1,225 research outputs found
Exploring universal patterns in human home-work commuting from mobile phone data
Home-work commuting has always attracted significant research attention
because of its impact on human mobility. One of the key assumptions in this
domain of study is the universal uniformity of commute times. However, a true
comparison of commute patterns has often been hindered by the intrinsic
differences in data collection methods, which make observation from different
countries potentially biased and unreliable. In the present work, we approach
this problem through the use of mobile phone call detail records (CDRs), which
offers a consistent method for investigating mobility patterns in wholly
different parts of the world. We apply our analysis to a broad range of
datasets, at both the country and city scale. Additionally, we compare these
results with those obtained from vehicle GPS traces in Milan. While different
regions have some unique commute time characteristics, we show that the
home-work time distributions and average values within a single region are
indeed largely independent of commute distance or country (Portugal, Ivory
Coast, and Boston)--despite substantial spatial and infrastructural
differences. Furthermore, a comparative analysis demonstrates that such
distance-independence holds true only if we consider multimodal commute
behaviors--as consistent with previous studies. In car-only (Milan GPS traces)
and car-heavy (Saudi Arabia) commute datasets, we see that commute time is
indeed influenced by commute distance
Hierarchical Space-time Modelling of PM10 Pollution in the Emilia-Romagna Region
In questo lavoro si propone un modello gerarchico per lo studio della distribuzione spazio-temporale dell’inquinamento da PM10 in Emilia-Romagna. L’obiettivo è quello di fornire una prima caratterizzazione della variabilitàspaziale e temporale delle concentrazioni e di misurarne la dipendenza dalle principali grandezze meteorologiche. I risultati mostrano come la variabilitàtemporale sia largamente dominante rispetto all’eterogeneitàspaziale ed alla variabilitànon spiegat
Field Output correction factors of small static field for IBA Razor NanoChamber
The goal of this work is to present results of field output factors (OF)
using an IBA CC003 (Razor NanoChamber) and compared these results with PTW
60019 (MicroDiamond) and IBA Razor Diode. The experimental results for IBA
CC003 were also compared with Monte Carlo (MC) Simulation, using Penelope and
Ulysses programs. In addition, field output correction factors for IBA CC003
were derived with three different methods: 1) using PTW 60019 and IBA Razor as
reference detectors; 2) comparison between MC and experimental measurements;
and 3) using only MC. The beam collimation included in this study were 1)
square field size between 10x10 and 0.5x0.5 cm2 defined by the MLC and jaws and
2) cones of different diameters. For IBA CC003 it was determined the polarity
and ion collection efficiency correction factors in parallel and perpendicular
orientation. The results indicate 1) the variation of polarity effect with the
field size is relevant for the determination of OF using IBA CC003, especially
for parallel orientation; 2) there is no significant variation of the ion
collection efficiency with the field size using IBA CC003 in parallel
orientation; 3) OF differences between IBA CC003 and PTW 60019/IBA Razor and
experimental and MC results increase with decreasing field size. Results on the
field output correction factor indicate 1) using the first and second method,
the factor increase with decreasing field size, which can be related with the
influence of the volume effect and 2) using the third method the factor
decrease with decreasing field size, which can be explained by the perturbation
effect.Comment: 23 pages, 10 figures, 11 table
A comparison between different optimization criteria for tuned mass dampers design
Tuned mass sampers (TMDs) are widely used strategies for vibration control in many engineering applications, so that many TMD optimization criteria have been proposed till now. However, they normally consider only TMD stiffness and damping as design
variables and assume that the tuned mass is a pre-selected value. In this work a more complete approach is proposed and then also TMD mass ratio is optimized. A standard single degree of freedom system is investigated to evaluate TMD protection efficiency in
case of excitation at the support. More precisely, this model is used to develop two different optimizations criteria which minimize the main system displacement or the inertial acceleration. Different environmental conditions described by various char-
acterizations of the input, here modelled by a stationary filtered stochastic process, are considered. Results show that all solutions obtained considering also the mass of the TMD as design variable are more efficient if compared with those obtained without it.
However, in many cases these solutions are inappropriate because the optimal TMD mass is greater than real admissible values in practical technical applications for civil and mechanical engineering. Anyway, one can deduce that there are some interesting indications for applications in some actual contexts. In fact, the results show that there are some ranges of environmental parameters ranges where results attained by the
displacement criterion are compatible with real applications requiring some percent of main system mass. Finally, the present research gives promising indications for complete TMD optimization application in emerging technical contexts, as micro-
mechanical devices and nano resonant beams
Italian Potential Biogas and Biomethane Production from OFMSW
This work is aimed at predicting the potential biogas and biomethane production, using the Organic Fraction of Municipal Solid Waste (OFMSW), in Italy, where 1388 Anaerobic Digestion (AD) plants (power of 7.4 TWh, equal to 640.4 ktep) are nowadays available.
In order to compute the potential biogas and biomethane production in the 20 Italian regions, the data about OFMSW production in 2010-2013 period have been evaluated.
The Italian production of OFMSW, that was 5.2 million tons in 2013 (18% of MSW), could be used inside bioreactors for producing biogas and digestate, that must be aerobically composted into a biofertiliser. In 2013, the Italian potential biogas production from OFMSW was 739 million m3, that is equal to 444 million m3 of biomethane. The highest biogas production from OFMSW was in Lombardy region (143 million m3), having a potential biomethane production of 86 million m3. The highest OFMSW production per inhabitant was in Emilia-Romagna region (142 kg). Yet, if OFMSW was 37% of MSW, the potential biogas and biomethane production should be increased: the biomethane production increase would be 486 million m3, of which the maximum would be in Sicily region.
The biogas produced can be used for generating heat and electricity or upgraded into biomethane, distributed at dedicated stations and useful as biofuel for powering means of transport. This biofuel would replace natural gas, and, therefore, allow a reduction of GreenHouse Gas emissions of 200 g of CO2 kWh-1 (5.5 times lower) and the import of fossil fuels from abroad
Recovery of smell sense loss by mepolizumab in a patient allergic to dermatophagoides and affected by chronic rhinosinusitis with nasal polyps
Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) frequently presents with dysfunction or loss of the
sense of smell, resulting in a signifcant impairment in quality of life. The medical treatments currently available may
improve the olfactory function in patients with CRSwNP, but such an outcome is generally only transitory. We report
the case of a patient with CRSwNP who completely recovered from smell sense loss by treatment with mepolizumab.
Case presentation: The patient was a 62-year-old female who has severe asthma induced by allergy to Dermatophagoides and concomitant CRSwNP. Any treatment for the latter, including oral and injective corticosteroids, was unsuccessful in the loss of smell. Due to the satisfaction of admission criteria to mepolizumab treatment for severe asthma,
treatment was initiated on March 2018, resulting in good clinical control of both asthma and CRSwNP, and particularly
in complete recovery of the smell loss after 4 months of treatment and still persisting.
Conclusion: In this case report, the treatment with mepolizumab in a patient allergic to Dermatophagoides and
afected by CRSwNP was associated with an improvement of anosmia. That fnding may be explained by a reduction
of the nasal obstruction by nasal polyp
Additive Manufacturing using UV Polymerization of Complex Surfaces Generated by Two Main B-Splines
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