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As a highly efficient and environmentally friendly gas fuel, hydrogen has emerged as one of the most promising sources of energy. However, the hydrogen explosion limit is low, the explosion risk is high, and the production, storage and transportation processes are prone to explode. Therefore, it is necessary to explore hydrogen explosion inhibitor to prevent and mitigation hydrogen explosions. In this study, the synergistic effect of the combination of inert gas and ultrafine water mist on the suppression of hydrogen explosion was studied by using a standard 20 L spherical explosive container bomb. The results of the study indicate that the combined use of inert gas and ultrafine water mist yields better suppression effects in terms of explosion pressure, flame propagation speed, and flame cellular structure formation, compared to the use of a single inert gas. Inert gas and ultrafine water mist have synergistic effects, but the synergistic effect of N 2 was significantly stronger than that of CO 2. Through chemical kinetic simulation, it was found that the formation rate of O, H, and OH, which were three active free radicals, decreased significantly compared with that of the single inhibition condition in the process of inhibiting the hydrogen explosion reaction by inert gas and ultrafine water mist. The pairing of nitrogen with ultrafine water mist demonstrates a superior collaborative effect in comparison to the combination of carbon dioxide and ultrafine water mist. • Synergistic explosion suppression effect of inert gas and ultra-fine water mist. • Twin-fluid can effectively slow down the formation of flame honeycomb structures. • Analyzed the synergistic explosion suppression mechanism of twin-fluid. • N 2 is more synergistic than CO 2 with ultra-fine water mist. [ABSTRACT FROM AUTHOR]

In this study, the effects of different silicon carbide (SiC) particle sizes on the viscosity and curing behavior of alumina (Al 2 O 3) ceramic suspensions were thoroughly investigated. The findings revealed that increasing the size of SiC particles led to a noticeable decrease in the viscosity of the suspension. The Al 2 O 3 ceramic suspension with 0.6 μm SiC powder demonstrated a shallower cure depth and wider excess width compared to the suspension with 1.0 μm SiC powder. Sintering tests demonstrated that the properties of the SiC–Al 2 O 3 ceramics improved at higher sintering temperatures. Moreover, a high-performance honeycomb ceramic was successfully designed and fabricated with a porosity and compressive strength of 30.8 % and 188 MPa, respectively. Finally, the SiC–Al 2 O 3 honeycomb ceramics were effectively applied in heat insulation and oil-water separation applications, demonstrating their remarkable capabilities. [ABSTRACT FROM AUTHOR]

The increasing demand for sustainable aviation solutions has intensified the development of hydrogen-fueled gas turbine combustors, necessitating advanced manufacturing techniques like Additive Manufacturing (AM). Traditional methods fall short in addressing the complex needs of these combustors, making AM essential due to its ability to create intricate, efficient, and lightweight components. This letter highlights AM's transformative impact on hydrogen gas turbine production, emphasizing enhanced design, assembly, and performance. AM provides significant design flexibility, enabling the fabrication of complex lattice and honeycomb structures that improve fuel efficiency and aircraft performance. It also streamlines assembly by integrating multiple parts into a single component, reducing complexity and waste, and thus optimizing cost and environmental impact. Additionally, AM's capabilities for rapid prototyping and on-demand production accelerate development cycles and foster customization. Furthermore, the letter discusses the integration of Design for Additive Manufacturing (DfAM), and Artificial Intelligence (AI) in optimizing combustion chamber designs. These technologies enhance predictive performance, and structural integrity, and address key challenges such as emissions and combustion stability. AI advances digital twin technology, significantly boosting efficiency and reducing the environmental footprint of hydrogen gas turbines. [ABSTRACT FROM AUTHOR]

The excellent recyclability of SiC foam renders it an ideal catalyst in the field of photocatalytic degradation, however to further improve its photocatalytic efficiency remains a major challenge in current research. In this regard, a honeycomb-like porous SiC foam was successfully constructed through freeze-drying and polymer-to-ceramic derivation method, with two-dimensional Ti 3 C 2 T x nanosheets anchored on its three-dimensional framework. Their photocatalytic performances were evaluated by the degradation of methylene blue (MB) under visible-light irradiation. All Ti 3 C 2 T x /SiC hybrid foams show superior photocatalytic degradation capability compared with SiC foam, with a highest removal rate (adsorption and degradation) reaching 94.4% for TSF-4, denoting an increasement of 50.4%. Even after five cycles, the removal rate remained at 91.4% with only a slightly loss of 3%, suggesting its excellent recycling performance. These desirable results stem from the unique structural design, in which the porous structure facilitates the contact between catalyst and pollutant, while the Ti 3 C 2 T x /SiC heterojunction promotes effective separation of photogenerated carriers. This work paves the way for the development of lightweight, efficient and easily recyclable photocatalyst for wastewater purification. [ABSTRACT FROM AUTHOR]

Silicon oxycarbide (SiOC) ceramics have been used to fabricate microwave-absorbing metastructures, demonstrating impressive absorption capabilities. However, SiOC ceramic metastructures with excellent performance require simple fabrication processes and appropriate mechanical and electromagnetic properties. In this study, a solvent-free photosensitive polysiloxane preceramic was developed by blending methoxy/hydroxy polysiloxanes with acrylates, with a ceramic yield of over 60% after curing using a novel two-step ultraviolet (UV)/thermal method. The composition and microstructure of SiOC ceramics can be designed by controlling the preceramic composition. Dense, crack-free gyroid-shellular shaped triple periodic minimal surface (GS-TPMS) electromagnetic metastructures were fabricated using digital light processing (DLP) 3D printing technology. By designing the porosity of the GS-TPMS structure to 51%, an effective absorption bandwidth that covers the X-band can be achieved at a thickness of 3.1 mm. The honeycomb structure, with a geometric density of 0.69 g/cm3, exhibited a high compressive strength of 107.05 MPa. This paper presents an efficient approach for the prompt and customized fabrication of lightweight ceramic metastructures with outstanding microwave absorption properties. • A solvent-free polysiloxane/acrylate hybrid preceramics is developed for 3D printing. • The UV/thermal two-stage treatment achieved cross-linking curing of the preceramics. • Multiscale design of SiOC ceramics for enhanced microwave absorption properties. • SiOC ceramic metastructures with effective absorption in the X-band are prepared. [ABSTRACT FROM AUTHOR]

Due to the limitations of the Kramers-Kronig relationship, how to achieve ultra-wide effective absorption bandwidth remains a challenge for typical magnetic-dielectric absorbers. In the present work, we have explored the possibility of obtaining ultra-wide absorption bandwidth in FeSiAl composites with help of efficient electromagnetic (EM) simulation software-Computer Simulation Technology (CST). Flaky FeSiAl powders covered by CeO 2 have been prepared, in which EM parameters can be tuned by filling ratio of FeSiAl/CeO 2 in FeSiAl/CeO 2 -paraffin composites. The filling ratio has an effect on impedance matching and EM parameters by the arrangement of particles in the paraffin. The composite with 30 wt% flaky FeSiAl/CeO 2 achieves an effective absorption bandwidth (EAB) of 6.48 GHz and the optimal microwave absorption efficiency of 1499.3 dB GHz/(wt%⋅m) at 1.9 mm. Integrated with a macroscale honeycomb structural design, the FeSiAl/CeO 2 composites based metastructure exhibits broadband microwave absorption with an EAB of 14.224 GHz covering from 3.776 GHz to 18 GHz and reflection loss of-65.61 dB at 8.5 GHz. The excellent performances of the designed absorber are ascribed to multiple loss by integrating EM parameters of flaky FeSiAl/CeO 2 and the geometry parameters of honeycomb metasrtucture. The present work makes flaky FeSiAl/CeO 2 composites possible to achieve broadband microwave absorption. [ABSTRACT FROM AUTHOR]

A simple in-situ method was proposed to synthesize surface coating of SiC nanowhiskers on cordierite honeycombs by aluminothermic, silicothermic, and carbothermic reduction reactions. The surface coating of SiC nanowhiskers was synthesized by controlling the partial pressure of SiO gas on the surface of honeycombs, based on the pore-forming process using aluminium(Al) agent. Increasing the porosity of the honeycombs provided aisles to volatilize SiO gas, and the growth of SiC nanowhiskers changed from inside the honeycomb wall to on the honeycomb surface. SEM and TEM observations revealed that the relatively high porosity (≥45%) and sintering temperature (1250–1300 °C) were necessary for obtaining surface coating of SiC nanowhiskers, and the nanowhisker-coating having the smooth morphology and a thickness of ∼150 µm was obtained at 1250 °C. Compared with cordierite honeycombs without SiC nanowhiskers, SiC nanowhiskers inside the honeycomb walls could improve the compressive strength and thermal conductivity with increasing rates of 121% and 123%, respectively, and the surface coating of SiC nanowhiskers increased the specific surface area of the honeycombs by 241 times. [ABSTRACT FROM AUTHOR]

