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Pulsed electric field (PEF) pretreatment has been shown to improve the quality of dried fruits in terms of antioxidant activity and bioactive compounds. In this study, apricots were pretreated with PEF at different field strengths (0.7 kV/cm; 1.2 kV/cm and 1.8 kv/cm) at a frequency of 50 Hz, and electric pulses coming in every 20 µs for 30 s, prior to freeze−drying and air−drying treatments. PEF treatments were carried out at different field strengths. The impact of different pretreatments on the quality of dried apricot was determined in terms of physical properties, antioxidant activity, total phenolic content, and metabolite profile. PEF pretreatments significantly (p < 0.05) increased firmness of all the air−dried samples the most by 4–7−fold and most freeze−dried apricot samples (44.2% to 98.64%) compared to the control group. However, PEF treatment at 1.2 kV/cm did not have any effect on hardness of the freeze−dried sample. The moisture content and water activity of freeze−dried samples were found to be significantly lower than those of air−dried samples. Scanning electron microscopy results revealed that air drying caused the loss of fruit structure due to significant moisture loss, while freeze drying preserved the honeycomb structure of the apricot flesh, with increased pore sizes observed at higher PEF intensities. PEF pretreatment also significantly increased the antioxidant activity and total phenol content of both air−dried and freeze−dried apricots. PEF treatment also significantly (p < 0.05) increased amino acid and fatty acid content of air−dried samples but significantly (p < 0.05) decreased sugar content. Almost all amino acids (except tyrosine, alanine, and threonine) significantly increased with increasing PEF intensity. The results of this study suggest that PEF pretreatment can influence the quality of air−dried and freeze−dried apricots in terms antioxidant activity and metabolites such as amino acids, fatty acids, sugar, organic acids, and phenolic compounds. The most effective treatment for preserving the quality of dried apricots is freeze drying combined with high−intensity (1.8 kv/cm) PEF treatment. [ABSTRACT FROM AUTHOR]

Honeycomb sandwich structures are widely used in lightweight applications. Usually, these structures are subjected to extreme loading conditions, leading to potential failures due to delamination and debonding between the face sheet and the honeycomb core. Therefore, the present study is focused on the mechanical characterisation of honeycomb sandwich structures fabricated using advanced 3D printing technology. The continuous carbon fibres and ONYX-FR matrix materials have been used as raw materials for 3D printing of the specimens needed for various mechanical characterization testing; ONYX-FR is a commercial trade name for flame retardant short carbon fibre filled nylon filaments, used as a reinforcing material in Morkforged 3D printer. Edgewise and flatwise compression tests have been conducted for different configurations of honeycomb sandwich structures, fabricated by varying the face sheet thickness and core cell size, while keeping the core cell thickness and core height constant. Based on these tests, the proposed structure with face sheet thickness of 3.2 mm and a core cell size of 12.7 mm exhibited the highest energy absorption and prevented delamination and debonding failures. Therefore, 3D printing technology can also be considered as an alternative method for sandwich structure fabrication. However, detailed parametric studies still need to be conducted to meet various other structural integrity criteria related to the lightweight applications. [ABSTRACT FROM AUTHOR]

The high variability of shock in terrorist attacks poses a threat to people's lives and properties, necessitating the development of more effective protective structures. This study focuses on the angle gradient and proposes four different configurations of concave hexagonal honeycomb structures. The structures' macroscopic deformation behavior, stress-strain relationship, and energy dissipation characteristics are evaluated through quasi-static compression and Hopkinson pressure bar impact experiments. The study reveals that, under varying strain rates, the structures deform starting from the weak layer and exhibit significant interlayer separation. Additionally, interlayer shear slip becomes more pronounced with increasing strain rate. In terms of quasi-static compression, symmetric gradient structures demonstrate superior energy absorption, particularly the symmetric negative gradient structure (SNG-SMS) with a specific energy absorption of 13.77 J/cm³. For dynamic impact, unidirectional gradient structures exhibit exceptional energy absorption, particularly the unidirectional positive gradient honeycomb structure (UPG-SML) with outstanding mechanical properties. The angle gradient design plays a crucial role in determining the structure's stability and deformation mode during impact. Fewer interlayer separations result in a more pronounced negative Poisson's ratio effect and enhance the structure's energy absorption capacity. These findings provide a foundation for the rational design and selection of seismic protection structures in different strain rate impact environments. [ABSTRACT FROM AUTHOR]

This paper introduces a new type of flexible rudder surface based on the cosine-type zero Poisson's ratio honeycomb to enhance the adaptive capabilities of aircraft and enable multi-condition, rudderless flight. The zero Poisson's ratio honeycomb structure exhibits exceptional in-plane and out-of-plane deformation capacities, as well as a high load-bearing capability. To investigate the deformation characteristics of flexible rudder surfaces utilizing cosine honeycomb structures, this study undertakes a comprehensive investigation through finite element simulation and 3D printing experiments. Moreover, this study analyzed the impact of honeycomb parameters and layout on the deflection performance and weight. The flexible rudder surface, fabricated from nylon, achieves smooth and consistent chordwise bending deformation, as well as uniform spanwise deformation within a tolerance of ±25°, and the maximum equivalent stress observed was 31.99 MPa, which is within the material's allowable stress limits (50 MPa). Finite element simulation results indicate that once the deflection angle of the rocker exceeds 15°, a discernible deviation arises between the actual deflection angle of the flexible control surface and that of the rocker. Furthermore, this deviation escalates with increasing rocker rotation angles, and this discrepancy can be mitigated by augmenting the number of cosine honeycomb cells within the flexible rudder surface. Finally, a prototype of the flexible rudder surface was successfully produced using 3D printing technology, and the experimental results confirmed the deformation behavior, aligning with simulation outcomes with a deviation of less than 20%. These findings confirm the effective deflection performance of the designed flexible rudder surface, highlighting its potential application in small unmanned aerial vehicles. [ABSTRACT FROM AUTHOR]

Auxetic lattice structures are three-dimensionally designed intricately repeating units with multifunctionality in three-dimensional space, especially with the emergence of additive manufacturing (AM) technologies. In aerospace applications, these structures have potential for use in high-performance lightweight components, contributing to enhanced efficiency. This paper investigates the design, numerical simulation, manufacturing, and testing of three-dimensional (3D) star-shaped lattice structures with tailored mechanical properties. Finite element analysis (FEA) was employed to examine the effect of a lattice unit's vertex angle and strut diameter on the lattice structure's Poisson's ratio and effective elastic modulus. The strut diameter was altered from 0.2 to 1 mm, while the star-shaped vertex angle was adjusted from 15 to 90 degrees. Laser powder bed fusion (LPBF), an AM technique, was employed to experimentally fabricate 3D star-shaped honeycomb structures made of Ti6Al4V alloy, which were then subjected to compression testing to verify the modelling results. The effective elastic modulus was shown to decrease when increasing the vertex angle or decreasing the strut diameter, while the Poisson's ratio had a complex behaviour depending on the geometrical characteristics of the structure. By tailoring the unit vertex angle and strut diameter, the printed structures exhibited negative, zero, and positive Poisson's ratios, making them applicable across a wide range of aerospace components such as impact absorption systems, aircraft wings, fuselage sections, landing gear, and engine mounts. This optimization will support the growing demand for lightweight structures across the aerospace sector. [ABSTRACT FROM AUTHOR]

