A graph that contains a spanning tree of diameter at most t clearly admits a tree t-spanner, since a tree t-spanner of a graph G is a sub tree of G such that the distance between pairs of vertices in the tree is at most t times their distance in G. In this paper, graphs that admit a tree t-spanner of diameter at most t + 1 are studied. For t equal to 1 or 2 the problem has been solved. For t = ...

The electrical properties of electrodeposited zinc‐copper‐telluride (ZnCuTe) nanowires embedded in polycarbonate track‐etch membrane (Whatman) having pore‐diameters of 200, 100 and 50nm have been studied and reported in this paper. Scanning electron microscopy (SEM) confirmed the formation of the nanowires of uniform diameter equal to the diameter of the templates used. ...

Given any n-gon of unit diameter in the plane, it is natural to inquire how large an area it can have. In 1922, Reinhardt [8] showed that for odd II, the obvious configuration is optimal, namely, among all n-gons of diameter 1, the regular n-gon has the maximum area. It was noted, however, that this is not the case for n even.l In particular, H. Lenz [7] raised the question of finding the large...

This article reviewed the literature regarding the diameter of dowels and identified three distinct philosophies of dowel space preparation. One group advocated the narrowest diameter for fabrication of a dowel to a desired length. Another recommended a dowel space with an apical diameter equal to one third of the narrowest dimension of the root at the terminus of the dowel. A third group advis...

An empirical equation from Riesz's classic study on difference thresholds is treated in a new manner. Reformulating the expression for the Weber fraction allows one to account for the shape of the loudness function at different frequencies. Furthermore, the emerging loudness function unifies both the commonly used power and logarithmic laws of sensation. In principle, equal loudness contours ca...

construction of forest roads disorders the natural trend of water movement. it is vital to make ditch and cross line drainage culvert to prevent the area from being destroyed and conduct the water of streems and vallies. determination of culvert diameters depends on the information of area discharge, physiographic characteristic, vegetation cover and site land use. in order to determine the amo...

Suppose we are given a solid of revolution generated by a conic section. Slice out a frustum of the solid [14, diagrams pp. 77, 80]. Then, construct a cylinder, with the same height as the frustum, whose diameter coincides with the diameter of the frustum at the midpoint of its height. What is the difference between the volume of the frustum and the volume of this cylinder? Does this difference...