Peculiarities of sintering of foamy ceramic filters based on submicron aluminum oxide powders with additions of titanium oxide and manganese dioxide nanopowders are considered. The processes of removal of polymeric and binder paraffin material during sintering have been studied. The physical and mechanical properties of the obtained porous permeable filters with a foamy structure were analyzed in details. At a sintering temperature in an air atmosphere of 1350 °C, sufficiently high physical and mechanical properties were obtained, which made it possible to use the developed filters as catalyst carriers for vehicle exhaust gases. Bench comparative tests have shown that ceramic filters with a foamed structure are promising catalysts for afterburning car exhaust gases instead of ceramic honeycomb blocks of catalyst carriers. The developed technology allows reducing the sintering temperature of porous foam ceramic filters to 1350 °C and replacing expensive high-temperature ceramic heaters with cheaper nickel-chromium ones. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with high mortality. The Food and Drug Administration-approved drugs, nintedanib and pirfenidone, could delay progressive fibrosis by inhibiting the overactivation of fibroblast, however, there was no significant improvement in patient survival due to low levels of drug accumulation and remodeling of honeycomb cyst and interstitium surrounding the alveoli. Herein, we constructed a dual drug (verteporfin and pirfenidone)-loaded nanoparticle (Lip@VP) with the function of inhibiting airway epithelium fluidization and fibroblast overactivation to prevent honeycomb cyst and interstitium remodeling. Specifically, Lip@VP extensively accumulated in lung tissues via atomized inhalation. Released verteporfin inhibited the fluidization of airway epithelium and the formation of honeycomb cyst, and pirfenidone inhibited fibroblast overactivation and reduced cytokine secretion that promoted the fluidization of airway epithelium. Our results indicated that Lip@VP successfully rescued lung function through inhibiting honeycomb cyst and interstitium remodeling. This study provided a promising strategy to improve the therapeutic efficacy for IPF. [Display omitted] • Inhaled nanoparticles were fabricated to enhance drug lung delivery. • Verteporfin inhibited the formation of honeycomb cysts. • Pirfenidone inhibited the remodeling of alveoli interstitium. • This study provided a promising strategy to improve antifibrotic efficacy. [ABSTRACT FROM AUTHOR]

A significant challenge in electrolyte-supported solid oxide fuel cells (SOFCs) pertains to the substantial thickness of the electrolyte, resulting in elevated operational temperatures that hinder commercial viability. In this research, we utilized digital light processing (DLP) 3D printing technology to fabricate ultra-thin honeycomb electrolyte-supported SOFCs and subsequently evaluated their performance. Through the use of ultraviolet absorbers, we achieved a shallow curing depth (60.3 μm), which facilitated the creation of ultra-thin electrolyte samples. We investigated the mechanical properties of electrolytes with various honeycomb structures, finding that the square honeycomb structure exhibited the highest mechanical integrity, with an average failure load of 1.01 N. Finally, we assessed the electrochemical performance, observing a substantial power density of 215.4 mW/cm2, representing a twofold increase compared to the 114 mW/cm2 achieved by the same method in a flat primary cell. [ABSTRACT FROM AUTHOR]

Porous honeycomb mullite ceramics were controllably fabricated in-situ using stereolithography 3D printing. The effects of the dispersant type and content on the rheological behavior of the mullite precursor slurry were investigated. Additionally, the influence of the debinding atmosphere (air and argon) on the quality of the samples and formation of cracks was also studied. The results indicated that oleic acid (OA), 3-glycidoxypropylthrimethoxysilane (KH560), and disperbyk (BYK111) displayed the capability to create low-viscosity and highly stable slurries. Among these KH560 was proved to be the most effective. The mullite precursor slurry containing 4 wt% KH560 dispersants exhibited a shear thinning behavior. It displayed a viscosity of 0.26 Pa·s at a shear rate of 30 s−1. The mullite ceramic parts displayed good a dimensional resolution at an exposure dose of 5.47 mJ/cm2. During the debinding process, the printed parts were susceptible to cracking and deformation in air, but remained devoid of defects in argon. When the samples were sintered at 1600 °C, the corundum phase transformed almost completely into the mullite phase. The linear shrinkage values were 5.81%, 6.33%, and 10.26% in the O-X, O–Y and O-Z directions, respectively. [ABSTRACT FROM AUTHOR]

In this study, Al 2 O 3 honeycomb sandwich structures with different core geometries (square, triangular, circular) have been fabricated through an additive manufacturing system based on the stereolithography (SLA) method. The debinding procedure was performed under both nitrogen and air atmospheres. The impacts of the debinding atmosphere and core geometry on the densification and mechanical properties were investigated. The stiffness and flexural strength of the ceramics were examined experimentally using an impulse excitation of vibration technique and a three-point bending test, respectively. The specific stiffness and specific strength of the ceramics were also evaluated, with the core geometries taken into consideration. The outcomes showed that higher densification was achieved when the ceramics were exposed to debinding in nitrogen. The stiffness values were found to be similar for the same debinding condition within the honeycomb sandwich structures, irrespective of the core geometry. Notably, the highest specific stiffness (98 MNm/kg) was achieved for the samples subjected to debinding in nitrogen with a square core geometry. Furthermore, ceramics with square cores for debinding in a nitrogen atmosphere also demonstrated the highest performance in terms of specific strength (110 kNm/kg) within the honeycomb structures. This study demonstrated that Al 2 O 3 honeycomb sandwich structures with square cores may be suitable candidates for lightweight-structure demanding applications. [ABSTRACT FROM AUTHOR]

This paper proposes an innovative class of two-and-a-half dimensional (2.5D) hybrid continuous fiber reinforced lattice structures (CFRLSs) that rationally combine distinct lattice designs to leverage the tensile strength of fibers for achieving superior compression performance. These hybrid structures are fabricated through a self-supporting suspension printing (SSSP) method, which enables the fabrication of suspension structures across substantial gaps through continuous fiber 3D printing (CF-3DP). The compression behavior of the proposed 2.5 D hybrid CFRLSs was optimized by focusing on two key variables in hybridizing the basic lattice along the build direction: composition ratio and distribution strategy. Finite element and analytical models were developed to elucidate their three failure mechanisms and related control strategies. Compared to the conventional single-type structure, i.e., honeycomb design, the proposed hybrid structures show a substantially higher compression performance, with improvements of up to 141.3 % and 330.1 % in specific strength and modulus, respectively, even at a lower density. This hybrid lattice design method based on SSSP opens up new horizons for engineering high-performance CFRLSs with superior compression performance by fully exploiting the design freedom offered by CF-3DP. [Display omitted] [ABSTRACT FROM AUTHOR]

CFRP (carbon fiber reinforced composites)/honeycomb sandwich structures are widely used in aerospace, automotive, and high-speed rail industries due to their excellent mechanical properties and lightweight characteristics. This study investigates the impact of three designed toughened interfaces on the three-point bending performance of honeycomb structures. The results show that introducing a multiscale toughened interface made of poly(p-phenylene benzobisoxazole) (PBO) fibers grafted with polydopamine (PDA) and multi-walled carbon nanotubes (CNT) increases the peak load and post-peak load of the sandwich structure by 49.7 % and 51.9 %, respectively, and the absorbed energy by 92.4 %. This toughened interface adjusts the stress relationship between the panel, interface, and honeycomb, altering the deformation process and crack propagation mode of the sandwich structure. The micro-nano fibers form fiber bridging at the interface, changing the crack extension mode between the interfaces, transforming the delamination from a single debonding to the combined action of plate core debonding and honeycomb core buckling. Additionally, experimental results show that PBO fibers treated with PDA and CNT exhibit significantly improved surface roughness, Surface area per unit mass, wettability, and tensile strength, which delay and prevent crack propagation at the interface, effectively reducing panel debonding at the bonded joints. [Display omitted] • The interface made of PBO fibers grafted with PDA and CNT has increased the mechanical performance. • This toughened interface changed the stress relationship and crack propagation mode of the sandwich structure. • The micro-nano fibers have changed the crack extension mode between the interfaces. [ABSTRACT FROM AUTHOR]

