Two-dimensional Media Research Articles

Casimir force tuning in 2D materials: effect of rotation in phosphorene

We theoretically examine the Casimir force with Lifshitz theory for two-dimensional media: graphene and phosphorene. We calculate the Casimir force for three different configurations: (a) phosphorene-graphene, (b) phosphorene-phosphorene (with rotation), and (c) a system composed of gold and a two-dimensional material (graphene or phosphorene). According to our calculations, we have determined that systems consisting solely of two-dimensional media can reduce the magnitude of the Casimir force by half or more, in comparison to systems composed of two-dimensional material and gold. The results show that in phosphorene configurations, high frequencies play a dominant role in contributing to the Casimir force, allowing greater force magnitudes for low interlayer distances compared to systems composed of gold or graphene. Our calculations also show that, as a result of the anisotropy of the phosphorene layers, it is possible to design a mechanical modulator with only two phosphorene layers by considering a relative rotation between them by an angle θ. In this regard, the anisotropy of phosphorene and the modulation of the separation between the phosphorene layers make it possible to tune the amplitude of Casimir force. The proposed configurations could lead to the development of nanotechnology applications incorporating 2D materials into their structures.

The effect of narratives in United Nations Virtual Reality

Viewed as an empathy machine, Virtual Reality (VR) film has been utilized by many humanitarian organizations. to augment individuals’ comprehension of humanitarian issues and evoke empathetic responses. Despite extensive analysis on the impact of virtual reality in eliciting empathy and its narrative techniques, there exists a research gap regarding the specific attributes of UNVR films. This paper critically examines the positive effects, unresolved challenges, and ethical concerns of UNVR films, particularly through the lens of various narrative techniques, including their documentary realism, montage, external authorship, and extra-diegetic voice-over. This paper calls attention to how UNVR films, despite conveying the same content and expressing the same ideas, achieve better effects than one-dimensional or two-dimensional media, enhancing the audience’s comprehensions of suffering groups such as refugees and eliciting empathy, while also pointing out the challenges that UNVR still faces. The paper also analyzes the fundamental deficiencies of UNVR in terms of embodiment and eliciting empathy. It will conclude with suggestions for future research on how to utilize narrative techniques, based on unique features of VR, to enhance the role of UNVR in addressing humanitarian issues.

T-matrix of piezoelectric shunt inclusions on a thin plate

Developing piezoelectric-based plate-like metamaterials necessitates an effective modeling method to elucidate the omnidirectional wave properties of piezoelectric coupled inclusions on a thin plate. The commonly used methods, such as the transfer-matrix method and finite element method, are inadequate for analyzing the transmission and reflection of omnidirectional waves in a two-dimensional elastic medium. Unlike the existing methods, the multiple scattering method employs Bessel functions as the displacement-basis methods which can accurately describe the propagation and scattering characteristics of omnidirectional waves. This paper develops a novel T-matrix formulation to support the multiple scattering method, representing the input-output relationship between incident and reflected waves from a piezoelectric shunt inclusion on a host thin plate. The piezoelectric shunt inclusion comprises a varying-thickness substrate bonded with piezoelectric shunting patches. The T-matrix of the piezoelectric shunt inclusion is formulated by integrating the wave-based method with Rayleigh-Ritz method. The derived T-matrix is then used to semi-analytically analyze the far-field scattering and reflection properties of a single inclusion. Numerical results capture the scattering properties resulting from trapped mode resonances of the piezoelectric shunt inclusion. Additionally, the capability of the piezoelectric shunt damping to design and tune multiple critical coupling conditions for axisymmetric modes of thin plates is parametrically investigated by varying the values of inductors and resistors.

Orbital angular momentum and rotational properties of off-axis vortex beams in two-dimensional media with anisotropic nonlocal nonlinearity.

