Search Results (88)

Bio-inspired helicoidal laminates can redirect damage under transverse loading, but their response as sandwich face sheets remains unclear because the core changes both deformation and load transfer. This study experimentally and numerically investigated the quasi-static penetration of 73-ply carbon/epoxy laminates and Nomex honeycomb sandwich panels with cross-ply, quasi-isotropic, uniform helicoidal (5°, 10°, and 20°), and hybrid helicoidal layups. A fully ply-resolved model was developed for the monolithic laminates, whereas an eight-sublaminate model with an explicitly represented honeycomb core was used for the sandwich panels. H73(10–5) achieved the highest monolithic-laminate peak load of 5.23 kN, 46.1% above CP73 and 35.5% above QI73. The sandwich panels exhibited two load peaks separated by a core-crushing plateau. S-H73(5–10) produced the highest first peak load of 8.99 kN, while S-H73(10–5) achieved the highest penetration energy of 108.37 J. Experiments, simulations, and fractographic observations showed that the intact core constrained upper-face-sheet bending and promoted localized indentation-assisted punching-shear perforation. The crushed core subsequently transferred load to the lower face sheet, which failed through bending- and membrane-dominated tearing. Full article

Classical continuum descriptions based on homogenized parameters, such as modulus and relative density, become inadequate when performance is governed by deliberately engineered multiscale architecture rather than by composition, as in hierarchical and fractal-inspired mechanical metamaterials. In these materials, geometry couples deformation across length scales in ways that single-scale models cannot capture. This review synthesizes theoretical, numerical, and experimental literature published mainly over the last two decades, with emphasis on the last five years. It draws preferentially on peer-reviewed journal articles and highly cited studies; strictly periodic single-scale metamaterials and general electromagnetic–metamaterial literature are cited only where needed to establish historical context and are not otherwise within the scope of this review. The specific contribution of this review is threefold: (i) a mechanics-oriented classification of hierarchical and fractal-inspired architectures according to the deformation mechanism they activate (bending-, stretching-, membrane-, or buckling-dominated), rather than by geometric appearance alone; (ii) an explicit structure-mechanism-property-function framework linking multiscale geometry to strength, failure evolution, and energy absorption, tested against automotive crashworthiness as an application case study; and (iii) a critical account of when fractal–mathematical descriptors (scale invariance, similarity ratio, iteration depth, and fractal dimension) are mechanically meaningful, since many finite hierarchical lattices are fractal-inspired rather than fractal in the strict mathematical sense. The synthesis shows that relative density alone is an insufficient performance descriptor: outcomes depend on whether deformation is bending-, stretching-, membrane-, or buckling-dominated, and hierarchy or fractal-inspired recursion improves performance only when each structural level is assigned a distinct mechanical role rather than repeating geometry without function. The crashworthiness case study confirms that no single architecture is universally optimal once force efficiency, intrusion control, and manufacturability are considered alongside energy absorption. Future progress requires integrated structure-mechanism-property-function frameworks that combine theoretical modeling, high-resolution simulation, data-driven design, and experimental validation, with complexity justified only when it is mechanically purposeful, validated, and manufacturable at scale. Full article

Double-column reinforced-concrete (RC) hollow bridge piers are often assessed using flexure-dominated models, although their thin walls can develop shear-related deterioration. This study reanalyzes seven previously reported cyclic tests on scaled square hollow-pier columns and extends the assessment to a full-scale double-column system in OpenSees. The tests varied the shear-span ratio and transverse and longitudinal reinforcement. A flexure-only fiber model and an axial–flexure–shear interaction membrane–beam–truss element model (AFSI-MBTEM) were evaluated using six response indicators before cyclic and nonlinear time-history analyses of the prototype system. Lower shear-span ratios increased resistance but intensified inclined cracking, stiffness loss, and post-peak deterioration; increasing L/D from 3.9 to 7.9 reduced peak strength from 320.5 to 145.9 kN. AFSI-MBTEM reduced the mean absolute errors in peak strength, yield displacement, and effective stiffness to 3.08%, 11.83%, and 12.86%, respectively, but did not improve residual-displacement or mean hysteretic-loop-energy predictions. At the system level, shear-span ratio most strongly affected cyclic stiffness and peak base shear; wall-thickness ratio, width-to-depth ratio, and longitudinal reinforcement were also influential. Under three near-fault records, AFSI-MBTEM predicted 5.31–10.32% lower peak base shear, while displacement changes remained record-dependent. Shear-sensitive modeling improves force and deformation assessment, but the system-level trends remain conditional on the adopted prototype, parameter ranges, and records. Full article

