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The problem of optimization of the honeycomb wall structure of pipes subjected to static loads is investigated. As the basic engineering design parameter of the pipes, their ring rigidity is assumed. The corresponding optimization problem is formulated. Starting from the necessary ring rigidity of cylindrical pipes made of polymeric materials with honeycomb walls, their geometrical, physicomechanical, and technological parameters are determined. Based on the calculations, the optimum geometry (wall thickness, diameter, and the number of layers) of the pipes is found. Numerical results are presented and analyzed. [ABSTRACT FROM AUTHOR]

More than 110,000,000 tons of mismanaged plastics were to be produced in 2020. Polymers are favored in the preparation of thermally conductive materials due to their excellent comprehensive properties. However, most polymers fabricated for thermally conductive materials are difficult to degrade in the natural environment. To alleviate the increasingly severe environmental problems, we reported a novel eco-friendly material with high thermal conductivity, which was composited of chitosan microspheres (CSM) and hydroxyl-functionalized hexagonal boron nitride (OH-h-BN) nanoplatelets. Utilizing their significant difference in scales, the OH-h-BN nanoplatelets were arranged between each CSM. Their overall structure was similar to the honeycomb: CSM were honeycomb cores, and OH-h-BN nanoplatelets were honeycomb network. The routine-structure OH-h-BN/CS nanocomposites were only 0.94 ± 0.02 W·m−1·K−1 at 50 wt% in thermal conductivity. However, the OH-h-BN/CSM nanocomposites with honeycomb structure can reach 5.66 ± 0.32 W·m−1·K−1 in the same loading, for enhancement of 502% and 1914% than OH-h-BN/CS nanocomposites and pure CS, respectively. [Display omitted] • Chitosan microspheres (CSM) were reported as the substrate for heat conduction. • OH-h-BN/CSM nanocomposites possess the particular honeycomb network structures. • The thermal conductivity of OH-h-BN/CSM nanocomposites can reach 5.66 W·m−1·K−1. [ABSTRACT FROM AUTHOR]

In order to efficiently evaluate and design honeycomb structures with excellent energy-absorbing ability, in-plane dynamic response and multi-objective optimization of negative Poisson's ratio (NPR) honeycomb structures with sinusoidal curve are performed in this work. By establishing the in-plane impact finite element model, the deformation modes and in-plane dynamic responses of the sinusoidal NPR honeycomb structures under different impact velocities are detailed studied. And the geometric parameters (e.g., the amplitude and period) of the sinusoidal curve that affect the energy absorption performance of the structure are analyzed. Combining the optimal latin hypercube design method with the double-points infilling criterion, the high-precision adaptive Kriging models of the peak crush force (PCF) and the specific energy absorption (SEA) with respect to the amplitude and period are constructed. And then, a multi-objective crashworthiness optimization is carried out by non-dominated sorting genetic algorithm (NSGA-II). The Pareto optimal solution set is gained and the final compromise solution is then obtained based on the fitness function. The optimized results show the PCF of the sinusoidal NPR honeycomb structure decreases by 30.53%, while the SEA increases by 38.55%. It indicates that the optimized sinusoidal honeycomb structure has better energy absorption performance than the conventional concave hexagonal honeycomb. The results can provide some important design guidance for other honeycomb energy-absorbing structures. [ABSTRACT FROM AUTHOR]

To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, honeycomb ordered polycarbonate films were fabricated using water droplets as templates. The influencing factors including humidity, concentration, temperature and the solvent properties are investigated. The results show that the polycarbonate films with highly ordered structures can be obtained from CHCl3 or CH2Cl2 solution under certain condition. The pore size and the patterns can be regulated by the influencing factors. On the other hand, the honeycomb patterns cannot be formed using tetrahydrofuran as solvent. The polycarbonate films with ordered structures have many potential applications in electronics, optics etc. [Copyright &y& Elsevier]

Almost for forty years honeycomb structures have been used and probably are going to be used in the aviation due to their advantages. The main reason for being popularly used in the aircraft structure is its low weight ratio in comparison with solid structures. In this article, the historical perspective of honeycomb structures is briefly viewed and given an example to show why the honeycomb structures are preferred in structures. Then the sub elements which occur the honeycomb are described, the production techniques of them are given. In the last section of the article, some applications in the industry are given. [ABSTRACT FROM AUTHOR]

