فهرست مطالب
 Volume:7 Issue:1, 2016
 تاریخ انتشار: 1394/11/10
 تعداد عناوین: 11


Pages 19In this paper, we determine the degree distance of the complement of arbitrary Mycielskian graphs. It is well known that almost all graphs have diameter two. We determine this graphical invariant for the Mycielskian of graphs with diameter two.Keywords: Degree distance, Zagreb indices, Mycielskian

Pages 1117The vertexedge Wiener index of a simple connected graph G is defined as the sum of distances between vertices and edges of G. Two possible distances D_1(u,eG) and D_2(u,eG) between a vertex u and an edge e of G were considered in the literature and according to them, the corresponding vertexedge Wiener indices W_{ve_1}(G) and W_{ve_2}(G) were introduced. In this paper, we present exact formulas for computing thevertexedge Wiener indices of two composite graphs named splice and link.Keywords: Distance in graph, vertex, edge Wiener index, splice, link

Pages 1927In this paper operational matrix of Bernstein Polynomials (BPs) is used to solve Bratu equation. This nonlinear equation appears in the particular elecotrospun nanofibers fabrication process framework. Elecotrospun organic nanofibers have been used for a large variety of filtration applications such as in nonwoven and filtration industries. By using operational matrix of fractional integration and multiplication the investigated equations are turned into set of algebraic equations. Numerical solutions show both accuracy and simplicity of the suggested approach.Keywords: Bratu equation, Elecotrospun nanofibers, Bernstein polynomials, Operational matrix

Pages 2938Let $G$ be a molecular graph with vertex set $V(G)$, $d_G(u, v)$ the topological distance between vertices $u$ and $v$ in $G$. The Hosoya polynomial $H(G, x)$ of $G$ is a polynomial $sumlimits_{{u, v}subseteq V(G)}x^{d_G(u, v)}$ in variable $x$. In this paper, we obtain an explicit analytical expression for the expected value of the Hosoya polynomial of a random benzenoid chain with $n$ hexagons. Furthermore, as corollaries, the expected values of the wellknown topological indices: Wiener index, hyperWiener index and TratchStankevitchZefirov index of a random benzenoid chain with $n$ hexagons can be obtained by simple mathematical calculations, which generates the results given by I. Gutman et al. [Wiener numbers of random benzenoid chains, Chem. Phys. Lett. 173 (1990) 403408].Keywords: Wiener index, Random benzenoid chain, Hosoya polynomial, Expected value, Generating function

Pages 3946The idea of “forcing” has long been used in many research fields, such as colorings, orientations, geodetics and dominating sets in graph theory, as well as Latin squares, block designs and Steiner systems in combinatorics (see [1] and the references therein). Recently, the forcing on perfect matchings has been attracting more researchers attention. A forcing set of M is a subset of M contained in no other perfect matchings of G. A global forcing set of G, introduced by Vukiˇcevi´c et al., is a subset of E(G) on which there are distinct restrictions of any two different perfect matchings of G. Combining the above “forcing” and “global” ideas, Xu et al. [5] introduce and define a complete forcing set of G as a subset of E(G) on which the restriction of any perfect matching M of G is a forcing set of M. The minimum cardinality of complete forcing sets is the complete forcing number of G. In this paper, we give the explicit expressions for the complete forcing number of several classes of polyphenyl systems.Keywords: complete forcing number, polyphenly system, global forcing number

Pages 4759A quantitative structureactivity relationship (QSAR) study was conducted for the prediction of inhibitory activity of 1phenyl[2H]tetrahydrotriazine3one analogues as inhibitors of 5Lipoxygenase. The inhibitory activities of the 1phenyl[2H]tetrahydrotriazine3one analogues modeled as a function of molecular structures using chemometrics methods such as multiple linear regression (MLR) and least squares support vector machines (LSSVM). The obtained models were applied to predict the inhibitory activity of compounds which were not in the modeling procedure. The results of models showed high prediction ability with root mean square error of prediction of 0.167 and 0.061 for MLR and LSSVM, respectively. The LSSVM method was used for prediction of inhibitory activity of the new inhibitor derivatives.Keywords: QSAR, 1, phenyl[2H], tetrahydro, triazine, 3, oneanalogues, MLR, LS, SVM

Pages 6168The Harary index H can be viewed as a molecular structure descriptor composed of increments representing interactions between pairs of atoms, such that their magnitude decreases with the increasing distance between the respective two atoms. A generalization of the Harary index, denoted by Hk, is achieved by employing the Steinertype distance between ktuples of atoms. We show that the linear combination H+x H3 is significantly better correlated with a variety of physicochemical properties of alkanes than H itself.Keywords: Harary index, multicenter Harary index, Steiner distance, molecular graph

Pages 6975Integrally skinned asymmetric membranes based on nanocompositepolyethersulfone were prepared by the phase separation process using the supercritical CO2 as a nonsolvent for the polymer solution. In present study, the effects of temperature and nanoparticle on selectivity performance and permeability of gases has beeninvestigated. It is shown that the presence of silica nanoparticles not only disrupts the original polymer chain packing but also alters the chemical affinities of penetrants in polyethersulfone matrices. Because, in the presence of hydrophilic silica, CO2 affinity filler, hydrogenbond interactions between the oxygen atoms of carbon dioxide and the hydrogen atoms of hydroxyl group on the nanosilica surface would take place at the interface and thus solubility and consequently permeability towards CO2 are higher in comparison with CH4 for the membranes. Furthermore, in present study, a novel mathematical approach has been proposed to develop a model for permeation flux and selectivity performance of the membrane using Support Vector Machine. SVM is employed to develop a model toestimateprocess output variables of a nanocomposite membrane including permeation flux and selectivity performance. Model development that consists of training, optimization and test was performed using randomly selected 80%, 10%, and 10% of available data respectively.Keywords: Nanocomposite material • polyerthersulfone membrane • silica nanoparticles • Support Vector Machine (SVM)

Pages 7788In this article using the inverse Laplace transform, we show analytical solutions for the generalized mass transfers with (and without) a chemical reaction. These transfers have been expressed as the Couette flow with the fractional derivative of the Caputo sense. Also, using the Hankel contour for the Bromwich's integral, the solutions are given in terms of the generalized Airy functions.Keywords: Lévêque Problem, Laplace transform, Generalized Airy functions, Fractional derivative

Pages 8992In this paper, the Hyper  Zagreb index of the Cartesian product, composition and corona product of graphs are computed. These corrects some errors in G. H. Shirdel et al.[11].Keywords: Hyper, Zagreb index, Zagreb index, graph operation

Pages 93110QSPR study on benzene derivatives have been made using recently introduced topological methodology. In this study the relationship between the Randic' (x'), Balaban (J), Szeged (Sz),Harary (H), Wiener (W), HyperWiener and Wiener Polarity (WP) to the thermal energy (Eth), heat capacity (CV) and entropy (S) of benzene derivatives is represented.Physicochemical properties are taken from the quantum mechanics methodology with HF level using the ab initio 631G basis sets. The multiple linear regressions (MLR) and back ward methods (with significant at the 0.05 level) were employed to give the QSPR models.The satisfactory obtained results show that combining the two descriptors (Sz, HW) are useful topological descriptors for predicted (CV) and (S) of the 45 benzene derivatives.The training set models established by MLR method have not good correlation of (Eth), which means QSPR models could not predict the thermal energy of compounds.Keywords: QSPR, Topological indices, benzene derivatives, Graph theory, Multiple linear regressions (MLR)