Search results for " bubbles"

Detection potential of the KM3NeT detector for high-energy neutrinos from the Fermi bubbles

2013

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E-2 spectrum from two large areas, spanning 50 above and below the Galactic centre (the "Fermi bubbles"). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles with the future multi-km(3) neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the resul…

A search for neutrino emission from the Fermi bubbles with the ANTARES telescope

2014

Adrián-Martínez, S. et al.

Digitālo mediju ietekme uz lēmumu pieņemšanu un demokrātiju

2018

Mūsdienās tādu tehnoloģiju progress kā mākslīgais intelekts apvienojumā ar Lielo Datu analīzi ir devis iespēju ievākt, uzturēt un analizēt milzīgus datu apjomus. Progress digitālajā jomā ietekmē ne tikai tirgus ekonomiku, bet arī politisko līdzdalību. Digitālie mediji spēj apvienot līdzīgi domājošos, iedrošināt sociālas aktivitātes, mazināt plaisas starp sabiedrības grupām, kā arī paaugstināt politisko līdzdalību valstī un veicināt izglītību, tomēr ir pastiprinātas bažas par to, ka digitālo mediju platformas var tikt izmantotas, lai izplatītu propagandas vēstījumus, kas is spējīga piesaistīt lielu auditoriju. Automātiskajiem filtrēšanas mehānismiem var piemist diskriminējošs raksturs, ietek…

CFD prediction of bubbles local gas hold-up in 2-dimensional gas-solid fluidized beds

2008

Cavitation of electron bubbles in liquid parahydrogen

2011

Within a finite-temperature density functional approach, we have investigated the structure of electron bubbles in liquid parahydrogen below the saturated vapour pressure, determining the critical pressure at which electron bubbles explode as a function of temperature. The electron-parahydrogen interaction has been modelled by a Hartree-type local potential fitted to the experimental value of the conduction band-edge for a delocalized electron in pH(2). We have found that the pressure for bubble explosion is, in absolute value, about a factor of two smaller than that of the homogeneous cavitation pressure in the liquid. Comparison with the results obtained within the capillary model shows t…

Bubbles and Crowding-in of Capital via a Savings Glut

2017

This paper uncovers a mechanism by which bubbles crowd in capital investment. If capital formation is initially depressed by a binding credit constraint, a bubble triggers a savings glut. Higher returns in a new bubbly equilibrium attract additional savings, which are channeled to expand investment at the extensive margin, leading to permanently higher capital, output, and wages. We demonstrate that crowding-in through this channel is a robust phenomenon that occurs along the entire time path.

Conduit dynamics and post explosion degassing on Stromboli: A combined UV camera and numerical modeling treatment.

2016

Abstract Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus coda SO2 masses of ≈18–225 kg. Numerical simulations of gas slug ascent show that substantial proportions of the initial gas mass can be distributed into a train of “daughter bubbles” released from the base of the slug, which we suggest, generate the codas, on bursting at the surface. This process could also cause transitioning of slugs i…

Bubbles in China

2010

This study examines rational bubbles in Chinese stock markets and China-related share indices in Hong Kong. A duration dependence test is employed for both monthly and weekly abnormal market returns of the Shanghai and Shenzhen A- and B-markets, as well as for the Hong Kong China Enterprises and China Affiliated Corporations indices. The test results are mixed, as weekly data demonstrate bubbles for all of the Mainland Chinese stock markets, but monthly data do not show bubbles for any of the examined markets. Neither of the datasets indicates bubbles in the Hong Kong markets. Results indicate that, in terms of bubbles, segmentation does not play a significant role in bubble existence and t…

Numerical model for the shear rheology of two-dimensional wet foams with deformable bubbles

2014

Shearing of two-dimensional wet foam is simulated using an introduced numerical model, and results are compared to those of experiments. This model features realistically deformable bubbles, which distinguishes it from previously used models for wet foam. The internal bubble dynamics and their contact interactions are also separated in the model, making it possible to investigate the effects of the related microscale properties of the model on the macroscale phenomena. Validity of model assumptions was proved here by agreement between the simulated and measured Herschel-Bulkley rheology, and shear-induced relaxation times. This model also suggests a relationship between the shear stress and…

Mode-particle Interactions as Sources of Gamma-ray Bubbles in the Galaxy

A plasma outflow coming from the center of Our Galaxy is simulated by an ion beam reaching a nearly stationary magnetic field that can excite lower hybrid waves efficiently in the rarefied plasma (10-2-10-4 cm-3) surrounding the whole galaxy. The electrostatic lower hybrid waves are driven to instability via Cerenkov interaction. In this work we derive (by using a fluid model) the relevant dispersion relation and the expression for the growth rate by solving the dispersion relation both analytically and numerically. Parametric studies show that the growth rate of the instability increases with the beam density. The instability is found to have the maximum growth rate when the perpendicular …