This study presents the innovative design and development of biomimetic origami-based soft robotic grippers capable of two-stage grasping. Inspired by the biological structure of the sea urchin mouth, which combines external rigid teeth with an internal soft membrane, the proposed grippers employ origami architectures to achieve coordinated two-stage grasping. Novel waterbomb and Miura-ori origami architectures were introduced, enabling the formation of external and internal teeth. The developed grippers integrate an elastomeric membrane with an internal origami structure that enables contraction-driven folding under negative-pressure actuation. Multiple gripper configurations with varying dimensions are fabricated using paper and polymer-laminated paper skeletons. An energy-based modeling framework is introduced to describe the pressure–force relationship while accounting for the effects of structural deformation. Experimental evaluations conducted at different negative-pressure values quantified grasping performance and holding force. Imprint-based analysis confirmed the two-stage grasping mechanism, while grasping capability investigations demonstrated compliant interaction with delicate objects. Holding forces were measured using cylindrical metal and spherical wooden test objects of varying sizes and orientations. The waterbomb-based gripper achieved the most consistent performance, particularly for cylindrical objects, reaching a maximum holding force of 70 N, whereas the Miura-ori provided improved adaptability and higher holding forces for spherical objects, reaching 74.8 N, and maximum force-to-weight ratios of 327.2 and 346.6 were achieved for the waterbomb- and Miura-ori-based grippers, respectively. Full article

Oscillating water column (OWC) wave energy converters equipped with dielectric elastomer generators (DEGs) represent a promising technology for harnessing ocean wave energy. This study emphasises the critical role of functional specifications in guiding the development of these devices from initial concept to full-scale deployment. A comprehensive analysis of key design parameters that influence the performance and efficiency of flexible OWCs with DEG-based power take-off systems is presented. This investigation focuses on the effects of draft, membrane diameter, deformation characteristics, number of layers, and membrane thickness on power output. Utilising a combination of analytical tools, including Wave Venture software, MATLAB, and Abaqus, detailed simulations and analyses are conducted to optimise these parameters. Our results demonstrate that increasing the DEG diameter significantly enhances power output, with diameters between 5 and 12 m showing optimal efficiency. A critical strain threshold of approximately 32% is identified, beyond which power output efficiency diminishes. Furthermore, the study reveals that multi-layer DEG configurations can substantially increase energy production, with thinner membranes generally yielding higher outputs. These findings provide valuable insights for developing functional specifications that balance performance, manufacturability, and long-term reliability in marine environments. This research advances OWC technology by offering a parameter-screening framework to guide device design towards optimised configurations and to accelerate the path to commercial viability in the wave energy sector. Full article

Background/Objectives: Tuberculosis (TB), caused by Mycobacterium tuberculosis complex, remains a major global health challenge. Recently, D-enantiomer of human lactoferricin 1–11 (D-form hLF 1–11), a short peptide derived from the N-terminal region of lactoferrin, has demonstrated potent antimycobacterial activity. However, its direct mechanism of action has not yet been elucidated. Methods & Results: In the present study, M. smegmatis was employed as a model organism to investigate the mechanism underlying D-form hLF 1–11 activity. Initially, the minimum inhibitory concentration (MIC) was determined and the results revealed growth inhibition at 400 µg/mL. Live/dead fluorescence staining demonstrated mycobactericidal activity, as indicated by increased propidium iodide (PI) uptake relative to the untreated control. Scanning electron microscopy and high-resolution fluorescence microscopy revealed membrane disruption and substantial morphological deformation, along with a time-dependent accumulation of the peptide at the membrane and inside the cells. Furthermore, label-free quantitative proteomic analysis of peptide-treated cells revealed extensive metabolic alterations in carbon metabolism, acetyl-CoA-dependent lipid biosynthesis, oxidative stress defense, translational machinery, and energy production systems. Conclusions: Collectively, these findings provide mechanistic insights into the antimycobacterial activity of D-form hLF 1–11 against M. smegmatis. Full article

Cold bending provides a cost-effective method for fabricating triangular glass units for free-form architectural envelopes. Replacing conventional continuous edge constraints with discrete point clamps reduces over-constraint but introduces pronounced bending–membrane coupling in the unsupported spans between adjacent clamps. Consequently, the mechanisms governing local instability and optical-quality degradation remain insufficiently understood. In this study, cold-bending tests were performed on isosceles triangular fully toughened glass plates to measure out-of-plane deflection and surface-strain evolution. The experimental data were then used to establish and validate an Abaqus finite element model for systematic parametric analysis. Based on von Kármán’s large-deflection theory, a semi-empirical reduced-order framework that combines modal superposition with the response-surface method was developed to identify instability-sensitive configurations. The results show that, under weak constraints and large vertex angles, the panel response changes from a bending-dominated regime to a strongly nonlinear large-deflection regime governed by membrane effects; this transition is marked by a reversal of mid-span deflection and a compressive-to-tensile stress transition. Increasing the number of clamps from two to four substantially suppresses both global and local distortion by shortening the free spans and redistributing membrane strain energy, reducing peak mid-span deflection by 47–68%, and satisfying the EN 12150-1 limits for both bow deformation and local distortion. The height-to-base ratio is the dominant geometric parameter controlling instability. Under two-point support, a critical response turning point occurs at a height–base ratio of approximately 0.5 before the material fracture limit is reached, defining a geometric boundary below which optical serviceability failure accelerates. These findings provide a theoretical basis and quantitative engineering guidance for optimizing the cold-bending process of isosceles triangular fully toughened glass plates. Full article

Two spectrin-sensitive relaxations have been reported in the RBC plasma membrane: β_s (1.4 MHz, related to the interface β-relaxation) and γ1_s (9 MHz, rotation alignment of spectrin-bound dipoles by penetrating electric field). Here, a third (α_s) relaxation type is reported within the frequency region of surface (α) relaxation. With low-ion-strength outside media, the adsorption of blood plasma immunoglobulins on RBCs was found to inhibit β_s and γ1_s relaxations, while α_s relaxation was enforced with strong inflammation. The three relaxations are represented by three consecutive segments on the Cole′s plots: Δε_rd″.ω against Δε_r′ and Δε_rd″/ω against Δε_r′. Here, ω is the frequency of the field and Δε_r* = Δε_r′ + j.Δε_rd″ is the change in the relative complex dielectric permittivity of RBC suspension at the denaturation temperature of spectrin. The β_s segment in Δε_rd″.ω against the Δε_r′ plot could be regarded as a vector (complex number) whose projection on the vertical axis (the irreversible loss in energy) could express the ability of the plasma membrane to deform (under the impact of shear stress). Full article

Efficient energy harvesting from open-channel flows offers a sustainable solution for powering distributed sensing systems in water infrastructure. This study investigates a piezoelectric wake-excited membrane vortex-induced vibration (VIV) energy harvester through a combined numerical and mechanical approach. The device features an upstream cylindrical bluff body that generates a periodic vortex street, exciting a downstream flexible membrane equipped with surface-mounted piezoelectric patches. A one-way coupled CFD–FEM framework implemented in ANSYS was employed to assess the effects of membrane length, material stiffness, and flow conditions on hydrodynamic loading, structural deformation, and deformation power. Results show that membrane length mainly affects oscillation amplitude and force levels, whereas material stiffness has a stronger influence on membrane deformation and RMS mechanical power. Among the investigated materials, low-stiffness polyethylene yields the highest deformation power, while none of the analysed configurations reaches a full lock-in condition within the explored parameter range. Complementary mechanical analysis revealed that the stiffness of commercial piezoelectric patches significantly reduces local strain, thereby constraining the practically harvestable energy in the present baseline configuration. Spectral power density analysis identified the dominant shedding frequency and its harmonics, confirming that the flow response is governed by a coherent periodic excitation. These findings highlight key design trade-offs in wake-excited membrane harvesters and provide useful guidance for the future optimisation of self-powered hydraulic monitoring systems. Full article

