ardy and Littlewood conjectured that every large integer $n$ that is not a square is the sum of a prime and a square. They believed that the number $mathcal{R}(n)$ of such representations for $n = p+m^2$ is asymptotically given by begin{equation*} mathcal{R}(n) sim frac{sqrt{n}}{log n}prod_{p=3}^{infty}left(1-frac{1}{p-1}left(frac{n}{p}right)right), end{equation*} where $p$ is a prime, $m$ is a...

a special class of cubic graphs are the cycle permutation graphs. a cycle permutation graph pn(α) is defined by taking two vertex-disjoint cycles on n vertices and adding a matching between the vertices of the two cycles.in this paper we determine a good upper bound for tenacity of cycle permutation graphs.

‎the objective of this paper is to obtain an upper bound to the second hankel determinant $|a_{2}a_{4}-a_{3}^{2}|$‎ ‎for the function $f$‎, ‎belonging to the class of gamma-starlike functions‎, ‎using toeplitz determinants‎. ‎the result presented here include‎ ‎two known results as their special cases‎.

‎A total dominating set of a graph $G$ is a set $D$ of vertices of $G$ such that every vertex of $G$ has a neighbor in $D$‎. ‎The total domination number of a graph $G$‎, ‎denoted by $gamma_t(G)$‎, ‎is~the minimum cardinality of a total dominating set of $G$‎. ‎Chellali and Haynes [Total and paired-domination numbers of a tree, AKCE International ournal of Graphs and Combinatorics 1 (2004)‎, ‎6...

Pressure vessel is a kind of special equipment which involved in various industries. Once it damaged, will cause great loss to people's life and property. The traditional elastic modulus reduction method for upper bound limit analysis pressure vessels adopts the elastic-perfectly plastic material model. This result waste materials without considering strain hardening effect. So effect introduce...

In this article we study graphs with ordering of vertices, define a generalization called pseudoordering, and for graph $H$ the $H$-Hamiltonian number $G$. We will show that concept is both Hamiltonian traceable number. prove equivalent characteristics an isomorphism $G$ using Furthermore, fixed each path has maximal upper number, which same claim numbers numbers. Finally every connected only p...

Twist extrusion process is a rather new route to produce highly strained materials. In this process, severe plastic deformation is applied by large shear strains. In current article, required energy for twist extrusion by use of admissible velocity field together with the upper bound technique is predicted. The proposed model is capable of considering the effect of various parameters such as di...

Deformation of the material during cyclic expansion extrusion (CEE) is investigated using upper-bound theorem. The analytical approximation of forming loads agrees very well with the FEM results for different amounts of chamber diameter, friction factor and also for lower die angles. However, the difference between analytical and numerical solution increases at higher die angles which are expla...

many metal forming problems have been solved using the slip line field method but all of them have either been two-dimensional (plane strain or plain stress) or axisymmetric problems. in this paper a procedure has been proposed by which the slip line field solution to three dimensional problems of metal forming becomes possible. for this purpose the extrusion of shaped sections has been taken a...