Anisotropic Nature Research Articles

Extrinsic and intrinsic determinants of thermal conductivity in mycelium composites

The need for the construction industry to reduce both operational and embodied carbon emissions is urgent. Traditional insulation materials, while effective, require energy-intensive processes and non-renewable resources, making them unsustainable. Mycelium-based composites (MBCs) offer a sustainable alternative with low embodied carbon, biodegradability, and non-toxicity, and studies show promising thermal performance. However, accurate measurement of λ is crucial to ensure effectiveness, requiring an understanding of the factors influencing these measurements. This paper reviews the thermal conductivity of MBCs, covering 19 studies reporting λ values from 0.026 W/mK to 0.18 W/mK. Measurement techniques and their uncertainties are reviewed, as well as additional factors affecting λ, including moisture content, density, temperature, substrate, fungal species, and growth conditions. The influence of the fungal-skin layer and the anisotropic nature of MBCs is discussed. Standardised measurement protocols and thorough methodological reporting are emphasised to ensure comparability. By optimising intrinsic parameters like species-substrate combinations and growth conditions, MBC thermal performance can be improved. This paper informs on MBC thermal characterization, promoting broader adoption in the construction industry and advancing sustainable practices. Consequently, this review aims to guide future research and applications, aiding in reducing both operational and embodied carbon emissions.

Interplay of Spin Nernst Effect and Entanglement Negativity in Layered Ferrimagnets: A Study via Exact Diagonalization

In this paper, we analyzed the influence of the spin Nernst effect on quantum correlation in a layered ferrimagnetic model. In the study of three-dimensional ferrimagnets, the focus is on materials with a specific arrangement of spins, where the neighboring spins are parallel and the others are antiparallel. The anisotropic nature of these materials means that the interactions between spins depend on their relative orientations in different directions. We analyzed the effect of magnon bands induced by the coupling parameters on entanglement negativity. The influence of the coupling parameters of the topologic phase transition on quantum entanglement is investigated as well. Numerical simulations using the Lanczos algorithm and exact diagonalization for different lattice sizes are compared with the results of spin wave theory.

A First‐Principles Study of Structural, Elastic, Mechanical, Thermodynamic, and Electronic Properties of Rb2XIO6 (X = Ga, In) Double Perovskites

Double perovskites (DPs) have gained the interest of researchers due to their unique properties. In present work, structural, mechanical, electronic, and thermodynamic properties of Rb2XIO6 (X = Ga, In) DPs are investigated using first‐principles calculations. The tolerance and octahedral factors are calculated in the allowed range of DPs. The phonons dispersion curves were computed with positive frequencies. The elastic constants prove the mechanical stability. Mechanical properties explore the anisotropic, brittle, and stiffer nature of both DPs. The computed band structures discover the metallic nature, where O–p and I–s states are found to cross the Fermi level. Debye temperature for Rb2GaIO6 is calculated higher than Rb2InIO6. Grüneisen parameter is evaluated to decrease with increasing pressure and temperature. Specific heat capacity is observed to saturate at 450 K. The coefficient of thermal expansion are calculated as 9 10−5 and 8.95 10−5 K−1 at 1000 K for Rb2GaIO6 and Rb2InIO6, respectively.

First-principles pressure-dependent investigation of the physical and superconducting properties of ThCr 2 Si 2 -type superconductors SrPd 2 X 2 (X = P, As)

The physical and superconducting characteristics of SrPd 2 P 2 and SrPd 2 As 2 compounds with applied pressure were calculated using density functional theory. The pressure effect on the structural properties of these compounds was investigated. The results show that both lattice constants and volume decrease almost linearly with increasing pressure. The elastic constants ( C ij ) for both compounds increase with increasing pressure and satisfy Born criteria for mechanical stability. The elastic parameters indicate the ductile behaviour and anisotropic nature of these compounds under applied pressure. The Debye temperature ( ϴ D ) and melting temperature ( T m ) increase with increasing pressure. The electronic band structure calculation of both compounds exhibits metallic characteristics at different pressures. The density of electronic states at the Fermi level, N ( E F ), consistently decreases as pressure increases, which is also reflected in the repulsive Coulomb pseudopotential ( µ* ), and the electron–phonon coupling constant ( λ ). These optical features suggest that both compounds are suitable for optoelectronic device applications. Furthermore, the superconducting transition temperature, T c , for both compounds is predicted to vary with applied pressure due to changes in ϴ D , N ( E F ) , µ* and λ .