Auxetic structures, with re-entrant (inverted hexagonal or bow tie) unit cells, have received considerable interest due to their negative Poisson's ratio property that results in superior mechanical properties. This study proposes a simple method to create non-homogeneous re-entrant honeycombs by modifying the size of chevron crosslinks. The various structural designs were conceived by changing the geometrical dimensions of the crosslinks, namely the length ( l c l ) and the thickness ( t c l ), while maintaining the parameters of the re-entrant cell walls. The influence of the design parameters of chevron crosslinks on the mechanical behaviour of additively manufactured re-entrant honeycombs was investigated experimentally and numerically. The structures were fabricated using the Fused Deposition Modelling (FDM) technique from polylactic acid (PLA) plastic. In-plane quasi-static compression tests were conducted to extract the elastic, plastic, and densification properties of the structures. Furthermore, a Finite Element (FE) model was developed via LS-DYNA R11.0 software, validated experimentally, and was then used to obtain a deeper insight into the deformation behaviour and auxetic performance of various designs. The obtained results revealed that the mechanical performance of re-entrant honeycombs can only be tuned by controlling the geometrical configuration of chevron crosslinks. [ABSTRACT FROM AUTHOR]

The statistical mechanical behavior of weakly nonlinear multimoded optical settings has been attracting increased interest over the last few years. The main purpose of this work is to numerically investigate the main factors that affect the thermalization process in photonic lattices. In particular, we find that lattices with identically selected properties (such as temperature, coupling coefficient, lattice size, and excitation conditions) can exhibit very different thermalization dynamics and, thus, thermalization distances. Our investigation is focused on two different two-dimensional lattices: the honeycomb lattice and the triangular lattice. Our numerical results show that, independently of the excitation conditions, the honeycomb lattice always thermalizes faster than the triangular lattice. We mainly explain this behavior by the quasilinear spectrum that promotes wave-mixing in the honeycomb lattice in comparison to the power-like spectrum of the triangular lattice. In addition, we investigate the combined effects of temperature as well as the sign and magnitude of the nonlinearity. Switching either the sign of the Kerr nonlinear coefficient or the sign of the temperature can lead to significant differences in the thermalization dynamics, a phenomenon that can be physically explained in terms of wave instabilities. Larger absolute values of the temperature |T| result in more uniform distributions for the power occupation numbers and faster thermalization speeds. Finally, as expected, increasing the magnitude of the nonlinearity results in accelerated thermalization. Our findings provide valuable insights into optical thermalization in discrete systems, where experimental realization may bring about new possibilities for light manipulation and applications. [ABSTRACT FROM AUTHOR]

This research delves into the design, modeling, and finite element impact analysis of the segmented sandwich composite armor system subjected to impact loading, considering different parameters such as materials to be used, armor height, and armor design configuration. Initial studies were performed to select the ideal model that will provide the best impact resistance at the least weight and with minimal fabrication requirements. Material type, thickness, and overall model configuration were defined during the initial model development period. Once the final design was defined, finite element analysis was performed using 2017 ABAQUS software to observe the performance of the model and to validate the efficiency of the chosen armor. Based on the results from the material selection and thickness validation, the optimal design with the best impact resistance was noted as 1.2 mm thick rectangular segmented silicon carbide tiles, serving as the top layer that covers the three-level gradient core composed of a titanium metal honeycomb frame filled with silicon carbide inserts, and finally a 2 mm thick glass epoxy composite layer made from four laminas in a 0/45/90/-45-degree configuration serving as the last layer of the armor. [ABSTRACT FROM AUTHOR]

The application of bionic structures for the design of energy-absorbing structures has been proposed recently. The rapid advancement of additive manufacturing technology provides technical support for the fabrication of non-traditional structures and further improves the energy-absorbing properties of bionic structures. This work proposes a novel bionic hybrid structure that consists of honeycomb-inspired thin-walled tubes filled with weevil-inspired diamond TPMS (triple periodic minimal surface) structures. The energy-absorbing properties and the deformation behaviors of these topologies under axial crushing loads were investigated using combined numerical simulations and experimental tests. First, the effect of filling quantity and filling distribution on energy absorption of the hybrid structures was investigated. Results show that honeycomb tubes and diamond TPMS structures produce a synergistic effect during compression, and the hybrid structures exhibit excellent stability and energy absorption capacity. The bionic hybrid structure improves specific energy absorption (SEA) by 299% compared to honeycomb tubes. Peak crush force (PCF) and SEA are more influenced by filling quantity than by filling distribution. The effects of diamond TPMS structure volume fraction and honeycomb tube wall thickness on the energetic absorptive capacity of the hybrid structure were furthermore investigated numerically. Finally, a multi-objective optimization method was used to optimize the design of the bionic hybrid structure and balance the relationship between crashworthiness and cost to obtain a bionic hybrid energy-absorbing structure with superior performance. This study provides valuable guidelines for designing and fabricating lightweight and efficient energy-absorbing structures with significant potential for engineering applications. [ABSTRACT FROM AUTHOR]

This study explores the development of a terramechanics-based model for non-pneumatic tire–terrain interaction, focusing on different spoke designs. The research investigates how four spoke shapes (honeycomb, modified honeycomb, re-entrant honeycomb, and straight spokes) affect non-pneumatic tire performance in off-road conditions. Using the finite element method (FEM) to model non-pneumatic tires, and smoothed-particle hydrodynamics (SPH) to model dry, loose soil, simulations were conducted to replicate real-world loading conditions. This study utilizes virtual environment solution finite element analysis software to examine the interaction between a non-pneumatic tire and dry, loose soil, with a focus on calculating longitudinal and vertical forces. These forces play a pivotal role in determining the motion resistance coefficient. The results show distinct variations in the motion-resistance coefficients among the spoke designs on dry, loose soil. This analysis helps to identify the spoke configurations that optimize energy efficiency and fuel consumption. By comparing and evaluating the four spoke designs, this study shows the effect of spoke design on tire motion resistance. This study concluded that the modified honeycomb spoke design is the most stable and the least sensitive to operating conditions. [ABSTRACT FROM AUTHOR]

