Variational Formulation and Numerical Implementation of Diffusion in Hydrogels at Finite Strains

Hydrogels are polymeric materials with a cross-linked network which can absorb water. Due to their bio-compatibility, hydrogels have many applications in biology and medicine. Recently modeling the mechanical behavior of hydrogels has attracted a great deal of attention among researchers, see e.g., [1] and [2]. Following our previous works [3], [4] and [5] we now present a variational framework for swelling phenomenon in hydrogels. The variational formulation of the problem can be done using a saddle-point principle or a minimization principle. Saddle-point principle has to fulfill the Ladyzhenskaya-Babuška-Brezzi (LBB) condition in order to lead to a stable finite element scheme. The key aspect of our proposed minimization principle is its advantage with regard to an unconstrained fem implementation. In this work we aim to compare the numerical performance of these two variational formulations for swelling of hydrogels. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nonlinear Alternatives of Leray-Schauder Type in Banach Algebra Involving Four Operators with Application

In this article, we prove some fixed point theorems of Leray-Schauder Type in Banach Algebra satisfying certain sequential condition (𝒫) for the sum and the product of nonlinear weakly sequentially continuous operators and we give an example of application to a functional nonlinear integral equation.     

Gamma Irradiation Effects on the Electric Conductivity Behaviour and IR Absorption Spectra of some Haloacetato and Mixed Thiazoles-Haloacetato Transition Metal Complexes

Gamma irradiation effects on the electric conductivity behaviour and IR absorption spectra of some thiazole and haloacetato complexes were investigated. A comparison is made between the rate and activation energies of the thermal annealing of electrical properties of pure and γ-irradiated samples. A mechanism is suggested to explain the observed decrease in the intensity of metal-oxygen bond in the IR spectra of the complexes as a result of γ-irradiation.     

Wormholes in Jackiw—Teitelboim Gravity

Theoretical and Mathematical Physics - We investigate various aspects of AdS2 wormholes in Jackiw—Teitelboim gravity and their holographic applications. We first study the AdS2 space in...     

Breaking anonymity of some recent lightweight RFID authentication protocols

Wireless Networks - Due to their impressive advantages, Radio Frequency IDentification (RFID) systems are ubiquitously found in various novel applications. These applications are usually in need of...     

Toughening of Poly(ethylene terephtalate) (PET) Bottle Wastes by Modified Styrene-Butadiene Rubber (SBR) Elastomer

Summary: Modified SBR was blended with dried PET bottle wastes in an internal mixer. During the process mechanical and morphological properties were studied. When PET bottle wastes were blended with unmodified SBR, the final blend had a rough morphology and low impact strength. In contrary, blending of PET with modified SBR lead to smooth and fine morphology. Utilizing grafted SBR in PET blends creates an enormous difference in particle size and morphology, which is a result of powerful interactions and effective chemical bonding between the components of the blend. The final product had high impact strength in comparison with PET and unmodified SBR blend. These results are mainly related to formation in situ of PET/SBR graft copolymer in interface, which is produced by chemical reaction among active maleic anhydride groups and active PET groups.