Effects of heat and mass transfer in the flow of Burgers fluid over an inclined sheet are discussed. Problems formulation and relevant analysis are given in the presence of thermal radiation and non-uniform heat sourc...Effects of heat and mass transfer in the flow of Burgers fluid over an inclined sheet are discussed. Problems formulation and relevant analysis are given in the presence of thermal radiation and non-uniform heat source/sink. Thermal conductivity is taken temperature dependent. The nonlinear partial differential equations are simplified using boundary layer approximations. The resultant nonlinear ordinary differential equations are solved for the series solutions. The convergence of series solutions is obtained by plotting theη-curves for the velocity, temperature and concentration fields. Results of this work describe the role of different physical parameters involved in the problem. The Deborah numbers corresponding to relaxation time(β1 and β2) and angle of inclination(α) decrease the fluid velocity and concentration field. Concentration field decays as Deborah numbers corresponding to retardation time(β3) and mixed convection parameter(G) increase. Large values of heat generation/absorption parameters A/B, and the temperature distribution across the boundary layer increase. Numerical values of local Nusselt number,-θ′(0), and local Sherwood number,-f′(0), are computed and analyzed. It is found that θ′(0) increases with an increase in β3.展开更多
Surface effects play an important role in the mechanical behavior of nanosized structural elements owing to the increased ratio of surface area to volume. The surface effects on the large deflection of nanowires were ...Surface effects play an important role in the mechanical behavior of nanosized structural elements owing to the increased ratio of surface area to volume. The surface effects on the large deflection of nanowires were considered. Both geometric nonlinearity in finite deformation and surface effects at nanoscale were taken into account to analyze the bending of nanowires subjected to a concentrated force. For simply supported beams and clamped-clamped beams, the influence of surface effects and geometric nonlinearity were discussed in detail. It is found that both surface effects and geometric nonlinearity tend to decrease the deflection of bending nanowires and thus increase the effective elastic modulus of nanowires. Surface effects yield the size dependent behavior of nanowires.展开更多
We introduce a new type of path-dependent quasi-linear parabolic PDEs in which the continuous paths on an interval [0, t] become the basic variables in the place of classical variables （t, x） ∈[0, T]× R^d. Thi...We introduce a new type of path-dependent quasi-linear parabolic PDEs in which the continuous paths on an interval [0, t] become the basic variables in the place of classical variables （t, x） ∈[0, T]× R^d. This new type of PDEs are formulated through a classical BSDE in which the terminal values and the generators are allowed to be general function of Brownian motion paths. In this way, we establish the nonlinear Feynman- Kac formula for a general non-Markoviau BSDE. Some main properties of solutions of this new PDEs are also obtained.展开更多
In this study, we have constructed a new numerical approach for solving the time-dependent linear and nonlinear Fokker-Planck equations. In fact, we have discretized the time variable with Crank-Nicolson method and fo...In this study, we have constructed a new numerical approach for solving the time-dependent linear and nonlinear Fokker-Planck equations. In fact, we have discretized the time variable with Crank-Nicolson method and for the space variable, a numerical method based on Generalized Lagrange Jacobi Gauss-Lobatto(GLJGL) collocation method is applied. It leads to in solving the equation in a series of time steps and at each time step, the problem is reduced to a problem consisting of a system of algebraic equations that greatly simplifies the problem. One can observe that the proposed method is simple and accurate. Indeed, one of its merits is that it is derivative-free and by proposing a formula for derivative matrices, the difficulty aroused in calculation is overcome, along with that it does not need to calculate the General Lagrange basis and matrices; they have Kronecker property. Linear and nonlinear Fokker-Planck equations are given as examples and the results amply demonstrate that the presented method is very valid, effective,reliable and does not require any restrictive assumptions for nonlinear terms.展开更多
This paper focuses on the study of a class of asymptotically almost periodic Nicholson＇s blowflies models with a nonlinear density-dependent mortality term. By virtue of differ-ential inequality techniques, a set of ...This paper focuses on the study of a class of asymptotically almost periodic Nicholson＇s blowflies models with a nonlinear density-dependent mortality term. By virtue of differ-ential inequality techniques, a set of easily verifiable sufficient conditions are established to show that every solution of the considered model is asymptotically almost periodic, and it also converges to a same almost periodic function as t →＋∞ , which improves and supplements some previously known researches. Moreover, a numerical example is given to test the feasibility and effectiveness of the obtained results.展开更多
The authors prove the global null controllability for the 1-dimensional nonlinear slow diffusion equation by using both a boundary and an internal control. They assume that the internal control is only time dependent....The authors prove the global null controllability for the 1-dimensional nonlinear slow diffusion equation by using both a boundary and an internal control. They assume that the internal control is only time dependent. The proof relies on the return method in combination with some local controllability results for nondegenerate equations and rescaling techniques.展开更多
文摘Effects of heat and mass transfer in the flow of Burgers fluid over an inclined sheet are discussed. Problems formulation and relevant analysis are given in the presence of thermal radiation and non-uniform heat source/sink. Thermal conductivity is taken temperature dependent. The nonlinear partial differential equations are simplified using boundary layer approximations. The resultant nonlinear ordinary differential equations are solved for the series solutions. The convergence of series solutions is obtained by plotting theη-curves for the velocity, temperature and concentration fields. Results of this work describe the role of different physical parameters involved in the problem. The Deborah numbers corresponding to relaxation time(β1 and β2) and angle of inclination(α) decrease the fluid velocity and concentration field. Concentration field decays as Deborah numbers corresponding to retardation time(β3) and mixed convection parameter(G) increase. Large values of heat generation/absorption parameters A/B, and the temperature distribution across the boundary layer increase. Numerical values of local Nusselt number,-θ′(0), and local Sherwood number,-f′(0), are computed and analyzed. It is found that θ′(0) increases with an increase in β3.