On the basis about studying free bending for box beam with rectangular cross-section filled by honeycomb core, supplementary displacements and stresses of restrained bending for such beam were analyzed. The hypothesis for separated variables was adopted to solve displacement. According to this, three aspect equations of geometrical, physical and balance were obtained. With Galerkin's method, it is summed up as two-order ordinary differential equations with the attenuation character. Analysis makes clear that attenuation speed of stress is concerned with a big load or a small one, geometric dimensions of cross-section of beam, and physical parameter of material. [ABSTRACT FROM AUTHOR]

Differential equation of restrained torsion for rectangular-section box bar with honeycomb core was established and solved by using the method of undetermined function. Non-dimension normal stress, shear stress acting in the faceplate and shear stress acting in the honeycomb-core and warping displacement were deduced. Numerical analysis shows the normal stress attenuates quickly along x-axis. Normal stress acting on the cross section at a distance of 20 h from the fixed end is only one per cent of that acting on the fixed end. [ABSTRACT FROM AUTHOR]

• Rubber-based composite films with different heterogeneous architectures were achieved. • Honeycomb structure Ti 3 C 2 T x /NR composite films were obtained after DCP curing. • Vulcanization treatment is more conducive to the enhancement of EMI shielding. • Mechanical properties of the crosslinked composite films were accordingly increased. The high performance Ti 3 C 2 T x MXene/natural rubber (NR) composite films with brick–mortar and honeycomb structure are successfully fabricated by a facile pressured-extrusion filtration process and the subsequent curing treatment. The microstructure of the Ti 3 C 2 T x MXene/NR composite films with heterogeneous architectures changed from brick-mortar to honeycomb structures after vulcanization reaction. The brick–mortar structure Ti 3 C 2 T x /NR composite film possesses superior EMI shielding performance with the shielding effectiveness (SE) of 57.1 dB and excellent mechanical properties of a tensile strength of 28.5 MPa. It's interesting to note that both EMI shielding and mechanical properties of the composite films with honeycomb structure showed significant improvement after curing process compared with those of brick–mortar counterparts, which exhibit the ultrahigh EMI SE of 63.5 dB and optimal mechanical tensile strength of 39.5 MPa. We believe that this work will provides a new idea for the production of high-performance rubber-based EMI shielding materials. [ABSTRACT FROM AUTHOR]

In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50–500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2) is a widely used biomaterial. It is a great challenge to confer antibacterial and antithrombotic properties to TiO 2 while maintaining its cell affinity. Here, we developed a new strategy to achieve the above goal by comprehensively controlling the chemical cues and geometrical cues of the surface of TiO 2. Using colloidal etching technology and UV irradiation treatment, we obtained the photofunctionalized nano-micro-honeycomb structured TiO 2. The honeycomb structured increased the photocatalytic activity of TiO 2 , which endowed TiO 2 with photo-induced superhydrophilicity to inhibit bacterial adhesion. The high photocatalytic activity also induced the strong photocatalytic oxidation of TiO 2 surface organic adsorbates to suppress fibrinogen and platelet attachment. In addition, owing to the micropore trapping-isolation effect on the bacteria and the nano-frames' contact guidance effect on the growth and spreading of platelet pseudopods, the honeycomb structure also shows a considerable inhibiting effect on bacterial and platelet adhesion. Therefore, due to the controlled chemical and geometrical cues' synergistic effect, the photo-functionalized TiO 2 honeycomb structure shows excellent bacterial-adhesion resistance and antithrombotic properties. More importantly, the photo-functionalized TiO 2 honeycomb did not inhibit the adhesion and growth of endothelial cells (ECs) after culturing for 3 d, indicating a good cell affinity that the traditional antifouling surfaces do not possess. [Display omitted] • TiO 2 honeycomb structures with micro-pores and nano-frames were fabricated. • TiO 2 Honeycomb showed improved antibacterial/ anticoagulant ability and cell affinity. • Photofunctionalized TiO 2 honeycomb showed excellent antibacterial/ anticoagulant ability and good cell affinity. • The synergistic effect of photofunctionalized TiO 2 and honeycomb structure on bacterial, platelets, and cells' adhesion was discussed. [ABSTRACT FROM AUTHOR]

