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Full-Text Articles in Physical Sciences and Mathematics

Flow Stability Of Hunt Flow Under Low-Intensity Magnetic Field, Dong Shuai, Li Shuang, Xuemin Ye Dec 2019

Flow Stability Of Hunt Flow Under Low-Intensity Magnetic Field, Dong Shuai, Li Shuang, Xuemin Ye

Journal of System Simulation

Abstract: The stability of conducting fluid flow in ducts under magnetic field is vital to materials preparation and the design and operation of thermonuclear fusion cooling system. A model of MHD duct flow which is known as Hunt’s flow is simulated by non-normal mode stability analysis in this study.. The amplification and distribution of optimal primary perturbations are obtained by solving iteratively the direct and adjoint governing equations with respect of the perturbation variables. Four modes of perturbations with different symmetries in the space are considered, and the effect of the low-intensity magnetic field is also taken into …


Understanding The Fundamental Molecular Mechanism Of Osteogenic Differentiation From Mesenchymal Stem Cells, Imelda Trejo, Hristo V. Kojouharov Dec 2019

Understanding The Fundamental Molecular Mechanism Of Osteogenic Differentiation From Mesenchymal Stem Cells, Imelda Trejo, Hristo V. Kojouharov

Applications and Applied Mathematics: An International Journal (AAM)

A mathematical model is presented to study the regulatory effects of growth factors in osteoblastogenesis. The model incorporates the interactions among mesenchymal stem cells, osteoblasts, and growth factors. The resulting system of nonlinear ordinary differential equations is studied analytically and numerically. Mathematical conditions for successful osteogenic differentiation and optimal osteoblasts population are formulated, which can be used in practice to accelerate bone formation. Numerical simulations are also presented to support the theoretical results and to explore different medical interventions to enhance osteoblastogenesis.


Qualitative Analysis Of A Modified Leslie-Gower Predator-Prey Model With Weak Allee Effect Ii, Manoj K. Singh, B. S. Bhadauria Jun 2019

Qualitative Analysis Of A Modified Leslie-Gower Predator-Prey Model With Weak Allee Effect Ii, Manoj K. Singh, B. S. Bhadauria

Applications and Applied Mathematics: An International Journal (AAM)

The article aims to study a modified Leslie-Gower predator-prey model with Allee effect II, affecting the functional response with the assumption that the extent to which the environment provides protection to both predator and prey is the same. The model has been studied analytically as well as numerically, including stability and bifurcation analysis. Compared with the predator-prey model without Allee effect, it is found that the weak Allee effect II can bring rich and complicated dynamics, such as the model undergoes to a series of bifurcations (Homoclinic, Hopf, Saddle-node and Bogdanov-Takens). The existence of Hopf bifurcation has been shown for …


Modified Gaussian Radial Basis Function Method For The Burgers Systems, Hossein Aminikhah, Mostafa Sadeghi Jun 2019

Modified Gaussian Radial Basis Function Method For The Burgers Systems, Hossein Aminikhah, Mostafa Sadeghi

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, the systems of variable-coefficient coupled Burgers equation are solved by a free mesh method. The method is based on the collocation points with the modified Gaussian (MGA) radial basis function (RBF). Dependent parameters and independent parameters and their effect on the stability are shown. The accuracy and efficiency of the method has been checked by two examples. The results of numerical experiments are compared with analytical solutions by calculating errors infinity-norm.


Basic Parameters Of Physical Properties Of The Saline Soils In Roadside Of Highways, A. D. Kayumov Abdubaki Djalilovic, O.Z. Zafarov, N. D. Saidbaxromova Mar 2019

Basic Parameters Of Physical Properties Of The Saline Soils In Roadside Of Highways, A. D. Kayumov Abdubaki Djalilovic, O.Z. Zafarov, N. D. Saidbaxromova

Central Asian Problems of Modern Science and Education

This article provides information about the basic parameters of physical properties of the saline soils in roadside of highways, the key and rational indicators which are determined by the experiments and by calculating respectively in the evaluation of soil physical states, the density of solid particles, the basic parameters of density and moisture of the soil in natural condition


Basic Parameters Of Physical Properties Of The Saline Soils In Roadside Of Highways, A. D. Kayumov Abdubaki Djalilovic, O.Z. Zafarov, N. D. Saidbaxromova Jan 2019

Basic Parameters Of Physical Properties Of The Saline Soils In Roadside Of Highways, A. D. Kayumov Abdubaki Djalilovic, O.Z. Zafarov, N. D. Saidbaxromova

Central Asian Problems of Modern Science and Education

This article provides information about the basic parameters of physical properties of the saline soils in roadside of highways, the key and rational indicators which are determined by the experiments and by calculating respectively in the evaluation of soil physical states, the density of solid particles, the basic parameters of density and moisture of the soil in natural condition


Modeling And Analysis For Underwater High-Speed Supercavitaing Torpedo, He Zhen, Aiping Pang, Jinghua Wang, Fanwei Meng, Guangxiong Wang Jan 2019

