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This paper experimentally investigated the in-plane seismic behavior of perforated masonry walls (pier-spandrel substructures) retrofitted using engineered cementitious composites (ECC). One unreinforced masonry (URM) specimen and two ECC-reinforced masonry substructures were prepared and subjected to pseudostatic cyclic lateral loads. The failure mode, hysteretic curves, strength, deformability, stiffness, and energy dissipation capacity of three specimens were compared and discussed. The results revealed that the failure pattern of masonry pier-spandrel substructure was improved by the ECC layer with shear failure of masonry piers changing to bending failure. Multiple thin cracks were observed on the surface of ECC overlay. Moreover, the external ECC layer effectively increased the load-carrying capacity and ultimate deformation of the substructures, with maximum increases of 104% in strength and 72% in ultimate displacement, respectively. Finally, the excellent energy dissipation capacity was obtained by ECC overlay, which can improve the collapse resistance of masonry structures subjected to strong earthquake action. [ABSTRACT FROM AUTHOR]

Confined brick masonry structures have garnered considerable attention as an effective solution for earthquake-prone regions due to their robust construction, efficient wall-to-column connections, and optimised utilisation of material strength. Within the realm of building design and construction, openings play a pivotal role, serving as essential elements for facilitating natural light and fresh air into the structure. However, the presence of openings within confined brick masonry walls causes a significant reduction in their seismic resistance. Hence, striking the right balance between these openings and structural strength is crucial. For this purpose, it is necessary to investigate the influence of size, shape, and position of the openings in confined brick masonry walls on their seismic performance. In this work, a comprehensive finite element macro-model is adopted that treats the wall and tie members as a unified system. A concrete damage plasticity approach is employed to predict damage progression in confined brick masonry walls. Using a pushover analysis in finite element framework, the ultimate strength, stiffness, and energy absorption capacity of confined brick masonry with different types of openings is assessed. Furthermore, a parametric study is conducted incorporating various scenarios, such as aspect ratios of confined brick masonry walls, diverse shapes of opening and variations in the positions of windows, doors, and combinations of both openings. Based on the results, simplified equations are developed to facilitate analytical estimation of ultimate strength, along with recommendations for optimising opening shape, size, and placement to enhance the design of confined brick masonry walls with openings. The study highlights that larger openings in confined brick masonry walls diminish ultimate strength, stiffness, and energy dissipation due to reduced load distribution and increased stress concentrations. Openings smaller than 10% of the masonry area maintain load paths, but larger openings require additional support. Rectangular openings with greater height than width exhibit superior performance. Furthermore, the positioning of windows significantly influences wall strength, with placements farther from the loading point proving favorable. Door placement also impacts ultimate strength, with central placement compromising stiffness. Combining window openings with a centrally located door maintains consistent ultimate strength but affects stiffness. Overall, this research contributes to a better understanding of the seismic behaviour of confined brick masonry structures with openings, offering valuable insights for engineers and architects working in regions susceptible to seismic activity. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) is widely recognized as a low-cost alternative to iridium as anode electrocatalyst in proton-exchange membrane water electrolyzers (PEMWE). However, the reported Ru-based catalysts usually only operate within tens of hours in PEMWE because of their intrinsically high reactivity of lattice oxygen that leads to irrepressible Ru leaching and structural collapse. Herein, we report a design concept by employing large-sized and acid-resistant lattice lead (Pb) as a second element to induce a pinning effect for effectively narrowing the moving channels of oxygen atoms, thereby lowering the reactivity of lattice oxygen in Ru oxides. The Pb-RuO2 catalyst presents a low overpotential of 188 ± 2 mV at 10 mA cm−2 and can sustain for over 1100 h in an acid medium with a negligible degradation rate of 19 μV h−1. Particularly, the Pb-RuO2-based PEMWE can operate for more than 250 h at 500 mA cm−2 with a low degradation rate of only 17 μV h−1. Experimental and theoretical calculation results reveal that Ru-O covalency is reduced due to the unique 6s−2p−4d orbital hybridization, which increases the loss energy of lattice oxygen and suppresses the over-oxidation of Ru for improved long-term stability in PEMWE. Developing robust catalysts for proton-exchange membrane water electrolyzers is essential for industrial applications. Here, the authors report a Pb-RuO2 catalyst that uses large-sized Pb to reduce the reactivity of lattice oxygen, enhancing stability and allowing it to operate for over 1100 h. [ABSTRACT FROM AUTHOR]

The current industrial wireless sensor network (IWSN) cluster routing methods suffer from energy inefficiency. Designing efficient cluster-based routing protocols is crucial for improving network performance and energy efficiency. Therefore, this paper first designs a new clustering model to achieve efficient cluster head (CH) selection and data transmission performance by comprehensively considering multiple key factors such as CH energy, base station (BS) distance, packet loss rate, and data delay. Based on this clustering model, a novel cluster routing protocol based on Gaussian mutation adaptive artificial fish swarm algorithm (GAAFSA) is proposed. At the same time, a new Gaussian mutation strategy and an adaptive strategy were introduced to effectively promote the protocol to avoid local optima and prevent premature convergence. The GAAFSA based cluster routing protocol was experimentally compared with five popular schemes, namely CMSTR, D2CRP, EEHCHR, ESCVAD and BAFSA. The results showed that the proposed protocol outperformed the other four schemes in terms of network energy consumption, system lifetime, data transmission reliability, and latency. Specifically, GAAFSA has improved network lifespan by at least 15.68%, BS received packets by at least 7.46%, and reduced packet loss rate by at least 15.28%. Therefore, GAAFSA effectively optimizes network performance and extends network lifespan, greatly reducing energy loss within the network and significantly improving network quality of service (QoS). [ABSTRACT FROM AUTHOR]

To investigate the dynamic mechanical behavior and energy dissipation characteristics of low-temperature rock samples under cyclic impact loading, a temperature-controlled impact system that combines Hopkins bars with a low-temperature compensation device was used. Five temperature gradients were confirmed via a trial impact test, and impact tests were conducted under two kinds of impact air pressures. The macroscopic damage characteristics of rock samples under cyclic impact at different temperatures, dynamic stress-strain curves, changes in peak stress and strain, energy dissipation, and cumulative damage at different temperatures, and the macroscopic and microscopic structural characteristics of low-temperature rock samples after cyclic impact were analyzed in combination with damage. The findings indicated that low-temperature saturated granite primarily experienced tensile damage under cyclic impact loading, with the required number of impacts increasing with decreasing temperature, and rock samples exhibited freeze-induced brittleness and significantly increased fragmentation. The dynamic stress-strain curve generally exhibited rebound characteristics in the post-peak stage. With an increasing number of cycles, an overall decrease in peak stress was observed, whereas the peak strain and cumulative specific dissipated energy exhibited opposite trends. This trend was more pronounced at lower temperatures, with a significant increase in peak strain and specific energy amplitude. In addition, the cumulative damage factor of the rock samples increased at lower temperatures, consistent with macroscopic damage characteristics, and exhibited a negative correlation with peak stress. The degree of crack extension in the macroscopic samples corresponded with the observed fracture changes. Microanalysis (SEM) indicated that decreasing temperature resulted in freeze brittleness of the fracture surfaces, characterized by reduced flatness and an expansion of brittle cracks across the damage surface. The slip separation phenomenon became increasingly pronounced, and these observations were positively correlated with the cumulative damage value. [ABSTRACT FROM AUTHOR]

This study establishes a finite element model based on the Iwan model to accurately characterize the force–displacement relationship and energy dissipation in bolted joints under small-amplitude tangential displacement. The force–displacement behavior of the Iwan model is transformed into a stress–strain relationship using a hybrid hardened intrinsic model. A subroutine developed with UMAT and UHARD is used to simulate the elastic–plastic behavior of the Iwan model during surface contact in the finite element model. Three-dimensional modeling and joint simulation are conducted using ABAQUS software. Experimental data verify the model's validity, and the effects of multiple factors on the bolted bonding surface are analyzed. The influence of friction coefficient, cyclic displacement amplitude, and preload on the force–displacement relationship of the bolted bonding surface is explored. Polynomial interpolation of the loading and unloading curves is applied to investigate the energy dissipation phenomenon. Results show that the finite element method can effectively reflect the hysteresis and energy dissipation behavior of the bonding surface. Increased friction coefficient and preload improve residual stiffness and energy dissipation capacity, while larger cyclic displacement amplitudes increase energy dissipation but have a minimal effect on residual stiffness. [ABSTRACT FROM AUTHOR]

High-efficiency microcalorimeter arrays are required as imaging spectroscopy for X-ray microscopy in general and for astrophysics. We have developed in-house an array of Transition Edge Sensor (TES) X-ray microcalorimeters with mushroom-type absorbers which have a large area of 260 μ m square with multiple support stems. Insufficient thermal conductivity may degrade the energy resolution. We construct a 3D FEM simulation with thermal conduction and electric feedback circuit of TES. Estimated physical parameters were incorporated into the simulation to reproduce the measured pulse waveforms. As a result, the effect of the large absorber on the degradation of energy resolution was small for the mushroom-type absorber TES calorimeter. [ABSTRACT FROM AUTHOR]

Mixing discrete flexible fibres into sand may improve its liquefaction resistance during cyclic loading. Here, the benefits are demonstrated by performing undrained cyclic triaxial tests on fibre-reinforced samples in very loose and loose states. The development of a liquified state may be delayed when fibres are present. Here, the strain energy dissipation during loading, and liquefaction development, is focused on. The results show that strain energy continuously dissipates as undrained cyclic loading proceeds. The capacity energy, which coincides with a double amplitude axial strain of 5% or the unity of excess pore pressure ratio ( r u ), whichever occurs first, is increased by the inclusion of fibres. Under the two-way symmetrical cyclic loading, with a cyclic stress ratio of 0.2, the inclusion of fibres with a fibre content of 0.5% leads to the capacity energies of the samples in very loose and loose states increasing by 86.8 and 158.8%, respectively. The generation of pore pressure is closely related to the dissipated energy. The fibres alter the liquefaction responses of a sand skeleton in ways that depend on the applied loading conditions, and this depends on the extent to which the fibres are mobilized in tension during loading. When unities of r u are attained for fibre-reinforced sand samples, their states may vary greatly and remain far from liquefaction. A newly defined pore pressure ratio ( r u ∗) proves to be a better indicator of liquefaction in fibre-reinforced sand. A possible energy-based method, intended for practical use to assess liquefaction resistance of fibre-reinforced sand, and the margin of safety against liquefaction, is also presented. [ABSTRACT FROM AUTHOR]

This study uses numerical simulations to investigate projectile shape's influence on the ballistic performance of 3D shallow bend-joint woven fabrics (3DSBWFs). The projectiles, including conical, flat, hemispherical, and spherical shapes, were analyzed for their impact on energy absorption, stress distribution, and deformation mechanisms. Results indicated that flat projectiles exhibited the highest total energy absorption, reflecting extensive energy transfer and broad impact force distribution. In contrast, conical projectiles caused localized energy absorption, concentrating stress at the tip and leading to early rupture of fabric yarns through minimal energy dissipation. Hemispherical and spherical projectiles demonstrated balanced energy absorption and uniform impact force distribution. Stress propagation varied significantly, with conical projectiles causing localized damage, while flat projectiles displayed broader stress propagation. Deformation patterns also differed, with conical projectiles causing severe localized deformation and flat projectiles resulting in extensive yarn deformation. Hemispherical and spherical projectiles induced more balanced deformations. These findings underscore the importance of projectile shape in designing protective materials, providing insights for optimizing fabric structures to enhance ballistic performance. [ABSTRACT FROM AUTHOR]

Underground mining disasters are generally caused by the deterioration in mechanical properties of coal and overlying rock exposed to mining loading–unloading, while their differential mechanical deterioration and catastrophe mechanisms are not well understood. Therefore, a series of uniaxial loading–unloading tests with ultrasonic monitoring are performed on coal and roof sandstone, while the mechanical responses are investigated using energy-based damage analysis and ultrasonic characterization method. The sandstone yields a greater strength and deformation modulus and experiences a brittle failure, while the coal possesses a larger Poisson's ratio and undergoes a ductile failure. A higher (lower) crack initiation (damage) ratio in coal reflects its faster crack propagation than sandstone. Energy evolution analysis shows that coal has a poorer elastic energy storage capacity, but its energy dissipation is severer. The energy-type catastrophe criteria for coal and sandstone are derived based on an elastic energy ratio. A new damage variable is defined by the cumulative dissipated energy and total input energy, and the damage energy release rate is introduced to develop a damage evolution model under uniaxial loading–unloading condition, from which it is indicated that the coal experiences a greater damage degree, but is less dependent on energy release rate. Furthermore, the differential energy controlling mechanisms of instability between coal and sandstone are revealed, i.e., the coal is controlled by pre-peak energy dissipation and post-peak energy release, while the sandstone is dominated by post-peak rapid energy release. Meanwhile, different wave velocity evolution patterns are generalized, where the denser sandstone yields a higher stress sensitivity of wave velocity. The structural degradation process is quantitatively characterized by using a combination of dynamic elastic parameters, intactness index, and disturbance damage factor. The structural deterioration occurs in the unloading and final loading failure stages, where coal shows a progressive pattern, while sandstone possesses a transient pattern. Finally, the quantitative relationships between wave velocity and stress, energy and damage are established. Highlights: Lithology significantly affects mechanical responses during uniaxial loading-unloading. Both stiffness enhancement and loss occur in a single uniaxial loading-unloading cycle. Failure mechanisms are governed by the interaction between energy dissipation and release. [ABSTRACT FROM AUTHOR]

Xuan paper is a classic Chinese handmade paper with long history and has been listed as a national intangible cultural heritage since 2009, which is mainly composed of wingceltis (Pteroceltis tatarinowii) phloem fibers and straw fibers. Due to the unique properties of wingceltis phloem fibers, Xuan paper is spotless, flexible, stable, and durable, and is widely used by calligraphers, painters, or museums for restoration. Uncovering the variation of phloem fiber properties throughout the traditional pulping process is essential for a comprehensive understanding of the special performance of Xuan paper. In this study, chemical, structural, and mechanical characterization was conducted on the raw bark (phloem fiber), treated phloem fiber, and pulp fiber at different steps of the traditional pulping process for making Xuan paper. The compositional and morphological analysis revealed the effective removal of the matrix polymers, while the phloem fiber almost retained the original fiber structure during the traditional process. Wide-angle X-ray scattering results indicated that the relative crystallinity of cellulose increased and crystals expanded after the lime cooking and exposure to sun and rain. Compared to the raw phloem fibers, the ultimate stress and tensile stiffness of pulp fibers decreased by 24.35% and 9.79%, respectively. However, the fracture strain and fracture toughness of pulp fibers showed a drastic promotion, which might be attributed to the energy dissipation caused by the cell wall structure, the breaking and reforming of hydrogen bonds, and the slipping and rearrangement of cellulose microfibrils. [ABSTRACT FROM AUTHOR]

In this paper, the bone tissue was modeled as a linear viscoelastic material saturated with interstitial fluid. We considered a specific case of harmonic loading and related the mechanical stimuli to the loading frequency. In this way, we could include the inertial effect in the model while not having to deal with the perturbation during each loading period. Two types of mechanical signals were considered: strain energy and dissipation energy. A parametric study revealed the dependency of the two signals on loading frequency and material property. The evolution of the apparent mass density supported the parametric study's findings. Under the three different frequency loadings, the strain energy-stimulated samples experienced identical remodeling scenarios. The samples stimulated with dissipation energy, on the other hand, exhibited a strong frequency dependence. An additional study was performed to investigate the effect of long-term variations in the loading frequency on the remodeling process. This demonstrated the model's capabilities in designing and evaluating load regimes for rehabilitation following a bone injury or bone reconstruction. [ABSTRACT FROM AUTHOR]

The current investigation deals with the deformation of a non-homogeneous thermoelastic half space under hydrostatic initial stress for the Green–Naghdi model III. The medium is supposed to be rotating with a constant angular velocity. The non-homogeneous properties of the material are along the x-direction. At the first instance, the problem has been solved analytically to obtain stress and displacement components. Further, the numerical values of these expressions are evaluated using a computer program for a particular medium. The numerical values obtained are then presented graphically to show the effect of initial stress parameter and non-homogeneity parameter on the quantities. [ABSTRACT FROM AUTHOR]

The discrete element method (DEM) is used to simulate the behavior of a model sand under cyclic stress. Two approaches are employed in the contact model to account for the effect of anisotropic particle shape: (1) spheres with a rolling resistance moment and (2) clumps of spheres. Model parameters are calibrated using experimental results from drained monotonic triaxial tests on NE34 sand. Then, a series of cyclic triaxial tests is done on a homogeneous elementary volume sample with varying density index ( I D ) and cyclic stress ratio (CSR). Both macroscopic and micromechanical characteristics of the material are examined under cyclic loads. In particular, the evolution of Young’s modulus (E) and the damping ratio (D) with strain amplitude are evaluated at varying I D and compared with values from the literature. An analysis of the coordination number (Z), orientation of strong and weak contact forces, friction mobilization, sliding contacts and fabric evolution links the observed macroscopic behavior of energy dissipation to the phenomenon of frictional sliding at the grain scale. [ABSTRACT FROM AUTHOR]

The conservative Allen-Cahn equation satisfies three important physical properties, namely the mass conservation law, the energy dissipation law, and the maximum bound principle. However, very few numerical methods can preserve them at the same time. In this paper, we present a multi-physical structure-preserving method for the conservative Allen-Cahn equation with nonlocal constraint by combining the averaged vector field method in time and the central finite difference scheme in space, which can conserve all three properties simultaneously at the fully discrete level. We propose an efficient linear iteration algorithm to solve the presented nonlinear scheme and prove that the iteration satisfies the maximum bound principle and a contraction mapping property in the discrete L ∞ norm. Furthermore, concise error estimates in the maximum norm are established on non-uniform time meshes. The theoretical findings of the proposed scheme are verified by several benchmark examples, where an adaptive time-stepping strategy is employed. [ABSTRACT FROM AUTHOR]

Aggregates consisting of submicron-sized cohesive dust grains are ubiquitous, and understanding the collisional behavior of dust aggregates is essential. It is known that low-speed collisions of dust aggregates result in either sticking or bouncing, and local and permanent compaction occurs near the contact area upon collision. In this study, we perform numerical simulations of collisions between two aggregates and investigate their compressive behavior. We find that the maximum compression length is proportional to the radius of aggregates and increases with the collision velocity. We also reveal that a theoretical model of contact between two elastoplastic spheres successfully reproduces the size- and velocity-dependence of the maximum compression length observed in our numerical simulations. Our findings on the plastic deformation of aggregates during collisional compression provide a clue to understanding the collisional growth process of aggregates. [ABSTRACT FROM AUTHOR]

In wireless sensor networks (WSNs), data aggregation techniques are used to reduce energy consumption of the sensors and extend the network lifetime. Recent work in this area considers the utilization of external mobile agents (elements) in data aggregation to further improve the WSN lifespan. The sensitivity of data collected by WSNs varies based on the application environment, necessitating data aggregation that adheres to specific conditions and constraints. One of the challenges in using external mobile elements is establishing trust between these elements and WSNs to ensure that data aggregation conditions set by the WSNs are met. In this paper, we propose a fog-cloud framework for a distributed trust service that enables WSNs to recruit trusted mobile elements for data aggregation. Our proposed trust framework provides WSNs with the flexibility to align their trust policy with the conditions of their data aggregation processes, facilitating efficient access to trust services. Simulation results demonstrate that our framework reduces energy loss while ensuring consistent and reliable data aggregation in WSNs. [ABSTRACT FROM AUTHOR]

To investigate the mechanical and energy dissipation characteristics of gray sandstone at critical failure, dynamic impact compression tests were conducted under different axial pressure and confining pressure levels. The critical energy dissipation density of gray sandstone under different dynamic-static combination loading conditions was determined, and an empirical model for predicting the critical energy dissipation density was established. The conclusions of the current research are: (1) the dynamic peak stress increases and then decreases with increasing axial pressure and increases with increasing confining pressure. The axial pressure turning points of dynamic peak stress from strong to poor under 4 MPa, 8 MPa, and 12 MPa confining pressure conditions were 22.54 MPa, 22.05 MPa, and 23.64 MPa, respectively. (2) The second type of cut line modulus increases and then decreases with the increase of axial pressure, showing a quadratic law of change. (3) When there is no axial pressure, the critical energy dissipation density increases and then decreases with the increase of confining pressure, showing an exponential function change rule. Under the condition of axial pressure, the critical energy dissipation density increases with the increase of confining pressure, showing the change rule of logarithmic function, and increases with the increase of axial pressure and then decreases, showing the change rule of quadratic function. (4) Under the conditions of confining pressure of 4 MPa, 8 MPa, 12 MPa, and axial pressure of 25.00 MPa, 28.33 MPa, and 20.00 MPa, the critical dissipation densities reached the maximum values of 7.01 J cm−3, 7.38 J cm−3, and 8.40 J cm−3, respectively. The empirical model can better predict the critical absorbed energy density of gray sandstone under different dynamic and static combinations loading conditions. [ABSTRACT FROM AUTHOR]

Against conventional wisdom, corrugated grain boundaries in polycrystalline graphene, grown on Pt(111) surfaces, are shown to exhibit negative friction coefficients and non-monotonic velocity dependence. Using combined experimental, simulation, and modeling efforts, the underlying energy dissipation mechanism is found to be dominated by dynamic buckling of grain boundary dislocation protrusions. The revealed mechanism is expected to appear in a wide range of polycrystalline two-dimensional material interfaces, thus supporting the design of large-scale dry superlubric contacts. This work demonstrates non-Amontons frictional behavior and negative differential friction coefficients at graphene/Pt(111) surface grain boundaries due to dynamic buckling of dislocations, providing vital insights for the design of macroscopic dry superlubric contacts. [ABSTRACT FROM AUTHOR]

The transport of charged particles, which can be described by the Maxwell–Ampère Nernst–Planck (MANP) framework, is essential in various applications including ion channels and semiconductors. We propose a decoupled structure-preserving numerical scheme for the MANP model in this work. The Nernst-Planck equations are treated by the implicit exponential time differencing method associated with the Slotboom transform to preserve the positivity of the concentrations. In order to be effective with the Fast Fourier Transform, additional diffusive terms are introduced into Nernst–Planck equations. Meanwhile, the correction is introduced in the Maxwell–Ampère equation to fulfill Gauss’s law. The curl-free condition for electric displacement is realized by a local curl-free relaxation algorithm whose complexity is O(N). We present sufficient restrictions on the time and spatial steps to satisfy the positivity and energy dissipation law at a discrete level. Numerical experiments are conducted to validate the expected numerical accuracy and demonstrate the structure-preserving properties of the proposed method. [ABSTRACT FROM AUTHOR]

The combination of plasma technology with microfluidics has gained significant attention in recent years. The unique characteristics of microfluidic chips, such as high surface-to-volume ratio and efficient mass transfer, coupled with plasma's ability to provide the necessary green energy for the degradation of complex molecules, make this combination promising for water and wastewater treatment applications. A gas/liquid biphasic dielectric barrier discharge (DBD) plasma microreactor powered by a nano-pulsed excitation source, at atmospheric pressure, was used to study the degradation of p-benzoquinone and caffeine in water, chosen as model molecules for water pollution. Based on High Performance Liquid Chromatography (HPLC) analyses, the argon plasma was able to completely degrade both molecules at concentrations 10− 5, 10− 4 and 10− 3 mol/L. At higher concentration (10− 2 mol/L), the plasma promotes the synthesis of hydroquinone from p-benzoquinone. A 50% mineralization is achieved after plasma for the caffeine in aqueous solution at 10− 5 M. [ABSTRACT FROM AUTHOR]

The complex relationship between the gut microbiome and host metabolic health has been an emerging research area. Several recent studies have highlighted the potential effects of the microbiome's diversity, composition and metabolic production capabilities on Body Mass Index (BMI), liver health, glucose homeostasis and Type-2 Diabetes (T2D). The majority of these studies were constrained by relatively small cohorts, mostly focusing on individuals with metabolic disorders, limiting a comprehensive understanding of the microbiome's role in metabolic health. Leveraging a large-scale, comprehensive cohort of nearly 9000 individuals, measured using Continuous Glucose Monitoring (CGM), Dual-energy X-ray absorptiometry (DXA) scan and liver Ultrasound (US) we examined the functional profile of the gut microbiome, and its relation to 38 metabolic health measures. We identified 145 unique bacterial pathways significantly correlated with metabolic health measures, with 86.9% of these showing significant associations with more than one metabolic health measure. Furthermore, 87,678 unique bacterial gene families were found to be significantly associated with at least one metabolic health measure. Notably, "key" bacterial pathways such as purine ribonucleosides degradation and anaerobic energy metabolism demonstrated multiple robust associations across various metabolic health measures, highlighting their potential roles in regulating metabolic processes. Our results remained largely unchanged after adjustments for nutritional habits and for BMI they were replicated in a geographically independent cohort. These insights pave the way for future research and potentially the development of microbiome-targeted interventions to enhance metabolic health. Here, employing a large cohort of nearly 9000 individuals, the authors reveal associations between gut microbiome functions and metabolic measures, highlighting bacterial gene families and pathways affecting host metabolic health. [ABSTRACT FROM AUTHOR]

The frame beam anchor plate is a new supporting structure reinforcing fill slopes. At present, only a few studies have evaluated its static stability based on the two-dimensional plane assumption. In this paper, the limit analysis method is combined with the three-dimensional spiral failure mechanism to evaluate the factor of safety (Fs) of a slope supported by a frame beam anchor plate. The pseudo-static approach is used to express the seismic effects. When calculating the internal energy dissipations, both the pull-out failure of anchor plates and tensile failure of tie rods are considered. The accuracy of the approach is verified by comparison with calculation results from the finite element method. Parameter analysis summarizes the influence law of each supporting structure design parameter on the Fs. Therefore, this study develops a theoretical basis for evaluating slope stability reinforced by frame beam anchor plates, which can better guide the design of slopes reinforced by this supporting structure. [ABSTRACT FROM AUTHOR]

Optimization algorithms are essential tools used to address real-world problems through minimization or maximization processes. In the context of photovoltaic (PV) systems, various optimization algorithms have been employed to extract solar cell parameters using minimization techniques, and to identify the maximum power point (MPP) using maximization approaches. However, under partial shading conditions or during rapidly changing irradiance, many of these algorithms tend to get trapped in local minima, failing to locate the global maximum power point (GMPPT). This shortcoming leads to significant energy losses from PV cells. Similarly, the extraction of solar cell parameters is often compromised by the random search behavior and inadequate exploration and exploitation capabilities of many existing algorithms. The Jellyfish Search Optimization (JSO) algorithm is a recent, parameter-free method developed to tackle a wide range of optimization problems. Despite its innovative design, JSO is prone to premature convergence and exhibits a longer convergence time. To address these limitations, this paper proposes a modified version of the JSO algorithm, which integrates the state-of-the-art features of JSO with the Lévy flight characteristic from the cuckoo search algorithm. This combination aims to achieve a better balance between exploration and exploitation. To validate the effectiveness of the proposed Improved Jellyfish Search Optimization (IJSO) algorithm in PV systems, extensive experiments were conducted. These experiments included benchmarking with complex test functions, extracting cell parameters using various solar cell models, and maximizing energy output from PV systems under different environmental conditions. The results demonstrate that the proposed IJSO algorithm effectively enhances parameter extraction and global maximum power point tracking, making it a promising solution for optimizing energy extraction from PV cells in dynamic conditions. [ABSTRACT FROM AUTHOR]

The high non-radiative energy loss is a bottleneck issue that impedes the improvement of organic solar cells. The formation of triplet exciton is thought to be the main source of the large non-radiative energy loss. Decreasing the rate of back charge transfer is considered as an effective approach to alleviate the relaxation of the charge-transfer state and the triplet exciton generation. Herein, we develops an efficient ternary system based on D18:N3-BO:F-BTA3 by regulating the charge-transfer state disorder and the rate of back charge transfer of the blend. With the addition of F-BTA3, a well-defined morphology with a more condensed molecular packing is obtained. Moreover, a reduced charge-transfer state disorder is demonstrated in the ternary blend, which decreases the rate of back charge transfer as well as the triplet exciton formation, and therefore hinders the non-radiative recombination pathways. Consequently, D18:N3-BO:F-BTA3-based device produces a low non-radiative energy loss of 0.183 eV and a record-high efficiency of 20.25%. This work not only points towards the significant role of the charge-transfer state disorder on the suppression of triplet exciton formation and the non-radiative energy loss, but also provides a valuable insight for enhancing the performance of OSCs. The high non-radiative energy loss is a bottleneck issue for efficient organic solar cells. Here, the authors regulate the charge transfer state disorder and rate of back charge transfer through a ternary system, achieving low non-radiative energy loss of 0.183 eV and device efficiency of 20.25%. [ABSTRACT FROM AUTHOR]

Dielectric ceramics possess a unique competitive advantage in electronic systems due to their high-power density and excellent reliability. Na1/2Bi1/2TiO3-based ceramics, one type of extensively studied energy storage dielectric, however, often experience A-site element volatilization and Ti4+ reduction during high-temperature sintering. These issues may result in increased energy loss, reduced polarization and low dielectric breakdown electric field, ultimately making it challenging to achieve both high energy storage density and efficiency. To address these issues, we introduce a synergistic optimization strategy that combine polarization engineering and grain alignment engineering. First principles calculations and experimental analyses show that the doping of Mn2+ can suppress the reduction of Ti4+ in Na1/2Bi1/2TiO3-based ceramics and enhance ion off-centering displacements, thereby reducing energy loss and improving polarization. In addition, we prepared multilayer ceramic capacitors with grains oriented along the <111> direction using the template grain growth method. This approach effectively reduces electric-field-induced strain by 37% and markedly enhances breakdown electric field by 42% when compared with nontextured counterpart. As a result of this comprehensive strategy, <111 >-textured Na1/2Bi1/2TiO3-based multilayer ceramic capacitors achieve an ultra-high energy density of 15.7 J·cm−3 and an excellent efficiency beyond 95% at 850 kV·cm−1, exhibiting a superior overall energy storage performance. Grain alignment and polarization engineering were simultaneously utilized to enhance the energy storage performance of Na1/2Bi1/2TiO3-based multilayer ceramic capacitors, leading to an energy density of 15.7 J·cm−3 and energy efficiency over 95%. [ABSTRACT FROM AUTHOR]

Introduction: Unregulated expiratory flow may contribute to ventilator-induced lung injury. The amount of energy dissipated into the lungs with tidal mechanical ventilation may be used to quantify potentially injurious ventilation. Previously reported devices for variable expiratory flow regulation (FLEX) require, either computer-controlled feedback, or an initial expiratory flow trigger. In this bench study we present a novel passive expiratory flow regulation device. Methods: The device was tested using a commercially available mechanical ventilator with a range of settings (tidal volume 420 ml and 630 ml, max. inspiratory flow rate 30 L/min and 50 L/min, respiratory rate 10 min−1, positive end-expiratory pressure 5 cmH2O), and a test lung with six different combinations of compliance and resistance settings. The effectiveness of the device was evaluated for reduction in peak expiratory flow, expiratory time, mean airway pressure, and the reduction of tidal dissipated energy (measured as the area within the airway pressure–volume loop). Results: Maximal and minimal reduction in peak expiratory flow was from 97.18 ± 0.41 L/min to 25.82 ± 0.07 L/min (p < 0.001), and from 44.11 ± 0.42 L/min to 26.30 ± 0.06 L/min, respectively. Maximal prolongation in expiratory time was recorded from 1.53 ± 0.06 s to 3.64 ± 0.21 s (p < 0.001). As a result of the extended expiration, the maximal decrease in I:E ratio was from 1:1.15 ± 0.03 to 1:2.45 ± 0.01 (p < 0.001). The greatest increase in mean airway pressure was from 10.04 ± 0.03 cmH2O to 17.33 ± 0.03 cmH2O. Dissipated energy was significantly reduced with the device under all test conditions (p < 0.001). The greatest reduction in dissipated energy was from 1.74 ± 0.00 J to 0.84 ± 0.00 J per breath. The least reduction in dissipated energy was from 0.30 ± 0.00 J to 0.16 ± 0.00 J per breath. The greatest and least percentage reduction in dissipated energy was 68% and 33%, respectively. Conclusions: The device bench tested in this study demonstrated a significant reduction in peak expiratory flow rate and dissipated energy, compared to ventilation with unregulated expiratory flow. Application of the device warrants further experimental and clinical evaluation. [ABSTRACT FROM AUTHOR]

In this work, the concept of peer-to-peer energy sharing in wildlife communication systems is explored. In this context, wild animals can share energy wirelessly besides their data communications as they opportunistically come into range of each other. Our goal is to find a way to balance the energy among the nodes and minimize this energy loss. We propose a novel encounter-based energy-sharing scheme, called EBES, that utilizes single and multi-hop transmission to achieve energy balance, minimize energy losses, and maximize the lifetime of the wildlife communication system. EBES is based on a variety of parameters, including the amount of energy left in the system and the nodes' encounter rate, and buffer sizes. In the simulation studies, we considered a wildlife communication network that is involved in data communication and applied EBES over the opportunistic routing protocols such as EBR, Spray&Wait, and Epidemic resulting in a network lifetime increase of 35% and improving the routing protocols performance. Additionally, we compared EBES with the other well-known energy balancing techniques that also contribute to data communication such as EA-Epidemic, EERPFAnt, and OE-OLSR and the results show the remaining energy was improved by 31%, 26%, and 15%, respectively. [ABSTRACT FROM AUTHOR]

Microfine mineral particles have a small size, light weight, and low inertia, making it difficult for them to deviate from streamlines and collide with bubbles. Conventional flotation operations consume a large amount of reagents and exhibit poor flotation indicators. This study employs computational fluid dynamics (CFD) simulation and hydrodynamic testing to investigate the flow field within a high-turbulence microfine particle flotation machine equipped with a multilayer impeller–stator configuration, and validates the practical application performance of the microfine particle flotation machine through single-batch flotation experiments. Result shows that the impeller region of the traditional mechanical stirring flotation machine has a turbulent energy dissipation rate of 20 m²/s³, whereas that for the microfine particle flotation machine averages over 120 m²/s³. In the flotation verification, the cumulative recovery rate of the fine particle flotation machine is increased by 28% compared with that of the traditional KYF flotation machine. The flotation rate is also 1.3 times that of the KYF, demonstrating stronger selectivity for fine particle concentrates. It has certain guiding significance for the resource utilization of fine particle minerals. [ABSTRACT FROM AUTHOR]

The quality factor Q is a dimensionless measure of the energy loss per cycle of a wave field, and a proper understanding of this factor is important in a variety of fields, from seismology, geophysical prospecting to electrical science. Here, the focus is on viscoelasticity. When interpreting experimental values, several factors must be taken into account, in particular the shape of the medium (rods, bars or unbounded media) and the fact that the measurements are made on stationary or propagating modes. From a theoretical point of view, the expressions of Q may differ due to different definitions, the spatial dimension and the inhomogeneity of the wave, i.e. the fact that the vectors of propagation (or wavenumber) and attenuation do not point in the same direction. We show the difference between temporal and spatial Q, the relationships between compressional and shear Q, the dependence on frequency, the case of poro-viscoelasticity and anisotropy, the effect of inhomogeneous waves and various loss mechanisms, and consider the analogy between elastic and electromagnetic waves. We discuss physical theories describing relaxation peaks, bounds on Q and experiments showing the behaviour of Q as a function of frequency, saturation and pore pressure. Finally, we propose an application example where Q can be used to estimate porosity and saturation. [ABSTRACT FROM AUTHOR]

Context: In this study, the structural, elastic, electronic, and optical properties of Cs2GeBeBr6 and Cs2SnBeBr6 halide double perovskites (HDPs) were investigated using density functional theory (DFT) calculations. Notably, the Tran-Blaha modified Becke-Johnson (TB-mBJ) method was employed to predict indirect band gaps of 2.434 eV for Cs2GeBeBr6 and 2.855 eV for Cs2SnBeBr6. The stability of these compounds in a cubic (Fm-3m) structure was confirmed through formation energy, cohesive energy, tolerance factor, and elastic constants. Furthermore, the ductile nature of the materials was demonstrated through Poisson's and Pugh's ratios. Our optical property analysis, spanning the 0–13 eV energy range, revealed key insights into the dielectric functions, extinction coefficient, electron energy loss, refractive index, optical conductivity, reflectivity, and absorption coefficient. These results highlight the potential of Cs2GeBeBr6 and Cs2SnBeBr6 for future optoelectronic and photovoltaic applications. Methods: In this investigation, we employed density functional theory (DFT), implemented using the Wien2k package. The exchange and correlation potentials were treated using the generalized gradient approximation (GGA) and the Tran-Blaha modified Becke-Johnson (TB-mBJ) method. To evaluate dynamic stability, we analyzed the phonon band structures using the CASTEP code. [ABSTRACT FROM AUTHOR]

This research explores the impact of earthquake directionality and orientation on the seismic performance of reinforced concrete (RC) frame structures, an area previously overlooked in seismic design. The multi-directional component of ground motion was not taken into consideration during the seismic performance design of the majority of RC frame structures. Focusing on a case study in Padang City, Indonesia, a region known for moderate seismic activity, this study assesses the behavior of an eight-story ordinary moment resisting frame (OMRF) under various directional components and orientation angles of ground motions. Through Nonlinear Dynamic Analysis (NL-DA) using Nonlinear Time History Analyses (NL-THA), the study incorporates 14 ground motions across East–West and North–South directions, varying from 0° to 60° in 15-degree increments. Incremental Dynamic Analysis (IDA) evaluates the building's response, employing capacity curves, fragility curves, and CMR scores to understand damage probabilities and structural behaviors under different earthquake directions. The objectives include (1) assessing the building's seismic resilience through IDA capacity curves in line with FEMA 356 performance-based design standards, (2) developing fragility curves and the CMR to predict the potential of damages and structural response in various ground motion directions, and (3) formulating a generic relationship between intensity measure (IM), structural behavior (SB), and incidence angle (θ) via regression analysis. Results highlight the crucial role of θ in influencing structural response, with deterioration in structural behavior noted as the angle of incidence increases. This pattern underscores the varying stress distributions and deformation patterns in response to directional ground movements. The study's findings emphasize incorporating directionality in seismic risk assessments and structural designs, offering valuable insights for improving resilience against future seismic events. Eventually, the link between θ, IM, and SB is crucial for assessing and mitigating seismic risk, since it indicates that θ is a major element impacting how buildings respond to seismic occurrences. [ABSTRACT FROM AUTHOR]

Seismic-resistant self-centering concentrically braced frames (SC-CBFs) are susceptible to the concentration of inter-story drifts during earthquakes owing to the relatively low energy dissipation ability of braces. To address this limitation, this study proposed a novel solution by designing a strong backup (SB) system to mitigate inter-story deformation concentration in "weak" stories. The proposed SB system consisting of truss members can be attached to the existing SC-CBF through pin connections, forming a system, termed strong backup SC-CBF (SC-CBF-SB), to promote a more uniform distribution of inter-story drifts along the height of the frame and mitigate the weak story behavior. A six-story chevron-braced frame is adopted to investigate the seismic performance of SC-CBF and SC-CBF-SB. Finite element models of SC-CBF and SC-CBF-SB are built. The mechanical characteristics and dynamic responses of the SC-CBF-SB are examined. To comprehensively evaluate the performance of both SC-CBF and SC-CBF-SB, static pushover analyses and nonlinear time-history analyses are conducted. Additionally, incremental dynamic analysis (IDA) is performed to evaluate the responses (particularly drift concentration) of both frame types subjected to increasing seismic intensity levels. Numerical results show that the maximum value of the drift concentration factor (DCF) is around 1.3 and 1.8 for SC-CBF-SB and SC-CBF, respectively, indicating that SC-CBF-SB can effectively mitigate inter-story drift concentration of SC-CBF. Meanwhile, the proposed SB system has a minimal negative impact on the favorable SC ability of the frame. [ABSTRACT FROM AUTHOR]

This study analyzes the secular dynamics of two extended bodies in Keplerian orbits, focusing on tidal effects. It introduces formulas for energy dissipation within each body in a binary system. The bodies can have a finite number of layers with linear viscoelastic rheology. The layers must be sufficiently coupled so that the rotation of each layer remains close to the average rotation of the body. The body is assumed to be in a "viscous regime" (though it may contain purely elastic layers), meaning that the relaxation times of the rheology are much shorter than the typical despinning time and deviations from sphericity are caused only by tidal and centrifugal stresses. The main contribution of this paper is the decomposition of orbital-averaged equations into a fast–slow system. This reduction allows the slow dynamics to be represented as sliding along a torque-free curve with occasional jumps at folding points. This greatly simplifies the analysis of the dynamics as a function of the rheological parameters. [ABSTRACT FROM AUTHOR]

Different methods are possible for estimating tidal deformations of Earth and telluric planets. On the one hand, the code ALMA 3 solves analytically the governing equations in considering symmetrical and incompressible bodies with homogeneous layers and different possible rheologies. Tidal deformations are considered with periodic excitation functions and the output of the model is frequency-dependent complex Love numbers. On the other hand, the 3-D finite element code CitcomSVE integrates numerically the governing equations with possibly lateral variations in viscoelastic structures on the regional and global scales. In this work, we present how tidal deformations have been implemented in CitcomSVE by the introduction of a periodic forcing potential. For validation and benchmarking, we realized comparisons between the ALMA 3 output for Moon tidal deformations and the numerical CitcomSVE in terms of frequency-dependent Love numbers k 2 and h 2 real and imaginary parts with 1-D viscoelastic structure. Considering two possible profiles for the Moon,we compared the frequency-dependent quality factor deduced from ALMA 3 with the one obtained with CitcomSVE. We found that with a sufficient numerical resolution for CitcomSVE (with an horizontal resolution of about 14 km and 10 - 5 for numerical accuracy), the results of the two methods for computing tidal deformations (i.e., k 2 and h 2 ) and quality factor Q are in good agreement for different periods including the monthly period (less than 0.025% for the real part of Love numbers and for the Q, about 1% for periods of excitation from 5 to 10 8 days). We also computed tidal dissipation energy from CitcomSVE and found it consistent with that expected from quality factor calculation. Our study demonstrates the potential for CitcomSVE to be applied for planetary tidal deformation calculations for a planet with a 3-D structure. [ABSTRACT FROM AUTHOR]

This study focuses on variations in the hysteretic behavior of buckling-restrained braces (BRBs) configured with or without out-of-plane eccentricity under cyclic loading. Quasi-static experiments and numerical simulations were carried out on concentrically and eccentrically loaded BRB specimens to investigate the mechanical properties, energy dissipation performance, stress distribution, and high-order deformation pattern. The experimental and numerical results showed that compared to the concentrically loaded BRBs, the stiffness, yield force, cumulated plastic ductility (CPD) coefficient, equivalent viscous damping coefficient and energy dissipation decreased, and the yield displacement and compression strength adjustment factor increased for the eccentrically loaded BRBs. With the existence of the out-of-plane eccentricity, the initial yield position changes from the yield segment to the junction between the yield segment and transition segment under a tensile load, while the initial high-order buckling pattern changes from a first-order C-shape to a second-order S-shape under a compressive load. [ABSTRACT FROM AUTHOR]

Metastasis is one of the main causes of relapse and subsequent high mortality from cancer. Metastases can contain very few cells and spread throughout the body. Despite the existing variety of diagnostic imaging methods, in practice, the resolution of note of them allows unambiguously diagnosing the presence of a tumor (clump of cancer cells) smaller than 1–2 mm in size. After surgery and tumor removal, patients are typically offered chemotherapy, external beam radiation therapy, or - or -emitter radionuclide therapy. This therapy has side effects that lead to additional risks and may interfere with continued treatment. Recently, a number of works, in contrast to the traditional approach, have proposed using short-range radionuclides instead of - or -emitters [1–3]. It is convenient to use Auger or conversion electron emitters as short-acting therapeutic agents. Auger electrons and conversion electrons have a short range and high specific linear energy loss in biological tissue: they are capable of damaging cells within a few tens of microns, but do not have a radiotoxic effect over long distances, without damaging healthy cells and tissues. The most efficient and convenient Auger and conversion electron emitters for practical use include Rh ( min), which has the lowest ratio of the number of quanta to electrons [1] and can be obtained by a generator method. The predecessors of Rh ( min) in the generator can be Ru ( days) or Pd ( days). In order to clarify the prospects for producing these precursors, we have measured the rates of Ru() Ru and Pd() Pd reactions upon neutron irradiation of metal ruthenium of natural isotopic composition and metal palladium, enriched in the Pd isotope to 96.36 , in a horizontal experimental channel of the IR-8 reactor. [ABSTRACT FROM AUTHOR]

An investigation into the optical and mechanical properties of a novel borate glasses with the chemical composition of 70 B2O3-10 Li2O-10ZnO-5Bi2O3-5CaO-xEu2O3 was conducted. The glassy specimens of Eu3+-doped borate were prepared by the melting-quenching technique. An enhanced density from 3.0860 to 3.2176 g cm−3 and reduced molar volume from 29.27819 to 29.17447 (cm3 mol−1) are the outcome of increasing the concentration of Eu3+ in glasses. Plotting the extinction coefficient, dielectric constant (ε1, ε2), and refractive index (n) against wavelength reveals that they all rise as level of Eu3+ elements in the glass lattice increases. An increase in Eu3+ concentration results in a decrease in both the volume (VELF) and surface (SELF) energy loss functions. Also, all elastic-mechanical moduli (such as Young's, Bulk, Shear, and Elongation) increase with increasing the quantity of Eu3+ ions in the glass lattice. The Young's modulus (Y, GPa) of the glassy specimens was 34.512, 36.089, 36.504, 36.730 and 37.114 GPa for x equal 0, 0.25, 0.5, 0.75 and 1 mol ratio in the glass system, and coded by Eu-0.0, Eu-0.25, Eu-0.5, Eu-0.75 and Eu-1.0, respectively. Growing Eu2O3 levels resulted in an increase in Micro-Hardness from 2.050 to 2.146 GPa. Poisson's ratio values for Eu-0.0, Eu-0.250, Eu-0.5, Eu-0.75 and Eu-1.0 were 0.273, 0.275, 0.277, 0.277 and 0.278, respectively. [ABSTRACT FROM AUTHOR]

The extraction of thick coal seams at high intensity inevitably leads to more severe strata pressure, especially when influenced by adjacent goaf areas. The combination of multiple strata pressures results in significant deformation of the surrounding rock along the goaf roadway. In order to the problem of large deformation of the surrounding rock of the gob-side roadway, this study proposes a novel method for protecting gob-side roadway using energy-gathering blasting (EGB) to cut roof and relieve pressure, which combines parallel pull-rods fracture theory with the Weibull strength of rock microelements to establish a new energy-gathering blasting model. The optimal spacing of blast holes is determined and the correlation between damage degree and energy-absorbing coefficient as well as explosive center distance is analyzed. Numerical simulation methods are employed for validation, and the results demonstrate that the EGB technique effectively blocks the transmission of stress in non-energy-absorbing directions, further enhancing energy accumulation in the energy-gathering direction. This leads to slower attenuation of effective stress and particle vibration velocity in the energy-gathering direction, promoting the directional expansion of energy-gathering fractures and revealing the mechanical mechanism of energy-gathering fracture directional expansion. Based on this technology, a method for relieving overburden pressure in the surrounding rock is proposed. Through EGB technique cutting the long cantilever structure of thick and hard rock layers is snapped, force them to collapse and expand, thereby supporting the overlying structure and reducing stress concentration in the roadway's surrounding rock. This method reveals the mechanism of pressure unloading in the mining area after roof cutting. Furthermore, based on theoretical analysis, the parameters for roof-cutting pressure unloading are designed, and engineering practice confirms the successful reduction of stress on both sides of the roadway ahead of the working face, optimizing the stress environment of the roadway and achieving the goal of protecting the tests have validated the effectiveness of the method, significantly reducing stress and deformation in the surrounding rock of the roadway. The research findings provide a scientific basis for controlling roadway deformation under similar conditions. Highlights: A new EGB method is proposed based on characteristics of rock. A novel damage model for EGB has been constructed by combining the rock micro element strength with the tension rod fracture theory. The application of EGB method in coal mining can effectively reduce mine pressure and protect roadway. [ABSTRACT FROM AUTHOR]

The freeze–thaw (FT) cycle will lead to rock damage and cause hidden danger to the safety of rock engineering. In order to explore the FT damage characteristics of rocks in cold regions, 0, 20, 30, 40 and 50 FT cycle tests and uniaxial compression tests were carried out on intact and single-fracture cyan specimens with crack inclination angle β of 0°, 45° and 90°, respectively, to study the FT damage problems of rocks from the aspects of physical, mechanical and energy characteristics. The results show that the FT damage of cyan sandstone specimens is mainly dominated by the mechanical action of water–ice phase transition, resulting in relatively little influence on the saturation weight. The porosity of the cyan sandstone specimen increases gradually with the increase of FT cycle, and it has an exponential function relationship with the peak strength, Hoek–Brown model parameter s and energy storage limit, which also implies their variation with the increase of FT cycle. Based on Lemaitre's strain equivalent hypothesis and energy dissipation principle, FT-stress damage models of intact and fractured rocks are established. It is found that the initial damage and critical damage are positively correlated with the number of FT cycles and negatively correlated with crack inclination angle. With initial damage as the characteristic parameter, a critical damage model for rocks subjected to FT cycles is proposed based on the test data and data obtained from existing references. In addition, a normalized degradation equation for the peak strength and energy storage limit of FT-damaged rocks under uniaxial compression is proposed based on classical damage mechanics and critical damage model, and its applicability is verified by test data and relevant data from references. In general, the results of this study can provide a reference for the study of FT damage of rocks in cold regions, and be conducive to clarifying the relationship between FT damage of rocks and the deterioration of mechanical properties and energy storage capacity. Highlights: The change of peak strength, apparent stiffness, Hoek Brown model parameter were discussed. The energy accumulation effect, energy storage limit, peak dissipated energy and energy dissipation effect were analyzed. A freeze–thaw-stress damage model for intact and fractured rocks was established, the concepts of initial and critical damage were introduced. The critical damage model of FT damaged rocks was obtained and discussed. The normalized degradation equations of peak strength and energy storage limit of FT damaged rocks are proposed. [ABSTRACT FROM AUTHOR]

Supramolecular polymer networks (SPNs) are celebrated for their dynamic nature, yet they often exhibit inadequate mechanical properties. Thus far, the quest to bolster the mechanical resilience of SPNs while preserving their dynamic character presents a formidable challenge. Herein, we introduce [2]rotaxane into SPN to serve as another cross-link, which could effectively enhance the mechanical robustness of the polymer network without losing the dynamic properties. Compared with SPN, the dually cross-linked network (DPN) demonstrates superior breaking strength, Young's modulus, puncture force and toughness, underscoring its superior robustness. Furthermore, the cyclic tensile tests reveal that the energy dissipation capacity of DPN rivals, and in some cases surpasses, that of SPN, owing to the efficient energy dissipation pathway facilitated by [2]rotaxane. In addition, benefiting from stable topological structure of [2]rotaxane, DPN exhibits accelerated recovery from deformation, indicating superior elasticity compared to SPN. This strategy elevates the performance of SPNs across multiple metrics, presenting a promising avenue for the development of high-performance dynamic materials. [ABSTRACT FROM AUTHOR]

We consider the Cahn–Hilliard/Navier–Stokes system with non–degenerate mobility in the space–periodic case, describing the flow of two viscous immiscible and incompressible Newtonian fluids with matched densities. We identify sufficient conditions on the velocity field for weak solutions to satisfy an energy identity, improving previous results on the literature. [ABSTRACT FROM AUTHOR]

In this paper, an extension of the Timoshenko model for plane beams is outlined, with the aim of describing, under the assumption of small displacements and strains, a class of dissipative mechanisms observed in cementitious materials. In the spirit of micromorphic continua, the modified beam model includes a novel kinematic descriptor, conceived as an average sliding relevant to a density of micro-cracks not varying along time. For the pairs of rough surfaces, in which such a distribution of micro-cracks is articulated, both an elastic deformation and a frictional dissipation are considered, similarly to what occurs for the fingers of the joints having a tooth saw profile. The system of governing differential equations, of the second order, is provided by a variational approach, endowed by standard boundary conditions. To this purpose, a generalized version of the principle of virtual work is used, in the spirit of Hamilton–Rayleigh approach, including as contributions: (i) the variation of the inner elastic energy, generated by the linear elasticity of the sound material and, in a nonlinear way, by the mutual, reversible deformation of the asperities inside the micro-cracks; (ii) the virtual work of the external actions consistent with the beam model, i.e., the distributed transversal forces and the moments per unit lengths; besides these two contributions, constituting the conservative part of the system, (iii) the dissipation due to friction specified through a smooth Rayleigh potential, entering a nonlinear dependence of viscous and Coulomb type on the sliding rate. Through a COMSOL Multiphysics implementation, 1D finite element analyses are carried out to simulate structural elements subjected to three- and four-point bending tests with alternating loading cycles. The dissipation of energy is investigated at varying the model parameters, and the predictions turn out to be in agreement with preliminary data from an experimental campaign. The present approach is expected to provide a valuable tool for the quantitative and comparative assessment of the hysteresis cycles, favoring the robust design of cementitious materials. [ABSTRACT FROM AUTHOR]

This sentence discusses a possible solution to overcome the disadvantages of traditional eccentrically braced frame systems (EBFs). The proposed solution involves separating the shear links from the frame beams and utilizing double-tube buckling restrained braces with contact rings. These modifications aim to improve the overall performance of the frame system. To investigate the mechanical characteristics of this structural system, an experimental study was conducted, involving the design of two K-type EBFs and testing four distinct replaceable shear links. The stress distribution, load–displacement curves, and hysteresis curves of this structural system were obtained by conducting cyclic lateral loading tests on these specimens. Subsequently, the hysteretic properties, load bearing capacity, and deformation capacity of the member underwent analysis. An exploration was conducted into the primary influences on the structural mechanical characteristics. The research indicates that the double-tube buckling restrained braces with contact ring enhance the structural strength and synergistically perform with shear links to dissipate energy, while ensuring improved performance. Comparison of the date of different parameters shear links shows that the placement of stiffening rib increased the energy dissipation performance by 41.2% and shear capacity by 14.6% for the same sectional dimension of shear links. In the shear links with two stiffening ribs, the larger sectional dimension improved the energy dissipation performance by 11.3% relative to the shear links with smaller sectional dimension. For the shear links with one stiffening rib, the increase in sectional dimension, on the contrary, reduced the energy dissipation performance by 18.4% [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of acid corrosion on mechanical properties and fractal characteristics of red sandstone. The mineral composition of red sandstone was analyzed using X-ray diffraction. The mechanical properties and acoustic emission (AE) signals of red sandstone specimens corroded by sulfuric acid solution with pH values of 1, 3, and 5 for 30 days were determined by uniaxial compression test and AE technique. The energy dissipation law and the fractal damage characteristics of red sandstone specimens after acid corrosion were analyzed based on the energy and fractal theories. The results indicated that the compressive strength and elastic modulus of red sandstone specimens corroded by acid solution decreased. In addition, the peak strain increased, the cumulative AE ringing count decreased, and the duration of high-level AE ringing shortened. These phenomena became more pronounced as the acidity of the solution increased. The peak values of the total energy and the elastic strain energy of the acid-solution-corroded red sandstone specimens decreased. The energy absorption capacity and energy storage limit of rock specimens also decreased. The fractal dimension and the degree of fragmentation decreased with the dissipated energy used for fragmentation. This research provides valuable insights into the prevention and control of sub-surface geotechnical hazards in acid rain-prone areas. [ABSTRACT FROM AUTHOR]

