Heterogeneous Binary Systems Research Articles

Wormhole effective mass and gravitational waves by binary systems containing wormhole

We considered the generation of gravitational waves by the binary system associated with a wormhole. In the Newtonian limit, the gravitational potential of a wormhole requires the effective mass of the wormhole taking into account radial tension effects. This definition allows us to derive gravitational wave production in homogeneous and heterogeneous binary systems. Therefore, we studied gravitational waves generation by orbiting wormhole–wormhole and wormhole–black hole binary systems before coalescence. Cases involving negative mass require more careful handling. We also calculated the energy loss to gravitational radiation by a particle orbiting around the wormhole and by a particle moving straight through the wormhole mouth, respectively.

Interrogation of bimetallic particle oxidation in three dimensions at the nanoscale.

An understanding of bimetallic alloy oxidation is key to the design of hollow-structured binary oxides and the optimization of their catalytic performance. However, one roadblock encountered in studying these binary oxide systems is the difficulty in describing the heterogeneities that occur in both structure and chemistry as a function of reaction coordinate. This is due to the complexity of the three-dimensional mosaic patterns that occur in these heterogeneous binary systems. By combining real-time imaging and chemical-sensitive electron tomography, we show that it is possible to characterize these systems with simultaneous nanoscale and chemical detail. We find that there is oxidation-induced chemical segregation occurring on both external and internal surfaces. Additionally, there is another layer of complexity that occurs during the oxidation, namely that the morphology of the initial oxide surface can change the oxidation modality. This work characterizes the pathways that can control the morphology in binary oxide materials.

Formation of protective coatings on metals by intense pulsed ion beam

The results of the development of a combined method for protective coating deposition by plasma-generated ablation under the action of an intense pulsed ion beam (IPIB) on the surface of ablated materials are reported. This method deals with: cleaning of a substrate surface and thin Ti film deposition by the IPIB; radiation-induced mass transfer of elements of both the film and substrate to increase adhesion; deposition of thin Ti and C films by IPIB; and mixing of elements of this heterogeneous binary system by IPIB to create TiC coatings. The Ti film was deposited onto both Al and Fe, and then mixing was performed by IPIB using current density of 35 A/cm 2 with various numbers of pulses. The substrate temperature was 20–300 °C. Analysis of the elemental composition of the coating–substrate system was performed by the Rutherford backscattering method. After deposition of the main TiC coating at a substrate temperature of 300 °C, analysis of the elemental composition of the coating–substrate interface was performed using the Auger electron spectroscopy method. The microhardness was measured using the Vickers method.

Recent Advances in Olefin Polymerization Using Binary Catalyst Systems

Several homogeneous and heterogeneous binary systems have been applied to olefin polymerization in order to produce polymers with improved physical and/or chemical characteristics. This article reviews the recent developments in this area focusing mainly on polymer properties, the relationship between the types of catalyst present in the binary systems, their use in the homopolymerization of ethylene and propene, and the copolymerization of ethylene and higher α-olefins.

Effect of encapsulation in MCM-41 type molecular sieves on vibrational spectra of liquid crystalline state

The paper deals with the investigation of IR absorption spectra of a pure 4- n-pentyl-4′-cyanobiphenyl (5CB) liquid crystal in nematic liquid crystalline (LC) state, pure aluminosilicate molecular sieves of MCM-41 type (with channels about 40 Å in diameter) and their heterogeneous binary systems. It was shown that 5CB molecules are able to interact with active centers in the MCM-41 channels forming sufficiently strong hydrogen bonds of the —CN⋯H—O— type. This conclusion was confirmed by the data obtained from DSC measurements. Relative amount of the 5CB molecules interacting with the channel walls and that of the molecules retaining the LC state when encapsulated in molecular sieves MCM-41 and CuMCM-41 were estimated.

Phase equilibria in phospholipid-water systems

This work is a critical account of phase studies of phospholipid-water mixtures. The Phase Rule and equations of thermodynamics of heterogeneous systems are applied in the analysis of calorimetric and dilatometric results for these systems. It is inferred that the approach in which a lipid-water mixture of low lipid content is regarded as a one-component system is misleading and unhelpful. A mixture containing water and a pure synthetic phospholipid is a binary system, and the Phase Rule can be applied to it in a straightforward manner. Non-isothermal transitions and invariant three-phase reactions of the eutectic, peritectic and polytectic type can be encountered in lipid-water systems, like in other binary mixtures. The concentration dependence of the enthalpy of the isothermal three-phase transition yields a well-known Tammann triangle. For the volume change at such transition an analog of the Tammann triangle can be drafted which can be useful in interpretation of dilatometric and densitometric data for heterogeneous binary systems. The literature thermodynamic data for the aqueous lipids are analyzed on the basis of the phase diagram of the DPPC-water system. The measured values of the transition enthalpy and volume change at the pre- and main transitions refer to invariant phase reactions. The measured heat capacities and thermal coefficients of expansion actually characterize the biphasic lipid-water mixtures and may reflect phenomena specific for heterogeneous binary systems only. A reinterpretation of the literature DSC data for the DPPC-water system at temperatures below zero is suggested. Experience gained in the study of equilibrium phase diagram, kinetic and colloidal aspects of phase behaviour of dioctadecyldimethylammonium chloride-water system indicates that the common procedures of the sample preparation of lipid-water mixtures may lead to the states which are non-equilibrium in two respects: the system contains a metastable phase, and the phase is dispersed to such an extent that an irreversible colloidal structure is formed. Definitive phase studies of the phase behaviour of phospholipid-water systems in the whole concentration range are urgently needed.

