Let x, y be sets. Observe that {〈x, y〉} is one-to-one. In the sequel n denotes a natural number. One can prove the following two propositions: (1) For every non empty topological space T holds T and T ΩT are homeomorphic. (2) Let X be a non empty subspace of En T and f be a function from X into R1. Suppose f is continuous. Then there exists a function g from X into En T such that (i) for every ...

A finite non-empty word z is said to be a border of a finite non-empty word w if w = uz = zv for some non-empty words u and v. A finite non-empty word is said to be bordered if it admits a border, and it is said to be unbordered otherwise. In this paper, we give two characterizations of the biinfinite words of the form uvu, where u and v are finite words, in terms of its unbordered factors. The...

This study aims to investigate the effects of geometric imperfections on buckling of thin cylindrical shells due to global shear. To this end, more than 320 finite element models of cylindrical shells with different diameter to thickness ratios were prepared. Random imperfections with different amplitudes were applied to numerical models. The results revealed that global buckling of cylindrical...

Background: Marine pollution is a global environmental problem that its monitoring by ideal biomonitors is of great importance. Marine organisms, especially mussels, have the ability to accumulate metals from the environment they can be considered as a biomonitoring agent. Methods: In this study, concentrations of heavy metals were measured in Saccostrea cucullata collected from seven sites on...

The present study aims at investigating stress and deformation behavior of rotating thick truncated conical shells subjected to variable internal pressure. Material prpperties of the shells are graded along the axial direction by Mori-tanaka scheme, which is achieved by elemental gradation of the properties.Governing equations are derived using principle of stsionary total potential (PSTP) and ...

A parametric study was carried out in order to investigate the buckling capacity of the vertically stiffened cylindrical shells. To this end ANSYS software was used. Cylindrical steel shells with different yield stresses, diameter-to-thickness ratios (D/t) and number of stiffeners were modeled and their buckling capacities were calculated by displacement control nonlinear static analysis.  Radi...

This research was conducted to evaluate the possibility using peanut shells compost as a suitable medium in cultivating ornamental plants. Effect of peanut shells composts on the growth of Viola tricolor and marigold was investigated during seven months. Peat + perlite (with a ratio of 2:1) used as control treatment and peat replaced by 25, 50, 75 and 100 % v/v of peanut shells compost. Plant g...

This study aimed to investigate the effects of stiffeners on buckling of thin cylindrical shells under uniform axial compression. To this end, more than 300 finite element models of stiffened cylindrical shells were prepared. The variables considered are shell thickness, number, dimension and the location of the vertical and horizontal stiffeners as well as circular symmetrical imperfections. R...