Since the doubly clamped beam-type N/MEMS subjected to the van der Waals attraction is transformed into a mathematical model through Galerkin method, which is a nonlinear differential equation, the ...spreading residue harmonic balance method is introduced to solve the approximate solution of the nonlinear problem in this paper. The spreading residue harmonic balance method is developed on the basis of the residue harmonic balance method. The disadvantage of the approach is small parameter assumption is needed. In order to improve the accuracy of the approximate solution, the residual of the former order harmonic approximation is introduced. Besides, we compare the second-order spreading residue harmonic balance method solution with the numerical one by the Runge–Kutta method. This proves the availability and validity of spreading residue harmonic balance method.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A two-degree-of-freedom coupled Duffing system with time delay is studied by a modified homotopy analysis method. First, a detailed calculation is given for the system. Second, single periodic and ...period-doubling solutions are obtained by solving the constructed nonlinear algebraic equation. Third, upon comparison of the periodic solution obtained by the multi-frequency homotopy analysis method with the numerical solutions obtained by the numerical method, it is found that the approximate solution agrees well with the numerical solution for the system. Finally, we discuss the convergence control parameters and convergence control function.
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Regarding the dynamic behavior of the functionally graded materials (FGM) conical panels under the static and harmonic in-plane loading, most studies focus on parametric resonances and dynamic ...instability which determine the stability regions. Studies on the bursting oscillation of the conical panels under the lower frequency excitation are quite rare. In this paper, we present a novel nonautonomous system of the cantilever functionally graded materials sandwich conical panels with a slowly varying parametric excitation and study the bending-torsion coupling bursting oscillations. The face sheets and core layer are the metal ceramic composite layer and homogeneous metal layer, respectively. In two surfaces layers, the component materials are gradually changed in the transverse direction and the temperature dependent properties show the form of the power law distribution. The excitations in the meridional direction include the static preload and lower frequency harmonic excitation. The mode functions of the first-order bending mode and the first-order torsion mode are obtained in terms of Chebyshev polynomials with the help of energy principle. The bending-torsion coupling nonautonomous nonlinear oscillation system is derived by Lagrange equations. Under the slowly varying in-plane load, the equilibrium solutions of the system are obtained by treating them as a generalized autonomous system and they will be no longer stable through the pitchfork bifurcation with the symmetry breaking. The bursting oscillations of the novel dynamic system are analyzed by numerical methods. It is interesting to find that the mechanisms of bursting oscillation are associated with the pitchfork bifurcation with the symmetry breaking.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Evolutionary, pattern forming partial differential equations (PDEs) are often derived as limiting descriptions of microscopic, kinetic theory-based models of molecular processes (e.g., reaction and ...diffusion). The PDE dynamic behavior can be probed through direct simulation (time integration) or, more systematically, through stability/bifurcation calculations; time-stepper-based approaches, like the Recursive Projection Method Shroff, G. M. & Keller, H. B. (1993) SIAM J. Numer. Anal. 30, 1099-1120 provide an attractive framework for the latter. We demonstrate an adaptation of this approach that allows for a direct, effective ("coarse") bifurcation analysis of microscopic, kinetic-based models; this is illustrated through a comparative study of the FitzHugh-Nagumo PDE and of a corresponding Lattice-Boltzmann model.
