Stability of multiobjective NLP problems with fuzzy parameters in the objectives and constraints functions

This paper deals with the stability of multiobjective nonlinear programming problems with fuzzy parameters in the objectives and constraints functions. These fuzzy parameters are characterized by fuzzy numbers. The existing results concerning the qualitative analysis of the notions (solvability set, stability sets of the first kind and of the second kind) in parametric nonlinear programming problems are reformulated to study the stability of multiobjective nonlinear programming problems under the concept of α-pareto optimality. An algorithm for obtaining any subset of the parametric space which has the same corresponding α-pareto optimal solution is also presented. An illustrative example is given to clarify the obtained results.     

Graphs With Few Matching Roots

We determine all graphs whose matching polynomials have at most five distinct zeros. As a consequence, we find new families of graphs which are determined by their matching polynomials.     

ZL-amenability and characters for the restricted direct products of finite groups

Let G   be a restricted direct product of finite groups _{Gi}i∈I${\{G_i\}}_{i\in I}$, and let Z?¹(G)${\mathrm{Z}?}^1(G)$ denote the centre of its group algebra. We show that Z?¹(G)${\mathrm{Z}?}^1(G)$ is amenable if and only if _Gi$G_i$ is abelian for all but finitely many i  , and characterize the maximal ideals of Z?¹(G)${\mathrm{Z}?}^1(G)$ which have bounded approximate identities. We also study when an algebra character of Z?¹(G)${\mathrm{Z}?}^1(G)$ belongs to _c0$c_0$ or ?^p${?}^p$ and provide a variety of examples.     

On the Semiprimitivity of Skew Polynomial Rings

Let R be a semiprime left Goldie ring with a monomorphism and an α-derivation, then is semiprimitive left Goldie ring.     

Gelation and Swelling Behavior of Semi-Interpenetrating Polymer Network Hydrogels Based on Polyacrylamide and Poly(vinyl alcohol)

Novel semi-Interpenetrating Polymer Network (semi-IPN) hydrogels based on partially Hydrolyzed Polyacrylamide (HPAM) and Poly(Vinyl Alcohol) (PVA) were prepared by solution crosslinking using chromium triacetate. Effects of PVA content on the gelation process and swelling behavior in tap water and different electrolyte solutions were investigated. Study of the gelation behavior using dynamic rheometery showed that the limiting storage modulus of the semi-IPN gels decreased with increasing PVA content. It was also found that increasing the PVA content increases the loss factor, indicating that the viscous properties of this gelling system increase more strongly than the elastic properties. The swelling ratio of the semi-IPN gels in tap water decreased as the concentration of the PVA increased. However, the semi-IPN gels showed lower salt sensitivity factor in synthetic oil reservoir water as compared with HPAM gels. Therefore, they are potentially good candidates for enhanced oil recovery applications.     

Electrochemical behavior of Al2O3/Al composite coated Al electrodes through surface mechanical alloying in alkaline media

The behavior of $A{l}_2{O}_3/Al$ composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media $2MKOH$ were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with $A{l}_2{O}_3$ until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al₂O₃ to stable tetrahedral $Al{\left(OH\right)}_4^{?}$ aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction.     

A cellular uptake and cytotoxicity properties study of gallic acid-loaded mesoporous silica nanoparticles on Caco-2 cells

In this study, the effects of intracellular delivery of various concentrations of gallic acid (GA) as a semistable antioxidant, gallic acid-loaded mesoporous silica nanoparticles (MSNs-GA), and cellular uptake of nanoparticles into Caco-2 cells were investigated. MSNs were synthesized and loaded with GA, then characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, N₂ adsorption isotherms, X-ray diffraction, and thermal gravimetric analysis. The cytotoxicity of MSNs and MSNs-GA at low and high concentrations were studied by means of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test and flow cytometry. MSNs did not show significant toxicity in various concentrations (0–500 μg/ml) on Caco-2 cells. For MSNs-GA, cell viability was reduced as a function of incubation time and different concentrations of nanoparticles. The in vitro GA release from MSNs-GA exhibited the same antitumor properties as free GA on Caco-2 cells. Flow cytometry results confirmed those obtained using MTT assay. TEM and fluorescent microscopy confirmed the internalization of MSNs by Caco-2 cells through nonspecific cellular uptake. MSNs can easily internalize into Caco-2 cells without deleterious effects on cell viability. The cell viability of Caco-2 cells was affected during MSNs-GA uptake. MSNs could be designed as suitable nanocarriers for antioxidants delivery.     

Matrix Heterogeneity Effects on Gas Transport and Adsorption in Coalbed and Shale Gas Reservoirs

In coalbeds and shales, gas transport and storage are important for accurate prediction of production rates and for the consideration of subsurface greenhouse gas sequestration. They involve coupled fluid phenomena in porous medium including viscous flow, diffusive transport, and adsorption. Standard approach to describe gas–matrix interactions is deterministic and neglects the effects of local spatial heterogeneities in porosity and material content of the matrix. In this study, adopting weak-noise and mean-field approximations and using a statistical approach in spectral domain, matrix heterogeneity effects are investigated in the presence of non-equilibrium adsorption with random partition coefficient. It is found that the local heterogeneities can generate non-trivial transport and kinetic effects which retard gas release from the matrix and influence the ultimate gas recovery adversely. Macro-transport shows 1/[1 + N _Pe /(1 + N _Pe )] dependence on the Péclet number, and persists at the diffusive ultra-low permeability limit. Macro-kinetics is directly related to Thiele modulus by the following expression: N _Th /(1 + 2N _Pe ). It leads to trapping of gas in the adsorbed phase during its release from the matrix, and to an adsorption threshold during the gas uptake by the matrix. Both effects are proportional to the initially available adsorbed gas amount and becomes more pronounced with the increasing variance of the porosity field. Consequently, a new upscaled deterministic gas mass balance is proposed for practical purposes. Numerical results are presented showing free and adsorbed gas distributions and fractional gas sorption curves for unipore coal matrix exhibiting Gaussian porosity distribution. This study is a unique approach for our further understanding of the coalbeds and gas shales, and it is important for the development of sound numerical gas production and sequestration models.     

Numerical study of induction heating in melt growth systems—Frequency selection

A set of 2D finite element numerical simulation of induction heating process for an oxide Czochralski crystal growth system has been made for a range of f=1–100 kHz applied frequency of driving current. It was shown that the frequency selection has a marked effect in all basic induction phenomena, including electromagnetic field distribution, skin depth, coil efficiency, and intensity and structure of heating in the growth setup.