Analyzing heat transfer performance of ARCH lattice microchannel heat exchanger fabricated using selective laser melting

Lattice structures are emerging as highly effective heat exchange mediums in exchangers and radiators due to their low weight, high specific stiffness and strength, and extensive surface area. These attributes render them particularly suitable for enhancing heat transfer efficiency while maintaining a lightweight and structurally sound design. Certain applications, such as hot stamping, demand both high heat transfer performance and significant load-bearing capacity. Arch micro-strut (ARCH) lattice is a kind of high load-bearing lattice. Currently, there is a gap in the research on its heat transfer performance. This study provides a comprehensive analysis of the heat transfer and mechanical performance of additively manufactured ARCH lattice structures. Deionized water (DI water) was selected as the working fluid in this study. The analysis spans various relative densities, inlet velocities, array orientations, and gradient configurations, employing both experimental and simulation approaches. The results of this study reveal that as relative density increases, the pressure drop gradually rises, while the convective heat transfer coefficient increases before stabilizing. The pressure drop reaches a maximum of 348 kPa at 4 m/s, 40 % relative density, and the convective heat transfer coefficient reaches a maximum of 13,805 W/m2·k at 4 m/s, 20 % relative density. At a relative density of 20 %, the convective heat transfer coefficient reaches its maximum at the same inlet velocity. Specifically, at an inlet velocity of 4 m/s, the convective heat transfer coefficient for a 20 % relative density is 115 % higher than that at 0 %. The maximum Von Mises stress and deformation decrease progressively as relative density increases, from 980.72 MPa to 236.05 MPa, suggesting a substantial enhancement in the compressive properties of the structure. Additionally, a higher inlet velocity results in an enhanced convective heat transfer coefficient. The convective heat transfer coefficient increased by an average of 2300 W/m2·k when the flow rate increased from 1 m/s to 4 m/s. The anisotropic nature of ARCH lattice structure significantly affects mechanical properties and heat transfer efficiency, with the heat transfer coefficient being higher at the inlet along X-direction compared to Z-direction, and a lower pressure drop in X-direction. The gradient structure is shown to effectively address the non-uniform heat dissipation requirements of various components. Specifically, decreasing gradient (DG) configuration offers superior heat transfer performance under similar pressure drop conditions, while increasing gradient (IG) configuration provides better temperature uniformity. Overall, ARCH lattice structure demonstrates superior performance compared to face-centered cubic with vertical strut (FCCZ) structure, with an efficiency index approximately 200 % higher than that of FCCZ structure.

Defect Self-Elimination in Nanocube Superlattices Through the Interplay of Brownian, van der Waals, and Ligand-Based Forces and Torques.

Understanding defect healing is necessary to control the electronic and optoelectronic performance of devices based on nanoparticle (NP) superlattices. However, a key challenge remains to understand how NP interactions and the resulting dynamics are coupled to defect self-elimination during assembly processes. Additional degrees of freedom that account for the anisotropic nature of NPs associated with rotational dynamics and torques further complicate the challenge. Here, we investigate nanocube (NC) superlattices by employing liquid-phase transmission electron microscopy, continuum theory, and molecular dynamics simulations. Our detailed analyses reveal that interparticle forces and torques due to ligand interactions dominate those from Brownian motions and van der Waals interactions. More importantly, NC translations and rotations induced by unbalanced forces and torques are transmitted to neighboring NCs, prompting "chain interactions" in a two-dimensional (2D) network and expediting self-elimination. The mechanistic understanding will further enable the design and fabrication of defect-free superlattices as well as those with tailored defects via assembly of anisotropic particles.

Linear and nonlinear ultrasound parameters attributed to anisotropy in granite

The anisotropic nature of granite, a key factor affecting its mechanical properties, is inherently governed by its mineral alignment and the presence of orthogonal cleavage planes: rift, grain, and hardway. This study examines how these cleavage planes influence anisotropy, particularly in the context of microcracking formation and acoustic properties. A new measurement procedure for the acoustic nonlinearity parameter (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document}) is developed to address the well-known limitations of conventional linear ultrasound methods, including wave velocity and attenuation coefficient, in detecting microstructural changes induced by existing cleavage planes. Unlike other parameters, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document} exhibits remarkable changes depending on the plane type, highlighting its high sensitivity to the mineral distribution in each cleavage plane and to the microcracks. A correlation between the linear and nonlinear parameters provides further evidence of the superiority of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document} in detecting inherent microscale defects that develop in each plane and affect the anisotropic characteristics of granite. The findings of this study confirm that nonlinear ultrasound is capable of elucidating the mechanisms underlying the origin of anisotropy in granite due to microcracks, with broader implications for understanding unidentified chemical and mechanical phenomena in geological materials.

