Dispersive Media Research Articles

Konjac glucomannan foams integrated with bilayer phase change microcapsules for efficient heat storage and thermal insulation.

Konjac glucomannan foams integrated with bilayer phase change microcapsules for efficient heat storage and thermal insulation.

Resonant lump chain interactions of a (2+1)-dimensional generalized Korteweg–de Vries equation in plasma physics and fluid dynamics

In this paper, we mainly study the resonant interactions of lump chains of (2+1)-dimensional generalized Korteweg–de Vries (gKdV) equation, which can be used to describe the nonlinear wave phenomena in plasma physics, weakly dispersive media and fluid dynamics. We construct the lump chain solutions by adding some constraints to the soliton solutions of the gKdV equation. Then through the asymptotic analysis, the analytical solution of each branch of the lump chains after interaction is obtained. Through the phase shift analysis of the analytical solution, we get the condition of resonance, and then the resonant interactions of the two- and three-lump chains are analyzed in detail. In particular, we explore two cases including the cross-resonant interaction and parallel-resonant interaction of the lump chains. In addition, 2D and 3D images are used to describe the spatial evolution of resonant interactions. The results can further help us study the resonant interactions between the lump chains and other nonlinear waves.

An analysis of wave dispersion in an anisotropic medium through peridynamic theory

An analysis of wave dispersion in an anisotropic medium through peridynamic theory

Symmetry-protected lossless modes in dispersive time-varying media

We give an exact application of a recently developed, operator-based theory of wave propagation in dispersive, time-varying media. Using this theory, we find that the usual symmetry of complex conjugation plus changing the sign of the frequency, required for real-valued fields, implies that the allowed propagation constants in the medium are either real valued or come in conjugate pairs. The real-valued wave numbers are only present in time-varying media, implying that time variation leads to modes that are free from dissipation, even in a lossy medium. Moreover, these symmetry-unbroken waves lack a defined propagation direction. This can lead to a divergent transmission coefficient when waves are incident onto a finite, time-varying slab. The techniques used in this paper present a route toward further analytic applications of this operator formalism. Published by the American Physical Society 2025

Non-dispersive short pulses supported by quasiperiodic spatiotemporal gratings

It is shown that a quasiperiodic spatiotemporal grating formed in a dispersive medium enables the propagation of linear localized pulses of the probe field without dispersive spreading. Increasing the amplitude or modulation depth of the grating allows for the accommodation of a larger number of probe pulses. In the case of a formally infinite grating, these pulses propagate without distortion at the velocity of the spatiotemporal lattice. When the grating has finite spatial and temporal extents, a wide Gaussian probe pulse evolves into a sequence of non-interacting localized pulses that propagate over long distances with significantly reduced dispersion.

Numerical Study of Non-Schell Model Pulses in Nonlinear Dispersive Media with the Monte Carlo-Based Pseudo-Mode Superposition Method

Recently, we introduced random complex and phase screen methods as powerful tools for numerically investigating the evolution of partially coherent pulses (PCPs) in nonlinear dispersive media. However, these methods are restricted to the Schell model type. Non-Schell model light has attracted growing attention in recent years for its distinctive characteristics, such as self-focusing, self-shifting, and non-diffraction properties as well as its critical applications in areas such as particle trapping and information encryption. In this study, we incorporate the Monte Carlo method into the pseudo-mode superposition method to derive the random electric field of any PCPs, including non-Schell model pulses (nSMPs). By solving the nonlinear Schrödinger equations through numerical simulations, we systematically explore the propagation dynamics of nSMPs in nonlinear dispersive media. By leveraging the nonlinearity and optical coherence, this approach allows for effective control over the focal length, peak power, and full width at half the maximum of the pulses. We believe this method offers valuable insights into the behavior of coherence-related phenomena in nonlinear dispersive media, applicable to both temporal and spatial domains.

О голоморфных и кусочно-голоморфных сигналах

The properties of holomorphic and piecewise holomorphic signals during propagation in a dispersing medium are compared. It is shown that the status of the signal (holomorphic or piecewise holomorphic) cannot be changed by any physically realizable (that is, not violating the principle of causality) filter. It is shown that the properties of holomorphic and piecewise holomorphic signals are not only different, but usually directly opposite. For example, piecewise holomorphic signals (unlike holomorphic ones) necessarily have precursors, fade out in an absorbing medium according to a hyperbolic (rather than exponential) law, have an anthropogenic (rather than natural) origin, and transfer information (unlike holomorphic ones). Holomorphic signals (unlike piecewise holomorphic ones) are capable of propagating as a whole with a group velocity (and any one – sublight, superluminal, negative and complex).

Deep eutectic solvent-based ionogel: Innovative potential as a promising chromatographic separation material.

Deep eutectic solvent-based ionogel: Innovative potential as a promising chromatographic separation material.

