Appearance of a Solitary Wave Particle Concentration in Nanofluids under a Light Field

In this study, the nonlinear dynamics of nanoparticle concentration in a colloidal suspension (nanofluid) were theoretically studied under the action of a light field with constant intensity by considering concentration convection. The heat and nanoparticle transfer processes that occur in this case are associated with the phenomenon of thermal diffusion, which is considered to be positive in our work. Two exact analytical solutions of a nonlinear Burgers-Huxley-type equation were derived and investigated, one of which was presented in the form of a solitary concentration wave. These solutions were derived considering the dependence of the coefficients of thermal conductivity, viscosity, and absorption of radiation on the nanoparticle concentration in the nanofluid. Furthermore, an expression was obtained for the solitary wave velocity, which depends on the absorption coefficient and intensity of the light wave. Numerical estimates of the concentration wave velocity for a specific nanofluid—water/silver—are given. The results of this study can be useful in the creation of next-generation solar collectors.

Self-toughened high entropy alloy with a body-centred cubic structure

Multi-scale deformation structure & evolution analysis of strong-yet-ductile interstitially hardened alloy, exhibiting a two-step phase transformation and concentration wave strengthening.

Out-of-equilibrium dynamics of photoexcited spin-state concentration waves

The spin crossover compound [FeIIH2L2-Me][PF6]2 presents a two-step phase transition. In the intermediate phase, a spin state concentration wave (SSCW) appears resulting from a symmetry breaking (cell doubling) associated with a long-range order of alternating high and low spin molecular states. By combining time-resolved optical and X-ray diffraction measurements on a single crystal, we study how such a system responds to femtosecond laser excitation and we follow in real time the erasing and rewriting of the SSCW.

Outflow Curve and its Simulation for a Class of Reaction Chromatography with Gradual Changed Head-On Injection

The reaction chromatography model for a reaction was established based on fluid dynamics theory of the chromatographic process. The gradual changed head-on injection was taken as an example, using the characteristics method of hyperbolic partial differential equations, the concentration wave solutions for reactant and resultant were derived, the behavior of outflow curves was clarified, and the simulation of outflow curves was performed. The results provided the proper theory models for further chromatographic analysis.

Effect of kinesin velocity distribution on slow axonal transport

The goal of this paper is to investigate the effect that a distribution of kinesin motor velocities could have on cytoskeletal element (CE) concentration waves in slow axonal transport. Previous models of slow axonal transport based on the stop-and-go hypothesis (P. Jung, A. Brown, Modeling the slowing of neurofilament transport along the mouse sciatic nerve, Physical Biology 6 (2009) 046002) assumed that in the anterograde running state all CEs move with one and the same velocity as they are propelled by kinesin motors. This paper extends the aforementioned theoretical approach by allowing for a distribution of kinesin motor velocities; the distribution is described by a probability density function (PDF). For a two kinetic state model (that accounts for the pausing and running populations of CEs) an analytical solution describing the propagation of the CE concentration wave is derived. Published experimental data are used to obtain an analytical expression for the PDF characterizing the kinesin velocity distribution; this analytical expression is then utilized as an input for computations. It is demonstrated that accounting for the kinesin velocity distribution increases the rate of spreading of the CE concentration waves, which is a significant improvement in the two kinetic state model.