Under the influence of geostress, the thick hard sandstone roof layer at the upper end of the mining area is prone to faults, rockbursts, and sudden collapses during deep coal mining. Blasting top-cutting and depressurization technology centered on over-the-top deep hole blasting is an important method for this type of dynamic disaster control. To characterize the pore structure of sandstone damaged by blast loads and the change in energy dissipation in different pressure environments, specimens with different degrees of blasting damage were measured via nuclear magnetic resonance (NMR) spectroscopy. A triaxial test loading device was used to carry out compression tests on undamaged, vibration-damaged, and blast-damaged specimens under different pressures. The effects of blast load and confining pressure on the porosity, pore structure, energy dissipation, and fracture morphology characteristics of sandstone specimens were analyzed. (1) The T2 spectral curves of the sandstone specimens were all bimodal, and the signal intensity of the main peak was much greater than that of the secondary peak. The peak T2 spectrum curves of the blast-damaged specimens and vibration-damaged specimens were 1.21 and 1.14 times greater than those of the undamaged specimens, respectively, and the mean values of the peak relative area were 1.11 and 1.20 times greater than those of the undamaged specimens, respectively. The number of internal pores in the specimens increased significantly after blast loading. (2) The pore structure distributions in the sandstone specimens were dominated by the proportions of micropores and small holes. The blast load changed the internal pore ratio structure of the specimen, transformed the small holes into medium holes and large holes, and increased the porosity of the specimen. (3) Blast load damage could reduce the energy absorption and energy storage effects of sandstone specimens and weaken roof sandstone and reduce the stress concentration. Furthermore, the impact of the blasting damage area was greater than that of the vibration damage area. (4) With increasing confining pressure, the fracture degree of the specimen first decreased and then increased. Due to the high-energy storage abilities of the undamaged specimens, the macroscopic rupture degrees of the undamaged specimens were greater than those of the specimens damaged by vibration and blasting. The blasting load will cause damage to the roof sandstone to achieve the effect of pressure relief, so as to reduce the occurrence of geological disasters such as roof fault and rock burst. [ABSTRACT FROM AUTHOR]

A local design scheme for origami energy dissipation braces was proposed by combining local Miura units at both ends and a straight segment in the middle. This design was implemented to address the issue of uneven axial stiffness observed in global origami braces. Globally and locally designed origami braces were simulated and compared under cyclic loading to validate the advantages of the proposed design scheme in terms of hysteretic properties. Additionally, an analysis was conducted on the designed braces with varying straight segment lengths, geometric angles, and origami plate thicknesses for comparison. Results indicate that the local design significantly increases the tensile bearing load, enhances the anti-buckling capability, and improves the energy dissipation performance compared to the global design. The positive impact on bearing capacity and energy dissipation performance was observed with increased straight segment length, geometric angles, and origami plate thickness. However, excessively large parameter values result in brace buckling under compression, diminishing energy dissipation capacity. [ABSTRACT FROM AUTHOR]

In this paper, the structural performances of steel plate shear walls employing web plates with rectangular, triangular (zigzag), trapezoidal, and sinusoidal corrugation patterns under monotonic loading are investigated. Several significant structural response parameters including buckling stability, stiffness, strength, serviceability, and energy dissipation capability are considered in this research endeavor. The results of this study provide crucial insights into the behavior of corrugated-web steel shear walls with varying infill plate shapes and thicknesses. It is shown that corrugated-web shear walls predominantly undergo local and/or interactive buckling modes, while flat-web systems exhibit more of a global buckling behavior. Additionally, corrugated infill plates substantially enhance the overall capacity of the system, with the rectangular pattern exhibiting the highest strength, surpassing the flat-web panels by approximately 11 times for a 2-mm web-plate thickness. Assessment of the energy absorption capacity reveals the superior performance of the rectangular pattern for web thicknesses between 2.0 and 3.0 mm. From the load–displacement responses, it is found that increasing of the web thickness significantly enhances the strength and stiffness performances and the base shear capacity is improved by 42% while increasing the thickness from 1.5 to 3.0 mm. These results demonstrate the importance of proper design and detailing in ensuring the desirable and high performance of corrugated-web steel shear walls as promising lateral force-resisting systems. [ABSTRACT FROM AUTHOR]

Ultra-low friction is crucial for the anti-friction, anti-wear, and long-life operation of nanodevices. However, very few two-dimensional materials can achieve ultra-low friction, and they have some limitations in their applications. Therefore, exploring novel materials with ultra-low friction properties is greatly significant. The emergence of ternary two-dimensional materials has opened new opportunities for nanoscale ultra-low friction. This study introduced nickel phosphorous trisulfide (NiPS3, referred to as NPS), a novel two-dimensional ternary material capable of achieving ultralow friction in a vacuum, into the large nanotribology family. Large-size and high-quality NPS crystals with up to 14 mm × 6 mm × 0.3 mm dimensions were grown using the chemical vapor transport method. The NPS nanosheets were obtained using mechanical exfoliation. The dependence of the NPS nanotribology on layer, velocity, and angle was systematically investigated using lateral force microscopy. Interestingly, the coefficient of friction (COF) of NPS with multilayers was decreased to about 0.0045 under 0.005 Pa vacuum condition (with load up to 767.8 nN), achieving the ultra-low friction state. The analysis of the frictional dissipation energy and adhesive forces showed that NPS with multilayers had minimum frictional dissipation energy and adhesive forces since the interlayer interactions were weak and the meniscus force was excluded under vacuum conditions. This study on the nanoscale friction of a ternary two-dimensional material lays a foundation for exploring the nanoscale friction and friction origin of other two-dimensional materials in the future. [ABSTRACT FROM AUTHOR]

The research of rolling mill vibration theory has always been a scientific problem in the field of rolling forming, which is very important to the quality of sheet metal and the stable operation of equipment. The essence of rolling mill vibration is the transfer of energy, which is generated from inside and outside. Based on particle damping technology, a dynamic vibration absorber (DVA) is proposed to control the vertical vibration of roll in the rolling process from the point of energy transfer and dissipation. A nonlinear vibration equation for the DVA-roller system is solved by the incremental harmonic balance method. Based on the obtained solutions, the effects of the basic parameters of the DVA on the properties of vibration transmission are investigated by using the power flow method, which provides theoretical guidance for the selection of the basic parameters of the DVA. Furthermore, the influence of the parameters of the particles on the overall dissipation of energy of the particle group is analyzed in a more systematic way, which provides a reference for the selection of the material and diameter and other parameters of the particles in the practical application of the DVA. The effect of particle parameters on roll amplitude inhibition is studied by experiments. The experimental results agree with the theoretical analysis, which proves the correctness of the theoretical analysis and the feasibility of the particle damping absorber. This research proposes a particle damping absorber to absorb and dissipate the energy transfer in rolling process, which provides a new idea for nonlinear dynamic analysis and stability control of rolling mills, and has important guiding significance for practical production. [ABSTRACT FROM AUTHOR]