Electrophysiology, mechanobiology, and the study of soft matter within cells demonstrate increasing amounts of evidence that neuronal signaling arises from interactions between membrane potential, force, and phase. Herein, we have attempted to collect and organize the evidence for each of these areas of study into an approximate structure called the electromechanical connectome: a three-way state–space (membrane potentials, nanoscale mechanical forces, and cytoplasmic rheology, including phase-separated liquid–liquid droplets) where membrane potentials, nanoscale mechanical forces, and cytoplasmic rheology, and phase-separated liquid–liquid droplets are likely to influence one another, influencing synaptic processing, plasticity and network stability. We will also attempt to illustrate the following: how changes in electrostatic fields can be used to alter the arrangement of lipids, hydration, and dielectric microdomains, and the contact geometry between organelles and activity dependent transcription; how mechanical dynamics associated with spines, axons, and the active zone of synapses may be used to modify the energy landscape of channels, the docking and priming of vesicles, and the transport of cytoskeletons; and how viscosity corridors, along with phase-separated micro-reactors, can be used to regulate the kinetics of signaling, molecular trafficking and metabolic processes in local environments. With these connections in mind, we will propose a multiphysical attractor model in which cognition is the result of navigating through metastable manifolds, while neurodegenerative disease may be a result of the progressive loss of electromechanical coherence, phase boundary control and energetic flexibility. Finally, we will present testable hypotheses and use AI-enabled digital twin methods to potentially quantify the early deformation of manifolds and provide precision biomarkers and therapeutic options. Full article

Hydrogen energy is vital for a clean, low-carbon society, and proton exchange membrane fuel cells (PEMFCs) represent a core technology for the conversion of hydrogen chemical energy into electrical energy. When PEMFC single cells are stacked under assembly force for high power output, their porous electrodes (gas diffusion layers, GDLs; catalyst layers, CLs) undergo compressive deformation, altering internal transport processes and affecting cell performance. However, existing microscale studies on PEMFC porous electrodes insufficiently consider compression (especially in CLs) and have limitations in obtaining compressed microstructures. This study proposes a combined framework from a microstructure perspective. It integrates the finite element method (FEM) with computational fluid dynamics (CFD). It reconstructs microstructures of GDL, CL, and GDL-bipolar plate (BP) interface. FEM simulates elastic compressive deformation, and CFD calculates transport properties (solid zone: heat/charge conduction via Laplace equation; fluid zone: gas diffusion/liquid permeation via Fick’s/Darcy’s law). Validation shows simulated stress–strain curves and transport coefficients match experimental data. Under 2.5 MPa, GDL’s gas diffusivity drops 16.5%, permeability 58.8%, while conductivity rises 2.9-fold; CL compaction increases gas resistance but facilitates electron/proton conduction. This framework effectively investigates compression-induced transport property changes in PEMFC porous electrodes. Full article

Calcium (Ca²⁺) is a signal messenger for ion flow in and out of microbial, parasitic, and host defense cells. Manipulation of calcium ion signaling with ion blockers and calcineurin inhibitors may improve host defense while decreasing microbial/parasitic resistance to therapy. Ca²⁺ release from intracellular storage sites controls many host defense functions (cell integrity, movement, and growth). The transformation of phospholipids in the erythrocyte membrane is associated with changes in deformability. This type of lipid bilayer defense mechanism helps to prevent attack by Plasmodium. Patients with sickle cell disease (SS hemoglobin) do not have this protection and are extremely vulnerable to massive hemolysis from parasitic infestation. Patients with thalassemia major also lack parasite protection. Alteration of Ca²⁺ ion channels responsive to environmental stimuli (transient receptor potential) results in erythrocyte protection from Plasmodium. Similarly, calcineurin inhibitors (cyclosporine) reduce heart and brain inflammation injury with Trypanosoma and Taenia. Ca²⁺ channel blockers interfere with malarial life cycles. Several species of parasites are known to invade hepatocytes: Plasmodium, Echinococcus, Schistosoma, Taenia, and Toxoplasma. Ligand-specific membrane channel constituents (inositol triphosphate and sphingosine phospholipid) constitute membrane surface signal messengers. Plasmodium requires Ca²⁺ for energy to grow and to occupy red blood cells. A cascade of signals proceeds from Ca²⁺ to two proteins: calmodulin and calcineurin. Inhibitors of calmodulin were found to blunt the population growth of Plasmodium. An inhibitor of calcineurin (cyclosporine) was found to retard population growth of both Plasmodium and Schistosoma. Calcineurin also controls sensitivity and resistance to antibiotics. After exposure to cyclosporine, the liver directs Ca²⁺ ions into storage sites in the endoplasmic reticulum and mitochondria. Storage of large amounts of Ca²⁺ would be useful if pathogens began to occupy both red blood cells and liver cells. We present scientific evidence supporting the benefits of calcium channel blockers and calcineurin inhibitors to potentiate current antiparasitic therapies. Full article