By introducing anisotropy into nonlinear propagations, off-axis vortex beams exhibit significantly different characteristics compared to the isotropic case. The orbital angular momentum (OAM) is non-conservative and can periodically change between positive and negative values. Accordingly, the rotation of phase singularity can transit between clockwise and counterclockwise directions. Furthermore, the phase singularity can move to infinity when the OAM approaches zero. By using the Ehrenfest theorem, the motion of the beam center is obtained. Its trajectory can be circular and parabolic or follow other complex shapes, depending closely on the anisotropy of the nonlinearity. The rotational velocity of the beam center can be modulated by the nonlinearity anisotropy and can far exceed the initial value during its propagation. These results may find potential applications in beam shaping and optical manipulation.

Expanding Applications and Artistic Principles of Motion Graphics in Digital Media

Motion graphics, in contrast to traditional two-dimensional media, provide the user with an experience that is more intuitive, dynamic, multi-dimensional, rhythmic and narrative. This study examines the principles and evolution of motion graphics in digital media, including television commercials, websites, applications, interactive installations, and graphic design. By analysing their dynamic, rhythmic and narrative characteristics, this paper outlines the principles of art construction from the perspectives of time, space, communication and synthesis. It also explores the artistic expression of motion graphics through three main avenues: enhancing information presentation, expanding graphic creativity, and integrating multiple forms. To illustrate how these principles enhance information presentation, expand creative boundaries and integrate multiple forms, an in-depth literature review and a series of case studies are conducted. Conclusions focus on providing guiding principles for using motion graphics in modern digital environments.

The impact of diffusiophoresis on hydrodynamic dispersion and filtration in porous media

It is known that the dispersion of colloidal particles in porous media is determined by medium structure, pore-scale flow variability and diffusion. However, much less is known about how diffusiophoresis, that is, the motion of colloidal particles along salt gradients, impacts large-scale particle dispersion in porous media. To shed light on this question, we perform detailed pore-scale simulations of fluid flow, solute transport and diffusiophoretic particle transport in a two-dimensional hyper-uniform porous medium. Particles and solute are initially uniformly distributed throughout the medium. The medium is flushed at constant flow rate, and particle breakthrough curves are recorded at the outlet to assess the macroscopic effects of diffusiophoresis. Particle breakthrough curves show non-Fickian behaviour manifested by strong tailing that is controlled by the diffusiophoretic mobility. Although diffusiophoresis is a short-time, microscopic phenomenon owing to the fast attenuation of salt gradients, it governs macroscopic colloid dispersion through the partitioning of particles into transmitting and dead-end pores. We quantify these behaviours by an upscaled analytical model that describes both the retention and release of colloids in dead-end pores and the observed long-time tailings. Our results suggest that diffusiophoresis is an efficient tool to control particle dispersion and filtration through porous media.

Brush Seal Performance with Ideal Gas Working Fluid under Static Rotor Condition

The study investigated how variations in pressure ratio affect the leakage flow of a brush seal for both contact and clearance structures, in which the clearance is measured as the distance between the bristles tip and the rotor surface. This investigation utilized the Reynolds-Averaged-Navier–Stokes (RANS) equations alongside a two-dimensional axisymmetric anisotropic porous medium model. To verify the model’s accuracy and dependability, the obtained results were compared with previous numerical results and experimental observations, showing a satisfactory level of agreement. The results indicate that the predominant pressure drop occurs downstream of the bristle pack with the clearance model exhibiting a higher leakage rate compared to the contact model. Leakage increases proportionally with the pressure ratio, while axial velocity gradually rises and radial velocity experiences a significant increase. In conclusion, the leakage in the brush seal contact structure is significantly lower than in the clearance structure, resulting in the best performance.

The geometry of induced currents in two-dimensional media

We present a framework that allows us to clearly identify the geometric features underlying the phenomenon of superconductivity in two-dimensional materials. In particular, we show that any such medium whose response to an externally applied electromagnetic field is a geodesically flowing induced current, must be a superconductor. In this manner, we conclude that the underlying geometry of this type of media is that of a Lorentzian contact manifold. Moreover, we show that the macroscopic hallmark of their superconducting state is a purely topological condition equivalent to the geodesic nature of the induced current: the non-vanishing of its helicity.