Comparative Study of Colloidal and Rheological Behaviors of Mixed Palygorskite–Montmorillonite Clays in Freshwater and Seawater

This study systematically investigates the colloidal stability, rheological properties, and filtration behavior of palygorskite–montmorillonite mixed clays in both freshwater and seawater systems. By varying the mass content and dispersion medium (freshwater/seawater), we analyze the colloidal stability, zeta potential, flow curves, viscosity, shear-thinning behavior, thixotropy, and fluid loss of the dispersions. The results show that palygorskite exhibits good rheological performance in both freshwater and seawater, while montmorillonite performs better in freshwater but suffers a significant decline in seawater. However, palygorskite demonstrates high fluid loss, which is unfavorable for drilling fluid function. Mixed clays can mitigate the limitations of individual clays to some extent, but the specific performance depends on the clay mineral content and dispersion medium. In freshwater, a small amount of montmorillonite improves the viscosity and shear-thinning behavior of the dispersion, with optimal montmorillonite contents of 22% and 38%, respectively. The thixotropy and fluid loss reduction in the mixed clays are positively correlated with montmorillonite content. In seawater, the rheological performance inversely correlates with Mt content due to montmorillonite’s high sensitivity to electrolytes. The addition of Pal enhances the colloidal stability and rheological properties of the mixed clays in seawater. This work provides theoretical insights into the behavior of mixed clays in different media, offering valuable guidance for the design of seawater-based drilling fluids.

Development of the composition of a dermatological product in the form of a cream with extracts of the aerial part of lespedeza bicolor

The aim of the work: Justification of the composition of emulsion cream with extracts of Lespedeza bicolor. Materials and methods: In the development of the emulsion base of the cream, corn oil (Ukraine), propylene glycol (Germany), purified water, emulsifiers: xyliance (France), prolipid 141 (USA) and lamecrem (France) were used. The composition of the emulsion base included oil and liquid alcohol extract of the above-ground part of Lespedeza bicolor, which were obtained from the above-ground part of Lespedeza bicolor, harvested in the Botanical Garden of the Ivan Franko National University of Lviv (Lviv, Ukraine) in the flowering phase. The studies used physicochemical (pH value, identification and quantitative content of BAS), pharmacotechnological (thermo- and colloidal stability, structural-mechanical properties and disperse analysis) research methods. The anti-inflammatory activity of the experimental samples was studied on a burn wound model in outbred sexually mature male rats. The following medicines were used as comparison drugs: Panthenol ointment, “Hemofarm”, AD, Serbia, series 138CLA and Calendula ointment, LLC “Pavlova Pharmacy”, Ukraine, series 23.0823. Results. Experimental studies of the organoleptic, physicochemical and structural-mechanical properties of samples of emulsion bases showed their dependence on the concentration of the oil phase, the composition and concentration of complex emulsifiers xyliance, prolipid 141 and lamecrem. It was established that the emulsion base of the cream, which contains 15 % corn oil, 7 % of the complex emulsifier xyliance, 5 % propylene glycol and water purified to 100, has satisfactory structural-mechanical properties, the necessary dispersion and homogeneous distribution of particles of the oil phase in the aqueous dispersion medium, withstands the test for thermal and colloidal stability and can be used to develop a dermatological cream with Lespedeza extracts. It was shown that the introduction of extracts into the composition of the developed base does not affect the stability, structural-mechanical properties of the base and the content of BAS. Studies of the anti-inflammatory activity of a cream with a complex of biologically active compounds of the oily and alcoholic extracts of the terrestrial part of Lespedeza bicolor on a burn wound model showed a reduction in signs of inflammation without signs of the joining of an infectious process in laboratory animals with wound healing on the 26th day of the study. Conclusions. The composition of the cream with oil and alcohol extract of Lespedeza, which, due to the BAS complex, has a wider spectrum of pharmacological activity, has been experimentally substantiated. The composition of the emulsion base of the cream with corn oil, xyliance emulsifier, propylene glycol and purified water has been developed. It has been shown that the introduction of extracts into the composition of the developed base does not affect its pharmacotechnological properties, and the quantitative content of biologically active compounds in the cream corresponds to their content in the extracts in terms of the concentration of extracts in SDF, which is a confirmation of the compatibility of BAS with excipients. It has been established that the cream containing the BAS complex of Lespedeza bicolor in terms of anti-inflammatory activity is at the level of the comparison preparations Panthenol ointment and Calendula ointment

Research on the development of the composition of complex action dental films with calcium hydroxyapatite

