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In the present paper, we present a Cell-Centered Implicit Finite Difference (CCIFD) operator-based numerical scheme for the propagation of acoustic waves that is very effective, accurate, and small in size. This scheme requires fewer estimation points than the traditional central difference derivative operator. Any numerical simulation is significantly impacted by the precision of a numerical derivative. Long stencils can deliver excellent accuracy while also minimizing numerical anisotropy error. However, a long stencil requires a lot of computational resources, and as these derivatives get bigger, they could start to look physically unrealistic due to contributions from nodes located extremely far, wherein the derivative is local in nature. Furthermore, using such lengthy stencils at boundary nodes may result in errors. The present article investigates a cell-centered fourth order finite difference scheme to model acoustic wave propagation which utilizes a lesser number of nodes in comparison to the traditional Central Difference (CD) operator. However, in general the implicit derivative operator has high computational cost and therefore despite its significant advantages it is generally avoided to be implemented in applications. This serves as a motivation for the present paper to explore a technique called CCIFD that significantly decreases the computational expense by nearly fifty percent. Additionally, spectral characterization of the CCIFD derivative operator has been analyzed and discussed. Finally, the wave propagation has been numerically simulated in 2-dimensional homogeneous and Marmousi model using CCIFD scheme to validate the applicability and stability of the scheme. • Cell-Centered Implicit Finite Difference (CCIFD) scheme is discussed. • Spectral analysis is performed. • Error and anisotropy of CCIFD scheme is discussed. • CPU time for LU and LDMT decomposition is calculated and compared. • Numerical simulation is conducted in Homogeneous and Marmousi model. [ABSTRACT FROM AUTHOR]

In this paper, we study the vanishing dissipation limit of the 2D anisotropic Boussinesq equations with the Navier-slip boundary condition for velocity field and the fixed flux boundary condition for temperature in the upper half plane. By constructing boundary layer correctors to compensate for the discrepancies between dissipative equations and non-dissipative equations at the boundary, we prove that the solutions of the anisotropic Boussinesq equations converge to the solutions of the non-dissipative Boussinesq equations in L 2 -norm. Particularly, we find that the anisotropic dissipation coefficients only affect the rate of convergence, which is different from the phenomenon of the Dirichlet problem of the anisotropic Boussinesq equations in Wang & Xu (2021). [ABSTRACT FROM AUTHOR]

• Isotropic and anisotropic elastomers with tunable responses were investigated. • Magnetic fillings are homologous nanosheets with different magnetic properties. • The internal chain structures of the magnetic elastomers can be controlled. • Magnetic alignment makes composites behave better than isotropic elastomers. Magnetic elastomer composites with tunable magnetic responses from soft to hard magnetization have been synthesized. Co-Ti co-doped barium hexaferrite (BaCo x Ti x Fe 12–2x O 19) nanopowders were used as the filling and polydimethylsiloxane (PDMS) as the matrix. The effects of magnetic field-induced alignment of BaM magnetic particles in the matrix on the properties of the prepared composites have been investigated. For anisotropic magnetic elastomers, the formed chain structure plays a positive role in the enhancement of the shear energy storage modulus of the elastomers. The enhanced energy storage modulus is increased by about 190 % compared with that of the isotropic magnetic elastomers. Due to the magnetic chain structure of the magnetic particles and its effect on the rubber molecular chain, the anisotropic magnetic elastomers can obtain higher magnetic deformation response capability in the direction of the parallel magnetic field. Their research lays a foundation for further designing tunable magnetic flexible sensors. [Display omitted] [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenides (TMDs) have received more interest for their potential role in future electronic and optoelectronic applications. Unlike other TMDs, Rhenium diselenide (ReSe _2 ) stands out for its distinctive anisotropic growth characteristics. These unique features arise from its low lattice symmetry and interlayer decoupling, this has sparked significant interest among researchers. Previous research has indicated the presence of various growth patterns, including dendritic formations and structures resembling flowers. In this study, we effectively produced ReSe _2 using the ‘Tilting Boat’ method to achieve growth on a 21 μ m scale. Through precise manipulation of the growth conditions, we successfully attained flakes of 21 μ m scale in comparison to prior findings. Moreover, we successfully produced a variety of shapes, including triangles, diamonds, and hexagons, on 1 × 1 cm ^2 Si/SiO _2 substrates. Furthermore, we achieved the successful production of a continuous ReSe _2 film on a 1 × 3 cm ^2 Al _2 O _3 substrate. We verified the distinct anisotropic properties of ReSe _2 via Raman Spectroscopy. Furthermore, we acquired three-dimensional visual representations of ReSe _2 flakes and continuous films via SEM measurements. By employing EDS data and analysing x-ray photoelectron spectroscopy spectra, we have established a compositional ratio of 1:2 for Re and Se, which aligns with the MX _2 structure. This confirmation indicates the successful synthesis of high-quality ReSe _2 flakes.

