Experimental investigations in winding and unwinding operations

The trend in winding in the paper industry can be simply characterized by : wider and faster with more dense webs with a lower level of accepted defects. This is valid for paper production and printing, especially in rotogravure.Europe's rotogravure industry is investing in wider printing machines : 3.08 m -3.18 m - 3.48 m - 3.52 m - 3.60 m. These machines are already ordered and the widest will start up end of 1997. In the unwinding process the techniques of fiber cores is running to the edge of physical limits : vibrations. Experimental natural frequency analyses and trials on a core rotational test stand demonstrate limits and potentials of cores and unwind stands.Jumbo reels in roto are exceeding masses of 5 tons. In the unwinding situation bursts near the core occur - the more often, the wider and heavier the reels are. A systematic winding test on a production winder with a modified unwind stand demonstrate the creation of bursts and leads to a method to avoid center bursts in jumbo reels for rotogravure.In paper production there is an idea to produce machine wide reels with high diameters for a high efficiency an a minimum of paper losses. Limits in winding of LWC base paper are observed because of center bursts. Investigations of thermal phenomena in the center of big reels show characteristic temperature structures during winding. Bursts can be detected because they produce a local temperature "hot" spot. From this ideas can be created to develop a new winding test or inspection system to detect winding structures and winding failures

Ammando 61, 62 , F. de Palma 45

See paper for full list of authors - 13 pages, 9 figures, accepted for publication in A&AInternational audienceThe addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV. Such an extension of the instrument's energy range is particularly beneficial for studies of Active Galactic Nuclei with soft spectra, as expected for those at a redshift > 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553+113 (0.43 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Multiple observational campaigns of PKS 2155-304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument. A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters. The energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to energies of 80 GeV for PKS 2155-304, which transits near zenith, and 110 GeV for the more northern PG 1553+113. The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0 sigma statistical preference for non-zero curvature for PKS 2155-304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E ~ 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155-304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties