In the present work, we investigated the scattering and spectrally resolved absorption properties of nanofluids consisting in aqueous and glycol suspensions of single-wall carbon nanohorns. The characteristics of these nanofluids were evaluated in view of their use as sunlight absorber fluids in a solar device. The observed nanoparticle-induced differences in optical properties appeared promising, leading to a considerably higher sunlight absorption with respect to the pure base fluids. Scattered light was found to be not more than about 5% with respect to the total attenuation of light. Both these effects, together with the possible chemical functionalization of carbon nanohorns, make this new kind of nanofluids very interesting for increasing the overall efficiency of the sunlight exploiting device. PACS 78.40.Ri, 78.35.+c, 78.67.Bf, 88.40.fh, 88.40.fr, 81.05.U.

Lipoptena fortisetosa, a deer ked native to Japan, has established itself in several European countries and was recently recorded in Italy. This hippoboscid ectoparasite can develop high density populations, causing annoyance to animals and concern regarding the potential risk of transmitting pathogens to humans. No monitoring or control methods for L. fortisetosa have been applied or tested up to now. This research evaluated the possible response of L. fortisetosa winged adults to different colours as the basis for a monitoring and control strategy. In the summer of 2020, a series of six differently coloured sticky panels were randomly set as traps in a wooded area used by deer for resting. The results indicated a clear preference of the deer ked for the blue panels that caught the highest number of flies during the experimental period. Lower numbers of flies were trapped on the red, green, black, and white panels, with the yellow panels recording the fewest captures. The response clearly demonstrates that this species displays a colour preference, and that coloured traps might be useful for monitoring and limiting this biting ectoparasite in natural areas harbouring wildlife and visited by people.

The Scheffler type concentrator is a curved metal reflector particularly suitable for solar thermal systems with a receiver fixed to the ground. Its operating principle is to deform the reflector throughout the year to optimize its performance in collecting sunlight. This study analyses the optical performance of a Scheffler reflector during the year. A CAD software tool is utilized to reproduce the mechanical deformations of a real Scheffler concentrator and the shape of the light spot on the receiver is analyzed by means of raytracing simulations. The starting configuration is the equinoctial paraboloid, which produces a point-like spot on the two equinox days only. On all other days of the year, this paraboloid is deformed in a suitable way in order to keep the spot as small as possible, but, even so, it is no longer a point-like spot. In the present work the simulated light distributions on the receiver, generated by the paraboloids (deformed or original), are compared. The results confirm the working principle of the Scheffler type concentrator and allow correctly sizing the receiver.

In this paper we present a comparison between the data obtained by IR Digital Holography and conventional accelerometers in order to evaluate the structural stability of buildings. The tests have carried out on historical buildings located in Tuscany (Italy) under the continuos surveillance of the Italian Civil Protection Department by means of accelerometers networks. From the comparison it emerges that the holographic technique can be profitably used in the field of dynamical analysis of structures thanks to its high sensitivity and to the possibility to operate from remote. Indeed, the holographic technique is able to detect micro-movements of the order of 1/100 of the used laser wavelength at 10.6 μm without entering the structures.

The electroluminescence test is an experiment typically used to verify the behavior of the photovoltaic cell and to qualitatively check its integrity. It works by operating the photovoltaic cell as a diode polarized directly: the cells that light up in a module indicate how many of them work. This test provides an estimate of the maximum performance of the entire photovoltaic module. A qualitative inspection was performed by electroluminescence tests on 48 modules of photovoltaic cells. They had already been installed on a small-size concentration solar plant before the test and some modules had reached a lower level of performance than expected. A first electroluminescence test was performed, which showed that only 61.5% of the photocells worked. Since there were visible signs of humidity within the various modules, some of the inoperative modules underwent a dehumidification treatment in a climatic chamber. A second electroluminescence test showed that the percentage of functioning cells had increased to 66.3% after the drying treatment.

In concentrating solar systems, it is essential to study the optical losses of the collectors. A fundamental parameter is the intercept factor, namely, the fraction of sunrays reflected by the concentrator that reaches the receiver. Optical profilometry studies the relationship between the collector profile and the intercept factor, which influences the collection efficiency. Profilometric analyses were performed on a micro-parabolic trough collector (m-PTC), with reduced sizes and greater mirror curvature than a usual PTC. The proposed technique projects a luminous pattern (structured light) both on the collector with an opaque covering and on a flat reference plane. Measurement set-up and calibration technique were developed for m-PTC. A program coded in Python analyzed the images and reconstructs the mirror profile. The tilted reference plane was reconstructed using an original geometric model and a calibration procedure. The focal length of each parabolic section was calculated, providing information on surface defects in the mirror. An important parameter obtained was the displacement of the focus of the parabola with respect to the ideal position. Using this value, the intercept factor was estimated to be 0.89. The proposed technique was validated by comparing the results with an independent profilometric study applied to the same m-PTC.