Central Au on Au collisions Gobbi, Adriano; Alard, J.P.; Amouroux, V. ...
Nuclear Physics A,
02/1995, Letnik:
583
Journal Article, Conference Proceeding
Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z 16) and velocity of the products were detected with full ...azimuthal acceptance at laboratory angles of 1-30 degrees. Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6-90 degrees. Central collisions representing about 1 % of the reaction cross section were selected by requiring high total transverse energy, but vanishing sideflow. The velocity space distributions and yields of the emitted fragments are reported. The data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the Quantum Molecular Model is presented.
Using the FOPI facility at GSI Darmstadt complete data of Au on Au collisions at 150ital A MeV were collected for charged products (ital Z=1--15) at laboratory angles 1degreeleThetasub lable30degree. ...Central collisions were selected by applying various criteria. The kinetic energy spectra of fragments from an isolated midrapidity source are investigated in detail for center-of-mass angles 25degreeleThetasub c.m.le45degree. The heavy products (ital Zge3) are used to determine the collective energy which is found to be at least 10ital A MeV.
Droughts often evolve gradually and cover large areas, and therefore, affect many people and activities. This motivates developing techniques to integrate different satellite observations, to cover ...large areas, and understand spatial and temporal variability of droughts. In this study, we apply probabilistic techniques to generate satellite derived meteorological, hydrological, and hydro-meteorological drought indices for the world's 156 major river basins covering 2003–2016. The data includes Terrestrial Water Storage (TWS) estimates from the Gravity Recovery And Climate Experiment (GRACE) mission, along with soil moisture, precipitation, and evapotranspiration reanalysis. Different drought characteristics of trends, occurrences, areal-extent, and frequencies corresponding to 3-, 6-, 12-, and 24-month timescales are extracted from these indices. Drought evolution within selected basins of Africa, America, and Asia is interpreted. Canonical Correlation Analysis (CCA) is then applied to find the relationship between global hydro-meteorological droughts and satellite derived Sea Surface Temperature (SST) changes. This relationship is then used to extract regions, where droughts and teleconnections are strongly interrelated. Our numerical results indicate that the 3- to 6-month hydrological droughts occur more frequently than the other timescales. Longer memory of water storage changes (than water fluxes) has found to be the reason of detecting extended hydrological droughts in regions such as the Middle East and Northern Africa. Through CCA, we show that the El Niño Southern Oscillation (ENSO) has major impact on the magnitude and evolution of hydrological droughts in regions such as the northern parts of Asia and most parts of the Australian continent between 2006 and 2011, as well as droughts in the Amazon basin, South Asia, and North Africa between 2010 and 2012. The Indian ocean Dipole (IOD) and North Atlantic Oscillation (NAO) are found to have regional influence on the evolution of hydrological droughts.
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•Using GRACE TWS results in more intense drought indices than soil-moisture reanalysis.•The areal extent of the 2003–2016 hydrological droughts is generally increasing.•Droughts of the Middle East, America, and South Asia are intense and being worsened.•SST and CCA are efficient to explore teleconnections and droughts hot spots.•The 2006 and 2011 droughts in Asia and Australia are largely correlated with ENSO.
The trigger system of the Alice dimuon spectrometer is based on RPC detectors. We present experimental results of a beam test about rate capability, time resolution and cluster size of single gap RPC ...detectors operating both in ‘streamer mode’ and in ‘avalanche mode’. We have compared the performances of small chambers (50×50 cm
2) built with bakelite of different resistivity, from ∼ 3 · 10
9 Ωcm to ∼ 3 · 10
11 Ωcm. For the low resistivity RPC we obtained a rate capability of several hundreds of Hz/cm
2 when it is operating in ‘streamer mode’, and of several thousands of Hz/cm
2 when it is operating in ‘avalanche mode’.
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