Numerical weather predictions (NWP) play a fundamental role in air quality management. The transport and deposition of all the pollutants (natural and/or anthropogenic) present in the atmosphere are strongly influenced by meteorological conditions such as, for example, precipitation and winds. Furthermore, the presence of particulate matter in the atmosphere favors the physical processes of nucleation of the hydrometeors, thus increasing the risk of even extreme weather events. In this framework of reference, the present work aimed to improve the quality of weather forecasts related to extreme events through the optimization of the weather research and forecasting (WRF) model. For this purpose, the simulation results obtained using the WRF model, where physical parametrizations of the cumulus scheme can be optimized, are reported. As a case study, we considered the extreme meteorological event recorded on 25 November 2016, which affected the whole territory of Sicily and, in particular, the area of Sciacca (Agrigento). In order, to evaluate the performance of the proposed approach, we compared the WRF model outputs with data obtained by a network of radar and weather stations. The comparison was performed through statistical methods on the basis of a “contingency table”, which allowed for ascertaining the best suited physical parametrizations able to reproduce this event.
Abstract. This work reports the results of an experimental study where laser techniques are applied to acoustically levitated droplets of trehalose aqueous solutions in order to perform spectroscopic analyses as a function of concentration and to test the theoretical diameter law. The study of such systems is important in order to better understand the behaviour of trehalose-synthesizing extremophiles that live in extreme environments. In particular, it will be shown how acoustic levitation, combined with optical spectroscopic instruments allows to explore a wide concentration range and to test the validity of the diameter law as a function of levitation lag time, i.e. the D 2 vs t law. On this purpose a direct diameter monitoring by a video camera and a laser pointer was first performed; then the diameter was also evaluated by an indirect measure through an OH/CH band area ratio analysis of collected Raman and Infrared spectra. It clearly emerges that D 2 vs t follows a linear trend for about 20 minutes, reaching then a plateau at longer time. This result shows how trehalose is able to avoid total water evaporation, this property being essential for the surviving of organisms under extreme environmental conditions.
During last 20 years, Sicily has been affected by an increasing sequence of extreme weather events that have produced, besides huge damages to both environment and territory, the death of hundreds of people together with the evacuation of thousands of residents, which have permanently lost their houses. The aim of this paper is to describe the Weather Research and Forecasting Model (WRF) and to report findings obtained, through this model, in a relevant case study. On purpose a WRF Local Area Model (LAM) has been used to re-analyze the heavy rainfall occurred during the night of October 10th, 2015 in Sicily. The re-analysis of this case study, shows how a LAM, suitably configured for the complex orography of Sicily, is able to forecast this kind of extreme weather events. This study clearly shows how forecasts obtained using this kind of model can be very useful to reduce the hydrogeological impact of extreme events on the environment and on territory.
Most of devices used for controlling a system are composed of four main parts: a sensor that "senses" the system, generally converting a physical quantity in electric signal, a control electronics that analyses this signal, an actuator that re-converts the electric signal to the physical quantity and finally a power supply unit that provides the general supplying of the device. The global effect is the control of the physical quantity through a feedback chain. In particular, for mechanical systems, the electronics and the power supply units make the device complex and expensive, increasing in many cases the time response. The device presented in this work, conceived for controlling a mechanical quantity (force, pressure, deformation, etc.), utilizes piezoelectric for both the actuator and sensor parts. The electrical signal generated by the sensor is directly supplied to the piezoelectric actuator without any additional intermediate electronics, realizing a fully self-supplied sensing-actuating device. Without control electronics and power supply unit the device becomes inexpensive, simple and fast no matter the distance in between the sensor and the actuator. An original configuration of the piezoelectric sensor-actuator control device is presented, together with a theoretical interpretation. Experimental trials, also illustrated, show clearly that the proposed solution can be a smart and inexpensive alternative to the traditional control devices. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. SPIE Vol. 4540 343 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx
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