Sistema automatico di protezione e di sicurezza per sistemi fotovoltaici.

Sistema automatico di protezione e di sicurezza per sistemi fotovoltaici. The aim of the invention is to define a safety device for workers and/or operators in photovoltaic systems (PV) both during interventions of normal use (maintenance) and during emergency condition (fire, etc.).Thus, the permanence of continuous voltage along the stretch-line included between the inverter and the panel is still a problem that has not found solution. The scientific-technical objectives of the invention can be considered in the context of the evolving technology of PV system providing great security of the system itself. The system consists of a device, which prevent irradiation of the solar rays from th…

Maintance by water-cleaning and efficiency reduction of pv panels

With the increase in the use of solar energy, both in civil and industrial environments, the problem of maintenance of photovoltaic panels becomes extremely important. In this work attention is restricted to the problem of cleaning and safety conditions of the photo-voltaic (PV) panels and a brief review of main effects determining their efficiency reduction are reported. The discussion related to problems and unsafe functioning conditions concludes this paper.

Experimental investigation of flow turbulent structure in a high-amplitude vegetated meandering laboratory flume

The present work focuses on high-curved channels which are characterized by a complex flow turbulent structure. The specific aim of work is to analyze the evolution of turbulent coherent motion in the pres-ence of vegetation on the bed.

Jet interacting with vegetation in a rotating basin

Contaminants, nutrients and sediment particles flow into inland and coastal water bodies often forming turbulent jets. The aim of the present research is to improve our capability to describe how jets interact with the environment they discharge into, providing useful insights for possible mitigation of undesired and harmful impacts. Here, we focus on the case of a jet interacting with an obstructed flow under the effect of the Coriolis force as is often the case with large scale rivers discharging into the sea in vegetated environments.

Simulation of scouring process downstream of a hydraulic structure and analysis of the effect of vegetation

In the present work a 1-D numerical model is applied to simulate the evolution of scouring process and the variation of the bed shear stress during transients. By the help of the model and by using experimental data collected in a straight flume, the paper also investigates how the presence of flexible vegetation on the bed could limit the evolution of the erosion process.

Establishing mussel behaviour as a monitoring tool to measure climatic disturbances

Freshwater mussels (FM) are suitable biological indicators to assess environmental stressors. Behaviour is a good parameter to measure rapid mussel’s responses. In this sense, valvometric method, that exploits the Hall sensor (real-time remote monitoring tool), has been used to measure the behavioural responses of mussels (valve opening amplitude and valve opening-closure frequency). During the last two decades, these methodologies have been used to measure the presence of the pollutants in the waterbodies. However, studies that focus on physical disturbances in the environment related to climate changes are lacking. Since future climatic scenarios in Europe predict an increase in temperatu…

Mussels behavior as a tool to measure hydrological stressors

Freshwater mussels are considered suitable bioindicators and used in real-time remote monitoring systems to detecting disturbances on ecosystems. One of the most successful methods is the valvometric technique that exploits the Hall sensor to measure the valve gaping behavior of mussels. The duration and frequency of valve opening amplitude and closure can therefore be recorded. These technologies have been used in the past to detect pollutants in the water, whereas studies that address the impact of hydromorphological pressures are still lacking. The main aim of the present study is to assess the influence of flow with sediment transport as well, both in steady and in unsteady (transient) …

Experimental analysis of the effect of non-uniform submerged vegetation on flow characteristics at the apex section of a meandering laboratory flume

Variazione delle caratteristiche delle radici di una vegetazione flessibile e matura in un canale meandriforme: risultati preliminari

ASPETTI CHIAVE • Interazione corrente-vegetazione in un canale meandriforme • Variazione delle caratteristiche geometriche delle radici di una vegetazione matura lungo la curva • Variazione delle caratteristiche meccaniche delle radici di una vegetazione matura lungo la curva

Effects of submerged vegetation on flow and turbulence characteristics at the apex section of a meandering flume

