A problem of prescribing Gaussian curvature on

A class of functions and the corresponding solutions of

are obtained as a special case of the solutions of

where is defined as .

     

Removal of copper from aqueous solutions by adsorption on activated carbons

The adsorption isotherms of Cu(II) ions from aqueous solutions in the concentration range 40–1000 mg l⁻¹ on two samples of granulated and two samples of activated carbon fibres containing varying amounts of associated oxygen have been reported. The adsorption isotherms are type I of BET classification showing initially a rapid adsorption tending to be asymptotic at higher concentrations. The amounts of oxygen associated with the carbon surface has been enhanced by oxidation with nitric acid and ammonium persulphate in the solution phase and with oxygen gas at 350°C and decreased by degassing of the oxidized carbon samples at 400, 650 and 950°C. The adsorption of Cu(II) ions increases on oxidation and decreases on degassing. The increase in adsorption on oxidation depends on the nature of the oxidative treatment while the decrease in adsorption on degassing depends on the temperature of degassing. This has been attributed to the increase in the carbon–oxygen acidic surface groups on oxidation and their decrease on degassing. Suitable mechanisms consistent with the results have been proposed.     

Lie-optic matrix algorithm for computer simulation of paraxial self-focusing in a plasma

Propagation algorithm for computer simulation of stationary paraxial self-focusing laser beam in a medium with saturating nonlinearity is given in Lie-optic form. Accordingly, a very natural piece-wise continuous Lie transformation that reduces to a restricted Lorentz group of the beam results. It gives rise to a matrix method for self-focusing beam propagation that is constructed and implemented. Although the results use plasma nonlinearities of saturable type, and a gaussian initial beam, these results are applicable for other media like linear optical fibers and to more general situations.     

Exploring binding properties of gliclazide with human serum albumin

Journal of Thermal Analysis and Calorimetry - The thermodynamic parameters of the binding of gliclazide (GL) with human serum albumin (HSA) have been discussed along with the insight into the...     

On the Fučik spectrum of non-local elliptic operators

In this article, we study the Fu?ik spectrum of the fractional Laplace operator which is defined as the set of all \({(\alpha, \beta)\in \mathbb{R}^2}\) such that $$\quad \left.\begin{array}{ll}\quad (-\Delta)^s u = \alpha u^{+} - \beta u^{-} \quad {\rm in}\;\Omega \\ \quad \quad \quad u = 0 \quad \quad \quad \qquad {\rm in}\; \mathbb{R}^n{\setminus}\Omega.\end{array}\right\}$$ has a non-trivial solution u, where \({\Omega}\) is a bounded domain in \({\mathbb{R}^n}\) with Lipschitz boundary, n > 2s, \({s \in (0, 1)}\) . The existence of a first nontrivial curve \({\mathcal{C}}\) of this spectrum, some properties of this curve \({\mathcal{C}}\) , e.g. Lipschitz continuous, strictly decreasing and asymptotic behavior are studied in this article. A variational characterization of second eigenvalue of the fractional eigenvalue problem is also obtained. At the end, we study a nonresonance problem with respect to the Fu?ik spectrum.     

Structure and transport properties of polymer grafted nanoparticles

We perform molecular dynamics simulations on a bead-spring model of pure polymer grafted nanoparticles (PGNs) and of a blend of PGNs with a polymer melt to investigate the correlation between PGN design parameters (such as particle core concentration, polymer grafting density, and polymer length) and properties, such as microstructure, particle mobility, and viscous response. Constant strain-rate simulations were carried out to calculate viscosities and a constant-stress ensemble was used to calculate yield stresses. The PGN systems are found to have less structural order, lower viscosity, and faster diffusivity with increasing length of the grafted chains for a given core concentration or grafting density. Decreasing grafting density causes depletion effects associated with the chains leading to close contacts between some particle cores. All systems were found to shear thin, with the pure PGN systems shear thinning more than the blend; also, the pure systems exhibited a clear yielding behavior that was absent in the blend. Regarding the mechanism of shear thinning at the high shear rates examined, it was found that the shear-induced decrease of Brownian stresses and increase in chain alignment, both correlate with the reduction of viscosity in the system with the latter being more dominant. A coupling between Brownian stresses and chain alignment was also observed wherein the non-equilibrium particle distribution itself promotes chain alignment in the direction of shear.