The primary goal of this article is to implement a dual reciprocity boundary element method (DRBEM) to analyze problems of rotating functionally graded anisotropic fiber-reinforced magneto-thermoelastic composites. To solve the governing equations in the half-space deformation model, an implicit–implicit scheme was utilized in conjunction with the DRBEM because of its advantages, such as dealing with more complex shapes of fiber-reinforced composites and not requiring the discretization of the internal domain. So, DRBEM has low RAM and CPU usage. As a result, it is adaptable and effective for dealing with complex fiber-reinforced composite problems. For various generalized magneto-thermoelasticity theories, transient temperature, displacements, and thermal stresses have been computed numerically. The numerical results are represented graphically to demonstrate the effects of functionally graded parameters and rotation on magnetic thermal stresses in the fiber direction. To validate the proposed method, the obtained results were compared to those obtained using the normal mode method, the finite difference method, and the finite element method. The outcomes of these three methods are extremely consistent.

Additive manufacturing technology is a method of manufacturing parts that are stacked layer by layer through the principle of discrete stacking, which is different from traditional subtractive manufacturing. It has been widely concerned due to its advantages of short process flow, high material-utilization rate, and highly flexible manufacturing. Additive metal manufacturing is the most important branch of additive manufacturing technology. Its forming parts have high complexity, showing excellent mechanical properties than ordinary castings. After more than 20 years of development, it has been widely used in aerospace, medical, energy, and other related fields. In the current mainstream metal material in the manufacturing process, the main use of high-energy beam-melting metal powders results in extremely high overcooling, whereas cold fine grains exhibit special precipitation and increase the mechanical properties of the material. However, there are still doubts about the corrosion performance of metal additive manufacturing parts in the service process. The mechanism of the corrosion effect of special microstructures and precipitation relative to materials in the service process is still unclear. Therefore, it is urgent to review the systematic research of the corrosion resistance of high-energy beam metal additive manufacturing parts. Corrosion resistance is also one of the key factors for metal additive manufacturing products to occupy a place in the market and should be paid attention to. Therefore, this article summarized the current research progress on the corrosion performance of metal additive manufacturing workpieces on three commonly used metal additive manufacturing technologies: laser melting, electron beam melting, and directional metal deposition. The residual stress, grain size, precipitated phase, and anisotropy affect the corrosion resistance behavior. The influence mechanism of the parameter optimization and heat-treatment process on the corrosion resistance of the material was analyzed. Finally, the prospects of improving the corrosion resistance of metal additive manufacturing products were discussed.

Abstract Background The nervous system is critical to the operation of various organs and systems, while novel methods with designable neural induction remain to exploit. Results Here, we present a conductive inverse opal film with anisotropic elliptical porous patterns for nerve orientation induction. The films are fabricated based on polystyrene (PS) inverse opal scaffolds with periodical elliptical porous structure and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) mixed polyacrylamide (PAAm) polymers fillers. It is demonstrated that the anisotropic elliptical surface topography allows the nerve cells to be induced into orientation connected with the stretching direction. Because of the anisotropic features of the film which can be stretched into different directions, nerve cells can be induced to grow in one or two directions, forming a neural network and promoting the connection of nerve cells. It is worth mentioning that the PEDOT:PSS-doped PAAm hydrogels endow the film with conductive properties, which makes the composite films be a suitable candidate for neurites growth and differentiation. Conclusions All these features of the conductive and anisotropic inverse opal films imply their great prospects in biomedical applications. Graphical Abstract

Abstract Inspired by the transport behavior of water and ions through the aligned channels in trees, we demonstrate a facile, scalable approach for constructing biomorphic cellular Si3N4 ceramic frameworks with well-aligned nanowhisker arrays on the surface of directionally aligned microchannel alignments. Through a facile Y(NO3)3 solution infiltration into wood-derived carbon preforms and subsequent heat treatment, we can faultlessly duplicate the anisotropic wood architectures into free-standing bulk porous Si3N4 ceramics. Firstly, α-Si3N4 microchannels were synthesized on the surface of CB-templates via carbothermal reduction nitridation (CRN). And then, homogeneous distributed Y−Si−O−N liquid phase on the walls of microchannel facilitated the anisotropic β-Si3N4 grain growth to form nanowhisker arrays. The dense aligned microchannels with low-tortuosity enable excellent load carrying capacity and thermal conduction through the entire materials. As a result, the porous Si3N4 ceramics exhibited an outstanding thermal conductivity (TC, k R ≈ 6.26 W·m−1·K−1), a superior flexural strength (σL ≈ 29.4 MPa), and a relative high anisotropic ratio of TC (k R/k L = 4.1). The orientation dependence of the microstructure-property relations may offer a promising perspective for the fabrication of multifunctional ceramics.

