The diameter of a set P of n points in R is the maximum Euclidean distance between any two points in P . If P is the vertex set of a 3-dimensional convex polytope, and if the combinatorial structure of this polytope is given, we prove that, in the worst case, deciding whether the diameter of P is smaller than 1 requires Ω(n log n) time in the algebraic computation tree model. It shows that the ...

Let n be a positive integer, and λ > 0 a real number. Let Vn be a set of n points randomly located within the unit disk, which are mutually independent. For 1 ≤ p ≤ ∞, define Gp(λ, n) to be the graph with the vertex set Vn, in which two vertices are adjacent if and only if their `p-distance is at most λ. We call this graph a unit disk random graph. Let λ = c √ ln n/n and let X be the number of ...

homogeneity and uniformity of soil particles is a most potent factor which affects soil spectral signatures. geometric standard deviation of soil particles (?g) exhibits the homogeneity of soil components. this study presents the influence of ?g on spectral studying of soil geometric mean particle diameter as well as lime. the study was conducted in pol-e-dokhtar using the data set of lissiii-p...

The rehabilitation of sandy desertified land in various dryland ecosystems by different management practices has a great potential to increase aggregate stability and improve soil quality. However, plants in general may have a different ability to sustain soil. The objective was to determine the effects of reclamation practices including Haloxylon ammodendron and Atriplex canescens plantation o...

the geometric mean particle diameter (dg) and lime are two of the most important properties from the viewpoint of soil management. nowadays remote sensing technology which has emerged walking with science development throughout the world, has made soil study faster, more facile and more cost-efficient. an investigation of soil dg and lime was performed in pol-e-dokhtar area by use of four sets ...

physical properties are often required for designing post harvest handling and processing equipment for agricultural products. persimmon (khormandy cultivar) is rich in vitamin a, calcium, potassium, tannic acid and antioxidant phenolic compounds. in this study changes in the physical properties of persimmon fruit during storage were studied. properties such as fruit dimensions, mass, geometric...

Fe-Cr-Al alloy nanopowders were successfully prepared by electrical wire explosion method in ethyl alcohol media. The formation of FeCr-Al alloy nanopowder was monitored by X-ray diffraction. The alloy powders have spherical shape and nanometer size. The alloy powders prepared by the electrical wire explosion method have main crystal structures of bcc Fe-Cr alloy. The geometric mean diameter an...

This study presents measurements of size and time-resolved particle diameter growth rates for freshly nucleated particles down to 1 nm geometric diameter. Novel data analysis methods were developed, de-coupling for the first time the size and time-dependence of particle growth rates by fitting the aerosol general dynamic equation to size distributions obtained at an instant in time. Size distri...

safflower is a strategic plant regarding to its valuable nutrition value (45% extractable oil) and industrial uses. due to massive import of edible oil to the country as well as high potential for safflower cultivation, the research on production of safflower for oil extrusion purpose is of remarkable importance. the design of various processing and oil extraction units and also their optimizat...