In this study, at first step nanopowder particles of  α-Fe2O3 (Hematite) and  Co3O4 were synthesized separately thorough simple chemical method from an aqueous solution of iron (III) nitrate nonahydrate (Fe(NO3)3.9H2O) and cobalt (II) hexahydrate (Co(NO3)2.6H2O) as  precursors.  After that, three composites nanopowders Fe2O3 with 8, 16 24 wt.% prepared. Graphite was added to one composition sam...

TiCl4, ammonia, inorganic salts as raw material, nanometer composite-crystal TiO2 powders were synthesized by two-step chemical method. Precursors were crystallized with different phase and stable composite-crystal TiO2 with anatase and rutile phase was prepared at low temperature. Quantitative control of crystal phase was realized. Remarkable factors includ...

We propose a unified framework to study the walk problem in a polygonal area by two collaborative guards. A walk is conducted by the two mobile guards on the area’s boundary. They start at an initial boundary point, move along the boundary, and may possibly meet together again at an ending boundary point. It is required that the two guards maintain their mutual visibility at all times. Dependin...

A review of methods for volumetric scene reconstruction from multiple views is presented. Occupancy descriptions of the voxels in a scene volume are constructed using shape-from-silhouette techniques for binary images, and shapefrom-photo-consistency combined with visibility testing for color images.

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Inspired by the recent Democratic National Primary, we consider settings in which the members of a distributed population must balance their individual preferences over candidates with a requirement to quickly achieve collective unity. We formalize such settings as the “Democratic Primary Problem” (DPP) over an undirected graph, whose local structure models the social influences acting on

In one of his early papers Claude Berge proved a Helly-type theorem, which replaces the usual “nonempty intersection” condition with a “convex union” condition. Inspired by this we prove a fractional Helly-type result, where we assume that many (d+1)-tuples of a family of convex sets have a star-shaped union, and the conclusion is that many of the sets have a common point. We also investigate s...

This paper discusses evaluation in the context of public art and specifically of interactive digital art. The study reported is of ‘Light Logic’, an exhibition of retrospective and current drawings, paintings and interactive digital works by the second author. The study was conducted by Site Gallery Sheffield in association with UK and Australian researchers. A survey of evaluation practice amo...

in recent years, the effects of heterogeneous catalysts for the oxidation of organic and inorganic pollutants in industrial wastewaters are spread. traditionally, these reactions are usually carried out using suspensions of photo-catalysts such as tio2. a chemical method including ticl4, al(no3)3, ethanol amine, ethyl acetoacetate and aqueous ammonia were used for the fabrication of tio2-al2o3 ...