We examine how a square-grid microstructure affects the manner in which a Bingham fluid is convected in a sidewall-heated rectangular porous cavity. When the porous microstructure is isotropic, flow arises only when the Darcy–Rayleigh number is higher than a critical value, and this corresponds to when buoyancy forces are sufficient to overcome the yield threshold of the Bingham fluid. In such cases, the flow domain consists of a flowing region and stagnant regions within which there is no flow. Here, we consider a special case where the constituent pores form a square grid pattern. First, we use a network model to write down the appropriate macroscopic momentum equations as a Darcy–Bingham law for this microstructure. Then detailed computations are used to determine strongly nonlinear states. It is found that the flow splits naturally into four different regions: (i) full flow, (ii) no-flow, (iii) flow solely in the horizontal direction and (iv) flow solely in the vertical direction. The variations in the rate of heat transfer and the strength of the flow with the three governing parameters, the Darcy–Rayleigh number, Ra, the Rees–Bingham number, Rb, and the aspect ratio, A, are obtained.

Differences in yarn and fabric structures lead to different thermal properties of the fabric, and even the thermal comfort of the textile. The heat transfer model of the cotton woven fabric with different structural parameters was established by considering the effect of the anisotropic heat conduction of the fiber. The finite element method and experiment were combined to explore the influence of woven structure, yarn fineness, and yarn count of fabric on the heat properties of fabrics. A stronger correlation was found between experimental results and the anisotropic model than the isotropic model. Also, plain fabrics have the strongest heat transfer properties followed by twill then satin fabric. As the yarn fineness increases from 18.5 to 35.5 tex, the heat transfer property of the samples decreases. When warp/weft density goes from 260 to 330 ends/10 cm, the heat transfer capacity of the samples shows an increasing trend. The fiber volume fraction of the fabric may be an important factor that can explain the above-mentioned relationship.

Several applications of a cylindrical waveguide filled with inhomogeneous materials have been demonstrated. Analytical solutions for modes, an inhomogeneous cylindrical waveguide, are available only for a few material parameters and those are also mostly approximations. We have obtained exact analytical solutions for cylindrical waveguides filled with different inhomogeneous and anisotropic material parameters. Different sets of material parameters are obtained using the geometric transformation method. The analytical and numerical modal field distributions, the value of cutoff frequencies and effective mode indices for different propagating modes are well matched to each other. The inhomogeneity can be used to miniaturize the radial dimensions of the waveguide. This is highly desirable for many applications like sensing, near-field coupling and magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

Typical targets in SAR observing scenes are characterized by anisotropy, which represents backscattering information changing with the observing angle. Anisotropic scattering can be used to study the structural characteristics of targets and the response differences between structures. In actual situations, due to flight conditions and other reasons, only partial observation information can be obtained, so it is important to use limited data to deduce remaining backscattering information for target analysis. In our article, the scattering deduction model based on matrix completion is established, including scattering characteristic analysis. The multi-aspect data is transferred from range and azimuth in conventional SAR image to pixel dimension and angle dimension for analysis. At the same time, the pixel similarity matrix is used as a feature in pixel dimension, and one-dimension back-amplitude scattering curve with angle is established as a feature matrix in angle dimension. In the process of modeling existing data, two corresponding decomposition matrices are generated with the help of collaborative filtering idea. Finally, a four-matrix combination for anisotropy deduction is formed. Ku-band multi-aspect data from autonomous experimental flights is used for algorithm. In the experiment, the scattering deduction of the remaining aspect sequence was carried out based on obtaining partial aspect sequence images, and the strong scattering regions of the target point and sub-aperture details were compared. The edge information and structure map of the target were reconstructed using scattering deduction results. [ABSTRACT FROM AUTHOR]

Understanding inhomogeneous and anisotropic fluid flows requires mathematical and computational tools that are tailored to such flows and distinct from methods used to understand the canonical problem of homogeneous and isotropic turbulence. We review some recent developments in the theory of inhomogeneous and anisotropic turbulence, placing special emphasis on several kinds of quasi-linear approximations and their corresponding statistical formulations. Aspects of quasi-linear theory that have received insufficient attention in the literature are discussed, and open questions are framed. [ABSTRACT FROM AUTHOR]

In this paper, the peripheral stability of a horseshoe-shaped tunnel in undrained clay with linearly increasing and directionally dependent strength is studied using the lower-bound theorem of plastic analysis coupled with finite-element formulation and second-order cone programming. The present analysis computes required supporting pressure for a tunnel constructed in isotropic/anisotropic normally consolidated (NC)/lightly overconsolidated (LOC) clay with linearly varying undrained strength across the depth, and isotropic/anisotropic heavily overconsolidated (HOC) clay whose undrained strength remains constant throughout the depth. Dimensionless stability charts have been produced for expressing the undrained stability of horseshoe tunnels in terms of anisotropic and heterogeneous parameters, tunnel cover depth, and normalized overburden pressure. The combined influence of these parameters on the peripheral stability of tunnels and associated failure mechanisms have also been examined and discussed. Further, a few analyses were done to examine the advantage of a horseshoe-shaped cross section in comparison with a circular cross section. [ABSTRACT FROM AUTHOR]

Anisotropic generalized Orlicz spaces have been investigated in many recent papers, but the basic assumptions are not as well understood as in the isotropic case. We study the greatest convex minorant of anisotropic Φ -functions and prove the equivalence of two widely used conditions in the theory of generalized Orlicz spaces, usually called (A1) and (M). This provides a more natural and easily verifiable condition for use in the theory of anisotropic generalized Orlicz spaces for results such as Jensen's inequality which we obtain as a corollary. [ABSTRACT FROM AUTHOR]

