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Abstract: In this paper, we study the combined effect of internal-heating and time-periodic gravity modulation on thermal instability in a viscous fluid layer, heated from below. The time-periodic gravity modulation, considered in this problem can be realized by vertically oscillating the fluid layer. A weak non-linear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number has been obtained in terms of the amplitude of convection which is governed by the non-autonomous Ginzburg–Landau equation derived for the stationary mode of convection. Effects of various parameters such as internal Rayleigh number, Prandtl number, and amplitude and frequency of gravity modulation have been analysed on heat transport. It is found that the response of the convective system to the internal Rayleigh number is destabilizing. Further, it is found that the heat transport can be controlled by suitably adjusting the external parameters of the system. [Copyright &y& Elsevier]

The dietary energy for broiler chicken is provided through the inclusion of cereal grains and veg-etable oil in the ration. The cost of corn is increasing ex-ponentially, whereas sugar syrup (SS) is available with reasonable cost. Sugar syrup can be used as a substi-tute for starch/grains and vegetable oil. No research has been reported on the effect of SS on broiler meat qual-ity. In this study, Hubbard commercial broiler chicks were fed a control basal diet (corn-soy basal diet on an ad libitum basis) alone or with graded levels of SS. A completely randomized design with 3 replications (n = 3, treatments - 4 with 4 subsamples per treatment) were used to investigate the effect of replacing part of the corn and oil in broiler chicken rations with graded levels of SS (5, 10, and 15%) on breast and thigh meat quality (proximate analysis, cooking loss, instrumental color, and texture and sensory properties). Rations con-taining up to 15% SS had a slight effect on proximate composition of raw and cooked broiler breast and thigh meats. Cooking loss of thigh meat decreased signifi-cantly with increasing SS but increased significantly for breast meats. No significant differences were detected (P > 0.05) among breast or thigh meats fed rations with a different level of SS on all sensory properties, ex-cept that cooked thigh meat had a slightly harder tex-ture. Overall, results suggest that feeding broilers with SS rations (up to 15%) produced high-quality breast and thigh meats with minimal differences. [ABSTRACT FROM AUTHOR]

Abstract: An adaptive Legendre–Gauss–Radau collocation method is presented for solving time-varying delay systems. By dividing the domain of the problem into a uniform mesh, the delay system is replaced with a sequence of initial value problems. The method developed in this paper adjusts both the mesh spacing and the degree of the polynomial on each mesh interval in order a specified error tolerance is satisfied. We investigate some error estimates on the whole domain of interest. Some numerical examples are given and comparisons with other methods are made to demonstrate the efficiency and accuracy of the proposed method. [Copyright &y& Elsevier]

Abstract: In this paper, the non-standard finite difference method (for short NSFD) is implemented to study the dynamic behaviors in the fractional-order Rössler chaotic and hyperchaotic systems. The Grünwald–Letnikov method is used to approximate the fractional derivatives. We found that the lowest value to have chaos in this system is 2.1 and hyperchaos exists in the fractional-order Rössler system of order as low as 3.8. Numerical results show that the NSFD approach is easy to implement and accurate when applied to differential equations of fractional order. [Copyright &y& Elsevier]

Abstract: Features of nonlinear dynamics of thermal convection in an electrically conducting fluid layer heated from below and cooled from above subjected to a constant magnetic field are studied theoretically. The Galerkin truncated approximation is employed to derive a low dimensional Lorenz-like model. Numerical analysis was performed to examine the influence of magnetic field on the phase space trajectory of various chaotic regimes. The result indicates that it is possible to suppress or enhance the chaotic convection. [Copyright &y& Elsevier]

Abstract: This study investigated the instability of Bénard–Marangoni convection in a horizontal layer of ferrofluid under the influence of a linear feedback control and cubic temperature profile. A linear stability analysis was performed. A single-term Galerkin technique was used to obtain the critical Marangoni number and critical Rayleigh number. The possibility of delaying the onset of convection by the application of linear feedback control is demonstrated. [Copyright &y& Elsevier]

