http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2009/524307.htmlWe consider the application of a new analytic method based on homotopy analysis to the solution of the steady flow of a viscous incompressible fluid past a fixed circular cylinder. The solutions obtained using this method produce some interesting results. For instance, an analytic verification of the critical Reynolds number Rd for which a standing vortex first appears behind the cylinder is given for the first time and found to be Rd≼2.4. Since these values of the critical Reynolds number are beyond the range of validity of Oseen theory, no analytic verification of this value had previously been given. As a check on the accuracy of the solutions, the calculated drag coefficients at 6th-order approximation are found to agree reasonably well with experimental measurements for Rd≃30 which is considerably larger than the Rd≃1 results currently available using other analytic techniques. This buttresses the usefulness of the homotopy analysis method (HAM) as an important tool in solving highly nonlinear problems.E. O. Ifidon© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/753518.htmlWe obtain some conditions under which the positive solution for semidiscretizations of the semilinear equation ut=uxx−a(x,t)f(u),  0<x<1,  t∈(0,T), with boundary conditions ux(0,t)=0, ux(1,t)=b(t)g(u(1,t)), blows up in a finite time and estimate its semidiscrete blow-up time. We also establish the convergence of the semidiscrete blow-up time and obtain some results about numerical blow-up rate and set. Finally, we get an analogous result taking a discrete form of the above problem and give some computational results to illustrate some points of our analysis.Louis A. Assalé, Théodore K. Boni, and Diabate Nabongo© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2009/150420.htmlWe consider the uniform attractors for the two dimensional nonautonomous g-Navier-Stokes equations in bounded domain Ω. Assuming f=f(x,t)∈Lloc2, we establish the existence of the uniform attractor in L2(Ω) and D(A1/2). The fractal dimension is estimated for the kernel sections of the uniform attractors obtained.Delin Wu© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/586567.htmlThe velocity induced by a plane, uniform vortex is investigated through the use of an integral relation between Schwarz function of the vortex boundary and conjugate of the velocity. The analysis is restricted to a certain class of vortices, the boundaries of which are described through conformal maps onto the unit circle and the corresponding Schwarz functions possess two poles in the plane of the circle. The dependence of the velocity field on the vortex shape is investigated by comparing velocity and streamfunction with the ones of the equivalent Rankine vortex (which has the same vorticity, area, and center of vorticity). By changing the parameters of the Schwarz function (poles and corresponding residues), rather complicated vortex shapes can be easily analyzed, some of them mimicing an incipient filamentation of the vortex boundary.G. Riccardi and D. Durante© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/640154.htmlThe obesity epidemic is considered a health concern of paramount importance in modern society. In this work, a nonstandard finite difference scheme has been developed with the aim to solve numerically a mathematical model for obesity population dynamics. This interacting population model represented as a system of coupled nonlinear ordinary differential equations is used to analyze, understand, and predict the dynamics of obesity populations. The construction of the proposed discrete scheme is developed such that it is dynamically consistent with the original differential equations model. Since the total population in this mathematical model is assumed constant, the proposed scheme has been constructed to satisfy the associated conservation law and positivity condition. Numerical comparisons between the competitive nonstandard scheme developed here and Euler's method show the effectiveness of the proposed nonstandard numerical scheme. Numerical examples show that the nonstandard difference scheme methodology is a good option to solve numerically different mathematical models where essential properties of the populations need to be satisfied in order to simulate the real world.Rafael J. Villanueva, Abraham J. Arenas, and Gilberto González-Parra© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/570825.htmlWe carry out the effect of the induced magnetic field on peristaltic transport of an incompressible conducting micropolar fluid in a symmetric channel. The flow analysis has been developed for low Reynolds number and long wavelength approximation. Exact solutions have been established for the axial velocity, microrotation component, stream function, magnetic-force function, axial-induced magnetic field, and current distribution across the channel. Expressions for the shear stresses are also obtained. The effects of pertinent parameters on the pressure rise per wavelength are investigated by means of numerical integrations, also we study the effect of these parameters on the axial pressure gradient, axial-induced magnetic field, as well as current distribution across the channel and the nonsymmetric shear stresses. The phenomena of trapping and