Let G and H be graphs. A substitution of H in G instead of a vertex v 2 V (G) is the graph G(v ! H), which consists of disjoint union of H and G ? v with the additional edge-set fxy : x 2 V (H); y 2 N G (v)g. For a hereditary class of graphs P, the substitutional closure of P is deened as the class P consisting of all graphs which can be obtained from graphs in P by repeated substitutions. Let ...

It is argued that the prevailing definition of quasicrystals, requiring them to contain an axis of symmetry that is forbidden in periodic crystals, is inadequate. This definition is too restrictive in that it excludes an important and interesting collection of structures that exhibit all the well-known properties of quasicrystals without possessing any forbidden symmetries.

Abstract: Ore mineral characterization and various experimental testwork were carried out on Asian Abe-Garm dolomite, Qazvin province, Iran. The testwork consisted of calcining, chemical characterization, LOI determination, and reduction tests on the calcined dolomite (doloma), using Semnan ferrosilicon. Calcining of dolomite sample was carried out at about 1400 ºC in order to remove the contai...

Electrospinning was used to fabricate non-woven nanofibrous tubular scaffolds from Bombyx mori silk fibroin using an all aqueous process. Cell studies and mechanical characterization tests were performed on the electrospun silk tubes to assess the viability of their usage in bioengineering small-diameter vascular grafts. Human endothelial cells and smooth muscle cells were successfully cultured...

Microneedles, before being used for biomedical applications, have to satisfy biological and technical specifications, in particular they must guarantee a sufficient strength during exercise. Although studies on the mechanical characterization on single microneedles are reported in literature, microneedles must be arranged in matrices to be used in real biomedical applications. For these reasons...

A novel quantitative nano+micro-tribometer with integrated SPM and optical microscope imaging has been developed to characterize numerous physical and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests. Both the materials properties and surface t...