The anisotropic-diffusion convection equation of spatially variable coefficients which is relevant for functionally graded media is discussed in this paper to find numerical solutions by using a combined Laplace transform and boundary element method. The variable coefficients equation is transformed to a constant coefficients equation. The constant coefficients equation is then Laplace-transformed so that the time variable vanishes. The Laplace-transformed equation is consequently written in a pure boundary integral equation which involves a time-free fundamental solution. The boundary integral equation is therefore employed to find numerical solutions using a standard boundary element method. Finally the results obtained are inversely transformed numerically using the Stehfest formula to get solutions in the time variable. The combined Laplace transform and boundary element method is easy to be implemented and accurate for solving unsteady problems of anisotropic functionally graded media governed by the diffusion convection equation. [ABSTRACT FROM AUTHOR]

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Hydrogel with anisotropic properties has promising potentials, while its fabrication is still challenging. In this work, chitosan fiber (CF) was designed to reinforce polyvinyl alcohol (PVA) hydrogel anisotropically. First, CF was pre‐treated in a weak acidic buffer to create rough surface as well as outward‐stretched chitosan chain end segments, and then mixed with PVA in solution. A PVA/CFs composite hydrogel was thereafter prepared by casting the mixture with a pushing force followed by freeze‐thawing cycles. The microstructure of the composite hydrogel was characterized by scanning electron microscopy, optical microscopy and Fourier transform infrared spectroscopy, and its mechanical properties at the directions parallel to and perpendicular to the casting force were measured. Our results indicate that the pre‐treated CF can reinforce the PVA hydrogel effectively, especially along the casting force direction. The tensile strength, breaking elongation and toughness of the composite hydrogel with only 0.2% CFs at the parallel direction reach 175%, 117% and 244% those of the PVA hydrogel, respectively. The anisotropic reinforcement effect has been understood by the orientating of CFs and the interfacial bonding between the CFs and the PVA matrix. Moreover, bovine serum albumin was released sustainably from the anisotropic hydrogel to indicate its potential application. [ABSTRACT FROM AUTHOR]

Shape morphing materials, especially those fabricated by 4D printing, are gaining much attention due to their versatility of actuation and capability of being programmed in advance. These materials become particularly interesting for biomedical applications where implant materials could be remotely actuated, exerting a force on the surrounding tissues and cells. However, applications in this field have been restricted due to the biocompatibility of the materials and the character of the required stimuli, generally not compatible with physiological environments. Magnetic nanoparticles (MNPs) represent a great opportunity to this end; however, the actuation results in a uniform movement toward the magnet that requires anchoring of the object. Here, for the first time, the application of anisotropic Fe3O4 MNPs is described, and synthesized by a novel and easy route, that can be aligned on pre‐defined patterns within objects printed by digital light processing, resulting in materials that can be actuated remotely (4D printing). These nanoparticles (178 nm × 55 nm), show good biocompatibility when directly seeded on top of human mesenchymal stem cells, despite being uptaken. Most importantly, the alignment of the MNPs can tune the movement of fabricated nanocomposite materials, resulting in complex movements of attraction or repulsion depending on the direction of the applied magnetic field. [ABSTRACT FROM AUTHOR]

In this paper, the flocculation properties of polyethylene oxide (PEO) on kaolinite and the mechanism of adsorption on kaolinite anisotropic substrates were explored. As revealed by the experimental results, the settling rate and removal rate of kaolinite increased with increasing PEO concentration, but too high PEO concentration would cause the small particles to stabilize and become difficult to settle. Furthermore, to probe deep into the interactions between PEO and kaolinite anisotropic substrates, the morphology of adsorbed PEO, interfacial adsorption structure, and dynamic behavior of water molecules were determined by quartz crystal microbalance with dissipation (QCM-D) and molecular dynamics (MD) simulations. The adsorption amount of PEO on different mineral surfaces is in the order of kaolinite > alumina > silica, and the thickness of the adsorption structure formed by alumina is greater than that of silica. As illustrated by the MD simulation results, the adsorption of PEO reduces the concentration of water molecules attached to the kaolinite surface. The PEO forms a double-layer adsorption structure on the 001 surface, while forming a tight monolayer adsorption structure on the 00 1 ¯ surface, weakening the interaction between the surface and the water molecules. The above results demonstrate that the adsorption of PEO effectively weakened the hydration dispersion of kaolinite and promoted the agglomeration of kaolinite particles. [ABSTRACT FROM AUTHOR]