Since brittle intermetallic compounds can form during soldering of nickel-based alloys, the microhardness in the area of the solder material is increased. This can be observed when joining thin-walled honeycomb structures. They are used as stationary component in sealing systems of gas turbine engines. Both the increase in the microhardness and the volume fraction of the solder material are assumed to threaten the integrity of the rotating sealing component if contact (rubbing) between the two components occurs during engine operation. To predict the impact of the solder material on the structure-property relationship of the nickel-based honeycomb structure, a micromechanical modelling approach is presented in this work. The three-dimensional micromechanical modelling approach comprises a composite of two distinct materials, the cell-wall and the solder material. The constitutive behaviour of the ductile cell-wall material is modelled with a crystal plasticity approach. A purely elastic material behaviour is assumed for the brittle solder material. For an efficient simulation, the investigated domain is restricted to the unit cell of the honeycomb composite. The studies show that with increasing volume fraction of the solder material, both thermal and mechanical loads of the honeycomb composite increase significantly, raising the likelihood of damage to the material of the rotating sealing component. [ABSTRACT FROM AUTHOR]

Cellular solids are known to exhibit size effects, i. e. differences in the apparent effective elastic moduli, when the specimen size becomes comparable to the cell size. The present contribution employs direct numerical simulations (DNS) of the mesostructure to investigate the influences of porosity, shape of pores, and thus material distribution along the struts, and orientation of loading on the size effects and effective moduli of regular honeycomb structures. Beam models are compared to continuum models for simple shear, uniaxial loading and pure bending of strips of finite width. It is found that the honeycomb structure exhibits a considerable anisotropy of the size effects and that honeycomb structures with circular pores exhibit considerably stronger size effects than those with hexagonal pores (and thus straight struts). Positive (stiffening) size effects are observed under simple shear and negative (softening) size effects under bending and uniaxial loading. The negative size effects are interpreted in terms of the stress-gradient theory • Systematic study of size effects in honeycomb structures under shearing, uniaxial loading and bending. • Comparison between beam models and fully resolved structures. • Considerable influence of pore shape on size effect. • Anisotropic size effects. • Interpretation of negative size effects in terms of stress-gradient theory. [ABSTRACT FROM AUTHOR]

Surface engineering of polymeric membranes can induce subtle changes in membrane properties and enhance their performance. Numerous membrane surface modification methods have been developed to improve the material performance. However, these methods can be complex, thus limiting their practical applications. Herein, we present a simple method for fabricating membranes with honeycomb surfaces by controlling the polymer molecular weight (M w). Spirobisindane-based intrinsically microporous poly(ether-ether-ketone) (iPEEK-SBI) homopolymers with low and high M w s were synthesized and used to prepare organic solvent nanofiltration (OSN) membranes. The significant effects of polymer M w on its physical properties, membrane morphology, and OSN performance were systematically investigated. iPEEK showed excellent solution processability, high Brunauer–Emmett–Teller surface area, and remarkable thermal stability. Three mechanically flexible OSN membranes exhibiting honeycomb surfaces with different honeycomb cell sizes were prepared using iPEEK-SBI homopolymers with low M w s at concentrations of 27–39 wt% in N -methyl-2-pyrrolidone. By contrast, the use of iPEEK-SBI homopolymers with high M w s yielded membranes with flat surfaces. The M w cutoffs of the membranes were fine-tuned in the range of 408–772 g mol−1 by adjusting the dope solution concentration. Although the M w cutoffs were unaffected by polymer M w , the membranes derived from the polymer with low M w exhibited substantially higher solvent permeance (18%–26%) than that of the high M w membrane prepared at the same dope solution concentration. Stable performance was demonstrated over seven days of continuous cross-flow filtration and a six-month aging of the membranes. This work shows the importance of surface engineering for OSN membranes by adjusting polymer M w. These findings open a new avenue for fine-tuning the properties of OSN membranes. Image 1 • Membranes prepared using intrinsically microporous poly(ether-ether-ketone). • Polymer molecular weight affects physical properties and membrane morphology. • Flat vs. honeycomb membrane surfaces studied via computational fluid dynamics. • Dope solution concentration affects honeycomb structure and Feret diameter. • Honeycomb surface demonstrate high thermal stability and stable performance. [ABSTRACT FROM AUTHOR]

• Thermo-mechanical buckling analysis of a honeycomb plate is studied. • Quasi-3D hyperbolic shear deformation theory which accounts for stretching effect have been used. • Influences of geometrical parameters, hygrothermal conditions, and different material parameters are explored. Halpin-Tsai and extended rule of mixture (ERM) schemes are used to evaluate the effective material properties of composite face sheets of a micro-scaled sandwich rectangular plate, to assess its thermo-elastic buckling behavior, in the current paper. For more details, it should be added that under evaluation model, which is resting on a Pasternak elastic foundation, is a honeycomb micro structure which is made of Nomex or Glass Phenolic and, to integrity, is patched with two same composite layers including graphene nanoplatelets (GNPs) dispersed through Epoxy resin. Great novelty of quasi-3D hyperbolic shear deformation theory (QHSDT) which accounts for stretching effect, virtual displacement principle, and modified couple stress theory (MCST) produced a good motivation to hire it to extract equations related to the current sandwich micro plate. Finally, variations of critical loads of thermal and mechanical buckling considered in figures and tables to examine the effect of different parameters' changes on them. As an example, based on acquired results, the sensitivity of thermo-mechanical critical buckling loads to the internal aspect ratio of honeycomb core ϕ 0 and force intensity distributions is proved where force intensity enhancement is caused critical buckling load reduction. [ABSTRACT FROM AUTHOR]

In this study, novel honeycomb structures with twisted feature were designed and manufactured by laser powder bed fusion (LPBF). The manufacturability, microstructure evolution of LPBFed honeycomb components with twisted feature were studied. The influence of twist angle on the compressive behavior of components was experimentally investigated and the underlying mechanism was revealed using FE simulation. Results revealed that the material relative density of LPBFed components was reduced with the increase of twist angle, caused by the enlarging overhanging area. Different cooling rate of melt pool at different parts along the building direction resulted in different microstructures. The twist angle significantly affected the compressive behaviors of honeycomb structures. When the cell number along each side was 3, the honeycomb structure with 30° twist angle exhibited the most uniform stress distribution under compression, leading to the highest specific compressive strength and energy absorption ability. The influence of cell number and wall thickness on compressive properties of honeycomb structures with 30° twist angle were investigated through finite element simulation, and results revealed that the structure with 0.75 mm wall thickness and 3 unit cells along each side showed the highest specific energy absorption ability. • Bio-inspired honeycomb structures with twist feature were designed and made by LPBF. • The effect of twist angle on microstructures of LPBFed components was studied. • The compression behaviors of components with different twist angle were studied. • FE simulation was used to study stress distributions of structures under compression. [ABSTRACT FROM AUTHOR]

The processing of high-precision aerospace parts requires not only ultra-precision machine tools, but also high-efficiency processing. However, in order to realize high-efficiency processing, besides optimizing the system and process parameters, some subversive research can also be done on the machine tool structure. In this paper, the lightweight research is mainly carried out on the structure of machine tool worktable. The traditional workbench is very "heavy" and "slowness". If the traditional workbench is subverted and reformed to reduce the weight, the processing efficiency will be improved qualitatively. Therefore, this paper studies the lightweight worktable of CFRP (carbon fiber reinforced polymer) in combination with the biological "honeycomb" shape. At first, the tensile, bending, compressive and laminar shear analysis of CFRP were carried out, and the comprehensive parameters were obtained. Simultaneously, the theoretical research and the honeycomb structure simulation and verification of CFRP worktable are carried out. The results show that the HACT (honeycomb arrangement of circular tubes) is 18.51% better than the SACT (straight arrangement of circular tubes) and 45.05% better than the OW (original worktable) by comparing and analyzing the weight of the three modes (HACT, SACT and OW). The actual weight of bionic honeycomb lightweight worktable is 1100 kg, while the simulation result is 1080.25 kg, with an error of 1.8%. Meanwhile, it is analyzed that the original workbench weight of the five-axis machining center is 2023 kg, while the simulation result is 1998.6 kg, with an error of 1.2%. The lightweight degree is reduced by 45.05%. However, the actual lightweight degree has been reduced by 45.63%. The error between simulation and actual is less than 1.3%. This kind of structural transformation has brought forward cutting-edge innovations to the machine tool processing industry. It provides a reference scheme for related enterprises in the future equipment renovation. [ABSTRACT FROM AUTHOR]