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Leukocyte rolling and arrest on the vascular endothelium is a central event in normal and pathological immune responses. However, rigorous estimation of the fluid and surface forces involved in ...leukocyte-endothelial interactions has been difficult due to the particulate, non-Newtonian nature of blood. Here we present a Lattice-Boltzmann approach to quantify forces exerted on rolling leukocytes by red blood cells in a “virtual blood vessel.” We report that the normal force imparted by erythrocytes is sufficient to increase leukocyte binding and that increases in tangential force and torque can promote rolling of previously adherent leukocytes. By simulating changes in hematocrit we show that a close “envelopment” of the leukocyte by the red blood cells is necessary to produce significant changes in the forces. This novel approach can be applied to a large number of biological and industrial problems involving the complex flow of particulate suspensions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This work investigated the effect of a chelator-mediated bio-mimetic free radical treatment on repulping and flotation operations during the deinking of laser printed copy paper. A chelator-mediated ...free radical treatment was carried out at two different chemical levels and a two-step repulping method, which combined conventional alkaline repulping as well as free radical treatment, was also developed. Flotation trials were performed on each of these treated samples to separate ink particles. Results from image analysis and paper physical properties testing are presented, and the deinking efficiency for these different treatments is also compared. Results indicate that under properly controlled conditions, free radical treatment can perform better than conventional chemical deinking methods.
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Excess aluminum (Al) exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential link between chronic Al exposure and Alzheimer's disease. In the ...present study, we sought to evaluate the protective effects of the herbal medicine
Dipsacus asper extract against the cognitive impairment and overexpression of hippocampal β-amyloid protein (Aβ) induced by chronic Al exposure in rats. Vitamin E (VE) was used as a positive control. Following exposure to 0.3% aluminum chloride (AlCl
3) solution for 90 days in their drinking water, animals displayed a striking decrease (>80%) in step-through latency in the passive avoidance task and a significant increase (123%) in the number of Aβ immunoreactive cells in the hippocampus compared to controls. Al-exposed animals were then randomly assigned to receive vehicle,
Dipsacus asper extract (4 g/kg), or VE (40 mg/kg) treatment up to 5 months. Both
Dipsacus asper extract and VE significantly ameliorated animal's performance impairment in the passive avoidance task and suppressed the overexpression of hippocampal Aβ immunoreactivity. The effects of
Dipsacus asper extract, but not VE, increased with time of treatment. The present results suggest that
Dipsacus asper extract may possess therapeutic effects against Alzheimer's disease.
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The purpose of this work was to improve our current knowledge of the non-enzymatic mechanisms involved in brown rot fungal decay of wood, but also to improve our understanding of chelator-mediated ...reactions that may occur in other biological systems where low pH conditions may prevail. Several key steps (iron chelation and reduction) during early non-enzymatic wood decay processes have been studied by using electron spin resonance (ESR). It has been proposed that low molecular weight chelators as well as Fenton reagents are involved in brown rot decay, at least in early non-enzymatic stages. In this work, the binding between a catecholate model chelator and ferric iron was studied by ESR spectroscopy. The effects of the model chelator, Fenton reagents, as well as the reaction conditions on free radical generation were also studied using ESR spin-trapping techniques. The results indicate: (1) The relative quantity of the chelator–iron complex can be determined by measurement of the intensities of the characteristic
g=4.3 ESR signal. (2) The effects of the chelator:iron ratio, the pH, and other reaction parameters on the hydroxyl radical generation in a Fenton type system can be determined using ESR spin-trapping techniques. (3) Data support the hypothesis that superoxide radicals are involved in chelator-mediated Fenton processes.
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A mediated Fenton system has been evaluated for decolorization of several types of dyes. The result shows that the Fenton system with a dihydroxybenzoic acid (DHBA) chelator-mediator effectively ...reduced the color of a diluted solution of Carta Yellow RW liquid, Carta Yellow G liquid, and Cartasol Red 2GF liquid dye to a colorless level after 90 minutes of treatment with 100 μM iron II (FeII), 100 μM DHBA, and 10 mM hydrogen peroxide$({\rm H}_{2}{\rm O}_{2})$at room temperature. Our results show that compared to a neat Fenton process, the mediated Fenton decolorization process increased the production, and therefore the effective longevity, of hydroxyl radical (OH) species to increase the decolorization efficiency. Our results suggest that application of this system would also result in an increase in dissolved oxygen (DO) in solution, which in turn would result in reduction of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total organic carbon (TOC).
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