Honeycomb lung is a radiological manifestation of various lung diseases, seriously threatening patients' lives worldwide. In clinical practice, the precise localization of lesions and assessment of their severity are crucial. However, accurate segmentation and grading are challenging for physicians due to the heavy annotation burden and diversity of honeycomb lungs. In this paper, we propose a multitask learning architecture for semi-supervised segmentation and grading diagnosis to achieve automatic localization and assessment of lesions. To the best of our knowledge, this is the first method that integrates a grading diagnosis task into honeycomb lung semi-supervised segmentation. Firstly, we adapt cross-learning to capture local features and long-range dependencies from the CNN and transformer. Secondly, considering the diversity of honeycomb lung lesions, the shape-edge aware constraint is designed to assist the model in locating lesions. Then, in order to better understand the different levels of information in the images, we develop global contrast and local contrast learning to enhance the model's learning of semantic-level and pixel-level features. Lastly, aiming to improve the diagnostic accuracy, we propose a gradient thresholding algorithm to integrate the segmentation predictions into the grading diagnosis network. The experiment's results based on the in-house honeycomb lung dataset demonstrate the superiority of our method. Compared to other methods, our approach achieves a state-of-the-art performance. In particular, in external data testing, our predictions are consistent with physicians in the majority of cases. In addition, the segmentation results based on the public Kvasir-SEG dataset also indicate that our method has good generalization ability. [ABSTRACT FROM AUTHOR]

Honeycomb structures have attracted much attention for their excellent characteristics of reducing vibration and noise in recent years. In this study, through band analysis of different ligament structures, we aim to optimize the design of a steel structure that can isolate most of the noise in the 1500–5000 Hz range. The present study examines several different chiral structures. We calculate the band gaps of chiral structures under different geometric configurations and identify the variations in band gaps with geometric layouts. It is found that compared to other chiral structures, the triligaments chiral structure exhibits excellent band gap characteristics. The calculation results demonstrate that enhancing axial symmetry while filling central nodes can effectively enhance the structure's band gap properties. Frequency–response functions of different lattice structures are computed, and the results align with the calculations of band structures. This study then analyzes the influence of the number of periods on the magnitude of vibration attenuation, revealing that under the same number of periods, the wider the band gap of the structure, the greater the vibration attenuation. Both the triligaments chiral structure and the vertical triligaments structure possess ideal band gap widths, effectively suppressing wave propagation. Subsequently, harmonic response analyses and transient wave calculations further validate the accuracy of the band structure and frequency–response curve calculations. Our study results provide a new way to design a sound insulation structure that can isolate noise signals within the frequency range from 1500 to 5000 Hz in engineering. [ABSTRACT FROM AUTHOR]

Additive manufacturing enables the production of lattice structures, which have been proven to be a superior class of lightweight mechanical metamaterials whose specific stiffness can reach the theoretical limit of the upper Hashin–Shtrikman bound for isotropic cellular materials. To achieve isotropy, complex structures are required, which can be challenging in powder bed additive manufacturing, especially with regard to subsequent powder removal. The present study focuses on the Finite Element Method simulation of 2.5D anisotropic plate lattice metamaterials and the investigation of their lightweight potential. The intentional use of anisotropic structures allows the production of a cell architecture that is easily manufacturable via Laser Powder Bed Fusion (LPBF) while also enabling straightforward optimization for specific load cases. The work demonstrates that the considered anisotropic plate lattices exhibit high weight-specific stiffnesses, superior to those of honeycomb structures, and, simultaneously, a good de-powdering capability. A significant increase in stiffness and the associated surpassing of the upper Hashin–Shtrikman bound due to anisotropy is achievable by optimizing wall thicknesses depending on specific load cases. A stability analysis reveals that, in all lattice structures, plastic deformation is initiated before linear buckling occurs. An analysis of stress concentrations indicates that the introduction of radii at the plate intersections reduces stress peaks and simultaneously increases the weight-specific stiffnesses and thus the lightweight potential. Exemplary samples illustrate the feasibility of manufacturing the analyzed metamaterials within the LPBF process. [ABSTRACT FROM AUTHOR]

The rapid development of additive manufacturing (AM) has facilitated the creation of bionic lightweight, energy-absorbing structures, enabling the implementation of more sophisticated internal structural designs. For protective structures, the utilization of artificially controlled deformation patterns can effectively reduce uncertainties arising from random structural damage and enhance deformation stability. This paper proposed a bionic corrugated lightweight honeycomb structure with controllable deformation. The force on the onset state of deformation of the overall structure was investigated, and the possibility of controlled deformation in the homogeneous structure was compared with that in the corrugated structure. The corrugated structures exhibited a second load-bearing capacity wave peak, with the load-bearing capacity reaching 60.7% to 117.29% of the first load-bearing peak. The damage morphology of the corrugated structure still maintained relative integrity. In terms of energy absorption capacity, the corrugated lightweight structure has a much stronger energy absorption capacity than the homogeneous structure due to the second peak of the load carrying capacity. The findings of this study suggested that the combination of geometric customization and longitudinal corrugation through additive manufacturing offers a promising approach for the development of high-performance energy-absorbing structures. [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]

We use elastic and inelastic neutron scattering (INS) to study the antiferromagnetic (AF) phase transitions and spin excitations in the two-dimensional (2D) zig-zag antiferromagnet FePSe3. By determining the magnetic order parameter across the AF phase transition, we conclude that the AF phase transition in FePSe3 is first-order in nature. In addition, our INS measurements reveal that the spin waves in the AF ordered state have a large easy-axis magnetic anisotropy gap, consistent with an Ising Hamiltonian, and possible biquadratic magnetic exchange interactions. On warming across TN, we find that dispersive spin excitations associated with three-fold rotational symmetric AF fluctuations change into FM spin fluctuations above TN. These results suggest that the first-order AF phase transition in FePSe3 may arise from the competition between C3 symmetric AF and C1 symmetric FM spin fluctuations around TN, in place of a conventional second-order AF phase transition. [ABSTRACT FROM AUTHOR]

Stereolithography has been used to create ceramic parts with complex geometry that is difficult to achieve with conventional fabrication techniques. This study used stereolithography to print silica honeycomb structures with a commercial Formlabs Form2 printer. The printed samples were sintered at different temperatures, and the print shape was retained up to 1300°C, but significant distortion from partial melting occurred at 1400°C. Higher sintering temperatures lead to more shrinkage, but it is non‐uniform among directions, with the open cell plane shrinking more than the dense plane of the sample. As expected, the density of samples also increases with the sintering temperature. At higher sintering temperatures, there is an increase in cristobalite and a decrease in quartz, tridymite, and amorphous silica. Regarding mechanical properties, the out‐of‐plane compressive strength is approximately one order of magnitude higher than the in‐plane compressive strength. When compressed along the out‐of‐plane direction, the samples sintered at lower temperatures surprisingly exhibit higher strength, which is explained by the micro‐cracking mechanism. As expected, the samples sintered at higher temperatures display higher strength when compressed along the in‐plane direction. [ABSTRACT FROM AUTHOR]

A modified 3D re-entrant honeycomb is designed and fabricated utilizing Laser Cladding Deposition (LCD) technology, the mechanical properties of which are systematically investigated by experimental and finite element (FE) methods. Firstly, the influences of honeycomb angle on localized deformation and the response of force are studied by an experiment. Experimental results reveal that the honeycomb angles have a significant effect on deformation and force. Secondly, a series of numerical studies are conducted to analyze stress characteristics and energy absorption under different angles (α) and velocities (v). It is evident that two variables play an important role in stress and energy. Thirdly, response surface methodology (RSM) and the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) are implemented with high precision to solve multi-objective optimization. Finally, the final compromise solution is determined based on the fitness function, with an angle of 49.23° and an impact velocity of 16.40 m/s. Through simulation verification, the errors of energy absorption (EA) and peak crush stress (PCS) are 9.26% and 0.4%, respectively. The findings of this study offer valuable design guidance for selecting the optimal design parameters under the same mass conditions to effectively enhance the performance of the honeycomb. [ABSTRACT FROM AUTHOR]