The widespread use of additive manufacturing (AM) has been extensively progressed in the past decade due to the convenience provided by AM in rapid and reliable part production. Fused deposition modeling (FDM) has witnessed even faster growth of application as its equipment is environmentally friendly and easily adaptable. This increased use of FDM to manufacture prototypes and finished parts is accompanied by concerns that 3D printed parts do not perform the same as relatively homogeneous parts produced by molding or machining. As the interface between two faces of bonded material may be modeled by stress elements, in theory, by modeling 3D printed layers subjected to tension at varying angles as transformed stress elements, the stress required to break the layer bonds can be determined. To evaluate such a relationship, in this study, the stresses calculated from stress transformation were compared with the behavior of 3D printed specimens subjected to tensile loads. The maximum principal stress was found to be constant relative to the layer angle, regardless of whether the specimen experienced failure at the layer interface or within the layer material, although the specimens with layers 75° relative to the load were notable exceptions to this finding. This failure at much lower stresses for the samples used in the 75° tests may be attributed to a possible environmental factor, such as temperature or humidity change, degrading the samples' structural integrity. [ABSTRACT FROM AUTHOR]

Accurate predictions of the failure behaviors of quasi-brittle materials are of practical significance to underground engineering. In this work, a novel anisotropic damage model is proposed based on continuous damage mechanics. The anisotropic damage model includes a two-parameter parabolic-type failure criterion, a stiffness degradation model that considers anisotropic damage, and damage evolution equations for tension and shear, respectively. The advantage of this model is that the degradation of elastic stiffness only occurs in the direction parallel to the failure surface for shear damage, avoiding the interpenetration of crack surfaces. In addition, the shear damage evolution equation is established based on the equivalent shear strain on the failure face. A cyclic iterative method based on the proposed anisotropic damage model was developed to numerically simulate the fracture process of quasi-brittle materials. The developed model and method are important because the ready-made finite element software is difficult to simulate the anisotropic damage of quasi-brittle materials. The proposed anisotropic damage model was tested against a conventional damage model and validated against two benchmark experiments: uniaxial and biaxial compression tests and Brazilian splitting tests. The results demonstrate that the proposed anisotropic damage model simulates the mesoscale damage mode, macroscale fracture modes, and strength characteristics more effectively and accurately than conventional damage models. [ABSTRACT FROM AUTHOR]

The anisotropic elastic mechanical properties of a family of single material chiral mechanical metamaterials are explored systematically. An integrated monoclinic-micropolar constitutive model is developed to quantify the anisotropic mechanical properties of the chiral designs with different geometries. The model predictions are thoroughly verified by mechanical experiments on three-dimensional (3D) printed specimens and finite element simulations with periodic boundary conditions. The new integrated monoclinic-micropolar model can predict the anisotropic elastic properties in all directions. Normalized model parameters for this family of chiral designs are provided. Finally, the anisotropic effective stiffness and effective Poisson's ratio of all geometric designs in this family are quantified. The anisotropy and the completeness of auxeticity are evaluated systematically. [ABSTRACT FROM AUTHOR]

Electrical exploration has become an important means of shale gas reservoir exploration and evaluation, and is expected to play a key role in the later stages of reservoir fracturing and development. At present, the research on the electrical response characteristics of shale gas reservoirs and their relationship with reservoir parameters is extensive and in-depth, but there is little research on their complex resistivity anisotropy characteristics and influencing factors, which restricts petrophysical modeling and reservoir parameter prediction, and reduces the reliability of shale gas exploration and reservoir evaluation by electromagnetic methods. In this paper, shale samples from the Longmaxi Formation and the Wufeng Formation of shale gas wells in southern Sichuan were collected, the complex resistivity of 34 shales in bedding direction and vertical bedding direction were measured, and the induced polarization (IP) parameters of shales were extracted by inversion. The electrical anisotropy response characteristics under different temperature and pressure conditions were analyzed, and the influencing factors and laws of complex resistivity anisotropy of shales were revealed. Combined with the test results of shale porosity and permeability, the evaluation model of resistivity, polarizability and porosity and permeability parameters was established. The research results have formed a set of testing methods and analysis techniques for electrical anisotropy of shale reservoirs, which are mainly based on complex resistivity parameter testing. It is helpful to understand the electrical anisotropy characteristics of shale gas reservoirs in southern Sichuan; this will provide the theoretical and physical basis for shale gas reservoir evaluation and fracturing monitoring by electrical exploration. [ABSTRACT FROM AUTHOR]