2D Multifunctional Phototransistor Based on MoTe2/Graphene/SnS0.25Se0.75 Heterostructure with High Photogain and Reconfigurable Polarized Detection

Abstract2D van der Waals (vdWs) heterojunctions exhibit facile fabrication process and tunable optoelectronic properties. However, suppressing interfacial charge traps and multifunctional photoresponse remain significant challenges. Here, the study designs a 2D multifunctional phototransistor based on ambipolar MoTe2/graphene (Gr)/p‐type SnS0.25Se0.75 double vdWs vertical heterostructure via alloy engineering. The middle Gr interlayer is pivotal in reducing interfacial charge traps, facilitating vertical photocarrier transportation, and enhancing light absorption coefficient. Under photogating effect, the trapped electrons in SnS0.25Se0.75 promote the photogating effect, resulting in the maximum photogain of 8084 and specific detectivity (D*) of 8.2 × 1012 Jones. Under photoconductive effect, a high responsivity (R) of 36.9 A W−1 and D* of 7.17 × 1011 Jones are achieved. Under photovoltaic effect, the devices exhibit a remarkable R of 501 mA W−1, D* of 1.4 × 1011 Jones. Notably, a self‐driven photocurrent polarized ratio of 8 under 635 nm is achieved because of the anisotropic nature of SnS0.25Se0.75 and the effective double built‐in electric fields. By varying the gate voltage, the polarization ratio can be modulated from 1 to 2.5, enabling reconfigurable polarized‐sensitive detection. Above all, the designed heterojunction with multifunctional and reconfigurable polarization detection.

Numerical investigation of the effective mechanical properties of architected structures: a comparative study of flexural stiffness, homogenization, and elastic anisotropy

Abstract The mechanical behavior of architected structures is influenced by various parameters, including the topology of their unit cells. This anisotropic nature requires the determination of the mechanical properties under different loading scenarios. This study employs numerical investigation to characterize the influence of topology on the mechanical properties of eight architected structures, focusing on effective elastic properties and anisotropic elastic behavior. The analyzed topologies encompass four based on struts (lattices) and four based on triply periodic minimal surfaces (TPMS), comprising Sheet and Network phases. Initially, beams composed of architected structures are subjected to flexure, with Euler–Bernoulli and Tymoshenko’s theories utilized in a first numerical approach to determine their effective properties. Subsequently, a numerical homogenization method along with the Voigt-Reuss-Hill scheme is employed in a second approach. A more substantial influence of topology on the effective properties is observed in low relative densities. The study revealed that for a relative density of 10%, the appropriate selection of the topology increases the stiffness of a structure by up to ∼126%. The EBT approach underestimated the stiffness by up to ∼26% due to neglecting the impact of shear on beam deflection. The tensorial anisotropy index revealed up to ∼27% higher anisotropy compared to the Zener index. These findings provide a valuable numerical tool for the comparison and selection of architected structures suitable for diverse applications.

Electrochemical identification and quantification of through-plane proton channels in graphene oxide membranes.

Stacked graphene oxide (GO) proton membranes are promising candidates for use in energy devices due to their proton conductivity. Identification of through-plane channels in these membranes is critical but challenging due to their anisotropic nature. Here, we present an electrochemical reduction method for identifying and quantifying through-plane proton channels in GO membranes. The simplicity lies in the operando optical observation of the change in contrast as GO is electrochemically reduced. Here, we find three proton-dominated three-phase interfaces, which are critical for the reduction reactions of GO membranes. Based on these findings, a method is proposed to identify and quantify through-plane channels in stacked GO proton membranes using a simple three-electrode device in combination with real-time imaging of the membrane surface.