• Ordered AAO structures with interpore distance of 385–420 nm forms in 1 m H 3 PO 3. • The apparent activation energy of al anodizing in 1 m H 3 PO 3 is 65 kJ/mol. • Novel approach to two stage anodizing at high voltages is proposed. • AAO crystallizes in γ-, δ-, and θ-phases at 820 °C and in α-Al 2 O 3 at 1310 °C. • Ordered arrangement of pores is preserved in α-Al 2 O 3 after annealing at 1310 °C for 60 h. Aluminium anodizing in phosphonic acid is known to produce anodic aluminium oxide (AAO) honeycomb structures with large interpore distances. However, detailed information on two-stage anodizing in phosphonic acid and annealing conditions required for the crystallization of AAO cell walls have not been reported yet. Here, the kinetics of aluminium anodizing in 1 M phosphonic acid and the thermal behaviour of the resulting AAO have been studied in detail. The apparent activation energy of aluminium anodizing is 65 kJ mol–1 and the AAO growth rate reaches 15 µm h–1 before oxide "burning". A universal approach for stable two-stage anodizing at high voltages allowing to prevent porous structure rearrangement in the upper part of AAO is proposed. It involves the preliminary formation of a dense barrier alumina layer by anodizing in a weak acid electrolyte before the second anodizing step in phosphonic acid. The crystallization pathways of AAO obtained in phosphonic acid electrolyte are revealed based on differential scanning calorimetry, X-ray diffraction, and solid-state nuclear magnetic resonance techniques. The designed annealing program allows one to preserve the honeycomb porous structure after the crystallization of AAO in corundum at 1310 °C for 60 h. AAO obtained in phosphonic acid possesses high thermal stability and, thus, is promising as a support for gas sensors and fuel cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Honeycomb structures offer the benefits of being lightweight and having high out-of-face compressive stiffness, making them a popular choice for aerostructures. The present study delineates the design and active vibration control effect for fiber-reinforced cruciform honeycomb laminates (CHLs) characterized by variable parameters. Employing a continuous fiber 3D printer, carbon fiber filament and shape memory polymers (SMPs) were utilized in the fabrication of the specimens. Differential equations of motion for CHLs were deduced from Kirchhoff plate theory. To ascertain their frequency response, these laminates were subjected to a sinusoidal swept frequency excitation. Subsequently, the classical proportional integral derivative (PID) program was employed to scrutinize the efficacy of closed-loop active vibration control on CHLs. The investigation extended to analyzing the impact of active vibration control across laminates with disparate parameters, including an examination of the convergence speed during vibration control procedures. A comparative analysis of simulated versus experimental data revealed a substantial consonance between the two, thereby corroborating the accuracy of the experimental findings. This study offers crucial insights and reference value for the utilization of CHLs in the aerospace industry. [ABSTRACT FROM AUTHOR]

The Glycerol monolaurate (GML) oleogel was induced using Camellia oil by slowly raising the temp to the melting point (MP) of GML. Whey protein isolate (WPI) solution with different ratios was composited with GML oleogel by emulsion template methods, forming dense spines and honeycomb-like networks and impressed with an adjustable composite structure. Textural results showed that compared with single GML-based oleogels, the GML/WPI composite oleogels had the advantages of high hardness and molding, and structural stability. The composite oleogels had moderate thermal stability and maximal oil binding (96.36%). In particular, as up to 6 wt% GML/WPI, its modulus apparent viscosity was significantly increased in rheology and similar to commercial fats. Moreover, it achieved the highest release of FFA (64.07%) and the synergy provided a lipase substrate and reduced the body's burden. The resulting composite oleogel also showed intermolecular hydrogen bonding and van der Waals force interactions. These findings further enlarge the application in the plant and animal-based combined of fat substitutes, delivery of bioactive molecules, etc. , with the desired physical and functional properties according to different proportions. [Display omitted] • Monoglycerides and proteins imparted spines and honeycomb network structures. • Oleogels exhibited favorable oil-holding, stronger rigidity, and thermal stability. • Hydrogen bonding-induced protein polymerization was the dominant interaction within composite oleogels. • The rheological properties were similar to commercial fats. • The synergy provided a lipase substrate and reduced the body's burden. [ABSTRACT FROM AUTHOR]

Cermet is a promising inert anode material to solve the problem of high carbon emission and bearing C-F harmful gas generation of primary aluminum produced from bauxite using molten electrolysis with carbon anode. However, a major challenge for traditional methods is to ensure that the cermet inert anode simultaneously has good conductivity, corrosion resistance, and strength. Herein, a new ultrafast pressureless sintering (UPS) method is developed to greatly improve the conductivity of metal ceramic inert anode materials while ensuring good corrosion resistance and strength. In a departure from conventional practice that metal phase undergoes local enrichment accompanied by irregular formation of ceramic particles at low heating rates, here UPS achieves rapid diffusion and uniform distribution of metal phase at regular ceramic particle interfaces during liquid phase sintering. The new method is applicable to Ni-based cermet and the production of Ni-based cermet inert anode with excellent conductivity in a few tens of seconds has been demonstrated, which is able to improve the quality of cermet inert anode requiring a low energy input. The conductivity of cermet produced by the applied UPS process is 15-fold higher than that of other pressureless sintering processes with low heating rates. These Ni-cermet inert anodes exhibit high corrosion resistance and density with excellent mechanical properties. This rapid sintering technique facilitates the structural design of inert anodes and develops a pathway of new systems with scalable, efficient, and high-quality sintering of composite materials. • High conductivity nickel-based cermets with penetrating honeycomb structure produced in minutes using ultrafast high-temperature sintering. • Large gradient heat field enables rapid melting of the metal, which driving a uniform distribution of the Ni at the ceramic interface. • The honeycomb metal phase increases the conductivity of the metal ceramic by 15 times compared to its conventional sintering process. [ABSTRACT FROM AUTHOR]

A TC4/TA2 honeycomb structure was fabricated using Selective Laser Melting. The study primarily investigates the impact of process parameters on the mechanical properties of as-built TC4 and TA2, as well as the correlation between microstructure and mechanical properties in as-built TC4/TA2. The resulting composite displays a heterogeneous structure of acicular α′ and columnar β grains, and exhibits superior mechanical properties with a maximum tensile strength of 1081 MPa and an average elongation of approximately 14 %. These outstanding mechanical properties are attributed to the strengthening effect of acicular α′ martensite and synergistic effect between dissimilar materials. The anisotropy of the mechanical properties of heat-treated TC4/TA2 decreased, which is attributed to the transformation of the columnar grains to the basket-waving structure and equiaxed structure. • The TC4/TA2 honeycomb structure was fabricated by the Selective Laser Melting (SLM). • The unique scanning strategy caused the microstructure on the sop surface to exhibit a checkerboard pattern. • The temperature gradient and G/R value played an important role in the epitaxial growth of columnar grains. • The reasons for the difference in mechanical properties of the as-built part in different directions were explained. [ABSTRACT FROM AUTHOR]

In this paper, the effect of Al mole ratio on phase evolution, damping capacity and mechanical properties of the Al x CrFe 2 Ni (indicated by Al x , x = 0.3, 0.4, 0.5 and 0.7) medium-entropy alloys (MEAs) was investigated. The results show that the structure of the Al x MEAs changes from the face-centered cubic (FCC) phase dominated by the Al 0.3 alloy to the body-centered cubic (BCC) phase dominated by the Al 0.7 alloy. As the volume fraction of the BCC phase increases the corresponding grain size of the alloys decreases and then increases, which increases the ferromagnetic properties and decreases interfacial area in the Al x alloys. The high damping capacity of Al 0.5 and Al 0.7 alloys is corresponding to 0.05545, and 0.05044, respectively, under the synergistic effects of ferromagnetic damping and interfacial damping. The special honeycomb-like morphology of FCC phase distributed in the BCC matrix gives the Al 0.5 alloy the highest damping capacity and yield strength. • The honeycomb structure composed of FCC and BCC phase is more beneficial to improve the damping performance of Al 0.5 CrFe2Ni alloy. • The increase of Al mole ratio of Al x CrFe 2 Ni medium entropy alloys (MEAs) promotes the phase transition tendency from FCC to BBC. • The Al 0.5 CrFe 2 Ni MEA shows higher damping capacity of 0.05545. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bionic pattern of honeycomb and cactus spines coupling (BPHCSC) was designed. • The fog collection efficiency of BPHCSC enhanced by 23.5%. • Circular, triangular, and rectangular pattern were designed on the basis of BPHCSC. • A directional fog collection device was designed on the basis of BPHCSC. Fog collection has become one of the effective means to solving water scarcity. Wettability-mixed patterned surfaces exhibit great potential in fog collection. In this article, the desert beetle, honeycomb structures and cactus spines served as an inspiration in the proposal of a bionic pattern of honeycomb and cactus spine coupling (BPHCSC) that can efficiently collect fog. First, a superhydrophobic (SHB) surface was successfully prepared on the surface of 5052 Al alloy through combined electrochemical etching with fluorosilane modification. Subsequently, laser etching technology was used in the precise etching of a superhydrophilic BPHCSC on the SHB surface. Compared with the fog collection efficiencies of a single SHB surface and the honeycomb-like wettability-mixed patterned surface composed of rectangular channels, that of the prepared BPHCSC surface increased by approximately 23.5% and 4.27%, respectively. In addition, a thorough exploration was conducted on the effects of factors, such as the distance between the sample surface and the fog outlet, tilt angle and the number of laser etchings, on fog collection efficiency. This study provides a new idea for fog collection and exhibits a broad application potential in fields, such as microfluidic systems, droplet manipulation and cell screening. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flexible, air-permeable, and conductive non-woven silk fabric (nSF) was prepared. • A TPU-based honeycomb microporous structure was constructed within the silk fibers. • The conductive silk fabric shows stable humidity response and thermal response. • The conductive silk fabric displays reliable strain sensing ability. • The silk fabric shows effective EMI shielding performance and Joule heating management. Silk-based conductive composites have attracted much attention for applications in flexible smart electronics. However, silk-based conductive composites that combine high air permeability, Joule heat management, electromagnetic interference (EMI) shielding and multimodal responsiveness are still challenging. In this paper, flexible porous non-woven silk fabric (nSF)-based conductive composites with the aforementioned properties are designed and developed by a freeze-induced assembly and surface micro-dissolution adhesion (FASMA) process to introduce carbonyl carbon nanotubes (C-CNTs), MXene and thermoplastic polyurethanes (TPU) into the inter-fiber network structure of nSF, with the aim of constructing a high-performance multimodal sensing platform. Functioning as a flexible strain sensor, the nSF-based composite can detect strains as low as 0.05 % with rapid response and recovery time of 125 ms and 146 ms, respectively, and can be used to detect full-size human motion signals. The nSF-based composite has a good humidity response at 0–85 % relative humidity (RH) and a sensitive and reliable thermal response. In additionally, the nSF-based composites also have Joule heat management and EMI shielding functions. All these multi-functional applications demonstrate the advantages of the prepared flexible porous nSF-based composites in the field of flexible smart electronics. [ABSTRACT FROM AUTHOR]