Nomex honeycomb composites (NHCs) are commonly used in various industrial sectors such as aerospace and automotive sectors due to their excellent material properties. However, when machining this type of structure, problems can arise due to significant cutting forces and unwanted cell vibrations. In order to remedy these shortcomings, this study proposes to integrate RUM (rotary ultrasonic machining) technology, which consists of applying ultrasonic vibrations along the axis of rotation of the cutter. To fully understand the milling process by ultrasonic vibrations of the NHC structure, a 3D numerical finite element model is developed using Abaqus/Explicit software. The results of the comparative analysis between the components of the simulated cutting forces and those from the experiment indicate a close agreement between the developed model and the experimental results. Based on the developed numerical model, this study comprehensively analyzes the influence of the ultrasonic vibration amplitude on various aspects, such as stress distribution in the cutting zone, chip size, the quality of the machined surface and the components of the cutting force. Ultimately, the results demonstrate that the application of ultrasonic vibrations leads to a reduction of up to 50% in the components of the cutting force, as well as an improvement in the quality of the machined surface and a reduction in the size of chips. [ABSTRACT FROM AUTHOR]

Machining of Nomex honeycomb composite (NHC) structures is of critical importance in manufacturing parts to the specifications required in the aerospace industry. However, the special characteristics of the Nomex honeycomb structure, including its composite nature and complex geometry, require a specific machining approach to avoid cutting defects and ensure optimal surface quality. To overcome this problem, this research suggests the adoption of RUM technology, which involves the application of ultrasonic vibrations following the axis of revolution of the UCK cutting tool. To achieve this objective, a three-dimensional finite element numerical model of Nomex honeycomb structure machining is developed with the Abaqus/Explicit software, 2017 version. Based on this model, this research examines the impact of vibration amplitude on the machinability of this kind of structure, including cutting force components, stress and strain distribution, and surface quality as well as the size of the chips. In conclusion, the results highlight that the use of ultrasonic vibrations results in an important reduction in the components of the cutting force by up to 42%, improves the quality of the surface, and decreases the size of the chips. [ABSTRACT FROM AUTHOR]

This work investigates the mechanical behavior under out-of-plane compression of the Al core and honeycomb sandwich at increasing temperatures of up to 300 °C. After the first introductive theoretical modeling on room-temperature compressive behavior, the experimental results at increasing temperatures up to 300 °C are presented and discussed. The analysis of the results shows that peak stress, plateau stress, and specific absorbed energy gradually decrease as the temperature increases. The final densification occurs always at the same strain level (around 75%). Sandwich honeycomb test temperatures have been limited to 200 °C for bonding problems of the skin to the sandwich due to the glue. The experimental and modeling results agree well at room temperature as well at increasing temperatures. The results can provide useful information to choose base materials for greater energy absorption at increasing temperatures. [ABSTRACT FROM AUTHOR]

This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast load. Each of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/fiber. The exterior is supported by a Kerr elastic foundation with three characteristics. The key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each layer. In contrast to previous first-order shear deformation theories, no shear correction factor is required. Navier's exact solution was used to treat the double-curved shell problem with a single title boundary, while the finite element technique and an eight-node quadrilateral were used to address the other boundary requirements. To ensure the accuracy of these results, a thorough comparison technique is employed in conjunction with credible statements. The problem model's edge cases allow for this kind of analysis. The study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive loads. In addition, this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads. [ABSTRACT FROM AUTHOR]

The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties, utilizing an impedance tube setup in accordance with ASTM standard E 1050-12. The Creality Ender-3, a 3D printer, was used for printing the honeycomb structures, and polylactic acid (PLA) material was employed for their construction. The organic, inorganic, and polymeric compounds within the composites were identified using fourier transformation infrared (FTIR) spectroscopy. The structure and homogeneity of the samples were examined using a field emission scanning electron microscope (FESEM). To determine the sound absorption coefficient of the 3D printed honeycomb structure, numerous samples were systematically developed using central composite design (CCD) and analysed using response surface methodology (RSM). The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient (NRC). The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black, 1.025 wt% aluminium powder, and 3.151 mm distance between parallel edges. Overall, the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields, including defence and aviation, where lightweight and acoustic properties are of great importance. [ABSTRACT FROM AUTHOR]

Displacement mapping is a computer graphics technique that enables the design of components with regularly or randomly textured surfaces that can be quickly materialized on a three-dimensional (3D) printer when needed. This approach is, in principle, more flexible, faster, and more economical compared to conventional texturing methods, but the accuracy of the texture depends heavily on the parameters used. The purpose of this study is to demonstrate how to produce a surface-textured part using polygonal (mesh) modeling software and a photopolymerizable resin and to develop a universal methodology to predict the dimensional accuracy of the model file log combined with a resin 3D printer. The printed components were characterized on a scanning confocal microscope. In the setup used in this study, the mesh size had to be reduced to 10% of the smallest feature size, and the textured layer had to be heavily (×4.5) overexposed to achieve the desired accuracy. As a practical application, two functional stamps with a regular (honeycomb) and a random texture, respectively, were successfully manufactured. The insights gained will be of great benefit for quickly and cost-effectively producing components with innovative patterns and textures for a variety of hobby, industrial, and biomedical applications. [ABSTRACT FROM AUTHOR]

Hollow structures reduce weight without compromising load-bearing capacity and are widely used. The new Glass-Fiber-Reinforced Polymer high-strength thin-walled inner mold simplifies internal cavity construction and boosts structural performance. This study first investigates the influence of a GFRP high-strength thin-walled circular tube on the cross-sectional load-carrying capacity of hollow slabs. Then, a formula for the bending load-carrying capacity of the section under the action of the tube is derived. The results indicate that when the height of the concrete compression zone meets certain conditions, GFRP high-strength thin-walled circular tubes can improve the ultimate load-carrying capacity of the hollow floor slabs. In order to achieve a more economical design, the bending moment modification of a GFRP high-strength thin-walled circular tube of a continuous slab was studied. Research has found that the bending moment modulation limit for a continuous slab is 35.65% when it is subjected to a load of P u = 24   k N . Experimental analysis has shown that the results are generally consistent with the calculations. In practical engineering, the application of a GFRP high-strength thin-walled circular tube of continuous slabs has limitations. Therefore, this study investigated a GFRP high-strength thin-walled honeycomb core slab and found that its ultimate load-bearing capacity is greater compared to waffle slabs. In addition, the stress performance of the GFRP high-strength thin-walled honeycomb core internal mold is superior, making it more promising for practical applications. [ABSTRACT FROM AUTHOR]

The dynamic mechanical behavior and cushioning performance of honeycomb sandwich panels, which are extensively employed in product cushioning packaging due to their exceptional energy absorption capabilities, were examined using a combination of experimental and numerical methods. Several factors, such as maximum acceleration–static stress, cushioning coefficient–static stress, and other curves, were analyzed under various impact conditions. The simulated stress–strain, deformation modes, cushioning coefficients, and other parameters demonstrate consistency with the experimental results. The acceleration, maximum compression, and cushioning coefficient obtained from the experiment and simulation calculation were 30.68 g, 15.44 mm, and 2.65, and 31.96 g, 14.91 mm, and 2.79, respectively. The results indicate that all error values were less than 5%, confirming the precision and reliability of the model. Furthermore, the model was utilized to simulate and predict the cushioning performance of honeycomb sandwich panels with different cell structures and paper thicknesses. These results provide a solid basis for enhancing the design of subsequent honeycomb element structures. [ABSTRACT FROM AUTHOR]

Two-dimensional black phosphorus (2D BP) has attracted significant research interest in the field of biomedical applications due to its unique characteristics, including high biocompatibility, impressive drug-loading efficiency, phototherapeutic ability, and minimal side effects. However, its puckered honeycomb lattice structure with lone-pair electrons of BP leads to higher sensitivity and chemical reactivity towards H2O and O2 molecules, resulting in the degradation of the structure with physical and chemical changes. In our study, we synthesize polyethylene glycol (PEG) and glutathione-stabilized doxorubicin drug-assembled Au nanoparticle (Au-GSH-DOX)-functionalized BP nanosheets (BP-PEG@Au-GSH-DOX) with improved degradation stability, biocompatibility, and tumor-targeting ability. Transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy indicate the nanoscale degradation behavior of synthesized nanoconjugates in three different environmental exposure conditions, and the results demonstrate the remarkable nanoscale stability of BP-PEG@Au-GSH-DOX against the degradation of BP, which provides significant interest in employing 2D BP-based nanotherapeutic agents for tumor-targeted cancer phototherapy. [ABSTRACT FROM AUTHOR]

A non-pneumatic tire (NPT) overcomes the shortcomings of a traditional pneumatic tire such as wear, punctures and blowouts. In this respect, it shows great potential in improving driving safety, and has received great attention in recent years. In this paper, a carbon fiber-reinforced polyethylene terephthalate (PET/CF) honeycomb is proposed as a support structure for NPTs, which can be easily prepared using 3D printing technology. The experimental results showed that the PET/CF has high strength and modulus and provides excellent mechanical properties. Then, a finite element (FE) model was established to predict the compression performance of auxetic honeycombs. Good agreement was achieved between the experimental data and FE analysis. The influence of the cell parameters on the compressive performance of the support structure were further analyzed. Both the wall thickness and the vertically inclined angle could modulate the mechanical performance of the NPT. Finally, the application of vertical force is used to analyze the static load of the structure. The PET/CF honeycomb as the support structure of the NPT showed outstanding bearing capacity and stiffness in contrast with elastomer counterparts. Consequently, this study broadens the material selection for NPTs and proposes a strategy for manufacturing a prototype, which provides a reference for the design and development of non-pneumatic tires. [ABSTRACT FROM AUTHOR]

Background: Androgenetic alopecia, the most common cause of non-scarring hair loss, is a consequence of the gradual miniaturization of the hair follicles. In the majority of male androgenetic alopecia cases, a patient's history and clinical evaluation may be sufficient to establish the diagnosis, while for women, they should be supplemented with trichoscopy. Methods: The PubMed and Scopus databases were used to collate published studies and to analyze the most typical trichoscopic findings in patients diagnosed with androgenetic alopecia. A total of 34 articles were retrieved after exclusion. Results: The most common features identified using trichoscopy included hair diameter variability (94.07% of patients), vellus hairs (66.45%) and the peripilar sign (43.27%). Others, such as the honeycomb pattern, yellow and white dots, were less relevant. Conclusions: We concluded that hair diameter variability, vellus hairs and the peripilar sign represented valuable indicators for the diagnosis of androgenetic alopecia. [ABSTRACT FROM AUTHOR]

The membrane-type structure that can achieve excellent sound insulation characteristics under lightweight conditions is widely concerned, but it generally involves a small mass block attached to a thin membrane. Although this kind of design can obtain better acoustic insulation performance, the mass block will cause installation and manufacturing issues in industrial applications. This paper presents a multilayer honeycomb membrane-type acoustic metamaterial with an interlayer structure. Similar to the mass block, the interlayer structure makes less sound energy transmitted by varying the eigenmode characteristics of the membrane. Considering the integrated design of the interlayer structure, the issues of installation and manufacturing are solved and the sound transmission loss is enhanced on the fixed overall dimension and small additional mass. The results indicate that the design of interlayer structures can break the bottleneck of ultrathin and lightweight requirements. Meanwhile, the symmetry of interlayer position can lead to the shift in transmission loss valley to a higher frequency, achieving high sound insulation in a wide frequency range. [ABSTRACT FROM AUTHOR]

This study aims to explore the potential application of hollow glass beads (HGB) compounded with graphene oxide (GO, HGB@GO) to improve the mechanical properties of rigid polyurethane foam (RPUF). This HGB@GO/RPUF composite is considered a potential filler for reinforcing aluminum honeycomb (AH). A characterization of the chemical structure and surface morphology of HGB@GO was conducted, as well as the analysis of its effect on the compression properties of the foam. The compressive strength of HGB@GO/RPUF (4 wt. %) is 146.17% higher than that of pure RPUF. This study also compared the deformation modes of AH and foam-filled honeycomb (F-AH) structure under axial crushing. The interaction effects between the foam and AH were also analyzed. The results indicated that the RPUF improves the compressive capacity and deformation stability of the AH through its good compression properties and interaction with the aluminum foil. The use of HGB@GO/RPUF further enhances the energy absorption characteristics of the F-AH. In comparison with the pure RPUF-AH, the total and specific energy absorption of the HGB@GO/RPUF (4 wt. %)-AH increase by 74.65% and 44.98%, respectively. This work demonstrates that the prepared HGB@GO can enhance the mechanical properties of RPUF, and HGB@GO/RPUF-AH is expected to be a desirable energy-absorbing device. [ABSTRACT FROM AUTHOR]

The primary reason for the decrease in power output from the PV array is partial shading. During partial shading conditions (PSCs) PV modules experience a mismatch in current and voltage generated. Also, the power voltage (P–V) characteristics of the PV array possess multiple peaks under PSCs. To mitigate the effects caused by PSCs, the configuration of the PV array is the finest solution. This paper proposes a novel Reduced Cross Tied (RCT) configuration to enhance maximum power output from a symmetrical PV array under PSCs. The RCT configuration has fewer cross-ties compared to the TCT configuration and is applicable to a square array of any size. The proposed RCT configuration along with conventional configurations such as Total Cross Tied (TCT), Series–Parallel, Bridge-Link, and Honey-Comb are validated in simulation and hardware for 7 × 7 and 8 × 8 symmetrical PV arrays under Short and Narrow (SN), Short and Wide (SW), Long and Narrow (LN) and Long and Wide (LW) shading patterns. A comparative analysis is done between the proposed configuration and conventional configurations in terms of mismatch loss (ML), fill factor, efficiency (η ), Wiring Loss, and Global Maximum PowerPoint (GMPP). The proposed RCT configuration is able to achieve GMPP equal to the TCT configuration under the LN shading pattern and on par with the TCT configuration under SN, SW, and LW shading patterns. RCT-configured PV array possesses a minimum reduction of 25% in wiring loss for any array size. RCT configuration applies to a square array of any size.The results replicate the efficacy of the proposed RCT configuration compared to existing configurations. [ABSTRACT FROM AUTHOR]