A BIONIC-INSPIRED DRAGONFLY ALGORITHM FOR PARAMETRIC OPTIMIZATION AND DAMAGE INVESTIGATION DURING MACHINING OF MODIFIED POLYMER NANOCOMPOSITE

Polymer nanocomposite is commonly used to develop structural components of space, aircraft, biomedical, sensor, automobile, and battery sector applications. It remarkably substitutes the heavyweight metallic and nonmetallic engineering materials. The machining principles of polymer nanocomposites are intensely different and complex from traditional metals and alloys. The nonhomogeneity, abrasive, and anisotropic nature differs its machining aspect from conventional metallic materials. This investigation aims to execute the CNC drilling of modified nanocomposite using Graphene–carbon (G-C) @ epoxy matrix. The process constraints, namely, cutting speed (S), feed (F), and wt.% of graphene oxide (GO) vary up to three levels and are designed according to the response surface methodology (RSM) array. The nonlinear model is created to predict surface roughness (Ra) and delamination (Fd) on regression analysis. It has been found that the average error for Ra is 0.94% and for Fd it is 3.27%, which is acceptable in model predictions. The metaheuristics-based evolutionary Dragonfly algorithm (DA) evaluated the optimal parametric condition. The optimal setting prediction for the DA is observed as cutting speed (S)-37.68[Formula: see text]m/min, feed (F)-80[Formula: see text]mm/min, and wt.% of graphene oxide (GO)-1%. This algorithm demonstrates a higher application potential than the previous efforts in controlling Ra and Fd values. Both the drilling response values are found to be minimized when the cutting speed increases and the feed decreases. The best fitness value for the DA is 1.626 for surface roughness and 5.086 for delamination. This study agreed with the prediction model’s outcomes and the process parameters’ optimal condition. The defects generated during the sample drilling, such as fiber pull out, uncut/burr, and fiber breakage, were examined using FE-SEM analysis. The optimal findings of the DA module significantly controlled the damages during machining.

Optimizing kerf quality in high-speed WEDM of thin woven CFRP composites: a taguchi, WASPAS, and PSO approach

The process of machining CFRP composites presents unique challenges, particularly in the context of WEDM. The inherent properties of CFRP composites, such as their low electrical conductivity, anisotropic nature, and heterogeneous composition, require further research to enhance their machinability through WEDM techniques. This study examines the enhancement of kerf characteristics such as kerf width (Wk), delamination factor (DFK), and cutting speed (CSK) in thin woven 0°/90° CFRP composites using high-speed WEDM. A Taguchi L16 experimental analysis was employed to analyze the impact of key process parameters, including pulse-on (Pon), pulse-off (Poff), and input current (I), in conjunction with CFRP parameters such as the CFRP thickness (T) and cutting direction on the kerf characteristics. The CFRP thickness ranged from 0.5 to 2.0 mm, and the cutting directions studied were horizontal and inclined 30° cuts. A multiple-response optimization strategy using the CRITIC-WASPAS approach coupled with a particle swarm optimization (PSO) algorithm were applied to identify the ideal process combination for various CFRP thicknesses. The findings indicated that the CFRP thickness, pulse-off time, and input current are the most statistically significant factors influencing the overall kerf characteristics. The cutting direction has a negligible effect on the kerf width but has conflicting effects on the delamination factor and cutting speed. Specifically, a horizontal cut decreases delamination, whereas an inclined 30° cut is preferable for achieving higher cutting speeds. For precise kerf cutting, optimal process combinations were determined: Pon (30 µs), Poff (30 µs), and I (ranging from 4 to 5 A) for 0.5 mm CFRP thickness, and Pon (30 µs), Poff (15 µs), and varying input currents of 4 A, ranging from 4 to 3 A, and 3 A for CFRP thicknesses of 1.0, 1.5, and 2.0 mm, respectively.

The Abrasive Water Jet Cutting Process of Carbon-Fiber-Reinforced Polylactic Acid Samples Obtained by Additive Manufacturing: A Comparative Analysis

Carbon-fiber-reinforced polymer (CFRP) composites are widely used across industries due to their enhanced strength and stiffness properties. Fused deposition modeling (FDM) enables the cost-effective production of polymer samples, such as carbon-fiber-reinforced PLA (CFR-PLA). However, CFRP’s hardness and anisotropic nature present significant challenges in conventional machining, including rapid tool wear and thermal sensitivity. Consequently, abrasive water jet machining (AWJM) has proven to be an effective alternative for machining CFRP materials, offering benefits such as reduced tool wear, minimized thermal damage, and improved cutting quality. This study focuses on a comparative analysis of the effects of AWJM parameters on PLA and CFR-PLA samples, specifically to evaluate the influence of carbon fiber reinforcement on machining performance. The findings highlight the critical role of reinforcements in machining behavior. The results suggest that optimizing cutting parameters significantly reduces taper formation and improves machining accuracy. In particular, adjustments to process parameters resulted in lower taper angles and reduced surface roughness in the cutting zones of the CFR-PLA samples.

