Search results for "Collapse"
showing 9 items of 159 documents
Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3a
2022
Abbott, R., et al. (LIGO and VIRGO Collaboration)
Inference of proto-neutron star properties from gravitational-wave data in core-collapse supernovae
2021
The eventual detection of gravitational waves from core-collapse supernovae (CCSN) will help improve our current understanding of the explosion mechanism of massive stars. The stochastic nature of the late post-bounce gravitational wave signal due to the non-linear dynamics of the matter involved and the large number of degrees of freedom of the phenomenon make the source parameter inference problem very challenging. In this paper we take a step towards that goal and present a parameter estimation approach which is based on the gravitational waves associated with oscillations of proto-neutron stars (PNS). Numerical simulations of CCSN have shown that buoyancy-driven g-modes are responsible …
Tell el-'Abd II. Pottery and Potmarks at an Early Urban Settlement of the Middle Euphrates River Valley, Syria. Final Reports of the Syrian-German ex…
2013
The monograph investigates the breakdown of the Uruk world-system towards the end of the 4th millennium BCE, and the roots of secondary state formation in the Middle Euphrates region through the analysis of continuity and change in the Early Bronze ceramic material from the site of Tell el-‘Abd (Tabqa Dam, Syria). This analysis fills a chronological gap for the early third millennium, a period poorly known in the district downstream from Carchemish. It further includes the study of over 1300 potter’s marks, thus offering new insight into the intra- and inter-site organization of pottery production and into a complex and variegated system of visual communication active at a regional level be…
Rotational effects on the oscillation frequencies of newly born proto-neutron stars
2003
In this paper we study the effects of rotation on the frequencies of the quasi-normal modes of a proto-neutron star (PNS) born in a gravitational collapse during the first minute of life. Our analysis starts a few tenths of seconds after the PNS formation, when the stellar evolution can be described by a sequence of equilibrium configurations. We use the evolutionary models developed by Pons et al. (1999; 2001) that describe how a non rotating star cools down and contracts while neutrino diffusion and thermalization processes dominate the stellar dynamics. For assigned values of the evolution time, we set the star into slow rotation and integrate the equations of stellar perturbations in th…
Evoluzione del comportamento idro-meccanico di una sabbia di quarzo dallo stato saturo allo stato asciutto
2022
La nota presenta i risultati di un lavoro sperimentale condotto con lo scopo di analizzare il comportamento idro-meccanico di una sabbia quarzosa per un ampio intervallo del grado di saturazione. Per analizzare le caratteristiche di ritenzione del materiale e per investigare la relazione tra la tensione di snervamento e la suzione di matrice sono state eseguite prove edometriche a suzione controllata e a contenuto d'acqua costante. I risultati ottenuti mostrano che la tensione di snervamento della sabbia non aumenta monotonamente con la suzione. Tale andamento è caratterizzato da un punto di massimo e da valori della tensione di snervamento sostanzialmente coincidenti per la condizioni satu…
VOLUMETRIC BEHAVIOUR OF SOILS EXPERIENCING WIDE CHANGES IN THE DEGREE OF SATURATION
2021
Remembering an Era: Roger Penrose’s Paper on “Gravitational Collapse: The Role of General Relativity”
2018
Back in the 1960s, Einstein’s theory of general relativity re-emerged as a field of important research activity. Much of the impetus behind this resurgence came from powerful new mathematical ideas that Roger Penrose and Stephen Hawking applied to prove general singularity theorems for global space-time structures. Their results stirred the imaginations of astrophysicists and gave relativistic cosmology an entirely new research agenda. A decade later, black holes and the big hang model were on the tongues of nearly everyone who followed recent trends in science. As popular expositions dealing with quasars, pulsars, and the geometry of black holes began to appear in magazines and textbooks, …
Alteration-Induced Volcano Instability at La Soufrière de Guadeloupe (Eastern Caribbean)
2021
International audience; Volcanoes are unstable structures that deform laterally and frequently experience mass wasting events. Hydrothermal alteration is often invoked as a mechanism that contributes significantly to volcano instability. We present a study that combines laboratory experiments, geophysical data, and large-scale numerical modeling to better understand the influence of alteration on volcano stability, using La Soufrière de Guadeloupe (Eastern Caribbean) as a case study. Laboratory experiments on variably altered (advanced argillic alteration) blocks show that uniaxial compressive strength, Young's modulus, and cohesion decrease as a function of increasing alteration, but that …
Rīcība ar vidi degradējošām, sagruvušām vai cilvēka drošību apdraudošām būvēm
2016
Maģistra darbā autore pēta administratīvi tiesisko ietvaru pašvaldības rīcībai ar vidi degradējošām, sagruvušām vai cilvēku drošību apdraudošām būvēm (graustiem). Lai panāktu būvju sakārtošanu, likumdevējs normatīvajos aktos pašvaldībai ir deleģējis tādus tiesiskos līdzekļus kā būves īpašnieka (tiesiskā valdītāja) administratīvā sodīšana, būves sakārtošana vai nojaukšana piespiedu kārtā, kā arī paaugstinātās nekustamā īpašuma nodokļa likmes piemērošana. Tomēr šo tiesisko līdzekļu realizācija praksē ir sarežģīta, dažādu iemeslu dēļ problemātiska vai neiespējama, kā rezultātā pašvaldība pienācīgi nevar nodrošināt tās iedzīvotāju tiesības dzīvot drošā un sakārtotā vidē. Pētījuma ietvaros tiek …