Myocardial infarction is a leading cause of death worldwide and has severe consequences including irreversible damage to the myocardium, which can lead to heart failure. Cardiac tissue engineering aims to re-engineer the infarcted myocardium using tissues made from human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to regenerate heart muscle and restore contractile function via an implantable epicardial patch. The current limitations of this technology include both biomanufacturing challenges in maintaining tissue integrity during implantation and biological challenges in inducing cell alignment, maturation, and coordinated electromechanical function, which, when overcome, may be able to prevent adverse cardiac remodeling through mechanical support in the injured heart to facilitate regeneration. Polymer scaffolds serve to mechanically reinforce both engineered and host tissues. Here, we introduce a novel biodegradable, customizable scaffold composed of wet-spun polycaprolactone (PCL) microfibers to strengthen engineered tissues and provide an anisotropic mechanical environment to promote engineered tissue formation. We developed a wet-spinning process to produce consistent fibers which are then collected on an automated mandrel that precisely controls the angle of intersection of fibers and their spacing to generate mechanically anisotropic scaffolds. Through optimization of the wet-spinning process, we tuned the fiber diameter to 339 ± 31 µm and 105 ± 9 µm and achieved a high degree of fidelity in the fiber structure within the scaffold (fiber angle within 1.8° of prediction). Through degradation and mechanical testing, we demonstrate the ability to maintain scaffold mechanical integrity as well as tune the mechanical environment of the scaffold through structure (Young's modulus of 120.8 ± 1.90 MPa for 0° scaffolds, 60.34 ± 11.41 MPa for 30° scaffolds, 73.59 ± 3.167 MPa for 60° scaffolds, and 49.31 ± 6.90 MPa for 90° scaffolds), while observing decreased hysteresis in angled vs. parallel scaffolds. Further, we embedded the fibrous PCL scaffolds in a collagen hydrogel mixed with hiPSC-CMs to form engineered cardiac tissue with high cell survival, tissue compaction, and active contractility of the hiPSC-CMs. Through this work, we develop and optimize a versatile biomanufacturing process to generate customizable PCL fibrous scaffolds which can be readily utilized to guide engineered tissue formation and function. [ABSTRACT FROM AUTHOR]

Magnetorheological elastomers (MREs) are well-known for their ability to self-adjust their mechanical properties in response to magnetic field influence. This ability, however, diminishes under high-strain conditions, a phenomenon known as the stress-softening effect. Similar phenomena have been observed in other filled elastomers; hence, the current study demonstrates the role of fillers in reducing the effect and thus maintaining performance. Anisotropic, silicone-based MREs with various carbonyl iron particle (CIP) concentrations were prepared and subjected to uniaxial tensile load to evaluate high-strain conditions with and without magnetic influence. The current study demonstrated that non-linear stress–strain behavior was observed in all types of samples, which supported the experimental findings. CIP concentration has a significant impact on the stress–strain behavior of MREs, with about 350% increased elastic modulus with increasing CIP content. Microstructural observations using field emission scanning electron microscopy (FESEM) yielded novel micro-mechanisms of the high-strain failure process of MREs. The magnetic force applied during tension loading was important in the behavior and characteristics of the MRE failure mechanism, and the discovery of microcracks and microplasticity, which was never reported in the MRE quasi-static tensile, received special attention in this study. The relationships between these microstructural phenomena, magnetic influence, and MRE mechanical properties were defined and discussed thoroughly. Overall, the process of microcracks and microplasticity in the MRE under tensile mode was primarily formed in the matrix, and the formation varies with CIP concentrations. [ABSTRACT FROM AUTHOR]

In this paper, a low-power pulsed laser-induced arc heat source is used to complete the wire-filled additive manufacturing of multi-layer multi-pass stainless steel walls. The low-power pulsed laser can induce and compress the arc to achieve the concentration of arc energy. This paper systematically studied the effects of different deposition paths on the microstructure and mechanical properties. The results show that the parallel deposition mainly consists of columnar grains, and the grain size of the fine grain area is about 10 μm. The longitudinal tensile strength of the parallel part can reach 620 Mpa, and that elongation is 46%. The horizontal tensile strength is 590 MPa and the elongation is only 40%. The alternating deposition part is mainly composed of oriented dendrites, and the grain size of the fine crystal area is about 12 μm. While the average tensile strength of the alternate part is 585 MPa, the average elongation is 38%. The parallel deposition part has better anisotropy, and the isotropy of the alternate deposited part is better. A parallel deposition path is recommended to choose if the component is required to serve under the unidirectional stress state. An alternate deposition path should be adopted if the component is required to serve under the multidirectional stress state. [ABSTRACT FROM AUTHOR]

Despite fatigue free of monolayer graphene, its assemblies, like cellular graphene aerogels (CGA), are usually suffering of frequent fatigue and inherent strength degradation in repeated loading. In this work, by employing multiscale modeling, the highly intrinsic anisotropic mechanical properties of the cell wall due to the layer-by-layer stacked graphene sheets are uncovered, which easily trigger the unique skeleton joints damage during repeated loading and contribute the primary fatigue mechanism of CGA. Conversely, multiscale joint strengthening strategies are proposed by interlayer crosslinking and joint curvation, improving the interlayer interaction, and decreasing interlayer stress during compression, respectively, so as to effectively suppress joint damage to improve fatigue performance of CGA. This work not only clarifies the underlying fatigue mechanism of 2D cellular materials but also highlights optimal design strategies for developing anti-fatigue graphene cellular structures., (© 2024 Wiley‐VCH GmbH.)

