Instability through porous media of three layers superposed conducting fluids

The instability properties of streaming superposed conducting fluids through porous media under the influence of uniform magnetic field have been investigated. The system is composed of a middle fluid sheet of finite thickness embedded between two semi-infinite fluids. The fluids are assumed to be incompressible, perfectly conducting and there are weak viscous stresses on the interfaces. The Rayleigh–Taylor and Kelvin–Helmholtz problems have been studied. Such configurations are of relevance in a variety of astrophysical and space configurations. The solutions of the linearized equations of motion together with the boundary conditions lead to deriving the dispersion equation with complex coefficients. The limiting case of the stability of one interface between two fluids has been discussed. The stability criteria are discussed theoretically and numerically in which stability diagrams are obtained. It has been found that the increase of the viscosity coefficient as well as the porosity plays a regular stabilizing role in the stability behavior, while the increase of the fluid velocity plays a destabilizing influence in the stability criteria.     

Stability of resonant interfacial waves in the presence of uniform magnetic field

The aim of this work is to study the instability of interacting waves between two immiscible magnetic liquids. The effects of gravitation and a uniform normal magnetic field are taken into account. The method of multiple scales is used to determine the stability criteria of the considered problem. The various stability criteria are discussed both analytically and graphically. According to the numerical examples, we have remarked that the increase of the ratio of the permeability of the liquids appears to be the destabilizing effect of the magnetic field. The short waves below the critical wavenumbers are stable whereas a number of long waves are unstable. The viscosity effect on the stability criteria is a dual-role one, depending on the strength of the applied magnetic field.     

Long waves between a subsonic gas flow-film interface flowing down an inclined plate

The present work deals with temporal stability properties of a falling liquid film down an inclined plane in the presence of a parallel subsonic gas flow. The waves are described by evolution equation previously derived as a generalization of the model for the Newtonian liquid. We confirm linear stability results of the basic flow using the Orr–Sommerfeld analysis to that obtained by long wave approximation analysis. The non-linear stability criteria of the model are discussed analytically and stability branches are obtained. Finally, the solitary wave solutions at the liquid–gas interface are discussed, using specially envelope transform and direct ansatz approach to Ginzburg–Landau equation. The influence of different parameters governing the flow on the stability behavior of the system is discussed in detail.     

Impact of the slip condition on the resonance of a film flow over an inclined slippery topography plate

Meccanica - This study addresses the linear and nonlinear resonance of the film flow on an inclined slippery topography plate in the frame of long-wave theory. The influence of the surface tension...     

An operationally simple,one-pot,convenient synthesis,and in vitro anti-inflammatory activity of some new spirotriazolotriazine derivatives

The wide biological actions of triazolotriazine hybrids, benzene-sulfonamide derivatives, exhibit a good chance of displaying in vitro anti-inflammatory effects. An operationally simple one-pot, three-component, and convenient synthesis method is used toward the synthesis of a series of diverse 2-(2-(4-amino)-1,3,5-triazaspiro-1,4-dien-2-yl) hydrazinyl)-N-(4-sulfamoylphenyl)-2-thioxoacetamides, which generated via reaction of 2-hydrazinyl-N-(4-sulfamoylphenyl)-2-thioxoacetamide, cyanoguanidine, and cyclic/acyclic ketones and were characterized by spectral analysis (IR, Nuclear Magnetic Resonance: ¹H-NMR, ¹³C-NMR, and elemental analysis). The spirotriazolotriazine derivatives are obtained with up to 95% yield, and their structure–activity relationship was discussed. All compounds were tested for in vitro anti-inflammatory potential using the inhibition of RBC hemolysis technique and COX inhibition assay. The results from RBC hemolysis technique demonstrated that almost all evaluated compounds exhibited significant in vitro anti-inflammatory efficacy. More specifically, compounds 7, 8 , and 12 have superior membrane stability over indomethacin as a standard drug. At concentrations of 400, 600, 800, and 1000 μg/mL, compound 12 demonstrated highly significant inhibition of RBC hemolysis with 95.2%, 97.3%, 98.9%, and 99.8%, respectively, compared with indomethacin at the same concentrations (94.5%, 97.3%, 98.5%, and 99.3%, respectively). COX assay indicated that compounds 7, 8, and 12 exhibited excellent COX-2 inhibition percentage (98.51 ± 0.01, 98 ± 0.01, and 98.97 ± 0.06, respectively) at 150 μg/mL using indomethacin (97.3 ± 0.005). Furthermore, an investigation using molecular docking against COX-2 (pdb ID: 5IKT) was used to analyze the anti-inflammatory properties of all studied substances. When compared to indomethacin, molecular docking research showed a strong connection with the intended protein and an elevated docking score. According to in vitro anti-inflammatory action and computational approach, they show promise as a therapeutic candidate for the treatment of inflammatory diseases.     