magnetic-force lines are further discussed.Kh. S. Mekheimer© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/414830.htmlThis study sought to investigate thermal radiation and buoyancy effects on heat and mass transfer over a semi-infinite stretching surface with suction and blowing. Appropriate transformations were employed to transform the governing differential equations to nonsimilar form. The transformed equations were solved numerically by an efficient implicit, iterative finite-difference scheme. A parametric study illustrating the influence of wall suction or injection, radiation, Schmidt number and Grashof number on the fluid velocity, temperature and concentration is conducted. We conclude from the study that the flow is appreciably influenced by thermal radiation, Schmidt number, as well as fluid injection or suction.S. Shateyi© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/835380.htmlThe study sought to investigate thermosolutal convection and stability of two dimensional disturbances imposed on a heated boundary layer flow over a semi-infinite horizontal plate composed of a chemical species using a self-consistent asymptotic method. The chemical species reacts as it diffuses into the nearby fluid causing density stratification and inducing a buoyancy force. The existence of significant temperature gradients near the plate surface results in additional buoyancy and decrease in viscosity. We derive the linear neutral results by analyzing asymptotically the multideck structure of the perturbed flow in the limit of large Reynolds numbers. The study shows that for small Damkohler numbers, increasing buoyancy has a destabilizing effect on the upper branch Tollmien-Schlichting (TS) instability waves. Similarly, increasing the Damkohler numbers (which corresponds to increasing the reaction rate) has a destabilizing effect on the TS wave modes. However, for small Damkohler numbers, negative buoyancy stabilizes the boundary layer flow.Stanford Shateyi, Precious Sibanda, and Sandile S. Motsa© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/576783.htmlWe use the geometric notion of a differential system describing surfaces of a constant negative curvature and describe a family of pseudospherical surfaces for the KdV-Burgers-Kuramoto and nonlinear Schrödinger equations with constant Gaussian curvature −1. Travelling wave solutions for the above equations are obtained by using a sech-tanh method and Wu's elimination method.S. M. Sayed, O. O. Elhamahmy, and G. M. Gharib© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/124269.htmlWe study the robustness of strong stability of the homogeneous difference equation via the concept of strong stability radii: complex, real and positive radii in this paper. We also show that in the case of positive systems, these radii coincide. Finally, a simple example is given.The Anh Bui and Dang Xuan Thanh Duong© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/846282.htmlThe present paper is the first in a series of works devoted to the solvability of the Possio singular integral equation. This equation relates the pressure distribution over a typical section of a slender wing in subsonic compressible air flow to the normal velocity of the points of a wing (downwash). In spite of the importance of the Possio equation, the question of the existence of its solution has not been settled yet. We provide a rigorous reduction of the initial boundary value problem involving a partial differential equation for the velocity potential and highly nonstandard boundary conditions to a singular integral equation, the Possio equation. The question of its solvability will be addressed in our forthcoming work.A. V. Balakrishnan and M. A. Shubov© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/528934.htmlThe well-known root-locus method is developed for special subset of linear time-invariant systems known as fractional-order systems. Transfer functions of these systems are rational functions with polynomials of rational powers of the Laplace variable s. Such systems are defined on a Riemann surface because of their multivalued nature. A set of rules for plotting the root loci on the first Riemann sheet is presented. The important features of the classical root-locus method such as asymptotes, roots condition on the real axis, and breakaway points are extended to fractional case. It is also shown that the proposed method can assess the closed-loop stability of fractional-order systems in the presence of a varying gain in the loop. Three illustrative examples are presented to confirm the effectiveness of the proposed algorithm.Farshad Merrikh-Bayat and Mahdi Afshar© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/354652.htmlWe construct an exponential attractor for a first-order dissipative lattice dynamical system arising from spatial discretization of reaction-diffusion equations in ℝk. And we obtain fractal dimension of the exponential attractor.Xiaoming Fan© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/639145.htmlBy means of the notion of likelihood ratio, the limit properties of the sequences of arbitrary-dependent continuous random variables are studied, and a kind of strong limit theorems represented by inequalities with random bounds for functions of continuous random variables is established. The Shannon-McMillan theorem is