Top PDF ON A NONLINEAR THIRD-ORDER EVOLUTION EQUATION - PRESENT DEVELOPMENTS

ON A NONLINEAR THIRD-ORDER EVOLUTION EQUATION - PRESENT DEVELOPMENTS

ON A NONLINEAR THIRD-ORDER EVOLUTION EQUATION - PRESENT DEVELOPMENTS

Although the origin of nonlinear partial differential equations (nPDEs) is very old, they have undergone remarkable new developments during the last half of the twenty century. One of the main impulses for developing nPDEs has been the study of nonlinear wave propagation problems. These problems arise in different areas of applied mathematics, physics, engineering, including fluid dynamics, nonlinear optics, solid mechanics, plasma physics, field theories, and condensed matter theories to mention some practical examples.

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Amplitude Amplification Factor of Bi-chromatic Waves Propagation in Hydrodynamic Laboratories

Amplitude Amplification Factor of Bi-chromatic Waves Propagation in Hydrodynamic Laboratories

wave is a wave whose height exceeds the significant wave height of measured wave train by factor more than 2.2 [1] and [2]. Occurrences (where and when) of this wave are not easy to predict, but its impact can cause damage to oceanic objects, i.e. ships and marine structures, that are around this wave (see Earle [3], Mori et al [4], Divinsky and Levin [5], Truslen and Dysthe [6], Smith [7], Toffoli and Bitner [8] and Waseda et al. [9]). Therefore, information about the presence of freak waves is important for offshore activities. The presence has been often reported in media. Nikolkina and Didenkulova [10] collected and analysed freak waves reported in media in 2006-2010. To understand the occurrence, propagation and generation of the extreme wave, various studies have been conducted by many researchers. Waseda et al. [11] conducted deep water observation of freak waves in the North West Pacific Ocean. Hu et al. [12] studied numerically rogue wave based on nonlinear Schrodinger breather solutions under finite water depth. Islas and Schober [13] investigated the effects of dissipation on the development of rogue waves and down shifting by adding nonlinear and linear damping terms to the one-dimensional Dysthe equation. Xu et al. [14] proposed (2 + 1)- dimensional Kadomtsev–Petviashvili equation, homoclinic (heteroclinic) breather limit method (HBLM), for seeking rogue wave solu- tion to nonlinear evolution equation (NEE). The wave ampli- fication in the framework of forced non linear Schrodinger equation is observed by Slunyaev et al. [15]. Cahyono et al. [16] discussed multi-parameters perturbation method for dispersive and nonlinear partial differential equations. Ramli [17] investigated nonlinear evolution of wave group with three frequencies using third order approximation of Ko- rteweg de Vries equation and Maximal Temporal Amplitude. Wabnitz et al. [18] observed extreme wave events which are generated in the modulationally stable normal dispersion regime. Peric et al. [19] regarded a prototype for spatio- temporally localizing rogue waves on the ocean caused by nonlinear focusing and analyzed by direct numerical simulations based on two phase Navier–Stokes equations. Blackledge [20] found the explicit freak waves can not be obtained by pure intuition or by elementary calculations because of their complications. Onorato et al. [21] discussed rogue waves occurring in different physical contexts and related anomalous statistics of the wave amplitude, which deviates from the Gaussian behavior that were expected for random waves. Extreme wave generation using self- correcting method was studied by Fernandez et al. [22]. Xi- eng et al. [23] simulated the extreme wave generation are carried out by using the volume of fluid (VOF) method.
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Steep unidirectional wave groups  –  fully nonlinear simulations vs. experiments

Steep unidirectional wave groups – fully nonlinear simulations vs. experiments

This combined numerical and experimental study of non- linear wave trains also clarifies the limitations of possible agreement between fully nonlinear solution and experiment. We note that while the periodicity in the time domain is pos- sible for propagating and evolving unidirectional waves, they are, strictly speaking, aperiodic in space. This point adds an additional aspect to essential differences that exist between the spatial and temporal formulations of the wave evolu- tion problem, as discussed above. We therefore believe that all nonlinear solutions based on spatially periodic boundary conditions, as in the method adopted here, as well as in a variety of alternative methods that employ spatial discrete Fourier decomposition, contain intrinsic inaccuracy. These numerical solutions thus can only provide approximate re- sults and require careful experiments to verify their valid- ity. The present study shows that the fully nonlinear solution, although flawed, yields better agreement with experiments than the application of the spatial version of the modified nonlinear Schrödinger (Dysthe) equation limited to the third order that does not require spatial periodicity (Shemer and Alperovich (2013).
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Optimal Control Using State-dependent Riccati Equation (SDRE) for a Hydraulic Actuator

