Search results for " Oscillation"
showing 10 items of 845 documents
Intensity and spatial extent of droughts in southern Africa
2005
International audience; The standardized precipitation index allows for monitoring the intensity and spatial extent of droughts at different time scales. We used it to do a retrospective analysis of the spatial extent of droughts in Southern Africa (South of 10°S), from 1901 to 1999. Accordingly, the 8 most severe droughts at the 6-month scale (October–April) for the summer rainfall region of Southern Africa ended in 1916, 1924, 1933, 1949, 1970, 1983, 1992 and 1995. At the 2-year scale, they ended in 1906, 1933, 1983, 1984, 1992, 1993, 1995 and 1996. Areas affected by those droughts ranged from 3.4 to 2 106 km2. Eight of those 12 years are El Niño years. Preliminary data indicates that 200…
Has the Northern Hemisphere been warming or cooling during the boreal winter of the last few decades?
2013
Abstract The Intergovernmental Panel on Climate Change (IPCC) reported a significant rise of the global mean surface temperature over the last 100 years, with a rate of warming over the last few decades almost double that over the last 100 years. The rate of warming is higher at land surfaces over the Northern Hemisphere (NH), and particularly extreme warming is occurring over the Arctic. In spite of the global warming trend, some asymmetries have been observed. In a recent study, a widespread cooling over the NH during the boreal winter season was reported, although other previous studies observed a warming during this season. In this paper we report trends in winter air temperatures over …
How dry was the Younger Dryas? Evidence from a coupled <i>δ</i><sup>2</sup>H–<i&gt…
2019
Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 an…
Advances in Design, Simulation and Manufacturing IV
2021
This book reports on topics at the interface between mechanical and chemical engineering, emphasizing design, simulation, and manufacturing. Specifically, it covers recent developments in the mechanics of solids and structures, numerical simulation of coupled problems, including fatigue, fluid behavior, particle movement, pressure distribution. Further, it reports on developments in chemical process technology, heat and mass transfer, energy-efficient technologies, and industrial ecology. Based on the 4th International Conference on Design, Simulation, Manufacturing: The Innovation Exchange (DSMIE-2021), held on June 8-11, 2021, in Lviv, Ukraine, this second volume of a 2-volume set provide…
Hidden oscillations in nonlinear control systems
2011
Abstract The method of harmonic linearization, numerical methods, and the applied bifurcation theory together discover new opportunities for analysis of hidden oscillations of control systems. In the present paper new analytical-numerical algorithm for hidden oscillation localization is discussed. Counterexamples construction to Aizerman's conjecture and Kalman's conjecture on absolute stability of control systems are considered.
QPO emission from moving hot spots on the surface of neutron stars: a model
2009
We present recent results of 3D magnetohydrodynamic simulations of neutron stars with small misalignment angles, as regards the features in lightcurves produced by regular movements of the hot spots during accretion onto the star. In particular, we show that the variation of position of the hot spot created by the infalling matter, as observed in 3D simulations, can produce high frequency Quasi Periodic Oscillations with frequencies associated with the inner zone of the disk. Previously reported simulations showed that the usual assumption of a fixed hot spot near the polar region is valid only for misalignment angles relatively large. Otherwise, two phenomena challenge the assumption: one …
High energy neutrino telescopes in the Northern Hemisphere
2012
We review the status and results of the high energy neutrino telescopes in the Northern Hemisphere, namely ANTARES and Baikal (NT200+).
Searching for neutrino oscillation parameters in long baseline experiments
2016
Vihonen, Sampsa "Searching for neutrino oscillation parameters in long baseline experiments" in Proceedings, Magellan Workshop: Connecting Neutrino Physics and Astronomy / Dahmke, Stefan K.G., Meyer, Mikko, Vanhoefer, Laura (eds.), Deutsches Elektronen-Synchrotron, DESY : 2016 ; Magellan Workshop, 2016-03-17 - 2016-03-18, Hamburg Magellan Workshop, Hamburg, Germany, 17 Mar 2016 - 18 Mar 2016 ; DESY-PROC 65-70(2016). doi:10.3204/DESY-PROC-2016-05/8
Probing Planck scale physics with IceCube
2005
Neutrino oscillations can be affected by decoherence induced e.g. by Planck scale suppressed interactions with the space-time foam predicted in some approaches to quantum gravity. We study the prospects for observing such effects at IceCube, using the likely flux of TeV antineutrinos from the Cygnus spiral arm. We formulate the statistical analysis for evaluating the sensitivity to quantum decoherence in the presence of the background from atmospheric neutrinos, as well as from plausible cosmic neutrino sources. We demonstrate that IceCube will improve the sensitivity to decoherence effects of ${\cal O}(E^2/M_{\rm Pl})$ by 17 orders of magnitude over present limits and, moreover, that it ca…
Generalized mu-tau reflection symmetry and leptonic CP violation
2016
14 pages.- 9 figures