Background/Objectives Plant lectins have emerged as potential antifungal molecules, where the carbohydrate recognition domain (CRD) is possibly the main mode of action of these proteins. Previously, we saw that the lectin extracted from the seeds of Dioclea violacea (DVL) has anti-candida activity against Candida krusei cells by acting to inhibit ergosterol biosynthesis, cell wall deformation, and deregulation of the redox system. Methods We have now confirmed this anti-candida activity by proteomic analysis, with the expression of proteins that show us how C. krusei cells respond to this treatment. Results A total of 395 proteins were identified: 142 proteins exclusively found in untreated C. krusei cells and 245 proteins exclusive to DVL-treated cells. Eight proteins were detected in both conditions. Six displayed positive accumulation (fold change > 1.5), one exhibited negative accumulation (fold change < 0.5). We observed the expression of proteins related to cell wall remodeling; alteration of energy metabolism, suggesting a metabolic adaptation to stress; oxidative stress was responded to through the expression of proteins with antioxidant action, in addition to identifying multidrug transport proteins that are often involved in the process of antifungal resistance and sterol transport to the membrane. Conclusions Our results show the complexity of adaptive responses of C. krusei cells to treatment with DVL, elucidating new mechanisms of resistance and paving the way for the development of more effective and innovative antifungal therapies. Full article

Compact and efficient absorption refrigeration systems can effectively utilize waste heat and renewable energy when operated in a boiling-desorption mode, which maximizes the desorption rate. Hydrophobic membranes play a critical role in microchannel membrane-based generators; however, limited research has addressed bubble cross-membrane removal dynamics under boiling-desorption conditions, particularly the influence of membrane hydrophobicity. In this study, a two-phase flow bubble-removal model was developed to accurately represent boiling-desorption behavior. Numerical simulations were performed to investigate the effects of membrane hydrophobicity and heating power on bubble dynamics, wall temperature, venting rate, and channel pressure drop. Results show that bubble venting proceeds through four stages: nucleation and growth, liquid-film rupture with deformation, lateral spreading, and sustained vapor removal. Hydrophobicity effects become most significant from the third stage onwards. Increased hydrophobicity reduces wall temperature, with greater reductions at higher heat fluxes, and enhances venting performance by increasing total vapor removal and reducing removal time. Channel pressure fluctuations comprise high-frequency components from bubble growth and low-frequency components from venting-induced flow interruptions, with relative contributions dependent on hydrophobicity and heat flux. These findings provide new insights into bubble-removal mechanisms and offer guidance for the design and optimization of high-performance microchannel membrane-based generators. Full article

Laminated glass (LG) composite systems are increasingly being utilized in architectural and security applications due to their enhanced strength and safety features. Understanding the structural response of LG systems is crucial for optimizing their performance under blast loads. This paper presents a comprehensive study of an analytical model for predicting the static and dynamic resistance functions of various LG systems used in blast-resistant designs to advance engineering analysis and design methods. The proposed analytical model integrates the strain-rate-dependent interlayer behavior with the glass dynamic increase factors to generate a physically consistent post-fracture membrane resistance, offering a unified framework for deriving the static and dynamic resistance functions directly applicable to single-degree-of-freedom (SDOF) analyses across different LG layups. The developed models were validated statistically using full-scale water chamber results and dynamically against experimental blast field data and the results from shock tube testing. We validated the model’s accuracy for various LG layup configurations, including variations in the glass and interlayer sizes, types, and thicknesses. The established dynamic resistance model was developed by incorporating a strain-rate-dependent interlayer material model. The energy absorption of LG panels, influenced by factors like interlayer thickness and type, is critical for blast design, as it determines the panels’ ability to withstand and dissipate energy, thereby reducing the transmitted forces and deformations to a building’s structure. The dynamic model closely matched the dynamic deflection time histories, with a maximum difference of 6% for all the blast experiments. The static resistance validations across the various LG configurations consistently demonstrated reliable prediction results. The energy absorption comparisons between the analytical and quasi-static LG panel responses ranged from 1% to 17%. These advancements provide higher-fidelity SDOF predictions and clear guidance for selecting the interlayer type and thickness to optimize energy absorption. This will result in enhanced blast resistance and contribute to more effective blast mitigation in glazing system design. Full article