The aim. Development of the composition of dental films for remineralization, treatment and prevention of dental hyperesthesia, prevention of the formation of microbial biofilms, elimination of pathogenic microflora. Methods. Determination of crystallographic characteristics, uniformity of particle distribution and their ability to aggregation was carried out by microscopy, viscosity – by rotational viscometer, pH-potentiometrically. The tensile strength of the films, the ability to stretch and lengthen, the strength of the bioadhesive bond were investigated by a texture analyzer, the thickness of the films – by calipers. Antimicrobial activity was determined by the disk-diffusion method and by the effectiveness of antimicrobial preservatives. Results. The choice of CHA concentration (10 %) was based on the analysis of literature sources. Structural-mechanical and organoleptic studies established the feasibility of using a combined system with the inclusion of purified water, glycerin and macrogol 400. The study of sedimentation and aggregation stability of the samples showed a uniform distribution of particles in samples from PVA, HEC, HPC. Films from Sodium Alginate, PVP, Na-CMC and HPMC were excluded from the work due to unsatisfactory properties. Structural-mechanical and physico-chemical properties allowed us to choose 5 % PVA as the film former, and 4 % glycerin as the plasticizer. The concentrations of API (metronidazole and chlorhexidine) were selected based on antimicrobial activity and preservative effect. Conclusions. As APIs, CHA – a remineralizing, anti-caries agent, metronidazole and chlorhexidine – antimicrobial components were selected. The introduction of CHA is rational in a complex dispersion medium, metronidazole as a suspension with glycerin, chlorhexidine as a 20 % solution. The composition of the film base was substantiated. The concentrations of metronidazole and chlorhexidine bigluconate were determined. The developed drug met the specifications of the MQC

New Experimental Approach for the Proper Consideration of Stagnant and Diffuse Layer Conductivity in the Zeta Potential Determination.

Accurate determination of the zeta potential in colloidal dispersions often requires consideration of the relaxation effect, which is associated with the polarization of the electrical double layer and the surface conductivity. In this study, we pursue a new approach that combines conductivity measurements of the dispersion and dispersion medium with the electroacoustic and electrophoretic zeta potential determination. The conductivity data are analyzed with the Maxwell-Wagner-O'Konski theory, providing the Dukhin number. Zeta potentials of highly concentrated polymer dispersions were determined using the colloid vibration current (CVI) method and compared with those obtained by electrophoretic light scattering (ELS) in diluted dispersions. In both cases, the relaxation effect was now taken into account on the basis of the experimentally determined Dukhin number. The evaluation of the Dukhin numbers revealed significant surface conductivity for all investigated polymer dispersions. In addition, it was often found that not only the diffuse layer but also the stagnant layer contributes considerably to the surface conductivity. Proper consideration of both effects is essential for the reliable determination of the zeta potential, as otherwise inconsistencies can be observed in the evaluated data. Moreover, we have validated for the first time that the advanced CVI theory takes the effect of surface conductivity properly into account for a wide range of particle volume fractions. These values agree well with those obtained by the ELS method using the Dukhin-Semenikhin theory or a modified theory of Ohshima, Healy, and White. This study thus shows that the Dukhin number can serve as a key parameter to reliably connect conductivity and electrophoretic and electroacoustic experiments.

Kerr self-focusing of few-cycle terahertz pulses in dispersive media

Abstract Kerr self-focusing is one of the most common and fundamental nonlinear phenomena during high-power light pulses propagating through transparent media. It occurs usually when the pulse peak power exceeds a certain critical power and the Kerr nonlinearity overcomes the diffraction effect. In this paper, the nonlinear propagation of terahertz (THz) pulses in dispersive media is studied via numerical simulations. It is found that, for few-cycle THz pulses, the Kerr self-focusing is suppressed dramatically, and a substantially higher THz intensity than that defined by the well-known formula of self-focusing critical power is required to enable an observable spatial self-focusing behaviour. By theoretical modelling and numerically analysing the time-domain evolution of broadband THz pulses in media, the underlying physical cause is attributed to the dominance of the significant dispersion effect over the diffraction effect, resulting in that the Kerr nonlinearity competes with dispersion instead of diffraction. A modified analytical expression for the dispersion-mediated self-focusing critical intensity is derived and shows good agreement with simulation results. The influences of THz pulse and medium dispersion parameters on the THz propagation dynamics are systematically studied such as the THz cycle number, intensity, initial chirp and absolute phase as well as the medium group velocity dispersion, high-order dispersion and their sign. These results have important implications for the study of strong-field THz wave—matter interactions and THz nonlinear optics.

Linier Perturbation Method Analytic Shear Wave Propagation In A Dispersive Medium

This research was based on showing how the relationship of the perturbation method to the wave function entering the dispersive medium area. Disperse medium is a medium where when the wave enters the area, it experiences changes in wave shape and wave energy. The purpose of this study is to show how the perturbation method can be reduced to a term that is still linear with the assumption that the next term is very small so that the wave term is still linear to the wave change. This research is qualitative research. The place of this research is at the TD Pardede Institute of Science and Technology. From the analysis in this study, it was found that the wave experienced a decreasing intensity towards the depth of the dispersive medium with the assumption that the attenuation coefficient ( ) was still continuous along the depth of the material passed by the wave. In the case of seismic waves when the wave moves through the medium, its intensity decreases with distance. The presence of disturbances in the layer passed by the wave causes the shift of the material to experience a disturbance characteristic where the wave amplitude is getting smaller. This is because the absorption of wave energy by the particles of the dispersive medium continues to experience attenuation.

