The charge trapping effect due to the exposure of alumina surfaces to plasma has been studied in a volume dielectric barrier discharge (DBD) in Ar and He noble gases. The long lasting charge trapping of alumina dielectric plates, used as barriers in DBDs, is evidenced by an ex situ thermoluminescence (TL) experiment performed with a standard and a custom two-dimensional (2D)-TL apparatus. The spatial density of trapped surface charges is found to be strongly correlated to the plasma morphology, and the surface spatial memory lasted for several minutes to hours after plasma exposure. In the case of Ar, the plasma channel impact signature on the surface shows a higher equivalent radiation dose with respect to the surface plasma wave and the post-discharge species signature. As a consequence, for the development of discharges, inside the dielectric surface the availability of lower energy trapped electrons is larger in the first region of plasma impact. The reported spatial memory increases the likelihood of the occurrence of plasma filaments in the same position in different runs. In He plasmas, the dielectric barrier shows an almost uniform distribution of trapped charges, meaning that there is no preferred region for the development of the discharge. In all cases a slight asymmetry was shown in the direction of the gas flow. This can be interpreted as being due to the long-living species moving in the direction of the gas flow, corresponding with the TL side experiment on the sample exposed to the plasma afterglow. The maximum values and the integral of the 2D-TL images showed a linear relation with the total charge per ac cycle, corresponding with findings for the TL glow curve. In conclusion, 2D-TL images allow the retrieval of information regarding the plasma surface interaction such as the plasma morphology, trap sites and their activation temperature.

We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009) an interruption of the broadcasting from the transmitter (RMC, France) happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic efocusing is inexistent. Our doubts on this action are reported.

In a previous study, an apparatus generating 1.8 GHz electromagnetic radiation for “in vivo” biomedical study was designed and implemented. The apparatus consisted of a reverberation chamber and it reproduced a habitat similar to the usual one for the laboratory animals. Plexiglas boxes with 300 cc physiological liquid were utilized as simple phantoms. For the measurements a small Electric Field Probe was used. The maximum SAR (Specific Absorption Rate) and average Power Efficiency Pe (SAR/input power) values obtained were quite low (“in vivo experiments”) and this was the drawback of the apparatus. In the present work, different modifications introduced in order to increase SAR and Power Efficiency are presented. In the new configuration, the dosimetry for the previous phantoms and for oil-in-gelatine phantoms was investigated and quite satisfactory SAR and Power Efficiency values were obtained, overcoming the previous drawback. In the first case the sensor was waterproofed, as in the previous study; in the other case a Plexiglas box with inside a tight shaped allocation for the measurement probe was realized. These measurement technologies could be applied to other media used for the phantoms.

We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009) an interruption of the broadcasting from the transmitter (RMC, France) happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic defocusing is inexistent. Our doubts on this action are reported.

Aims: Until now, studies related to the morphometric and morphological variations produced on peripheral blood leukocytes from healthy donors by exposure to 1.8 GHz electromagnetic radiation (EMR) yielded controversial results. The aim of this research work is to increase the statistics regarding the above mentioned variations. Methodology: By using a reverberation chamber, which provides a controlled EMR intensity, 108 samples of human leukocytes from healthy donors were exposed to EMR of different intensities (12±4 V/m, 22±6 V/m, 42±9 V/m and 78±10 V/m) for times ranging from 5 min to 24 h. Sham exposed blood samples of the same donors were considered as controls. Using a computerized morphometric method, microscopic observations of the area size occupied by each cell were conducted; in each case the dimensional measurements were carried out on three different samples (from different donors). Besides, morphological observations were conducted staining smeared blood samples with May-Grünwald-Giemsa. Results: Exposed and sham exposed leukocytes average size was compared using the Statistical GraphPad Prism 5.0 software. In 18% out of 108 cases examined, no effects dependent on EMR have been revealed. On the contrary, statistically significant variations in area of exposed leukocytes in comparison to non exposed cells were observed in 82% out of 108 cases examined. In 68% out of 108 cases an increase in leukocyte areas was demonstrated along with morphological variations of cells; in 14% out of 108 the cases, a decrease in leukocyte areas was observed. Conclusions: Even though this study needs a functional evaluation of leukocytes exposed to EMR, our results suggest that 1.8 GHz EMR is able to produce increase in the leukocyte areas as well as morphological alterations.