A novel, 12 mm multilayer dielectric gradient honeycomb absorber (MGHA) was designed, fabricated and analyzed with a double layer metasurface consisting of a resistive film and an artificial magnetic conductor (AMC) checkerboard. Despite its thin profile, the MGHA demonstrates significantly enhanced absorption performance across a wide frequency range due to the impedance of the composite structure. Furthermore, two distinct metasurfaces are integrated into the dielectric gradient multilayer honeycomb absorber to further enhance its low-frequency properties without increasing thickness. This structure exhibits wideband absorption from 2.8 GHz to 18 GHz, featuring three absorption peaks at 3 GHz, 11 GHz and 16 GHz. The relative bandwidth can reach nearly 136.6 % of that achieved by a common honeycomb absorber with the same thickness, while maintaining an absorption peak reflection of about −22dB. The great attenuation of incident waves is attributed to Ohmic loss on the resistive film, electric resonance effect on the checkerboard, and magnetic resonance near 17 GHz on the checkerboard metasurface. The proposed MGHA structure holds significant potential for applications in aerospace and military. • Multi-layer honeycombs have better absorption performance than single-layer ones of the same height because of improved impedance matching. • Three types of resistive film metasurface are added to the multilayer dielectric gradient honeycomb absorber, improving absorption. • A multilayer absorber with resistive film and AMC checkerboard metasurfaces has wideband absorbing property from 2.8 GHz to 18 GHz, which is almost 136.6% better than a common honeycomb absorber of the same thickness. • Hence, this novel multilayer dielectric gradient honeycombs absorber with double layer metasurface shows greatly potential application in aerospace and military and will attract wide readership. [ABSTRACT FROM AUTHOR]

Metamaterials with honeycomb structures have garnered significant attention in energy-harvesting applications. In this study, we present three conventional cantilever resonators with honeycomb substrates featuring positive, zero, and negative Poisson's ratios (PPR, ZPR, and NPR). Polyvinylidene fluoride consisting electrode layers is attached to the substrate surfaces. A process parameter optimization method of honeycomb structure design was proposed, in which finite element simulation for data generation, backpropagation neural network for data prediction, and nondominated sorting genetic algorithm II (NSGA-II) for data optimization. This method aims to determine the optimum geometric parameters of the honeycomb structures, which addresses general cantilever resonators, where the first structural vibration modes are typically of interest and have to match specific target eigenfrequencies for engineering applications. Finite element simulations show that the peak voltage of PPR, ZPR, and NPR resonators at 75 Hz is increased by 12 %, 22 %, and 32 %, respectively, due to optimization. The optimized structures are fabricated and measured to validate the numerical model. The performance of the resonators with cellular materials featuring a full characteristic range of Poisson's ratios is then compared systematically to explore their energy-harvesting potential. The results revealed that the NPR structure exhibits superior performance for energy-harvesting. Moreover, stress distribution and displacement have also been highlighted in this paper. [Display omitted] • A backpropagation neural network is trained to predicting the performance of piezoelectric energy harvester. • An optimization method combining backpropagation neural network and evolutionary algorithm is developed. • The performance of piezoelectric energy harvesters with different cellular substrates are systematically compared. • The optimization results are validated by finite element analysis and experiments. [ABSTRACT FROM AUTHOR]

• Thermal battery resilience under high-impact conditions was assessed to sustain continual power supply for electronic devices equipped with artillery projectiles. • Honeycomb buffering devices with different wall thicknesses were adopted to compare their energy-absorption capacities. • Large-scale gas-gun tests and finite element simulations comparing buffering devices revealed distinct deformation patterns influencing impact deceleration. • The thermal battery retrieved from the gas-gun test proved to have reliable impact resilience for the target performance. Modern warfare relies heavily on electronic equipment, necessitating reliable energy sources like thermal batteries. Assessing their impact resilience, a study employed honeycomb-structured Al plates as buffering devices in a large-scale gas gun simulating artillery fire. Comparison between peak curves from gas-gun tests and simulations with varying honeycomb wall thicknesses revealed unique patterns, attributed to the buffering device's deformation-restoration process. Different honeycomb wall thicknesses led to varying deformation behavior and impact deceleration, complicating effective energy absorption assessment. Stepped honeycomb wall designs aimed to balance compression, extending energy absorption and reducing deceleration peaks. Prototype honeycomb buffering devices showed improved energy absorption and reduced deceleration during gas-gun tests. Gas-gun tests highlighted complexities in energy absorption assessment, with designs proposing improved energy absorption and reduced deceleration. The actual gas-gun test launched a projectile equipped with a thermal battery and buffering device, resulting in slight casing deformation, while battery cells remained intact, exceeding the standard discharge time (1 h). [Display omitted] [ABSTRACT FROM AUTHOR]

• A new type of T-beam bridges deck: honeycomb T-beam. • Static comparison test of conventional T-beam and honeycomb T-beam. • Finite element model verified by static test. • Calculation of crack width and reinforcement optimization. The inefficiency in the construction of intermediate diaphragms for T-beam bridges (referred to as conventional T-beam), has long been a significant research concern. This study focuses on a novel bridge deck design (referred to as honeycomb T-beam), which effectively eliminates the need for intermediate diaphragms, thus enhancing construction efficiency. Segment models of both conventional T-beam and honeycomb T-beam were designed and fabricated, and their transverse mechanical performance was compared through transverse static tests. Additionally, numerical simulations using ABAQUS were conducted and validated with experimental data. Based on the numerical model of honeycomb T-beam, crack width calculation and reinforcement optimization were performed. The main conclusions are as follows: (1) The design of honeycomb T-beam allows for less reinforcement, making it more economical while ensuring that the bearing capacity reaches the same level. (2) Honeycomb T-beam exhibits superior durability and bearing capacity, with a failure mode that is more ductile. (3) The results of numerical simulation highly coincide with experimental results. Besides, this paper proposes and validates a practical method for crack width calculation. (4) Parametric analysis show that increasing the reinforcement area at right inner hole of honeycomb T-beam by 10% can enhance the bearing capacity by 18%. Based on this, design suggestions are made for honeycomb T-beams and other perforated structures. [ABSTRACT FROM AUTHOR]

Ultralight all-CFRP honeycomb sandwich cylinders were fabricated using a stretching process. Subsequently, critical failure loads corresponding to five typical failure modes of the sandwich cylinders under axial compression were obtained through theoretical derivation. Three-dimensional failure mechanism maps were generated, which intuitively revealed the influence of the dimensionless parameters on structural failure. The panel thickness was selected as a variable, and quasi-static axial compressive tests were performed on the sandwich cylinders. Two failure modes, intracellular buckling and face crushing, were observed, which is consistent with theory. The experimental results were analysed and discussed systematically. The ultralight all-CFRP honeycomb sandwich cylinders were compared with existing cylinders to reveal their bearing advantages. The established failure mechanism maps provide guidance for the preparation and optimisation of honeycomb sandwich cylinders. Compared with the traditional fabrication processes of honeycomb cores, the novel stretching process is expected to achieve mass production, which is helpful to provide technical support for the lightweight manufacturing of aerospace structural components. [ABSTRACT FROM AUTHOR]

