521 research outputs found
Assessment of the energetic potential by hazelnuts pruning in Viterbo’s area
In this work the amount of biomass available by the hazelnuts pruning in the province of Viterbo was investigated. At present, the pruning's residues are destroyed by farmers directly in the field, at the end of the pruning; in this way a large quantity of biomass, represented by hazelnut's prunings, is lost; the residues obtained from the hazelnut's pruning, are an important source of biomass that could be used for thermal energy production. The aim of this work is to realize a map with the estimated energy potential from hazelnut pruning biomass, in the province of Viterbo. In the first phase the amount of biomass obtained from a hectare of hazelnut's cultivationwas estimated:sampling were carried out in some municipalities of Viterbo while hazelnut pruning was taking place, from January to March.In the field, biomass was weighed and some pieces of wood were collected for laboratory analysis; in particular humidity of biomass, low calorific value, ashand the content of carbon (C), hydrogen (H) and nitrogen (N) were determined. In the calculation of the biomass were considered the age of the plants and the number of plants per hectare. The results show that the amount of biomass obtained from pruning of hazelnuts varies with the age of plants, but even more so by the number of plants per hectare. The average value of biomass obtained from pruning of a hectare of land is just under 0,9 t. Knowing the net calorific value of the hazelnut wood and the number of hectares cultivated for each municipality, a map of thermal potential energy has been realized
The heat stress for workers employed in a dairy farm
The Italian dairy production is characterized by high heterogeneity. The typology quantitatively more important (80% of national production) is represented by cow’s milk cheeses (Grana Padano cheese, string cheese, Parmesan cheese, etc.), while the cheese from buffalo’s milk (especially string cheese such as mozzarella) and cheese from sheep and goats represents respectively 4% and 8% of the national dairy production, and are linked to specific regional contexts. Some phases of the cycle of milk processing occur at certain temperatures that are not comfortable for the workers also in relation to possible problems due to thermal shock. The aim of this study was to evaluate the risk of heat stress on workers operating in a dairy for processing of buffalo milk. The research was conducted at a dairy farm located in the province of Viterbo, Italy, during the spring-summer period. To carry out the research were detected major climatic parameters (air temperature, relative humidity, mean radiant temperature, air velocity) and the main parameters of the individual operators (clothing thermal insulation and the energy expenditure required from the work done by employees). Subsequently, main indices of heat stress assessment provided by the main technical standards were calculated. In particular have been calculated predicted mean vote and predicted percentage of dissatisfied in moderate thermal environments (environments in which the objective, in the design and management phases, is to achieve the thermal comfort), provided by the UNI EN ISO 7730 and the wet bulb globe temperature in severe hot environments (environments in which you must protect the health of workers) required by UNI EN ISO 27243. The results show some phases of risk from heat stress especially during times of test in which the internal air temperature exceeds the threshold of 30°C and possible solutions to improve the safety of the operators
Electrophysiological and behavioral activity of (E)-2-hexenal in the granary weevil and its application in food packaging.
The purpose of this work was to develop a biodegradable carrier material to control insect pests in cereal products. To this aim, (E)-2-hexenal was used, being a natural compound with antimicrobial activity that is also commonly adopted as a flavoring agent. Three coating layers of polycaprolactone (PCL) were spread onto the internal side of a paperboard carton, the first being the active coating containing (E)-2-hexenal. The antennal sensitivity of Sitophilus granarius to a broad range of doses of (E)-2-hexenal was first demonstrated. Next, the ability of different concentrations of this compound to disrupt the orientation of adult S. granarius beetles to odors of intact wheat kernels was established in a two-choice pitfall bioassay. In addition, invasion tests were carried out over an 8-week period to highlight the effects of the biobased repellent packaging and their potential persistence. The results demonstrated that during the entire monitoring period, the percentage of S. granarius adults found in cartons coated with (E)-2-hexenal-loaded multilayer PCL was about 10 % of the total number of insects used in the bioassay, very low compared with the respective control samples, thus assessing both the effectiveness and persistence of the repellent system developed. Although the infestation level of treated packages was reduced relative to the infestation levels in the controls, any infestation of food packages is unacceptable to consumers, so further tests are required to determine whether infestation can be completely prevented using (E)-2-hexenal
Social networks and labour productivity in Europe: An empirical investigation
This paper uses firm-level data recorded in the AMADEUS database to
investigate the distribution of labour productivity in different European
countries. We find that the upper tail of the empirical productivity
distributions follows a decaying power-law, whose exponent is obtained
by a semi-parametric estimation technique recently developed by Clementi et al.