The development of asymmetric supercapacitors with good cycle stability and high energy density is becoming increasingly a research focus of energy storage systems. Herein, this work has reported a novel method to prepare CuCo 2 S 4 /Co-MOF (metal-organic framework) electrode materials. The electrochemical properties of materials are studied by changing the electrodeposition temperature. CuCo 2 S 4 -45, CuCo 2 S 4 /Co-MOF obtained at an electrodeposition temperature of 45 °C, has a microstructure of a multi-layer sheet-like two-dimensional ultra-thin honeycomb, which can shorten the diffusion path between ions/electrons. In addition, the specific capacitance of CuCo 2 S 4 -45 can reach 2879 F g−1 at 1 A g−1 as well as the capacity retention rate is 80.3% (2312 F g−1 at 20 A g−1). Asymmetric supercapacitor CuCo 2 S 4 -45//AC using activated carbon (AC) has excellent cycle stability (maintains 82.02% after 10,000 cycles), the energy density of 63.6 W h kg−1 at power density of 700 W kg−1. The results show that the material has great practical value. • Designed synthesis of copper-cobalt-sulfur electrode materials. • The CuCo 2 S 4 /CO-MOF has a 2D multilayer ultra-thin honeycomb structure. • The electrode materials exhibited high electrochemical performance with brilliant cyclicability. [ABSTRACT FROM AUTHOR]

Single-phase polycrystalline Li 2 PdO 3 has been synthesized at 640 ̊C in oxygen for the first time under ambient pressure. X-ray and neutron diffraction analyses show that the sample possesses a monoclinic layered structure belonging to the C 2/ m space group. Rietveld refinements of neutron powder diffraction data indicate ~10% Li–Pd site exchange and DIFFaX modelling manifest ~2% stacking faults present within LiPd 2 layers. A band gap of ~2.23 eV was calculated for the golden Li 2 PdO 3 using absorbance measurements. Thermogravimetric analysis of the sample shows that Li 2 PdO 3 is stable up to 730 ̊C under oxygen. A Curie tail is observed at low temperature magnetic measurements (T < 50K), yielding an effective moment of 0.038 μ B, possibly due to spin ½ impurities. • Single phase Li2PdO3 was synthesized and its crystal structure was elucidated. • Stacking Fault modeling yielded a density of ~2% occurring perpendicular to LiPd 2 layers. • A band gap of ~2.23 eV was calculated for Li 2 PdO 3 using UV–Vis absorbance. • Thermogravimetric analysis showed that Li 2 PdO 3 is stable up to 730 ̊C under oxygen. • Temperature <50 K, a Curie tail is yielded an effective moment of 0.038 μ B. [ABSTRACT FROM AUTHOR]

An analytical model is developed to investigate the in-plane mechanical properties of a thin-walled honeycomb structure. Nonlinear constitutive relations of honeycombs are presented based on in-plane large deformation analysis of a beam; elastic and plastic behaviors are both considered. These relations reflect the dependence of the equivalent stress, equivalent Young's modulus, and equivalent Poisson's ratio on deformation. Numerical simulation results indicate the effectiveness of the proposed method. Paramatric study is then conducted to investigate the effects of structural and material parameters on the honeycomb structure which is valuable for honeycomb structure design. • A theoretical model is developed to investigate the elastic-plastic behavior of a thin-walled honeycomb structure. • In-plane tension and compression analyses were carried out to reveal nonlinear constitutive relations of beams. • The modified factors are presented which depend on the shape and deformation of the honeycomb. • The proposed model can achieve a range of Poisson's ratio and Young's modulus values by parameters design. [ABSTRACT FROM AUTHOR]

Single-phase polycrystalline Li 2 PdO 3 has been synthesized at 640 ̊C in oxygen for the first time under ambient pressure. X-ray and neutron diffraction analyses show that the sample possesses a monoclinic layered structure belonging to the C 2/ m space group. Rietveld refinements of neutron powder diffraction data indicate ~10% Li–Pd site exchange and DIFFaX modelling manifest ~2% stacking faults present within LiPd 2 layers. A band gap of ~2.23 eV was calculated for the golden Li 2 PdO 3 using absorbance measurements. Thermogravimetric analysis of the sample shows that Li 2 PdO 3 is stable up to 730 ̊C under oxygen. A Curie tail is observed at low temperature magnetic measurements (T < 50K), yielding an effective moment of 0.038 μ B, possibly due to spin ½ impurities. • Single phase Li2PdO3 was synthesized and its crystal structure was elucidated. • Stacking Fault modeling yielded a density of ~2% occurring perpendicular to LiPd 2 layers. • A band gap of ~2.23 eV was calculated for Li 2 PdO 3 using UV–Vis absorbance. • Thermogravimetric analysis showed that Li 2 PdO 3 is stable up to 730 ̊C under oxygen. • Temperature <50 K, a Curie tail is yielded an effective moment of 0.038 μ B. [ABSTRACT FROM AUTHOR]

Here, we show a facile and one-step electrospinning strategy to fabricate multi-region scaffolds that display two main fibrillar microstructure arrays: honeycomb-like (HC) and randomly-oriented (RO), which are joined by an interface that aims to facilitate a smooth physical transition between them. Relevant design parameters including macropore size, fiber diameter, piezoelectric and mechanical properties were investigated. Our results show that polycaprolactone (PCL)-based scaffolds exhibited macropores in the HC and interface regions that could be tailored (from 867 ± 74 to 424 ± 27 μm and from 101 ± 10 to 80 ± 10, respectively) by increasing the electrospun polymer volume, while their fiber diameter distribution was not altered in a significant manner. Moreover, the local mechanical properties of these scaffolds changed in a discreet fashion according to each region's geometry, ensuring physical properties gradation from the RO to the HC zones. The versatility of this scaffold fabrication method was extended to the use of polyvinylidine fluoride (PVDF): while the macrostructural and mechanical properties were preserved, different fiber size distribution between the RO (353 ± 53 nm) and HC (251 ± 37 nm) regions as well as dissimilar fiber orientation were found, correlating with a variation in the piezoelectricity (β-phase fraction) within the scaffold. This fabrication technique could represent another alternative to engineer biocompatible multi-tissue systems with tunable structure and mechanics. Image 1 • A macroporous interface was found beneficial for moderate mechanical changes. • Different macropore size and fiber alignment in the same multi-region material. • Honeycomb-like structures favored the appearance of β-phase in PVDF materials. [ABSTRACT FROM AUTHOR]

Graphene oxide has been proven to be a promising anti-penetrant shield for Mg alloys against their over-rapid biodegradation, but the weak interfacial bonding between graphene oxide and Mg alloy is the main obstacle for effective protection. In this study, magnesium oxide (MgO) nanoparticles are coated on reduced graphene oxide (RGO) surface and then introduced in AZ61 alloy by laser melting, expecting to strengthen the interfacial bonding between Mg matrix and RGO. The results reveal that MgO acts as an interfacial bridge between Mg matrix and RGO and constructs nanoscale-contact and distortion areas with RGO. Moreover, MgO and α-Mg form a semi-coherent interfacial structure, in which an orientation relationship of MgO (‾200)//α-Mg (‾110‾2) and a small planar disregistry of 7.5% are detected. These interfacial characteristics indicate strong bonding at both the RGO/MgO and MgO/α-Mg interfaces, which thereby strengthens the protective capability of RGO. Compared with AZ61-RGO composite and AZ61 alloy, the AZ61-RGO/MgO composite present 13.3% and 34.0% decreases in corrosion rate, respectively. Meanwhile, the compressive strength and hardness of AZ61 alloy are also enhanced owing to the strengthened interfacial bonding. These findings demonstrate that the RGO/Mg interfacial strengthening is a promising candidate for improving the degradation behavior of Mg alloys. Unlabelled Image • A honeycomb structure with α-Mg grains encapsulated by RGO/MgO formed. • A semi-coherent structure formed at the interface of MgO/α-Mg. • Nanoscale-contact interfaces and distortion area formed at the RGO/MgO interface. • Stable honeycomb structure effectively acquiring a higher corrosion resistance the degradation of Mg alloys. [ABSTRACT FROM AUTHOR]

• 3D honeycomb-like MoSe 2 /rGO is designed and prepared as excellent Na+ stroage materials. • The honeycomb structure facilitates the fast Na+ transfer while buffer the volume expansion. • MoSe 2 /rGO exhibits outstanding cycle stability and excellent rate capacility. Transition metal dichalcogenides (TMDs) caused widespread concern because of their possess graphite-like two-dimensional structure, which allows Na+ reversible de-intercalation between the interlayers and contributes high theoretical capacity. However, the poor conductivity and structural instability greatly limited their application to sodium ion batteries (SIBs). Herein, three-dimensional (3D) honeycomb MoSe 2 /rGO nanocomposites with outstanding sodium ion storage performance were prepared. The MoSe 2 /rGO combined the advantages of MoSe 2 and rGO. The typical layered structure of MoSe 2 provide Na+ diffusion pathways and sufficient active sites, while the rGO increase conductivity and alleviate structural change during Na+ insertion/extraction process. The stable discharge capacity of MoSe 2 /rGO reaches 300 mAh g−1 at 0.1 A g−1 and retains 247 mAh g−1 after 100 times. It retains a high capacity of 214.7 mAh g−1 at 1 A g−1 and shows outstanding rate capability. The MoSe 2 /rGO//AC hybrid sodium-ion capacitors (HSIC) achieves a high capacitance of 56.7 F g−1 at 0.1 A g−1, it exhibits an energy density of 87.7 W kg−1 at a power density of 208.8 W h kg−1 and retains 50.5 W h kg−1 when it increases to 1051.4 W kg−1. The article brings up a novel opinion for designing porous TMDs based composites as ideal energy storage materials. [ABSTRACT FROM AUTHOR]

This work reports on a study regarding the plasmonic properties of a honeycomb-like structure that is formed by silver and gold nanoparticles. A honeycomb structure is proposed, and its plasmonic characteristics under the irradiation of a plane-wave light are numerically calculated, with several parameters being varied, including the radius of the nanoparticles, the separation between adjacent nanoparticles, and the polarization of the incident light. In the honeycomb, highly localized electric fields created by the oscillation of surface electrons are observed, and the associated electromagnetic hot spots are revealed in the vicinity of the noble metals. The results demonstrate that localized electric fields can be generated in the honeycomb-like structure, due to the plasmonic coupling between the metallic nanoparticles, and the hot spots can be adjusted by varying the values of the nanoparticles' radius, the separation, as well as the incident light's polarization. The plasmonic characteristics of the metal–nanoparticle honeycomb structure revealed in this study may be useful in the designs of plasmonic devices that utilizes localized, intensive electromagnetic hot spots. • Plasmonic properties of a honeycomb formed by metallic nanoparticles are studied. • Highly localized electric fields, and electromagnetic hot spots are observed. • Hot spots can be adjusted by varying nanoparticles' radius and separation. • Polarization of incident light can also affect hot spots' characteristics. [ABSTRACT FROM AUTHOR]