Catalytic Strategies Enabled Rapid Formation of Homogeneous and Mechanically Robust Inorganic‐Rich Cathode Electrolyte Interface for High‐Rate and High‐Stability Lithium‐Ion Batteries

AbstractLithium iron phosphate (LFP) cathode is renowned for high thermal stability and safety, making them a popular choice for lithium‐ion batteries. Nevertheless, on one hand, the fast charge/discharge capability is fundamentally constrained by low electrical conductivity and anisotropic nature of sluggish lithium ion (Li+) diffusion. On the other hand, the interface and internal structural degradation occurs when subjected to high‐rate condition. Herein, a multifunctional boron‐doping graphene/lithium carbonate (BG/LCO) nanointerfacial layer on surface of commercial LiFePO4 particles is designed, in which the BG layer catalyzes the rapid reaction of Li2CO3‐LiPF6 for homogeneous and mechanically robust inorganic LiF‐rich structure across the cathode‐electrolyte interphase (CEI), forms a conductive network to significantly enhance both electron and Li+ transport, and strengthens the FeO bonding to minimize both Fe loss and the formation of Fe‐Li antisite defects. Correspondingly, the modified LFP cathode achieves a high capability of 113.2 mAh g−1 at 10 C and extraordinary cyclic stability with 88.0% capacity retention over 1000 cycles as compared to the pristine LFP cathode with a capacity of only 94.0 mAh g−1 and 64.6% capacity retention. It also exhibits great enhancements of 20.1% and 3.7% at higher‐rate condition (room temperature/15 C) and the low temperature condition (−10 °C/1 C), respectively.

Computational study of micromagnetorotation on the micropolar flow characteristics in a rectangular channel with continuous applied shear

The aim of this investigation is to computationally analyse the effect of micromagnetorotation on flow characteristics within magneto-micropolar flows. To the authors' knowledge such consideration has not been discussed in the literature in present context. The assumption in literature that the magnetization is parallel to the applied magnetic field is incorrect due to the anisotropic nature of micropolar flows. This allows to re-investigate the micropolar flows in the present of micromagnetorotation. To this end, the theory of magneto-micropolar flows is briefly described and a computational model governing the system dynamics is presented. Finite element code in FreeFem++ is developed and validated through an exact solution. It turns out that the numerical findings obtained are in strong agreement with the analytical results. The results obtained are significant because they can assist researchers in allied fields of electronics, materials science and biomedical engineering in finding solutions to a variety of real-world issues.

New semiconducting K2MgSiH6 (H = Cl & Br) halides have been investigated via DFT approach; their mechanical, optical, and structural properties were studied in detail

Researchers are now avoiding perovskite materials containing lead due to their toxicity and instability in open air and heat. In this study, our research group worked on potassium-based K2MgSiCl6 & K2MgSiBr6 perovskite compounds and thoroughly investigated these materials’ basic behaviours. Goldschmidt and formation energy results certify the structure and thermodynamic stabilities of the studied compounds. The band gaps noted for the K2MgSiCl6 & K2MgSiBr6 perovskites were 2.42 eV & 1.88 eV, respectively. After the mechanical observations of the investigated compounds, it became apparent that both the studied compounds own brittle and anisotropic nature. Based on the tendency to absorb electromagnetic radiations both in the ultra-violet and visible range, it enables the K2MgSiCl6 & K2MgSiBr6 perovskites suitable for detectors, solar cells, and many other optoelectronic devices. The K2MgSiBr6 material showed the first response to the electromagnetic radiations in the visible range and acquired the optical conductivity value of 1219 (Ω.cm)-1; however, K2MgSiCl6 material showed its response to a bit higher energetic photons in the visible range than K2MgSiBr6 material, but its optical conductivity was higher (i.e., 1270 (Ω.cm)-1) than the K2MgSiBr6 material in the visible range.

Anisotropic Redox on Pristine Graphene

AbstractChemically modified graphene is an attractive electrode material for electrocatalysis, energy devices, and sensors, whereas pristine graphene is electrochemically passive. The remarkable anisotropic electrochemical nature of graphene is uncovered by π–π interaction, making pristine graphene more active than bare Au. The π–π stacking during redox reaction “dopes” the graphene, disrupting the passivating hydration layer, making it a facile electrochemical electrode. The structure during π–π stacking‐mediated redox of methylene blue (MB) is quantitatively measured by the differential reflectivity of a polarized laser on a ≈100 micron spot. The local redox reaction current varies over fourfold due to the orientation of the ≈10 micron size grains. The mosaic‐grain anisotropy on each spot shows local uniaxial orientation. The redox signal at the optimum orientation is over 2.5‐fold greater than that for bare Au on the same electrode. The redox signal is over fivefold greater at the edges of graphene compared bare Au. Remarkably, the π–π interaction increases chemical stability significantly, leading to negligible photo‐degradation at the approximate absorption wavelength of MB. The exclusive redox activity due to π–π interaction on pristine graphene adds to the toolbox of making exotic opto‐electrochemical electrode materials for electrocatalysis, sensing, and electronics.

Molecular permeation through large pore channels: computational approaches and insights.

Computational methods such as molecular dynamics (MD) have illuminated how single-atom ions permeate membrane channels and how selectivity among them is achieved. Much less is understood about molecular permeation through eukaryotic channels that mediate the flux of small molecules (e.g. connexins, pannexins, LRRC8s, CALHMs). Here we describe computational methods that have been profitably employed to explore the movements of molecules through wide pores, revealing mechanistic insights, guiding experiments, and suggesting testable hypotheses. This review illustrates MD techniques such as voltage-driven flux, potential of mean force, and mean first-passage-time calculations, as applied to molecular permeation through wide pores. These techniques have enabled detailed and quantitative modeling of molecular interactions and movement of permeants at the atomic level. We highlight novel contributors to the transit of molecules through these wide pathways. In particular, the flexibility and anisotropic nature of permeant molecules, coupled with the dynamics of pore-lining residues, lead to bespoke permeation dynamics. As more eukaryotic large-pore channel structures and functional data become available, these insights and approaches will be important for understanding the physical principles underlying molecular permeation and as guides for experimental design.

Enhancing horticultural harvest efficiency: The role of moisture content in ultrasonic cutting of tomato stems

Ultrasonic vibration has notable benefits in the harvesting and processing of tomato stems, particularly in reducing cutting force and minimizing moisture loss. Given the anisotropic nature of biological materials, the moisture content of tomato stems significantly impacts their physical properties. This study investigates the influence of varying moisture content on temperature and cutting force during the ultrasonic cutting of tomato stems. Initially, the moisture content of tomato stems at different maturity stages was measured using a water activity meter. Mechanical properties were characterized using a universal testing machine, and thermal properties were analyzed with a differential scanning calorimeter (DSC). Regression models were established to correlate moisture content with these material properties. Additionally, a three-dimensional microscopic model of stem skeletons, interfaces, and fiber bundles was created to simulate the fracture mechanisms during ultrasonic cutting under different moisture levels. Single-factor and response surface optimization experiments were conducted using a custom experimental setup under varying maturity stages, excitation frequencies, and voltage variations. Results showed that after 24 h, the peak temperatures for tomato stems at different maturity stages were 97.84 °C, 80.59 °C, and 74.15 °C, with corresponding cutting forces of 0.492 N, 0.544 N, and 0.998 N, respectively. The discrepancy between experimental results and simulation data was within 10 %. Higher moisture content was found to enhance the thermal conductivity of fiber materials, aiding in the fracture of fiber bundles, thus reducing cutting time and force. This study provides a theoretical foundation for the application of ultrasonic technology in the efficient harvesting and processing of industrial crops, with significant implications for horticultural crop treatment and processing.

Advanced Sensors and Sensing Systems for Structural Health Monitoring in Aerospace Composites

This review examines the state‐of‐the‐art sensors and sensing technologies employed for structural health monitoring (SHM) in aerospace composites, highlighting the shift from conventional nondestructive evaluation techniques to real‐time monitoring systems. The review discusses the challenges associated with composite materials, such as their anisotropic nature and susceptibility to invisible damage, and how these challenges have driven the improvement of SHM techniques. Fiber‐optic sensors, including interferometric, distributed, and grating‐based sensors, are analyzed for their high sensitivity and multiplexing capabilities, making them suitable for distributed sensing applications. Piezoelectric sensors are evaluated for their effectiveness in both active and passive damage detection methods. At the same time, piezoresistive self‐sensing systems are explored for their potential to integrate sensing directly into composite materials. The review also addresses the challenges encountered in implementing SHM systems. It suggests solutions like protective coatings, advanced data processing algorithms, and modular system design to overcome these challenges. In conclusion, this review provides a comprehensive overview of the current SHM technologies for aerospace composites, underscoring the need for sustained research and development to improve sensor technology, expand data processing capabilities, and ensure seamless integration with aircraft systems, thus contributing to the safety and efficiency of aerospace operations.