Composite Field Research Articles

Analysis of crack-tip stress field in unidirectional fiber-reinforced composites based on 3D micromechanical model

Accurately clarifying the influence of cracks on the mechanical behaviors of unidirectional fiber-reinforced composites (UD FRCs) is of great significance for the structural integrity evaluation of UD FRCs with defects. Although several experiments and numerical analyses have explored the impact of cracks on stress field, satisfactory quantitative characterizations of crack size, a/W and location, Δ, fiber content, Vf have not yet been obtained. In this paper, the accurate and detailed microscopic models containing crack were first established and thoroughly validated. Then, a parametric study was conducted using three-dimensional micromechanical analysis to investigate how the crack size and location, fiber content affect the von Mises, stress triaxiality, Lode angle and J-integral of UD FRCs. Results showed that homogeneous models, whether isotropic or anisotropic, cannot accurately describe the mechanical behavior of cracked UD FRCs. The von Mises stress and J-integral are greatly influenced by the crack and fiber content, while stress triaxiality and Lode angle are not sensitive to changes in these factors. Further, the von Mises and J-integral increase with the decrease of Vf and the increase of a/W, but show a more complex trend in the variation of Δ. These findings will help clarify the failure mechanism of cracked UD FRCs and can be used for reliability evaluation.

Optimization design of a new hybrid magnetic circuit motor

The combination of permanent magnets and electrically excited windings creates an air gap magnetic field. The development of a hybrid magnetic circuit motor with an adjustable magnetic field is of great significance. This article introduces a hybrid magnetic circuit motor design that combines salient pole electromagnetic and permanent magnets. A tubular magnetic barrier has been designed to reduce inter-pole leakage and enhance the usage rate of permanent magnets in the hybrid magnetic circuit motor. The optimum eccentricity of the rotor has been accurately designed, resulting in an improved sinusoidal distribution of the air gap magnetic density waveform. An analysis of the static composite magnetic field under various excitation currents has been conducted, showcasing the capability of the hybrid magnetic circuit motor to stably adjust the air gap flux density level and output torque. A prototype has undergone comprehensive trial production and testing, conclusively confirming the machine’s superior output performance.

The response of atmospheric blocking and East Asian cold extremes to future Arctic Sea ice loss

The effect of Arctic warming on cold extremes over middle latitude remains a controversial and unresolved issue, particularly considering potential enhanced Arctic amplification in future scenarios. Here we examine the possible responses of winter cold extremes to the projected sea ice loss under 2 °C global warming scenario in four models, based on the atmosphere-only experiments of the Polar Amplification Model Inter-comparison Project (PAMIP). We find agreement with the increased responses of extreme cold days over East Asia (EA), characterized by longer duration or stronger intensity of temperature drop during cold events. Accordingly, most models exhibit a weak response of the Ural blocking in the corresponding composite circulation fields, whereas the westward movement of an anomalous anticyclonic system from eastern Siberia before the maturing of the Ural blocking is notable in four models. We suggest that this westward shifting pattern may prolong the duration of Ural blocking or modulate the strength of the Northeast Asian cold vortex, resulting in longer or stronger cold anomalies in EA. Accordingly, increased blocking frequency with a more pronounced westward response of shipment signals is also found over eastern Siberia, where a reduced meridional potential vorticity gradient (PVy) exists. The background of weak PVy can enhance the atmospheric nonlinearity, resulting in the anticyclonic anomalies less prone to dispersion and presenting a westward characteristic. Our results highlight the impact of the nonlinear response of circulation to Arctic sea ice loss. In contrast to more concerned Ural blocking influence, it is suggested that the downstream impact of eastern Siberia blocking on cold extremes in EA may be more pronounced in an enhanced Arctic amplification climate.

Effects of gas diffusion layer thickness on PEM fuel cells with composite foam-rib flow fields

Gas diffusion layers (GDLs) play a crucial role for the performance of proton exchange membrane fuel cells (PEMFCs). The utilization of composite foam-rib flow fields (CFRFFs) can alter the reactant gas transfer pattern, hence improving the efficiency of under-rib reactant gas transfer and water drainage. The impact of the cathode and anode GDL thicknesses (hc,GDL and ha,GDL) on the performance of CFRFF design is investigated by three-dimensional multiphase non-isothermal numerical simulation in this study. The results indicate that for the conventional rib flow field (CRFF) design, there is an optimal hc,GDL for optimal cell performance, while for the CFRFF design, as hc,GDL becomes thinner, the cell performance increases, and the trend is dominated by the variation of the oxygen concentration. Under a thin GDL, the rib width of the CRFF design should be as small as possible to minimize concentration polarization loss, while the rib width of the CFRFF design can be slightly larger. Furthermore, by decreasing the thickness of ha,GDL in both the CRFF and CFRFF designs, there is an increase in the dissolved water content in the ionomer of the cathode CL and a subsequent decrease in the Ohmic polarization loss.