• The effect of thickness and reinforced strut gradients on the crushing response of RRH is explored. • Two plateau stresses of RRH specimens are derivated theoretically with a relative error of less than 7 %. • Both thickness and catenary gradients inspire a multi-step deformation mode and multi-plateau stress. • Some suitable thickness and catenary gradients are discovered under different impact velocities. Re-entrant honeycombs have demonstrated promising applications in engineering fields attributed to better manufacturability and adaptability. Herein, the reinforced re-entrant honeycombs (RRH) with thickness and reinforced strut gradients are proposed, respectively, and their in-plane energy absorption is investigated through experiment, theoretical analysis, and simulation. Metallic specimens of uniform and graded RRH are manufactured through a step-by-step method. The deformation mode and plateau stress (PS) of these specimens are significantly influenced by both thickness and catenary gradients. Two PSs of RRH specimens are predicted theoretically with a relative error of less than 7.0 %. Subsequently, the deformation mode and energy absorption of uniform and graded RRH, subjected to varying load rates, are investigated thoroughly with a numerical method verified against the experimental data. The results show that both thickness and catenary gradients can inspire multi-step deformation mode and prevent instability deformation. Compared to uniform RRH (U-RRH), the specific energy absorptions (SEA) of thickness gradient (TG)-123 (123 represents that the thicknesses from impact end to fixed end are t 1 , t 2 , t 3) and TG-213 are enhanced by 52.2 % and 49.8 %, respectively, under quasi-static compression, the SEA of TG-132 and TG-123 are raised by 41.6 % and 20.2 %, respectively, under low-velocity impact, and the SEA of strut gradient (SG)-123 is 66.7 % higher than that of U-RRH under high-velocity impact. More significant auxetic deformation does not always mean better energy absorption because there is also an increased tendency of global instability and earlier densification points. This work provides a novel approach to designing high-energy absorption honeycombs with low structural complexity. [ABSTRACT FROM AUTHOR]

• Thermal-force external coupling enhances polyimide molecular chain orientation. • Orientation modulation increases the honeycomb shear strength 10 times to 1.07 MPa. • Excellent thermal performance of polyimide aerogel honeycomb (T d5% >650 °C). • Fabricating integrated lightweight honeycomb structures using the formwork method. Lightweight honeycomb structures are widely used in applications that require high strength-to-weight ratios and low densities, including aircraft, automobiles, and various engine components. However, due to the immaturity of microstructure conditioning techniques and the fact that highly porous structures usually fracture during stretching, it is challenging to obtain both high-strength and lightweight porous structures. Herein, a newly developed multilayer interconnected polyimide aerogel-based paper honeycomb is successfully prepared based on the ice crystal reverse template method and multi-level structure regulation via chemical and physical interactions. The synergistic effect of the hot extrusion-stress strategy and the heat imidization process provides the submicron layer of the paper honeycomb wall with more orderly molecular chain stacking, excellent orientation, and an enhanced folding degree between layers. The prepared polyimide aerogel paper honeycombs have low density (approx. 8–9 kg/m3), good shear strength of 1.07 MPa (W direction) and 0.86 MPa (L direction), excellent specific compressive strength (0.38 MPa), and excellent thermal stability. These integrally molded polyimide paper honeycombs, as sandwich resin-based composite structures, provide a new versatile platform for aerospace and marine applications. [ABSTRACT FROM AUTHOR]

• The novel helical layered square honeycombs exhibit higher strength (∼176 %) and specific energy absorption (∼502 %) than regular square honeycomb. • The quasi-static compressive behaviors of helical-layered and regular square honeycombs are compared. • The deformation modes of helical-layered square honeycombs are dominated by the relative density and the number of helical layer. • The mechanical properties and energy absorption capacity improved by increasing the number of helical layer. • The failure mechanisms of helical-layered square honeycombs are dominated by layer cracking. Bionics shape design of cellular structures has the potential advantage of improving their both mechanical properties and energy absorption capabilities to the conventional honeycomb structures. In this article, inspired by square porous wood and DNA double helix, we demonstrate the creation of the novel helical layered square honeycombs (HLSHs) that simultaneously exhibit high strength and excellent energy absorption capacity. In-plane compression experiments and finite element simulations revealed that helical structure can effectively strengthen every unit cell to resist local stress concentration which always leads to rapid strain localization and finally followed by catastrophic collapse. Furthermore, the stiffness, strength and energy absorption capability can be continuously improved by increasing the number of helical layers. More specifically, the HLSH-4L (4 layers) exhibits higher collapse stress (∼176 %) and specific absorption energy (∼502 %) compared with that of regular square honeycomb (RESH). The investigation of deformation and failure behavior show that the helical structure can supply high cell-buckling resistance and facilitate the "X" shape deformation band. Besides, the helical structure also caused the transition of failure mechanisms from printing fibers tearing in RESH to layer cracking in HLSHs. This study can present insight into the design of lighter and stronger honeycomb. [ABSTRACT FROM AUTHOR]

Thermal characterization of honeycomb core sandwich panels with GFRP skins by theoretical formulations, and experimental methods followed by corroborating numerical models help identify the effective thermal conductivity in both the out-of-plane and in-plane directions. Swann–Pitman's semi-empirical model formed the basis for the theoretical understanding of heat transfer in honeycomb core sandwich panels. Experimental approach involved a setup based on guarded hot plate (GHP) apparatus, and transient laser flash technique while the numerical approach involved FE modeling of the woven composite fabric face sheet by multi-scale modeling using the actual physical dimensions of the yarn e.g., crimp angle, width and height of the yarns etc. obtained using microscopic analysis. The fiber volume fraction of the experimental samples was estimated both by image analysis and burn-off method using Thermogravimetry (TGA). Various numerical models based on Mechanics of Structure Genome (MSG) and randomized fiber distribution in the yarns at the micro-level are compared with the experimental results to arrive at the model that most closely mimics real situation. Then, the numerical model is used to predict the thermal conductivity of the composite as the fiber volume fraction and crimp angle varies. • Heat flow in sandwich structures with composite facesheets is dominated by core cell wall conduction. • Better representative RVE model of the composite yarns using data from micrograph images, and Procrustes analysis. • E-glass/polypropylene facesheets perform better at low crimp angle and fiber volume fraction (V f). • Small "resin-rich" matrix region disrupts heat flow in facesheets. [ABSTRACT FROM AUTHOR]

Perovskite-based catalysts have been explored as low-cost substitutes for platinum (Pt)- based catalysts for diesel particulate matter (DPM) oxidation. In this work, manganese (Mn)-substituted strontium ferrite (SrFeMnO 3-δ) (SFM) as a catalyst was coated on the honeycomb structure of cordierite support and tested for its catalytic performance for DPM oxidation using a real-world engine. The characteristic diffraction peaks due to the presence of the perovskite structure of SFM were observed for the cordierite-supported SFM. Mn was substituted in the lattice of un-substituted strontium ferrite and no other impurities were formed upon the Mn-substitution. Highly agglomerated SFM particles were formed solely due to the perovskite phase formation temperature (900 °C). The SFM catalyst enhanced catalytic Printex-V oxidation performance compared to its oxidation without the catalyst, where Printex V was used as the model DPM. The SFM catalyst showed high CO 2 selectivity upon the oxidation of DPM. These results infer that the SFM catalyst possesses promise as an alternative to commercially available DOC catalysts based on PGM for DPM oxidation. SFM-coated cordierite support performed much better in terms of particle number, mass and surface area than commercial diesel oxidation catalyst (DOC) or without DOC at no engine load. The performance is substantially higher even at moderate engine loads of up to 40% and comparable at very high engine loads of 100%. Detailed investigations on a real engine exhaust and measurement of crucial parameters like particle number, mass and surface area suggest convincing and relatively rare evidence for its potential as a catalyst for diesel exhaust emission control catalyst. [Display omitted] • Manganese was substituted successfully in the structure of strontium ferrite (SFM). • Perovskite SFM catalyst was coated on the honeycomb structure of cordierite support. • SFM-coated cordierite showed improved diesel particulate matter (DPM) oxidation. • Perovskite SFM catalyst showed higher CO 2 selectivity upon the oxidation of DPM. [ABSTRACT FROM AUTHOR]

• Honeycomb ESP was designed to control NO x and PM emissions from 15-kW boiler. • ESP reduced NO x by 78 % while PM were reduced to a magnitude of ambient air. • ESP removal efficiency was studied in terms of ESP technological parameters. This work investigates the potential of corona discharge to control particulate matter and NO x emissions from small-scale biomass combustion. The electrostatic precipitator (ESP) was designed and used to suppress emissions from a 15-kW heating unit. The ESP was operated at different power modes at both polarities and demonstrated the capability to reduce NO x emissions with a removal efficiency of 78 % while PM concentration was reduced to a magnitude of particle content in ambient air. The efficiency of ESP was evaluated considering the technological parameters, namely the reduced electric field, Nt-product, and specific input energy. The growth in NO x abatement was observed when the energy input exceeded 1 J/L for both polarities and Nt-product exceeded 4.5 × 108 s/cm3/1 × 109 s/cm3 for negative/positive corona. The results of this work may contribute to understanding the processes in corona discharge and optimising corona discharge systems for various applications. [ABSTRACT FROM AUTHOR]