Nonlinear evolution of the travelling waves at the surface of a thin viscoelastic falling film

The problem of hydrodynamic instability of a thin condensate viscoelastic liquid film flowing down on the outer surface of an axially moving vertical cylinder is investigated. In order to improve the accuracy of numerical results, the viscoelastic and heat transfer parameters have been included into the governing equations. Also, the analytical solutions are obtained by utilizing the long-wave perturbation method. The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem. It has been revealed that the stability of the film flow is weakened when the radius of cylinder and the temperature difference are reduced. Moreover, it is found that the increment of down-moving motion of the cylinder can enhance the flow stability. Further, the thin film flow can be destabilized by the viscoelastic property. The results show that both supercritical stability and subcritical instability can take place within the film flow system given appropriate conditions. Moreover, the absence of Reynolds number leads to an obvious difference in the behavior of some physical parameters.     

Structural and chemical properties of the nitrogen-rich energetic material triaminoguanidinium 1-methyl-5-nitriminotetrazolate under pressure

The structural and chemical properties of the bi-molecular, hydrogen-bonded, nitrogen-rich energetic material triaminoguanidinium 1-methyl-5-nitriminotetrazolate C(3)H(12)N(12)O(2) (TAG-MNT) have been investigated at room pressure and under high pressure isothermal compression using powder x-ray diffraction and Raman and infrared spectroscopy. A stiffening of the equation of state and concomitant structural relaxation between 6 and 14 GPa are found to correlate with Raman mode disappearances, frequency discontinuities, and changes in the pressure dependence of modes. These observations manifest the occurrence of a reversible martensitic structural transformation to a new crystalline phase. The onset and vanishing of Fermi resonance in the nitrimine group correlate with the stiffening of the equation of state and phase transition, suggesting a possible connection between these phenomena. Beyond 15 GPa, pressure induces irreversible chemical reactions, culminating in the formation of a polymeric phase by 60 GPa.     

Long interfacial waves inside an inclined permeable channel

The time evolution of superposed layers of fluid flowing down inside an inclined permeable channel is investigated. Using the Kármán-Pohlhausen approximation, the problem is reduced to the study of the evolution equation for the liquid–liquid interface of the liquids film derived through a long-wave approximation. A linear stability analysis of the base flow is performed. The solutions and stability of the non-linear stationary long waves are investigated. A special form of the stationary long waves (say Shkadov waves) is introduced.     

Effect of Gamma Radiation on the Electrical Resistivity of Some Metal Acetylacetonate Complexes

The effect of gamma radiation on the electrical resistivity of some lanthanide and alkali acetylacetonate complexes was studied for differet doses (20-49 – 36-2 Mr). The activation energy for each complexes was calculated. The obtained results showed that the resistivity as well as the activation energy increase with increasing the radiation dose. An empirical linear relation between the rate of change of resistivity with radiation dose and the ionic radius of the metal was obtained.     

Entropy squeezing of multi-photon field interacting with a single Cooper-pair box

We investigate the entropy squeezing and entanglement of the Cooper-pair box interacting with multi-photon cavity field. The field is prepared initially in the coherent state, while the Cooper-pair box is assumed to start from a mixed state. We find that the number of photons and the detuning parameters play an important role in the entropy squeezing and entanglement. We observe that the entropy squeezing can be used as a good indicator of the entanglement. This study opens promising perspectives for creating remote quantum information processing networks.