Search results for " fisica"

IEA EBC Annex83 Positive Energy Districts

2021

At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challeng…

Nonlinear black-box models for short-term forecasting of air temperature in the town of Palermo

2011

Weather data are crucial to correctly design buildings and their heating and cooling systems and to assess their energy performances. In the intensely urbanized towns the effect of climatic parameters is further emphasized by the Urban Heat Island (UHI) phenomenon, known as the increase in the air temperature of urban areas, compared to the one measured in the extra-urban areas. The analysis of the heat island needs detailed local climate data which can be collected only by a dedicated weather monitoring system. The Department of Energy and Environmental Researches of the University of Palermo (Italy) has built up a weather monitoring system that works 24 hours per day and makes data availa…

Multimetallic Oxynitrides Nanoparticles for a New Generation of Photocatalysts

2019

A versatile synthetic strategy for the preparation of multimetallic oxynitrides has been designed and here exemplarily discussed considering the preparation of nanoscaled zinc-gallium oxynitrides and zinc-gallium-indium oxynitrides, two important photocatalysts of new generation, which proved to be active in key energy related processes from pollutant decomposition to overall water splitting. The synthesis presented here allows the preparation of small nanoparticles (less than 20 nm in average diameter), well-defined in size and shape, yet highly crystalline and with the highest surface area reported so far (up to 80 m2  g-1 ). X-ray diffraction studies show that the final material is not a…

Extension of landslide susceptibility models: a test in the Platani river basin (Southern Sicily)

2009

Landslide susceptibility assessment in the upper Imera river basin (central Sicilian chain)

2009

Susceptibility assessment for flows landslide in the upper Salso river basin (Sicily)

2009

Vegetation Patterns in the Hyperbolic Klausmeier Model with Secondary Seed Dispersal

2023

This work focuses on the dynamics of vegetation stripes in sloped semi-arid environments in the presence of secondary seed dispersal and inertial effects. To this aim, a hyperbolic generalization of the Klausmeier model that encloses the advective downhill transport of plant biomass is taken into account. Analytical investigations were performed to deduce the wave and Turing instability loci at which oscillatory and stationary vegetation patterns arise, respectively. Additional information on the possibility of predicting a null-migrating behavior was extracted with suitable approximations of the dispersion relation. Numerical simulations were also carried out to corroborate theoretical pre…

Simulation with a Torque Dynamometer of Pollutants Emission from Vehicles Near Urban Cross-Road

2002

Nowadays, the influence of the vehicular traffic on the degradation of urban atmosphere is focused on by researchers belonging to different fields in view of its prime importance for public health. The control of exhaust gases emission is primary in order to keep air pollution below the specified limits of the laws in force. In previous works the “medium car” characterises a country in modelling a pollutant in urban areas. This is the central parameter of a forecasting model proposed by Pignato and LoMastro, of pollutant concentration near urban cross-road with traffic lights in continue queue and platoon flow. The proofs have been carried on two classes of displacement vehicles and four cl…

Ventilation Problems in Heritage Buildings

2007

The control of indoor conditions in heritage buildings, such as castles or museums, is of paramount importance for the proper preservation of the artworks kept in. As heritage buildings are often not equipped with HVAC systems, it is necessary to provide proper interventions and measures with the aim of monitoring and controlling indoor physical parameters. Moreover, another requirement should be achieved in such buildings, that is the maintenance of the safety conditions in presence of visiting people. This work reports the results of a survey carried on a hall of a historical palace, aimed to assess an useful correlation between CO2 concentration and occupancy levels.

Vertex corrections for positive-definite spectral functions of simple metals

2016

We present a systematic study of vertex corrections in the homogeneous electron gas at metallic densities. The vertex diagrams are built using a recently proposed positive-definite diagrammatic expansion for the spectral function. The vertex function not only provides corrections to the well known plasmon and particle-hole scatterings, but also gives rise to new physical processes such as generation of two plasmon excitations or the decay of the one-particle state into a two-particles-one-hole state. By an efficient Monte Carlo momentum integration we are able to show that the additional scattering channels are responsible for the bandwidth reduction observed in photoemission experiments on…