A new laboratory for the spectroscopy of natural radioactivity with a good energy resolution is presented. It consists of two distinct parts equipped, respectively, the first one with a HpGe g-ray detector, whose setup has been already completed, and the second one with large area Silicon a-ray detectors and a radiochemical section for thin a-samples preparation, whose setup is yet in progress and will be the argument of a separate work. The g-ray spectrometer was calibrated by means of IAEA Reference Materials n. 312, 313, 314 and 375. A large difference from the predictions of secular equilibrium emerged between the activities of 234Th and 230Th in Materials n. 312, 313 and 314.

In the last years disturbances in VLF/LF radio signals related to seismic activity have been presented. The radio data were collected by receivers located on the ground or on satellites. The ground-based research implies systematic data collection by a network of receivers. Since 2000 the "Pacific VLF network", conducted by Japanese researchers, has been in operation. During 2008 a radio receiver was developed by the Italian factory Elettronika (Palo del Colle, Bari). The receiver is equipment working in VLF and LF bands. It can monitor 10 frequencies distributed in these bands and, for each of them, it saves the power level. At the beginning of 2009, five receivers were made for the realization of the "European VLF/LF Network"; two were planned for Italy and one for Greece, Turkey and Romania, respectively. In 2010 the network was enlarged to include a new receiver installed in Portugal. In this work, first the receiver and its setting up in the different places are described. Then, several disturbances in the radio signals related to the transmitters, receivers, meteorological/geomagnetic conditions are presented and described.

In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

Polycrystalline diamond films with a thickness of about 2 μm were deposited by chemical vapour deposition on silicon substrates in continuous and pulsed wave regimes with duty cycle between 25% and 100%. The thermoluminescent behaviour of these films was analysed in the temperature range 323–723 K after β irradiation with doses in the range 7–107 Gy. All the films exhibit a dosimetric peak centred at about 592 K, showing a good linearity in the whole investigated dose range. The thermoluminescence analyses show that the intensity of the dosimetric peak is maximum for the continuous wave film, while it decreases for the pulsed wave samples. The variation of the crystalline quality and the purity of the films with the employed duty cycle, investigated via micro-Raman spectroscopy and room-temperature photoluminescence, indicates that the continuous wave (duty cycle=100%) film has the best quality, corresponding to the highest thermoluminescence efficiency.

In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz) and LF (150-300 kHz) bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed throughout Europe to establish a 'European VLF/LF Network'. At present, two of these are into operation in Italy, and the remaining four are located in Greece, Turkey, Portugal and Romania. For the present study, the LF radio data collected over about two years were analysed. At first, the day-time data and the night-time data were separated for each radio signal. Taking into account that the LF signals are characterized by ground-wave and sky-wave propagation modes, the day-time data are related to the ground wave and the night-time data to the sky wave. In this framework, the effects of solar activity and storm activity were defined in the different trends. Then, the earthquakes with M ≥5.0 that occurred over the same period were selected, as those located in a 300-km radius around each receiver/transmitter and within the 5th Fresnel zone related to each transmitter-receiver path. Where possible, the wavelet analysis was applied on the time series of the radio signal intensity, and some anomalies related to previous earthquakes were revealed. Except for some doubt in one case, success appears to have been obtained in all of the cases related to the 300 km circles in for the ground waves and the sky waves. For the Fresnel cases, success in two cases and one failure were seen in analysing the sky waves. The failure occurred in August/September, and might be related to the disturbed conditions of the ionosphere in summer. © 2012 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved