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Foliated rocks are often encountered in underground engineering, and the spatial orientation relationship between its foliation and in situ stress controls the stability of the surrounding rock. This is closely related to the anisotropy of the mechanical properties of foliated rocks. The anisotropic mechanical properties of thin foliated rock under the influences of foliation and stress can be obtained by laboratory testing; however, there have been few experimental studies on foliated rocks under true triaxial compression at present. Foliated rocks are in a three-dimensional unequal stress state in deep excavation engineering; thus, to evaluate the stability of surrounding rock and scientifically guide the support design, a systematic true triaxial test considering the loading orientations (β, ω) of schistosity for a foliated gneiss was conducted. The results show that the strength and failure of the gneiss are greatly affected by inherent structure and stress conditions. More specifically, the larger the ω and σ2, the greater is the strength, and the failure mode tends to be controlled by the differential stress. Finally, a new empirical true triaxial anisotropic failure criterion was proposed according to the variations of strength with loading angle and stress conditions. This criterion can reflect the tendency and sensitivity of the change in the strength to σ2 at different ω and β, and can satisfy the need to model degradation from the true triaxial stress state to the conventional triaxial stress state. This criterion provides a new approach to characterize the strength of anisotropic rocks and improve the design of engineering works in practice.HighlightsThe strength and failure of the foliated gneiss are affected by the loading angle of schistosity structure and differential stress.When the differential stress is larger, the larger the angles ω and β, the more does the failure mode tend to be controlled by stress induction.The strength of the foliated gneiss has a strengthening effect on ω, and the larger the β, the weaker is the strengthening effect of ω.A new empirical true triaxial anisotropic failure criterion is proposed according to the variations of strength with ω, β, and stress conditions.

We propose shortcut to adiabaticity protocols for Bose–Einstein condensates trapped in generalized anisotropic harmonic traps in three dimensions. These protocols enable high-fidelity tuning of trap geometries on time scales much faster than those required for adiabatic processes and are robust across a wide range of interaction strengths, from weakly interacting regimes to the Thomas-Fermi limit. Using the same approach, we also design STA paths to rapidly drive interaction strengths in both isotropic and anisotropic traps. Comparisons with standard linear ramps of system parameters demonstrate significant improvements in performance. Finally, we apply these STA techniques to a unitary engine cycle with a BEC as the working medium. The STA methods significantly enhance the engine’s power output without reducing efficiency and remain highly effective even after multiple consecutive cycles.

The kagome lattice of transition metal atoms provides an exciting platform to study electronic correlations in the presence of geometric frustration and nontrivial band topology 1 – 18 , which continues to bear surprises. Here, using spectroscopic imaging scanning tunnelling microscopy, we discover a temperature-dependent cascade of different symmetry-broken electronic states in a new kagome superconductor, CsV 3 Sb 5 . We reveal, at a temperature far above the superconducting transition temperature T c  ~ 2.5 K, a tri-directional charge order with a 2 a 0 period that breaks the translation symmetry of the lattice. As the system is cooled down towards T c , we observe a prominent V-shaped spectral gap opening at the Fermi level and an additional breaking of the six-fold rotational symmetry, which persists through the superconducting transition. This rotational symmetry breaking is observed as the emergence of an additional 4 a 0 unidirectional charge order and strongly anisotropic scattering in differential conductance maps. The latter can be directly attributed to the orbital-selective renormalization of the vanadium kagome bands. Our experiments reveal a complex landscape of electronic states that can coexist on a kagome lattice, and highlight intriguing parallels to high- T c superconductors and twisted bilayer graphene. A study reveals a temperature-dependent cascade of different symmetry-broken electronic states in the kagome superconductor CsV 3 Sb 5 , and highlights intriguing parallels between vanadium-based kagome metals and materials exhibiting similar electronic phases.

This is the third and final entry in a sequence of papers devoted to the formulation of a theory of self-gravitating anisotropic fluids in Newtonian gravity and general relativity. In the first paper we placed our work in context and provided an overview of the results obtained in the second and third papers. In the second paper we took the necessary step of elaborating a Newtonian theory, and exploited it to build anisotropic stellar models. In this third paper we elevate the theory to general relativity, and apply it to the construction of relativistic stellar models. The relativistic theory is crafted by promoting the fluid variables to a curved spacetime, and promoting the gravitational potential to the spacetime metric. Thus, the director vector, which measures the local magnitude and direction of the anisotropy, is now a four-dimensional vector, and to keep the number of independent degrees of freedom at three, it is required to be orthogonal to the fluid’s velocity vector. The Newtonian action is then generalized in a direct and natural way, and dynamical equations for all the relevant variables are once more obtained through a variational principle. We specialize our relativistic theory of a self-gravitating anisotropic fluid to static and spherically symmetric configurations, and thus obtain models of anisotropic stars in general relativity. As in the Newtonian setting, the models feature a transition from an anisotropic phase at high density to an isotropic phase at low density. Our survey of stellar models reveals that for the same equations of state and the same central density, anisotropic stars are always less compact than isotropic stars.

Herein, we present a new data-driven multiscale framework called FE [Formula omitted] which is based on two main keystones: the usage of physics-constrained artificial neural networks (ANNs) as macroscopic surrogate models and an autonomous data mining process. Our approach allows the efficient simulation of materials with complex underlying microstructures which reveal an overall anisotropic and nonlinear behavior on the macroscale. Thereby, we restrict ourselves to finite strain hyperelasticity problems for now. By using a set of problem specific invariants as the input of the ANN and the Helmholtz free energy density as the output, several physical principles, e. g., objectivity, material symmetry, compatibility with the balance of angular momentum and thermodynamic consistency are fulfilled a priori. The necessary data for the training of the ANN-based surrogate model, i. e., macroscopic deformations and corresponding stresses, are collected via computational homogenization of representative volume elements (RVEs). Thereby, the core feature of the approach is given by a completely autonomous mining of the required data set within an overall loop. In each iteration of the loop, new data are generated by gathering the macroscopic deformation states from the macroscopic finite element simulation and a subsequently sorting by using the anisotropy class of the considered material. Finally, all unknown deformations are prescribed in the RVE simulation to get the corresponding stresses and thus to extend the data set. The proposed framework consequently allows to reduce the number of time-consuming microscale simulations to a minimum. It is exemplarily applied to several descriptive examples, where a fiber reinforced composite with a highly nonlinear Ogden-type behavior of the individual components is considered. Thereby, a rather high accuracy could be proved by a validation of the approach.

The existence of a non-trivial bounded solution to the Dirichlet problem is established for a class of nonlinear elliptic equations involving a fully anisotropic partial differential operator. The relevant operator depends on the gradient of the unknown through the differential of a general convex function. This function need not be radial, nor have a polynomial-type growth. Besides providing genuinely new conclusions, our result recovers and embraces, in a unified framework, several contributions in the existing literature, and augments them in various special instances.

Synthetic aperture radar (SAR) images map Earth’s surface at high resolution, regardless of the weather conditions or sunshine phenomena. Therefore, SAR images have applications in various fields. Speckle noise, which has the characteristic of multiplicative noise, degrades the image quality of SAR images, which causes information loss. This study proposes a speckle noise reduction algorithm while using the speckle reducing anisotropic diffusion (SRAD) filter, discrete wavelet transform (DWT), soft threshold, improved guided filter (IGF), and guided filter (GF), with the aim of removing speckle noise. First, the SRAD filter is applied to the SAR images, and a logarithmic transform is used to convert multiplicative noise in the resulting SRAD image into additive noise. A two-level DWT is used to divide the resulting SRAD image into one low-frequency and six high-frequency sub-band images. To remove the additive noise and preserve edge information, horizontal and vertical sub-band images employ the soft threshold; the diagonal sub-band images employ the IGF; while, the low- frequency sub-band image removes additive noise using the GF. The experiments used both standard and real SAR images. The experimental results reveal that the proposed method, in comparison to state-of-the art methods, obtains excellent speckle noise removal, while preserving the edges and maintaining low computational complexity.

