Niobia/alumina model catalysts were prepared by physical vapor deposition of Nb in an oxygen atmosphere onto thin alumina films. Structural characterization, performed with scanning tunneling microscopy and infrared reflection absorption spectroscopy, revealed highly dispersed N2O5 nanoparticles exposing Nb=O groups. Thermal stability of the system was also examined. The results are compared wi...

This paper investigates the parametric study of the empty and foam-filled end-capped tubes under quasi static and dynamic loadings. The numerical crash analysis of the empty and foam-filled tubes was performed using the explicit finite element code ABAQUS- explicit. Satisfactory agreements were generally achieved between the numerical and experimental results. In order to determine the crash be...

Cracks free mullite-alumina Functionally Gradient Ceramics (FGC) have been obtained by sequential slip casting of Mullite-alumina slurries with diserent mullite/alumina ratios. These slurries were prepared with 65 % solids content and viscosities rangingpom 10 to 40 mPa.s. 7he presence of cracks perpendicular to the FGC layers have been attributed to residual stresses developed because of the m...

Co-synthesis of In2O3 and ZnO nanowires (NWs) were grown on silicon and alumina substrates using vapour transport deposition method. Their morphological structures showed that the NWs were rather aligned on silicon substrate and randomly oriented on alumina substrate. The formation of NWs on silicon substrate was found to be dominated by the growth of ZnO NWs while that on alumina substrate was...

Abstract: Enhanced foam flooding is a chemical flooding technology, which is applied to improve the recovery efficiency of oil and gas. The oil displacement agent of enhanced foam flooding is a foam that the polymer and surfactant solution as liquid. In this paper, three-dimensional mathematical model of unsteady flow is established about enhanced foam system in the porous media, and the numeri...

Liquid foams have important practical applications. To analyze the dependence of foam behavior on material properties, and to improve foam models, foam scientists work with dozens of related simulations obtained by varying these material properties as well as parameters such as foam attributes, properties of objects interacting with foam or shape of foam containers. We present visualization sol...

Foam dynamics is gaining interests within Computational Fluid Dynamics and Computer Graphics. We believe that liquid foam, or froth, is the next evolution in the field of fluid dynamics. Froth is the natural phenomenon of bubbles that arise due to nucleation of gas in liquids. As the physics of foams in two dimensions is better understood this thesis begins the journey of physics-based foam dyn...

This investigation presents the effect of various parameters on foam stability and its rheological properties. The underlying idea of this experiment is generating of drilling foam with uniform bubbles. The main problem of foam using is controlling its stability during field application. The most important parameters which cause Instability in foam are gravity drainage, gas diffusion and bubble...

Semi-buried structures are most commonly used at first line of defense along the border between two countries. This demands investigation of their dynamic behaviour under blast loading. Herein, a semi-buried structure with foam sandwiched walls and buttresses to reduce the effect of blast is analysed. The effect of provision of different configurations of buttresses and foam core between two la...

Milk-based espresso coffee is one of the most popular beverages. Foam is an essential quality characteristic for this beverage. Foam formation and stability is mainly related to the milk composition. In this study the influence of three different concentrations of Xanthan gum (0.05, 0.1 and 0.2 g dm-3) and three different temperatures (50, 60 and 70 °C) on foam stability were examined and exper...