A Legendre Spectral-Element Method to Incorporate Topography for 2.5D Direct-Current-Resistivity Forward Modeling

An effective and accurate solver for the direct-current-resistivity forward-modeling problem has become a cutting-edge research topic. However, computational limitations arise due to the substantial amount of data involved, hindering the widespread use of three-dimensional forward modeling, which is otherwise considered the most effective approach for identifying geo-electrical anomalies. An efficient compromise, or potentially an alternative, is found in two-and-a-half-dimensional (2.5D) modeling, which employs a three-dimensional current source within a two-dimensional subsurface medium. Consequently, a Legendre spectral-element algorithm is developed specifically for 2.5D direct-current-resistivity forward modeling, taking into account the presence of topography. This numerical algorithm can combine the complex geometric flexibility of the finite-element method with the high precision of the spectral method. To solve the wavenumber-domain electrical potential variational problem, which is converted into the two-dimensional Helmholtz equation with mixed boundary conditions, the Gauss–Lobatto–Legendre (GLL) quadrature is employed in all discrete quadrilateral spectral elements, ensuring identical Legendre polynomial interpolation and quadrature points. The Legendre spectral-element method is applied to solve a two-dimensional Helmholtz equation and a resistivity half-space model. Numerical experiments demonstrate that the proposed approach yields highly accurate numerical results, even with a coarse mesh. Additionally, the Legendre spectral-element algorithm is employed to simulate the apparent resistivity distortions caused by surface topographical variations in the direct-current resistivity Wenner-alpha array. These numerical results affirm the substantial impact of topographical variations on the apparent resistivity data obtained in the field. Consequently, when interpreting field data, it is crucial to consider topographic effects to the extent they can be simulated. Moreover, our numerical method can be extended and implemented for a more accurate computation of three-dimensional direct-current-resistivity forward modeling.

Penerapan Motif Ukiran Minangkabau Sebagai Jam Hias

The aim of making this work is to visualize the meaning contained in Minangkabau motifs in carvings using surian wood as a three-dimensional work with the theme being the lessons we take from everyday life. The method used in making this work goes through several stages, namely: (1). Preparation Stages, (2). Elaboration Stages, (3). Synthesis Stages, (4). Concept Realization Stages, (5). Finishing stages The results of the works that have been visualized in two-dimensional media have been developed resulting in the titles kaluak Paki, "bungo panca matoari", "Carano Kanso", "pucuak rabuang", "kambang manih", "Bungo Teratai", "siriah gadang."

Research on recovering scattering obstacles in inhomogeneous medium based on Bayesian method

ABSTRACT In this paper, the problem of acoustic wave scattering by obstacles in the two-dimensional inhomogeneous medium is considered. When the refractive index is a binary function, a hybrid method for reconstructing multiple impenetrable obstacles is proposed. The obstacle number is predicted based on the measured far-field data by using the neural network method. And then, it is used as the prior information of Bayesian method, the shape and position parameters of multiple obstacles are reconstructed using Markov chain Monte Carlo algorithm. The results of numerical experiments show that this method can effectively reconstruct the number, shape and position of obstacles in the inhomogeneous medium.

Active intruder motion in a two-dimensional granular medium

We studied an active intruder traversing a two-dimensional granular medium. First, we conducted experiments to analyze the motion of the active intruder within a bed of soft particles distributed throughout a horizontal container. Our observations revealed that the intruder preferentially moved along regions characterized by higher disorder. As a consequence of its motion, and as the intruder repeatedly traversed specific regions, the structure in the vicinity of the path, but also in more distant regions, gradually became more ordered. Additionally, the motion of the intruder tended to be localized in closed paths, with this effect becoming more pronounced at higher particle concentrations. Secondly, we analyzed the behavior of the active intruder within a slightly tilted container and under vibration and shearing conditions, which served to fluidize the granular bed. Our findings indicated that the trajectory of the intruder tended to intersect regions of the granular medium with lower structural order. The overall order and fluidization degrees were found to be the primary influences on the intruder’s penetration length. We used the sixth-bond-orientational order parameter to characterize the local structural aspects of the medium and the mean squared displacement to describe the dynamics of both the intruder and the medium. We conducted an experimental analysis of the ordering of the medium and motion of the intruder using network contact forces in a similar system based on soft gelatin particles. The results of this experimental analysis are consistent with the general results, showing that media with an ordered configuration exhibit more resistance than disordered media.