Algorithmic Composition of Music Utilizing the Digits of Pi

As a matter of fact, algorithmic composition, the fusion of computational methods with music creation, has a rich history dating back to Pythagoras. On this basis, this paper explores the innovative intersection of mathematics, algorithms, and music, focusing on the translation of Pi's digits into a musical composition. Through a combination of manual and automated techniques, the research successfully crafts a melody using the minor pentatonic scale and traditional Chinese instruments, enriched by an algorithmically generated counter-melody. According to the analysis, the study reveals both the potential and limitations of this approach, with the fixed nature of the accompaniment and strict adherence to the pentatonic scale constraining musical diversity. Nevertheless, the research offers a novel perspective on mathematical representation in music, contributing to the broader field of algorithmic music composition. The findings open new avenues for personalized music creation, educational tools, and artistic exploration, highlighting the limitless possibilities when art and science converge.

Three-dimensional damage and rupture patterns of different thicknesses of rock mass with open joints under blast loading

There are an immense number of discontinuous structural surfaces represented by tensile joints in natural rock mass, in which the thickness of tensile joints determines the form how stress wave interacts with joint surface, which has a significant influence on the fracture behavior of jointed rock mass under blast loading. Open joint specimens were prepared using 3D printing technology, an indoor 3D blasting experiment was carried out with respect to different open joint thicknesses. Through CT scanning and three-dimensional reconstruction, the rupture and the distribution patterns of three-dimensional cracks of the post-blasting specimens were compared, and the rupture characteristics of the rock masses with different open joint thicknesses under blast loading were analyzed. The blasting process of the rock masses with open joints was inverted by AUTODYN numerical simulation software, the effects of open joint thickness on the propagation of stress wave and the three-dimensional damage characteristics of rock mass were revealed. Results showed that under the blast load, the wing cracks derived from the end of the open joints are greatly affected by the thickness of the joints and as the joint thickness increases, the annular derived cracks formed on the right outer surface of the specimen gradually decrease. In case of a change in the open joint thickness, the intensity at which the stress wave diffracts and transmits through the end of the joint will be directly affected. This makes it hard for the wing cracks at the end to initiate, the distribution density of the radial tension cracks traversing through the open joint surface attenuates obviously, resulting in the decrease of the fractal dimension and the damage extent of the specimen. As the thickness of open joints increases, the blast stress wave running through the joint surface will endure a time delay and reduced intensity, the closure of the joint surface gradually reduces, and the degree of stress concentration at the end gets weak. In the course of stress wave propagation, the rock mass on the back-blast side of the joint endures the combined actions of compressive stress field, tensile and tangential stress field and compressive and tangential stress field. As the thickness of open joint increases, the time point for the back-blast side to reach the peak stress is delayed, the intensity of the composite stress field subjected to compressive and tangential stress field decreases, and the normal displacements on the near-blast side and the back-blast side of the joint follow the opposite trend.

Fully optimized second-order estimates for the macroscopic behavior and field statistics of particle-reinforced viscoplastic composites

This paper is concerned with the characterization of the macroscopic behavior and statistics for the distribution of the stress and strain-rate fields in composites consisting of random and isotropic suspensions of rigid spherical particles in power-law viscoplastic materials. For this purpose, use is made of the Fully Optimized Second-Order (FOSO) homogenization method (Ponte Castañeda, 2016) in combination with recently developed estimates (Kammer and Ponte Castañeda, 2022) for the macroscopic properties of the associated ‘linear comparison composite’ (LCC). Special attention is devoted to the method’s ability to account for the dependence of the homogenized properties of the nonlinear composite on the Lode angle (third invariant) of the applied loading. It is found that, while, for large particle volume fractions c, the effective flow stress is only weakly dependent on the Lode angle, for dilute volume fractions, the dependence on the Lode angle becomes more pronounced. In the ideally plastic limit, as c tends to zero, the effective yield stress is shown to depend linearly on c for axisymmetric shear, while this dependence becomes weaker with a non-analytic leading-order correction of O(c/lnc) for pure shear loading. This strong dependence on the Lode angle at dilute concentrations is shown to be due to significant differences in the local deformation patterns, which become strongly anisotropic and localize for pure shear conditions, but do not for axisymmetric shear. In turn, the FOSO homogenization method is able to capture the statistical features of these different deformation patterns by providing consistent estimates for the covariance tensor of the strain-rate field fluctuations in the matrix phase, which tend to become more strongly anisotropic for the pure shear case. As c increases, the shear bands are deflected by the randomly dispersed spheres leading to a more isotropic distribution of the stress and strain-rate fields, which is consistent with a weaker Lode angle effect. The estimates can also capture the effect of strong particle interactions, including the existence of a rigidity threshold where the macroscopic flow stress and field fluctuations blow up.

An Updated Overview of Magnetic Composites for Water Decontamination.

Water contamination by harmful organic and inorganic compounds seriously burdens human health and aquatic life. A series of conventional water purification methods can be employed, yet they come with certain disadvantages, including resulting sludge or solid waste, incomplete treatment process, and high costs. To overcome these limitations, attention has been drawn to nanotechnology for fabricating better-performing adsorbents for contaminant removal. In particular, magnetic nanostructures hold promise for water decontamination applications, benefiting from easy removal from aqueous solutions. In this respect, numerous researchers worldwide have reported incorporating magnetic particles into many composite materials. Therefore, this review aims to present the newest advancements in the field of magnetic composites for water decontamination, describing the appealing properties of a series of base materials and including the results of the most recent studies. In more detail, carbon-, polymer-, hydrogel-, aerogel-, silica-, clay-, biochar-, metal-organic framework-, and covalent organic framework-based magnetic composites are overviewed, which have displayed promising adsorption capacity for industrial pollutants.

First deep search of tidal tails in the Milky Way globular cluster NGC 6362

I present results of the analysis of a set of images obtained in the field of the Milky Way globular cluster NGC 6362 using the Dark Energy Camera, which is mounted in the 4.0 m Victor Blanco telescope of the Cerro-Tololo Interamerican Observatory. The cluster was selected as a science case for deep high-quality photometry because of the controversial observational findings and theoretical predictions on the existence of cluster tidal tails. The collected data allowed me to build an unprecedented deep cluster field color-magnitude diagram, from which I filtered stars to produce a stellar density map, to trace the stellar density variation as a function of the position angle for different concentric annuli centered on the cluster, and to construct a cluster stellar density radial profile. I also built a stellar density map from a synthetic color-magnitude diagram generated from a model of the stellar population distribution in the Milky Way. The entire analysis approach converged toward a relatively smooth stellar density between 1 and ∼3.8 cluster Jacobi radii, with a slight difference smaller than two times the background stellar density fluctuation between the mean stellar density of the southeastern hemisphere and that of the northwestern one, with the latter being higher. Moreover, the spatial distribution of the recently claimed tidal tail stars agrees well not only with the observed composite star field distribution, but also with the region least affected by interstellar absorption. Nevertheless, I detected a low stellar density excess around the cluster’s Jacobi radius, from which I conclude that NGC 6362 presents a thin extra tidal halo.

The role of photo‐catalytically synthesized poly (N‐vinyl pyrrolidone‐methyl methacrylate)/CuO‐rGO nanocomposite as a filler for the reinforcement for epoxy system

AbstractThis study demonstrates the effective copolymerization of N‐Vinyl pyrrolidone and methyl methacrylate using reduced graphene oxide adorned with copper oxide nanoparticles (CuO‐rGO) acting as a catalyst when exposed to blue LED irradiation to generate random copolymer hybrid system of P(NVP‐co‐MMA/CuO‐rGO). We investigated the effects of this copolymer hybrid system of P(NVP‐co‐MMA/CuO‐rGO) on the mechanical, thermal and antibacterial properties of epoxy (DEGBA‐DETDA) composite. By employing two different concentrations of CuO nanoparticle, we assessed the reinforcement capability of the synthesized copolymer‐nanoparticle hybrid within an epoxy matrix. We observed that the composite sample comprising P(NVP‐co‐MMA/CuO‐rGO), having 0.5% of CuO‐rGO (Cu002) with respect to the epoxy concentration resulted in significant enhancements in fracture toughness. Further mechanical properties and thermal properties of the composite samples were studied using DMA, DSC and TGA. Microstructural properties and Mechanisms of toughening are elucidated through the examination of SEM images depicting the fracture surfaces. Moreover, the hybrid composites exhibited notable antibacterial activity against both E. coli and S. aureus compared to control. These findings highlight the copolymer hybrid P(NVP‐co‐MMA/CuO‐rGO) system's role as a multifunctional filler, enhancing epoxy composites' durability, functionality, and antibacterial performance. Our work advances the field of composites by showcasing the customized use of nanoparticle‐enhanced copolymers to improve material properties, providing valuable insights for the development of next‐generation composite materials.Highlights Achieved novel copolymerization of N‐Vinyl pyrrolidone and methyl methacrylate. CuO‐rGO successfully facilitates P(NVP‐co‐MMA/CuO‐rGO) nanocomposite formation. P(NVP‐co‐MMA/CuO‐rGO) nanocomposite proved as an effective filler for epoxy. P(NVP‐co‐MMA/CuO‐rGO) reinforced epoxy enhances toughness by 143% over neat epoxy Reinforced epoxy showed better efficacy against E. coli & S. aureus versus control.

The processing properties of photocatalysis assisted magnetorheological polishing based on TiO2–CI composite particles

With the development of optoelectronic wafers tend to be high brittleness, high hardness and high chemical stability, a single magnetorheological polishing is difficult to meet the application requirements of optoelectronic wafers. The quality and efficiency of magnetorheological polishing (MRP) of photoelectric wafer can be further improved by electric field assisted polishing or photocatalysis assisted polishing. In this paper, TiO2–CI functional composite particles were synthesized by sol-gel method, and a variety of polishing fluid with magnetic, electric and optical multi field effects were prepared. Silicon wafer and fused silica glass were polished by fixed-point centering polishing method, and the mechanism of photocatalytic assisted magnetorheological polishing (PMRP) was studied by comparing the polishing performance of the polishing fluid under different applied fields. The results show that when the polishing fluids prepared by oil-based liquid, the material removal rate is high under the action of a single magnetic field, but the polishing quality is poor. After polishing for 60 min, the height difference in surface profile ΔRz of fused silica glass is 0.67 μm. When the 2.5 kV/mm electric field is applied, the abrasive distribution can be controlled by electromagnetic composite field, and the stiffness distribution of polishing pad is more uniform, but it will reduce the material removal rate (MRR). Compared with the single magnetic field, the height difference in surface profile ΔRz is reduced by 73.1 % to 0.18 μm under the magnetoelectric compound field, which can obtain a more flattened surface quality. When light field and magnetic field are applied, water-based polishing fluid is used for polishing. Because UV light can induce photocatalytic reaction, the strong oxidation group ·OH generated in the photocatalytic reaction can oxidize the materials of workpiece surface into the lower hardness materials. Therefore, the material removal rate is increased by 249 % to 13.4 mg/h compared with that without light field, and the surface roughness was reduced by 69.32 % to 1.05 nm.

The Role of Diamonds Dispersed in Ferronematic Liquid Crystals on Structural Properties

A study of the role of diamond nanoparticles on 5CB liquid crystal composites with Fe3O4 nanoparticles is presented. Composite ferronematic systems based on the nematic liquid crystal 5CB doped with Fe3O4 magnetic nanoparticles and additionally bound to diamond nanoparticles (DNPs), of a volume concentration of 3.2 mg/mL, 1.6 mg/mL and 0.32 mg/mL, were investigated using both magneto-optical effect and surface acoustic waves (SAWs) to study the role of diamond nanoparticles on the structural properties of ferronematic liquid crystals. The responses of light transmission and SAW attenuation to an external magnetic field were investigated experimentally under a linearly increasing and decreasing magnetic field, respectively. Investigations of the phase transition temperature shift of individual composites were also performed. The experimental results highlighted a decrease in the threshold field in the ferronematic LC composites compared to the pure 5CB as well as its further decrease after mixing Fe3O4 with diamond powder. Concerning the transition temperature, its increase with an increase in the volume fraction of both kinds of nanoparticles was registered. The role of diamond nanoparticles in the structural changes and the large residual light transition and/or attenuation (memory effect) were also observed. The presented results confirmed the potential of diamond nanoparticles in nematic composites to modify their properties which could lead to final applications.

An improved composite ship magnetic field model with ellipsoid and magnetic dipole arrays.

In order to simultaneously maintain the ship magnetic field modeling accuracy, reduce the number of coefficient matrix conditions and the model computational complexity, an improved composite model is designed by introducing the magnetic dipole array model with a single-axis magnetic moment on the basis of the hybrid ellipsoid and magnetic dipole array model. First, the improved composite model of the ship's magnetic field is established based on the magnetic dipole array model with 3-axis magnetic moment, the magnetic dipole array model with only x-axis magnetic moment, and the ellipsoid model. Secondly, the set of equations for calculating the magnetic moments of the composite model is established, and for the problem of solving the pathological set of equations, the least-squares estimation, stepwise regression method, Tikhonov, and truncated singular value decomposition regularization methods are introduced in terms of the magnetic field, and generalized cross-validation is used to solve the optimal regularization parameters. Finally, a ship model test is designed to compare and analyze the effectiveness of the composite and hybrid models in four aspects: the number of coefficient matrix conditions of the model equation set, the relative error of magnetic field fitting, the relative error of magnetic field extrapolation, and the computational time complexity. The modeling results based on the ship model test data show that the composite model can be used for modeling the magnetic field of ships, and compared with the hybrid model, it reduces the number of coefficient matrix conditions and improves the computational efficiency on the basis of retaining a higher modeling accuracy, and it can be effectively applied in related scientific research and engineering.

Categories of rivers that formed vendian and lower cambrian sedimentary sequences, western part of east european platform (according to lithogeochemistry data)

Based on lithogeochemical data for fine-grained clastic rocks of the Volyn, Valdai and Baltic series of the west of the East European Platform (Belarus and Volyn, partly Lithuania), categories of rivers that transported fine-grained aluminosiliciclastics to the sinks were reconstructed. It is concluded that the formation of Vendian and Lower Cambrian sedimentary sequences developed in this area was controlled mainly by river systems similar to modern large rivers (rivers with a catchment area 100000 km2) and rivers draining sedimentary formations (rivers with a catchment area 100000 km2). The fine-grained aluminosiliciclastics transported by them came mainly from areas composed of rocks of the crystalline basement of the platform and, in part, sedimentary formations. The distribution of data points of Vendian and Lower Cambrian clay rocks on the diagrams (La/Yb)N–Eu/Eu* and (La/Yb)N–Th with fields of composition of pelitic and silty-pelitic sediments in the estuarine parts of modern rivers of different categories shows that mafic rocks of the Volyn-Brest large igneous province, apparently, were not suppliers of fine-grained aluminosiliciclastics in the indicated time intervals.

RGMU: A High-flexibility and Low-cost Reconfigurable Galois Field Multiplication Unit Design Approach for CGRCA

Finite field multiplication is a non-linear transformation operator that appears in the majority of symmetric cryptographic algorithms. Numerous specified finite field multiplication units have been proposed as a fundamental module in the coarse-grained reconfigurable cipher logic array to support more cryptographic algorithms; however, it will introduce low flexibility and high overhead, resulting in reduced performance of the coarse-grained reconfigurable cipher logic array. In this article, a high-flexibility and low-cost reconfigurable Galois field multiplication unit (RGMU) is proposed to balance the tradeoffs between the function, delay, and area. All the finite field multiplication operations, including maximum distance separable matrix multiplication, parallel update of Fibonacci linear feedback shift register, parallel update of Galois linear feedback shift register, and composite field multiplication, are analyzed and two basic operation components are abstracted. Further, a reconfigurable finite field multiplication computational model is established to demonstrate the efficacy of reconfigurable units and guide the design of RGMU with high performance. Finally, the overall architecture of RGMU and two multiplication circuits are introduced. Experimental results show that the RGMU can not only reduce the hardware overhead and power consumption but also has the unique advantage of satisfying all the finite field multiplication operations in symmetric cryptography algorithms.

Low-temperature compositing of graphene to nanodiamonds by thermal reduction of graphene oxide and photocatalytic properties

Graphene has become a research hotspot in the field of composites due to its special structure and excellent properties The common preparation methods of graphene matrix composites include solvent (hydrothermal) method, sol-gel method, chemical reduction method, electrochemical deposition method, etc. Nanodiamond/reduced graphite oxide (rGO) composites are directly synthesized by low-temperature heat treatment with nanodiamonds and graphite oxide (GO) powders as raw materials with the aid of GO thermal reduction at 195 °C. The degradation ability of samples to methylene blue (MB) under simulated sunlight was tested. Results indicated that GO was thermally reduced to graphene at low temperature, and rGO well combined with diamond. After the introduction of GO, the lattice of nanodiamond underwent distortion. Diamond and graphene formed a quasi-core–shell structure, and the interface between them was well bonded. The composite had a large specific surface area (Brunauer–Emmett–Teller value of 93.13 m2/g). The addition of GO enhanced the absorbance of the samples and reduced the bandgap of nanodiamond. When the ratio of nanodiamond to GO was 6:1, the sample exhibited excellent sunlight photocatalytic activity, and MB degradation rate reached 99.8 % within 40 min. The reduction reaction of GO at low temperature promoted its rapid combination with nanodiamonds. This method had the outstanding advantages of simple process, environment friendliness, and easy mass production.