基金Project(11072186)supported by the National Natural Science Foundation of China
文摘Surface effects play an important role in the mechanical behavior of nanosized structural elements owing to the increased ratio of surface area to volume. The surface effects on the large deflection of nanowires were considered. Both geometric nonlinearity in finite deformation and surface effects at nanoscale were taken into account to analyze the bending of nanowires subjected to a concentrated force. For simply supported beams and clamped-clamped beams, the influence of surface effects and geometric nonlinearity were discussed in detail. It is found that both surface effects and geometric nonlinearity tend to decrease the deflection of bending nanowires and thus increase the effective elastic modulus of nanowires. Surface effects yield the size dependent behavior of nanowires.
基金supported by National Natural Science Foundation of China(Grant No.10921101)the Programme of Introducing Talents of Discipline to Universities of China(Grant No.B12023)the Fundamental Research Funds of Shandong University
文摘We introduce a new type of path-dependent quasi-linear parabolic PDEs in which the continuous paths on an interval [0, t] become the basic variables in the place of classical variables （t, x） ∈[0, T]× R^d. This new type of PDEs are formulated through a classical BSDE in which the terminal values and the generators are allowed to be general function of Brownian motion paths. In this way, we establish the nonlinear Feynman- Kac formula for a general non-Markoviau BSDE. Some main properties of solutions of this new PDEs are also obtained.
文摘In this study, we have constructed a new numerical approach for solving the time-dependent linear and nonlinear Fokker-Planck equations. In fact, we have discretized the time variable with Crank-Nicolson method and for the space variable, a numerical method based on Generalized Lagrange Jacobi Gauss-Lobatto(GLJGL) collocation method is applied. It leads to in solving the equation in a series of time steps and at each time step, the problem is reduced to a problem consisting of a system of algebraic equations that greatly simplifies the problem. One can observe that the proposed method is simple and accurate. Indeed, one of its merits is that it is derivative-free and by proposing a formula for derivative matrices, the difficulty aroused in calculation is overcome, along with that it does not need to calculate the General Lagrange basis and matrices; they have Kronecker property. Linear and nonlinear Fokker-Planck equations are given as examples and the results amply demonstrate that the presented method is very valid, effective,reliable and does not require any restrictive assumptions for nonlinear terms.
文摘This paper focuses on the study of a class of asymptotically almost periodic Nicholson＇s blowflies models with a nonlinear density-dependent mortality term. By virtue of differ-ential inequality techniques, a set of easily verifiable sufficient conditions are established to show that every solution of the considered model is asymptotically almost periodic, and it also converges to a same almost periodic function as t →＋∞ , which improves and supplements some previously known researches. Moreover, a numerical example is given to test the feasibility and effectiveness of the obtained results.
基金Project supported by the ITN FIRST of the Seventh Framework Programme of the European Community (No. 238702)the ERC advanced grant 266907 (CPDENL) of the 7th Research Framework Programme (FP7)+1 种基金DGISPI of Spain (Project MTM2011-26119)the Research Group MOMAT(No. 910480) supported by UCM
文摘The authors prove the global null controllability for the 1-dimensional nonlinear slow diffusion equation by using both a boundary and an internal control. They assume that the internal control is only time dependent. The proof relies on the return method in combination with some local controllability results for nondegenerate equations and rescaling techniques.