Optimal Control Using State-dependent Riccati Equation (SDRE) for a Hydraulic Actuator

In the past, much of the work in the control of hydraulic systems has used linear model [3] or local linearization of the nonlinear dynamics about the nominal operating point [4]. Suitable adaptive approaches are employed when there is no knowledge of the parameter values [5], [6]. In order to take system uncertainties into account, robust approaches can be adopted [7], [8]. In [9], a sliding mode control

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A discrete homotopy perturbation method for non-linear Schrodinger equation

A discrete homotopy perturbation method for non-linear Schrodinger equation

The Schrödinger equation being a partial differential equation describes the quantum state of a physical system and the changes in that system with respect to time. It was first time formulated by Schrödinger in 1925(Schrödinger, 1926) . In the sense of classical mechanics, the governing equation predicts the behavior of a system mathematically at any time after the initial state of the system is set and this corresponds to the Newton’s law  F  ma  . In the language of quantum mechanics, the Schrödinger equation is analogous to Newton’s law for quantum mechanical system (which usually involves molecules, atoms, sub-atomic particles, whether moving freely, bounded or localized). It is not as simple algebraic operation but in general form it is a linear partial differential equation that describes the evaluation of time of the wave function system (Griffiths, 2004).
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Approximations of the nonlinear Painlevand#233; transcendents

Approximations of the nonlinear Painlevand#233; transcendents

(1910) that all equations of this type whose solutions do not have movable critical points (but are allowed to have fixed singular points and movable pole) can be reduced to 50 classes of equations. Moreover, 44 classes out of them are in- tegrable by quadrature or admit reduction of order. The remaining 6 equations are irreducible; these are known as the Painlev´e equations or Painlev´e transcendent, and their solutions are known as the Painlev´e transcendental functions. It is significant that the Painlev´e equations often arise in mathematical physics. Some connections are given as follows:
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Organizational evolution of China’s third-front enterprises: cases study on Aosheng Group

Organizational evolution of China’s third-front enterprises: cases study on Aosheng Group

From the historical evolution of the Third-front construction policy we can see that the evolution of Chinese Communist Party’s regional development theory influences the third construction policy and historical process (Zhong, 2011) (仲海涛, 2011). Zhong Haitao (2011) points out that the social, historical, political and economic conditions at home and abroad varies at different periods. So do the ideas on China's regional development. The Third-front construction largely represents Chinese Communist Party’s ideas on regional development.
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Dynamic Analysis of Imperfect FGM Circular Cylindrical Shells Reinforced by FGM Stiffener System Using Third Order Shear Deformation Theory in Term of Displacement Components

Dynamic Analysis of Imperfect FGM Circular Cylindrical Shells Reinforced by FGM Stiffener System Using Third Order Shear Deformation Theory in Term of Displacement Components

A novelty of the present study is to present an analytical method for investigate dynamic re- sponse of imperfect FGM circular cylindrical shells reinforced by FGM stiffener system and filled inside by an elastic foundations, in thermal environments. Theoretical formulations in terms of dis- placement components according to Reddy’s third-order shear deformation shell theory (2004) and the smeared stiffeners technique are derived. The thermal elements of shells and stiffeners are taken into account in two cases which are uniform temperature rise law and nonlinear temperature change. The closed-form expressions for determining the natural frequency, nonlinear frequency- amplitude curve and nonlinear dynamic response are obtained by using Galerkin method and fourth-order Runge-Kutta method. The effects of stiffener, temperature, foundation, material and dimensional parameters, pre-existent axial compressive and on the stability of stiffened FGM shells are considered.
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On the Stability and Ultimate Boundedness of Solutions for Certain Third Order Differential Equations

On the Stability and Ultimate Boundedness of Solutions for Certain Third Order Differential Equations

4. Andres, J., 1986. Boundedness results for solutions of the equation &&& x + ax && + g(x)x & + h(x) = p(t) without the hypothesis h(x)sgnx ≥ 0 for x > R . Atti. Accad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Natur., 80: 533-539. DOI: MR0976947(89m:34043). 5. Bereketoglu, H. and Györi, I.; 1997. On the

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Multiple periodic solutions for a fourth-order discrete Hamiltonian system

Multiple periodic solutions for a fourth-order discrete Hamiltonian system

The theory of nonlinear difference equations (including discrete Hamiltonian systems) has been widely used to study discrete models in many fields such as computer science, economics, neural networks, ecology and so on. Many scholars studied the qualitative properties of difference equations such as stability, oscillation and boundary value problems (see e.g. [1, 2, 3] and references cited therein). But results on periodic solutions of difference equations are relatively rare and the results usually obtained by analytic techniques or various fixed point theorems (see e.g. [4]). We may think of (1.1) as being a discrete analogue of the following fourth-order Hamiltonian system
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Nonlinear difference equations for a modified Laguerre weight: Laguerre-Freud equations and asymptotics

