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The oscillating-water-column (OWC) system is one of the most developed wave energy conversion technologies, and several prototypes have been deployed and tested on the sea. Noise emission is essential to this technology's long-term environmental impact assessment. The power take-off system of an OWC comprises a self-rectifying air turbine that directly drives an electrical generator. The paper compares the noise emission of a biradial turbine with that of a Wells turbine. The noise emission of the biradial turbine was measured at the Instituto Superior Técnico variable-flow test rig, while the Wells turbine data were collected in the literature. Acoustic measurement procedures followed the guidelines of the ISO 3746 Standard. A definition of specific noise level is used to compare the noise emission from geometrically similar air turbines or other air turbines performing the same duty. The results show that the noise levels of the biradial turbine are significantly lower than those of the Wells turbine at off-design conditions for the same pneumatic power. • Methodology for measuring noise emission from air turbines. • Experimental characterisation of the acoustic emission of a biradial turbine. • Use of a specific noise level to compare air turbines. • Comparison of noise emission of a biradial turbine with a Wells turbine. • Wells turbines are significantly noisier than biradial turbines at off-design conditions. [ABSTRACT FROM AUTHOR]

Summary: Proliferative and necrotizing pneumonia (PNP) is a form of interstitial pneumonia that occurs in weaning and post-weaning pigs. PNP is characterized by hypertrophy and hyperplasia of type II pneumocytes and coagulative necrosis and granular debris within alveolar spaces. Canadian and European studies suggest that the porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are the main causes of the disease, but Aujezsky''s disease virus (ADV) and swine influenza virus (SIV) have also been considered as potential aetiological agents. An immunohistochemical study was carried out on the lungs of 28 Italian pigs with PNP in order to evaluate the role of PRRSV, PCV2 and ADV in PNP lesions. PRRSV infection was identified in the lungs of 11 pigs, PCV2 in the lungs of four pigs and coinfection with both viruses in the lungs of eight pigs. Neither virus was detected in the lungs of the remaining five pigs. ADV antigen was not detected in any sample. The principle aetiological agent of PNP in Italy therefore appears to be PRRSV. Coinfection with PRRSV and PCV2 is characterized by more severe microscopical changes in affected lungs. [Copyright &y& Elsevier]

Ultrasound has attracted great interest in recent years and its application in food freezing has shown promising advantages. In the present study the application of ultrasound during immersion freezing of potato cubes was studied and particular attention was given to the effects on supercooling process. Ultrasound, produced through a 35kHz sonotrode, was applied when the temperature in the geometrical center of potato sample was in the range from −0.1 to −3.0°C. Several freezing parameters, as nucleation temperature and time, supercooling, initial freezing temperature, transition phase and global freezing duration, were evaluated and discussed. A significant anticipation of nucleation was detected when the ultrasound application temperature was lower than −0.1°C; moreover it was found a linear correlation between ultrasound irradiation temperature and supercooling reached in potato samples; finally a reduction in freezing time was recorded when ultrasound was applied at −2.0°C. Industrial relevance: Ultrasound has acquired relevance in several industrial sectors, including food science and technology. In the present investigation power ultrasound has been studied in assisting and accelerating immersion freezing of potato cubes, obtaining promising results. In fact it was found that ultrasound was able to induce nucleation in the centre of potato cubes, interrupting the supercooling process. Moreover, under particular operative conditions, the freezing time of ultrasound-assisted potato cubes was significantly reduced with respect to non–irradiated samples. The results achieved demonstrate that the application of power ultrasound during immersion freezing has a great potential in the control of the freezing process. In particular the possibility of reduction of the freezing time and costs, as well as the influence of ultrasound on quality, stability and sensory properties of frozen food have a crucial importance to food industry and have to be widely investigated. [ABSTRACT FROM AUTHOR]