• Three new multi-directional energy-absorbing honeycombs are further designed. • The multi-directional energy absorption characteristics are experimental analyzed. • Detailed and equivalent FE model of corrugated honeycomb are developed and validated. • A new anti-climber equipped with corrugated honeycomb that saves half of the installation length is designed. • The new anti-climber exhibits high energy absorption and strength performance, respectively, in axial and vertical directions. In this study, three novel multi-directional energy-absorbing honeycombs were designed to meet the requirements in the crash of uncertain directions, which are named as bow-shaped honeycomb (BSHC), staggered honeycomb (SGHC) and corrugated honeycomb (CGHC). These innovative designs can significantly narrow the huge gap of the energy absorption capacity between the in-plane and out-of-plane directions of traditional honeycombs. Compression tests were conducted in three orthogonal directions. The BSHC is found to have the smallest densification strain but the highest plateau stress in each direction. The SGHC can only balance the energy absorption between out-of-plane and in-plane- x directions. The CGHC demonstrates a better densification strain and the highest multi-directional energy absorption coefficient. The detailed and equivalent finite element models of CGHC were further established and validated, and both exhibited high accuracy. Finally, a honeycomb anti-climber, with only about half length of the traditional guided honeycomb anti-climber, was designed and equipped with metro vehicles. Simulations were conducted under eccentric collision scenario. The results demonstrated that the CGHC anti-climber was capable of orderly deformation in the axial direction (out-of-plane direction) while effectively resisting the vertical (in-plane- y direction) force during collision. The energy absorption capacity of CGHC anti-climber was significantly enhanced as compared to the HEHC anti-climber under eccentric collision scenario. [ABSTRACT FROM AUTHOR]

Metal foams or cellular structures like honeycombs, can also be evaluated according to mechanical, acoustic, thermal, and chemical resistance parameters in terms of functionality. However, it is vital to investigate the performance of these cellular structures' radiated emission (RE), which can be used as PCB heatsinks. In this study, the radiated emission (RE) performance of honeycomb-structured aluminum foam (or cellular) heatsinks (AFH), which can be considered as unidirectional regular foam, is examined in the frequency range of 1–10 GHz as a novelty. Also, the effect of four primary variables (the geometry of AFH, honeycomb hole direction, honeycomb cell size, and honeycomb cell wall thickness) on the RE performance of AFH is investigated. Unlike classical honeycomb production methods, the investment flask mold casting (loss wax) method is preferred due to the complex offset strip geometry of designed honeycombs. The original design offset hexagonal honeycomb structures were successfully produced using this investment casting method with additive manufacturing technologies from molten metal. While all simulations are carried out using CST Studio Suite, the RE performance of the proposed AFHs is measured in a standard 3 m fully anechoic chamber using a reference horn antenna and vector network analyzer (VNA). When the results are examined, the measured and simulated results agree with each other quietly. Regarding RE, structures with a CPI value of 14 are better at low frequencies, while structures with a CPI value of 3.5 are better at high frequencies. Secondly, the honeycomb cell thickness value does not significantly affect EMI performance. Lastly, although there is no significant difference in EMI in the low-frequency region, it is better to use a directional structure with vertical holes in the high-frequency region. As a result, in the design of AFH, the RE performances of the heatsinks and their thermal performance should be considered. • RE performance of honeycomb-structured aluminum foam heatsinks is examined at 1–10 GHz. • A wax mold created using a 3D printer is used to produce the proposed structure. • In the high frequency region, it is better to use the directional structure with vertical holes. • The appropriate CPI for high thermal and lower RE performances should be selected. [ABSTRACT FROM AUTHOR]

This work delves deep into the exploration of Rare-earth (RE) replacement doping germanene monolayers, where RE elements stand out for their fascinating electronic and magnetic nature derived from the elusive f-orbitals. Employing density functional theory (DFT) calculations, we unveil the electronic and magnetic characteristics of doped germanene systems. With its two-dimensional honeycomb structure, germanene holds immense promise for a wide range of applications within group IV materials. Through the discussion, we deeply uncover how the substitution of two specific concentrations of RE-atoms, namely La, Ce, Pr, Nd, Sm and Pm, transforms semi-metallic non magnetic germanene to half-metallic ferromagnets with remarkably high critical temperatures, when Hubbard correction is considered. These revelations not only deepen our comprehension of integrating f-orbitals into germanene but also open up exciting avenues for advancements in spintronic devices and beyond. • Electronic and magnetic characteristics of RE replacement-doped germanene are explored. • Two concentrations of RE-atoms are considered for a comprehensive comparison. • Hubbard-term results in half-metallic ferromagnets with remarkably high critical temperatures. • La- and Ce-doped show a metallic and semi conductor character, respectively. • The results are crucial for applications such as spintronic next generation devices. [ABSTRACT FROM AUTHOR]

Although honeycomb is a kind of lightweight structural material with great potential, its specific strength is not always able to meet the requirements, especially in the weight-sensitive field. Inspired by the bionic idea of cuttlebone, the curved-wall configuration design is proposed to strengthen the buckling impedance of honeycomb, which can effectively prevent the premature occurrence of buckling failure mode induced by thin walls. Compared with the straight-wall honeycomb materials of the same geometric size, the probability of buckling failure in curved-wall honeycomb materials proposed in this paper is reduced by more than 22 %. Moreover, to achieve the preparation of curved-wall configuration, a processing strategy that uses stretching process to prepare ultralight carbon fiber honeycomb (Carbcomb) material is firstly introduced. Compared to the Hexcel Corporation's aluminum honeycomb with a density of 21 kg/m3, for the Carbcomb, the specific compressive strength and specific shear strength along both the L and W directions respectively improved by 57 %, 61 % and 77 %. In addition, the minimum density of fabricated Carbcomb (14.6 kg/m3) is less than that of the Hexcel's products (16 kg/m3), and the research findings fill the gap of the carbon fiber honeycomb material in low density areas (10 ∼ 30 kg/m3). More importantly, this process which does not require much manual operation can effectively avoid the problems of unstable mechanical properties, difficult mass production and high preparation cost of the existing carbon fiber structural parts. This curved-wall configuration design and fabricated approach widens the potential of carbon fiber honeycomb as a structural material, and makes it possible for lower cost and higher efficiency in aerospace and transportation applications. [ABSTRACT FROM AUTHOR]

Real-time thermal deformation monitoring plays a crucial role in calibrating phase signals and maintaining satellite performance for large spaceborne antennas. The inverse finite element method (iFEM) represents a promising shape-sensing methodology applicable to monitor the three-dimensional displacement of structures through surface-measured strain. However, the high-accuracy reconstruction of large-scale structures involves a large number of inverse elements, which leads to the low level of computational efficiency. To address this issue, a displacement-gradient-based variable-size iFEM is proposed in this paper. According to the characteristics of deformation, this method optimizes the size of each inverse element to reduce the number of inverse elements required, which improves real-time performance and maintains the high accuracy of reconstruction. The real-time performance of the proposed method is verified by conducting a simulation test on a large-scale honeycomb antenna. According to the simulation results, the variable-size iFEM is applicable to achieve the same accuracy of reconstruction using fewer inverse elements than conventional iFEM. An experimental test is performed and the optimal variable-size discretization that balances accuracy and efficiency is determined. The results show that the maximum error of reconstructed displacement is less than 7.3 % and the reconstruction time is in no excess of 0.1 s. [ABSTRACT FROM AUTHOR]

Tandem design is promising to improve the undesired compressive behavior of honeycomb for the long-stroke demand. Therefore, a novel tandem honeycomb, named tandem face-centered hierarchical honeycomb (TFCHH), is developed to achieve the perfect load-bearing process. The deformation mechanism of TFCHH is revealed by the compressive experiments, which dissipates energy by progressive folding and demonstrates a multi-stage plateau response. The numerical research is conducted to explore the compressive properties of TFCHH. It is observed that the energy absorption and load-bearing stability of TFCHH is 23.04 % and 38.24 % higher than those of integrated face-centered hierarchical honeycomb. To approach the perfect load-bearing behavior of TFCHH, the matching strategy of hierarchy order and relative density is investigated to fully exploit the compressive potential of hierarchical honeycomb components. As a result, the optimal load-bearing capacities of hierarchical honeycomb components with the hierarchy order from 1 to 3 are obtained when the relative densities are 16.6 %, 15.0 %, and 11.2 %. The customized design on the load-bearing behavior of TFCHH demonstrates that altering the stacking sequence can control the deformation sequence of hierarchical honeycomb components, and adjusting the composition proportion can tailor the effective stroke of the desired plateau stress. By establishing the theoretical relationship between the plateau force and configuration parameters, it is found that the load-bearing behavior of TFCHH is accurately predicted with the dynamic correction coefficient of 1.4. [Display omitted] • A face-centered hierarchical strategy is proposed to develop a novel tandem honeycomb. • The perfect load-bearing behavior is approached by the matching design of hierarchy order and relative density. • Multi-stage load-bearing behavior is customized by controlling the stacking sequence and composition proportion. • Theoretical relationship between multi-platform forces and structural parameters is established accurately. [ABSTRACT FROM AUTHOR]

• Honeycomb-structured S and N dual-doped graphene-like carbon (SNG) is prepared by low-temperature (850 °C) pyrolysis of S-doped carbon nitride with Mg. • Mg acts as a reducing agent for graphitizing the carbon precursor and as a precursor for new Mg 3 N 2 and MgS products, which play as pore-generating templates for honeycomb-like structure. • Rh/SNG catalyst outperforms state-of-the-art commercial Pt/C for hydrogen evolution reaction (HER) with an extremely lower overpotential of 13 mV at 10 mA cm−2 and outstanding stability. • High crystallinity, superior electrical conductivity, and hierarchically porous honeycomb structure of SNG doped with N and S are credited with this remarkable HER performance. State-of-the-art electrocatalysts are based on catalytically active metal deposited on conductive porous carbon. Herein, we report a new strategy of engineering of a honeycomb-structured S and N dual-doped graphene-like carbon (SNG) as a supporting material for Rh catalysts by a simple low-temperature (850 °C) pyrolysis of S-doped carbon nitride (S-CN) in the presence of Mg. Interestingly, here Mg plays a marvelous dual role not only as a reducing agent for graphitizing the S-CN but also as a precursor for new Mg 3 N 2 and MgS products, which play as pore-generating templates for honeycomb-like structures. This features highly robust graphitized carbon with excellent electrical conductivity, proper S and N content, and porosity, making it highly desirable as catalyst support. Supporting Rh (5.2 wt.%) on SNG outperforms state-of-the-art commercial Pt/C electrodes for hydrogen evolution reaction (HER) under alkaline settings (1.0 M KOH) with an extremely lower overpotential of 13 mV at 10 mA cm−2, a lower Tafel value, and a higher turnover frequency. In addition, Rh/SNG as the cathode for industrial water electrolysis in 6.0 M KOH electrolyte at 70 °C shows excellent performance with only 1.76 V cell to achieve 500 mA cm−2 and maintains long-term durability with negligible decay. The distinctive properties of SNG, including S and N dual doping, high graphiticity, superior electrical conductivity, and honeycomb-like hierarchical meso‑ and macropore structure, are credited with this remarkable HER performance. The S and N dopants in the SNG framework optimize the electronic structure of the Rh by synergistic interaction between them as illustrated by first-principal density functional theory calculations and electronic structure analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

• Hierarchical honeycomb panel absorbed 9.6% more energy, needing 4.8% more for perforation than AuxHex sandwich panel. • Front sheet failed through ductile shearing; core crushed, back sheet plugs detached after impact. • Back sheet deflection 12–15% higher, indicating longer contact and force disparity during impact. Honeycomb sandwich panels (HSPs) are extensively employed across various industries owing to their outstanding strength and capacity for energy absorption. Despite their widespread use, the potential of additively manufactured (AM) honeycombs in ballistic protection remains relatively unexplored. This study aims to comprehensively assess the energy absorption performance of two distinct HSP configurations, namely AuxHex and Hierarchical, through high-velocity impact tests spanning velocities ranging from 220 to 270 m/s. The high-velocity impact experiments are conducted using a single-stage pneumatic gun, complemented by simulations executed via Abaqus/Explicit. Our findings reveal that the hierarchical HSP demonstrated a notable 9.6 % enhancement in energy absorption compared to panels featuring an AuxHex honeycomb. Interestingly, the hierarchical panels also necessitated 4.8 % more energy for perforation. In terms of failure mechanisms, both sheets of the HSPs experienced ductile shearing, with the formation of characteristic petal-like structures. Concurrently, the honeycomb core underwent fragmentation on the side facing the projectile, while plugs were ejected from the back sheet. Moreover, our analysis indicates that the residual deflection of the back sheet surpassed that of the striking sheet by 15–20 %. This disparity can be attributed to prolonged contact duration and variations in interaction forces between the sheets. Overall, this investigation provides valuable insights into the energy absorption capabilities of AM honeycomb-based HSPs under high-velocity impact conditions, shedding light on their potential for enhanced ballistic protection in various applications. [ABSTRACT FROM AUTHOR]

• Bubble behavior and fluid distribution were studied in a honeycomb microreactor. • The complete breakup of bubbles benefits the fluid distribution uniformity. • The growth rate of pressure drop increases with U G due to the local pressure drop. • A new pressure drop correlation of honeycomb microreactor was developed. The bubble breakup dynamics and fluid distribution in a honeycomb microreactor with chemical reaction were visually investigated. The bubble split and collide behavior in multistage divergent-convergent branching structures were observed and studied. It was demonstrated that the bubble breakup at bifurcations relies dramatically on the collision behavior of the bubble pairs at the downstream convergence. Four bubble flow regimes were observed at the convergence: no collision, collision-slipping, squeezing-slipping, and blockage-slipping. The non-uniformity of the fluid distribution mainly stems from uneven breakup of bubbles at the upstream bifurcation, the lack of bubble breakup, the feedback effects of downstream and the manufacturing errors. Furthermore, the variation of pressure drop in a honeycomb microreactor was explored. The overall pressure drop was found to increase by the local pressure drop, whereas reduced with the increased absorption capacity of liquid phase. Taking these impact factors into account, a modified Lockhart-Martinelli pressure drop model was developed. [ABSTRACT FROM AUTHOR]

This research paper presents numerical and experimental investigations to examine the effectiveness of a honeycomb pattern as a form of the geometry of artificial roughness in solar air heaters. Utilizing Computational Fluid Dynamics (CFD) through three-dimensional simulations, the study explores how Thermo-Hydraulic Performance Parameter (THPP) is affected by variations in honeycomb geometry. The research examines various parameters, including the angle of attack (Ø), relative roughness pitch (P/e), and relative roughness height (e/D) within the respective ranges of (90°-120°), (8–12), and (0.03–0.05). The system's performance is evaluated across various flow scenarios, covering Reynolds numbers from (3000) to (21,000). Incorporating the honeycomb design into an absorber is observed to improve the heat transfer rates. The system achieves a maximum Nu of (140.65) at (e/D) of 0.04, (P/e) of 10, (Ø) of 120°, and Re of (21,000). The maximum FF of (0.039) was obtained at (e/D) of 0.05, (P/e) of 9, and (Ø) of 120° at a Reynolds number of (6000). The system exhibited a THPP of (1.7) at a Reynolds number of (6000). This Maximum THPP was associated with specific parameters, including (e/D) of 0.04, (P/e) of 10, and (Ø) of 120°. [Display omitted] • Numerical investigations followed by experimental validations. • Honeycomb-shaped artificial roughness improved the heat transfer rates. • The thermo-hydraulic performance parameter achieved a maximum value of (1.7). [ABSTRACT FROM AUTHOR]

• Ni 6 W 6 C/Co 2 O 3 @C composites are prepared from glucose, an eco-friendly material. • EAB can reach 7.12 GHz at the thickness of 2.04 mm and RL min is −56.68 dB at 5.43 GHz. • We designed absorber and the results showed that the microwave absorber can achieve an average EMW loss of more than 99 % in the 0.3–16.04 GHz frequency band and an average EMW loss in the 16.04–18 GHz frequency band is more than 90 %. In recent years, the synthesis of absorbing materials using green and environmentally friendly natural raw materials have become a research topic, but green and environmentally friendly materials with both high performance and simple synthesis steps still need to be developed. In this work, glucose and metal organic framework (MOF) were used to prepare composite materials with strong absorbing ability and low cost. We chose glucose, which is convenient to purchase on the market, as the raw material and constructed MOF derivatives with carbon shell skeleton nanostructures through a simple method of hydrothermal and annealing. Compared to the raw materials of traditional absorbing materials, glucose has environmentally friendly, low-cost and green characteristics. We characterized the microstructure and morphology of the material. In addition, we also analyzed the material composition and absorption mechanism of Ni 6 W 6 C/Co 2 O 3 @C. We have found from the theoretical analysis and simulation results of transmission lines that the minimum reflection loss (RL min) value of Ni 6 W 6 C/Co 2 O 3 @C material at 5.43 GHz and 4.76 mm is −56.68 dB. And the effective absorption bandwidth (EAB) at 2.04 mm can reach 7.12 GHz. We load the best sample to the honeycomb structure, a broadband microwave absorber was designed for simulation. The results show that the broadband microwave absorber can achieve an average electromagnetic wave (EMW) loss of more than 99 % in the 0.3–16.04 GHz frequency band (RL value is less than −20 dB), and an average EMW loss of more than 90 % in the 16.04–18 GHz frequency band (RL value less than −10 dB). The composite structure of glucose and MOF derivatives enhances the dielectric loss of the material and enriches various EMW loss mechanisms. Finally, a green, environmental-friendly, high-performance absorbing material with a simple synthesis method is prepared. These results provide insights into the research on EMW absorption of composite materials and new methods for referring. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ FZC honeycomb spheres for cellulase direct adsorption and immobilization. • ZIF-8 components of the carrier regulate secondary structure of cellulase. • Thermal activation of immobilized enzyme was reported. • Application of immobilized cellulase in biomass saccharification. This paper presents a promising heterogeneous biocatalyst-immobilized cellulase system, which can facilitate the targeted catalytic conversion of biomass to reducing sugars. Magnetic Zeolite Imidazole Framework-8/chitosan (Fe 3 O 4 /ZIF-8/CS, FZC) hybrid honeycomb microspheres were synthesized to immobilize cellulase using an in-situ growth strategy. The enhancement of immobilization efficiency induced by each constituent of the composite carrier was explored. This exploration was grounded in varying combinations of components within the honeycomb composite spheres, revealing the indispensability of ZIF-8. Through in-situ assembly, the composite material presents a microsphere with an internal honeycomb structure and multilevel pores. Effective immobilization, temperature-responsive conformational change, and cyclic stability were achieved due to the scaling effect of the channel, extensive specific surface area, and abundant amino group interactions enable immobilized enzymes to maintain excellent performance under challenging operating conditions, demonstrating an enhanced structure-performance relationship. With the obtained immobilized cellulase, we achieved a high load (461.67 mg/g) of cellulase and a significant reducing sugar yield (328.39 mg/g) from corncob waste. In addition, we investigated the enhancement effect of thermal activation on the immobilized enzyme activity of composite carrier. The results showed that the appropriate heat treatment was conducive to the activation of FZC immobilized enzyme with a reducing sugar yield 1.61 times higher than that of the control. The strategy provided in this study promotes the development of immobilized biocatalysts and provides a useful reference for the further design of biocatalytic systems. [ABSTRACT FROM AUTHOR]

