Search results for " black"
showing 10 items of 317 documents
Quantum Backreaction on Three-Dimensional Black Holes and Naked Singularities
2016
We analytically investigate backreaction by a quantum scalar field on two rotating Ba\~nados-Teitelboim-Zanelli (BTZ) geometries: that of a black hole and that of a naked singularity. In the former case, we explore the quantum effects on various regions of relevance for a rotating black hole space-time. We find that the quantum effects lead to a growth of both the event horizon and the radius of the ergosphere, and to a reduction of the angular velocity, compared to the unperturbed values. Furthermore, they give rise to the formation of a curvature singularity at the Cauchy horizon and show no evidence of the appearance of a superradiant instability. In the case of a naked singularity, we f…
Born–Infeld inspired modifications of gravity
2017
General Relativity has shown an outstanding observational success in the scales where it has been directly tested. However, modifications have been intensively explored in the regimes where it seems either incomplete or signals its own limit of validity. In particular, the breakdown of unitarity near the Planck scale strongly suggests that General Relativity needs to be modified at high energies and quantum gravity effects are expected to be important. This is related to the existence of spacetime singularities when the solutions of General Relativity are extrapolated to regimes where curvatures are large. In this sense, Born-Infeld inspired modifications of gravity have shown an extraordin…
A new chemical aid for criminal investigation: dyes and latent prints
2002
Criminalistics is a field in which there are many opportunities for the practical application of chemical reagents and the use of analytical methods that provide answers to enigmas at crime scenes. Common reagents in biochemical and medical test methods can be useful for criminalistics (forensic science). Dyes are one type of reagent that can be used in obtaining crime scene evidence. This work describes a new application of CI Solvent Black 3 dye in the location of latent fingerprints. The results show that CI Solvent Black 3 can be successfully applied in the location and development of recent and non-recent latent fingerprints on porous surfaces.
Il mare colore del sangue
2018
In their artwork "Calendoola: SURUS", visual artists Simone Trabucchi and Simone Bertuzzi AKA Invernomuto, in their characteristically visionary language combine sensory experiences and political urgency, offering a reflection on a potentially dystopian society incapable of coming to terms with its own history of colonial, imperial, neocolonial, and global domination. In their 2018 installation at the MAXXI Musuem in Rome, men bleed, turtles lie on their backs, and elephants look on, wise and inexorable. Meanwhile the sea is burning and has turned blood-red. It is the blood of the sons who cross it from opposite sides of the Mediterranean, some succeeding, others succumbing to its abysses. …
Lionello Perera: An Italian Banker and Patron in New York
2022
The book presents the long-lost biography of Lionello Perera, principal banker, patron, and philanthropist of the Italian American community in New York at the inception of the twentieth century. Born and raised in Venice, Lionello Perera took over his uncle’s financial activity in Wall Street and developed the family business into a stronghold of the Italian American community. His remarkable career led him to become the Vice President of Bank of America in 1928 as an associate of California born Amadeo P. Giannini, while he also was instrumental to the political success of New York mayor Fiorello La Guardia. Recognised as a true founding father of the Italian American community of the Eas…
Ierogamie, euritmie e ierotopie mariane in Sicilia. Il "case study" della Madonna dei Miracoli di Caltabellotta (Ag)
2021
Qual’è immagine venerata che resta come traccia mestica nella mente dei fedeli? Quella che tutto l’anno si può osservare sull’altare della chiesa o quella che solo una volta l’anno si può vedere durante la festa patronale? Partendo da queste domande in questo saggio si tracciano le origini di alcune raffigurazioni mariane siciliane, e in particolare del simulacro della Madonna del Soccorso o dei Miracoli di Caltabellotta (AG). È una ricerca ancora in nuce che propone una chiave di lettura dell’iconografia mariana inedita che partendo dall’analisi morfologica e iconografica, passando per la biologia delle immagini di warburghiana memoria, approda all’animismo e alla performance rituali. What…
Adsorption enrichment of some azo dye complexes on a carbon paste electrode and its application to the determination of small concentrations of cobal…
1974
The azo dyes eriochrome black T, eriochrome blueblack R and eriochrome blueblack B and their complexes with cobalt, manganese and magnesium show adsorption enrichment on carbon paste electrodes, dependent on the composition of the electrode filling. This effect may be used for the determination of cobalt and manganese by a.c. voltammetry in the 10−7 to 10−6 M range. Standard deviation has been found to be ± 3.2 and ± 3.5%, respectively.
First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
2019
The Event Horizon Telescope (EHT) has mapped the central compact radio source of the elliptical galaxy M87 at 1.3 mm with unprecedented angular resolution. Here we consider the physical implications of the asymmetric ring seen in the 2017 EHT data. To this end, we construct a large library of models based on general relativistic magnetohydrodynamic (GRMHD) simulations and synthetic images produced by general relativistic ray tracing. We compare the observed visibilities with this library and confirm that the asymmetric ring is consistent with earlier predictions of strong gravitational lensing of synchrotron emission from a hot plasma orbiting near the black hole event horizon. The ring rad…
Anomalous water diffusion in epoxy/carbon nanoparticle composites
2019
Abstract Water absorption-desorption-resorption and swelling were studied for a DGEBA-based amine-cured epoxy resin filled with four types of carbon nanoparticles: multiwall carbon nanotubes (MWCNT), graphite nano-platelets (GnP), expanded graphite platelets, and carbon black. Nanocomposites are characterised by lower diffusivity (down to 20% for epoxy/GnP) and increased water sorption capacity compared to the neat epoxy. Anomalous water absorption and swelling of nanocomposites is finely described by the diffusion-relaxation model. The relaxation times, considered as quantitative indicators of changes in segmental mobility of the polymer, increased with addition of nanoparticles and decrea…
Improvement of oxidation resistance of polymer-based nanocomposites through sonication of carbonaceous nanoparticles
2020
Abstract The work aim is focused on two different aspects: first, the investigation of the effect of extended ultra-sound-assisted treatment (us) of carbonaceous nanoparticles, such as carbon nanotubes (CNTs) and carbon black (CB), on their radical scavenging activity, and second, the investigation of the oxidative resistance of polymer-based nanocomposites, containing us-treated CNTs and CB. Particularly, the CNTs and CB have been subjected to us sonication for different time intervals and the performed analysis reveals that both kinds of nanoparticles show decreased average hydrodynamic diameters and large content of surface defects. Really, the increased content of CNTs and CB defects, a…