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The effect of the wind speed and direction on the arrays in a 50 kW plant was analyzed along several days. The wind is measured in different positions of the plant: the general plant meteorological station, the module's boundary layer and the close surroundings of the array. The averaged thermal resistance between the back of the module and the ambient is calculated and its dependence with the wind direction analyzed. Early results suggest that Northern wind has a better cooling effect than Western and Eastern winds.

Results of several experimental tests performed to analyze the potential of CPV modules based on a single reflective stage and a fluid dielectric are summarized in this paper. Special emphasis is put on analyzing outdoor performance. The improved thermal design maintains the temperature difference between the solar cell and the ambient below 37°C during outdoor operation. In addition, the system performance under different spectra is analyzed experimentally determining the limiting subcell within the multijunction solar cell under variable spectral conditions.

The X-ray binary XTE J1817-330 was discovered in outburst on 26 January 2006 with RXTE/ASM. One year later, another X-ray transient discovered in 1996, XTE J1856+053, was detected by RXTE during a new outburst on 28 February 2007. We triggered XMM-Newton target of opportunity observations on these two objects to constrain their parameters and search for a stellar black holes. We summarize the properties of these two X-ray transients and show that the soft X-ray spectra indicate indeed the presence of an accreting stellar black hole in each of the two systems., to appear in the proceedings of the Second Kolkata Conference on Observational Evidence for Black Holes in the Universe, Feb. 2008, Editor Sandip Chakrabarti, AIP

The black hole candidate XTE J1817-330 was discovered in outburst on 26 January 2006 with RXTE/ASM. One year later, on 28 February 2007, another X-ray transient discovered in 1996, XTE J1856+053, was detected by RXTE during a new outburst. We report on the spectra obtained by XMM-Newton of these two black hole candidates., Comment: Replaced with corrected version

ROSAT observed 39 classical novae less than 10 years after outburst, but only three of them (Nova Mus 1983 (GQ Mus), Nova Cyg 1992 (V1974 Cyg) and Nova LMC 1995) were found to be soft X‐ray sources (0.1–0.4 keV), as a result of steady hydrogen burning on the white dwarf’s surface. V1974 Cyg also showed a harder component, and Nova Her 1991 (V838 Her) and Nova Pup 1991 (V351 Pup) were detected only in the ROSAT hard band (0.4–2.4 keV). This hard component was fitted with a thermal plasma model, and the required temperature was understood to be caused by shocks in the ejecta. In this work, we study the possible contribution to the X‐ray spectrum of the photoionization of the ejected gas shell by the central source. We use the XSTAR photoionization code to simulate the X‐ray spectrum of a classical nova during the post‐outburst phase. We compare these results with ROSAT/PSPC spectra of V1974 Cyg.

Observations of five recent Galactic classical novae with XMM‐Newton have been performed. The main goal was to monitor (at equal time intervals of around 6 months) if the sources were emitting X‐rays and to get their spectral properties. The unprecedented sensitivity of the XMM‐Newton instruments allows for detection of recent novae with relatively short observation times, provided that they are still emitting. The broad spectral range of the EPIC cameras, as compared with ROSAT/PSPC, allows for a better coverage of the emission. Four out of five observed sources are still emitting 2 to 4 years after outburst (in the whole range 0.3–8.0 keV), which is a much larger fraction than the one from ROSAT observations. On the other hand, the lack of information below 0.3 keV (as compared with the excellent sensitivity of ROSAT/PSPC) together with the small observation times do not permit to get an unambiguous interpretation of the data.