• A novel composite auxetic reentrant honeycomb structure is designed and fabricated. • The one-stage light gas gun and diffuser-type shock tube were utilized to generate and propagate exponential decaying shock wave. • The effect of gradient form on impact resistance performance was experimentally and numerically investigated. • The effect of relative density of composite reentrant honeycomb structure was analyzed and investigated. The researches on dynamic responses of underwater impulsive loading have been conducted. However, the previous study mainly concentrated on metal sandwich structure and fixed supported boundary. The relative research on composite auxetic re-entrant honeycomb structure and simply supported boundary are rarely. In this paper, the effect of the gradient form and relative density on impact resistance performance of composite auxetic re-entrant honeycomb structure was experimentally and numerically investigated. The one-stage light gas gun was applied to provide initial kinetic energy of the fly plate, and the diffuser-type shock tube was utilized to generate and propagate exponential decaying shock wave. The pressure–time curve was respectively amplified and recorded by the charge amplifier and oscilloscope. The response speed, final deflection of rear panel and failure mode of cores and panels were used to evaluate impact resistance of composite auxetic re-entrant honeycomb structures. Moreover, acoustic-structure interaction algorithm was applied to simulate impact course of specimens in Abaqus/Explicit. The results between experiment and numerical simulation exhibited good consistency. The results indicated that the positive gradient form could excessively slow down response speed of rear panel by dissipating energy of shock wave, and the average gradient demonstrated smaller final displacement of rear panel and less failure compared with graded structures. [ABSTRACT FROM AUTHOR]

Unlike traditional energy dissipation structures that dissipate energy through irreversible plastic deformation or collapse, metamaterials based on friction energy dissipation have attracted attention due to their reusability. This article proposed a novel energy dissipation metamaterial by integrating friction energy dissipation mechanism into negative Poisson's ratio (NPR) structures. The integration of friction energy dissipation mechanism can simultaneously enhance the effective stiffness and NPR effect. The mechanical properties of the proposed structure were investigated using theoretical analysis, experiments, and finite element (FE) simulations. The influence of variables such as internal concave angle, friction coefficient, and number of reinforcing ribs was discussed. The results indicate that both unit cell and honeycomb structure can repeatedly dissipate energy within the elastic range. Compared with the traditional concave hexagonal structure, the effective stiffness and NPR effect were enhanced. This work provides a novel idea for the design of NPR energy dissipation structures. [ABSTRACT FROM AUTHOR]

Developing eco-friendly electromagnetic wave (EMW) absorption materials with simultaneous compression-resistant resilience, thermal insulation properties, and stability in complex environments is a formidable challenge. Inspired by the honeycomb structures, we utilized the concepts of directional freezing and carbonization to fabricated versatile P-doped hydrophilic carbon aerogel (CPA) for more demanding and complex applications. The numerous boundary-type defects generated by graphene nanosheets (GNs) and multi-walled carbon nanotubes (MWCNTs) on the surfaces of the honeycomb structure served as polarization centers, resulting in an effective absorption bandwidth (EAB) spanning from the C band to the Ku band (4–18 GHz, 1.0–4.0 mm) yielding a minimum reflection loss (RL, −72.02 dB) for CPA-800. The radar cross section (RCS) values of CPA-800 were below −15 dBm2 within the range of −90° < θ < 90°, possessing a strong radar wave attenuation capability for potential application in both air and underwater conditions. The thermal insulation performance of CPA-800 reduced the sample temperature from 300 °C to 63 °C, and possessed outstanding structural stability during prolonged and intense flame exposure. This work represents a novel multifunctional platform for EMW absorption, thermal insulation, and resilience materials in various harsh environments. [Display omitted] • P-doped hydrophilic carbon aerogels were fabricated using directional freezing and carbonization concepts. • The carbon aerogels exhibited outstanding EMW absorption performance covering C-band to Ku-band (4–18 GHz, 1–4 mm). • A novel multifunctional protective platform in various harsh electromagnetic, underwater, and thermal environments. [ABSTRACT FROM AUTHOR]

The fabrication of three-dimensional (3D) honeycomb carbon frameworks, incorporating embedded silicon (Si) nanoparticles (NPs), is successfully achieved through a facile method involving mixing, carbonization, and acid pickling. The as-prepared Si@PVPC composites exhibit excellent electrochemical performances due to reasons as follows. (1) Honeycomb channels supply enough space to accommodate the expansion of Si NPs and so structural integrity of 3D honeycomb carbon frameworks are maintained during lithiation/delithiation processes. (2) Honeycomb channels offers fast transfer paths for Li-ion diffusion. (3) 3D carbon frameworks afford reliable and stable electric contact points. As a result, Si@PVPC electrodes show a capacity of 1294.3 mAh g−1 at 2 A g−1 after 1400 cycles with a capacity retention of 85.5 %. Even at an ultrahigh current of 16 A g−1, Si@PVPC electrodes still show a capacity of 619.6 mAh g−1. The Si@PVPC composites with 3D honeycomb carbon frameworks were in-situ synthesized via gel preparation, carbonization and acid picking. The Si@PVPC composites exhibit excellent electrochemical performances due to the stable structure and fast transfer paths for charge and lithium ion. [Display omitted] • Nano-silicon embedded in 3D honeycomb carbon frameworks were in-situ fabricated. • 3D carbon frameworks facilitate the charge transfer and lithium-ion diffusion. • Carbon frameworks show structure integrity. • Long cycle life with a capacity of about 1290 mAh g−1 at 2 A g−1 over 1400 cycles. [ABSTRACT FROM AUTHOR]

Achieving broad effective absorption bandwidth (EAB) with minimal weight gain in aramid honeycomb (HC) remains a significant challenge. This study successfully prepared crosslinked PVA/RGO foam in situ-filled aramid HC composites using freeze-drying and low-temperature chemical reduction processes. By adjusting the GO content, partial to complete encapsulation of the PVA framework by RGO sheets could be achieved, and all samples exhibited a dense framework network structure as seen in the SEM. The PVA@0.4GO/0.4Vc foam filled HC achieves a broadband EAB of 12.74 GHz at a thickness of 30 mm. Such foam samples can also achieve effective absorption at 1.19–2 GHz. The foam filled honeycomb further increases the compressive strength to 5.24 MPa compared with pure HC. Obvious overlap between the CST electric field distribution demonstrates that the conductive loss and λ/4 interference cancels are the main pathways of MA. Overall, the PVA/RGO foam-filled HC composites exhibit ultra-broadband microwave absorption performance with enhanced structural compressive strength, which has significant feasibility and application value in aerospace stealth structures. [Display omitted] • The honeycomb structure allows for broadband microwave absorption and enhanced structural strength. • The PVA@0.4GO/0.4Vc foam achieve a broadband effective absorption performance of 12.74 GHz at 30 mm. • The electromagnetic parameters of PVA@GO foam can be precisely controlled. • The PVA@GO filled honeycomb were expected to be used for aviation stealth based on the light weight and broadband properties. [ABSTRACT FROM AUTHOR]