extended to the case of arbitrary continuous information sources. In the proof, an analytic technique, the tools of Laplace transform, and moment generating functions to study the strong limit theorems are applied.Gaorong Li, Shuang Chen, and Sanying Feng© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/537284.htmlA class of time-delay reaction-diffusion systems with variable coefficients which arise from the model of two competing ecological species is discussed. An asymptotic global attractor is established in terms of the variable coefficients, independent of the time delays and the effect of diffusion by the upper-lower solutions and iteration method.Miguel Uh Zapata, Eric Avila Vales, and Angel G. Estrella© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/190836.htmlA Markov chain approach to the study of randomly grown graphs is proposed and applied to some popular models that have found use in biology and elsewhere. For most randomly grown graphs used in biology, it is not known whether the graph or properties of the graph converge (in some sense) as the number of vertices becomes large. Particularly, we study the behaviour of the degree sequence, that is, the number of vertices with degree 0,1,…, in large graphs, and apply our results to the partial duplication model. We further illustrate the results by application to real data.Michael Knudsen and Carsten Wiuf© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2008/453627.htmlA class of fuzzy Cohen-Grossberg neural networks with distributed delay and variable coefficients is discussed. It is neither employing coincidence degree theory nor constructing Lyapunov functionals, instead, by applying matrix theory and inequality analysis, some sufficient conditions are obtained to ensure the existence, uniqueness, global attractivity and global exponential stability of the periodic solution for the fuzzy Cohen-Grossberg neural networks. The method is very concise and practical. Moreover, two examples are posed to illustrate the effectiveness of our results.Hongjun Xiang and Jinde Cao© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/015745.abs.htmlThis paper is concerned with the nonlinear theory of micropolar, porous, and elastic solids. By using the theory of Langenbach, within this context, we obtain some existence and uniqueness results.Marin Marin© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/012375.abs.htmlThe purpose of this paper is the construction of invariant regions in which we establish the global existence of solutions for reaction-diffusion systems (three equations) with a tridiagonal matrix of diffusion coefficients and with nonhomogeneous boundary conditions after the work of Kouachi (2004) on the system of reaction diffusion with a full 2-square matrix. Our techniques are based on invariant regions and Lyapunov functional methods. The nonlinear reaction term has been supposed to be of polynomial growth.Abdelmalek Salem© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/056360.abs.htmlThe three-dimensional linearized theory of elastodynamics mathematical formulation of the forced vibration of a prestretched plate resting on a rigid half-plane is given. The variational formulation of corresponding boundary-value problem is constructed. The first variational of the functional in the variational statement is equated to zero. In the framework of the virtual work principle, it is proved that appropriate equations and boundary conditions are derived. Using these conditions, finite element formulation of the prestretched plate is done. The numerical results obtained coincide with the ones given by Ufly and in 1963 for the static loading case.M. Eröz and A. Yildiz© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/026075.abs.htmlWe extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated with homogeneous difference equations. Finally, the result obtained is applied to derive necessary and sufficient conditions for the stability of positive system.Bui The Anh and D. D. X. Thanh© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/051905.abs.htmlCutting tests were conducted to medium carbon steel using HSS tools with cutting fluid. The experimental design used was based on response surface methodology (RSM) using a central composite design. Chips were collected at different machining conditions and thickness and microhardness measurements taken and analyzed using “DESIGN EXPERT 7” experimental design software. Mathematical models of the responses (thickness and microhardness) as functions of the conditions (speed, feed, and depth of cut) were obtained and studied. The resultant second-order models show chip thickness increases when increasing feed and speed, while increasing depth of cut resulted in a little effect on chip thickness. Chip microhardness increases with increasing depth of cut. It also increases with increasing speed and feed up to a certain level beyond which further increases cause a drop in microhardness.S. A. Alrabii and L. Y. Zumot© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/062098.abs.htmlWe show that the problem of recovering the time-dependent parameters of an equation of Black-Scholes type can be formulated as an inverse Stieltjes moment problem. An application to the problem of implied volatility calculation in the case when the model parameters are time varying