Understanding flow characteristics and turbulent structure in the presence of vegetation is important with respect to environmental processes as sediment transport and mixing of transported quantities. In the present paper attention is focused on the kinematic and turbulent processes in presence of flexible submerged vegetation. In particular, the effect of vegetation on the flux of mass distribution and the process of transport is investigated. The analysis is performed with the aid of detailed experimental data collected in a laboratory channel both in the absence and in presence of flexible and submerged vegetation. Results essentially confirms that mass exchanges in the presence of vege…

La vegetazione a protezione di processi di escavazione localizzata: risultati di uno studio sperimentale

Diversi studi di letteratura mostrano come la vegetazione debba essere considerata un fattore chiave per analizzare i meccanismi di trasporto che si realizzano lungo un corso d’acqua naturale (Jarvela, 2002; Folkard, 2011). In particolare, la presenza di vegetazione sul fondo e/o sulle sponde del corso d’acqua contribuisce sia a stabilizzare i sedimenti che ad aumentare la resistenza al moto della corrente (Tsujimoto 1999; Nepf and Vivoni, 2000; Afzalimehr and Dey, 2009; Nepf, 2012), influenzando i processi di trasporto solido e i conseguenti fenomeni di erosione e di deposito lungo lo stesso corso d’acqua. In questo contesto, nel presente lavoro sono riportati alcuni risultati di uno studi…

TIME EVOLUTION OF LOCAL SCOURING DOWNSTREAM OF A RIGID BED:lessons learned from experiments

This present work concerns the phenomenon of local erosion occurring downstream a rigid bed of a structure constructed along a river. In particular, attention is focused on the time evolution of the maximum scour depth. This chapter reports a brief review of findings obtained by author using both data appositely collected in a laboratory channel and literature data.

Estimation of velocity profile in a hyper-concentrated flow: a critical analysis of Bagnold equation

Debris flow velocity is an important factor which influences the impact forces and runup. Due to the complexity of the phenomenon, it is difficult to define predictive methodologies. The present work reports some results of an experimental run conducted in order to investigate the velocity and sediment concentration distributions. A modified Bagnold’s approach to calculate the vertical distribution of flow velocity is presented.

Effects of submerged vegetation on flow and turbulence characteristics at the apex bend of a meandering flume

Understanding flow characteristics and turbulent structure in the presence of vegetation is important with respect to environmental processes as sediment transport and mixing of transported quantities. In the present paper attention is focused on the kinematic and turbulent processes in presence of flexible submerged vegetation. In particular, the effect of vegetation on the flux of mass distribution and the process of transport is investigated. The analysis is performed with the aid of detailed experimental data collected in a laboratory channel both in the absence and in presence of flexible and submerged vegetation. Results essentially confirms that mass exchanges in the presence of vege…

Application of the entropy model to high-curved turbulent flows

The entropy-based approach allows the estimation of the mean flow velocity in open channel flow by using the maximum flow velocity. The entropy model allows to correlate the mean velocity, um, and the maximum velocity, umax by means of a linear relationship, um, = Φ (M) umax, which depends on the entropy parameter, M, characteristic of the fluvial section ([1]). The present work also focuses on high-curved channels where the secondary motion, which is also induced by the channel’s curvature, evolves along the bend. The study is motivated by the fact that meandering bends have radii of curvature continuously variable in stream-wise direction so that convective flow accelerations occur and th…

L’acqua e le risorse sostenibili a sostegno delle condizioni di vivibilità locale

In questo lavoro sono descritte le azioni cche consentono l'uso della risorsa idrica in paesi sottosviluppati

Mixing processes in vegetated rivers: experimental investigation in a laboratory flume

The presence of vegetation in rivers exerts an important ecological function and is very important to maintain suitable habitat. Especially in recent years, some researchers (among others Perrucca et al., 2007) have focused their attention on the role of vegetation in channel’s morphodynamics. Alteration of hydrological conditions in fluvial systems inevitably leads to changes in river morphology, riparian or riverbed vegetation and ecosystems. Riparian vegetation distribution could also change in time and in space depending on the combination of factors affecting the settling and growth of vegetated elements. In the present paper attention is focused on the turbulent and mixing processes i…