Numerical Simulations of Viscous Fingering in Fractured Porous Media

AbstractThe effect of heterogeneity induced by highly permeable fracture networks on viscous miscible fingering in porous media is examined using high-resolution numerical simulations. We consider the planar injection of a less viscous fluid into a two-dimensional fractured porous medium that is saturated with a more viscous fluid. This problem contains two sets of fundamentally different preferential flow regimes; the first is caused by the viscous fingering, and the second is due to the permeability contrasts between the fractures and the rock matrix. We study the transition from the regime where the flow is dominated by the viscous instabilities, to the regime where the heterogeneity induced by the fractures define the flow paths. Our findings reveal that even minor permeability differences between the rock matrix and fractures significantly influence the behavior of viscous fingering. The interplay between the viscosity contrast and permeability contrast leads to the preferential channeling of the less viscous fluid through the fractures. Consequently, this channeling process stabilizes the displacement front within the rock matrix, ultimately suppressing the occurrence of viscous fingering, particularly for higher permeability contrasts. We explore three fracture geometries: two structured and one random configuration and identify a complex interaction between these geometries and the development of unstable flow. While we find that the most important factor determining the effect of the fracture network is the ratio of fluid volume flowing through the fractures and the rock matrix, the exact point for the cross-over regime is dependent on the geometry of the fracture network.

Variational Algorithms of Deep Kinematic Migration in Two-Dimensional Media with a Horizontal Velocity Gradient

Variational Algorithms of Deep Kinematic Migration in Two-Dimensional Media with a Horizontal Velocity Gradient

Impact of cationic surfactant-coated hydrophilic nanoparticles on polymeric solution performance in chemical enhanced oil recovery (CEOR) from a two-dimensional porous medium

This study aims to investigate the mechanisms underlying enhanced oil recovery (EOR) through chemical injection and explore the key parameters influencing these mechanisms in a two-dimensional porous medium. Distilled water, polyacrylamide (PAM), α-Al2O3 nanoparticles, and cetyltrimethylammonium bromide (CTAB) surfactant were employed for this purpose. The effects of interfacial tension (IFT), viscosity, and zeta potential measurement were also examined. The results revealed that the injection of PAM polymer increased the viscosity of the displacing fluid, and enhanced the sweep efficiency. This resulted in a 35 % increase in the oil recovery factor compared to the water injection alone. Furthermore, the introduction of alumina (α-Al2O3) nanoparticles altered the wettability and stabilized the emulsion, leading to a further increase in the oil recovery factor. In the optimal state, the oil recovery factor reached 63.2 %. Moreover, the study of various concentrations of polymer and nanoparticles illustrated that low concentrations of polymer and high concentrations of nanoparticles in the base fluid resulted in higher oil recovery factors. Furthermore, adding CTAB surfactant ended a significant reduction in IFT, with a decrease from 45.03 to 10.33 mN/m. This reduction resulted in the highest oil recovery factor of 69 %. Consequently, the highest oil recovery factor was achieved using PAM polymer at a concentration of 500 ppm, α-Al2O3 nanoparticles at a concentration of 0.1 wt%, and CTAB surfactant at a critical micelle concentration of 1 mM in the base fluid (pure water), with a constant injection flowrate of 0.1 ml/min.

Influence of thermal load on a rotating thermoelastic medium with diffusion and double porosity

In the present work, we have studied the thermodynamical interactions in a two-dimensional thermoelastic medium with diffusion, rotation and double porosity in the context of Green–Lindsay theory. A thermal load is applied at the outer free surface of the medium. The normal mode technique is employed to derive the analytic expressions of the field quantities such as stresses, displacement components, temperature field and mass concentration. Numerical computations are performed with the help of MATLAB software for a specific material for illustrating the results. To the author’s best knowledge, no attempt has been made to investigate the therodynamical interactions in a rotating double porous thermoelastic medium with diffusion under the influence of a thermal load. Comparisons of the physical quantities are shown in figures to study the effects of time, double porosity, rotation, thermal load and diffusion. Some particular cases of interest have also been inferred from the present problem. The theoretical and numerical computations are found to be in close agreement.