Metal halide perovskites (MHPs) have achieved substantial progress in their applications; however, their ionic crystal character and low formation energy result in poor structural stability and limited morphological tunability. In particular, high relative humidity (RH) commonly causes severe MHP degradation, which poses a major obstacle to long-term device operation. Herein, high RH-induced growth of anisotropic MHP structures on glass surfaces is reported under 25 °C and atmospheric conditions on a basis of glass corrosion by moisture. Nanowires (NWs) with tunable length and composition are obtained under 85% RH air, and water molecule-induced facet engineering of perovskite is established for anisotropic growth. Importantly, single-mode photonic lasing in these MHP NWs with thickness at sub-100-nm scale (down to 75 nm ∼ 1/7 lasing wavelength) is achieved via both one-photon and multiphoton pumping. These nanowire lasers exhibited high quality factor (>3000), high degree of polarization (≈0.9), and excellent stability under laser irradiation. The work not only presents a distinctive technique for the growth of MHPs but also endows MHP NWs with new opportunities for nonlinear optics, strong light-matter interactions, and active photonic integrated devices., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Peripheral nerve injury (PNI) and myocardial infarction (MI) are the two most clinically common soft excitable tissue injuries. Both nerve and cardiac tissues exhibit structural anisotropy and electrophysiological activity, providing a wide range of biophysical cues for cell and tissue repair. However, balancing microstructural anisotropy, electroactivity, and biocompatibility is challenging. To address this issue, Dicranopteris linearis (D. linearis) is proposed as a low-perceived value fern plant. Moreover, to enhance its usefulness, it can be designed into a tubular structure and a lamellar structure to bridge the damaged tissue. Therefore, a robust yet simple top-down approach is proposed to designing and fabricating the desired biomimetic versatile hydrogels orienting from the D. linearis to customize for different soft excitable tissue repair applications. These anisotropic electroactive hydrogels performed well as nerve guidance conduits (NGC) and engineered cardiac patches (ECP) in the repair of PNI and MI, respectively. Two birds, one stone. Accordingly, the biomimetic strategy of D. linearis to NGC and D. linearis to ECP is first proposed, opening a new horizon for constructing tissue engineering using natural sources., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

A novel method for complex amplitude manipulation of spin light is proposed based on a double-layer compact anisotropic metasurface. A new degree of freedom (DOF) is introduced through independently rotating the two layers to achieve a full range control of the amplitude. Then additional full range phase shift is further imparted independently based on the traditional Pancharatnam-Berry (PB) phase mechanism by the global rotation of the meta-atom. As a result, the ability of full range and arbitrary complex amplitude manipulation is achieved on meta-atom level. Time consuming massive geometric parameter searching is avoided in the proposed method, which is beneficial to the complicated metadevice design. Based on this theory, two devices for multi-beam generation and Airy beam deflection are designed and experimentally verified, respectively. The good agreement between the calculated and measured results confirms the advantage of the proposed method. Our findings may trigger great interest in high-performance functional metaoptics devices with compact size in integrated systems.

In this article, a new tunable absorber and polarizer using one-dimensional anisotropic graphene photonic crystal (1D AGPC) is proposed for terahertz applications. The optical properties of the 1D AGPC structure is obtained through the transfer matrix method (TMM) calculations. In our design, a single defect layer is introduced in the 1D AGPC structure to increase its absorption. The absorption coefficient is further modified by optimizing the AGPC parameters such as the number of photonic crystal periods, the defect layer thickness, and the chemical potential of graphene. The modified structure can provide perfect absorption with a narrow bandwidth of 0.05 THz. On the other hand, considering the anisotropic optical properties of graphene, polarization dependence of the absorption coefficient is investigated. This feature of the structure can be employed to realize a tunable terahertz polarizer by adjusting incident angle at θ0 = 80°. In this way, high tunable polarization extinction ratio of 6.1 dB to 11.63 dB with respectively very narrow bandwidth of 0.031 THz to 0.023 THz are obtained. The maximum insertion losses within the tunable frequency range are as low as 0.023 dB and 0.031 dB. Hence, our design may have potential applications in narrow-band optoelectronic devices at the terahertz frequency range.

In order to investigate the reflected beam shifts in the anisotropic chiral metamaterial based on the Ωparticle resonance model, we give the expression of the Goos-H?nchen(GH) shifts of reflected beam by using the stationary phase method. The numerical results show that for the incidence of the transverse magnetic wave, the relative GH shifts of co-polarization reflection are enhanced at two Brewster angles, and the enhancement peak of GH shift is larger corresponding to the large Brewster angle. Meanwhile, the enhancement of GH shifts at large Brewster angle is very sensitive to the thickness of the chiral material and incident frequency, the transition of the positive and negative enhancement of the GH shift can be realized by slightly adjusting the thickness or incident frequency. As the incident angle is fixed, the positive and negative transition of the co-polarization GH shifts at different thicknesses can be realized by selecting the appropriate incident frequency. In addition, for the fixed thickness of chiral materials, the positive and negative enhancement of the co-polarization GH shifts at different frequencies can be achieved by modifying the incident angles slightly.