(2006). The emergence of "fat tails" in productivity distribution has already
been detected in Di Matteo et al. (2005) and explained by means of a model of
social network. Here we show that this model is tested on a broader sample of
countries having different patterns of social network structure. These
different social attitudes, measured using a social capital indicator, reflect
in the power-law exponent estimates, verifying in this way the existence of
linkages among firms' productivity performance and social network.Comment: LaTeX2e; 18 pages with 3 figures; Journal of Economic Interaction and
Coordination, in pres
Characterization of SABRE crystal NaI-33 with direct underground counting
Ultra-pure NaI(Tl) crystals are the key element for a model-independent
verification of the long standing DAMA result and a powerful means to search
for the annual modulation signature of dark matter interactions. The SABRE
collaboration has been developing cutting-edge techniques for the reduction of
intrinsic backgrounds over several years. In this paper we report the first
characterization of a 3.4 kg crystal, named NaI-33, performed in an underground
passive shielding setup at LNGS. NaI-33 has a record low K contamination
of 4.30.2 ppb as determined by mass spectrometry. We measured a light
yield of 11.10.2 photoelectrons/keV and an energy resolution of 13.2%
(FWHM/E) at 59.5 keV. We evaluated the activities of Ra and Th
inside the crystal to be Bq/kg and Bq/kg,
respectively, which would indicate a contamination from U and
Th at part-per-trillion level. We measured an activity of 0.510.02
mBq/kg due to Pb out of equilibrium and a quenching factor of
0.630.01 at 5304 keV. We illustrate the analyses techniques developed to
reject electronic noise in the lower part of the energy spectrum. A cut-based
strategy and a multivariate approach indicated a rate, attributed to the
intrinsic radioactivity of the crystal, of 1 count/day/kg/keV in the
[5-20] keV region
Characterization of SABRE crystal NaI-33 with direct underground counting
Published online: 09 April 2021Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low ³⁹K contamination of 4.3 ± 0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1 ± 0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of ²²⁶Ra and ²²⁸Th inside the crystal to be 5.9±0.6 μBq/kg and 1.6±0.3 μBq/kg, respectively, which would indicate a contamination from ²³⁸U and ²³²Th at part-per-trillion level. We measured an activity of 0.51 ± 0.02 mBq/kg due to ²¹⁰Pb out of equilibrium and a α quenching factor of 0.63 ± 0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of ∼1 count/day/kg/keV in the [5–20] keV region.M. Antonello ... I. Bolognino ... A. G. Williams ... et al
Borexino's search for low-energy neutrinos associated with gravitational wave events from GWTC-3 database
The search for neutrino events in correlation with gravitational wave (GW)
events for three observing runs (O1, O2 and O3) from 09/2015 to 03/2020 has
been performed using the Borexino data-set of the same period. We have searched
for signals of neutrino-electron scattering with visible energies above 250 keV
within a time window of 1000 s centered at the detection moment of a particular
GW event. The search was done with three visible energy thresholds of 0.25, 0.8
and 3.0 MeV.Two types of incoming neutrino spectra were considered: the
mono-energetic line and the spectrum expected from supernovae. The same spectra
were considered for electron antineutrinos detected through inverse beta-decay
(IBD) reaction. GW candidates originated by merging binaries of black holes
(BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were
analysed separately. Additionally, the subset of most intensive BHBH mergers at
closer distances and with larger radiative mass than the rest was considered.
In total, follow-ups of 74 out of 93 gravitational waves reported in the GWTC-3
catalog were analyzed and no statistically significant excess over the
background was observed. As a result, the strongest upper limits on
GW-associated neutrino and antineutrino fluences for all flavors (\nu_e,
\nu_\mu, \nu_\tau) have been obtained in the (0.5 - 5.0) MeV neutrino energy
range.Comment: 13 pages, 8 figure
Short-Run Regional Forecasts: Spatial Models Through Varying Cross-Sectional and Temporal Dimensions
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