Oceanic water waves via double and single convex-concave solitons in the generalized Whitham-Broer-Kaup-Boussinesq-Kupershmidt equations with a novel truncated MM-derivative

Abstract A classical system of generalized Whitham-Broer-Kaup-Boussinesq-Kupershmidt equations (gWBKBKEs), describing long shallow-water waves in a dispersive medium, has been extensively studied. This paper introduces a novel fractional derivative, the truncated modified Mittag-Leffler function derivative (TMMD), and investigates its impact on behaviors of solutions of gWBKBKEs. Using the unified method (UM), exact solutions for single-wave systems are derived, as the equations are integrable in such cases. However, for two-wave systems, where integrability is lost, only approximate solutions are achievable. The UM ensures that the maximum error is controlled through optimal parameter selection in the remainder terms The horizontal velocity and wave height deviations from the equilibrium are illustrated. Novel waves structures are revealed including convex-cavity, concave-cavity-solitary waves and curly wave-train. Also, a formation of waves in interactions of the basin and solitons is found. These results are explored via the derived solutions. Stability analysis asserts that the initial state becomes unstable when the initial horizontal velocity exceeds a critical threshold linked to the deviation height. Furthermore, the effect of the fractional parameter in the TMMD is examined, showing minimal impact on the intensity of horizontal velocity and wave height deviations.

Line shape of soft photon radiation generated at zero angle in an undulator with a dispersive medium

Line shape of soft photon radiation generated at zero angle in an undulator with a dispersive medium

Topology of Bloch impedance: traveling waves, dispersive media, and electromagnetic energy

Abstract The bulk-boundary correspondence (b-bc) principle, which relates interface modes between two periodic structures to topological invariants of the respective Bloch bands, is widely accepted in electrodynamics. However, this acceptance stems largely from condensed matter (CM) theories. It is desirable to establish direct connections between the topological principles and Maxwell electrodynamics, rather than relying on CM results. Such connections have in recent years been found in the case of standing evanescent waves in periodic dielectric media. This paper extends these analyses to waves propagating along an interface between two periodic structures, possibly with frequency-dependent dielectric permittivities. The paper shows that the b-bc principle continues to hold for any physically realizable structures, in which the density of electromagnetic energy must be positive. The paper rigorously proves that in this physically valid case impedance of traveling interface modes within any given bandgap decreases monotonically as a function of frequency.

Explicit Synchronized Solitary Waves for Some Models for the Interaction of Long and Short Waves in Dispersive Media

Abstract A system coupling the cubic, nonlinear Schrodinger equation (NLS) and the Korteweg–de Vries equation (KdV) commonly known as the NLS–KdV system was previously analysed to be inconsistently derived and a few alternative systems were proposed as more suitable models for describing the interaction of long and short waves in dispersive media (Deconinck et al. in J Phys A: Math Theor 49:415501, 2016. https://doi.org/10.1088/1751-8113/49/41/415501; Nguyen and Liu in Water Waves 2:327–359, 2020. https://doi.org/10.1007/s42286-020-00038-6; Commun Math Sci 21(3):641–669, 2023. https://doi.org/10.4310/CMS.2023.v21.n3.a3). In this manuscript, these alternative systems are shown to possess synchronized solitary waves via the method of constrained minimization, as well as by direct computation of the associated systems of ODEs. These synchronized solitary waves have the hyperbolic $$\textrm{sech}^2$$ sech 2 -profile typical of dispersive equations.

Analysis of particle settlement characteristics in a one-dimensional deterministic model

In this paper, we investigate how particles settle in a one-dimensional deterministic model. We leverage a model for deterministic Brownian motion and introduce boundary conditions to simulate particle settling. By adjusting parameters in the Jerk equation, we explore how different diffusion, and the size of the settling space affect the particles’ behavior. We analyze how these parameters influence the settling time and its relationship to the dispersion medium. Additionally, we examine statistical properties as follows: the average settling time, the probability distributions for mean displacement, and how the probability distribution of settling times changes with the size of the space.

Influence of air dispersion on the stability of laser pulses

Abstract The dynamics of pulses propagating in nonlinear dispersive medium are considered. The analysis is based on a theoretical model without the dispersion series expansion that is applicable to the complex dispersion response of air containing many components. A soliton-like solution and the conditions of its stability are obtained. It is shown that there is a limit to the duration of the signal under which it will be stable.