Transversely Isotropic (TI) rocks exhibit anisotropic strength characteristics due to uniform structural features such as foliation, lamination, schistosity, cleavage planes, layering, bedding planes, and stratified layers. In the field of rock engineering, particularly in mining, civil engineering, geology, and petroleum, it is crucial to have a reliable and comprehensive anisotropic failure criterion for TI rocks to support the design process of engineering structures. Therefore, this study aims to develop an anisotropic failure model for TI rocks that integrates new parameters into the intact Hoek and Brown failure criterion. This focus on deriving simplified parameters aims to create a generalized model with improved accuracy in predicting anisotropic strength. The proposed model includes anisotropy factors, such as the unconfined anisotropic strength ( σ c β ) , anisotropic effect ( A e ) , and type of anisotropic curve ( A m ) . Experimental data of layered sandstone tested under various orientations and confining pressures were utilized to validate the model. Additionally, the proposed failure model underwent evaluation using an artificial neural network and published data on layered rocks. The resulting metrics, including R 2 and Root Mean Square Error, were found to be within acceptable standards. This indicates that the proposed criterion can accurately predict failure strength for different rock types.

We present a comprehensive analysis of the anomalous Goos–Hänchen (GH) displacement that occurs during the reflection of light beams at an interface between air and an anisotropic medium. This analysis also applies to the Imbert–Fedorov effect. Our study suggests that the anomalous GH displacement is primarily caused by polarization-dependent abnormal interference effects between the direct and cross-reflected light fields. Using the interface between air and a type II Weyl semimetal as an example, we provide a clear physical explanation for the relationship between spin-dependent abnormal interference effects and anomalous GH displacement. We demonstrate that spin-dependent constructive interference leads to a reduction in the GH displacement of the total reflected light field, while spin-dependent destructive interference results in an increase in the GH displacement of the total reflected light field.

Complex shear wave splitting (SWS) patterns in subduction zones are often interpreted geodynamically as resulting from complex mantle flow; however, this may not always be necessary. We analyzed 7,093 high‐quality SWS measurements from teleseismic S waves recorded by Hi‐net stations across the Ryukyu arc in Japan. Our findings show a systematic rotation of the fast S polarization from trench‐parallel to trench‐perpendicular depending on the earthquake backazimuth. For the same earthquake, the measured splitting patterns also vary spatially across the southwest Japan. Using full‐wave seismic modeling, we showed that a dipping slab with ∼30% shear anisotropy of the tilted transverse isotropy (TTI) type, with a symmetry axis perpendicular to the slab interface, can predict the observed delay times and polarization rotation. Our results highlight the importance of considering dipping anisotropic slabs in interpreting SWS at subduction zones. Plain Language Summary Seismic anisotropy is used to characterize rock fabric, which encodes important information about its stress and deformation history. In an anisotropic rock, seismic waves travel at different speeds along different propagation directions. Furthermore, a shear wave can split into a fast and a slow shear wave after passing through an anisotropic medium, known as shear wave splitting (SWS). While many studies have attributed the observed anisotropy primarily to large‐scale mantle flows around the subducting slab, the role of the subducting slab itself has often been overlooked. Recent research shows shear anisotropy inside slabs to be ∼30% and it is of great scientific value to test if this model can produce the observed complex SWS. To test this hypothesis, we measured SWS patterns recorded by Hi‐net stations in southwest Japan, where shear waves passed through the Ryukyu slab. We found that a dipping anisotropic slab model can explain the observations very well. This work demonstrates that complex SWS patterns could be caused by strong slab anisotropy, not necessarily mantle flows, impacting how we understand mantle dynamics. Key Points We made 7,093 shear wave splitting measurements for teleseismic S waves recorded by Hi‐net stations in Japan We observed that shear wave splitting pattern changes systematically with earthquake backazimuth We can explain this with a dipping slab having ∼30% intra‐slab shear anisotropy, derived from previous analyses of non‐double‐couple earthquake moment tensors