Backscattering-free edge states below all bands in two-dimensional auxetic media

Unidirectional and backscattering-free propagation of sound waves is of fundamental interest in physics and highly sought-after in engineering. Current strategies utilize topologically protected chiral edge modes in bandgaps or complex mechanisms involving active constituents or nonlinearity. Here, we propose a new class of passive, linear, one-way edge states based on spin-momentum locking of Rayleigh waves in two-dimensional media in the limit of vanishing bulk modulus, which provides 100% unidirectional and backscattering-free edge propagation immune to any edge roughness at a broad range of frequencies instead of residing in gaps between bulk bands. We further show that such modes are characterized by a new topological winding number that is analogous to discrete angular momentum eigenvalues in quantum mechanics. These passive and backscattering-free edge waves have the potential to enable a new class of phononic devices in the form of lattices or continua that work in previously inaccessible frequency ranges.

Temporal evolution of sound pulse in shallow water under conditions of horizontal refraction. Vertical modes and space-time horizontal rays

As is known, to describe horizontal refraction in a shallow water waveguide, the “vertical modes and horizontal rays” approach (Burridge & Weinberg, 1974) is used, within which the two-dimensional eikonal equation for the modal amplitude includes the refractive index determined by the eigenvalues depending on the horizontal coordinates (x,y) and frequency (f). In other words, we have an effective two-dimensional inhomogeneous dispersive medium, to describe the propagation of signals in which, the authors propose to use the so-called space-time rays (Rytov, 1940, Connor & Felsen, 1974, Hillion, 1993) applied for the horizontal plane (STHR). The set of STHRs in a given situation is constructed for each mode. Within the framework of this approach, it is possible to obtain the evolution of the pulses of each mode from the solution of the nonstationary eikonal equation in the horizontal plane or from the corresponding Hamilton-Jacobi equations, obtained using non-local integral wave equation. Examples of constructing STHR in some typical situations (in particular in a wedge) are considered, some specific effects during signal propagation are considered, in particular, the so-called the pulse front tilt, previously discovered in laser optics (Bor & Rasz, 1985). Work was supported by ISF, grant 946/20.

Bio-convection of ternary magnetized nanoparticles thermal conductivity in chemical reaction and activation energy flow with Darcy Forchheimer permeable across a double porous medium

This research focuses on investigating the impact of magnetized nanoparticles’ heat and mass transfer process two-dimensional (2D) porous medium ternary hybrid Magnetohydrodynamics (MHD) ferrofluid flow through a two movable permeable porous surface, with a specific emphasis on the Darcy Forchheimer effect, activation energy, and chemical reaction parameters. Recently, motile microorganisms have become a significant area of interest in the study of heat and mass transfer. This study employs colored plots to analyze the optimum heat transfer over a double porous plate by altering different physical parameters. Using the shooting technique, the study provides numerical solutions to nonlinear systems of equations by transforming the partial differential equations (PDE) into ordinary differential equations (ODEs) via the dimensionless similarity transformation. Tables and graphs demonstrate how the governing parameters impact velocity, temperature, mass concentration profiles, and motile microorganisms, as well as physical quantities like skin friction coefficient, Nusselt number, Sherwood number, and motile number. Ternary hybrid ferrofluid exhibits a significantly improved heat transfer rate compared to both Ferro and hybrid ferrofluid. The convective flux of heat and mass transfer experiences a decrement with an escalation in the values of the activation energy (E) parameter. The presence of positive values for both the similarity variable (n) and Exothermic/Endothermic parameter (λ) leads to an enhancement in the flow of thermal transfer on both porous surfaces. This research will have far-reaching implications in various fields, including coolant technology in the manufacturing industry, heat dissipation in electronic modules, high-performance computing cooling facilities, the automotive sector, and space applications.

Algorithms of Deep Kinematic Migration in Two-Dimensional Media

Algorithms of Deep Kinematic Migration in Two-Dimensional Media