A honeycomb structure is a sandwich structure widely used in fuselage, among which the hexagonal honeycomb core is the most widely used. The energy absorption characteristics and impedance ability of the structure are the main reasons that directly affect the energy absorption characteristics of the honeycomb sandwich structure. Therefore, it is necessary to study the out-of-plane mechanical properties of the composite honeycomb sandwich structure. Based on the numerical simulation results, the energy absorption characteristics of several composite honeycomb sandwich structures are verified by drop hammer impact experiments. The research shows that the transient energy absorption characteristics of the composite honeycomb sandwich structure are mainly related to the cell size of the honeycomb structure. The smaller the size of the front cell, the stronger the overall impact resistance; the strength of the composite honeycomb sandwich structure exceeds that of 7075 aluminum alloy-NOMEX and carbon fiber-NOMEX honeycomb sandwich structures. In this paper, the energy absorption characteristics of composite honeycomb sandwich structures under different impact energy are compared and studied. The displacement, force and energy curves of energy absorption characteristics related to time variables are analyzed. The difference in protective performance between the composite honeycomb sandwich structure and existing airframe structure is compared and studied. The optimal structural design parameters of composite honeycomb sandwich under low-speed impact of drop hammer are obtained. The maximum energy absorption per unit volume of the designed honeycomb sandwich structure is 171.7% and 229.8% higher than that of the NOMEX-AL and NOMEX-C structures. The 6.4 mm and 3 mm cell sizes show good characteristics in high-speed buffering and crashworthiness. The composite honeycomb sandwich airframe structure can improve the anti-damage performance of the UAV airframe structure, ensure the same thickness and lightweight conditions as the existing honeycomb sandwich airframe structure, and improve the single-core bearing mode of the existing airframe structure. [ABSTRACT FROM AUTHOR]

Sharp-bending waveguide is a key element for ultra-compact and densely integrated photonic devices, which is promising to enlarge the capability of modern information processing in a single chip. Topological photonics manifest the nature of robust propagation against sharp bending and such robustness has been experimentally demonstrated in topological integrated interfaces. It is important to quantify the bending loss of topological interface but has remained exclusive. In this work, we report on the characterization of sharp-bending robustness in the integrated topological interface of valley photonic crystals (VPCs) by experimentally quantifying the ultralow bending loss. The VPCs are designed on a standard silicon-on-insulator platform with the inversion-symmetry broken in honeycomb lattice, and four types of topological interfaces can be constructed by two topologically-distinct VPCs. As one of the representative cases, zigzag-AA interface is applied to demonstrate the robust propagation along sharp bending. In experiment, we fabricate a series of VPC interfaces with different turn number and the same transmission distance, which perform the ultralow bending loss less than 0.02 dB per 120-deg turning. Furthermore, we experimentally characterize the propagation loss in the integrated interfaces. Our approach not only shows the ability of VPC topological interfaces to suppress backscattering stemming from sharp bending, but also paves the way for topological nanophotonic dense integration. [ABSTRACT FROM AUTHOR]

Sandwich structures are often used as protective structures on ships. To further improve the energy-absorbing characteristics of traditional honeycomb sandwich structures, an energy-absorbing mechanism is proposed based on the gradient folding deformation of lotus root nodes and a leafy stem vein homogenizing load mechanism. A honeycomb sandwich structure is then designed that combines lotus root nodes and leafy stem veins. Four types of peak-nest structures, traditional cellular structure (TCS), lotus root honeycomb structure (LRHS), leaf vein honeycomb structure (LVHS), and lotus root vein combined honeycomb structure (LRVHS), were prepared using 3D printing technology. The deformation modes and energy absorption characteristics of the four honeycomb structures under quasistatic action were investigated using a combination of experimental and simulation methods. It was found that the coupling design improved the energy absorption in the structural platform region of the LRHS by 51.4% compared to that of the TCS due to its mechanical mechanism of helical twisting and deformation. The leaf vein design was found to enhance the peak stress of the structure, resulting in a 4.84% increase in the peak stress of the LVHS compared to that of the TCS. The effects of the number, thickness, and position of the leaf vein plates on the honeycomb structure were further explored. The greatest structural SEA effect of 1.28 J/g was observed when the number of leaf vein plates was four. The highest SEA of 1.36 J/g was achieved with a leaf vein plate thickness of 0.6 mm, representing a 7.3% improvement compared to that of the 0.2 mm thickness. These findings may provide valuable insights into the design of lightweight honeycomb sandwich structures with high specific energy absorption. [ABSTRACT FROM AUTHOR]

A method for measuring the resistive characteristics of channels in the blanks of microchannel plates was developed. Two probes were used for measurements, which minimized leakage currents through adjacent channels. The resistive properties of single channels of the microchannel insert in the reduced blank of MCP 18-10 were studied. It was established that the resistance of the channels depends on their position in the microchannel honeycomb. It was shown that the channels located in close proximity to the monolithic frame have less resistance compared to those located in the middle of a multicore glass honeycomb. [ABSTRACT FROM AUTHOR]

In response to the shortcomings of concentrated stress, difficult forming, and short service life of commonly used honeycomb ceramic thermal storage materials with square lattice holes, the author has developed a new type of low stress honeycomb ceramic thermal storage material by studying the structure, forming mold, and extrusion forming material of the thermal storage body. The author introduced the changes in specific surface area and porosity of heat storage materials with different geometric structures, and analyzed and compared the structural characteristics of two types of heat storage materials, namely heat storage balls and honeycomb bodies, under the premise of equal heat storage capacity. The trajectory of air-flow in the heat storage chamber was simulated using CFD software, and the pressure loss and centerline velocity changes of different shapes of honeycomb were analyzed. The flow characteristics, pressure distribution, and heat transfer performance of gas inside different shapes of honeycomb were calculated. The experimental results showed that the closer to the circular shape, the smaller the pressure loss of the centerline. The larger the equivalent diameter, the smaller the resistance along the path. From the perspective of cold pressure loss alone, regular quadrilateral holes and regular circular holes are the best choices for the shape of honeycomb openings. The centerline velocity of the equilateral triangle hole is the largest, indicating that the smaller the equivalent diameter is, the greater the average velocity at the outlet is. The resistance along the path of the round hole is the smallest, the regular quadrilateral hole is slightly larger, and the pressure loss of the equilateral triangle hole is the largest, which exceeds the round hole by nearly 1/3. Taking into account factors such as heat storage, specific surface area, flow characteristics, and heat transfer characteristics, quadrilateral honeycomb cells are the best choice. [ABSTRACT FROM AUTHOR]

