the directions of scattered photons or photoelectrons and the search of a sinusoidal modulation with a period of π. We present a new simple tool based on a scatter plot of the modulation curve in which the counts in each angular bin are reported after a shifting by 1/4 of the period. The sinusoidal pattern is thus transformed in a circular plot whose radius is equal to the amplitude of the modulation, while for a not polarized radiation the scatter plot is reduced to a random point distribution centred at the mean frequency value. The advantage of this tool is that one can easily evaluate the statistical significance of the polarimetric detection and can obtain useful information on the quality of the measurement
VIGIL: a Python tool for automatized probabilistic VolcanIc Gas dIspersion modeLling
Probabilistic volcanic hazard assessment is a standard methodology based on running a deterministic hazard quantification tool multiple times to explore the full range of uncertainty in the input parameters and boundary conditions, in order to probabilistically quantify the variability of outputs accounting for such uncertainties. Nowadays, different volcanic hazards are quantified by means of this approach. Among these, volcanic gas emission is particularly relevant given the threat posed to human health if concentrations and exposure times exceed certain thresholds. There are different types of gas emissions but two main scenarios can be recognized: hot buoyant gas emissions from fumaroles and the ground and dense gas emissions feeding density currents that can occur, e.g., in limnic eruptions.
Simulation tools are available to model the evolution of critical gas concentrations over an area of interest. Moreover, in order to perform probabilistic hazard assessments of volcanic gases, simulations should account for the natural variability associated to aspects such as seasonal and daily wind conditions, localized or diffuse source locations, and gas fluxes.
Here we present VIGIL (automatized probabilistic VolcanIc Gas dIspersion modeLling), a new Python tool designed for managing the entire simulation workflow involved in single and probabilistic applications of gas dispersion modelling. VIGIL is able to manage the whole process from meteorological data processing, needed to run gas dispersion in both the dilute and dense gas flow scenarios, to the post processing of models’ outputs. Two application examples are presented to show some of the modelling capabilities offered by VIGIL
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