Nonlinear difference equations for a modified Laguerre weight: Laguerre-Freud equations and asymptotics

In this paper we derive second and third order nonlinear difference equations for one of the recurrence coefficients in the three term recurrence relation of polyno- mials orthogonal with respect to a modified Laguerre weight. We show how these equations can be obtained from the B¨ acklund transformations of the third Painlev´ e equation. We also show how to use nonlinear difference equations to derive a few terms in the formal asymptotic expansions in n of the recurrence coefficients.

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Simple but accurate periodic solutions for the nonlinear pendulum equation

Simple but accurate periodic solutions for the nonlinear pendulum equation

In this note, periodic analytical approximations for the exact solution of the pendulum equation of motion are proposed. As a first approximate solution, I have modi- fied the harmonic approximation proposed in Ref. [17], which resulted in an accurate approximation for ampli- tudes up to π/3 rad. However, due to the unavoidable loss of harmonicity with the increase of amplitude, the harmonic approximation soon becomes poor. In fact, for amplitudes above π/2 rad, which are of interest for some experiments [4, 8, 26–28], the deviations are significant, as shown in Fig. 3. Then, I have found it natural to take the periodicity of the exact solution into account to derive an analytical Fourier series expansion, giving continuity to a numerical treatment I have developed (with co-authors) in a very recent work [24]. This task re- vealed many complexities due to the inverse sine function present in the exact solution, our Eq. (16), so I decided to expand only the (periodic) Jacobi elliptic function sn(u; k), rather than the whole function θ(t). The trunca- tion of this series to only a few terms has revealed itself as a good approximation technique, yielding relative er- rors smaller than 0.4% even for amplitudes as large as
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Braz. J. Chem. Eng.  vol.29 número4

Braz. J. Chem. Eng. vol.29 número4

Abstract - The main objective of this study was to evaluate the effect of the drying process on the vitamin C levels and physical properties of dedo-de-moça pepper. The drying kinetics and the structural properties were determined as a function of moisture content. Convective drying was compared with freeze-drying in terms of product quality, structural properties, retention of vitamin C and rehydration characteristics. Empirical and semi-empirical equations were used to describe the drying and rehydration kinetics. Nonlinear analysis applied to results of convective drying, based on curvature measures and bias measures, showed that the only equation that gives good inference results based on least squares estimators is the Overhults equation. The characterization of the rehydration process was done by determining the indexes that take into account the water absorption capacity and solutes losses. The material dried by lyophilization show greater potential to rehydrate.
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PRECISION AGRICULTURE IN AUSTRALIA: PRESENT STATUS AND RECENT DEVELOPMENTS ROBERT BRAMLEY

PRECISION AGRICULTURE IN AUSTRALIA: PRESENT STATUS AND RECENT DEVELOPMENTS ROBERT BRAMLEY

(1997) yield monitor. However, coupled to a booming world sugar market, much of the present interest has been inspired by the recent availability to Australian cane farmers of grants which support adoption of farming methods which are perceived to reduce the impact of agriculture on the Great Barrier Reef; PA, and VRA in particular, is such a technology (BRAMLEY et al., 2008). There are two significant problems with this. First, the inaccuracy of the fertilizer delivery mechanisms used by Australian sugarcane growers (Dr Bernard Schroeder and John Panitz, BSES Ltd - pers. comm) raise serious questions about the merits of retro-fitting these with VRA controllers. Second, and arguably of more immediate importance, the present lack of a robust, commercially available sugarcane yield monitoring system in Australia (JENSEN et al., 2010) casts doubt on the basis for delineating management zones in sugar fields and thus, VRA. A major research effort which addresses these issues and the means by which sugar growers might adopt PA is presently underway. Nevertheless, auto-steer technology is being rapidly adopted in the Australian sugar industry and, as has been the case with grains (see above); this is expected to increase interest and adoption, which is otherwise lagging behind other major cropping industries.
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Impact of model developments on present and future simulations of permafrost in a global land-surface model

Impact of model developments on present and future simulations of permafrost in a global land-surface model