is provided and results of numerical simulations are presented.Marianito R. Rodrigo and Rogemar S. Mamon© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/080205.abs.htmlAs is well known, submerged horizontal cylinders can serve as waveguides for surface water waves. For large values of the wavenumber k in the direction of the cylinders, there is only one trapped wave. We construct asymptotics of these trapped modes and their frequencies as k→∞ in the case of one or two submerged cylinders by means of reducing the initial problem to a system of integral equations on the boundaries and then solving them using a technique suggested by Zhevandrov and Merzon (2003).A. M. Marín, R. D. Ortíz, and P. Zhevandrov© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/024238.abs.htmlWe propose a mixed formulation in dynamical elasticity of shells which allows a locking-free finite element approximation in particular cases of Koiter shells.Saloua Mani Aouadi© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/097540.abs.htmlThe main objective of the paper is to analyze the effects on economic agents' behavior deriving from the introduction of financial activities aimed to environmental protection. The environmental protection mechanism we study should permit exchange of financial activities among citizens, firms, and Public Administration. Such a particular “financial market” is regulated by the Public Administration, but mainly fuelled by the interest of two classes of involved agents: firms and dwelling citizens. We assume that the adoption process of financial decisions is described by a two-population evolutionary game and we study the basic features of the resulting dynamics.Angelo Antoci, Marcello Galeotti, and Lucio Geronazzo© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/031572.abs.htmlWe prove existence theorems for the integrodifferential equation x'(t)=f(t,x(t),∫0tk(t,s, x(s))ds), x(0)=x0, t∈Ia=[0,a], a>0, where f,k,x are functions with values in a Banach space E and the integral is taken in the sense of HL. Additionally, the functions f and k satisfy certain boundary conditions expressed in terms of the measure of noncompactness.Aneta Sikorska-Nowak© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/032824.abs.htmlThe primary functions of a bank are to obtain funds through deposits from external sources and to use the said funds to issue loans. Moreover, risk management practices related to the withdrawal of these bank deposits have always been of considerable interest. In this spirit, we construct Lévy process-driven models of banking reserves in order to address the problem of hedging deposit withdrawals from such institutions by means of reserves. Here reserves are related to outstanding debt and acts as a proxy for the assets held by the bank. The aforementioned modeling enables us to formulate a stochastic optimal control problem related to the minimization of reserve, depository, and intrinsic risk that are associated with the reserve process, the net cash flows from depository activity, and cumulative costs of the bank's provisioning strategy, respectively. A discussion of the main risk management issues arising from the optimization problem mentioned earlier forms an integral part of our paper. This includes the presentation of a numerical example involving a simulation of the provisions made for deposit withdrawals via treasuries and reserves.F. Gideon, J. Mukuddem-Petersen, and M. A. Petersen© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/038278.abs.htmlA class of coupled system of diffusion equations is considered. Lie group techniques resulted in a rich array of admitted point symmetries for special cases of the source term. We also employ potential symmetry methods for chosen cases of concentration and a zero source term. Some invariant solutions are constructed using both classical Lie point and potential symmetries.Raseelo J. Moitsheki© 2009, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/jam/2007/029343.abs.htmlWe study the stochastic dynamics of banking items such as assets, capital, liabilities and profit. A consideration of these items leads to the formulation of a maximization problem that involves endogenous variables such as depository consumption, the value of the bank's investment in loans, and provisions for loan losses as control variates. A solution to the aforementioned problem enables us to maximize the expected utility of discounted depository consumption over a random time interval, [t,τ], and profit at terminal time τ. Here, the term depository consumption refers to the consumption of the bank's profits by the taking and holding of deposits. In particular, we determine an analytic solution for the associated Hamilton-Jacobi-Bellman (HJB) equation in the case where the utility functions are either of power, logarithmic, or exponential type. Furthermore, we analyze certain aspects of the banking model and optimization against the regulatory backdrop offered by the latest banking regulation in the form of the Basel II capital accord. In keeping with the main theme of our contribution, we simulate the financial indices return on equity and return on assets that are two measures of bank profitability.J. Mukuddem-Petersen, M. A. Petersen, I. M. Schoeman, and B. A. Tau© 2009, Hindawi Publishing Corporation. All rights reserved.