Tayfun Aytaç Billur Barshan Bilkent University Department of Electrical Engineering Bilkent, TR-06800 Ankara, Turkey E-mail: [email protected] Abstract. We differentiate surfaces with different properties with simple low-cost IR emitters and detectors in a location-invariant manner. The intensity readings obtained with such sensors are highly dependent on the location and properties of t...

The question of whether an observer can escape from a black hole is addressed, using a recent general definition of a black hole in the form of a future outer trapping horizon. An observer on a future outer trapping horizon must enter the neighbouring trapped region. It is possible for the observer to subsequently escape from the trapped region. However, if the horizon separates the space-time ...

The microcanonical functional integral for an eternal black hole system is considered. This requires computing the microcanonical action for a spatially bounded spacetime region when its two disconnected timelike boundary surfaces are located in different wedges of the Kruskal diagram. The path integral is a sum over Lorentzian geometries and is evaluated semiclassically when its boundary data ...

We investigated how spatial pattern, background, and dynamic range affect perceived gloss in brightly lit real scenes. Observers viewed spherical objects against uniform backgrounds. There were three possible objects. Two were black matte spheres with circular matte white dots painted on them (matte-dot spheres). The third sphere was painted glossy black (glossy black sphere). Backgrounds were ...

It can be expected that the respective endpoints of the Gregory-Laflamme black brane instability and the Rayleigh-Plateau membrane instability are related because the bifurcation diagrams of the black hole-black string system and the liquid drop-liquid bridge system display many similarities. In this paper, we investigate the non-linear dynamics of the Rayleigh-Plateau instability in a range of...

Carbon black is a common polymer additive that is used for reinforcement and for its ability to enhance physical properties, such as conductivity. This article pertains to an X-ray scattering (SAXS) study of a conductive grade of carbon black and carbon black–polymer composites. The scattering pattern for such blacks displays a surface-fractal-like power-law decay over many decades in scatterin...

Accuracy of achromatic perceptions (correctly seeing blacks, grays, and whites) was investigated for three-dimensional rooms, painted matte black or white, presented empty or containing matte or specular, and black, middle gray, or white objects. The rooms were illuminated by a point source at various locations or by extended sources. Observers judged the achromatic color of four walls in the r...

A European campaign of ground-based radar, lidar and optical measurements was carried out during the winter of 1996/1997 (28 December±2 February) to study lee waves in the northern part of Scandinavia. The participants operated ozone lidars, backscatter lidars and MST radars at ALOMAR/Andoya and Esrange/Kiruna, and an ALIS imaging system in Kiruna. The Andoya site was generally windward of the ...

Abstract In this paper, we introduce the notion of a marginal tube, which is hypersurface foliated by surfaces. It generalises marginally trapped tube and several notions black hole horizons, for example trapping isolated dynamical etc. We prove that if every spacelike section surface, then null. There no assumption on topology tube. To it, study geometry surfaces in four-dimensional spacetime ...