Abstract: Using the theory of dynamical systems, this study investigated the effects of a uniform internal heat generation on chaotic behaviour in thermal convection in a fluid-saturated porous layer subject to gravity and heated from below for low Prandtl number. A low-dimensional, Lorenz-like model was obtained using Galerkin truncated approximation. The fourth-order Runge–Kutta method was employed to solve the nonlinear system. We found that there is an inverse proportional relation between the level of internal heat G and the scaled Rayleigh number R, and consequently the porous media gravity-related Rayleigh number Ra. [Copyright &y& Elsevier]

Abstract: In this paper, the effects of thermocapillarity and a magnetic field on the flow and heat transfer in a liquid film over an unsteady elastic stretching surface is analyzed. Similarity transformations are used to transform the governing equations to a set of coupled ordinary differential equations. The differential equations are solved analytically by the homotopy analysis method (HAM). The effects of various parameters in this study are discussed and presented graphically. [Copyright &y& Elsevier]

Yogurt is considered a healthy food and incorporating dietary fiber will make it even healthier. Date fiber (DF), a by-product of date syrup production, is a good source of dietary fiber. The effect of fortification with DF on fresh yogurt quality was investigated. Acidity, pH, color [L* (lightness), a* (redness), and b* (yellowness) values], texture profile, sensory properties, and consumer acceptance were studied. Control yogurt (without fiber), yogurt fortified with 1.5, 3.0, and 4.5% DF, and yogurt with 1.5% wheat bran (WB) were prepared. Fortification with DF did not cause significant changes in yogurt acidity, although pH was increased. Yogurts fortified with DF had firmer texture (higher hardness values) and darker color (lower L* and higher a*) compared with control or WB yogurts. Consumer test results indicated that the appearance, color, and flavor ratings were significantly affected by fiber fortification. Yogurt fortified with up to 3% DF had similar sourness, sweetness, firmness, smoothness, and overall acceptance ratings as the control yogurt. Sensory ratings and acceptability of yogurt decreased significantly when increasing DF to 4.5% or using 1.5% WB. Flavoring yogurt fortified with 4.5% DF with vanilla did not improve flavor or overall acceptance ratings. Thus, fortifying yogurt with 3% DF produced acceptable yogurt with beneficial health effects. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a feedback control strategy on the onset of oscillatory convection in an infinite horizontal layer of fluid with temperature-dependent viscosity is investigated theoretically using linear stability analysis. It is shown that small viscosity variations stabilizes the fluid layer. Large controller gains, large viscosity variations, and high surface tension, however, promote the onset of overstability leading to oscillatory motions. [Copyright &y& Elsevier]

Camel milk (CM) set yogurts were formulated with gelatin, alginate (ALG), and calcium (Ca). Titratable acidity, pH, sensory properties, and acceptability of CM yogurts were studied. Twelve treatments were prepared; 3 using gelatin at 0.5, 0.75, and 1% levels and 9 with combinations of ALG and Ca at different levels. Titratable acidity and pH of fresh yogurt were not affected by the addition of gelatin or the ALG and Ca combinations. Trained sensory panel results showed that CM yogurt containing 1% gelatin or 0.75% ALG + 0.075% Ca had the highest intensities for firmness and body. Consumer results indicated that the hedonic ratings of the sensory attributes and acceptability of CM yogurt containing 0.75% ALG + 0.075% Ca were similar to that of cow's milk yogurt. The CM yogurts containing ALG + Ca and flavored with 4 different fruit concentrates (15%) had similar hedonic ratings and acceptability. Addition of 0.75% ALG + 0.075% Ca could be used to produce acceptable plain or flavored CM yogurt. [ABSTRACT FROM AUTHOR]

Abstract: The onset of steady thermocapillary (surface-tension-driven Marangoni) instability in a horizontal fluid layer in the presence of a uniform heat generation is considered theoretically using stability theory. The fluid layer, heated from below, is bounded above by a deformable free upper surface and below by a rigid plane boundary. The stability of the fluid layer is investigated and subjected to a feedback control on the temperatures of the boundaries. An exact solution for marginal stability owing to an exchange of stabilities has been obtained. Long wavelength instability may coexist with a finite wavelength instability for certain sets of parameter values, often referred to as frontier points. [Copyright &y& Elsevier]