Reaction diffusion in heterogeneous binary systems

Reaction diffusion in heterogeneous binary systems

Reaction diffusion in heterogeneous binary systems

A system of non-linear differential equations describing the growth kinetics of the two compound layers at the interface between two elements is proposed. A number of well-known experimental and theoretical relationships follows from this system in the limiting cases.

Reaction diffusion in heterogeneous binary systems

Reaction diffusion in heterogeneous binary systems

The Kinetics of Stable Heterogeneous Binary Systems

AbstractAmong thermodynamically stable systems homogeneous one‐phase states are compared with two‐phase heterogeneous ones, while no restriction is made about the physical origin of stability. In the case of transitions from a one‐phase state to another one‐phase state or a two‐phase system, a continuous spectrum of relaxation times appears as a difference to a transition from a two‐phase to another two‐phase state: in this latter case one finds two processes of distinctly different rates in good agreement, with experiment. With the aid of a stochastic theory, containing elements of classical nucleation and coarsening theory, the early, as well as the late kinetic change of the size distribution function as well as of momenta, describing the system, are derived. This theory also allows for a rise of the number of zones of a phase during annealing as a contrary effect to coarsening.

The prediction of the ternary liquid-liquid equilibrium by means of the NRTL-equation

The prediction of ternary liquid-liquid equilibria by means of the NRTL-equation and using the parameters obtained by the correlation of the limiting binary systems is examined. The predicted data are compared with experimental data for systems composed of an aromatic and an aliphatic hydrocarbon and sulpholane. The number of sets of binary parameters obtained from the correlation of the binary systems is infinite. For any value of the non-randomness parameter a corresponding pair of energy parameters can be determined, giving rise to a set fitting the data equally well. Limits to the value of the parameters can only vaguely be determined on the basis of their physical meaning. The upper limit of the non-randomness parameter related to the heterogeneous binary system is more precisely defined. Some general conclusions for the selection of the parameters could be reached. The predicted heterogeneous area is in general too large but decreases with increasing values of the non-randomness parameter of the heterogeneous binary system. The value of the parameters of the homogeneous binary system has only a small influence on the position of the binodal. The slope of the tie lines is mainly determined by the non-ideality of the homogeneous binary systems.

The prediction of the ternary liquid‐liquid equilibrium by means of the NRTL‐equation

AbstractThe prediction of ternary liquid‐liquid equilibria by means of the NRTL‐equation and using the parameters obtained by the correlation of the limiting binary systems is examined. The predicted data are compared with experimental data for systems composed of an aromatic and an aliphatic hydrocarbon and sulpholane. The number of sets of binary parameters obtained from the correlation of the binary systems is infinite. For any value of the non‐randomness parameter a corresponding pair of energy parameters can be determined, giving rise to a set fitting the data equally well. Limits to the value of the parameters can only vaguely be determined on the basis of their physical meaning. The upper limit of the non‐randomness parameter related to the heterogeneous binary system is more precisely defined. Some general conclusions for the selection of the parameters could be reached. The predicted heterogeneous area is in general too large but decreases with increasing values of the non‐randomness parameter of the heterogeneous binary system. The value of the parameters of the homogeneous binary system has only a small influence on the position of the binodal. The slope of the tie lines is mainly determined by the non‐ideality of the homogeneous binary systems.

Theoretical conditions for the existence of a dielectric relaxation due to Maxwell-Wagner effect in heterogeneous binary systems and especially in emulsions

The conditions for the existence of a dielectric relaxation due toMaxwell-Wagner effect in heterogeneous binary mixtures are derived from the general laws of electromagnetism. A dielectric relaxation can occur only if the time-constants of the components of the system are different from each other and different from zero as well, whichever be the geometry. This theoretical result is supported by experimental data concerning water-in-oil, oil-in-water, nitrobenzene-in-water and mercury-in-oil emulsions.