Modeling And Analysis For Underwater High-Speed Supercavitaing Torpedo, He Zhen, Aiping Pang, Jinghua Wang, Fanwei Meng, Guangxiong Wang

Journal of System Simulation

Abstract: Supercavitation technology can significantly reduce skin-friction drag of underwater torpedo, and therefore dramatically increase the velocity and attack power of underwater weapons. Because the torpedo is almost entirely enveloped by a supercavity, the hydrodynamic problems of the high-speed supercavitating torpedo (HSST) are complex. The hydrodynamic forces acting on cavitator, fin, and the planing force along the longitude plane of the underwater HSST are analyzed. A benchmark nonlinear dynamics model of supercavitating torpedo is established based on the basic dynamic equations of the longitude plane, and the specific parameters of HSST are calculated. In the longitude plane the motion equation …


Modeling And Simulation Of Difg Unit With Stator Inter-Turn Fault, Boqiang Xu, Liling Sun, Wenjuan Du Jan 2019

Modeling And Simulation Of Difg Unit With Stator Inter-Turn Fault, Boqiang Xu, Liling Sun, Wenjuan Du

Journal of System Simulation

Abstract: The mathematical model of doubly fed induction generator (DFIG) with stator inter-turn fault, which presents itself as standard form state space equation, is deduced and established, for the first time. The corresponding simulation model, i.e. Matlab S-function block is developed and embedded in a Matlab built-in routine simulating DFIG unit comprising wind turbine, converter, related mechanical/electrical control and DFIG. The simulation model of DFIG unit with stator inter-turn fault is established, which is a beneficial extension of Matlab simulation. The stability of DFIG unit under the healthy and faulty conditions is analyzed by using simulation. The results show …


Optimal Siting, Sizing, And Parameter Tuning Of Statcom And Sssc Using Mpso And Remote Coordination Of The Facts For Oscillation Damping Of Power Systems, James Garba Ambafi, Sunusi Sani Adamu Jan 2019

Optimal Siting, Sizing, And Parameter Tuning Of Statcom And Sssc Using Mpso And Remote Coordination Of The Facts For Oscillation Damping Of Power Systems, James Garba Ambafi, Sunusi Sani Adamu

Turkish Journal of Electrical Engineering and Computer Sciences

In electromechanical oscillation damping within power system, power system stabilizers (PSSs) are often deployed. However, a PSS is less effective in damping interarea oscillation and is limited by changes in network configuration due to weak tie-lines and load variations. Consequently, this paper presents a wide-area coordination approach that damps interarea oscillations using FACTS devices and phasor measurement units. We selected a static synchronous compensator (STATCOM) and static series synchronous compensator (SSSC) for realistic power system interarea oscillation damping. The performance of the coordinated FACTS installed in a power system depends on their suitable locations, sizes, tuned parameters, and remote input …


Exponential Stabilization Of A Neutrally Delayed Viscoelastic Timoshenko Beam, Sebti Kerbal, Nasser Eddine Tatar Jan 2019

Exponential Stabilization Of A Neutrally Delayed Viscoelastic Timoshenko Beam, Sebti Kerbal, Nasser Eddine Tatar

Turkish Journal of Mathematics

A Timoshenko type beam subject to a viscoelastic damping in the rotational displacement component is considered. Taking into account a neutral type delay, we prove a fast stability result despite the previously observed destabilizing effect due to delays in such systems. The proof relies on the introduction of nine different functionals with which we modify the energy of the system. These functionals are carefully selected and adapted to cope with both the viscoelasticity and the neutral delay.


Stability Analysis For A Class Of Nabla $(Q,H)$-Fractional Difference Equations, Xiang Liu, Baoguo Jia, Lynn Erbe, Allan Peterson Jan 2019

Stability Analysis For A Class Of Nabla $(Q,H)$-Fractional Difference Equations, Xiang Liu, Baoguo Jia, Lynn Erbe, Allan Peterson

Turkish Journal of Mathematics

This paper investigates stability of the nabla $(q,h)$-fractional difference equations. Asymptotic stability of the special nabla $(q,h)$-fractional difference equations are discussed. Stability theorems for discrete fractional Lyapunov direct method are proved. Furthermore, we give some new lemmas (including important comparison theorems) related to the nabla $(q,h)$-fractional difference operators that allow proving the stability of the nabla $(q,h)$-fractional difference equations, by means of the discrete fractional Lyapunov direct method, using Lyapunov functions. Some examples are given to illustrate these results.


A Circulant Functional Equation For The Additive Function And Its Stability, Vichian Laohakosol, Watcharapon Pimsert, Kanet Ponpetch Jan 2019

A Circulant Functional Equation For The Additive Function And Its Stability, Vichian Laohakosol, Watcharapon Pimsert, Kanet Ponpetch

Turkish Journal of Mathematics

A general solution of a matrix functional equation involving circulant matrices of the additive function is determined, and its stability is established.