Entanglement entropy along a massless renormalisation flow: the tricritical to critical Ising crossover

We study the Rényi entanglement entropies along the massless renormalisation group flow that connects the tricritical and critical Ising field theories. Similarly to the massive integrable field theories, we derive a set of bootstrap equations, from which we can analytically calculate the twist field form factors in a recursive way. Additionally, we also obtain them as a non-trivial ‘roaming limit’ of the sinh-Gordon theory. Then the Rényi entanglement entropies are obtained as expansions in terms of the form factors of these branch point twist fields. We find that the form factor expansion of the entanglement entropy along the flow organises in two different kind of terms. Those that couple particles with the same chirality, and reproduce the entropy of the infrared Ising theory, and those that couple particles with different chirality, which provide the ultraviolet contributions. The massless flow under study possesses a global ℤ2 spin-flip symmetry. We further consider the composite twist fields associated to this group, which enter in the study of the symmetry resolution of the entanglement. We derive analytical expressions for their form factors both from the bootstrap equations and from the roaming limit of the sinh-Gordon theory.

Musical connections: Nadia Boulanger and her artistic legacy in Romania

The article delves into Nadia Boulanger's artistic legacy in Romania, examining the profound influence of her teachings and the nuanced ways in which her distinctive personality resonated with Romanian musicians. Nadia Boulanger, a figure of intricate complexity, defies easy categorization, yet her indelible impact on the 20th century remains unquestionable. A composer, conductor, and educator, she became a beacon for virtually every prominent musician of her era. Moreover, her significance is heightened by the fact that she was one of the pioneering women in the field of composition. Nevertheless, there were also select Romanian artists who were fortunate recipients of her guidance. Through the prism of testimonials and meticulously preserved archival documents, we will summon their presence: Maria Cernovodeanu, Dinu Lipatti, Florica Musicescu, Cornel Țăranu. This commemoration stands as our tribute to 30 years of Francophonie in Romania and the craftsmen who contributed to it.

Fabrication of three dimensional graphene/carbon nanotube/copper foam field emitter by electrophoretic deposition and its emission properties

In this paper, the graphene/carbon nanotubes/copper foam (GR/CNTs/CuF) three-dimensional field emitters were prepared by electrophoretic deposition (EPD). For comparison, the graphene/copper foam (GR/CuF) and carbon nanotubes copper foam (CNTs/CuF) field emitters were also prepared by the same way and characterized by the several different methods. The turn on electrical field (Eon) of composite materials of GR/CNTs/CuF was obtained to be 0.85 V/μm. Threshold electric field (Eth) is 1.52 V/μm. The composite of GR/CNTs/CuF have a large contact area, a lower volume resistance and lower contact resistance, which is more easy to electron transport. The root of the CNTs or the fold tip of GR is fixed in the interlaced composite, and the tip or fold forms a stable micro tip emission structure, which enhanced the field strength factor. The field emission performances are significantly better than that of individual GR/CuF or CNTs/CuF field emitter. The GR/CNTs/CuF as 3D field emitters were prepared by EPD method with low cost and easy manipulation, which provided a good way for a large-scale preparation of composite field emitters.

Linear composite curvature MITC3+ flat shell elements

This paper introduces a novel linear composite curvature MITC3+ flat shell element, named κMITC3+, that combines the advantages of the MITC3+ theory for flexural (bending and shear) behavior and the Allman-like triangular element (which ensures a true rotation of drilling degrees of freedom and eliminates a spurious energy mode) for membrane behavior. To enhance the bending behavior of the MITC3+ approach, we propose an assumed composite curvature field that is constructed using a polynomial projection technique derived from the orthogonality condition of the compatibility equation in the Hu-Washizu principle. Since two additional internal cross-section rotations are interpolated by cubic bubble functions, a linear polynomial function of the admissible space is chosen that provides a significant enhancement of bending behavior. The κMITC3+ element successfully passes all critical tests and exhibits superior performance compared to the original MITC3+ element and the recent CS-MITC18+ element.