Microscale Flow Simulation of Resin in RTM Process for Optical Fiber-Embedded Composites.

By embedding optical fiber sensors into fiber preforms and utilizing liquid molding processes such as resin transfer molding (RTM), intelligent composite materials with self-sensing capabilities can be fabricated. In the liquid molding process of these intelligent composites, the quality of the final product is highly dependent on the resin flow and impregnation effects. The embedding of optical fibers can affect the microscopic flow and impregnation behavior of the resin; therefore, it is necessary to investigate the specific impact of optical fiber embedding on the resin flow and impregnation of fiber bundles.

A strain-programmed lignin-based Janus patch for rapid healing of postoperative rectal wounds.

Clinically, patients experience severe pain, frequent bleeding, and delayed wound healing after hemorrhoidectomy due to recurrent fecal contamination during postoperative dressing changes and bowel movements, which exacerbate wound irritation. : In this study, we developed a strain-programmed lignin-based multifunctional Janus patch (S-SFR@AGL) to accelerate rectal wound repair. This patch features a pre-stretched fluorinated silicone rubber side with robust anti-biofouling and strain-programmed properties, paired with a lignin-based hydrogel side offering potent antibacterial, antioxidant, bioadhesive, and hemostatic capabilities.

Molecular Dynamics Simulation of Hydrogen Permeation Behavior in Epoxy Resin Systems.

Liquid hydrogen (LH) storage using carbon-fiber-reinforced composite pressure vessels is facing increasing demands in aerospace engineering. However, hydrogen permeation in epoxy resin matrixes seriously jeopardizes the function and safety of the cryogenic vessels, and the micro-behavior of hydrogen permeation in epoxy resins remains mysterious. This study performed molecular dynamics (MD) simulations to investigate the hydrogen molecule permeation behaviors in two types of epoxy resin systems, with similar epoxy reins of bisphenol A diglycidyl ether (DGEBA) and different curing agents, i.

Recent advances and future prospects of flexible sensors based on natural rubber.

Sensors have been playing increasingly important roles in the fields of healthcare, environmental monitoring, transportation, and industrial automation. Flexible sensors have been developed to overcome the shortcomings of traditional rigid sensors, especially in the fields of wearable and implantable electronics and soft robotic applications. However, the elastic substrates of current flexible sensors are predominantly derived from petrochemical resources, which face challenges such as non-renewability and suboptimal performance.

Development of a deep neural network model for ultra-early neurological deterioration in ischemic stroke and analysis of associated risk factors.

Background: In this study, we established a deep neural network (DNN)-based predictive model, aiming to provide a basis for improving the treatment prognosis of early neurological deterioration (END) in patients with ultra-early ischemic stroke after intravenous thrombolysis with Alteplase.

Methods: A total of 1747 patients with ultra-early ischemic stroke who received intravenous thrombolysis with Alteplase were retrospectively included into the Yidu cloud database. These patients were assigned into the END group (234 cases) and the (No-END) group (1513 cases) based on whether END occurred within 48 h of admission.

Development and Recent Progress of Hoses for Cryogenic Liquid Transportation.

Recently, the application of cryogenic hoses in the field of cryogenic media has become a hot topic, especially in the industry of offshore liquefied natural gas and aerospace field. However, the structure of cryogenic hoses is complex, and reasonable structural properties are required due to the harsh working conditions. There is still plenty of scope for further development to improve the performance in all aspects.

Mechanistic study on the promotion of Ca leaching in steel slag through high-temperature solid waste modification.

Indirect carbonation of steel slag is an effective method for CO storage, reducing emissions, and promoting cleaner production in the steel industry. However, challenges remain, such as low Ca leaching rates and slag management complexities arising from variations in mineral compositions. To address this, a high-temperature modification process is proposed to alter the mineral composition and facilitate the synergistic utilization of calcium and iron.

Ultrasonic imaging of delamination in thick CFRP laminates using an energy-compensation reverse time migration method.

