Search Results (223)

How do survivors mourn when violence controls movement, speech, and public grief? This article reads lament as a political–theological practice that keeps the dead publicly addressable under forced (im)mobilities—conditions in which some are deported, disappeared, or killed while others are compelled to remain amid ruins, surveillance, and stigma. Through a comparative reading of Lamentations and Han Kang’s Human Acts, this study develops “fourth-person lament” to name a ruin-saturated address (“you”) that is relayed through multiple voices and across the boundary of death, refusing to resolve responsibility into a single speaker or a finished story. The analysis shows how lament is mediated through bodies that remain—hunger, wounds, exhaustion, unburied dead—and through spaces turned into archives of violence, so that catastrophe cannot be sealed into closure or denial. By tracing struggles over memory and affect—over who may move, who must stay, and whose deaths can appear as grievable—this article argues that lament operates as resistant passage within enforced (im)mobility: a communal and public insistence that memory, mourning, and responsibility remain open to contestation. Full article

To support intelligent and sustainable mine engineering, this geotechnics-based study integrates laboratory testing, three-dimensional numerical simulation, and field monitoring to optimize roadway support and improve resource efficiency. This study investigates the geotechnical behavior of the surrounding rock in coalmine roadways under single-face unloading conditions, aiming to provide theoretical and practical support for surrounding rock control in underground coal mining. Excavation of the roadway creates a free surface, leading to unloading, which makes timely support crucial for preventing instability. True-triaxial single-face unloading tests and mechanical tests on hole-containing coal specimens show that the coal exhibits four characteristic stages, namely fissure compaction (closure), elastic deformation, yielding, and residual strength. Under a confining stress of 4 MPa, the peak strength of Coal Seam No. 3 in the true-triaxial single-face unloading test reached 32.4 MPa, whereas the peak strength of the hole-containing coal specimen was only 17.1 MPa, and failure occurred as instantaneous global instability with an “X”-shaped conjugate shear pattern. Numerical simulations were conducted to optimize the roadway’s surrounding rock control scheme, indicating that increasing the bolt length increases the proportion of the load carried by the rock bolts while reducing the load borne by the cable bolts. In addition, advance abutment pressure increases the forces in the support system and amplifies deformation of the solid rib, coal-pillar rib, and roof; roadway surface convergence is dominated by floor heave. Full article

The oblique water-entry stability of hollow projectiles with different aperture ratios (d/D) and aspect ratios (L/D) is investigated numerically in this study. The effects of aperture and aspect ratios on cavity evolution, hydrodynamic forces, and projectile motion are disclosed and discussed. When aperture ratios vary from 0.2 to 0.7, a larger aperture ratio results in a longer through-hole jet, earlier cavity closure, and a smaller cavity with less vapor. The best water-entry stability with minimal projectile deflection occurs at d/D = 0.3. For d/D > 0.4, the projectile tends to rotate clockwise and touch the surrounding cavity with a rapid increase in the lift, drag, and moment coefficients, accelerating the velocity decay. When aspect ratios vary from 2 to 7, the transition from stability to instability in the projectile motion is predicted at L/D = 2.75~3. A lower aspect ratio (L/D = 2) promotes stable motion with a steady drag coefficient (C_d ≈ 0.9) and negligible lift and moment. In contrast, the instability occurs at L/D = 3. However, when L/D > 3, the water-entry stability is enhanced with the increasing aspect ratio due to greater projectile mass. The inflection points in the hydrodynamic forces are also delayed and the hollow projectiles penetrate further. Full article

P-glycoprotein (P-gp) is an ATP-driven transporter that effluxes a wide range of xenobiotics from cells, and its overexpression is a primary cause of multidrug resistance (MDR) in cancer. It is well-established that P-gp functions through conformational changes, yet its large-scale structural dynamics at work have been unexplored. Here, we directly visualized single P-gp molecules reconstituted in nanodiscs using high-speed atomic force microscopy (HS-AFM). The HS-AFM movies revealed that P-gp is intrinsically dynamic in its apo state, with its nucleotide-binding domains (NBDs) undergoing large, spontaneous opening and closing motions. However, addition of ATP stabilized a conformation characterized by NBD proximity with a strong tendency toward closure. We then leveraged this dynamic viewpoint to elucidate the relationship between Elacridar’s function and the resulting structural dynamics of P-gp. Elacridar is designed to overcome multidrug resistance (MDR) in cancer and acts as a potent dual inhibitor of both P-gp and the Breast Cancer Resistance Protein (BCRP), effectively blocking the drug efflux function of these transporters. This inhibitor has suggested concentration-dependent function: it is effluxed as a substrate at low concentrations and acts as an inhibitor at high concentrations. Our direct observations revealed that low concentrations induced active dynamics in P-gp, whereas high concentrations severely restricted its motion, leading to a rigid, non-productive state. Our study provides critical insights into how observing molecular motion itself can unravel complex biological mechanisms. Full article

Quick visual balance perception in layouts is essential for a positive user experience. However, existing computational models often struggle to accurately capture this key aesthetic aspect, particularly in interfaces with asymmetric elements. This paper introduces Visual Moment Equilibrium (VME), a new cognitive model that redefines visual balance as a unified perceptual force field, similar to moment equilibrium in physical systems. Based on principles from Gestalt psychology, spatial cognition, and psychophysics, we incorporate three main innovations: (1) a Measured Balance index enhanced with psychophysical transformations to enable sensitive quantification of visual imbalance; (2) a nine-grid visual weighting system combined with Manhattan distance to reflect human attentional distribution and non-Euclidean spatial reasoning; and (3) a Shape Sparsity Ratio with a piecewise compensation function that formally operationalizes the Gestalt principle of closure, especially for irregular visual elements. Validation against human perceptual benchmarks from the Analytic Hierarchy Process shows that the VME model has a strong correlation with expert judgments regarding regular interfaces (Pearson’s r = 0.942, accounting for 88.8% of the variance), outperforming the widely used model (33.9%). VME also maintains high predictive accuracy for irregular interfaces (r = 0.890), emphasizing its wide applicability across various design configurations. Full article

A novel hydraulically actuated uniform clamping flange connection mechanism is proposed to address the long-standing challenges in high-pressure natural gas flowmeter calibration, including cumbersome bolt-by-bolt assembly/disassembly, high leakage risk, and severe non-uniform gasket contact pressure associated with conventional multi-bolt flanges. Unlike traditional discrete bolt loading, the proposed mechanism generates a continuous and actively adjustable circumferential clamping force via an integrated hydraulic annular piston, ensuring excellent sealing uniformity and rapid installation within minutes. A high-fidelity transient finite element model of the hydraulic clamping flange assembly is established, incorporating the nonlinear compression/rebound behavior of flexible graphite–stainless steel spiral-wound gaskets and one-way fluid–structure interaction under water hammer loading. Parametric studies reveal that reducing the effective clamping area to below 80% of the original design significantly intensifies stress concentration and compromises sealing integrity, while clamping force below 80% or above 120% of the nominal value leads to leakage or component overstress, respectively. Under steady 10 MPa pressurization, the flange exhibits a maximum stress of 150.57 MPa, a minimum gasket contact stress exceeding 30 MPa, and a rotation angle below 1°, demonstrating robust sealing performance. During a severe water hammer event induced by rapid valve closure, the peak flange stress remains acceptable at 140.41 MPa, while the minimum gasket contact stress stays above the critical sealing threshold (38.051 MPa). However, repeated water hammer cycles increase the risk of long-term gasket fatigue. This study introduces, for the first time, a hydraulic uniform-clamping flange solution that dramatically improves sealing reliability, installation efficiency, and operational safety in high-pressure flowmeter calibration and similar temporary high-integrity piping connections, providing crucial technical guidance for field applications. Full article

This work systematically investigates the high-cycle fatigue (HCF) properties and fatigue crack growth (FCG) behavior of hot-rolled dual-phase (DP) steels with comparable tensile strength but distinctly different yield strength (458 MPa for the FG sample and 355 MPa for the CG sample), grain sizes and morphologies. Contrary to the conventional Hall–Petch relationship, the coarse-grained (CG) sample demonstrates superior fatigue performance. This enhancement is reflected in its higher fatigue strength, combined with an elevated FCG threshold and a reduced FCG rate in the Paris regime of FCG behavior. Fracture morphologies and FCG path analyses reveal that this enhanced fatigue resistance attributes to pronounced crack path tortuosity in the CG microstructure. The tortuous crack path enhances roughness-induced crack closure effects in the near-threshold regime while promoting more frequent crack deflection during stable propagation, collectively reducing the effective driving force for crack growth. The experimental evidence confirms that properly designed CG microstructures with appropriate phase distribution can provide superior fatigue resistance in hot-rolled DP steels. Full article

To address the automation of table grape harvesting, a clamping and cutting integrated, four-point flexible end-effector is designed, based on the biological and mechanical characteristics of grapes. The clamping device is validated in regard to force closure requirements using a force spiral. On this basis, a finite element model of the grape pedicel–blade system is established, and dynamic simulations of pedicel cutting are conducted using ANSYS 2021/LS-DYNA. The simulation results indicate that when the pedicel diameter is 10 mm, the maximum shear stress is 1.515 MPa. A kinematic simulation of the clamping device is performed using ADAMS, producing a contact force curve between the end effector’s finger joints and the grape during the clamping process. The simulation results show that the peak contact force of 11 N is lower than the critical rupture force of the grape (24.79 N), satisfying the requirements for flexible, low-damage harvesting. Furthermore, to address the vulnerability of grapes, a contact-force control system is designed, employing a position–speed–torque three-loop control strategy. Pressure sensors integrated into the four clamping fingers provide real-time feedback to adjust the contact force, ensuring precise clamping control. Finally, a physical prototype of the end effector and controller is developed, and harvesting trials are conducted in a vineyard. The harvesting success rate reaches 96.7%, with an average harvesting time of 13.7 s per trial. The grape cluster damage and berry drop rates are 3.2% and 2.8%, respectively, meeting the expected design requirements. Full article

This study introduces a comprehensive three-dimensional micromechanical framework to capture the nonlinear mechanical behavior of diverse composite materials, including coupled elastic degradation, inelastic strain evolution, and phenomenological failure in their constituents. The primary objective is to integrate a generalized elastic degradation–inelasticity (EDI) model into the parametric high-fidelity generalized method of cells (PHFGMC) micromechanical approach, enabling accurate prediction of nonlinear responses and failure mechanisms in multi-phase composites. To achieve this, a unified three-dimensional orthotropic EDI modeling formulation is developed and implemented in the PHFGMC. Grounded in continuum mechanics, the EDI employs scalar field variables to quantify material damage and defines an energy potential function. Thermodynamic forces are specified along three principal directions, decomposed into tensile and compressive components, with shear failure accounted for across the respective planes. Inelastic strain evolution is modeled using incremental anisotropic plasticity theory, coupling damage and inelasticity to maintain generality and flexibility for diverse phase behaviors. The proposed model offers a general, unified framework for modeling damage and inelasticity, which can be calibrated to operate in either coupled or decoupled modes. The PHFGMC micromechanics framework then derives the overall (macroscopic) nonlinear and damage responses of the multi-phase composite. A failure criterion can be applied for ultimate strength evaluation, and a crack-band type theory can be used for post-ultimate degradation. The method is applicable to different types of composites, including polymer matrix composites (PMCs) and ceramic matrix composites (CMCs). Applications demonstrate predictions of monotonic and cyclic loading responses for PMCs and CMCs, incorporating inelasticity and coupled damage mechanisms (such as crack closure and tension–compression asymmetry). The proposed framework is validated through comparisons with experimental and numerical results from the literature. Full article

Long-span steel roofs with spatial ring beams as their primary load-bearing elements are widely adopted in large stadiums and public facilities. Their construction involves complex stages—ring beam assembly, closure and staged falsework unloading—during which boundary conditions, internal forces and overall stiffness change considerably. This study proposes a stiffness monitoring method that evaluates the self-bearing process of such structures based on measured stress and displacement data. The method establishes a stiffness matrix for different construction stages and introduces an indicator of stiffness change rate to quantify stiffness evolution during unloading. To validate this approach, finite element method simulations were conducted, and their predictions were compared with monitoring data from the Shenzhen Stadium steel roof. The monitored and simulated stiffness variation trends show strong agreement, thereby validating the applicability of the proposed monitoring framework. The method enables real-time tracking of structural safety, supports optimisation of the unloading sequence and enhances our understanding of stiffness evolution during construction. Overall, this study presents a validated, data-driven framework for monitoring and optimising the self-bearing process of long-span steel roof structures, thereby improving both construction safety and service performance. Full article

To investigate characteristic stress and energy evolution law of carbonaceous shale under dry–wet cycles and fissure angle, several samples with prefabricated fissure angles were prepared and subjected to the coupled influence of dry–wet cycles and loading. The results show that the closure stress, initiation stress, damage stress, and peak stress gradually increase with the increase in confining pressure, effectively suppressing the initiation and propagation of the crack. At the same time, the total energy, elastic energy, and dissipated energy at the crack characteristic stress are enhanced by a linear function relationship, significantly improving the bearing capacity and energy storage capacity of carbonaceous shale. The dry–wet cycle is regarded as the driving force of damage, reducing the crack characteristic stress and the total energy, elastic energy, and dissipated energy of crack characteristic stress. This results in a weakened capacity of the rock samples to store elastic strain energy, ultimately contributing to the damage degradation of carbonaceous shale. The anisotropic damage of rock is controlled by fissure angle. The crack characteristic stress and the total energy, elastic energy, and dissipated energy of crack characteristic stress with a 45° fissure angle is the smallest. Finally, the energy storage level at the damage stress (Kcd) can be used as an early warning indicator for rock failure. Full article

To enhance the waterproofing performance of segment bolt holes in shield tunnels and ensure they meet the synergistic waterproofing requirements of segment joint sealing systems, a novel sealing gasket installed at the joint interface of the segment bolt hole has been designed. Numerical analysis was employed for a parametric study of factors influencing the waterproofing performance of the new gasket. Additionally, experimental research was conducted to evaluate its waterproofing capabilities. The study’s findings indicate that the hardness, height, and width of the novel bolt hole waterproof gasket significantly influence both the closure compression force and waterproofing performance. In contrast, the inner diameter primarily affects the closure compression force with a minimal impact on waterproofing performance. Compared to traditional water-swellable gaskets used for segment bolt holes, the novel EPDM (Ethylene Propylene Diene Monomer) waterproof gasket is more effective in mitigating the effects of manufacturing defects. For double-gasket segment joint sealing systems where the waterproofing strength of the bolt hole is critical, the adoption of this novel bolt hole waterproof gasket can better satisfy the synergistic waterproofing requirements between the two sealing gaskets, thereby effectively improving the overall waterproofing capacity of the segment joint sealing system. Full article

The 60 kg/m U75V rail serves as the predominant rail type within China’s high-speed rail network. This study comprehensively evaluates the fatigue behavior of U75V rails through experimental investigations encompassing monotonic tensile testing, high-cycle fatigue characterization, and fatigue crack propagation analysis. All specimens were extracted from standardized 60 kg/m high-speed rail sections to ensure material consistency. Firstly, monotonic tensile tests were conducted to determine the fundamental mechanical properties of the U75V rail. Secondly, uniaxial tension–compression fatigue tests were conducted to establish the S-N and P-S-N relationships of the U75V rail. Lastly, fatigue crack propagation analysis was carried out on three compact tension specimens under three incremental loading forces. Monotonic tensile test results demonstrated full compliance of the material’s basic mechanical properties with Chinese national standards. Fatigue crack propagation results indicated that the crack growth rate of the U75V rail was not only related to the stress-intensity range ∆K but was also correlated with the loading force range ∆F due to a typical crack tip shielding effect, i.e., plasticity-induced crack closure effect. The derived fatigue performance parameters and crack growth mechanism provide essential inputs for predictive fatigue life modeling of high-speed rail infrastructure and development of refined finite element models for fatigue analysis. Full article

Myofibroblasts drive wound healing and fibrotic disease through generation of contractile force to promote wound closure and production of matrix proteins to generate scar tissue. Platelets secrete many pro-wound healing molecules, including cytokines and growth factors. We previously reported that inorganic polyphosphate, secreted by activated platelets, is chemotactic for fibroblasts and induces a myofibroblast phenotype. Using NIH-3T3 cells and primary human fibroblasts, we examined the impact of inhibitors of cell-surface receptors and intracellular signaling molecules on polyphosphate-induced myofibroblast differentiation. We now report that polyphosphate-induced differentiation of fibroblasts to myofibroblasts occurs through a signaling pathway mediated by the receptor for advanced glycation end products (RAGE) and nuclear factor kappa B (NFκB) transcription factor. Inhibition of these signaling components ablated the effects of polyphosphate on fibroblasts. Platelet releasates also induced NFκB signaling and myofibroblast differentiation. Blocking the polyphosphate content of platelet releasates with a biocompatible polyP inhibitor rendered the releasates unable to induce myofibroblast differentiation. These results identify a cell-surface receptor and intracellular transcription factor utilized by platelet polyphosphate to promote wound healing through myofibroblast differentiation and may provide targets for promoting wound healing or altering the disease progression of fibrosis. Full article

Deep coalbed methane reservoirs must utilize hydraulic fracturing technology to create high-conductivity sand-filled fractures for economical development. However, the mechanism by which proppant embedment affects fracture width in coal rock is not yet clear. In this article, using the discrete element particle flow method, we have developed a numerical simulation model that can replicate the dynamic process of proppant embedment into the fracture surface. By tracking particle positions, we have accurately characterized the dynamic changes in fracture width and proppant embedment depth. The consistency between experimental measurements of average fracture width and numerical results demonstrates the reliability of our numerical model. Using this model, we analyzed the mechanisms by which different proppant particle sizes, number of layers, and closure stresses affect fracture width. The force among particles under different proppant embedment conditions and the induced stress field around the fracture were also studied. Numerical simulation results show that stress concentration formed by proppant embedment in the fracture surface leads to the generation of numerous induced micro-fractures. As the proppant grain size and closure stress increase, the stress concentration formed by proppant embedment in the fracture surface intensifies, and the variability in fracture width along the fracture length direction also increases. With more layers of proppant placement, the particles counteract some of the closure stress, thereby reducing the degree of proppant embedment around the fracture surface. Full article