Ferruccio Giametta

Vibration analysis using a contactless acquisition system

The problem of vibration measurement has assumed increasing importance in recent years for different aspects. In the first phase of this study an analysis of vibrations by means of contact accelerometers was carried out to study a tree shaking machine used in the mechanical harvesting of olives. Then a kinematic analysis of motion with a contactless method was carried out on a belt transmission system equipped with three pulleys: a high speed camera was used, able to capture up to 500 frames per second thus to follow the position of any moving point of the mechanical system under investigation. Vibrations were acquired detecting the positions during time of a marker fixed on the belt. The proposed method made it possible to analyse the mechanism and verify both known behaviours and neglected aspects in the usual kinematic analysis carried out using acceleration measurements.

Microclimate measuring and fluid-dynamic simulation in an industrial broiler house: testing of an experimental ventilation system.

In 2011, strains of West Nile Virus (WNV) belonging to lineage 1 spread for the first time in Sardinia region (Italy). In contrast to previous WNV Italian incursion, the strains were found in Culex modestus and, more surprisingly, they were able to cause severe clinical signs in the affected birds. Based on the partial sequence of the NS3 encoding gene, the Sardinian WNV strains demonstrated a high similarity with the other WNV strains recently detected in the Mediterranean Basin. Nonetheless, the 2011 Sardinian sequences were grouped in a distinct sub-cluster. Both the NS3-249P and NS3-249T genotypes were detected in the Sardinian outbreaks confirming that the co-circulation of different genotypes in the affected population might be common for WNV as for many RNA viruses. No association, however, was observed between virulence and viral genotype.

Experimental study of a mechanical ventilation system in a greenhouse

Greenhouse cultivation is one of the most energy intensive activities in agriculture. This is especially true in cold climate zone. Generally heating systems involves boilers fed with fossil fuels. This means low yields of the heat generator and high pollutant emissions. Moreover, the increase of annual crop yield in greenhouses is possible only through a very close control of the internal conditions. Ventilation systems could allow proper control of temperature, relative humidity and CO2 rate. For this purpose a prototype of a mechanical ventilation unit was installed at service of a mini-tunnel greenhouse. The recovery unit is equipped with a heat pump and is able to increase the thermal energy recovered, by the flow of exhaust air, through a high efficiency heat exchanger. A first study was carried out to evaluate the thermophysical and energy performances of the system during the heating season. The experimental apparatus consists of mechanical ventilation system, a perforated duct for air distribution, a fog system to adjust humidity and a supervision system to acquire the field data. Another dedicated supervision system allows to measure and collect all the parameters of the prototype, such as thermophysical parameter of the air flow, thermophysical parameter of the refrigerant circuit of the heat pump, status and alarms of the unit. To characterize the whole system under investigation the main data measured are temperature, relative humidity and carbon dioxide inside the greenhouse and temperature in all section of the prototype. Other two mini-tunnel greenhouses are monitored as references. One is heated with radiant tubes placed on the bench and humidified with a fog system, the other is completely passively heated (without heating system) and humidified with the same fog system. A First test was performed to evaluate the ability of the system to regulate the indoor temperature of the greenhouse with a set point of 27 °C. By using a temperature probe installed on the return side of the machine, the results shown an appropriate temperature regulation.