In this study, the graded hierarchical hexagonal honeycomb (GHHH) integrating gradient design and hierarchical design was fabricated using the 3D-printing technique, and its in-plane elastic properties were investigated theoretically, experimentally, and numerically. Theoretical solutions were developed based on the Euler beam theory to predict the effective elastic modulus and Poisson's ratio of GHHH, and theoretical values were in good agreement with the experimental and numerical results. The effect of gradient design and hierarchical design on the in-plane elastic properties of GHHH was also analyzed and compared. Results showed that the hierarchical design has a more significant effect on Poisson's ratio and adjusting the internal forces of GHHH compared with the gradient design. In addition, it was found that GHHH exhibited higher stiffness compared with regular hexagonal honeycomb (RHH), graded hexagonal honeycomb (GHH), and vertex-based hierarchical hexagonal honeycomb (VHHH) under the constraint of the same relative density, respectively. Specifically, the effective elastic modulus of GHHH can be enhanced by 119.82% compared to that of RHH. This research will help to reveal the effect of integrating hierarchical design and gradient design on the in-plane elastic properties of honeycombs. [ABSTRACT FROM AUTHOR]

Downhole drilling tool vibration measurement is crucial for drilling exploration safety, so real-time monitoring of vibration data is required. In this research, a honeycomb triboelectric nanogenerator (H-TENG) capable of adapting to various downhole environments is proposed. It can measure the frequency of downhole drilling equipment's vibrations and transfer mechanical energy to electrical energy for use in powering other low power downhole meters. In order to preliminarily verify the possibility of sensors used for vibration measurement of downhole drilling tools, we built a simulated vibration platform to test the sensing performance and vibration energy collection performance of H-TENG. According to the testing results, the measurement range of vibration frequency and amplitude are 0 to 11 Hz and 5 to 25 mm, respectively, and the corresponding measurement errors are less than 5% and 6%, respectively. For vibrational energy harvesting, when four sensors are wired in series with a 107 resistance, the maximum power is approximately 1.57 μW. Compared to typical methods for measuring downhole vibration, the honeycomb triboelectric nanogenerator does not need an external power source, it has greater reliability and output power, and it can vary its shape to adapt to the complicated downhole environment. In addition, the H-TENG can be combined freely according to the diameter of the drill string, and even if one sensor unit is damaged, the other units can still be used normally. [ABSTRACT FROM AUTHOR]

In order to further study the cushioning performance of concave hexagonal cores (CHCs) and expand their application range, the in-plane finite element model of CHCs is established in this paper. A dynamic cushioning coefficient method was proposed to characterize the cushioning performance of CHCs. The dynamic cushioning coefficient curve and minimum dynamic cushioning coefficient (MDCC) of CHCs with different impact velocities and structural parameters are obtained. The influence rules of structural parameters and impact velocities on the MDCC are analyzed; the deformation mode and transformation empirical formula are also obtained. The results show that when other parameters are constant, the MDCC of CHCs decreases with the increase of impact velocity, increases with the increase of wall thickness and side length ratio, and decreases with the increase of expansion angle. The theoretical analysis is consistent with the finite element results, which further verifies the reliability of the model. This paper provides a solid theoretical basis for the industrial application of the cushioning performance of CHCs and forms a key technical support. [ABSTRACT FROM AUTHOR]

Materials properties are determined by their compositions and structures. In ABO3 oxides different cation orderings lead to mainly perovskite‐ or corundum like derivatives with exciting physical properties. Sometimes, a material can be stabilized in more than one structural modification, providing a unique opportunity to explore structure‐properties relationship. Here, CoVO3 obtained in both ilmenite‐(CoVO3‐I) and LiNbO3‐type (CoVO3‐II) polymorphs at moderate (8–12 GPa) and high pressures (22 GPa), respectively are presented. Their distinctive cation distributions affect drastically the magnetic properties as CoVO3‐II shows a cluster‐glass behavior while CoVO3‐I hosts a honeycomb zigzag magnetic structure in the cobalt network. First principles calculations show that the influence of vanadium is crucial for CoVO3‐I, although it is previously considered as non‐magnetic in a dimerized spin‐singlet state. Contrarily, CoVO3‐II shows two independent interpenetrating antiferromagnetic Co‐ and ferromagnetic V‐hcp sublattices, which intrinsically frustrate any possible magnetic order. CoVO3‐II is also remarkable as the first oxide crystallizing with the LiNbO3‐type structure where both metals contain free d electrons. CoVO3 polymorphs pinpoint therefore as well to a much broader phase field of high‐pressure A‐site Cobaltites. [ABSTRACT FROM AUTHOR]

Through the method of numerical simulation, the detection rules of different defect characteristics and the detection effect of detection process parameters on different defects were explored. The optimal detection process parameters for GFRP/NOMEX honeycomb sandwich structure specimens with delaminating, debonding, water accumulation, and glue plugging defects were obtained. Experimental research was carried out to verify its detection effect for actual tests. The result is that the technology under this parameter can get better defect detection effect. [ABSTRACT FROM AUTHOR]

In order to improve the impact resistance of sandwich panels under low-velocity impact, the lotus leaf vein is selected as a biological prototype to design a bio-inspired honeycomb (BIH) sandwich panel. ABAQUS is used to establish and effectively verify the finite element (FE) model of the BIH sandwich panel. To systematically compare and study the mechanical properties of BIH and conventional hexagonal honeycomb sandwich panels under low-velocity impact, the maximum displacement of face-sheets, the deformation mode, the plastic energy consumption and the dynamic response curve of the impact end are presented. At the same time, the performance differences between them are revealed from the perspective of an energy absorption mechanism. Furthermore, the influence of the circumscribed circle diameter ratio of the BIH trunk to branch (γ), the thickness ratio of the trunk to branch (K) and the impact angle (θ) on impact resistance is studied. Finally, the BIH sandwich panel is further optimized by using the response surface method. It can be concluded that, compared to conventional hexagonal honeycomb sandwich panels, the addition of walls in the BIH sandwich panel reduces the maximum deformation of the rear face-sheet by 10.29% and increases plastic energy consumption by 8.02%. Properly adjusting the structural parameters can effectively enhance the impact resistance of the BIH sandwich panel. [ABSTRACT FROM AUTHOR]

Triply periodic minimal surfaces (TPMSs) have demonstrated significant potential in lattice structure design and have been successfully applied across multiple industrial fields. In this work, a novel lattice structure with tunable anisotropic properties is proposed based on two typical TPMS types, and their mechanical performances are studied both experimentally and numerically after being fabricated using a polymer 3D printing process. Initially, adjustments are made to the original TPMS lattice structures to obtain honeycomb lattice structures, which are found to possess significant anisotropy, by utilizing numerical homogenization methods. Based on this, a continuous self-twisting deformation is proposed to change the topology of the honeycomb lattice structures to largely tune the mechanical properties. Quasi-static compression experiments are conducted with different twisting angles, and the results indicate that self-twisting can affect the mechanical properties in specific directions of the structure, and also enhance the energy absorption capacity. Additionally, it mitigates the risk of structural collapse and failure during compression while diminishing structural anisotropy. The proposed self-twisting strategy, based on honeycomb lattice structures, has been proven valuable in advancing the investigation of lattice structures with largely tunable mechanical properties. [ABSTRACT FROM AUTHOR]