Abstract: In this paper, a new reliable algorithm based on an adaptation of the standard homotopy-perturbation method (HPM) is applied to the Chen system which is a three-dimensional system of ODEs with quadratic nonlinearities. The HPM is treated as an algorithm in a sequence of intervals for finding accurate approximate solutions to the Chen system. We shall call this technique as the multistage HPM (for short MHPM). In particular we look at the accuracy of the HPM as the Chen system changes from a nonchaotic system to a chaotic one. Numerical comparisons between the MHPM and the classical fourth-order Runge–Kutta (RK4) numerical solutions reveal that the new technique is a promising tool for the nonlinear chaotic and nonchaotic systems of ODEs. [Copyright &y& Elsevier]

Abstract: In this paper, approximate and/or exact analytical solutions of the generalized Emden–Fowler type equations in the second-order ordinary differential equations (ODEs) are obtained by homotopy-perturbation method (HPM). The homotopy-perturbation method (HPM) is a coupling of the perturbation method and the homotopy method. The main feature of the HPM is that it deforms a difficult problem into a set of problems which are easier to solve. In this work, HPM yields solutions in convergent series forms with easily computable terms, and in some cases, only one iteration leads to the high accuracy of the solutions. Comparisons with the exact solutions and the solutions obtained by the Adomian decomposition method (ADM) show the efficiency of HPM in solving equations with singularity. [Copyright &y& Elsevier]

Abstract: In this paper, the fractional modified Korteweg–de Vries equation (fmKdV) is introduced by replacing the first-order time and space derivatives by fractional derivatives of order and with . The homotopy-perturbation method (HPM) is applied to derive approximate analytical solutions to fmKdV. [Copyright &y& Elsevier]

Abstract: The Marangoni instability in a temperature-dependent-viscosity fluid layer with deformable free surface under the influence of a linear feedback control strategy is investigated. The exact analytical solution for the stationary modes is developed and the effects of the interaction between variable viscosity, controller gains, free surface deformation, gravity waves and heat transfer mechanism on the onset of Marangoni convection are determined. The destabilizing effect of exponential viscosity variation can be effectively suppressed through small controlled perturbations in the thermal boundary data. [Copyright &y& Elsevier]

Abstract: The effect of feedback control on the onset of steady and oscillatory surface-tension-driven (Marangoni) convection in a rotating horizontal fluid layer with a flat free upper surface and heated from below is considered theoretically using linear stability theory. The role of the controller gain parameter on the Ta–Pr parameter space, dividing stability domains into which either steady or oscillatory convection is preferred, is determined. [Copyright &y& Elsevier]

Abstract: The onset of stationary Marangoni instabilities in a horizontal fluid layer with free surface deformation and heated from below with a uniform heat flux is considered theoretically using linear stability theory. The explicit solution is obtained and the influences of temperature-dependent viscosity, surface deformability, gravity waves and heat transfer mechanism at the free surface on the stability thresholds are investigated. Small stabilizing effect is observed in fluids with a small viscosity variation while large viscosity variation strongly destabilizes the fluid layer. The stability thresholds are critically dependent on viscosity variation, surface deformation and heat transfer mechanism. [Copyright &y& Elsevier]

Abstract: In this Letter, we apply the homotopy-perturbation method (HPM) to obtain approximate analytical solutions of the time-dependent Emden–Fowler type equations. We also present a reliable new algorithm based on HPM to overcome the difficulty of the singular point at . The analysis is accompanied by some linear and nonlinear time-dependent singular initial value problems. The results prove that HPM is very effective and simple. [Copyright &y& Elsevier]

Abstract: In this Letter, the homotopy-perturbation method (HPM) is employed to derive approximate series solutions of nonlinear population dynamics models. The nonlinear models considered are the multispecies Lotka–Volterra equations. The accuracy of this method is examined by comparison with the available exact and the fourth-order Runge–Kutta method (RK4). [Copyright &y& Elsevier]

Abstract: In this Letter, solutions of a class of singular initial value problems (IVPs) in the second-order ordinary differential equations (ODEs) by homotopy-perturbation method (HPM) are presented. HPM yields solutions in convergent series forms with easily computable terms, and in some cases, yields exact solutions in one iteration. Comparisons with the exact solutions and the solutions obtained by the decomposition method show the potential of HPM in solving singular problems. [Copyright &y& Elsevier]