The Zipoy-Voorhees family of static, axisymmetric vacuum solutions forms an interesting family in that it contains the Schwarzschild black hole excepting which all other members have naked singularity. We analyze some properties of the region near singularity by studying a natural family of 2-surfaces. We establish that these have the topology of the 2-sphere by an application of the Gauss-Bonn...

cotton/polyester knitted fabrics as a major production of textile industry was treated with titanium dioxide nanosized particles. the treated fabric with nanosized tio2 became whiter with a good self-cleaning property. also the discoloration of reactive black 5 dye was studied and reported. the stabilization of tio2 on cotton/polyester knitted fabrics by citric acid (ca) with sodium hypophospha...

the adsorption thermodynamic characteristic of cu2+ from aqueous solution onto humin andalso humic acid from a typical black soil in northeast china were examined at three different temperatures(298, 318 and 338 k) by batch isotherm experiments. results showed that humin was structurally differentfrom humic acid. the increase of temperature had a positive effect on the adsorption process. freun...

sooty blotch and flyspeck occur on fruit surfaces and result in economic losses due to less attractive appearance. sooty blotch fungi form dark mycelial mats whereas flyspeck fungal agents are well characterized with black, sclerotium-like bodies on fruit surface. whilst more than 60 species have been reported in association with these two fungal diseases, thus far they have not been studied in...

A very simple criterion to ascertain if (D − 2)-surfaces are trapped in arbitrary D-dimensional Lorentzian manifolds is given. The result is purely geometric, independent of the particular gravitational theory, of any field equations or of any other conditions. Many physical applications arise, a few shown here: a definition of general horizon, which reduces to the standard one in black holes/r...

We consider the application of stable marginally outer trapped surfaces to problems concerning the size of material bodies and the area of black holes. The results presented extend to general initial data sets (V, g,K) previous results assuming either maximal (trgK = 0) or time-symmetric (K = 0) initial data.

We study linear gravitational perturbations of Schwarzschild spacetime by solving numerically Regge-Wheeler-Zerilli equations in time domain using hyperboloidal surfaces and a compactifying radial coordinate. We stress the importance of including the asymptotic region in the computational domain in studies of gravitational radiation. The hyperboloidal approach should be helpful in a wide range ...

Radiatively inefficient (or advection dominated) disks are discussed at an introductory level. Ion supported and radiation supported flows are discussed, the different consequences of advection dominated flows onto black holes vs. solid surfaces (neutron stars, white dwarfs), hydrodynamics, the role of the ratio of specific heats, and the possible connection between ADAFs and outflows.

Black crusts on stone surfaces, mainly composed of gypsum crystals, not only aesthetically affect the stonework but also cause further decay. Appropriate conservation methods should nondestructively detect the pollutant type and extent. In this paper, we propose a computer aided diagnostic method for automatically detecting deterioration patterns on black crusts. The proposed non-destructive me...