Based on the model of magnonic crystals (MCs) with honeycomb structure, we propose another model of two-dimensional MCs with honeycomb–kagome structure that is a periodic magnetic composite system composed of Fe, Co, or Py ferromagnetic cylindrical scatterers arranged in the EuO matrix as the honeycomb–kagome structure. The band structures of magnons in these systems are studied numerically by using the plane-wave expansion method. The results show that the Dirac points of magnons will be generated at the Brillouin region points if the scatterers are close-packed, that is to say, the edges of cylindrical scatterers are in contact with each other. The frequency of Dirac points can be indirectly adjusted by changing the radius ratio of close-packed cylinders. In addition, in the case of a large difference in the radius between the close-packed cylindrical scatterers, there will be a magnonic flat band in the band structure, which is a phenomenon of so-called compact localized states different from the impurity state in the crystal, and it is formed by the highly interference superposition of spin waves in the honeycomb–kagome structure. The research on the generation and modulation of magnonic Dirac points and flat bands not only expands the research content of condensed matter topological physics but also provides a promising platform for the application of artificial MCs in the fabrication of spin-wave topological devices. [ABSTRACT FROM AUTHOR]

Reactor design requires safety studies to ensure that the reactors will behave appropriately under incidental or accidental situations. Safety studies often involve multiphysics simulations where several branches of reactor physics are necessary to model a given phenomenon. In those situations, it has been observed that the neutron transport part is still a bottleneck in terms of computational times, with more than 80% of the total time. In the case of hexagonal lattice reactors, transport solvers usually invert the discretised Boltzmann equation by discretising the regular hexagon into lozenges or triangles. In this work, we seek to reduce the computational burden of the neutron transport solver by designing a numerical spatial discretisation scheme that would be more appropriate for honeycomb meshes. In our past research efforts, we have set up interesting discretisation schemes in the finite element setting in 2D, and we wish to extend them to 3D geometries that are prisms with a hexagonal base. In 3D, a rigorous method was derived to shrink the tensor product between 2D and 1D bases to minimum terms. We have applied these functions successfully on a reactor benchmark—Takeda Model 4—to compare and contrast the numerical results in a physical setting. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes (GPEs) have high safety and excellent electrochemical performance, so applying GPEs in lithium batteries has received much attention. However, their poor lithium ion transfer number, cycling stability, and low room temperature ionic conductivity seriously affect the utilization of gel polymer electrolytes. This paper successfully synthesized flexible poly (vinylidene fluoride-hexafluoropropylene)–lithium titanium aluminum phosphate (PVDF-HFP-LATP) gel polymer electrolytes using the immersion precipitation method. The resulting GPE has a porous honeycomb structure, which ensures that the GPE has sufficient space to store the liquid electrolyte. The GPE has a high ionic conductivity of 1.03 ×10−3 S cm−1 at room temperature (25 °C). The GPE was applied to LiFePO4/GPE/Li batteries with good rate performance at room temperature. The discharge specific capacity of 1C was as high as 121.5 mAh/g, and the capacity retention rate was 94.0% after 300 cycles. These results indicate that PVDF-HFP-LATP-based GPEs have the advantage of simplifying the production process and can improve the utility of gel polymer lithium metal batteries. [ABSTRACT FROM AUTHOR]

We present a new setup for resonant inelastic hard x-ray scattering at the Bernina beamline of SwissFEL with energy, momentum, and temporal resolution. The compact R = 0.5 m Johann-type spectrometer can be equipped with up to three crystal analyzers and allows efficient collection of RIXS spectra. Optical pumping for time-resolved studies can be realized with a broad span of optical wavelengths. We demonstrate the performance of the setup at an overall ∼180 meV resolution in a study of ground-state and photoexcited (at 400 nm) honeycomb 5d iridate α-Li2IrO3. Steady-state RIXS spectra at the iridium L3-edge (11.214 keV) have been collected and are in very good agreement with data collected at synchrotrons. The time-resolved RIXS transients exhibit changes in the energy loss region <2 eV, whose features mostly result from the hopping nature of 5d electrons in the honeycomb lattice. These changes are ascribed to modulations of the Ir-to-Ir inter-site transition scattering efficiency, which we associate to a transient screening of the on-site Coulomb interaction. [ABSTRACT FROM AUTHOR]

Optical properties of two-dimensional bilayer silicon have been explored at midinfrared wavelengths using density functional theory. In this work, progressive atomic structural deformation and the resultant variations in the optical properties of the bilayer silicon films were investigated under external in-plane strain. A phase transformation of the atomic structure has been observed at an applied in-plane tensile strain of 5.17%, at which the atomic lattice is changed from a low buckled to a buckle-free honeycomb structure. Evaluations of the optical properties were carried out by taking into account the inter- and intraband transitions. An abrupt change in the optical refraction index was observed at the phase transition. In addition, the buckle-free honeycomb structure presents a strain-resistive absorption edge pinned at 1.14 μm wavelength. Exceeding a strain threshold of 12.26% results in the development of both direct- and indirect-energy bandgap openings. The direct bandgap induced interband optical transitions, resulting in absorption peaks at midinfrared wavelengths and a drastic increase in the refraction index. Moreover, by adjusting the strain, the optical absorptions can be tuned in a wide range of wavelength at midinfrared from 1.5 to 11.5 μm. [ABSTRACT FROM AUTHOR]

In this work, the roller-shaped double V-wing honeycomb (DVWH) structure was used as the object, which was designed for forest harvesting machines. The deformation characteristics of its rotation under a specific compression were studied during the feeding process for the steel feeding roller used in the traditional combined harvesting machine for trees, which is prone to damaging the wood. The compression rate (10%–15%) and rotational speed (100 mm/s–320 mm/s) were used to analyze the relationship between compression rate, rotational speed, and deformation characteristics. The deformation characteristics, characterized by equivalent stress, radial displacement sensitivity, and energy absorption efficiency, were analyzed. The results show that the deformation characteristics of the roller-shaped DVWH structure under driven mode were more sensitive to compression rate and less sensitive to changes in rotational speed. There was a positive correlation between the equivalent stress of the node and the compression rate. The peak equivalent stress of the outermost node at 10% and 15% compression rates were 111.9 MPa and 230.9 MPa. There was a negative correlation between radial displacement–compression sensitivity and compression rate, and a decrease in radial displacement–compression sensitivity from 10% to 15% compression rate at different nodes ranges from 5% to 22%. The feed performance efficiency (EF) grew from 8.3% to 12.7% for a 1% increase in compression rate. [ABSTRACT FROM AUTHOR]