3.2 Permafrost distribution in historical simulation The simulated permafrost in JULES is shown in Fig. 7, along with observations from the Circum-Arctic map of permafrost and ground-ice conditions (Brown et al., 1998) (Sect. 2.4.6). The observed map shows areas with continuous, discontin- uous and sporadic permafrost and isolated patches. There is no equivalent of discontinuous permafrost in JULES be- cause each grid box has only a single soil column, so in or- der to compare the two maps we assume that a deeper active layer in JULES may correspond to discontinuous or sporadic permafrost. With this assumption, all the simulations match the observations fairly well in most areas. We can see that introducing the model developments brings in much more spatial variability in ALT, which generally matches with the patterns of continuous/discontinuous permafrost. The corre- lation between the ALT in JULES and the percentage cover of permafrost from (Brown et al., 1998) (100 % for continu- ous, 90 % for discontinuous, 50 % for sporadic and 10 % for isolated patches) is high, ranging between −0.37 and −0.51. However, there are still places where continuous per- mafrost is observed but JULES does not simulate permafrost. Figure 8 shows that in most of these areas, JULES simulates far too much snow, which will mean too much insulation in winter leading to soils that are too warm. This is particularly noticeable in north-east Canada and two areas in north-west Russia. In north-east Canada, however, it has been shown that the GlobSnow data set underestimates the SWE (Langlois et al., 2014), so the over-estimation in JULES may not be as large as Fig. 8 suggests. However, the permafrost in this re- gion is unstable to thawing (Thibault and Payette, 2009), so a small bias in the model could make the difference between simulating permafrost or not. For most of the remaining land surface, JULES slightly underestimates the SWE. Hancock et al. (2014) showed that JULES generally underestimates SWE when driven by reanalysis data sets.
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A Model Third Order Phase Transition in Fe-Pnictide Superconductors

A Model Third Order Phase Transition in Fe-Pnictide Superconductors

By identifying the orders of phase transition through the analytic continuation of the functional of the free energy of the Ehrenfest theory, we have developed a theory for studying the dependence of the local magnetic moment, M on the Fe – As layer sep- aration in the third order phase transition regime. We derived the Euler – Lagrange equation for studying the dynamics of the local magnetic moment, and tested our model with available experimental data.

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Comput. Appl. Math.  vol.26 número1

Comput. Appl. Math. vol.26 número1

x (4) + ϕ( x) .. ... x + f (x, x, . x) + g(x, .. x) + h(x) = p(t, x, . x, . x, .. ... x ), (1.1) where ϕ, f, g, h and p are continuous functions which depend only on the argu- ments displayed. The dots indicate differentiation with respect to the independent variable t and all solutions considered are assumed real. The derivatives,

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On Quadratic Integral Equations of Urysohn Type in Fréchet Spaces

On Quadratic Integral Equations of Urysohn Type in Fréchet Spaces

Integral equations arise naturally from many applications in describing numer- ous real world problems, see, for instance, books by Agarwal et al. [1], Agarwal and O’Regan [2], Corduneanu [8], Deimling [13], O’Regan and Meehan [18] and the references therein. On the other hand, also quadratic integral equations have many useful applications in describing numerous events and problems of the real world. For example, quadratic integral equations are often applicable in the theory of radiative transfer, kinetic theory of gases, in the theory of neutron transport and in the traffic theory. Especially, the so-called quadratic integral equation of Chandrasekher type can been countered very often in many applications; see for instance the book by Chandrasekher [7] and the research papers by Banas et al. [3, 4], Benchohra and Darwish [6], Darwish [9, 10, 11, 12], Hu et al. [15], Kelly [16], Leggett [17], Stuart [19] and the references therein. In [3] Banas et al. established the existence of monotonic solutions of a Volterra counter part of equation (1) by means of a technique associated with measure of noncompactness.
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Searching for complexity in the human pupillary light reflex

Searching for complexity in the human pupillary light reflex

As is widely known, since the concept of derivative was first developed, the ordinary differential equations have been used to model natural phenomena and they have provided a good approximation to determine its behavior. However, they involve functions and their derivatives that all evolve at the same time t. This is a feature that does not take into account the non-instantaneous nature of many phenomena. Additionally, phenomena with a delayed effect have been found. These phenomena are best modeled by a more general type of equations, the so-called delay differential equations (DDEs), making them one of the mathematical “tools” widely used in many applications ([1,2]). Such applications arise in a wide variety of fields as biophysics [3], biology [4], chemistry [5], climate [6] or even medicine [7], whenever it is essential to portray the non-instantaneous nature of the processes [8]. Within this framework, mathematical models for neural reflex mechanisms often take the form of a first-order DDE, that is
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Braz. J. Phys.  vol.31 número2

Braz. J. Phys. vol.31 número2

tion of non linear terms into the evolution equation.. The region of.[r]

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