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Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. However, numerical modeling of geocell is always challenging due to its three-dimensional honeycomb structure. The limitations of the equivalent composite approach (ECA) led to the recent development of full 3D numerical models, which consider geocell-infill material interaction. This paper discusses the time-dependent performance of geocell-reinforced encased stone column-supported embankment considering the actual 3D nature of geocells using the finite element program ABAQUS. Parametric studies were carried out to study the stress transfer mechanism, vertical deformation of the foundation soil, and stress-strain variation inside the geocell pockets. It is found from the analyses that with the provision of a geocell layer on top of Geosynthetic Encased Stone Columns (GESC), the stress concentration ratio improved by 47% at the end of consolidation compared to GESC alone. Also, an 80% reduction in foundation surface settlement is observed with geocell-sand mattresses. The geocell-sand mattress decreased the bulging of the stone columns, and almost 80% of the stone column bulging occurred by the end of the embankment construction. The proposed model's numerical results show that the equivalent composite approach overestimated the stress concentration ratio and bearing capacity. The tensile stresses are non-uniformly distributed in the geocell pockets, and the maximum tensile force was mobilised at the geocell mid-height. Among the various geocell infill materials analysed, the aggregates were best suited considering the stress concentration ratio and vertical settlement. The numerical results supported the idea that encased stone columns with geocells at the embankment base can perform similarly to a geosynthetic reinforced piled embankment system, which is costlier but very efficient. When the modular ratio is more than 40, geocell-reinforced encased stone column-supported embankment is similar to GRPES. [ABSTRACT FROM AUTHOR]

The investigation of synthetic jet vortex rings flowing through a honeycomb is measured by two-dimensional particle-image velocimetry. The vortex is established using free synthetic jets generated by a piston–cylinder apparatus upstream of the honeycomb. On that basis, turbulence is obtained at circulation Reynolds numbers of ReΓ = 3437, 5155, 6874, and 8592, and Reynolds numbers of the synthetic jets of Resj = 561, 841, 1121, and 1402. The effects of the diameter Reynolds number (ReM = 41–449) and the length-to-cell ratio of the honeycomb (Φ = 4.2–12.5) on the characterization of flow are discussed in detail. A combinatorial similarity parameter that can characterize the effect of passive control on flow fields using a honeycomb is proposed and validated. The combinatorial similarity parameter, ReM/Φ, is determined through dimensional analysis and according to the change in momentum flux loss; its predictive capability is verified quantitatively based on the change in loss of kinetic energy and vortex-ring circulation. The evolutions of phase-averaged vorticity fields and finite-time Lyapunov exponents fields are nearly consistent using the close combinatorial similarity parameters. Furthermore, as indicated by the results, ReM/Φ responds to the combined effect of the relative magnitude of flow inertial and viscous forces, and the shape resistance of the honeycomb geometry to the flow-field–honeycomb interactions. Understanding the characterization of a vortex ring flowing through honeycomb is important for the accuracy of the prediction of turbulence models and the selection of the honeycomb size. [ABSTRACT FROM AUTHOR]

Abstract: The energetics, electronic and magnetic properties of 3d transition-metal (TM) atoms adsorbed low-dimensional Ge honeycomb structures have been systematically investigated from the spin-polarized density-functional theory calculations. For the two-dimensional Ge honeycomb structure, all TM atoms considered prefer to adsorb on the hollow site of the buckled hexagon in both single-sided and double-sided adsorption cases, with binding energies ranging between 3.27 and 5.92eV. Upon adsorption, the semimetallic 2D honeycomb Ge can change to either ferromagnetic or antiferromagnetic metals depending on both TM species and coverage density. For the one-dimensional structure, we found binding of TM atoms to hollow site of the edge hexagon yields the minimum energy state for all TM species considered and in all three AGeNRs examined which belong to different families. Depending on ribbon width, adsorbed TM species and adsorption concentration, most of the TM decorated AGeNRs can either be metals or semiconductors with ferromagnetic or antiferromagnetic spin alignment, except for Co-adsorbed ones which remain to be nonmagnetic. Interestingly, Cr or Mn adsorption can make certain AGeNRs to be half-metallic with a 100% spin-polarization at Fermi level which can be good candidates for future application in spintronic fields. Furthermore, the effect of the on-site Coulomb interaction on the stability of these half-metallic ribbons is also considered by performing L(S)DA+ U calculations, and the results show that the half-metallic ground state of the Cr-adsorbed ribbons is more robust than that of the Mn-adsorbed one. [Copyright &y& Elsevier]

Two 2D coordination polymetic networks compounds of [Na3MnIII6(μ6-O)(thme)4(PhCO2)6(H2O)]·OH (1) and [NaMnIII4MnII8O2(thme)4(N3)(OAc)8(AcOH)2(CH3O)4] (2) with 1,1,1-tris(hydroxymethyl)-methane (H3thme) as the ligand have been synthesized and structurally characterized by X-ray diffraction, IR spectra, and elemental analyses, where the homovalence hexanuclear Mn cluster in compound 1and the mixed-valence dodecanuclear Mn cluster in compound 2acted respectively as network nodes in the formation of honeycomb-shaped and rhombic grid-like layer structures. In addition, magnetic studies of 1reveal that antiferromagnetically coupled paramagnetic cluster behavior is operative within the hexameric Mn6cluster and 2exhibits antiferromagnetic coupling interactions and interesting frequency dependent in-phase as well as out-of-phase susceptibility signals are observed, respectively. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we consider the elastomechanical problems of a honeycomb structure of composite materials. A multiscale finite element method and the postprocessing technique with high accuracy are presented. We will derive the proofs of all theoretical results. Finally, some numerical tests validate the theoretical results of this paper. [Copyright &y& Elsevier]

This study investigates the cutting response of AL3003H18 hexagonal honeycombs loaded with vertical array blades. Quasi-static cutting tests were performed on aluminum honeycombs of various cell sizes and the same single-walled thickness (0.04 mm) using five groups of parallel steel blades of thickness 0.24 mm. The deformation mechanism was numerically simulated in the explicit solver LS-DYNA. In addition, the cutting process was described using a theoretical model based on dimensional analysis. The cutting response of honeycombs could be divided into three stages: elastic, transitional, and stable cutting. The cutting stress was found to decrease with increasing single-walled edge (SE) length. In an empirical analysis, the cutting force equation was derived as F = 1.3 C N c σ y t 1.92 d 0.30 l − 0.22 , where C is a constant, N c is the total number of cutting points, σ y is the yield strength of the matrix material, d is the cutting depth, and t and l are the thickness and length of an SE, respectively. In particular, the cutting force is proportional to the 0.30th power of the cutting depth and inversely proportional to the 0.22th power of the SE length. • Cell size effect in the cutting honeycombs loaded by parallel blades is observed in the experiments for the first time. • Three stages are included in the cutting honeycombs and shear strength of parent material dominates the first two stages. • Deformation mechanism is discussed and plastic deformation and stress concentration occur near the tip of the blades in honeycombs. • A theoretical model is derived to predict the cutting energy and cutting force. [ABSTRACT FROM AUTHOR]