Peripheral nerve regeneration with large defects needs innovative design of nerve guidance conduits (NGCs) which possess anisotropic guidance, electrical induction and right mechanical properties in one. Herein, we present, for the first time, facile fabrication and efficient neural differentiation guidance of anisotropic, conductive, self-snapping, hydrogel-based NGCs. The hydrogels were fabricated via crosslinking of graphitic carbon nitride (g-C3N4) upon exposure with blue light, incorporated with graphene oxide (GO). Incorporation of GO and in situ reduction greatly enhanced surface charges, while decayed light penetration endowed the hydrogel with an intriguing self-snapping feature by the virtue of a crosslinking gradient. The hydrogels were in the optimal mechanical stiffness range for peripheral nerve regeneration and supported normal viability and proliferation of neural cells. The PC12 ​cells differentiated on the electroactive g-C3N4 H/rGO3 (3 ​mg/mL GO loading) hydrogel presented 47% longer neurite length than that of the pristine g-C3N4 H hydrogel. Furthermore, the NGC with aligned microchannels was successfully fabricated using sacrificial melt electrowriting (MEW) moulding, the anisotropic microchannels of the 10 ​μm width showed optimal neurite guidance. Such anisotropic, electroactive, self-snapping NGCs may possess great potential for repairing peripheral nerve injuries.

Elongated ellipsoidal liquid crystal microdroplet reorientation dynamics are discussed in this paper for biosensor applications. To investigate the effect of elongated droplets on nematic liquid crystal droplet biosensors, we simulated a model of a liquid crystal droplet using ellipse geometry. Director reorientation is examined in relation to the elongated droplet shape. In addition, we examined aspect ratio as a factor affecting biosensor response time in relation to surface viscosity and anchoring energy. Finally, the findings suggest that the aspect ratio should be taken into account when designing biosensors. These results can be used to develop more effective biosensors for a variety of applications. This model then predicts the director reorientation angle, which is dependent on the anchoring energy and surface viscosity. This model further suggests that both surface viscosity and homeotropic anchoring energy play an important role when it comes to the director reorientation angle. We developed and applied a nonlinear unsteady-state mathematical model utilizing torque balance and Frank free energy according to the Leslie–Ericksen continuum theory for simulating elongated nematic liquid crystal biosensor droplets with aqueous interfaces. Using the Euler–Lagrange equation, a transient liquid crystal–aqueous interface realignment is modeled by changing the easy axis when surfactant molecules are added to the interface. The realignment at the surface of the droplet is assumed to be driven by the effect of the surfactant, which causes an anchoring transition. According to the results, the response time of the biosensor depends on the aspect ratio. Therefore, the elongation has the potential to control biosensing response time. The result of our study provides a better understanding of director reorientation in elongated liquid crystal droplets in biosensing applications through the numerical results which are presented in this paper.

The complex mechanical properties of coated fabrics make it difficult to obtain accurate constants for design and analysis. A high efficient constitutive model of coated plain-weave fabrics is proposed to realize the prediction of mechanical behaviours in arbitrary directions. The coupling mechanism between macro and meso deformation of coated fabrics is analyzed firstly, and the constitutive relation of the model is established based on mesoscopic parameters with clear physical interpretation. Then, the material property values of specimens are obtained by using a multi-objective optimization algorithm according to the experimental data. Unlike the previous constitutive relations which need to use finite element methods to get numerical solutions, the constitutive relation established in this paper can be mapped to a quartic equation with analytical solution, and the calculation efficiency can be greatly improved. The deviations of model predictions with experimental results, e. g., 0.052 (tension), 0.009 (width), 0.014 (length, warp), 0.025 (length, weft), 0.027 (angle, warp), 0.030 (angle, weft), show that the model predictions are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Current hydrogel or fabric patches for organ repair are generally not designed to conform to the complex mechanics of dynamic organs such as the lung or heart. This study presents a new, biocompatible and bilayered, hydrogel‐based patch platform, consisting of a non‐fouling top layer and a cell adhesive bottom layer, that caters to the anisotropic and auxetic characteristics of dynamic organs. Integrated computational and experimental studies are used to screen over 116 unique anisotropic‐auxetic architectures to establish design rules and tailor the patches to a broad range of target organ dynamics. The patches are then validated in ex vivo and in vivo animal models, where the auxetic patches outperformed non‐auxetic patches in conforming to the volumetric dilation‐contraction of dynamic organs. To further expand the functionality of the auxetic patch platform, novel hole‐filling auxetic patches are developed. These hole‐filling patches composited with fibrin robustly reduce pulmonary air leakage in rats with surgically induced lung puncture. This is the first demonstration of a rational patch design framework that features both anisotropic and auxetic properties to cater to a wide range of organ dynamics. These studies pave the way for future clinical development of biomimetic patches. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with the convergence analysis of a combined finite volume-non-conforming finite element scheme, to approximate the two incompressible phase flow with dynamic capillary pressure in anisotropic porous media. All diffusion terms are anisotropic and heterogeneous and they are discretized by piecewise linear non-conforming triangular finite elements whereas the mobilities are discretized on dual diamond mesh. The mobilities are approximated by a non-standard way considering the inverse of the mean value of the inverse of mobilities across the interface of the dual mesh. This approximation ensures a priori estimates on the global pressure and on the water saturation. Under the assumption of non-degeneracry of mobilities, we prove the convergence of the combined scheme for the complete two-phase flow including the non-equilibrium capillary pressure. [ABSTRACT FROM AUTHOR]