In ultrasonic reflection method, the precision of defect detection in thick carbon fiber reinforced plastics (CFRP) is compromised by acoustic energy attenuation. An energy-compensation reverse time migration (ECRTM) method is proposed to identify multiple defects accurately. Forward and backward wavefields are formed using the finite element method within an anisotropic acoustic model based on the Christoffel equation and Bond transformation.

An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets.

Coarse-grained modeling shows potential in exploring the thermo-mechanical behaviors of polymers applied in harsh conditions such as cryogenic environment, but its accuracy in simulating fracture behaviors of highly cross-linked epoxy thermosets is largely limited due to the complex molecular structures of the cross-linked networks. We address this fundamental problem by developing a CG modeling method where the backbones and electrostatic interaction (EI) contributions in the cross-linked networks are retained, and thus the potentials of the CG model can be directly extracted, or parametrized on the basis of, existing all-atomistic (AA) force fields. A multilevel parametrization procedure was adopted, where the bond potentials were parametrized relying on the results of density functional theory (DFT) simulation, whereas the nonbond potentials were parametrized by renormalizing the cohesive interaction strength.

Cryogenic Mechanical Properties and Stability of Polymer Films for Liquid Oxygen Hoses.

To select the appropriate polymer thin films for liquid oxygen composite hoses, the liquid oxygen compatibility and the cryogenic mechanical properties of four fluoropolymer films (PCTFE, ETFE, FEP and PFA) and two non-fluoropolymer films (PET and PI) before and after immersion in liquid oxygen for an extended time were investigated. The results indicated that the four fluoropolymers were compatible with liquid oxygen before and after immersion for 60 days, and the two non-fluoropolymers were not compatible with liquid oxygen. In addition, the cryogenic mechanical properties of these polymer films underwent changes with the immersion time, and the changes in the non-fluoropolymer films were more pronounced.

A review on guided-ultrasonic-wave-based structural health monitoring: From fundamental theory to machine learning techniques.

The development of structural health monitoring (SHM) techniques is of great importance to improve the structural efficiency and safety. With advantages of long propagation distances, high damage sensitivity, and economic feasibility, guided-ultrasonic-wave-based SHM is recognized as one of the most promising technologies for large-scale engineering structures. However, the propagation characteristics of guided ultrasonic waves in in-service engineering structures are highly complex, which results in difficulties in developing precise and efficient signal feature mining methods.

Electrothermally Self-Healing Delamination Cracks in Carbon/Epoxy Composites Using Sandwich and Tough Carbon Nanotube/Copolymer Interleaves.

Herein, two sandwich and porous interleaves composed of carbon nanotube (CNT) and poly(ethylene-co-methacrylic acid) (EMAA) are proposed, which can simultaneously toughen and self-heal the interlaminar interface of a carbon fiber-reinforced plastic (CFRP) by in situ electrical heating of the CNTs. The critical strain energy release rate modes I () and II () are measured to evaluate the toughening and self-healing efficiencies of the interleaves. The results show that compared to the baseline CFRP, the CNT-EMAA-CNT interleaf could increase the by 24.

Effects of early florfenicol exposure on glutathione signaling pathway and PPAR signaling pathway in chick liver.

Florfenicol (FFC) is a common antibiotic for animals. The nonstandard and excessive use of FFC can cause veterinary drug residues in animals, pollute soil and marine environment, and even threaten human health. Therefore, it is necessary to study the toxicity and side effects of FFC on animals.

Salvia miltiorrhiza polysaccharides alleviates florfenicol induced kidney injury in chicks via inhibiting oxidative stress and apoptosis.

Florfenicol (FFC) is a commonly used antibiotic in animal husbandry, which is easy to cause organs damage in a variety of animals. It has been proved to have nephrotoxicity and affect the yield and quality of meat products. Salvia miltiorrhiza polysaccharides (SMPs) have been proved to have the pharmacological effects of regulating immunity and protecting the liver of animals, and its alleviative effect on renal injury is unclear.

Multi-Mode Ultrasonic Guided Waves Based Damage Detection in L-Bars with Asymmetric Cross-Section with Sum of Multiple Signals Method.

Bars are significant load-carrying components in engineering structures. In particular, L-bars are typical structural components commonly used in truss structures and have typical irregular asymmetric cross-sections. To ensure the safety of load-carrying bars, much research has been done for non-destructive testing (NDT).

Ultra-fast charging in aluminum-ion batteries: electric double layers on active anode.

With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Here we report rechargeable aluminum-ion batteries capable of reaching a high specific capacity of 200 mAh g. When liquid metal is further used to lower the energy barrier from the anode, fastest charging rate of 10 C (duration of 0.

A Review of the Polymer for Cryogenic Application: Methods, Mechanisms and Perspectives.

Recently, the application of polymer-based composites at cryogenic conditions has become a hot topic, especially in aerospace fields. At cryogenic temperature, the polymer becomes more brittle, and the adverse effect of thermal stress induced by temperature is more remarkable. In this paper, the research development of thermoset and thermoplastic polymers for cryogenic applications are all reviewed.

Structural Damage Identification Based on Integrated Utilization of Inverse Finite Element Method and Pseudo-Excitation Approach.

The attempt to integrate the applications of conventional structural deformation reconstruction strategies and vibration-based damage identification methods is made in this study, where, more specifically, the inverse finite element method (iFEM) and pseudo-excitation approach (PE) are combined for the first time, to give rise to a novel structural health monitoring (SHM) framework showing various advantages, particularly in aspects of enhanced adaptability and robustness. As the key component of the method, the inverse finite element method (iFEM) enables precise reconstruction of vibration displacements based on measured dynamic strains, which, as compared to displacement measurement, is much more adaptable to existing on-board SHM systems in engineering practice. The PE, on the other hand, is applied subsequently, relying on the reconstructed displacements for the identification of structural damage.

Investigation of thermo-acoustoelastic guided waves by semi-analytical finite element method.

Guided waves are sensitive to variations in propagation environments. Many recent studies have focused on the uniform thermal effect on Lamb waves. However, there is little research on the thermal effect in a more complex situation, such as a nonuniform thermal effect and wave propagation in an arbitrary cross-section.

Environmental and operational conditions effects on Lamb wave based structural health monitoring systems: A review.

Lamb wave is widely recognized as one of the most encouraging tools for structural health monitoring (SHM) systems. In spite of many favourable characteristics of Lamb wave for SHM, real-world application of these systems is still quite limited. Beside the complexities derived from multi-modal, dispersive and multi-path characteristics of Lamb waves, one of the main challenges in Lamb wave based SHM is sensitivity of these systems to environmental and operational conditions (EOCs) parameters.

Molecular dynamics simulation on the formation and development of interlayer dislocations in bilayer graphene.

Molecular dynamics simulations are used to study the formation and development of interlayer dislocations in bilayer graphene (BLG) subjected to uniaxial tension. Two different BLGs are employed for the simulation: armchair (AC-BLG) and zigzag (ZZ-BLG). The atomic-level strains are calculated and the parameter 'dislocation intensity' is introduced to identify the dislocations.

Gate-Free Hydrogel-Graphene Transistors as Underwater Microphones.

A perfect impedance match from water-rich hydrogels to an oceanic background makes hydrogel microphones ideal for long-distance, underwater acoustic reception with zero reflection. A novel hydrogel-graphene transistor is thus designed to work under a gate-free mode, in which a sheet of graphene directly converts mechanical vibrations from a microstructured hydrogel into electrical current. This work shows that the quantum capacitance of graphene plays an important role in determining the shift of the Fermi level in graphene and subsequently the amplitude of the current signal.

Lamb waves and electro-mechanical impedance based damage detection using a mobile PZT transducer set.

Lamb waves and electro-mechanical impedance (EMI) based methods are increasingly used in damage detection owing to their high sensitivity to small structural defects. Lamb wave based methods are effective in detecting damages in a large area and electro-impedance based methods are suitable for characterizing the identified damage. Based on these two methods, a novel combined damage detection method is presented in this research.