Investigations of the Effects of Salt and Biopolymer Ratio on Sodium Caseinate-Xanthan Interactions in Aqueous Solution and Emulsions

The aim of this work was to investigate interactions that can take place between, proteins and polysaccharides, in the presence of electrolytes. Thus, our objective was to study the influence of NaCl addition on the associative and/or segregative interactions in the case of biopolymer mixtures and fine emulsions stabilized by sodium caseinate, by analysis of the rheological properties and zeta potential. From the experimental results, it was shown that the presence of salt affects the rheological and physicochemical properties of the aqueous phase and consequently the emulsion stability. Indeed, the electrolytes can modify the conformation of proteins and polysaccharides, by electric neutralization of their charge, as they can generate a complex coacervation or increase their incompatibility.     

Modeling of fixed-bed adsorption of Cs+ and Sr2+ onto clay–iron oxide composite using artificial neural network and constant–pattern wave approach

A low-cost, non-toxic and effective adsorbent constituted by a montmorillonite coated by iron oxides (montmorillonite–iron oxide composite) was prepared to assess its effectiveness in the removal of Cs⁺ and Sr²⁺ from aqueous solution. Dynamic adsorption experiments were carried out at room temperature under the effect of various operating parameters such as bed depth Z (5–15 cm), initial cation concentration C ₀ (2–50 mg L^?1) and volumetric flow rate Q (0.5–8 mL min^?1). Column performance has been modeled with constant-pattern wave approach combined to the Freundlich isotherm model and artificial neural network (ANN) models. The time, initial cation concentration, bed depth and volumetric flow rate were chosen as the input variables whereas, the outlet concentration C _t was considered as the output variable. The developed network was found to be useful in predicting the breakthrough curves. Experimental data for the used system were well fitted with ANN than the combined constant–pattern wave approach.     

Energy harvesting using hybridization of dielectric nanocomposites and electrets

Electrostrictive polymers have been investigated as electroactive materials for electromechanical energy harvesting. This kind of material is isotope, i.e. there is no permanent polarization compared with piezoelectric material, so in order to ensure its polarization and scavenging energy, the electrostrictive polymers need necessarily an application of a static field. To avoid this problem, we used the hybridization of electrostrictive polymer with electret. The present work aims an analytical modeling for predicting the power convert when the material was mechanically excited. The study was carried out on polyurethane and terpolymer [P(VDF–TrFE–CFE)] films, either without filler or filled with carbon nanopowder. Experimental measurements of the harvested power showed a good agreement with the theoretical behavior predicted by the proposed model. It was also shown that the incorporation of nanofillers increased the power harvested from 5.22 · 10^?2 to 1.498 · 10^?1 μW cm^?3 and from 6.87 · 10^?1 to 1.76 μW cm^?3 in polyurethane and in the terpolymer, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Existence theory for perturbed impulsive hyperbolic differential inclusions with variable times

In this paper, the existence of solutions for a perturbed impulsive hyperbolic differential inclusion with variable times is proved under the mixed generalized Lipschitz and Carathéodory's conditions.     

Synthesis,Acidity Constants and Tautomeric Structure of 7‐Arylhydrazono[1,2,4]Triazolo[3,4‐b][1,3,4]thiadiazines in Ground and Excited States

7‐Arylhydrazono[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazines 4 were synthesized from the reactions of 4‐amino‐5‐phenyl‐4H‐[1,2,4]triazole‐3‐thiol 2 and 2‐(2‐naphthyl)‐2‐oxoethanehydrazonoyl bromides 1 and their acid dissociation constants pK and pK*, in the ground and excited states, respectively, were determined. Both pK and pK* constants were correlated by Hammett equation. The pK and the spectral data presented indicate that the title compounds exist predominantly in the hydrazone tautomeric form.     

Combinatorial optimization and Green Logistics

The purpose of this paper is to introduce the area of Green Logistics and to describe some of the problems that arise in this subject which can be formulated as combinatorial optimization problems. The paper particularly considers the topics of reverse logistics, waste management and vehicle routing and scheduling.     

Application of lower bound direct method to engineering structures

Direct methods provide elegant and efficient approaches for the prediction of the long-term behaviour of engineering structures under arbitrary complex loading independent of the number of loading cycles. The lower bound direct method leads to a constrained non-linear convex problem in conjunction with finite element methods, which necessitates a very large number of optimization variables and a large amount of computer memory. To solve this large-scale optimization problem, we first reformulate it in a simpler equivalent convex program with easily exploitable sparsity structure. The interior point with DC regularization algorithm (IPDCA) using quasi definite matrix techniques is then used for its solution. The numerical results obtained by this algorithm will be compared with those obtained by general standard code Lancelot. They show the robustness, the efficiency of IPDCA and in particular its great superiority with respect to Lancelot.     

Sequences of nonlinear differential equations with related solutions

Summary A second-order nonlinear differential equation which occurs (together with variants of it) in many problems of applied mathematics, physics and engineering is here reduced to a first-order equation. This equation contains a parameter which is a quadratic rational function of two parameters appearing in the original equation. By applying a certain identity for a quadratic rational function, two (finite or infinite) sequences of nonlinear differential equations are generated whose solutions are determinable whenever the solution of any equation belonging to a sequence is known. The cases amenable to exact solution by quadrature are given. Entrata in Redazione il 16 luglio 1968.     

Energy Decay Rate of Solutions for the Wave Equation with Singular Nonlinearities

In this paper, we study the initial boundary value problem of the wave equation with singular nonlinearities of the form $$u_{tt}-u_{xx}+\sigma(t)|u|^{-r}g(u_{t})+|u|^{-\alpha}u=0\quad\hbox{in}\ I\times \mathbb{R}_+.$$ We prove decay estimates using multiplier method and weighted integral inequalities. We show that the energy of the system is bounded above by a quantity, depending on ??,g,r and ??, which tends to zero (as time goes to infinity). We give many significant examples to illustrate how to derive from our general estimates the polynomial, exponential or logarithmic decay.     

A new five-unknown refined theory based on neutral surface position for bending analysis of exponential graded plates

In the present paper, a new sinusoidal higher-order plate theory is developed for bending of exponential graded plates. The effects due to transverse shear and normal deformations are both included. The number of unknown functions involved in the present theory is only five as against six or more in case of other shear and normal deformation theories. The theory accounts for sinusoidal distribution of the transverse shear strains, and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factor. Based on the sinusoidal shear and normal deformation theory, the position of neutral surface is determined and the governing equilibrium equations based on neutral surface are derived. There is no stretching–bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. Numerical results of present theory are compared with three-dimensional elasticity solutions and other higher-order theories reported in the literature. It can be concluded that the proposed theory is accurate and efficient in predicting the bending response of exponential graded plates.