• The effect of hole diameter, pitch and hole diameter/pitch ratio of the metal porous honeycomb plate on flow boiling CHF was investigated. • The reduction in boiling area has a big influence on downward-facing flow boiling CHF. • Additional water supply through the metal porous media has significant CHF increase effect for some kinds of honeycomb plate. There is a strong need to find a feasible approach to increase the Critical Heat Flux in downward-facing flow boiling effectively for the In-Vessel Retention strategy in advanced nuclear power plants. In this study, we designed metal porous honeycomb plates with different structures and used them in downward-facing flow boiling experiment to find a honeycomb plate that can enhance CHF in the downward-facing flow boiling to the largest extent and investigate the enhancement mechanism. The effect of the honeycomb structure and water supply through porous media on CHF are investigated. It is found that the reduction in boiling area has big effect on CHF and water supply through the porous media has significant effect on increasing CHF for some kinds of honeycomb structures. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are applied in heat storage units, as they are able to accumulate the energy in the form of the latent heat of fusion. Thus, they can be used in recovering the excess of heat from various industrial processes. Their main weakness is their low thermal conductivity coefficient, which strongly limits their usage. In this paper, the benefits of the application of metallic inserts in heat storage PCM-based units were elaborated. Two kinds of Al–Si spatial elements (foams and honeycomb structures) were produced with the use of means of the investment casting method. Key factors influencing the technological process were established. The surface's roughness was measured in order to compare the obtained structures with their patterns in terms of the casting's accuracy. The compressive strength of the samples was tested, and their fatigue resistance was considered. The thermal performance of manufactured inserts in the PCM (paraffin)-based accumulator, supported by the calculation of heat fluxes, was analyzed and adjusted. Finally, further optimization was conducted in terms of the volume ratio of the metal insert to the PCM. Metallic inserts were found to significantly affect the performance of the entire energy storage system, as their use results in reduced charging time, a longer heat release time, increased maximum temperature, and a significant reduction in the temperature gradient in the heat storage unit. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of a new solid solution Li 2 Ru 1- x Rh x O 3 have been synthesized at 1000 °C in oxygen. Miscibility is found to exist for 0.4 ≤ x ≤ 1. X-ray and neutron diffraction analyses show that the whole series possesses a monoclinic layered structure belonging to the C 2/ m space group with lattice constants decreasing with increasing Rh content. For 0 < x < 0.4, a two-phase mixture, both C 2/ m structures, is formed. Time of flight neutron data refinements produced ~20% Li–Rh site exchange in the end member, Li 2 RhO 3. Defect modeled Li 2 RhO 3 structure yielded a 15% density of stacking faults perpendicular to the honeycomb layers. Magnetization measurements give an effective moment that increases with x as expected, and spin-glass-like hysteresis is observed below 10 K for x ≠ 0,1. Seebeck measurements show all of the compositions to be p-type above 300 K. The resistivity, ρ (T) , is well fit by a power law, ρ (T) ∝ T − ν , where 4.7 ≤ ν ≤ 9 depending on the composition, as opposed to Arrhenius-type behavior. This provides support for an electronic density of states that varies with energy as a power law, as opposed to that found for semiconductors or systems exhibiting variable range hopping, where charge transport is dictated by energy gaps. New Honeycomb layered Li 2 Ru 1- x Rh x O 3 solid solution series was synthesized with a miscibility gap of 0 < x < 0.4, Thus synthesized solid solutions exhibit gapless transport properties reminiscent of semimetals and resistivity data follows ρ(T) = ρ 0 T − ν relationship where ν > 4 leading to power law density of states below 300 K. Image 1 • New honeycomb layered Li 2 Rh 1- x Rh x O 3 solid solution series was synthesized with a miscibility gap of 0.4 ≤ x ≤ 1. • Stacking Fault modeling through DIFFaX yielded a density of ~15% occurring perpendicular to LiRh 2 layers. • Spin-glass-like hysteresis is observed for all the solid solutions below ~ 10 K. • Low temperature T < 300 K resistivity measurements fit well to ρ (T) ∝ T − ν relationship. [ABSTRACT FROM AUTHOR]

Porous graphene‐based composites offer immense potential for microwave absorption because of their light weight and high performance. In this work, a honeycomb structure filled with porous graphene is demonstrated with excellent radar‐absorbing properties. This graphene‐based composite reaches the maximum reflection loss (RL) of −15 dB at 8.8 GHz with only a thickness of 4.0 mm and an areal density of 0.26 kg m−2. Raman spectroscopy confirms the existence of graphene and scanning electron microscopy images reveal how these large graphene flakes are arranged to a three‐dimensional porous structure. In addition, a monolithic porous graphene aerogel, without the honeycomb core, and a RL simulation of it are also investigated for comparison, which reveals antipodal properties. This work shows that the insulated honeycomb structure increases the surface characteristic impedance of the whole composite material, which mainly contributes to the reduction of total reflection from the interface. Various structural influence factors have been analyzed, the results provide a new idea for exploring high‐performance microwave absorbers of graphene‐based materials. [ABSTRACT FROM AUTHOR]

Laser Engineered Net Shaping (LENSTM) is currently a promising and developing technique. It allows for shortening the time between the design stage and the manufacturing process. LENS is an alternative to classic metal manufacturing methods, such as casting and plastic working. Moreover, it enables the production of finished spatial structures using different types of metallic powders as starting materials. Using this technology, thin-walled honeycomb structures with four different cell sizes were obtained. The technological parameters of the manufacturing process were selected experimentally, and the initial powder was a spherical Ti6Al4V powder with a particle size of 45–105 µm. The dimensions of the specimens were approximately 40 × 40 × 10 mm, and the wall thickness was approximately 0.7 mm. The geometrical quality and the surface roughness of the manufactured structures were investigated. Due to the high cooling rates occurring during the LENS process, the microstructure for this alloy consists only of the martensitic α' phase. In order to increase the mechanical parameters, it was necessary to apply post processing heat treatment leading to the creation of a two-phase α + β structure. The main aim of this investigation was to study the energy absorption of additively manufactured regular cellular structures with a honeycomb topology under static and dynamic loading conditions. [ABSTRACT FROM AUTHOR]