This research presents adsorption potential of surfactant (sodium dodecyl sulphate; SDS) coated magnetite nanoparticles as suitable and efficient adsorbent for the removal of Basic Blue 41 (BB 41), as a cationic dye from textile’s company wastewater. The effects of various experimental parameters (e.g. initial pH of the solution, SDS amount, and ionic strength) on the adsorption efficiency of B...

This article analyzes a strongly nonlinear oscillator with cubic and harmonic restoring force and proposes an efficient analytical technique based on the modified energy balance method (MEBM). The proposed method incorporates higher-order approximations. After applying the proposed MEBM, a set of complicated higher-order nonlinear algebraic equations are obtained. Higher-order nonlinear algebra...

An efficient formulation for the robust shape optimization of aerodynamic objects is introduced in this paper. The formulation has three essential features. First, an Euler solver based on a second-order Godunov scheme is used for the flow calculations. Second, a genetic algorithm with binary number encoding is implemented for the optimization procedure. The third ingredient of the procedure is...

Consider the hyperbolic system of conservation laws ut + F (u)x = 0. Let u be the unique viscosity solution with initial condition u(0, x) = ū(x), and let u be an approximate solution constructed by the Glimm scheme, corresponding to the mesh sizes ∆x, ∆t = O(∆x). With a suitable choice of the sampling sequence, we prove the estimate ∥∥uG(t, ·)− u(t, ·)∥∥ L1 = o(1) · √ ∆x ∣∣ ln(∆x)∣∣.

Several recent papers propose competing theoretical explanations for the empirical observation of an inverted U-shape relationship between enviromental degradation and per-capita income. We proprose the following test of the theory: calibrate a theoretical model to an already developed economy using information unrelated to the pollution-income curve. Then simulate the model starting from a les...

Sharp temporal decay estimates are established for the gradient and time derivative of solutions to the Hamilton-Jacobi equation ∂tvε + H(|∇xvε|) = ε ∆vε in R × (0,∞), the parameter ε being either positive or zero. Special care is given to the dependence of the estimates on ε. As a by-product, we obtain convergence of the sequence (vε) as ε → 0 to a viscosity solution, the initial condition bei...

The shape optimization of gravity dam is posed as an optimization problem with goals of minimum value of concrete, stresses and maximum safety against overturning and sliding need to be achieved. Optimally designed structure generally saves large investments especially for a large structure. The size of hydraulic structures is usually huge and thus requires a huge investment. If the optimizatio...

We consider the following evolutionary Hamilton-Jacobi equation with initial condition: { ∂tu(x, t) +H(x, u(x, t), ∂xu(x, t)) = 0, u(x, 0) = φ(x). Under some assumptions on H(x, u, p) with respect to p and u, we provide a variational principle on the evolutionary Hamilton-Jacobi equation. By introducing an implicitly defined solution semigroup, we extend Fathi’s weak KAM theory to certain more ...