Volume 15, Issue 3-4

The steady stagnation point flow of Jeffrey nanofluid over an exponential stretching surface under the boundary layer assumptions is discussed analytically. The transport equations include the effects of Brownian motion and thermophoresis. The boundary layer coupled partial differential equations of Jeffrey nanofluid are simplified with the help of suitable semi-similar transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions have been discussed by plotting h-curve. The expressions for velocity, temperature and nano particle volume fraction are computed for some values of the parameters namely, Jeffrey relaxation and retardation parameters B and λ 1 , stretching/ shrinking parameter A , suction injection parameter v w , Lewis number Le , the Brownian motion Nb , thermophoresis parameter Nt and Prandtl number Pr .

This paper proposes an adaptive neural network based control scheme for coordinated multiple mobile manipulators in the presence of model uncertainties and external disturbances. A key feature of this scheme is that the prior information of the possible upper bound of the uncertainty is not required. A feedforward neural network (FFNN) is employed to learn this upper bound. The proposed controller not only achieves uniformly ultimate boundedness (UUB) for trajectory tracking error of the object but also keeps the internal force error under a bound. Simulation studies are carried out for coordinated two wheels driven mobile manipulators.

For the reliability evaluation of a complex system, the aleatory uncertainty and epistemic uncertainty always exist at the same time because of the inadequate experimental data and the incomplete information. To reduce the computational cost of the reliability evaluation, an effective method based on evidence theory was developed. In this method, the mean of the belief measure and the plausibility measure was taken as the approximation of the system reliability. The discretization methods for uncertain parameters were discussed in the cases of only aleatory uncertainty was involved in the system, and mixed aleatory and epistemic uncertainties were involved, respectively. Algorithms of the evaluations of belief and plausibility functions were proposed for monotonic and non-monotonic systems. Four numerical examples under different conditions were studied. Simulation results showed that, the proposed method was much more effective than Monte Carlo method without sacrificing the accuracy of the resulting reliability. It was a general method suitable for various systems with different types of information.

With the addition of Zn, Co and Fe, the microstructures and properties of SnAgCu solders can be improved obviously, the constitutive response of SnAgCu solder bearing 0.8%Zn, 0.8%Co and 0.8%Fe was studied under uniaxial tension. Anand model was used to represent the inelastic deformation behavior of the lead-free solders. The material parameters of the constitutive relations for SnAgCu(Zn,Co, Fe) solders were determined from separated constitutive relations and experimental results. Combining the model, finite element analysis (FEA) was used to study the thermally induced inelastic deformation and the stress-strain response of the solder joints in wafer-level chip scale packages (WLCSP) mounted on printed circuit boards (PCB). And it is found that the addition of Zn, Co and Fe can enhance the fatigue life of SnAgCu solder joint, the superiority can be found for the addition of Fe among the three elements.

In this paper, we investigate the sandpile group of modified wheels Ŵ 2 n by using a variant of the chip firing game [6] defined on this family of graphs. The family of modified wheels Ŵ 2 n is defined by taking the simple wheel graph W n with n rim vertices and then adding two extra vertices on each of the rim edges. It has 3 n  + 1 number of vertices and size 4 n .

The solutions of a nonlinear Schrödinger equation containing the nonlinear interaction b | ϕ | 2 ϕ and center potential are found using the new method of separation of functions, in which the two wave functions satisfy the soluble and different equations, respectively. Its solution is still a soliton, which possesses both corpuscle and wave feature, its eigenenergy is still determinant and quantized, but its size of eigenenergy is depressed about A 0 ′ 2 b /2 relative to that in linear case. This means that the localized nature of the particles described by the nonlinear Schrödinger equation with a center potential is enhanced due to the nonlinear interaction. This is first time to obtain the soliton solution of the nonlinear Schrödinger equation, which has an important significance and application in the nonlinear science, physics, chemistry, biology and engineering.

High-Speed Supercavitating Vehicles (HSSVs) are characterized by substantially reduced hydrodynamic drag from the fully wetted underwater vehicles. Drag is localized at the nose, where a cavitator generates a cavity that completely envelops the body. In this paper, a vertical plane model incorporated with time-delay effect (memory effect of cavity-vehicle interaction) is developed. Unlike previous models, the authors focus on the immersion angle between supercavity and vehicle used to determine the planing force. Stability analyses are carried out with the delay-dependent pitch-plane model. And a key problem is shown that this time-delay leads to destabilization of limit-cycle motion. A new PID control-algorithm with up-and-down rudder mode is designed, demonstrated by both numerical and experimental studies. The research may be useful for developing the trajectory control system of HSSVs.

The three-dimensional flow induced by a stretching sheet has been reported when both thermaldiffusion and diffusion-thermo effects are present. Jeffery fluid model has been selected as a non-Newtonian fluid model in view of its promising applications in polymer industry. Convective boundary conditions are invoked in the present analysis to make it more interesting for the readers. Suitable variables are utilized to obtained the system of ordinary differential equations. An efficient approach namely HAM has been used to compute the solution. Influences of various physical parameters involved in the momentum, concentration and heat transfer analysis are analyzed. Comparison with the already published work is shown.